One of the advantages of polymer quenching is that it has slower cooling characteristics than water quenching. On the other hand, in polymer quenching, unlike oil quenching and water quenching, cooling effect changes with an increase of the number of quenching times. When slow cooling performance in polymer quenching deteriorates, quenching cracks sometimes occur. One of the causes of quenching cracks is regarded as the stress that occurs due to quenching. Quenching stress is affected by a cooling rate. Therefore, in order to prevent the quenching crack in polymer quenching process, it is important to understand the relationship between the change of cooling performance with deterioration of polymer solution and the quenching stress. The change of slow cooling performance of polymer solution with the number of quenching times was investigated. The cooling performance was evaluated by heat transfer coefficient which was obtained from quenching experimentation. The slow cooling performance of deteriorated polymer solution decreases below the solution temperature of 350℃ comparing to the fresh polymer solution at the same polymer concentration. As a result of quenching stress analysis, it was found that the largest quenching stress was obtained in deteriorated polymer quenching.

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Spaghetti is as familiar a part of current Japanese food culture as udon or soba. Udon and soba are tasted in the throat during swallowing. However, hardness determines the spaghetti taste. This research was conducted to apply texture tests and moisture content measurements to dried spaghetti noodles and raw spaghetti that had been boiled. We administered a questionnaire related to hardness. Results of moisture content measurements show that raw spaghetti had higher water contents when boiled than dried spaghetti noodles did. Fracture test results show that raw spaghetti noodles have a lower elastic coefficient than dried spaghetti noodles. Significant preference results of a Japanese survey showed a tendency by which boiled spaghetti noodles are preferred when they have a low modulus of elasticity. From the boiling time and maximum value, the change in elastic modulus was confirmed by the relation between the elapsed time of the strain at break.

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a-BC:H films with different boron/carbon ratio were fabricated on TiNb substrates at room temperature by pulsed plasma CVD. The boron/carbon ratio in the films was varied from 0 to 0.4 by controlling the flow rate of B(CH_3)_3 in the reaction gas mixture with C_2H_2. a-BC:H films with 0.03 and 0.4 exhibit high hydrophilicity surface due to their high wettability and high surface energy. Platelet adhesion experiment in vitro was conducted in order to understand the effect of boron on the blood compatibility properties of a-BC:H films compared to TiNb substrate as well as conventional DLC. The results showed that DLC and a-BC:H films can prevent higher platelet adhesion on TiNb substrates. a-BC:H films with lower boron content (0.03 B/C ratio) lowest platelet adhesion and activation because few platelets are present. This result indicates that 0.03 is the optimum boron/carbon ratio for developing anti-thrombogenic surface. The synthesized a-BC:H films appear to be promising surface modification for blood-contacting devices.

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In this study, time dependent mechanical properties of Celish sheets which have the potential to be used as acoustic speaker diaphragms produced from cellulose nanofibers were investigated. Specimens of Celish sheets with/without halloysite were investigated by using ramp-hold tensile tests. The stress-time curves of ramp-hold tensile tests show that Celish sheets with/without halloysite are time dependent materials and Celish sheet with halloysite have lower elastic moduli and larger relaxation constants. The time dependent mechanical behavior of Celish sheet was described by using the linear viscoelastic constitutive model with one time constant and the averaged stress time curves used obtaining the optimized parameters of linear viscoelastic model.

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It has been reported that the mechanical properties of titanium matrix composites depended on titanium particle shape and size. In this study, three types of Ti-6Al-4V matrix powders were used: hydride-dehydride (HDH) powders with particle sizes of <45 μm and <25 μm and gas-atomized (GA) powder with a particle diameter of 45 μm. TiB_2 powder with an average particle size of 1.81 μm was used as a reinforcement. TiB-reinforced Ti-6Al-4V alloys were prepared by SPS. Mechanical properties of composites composed of powders with different particle shape and sizes were investigated. As a result, the mechanical properties of the composites with HDH powders depended on the particle size. The TiB whiskers were uniformly distributed in the composites with smaller Ti particle. In the composites with HDH or GA of particle size of 45 μm, their mechanical properties depended on the particle size. The tensile strength and Vickers microhardness of the composite with HDH powder were higher than those of the composite with GA powder. On the other hand, the tensile strengths of the GA composites with the GA powder exhibited higher values at a high volume fraction of TiB.

