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91.
The spongy nickel oxide (SNO) was synthesized the solution combustion method. The SNO was selected as a promoter to boost the catalytic activity of nanoraspberry-like palladium (NRPd) toward electrooxidation of five light fuels (LFs): methanol, ethanol, formaldehyde, formic acid, and ethylene glycol. The X-ray powder diffraction, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy, and field emission scanning electron microscope techniques were used for the materials characterization. In comparison with nonpromoted Pd, the NRPd-SNO electrocatalyst shown an excellent efficiency in parameters like the electrochemical active surface area and anti-CO poisoning behavior. The turnover data and the parameters, including reaction order, activation energy, and the coefficients of electron transfer and diffusion, were evaluated for the each process of LFs electrooxidation. The outcome for NRPd-SNO activity toward LFs electrooxidation was compared to some reported electrodes. The SNO increases the removal of intermediates created in the oxidation of LFs that can poison the surface of palladium catalyst. This is due to the presence of the lattice oxygens in SNO structure and Ni switching between its high and low valances. The compatibility of the adsorption process of LFs on the surface of the NRPd-SNO catalyst with different isotherms was determined by studying the Tafel polarization and calculating the surface coverage.  相似文献   
92.
Pertussis toxin (PTX) is a required co-adjuvant for experimental autoimmune encephalomyelitis (EAE) induced by immunization with myelin antigen. However, PTX’s effects on EAE induced by the transfer of myelin-specific T helper cells is not known. Therefore, we investigated how PTX affects the Th17 transfer EAE model (Th17-EAE). We found that PTX significantly reduced Th17-EAE by inhibiting chemokine-receptor-dependent trafficking of Th17 cells. Strikingly, PTX also promoted the accumulation of B cells in the CNS, suggesting that PTX alters the disease toward a B-cell-dependent pathology. To determine the role of B cells, we compared the effects of PTX on Th17-EAE in wild-type (WT) and B-cell-deficient (µMT) mice. Without PTX treatment, disease severity was equivalent between WT and µMT mice. In contrast, with PTX treatment, the µMT mice had significantly less disease and a reduction in pathogenic Th17 cells in the CNS compared to the WT mice. In conclusion, this study shows that PTX inhibits the migration of pathogenic Th17 cells, while promoting the accumulation of pathogenic B cells in the CNS during Th17-EAE. These data provide useful methodological information for adoptive-transfer Th17-EAE and, furthermore, describe another important experimental system to study the pathogenic mechanisms of B cells in multiple sclerosis.  相似文献   
93.
Catalysis Letters - Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds...  相似文献   
94.
Water resource management problems are complex by nature and are often accompanied by many uncertainties, requiring suitable decision-making tools to solve. If decision makers cannot agree on a method of defining linguistic variables based on the fuzzy sets, favorable results and more accurate modeling can be achieved by using interval-valued fuzzy sets (IVFSs), which provide an additional degree of freedom to represent the uncertainty and fuzziness of the real world. Accordingly, this study is aimed to extend a fuzzy Delphi analytic hierarchy process (AHP) based on IVFSs (Interval-Valued Fuzzy Delphi AHP) and its application to large-scale rating problems related to water resource management. The proposed method is subsequently applied to select an optimal strategy for the rural water supply of Nohoor Village in northeast Iran, as a case study and actual water resource rating problem. According to sensitivity analyses of the results and a comparison of the results with a real project, the proposed method offers good outcomes for water resource rating problems.  相似文献   
95.
The Dokan Reservoir dam is a concrete cylindrical arch with gravity abutments, located on the Lesser Zab River about 60 km from the city of Sulaimani in north‐eastern Iraq. A bathymetric survey was conducted in November 2014 for a period of 10 days, using an echo sounder of 200‐kHz single beam. The survey results indicated an annual average sediment deposition of 3.8 million m3. Thirty‐two sediment samples were collected from the reservoir bed. The ratio of gravel, sand, silt and clay was 15:14:48:23, respectively. The reservoir bed is covered mainly with silt. The sediments are composed of silty clay (77.6%), silty sandy clay (10%), sandy gravely silty clay (1.2%) and gravely sandy silty clay (1%).  相似文献   
96.
