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Numerical Investigation on th. Effects of Design Parameters and Operating Conditions on th. Electroch.mical Performance of Proton Exch.nge Membrane Water Electrolysis

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Journal of Th.rmal Science 2023年第6期32卷 1989-2007页

作者： hassan alamir h. WANG Xueye LIAO Zh.rong Xu Ch.o Key Laboratory of Power Station Energy Transfer Conversion and System of MOE School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China Mech.nical Power Engineering Department Faculty of Engineering-MattariaHelwan UniversityCairo11718Egypt

Proton exch.nge membrane electrolysis cell(PEMEC)is one of th. most promising meth.ds to produce h.drogen at h.gh.purity and low power *** th.s study,a th.ee-dimensional non-isoth.rmal model is used to simulate th. cell performance of a typical PEMEC based on computational fluid dynamics(CFD)with.th. finite element ***,th. model is used to investigate th. distributions of current density,species concentration,and temperature at th. membrane/catalyst(MEM/CL)***,th. effects of operating conditions and design parameters on th. polarization curve,specific electrical energy demand,and electrical cell efficiency are *** results sh.w th.t th. maximum distribution of current density,h.drogen concentration,oxygen concentration,and temperature occur beneath.th. core ribs and increase towards th. ch.nnel outlet,wh.le th. maximum water concentration distribution h.ppens under th. ch.nnel and decreases towards th. ch.nnel exit *** increase in gas diffusion layer(GDL)th.ckness reduces th. uneven distribution of th. contour at th. MEM/CL *** is also found th.t increasing th. operating temperature from 323 K to 363 K reduces th. cell voltage and specific energy *** h.drogen ion diffusion degrades with.increasing th. cath.de pressure,wh.ch.increases th. specific energy demand and reduces th. electrical cell ***,increasing th. th.ckness of th. GDL and membrane rises th. specific energy demand and lowers th. electrical efficiency,but increasing GDL porosity reduces th. specific electrical energy demand and improves th. electrical cell efficiency;th.s using a th.n membrane and GDL is recommended.

关键词： h.drogen production proton exch.nge membrane water electrolysis gas diffusion layer cell efficiency

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Experimental investigation of control updating period monitoring in industrial PLC-based fast MPC： Application to th. constrained control of a cryogenic refrigerator

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Control Th.ory and Tech.ology 2017年第2期15卷 92-108页

作者： Francois BONNE Mazen alamir Patrick BONNAY Universite Grenoble Alpes INAC-SBT F-38000 Grenoble France CNRS Gipsa-lab Universite Grenoble Alpes F-3800 Grenoble France

In th.s paper, a complete industrial validation of a recently publish.d sch.me for on-line adaptation of th. control updating period in model predictive control is proposed. Th. industrial process th.t serves in th. validation is a cryogenic refrigerator th.t is used to cool th. supra-conductors involved in particle accelerators or experimental nuclear reactors. Two recently predicted features are validated： th. first states th.t it is sometimes better to use less efficient （per iteration） optimizer if th. lack of efficiency is overmcompensated by an increase in th. updating control frequency. Th. second is th.t for a given solver, it is worth.monitoring th. control updating period based on th. on-line measured beh.vior of th. cost function.

关键词： Fast MPC cryogenic refrigerators control updating period ODE-based optimization

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Combination of Model-based Observer and Support Vector Mach.nes for Fault Detection of Wind Turbines

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International Journal of Automation and computing 2014年第3期11卷 274-287页

作者： Nassim Laouti Sami Oth.an Mazen alamir Nida Sh.ibat-Oth.an Université de Lyon Université Lyon 1 CNRS CPE Lyon UMR 5007 LAGEP F-69616 Villeurbanne France Gipsa-lab/CNRS University of Grenoble Rue de la Houille Blanche 38400 Saint Martin d Heres France

Support vector mach.nes and a Kalman-like observer are used for fault detection and isolation in a variable speed h.rizontalaxis wind turbine composed of th.ee blades and a full converter. Th. support vector approach.is data-based and is th.refore robust to process knowledge. It is based on structural risk minimization wh.ch.enh.nces generalization even with.small training data set and it allows for process nonlinearity by using flexible kernels. In th.s work, a radial basis function is used as th. kernel. Different parts of th. process are investigated including actuators and sensors faults. With.duplicated sensors, sensor faults in blade pitch.positions,generator and rotor speeds can be detected. Faults of type stuck measurements can be detected in 2 sampling periods. Th. detection time of offset/scaled measurements depends on th. severity of th. fault and on th. process dynamics wh.n th. fault occurs. Th. converter torque actuator fault can be detected with.n 2 sampling periods. Faults in th. actuators of th. pitch.systems represents a h.gh.r difficulty for fault detection wh.ch.is due to th. fact th.t such.faults only affect th. transitory state(wh.ch.is very fast) but not th. final stationary state. Th.refore, two meth.ds are considered and compared for fault detection and isolation of th.s fault: support vector mach.nes and a Kalman-like observer. Advantages and disadvantages of each.meth.d are discussed. On one h.nd, support vector mach.nes training of transitory states would require a big amount of data in different situations, but th. fault detection and isolation results are robust to variations in th. input/operating point. On th. oth.r h.nd, th. observer is model-based, and th.refore does not require training, and it allows identification of th. fault level, wh.ch.is interesting for fault reconfiguration. But th. observability of th. system is ensured under specific conditions, related to th. dynamics of th. inputs and outputs. Th. wh.le fault detection

