NOVAtouch™ model 1 & 2 ™ and TouchWin version 1.1+ Operating Manual Original Instructions (English) Part Number 05170-1.1, Rev. C © 2015-2016 Quantachrome Instruments 1900 Corporate Drive Boynton Beach, FL 33426 USA NOVAtouch™ Operating Manual CONTACT INFORMATION Quantachrome Instruments 1900 Corporate Drive Boynton Beach, Florida, 33426 USA Tel: 1-561-731-4999 Fax: 1-561-732-9888 E-mail: qc.service@quantachrome.com qc.support@quantachrome.com www.quantachrome.com NOVAtouch™ Operating Manual QUANTACHROME WARRANTY POLICY Quantachrome Instruments warrants its instruments to be free from defects in material and workmanship for a period of one year from date of shipment under normal use and conditions. For the period commencing with the date of shipment and ending one year later, Quantachrome will, at its option either repair or replace any part within an instrument that is found by us to be defective in material or workmanship, without charge to the customer, at our facility or at a customer’s facility if the instrument purchased is backed by Quantachrome’s on-site warranty as evidenced by the sales contract. The customer is responsible for all transportation charges to our factory. Damages during the warranty period resulting from unstable utilities, operator error or unauthorized repairs will not be covered by this warranty. Parts purchases are warranted to be free of defects for 90 days from shipping date. The following limits apply to our warranty: Glassware, including Dewar flasks, is not covered under this warranty except if damaged during shipment. Claims for damage during shipping must be made in writing within 10 days of receipt of the goods. Expendable items are warranted for 90 days for other than glassware breakage. Such items include, but are not limited to, sample tubes, lamps, fuses, valve plungers, seals, O-rings & other seals, hoses, flexible tubing, thermocouple vacuum tubes, filters, oils and other fluids. Products sold by Quantachrome under their own brand name are not warranted by Quantachrome, but our best effort will be made to secure repair or replacement if found to be defective. Warranty is void in the event of modifications or repairs by persons other than Quantachrome’s service personnel, unless permission is given in writing for such repairs or modifications. Warranty is also void in the event of exposure to corrosive atmospheres of any kind. Prior authorization must be obtained before returning any item to Quantachrome Instruments. Items must be decontaminated before return to Quantachrome. 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Repairs made during the warranty period are guaranteed until the end of the warranty period or 90 days, whichever is greater. NOVAtouch™ Operating Manual TABLE OF CONTENTS Contents 1 INTRODUCTION ................................................................................................................................ 8 Summary of Features ............................................................................................................... 9 2 TECHNICAL SPECIFICATIONS ....................................................................................................10 Electrical ................................................................................................................................ 10 Physical ................................................................................................................................. 10 Environmental ....................................................................................................................... 10 Model Types .......................................................................................................................... 10 3 SAFETY .................................................................................................................................................11 Symbols Used in this Manual ................................................................................................ 11 Symbols Used on the Instrument ........................................................................................... 11 Safety Instructions — General .............................................................................................. 12 Safety Instructions – Cryogenic Liquids ............................................................................... 13 Safety Instructions — Heating Mantles................................................................................. 13 4 INSTALLATION .................................................................................................................................15 Unpacking and Placement ..................................................................................................... 15 Operation Voltage .................................................................................................................. 15 Analysis and Degassing Stations ........................................................................................... 15 Vacuum Connections ............................................................................................................. 16 Gas Inputs .............................................................................................................................. 16 5 INSTRUMENT COMPONENTS ....................................................................................................18 Mains Input............................................................................................................................ 18 Power Switch ......................................................................................................................... 19 Vacuum Fitting....................................................................................................................... 19 Gas Inputs .............................................................................................................................. 19 Cryogen Dewar Flask ............................................................................................................ 19 Heating Mantles and Outlets ................................................................................................. 20 Sample Cells and Glass Filler Rods ...................................................................................... 21 Cell Bulkhead Fittings ........................................................................................................... 22 Coolant Level Sensor (CLS) ................................................................................................. 24 P0 Cell .................................................................................................................................. 24 Quartz Rod Calibration Kit.................................................................................................. 24 Doors ................................................................................................................................... 25 Status Indicators .................................................................................................................. 25 6 TouchWin™ SOFTWARE ...................................................................................................................26 Installation ............................................................................................................................. 26 File ......................................................................................................................................... 30 Configure ............................................................................................................................... 34 Instrument Name (NOVAtouch) ........................................................................................... 46 Window ................................................................................................................................. 64 Help ....................................................................................................................................... 68 TouchWin™ Icon Toolbar ...................................................................................................... 69 Configuration of TouchWin™-CFR ....................................................................................... 70 Multiple Instrument Control .................................................................................................. 75 7 TOUCH SCREEN ...............................................................................................................................76 Status Bar .............................................................................................................................. 76 Page 6 of 161 NOVAtouch™ Operating Manual TABLE OF CONTENTS Home ..................................................................................................................................... 76 Manual Mode page ................................................................................................................ 77 Analysis Setup page .............................................................................................................. 78 Cell Calibration page ............................................................................................................. 81 Progress page ......................................................................................................................... 84 Degassing Page...................................................................................................................... 85 Results page ........................................................................................................................... 85 Maintenance page .................................................................................................................. 88 Logfile ................................................................................................................................. 95 Power Mode......................................................................................................................... 96 8 INSTRUMENT OPERATION .........................................................................................................97 Introduction ........................................................................................................................... 97 Cell Calibration ..................................................................................................................... 97 Sample Preparation................................................................................................................ 97 Unloading the Degasser ....................................................................................................... 106 Start Sample Analysis.......................................................................................................... 106 9 DATA ANALYSIS USING TouchWin™ ....................................................................................... 108 Opening Data Files .............................................................................................................. 108 Floating Menu ..................................................................................................................... 110 Tables, Graphs and Reports ................................................................................................. 110 Editing Analysis Data Information ...................................................................................... 111 Setting Data Reduction Tags................................................................................................ 111 Setting Data Reduction Parameters. .................................................................................... 113 Calculation of Heats of Adsorption ..................................................................................... 114 Review of the Data Analysis Methods ................................................................................ 114 Data Presentation ................................................................................................................. 119 10 THEORY AND DISCUSSION ..................................................................................................... 126 Surface Area ...................................................................................................................... 126 Pore Size by Gas Adsorption ............................................................................................. 130 Micropore Analysis ........................................................................................................... 137 Density Functional Theory and Monte Carlo Simulation Methods .................................. 146 Fractal Dimension Methods .............................................................................................. 149 Thermal Transpiration ....................................................................................................... 151 Heats of Adsorption .......................................................................................................... 152 11 APPENDIX ........................................................................................................................................ 154 Troubleshooting Guide ...................................................................................................... 154 Maintenance ...................................................................................................................... 156 Spare Parts List .................................................................................................................. 157 12 REFERENCES .................................................................................................................................. 160 Page 7 of 161 NOVAtouch™ Operating Manual INTRODUCTION 1 INTRODUCTION The NOVAtouch™ is a high-throughput surface area and pore-size analyzer. Employing manometric measurements the NOVAtouch™ determines quantitative physisorption data (amount of gas adsorbed/desorbed as a function of pressure) which are then used to calculate sample characteristics such as surface area and pore size distribution. To make the measurements, a suitable gas (referred to as the adsorbate) is quantitatively dosed, added to or removed from a sample cell containing the solid sample (adsorbent) maintained at a constant temperature below the critical temperature of the adsorbate – from a calibrated manifold of known volume and actively measured temperature. As adsorption or desorption occurs the pressure in the sample cell changes until equilibrium is established; the quantity of gas adsorbed or desorbed at the equilibrium pressure being the difference between the amount of gas admitted or removed and the amount required to fill the void space (that volume in the sample cell around the adsorbent and in the connecting gas pathways to a valve isolating the cell from the manifold). The NOVAtouch™ incorporates multiple features and enhancements for improved performance and ease-of-use. For example, it has three adsorbate gas inputs that allow a variety of gases such as N2, Ar and CO2 to remain connected and from which the instrument automatically selects according to the pre-programmed protocol. Helium, used to determine the void space when operating in the socalled “classical” mode has its own dedicated input, as does the user’s gas-of-choice for flowdegassing samples and/or backfilling evacuated sample cells. The instrument also includes everything required for sample degassing or preparation, separated from the analysis compartment yet within the overall footprint; no separate degassing unit is required. This capability uses either flowing gas or vacuum (LX model only, see below) together with the provided heating mantles and a programmable temperature profile that allows for extended and controlled sample preparation without the need for user intervention. The NOVAtouch™ is available in LX and non-LX versions. The LX features additional dedicated pressure transducers, one for saturation pressure (P0) and another that controls evacuation and backfill of samples in the preparation compartment. The LX version therefore is capable of both flow-type and vacuum degassing, whereas the non-LX version features just flow degassing. Both types use a single, external vacuum pump (required for analysis even when flow degassing has been used). All NOVAtouch™ models have an interactive, full color, multi-lingual touch-screen display that allows the user to enter sample information and initiate an analysis from a directory of user-defined analysis protocols, follow analysis progress in real time via text messages and automatically updated data plots, review results, check instrument status, access manual mode, start the degasser, and much more. After the initial transfer of analysis protocols and degassing temperature profiles from Quantachrome’s powerful multi-lingual TouchWin™ software, the NOVAtouch™ does not require direct interaction with a PC. However, TouchWin™ not only provides real-time, remote data acquisition and archiving, but also comprehensive off-line data reduction via an extensive suite of calculations, graphing and reporting options. TouchWin™ runs under 64-bit versions of Windows and communicates via Ethernet that allows for convenient placement of PC relative to the NOVAtouch™, even across a local network remote from the unit itself. Page 8 of 161 NOVAtouch™ Operating Manual INTRODUCTION Summary of Features Fully automatic analysis of one to four samples (depending on model type, see below) simultaneously. Long-life 2L Dewar allows measurement of detailed isotherms for the determination of pore size distributions. The smaller (blue) 1L Dewar is suitable for quality control/assurance applications where a large capacity Dewar is unnecessary, i.e., in the absence of a requirement for full isotherm measurement (pore size distributions). In-board sample preparation of up to four samples simultaneously. Intuitive touchscreen used for the following operations: • Starting/stopping degassing • Starting analyses locally from a shortlist of protocols • Monitoring status • Aborting analysis • Reviewing results • Manual mode functions • Calibration functions Powerful Windows-based TouchWin™ software allows: • Creation of multi-step degassing temperature profiles (sent to instrument) • Creation of detailed analysis protocols (sent to instrument) • Remote starting of analysis • Real-time data display • Pore size distribution calculations • Automatic printed report generation • Archiving of data Comprehensive accessory and consumable kit included. Page 9 of 161 NOVAtouch™ Operating Manual TECHNICAL SPECIFICATIONS 2 TECHNICAL SPECIFICATIONS Electrical NOVAtouch™ 2.1.1 Voltage: Frequency: Power (max): Connection: 2.1.1.1 100, 120, 220, 240 V (see serial number plate on the side of the instrument) 50/60 Hz 350 W Grounded, single-phase mains outlet Heating Mantles Voltage: Frequency: Power (±10%): Connection: 110 – 120V 50/60 Hz 105 W each Dedicated outlets in NOVAtouch™ degassing compartment Physical Height: Width: Depth: Weight: 82.9 cm (32.7 in) 61.6 cm (24.3 in) 49.2 cm (19.4 in) 42.2 kg (93 lbs.) Environmental Temperature: Max. Relative Humidity: 15 C – 40 C 80 %. It is recommended wherever possible to operate the unit in an air- conditioned space at RH<50%. Model Types 2.4.1 LX Available with one up to four analysis ports. Dedicated P0 cell Dedicated P0 transducer Vacuum degassing Degassing backfill transducer Flow degassing 2.4.2 Standard (Non-LX) Available with one up to four analysis ports. Dedicated P0 cell Flow degassing Page 10 of 161 NOVAtouch™ Operating Manual SAFETY 3 SAFETY Symbols Used in this Manual HOT! This symbol denotes a possible hazard to the operator due to high temperatures. ! CAUTION! This symbol denotes a hazard that could result in damage to the instrument. ! WARNING! This symbol denotes a hazard that could result in injury to the operator. WARNING! This symbol denotes a low-temperature hazard that could result in injury to the operator. NOTE! This symbol denotes an important detail. TOOLS REQUIRED: This signifies that tools are required for the described action. HAZARD: This denotes that an environmental hazard might be present. Symbols Used on the Instrument ! CAUTION! Use high purity gases. Be sure to connect gas lines to their appropriate input fitting; incorrect gas supplies will lead to erroneous results. HOT! Use caution at all times when handling the heating mantles. Page 11 of 161 NOVAtouch™ Operating Manual SAFETY Safety Instructions — General Read and follow all the instructions in this manual. This instrument was designed for indoor laboratory use only. It is not designed to be operated in a flammable atmosphere or where dust explosion hazards may be present. Position the instrument for easy access to the on/off switch. This instrument shall only be operated by a competent user who has received training appropriate for the intended purpose. Management responsible for the use of this instrument shall ensure that the user is familiar with the contents of this manual and any necessary safety precautions before working with the instrument. Comply with all national health and safety standards. This may include, but it is not limited to: barrier protection, protective eyewear, gloves, and suitable laboratory attire when operating or maintaining this or any other automated laboratory analyzer. Inform user of hazards associated with the gas(es) used and the sample(s) being tested. Operate this instrument only at the voltage specified on the serial number plate on the side of the instrument. Only use the mains power cord supplied with the unit or one that is rated for the voltage and power stated in the specifications section of this manual. This instrument must be disconnected from the mains for any cleaning, maintenance or service. Do not position the instrument in such a way that it would be difficult to remove the power cable. Do not make any unauthorized modifications to this instrument. Use replacement fuse(s) only as indicated in the service section of this manual or on the instrument. The fuse(s) are not intended to be replaced by the operator but by a qualified electrical technician. When attaching a plug to the international power cord, be sure to follow the color code: brown = live, blue = neutral, green/yellow = earth ground. When not in use for more than a few days, unplug the machine from the mains power supply. If it is not going to be used for a considerable amount of time it should still be protected from possible damage and water splash. The original packaging material is suitable as protection for long term storage. The instrument should always be stored and transported the “right way up”, i.e. the same orientation in which it is used. HAZARD: Observe federal and local regulations regarding handling and disposal of used samples. Page 12 of 161 NOVAtouch™ Operating Manual SAFETY Safety Instructions – Cryogenic Liquids ! WARNING! When filling the Dewar flask with liquid nitrogen (LN2) care must be taken to prevent it from getting between the glass insert and the outer cover, as this may cause the glass to implode. WARNING! This symbol denotes a low-temperature hazard that could result in injury to the operator. Because the Dewar flask can shatter unexpectedly, a protective face shield, safety glasses, and gloves should be worn when filling the flask. When using a gas other than N2 or Ar at its respective boiling point, do not use the Calculate P0 option while calibrating an empty cell or during analysis. Safety Instructions — Heating Mantles HOT! The outer surfaces of the heating mantle may become hot during use. Do not hold hot heating mantles without wearing protective gloves. Never insert fingers inside the pocket to determine if the mantle is heating up. Do not place a hot heating mantle on a surface which is not heat resistant. Switch off when not in use. ! Quantachrome heating mantles are designed only for heating sample cells for the purpose of degassing. Quantachrome heating mantles must only be used on Quantachrome instruments designed for the mantle type. Use heating mantles only on instruments with properly functioning, calibrated heating mantle stations. WARNING! The heating mantle must have a sample cell in the pocket when in use. Ensure that no sample adheres to the outside of the sample cell. Do not use wet, broken, cracked, or chipped sample cells. Do not insert spatulas, screwdrivers or other objects into a heating mantle. Never place the sample to be degassed directly into the heating mantle. Do not allow liquids to come into contact with the heating mantle and do not handle heating mantles with wet hands. Do not allow dust to accumulate on, nor in, a heating mantle. Do not expose the heating mantle to a corrosive atmosphere of any kind. Do not make any modifications to any Quantachrome heating mantle. Do not remove the serial number tag from the heating mantle. Removing the tag will void the warranty. Page 13 of 161 NOVAtouch™ Operating Manual SAFETY Insert the power plug of a heating mantle only into the socket provided for that purpose on the NOVAtouch™. Do not insert the power plug of a heating mantle into any mains supply socket. Do not insert the plug of any other device into the heating mantle socket on the NOVAtouch™. Insert the thermocouple plug of a heating mantle only into the socket provided for that purpose on a Quantachrome instrument. Do not insert the thermocouple plug of a heating mantle into any other socket. Do not insert the plug of any other device into the thermocouple socket of any Quantachrome instrument. ! ! WARNING! Always ensure that the power plug and thermocouple plug of one heating mantle are inserted into the sockets of the same heating mantle station. Never insert the power plug of one mantle into the power socket of a different mantle. Use care and ensure that the thermocouples are installed on the same station that is providing the power to the mantle. CAUTION! Do not cross-wire the heating mantles. This will cause the mantles to overheat. Page 14 of 161 NOVAtouch™ Operating Manual INSTALLATION 4 INSTALLATION Unpacking and Placement For best results the instrument should be installed on a level bench, suitable for supporting in excess of 50kg, away from direct sunlight, heaters and air conditioner units. Local regulations may require use of local ventilation and/or protective equipment. Position the instrument so that the on/off switch can be easily accessed. Remove the instrument from its shipping box and place it on the bench where it will be operated. ! WARNING! Take precaution when lifting the unit since it weighs 42.2 kg (93 lbs.). Handle the instrument with two or more persons trained in proper lifting techniques and/or a mechanical lift device. Unpack the supplied parts and accessories and confirm them to the packing list. If any parts are missing or damaged immediately notify Quantachrome or your local authorized representative. 