Swirl motions of a liquid partially filled in a cylindrical vessel occur under a certain gas injection condition through a J-shaped lance. The swirl motions are classified into two types depending mainly on the aspect ratio of the bath: shallow-water wave type and deep-water wave type swirl motions. The aspect ratio is defined as a ratio of the bath depth to the vessel diameter. Particular attention is paid to the latter swirl motion in this study because of its high mixing ability. Empirical equations are proposed for the amplitude of the swirl motion in the case that sedimentary particles are lifted up into the bath.

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To investigate the effect of surfactant additives on the pressure drop and the liquid holdup in vertical upward two-phase flow, experimental studies were conducted for two types of surfactants: one was n-hexadecyltrimethylammonium chloride mixed with a counter-ion sodium salicylate (CTAC) acted as a foaming agent and the other was sodium oleate (SO) acted as a non-foaming agent. The surface tension was reduced to 50% of water by the addition of each surfactant. The pressure drop reduction (PDR) was achieved up to 90% by the addition of CTAC at low liquid volumetric flux conditions. The addition of CTAC caused the reduction in liquid holdup in the range of the gas volumetric fluxes between 0.2 and 10 m/s. The PDR was mainly caused by the reduction in the gravitational pressure gradient due to the formation of the liquid phase containing fine bubbles. When SO was added, the PDR of 5-10% was obtained. The main cause of PDR was the reduction in the frictional pressure gradient.

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The effect of surfactant additives on the flow characteristics such as the gas-liquid interfacial structure, flow pattern transition and liquid lump velocity was investigated in the vertical upward gas-liquid two-phase flow. Experimental studies were conducted by using the surfactant CTAC acted as a DRA(Drag Reducing Agent). The effect of CTAC on flow pattern was confirmed for the slug and churn flows. The intermittence and local flow reversal of liquid film in both slug and churn flows were inhibited by fine bubbles formed in the liquid phase. The slug flow region for high liquid flow rate and low gas flow rate conditions was replaced by the bubble flow, and most of the churn flow regions were changed into the annular flow. The liquid flow structure was also affected by CTAC. β_W and β_B decreased for the condition of 0.2≤j_G≤10m/s. P_w decreased for the churn/annular flow region, which corresponded to the decrease in the frequency of interfacial waves and disappearance of flow reversal. The velocities for both liquid lump and liquid film increased for the annular flow, which was closely related to the increase in the frictional pressure gradient.

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An experimental study on the effects of water quality improvement using oxygenic micro bubbles aeration to deep layer in a reservoir was carried out for two systems using a micro bubble ejector. The first system sets the ejector near the benthic region of the reservoir, while the second one pumps water from the benthic region, inject micro bubbles near the water surface, and sends micro bubbles with water slowly in a larger pipe to the benthic region. As a result, improvement of dissolved oxygen concentration was recognized for both systems for the region between the injection level and the thermocline without the destruction of it. Moreover, from the view points of the electric conductivity and the oxidation reduction potential, water quality improvement was also confirmed. By comparison of the two systems, the second one got the better result for the improvement of dissolved oxygen concentration.

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Local burning velocities of flamelet in a burner-stabilized turbulent premixed propane-air flame in the reaction sheet regime are investigated by use of a four identical sensors electrostatic probe and a three-color six-beam laser-doppler velocimetry (LDV) that give components of the flame-front velocity and the gas velocity, respectively. With this technique, the three-dimensional local flame-front velocity vector can be measured by electrostatic probe, and simultaneously the three-dimensional local gas-velocity vector can be measured by the LDV systems. The local burning velocity vector can be obtained from the three-dimensional local flame-front velocity vector and the three-dimensional local gas-velocity vector.
Under the experimental conditions investigated, the average turbulent fluctuating velocity is the same order of magnitudes the laminar burning velocity of the planer, unstained, adiabatic laminar flame. The flamelet burning velocity found from nearly zero to several times the planer, unstrained, adiabatic laminar burning velocity. There are differences in results that depends on whether flamelets transverses the burnt-to-unburnt or unburnt-to-burnt direction are recorded for the first time. When the flame front passes in the unburnt-to-burnt direction, the velocity vectors of the flame-front movement are directed mainly toward the burner axis and upward, and the direction of burning velocity vector is same direction of flame front velocity vector. But when the flame front passes in the burnt-to-unburnt direction, the velocity vectors of the flame-front movement are directed mainly outward and downward, and the direction of burning velocity vector is opposite direction. When the flame front passes in the burnt-to-unburnt direction, unburnt mixture is below flame front, but when it passes in the unburnt-to-burnt direction, unburnt mixture is above flame front. Therefore the direction of burning velocity vector corresponds to the position of reactant from flame front.

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A new method of estimating gas and liquid flow rates is proposed for a gas-liquid two-phase flow system. The method involves measurement of pressure drops in horizontal and vertical flow channels, and calculation of flow rates by Lockhart-Martinelli correlation. The method does not require the insertion of any sensing devices into the flow channel and does not rely on any previously calibrated correlations. Experiments are performed in slug, froth and annular flow regimes for an air-water system, and the usefulness of the proposed method is examined. The results revealed that gas and liquid flow rates could be estimated with the accuracies of 45% for gas phase and 37% for liquid phase with respect to mean values.

