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Journal of Central South University 2017年第9期24卷 2035-2048页

作者： mohammadi mohammad Department of Electrical Engineering Borujerd BranchIslamic Azad UniversityBorujerdIran

Due to development of distribution systems and increase in electricity demand,the use of capacitor banks *** the other point of view,nonlinear loads generate and inject considerable harmonic currents into power *** this condition if capacitor banks are not properly selected and placed in the power system,they could amplify and propagate these harmonics and deteriorate power quality to unacceptable *** attention of disadvantages of passive filters,such as occurring resonance,nowadays the usage of this type of harmonic compensator is *** the other side,one of parallel multi-function compensating devices which are recently used in distribution system to mitigate voltage sag and harmonic distortion,performs power factor correction,and improves the overall power quality as active power conditioner(APC).Therefore,the utilization of APC in harmonic distorted system can affect and change the optimal location and size of shunt capacitor bank under harmonic distortion *** paper presents an optimization algorithm for improvement of power quality using simultaneous optimal placement and sizing of APC and shunt capacitor banks in radial distribution networks in the presence of voltage and current *** algorithm is based on particle swarm optimization(PSO).The objective function includes the cost of power losses,energy losses and those of the capacitor banks and APCs.

关键词： shunt capacitor banks active power conditioner multi-objective function particle swarm optimization (PSO) harmonic distorted distribution system

IMC based robust PID controller tuning for disturbance rejection

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Journal of Central South University 2016年第3期23卷 581-597页

作者： mohammad Shamsuzzoha Department of Chemical Engineering King Fahd University of Petroleum and Minerals

It is well-known that the IMC-PID controller tuning gives fast and improved set point response but slow disturbance rejection. A modification has been proposed in IMC-PID tuning rule for the improved disturbance rejection. For the modified IMC-PID tuning rule, a method has been developed to obtain the IMC-PID setting in closed-loop mode without acquiring detailed information of the process. The proposed method is based on the closed-loop step set point experiment using a proportional only controller with gain K_(c0). It is the direct approach to find the PID controller setting similar to classical Ziegler-Nichols closed-loop method. Based on simulations of a wide range of first-order with delay processes, a simple correlation has been derived to obtain the modified IMC-PID controller settings from closed-loop experiment. In this method, controller gain is a function of the overshoot obtained in the closed loop set point experiment. The integral and derivative time is mainly a function of the time to reach the first peak(overshoot). Simulation has been conducted for the broad class of processes and the controllers were tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison. The PID controller settings obtained in the proposed tuning method show better performance and robustness with other two-step tuning methods for the broad class of processes. It has also been applied to temperature control loop in distillation column model. The result has been compared to the open loop tuning method where it gives robust and fast response.

关键词： PI/PID controller step test closed-loop response IMC-PID overshoot

Efficient Wind Turbine Generation Planning for Decreasing Distribution System Company Payments in Real Applications

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 81-90页

作者： mohammad Hasan Hemmatpour mohammad Hossein Rezaeian Koochi Electrical Engineering Department Faculty of EngineeringJahrom UniversityJahromIran Department of Electrical Engineering Shahid Bahonar University of KermanKermanIran

Wind energy has posed new challenges in both transmission and distribution systems owing to its uncertain nature. The effect of wind turbines (WTs) on the actual payments charged by upstream networks to distribution system companies (DISCOs) is one challenge. Moreover, when the grid-connected inverters of WT operate in the lead or lag modes, WTs absorb or inject reactive power from the system. This paper proposes an approach to assess the importance of operation modes of WTs to minimize the costs by DISCOs in the presence of system uncertainties. Accordingly, an optimization problem is formulated to minimize the costs to DISCO by determining the optimal locations and sizes of WTs in optimally reconfigured distribution systems. In addition, an improved vector-based swarm optimization (IVBSO) algorithm is proposed because it is highly suitable for vector-based problems. Two distribution systems are used in the simulations to evaluate the proposed algorithm. Firstly, the capabilities of the IVBSO algorithm to determine better solutions over other heuristic algorithms are confirmed using the IEEE 33-bus test system. Secondly, the BijanAbad distribution system (BDS) is used to demonstrate the effectiveness of the proposed optimization problem. Accordingly, the distribution system model, cumulative distribution function of wind speed, and load profile are all extracted from the actual data of the BijanAbad region. Finally, the optimization problem is applied to BDS in both the lead and lag modes of WTs. Results indicate that the total costs of DISCO are lower when WTs operate in the lag mode than in the lead mode.

