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Article
Publication date: 8 August 2016

Samia M Said

The dual-phase-lag (DPL) model and Lord-Shulman theory with one relaxation time are applied to study the effect of the gravity field, the magnetic field, and the…

Abstract

Purpose

The dual-phase-lag (DPL) model and Lord-Shulman theory with one relaxation time are applied to study the effect of the gravity field, the magnetic field, and the hydrostatic initial stress on the wave propagation in a two-temperature generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. The paper aims to discuss this issue.

Design/methodology/approach

The exact expressions of the considered variables are obtained by using normal mode analysis.

Findings

Numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of the gravity field as well as the magnetic field. Comparisons are made between the results of the two different models with and without temperature dependent properties and for two different values of the hydrostatic initial stress. A comparison is also made between the results of the two different models for two different values of the time.

Originality/value

In the present work, the author shall formulate a two-temperature generalized magneto-thermoelastic problem for a medium with temperature dependent properties and with an internal heat source that is moving with a constant speed under the influence of a gravity field and a hydrostatic initial stress. Normal mode analysis is used to obtain the exact expressions for the displacement components, thermodynamic temperature, conductive temperature, and stress components. A comparison is carried out between the considered variables as calculated from the generalized thermoelasticity based on the DPL model and the L-S theory in the absence and presence of a magnetic field as well as a gravity field. Comparisons are also made between the results of the two theories with and without temperature dependent properties and for two different values of hydrostatic initial stress. A comparison is also made between the results of the two different models for two different values of the time.

Details

Multidiscipline Modeling in Materials and Structures, vol. 12 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 21 December 2017

Sunita Deswal, Baljit Singh Punia and Kapil Kumar Kalkal

The dual-phase-lag (DPL) model is applied to study the effect of the gravity field and micropolarity on the wave propagation in a two-temperature generalized thermoelastic…

Abstract

Purpose

The dual-phase-lag (DPL) model is applied to study the effect of the gravity field and micropolarity on the wave propagation in a two-temperature generalized thermoelastic problem for a medium. The paper aims to discuss this issue.

Design/methodology/approach

The exact expressions of the considered variables are obtained by using normal mode analysis.

Findings

Numerical results for the field quantities are given in the physical domain and illustrated graphically to show the effect of angle of inclination. Comparisons of the physical quantities are also shown in figure to study the effect of gravity and two-temperature parameter.

Originality/value

This paper is concerned with the analysis of transient wave phenomena in a micropolar thermoelastic half-space subjected to inclined load. The governing equations are formulated in the context of two-temperature generalized thermoelasticity theory with DPLs. A medium is assumed to be initially quiescent and under the effect of gravity. An analytical solution of the problem is obtained by employing normal mode analysis. Numerical estimates of displacement, stresses and temperatures are computed for magnesium crystal-like material and are illustrated graphically. Comparisons of the physical quantities are shown in figures to study the effects of gravity, two-temperature parameter and angle of inclination. Some particular cases of interest have also been inferred from the present problem.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 18 July 2019

Mohamed I.A. Othman and Ahmed E. Abouelregal

The purpose of this paper is to investigate the dynamic response for a thermoelastic infinite medium with a spherical cavity in the context of the theory of two-temperature

Abstract

Purpose

The purpose of this paper is to investigate the dynamic response for a thermoelastic infinite medium with a spherical cavity in the context of the theory of two-temperature thermoelasticity without energy dissipation.

Design/methodology/approach

The cavity is fixed and subjected to a subjected to harmonically varying temperature.

Findings

The exact expressions for displacement, temperature and thermal stresses are computed and represented graphically. These distributions are calculated for a copper material and results are analyzed.

