An optimization of the fluctuating punted kick is carried out using a genetic algorithm. It was assumed that there are five objective functions and nine control variables. The nine control variables, which are under the control of the kicker, determine the launch conditions. Since the control variables are too many to enable the optimal values to be determined manually, the optimization study is clearly necessary in order to find the optimal punted kick. Carrying out multi-objective optimization, the trade-offs between the objective functions and the control variables could be visualized using Self-Organizing Maps. It was found that the higher the spin rate at launch the greater the number of fluctuations; however, the hang time becomes shorter. Moreover, it was visualized how the control variables affected the objective functions by bubble charts.

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The purpose of this research is to estimate the angular velocity and direction of the rotational axis of the flying disc by inertia sensors. A subject performed throwing by using the flying disc attached the accelerometer. The closed up release and catching point images were acquired using the high speed cameras. The angular velocity was estimated from the centrifugal and angular acceleration. And rotational axis was estimated using gyroscope and accelerometer Estimated angular velocity and rotational axis were compared to the calculated angular velocity by the cameras.

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Aerodynamic characteristics of badminton shuttlecocks were investigated in a vertical wind tunnel. The drag coefficients were roughly 0.8 in the free flight condition having a self-rotation, whose spin rate amounted to roughly 0.25. On the other hands, in the condition of no rotation, which have been artificially realized, the drag coefficients were of the order of roughly unity. The results suggest a great effect of the self-rotation on shuttlecock performances. Observations by tufts and smokes made clear flow patterns around the shuttlecocks and the differences in the flow fields between both conditions with and without self-rotation.

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A shuttlecock which has an open conical shape is a high-drag projectile used in the sport of badminton, and the shape of the shuttlecock makes it extremely aerodynamically stable. In the present study, in order to understand the aerodynamic characteristics of a shuttlecock with rotation about shuttlecock's major axis, measurements of drag coefficient and the flow visualization around a shuttlecock were carried out in a wind tunnel. There was no significant difference in drag coefficients between the shuttlecocks with and without rotation when the shuttlecocks had reached quasi-steady state rotation. It was concluded that the drag force of shuttlecocks was not affected by the rotation rate and primarily related to the flow passing through the gap in the shuttlecock skirt.

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As you know, badminton is a well-known sport that young and old can play. The reason why everyone can enjoy is in strong deceleration of the shuttlecock, however, its aerodynamic characteristics have not been elucidated well. In the present work, using a low speed wind tunnel, effects of the flow passing through the slot located at leg part of the feather on the aerodynamic characteristics are demonstrated. Aerodynamic force and moment acting on the shuttlecock and flow field structure in the shuttlecock are measured in angle of attack rage from -10 to +10 degrees. The result shows: 1) The flow over the base surface separate at the shoulder of the base part, and formed a short bubble above the filled slot, and 2) As for normal configuration, dead water region is formed just behind the base part by the through flow from the slot#1. Pressure of this region is very low, and lead to pressure-drag increase.

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In this paper, we present molecular dynamics study of the fast proton transport in water confined between hydroxylated silica surfaces. Empirical valence bond (EVB) method was introduced to our MD simulation system for reproducing Grotthuss mechanism (proton hopping). We evaluated the enhancement of Grotthuss mechanism by counting the number of hopping events in confined and bulk water. The number in confined water increases by 4-6 times compared to bulk value, suggesting the enhancement of proton transport. Furthermore, the activation energy of Grotthuss mechanism was calculated from Arrhenius plot for the number of hopping events. As a result, the activation energy decreases from 4.5 kcal/mol in bulk water to 3.4 kcal/mol in confined water, which leads to the fast proton motion.

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In this study, the property of proton transfer in Nafion membrane was analyzed by molecular dynamics (MD) simulation including both Vehicle and Grotthus mechanism. To treat Grotthus mechanism, Empirical Valence Bond (EVB) method was introduced to MD simulation. The potential energy barrier of proton hopping obtained by EVB method was adjusted to the computational result of Density Functional Theory (DFT). After adjusting EVB potential, it is confirmed that protons hop along the hydrogen bond network consecutively. The parameter for the simulation of Nafion membrane was water contents λ, which is defined as the ratio of water molecules and hydronium ions to sulfo groups, SO_3^-, obtained by λ=N_<H2O,H3O+>/N_<SO3->. The changes of transferring properties and structure of molecules with the changes of λ were analyzed by Mean Square Displacement and Radial Distribution Function, respectively.

