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Effectiveness of radiative heat flux in MHD flow of Jeffrey-nanofluid subject to Brownian and thermophoresis diffusions

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Journal of Hydrodynamics 2019年第2期31卷 421-427页

作者： muhammad Ijaz Khan Tasawar Hayat muhammad waqas Ahmed Alsaedi muhammad Imran Khan Department of Mathematics Quaid-I-Azam UniversityIslamabadPakistan Nonlinear Analysis and Applied Mathematics(NAAM)Research Group Department of MathematicsFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia Heriot Watt University Edinburgh CampusEdinburghUK

Our interest here in this investigation is to explore the thermophoresis and Brownian motion characteristics in flow induced by stretched *** conducted Jeffrey material formulates the flow *** forms of stretching and free stream velocities are *** radiation and convective heating processes describe the phenomenon of heat *** controls of nanoparticles are considered on the *** compatible transformations produce the strong nonlinear differential *** problems are computed analytically utilizing *** nee domain is detennined and major results are concluded for different parameters *** transfer rate and drag force are also explained for various physical *** analysis reveals that heat transfer rate augments via larger radiation parameter and Biot *** larger Brownian motion and thermophoresis parameters have opposite characteristics on concentration field.

关键词： Jeffrey nanomaterial non-linear radiative heat flux convective boundary conditions.Brownian and thermophoresis diffusions

Design optimization of composite egg-shaped submersible pressure hull for minimum buoyancy factor

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Defence Technology（防务技术） 2021年第6期17卷 1817-1832页

作者： muhammad Imran Dongyan Shi Lili Tong Hafiz muhammad waqas Muqeem Uddin College of Mechanical and Electrical Engineering Harbin Engineering University Harbin150001China College of Aerospace and Civil Engineering Harbin Engineering University Harbin150001China Pakhtunkhwa Energy Development Organization(PEDO) Khyber PakhtunkhwaPakistan

This paper describes a design optimization study of the composite egg-shaped submersible pressure hull employing optimization and finite element analysis(FEA)tools as a first attempt to provide an optimized design of the composite egg-shaped pressure hull for manufacturing or further investigations.A total of 15 optimal designs for the composite egg-shaped pressure hull under hydrostatic pressure are obtained in terms of fibers’angles and the number of layers for 5 lay-up arrangements and 3 unidirectional(UD)composite *** optimization process is performed utilizing a genetic algorithm and FEA in *** minimization of the buoyancy factor eB:FT is selected as the objective for the optimization under constraints on both material failure and buckling *** buckling analysis is conducted for one optimal design considering both geometric nonlinearity and imperfections.A sensitivity study is also conducted to further investigate the influence of the design variables on the optimal design of the egg-shaped pressure hull.

关键词： Composite egg-shaped pressure hull Design optimization Buoyancy factor Material failure Buckling instability

Evaluation of microstructure and mechanical properties of squeeze overcast Al7075-Cu composite joints

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China Foundry 2023年第1期20卷 29-39页

作者： muhammad waqas Hanif Ahmad Wasim muhammad Sajid Salman Hussain muhammad Jawad Mirza Jahanzaib Department of Industrial Engineering University of Engineering and Technology TaxilaPunjabPakistan

Al7075-Cu composite joints were prepared by the squeeze overcast *** effects of melt temperature,die temperature,and squeeze pressure on hardness and ultimate tensile strength(UTS)of squeeze overcast Al7075-Cu composite joints were *** experimental results depict that squeeze pressure is the most significant process parameter affecting the hardness and *** optimal values of UTS(48 MPa)and hardness(76 HRB)are achieved at a melt temperature of 800℃,a die temperature of 250℃,and a squeeze pressure of 90 *** electron microscopy(SEM)shows that fractured surfaces show flatfaced morphology at the optimal experimental ***-dispersive spectroscopy(EDS)analysis depicts that the atomic weight percentage of Zn decreases with an increase in melt temperature and squeeze *** optimal mechanical properties of the Al7075-Cu overcast joint were achieved at the Al2Cu eutectic phase due to the large number of copper atoms that dispersed into the aluminum melt during the solidification process and the formation of strong intermetallic *** relational analysis integrated with the Taguchi method was used to develop an optimal set of control variables for multi-response parametric *** tests were performed to validate the effectiveness of the employed *** manufacturing of squeeze overcast Al7075-Cu composite joints at optimal process parameters delivers a great indication to acknowledge a new method for foundry practitioners to manufacture materials with superior mechanical properties.

