Estimation of planes of a rock mass in a gallery wall from point cloud data based on MD PSO

Matsuura, Yuto*; Hayano, Akira; Itakura, Kenichi*; Suzuki, Yukinori*

Applied Soft Computing, 84, p.105737_1 - 105737_9, 2019/11

https://doi.org/10.1016/j.asoc.2019.105737

LiDAR (laser imaging detection and ranging) has been developed to obtain a high-resolution point cloud data indicating the detailed 3D shapes of an object. To identify discontinuities in a rock mass of a tunnel gallery wall, it is necessary to approximate the rock mass surface with small planes. Normal vectors of the planes are important to identify discontinuities. We developed an algorithm for estimation of planes based on multi-dimensional particle swarm optimization (MD PSO) from point cloud data. Point cloud data were segmented into bounding boxes and grouped into clusters by MD PSO. Planes were estimated using the least squares method for point cloud data in the respective clusters. The newly developed MD PSO algorithm was evaluated using point cloud data obtained from a gallery wall. Evaluation was carried out in comparison with the previous developed variable-box segmentation (VBS) algorithm. The MD PSO-based algorithm showed a 7% higher accuracy than that of the VBS algorithm.

Evaluation growing and collapsing behaviors of cavitation bubbles under flowing condition

Kawamura, Shunsuke; Naoe, Takashi; Ikeda, Tsubasa*; Tanaka, Nobuatsu*; Futakawa, Masatoshi

Advanced Experimental Mechanics, 4, p.33 - 37, 2019/08

A mercury enclosure vessel made of stainless steel is used as a spallation target in the pulsed spallation neutron source at J-PARC. It is severely damaged by the cavitation induced with pressure waves in association with the pulsed proton beam injection. A double-walled structure with a narrow mercury channel was adopted in the front end of the target vessel to reduce the cavitation damage. It has been experimentally demonstrated that the cavitation damage could be mitigated in the narrow channel but its mechanism has been unclarified yet. In this study, we investigated the cavitation from growing to collapsing through visualizing the spark-induced cavitation bubbles under flow field using a high-speed video camera. Furthermore, we measured the wall vibration due to the cavitation bubble collapse with changing flow velocity parametrically. It was found that the microjet collided perpendicular to the wall in the stagnant flow condition while it collided with an inclined angle from the perpendicular direction, suggesting that the collision pressure on the wall was reduced by flowing.

Dynamic properties of human -synuclein related to propensity to amyloid fibril formation

Fujiwara, Satoru*; Kono, Fumiaki*; Matsuo, Tatsuhito*; Sugimoto, Yasunobu*; Matsumoto, Tomoharu*; Narita, Tetsuhiro*; Shibata, Kaoru

Journal of Molecular Biology, 431(17), p.3229 - 3245, 2019/08

https://doi.org/10.1016/j.jmb.2019.05.047

-synuclein (Syn) is an intrinsically disordered protein (IDP) with unknown function. Syn is known to form amyloid fibrils, which are implicated with the pathogenesis of Parkinson's disease and other synucleinopathies. Elucidating the mechanism of fibril formation of Syn is therefore important for understanding the mechanism of the pathogenesis of these diseases. Here, using the quasielastic neutron scattering (QENS) and small-angle X-ray scattering (SAXS) techniques, we investigated the dynamic and structural properties of Syn. These results imply that fibril formation of Syn requires not only the enhanced local motions but also the segmental motions such that the proper inter-molecular interactions are possible.

Horonobe Underground Research Laboratory Project; Investigation program for the 2019 fiscal year

Aoyagi, Kazuhei

JAEA-Review 2019-008, 20 Pages, 2019/07

JAEA-Review-2019-008.pdf:3.33MB

As part of the research and development program on the geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. According to the research plan described in the 3rd Mid- and Long- term Plan of JAEA, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues of the Horonobe URL Project, and schedule of future research and backfill plans of the project will be decided by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. The investigations will be conducted in three phases, namely "Phase 1: Surface-based investigations", "Phase 2: Construction phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase" (research in the underground facilities). This report summarizes the investigation program for the 2019 fiscal year (2019/2020). In the 2019 fiscal year, investigations in "geoscientific research", including "development of techniques for investigating the geological environment", "development of engineering techniques for use in the deep underground environment" and "studies on the long-term stability of the geological environment", are continuously carried out. Investigations in "research and development on geological disposal technology", including "improving the reliability of disposal technologies" and "enhancement of safety assessment methodologies", are also continuously carried out.

