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Experimental and Numerical Study of the Key Non-Dimensional Geometrical Parameters on the Noise Level of Dry-Type Cast Resin Transformers

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Sound & Vibration 2019年第5期53卷 177-198页

作者： mahdi Soltanmohammadi Vahid Monfared Department of TechnicalOffice IranTransfo Co.ZanjanIran Young Researchers and EliteClub Zanjan BranchIslamicAzad UniversityZanjanIran

Dry-Type Cast Resin Distribution Transformers(CRT)is the secondgeneration of air-cooled distribution transformers where oil is replaced by resin for electrical *** transformers may installed indoor adjacent to or near residential areas since they are clean and safe comparing to the conventional ***,as it is obvious,noise discrepancy is intrinsically accompanied with all types of transformers and is inevitable for CRT transformers *** of noise level caused by such these transformers has biological and ergonomic *** it is known the core of transformers is the main source of the noise *** this paper,experimental and numerical investigation is implemented for a large number of fabricated CRT transformers in IT Co(Iran Transfo Company)to evaluate the effective geometrical parameters of the core on the overall sound level of *** Level of each sample is measured according to criteria of IEC60651 and is reported in units of Decibel(dB).Numerical simulation is done using noncommercial version of ANSYS Workbench software to extract first six natural frequencies and mode shapes of CRT cores which is reported in units of *** novel non-dimensional variables for geometry of the transformer core are *** experimental and numerical results show approximately similar response to these *** between natural frequencies and noise level is evaluated *** factor shows that there is a robust conjunction between first two natural frequencies and noise level of *** show that noise level decreases as the two first natural frequencies increases and vice versa,noise level increases as the two natural frequencies of the core *** the noise level decomposed to two parts.

关键词： Experimental FEM mean noise level CRT transformers IEC60651

Modeling of moisture loss kinetics and color changes in the surface of lemon slice during the combined infrared-vacuum drying

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Information Processing in Agriculture 2018年第4期5卷 516-523页

作者： Fakhreddin Salehi mahdi Kashaninejad Department of Food Industry Machines Bu-Ali Sina UniversityHamedanIran Faculty of Food Science Gorgan University of Agricultural Sciences and Natural ResourcesGorganIran

Color is one of the most important appearance attributes of food materials,since it influences consumer *** this study the effects of combined infrared-vacuum drying on the drying kinetics,moisture diffusivity,surface changes(shrinking)and color changes kinetics of lemon slices were *** the infrared lamp power and vacuum pressure influenced the drying time of lemon *** regression results showed that the quadratic model satisfactorily described the drying behavior of lemon slices with highest R value and lowest SE *** effective moisture diffusivity increased from 2.92×10^-10 and 1.58×10^-9m^2/s when the infrared lamp power was increased from 300 to *** colour parameters L^*(lightness),a^*(redness/greenness),b^*(yellowness/blueness),and DE(total colour difference)were used to estimate colour changes during drying.L^*,a^* and b^* values of dried lemon increased during *** rise in infrared power has a negative effect on the DE and with the increase of infrared radiation power it was *** kinetic models were used to fit the experimental data and the results revealed that the power model was the most suitable to describe the color change intensity(DE).

关键词： Colour parameters Image processing Infrared drying Kinetic Lemon

Design and optimization of nano-antenna for thermal ablation of liver cancer cells

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Chinese Physics B 2021年第4期30卷 574-585页

作者： Mohammad Javad Rabienejhad Azardokht Mazaheri mahdi Davoudi-Darareh Optics and Laser Science and Technology Research Center Malek Ashtar University of TechnologyShahinshahrIran Department of Physics University of IsfahanIran Faculty of Science Malek Ashtar University of TechnologyShahinshahrIran

One method of cancer therapy is to utilize nano-antenna for thermal *** this method,the electromagnetic waves emitted from the nano-antenna are absorbed by the tissue and lead to heating of cancer *** temperature of cancer cells reaches a threshold,they will begin to *** this purpose,an L-shaped frame nano-antenna(LSFNA) is designed to introduce into the biological ***,the radiation characteristics of the LSFNA such as near and far-field intensities,directivity,and sensitivity to its gap width are studied to the optimization of the *** bio-heat and Maxwell equations are solved using the finite element *** prevent damage to healthy tissues in this method,the antenna radiation must be completely controlled and performed ***,penetration depth,special absorption rate,temperature distribution,and the fraction of tissue necrosis are analyzed in the biological *** is why the design and optimization of the nano-antennas as a radiation source is ***,a pulsed source is used to excite the ***,focusing and efficiency of the nano-antenna radiation on the cancer cell is tuned using an adjustable liquid crystal *** focus of this lens is changing under an electric field applied to its surrounding cathode.

