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A Nonlinear Coordinated Approach to Enhance the Transient Stability of Wind Energy-Based Power Systems

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 1087-1097页

作者： mohammad Javad Morshed the Department of Electrical and Computer Engineering University of Louisiana at LafayetteLafayetteLA 70504 USA

This paper proposes a novel framework that enables the simultaneous coordination of the controllers of doubly fed induction generators(DFIGs) and synchronous generators(SGs).The proposed coordination approach is based on the zero dynamics method aims at enhancing the transient stability of multi-machine power systems under a wide range of operating conditions. The proposed approach was implemented to the IEEE39-bus power systems. Transient stability margin measured in terms of critical clearing time along with eigenvalue analysis and time domain simulations were considered in the performance assessment. The obtained results were also compared to those achieved using a conventional power system stabilizer/power oscillation(PSS/POD) technique and the interconnection and damping assignment passivity-based controller(IDA-PBC). The performance analysis confirmed the ability of the proposed approach to enhance damping and improve system’s transient stability margin under a wide range of operating conditions.

关键词： Doubly fed induction generator(DFIG) excitation controller multi-machine power system synchronous generator(SG) transient stability zero dynamics

A novel technology for control of variable speed pumped storage power plant

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Journal of Central South University 2016年第8期23卷 2008-2023页

作者： Seyed mohammad Hassan Hosseini mohammad Reza Semsar Department of Electrical Engineering Islamic Azad University

Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.

关键词： direct torque and flux control(DTFC) two-level & three-level voltage source converter(2LVSC&3LVSC) variable speed pumped storage power plant(VSPSP)

A new robust fuzzy method for unmanned flying vehicle control

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Journal of Central South University 2015年第6期22卷 2166-2182页

作者： Mojtaba Mirzaei mohammad Eghtesad mohammad Mahdi Alishahi Department of Mechanical Engineering Shiraz University

A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. The proposed control system combined great advantages of generalized indirect adaptive sliding mode control(IASMC) and fuzzy control for the UFVs. An on-line adaptive tuning algorithm based on Lyapunov function and Barbalat lemma was designed, thus the stability of the system can be guaranteed. The chattering phenomenon in the sliding mode control was reduced and the steady error was also alleviated. The numerical results, for an underactuated quadcopter and a high speed underwater vehicle as case studies, indicate that the presented adaptive design of fuzzy sliding mode controller performs robustly in the presence of sensor noise and external disturbances. In addition, online unknown parameter estimation of the UFVs, such as ground effect and planing force especially in the cases with the Gaussian sensor noise with zero mean and standard deviation of 0.5 m and 0.1 rad and external disturbances with amplitude of 0.1 m/s2 and frequency of 0.2 Hz, is one of the advantages of this method. These estimated parameters are then used in the controller to improve the trajectory tracking performance.

关键词： adaptive fuzzy sliding-mode control unmanned flying vehicle control underactuated system Lyapunov stability high speed underwater vehicle

Risk-based probabilistic thermal-stress analysis of concrete arch dams

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1007-1019页

作者： Narjes SOLTANI mohammad ALEMBAGHERI mohammad Houshmand KHANEGHAHI Department of Civil and Environmental Engineering Tarbiat Modares UniversityTehran ***Iran Department of Civil Engineering Shahid Beheshti UniversityTehran ***Iran

The probabilistic risk of arch dam failure under thermal loading is studied. The incorporated uncertainties, which are defined as random variables, are associated with the most affecting structural (material) properties o f concrete and thermal loading conditions. Karaj arch dam is selected as case study. The dam is numerically modeled along with its foundation in three-dimensional space;the temperature and thermal stress distribution is investigated during the operating phase. The deterministic thermal finite element analysis o f the dam is combined with the structural reliability methods in order to obtain thermal response predictions, and estimate the probability o f failure in the risk analysis context. The tensile overstressing failure mode is considered for the reliability analysis. The thermal loading includes ambient air and reservoir temperature variations. The effect o f solar radiation is considered by an increase in the ambient temperatures. Three reliability methods are employed: the first-order second-moment method, the first-order reliability method, and the Monte-Carlo simulation with Latin Hypercube sampling. The estimated failure probabilities are discussed and the sensitivity o f random variables is investigated. Although most of the studies in this line o f research are used only for academic purposes, the results of this investigation can be used for both academic and engineering purposes.

