检索结果-南通市图书馆

Frontiers in Energy 2022年第5期16卷 862-875页

作者： Hassan HAJABDOLLAHI mohammad SHAFIEY DEHAJ Babak MASOUMPOUR mohammad ataeiZADEH Department of Mechanical Engineering Vali-e-Asr University of RafsanjanRafsanjan ***Iran

The present work aims to investigate the influence of extended surfaces(fins)on the multi-objective optimization of a tubular heat exchanger network(THEN).An increase in the heat transfer area using various extended surfaces(fins)to enhance the performance of the heat exchanger was used while considering the effectiveness and total heat transfer area as two objective *** addition to the simulation of simple fins,a new set of fins,called constructal fins,was designed based on the constructal *** heat exchanger network design parameters were chosen as optimization variables,and optimization results were achieved in such a way as to enhance the effectiveness and decrease the total heat transfer *** results show the importance of constructal fins in improving the objective functions of heat *** instance,the simple fins case enhances the effectiveness by up to 5.3%compared to that without fins(usual heat exchanger)while using constructal fins,in addition to the 7%increment of effectiveness,reduces the total heat transfer area by 9.47%.In order to optimize the heat exchanger,the heat transfer rate and cold fluid temperature must increase,and at the same time,the hot exiting fluid temperature should decrease at the same constant total heat transfer area,which is higher in the constructal fins ***,optimized design variables were studied for different cases,and the effects of various fins were reported.

关键词： constructal theory extended surface effectiveness total heat transfer area multi-objective optimization

A novel adaptive finite-time controller for synchronizing chaotic gyros with nonlinear inputs

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第9期20卷 86-91页

作者： mohammad Pourmahmood Aghababa Young Researchers Club Ahar BranchIslamic Azad UniversityAhar 54516Iran

In this paper, the problem of the finite-time synchronization of two uncertain chaotic gyros is discussed. The parameters of both the master and the slave gyros are assumed to be unknown in advance. The effects of model uncertainties and input nonlinearities are also taken into account. An appropriate adaptation law is proposed to tackle the gyros＇ unknown parameters. Based on the adaptation law and the finite-time control technique, proper control laws are introduced to ensure that the trajectories of the slave gyro converge to the trajectories of the master gyro in a given finite time. Simulation results show the applicability and the efficiency of the proposed finite-time controller.

关键词： chaotic gyro finite-time synchronization model uncertainty nonlinear input

Eco-friendly green synthesis of novel magnetic Fe3O4/SiO2/ZnO-Pr6O11 nanocomposites for photocatalytic degradation of organic pollutant

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2020年第1期38卷 13-20页

作者： mohammad Ali Ebrahimzadeh Sobhan Mortazavi-Derazkola mohammad Ali Zazouli Pharmaceutical Sciences Research Center Hemoglobinopathy Institute and Department of Medicinal ChemistrySchool of PharmacyMazandaran University of Medical ScienceSariP.O.Box 48471-93698Iran Department of Environmental Health Engineering Health Science Research CenterFaculty of HealthMazandaran University of Medical ScienceSariP.O.Box 48471-16548Iran

This study reports the successful so nochemical synthesis of novel Fe3O4/SiO2/ZnO-Pr6O11(Fe/Si/Zn-Pr6O11) nanocomposites using fructose as a green capping *** influence of various parameters containing capping agent,power and time of ultrasound irradiation was investigated to reach optimum morphology and size *** products obtained were characterized by transmission electron microscopy(TEM),UV/Vis diffuse reflectance spectroscopy(DRS),Fourier transform infrared spectra(FT-IR),vibration sample magnetometer(VSM),scanning electron microscopy(SEM),energy dispersive X-ray microanalysis(EDS) and X-ray diffraction(XRD).The Fe3O4/SiO2/ZnO-Pr6O11 nanocomposites display remarkably enhanced photocatalytic activity towards rhodamine b degradation(89.6%)and Congo red(84.7%) under UV irradiation compared with the other *** results illustrate that the photocatalytic efficiency of magnetic nanocomposites is very much higher than pure *** photocatalyst still has good stability after five successive ***,these recyclable nanocomposites can play a role in the treatment of both industrial and domestic contaminated water.

关键词： Sonochemical synthesis Nanocomposite Photocatalysis Electron microscopy Rhodamine b Praseodymium oxide

Micromechanical simulation and experimental investigation of aluminum-based nanocomposites

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第1期17卷 196-201页

作者： mohammad Javad Ghasemi mohammad Silani Ali Maleki Mostafa Jamshidian Department of Mechanical Engineering Isfahan University of TechnologyIsfahan84156-83111Iran

Ceramic reinforced metal matrix nanocomposites are widely used in aerospace and auto industries due to their enhanced mechanical and physical *** this research,we investigate the mechanical properties of aluminum/Nano-silica composites through experiments and ***/Nanosilica composite samples with different weight percentages of silica nanoparticles are prepared via powder *** this method,Nano-silica and aluminum powders are mixed and compressed in a mold,followed by sintering at high *** tensile testing of the nanocomposite samples shows that adding one percent of Nano-silica causes a considerable increase in mechanical properties of nanocomposite compared to pure aluminum.A computational micromechanical model,based on a representative volume element of aluminum/silica nanocomposite,is developed in a commercial finite element *** model employs an elastoplastic material model along with a ductile damage model for aluminum matrix and linear elastic model for nano-silica *** careful determination of model parameters from the experimental results of pure aluminum samples prepared by powder metallurgy,the proposed computational model has shown satisfactory agreement with *** validated computational model can be used to perform a parametric study to optimize the microstructure of nanocomposite for enhanced mechanical properties.