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In shot peening, 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. More recently, a new type of microshot has been developed to enhance the peening effect. In the present study, the effect of microshot peening on the surface characteristics and fatigue strength of spring steel was investigated. The workpiece was commercial spring steel SUP9. In the microshot peening process, the equipment was used an air-type machine. The microshots used were high-carbon cast steel and cemented carbide with an average diameter of 0.1mm. Air pressure was 0.6 MPa and peening time was in the range of 10-100s. Surface roughness and Vickers hardness for the peened workpiece were measured. The out-of-plane bending fatigue tests were also carried at a frequency of 200 rpm. As the peening time increased, surface roughness for the peened workpiece decreased. The use of microshot was the very effective means of reducing surface defect. The microshot peening process was very efficient in improving the fatigue life of spring steel, especially at a high number of cycles. It was found that the use of the hard microshot was found to cause a significantly enhanced peening effect for spring steel.

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Internal frictions (damping capacities or logarithmic decrements) of nickel-based superalloys were measured under various temperatures using the inverted torsion pendulum apparatus. This report presents logarithmic decrements of the polycrystalline Inconel 718 together with those of the single crystal alloy CMSX-4. The temperature dependence of the logarithmic decrements were investigated from room temperature to elevated temperatures (up to 948 K in Inconel 718 and 1223K in CMSX-4). At temperatures below 700 K, logarithmic decrements of Inconel 718 are smaller than those of CMSX-4. However, Inconel 718 is much larger in the logarithmic decrement than CMSX-4 at temperatures above 700-800K. Further, Inconel 718, at temperatures above approximately 600-700K, increases steeply in its logarithmic decrement with the temperature. On the other hand, the logarithmic decrements of CMSX-4 at temperatures less than approximately 1000K scarcely depend on the temperature and increase gradually with the temperature at higher temperatures. It seems that Inconel 718 has a peak in its damping capacity at approximately 920K.

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Effects of the reinforcement with pitch-based carbon fiber on the wear characteristic of aluminum alloy have been investigated. Wear tests were carried out under dry sliding conditions using pin-on-disk method. The composites were fabricated by squeeze casting. Wear loss of the aluminum alloy was greatly reduced by the fiber reinforcement. The friction coefficient during the wear test of the composite was stable during the wear test compare to that of the unreinforced aluminum alloy. Furthermore, the value of surface roughness after the wear test has become smaller by the reinforcement with carbon fiber. The value of the counterface disk specimen was also decreased by the reinforcement The worn surface of the steel counterface alloy was mostly covered with aluminum when using the unreinforced aluminum alloy. On the other hand, iron, carbon and only slight aluminum were detected on the worn surface of the counterface when combined with the composite. These results indicate that the carbon fiber acted as a solid lubricant on the worn surface.

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In recent years, the price of alloys, such as Ni and Mo rises, so that it is difficult to use the stainless steel containing these elements. Therefore, Ni was reduced and Mn and N were added to the conventional stainless steels alternatively. 'Lean grade or Low grade1 duplex stainless steels have attracted industrial interest for substituting higher alloyed grades with the applications where strength is more important than corrosion resistance. In this research, studies were aimed at evaluating the corrosivity of low Ni high Mn-high N, namely duplex stainless steels S32101 and S32304 comparing with the conventional austenitic stainless steel SUS304. Vickers hardness test, Electrochemical Potentiokinetic Reactivation ratio (EPR) measurement, and microstructural observation were carried out using the steels subjected to 748K embrittlement of 748K, sensitization of 973K and sigma phase embrittlement of 1073K. The experimental results obtained in this study lead to the following conclusion. (1) The results of hardness test of the both duplex stainless steels showed the sign of 748K embrittlement, but did not show the sign of sigma phase embrittlement. (2) The hardness of the both duplex stainless steels were rather higher than SUS304 steel. (3) There may exist a correlation to the reactivation rate and the weight decrease rate of these stainless steels under freezing and thawing corrosive environment.

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This study investigate that the influence of shape of WC on solid particle erosive wear of cast-in insertion cast irons. Shape and size of WC were φ5 × 50, φ8 × 50 and □ 8 × 50mm. The area raid of WC of test surface is 50% at maximum. The test specimens for erosive test were mechanically machined to be sized 50×50×14mm. Specimens were tested using a blast machine. A comparison of the base material and the cast-in insertion casting material. Erosion rate was decreased by insert casting the WC in all of the specimens. Also EDS surface analysis was performed detail in order to observe bonded surface of between WC and base metal of WC cast irons. All cylindrical shaped WC transverse-mounted specimen was observed reaction layer in bond surface. The hardness of reaction layer was higher as compared to that of base metal. On the other hand, square shaped WC transverse-mounted specimen, the void of about 50μm was observed in bond surface of between WC and base metal. Erosion rate of cylindrical shaped WC transverse-mounted decreased in relations to square shaped WC transverse-mounted. From these result, it's considered that it's important for superior erosive wear resistance to formation reaction layer.

