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Seismic fragility analysis of bridges by relevance vector machine based demand prediction model

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Earthquake Engineering and Engineering Vibration 2022年第1期21卷 253-268页

作者： Swarup ghosh Subrata Chakraborty Department of Civil Engineering Indian Institute of Engineering Science and TechnologyShibpurHowrah 711103India

A relevance vector machine(RVM)based demand prediction model is explored for efficient seismic fragility analysis(SFA)of a bridge *** proposed RVM model integrates both record-to-record variations of ground motions and uncertainties of parameters characterizing the bridge *** efficient fragility computation,ground motion intensity is included as an added dimension to the demand prediction *** incorporate different sources of uncertainty,random realizations of different structural parameters are generated using Latin hypercube sampling *** fragility,along with its dispersions,is estimated based on the log-normal fragility model for different critical components of a *** effectiveness of the proposed RVM model-based SFA of a bridge structure is elucidated numerically by comparing it with fragility results obtained by the commonly used SFA approaches,while considering the most accurate direct Monte Carlo simulation-based fragility estimates as the *** proposed RVM model provides a more accurate estimate of fragility than conventional approaches,with significantly less computational *** addition,the proposed model provides a measure of uncertainty in fragility estimates by constructing confidence intervals for the fragility curves.

关键词： bridge structure seismic fragility analysis seismic demand model relevance vector machine

Performance Optimization of Microstrip Antenna with Different Slot Configurations and Various Dielectric Materials

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Journal of Electronic Science and Technology 2018年第4期16卷 379-384页

作者： Soumendu ghosh Abhijit ghosh Indranath Sarkar Department of Electronics and Communication Engineering JIS College of Engineering( India) Department of Radio Plysics and Electronics University of Calcutta

The probe-fed patch antennas were proposed by changing the parameters such as dielectric materials and dimensions of patch for detail investigation of changes in output characteristics. Four rectangular slots were introduced separately for optimizing the antenna design and characteristics. This study illustrated the changes of output characteristics of an antenna with respect to the number of introduced slots on the radiating patch in addition to the effect of various dielectric materials on antenna performances. The antenna performances were analyzed by plotting the observation of various dielectric materials. The changes of antenna characteristics were also observed by introducing four numbers of slots on each edge of the patch to improve radiation characteristics with a wider impedance bandwidth.

关键词： Microstrip antenna probe-fed slot-antenna wireless communications

Dielectric Relaxations in Ferroelectric Copolymer VDF(73)/TrFE(27)

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Journal of Materials Science & Technology 1995年第1期11卷 31-37页

作者： ZHANG, XY FURUKAWA, tk SCI UNIV TOKYO DEPT CHEMTOKYO 162JAPAN

The characteristics of molecular motion of ferroelectric copolymer VDF(73)/TrFE(27) have been investigated by means of dielectric relaxation. With the rise in crystallinity, the Curie point decreases and the dielectric constant increases in the region of ferroelectric-to-paraelectric phase transition. The frequency spectra of the copolymer below room temperature consist of low-frequency component ascribed to the micro-Brownian motions of molecular segments in the noncrystalline regions and high-frequency component associated with the local motions of small-scale segments. By using the fitting results with one or two Cole-Cole functions, and calculating with WLF equation acid Arrhenius formula,the glass transition temperature and the activation energy of local relaxation are obtained. the distribution of relaxation time in the molten and ferroelectric phases is located at a Same line, acid complies with Arrhenius rule, which suggests that the elementary motions are of same type for molecular motions provided by the high-temperature process and the low-temperature local mode process.

关键词： FLUORIDE-TRIFLUOROETHYLENE COPOLYMERS VINYLIDENE FLUORIDE CURIE TRANSITION CO-POLYMERS BEHAVIOR TETRAFLUOROETHYLENE DEPENDENCE

Influence of Cold Deformation on the Aging Behaviour of Al-Cu-Si-Mg Alloy

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Journal of Materials Science & Technology 2011年第3期27卷 193-198页

作者： S.K.ghosh Department of Metallurgy and Materials Engineering Bengal Engineering and Science University

The present study deals with the effect of cold deformation and subsequent aging on the microstructure and mechanical properties of AI-Cu-Si-Mg alloy. Differential scanning calorimetry indicates that precipitation occurs in the temperature range of 258-272℃ for the as quenched wrought alloy. The activation energy value estimated by Kissinger method for the aforesaid precipitation reaction is obtained as 106 kJ/mol. 45% cold deformation prior to aging indicates the first dissolution reaction at about 50℃ and the precipitation reaction at a temperature of about 82℃. Microstructural investigations have revealed the formation of fine precipitates within the matrix after aging of the cold deformed sample. As-quenched alloy reveals prominently the aging response, The increase in hardness, yield and tensile strength with simultaneous decrease in elongation in the deformed alloy is found to be primarily due to the deformation strengthening and not due to the precipitation hardening.