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Health assessment of a structure is various. In the architecture and civil engineering, a natural frequency is calculated by conducting the frequency analysis of the response waveform of the structure. In the case of a digital image correlation method, if a picture and time are connected, the displacement response of the structure will be obtained. Hence, we considered the applicability to the vibration phenomenon. We performed displacement comparison with a finite element method, and then investigated the accuracy of the displacement response waveform. As a result, good evaluation was obtained within a maximum of 0.07 pixels and an average of 0.028 pixels. Furthermore, it succeeded in assessment of the natural frequency by the frequency analysis. The natural frequency which changes in the structure was also able to be presumed within the error of the maximum of 2.85 Hz. The health assessment of the structure is possible by using the digital image correlation method and frequency analysis.

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Particles are solids. However, they have fluidity. Therefore, we can replace the fluid of a oil damper with the particles. The damping force of this damper is produced by friction and collision of the particles. The damper does not use a fluid, so its structure is simple and durability is good. A number of factors have an effect on damping force of the damper. In this research, the damping force of the damper using glass beads is investigated experimentally under constant vibration conditions. It is shown that the damping force and absorption energy of the damper are affected by size and packing fraction of the particles, and frequency of vibration.

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Crack in structure can cause collapse of structure. So that preventive measure must be done to stop crack propagation. Stopping hole is one of the crack arrester which is a mechanism which stops crack propagation. Stopping hole can not stop high-speed propagating crack in all cases. So re-propagation condition of crack from stopping hole does not clear up. This study finds out re-propagation condition with high-speed crack propagation experiment. In the experiment, we observed fracture phenomenon at ultra high-speed using C.G.S.methods. We bring out influence between crack propagation and size of stopping hole, and behavior of stop and re-propagation of crack propagation.

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A MEMS scanner grating projector is capable of projecting a cosinusoidal graiting pattern by using a 1-D MEMS scanner and a line laser. This projector scans a laser to be capable of performing projection without focal depth. Further, this projector is capable of shifting a phase of a grating pattern and changing the pitch thereof. In this paper, a shape measurement system with a deep measuring range is developed by using this projector. By using the phase-shifting method and a phase unwrapping method using gratings with two different types of pitches, a measuring range is expanded. This phase unwrapping method is capable of measuring a height of a wide range at a resolution when the pitch of a grating is small. Further, this shape measurement system is applied to bin-picking to show its effectiveness.

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The VITA method is one of the stochastic methods to investigate the coherent motion and the bursting phenomena in the turbulent boundary layer. Some researchers pointed out that the results analyzed by the VITA method contain the invalid detection of the bursting events and the VITA method can hardly capture the dynamic structures in the turbulent boundary layer. However, the reason of the incorrect detection has not been discussed in detail. The present paper reveals the problems of the VITA method and improves the stochastic technique to capture the bursting phenomena accurately. The features of the present method are to compute the VITA quantities based on the coherent motion in the turbulent boundary layer. The analyzed result shows that the erroneous detection is removed and the bursting phenomena are captured appropriately. The present method can easily incorporate the VITA quantities to the quadrant analysis and the QV burst method is newly proposed. The present method can clearly capture the ensemble averaged waveform of the bursting phenomena rather than the Q burst method.

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In recent years, some kinds of haptic devices have been developed and evaluated its efficiency with clinical tests, for example, upper limb training for patients with spasticity after stroke. We have developed a rehabilitation system for upper limbs, “PLEMO-P3”. In this paper, we developed new sensing device for detecting abnormal symptoms of stroke. The purpose of this study is to build an appropriate evaluation system for stroke patients with information of abnormal symptoms. As a first step, we conducted reaching tests with this device. In this clinical evaluation, the subject is stroke patients and healthy subjects. By comparison with a patient movement and a normal movement, we recognized some differences of gripping forces, grip rotation angle and ground reaction forces among their movements. The effectiveness of the evaluation system of PLEMO-P3 was proven by the experiment.

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There are many patients of ataxia: paralysis caused by brain stroke or asynergia. Early detection of functional deterioration and sufficient rehabilitative training are necessary for those patients. The rehabilitation support systems for upper limbs using force display system are expected to quantify the effect of rehabilitative training, and can enhance the motivation of an operator. Especially, the application of a passive-type force display system is desirable for its high safety. However, there are some directions and positions for which it is difficult to display the force in a passive-type force display system using only passive elements. To solve this problem, a method for improvement of controllability using redundant brakes had been suggested. This method made it possible to display more various force power and directions. In this study, we have developed a rehabilitation system for upper limbs with redundant number of brakes: Redundant-PLEMO-1.

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In-plane biaxial testing produces a two-dimensional stress-state that can be used to characterize the mechanical behavior of rubber materials. A technique is proposed of calculating nominal stress and strain from the tensile load-displacement data measured in a biaxial testing. The technique is characterized by its simple concept and the evaluation formula with high accuracy. The validity of the technique is verified through the numerical and experimental investigations.

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Because Carbon Fiber Reinforced Plastic (CFRP) composite materials have exquisite mechanical properties, they become a substitute for aluminum alloys in various fields. However, they are fragile to external force from antiplane due to their strong anisotropic characteristics. To clarify the effect of inserted fiber direction on the fracture behavior of CFRPs, high-speed impact experiments under cryogenic temperature were conducted on this research. As a result, it was confirmed that variables such as temperature, impact velocity, and the fiber direction have influence on the fracture behavior of CFRPs.

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