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The mechanism of oxygen permeation through an ionomer of polymer electrolyte membrane fuel cell (PEFC) was not analyzed in detail and it is too difficult to research by experiment. Moreover molecular dynamics simulation of the structure of catalyst layer and oxygen permeability has not yet reserched. We made the system including nafion, water, oxonium ion, nanoparticle platinum on a carbon layer by using molecular dynamics study, and researched about the structure of ionomer and the permeability of the oxygen molecule.

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DNA has several characteristics such as complementation, self-replicating function, and self-assembly network formation. They are expected to be applied to development of bio-nano technologies. In addition, phosphoric groups in main chains of DNA have negative charges in aqueous solutions. In this study, self-assembled structures of poly(dA)-poly(dT) DNA on highly oriented pyrolytic graphite (HOPG) is investigated. It is not easy to fabricate self-assembled DNA networks on HOPG due to the negatively charged surfaces. We try to artificially control the behavior of DNA in the aqueous solution by applying electric voltages. Using an in-house experimental apparatus and an atomic force microscope (AFM), self-assembled networks are successfully observed on the HOPG surfaces. The concentration of the aqueous solution is set to 0.5 μM. Consequently, based on the Fourier analyses, it is found that peculiar structures of DNAs, e.g., hexagonal textures, are formed on the HOPG surfaces.

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Because of its large specific surface areas due to its nanoscale structure, film made up with carbon nanotubes (CNTs) is an expected material for enhancing heat exchange. The specific behavior of gas molecules inside the film, however, has not been clarified yet. In this study, we analyzed the behavior of gas molecules inside the film numerically. The film was modeled by piling up cylinders representing CNTs, and different scattering models were used to investigate the diffusive movement of gas molecules. We calculated the scattering angle distributions and intrusion depth of gas molecules. We confirmed that although energy exchange of each collision between single CNT and a gas molecule is small, randomly oriented structure of CNT film induced diffusive movement of gas molecules, which leads to high accommodation between the film and gas molecules.

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The scattering process of gas molecules on vertically aligned single-walled carbon nanotubes (VA-SWNTs) was evaluated by molecular beam technique. To investigate interactions between VA-SWNT films themselves and helium gas molecules without the presence of substrates, free-standing films were used. The scattered molecules are divided into three components: reflected molecules, diffusively transmitted molecules, and directly transmitted molecules without interaction with SWNTs. Even with the thin film, most incident molecules were reflected from the films. This result suggests that most molecules well interact with the randomly oriented layer at the topmost of the films. High accommodation coefficients for helium in spite of its mass mismatching to surface atoms, demonstrates that VA-SWNTs films are useful as a surface modification to enhance energy accommodation.

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In this research, we reported the dependence of pore size on the characteristics of transport phenomena of confined water in a nano slit pore by molecular dynamics (MD) simulation. The two surfaces were made of graphite, whose distance was set at 15 and 30 Å. The interaction potential between water and carbon was Lennard-Jones potential, and that between water molecules was SPC/E. The water formed a film in each system. The film moved when pressure gradient parallel to the walls was given to water molecules in the pore. From the results, we examined dependence of the velocity of water in the slit pores on pore width.

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A bubble nucleation-growth process was investigated in a decompressed Lennard-Jones fluid using an NVT ensemble molecular dynamics simulation. As was reported in an NVE ensemble simulation, a competitive growth similar to Ostwald ripening was also observed in this simulation. On the other hand, more bubble nuclei were formed than those in the NVE ensemble and the growing/shrinking speed of each bubble nucleus became slower due to the temperature control. In this paper, the growth exponent for the mean radius of bubble nuclei was also evaluated, and it was confirmed that the value of the exponent became smaller than that in the NVE ensemble, at least in the present time scale.

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In this paper, we clarified the limit of classical method on the molecular simulation of cryogenic hydrogen. We applied three empirical potential models and one ab initio potential which was derived by Molecular Orbital (MO) calculation. We performed NVE constant Molecular Dynamics (MD) simulation across a wide density-temperature condition to obtain Equation Of State (EOS). Simulation results were compared with NIST data using the principle of corresponding states. As a result, it was confirmed that the effect of intermolecular interaction on the principle of corresponding states is small and cannot reproduce NIST data at the high density region. This distinction is considered to arise from the quantum effect of actual liquid hydrogen.

