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Sadek Hossain Mallik

Other affiliations: Serampore College
Bio: Sadek Hossain Mallik is an academic researcher from University of Calcutta. The author has contributed to research in topics: Thermoelastic damping & Laplace transform. The author has an hindex of 5, co-authored 5 publications receiving 188 citations. Previous affiliations of Sadek Hossain Mallik include Serampore College.

Papers
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TL;DR: In this article, the problem of generalized thermoelastic interactions in a functionally graded isotropic unbounded medium due to the presence of periodically varying heat sources in the context of the linear theory of generalized TEWOED was considered.

65 citations

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TL;DR: In this paper, a three-phase-lag model, GN model II (TEWOED) and GN model III(TEWED) are employed to study the thermomechanical coupling, thermal and mechanical relaxation effects.
Abstract: The present paper aims at studying the thermo-visco-elastic interaction in a homogeneous, infinite Kelvin-Voigt-type viscoelastic, thermally conducting medium due to the presence of periodically varying heat sources. Three-phase-lag thermoelastic model, GN model II (TEWOED) and GN model III (TEWED) are employed to study the thermomechanical coupling, thermal and mechanical relaxation effects. In the absence of mechanical relaxations (viscous effect), the results for various generalized theories of thermoelasticity may be obtained as particular cases. The governing equations are expressed in Laplace-Fourier double transform domain and are solved in that domain. The inversion of the Fourier transform is carried out by using residual calculus, where poles of the integrand are obtained numerically in complex domain by using Laguerre’s method and the inversion of Laplace transform is done numerically using a method based on Fourier series expansion technique. The numerical estimates of the displacement, temperature and stress are obtained for a hypothetical material. A comparison of the results for different theories (three-phase-lag model, GN model II, GN model III) is presented and the effect of viscosity is also shown. In absence of viscous effect the results corresponding to GN model II and GN model III agree with the results of the existing literature.

52 citations

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TL;DR: In this article, a two dimensional problem for a transversely isotropic thick plate having heat source was solved in the context of generalized thermoelasticity proposed by Green and Naghdi, and the governing equations for displacement and temperature fields were obtained in Laplace-Fourier transform domain.
Abstract: This paper deals with a two dimensional problem for a transversely isotropic thick plate having heat source. The upper surface of the plate is stress free with prescribed surface temperature while the lower surface of the plate rests on a rigid foundation and is thermally insulated. The study is carried out in the context of generalized thermoelasticity proposed by Green and Naghdi. The governing equations for displacement and temperature fields are obtained in Laplace–Fourier transform domain by applying Laplace and Fourier transform techniques. The inversion of double transform has been done numerically. The numerical inversion of Laplace transform is done by using a method based on Fourier Series expansion technique. Numerical computations have been done for magnesium (Mg) and the results are presented graphically. The results for an isotropic material (Cu) have been deduced numerically and presented graphically to compare with those of transversely isotropic material (Mg).

47 citations

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TL;DR: In this article, an internal penny-shaped crack subjected to prescribed temperature and stress distribution in an infinite thermoelastic solid which obeys classical coupled thermo-elasticity theory (CCTE), the Lord-Shulman (L-S) and Green-Naghdi (G-N) models of thermo elasticity is considered.
Abstract: This paper is concerned with an internal penny-shaped crack subjected to prescribed temperature and stress distribution in an infinite thermoelastic solid which obeys classical coupled thermoelasticity theory (CCTE), the Lord–Shulman (L-S) and Green–Naghdi (G-N) models of thermoelasticity. The generalized coupled thermoelasticity theories are combined into a unified formulation introducing the unified parameters. The Laplace and Hankel transforms are used to solve the problem. The boundary conditions of the problem give a set of four dual integral equations. The operators of fractional calculus are used to transform the dual integral equations into a Fredholm integral equation of second kind, which is then solved numerically. The infersions of double transforms have been done numerically and for numerical inversion of Laplace transform Bellman method is used. Numerical results for temperature, displacements, stress near the crack and stress intensity factor are shown graphically for classical coupled ther...

