TEMPERATURE DISTRIBUTION AND THERMAL DAMAGE OF PERIPHERAL TISSUE IN HUMAN LIMBS DURING HEAT STRESS: A MATHEMATICAL MODEL

2016 ◽  
Vol 16 (05) ◽  
pp. 1650064 ◽  
Author(s):  
MIR AIJAZ ◽  
M. A. KHANDAY
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Thermal Damage ◽  
Subcutaneous Tissue ◽  
The Body ◽  
Bioheat Equation ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
Living Tissues

The physiological processes taking place in human body are disturbed by the abnormal changes in climate. The changes in environmental temperature are not effective only to compete with thermal stability of the system but also in the development of thermal injuries at the skin surfaces. Therefore, it is of great importance to estimate the temperature distribution and thermal damage in human peripherals at extreme temperatures. In this paper, the epidermis, dermis and subcutaneous tissue were modeled as uniform elements with distinct thermal properties. The bioheat equation with appropriate boundary conditions has been used to estimate the temperature profiles at the nodal points of the skin and subcutaneous tissue with variable ambient heat and metabolic activities. The model has been solved by variational finite element method and the results of the changes in temperature distribution of the body and the damage to the exposed living tissues has been interpreted graphically in relation with various atmospheric temperatures and rate of metabolic heat generation. By involving the metabolic heat generation term in bioheat equation and using the finite element approach the results obtained in this paper are more reasonable and appropriate than the results developed by Moritz and Henriques, Diller and Hayes, and Jiang et al.

scholarly journals A Study on the Effect of Metabolic Heat Generation on Biological Tissue Freezing

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Sonalika Singh ◽  
Sushil Kumar
Keyword(s):  
Temperature Profile ◽  
Heat Generation ◽  
Biological Tissue ◽  
Biological Tissues ◽  
Bioheat Equation ◽  
Metabolic Heat ◽  
Metabolic Heat Generation

The effect of metabolic heat generation on the freezing of biological tissue has been studied. Quasi-steady approximation is used to solve the Pennes bioheat equation in tissues. Temperature profile and motion of freezing interfaces are obtained for different values of metabolic heat generation. It is observed that metabolism has a significant effect on freezing of biological tissues during cryosurgery.

scholarly journals Thermoregulation through Skin at Low Atmospheric Temperatures

1970 ◽  
Vol 5 (1) ◽  
pp. 14-22 ◽  
Author(s):  
DB Gurung
Keyword(s):  
Exact Solution ◽  
Temperature Distribution ◽  
Subcutaneous Tissue ◽  
One Dimensional ◽  
Physiological Conditions ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
Engineering And Technology ◽  
Key Words Thermoregulation ◽  
2000 Mathematics Subject Classification

The metabolic heat generation decreases exponentially if the persistence of cooling in human body is sustained. This phenomena is under consideration in dermis and subcutaneous tissue to study the exact solution of temperature distribution in dermal layers at low atmospheric temperatures. Other suitable variable physiological conditions are taken and the solution has been obtained using laplace tranform in one dimensional case. Key words: Thermoregulation; Human dermal part; Laplace transform. 2000 Mathematics Subject Classification: 92 C 35.   DOI: 10.3126/kuset.v5i1.2843 Kathmandu University Journal of Science, Engineering and Technology Vol.5, No.1, January 2009, pp 14-22

scholarly journals Modelling and investigation of temperature field in the boundary layer of biological bodies

2017 ◽  
pp. 90-99
Author(s):  
Bogdan Khapko
Keyword(s):  
Boundary Layer ◽  
Integral Equation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Transfer Problem ◽  
Blood Perfusion ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
Equation Analysis

A problem on finding temperature field in the boundary layer of biological body when blood perfusion coefficient depends on coordinate is solved. Temperature distribution is caused by the temperature differences between the inside and outside of a body and by the outside heat sources and metabolic heat generation. Heat transfer problem is formulated by using generalized Heaviside functions. Applying the variation of constants method this problem is reduced to the Fredholm integral equation of the second kind. Numerical method of Simpson quadratures was used to solve integral equation. Analysis of temperature distribution in the boundary layer for some cases of boundary conditions is performed. Dependence on temperature inside body from metabolic heat generation and outside heat source is analyzed.