Assessment report on research and development activities in FY 2018; Activity "Research and development on J-PARC" (Interim report)

J-PARC Center

JAEA-Evaluation 2019-003, 52 Pages, 2019/06

JAEA-Evaluation-2019-003.pdf:6.61MB

Evaluation Committee of Research Activities for J-PARC for interim assessment of Japan Proton Accelerator Research Complex evaluated the management and research activities of J-PARC center on the explanatory documents and oral presentations during the period from April 2015 to December 2018. This report summarizes the results of the assessment by the Committee with the Committee report attached.

Cryogenic sample environments shared at the MLF, J-PARC

Kawamura, Seiko; Takahashi, Ryuta*; Ishikado, Motoyuki*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ouchi, Keiichi*; Kira, Hiroshi*; Kambara, Wataru*; Aoyama, Kazuhiro*; Sakaguchi, Yoshifumi*; et al.

Journal of Neutron Research, 21(1-2), p.17 - 22, 2019/05

https://doi.org/10.3233/JNR-190106

The Cryogenics and Magnets group in the Sample Environment team is responsible for operation of cryostats and magnets for user's experiments at the MLF in J-PARC. We have introduced a top-loading He cryostat, a bottom-loading He cryostat, a dilution refrigerator insert and a superconducting magnet. The frequency of use of them dramatically becomes higher in these two years, as the beam power and the number of proposal increase. To respond such situation, we have made efforts to enhance performance of these equipment as follows. The He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of He. Recently we made an additional program for automatic temperature control with only the sorb heater. Last year, a new outer vacuum chamber of the magnet with an oscillating radial collimator (ORC) was fabricated. The data quality was drastically improved by introducing this ORC so that the magnet can be used even for the inelastic neutron scattering experiments.

Verification of a probabilistic fracture mechanics code PASCAL4 for reactor pressure vessels

Lu, K.; Katsuyama, Jinya; Li, Y.; Miyamoto, Yuhei*; Hirota, Takatoshi*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 9 Pages, 2019/05

Separation of radiocaesium-bearing micro particle from environmental samples; Application to litter samples

Tagomori, Hisaya; Dohi, Terumi; Ishii, Yasuo; Kanaizuka, Seiichi*; Fujiwara, Kenso; Iijima, Kazuki

JAEA-Technology 2019-001, 37 Pages, 2019/03

JAEA-Technology-2019-001.pdf:26.85MB

An efficient methodology for separating the radiocaesium-bearing micro particles (CsMPs) released by the TEPCO's Fukushima Dai-ichi Nuclear Power Station accident is required to investigate their spatial distribution and physicochemical properties. In this report we developed an efficiency separation method for CsMP from litters since the radiocaesium in litter may affect the radiocaesium cycling in forest ecosystem. One CsMP separation from litter containing lots of soil particles was attained within three days using electron microscopic analysis with digestion treatment of organic matter. This methodology is expected as CsMPs efficient separation method for not only forest floor litter but also barks and leaves of living tree, and other organic materials in the forested environment.

Electronic structure in heavy fermion compound UPdAl through directional Compton profile measurement

Koizumi, Akihisa*; Kubo, Yasunori*; Yamamoto, Etsuji; Haga, Yoshinori; Sakurai, Yoshiharu*

Journal of the Physical Society of Japan, 88(3), p.034714_1 - 034714_6, 2019/03

https://doi.org/10.7566/JPSJ.88.034714

Summaries of research and development activities by using supercomputer system of JAEA in FY2017; April 1, 2017 - March 31, 2018

Information Technology Systems' Management and Operating Office

JAEA-Review 2018-018, 167 Pages, 2019/02

JAEA-Review-2018-018.pdf:34.23MB

Japan Atomic Energy Agency (JAEA) conducts research and development (R&D) in various fields related to nuclear power and utilizes computational science and technology in many activities. As shown in the fact that about 20 percent of papers published by JAEA are concerned with R&D using computational science, the supercomputer system of JAEA has become an important infrastructure to support computational science and technology. In FY2017, the system was used for R&D aiming to restore Fukushima (environmental recovery and nuclear installation decommissioning) as a priority issue, and for JAEA's major projects such as R&D of fast reactor cycle technology, research for safety improvement in the field of nuclear energy, and basic nuclear science and engineering research. This report presents a great number of R&D results accomplished by using the system in FY2017, as well as user support, operational records and overviews of the system, and so on.