30 citations

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TL;DR: In this article , a gate tunable superconductivity in 2-DEGs generated at the surface of a (111)-oriented KTaO 3 crystal by the simple sputtering of a thin Al layer was reported.
Abstract: Abstract After almost twenty years of intense work on the celebrated LaAlO 3 /SrTiO 3 system, the recent discovery of a superconducting two-dimensional electron gas (2-DEG) in (111)-oriented KTaO 3 -based heterostructures injects new momentum to the field of oxides interface. However, while both interfaces share common properties, experiments also suggest important differences between the two systems. Here, we report gate tunable superconductivity in 2-DEGs generated at the surface of a (111)-oriented KTaO 3 crystal by the simple sputtering of a thin Al layer. We extract the superfluid stiffness of the 2-DEGs and show that its temperature dependence is consistent with a node-less superconducting order parameter having a gap value larger than expected within a simple BCS weak-coupling limit model. The superconducting transition follows the Berezinskii-Kosterlitz-Thouless scenario, which was not reported on SrTiO 3 -based interfaces. Our finding offers innovative perspectives for fundamental science but also for device applications in a variety of fields such as spin-orbitronics and topological electronics.

13 citations


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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this article, a memory-dependent derivative (MDD) was introduced into the Lord and Shulman (LS) generalized thermoelasticity, which might be superior to fractional ones.

189 citations

Journal ArticleDOI
TL;DR: In this article, the authors considered the problem of a two-dimensional thermoelastic half-space in the context of generalized thermo-elastic theory with one relaxation time.
Abstract: In this article, we consider the problem of a two-dimensional thermoelastic half-space in the context of generalized thermoelastic theory with one relaxation time. The surface of the half-space is taken to be traction free and thermally insulated. The solution of the considered physical quantity can be broken down in terms of normal modes. The nonhomogeneous basic equations have been written in the form of a vector-matrix differential equation, which is then solved by an eigenvalue approach. The exact analytical solution is adopted for the temperature, the components of displacement and stresses. The results obtained are presented graphically for the effect of laser pulse to display the phenomena physical meaning. The graphical results indicate that the thermal relaxation time has a great effect on the temperature, the components of displacement and the components of stress.

101 citations

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TL;DR: In this article, the Laplace transformation has been applied to the problem of determining the thermo-elastic interaction due to step input of temperature on the boundaries of a functionally graded orthotropic hollow sphere in the context of linear theories of generalized thermoelasticity.
Abstract: This problem deals with the determination of thermo-elastic interaction due to step input of temperature on the boundaries of a functionally graded orthotropic hollow sphere in the context of linear theories of generalized thermo-elasticity. Using the Laplace transformation the fundamental equations have been expressed in the form of vector–matrix differential equation which is then solved by eigenvalue approach. The inverse of the transformed solution is carried out by applying a method of Bellman et al. Stresses, displacement and temperature distributions have been computed numerically and presented graphically in a number of figures. A comparison of the results for different theories (TEWOED(GN-II), TEWED(GN-III) and three-phase-lag model) is presented. When the material is homogeneous, isotropic and outer radius of the hollow sphere tends to infinity, the corresponding results agree with that of existing literature for GN-III model.

93 citations

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TL;DR: In this paper, a modified couple stress theory has been developed to capture the size effect in the small-size investigation of microbeams, where the microbeam is subjected to an inclined load of a linear combination of normal and tangential ones.
Abstract: This article presents a refined two-temperature multi-phase-lags thermoelasticity theory for the thermomechanical response of microbeams. The modified couple stress theory has been developed to capture the size effect in the small-size investigation. The microbeam is subjected to an inclined load of a linear combination of normal and tangential ones. Three partial differential equations of the modified couple stress microbeam are derived and solved exactly using the normal mode analysis. The influences of changing inclination angle, two-temperature parameter, and scale parameter on the field quantities like temperature, displacements, stresses, and couple stresses are investigated. Results of some earlier works are also deduced from the present investigation as special cases. Some comparisons are tabulated and presented graphically to estimate the effects of the scale parameter, the two-temperature parameter, the dual-phase-lags parameters, and the inclination angle. It is shown that the two-temperature parameter has a strong effect on the thermodynamic and conductive temperatures. However, the scale parameter and inclination angle have a very strong effect on all the field quantities of the microbeam.

67 citations