检索结果-南通市图书馆

Heat transfer analysis in particle-laden flows using the immersed boundary method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 394-403页

作者： Ali Abbas Zaidi department of mechanical engineering University of Manitoba75A Chancellors CircleWinnipegR3T 5V6Canada

This paper investigates an efficient immersed boundary method(IBM)for multiple-core CPU machines with local grid refinement for the calculation of heat transfer between fluids and finite-sized *** fluid momentum equations are solved by using the fractional step method,while the energy equation is solved by employing the second-order Adams-Bashforth *** efficient load balancing between the CPU cores,the coupling between particles and fluid is obtained by applying the body force in the fluid equations,which depends on the solid volume fraction of particles contained in each grid cell,and then by linearly interpolating the particle temperature and velocity on the fluid grid cell(in place of the delta function commonly used in literature).Several test cases from the literature are studied,and good agreement is observed between the simulation results and the ***,a scaling study on multiple core machines is performed,demonstrating the proposed IBM's capabilities for a significant reduction in processing time.

关键词： Heat transfer Immersed boundary method Particle resolved direct numerical simulations Fluid solid interactions

On dry machining of AZ31B magnesium alloy using textured cutting tool inserts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1608-1618页

作者： Shailendra Pawanr Kapil Gupta department of mechanical and industrial engineering Technology University of JohannesburgDoornfontein CampusJohannesburg 2028 South Africa

Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and *** undergo extensive cutting or machining while making products out of *** cutting,a sustainable machining method,causes more friction and adhesion at the tool-chip *** of the promising solutions to this problem is cutting tool surface texturing,which can reduce tool wear and friction in dry cutting and improve machining *** paper aims to investigate the impact of dimple textures(made on the flank face of cutting inserts)on tool wear and chip morphology in the dry machining of AZ31B magnesium *** results show that the cutting speed was the most significant factor affecting tool flank wear,followed by feed rate and cutting *** tool wear mechanism was examined using scanning electron microscope(SEM)images and energy dispersive X-ray spectroscopy(EDS)analysis reports,which showed that at low cutting speed,the main wear mechanism was abrasion,while at high speed,it was *** chips are discontinuous at low cutting speeds,while continuous at high cutting *** dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.

关键词： Magnesium alloy Dry machining Textured tools Flank wear Sustainability

Breakdown of effective medium theory:A study of photonic spin Hall effect in deep-subwavelength all-dielectric multilayers

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 173-174页

作者： Yongmin Liu department of mechanical and industrial engineering Northeastern UniversityBoston 02115USA department of Electrical and Computer engineering Northeastern UniversityBoston 02115USA

Effective medium theory(EMT)has been widely applied in material science,electromagnetics and photonics to determine the effective material properties for inhomogeneous composites comprising subwavelength *** versatility of this foundational approach has been established through its application in classical Maxwell-Garnet models,which encompass relatively simple structures。

关键词： composites theory dielectric

同方期刊数据库

Broadband angular spectrum analog processors based on all-dielectric metasurfaces

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 188-190页

作者： Lin Deng Yongmin Liu department of Electrical and Computer engineering Northeastern UniversityBoston 02115USA department of mechanical and industrial engineering Northeastern UniversityBoston 02115USA

Digital signal processors are extensively used to execute mathematical operations and advanced computational tasks on digital ***,they suffer from several inherent limitations,including low speed,high energy consumption,and large memory requirements,because of the hardware bottleneck and the imperative conversion between digital and analogue signals.

关键词： dielectric spectrum hardware

同方期刊数据库

Reconfigurable optical neural networks with Plug-and-Play metasurfaces

在线全文

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第7期7卷 1-3页

作者： Yongmin Liu Yuxiao Li department of mechanical and industrial engineering Northeastern UniversityBostonMassachusetts 02115USA department of Electrical and Computer engineering Northeastern UniversityBostonMassachusetts 02115USA

In a very recent study,*** Huang and co-workers proposed and demonstrated reconfigurable optical neural networks based on cascaded *** fixing one metasurface and switching the other pluggable metasurfaces,the neural networks,which operate at near-infrared wavelengths,can perform distinct recognition tasks for handwritten digits and fashion *** innovative device opens up an avenue for all-optical,high-speed,low-power,and multifunctional artificial intelligence systems.

关键词： surfaces networks neural

Accurate Distinction of Weak and Strong AC Grids for Emerging Hierarchical-Infeed LCC-UHVDC Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第2期10卷 772-777页

作者： Hao Xiao Xianzhong Duan Yi Zhang department of Electrical and Computer engineering University of ManitobaWinnipeg R3T 2N2ManitobaCanada State Key Laboratory of Advanced Electromagnetic engineering and Technology Hubei Electric Power Security and High Efficiency Key LaboratorySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina RTDS Technologies Inc. Winnipeg R3T 2E1ManitobaCanada

Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.