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Fretting fatigue strength tests of aluminum alloy (JIS A7N01) specimens with surface treatments (fine particle peening, burnishing and solid lubricant film) were carried out using an electromagnetic fatigue testing machine. From the in-situ SEM observations of fretting fatigue process, the fretting fatigue crack nucleated earlier in the order of the fine particle peening, untreated, burnishing and solid lubricant film It was found that burnishing with smooth surface and high cornpressive residual stress effectively delayed the fretting fatigue crack nucleation and propagation It was also found that solid lubricant film with low frictional coefficient effectively delayed them.

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In this study, we focused on graphene reinforced Al-based nano composite bulk materials. In order to disperse graphene around Al powders with average diameter of Al about 100 nm, ultrasonic vibration method was applied with isopropyl alcohol as a solvent before sintering composite materials. The powder before press sintering was prepared to dry in a furnace at about 340 K for 40 minutes. The composite materials with uniform dispersion of graphene were fabricated by with piston-cylinder type press apparatus under the condition of the applied pressure of 3t and the temperature of 723 to 823 K for 4 h in Ar gas atmosphere. We investigated the optimal condition of the composite materials as changing dispersion time by ultrasonic vibration from 1 to 6 h. And we also investigated the optimal condition of the composite materials as changing composition rates from 0 to 3.0 wt%graphene. In our results, vickers hardness of the composite material at 1.0 wt%graphene, dispersion time of 2 h and sintering temperature of 823 K showed the maximum value of 323 Hv, and the density was 2.45 g/cm^3. So, the specific strength increased up to 414 kN・m/kg. It is about 1.4 times bigger than that of Al material. Therefore, graphene reinforced Al-based nano composite materials give us dreams of development for innovative materials.

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Titanium and its alloys have low density, high specific strength, high fatigue strength, and good corrosion resistance. However, today they are underutilized in industry due to their high cost and poor wear resistance. To further improve their properties, TiB- and TiC-reinforced Ti matrix composites (TiB/Ti and TiC/Ti) were produced by the spark plasma sintering (SPS) process. We focused on how the matrix powder morphology and size affected their properties. Hydride-dehydride (HDH) and gas-atomized (GA) pure Ti powders with different powder sizes were used as a matrix, and TiB2 or TiC powders were used as reinforcements. We investigated the microstructures, Vickers microhardness, the tensile properties, and the wear properties of the composites. The types of the matrix powder strongly affect TiB and TiC distributions in the composites. As a result, they occur a large difference in mechanical properties. The ultimate tensile strengths, the stiffnesses, and the Vickers microhardness of the composites containing smaller HDH powders are higher than those containing GA powders. For the wear resistance of composites are higher than pure Ti.

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Pure Aluminum has light weight, excellent formability and corrosion resistance. However, it is inferior strength to steel materiAl. Taking into consideration with residuAl stress which has effects on the materiAl properties, compressive residuAl stress is expected to improve strength. We evolve Al-based composite materiAl adding an iron-based shape memory Alloy (SMA) fiber. Fe-Mn-Si-Cr Alloy, as a type of iron-based SMA is less expensive, better processability than Ti-Ni SMA, and has similar mechanicAl properties to Ti-Ni SMA. Aluminum matrix composite reinforced by iron-based SMA fibers was fabricated by spark plasma sintering (SPS). At this method, sintering of hard-to-sinter materiAls, as Al and Ti, is easy. The pure Aluminum powder and Fe-Mn-Si-Cr Alloy fiber were sintered at 773K. As a result of the pull-out test, the interface between pure Aluminum and SMA fiber was stronger in the composite sintered at 70MPa than 30, 50 MPa. From the interface observation, it was cleared that thickness intermetAllic phase affects to interfaciAl strength. Furthermore the mechanicAl properties are improved to composite with compressive residuAl stress by recovery process of SMA.

