Browsing by Author "Jitendra Singh"

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A case report of valproate-induced acute pancreatitis
(Regional Institute of Medical Sciences, 2017) Virendra Atam; Jitendra Singh; Kanhaiya Agrawal; Anju Dinkar; Isha Atam
Valproic acid is a branched chain aliphatic carboxylic acid which is widely used as antiepileptic drug. Valproic acid-induced acute pancreatitis is an uncommon cause of acute pancreatitis. Hereby we describe a 23-year-old unmarried female, who developed acute pancreatitis following the 12th day of valproate monotherapy prescribed for seizure disorder. Valproate was immediately stopped and replaced with levetiracetam. She improved on conservative management. © 2017 Journal of Medical Society.
A computational solution of a phase-change material in the presence of convection under the most generalized boundary condition
(Elsevier Ltd, 2020) Vikas Chaurasiya; Dinesh Kumar; K.N. Rai; Jitendra Singh
This article presents a mathematical model describing inward melting process of a phase change material in the presence of convection under the most generalized boundary condition. It is assumed that the material within a container have different geometrical configuration like circular cylinder or sphere. All thermophysical properties of the solid and liquid regions are assumed to be homogeneous. Initially, we convert the mathematical model into an initial value problem in the form of vector matrix representation using a finite difference technique. Two numerical methods; the operational matrix of integration for Bessel functions and finite element Legendre wavelet Galerkin method, are applied to solve the initial value problem. Thus, the obtained results from both methods analyzed for constant (or time depending) temperature or constant (or time depending) heat flux. The whole study is presented in dimensionless form. The effect of Stefan number, Peclet number, Kirpichev number and Biot number on dimensionless temperature profile and dimensionless moving front are illustrated graphically. © 2020 Elsevier Ltd
A computational study of binary eutectic system with convection under volumetric freezing: A Moving Boundary Problem
(Elsevier Ltd, 2024) Susheel Kumar; Vikas Chaurasiya; Jitendra Singh
A reduction in the operating time during the solidification of an eutectic alloy is one of the prime demands in front of the investigators. The classical theory of solidification was not able to offer rapid solidification of an alloy due to not account the structural property of the material. To account convection and external heat sink effect, an external volumetric heat sink is considered and it depends on the distance and time. The thermal conductivity, density, and specific heat of the mushy zone are assumed to be the linear combination of solid and liquid regions properties with a solid fraction distribution. The mathematical model accounts for the solid fraction distribution, which has a linear relationship with the temperature of the mushy zone. The analytical solution of the problem has been determined via similarity transformation. To explore the current study, numerical data of the Copper-Aluminum alloy with 5% Copper is presented. It has been found that with a volumetric heat sink, the rate of solidification becomes faster than usual. Further, the rate of heat removal from the surface accelerates. Convection enhances the rate of freezing of the eutectic alloy. The temperature of the mushy region is going up for the increasing value of the solid fraction in mushy zone, which is lying in [0,1] and when we increase the strength of volumetric heat, then the temperature profile decreases and, the first-interface and second-interface increase gradually in the whole medium. We compared the current result with Tien and Geiger's result, and it is found in good compliance. It is expected that the current study will improve the fundamental understanding of the solidification of an eutectic alloy and reduce the time for freezing, which is useful to design industrial freezing devices for alloys. © 2024 Elsevier Ltd
A new look in heat balance integral method to a two-dimensional Stefan problem with convection
(Taylor and Francis Ltd., 2022) Vikas Chaurasiya; Subrahamanyam Upadhyay; Kabindra Nath Rai; Jitendra Singh
In the current work, we developed a new approximation function for temperature profile with the help of Legendre wavelet in heat-balance integral method (HBIM) to solve a two-dimensional moving boundary problem with moving phase change material (PCM). It is assumed that PCM moves with induced velocity u along x and y direction. In heat transfer mechanism conduction and convection driven by fluid flow in liquid region is considered. To validate the current approximate method, we compared our numerical results with a previous work and found in strong acceptance. In particular, to show the accuracy of the present approximate method, we compared our numerical results against exact solution by converting present problem into a one-dimensional standard melting problem and found in good acceptance. The effect of Péclet number on temperature profile and moving melting front are analyzed in detail. Furthermore, it is shown that with a moving phase change material (PCM) the liquid/solid interface get accelerated and hence, the melting process becomes fast. This study may be applicable in thermal management and energy storage system. © 2022 Taylor & Francis Group, LLC.
