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Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 373-388页

作者： M.rahman M.TURKYILMAZOGLU Z.MUSHTAQ Department of Mathematics Mirpur University of Science and TechnologyMirpur 10250Pakistan Department of Mathematics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the same volume of a *** leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity *** system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c MATLAB *** outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower *** the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom *** ranges of various parameters taken into account are Pr=6.2,Re=2,M=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number

Efficient Algorithm for Prolonging Network Lifetime of Wireless Sensor Networks

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Tsinghua Science and Technology 2011年第6期16卷 561-568页

作者： Md Nafees rahman M A Matin Department of Electrical Engineering and Computer Science North South University

One of the fundamental design challenges in designing a Wireless Sensor Network （WSN） is to maximize the network lifetime, as each sensor node of the network is equipped with a limited power battery. To overcome this challenge, different methods were developed in the last few years using such techniques as network protocols, data fusion algorithms using low power, energy efficient routing, and locating optimal sink position. This paper focuses on finding the optimal sink position. Relay nodes are introduced in conjunction with the sensor nodes to mitigate network geometric deficiencies since in most other approaches the sensor nodes close to the sink become heavily involved in data forwarding and, thus, their batteries are quickly depleted. A Particle Swarm Optimization （PSO） based algorithm is used to locate the optimal sink position with respect to those relay nodes to make the network more energy efficient. The relay nodes communicate with the sink instead of the sensor nodes. Tests show that this approach can save at least 40% of the energy and prolong the network lifetime.

关键词： wireless sensor network lifetime sensor node relay node particle swarm optimization sink

A critical review of the emerging research on the detection and assessment of microplastics pollution in the coastal,marine,and urban Bangladesh

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Frontiers of Environmental Science & Engineering 2022年第10期16卷 39-52页

作者： Zaki Alam Pushan Ehsanur rahman Nafisa Islam Nirupam Aich Department of Chemical Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Department of Civil Environmentaland Geo-EngineeringUniversity of Minnesota-Twin CitiesMinneapolisMN 55455USA Department of Civil Structural and Environmental EngineeringUniversity at BuffaloThe State University of New YorkBuffaloNY 14260USA

The research on the extent and effects of microplastics pollution in the Global South is only getting *** is a South Asian country with one of the fastest growing economies in the world,however,such exponential economic growth has also increased the pollution threats to its natural and urban *** this paper,we reviewed the recent primary research on the assessment of the extent of microplastics pollution in *** online databases,we developed a compilation of emergingresearch articles that detected and quantified microplastics in different coastal,marine,and urban environments in *** of the studies focused on the coastal environment(e.g.,beach sediment)and marine fish,while limited data were available for the urban *** also discussed the relationship of the type of anthropogenic activities with the observed microplastic *** Cox's Bazar sea beach in south-east Bangladesh experienced microplastics pollution due to tourism activities,while fishing and other anthropogenic activities led to microplastics pollution in the Bay of *** microplastics larger than 1 mm were prevalent in the beach sediments,smaller microplastics with size below 0.5 mm were prevalent in marine fish ***,the differences m microplastic abundance,size,shape,color,and polymer type found were depended on the sampling sites and relevant anthropogenic *** is imperative to identify majorsources of microplastics pollution in both natural and urban environment,determine potential environmental and human health effects,and develop mitigating and prevention strategies for reducing microplastics pollution.

关键词： Plastic pollution Waste management Global south Sustainability Marine pollution

Experimental investigation on the stability of bride girder against tsunami forces

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Science China(Technological Sciences) 2014年第10期57卷 2028-2036页

作者： rahman Sadia AKIB Shatirah SHIRAZI S M Department of Civil Engineering Faculty of Engineering University of Malaya Institute of Environmental and Water Resources Management (IPASA) Faculty of EngineeringUniversiti Teknologi Malaysia

Bridges are the most useful part in the transportation *** disruption of the bridge structures may hamper the whole transportation *** the last recent tsunamis,numerous number of bridges were structurally damaged by the tsunami *** of proper provisions of tsunami forces in the design guidelines also contributes to the augmentations of the damage ***,proper evaluation of the tsunami forces on the bridge girder should be introduced in the design *** this study,laboratory experiments were carried out to reveal the damage mechanism of the bridge girder by assessing the exerted tsunami *** broken and unbroken waves were considered for the *** results showed that measured forces were larger for broken waves than those of unbroken *** force of the broken waves was 4.59 times as large as the hydrostatic ***,waves reached the peak value more rapidly for larger wave heights than those of smaller ***,a girder that is placed at a higher position is much vulnerable to tsunami hazard.

