The cantilever type rotating bending fatigue tests were conducted in order to investigate the effects of shot peening treatment on the fatigue property in the Ti-6A1-4V titanium alloy. Shot peening was performed with three types of fine zirconia shot grids. The fatigue lives of the shot peened specimen which fractured from inside the specimen with the fish eye on the fracture surface were longer lives than that of non-peened specimens which fractured from specimen surface. To discuss these fatigue properties, the fracture surfaces were observed and the peening effects such as surface roughness, hardness were examined. From the observation results of fish eye pattern on the fracture surface, it was clear that residual stress influences a fatigue property of Ti-6A1-4V greatly.

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This study examined the deformation behavior and fatigue crack initiation of a carbon-steel film under cyclic shear loading. As a result,two relations about fatigue behavior were found. Observation of Crystal direction, two relations about fatigue behavior were found. Observation shows that the slip occurred by shear surface outside. On the other hand,generation of the crack by shear surface inside.

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In this study, the effect of surface treatment on tensile property of jute monofilament was investigated. Jute monofilament was treated by two surface treatments; alkali treatment and silane treatment. Surface treatments were carried out in distilled water with l to 5% concentrations at room temperature for two hours. In case of alkali treatment, jute monofilament was washed with distilled water containing 1% acetic acid to neutralize the remaining NaOH molecules. Quasi-static tensile test of jute monofilament was carried out in 1[mm/min]. The Weibull distribution was used to examine dispersion of jute monofilament. As a result, tensile strength and Young's modulus of alkali treated jute monofilament were larger than those of virgin materials. Tensile strength of silane treated jute monofilament was larger than that of virgin. However, the Young's modulus of 5% silane solution treated jute monofilament decreased. Tensile property of alkali treated jute monofilament was affected by a crystal 0f the cellulose. Tensile property of silane treated jute monofilament was affected by the modification of fiber surface.

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In this paper, influence of kinking damage on the tensile strength of high-modulus type poly-p-phenylene benzobisoxazole (PBO) fiber was investigated in monofilament tests. Kinking damages was created on surface of virgin fiber by winding bundle fibers to steel rod. Diameter of steel rod was set to 5, 2.5, 1.25 and 0.65 mm. Average value of compressive strain on surface of fiber corresponding to the diameter of steel rods were -0.205, -0.419, -0.848 and -1.627%. Kinking damage density was defined to evaluate occurrence of kinking damage owing to bundle fiber was wound onto the steel rod. It was found that the tensile strength of fiber with kinking damage was well fitted the Weibull distribution function with 2 parameters. Kinking damage density increases with increasing compressive strain on surface of fiber. Tensile strength of fiber with kinking damage decreased with increasing kinking damage density.

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Dental resin composite is widely used in recent years because of its excellent aesthetic and operability. However, the fatigue strength of resin composite is not clear until now. Therefore, in this study we explored the improvement method in strength by means of filler hybrid using several types of fillers. Especially, we studied on how to improve the fatigue strength of resin composite by changing in filler means of content and, filler shape.

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The method of finite strain measurement based on the image analysis is suggested by using the Natural Strain theory. The effectiveness of this measurement method has been verified by comparing the strain measurement by the image analysis with the conventional measurement based on the displacement meter. However, the verification of strain measurement has been done under the uniform deformation field. Hence, the verification under the local deformation that arises after the uniform deformation has not been examined yet in those studies. Therefore, as the most fundamental case, the measurements under local deformation for uni-axial tension or simple shear were conducted in the previous report. As a result, it became clear that the measurements on upper position of the specimen differ from the measurements on middle position in case of uni-axial tension, but, in case of simple shear, these measurements were not so different from. In this paper, the progress of local deformation is examined by changing the loading history of these deformations. Especially, the local deformation that is generated under shear deformation after applying the tension is examined by changing the magnitude of the tension.

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In the previous report, using the Natural Strain theory, the shape of yield surface and the distribution of the strain hardening modulus h around the yield surface have been examined by conducting the proportional loading tests for tension and torsion after giving the pre-deformation of uni-axial tension to the test pieces. In this paper, the shape of the yield surface, which is obtained after giving the pre-deformation of large simple shear, is estimated by examining the strain hardening modulus h in various directions in the stress space. Especially, the development of anisotropy for the shape of the yield surface is examined by changing the direction of the pre-deformation of simple shear. Moreover, the yield surface estimated by investigating the strain hardening modulus h for various directions in the stress space is compared with the shape of yield surface obtained by the conventional proof stress.

