Theoretical analysis of thermal processes in living biological tissue under local hyperthermia. II. Analysis of temperature fields in local SHF hyperthermia with regard for nonstationary nonlinear tissue perfusion

1996 ◽  
Vol 68 (3) ◽  
pp. 367-373
Author(s):  
Z. P. Shul'man ◽  
B. M. Khusid ◽  
I. V. Fain
Keyword(s):  
Theoretical Analysis ◽  
Biological Tissue ◽  
Tissue Perfusion ◽  
Temperature Fields ◽  
Thermal Processes ◽  
Local Hyperthermia

scholarly journals Numerical model of biological tissue heating using the models of bio–heat transfer with delays

2019 ◽  
Vol 128 ◽  
pp. 02002
Author(s):  
Ewa Majchrzak ◽  
Bohdan Mochnacki
Keyword(s):  
Numerical Model ◽  
Biological Tissue ◽  
Classical Model ◽  
Thermal Processes ◽  
Phase Lag ◽  
Dual Phase ◽  
Thermalization Time ◽  
External Heat Source ◽  
Order Form ◽  
Tissue Heating

The numerical model of thermal processes in domain of biological tissue subjected to an external heat source is discussed. The model presented is based on the second order dual–phase–lag equation (DPLE) in which the relaxation time and thermalization time thermalization time (τq and τT) are tak n into account. In this paper the homogeneous, cylindrical skin tissue domain is considered. The most important aim of the research is to compare the results obtained using the classical model (the first-orderDPLE) with the numerical solution resulting from the higher order form of this equation. At the stage of numerical computations the Finite Difference Method (FDM) is applied. In the final part of the paper the examples of computations are shown.

scholarly journals Energy efficiency of temperature distribution in electromagnetic welding of rolling stock parts

2019 ◽  
Vol 110 ◽  
pp. 01017 ◽  
Author(s):  
Andrew Lyudagovsky ◽  
Alexey Loktev ◽  
Vadim Korolev ◽  
Irina Shishkina ◽  
Diana Alexandrova ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Temperature Distribution ◽  
Lateral Surface ◽  
Temperature Fields ◽  
Rolling Stock ◽  
Infinite Cylinder ◽  
Thermal Processes ◽  
First Approximation ◽  
Constant Source

When modeling temperature fields in details of different geometry on the basis of the obtained calculations, the graphs of temperature dependence on the power of the source and the thickness of the deposited layer, non-contact measurement of temperatures in the working area and the sub-sequent calculation of temperature fields allow describing the thermal processes in the electromagnetic surfacing in the first approximation. The determination of temperatures should be carried out taking into account the accumulation of heat by an infinite cylinder with a constant source evenly distributed over its lateral surface.

scholarly journals Electromagnetic and thermal processes in invertors for the coagulation of biological tissue

2015 ◽  
Vol 20 (2) ◽  
Author(s):  
Евгений Дмитриевич Дзюба ◽  
В. В. Перекрест
Keyword(s):  
Biological Tissue ◽  
Thermal Processes

scholarly journals Experience in modeling a comfortable environment in the transport compartment

2020 ◽  
Vol 157 ◽  
pp. 01019
Author(s):  
Vladimir Pankratov ◽  
Alexey Golikov ◽  
Elena Pankratova ◽  
Marina Barulina ◽  
Sofiya Galkina
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Thermal Processes ◽  
Passenger Compartment ◽  
The Public ◽  
Actual Operating ◽  
Specific Proposal ◽  
Series Of Experiments ◽  
The Mathematical Model

The theoretical base was developed and the mathematical model of dynamic thermal processes in a compartment of public transport was constructed. The software which is realized the constructed mathematical model was developed. The mathematical model provides for the possibility of taking into account the most possible environmental conditions which can have place in the actual operating conditions of a transport even the angle of illumination - the current temperature of the external environment, the presence of solar radiation taking into account the angle of sun’s illumination, and the temperature of the roadway. The software allows calculation and visualization non –stationary temperature fields in the public transport’s compartments using the example of a trolley bus. For a specific trolley bus design, a series of experiments to calculate the comfortable temperature for passengers were conducted, These experiments are showed the performance of the constructed model and allowed to formulate a specific proposal for improving the thermoregulation system of the trolleybus’ passenger compartment.

Numerical Simulation of the Thermal Fields Occurring in the Treatment of Malignant Tumors by Local Hyperthermia

1993 ◽  
Vol 115 (3) ◽  
pp. 247-253 ◽  
Author(s):  
K. T. O’Brien ◽  
A. M. Mekkaoui
Keyword(s):  
Heat Transfer ◽  
Transient Flow ◽  
Malignant Tumors ◽  
Blood Perfusion ◽  
Temperature Fields ◽  
Conductive Heat ◽  
Transient Heating ◽  
Local Hyperthermia ◽  
Thermal Fields ◽  
Dual Beam

Dual beam microwave heating is known to deposit heat at depth in a medium. Thus transient heating times may be reduced and more even heating may be obtained. Such a system has potential in the treatment of cancer by hyperthermia. A theoretical analysis of this situation is presented here. A simulation has been made of the thermal fields generated in the treatment of malignant tumors using local hyperthermia. The simulation utilizes the alternating direction implicit method which is particularly suited to the solution of the governing equations, and provides rapid convergence in multiple dimensions. The simulation is three dimensional in temperature, with variations occurring through two spatial coordinates and one time coordinate. The simulation can accommodate the transient flow of heat due to conductive heat transfer through tissues such as healthy tissue, malignant tumors, cartilage and bone, convective heat transfer through perfusion in the tissue and flow through the arteries, and heat generation from sources such as microwave beams. Small changes in the thermophysical properties of the tissue, and the blood perfusion rates are shown to exhibit only minor effects on the thermal fields, whereas the power of the heat sources, and the conductive flux are shown to have major effects on the thermal fields. The effects of adjacent physiological structures such as arteries and bones have also been determined. The temperature fields have been found to be weakly dependent on the increased perfusion rates encountered in the arteries except when the perfusion rate in the artery exceeds that in the tissue by at least one order of magnitude. A similar effect is noticed if the tumor is close to a bone. The greater thermal insulation exhibited by the bone restricts the flow of heat into it, and therefore causes the tissue to increase in temperature. Once the transient heating has been employed and the heating proceeds under steady-state conditions, the dual beam microwave applicator must be controlled to avoid overheating. The effect of on/off control and proportional + integral + derivative control is discussed.

Sign in / Sign up

Export Citation Format

Share Document