Tooth displacement due to occlusal force was measured using X-ray CT images and coordinate transformation method. The two CT images of mandibular dentition were recorded without and with the occlusal force. The tooth displacement was evaluated from the two images by matching them at the mandibular bone region using the coordinate transformation method. The following results were obtained under the occlusal force of about 100N at the first premolar: (1) The displacement measurement of the tooth is possible using the present method. (2) The displacement was also observed at the teeth without occlusal force. (3) The displacement tended to be small in the direction of tooth axis but relatively large on the occlusal surface. (4) The absolute values of the displacement were less than several hundred micrometers in the tooth axis and were nearly one millimeter on the occlusal surface.

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A digital image correlation method was applied to study the swelling deformation of a light cure composite resin due to water absorption. Five specimens of stainless steel were fabricated by filling the resin into a cylindrical cavity prepared with a bonding agent. The specimens were irradiated using a visible-light curing unit and photographed with a CCD camera as reference images before deformation. The swelling deformation was analyzed using the reference image and evaluated by measuring the displacement fields on the free surface of the cavity as a function of soaking period into water, and the following results were obtained. The swelling deformation due to water absorption can be evaluated using the present method. The displacement distribution was continuous at the interface between the resin and substrate, and its absolute value exhibited the maximum in the resin close to the interface and the minimum near the center of the cavity. The deformation was increased largely in the early stage (about a week) of soaking period, then gradually increased in the middle stage (about 2-3 weeks), and tended to be saturated in the later stage (about 4 weeks) for the composite resin tested.

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A digital image correlation method (DICM) is a simply measurement method for the surface deformation using only digital images are taken by a digital camera and recently it will be used in many research and development fields. A new analysis method of strain distribution using the DICM will be developed in order to estimate residual stress. For the new analysis method using the DICM, the strain distribution around the hole in the plate will be estimated using the distance change between two points that symmetry with respect to a center point of the hole. In this paper, a strain distribution around the center hole in the steel plate and a strain distribution around the cutting hole in the concrete specimen will be measured to investigate effectiveness of this method.

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A method for measuring two-dimensional stress components is proposed. A two-dimensional birefringent specimen placed in a Mach-Zehnder interferometer is observed using a CCD camera equipped with a micro-retarder Array. The light emerging from the Mach-Zehnder interferometer contains the information of the principal stress difference, principal stress sum and the principal direction. The distribution of the Stokes parameters of this light vector is obtained from a single image since the CCD camera equipped with a micro-retarder array can record multiple information as a single image by a single exposure. Then, the distribution of the stress components can be evaluated from the Stokes parameters. It is expected that the proposed method can be applied to time-varying phenomena since multiple exposures are not necessary for the completion of stress analysis.

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For evaluating reliability of structures, it is important to know the distribution of displacement, strain and stress. In this paper, a hybrid sampling moiré method, which combines whole-field measurement technique, i.e. sampling moiré method, and finite element (FE) analysis is proposed for evaluation the stress distribution. The distribution of displacement measured by using the sampling moiré method is compared with the analyzed result based on elastic FE analysis at assumptive boundary conditions. The error between the displacement distribution of experimentally obtained and FE analysis is corrected so as to make it minimum by changing the boundary conditions such as loading force, loading position, etc. Experimental results show that the boundary conditions of loading force and loading position can be evaluated accurately using the proposed method. Once the appropriate boundary conditions are determined, three-dimensional distributions of strain and stress are easily obtained by FE analysis for evaluating reliability of structures.

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The polymerization shrinkage of a light cure composite resin, a dental restoration material, was studied using X-ray CT images and a digital image correlation method. An artificial cylindrical cavity in a bovine tooth was filled with the resin after spreading a bonding agent. The two CT images were recorded before and after irradiation of visible-light. The shrinkage behavior was evaluated from the two images by matching them at the bottom of the cavity floor. The result showed that a large deformation was caused on the top free surface of the cavity, suggesting that this surface deformation can decrease the contraction stress around the interface between the resin and tooth structure. The inhomogeneous shrinkage behavior was also observed from the internal displacement and strain fields of the resin.