关键词： arch dams probabilistic analysis thermal stress sensitivity reliability

Effects of floods on macroinvertebrate communities in the Zarin Gol River of northern Iran: implications for water quality monitoring and biological assessment

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Ecological Processes 2021年第1期10卷 608-618页

作者： mohammad Gholizadeh Department of Fisheries Faculty of Agriculture and Natural ResourcesGonbad Kavous UniversityBasirat BlvdShahid Fallshi StrGonbad KavousGolestan Province P.O.163Iran

Background:The timing,magnitude,and duration of extreme hydrological disasters have the potential to threaten the species diversity and river *** August 8,2014,and August 19,2017,disastrous floods struck mountainous regions of Iran’s Zarin Gol River *** communities were studied at seven upstreams prior to the floods in June 2014 and 2017 and after the floods in September 2014 and 2017 and 9 months after the second flood in June *** effects of floods on macroinvertebrate communities,recovery rate of macroinvertebrate community resilience and influencing factors were ***:Despite the fact that extreme floods were the only reason of the disruption,the effects of biological water quality assessment metrics after the disaster were comparable to those of heavily polluted *** indicators revealed that the communities were unaffected prior to the floods,and the water quality remained within acceptable *** the disasters,the density of macroinvertebrates declined,and biological indicators demonstrated the severe depletion of water *** indicators(species richness,percent model affinity(PMA),and Ephemeroptera,Plecoptera,and Trichoptera(EPT)richness)rebounded after 9 months(June 2018),demonstrating that Zarin Gol River’s macroinvertebrate communities could recover even after the severe impact of the *** a result,macroinvertebrate samples taken from flood-affected areas revealed that extreme flooding,rather than a decrease in water quality,causes a loss of diversity and ***:Because of shifts in hydrological regimes in streams around the world,understanding the short-term impacts of strong flooding and the comparatively quick recovery of macroinvertebrate ecosystems has important consequences for bio-assessment programs after severe floods.

关键词： Macroinvertebrate Climate change Bio-assessment Hydrology

Effect of graphene oxide and reduced graphene oxide nanosheets on the microstructure and mechanical properties of mild steel jointing by flux-cored arc welding

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 505-514页

作者： mohammad Khosravi mohammad Mansouri Ali Gholami Yadollah Yaghoubinezhad Department of Mechanical Engineering Birjand University of Technology BirjandP.O.Box 97175-569235Iran Department of Materials Engineering Birjand University of Technology BirjandP.O.Box 97175-569315Iran

The effect of graphene oxide(GO)and reduced graphene oxide(RGO)nanosheets on the microstructure and mechanical properties of welded joints of mild steel was evaluated by flux-cored arc *** was synthesized by the Hummer’s method and was reduced under hydrothermal conditions at a pressure of 1.1 MPa at 180°C for 12 h.1,3,and 10 mg/mL paste fillers were used in GO and RGO,and applied to the weld *** results clearly showed that by increasing the concentration of RGO up to 10 mg/mL,the tensile strength and hardness of the weld metal were improved by approximately 20.5%and 38.4%,respectively,because the coarse grains were changed into fine *** domain of the nanosheets cluster was 19.85×10^?9 ***,the RGO nanosheets contributed to modifying the mechanical properties of the welded steel,likely due to dislocation pinning.

关键词： graphene oxide reduced graphene oxide flux-cored arc welding steel mechanical properties

Interactive Effect of GA_3 ,N and P Ameliorate Growth, Seed and Fibre Yield by Enhancing Photosynthetic Capacity and Carbonic Anhydrase Activity of Linseed: A Dual Purpose Crop

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Journal of Integrative Agriculture 2013年第7期12卷 1183-1194页

作者： mohammad N Khan Firoz mohammad Department of Biology Faculty of Science University of Tabuk Plant Physiology Section Department of Botany Aligarh Muslim University

