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991.
Interaction of slip‐ and flame‐spray coated carbon‐bonded alumina filters with steel melts 下载免费PDF全文
Patrick Gehre Anne Schmidt Steffen Dudczig Jana Hubálková Christos G. Aneziris Nick Child Ian Delaney Gilbert Rancoule Duane DeBastiani 《Journal of the American Ceramic Society》2018,101(7):3222-3233
Ceramic foam filters play an essential role in the quest for cleanliness of cast steel parts as they facilitate turbulence reduction during mold filling as well as removal of nonmetallic inclusions. A coating on these filters is able to increase their strength and filtration efficiency by improving the adhesion of inclusions to the filter strands. In this study, Al2O3‐C filters were coated with an alumina slip via slip and flame spraying. The phase composition and the microstructure of the coatings were investigated before and after immersion into molten steel contained in a metal casting simulator. After contact with molten steel, Al2O3‐C reference filter shows intense decarburization which often influence the quality of cast steel parts due to formation of gas bubbles. Slip‐sprayed alumina coatings on such a filter promote the deposition of inclusions due to formation of a vitreous alumina layer but will also cause gas bubble formation as they exhibit a high porosity. Flame‐spray coatings have low porosity and hence, prevent formation of gas bubbles. Furthermore, they showed the highest reactivity toward the steel melt and hence, are recommended for filtration of cast products with a high demand on cleanliness. 相似文献
992.
Andreas Otto Stefan Rauh Steffen Ihlenfeldt Günter Radons 《The International Journal of Advanced Manufacturing Technology》2017,89(9-12):2613-2625
We study mechanical vibrations in milling with non-uniform pitch and variable helix tools. The process is modeled by a periodic delay differential equation with distributed delay, which takes into account, for example, the nonlinear cutting force behavior, the effect of runout, and the exact delay distribution due to the unequally spaced flutes. We present a new method for the identification of the chatter stability lobes from the linearized system that is based on the multifrequency solution. We give detailed remarks on the truncation of the resulting infinite dimensional matrices and the efficient numerical implementation of the method. Cutting tests for steel milling with a customary end mill with non-uniform pitch and variable helix angle and a conventional end mill with uniform pitch and constant helix angle are performed. The numerical and experimental results coincide well. They reveal a significant increase of the limiting depth of cut for the variable helix tool compared to the conventional tool. Moreover, we show that in contrast to conventional tools, for non-uniform pitch and variable helix tools, an exact model with time-varying coefficients, nonlinear cutting force behavior, and runout is necessary for an accurate prediction of the stability lobes. 相似文献
993.
Fabrication of a transversal multilayer thermoelectric generator with substituted calcium manganite 下载免费PDF全文
Timmy Reimann Arne Bochmann Andy Vogel Beate Capraro Steffen Teichert Jörg Töpfer 《Journal of the American Ceramic Society》2017,100(12):5700-5708
The sintering behavior and thermoelectric performance of Ca0.99Gd0.01Mn0.99W0.01O3 was studied, and a multilayer thermoelectric generator was fabricated. The addition of CuO as sintering additive was found to be effective for the reduction in the sintering temperature from 1300°C to about 1000°C‐1050°C. Dense samples were obtained after firing at 1050°C, whereas some porosity remained after firing at 1000°C. Samples sintered at reduced temperature exhibit lower electrical conductivity, whereas the Seebeck coefficient S = ?150 μV/K at 100°C is not affected by lowering the sintering temperature. The figure of merit is ZT = 0.12 at 700°C for samples sintered at 1300°C; ZT = 0.08 and 0.03 were obtained for multilayer laminates sintered at 1050°C and 1000°C, respectively. A transversal multilayer thermoelectric generator (TMLTEG) was built by stacking layers of substituted CaMnO3 green tapes, and printing AgPd conductor stripes onto the thermoelectric layers at an angle of 30° relative to the direction of the heat flow. The multilayer stack was co‐fired at 1000°C. The TMLTEG has a power output of 2.5 mW at ?T= 200 K in the temperature interval of 25°C‐300°C. A meander‐like generator with larger power output comprising six TMTEGs is also presented. 相似文献
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Robert Braunsdorf Uwe Hener Gaby Przibilla Steffen Piecha und Armin Mosandl 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1993,197(1):24-28
Zusammenfassung Der Einfluß chromatographischer und technologischer Verfahren auf den13C-Isotopengehalt aromarelevanter Substanzen in Orangenölen wird untersucht. Um Fehlinterpretationen von Isotopendaten auszuschließen, muß eine effektive, verlustfreie Probenaufbereitung sichergestellt werden. Während bei der Verarbeitung einfacher sowie terpenarmer (entterpenisierter) Orangenöle keine Isotopendiskriminierung auftritt, sind bei Spezialprodukten, bei denen einzelne Substanzen Konzentrationen von >70% erreichen, Abweichungen des13C/12C-Isotopenverhältnisses feststellbar.
