Giant multiple caloric effects in charge transition ferrimagnet

Kosugi, Yoshihisa*; Goto, Matato*; Tan, Z.*; Kan, Daisuke*; Isobe, Masahiko*; Yoshii, Kenji; Mizumaki, Masaichiro*; Fujita, Asaya*; Takagi, Hidenori*; Shimakawa, Yuichi*

Scientific Reports (Internet), 11(1), p.12682_1 - 12682_8, 2021/06

https://doi.org/10.1038/s41598-021-91888-8

Caloric effects of solids provide more efficient and environment-friendly innovative refrigeration systems compared to the widely-used conventional vapor compressive cooling systems. Exploring novel caloric materials is challenging but critically important in developing future technologies. Here we discovered that the quadruple perovskite structure ferrimagnet BiCuCrO shows a large multicaloric effect at the first-order charge transition occurred around 190 K. Large latent heat and the corresponding isothermal entropy changes 28.2 J K kg can be fully utilized by applying both magnetic fields (magnetocaloric effect) and pressure (barocaloric effect). Adiabatic temperature changes reach 3.9 K for the 50 kOe magnetic field and 4.8 K for the 4.9 kbar pressure, and thus highly efficient thermal controls are achieved by multiple ways.

Effective 3D data visualization in deep shaft construction

Inagaki, Daisuke*; Tsusaka, Kimikazu*; Aoyagi, Kazuhei; Nago, Makito*; Ijiri, Yuji*; Shigehiro, Michiko*

Proceedings of ITA-AITES World Tunnel Congress 2015 (WTC 2015)/41st General Assembly, 10 Pages, 2015/05

Rock spalling and countermeasures in shaft sinking at the Horonobe Underground Research Laboratory

Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Aoki, Tomoyuki*; Shigehiro, Michiko*

Proceedings of 6th International Symposium on In-situ Rock Stress (RS 2013) (CD-ROM), p.339 - 346, 2013/08

The Horonobe Underground Research Laboratory is planned to consist of the Ventilation Shaft (4.5 m in diameter), the East and West Access Shafts (6.5 m in diameter). The host rock of the URL site comprises Neogene sedimentary rocks. The unconfined compressive strength of the rocks is less than 20 MPa on average. Anisotropic stress distribution around the URL is also confirmed. Because several highly permeable fractures (hydraulic transmissivity: approximately 10m/s) with the size greater than the shaft diameter develop under the condition of around 2 in competence factor (i.e., the ratio of the unconfined compressive strength of rock to the initial stress) below a depth of 250 m, shaft sinking is a challenging issue from the viewpoint of tunnel engineering in the Horonobe URL Project. In this paper, the construction of the Ventilation Shaft below a depth of 250 m at the Horonobe URL is reported. During shaft sinking, fracture mapping of the shaft wall was performed. The geometry of the shaft wall was also measured using a three-dimensional laser scanner in order to investigate the shape and volume of rock spalling in the shaft wall resulting from the excavation work. Rock spalling was predominantly observed on the south and north wall rock corresponding to the direction of the minimum horizontal initial stress. A large amount of rock spalling also developed along a large-scale fault. With respect to the lining span and the layout of rockbolts, several support patterns were designed and installed as the countermeasures to prevent the development of excessive rock spalling. A flowchart for selecting the optimum support design was then developed.

Influence of rock spalling on concrete lining in shaft sinking at the Horonobe Underground Research Laboratory

Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Koike, Masashi*; Matsubara, Makoto*; Sugawara, Kentaro*

Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.911 - 916, 2013/01

A repository for high-level radioactive waste in deep underground consists of several underground structures such as access and disposal drifts and shafts. In deep geological disposal project, a shaft is the first underground structure to be constructed and the last one to be backfilled. Therefore, the stability of shaft is one of key factors to steadily manage the project in the construction and operation phases. In this paper, the authors discuss influence of rock spalling on concrete lining in shaft sinking. Japan Atomic Energy Agency has been constructing three shafts (one is for ventilation and the others are for access use) up to a depth of 500 m in the Horonobe Underground Research Laboratory. During the construction of the Ventilation Shaft (4.5 m in diameter) below a depth of 250 m, rock spalling occurred at several depths and an open crack has developed in a concrete lining installed just above rock spalling. The authors have measured geometry of shaft wall by using three-dimensional laser scanner. They also conducted numerical analysis in order to calculate change in stress distribution and deformation induced by rock spalling in a concrete lining and the surrounding rock. As a result, it was clarified that rock spalling induced tensile stress in the vertical direction in a concrete lining. Especially, the tensile stress in a concrete lining was likely to exceed tensile strength of a concrete lining in the case that it developed more than 100 cm in depth.

Spalling in response to shaft sinking at great depth in soft sedimentary rock

Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Matsubara, Makoto*

Chika Kukan Shimpojiumu, Rombunshu, 17, p.155 - 162, 2012/01

Japan Atomic Energy Agency has been constructing an underground research laboratory in order to enhance the reliability of relevant disposal technologies of high-level radioactive waste in Horonobe, Hokkaido. A ventilation shaft (4.5 m in diameter) and two access shafts (6.5 m in diameter) are being excavated through the Neogene sedimentary rocks until the depth of 500 m. Based on the results of borehole investigation and pre-grounting operation in bedrock with high permeability from 250 m to 375 m in depth, the three dimensional fracture distribution map were built and the locations with high possibility of spalling in shaft wall in response to excavation were predicted prior to the shaft sinking from a depth of 250 m. Some amounts of spalling has occurred in several depths during shaft sinking from 250 m to 280 m in depth. The shape of each spalling was measured by means of three dimensional laser scaning system. As a result, spalling in shaft wall occurred along the faults predicted based on the three dimensional fracture distribution. In addition, spalling by brittle failure in shaft wall was also observed with a few extensile fractures which were expected to be induced by excavation. Based on the shape of spalling, it was confirmed that the applied shaft sinking procedure properly prevented a massive spalling.

Development of the technology basis for holistic waste management taking into consideration whole fuel cycle system, 3; Electronic-performance analysis report to support nuclide migration analysis and report writing

Koo, Shigeru; Makino, Hitoshi; Umeki, Hiroyuki; Hioki, Kazumasa; Kawasaki, Daisuke*; Tachibana, Shoko*

no journal, , 

no abstracts in English

Development of construction technologies for underground facility; Attempt at the Horonobe Underground Research Laboratory Project

Inagaki, Daisuke; Tsusaka, Kimikazu; Miura, Yoichi*; Nago, Makito*; Shindo, Akihisa*; Ijiri, Yuji*; Koike, Masashi*; Hatakenaka, Chino*

no journal, , 

no abstracts in English

A Study of shaft sinking against fault at great depth in soft sedimentary rock

Inagaki, Daisuke; Tsusaka, Kimikazu; Aoyagi, Kazuhei; Hagihara, Takeshi*; Nago, Makito*; Minamide, Masashi*; Ijiri, Yuji*

no journal, , 

no abstracts in English