4.1.1 Earthquake Zones The NOVAtouch™ can be secured to the bench to prevent toppling in the case of a seismic event. Contact Quantachrome for details. Operation Voltage The NOVAtouch™ is shipped for operation with the voltage specified in the purchase order. However, it is designed for operation on 100V, 120V, 220V or 240V, 50/60 Hz. ! CAUTION! The unit must not be operated at a voltage other than that indicated on the serial number plate; the Corcom power input module must match the serial number plate. If the unit is relocated and must be used at a different voltage than that specified, the user must contact Quantachrome Service Department for detailed instructions on changing the voltage settings. Analysis and Degassing Stations The sample cell ports in both the analysis and degassing stations must have the stainless steel dowel inserted into the bulkhead fittings before turning on the NOVAtouch™. The stainless steel dowels use the same O-rings and cell adapters as the 9mm cells. Page 15 of 161 NOVAtouch™ Operating Manual INSTALLATION Vacuum Connections TOOLS REQUIRED: Flat head screwdriver or 5/16’’ wrench (not supplied). The NOVAtouch™ is supplied with a centering ring and clamp to connect the vacuum hose to the fitting on the instrument. If the vacuum pump is supplied with the NOVAtouch™, a similar set of hardware is supplied to connect the hose to the pump. A pump capable of reaching 10 milliTorr should be used. Vacuum Connection (on ride side of instrument) Ring Clamps 90° Elbow Centering Rings NW-16 Stub Hose Clamp Vacuum Hose Nova Touch is supplied with a 90 degree elbow (P/N 44242) to aid in NOTE! assembly of vacuum connections. Page 16 of 161 NOVAtouch™ Operating Manual INSTALLATION Gas Inputs TOOLS REQUIRED: 1 1/8” wrench, 7/16” wrench and 3/8” wrench (not supplied) The NOVAtouch™ has five gas input fittings located on the right side of the instrument: three gas input fittings reserved for adsorbates (analysis gases), one is reserved for helium and another for degas backfill/flow gas. Helium gas must be connected to its labeled port for those analyses programmed to use Helium Mode. It is recommended to use high purity helium and adsorbate gases (99.99% or higher). Attach a dual stage, stainless steel diaphragm regulator to the tank using a 1 1/8” wrench. Connect one end of the gas input line (supplied) to the regulator with a 7/16” wrench, and the other end to the gas-input fitting on the unit with a 3/8” wrench. It may be necessary to obtain an adapter in order to connect the input line to the regulator. The recommended regulator assembly is available from Quantachrome (P/N 01207, 0-25 PSI), comes complete with a shut-off valve, CGA580 cylinder fitting and 1/8” outlet fitting. The regulator should be set to deliver 8 psig (55 kPa) for all gases. For Helium: connect the gas input line to the regulator. Set the regulator to 8 psig and allow the gas to flow through the line to purge out atmospheric gases. Then connect the gas input line to the Helium gas-input fitting. If the adsorbate is used as the backfill/flow gas, use a tee which allows the gas to be supplied to the two fittings (adsorbate input 1 and the degas flow/backfill input) using one tank. A line with a compression fitting on one end is provided with the instrument. Figure 4-1, Backfill Tee The regulator assembly with P/N: 01207 is suitable for inert gases such as NOTE! He, Ar, and N . The relevant P/N for CO is: 01207-CO2. 2 2 Page 17 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS 5 INSTRUMENT COMPONENTS Analysis bulkhead fittings Touch screen Degassing bulkhead fittings CLS Heating mantle hooks (LX model only) Dewar flask Heating mantles Ethernet port Power on/off Mains voltage Mains power input Figure 5-1, Instrument Components Mains Input The voltage indicated on the power entry module must match the voltage on the serial number plate. If it does not, STOP, and contact Quantachrome or its local representative. The power module accepts a standard IEC-320 detachable instrument power cord. Page 18 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS Power Switch The power switch is located on the left side panel of the NOVAtouch™. The position of the switch indicates the status, do not rely on the light inside the switch to indicate whether the unit is switched on. Vacuum Fitting The vacuum uses a standard KF-16 flange fitting; located on the right side of the NOVAtouch™. The connecting hose, clamp, flange and centering ring are supplied with the instrument. A vacuum pump capable of achieving at least 50 milliTorr is required, a vacuum pump capable of 10 milliTorr is recommended. Figure 5-2, Vacuum Fitting Gas Inputs The NOVAtouch™ has five gas input fittings on the right side of the NOVAtouch™: three adsorbate ports, one helium port, and one backfill port. A backfill line is provided to allow an easy connection between the first adsorbate gas input and the backfill gas input. See Figure 4-1, Backfill Tee. Cryogen Dewar Flask The NOVAtouch™ is supplied with a two liter Dewar (P/N 74215), which will hold liquid nitrogen (LN2) for more than 30 hours (capable of full mesopore size distribution measurements), or a one liter Dewar (P/N 74218) used for short cells and is suitable for applications requiring BET surface area/STSA measurements. The Dewar is placed in the lift-drive cup. NOTE! The Dewar manufacturer recommends that the following procedure be adopted: (i) Prior to first use, all the packing material from the inside of the Dewar must be removed. (ii) Wash the Dewar with hot soapy water, rinse with distilled or deionized water and either air dry or clean with a lint free towel. This is to ensure a clean, dry, and contamination-free Dewar. Page 19 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS The Dewar flask holds the coolant used for the analysis, usually liquid nitrogen; it should be filled to the level indicated by the Dewar clip prior to each analysis. Figure 5-3, Dewar Flask with Coolant Level Indicator (Dewar clip) Attached ! CAUTION! Always use short sample cells, short Po cell and short CLS with the 1L (blue) Dewar; otherwise breakage of cells and/or Dewar is likely. Heating Mantles and Outlets Two heating mantle power outlets are provided in the degassing compartment. The thermocouple plugs are inserted into the jacks located in the same compartment. The heating mantles will not operate correctly unless both the power cord and thermocouple are plugged in. NOTE! Always ensure that the power plug and thermocouple plug of one heating mantle are inserted into the sockets of the same heating mantle station. Do not insert the power plug of a mantle into the power socket of one heating mantle station and the thermocouple plug of the same mantle into the thermocouple socket of a different heating mantle station. For safety instructions regarding the heating mantle see Sect. 3.5. Page 20 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS Figure 5-4, Heating Mantles Positioned for Flow Degassing Figure 5-5, Heating Mantles Ready for Vacuum Degassing (LX model only) NOTE! The mantle hooks used to support the mantles while vacuum degassing sample cells are provided only in the LX model. Sample Cells and Glass Filler Rods Sample cells are available with outside stem diameters of 6, 9 and 12 mm (internal diameters of 4, 7, and 10 mm respectively), in “long” and “short” versions. Each cell should be numbered in the space provided (if analyzing in NOVA mode) and used with the appropriate glass filler rod. After performing a cell calibration, ensure that the same filler rod is always used for that particular station. For most users, standard (bulbless) cells of a given stem diameter can be given a single identifying number and used interchangeably. Page 21 of 161 NOVAtouch™ Operating Manual ! INSTRUMENT COMPONENTS CAUTION! Never use long cell (sample and P0) with the 1L (blue) Dewar; otherwise breakage of cells and/or Dewar is likely. Cell Bulkhead Fittings The fittings, designed to accept 6, 9, and 12 mm size cell stems, use an adapter sleeve and O-ring to secure the cells in position while creating a vacuum-tight seal. The correct size O-ring and adapter must be used with each corresponding cell. Be sure to use only one O-ring when installing a cell into the fitting; using two O-rings (of any size) are likely to cause a leak leading to erroneous results. Cell stem is inserted into the bulkhead fitting The correct sized O-ring for the cell stem must be used The correct sized adapter for the cell stem must be used Knurled ring for tightening/loosening the O-ring compression fitting Figure 5-6, Cell Fittings (not to scale) Page 22 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS Bulkhead positions . Figure 5-7, Orientation of Sample Bulkheads Figure 5-8, Removable Decal The removable decal can be placed anywhere the user deems appropriate. Note the alignment of the sample cell station number relative to the front of the instrument. Page 23 of 161 NOVAtouch™ Operating Manual INSTRUMENT COMPONENTS Coolant Level Sensor (CLS) Coolant level is maintained at a constant level around the cell, and at a position which minimizes the so-called “cold-zone” of the cell (thereby improving sensitivity). That level is maintained by a coolant level sensor (P/N 00080-CLS) and a sensitive electronic circuit which adjusts the Dewar height to compensate for the evaporation of coolant during the analysis. The CLS is installed next to the analysis cell bulkhead fittings using a BNC connector. The NOVAtouch™ is supplied with a CLS suitable for both liquid nitrogen and liquid argon. A water float sensor (P/N 00080-H2O-NT) is available for measuring isotherms, for example, at 0oC using ice/water. Figure 5-9, Coolant Level Sensor (CLS) The CLS (P/N 00080-CLS) must be used; otherwise the sample will never be NOTE! cooled. When using short cells (sample and P ) the short CLS (P/N 00080-CLS-S) 0 must be used. P0 Cell The P0 cell is dedicated to measuring the saturation vapor pressure, P0, of a gas at its own boiling point. When measuring P0 is part of an analysis protocol, the instrument liquefies a small amount of pure adsorbate in the P0 cell when the Dewar is in the raised position. The equilibrium P0 is measured either by a dedicated pressure transducer (LX models) or the main manifold transducer (non-LX models). If used, the instrument safely removes the condensed gas via the vacuum system before the Dewar is lowered. To help stabilize saturation pressure (P0) readings, the cylindrical collar (P/N 04000-10844) provided should be slipped over the stem of the P0 cell before it is installed. The P0 collar should rest above the bulb. A P cell is not required if, enter P or calculate P is chosen at the time of the NOTE! analysis. 0 ! 0 0 CAUTION! Never use a long P0 cell with the 1L (blue) Dewar; breakage of cells and/or Dewar is likely. Use a short P0 cell (P/N 74027-S). Quartz Rod Calibration Kit Manifold volume calibration is performed using the calibration kit which includes: • Calibration cell with spring • Calibrated quartz rod Page 24 of 161 NOVAtouch™ Operating Manual • INSTRUMENT COMPONENTS Quantachrome certificate for quartz rod volume Doors The NOVAtouch™ rotating doors serve to eliminate drafts (particularly in the analysis compartment), and minimize frost build up around the Dewar. It is recommended that the doors be kept closed whenever possible. The roller-bearings are factory-lubricated and should not require regular maintenance. Status Indicators The status indicators display the present state of the heating mantles and Dewar. At the top of the status indicators is the “Mantles Reset” button used to reset the mantles when they have reached an over-temperature condition. The “Enabled” light will always be on when the mantles are connected and functioning properly. The “Heat Cmd” indicates that the mantle is receiving the command and currently heating. The indicators available for the Dewar are: Up Cmd, Send, Down Cmd, and Received. The “Cmd” indicators will blink when the command to move the Dewar in the respective direction is being received. NOTE! If the heating mantles have reached an over-temperature condition they will be placed into a shutdown state, which can only be released by resetting the mantles. The mantles can be reset using the “Mantles Reset” button at the top of the status indicators. Figure 5-10, Status Indicators Page 25 of 161 NOVAtouch™ Operating Manual SOFTWARE 6 TouchWin™ SOFTWARE Installation 6.1.1 TouchWin™ Program CD The installation CD contains the TouchWin™ software. It can be installed on any Windowsbased PC (Windows® Vista and higher). Ideally, before proceeding with the installation, a backup copy of the installation CD should be made and stored in a safe location (preferably not the same place as the original CD). TouchWin™ will need to be installed on at least one PC before it can properly operate the NOVAtouch™ instrument. NOTE! If upgrading the software and FULL installation is selected, it will overwrite the configuration files regardless of date/time stamp (materials data, reports, instrument configuration) with “factory” defaults. 6.1.2 TouchWin™ Setup Follow the installation steps below: 1. Insert TouchWin™ installation CD in the CD-ROM drive and follow the installer prompts. If auto insert notification is enabled, the startup menu will launch automatically. If not, open the CD-ROM drive in explorer, and manually run START.EXE. Figure 6-1, TouchWin™ Setup Screen 2. Click “Next”. Page 26 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-2, TouchWin™ “Select Additional Tasks” Screen To choose a desktop icon or Quick Launch icon select these items. Click “Next”. Review the items selected on the “Ready to Install” page before choosing “Install”. To change any of the settings use the “Back” button and make the appropriate changes. Figure 6-3, TouchWin™ “Ready to Install” Screen After “Install” is selected, the window shown below will open showing the progress of the software installation. Page 27 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-4, TouchWin™ “Installing” Screen When the software installation is completed, to launch the software automatically select the “Launch Quantachrome TouchWin” and click “Finish”. If you do not wish to launch the software at this time ignore the selection and click “Finish”. Figure 6-5, Completed Installation Screen After installation is complete TouchWin™ will be ready to run. The software may be opened from the Quick Launch or Tool Bar (based on previous selections). Page 28 of 161 NOVAtouch™ Operating Manual 6.1.3 SOFTWARE Instrument – PC Connection To begin using TouchWin™, perform the following steps: 1. Connect the NOVAtouch™ to a computer or network using an Ethernet cable (P/N 26102-25). 2. Power on the NOVAtouch™. Allow the instrument to run through the initialization sequence. When this sequence is finished, the Home Screen will be available on the NOVAtouch™ display. The instrument is now available for use. 3. Navigate to the Maintenance Page on the Touchscreen and select the Network option. (See Maintenance Page details in Sect. 7.9.5, Network Settings.) 4. Enter the desired IP address. Contact your IT department for help with assigning an IP address. 5. Using TouchWin™, click on the Instrument name drop down menu; the default name is “NOVAtouch” and select “Communication Parameters” to open the “Edit Profile” window. Input the designated IP address (the same address that was used in Step 3) and click “OK”. (See also 6.4.3, Communication Parameters.) Figure 6-6, TouchWin™ “Setup Completion” Screen become the new title of the “Instrument/NOVAtouch” drop down menu. NOTE! The instrument name can be set using the “Edit Profile” window. This will 6. While still using TouchWin™, return to the Instrument drop down menu and click “Connect” to establish communication with the NOVAtouch™ instrument. NOTE! The TouchWin™ interface is required to setup and upload both degassing temperature profiles and analysis protocols. These procedures can be started from the touch screen repeatedly thereafter. 6.1.4 Working with TouchWin™ The following Sections: 6.2 – 6.7 , address the TouchWin™ software features systematically. What follows is intended to be used as a reference. The TouchWin™ program uses a standard Windows-style interface consisting of menus, buttons, Page 29 of 161 NOVAtouch™ Operating Manual SOFTWARE and various dialog windows. The main menu bar (shown in the center of Figure 6-7) contains five drop-down menus providing access to all program functions as described below. Figure 6-7, TouchWin™ Drop Down Menus File The “File” drop down menu provides the user with access to data files. This menu also provides “Change User” and “Exit” (close program) functions. 6.2.1 New > Physisorption Overlay Select “New > Physisorption Overlay” to create an overlay file (.qcuPhOverlay). First, select the primary file from the file explorer window. To add additional files in the overlay, right click and select “Manage Isotherms”. Page 30 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-8, Physisorption Overlay Isotherm When the overlay manager opens, select “Add” to add files. Duplicating a selection is desirable to modify only one instance of the graph and not the other. To remove a file, select the file’s field then select “Remove”. Figure 6-9, Physisorption Overlay Manager Once multiple files have been chosen, to edit their presentation select the file’s field in the Overlay Manager, then select “Edit”. This will prompt a contextual Floating Menu (shown below) for the file whose field is selected. Figure 6-10, Edit Function Floating Menu NOTE! To use the overlay file in the future, save the file that has been created by using either the “Save” or “Save As” functions (from the “File” drop down menu). Page 31 of 161 NOVAtouch™ Operating Manual 6.2.2 SOFTWARE Open When the “Open” option is selected from the “File” drop down menu, the explorer window will open for selection. There are two primary file types: .qcuPhysIso (for physisorption files) and .qcuPhOverlay (for overlay files). Because the two primary file types are independent, not all of the data will be displayed in the initial explorer window. To access the data, select the desired file type from the “File Type” drop down menu. Figure 6-11, Open File Explorer 6.2.3 Reopen Hovering the cursor over the “Reopen” option opens a side menu containing a list of recently opened documents; open any of the listed documents directly by clicking in the list. The list of recently opened files can be deleted by clicking “Clear Recent List”. NOTE! “Clear Recent List” is an action that cannot be undone. Figure 6-12, Reopen a Previously Open File NOTE! If there are no recent files because the list was cleared or the software is new, the side menu containing recent files will not appear. Page 32 of 161 NOVAtouch™ Operating Manual 6.2.4 SOFTWARE Import The import function imports files for data analysis. The software can upload .qps, .raw, .drf, and .dat files. To change the type of Quantachrome physisorption file select the drop down list for file of type and choose the type of file to import. Figure 6-13 6.2.5 Save The “Save” menu item in the “File” drop down list allows the user to save an open document to its current file name. The menu item is only be available for selection when a change has been made to the document. 6.2.6 Save As The “Save As” menu item allows the user to change the location of a file and the name of a file, but not the file type. 6.2.7 Print The “Print” menu item launches “Print” window from which the selected graph, table, or report file can be printed. This function does not print all open views. 6.2.8 Print Preview The “Print Preview” function displays what will print before executing the process. The preview window includes a zoom function and multi-page display. Figure 6-14, Print Preview Page 33 of 161 NOVAtouch™ Operating Manual SOFTWARE Change User 6.2.9 Clicking on “Change User” opens the “Login” window. Change the User ID by simply editing the field; the name inside the input field will be used as the User ID throughout the software (including printed reports) until the field is updated. Select the “Autologin with this ID” box to set the software to remember the User ID and automatically use it the next time TouchWin™ is started. Figure 6-15, Change User 6.2.10 Exit This closes the program. If there are any edited files still open, and that have not been saved, the user will be prompted to save the necessary files with the changes (click “Yes”), or not (Click “No”… any changes will be lost), before the program is closed. To save the file under a different name before closing the program, click “Cancel” and use the “Save As” function first. Configure The “Configure” drop down menu allows the user to customize most of the software’s appearance, basic parameters, and other settings as detailed below. 6.3.1 Edit Folders The software allows a different predefined default folder settings for each file type it recognizes. Use this configuration window to specify the default location of the selected file type: Figure 6-16 Page 34 of 161 NOVAtouch™ Operating Manual SOFTWARE Selecting “Set Relative” generates this pop-up: Figure 6-17, “Set Relative” Window Selecting “Set Path” launches this window: Figure 6-18, “Set Path” Window Manage Reports 6.3.2 NOTE! A report is a defined collection of tables and graphs intended for printing. The “Manage Reports” function will launch the “Manage Report Templates” window allowing the user to create, import, or modify a report setting. The report settings created using this function will appear as designed in the results, if selected. Add Edit Delete Export Import Page 35 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-19, Manage Report Templates To create a report style using the “Manage Report Templates” window, select the desired report style to edit. Once a field is selected, the “Edit” button will become active. Access the “Edit” function by selecting the desired report to edit and click on the “Edit” button, or by double-clicking the report name. After the file has been edited an asterisk will appear in the “Mod” column to indicate that the file has been altered. To create a new report, use the “Add” button. Enter a new, unique name for the report. The “Report Template Editor” will open to permit changes to the report’s contents/structure. Delete a report by selecting its name from the list, then click the “Delete” button. Use the “Export” and “Import” buttons to save or load an individual report template as a separate file that can be used to share report templates between TouchWin™ installations. Click “OK” to save the changes in this session, or “Cancel” to discard them and return to the main program. The “OK” button is only enabled when changes have been made to the list or any items in it. Page 36 of 161 NOVAtouch™ Operating Manual 6.3.2.1 SOFTWARE Report Template Editor Figure 6-20, Report Template Editor The “Report Template Editor” window is divided into two sections: on the left, the contents of the report template being edited are shown (item type, name, and optional parameter), while on the right side the available items are listed in a hierarchical structure. The user may add only one item at a time to the contents list; to add an item select it from the list on the right hand side, then click “Add”. The contents list allows the user to delete one or more items from the content list in one step by using the “Remove >” button. (Select multiple lines by using either the Ctrl + click, or Shift + click functions). Multiple line selections can only be deleted, they cannot be moved up or down. Individually selected items can be moved up or down using the “Move Up” and “Move Down” buttons below the list. For a graph-type item the “Param” column shows the selected print size of the item (full page, half page, or third of the page). These sizes refer to the printout size of the whole page minus the header. The size can be changed for graph items only. To change the graph size, right click a graph item in the contents menu, and choose the “Set Size” command from the Floating Menu. Figure 6-21, Change Report Graph Size Page 37 of 161 NOVAtouch™ Operating Manual 6.3.3 SOFTWARE Display Properties “Display Properties” expands when hovered over with the cursor to offer “Graph Properties” and “Report Header”. 6.3.3.1 Graph Properties This function allows the user to alter the presentation of each graph type independently by editing the graph’s lines, markers and axes parameters. To edit graphs, first select the document type (Physisorption or Physisorption Overlay) from the drop down menu in the top left corner of the window. To modify a particular graph type click on its name in the selection box. Use the slide bar to access the full list. The highlighted item is the one whose properties are being edited and is represented in the preview (example) graph area. The table in the bottom half of the window lists each of the graph-specific elements and their current settings. Figure 6-22, Graph Properties Page 38 of 161 NOVAtouch™ Operating Manual SOFTWARE Axis Scaling To edit the graph’s x and y-axes click the Properties button to the right of the graphs list. The available scaling modes for both axes are: Auto (0-110%), Auto (tight), and Fixed. Figure 6-23, Graph Parameters Auto (0-110%): The axis values will range from zero to 110% of the maximum data value. If multiple curves are assigned to the axis, the maximum value is calculated from all of those curves. If any of the data values are negative, the scaling will be set to Auto (tight). Auto (tight): The minimum and maximum data values will set the minimum and maximum axis values to -10% and +10% respectively of the span of data values. For example, if the data has values from 50 to 80, the scaling of the axis will be set to 47-83. Fixed: Use the values entered into the corresponding minimum and maximum value fields. Note that this option can leave some (or all) of the data points outside of the visible range. Any changes made will update the preview example. Click “Default” to the left of the preview to revert the axes to the original program values. Graph Line Parameters Use this window to specify the color and marker type for each element displayed on the graph. Select any one ID from the list of graph elements, then click the “Properties” button. In the “Graph Line Parameters” window, select a different color and marker for the chosen element. Page 39 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-24 To alter the color, click “Set” to open the Select Color picker, or enter a web-standard color in the form of #RRGGBB (red/green/blue), or simply type any web-standard color name into the color field! (Notice the color of the text will change to the chosen value). To alter the data point marker, simply select one from the “Marker” drop-down list. When multiple elements are selected, clicking Properties brings up the Color Spread selector. This allows quick assignment of different colors to multiple elements across a range from “Start” to “End” values. The more graph lines that are being edited, the more subtle the color difference between adjacent elements in the list. The Color Spread dialog also allows assignment of the same marker to all graph elements from the Marker drop-down list. Selecting “Leave as is” will ensure the individual elements retain their previously assigned markers. Figure 6-25, Multiple Line Parameters Page 40 of 161 NOVAtouch™ Operating Manual SOFTWARE Click “Default” to the right of the element list to revert colors and markers to the original factory values. Click “OK” to apply all changes made and return to the main program window. Uncheck the Save box if you do not want to make these changes permanent, i.e. they will apply only until the program is closed. 