Effect of Physiological Parameters on the Temperature Distribution of a Layered Head Model

2002 ◽  
Author(s):  
Obdulia Ley ◽  
Yildiz Bayazitoglu
Keyword(s):  
Blood Flow ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Brain Temperature ◽  
Blood Perfusion ◽  
Physiological Parameters ◽  
Head Model ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
The Brain

Brain temperature control is important in clinical therapy, because moderate temperature reduction of brain temperature increases the survival rate after head trauma. A factor that affects the brain temperature distribution is the cerebral blood flow, which is controlled by autoregulatory mechanisms. To improve the existing thermal models of brain, we incorporate the effect of the temperature over the metabolic heat generation, and the regulatory processes that control the cerebral blood perfusion and depend on physiological parameters like, the mean arterial blood pressure, the partial pressure of oxygen, the partial pressure of carbon dioxide, and the cerebral metabolic rate of oxygen consumption. The introduction of these parameters in a thermal model gives information about how specific conditions, such as brain edema, hypoxia, hypercapnia, or hypotension, affect the temperature distribution within the brain. Existing biological thermal models of the human brain, assume constant blood perfusion, and neglect metabolic heat generation or consider it constant, which is a valid assumption for healthy tissue. But during sickness, trauma or under the effect of drugs like anesthetics, the metabolic activity and organ blood flow vary considerably, and such variations must be accounted for in order to achieve accurate thermal modeling. Our work, on a layered head model, shows that variations of the physiological parameters have profound effect on the temperature gradients within the head.

Hysteresis Heating of Railroad Bearing Thermoplastic Elastomer Suspension Element

2017 ◽  
Author(s):  
Oscar O. Rodriguez ◽  
Arturo A. Fuentes ◽  
Constantine Tarawneh ◽  
Robert E. Jones
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Steady State ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Internal Heat ◽  
Thermoplastic Elastomer ◽  
Internal Heat Generation ◽  
Element Analysis ◽  
Railroad Bearing

Thermoplastic elastomers (TPE’s) are increasingly being used in rail service in load damping applications. They are superior to traditional elastomers primarily in their ease of fabrication. Like traditional elastomers they offer benefits including reduction in noise emissions and improved wear resistance in metal components that are in contact with such parts in the railcar suspension system. However, viscoelastic materials, such as the railroad bearing thermoplastic elastomer suspension element (or elastomeric pad), are known to develop self-heating (hysteresis) under cyclic loading, which can lead to undesirable consequences. Quantifying the hysteresis heating of the pad during operation is therefore essential to predict its dynamic response and structural integrity, as well as, to predict and understand the heat transfer paths from bearings into the truck assembly and other contacting components. This study investigates the internal heat generation in the suspension pad and its impact on the complete bearing assembly dynamics and thermal profile. Specifically, this paper presents an experimentally validated finite element thermal model of the elastomeric pad and its internal heat generation. The steady-state and transient-state temperature profiles produced by hysteresis heating of the elastomer pad are developed through a series of experiments and finite element analysis. The hysteresis heating is induced by the internal heat generation, which is a function of the loss modulus, strain, and frequency. Based on previous experimental studies, estimations of internally generated heat were obtained. The calculations show that the internal heat generation is impacted by temperature and frequency. At higher frequencies, the internally generated heat is significantly greater compared to lower frequencies, and at higher temperatures, the internally generated heat is significantly less compared to lower temperatures. However, during service operation, exposure of the suspension pad to higher loading frequencies above 10 Hz is less likely to occur. Therefore, internal heat generation values that have a significant impact on the suspension pad steady-state temperature are less likely to be reached. The commercial software package ALGOR 20.3TM is used to conduct the thermal finite element analysis. Different internal heating scenarios are simulated with the purpose of obtaining the bearing suspension element temperature distribution during normal and abnormal conditions. The results presented in this paper can be used in the future to acquire temperature distribution maps of complete bearing assemblies in service conditions and enable a refined model for the evolution of bearing temperature during operation.

