Jet-induced rotary sloshing in a partially filled cylindrical container is numerically simulated to investigate a global feature of occurrence process. Visualization technique em-ployed in this study includes Computational Fluid Dynamics (CFD). A simple physical model is also established on the basis of the numerical observation for the time develop-ment of the amplitude, the centre-line velocity of the inlet jet, and the time history of the vertical velocity profile. The proposal model gives the global feature of the occurrence process and exhibits good comparison against the previous experimental results.

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The cross flow fan has an eccentrically located vortex inside impeller. The vortex behavior has a large effect on the fan performance and fan noise. Although investigations on the internal flow of cross flow fan have been performed by many researchers, quantitative relationship between the eccentrically located vortex and fan noise is not sufficiently made clear. In our previous study, we developed a noise reduction method of cross flow fan by using a step tongue and a skew tongue. Unfortunately, a detailed mechanism of fan noise reduction is not known yet. In this paper the flow pattern and the fan noise of cross flow fan are experimentally and numerically examined.

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The desulfurization process is of essential importance for producing clean steel. Desulfurization agents such as CaO particles are usually injected into the reactor of the process together with carrier gas.
Three types of gas injection systems are employed in the current metals refining processes: bottom gas injection, lateral gas injection, and top lance gas injection. In the desulfurization process, gas is usually injected into the molten iron bath in the horizontal direction or downwards.
In this study particular attention is paid to horizontal gas injection through a multi-hole nozzle attached to the top lance. The inner diameter of the nozzle is changed over a wide range. Two types of bubble formation patterns are observed depending on the gas flow rate: synchronized and non-synchronized bubble formation patterns. The frequency of bubble formation at each hole is measured with a high-speed camera. A previously proposed empirical equation for the frequency of bubble formation is modified to take the inner diameter of the nozzle correctly into consideration.

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Turbulent flows in pipes are usually accelerated from rest using blowers and pumps in practical applications. The history of cross-sectional mean velocity consists of the initial stage of flow acceleration and the subsequent stage of constant cross-sectional mean velocity. The effect of the initial acceleration on the transition to turbulence in such flows is not fully understood yet. In the present study experimental investigation is carried out to reveal this effect in a circular pipe using air as the working fluid.

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The aim of this study is to numerically and experimentally investigate dynamic behavior of a droplet impacting and bouncing on an inclined plate under various wettability conditions. The visualization techniques employed include Computational Fluid Dynamics (CFD) and experimental observation with a high-speed camera. The present computational model is verified for a droplet impacting on a horizontal plate. The dynamic behavior of a droplet bouncing on an inclined plate is then observed under various high-hydrophobic conditions. This paper presents some results for snapshots of bouncing motion, trajectory, the coefficient of restitution and the deformation rate at the impact on the plate.

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The effect of an abrupt expansion on the flow pattern of air-water two-phase flow in a millimeter-scale rectangular channel was investigated. The channel height was fixed as 0.19 mm, 0.50 mm, 1.00 mm and 2.00 mm. The expansion ratio was 5, 2.5, 1.67 and 1.25 for every channel height. The superficial velocity of air was varied from 5.0 cm/s to 80.0 cm/s and that of water was varied from 10.0 cm/s to 80.0 cm/s. As a result, a flow pattern with recirculation zone was observed in the channel height of 2.00 mm and 1.00 mm. This is the same pattern as that in the conventional scale pipes and ducts with an abrupt expansion. Furthermore, there was no effect of an abrupt expansion on the flow pattern when the expansion ratio was close to unity. On the other hand, in the channel height of 0.19 mm, each bubble spread in the lateral direction after it passed through the abrupt expansion. This is an interesting phenomenon in the small channel height.