关键词： Aluminum/nano-silica composites Powder metallurgy Micromechanics

An experimental approach for measuring carbon dioxide diffusion coefficient in water and oil under supercritical conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2021年第6期34卷 160-170页

作者： mohammad Sadegh Sharafi Mehdi Ghasemi mohammad Ahmadi Alireza Kazemi Department of Petroleum Engineering Amirkabir University of Technology–Tehran PolytechnicIran

Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into *** main complexity of indirect techniques such as pressure decay method is interpreting early pressure-time data which strongly affected by incubation period effect or convective *** the current approach,accurate apparatus and precise experimental setup including a high pressure and temperature PVT cell,a high precision Sanchez pump,heating and recording sub-system are implemented and a novel data analysis procedure is applied to modify pressure decay *** effect of incubation period is reduced remarkably and diffusion coefficient of carbon dioxide in water in wide range of pressures and temperatures is determined and the effects of temperature,pressure and carbon dioxide phase alteration from gas to supercritical are investigated and the value of uncertainty is ***,diffusion coefficient of CO_(2) and methane in an oil sample from one of the Iranian southwest oil formations is determined precisely using the experimental approach while no incubation period is *** results showed that incubation period duration decreases with increasing diffusion ***,when CO_(2) state is gas,rate of increasing diffusion coefficient with pressure is decreased with temperature and when CO_(2) state is supercritical,the rate of increasing diffusion coefficient with pressure is decreased significantly.

关键词： Diffusion coefficient Modified pressure decay method Incubation period Solubility uncertainty

Effect of Y_2O_3 on the crystallization kinetics of TiO_2 nucleated LAS glass for the production of nanocrystalline transparent glass ceramics

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 450-455页

作者： mohammad Sadegh Shakeri Materials and Energy Research Center (MERC) P.O. Box 31779-83634KarajIran

Crystallization kinetics of metastable B-quartz solid solution as a desirable phase for the production of trans- parent lithium aluminosilicate （LAS） glass ceramics was investigated in the presence of Y203. Accordingly, differential thermal analysis scans were performed thoroughly to study the mechanism of crystallization kinetics. The aim of this investigation is to discover the complicated mechanism of crystallization process in the presence of co-additives and ac- cordingly find a way for increasing the transparency of glass ceramics. It is shown that the bulk （3D） growth is intensively increased by the enhancement of Y203. Then again, reducing nucleation and increasing growth mechanisms were recog- nized for the LAS system in the presence of Y2O3. Results of the investigation illustrate that when co-additives are added to glasses, it is necessary to nucleate the optical component separately before the growth process.

关键词： glass ceramics lithium aluminosilicate yttria crystallization kinetics nanocrystals transparency

Design of an adaptive finite-time controller for synchronization of two identical/different non-autonomous chaotic flywheel governor systems

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第3期21卷 101-111页

作者： mohammad Pourmahmood Aghababa Electrical Engineering Department Urmia University of Technology

The centrifugal flywheel governor （CFG） is a mechanical device that automatically controls the speed of an engine and avoids the damage caused by sudden change of load torque. It has been shown that this system exhibits very rich and complex dynamics such as chaos. This paper investigates the problem of robust finite-time synchronization of non-autonomous chaotic CFGs. The effects of unknown parameters, model uncertainties and external disturbances are fully taken into account. First, it is assumed that the parameters of both master and slave CFGs have the same value and a suitable adaptive finite-time controller is designed. Second, two CFGs are synchronized with the parameters of different values via a robust adaptive finite-time control approach. Finally, some numerical simulations are used to demonstrate the effectiveness and robustness of the proposed finite-time controllers.

关键词： finite-time controller chaos synchronization non-autonomous centrifugal flywheel gov-ernor chaotic system

The sol-gel derived Co-Mn/TiO_2 catalysts for light olefins production

在线全文

学校读者我要写书评

暂无评论

燃料化学学报 2014年第2期42卷 212-218页

作者： mohammad Mehdi Khodaei Mostafa Feyzi Jahangir Shahmoradi mohammad Joshaghani Faculty of Chemistry Razi University

在这个研究工作，二 30%(Co-Mn )/TiO2 催化剂用大音阶的第五音胶化(催化剂 A ) 和一起沉淀(催化剂 B ) 被准备方法。到在 Fischer-Tropsch 合成(英尺) 的 C24 轻石蜡的活动和选择在不同运作的条件下面在一个改正床反应堆被学习了。这... 详细信息