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Vapor grown carbon nano fiber (VGCF) dispersed Aluminum (Al) composites was prepared by two method; one is obtained by sintering after rolling of the mixed powders of aluminum particles and VGCF, and another is by rolling after sintering of the mixed powders. Relative density, fiber direction and the shape of aluminum particles in composites was estimated, and the relationship between these properties and the thermal conductivity was considered. VGCFs in composites became to array along the rolling direction by rolling. Furthermore, the aspect ratio of Al particles in composites and the relative density increased by rolling. But the thermal conductivity of the composites was not improved because of the aggregation of VGCF and the reaction products of Al_4C_3.

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Effect of injection molding conditions on the tensile strength of short carbon fiber reinforced polyphnylene sulfide (PPS) plastic was investigated in order to apply the plastic to the structural members of automotive components. The length of the carbon fiber is 200μm. The volume fraction of the carbon fiber was 30%. Tensile test specimens were produced by injection molding with two different molding conditions. The tensile strength was changed depending on the molding conditions. Since the size and number of porosity are significantly different between two specimens, it was presumed that the salient factor determining tensile strength of the specimens was porosity. The point is that the results of the tensile test showed similar trend in terms of the effect of molding conditions to that obtained pressure test of the prototype components which were produced by different molding conditions. Although formation of porosity during injection molding is strongly influenced by the shape of the component, simple tensile specimen could be used to a certain extent to optimize molding conditions or understand strength properties of the real component.

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Recently, aluminium (Al) based composites containing each carbon fibers (CF), such as carbon nanotubes (CNT), and vapor-growth carbon fibers (VGCF), are actively developed. These fibers have high thermal conductivities and high strengths. And then Al/VGCF composites fabricated using spark plasma sintering are known to have a high thermal conductivity. The composites are anticipated using for the application of heat exchangers. In this paper, an Al/CF composite are fabricated using sintering process. The relationship between microstructures and mechanical properties are considered using the sintering composites. First, an optimum sintering conditions of matrix in Al and Aluminum silicon eutectic alloy (Al-12Si) are considered, by measurement of porosity ratio, Vickers hardness test, and microscopic observation. And then, a relationship between microstructure of the composite and the hardness are considered. According to the experimental results, the composite with Al-12Si has lower porosity ratio than the composite without Al-12Si. The Vickers hardness correlates highly with the porosity ratio.

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The part of rail joint becomes the cause of the disadvantage points such as ride discomfort, undesired sound and track maintenance, etc. For restraining those points, the long rail made by welding the standard length rails has been developed. However, the occurrence of buckling is pointed out. The problem of the overhang or breakage by buckling is caused by the axial force produced in the rail. The stress produced by the force is called thermal stress. The stress is brought out by the weather conditions or the friction heat between wheel and rail. Though some evaluation techniques for the buckling management are produced, the development of the technique with non-destructive testing which quantitatively evaluates the force at the good accuracy and reduces the labor for measurement worker is desired. In this study, the relationship between the increase in compressive stress and the behaviors of characteristics of ultrasonic echo was researched. The stress was increased in 10 MPa interval, and the echo at that time was detected. From that experimental results, it was found that the frequency analysis results of detected echoes fluctuate with the increases in the stress. Especially, it became clear that there is the strong correlation between the ratio of the maximum wavelet coefficients (RMWC) of a wavelet transform result (i.e. a kind of time-frequency analysis) of each echo and applied stress. Therefore, it was possible to show the possibility of comparatively accurately predicting the force by comparing the transition of the RMWC to that of the initial state.

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Titanium aluminides have some attractive properties such as low density, high strength, high melting point and good creep, corrosion and oxidation resistances at high temperature. So, it is expected as a heat-resistant material and structural material. However, its disadvantage such as low ductility and strength at room temperature make difficult to put to practical use. This work try to improve strength at room temperature by the addition of TiC and TiB as a reinforcement. TiC/TiAl-Nb and TiB/TiAl-Nb composites were fabricated by spark plasma sintering (SPS) process using mixed powders of pure Ti, pure Al and NbC or NbB_2. TiC/TiAl-Nb and TiB/TiAl-Nb composites showed a maximum tensile strength and elongation in TiC volume fraction of 5% and TiB volume fraction of 15%. The Vickers microhardness increased as volume fraction of reinforcement increased. The addition of TiC and TiB led to grain refinement. However, grain growth was observed in the composite with over the Nb atomic mass of 7%.