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The dynamic behavior of water droplets on a vibrating solid surface was investigated experimentally. The liquid drop responses were examined by two vibrating methods. At first, the dynamic behavior of a water droplet on the solid plate subject to vertical vibration was investigated. In this experiment, an electrodynamic shaker was operated to generate the vertical vibration. Secondarily, the dynamic behavior of the magnet-magnetic fluid element on the plate subject to the vertical vibration was investigated because of the comparison with the behavior of water droplet. Thirdly, liquid atomization by ultrasonic vibration was investigated with a surface acoustic wave device. The dynamic behavior of water droplets on the vibrating plate was analyzed by a high speed video camera system. It was found that the water droplet responds to the excitation in elongation and contraction (axisymmetric modes) at lower excitation accelerations. With increase of excitation acceleration, the water droplet showed the polygonal oscillations (polygonal modes). The water droplet was completely atomized by the ultrasonic vibration using the surface acoustic wave device.

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We propose two kinds of mechanical agitation methods to replace the conventional centric agitation method: offset agitation and centric agitation with an immersion cylinder. Particle Image Velocimetry (PIV) measurements are carried out to investigate the flow patterns in the bath agitated by these methods with an impeller often used in hot metal pretreatment processes. Low-density particles are most widely dispersed into the bath by centric agitation with an immersion cylinder.

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The behavior of a single bubble rising near a plate orifice placed in a vertical pipe is studied. The effect of the surface wettability of the orifice hole on the behavior of the bubble is examined in detail. A change in the bubble shape near the orifice is observed with a high-speed camera and the bubble rising velocity is determined from the images recorded on a PC. A single bubble tends to preferably attach to the orifice hole with an increase in its volume and stays there under specific conditions regardless of the wettability of the orifice. Two different prediction methods are proposed for the conditions.

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The effect of operating pressure on freeboard temperature distribution, which has a strong effect on N₂O emission, in a pressurized fluidized bed incinerator of sewage sludge, was estimated by a computational analysis and compared with experiments. A local high-temperature zone was found to appear in the freeboard under the pressurized conditions in the combustor. This suggests the substantial reduction of N₂O concentration in the high-temperature zone due to N₂O destruction reaction.

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A theoretical model was proposed to consider the dynamic contact angle from a macroscopic viewpoint. A slight convex profile of liquid surface is assumed to avoid the divergence of viscous stress near the three-phase contact line on the wall. The theoretical results of the dynamic contact angle are dependent on the parameter ε, i.e., the ratio of surface area occupied by the defects on the solid surface. The movement of liquid column in a capillary is investigated experimentally. The modified Lucas-Washburn equation including the effect of dynamic wetting represents well the measured results. The theoretical model can approximate the measured dynamic contact angles within the experimental uncertainty.

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An experimental and theoretical study was conducted to investigate the characteristics of liquid film flowing around a horizontal circular cylinder. The standing wave with a peak line pointing to the flow direction appears on the film surface. The wave length was obtained theoretically from the force balance on the film surface including the effect of centrifugal force. The calculated wave lengths agree with those measured experimentally for three kinds of test liquids. When the film Reynolds number increases larger than 500, the viscous effect on the wave motion can be neglected.

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The three-dimensional flow characteristics of a new hybrid vertical axis wind turbine have been investigated by conditional sampling stereoscopic PIV^* in order to clarify the three-dimensional motions of the upper surface flow at the edge of the turbine blade which is moving perpendicularly to the flow. The experimental apparatus is constructed using the PIV measurement system with a conditional sampling device and a new hybrid vertical axis wind turbine installed in a circulating water channel.

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This study is a first step in developing a three-dimensional separation and classification system in a minichannel in which 60 electrodes are embedded in a three-dimensional arrangement. Particle velocities driven by the dielectrophoresis (DEP) force are measured in a simplified minichannel with electric field intensities from E=±1 V/mm to ±5 V/mm, electric field frequencies from ƒ=1 kHz to ƒ=1 MHz, and particles with diameter of d=1.3 μm, 1.5 μm and 2.0 μm. Both the DEP force and the particle velocities increase as the particle diameter increases. In addition, particles have higher velocities when higherelectric field intensities are applied.
Electrodes two dimensional are used for DEP in the research of the past. Moreover, the plane electrode of the wedge place is used to generate DEP positively. The possibility of a three dimensional operation was confirmed by using the parallel plate electrode array in this research.

