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- ItemHat sich Georgius Agricola in seiner Abhandlung über Glaserzeugung am Ende seines Werkes „De re metallica" geirrt?(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Broul, Julius[no abstract available]
- ItemOpen-pore sintered glass-ceramics as carrier material for biotechnological use(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Gemeinert, Marion; Müller, Ralf; Wihsmann, Fred Gustav; Schröder, Frank; Kliche, HorstOpen-pore carriers with defined open porosity up to 45 % for biotechnological use were manufactured by sintering and crystallization of glass powders of cordierite stoichiometry. The stop of the shrinkage caused by a surface crystallization of the glass ("sinter blockade") is utilized to stabilize a desired pore volume without filier or foaming aids. Glass powders of the stoichiometric composition of cordierite (2MgO · 2AI₂O₃ · 5SiO₂) with different grain size distributions were used as starting materials. The efficiency of the sinter blockade and thereby the stabilized porosity of the resulting compact mainly depends on the surface nucleation density at the Single glass particles which can be adjusted by powder processing. Furtheron, the chosen grain size distribution of the glass powders and the sintering process parameters (heating rate, temperature, heating time) are important factors to control the sintering behaviour. Samples of carrier bodies produced by this way are tested and evaluated quantitatively as carriers for biofilms in a biotechnological process for decomposition of pollutants in a synthetic model waste water system.
- ItemRatio of CaO/K20 > 2 as evidence of a special Rhenish type of medieval stained glass(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Müller, Wolfgang; Toge, Manfred; Adam, KarinThe chemical compositions of more than 300 medieval stained glass samples of different local origin have been published so far. Regarding their characteristic components they can be classified into five types. About 80 % of all investigated samples proved to be potash-lime-silica glasses with roughly equal concentration of CaO and K₂O (type 1). But a small group of little more than 20 samples gave a ratio of CaO/K₂0 > 2 (type 2), all but three of which had been taken from two churches of the Rhine region (St. Catherine Church Oppenheim and Cologne Cathedral). Hence, it seems likely that a corresponding recipe was used there, which was nearly unknown elsewhere in Europe. Investigation of further objects of this region might be of interest for the history of technology.
- ItemLow-temperature tensile deformation of flat glass containing metal particles to generate dichroism(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Borek, Reinhard; Berg, Klaus-Jürgen; Berg, GunnarUniformly oriented metal particles shaped like prolate spheroids are produced by tensile deformation of flat glasses, containing small spherical particles of some 10 nm in diameters. The deformation is performed at temperatures only slightly above Tg. High tensile stresses up to 200 N/mm² and low velocities of deformation characterize the special conditions of this process. The method has been improved such as to exceed the previous limitation to relatively small values of the cross section of the specimens. Α unidimensional hydromechanical model including the conservation equations for momentum, mass and energy describes the glass deformation. The model has been solved numerically Α good agreement has been attained between experimental and theoretical results.
- ItemBioactive coatings of glass-ceramics on metals(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Jana, Carsten; Wange, Peter; Grimm, Gabriele; Götz, Wolfgang; Nisch, WilfriedTo combine the mechanical properties of high-strength base metals with the biological properties of bioactive materials, coatings of BIOVERIT® glasses and glass-ceramics on CoCr alloys and titanium have been produced. Different kinds of coating processes have been used: dipping, sputtering, plasma spraying, sintering and pasting. Dipping and pasting seem not to be suitable to produce layers because of cracks and low adhesion strength of the coatings (dipping) and the limitations in relation to the implant shape and the thickness of the layers (pasting). Using sputter techniques it is possible to produce dense layers ( < 10µim) with a high adhesion strength. Plasma spraying resuhed in layers with a thickness of 50 to 300µim, but during the plasma spraying process there is a partial evaporation of the highly volatile glass components. Sintering processes are very suitable to produce layers with a high adhesion strength; these layers are long term stable in simulated body fluid.