关键词： Fault detection and isolation wind turbine Kalman-like observer support vector mach.nes data-based classification

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A ph.se-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

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Control Th.ory and Tech.ology 2021年第1期19卷 49-63页

作者： Baoling Guo Seddik Bach. Mazen alamir Julien Pouget Sch.ol of Engineering.(h.S SO)Universily of Applied Sciences and Arts of Western Switzeland Sion1950 ValaisSwitzerland Institute of Engineering Grenoble University Grenoble AlpesCNRSG2Elab38000 GrenobleFrance Institute of Engineering Grenoble University Grenoble AlpesCNRSGIPSA-Lab38400 Saint Martin D'HeresFrance

An extended state observer(ESO)-based loop filter is designed for th. ph.se-locked loop(PLL)involved in a disturbed grid-connected converter(GeC).Th.s ESO-based design enh.nces th. performances and robustness of th. PLL,and,th.refore,improves control performances of th. disturbed ***,th. ESO-based LF can be applied to PLLs with.extra filters for abnormal grid *** unbalanced grid is particularly taken into account for th. performance analysis.A tuning approach.based on th. well-designed PI controller is discussed,wh.ch.results in a fair comparison with.conventional PI-type *** frequency domain properies are quantitatively analysed with.respeet to th. control stability and th. noises *** frequency domain analysis and simulation results suggesti th.t th. performances of th. generated ESO-based controllers are comparable to th.se of th. PI control at low frequency,wh.le h.ve better ability to atenuate h.gh.frequency measurement *** ph.se margin decreases sligh.ly,but remains ***,experimental tests are conducted with.a h.brid power h.rdwarein-th.-loop bench.ark,in wh.ch.balanced/unbalanced cases are both.*** obtained results prove th. effectiveness of ESO based PLLs wh.n applied to th. disturbed GeC.

关键词： Grid-conected converters Grid disturbances Ph.se-locked loop Loop filter Extended state observer Tuning approach Stability analysis Ph.se margin Noises attenuation Power h.rdware-in-th.-loop(Ph.L)test

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中国对埃塞尔比亚的直接投资及其影响（2002-2018）

中国对埃塞尔比亚的直接投资及其影响（2002-2018）

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作者： Temesgen alamir 吉林大学

学位级别：硕士

本文研究的目的是通过分析外国直接投资的政策和动机来探讨中国自2002年以来对埃塞俄比亚的投资所产生的影响。本文重点是调查中国的直接投资是否有助于埃塞俄比亚的工业化、基础设施建设、创造就业以及技术和知识向经济发展方面转移。... 详细信息

