• فهرست مقالات Laplace

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        1 - Effect of obliqueness of external magnetic field on the characteristics of magnetized plasma wakefield
        Maryam Manouchehrizadeh Davoud Dorranian
        10.1186/2251-7235-7-43
        AbstractA direct three-dimensional model to study the wakefield in underdense magnetized plasma is introduced. The model is based on an analytic procedure by Laplace transformation for calculating the magnetized plasma wake equations. Wakefield is excited using a high-i چکیده کامل
        AbstractA direct three-dimensional model to study the wakefield in underdense magnetized plasma is introduced. The model is based on an analytic procedure by Laplace transformation for calculating the magnetized plasma wake equations. Wakefield is excited using a high-intensity ultrashort laser beam. In the presence of external magnetic field perpendicular to the direction of the laser pulse propagation direction, plasma electrons rotate around the magnetic field lines, leading to the generation of an electromagnetic component of the plasma wakes at plasma frequency. This component is polarized perpendicularly to the direct current magnetic field lines and propagates in the forward direction and normal direction with respect to the laser pulse propagation direction, both perpendiculars to the direction of the applied magnetic field. Intensity of the radiation in different plasma densities and different magnetic field strengths has been observed. پرونده مقاله
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        2 - Solutions of Morse potential with position-dependent mass by Laplace transform
        S. Miraboutalebi
        10.1007/s40094-016-0232-x
        AbstractIn the framework of the position-dependent mass quantum mechanics, the three dimensional Schrödinger equation is studied by applying the Laplace transforms combining with the point canonical transforms. For the potential analogues to Morse potential and via the چکیده کامل
        AbstractIn the framework of the position-dependent mass quantum mechanics, the three dimensional Schrödinger equation is studied by applying the Laplace transforms combining with the point canonical transforms. For the potential analogues to Morse potential and via the Pekeris approximation, we introduce the general solutions appropriate for any kind of position dependent mass profile which obeys a key condition. For a specific position-dependent mass profile, the bound state solutions are obtained through an analytical form. The constant mass solutions are also relived. پرونده مقاله
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        3 - روش تکرار تغییرات یانگ- لاپلاس کسری موضعی برای حل معادلات دیفرانسیل جزئی کسری موضعی
        هما افراز جعفر صابری نجفی
        در دهه های اخیر نظریه حساب کسری موضعی به طور موفقیت آمیزی برای توصیف و حل مسائل علوم پایه و مهندسی استفاده شده است .دراین پژوهش ، روش تکرارتغییرات یانگ لاپلاس کسری موضعی برای حل معادلات دیفرانسیل با مشتقات جزئی کسری موضعی روی مجموعه کانتور استفاده شده است. جواب‌های دقی چکیده کامل
        در دهه های اخیر نظریه حساب کسری موضعی به طور موفقیت آمیزی برای توصیف و حل مسائل علوم پایه و مهندسی استفاده شده است .دراین پژوهش ، روش تکرارتغییرات یانگ لاپلاس کسری موضعی برای حل معادلات دیفرانسیل با مشتقات جزئی کسری موضعی روی مجموعه کانتور استفاده شده است. جواب‌های دقیق و تقریبی مشتق ناپذیر برای انواع معادلات دیفرانسیل خطی وغیرخطی بدست آمده است. نشان‌داده شده است که روش استفاده شده یک روش آسان و کارآمد برای اجرا در مسائل خطی وغیر خطی ناشی در علوم و مهندسی می‌باشد. دراین مقاله روی روش تکرارتغییرات یانگ لاپلاس کسری موضعی که از ترکیب روش تکرار تغییرات کسری موضعی وتبدیل یانگ لاپلاس بدست آمده است، تاکید شده است. بیشتر جواب‌های حاصل از این روش به صورت سری بدست می‌آیند که معمولا با سرعت به جواب‌های دقیق یا تقریبی همگرا می شوند. مثال های تشریحی نشان می دهدکه این روش قادر به کاهش حجم محاسبات نسبت به روش های کلاسیک موجود می باشد.. پرونده مقاله
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        4 - Fuzzy Laplace transform on two order derivative andSolving Fuzzy two order di erential equations
        مهدی ملکی
        پرونده مقاله
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        5 - Semi-analytical ‎M‎ethod to Solve the Non-linear System of Equations to Model of Evolution for Smoking Habit in ‎Spain
        S. Noeiaghdam K. Kamal Ali
        An epidemiological model of smoking habit is studied by using one of flexible and accurate semi-analytical methods. For this reason, the homotopy analysis transform method (HATM) is applied. Convergence theorem is studied and several h-curves are demonstrated to show th چکیده کامل
        An epidemiological model of smoking habit is studied by using one of flexible and accurate semi-analytical methods. For this reason, the homotopy analysis transform method (HATM) is applied. Convergence theorem is studied and several h-curves are demonstrated to show the convergence regions. Also, the optimal convergence regions are obtained by demonstrating the residual error functions versus h. The numerical tables are presented to show the precision of method. پرونده مقاله
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        6 - Study on usage of Elzaki transform for the ordinary differential equations with non-constant ‎coefficients
        M. Eslaminasab S. Abbasbandy
        Although Elzaki transform is stronger than Sumudu and Laplace transforms to solve the ordinary differential equations withnon-constant coefficients, but this method does not lead to finding the answer of some differential equations. In this paper, a method is introduced چکیده کامل
        Although Elzaki transform is stronger than Sumudu and Laplace transforms to solve the ordinary differential equations withnon-constant coefficients, but this method does not lead to finding the answer of some differential equations. In this paper, a method is introduced to find that a differential equation by Elzaki transform can be ‎solved?‎ پرونده مقاله
