Siddhartha Das Postdoctoral Researcher Physics of Fluids Group, Department of Applied Physics University of Twente, Enschede, the Netherlands AREA OF INTEREST: Investigations of fluid flow and analysis of separation, reaction and dynamics of biological macromolecules in micro and nanochannels. Study of nanobubble formation in different geometries in the open and in confinements, under different electrohydrodynamic conditions. CORRESPONDENCE DETAILS: Permanent address: Flat 3E, Sankosima Apartment 56, Mahesh Paul Lane, Santragachi Howrah – 711 104 Present Address: Room 249, Building MEANDER Chair, Physics of Fluids Faculty of Scinece and Technology, University of Twente Drienerlolaan 5, 7522 NB, Enschede, The Netherlands Telephone Number : +91-9239538214 (India), +31 (0) 53 489 2487 (The Netherlands) E-mail: siddhartha_iit@yahoo.com / siddhartha.iit@gmail.com PERSONAL DETAILS: Date of Birth: 7th May, 1982 Nationality: Indian Parents: Pradip Ranjan Das and Manju Das Spouse: Urmita Sengupta Mother Tongue: Bengali Other Languages Known: English, Hindi 1 EDUCATION: Degree Board/Council/Univ. Postdoctoral Researcher (Supervisor: Prof. Detlef Lohse) PhD (Supervisor: Prof. Suman Chakraborty) B.Tech. (Hons) (Mechanical) Physics of Fluids Group, Dept. of Applied Physics University of Twente, Enschede, the Netherlands Indian Institute of Technology, Kharagpur, India Indian Institute of Technology, Kharagpur, India West Bengal Council of Higher Secondary Education, India West Bengal Board of Secondary Education, India 12th Standard 10th Standard Percentage /CGPA Year Of Passing October, 2009 to October, 2011 Thesis Submitted on May, 2009 8.9/10 2005 89.4 % 2001 89 % 1999 HONOURS AND ACHIEVEMENTS: ? Selected for Non-EU Postdoctoral Fellowship (for Indian Students) by Belgium Federal Science Office for 2009-2010 (Offer Declined). ? Recipient of prestigious High Value Fellowship for PhD, offered by Indian Institute of Technology, Kharagpur for the period 2007-2009. ? Recipient of National Doctoral Fellowship, offered by All India Council of Technical Education. ? Only STUDENT participant to give Oral Presentation in Singapore International Chemistry Conference 5 & APCE Asia Pacific International Symposium on Microscale Separation and Analysis, 2007 (16-19, December, 2007 Singapore). ? Selected by Indo-US Joint Centre for Advanced and Futuristic Manufacturing to serve as a Junior Specialist for a period of one month (August 2006) at University of California, Irvine. ? Selected by Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur to do direct PhD (without Masters) after B-Tech on the basis of excellent Academic and Project performances in the Undergraduate Level. 2 ? Recipient of the Innovative Student Projects Award-2005 (B-Tech level) offered by Indian National Academy of Engineering for the thesis titled “Modeling of Coupled Momentum, Heat and Solute Transport during DNA Hybridization in a Microchannel in Presence of Electroosmotic Effects and axial Pressure Gradients.” ? Recipient of the S.P. Sengupta Memorial Award-2005, offered by Indian Institute of Technology, Kharagpur for the best project on Computational Fluid Dynamics for the thesis titled “Modeling of Coupled Momentum, Heat and Solute Transport during DNA Hybridization in a Microchannel in Presence of Electroosmotic Effects and axial Pressure Gradients.” ? Ranked 4th in a batch of around 100 students at the B-Tech level. ? Secured a rank of 15 in West Bengal Joint Entrance Examination (WBJEE) (Engineering) among around 40,000 candidates. ? Secured a rank of 740 in Indian Institute of Technology Joint Entrance Examination (IITJEE) among around 1,50,000 candidates. PUBLICATIONS: Book Chapter Chapter titled “Polymer Transport in Nanochannels” by Suman Chakraborty and Siddhartha Das to appear in the Book entitled “Microfluidics and Nanofluidics Handbook: Fabrication, Implementation and Applications-Vol II” published by Taylor and Francis Group International Journal Papers (in Reverse Chronological Order): 1. Siddhartha Das and Suman Chakraborty, “Influence of Streaming Potential on the Transport and Separation of Charged Spherical Solutes in Nanochannels Subjected to Particle-Wall Interactions” Langmuir, Vol-25, 9863-9872 (2009). 2. Suman Chakraborty and Siddhartha Das, “Transport of Flexible Molecules in Narrow Confinements” (Invited Review: to appear in the First Issue of the journal International Journal of Micro and Nanoscale Transport Processes) 3. Siddhartha Das and Suman Chakraborty, “Augmented surface adsorption characteristics by employing patterned microfluidic substrates in conjunction with transverse electric fields”, Microfluidics and Nanofluidics (DOI 10.1007/s10404009-0462-1). 