Papers by Author: Hironori Maehara

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: 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: This study attempts to clarify underwater shock waves using a food container designed for food processing. The underwater shock wave is driven by a spark or wire explosion from a high-capacity condenser bank. Since the applied pressure must be known to control the experimental conditions, a numerical simulation was conducted and the results were compared with measurements using an elastic bar placed in the water.

Abstract: The aim of study is to confirm a new technique that can crush the frozen soil and/or ice block using underwater shock wave generated by the underwater explosion of explosive. This technique can lead to the earlier sowing, which can have the larger harvest because the duration of sunshine increases. Especially, in Hokkaido prefecture, Japan, if the sowing is carried out in April, we can expect to have 150% of harvest in the ordinary season. This technique is effective against the cold regions, for example, Russia, Norway, and Sweden, etc. In order to check about that influence we tried to give an actual frozen soil a shock wave. We could get a result that existence of water layer serves an important role in promotion of thawing by the shock loading to the frozen soil. That role was confirmed from the result of numerical simulation.

Abstract: In recent years in Japan, the demand of cryogenic fluids like a LH2, LNG is increasing because of the advance of fuel cell device technology, hydrogen of engine, and stream of consciousness for environmental agreement. On the other hand, as for fisheries as well, the use of a source of energy that environment load is small has been being a pressing need. We paid attention to the effective use of cold heat of the liquid fuel which is a cryogenic fluid. That method is to use a cold heat which an cryogenic fluid has, without a heat exchanger. The mixture of the extreme low temperature fluid and the normal temperature fluid becomes the cause which causes pressure vessel and piping system crush due to explosive boiling and rapid freezing. Therefore, we carried out the experiments related to promotion of evaporating cryogenic fluids, in the contact directly of the room temperature fluids and cryogenic fluids.

Abstract: In this study, a new processing technique of ginger using underwater shock wave has been studied. The extraction efficiency of ginger using controlled and shock wave method has been compared. The shock wave shows good improvement in the extraction efficiency of ginger.

Abstract: The aim of this study is to confirm a new technique that can crush ice by underwater shock wave generated by underwater explosion of explosive. Damage caused by ice occurs in the cold regions at different circumstances. For example, the problems such as accretion of ice on the drainage of snow melting system, on the ship and on farm lands. The solution for such problems is to use a method of heating. As the necessary quantity of heat is enormous and the problem of global warming exists, the dynamic way of solving is desirable. At first, we carried out experiments using detonating cord and ice block. The process of propagation of shock wave in ice was observed by using the high-speed camera.

Abstract: In cases where a borehole has been dug in the ground and subjected to an explosive load, the soil around the borehole wall will be abruptly compressed and a cavity will then be created in the portion of the ground that is surrounded by the compressed soil wall. When this procedure is applied to the construction of tunnels or foundations, underground spaces can be created with minimum mucking and a thinner lining. The authors carried out some laboratory experiments in which small boreholes were expanded by blasting. The results of the experiments increase our knowledge and elevate the possibility of applying this procedure to underground space construction.