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- ItemElektrisch beheizte Glasschmelzöfen - Heutiger Stand vor dem Hintergrund Energie, Umwelt, Flexibilität und Betriebssicherheit Teil 2(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Voss, Hans-JörgBeim elektrischen Glasschmelzen muß der Wechselwirkung zwischen Schmelze und umgebendem Feuerfestmaterial als möglicher Quelle von Glasfehlern besondere Aufmerksamkeit geschenkt werden. Es werden Vorgänge beleuchtet, die sowohl die Betriebssicherheit als auch die Verfügbarkeit einer Glasschmelzanlage mit Elektrodenbeheizung beeinträchtigen können. Korrosion von Molybdänelektroden und ihre Verringerung durch elektrochemische Maßnahmen, neue Elektrodenwerkstoffe und Schutzschichten werden besprochen. Das weite Feld unterschiedlicher Wannentypen für die vollelektrische Glasschmelze, die bewußte Trennung der Verfahrensschritte beim Glasschmelz- und -läuterprozeß sowie Sonderformen der Glasschmelze werden erläutert.
- ItemStand des Altglasrecyclings - Verpackungsverordnung und Duales System(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Hoffmann, Werner[no abstract available]
- ItemRecent investigations of early Roman cameo glass : Part 2. X-ray fluorescence analyses induced by Synchrotron radiation(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Mommsen, Hans; Brüning, Axel; Dittmann, Heiko; Hein, Anna; Rosenberg, Achim; Sarrazin, GuidoThe elemental composition of 14 Roman cameo glass fragments was measured quantitatively b y X-ray fluorescence analysis induced by synchrotron radiation. The study was intended to learn more about the possible manufacturing techniques of these glasses. In the white cameo decor of nine fragments all belonging to vessels a higher lead oxide concentration was detected compared to the colored body. In contrast, lead oxide is not enhanced in the remaining five fragments from cameo disks or plates. The higher concentrations may be interpreted as flux added to lower the melting temperature of the white cameo layers of the vessels, thus supporting the recent hypothesis that these cameo vessels were manufactured with the help of a mold on a turning wheel, which had not to be used for the production of cameo plates.
- ItemMethod for determining in-vitro dissolution rates of man-made vitreous fibres(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Guldberg, Marianne; Christensen, Vermund R.; Krøis, Winni; Sebastian, KlausA "state-of-the-art" method for determining the in-vitro dissolution rate of man-made vitreous fibres (MMVF) is described. The dissolution rate is determined using an artificial lung fluid, adjusted to pH values of 7.5 or of 4.5, reflecting that the dissolution in vivo takes place both in the near-neutral lung fluid and in the acidic environment of the macrophages. The method is based on flow-through equipment and prescribes well-defined conditions using a ratio of the flow rate to surface area of 0.03 µm/s. The results obtained with this method correlate to results from in-vivo tests, and thus the method provides a tool for a comparative evaluation of the biodurability of different fibre types. The described method seems suitable to be estabhshed as a provisional standard test, until further investigations allow the definition of a final standard test. The empirically derived carcinogenicity index (KI) extrapolates the in-vitro results obtained for some fibre types at the neutral pH value to other very different fibre types. The proposed in-vitro method avoids these uncertain generalizations, as it is based on actually measured dissolution rates at pH values 7.5 and 4.5, respectively.
- ItemEvaluation of reaction rate of refining agents(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Kawachi, Shinji; Kato, Mitsuo; Kawase, YoshinoriTo elucidate the thermal decomposition behavior of antimony oxide which is added to promote (re)fming of bubbles in TV glass, an evolved gas analysis (EGA) was conducted using a newly designed device for detecting the gases from the glass batch at increasing temperatures. Furthermore, a mathematical formulation was made to describe the above behavior. From the results of the EGA measurements, three parameters, which govern the reaction rate constant, viz. reaction order, activation energy and frequency factor, were decided. By coupling this mathematical model and the thermal fluid model of glass melts in tank furnaces, it is possible to simulate the conditions of generating refming oxygen in the furnace.
- ItemIn-situ-Verfahren zur Klassifikation von Glasfehlern(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Berndt, Dirk[no abstract available]
- ItemBorosilicate glass matrix composites reinforced with short metal fibres(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Boccaccini, Aldo R.; Ondracek, Gerhard; Syhre, ClaudiaThe reinforcement of a borosihcate glass with Hastelloy X short fibres is discussed. A fabrication process consisting of wet mixing of the glass powder and the metallic fibres and hot pressing of the mixtures was developed. Composites containing 15 vol.% fibres homogeneously distributed in a near fully dense glass matrix were obtained. Both Young's modulus and fracture strength increased with increasing volume fraction of fibres. The experimental values for the Young's modulus are in agreement with theoretical predictions. No fibre pull-out during fracture was detected and there is a good interfacial bond. By means of a rule-of-mixture calculation for the fracture energy, a five-fold increase in fracture toughness for composites containing 15 vol.% fibres can be predicted.
- ItemGlass industry and glass research in China - Brief overview(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Fan, Su Jian[no abstract available]
- ItemThe firing of enamels onto borosilicate glass through the selective absorption of infrared radiation(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Lochner, Karl Heinz; Böhm, ThureGradations and other markings on laboratory glassware are made mainly with glass enamels. Firing temperatures of around 600 °C (i.e. 70 to 80 Κ above the transformation temperature of the glass) are needed in order to reach sufficient chemical and mechanical resistance. This can lead to alterations in the volume of the flasks. Due to the uneven temperature distribution in continuous or batch furnaces some flasks may undergo a volume change that is greater than the accepted margin of error of the calibration. The aim of this study was to find a firing process for glass enamels that ensures the same chemical resistance as the furnace firing but without the risk of changing the volume. This was obtained by a combination of conventional heating by a hot-air blower and selective heating by absorption of infrared radiation. Α halogen lamp and an Nd-YAG laser were used as infra-red sources. The use of the laser clearly showed better results. By firing-on blue lead-enamel with a laser a chemical and mechanical resistance comparable to that of furnace firing was achieved without altering the volume of the measuring Container.
- ItemMechanism of volatilization of fluorides from E-glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Pentzel, Constanze[no abstract available]