检索结果-南通市图书馆

Overall Assessment of Heat Transfer for a Rarefied Flow in a Microchannel with Obstacles Using Lattice Boltzmann Method

引用

工程与科学中的计算机建模(英文) 2024年第1期138卷 273-299页

作者： Siham Hammid Khatir Naima Omolayo M.Ikumapayi Cheikh Kezrane Abdelkrim Liazid Jihad Asad Mokdad Hayawi Rahman Farhan Lafta Rashid Naseer ali Hussien Younes Menni Laboratory of Development in Mechanics and Materials(LDMM) Zian Achour UniversityDjelfaPB 3117Algeria Department of Technology University Center Salhi Ahmed Naama(Ctr.Univ.Naama)P.O.Box 66Naama45000Algeria Department of Mechanical and Mechatronics Engineering Afe Babalola University Ado Ekiti360101Nigeria Departement of Physics Faculty of ScienceAbou Bekr Belkaid UniversityTlemcen13000Algeria Department of Physics Faculty of Applied SciencesPalestine Technical University-KadoorieTulkarmPalestine Aeronautical Technical Engineering Al-Farahidi UniversityBaghdad10011Iraq Mechanical Engineering Department University of KerbalaKarbala56001Iraq Information and Communication Technology Research Group Scientific Research CenterAl-Ayen UniversityThi-QarIraq National University of Science and Technology Dhi QarIraq

The objective of this investigation is to assess the effect of obstacles on numerical heat transfer and fluid flow momentum in a rectangular microchannel(MC).Two distinct configurations were studied:one without obstacles and the other with alternating obstacles placed on the upper and lower *** research utilized the thermal lattice Boltzmann method(LBM),which solves the energy and momentum equations of fluids with the BGK approximation,implemented in a Python coding *** jump and slip velocity conditions were utilized in the simulation for the MC and extended to all obstacle *** study aims to analyze the rarefaction effect,with Knudsen numbers(Kn)of 0.012,0.02,and *** outcomes indicate that rarefaction has a significant impact on the velocity and temperature *** presence of nine obstacles led to slower fluid movement inside the microchannel MC,resulting in faster cooling at the *** MCs with obstacles,the rarefaction effect plays a crucial role in decreasing the Nusselt number(Nu)and skin friction coefficient(Cf).Furthermore,the study demonstrated that the obstacles played a crucial role in boosting fluid flow and heat transfer in the *** findings suggest that the examined configurations could have potential applications as cooling technologies in micro-electro-mechanical systems and microdevice applications.

关键词： Microfluid rarefied flow LBM microchannel Knudsen number numerical simulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Modeling the rate of corrosion of carbon steel using activated diethanolamine solutions for CO2 absorption

引用

Chinese Journal of Chemical Engineering 2020年第8期28卷 2099-2110页

作者： Lubna Ghalib ahmed Abdulkareem Brahim Si ali Shaukat ali Mazari Materials Engineering Department Mustansiriyah UniversityBaghdad 14022Iraq Mathematics Science Directorate General of Education Rusafa 1BaghdadIraq Department of Chemical Engineering University of Malaya50603 Kuala LumpurMalaysia Department of Chemical Engineering Dawood University of Engineering and TechnologyKarachi 74800Pakistan

A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethanolamine(DEA)aqueous *** developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature,activator concentration,CO2 loading and *** study consists of two major models:Vapor–liquid Equilibrium(VLE)model and electrochemical corrosion *** electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk *** results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of *** increase in concentration of activator,increases the rate of corrosion of carbon steel in mixtures of activated DEA.

