In the present study, interactions between a single particle and a single Burgers vortex are observed by using 2DPIV measurements as elementary interactions for modeling particle-laden turbulent flows. We focus on the interaction between a Burgers vortex and wake structure generated by a settling particle. It is found that the interaction between the vortices shed from the particle and the Burgers vortex induces the large fluctuation in the circulation of the vortex. Moreover, fragmentation and mergence of the Burgers vortex core are observed.

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This study aims to introduce a new technique to measure the velocity distribution of the dispersed component of a vertical, upward, water continuous two-phase pipe flow. Here, it is proposed that measurements of the variation in the local conductance of the mixture can be cross correlated to determine the local velocity distribution of, for example, gas bubbles in water.
The measurements were conducted by using arrays of axially separated conductance sensors placed normal to the flow. Each array contained eight electrodes distributed over the internal circumference of the pipe carrying the flow. The arrays, were mounted at a known distance from each other along the pipe. Within each array, individual electrodes could be configured as either ‘excitation’, ‘measurement’ or ‘earth’. By changing the electrode configuration of an array the electric field sensitivity distribution associated with the array could be altered, thus changing the region of the flow ‘interrogated’ by the system. By cross correlating the output signals from these arrays, in various combinations, the velocity of the dispersed phase can be obtained at different regions within the flow, thereby enabling the velocity profile of the dispersed phase to be measured.
The sensitivity distribution associated with given electrode configurations has been investigated in a bench test. First the flow meter was filled with water, and then nonconducting rods were inserted into the flow meter at various spatial locations parallel to the pipe, the resulting change in conductance was measured.. The sensitivity distribution has also been simulated using COMSOL software. Agreement between experiment and theory was close to 1 %.

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The effects of the contraction area ratio CR on impinging jet characteristics are studied. It is found that the smaller CR provides better heat transfer performance reflecting its centerline velocity increase. The smaller CR, however, needs a more operation power because of its large flow resistance. Then, we proposed a cone orifice nozzle to reduce the flow resistance of the nozzle and showed that the cone orifice nozzles of α=5 and 15° have enhanced heat transfer rates under the same operation power of the common orifice nozzle of α=0°.

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This paper describes a new design of a local four-sensor probe which was used to measure the local velocity vector of the dispersed phase in a bubbly gas-liquid two phase flow. Based on the four-sensor probe signals, a new signal processing technique was also introduced. Reference data was obtained using high speed cameras to determine the optimum value for the threshold voltages relevant to the output signals from the four sensors on the probe. Groups of signals from the four sensors that were generated by the same bubble were identified but the signals from some bubbles were ignored by the signal processing scheme. After using the signal processing technique, the results have been improved compared with the results without the signal processing technique.

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A unique feature of the cross flow fan is the eccentrically located vortex inside the impeller which is thought to result in the fan's high performance characteristics. The position and the circulation of the vortex are affected by the casing configuration of the fan. The vortex behavior has a large effect on the fan noise level, as well as on the fan performance. The experiments presented in the present study show that the reduction of the fan noise level is possible by installing annular bands around the ends of the impeller. Two sets of annular bands were used. In addition to the measurement of fan performance and noise levels, spectral (i.e., frequency) analysis of the acoustic signal was also undertaken. Further, flow measurements were undertaken to determine the vortex center location and to ascertain the mechanism of the observed noise reduction. Furthermore, a commercial 3-D flow analysis software package, SC/Tetra version 7 (CRADLE Co., Ltd.), was used to analyze the flow in the fan, confirming variation in the location of the vortex center with the small geometry changes and thus, indirectly, the effect of the annular bands on the fan noise level and performance.