3 4. Tamal Das, Siddhartha Das and Suman Chakraborty, “Influences of Streaming Potential on Cross Stream Migration of Flexible Polymer Molecules in Nanochannel Flows” The Journal of Chemical Physics, Vol-130, 244904 (2009). (This paper has been selected for the July 1, 2009 issue of Virtual Journal of Biological Physics Research in the section “Fundamental Polymer Statics/Dynamics”. The Virtual Journal, which is published by the American Physical Society and the American Institute of Physics in cooperation with numerous other societies and publishers like is an edited compilation of links to articles from participating publishers, covering a focused area of frontier research) 5. Siddhartha Das and Suman Chakraborty, “Transport and Separation of Charged Macromolecules under Nonlinear Electromigration in Nanochannels” Langmuir, Vol-24(15), 7704-7710 (2008). 6. Suman Chakraborty and Siddhartha Das, “Streaming Field Induced Convective Transport and its Influence on the Electroviscous effects in Narrow Fluidic Confinements Beyond the Debye Huckel Limits” Physical Review E, Vol-77, 037303 (1-4) (2008). 7. Ruth Lambert, Siddhartha Das, Marc Madou, Suman Chakraborty and Roger Rangel, “Simulation of a Moving Mechanical Actuator for Fast Biomolecular Synthesis Process” International Journal of Heat and Mass Transfer, Vol-51, 4367-4378 (2008). 8. Siddhartha Das and Suman Chakraborty, “Separation of Charged Macromolecules in Nanochannels within the Continuum Regime: Effects of Wall Interactions and Hydrodynamic Confinements” Electrophoresis, Vol – 29, 1115-1124 (2008). (Published in Special Issue: Fundamentals of Electrophoresis). 9. Siddhartha Das, Kapil Subramanian and Suman Chakraborty, “Analytical Investigations on the Effects of Substrate Kinetics on Macromolecular Transport and Hybridization through Microfluidic Channels” Colloids & Surfaces B: Biointerfaces, Vol – 58, 203-217 (2007). 10. Siddhartha Das and Suman Chakraborty, “Transverse electrodes for improved DNA hybridization in microchannels” AIChE Journal, Vol – 5, 1086-1099 (2007). 11. Siddhartha Das and Suman Chakraborty, “Augmentation of macromolecular adsorption rate through Transverse Electric Fields generated across Patterned Walls of a Microfluidic Channel” Journal of Applied Physics, Vol – 99, pp- 1-8 (2006). (This paper has been selected for the July 15, 2006 issue of Virtual Journal of Biological Physics Research in the section “Instrumentation Development”). 12. Siddhartha Das and Suman Chakraborty, “Analytical Solutions for Velocity, Temperature and Concentration Distribution in Electroosmotic Microchannel Flows of a Non-Newtonian Bio-fluid” Analytica Chimica Acta, Vol – 559, pp- 15-24 (2006). 13. Siddhartha Das, Tamal Das and Suman Chakraborty, “Analytical Solutions for the rate of DNA hybridization in a microchannel in the presence of pressure-driven and electroosmotic flows” Sensors and Actuators B, Vol -114, pp- 957-963 (2006). 4 14. Siddhartha Das, Tamal Das and Suman Chakraborty, “Modeling of coupled momentum, heat and solute Transport during DNA hybridization in a microchannel in presence of electro-osmotic effects and axial pressure gradients” Microfluidics and Nanofluidics, Vol - 2, pp- 37-49 (2006). International Conference Proceedings (in Reverse Chronological Order): 1. Siddhartha Das and Suman Chakraborty, “Influence of Electric Double Layer conductivity on the electroviscous effects in narrow fluidic confinements”, 20th National & 9th ISHMT-ASME Heat and Mass Transfer Conference, January 4-6, 2010, IIT Bombay, India. 2. Siddhartha Das and Suman Chakraborty, “Electroviscous Effects in Narrow Fluidic Confinements beyond the Debye-Hückel Limits” IISc Centenary-International Conference on Advances in Mechanical Engineering (IC-ICAME), July 2-4, 2008, Bangalore, India. 3. Sisir Das, Siddhartha Das and Suman Chakraborty, “Molecular Dynamics Simulation of Water Flow through Nanochannels”, 19th National & 8 th ISHMTASME Heat and Mass Transfer Conference, January 3 - 5, 2008, JNTU Hyderabad, India. 4. Siddhartha Das, Sourav Singh and Suman Chakraborty, “Time-Periodic Electroosmotic Transport of a non-Newtonian Bio-fluid”, 19th National & 8th ISHMT-ASME Heat and Mass Transfer Conference, January 3 - 5, 2008, JNTU Hyderabad, India. 5. Siddhartha Das and Suman Chakraborty, “Role of Substrate Kinetics on Macromolecular Transport and Hybridization in Microchannels”, 19th National & 8th ISHMT-ASME Heat and Mass Transfer Conference, January 3 - 5, 2008, JNTU Hyderabad, India. 6. Siddhartha Das, Saugata DuttaRoy and Suman Chakraborty, “Nonlinear Effects in Electrokinetic Separation of Charged Macromolecules in Nanochannels”, Proceedings of SICC5/APCE 2007, December 16-19, 2007, Suntec City, Singapore. 