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        7 - ‎Solving Some Initial-Boundary Value Problems Including Non-classical ‎C‎ases of Heat Equation By Spectral and Countour Integral ‎Methods‎
        M. Jahanshahi N. Aliev F. Jahanshahi
        In this paper, we consider some initial-boundary value problems which contain one-dimensional heat equation in non-classical case. For this problem, we can not use the classical methods such as Fourier, Laplace transformation and Fourier-Birkhoff methods. Because the ei چکیده کامل
        In this paper, we consider some initial-boundary value problems which contain one-dimensional heat equation in non-classical case. For this problem, we can not use the classical methods such as Fourier, Laplace transformation and Fourier-Birkhoff methods. Because the eigenvalues of their spectral problems are not strictly and they are repeated or we have no eigenvalue. The presentation of the solution and also satisfying the solution in the given P.D.E and satisfing the given initial and boundary conditions are established by complex analysis theory and Countour integral ‎method. پرونده مقاله
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        8 - Modified homotopy perturbation method for solving non-linear oscillator's ‎equations
        A. R. Vahidi Z. Azimzadeh M. Shahrestani‎
        In this paper a new form of the homptopy perturbation method is used for solving oscillator differential equation, which yields the Maclaurin series of the exact solution. Nonlinear vibration problems and differential equation oscillations have crucial importance in all چکیده کامل
        In this paper a new form of the homptopy perturbation method is used for solving oscillator differential equation, which yields the Maclaurin series of the exact solution. Nonlinear vibration problems and differential equation oscillations have crucial importance in all areas of science and engineering. These equations equip a significant mathematical model for dynamical systems. The accuracy of the Solution equation is very important because the analysis component of the system like vibration amplitude control, synchronization dynamics are dependent to the exact solution of oscillation ‎equation. پرونده مقاله
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        9 - مدل سازی خط انتقال هوایی در حوزه لاپلاس برای شبیه سازی پدیده تخلیه بازگشتی
        محمد حسین قاسمی پیمان نادری محمد رضا علیزاده پهلوانی
        پدیده تخلیه بازگشتی در خطوط انتقال هوایی ولتاژ بالا زمانی رخ می دهد که موج صاعقه به دکل و یا سیم های محافظ اصابت نماید. در این مقاله در مرحله محاسبه برخورد موج صاعقه به خطوط انتقال هوایی، مدل ها و پارامترهای مستقل از فرکانس برای تجزیه و تحلیل در حوزه لاپلاس به خطوط انتق چکیده کامل
        پدیده تخلیه بازگشتی در خطوط انتقال هوایی ولتاژ بالا زمانی رخ می دهد که موج صاعقه به دکل و یا سیم های محافظ اصابت نماید. در این مقاله در مرحله محاسبه برخورد موج صاعقه به خطوط انتقال هوایی، مدل ها و پارامترهای مستقل از فرکانس برای تجزیه و تحلیل در حوزه لاپلاس به خطوط انتقال هوایی KV 115 اختصاص داده شده و سپس با استفاده از نرم افزار MATLAB به شبیه سازی تفاضل ولتاژ دو سر زنجیر مقره خطوط مورد نظر برای بدست آوردن میزان اضافه ولتاژ پدیده تخلیه بازگشتی خواهیم پرداخت. در پایان مقایسه ای بین نتایج بدست آمده در حوزه لاپلاس با نتایج بدست آمده در حالت وابسته به فرکانس در نرم افزار ATPDraw صورت خواهد گرفت. پرونده مقاله
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        10 - Free Vibration Analysis of Nonlinear Circular Plates Resting on Winkler and Pasternak Foundations
        M.G Sobamowo S.A Salawu
        10.22034/jsm.2019.1866236.1423
        Dynamic behaviour of nonlinear free vibration of circular plate resting on two-parameters foundation is studied. The governing ordinary differential equation is solved analytically using hybrid Laplace Adomian decomposition method. The analytical solutions obtained are چکیده کامل
        Dynamic behaviour of nonlinear free vibration of circular plate resting on two-parameters foundation is studied. The governing ordinary differential equation is solved analytically using hybrid Laplace Adomian decomposition method. The analytical solutions obtained are verified with existing results in literature. The analytical solutions are used to determine the influence of elastic foundation, radial and circumferential stress on natural frequency of the plate. Also, the radial and circumferential stress determined. From the results, it is observed that, increase in elastic foundation parameter increases the natural frequency of the plate. It is recorded that the modal radial and circumferential stress affect the extrema mode of the plate. It is hoped that the present study will contribute to the existing knowledge in the field of vibration analysis of engineering structures. پرونده مقاله
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        11 - Effects of Viscosity on a Thick Circular Plate in Thermoelastic Diffusion Medium
        R Kumar Sh Devi
        10.22034/jsm.2019.667247
        The problem treated here is to determinethe viscosity effect on stresses, temperature change and chemical potential in a circular plate. The mathematical formulation is applied to two theories of thermoelastic diffusion developed by Sherief et al. [27] with one relaxati چکیده کامل