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Unsteady pipe flows such as oscillating flow, pulsating flow, and transient flow are frequently encountered in engineering fields. Significant effort has been devoted to understanding the basic characteristics of these flows. Experimental and theoretical studies of transition to turbulence, however, are rather limited and restricted to simple constant-acceleration pipe flows and pulsating pipe flows. Information on the transition to turbulence in flows with complex histories is not available. In this study attention is focused on an air flow in a pipe subjected to an initial constant-acceleration followed by an almost instantaneous switch to a constant-velocity condition. The final Reynolds number based on the constant velocity is greater than the critical Reynolds number for steady pipe flow. The time from the start of the constant velocity flow to the initiation of turbulence can be predicted by an empirical equation. This equation is derived in this study by taking the burst period into consideration. Information on this flow provides a better understanding of the effect of initial acceleration on the transition to turbulence

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To reduce the exhaustion of carbon dioxide in power plants, the operating technology for co-firing of woody biomass at existing coal-fueled power plants has come to attract attention. In the present study, it is assumed that the domestic forestry biomass transported from mountain regions is used as a fuel in pulverized coal fired power plants. The forestry biomass in Japan is the most promising domestic resource. However, most of the forests in Japan locate in the mountain region, and hence the overland transportation of biomass to the power station is indispensable. The pretreatment of semi-carbonization and chipping before transportation is effective in reducing the energy consumption for transportation of forestry biomass. The main purpose of the study is to clarify the comminution and combustion properties of the mixture of semi-carbonized woody biomass and coal. From the experimental investigations, the following results are obtained. (1) The comminution energy of mixture decreases with pyrolysis temperature. The increase in the biomass mixing ratio increases the comminution energy in the temperature range below 300°C. In the “W region” below 200°C, the density of wood exerts great influence on the comminution energy. (2) The estimation method of comminution energy based on the biomass mixing ratio, which is called “biomass mixing ratio method”, is compared with the experimental results. The comminution energy of the mixture is overestimated by the biomass mixing ratio method, when the woody biomass is mixed. The overestimation is due to the wedge effect induced by pulverized coal. The comminution energy of the mixture of coal and the semi-carbonized biomass for the pyrolysis temperature ranging from 200 to 400°C can be predicted by the biomass mixing ratio method. (3) The estimation method based on the work index of the Bond's Law is proposed. The experimental comminution energy can be estimated by using the empirical correlations of the work index within accuracy of ±30%. (4) In the case of mixing with the biomass produced by pyrolysis at a temperature below 200°C, the ignition delay time and the total combustion time linearly decrease with the biomass mixing ratio. The increase in the biomass mixing ratio causes the increase in the volatile gas, which leads to the improvements of ignitability and the decrease in total combustion time. In the case of mixing with the biomass produced by pyrolysis at a temperature of 400°C, the total combustion time is not affected by the biomass mixing ratio.

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A stripe shaped standing wave appears on the surface of liquid film flowing around a horizontal circular cylinder. The wave grows in the downward direction under the influence of centrifugal force. The amplification was theoretically investigated from the momentum equation on the wave peak. The results agree with those measured experimentally for three kinds of test liquids. The amplification ratio A is mainly dependent on a parameter Fr₀•R/δ₀ concerning gravitational and centrifugal forces, and slightly on the Reynolds number.

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The convective drying of glass-bead-packed beds containing sucrose/NaCl aqueous solution was examined at a wide range of steam partial pressures using room air to superheated steam at 160 °C. The sucrose distribution in the sample materials after drying was affected by the humidity of the drying media and the glass bead diameter. This indicated that the density gradient affected convection flow. The drying time of the sample material with NaCl aqueous solution at a steam partial pressure of 16 kPa (high-humidity air) was shorter than that under other conditions.

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We theoretically and experimentally investigated the effects of pore size distributions on heat and moisturetransfer in porous materials (B-1 and B-2) during drying. Experimental results showed that the mean moisture content of B-2 at the end of the surface evaporation period was lower than that of B-1 for the same gas flow conditions, and this value was affected by both the drying rate and moisture transfer properties of the material. From the critical moisture content of the experimental results, the moisture transfer coefficients of samples were estimated.

