“Fuzzy” has come up to be a boom in Japan. Many industrial applications using fuzzy theory have been practiced in various fields, such as electric home appliances, chemical or biochemical process controls, image understanding, various kinds of diagnosis etc. In this paper, the fundamentals of fuzzy theory are surveyed and some applications are introduced, followed by some diccussions on perspectives of fuzzy system engineering.
Tritium research activities at universities in Japan are reviewed. The typical experiments of in-situ tritium recovery from fission or fusion neutron-irradiated lithium compounds show that the tritium release are enhanced by 1 per cent H2 gas addition to the He sweep gas. Permeation, solubility, and diffusion coefficient of tritium in various organic and metallic materials are surveyed and are listed in Table 1 for inorganic materials. The fundamental works have been made extensively on the enrichment of used fusion fuel and propose the optimized operating conditions for hot wire column with a cold or a cryogenic wall. An effective removal of tritium from contaminated ceramic multiplier by the photon irradiation are elaborated more fully in the reference cited.
In this report, tensile strength characteristics of tough pitch copper were investigated. As-rolled and annealed specimens were provided. So, tensile directions are 0° and 90° to rolling direction. The following results are obtained in relation between X-ray diffraction parameters and values of tensile plastic deformation. (1) A monotonous increase of half value breadth in X-Ray parameters is effective to detect the tensile plastic deformation quantity in as-rolled tough pitch copper. (2) A monotonous increase of integrated breadth in X-Ray parameters is effective to detect the tensile plastic deformation quantity in annealed tough pitch copper, because kα1 and kα2 lines were separated. (3) Also hardness changes during tensile deformation are coincide with the increasing of X-Ray parameters.
The actuator of Shape Memory Alloy coil with bias spring was developed and its precision was investigated. This device was operated by electrical heating on the Pulse Width Modulation method using computer in oder to make high precision of position control. The position was measured by electric micrometer. This was made under the conceptof the stage which was used in semiconductor production lines and so on for the reason of the cleanness of this actuator.
The effects of microstructure factors and manufacturing process on the precipitation of hydrides in Zircaloy-4 plate have been studied. A quantitative technique described in Ref. 1 has been used to evaluate the susceptibility to radial hydride formation under the influence of texture, residual stress and externally applied tensile stress. Image treatment was carried out to determine the average orientation of hydrides. The hydride oriented threshold stresses were estimated, following an improved approach which had been firstly developed by Sauthoff and then applied to Zr-H system by Puls.2 Both analytical and experimental results indicate that the threshold stress is influenced by the microstructure and thermomechanical treatment of Zircaloy-4, and by the hydrogen concentration in a very complex manner. After examining the hydride morphologies of formerly cold-rolled sheets of two different fabrication routes in stress-relieved, recrystallized and β treated states, it may be concluded that the distribution morphology of hydrides can be selected, and their noxiousness and effective contribution to the embrittlement can be thus minimized by controlling texture, grain structure, and manufacturing process.
A new solid phase coextrusion process to manufacture metal matrix composites has been developed. As part of this study, the influence of following parameters on the behavior and damage mechanisms of the composite was investigated: aspect ratio of the fibers, orientation of reinforcement and local concentration distribution. This has been achieved through an equivalent inclusion analytical approach based on a micro-macro modelization. The prediction of the elastic constants, the coefficients of thermal expansion and the yield criterion can be determined from the microstructure. Finite element calculations complete this model by computing a three phase basic cell. The influence of the distribution of fibers on the development of local plasticity has been demonstrated. It appears that the configuration of fibers side by side has a dramatic effect on the propagation of damage which occurs at the fiber tip. An analytical criterion for damage initiation has also been suggested. These results are compared with in situ tensile tests performed inside a scanning electron microscope, where every stages of the failure mechanism can be observed.
The determination of macroscopic and microscopic residual stresses, their influences and their variations have to be taken into account to study the behaviour of short fiber reinforced metal matrix composite behaviour under external applied stresses. X-ray and neutron diffraction applied to matrix and reinforcement made it possible to give a good evaluation of these stresses. A great care is needed for the evaluation of the stress free parameter a0 especially in the case of stress and chemical composition gradients. First order thermal stresses similar in two Al-SiC and Al specimens but in the previous one, second order stresses are very high.
Milling processes of powder mixtures of elemental Nb and Al and those of Ti and Al which resulted in the formation of amorphous and crystalline intermetallic compounds were investigated from the viewpoint of change in morphology and microstructure of milled powder particles during milling. The morphological and microstructural change was observed by optical and scanning electron microscopy. The formation of alloy phase from the elements was examined by microhardness measurements made on the milled powder particles. The amorphization behavior was monitored by X-ray diffraction and thermal analyses. As a result, the milling processes of both Nb/Al and Ti/Al were found to go through the follow steps; in the initial stage of milling flaky and plate-like particles with a characteristic structure consisting of an Al-matrix with small Nb or Ti fragments embedded in it were formed; subsequently, lamellar structure developed in these particles due to their plastic deformation; large globular particles were formed by coalescence of the lamellar particles; refinement of the lamellar structure and the eventual formation of an amorphous or crystalline alloy phase occurred in surface regions of the globular particles; in the final stage fine amorphous or crystalline powder broke off from the surfaces of the globular particles. A glass forming range of Nb/Al determined by X-ray diffraction analysis in the present experiment was 60-90wt.%Nb. The amorphization of Ti/Al powder was found to be strongly dependent on the milling ball size. TEM study on the amorphous Ti/Al powder particles revealed that the amorphous particles includes crystallites of nanometer size in an amorphous matrix.
Magnesia-partially stabilised zirconia (Mg-PSZ) is one of the toughest-known ceramic materials. Over the last decade there has been an evaluation of these materials for biomedical applications including hip endo-prosthesis. These studies have examined the bio-compatibility, strength, fatigue and environmental stability. More recently these observations have been complemented with wear evaluation tests using an anatomical designed hip wear simulator and extensive clinical observations. This paper will review the data available.
X-ray fractography is a technique to analyze the cause of the fracture from the X-ray information obtained from the irradiation on the fractured surface. The qualitative relations between the X-ray parameters and the fracture mechanics parameters has been known but quantitative relation is still under development. Through various kinds of load controlling fatigue tests, including constant effective stress intensity factor range tests, a new model for the residual stress distribution was proposed. The quntitative relation between the X-ray and fracture mechanics parameters can be obtaind from this model.
The development of ceramic coating to metals was stimulated by the need for high temperature, wear and corrosion resistant materials. Recently TiN, TiC, TiB2, and Al2O3 are used as ceramic coating materials. In the present study, the X-ray method was successfully applied to measure the residual stress distribution in TiN, TiC, TiB2, and Al2O3 coated steels. The X-ray elastic constants were determined and compared with the mechanically measured values. In all ceramic coated films, the X-ray elastic constants were larger than the mechanical ones. Residual stress distributions of. TiN and TiC coated films were determined by the X-ray method. It indicated high compressive stress above -2.5(GPa) to -3.5(GPa) in the TiN and TiC coated films.