        The problem treated here is to determinethe viscosity effect on stresses, temperature change and chemical potential in a circular plate. The mathematical formulation is applied to two theories of thermoelastic diffusion developed by Sherief et al. [27] with one relaxation time and Kumar and Kansal [9]with two relaxation times. Laplace and Hankel transform techniques are used to obtain the expression for the displacement components, stresses, temperature change and chemical potential. The resulting quantities are computed numerically and depicted graphically by using numerical inversion technique for a particular model. Effect of viscosity is shown in the normal stress, tangential stress, temperature change and chemical potential. Some particular cases of interest are also deduced. Viscoelastic materials play an important role in many branches of engineering, technology and, in recent years, biomechanics. Viscoelastic materials, such as amorphous polymers, semicrystalline polymers, and biopolymers, can be modelled in order to determine their stress or strain interactions as well as their temporal dependencies. پرونده مقاله
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        12 - An Interval Parametric Approach for the Solution of One Dimensional Generalized Thermoelastic Problem
        S Mandal S Pal Sarkar T Kumar Roy
        10.22034/jsm.2021.1906291.1630
        This paper is presenting the solutions of the one dimension generalized thermo-elastic coupled equations by considering some thermo-elastic constants as interval numbers. As most of the elastic constants are obtained using the experimental methods. Thus there might be s چکیده کامل
        This paper is presenting the solutions of the one dimension generalized thermo-elastic coupled equations by considering some thermo-elastic constants as interval numbers. As most of the elastic constants are obtained using the experimental methods. Thus there might be some deficiency of exactness to obtain such constants. This kind of deficiency might cause the results on a micro-scale. L-S model has been considered to study the effect of such an interval parametric approach to generalized thermoelasticity. Laplace transform method applied to obtain a system of coupled ordinary differential equations. Then the vector-matrix differential form is used to solve these equations by the eigenvalue approach in Laplace transformed domain. The solution in the space-time domain obtained numerically. The numerical solutions obtained by using some suitable inverse transformation method. The solutions are graphically represented for different values of the parameter of interval parametric form and the significance of obtained results are described along with the behavior of the solutions. پرونده مقاله
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        13 - Photothermoelastic Investigation of Semiconductor Material Due to Distributed Loads
        N Sharma R Kumar
        10.22034/jsm.2020.1907462.1639
        A dynamic mathematical model of photothermoelastic (semiconductor) medium is developed to analyze the deformation due to inclined loads. The governing equations for photothermoelastic with dual phase lag model are framed for two dimensional case and are further simplifi چکیده کامل
        A dynamic mathematical model of photothermoelastic (semiconductor) medium is developed to analyze the deformation due to inclined loads. The governing equations for photothermoelastic with dual phase lag model are framed for two dimensional case and are further simplified by using potential function. Appropriate transforms w.r.t time (Laplace) and w.r.t space variables (Fourier) are employed on the resulting equations which convert the system of equations into differential equation. The problem is examined by deploying suitable mechanical boundary conditions. Specific types of distributed loads as uniformly distributed force and Linearly distributed force are taken to examine the utility of the model. The analytic expressions like displacements, stresses, temperature distribution and carrier density are obtained in the new domain (transformed).To recover the quantities in the physical domain, numerical inversion technique is employed. Numerical computed results with different angle of inclination vs distance are analyzed with and without dual phase lag theories of thermoelasticity in the form of visual representations. It is seen that physical field quantities are sensitive towards photothermoelastic and phase lag parameters. پرونده مقاله
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        14 - Memory Response in Thermoelastic Plate with Three-Phase-Lag Model
        S Biswas
        10.22034/jsm.2021.1902285.1611
        In this article, using memory-dependent derivative (MDD) on three-phase-lag model of thermoelasticity, a new generalized model of thermoelasticity theory with time delay and kernel function is constructed. The governing coupled equations of the new generalized thermoela چکیده کامل
        In this article, using memory-dependent derivative (MDD) on three-phase-lag model of thermoelasticity, a new generalized model of thermoelasticity theory with time delay and kernel function is constructed. The governing coupled equations of the new generalized thermoelasticity with time delay and kernel function are applied to two dimensional problem of an isotropic plate. The two dimensional equations of generalized thermoelasticity with MDD are solved using state space approach. Numerical inversion method is employed for the inversion of Laplace and Fourier transforms. The displacements, temperature and stress components for different thermoelastic models are presented graphically and the effect of different kernel and time delay on the considered parameters are observed. پرونده مقاله
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        15 - A Problem of Axisymmetric Vibration of Nonlocal Microstretch Thermoelastic Circular Plate with Thermomechanical Sources
        R Kumar R Rani A Miglani
        10.22034/jsm.2019.664213
        In the present manuscript, we investigated a two dimensional axisymmetric problem of nonlocal microstretch thermoelastic circular plate subjected to thermomechanical sources. An eigenvalue approach is proposed to analyze the problem. Laplace and Hankel transforms are us چکیده کامل