关键词： cancer therapy directivity far-field intensity hyperthermia liver cancer nano-antenna thermalablation tunable liquid crystal lens

Correlating thermal conductivity of pure hydrocarbons and aromatics via perceptron artificial neural network (PANN) method

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Chinese Journal of Chemical Engineering 2017年第5期25卷 547-554页

作者： Mostafa Lashkarbolooki Ali Zeinolabedini Hezave mahdi Bayat School of Chemical Engineering Babol University of Technology Islamic Azad University Dashtestan Branch Department of Chemical Engineering Faculty of EngineeringUniversity of Bojnord

Accurate estimation of liquid thermal conductivity is highly necessary to appropriately design equipments in different industries. Respect to this necessity, in the current investigation a feed-forward artificial neural network(ANN) model is examined to correlate the liquid thermal conductivity of normal and aromatic hydrocarbons at the temperatures range of 257–338 K and atmospheric pressure. For this purpose, 956 experimental thermal conductivities for normal and aromatic hydrocarbons are collected from different previously published *** the modeling stage, to discriminate different substances, critical temperature(Tc), critical pressure(Pc)and acentric factor(ω) are utilized as the network inputs besides the temperature. During the examination, effects of different transfer functions and number of neurons in hidden layer are investigated to find the optimum network architecture. Besides, statistical error analysis considering the results obtained from available correlations and group contribution methods and proposed neural network is performed to reliably check the feasibility and accuracy of the proposed method. Respect to the obtained results, it can be concluded that the proposed neural network consisted of three layers namely, input, hidden and output layers with 22 neurons in hidden layer was the optimum ANN model. Generally, the proposed model enables to correlate the thermal conductivity of normal and aromatic hydrocarbons with absolute average relative deviation percent(AARD), mean square error(MSE), and correlation coefficient(R^2) of lower than 0.2%, 1.05 × 10^(-7) and 0.9994, respectively.

关键词： Thermal conductivity Artificial neural network Critical properties Hydrocarbons Aromatics

Predicting seismic permanent displacement of soil walls under surcharge based on limit analysis approach

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 747-759页

作者： Mohammad mahdi Aminpour Mohammad Maleki Ali Ghanbari Faculty of Engineering Bu-Ali Sina University Faculty of Engineering Kharazmi University

Seismic permanent displacement of the soil walls plays an important role in design of these structures. Due to the increase in growth of urban areas and the limitations in use of flat grounds, many structures are built near slopes and retaining walls. During earthquakes, these structures can apply an additional surcharge on the wall. The intensity and location of the surcharge is of considerable importance on the seismic displacements of the soil wall. In this study, by using the limit analysis and upper bound theorem, seismic permanent displacement of the soil wall under surcharge has been analyzed. Thus, a formulation is presented for calculating the yield acceleration and seismic displacement for different surcharge conditions. The effect of seismic acceleration, surcharge intensity, its location and soil properties is investigated. A parameter called the ＂displacement coefficient＂ is proposed, and is a potential modification for Newmark’s sliding-block method.

关键词： limit analysis surcharge soil wall seismic displacement yield acceleration

Numerical investigation of particle separation in Y-shaped bifurcating microchannels

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Particuology 2021年第3期19卷 142-151页

作者： Mahya Meyari Zeinab Salehi Reza Zarghami mahdi Saeedipour School of Chemical Engineering College of EngineeringUniversity of TehranTehranIran Department of Particulate Flow Modelling Johannes Kepler UniversityLinzAustria

In this study the Zweifach-Fung effect is investigated in a Y-shaped bifurcation when the clearance between the rigid spherical particle and the walls is small compared to both channel’s and particle’s ***-and two-particle systems are studied using resolved computational fluid dynamics coupled to discrete element method to obtain a two-dimensional map of the initially positioned particles that would enter each child *** all cases,the path selection of the sphere depends on its two-dimensional positioning far from the bifurcation region in the parent *** the flow rate ratio or decreasing the Reynolds number intensifies the Zweifach-Fung bifurcation effect in a single-particle ***,in two-particle systems where non-contact particle-particle interaction is present,decreasing the particle-to-particle distance reduces the bifurcation effect,while changing the Reynolds number has the same influence as in the single-particle *** results provide insight for optimizing the flow characteristics in bifurcating microchannels to separate the suspended particles.

