检索结果-南通市图书馆

IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 360-366页

作者： m.d.S.Aliyu department of Electrical Engineering King Faisal University Al-Ahsa 31982 Saudi Arabia IEEE

In this paper, we propose an iterative relaxation method for solving the Hamilton-Jacobi-Bellman-Isaacs equation(HJBIE) arising in deterministic optimal control of affine nonlinear systems. Local convergence of the method is established under fairly mild assumptions, and examples are solved to demonstrate the effectiveness of the method. An extension of the approach to Lyapunov equations is also discussed. The preliminary results presented are promising, and it is hoped that the approach will ultimately develop into an efficient computational tool for solving the HJBIEs.

关键词： Affine nonlinear system bounded continuous function convergence Hamilton-Jacobi-Bellman-Isaacs equation Lyapunov equation relaxation method Riccati equation

Solution of nonlinear cubic-quintic duffing oscillators using He’s Energy Balance method

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1263-1268页

作者： d.d.GANJI m.GORJI S.SOLEImANI m.ESmAEILPOUR department of mechanical Engineering University of Mazandaran

In this study, He＇s Energy Balance method （EBm） was applied to solve strong nonlinear duffing oscillators with cubic-quintic nonlinear restoring force. The complete EBm solution procedure of the cubic-quintic duffing oscillator equation is presented. For illustration of effectiveness and convenience of the EBm, different cases of cubic-quintic duffing oscillator with different parameters of α,β and y were compared with the exact solution. We found that the solutions were valid for small as well as large amplitudes of oscillation. The results show that the EBm is very convenient and precise, so it can be widely appli- cable in engineering and other sciences.

关键词： Energy Balance method (EBm) Cubic-quintic duffing equation Oscillator

Analysis of turbulent mHd Couette nanofluid flow and heat transfer using hybrid dTm-Fdm

在线全文

学校读者我要写书评

暂无评论

Particuology 2016年第3期14卷 95-101页

作者： S. mosayebidorcheh m. Sheikholeslami m. Hatami d.d. Ganji Young Researchers and Elite Club Najafabad Branch lslamicAzad University Ndjafabad Iran department of mechanical Engineering Lenjan Branch Islamic Azad University lsfahan Iron department of mechanical Engineering Babol University of Technology Babol Iran mechanical Engineering department Engineering and Technical College Esfarayen University Esfarayen North Khorasan lran

Unsteady turbulent magnetohydrodynamic nanofluid hydrothermal treatment is studied. The zero- equation turbulence model is used to simulate turbulent flow. The modeling results obtained by applying the hybrid differential transformation method-finite difference method to solve this problem confirm its viability. An analytical procedure is used for finding the effects of the problem parameters. Results indicate that the average Nusselt number over the lower plate depends linearly on volume fraction of nanofluid, Hall parameter, turbulent Eckert number, and Reynolds number whereas it is inversely proportional on the Hartmann number and the turbulent parameter.

关键词： Turbulent Hall effect Hybrid dTm-Fdm Nanofluid magnetohydrodynarnic couette flow

Boundary conditions for porous solids saturated with viscous fluid

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

Applied mathematics and mechanics(English Edition) 2009年第7期30卷 821-832页

作者： m.d.Sharma department of mathematics Kurukshetra University

Boundary conditions are derived to represent the continuity requirements at the boundaries of a porous solid saturated with viscous fluid. They are derived from the physically grounded principles with a mathematical check on the conservation of energy. The poroelastic solid is a dissipative one for the presence of viscosity in the interstitial fluid. The dissipative stresses due to the viscosity of pore-fluid are well represented in the boundary conditions. The unequal particle motions of two constituents of porous aggre~ gate at a boundary between two solids are explained in terms of the drainage of pore-fluid leading to imperfect bonding. A mathematical model is derived for the partial connec- tion of surface pores at the porous-porous interface. At this interface, the loose-contact slipping and partial pore opening/connection may dissipate a part of strain energy. A numerical example shows that, at the interface between water and oil-saturated sandstone, the modified boundary conditions do affect the energies of the waves refracting into the isotropic porous medium.

关键词： porous solid dissipative boundary conditions

Advanced analytical determination of volatile organic compounds (VOC) and other major contaminants in water samples using GC-Ion Trap mS

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第1期13卷 25-36页

作者： B m Koroma K X Wang d d Jinya Laboratory of Socioeconomic Science of Food Production Nagoya University Japan.

The GC-Ion Trap mS is recently one of the most efficient instrumental analysis recommended for understanding the chemistry of volatile organic compounds, not only in water but even in the food chain and other environmental media (air and soil). Results of the experiment conducted on water samples from Kuguri and Yatsutani sampling stations showed considerably higher levels of organic enrichment (COd = 10 mg/L and 11 mg/L respectively). Total concentrations of Pb (0.072 mg/L and 0.093 mg/L) and Cd (0.004 mg/L and 0.011 mg/L) on the other hand, invariably exceeded the maximum allowable concentrations for human health and the living environment (Pb = 0.005 mg/L; Cd = 0.001 mg/L respectively). And the toxicity levels for these contaminants at LC50 showed critical impact on rainbow trout (hypersensitive species) at 0.14 mg/L for Pb and 0.007 mg/L for Cd in 96 hours respectively. Although these major contaminants including phenol and 3-, 4-cresol, showed relatively higher toxicity impact in the experimental media, it would remain contentious to justify any associated potential dangers without regular routine water monitoring, at least for a period of one year. Nevertheless, the data could serve as a benchmark through which other phenomena can easily be investigated.

