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排序方式: 共有105条查询结果,搜索用时 31 毫秒
1.
An analysis using maximum power-density criteria has been carried out for an endoreversible Carnot heat engine. The results have been compared with known results on maximum power analysis. The design parameters at maximum power density lead to smaller and more efficient endoreversible Carnot heat engines than those working at maximum power output. 相似文献
2.
Neural Computing and Applications - Among several types of fuel cells available in the market, proton exchange membrane fuel cell (PEMFC) is characterized by low operating temperature, high... 相似文献
3.
Sayyed Rasoul Mousavi Fateme Bahri Farzaneh Sadat Tabataba 《Engineering Applications of Artificial Intelligence》2012,25(3):457-467
The Shortest Common Supersequence Problem asks to obtain a shortest string that is a supersequence of every member of a given set of strings. It has applications, among others, in data compression and oligonucleotide microarray production. The problem is NP-hard, and the existing exact solutions are impractical for large instances. In this paper, a new beam search algorithm is proposed for the problem, which employs a probabilistic heuristic and uses the dominance property to further prune the search space. The proposed algorithm is compared with three recent algorithms proposed for the problem on both random and biological sequences, outperforming them all by quickly providing solutions of higher average quality in all the experimental cases. The Java source and binary files of the proposed IBS_SCS algorithm and our implementation of the DR algorithm and all the random and real datasets used in this paper are freely available upon request. 相似文献
4.
Polybutadiene/polyhedral oligomeric silsesquioxane nanohybrid: investigation of various reactants in polyesterification reaction 下载免费PDF全文
Seyed Amin Mirmohammadi Mehdi Nekoomanesh‐Haghighi Somayyeh Mohammadian Gezaz Naeimeh Bahri‐Laleh 《Polymer International》2016,65(5):516-525
Nano‐sized polyhedral oligomeric silsesquioxane (POSS) diol or ethylene glycol (EG) as diol monomer was incorporated into hydroxyl‐terminated polybutadiene (HTPBD) chain in the presence of fumaryl or thionyl chloride as extenders. Using these polyesterification reactions, two fumarate‐based polyesters and two polyester sulfites were synthesized. Each couple of polyesters and polyester sulfites includes a linear (diol:EG) and a nanohybrid macromer (diol:POSS). Full structural characterization was performed using Fourier transform infrared, 1H NMR and 13C NMR spectroscopies. Gel permeation chromatography was undertaken to study polyesterification mechanisms by deconvolution of the obtained traces. Finally, differential scanning calorimetry, thermogravimetric analysis and cell culture were performed to evaluate the structure–property relationship for the synthesized macromers in comparison with unreacted HTPBD. © 2016 Society of Chemical Industry 相似文献
5.
This study presents an energetic performance analysis for a combined power generation system consisting of a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC). In order to simulate the SOFC–ORC combined system under steady‐state conditions, a mathematical model is developed. The developed model is used to determine the potential effects caused by the changes of the design parameters on the energetic performance of the combined system. As design parameters, turbine inlet pressure, condenser temperature, fuel utilization, current density, compressor pressure ratio, and cell operating temperature are taken into account. In this regard, the electrical power and First Law efficiency are estimated by parametrical analysis and discussed comprehensively. Results of these analyses show that the efficiency is increased about 14–25% by recovering SOFC waste heat through ORC based on investigated design parameter conditions. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron, aluminum and magnesium powders was investigated for the first time. Also, the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail. The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.% and it was attributed to the possible existence of S-O bonding on copper oxides surfaces. In addition, adding magnesium nitrate salt, magnesium powder, iron nitrate salt and aluminum powder as additive associated with 0.5 wt% sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%, 0.2 wt%, 0.5 wt% and 0.5 wt%, respectively. Also, the effect of grinding time and sulfidization pH with 0.5 wt% sulfur solely was determined and pHs of 7.5 to 8.5 gave the best results. The highest recovery (75.76%) and separation efficiency (63.44%) were achieved at pH of 7.5 and 8.5, respectively. 相似文献
7.
