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81.
Benjamin Bock Anne Schmidt Edyta Sniezek Steffen Dudczig Gert Schmidt Jacek Szczerba Christos G. Aneziris 《Ceramics International》2019,45(4):4499-4508
Since solid, non-metallic inclusions influence considerably the quality of casted steel products, carbon-bonded alumina foam filters are used in secondary metallurgical treatments to remove these particles from steel melts. In order to attain a significant improvement of the filtration process, five different carbonaceous spinel compounds from the Fe-/Mg-/Mn-Al-O systems are applied on carbon-bonded alumina filters in this study and investigated with regard of their filtration efficiency. However, these spinel compounds decompose partially during sintering at 1400?°C under reducing atmosphere, wherefore the resulting coatings contain not only spinel compounds, but also oxidic and metallic components. The subsequent interaction with molten steel leads to the development of multicrystal structures on the filter surface, which stem from interfacial reactions between coating materials, molten steel, and inclusions. As a result of this procedure, a reduction of almost 60% alumina inclusions is measured with the aid of an automatic SEM, whereby spinel compounds from the Fe-Mn-Al-O system achieve highest filtration efficiencies. 相似文献
82.
Simutin A. N. Deineko A. V. Zertsalov M. G. 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2021,55(4):482-486
Power Technology and Engineering - The monitoring of hydraulic structures as high-risk facilities is discussed. Monitoring should ensure the reliability and functioning of a hydraulic structure... 相似文献
83.
G. Stanciu L. Gheorghe F. Voicu S. Hau C. Gheorghe G. Croitoru M. Enculescu R.P. Yavetskiy 《Ceramics International》2019,45(3):3217-3222
(Y0.87-xLa0.1Zr0.03Ybx)2O3 (x?=?0.02, 0.04, 0.05) transparent ceramics were obtained by solid-state reaction and combined sintering procedures with La2O3 and ZrO2 as sintering additives. A method based on two-step intermediate sintering in air followed by vacuum sintering was applied in order to control the densification and grain growth of the samples during the final sintering process. The results indicate that La2O3 and ZrO2 co-additives can improve the microstructure and optical properties of Yb:Y2O3 ceramics at relatively low sintering temperature. On the other hand, the addition of Zr4+ ions leads to the formation of dispersed scattering volumes in the ceramic bodies. Transmittance of 78.8% was measured for the 2.0?at% Yb:Y2O3 ceramic sample at the wavelength of 1100?nm. The spectroscopic properties of Yb:Y2O3 ceramics were investigated at room temperature. The obtained results show that the absorption cross-section at 978?nm is in the range of 2.08?×?10–20 to 2.36?×?10–20 cm2, whereas the emission cross-section at 1032?nm is ~1.0?×?10–20 cm2. 相似文献
84.
S.V. Stefanovsky A.G. Ptashkin I.A. Knyazev O.I. Stefanovsky S.V. Yudintsev B.S. Nikonov B.F. Myasoedov 《Ceramics International》2019,45(3):3518-3521
La-Ce-Gd titanate-zirconate pyrochlore-based ceramics was synthesized at the lab-scale inductive melting unit with a 56?mm inner diameter cold crucible. Batch feeding rate and melting ratio were 3?kg/h and 3?kW?h/kg respectively. The ceramics is composed of 85–90?vol% zoned grains of the pyrochlore structure phase, the sample has excellent chemical durability in hot water and may be considered as a promising matrix for actinide – rare earth fraction of high level waste. 相似文献
85.
Gülsün Özyurt Ali Serhat Özkütük Yılmaz Uçar Mustafa Durmuş Yesim Ozogul 《International Journal of Food Science & Technology》2019,54(4):1081-1088
Waste or by-products contains a substantial amount of nutrients. Fish silage is an alternative way for assessment of fish discards and waste generated in the fish processing industries. The aim of the study was to evaluate the potential use of discard species (Equulites klunzingeri, marine fish and Carassius gibelio, freshwater fish) for fish silage and chemical quality of fish oil extracted from fish silages prepared with acid and fermented methods. Lipid quality of fish oils extracted from fish silages with LAB strains was evaluated in terms of thiobarbituric acid (TBA), peroxide value (PV), p-Anisidine (AV), totox values and fatty acid composition. The results showed that PV, TBA, AV and totox values of all extracted fish oils were within the acceptable limits for edible oils. Recovered fish oils from silage contained high level of polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), serving as a source of good quality fish oil for human consumption. 相似文献
86.
