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Phase type delay distribution with PU return and sensing error in CR networks

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Journal of Central South University 2017年第10期24卷 2314-2321页

作者： Mohammad Reza Amini hemati Farzad Department of Electrical Engineering College of EngineeringBorujerd BranchIslamic Azad UniversityBorujerdIran

Many studies have been done in cognitive radios to maximize the network efficiency. There is always a trade-off between sensing and transmission time which has been addressed fully in the literature. There is also some missed idle times during the waiting phase when secondary user finds the channel busy. Therefore, the longer the transmission time is, the higher the successfully delivered bits would be and the higher the missed idle times in the waiting stage would be expected. In this work, we formulate these missed idle times to addressed this trade-off. Furthermore, interference due to PU re-occupancy is modelled in successful transmitted time and in collision probability. Moreover, we derive secondary user's packet delay distribution using phase type model at which retransmission due to collision results from both sensing error and PU re-occupancy is considered. Thanks to derived delay distribution, any statistical moments of delay could be found as a closed form mathematical expression. These moments can be used as constraints for applications with delay sensitive packets. Numerical results are given to clarify the network metrics. Finally, the optimized values for sensing and transmission time are computed using genetic algorithm in order to maximize access efficiency.

关键词： phase type distribution spectrum sensing cognitive radio access efficiency

Computational fluid dynamics simulation of gas dispersion in complex facilities using Kit Fox field experiments:Validation and statistical evaluation

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Chinese Journal of Chemical Engineering 2022年第4期35卷 412-423页

作者： Narjes hemati Alam Eslam Kashi Razieh Habibpour Department of Chemical Technologies Iranian Research Organization for Science and TechnologyP.O.Box 33535111TehranIran

Gas release and its dispersion is a major concern in chemical *** order to manage and mitigate the risk of gas dispersion and its consequences,it is necessary to predict gas dispersion behavior and its concentration at various locations upon ***,models and commercial packages such as Phast and ALOHA have been *** fluid dynamics(CFD)can be a useful tool to simulate gas dispersion in complex areas and *** validation of the models requires the employment of the experimental data from filed and wind tunnel *** appears that the use of the experimental data to validate the CFD method that only includes certain monitor points and not the entire domain can lead to unreliable results for the intended areas of *** this work,some of the trials of the Kit Fox field experiment,which provided a wide-range database for gas dispersion,were simulated by *** scenarios were considered with different mesh sizes,physical conditions,and types of *** results of the simulations were surveyed in the whole *** data matching each scenario was varied by the influence of the dominant displacement force(wind or diffusivity).Furthermore,the statistical parameters suggested for the heavy gas dispersion showed a dependency on the lower band of gas ***,they should be used with ***,the results and computation cost of the simulation could be affected by the chosen scenario,the location of the intended points,and the release type.

关键词： Gas dispersion simulation Computational fluid dynamics Complex terrain Obstructed flow

Removal of petroleum asphaltenes by improved activity of NiO nanoparticles supported on green AlPO-5 zeolite: Process optimization and adsorption isotherm

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Petroleum 2020年第2期6卷 182-188页

作者： Majid Mohammadi Mehdi Sedighi Meysam hemati Department of Energy Engineering Faculty of ScienceQom University of TechnologyQomIran Division of Energy Systems Department of Chemical EngineeringUniversity of QomQomIran Center of Environmental Research University of QomQomIran Department of Management Zanjan BranchIslamic Azad UniversityZanjanIran

Asphaltenes removal enhances the quality of the oil and facilitates the *** the present work,a NiO/AlPO-5 nanocomposite using green TMG was synthesized as a particular adsorbent for asphaltenes ***/AlPO-5 was characterized using FTIR,BET,TEM,and XRD *** Response Surface Method was used to optimize three important independent operating parameters,including D/C0[(g)adsorbent/(mg/L)initial](X1),initial pH(X2)and temperature(X3),to remove asphaltenes by the NiO/AlPO-5 nanocomposites in a model oil *** a CCD,a quadratic mathematical model formula was obtained to calculate asphaltene *** results revealed that the model showed valid agreement with the experimental results,with R2=*** optimum values for D/C0,pH as well as temperature would be 0.08[g/(mg/L)],3.39 and 298 K,*** was revealed that the optimal asphaltenes removal was 83.73%at the optimum *** isothermal models of Langmuir and Freundlich represented the asphaltenes adsorption on the new adsorbent with acceptable accuracy.