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In this study, near-field Raman spectroscopy with high special resolution has been developed. This near-field Raman spectroscopy system consists of scanning near-field optical microscopy (SNOM) and polarized micro-Raman spectroscopy with oblique backscattering configuration. By using this system, near-field Raman spectrum of Si was evaluated. However, it was very difficult to detect Raman signal because near-field Raman scattering signal was very weak. To improve the signal, tip-enhanced system was added to developed system. Au coating apertureless SNOM probe has been developed by FIB machining. The curvature radius of this probe tip is less than 50nm. Polarized oblique incident light was irradiated to the probe tip and Raman scattering light was detected. As a result, enhancement of Raman scattering intensity was observed in the transition region from non-contact to contact of probe tip. Therefore, near-field Raman Spectrum of Si was able to be evaluated by near-field Raman spectroscopy with oblique backscattering configuration.

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One of the design methods for closing the end of a pressure cylinder is to screw down a screw plug on the threaded end of the cylinder. In this case, these is the problem of stress concentration in the threaded end of the pressure cylinder. To solve the problem, it is necessary to know accurately the load distribution on the threaded end of the cylinder. To find the load distribution on the threaded end of the pressure cylinder engaged with the screw plug, the following experiments are carried out. Applying the tensile load between the plug and the pressure cylinder and regarding the situation above as equivalent to the situation in which the internal pressure is applied, the load distribution is measured with the strain gauge. The influence of material of engaged thread on the load distribution on the threaded end of pressure cylinder is presented and an expansion of design manual is discussed.

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The ensuring safety for damages from high-speed shock phenomena has been required in air-conditioning machine field, and the establishment of evaluation techniques is expected. In this study, the fracture characteristic and deformation behavior of SPHE (Steel plate hot deep-drawn extra) steel cylinders was examined as a preliminary study. SPHE steel cylinders were expanded with high strain rate by PETN (Pentaerythritol tetranitrate) explosive. SPHE used for a typical refrigerant circuit component like a compressor has relatively higher ductility among carbon steels. The deformation of cylinders was observed by high speed camera and the fractures were evaluated from the fragments after high-speed shock test. Numerical analyses were also made to evaluate the high-speed shock deformation phenomena.

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This paper presents numerical solution for anisotropic tube subjected to shear forces in an axial direction. Generally, a mapping function is used for the analysis of the anisotropic body in two-dimensional problems. However, there is no mapping function which is transformed anisotropic tube to rig. So this problem is solved by the convergent calculation so called the constraint-releace technique. Moreover several example calculation are shown.

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In this study, we research the mechanical properties of Capsule-Chuck which is a product to hold and turn a roll's core. Capsule-Chuck holds roll's core by swelling urethane loading Air pressure. We want to research the performance characteristic of Capsule-Chuck. When the roll's core contacts fixed parts of the capsule by increasing of load, dust is generated and the rolls of products are damaged. For that reason, we have to know the load limits of Capsule-Chuck and research maximum load of Capsule-Chuck by using the new experimental device and try to develop experimental formulas by using Hertz contact theory. So we assay cross-section shape of the capsule to obtain its curvatures for Hertz contact theory.

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Capsule-Chuck is a support part used in order to grip the core of a continuation medium. In order to satisfy the needs to diversify, new product are expected. However, the deformation properties of Capsule-Chuck is not yet clarified. Creep deformation that is one of the characteristics of the Capsule-Chuck may affect to the winding of the roll. Therefore, to reveal the creep characteristics are required. In this study,using the formula Norton-Bailey the constitutive equation of creep, was carried out finite element analysis. And, were compared with experimental results to verify the validity of the model. As a result of comparing analysis and experiments, this model was found to be sufficient to represent the creep of the Capsule-Chuck.

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The Capsule-Chuck is well known chucking system to grip a roll in the Converting industries. However, mechanical properties of the Capsule-Chuck are not clarified yet. Mechanism of this chuck is expanded polyurethane elastomer which is called the Capsule under certain air pressure. In this research, new method to determine material contents both elastic deformation and inelastic deformation of the Capsule is proposed.

