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Human reliability analysis in maintenance team of power transmission system protection

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Protection and Control of Modern Power Systems 2020年第1期5卷 290-302页

作者： mehdi Tavakoli mehdi Nafar Department of Electrical Engineering Marvdasht BranchIslamic Azad UniversityMarvdashtIran

The requirement for reliable electrical energy supply increases continuously because of its vital role in our ***,events due to various factors in the power grid can cause energy supply to be *** of these factors is human error and thus human reliability analysis is a serious element in the *** first step is to identify the roots of human error,on which there has been limited research in this *** this paper,the potential and actual causes of human error in maintenance teams of power transmission system protection are identified and predicted within a framework of human factors analysis and classification system ***,human error factors are ranked to help improve human *** proposed method is implemented in the Fars Electricity Maintenance Company.

关键词： Power transmission system protection Maintenance teams Human reliability HFACS method

Movement of Intransitive Permutation Groups Having Maximum Degree

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Chinese Annals of Mathematics,Series B 2012年第1期33卷 143-148页

作者： mehdi ALAEIYAN mehdi REZAEI School of Mathematics Iran University of Science and Technology

Let G be a permutation group positive integer. Then the movement of G on a set Ω with no fixed points in Ω, and m be a is defined as move（G）：=supГ{[Г^9 ／Г｜｜g ∈ G}. It F was shown by Praeger that if move（G） = m, then ｜Ω｜ ≤ 3m ＋ t - 1, where t is the number of G-orbits on ≤. In this paper, all intransitive permutation groups with degree 3m ＋ t - 1 which have maximum bound are classified. Indeed, a positive answer to her question that whether the upper bound ｜Ω｜ = 3m ＋ t - 1 for ｜Ω｜ is sharp for every t 〉 1 is given.

关键词： Intransitive permutation groups Bounded movement Orbit

Transport of Jeffrey fluid in a rectangular slit of the microchannel under the effect of uniform reabsorption and a porous medium

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Communications in Theoretical Physics 2021年第11期73卷 31-46页

作者： H Mehboob K maqbool R Ellahi Sadiq M Sait Department of Mathematics and Statistics International Islamic UniversityIslamabadPakistan Center for Modeling&Computer Simulation Research InstituteKing Fahd University of Petroleum&MineralsDhahran-31261Saudi Arabia Fulbright Fellow Department of Mechanical EngineeringUniversity of California RiversideUnited States of America Centre for Communications and IT Research Research InstituteKing Fahd University of Petroleum&MineralsDhahran-31261Saudi Arabia

This research explores the transport of a Jeffrey fluid through a permeable slit of microchannel under the effect of a porous medium and constant *** laws of fluid mechanics are used to study the flow in a cross-sectional area of a narrow slit which generates a highly nonlinear system of partial differential equation with nonhomogeneous boundary *** solve the complex boundary value problem;a recursive(Langlois)approach is used and explicit expressions for velocity,pressure,stream function,flux,shear stress and fractional reabsorption are *** is noticed that the flow rate at the centre line of slit and shear stress on the walls of slit decay due to the presence of porous medium and viscoelastic fluid *** is also quantitatively observed that more pressure is required for the fluid flow when the slit is filled with a porous medium and reabsorption on the walls is *** mathematical results of the present research have significant importance in the field of biofluid mechanics and medical industry,therefore the application of a diseased rat kidney is also included in this research:and reabsorption velocities in the case of a diseased and a healthy rat kidney are calculated with the effects of a porous medium and constant re-absorption.

关键词： creeping flow Jeffrey fluid uniform re-absorption porous medium permeable slit micro channel Langlois approach

Kinetic studies of the oxidative coupling of methane over the Mn/Na_2WO_4/SiO_2 catalyst

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Journal of Natural Gas Chemistry 2009年第1期18卷 25-34页

作者： Seyed mehdi Kamali Shahri Seyed mehdi Alavi Reaction Engineering Lab. Chemical Engineering Department Iran University of Science and Technology Tehran-Iran

Oxidative coupling of methane is a direct way to obtain C2 hydrocarbon, and Mn-Na-W/SiO2 catalyst is the most promising among all the catalysts. The 2%Mn/5%Na2WO4/SiO2 catalyst was prepared by the incipient wetness impregnation method. A 7-step heterogeneous reaction model of the oxidative coupling of methane to C2 hydrocarbons was conducted by co-feeding methane and oxygen at a total pressure of 1 bar over the catalyst. The kinetic measurements were carried out in a micro-catalytic fixed bed reactor. The kinetic data were obtained at the appropriate range of reaction conditions （4 kPa〈Po2 〈20 kPa, 20 kPa〈PcH4〈80 kPa, 800 ℃〈T〈900℃）. The proposed reaction kinetic scheme consists of three primary and four consecutive reaction steps. The conversions of hydrocarbons and carbon oxides were evaluated by applying Langmuir-Hinshelwood type rate equations. Power-law rate equation was applied only for the water-gas shift reaction. In addition, the effects of operating conditions on the reaction rate were studied. The proposed kinetic model can predict the conversion of methane and oxygen as well as the yield of C2 hydrocarbons and carbon oxides with an average accuracy of ± 15%.