A numerical study of a moving boundary problem with variable thermal conductivity and temperature-dependent moving PCM under periodic boundary condition
(Springer Science and Business Media Deutschland GmbH, 2022) Vikas Chaurasiya; Rajneesh Kumar Chaudhary; Mohamed M. Awad; Jitendra Singh
The work in this paper concerns the study of a one-phase moving boundary problem with size-dependent thermal conductivity and moving phase change material. We have considered a time-dependent boundary condition at the surface y= 0 and a temperature-dependent moving phase change material which later both assumed in periodic nature. A quadratic profile for temperature distribution is assumed to solve the problem numerically via heat balance integral method. In a particular case, we compared our results with exact solution and found to be closed. The effect of various parameters either on temperature profile or on tracking of melting front are also discussed in detail. The parameters physically interpret that transition process becomes fast for a higher value of Stefan number or/and Peclet number while there is a small delay in the propagation of melting interface for larger value of either amplitude of moving phase change material or amplitude of periodic boundary condition. Furthermore, we discuss a comparative study on temperature profile as well as on moving melting front in case of standard problem, moving boundary problem with constant thermal conductivity and presence of convection, and moving boundary problem with variable thermal conductivity and presence of convection and obtained result shows that the transition process is faster in case of moving boundary problem with constant thermal conductivity and presence of convection and is slower in case of moving boundary problem with variable thermal conductivity and presence of convection while it is between them in case of standard problem. © 2022, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.
A numerical study on non-Fourier heat conduction model of phase change problem with variable internal heat generation
(Springer Science and Business Media B.V., 2021) Jitendra; K.N. Rai; Jitendra Singh
In this study, the authors proposed one-dimensional non-Fourier heat conduction model applied to phase change problem in the presence of variable internal heat generation and this has been performed by finite element Legendre wavelet Galerkin method (FELWGM). We derived the stability analysis of the non-Fourier heat conduction model in our present case. The finite difference technique has been used to change the non-Fourier heat conduction model into an initial value problem of vector-matrix form and then we applied Legendre wavelet Galerkin method for the numerical solution of the present problem. The location of moving interface is analytically obtained under the steady-state condition. The effectiveness of the proposed numerical technique is verified through the experimental value of parameters which indicate promising results. In addition, the effect of Stefan numbers, internal heat generation, and its linear coefficient on the location of moving interface are discussed in detail and represented graphically. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.
A numerical study on the thermal response in multi-layer of skin tissue subjected to heating and cooling procedures
(Springer Science and Business Media Deutschland GmbH, 2022) Rajneesh Kumar Chaudhary; Vikas Chaurasiya; Mohamed M. Awad; Jitendra Singh
This article deals with studies for the behavior of the temperature distribution in multi-layer skin during thermal injuries and its first aid treatment under generalized boundary condition. The finite difference scheme is used to estimate the temperature profile over time and distance. The skin is damaged by heating via generalized boundary condition, after that first aid treatment is applied by cooling phenomenon via the different cold temperature of liquids, the stability of numerical scheme has been discussed, and are also validated the numerical code accuracy by comparison the obtained results with the previous reference results. In the first aid treatment by cooling, the temperature at DS interface is increased constantly over time for a few seconds, then after that, the temperature goes down. The temperature rises along with distance as long as the heat effect is present in the skin, when the heat effect has vanished, the temperature in the skin starts to decrease. During cooling, the heat effect is decreasing faster for the second kind boundary condition in comparison to the first and third kind boundary conditions. It is observed that with a higher blood perfusion rate, skin transfers more heat into the blood due to a convection process, and for this reason, a large amount of heat can be carried away from the skin. The skin burns with 100 oC for 15 s and then we applied first aid treatment by cooling with 0 oC water. Then, it was observed from the mathematical results that 41 s of time is sufficient for cooling to save the rest of the living part of the subcutaneous tissue. The effect of blood perfusion rate, heating and cooling procedures, and generalized boundary conditions are discussed in detail and the results are presented graphically for the analysis of the behavior of the temperature response in multi-layer skin. © 2022, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.