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The shot peening process is a widely used surface treatment method for improving fatigue strength and anti-wear characteristics. The surface of the material receives a so-called peening effect where strong local deformation forms a work-hardened layer or causes compressive residual stress. In the present study, the effect of peening time on surface hardness of spring steel was investigated. The optimum conditions were evaluated in an experiment using the conventional shot peening machine with shots of an average size. The projective method of the shot media was of the centrifugal peening type. The shot media of 1.0 mm diameter was high-carbon cast steel, and the workpiece used was the commercially spring steel JIS-SUP10. It was found from the present experiment that the optimum peening time for the conventional shot peening was about 90 s.

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In the shot peening process, metal foil can be bonded with the base metal by applying plastic deformation and the pressure. The formation of an Fe-Al intermetallic compound film on high-speed tool steel by shot peening and heat treatment was investigated. The effect of heating temperature on intermetallic formation of pure aluminum and base material bonded by shot peening was studied. In the experiment, a centrifugal-type peening machine with an electrical heater was employed. The shot peening process of high-speed tool steel with an aluminum sheet was carried out to evaluate the characteristics of the formed film. Heat treatment was performed at diffusion temperatures from 923 to 1573K in vacuum. When the temperature of the lined substrates was more than 1173K, the surface was covered with highly anticorrosive layers of Fe-rich intermetallics. It was confirmed that the present method could be used for the formation of functional films on high-speed tool steel.

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Paper acquires a certain profile when it is cut. This profile can be described as having a wear side and a burr side. The purpose of this work is to search for differences in the response of paper and PET subjected to a collision regarding which side is being collided. To investigate this difference, paper and PET specimens were slid through a 45 degree slope that was set to collide against a plastic counter plate. An acoustic emission (A.E.) sensor attached to the counter plate registered the vibration produced by the collision of the profile of the specimen. As a result, it was found that it is possible to find differences between the A.E. response of the wear side and burr side collision.

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In cold and snowy area, welded structures on the outdoors are exposed to combinational environment of the salt damage and the freezing damage, in which the corrosive solution containing CI" chlorine ions from the sea breeze and snow melting agents undergo freezing-thawing cycles during the winter. The cause of pitting corrosion phenomenon which occurs in the welded stainless steel under such a combinational environment has not yet been clarified. In the present study, it is investigated that the effect of corrosive factors on the progression of pitting corrosion in welded austenitic stainless steel under freezing and thawing corrosive environment. Austenitic stainless steel SUS 304 plates with bead-on-plate welding are used as specimens. The specimens are fully immersed in FeCl3 solution. The freezing-thawing environment is created by temperature cycling form 20 ℃ to -20 ℃. One cycle of freezing-thawing is 12 hours and 24 hours.

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Nonporous layer was fabricated on surface of closed-cell type aluminum foam (Shinko Wire Company, Ltd.: ALPORAS, relative density: 0.1, mean diameter of pore: φ4 mm) by friction stir incremental forming method. The nonporous layer with mean thickness of 240 μm was successfully fabricated under appropriate forming conditions. To examine the mechanical properties of the fabricated aluminum foam with nonporous layers, uniaxial compression test was carried out on a material testing machine at room temperature. The specific compressive stress (compressive stress/bulk density) of the fabricated aluminum foam with nonporous layers was enhanced.

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Friction stir incremental forming process for forming A5083 aluminum alloy sheets was calculated by finite element method. Conventional incremental forming process was also calculated and the both calculated results about distributions of temperature, plastic strain and deformation after springback were compared each other.

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An aluminum alloy, 5083-0, was subjected to friction stir processing (FSP) with the aim of improving its room-temperature mechanical properties and realizing superplasticity in the high temperature region; a 6 mm thick rolling sheet of the alloy was used in the experiments. Further, various FSP conditions were employed to achieve microstructure refinement of the alloy. It was confirmed from the experimental results that the average grain size in the FSP region, i.e., the stir zone (SZ), decreased with a decrease in the frictional heat generated during FSP. Moreover, it was observed that the room temperature mechanical properties of the alloy in the SZ satisfied the Hall-Petch relationship. Further, annealing tests were conducted to investigate the thermal stability of the alloy in the SZ. The microstructure of the alloy in the SZ was apparently stable at temperatures below 723 K. Therefore, it was expected that high-temperature tensile tests conducted at temperatures below 723 K would be suitable for realizing superplastic elongation in the alloy. The above-mentioned results are briefly discussed in this paper.

