Analysis of Heat Generation Through-Electromagnetic Energy Conversion for Magnetic Hyperthermia Cancer Treatment

Author(s):  
Saleh S. Hayek ◽  
Ching-Jen Chen ◽  
Yousef S. Haik ◽  
Mark H. Weatherspoon

Hyperthermia (HT) is a cancer treatment that utilizes a variety of heating methods to destroy cancerous tumors. A diversity of technical problems still exists regarding HT's different approaches, therapeutic potential, and evidence of effectiveness. The foremost problem is in generating and controlling heat in tumors to target cancer sites. The window of temperature for HT is between 42°C and 45°C, with the literature suggesting 43°C to be the ideal temperature for inducing apoptosis (programmed cell death). Normal cells undergo necrosis at higher temperatures than that of the specified range. To address control problems, various methods have been utilized to localize HT heating and limit its temperatures through various applicators, materials, and procedures. One method has been to implant various materials into the human body to heat tumors, a process known as Magnetic Hyperthermia (MH) as it uses magnetic nanoparticles (NP). This method is particularly useful for sending thermal energy to deep seated tumors by using ferro/ferri magnetic NP that absorb non-ionizing electromagnetic (EM) fields delivered into the human body externally. These NP have been shown to heat surrounding tissue until they reach a Curie temperature (Tc) at which generated heat is minimized (many thermodynamic properties change at Tc, such as dielectric, elastic, optical and thermal properties. Fabricated NP, due to spontaneous polarization, can heat via hysteresis losses under applied EM fields making them candidates for testing in (EM) HT systems. Various ferro- and ferromagnetic materials have been studied extensively by this group (e.g.: Ni-Cu, Ni-Co, Ni-Cr, Er, Ce, Gd, and their alloys, etc.) as candidates for HT due to their production of heat through hysteresis or magnetic spin mechanisms. With the use of these nanoparticle systems, the focus of this paper is to produce analysis of heat generation through electromagnetic energy conversion for magnetic hyperthermia cancer treatment and to investigate the heat transfer and heat generation of magnetic NP due to temperature rise upon application of externally applied AC magnetic field. Both, polarization switching and inhomogenities affect polarization orientation within a crystal. Domain switching occurs in two steps: first, the domain nucleates at critical level of applied EM field; second, the interface between the two domains propagates. Particles moving across the interface transform from one domain type to another, which leads to a release of energy in the form of heat. This, in turn, leads to a temperature rise at the interface.

2018 ◽  
Vol 70 (1) ◽  
pp. 15-22 ◽  
Author(s):  
De-xing Zheng ◽  
Weifang Chen ◽  
Miaomiao Li

Purpose Thermal performances are key factors impacting the operation of angular contact ball bearings. Heat generation and transfer about angular contact ball bearings, however, have not been addressed thoroughly. So far, most researchers only considered the convection effect between bearing housings and air, whereas the cooling/lubrication operation parameters and configuration effect were not taken into account when analyzing the thermal behaviors of bearings. This paper aims to analyze the structural constraints of high-speed spindle, structural features of bearing, heat conduction and convection to study the heat generation and transfer of high-speed angular contact ball bearings. Design/methodology/approach Based on the generalized Ohm’s law, the thermal grid model of angular contact ball bearing of high-speed spindle was first established. Next Gauss–Seidel method was used to solve the equations group by Matlab, and the nodes temperature was calculated. Finally, the bearing temperature rise was tested, and the comparative analysis was made with the simulation results. Findings The results indicate that the simulation results of bearing temperature rise for the proposed model are in better agreement with the test values. So, the thermal grid model established is verified. Originality/value This paper shows an improved model on forecasting temperature rise of high-speed angular contact ball bearings. In modeling, the cooling/lubrication operation parameters and structural constraints are integrated. As a result, the bearing temperature variation can be forecasted more accurately, which may be beneficial to improve bearing operating accuracy and bearing service life.


2021 ◽  
Author(s):  
Soboh Alqeeq ◽  
Olivier Le Contel ◽  
Patrick Canu ◽  
Alessandro Retino ◽  
Thomas Chust ◽  
...  

<p>In the present work, we consider four dipolarization front (DF) events detected by MMS spacecraft in the Earth’s magnetotail during a substorm on 23rd of July 2017 between 16:05 and 17:19 UT. From their ion scale properties, we show that these four DF events embedded in fast Earthward plasma flows have classical signatures with increases of Bz, velocity and temperature and a decrease of density across the DF. We compute and compare current densities obtained from magnetic and particle measurements and analyse the Ohm’s law. Then we describe the wave activity related to these DFs. We investigate energy conversion processes via J.E calculations and estimate the importance of the electromagnetic energy flow by computing the divergence of the Poynting vector. Finally we discuss the electromagnetic energy conservation in the context of these DFs.</p>


