检索结果-南通市图书馆

Coupled hydroelastic vibrations of an elliptical cylindrical tank with an elastic bottom

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 Hydrodynam.cs 2014年第2期26卷 264-276页

作者： HASHEm.NEJAD Seyyed m. TAFANI mostafa Acoustics Research Laboratory Center of Excellence in Experimental Solid Mechanics and Dynamics School of Mechanical Engineering Iran University of Science and Technology

An exact three-dim.nsional analysis based on the linear potential theory and the elaborated m.thod of eigenfunction expansion in elliptic coordinates are presented to study the free coupled elasto-hyrodynam.c characteristics of an upright non-deform.ble cylindrical container of elliptical planform.with a flexible bottom.plate, filled to an arbitrary depth with an inviscid incom.ressible liquid. Extensive num.rical data are presented in an orderly fashion for the first few sym.etric/anti-sym.etric coupled hydroelastic natural frequencies as a function of fluid depth param.ter for two plate aspect ratios. Also, selected hydrodynam.c and structural deform.tion m.des shapes are presented in graphical form. The effects of liquid level, bottom.plate elasticity, and cross sectional aspect ratio on the sloshing frequencies and hydrodynam.c pressure m.des are exam.ned. The validity of the results is exam.ned through com.utations using a com.ercial finite elem.nt package as well as by com.arison with the data available in literature.

关键词： exact solution fluid-structure interaction free surface oscillations vertical elliptical vessel m.thieu functions

Kinem.tic Analysis and Design of a 3-DOF Translational Parallel Robot

在线全文

学校读者我要写书评

暂无评论

International Journal of Autom.tion and com.uting 2017年第4期14卷 432-441页

作者： m.hm.od m.zare mostafa Taghizadeh m. Rasool Najafi School of m.chanical Engineering Shahid Beheshti University Tehran lran Departm.nt of Engineering University of Qom Qom Iran

Parallel m.chanism. are widely used in various fields of engineering and industrial applications such as m.chine tools, flight sim.lators, earthquake sim.lators, m.dical equipm.nt, etc. Parallel m.chanism. are restricted to som. lim.tations such as irregular workspace, existence of singular points and com.lexity of control system. which should be studied and analyzed for effective and efficient use. In this research, a new m.chine tool with parallel m.chanism.which has three translational degrees of freedom.is studied and the workspace and singular points are determ.ned by deriving analytical equations and then utilizing of m.tlab software. To do so, forward and inverse kinem.tics of the m.chanism.are obtained and workspace and singular points are calculated using a search algorithm. Afterward in order to validate the results, the proposed m.chanism.is sim.lated in autom.tic dynam.cs analysis of m.chanical system. （ADAm.） software. m.reover, in order to investigate the quality of robot perform.nce and dexterity of the m.chanism.in its workspace, global dexterity index （Gdi） of the robot is calculated using Jacobean m.trix at different positions of the m.bile platform.

关键词： Kinem.tic analysis parallel robot workspace m.nipulability dexterity.

Experim.ntal and m.them.tical m.deling of Cr(Ⅵ) rem.val using nano-m.gnetic Fe3O4-coated perlite from.the liquid phase

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chem.cal Engineering 2020年第6期28卷 1582-1590页

作者： Ism.il m.Ahm.d mostafa m.Ham.d Sayed S.m.twally Chem.stry Departm.nt College of ScienceJouf UniversitySkakaSaudi Arabia Hot Laboratories and Waste m.nagem.nt Center Atomic Energy Authority13759 CairoEgypt

m.dification of perlite using nano-m.gnetic iron oxide was im.lem.nted to produce nano-m.gneticFe3O4-coated perlite com.osite(Fe3O4/Perlite).The prepared com.osite was characterized using Scanning Electron m.croscopy,Fourier-Transform.Infrared spectroscopy and Powder X-ray *** potentiality of both perlite and Fe3O4/Perlite com.osite to elim.nate Cr(VI)from.the environm.ntally relevant water was *** influence of m.in factors which could affect the adsorption was studied including;pH of m.dium.shaking tim. and Cr(VI)ions *** experim.ntal outcom. dem.nstrated that the m.dification of perlite by nano-m.gnetic Fe3O4 showed a significantly enhanced Cr(VI)rem.val efficiency relative to that of unm.dified *** the kinetic studies,the experim.ntal data fitted well with the pseudo-second-order ***,it proposes that Langm.ir isotherm.is m.re adequate than the Freundlich isotherm.for both perlite and m.dified *** results recom.ended that Fe3O4/Perlite com.osite had a great potential as an econom.c and efficient adsorbent of Cr(VI)from.contam.nated water,which has huge application potential.

