The elastic properties of a circular notched bar under bending load are treated by the theory of thin plates, by the theory based on the rigorous solution of a hyperbolic notch and by the structural analysis of the finite element method respectively. The experimental results on the bending elastic coefficients verify these theoretical treatments not only in the thickness dependences onthe geometrical parameters, but also in the absolute values with a difference ofless than 20%. As far as the theoretical treatments are concerned, the geometrical average of the thickness of the notched bar and the radius of the circle are universally found to be the significant parameters in estimating the elastic properties. And also in the numerical analysis procedure, a systematic method to generate the elements in the circular notched bar is proposed, which will be a useful tool in further numerical analysis with the highest precision.
Surface deterioration and tracking breakdown in an atmosphere of low-pressure have been studied recently for a large number of organic insulating materials. In this paper, a possible process for surface deterioration and tracking breakdown of organic insulating materials due to glow discharge in an atmosphere of low-pressure is investigated with special attention to the decrease in volume with the time exposed to glow discharge. Polyethylene (PE), polyvinyl-chloride (PVC), polystyrene (PS), polymethylmethacrylate (PMMA) and epoxy resin (EX) were used for the samples in this test. Tracking and arc resistance test according to IEC 112 and ASTM D-495 methods were performed on the five samples used in this test so that the process for the deterioration and breakdown mechanism of organic insulating materials could be discussed.
Positron annihilation technique is very sensitive to lattice defectsin metals and alloys. In the present article, many applications which have been made in the last decade are reviewed. Special emphases are placed on the advantage of this technique in thermal equilibrium measurements and recovery studies ofdefects.
The redefinition of the candela, one of the base units of the SI, was adopted at the 16 th Session of the General Conference on Weights and Measuresin Oct. 1979. The new definition is based on the absolute radiometry and the internationally agreed value of the maximum spectral luminous efficacy of radiation. In this review are outlined the necessity and the proposal of the redefinition, procedures taken for the determination of the maximum luminous efficacy, and arguments which were made in the Consultative Committee on Photometry and Radiometry andd the Consultative Committee for Units, on the replacement of the candelaby the lumen and also on the treatment of the SI units including biological efficiency factors.
Physical problems in designing a tokamak fusion reactor are reviewed. INTOR-like device is considered as a reference reactor. The problems include 1) poloidal field coil configuration, 2) poloidal divertor, 3) toroidal field ripple and burn control and 4) plasma disruption. Emphases are placed on the issuesclosely related to the reactor design and R & D items to be investigated in future. It should be useful to clarify these physical problems at present, since it will greatly help to further pursue more optimized core plasma and to set the concrete goals for the development of technology in future commercial reactors.
Hybrid magnets are combined systems of highpower watercooled magnetsand superconducting magnets, having certain advantages in the production of steady high magnetic fields higher than 20 T. These fields are required for researches on high-field superconductors which may possibly be used for nuclear fusion reactors. In this paper the technology of the steady-state high-field magnet and the present status of world-wide high-field facilities are reviewed, followed bya brief description of our hybrid magnet project.
Recent experimental and theoretical investigations on the order-disorder phase transition and dynamic mechanical properties as well as the other physical properties of the monodisperse polystyrene latexes are reviewed with special emphasis on the fact that a latex in the ordered state is a real crystal in spite of its apparent fluidity.