关键词： squeeze overcast joints Al7075-Cu composite joints mechanical properties gray relational analysis Taguchi method

Fe-Promoted Copper Oxide Thin-Film Catalysts for the Catalytic Reduction of N_(2)O in the Presence of Methane

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Journal of Thermal Science 2023年第2期32卷 531-541页

作者： muhammad waqas WU Lingnan EI KASMI Achraf muhammad Ammar TIAN Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Mechanical Engineering College of Engineering and TechnologyUniversity of SargodhaSargodha 40100Pakistan Laboratory LSIA UAE/U02ENSAHNational School of Applied Sciences of Al HoceimaAbdelmalek Essaadi UniversityAl Hoceima 32003Morocco Department of Chemical Engineering Technology Government College UniversityFaisalabad 38000Pakistan

Thin-film catalysts are recently recognized as promising catalysts due to their reduced amount of materials and good catalytic activity,leading to low-cost and high-efficiency catalysts.A series of CuFeO_(x)thin-film catalysts were prepared with different Fe contents using a one-step method as well as tested for the catalytic reduction of nitrous oxide(N_(2)O)in the presence of CH_(4)at a high GH SV of 185000 mL/(g·h).The increase of iron strongly affects the dispersion and leads to the creation of a less-active segregated Fe_(2)O_(3)phase,which was confirmed by XRD,EDX,and XPS *** results show that the synergistic properties between Cu and Fe,which affect the CuFeOxfilm catalysts in many aspects,such as the hollow-like texture,specific surface area,nano-crystallite size,the surface contents of Cu^(+),Fe^(3+),and oxygen species,the reductive strength and the strong active sites on the *** DFT calculations,the adsorption and decomposition energy profiles of N_(2)O on the CuFeO_(2)(012)surface model were *** surface Fe-site and hollow-site are active for N_(2)O decomposition,and the decomposition energy barriers on the Fe-site and the hollow-site are 1.02 eV and 1.25 eV respectively at 0 *** strategy adopted here to tailor the activity through low-doping Fe-oxide catalysts could establish a promising way to improve the catalytic reduction of N_(2)O with CH_(4).

关键词： catalytic reduction thin-film catalysts doping strategy density functional theory calculations N_(2)O decomposition

Transmit Power Optimization for Relay-Aided Multi-Carrier D2D Communication

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Tsinghua Science and Technology 2018年第1期23卷 65-74页

作者： muhammad waqas Guftaar Ahmad Sardar Sidhu Tayyaba Jabeen muhammad Afaq Ahmad muhammad Awais Javed Department of Electrical Engineering COMSATS Institute of Information Technology (CIIT) Islamabad 44000 Pakistan Transmission Department Pakistan Telecommunication Company Limited (PTCL) Islamabad 44000 Pakistan

In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing （OFDM）-based relay-enhanced device-to-device （D2D） communication. In a single cell transmission scenario, dual- hop communication is assumed in which each D2D user re-uses the spectrum of just one Cellular User （CU）. In this work, we formulate a joint optimization scheme under a Decode-and-Forward （DF） relaying protocol to maximize the sum throughput of D2D and cellular networks via power allocation over different sub-carriers. The problem is thus transformed into a standard convex optimization, subject to individual power constraints at different transmitting nodes. We exploit the duality theory to decompose the problem into several sub-problems and use Karush-Kuhn- Tucker （KKT） conditions to solve each sub-problem. We provide simulation results to validate the performance of our proposed scheme.

关键词： device-to-device communication Orthogonal Frequency Division Multiplexing (OFDM) Decode-and-Forward (DF) relay transmission power optimization

Cu-Promoted Cobalt Oxide Film Catalyst for Efficient Gas Emissions Abatement

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Journal of Thermal Science 2019年第2期28卷 225-231页

作者： EL KASMI Achraf waqas muhammad MOUNTAPMBEME KOUTOU Patrick TIAN Zhenyu Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences National Advanced School Engineering of Maroua University of Maroua

Thin film catalysts have been recently reported as promising catalysts owing to their good catalytic activity and reduced material amount, leading to low-cost efficient catalysts for gaseous emissions control. Here, we report the slight loading of Cu in cobalt spinel using a one-step pulsed-spray evaporation chemical vapor deposition(PSE-CVD) synthesis technique for efficient short-chain volatile organic compounds(VOCs) emissions treatment. Crystalline structure and morphology analyses revealed nano-crystallite sizes and open-like morphology. The catalytic performance was evaluated through the complete oxidation of C_3H_6, as a short-chain representative model of VOCs, at a high gas hourly space velocity(GHSV). Very good activity was obtained towards the complete abatement of C_3H_6 at low temperature and no carbon monoxide(CO) was formed during the oxidation process. Slightly-promoted Co_3O_4 catalyst with Cu introduction resulted in high catalytic activity comparing to the performance of the catalysts in the literature, due to the high dispersion of Cu and high active surface oxygen amount. Moreover, to evaluate the capability of the used catalysts under near realistic reaction conditions, CO_2 effect on the catalytic activity was performed and the catalyst exhibited very good results. Thus, the adopted slightly-doping strategy to tailor a high active catalyst at low temperature could establish a very promising route to strongly enhance the activity of such other catalysts towards gas emissions abatement at low temperature.