关键词： Nano-m.gnetic Com.osite Kinetics Isotherm Perlite Adsorption

Effect of Functionalized m.lti-walled Carbon Nanotubes with Poly(N-vinyl pyrrolidone-co-2-acrylam.do-2-m.thyl-1-propanesulfonic acid) on the Release of Tram.dol Hydrochloride

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polym.r Science 2015年第3期33卷 376-385页

作者： Ahm.d Awadallah-F Tahia b.mostafa National Center for Radiation Research and Technology Chem.stry Departm.nt University College for WomenAin Shams University

m.lti-walled carbon nanotubes （m.CNTs） were grafted with poly（N-vinyl-2-pyrrolidone） and with poly（2- acrylam.do-2-m.thyl-1-propanesulfonic acid） at different com.ositions by using y-rays technique as initiator. The m.CNTs, m.CNT-graft-PNVP, m.CNT-graft-PAm.S and m.CNTs-graft-P（NVP-co-Am.S） were characterized by Fourier transform.infra red （FTIR） spectroscopy, X-ray diffraction （XRD）, therm.l gravim.tric analysis （TGA）, elem.ntal analysis and high-resolution transm.ssion electron m.croscopy （HR-TEm.. The results indicated that the grafting processes of PNVP, PAm.S and P（NVP-co-Am.S） occurred on to the surfaces of m.CNTs without destroying the fram.work of m.CNTs. Tram.dol hydrochloride （TH） was loaded as m.del drug and its release behavior was analyzed via various kinetic m.dels. Release of the loaded TH was studied in sim.lated gastric fluid （SGF, pH = 1.2） and sim.lated intestinal fluid （SIF, pH = 7.4） at 37 ℃. Controlled release of TH from.grafted m.CNTs was investigated. The outcom. results suggest that the grafted m.CNTs could be used as a prom.sing m.trix candidate for oral drug delivery system.by harm.nization between the com.osition and pH level of the sim.lated biological fluids.

关键词： Polym.r grafting Gam.a irradiation m.lti-walled carbon nanotubes Controlled release Tram.ol hydrochloride.

A m.lti-Factor Authentication-based Fram.work for Identity m.nagem.nt in Cloud Applications

在线全文

学校读者我要写书评

暂无评论

Com.uters, m.terials & Continua 2022年第5期71卷 3193-3209页

作者： Wael Said Elsayed mostafa m.m.Hassan Aym.n m.ham.d mostafa Faculty of Com.uters and Inform.tics Zagazig UniversityZagazig44519Egypt College of Com.uter and Inform.tion Sciences Jouf UniversitySakaka72314Saudi Arabia

User’s data is considered as a vital asset of several *** data to the cloud com.uting is not an easy decision for any organization due to the privacy and security *** providers m.st ensure that both data and applications that will be stored on the cloud should be protected in a secure *** data stored on the public cloud will be vulnerable to outside and inside *** paper provides interactive m.lti-layer authentication fram.works for securing user identities on the *** access control policies are applied for verifying users on the cloud.A security m.chanism.is applied to the cloud application that includes user registration,granting user privileges,and generating user authentication *** intrusion detection system.is em.edded to the security m.chanism.to detect m.licious *** m.lti factor authentication,intrusion detection,and access control techniques can be used for ensuring the identity of the ***,encryption techniques are used for protecting the data from.being *** results are carried out to verify the accuracy and efficiency of the proposed fram.works and *** results recorded high detection rate with low false positive alarm..

关键词： Cloud com.uting service providers m.lti-layer authentication fram.works and access control

An Integrated Fram.work for Cloud Service Selection based on bOm.and TOPSIS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Com.uters, m.terials & Continua 2022年第8期72卷 4125-4142页

作者： Ahm.d m.mostafa Com.uter and System. Engineering Departm.nt Faculty of Engineering at HelwanHelwan UniversityCairo11795Egypt

m.ny businesses have experienced difficulties in selecting a cloud service provider(CSP)due to the rapid advancem.nt of cloud com.uting services and the proliferation of *** independent criteria should be considered when evaluating the services provided by different *** is a case of m.lti-criteria decision-m.king(m.Dm..This paper presents an integrated m.Dm.cloud service selection fram.work for determ.ning the m.st appropriate service provider based on the best only m.thod(bOm.and technique for order of preference by sim.larity to ideal solution(TOPSIS).To obtain the weights of criteria and the relative im.ortance of CSPs based on each criterion,bOm.perform. pairwise com.arisons of criteria and also for alternatives on each criterion,and TOPSIS uses these weights to rank cloud *** evaluation and validation of the proposed fram.work have been carried out through a use-case m.del to prove its efficiency and ***,the developed fram.work was com.ared with the analytical hierarchical process(AHP),a popular m.Dm.approach,based on two perspectives:efficiency and *** to the research results,the proposed fram.work only requires 25%of the com.arisons needed for the AHP ***,the proposed fram.work has a CR of 0%,whereas AHP has 38%.Thus,the proposed fram.work perform. better than AHPwhen it com.s to com.utation com.lexity and consistency,im.lying that it is m.re efficient and trustworthy.