        In the present manuscript, we investigated a two dimensional axisymmetric problem of nonlocal microstretch thermoelastic circular plate subjected to thermomechanical sources. An eigenvalue approach is proposed to analyze the problem. Laplace and Hankel transforms are used to obtain the transformed solutions for the displacements, microrotation, microstretch, temperature distribution and stresses. The results are obtained in the physical domain by applying the numerical inversion technique of transforms. The results of the physical quantities have been obtained numerically and illustrated graphically. The results show the effect of nonlocal in the cases of Lord Shulman (LS), Green Lindsay (GL) and coupled thermoelasticity (CT) on all the physical quantities. پرونده مقاله
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        16 - Thermomechanical Response in Thermoelastic Medium with Double Porosity
        R Kumar R Vohra M.G Gorla
        A dynamic two dimensional problem of thermoelasticity with double porous structure has been considered to investigate the disturbance due to normal force and thermal source. Laplace and Fourier transform technique is applied to the governing equations to solve the probl چکیده کامل
        A dynamic two dimensional problem of thermoelasticity with double porous structure has been considered to investigate the disturbance due to normal force and thermal source. Laplace and Fourier transform technique is applied to the governing equations to solve the problem. The transformed components of stress and temperature distribution are obtained .The resulting expressions are obtained in the physical domain by using numerical inversion technique. Numerically computed results for these quantities are depicted graphically to study the effect of porosity. Results of Kumar & Rani [42] and Kumar & Ailawalia [43] have also been deduced as special cases from the present investigation. پرونده مقاله
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        17 - Axi-Symmetric Deformation Due to Various Sources in Saturated Porous Media with Incompressible Fluid
        R Kumar S Kumar M.G Gourla
        The general solution of equations of saturated porous media with incompressible fluid for two dimensional axi-symmetric problem is obtained in the transformed domain. The Laplace and Hankel transforms have been used to investigate the problem. As an application of the a چکیده کامل
        The general solution of equations of saturated porous media with incompressible fluid for two dimensional axi-symmetric problem is obtained in the transformed domain. The Laplace and Hankel transforms have been used to investigate the problem. As an application of the approach concentrated source and source over circular region have been taken to show the utility of the approach. The transformed components of displacement, stress and pore pressure are obtained. Numerical inversion technique is used to obtain the resulting quantities in physical domain. Effect of porosity is shown on the resulting quantities. A particular case of interest is also deduced from the present investigation. پرونده مقاله
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        18 - Axisymmetric Problem of Thick Circular Plate with Heat Sources in Modified Couple Stress Theory
        R Kumar Sh Devi V Sharma
        The main aim is to study the two dimensional axisymmetric problem of thick circular plate in modified couple stress theory with heat and mass diffusive sources. The thermoelastic theories with mass diffusion developed by Sherief et al. [1] and kumar and Kansal [2] have چکیده کامل
        The main aim is to study the two dimensional axisymmetric problem of thick circular plate in modified couple stress theory with heat and mass diffusive sources. The thermoelastic theories with mass diffusion developed by Sherief et al. [1] and kumar and Kansal [2] have been used to investigate the problem. Laplace and Hankel transforms technique is applied to obtain the solutions of the governing equations. The displacements, stress components, temperature change and chemical potential are obtained in the transformed domain. Numerical inversion technique has been used to obtain the solutions in the physical domain. Effects of couple stress on the resulting quantities are shown graphically. Some particular cases of interest are also deduced. پرونده مقاله
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        19 - Size-Dependent Analysis of Orthotropic Mindlin Nanoplate on Orthotropic Visco-Pasternak Substrate with Consideration of Structural Damping
        A Ghorbanpour Arani M.H Jalaei S Niknejad A.A Ghorbanpour Arani
        10.22034/jsm.2019.665162
        This paper discusses static and dynamic response of nanoplate resting on an orthotropic visco-Pasternak foundation based on Eringen’s nonlocal theory. Graphene sheet modeled as nanoplate which is assumed to be orthotropic and viscoelastic. By considering the Mindl چکیده کامل
        This paper discusses static and dynamic response of nanoplate resting on an orthotropic visco-Pasternak foundation based on Eringen’s nonlocal theory. Graphene sheet modeled as nanoplate which is assumed to be orthotropic and viscoelastic. By considering the Mindlin plate theory and viscoelastic Kelvin-Voigt model, equations of motion are derived using Hamilton’s principle which are then solved analytically by means of Fourier series -Laplace transform method. The parametric study is thoroughly accomplished, concentrating on the influences of size effect, elastic foundation type, structural damping, orthotropy directions and damping coefficient of the foundation, modulus ratio, length to thickness ratio and aspect ratio. Results depict that the structural and foundation damping coefficients are effective parameters on the dynamic response, particularly for large damping coefficients, where response of nanoplate is damped rapidly. پرونده مقاله