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The liquid phase diffusion bonding test of Ti-6A1-4V was performed using Ti-20Ni-20Cu-20Zr brazing alloy. The process temperature was 905, 935, 965 deg C. The hold time was 10, 60, 120 min. Metallograhic structures of bonding layer were evaluated, and needle-like structure layers were observed at all test conditions.

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In order to improve ductility of lead-free soldering of Sn-Cu, net shaped Sn-Cu was formed by sputtering technique newly proposed by the authors. Sn-Cu film was heated and change of the phase was measured using X-ray diffraction method. The result showed that Cu_6Sn5 which was not observed for no-heating specimen started precipitation by heating, and the amount of Cu_6Sn5 gradually increased with increasing heating temperature, and reached a constant value at a temperature about 600K. Scanning electron microscopy showed that Sn-Cu film started melting at a temperature around 65 OK. The result of bending test showed that strain at delamination of no-heated specimen exceeded 10%, and that of specimen heated at 620K and 773K exceeded 5%, which is larger than that reported for bulk Sn-Cu material.

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Aluminum alloy composites reinforced with short potassium titanate fibers were fabricated by squeeze casting, and the properties at high temperature and turning machinability of the composites were investigated. The composites reinforced with potassium titanate whisker and aluminum borate whisker were also fabricated to compare their properties with the short potassium titanate fiber reinforced composite. The reinforcements were randomly arranged in the alloy matrix, and no agglomeration of the fibers or porosity was observed. The proof strength of the composites were higher than that of the unreinforced alloy. Coefficient of thermal expansion of the composites was smaller than that of the unreinforced alloy. The cutting force was lowered by the reinforcement, and that of the potassium titanate fiber reinforced composite was lower than that of the whisker reinforced composites. The roughness of the machined surface was lowered by the reinforcement. This result and the in-situ observation of cutting process indicate that the reinforcements in the composite suppress the formation of the built-up edge. Continuous chips were formed after cutting the unreinforced alloy, while serrated chips were formed after cutting the composites. Tool wear after cutting has also been investigated.

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In order to obtain the composites with high electrical conductivity, the vapor grown carbon fiber (VGCF) dispersed aluminum (Al) composites was fabricated by rolling and annealing from the mixture powders of VGCF and Al. The electrical conductivity of the composites along rolling direction is higher double than the composites with homogeneous structure fabricated by sintering process, which is caused by the suitable orientation of VGCF.

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Adjustment microstructure by an annealing treatment and polymer alloy is a functionalization method of biodegradable plastic. In addition, the generalization of the biodegradable plastic, there is a need to evaluate the hydrolysis behavior and strength. Therefore, in this investigation, the effect of mechanical strength and hydrolytic behavior to functionalized biodegradable plastic were examined. In the experiment, poly lactic acid(PLA) was selected as the base material. Annealing treatment substrate were annealed at various times at 100℃ for PLA substrate. Polymer alloy material was prepared by mixing at various ratio of poly butylene succinate(PBS) and PLA. Tensile tests, impact tensile tests were conducted to evaluate the mechanical properties of each specimen. SEM and polarized light microscopy was used to observe the microstructure of the substrate. After hydrolysis, annealed substrate resulted reduction in tensile strength is small compared to the untreated. Elongation of the polymer alloy material improve with increasing content of PBS. Furthermore, impact strength was greatly improved at a ratio of 60:40 by weight. Than these results, the possibility of modifying the mechanical properties and resistance to hydrolysis has been suggested.

