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31.
Schmitz Joy M.; Rhoades Howard M.; Elk Ronith; Creson Daniel; Hussein Iman; Grabowski John 《Canadian Metallurgical Quarterly》1998,6(2):162
Two studies examined contingent take-home medication doses during treatment of opiate or cocaine dependence. In the first study, methadone maintenance patients were randomly assigned to one of two 8-week baseline take-home (TH) conditions differing in frequency of clinic visits per week. This was followed by a 12-week contingency management (CM) procedure in which frequent THs resulted from drug-free urines. Participants receiving more frequent THs during baseline had lower illicit drug use during the first 6 weeks of CM. In the second study, fluoxetine (0-, 20-, 40-mg) TH doses were similarly contingent in treatment of cocaine dependence. The 40-mg group used less cocaine during contingency than did other groups. The combination of fluoxetine and environmental contingencies may produce benefit where neither alone is sufficient. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
Multirate systems are abundant in industry. In this paper, the problem studied is designing a residual generator for fault detection based on multirate sampled data. The key new feature of such a residual generator is that it operates at a fast rate for prompt fault detection. The design is based on optimizing a performance index to obtain an optimal parity space based residual generator. The lifting technique is used to convert the time-varying multirate design problem into a time-invariant one with a causality constraint for implementability. A procedure for computing an explicit optimal, causal solution is proposed. The advantages of this design are shown through an example. 相似文献
33.
The electrochemical behavior of low carbon steel (API 5L grade B) in 1 mol/L HCI solution with different concentrations of N,Nr-bis(4-formylphenol)-trimethylenediamine Schiff base was studied by electrochemical techniques and density functional theory analysis. The inhibition efficiency was found to increase with increasing inhibitor concentration and decreased with increasing temperature. The high inhibition efficiency was attributed to the blocking of active sites by adsorption of inhibitor molecules on the steel surface. Thermodynamic parameters for the adsorption and activation processes were determined. Galvanostatic polarization data indicated that Schiff base act as a mixed-type inhibitor and the adsorption isotherm obeyed the Langmuir adsorption isotherm. Results obtained from quantum chemical studies show excellent correlations between the quantum chemical parameters and the experimental inhibition efficiencies using density functional theory at the B3LYP/6-31G(d,p) and B3LYP/3-21G basis set levels and ab initio calculations using HF/6-31G(d,p) and HF/3-21G methods. 相似文献
34.
Reza Abedini Iman Zanganeh Mohammad Mohagheghian 《Journal of Phase Equilibria and Diffusion》2011,32(2):105-114
Since it is not always possible to carry out experiments at all desired temperatures and pressures, generally thermodynamic models based on equations of state are used for estimation of vapor-liquid equilibrium. In this work, a method using artificial neural network (ANN) was designed and applied to simulate and estimate the VLE for the binary asymmetric systems containing CO2 and Alcohols. The vapor-liquid equilibrium data of six systems include (CO2-methanol), (CO2-ethanol), (CO2-1-butanol), (CO2-2-butanol), (CO2-1-pentanol) and (CO2-2-pentanol) were used to developed the ANN for simulation of VLE. The results when using a developed ANN model or other methods such as SRK equations of state with LCVM, PSRK, WS, were compared with experimental data at various temperatures and pressures. Finally, it was observed that there is more qualitative and quantitative conformity between ANN model results and experimental data. Furthermore, the developed ANN model showed more accurate estimation over wide range of experimental conditions. 相似文献
35.
