Life cycle of meats: an opportunity to abate the greenhouse gas emission from meat industry in Japan

The food industry is one of the world's largest industrial sectors, hence a large contributor of greenhouse gases (GHG) which cause global warming. This study evaluates the life cycle of various types of meat to determine if the GHG emission from the meat industry in Japan could be reduced if the population makes different dietary choices. It was confirmed that the GHG emission of beef was greater than that of pork or chicken. The GHG emission from meat in general also depends on the per capita caloric intake (if meat supplies the recommended animal protein or contributes to it at the present rate). In a healthy and balanced diet (9.2 MJ i.e., 2200 kcal in total, where either mixed meat or chicken or pork or beef contributes 2.2%), the GHG emission is estimated to be 0.28 or 0.17 or 0.15 or 0.77 kg CO? eq/person/day, respectively. A change in consumption patterns (from beef to chicken or pork) and the adoption of a healthy and balanced diet would help to abate about 2.5-54.0 million tons (CO? eq) produced by the meat industry each year in Japan.     

Self-ignition and explosion during discharge of high-pressure hydrogen

The phenomenon of self-ignition and explosion during discharge of high-pressure hydrogen was investigated. To clarify the ignition conditions of high-pressure hydrogen jets, rapid discharge of the high-pressure hydrogen was examined experimentally. A diaphragm was used to allow rapid discharge of the high-pressure hydrogen. The burst pressure was varied from 4 to 30 MPa. The downstream geometry of the diaphragm was a flange and extension pipes, with the pipe length varying from 3 to 300 mm. The diameter of the nozzle was 5 or 10 mm. When short pipes were used, the hydrogen jet did not ignite. However, the hydrogen jet showed an increasing tendency to ignite in the pipe as the length of the pipe became longer. At higher burst pressures, a diffusion jet flame was formed from the pipe. The blast wave from the fireball formed on self-ignition of the hydrogen jet resulted in an extremely rapid pressure rise.     

Investigation of the properties of the accidental release and explosion of liquefied dimethyl ether at a filling station

Dimethyl ether (DME) has been focused as a substitute for diesel fuel, and a number of studies have investigated engines fueled with DME because DME has a low auto-ignition temperature and does not generate particulate matter (PM). Therefore, in the last few years, the construction of DME filling stations for trucks in Japan has been planned. The introduction of DME vehicles requires expansion of DME supply stations, which in turn requires the collection of safety data and the establishment of safety regulations. The present paper describes an experimental investigation of the hypothetical scenario in which liquid DME is accidentally released and an explosion occurs. In the present study, large-scale leakage and ignition of DME were investigated and flame propagation data was obtained. We also measured the overpressure of the blast wave and the heat flux from the fireball. When the ignition position is near the nozzle, the flame propagation velocity is higher. The overpressure from the DME fireball is stronger than that from DME/air mixture deflagration. In summary, these results provide safety data for safety management of DME filling stations.