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This study deals with an experimental investigation of the flow boiling heat transfer characteristics of water in a helically coiled tube heated in a high temperature oil bath in relation to the steam generator of LMFBR. Time variations of the external and internal tube wall temperatures were measured under low quality conditions and the heat fluxes across the tube were calculated from the difference between the external and internal temperatures. A simple numerical analysis was made to evaluate the heat transfer coefficients at the external and internal tube walls and their time variations. The results show that the heat flux change is caused by the heat capacity of the tube and that its temporal behavior is quite different from the wall temperatures. This suggests that the deterioration of heat transfer caused by local dry-out on the wall surface results in peculiar changes of the wall temperatures and the heat fluxes.

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The purpose of this study is to make up a visualization measurement system using PIV in order to measure amply flow between plate fins in a fin-and-tube heat-exchanger in an air conditioner. A three times scale model made of transparent materials was used in this experiment. Water was used as a working fluid instead of air employed in an actual heat-exchanger to easily visualize flow. The water flow rate was set through the Reynolds number using the equivalent diameter for a rectangular channel between the plate fins as a characteristic length in order to keep the mechanical similarity of flow. The experimental results showed that the flow around the plate fins in the scale model can be visualized adequately for PIV measurement. Therefore, it is suggested that the measurement system completed is feasible and useful.

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A fast breeder nuclear reactor has been investigated to design the compact system and there, a length of an entrance region for a flowmeter may not be kept enough. In order to study the possibility of usage of an ultrasonic flowmeter in such a condition, measurement error and frequency characteristics of the flowmeter located downstream of an elbow were investigated experimentally and numerically. The minimum entrance length and the appropriate measurement plane were discussed.

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This paper introduces ultrasonic 3D position measurement system that will estimate the location of a wave source by triangulating its position based on a multiple-frequency continuous wave (MFcw) to three receivers fixed to an inertial frame of reference. The Typical application of this system is finding the location of the transmitter that may be fixed on CNC machine, a robot end-effector. The receivers have to be fixed in specific locations, the major source of the problems are in the installation/calibration stage since the receivers are usually distributed in space and finding their exact location entails using a separate 3D calibrating device which may or may not be as accurate as the location system itself. This paper presents a method to use the system itself to set up an inertial frame of reference and find out the locations of the receivers.

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In this paper, we report damping properties of a damping force variable damper using magnetic functional fluids having both micrometer- and nanometer-sized magnetic particles. The damping force, damping force-displacement curve, absorption energy, and the response of the damping force are affected by the mixture ratio of the magnetic particles of different sizes.

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The in-plane tensile properties of machine-made paper were determined using both a compact testing machine equipped with an optical extensometer and a high-speed digital image sensor. Three different kinds of paper were tested in a controlled. Constant-width strip specimens were adopted in the tension tests. Thin strip tensile specimens were cut on a paper cutter in five different orientations between machine direction (MD) and cross-machine direction (CD). The thickness of each paper was carefully measured with a high-precision digital micrometer under a constant pressure. The in-plane elastic constants and tensile strengths as a function of orientation were measured and compared with theoretical predictions from both the orthotropic elasticity theory and the Tsai-Hill failure theory in composite materials. It was shown that the orientation dependence of the in-plane tensile properties can be analyzed using composite theories.

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In this study, we developed a new type transport system utilizing the magnetic noncontact levitation due to superconducting pinning effect. We measured magnetic forces between a superconductor and a magnet. By contriving magnetic unit composed of opposed direction magnets and yokes, we obtained sufficient magnetic force for stable levitation of shuttle of the transport system. The new transport system developed in this study was demonstrated a great feasibility as a novel superconducting mechanical system.

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The deformation behavior of liquid-packaging bags containing liquid subjected to drop impact was observed using a high-speed camera and the relationship between the behavior and the pressure of the bags measured using pressure sensors was investigated. Results indicated that the liquid-packaging bags have characteristic constriction and bulging, whose degrees vary with time, and the variation in the shape of the bags can be explained using the variation in the pressure of the bags estimated on the basis of the water hammer theory.