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In this research we have tried to apply the CARS method to the measurement of vibrational and rotational temperatures with radiation behind the strong shock wave, and have also used high-speed camera to obtain 2D image of total radiation. The strong shock waves are generated by a free-piston, double-diaphragm shock tube with low-density test gas. As the results, CARS measurement for vibrational and rotational temperatures of hypersonic flow behind the strong shock waves has been satisfactorily established over 5km/s shock velocity. We also succeeded to acquire the ultra high-speed 2D image of total radiation of hypervelocity flow with strong shock waves.

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Two experiments were performed using scale models of air lifting towers placed in a cubic water tank. The scale models were equipped with different diffusers forming various bubble plumes, which included 4 continuous and 2 intermittent types. First, flow distribution was measured by a PIV and the efficiency of water entrainment was determined. Second, the rate of oxygenation by aeration was measured and the oxygen transfer coefficient could be calculated. As a result, it was apparent that the 4 continuous types had higher performances than the 2 intermittent types.

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The flow and heat transfer control to improve the performance of fin-tube type heat exchanger under large Reynolds numbers is shown. A louver type vortex generator was used because of it's high heat transfer characteristics, and the effect of louver angle, attack angle or raising angle, was examined mainly. The effects of the flow and heat transfer characteristics around and on the tube and fin plate were made clear by flow visualization, Particle Image Velocimetry (PIV) measurement, and temperature distribution measurement by thermo-graph. As a result, the maximum improvement rate of heat transfer is about 86% of the flat plate, plane fin.

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Using confocal microscopy, we studied the individual motion of fluorescent platelet-sized latex beads suspended in glycerol-PBS solutions, flowing through a narrow gap of 80 μm width in a PDMS-conical channel with a round ball inside. The trajectories and the velocity profiles of the beads were investigated in the gap region, in the absence or presence of red cells at hematocrit 1%. The presence of red cells enhanced the fluctuations of the bead velocities and often deflected their trajectories from the streamlines of the suspending fluid, especially near the channel wall.

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The bouncing motion of a solid particle on a wall in the water is different from that in the air because the water influences the particle motion more than the air. In order to investigate such effect of the water on the solid particle, bouncing behavior of a cylinder in the water was studied by image processing. In the experiment, an apparent coefficient of restitution of the cylinder was not unique, that is, it was influenced by the velocity and the rotating angular velocity of the cylinder. The velocity fields of the water suggested that the water flow around the cylinder played an important role on the bouncing motion.

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A simple method for calculating strain distributions on a three-dimensional surface from measured displacements is proposed in the present study. Displacement components within a small region on the three-dimensional surface are transformed into the displacements on a local Cartesian coordinate system. The displacements on the local coordinate system are approximated by polynomial functions using least-squares. Strains within the small region are then obtained from the coefficients of the approximated functions. Repeating this procedure for the whole field, the distributions of the principal strains are obtained. The effectiveness of the proposed method is validated by applying the method to the displacements obtained by finite element method. Then, the application of the method to the surface strain measurement of human face is demonstrated. It is shown that the proposed method is a powerful and efficient tool for data reduction because the strains on a three-dimensional surface are obtained simply and easily by the proposed method.

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We have developed a new method for observation of cylindrical surfaces. The cylindrical surfaces were observed using a laser microscope with a wide field of view. When cylindrical specimens are rotated by a motor-driven rotary table, the focused laser light is scanned along a generatrix of the cylinder surface. Thus, the whole cylinder surface can be observed easily even over a very short period. As the obtained image is a developed view of the cylinder surface, it is easy to measure the distance between any two points on the cylindrical surface.

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A stress analysis method for a model with initial stresses is presented, herein referred to as a residual stress model. The stresses applied to the residual stress model are obtained from two resultant stresses by applying loads of different magnitudes. The residual stress model used to test the proposed method is a circular disk with frozen stresses that is subjected to a diametral compressive load at an angle of 31°. The applied stresses and residual stresses on the model were precisely obtained by numerical simulations using the proposed method.