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Fine ceramics has various excellent properties such as mechanical electrical properties and attracts as materials for dies and molds. However, because of many of its excellent properties such as high hardness and heat-resistant, processing methods are often become problem. One of the main processing methods of the fine ceramics is grinding, which cannot be expected as an efficient processing. In this study, the grinding process by the machining center has been executed and found more efficient grinding condition for drilling around 1mm in diameter and 3mm in depth hole for positioning pins of semiconductor dies made of newly developed zirconia ceramics. Plane grinding that assumed die sinking was also performed. As experiment results, over 3mm of the total depth of the grinding of the radial direction and over 8m of the total distance of grinding can be achieved. The results are thought as a reasonable efficiency for die sinking processing.

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Hydrogen storage alloy is expected as one of the promising storage system and it has the advantages that are higher safety and hydrogen storage density per volume than other storage systems. There are several kinds of the materials and the Mg based alloy is an attractive one for hydrogen storage one. Because of the density up to 7.6 wt.% in the reversible Mg hydride, the light weight and the reasonable price. In this research, they were prepared that the cold rolling Mg-foil, the Mg-foil deposited with Fe and Pd, and the Mg film deposited on a substrate and then deposited with Fe and Pd. Each hydrogenated films was examined with the X-ray diffraction (XRD) and the films which had formed hydride were carried out the differential scanning calorimetry (DSC) to characterize the hydrogen desorption temperature. From the results, we examined the thickness effect of Mg layer in hydrogen storage properties.

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Press shaving is removing the rollover and fractured surface on cut surface obtained by shearing. It is known that the rollover will be reduced when using negative clearance in punching. Therefore, the rollover can be reduced by shaving after half punching with negative clearance. However, smooth surface is also reduced. In this study, the shaving using the protrusion punch after half punching with negative clearance was carried out to increase the smooth surface. The smooth surface obtained by shaving using protrusion punch after half punching with negative clearance is larger than that obtained by shaving after half punching with negative clearance. Moreover, rollover obtained by shaving using protrusion punch after half punching with negative clearance is smaller than that obtained by conventional punching and conventional shaving.

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A cavitation inception theory of a vapor bubble in flowing water is presented taking account of a set of fluid dynamics boundary conditions for nonequilibrium evaporation or condensation at the bubble wall. The boundary conditions are the ones for the vapor velocity and the vapor temperature at the wall, and are the solution of the polyatomic type of ES-BGK Boltzmann equation. The evaporation rate and the vapor-liquid temperature discontinuity at the wall can be correctly treated in a molecular level. The theory considers the translational motion of the bubble in flowing water with arbitrary relative velocity between the bubble and the water. The translational motion reduces the liquid pressure at the wall, and an inception process of cavitation is thereby influenced greatly. The liquid temperature at the wall is also essential for estimation of the evaporation rate, thus heat conduction equation for water is solved by two methods; one is analytical method using a similarity variable and another is numerical one based on the finite difference method.

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Liquid cooling technology has become more important for cooling heat-emitting small IT devices these days. Boiling heat transfer is one of the solutions to the requirements. In boiling phenomena inside mini channels, it is important to understand the bubble behavior and movement. In the present study, we performed fundamental experiments and numerical simulation about air bubble movement in pure water inside mini tubes. Moreover, we investigated the influence of tube shapes (circular or rectangular) on the bubble movement.

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In high-voltage equipment, partial discharge in the void present in insulation layer is directly connected to product lifetime. In order to optimize the mold structure and molding condition for suppressing the void, it is effective to numerically analyze the void behavior which cannot be directly visualized in the mold. To predict void behavior in molding process, it is necessary to formulate the void terminal velocity under inner parts in various liquid. In this work, to construct the void behavior analysis technology, we measured terminal velocity of the void rising under the inclined plate as an alternative for inside wall of mold construction and inner parts in various liquids, and developed the high precision prediction formula. By the experimental results, drag coefficient (C_D) is expressed as a function of Re and Morton number (Mo) when Reynolds number (Re) is low. By contrast, C_D is expressed as a function of Eotvos number (Eo), inclination angle of wall (θ), and Mo when Re is high. We developed the predictive formula of C_D based on above knowledge, and enable the high precision prediction of terminal velocity of the void rising under the inclined plate compared with existing predictive formula for free-rising void.

