Effects of Nonuniform Tissue Properties on Temperature Prediction in Magnetic Nanohyperthermia

2011 ◽  
Vol 2 (2) ◽  
Author(s):  
Qian Wang ◽  
Zhong-Shan Deng ◽  
Jing Liu
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Cooling Water ◽  
Blood Perfusion ◽  
Source Distribution ◽  
Surface Cooling ◽  
Temperature Prediction ◽  
Tissue Properties ◽  
Distribution Features ◽  
Em Field

In tumor hyperthermia, effectively planning in advance and thus controlling in situ the heating dosage within the target region are rather critical for the success of a therapy. Many studies have simulated the temperature distribution during hyperthermia. However, most of them are based on fixed and known heat source distributions, which are generally very complex to compute. Besides, there is little information concerned the numerical analysis of temperature during magnetic hyperthermia loading with magnetic nanoparticles (MNPs), which has its specific heat source distribution features. Particularly, the parameters for different human tissues varied very much, which will cause a serious impact on the heat source and temperature distribution. This paper is aimed at investigating the effects of nonuniform tissue properties to the temperature prediction in magnetic nanohyperthermia and other possible effect factors including external EM field, MNP properties, tumor size and depth, surface cooling conditions, etc. It was found that the spatial heat source generated in the nonuniform model appears smaller than that in the uniform model. This is mainly resulted from the energy reflection when transmitting from fat to tumor and muscle under the same condition, while the temperature is higher on account of overall contribution of different parameters including tissue thermal conductivity, blood perfusion, density, heat capacity, and metabolic heat production rate, which also affect the temperature distribution apart from the heat source. Controlling the properties of the external EM field, MNPs and cooling water can acquire different temperature distributions. Tumors with different depths and sizes need specific plannings, which require as accurate as possible temperature prediction. The nonuniform model can be further improved to be applied in magnetic nanohyperthermia treatment planning and thus help optimize the surgical procedures.

scholarly journals Thermal optimization of a 3-D integrated circuit

2020 ◽  
Vol 24 (4) ◽  
pp. 2615-2620
Author(s):  
Kang-Jia Wang ◽  
Chu-Xia Hua ◽  
Yan-Hong Liang
Keyword(s):  
Temperature Distribution ◽  
Optimal Design ◽  
Heat Source ◽  
Integrated Circuit ◽  
Numerical Approach ◽  
Source Distribution ◽  
Thermal Optimization ◽  
Optimal Heat ◽  
Heat Source Distribution

In a 3-D integrated circuit the heat source distribution has a huge effect on the temperature distribution, so an optimal heat source distribution is needed. This paper gives a numerical approach to its thermal optimization, the result can be used for 3-D integrated circuit optimal design.

scholarly journals Assessing Heavy Industrial Heat Source Distribution in China Using Real-Time VIIRS Active Fire/Hotspot Data

2018 ◽  
Vol 10 (12) ◽  
pp. 4419 ◽  
Author(s):  
Caihong Ma ◽  
Jin Yang ◽  
Fu Chen ◽  
Yan Ma ◽  
Jianbo Liu ◽  
...  
Keyword(s):  
Economic Development ◽  
Heat Source ◽  
Infrared Imaging ◽  
Mainland China ◽  
Processing System ◽  
Source Distribution ◽  
Heavy Industry ◽  
Rapid Urbanization ◽  
Active Fire ◽  
Heat Source Distribution

Rapid urbanization and economic development have led to the development of heavy industry and structural re-equalization in mainland China. This has resulted in scattered and disorderly layouts becoming prominent in the region. Furthermore, economic development has exacerbated pressures on regional resources and the environment and has threatened sustainable and coordinated development in the region. The NASA Land Science Investigator Processing System (Land-SIPS) Visible Infrared Imaging Radiometer (VIIRS) 375-m active fire product (VNP14IMG) was selected from the Fire Information for Resource Management System (FIRMS) to study the spatiotemporal patterns of heavy industry development. Furthermore, we employed an improved adaptive K-means algorithm to realize the spatial segmentation of long-order VNP14IMG and constructed heat source objects. Lastly, we used a threshold recognition model to identify heavy industry objects from normal heat source objects. Results suggest that the method is an accurate and effective way to monitor heat sources generated from heavy industry. Moreover, some conclusions about heavy industrial heat source distribution in mainland China at different scales were obtained. Those can be beneficial for policy-makers and heavy industry regulation.

scholarly journals Understanding the thermal problem of variable gradient functionally graded plate based on hybrid numerical method under linear heat source

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110178
Author(s):  
Jianhui Tian ◽  
Guoquan Jing ◽  
Xingben Han ◽  
Guangchu Hu ◽  
Shilin Huo
Keyword(s):  
Heat Conduction ◽  
Temperature Distribution ◽  
Heat Source ◽  
Numerical Method ◽  
Functionally Graded ◽  
Thermal Problem ◽  
Linear Heat ◽  
Hybrid Numerical Method ◽  
Linear Heat Source ◽  
Gradient Parameter

The thermal problem of functionally graded materials (FGM) under linear heat source is studied by a hybrid numerical method. The accuracy of the analytical method and the efficiency of the finite element method are taken into account. The volume fraction of FGM in the thickness direction can be changed by changing the gradient parameters. Based on the weighted residual method, the heat conduction equation under the third boundary condition is established. The temperature distribution of FGM under the action of linear heat source is obtained by Fourier transform. The results show that the closer to the heat source it is, the greater the influence of the heat source is and the influence of the heat source is local. The temperature change trend of the observation points is consistent with the heat source, showing a linear change. The results also show that the higher the value of gradient parameter is, the higher the temperature of location point is. The temperature distribution of observation points is positively correlated with gradient parameter. When the gradient parameter value exceeds a certain value, it has a little effect on the temperature change in the model and the heat conduction in the model tends to be pure metal heat conduction, the optimal gradient parameters combined the thermal insulation property of ceramics and the high strength toughness of metals are obtained.