7. Siddhartha Das, Tamal Das and Suman Chakraborty, “An Integrated Thermo-Fluid Analysis of Electroosmotic Separation of Biological Macromolecules in Microchannels”, 18th National & 7 th ISHMT-ASME Heat and Mass Transfer Conference, January 4 - 6, 2006, IIT Guwahati, India. Invited Talks 1. Talk on “Electroviscous Effects in Narrow Fluidic Confinements” in IISc Centenary International Conference on Advances in Mechanical Engineering (IC-ICAME), held at Bangalore, India (July, 2008). 5 2. Talk on “Nonlinear Effects in Electrokinetic Separation of Charged Macromolecule in Nanochannels” in Singapore International Chemistry Conference-5 (SICC5) held at Suntec City, Singapore. (December, 2007). 3. Talk on “Combined pressure-driven and electroosmotic microchannel transport for enhanced DNA Hybridization” in Department of Mechanical Engineering, University of California, Irvine, USA (August, 2006). Abstract of the PhD Thesis Title: Electrokinetic Transport and Separation in Nanofluidic Channels Nanofluidics primarily encompasses the fundamental principles and applications concerning fluid flow and transport processes in conduits having at least one characteristic dimension less than 100 nm. Over such length scales, extremely large surface area-to-volume ratios of the devices may give rise to intriguing transport phenomena, remarkably distinctive as compared to what is observed in macrofluidic or microfluidic systems. The present study focuses on three important and inter-related facets of transport phenomena in nanofluidic channels. First, a comprehensive mathematical model is developed to describe electroviscous effects in nanochannels, which may originate from the fact that the counterions in the mobile part of the electrical double layer (EDL) are preferentially transported towards the down-stream end of the flow conduit with a pressure-driven liquid motion. This causes an electrical current, known as the streaming current, to flow in the direction of the imposed fluid motion. However, the resultant accumulation of ions in the downstream section of the channel sets up its own induced electrical field, known as the streaming potential. This field, in turn, generates a current to flow back against the direction of the pressure-driven flow, so as to enhance the effective viscosity of flow (an artifact also known as electroviscous effect). A novel mathematical model is first developed in this work to predict the streaming potential and the resulting electroviscous effects in nanochannels, with adequate considerations of ionic advection due to streaming field induced back electroosmosis, in addition to the pressure-driven ionic transport. In deriving the pertinent equations, it is assumed that the transport phenomena may be described by the continuum conservation equations with appropriate modifications to accommodate special features of interfacial phenomena at small scales. This approach may be adequate for liquid flow systems with characteristic length scales not falling below the order of 1 nm. The fundamental electrokinetic model developed in this work is further utilized to assess the implications of confinement-induced hindered diffusive transport and wall-particle interaction forces (like EDL and van der Waals interactions) on the separation of finite sized charged species in nanochannels. A perturbation-analysis based species transport model is developed to address the unique features of these interaction mechanisms. This model is further enhanced to assess the implications of streaming potential on the transport and separation of finite-sized particles in nanochannels. It is revealed that wall-particle interactions as well as streaming potential effects may play decisive roles towards dictating the resolution of separation, in a manner that is conspicuously contrasting as compared to microchannel based separation. 6 Finally, the effects of streaming potential and confinement induced non-trivial interactions on the dynamics of a flexible polymer molecules in nanochannels are studied in this work. An augmented Brownian dynamics model is developed in order to cater these specific needs. Significant detailed insights are obtained on the implications of nano-scale transport on the center of mass distributions of these polyelectrolyte chains. References 1. Dr. Suman Chakraborty (PhD Thesis Advisor), Professor, Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur. Email: suman@mech.iitkgp.ernet.in Phone : +91-9831402939 (Mobile), +91-3222282990 (Office). 2. Dr. S. K. Som, Professor, Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur. Email: sksom@mech.iitkgp.ernet.in Phone : +91-3222282979 (Residence), +91-3222282978 (Office). 3. Prof. Dr. Detlef Lohse (Postdoctoral Advisor), Chair, Physics of Fluids, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands Email: lohse@tnw.utwente.nl Phone: [31]-53-489-8076, Fax: [31]-53-489-806. 7