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Mass transfer from a bubble to the surrounding liquid plays an important role in industrial applications. In our study, we discuss the relationship between the mass transfer, the bubble motion and bubble-induced surrounding liquid motion, on the basis of precise visualization. Moreover, we consider influences of the bubble-surface contamination on the above motion. In our experiments, we used purified water and 500ppm 1-pentanol solution. The dissolution process of CO_2 was visualized via LIF/HPTS (a fluorescent substance) method from front view and side view of the bubble. From these experimental results, clear horse-shoe-like vortices were observed from the bubble rear both in the first inversion section and the second inversion section in purified water. The horse-shoe-like vortices promoted the mass transfer. In contrast, the surfactant induced the vortex structure change in contaminated water. It caused the mass transfer reduction.

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Foam is encountered in many industrial fields and affects safety and efficiency of floatation, wastewater treatment, and so on. However, the conventional foam measurement techniques measure only an average foam diameter near a transparent wall. Hence, we propose a new technique to measure dense foam through a single-tip optical fiber probe (S-TOP). In past study, we analyzed optical output signals when the S-TOP pierced two parallel thin films via experiments and computations. In this study, we measured a small foam cluster using the S-TOP and visualized the experiment through a high speed video camera. Based on this, we established a new system to measure both foam sizes and thickness. The measurement error was ±10 %.

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Behavior of a droplet on a vibrating plate is simulated by an incompressible SPH method with a surface tension model based on the inter-particle attraction. Vibrating frequency is chosen so that the surface deformation of the droplet will become the maximum. As a result, it is shown that the mixing inside a droplet is enhanced by vibrating the plate.

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Droplet impacts on solid wall are key elements in technical applications, such as rapid spray cooling, ink-jet printing and semiconductor cleaning. There exist varieties of physical parameters proposed that control the droplet impact although they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. After droplet impacts on solid wall, characteristic flows called lamella and splash occur. We examine the effects of the surrounding gas on droplet impacts by observing these flows. In this study, We experimentally observed the high-temperature droplet impact on smooth surface in a vacuum chamber with a high-speed photography, in order to clarify the effects of the temperature of the surrounding gas. The results show that the splash can be suppressed by increasing the temperature of the surrounding gas. We examined splash threshold proposed by Wal et al. to find that this splash threshold cannot be applicable at high temperature.

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It is essential to understand mechanisms of splash formation because droplet impacts on solid surface are key elements in technical applications such as semiconductor cleaning, ink-jet printing, spray cooling and pesticide spraying. There are many physical parameters proposed that control splashing formation after the droplet impact. Impact velocities are one of the most important parameters. In the range of high impact velocities, splash formation has been hardly investigated partially because droplets with high impact velocities can't keep spherical shapes due to the effect of air resistance. In this study, we developed high-speed droplet injector using syringe and observed droplet impact on acrylic surfaces with a high-speed photography. The result shows that the droplet dynamics after the impact is closely related with the radius of curvature of the droplet. We compared our results with the splash/non-splash boundary reported by Wai et all. (Exp. Fluids. 40 (2006) 53-59). We also investigated the relation between the radius of curvature of the droplet and the splash velocity to find that the splash velocity increases with the increase in the radius of curvature of the droplet.

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When two parallel plates confining a viscous fluid in a narrow gap between their plates separate from each other at a constant velocity, the free surface of the fluid is disturbed like a dendrite or fingers. This phenomenon is referred to as meniscus instability. In the present study, two phase flow analysis program by finite difference method was developed to investigate the meniscus instability numerically. The Stokes-Brinkman equation was solved to obtain velocity and pressure field. Identification of interface in one fluid model was carried out using the level set method. The continuum surface force model was used to take surface tension into consideration. To verify the validity of the program, axisymmetric flow in Hele-Shaw cell in which air injects into silicone oil was calculated and the numerical results showed quantitative agreement with theory.

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In this paper, an Interface-Tracking method combined with the Moving-Grid Finite-Volume method is presented for simulating the free surface flows. Free surface flows are important from a point of view of engineering. For example, sloshing flow in tanks, mixing in vessels, jet from nozzle and injection molding are free surface flows. Many numerical methods are presented for free surface flows. These method can be classified to two approaches, interface-capturing method and interface-tracking method. We use Interface-Tracking Method. In the Interface-Tracking method, the calculation grid is moved and deformed according to the movement of the free surface. Surface height equation is used for the free surface shape determination. The purpose of this paper is to extend the Moving-Grid Finite-Volume Method to free surface flows. The main advantages of this method is simple treatment with free surface and satisfying physical and geometrical conservation laws. We applied this method to some flow cases with free surface. As test cases, sloshing flow in a tank is presented. Numerical results show that the present new Interface-Tracking Moving-Grid Finite-Volume method is very accurate and have a promising feature for moving boundary problem with free surface.

