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Catalysts of quaternary composition have been prepared and tested for the Sabatier process. For catalyst syntheses the following techniques have been used: sol‐gel methods, wet impregnation and incipient wetness impregnation. The Sabatier reaction was carried out at temperatures between 520 K and 670 K, pressures of 15 bar and 30 bar using a mixture H2:CO2 of 4:1. Activity screening of the microscale wall catalysts was performed by a custom‐built 10‐fold parallel gas‐flow microreactor setup in sequential operating mode. To analyze the gas phase compositions GC‐FID was used. 相似文献
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The curing of wood adhesives has so far been evaluated on a basis of parameters, which offer process optimization only to a small degree. However, the curing becomes analyzable in detail by using oscillation measurements and a test setup adapted to the bonding process. With time sweep measurements, the adhesion process can be divided into characteristic ranges of molecular and structural processes. This method is presented and analyzed using a polyurethane prepolymer for joining wood-based materials. 相似文献
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Siegrid De Baere Thomas De Mil Gunther Antonissen Mathias Devreese Siska Croubels 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(9):1728-1738
Mycotoxin binders are feed additives which are mixed in the feed to adsorb mycotoxins and thereby reducing their toxic effects on animals. Interactions with orally administered veterinary medicinal products, such as antimicrobials or coccidiostats, have been reported previously. This paper describes an in vitro model to screen the interaction between mycotoxin binders and veterinary drugs with respect to the non-specific binding of drugs. It is designed as a static setup using a single concentration of drug and binder in a feed-containing or a feed-plus-mycotoxin-containing matrix, buffered at different pH values. The model was applied to two frequently used antimicrobials in veterinary medicine, doxycycline (DOX) and tylosin (TYL), one major mycotoxin, aflatoxin B1 (AFB1), and four mycotoxin binders. Proportions of feed, DOX or TYL, AFB1, and binder are equivalent to the in vivo situation for broiler chickens, while pH and volume of the buffer are representative of the gastrointestinal tract of chickens. A substantial binding of DOX (~ 88%) and TYL (~ 66%) to the feed-matrix was observed. For the mycotoxin binders, similar results were obtained for DOX and TYL; more specifically up to an inclusion rate of 20 g binder/kg feed, no significant binding was demonstrated, determined as the free concentration of DOX and TYL. A single exception was noticed for TYL and one specific bentonite-based mycotoxin binder, for which no significant interaction could be demonstrated up to 10 g binder/kg but there was an effect at 20 g/kg. In all cases, there was no competition between the tested drugs DOX or TYL and the mycotoxin AFB1 for binding to the bentonite-based mycotoxin binder. 相似文献
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Thixoforging allows one-step forming processes of near-net shape components having excellent mechanical properties. However, the high sensitivity of thixoforging regarding process conditions requires precise modelling and determination of process related parameters. At the same time, simple numerical design proves challenging because of the inaccuracy of existing one-phase material models regarding the shear thinning flow behaviour of semi solid metals. Consequently, this paper deals with the development of a new one-phase material model providing a more precise simulation of materials’ shear rate dependency. By using this model, simulations could be performed, which allowed the prediction of solidification and flow-related component defects. 相似文献
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The hot corrosion Type II of the alloys FeCr20, FeCr20Ni10, FeCr20Ni20, and FeCr20Co10 is investigated at 700°C in air + 0.5% SO2 with deposits consisting of Na2SO4 and a eutectic mixture of Na2SO4 and MgSO4 for 24, 100, and 300 h. The alloying elements nickel and cobalt have a positive influence when tests are conducted using a MgSO4‐Na2SO4 deposit. In this case, they reduce the metal loss and increase the time to the propagation stage. In contrast, when the alloys are exposed with a Na2SO4 deposit, these alloying elements increase the metal loss and allow for the transition to the propagation stage because they can form molten phases with the Na2SO4. During the incubation stage an oxide scale forms on the FeCr20 alloy, which is thicker than the one formed during exposure without a deposit, and iron oxides are observed, which precipitate in the deposit. The propagation stage occurs by a dissolution and precipitation mechanism forming localized pitting attack. Iron is the main species that dissolves and precipitates, while chromium remains mainly as an oxide beneath the initial surface. The additional elements are found in the pit and in the salt deposit. 相似文献
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