Originality/value

Effects of non-simple heat conduction, frequency of thermal vibrations and magnetic field are depicted graphically on the field variables.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 5
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 9 November 2015

Mohamed I. Othman, W. M. Hasona and Nehal T. Mansour

The purpose of this paper is to introduce the Lord-Shulman (L-S), Green-Naghdi of type III (G-N III) and three phase lag (3PHL) theories to study the effect of a magnetic…

Abstract

Purpose

The purpose of this paper is to introduce the Lord-Shulman (L-S), Green-Naghdi of type III (G-N III) and three phase lag (3PHL) theories to study the effect of a magnetic field on generalized thermoelastic medium with two temperature.

Design/methodology/approach

The problem has been solved numerically by using the normal mode analysis.

Findings

The problem is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically thermal force is applied. Comparisons are made with the results predicted by 3PHL, G-N III and L-S in the presence and absence of magnetic field as well as two temperature.

Originality/value

Generalized thermoelastic medium.

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 12 June 2017

Mohamed I.A. Othman, Yassmin D. Elmaklizi and Nehal T. Mansoure

The purpose of this paper is to investigate the propagation of plane waves in an isotropic elastic medium under the effect of rotation, magnetic field and temperature

Abstract

Purpose

The purpose of this paper is to investigate the propagation of plane waves in an isotropic elastic medium under the effect of rotation, magnetic field and temperature-dependent properties with two‐temperatures.

Design/methodology/approach

The problem has been solved analytically by using the normal mode analysis.

Findings

The numerical results are given and presented graphically when mechanical and thermal force are applied. Comparisons are made with the results predicted by the three-phase-lag (3PHL) model and dual-phase-lag model in the presence and absence of cases where the modulus of elasticity is independent of temperature.

Originality/value

In this work, the authors study the influence of rotation and magnetic field with two‐temperature on thermoelastic isotropic medium when the modulus of elasticity is taken as a linear function of reference temperature in the context of the 3PHL model. The numerical results for the field quantities are obtained and represented graphically.

Details

Multidiscipline Modeling in Materials and Structures, vol. 13 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 April 1993

Guy Jumarie

The complexity of a general system is identified with its temperature and, analogously with Boltzmann's probability density in thermodynamics, this temperature is related…

Abstract

The complexity of a general system is identified with its temperature and, analogously with Boltzmann's probability density in thermodynamics, this temperature is related to the informational entropy of the system. The concept of informational entropy of deterministic functions provides a straightforward modelling of Brillouin's negentropy (negative entropy), therefore a system can be characterized by its complexity and its dual complexity. States composition laws for complexities expressed in terms of Shannonian entropy with or without probability, and then the approach is extended to quantum entropy of non‐probabilistic data. Outlines some suggestions for future investigation.

Details

Kybernetes, vol. 22 no. 4
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 27 August 2020

Devender Sheoran, Ramesh Kumar, Sunil Kumar and Kapil Kumar Kalkal

The purpose of this paper is to study the reflection of plane waves in an initially stressed rotating thermoelastic diffusive medium with micro-concentrations and two-temperature.

Abstract

Purpose

The purpose of this paper is to study the reflection of plane waves in an initially stressed rotating thermoelastic diffusive medium with micro-concentrations and two-temperature.

Design/methodology/approach

A two-dimensional model of generalized thermoelasticity is considered. The governing equations are transformed into the non-dimensional forms using the dimensionless variables. Then, potential functions are introduced for the decoupling of the waves. Further, appropriate boundary conditions are assumed to completely solve the problem. Finally, numerical computations are performed using MATLAB.

Findings

The problem is solved analytically and it is found that there exist five coupled waves in addition to an independent micro-concentration wave in the considered medium. The amplitude ratios and energy ratios of these reflected waves have also been computed numerically for a specific material.

