ABSTRACTS
WOOD FIRED GLASS FURNACES – HISTORY OR FUTURE?
Bo Jonson, Björn Zethraeus, Växjö University, Sweden
Ruud Beerkens Adriaan Lankhorst, TNO, Holland
Is it possible to use forest residues to gain the energy needed for high temperature industrial
processes and in particular glass melting?
The paper will describe the logistics and characteristics of wood based biofuels. These are
preferable from the perspective of CO2 neutrality, but are they realistic alternative to fossil
fuels?
The results from a pilot project investigating the possibilities to use wood powder combustion
as the energy source in a continuous 50 t/day glass furnace will be reported. It is concluded
that there are promising possibilities, but as well challenges and issues that have to be
addressed and further investigated.
PROCESSING METHODS FOR LEAD CRYSTAL GLASS MANUFACTURING:
PAST, PRESENT, AND FUTURE
Dr. Holly Crawford, Research Associate Professor, Dept. of Agricultural, Resource, and
Food Economics, School of Environmental and Biological Sciences
Dr. Richard L. Lehman, Professor, Dept. of Materials Science and Engineering, School of
Engineering Rutgers, The State University of New Jersey, New Brunswick, New Jersey
The inclusion of lead oxide in glass creates luster and it also generates controversy. In
response, some manufacturers of lead crystal and glass have eliminated lead crystal from their
product lines while others have experimented with reformulations and coatings to minimize or
eliminate lead migration. Other companies have chosen to substitute barium for lead.
This paper examines what the lead crystal industry has accomplished during the past 15 years
with regard to changes in lead crystal manufacturing methods. It further addresses the pros
and cons of these changes (with special emphasis placed on regulatory and economic issues)
and suggests some possible cost-effective and eco-friendly processing methods that can help
manufacturers maintain their lead crystal tradition while maintaining regulatory compliance
and fiscal soundness .
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ACHIEVING LONG LIFETIMES AND EXTREMELY LOW FAILURE RATES FOR
SILICA GLASS OPTICAL FIBRES IN COMMUNICATIONS NETWORKS
Tarja T Volotinen, OFCON Glass and Fibre Consulting AB, Hudiksvall, Sweden
Over billion kilometres of optical fibres have been installed in communications networks
worldwide during the last 29 years. In particular, these fibres in the ocean-, long-distance and
intercity “communication high-way” cables have facilitated the worldwide use of the internet
and mobile-phoning. During the next 20 years optical fibres will reach our homes providing
us with even cheaper and continuous high-capacity connection to the Internet, picturephoning, TV/movies- and conferencing services.
Thus reliability of optical fibres, i.e. a long lifetime (40 years or more) and extremely low
failure rate (of the order of one failure per 105 km fibre distance during 40 years) in service is
required. These requirements can be achieved by using careful material- and manufacturing
control procedures during optical fibre- and cable manufacturing and proper materials, cable
structures and installation methods.
The main service life limiting phenomena will be described: degradation of transmission
properties, fracture of fibre and severe strength degradation (would prevent re-splicing of a
cable cut during excavation). Some interesting historical feedbacks, such as hydrogen based
attenuation increases .and severe strength degradation due to fibre surface corrosion earlier
found in a few optical fibre cables are discussed. Measurement methods for controlling these
problems in installed cable networks are given. These discussions will conclude that optical
fibre lifetime is in practice guaranteed by preventing fractures of fibres, i.e. by controlling the
fibre mechanical quality during fibre and cable manufacturing and after installation.
After that the methods to measure and control the mechanical properties of optical fibres are
described, such as proof testing, strength-, n-value- and B-value measurement methods and
aging test methods for fibres and cables. Lifetime calculation methods are described. Typical
estimated results are compared with the observed fracture frequency in installed cables.
Finally, reliability certification procedures, as well as failure analysis methods for freak
failures (those not statistically frequent enough to take into account in lifetime estimation) are
briefly discussed. The final conclusion is that the worldwide experiences and reliability
estimates are extremely promising. Good quality optical fibres installed in good quality cables
have been seen to be more reliable than can be estimated. Reasons for this are, however, not
fully understood. -The possible reliability issues of due to a high optical power of amplified
multi-wavelength high capacity systems are not discussed.
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METHODS FOR IN-HOUSE RECYCLING OF COLOURED CULLET
Elisabeth Flygt, Glafo, Växj, Sweden
In glass manufacture, there has always been a lot of cullet as waste. In older times, this was in
most cases tipped into a pile at the works. During the past 20 years, all Swedish glassworks
waste has had to be sent to special sites.
During a survey at ten Swedish art and tableware glass works, it was found that about 9000
tonnes of glass are produced. Practically all clear glass except lead crystal was recycled, while
almost all coloured glass was sent to landfill. In 2006, about 950 tonnes of unsorted glass was
sent to landfill.
A large proportion of coloured cullet cannot be recycled today, either because the cullet is not
sufficiently sorted or because it is not known how admixture of the cullet will affect the
quality of the products and production.
Why must glass be recycled? There are several answers, and the first of these is perhaps self
evident. When glass is recycled, natural assets are conserved. Energy is also saved, since less
energy is needed to make glass out of glass. Theoretical calculations indicate a saving of
thirty per cent. The pile of waste is reduced if cullet is used as a resource, and a lot of the cost
of glass raw material and colouring oxides can also be avoided.
