67 results
Search Results
Now showing 1 - 10 of 67
- ItemShort Communication: the Influence of Air-Abrasive Trimming on the Current Noise of Thick Film Resistors(London [u.a.] : Gordon & Breach, 1984) Wolf, M.[No abstract available]
- ItemOn Experimental Data of the Tcr of Tfrs and Their Relation to Theoretical Models of Conduction Mechanism(London [u.a.] : Gordon & Breach, 1985) Storbeck, I.; Wolf, M.Any theory of electrical conduction in TFRs encounters mainly two problems: (i) explanation of the dependence of R□ on properties of conducting component (volume fraction, grain size, resistivity), (ii) explanation of the temperature dependence of R□ taking into account (i). In order to achieve this one has to fit some microscopic parameters to experimental R□-and TCR-values, and to check if they are reasonable or not. The aim of the following discussion is to show, that such a fitting by means of experimental TCR-values is not correct. This is due to the fact that TCR-behaviour, as is well known, is determined also by the dependence of resistivity on strain. But any theoretical model neglects strains, also those who are induced by thermal strains. By means of published experiments concerning the strain dependence of resistance, the magnitude is estimated by which the TCR-values have to be corrected for the described fit.
- ItemNew German development for ΝΟx removal from waste gases - Preliminary results and prospects(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Danowski, Friedhelm; Koschlig, Hans-Joachim; Hutter, Frank; Schmidt, HelmutThe process of manufacturing and test results of a new catalyst for the selective catalytic reduction of nitrogen oxides are presented. The catalyst is prepared by a special coating process of a multicomponent sol on top of a porous cordierite honeycomb structure. The catalytically active system is based on a mixture of TiO2, V2O5 and WO3. Laboratory and industrial tests were carried out.
- ItemGlass improvement by combination with plastics(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Jandeleit, OttoAfter a short survey of the development of laminated safety glass, modern safety and comfort requirements are listed. Problems and properties of such glass-plastic combinations are examplified by the Sekuriflex windshield. In addition, other functions and solutions for security glazings as well as antifogging by moisture and impact resistance are discussed. Fireproof and sound insulating glazings are discussed on the basis of symmetrical glass-plastic combinations with both exterior faces consisting of glass.
- ItemObservations on the process and the products of chemically tempered glass(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Paudice, Ciro; Boattini, Pier Paolo; Bergia, Lucia[no abstract available]
- ItemSintering behaviour of submicron silica particles(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Clasen, RolfThe sintering process is the final step in the preparation of transparent silica glass via a powder ceramic route starting from fumed silica glass powder. As high green densities can be obtained with this method the shrinkage during drying and sintering is small and compacts like rods and tubes can be easily prepared. The study of the sintering behaviour of these compacts made from submicron particles was based on two aspects, namely that of the parameters influencing the sintering rate of the sample (macroscopic behaviour) and that of the interaction between single particles (microscopic behaviour). The sintering rate depends on the furnace temperature and the thermal conductivity of the sample. As the thermal conductivity in the sintered silica glass is about two orders of magnitude higher than in the porous compact, a dominant axial heat flux during zone sintering should be expected. This could be experimentally confirmed by measuring the sintering behaviour of rods and tubes and making the isotherms of the samples in the sintering zone visible. The viscous flow of single particles was measured by the decrease of the surface area of the compact during sintering. As the correspondence with calculations based on known models was not sufficient and no interpretation of the deviations was possible, new calculations were performed based on an improved Frenkel model. Due to the close approximation of this model to the spherical particles, the differences of model calculations and measurements with increasing sintering time could be interpreted by agglomerates in the compacts.
- ItemGlass-ceramics of the system Pb(Zr0.5Ti0.5)O3-GeO2(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Park, Won-Kyu; Yamane, MasayukiΑ thin film of glass-ceramics containing Pb(Zr0.5Ti0.5)O3 has been prepared by rapid quenching of a melt of the system Pb(Zr0.5Ti0.5)O3-GeO2 and subsequent heat treatment for crystallization. The dielectric constant of the glass-ceramics obtained by the heat treatment at 1000 °C for 2 h ranged from 96 to 123. An endothermic peak which is considered to show the ferroelectric-paraelectric transition was observed between 420 and 445 °C on the DTA curve of the glass-ceramics.
- ItemGlas im Bauwesen - CEN-Arbeit(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Bahlo-Dittmann, Käthe[no abstract available]
- ItemManufacture, properties and application of open-pore sintered glasses and open-pore sintered glass-ceramics(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Siebers, Friedrich B.; Greulich, Norbert; Kiefer, WernerΑ new process was developed for the manufacture of open-pore sintered glass and glass-ceramics with defined porosity according to the filler principle. Fine-grained glass powder is homogeneously mixed with an inorganic salt of specified grain size and sintered. The salt is washed out, its grain size allowing the adjustment of the mean pore diameter between 5 and 350 μm accompanied by a sharp pore size distribution. The quantity of inorganic salt determines the open pore volume between 20 and 80 vol%. The manufacture of an open-pore sintered glass-ceramic requires a crystallizable glass powder. Depending on the choice of glass powder and inorganic salt compositions inert behavior can be maintained, or ion exchange takes place leading to new compositions and properties. Properties are a consequence of defined porosity and the microstructure of the skeleton material. Maximum working temperatures may reach about 750 °C in the case of sintered glasses and up to 1400 °C in the case of sintered glass-ceramics. The application of the open-pore materials results from their selectively adjustable porosity: filtration of gases and liquids; separating processes; storage, conduction and distribution of liquids; electric and thermal insulation; catalyst carriers; biotechnology.
- ItemThermochemical study of the liquid systems BaO-B2O3 and CaO-B2O3(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Müller, Franz; Demirok, SuatThe integral molar enthalpy of mixing of the liquid mixtures BaO-B2O3 and CaO-B2O3 was measured calorimetrically in the composition range from about 30 to 100 mol% B2O3 at temperatures of 1551 and 1725 K, respectively, and the partial molar enthalpy of mixing of the component oxides was obtained by the method of intercepts. The curves representing the functional dependence of the integral and partial enthalpy of mixing on composition are composed of three distinct sections separated one from the other by "singularities" (points of inflection, maxima, etc.). The possible significance of this as well as the relationship between the thermochemical and structural properties of the liquid mixtures are discussed on the basis of information, reported for the structure of these mixtures in the literature.