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Meerut, India

Kathayat K.,North Orissa University | Panigrahi A.,Dn College | Pandey A.,North Eastern Regional Institute of Science and Technology | Kar S.,North Orissa University
Physica B: Condensed Matter | Year: 2012

The ferroelectric ceramics Ba 5RTi 3V 7O 30 (R=Ho, Gd, La) have been synthesized by solid-state reaction technique. Preliminary X-ray structural analysis confirmed a single-phase formation of the compound in orthorhombic structure. Surface morphology of the compounds was studied by scanning electron microscopy (SEM). Detailed studies of electrical properties (i.e., dielectric constant, loss tangent, ac conductivity) as a function of temperature (RT-773 K) and at four different frequencies (1 kHz, 10 kHz, 100 kHz and 1 MHz) show ferroelectric-paraelectric phase transition of the compounds of diffuse-type. The activation energy has been evaluated from ac conductivity following Arrhenius equation. The conductivity pattern shows that it is strongly frequency dependent and obeys Jonscher's power relation. © 2012 Elsevier B.V. All rights reserved. Source

Rana D.K.,University of Delhi | Srivastav V.,Solid State Physics Laboratory | Pal R.,Solid State Physics Laboratory | Yadav B.S.,Dn College
Infrared Physics and Technology | Year: 2012

Transfer length method (TLM) structures were fabricated to characterize the Ni/Au/AuGe-n +-GaAs contacts for quantum dot infrared photodetector (QDIP). Low specific contact resistance of the order of 10 -5 Ω cm 2 indicates formation of a good Ohmic contact. The current-voltage measurements show that current transport is linear with no significant interfacial modification due to alloying of the contact metal. Low contact resistance makes this scheme suitable for the fabrication of heterostructure QDIP devices. © 2011 Elsevier B.V. All rights reserved. Source

Kumar R.,Kurukshetra University | Devi S.,Dn College
Structural Engineering and Mechanics | Year: 2010

The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced. Source

Kumar R.,Kurukshetra University | Devi S.,Dn College
Journal of Solid Mechanics | Year: 2010

This paper concentrates on the reflection of plane waves in the mixture of generalized thermo elastic solid half-space. There exists quasi dilatational waves i.e. qP 1, qP 2, qT and two rotational waves S 1, S 1 in a two dimensional model of the solid. The boundary conditions are solved to obtain a system of five non-homogeneous equations for amplitude ratios. These amplitude ratios are found to depend on the angle of incidence of incident wave, mixture and thermal parameters and have been computed numerically and presented graphically. The appreciable effects of mixtures and thermal on the amplitude ratios are obtained. © 2010 IAU, Arak Branch. Source

Singh S.R.,Dn College | Jain S.,Banasthali University | Pareek S.,Banasthali University
International Journal of Industrial Engineering Computations | Year: 2013

In this paper, we develop a two-warehouse imperfect production model under two cases: (i) model starts with shortages (ii) model ends with shortages. Most of the researchers proposed the models for perfect items but we develop for imperfect quality items, which is very realistic. Demand is taken as time dependent and dependent on the production. Holding cost in rented warehouse (RW) is greater than own warehouse (OW). Deterioration is taken as Weibull distribution in both OW and RW. Shortages are allowed and partially backlogged. The effect of learning on production cost is also considered. Learning from one cycle to other cycle, improve the efficiency of the organization. A numerical example including the sensitivity analysis is given to validate the results of the production-inventory model. © 2013 Growing Science Ltd. All rights reserved. Source

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