In a Glafo project, we have surveyed and analysed cullet from a number of glassworks. This
has given us experience of the re-use of different types of cullet as raw material. On the basis
of this, a number of methods have been formulated in order to help the industry recycle a
major proportion of the cullet that is at present taken to landfill.
The objective was to produce methods that could recycle 75% of the cullet that was sent to
landfill in 2006. It was however found that if the methods produced are applied to the full,
90% of the cullet could be theoretically recycled as raw material.
EASY-TO CLEAN COATINGS ON GLASSES
Minna Piispanen and Leena Hupa, Process Chemistry Centre, Åbo Akademi University,
Turku, Finland
Process Chemistry Centre, Åbo Akademi University, Turku, Finland
The most important results from our research on easy-to-clean and self-cleaning coatings on
flat glass and glazed surfaces will be summarized. The coatings were a hydrophobic
fluoropolymer film and two hydrophilic surfaces. The hydrophilic surfaces were a sol-gel
derived titania on glass and a hybrid surface consisting of titania and silver particles applied
on the glass through liquid flame spraying. The effects of the coatings on the surface
appearance, surface roughness as well as soil attachment and removal will be discussed.
Additionally, the chemical resistance and mechanical durability of the surfaces in acid to
alkaline water solutions and cleaning agents are described.
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NATURAL GAS, SAFE AND ENVIRONMENTALLY FRIENDLY FUEL
Arto Riikonen, Gasum Oy, Finland
The presentation consists of
- general information on natural gas use in Finland
- supply security, more than 30 years of experience
- safety aspects of natural gas use
MEASURING THE ION DISSOLUTION FROM GLASSES
Susanne Taipale, Paul Ek and Leena Hupa, Process Chemistry Centre, Åbo Akademi
University, Turku, Finland
Continuous measurement of leaching kinetics and chemical resistance of glasses in aqueous
environments is reported. The measuring system consists of a flow-through-reactor in which
the aqueous solution is fed through a bed of glass particles and the dissolved ions are recorded
with an on-line analysis system. Experimental parameters, such as solution flow rate and
temperature, can easily be adjusted according to the needs. The analysis system was used to
estimate the early stage ion release as well as the steady the leaching of float glass, E-glass
and tableware glasses containing different colouring ions. Also, glasses with a high
dissolution rate, such as bioactive glasses were tested. Besides the overall chemical resistance
also accurate information on concentrations of the ions leached from the glasses was gained.
OPTICAL AND THERMAL PROPERTIES OF FUNCTIONAL GLAZING FOR
HIGH PERFORMANCE WINDOWS
Annica Nilsson and Arne Roos, The Ångström Laboratory, Uppsala University, Box 534,
SE-751 21 Uppsala, Sweden
Low-emissivity coatings for solar and thermal control by modern windows have led to a
revolution in window technology. With emissivity values below 0.05 windows with U-values
well below 1 W/m2K can readily be manufactured. Solar control coatings with double silver
layers completely block the near infrared solar radiation and transmit visible light.
Antireflective coatings can be used to further improve the optical properties. Hydrophilic and
photo-catalytic coatings on the external surface help to remove dirt and dust and also to
reduce the effect of external condensation. The next generation of window coatings includes
switchable glazing, such as electrochromic coatings. Such coatings can switch between a
transparent state and an absorbing or reflecting state in order to adapt the optical properties to
the present need of the building. Thus, the traditional window is more and more becoming an
integral part of the building’s energy system. This presentation is a short overview of the solar
and thermal properties of some of these coated glazing products.
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NONLINEAR MODELLING OF VISCOSITY OF STONE WOOLS OF DIFFERENT
COMPOSITIONS
Abhay Bulsari, Nonlinear Solutions Oy, Finland
Niklas Bergman and Pontus Lindberg, Paroc Group Oy Ab, Finland
Viscosity of glassy materials is of interest to industries of several different products including
stone wools, where a better control over viscosity can significantly help in improving the
fiberising process. There have been attempts to develop models predicting the viscosities of
glass at given temperatures, or for predicting the temperatures at which the viscosity reaches
certain values. Such models have been based on linear regression, sometimes with one
nonlinear term like the reciprocal of temperature.
This work shows that new techniques of nonlinear modelling which are based on free-form
nonlinearities are better capable of predicting the viscosities, and take into account the
nonlinearities in the effects of composition variables. Data was available from 52 different
compositions. A nonlinear model predicting the logarithm of viscosity results in a correlation
coefficient of over 92%. The effects of silica, lime and alumina contents on logarithm of
viscosity show moderately strong nonlinearities.
MECHANICAL AND ADHESIVE JOINTS IN STRUCTURAL GLASS
Kent Persson, Inst. of Construction Sciences, Lund University, Lund, Sweden
From an aesthetic and architectonic perspective the use of transparent glass elements in the
structural system creates a very pleasant, light and airy internal environment, which are in line
with modern demands of light and slender constructions. A key issue when using glass as a
building material that also have a load-carrying capacity is how to incorporate the glass into
the building construction i.e. how to make joints between glass panes and between glass and
other materials in the building structure. In this paper, experimental measurements and
analysis of the stiffness, deformation and strength of mechanical point fixings and adhesive
joints in glass will be presented. Commonly, glass is joined by mechanical point fixings but
since glass is a brittle material that is sensitive to stress concentrations it may be beneficial to
use adhesive joints.
CASE STUDY: ESTONIAN MONUMENT OF THE WAR OF INDEPENDENCE –
GLASS IN MONUMENTAL ART
Rainer Sternfeld, Sternfeld & Laidre Ltd., Estonia
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