Iman Ahmadianfar Arvin Samadi-Koucheksaraee Omid Bozorg-Haddad 《Water Resources Management》2017,31(14):4375-4397
Deriving the optimal policies of hydropower multi-reservoir systems is a nonlinear and high-dimensional problem which makes it difficult to achieve the global or near global optimal solution. In order to optimally solve the problem effectively, development of optimization methods with the purpose of optimizing reservoir operation is indispensable as well as inevitable. This paper introduces an enhanced differential evolution (EDE) algorithm to enhance the exploration and exploitation abilities of the original differential evolution (DE) algorithm. The EDE algorithm is first applied to minimize two benchmark functions (Ackley and Shifted Schwefel). In addition, a real world two-reservoir hydropower optimization problem and a large scale benchmark problem, namely ten-reservoir problem, were considered to indicate the effectiveness of the EDE. The performance of the EDE was compared with the original DE to solve the three optimization problems. The results demonstrate that the EDE would have a powerful global ability and faster convergence than the original DE to solve the two benchmark functions. In the 10-reservoir optimization problem, the EDE proved to be much more functional to reach optimal or near optimal solution and to be effective in terms of convergence rate, standard deviation, the best, average and worst values of objective function than the original DE. Also, In the case of two-reservoir system, the best values of the objective function obtained 93.86 and 101.09 for EDE and DE respectively. Based on the results, it can be stated that the most important reason to improve the performance of the EDE algorithm is the promotion of local and global search abilities of the DE algorithm using the number of novel operators. Also, the results of these three problems corroborated the superior performance, the high efficiency and robustness of the EDE to optimize complex and large scale multi-reservoir operation problems. 相似文献
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37.
The effect of ZIF-90 particle in Pebax/Psf composite membrane on the transport properties of CO2, CH4 and N2 gases by Molecular Dynamics Simulation method 下载免费PDF全文
Nowadays, mixed matrix membranes (MMMs) have considered by many researchers to overcome the problems of polymeric membranes. In addition, molecular dynamics (MD) and Monte Carlo (MC) simulation Methods are suitable tools for studying transport properties and morphology in MMMs. For this purpose, in this study using material studio 2017 (MS) software, the transport properties of CO2, CH4 and N2 in Pebax, Psf neat Pebax/Psf composite and Pebax/Psf composite filled with ZIF-90 particles have been investigated. By adding Psf to Pebax matrix, the selectivity of CO2/CH4 and CO2/N2 gases has significantly increased. In addition, adding ZIF-90 particles to the Pebax/Psf composite increased the permeability of CO2, CH4 and N2 compared to neat and composite membranes. The morphological properties of the membranes, such as the fractional free volume (FFV), radial distribution function (RDF), glass transition temperature (TG), X-ray diffraction (XRD) and equilibrium density have calculated and acceptable results have obtained. 相似文献
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39.
Gabriel Falzone Iman Mehdipour Narayanan Neithalath Mathieu Bauchy Dante Simonetti Gaurav Sant 《American Institute of Chemical Engineers》2021,67(5):e17160
Portlandite (Ca(OH)2; also known as calcium hydroxide or hydrated lime), an archetypal alkaline solid, interacts with carbon dioxide (CO2) via a classic acid–base “carbonation” reaction to produce a salt (calcium carbonate: CaCO3) that functions as a low-carbon cementation agent, and water. Herein, we revisit the effects of reaction temperature, relative humidity (RH), and CO2 concentration on the carbonation of portlandite in the form of finely divided particulates and compacted monoliths. Special focus is paid to uncover the influences of the moisture state (i.e., the presence of adsorbed and/or liquid water), moisture content and the surface area-to-volume ratio (sa/v, mm−1) of reactants on the extent of carbonation. In general, increasing RH more significantly impacts the rate and thermodynamics of carbonation reactions, leading to high(er) conversion regardless of prior exposure history. This mitigated the effects (if any) of allegedly denser, less porous carbonate surface layers formed at lower RH. In monolithic compacts, microstructural (i.e., mass-transfer) constraints particularly hindered the progress of carbonation due to pore blocking by liquid water in compacts with limited surface area to volume ratios. These mechanistic insights into portlandite's carbonation inform processing routes for the production of cementation agents that seek to utilize CO2 borne in dilute (≤30 mol%) post-combustion flue gas streams. 相似文献
40.
There exist only a few papers in the literature which target the problem of “proposing a secure designated server identity-based encryption with keyword search scheme.” In this paper, we prove that they all suffer from security issues, and therefore, this challenging problem still remains open. 相似文献