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The paper reports an experimental study of production and propagation of diverging and converging spherical shock waves. In order to quantitatively observe spherical shock waves and the flow field behind them, an aspheric spherical transparent test section was designed and constructed. This 150 mm inner-diameter aspheric lens shaped test section permits the collimated visualization laser light beam...
In this paper, focusing of a toroidal shock wave propagating from a shock tube of annular cross-section into a cylindrical chamber was investigated numerically with the dispersion- controlled scheme. For CFD validation, the numerical code was first applied to calculate both viscous and inviscid flows at a low Mach number of 1.5, which was compared with the experiment results and got better consistency...
The paper reports results of experiments to estimate the mortality of ocean bottom dwellers, ostracoda, against underwater shock wave exposures. This study is motivated to verify the possible survival of ocean bottom dwellers, foraminifera, from the devastating underwater shock waves induced mass extinction of marine creatures which took place at giant asteroid impact events. Ocean bottom dwellers...
This paper reports a result of experiments for the determination of reliable shock Hugoniot curves of liquids, in particular, at relatively low pressure region, which are needed to perform precise numerical simulations of shock wave/tissue interaction prior to the development of shock wave related therapeutic devices. Underwater shock waves were generated by explosions of laser ignited 10 mg silver...
This paper details how high-voltage pulsed discharge was generated in water with different types of bubbling gases as well as no gas in a reactor with a point-mesh electrode configuration. Acid orange 7 organic dye solution was treated as wastewater sample to elucidate chemical efficiency of bubbling gas types in discharge reactor. Experimental results showed that, oxygen bubbling gas effectively...
Inducing apoptosis in malignant cells and controlling ES cell differentiation using sub-nanosecond high voltage pulses have been investigated. It is important to develop a high-power, high frequency electromagnetic wave focusing system for apoptosis induction in cancer. Nonlinear lumped element transmission lines (NLETL) to generate RF pulses have in recent years gained much attention. Our intention...
A shock wave generated by negative pulsed discharge in pressurized carbon dioxide including supercritical (SC) phase was observed by means of Schlieren method. A negative pulsed voltage with a rise time of 90 ns and half-width of 410 ns was applied to a point electrode. The resulting shock wave, seemingly a multi-layered structure, was able to be confirmed despite the single pulsed voltage. Shock...
This report presents on studying of two kinds of underwater shock waves generated by a compact generator using underwater pulsed electric discharges in saline water and their medical application. The water used in this study is aqueous solutions of sodium chloride which is substitute for application to human tissue, while underwater shock waves can propagate in the tissue with low reflection between...
Shock waves in gases and liquids have been widely studied for several years. However, shock waves in supercritical (SC) fluids have not been adequately studied due to their special characteristics referring to both gas and liquid under high temperature and pressure. We have been considering pulsed power system as an effective way for generation of shock waves in SC phase and high-density mediums....
We visualized and analyzed effects of protecting cover layers during medical application of underwater shock waves. Shock waves can be generated by several methods. In this research, we used short pulse underwater discharges to produce tuned underwater shock waves1. A magnetic pulse compression circuit (MPC) was used as energy source2. Using MPC, we were able to produce nanosecond order pulse discharges...
Shock waves have been used for various scientific, industrial, and medical applications. For example, underwater shock waves have been successfully applied for the fragmentation of urinary stones in urology. Further study on the influence of shock waves to tissues is required to extend medical shock wave application. Shock waves have been shown capable of affecting various cells. However, underwater...
Chemical activity of underwater discharge plasma and air discharge plasma generated in contact with water surface in form of streamer channels propagating along the water surface has been investigated using hydrogen peroxide as chemical probe. Point-to-plane electrode geometry and pulse high voltage of positive polarity generated with magnetic pulse compression (MPC) pulsed power modulator was used...
Shock waves have been used for various scientific, industrial, and medical applications. In particular, underwater shock waves have been successfully applied for the fragmentation of urinary stones in Urology. To extend medical shock wave applications, studies of influence of shock waves on tissues are required. Shock waves have been shown to produce the possibility to affect various cells. However,...
This report presents on studying of two kinds of underwater shock waves generate by a compact generator using underwater pulsed electric discharges in saline water and their medical application. The water used in this study is aqueous solutions of sodium chloride which is substitute for application to human tissue, while underwater shock waves can propagate in the tissue with low reflection between...
Bioelectrics, a branch of scientific research dealing with effects of pulsed power on biological objects, has been advancing during recent years. Application of nanosecond pulsed electric field induces apoptosis to the cancer cell. Burst electromagnetic waves focus on the tumor using an ellipsoidal reflector as an invasive methed. Burst electromagnetic waves were characterized by a high-frequency...
Water treatment using electrical discharge plasma, which can generate various physical and chemical processes, has attracted attention1 to reduce environment load and performance cost. However, there are many factors that influence these processes such as input voltage, pulse repetition rate, electrodes gap distance, water conductivity, pressure, temperature, pulse width and other plasma properties...
Bioelectrics, a branch of scientific research dealing with effects of pulsed power on biological objects, has been advancing during recent years1. Authors had an interest in results of applying sub-nanosecond pulsed electric fields to cancer cells. Application of sub-nanosecond pulsed electric field induces apoptosis to the cancer cell2. So far sub-nanosecond pulsed electric fields have been applied...
Inducing apoptosis in malignant cells and controlling ES cell differentiation using sub-nanosecond high voltage pulses have previously been investigated [1]. Results have stimulated the authors to develop a high-power, high frequency electromagnetic wave focusing system for apoptosis induction in cancer cells.
Pulsed power and Plasma science fields have been studies ele ctrical discharge in water1, 2. Our study aims a fundamental analysis of pulsed electrical discharge in water using a high speed camera. The pulsed power generator makes 40 j/pulse, a nd the high speed camera is able to take 12 photos and minim um exposure time is 5 ns. Water conductivity is 170 uS/cm an d 1.6 uS/cm in experiments.
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