Linseed （Linum usitatissimum L.） is an important dual-purpose, industrial crop. Its seeds are used for the extraction of oil and stem for fibres. However, the production of linseed is not going parallel with the increasing demand of its products. The present work was carried out with an aim to find out whether exogenous application of gibberellic acid （GA3） with or without graded levels of nitrogen （N） and phosphorus （P） could improve the performance of three linseed genotypes Parvati, Shekhar and Shubhra together with minimizing the costly fertilizer input and losses. Four combinations of N and P, viz., 0 mg N＋0 mg P kg-1 soil （N0P0）, N13.4 P4.46 , N26.8P8.94 and N40.2P13.4 were constituted. Half dose of each combination was applied basally at the time of sowing and remaining half dose was given at 40 d after sowing （DAS） as foliar spray along with 10-6 mol L-1 GA3 . Prior to sowing, the seeds of each linseed genotype were grouped in to two, one group of seeds was soaked in 0 mol L-1 GA3 （control） and the other group was soaked in 10-6 M GA3 solution, each for 8 hours. Treatments were comprised of （i） 0 mol L-1 GA3＋N0P0 （T0 , control）, （ii） 10-6 mol L-1 GA3 ＋ N13.4P4.46 （T1）, （iii） 10-6 mol L-1 GA 3 ＋N 26.8 P 8.94 （T2） and （iv） 10-6 mol L-1 GA3＋N40.2P13.4 （T3）. The crop performance was assessed in terms of growth, physiological and biochemical parameters at 60 and 75 DAS and yield attributes at harvest （175 DAS）. The results showed a parallel increase in most of the parameters with increasing levels of N and P. However, application of 10-6 mol L-1 GA3 in association with N26.8P8.94 proved best, it enhanced seed yield, oil yield and fibre yield by 83.3, 97.3 and 78.7%, respectively accompanied with increase in net photosynthetic rate, carbonic anhydrase activity and dry matter accumulation. Among the genotypes tested, Shubhra performed best, while Parvati the least for most of the parameters studied. Thus, combined application of 10-6 mol L-1 GA3 plus N26.8P8.94 pro

关键词： gibberellin photosynthesis crbonic anhydrase linseed

Modification of rock mass rating system:Interbedding of strong and weak rock layers

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第6期9卷 1165-1170页

作者： mohammad mohammadi mohammad Farouq Hossaini The Alborz Tunnel Site Geodata EngineeringMazandaran ProvinceIran Faculty of Mining Engineering Engineering University CollegeUniversity of TehranTehranIran

Rock mass classification systems are the very important part for underground projects and rock mass rating(RMR) is one of the most commonly applied classification systems in numerous civil and mining projects. The type of rock mass consisting of an interbedding of strong and weak layers poses difficulties and uncertainties for determining the RMR. For this, the present paper uses the concept of rock bolt supporting factor(RSF) for modification of RMR system to be used in such rock mass types. The proposed method also demonstrates the importance of rock bolting practice in such rock masses. The geological parameters of the Shemshak Formation of the Alborz Tunnel in Iran are used as case examples for development of the theoretical approach.

关键词： Rock mass rating(RMR) Strong and weak rock layers Interbedding Rock bolt supporting factor(RSF) Alborz tunnel

Fuzzy TOPSIS method to primary crusher selection for Golegohar Iron Mine(Iran)

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Journal of Central South University 2014年第11期21卷 4352-4359页

作者： mohammad Javad Rahimdel mohammad Karamoozian Department of Mining Engineering Sahand University of TechnologyTabriz 51335-1996 Iran Faculty of Mining Engineering Petroleum and Geophysics Shahrood University of TechnologyShahrood 361999 5161 Iran

Selection of the crusher required a great deal of design regarding to the mine planning. Selection of suitable primary crusher from all of available primary crushers is a multi-criterion decision making(MCDM) problem. The present work explores the use of technique for order performance by similarity to ideal solution(TOPSIS) with fuzzy set theory to select best primary crusher for Golegohar Iron Mine in Iran. Gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impact crusher, hammer mill and feeder breaker crushers have been considered as alternatives. Also, the capacity, feed size, product size, rock compressive strength, abrasion index and application of primary crusher for mobile plants were considered as criteria for solution of this MCDM problem. To determine the order of the alternatives, closeness coefficient is defined by calculating the distances to the fuzzy positive ideal solution(FPIS) and fuzzy negative ideal solution(FNIS). Results of our work based on fuzzy TOPSIS method show that the gyratory is the best primary crusher for the studied mine.

关键词： primary crusher multi-criterion decision making(MCDM) technique for order performance by similarity to ideal solution fuzzy set theory Golegohar Iron Mine gyratory crusher