The influence of analytical and technological procedures on the13C/12C isotope ratio of orange oil compounds
The influence of Chromatographic and technological procedures on the13C-isotope value of flavour compounds from orange oils was investigated. In order to avoid misinterpretations of isotopic data, quantitative yields during sample clean-up must be ascertained. Ordinary as well as deterpenated orange oils were not influenced by the technological processing. In the case of special products containing single compounds concentrated up to more than 70%, a shift in the13C/12C-isotope ratio was detectable.相似文献
998.
We present a method for thecompositional construction of theminimal transition system that represents the semantics of a given distributed system. Our aim is to control thestate explosion caused by the interleavings of actions of communicating parallel components byreduction steps that exploitglobal communication constraints given in terms ofinterface specifications. Theeffect of the method, which is developed forbisimulation semantics here, depends on the structure of the distributed system under consideration, and theaccuracy of the interface specifications. However, itscorrectness is independent of the correctness of the interface specifications provided by the program designer.A preliminary version appeared inProceedings of CAV'90 — Second International Workshop on Computer-Aided Verification, Vol. 531Lecture Notes in Computer Science, Springer, pp. 186–196, June 1990. 相似文献
999.
Ulrich Peuchert Yoshio Okano Yvonne Menke Steffen Reichel Akio Ikesue 《Journal of the European Ceramic Society》2009,29(2):283-291
Optical transparent polycrystalline ZrO2 ceramics were fabricated by solid-state sintering process using first vacuum sintering followed by hot isostatic pressing. In the visible wavelength range (400–800 nm), the in-line transmittance of 5.6-mm thick samples reaches 68% at exemplary wavelength 600 nm (corresponding to an in-line absorbance based on 10 of A10 = 0.08 cm?1), which is approximately 90% of theoretical limit. The refractive indices of the ZrO2 optoceramics at 630 nm (nd) are varying between 2.10 and 2.20, depending on TiO2 contents, the latter being used as sintering aid. The appearance of birefringence is strongly correlated to the addition of TiO2 as sintering additive in the ceramic samples, whereas addition of TiO2 and simultaneous increase in Y2O3 content resulted in a decrease of birefringence. 相似文献
1000.
Online BIST and BIST-based diagnosis of FPGA logic blocks 总被引:1,自引:0,他引:1
Abramovici M. Stroud C.E. Emmert J.M. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2004,12(12):1284-1294
We present the first online built-in self-test (BIST) and BIST-based diagnosis of programmable logic resources in field-programmable gate arrays (FPGAs). These techniques were implemented and used in a roving self-testing areas (STARs) approach to testing and reconfiguration of FPGAs for fault-tolerant applications. The BIST approach provides complete testing of the programmable logic blocks (PLBs) in the FPGA during normal system operation. The BIST-based diagnosis can identify any group of faulty PLBs, then applies additional diagnostic configurations to identify the faulty look-up table or flip-flop within a faulty PLB. The ability to locate defective modules inside a PLB enables a new form of fault-tolerance that reuses partially defective PLBs in their fault-free modes of operation. 相似文献