关键词： www Advanced analytical determination of volatile organic compounds and other major contaminants in water samples using GC-Ion Trap mS VOC EB GC

Electrodeless plasma thrusters for spacecraft: a review

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2017年第8期19卷 1-24页

作者： S N BATHGATE m m m BILEK d R mCKENZIE Applied and Plasma Physics School of PhysicsUniversity of Sydney

The physics of electrodeless electric thrusters that use directed plasma to propel spacecraft without employing electrodes subject to plasma erosion is reviewed. Electrodeless plasma thrusters are potentially more durable than presently deployed thrusters that use electrodes such as gridded ion,Hall thrusters, arcjets and resistojets. Like other plasma thrusters, electrodeless thrusters have the advantage of reduced fuel mass compared to chemical thrusters that produce the same thrust. The status of electrodeless plasma thrusters that could be used in communications satellites and in spacecraft for interplanetary missions is examined. Electrodeless thrusters under development or planned for deployment include devices that use a rotating magnetic field; devices that use a rotating electric field; pulsed inductive devices that exploit the Lorentz force on an induced current loop in a plasma; devices that use radiofrequency fields to heat plasmas and have magnetic nozzles to accelerate the hot plasma and other devices that exploit the Lorentz force. Using metrics of specific impulse and thrust efficiency, we find that the most promising designs are those that use Lorentz forces directly to expel plasma and those that use magnetic nozzles to accelerate plasma.

关键词： spacecraft a review propellant Lorentz thrust rotating radiofrequency erosion presently exploit

Prediction and analysis of process failures by ANN classification during wire-Edm of Inconel 718

在线全文

学校读者我要写书评

暂无评论

Advances in manufacturing 2020年第4期8卷 519-536页

作者： Abhilash P.m. Chakradhar d. department of mechanical Engineering Indian Institute of Technology PalakkadPalakkadKeralaIndia

Wire breakages and spark absence are two typical machining failures that occur during wire electric discharge machining(wire-Edm),if appropriate parameter settings are not *** after several attempts to optimize the process,machining failures cannot be eliminated completely.A n offline classification model is presented herein to predict machining *** aim of the current study is to develop a multiclass classification model using an artificial neural network(ANN).The training dataset comprises 81 full factorial experiments with three levels of pulse-on time,pulse-off time,servo voltage,and wire feed rate as input *** classes are labeled as normal machining,spark absence,and wire *** model accuracy is tested by conducting 20 confirmation experiments,and the model is discovered to be 95%accurate in classifying the machining *** effects of process parameters on the process failures are discussed and analyzed.A microstructural analysis of the machined surface and worn wire surface is *** developed model proved to be an easy and fast solution for verifying and eliminating process failures.

关键词： Wire electric discharge machining(wire-Edm) Process failure Spark absence Wire breakage Artificial neural network(ANN)classification Failure prediction

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

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

Neural Regeneration Research 2025年第4期20卷 1192-1206页

作者： Tyler A.Smith Liwen Zhou Cameron L.Ghergherehchi michelle mikesh Cathy Z.Yang Haley O.Tucker JuliAnne Allgood Jared S.Bushman George d.Bittner department of molecular Biosciences University of Texas at AustinAustinTXUSA department of Neuroscience University of Texas at AustinAustinTXUSA division of Pharmaceutical Sciences University of WyomingLaramieWYUSA

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal ***,such peripheral nerve allografts undergo immunological rejection by the host immune *** contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian *** relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this *** hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral *** examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal ***-type sciatic nerve injuries in outbred Sprague–dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host *** to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days *** morphological signs of rejection,such as col

关键词： allograft rejection axotomy macrophage myelin nerve repair polyethylene glycol(PEG) sciatic nerve T cell transplantation Wallerian degeneration

Computational Studies of Flow through Cross Flow Fans-Effect of Blade Geometry

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2005年第3期14卷 220-229页

作者： m . GOVARdHAN d. LAKSHmANA SAmPAT School of mechanical Engineering Universiti Malaysia Sabah Sabah Malaysia ProfessorThermal Turbomachines Laboratory Department of Mechanical Engineering Indian Institute of Technology Madras Chennai India

This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFd) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.

关键词： cross flow fans computational fluid dynamics quasi steady state multiple frames of reference

modelling two-layer nanofluid flow in a micro-channel with electro-osmotic effects by means of Buongiorno’s model

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2020年第1期41卷 83-104页

作者： m.d.K.NIAZI Hang XU State Key Lab of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE)School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong University

A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic ***’s model is employed for describing the behavior of *** from the previous studies on two-layer channel flow of a nanofluid,the present paper introduces the flux conservation conditions for the nanoparticle volume fraction field,which makes this work new and unique,and it is in coincidence with practical *** governing equations are reduced into a group of ordinary differential equations via appropriate similarity *** highly accurate analytical approximations are *** physical quantities and total entropy generation are analyzed and discussed.A comparison is made to determine the significance of electrical double layer(EdL)effects in the presence of an external electric *** is found that the Brownian diffusion,the thermophoresis diffusion,and the viscosity have significant effects on altering the flow behaviors.

关键词： electrical double layer(EdL) entropy generation micro-channel nanofluid