6.3.3.2 Report Header Click to open the “Edit Page Header” window to create a custom header which will print at the top of every page. To add a logo to the header click the “…” button, an explorer window will open; select the appropriate image. Figure 6-26, Edit Page Header NOTE! Re-start the software for the change to take effect. Figure 6-27, Custom Logo and Text in Page Header 6.3.4 Materials The “Materials” item in the “Configure” drop down list, allows the user to modify the model parameters associated with adsorbates (analysis gas) referred to here as “Phys Gas” and model parameters for solids (adsorbents) referred to here as “Phys Adsorbent” and save these changes for later use in data reduction. Page 41 of 161 NOVAtouch™ Operating Manual 6.3.4.1 SOFTWARE Phys Gas parameters NOTE! There are several predefined models (indicated with * in Fig. 6-28) that cannot be changed. Both “Save” and “Delete” buttons are disabled for these gases. Figure 6-28 * * * * Figure 6-28, Predefined Phys Gas Models The user can modify or add new models by importing a file (“Import” button) or changing values to a predefined model. To load a predefined model, click the “Select” button and choose an adsorbate from the side-menu. The current values for each of the parameters is automatically entered into the appropriate fields. To make changes to the model, simply edit the values in the appropriate fields, and click “Save As” (cannot be saved as the same name as the predefined models). Use the “Export” function to save the model as a “.qcPGAS” data file. This file can be used to send the edited adsorbent model via e-mail (or any other means) to another location; it can then be imported (using the “Import” button). To delete an existing model, choose it from the “Select” button, then click “Delete” (predefined models cannot be deleted). NOTE! Once a model is deleted it cannot be brought back. The delete function is irreversible. Click on the “Close” button to leave the window and return to the main program. If there are unsaved changes at this time, the software will prompt to save them before continuing. Page 42 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-29, Editing Adsorbate Gas Parameters 6.3.4.2 Phys Adsorbent Parameters There are three predefined adsorbent models in the TouchWin™ software: Carbon, Oxygen (N2SF), and Oxygen/Zeolite. To modify and save a model see above Sect. 6.3.4.1 Figure 6-30, Setting the Adsorbent Model Parameters Page 43 of 161 NOVAtouch™ Operating Manual 6.3.5 SOFTWARE Phys. Data Reduction Parameters Selecting “Phys. Data Reduction Parameters” from the “Configure” drop down menu will open a window where all of the physisorption data reduction parameters can be edited. If using a specialized gas or application, use this function to create the correct data reduction parameters for the analysis. Once saved, the new data reduction parameters will be available when analyzing data. To load a previously setup profile, select “Load” from the “Phys. Data Reduction Parameters” window. After creating your desired adsorbate model, select “Save” to make the profile available for analytical use. Figure 6-31, Defining the Parameters for an Adsorbate Model 6.3.6 Units of Measurement The “Units of Measurement” option allows the user to change units in which the data are presented. There is not an option to return to previous settings or restore previous selections after changes have been made. The “Use Global” button will return all of the units of measurement to the default values. Page 44 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-32, Units of Measurement Window 6.3.7 Manage Instrument Profiles Selecting “Manage Instrument Profiles” will launch the “Instrument Profiles” window where instrument profiles may be added, edited, or deleted. An instrument profile contains the name and IP address of the instrument and can be loaded when using the “Communication Parameters” option (available on the “NOVAtouch/Instrument Name” drop down menu. See 6.4.3, Communication Parameters). Figure 6-33, Manage Instrument Profiles Window 6.3.8 Control Interface The “Control Interface” option allows the user to select their preferred instrument representation. Either choice (Control Center or Sidebar) will provide the same information: instrument status (Status), analysis information (Analysis), and instrument configuration details (Operation). The software will have to be restarted before any changes to the control interface can take effect. Page 45 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-34, Control Interface Setting 6.3.8.1 Control Center The “Control Center” setting displays all of the instrument’s information (Operation, Status, and Analysis) in a window that can be minimized and therefore will not use space when expanding graphs. Figure 6-35, TouchWin™ Instrument Control Center 6.3.8.2 Sidebar The “Sidebar” setting displays the instrument’s information on the left hand side of the TouchWin™ screen. The Sidebar cannot be minimized, but functions an easy reference point. Figure 6-36, TouchWin™ Sidebar Instrument Name (NOVAtouch) The “Instrument Name” (“NOVAtouch” by default) drop-down menu provides important Page 46 of 161 NOVAtouch™ Operating Manual SOFTWARE resources for connecting to and communicating with the instrument. The title of this drop down menu (i.e. the instrument’s name) is an item that can be edited by changing the “Name” field, or by loading a profile, using the “Communication Parameters” window (see Sect. 6.4.3, Communication Parameters). 6.4.1 Connect Selecting “Connect” from the “Instrument Name” drop down menu will automatically establish TouchWin™ communication with the instrument, if the IP address is properly set. After the instrument is connected, the Sidebar or Control Center will indicate that the instrument is connected (and the option to connect to the instrument will be greyed out). For instructions on how to physically connect to the instrument see Sect. 6.1.3, Instrument – PC Connection. 6.4.2 Disconnect “Disconnect” is only available when the instrument is connected to the TouchWin™ software. Selecting “Disconnect” will cease communication between the software and the instrument until “Connect” is selected again. 6.4.3 Communication Parameters Selecting “Communication Parameters” from the “NOVAtouch/Instrument Name” drop down menu will open the “Edit Profile” window. From the “Edit Profile” window, the instrument name (which will become the title of this drop down menu) and IP address may be set. NOTE! Before connecting to the instrument, coordinate the IP address set on the TouchWin™ software with the IP address set on the NOVA by using the Touch Screen’s “Maintenance Page”. Figure 6-37, Communication Parameters Window Page 47 of 161 NOVAtouch™ Operating Manual NOTE! Changing the name or IP address in the “Edit Profile” window will not create a new profile or permanently create a change to the current profile. To make permanent changes to a profile, use the “Manage Instrument Profiles” item from the “Configure” drop down list. 6.4.4 SOFTWARE Advanced Operations The “Advanced Operations” Floating Menu provides the user with extended access to the instrument firmware. Here, you can view instrument errors, upload analysis data files and instrument logfiles, and upgrade the instrument firmware. 6.4.4.1 View Pending Errors “View Pending Errors” is only available when errors have been recorded. If there are no errors to view this option will be grayed-out/unavailable. Selecting this option will produce a window showing all of the error messages that have been received. NOTE! This symbol will be displayed on the Operation tab of the Control Center or Sidebar when an error has occurred. Errors can only be reported by TouchWin™ if the software is connected to the instrument. 6.4.4.2 Upload from File The “Upload from File” option can only be used if the instrument is connected to the TouchWin™ software. Selecting “Upload from File” will open a window showing all of the files available on the instrument. Select a file by choosing its field, then click “Upload”. After uploading, the file will appear on-screen as well as in the Physisorb (or designated .qcuPhysIso) folder. Figure 6-38, Upload Analysis Results (Field Selected) 6.4.4.3 Upload Logfile Selecting “Upload Logfile” will display the list of instrument logfiles. To upload an instrument logfile, click on its name then click “Upload”. The uploaded file will be saved in the designated Page 48 of 161 NOVAtouch™ Operating Manual SOFTWARE directory; by default a folder named “Instrument Logs”. That is located inside the folder designated for instrument configuration files, (see 6.3.1,”Edit Folders”). Figure 6-39, Upload Instrument Logfile 6.4.4.1 NOTE! To delete any logfiles from the NOVAtouch™’s logfile directory, make the modification at the instrument’s Touch Screen, using the “Maintenance” section. It cannot be modified using TouchWin™. Upgrade Instrument Firmware Selecting “Upgrade Instrument Firmware” launches the “Instrument Firmware Upgrade” window which prompts to select the desired firmware file (.qcUpgrade). When a valid firmware upgrade file has been chosen, the software confirms the selection with the message (in green): “Valid upgrade file. Click Next to start upgrade process.” Follow the instructions on screen until the process is done. NOTE! Only perform the firmware upgrade if instructed to do so by QC Service. When speaking with QC Service be sure to report the software version to ensure compatibility between the software and firmware. Page 49 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-40, Select File for Instrument Firmware Upgrade Figure 6-41, File Selected for Instrument Firmware Upgrade Figure 6-42, End of Instrument Firmware Upgrade Page 50 of 161 NOVAtouch™ Operating Manual 6.4.5 SOFTWARE Backup Instrument Settings The “Backup Instrument Settings” option allows the user to create a file from which instrument parameters can be restored e.g., instrument configuration, calibration values (manifold and transducer), IP address, and cell calibration. It is important to backup your instrument settings before any maintenance occurs and before any firmware upgrades. “Backup Instrument Settings” launches the NOVAtouch™ System Backup window. The software will prompt to enter a unique name, and save the backup file in the .qcNTSysBkp format. Figure 6-43, Start of System Backup Procedure Figure 6-44, Save Backup File Page 51 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-45, Completed System Backup 6.4.5.1 Restore Instrument Settings Selecting “Restore Instrument Settings” opens an explorer window, choose a “.qcNTSysBkp” file to restore the instrument parameters. Figure 6-46, Select File to Restore System 6.4.5.2 Heater Profile Selecting “Heater Profile” from the Instrument drop down menu allows the user to create a Heater Profile using the TouchWin™ software. The “Heater Profile” is used to degas samples on the NOVAtouch™. Use the buttons on the right to add, insert, or edit a line in the heater profile (selecting any of these corresponding buttons will produce the window seen in Figure 6-48. Each line in a heater profile consists of three components: Target (C), Rate (C/min), and Soak Time (min). The instrument will heat the mantle to the target temperature at the rate that is Page 52 of 161 NOVAtouch™ Operating Manual SOFTWARE set then hold the mantle at the target temperature for the set soak time. Selecting “Move Up” will move the selected line up, and similarly, selecting “Move Down” will move the selected line down. “Delete” will remove the selected line from the heating profile. Selecting the “Save” button will save the heating profile as an “.nwOGprm” file. Selecting “Load” will allow the user to open any “.nwOGprm” profiles. Selecting “Send” will upload the profile to the NOVAtouch™ for use. NOTE! “Send” the degas profile to the instrument to start the degassing procedure from the Touch Screen. NOTE! If an existing degas profile is overwritten using the TouchWin software, it needs to be re-loaded ( ) from the Touch Screen before the changes take effect. Figure 6-47, Heater Profile Window Figure 6-48, Edit Heater Profile Option 6.4.6 Analysis Parameters The “Analysis Parameters” window allows the user to setup the common/global parameters for an analysis, as well as, analysis file names and desired analytical points. The Analysis Parameters can be sent to the instrument by selecting “Send” or started from TouchWin ™ by selecting “Start” from the Analysis Parameters window. Page 53 of 161 NOVAtouch™ Operating Manual 6.4.6.1 SOFTWARE Common/Global Analysis Parameters The “Analysis Parameters” contains global parameters which effect every station listed on the “Common” tab. The global parameters include the adsorbate gas, analysis options, P0 options, void volume mode, and evacuation crossover. 6.4.6.1.1 Adsorbate Gas Select a pre-defined adsorbate gas using the selector button. The individual parameters can be overridden by entering custom values here. Check the “Use as Data Reduction Adsorbate Model” box to use your settings as the data reduction adsorbate model. 6.4.6.1.2 P0 Options Specify the method with which the instrument will determine the P0 value for the analysis performed. NOTE! Not all P0 modes are available for all adsorbate gases. Measure: Use the instrument's P0 station to measure the P0 at the beginning of the analysis. Calculate: Automatically calculates a reasonable P0 value from the measured ambient pressure. Daily: Use the instrument's stored Daily P0 value. This method is only recommended when using a stable Dewar in an environment that will not be subject to an atmospheric pressure change greater than 1 mmHg. Continuous: The P0 is measured continuously during analysis at each relative pressure. Depending on the instrument model, a time interval may be used for re-measure timing. Continuous P0 method generally increases analysis time. User: Specify the P0 value (in Torr) to be used. 6.4.6.1.3 Void Volume Mode Specify the method with which the sample cell characteristics are determined for analysis data correction. Helium Measure: Calculates the warm and cold zones by helium expansion. This is the most accurate method, however, time consuming. It is recommended for high accuracy measurements. NOVA Mode: A faster method than the Helium Measurement Mode. The void volume is obtained by measuring the sample volume via the expansion of the adsorbate gas at room temperature using the cell calibrated values of the warm and cold zones. This method does not require He to be installed on the instrument. When using this mode the user will be asked to specify the cell ID at each station. NOVA He Mode: A faster method than the Helium Measurement Mode. The void volume is obtained by measuring the sample volume via the expansion of the He gas at room temperature using the cell calibrated values of the warm and cold zones. This Page 54 of 161 NOVAtouch™ Operating Manual SOFTWARE method is used when the sample has interaction with the adsorbate at room temperature. When using this mode the user will be asked to specify the cell ID at each station. User Entered: Allows the user to specify the cold and warm zone volumes (instead of having the instrument measure them). The User Entered void volume mode is only recommended when same cell and sample are analyzed again, and the user needs to make sure that the coolant level is identical to the analysis that the volumes were initially obtained from. 6.4.6.1.4 Evacuation Crossover Specify the pressure to which the system pumps down using the Fine Vacuum path before opening up to full vacuum (to prevent sample elutriation and contamination of the instrument). The lower this pressure value is set, the greater the time required for evacuating the cell(s) and the slower the analysis will be completed. The following values are available: Pellet: Crossover at 760 Torr Powder: Crossover at 38 Torr Fine Powder: Crossover set to 5 Torr User Entered: Value must be between 5 and 760 Torr 6.4.6.1.5 Analysis Options Fast Init: Instructs the instrument to bypass certain steps during initialization. Bath Thermal Delay: Number of seconds to wait after the coolant Dewar was raised to allow the thermal equilibrium of the immersed cells. Backfill Mode: How to refill the analysis cells after a completed analysis for safe removal. Available options are Helium (requires Helium source), Adsorbate or Vent (ambient air). Page 55 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-49, Analysis Parameters 6.4.6.1.6 Active Stations Check those stations to be analyzed when the analysis is started. At least one station must be selected before an analysis can be started. 6.4.6.2 Analysis Parameters This window contains a Station tab for each station present on the instrument. Each Station tab has four sub-tabs that affect only the analysis at that station: Admin, Points, Analysis, and Reporting. Each sub-tab must be completed prior to starting. NOTE! The fields of each Station sub-tab will remain filled from previous analysis. If there is a change to analysis procedure, address the change by altering the analysis parameter’s station sub-tab. 6.4.6.2.1 Station Admin Tab The “Comment” field can be used to provide further information. The Admin tab however, requires that the “Results File” field be populated. The “Verify” button, scans existing files to ensure that there are no naming conflicts. A unique filename can be generated automatically using a “macro string”. If using a macro, the “Admin” tab will only need to be changed at your discretion (i.e. – when the comment becomes invalid). Page 56 of 161 NOVAtouch™ Operating Manual SOFTWARE 6.4.6.2.2 Results File Macros The software allows the use of special characters as a “filename template” to automatically generate unique filenames for each run. Each macro is in the form of $(CC:prm), in which “CC” is the macro code, and “prm” is an optional parameter field. For example, the format: $(ST)_$(DT:yyMMMdd)_$(TM), will produce the filename “1_15Oct08_111529”, if the analysis was started on Station 1 on October 8th 2015 at 11:15:29”. Page 57 of 161 NOVAtouch™ Operating Manual SOFTWARE Macro for Results File Field $(DT) $(TM) $(SN) $(ST) Date of execution, the formatting strings should be written in the form $(DT:xx), where the x’s are a formatting string value. Time of execution, the formatting strings should be written in the form $(TM:xx), where the x’s are a formatting string value Serial Number Inserts Station ID (1, 2, 3, or 4) Formatting Strings yy Year in 2 digit format yyyy Year in 4 digit format M MM MMM MMMM Month (without leading zero) Month (2 digit, with leading zero) Month name abbreviated (Jan, Feb, etc.) Month name d Day of month (no leading zero) dd Day of month (2 digit, with leading zero) ddd Day of the week abbreviated (Mon, Tue, etc.) dddd Day of the week, full (Monday, Tuesday, etc.) h hour without leading zero hh hour with leading zero H in 24 hr mode, no leading zero HH m mm in 24 hr mode, with leading zero minute (no leading zero) minute (with leading zero) s second (no leading zero) ss second (with leading zero) z millseconds (no leading zero) zzz millseconds (3 digit, with leading zeroes) AP or A AM or PM (hours will be in 12 hour format) ap or a am or pm (hours will be in 12 hour format) Page 58 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-50, Analysis Parameters – Admin Tab 6.4.6.2.3 Station Points Tab The “Points” tab defines the relative pressure, timeout, equilibration, and tolerance for each point in that station’s analysis. The list also contains the tags assigned to each point for use in calculations (e.g., BET, BJH, etc.). The points list is separated into adsorption and desorption branches. Relative pressure values are sorted in increasing order for the adsorption branch points, and decreasing order for desorption branch points. To add individual points, ensure that a branch is selected and click on the “Add” button. In the pop-up window select the desired parameters (multiple points can be added by listing relative pressure values separated by a semicolon (;). Set the Equilibrium parameters as desired, check the data reduction tag boxes, and click “OK”. When points are added to a branch they will be inserted into the existing points list in their proper location with respect to numerical order. In addition the point list will be cleaned up: if any two points are closer to each other than 0.0025 relative pressure one of those will be automatically removed. The point with the higher value will be removed when effecting the adsorption branch and the lower value when effecting the desorption branch. Spreading points allows the user to specify a relative pressure range by means of a point count or relative pressure interval. If using [Spread (by #)] the program will insert the requested number of points, equally spaced within the entered pressure range. When using [(Spread (by dP)] the points will be spaced by the specified delta. For either spread option the starting and ending points of the relative pressure range will be included in the list. To change pre-existing points, select the points to be altered and click on the “Change” button. In the pop-up window select the tag operations (note that each tag value has an ON and an OFF box, tags with none of these selected will be left alone). The tolerance band and the equilibrium times can also be adjusted (if the corresponding box is unchecked they will be left as is). Page 59 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-51, “Change” Pop-up Window To change the tolerance, equilibrium, or timeout, select the check-box to the left of the field. To delete point(s) from the list, select the points and then click the “Delete” button below the list. If a branch node is selected ALL points will be removed from it. Click the “Reset” button to remove all points from the list (both branches). The DoseWizard uses data from a previous run to determine a faster dose routine. Samples must have very similar isotherms in order for the DoseWizard to function properly. The software will prompt for a source file (previous run) to determine the dose routine. Figure 6-52, Analysis Parameters – Points Tab Page 60 of 161 NOVAtouch™ Operating Manual SOFTWARE 6.4.6.2.4 Station Analysis Tab Use the “Analysis” tab to setup the sample cell type. There are three cell sizes: 6 mm, 9 mm, and 12 mm. For each of the cell types there is a “w/rod” and “w/o rod” option; which denotes with and without a filler rod, respectively. It is important to specify the cell type as with or without rod. Choose the cell type from the drop down menu. Figure 6-53, Analysis Parameters – Analysis Tab Figure 6-54, Cell Type Drop Down Menu 6.4.6.2.5 Station Reporting Tab The “Reporting” page allows the user to setup the Data Reduction Parameters and report options for the analysis. Although the “Reporting” page can be ignored, it is beneficial to utilize this tab. Within the Data Reduction Parameters section there is an extensive list of parameters. Because the parameters list is broad the software includes a “Jump to” function. The “Jump to” function will automatically take the user to a location in the list. NOTE! Ensure that the Data Reduction Parameter Set is valid. Failure to do so could result in various software failures and loss of data. Page 61 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-55, Analysis Parameters – Reporting Tab “Reports at end of Analysis” determines how the analysis data is processed after completion. It provides three choices for the final report: “Open”, “Print”, and “Save as text”. NOTE! TouchWin™ must be connected to the instrument during the analysis for the report functions to operate. Figure 6-56, Reports at end of Analysis – “Open” drop down menu To choose a report style, select the desired report format from the “Open” drop down menu. The drop down menu will provide a list of demo files that are provided with the software, as well as any uniquely created report styles. Page 62 of 161 NOVAtouch™ Operating Manual SOFTWARE NOTE! To create a unique report style use the “Report Template Editor” function (see Sect. 6.3.2.1). Figure 6-57, Reports at end of Analysis – “Print” Selection Button To have the data report print at the completion of the analysis, select the check box next to the “Print” field. When “Print” is active a check mark will appear next to the “Print” field (this check mark will disappear when it is inactive). Figure 6-58, Reports at End of Analysis – “Save as text” Drop Down Menu The “Save as text” function saves the data as a text report for later reference. The report will be saved using the style that is chosen from the drop down list. These report options are the same that appear in the “Open” drop down menu. Reports at End of Analysis Options Open Opens the selected report template in a new window. If "— no report —" is selected, no report will be opened upon completion of the analysis. Print Check this box to print the report Save as Text 6.4.7 Select the same or a different report template to be exported into a text file automatically. Cell Calibration Parameters NOTE! Before using the helium free “NOVA” method of analysis, empty cells must be calibrated. Selecting “Cell Calibration Parameters” opens a window with which the basic cell calibration Page 63 of 161 NOVAtouch™ Operating Manual SOFTWARE profile can be setup and started. If the information from the initial Cell Calibration window is sent to the instrument, the Touch Screen will ask for more information at the start of the calibration. The cell calibration can be started from the TouchWin™ program by selecting “Start” in the “Cell Calibration Parameters” window. Figure 6-59, Cell Calibration Parameters Figure 6-60, TouchWin™ Cell Calibration Start Window Window Selecting the “Window” tab will open a menu containing items that allow quick and efficient modification to windows that are open on the software screen. Page 64 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-61, Window Selection Menu 6.5.1 Cascade Selecting “Cascade” will modify the arrangement of all of the open windows and cause them to present one in front of the other in a cascading fashion. Figure 6-62, Cascade Page 65 of 161 NOVAtouch™ Operating Manual 6.5.2 SOFTWARE Tile Selecting “Tile” will arrange all open graphs into an equally spaced format favoring one graph in each corner. Figure 6-63, Tile 6.5.3 Tile Horizontally Selecting “Tile Horizontally” will arrange all open graphs parallel to each other from left to right. Figure 6-64, Tile Horizontally NOTE! “Tile Horizontally” will default to the regular Tile option when more than five graphs are open. Page 66 of 161 NOVAtouch™ Operating Manual 6.5.4 SOFTWARE Tile Vertically Selecting “Tile Vertically” will arrange all of the currently open graphs parallel to each other from top to bottom. NOTE! “Tile Vertically” will default to the regular Tile option when more than three graphs are open. Figure 6-65, Tile Vertically 6.5.5 Close View Selecting “Close View” will close the file that is currently selected (usually the foremost file). 6.5.6 Close All Selecting “Close All” will close all of the windows that are currently open with one action. 6.5.7 Show Sidebar/Control Center This item will be listed as either “Show Sidebar” or “Control Center” depending on which of the two options has been selected from the Configure tabControl Interface. Selecting this item will bring the item (either the sidebar or the control center) into view. NOTE! In order to effect the change between Sidebar and Control Center the program must be closed and re-started. Page 67 of 161 NOVAtouch™ Operating Manual SOFTWARE Help The “Help” menu provides information regarding software use and properties. 