Hironori Maehara

Mechanism of the Shock Wave Generation and Energy Efficiency by Underwater Discharge

We are developing the rice powder manufacturing system using an underwater shock wave. The purpose of this study is to research a mechanism of the shock wave generation and energy efficiency by underwater discharge in order to increase energy of the underwater shock wave. We observed the shock wave generation using the visualization device with a high speed camera, and measured voltage current characteristics at the same time. As a result, it was clarified that countless underwater shock waves were generated at the time of water plasma expansion by discharge. But, the shock wave was not confirmed at the time of after a second peak of the damping oscillation. It was clarified that one part of charging energy was used to generation of the shock wave. Therefore, it was clarified that to release energy by the critical oscillation is desirable for efficient generation of the shock wave.

Development of wood and wood ash-based hydroxyapatite composites and their fire-retarding properties

For making efficient use of waste wood ash emitted from wood biomass plant, the wood and wood ash-based hydroxyapatite (HAp) composite was produced and their flammability characterization was studied by thermogravimetric (DTA-TG) analysis, oxygen index (OI) measurement and cone calorimeter test. The results show that the exothermic and weight loss peaks in DTA-TG combustion profiles due to their significant thermal decomposition were weakened by the HAp agent impregnation. In addition, the OI value of HAp composites was increased by the HAp combining and the OI showed a correlation with the HAp contents. Also, the cone calorimeter study revealed that the heat release rates were decreased with increasing amount of HAp injection and accordingly their total heat release has an inverse relationship to the HAp contents. These results indicate that the treatment with wood ash-based HAp agents can enhance the flame retardancy of the treated woods.

Development of the rice-powder manufacturing system using underwater shock wave

Self-sufficiency in food is very low (about 40%) in Japan. Therefore, the rice powder is paid to attention because it can be processed to the udon (noodle) and bread etc. We has already developed the rice-powder disintegrator using the underwater shock wave by the electrode. But it has not been cleared what is the most suitable pressure vessel. The purpose of this study is to investigate the most suitable configuration of the pressure vessels for manufacturing the rice-powder using the underwater shock wave. Experimental conditions to manufacture the rice-powder (particle size is 100 μm) is clarified using this device. Moreover, the manufacturing efficiency of the rice-powder, the relation between the number of the shock wave generation and the grain degree of rice-powder is clarified.

A New Processing of Ginger Using the Underwater Shock Wave

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.

Development of the Pressure Vessel for Manufacturing the Rice-Powder Using the Underwater Shock Wave

We have been researching the food processing technology by using the underwater shock wave. The rice-powder used for various foods has been demanded in Japan now. The purpose of this study is designing and development of the pressure vessels for the manufacturing rice-powder device using the underwater shock wave. The pressure vessel was made into the oval shape which focuses the energies generated under the underwater shock wave. The speed and pressure of the shock wave which were generated underwater are confirmed with a high speed camera. The durability and performance of this device is confirmed by manufacturing the rice-powder.Copyright

Food Processing Trials Using Underwater Shock Wave by Electrical Discharge

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.

The numerical analysis of food processing using shock wave

In recent years, the use of the shock wave has increased not only in thefields of the material development and the metal processing, but also in thefield of the medical treatment, of the environment as the science andtechnology upgrades. We have focused on the food processing by usingan underwater shock wave. This process has various advantages such asshort processing time and a very few energy consuming and no nutrientreduction due to non-thermal processing. An efficient food processingequipment is needed to evaluate the phenomenon of the shock waveloading, the numerical method for food processing by underwater shockwave is quite skillful and very important. Especially in the design for thesuitable pressure vessels for food processing, the phenomenon inpressure vessel are very complex and in multi-physics manners. Therefore,in numerical calculation, a lot of parameter for the numerical analysis isneed for pressure vessel material and various foods. In this study, thepurpose is to clarify unknown parameters of the potatoes by measuringUs-up.

Study on development of vessel for shock pressure treatment for food

In recent years, the food processing using high-energy pressure pulse is gaining attention due to no heat evolution in the process. In this study a vessel was designed for the shock pressure treatment of food. An underwater shock wave generated by the detonating fuse was applied as the source of high-energy pressure pulse. The underwater shock wave was investigated by optical observation and pressure measurement experiments. The results are then compared with the computer simulation using LS-DYNA code. The agreement between the experimental results and the numerical analysis is found to be good. The food processing of apple was performed using the designed vessel. The hardness of the apple has decreased showing the effectiveness of the newly designed vessel.

Flashing Phenomena of Liquid Nitrogen in a Pressure Vessel Under Rapid Depressurizations

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. The purpose of this study is to clarify some fundamental features of the flashing of cryogenic fluids. Experiments on flashing of liquid nitrogen were conducted to clarify the effect of surface roughness of a vessel. Two types of pressure vessel were used. One is a vessel made of stainless steel, the other is a vessel made of glass. In the case of glass vessel, many types of boiling have been observed. The degree of superheat at the start of boiling was found to depend strongly on the rate of depressurization.Copyright

Study of the Suitable Pressure Vessel for the Rice-Powder Manufacturing Using the Underwater Shock Wave

Self-sufficiency in food is very low (about 40%) in Japan. Therefore, the rice powder is paid to attention, because it can be processed to the udon (noodle) and bread etc. We have already developed the rice-powder disintegrator using the underwater shock wave by the electrode. But it has not been cleared what is the most suitable pressure vessel. The purpose of this study is to investigate the most suitable configuration of the pressure vessels for manufacturing the rice-powder using the underwater shock wave.Experimental conditions to manufacture the rice-powder (particle size is 100μm) is clarified using this device.Moreover, the manufacturing efficiency of the rice-powder, the relation between the number of the shock wave generation and the grain degree of rice-powder is clarified.Copyright