关键词： CO2 capture CO2 corrosion Carbon steel Diethanolamine Piperazine Electrochemical model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis of Factors that Affect Government Digitization:A Pilot Case Study of Pakistan

引用

Computers, Materials & Continua 2021年第1期66卷 291-301页

作者： Salman ahmed Muhammad ali Khan Department of Computer Systems Engineering University of Engineering&TechnologyPeshawarPakistan

One of the greatest factors that affects the economic condition of a country is its *** the model of good governance,the primary elements for stronger institution include efficiency,transparency,and accountability;and technology plays a major role in improving these ***,there are myriad of challenges when it comes to practical integration of technology in these institutions for *** is more challenging when a country is developing and one that is already weak *** is also important to mention that the challenges of digitization in public sector is not limited to developing countries *** is equally challenging,even today,in already developed countries to digitally transform their public institutions for improved policymaking and for responsive service *** factors contribute to the failure of such digitization initiatives,more so within developing *** the purpose of this paper is to identify those factors,to measure the significance of each of those factors,and to realize and overcome *** research considered the case study of Pakistan;however,the results are very likely to match the conditions of other developing regions around the *** questionnaires and interviews,valuable feedback was gathered from up to 25 senior government officers that are closely associated with digitization initiatives in public *** feedback to the questions were overall *** results indicate the most significant of factors that affect government digitization in this developing region,including some factors that were not expected.

关键词： E-governance government digitization information management sustainability

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Control of Wave Propagation and Effect of Kerr Nonlinearity on Group Index

引用

Communications in Theoretical Physics 2013年第7期60卷 87-92页

作者： Hazrat ali Ziauddin Iftikhar ahmed Department of Physics University of Malakand Department of Physics COMSATS Institute of Information Technology

We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2005) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field.

关键词： normal and anomalous dispersion Kerr field group index

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comprehensive evaluation and sensitivity analysis of regeneration energy for acid gas removal plant using single and activated-methyl diethanolamine solvents

引用

Chinese Journal of Chemical Engineering 2020年第6期28卷 1684-1693页

作者： Ammar ali Abd Samah Zaki Naji ahmed Barifcani Water Resources Engineering College Al-Qasim Green UniversityBabylonIraq Petroleum Engineering Department Kerbala UniversityKerbalaIraq Chemical Engineering Department Curtin University of TechnologyPerthAustralia.

The absorption of acid gas using reactive amines is among the most widely used types of capturing ***,the absorption process requires intensive energy expenditure majorly in the solvent regeneration *** study simultaneously evaluated the regeneration energy of MDEA and PZ/MDEA solvents in terms of heat of absorption,sensible heat,and vaporization *** Hysys version 8.8 simulation tool is applied to model the full acid gas removal plant for the chemical absorption *** new energy balance technique presents around the absorption and desorption columns to bring a new perspective of energy distribution in the capturing of acid gas *** analysis of regeneration energy and its three contributors is performed at several operation parameters such as absorber and stripper pressures,lean amine circulation rate,solvent concentration,reflux ratio,and CO2 and H2 S *** results show that the heat of absorption of PZ/MDEA system is higher than that for MDEA system for the same operating *** sensible heat is the main contributor in the required regeneration energy of MDEA solvent *** simulation results have been validated against data taken from real plant and *** product specifications of our simulation corroborate with real plant data in an excellent approach;additionally,the profile temperature of the absorber and the stripper columns are in good agreement with *** overall results highlight the direction of the effects of each parameter on the heat of absorption,sensible heat,and vaporization heat.

关键词： Heat of absorption Sensible heat Vaporization heat Regeneration energy Acid gases capturing Piperazine Activated-Methyl diethanolamine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Anti-wear properties evaluation of frictional sliding interfaces in automobile engines lubricated by copper/graphene nanolubricants

引用

Friction 2020年第5期8卷 905-916页

作者： Mohamed Kamal ahmed ali Xianjun HOU Mohamed AAABDELKAREEM Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Automotive and Tractors Engineering Department Faculty of EngineeringMinia UniversityEl-Minia 61111Egypt Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan 430070China