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Fine particle size measurement technique with laser interference fringes is proposed as one of the in-line measurement technique to the diameter of several hundred nano meter particles. The objective of this study is to examine the principle of this measurement technique with laser interference fringes. First, we visualize the flow structure in the flow cell with Particle Image Velocimetry (PIV). Flow structure in the flow cell is appeared stable. Second, we visualize the laser interference fringe images with high-speed video camera. And we identify the fringe images moving through the test cell. Finally, we measure the time variation of the intensity of the laser interference fringes by using two photodiodes. It is confirmed that the voltage signal depends on fine particle size. Also, the voltage signal depends on flow rate.

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Nakamori et al. found experimentally that the friction between a partly polished diamond coating and a metal surface was drastically reduced to zero as relative speed increased to a few m/s. [Diamond Relat. Mater., 14, (2005), 2122]. It seems that diamond coating took off the counter surface because sliding was noiseless in their experiment. In the previous work, we successfully reproduced lift force large enough to suspend the slider used in the experiment and found that this effect became notable only for micro-/nanoscale gas flow [IFS-Tsinghua University Joint Workshop 2009, Proceedings of 6th International Conference on Flow Dynamics, 584 (2009)]. In the present paper, we investigate the effect of configuration of micro-/nanoscale structure on sliding surface on molecular gas-film lubrication. Since micro-/nanoscale gas flows between two sliding surface cannot be treated as a continuum, we use the direct simulation Monte Carlo (DSMC) method.

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We found that micro-bubbles were generated from the orifice located at the oscillating end of hollow ultrasonic horn. Consecutive images obtained using a high-speed video camera and high-resolution snapshots using CCD camera with a microscope reveals that the generation of microbubble causes by the primary break-up of the gas-liquid interface near the horn end and the secondary break-up of released bubbles. We also investigated the dissolved oxygen concentration in water with bubbles generated by this generator. These results show microbubbles under 50 μm in diameter are generated only when an oscillation displacement of the horn end is over 49.6 μm (peak-to-peak).

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To clear the generation processes of the micro-bubbles in swirling flow-type micro-bubble-generators, we study the behavior of the air column, that rotates spirally about the axis of the micro-bubble-generator and the shift pattern from the air column to the micro-bubbles through the orifice plate for two types of micro-bubble-generators, by means of a high speed video camera with 250,000fps in framing rate. It is found that the break-down of the air column takes place around the orifice plate and the corresponding generation of the micro-bubbles.

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Microbubbles are expected to be applied in various fields such as engineering and medical fields. Thus, microbubble generation techniques with high efficiency are required. In the present study, we pay attention to the microbubble generator using a venturi tube (converging-diverging nozzle). This generator has a simple structure and a performance to generate bubbles of several-hundred-micrometer diameter at high void fraction. However, there are several unsolved parts about the bubble miniaturization mechanism. In order to clarify the mechanism of bubble breakup phenomena, we observe bubble fission behavior in a venturi tube in detail. Compared with the pressure distribution in venturi tube, it is suggested that rapid pressure recovery affects bubble collapse.

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The characteristics of functionalized microbubble jet with encapsulated activated air generated by DBD and UV irradiation were experimentally clarified for high performance liquid decomposition. The bleaching performance of methylene blue solution is enhanced by UV irradiation on microbubble jet with activated air for any solution pH. The effect of UV irradiation on bleaching is enhanced the most for neutral solution by production of radicals through photochemical reaction.

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The cleaning technique with low environmental load is required in industrial field. The present study is proposes a water-jet containing microbubbles type cleaning technique. Microbubble with diameter of about 100μm is generated through Venturi tube. Behavior in the tube is observed with high-speed camera. Pressure on the simulated cleaning surface is measured with a diaphragm pressure gauge. Pressure fluctuation with spike-like shape is appeared under the condition of bubbly flow. It is suggested that peak pressure generate when bubbles shrink rapidly. Average pressure, standard deviation of it, peak pressure decrease with distance front the tube.

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Collapsing bubble near wall boundary is numerically analyzed to clarify the mechanism of cavitation bubble collapse and develop numerical prediction method of cavitation erosion. 2D axisymmetric and 3D plane-symmetric calculations using a locally homogeneous model of gas-liquid two-phase medium are performed until the second bubble collapse. It is confirmed that microjet generation, propagation of induced pressure wave and collapse of torus bubble can be realized and that the second collapse is responsible for the intensity of cavitation erosion. It is also found that the collapse of slightly asymmetric bubble from spherical bubble causes the different distribution of maximum impact pressure.