关键词： low Cu-doping PSE-CVD technique thin film catalysts complete catalytic oxidation VOCs

Multi-objective design optimization of composite submerged cylindrical pressure hull for minimum buoyancy and maximum buckling load capacity

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Defence Technology（防务技术） 2021年第4期17卷 1190-1206页

作者： muhammad Imran Dong-yan Shi Li-li Tong Ahsan Elahi Hafiz muhammad waqas Muqeem Uddin College of Mechanical and Electrical Engineering Harbin Engineering University Harbin 150001China College of Aerospace and Civil Engineering Harbin Engineering University Harbin 150001China Pakhtunkhwa Energy Development Organization(PEDO) Khyber PakhtunkhwaPakistan

This paper presents the design optimization of composite submersible cylindrical pressure hull subjected to 3 MPa hydrostatic *** design optimization study is conducted for cross-ply layups[0_(s)/90_(t)/0_(u)],[0_(s)/90_(t)/0_(u)]s,[0_(s)/90_(t)]s and[90_(s)/0_(t)]s considering three uni-directional composites,***/Epoxy,Glass/Epoxy,and Boron/*** optimization study is performed by coupling a Multi-Objective Genetic Algorithm(MOGA)and Analytical *** the buoyancy factor and maximizing the buckling load factor are considered as the objectives of the optimization *** objectives of the optimization are achieved under constraints on the Tsai-Wu,Tsai-Hill and Maximum Stress composite failure criteria and on buckling load *** verify the optimization approach,optimization of one particular layup configuration is also conducted in ANSYS with the same objectives and constraints.

关键词： Multi-objective genetic algorithm Optimization Composite submersible pressure hull Thin shell Material failure Shell buckling

The Impact of Domain Name Server(DNS)over Hypertext Transfer Protocol Secure(HTTPS)on Cyber Security:Limitations,Challenges,and Detection Techniques

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Computers, Materials & Continua 2024年第9期80卷 4513-4542页

作者： muhammad Dawood Shanshan Tu Chuangbai Xiao muhammad Haris Hisham Alasmary muhammad waqas Sadaqat Ur Rehman Faculty of Information Technology Beijing University of TechnologyBeijing100124China National Center of Robotics and Automation University of Engineering and TechnologyPeshawar25000Pakistan Department of Computer Science College of Computer ScienceKing Khalid UniversityAbha61421Saudi Arabia School of Computing and Engineering Sciences Faculty of Engineering and ScienceUniversity of GreenwichLondonSE109LSUnited Kingdom School of Engineering Edith Cowan UniversityPerthWA 6027Australia School of Computer Science and Engineering University of SalfordManchesterM54BRUnited Kingdom

The DNS over HTTPS(Hypertext Transfer Protocol Secure)(DoH)is a new technology that encrypts DNS traffic,enhancing the privacy and security of ***,the adoption of DoH is still facing several research challenges,such as ensuring security,compatibility,standardization,performance,privacy,and increasing user *** significantly impacts network security,including better end-user privacy and security,challenges for network security professionals,increasing usage of encrypted malware communication,and difficulty adapting DNS-based security ***,it is important to understand the impact of DoH on network security and develop newprivacy-preserving techniques to allowthe analysis of DoH traffic without compromising user *** paper provides an in-depth analysis of the effects of DoH on *** discuss various techniques for detecting DoH tunneling and identify essential research challenges that need to be addressed in future security ***,this paper highlights the need for continued research and development to ensure the effectiveness of DoH as a tool for improving privacy and security.

关键词： DNS DNS over HTTPS cybersecurity machine learning

DDoS Detection in SDN using Machine Learning Techniques

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Computers, Materials & Continua 2022年第4期71卷 771-789页

作者： muhammad waqas Nadeem Hock Guan Goh Vasaki Ponnusamy Yichiet Aun Faculty of Information and Communication Technology(FICT) Universiti Tunku Abdul Rahman(UTAR)Jalan UniversitiBandar Barat31900 KamparPerakMalaysia

Software-defined network(SDN)becomes a new revolutionary paradigm in networks because it provides more control and network operation over a network *** SDN controller is considered as the operating system of the SDN based network infrastructure,and it is responsible for executing the different network applications and maintaining the network services and *** all its tremendous capabilities,the SDN face many security issues due to the complexity of the SDN *** denial of services(DDoS)is a common attack on SDN due to its centralized architecture,especially at the control layer of the SDN that has a network-wide *** learning is now widely used for fast detection of these *** this paper,some important feature selection methods for machine learning on DDoS detection are *** selection of optimal features reflects the classification accuracy of the machine learning techniques and the performance of the SDN controller.A comparative analysis of feature selection and machine learning classifiers is also derived to detect SDN *** experimental results show that the Random forest(RF)classifier trains the more accurate model with 99.97%accuracy using features subset by the Recursive feature elimination(RFE)method.

关键词： Machine learning software-defined network distributed denial of services feature selection protection artificial neural network decision trees naïve bayes security