This paper presents an experimental investigation on forced convective boiling of a refrigerant HCFC123 in a mini-tube. The inner diameters of the test tubes, D are 0.51mm and 0.30mm. First, two-phase frictional pressure drops were measured in adiabatic conditions, and compared with the correlations for conventional tubes. The frictional pressure drop data were lower than the correlation for conventional tubes. However, the data were in accord with those for conventional tubes qualitatively, and correlated in the form Φ_L²-1⁄X_tt. Next, heat transfer coefficients were measured in conditions of constant heat flux, and compared with those for conventional tubes. The heat transfer characteristics for min-tubes were different from those for conventional tubes, and so complicated. The heat transfer coefficients for D=0.51mm increased with heat flux, but were almost independent of mass flux. Although the heat transfer coefficients were higher than those for a conventional tube (D=10.3mm) in low quality region, they decreased with quality. The heat transfer coefficients for D=0.30mm were higher than those for D=0.51mm, and almost independent of both mass flux and heat flux.

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It is known that small quantities of surfactant additives can greatly reduce the friction factors during the flow of a heat transfer medium. The friction factors are reduced because the generation of turbulent vortices is suppressed by the formation of rod-like micelles, and the flow remains laminar in the high Reynolds number range. However, the values of heat transfer coefficients decrease during flow laminarization; as a result, heat exchangers with a larger heat transfer area will be required. The research objective is to study the heat transfer enhancement effect of air injection. This paper presents an experimental investigation of the heat transfer and flow characteristics of an air-surfactant solution two-phase flow through a vertical tube. In the experiment, air was injected through a porous metal or a T-joint. The experimental results are as follows. In each air-inlet condition, heat transfer coefficients were enhanced drastically with the injection of air into a drag-reducing surfactant solution flow. In the case of air injection using porous metal, the flow patterns were almost bubbly flow at all flow rates. With regard to the enhancement rate of heat transfer coefficients, air injection through porous metal was more effective than that through the T-joint. This result shows that the apparent concentration of the surfactant solution in the bubbly flow was considerably less than that in any other flow patterns, because the surfactant molecules were concentrated at the bubble-water interface.

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We have investigated a method to evaluate fatigue damage of mild steels without contact using laser. In high cycle fatigue of mild steels, we used a laser spot beam illuminating the fatigue damaged point of a specimen surface and observed diffusion pattern change of the reflected light from the specimen surface due to surface change by slipband in the previous work. This method was a point method observing at a point where spot beam is illuminating. In this paper, we tried to detect fatigue damaged area in the full field of the observing area with a CCD camera and evaluate fatigue damage using an optical setup with a laser slit beam. The results showed that there is a possibility of detecting fatigue damaged area and also evaluating fatigue damage by this optical setup. Full-field visualization and evaluation of fatigue damage is possible by scanning the slit beam on the specimen surface and observing reflected light pattern of the slit beam. There is also a possibility to predict a position where final fracture occurs based on the distribution of evaluated fatigue damage inside the fatigue area.

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An iterative method for determining three-dimensional coordinates of a planar object surface from a pair of images obtained by a stereovision is proposed. The three-dimensional coordinates of an object surface are obtained from the pair of the image coordinates of the corresponding points. Then, the camera parameters are refined using the coordinates of the object surface. Repeating this procedure, the accurate three-dimensional coordinates of the planar object surface are obtained. The effectiveness of the proposed method is validated by evaluating the three-dimensional coordinates of a planar board. In addition, the proposed method is applied to the measurement of the crack tip displacement fields and the subsequent stress intensity factors evaluation. Results show that the accu-racy for determining three-dimensional coordinates of a planar object is improved by the proposed method.

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Magnetic functional fluids contain many magnetic particles. When the magnetic functional fluids including both micrometer size magnetic particles and nanometer size magnetic particles are used for the damper, the damping properties are affected by mixture ratio of them. The magnetic functional fluids including much micrometer size magnetic particles has large damping force. However the micrometer size magnetic particles sink immediately. Therefore, in this study, damping properties of a damper using magnetic functional fluids including both micrometer size magnetic particles and nanometer size magnetic particles are investigated experimentally. The magnetic functional fluids include thickener to prevent the magnetic particles from sinking. It is shown that the damping force, the absorption energy and the response of damping force are affected by the composition of the magnetic functional fluids.

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It is considered that there are two factors for polymer crystallization. One is crystallinity which is calculated by ratio of crystal and amorphous part, the other is crystalline state which represents interior morphology. Thus, adjustment of crystallinity and crystalline state was performed. As a result, crystal of POM is made up with spherulite. At first, crystal nucleation was observed. After then, crystalline growth occur radially from crystalline nucleus. It was understood to be able to make the sample with a different spherulite size by non-isothermal crystallization which means changing of cooling rate from melting condition. The other hand, crystallinity was increased with holding time remaining the shape of spherulite by isothermal crystallization. On each material, Arrhenius type of time-temperature superposition principle was confirmed on creep test. Creep behavior was suppressed with crystallinity by comparison between creep curves. However, it was confirmed that the shape of master curves are different between materials with different crystal grain size, because response of creep deformation to time passage is not same. Therefore, it was found that Grand master curve was obtained under the terms of same crystalline state, and it was able to estimate long term creep behavior on materials of arbitrary time, temperature and crystallinity.

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