A Simplified Numerical Approach for Finding the Temperature Distribution in Submerged arc Welding Process

2012 ◽  
Vol 622-623 ◽  
pp. 315-318
Author(s):  
Aparesh Datta ◽  
Subodh Debbarma ◽  
Subhash Chandra Saha
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Arc Welding ◽  
Welding Process ◽  
Numerical Approach ◽  
High Heat ◽  
Submerged Arc Welding ◽  
Fusion Welding ◽  
Arc Welding Process ◽  
Submerged Arc

The quality of joining has assumed a greater role in fabrication of metal in recent years, because of the development of new alloys with tremendously increased strength and toughness. Submerged arc welding is a high heat input fusion welding process in which weld is produced by moving localized heat source along the joint. The weld quality in turn affected by thermal cycle that the weldment experiences during the welding. In the present study a simple comprehensive mathematical model has been developed using a moving heat source and analyzing the temperature on one section and then the temperature distribution of other section are correlated with time delay with reference analyzed section.

Characterization of the Focal Cooling Necessary to Suppress Spontaneous Epileptiform Activity

2007 ◽  
Author(s):  
Reynaldo G. Guerra ◽  
Van Carey ◽  
Boris Rubinsky ◽  
Mitchel Berger
Keyword(s):  
Penetration Depth ◽  
Epileptiform Activity ◽  
Intractable Epilepsy ◽  
Blood Perfusion ◽  
Thermal Parameters ◽  
Heat Transfer Analysis ◽  
Brain Response ◽  
Surface Cooling ◽  
Cold Saline ◽  
Focal Cooling

It has been established that focal cooling to suppress epileptiform activity has become a real and viable option. However, the specific thermal parameters necessary to suppress epileptiform activity have only begun to be quantitatively defined. In 2002 it was reported that a 41 year-old man with medically intractable epilepsy undertook surgery to remove his tumor and resect adjacent epileptogenic tissue. Electrocorticography was performed before resection. Cold saline was impinged on the resulting interictal spike foci resulting in transient, complete cessation of spiking. We present a transient post-operative heat transfer analysis of the cold saline impingement on the surface of brain. An approximate temporal and spatial temperature distribution of the perfused human brain response to surface cooling was developed. The realistic extent of cooling below the brain surface due to impinging saline was quantified. The sensitivity of cooling penetration depth to (a) saline exit velocity from the syringe, and (b) syringe inside diameter, was evaluated. A parametric study was performed to characterize the effects of brain metabolism and blood perfusion on surface cooling. The required thermal parameters necessary to suppress epileptiform activity through focal cooling are here quantitatively approximated, i.e. heat flux removal and maximum and realistic cooling penetration depths. The relatively shallow penetration depth suggests that the spreading depolarization associated with epileptiform activity may be abolished through focal cooling without affecting the deeper neurons responsible for motor activity.

scholarly journals Plane Strain Deformation In A Thermoelastic Microelongated Solid With Internal Heat Source

2015 ◽  
Vol 20 (4) ◽  
pp. 717-731
Author(s):  
P. Ailawalia ◽  
S.K. Sachdeva ◽  
D.S. Pathania
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Normal Mode Analysis ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Displacement Component ◽  
Mode Analysis ◽  
Plane Strain Deformation ◽  
Gl Theory ◽  
Component Force

Abstract The purpose of this paper is to study the two dimensional deformation due to an internal heat source in a thermoelastic microelongated solid. A mechanical force is applied along an overlaying elastic layer of thickness h. The normal mode analysis has been applied to obtain the exact expressions for the displacement component, force stress, temperature distribution and microelongation. The effect of the internal heat source on the displacement component, force stress, temperature distribution and microelongation has been depicted graphically for Green-Lindsay (GL) theory of thermoelasticity.

scholarly journals Experimental study of heat transfer through cooling water circuit in a reactor vault by using Al2O3 nano fluid

2018 ◽  
Vol 22 (2) ◽  
pp. 1149-1161 ◽  
Author(s):  
Maria Anish ◽  
Balakrishnan Kanimozh
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Base Fluid ◽  
Nuclear Reactor ◽  
Characteristic Curve ◽  
Reactor Core ◽  
Cooling Water ◽  
Heat Transfer Process ◽  
Nano Fluid ◽  
Al2o3 Nanoparticle

The heat produced in the nuclear reactor due to fission reaction must be kept in control or else it will damage the components in the reactor core. Nuclear plants are using water for the operation dissipation of heat. Instead, some chemical substances which have higher heat transfer coefficient and high thermal conductivity. This experiment aims to find out how efficiently a nanofluid can dissipate heat from the reactor vault. The most commonly used nanofluid is Al2O3 nanoparticle with water or ethylene as base fluid. The Al2O3 has good thermal property and it is easily available. In addition, it can be stabilized in various PH levels. The nanofluid is fed into the reactor?s coolant circuit. The various temperature distribution leads to different characteristic curve that occurs on various valve condition leading to a detailed study on how temperature distribution carries throughout the cooling circuit. As a combination of Al2O3 as a nanoparticle and therminol 55 as base fluid are used for the heat transfer process. The Al2O3 nanoparticle is mixed in therminol 55 at 0.05 vol.% concentration. Numerical analysis on the reactor vault model was carried out by using ABAQUS and the experimental results were compared with numerical results.

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