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A new phase unwrapping algorithm for the automatic determination of the isochromatic parameter (absolute fringe order) from a single-color isochromatic image using the fringe gradient and RGB wavelengths techniques is developed. To evaluate the effectiveness of the proposed method, a single-color isochromatic image for a circular disk subjected to a concentrated load was used. Numerical simulation results showed that the proposed method yields accurate absolute fringe orders of isochromatics.

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Stress and movement in the curing process of ultraviolet (UV) curing resin illuminated by UV rays were simultaneously measured to investigate the relationship between the residual stress and the shrinkage of the resin. The stress was measured by a digital photoelastic technique in the manner of phase stepping, and the movement was measured from the movement of segments of string mixed into the resin. Results indicated that the directions of principal stresses of the resin in the curing process are related, to some degree, with the movement of the resin.

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A copper electroplating stress measurement method is applied to an element that changes the biaxial stress ratio in the stress cycle over time. We originally produced a fatigue testing machine capable of producing the combined stress state of rotating bending and static torsion. The critical shearing stress and the grain growth rate were almost the same for the plane bending test and the rotating bending-static torsion test. These results mean that the static stress that is superposed on the cyclic stress has no effect on grain nucleation and grain growth.

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Low-density particles can be widely dispersed into a bath in offset agitation or centric agitation with an immersion cylinder. The density of the particles significantly influenced the dispersion behavior of the particles into the bath. A penetration depth, a dispersion ratio and a total dispersion ratio are introduced for quantitative description of the dispersion behavior. The measured values of these quantities increased as the density of the particles increased. More particles descended near the bottom of the bath as the density of the particles increased.

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We verify effectiveness of the concept of powdermetallurgical free-form microchanneling with functional microchannel lining. It is based on a microscopic infiltration phenomenon during liquid phase sintering of a powder mixture of metals with different melting points. A shaped compound of an organic binder and a powder metal with lower melting point is used as the sacrificial core that gives the shape of the microchannel. The resultant microchannel is surrounded by an alloy layer, which is expected to have useful properties.

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The formation condition of swirling flow accompanied with air-core in discharging liquid in a reactor vessel from a nozzle was investigated through water-model experiments. The occurrence height position of air-core against the initial angular velocity of swirling water was calculated in both cases of centric and eccentric nozzle position, and the result was compared with the respective experimental ones. The same tendency was found between the calculated and the experimental results, and both results were in reasonable agreement. It is found that the larger the initial angular velocity of swirling water, the higher the water level at which air-core arises.

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Experiments to inhibit the dioxins formation in a combustion furnace were carried out by a centrifugation and recombustion method of fly unburned matters (fly carbonaceous matters (C^*)) in an exhaust gas at high temperatures.
Total dioxin's and Cl₅ benzene's concentrations in the exhaust gas have a good correlation with the number of the fly C^* remaining in the exhaust gas, and their concentrations increase as the number of the fly C^* rises. Total dioxin's and Cl₅ benzene's concentrations after the centrifugation and recombustion treatment by the present hot cyclone of a small size reduce to 10% and 20% of their initial concentrations in the exhaust gas from combustion furnace, respectively, in proportion to the decrease in the fly C^*.
The predictive equation of the partial separation efficiency at high temperatures obtained for the present hot cyclone of a small size indicates that the reduction ratios of dioxins and benzenes are much improved by using a cyclone of larger sizes and increasing the inflow velocity of the exhaust gas to the cyclone. The present centrifugation and recombustion method of the exhaust gas at high temperatures is expected to be effective for the actual incineration plants.

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In the combustion processes such as a municipal and an industrial waste incinerations, O₂ concentration in a combustion gas is considered to be one of the important parameters against formation and/or suppression of toxic dioxins/furans (hereinafter referred to as dioxins), but there are a few papers which discuss the relationship between dioxins concentration and O₂ concentration in a combustion gas. In the present study, the influence of the residual O₂ concentration in an exhaust gas on the concentration of dioxins formation has been investigated by combustion experiments at 1073 K with polyvinyl chloride (PVC) powder. The residual O₂ concentration in the exhaust gas has been changed widely from 0.1 to 35 vol% by varying the mixture ratio of O₂-N₂ gas compositions and/or the PVC feed rate. Dioxins concentration has the maximum value at the residual O₂ concentration in the exhaust gas of about 3 vol%, and their concentration sharply decreases in proportion to the rise in the residual O₂ concentration, but the decrease in dioxins concentration becomes very slow in the residual O₂ concentration more than 10 vol%. On the other hand, dioxins concentration decreases under the high reducing atmosphere with the residual O₂ concentration of 0.1 vol% and CO concentration of 2.5 vol%.