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This paper relates to the feasibility of prediction of tornados. It discusses the environment and features of occurrence of tornados by Rawinsonde observation and Doppler radar observation. Here, we attempt analysis using infrared images of weather data showing cumulonimbus clouds etc. including terrain conditions. The 3D terrain of Hokkaido is displayed using digital data of elevation. In this case, the display of the terrain becomes clearer and the time for image display becomes faster by excluding ocean and lake areas. Here, the elevation of the 3D display of terrain is plotted on the Z-axis. Similarly, the brightness values of the image data of the weather satellite Himawari are plotted on the Z-axis. These are overlaid on the terrain to display an image in three dimensions. At that time, the low brightness values of the image are deleted. Due to this, display of high brightness, thick clouds is attained. Moreover, in the same region of terrain and weather data, compared with terrain data, weather data has fewer pixels and is coarser, so the data is linearly interpolated and a Fast Fourier Transform is used to prepare a Fourier series approximation curve to thereby increase the resolution of the image 3-fold. Here, the weather data on the terrain of Hokkaido on November 7, 2006, between 12:00 noon and 2:00 pm when a tornado occurred in Saroma-cho is analyzed and the change of the image on the terrain is considered.

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In this paper, an attempt is made to correlate the material ductility under tensile⁄shear loadings and the pore size in a cast aluminum alloy by sufficient experimental data. Thirty conventional tensile tests on round bar specimens and thirty shear fracture tests on butterfly-like flat specimens are conducted. Pores on each fracture surface are identified using a scanning electron microscopy and characterized in terms of the projected area of the largest pore, the chord length of the largest pore, and the total area of all of the pores on each fracture surface. It is found that the correlation between the tensile fracture strain and the area of the largest pore can be well correlated with a linear function, compared to the total area of all pores and the chord length of the largest pore. Meanwhile, this study reveals that a power function gives a reasonable fitting for the shear loading case in terms of the area of the largest pore.

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Recently, the machines of compact, high performance and silent type are desired. As for pumps, the extremely small sized type is needed for cooling devices of electronics. Therefore the space of installing the impeller is severely restricted. In that case, the friction type pumps (disk pumps) are highlighted which are constructed only by disks. The disk pump is very silent and causes small vibration, whereas its performance is not so high because of no blade. In this paper, the performance characteristics of single disk pump and multi disk pump are examined. The number of disks and gap size between disks are changed systematically.

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High quality steel has recently been required in many industrial fields. One of the typical impurities contained in molten iron is sulfur. Some desulphurization processes have been developed to decrease its content down to very low level. Desulfurization chemicals such as CaO powder are introduced into a molten iron bath by mechanical agitation or by powder injection with carrier gas. In this research attention is paid on the powder injection. The chemicals are commonly poorly wetted by molten iron, and accordingly, the carrier gas attaches to the surface of each particle in the course of penetrating into the bath. The buoyancy force acting on the particle reduces the penetration distance in the bath and lowers the efficiency of the process significantly. Model experiments are carried out on the influence of the surface roughness of a sphere on the penetrating behavior of the sphere in a molten iron bath, because the surface of the desulfurization chemical particles is usually rough. The roughness is measured with a laser microscope.

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Model investigation is carried out on the dynamic behavior of pork bones in a cylindrical bath agitated by a liquid jet. A spherical particle made of acrylic resin is used as a model for cut pork bone. Many acrylic particles are placed on the bottom of a water bath and then the bath is agitated by an upward water jet generated from a centered bottom nozzle. The water thus injected in the bath is circulated with a pump to keep the bath depth constant. The number of particles lifted up into the bath and the mean circulation time of the particles floating in the bath are measured. Empirical equations for these two quantities are proposed.

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