SEMINUMERICAL MODEL TO STUDY TEMPERATURE DISTRIBUTION IN PERIPHERAL LAYERS OF ELLIPTICAL AND TAPERED SHAPED HUMAN LIMBS

2010 ◽  
Vol 10 (01) ◽  
pp. 57-72 ◽  
Author(s):  
MAMTA AGRAWAL ◽  
NEERU ADLAKHA ◽  
KAMALRAJ PARDASANI
Keyword(s):  
Temperature Distribution ◽  
Three Dimensional ◽  
Axial Direction ◽  
Temperature Profiles ◽  
Series Method ◽  
The Finite Element Method ◽  
Biophysical Parameters ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
Fourier Series Method

In this article, a seminumerical approach has been developed to study temperature distribution in peripheral layers of tapered shaped human limbs, which are elliptical in shape. The model is three-dimensional which incorporates the important biophysical parameters such as blood mass flow rate, thermal conductivity and rate of metabolic heat generation. Appropriate boundary conditions have been framed using biophysical conditions. The finite element method has been employed along radial and angular directions and Fourier series method along axial direction to obtain temperature profiles in the region. The results have been used to study relationships among various physical and physiological parameters. MATLAB 7.0 has been used to simulate the model and obtain numerical results.

Initial design of low-thrust trajectories based on the Bezier curve-based shaping approach

2020 ◽  
Vol 234 (11) ◽  
pp. 1825-1835
Author(s):  
Zichen Fan ◽  
Mingying Huo ◽  
Naiming Qi ◽  
Ce Zhao ◽  
Ze Yu ◽  
...  
Keyword(s):  
Fourier Series ◽  
Three Dimensional ◽  
Initial Approximation ◽  
Mission Design ◽  
Bézier Curve ◽  
Design Stage ◽  
Bezier Curve ◽  
Series Method ◽  
Low Thrust ◽  
Fourier Series Method

This paper presents a method to use the Bezier curve to rapidly generate three-dimensional low-thrust trajectories, which can provide a suitable initial approximation to be used for more accurate trajectory optimal control tools. Two missions, from Earth to Mars and the asteroid Dionysus, are considered to evaluate the performance of the method. In order to verify the advantages of this method, it is compared with the finite Fourier series method. Numerical results show that the Bezier method can get better performance index in shorter computation time compared with the finite Fourier series method. The applicability of the solution obtained by Bezier method is evaluated by introducing the obtained solution into the Gauss pseudospectral method as an initial guess. The simulation results show that the Bezier method can rapidly generate a very suitable three-dimensional initial trajectory for the optimal solver. This is very important for rapid evaluation of the feasibility of a large number of low-thrust flight schemes in the preliminary mission design stage.

Temperature profiles with respect to inhomogeneity and geometry of the human body

1988 ◽  
Vol 65 (3) ◽  
pp. 1110-1118 ◽  
Author(s):  
J. Werner ◽  
M. Buse
Keyword(s):  
Human Body ◽  
Three Dimensional ◽  
The Body ◽  
Physiological Data ◽  
Physical Parameters ◽  
Temperature Profiles ◽  
Metabolic Heat ◽  
Spatially Distributed ◽  
Adequate Representation ◽  
Neutral Conditions

Temperature profiles within the human body are highly dependent on the geometry and inhomogeneity of the body. Physical parameters such as density and heat conductivity of the various tissues and variables such as blood flow and metabolic heat production of different organs are spatially distributed and thereby influence the temperature profiles within the human body. Actual physiological knowledge allows one to take into account up to 54 different spatially distributed values for each parameter. An adequate representation of the anatomy of the body requires a spatial three-dimensional grid of at least 0.5-1.0 cm. This is achieved by photogrammetric treatment of three-dimensional anatomic models of the human body. As a first essential result, the simulation system has produced a realistic picture of the topography of temperatures under neutral conditions. Compatibility of reality and simulation was achieved solely on the basis of physical considerations and physiological data base. Therefore the simulation is suited to the extrapolation of temperature profiles that cannot be obtained experimentally.

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.

Thermal Math Modeling and Analysis of an Electronic Assembly

2000 ◽  
Vol 123 (4) ◽  
pp. 372-378 ◽  
Author(s):  
K. N. Shukla
Keyword(s):  
Temperature Distribution ◽  
Integral Transform ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Circuit Board ◽  
Heat Sources ◽  
The Finite Element Method ◽  
Modeling And Analysis ◽  
Discrete Surface ◽  
Integral Transform Technique

This paper presents a mathematical model for a three-dimensional thermal analysis of a circuit board with multiple heat dissipating sources. The model considers the three-dimensional flat plate with discrete surface heat sources and integral transform technique is employed to determine the temperature distribution. The calculation procedure for the thermal characteristics of a circuit board, with surface mounted components, is presented and the solution is compared with those obtained from the finite element method. Also, the temperature distribution of a two-layered circuit board is presented in terms of Green’s function.

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

An Inverse Method for Controlling the Temperature Distribution and Identification of the Conductivity of Thick Cylindrical Shells

2011 ◽  
Author(s):  
Hossein Rastgoftar ◽  
Faissal A. Moslehy
Keyword(s):  
Temperature Distribution ◽  
Heat Conduction Equation ◽  
Inverse Method ◽  
Cylindrical Shells ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Heat Diffusion ◽  
The Finite Element Method ◽  
Steady State Heat ◽  
Boundary Surfaces

The paper presents an inverse method for control of temperature distribution in thick cylindrical shells. Since the thickness is large enough, three-dimensional heat diffusion equations must be considered. To control the temperature distribution, the heat fluxes at the boundary surfaces of the cylindrical shell are assigned values such that the desired temperature distribution, which satisfies the steady state heat conduction equation, will be achieved. Furthermore, a Lyapunov-based method for identification of the conductivity of the cylinder is presented, and the estimated conductivity is updated such that it converges to the exact value. The numerical results are obtained by the finite element method (FEM), which include the heat flux at the surfaces of the cylinder. These results are shown to be in excellent agreement with the analytical solution.

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.

Three-Dimensional Reconstruction of Two Forms of the Chaperonin GRO EL

1990 ◽  
Vol 48 (1) ◽  
pp. 258-259
Author(s):  
J.L. Carrascosa ◽  
G. Abella ◽  
S. Marco ◽  
M. Muyal ◽  
J.M. Carazo
Keyword(s):  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Series Method ◽  
Three Dimensional Reconstruction ◽  
Structural Components ◽  
E Coli ◽  
Dimensional Reconstruction ◽  
Morphogenetic Factors ◽  
Tilt Series

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.

Sign in / Sign up

Export Citation Format

Share Document