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21.
Quality of Crude Fish Oil Extracted from Herring Byproducts of Varying States of Freshness 总被引:1,自引:0,他引:1
ABSTRACT: Herring byproducts were stored at 2 and 15 °C for up to 72 h. Over time, significant increases of total volatile bases (TVB), histamine, putrescine, cadaverine, and tyramine were detected. However, only tyramine and TVB levels were temperature-dependent. The level of total polyunsaturated fatty acids (PUFAs) was constant. Longer byproducts storage gave rise to an oil with higher levels of free fatty acids, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total PUFAs, while fluorescent compounds were lower. A higher storage temperature led to oil higher in α-tocopherol and EPA levels and lower in anisidine value. Surprisingly, the oil with the highest content of PUFAs was not produced from the freshest byproducts, and oil with low oxidation products can be extracted from stored byproducts. 相似文献
22.
L. M. Du Plessis J. B. M. De Villiers W. H. Van Der Walt 《Journal of the American Oil Chemists' Society》1985,62(4):748-752
Fatty acid esters, high in linoleic acid, were prepared and stored for long-term engine tests. Storage tests with these esters were undertaken to obtain more information on optimal storage requirements and general stability characteristics. Samples were kept at three temperature levels (20 C, 30 C and fluctuating around 50 C) for a 90-day period and were removed at regular intervals for chemical and physical analysis. The influence of air, temperature, light, TBHQ and contact with mild steel was evaluated by comparing the free fatty acid, peroxide, anisidine, ultraviolet absorption, viscosity and induction periods. A statistical model was used to evaluate the data and to reduce the large number of data points to comparable curves. Storage of esters in contact with air, especially at a temperature above 30 C, resulted in significant increases in peroxide, ultraviolet absorption, free fatty acid, viscosity and anisidine values. Exclusion of air retarded oxidation at all temperature levels. A direct relationship between viscosity increases and oxidation parameters was evident. Exposure to light caused a small increase in the oxidation parameters of esters stored at the highest temperature level. Addition of TBHQ prevented oxidation of samples stored under moderate conditions. Under unfavorable storage conditions the anti-oxidant was no longer effective. Mild steel had very little effect on the oxidation parameters. Only the anisidine values of samples stored at the highest temperature level were slightly increased. Methyl esters performed slightly better than ethyl esters during the storage test. The following practical guidelines for storage of fatty acid ester fuels are: (i) airtight containers should be used; (ii) the storage temperature should be <30 C; (iii) mild steel (rust free) containers may be used, and (iv) TBHQ has a beneficial effect on oxidation stability. 相似文献
23.
Chwen-Jyh Jeng Warren B. Kindzierski Daniel W. Smith 《Canadian Metallurgical Quarterly》2007,133(3):331-339
This paper presents a particle penetration model predicting particle penetration coefficient (Pp) through a narrow crack of arbitrary incline angles (θ). The objective was to simulate Pp for outdoor-to-indoor particle penetration for residential infiltration conditions. This model assumes laminar infiltration flow and considers particle deposition from both gravitational sedimentation and Brownian diffusion. For micron-sized particles, modeling results indicate that gravitational sedimentation is the major deposition mechanism. Pp increases monotonically with ∣θ∣ because effective particle sedimentation velocity (vs?cos?θ) decreases monotonically with ∣θ∣. For submicron-sized particles (0.1?μm), Brownian diffusion is the major particle deposition mechanism. Because Brownian diffusion is a nondirectional deposition mechanism, crack inclination did not affect Pp. This study applied this model to estimate Pp for L-shaped cracks, and validated modeling results with experiments. Experimental results indicated that inertial impaction and crack entrance cutoff effects were not significant particle deposition mechanisms for the test micron-sized particles. Gravitational sedimentation was the major deposition mechanism. An L-shaped crack can be simulated as the combination of horizontal and vertical sections. This model agreed reasonably with experimental results. 相似文献
24.
Here we are presenting the case of a 70-years-old woman who has hepatic cirrhosis anti-HCV and insulin-dependent diabetes mellitus, without relevant epidemiologic ascendants or previous transfusions and HBV, HIV negatives. On admission to our hospital she showed signs of autoimmune hemolytic anaemia (AHA) which was confirmed by positive direct Coombs test and an improvement in blood test after corticoid treatment. Having discarded other possible causes such as drugs infectious diseases or essential mixed cryoglobulinemia (CME), we put forward the possible association between AHA and infection by HCV, where AHA was an extrahepatic immunological manifestation of HCV. This fact has never been brought to light in previous medical literature. 相似文献
25.
