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41.
In the present work, the microstructural evolution and hardness of HSLA X70 joined by friction stir welding were investigated. The FSW was applied to HSLA X70 with and without the addition of titanium dioxide (TiO2) powders. To evaluate the microstructural features and hardness of different weld zones, optical microscopy and Vickers microhardness measurements were applied. The results show that the distribution of TiO2 powders is strongly dependent on the applied friction stir processing, which in turn changed significantly the microstructure and hardness profile. In this regard, the optimum stirring action resulted in a homogeneous and fine dispersion of particles leading to the domination of an acicular ferrite phase with a hardness of 370 HV. On the other hand, the lower stirring action resulted in coarse particles as well as the development of the polygonal ferrite structure with a hardness of ~185 HV. 相似文献
42.
Rudolf Sowada 《Advanced Synthesis \u0026amp; Catalysis》1981,323(2):269-278
On the Lipophilic Nature of Oxyalkyl Groups in Alkyl Ether Sulphates Effective carbon numbers and methylene group equivalent values for tetradecane sulphonates containing oxyalkyl groups as substituents as well as and for alkyl ether sulphates containing oxyalkyl groups in the chain have been calculated. These oxyethyl groups show lipophilic character, at least up to an oxethylation degree of 10. Via ME values effective carbon numbers, critical concentrations for micelle formation and HLB-values for alkyl ether sulphates can be calculated. HLB group numbers depending on oxalkylation degree are tabulated; the known value of + 0,33 for OCH2CH2 is valid only for nonionic surfactants. 相似文献
43.
The arc furnace technology is an ideally suited process for the treatment of hazardous and problematic waste. The operation conditions of the arc furnace can be adapted for optimal transformation of the waste material input into raw materials and usable products. The process can significantly reduce the impact of contaminated wastes and industrial residues, and enable material conversion and separation. Thus, the products of the process have various applications.
The capability of the process is illustrated with three examples, the treatment of bottom ash and filter ash from waste incineration plants, of stainless steel slags and of chromium containing residues from the refractory industry. 相似文献
44.
Piotr Długosz Angelika Rączka Adrian Kopeć Rudolf Krzyżak Paweł Darłak Marek Hebda 《Journal of Materials Engineering and Performance》2016,25(6):2261-2266
This paper presents novel opportunities for management of fly ash by synthesizing the material into cordierite ceramics and using it as a reinforcing phase for light metal alloys. Metal matrix composites (based on magnesium alloy and aluminum alloy) were produced by squeeze casting. The magnesium matrix composites with a suitably selected reinforcing phase content (2 wt.%) exhibited much better strength properties than the unmodified alloy (AM60). It was also demonstrated that the wettability (or the lack thereof) in the metal-ceramic system is critical to successful production of the composites based on the AK7 alloy with cordierite. Light alloy matrix composites reinforced with cordierite ceramics particles are innovative materials that combine high strength with low weight, which may be a key factor of merit for numerous applications of the composite in various branches of industries. 相似文献
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46.
Tania Michelle Roberts Hans-Michael Kaltenbach Fabian Rudolf 《Yeast (Chichester, England)》2020,37(5-6):336-347
Saccharomyces cerevisiae cells grown in a small volume of chemically defined media neither reach the desired cell density nor grow at a fast enough rate to scale down the volume and increase the sample number of classical biochemical assays, as the detection limit of the readout often requires a high number of cells as an input. To ameliorate this problem, we developed and optimised a new high cell density (HCD) medium for S. cerevisiae. Starting from a widely used synthetic medium composition, we systematically varied the concentrations of all components without the addition of other compounds. We used response surface methodology to develop and optimise the five components of the medium: glucose, yeast nitrogen base, amino acids, monosodium glutamate, and inositol. We monitored growth, cell number, and cell size to ensure that the optimisation was towards a greater density of cells rather than just towards an increase in biomass (i.e., larger cells). Cells grown in the final medium, HCD, exhibit growth more similar to the complex medium yeast extract peptone dextrose (YPD) than to the synthetic defined (SD) medium. Whereas the final cell density of HCD prior to the diauxic shift is increased compared with YPD and SD about threefold and tenfold, respectively. We found normal cell-cycle behaviour throughout the growth phases by monitoring DNA content and protein expression using fluorescent reporters. We also ensured that HCD media could be used with a variety of strains and that they allow selection for all common yeast auxotrophic markers. 相似文献
47.
L. Antonio González-Grajales Laura Pieper Stefan Görner Philipp Görner Rudolf Staufenbiel 《Journal of dairy science》2019,102(4):3609-3614
Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices. 相似文献
48.
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50.
Peter Werkhoff Wilfried Bretschneider Matthias Güntert Rudolf Hopp Horst Surburg 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1991,192(2):111-115
Summary The direct capillary gas Chromatographic separation oftrans--ionone andtrans--damascone enantiomers is reported using heptakis(2,3,6-tri-O-methyl)--cyclodextrin in polysiloxane as a suitable chiral stationary phase. The method described has been applied to determine the naturally occurring enantiomeric composition oftrans--ionone in the absolutes of the flowers ofBoronia megastigma Nees andOsmanthus fragrance Lour., Costus root oil (Saussurea lappa Clarke) as well as in odor concentrates of violet flowers (Viola odorata L.), fresh raspberries, carrots and vanilla pods. Furthermore, the optical purity oftrans--ionone in the solvent extracts of distilled alcoholic raspberry beverage, raspberry fruit juice concentrate and black tea was investigated.Trans--ionone was either isolated by headspace stripping in vacuo or by organic solvent extraction and subsequently enriched by multidimensional preparative Chromatographic techniques.Trans--damascone was isolated from Virginia tobacco extract and from black tea aroma and was enriched for direct chirospecific analysis by medium pressure liquid chromatography followed by multidimensional preparative capillary gas chromatography. The importance of chirality as an essential criterion for the discrimination of natural and nature-identical aromas is discussed briefly.
Chirale Analysen von Aroma-und etherischen Öl-Inhaltsstoffen Teil B. Direkte Trennung der Enantiomeren von trans--Ionon und trans--Damascon mittels Inklusionsgaschromatographie
Zusammenfassung Mit Heptakis(2,3,6-tri-O-methyl)--cyclodextrin in Polysiloxan als chiraler stationärer GC-Phase können die Enantiomeren vontrans--Ionon undtrans--Damascon direkt stereodifferenziert werden. Mit der beschriebenen Methode wird die Enantiomerenzusammensetzung vontrans--Ionon in den Absolues vonBoronia megastigma Nées undOsmanthus fragrance Lour., in Costuswurzelöl (Saussurea lappa Clarke), in den Headspace-Konzentraten von Veilchenblüten, frischen Himbeeren, Karotten und Vanilleschoten sowie in den Lösungsmittelextrakten von Himbeergeist, Himbeerfruchtsaftkonzentrat und schwarzem Tee bestimmt.Trans--Ionon wurde aus den genannten Naturprodukten mit Hilfe von multidimensionalen präparativen chromatographischen Trenntechniken angereichert und isoliert.Trans--Damascon wurde durch die Kombination MPLC/präparative Capillargaschromatographie aus Virginia Tabakextrakt und aus dem Aromastoffspektrum von schwarzem Tee erhalten und in s eine Enantiomeren aufgetrennt. Die Bedeutung der Chiralität als Beurteilungskriterium zur Unterscheidung natürlicher und naturidentischer Aromastoffe wird kurz diskutiert.相似文献