Papers by Keyword: Underwater Shock Wave

Abstract: The National Institute of Technology, Okinawa College (OkNCT) has developed a food processing machine that generates underwater shock waves through wire electrical discharge. The machine can used for sterilization, milling flour, softening, and extraction among others. In this study, we experimentally examined the conditions for food softening using pork as the food material in experiments. Softness was revealed to be related to the distance of shock wave generation point from meat and the number of shockwave processing.

Abstract: Recently, many countries are promoting the collection, the reproduction and the use of consumer goods；aluminum cans, PET bottles, and so on. On the other hand, the reproduction of the glass bottles is not so active excluding use as a returnable bottle, because the recycle cost is high. The glass bottles are fractured by the small fragment for reproduction. The small crushing fragments are called ‘Cullet’. The cullet is melted and molded again as glassware. The surface area is enlarged by making the bottle cullet, and it is possible to melt these efficiently. As a result, it becomes possible to shorten the time to melt the glass bottle and reduce a consumption of the fuel oil. The reasons with not active recycling of the glass bottle are that large-scale crushing equipment is required and it takes a lot of time and cost. This study proposed a new recycling technique for fracturing the glass bottle by using an underwater shockwave by explosive and electric pulse. The shock wave pressures produced by the explosive and the electric pulse energy were measured and the optimum crushing conditions were discussed.

Abstract: The basic behavior during underwater electrical discharge up to 10 kJ stored energy is investigated through both numerical analysis and optical-observation experiments. Since the authors have been investigating the use of underwater exploding phenomena for food processing and other applications, it is necessary to know the whole process which may affect the quality of the samples recovered. In the present investigation, the propagation of underwater shock wave was measured using a high-speed camera and compared with the numerically simulated results using LS-DYNA. Also, the motion of gas bubble, which is induced quite after the propagation of the shock wave, was measured and compared with the numerical simulation using the same code. The pressure of the bubble is not such high as the shock wave, but it is known that the impulse is not possible to be ignored due to its relatively long duration of the pressurization. Through a series of optical-observation experiments, it is confirmed that the numerical simulation is potentially possible to predict the whole phenomena for processing foods and other materials.

Abstract: By analyzing the characteristics of shock waves in underwater blasting of two bridge piers and monitoring their pressures, this paper found the rule that shock wave pressure varies with different distances from the explosion source. The method of comparison was applied in this study. Based on the characteristic parameters such as pressure amplitude and positive action time, the attenuation formula of shock wave in shallow water was proposed. The results of this paper are of great importance to the engineering design and construction as well as environmental safety assessment.

Abstract: In recent years, a method of food processing using underwater shock wave has been investigated. The underwater shock wave is generated by high voltage and large current gap discharge in water, and it is used for food processing in the present investigation. When the underwater shock wave is loaded on the food, the food cells are momentarily broken. Therefore, the food becomes soft, and possible to squeeze water easily. Also, seasonings can be penetrated inside of the food. The improvement of absorbing seasonings for the shock processed foods mainly on Japanese radish is reported in this paper.

Abstract: It is known to be able to expect the improvement of the harvest if the cropping time can be made early in a cold region such as Russia, Norway, Sweden and Hokkaido in Japan. Therefore, for the purpose of making cropping time early as much as possible, we researched the destruction of the frozen soil by the explosive. In the simple experiment, as compared with the experiment which placed the explosive directly on top of the frozen soil, it broke greatly in the experiment which poured out water 20 mm in height after placing an explosive directly on top of the frozen soil. Furthermore, it was found that the thawing time of residual frozen soil in the experiment using water is shorter than without water. In this research, in order to investigate the effect of the covered water in thawing frozen soil by explosive load, the numerical simulation was performed. The result of the numerical simulation was well in agreement with the experimental result, and it was clarified that destruction effect is increased by covering with water.

Abstract: Carbon fiber is employed to induce underwater shock wave by the high-voltage electric discharge. By the release of an energy 10 kJ stored in a high-capacity condenser bank, carbon fiber was exploded showing the evidence inducing underwater shock wave effectively to a thin plate to be formed.

Abstract: The underwater shock wave has been studied in the various fields. The application of this method can be used for a molding machining, a welding and an embossing in the metal processing [. Moreover, this processing method can be used for a pulverizing, a softening, and a sterilization in the food processing. The aim of this research is to make the rice powder using by the underwater shock wave without generating of heat [. Although the underwater shock wave is generated using an explosive, the handling of the explosive is extremely accompanied by danger. Therefore, we developed the electric discharging device made to generate the underwater shock wave. It is easier to carry on the experiment using this device than the experiment of an explosive. We developed a pressure vessel for generating the underwater shock wave in various fields. The developed pressure vessel has been improved by our research group. The pressure vessel made to generate the shock wave is manufactured from a new concept, and the coaxial cable is used for wiring of the device.

Abstract: We propose a new method for the efficient decompression of frozen food under high dynamic pressure. Two experiments are conducted on an ice block containing peeled shrimp: wire explosion and underwater shock wave. In these experiments, the ice is finely crushed, while the frozen peeled shrimps retain their original shape and can be efficiently extracted. Since ice crushing is performed momentarily, the defrosting time is significantly shorter than that in traditional thawing techniques, such as melting in running water or cold-water soaking. This new method could increase the efficiency of food production processes.

Abstract: Generally, emulsion fuel means mix of fuel and water. But normally, these two kinds of liquid easily separate. In this study, underwater shock wave is used to mix these liquid. Purpose of this study is to create emulsion fuel using underwater shock wave. That fuel is needed not to separate. In our experiment, samples were prepared which consists of diesel fuel, water, and other liquid which might help to make emulsification between water and diesel oil. These liquid are packed into polycarbonate bottles. And underwater shock wave is hit to these samples. Detonating fuse and electric detonator are used to make shock wave. The underwater shock wave is hit to each sample for 5 times. After this experiment, these samples are observed to see if these samples separate again or not. Results shows that emulsion fuel we made separated as time passed. In the future study, it is needed that establishment of the way to control those separation.