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        20 - Transversely Isotropic Magneto-Visco Thermoelastic Medium with Vacuum and without Energy Dissipation
        R Kumar P Kaushal R Sharma
        In the present investigation the disturbances in a homogeneous transversely isotropic magneto-Visco thermoelastic rotating medium with two temperature due to thermomechanical sources has been addressed. The thermoelasticity theories developed by Green-Naghdi (Type II an چکیده کامل
        In the present investigation the disturbances in a homogeneous transversely isotropic magneto-Visco thermoelastic rotating medium with two temperature due to thermomechanical sources has been addressed. The thermoelasticity theories developed by Green-Naghdi (Type II and Type III) both with and without energy dissipation has been applied to the thermomechanical sources. The Laplace and Fourier transform techniques have been applied to solve the present problem. As an application, the bounding surface is subjected to concentrated and distributed sources (mechanical and thermal sources). The analytical expressions of displacement, stress components, temperature change and induced magnetic field are obtained in the transformed domain. Numerical inversion techniques have been applied to obtain the results in the physical domain. Numerical simulated results are depicted graphically to show the effect of viscosity on the resulting quantities. Some special cases of interest are also deduced from the present investigation. پرونده مقاله
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        21 - Effects of Hall Current and Rotation in Modified Couple Stress Generalized Thermoelastic Half Space due to Ramp-Type Heating
        R Kumar Sh Devi V Sharma
        The objective is to study the deformation in a homogeneous isotropic modified couple stress thermoelastic rotating medium in the presence of Hall current and magnetic field due to a ramp-type thermal source. The generalized theories of thermoelasticity developed by Lord چکیده کامل
        The objective is to study the deformation in a homogeneous isotropic modified couple stress thermoelastic rotating medium in the presence of Hall current and magnetic field due to a ramp-type thermal source. The generalized theories of thermoelasticity developed by Lord Shulman (L-S, 1967) and Green Lindsay (G-L, 1972) are used to investigate the problem. Laplace and Fourier transform technique is applied to obtain the solutions of the governing equations. The displacements, stress components, temperature change and mass concentration are obtained in the transformed domain. Numerical inversion technique has been used to obtain the solutions in the physical domain. Effects of Hall current and rotation are shown in a resulting quantities. Some special cases of interest are also deduced. پرونده مقاله
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        22 - Generalized Thermoelastic Problem of a Thick Circular Plate Subjected to Axisymmetric Heat Supply
        J.J Tripathi G.D Kedar K.C Deshmukh
        The present work is aimed at analyzing the thermoelastic disturbances in a circular plate of finite thickness and infinite extent subjected to constant initial temperature and axisymmetric heat supply. Integral transform technique is used. Analytic solutions for tempera چکیده کامل
        The present work is aimed at analyzing the thermoelastic disturbances in a circular plate of finite thickness and infinite extent subjected to constant initial temperature and axisymmetric heat supply. Integral transform technique is used. Analytic solutions for temperature, displacement and stresses are derived within the context of unified system of equations in generalized thermoelasticity in the Laplace transform domain using potential functions. Inversion of Laplace transforms is done by employing a numerical scheme. Temperature, displacement and stresses developed in the thick circular plate are obtained and illustrated graphically for copper (pure) material. پرونده مقاله
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        23 - Deformation Due to Inclined Loads in Thermoporoelastic Half Space
        R Kumar S Kumar M.G Gorla
        The present investigation is concerned with the deformation of thermoporoelastic half space with incompressible fluid as a result of inclined load of arbitrary orientation. The inclined load is assumed to be linear combination of normal load and tangential load. The Lap چکیده کامل
        The present investigation is concerned with the deformation of thermoporoelastic half space with incompressible fluid as a result of inclined load of arbitrary orientation. The inclined load is assumed to be linear combination of normal load and tangential load. The Laplace and Fourier transform technique are used to solve the problem. The concentrated force, uniformly distributed force and a moving force in time and frequency domain are taken to illustrate the utility of the approach. The transformed components of displacement, stress, pore pressure and temperature change are obtained and inverted by using a numerical inversion techniques. The variations of resulting quantities are depicted graphically. A particular case has also been deduced. پرونده مقاله
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        24 - Thermomechanical Interactions Due to Hall Current in Transversely Isotropic Thermoelastic with and Without Energy Dissipation with Two Temperatures and Rotation
        R Kumar N Sharma P Lata
        The present paper is concerned with the investigation of disturbances in a homogeneous transversely isotropic thermoelastic rotating medium with two temperatures, in the presence of the combined effects of Hall currents and magnetic field due to thermomechanical sources چکیده کامل