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A new heating technique with a stainless steel film and a nondestructive inspection system with the response surface method resolve some of the issues of active thermography. A black painted stainless steel film works as a blackbody surface. As a result, an infrared thermographic camera can easily measure the temperature of a metal surface accurately. The inspection system can identify the shape of the local thinning robustly by selecting the attribute for the shape parameters.

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A fundamental study on a method that uses electrodeposited copper foil to measure cyclic compressive load was carried out in this report. When copper foil is adhered to the side of a cylindrical element inserted in a contact area, grain growth is caused by cyclic compressive stress. A basic equation among grain growth density, compressive stress amplitude and number of cycles is derived in this report. If the increasing rate of grain growth is arranged by compressive strain amplitude, the relationship between them does not depend on the material of the cylinder. If some materials are chosen as the cylindrical element, the grain growth occurred in a wide range of compressive stress amplitudes. This means that a wide range of compressive load can be measured without changing the shape of cylindrical element.

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To improve the delamination energy of a sputtered SiC film deposited on a tool steel substrate, conical precipitates were formed on the surface of the substrate prior to the SiC coating using a sputter-etching method proposed by the authors. A micro edge-indent method was employed to evaluate the delamination energy of the SiC film. The results showed that the precipitates remained on the delamination surface when the height and the dispersion were small. The load at delamination of the sputter-etched specimens exceeded that of an un-etched specimen for small indentation distances from an edge, but was less than that of an un-etched specimen for large indentation distances from the edge. The delamination energy of the specimens with small precipitates exceeded that of the un-etched specimen due to an anchor effect.

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The in-plane tensile properties of commercial paperboard and cardboard for packaging containers or cartons are characterized using both a compact testing machine equipped with a non-contacting optical extensometer and a high-speed digital image sensor. Uncoated white paperboard and two kinds of coated water-resistant cardboard are tested in a controlled standard atmosphere. Thin strip tensile specimens are cut on a paper cutter at five different orientation angles between machine direction (MD) and cross-machine direction (CD). The in-plane Young's moduli, Poisson's ratios and tensile strengths as a function of orientation angle are measured and compared with theoretical predictions from both the orthotropic elasticity theory and the Tsai-Hill failure theory in composite materials. It is shown that the orientation dependence of the in-plane tensile properties can be explained using composite theories.

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A defect in a pressurized pipe was visualized by using mechanoluminescent (ML) sensor. In the present work, the hoop strain distribution on the outer surface of a defective pipe was obtained by ML intensity measurement and strain gage measurement. Additionally, a FEM calculation was also performed and compared with the experimental results. The hoop strain distribution obtained from the ML intensity agreed well with that obtained from the strain gage measurement and the FEM calculation. It was found that the hoop strain on the defective pipe had maximum and minimum values around the defect and the maximum hoop strain increased with deepening the defect. These results indicate that the location and depth of the defect in a pipe can be estimated by using the ML sensor.

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A new method for accurately determining the absolute fringe orders of isochromatics from color photoelastic fringes obtained using a plane polariscope was developed. This method uses a set of five color photoelastic images, which are obtained at five sets of angular positions of the polarization plate in dark- and light-field polariscopes. The effectiveness of the method was investigated with the simulated color photoelastic fringes of a circular disk subjected to a concentrated load. Results showed that the method is effective for determining the absolute fringe orders.

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A simply supported beam which has analytical solutions (deflection and stress distribution) is analyzed as Rapid Prototyping (RP) model. The beam is made of acrylic transparent resin and tracer particles are uniformly dispersed. The deflection of the beam is obtained by each dispersed particle's positions between unloaded and loaded beam. Three-dimensional position of the tracer particle is measured by digital holography. In order to suppress the different refractive index between the beam and surrounding air, the beam is installed in the water tank which is filled with a refractive-index matching liquid. The same RP model is repeatedly observed at the same condition. Experimental results on the three-dimensional deflection and stress field and the measurement accuracy are presented.

