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Development of a new coated electrode with low nickel content for welding ductile iron and its response to austempering

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1090-1103页

作者： Tapan Sarkar Ajit kumar Pramanick Tapan kumar Pal Akshay kumar Pramanick Welding Technology Centre Jadavpur University Department of Forge Technology NIFFT

Coated Electrodes with small amounts of nickel were developed for welding ductile iron(DI) and conversion of the same into austempered ductile iron(ADI) after austempering. Among six electrodes, Trials 3 and 4 were selected for establishing crack-free weld deposits via preheating and post-weld heat treatment. Austenitization was performed at 900°C for 2 h and austempering at 300 or 350°C for three different holding times to observe the results of austempering with respect to the microstructure, hardness, and austempering kinetics of the samples. The microstructures of the weld deposits showed needle-like bainitic ferrite with small amounts of retained austenite when treated at 300°C and feathery bainitic ferrite with large amounts of retainedaustenite when treated at 350°C. The electrode labeled with Trial 3 revealed greater austenite contents than that labeled with Trial 4 when treated with a 2 h holding time regardless of the austempering temperature applied. The transformation rate of the bainitic ferrite of Trial 3 was relatively higher than that of Trial 4 and showed a lower rate constant, leading to a higher diffusion rate of carbon in austenite.

关键词： electrode development microstructure XRD analysis transformation kinetic microhardness

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Communications in Theoretical Physics 2014年第1期61卷 121-126页

作者： Mukesh kumar Raj kumar Department of Mathematics Motilal Nehru National Institute of Technology Allahabad

In the present work, the new exact solutions of the Boiti-Leon-Pempinelli system have been found. The system has extensive physical background. The exact solutions of the Boiti-Leon-Pempinelli system are investigated using similarity transformation method via Lie group theory. Lie symmetry generators are used for constructing similarity variables for the given system of partial differential equations, which lead to the new system of partial differentiaJ equations with one variable less at each step and eventually to a system of ordinary differential equations （ODEs）. Finally, these ODEs are solved exactly. The exact solutions are obtained under some parametric restrictions. The elastic behavior of the soliton solutions is shown graphically by taking some appropriate choices of the arbitrary functions involved in the solutions.

关键词： Boiti-Leon-Pempinelli system similarity transformation method Lie group theory soliton solutions

Charmonia and bottomonia in asymmetric magnetized hot nuclear matter

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Chinese Physics C 2019年第12期43卷 141-158页

作者： Rajesh kumar Arvind kumar Department of Physics Dr.B R Ambedkar National Institute of Technology Jalandhar

We investigate the mass-shift of P-wave charmonium(χc0,χc1),and S and P-wave bottomonium(ηb,■,χb0,andχb1)states in magnetized hot asymmetric nuclear matter using the unification of QCD sum rules(QCDSR)and the chiral S U(3)*** QCDSR,we use two approaches,i.e.,the moment sum rule and the Borel sum *** magnetic field induced scalar gluon condensateand the twist-2 gluon operatorcalculated in the chiral S U(3)model are utilised in QCD sum rules to calculate the in-medium mass-shift of the above *** attractive mass-shift of these mesons is observed,which is more sensitive to magnetic field in the high density regime for charmonium,however less so for *** results may be helpful to understand the decay of higher quarkonium states to the lower quarkonium states in asymmetric heavy ion collision experiments.

关键词： heavy mesons hot and dense matter finite magnetic field QCD sum rules chiral model

Study of intermolecular interactions in binary mixtures of methyl acrylate with benzene and methyl substituted benzenes at different temperatures:An experimental and theoretical approach

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Chinese Journal of Chemical Engineering 2022年第4期35卷 212-238页

作者： Anil kumar Nain Department of Chemistry Dyal Singh College(University of Delhi)New Delhi 110003India

The ultrasonic speeds,u and viscosities,ηof the binary mixtures of methyl acrylate with benzene,toluene,o-xylene,m-xylene,p-xylene,and mesitylene over the whole mole fraction range were measured at six different temperatures and at atmospheric *** the experimental data,the excess isentropic compressibility,κ_(s)^(E),excess ultrasonic speed,u^(E),excess molar isentropic compressibility,K_(s,m)^(E),excess specific impedance,Z^(E)and deviations in viscosity,Δηhave been *** partial molar isentropic compressions,K_(s,m,1) and K_(s,m,2),and excess partial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E) over the whole composition range,partial molar isentropic compressions,K_(s,m,1)^(-)and K_(s,m,2)^(-),and excesspartial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E)of the components at infinite dilution have also been *** results specified the existence of weak interactions between unlike molecules,and these interactions follow the order:benzene>toluene>p-xylene>m-xylene>o-xylene>mesityle *** magnitude of interactions was found to be dependent on the number and position of the methyl groups in these aromatic hydrocarbons.

关键词： Ultrasonic speed Viscosity Methyl acrylate Aromatic hydrocarbon Excess properties Intermolecular interactions

Fractionally Delayed Kalman Filter

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IEEE/CAA Journal of Automatica Sinica 2020年第1期7卷 169-177页

作者： Abhinoy kumar Singh Discipline of Electrical Engineering Indian Institute of Technology Indore

The conventional Kalman filter is based on the assumption of non-delayed measurements. Several modifications appear to address this problem, but they are constrained by two crucial assumptions: 1) the delay is an integer multiple of the sampling interval, and 2) a stochastic model representing the relationship between delayed measurements and a sequence of possible non-delayed measurements is known. Practical problems often fail to satisfy these assumptions, leading to poor estimation accuracy and frequent track-failure. This paper introduces a new variant of the Kalman filter, which is free from the stochastic model requirement and addresses the problem of fractional *** proposed algorithm fixes the maximum delay(problem specific), which can be tuned by the practitioners for varying delay possibilities. A sequence of hypothetically defined intermediate instants characterizes fractional delays while maximum likelihood based delay identification could preclude the stochastic model requirement. Fractional delay realization could help in improving estimation accuracy. Moreover, precluding the need of a stochastic model could enhance the practical applicability. A comparative analysis with ordinary Kalman filter shows the high estimation accuracy of the proposed method in the presence of delay.

