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41.
Optimization of Multireservoir Systems by Genetic Algorithm 总被引:1,自引:1,他引:0
Application of optimization techniques for determining the optimal operating policy of reservoirs is a major issue in water
resources planning and management. As an optimization Genetic Algorithm, ruled by evolution techniques, have become popular
in diversified fields of science. The main aim of this study is to explore the efficiency and effectiveness of genetic algorithm
in optimization of multi-reservoirs. A computer code has been constructed for this purpose and verified by means of a reference
problem with a known global optimum. Three reservoirs in the Colorado River Storage Project were optimized for maximization
of energy production. Besides, a real-time approach utilizing a blend of online and a posteriori data was proposed. The results
obtained were compared to the real operational data and genetic algorithm was found to be effective and can be utilized as
an alternative technique to other traditional optimization techniques. 相似文献
42.
Environmental concerns and limited resource of petroleum fuels have caused interests in the development of alternative fuels for internal combustion (IC) engines. For diesel engines, alcohols are receiving increasing attention because they are oxygenated and renewable fuels. Therefore, in this study, the effect of injection timing on the exhaust emissions of a single cylinder, naturally aspirated, four-stroke, direct injection diesel engine has been experimentally investigated by using methanol-blended diesel fuel from 0% to 15% with an increment of 5%. The tests were conducted for three different injection timings (15°, 20° and 25 °CA BTDC) at four different engine loads (5 Nm, 10 Nm, 15 Nm, 20 Nm) at 2200 rpm. The experimental test results showed that Bsfc, NOx and CO2 emissions increased as BTE, smoke opacity, CO and UHC emissions decreased with increasing amount of methanol in the fuel mixture. When compared the results to those of original injection timing, NOx and CO2 emissions decreased, smoke opacity, UHC and CO emissions increased for the retarded injection timing (15 °CA BTDC). On the other hand, with the advanced injection timing (25 °CA BTDC), decreasing smoke opacity, UHC and CO emissions diminished, and NOx and CO2 emissions boosted at all test conditions. In terms of Bsfc and BTE, retarded and advanced injection timings gave negative results for all fuel blends in all engine loads. 相似文献
43.
Sheet metal hydroforming is a deep drawing process that uses a pressure medium for load transmission. The process is mainly influenced by the control of the blank holder force and the fluid pressure. This report describes investigations of a newly developed process-control system. Process variables can be controlled by the sealing state of the tool. The detection is performed by a CCD-camera system that allows the continuous recording of occurring leakages. Different control strategies can be used to control the multiple process parameters. This paper describes the performance and the limits of the aforementioned technology. 相似文献
44.
In this paper, the compensation advantage of the first-generation current conveyor (CCI) over the second-generation current
conveyor (CCII) in tunable circuits is shown. For this purpose, a new floating frequency dependent negative resistor (FDNR)
simulator using three CCIs is presented and employed in a third-order high-pass filter. The compensation feature of the CCI
is shown for the proposed high-pass filter. As a second example, the presented compensation method is tested in a second-order
band-pass filter constructed with two CCIs. Applying the proposed compensation technique, the CCI-based circuits can operate
in lower biasing currents, which result in lower power consumption. 相似文献
45.
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47.
Material selection, one of the mostly encountered decision problems in material science literature, is still an onerous task for manufacturing organisations. Achieving accurate solution to this issue, the paper developed a model selection interface to enable analytical solutions to different problem concepts in material selection under multiple attribute decision-making (MADM) environments. Specifically, the generic framework of the fuzzy axiomatic design-model selection interface (FAD-MSI) is modified and successfully applied to the different material selection problem concepts. Consequently, the derived problem-model sets can be referred to accomplish further proposals on this era. 相似文献
48.
Mustafa Öztaş Metin Bedir Şule Ocak R. Güler Yıldırım 《Journal of Materials Science: Materials in Electronics》2007,18(5):505-512
ZnS thin films were prepared by spray pyrolysis technique using aqueous of zinc chloride and thiourea at molar ratio of 1:1,
1:2, and 2:1. The depositions were carried out on substrates heated from 400 to 520 °C The films were then annealed under
sulphur atmosphere for 90 min at 450 and 550 °C. The crystallites exhibit preferential orientation along the [002]α or [111]β directions. The films were characterized by XRD and SEM. The structure and morphology of sprayed films are controlled by
both, the substrate temperature and the precursors molar ratio in the solution. The values of optical bandgap have been determined
from the absorption spectra. 相似文献
49.
Metin Ergeneman Turgut
zakta Filiz Karaosmano lu H. Ertu rul Arslan 《Petroleum Science and Technology》1997,15(7):667-683
Vegetable oils have chances to be used in Diesel engines as alternative fuels contributing to the solution of some agricultural, environmental and economical problems. Direct use of them has some technical problem yet but as blended fuels with diesel fuel or esters they have places on the application area. In this paper the effect of the compression ratio on ignition delay is investigated in an ASTM-CER engine working with four different types of vegetable oil of Turkish origin (sunflower, corn, soybean, and olive oil) blended with grade No.2-D diesel fuel at a ratio of 20/80 (v/v) and the results are compared with baseline diesel fuel. Longer ignition delay periods have generally been obtained for blend fuels ranking from olive oil to sunflower oil as compared to diesel fuel. 相似文献
50.
A Multi-Level Approach to Measuring the Benefits of an Erp System in Manufacturing Firms 总被引:1,自引:0,他引:1
This research study examines associations between the business characteristics of manufacturing firms and their perceived benefits from ERP system investments. the perceived ERP benefits are measured at two levels: (1) an enterprise level and (2) a specific IT module level. the perceived value for ERP investments was consistently better explained at the specific IT module level. 相似文献