关键词： Asphaltene Removal Nanocomposite Optimization Adsorption

Comparison of sedative effectiveness of thiopental versus midazolam in reduction of shoulder dislocation

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World Journal of Emergency Medicine 2018年第2期9卷 125-129页

作者： Elnaz Vahidi Rezvan hemati Mehdi Momeni Amirhossein Jahanshir Morteza Saeedi Emergency Medicine Research Center Shariati Hospital Emergency Medicine Department Tehran University of Medical Sciences

BACKGROUND: Various sedative drugs have been proposed to control anxiety and agitation in shoulder dislocation, but none of them has been diagnosed as the best sedative and relaxant agent. The study aimed to compare the sedative effectiveness of thiopental versus midazolam in reduction of shoulder ***: A randomized double-blind controlled trail was performed in 80 patients with shoulder dislocation recruited from the emergency department. Ten patients were excluded and 70 patients were enrolled in the study. Case group received intravenous thiopental 2 mg/kg+2 μg/kg fentanyl while control group received intravenous midazolam 0.1 mg/kg+2 μg/kg fentanyl. Number of times, patients and physician's satisfaction, difficulty of procedure, degree of muscle relaxation, time of sedation and complete recovery, number of patients with apnea episode, O2 saturation, patient's pain score and adverse events were all ***: Muscular tone had significant difference between the two groups(P-value=0.014) and thiopental was more muscle relaxant than midazolam. Replacement of shoulder dislocation in thiopental group was easier than midazolam group(P-value=0.043). There was no need to use multiple methods of reduction in either group. Before drug infusion the mean±SD VAS scores were 8.37±2.21 in the midazolam group(A) and 8.94±1.78 in the thiopental group(B); mean difference 0.57, 95% CI= –0.38 to 1.52. After completion of the procedure, the mean±SD VAS scores in group(A) and(B) were 3.20±1.30 vs. 3.65±1.30; mean difference –0.45, 95% CI= –1.07 to ***: Thiopental might be more effective and relaxant than midazolam for reduction of shoulder dislocation.

关键词： Thiopental Shoulder dislocation Midazolam Emergency medicine

Effects of polyethyleneimine-functionalized MCM-41 on flame retardancy and thermal stability of polyvinyl alcohol

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Particuology 2015年第2期13卷 14-21页

作者： Meisam Shabanian Mehdi Khoobi Farideh hemati Hossein Ali Khonakdar Khalil Faghihi Udo Wagenknecht Seyed esmaeil Sadat ebrahimia Abbas Shafiee Department of Medicinal Chemistry Faculty of Pharmacy and Pharmaceutical Sciences Research CenterTehran University of Medical Sciences Faculty of Chemistry and Petrochemical Engineering Standard Research Institute(SRI) Department of Chemistry Faculty of ScienceArak University Iran Polymer and Petrochemical Institute Leibniz-Institute of Polymer Research

Hyperbranched polyethylenimine （PEl）-functionalized mesoporous silica （MCM@PEI） was synthesized and used to produce poly（vinyl alcohol）（PVA） nanocomposites. The modified nanofiller was charac- terized with infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption. When compared with pure meso- porous silica （MCM）, the MCM@PEI nanoparticles exhibited better dispersion in the PVA matrix. The effects of MCM@PEI on the thermal and flame properties of PVA nanocomposites were also studied. Improvement in the thermal properties was confirmed by enhanced thermal stability and char yield. Incorporation of MCM@PEI in PVA led to a significant drop in the heat release rate and the total heat release.

关键词： Nanocomposite PVA Nanofiller MCM-41

Detection of small bowel tumor in wireless capsule endoscopy images using an adaptive neuro-fuzzy inference system

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The Journal of Biomedical Research 2017年第5期31卷 419-427页

作者： Mahdi Alizadeh Omid Haji Maghsoudi Kaveh Sharzehi Hamid Reza hemati Alireza Kamali Asl Alireza Talebpour Department of Bioengineering Temple University Philadelphia PAl9121 USA Department of Medicine Section of Gastroenterology School of Medicine Temple University Philadelphia PA 19140. USA Department of Radiation Medicine Engineering ShahidBeheshti University Tehran *** Iran. Department of Electrical and Computer Engineering ShahidBeheshti University Tehran *** Iran.