1968 ◽  
Vol 8 (04) ◽  
pp. 323-324
Author(s):  
C.H. Kuo

In the underground combustion process, part of the heat generated at the combustion front is carried downstream by convection. Temperature distribution in the combustion process can be obtained by including a delta function for heat generation at the combustion surface. This is similar to the hot-fluid injection model of Lauwerier. The dimensionless temperature in the reservoir, phi T1(x, t), and the overburden, phi T2(x, y, t), are as follows: ..........................................(1) ..........................................(2) The ratio R of the heat-front velocity, u, h, to the combustion front velocity, uc, is one of the most important factors governing the temperature distribution in the pay zone. For cases of ub less than uc, no heat is carried ahead of the combustion front and the temperature at the combustion front remains constant for all times. The fraction of the heat stored between the heat front and the combustion front decreases as the time increases. This is because more of the heat is consumed in heating the formation behind the heat front and in heating the cap and bass rock. A more advantageous condition obtains for uh is greater than uc. For this case, the formation ahead of the combustion front is preheated and the amount of heat in this region increases with time. Therefore, due to heat generation and preheating, the total temperature rise at the combustion front also increases with time. Eq. 1 also shows that the temperature at the combustion front is higher at a given time for a thinner reservoir. This seemingly paradoxical result takes place because the amount paradoxical result takes place because the amount of heat recovered from the overburden and subrock upstream of the combustion front is almost independent of the pay zone thickness. On the other hand, this heat is distributed in the pay zone, which has a heat content directly proportional to the formation thickness b. For thin reservoirs, therefore, the temperature rise in the pay zone due to heat recuperation is higher than that in thick reservoirs. For very thick pay zones (h-oo) there would be no heat recuperation, and consequently the combustion- front temperatures would be lowest. For many cases encountered, uh is smaller than uc. Convective-heat transport. ahead of the combustion front can be achieved by increasing uh to obtain the condition uh, >uc. The wet and partially quenched combustion processes have a similar objective. The temperature at the combustion front, however, decreases as the uh/uc ratio increases. If this temperature should fall below the ignition point, the fire would die out. Consequently, at any point, the fire would die out. Consequently, at any time there exists a maximum ratio of uh/uc for which the formation ahead of the combustion front can be heated to increase oil mobility while combustion is maintained. For the case where the heat front moves faster than the combustion front (uh is greater than uc), the downstream heat efficiency E can be derived by applying the integration method given in Ref. 3. P. 323


2011 ◽  
Vol 268-270 ◽  
pp. 406-411 ◽  
Author(s):  
Ömer Sinan Şahin ◽  
Murat Selek ◽  
Şirzat Kahramanlı

In this study, the temperature rise of composite plates with a hole during fatigue loading was investigated. Woven glass/epoxy composite plates with eight plies were subjected to bending fatigue loading and materials were observed by using a thermal camera during the test. Previous works showed that a heat generation can form due to internal friction and damage formation. Therefore, a thermographic infrared imaging system was used to detect the temperature rise of composite specimens. During the tests, the thermal images of the specimens have been recorded by a thermal camera and then transferred to the image processing program which has been developed by using MATLAB. By using these thermal images, the spot temperatures of the specimen were obtained by using artificial neural networks. The obtained temperatures show local increase at places where the heat generation localized. These regions considered being the probable damage initiation sites. It is shown in this study that most probable damage initiation zones in the woven glass/epoxy composite material can be detected by using infrared thermography (IRT) approach prior to failure.


Nanoscale ◽  
2015 ◽  
Vol 7 (29) ◽  
pp. 12728-12736 ◽  
Author(s):  
Christopher A. Quinto ◽  
Priya Mohindra ◽  
Sheng Tong ◽  
Gang Bao

Superparamagnetic iron oxide nanoparticles optimized with a phospholipid-PEG coating achieve high Doxorubicin loading and heat generation for an enhanced multimodal cancer treatment.


Author(s):  
Roja Esmaeeli ◽  
Ashkan Nazari ◽  
Haniph Aliniagerdroudbari ◽  
Seyed Reza Hashemi ◽  
Muapper Alhadri ◽  
...  

The viscoelastic properties of rubbers play an important role in dynamic applications and are commonly measured and quantified by means of Dynamic Mechanical Analysis (DMA) tests. The rubber properties including the static and dynamic moduli are a function of temperature; and an increase in the temperature leads to a decrease in both moduli of the rubber. Due to the heat generation inside the rubber during the DMA test and the possible change of the rubber properties it is important to quantify the amount of temperature rise in the rubber specimen during the test. In this study, a Finite Element Analysis (FEA) model is used to predict the heat generation and temperature rise during the rubber DMA tests. This model is used to identify the best shape of the specimen to achieve the minimum increase in temperature during the test. The double sandwich shear test and the cyclic compression tests are considered in this study because these two tests are mostly used in industry to predict the rubber viscoelastic properties.


2019 ◽  
Vol 32 (5) ◽  
pp. 1902034 ◽  
Author(s):  
Liang Huang ◽  
Shizhe Lin ◽  
Zisheng Xu ◽  
He Zhou ◽  
Jiangjiang Duan ◽  
...  

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