关键词： kinetic model oxidative coupling of methane reaction rate

Cognitive Power Management in Wireless Sensor Networks

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Journal of Computer Science & Technology 2015年第6期30卷 1306-1317页

作者： Seyed mehdi Tabatabaei Vesal Hakami mehdi Dehghan Department of Computer Engineering and Information Technology Amirkabir University of Technology Tehran 16846-13114 Iran

Dynamic power management （DPM） in wireless sensor nodes is a well-known technique for reducing idle energy consumption. DPM controls a node＇s operating mode by dynamically toggling the on/off status of its units based on predictions of event occurrences. However, since each mode change induces some overhead in its own right, guaranteeing DPM＇s eificiency is no mean feat in environments exhibiting non-determinism and uncertainty with unknown statistics. Our solution suite in this paper, collectively referred to as cognitive power management （CPM）, is a principled attempt toward enabling DPM in statistically unknown settings and gives two different analytical guarantees. Our first design is based on learning automata and guarantees better-than-pure-chance DPM in the face of non-stationary event processes. Our second solution caters tor an even more general setting in which event occurrences may take on an adversarial character. In this case, we formulate the interaction of an individual mote with its environment in terms of a repeated zero-sum game in which the node relies on a no-external-regret procedure to learn its mini-max strategies in an online fashion. We conduct numerical experiments to measure the performance of our schemes in terms of network lifetime and event loss percentage.

关键词： wireless sensor network cognitive power management learning automata external regret zero-sum game

Hall Effect on Falkner–Skan Boundary Layer Flow of FENE-P Fluid over a Stretching Sheet

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Communications in Theoretical Physics 2016年第11期65卷 547-554页

作者： Khadija maqbool Ayesha Sohail Naeema Manzoor Rahmat Ellahi Department of Mathematics&Statistics FBASIIUIIslamabadPakistan Department of Mathematics Comsats Institute of Information TechnologyLahorePakistan Department of Mechanical Engineering University of California RiversideUSA

The Falkner-Skan boundary layer steady flow over a fiat stretching sheet is investigated in this paper. The mathematical model consists of continuity and the momentum equations, while a new model is proposed for MHD Finitely Extensible Nonlinear Elastic Peterlin （FENE-P） fluid. The effects of Hall current with the variation of intensity of non-zero pressure gradient are taken into account. The governing partial differential equations are first transformed to ordinary differential equations using appropriate similarity transformation and then solved by Adomian decomposition method （ADM）. The obtained results are validated by generalized collocation method （GCM） and found to be in good agreement. Effects of pertinent parameters are discussed through graphs and tables. Comparison with the existing studies is made as a limiting case of the considered problem at the end.

关键词： FENE-P fluid MHD Hall effect viscoelastic fluid stretching sheet skin friction

Porosity parameters in biomaterial science: Definition, impact, and challenges in tissue engineering

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Frontiers of Materials Science 2021年第3期15卷 352-373页

作者： mehdi EBRAHIMI Biomedical and Tissue Engineering Prince Philip Dental HospitalThe University of Hong KongHong KongChina

Porosity parameters are one of the structural properties of the extracellular microenvironment that have been shown to have a great impact on the cellular phenotype and various biological activities such as diffusion of fluid,initial protein adsorption,permeability,cell penetration and migration,ECM deposition,angiogenesis,and rate and pattern of new tissue *** heterogeneity of the study protocols and research methodologies do not allow reliable meta-analysis for definite *** such,despite the huge available literature,no generally accepted consensus is defined for the porosity requirements of specific tissue engineering ***,based on the biomimetic approach,the biological substitutes should replicate the 3D local microenvironment of the recipient site with matching porosity parameters to best support local cells during tissue ***,the porosity of biomaterials should mimic the porosity of the substituting natural tissue and match the clinical *** analysis of the impact of architectures(i.e.,porosity)on biophysical,biochemical,and biological behaviors will support designing smart biomaterials with customized architectural and functional properties that are patient and defect site-specific.

关键词： porosity pore size pore geometry topography tissue engineering

Cost effective use of mosquito net mesh in inguinal hernia repair

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The Journal of Biomedical Research 2019年第5期33卷 351-356页

作者： Mudassir maqbool Wani Abdul Munnan Durrani Department of Surgery King Khalid UniversityAbha 61321Saudi Arabia Department of Surgery Jaypee HospitalNoida 110996India.

Mesh hernia repair is one of the commonest open techniques of inguinal hernia *** main limiting factor in the use of new meshes is the *** carried out a prospective randomized double blind study and comprising of a hundred patients with 100 inguinal hernias admitted consecutively for elective surgery,divided into the polypropylene mesh(PPM)group and the mosquito net mesh(MNM)group each containing fifty *** cases were completed successfully and results revealed no difference in two *** results of the present study,in consistent with the published literature,reveal that the cheap indigenous mosquito mesh,which has similar properties of an imported mesh,can be safely used for tension-free inguinal hernia repair in *** trials with a larger number of patients and longer follow-ups are justified and recommended.

关键词： cost effective mesh mosquito mesh polypropylene mesh Lichtenstein's repair inguinal hernia

Introducing the general condition for an operator in curved space to be unitary

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Chinese Physics B 2021年第8期30卷 220-223页

作者： Jafari Matehkolaee mehdi Faculty of Physics Semnan UniversitySemnan35131-19111Iran

We investigate the general condition for an operator to be *** condition is introduced according to the definition of the position operator in curved *** a particular case,we discuss the concept of translation operator in curved space followed by its relation with an anti-Hermitian *** we introduce a universal formula for adjoint of an arbitrary linear *** procedure in this paper is totally different from others,as we explore a general approach based only on the algebra of the *** approach is only discussed for the translation operators in one-dimensional space and not for general operators.

关键词： operator theory algebraic methods unitary operator translation operator