Automatic diagnosis tool helps physicians to evaluate capsule endoscopic examinations faster and more *** purpose of this study was to evaluate the validity and reliability of an automatic post-processing method for identifying and classifying wireless capsule endoscopic images, and investigate statistical measures to differentiate normal and abnormal images. The proposed technique consists of two main stages, namely, feature extraction and classification. Primarily, 32 features incorporating four statistical measures(contrast, correlation, homogeneity and energy) calculated from co-occurrence metrics were computed. Then, mutual information was used to select features with maximal dependence on the target class and with minimal redundancy between features. Finally, a trained classifier, adaptive neuro-fuzzy interface system was implemented to classify endoscopic images into tumor, healthy and unhealthy classes. Classification accuracy of 94.2% was obtained using the proposed pipeline. Such techniques are valuable for accurate detection characterization and interpretation of endoscopic images.

关键词： adaptive neuro-fuzzy inference system co-occurrence matrix wireless capsule endoscopy texture feature

Biomass Vapogasification in Fluidized Bed： Modelling of Char Population Balance and Experimental Validation

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Journal of Chemistry and Chemical Engineering 2010年第12期4卷 38-51页

作者： Marc Detoumay Mehrdji hemati Chemical Engineering Laboratory U.M.R. 5503 ENSIACET 4 all~e Emile Monso-BP 84234 31432 Toulouse Cedex 4 France

The article presents a population balance model by mass developed for studying char gasification by steam occuring in a fluidized bed. The model has been validated by comparison with existing theoretical and experimental cases. Its main goal is to have a better understanding on particles size distribution behaviour during operation of the fluidized bed, and in particular to be applied on the case of Fast Internally Circulating Fluidized Beds for char gasification. Results have shown that the initial properties of the fluidized bed particles （bed and size distribution） are almost not involved in the steady state obtained in continous operation, which is excusively dependent on the properties of the fed particles flow rate and size distribution, the withdrawal flow rate and the reaction properties. Morevoer, it has been proven that the steady state fluidized bed mass and size distribution may be theroretically controlled by an adequate choice of feeding and withdrawal flow rates.

关键词： Population balance size distribution steam gasification biomass char particles.

Soil algae enzymes and their biotechnological applications

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Systems Microbiology and Biomanufacturing 2022年第4期2卷 589-606页

作者： Mohammad Amin Shoarnaghavi Arti Mishra Arian Amirifar Smruthi Sagarika Mahapatra Khatereh Nobaharan Arash hemati Behnam Asgari Lajayer Tess Astatkie Department of Biology Islamic Azad University of UrmiaUrmiaIran Amity Institute of Microbial Technology Amity UniversityNoidaUttar Pradesh 201303India Indira Gandhi Agricultural University RaipurChhattisgarh 492012India 12/9 Browns Avenue RingwoodMelbourneVIC 3134Australia Department of Soil Science Faculty of AgricultureUniversity of TabrizTabrizIran Faculty of Agriculture Dalhousie UniversityTruroNS B2N 5E3Canada

At present time,most of the enzymes are derived from biological sources,including plants,animals,microalgae,algae,and other *** enzymes,among the others,account for the biggest part of application and demand in *** enzymes from soil microorganisms are very essential not only for soil fertility but also for biotechnological *** enzymes from microalage,comprising Amylase,Carbonic anhydrase,Galactosidase,Laccase,L-Asparaginase,Lipase,Peroxidase,Phytase,Protease,and Superoxide dismutase attract a considerable amount of attention for themselves in various *** of the enzymes mentioned above have a great potential for their application in biotechnology and *** of such enzymes are known for their versatility and countless applications in various fields;thus,performing research on these enzymes in the future would be *** review paper presents an overview of the potential of soil algae enzymes in fields like biotechnology,medicine and agriculture,and also provides areas for advancement in researches related to this field.

关键词： Soil algae Microalgae Enzymes Biotechnological applications

New vision on the Relationship between Income and Water Withdrawal in Industry Sector

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Natural Resources 2011年第3期2卷 191-196页

作者： Abdolnaser hemati Mohsen Mehrara Ali Sayehmiri 不详

This paper investigates the relationship between industrial water withdrawal (IWW) and income in selected world countries. The issue is addressed by means of a smooth transition regression (STR) model on cross section data of 132 countries in 2006. The results confirm the nonlinearity of the link between IWW and income. According to the results, the income elasticity of IWW is a bell-shaped curve. Therefore, the policies and management processes in water sector including water allocation between activities and reigns should take into account the development degree and also focus on income level, water scarcity and the economic, social and ecological structure in each country.

关键词： Water-Income STR NRBEKC Elasticity Socio-Economic Structure