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Salah Selmi Zouhour LimamIrineu Batista Narcisa M. BandarraMaria L. Nunes 《International Journal of Refrigeration》2011,34(5):1315-1322
Sardine oil released during sardine mince preparation showed good quality with a low hydroperoxide content, excellent color and high content (19.23%) of eicosapentaenoic acid. Recovered sardine oil was stored at two different temperatures (+4 °C and +35 °C) for 28 days with or without the addition of α-tocopherol (50 and 100 ppm). Peroxide values and thiobarbituric acid reactive substances of control sardine oil significantly increased to reach 29.9 meq O2/kg oil and 46.48 mg MA/kg during storage at +35 °C, but the increase was considerably less (4.36 meq O2/kg oil and 13.21 mg MA/kg oil respectively) in oil stored at +4 °C. A slight increase (1.5%) in the free fatty acid content was recorded in oil stored at 35 °C. A significant decrease of polyunsaturated fatty acids was recorded after storage, particularly in oil stored at 35 °C, while higher percentages of saturated and monounsaturated fatty acids were observed. Storage at +4 °C combined with addition of α-tocopherol (100 ppm) had a beneficial effect on sardine oil stability. 相似文献
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Jaouadi Zouhour Abbas Tajammal Morgenthal Guido Lahmer Tom 《Structural and Multidisciplinary Optimization》2020,61(4):1495-1514
Structural and Multidisciplinary Optimization - Civil engineers focus on developing an optimum design that is cost-effective without compromising the performance. Experiences from optimizing... 相似文献
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Ibtissem Hamrouni Sellami Iness Bettaieb Rebey Jazia Sriti Fatma Zohra Rahali Ferid Limam Brahim Marzouk 《Food and Bioprocess Technology》2012,5(8):2978-2989
Chemical composition and antioxidant activity of Salvia officinalis essential oil (EO) were studied under different drying methods of plant material. Results obtained showed that dried plant material yielded more essential oils than did the fresh one. The highest EO yields were obtained by infrared drying at 45?°C (0.39%) followed by air drying (0.30%) and oven drying at 45?°C (0.26%). The analysis of EOs by gas chromatography?Cmass spectrometry, showed in each of 55 identified compounds belonging mostly to oxygenated monoterpenes. This class of compounds was significantly affected by following drying methods: oven at 65?°C, microwave (500?W), and infrared at 45?°C. The main components of sage EO, 1,8-cineole, ?? and ??-thujone, camphor, viridiflorol, and manool showed significant variation (p?<?0.05) with drying methods. Their concentrations increased significantly, particularly when drying sage at ambient air. Finally, the screening of antioxidant activity of the different sage EOs using the di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radical (DPPH) assay showed an appreciable reduction of the stable radical DPPH, although microwave drying was the most efficient method with an IC50 of 1.60% as compared with fresh plant (IC50?=?5.32). 相似文献
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In this article, different procedures of constructing control charts for linguistic data, based on fuzzy and probability theory, are discussed. Three sets of membership functions, with different degrees of fuzziness, are proposed for fuzzy approaches. A comparison between fuzzy and probability approaches, based on the Average Run Length and samples under control, is conducted for real data. Contrary to the conclusions of Raz and Wang (1990b) the choice of degree of fuzziness affected the sensitivity of control charts. 相似文献
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F Limam K Chahed N Ouelhazi R Ghrir L Ouelhazi 《Canadian Metallurgical Quarterly》1998,49(5):1219-1225
Peroxidase (POD) activity was investigated in Catharanthus roseus cell suspensions cultured under different hormonal conditions. Depletion of 2,4-dichlorophenoxyacetic acid (2,4-D) from the culture medium enhanced POD activity in cells and spent medium. Addition of phytohormones, in particular the auxin 2,4-D, reduced POD activity in medium and cellular compartments and enhanced ionically cell-wall bound POD. The differential modulation of POD is due to hormone effects on synthesis and/or accumulation of POD, rather than on the secretion process. Qualitative analysis showed that 2,4-D, but not cytokinins, regulated the synthesis of a basic isoform. The cytokinin treatment seemed to affect acidic rather than basic isoforms. The presence of basic POD is correlated with the capacity of cells to produce indole alkaloids. The major extracellular basic isoperoxidase was purified to homogeneity from culture medium of Catharanthus roseus cell suspensions. The isolated peroxidase is a haem protein with a M(r) of 33,000 and a pI close to 9. The effect of pH on peroxidase activity was studied using guaiacol as substrate and the optimum pH determined at 25 degrees was 6.0. This enzyme acted on guaiacol, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), o-dianisidine, o-phenylenediamine (o-PD) and pyrogallol, but had no effect on syringaldazine or coniferyl alcohol substrates. 相似文献
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The research presents an improved method of rational design of energy-efficient low-rise residential buildings according to their life cycle. The mathematical model for finding the optimal version of draft power-efficient residential building has been developed. For conditions of Ukraine the optimization problem has been set and solved (finding the optimal version of the draft energy-efficient buildings). The calculations prove the fact that the construction of passive houses in Ukraine today is economically feasible. Scientific and practical regulations, outlined in the research, can be used by all participants of the investment programs, and energy-efficiency projects, renovation projects and developing normative-technical documents. 相似文献
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Experimental and numerical investigation of static and dynamic axial crushing of circular aluminum tubes 总被引:8,自引:3,他引:5
A comprehensive experimental and numerical study of the crash behavior of circular aluminum tubes undergoing axial compressive loading is performed. Non-linear finite element analyses are carried out to simulate quasi-static and dynamic test conditions. The numerical predicted crushing force and fold formation are found to be in good agreement with the experimental results. A summary of available analytical solutions is presented in order to estimate the mean crushing load and establish a comparison between these analytical loads and the experimental one. Some observations are made on the influence of geometrical imperfections and material strain rate effect. 相似文献
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The effect of localized axisymmetric initial imperfections on the critical load of elastic cylindrical shells subjected to axial compression is studied through analytical modeling. Some classical results regarding sensitivity of shell buckling strength with respect to distributed defects having axisymmetric or asymmetric forms are recalled. Special emphasis is placed after that on the more severe case of localized defects satisfying axial symmetry by displaying an analytical solution to the Von Kármán–Donnell shell equations under specific boundary conditions. The obtained results show that the critical load varies very much with the geometrical parameters of the localized defect. These variations are not monotonic in general. They indicate, however, a clear reduction of the shell critical load for some defects recognized as the most hazardous isolated ones. Reduction of the critical load is found to reach a level which is up to two times lower than that predicted by general distributed defects. 相似文献