A one-phase Stefan problem with size-dependent thermal conductivity and moving phase change material under the most generalized boundary condition
(Taylor and Francis Ltd., 2022) Vikas Chaurasiya; Rajneesh Kumar Chaudhary; Abderrahim Wakif; Jitendra Singh
In the current paper, we analyzed a one-phase moving boundary problem that includes a size-dependent thermal conductivity and a moving phase change material under the most generalized boundary condition. A numerical solution to the problem is obtained via heat balance integral method (HBIM) with an approximation of the quadratic temperature profile. In particular, numerical results are compared against the exact solution and previous work and found to be closed. The effect of dimensionless problem parameters on temperature profile and moving melting interface are shown in figures. The physical behavior of these parameters shows that the melting interface enhanced growing for a large value of either Stefan number, Péclet number or Kirpichev number while it deterred with increasing the Nusselt number. A comparative study between moving boundary problem with size-dependent thermal conductivity and moving PCM, moving boundary problem with constant thermal conductivity and moving PCM, and standard problem is presented in each kind of boundary conditions. We also found that the second kind flux boundary condition is physically more realistic for the melting process than the first and third kind temperature boundary condition for a moving boundary problem with size-no independent thermal conductivity and moving PCM. For limiting value of the Nusselt number ((Formula presented.)), we found a unique λ with the Stefan number and Péclet number. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
A strict vegetarian diet may be harmful: bilateral macular bleeding in vitamin B12 deficiency
(Oxford University Press, 2023) Jitendra Singh; Anju Dinkar
A 35-year-old Indian male office worker presented with complaints of progressive weakness, fatigability, and diminished vision. The patient followed a strict vegetarian diet. Clinical examination revealed pallor. Fundoscopy revealed a bilateral macularbleed. Vitamin B12 deficiency was determined to be the cause based on the clinical and laboratory results. Three months later, he reported a near-normal vision in both eyes and a normal complete hemogram. The present clinical picture demonstrates an unusual facet of clinical feature in vitamin B12 deficiency, an event rarely encountered. © 2023 The Author(s). Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
A study for multi-layer skin burn injuries based on DPL bioheat model
(Springer Science and Business Media B.V., 2021) Rajneesh Kumar Chaudhary; Kabindra Nath Rai; Jitendra Singh
In this paper, multi-layer skin burn injuries are studied using the DPL bioheat model when skin surface is subjected to different non-Fourier boundary conditions. A skin made of three layers known as epidermis, dermis, and subcutaneous layer. These layers assumed to be homogeneous and each layer studied separately. The metabolic heat varies linearly with temperature. The diffusion and evaporation of water in the multi-layer of skin increases heat loss in the skin layer. To solve the BVP of hyperbolic PDE, the FELWG method has been used. The whole analysis presented in a non-dimensional form and the results are shown graphically. In a particular case, the result obtained is compared with the exact solution and is in good agreement. The effects of relaxation time, layer thickness, different temperature, and non-Fourier boundary condition are analyzed at the temperature of the tissue related to the burning of the skin, and the three layers are discussed in detail. © 2020, Akadémiai Kiadó, Budapest, Hungary.
A study of solidification on binary eutectic system with moving phase change material
(Elsevier Ltd, 2021) Vikas Chaurasiya; K.N. Rai; Jitendra Singh
A one-dimensional moving boundary problem describing solidification of a eutectic system under imposed material movement occupying a semi-infinite medium is solved for two different cases of solid fraction distribution within the mushy zone. In the first case it is assumed that the solid fraction distribution has a linear relationship with temperature and in the second case solid fraction distribution is varying linearly with distance within the mushy zone. An exact solution of the problem is obtained with the help of a similarity technique. To demonstrate the current study experimental data of Al-Cu solidification are presented. All the thermal-physical properties of each part are discussed in detail for both models. The temperature profile in each region and moving interfaces are calculated for different Peclet number Pe. In the present study it is shown that the moving interfaces are enhanced, growing relatively faster and assisting in the process of phase-transition when material moves in the direction of freeze but transition is delayed when material moves in the reverse direction. It is also shown that mushy zone becomes thinner when surface temperature is lower than the solidus temperature for different Peclet numbers. In addition, the heat removal Q at the surface ξ=0 is shown with respect to time for different Peclet numbers. To validate our study, we compare our results with a previous published work and they are found to be close. © 2021 Elsevier Ltd
A study of thermal injuries when skin surface subjected under most generalized boundary condition
(Begell House Inc., 2020) Rajneesh Kumar Chaudhary; Kabindra Nath Rai; Jitendra Singh
In this paper, we studied a mathematical model describing the process of heat transfer in multi-layer of skin when the skin surface is subjected to the most generalized boundary conditions (B.C.): a multi-layer skin made of three different layers known as the epidermis, dermis, and subcutaneous layer, and each layer was studied separately. We considered time lagging heat transfer model with different physical parameters. Metabolic heat varies linearly with temperature. The mathematical model has been solved using the Finite Element Legendre Wavelet Galerkin Method (FELWGM). In the epidermis layer, we analyzed the effect of diffusion and vaporization of water which increases heat loss in a skin layer. The obtained results are shown graphically and found close to the exact solution in a special case. The effect of lagging time, perfusion of blood, vaporization, and diffusion of water on temperature related to the burning of skin layer are analyzed and discussed in detail for the three layers. © 2020 by Begell House, Inc. www.begellhouse.com.