在这个研究工作，二 30%(Co-Mn )/TiO2 催化剂用大音阶的第五音胶化(催化剂 A ) 和一起沉淀(催化剂 B ) 被准备方法。到在 Fischer-Tropsch 合成(英尺) 的 C24 轻石蜡的活动和选择在不同运作的条件下面在一个改正床反应堆被学习了。这些运作的条件是：温度

关键词： Fischer-Tropsch synthesis light olefins characterization

Ultrasensitive and selective 4-aminophenol chemical sensor development based on nickel oxide nanoparticles decorated carbon nanotube nanocomposites for green environment

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2017年第3期29卷 27-38页

作者： mohammad Musarraf Hussain Chemistry Department Faculty of ScienceKing Abdulaziz UniversityJeddah 21589P.O.Box 80203Saudi Arabia Center of Excellence for Advanced Material Research(CEAMR) King Abdulaziz UniversityJeddah 21589P.O.Box 80203Saudi Arabia

Nickel oxide nanoparticles decorated carbon nanotube nanocomposites （*** NCs） were prepared in a basic medium by using facile wet-chemical routes. The optical, morphological, and structural properties of *** NCs were characterized using Fourier transformed infra-red （FT-IR）, Ultra-violet visible （UV/Vis） spectroscopy, field-emission scanning electron microscopy （FESEM）, X-ray energy dispersed spectroscopy （XEDS）, X-ray photoelectron spectroscopy （XPS）, and powder X-ray diffraction （XRD） methods. Selective 4-aminophenol （4-AP） chemical sensor was developed by a fiat glassy carbon electrode （GCE, surface area： 0.0316 cm2） fabricated with a thin-layer of NCs. Electrochemical responses including higher sensitivity, large dynamic range （LDR）, limit of detection （LOD）, and long-term stability towards 4-AP were obtained using the fabricated chemical sensors. The calibration curve was found linear （R2 = 0.914） over a wide range of 4-AP concentration （0.1 nmol/L-0.1 tool/L）. In perspective of slope （2 x 10.5 gA/gM）, LOD and sensitivity were calculated as 15.0 ＋ 0.1 pM and -6.33 - 10.4 gA/（***） respectively. The synthesized *** NCs using a wet-chemical method is a significant route for the development of ultrasensitive and selective phenolic sensor based on nano-materials for environmental toxic substances. It is suggested that a pioneer and selective development of 4-AP sensitive sensor using *** NCs by a facile and reliable current us voltage （I-V） method for the major application of toxic agents in biological, green environmental, and health-care fields in near future.

关键词： NiO decorated CNT nanocomposltesOptical evaluationFabricationSensitivity4-AminophenolI-V method

Quality of sleep and its determinants among people with type 2 diabetes mellitus in Northwest of Iran

在线全文

学校读者我要写书评

暂无评论

World Journal of Diabetes 2017年第7期8卷 358-364页

作者： Seyed Morteza Shamshirgaran Jafar ataei Ayyoub Malek Manochehr Iranparvar-Alamdari Nayyereh Aminisani Department of Statistics and Epidemiology School of Health Sciences Tabriz University of Medical Sciences Injury Epidemiology Prevention Research Center Tabriz University of Medical Sciences Khalkhal Health Center School of Khalkhal Medical Sciences Ardabil University of Medical Sciences Research Center of Psychiatry and Behavioral Sciences Tabriz University of Medical Sciences Department of Internal Medicine School of Medicine Ardabil University of Medical Sciences

AIM To examine sleep quality and its determinants among people with type 2 diabetes mellitus(T2DM).METHODS This is a cross-sectional study conducted among diabetic patients referring to Ardabil diabetes clinic in Northwest of Iran. Information on sleep quality was collected using Pittsburg Sleep Quality Index(PSQI). A questionnaire was used to collect data on sociodemographic lifestyle factors and psychological distress. This questionnaire was completed through an interview, and clinical information was extracted from patient's record. Data analysis was done using SPSS software version 23 and univariate andmultivariate *** Study participants consist of 256 people with T2 DM the majority of whom were women(70%), and mean age of participants was 54.06 ± 9.09. The mean of total score of PSQI was 5.56 ± 3.34. Relative to younger age group, the middle-aged people with T2 DM were twice more likely to be poor sleeper; the adjusted OR was 2.03(95%CI: 1.01-4.08); and those with longer duration of diabetes were about 1.8 times more likely to report poor quality of sleep(ORadj = 1.77, 95%CI: 0.98-3.13). Participants with cholesterol level ≥ 240 mg/dL were about twice more likely to be poor sleeper(ORadj = 1.99, 95%CI: 1.01-3.94). The odds of being poor sleeper increased as the level of distress increased(1.84-4.09).CONCLUSION As indicated by the results of the present study, some factors including age, duration of disease, psychological distress and high level of cholesterol were independently associated with poor sleep quality.

关键词： Type 2 diabetes mellitus Lifestyle Pittsburg Sleep Quality Index Hypercholesterolemia Psychological distress