关键词： Zweifach-Fung effect Bifurcation CFD-DEM MicrOfluidics Particle separation

Dynamic Modeling and Closed-loop Control of Hybrid Grid-connected Renewable Energy System with Multi-input Multi-output Controller

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Journal of Modern Power Systems and Clean Energy 2021年第1期9卷 94-103页

作者： mahdi Salimi Fereshteh Radmand Mansour Hosseini Firouz the Department of Electrical Engineering Ardabil BranchIslamic Azad UniversityArdabilIran

In this study, a novel approach for dynamic modeling and closed-loop control of hybrid grid-connected renewable energy system with multi-input multi-output(MIMO) controller is proposed. The studied converter includes two parallel DC-DC boost converters, which are connected into the power grid through a single-phase H-bridge inverter. The proposed MIMO controller is developed for maximum power point tracking of photovoltaic(PV)/fuel-cell(FC) input power sources and output power control of the grid-connected DC-AC inverter. Considering circuit topology of the system, a unique MIMO model is proposed for the analysis of the entire system. A unique model of the system includes all of the circuit state variables in DCDC and DC-AC converters. In fact, from the viewpoint of closed-loop controller design, the hybrid grid-connected energy system is an MIMO system. The control inputs of the system are duty cycles of the DC-DC boost converters and the amplitude modulation index of DC-AC inverters. Furthermore, the control outputs are the output power of the PV/FC input power sources as well as AC power injected into the power grid. After the development of the unique model for the entire system, a decoupling network is introduced for system input-output linearization due to inherent connection of the control outputs with all of the system inputs. Considering the decoupled model and small signal linearization, the required linear controllers are designed to adjust the outputs. Finally, to evaluate the accuracy and effectiveness of the designed controllers, the PV/FC based grid-connected system is simulated using the MATLAB/Simulink toolbox.

关键词： Multi-input multi-output(MIMO)converter maximum power point tracking grid-connected inverter conversion function matrix

Using an Inhibitor to Prevent Plasticizer Migration from Polyurethane Matrix to EPDM Based Substrate

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Chinese Journal of Polymer Science 2019年第7期37卷 681-686页

作者： Hadi Rezaei-Vahidian Tohid Farajpour mahdi Abdollahi Space Transportation Research Institute Iranian Space Research CenterTehranIran Polymer Reaction Engineering Department Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran

The loss of adhesion between the propellant and insulator is one of the most important problems in solid propellant motors due to migration of plasticizer to interface of propellant and insulator. In this work, the polyurethane (PU) binder containing DOP plasticizer was used as a polymeric matrix and β-cyclodextrin (β-CD) was applied as inhibitor agent to prevent plasticizer migration from the PU matrix into the ethylene propylene diene monomer (EPDM) substrate. To increase the compatibility of β-CD and PU matrix, a derivative of β-CD has been synthesized using toluene diisocyanate (β-CD-TDI). The synthesized derivative was characterized by MALDI-MS and FTIR-ATR analyses. FTIR-ATR results confirmed the formation of bonding between β-CD and the polymeric network while the MALDIMS results showed that the synthesized derivative contained two β-CD and 7 TDI molecules bonded to β-CD. Investigation of the mechanical properties of PU modified by β-CD-TDI showed a decrease in tensile strength and an increase in elongation at break with increasing β-CD-TDI content. DMTA results showed a decrement in crosslinking density by increasing the β-CD-TDI content. Also, to investigate plasticizer migration, extraction of the DOP plasticizer from samples was performed using dichloromethane solvent and its concentration was measured by gas chromatography. The results of migration evaluation after four months showed that using β-CD as an inhibitor agent in the PU binder could prevent the migration of plasticizer to EPDM substrate.

关键词： Plasticizer migration β-Cyclodextrin Polyurethane

LMI Based Synchronization Control of Nonlinear Affine Fractional Order Chaotic Systems Considering Input Constraint

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Journal of Systems Science and Systems Engineering 2023年第6期32卷 643-655页

作者： Ali Soleimanizadeh Mohammad Ali Nekoui mahdi Aliyari Shoorehdeli Department of Electrical Engineering Islamic Azad University South Tehran BranchTehranIran Department of Electrical Engineering K N Toosi University of TechnologyTehranIran

The current paper deals with synchronization problem among chaotic nonlinear fractional order systems considering input saturation *** develop the idea,at first a generalized sector condition and a memory-less nonlinear function are employed to deal with the saturation *** a new state feedback controller is designed to achieve synchronization in master-slave chaotic fractional order nonlinear systems with input *** the state feedback controller,the asymptotic stability of whole dynamic error model between master and slave is *** stability of the closed-loop system is guaranteed using Lyapunov theory and sufficient stability conditions are formulated in terms of caputo fractional derivative of a quadratic Lyapunov function and Linear Matrix Inequalities(LMI).Finally,to verify the effectiveness of the proposed control scheme,some simulation results are employed to show the effectiveness of the proposed methodology.

关键词： Input Affine system chaos systems input saturation nonlinear fractional order feedback controller synchronization