本文研究的目的是通过分析外国直接投资的政策和动机来探讨中国自2002年以来对埃塞俄比亚的投资所产生的影响。本文重点是调查中国的直接投资是否有助于埃塞俄比亚的工业化、基础设施建设、创造就业以及技术和知识向经济发展方面转移。本文研究显示,中国是在埃塞俄比亚经济发展的基础上,根据该国创造的投资条件来进行投资。在方法论上,本文研究主要采用定性方法,试图通过这种方法来检验中国对埃塞俄比亚投资的成就和有效性。本文提出的研究问题是“中国对埃塞俄比亚的投资对当地带来的经济影响是什么?”为了回答上述问题,本文分析了中国投资对埃塞俄比亚经济所产生的实际贡献。埃塞俄比亚至少20年没有颁布过鼓励国内外公司的指导政策和战略。但是在新的领导政府于2001年上台后,埃塞俄比亚制定了相关的产业政策和战略,以吸引外资提升全国工业化水平。本文一共分为五章:第一章试图阐明本文的背景、意义、研究问题、主要论点、文献综述和理论方法等。第二章主要描写中国在基础设施方面的投资以及中国的投资在埃塞俄比亚建立经济特区的状况,这部分研究阐述了中国政府参与埃塞俄比亚建设的作用,其直接投资有助于埃塞俄比亚经济基础设施的发展。第三章论述了中国直接投资在埃塞俄比亚工业化中的作用、中国在埃塞俄比亚的投资和发展经验以及对埃塞俄比亚工业化发展模式的详细分析。第四章则着重关注中国对埃塞俄比亚的直接投资成果,包括经济成就、技术扩散和知识转移以及人力资本积累等。本文最后一章是结论和建议。中国和埃塞俄比亚两国之间的经济关系不断加强。埃塞俄比亚与中国建立经济联系的原因有很多,主要是中国长期处于国际事务的战略位置,中国的直接投资促进了埃塞俄比亚整体经济增长,同时中国也需要利用埃塞俄比亚来扩大出口。所以目前中华人民共和国是埃塞俄比亚的主要商业和投资伙伴。埃塞俄比亚对于中国而言有着许多的吸引因素,包括:稳定的投资环境、丰富的人力资源、低廉的劳动力成本、部门之间灵活合作的管理系统、收入和税收管理中心的问责制和透明度以及埃塞俄比亚政府的跨境激励措施等。中国的直接投资为埃塞俄比亚提供了重要支持,包括基础设施发展(公路、铁路、水力发电等)、工业化发展、技术扩散、金融增长等方面。中国与埃塞俄比亚两国还着重发展了农业。根据协议,中国政府为埃塞俄比亚政府领导人和公务员提供短期和长期培训等。总之,在过去二十年中,中国与埃塞俄比亚两国之间建立了友好关系。两国之间的利益和政治使命形成了各种形式的协议。中国的直接投资和工业发展经验可为埃塞俄比亚的发展提供经验教训。同时中国对埃塞俄比亚的直接投资是宝贵的资金来源,对提高埃塞俄比亚政府收入至关重要。埃塞俄比亚采用中国的经验,将发展作为首要任务,消除饥饿,注重改革,通过政府调控弥补市场发展存在的问题。中国的参与促进了埃塞俄比亚当地企业的发展,有助于中国企业在埃塞俄比亚国内市场发展,为当地创造新的就业机会。同时中国的投资是埃塞俄比亚经济增长的支柱,它使埃塞俄比亚过去十年的经济增长率一直保持在两位数。中国的发展和工业化经验表明经济特区、变革性政策试验和融入全球价值链在经济发展可以发挥重要作用。本文研究表明,经济发展中的某些主要障碍需要采取政策措施来激励,这包括物流、地方监管、资源短缺、税收行政问题以及人力资本和生产力等相关问题。相关调查结果显示,通过私有化和现代化来提供服务解决问题以及获得外汇是埃塞俄比亚商业自由流通的主要困难,因此埃塞俄比亚国内应颁布相关政策缩小差距,将中国制造业与埃塞俄比亚当地经济发展结合起来,在原料制造商和供应商之间建立市场联系。最后,本文将清晰地展示中国政府参与投资对埃塞俄比亚经济的实际影响。这两个国家以及一系列组织都将从这一进程中受益。

关键词：对外直接投资行业经济特区经济

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Intestinal parasites infection and associated factors among sch.ol ch.ldren in Dagi primary sch.ol, Amh.ra National Regional State, Eth.opia

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h.alth 2013年第10期5卷 1697-1701页

作者： Mulat alamir Worku Awoke Amsalu Feleke College of Medicine and h.alth.Sciences Bahir Dar University Bahir Dar Ethiopia GAMBY College of Medical Sciences Bahir Dar Ethiopia Institute of Public h.alth College of Medicine and Health Sciences University of Gondar Gondar Ethiopia

Introduction: Intestinal parasitic infections are among th. most common communicable diseases worldwide, particularly in developing countries. Worldwide, about 3.5 billion people are affected, and 450 million are ill as a result of th.se infections, among wh.m, th. majority are ch.ldren. Th. objective of th.s study was to assess prevalence of intestinal parasites infection and associated risk factors among sch.ol ch.ldren in Dagi primary sch.ol, ANRS, Eth.opia. Meth.ds: Institutional-based cross-sectional study was conducted by involving 399 sch.ol ch.ldren from 24 September to 19 October, 2012. Structured questionnaires were used to identify environmental, socio-demograph.c and beh.vioral factors and stool specimens were collected and examined for parasites using direct smear and formal-eth.r concentration tech.ique. Data analysis was done by using SPSS version 15 statistical soft ware. Results: Eigh. species of intestinal parasites were identified with.an overall prevalence of 77.9%. Students were infected with.one or more intestinal parasites and th. predominant parasite was h.ok worm, 94 (23.6%) followed by G. lamblia 91 (22.8%), E. h.stoltica 86 (21.6%) and Strongyloides 6 (1.5%). Th. presence of mixed parasitic infection was 106 (34.1%), double and triple infections were 97 (91.5%) and 9 (8.5%) respectively. Intestinal parasitic infection was h.gh.r in ch.ldren wh.se fath.rs’ occupational status were farmers, wh. h.d unclean finger nails and wh. did not h.ve th. h.bit of wearing sh.es (p parasites infection was an important public h.alth.problem among Dagi primary sch.ol ch.ldren. Th.refore, th. local h.alth.office and oth.r governmental and non-governmental organizations need to give attention to th.s serious problem of intestinal parasitic infection of sch.ol ch.ldren.

关键词： Intestinal Parasitic Infections Amh.ra National Regional State Eth.opia

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