Owing to the significance of improving fuel economy, reducing emissions, and extending the durability of engine components, this study focused on the tribological performance of nano-additives. In this study, copper (Cu) and graphene (Gr) nanomaterials were dispersed in a fully formulated engine oil (5W-30) with different concentrations. The tribological trials were investigated under various speeds and loads, utilizing a reciprocating tribometer to mimic the ring/liner interfaces in the engine. The frictional surface morphologies were com-prehensively analyzed using electron probe X-ray microanalysis (EPMA), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and three dimensional (3D) surface profilometry to explore the mechanisms responsible for improving the tribological performance of the frictional sliding parts in the engine. The tribological test results illustrated that lubrication by nano-additives reduced the wear rate (WR) and friction coefficient (COF) by 25%–30% and 26.5%–32.6%, respectively, as compared with 5W-30. The results showed that this is a promising approach for increasing the durability and lifespan of frictional sliding components and fuel economy in automobile engines.

关键词： engine tribology nanomaterial nanolubricant friction wear tribofilm

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantification of Urban Sprawl for Past-To-Future in Abha City,Saudi Arabia

引用

Computer Modeling in Engineering & Sciences 2021年第11期129卷 755-786页

作者： Saeed AlQadhi Javed Mallick Swapan Talukdar ahmed ali Bindajam ahmed ali A.Shohan Shahfahad Department of Civil Engineering College of EngineeringKing Khalid UniversityAbha61411Saudi Arabia Department of Geography University of Gour BangaMalda732103India Department of Architecture and Planning College of EngineeringKing Khalid UniversityAbha61411Saudi Arabia Department of Geography Faculty of Natural SciencesJamia Millia IslamiaNew Delhi110025India

Given that many cities in Saudi Arabia have been observing rapid urbanization since the 1990s,scarce studies on the spatial pattern of urban expansion in Saudi Arabia have been ***,the present study investigates the evidence of land use and land cover(LULC)dynamics and urban sprawl in Abha City of Saudi Arabia,which has been experiencing rapid urbanization,from the past to the future using novel and sophisticated *** SVM classifier was used in this study to classify the LULC maps for 1990,2000,and *** LULC dynamics between 1990–2000,2000–2018,and 1990–2018 have been analyzed using delta()change and the Markovian transitional probability *** sprawl or urban expansion was modeled using two approaches,such as landscape fragmentation and presence frequency for the first *** future LULC map for 2028 was predicted using the artificial neural network-cellular automata model(ANN-CA).Future LULC was analyzed using landscape fragmentation and frequency *** results of LULC maps showed that urban areas increased by 334.4%between 1990 and *** Delta change rate showed that 16.34%in urban areas has increased since ***,the transitional probability matrix between 1990 and 2018 reported that the built-up area is the largest stable LULC,having an 83.6%transitional probability *** 17.9%,21.8%,12.4%,and 10.5%of agricultural land,scrubland,exposed rocks,and water bodies were transformed into built-up *** sprawl models showed that 139 km^(2)of new urban areas had been set up in 2018,49 and 69 km^(2)in 1990 and ***,in 2018,more than 200%of urban areas were stabilized or became core urban *** future LULC map(2028)showed that the built-up area would be 343.72 km^(2),followed by scrubland(342.98 km^(2))and sparse vegetation(89.96 km^(2)).The new urban area in 2028 would be 169 km^(2).The authorities and planners should focus more on the sustainable development of urban areas;otherwise,it would

关键词： Urban sprawl LULC landscape fragmentation cellular automata SVM frequency approach

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ding w-Flat Modules and Dimensions

引用

Algebra Colloquium 2018年第2期25卷 203-216页

作者： Fuad ali ahmed Almahdi Mohammed Tamekkante Department of Mathematics Faculty of Sciences King Khalid University P. O. Box. 9004 Abha Saudi Arabia Laboratory MACS Faculty of Sciences University Moulay Ismail 5000 P.B. 11201 Zitoune Meknes Morocco

The introduction of w-operation in the class of flat modules has been successful. Let R be a ring. An R-module M is called a w-fiat module if Tor1r（M, N） is GV-torsion for all R-modules N. In this paper, we introduce the w-operation in Gorenstein homological algebra. An R-module M is called Ding w-flat if there exists an exact sequence of projective R-modules ... → P1 → P0 → p0 → p1 → ... such that M Im（P0 → p0） and such that the functor HomR （-,F） leaves the sequence exact whenever F is w-flat. Several well- known classes of rings are characterized in terms of Ding w-flat modules. Some examples are given to show that Ding w-flat modules lie strictly between projective modules and Gorenstein projective modules. The Ding w-flat dimension （of modules and rings） and the existence of Ding w-flat precovers are also studied.