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Nonlinear propagation of pressure waves in an initially quiescent liquid containing non-uniformly distributed spherical microbubbles is theoretically studied on the basis of the method of multiple scales. We focus on almost unidirectional waves propagating mainly in one direction with a weak diffraction or weak focusing to the transverse direction (like a ultrasound beam). Based on a methodology recently proposed by the authors, the KZK type equation, in which the dispersion and the non-uniformity of number density of bubbles are considered, is derived from the basic equations of bubbly flows.

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Understanding the interaction of a bubble with biotissue is important in order to clarify the mechanisms of tissue damage, such as vessel rupture, by acoustically excited bubbles. In the present work, the three-dimensional boundary element method was improved to simulate the collapse and rebound of a bubble in an elastic tube. The elastic wall was modeled with mass-spring systems. The three-dimensional deformation of the bubble, the deformation of the tube are taken into account in the simulation. The results show that the bubble on the axis of symmetry of the tube collapses following surface instability in the radial direction of the tube. On the other hand, when a bubble grows and collapses between the side wall and the axis, it translates toward the tube wall and the liquid jet occurs toward the wall in the collapsing phase.

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Cryogenic rocket propellants are easily densified by subcooling. However, cavitation in densified propellants can vary greatly from that in normal propellants because of the strong dependence of thermophysical properties on the fluid temperature, which can cause various problems in the propellant supply system of a rocket. Although many researches on the development of densification systems of rocket propellants have been carried out, characteristics on cavitation in densified rocket propellants have not yet been clarified. An experimental investigation of cavitating flows at an orifice nozzle was carried out in order to clarify the characteristics of cavitation in subcooled liquid oxygen. Comparison between influences of an orifice diameter ant a pressurized gas based on the thermodynamic parameter Σ^*, showed that the B-factor (dimensionless temperature depression) in the downstream of the orifice depends strongly on the pressurized gas (O_2, N_2 and He).

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There are many observations of cavitating flow using a high-speed video camera. They give us instantaneous and spatial images of cavitation clouds and surrounding small bubble behavior. In this study, we show some cavitation clouds behaviors using a high-speed video camera with an image analysis in order to estimate the behavior quantitatively. Especially, We show good advantages of frame difference method to analyze the behavior related to cavitating flow with small bubbles: e.g. growing and collapsing behavior of cavitation clouds and pressure wave propagation.

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To clear the time-dependent feature of the cavity in a submerged water jet, we study the high-speed behavior of the cavity development process from the free surface to the surface of the test specimen, by means of a high-speed video camera and the VOF-simulation method. It is found that after the water jet impacts on the free surface, the submerged jet forms a cavity, whose configuration is similar to a line like a string of beads within a limited time, and the time series of the cavity aspect correspond to those simulated by VOF method.

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In the use of hydrogen energy, the hydrogen embrittlement should be investigated, and it is necessary to improve reliability and safety of machine components which are used in hydrogen environment. The hydrogen sensitivity of material depends on material structure, defect, and stress distribution. There is a possibility that the hydrogen invasion into material and the fatigue crack propagation with hydrogen embrittlement can be suppressed by introducing compressive residual stress using surface modification such as cavitation peening. In this study, the specimens made of austenite stainless steel JIS SUS316L with precrack were charged by a cathodic hydrogen charging method, and the fatigue test was conducted by a plate bending fatigue test.

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Cavitation is well known as evil phenomenon which causes severe erosion in hydraulic machinery such as pumps, valves and propellers because of impacts produced at cavitation bubbles collapse. However, a cavitating jet which is a submerged high-speed water jet with cavitation is used for surface modification such as introduction of compressive residual stress and improvement of fatigue strength in the same way of shot peening. In order to enhance ability of cavitating jet which depend on nozzle throat diameter and injection pressure, an erosion test for aluminum and a measurement of compressive residual sterss of duralumin induced by cavitation peening were carried out.

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Two-stage cavitation erosion tests were performed using carbon steel S15C with a cavitating jet apparatus in seawater and tap water. The mass loss of carbon steel S15C by cavitation erosion is reduced remarkably when the test solution is changed to tap water from seawater. However, the mass loss rate that occurs when the experimental environment is changed to seawater from tap water is markedly higher because of corrosive action and mechanical disruption, and their synergistic effects. Changes in the environment demand consideration of the fluid mechanics because mass loss increases remarkably when the environment is changed repeatedly to seawater from tap water.