Estimation of the kidney metabolic heat generation rate

2019 ◽  
Vol 35 (9) ◽  
Author(s):  
Helcio R.B. Orlande ◽  
Nelson Afonso Lutaif ◽  
José Antonio Rocha Gontijo
Keyword(s):  
Heat Generation ◽  
Generation Rate ◽  
Heat Generation Rate ◽  
Metabolic Heat ◽  
Metabolic Heat Generation

Two-dimensional finite element model to study temperature distribution in peripheral regions of extended spherical human organs involving uniformly perfused tumors

2015 ◽  
Vol 08 (06) ◽  
pp. 1550074 ◽  
Author(s):  
Akshara Makrariya ◽  
Neeru Adlakha
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Finite Element Model ◽  
Metabolic Activity ◽  
Element Model ◽  
The Body ◽  
Tissue Response ◽  
Two Dimensional ◽  
Human Breast ◽  
Peripheral Regions

Temperature as an indicator of tissue response is widely used in clinical applications. In view of above a problem of temperature distribution in peripheral regions of extended spherical organs of a human body like, human breast involving uniformly perfused tumor is investigated in this paper. The human breast is assumed to be spherical in shape with upper hemisphere projecting out from the trunk of the body and lower hemisphere is considered to be a part of the body core. The outer surface of the breast is assumed to be exposed to the environment from where the heat loss takes place by conduction, convection, radiation and evaporation. The heat transfer from core to the surface takes place by thermal conduction and blood perfusion. Also metabolic activity takes place at different rates in different layers of the breast. An elliptical-shaped tumor is assumed to be present in the dermis region of human breast. A finite element model is developed for a two-dimensional steady state case incorporating the important parameters like blood flow, metabolic activity and thermal conductivity. The triangular ring elements are employed to discretize the region. Appropriate boundary conditions are framed using biophysical conditions. The numerical results are used to study the effect of tumor on temperature distribution in the region.

Experimental and Finite Element Analysis of the Thermal-Electric Process in Monopolar Electrosurgical Thermal Management

2008 ◽  
Author(s):  
Jacob S. Gee ◽  
Robert E. Dodde ◽  
James D. Geiger ◽  
Albert J. Shih
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Thermal Management ◽  
Management System ◽  
Thermal Damage ◽  
Electrical Discharge Machining ◽  
Ex Vivo ◽  
Active Electrode ◽  
Cooling Channels ◽  
Thermal Management System

This study develops a thermal management system for the most commonly used energy-based surgical instrument: the monopolar electrosurgical device. Monopolar electrosurgery, using the same principle as the electrical discharge machining, is widely used to cut or remove tissue by sparks during surgical operations. This study develops a thermal management system consists of cooling channels placed around the active electrode to reduce the thermal damage to the tissue. Finite element modeling (FEM) was performed to analyze temperature distribution in biological tissue subject to heat generation by a commonly used monopolar electrosurgical device. The mathematical model was verified by comparing FEM predicted temperature distribution with experimental measurements. Exvivo experiments were performed with bovine liver tissue heated by a monopolar pencil electrode. The experimental data for 1 mm distance from the electrode is seen to fit within 1% of the predicted temperature values by the FEM simulation. The accuracy of the model decreases at further distances from the electrode. The inaccuracies are believed to be due to unaccounted temperature-dependent thermal conductivity. The addition of the cooling channels shows a reduction of the radial thermal damage of the tissue in both FEM simulations and ex-vivo experimental procedures.

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