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111.
World Wide Web - In many cases, users are not familiar with their exact information needs while searching complicated data sources. This lack of understanding may cause the users to feel... 相似文献
112.
A conceptual design and statistical overview about passive direct methanol fuel cells that have been fabricated from 2002 to 2013, is performed [1–70]. The major components of passive DMFCs such as: active area, type of Nafion, catalyst loading on the anode and cathode side, characteristics and designs of current collectors (CC), and also the optimum methanol concentration which resulted in the best performance are categorized and studied statistically and individually. Finally, the best combination for the design and fabrication of a reliable passive DMFC is recommended. Obtained results indicated that a MEA with 4 cm2 active area, Nafion 117 and 4 mg/cm2 Pt/Ru at the anode and 2 mg/cm2 Pt black at the cathode (or 4 mg/cm2 Pt/Ru at the anode – 4 mg/cm2 Pt black at the cathode) as the catalyst loading, which is sandwiched between two stainless steel perforated current collectors that are coated by Pt (or Gold) could be a reliable design for a passive direct methanol single cell. 相似文献
113.
Abstract Each generation of programming languages has made applications easier to develop. In recent years, the use of fourth-generation languages (4GLs) has allowed many users, formerly alienated from the systems development process, to fulfill their own information needs. MIS professionals, however, have reacted negatively to the use of 4GLs. This article presents a survey of MIS professionals, who reveal their perceptions of the use and productivity of 4GLs as well as some of the obstacles that prevent them front using 4GLs in their organizations. 相似文献
114.
Manhal Abouzlam Régis Ouvrard Driss Mehdi Florence Pontlevoy Bertrand Gombert Nathalie Karpel Vel Leitner Sahidou Boukari 《Control Engineering Practice》2013,21(1):105-112
This paper deals with the control of a wastewater treatment pilot by catalytic ozonation. In general, catalytic ozonation processes operate with a deliberate ozone overproduction to obtain a treated water which respects discharge standards. But, in this case, the oxygen consumption is not optimal and the operating costs are important. The objective of this study focuses on the optimization of the catalytic ozonation reactor. A continuous-time transfer function model is identified to represent the pilot behavior, and an optimal control is proposed to obtain a significant abatement of the pollutant. In this application, the pollutant abatement is represented by the absorbance. 相似文献
115.
Alex Buchberger Harpinder Saini Kiarash Rahmani Eliato Azadeh Zare Ryan Merkley Yang Xu Julio Bernal Robert Ros Mehdi Nikkhah Dr. Nicholas Stephanopoulos 《Chembiochem : a European journal of chemical biology》2021,22(10):1755-1760
Biomaterials with dynamically tunable properties are critical for a range of applications in regenerative medicine and basic biology. In this work, we show the reversible control of gelatin methacrylate (GelMA) hydrogel stiffness through the use of DNA crosslinkers. We replaced some of the inter-GelMA crosslinks with double-stranded DNA, allowing for their removal through toehold-mediated strand displacement. The crosslinks could be restored by adding fresh dsDNA with complementary handles to those on the hydrogel. The elastic modulus (G’) of the hydrogels could be tuned between 500 and 1000 Pa, reversibly, over two cycles without degradation of performance. By functionalizing the gels with a second DNA strand, it was possible to control the crosslink density and a model ligand in an orthogonal fashion with two different displacement strands. Our results demonstrate the potential for DNA to reversibly control both stiffness and ligand presentation in a protein-based hydrogel, and will be useful for teasing apart the spatiotemporal behavior of encapsulated cells. 相似文献
116.
Computational Economics - This paper presents the numerical solution of the Black–Scholes partial differential equation (PDE) for the evaluation of European call and put options. The proposed... 相似文献
117.
In this study, a conventional steam power plant with two regenerative boilers is considered, and one of its boilers is replaced with parabolic solar dish collectors and storing the produced thermal energy by the phase change material (PCM) in a storage tank. The results show the necessity of the existence of an auxiliary fired‐gas boiler to provide constant load during the whole 24 hours. The performance of the proposed hybridized system is evaluated through energy and exergy analyses. It was demonstrated that substituting solar collectors with one of the boilers marginally lowers the energy efficiency but increases the exergy efficiency of the whole power plant up to 41.76%. Moreover, it is found out that this hybridization decreases the total irreversibility of the power plant in comparison with the base case, from 51.1 to 47.2 MW. The parametric analysis states that raising the mass flow rate of the heat transfer fluid in the solar collectors not only enhances the system performance but also increases the volume of the PCM tank. 相似文献
118.
Behnam Noorani Fatemeh Yazdian Zahra-Soheila Soheili Mehdi Shakibaie Shiva Rahmani 《国际聚合物材料杂志》2018,67(12):754-763
Damage of the retinal pigmented epithelial cells causes various diseases such as age-related macular degeneration in retinal tissue. Nowadays, scientists are attempting to replace lost retinal cells with healthy and efficient cells that provide better conditions for recovering and preventing blindness. In this study, gelatin/chitosan nanofibrous scaffolds with mean diameters of 180?nm were fabricated for subretinal space through electrospinning. Thickness and morphology of the gelatin–chitosan scaffolds were analyzed by scanning electron microscopy (SEM). The results showed that the high rate of degradation, i.e., 90% damage was obtained after 1 month. The cell viability of gelatin/chitosan nanofibers were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The SEM results of cultured RPE on gelatin/chitosan scaffolds showed the appropriate adhesion of cells on the substrate. The results of the identity of RPE cells cultured on the scaffolds indicated that a large number of cells strongly expressed RPE65 and cytokeratin 8/18. 相似文献
119.
Mehdi Ghorbani Gholamhosein Montazeri 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(17):2083-2093
To measure MMP, slim tube method is time consuming, especially for heavy oils. In this study, a strategy is considered to measure the MMP in one of the Iranian heavy oil reservoirs. The strategy steps were done through; partial data of slim tube, coupling numerical model (CNM), full slim tube, and VIT test. The results showed that CNM technique with two experimental data obtains the MMP value faster than running a full slim tube with low error result. However, VIT determined MMP faster and its results illustrated that miscibility pressure for heavy oil occurs at zero IFT, unlike light oils. 相似文献
120.