        The present paper is concerned with the investigation of disturbances in a homogeneous transversely isotropic thermoelastic rotating medium with two temperatures, in the presence of the combined effects of Hall currents and magnetic field due to thermomechanical sources. The formulation is applied to the thermoelasticity theories developed by Green-Naghdi Theories of Type-II and Type-III. Laplace and Fourier transform technique is applied to solve the problem. As an application, the bounding surface is subjected to concentrated and distributed sources (mechanical and thermal sources). The analytical expressions of displacement, stress components, temperature change and current density components are obtained in the transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerical simulated results are depicted graphically to show a comparison of effect of Hall current on the two theories GN-II and GN-III on resulting quantities. Some special cases are also deduced from the present investigation. پرونده مقاله
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        25 - A numerical approach for solving a nonlinear inverse di usion problem by Tikhonov regularization
        H. Molhem R. Pourgholi M. Borghei
        In this paper, we propose an algorithm for numerical solving an inverse non-linear di usion problem. In additional, the least-squares method is adopted to nd the solution. To regularize the resultant ill-conditioned linear system ofequations, we apply the Tikhonov regul چکیده کامل
        In this paper, we propose an algorithm for numerical solving an inverse non-linear di usion problem. In additional, the least-squares method is adopted to nd the solution. To regularize the resultant ill-conditioned linear system ofequations, we apply the Tikhonov regularization method to obtain the stablenumerical approximation to the solution. Some numerical experiments con- rm the utility of this algorithm as the results are in good agreement with theexact data. پرونده مقاله
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        26 - پرو مجازی از طریق نگاشت سه‌بعدی همراه با بخش‌بندی مدل سه‌بعدی
        حامد فتحی علیرضا احمدی فرد حسین خسروی
        پرو مجازی یک گزینه مناسب برای صنعت پوشاک آنلاین است. در این مقاله روشی برای ترسیم مدل سه‌بعدی لباس انتخابی بر روی مدل سه‌بعدی مشتری پیشنهاد می‌گردد. برای وصول به این هدف ابر نقاط مشتری و مانکن توسط دوربین کینکت ثبت می‌شود. برای سهولت تطابق، این مدل‌ها با استفاده از توصی چکیده کامل
        پرو مجازی یک گزینه مناسب برای صنعت پوشاک آنلاین است. در این مقاله روشی برای ترسیم مدل سه‌بعدی لباس انتخابی بر روی مدل سه‌بعدی مشتری پیشنهاد می‌گردد. برای وصول به این هدف ابر نقاط مشتری و مانکن توسط دوربین کینکت ثبت می‌شود. برای سهولت تطابق، این مدل‌ها با استفاده از توصیف گرهای رویه، به بخش‌های متناظر تقسیم می‌شوند. سپس بخش‌های متناظر از مانکن به مشتری به‌طور جداگانه نگاشت داده می شود. درنهایت، اطلاعات رنگ از ابر نقاط لباس به روی ابر نقاط مشتری انتقال می‌یابد. روش پیشنهادی دو مزیت اصلی نسبت به روش‌های موجود دارد. اول اینکه برای طراحی مدل‌های سه‌بعدی در نرم‌افزارهای گرافیکی نیازی به متخصص نیست. دوم اینکه هر بافت لباسی می‌تواند توسط مشتری انتخاب شود. نتایج آزمایش‌ها نشان‌دهنده توانایی روش پیشنهادی این مقاله در مقایسه با روش‌های موجود است. پرونده مقاله
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        27 - انتخاب سبد سهام بهینه با رویکرد ارزش در معرض ریسک چندافقی پارامتریک و ناپارامتریک
        محمد علی طبیبی سید محمدرضا داودی عبدالمجید عبدالباقی عطاآبادی
        ارزش در معرض ریسک یکی از معیارهای پرکاربرد سنجش ریسک است که حداکثر ضرر یک سبد سهام را برای یک سطح اطمینان مشخص و در یک افق زمانی معلوم اندازه می‌گیرد. ارزش در معرض ریسک دوره، مفهوم ارزش در معرض ریسک را برای یک سرمایه‌گذاری با مجموعه‌ای از افق‌ها‌ی سررسید توسیع می‌دهد. ب چکیده کامل
        ارزش در معرض ریسک یکی از معیارهای پرکاربرد سنجش ریسک است که حداکثر ضرر یک سبد سهام را برای یک سطح اطمینان مشخص و در یک افق زمانی معلوم اندازه می‌گیرد. ارزش در معرض ریسک دوره، مفهوم ارزش در معرض ریسک را برای یک سرمایه‌گذاری با مجموعه‌ای از افق‌ها‌ی سررسید توسیع می‌دهد. بدین صورت تاثیر ریسک نقدشوندگی کاهش می‌یابد و سرمایه‌گذار از فرصت تصمیم‌گیری فروش در یک مجموعه زمانی برخوردار است. در پژوهش حاضر دو مدل سبد سهام بر اساس ارزش در معرض ریسک دوره طراحی می‌گردد که اولی ناپارامتریک و بر اساس شبیه سازی تاریخی و دومی‌به صورت پارامتریک و بر اساس توزیع مخلوط نرمال-لاپلاس چندگانه در جهت برازش مناسب داده‌های دمی‌است. نتیجه مطالعه تجربی مدل‌ها‌ی طراحی شده بر روی یک سبد سهام با هشت شاخص از بورس اوراق بهادار تهران در بازه 1390 تا 1399 نشان می‌دهد که رویکرد پارامتریک در داده‌ها‌ی آزمون و در معیار متوسط بازده و نسبت شارپ، نسبت به سناریوسازی تاریخی عملکرد بهتری دارد. همچنین خطای نسبی بین ارزش در معرض ریسک دوره پیش‌بینی شده توسط سبد سهام و مقدار مشاهده شده آن در داده‌ها‌ی تست در رویکرد پارامتریک کمتر است. پرونده مقاله
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        28 - مدل‏های پیش‏بینی بازده سهام؛ برآورد توزیع بازده کل بازار و نوسانات آن بر پایه توزیع لاپلاس
        معصومه محمدی لداری ایمان داداشی
        10.30495/jdaa.2024.709475
        چکیدهدر اغلب مدل های پیش بینی بازده، از بازده کل بازار به عنوان یکی از فاکتورهای موثر بر بازده اوراق بهادار استفاده می شود. در اکثر این مدل ها همچون مدل قیمت گذاری دارایی های سرمایه ای و بلک شولز، فرض بر نرمال بودن توزیع داده ها است. این در حالیست که توزیع بازده کل، لز چکیده کامل