Rita Głowacka Agata Górska Magdalena Wirkowska-Wojdyła Rafał Wołosiak Ewa Majewska Dorota Derewiaka 《International Journal of Food Science & Technology》2019,54(11):3008-3014
The content of bioactive compounds in spent coffee grounds (SGC) was studied. SGC were obtained from Coffea arabica beans of different roasting degrees (light and dark) and different geographical origins (Nicaragua, Columbia and Mexico) processed using four brewing methods (mocha, filtered, drip and infusion). The highest caffeine and chlorogenic acid contents were determined in filtered spent coffee extracts. All extracts of light roasted spent coffee grounds showed lower browning index levels in comparison to that from dark roasted spent coffee grounds. Generally, the highest content of total polyphenolic compounds and highest antioxidant capacity were determined in extracts prepared in drip. In conclusion, the results obtained in this study indicate that the spent coffee grounds produced of domestic levels, especially those obtained from filter coffeemaker, could be considered as a good source of natural antioxidants. 相似文献
87.
Ryan J. Grohsmeyer Laura Silvestroni Gregory E. Hilmas Fredêric Monteverde William G. Fahrenholtz Andrea D’Angió Diletta Sciti 《Journal of the European Ceramic Society》2019,39(6):1948-1954
The mechanical behavior of ZrB2-MoSi2 ceramics made of ZrB2 powder with three different particle sizes and MoSi2 additions from 5 to 70 vol% was characterized up to 1500 °C. Microhardness (12–17 GPa), Young’s modulus (450–540 GPa) and shear modulus (190–240 GPa) decreased with both increasing MoSi2 content and with decreasing ZrB2 grain size. Room temperature fracture toughness was unaffected by grain size or silicide content, whilst at 1500 °C in air it increased with MoSi2 and ZrB2 grain size, from 4.1 to 8.7 MPa m½. Room temperature strength did not trend with MoSi2 content, but increased with decreasing ZrB2 grain size from 440 to 590 MPa for the largest starting particle size to 700–800 MPa for the finest due to the decreasing size of surface grain pullout. At 1500 °C, flexure strength for ZrB2 with MoSi2 contents above 25 vol% were roughly constant, 400–450 MPa, whilst for lower content strength was controlled by oxidation damages. Strength for compositions made using fine and medium ZrB2 powders increased with increasing MoSi2 content, 250–450 MPa. Ceramics made with coarse ZrB2 displayed the highest strengths, which decreased with increasing MoSi2 content from 600 to 450 MPa. 相似文献
88.
Di An Wei Liu Zhipeng Xie Hezhen Li Xudong Luo Haidong Wu Meipeng Huang Jianwei Liang Zhuo Tian Rongxuan He 《Journal of the American Ceramic Society》2019,102(5):2263-2271
In this study, we developed a unique defect healing method for 3D printed ceramic compact via cold isostatic pressing (CIP) after debinding, and typical features of interlayer interface defects of 3D-printed zirconia compact were characterized and found to be reduced significantly. The characteristic sintering kinetics window and microstructure evolution of the healed sintered bodies were systematically investigated, which was found to be quite different from conventional shaping methods. The three sintering stages are probed by their feature microstructure details such as the mechanically flattening surface at the early sintering stage, the heterogeneous microstructure and high porosity in the interlayer interface region at the middle stage, and the slightly ripple-like structural features combined with the healed interlayer defects at the final stage. The evolution of the pore structure of the healed 3D printed bodies were traced and the mechanical properties such as the Young's modulus, hardness, and fracture toughness were measured to understand the significance of the heal effect. 相似文献
89.
Thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing behaviors of such kind of fluid on a heated surface have been rarely explored. In this study, we experimentally and numerically investigated the spreading and curing behaviors of the silicone(OE6550 A/B, which is widely used in the light-emitting diode packaging) droplet with diameter of ~2.2 mm on a heated surface with temperature ranging from 25 ℃ to 250 ℃. For the experiments, we established a setup with high-speed camera and heating unit to capture the fast spreading process of the silicone droplet on the heated surface. For the numerical simulation, we built a viscosity model of the silicone by using the Kiuna's model and combined the viscosity model with the Volume of Fluid(VOF) model by the User Defined Function(UDF) method. The results show that the surface temperature significantly affected the spreading behaviors of the silicone droplet since it determines the temperature and viscosity distribution inside the droplet. For surface temperature varied from 25 ℃ to 250 ℃, the final contact radius changed from ~2.95 mm to ~1.78 mm and the total spreading time changed from ~511 s to ~0.15 s. By further analyzing the viscosity evolution of the droplet, we found that the decreasing of the total spreading time was caused by the decrease of the viscosity under high surface temperature at initial spreading stage, while the reduction of the final contact radius was caused by the curing of the precursor film. This study supplies a strategy to tuning the spreading and curing behavior of silicone by imposing high surface temperature, which is of great importance to the electronic packaging. 相似文献
90.
Chandran Senthilkumar John James G. Rajesh P. 《Journal of Materials Science: Materials in Electronics》2021,32(15):20362-20373
Journal of Materials Science: Materials in Electronics - The single crystals of pure and 1 mol% Co2+-doped sodium acid phthalate hemihydrate were grown by slow evaporation solution growth... 相似文献