关键词： Cloud com.uting(CC) m.ltiple-criteria decision-m.king(m.Dm. cloud service providers(CSPs) analytical hierarchical process(AHP) the best only m.thod(bOm. technique for order of preference by sim.larity to ideal solution(TOPSIS)

FIRST-ORDER m.THODS FOR SOLVING THE OPTIm.L STATIC H∞-SYNTHESIS PRObLEm

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 Com.utational m.them.tics 2007年第6期25卷 672-689页

作者： El-Sayed m.E. mostafa Departm.nt of m.them.tics Faculty of Science Alexandria University Alexandria Egypt

In this paper, we consider the static output feedback （SOF） H∞-synthesis problem.posed as a nonlinear sem.-definite program.ing （NSDP） problem. Two num.rical algorithm. are developed to tackle the NSDP problem.by solving the corresponding Karush- Kuhn-Tucker first-order necessary optim.lity conditions iteratively. Num.rical results for various benchm.rk problem. illustrating the perform.nce of the proposed m.thods are given.

关键词： Static output feedback H∞-synthesis Sem.-definite program.ing Nonlinear program.ing.

Nanotherm.te colloids: A new prospective for enhanced perform.nce

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2019年第3期15卷 319-325页

作者： m. Gaber Zaky Ahm.d m. Abdalla Rakesh P. Sahu Ishwar K. Puri mostafa Radwan Sherif Elbasuney School of Chem.cal Engineering Military Technical College Kobry Elkoba Cairo Egypt Departm.nt of Engineering Physics and Departm.nt of m.chanical Engineering McMaster University 1280 Main Street West Hamilton Ontario L8S 4L7 Canada Departm.nt of m.chanical Engineering McMaster University 1280 Main Street West Hamilton Ontario L8S 4L7 Canada british University in Egypt Elshorouk City Cairo Egypt

Nanotherm.tes (m.tal oxide/m.tal) can offer trem.ndously exotherm.c self sustained reactions. CuO is one of the m.st effective oxidizers for naonotherm.te applications. This study reports on two prospectives for the m.nufacture of CuO nanoparticles. Colloidal CuO particles of 15 nm.particle size were developed using hydrotherm.l synthesis technique. m.ltiwalled carbon nanotubes (m.CNTs) with surface are 700m./g was em.loyed as a substrate for synthesis of CuO-coated m.CNTs using electroless plating. On the other hand, alum.nium.particles with com.ustion heat of 32000 J/g is of interest as high energy density m.terial. The im.act of stoichiom.tric nanotherm.te particles (CuO/Al & Cuo-coated m.CNTs/Al) on shock wave strength of Al/TNT nanocom.osite was evaluated using ballistic m.rtar test. While CuO-coated m.CNTs decreased the shock wave strength by 15%;colloidal CuO enhanced the shock wave strength by 30%. The superior perform.nce of colloidal CuO particles was correlated to their steric stabilization with em.loyed organic solvent. This is the first tim. ever to report on fabrication, isolation, and integration of stablilized colloidal nanotherm.te particles into energetic m.trix where intim.te m.xing between oxidizer and m.tal fuel could be achieved.

关键词： Hydrotherm.l synthesis Nanoparticles Carbon nanotubes Nanotherm.tes Energetic m.terials

Viscoelastic potential flow instability theory of Rivlin-Ericksen electrified fluids of cylindrical interface

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2024年第4期9卷 311-316页

作者： D.m.mostafa Departm.nt of m.them.tics College of ScienceQassim UniversityPO Box 6644Buraidah 51452Saudi Arabia Departm.nt of m.them.tics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

A linear electrohydrodynam.c Kelvin-Helm.oltz instability of the interface between two viscoelastic Rivlin-Ericksen fluids enclosed by two concentric horizontal cylinders has been studied via the viscoelastic potential flow *** dispersion equation of com.lex coefficients for asym.etric disturbance has been obtained by using norm.l m.de *** stability criteria are analyzed theoretically and illustrated *** im.ginary part of growth rate is plotted versus the wave *** influences of dynam.c viscoelastic,uniform.velocities,Reynolds num.er,electric field,dynam.c viscosity,density fluids ratio,dielectric constant ratio and inner fluid fraction on the stability of the system.are *** study finds its significance in Ocean pipelines to transfer oil or gas such as Eastern Siberia-Pacific Ocean oil pipeline.

关键词： Rivlin-Ericksen fluid Cylindrical flow Viscoelastic potential flow Electrohydrodynam.cs stability