关键词： Distribution system companies(DISCOs) improved vector-based swarm optimization(IVBSO) reconfiguration wind turbine operation mode

Effect of volume-contraction on incipient fluidization of binary-solid mixtures

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Particuology 2011年第2期9卷 101-106页

作者： mohammad Asif Chemical Engineering Department King Saud University

Towards the development of a predictive model for computing the minimum fluidization velocity, the volume-contraction phenomenon arising from the mixing of unequal solid species is accounted for in the prediction of the bed void fraction of binary-solid mixtures at the incipient fluidization conditions. Com- parison with experimental data obtained from the literature clearly shows that significantly improved predictions are obtained except for cases where the stratification pattern whether arising from the slow defluidization or the difference in the densities of the two species affects the mixing of the constituent species.

关键词： Binary solid mixture Bed void fraction Volume-contraction Minimum fluidization velocity

Approximation of structural damping and input excitation force

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Frontiers of Structural and Civil Engineering 2017年第2期11卷 244-254页

作者： mohammad SALAVATI Institute of Structural Mechanics Faculty of Civil Engineering Bauhaus University Weimar Weimar 99423 Germany

Structural dynamic characteristics are the most significant parameters that play a decisive role in structural damage assessment. The more sensitive parameter to the damage is the damping behavior of the structure. The complexity of structural damping mechanisms has made this parameter to be one of the ongoing research topics. Despite all the difficulties in the modeling of damping, there are some approaches like as linear and nonlinear models which are described as the energy dissipation throughout viscous, material or structural hysteretic and frictional damping mechanisms. In the presence of a mathematical model of the damping mechanisms, it is possible to estimate the damping ratio from the theoretical comparison of the damped and un-damped systems. On the other hand, solving the inverse problem of the input force estimation and its distribution to each SDOFs, from the measured structural responses plays an important role in structural identification process. In this paper model-based damping approximation method and a modelless structural input estimation are considered. The effectiveness of proposed methods has been carded out through analytical and numerical simulation of the lumped mass system and the results are compared with reference data. Consequently, high convergence of the comparison results illustrates the satisfactory of proposed approximation methods.

关键词： structural modal parameters damping identification method input excitation force identification Inverse problem

Predicting minimum fluidization velocities of multi-component solid mixtures

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Particuology 2013年第3期11卷 309-316页

作者： mohammad Asif Chemical Engineering Department King Saud University

Employing well-established mixing rules for mean properties, appropriate expressions are derived for predicting minimum fluidization velocities of multi-component solid mixtures in terms of mono- component values for the velocity and the bed voidage at incipient fluidization. Based on flow regime and the mixing level of constituent species, it is found that these relationships differ significantly from each other, whether related to size-different or density-different mixtures. For mixed beds of size-different mixtures, the effect of volume contraction is accounted for by the mean voidage term, which is absent for segregated beds. Incorporating the volume-change of mixing leads to values of the mixture minimum fluidization velocities even lower than corresponding values for segregated bed, thus conforming to the trend reported in the literature. Size-different mixtures exhibit flow regime dependence irrespective of whether the bed is mixed or segregated. On the other hand, the mixing of constituent species does not affect the minimum fiuidization velocity of density-different mixtures, as the difference in the expres- sions for a segregated and a mixed system is rather inconsequential. Comparison with experimental data available in the literature is made to test the efficacy of the minimum fluidization velocity expressions derived here.

关键词： Minimum fluidization velocity Multi-component solid mixtures Flow regime Bed void fraction Volume-change of mixing

Electronic and mechanical responses of two-dimensional HfS2,HfSe2,ZrS2,and ZrSe2 from first-principles

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 486-494页

作者： mohammad SALAVATI Institute of Structural Mechanics Bauhaus-Universitat WeimarD-99423 WeimarGermany

During the last decade, numerous high-quality two-dimensional (2D) materials with semiconducting electronic character have been synthesized. Recent experimental study (Sci. Adv. 2017;3: el700481) nevertheless confirmed that 2D ZrSe2 and HfSe2 are among the best candidates to replace the silicon in nanoelectronics owing to their moderate band-gap. We accordingly conducted first-principles calculations to explore the mechanical and electronic responses of not only ZrSe2 and HfSe2, but also ZrS? and HfS? in their single-layer and free-standing form. We particularly studied the possibility of engineering of the electronic properties of these attractive 2D materials using the biaxial or uniaxial tensile loadings. The comprehensive insight provided concerning the intrinsic properties of HfS2, HfSe2, ZrS2, and ZrSc? can be usefiil for their future applications in nanodevices.