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When a biodegradation plastic is used as a substrate, ion beam irradiation produces thermal damage through a combination of low heat resistance and thermal shrinkage due to weak adhesion between the base material and the metal thin film. The formation of a reforming layer is expected to improve adhesion between biodegradable plastic and thin film. Reforming layer formed to deep range by He^+ ion beam irradiation. Or reforming layer formed to shallow range by Ar^+ ion beam irradiation. Energy to give the substrate surface by He+ is low, because forming density of reforming layer is lower than Ar^+. On the other hand, energy to give the substrate surface by Ar^+ is high, because degradation of the substrate surface falls for a short time. And, it is possible that while a think stable reforming layer is formed in a surface neighborhood. In this study, the reforming layer were formation by ion beam irradiation of different ion species on biodegradable plastic surface, the metal thin film adhesion was examined. Then, it was used that Argon and Helium as ion species and Titanium as metal species. The results of study clearly demonstrated that Ti thin film adhesion can be enhanced by the presence of a reforming layer. Furthermore, it was clearly that a Ti thin film adhesion excels under the terms of large-radius Argon gas ion.

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Refuse-derived fuel (RDF) produced by organic matter waste is expected. The problems of RDF include realization of a high heating value, removal of chlorine gas, reduction of the ash content, and suppression of the flammable gas by anaerobic fermentation. In this study, in order to reduce the ash content and realize a higher heating value, the addition of plastic waste rather than lime to RDF was investigated. Carbonization of RDF was carried out to determine its heating value and stability. The energy of fabrication process of carbonization RDF was evaluated. The composition of RDF was determined based on the composition of the municipal solid waste in Hachioji city, Tokyo. Gas components were measured for each RDF carbonization treatment. The heating value, ash content, and carbonization gas composition results were compared. Than these results, the heating value and ash content of the carbonized RDF were improved and reduced, respectively. The volume and weight of carbonized RDF of containing plastic were reduced by 1/3 and 1/4, respectively. The reduced volume and weight ensure stability and easier transportation.

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Carbon-based solid acid catalysts have shown great potential in a wide range of applications. Magnetic mesoporous carbon composite materials also have enormous potential especially in separation and adsorption technology. However, existing methods of synthesis of magnetic mesoporous carbon composites are complex multi-step procedures that are hard to control. A carbon-based solid acid catalyst has been successfully synthesised from amorphous carbon. However, existing techniques have been unable to produce a magnetically separable solid acid catalyst simply. Here we show that a magnetically separable mesoporous carbon-iron oxide nanoparticle composite with an amorphous structure can be readily synthesized. Further, a magnetically separable mesoporous carbon-based solid acid catalyst can be synthesized from this material by sulphonation, and this acid has a catalytic function. A magnetically separable catalyst can easily be recovered and reused, reducing the environmental impact of industrial processes.

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The discharge coefficients of throat tap nozzles of ASME PTC 6 with several tap diameters are experimentally investigated their behavior of the discharge coefficient for high Reynolds numbers from 1.8x10^5 to 1.4x10^7 using calibration facilities in NMIJ. Experimental results show that the discharge coefficients depend on the tap diameter normalized by the throat diameter and the deviation between the experimental results and the reference curve of PTC 6 is 0.75% at maximum.

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The objective of this research is to investigate the performance of drier with next generation engineering plastic pellet. This drier is made by Tokki Co.,Ltd. The previous drier was the cyclone type drier. The cyclone type drier is maintained the momentum balance of impeller regularly. These maintenances are very expensive and need long time. The first unit of engineering plastic drier which was more efficient than a cyclone type was developed. However, the first unit was a high price. We grasp performance of the first unit and aimed at the cost price reduction. As a result of grasped performance, we understand that we may change the blower motor from 3.7kW to 2.2kW, and it is succeeded by cost price reduction with maintaining performance.

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The objective of this research is to upgrade the performance of dehydrator for next generation engineering resin pellet. Perform visualization of three-phase flow part, and we went to check the status of transportation. To visualize, we have adopted the acrylic plate as the material of the duct. Subsequently, additional experiments to verify the levitation force of each high-density resin pellets, and we research on the impact of density and shape on the levitation force. From Experimental outcome that the levitation velocity of PET (of the most high-density resin pellets used in this experiment) is 10.3 [m / s] is we have confirmed. All four types of pellets used in this experiment can be transported, because slowest velocity is 12.5 [m / s] in Air current velocity out of nozzle. Finally, we were measured for each resin Water attachment rate of after passing through the dehydrator, and decided the optimum amount of water.

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For the prediction of heat transfer coupled with sloshing phenomena in the propellant tanks of launch vehicle, the pressure drop induced by heat transfer and the dynamic motion of cryogenic liquid in sub-scale vessels were experimentally observed. The correlation between the pressure drop and liquid motion was confirmed in the experiment. Results of the test suggests that pressure is sensitive when gaseous species are same as liquid. In addition, even if a gaseous temperature is different (about 3 OK), the amount of pressure drop does not change.

