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Katharina Strohmeier Sigurd Schober Martin Mittelbach 《Journal of the American Oil Chemists' Society》2014,91(7):1217-1224
An easy and efficient method for the separation of saturated and unsaturated fatty acid mono alkyl esters, prepared from animal fat, was developed. The most efficient separation was achieved by the use of solvents such as methanol and acetone at low temperatures. The dilution of the alkyl esters with 10 times the amount of solvent (10:1 v/w) and storage of the mixture for 4 h at ?22 °C could be defined as optimum conditions. After filtration of the saturated fraction at the corresponding temperature very pure fractions were obtained. For fatty acid methyl esters deriving from tallow, with an initial content of saturated fatty acids of almost 50 %, a saturated ester fraction with only 5 % unsaturated fatty acids and an unsaturated ester fraction with about 9 % of saturated fatty acids could be obtained. The solvent easily could be recovered by distillation. In addition fatty acid ethyl, 1‐propyl, 2‐propyl, 1‐butyl, tert‐butyl and 3‐methyl‐1‐butyl esters were prepared and separated into saturated and unsaturated fractions. All fractions were analyzed according to the fatty acid compositions and showed similar or slightly worse results compared to the methyl esters. The cold filter plugging points of the unsaturated fractions were measured, showing the lowest value for the unsaturated methyl ester fraction at ?26 °C. The fractionation with the use of solvents is an easy tool in order to obtain fatty acid alkyl esters with excellent cold temperature behavior out of animal fat. 相似文献
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Pio John S. Buenconsejo Robert Zarnetta Dennis König Alan Savan Sigurd Thienhaus Alfred Ludwig 《Advanced functional materials》2011,21(1):113-118
The Ti–Ni–W two‐phase shape memory alloy (SMA) thin film system is presented as a prototype for new SMAs with tailorable thermal transformation hysteresis (ΔT). The concept is to combine the SMA TiNi with almost insoluble W to create the two‐phase system (TiNi)–(β‐W). This system behaves like a pseudobinary TiNi system. Phase transformation behavior for compositions above the solubility limit of W in TiNi exhibit a B2–R phase transformation with characteristically small ΔT. Moreover, ΔT is dependent on the amount of W and it can be tailored to zero and even negative. This phenomenon is rationalized as being due to the mechanical interaction between the phases B2‐TiNi and β‐W. The presented results are very promising for the development of high‐speed Ti–Ni‐based SMA actuators. 相似文献
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Back Cover: [3H]UR‐DE257: Development of a Tritium‐Labeled Squaramide‐Type Selective Histamine H2 Receptor Antagonist (ChemMedChem 1/2015) 下载免费PDF全文
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Sigurd Hveem 《Building Research & Information》2013,41(1):56-59
Civil Engineer Sigurd Hveem at the Norwegian Building Research Institute, BI, describes the laboratory and field tests carried out on the dynamic response of different lightweight timber floors to establish new design guidelines. NBI are also looking at theoretical calculation methods in order to predict the results obtained by measuring dynamic properties. 相似文献
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In order to develop future manufacturing strategies the chemical and pharmaceutical industry works on the implementation of process intensification and new modularization methods. In this paper current challenges, process intensification approaches and future manufacturing initiatives are summarized and discussed. 相似文献
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This study prospectively investigated the effects of psychological hardiness, job control, and job demands on medically certified sickness absence. Data from a questionnaire survey were combined with archival data for sickness absence among 7,239 civilian and military employees of the Norwegian Armed Forces (84.3% male, 69.8% military). A 2-component hurdle regression was used in the statistical analyses of the sickness absence data. After controlling for age, sex, and baseline absence, hardiness predicted both the likelihood of having any sickness absence (odds ratio = 0.97) and the number of absence spells (a 6.5% decrease in the expected count for 1 standard deviation change in hardiness). In addition, an interaction was found among hardiness, job control, and psychological demands. When demands were high, high job control was associated with more absence among employees with low levels of hardiness. Together, these findings point to hardiness as an important individual resource in relation to health, and that it is necessary to consider individual differences when examining the effects of work characteristics. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
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An industrial and academic perspective on plantwide control 总被引:1,自引:0,他引:1
The purpose of this paper is to stress the importance of selecting the right plantwide control structure and the need for a formalized approach that can encompass the many issues that arise in plantwide control design. Since the concept of process control design based on a holistic view of the process came about, the variety of procedures and approaches to the design problem has illustrated the difficulty of a unified approach. Using examples, the need and advantages of using a systematic approach based on considering the plant economics are highlighted. The examples deal with disturbance rejection, throughput maximization and economic optimization of plants consisting of parallel units. 相似文献