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High-speed video observations of cavitating jets issuing from sheathed nozzles at the injection pressure of 5 MPa and the cavitation number of 0.03 are carried out to clarify the behavior of cavitating jet. Two types of nozzle A4 and A4-R are used in the experiments. Water jet into air issued from the nozzle A4 appears to be compact one, but that issued from nozzle A4-R disintegrates at relatively short standoff distance and disperses downstream. Image analyses of the videos are conducted and the relation between cavitation clouds discharged from the sheath outlet and the flow structure inside the sheath is investigated.

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In order to use hot spot at cavitation bubble collapse for chemical reaction, luminescence at the collapse was carried out using a chemical luminescence analyzer. Hydrodynamic cavitation produced by injecting a high-speed water jet into a water filled chamber with cavitation bubble, i.e., a cavitating jet, was investigated. In the present paper, in order to find a suitable nozzle, intensity of luminescence produced by the cavitating jet at various nozzles was evaluated changing with injection pressure. The ultrasonic noise was also measured to evaluate aggressivity of the cavitating jet. The spectrum of the luminescence was evaluated to make clear mechanism of the luminescence. It was revealed that the spectrum of the luminescence induced by the cavitating jet was related to hydroxyl radical.

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With the aim of extermination of the zooplankton which is harmful for the environment and aquaculture in some cases by hydrodynamic cavitation using an enlarged pipe, treatment efficiency was enhanced by optimizing the diameter and length of the narrow area of the enlarged pipe. In addition, effect of the downstream pressure of narrow area of the enlarged pipe was measured. From the treatment of artemia and copepod, which were a kind of zooplankton, by hydrodynamic cavitation using optimized enlarged pipe, it was shown that the zooplankton was successfully exterminated using the hydrodynamic cavitation with an enlarged pipe, and the downstream pressure of narrow area of the enlarged pipe could be enhanced the treatment efficiency.

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The cavitation is used for the sewage treatment and the water quality improvement, etc. It is a research in the present study to develop the pump that doesn't need the cavitation generation device. The number of the impeller blade is 4. The intensity of cavitation was measured by the acceleration on the pump casing and the occurrence region of cavitation was observed by the photographs. The width of the casing was fixed 10mm in this case, and it experimented on the blade width by 4.5mm, 6.5mm, and 8.5mm.

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This paper proposes a novel pumping method using ultrasound induced pressure differences and cavitations. An ultrasonic vibrating surface is fabricated at the bottom of a water tank. Standing waves are formed between the vibrating surface and the water surface. A vertical rising pipe of a small inner diameter of typically 0.3mm is inserted in the water in a typical depth of 1/4 to 1/2 wavelengths. Increasing the power of the ultrasound, steady cavitation clouds start forming around the pipe inlet, which suppresses the negative pressure in the vibrating cycle and results in continuous pumping of water. The pumping mechanisms are revealed and the pumping capability as well as characteristics is clarified. A pumping pressure of over 20kPa can easily be achieved by the proposed pumping method.

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We have conducted three-dimensional, time-dependent numerical simulations of arc plasma under an externally applied magnetic field in a cylindrical-shaped chamber filled with SF_6 gas to understand magnetohydrodynamic behavior of arc column. The simulation results indicate that the arc column with the externally applied magnetic field is rotated by Lorentz force, and the arc column has a swirling structure. Arc voltage is increased by applying a magnetic field.

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Spectroscopic measurement using light-receiving optical fiber with relatively high spatial resolution was carried out to determine the excitation temperature near plasma jet fringe under strong magnetic field. Although the spatial resolution was improved by using a single fiber, measured emission intensity became weak due to narrow collection area. Some proper combinations of spectral lines were observed by the emission measurement for the present study. Therefore, it is possible to determine the excitation temperature by selecting an appropriate wavelength region that has spectral lines from the upper and lower excited levels around nearer region of the jet fringe.

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The effect of sinusoidal central gas injection on the in-flight alumina spheroidization process was experimentally clarified by using DC-RF hybrid plasma flow system under a small input power. Spheroidization ratio was evaluated with correlating to frequency and amplitude of sinusoidal central gas injection, DC arc voltage, and also particle size distribution. Spheroidization ratio improves through active mixing of DC-RF hybrid plasma flow with powder. The maximum spheroidization ratio of 99 % for powder collected at z = 120 mm was obtained at f_c = 2 Hz with amplitude of ± 20 %.

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The innovative technology is proposed for micro particle mixing and transportation in a tube by electrostatic force and by induced flow with dielectric barrier discharge. The tube, so called DBD plasma tube, is composed of a pair of spiral electrodes both inside and outside of the tube for the generation of DBD plasma on the inner surface of a tube. The fundamental characteristics of DBD plasma tube such as discharge characteristics, induced flow velocity and ozone concentration were clarified experimentally. Furthermore, three dimensional potential distribution inside the tube was shown by computational simulation.