关键词： Hierarchical-Infeedinteractive effective short-circuit ratio hierarchical-infeed LCC-UHVDC systems inter-inverter interactions strong AC grids weak AC grids

Gradient layered MXene/Fe3O4@CNTs/TOCNF ultrathin nanocomposite paper exhibiting effective electromagnetic shielding and multifunctionality

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8233-8242页

作者： Zhengkun Ma Jingzong He Shilin Liu Xiaoxuan Qie Meiheng Gan Ruonan Cheng Qilin Wu Malcolm Xing State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China College of Chemistry and Chemical engineering Donghua UniversityShanghai 201620China department of mechanical engineering University of ManitobaWinnipegMB R3T 2N2Canada

As wearable electronic devices are rapidly developing,there is an urgent need for lightweight,flexible,and ultrathin multifunctional electromagnetic interference(EMI)shielding ***,the flexible ultrathin paper that combines efficient shielding and multifunctional integration remains a considerable ***,a novel MXene/Fe_(3)O_(4)@CNTs/TOCNF(MCT,MXene=transition metal carbide/carbonitride,CNTs=carbon nanotubes,TOCNF=TEMPO-oxidized cellulose nanofiber,TEMPO=2,2,6,6-tetramethylpiperidine-1-oxyl radical)nanocomposite paper with a multilayer electromagnetic gradient structure and electromagnetic dual losses was successfully prepared by a simple filtration *** from effective gradient design and adjusting the proportion of TOCNF,the composite paper(only 18μm)exhibits outstanding shielding effectiveness(SE)of 66 dB in the X-band,ultrahigh thickness-specific SE and surface-specific SE values of 3300 dB·mm-1 and 31,428 dB·cm^(2)·g^(-1)***,dehydroxylation treatment improves MCT paper's hydrophobicity,environmental stability,and mechanical strength,expanding its range of ***,the highly efficient Joule heating properties and hydrophobicity provide MCT additional de-icing *** also simulated the electromagnetic shielding effects of MCT composite paper,which was applied in *** study documents an innovative and intriguing material combination,providing a simple and effective manufacturing strategy for developing EMI shielding *** paper is highly suitable for outdoor portable or wearable electronic devices and has significant application potential in humid/severe cold environments.

关键词： cellulose fiber thin papers nanocomposites electromagnetic interference(EMI)shielding

Cryogenic and conventional milling of AZ91 magnesium alloy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第6期12卷 2503-2519页

作者： Vikas Marakini Srinivasa Pai P Gururaj Bolar Bhaskara P Achar department of mechanical engineering Nitte(Deemed to be University)NMAM Institute of Technology(NMAMIT)Nitte 574110India department of mechanical and industrial engineering Manipal Institute of TechnologyManipal Academy of Higher EducationManipal 576104India

Use of magnesium is the need of the hour due to its low density as well as its high strength-to-weight and stiffness-to-weight ratio *** study focuses on the effectiveness of liquid nitrogen(LN_(2))assisted cryogenic machining on the surface integrity(SI)characteristics of AZ91 magnesium *** milling using uncoated carbide inserts have been performed under liquid nitrogen(LN_(2))assisted cryogenic condition and compared with conventional(dry)*** are performed using machining parameters in terms of cutting speeds of 325,475,625 m/min,feed rates of 0.05,0.1,0.15 mm/teeth and depth of cuts of 0.5,1,1.5 mm *** significant surface integrity characteristics such as surface roughness,microhardness,microstructure,and residual stresses have been *** of SI characteristics with respect to milling parameters have been identified using statistical technique such as ANOVA and signal-to-noise(S/N)ratio ***,the multi criteria decision making(MCDM)techniques such as additive ratio assessment method(ARAS)and complex proportional assessment(COPRAS)have been utilized to identify the optimal conditions for milling AZ91 magnesium alloy under both dry and cryogenic *** of LN_(2)during machining,resulted in reduction in machining temperature by upto 29%with a temperature drop from 251.2℃under dry condition to 178.5℃in cryogenic *** showed the advantage of performing cryogenic milling in improving the surface integrity to a significant *** machining considerably minimized the roughness by upto 28%and maximised the microhardness by upto 23%,when compared to dry *** speed has caused significant impact on surface roughness(95.33%-dry,92.92%-cryogenic)and surface microhardness(80.33%-dry,82.15%-cryogenic).Due to the reduction in machining temperature,cryogenic condition resulted in compressive residual stresses(maximumσ║=-113 MPa)on the alloy *** indicate no

关键词： Magnesium alloy Cryogenic machining Roughness Microhardness Microstructure Residual stress Multi criteria decision making

Chaotic Aquila Optimization Algorithm for Solving Phase Equilibrium Problems and Parameter Estimation of Semi-empirical Models

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic engineering 2024年第1期21卷 486-526页

作者： Oguz Emrah Turgut Mert Sinan Turgut Erhan Kırtepe department of industrial engineering Faculty of Engineering and ArchitectureIzmir Bakircay UniversityMenemenizmirTurkey department of mechanical engineering Faculty of EngineeringEge UniversityBornovaizmirTurkey department of Motor Vehicles and Transportation Technologies Sirnak UniversitySirnakTurkey

This research study aims to enhance the optimization performance of a newly emerged Aquila Optimization algorithm by incorporating chaotic sequences rather than using uniformly generated Gaussian random *** work employs 25 different chaotic maps under the framework of Aquila *** considers the ten best chaotic variants for performance evaluation on multidimensional test functions composed of unimodal and multimodal problems,which have yet to be studied in past literature *** was found that Ikeda chaotic map enhanced Aquila Optimization algorithm yields the best predictions and becomes the leading method in most of the *** test the effectivity of this chaotic variant on real-world optimization problems,it is employed on two constrained engineering design problems,and its effectiveness has been ***,phase equilibrium and semi-empirical parameter estimation problems have been solved by the proposed method,and respective solutions have been compared with those obtained from state-of-art *** is observed that CH01 can successfully cope with the restrictive nonlinearities and nonconvexities of parameter estimation and phase equilibrium problems,showing the capabilities of yielding minimum prediction error values of no more than 0.05 compared to the remaining algorithms utilized in the performance benchmarking process.

关键词： Aquila optimization algorithm Chaotic maps Parameter estimation Phase equilibrium Unconstrained optimization