6.6.1 Contents Selecting “Contents” from the TouchWin™ “Help” menu launches the “TouchWin™ Help System”. The Help System is a valuable tool as it can answer most questions about software functionality. Figure 6-66, TouchWin™ Help System 6.6.2 About The “About” function launches a window which provides information about the software version and build. If there are ever any matters to be discussed with the Quantachrome Service Department they will ask for the information provided in the about window. NOTE! The instrument F/W (firmware) version is displayed on the Operation tab of the Control Center or Sidebar when the instrument is connected to the software. Figure 6-67, “About” TouchWin™ Page 68 of 161 NOVAtouch™ Operating Manual SOFTWARE TouchWin™ Icon Toolbar The TouchWin™ Icon Toolbar consists of four icons that allow for quick access to frequently requested file management options. Figure 6-68, TouchWin™ Icon Toolbar 6.7.1 Open Selecting the “Open” toolbar icon will launch the Windows file explorer allowing selection of the desired file and opens it in TouchWin™. Figure 6-69, Open File Explorer 6.7.2 Save Selecting the “Save” toolbar icon will save a file as its current name. The type of file being saved will be determined by TouchWin™. 6.7.3 Print Selecting the “Print” toolbar icon launches the Print window allowing selection of: printer, printer preferences, the page range to be printed, and the number of copies to print. Selecting “Print” in this window will print the selected document or report. Page 69 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-70, Print Window 6.7.4 Print Preview Selecting the “Print Preview” toolbar icon will open a window that contains the file and presents the file as it will be printed. Figure 6-71, Print Preview Configuration of TouchWin™-CFR TouchWin™-CFR users have the additional option of operating the software within full compliance of 21 CFR Part 11 guidelines. Consequently, a full audit trail is enabled when utilizing the full security features of TouchWin™. 6.8.1 Initial security configuration After TouchWin™-CFR is installed for the first time, the following screen will appear: Page 70 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-72, CFR Security Configuration Select “Full” Security Level to enable all of the security features including: required login, full audit trail for any changes to data files, the ability to print audits, and software timeout due to user inactivity. NOTE! Select Full Security Level in order for the software to operate within the guidelines of 21 CFR Part 11. Select “Custom” Security Level to choose which security features to incorporate. To enable the security feature, check the box. Selecting “None” will disable all security features. NOTE! Once a given Security Level is selected, it cannot be changed for a given installation. To change the Security Level, uninstall and re-install the software. After the security level has been configured, a Superuser account must be created. Only a Superuser has full control of the system, including defining and managing user accounts. Create the account in the User Account Parameter screen. Page 71 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-73, User Account Parameters If all of the required fields in the User Account Parameters box have been filled in correctly, the OK button will be active. Click the OK button when finished and the Login window will appear. Figure 6-74, Login Window 6.8.2 NOTE! You have three chances to enter a correct User ID and Password combination. The software will automatically disable the User ID’s account if Login is failed three times in succession. If a Superuser’s account is disabled (and this is the only Superuser account for the given installation), the software must be uninstalled and then re-installed. Assigning New Users After login as the Superuser click on Configure SecurityUser Manager. This will open the User Account Manager window. Page 72 of 161 NOVAtouch™ Operating Manual SOFTWARE Figure 6-75, User Account Manager Click “Add” to open the “User Account Parameters” window (below). Enter the required information into the fields provided. Click on Access and select a level from the list. Figure 6-76, Adding a User Account There are three Access levels: Superuser, Manager, and Operator. Superuser — users in this level have full control of the system, including defining and managing user accounts. Manager — users in this level have the same rights as a Superuser except: managing user accounts and deleting points from an existing data file. Operator — users of this level are allowed to operate the software with predefined presets established by a manger or Superuser. The operator can only enter sample information: sample name, sample weight, cell ID, comments, etc. Page 73 of 161 NOVAtouch™ Operating Manual SOFTWARE After creating a new user follow these steps to set the password and allow access for the new user. 1. Restart the software when prompted 2. Login as a Superuser 3. Logout as a Superuser 4. Login as the new user, enter User ID only 5. Enter and confirm new password 6. Click on the OK button 6.8.3 Viewing the System Audit Go to: Configure SecurityView System Audit. This will display the security messages in a window like the one below. Figure 6-77, System Audit Trail NOTE! Only a Superuser can access the System Audit Trail. Page 74 of 161 NOVAtouch™ Operating Manual SOFTWARE Multiple Instrument Control TouchWin™ allows control of multiple instruments from a single PC. Each instrument must be connected to a separate Ethernet port, and the host computer must have sufficient computing power to handle simultaneous communication with all the sources. By default, the software is installed with single instrument control. To set up for multiple-instrument control, the following steps must be taken (outside of the software): 1. Exit TouchWin™ 2. Locate and open in a plain text editor the TouchWin.cfg file (located in the Configuration Root folder of your installation). 3. Locate the value ct=1 in the section [Instances] 4. Change it to the number of instruments to be controlled (the software supports up to 4 instruments). Save and close the file 5. In the Configuration Root folder, create sub-folders named 2, 3 and 4 (one for each instrument). There is already one named "1". 6. Copy the file instrument.cfg from the original sub-folder (1) to each new sub-folder (2-4), and open them in a text editor. 7. Change the item name= (in the section connection) in each sub-folder to a unique name in order to identify the instruments. Save the files. 8. Start TouchWin™. The software will display the unique names of each instrument on the Figure 6-7. Also, the SideBar and/or Control Center have full functionality and are color coded to aid in identifying each instrument. See Below. Figure 6-78, Multiple Instrument Control Displayed Page 75 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN 7 TOUCH SCREEN Please ensure that the NOVAtouch™ is properly installed. The vacuum pump should be connected to the instrument and stainless steel dowels should plug each station. Verify that the gas is connected and turned on with delivery pressure set to 8 psig. Turn on the vacuum pump, lastly, power up the NOVAtouch™. The main screen of the NOVAtouch™ user interface consists of: Side Menu/Tool Box — left side. Containing buttons for selecting operation modes/pages. Page Content — the remainder of the screen. Content depends on the current operation mode. The ten pages are: Home, Manual Mode, Analysis Setup, Cell Calibration, Progress, Degasser, Results Page, Logfile, Tools, and Power (see left). A grayed-out symbol indicates that the page/mode is not available (e.g., manual mode during an analysis). Switch between pages by tapping on the ToolBox buttons. Some operations require an Operator ID to be entered. To enter data into an entry field, simply tap on the field to have the software keyboard appear on the screen. The operator name (in normal mode) is NOT checked against any data. The operator name can be anything except nothing (blank). NOTE! The Operator ID field must be populated. Status Bar The status bar resides along the bottom of each page and displays the current state of the instrument’s operations, each represented by a colored circle (see Figure 7-1, Touch Screen Home Page). In general, a blue circle means “active” and a green circle means “inactive”. A blue circle with a tool symbol inside means that the analysis or degas is setting up and will soon be considered “active”. An orange-filled green circle indicates that a degas station is inactive and that an over-temperature error is the cause of the inactivity. Home The passive Home page displays the status of the instrument hardware: valves, Dewar bath position, pressure reading(s) and temperatures; nothing can be actuated or entered on this page. This page also displays the model type, firmware version and the instrument serial number in the lower left hand corner. Closed valves are colored amber (yellow) and open valves green. Bath position, coolant level and over-temperature appear illuminated when actuated. Page 76 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Manifold temperature and pressure Helium Over-temperature Analysis stations Degassing stations Analysis gases Mantle temperatures Bath position and coolant contact with level sensor Model type, firmware version and instrument serial number Side menu Instrument status bar Figure 7-1, Touch Screen Home Page Manual Mode page The Manual Mode page is visually very similar to the Home page with two distinct differences: (i) there is a “Stop” symbol in the bath control area, and (ii) each valve has a gray switch-bar displayed across it. Tapping the valve symbol reverses the valve’s status and the bar’s orientation, from closed-to-open and vice-versa. Note that the position of the switch-bar displays the last user requested state, and the color of the valve indicates the state of the valve as reported by the firmware. When changing the valves between states there may be a ½-1 second communication delay between changes. The Gas-tank port selection is exclusive, it does not allow more than one gas-port to be selected; opening one gas port will close the other two. All can be closed however by tapping on the open valve. When in manual mode the system does not perform a purge cycle when switching between analysis gases (adsorbates). Page 77 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Tap here to reset the degasser’s over-temperature status if and when the issue that caused the over-temperature condition has been rectified. Tap valve symbol to change its state Click to remain in manual mode (when not locked) Select to lock the unit in Manual mode Figure 7-2, Manual Mode Dewar buttons (UP, Stop, Down (DN)) control the movement of the Dewar. Up/down travel will continue until either the stop symbol is tapped, or the mechanism reaches the travel limit switches. Degas port indicators (located above the degas port numbers) turn bright red if an overtemperature condition exist, in which case power to the affected mantle(s) is terminated. If such an event occurs check the degassing setup (thermocouple connections etc.) to eliminate any safety concerns, then tap the reset button, or press the button above the status indicators on the panel on the right side of the instrument (see Sect. 5.13). If the over-temperature condition still exists the indicator will NOT turn off – this is not a bypass function. Manual mode has a three minute time-out. Without user interaction for three minutes the system will inform the user that the idle time has expired and the user can choose to (i) remain in manual mode (for another three minutes), or (ii) go to the Home page. If no response is given within one minute, the instrument will leave manual mode and return to Home page status. The timer can be disabled by toggling the Lock button (next to the Manual Mode label) allowing the user to stay in manual mode until another mode is selected. Analysis Setup page The Analysis Setup page is used to start an analysis. Each section allows the loading of predesigned analysis/station presets (designed and downloaded to the instrument using TouchWin™ software). To load a preset click on the upload button , and make a selection from the list of presets available. Page 78 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Enter the required parameters by tapping the appropriate entry field invoking the keyboard. The Sample ID field has a pull-down button that allows the user to select a pre-existing Sample ID file created in the degassing section. If there is no pre-existing Sample ID, enter a Sample ID using the keyboard. Each station can be deselected (or re-selected) using the check-box next to its label. Click the Summary button to show a description of the current settings and review the analysis before starting. When viewing the Summary, the lines in red indicate fields that are invalid (or empty) preventing the analysis from initiating. Grayed out lines indicate unavailable or deselected stations. The Clear button will clear all fields –all fields will have to be populated again after clearing the Analysis Setup. The Recall button will bring back the previous entries. The Start button will only be enabled when all data fields are valid and the instrument is in a state where it can accept the command. To start the analysis select Start and the analysis will begin as specified. a clean-up automatically. This may take up 20 minutes depending ituponwilltheperform amount of gas remaining in the sample cell. NOTE! If the instrument needs to establish a safe status due to aborted analysis, suitable coolant and placed on the lift drive in the analysis compartment, with and P cell and level sensor installed (as appropriate) before starting the analysis. NOTE! Samples must be in position at their desired station ports, Dewar filled 0 Page 79 of 161 NOVAtouch™ Operating Manual Select to load the analysis gas. (Note: If the gas port name matches the adsorbate name uploaded, the gas input port will be selected automatically.) TOUCHSCREEN Select to load an analysis parameters preset. (Note: Presets must be created using TouchWin™.) Select to bring back the previous entries. Select to clear the “Analysis Setup” Select to load a station preset. (Note: Presets must be created using TouchWin™.) Select to view a summary of the analysis before starting. Any missing items will be highlighted in red. Select to start the analysis. Figure 7-3, Analysis Setup Page 80 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Figure 7-4, Select Analysis Preset Window Figure 7-5, Select Station Preset Window Cell Calibration page NOTE! A cell calibration is only required if using NOVA mode. The Cell Calibration page is used to start a cell calibration and is necessary when setting up a NOVA mode analysis. The Common Parameters section allows the user to select presets to be used when running the NOVA mode cell calibration. At each of the stations the user must define the station parameters: Cell Type and Cell ID. To overwrite a previously used Cell ID select “Overwrite” at each station. For each station that you would like to run, select the box on the left side of the station. Unselected stations will not run. To load a preset, click on the upload button , and select from the list of presets available. The options along the lower portion of the Cell Calibration page are the same as the options on the lower portion of the Analysis Setup page: The Clear button will clear all of the fields –all Page 81 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN fields will have to be populated after clearing the Analysis Setup. The Recall button will bring back the previous entries; the Summary button will show the current analysis setup. The Start button will only be enabled when all data fields are valid and the instrument is in a state where it can accept the command. Select to launch the list of cell types and choose the correct cell type for the analysis. The Cell ID is entered here. (Note: Only alphanumeric combinations may be used.) Previously created Cell IDs Select to overwrite the Cell ID. Select to start the cell calibration. Select to clear field that is currently activated. Select to fill the fields with the input used in the most recent analysis. Select to view the summary of the analysis setup before starting the run. This display items like the file names and gas settings. It is suggested to always review the analysis summary before starting an analysis. Figure 7-6, Cell Calibration NOTE! It is not necessary to calibrate cells every time a sample is analyzed. NOTE! Calibration is cell specific. NOTE! If cells and filler rods have been calibrated they can be labeled using the white spot at the top of the stem. Labelling cells and filler rods will help prevent future errors. Page 82 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN NOTE! The calibration will be stored in the instrument for future use. Select which stations to run for the calibration by choosing the appropriate boxes. Select to load a parameters preset. (Note: These must be created using TouchWin™.) Select to launch the list of gas ports. Choose the desired gas port from the list that opens. Select to input the P0 value (when using User Entered P0). A list of all of the present calibration IDs. When running a NOVA mode analysis this list will be available for selection. Figure 7-7, Cell Calibration Continued NOTE! Use “Calculate” P0 for adsorbates at their own boiling points. Page 83 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Progress page The Progress page provides up to date information about the state of the instrument during an analysis. The upper left hand corner shows the status of the instrument hardware. The upper right hand corner will show the status of the analysis. And, the lower component of the Progress page shows the instrument logfile. Current status of the instrument Current logfile of the instrument’s activities. Figure 7-8, Progress Page NOTE! The progress page is only accessible during an analysis. NOTE! Along the Status Bar at the bottom of the Touch Screen are colored circles indicating the instrument status. In general, blue means inactive and green means active. Page 84 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Degassing Page The degassing page is used to start the degassing of the samples to prepare them for analysis. The degassing mode (Vacuum* or Flow) is selected on the Degas Page. The mode cannot be changed when one of the stations is loaded. The heater profile must be setup using the TouchWin™ software, then loaded to the station using the Touch Screen. The Sample ID is created at the Degassing Page in this step. When loading a station select and load a Heater Profile using the upload button . Specify Sample ID for each of the ports in the stations that are to be analyzed, if omitted, there will be no sample ID file created. Tap the Preview button to see a tabular representation of the heater profile. Check the box next to Load to include this station on the “Load Selected” operation. When removing a station, select the station to unload and tap “Unload Selected”. NOTE! The degasser can either Load or Unload, but cannot do both at the same time. *NOTE! Vacuum degassing is only available for LX models. Figure 7-9, Degassing Page Results page The Results page will show up to four analysis results (one for each station) at a time. During an analysis the running analysis for each station will be displayed (and automatically updated as Page 85 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN new points are measured). Alternatively, a previously measured data set can be loaded and viewed. At each station the user can click on the “Station” button to maximize/restore the station graph. The following commands can be selected from the “Action>” menu: Upload – force a data retrieval during analysis From File – select and load previous analysis Data The user can select one of the following modes from the top toolbar: Isotherm – Displays the isotherm plot. The “Ads” and “Des” toggle buttons on the plot allow the user to turn the display of adsorption and desorption points off and on. Analysis – Displays analysis information: File name, adsorbate, number of points acquired, P0 mode, time elapsed, total volume, Sample ID, and sample weight. BET – Displays the BET plot. Surface Area – Displays BET surface area calculation results (tabular) including surface area, slope, intercept, correlation coefficient, and C-constant. NOTE! BET calculations are performed on M tagged points (if there are at least 2 of them specified in the analysis point list) OR, if none are tagged, then on all points between 0.05 – 0.3 P/Po. Selecting Action will open a side menu which allows the user to select a data file for viewing. Figure 7-10, Results Page Page 86 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Figure 7-11, Analysis Parameters Figure 7-12, BET Plot Page 87 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Selecting Surface Area will show the BET data reduction results for the selected data. Figure 7-13, Surface Area Data Maintenance page The Maintenance Page provides access to the instruments setups such as gas port assignment, IP address, and system password. The components of the Maintenance Page behave as described below: Figure 7-14, Maintenance Page Page 88 of 161 NOVAtouch™ Operating Manual 7.9.1 TOUCHSCREEN Security When “Security” is selected the user can specify a system passcode (a numeric value) that is required to enter this Configuration window. “Secure Mode” can also be enabled, from which a username/password combination is required for non-trivial operations and allows management of user accounts. Figure 7-15, Security Window 7.9.2 Time Zone Set the time-zone (GMT ± N hours). 7.9.3 Time Selecting “Time” will allow the user to set the instrument’s calendar and clock. To have proper time/time zone combination, always change the time zone first, and then the time. NOTE! Figure 7-16, Time Zone Select Page 89 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Figure 7-17, Date and Time 7.9.4 Language Selecting “Language” drop down will allow the user to select the user interface language from the given options. NOTE! The instrument will have to be restarted before this change can take effect. Figure 7-18, Language Select Page 90 of 161 NOVAtouch™ Operating Manual 7.9.5 TOUCHSCREEN Network Settings Provides access to set the instrument’s network IP address. The instrument IP address must be a unique IP address because this address will be used exclusively for the communication between the instrument and software. Contact your IT department for assistance NOTE! The instrument will have to be restarted before this change can take effect. Figure 7-19, Network Settings 7.9.6 Operation Mode NOTE! The instrument will have to be restarted before this change can take effect. Allows selection of the following options: He tank – He required operations are enabled/disabled depending on the status given to the Helium tank (present or not present). Start new Logfile at analysis start – If selected, will generate a new logfile at the start of every analysis. Purge logfiles after – Select to choose how long the instrument will store the logfiles. The options are as follows: 15 days, 30 days, and Never. NOTE! It is recommended that the “Start new Logfile on analysis start” option is selected. Page 91 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Figure 7-20, Operation Mode 7.9.7 Gas Input Ports Used to assign gas names to each of the three gas input ports, if these exactly match the adsorbate names in TouchWin™ the instrument will automatically use the correct port for the analysis (based upon the analysis parameters). Figure 7-21, Gas Input Ports 7.9.8 Daily P0 This feature measures the P0 and stores the value for later use. Requirements to measure the P0: CLS, P0 cell, and adsorbate gas. The cryogen must be in the Dewar at the analysis station prior to starting a Daily P0 run. To perform a Daily P0, select the correct port for the adsorbate gas, then select “Start”. After “Start” has been selected, the instrument will prompt to verify that a P0 cell and the adsorbate gas are installed. The instrument will go through the process of measuring a Daily Po after “OK” is selected. Page 92 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Figure 7-22, Daily P0 Window 7.9.9 Calibrate Instrument calibration (manifold volume, transducers, etc.) can be accessed by selecting “Calibrate”. To start any of these processes, choose the desired option from the “Operation” drop down menu then select “Start”. The instrument will provide prompts for each process. Figure 7-23, Calibration Window Page 93 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN NOTE! Only perform a pressure transducer calibration if instructed to do so by Quantachrome’s Service Department. Figure 7-24, Transducer Calibration NOTE! Only perform a Leak Test if instructed to do so by Quantachrome’s Service Department. Consult Quantachrome’s Service Department when reviewing your results. Figure 7-25, Leak Test Instrument Part 1 Page 94 of 161 NOVAtouch™ Operating Manual 7.9.10 TOUCHSCREEN File Manager Allows viewing and deleting stored files in the following categories: Analysis Station (Station parameters, points, etc.) Analysis Preset (Analysis Common Data – adsorbate, etc.) Analysis Result Heating Profile Cell Calibration Preset Cell Calibration Data (Cell-IDs) Sample ID – Degas profile applied to a sample Logfiles Logfile The Logfile page shows the instrument record as it is being reported. The logfile is useful for finding the exact actions of the instrument and will be requested by Quantachrome Service Department. The instrument logfile can be uploaded to your personal computer using TouchWin™ software (Instrument Name Advanced Operations Upload Logfile). The uploaded file will typically be stored in “Instrument Logs”. Using default settings, the “Instrument Logs” file can be found by accessing C:\QCdata\TouchWinCfg\1\Instrument Logs. The number (1 in the example given) corresponds to the instrument number created in the instrument’s config file. NOTE! It is recommended that the “Start new Logfile on analysis start” option is checked ON in the Maintenance settings. Tapping the Logfile twice will bring up the instrument control menu allowing the user to adjust the way that the data is presented. The menu options function as described below: Autoscroll – Selecting Autoscroll will cause the instrument to always present the most current line and automatically scroll as the lines build. Deselecting AutoScroll will cause the logfile to stay in one position until the page is moved using the scroll bar on the right side of the page. Show Time – Selecting Show Time will list the date and time next to each line presented. Show Source – Selecting Show Source will list which data type is being shown (Instr, St 1, St 2, St 3, St 4, Degas, Local) next to each line presented. Data Types: Instr, St 1, St 2, St 3, St 4, Degas, Local – Use the check boxes to show/hide specific elements. Page 95 of 161 NOVAtouch™ Operating Manual TOUCHSCREEN Tapping the logfile twice will bring up the logfile control menu. Current logfile of the instrument’s activities. Figure 7-26, Logfile Page Degassing Power Mode Selecting Power Mode opens up a “Select exit operation” window Shutdown — closes the Touch Screen User Interface to prepare the instrument for being powered off using the mains power switch on the side of the unit. When the instrument is powered on again the User Interface will initialize automatically. Restart — reboots the instrument and initializes the User Interface automatically. ! WARNING! Always shutdown using the Touch Screen before switching the unit off at the mains power switch on the left side of the unit. Page 96 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION 8 INSTRUMENT OPERATION Introduction The following sections describe how to prepare and analyze a sample. Please refer to other sections throughout the manual as applicable e.g., for starting an analysis refer to Sections. 