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This paper describes the hydrodynamic function of minute hairs of living creatures. Many living creatures have minute hairs on their bodies. The swimming analysis of small aquatic creatures and the sinking analysis of dandelion seed were performed using a digital high speed video camera system. Microscopic observation of swimming legs of small aquatic creatures and pappus of dandelion seed was conducted using a scanning electron microscope. Flow visualization around a opossum shrimp was conducted by slow shutter photographic technique. The role of minute hairs for hydrodynamic drag generation was revealed through these analyses.

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Dynamic nanoindentation was used to determine microstructural viscoelastic properties of single osteons and interstitial lamellae of rat cortical bone tissue. The effects of mineral, organic and water contents on macrostructural viscoelastic properties were also investigated. Compared to interstitial lamellae, the storage moduli of osteons were significantly lower; however, loss tangents were higher. The storage modulus and mineral content were correlated, and the loss tangent and the organic and water contents were linearly correlated.

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This paper proposes a noninvasive method for evaluating the state of a fractured bone using time-series analysis based on speckle interferometry. The fine speckle fringes generated at the fractured section are detected using a gradient-based method and a new evaluation index is contributed for monitoring the state of the fractured bone. A performance test using a test phantom and numerical analysis using a particle method reveal that there is a detectable difference in the proposed evaluation index between cases with and without a cutting plane in an internal object.

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The purpose of the present study is to develop a direct and accurate method for measuring knee kinematics by using single-plane fluoroscopy. The 3-dimensional (3D) position of the bone (in other words, the 6 degree-of-freedom (DOF) parameters) was recovered by matching the digitally reconstructed radiographs (DRRs) generated from the 3D volume model of the bone on the basis of the fluoroscopic image. The root-mean-square error (RMSE) of the overall rotation parameters was within 2.1 degrees. For the translation parameters RMSE took its maximal value of 3.6 mm in the out-of-plane direction. This indicates that the present method has potential for clinical application.

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The wrist is a complex joint, consisting of the eight small carpal bones that articulate with each other, the metacarpals distally, and the radius, ulna, and triangular fibrocartilage complex proximally. The wrist joint carries out complicated motions that combine palmar/dorsal flexion with radio/ulnar deviation. Knowledge of in vivo joint mechanics is important for understanding pathological mechanisms and the treatment of various joint problems. To examine wrist joint contact mechanisms, in vitro cadaveric studies have been performed using pressure-sensitive film. Investigations on in vivo joint contact mechanisms for wrist motion have rarely been reported. The aim of this study is to investigate in vivo wrist joint contact mechanisms during palmar/dorsal flexion by magnetic resonance imaging (MRI). Magnetic Resonance scanning was performed on the left wrist of twelve participants using a 1.5T-MRI system (Achieva, Philips Medical Systems, Best, Netherlands). The wrist joint was scanned at 5 positions (palmar flexion, -30 degree; neutral, 0 degree; and dorsal flexion, 30, 60 and 90 degrees). Quantitative analysis of wrist joint contact mechanisms was performed for 12 normal radioscaphoid and radiolunate joints. The in-plane motions of the scaphoid and lunate were measured. The contact area at the radioscaphoid joint was significantly greater than that at the radiolunate joint in all wrist positions. The contact area increased with increasing wrist angle, and the contact distributions indicated by 3-D models of the scaphoid and lunate were moved during palmar/dorsal flexion. Contributions of the scaphoid and lunate to in-plane motion at 60 degrees of dorsal flexion were 74% and 52%, respectively.

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