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High strain-rate compressive response of friction stir welded AA6061-T6 joints in the thickness direction was examined using the conventional split Hopkinson pressure bar. AA6061-T6 sheets of about 5 mm in thickness were friction stir welded in the butt joint configuration. The friction stir welding conditions were varied by altering a welding speed, keeping a rotational speed constant. Micro-hardness tests were conducted across the centerline of FS welded joints to identity the microstructural change. Cylindrical specimens machined along the thickness direction of both FS welds and the base material were used in the low and high strain-rate compression tests. The low strain-rate tests were carried out in an Instron testing machine. The effects of strain rate and welding speed on the flow stress and strain hardening rate of both the FS welds and the base material were studied.

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A split Hopkinson pressure bar (SHPB) technique has been developed to study the dynamic behavior of materials having low characteristic impedance. To obtain better matching with low impedance specimens, polymethyl methacrylate (PMMA) bars are used as the input and output bars. The viscoelastic properties of PMMA are determined in advance through preliminary wave propagation experiments. In the present SHPB method, the wave analysis of the stress pulses is conducted in the frequency domain. The incident, reflected and transmitted pulses on the PMMA input and output bars obtained from a SHPB test are resolved into frequency components using the Fourier transform, and corrected to obtain the waveforms at the specimen-bar interfaces. The dynamic viscoelastic properties of the specimen are subsequently determined based on the corrected waveforms. The proposed SHPB technique is then applied determined the viscoelastic models for core and cover materials of a 2-piecegolf ball. The complex compliance for each material is determined as one of the viscoelastic properties in the frequency domain. Furthermore, it is verified through the FEM simulations on the impact of golf balls that the proposed SHPB method provides reasonable estimates of the dynamic behavior of low impedance materials.

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Carbon fiber reinforced plastic (CFRP) laminates are used in various industrial fields because they have excellent properties such as a specific strength and a specific stiffness. The use of CFRP in the manufacture of automobiles can lead to a significant reduction in automobile weight, thereby improving the vehicle mileage as well as reducing CO₂ emissions. On the other hand, the issue of passenger safety in case of collisions should also be clarified when employing CFRP in the fabrication of automotive structures. The objective of this study is to establish a simulation technology for investigating the impact response behavior of rectangular CFRP tubes, which were equipped with two ribs, under full-lap collision conditions. We performed drop weight impact tests to investigate the impact response behavior and impact energy absorption characteristics of the developed CFRP tubes; the tests involved dropping an impactor from a height of 12 m so that the impactor speed just before impact was approximately 55 km/h. A finite element (FE) model was also developed by using the nonlinear, explicit dynamic code LS-DYNA to simulate the impact response behavior of the rectangular CFRP tubes under impact loading. With regard to the load-displacement curves, the experimental results showed a good agreement with the FEM results. The maximum load, absorbed energy, and final displacement calculated by the FEM model were in good agreement with the corresponding average values obtained from the impact test results.

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Shape measurement is required in factory automation. An exemplary application is bin-picking. As one type of a contactless measurement method, phase-shifting methods in which a grating pattern is projected are known. A compact, lightweight device is required for projecting the grating pattern inside production equipment. As a compact, lightweight projector, a MEMS (Micro Electro Mechanical Systems) scanner grating projector is proposed. However, the projected pitch is not uniform in whole projected area because the pitch is changed according to the angle of the 1D MEMS scanner. Calibration is therefore important. We have developed a shape measurement system using the whole-space tabulation method (WSTM) with the MEMS scanner grating projector. The influence of the change of the projected grating pitch is eliminated with the WSTM. In this paper, the shape measurement system was applied to bin-picking with a robot hand and its effectiveness was confirmed.

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The durability of fiber-mixed planting soils with wood chips for soil erosion by rainfall was experimentally investigated. It was confirmed that the durability of fiber-mixed planting soils with wood chips for soil erosion by rainfall is larger than that of bark materials which are generally used for planting on the slope. The amount of sediment discharge increased with increasing the slope angle and showed a maximum at a certain slope angle. However, it was confirmed that the amount of sediment discharge by rainfall decreased at high slope angle.

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The influence of the body-metal powder size on the microchanneling behavior and the lining-layer formation in the powder-metallurgical microchanneling process was investigated using the combination of iron powder and copper wire. Iron powders 45 μm and 110 μm in average diameters were examined. Open microchannels and clear lining layers were formed in all specimens. The coarser iron powder tended to reduce the homogenization rate of the composition of the lining layer.

