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Determining the relationship between chemical composition and size, shape and effective density of airborne fine particles through concurrent use of inertial and optical based measurements

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Particuology 2016年第5期14卷 93-101页

作者： Anand kumar tarun Gupta Environmental Engineering and Management Program Indian Institute of Technology Kanpur Kanpur 208016 India Institute of Atmospheric and Climate Science Swiss Federal Institute of Technology Zurich Zurich 8092 Switzerland Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur 208016 India

This study presents the development of a medium flow, multiple slit based PM2.5 （particle aerodynamic diameter 〈2.5 μm） inertial impactor. Its performance was compared with that of a light scattering based optical particle sizer in a field study and in controlled lab based experiments using polydisperse dolomite powder as test aerosol. The impactor＇s optimum nozzle configuration had a cutoff size of 2.51 μm （aero- dynamic diameter） at an operating flow rate of 215 L/rain with a pressure drop of 0.35 kPa across the impactor stage. Because the apparent particle density of an ambient aerosol depends on the physical properties and the chemical composition of the particles, the PM2.5 mass concentration was measured with an optical particle sizer and an inertial impactor over a weekday and a weekend day in a field study during which the effective particle shape factor and density were in tandem modified in order to com- pare the results from the two sampling techniques. The correlation of the two instrument results tended towards 1：1 with increasing values of shape factor （irregular shaped） and effective particle density. This observation was supported through chemical investigations of the collected mass, which showed a higher percentage contribution from elements which are mostly of crustal nature （namely, Ca, Fe, and Mg）.

关键词： lmpactor PM2.5 Optical particle counter Effective particle density Shape factor

Effect of relaxation times on circular crested waves in thermoelastic diffusive plate

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Applied Mathematics and Mechanics(English Edition) 2010年第4期31卷 493-500页

作者： Rajneesh kumar tarun KANSAL Department of Mathematics Kurukshetra University

The propagation of circularly crested thermoelastic diffusive waves in an infinite homogeneous transversely isotropic plate subjected to stress free, isothermal/insulated and chemical potential conditions is investigated in the framework of different thermo- elastic diffusion theories. The dispersion equations of thermoelastic diffusive Lamb type waves are derived. Some special cases of the dispersion equations are also deduced.

关键词： wave propagation transversely generalized thermoelastic diffusion attenuation isotropic crested waves phase velocity coefficient amplitudes

Propagation of Rayleigh waves on free surface of transversely isotropic generalized thermoelastic diffusion

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Applied Mathematics and Mechanics(English Edition) 2008年第11期29卷 1451-1462页

作者： Rajneesh kumar tarun Kansal Department of Mathematics Kurukshetra UniversityKurukshetra-136 119India

The present paper is devoted to the study of Rayleigh wave propagation in a homogeneous, transversely isotropic, thermoelastic diffusive half-space, subject to stress free, thermally insulated/isothermal, and chemical potential boundary conditions in the context of the generalized thermoelastic diffusion theory. The Green-Lindsay（GL） theory is used in the study. In this theory, thermodiffusion and thermodiffusion mechanical relaxations are governed by four different time constants. Secular equations for surface wave propagation in the considered media are derived. Anisotropy and diffusion effects on the phase velocity, attenuation coefficient are graphically presented in order to present the analytical results and make comparison. Some special cases of frequency equations are derived from the present investigation.

关键词： wave propagation transversely isotropic generalized thermoelastic diffusion phase velocity attenuation coefficient

Effects of rotation and tidal distortions on the shapes of radial velocity curves of polytropic models of pulsating variable stars

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Research in Astronomy and Astrophysics 2018年第6期18卷 17-26页

作者： tarun kumar Arvind kumar Lal Ankush Pathania School of Mathematics Thapar University

Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects.

关键词： stars: rotation stars: oscillations stars: binaries technique: radial velocities

Effect of interaction of the various modes on the radial velocity curves of the polytropic models of rotationally and tidally distorted pulsating variable stars

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Research in Astronomy and Astrophysics 2018年第12期18卷 53-66页

作者： tarun kumar Ankush Pathania Arvind kumar Lal School of Mathematics Thapar Institute of Engineering and Technology

In our previous work, we developed a model to study the effects of rotation and/or tidal distortions on anharmonic radial oscillations and hence on the radial velocity curves of the polytropic models of pulsating variable *** considered the first three modes(fundamental and the next two higher modes) for the polytropic models of index 1.5 and 3.0 in that *** the present paper, we are further extending our previous work to study the effect of the interaction of various modes on anharmonic radial oscillations and hence on radial velocity curves of the rotationally and/or tidally distorted polytropic models of pulsating variable *** this purpose, we have considered the following cases:(i) fundamental mode(ii) fundamental and the first mode,(iii) fundamental and the next two modes and finally(iv) fundamental and the next three higher modes of pulsation in our *** objective of this paper is also to investigate whether the interaction of various modes affects the results of our previous study or *** results of this study show that the interaction of the fundamental mode with higher modes appreciably changes the shape of the radial velocity curve of rotationally distorted and rotationally and tidally distorted polytropic models of pulsating variable stars.