A study on cylindrical moving boundary problem with variable thermal conductivity and convection under the most realistic boundary conditions
(Elsevier Ltd, 2022) Vikas Chaurasiya; Abderrahim Wakif; Nehad Ali Shah; Jitendra Singh
The melting of a phase change material is the most applicable process in thermal energy storage system to capture heat transfer phenomena arising in a class of moving boundary problem. Demand of present technology motivates researchers to develop new theories and techniques for thermal management of a material. Experimental work on melting of a material may be difficult and development of robust theoretical formulation in cylindrical geometry with convection is critical. While there is already available study on cylindrical moving boundary problem, but still insufficient modeling of a size-dependent thermal conductivity and convection effect is not addressed properly, which is being considered in this paper and is expected to improve the previous understanding. In this work, a one-dimensional moving boundary problem with size-dependent heat conductivity and convection effect is analyzed in cylindrical geometry. In the mathematical model, we have considered a time-dependent temperature boundary condition which later assumed in periodic form, and a convective boundary condition at the outer surface of the body. The numerical result of the problem is obtained successfully via heat-balance integral method. Our numerical result is compared with a previous work and found in good acceptance. From mathematical framework, it is found that convection delayed melting process. With a size-no independent thermal conductivity, the rate of moving front decreases more in comparison to the fixed thermal conductivity. © 2022 Elsevier Ltd
Adenovirus Meningoencephalitis and Neurocysticercosis Co-infection: First Case from India
(Bentham Science Publishers, 2023) Anju Dinkar; Jitendra Singh; J. Bhavya; Swati Singh; Nilesh Kumar; Kailash Kumar
Background: Adenovirus generally causes upper and lower respiratory tract infections. It is common in children and occasionally in adults. Neurological involvement is rare, which may be mild aseptic meningitis to potentially fatal acute necrotizing encephalopathy. Recently, viruses have been reported increasingly to cause CNS infections. Viral aetiology typically varies with age. Case Presentation: Here, we report an unusual adenovirus meningoencephalitis with a co-infection of neurocysticercosis in an immunocompetent adult patient. An 18-year-old healthy female student was admitted with fever and headache for 11 days and progressive altered behaviour for 5 days, followed by altered sensorium for 3 days. This variable and unusual presentation of adenoviral infection involv-ing CNS provoked diagnostic difficulties, but with the help of advanced diagnostics, especially molec-ular, exact aetiology was detected. Even with the neurocysticercosis infection in this patient, the outcome was not adversely affected. Conclusion: This unusual co-infection with a successful outcome is the first case of this type in litera-ture. © 2023 Bentham Science Publishers.
Amphotericin B Deoxycholate Treatment of Post–Kala-Azar Dermal Leishmaniasis in India
(American Society of Tropical Medicine and Hygiene, 2024) Shyam Sundar; Jaya Chakravarty; Jitendra Singh; Deepak Verma; Neha Agrawal; Anju Dinkar
Post–kala-azar dermal leishmaniasis (PKDL) is widely prevalent in the endemic regions of India, but its treatment remains unsatisfactory. The WHO recommends a 12-week treatment with oral miltefosine, but its ocular toxicities are a serious concern. The late 1980s and early 1990s saw the use of sodium stibogluconate and amphotericin B (AmB) for a brief period. Both drugs had frequent adverse events and were expensive, and the duration of treatments was unacceptably long. This retrospective study evaluated, analyzed, and reported the outcomes of PKDL patients treated with a shorter course of AmB, the most effective antileishmanial drug. The hospital records of PKDL patients treated with AmB by 30 alternate-day infusions over 60 days (instead of conventional 60–80 infusions over 100–120 days) between September 2010 and August 2016 were reviewed. Only patients with confirmed parasitological diagnosis were included. Their records were studied for treatment-related adverse events, end-of-treatment parasitological status, and 12-month follow-up results. One hundred two patients were eligible for this study between September 2010 and August 2016. After therapy, 92/102 (90.2%) patients improved; 3 (2.9%) had to cease treatment owing to severe adverse effects, and one died of severe diarrhea unrelated to AmB. Six (5.9%) patients withdrew consent before the treatment was complete. At the 12-month evaluation, 89/102 (87.3%) patients attained a final cure. A 30-infusion regimen of AmB remains highly effective in PKDL. Without a shorter, safer, and more economical regimen for the treatment of PKDL, it should be used until a better regimen is available. Copyright © 2024 American Society of Tropical Medicine and Hygiene.