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We propose the concept and fabrication method for a novel transpiration-cooling device. The device consists of an open-porous metal and contains microchannel networks. Cooling water is supplied from the tank to the every corner of the device through the microchannel networks and then seeps out to be vaporized absorbing the latent heat. The porous body of the device and the microchannel are produced by a powder-metallurgical microchanneling process. We investigate the influence of the porosity of the compact specimen on the seeping behavior of cooling water.

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Fabrication of a nanoporous anodic oxide film on the inner wall of a microchannel was experimented. The microchannel was produced in a titanium body by a powder-metallurgical microchanneling process and was lined with a Ti-Al alloy layer. We found an appropriate anodic condition for an exposed planner surface of the Ti-Al alloy layer. In the case of the microchannel, the growth of the nanoporous oxide film tended to retard deep inside the channel. This problem was easily solved by lengthening the anodic oxidation time.

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We have investigated the electrochemical formation and phase control of La-Ni alloy films in LiCl-KCl eutectic melts added LaCl₃ (0.50 mol%) at 723 K.
Open-circuit potentiometry was carried out with a Ni electrode after depositing La metal by potentiostatic electrolysis at 0.40 V (vs. Li⁺ / Li) for 60 s. There were four potential plateaus at (a) 0.52 V, (b) 0.62 V, (c) 0.75 V and (d) 1.42 V, respectively. The observed potential plateaus were considered to correspond to different coexisting La-Ni phases, respectively. Based on the result of open-circuit potentiometry, an alloy sample was prepared by potentiostatic electrolysis at 0.48 V for 1 h at 723 K. From the XRD pattern of the sample, the alloy phase was identified as only La₇Ni₁₆.
In order to form various La-Ni phases, selective anodic dissolution of La from the formed La₇Ni₁₆ film was conducted at 0.58 V, 0.68 V, 1.00 V and 1.80 V, respectively. The La₇Ni₁₆ film with thickness of 3.5 μm was prepared by potentiostatic electrolysis at 0.48 V for 1 h. In the sample obtained at 0.58 V for 1 h, the existence of LaNi₃ was clearly seen. The alloy film had some pores, which was thought to be caused by the volume change during the anodic polarization. Phase of the sample obtained at 0.68 V for 1 h was La₂Ni₇ by XRD analysis. The La₂Ni₇ film also has some pores. The sample obtained at 1.00 V for 2 h was found to be LaNi₅. The obtained film contained more micropores than the LaNi₃ and La₂Ni₇. The sample obtained at 1.80 V for 2 h was delanthanized to Ni. The obtained film was about 3.0 μm and had a porous structure.

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The equilibrium relation of the phase separation in the Fe-Cu-B system is investigated more in detail at the lower boron content at 1873K. By combining the Taylor series equation proposed by Wagner and that of the quadratic formalism proposed by Darken, the thermodynamic interaction parameters of copper and boron in molten iron are derived. As a result, it is confirmed that two liquid phases separation occurs even at the lower boron content in iron, [mass%B]_{(in Fe)}=0.006. The interaction parameters of copper and boron in molten iron at 1873K are derived.

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The rate of nitrogen transport from molten iron to the gas phase through a CaO-Al₂O₃ melt was investigated and we propose a mixed rate determining equation. We found that it is important to keep the oxygen partial pressure in the gas phase high and the oxygen potential at the oxide melt/metal interface low for efficient nitrogen transport. From the derived equation, we also considered that nitrogen transports from the oxide melt to the gas phase even at a high nitrogen partial pressure in the gas phase.

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

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In vivo contact areas of tibiotalar joints in 20 healthy subjects were studied using a loading device within a closed-MRI system. Cartilage-enhanced, sagittal images were obtained at 10° of dorsiflexion, and 0° and 10° of plantarflexion under 200 N ankle-loaded conditions. For ankle-unloaded conditions, the ankle was positioned at 10° of dorsiflexion, and 0°, 10°, 30°, and 50° of plantarflexion. This study highlights the differences in tibiotalar joint contact area between different ankle flexion postures, loading conditions, and geometries of joint surfaces.