7.4 and 8.5 for sample preparation refer to Sections 7.7 and 8.3 . If using the NOVA mode as the void volume method, the sample cells must be calibrated prior to starting an analysis. Cell Calibration 1. Use a cell adapter (with O-ring) and place an empty cell into the NOVAtouch™. Use the cell appropriate to the analysis and mimic the setup exactly (i.e. – if analyzing with a filler rod, calibrate using a filler rod.) 2. Fill a Dewar with liquid nitrogen to the lower tip of the level indicator, and ensure the CLS is installed correctly on the BNC connector. NOTE! It is important to start a NOVA mode analysis with the same level of liquid nitrogen for each analysis. 3. Use TouchWin™ to provide the Cell Calibration Parameters. To access the Cell Calibration Parameters window select the “Instrument” drop down menu, then select “Cell Calibration Parameters”. The cell calibrations can be sent to the instrument by selecting “Send”, allowing the calibration to be started from the Touch Screen (see 7.5 , Cell Calibration). Alternately, the cell calibration may be started from TouchWin™ by selecting “Start” on the “Cell Calibration Parameters” window (see 6.4.7, Cell Calibration Parameters). 4. Enter the Cell ID and Cell Type for each station to be used. rod. NOTE! It must be specified that the cell type has a filler rod or does not have a filler Sample Preparation NOTE! Every sample should be degassed by flow or vacuum before analysis. 8.3.1 Selecting a Sample Cell There are three factors to consider when selecting a sample cell: stem diameter, sample amount/bulb size, and overall length. Stem diameter: Choose the narrowest diameter cell that will comfortably admit the sample. For example, a fine powder should be analyzed in a 6 mm outer diameter (o.d.) (4 mm i.d stem cell). Page 97 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Use the 12 mm o.d. stem cells for large pieces that cannot be reduced in size. Larger particles such as granules, and small pellets might require a 9 mm o.d. (7 mm i.d.) diameter stem. Cohesive powders may be analyzed in 9 or 12 mm stem cells to reduce elutriation and facilitate addition, removal, and cleaning. Sample amount/Bulb size: Always use the smallest bulb that will accommodate the optimal amount of surface area. Larger total surface areas can certainly be analyzed, but they may lengthen the analysis. For surface area determinations only, sample amounts of at least 1 m2 to 5 m2 can be analyzed using nitrogen, but careful consideration should be given to proper degassing and equilibrium criteria. Full adsorption and desorption isotherms should have at least 15 – 20 m2 in the cell. NOTE! Wider stems and larger bulbs can be beneficial in reducing elutriation. Cell length: NOVAtouch™ sample cells are available in two lengths, referred to as “long” and “short”. Use the short CLS (P/N 00080-CLS-S) for short cells (do not mix-and-match long and short cells in the same analysis session). 8.3.2 Methods of Sample Preparation The sections that follow will aid in performing this step correctly. Before NOTE! starting a degassing procedure, the degassing profile will have to be created using TouchWin™ and loaded onto the instrument. (See 8.3.3, Choice of Degassing Temperature and Time, 8.3.4, Elutriation and Its Prevention, and 8.3.5, Programming the NOVAtouch™ .) NOTE! The degasser can only be started using the NOVAtouch ™ Touch Screen. For more information regarding degassing see Sect. 7.7, Degassing, or NOTE! 8.3.5, Programming the NOVAtouch™ NOTE! To calculate the weight of the sample, subtract the empty cell weight from the post degas weight (of both the cell and sample). Page 98 of 161 NOVAtouch™ Operating Manual 8.3.2.1 INSTRUMENT OPERATION Vacuum Degassing Vacuum degas exposes the sample the low pressure of the vacuum pump while it is under heat to remove the impurities that would otherwise prevent a proper analysis. To set-up a vacuum degas on the sample(s) follow the directions below: 1. Weigh an empty cell, add sufficient sample (2-50 m2 total area). 2. Place the sample cell into the heating mantle, then install the cell into the NOVAtouch™ degasser (without filler rods) using the appropriate O-rings and fittings. 3. Once the cell is installed use the hooks located at the top of the degassing compartment to secure the heating mantle. 4. Create a degassing profile in TouchWin™ and send it to the instrument. 5. Ensure that the chosen degassing method is set to vacuum. 6. Start the vacuum degassing procedure at the NOVAtouch™. 7. After degassing is complete, allow the cell to cool. Remove and reweigh the cell to obtain the sample weight. Figure 8-1, Vacuum Degassing 8.3.2.2 Flow Degas Flow Degas directs a flow of gas (attached to the backfill/flow degas input port) over the sample while it is heated to remove impurities. To set-up a flow degas follow the directions below: 1. Install the flow degasser assembly into the degasser station(s) using the 6 mm fittings and O-rings. Because the degasser is split into two stations each with two ports (creating a total of four ports) it is important that the second port associated with a station is plugged with a dowel pin if it is not going to be used during degassing. 2. Place the cell inside of the heating mantle and place the heating mantle into the holder to allow it to sit up right during the degassing process. 3. Insert the metal flow tube into the cell so that the tip of the metal flow tube is close to but does not touch the sample. Use the collar stop to hold the metal flow tube at the appropriate position. 4. Create the degassing profile in TouchWin™ and send it to the instrument. 5. Start the flow degassing procedure at the NOVAtouch™. Ensure that the chosen degassing Page 99 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION method is set to flow. Figure 8-2, Flow Degasser Assembly Figure 8-3, Flow Degassing on the NOVAtouch™ 8.3.3 Choice of Degassing Temperature and Time Samples should be degassed at the highest temperature that will not cause a structural change to the sample (up to 350 °C for standard mantles, or 450 °C if using high temperature mantles). This will accelerate the degassing process. For instance, most carbon samples can also be degassed at 300 °C, as can calcium carbonate. Many hydroxides must be degassed at a lower temperature. Degassing organics must be performed with care since most have quite low softening or glass transition points. For example, magnesium stearate, a common pharmaceutical formulating compound, should be degassed at 40 °C according to USP requirements. Loosely bound water (physisorbed water) will be lost at relatively low temperatures under the influence of vacuum, but strongly bound surface water might require high temperatures. Many zeolites, for example, will retain significant quantities of water in their micropores up to 300 °C or higher. Page 100 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Use technical reference literature such as the Handbook of Chemistry and Physics (CRC, Boca Raton, Florida) and standard methods such as those published by ASTM, DIN, ISO, etc., to guide your selection of an appropriate degassing temperature. If there is access to thermal analysis equipment, especially gravimetric, an analysis should be conducted on a separate aliquot of material prior to degassing on the NOVAtouch™. A suitable degassing temperature lies in a plateau, or weight-stable region, of the thermogram. Ideally, the thermal analysis should be conducted under vacuum. In general, a temperature that is too low will cause lengthy preparation, and may result in lower than expected surface areas and pore volumes. A temperature that is too high can cause irreversible damage to the sample, which can result in a decrease in surface area due to sintering, or an increase in surface area due to a thermally induced decomposition. Time for complete degassing (i.e., complete removal of unwanted vapors and gases adsorbed on the sample surface) can only be properly determined by conducting a series of tests to determine those conditions of temperature and time which yield reproducible data. As a general guideline however, three hours (at temperature) should be considered a reasonable minimum. IUPAC recommend no less than sixteen hours, which can be conveniently achieved overnight. Samples that require low temperatures generally require the longest degas times. However, the USP recommended degassing period for magnesium stearate is just two hours at 40 °C. 8.3.4 Elutriation and Its Prevention Elutriation, or loss of powder out of the sample cell, is caused by too rapid a gas flow out of the cell, and is most problematical when vacuum degassing (since it is easy to regulate the velocity of gas when flow degassing) and analyzing very fine powders. It is particularly challenging for low-density samples, fumed silica for example. Wider stems and larger bulbs can be beneficial in reducing elutriation. Wider stems reduce the velocity of the gas leaving the cell when evacuation begins, thus it is less likely to entrain powder particles and transport them upwards and out of the cell. The presence of a filler rod significantly increases gas velocity because of the narrowing of the internal dimensions and can exacerbate elutriation. In problematical cases, the filler rod may be dispensed with during analysis, but some loss of resolution and/or sensitivity may result. Degassing should always be done without filler rod if possible. The most dramatic elutriation problems are encountered during degassing of damp, “light” powders. As the sample heats from ambient, the pressure over the sample decreases due to the action of the vacuum. At some point the water “flashes” into steam. This rapid expansion of gas volume drives powder out of the bulb and up the stem of the cell. This condition can be reduced or eliminated by (i) pre-drying the samples in a conventional drying oven and degassing under just vacuum or (ii) raising the temperature of the heating mantle in 20 degree steps. It is recommended that the temperature be “paused” at 60 °C for 30 – 60 minutes under vacuum to allow for a milder removal of moisture before increasing the temperature to 80 °C, then 100 °C and finally maximum degas temperature. A further flow restriction in the form of a tight fitting glass fiber filter cartridge called a Nonelutriating plug which can be inserted into the stems of sample cells so long as they don't have hanging filler rods. Non-elutriating plugs are available for 6 mm, 9 mm and 12 mm sample cells. Page 101 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Contact Quantachrome for more information regarding Non-elutriating plugs. In the most difficult cases, and the aforementioned methods have not eliminated the problem it might be necessary to insert a small glass wool plug into the cell stem. This can be held in place between two halves of a cut-in-two glass filler rod. This is the only time that a filler rod should be used in the degasser. 8.3.5 Programming the NOVAtouch™ Degasser 8.3.5.1 Setup To set-up a Degasser temperature profile using TouchWin™ follow the steps below: 1. Open TouchWin™ software, then open the Instrument’s drop down menu from the tool bar. Figure 8-4, Instrument Drop Down Menu 2. Select “Heater Profile” from the drop down menu. The “Heater Profiles” window will open. From this window the user will be able to: create, modify, save, and send heater profiles. A degassing profile can contain a total of six lines, each line is a “step” which must include a ramp rate and target temperature. The soak time is optional. To load a degassing procedure that has been created using TouchWin™, select the “Load” function in the “Heater Profiles” window. Select the desired file from the File Explorer window. Figure 8-5, Creating Degassing Profile 3. To create the heater profile select “Add” on the right hand side of the heater profiles Page 102 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION window. The Add function will request three fields: Target, Rate, and Soak. The “Target” field is the highest targeted temperature of the degassing step. The Target value is in degrees Celsius. The minimum temperature is typically 20 degrees Celsius, depending on the ambient temperature. The maximum temperature is 350 degrees Celsius using standard mantles. Using a set of high temperature mantles and an instrument configured for high temperature degassing, the maximum temperature can be 450 degrees Celsius. The “Rate” field is an expression of how quickly the target temperature will be reached. The Rate field is expressed in degrees Celsius per minute. The software will not allow a rate greater than 90 degrees Celsius per minute. The “Soak” field is the amount of time (in minutes) the degasser will remain at the target temperature. The maximum amount of time that the field will accept is 2400 minutes (40 hours). Figure 8-6, Editing/Creating an Degassing Step 4. To modify the degassing procedure, use any of the tools/functions listed on the right hand side of the Heater Profiles window. Add – Create multi-stepped degassing protocols. The added line will be placed at the bottom of the degassing protocol. It is limited to six line/step protocols. Insert – Using the “Insert” function will add the new line directly above the line that has been selected. Edit – Selecting “Edit” will open the step editor and allows modification of the protocol step’s details: target, rate, and soak. Move Up – Using the “Move Up” function will allow changes to the order of the degassing protocol by moving the selected line up one level. Move Down – Using the “Move Down” function will allow changes to the order of the degassing protocol by moving the selected line down one level. Delete – Using the “Delete” function will remove the selected line from the profile. Page 103 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Figure 8-7, Example of a Completed Degassing Profile Loading the Degassing Profile onto the NOVAtouch™ 8.3.5.2 NOTE! To calculate the weight of the sample, subtract the empty cell weight from the post degas weight (of both the cell and sample). 1. Ensure that the NOVAtouch™ is connected. To connect to the instrument, select the Instrument’s drop down menu from the tool bar, then select “Connect”. 2. Send the Heater Profile to the instrument by selecting “Send” on the lower portion of the Heater Profiles window. 3. At the instrument, select the degassing Page from the Touch Screen side-bar. 4. Use the upload button at either Station 1 or Station 2 to open the desired degassing file. Locate the file in the explorer window when it opens. NOTE! The degassing profile contains temperature information only. The choice of flow (available for all models) or vacuum (LX models only) is done at the instrument Touch Screen via the “Mode” button. Page 104 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Figure 8-8, Send Degassing Profile Figure 8-9, Name Degassing Profile Window Figure 8-10, Degasser Set for Flow Page 105 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION Unloading the Degasser When removing a station, select a station to unload and tap “Unload Selected” (see 7.7 , Degassing Page). NOTE! The degasser can be unloaded during a sample measurement by navigating to the Degassing page on the Touch Screen, selecting a degas station, and selecting “Stop”. Preferably, nitrogen should always be used as flow/backfill gas to prevent or minimize buoyancy errors on weighing. A sample cell will weigh less when filled with helium than when filled with air or nitrogen. The error introduced is approximately 1 mg per mL of cell volume. This can be significant when using extremely small sample weights (< 50 mg). the right side of the instrument at the port labelled “Degas Flow/Backfill”. NOTE! The flow/backfill gas is determined by what is connected to the input on Allow the mantle to cool below 80 °C before unloading the degasser. A sample cell which feels only warm to the touch while still under vacuum can be much hotter to the touch when backfilled with gas. This is particularly true if degassing a large mass of metal sample. Exercise caution! A warm sample cell can also introduce weighing errors. The sample cell should be allowed to cool to room temperature before weighing. If sample throughput permits, cool thoroughly while attached to the NOVAtouch™, otherwise remove and cap the cell, and/or transfer to a desiccator. Start Sample Analysis 8.5.1 Initial Steps at the Start of an Analysis After degassing the sample, follow the initial analysis start procedure below: 1. Verify that the adsorbate gas contains at least 500 PSI in the tank. 2. Fill the Dewar to level indicator, and allow it to settle for 20 minutes, if time allows. 3. Carefully insert filler rods in the sample cells. 4. Install sample cell(s) into the analysis station, taking note of the station number each sample is loaded into. 8.5.2 Starting an Analysis After setting up the analysis using TouchWin™ it can be started directly from a PC or by using the NOVAtouch™ TouchScreen. 8.5.2.1 Starting an Analysis from the TouchScreen Follow the directions below to start an analysis at the TouchScreen (for further information see 7.4 , Analysis Setup): 1. Once an Analysis Preset has been sent to the instrument, select the Analysis Setup page from the Touch Screen’s side menu. 2. On the Analysis Setup page load the preset that was sent to the instrument. Page 106 of 161 NOVAtouch™ Operating Manual INSTRUMENT OPERATION 3. Input the sample weights and sample IDs (or select “Recall” if repeating a sample), and select the adsorbate gas port. 4. At the Touch Screen select Start from the lower right hand corner to begin the analysis. NOTE! Selecting “Recall” will autofill the user entered fields such as sample weight and sample ID, however it will not recall the global analysis preset used or the station presets. Selecting “Recall” should only be done if repeating the same samples and a macro filename has been created (thus ensuring that the previous file will not be written over). 8.5.2.2 Starting an Analysis from TouchWin™ Follow the directions below to start an analysis using the TouchWin™ software (see E. Analysis Parameters for further information): 1. Once the Analysis Parameters window has been completed using TouchWin™, select “Start” to begin the analysis. 2. A second Analysis Parameters window will open; in the new Analysis Parameters window, input: the gas type, sample ID, sample weight, description, and if running a NOVA mode analysis select cell ID. If repeating an analysis, select “Recall” to have the software automatically fill in all of the sample information. NOTE! If using NOVA mode samples should be analyzed within the same cell used when creating the cell calibration, and if applicable, using the same filler rod. NOTE! Samples must be in position at their desired station ports, Dewar filled with suitable coolant and placed on the lift drive, and P0 cell and level sensor installed before starting the analysis. Page 107 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ 9 DATA ANALYSIS USING TouchWin™ In addition to providing PC control over the measurements, TouchWin™ is also a comprehensive program for enhanced data analysis. TouchWin™ provides features such as graphical plots, alternative theoretical models, external data archiving, and editing capabilities. Opening Data Files To start using the TouchWin™ software for data analysis, first open the desired data file. To open a data file, click the “Open Folder Icon” on the Main menu bar or click “Open” on the “File” menu. By default, TouchWin™ stores the data files in the “Physisorb” folder. Figure 9-1, Physisorb Folder Where Data Files are Stored Select a file and click “Open”. Alternatively, to reopen recent files click “Reopen” on the “File” menu or click the “Reopen Folder Icon” on the Main menu bar. Additionally, TouchWin™ software allows opening any known data file by simply draggingand-dropping a file from Windows® Explorer into the TouchWin™ main window. Multiple files can be opened this way. 9.1.1 Selecting File Type The TouchWin™ software supports three file extensions: .qcuPhysIso, .qcuPhyOverlay and .qcuPhHoa. Click on the drop down button (left of the “File name” field) to display the supported documents and to view the selected file type. Page 108 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Figure 9-2, Selecting type of file to open Below is a list of file types that can be used with TouchWin™ software. Table 9-1, File Types Used with TouchWin™ NOVAtouch™ File Instrument Extension Access QC PhysiSorption NovaTouch™ .qcuPhysIso Open Physi Overlay NovaTouch™ .qcuPhOverlay New/Open Isosteric Heats of Adsorption NovaTouch™ .qcuPhHoa New/Open Legacy Files Instrument Extension Access Quantachrome.qps Autosorb, Quadrasorb, NOVAe, Hydrosorb, Aquadyne, .qps Import Autosorb.RAW Autosorb-1/6 .raw Import .drf Import .dat Import Autosorb.DRF NOVA.DAT 9.1.2 [P/Po, volume] Autosorb-1/6 [P, Po, vol., time] NOVA [P/Po, volume] NOTE Any legacy file type that has been imported can be saved as a QC PhysiSorption file type. Data Processing Warnings When opening a data file that has relative pressures (P/P0) greater than 1.0 or that has nonmonotonic points (points that do not increase in volume with increasing pressure) a warning is displayed, see below. Data reduction is not prevented, however, some processing may not function properly on these data files. Page 109 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Figure 9-3, Warning about possible problems with data For data with relative pressures greater than one, the P0 should be checked for validity. For nonmonotonic data, the offending points may be deleted and the data saved to a new file for processing. Usually the non-monotonic points are at very low pressures where little adsorption has taken place and signal is in the noise range of the transducers. Deleting these points does not affect the integrity of the data. If non-monotonic points occur at higher pressures (>0.1 P/P0) the data should be questioned and rerun if possible. Floating Menu The Floating Menu is the main tool used to obtain data results. To use the contextual Floating Menu and obtain data results, right-click on a graph or table to access the reporting options. Tables, Graphs and Reports Figure 9-4, Floating Menu for Graphs, Tables, and Reports Page 110 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ NOTE! The list of report options will reflect the reports that have been setup, and the quantity of options in the Floating Menu will grow accordingly. Editing Analysis Data Information To confirm or change (where allowed) analysis-related information in the data file, right-click on any graph or table and select “Edit Analysis Data” from the Floating Menu: The resulting “Analysis Header” window contains all of the metadata and information that is displayed in the header of each page of the report – including those which cannot be changed. If a parameter that is used for calculating results (reduced data) is changed, such as the sample weight, the affected results will be recalculated when “OK” is selected. Clicking “Cancel” will disregard any changes made in this window. NOTE! Attempting to close an edited data file without saving it, the software will prompt to save the data before the file closes. If you do not wish to overwrite the original information, click cancel and use the “Save As” function (with a new, unique filename) before closing the file. Any changes to the file, including any to the “Analysis Data” will be lost if the file is closed without using “Save” or “Save As”. Setting Data Reduction Tags Some calculations rely on specific data points to be identified: those to be used (“tagged”) and those to ignored or excluded (“untagged”). To reveal the point tags for a given data file, rightclick on an open plot or a table associated with this file to access the Floating menu, then click “Edit Data Tags” to open the tag editor window: Figure 9-4, Set Data Tags Page 111 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Refer to the “Tags” column immediately to the right of “Vol” to review which tags are currently set for each point. The A and D tags cannot be altered since they indicate to which branch of the isotherm they belong (Adsorption and Desorption respectively) as originally measured. The ON/OFF/RESET area to the right serves as both legend and tag selector. Refer to Sect. 9.6 , for guidelines regarding the appropriate relative NOTE! pressure ranges for each calculation. NOTE! Not all available calculations use tags (e.g. DFT). To make changes to points, follow the steps below: 1. To select points: click on a single point to select it (clicking on a different point automatically deselects the first), Ctrl-click to add/remove a single point, Shift-click to select range from last clicked item, or use the “Select All” or “Select None” buttons at the bottom left of the Edit Data Tags window. 2. Using the selector boxes, apply tags to the selected points: a. Check a box next to the tag to add (turn ON) or remove (turn OFF) it from the points listed. Unchecked tags will be left in their current state. b. To make the changes to the point(s) tag(s), click “Apply to Selected”. c. Use the “Reset” button to deselect all tag checkboxes. The “Reset” button does not revert the tag selections to a prior instance. 3. To delete one or more points from the data set: a. Highlight one or more points as above b. Click “Delete” to remove the points permanently. 4. To ignore or accept the changes made: a. Click “Cancel” to discard all changes and return to the open file in the main program. b. Click “OK” to accept the changes and return to the open file in the main program. All affected calculations will be re-evaluated, and results displayed in the open tables and/or graphs results will be automatically updated. NOTE! ‘P’ tags below P/P0 = 0.35 can be automatically ignored (as they should be*) by making the appropriate selection in the Data Reduction parameters dialog. *The option to use P tags below P/P0=0.35 is provided to allow comparison with other pore size calculations, such as DFT. Page 112 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Setting Data Reduction Parameters. Physical sample parameters on which calculations rely, and other computation options are accessed via the “Data Reduction Parameters” (DRP) in the Floating Menu: Figure 9-5, Data Reduction Parameters Dialog 1. Scroll down to a particular group of settings, or use the “Quick Jump” drop-down menu for faster navigation. 2. To apply changes to the data, click “Save” to store the settings in a Physisorption Data Reduction Parameters (*.drp) file. The files should be stored in the program’s “TouchWinCfg”. It is recommended that you do not overwrite the pre-programmed “default” file, but use a unique and descriptive filename. 3. Click “Load” to select a *.drp file previously created and update the data reduction parameters. 