An analytical study of coupled convective heat and mass transfer with volumetric heating describing sublimation of a porous body under most sensitive temperature inputs: Application of freeze-drying
(Elsevier Ltd, 2023) Vikas Chaurasiya; Jitendra Singh
Sublimation heat-mass transfer has great applications in the pharmaceutical and food industries, such as the preservation of biological products, accelerated freeze-drying (AFD), energy storage systems, microwave freeze-drying, and enabling long-time active covid like vaccines. The current technological demand encourages investigators to provide new knowledge for freeze-drying so that it reduces the high economic cost, prevents materials from being denatured, and remains stable for a long time. In connection with this, it is of key interest to analyze the impact of convective heat and mass transfer, the rate of water vaporization, and the volumetric heating source under the most realistic temperature inputs. Despite the available works on sublimation, there is still a lack of mathematical modeling that accounts for these informations together and is presently being considered. This paper presents a heat and mass transfer problem describing sublimation in a half-porous space. The mathematical model accounts for convective heat/mass transfer and a volumetric heat source within dried and frozen regions. In addition, convection driven by the mass transfer of ice crystals within the dried region is also considered. Three different types of temperature input are placed at the surface x=0 to obtain the rapid sublimation process without harming the material properties. The exact solution to the problem is obtained successfully by using similarity transformation. The impact of various problem parameters on sublimation is comprehensively studied. In this study, it is found that with a volumetric heating source term G0, material sublimates faster than without one. Furthermore, convective heat transfer in terms of Pe1 and Pe2, enhances the temperature within the porous medium, and as a result, material sublimates faster than usual. As the value of the convective term β goes up, a reduction in the temperature field is observed. The temperature of the medium rises as the value of the Kirpichev-like number Ki increases. Similar observation is found in the case of Biot like number Bi. The concentration profile decreases as the value of the Luikov number Lu increases. It is also found that Newton-type temperature input offers a faster sublimation rate in comparison to constant and flux-type temperature input. The analytical results obtained in this study show excellent agreement with previous available results. These results provide a comprehensive theoretical and mathematical understanding of sublimation heat/mass transfer and are expected to be useful in energy storage systems, food technology, and accelerated freeze drying. © 2023 Elsevier Ltd
An analytical study of coupled heat and mass transfer freeze-drying with convection in a porous half body: A moving boundary problem
(Elsevier Ltd, 2022) Vikas Chaurasiya; Jitendra Singh
The freeze-drying of a porous body is the most commonly used process in food technology to capture the coupled heat and mass transfer phenomena which appears in a class of moving boundary problem. The modern technology demand encourages investigators to provide techniques for accelerated food drying (AFD) and preservation of material to be denatured. Experimental study of freeze-drying of a porous body may be difficult and exploration of robust theoretical models with convection is critical. Further, the problem concerning in coupled heat and mass transfer, there is lack of mathematical analysis in the previous literatures which does not accounts the convective heat and mass transfer, convective term due to water vapour and condition for the limitation of sublimation and desorption. It is therefore, essential to develop mathematical formulation to discuss these type of freeze-drying phase change processes. In the current paper, the mathematical work is devoted to study a coupled heat and mass transfer problem describing freeze-drying of a material in a porous half-space. The problem accounts convection in porous frozen, sublimated and desorbed regions and a convective term due to moisture flow of the water vapour in the sublimated region. The exact solution of the proposed problem is obtained via similarity transformation. Condition for the limitation of sublimation and desorption is obtained and illustrated graphically. The effect of various parameters on thermal properties is discussed in detailed. The range values of governing problem parameters are taken as: 0 to 2 for Pe, 0.01 to 1.0 for β, 0.1 to 0.9 for α21, 0.1 to 2.1 for γ1, 0.5 to 2.0 for γ3, 0.2 to 0.8 for ω, 0.01 to 0.85 for (ϵ ‐ ω), 0 to 50 for v and 0.21 to 1.65 for ϵ. In current work, it is shown that the freeze-drying process becomes faster in the presence of convection rather than in the absence of convection. Furthermore, the rate of water vaporization from the surface of the porous body enhanced, as a result freeze-drying process deterred. The current work may be expected aid in accelerated freeze drying (AFD) technology. © 2022 Elsevier Ltd