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Welding process is expanding to various fields because of its rapidity and accuracy. And, precision of shape of the workpiece of this is needed more than before. It is difficult to predict shape of workpiece because welding process includes multi physics including flow of pool and thermal dynamics. Moreover this process needs high energy as heat input, so real-time observation is difficult because of generating a high temperature and luminance in welding process. In this present, we show usability to compare cross-section of workpiece between computational simulation and experiment in laser welding.

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We discuss the orientational properties of an oblate spheroidal hematite particle in a simple shear flow under the situation of a uniform external magnetic field, by means of an analytical approach based on the orientational distribution function. Magneto-rheological properties are strongly dependent on the direction of an applied magnetic field. In the present study, we consider the case of an external magnetic field applied in the direction of the angular velocity vector of a simple shear flow. An oblate spheroidal hematite particle is magnetized in a direction normal to the particle axis. The basic equation of the orientational distribution function has been numerically solved. If the rotational Brownian motion is much more dominant, the particle does not exhibit specific directional characteristics. If the magnetic field is much more dominant, the particle inclines such that the particle almost freely rotates with the magnetic moment inclining in the magnetic field direction. If the shear flow becomes a significantly governing factor, the particle exhibits a usual single peak-type orientational distribution similar to that of a polymer molecule in a strong shear flow. The viscosity due to the magnetic particle-field interaction does not arise in the present magnetic field direction.

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Magneto-rheological properties of a magnetic particle suspension are strongly dependent on the formation of aggregates of magnetic particles. A suspension of ferromagnetic rod-like particles can be expected to exhibit strong magneto-rheological characteristics, which is a significantly important factor for application of magnetic particle suspensions to mechanical dampers and actuators. Hence, in the present study, we address a suspension composed of ferromagnetic rod-like particles in thermodynamic equilibrium. Monte Carlo simulations have been carried out in order to investigate the dependence of the phase change hi aggregate structures on the magnetic field strength for various cases of the magnetic particle-particle interaction strength. The cluster formation of magnetic particles significantly appears for a strong magnetic interaction larger than a certain value. As the applied magnetic field strength is increased, the clusters come to dissociate into small clusters, and finally at a certain strong applied magnetic field, all clusters completely dissociate into single-moving particles. This clearly exhibits that an applied magnetic field induces the phase change in a magnetic rod-like particle suspension.

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Magneto-rheological properties of a magnetic particle suspension are strongly dependent on the formation of aggregates of magnetic particles. A suspension of ferromagnetic rod-like particles can be expected to exhibit strong magneto-rheological characteristics, which is a significantly important factor for application of magnetic particle suspensions to mechanical dampers and actuators. Hence, in the present study, we focus on a ferromagnetic rod-like particle suspension to discuss the magneto-rheological properties. The results were obtained by means of Brownian dynamics simulations in a simple shear flow situation. In a weak applied magnetic field, magnetic rod-like particles tend to aggregate to form raft-like clusters, and with increasing magnetic field strength, these raft-like clusters drastically dissociate into single-moving particles at a certain value of the magnetic field strength. The net viscosity and its viscosity components exhibit complex dependence on the magnetic field strength, which is mainly due to the raft-like cluster formation of magnetic particles.

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Water scarcity is a serious problem around the world in the 21st century. Reverse osmosis (RO) which is a technology that uses a semipermeable membrane is used to remove ions from sea water. However, this method has a problem that separation performance falls gradually with the operating time due to fouling and concentration polarization at the membrane surface. In this study, molecular dynamics simulations were carried out to investigate the effects of interaction force between solid and liquid on the diffusion of water molecules near the solid surface. The results show that the strong interaction force decreases the diffusion coefficient of water molecules in the vicinity of the solid surface, and there is a strong correlation between the diffusion coefficient of water molecules and the contact angle of water on the solid surface.

