H-IIB launch vehicle is the newest and the most advanced Japanese rocket which can transport 16.5 ton of cargo vehicle (HTV) to International Space Station (ISS) and up to 8 ton of payload into geostationary transfer orbit. H-IIB has been developed efficiently under the government-industry joint framework of JAXA and MHI. Its first launch mission to transfer the first HTV to ISS was successfully completed in September 2009 as scheduled. The efficient and quick development and success are based on the advanced technology accumulated in JAXA and Japanese companies through Japanese rocket development history.
High-power pulsed spallation neutron sources are being developed in the world. A mercury target is installed at MLF ( Materials and Life science experimental Facility ) in J-PARC (Japan Proton Accelerator Research Complex), which will promote innovative science. At the moment the proton beams bombard the mercury target, pressure waves will be generated in mercury by thermally shocked heat deposition. Cavitation will be induced through the pressure wave propagation in mercury and eroded the vessel inner surface contacting with mercury, i.e. pitting damage. The eroded vessel wall is damaged by cyclic fatigue because pulsed proton beams strike the target repeatedly. In the paper, the effects of pitting damage, cyclic fatigue damage and mercury environment on the lifetime of the mercury target, and mitigation techniques for pressure waves and cavitation damage are described.
In the past, a serious railroad accident had occurred in Japan. In that accident, it had taken a long time to rescue the confined passengers within the crushed trains, because of the danger of the ignition to combustible vapor of leaked gasoline. Through the repeated occurrence of such fire accidents, the Fire and Disaster Management Agency (FDMA) in Japan was strongly demanding the development of the rescue apparatus that could be used in the combustible vapor and deployed the water jet cutter system all over the rescue parties. Under these circumstances, the Water Jet Technology Society of Japan (WJTSJ) was received the consignment of the research supported by the science and technology promotion system for fire fighting and disaster prevention of FDMA in Japan. The WJTSJ has started up the fire fighting project team to research the water jet cutter system from various contents. On this project, seven research workings were organized and these researches and developments have achieved respectively. In this paper, the outlines of this project and short summery of these workings research and development are reported.
This paper introduces the basic theory of advanced weather radar which consists of polarimetric technique and dopplar measurement. Moreover, equations representing the cloud microphysical processes for both precipitation particls development and air mass movement are explained briefly.
Microbubble destruction and the induced cavitation bubble behavior are regarded as key phenomena affecting the enhancement of sonoporation. In the present study an experiment was carried out for investigating the interaction of ultrasound waves with microbubbles. Test liquid was a suspension of Sonazoid ultrasound contrast agent diluted with distilled water with the volumetric concentration of 10 % [v/v], which was set in a cylindrical vessel, i.e. one of a 24 well-plate, conventionally used in in vitro experiments and irradiated by ultrasound waves with the frequency of 1 MHz. It was found that microbubbles were rapidly destroyed and the survival number was reduced to half the original number within 100ms for all the liquid depths examined here. A maximum number of cavitation bubbles was achieved at a certain exposure time less than one second where more than sixty cavitation bubbles were generated, subsequently behaving in the observation volume (= 14 mm3). Although almost the microbubbles were crushed within one second, we occasionally observed a special situation where plenty of cavitation bubbles happened at the exposure time of five seconds due to the circulation flow generated by the acoustic radiation pressure coupled with the flow induced by the free surface fluctuation.
Direct numerical simulation (DNS) of the high-Fr turbulent open-channel flow at the Froude number of 1.8 based on the bulk velocity, gravity acceleration, water depth, were carried out by means of the multi-interfaces advection and reconstruction solver (MARS) method. In this high-Fr flow, surface waves are constructed of large-scale gently bumped waves with the maximum wave-height approximately corresponding to 4% of the water depth and the high wave-number isotropic waves produced by surface fluctuations. This high wave-number surface deformations might be increased the wall-normal turbulent intensity and the redistribution ratio of turbulent intensities near free-surface was in good agreements with the experimental formula proposed by Nezu (2002).
In the present study, cross-sectional images of the assumed particle distribution of a particle-liquid two-phase flow are simulated using a newly proposed algorithm and electrical resistance tomography (ERT) with four current patterns. The first step of the algorithm is a forward problem, which involves calculating the electrical potential on electrodes from the assumed particle distribution by solving the Maxwell equation. The second step of the algorithm is an inverse problem, which involves calculating the particle distribution from the electrical voltage calculated by the forward problem. In the simulation conditions of the four current patterns, namely, opposite, adjacent, one-reference, and trigonometric methods are used to discuss the most accurate current patterns in three types of particle-liquid two-phase flow, namely, annular, stratified, and dispersed flows. The simulation results reveal that the current pattern depends on the flow conditions. In particular, among the four current patterns, the trigonometric method is found to be preferable.