关键词： stars:rotation stars:oscillations stars:binaries technique:radial velocities

Fuzzy Reliability and Availability of System under a Calendar-based Inspection Involving Multiple Failures and Its Application to Wind Turbine System

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Journal of Systems Science and Systems Engineering 2024年第2期33卷 187-206页

作者： Mintu kumar Himani pant S.B.Singh Department of Mathematics Statistics and Computer Science G.B.Pant University of AgricultureTechnologyPantnagarUttarakhandIndia

Uncertainty is an important factor that needs to be considered while analyzing the performance of any engineering *** order to quantify uncertainty,fuzzy set theory is frequently used by most of researchers,including energy system *** to the classical reliability theory,component lifetimes have crisp parameters,but due to uncertainty and inaccuracy in data,it is sometimes very difficult to determine the exact values of these parameters in real-world *** overcome this difficulty in the current research,failure and repair rates were taken as triangular fuzzy numbers to determine the fuzzy availability of a system undergoing calendar-based periodic inspection subject to multiple failure modes(FMs).It was assumed that each component in the system had an exponential failure rate and repair rate with fuzzy *** FMs were explicitly taken into account when a functional state of the system was *** FM had a random failure *** the occurrence of any failure,a random time was selected for the relevant corrective repair *** proposed research was studied for one of the major sources of green energy,namely a wind turbine system wherein all the derived propositions have been implemented on it.

关键词： Fuzzy reliability fuzzy availability wind turbine system multiple failure modes triangular fuzzy number

Viscosity and Diffusion Effects at the Boundary Surface of Viscous Fluid and Thermoelastic Diffusive Solid Medium

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Advances in Applied Mathematics and Mechanics 2011年第2期3卷 219-238页

作者： Rajneesh kumar tarun Kansal Department of Mathematics Kurukshetra UniversityKurukshetra-136119India

This paper concentrates on the wave motion at the interface of viscous compressible fluid half-space and homogeneous isotropic,generalized thermoelastic diffusive *** wave solutions in both the fluid and thermoelastic diffusive half-spaces have been investigated;and the complex dispersion equation of leaky Rayleigh wave motion have been *** phase velocity and attenuation coefficient of leaky Rayleigh waves have been computed from the complex dispersion equation by using the Muller’s *** amplitudes of displacements,temperature change and concentration have been *** effects of viscosity and diffusion on phase velocity and attenuation coefficient of leaky Rayleigh waves motion for different theories of thermoelastic diffusion have been depicted graphi*** magnitude of heat and mass diffusion flux vectors for different theories of thermoelastic diffusion have also been computed and represented graphically.

关键词： Viscous compressible fluid isotropic thermoelastic diffusion phase velocity attenuation coefficient.

Prediction and optimization of machining forces using oxley’s predictive theory and RSM approach during machining of WHAs

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Defence Technology（防务技术） 2019年第6期15卷 923-935页

作者： Chithajalu Kiran Sagar tarun kumar Amrita Priyadarshini Amit kumar Gupta Mechanical Engineering Department BITS-PilaniHyderabad Campus

Tungsten heavy alloys have come up as one of the best alternatives for high density fragmenting devices and armor piercing *** is mandatory for obtaining the final shapes of such kind of ***,due to high density and elastic stiffness of WHAs,cutting forces will be higher than for most of the metals and alloys;thus,making the machining operation *** machining variable,namely,cutting force components are significantly influenced by the cutting *** paper makes use of Oxley’s predictive analytical model in conjunction with Johnson-Cook constitutive equation to predict forces under different speed and feed combinations during machining of 95 W tungsten heavy *** cutting forces,so predicted by Ml,are considered as input data for the optimization of cutting parameters(cutting speed and feed)using Response Surface Method(RSM).

关键词： Tungsten heavy alloy Machinability Response surface method Oxley’s method

HERMAN RINGS WITH SMALL PERIODS AND OMITTED VALUES

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Acta Mathematica Scientia 2018年第6期38卷 1951-1965页

作者： tarun kumar CHAKRA Gorachand CHAKRABORTY Tarakanta NAYAK School of Basic Sciences Indian Institute of Technology Bhubaneswar Department of Mathematics Goverment General Degree College

All possible arrangements of cycles of three periodic as well as four periodicHerman rings of transcendental meromorphic functions having at least one omitted value aredetermined. It is shown that if p = 3 or 4, then the number of p-cycles of Herman rings isat most one. We have also proved a result about the non-existence of a 3-cycle and a 4-cycleof Herman rings simultaneously. Finally some examples of functions having no Herman ringare discussed.

关键词： omitted values Herman rings and transcendental meromorphic functions