4. To ignore or accept the changes made: a. Click “Cancel” to discard all changes and return to the open file in the main program. b. Click “OK” to accept the changes and return to the open file in the main program. All affected calculations will be re-evaluated, and results displayed in the open tables and/or graphs results will be automatically updated. NOTE! Results to be included in The Area/Volume Summary report are defined in the Data Reduction Parameters window. Page 113 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ The table below provides a general guide for the Tag selection and gives the pressure ranges in which various calculation models are applicable. Table 9-2, Gas Sorption Calculation Methods P/P0 Range Calculation Model 10-7 – 1 NLDFT, QSDFT, GCMC 0.0001 – 0.1 DR, DA < 0.15 HK, SF 0.05 – 0.3 (Classical BET) range) BET Micropore BET assistant BET for microporous samples (Rouqerol point selection method) > 0.15 t-plot, alpha-s, FHH, DFT > 0.35 BJH, DH, Fractal–FHH, NK Calculation of Heats of Adsorption For the calculation the isosteric heat of adsorption on a sample from physisorption data, measure at least two, preferably three, isotherms at different temperatures. To perform the calculation go to: New on the File menu and click Isosteric Heats of Adsorption. This will open the Heats of Adsorption window. Click Add to open and add an isotherm file to the set of isotherms to use for the calculation of Heats of Adsorption. It is recommended to add the lowest temperature isotherm first. Add at least two isotherms and click OK to perform the calculations and display the results. Review of the Data Analysis Methods Before referring to specific calculation methods, check the Adsorbate and Adsorbent settings in Data Reduction Parameters, to verify that the correct gas and surface chemistry are selected for the measurement data. Calculation “tags” are required for some of the calculations to identify the data points used. Right click in the graph or table to bring up the Floating Menu, then click “Edit data Tags”. For calculations that do not use tags, their settings are accessed in Data Reduction Parameters. Some calculations (e.g. t-plot, BJH) require both tags and selections within Data Reduction Parameters. The requirements for each calculation are outlined below. 9.2.1 BET: Multipoint Tags : M DRP : Adsorbate (cross sectional area) Page 114 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ To calculate the Multi-point BET surface area for the sample, set the appropriate data points with the M tag. The multi-point BET surface area calculation requires a linear plot of 1/ [W (P0/P)–1] vs. P/P0, which for most solids using nitrogen as the adsorbate is restricted to a limited region of the adsorption isotherm. For nonporous and mesoporous materials this is usually in the P/P0 range of 0.05 to 0.35, however, this linear region is shifted to lower relative pressures for microporous materials. The standard multipoint BET procedure requires a minimum of three points (preferably five) in the appropriate relative pressure range. If the Y-intercept is negative and/or the points clearly do not fall on a straight line, the point range should be adjusted as described below. Once the desired range is selected, click “OK” to set M-tags to all adsorption points within the highlighted range or “Cancel” to return without making any changes. 9.2.1.1 The BET Assistant (Rouquerol method) The BET equation is certainly applicable to macro- and mesoporous solids, but, in a strict sense, it is not applicable to microporous adsorbents. The type of porosity (i.e. macro-, meso-, or micropores) plays an important role in the applicability of the BET equation, notwithstanding the problems arising from the chemical and geometrical heterogeneity of a surface. The Micropore BET Assistant [161] helps the user select points within the linear range of the BET equation. To access the Micropore BET Assistant, select “Edit Data Tags” in the Floating menu, then click on the “Micropore BET Assistant” button. The “Micropore BET Assistant” window will display a plot of P/P0 vs. V(1–(P/P0)) and the recommended range for the BET equation. The software will automatically select the range of pressures to use, but it is possible to override the automatic selection by dragging the sliders below the graph to move the boundaries of the BET region. Once the desired range is selected, click “OK” to set M-tags to all adsorption points within the highlighted range or “Cancel” to return without making any changes. 9.2.1.1.1 User Actions Menu “Unzoom”: reverts to the unzoomed display. “Enter Values”: Pressure range boundaries can be set by entering the Start (lowest value) and End (highest value) limits. “Recommended”: reverts to the original recommended values. “Currently Tagged”: reverts to the range defined by the M-tags set prior to entering the BET Assistant. 9.2.2 BET: Single point Tags : S DRP : Adsorbate (cross sectional area) Use the S tag (usually at P/P0 = 0.3) to calculate the value for the Single-point BET. Page 115 of 161 NOVAtouch™ Operating Manual 9.2.3 DATA ANALYSIS - TouchWin™ NOTE! The single point BET calculation is not limited to just one datum point. Langmuir Surface Area Tags : L DRP : Adsorbate (cross sectional area) To calculate the Langmuir surface area for the sample, set the appropriate data points with the L tag. 9.2.4 t-plot: Statistical Thickness Methods Tags : T DRP : Model type For the t-plot method calculations, T tags must be set for the desired data points. Note that the Carbon Black t-method calculation corresponds to ASTM D6556. 9.2.5 Total Pore Volume Tags : V DRP : Adsorbate (liquid density) The Total Pore Volume calculation can be found in the Tabular Data (“Tables” portion of the software). Assign the V tag to the desired datum point (usually the last adsorption datum point in the isotherm, i.e. at the highest P/P0, or a point on the plateau-region of the isotherm). NOTE! Only one V-tag. 9.2.6 Average Pore Size Tags : V, M DRP : Adsorbate (liquid density) The Average Pore Size calculation can be found in the Tabular Data (“Tables” portion of the software). The Average Pore Size calculation requires the calculation of the Multi-point BET surface area (M tags) in addition to the V tag. 9.2.7 Tags DRP BJH: Barrett, Joyner & Halenda Method, DH: Dollimore Heal Method :P : Thickness Calculations, moving average, ignore points below P/P0 = 0.35. Scroll or jump to the BJH/DH/Kr87 section of the “Data Reduction Parameters” window to Page 116 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ access parameters for these methods. The BJH and DH methods can be used to calculate pore size distribution plots and tables for the adsorption and/or desorption branches of the isotherm. Tag the appropriate adsorption and/or desorption data points with the P tag. This calculation uses the statistical thickness of the adsorbed layer of the adsorbate on the surface of the sample; choose a t-method calculation method (de Boer, Carbon Black, Halsey, or Generalized Halsey) to use in the BJH and/or DH calculations (but do not use the T tags for these calculations). The moving point average determines the number of adjacent, calculated pore size points (averaged across a moving window) to smooth the calculated pore size distribution; it does not smooth the original isotherm data points. Set this value to 1 to include all of the P-tagged data points in the calculation without any smoothing. Check “Ignore P tags below 0.35 P/Po” to exclude these points from the calculation. To set interpolation ranges for the BJH/DH method calculations, click “Add” to fill in the desired ranges in the fields provided. Click “OK” or “Cancel” to close the “Data Reduction Parameters” window. 9.2.8 SF and HK: Saito Foley Method and Horvath Kawazoe Method Tags : None DRP : Tabular Data Interval Scroll to the “SF and HK Calculations” section of the “Data Reduction Parameters” window to access parameters for these methods. The “Tabular Data Interval” is the number of data points that will be displayed on the data tables. For example, to tabulate every other data point a value of 2 should be entered for the Tabulated Data Interval. 9.2.9 NOTE! The NOVAtouch™ does not have the hardware features required to acquire the data necessary to employ the SF and HK, however, a file from an ASiQ can be uploaded to the software to employ the SF and HK methods. DR: Dubinin Radushkevich Method Tags : R DRP : β, n Use the DR method set R Tags for the desired P/P0 points in the measurement and enter the Affinity Coefficient (β). The value of the DR exponent (n) can be adjusted in the “Adsorbent” section of the “Data Reduction Parameters” window. See Section 10.3.3 for more information on the DR method. 9.2.10 DA: Dubinin Astakhov Method Tags : R DRP : E, n, K For the “DA Method” enter initial values for the E and n parameters and the appropriate Page 117 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Interaction constant (K) for the adsorbate used. See Section 10.3.4. 9.2.11 MP Method Tags : None DRP : Thickness interval Select the MP section on the Data Reduction Parameters window to access the Thickness interval parameter. The MP method does not require any other data tags. Enter the Thickness interval value in its field. 9.2.12 Tags DRP Alpha-s Method :T : Model type For the alpha-s method calculations, T tags must be set for the desired data points. Select a Standard Isotherm File from the pull-down list in Data Reduction Parameters: Alpha-S Calculations, see below. Then select the desired P/P0 value for the calculation. alpha–s Standard Isotherm File Material / Experimental Conditions _asilar _asil1 _acarb _aalum1 Nonporous hydroxylated silica (argon at 77K) Nonporous hydroxylated silica (nitrogen at 77K) Nonporous carbon (nitrogen at 77K) Nonporous alumina (nitrogen at 77K) 9.2.13 Fractal Dimension Methods FHH: Frenkel-Halsey-Hill / NK: Neimark Kiselev Methods Tags : R DRP : N/A These two methods, Frenkel-Halsey-Hill (FHH) and Neimark Kiselev (NK) evaluate the Fractal Dimension, D. They are intended for investigation using data acquired in the micropore region (below a relative pressure of 1x10-3). Both of these methods can be used for the adsorption and/or desorption branches of the isotherm. Assign R tags to the desired data points. 9.2.14 Tags DRP Kr(87) Thin Film Pore Size Method (Data Reduction Only) :P : moving average, ignore points below P/P0 = 0.35 This is a novel method for the pore size analysis of thin porous (siliceous, oxidic) films by krypton adsorption at 87 K according to the method suggested by Thommes et al. [40]. NOTE! The NOVAtouch™ does not have the hardware features required to acquire the data necessary to employ the Kr(87) Thin Film Pore Size method. Page 118 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ see Powder Tech Note 39, available analysis, representative or qc.support@Quantachrome.com. NOTE! For additional information about using Krypton for thin film pore size from your local Quantachrome In the primary application range of this method, that is, a pore diameter range between ca. 2.5 nm and 8 nm, the obtained pore size data are traceable to NLDFT pore size data (please see Sect.10.4 for more information). The wider application range of this Kr-87 K/thin film method extends from ca. 0.7 nm to up to 8 nm). In order to apply this data reduction method on Kr/87 K adsorption isotherm data (as measured on a capable instrument, for example, Autosorb-iQ-MP). 1. Import the data file in the TouchWin™ software. 2. Select Krypton@87 as the adsorbate in Data Reduction Parameters. The file header will not read Krypton@87K stated as the analysis gas/Adsorbate automatically. To change it, right click to access the Floating Menu, click “Edit Analysis Data” and edit the field labeled “Adsorbate Name”. 3. Apply "P tags" to the adsorption data points to include them in the pore size distribution (please note that the method is not applicable to desorption data). Make sure not to include data from potential bulk sublimation transition (indicated by a steep step in the isotherm close to or at the saturation pressure). 4. Select Kr(87) Thin-film method (graph or table) from the Floating menu. NOTE! A moving point average smoothing is applied to the data. The moving point average size is set from the BJH/DH/Kr87 section of the “Data Reduction Parameters” window. 9.2.15 Area-Volume Summary Tags : individual methods included must have tags set DRP : individual methods included must have data reduction parameters set/options selected Selecting “Tables > Area-Volume Summary” from the Floating Menu generates a tabular summary consisting of the data header information plus area and volume results calculated from the selected models. To select the calculations to include in the Area-Volume Summary, open the “Data Reduction Parameters” window, using the QuickJump or scroll bar go to the “Area/Volume Summary” section; check/uncheck those that apply. Be sure to set all the required parameters for the selected methods. Data Presentation The TouchWin™ software is also used to generate graphical and tabular reports of experimental data, and calculated results for viewing and report generation (the data file must have the appropriate parameters i.e., specific data point tags and the necessary calculation parameters. See 9.6 Setting Data Reduction Parameters.). Tables and plots generated for a given data file can be Page 119 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ accessed from the contextual Floating Menu. To view the list of available graphs or tables, right click on the graph to open the Floating Menu then click “Graphs” or “Tables”. This will open the respective submenu to select the particular item to access. In some cases this item is listed on a lower level submenu. If a plot or a table is selected and the data reduction parameters and/or the appropriate tags for the calculation are not set properly, the software will display an error message. When viewing a plot or table with the results of calculations obtained by a given method, the user can change the number of data points or P/P0 data range (“Data Reduction Parameters “P0 Override”) via the Floating Menu. To modify data tags for a given data file, right-click on an open graph/table to activate the Floating Menu. Click “Edit Data Tags” on this menu to add or remove appropriate tags in this window. Click “OK” when finished. This will automatically update all the open plots and tables related to the modified data. 9.3.1 Configuring Graph Properties To modify the features of the graphs, go to the Configure tab, Display Properties Graph Properties. Graph properties can be set for every plot that is generated by the software. Each plot may have different settings such as x and y axis values, data point marker style, graph colors, and line thickness. To set values for a specific plot locate the method in the list on the left side of the “Graph Properties” window. The selected (active) item will be highlighted. operate the Graph Properties. NOTE! See: Sect. 6.3.3.1, Graph Properties for more information about how to To access this window: Go to: Configure tab, Display Properties Graph Properties. Or, click “Graph Properties” on the Floating Menu. Page 120 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ Figure 9-6, Graph Properties Click the “Save” checkbox before hitting “OK” to store the current settings to permanent storage, to use these settings for all future graphs. If the user does not save the settings they will be lost when the program is closed. Click “OK” to return to the main window of the program, and apply all changes made. Click “Cancel” to discard all changes made in this window. 9.3.2 Creating Overlay Plots NOTE! An Id must be given to all plots in the overlay. See: Sect. 6.2.1 The TouchWin™ software allows the user to construct overlay plots containing different data files. To create a new overlay, select “File New Physisorption Overlay”. This will open the explorer window prompting to choose a root file. Additional plots may be added to overlay atop the root file by right-clicking on the root plot and accessing the overlay plot’s Floating Menu. Right-click on the plot and select “Manage Isotherms” to access the “Overlay Manager” window. Click “Add” and select an appropriate file from the list, click “Open”. When prompted, enter the display label for the added data, click “OK” to view the overlay graph. Alternately, an overlay root file can be made from any of the plots available in the software. To make a file into a root file, right-click on the plot to overlay additional data files and select “Create Overlay” from the Floating Menu. The user will be required to input a file name for the overlay plot file (.qcuPhOverlay) before the overlay plot opens. After inputting the file name and selecting “Save” an overlay plot with the name that has been designated will open automatically. To change the graph properties, right-click on the graph, then click “Graph Properties” to open Page 121 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ the window. To access and modify the Data Reduction Parameters for the overlay plot, select a file from the “Overlay Manger” window then select “Edit Data Reduction Parameters”. To change the label or description of a file, select the file from the list in the “Overlay Manager” window and click “Edit Description”. To remove a file from the graph select it on the list and click “Remove”. To save the overlay graph click “Save As” in the “File” menu. The graph will be saved under a new name with the .qcuPhOverlay file type in the Physisorb Data folder. Figure 9-7, Overlay Manager 9.3.3 Generating Custom Reports NOTE! See also: Sect.6.3.2, Manage Reports. To generate custom reports, go to the “Configure” tab and click “Mange Reports”. This activates the “Manage Report Templates” window. The files listed in this window were saved during the software installation. The list includes sample report files (titled “demo.XXX”) which may be used or edited. To modify an existing report file, highlight the file name and click “Edit”. The user may also create their own report file by clicking the “Add” button. A window will appear prompting to enter a filename for the report. Enter the filename then click “OK”. The “Report Template Editor” window will appear. To remove unwanted report file, highlight its name and click “Delete”. NOTE! Deleting a report file is an irreversible action. Once a report file has been deleted, it cannot be retrieved. Choose the desired combination of graphs, tables, and metadata (data reduction parameters and calculation method summaries). These report items are listed in a hierarchical view grouped as Page 122 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ follows: Graph — available graph items further grouped by the calculation methods Tables — tabular data lists (grouped by calculation method) MetaData — additional text data. Including calculation result summaries, data reduction parameters and analysis parameters Formatting — insert a page break into the report Figure 9-8, Report Template Editor Highlight a selection and click “Add”, the selections will appear in the left-hand space. To change the printing order for the report, highlight the selection and click the “Move Up” or “Move Down” buttons. For graphs, select the size of the printed selection by right-clicking on the “Param” field and selecting “Set Page Size” from the Floating Menu. Available choices are “Page”, “Half Page”, and “1/3 Page”. Note that these sizes refer to the printout size of the whole page minus the header. Click “Remove” from the field’s Floating Menu, or “Remove >”, to remove the selection from the report. Use the “OK” button to accept the changes, or the “Cancel” button to discard them. NOTE! Tables do not have page size settings in the Report Manager. The custom report can be assigned to a data file before the analysis, by requesting the report to be automatically printed at the completion of the analysis. To assign the custom report to the open data file, activate the contextual Floating menu by right clicking on the opened file, click “Reports”, then click the appropriate report on the submenu. When a report is assigned to the data file, all graphs, tables, and metadata (data reduction parameters and calculation method summaries) will be produced by the software. Page 123 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ NOTE! Make sure that the necessary data reduction tags have been correctly assigned to the models that will be contained in the report. If this is not done prior to selecting the report, an error message will appear prompting to add the required data reduction tags. 9.3.4 Saving Tables as Text Any table can be saved as text. Right click on the table and select “Save as text” from the Floating Menu. This will open the “Save as text to…” window with Exports as default folder. These text files can be imported into a spreadsheet and used in other programs for further display and analysis. Alternatively “Export to .CSV” can be selected. This will open the “Save text as…” window with Physisorb as the default folder. CSV files are text files with a list of data values separated by commas. Figure 9-9, Saving Tables as Text 9.3.5 Changing Header Information The following is an example of a report header: Figure 9-10, Report Header Page 124 of 161 NOVAtouch™ Operating Manual DATA ANALYSIS - TouchWin™ To change the information at the top of the header that is displayed on-screen and on each printed page of the report, go to “Configure Display Properties”, then click “Report Header” on the submenu. Enter the header in the “Line” fields (3 lines max), add a custom logo if desired, and click “OK” when finished. When the new text is added Quantachrome information will remain in this portion of the Header. Click “OK” to save changes. Page 125 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION 10 THEORY AND DISCUSSION NOTE! While the NOVAtouch™ instrument is not equipped to perform N2/77K adsorption analysis below a relative pressure of 1 x 10-3, its associated PC software, TouchWin™, is capable of performing data reduction on such data acquired on other instruments that are very-low pressure capable. This section contains an overview of the theories on which the physisorption methods of analysis and characterization are based. It is intended to give the reader a basic understanding of adsorption chemistry and how it is used to characterize powders and porous materials. It is not intended to be a comprehensive treatise on the subject. Further, while the software is capable of performing the calculation, the NOVAtouch™ cannot provide the necessary data for pressures below 10-3 relative pressure. For a more in-depth treatment of the subject, the reader is referred to “Characterization of Porous Solids and Powders: Surface Area, Pore Size, and Density” [40]. Surface Area The Brunauer-Emmett-Teller [1] (BET) method is the most widely used procedure for the determination of the surface area of solid materials and involves the use of the following equation: 1 𝑃 𝑊 (( 𝑃𝑜 ) − 1) = 1 𝐶−1 𝑃 + ( ) 𝑊𝑚 𝐶 (𝑊𝑚 𝐶) 𝑃𝑜 (1). where W is the weight of gas adsorbed at a relative pressure, P/Po, and Wm is the weight of adsorbate constituting a monolayer of surface coverage. The term C, the so-called BET C “constant”, is related to the energy of adsorption in the first adsorbed layer and consequently its value is an indication of the magnitude or strength of the adsorbent/adsorbate interactions. 10.1.1 Multipoint BET Method The BET equation ( 1) requires a linear plot of 1/[W(Po/P)-1] vs. P/Po which for most solids, using nitrogen as the adsorbate, is restricted to a limited region of the adsorption isotherm, usually in the P/Po range of 0.05 to 0.35; this linear region being shifted to lower relative pressure values for microporous materials. A typical BET plot is shown in Figure 10-1. Page 126 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION Figure 10-1, Typical BET Plot The standard multipoint BET procedure requires a minimum of three points in the appropriate relative pressure range. The weight of a monolayer of adsorbate Wm can then be obtained from the slope s and intercept i of the BET plot. From equation (1): 𝑠= 𝐶−1 𝑊𝑚 𝐶 (2). 𝑖= 1 𝑊𝑚 𝐶 (3). and Thus, the weight of a monolayer, Wm, can be obtained by combining equations (2) and (3): 𝑊𝑚 = 1 𝑠+𝑖 (4). The second step in the application of the BET method is the calculation of the surface area. This requires knowledge of the molecular cross-sectional area Acs of the adsorbate molecule. The total surface area of the sample, St, can be expressed as: 𝑆𝑡 = 𝑊𝑚 𝑁𝐴𝑐𝑠 𝑀 (5). where N is Avogadro’s number (6.0221415 × 1023molecules/mol) and M is the molar mass (molecular weight) of the adsorbate. Nitrogen is the most widely used gas for surface area determinations since it exhibits intermediate values for the C constant (50–250) on most solid surfaces, precluding either localized adsorption or behavior as a two dimensional gas. Since it has been established [2,3] that the C constant influences the value of the cross-sectional area of an adsorbate, the acceptable range of C constants for nitrogen makes it possible to calculate its cross-sectional area from its bulk liquid properties. For the hexagonal close-packed nitrogen monolayer at 77 K, the accepted cross-sectional area Acs Page 127 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION for nitrogen is 16.2 Å2. The specific surface area S of the solid can be calculated from the total surface area St and the sample weight ws, according to equation (6): 𝑆= 10.1.2 𝑆𝑡 𝑤𝑠 (6). Single Point BET Method For routine measurements of surface areas, a simplified procedure may be applied, using only a single point on the adsorption isotherm in the linear region of the BET plot. For nitrogen, the C-value is often sufficiently large to warrant the assumption that the intercept in the BET equation is zero. Thus, the BET equation (1) reduces to: 𝑊𝑚 = 𝑊(1 − 𝑃⁄𝑃𝑜 ) (7). By measuring the amount of nitrogen adsorbed at one relative pressure (preferably near P/Po = 0.3) the monolayer capacity, Wm, can be estimated using and the total surface area, St, can then be obtained in the similar way to (5), that is: 𝑆𝑡 = 10.1.3 𝑊𝑁𝐴𝑐𝑠 𝑃 (1 − ) 𝑀 𝑃𝑜 (8). Multipoint/Single Point Comparison The relative error introduced by the single point versus the multipoint method for determining surface area is a function of the BET C constant and the relative pressure used. The magnitude of the error in the single point method can be determined from a comparison of the monolayer weight obtained from the BET equation (1) and the single-point equation(7). Solving equation (1) for Wm gives: 𝑃𝑜 1 1 𝑃 𝑊𝑚 = 𝑊 ( − 1) + 𝐶 − ( ) 𝑃 𝐶 𝐶 𝑃𝑜 (9). Rewriting the single point equation (7), and where W’m denotes the single point value, gives: 𝑃𝑜 𝑃 𝑊𝑚′ = 𝑊 ( − 1) ( ) 𝑃 𝑃𝑜 (10). The relative error inherent in the single point method, then, is: 𝑃 1 − (𝑃 ) 𝑊𝑚 − 𝑊𝑚′ 𝑜 = 𝑊 𝑃 𝑊𝑚 1 + [𝑃 (𝐶 − 1)] (11). 𝑜 Equation (12) indicates that for a given C value, the relative error decreases with increasing Page 128 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION relative pressure. Therefore, a relative pressure as high as possible, yet still in the linear region of the BET plot, should be chosen for single point surface area determinations. For all except microporous samples a P/Po of about 0.3 is preferable. For single point determinations on microporous samples a relative pressure as high as possible on the linear BET plot should be chosen. 𝑠 𝐶 =( )+1 𝑖 (12). Table 10-1 gives the relative error for various C values calculated from equation (13) using P/Po of 0.3. For example, when the C constant is 100, a two percent error is indicated. Table 10-1 Single Point/ Multipoint Comparison C Relative Error 1 0.70 10 0.19 50 0.04 100 0.02 1000 0.002 ∞ 0 Prior to using the single point method for the determination of surface area, the C constant can be evaluated from a multipoint BET plot. That is, where s and i are the slope and y-intercept, respectively, of the BET plot. Subsequently, the single point method can be used on materials having the same composition. For greater accuracy, if the C constant is known, the single point result may be corrected using equation (12). 10.1.4 Langmuir Method In the absence of meso and/or macropores, a sample containing micropores will exhibit a Type I, sometimes referred to as a Langmuir isotherm (see Sect. 10.2.1). The Langmuir equation (13) is a limiting case of the BET equation (1) i.e. the adsorption of a single molecular layer of adsorbate: 𝑃 𝐶 (𝑃 ) 𝑊 𝑜 = 𝑊𝑚 1 + 𝐶 ( 𝑃 ) 𝑃 (13). 