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91.
An expert system for dynamic security assessment (DSA) is described in which artificial intelligence techniques are applied to the transient energy function (TEF) method. The effect of contingencies on the security level and its rate of change with changing system conditions and parameters are computed using the results of the TEF sensitivity analysis program. The expert system determines the loading trend and analyzes the data obtained from TEF to compute the trend of the security index. The trend of the control parameters can then be adjusted to maintain the security index within a range of safe values. An example is given using data collected from the Northern States Power Company (NSP) where the expert system correctly computed the security index and suggested adjustments to system parameters 相似文献
92.
Hesham A. Eissa Gamal M. Fouad & Abd Elhafeeze A. Shouk 《International Journal of Food Science & Technology》2008,43(6):1088-1098
The effect of different thermal and chemical pretreatments on quality and enzyme activities of smoked mushroom was investigated. Mushrooms were blanched (water and steam) and dipped in different concentrations of sulphites (SO2), hydrogen peroxide (H2O2), ethylene‐di‐amine tetra‐acetic acid (EDTA) and citric acid for 10 min before smoking. Enzyme activities, colour characteristics, microbiological and sensory examinations were carried out every 2 weeks up to 8 weeks of storage in refrigerator at 4 °C. Results could be concluded that smoked mushroom pretreated with SO2, H2O2 and steam blanching had the best colour values, the better score for all sensory characteristics and lower non‐enzymatic browning compared with other pretreatments. The most effective pretreatment against total aerobic bacteria and yeast & moulds were citric acid, EDTA and steam, and then smoking of mushroom can be attributed to the reduction of microbial counts. The most effective pretreatments on quality and safety of smoked mushrooms were H2O2 and steam. It can be concluded that thermal and chemical treatments, rather than smoking of mushroom, reduce enzyme activities and are suitable to preserve mushrooms. 相似文献
93.
S. A. Abd El‐Maksoud 《工业材料与腐蚀》2003,54(2):106-112
The effect of some synthesized pyrazolo containing compounds on the corrosion of carbon steel in 1 M H2SO4 was investigated. The investigation involved electrochemical polarization methods (potentiodynamic, Tafel extrapolation and the determination of the polarization resistance). A significant decrease in the corrosion rate of carbon steel was observed in the presence of the investigated compounds. The results show that these compounds act as mixed type inhibitors, but the cathode is more preferentially polarized. The relative inhibition efficiency of these compounds depends on both the nature and concentrations of the investigated compounds. Compounds are found to adsorb on the carbon steel surface according to the Langmuir adsorption isotherm. 相似文献
94.
Fouad EA El-Badry M Mahrous GM Alanazi FK Neau SH Alsarra IA 《Drug development and industrial pharmacy》2011,37(12):1463-1472
The present research investigates the enhancement of the dissolution rate of celecoxib by using spray-drying to prepare a solid dispersion with various polymers, namely Kollicoat IR? (Kollicoat), polyvinyl alcohol (PVA) 22000, or polyethylene glycol 6000 (PEG). The investigated drug-to-polymer mass ratios were 1:1, 1:2, and 1:4 by weight. Hydroalcoholic or methylene chloride solvent systems were used. The obtained yields ranged from 65% to 78%, whereas the entrapment efficiencies were between 68% and 82%. The results revealed an increase in the dissolution rate of the prepared particles up to 200% within 20 min. The prepared particles were investigated using differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The increased dissolution rate was attributed to hydrogen bond formation between celecoxib and each polymer together with the reduced size of the formed particles offering a greater overall surface area. It was concluded that spray-drying may be considered a successful one-step technique to improve the dissolution rate of celecoxib when using Kollicoat, PVA, or PEG as the carrier polymer. 相似文献
95.
96.
A necessary and sufficient condition to test the robustness of a regulator of uncertain linear systems with constrained control is given. The candidate regulator for this test is that stabilizing nominal systems. An illustrative example is also given. 相似文献
97.
Development of phase morphology in immiscible poly(styrene‐co‐acrylonitrile)/poly(butylene terephthalate) nanoblends: Mechanical properties and effect of the compatibilizer 下载免费PDF全文
Lidiane Cristina Costa José Donato Ambrósio Marcelo Aparecido Chinelatto Elias Hage Junior 《应用聚合物科学杂志》2017,134(27)
Nanoblends were obtained from poly(styrene‐co‐acrylonitrile) (SAN) as a matrix, and poly(butylene terephthalate) (PBT) was used as a nanodispersed phase. Compatibilized SAN/PBT blends were prepared by reactive extrusion, and the PBT concentrations ranged between 3 and 30 wt %. Nanoblends were obtained for up to 10 wt % PBT concentrations in the presence of the compatibilizer. With 20 and 30 wt % PBT, the extruded material presented a droplet dispersed phase. The same blends were subjected to an injection‐molding process, which provided a cocontinuous phase morphology. The influence of the concentration of the dispersed phase and the type of morphology on the mechanical behavior of tensile test, flexural test, impact test, and deflection temperature of the blends was analyzed. The results show an important reduction in the particle size of the dispersed phase, which was due to the presence of the compatibilizer. Furthermore, the type of morphology and an excess of compatibilizer exerted a stronger influence on the mechanical properties than the particle size of the dispersed phase. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45030. 相似文献
98.
99.
A procedure was developed to relate the transient energy margin of a multimachine power system to the apparent impedance of a line protected by an out-of-step relay. In this procedure, only the multimachine system parameters are used, and the conventional intermediate step of forming a two-machine equivalent is eliminated. A technique for generating the swing impedance locus is described. The method is tested for a loss of generation disturbance on a 23-generator equivalent of the Florida Power & Light Co. network. The results obtained are compared with time simulation results 相似文献
100.
Studies on the potential use of nuclear desalination in Egypt have been conducted. The choice of reactor type and system concept was influenced by emphasis on relaxed technological conditions so as to fit local circumstances . Natural uranium heavy water reactors were found promising. Finer details of type of fuel, cladding, coolant, and system arrangement were left for comparative studies. The question of fuel type, fuel pin versus fuel cluster, was considered. Simplified analytical and computational techniques were adopted and results verified with published criticality measurements. It was found that the pin design would have higher breeding potentials while the cluster would provide simpler core arrangement especially if a pressure vessel design is chosen. Results are given for a typical 40 MWth project study showing core features and system characteristics. 相似文献