关键词： Gaussian likelihood Kalman filter optimal Kalman gain randomly delayed measurements

Propagation of wave at the boundary surface of transversely isotropic thermoelastic material with voids and isotropic elastic half-space

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Applied Mathematics and Mechanics(English Edition) 2010年第9期31卷 1153-1172页

作者： Rajneesh kumar Rajeev kumar Department of Mathematics Kurukshetra UniversityKurukshetra 136119India

The purpose of this research is to study the effect of voids on the surface wave propagation in a layer of a transversely isotropic thermoelastic material with voids lying over an isotropic elastic half-space. The frequency equation is derived after developing a mathematical model for welded and smooth contact boundary conditions. The dispersion curves giving the phase velocity and attenuation coefficient via wave number are plotted graphically to depict the effects of voids and anisotropy for welded contact boundary conditions. The specific loss and amplitudes of the volume fraction field, the normal stress, and the temperature change for welded contact are obtained and shown graphically for a particular model to depict the voids and anisotropy effects. Some special cases are also deduced from the present investigation.

关键词： propagation of wave transverse isotropy thermoelastic with voids isotropic elastic half-spaze phase velocity attenuation coefficient

Analysis of frequency shifting in seismic signals using Gabor-Wigner transform

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Earthquake Engineering and Engineering Vibration 2015年第4期14卷 715-724页

作者： Roshan kumar P.Sumathi Ashok kumar Deaprtment of Earthquake Engineering IIT Roorkee Deaprtment of Electrical Engineering IIT Roorkee

A hybrid time-frequency method known as Gabor-Wigner transform (GWT) is introduced in this paper for examining the time-frequency patterns of earthquake damaged buildings. GWT is developed by combining the Gabor transform (GT) and Wigner-Ville distribution (WVD). GT and WVD have been used separately on synthetic and recorded earthquake data to identify frequency shifting due to earthquake damages, but GT is prone to windowing effect and WVD involves ambiguity function. Hence to obtain better clarity and to remove the cross terms (frequency interference), GT and WVD are judiciously combined and the resultant GWT used to identify frequency shifting. Synthetic seismic response of an instrumented building and real-time earthquake data recorded on the building were investigated using GWT. It is found that GWT offers good accuracy for even slow variations in frequency, good time-frequency resolution, and localized response. Presented results confirm the efficacy of GWT when compared with GT and WVD used separately. Simulation results were quantified by the Renyi entropy measures and GWT shown to be an adequate technique in identifying localized response for structural damage detection.

关键词： time-frequency distribution seismic signals cross-term interference Gabor transform Wigner- Ville distribution Gabor-Wigner transform

Numerical Algorithm Based on Quintic Nonpolynomial Spline for Solving Third-Order Boundary Value Problems Associated with Draining and Coating Flows

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Chinese Annals of Mathematics,Series B 2012年第6期33卷 831-840页

作者： Pankaj kumar SRIVASTAVA Manoj kumar Department of Mathematics Jaypee Institute of Information Technology Department of Mathematics Motilal Nehru National Institute of Technology

A numerical algorithm is developed for the approximation of the solution to certain boundary value problems involving the third-order ordinary differential equation associated with draining and coating flows. The authors show that the approximate so- lutions obtained by the numerical algorithm developed by using uonpolynomial quintic spline functions ave better than those produced by other spline and domain decomposition methods. The algorithm is tested on two problems associated with draining and coating flows to demonstrate the practical usefulness of the approach.

关键词： Third-order boundary value problem Spline functions Nonpolynomial quartic spline Nonpolynomial quintic spline Draining and coating flows

Major Development Under Gaussian Filtering Since Unscented Kalman Filter

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IEEE/CAA Journal of Automatica Sinica 2020年第5期7卷 1308-1325页

作者： Abhinoy kumar Singh IEEE Department of Electrical Engineering Indian Institute of Technology Indore

Filtering is a recursive estimation of hidden states of a dynamic system from noisy *** problems appear in several branches of science and technology,ranging from target tracking to biomedical monitoring.A commonly practiced approach of filtering with nonlinear systems is Gaussian *** early Gaussian filters used a derivative-based implementation,and suffered from several drawbacks,such as the smoothness requirements of system models and poor stability.A derivative-free numerical approximation-based Gaussian filter,named the unscented Kalman filter(UKF),was introduced in the nineties,which offered several advantages over the derivativebased Gaussian *** the proposition of UKF,derivativefree Gaussian filtering has been a highly active research *** paper reviews significant developments made under Gaussian filtering since the proposition of *** review is particularly focused on three categories of developments:i)advancing the numerical approximation methods;ii)modifying the conventional Gaussian approach to further improve the filtering performance;and iii)constrained filtering to address the problem of discrete-time formulation of process *** review highlights the computational aspect of recent developments in all three *** performance of various filters are analyzed by simulating them with real-life target tracking problems.

关键词： Bayesian framework cubature rule-based filtering Gaussian filters Gaussian sum and square-root filtering nonlinear filtering quadrature rule-based filtering unscented transformation