- ItemGlass with super thermal insulation properties. An important element in the fight to reduce heat consumption in buildings(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Ortmanns, GünterThe application of heat-insulating glasses gives rise to the preservation of fossil energy and thus represents an important contribution for energy savings. Since many years the glass industry provides highly efficient insulating glass systems with low U values as well as with various solar transmissions. These systems have a strong impact on an architecture which cares for the aspect of ecology. The glass industry is well-prepared with the heat-insulating glasses to meet the pending regulations for heating of buildings. These new glass products have been introduced already. Furthermore, the glass industry is prepared to adjust to the capacity requirements as a consequence of further standardization by providing neutral, highly transparent, coated insulating glasses. In particular the paper deals with the solar contribution to the heating of buildings, the state of art in the manufacturing of heat-insulating glasses with low-emissivity coatings and gas filling, and the influence of the window on the heat requirement of buildings.
- ItemThermal behavior of metallic aluminum in a Container glass melt(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Reisch, Renate; Stachel, Dörte; Traufelder, Steffi; Tessmann, ElkeThe thermal behavior o f metallic aluminum was studied in the temperature ränge of 1100 to 1500°C in a Container glass melt. The dissolution of the metal was determined as a function of aluminum input, glass volume, melting time and the type of glass used. By analogy, melts containing magnesium cuttings were also investigated. With the aid of electron microscopy, it was possible to establish a reaction scheme of Oxidation and reduction processes. Only 2 to 3 % of the aluminum introduced causes the formation of silicon spheres. The main part will be oxidized through reactions with oxygen, hydroxide and polyvalent ions in the melt.
- ItemRecycling of refractories from the glass manufacturing industry(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Dunkl, MichaelRefractories present at the end of campaigns of glass melting furnaces are to a large part corroded, infiltrated by glass and/or have reacted to its components. In addition to the refractories heavily contaminated by melted glass and its vaporized or condensated by-products, other refractories are retrieved, often in large quantities, which are only Hghtly contaminated or not at all. Up to now the larger amount of refractories remaining after furnace campaigns have been disposed of and only a relatively small amount re used in the refractory industry (approximately 10%). Recycling of this material is, however, legally imperative, and various lightly contaminated refractories are now being recycled by some companies for re-use as refractories as well as for other applications. This paper will discuss the present situation of recycling refractories retrieved from glass melting furnaces by the glass and refractories industries with the aim of initiating the problem solving process. Based on a recent inventory it will be shown which quantities of which types of refractory materials occur in the German glass industry and with which impurities the refractories can be contaminated. Using a qualitative presentation of the impurities present in the refractories retrieved from different parts of the furnace and different types of glasses, various possibilities for recycling will be discussed. Not yet existant, basic requirements and the necessity of corresponding research will be indicated. Successful and far-reaching solutions of these problems must be the common goal of the glass and refractory industries.
- ItemNondestructive analysis of potassium in ancient glass on the base of its natural gamma activity(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Kunicki-Goldfinger, Jerzy J.; Kierzek, JoachimThe concentration of K₂O in historical glass objects was measured by gamma ray spectrometry. The method involved using moulds of the objects filled with material of known K₂O content. The results obtained were found to be close to results previously obtained by traditional methods and well within accepted tolerances in such cases. Gamma ray spectrometry produces results based on the whole object, not just on a sample of it which in the case of historical glass may not be representative. The method is completely nondestructive as no sample is taken, which allows it to be used for museum glass when destrucdon may not be permitted.
- ItemUltrasonic determination of the residual wall thickness of glass furnace refractories(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Fleischmann, BernhardThe determination of the corrosion progress of refractory blocks on operating glass furnaces is of great interest to the glass industry. Several European glass research Institutes collaborated within the European SPRINT programme to develop an ultrasonic method of measuring the residual thickness of refractory blocks. The experience of the Hüttentechnische Vereinigung der Deutschen Glasindustrie and the TNO Institute of Applied Physics in the field of ultrasonic testing of materials as well as high-temperature applications of ultrasound were used to develop a device that was tested under laboratory conditions and in first industrial tests. After scaling up the equipment a number of industrial measurements were carried out on different furnace types in Europe. These tests showed that reliable results can be obtained with this device.