𝑜 W and Wm are the weight of adsorbate at some P/Po and the weight in a monolayer, respectively. C is a constant associated with the energy of adsorption. Equation (13), rewritten in the form of Page 129 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION a straight line: 𝑃 (𝑃 ) 𝑃 (𝑃 ) 1 = + 𝑜 𝑊 𝐶𝑊𝑚 𝑊𝑚 (14). 𝑜 allows the determination of the slope (1/Wm) from a plot of (P/Po)/W versus P/Po. The weight of a monolayer Wm may then be used to calculate the total surface area of the sample from equation (5). This method is not always applicable to composite materials containing micropores and meso- and/or macropores. In any case, the limiting uptake of gas by a microporous solid is not necessarily due to the formation of a monolayer, but rather a micropore volume filling limit, and the calculated surface area can be significantly in error. Pore Size by Gas Adsorption It is expedient to characterize pores according to their sizes: • Pores with openings exceeding 50nm in diameter are called “macropores”. • The term “micropores” describes pores with diameters not exceeding 2nm. • Pores of between 2-50nm are called “mesopores”, and to classify them according to their geometry (shape). 10.2.1 Isotherms The classification of isotherm shapes is useful in understanding the pore structure of the solid under investigation. IUPAC’s updated proposals by Thommes et al. [45] are briefly described below. In the case of physical adsorption, sorption isotherms obtained on microporous materials are often of (reversible) Type I. The micropore filling and therefore high uptakes are observed at relatively low pressures, because of the narrow pore width and the high adsorption potential. The limiting uptake (plateau) being governed by the accessible micropore volume rather than by the internal surface area. Type II sorption isotherms are typically obtained in case of non-porous or macroporous adsorbent, where unrestricted monolayer-multilayer adsorption can occur. The inflection point or knee of the isotherm (“point B”) indicates the stage at which monolayer coverage is complete and multilayer adsorption begins. The reversible Type III isotherm has no point B indicating that the attractive adsorbateadsorbent interactions are relatively weak but that the adsorbate-adsorbate interactions play the most important role. Isotherms of this type are not common. Type IV isotherms are typical for mesoporous materials, the most characteristic feature of Type IV(a) being the hysteresis loop which is associated with the occurrence of pore condensation. Limited uptake over a range of high P/P0 (a plateau) indicates complete pore filling. Type IV(b) without hysteresis is associated with a mesopore network of narrow width below a critical diameter (which depends on both adsorbate and temperature) and by conical mesopores closed at the tapered end. The initial part of the Type IV can be attributed to Page 130 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION Amount Adsorbed monolayer-multilayer adsorption as in case of the Type II isotherm. Relative Pressure (P/P0) Figure 10-2, IUPAC Classification of Sorption Isotherms [45] Type V isotherms exhibit pore condensation and hysteresis. However, in contrast to Type IV the initial part of this sorption isotherm is related to adsorption isotherms of Type III, indicating relatively weak attractive interactions between the adsorbent and the adsorbate. The Type VI isotherm is a special case, which represents stepwise multilayer adsorption on a uniform, non-porous surface [42], particularly by spherically symmetrical, non-polar adsorptives. The sharpness of the steps depends on the homogeneity of the adsorbent surface, the adsorptive, and the temperature. Furthermore, it is widely accepted that there is a correlation between the shape of the hysteresis loop and pore network effects and fluid metastability giving rise to delayed condensation and evaporation. Briefly, type H1 is found in materials which exhibit a narrow range of uniform mesopores. As such, pore network effects are minimal and the steep, narrow loop is indicative of delayed condensation on the adsorption branch. The “triangular” hysteresis loops of type H2 are given by more complex pore structures in which network effects are important. The characteristic very steep desorption branch can be attributed either to pore-blocking/percolation in a narrow range of pore necks or to cavitation-induced evaporation. Type H2(b) is also associated with pore blocking, but the size distribution of neck widths is much larger. Page 131 of 161 NOVAtouch™ Operating Manual Amount Adsorbed THEORY AND DISCUSSION Relative Pressure (P/P0) Figure 10-3, Hysteresis Types Type H3 has two distinctive features: (i) the adsorption branch resembles a Type II isotherm, and (ii) the lower limit of the loop is normally located at the P/P0-limiting cavitation behavior. These isotherms are typically produced by (non-rigid) aggregates of plate-like particles, but also if the pore network consists of macropores that are not completely filled with condensate. H4 is somewhat similar, with the adsorption branch being a composite Type I / Type II, the more pronounced uptake at low P/P0, compared to H3, being associated with the filling of micropores in mixed micro-mesoporous systems. Distinctive type H5 is associated with certain pore structures containing both open and partially blocked mesopores. The common feature of H3, H4 and H5 is the sharp step down in desorption where the loop closes. Generally, this is located in a narrow range of P/P0 for the particular adsorptive and temperature (e.g., at P/P0 ∼ 0.4 – 0.5 for nitrogen at 77 K). These hysteresis loops impose a difficulty on the pore size analysis… should the adsorption or desorption branch be taken for calculation of the pore size distribution curve? The answer depends very much on the reason(s) which caused the hysteresis. 10.2.2 Total Pore Volume and Average Pore Radius The total pore volume is derived from the amount of vapor adsorbed at a relative pressure close to unity, by assuming that the pores are then filled with liquid adsorbate. For a discussion of the relationship between pore size and relative pressure, see Sect. 10.3.2. If the solid contains no macropores, the isotherm will remain nearly horizontal over a range of P/P0 values approaching unity. In this case, the limiting adsorption can be identified reliably with the total pore volume. However, in the presence of macropores the isotherm rises rapidly near P/P0 = 1 and, in the limit Page 132 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION of large macropores, can exhibit an essentially vertical rise and so it is not practical to evaluate the data in terms of a true total pore volume. Nevertheless, a summed – or cumulative – pore volume of all pores smaller than a certain size (as corresponds to the point on the isotherm chosen for the calculation) can be determined. The volume of nitrogen adsorbed (Vads) can be converted to the volume of liquid nitrogen (Vliq) contained in the pores using equation (15). That is, 𝑉𝑙𝑖𝑞 = 𝑃𝑎 𝑉𝑎𝑑𝑠 𝑉𝑚 𝑅𝑇 (15). in which Pa and T are ambient pressure and temperature respectively, and Vm is the molar volume of the liquid adsorbate (34.76 cm3/mol for nitrogen at 77.4K). Alternatively, 𝑉𝑙𝑖𝑞 = 𝑉𝑎𝑑𝑠 𝑀𝑊 ∙ 𝑉𝑀′ 𝜌 (16). where 𝑉𝑀′ is the molar volume of gas (22,414 cm3 at STP), MW is the molecular weight (mass) of the gas (N2 = 28.0134), and ρ is the density of liquid adsorbate at the temperature of the analysis (0.806 g/cm3 for nitrogen at 77.4K). The average pore size can then be estimated from the pore volume. For example, assuming cylindrical pore geometry (Type H1 hysteresis), the average pore radius rp is expressed by: 𝑟𝑝 = 2𝑉𝑙𝑖𝑞 𝑆 (17). where Vliq is obtained from equation (15) and S is the BET surface area. For other pore geometries knowledge of the shape of the hysteresis in the adsorption/desorption isotherm is required. 10.2.3 Pore Size Distributions (Mesopore) The distribution of pore volume with respect to pore size is called a pore size distribution. It is generally accepted that the desorption branch of the isotherm is more appropriate than the adsorption isotherm for evaluating the pore size distribution of an adsorbent. Data points on the desorption branch of the isotherm, corresponding to the same volume of gas as adsorption points, occur at lower relative pressures, i.e. at a lower free energy state. Thus, the desorption isotherm is closer to true thermodynamic equilibrium. However, in certain cases, samples exhibiting Type H2 hysteresis for example, the adsorption isotherm is recommended for pore size distribution determinations. TouchWin™ software has the capability to use either branch of the isotherm for the calculation. Since nitrogen has been used extensively in gas adsorption studies, it has been well characterized and serves as the most common adsorbate for pore size distribution measurements. Therefore, the following discussion will apply to the use of nitrogen as the adsorbate. Historically, mesopore size calculations are made assuming cylindrical pore geometry starting Page 133 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION with the Kelvin equation (18) in the form 𝑟𝐾 = −2𝛾𝑉𝑚 𝑃 𝑅𝑇𝑙𝑛 (𝑃 ) 𝑜 (18). where: γ = the surface tension of nitrogen at its boiling point (8.85 ergs/cm2 at 77 K). Vm = the molar volume of liquid nitrogen (34.7 cm3/mol). R = gas constant (8.314x107 ergs/deg/mol). T = boiling point of nitrogen (77 K). P/P0 = relative pressure of nitrogen. rK = the Kelvin radius of the pore. Using the appropriate constants for nitrogen, equation (18) reduces to 𝑟𝐾 (Å) = 4.15 𝑃 𝑙𝑜𝑔 (𝑃 ) 𝑜 (19). The Kelvin radius rK is the radius of the pore in which condensation occurs at a relative pressure of P/Po. However, prior to condensation some adsorption has already taken place on the walls of the pore and so rK does not represent the actual pore radius. Conversely, during desorption an adsorbed layer remains on the walls when evaporation occurs. The actual pore radius rp is given by: 𝑟𝑝 = 𝑟𝐾 + 𝑡 (20). where t is the thickness of that adsorbed layer. An empirical method for estimating t was proposed by de Boer [6] in the form of equation (21) and is also used for pore size distribution calculations in the TouchWin™ software. 0.5 13.99 𝑡(Å) = [ ] 𝑃𝑜 𝑙𝑜𝑔 ( 𝑃 ) + 0.034 (21). Other expressions for t calculations, available through the TouchWin™ software, are presented in the Section 10-3. TouchWin™ computes the pore size distribution using the methods proposed by Barrett, Joyner, and Halenda [7] (BJH) and by Dollimore and Heal [8] (DH) as described in the following sections. Page 134 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION 10.2.3.1 BJH Method Using the starting point for the calculation, relative pressure (P/P0)1 close to unity, we can assume all pores (of interest) are filled with liquid. The largest pore of radius rp1 has a physically adsorbed layer of nitrogen molecules of thickness t1. Inside this thickness is an inner capillary with radius rK from which evaporation takes place as P/P0 is lowered. The relationship between the pore volume Vp1 and the inner capillary (Kelvin) volume VK is given by: 2 (22). 2 V p1 = V K1 r p1 / r K1 When the relative pressure is lowered from (P/P0)1 to (P/P0)2 a volume V1 will desorb from the surface. This liquid volume V1 represents not only emptying of the largest pore of its condensate but also a reduction in the thickness of its physically adsorbed layer by an amount Δt1. Across this relative pressure decrement the average change in thickness is Δt1/2. The pore volume of the largest pore may now be expressed as: V p1 r p1 = V 1 r K1 + t 1 / 2 (23). 2 When the relative pressure is again lowered to (P/P0)3 the volume of liquid desorbed includes not only the condensate from the next larger size pores but also the volume from a second thinning of the physically adsorbed layer left behind in the pores of the largest size. The volume Vp2 desorbed from pores of the smaller size is given by: V p2 r p2 = r K2 + t 2 / 2 2 V 2 - V t 2 (24). An expression for VΔt2 is: V t 2 = t 2 Ac1 (25). where Ac1 is the area exposed by the previously emptied pores from which the physically adsorbed gas is desorbed. Equation (26) can be generalized to represent any step of a stepwise desorption by writing it in the form: 𝑛−1 (26). 𝑉∆𝑡𝑛 = ∆𝑡𝑛 ∑ 𝐴𝑐𝑗 𝑗=1 The summation in the equation above is the sum of the average area in unfilled pores down to, but not including, the pore that was emptied in the desorption. Substituting the general value for VΔt2 into equation (24) results in an exact expression for calculating pore volumes at various relative pressures. Page 135 of 161 NOVAtouch™ Operating Manual V pn THEORY AND DISCUSSION r pn = r Kn + t n / 2 2 V n - t n n -1 j=1 Ac j (27). Since the exposed area (Ac) for any given emptied pore is not a constant but varies with each decrement of P/P0, due to thinning of the adsorbed layer; this term must be evaluated. However, the true area of each pore Ap is a constant and can be calculated from the pore volume, assuming cylindrical pore geometry. That is: 𝐴𝑃 = 2𝑉𝑃 𝑟𝑃 (28). Then the pore areas can be cumulatively summed so that for any step in the desorption process Ap is known. The BJH method offers a means of computing ∑Acj from Ap for each relative pressure decrement. It is assumed that all pores emptied of their condensate during a relative pressure decrement have an average radius 𝑟̅𝑐 calculated from the Kelvin equation (18) radii at the upper and lower values of P/Po in the desorption step. The average capillary (core) radius is expressed as: 𝑟̅𝑐 = 𝑟̅𝑃 − 𝑡𝑟̅ (29). Where 𝑡𝑟̅ is the thickness of the adsorbed layer at the average radius in the interval in the current pressure decrement and is calculated from equation (21). The term “c” in equation (26) then is given by: r - tr c = rc = p rp rp (30). Equation (27) now can be used in conjunction with equation (30) as an exact expression for the computation of pore size distributions. 10.2.3.2 DH Method A computationally simpler approach to evaluating mesopore size distributions was developed by Dollimore and Heal [8]. The DH approach differs from the BJH method in that the term Vt is calculated from: n 𝑉∆𝑡𝑛 = ∆𝑡𝑛 Σ𝐴𝑃 − 2𝜋𝑡𝑛 ∆𝑡𝑛 Σ𝐿𝑃 (31). where, the summations ΣAp and ΣLp represent the areas and lengths, respectively, of all the pores emptied of condensate in previous desorption steps. Assuming cylindrical pore geometry, the cumulative pore areas and lengths can be estimated for each desorption step by summing the expressions: Page 136 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION 2𝑉𝑃 𝑟𝑃 (32). 𝐴𝑃 2𝜋𝑟𝑃 (33). 𝐴𝑃 = and 𝐿𝑃 = respectively. Micropore Analysis Several different approaches to micropore analysis are available using TouchWin™. While no single treatment is applicable to all situations, enough flexibility is provided for the user to select the analysis most suitable for a given situation or material. 10.3.1 V-t Method The TouchWin™ software can use any of the t-methods of Halsey [9] the generally preferred one of deBoer [10] and the STSA (carbon black) model [11] for the determination of micropore volume in the presence of mesopores. This method involves the measurement of nitrogen adsorbed by the sample at various pressure values. The procedure is the effectively the same as that employed in the BET surface area measurement, but it extends that pressure range to moderately higher pressures to permit calculation of the “external” surface area (external to micropores that is), that is, the non-microporous part of the material (which includes the contribution to total area by mesopores and macropores as well as the outermost convex particle surface). A t-plot is simply a graphical plot of the volume of gas adsorbed versus t, the statistical thickness of an adsorbed film, for each P/P0 datum point used in the calculation In the TouchWin™ software, the t values are calculated as a function of P/P0 using either the de Boer equation: 0.5 (34). 13.99 𝑡(Å) = [ ] 𝑃 𝑙𝑜𝑔 ( 𝑃𝑜 ) + 0.034 the Carbon Black equation: 𝑃 2 𝑃 Å 𝑡( ) = 0.88 ( ) + 6.45 ( ) + 2.98 𝑃𝑜 𝑃𝑜 (35). or the Halsey equation which, for nitrogen adsorption at 77 K can be expressed as: 𝑡(Å) = 3.54 [ 5 1⁄ 3 (36). ] 𝑃 2.303 𝑙𝑜𝑔 ( 𝑃𝑜 ) Page 137 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION or in a generalized Halsey form (found useful for other adsorbates and/or temperatures) as: 1 𝑡(Å) = 𝑎 [ ] 𝑃𝑜 𝑙𝑛 ( 𝑃 ) 1⁄ 𝑏 (37). Where the pre-exponential term, a, and the exponential term, b, are 6.0533 and 3.0 for nitrogen adsorption at 77 K, respectively. Typical t-plots are shown in Figure 10-4, Figure 10-5, and Figure 10-6 below, representing various possible pore sizes. First t-plot of a sample having no micropores, as evidenced by the ability to extrapolate the line to the origin, since the slope represents the total surface area St of all the pores, that is: 𝑆𝑡 = 𝑆𝑇𝑃 𝑉𝑎𝑑𝑠 ∙ 15.47 𝑡(Å) (38). VADS (STP) 𝑆𝑇𝑃 where 𝑉𝑎𝑑𝑠 is the volume of gas adsorbed, corrected to standard conditions of temperature and pressure, and the constant 15.47 represents the conversion of the gas volume to liquid volume. Thickness (Å) Figure 10-4, t-Plot of a Mesoporous Materia Page 138 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION Thickness (Å) VADS (STP) Figure 10-5, t-Plot of a Microporous Sample Thickness (Å) Figure 10-6, t-Plot of a microporous material Using the slope, s, of the t-plot (as shown) above, equation (36) reduces to: 𝑆𝑡 (𝑚2 ⁄𝑔) = 𝑠 ∙ 15.47 (39). In the absence of micropores, there is good agreement between the t-area, St, and the surface area determined by the BET method. When micropores are present, the t-plot will exhibit a positive intercept. t-Plots for two types of microporous materials are shown in Figure 10-5 and Figure 10Page 139 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION 6. Figure 10-5 is a t-plot of a sample with pore openings smaller than 7–8 Å in diameter. Quantitative pore volume data from t-plots cannot be obtained below t = 3.5 Å, corresponding to pores smaller than 7 Å wide, since this t value represents the diameter of a nitrogen molecule. The intercept, i, in the t-plot, when converted to a liquid volume, gives the micropore volume, VMP, that is: 𝑉𝑀𝑃 = 𝑖 ∙ 1.547 × 10−3 (40). The two linear regions of the t-plot in Figure 10-6 indicate the presence of micropores larger than 7Å and the actual pore width (2t) can be estimated at the position where the two linear plots intersect. The slope of the upper linear portion (B) of the t-plot in Figure 10-6 gives the mesopore surface area using equation (34), while the slope of the lower linear portion (A) represents the total surface area of all pores. Point C indicates the presence of micropores of about 10Å width (2t). 𝑆𝑀𝑃 = 𝑆𝐵𝐸𝑇 − 𝑆𝑡−𝑝𝑙𝑜𝑡 (41). The linear BET region for microporous materials generally occurs at relative pressures less than 0.1. The linear t-plot range will be found at higher relative pressures and is dependent on the size distribution of micropores. The micropore surface area, SMP, is the difference between the BET surface area and the external surface area St-plot from the t-plot. 10.3.2 Alpha-s (αs) Method An empirical analogue to the t-method was proposed by Sing [12], who pointed out that comparing a given isotherm to a standard curve does not require invoking the concept of a statistical thickness, t (which in turn depends on the BET surface area of nonporous reference materials), see equation (138). Instead, similar trends and conclusions to those derivable from tplot figures can be reached by replacing the BET area as a normalization factor by the amount adsorbed at some arbitrarily chosen relative pressure, usually P/P0 = 0.4. Therefore, the Alpha-s method in principle allows a more direct comparison between actual and nonporous reference isotherms. In practice, complications arise because the Alpha-s method is found to depend on the exact nature of the material chosen as nonporous reference. Nonetheless, the Alpha-s method (by analogy with the t-method) has found use for the determination of micropore volumes by extrapolation of Alpha-s curves to αs = 0, and for the determination of nonporous surface area contributions (from the slopes of linear portions of Alpha-s curves, since the ratio of actual to reference BET surface areas is equal to the ratio of actual to reference slopes in these Alpha-s plot regions), by qualitative comparison of actual isotherms with judiciously selected reference isotherms 10.3.3 MP Method An extension of de Boer’s t-method for micropore analysis was proposed by Mikhail, Brunauer, and Bodor [13]. This MP method uses the fact that t can be calculated independently of the solid by: Page 140 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION 𝑡(Å) = 104 ∙ 𝑉𝑙𝑖𝑞 𝑆𝐵𝐸𝑇 (42). A Vliq vs. t plot is constructed from t vs. P/Po data for a sample with a similar BET C value, as shown in Figure 10-7 below, using linear slopes constructed for t-value intervals from the origin to 4 Å, 4 to 4.5 Å. 4.5 to 5 Å, etc. Using the equation above, micropore surface areas can be calculated from the slopes and each successive interval calculation represents the area of all the micropores remaining unfilled. The calculations are continued until no further decrease in slope is found in the V vs. t plot, indicating that all the micropores have been filled. The surface area of pores in the range of thickness from 4 to 4.5 Å, for example, is the difference between the values calculated from the first and second slopes. The area of pores in the thickness range from 4.5 to 5 Å is the difference between the values calculated from the second and third slopes, and so on. Pore volumes can similarly be calculated, using the relation V = 10-4 S 1 - S 2 t1 +2 t 2 cm3 g -1 (43). Where: S1 = surface area calculated from slope 1 S2 = surface area calculated from slope 2 t1 = thickness at beginning of interval used for slope 2 t2 = thickness at end of interval used for slope 2 Each succeeding group of pores is correspondingly treated, and a distribution of pore volume is thus obtained. While the exact pore shape is usually unknown, cylindrical pores are generally assumed. It has been shown that this pore volume relation is equally valid for cylindrical pores or parallel plates. Page 141 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION Figure 10-7, Typical V vs. t-Plot with Internal Slopes 10.3.4 Dubinin-Radushkevich (DR) Method Based on the Polanyi potential theory of adsorption [14] Dubinin and Radushkevich [15] postulated that the fraction of the adsorption volume V occupied by liquid adsorbate at various adsorption potentials can be expressed as a Gaussian function: 𝐴 2 𝑉 = 𝑉0 𝑒𝑥𝑝 [− ( ) ] 𝛽𝐸0 (44). where A is the free energy of adsorption, which in the early Dubinin’s works was called adsorption potential 𝑃𝑜 𝐴 = 𝜀 = 𝑅𝑇𝑙𝑛 ( ) 𝑃 (45). In equation (42) V0 represents micropore volume, E0 is the so-called characteristic energy of adsorption and β is the affinity coefficient which can be approximated [16] by a ratio of the liquid molar volumes v of a given adsorbate and benzene used as the reference liquid: 𝛽= 𝑣 𝑣𝐶6 𝐻6 (46). Equation (42) can be written in the following linear form: 𝑅𝑇 2 𝑃𝑜 2 (𝑉 ) 𝑙𝑜𝑔10 𝑉 = 𝑙𝑜𝑔10 0 − 2.303 ( ) 𝑙𝑜𝑔10 ( ) 𝛽𝐸0 𝑃 (47). which shows that micropore volume V0 and E0 parameter can be calculated from the linear fit of the isotherm data plotted as log(V) vs. [log(P0/P)]2. Intercept of the fitted straight line gives Page 142 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION log(V0) while its slope m can be used to calculate E0. (48). 2.303 ∙ 𝑅𝑇 𝐸0 = √ 𝑚𝛽 The linear range for these plots is usually found at relative pressures of less than 10-2. Based on empirical studies Dubinin and Stoeckli proposed [17] that E0 can be related to the characteristic micropore width, PW, for a carbonaceous adsorbent by the following simple formula 26(𝑘𝐽 𝑛𝑚 𝑚𝑜𝑙 −1 ) 𝑃𝑊 = 𝐸0 (49). The linear form of the DR equation was also used by Kaganer [18] to evaluate micropore surface area from the plot intercept, log(V0), by applying equation (5). log W = log(W0 ) - m log K P0 P (50). 2 Where: W = weight adsorbed at P W0 = total weight adsorbed m =slope of straight line K = Pc T P0 T c 2 Pc = critical pressure of adsorbate (mm Hg) Po = saturated vapor pressure of adsorbate (mm Hg) T = adsorption temperature (K) Tc = critical temperature of adsorbate (K) Other modifications [19] of the DR method include: a) Allowing the DR exponent, n, to differ from n=2 in order to provide a better data fit for non-Gaussian pore size distributions, see next section; and b) Introduction of a supercritical adsorption constant, K, into equation (45) Equation (48) has been proposed as a valid correlation for adsorption data at temperatures exceeding the critical temperature of the adsorbate. 10.3.5 Dubinin-Astakhov (DA) Method For a large number of microporous materials, the adsorption isotherm can be well characterized by the Dubinin-Radushkevich equation. However, for those microporous materials with Page 143 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION heterogeneous distributions or strongly activated carbons, the Dubinin-Radushkevich equation fails to linearize the adsorption data [20]. To describe adsorption on wider range of microporous materials the Dubinin-Astakhov equation was proposed: - RT ln P / P0 n W = W 0 exp - E (51). where: W = weight adsorbed at P/Po and T W0 = total weight adsorbed E = characteristic energy n = non-integer value (typically between 1 and 3) Whereas, equation (50) is a generalized form of the Dubinin-Radushkevich equation (n=2) and has been found to fit adsorption data for heterogeneous micropores [21]. The Dubinin-Astakhov equation requires the parameters n and E to be calculated re-iteratively by non-linear curve fitting to the adsorption isotherm in the low relative pressure, micropore region. The values of n and E obtained are then used in equation (50), [22]: d w / w0 dr = 3n n K n - 3n K - 3n +1 exp - r r E E (52). where r = pore radius K = interaction constant = 2.96 kJ x nm3 x mol-1 (N2), = 2.34 kJ x nm3 x mol-1 (Ar) A plot of [d(w/w0)]/dr vs. r yields the DA Method pore size distribution. 10.3.6 Horvath-Kawazoe (HK) Method The HK method [23] enables the calculation of pore size distribution of micropores from the low relative pressure region of the adsorption isotherm. Many pore size distribution methods are derived from the Kelvin equation, which describes the phenomenon of capillary condensation. Some have questioned the reliability of the capillary condensation approach in the small confines of micropores. The HK method is derived independent of the Kelvin equation. The HK method expresses the adsorption potential function within slit-like micropores as a function of the effective pore width: Page 144 of 161 NOVAtouch™ Operating Manual RT ln THEORY AND DISCUSSION (53). 4 10 4 10 P N S AS + N A AA x + = K 9 3 9 d 3 4 -d P0 d d d 9 - 3 9 3 - 2 2 2 2 The parameters AS, and AA can be calculated using the following equations: AS = AA = 6 mc2 s A (54). 3 mc2 A A 2 (55). s + A s A where, m = mass of an electron c = speed of light s = polarizability of adsorbent A = polarizability of adsorptive s = magnetic susceptibility of adsorbent A = magnetic susceptibility of adsorptive and ( - ds) = effective pore width d = ds + dA ds = diameter of adsorbent molecule dA = diameter of adsorbate molecule l = distance between two layers of adsorbent σ = 0.858d/2 K = Avogadro’s number NS = number of atoms per unit area of adsorbent NA = number of molecules per unit area of monolayer of adsorbate AA = Kirkwood-Mueller constant of adsorptive AS = Kirkwood-Mueller constant of adsorbent By selecting effective pore widths in the micropore range, equation (51) can be used to calculate the corresponding relative pressures. From the adsorption isotherm, the amount of adsorption at each of these relative pressures is determined. Differentiation of weight (or Page 145 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION volume) of gas adsorbed relative to the total uptake, W/W0, with respect to the effective pore width yields a pore size distribution in the micropore range. 