An analytical study on sublimation process in the presence of convection effect with heat and mass transfer in porous medium
(Elsevier Ltd, 2022) Jitendra; K.N. Rai; Jitendra Singh
The mathematical study of one dimensional heat and mass transfer phenomena is investigated. A Stefan like phenomena is defined as a heat and mass transfer problem with presence of convection in vapour region for heat and moisture flow and convective term due to mass transfer of the water vapour in frozen region. The sublimation process considered in two region: (i) In frozen region, s(t)< x < ∞, there is no effect of moisture in this region. (ii) In vapour region, 0 < x < s(t), there is an effect of heat and moisture flows. The thermo-physical properties of each region are constant, but may be differ for different region. The analytical solutions are obtained for the temperature and moisture profile and moving sublimation interface by using the similarity transformation procedure. The effect of some parameters included in the sublimation process with various enclosures, i.e. dimensionless quantity l0, Peclet number Pe, Luikov number Lu, KT, a21 and other constant parameters are comprehensively investigated and represented graphically. © 2021 Elsevier Ltd
An exact Analysis of Melting Phenomena Based on Non-Classical Heat Equation with Moving Boundary Problem: Application of Melting-Freezing
(Pleiades Publishing, 2024) Jitendra; K.N. Rai; Jitendra Singh
Abstract: Purpose: The purpose of this study is to introduce a melting phenomena based non-classical heat equation with latent heat as a function of the moving interface and its velocity, which has not often been taken into consideration previously in the literature available due to the non-linearity of the interface condition. In view of these problems, three mathematical models are proposed for non-classical moving boundary problems including both conduction and convection effects. The applied heat flux on the surface is subjected to a control function at x = 0. In a certain situation, latent heat varies with moving interface and its velocity, and in another, latent heat may be treated as constant. Design/methodology: In the context of non-linear variable latent heat, we provided an analytical analysis for single-phase and double-phase moving boundary problems. The similarity transformation approach has been used to obtain analytical results. The impact of associated problem parameters are discussed in detail. Findings: From this study, it is observed that in the case of variable latent heat, moving interface get accelerated more in comparison to constant latent heat. Furthermore, when the Peclet number and the value of the coefficient of control function increase then the melting process become enhanced. In the present study, convection plays a key role during the melting process. This study may improve the theoretical and mathematical understanding of a shoreline problem and is applicable in geology and thermal management systems. © Pleiades Publishing, Ltd. 2024.
Analysis of nonlinear heat transfer model in multi-layered tissues containing a liver tumor during magnetic fluid hyperthermia
(Springer Science and Business Media B.V., 2025) Faishal Ansari; Jitendra Singh
Magnetic fluid hyperthermia (MFH) is a very effective and less invasive treatment method for healing various tumors. Due to the intense heterogeneity and complexity of living tissue, we have considered blood perfusion and thermal conductivity as temperature-dependent. This study examines the behavior of temperature patterns in sphere-shaped living tissues during MFH treatment by using the nonlinear bioheat model that accounts the influence of key variables on heating behavior. Because of its nonlinearity, this problem is simulated using a combination of bvp4c and finite difference methods. This numerical technique is validated by comparing its findings with an analytical solution in a particular case, and it is seen that the outcomes generated from both methods showed a significant level of resemblance. Further, we conducted a comparison between the outcomes of our model and the experimental results, which confirms the reliability of the present nonlinear model. The findings of our study indicate that the temperature-dependent blood perfusion rate and thermal conductivity significantly influence the temperature within tumor area, but have minimal impact on the temperature in the surrounding region during MFH therapy. Further analysis reveals that the influence of quadratically temperature-dependent thermal conductivity is more significant compared to the linearly temperature-dependent forms of thermal conductivity. Additionally, the radius of nanoparticles and magnetic field intensity play a critical role in attaining hyperthermia temperature within the tumor area. © Akadémiai Kiadó Zrt 2025.