        چکیدهدر اغلب مدل های پیش بینی بازده، از بازده کل بازار به عنوان یکی از فاکتورهای موثر بر بازده اوراق بهادار استفاده می شود. در اکثر این مدل ها همچون مدل قیمت گذاری دارایی های سرمایه ای و بلک شولز، فرض بر نرمال بودن توزیع داده ها است. این در حالیست که توزیع بازده کل، لزوماً نرمال نبوده و اغلب تفاوت قابل توجهی با توزیع نرمال دارد. در صورت تایید چنین فرضیه ای، بازده موردانتظار پیش بینی شده توسط این مدل ها، کارآیی چندانی در تصمیم گیری های مالی نخواهد داشت. هدف این پژوهش، مدل سازی بازده کل بورس تهران براساس توزیع لاپلاس و بررسی تبعیت نوسانات بازده کل از توزیع موردنظر می باشد. جهت بررسی توزیع بازده روزانه کل و نوسانات هفتگی آن از داده های مربوط به یک دوره 15 ساله بین سال های1387 تا 1401و نرم افزار آماری R استفاده شده است. تحلیل داده ها نشان داد که بازده روزانه کل از توزیع لاپلاس پیروی کرده و نوسانات هفتگی بازده کل از توزیعی که براساس توزیع لاپلاس حاصل شده، تبعیت می کند. این یافته ها، بکارگیری مدل هایی با پیش فرض نرمال بودن بازده کل، جهت پیش بینی بازده سهام در بورس اوراق بهادار تهران را با چالشی اساسی مواجه می سازد و دلیلی واضح بر ناکارآمدی این مدل ها می باشد پرونده مقاله
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        29 - Analytical-Approximate Solution for Nonlinear Volterra Integro-Differential Equations
        M. Matinfar A. Riahifar
        In this work, we conduct a comparative study among the combine Laplace transform and modified Adomian decomposition method (LMADM) and two traditional methods for an analytic and approximate treatment of special type of nonlinear Volterra integro-differential equations چکیده کامل
        In this work, we conduct a comparative study among the combine Laplace transform and modified Adomian decomposition method (LMADM) and two traditional methods for an analytic and approximate treatment of special type of nonlinear Volterra integro-differential equations of the second kind. The nonlinear part of integro-differential is approximated by Adomian polynomials, and the equation is reduced to a simple equations. The proper implementation of combine Laplace transform and modified Adomian decomposition method can extremely minimize the size of work if compared to existing traditional techniques. Moreover, three particular examples are discussed to show the reliability and the performance of method. پرونده مقاله
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        30 - A generalization of weighted versions of the determinant, permanent and the generalized inverse of rectangular matrices
        M. Bayat
        10.30495/jlta.2022.695232
        In this paper, we first generalized the weighted versions of determinants, permanents and the generalized inverses of rectangular matrices. We also investigate some of their algebraic properties. As a by product of the above investigation, we then present a determinanta چکیده کامل
        In this paper, we first generalized the weighted versions of determinants, permanents and the generalized inverses of rectangular matrices. We also investigate some of their algebraic properties. As a by product of the above investigation, we then present a determinantal representation for the general and Moore-Penrose inverses which satisfy on certain conditions. Finally, we give a general algorithm for determining the inverse of some certain class of the rectangular matrices defined based on weighted determinants. پرونده مقاله
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        31 - Analytical Solution of Steady State Substrate Concentration of an Immobilized Enzyme Kinetics by Laplace Transform Homotopy Perturbation Method
        Devipriya Ganeshan
        The nonlinear dynamical system modeling the immobilized enzyme kinetics with Michaelis-Menten mechanism for an irreversible reaction without external mass transfer resistance is considered. Laplace transform homotopy perturbation method is used to obtain the approximate چکیده کامل
        The nonlinear dynamical system modeling the immobilized enzyme kinetics with Michaelis-Menten mechanism for an irreversible reaction without external mass transfer resistance is considered. Laplace transform homotopy perturbation method is used to obtain the approximate solution of the governing nonlinear differential equation, which consists in determining the series solution convergent to the exact solution or enabling to built the approximate solution of the problem. Numerical solutions are obtained and the results are discussed graphically. The method allows to determine the solution in form of the continuous function, which is significant for the analysis of the steady state dimensionless substrate concentration with dimensionless distance on the different support materials. پرونده مقاله
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        32 - Transient Solution of an M/M/1 Variant Working Vacation Queue with Balking
        Vijaya Laxmi Pikkala Rajesh Pilla
        This paper presents the transient solution of a variant working vacation queue with balking. Customers arrive according to a Poisson process and decide to join the queue with probability $b$ or balk with $\bar{b} = 1-b$. As soon as the system becomes empty, the server t چکیده کامل
        This paper presents the transient solution of a variant working vacation queue with balking. Customers arrive according to a Poisson process and decide to join the queue with probability $b$ or balk with $\bar{b} = 1-b$. As soon as the system becomes empty, the server takes working vacation. The service times during regular busy period and working vacation period, and vacation times are assumed to be exponentially distributed and are mutually independent. We have obtained the transient-state probabilities in terms of modified Bessel function of the first kind by employing probability generating function, continued fractions and Laplace transform. In addition, we have also obtained some other performance measures. پرونده مقاله
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        33 - Initial Value ‎P‎roblems for Fourth-Order Fuzzy Differential Equations by Fuzzy Laplace ‎‎T‎ransform
        Hülya Gültekin Çitil
        This paper is on the solutions of fuzzy initial value problems for fourth-order fuzzy differential equations with positive and negative fuzzy coefficients by fuzzy Laplace transform. Examples are solved. Conclusions are given.
