scholarly journals Numerical study of the influence of water evaporation on radiofrequency ablation

2013 ◽  
Vol 12 (1) ◽  
pp. 127 ◽  
Author(s):  
Qing Zhu ◽  
Yuanyuan Shen ◽  
Aili Zhang ◽  
Lisa X Xu
Author(s):  
Qing Zhu ◽  
Binbin Ying ◽  
Aili Zhang ◽  
Lisa X. Xu

Radiofrequency (RF) ablation is one of the promising technologies of tumor therapy due to its minimal invasiveness and other advantages. The high frequency alternating electrical current makes movement of the intracellular ions, results in frictional heat inside the tumor tissue and local temperature rising. Temperature of the tissue near the RF electrode increases much faster than the distant part. When it reaches the vapor (boiling) point, excessive evaporation takes place and increases electrical impedance between the electrode and the targeted tissue. This has been a major obstacle for its application. Coolants such as water circulating in the electrodes has been proposed, but as the coolants are only effective on the electrode wall, quick evaporation and correspondent carbonization still exists.


2020 ◽  
Vol 195 ◽  
pp. 01004
Author(s):  
Ali Kolahdooz ◽  
Hamed Sadeghi ◽  
Mohammad Mehdi Ahmadi

Dispersive soils, as one of the main categories of problematic soils, can be found in some parts of the earth, such as the eastern-south of Iran, nearby the Gulf of Oman. One of the most important factors enhancing the dispersive potential is the existence of dissolved salts in the soil water. The main objective of this study is to explore the influence of water salinity on the instability of a railway embankment due to rainfall infiltration. In order to achieve this goal, the embankment resting on a dispersive stratum is numerically modeled and subjected to transient infiltration flow. The effect of dispersion is simplified through variations in the soil-water retention curve with salinity. The measured water retention curves revealed that by omitting the natural salinity in the soil-water, the retention capability of the soil decreases; therefore, the unsaturated hydraulic conductivity of the soil stratum will significantly decline. According to the extensive decrease in the hydraulic conductivity of the desalinated materials, the rainfall cannot infiltrate in the embankment and the rainfall mostly runs off. However, in the saline embankment, the infiltration decreases the soil suction; and consequently, the factor of safety of the railway embankment decreases.


RSC Advances ◽  
2019 ◽  
Vol 9 (59) ◽  
pp. 34465-34471 ◽  
Author(s):  
Xinxing Lin ◽  
Wei Ma ◽  
Lihui Chen ◽  
Liulian Huang ◽  
Hui Wu ◽  
...  

The influence of water evaporation and absorption on the stability of aqueous glycerol marbles was investigated.


2020 ◽  
Vol 330 ◽  
pp. 01033
Author(s):  
Nihel Grich ◽  
Walid Foudhil ◽  
Souad Harmand ◽  
Sadok Ben Jabrallah

Water spraying in exchanger systems is widely used to allow cooling and improving their performance. However, transfers within the spray mixture are difficult to express because the combined mass and heat are transferred between phases, which complicates the design of the spray systems. This article presents a numerical study of the influence of water volume fraction on the distribution of the temperature in a canal. A 2D numerical model of a horizontal channel was generated and the equations governing the continuous phases (air) and the dispersed phase (water) were developed. These equations were solved using Comsol multiphysics. A comparison of the simulation results and those of the experiment reveals an acceptable concordance.


Author(s):  
Sundeep Singh ◽  
Ramjee Repaka

Radiofrequency ablation (RFA) has emerged as an alternative treatment modality for treating various tumors with minimum intervention. The application of RFA in treating breast tumor is still in its infancy stage. Nevertheless, promising results have been obtained while treating early stage localized breast cancer with RFA procedure. The outcome of RFA is tremendously dependent on the precise insertion of the electrode into the geometric center of the tumor. However, there remains plausible chances of inaccuracies in the electrode placement that can result in slight displacement of the electrode tip from the actual desired location during temperature-controlled RFA application. The present numerical study aims at capturing the influence of inaccuracies in electrode placement on the input energy, treatment time and damage to the surrounding healthy tissue during RFA of breast tumor. A thermo-electric analysis has been performed on three-dimensional heterogeneous model of multilayer breast with an embedded early stage spherical tumor of 1.5 cm. The temperature distribution during the RFA has been obtained by solving the coupled electric field equation and Pennes bioheat transfer equation, while the ablation volume has been computed using the Arrhenius cell death model. It has been found that significant variation in the energy consumption, time required for complete tumor necrosis, and the shape of ablation volume among different positions of the electrode considered in this study are prevalent.


2010 ◽  
Vol 68 (4) ◽  
pp. 364-370 ◽  
Author(s):  
M. Huang ◽  
F.C. Lai

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