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Ankle.foot orthoses (AFOs) are orthotic devices for the disabled people, for example, those suffering from hemiplegia or peroneal nerve palsy, to support the movements of the ankles. We have developed intelligently controllable AFOs (i-AFO) in which the ankle torque is controlled with a compact magnetorheological fluid brake (CMRFB). In this paper, we propose a novel prototype of the i-AFO, in which the sensor system, the build-in CMRFB, the gait estimating method and torque control method were improved from those of the previous prototype. Gait-control tests with the novel i-AFO were performed for a patient with flaccid paralysis of his ankles. According to the experimental results, the estimation of the gait state and the velocity control in the initial stance phase were concurrently carried out.

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Currently, stem insertion during total hip arthroplasty (THA) is not well controlled. The present study investigated a method for improving stem setting in accordance with preoperative planning using a three-dimensional (3-D) computed tomography (CT) model of the femur and RGB images of the excised femoral head. We utilized three femoral heads removed during THA and modeled each head using three spherical acrylic markers. Each femoral head was osteotomized using a parallel jig and three rectangular images of the osteotomized head were taken using a CCD camera. Each femoral head was then set on a camera base and RGB images were taken from three orthogonal directions using the CCD camera. The B-images of the femoral head and the 3-D bone model were processed through image-matching software using an automatic outline extraction and downhill simplex method. The position of the contralateral side of the jig, related to the femur, was measured using a 3-D measuring system in order to validate the accuracy of the image-matching. However, since validation of the accuracy of the image-matching is difficult once the femoral head is excised, a six-degree-of-freedom board was used to facilitate the accuracy validation.

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Estimation of the artificial hip joint contact area and pressure distribution during motions of daily life is important in predicting joint degeneration mechanism and implant wear. The purpose of this study was to develop a method of applying discrete element analysis (DEA) based on a rigid body spring model to artificial hip joint, and to analyze contact area and pressure distribution during different motions. Post-operative motion analyses of four basic motions, such as fast walking, slow walking, standing up and sitting down were performed by using VICON system and Kistler force plate. Implant orientation was obtained by matching the contours of 3D bone model and implant CAD model to those of the biplanar CR images. Triangular mesh at interior surface of cup model was considered as liner surface and used for applying DEA to artificial hip joint.Because stem model was considered to be a rigid body and consequential transformations occurred only inside the liner model, triangular mesh was considered to be a compressive spring respectively.The change of contact area and the pressure distribution under dynamic condition were calculated easily through these considerations, and rapid increase accompanied with change of area was observed in knee bending motions.

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An objective of this study is to investigate the influence of an amount of mixture of hydroxyapatite (HA) granules and morsellised cancellous bone (MCB) on the initial stability of reconstructed acetabulum through mechanical testing. Reconstruction was carried out using impaction bone grafting technique with four mixture ratio, then, cyclically loaded as a simulation of the motion of gait and analyzed the migration. The initial stability is highly dependent on mixture ratio and larger HA mixture ratio could give us better initial stability of the cup.

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The wrist joint is condyloid and capable of movement through two axes: palmar/dorsal flexion and radial/ulnar deviation. Knowledge of in vivo joint mechanics is important for understanding pathological mechanisms and the treatment of various joint problems. The purpose of this study was to investigate the in vivo wrist joint mechanism during wrist motion. In vivo wrist joint contact and the kinematics of the scaphoid and lunate during palmar/dorsal flexion and radial/ulnar deviation were examined using magnetic resonance imaging (MRI). The wrist joints of 15 healthy young volunteers were scanned at 8 positions (.30 deg of palmar flexion; neutral; 30, 60, and 90 deg of dorsal flexion; .20 deg of radial deviation; neutral; and 20 deg of ulnar deviation). Contact of the wrist joint was estimated quantitatively from the derived MR images. Using three-dimensional surface models of the carpal bones, the kinematics of the scaphoid and lunate were analyzed three-dimensionally.

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