Water Distribution Systems (WDSs) are indispensable infrastructures for urban societies. Due to vitality of continuous supply of drinking water in urban areas, it is necessary to have a performance evaluation and monitoring system to provide the expected level of security in water distribution systems. A main weakness point of these systems is the physical break of pipes which results in high level of water loss, pollution risk and public unsatisfactory. In this study, a framework is developed to increase physical water supply security in urban areas. For this purpose, a physical vulnerability index (PVI) is developed for evaluation of physical statues of water mains. In quantifying PVI, pipe characteristics and bedding soil specifications are considered. The importance of these factors on PVI is determined using Analytical Hierarchy Process (AHP). In system performance evaluation, the pipe role in system performance is incorporated regarding pipe location in WDS, distance of pipe from reservoir and average pressure of pipe. Then, System Physical Performance Index (SPVI) is evaluated. An optimization algorithm is employed to determine ways to improve the system performance through enhancing the physical condition of the pipe in the system at a minimum cost. The genetic algorithm is employed for solving the optimization model. A global sensitivity analysis method named FAST, is used for sensitivity analysis to incorporate the correlation between different parameters in analysis. The proposed framework is applied to a case study located in Tehran metropolitan area. The results of this study show the significant value of the proposed algorithm in supporting decision makers to better choose vulnerable pipes for rehabilitation practices in order to decrease system vulnerability against physical failures.  相似文献   
97.
Using hourly global radiation data at Quetta, Pakistan for 10 yr, an Autoregressive Moving Average (ARMA) process is fitted. Markov Transition Matrices have also been developed. These models are used for generating synthetic sequences for hourly radiations in MJ/m2 and that the generated sequences are compared with the observed data. We found the MTM approach relatively better as a simulator compared to ARMA modeling.  相似文献   
98.
In this article, the thermal post-buckling of shells of revolution under the action of uniform thermal load is investigated. To discretize the problem, the semi-analytical finite element method has been employed. The nonlinear equations are then solved by means of the Newton-Raphson algorithm in conjunction with the Arc length method. The effect of initial imperfection is also considered. The results obtained from the present analysis are compared to the published results in the literature to show the accuracy and robustness of the present method in predicting the nonlinear thermal buckling of shells of revolution.  相似文献   
99.
The effect of oxygen, hydrogen, and (oxygen + hydrogen) molecules adsorption on the structural and electrical properties of (8,0) carbon nanotube (CNT) are investigated through density functional theory. The obtained results indicate endothermical chemisorption of O2 on the nanotube surface with a large binding energy of about 598 meV and a significant charge transfer of about 0.43 e per molecule. It is discussed that the O2 chemisorption creates hole carries in the (8,0) carbon nanotube and thus increases the work function of the system. In the case of hydrogen molecule, a weak physisorption on the surface of CNT (∼−5 meV) is identified. The adsorption of H2 on CNT is also accompanied by hole doping and increment of the work function of the CNT, while the charge transfer between CNT and H2 is negligible. The band offsets in the H2-CNT junction are calculated to examine and describe the observed hole doping in this system. The effect of oxygenation of CNT on hydrogen adsorption is also investigated and the most favorable adsorption configuration is found and the related adsorption energy is calculated. It is argued that the oxygenation of CNT enhances the physisorption of hydrogen molecules. It is shown that hydrogen molecule adsorption on the oxidized CNT cancels hole doping and hence decreases the work function of the system.  相似文献   
100.
Prudent management of Iraqi water resources under climate change conditions requires plans to be based on actual figures of the storage capacity of existing reservoirs. With the absence of sediment flushing measures, the actual storage capacity of Dokan Reservoir (operated since 1959) has been affected by the amount of sediment delivered during its operational life leading to an undetermined reduction in its storage capacity. In consequence, there has not been an update on the dam's operational storage capacity curves. In this research, new operational curves were established for the reservoir based on a recent bathymetric survey undertaken in 2014. The reduction in reservoir capacity during the period between 1959 and 2014 was calculated by the mean of the difference between the designed storage capacity and the storage capacity which was concluded from the 2014 bathymetric survey. Moreover, the rate of sediment transported to the reservoir was calculated based on the overall quantities of accumulated sediment and the water discharge of the Lesser Zab River into the reservoir. The results indicate that the dam capacity is reduced by 25% due to sedimentation of an estimated volume of 367 million cubic metres at water level 480 m.a.s.l. The annual sedimentation rate was about 6.6 million cubic metres, and the sediment yield was estimated to be 701.2 t?km?3?year.  相似文献   
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