Estimation of overall heat transfer coefficient of cooling system in RF capacitive hyperthermia
The 
study presented in this article involves the estimation of the overall heat 
transfer coefficient of cooling system in RF capacitive hyperthermia 
treatment using inverse problem based on the conjugate gradient method to 
provide improved distribution of temperature. The temperature data computed 
numerically from the direct problem using the finite difference time domain 
method are used to simulate the temperature measurements. The effects of the 
errors and sensor positions upon the precision of the estimated results are 
also considered. The results show that a reasonable estimation of the unknown 
can be obtained. Finally, measurements in a tissue-equivalent phantom are 
employed to appraise the reliability of the presented method. The comparison of 
computed data with measurements shows a good agreement between numerical 
and experimental results.
STUDY OF WATER BOLUS EFFECT ON SAR PENETRATION DEPTH AND EFFECTIVE FIELD SIZE FOR LOCAL HYPERTHERMIA
Water bolus is used in microwave hyperthermia of cancer treatment to control the body surface temperature. In this paper the effect of water bolus on SAR distribution is investigated in the muscle layer of a three layered tissue model. Both the SAR penetration depth and the effective field size (EFS) are computed and compared in presence and in absence of the water bolus. Results are provided for distilled and fresh water with three different thicknesses of water bolus. All numerical simulations are performed using the Ansoft HFSS software. Numerical simulation results are in good agreement with published results.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.