关键词： bridge force girder tsunami wave forms wave height

NANOSCALE CUTTING OF MONOCRYSTALLINE SILICON USING MOLECULAR DYNAMICS SIMULATION

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Chinese Journal of Mechanical Engineering 2007年第5期20卷 8-11页

作者： LI Xiaoping CAI Minbo rahman Mustafizur Department of Mechanical Engineenng National University of Singapore Kent Ridge 119260 Singapore

It has been found that the brittle material, monocrystalline silicon, can be machined in ductile mode in nanoscale cutting when the tool cutting edge radius is reduced to nanoscale and the undeformed chip thickness is smaller than the tool edge radius. In order to better understand the mechanism of ductile mode cutting of silicon, the molecular dynamics （MD） method is employed to simulate the nanoscale cutting of monocrystalline silicon. The simulated variation of the cutting forces with the tool cutting edge radius is compared with the cutting force results from experimental cutting tests and they show a good agreement. The results also indicate that there is silicon phase transformation from monocrystalline to amorphous in the chip formation zone that can be used to explain the cause of ductile mode cutting. Moreover, from the simulated stress results, the two necessary conditions of ductile mode cutting, the tool cutting edge radius are reduced to nanoscale and the undeformed chip thickness should be smaller than the tool cutting edge radius, have been explained.

关键词： Ductile mode cutting Molecular dynamics Phase transformation Force Stress

First-principles study of electronic structure and magnetic properties of Sr_(3)Fe_(2)O_(5) oxide

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Chinese Physics B 2021年第11期30卷 515-518页

作者： Mavlanjan rahman Jiuyang He School of Physics and Electronic Engineering Xinjiang Normal UniversityUrumqi 830054China

We investigate the electronic structure and magnetic properties of layered compound Sr_(3)Fe_(2)O_(5) based on firstprinciples calculations in the framework of density functional theory with GGA+U *** high pressure,the ladder-type layered structure of Sr_(3)Fe_(2)O_(5) is transformed into the infinite layered structure accompanied by a transition from G-type anti-ferromagnetic(AFM)insulator to ferromagnetic(FM)metal and a spin transition from S=2 to S=*** reproduce these transformations in our calculations and give a clear physical interpretation.

关键词： Sr3Fe2O5 first-principles calculation electronic structure magnetism

An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives

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Chinese Chemical Letters 2010年第10期21卷 1171-1174页

作者： rahman Hosseinzadeh Yaghoub Sarrafi Nora Aghili Department of Organic Chemistry Faculty of ChemistryUniversity of Mazandaran

A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in... 详细信息

关键词： Unsymmetrical ureas Phenylurea Amines Uncatalyzed reaction

Face Mask and Social Distance Monitoring via Computer Vision and Deployable System Architecture

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Intelligent Automation & Soft Computing 2023年第3期35卷 3641-3658页

作者： Meherab Mamun Ratul Kazi Ayesha rahman Javeria Fazal Naimur rahman Abanto Riasat Khan Department of Electrical and Computer Engineering North South UniversityDhakaBangladesh

The coronavirus(COVID-19)is a lethal virus causing a rapidly infec-tious disease throughout the *** awareness,taking preventive mea-sures,imposing strict restrictions on public gatherings,wearing facial masks,and maintaining safe social distancing have become crucial factors in keeping the virus at *** though the world has spent a whole year preventing and curing the disease caused by the COVID-19 virus,the statistics show that the virus can cause an outbreak at any time on a large scale if thorough preventive measures are not maintained ***ﬁght the spread of this virus,technologically developed systems have become very ***,the implementation of an automatic,robust,continuous,and lightweight monitoring system that can be efﬁciently deployed on an embedded device still has not become prevalent in the mass *** paper aims to develop an automatic system to simul-taneously detect social distance and face mask violation in real-time that has been deployed in an embedded system.A modiﬁed version of a convolutional neural network,the ResNet50 model,has been utilized to identify masked faces in *** Only Look Once(YOLOv3)approach is applied for object detection and the DeepSORT technique is used to measure the social *** efﬁciency of the proposed model is tested on real-time video sequences taken from a video streaming source from an embedded system,Jetson Nano edge computing device,and smartphones,Android and iOS *** results show that the implemented model can efﬁciently detect facial masks and social distance viola-tions with acceptable accuracy and precision scores.

关键词： Artiﬁcial intelligence COVID-19 deep learning technique face mask detection social distance monitor you only look once

Driver Intent Prediction and Collision Avoidance With Barrier Functions

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 365-375页

作者： Yousaf rahman Abhishek Sharma Mrdjan Jankovic Mario Santillo Michael Hafner the Ford Motor Company DearbornMichigan 48121 USA IEEE

For autonomous vehicles and driver assist systems,path planning and collision avoidance algorithms benefit from accurate predictions of future location of other vehicles and intent of their *** the literature,the algorithms that provide driver intent belong to two categories:those that use physics based models with some type of filtering,and machine learning based *** this paper we employ barrier functions(BF)to decide driver *** are typically used to prove safety by establishing forward invariance of an admissible ***,we decide if the“target”vehicle is violating one or more possibly fictitious(i.e.,non-physical)barrier constraints determined based on the context provided by the road *** algorithm has a very small computational footprint and better false positive and negative rates than some of the *** predicted intent is then used by a control barrier function(CBF)based collision avoidance system to prevent unnecessary interventions,for either an autonomous or human-driven vehicle.

关键词： Driver Intent Prediction and Collision Avoidance With Barrier Functions Intent