        This paper is on the solutions of fuzzy initial value problems for fourth-order fuzzy differential equations with positive and negative fuzzy coefficients by fuzzy Laplace transform. Examples are solved. Conclusions are given. پرونده مقاله
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        34 - An Efficient Method to Solve the Mathematical Model of HIV Infection for CD8+ T-Cells
        Samad Noeiaghdam Emran Khoshrouye Ghiasi
        In this paper, the mathematical model of HIV infection forCD8+ T-cells is illustrated. The homotopy analysis method and the Laplace transformations are combined for solving this model. Also, the convergence theorem is proved to demonstrate the abilities of presented met چکیده کامل
        In this paper, the mathematical model of HIV infection forCD8+ T-cells is illustrated. The homotopy analysis method and the Laplace transformations are combined for solving this model. Also, the convergence theorem is proved to demonstrate the abilities of presented method for solving non-linear mathematical models. The numerical results for $N=5, 10$ are presented. Several $hbar$-curves are plotted to show the convergence regions of solutions. The plots of residual error functions indicate the precision of presented method. پرونده مقاله
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        35 - MODELING OF GROUNDWATER FLOW OVER SLOPING BEDS IN RESPONSE TO CONSTANT RECHARGE AND STREAM OF VARYING WATER LEVEL
        Rajeev Kumar Bansal
        This paper presents an analytical model characterizing unsteady groundwater flow in an unconfined aquifer resting on a sloping impervious bed. The aquifer is in contact with a constant water level at one end. The other end is connected to a stream whose level is increas چکیده کامل
        This paper presents an analytical model characterizing unsteady groundwater flow in an unconfined aquifer resting on a sloping impervious bed. The aquifer is in contact with a constant water level at one end. The other end is connected to a stream whose level is increasing form an initial level to a final level at a known exponentially decaying function of time. Moreover, the aquifer is replenished by a constant downward recharge. The linearized Boussinesq equation is solved analytically using Laplace transform technique to obtain the closed form expression for hydraulic head and flow rate at the stream-aquifer interface. The expressions derived in this study can also handle the cases of upward sloping, horizontal bed conditions and sudden rise in stream water. The validity of linearization method adopted in this study is examined by solving the nonlinear equation by an explicit numerical scheme. Response of an aquifer to the variations in bed slope, recharge rate and rise rate of the stream water is illustrated with a numerical example. Sensitivity of the flow rate with various parameters is analyzed. پرونده مقاله
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        36 - A NOTE ON THE UNSTEADY FLOW OF A VISCO-ELASTIC MAXWELL FLUID THROUGH A RECTILINEAR PIPE
        R. Dube
        The unsteady flow of a visco-elastic Maxwell fluid through a rectilinear pipe having its cross-section as a parallelogram under the influence of a axial pressure gradient (I) varying linearly with time , and (II) decreasing exponentially with time has been discussed in چکیده کامل
        The unsteady flow of a visco-elastic Maxwell fluid through a rectilinear pipe having its cross-section as a parallelogram under the influence of a axial pressure gradient (I) varying linearly with time , and (II) decreasing exponentially with time has been discussed in the present paper. Variables separable and Laplace transform methods have been used to solve the problem. پرونده مقاله
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        37 - A NEW MODIFIED HOMOTOPY PERTURBATION METHOD FOR SOLVING LINEAR SECOND-ORDER FREDHOLM INTEGRO-DIFFERENTIAL EQUATIONS
        M. Sotoodeh M. A Fariborzi Araghi
        In this paper, we tried to accelerate the rate of convergence in solving second-order Fredholm type Integro-differential equations using a new method which is based on Improved homotopy perturbation method (IHPM) and applying accelerating parameters. This method is very چکیده کامل
        In this paper, we tried to accelerate the rate of convergence in solving second-order Fredholm type Integro-differential equations using a new method which is based on Improved homotopy perturbation method (IHPM) and applying accelerating parameters. This method is very simple and the result is obtained very fast. پرونده مقاله
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        38 - تحلیل تنش اتصال چسبی تک لبه بر اساس مدل فوندانسیون سه پارامتری ویسکوالاستیک
        مهدی ویسی تبار آرش رضا یونس شکاری
        در این مطالعه، به بررسی توزیع تنش اتصال چسبی تک لبه با چسب شونده های ایزوتروپ و با استفاده از مدل فوندانسیون سه پارامتری ویسکوالاستیک پرداخته شده است. در این مدل تنش برشی در راستای ضخامت چسب ثابت و تنش قائم در این راستا متغیر فرض شده است. همچنین برای مدل سازی رفتار ویسک چکیده کامل
        در این مطالعه، به بررسی توزیع تنش اتصال چسبی تک لبه با چسب شونده های ایزوتروپ و با استفاده از مدل فوندانسیون سه پارامتری ویسکوالاستیک پرداخته شده است. در این مدل تنش برشی در راستای ضخامت چسب ثابت و تنش قائم در این راستا متغیر فرض شده است. همچنین برای مدل سازی رفتار ویسکوالاستیک چسب از مدل زنر استفاده گردیده و معادلات دیفرانسیلی حاکم به کمک معادلات تعادل و ساختاری در فضای لاپلاس استخراج شده است. سپس به طور هم زمان معادلات مذکور حل و به کمک روش عددی لاپلاس معکوس گیور- استفست نتایج از فضای لاپلاس به فضای زمان تبدیل شده است. در انتها نتایج حاصل از تحلیل مذکور با نتایج المان محدود در یک اتصال نامتقارن مقایسه گردیده است که نتایج انطباق بسیار مناسبی را نشان می دهند. بیشترین کاهش تنش برشی در نیم میلیمتری انتهای ناحیه هم پوشانی در سمت چسب شونده برنجی و بیشترین کاهش تنش تورق با گذشت زمان در نیم میلیمتری انتهای ناحیه هم پوشانی در سمت چسب شونده آلومینیومی رخ می دهد. میزان کاهش تنش بعد از حدود 11 روز بسیار کاهش یافته و به حالت پایدار می رسد. پرونده مقاله

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