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Recently, it is required to reduce windage loss of rotors such as motors for cars as they are used at higher and higher speed and the windage loss becomes larger. At first, this paper shows that large diameter spiral grooves can reduce a pressure in the housing quickly and largely, and also shows that the gap between spiral grooves and rotor must be quite narrow such as less than 10 μm for the high-performance depressurization function. Next, this paper proposes "leaf spiral grooves pump (LSGP)" to keep the gap quite narrow even under the condition of severe vibration and large change of the temperature which often cause the unsteady gap. LSGP is formed by multi layered flexible leaves like a leaf seal. Three-dimensional numerical analysis shows that LSGP can reduce the pressure properly.

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The control parameters for a synthetic jet acting on a separated flow over hump are optimized by using multi objective optimization and effects of separation control are discussed. The following three parameters are used for operation of a synthetic jet: a synthetic jet position, a maximum velocity of jet and a synthetic jet frequency. A Direct Numerical Simulation (DNS) is performed by solving compressible, unsteady, laminar flows over a half cylindrical hump in two dimensions, and effectiveness of each operation of a synthetic jet is investigated. The optimization results show that periodic actuation improves aerodynamic coefficients. In particular, the performance of the synthetic jet placed around the top of the hump is better than other positions. A jet that is positioned at 94[deg.] and F^+ = 0.2 maximize the lift. On the other hand, a jet that is positioned at 104[deg.] and F^+ = 0.7 minimize the drag.

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We study the complex flow inside a model of a hard disk drive (HDD). The air flow in a HDD exhibits complex behavior due to the disk evolution and three-dimensional internal geometry. While the air flow is necessary for flying the magnetic head slightly above the disk, it may interact with the disk and a read-and-write assembly (RWA). The interaction induces forces to these parts, which may lead the head to the crash against the disk. We design a new HDD model to investigate the flow mechanism leading to the fatal crash. The model is equipped with a pair of rotating disks in a non-axisymmetric enclosure with an RWA. The feature of the new model is a large flow stagnation area, which has not been taken into account in the past but could play an important role. Based on the newly designed model, we built a scaled experimental apparatus, with which a series of flow visualization experiments is performed. Our investigation focuses on the interaction of the large vortex structures with the RWA and the role of the stagnation area to the whole flow. Refractive-index matching will be applied to the transparent flow apparatus so that the internal flow can be observed without the images being hindered nor distorted through the complex geometry.

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Aerodynamic characteristics have great influences on vehicle performance. In order to improve the aerodynamic characteristics, it is necessary to clarify structure of the flow about the body. The aim of this research is to analyze the influence of configurations of road vehicles on aerodynamic characteristics. As configuration parameters, the rear window angle and the side window angle are adopted, and totally 33 patterns of configurations changing from box type through fastback to notchback types are investigated by wind-tunnel experiments. As results, in the cases of side angles 0° and 15° , the drag was increased at rear angles between 25° and 30°, while in the case of side angle 30° this tendency was not detected. In the whole cases it was shown that the more the side windows is slanted, the less the drag is. The factor is that when the inclination of the side window becomes large the angle between the rear and side surfaces becomes obtuse, and the formation of longitudinal vortices is restrained. The flow visualization by tufts and the five-hole pitot tube detected the trailing vortices, and the factor was confirmed.

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Recently, many studies on flow characteristics around square cylinder have been discussed especially on the shape modification and corner cuttings. However, the effect of grooves to the aerodynamic characteristics of square cylinder is still unknown. Therefore, in this study the flow characteristics around square cylinder with various grooves shapes is investigated in detailed by drag coefficient measurement. The shapes of the grooves are rectangle and arc. The drag is measured by a wind tunnel experiment. As the result, the square cylinders with grooves have a lower drag coefficient compared to square cylinder without grooves. Furthermore, the different drag coefficient reduction rate was observed in different grooves shape. The square cylinder with the rectangle shape grooves has a bigger reduction rate compared to arc shape grooves.