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This paper describes the water entry phenomena created by the impact of solid-liquid compound projectile. The spherical NdFeB permanent magnet was used as solid, and kerosene-based magnetic fluid was used as liquid in the experiment. The cavity of air in water was observed with high-speed video camera system. The effect of magnetic fluid adsorbed to the spherical magnet was clarified. The impact of the magnetic fluid coated sphere on the free surface of water readily causes the formation of subsurface cavity. The effect of the alternating magnetic fields on the cavity was also revealed.

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Effect of a uniform magnetic field on heat transfer in rectangular duct flow of a magnetic fluid was investigated experimentally. Experiment was performed with changing flow rate and magnetic field intensity. Magnetic field can be varied from 0 mT to 500 mT. The magnetic fluid used in this experiment is water-based magnetic fluid. Magnetic fluid in the rectangular duct is heated with uniform heat flux. 820, 1630 and 2450 for Reynolds number based on the hydraulic diameter was chosen. As a result of this experiment, in laminar flow, when the magnetic field is applied to magnetic fluid, heat transfer coefficient drastically increases locally in the region where magnetic field exists. This heat transfer coefficient becomes large with increasing magnetic field intensity and this increase of heat transfer coefficient is saturated. About 30 % of maximum increasing rate of heat transfer was obtained in the laminar flow of the magnetic fluid with applying magnetic field.

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Cryogenic slush fluids such as slush nitrogen and slush hydrogen are two-phase single-component fluids containing solid particles in a liquid, which have higher density and refrigerant capacity than a shingle-phase liquid. Moreover, the pressure drop reduction effect was observed at the high Re number region in a pipe flow. Since previous numerical results of flow characteristics of slush nitrogen agreed well with our experimental results, the three-dimensional thermal non-equilibrium two-phase flow model of this study is modified to be able to include heat transfer characteristics of slush nitrogen. The numerical study is also applied to clarify flow and heat transfer characteristics of slush hydrogen, and the results are compared with those of slush nitrogen.

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Slush fluid is a two-phase (solid-liquid) single-component cryogenic fluid containing solid particles in a liquid. Its density and refrigerant capacity are greater than for liquid state fluid. In the present study, pressure drop and heat transfer characteristics of slush nitrogen flowing in a 10 mm inner diameter, horizontal heat transfer pipe were experimentally investigated with changes of mean velocity, solid fraction and heat flux. Flow patterns of slush nitrogen and the behavior of solid particles were also observed using a high-speed camera. It was found that both the pressure drop and local heat transfer coefficient of slush nitrogen are less than those of the subcooled liquid nitrogen.

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Large eddy simulation (LES) is conducted to reveal turbulent phenomena in a liquid metal MHD generator with a square duct to which a non-uniform magnetic field is applied. The applied magnetic field suppresses the turbulence even in the downstream without the magnetic field. In the downstream, the central velocity is decelerated, so that an M-shaped velocity profile is observed as well as turbulence structures like a Karman vortex. Two streamwise gradients of the applied magnetic field bring out the twin eddy currents. It is found that a subgrid model based on the turbulence structure gives an appropriate representation of the laminarization unlike Smagorinsky model.

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In this research, the transient response of induced shear stress and the related flow behavior of two types of the Electro-Rheological (ER) suspensions containing nano-sized or submicron-sized TiO2 particles dispersed in silicone oil have been investigated when it has been under the application of an electric field and shear using a parallel rotary disk rheometer. The effects of shearing time, electric field strength, and very narrow gap height between disk electrodes on the shear stress and the flow behavior are investigated. This study is very important for the downsizing of Micro-Fluid Power System (MFPS) using ER suspensions because nano- / submicron-particle ER suspensions are expected not to be stuffed in a micro-gap between electrodes.

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The ultra-high heat flux characteristics and rapid cooling effect of the micro-solid nitrogen (SN_2) spray flow through a two-fluid nozzle to the heated plate was numerically investigated and measured by a new type of integrated simulation technique. Furthermore, PIA mesurement has been applied to clarify the solid-particle diameter profiles of the micro-solid spray, and the wafer resist removal characteristics by thermo-mechanical effect was investigated. Based on the integrated numerical and experimental study, a new type of ultra-high heat flux cryogenic cooling system and the thermomechanical resist removal-cleaning system using cryogenic micro-solid spray was developed.

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