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排序方式: 共有362条查询结果,搜索用时 15 毫秒
41.
Mohammad Amer Arafah Hazza S. Al‐Harbi Saad Haj Bakry 《International Journal of Network Management》2007,17(4):295-305
Grid computing is emerging as the foundation upon which virtual organizations can be built. Such organizations are becoming of increasing importance for tackling various projects, both in academic and in business fields. This paper is concerned with presenting an integrated view of the grid to readers interested in understanding it, or perhaps in developing it further or making use of it in the future. The target view is based on the STOPE (strategy/technology/organization/people/environment) framework that has previously been used to integrate the issues of various information technology problems over its well‐defined domains. For strategy, the view considers the reasons associated with the need for the grid, including grid services and grid benefits. For technology, the technical components of the grid and their functions are taken into account. For organization, the organizations concerned with the development, technology production, service provisioning and use of the grid are considered. For people, those associated with the grid in the related organizations are taken into account. For the environment, rules, practices and support associated with the grid are discussed. Finally, the paper emphasizes questions that need to be answered in order to contribute to the future development of the grid. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
42.
Abdel-Sattar I. Abu-Shady Samir A. Amer Mohamed F. Hegazi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,52(2):177-185
Salting out of acetic acid from aqueous solutions containing various concentrations of sodium chloride into some organic solvents has been studied at various temperatures. The solvents include cyclohexane, carbon tetrachloride, 1,2-dichloroethane, isopropyl ether, 2-pentanone and 1-heptanol. The results are consistent with a transfer mechanism involving monomer partitioning, dimerization and dimer return to the aqueous phase. Factors favoring monomer partitioning such as rise in both temperature and salt level retard dimer return, a process which is found to be significant in dimerization-enhancing solvents. The sensitivity of various solvents towards salt effect increases in the order 1-heptanol < isopropylether < 1,2-dichloroethane < 2-pentanone < cyclohexane < carbon tetrachloride which generally parallels in the reverse order the extent of stabilization of the acid by various solvent interactions. 相似文献
43.
The heavy crude oil exhibits a non-Newtonian shear thinning behavior over the examined shear rate. The viscosity of the heavy crude oil decreases about 15.6% when the temperature increased from 30 to 60°C. Heavy crude oil was blended with the aqueous solution of surfactant and saline water in different volumetric proportions of NaCl, and Na2CO3 solution mixtures. The addition of 50% of the mixture to the heavy crude oil causes a strong reduction in the viscosity, about 67.5% at 60°C. The heavy crude oil fits the Power law model since it has the lowest average absolute percent error of 0.0291. The flow behavior index of the heavy crude oil reaches a value of 0.9305 at a temperature of 30°C and it increases to 0.9373 when the temperature raises 60°C, while the consistence coefficient decreases from 2.8811 to 2.3558. 相似文献
44.
Zeolitic materials with hierarchical porous structures 总被引:2,自引:0,他引:2
Lopez-Orozco S Inayat A Schwab A Selvam T Schwieger W 《Advanced materials (Deerfield Beach, Fla.)》2011,23(22-23):2602-2615
During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post-synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open-cellular ceramic foams as (non-reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented. 相似文献
45.
Monthly average daily measurements over a three-year period (1985–1987) for eight weather parameters are reported. The computed three-year averages of total yearly global radiation, diffuse radiation, hemispherical global infrared radiation, and global UV radiation were 1,939.08, 696.82, 3,144.30, and 87.78 kWh/m2, respectively. Further, employing least-squares linear regression analysis, empirical fits expressing the monthly average daily measurements as a function of month of the year were developed for seven weather parameters. 相似文献
46.
H. A. Amer M. F. Sedik F. A. Khalafalla Hoda Abd El-Ghany Awad 《Molecular nutrition & food research》1991,35(2):133-138
The main muscle constituents in 100 male and female prawn as related to their moisture contents were analysed. The study was aimed to assess the nutritional state in which prawn exists and determine which sex is the more susceptible to changes. Significant higher levels of ash and water in males and relatively greater contents of fat, protein, carbohydrates, phosphorus and gross energy in females were determined. The data given in this study can establish the non starved condition in which the prawn exist. The variation in muscle constituents between male and female prawn reflects the differences in the sex development and their energy requirements during maturation. 相似文献
47.
We present a new model for testing real-time protocols with multiple timers, which captures complex timing dependencies by using simple linear expressions involving timer-related variables. This new modeling technique, combined with the algorithms to eliminate inconsistencies, allows generation of feasible test sequences without compromising their fault coverage. The model is specifically designed for testing to avoid performing full reachability analysis, and to control the growth of the number of test scenarios. Based on extended finite state machines, it is applicable to languages such as SDL, VHDL, and Estelle. The technique models a realistic testing framework in which each I/O exchange takes a certain time to realize and timers can be arbitrarily started or stopped. A software tool implementing this technique is used to generate test cases for the US Army wireless standard MIL-STD 188-220. 相似文献
48.
A. A. Fadda H. A. Etman F. A. Amer M. Barghout Kh. S. Mohamed 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,62(2):165-169
Ten variously substituted derivatives ( IIa–j ) of 3′-(benzimidazol-2-yl)-4′-hydroxyazobenzene were prepared. The effects of the nature and orientation of the substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres were evaluated. 相似文献
49.
MashhourMustafaBaniAmer 《电子科学学刊(英文版)》2003,20(1):20-28
This papenr deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events.The main purpose of this paper is to present a procedure for analysis of the effects of internal noise generated by the active circuits and to evaluate the output noise of the author‘s new designed bioelectric amplifier that caused by internal effects to the amplifier circuit itself in order to compare it with the noise generated by conventional amplifiers.The obtained analysis results of internally generated noise showed that the total output noise of bioelectric active circuits does not increase when some of their resitors have a larger value.This behavior is caused by the different transfer functions for the signal and the respective noise sources associated with these resistors.Moreover,the new designed bioelectric amplifier haws an output noise less than that for conventional amplifiers.The obtained analysis results were also experimentally verified and the final conclusions were drawn. 相似文献
50.
Pyrimidine‐5‐carboxylate derivative Ia was utilised as a key intermediate for the synthesis of new pyrimidine derivatives. Thiopyrimidine derivative Ia undergo N‐methylation using methyl iodide afforded III. Methylsulfanyl moiety in II was easily removed when reacted with phenyl hydrazine and thiosemicarbazide afforded pyrimidine derivatives IV and VI, respectively. The reaction on nitrogen atom in Ia using 1,3‐dibromo‐propane, benzoyl chloride, phosphorous oxychloride afforded VIII, IX and X, respectively. The reaction using 1,3‐dibromo‐propane or 1,2‐dibromo‐ethane furnished the formation of the corresponding fused cycles containing sulfur. Representative compounds of the synthesised products were evaluated as antioxidant and corrosion inhibitors for gasoline lube oils. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献