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The effects of laminar boundary layer thickness and aspect ratio on the aerodynamics of a circular cylinder supported by two large end-walls were studied by measuring the surface pressures in detail. The relative boundary layer thickness δ/d was kept at 0.26 or 0.82, and the aspect ratio L/d was varied from 10 to 30. Consequentially, in the case of large δ/d, the base pressure coefficient and the drag coefficient vary greatly over the large spanwise range from the cylinder end. Then, the drag coefficient variation is closely connected with the relative boundary layer thickness.

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A behavior of arc under an obliquely imposed alternating magnetic field to the arc is theoretically investigated. It is known that the arc oscillates in a plane when the alternating magnetic field is imposed perpendicularly to the arc. In the present work, the governing equation for arc motion is obtained and solved. The numerical analysis results suggest that motion of the oscillating arc with obliquely imposed alternating magnetic field becomes three-dimensional pattern and there is a possibility for the arc to be unstable under some conditions. When the crossing angle for imposed alternating magnetic field to the arc larger than π/4 [rad], the trajectory of the plasma gas fraction is upturned. On the contrary, the crossing angle smaller than π/4 [rad], the trajectory of the plasma gas fraction is always downward and the arc has a root on the anode. Variations of the arc motion depend on the crossing angle for imposed alternating magnetic field to the arc.

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We have investigated aggregation phenomena in a suspension composed of rod-like hematite particles, which have a magnetic moment normal to the particle axis direction, by means of Brownian dynamics simulations. The present Brownian dynamics method takes into account the spin rotational Brownian motion about the particle axis in addition to the ordinary translational and rotational Brownian motion. We have investigated the influence of the magnetic particle-field and particle-particle interactions, the shear rate and the volumetric fraction of particles on particle aggregation phenomena. Snapshots of aggregate structures are used for qualitative discussion and the cluster size distribution, radial distribution function and orientational correlation functions of the direction of particle axis and the magnetic moment are focused on for quantitative discussion. The raft-like clusters are significantly formed at a magnetic particle-particle interaction much larger than that for a magnetic spherical particle suspension. An applied magnetic field enhances the formation of raft-like clusters.

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Thermal spray is one of the successful surface finishing methods that provides restoration or a new function on various mechanical components. In the thermal spray process solid particles are accelerated by a high temperature and high velocity gas stream. After impacting on the surface of the substrate, the particles are deformed into a coating. The particle velocity is often measured by Particle Image Velocimetry (PIV). However, the meaning of the velocity vectors, obtained by the PIV with thermal spray powder as seeding particle, is not clear since the solid powder has a wide diameter range. This paper shows the consideration on the PIV data, with thermal spray particle as seeding powder, based on gas-particle two-phase flow. Comparison of the PIV measurement result and the calculated result reveals that the velocity obtained by PIV is almost identical to that of the area-averaged diameter of the seeding thermal spray powder.

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The purpose of this study is to clarify the mutual relationship among the bubble motion, the surrounding liquid motion and the instantaneous mass transfer from the bubble to the liquid phase. For this specific purpose, the zigzag motion of the bubble were captured with high spatial resolution by a pair of high speed cameras, and instantaneous changes in volume and surface area of the bubble were obtained from the captured images by our originally developed method. The instantaneous mass transfer from the bubble to the surrounding liquid was enhanced at a section around the second inversion point. The enhancement in the mass transfer on the right side surface was dominant; hence the instantaneous mass transfer coefficient increased. In addition, in order to obtain the liquid motion induced by the bubble, Stereo-PIV measurement was conducted. As a result, the vortices were shed from the bubble rear in the sections. The vortices acted like transporting the liquid rich in dissolved CO_2 away from the bubble rear. The convective transportation was promoted; consequently the mass transfer was enhanced.

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Numerical simulation of supercritical water flow is presented. In the present scheme, the preconditioning method developed by the authors was coupled with Building-Cube Method (BCM). An Immersed Boundary (IB) method is applied to the wall boundary treatment and mathematical models of thermophysical properties for water programmed in the PROPATH is used for physical property estimation of fluids. In the paper, as a classical case, flow past a circular cylinder at low Reynolds number is calculated, assuming water at liquid and supercritical state as fluid medium. The behavior of supercritical water is identical to that of liquid water for conventional settings as expected, since its behavior totally depends on Reynolds number. By adopting a temperature difference, the behavior of supercritical water is significantly different from water liquid because of the sharp variation of physical properties.