Originality/value

The modulus values of amplitude ratios are presented graphically to exhibit the effects of angular velocity, initial stress, two-temperature, diffusion and micro-concentration parameters. The expressions of energy ratios obtained in explicit form are also depicted graphically as functions of angle of incidence. The law of conservation of energy at the free surface during reflection phenomenon is also verified.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 January 2018

Ayssar Nahle, Fadoua El-Hajjaji, Abdeslam Ghazoui, Nour-Eddine Benchat, Mustapha Taleb, Rafik Saddik, Abdelmalik Elaatiaoui, Mohammed Koudad and Belkheir Hammouti

The purpose of this paper is to study the inhibition effect of (6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) on the corrosion of mild steel in acidic medium by…

Abstract

Purpose

The purpose of this paper is to study the inhibition effect of (6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) on the corrosion of mild steel in acidic medium by gravimetric measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS).

Design/methodology/approach

Weight loss measurements, potentiodynamic tests and EIS were performed during this study.

Findings

(6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) was found to be a very efficient inhibitor for mild steel in 1.0 M HCl solution, reaching about 85 per cent with inhibitor concentration 1.0 × 10-3 M at 303 K.

Practical implications

(6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) was found to play an important role in the corrosion inhibition of mild steel in acidic solution.

Originality/value

This paper is intended to be added to the family of pyridazine derivatives which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 17 September 2018

Khalid Rashid and Anees Khadom

The purpose of this study is to investigate the corrosion inhibition of mild steel alloy in 2 M H3PO4 solution by the pomegranate peel extract as a friendly inhibitor was…

Abstract

Purpose

The purpose of this study is to investigate the corrosion inhibition of mild steel alloy in 2 M H3PO4 solution by the pomegranate peel extract as a friendly inhibitor was studied at various temperatures, inhibitor concentrations and immersion times.

Design/methodology/approach

A weight loss method was used to evaluate the corrosion rate. The experimental Taguchi design method was used for the distribution of experiments. The experimental design gave results which were impossible to show graphically. However, this problem was solved effectively with the aid of regression analysis.

Findings

Corrosion rate increased with temperature according to Arrhenius equation. It was found that the efficiency of inhibition was increased with an increase in the concentration of inhibitor and immersion time. However, this diminishes with increased temperature. According to Langmuir isotherm, the inhibitor was adsorbed physically on steel surface. The negative sign of estimated heat of adsorption suggests a stable spontaneous inhibition process. Combination of mathematical and statistical analysis was proposed to demonstrate the results of corrosion rate with high correlation coefficients. In addition, Fourier transform infrared spectrometer examinations confirmed that the organic inhibitor consists of phenolic components as main materials.

Originality/value

Using unconventional approach for evaluation of environmentally friendly inhibitor for corrosion of mild steel in phosphoric acid solution.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 October 2018

Kaiwen Pang, Yaojun Li, Wei Yang and Zhuqing Liu

This study aims to develop and validate a new cavitation model that considers thermodynamic effects for high-temperature water flows.

Abstract

Purpose

This study aims to develop and validate a new cavitation model that considers thermodynamic effects for high-temperature water flows.

Design/methodology/approach

The Rayleigh–Plesset equation and “B-factor” method proposed by Franc are used to construct a new cavitation model called “thermodynamic Zwarte–Gerbere–Belamri” (TZGB) by introducing the thermodynamic effects into the original ZGB model. Furthermore, the viscous term of the Rayleigh–Plesset equation is considered in the TZGB model, and the model coefficients are formulated as a function of temperature. Cavitating flows around the NACA0015 hydrofoil under different water temperatures (25°C, 50°C and 70°C) at the angle of attack of 5° are calculated.

Findings

Results of the investigated temperatures show good agreement with the available experimental data. Given that the thermodynamic and viscosity effects are included in the TZGB model and the model coefficients are treated as a function of temperature, the TZGB model shows better performance in predicting the pressure coefficient distribution and length of cavity than the original ZGB cavitation model and other models do. The TZGB model aims to determine the thermodynamic and viscosity effects and perform better than the other models in predicting the mass transfer rate, particularly in high-temperature water.

Originality/value

The TZGB model shows potential in predicting the cavitating flows at high temperature and the computational cost of this model is similar to that of the original ZGB model.

Details

Engineering Computations, vol. 35 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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