MF Chen YY Jan CS Wang TL Hwang LB Jeng SC Chen TC Chao 《Canadian Metallurgical Quarterly》1997,84(9):1229-1232
The effect of phenylephrine-induced reflex parasympathetic stimulation on QT interval and its dispersion was studied in 16 healthy subjects with a history of paroxysmal supraventricular tachycardia, both during sinus rhythm and during atrial pacing. Results demonstrate that rapid reflex parasympathetic stimulation does not influence QT interval duration or QT dispersion, and also emphasize the inappropriateness of Bazett's formula, the need for comparison of QT intervals during identical heart rates, and the importance of analyzing all 12 leads of a standard electrocardiogram when assessing the effects of various interventions on the QT interval. 相似文献
26.
M Fernández Arjona J Mu?oz-Delgado Salmerón S Shihadei PJ Colomar JA García Estevez 《Canadian Metallurgical Quarterly》1997,21(1):64-66
The application of frozen and radiation sterilized allogenic bone grafts for reconstructions in orthopaedic operations is described. Analysis of results of treatment of 1125 patients was performed. It was found that use of preserved bone allows to reduce the extend and duration of surgery. Nearly total substitution of grafts may be seen in 3 to 8 months after surgery. 相似文献
27.
Subspace-based signal analysis using singular value decomposition 总被引:10,自引:0,他引:10
Van Der Veen A.-J. Deprettere E.F. Swindlehurst A.L. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1993,81(9):1277-1308
A unified approach is presented to the related problems of recovering signal parameters from noisy observations and identifying linear system model parameters from observed input/output signals, both using singular value decomposition (SVD) techniques. Both known and new SVD-based identification methods are classified in a subspace-oriented scheme. The SVD of a matrix constructed from the observed signal data provides the key step in a robust discrimination between desired signals and disturbing signals in terms of signal and noise subspaces. The methods that are presented are distinguished by the way in which the subspaces are determined and how the signal or system model parameters are extracted from these subspaces. Typical examples, such as the direction-of-arrival problem and system identification from input/output measurements, are elaborated upon, and some extensions to time-varying systems are given 相似文献
28.
聚六亚甲基碳酸酯二醇增韧环氧树脂的结构与性能 总被引:6,自引:0,他引:6
采用羟基封端的脂肪族碳酸酯-聚六亚甲基碳酸酯二醇对环氧树脂进行了增韧,通过扫描隧道显微镜,扫描电子显微镜,差示扫描量热分析以及动态力学性能分析等方法研究了增韧EP的结构与性能的关系。 相似文献
29.
Shih-Jen Wang Shih-Hsiin Chang Chun-Sheng Chien Suh-Chyn Jeng 《Nuclear Engineering and Design》1997,167(3):335-343
The purpose of this paper is to simulate the pressure set-point change transient with the Kuosheng plant analyzer. The Kuosheng plant analyzer was developed for the Kuosheng nuclear power station based on the boiling water reactor plant analyzer of the Brookhaven National Laboratory and the Chinshan plant analyzer of the Taiwan Power Co. First, the pressure control system (PCS) model was verified on a stand-alone basis, with the sensed dome pressure test signal as the input variable. Then, a transient induced by a step change in the pressure set-point was simulated with the Kuosheng plant analyzer and compared with the test data. The predicted results of the main system variables showed good agreement with the test data-within 8% of the maximum relative deviation. In addition, the PCS performance of the Kuosheng nuclear power station was analyzed. 相似文献
30.
Ming-Jer Jeng Jenn-Gwo Hwu 《Electron Device Letters, IEEE》1996,17(12):575-577
Anodic oxidation at room temperature with pure deionized water as electrolyte and then followed by high-temperature rapid thermal densification was used to prepare high breakdown endurance thin-gate oxides with thicknesses of about 50 Å. It was observed that the oxides prepared by anodic oxidation followed by rapid thermal densification (AOD) show better electrical characteristics than those grown by rapid thermal oxidation (RTO) only. The AOD oxides have a very low midgap interface trap density, Ditm, of smaller than 1×1010 eV-1 cm-2 and negative effective oxide trapped charge. From the smaller leakage currents observed during staircase ramp voltage time-zero dielectric breakdown (TZDB) and constant field time-dependent dielectric breakdown (TDDB) testings, it is supposed that the uniform interfacial property and the pretrapped negative charges in AOD oxides are responsible for the improved characteristics 相似文献