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In this paper, numerical simulation for influenza infection was conducted using difference between air-flow course and virus-moving course. An alteration of radius of virus droplet changes sedimentation velocity. Then, the radius is affected by temperature and humidity around droplets. Flying virus drops may combine to other droplets. The repetition of the combination between droplets affects the sedimentation velocity of the droplet. Furthermore, using survival rate of influenza virus and human resistance, more realistic simulation is enabled. In this paper, the effectiveness of the method was shown carrying out infection simulation in an indoor environment.

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It was previously reported an input disturbance composed of some tens of frequencies can induce rapid development of homogeneous turbulence using a multi-fan type wind tunnel for which 99 small fans were driven to generate turbulence. Since this method includes many frequencies, little is known about requirements of frequencies. Here, we investigated streamwise development of homogeneous turbulence characteristics using input disturbances to which different pairs of frequencies contributed. First, disturbances composed of two selected frequencies, f_A = mf_0 and f_B = nf_0 were defined, and then two parameters, f_<mid> = (f_A + f_B)/2 and Δf = f_A - f_B, were introduced. It was found that integrated statistics such as intensity and scale were significantly dependent on fmid, but less dependent on Δf. Interestingly, however, in the case where m and n were coprime, more peaks emerged at frequencies af_A ± bf_B (a, b ; integers) in the downstream direction, but in the case where m and n were not coprime, regularly-spaced peaks sparsely appeared.

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The authors computed a supersonic flow created by a High Velocity Oxy-Fuel thermal spray gun by using the OpenFOAM and compared the numerical with result and mesurement. The spray gun is Praxair-Tafa JP-5000 with barrel length of 8inch. Combustion chamber pressure is set at 0.672 MPa. Fuel and oxidizer selected are kerosene(C_<10>H_<21>) and oxygen, respectively. Combustion gas temperature, chemical compositions are calculated by Chemical Equilibrium with Applications developed by NASA. The simulated result of the gas temperature well agrees with the mesurement. However, the simulated gas velocity deviated from the measured value.

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Interaction phenomena of compressible flow and solid object have been attracted interest from a point of view of numerical analysis and experimental investigation. In addition, in the medical field, the development of the technology of the extracorporeal shock wave lithotripsy which employs a high temperature and a high pressure condition caused by a shock wave is remarkable. To prevent the glass of house from being damaged by a sonic boom, to prevent the structure from being destructed by the explosion, and etc., the interaction problem between shock wave and the solid object has been studied. In this study the flow field, in which a shock wave issuing from a diaphragmless shock tube impacts on an elastic block made by acrylic or polycarbonate, is visualized experimentally using Schlieren method. The shock Mach number is about 1.37. As a result, a stress wave is induced by a collision of shock wave and it is found that the characteristics of the stress wave depend on the material and the strength of shock wave.

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In order to comprehend the interaction phenomena between plasma and shock wave, shock tube experiment and numerical analysis were conducted. From the Schrielen visualization result, the shock wave deformation as like branch like structure was observed. From the numerical simulation, it was clearly showed that the brunch liked deformation structure of the shock wave observed in the shock tube experiment has the three dimensional structure.

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In a petroleum, gas or chemical plant, a valve is installed in piping system to automatically regulate the gas pressure in the upstream chamber. The gas flows through the valve at a high speed, often as a supersonic flow, which causes oscillatory phenomena of flow. The flow directly impinges on the pipe and vibrates the pipe wall, which leads to a fatigue failure of pipe elements for a short time in the worst case. The damage of a joint, in particular, where the pipe meets a large-diameter pipe downstream of the valve, is responsible for one of the critical accidents. To clarify a mechanism of "flow-induced vibration" like this, a transonic flow was examined which is established in a pipe with enlargement of cross-sectional area immediately downstream of a convergent nozzle. The vibration of the pipe is measured using strain gauges and a noise emitted from the pipe end is also measured to understand the conditions in the pipe. As a result, some dominant frequencies were found from analyzing the pipe vibration and the sound pressure wave. As the supply pressure increases, these frequencies gradually rise and approach the natural frequencies of an acoustic field in the pipe within a certain supply pressure range. Furthermore, the measurements of pipe vibration and sound pressure agree well with each other.

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