Showing papers by "Yoshio Arai published in 1988"

Head rest adjusting device

Abstract: A head rest adjusting device using a friction mechanism, which permits the forward and backward rotative adjustment of the head rest relative to a head rest stay. The friction mechanism comprises a substantially U-shaped leaf spring receiving the head rest stay therein, and a protruding resilient section is formed on the folded area of the leaf spring so as to give an additional resiliency to the leaf spring per se and thus provide a stable proper friction against the rotation of the head rest about the stay.

Fast track-finding processor based on RAM look-up table for the VENUS detector at KEK

Abstract: We have developed a fast track-finding processor using signals from the central tracking chamber of the VENUS detector in the TRISTAN experiments. Particle tracks are recognized by a look-up table made with a high-speed static RAM. This method enables us to implement the track finder in the first level triggering. The track finder has been working excellently under heavy background due to synchrotron radiation. A processing time of 110 ns is attained.

Data acquisition system for the VENUS detector at TRISTAN

Abstract: A data acquisition system for the VENUS detector at the TRISTAN electron-positron collider is presented. The whole system of the VENUS detector consists of nine different kinds of principal detectors, and the total number of electronics channels of the system reaches about 30 000. A FASTBUS system was introduced as the main data path and the TKO and the CAMAC standard have also been utilized for the frontend electronics. A FASTBUS interface to an on-line computer (VAX11/780), simplex segment interconnect and many data acquisition modules were developed. Most of the data are analyzed in a VAX cluster system in real time. Data logging is done in a main frame computer (FACOM M382) by using an automatic loading cartridge tape subsystem.

The FASTBUS master module based on a 68020 microprocessor

Abstract: A FASTBUS master module, 68K20FPI (68020 FASTBUS Processor Interface), which has the Motorola MC68020 32-bit microprocessor unit (MPU) and the MC68881 floating point coprocessor (FPCP), is presented The 68K20FPI is intended to be used for a second-level trigger processor in a multiprocessor environment It has a local-memory sunboard of 1-Mb static RAMs and a 512-kb ROM port, which are accessed from both the CPU and FASTBUS side The SCSI (Small Computer Systems Interface) is adopted as a disk interface and also as a high-speed ( approximately 4-Mb/s) interface to other computers The Ethernet interface is used for a communication line between the 68K20FPIs and a host computer Two RS232C interfaces are used as terminal and host communication ports A NIM level input and output are used for trigger purposes >

Evaluation of fracture mechanics characteristics of a high strength graphite IG-11.

Abstract: Fracture toughness and crack growth characteristics of stress corrosion cracking and fatigue were investigated for an isotropic fine grain size graphite, IG-11, one of the candidates for the core components of High Temperature Gas Cooled Reactors. The results obtained are summarized as follows:(1) The fracture toughness and the fracture resistance were reasonably described by using the stress intensity factor. Introduction of the J-integral as a parameter did not bring an increase in accuracy.(2) The plain strain fracture toughness KIc values for the fatigue precracked specimens were 0.93-1.00MPa√m. Without fatigue precracking, 10-20% decrease in fracture toughness was observed. In both cases, further crack growth brought an increase in the fracture resistance KR up to 1.05-1.25MPa√m.(3) The stress corrosion cracking did not occur in the material tested. On the other hand, the fatigue crack growth below KIc was observed although the crack growth mechanism is quite different from that for conventional metallic materials.

Evaluation of fracture mechanics characteristics of an alumina particulate filled epoxide composite.

Abstract: The plane strain fracture toughness, KIc, the fracture resistance, KR, and the crack growth characteristics of stress corrosion c racking and fatigue were investigated for an alumina particulate filled epoxide composite. Based on the results, basic fracture characteristics were evaluated. The results obtained are summarized as follows: (1) The resistance to the stable crack growth as well as the fracture initiation is described as K=KIc. (2) Below KIc, stress corrosion cracking occurs. The threshold stress intensity, KIscc, is 0.89 KIc. (3) The threshold stress intensity for fatigue crack growth is smaller than KIscc. A marked influence of the stress ratio on the fatigue crack growth rates is observed. On the other hand, there is no effect of cyclic frequency. It is judged that interaction with stress corrosion cracking is not so significant.