Ahad Hanifpour Naeimeh Bahri‐Laleh Mehdi Nekoomanesh‐Haghighi Seyed Amin Mirmohammadi 《应用聚合物科学杂志》2016,133(35)
Poly1‐hexene was prepared using a conventional heterogeneous Ziegler–Natta catalyst and its stereoregularity was characterized using 13C‐NMR analysis. New kind of high impact polystyrene (HIPS) was prepared by radical polymerization of styrene in the presence of different amounts of synthesized poly1‐hexene (PH) as impact modifier (HIPS/PH) and compared with conventional high impact polystyrene with polybutadiene (HIPS/PB) as rubber phase. Scanning electron microscopy (SEM) revealed that the dispersion of poly1‐hexene in polystyrene matrix was more uniform compared with it in HIPS/PB. The impact strength of HIPS/PH was 29–79% and 80–289% higher than that in HIPS/PB and neat polystyrene, respectively. FTIR was used to confirm more durability of HIPS/PH samples toward ozonation. To study the effect of rubber type and amount on the Tgs of polystyrene, differential scanning calorimetry was employed. Results obtained from TGA demonstrated higher thermal stability of HIPS/PH sample in comparison with conventional HIPS/PB one. Our obtained results suggest new high impact polystyrene that in all studied aspects has better performance than the conventional HIPS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43882. 相似文献
8.
An ecological performance analysis for an irreversible dual-cycle cogeneration system has been performed. The objective function is called as the exergetic-performance coefficient (EPC) and defined as the ratio of total exergy output to the loss rate of availability. The general and optimal performances of the irreversible dual-cycle cogeneration system, having a finite-rate of heat transfer, heat leak and internal irreversibilities based on the EPC objective function have been investigated. Comparisons with respect to the optimal total-exergy output are also provided in order to establish the utility of the new exergetic-performance coefficient. The analyzed results of the dual-cycle cogeneration system considered, working at maximum EPC conditions, have a significant advantage in terms of entropy-generation rate and can be used for the selection of optimal design parameters. 相似文献
9.
To overcome the limitations of conventional biodiesel processing technology, researchers have investigated alternative production methods, one of these being supercritical methanol processing. It has been reported that this process can handle feed contaminants, has simple purification operations and achieves high conversion in short reaction times. Despite these promising results many factors have been shown to affect the level of conversion at the high temperatures and pressures required. The purpose of this review is to clarify the inter-relation between these parameters and evaluate the merit of supercritical methanol processing as an alternative to the conventional homogeneous alkaline catalysed method. 相似文献
10.
Bahri S Jonsson CM Jonsson CL Azzolini D Sverjensky DA Hazen RM 《Environmental science & technology》2011,45(9):3959-3966
Dihydroxyphenylalanine (DOPA) and similar molecules are of considerable interest in studies of bioadhesion to minerals, solar cells involving titanium dioxide, and biomedical imaging. However, the extent and mechanisms of DOPA adsorption on oxides in salt solutions are unknown. We report measurements of DOPA adsorption on well-characterized rutile (α-TiO?) particles over a range of pH, ionic strength, and surface coverage as well as a surface complexation model analysis establishing the stoichiometry, model surface speciation, and thermodynamic equilibrium constants, which permits predictions in more complex systems. DOPA forms two surface species on rutile, the proportions of which vary strongly with pH but weakly with ionic strength and surface loading. At pH < 4.5 a species involving four attachment points ("lying down") is important, whereas at pH > 4.5 a species involving only two attachment points via the phenolic oxygens ("standing up") predominates. Based on evidence of strong attachment of DOPA to titanium dioxide from single molecule AFM (Lee, H. et al., Proc. Natl. Acad. Sci.2006, 103, 12999-12003) and studies of catechol adsorption, one or more of the DOPA attachments for each species is inner-sphere, the others are likely to be H-bonds. 相似文献