10.3.7 Saito-Foley (SF) Method Even though the HK method is adequate for materials with a predominance of slit-like pores (activated carbons, layered clays), certain solids (e.g. zeolites) are better represented assuming cylindrical pore geometry. Hence, the SF method [24] was developed as an alternative to the slit-like pore-based HK method. As with the HK method, the SF method enables the calculation of pore size distributions of microporous materials independently from the Kelvin Equation. The computational approach is analogous to that of the HK method, except that cylindrical pore geometry is assumed. Accordingly, equation (51) is replaced by RT ln P P0 = 3K x 4 d G = 1- D 2k N S AS + N A AA d /2 4 x 1 (56). k + 1 G k=0 10 4 21 d d ak - bk D D 32 (57). where 1.5 k ak k (58). 2 and a0 = b0 = 1 (D-ds) = effective pore diameter All of the other parameters have been defined in the previous section (HK method). The numerical solution of the above equations is again analogous to that of the HK method, and yields pore size distributions and cumulative pore volumes for cylindrical pores in the micropore range. Density Functional Theory and Monte Carlo Simulation Methods Classical macroscopic, theories like for instance the Dubinin-Radushkevich approach, the BJH method, and semi empirical treatments such as those of Horvath and Kawazoe (HK), and Saito and Foley do not give a realistic description of the filling of micropores and even narrow mesopores. This leads to an underestimation of pore sizes. In order to achieve a more realistic description microscopic theories, which describe the sorption Page 146 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION and phase behavior of fluids in narrow pores on a molecular level, are necessary. Treatments such as the Density Functional Theory (DFT) or methods of molecular simulation (Monte Carlo simulation (MC) and Molecular Dynamics (MD)) provide a much more accurate approach for pore size analysis. Hence, methods such as the DFT of inhomogeneous fluids [25, 26] and Monte Carlo simulations [27, 28] bridge the gap between the molecular level and macroscopic approaches. The Non-Local Density Functional Theory (NLDFT) and the Grand Canonical Monte Carlo simulation (GCMC) methods correctly describe the local fluid structure near curved solid walls; adsorption isotherms in model pores are determined based on the intermolecular potentials of the fluid-fluid and solid-fluid interactions. The relation between isotherms determined by these microscopic approaches and the experimental isotherm on a porous solid can be interpreted in terms of a Generalized Adsorption Isotherm (GAI) equation: 𝑊𝑚𝑎𝑥 𝑁(𝑃⁄𝑃𝑜 ) = (59). ∫ 𝑁(𝑃⁄𝑃𝑜 , 𝑊 ) 𝑓(𝑊)𝑑𝑊 𝑊𝑚𝑖𝑛 where N(P/Po) = experimental adsorption isotherm data, N(P/Po,W) = isotherm on a single pore of width W, f(W) = pore size distribution function The GAI equation reflects the assumption that the total isotherm consists of a number of individual “single pore” isotherms multiplied by their relative distribution, f(W), over a range of pore sizes. The set of N(P/Po,W) isotherms (kernel) for a given system (adsorbate/adsorbent) can be obtained, as indicated above, by either Density Functional Theory or by Monte Carlo computer simulation. The pore size distribution is then derived by solving the GAI equation numerically via a fast non-negative least square algorithm. The DFT and the Monte Carlo simulation method have largely been applied to the characterization of micro- and mesoporous carbons [28-30], silicas, and zeolites [28,31,32]. (Please contact qc.support@Quantachrome.com for Powder Tech Notes 27, 31 and 36 for more details). The NLDFT/CO2/273K/carbon kernel is based on a common, one-center, Lennard-Jones model. This kernel is important in case a comparison with appropriate DFT-results in the literature is needed. However, in the case of the GCMC/CO2/273K/carbon kernel, a three-center potential function has been developed with interactions between the sites of different molecules modeled as a sum of Lennard-Jones and electrostatic contributions. Hence, the GCMC model may serve as a benchmark for quantitative estimates [30]. For details about the application of CO2 NLDFT/GCMC kernels please contact qc.support@Quantachrome.com for Quantachrome’s Powder Tech Note 35. In contrast to regular NLDFT, the QSDFT method (Quenched Solid Density Functional Theory) [46], explicitly takes into account the effects of surface roughness and heterogeneity (i.e. geometrical and chemical disorder) of a carbon surface. This allows one to perform pore size analysis of carbons with different degrees of surface heterogeneity, and to assess the reliability of the pore size analysis of unknown carbon samples. Methods based on NLDFT are however more Page 147 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION accurate for ordered (homogenous) carbons. For more details see Quantachrome’s Powder Tech Note 40 (contact qc.support@Quantachrome.com). TouchWin™ software includes a number of kernels consisting of individual (P/P0,W) isotherms derived for the systems: nitrogen-carbon, argon-carbon, nitrogen-silica, and argon-silica by Non-Local Density Functional Theory and Grand Canonical Monte Carlo computer simulation. Please refer to 10.4.1 for a detailed listing and recommendations for the pore width ranges where these models are appropriate. 10.4.1 Library of DFT and GCMC Methods in Quantachrome’s Data Reduction Software Kernel File Applicable Pore Width Range (nm) Examples NLDFT N2 / 77K Carbon, equilibrium transition (desorption) kernel, slit pore model 0.35-40 Activated carbons, activated carbon fibers, novel micro/mesoporous carbons of type CMK-1 etc. NLDFT N2 / 77K Carbon, equilibrium transition (desorption) kernel, cylindrical pore model 0.35-40 Novel micro/mesoporous carbons (e.g. CMK-3, carbon nanotubes, carbon aerogels) etc. NLDFT N2 / 77K Carbon, equilibrium transition (desorption) kernel, slit pore model for widths < 2nm, cylindrical pore model for widths > 2nm 0.35-40 Novel micro/mesoporous carbons (some CMK’s), certain activated carbons. NLDFT N2 / 77K Silica, adsorption branch kernel, cylindrical pore model 0.35-100 Siliceous materials such as controlled pore glasses, MCM-41, SBA-15, MCM-48, and others. Accurate pore size distribution even in case of type H2 hysteresis. NLDFT N2 / 77K Silica, adsorption branch kernel, cylindrical pore model for diameters < 5 nm, spherical pores model for diameters > 5 nm 0.35-40 Novel siliceous materials with hierarchically ordered pore structure, SBA-16 silica, some types of porous glasses and some types of silica gels. NLDFT N2 / 77K Silica, equilibrium transition (desorption) kernel, cylindrical pore model 0.35-100 Siliceous materials, e.g. some types of silica gels, porous glasses, MCM-41, SBA-15, MCM-48 and other adsorbents which show type H1 sorption hysteresis NLDFT Ar / 87K Zeolite/silica, equilibrium transition (desorption) kernel, cylindrical pore model 0.35-100 Zeolites with cylindrical pore channels such as ZSM5, mordenite, and mesoporous siliceous materials e.g., MCM-41, SBA-15, MCM-48, some porous glasses (e.g. CPG) and silica gels which show type H1 sorption hysteresis. NLDFT Ar / 87K Zeolite/silica, adsorption branch kernel, cylindrical pore model 0.35-100 Zeolites with cylindrical pore channels such as ZSM5, Mordenite etc., and mesoporous siliceous materials such as MCM-41, SBA15, MCM-48, porous glasses and some silica gels etc. Accurate pore size distribution even in case of type H2 hysteresis. Page 148 of 161 NOVAtouch™ Operating Manual Kernel File THEORY AND DISCUSSION Applicable Pore Width Range (nm) Examples NLDFT Ar / 87K Zeolite/silica equilibrium transition (desorption) kernel, spherical pore model for diameters < 2 nm cylindrical pore model for diameters > 2 nm 0.35-100 Zeolites with cage-like structures such as Faujasite, 13X etc. NLDFT Ar / 87K Zeolite/silica adsorption branch kernel, spherical pore model for diameters < 2 nm cylindrical pore model for diameters > 2 nm 0.35-40 Zeolites with cage-like structures such as Faujasite, 13X etc. NLDFT Ar / 87K Carbon equilibrium transition (desorption) kernel, cylindrical pore model 0.35-7 Novel micro/mesoporous carbons (e.g. CMK-3), carbon nanotubes, carbon aerogels, and others. NLDFT Ar / 87K Carbon equilibrium transition (desorption) kernel slit-pore model 0.35-40 Activated carbons, activated carbon fibers, novel micro/mesoporous carbons of type CMK-1, and others. NLDFT Ar / 87K Carbon equilibrium transition (desorption) kernel, slit-pore model 0.35-1.5 Activated carbons, activated carbon fibers, novel micro/mesoporous carbons of type CMK-1, and others. NLDFT CO2 / 273K Carbon equilibrium transition (desorption) kernel, slit-pore model 0.35-1.5 Ultramicroporous activated carbons, activated carbon fibers. GCMC CO2 / 273K Carbon equilibrium transition (desorption) kernel, slit-pore model 0.35-40 Ultramicroporous activated carbons, activated carbon fibers. QSDFT N2 / 77K Carbon equilibrium transition (desorption) kernel, slit-pore model 0.35-40 Disordered Micro/Mesoporous carbons with heterogeneous surface chemistry (e.g. activated carbons, activated carbon fibers) Fractal Dimension Methods NOTE! Fractal Dimension is intended for investigation using data acquired in the micropore region (below a relative pressure of 1x10-3). Thus, data from the NOVAtouch is not appropriate for this calculation. Nevertheless, TouchWin can be used to evaluate data from low pressure instruments such as the Autosorb-iQ. Surface characterization methods based on fractal geometry [36-39] describe the topography of real surfaces in terms of a "roughness exponent" known as fractal dimension, D. Ideal surfaces, being relatively smooth, can be modeled using simple geometric concepts (e.g., 6L2 for cubes, 4πR2 for spheres, etc.). For such surfaces D=2, because the surface area is proportional to X2, where X is some characteristic dimension of the adsorbent (e.g., X=L for squares, R for circles, etc.). In contrast, real surfaces are generally rough because of atom packing arrangements and defects, kinks and dislocations, and pores themselves, depending on the scale considered. Many real surfaces present surface irregularities that appear to be similar at different scales. These surfaces are referred to as fractal because their magnitude is proportional to X D, Page 149 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION where D is a fractional exponent that generally assumes values between D=2 (for smooth surfaces) and D=3 (for surfaces so rough that they essentially occupy all available volume). The fractal dimension D can thus be used to quantify the roughness of real surfaces in terms of a single parameter. Among the various approaches proposed in the literature to evaluate D, two in particular have gained popularity because they make use of single gas sorption isotherms for their calculations. These are the Frenkel-Halsey-Hill (FHH) method and the Neimark-Kiselev (NK) method [37-39]. 10.5.1 Frenkel-Halsey-Hill (FHH) Method By noting that in the multilayer adsorption region the influence of surface forces tends to be smoothed out, several independent authors derived an isotherm expression of the general form [38]. B log P0 = s P V (60). where B is a parameter related to adsorbate-adsorbent and adsorbate-adsorbate interactions, V is the amount of adsorbed material, and the exponent s is a constant characteristic of a given adsorbent. Equation (60) came to be known as the Frenkel-Halsey-Hill (or FHH) equation. Pfeifer et al. [37-39] postulated that the FHH exponent s is related to the fractal dimension D of the adsorbent through the expression 𝐷 = 3(1 + 𝑠) (61). In deriving equation (61) surface tension effects were neglected. That is, the assumption was made that the surface tension of the adsorbate at a molecular scale does not differ appreciably from its bulk liquid value. If surface tension effects are accounted for [39], the relationship between D and s is given by: 𝐷 =3+𝑠 (62). where, D is the surface fractal dimension, and s is a constant characteristic of a given adsorbent. In either case, for fractal surfaces a plot of log V vs. log [log(P0/P)] should yield a straight line with negative slope s within the multilayer region of the isotherm. 10.5.2 Neimark-Kiselev (NK) Method Combining thermodynamic and fractal arguments, Neimark [38] reasoned that above the onset of capillary condensation fractal surfaces should conform to the following equation: S lg = K ac 2- D (63). Page 150 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION where, D is the surface fractal dimension, K is a constant, ac is the mean radius of curvature of the adsorbate-vapor interface, given by the Kelvin equation: ac = r k = 2 Vm R T ln PP0 (64). and Slg is the adsorbate-vapor interface area, given by the Kiselev equation: Slg RT n max n p ln o dn p (65). with R being the universal gas constant, T the adsorption temperature, γ the adsorbate surface tension, Vm the adsorbate molar volume, and n and nmax the amounts of gas adsorbed at a given P/Po and at saturation, respectively. In other words, the cumulative area Slg was taken to be equivalent to the adsorbent area measurable with a yardstick of a size proportional to ac at any given P/Po. Accordingly, a plot of log [Slg] vs. log [ac] should also yield a straight line within the multilayer region of the isotherm, from which the fractal dimension D can be readily calculated. Thermal Transpiration At the low pressures commonly employed for nitrogen and argon micropore characterization, the phenomenon of thermal transpiration [33-35] can result in significant pressure measurement errors if not compensated. Thermal transpiration results in a pressure gradient between the sample at temperature, T1 and pressure, P1 and the pressure transducer at temperature T2 and pressure P2 if the inner diameter of the tubing between the two parts of the system is very small compared with the mean free path of the gas. The relationship between pressure and temperature can be expressed as follows for very low pressures: 𝑇1 𝑃1 = 𝑃2 √ 𝑇2 (66). At higher pressures, the empirical model of Liang [34, 35] can be employed to calculate thermal transpiration corrections for measured pressures. 𝑇 𝛼𝜑 2 𝑥 2 + 𝛽𝜑𝑥 + √𝑇1 (67). 𝑃1 2 = 𝑃2 𝛼𝜑 2 𝑥 2 + 𝛽𝜑𝑥 + 1 where P1, P2 are in Pascal Page 151 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION x = 0.133P2d d = diameter of connecting tube (in meters) α = 2.52 (for helium) β = 7.68(1 − √𝑇1 ⁄𝑇2 ) (for helium) φ = the pressure shift factor that varies for gases relative to the value 1.00 for helium and can be calculated by 0.27𝑙𝑜𝑔𝜑 = 𝑙𝑜𝑔𝐷 + 9.59 (68). where D is the molecular diameter of the gas (in meters). Heats of Adsorption Whenever a gas molecule adsorbs on a surface, heat is (generally) released. This heat comes mostly from the loss of molecular motion associated with a change from a 3-dimensional gas phase to a 2-dimensional adsorbed phase. Heats of adsorption provide information about the chemical affinity and the heterogeneity of a surface, with larger amounts denoting stronger adsorbate-adsorbent bonds. There are at least two ways to quantify the amount of heat released upon gas adsorption: in terms of differential heats of adsorption (q) and as an integral heat of adsorption (Q). Both methods are described in turn below. 10.7.1 Differential Heats of Adsorption (q) The differential heat of adsorption (q) is defined as the heat released upon adding a small increment of adsorbate to the surface of a solid. The value of q depends on (i) the strength of the bonds formed upon adsorption, and (ii) the degree to which a surface is already covered with adsorbate. Hence, q is most often expressed in terms of its variation with adsorbate surface coverage (θ). Indeed, a plot of q against θ provides a characteristic curve illustrating the energetic heterogeneity of a solid surface. This curve not only serves as a fingerprint of the surface energetics of a given sample, but it also allows a direct test of the validity of any Vm evaluation method used, since each Vm evaluation method assumes a different relationship between q and θ that is, Langmuir method: q remains constant with increasing θ, Temkin method: q decreases linearly with increasing θ, and Freundlich method: q decreases exponentially with increasing θ. Since q can vary with θ, it is convenient to express q as an isosteric heat of adsorption. (The word isosteric implies equal surface coverage θ.) In order to evaluate this q, one must collect two or more isotherms at different temperatures. By inspecting plots of coverage (where θ = V/Vm) vs. pressure, one can determine those pressures corresponding to equal coverage at the different temperatures. These pressures and temperatures can then be used to construct Arrhenius Plots of the natural log of pressure (lnP) versus the reciprocal of the absolute temperature (1/T). Values Page 152 of 161 NOVAtouch™ Operating Manual THEORY AND DISCUSSION for q at any given coverage (θ) can be calculated from the slope (m) of each Arrhenius plot using the following equation: q= - m R (69) where m = d lnP/d(1/T) and R is the universal gas constant. Differential heats of adsorption are commonly expressed in units of kilocalories (or kcal) per mol of adsorbate taken up by the sample. 10.7.2 Integral Heat of Adsorption (Q) This is simply defined as the total amount of heat released when 1 gram of adsorbent takes up X grams of adsorbate. It is equivalent to the integral of q over the adsorption range considered, i.e. V m max Q= q d 22.4 min (70) where Q is expressed in calories per gram of adsorbent (or cal/g), Vm is cc(STP)/g, and q is a function of θ, with θ ranging (ideally) from θmin = 0 to θmax = maximum coverage attained experimentally. Page 153 of 161 NOVAtouch™ Operating Manual APPENDIX 11 APPENDIX Troubleshooting Guide Symptom Open isotherm (desorption branch always lies above adsorption branch even at low relative pressure Reason Action Under-equilibrated conditions If isotherm is unexpectedly open, extend the desorption equilibration time. Microporous materials often need longer desorption equilibration times Incomplete degassing Extend degassing time and/or increase degassing temperature Leaks Check integrity of O-ring on sample cell. Make sure O-ring is lightly greased. Make sure that the bulkhead does not have multiple O-rings Incorrect cell geometry defined during calibration Choose proper cell calibration file. Sample measurement conditions must be identical (temperature, use of filler rod) to the cell calibration conditions System contamination Pump down unit overnight Dewar goes up but analysis hangs Upper limit switch not hit Check for obstruction to Dewar travel Unit fails vacuum integrity test Vacuum hose and/or fittings are leaking Check hose and tighten fittings. Replace as necessary Sample elutriates during degassing See “8.3.4, Elutriation and Its Prevention” Instrument does not power up Wall outlet has no power Check wall outlet Power cord is not plugged in to the wall outlet Plug cord in to wall outlet Blown fuse Replace fuse Internal surge protector blown Contact Quantachrome Service Department Power switch does not illuminate even though unit powers up Internal light burned out Replace switch Touchscreen is blank Video input cable to Touchscreen is disconnected Check or reseat both ends of the video cable Crossed isotherm (desorption branch lies below adsorption branch at some relative pressure) Page 154 of 161 NOVAtouch™ Operating Manual Power input cable to Touchscreen is disconnected. Degassing compartment is dark Check or reseat both ends of the power LED light cable disconnected. LED light burned out Analysis compartment is dark APPENDIX LED light cable disconnected. Non critical malfunction. Possible loose connections. Contact Service Department, if desired LED light burned out Heating mantle(s) not heating when the temperature profile is started Heating mantles may not be connected. Check the LED diagnostic panel HEATING: If not flashing, mantle might be disconnected Check the LED diagnostic panel (on the side of the instrument) for the following: A) HEAT CMD: If the heat command is not flashing check the profile setting. B) HEATING: If heating is not flashing. Mantle is burned or disconnected. C) OVERTEMP: If overtemp is on, check the thermocouple cable Mantle temperature already above program start temperature Wait for heating profile to exceed current mantle temperature The mantle may be burnt out. Check the LED diagnostic panel HEATING: If not flashing. Mantle is burned or disconnected Replace mantle Check the LED diagnostic panel HEAT CMD: If not flashing, check the profile setting Edit profile in TouchWin™ and upload to NOVAtouch™ Dewar is at the top and the instrument seems to be locked up The instrument may be in cleanup Check the log for information Powering the unit up trips the lab circuit breaker Electrical problem Contact Quantachrome Service Incomplete analysis Insufficient LN2 Check the log for information Analysis self-aborts Check the log for information Page 155 of 161 NOVAtouch™ Operating Manual APPENDIX Maintenance In order to keep the instrument running at a high standard consistently, it is advised that a maintenance plan is established using the following guidelines recommended by Quantachrome Instruments. The service kit listed will provide the necessary parts for a maintenance routine such as new filters and O-rings. If desired, the Quantachrome Instruments Service Department can install the service kit. For any questions or concerns regarding the maintenance plan, please contact the Quantachrome Instruments Service Department. The following chart details the suggested schedule for instrument maintenance. It includes the items that may be necessary when organizing a maintenance procedure for your instrument. Table 11-1, Preventative Maintenance Plan Maintenance Item Recommended Frequency Performed by Name of Part Needed Part Number Check and Inspect Heating Mantles Every Six Months User Change Oil in Oil Pump Install Service Kit Every Six Months User Pump Oil 91029 Every Year Service Technician NOVAtouch™ Service Kit 33022-NOVA TOUCH Replace All Valve Disks Every Year Service Technician Valve Spider Disc 50042-4 Inspect & Grease the Lift Drive Every Year Service Technician Vacuum Grease 91000-.25 Replace All Filters Every Year Every Five Years 60 micron Filtered Screw Valves 01568 Replace All Valves Service Technician Service Technician 50050 Page 156 of 161 NOVAtouch™ Operating Manual APPENDIX Spare Parts List Description Low Temp Heating Mantle High Temp Heating Mantle Input Line, 5’ SS Male Input Line, 5’ SS Nova e NOVA touch Backfill Line Cable Shielded CAT 5e Ethernet Sample Cell Cooling Rack 1/8” Nut (Female) & Ferrule Set, Brass 1/8” Nut (Male) 1/8” Ferrule Set, Brass Long Flow Degasser Adapter Assembly Glass Filler Rod Long 6 mm X 268.5 mm Glass Filler Rod Short 6 mm X 131.5 mm Glass Filler Rod Long 3 mm X 268.5 mm Glass Filler Rod Short 3 mm X 131.5 mm Glass Filler Rod Long 9 mm X 268.5 mm Part Number 24020-L-JJ-CE-NT 24021-L-JJ-CE-NT 01003-V 01003-1SL 01999-10851 26102-25 01999-10856 01071 41230 40032 01308-3941L 74105-L 74105-S 74104-L 74104-S 74106-L Glass Filler Rod Short 9 mm X 131.5 mm 9 mm Cell Adapter 6 mm Cell Adapter 12 mm Cell Adapter Sample Cell Funnel, Delrin 2L Dewar 1L Dewar (Short Cell) Coolant Level Sensor Short Coolant Level Sensor Po Cell Short Po Cell NOVA touch Po Collar H2O Level Sensor *Fuses for 100-120V *Contact Quantachrome’s Service Dept. *Fuses for 220-240V *Contact Quantachrome’s Service Dept. Line Cord, Domestic (USA) 74106-S 04000-3499-2 04000-3499-1 04000-3499-3 04000-3595 74215 Line Cord, International ™ TouchWin Software Flange, Brass, Stub Centering Ring, KF16 74218 00080-CLS 00080-CLS-S 74027 74027-S 04000-10844 00080-H2O-NT 1 A (P/N 24163), .25 A (P/N 24165), 5 A (P/N 24074) 1 A slow (P/N 24152), 1 A (P/N 24163) .25 A (P/N 24165), 2.5 A (P/N 24073) 26007 26069 36381-1.1NTCD 44019 44028 Page 157 of 161 NOVAtouch™ Operating Manual APPENDIX Clamp, Alum. KF16 44030 Vardex ¾” I.D. Vacuum Tubing 46025 O-Ring Buna, 010 Clamp, Hose, 1” I.D. Nova, 9mm, large bulb, long cell 51000-010 71018 74064 Nova, 9 mm Large Bulb short cell 74064-1 Nova, 9 mm Small Bulb long cell 74063 Nova, 9 mm Small Bulb short cell 74063-1 Nova, 6 mm Large Bulb long cell 74062 Nova, 6 mm Large Bulb short cell 74062-1 Nova, 6 mm Small Bulb long cell 74061 Nova, 6 mm Small Bulb short cell 74061-1 Nova, 12 mm Large Bulb short cell 74066-1 Nova, 12 mm Small Bulb long cell 74065 Nova, 12 mm Small Bulb short cell 74065-1 Nova, Std. 9 mm Pel. Long 74099 Nova, Std. 9 mm Pel. Short 74099-S Nova, Std. 6 mm Pellet Cell Long 74098 Nova, Std. 6 mm Pellet Cell Short 74098-S Nova, Std. 12 mm Pellet Cell Long 74100 Nova, Std. 12 mm Pellet Cell Short 74100-S 6mm X 12” Stems Cleaner (1 Doz.) 96036 Description Low Temp Heating Mantle High Temp Heating Mantle Input Line, 5’ SS Male Input Line, 5’ SS Nova e NOVA touch Backfill Line Cable Shielded CAT 5e Ethernet Sample Cell Cooling Rack 1/8” Nut (Female) & Ferrule Set, Brass 1/8” Nut (Male) 1/8” Ferrule Set, Brass Long Flow Degasser Adapter Assembly Glass Filler Rod Long 6 mm X 268.5 mm Part Number 24020-L-JJ-CE-NT 24021-L-JJ-CE-NT 01003-V 01003-1SL 01999-10851 26102-25 01999-10856 01071 41230 40032 01308-3941L 74105-L Page 158 of 161 NOVAtouch™ Operating Manual APPENDIX Glass Filler Rod Long 3 mm X 268.5 mm Glass Filler Rod Long 9 mm X 268.5 mm 74104-L 74106-L 9 mm Cell Adapter 6 mm Cell Adapter 12 mm Cell Adapter Sample Cell Funnel, Delrin 2L Dewar Coolant Level Sensor Po Cell NOVA touch Po Collar H2O Level Sensor *Fuses for 100-120V *Contact Quantachrome’s Service Dept. *Fuses for 220-240V *Contact Quantachrome’s Service Dept. Line Cord, Domestic (USA) 04000-3499-2 04000-3499-1 04000-3499-3 04000-3595 74215 00080-CLS 74027 04000-10844 00080-H2O-NT 1 A (P/N 24163), .25 A (P/N 24165), 5 A (P/N 24074) Line Cord, International ™ TouchWin Software Flange, Brass, Stub 1 A slow (P/N 24152), 1 A (P/N 24163) .25 A (P/N 24165), 2.5 A (P/N 24073) 26007 26069 36381-“X.YY”NTCD 44019 Centering Ring, KF16 44028 Clamp, Alum. KF16 44030 Vardex ¾” I.D. Vacuum Tubing 46025 O-Ring Buna, 010 Clamp, Hose, 1” I.D. Nova, 9mm, large bulb, long cell 51000-010 71018 74064 Nova, 9 mm Small Bulb long cell 74063 Nova, 6 mm Large Bulb long cell 74062 Nova, 6 mm Small Bulb long cell 74061 Nova, 12 mm Small Bulb long cell 74065 Nova, Std. 9 mm Pel. Long 74099 Nova, Std. 6 mm Pellet Cell Long 74098 Nova, Std. 12 mm Pellet Cell Long 74100 6mm X 12” Stems Cleaner (1 Doz.) 96036 Page 159 of 161 NOVAtouch™ User Manual REFERENCES 12 REFERENCES 1. S. Brunauer, P. Emmett and E. Teller, J. Amer. Chem. Soc., 60, 309 (1938). 2. V. Kiselev and Y. A. Eltekov, World Congress on Surface Activity, Vol. II, p. 228, Butterworths, London, 1957. 3. S. Lowell, J. Shields, G. Charalambous and J. Manzione, J. Colloid Interface Sci., 86, 191 (1982). 4. S. Brunauer, L. S. Deming, W. S. Deming and E. Teller, J. Amer. Chem. Soc., 62, 1723 (1940). 5. J. H. de Boer, “The Structure and Properties of Porous Materials,” p. 68, Butterworths, London, (1958). 6. J. H. de Boer, B. C. Lippens, B. G. Lippens, J. C. P. Broekhoff, A. van den Heuvel and Th. V. Osinga, J. Colloid Interface Sci., 21, 405 (1966). 7. E. P. Barrett, L. G. Joyner and P.P. Halenda, J. Amer. Chem. Soc., 73, 373 (1951). 8. D. Dollimore and G.R. Heal, J. Appl. Chem. 14, 109 (1964). 9. G.D. Halsey, J. Chem. Phys., 16, 931 (1948). 10. J. H. de Boer, B. G. Linsen, Th. van der Plas and G. J. Zondervan, J. Catalysis, 4, 649 (1965). 11. R. W. 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