关键词： w-fiat module and dimension Gorenstein projective module and dimension,strongly Gorenstein flat module

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Multi-Objective Vendor Selection Problem of Supply Chain Management Under Fuzzy Environment

引用

Journal of the Operations Research Society of China 2021年第1期9卷 33-62页

作者： Srikant Gupta Irfan ali Aquil ahmed Department of Statistics and Operations Research Aligarh Muslim UniversityAligarhUPIndia

Survival of a company in today's competitive business environment depends mainly on its supply *** adequate supply chain gives a competitive edge to a ***,which is the initial stage of a supply chain,can be made efficient by making an appropriate selection of *** vendor selection results not only in reduced purchasing costs,decreased production lead time,increased customer satisfaction but also in improved corporate *** general,the vendor selection problem is a multi-objective decision-making problem that involves some quantitative and qualitative ***,we have considered a multi-objective ven-dor selection problem(MOV SP)with three multiple objective goals:minimization of net ordering price,minimization of rejected units and minimization of late delivered *** most of the cases,information about the price of a unit,percentage of rejected units,percentage of late delivered units,vendor rating value and vendor quota flexibil-ity may not be known precisely due to some *** this paper,imprecision in input information is handled by the concept of a simulation technique,where the parameter follows the uniform ***,stochastic,a-cut and ranking function approaches are used to get the crisp value of the simulated data *** four differ-ent algorithms,namely-fuzzy programming,goal programming,lexicographic goal programming and D1-distance algorithm,have been used for solving the *** last,three different types of simulated data sets have been used to illustrate the work.

关键词： Vendor selection problem Trapezoidal fuzzy number α-Cut and ranking function Fuzzy programming Goal programming Lexicographic goal programming

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Survey and technological analysis of laser and its defense applications

引用

Defence Technology（防务技术） 2021年第2期17卷 583-592页

作者： Syed Affan ahmed Mujahid Mohsin Syed Muhammad Zubair ali Department of Avionics Engineering-College of Aeronautical Engineering(CAE) National University of Sciences and Technology(NUST)RisalpurKPKPakistan

The laser technology has made remarkable progress over the past couple of *** is being widely employed in diverse domains,such as holography,space sciences,spectroscopy,medical sciences,micro and power electronics,industrial engineering,and most distinctively,as directed energy military *** to their active transmissions,laser systems are similar to microwave radars to some extent;however,unlike conventional radars,the laser operates at very high frequencies thus making it a potent enabler of narrow-beam and high energy aerial deployments,both in offensive and defensive *** modern avionics systems,laser target indicators and beam riders are the most common devices that are used to direct the Laser Guided Weapons(LGW)accurately to the ground ***,compact size and outstanding angular resolution of laser-based systems motivate their use for drones and unmanned aerial ***,the narrow-beam divergence of laser emissions offers a low probability of intercept,making it a suitable contender for secure transmissions and safety-critical ***,the developments in space sciences and laser technology have given synergistic potential outcomes to use laser systems in space *** paper comprehensively reviews laser applications and projects for strategic defense actions on the ground or in ***,a detailed analysis has been done on recent advancements of the laser technology for target indicators and *** also reviews the advancements in the field of laser communications for surveillance,its earlier state of the art,and ongoing scientific research and advancements in the domain of high energy directed laser weapons that have revolutionized the evolving military *** offering a comprehensive taxonomy,the paper also critically analyzes some of the recent contributions in the associated domains.

关键词： Laser systems Laser military applications Directed energy weapons Non-lethal weapons Laser military projects Survey Taxonomy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：