关键词： Aluminium alloy Aging Cold deformation Differential scanning calorimetry Kissinger method

Seismic analysis of nailed vertical excavation using pseudo-dynamic approach

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Earthquake Engineering and Engineering Vibration 2016年第4期15卷 621-631页

作者： Piyush Sarangi Priyanka ghosh Department of Civil Engineering Indian Institute of Technology

An attempt has been made to study the behavior of nailed vertical excavations in medium dense to dense cohesionless soil under seismic conditions using a pseudo-dynamic approach. The effect of several parameters such as angle of internal friction of soil （φ）, horizontal （kh） and vertical （kv） earthquake acceleration coefficients, amplification factor （fa）, length of nails （L）, angle of nail inclination （a） and vertical spacing of nails （S） on the stability of nailed vertical excavations has been explored. The limit equilibrium method along with a planar failure surface is used to derive the formulation involved with the pseudo-dynamic approach, considering axial pullout of the installed nails. A comparison of the pseudo-static and pseudo-dynamic approaches has been established in order to explore the effectiveness of the pseudo-dynamic approach over pseudo-static analysis, since most of the seismic stability studies on nailed vertical excavations are based on the latter. The results are expressed in terms of the global factor of safety （FOS）. Seismic stability, i.e., the FOS of nailed vertical excavations is found to decrease with increase in the horizontal and vertical earthquake forces. The present values of FOS are compared with those available in the literature.

关键词： earthquake factor of safety pseudo-dynamic approach soil nailing vertical excavation

Estimation of tunneling effect caused by luminance non-uniformity in head-up displays

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Chinese Optics Letters 2014年第1期12卷 73-78页

作者： Vinod Karar Smarajit ghosh Department of Optical Devices and Systems CSIR-Central Scientific Instruments Organisation Department of Electrical and Instrumentation Engineering Thapar University

Head-up displays （HUDs） enable a pilot to manage aircraft activities by facilitating simultaneous access to the flight instrument data and to the outside scene. However, HUDs can also distract a pilot. This study shows that HUD luminance non-uniformity may force inappropriate distribution of attention between the events shown on HUD symbology and the outside scene because of the resultant differential contrast in the display area. Results of statistical analysis demonstrate considerable effects of HUD image luminance and ambient luminance, as well as their interaction, on the detection of events displayed on an HUD and the outside scene.

关键词： Estimation of tunneling effect caused by luminance non-uniformity in head-up displays head

Electrochemical characterization of MnO_2 as electrocatalytic energy material for fuel cell electrode

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燃料化学学报 2015年第3期43卷 344-351页

作者： Subir Paul Asmita ghosh Department of Metallurgical and Material Engineering Jadavpur University

Development of inexpensive non Pt based high electrocatalytic energy materials is the need of the hour for fuel cell electrode to produce clean alternative green energy from synthesized bio alcohol using biomass. MnO 2,electro synthesized at different current density is found to be well performed electrocatalytic material,comparable to Pt,with higher current density,very lowovervoltage for the electrochemical oxidation of methanol. From EIS study,the polarization resistance of the coated MnO 2is found to be much lowand electrical double layer capacitance is high,the effect increases with increase in current density of electro deposition. XRD,EDX and AAS analysis confirm the M nO 2deposition. The morphology of SEM images exhibits an enhanced 3D effective substrate area,for electro oxidation of the fuel. A fewnano structured grains of the deposited M nO 2is also observed at higher current density. The fact supports that a high energetic inexpensive electro catalytic material has been found for fuel cell electrode to synthesis renewable energy from methanol fuel.

关键词： electro catalytic energy material fuel cell impedance polarization electro coating

Nonlinear Dispersive and Dissipative Electrostatic Structures in Two-Dimensional Electron-Positron-Ion Quantum Plasma

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Communications in Theoretical Physics 2019年第2期71卷 237-242页

作者： Nabakumar ghosh Biswajit Sahu Department of Mathematics Mugberia Gangadhar MahavidyalayaBhupatinagarPurba Medinipur-721425India Department of Mathematics West Bengal State UniversityBarasatKolkata-700126India

The nonlinear features of two-dimensional ion acoustic(IA) solitary and shock structures in a dissipative electron-positron-ion(EPI) quantum plasma are investigated. The dissipation in the system is taken into account by incorporating the kinematic viscosity of ions in plasmas. A quantum hydrodynamic(QHD) model is used to describe the quantum plasma system. The propagation of small but finite amplitude solitons and shocks is governed by the Kadomtsev-Petviashvili-Burger(KPB) equation. It is observed that depending on the values of plasma parameters(*** diffraction, positron concentration, viscosity), both compressive and rarefactive solitons and shocks are found to exist. Furthermore, the energy of the soliton is computed and possible solutions of the KPB equation are presented numerically in terms of the monotonic and oscillatory shock profiles

关键词： quantum plasma Kadomtsev-Petviashvili-Burger equation nonlinear structures

Study of gravitational sedimentation of flexible, permeable circular and planktonic particle applying the immersed boundary method

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International Journal of Sediment Research 2023年第5期38卷 643-652页

作者： Rekha Panghal Sudeshna ghosh Department of Mathematics Amity School of Applied Sciences Amity University Haryana

The gravitational settling of a flexible, permeable circular and planktonic particle drenched in a fluid which is assumed to be Newtonian and incompressible along with being viscous was studied. A mathematical formulation and numerical simulations of the studied problem were done by applying the Immersed Boundary Method(IBM) in a two-dimensional fluid domain. Parametric studies were done for analyzing the impact of varying flexibilities and permeabilities with reference to settling velocity(terminal velocity) and shape deformation of the particle. The terminal velocity and permeability of the particle are directly proportional. It was observed that for fixed permeability, the terminal velocity increases when increasing the flexibility of the particle.

关键词： Immersed Boundary Method (IBM) Sedimentation Incompressible fluid Flexible particle Permeable particle Settling velocity