关键词： 2D materials mechanical electronic DFT

A Simplified Model, Dynamic Analysis and Force Estimation for a Large-scale Orinthopter in Forward Flight Based on Flight Data

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Journal of Bionic Engineering 2020年第5期17卷 989-1008页

作者： mohammad Ali Amini Moosa Ayati mohammad Mahjoob School of Mechanical Engineering College of EngineeringUniversity of TehranNorth Kargar StreetTehranIran

Similarities and differences of a large-scale flapping-wing robot with fixed-wing UAVs in equations of motion,trim curves,and aerodynamic forces in forward flight are discussed in this paper and a simplified model for flapping flight is *** to the high Wing to Total Weight(WTW)ratio of large-scale omithopters,simple rigid body dynamics is not accurate enough for flight dynamics *** the other hand,the multi-body dynamics associated with flapping gives little insight into the behavior of the resulting model due to complexity of *** is also difficult to design proper controllers for such complicated *** this paper,the effects of different terms of multi-body equations of ornithopter on the estimated aerodynamic forces are studied via experimental flight data.A simpler but yet accurate set of equations is obtained by removing less effective terms from original *** presented model is in the form of normal aircraft equations plus some additional terms which can be used in different control and estimation *** addition,trim conditions of forward flight are extracted using several flight tests,and corresponding periodic behavior of states and forces are *** studies are applicable for identifying time-periodic models.

关键词： flapping wing robot bionic robot ornithopter trim condition analysis low-order modeling aerodynamic force estimation

Determination of hemoglobin adduct of a musk xylene metabolite in trout as biomarker of exposure by gas chromatography mass spectrometry

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Journal of Environmental Sciences 2005年第6期17卷 989-992页

作者： mohammad Abdul KARIM mohammad Rezaul Department of Chemistry and Biochemistry Baylor University P.O. Box 97348 Waco TX 76798-7348 USADepartment of Biochemistry and Molecular Biology University of Rajshahi Rajshahi 6205 Bangladesh

Musk xylene（MX） is frequently used as fragrances in formulation of personal care products. Quantification of a bound 4-amino- MX（4-AMX） as cysteine adducts in trout hemoglobin（Hb） was made by gas chromatography-ion trap-mass spectrometry（GC/MS）. The Hb samples were collected from trout after 24 h exposure to MX at 10μg/g, and or menhaden oil（control）. The formation of cysteine-Hb adduct was observed from nitroso derivative of MX, released by alkaline hydrolysis. The released 4-AMX metabolite was extracted in n- hexane. The extract was then reduced by evaporation, and analyzed by GC/MS. When similar agreement of mass spectral features and retention time of 4-AMX were obtained in both standard and sample solutions, the presence of 4-AMX metabolite in the Hb was confirmed. The concentration of 4-AMX was found to be 3.1 × 10^-6 6.9 × 10^-6 mg/g in the Hb solution. Quantitation was made based on an internal standard, a calibration plot, and response factor. In the non-hydrolyzed and laboratory blank extracts, the 4-AMX metabolite was not detected. Additionally, coeluting and interfefing ions were observed in the biological samples.

关键词： biomarkers musk xylene metabolite Hb adducts fish exposure

Experimental investigation of different brines imbibition influences on co-and counter-current oil flows in carbonate reservoirs

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Chinese Journal of Chemical Engineering 2021年第5期34卷 17-29页

作者： Pouyan Ahmadi mohammad Reza Aghajanzadeh Masoud Riazi mohammad Reza Malayeri mohammad Sharifi Enhanced Oil Recovery(EOR)Research Centre IOR/EOR Research InstituteShiraz UniversityShirazIran Helmholtz Centre for Environmental Research-UFZ LeipzigGermany Department of Petroleum Engineering Amirkabir University of TechnologyTehranIran Institut für Verfahrenstechnik und Umwelttechnik Technische Universität DresdenGermany

Imbibition of water,as wetting phase in oil-wet fractured carbonate reservoirs,plays a key role in fluid flow between matrix and fracture *** type of injected seawater and its chemistry would profoundly influence the imbibition *** this study,the impact of smart water(a brine that its ions have been adjusted to facilitate oil recovery)and low salinity water on co-and counter-current imbibition processes for oil-wet carbonate cores has been experimentally *** results show an increase of about 10% in oil recovery for co-and counter-currents for smart seawater imbibition compared to that of low salinity *** addition,as a result of the influence of co-and counter-current on each other,by co-current removal from one core face,the countercurrent in the other face would be intensified by as much as about 75%.A close examination of different lengths(5,7 and 9 cm)of carbonate cores with the same permeability revealed that by decreasing porous medium length,the amount of counter-current producing oil would be decreased so that in the 5 cm core,counter current oil production will not *** similar core lengths by increasing permeability,the share of counter current flow would be decreased approximately 18% since the capillary pressure could not overcome non-wetting phase viscous *** the role of matrix length along with a modified brine(which is designed according to the matrix mixture)strengthen the relevant mechanisms to have more oil production so that the higher thickness of matrix causes the higher amount of co-current oil producing and consequently more total recovery.

关键词： Smart water Co-current Counter current Wettability alteration Oil recovery