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This paper discusses easy way to determine Elasto-viscoplastic parameters for numerical simulation of fresh concrete flow. Slump tests and L-Flow tests are commonly performed at construction site in order to survey consistency of fresh concrete flow easily, so it is ideal to use results of these tests. Simplified analysis of slump test leads the fact that yield stress influences the slump value, and numerical simulations with varying parameters endorses the fact. Simulation shows that shear modulus also affects slump when slump is small. However viscosity does not affect slump value at all, but does only concrete velocity. So set of yield stress and shear modulus can be determined by the results of slump test and graph of yield stress evaluation of simulated slump value. And determination of the viscosity requires experiments measuring flow velocity test such as L-flow test.

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Damaged stability is mainly assessed by the static calculation. However, recent advance in computational fluid dynamics could enable us to predict the dynamic fluid motion and as well ship motion in the near future. Therefore, in this research, flooding and sinking due to damage opening, are experimentally measured for using simple floating model. On the other hand, the numerical simulation by using MPS (Moving Particle Simulation) method is conducted for same experimental conditions. MPS method is one of particle simulation methods which use moving particles interacting with each other instead of fixed calculation grids. This method can easily handle large free-surface deformation including fluid breakup, coalescence and fluid-rigid body interaction problems as well. As a first step to validation, the motion of the floating model is allowed only in vertical direction and MPS calculations were done in 2D. As a result, it is concluded that MPS method practically predict the fluid motion and ship motion obtained by the experiment.

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We present a new lattice Boltzmann method for the wave propagation in isotropic elastic body. Since this model uses same algorithm for previous LB model for fluid analysis, it is easy to implement fluid-structure interaction (FSI) simulation program. In this paper, we conducted ID and 2D elastics simulation to validate this model. And also, we demonstrate ID FSI simulation which uses our model and previous model for thermal fluid.

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In recent times, pulmonary drug administration using an inhaler is a subject of interest. The efficient delivery of drug particles to the lungs requires a realistic model of flow patterns in the alveoli. Numerical simulation is a useful tool for studying this airflow. However, simultaneously dealing with alveolar expansion/contraction and the airflow caused by alveolar deformation has proved challenging, because the alveolar sac has a complicated structure. This study develops a model in which inflow into and outflow from the alveoli were modeled by introducing a mass source term into a mass conservation equation. Our model was first validated using a simple calculation area, i.e., the flow pattern calculated by our model was compared with that calculated using a moving boundary condition. The two models showed similar flow patterns. Furthermore, the flow in an alveolar model constructed from a CT image was calculated using our model. The results demonstrated vortexes in the alveolar sac when the flow shifted from inflow to outflow, which is consistent with previous studies.

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Inhalants, such as bronchodilators, are often used to treat asthma. Computer fluid dynamics (CFD) can be applied to quantitatively evaluate the transport and deposition of medicinal particulates in the respiratory tract. In this study, the oral cavity, the pharynx, the larynx, the trachea and intra-thoracic central airways of up to 7 generations were modeled based on a CT image of a human lung. There are a total of 42 peripheral airways. Air flow and particle motion were simulated by Large-Eddy Simulation (LES) in a CFD software OpenFOAM ver 2.3.1. The inflow condition assumed such a respiratory pattern when an inhaler is used, i.e., inhalation followed by breath-holding, and the air flow and particle motion during inhalation were analyzed. The flow velocity reached maximum at the throat. Difference in particle size affected the transport and deposition of the particles in the respiratory tract, and many particles deposited in the branches of the respiratory tract and the throat.

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On a birth of preterm infants with respiratory distress syndrome (RDS), an emergent treatment should be applied with a surfactant, then a continuous positive airway pressure (CPAP) will be adopted to the infants in a newborn intensive-care unit (NICU). As the improvement of CPAP, we have developed a bypath nasal-CPAP device with a spontaneous respiration simulator (PT-2). The simulator is driven by a diaphragm and can supply the exponential, triangular, and half sin wave forms as the inspiratory breathing. In the present paper, we have tested a fundamental characteristic of the vertical typed BNCPAP for theses forms. The pressure fluctuation in CPAP cavity for these wave forms shows no difference in amplitude, but the wave phase was different. As a result, the vertical BNCPAP found new type device that is response respiration flow.

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Two-dimensional flow developing between an inner solid rectangle and a hollow outer rectangle is investigated by the numerical approach. The rectangles are squares and they are placed coaxially and in the same phase. One lid side of the outer square or one lid side of the inner square is the boundary where the lid moves in the tangential direction. The unique geometrical parameter is the aspect ratio defined by the fraction of the side length of the outer square to that of the inner square. When the one lid of the outer square moves, the flow includes vortices at stationary boundary corners and the upstream stationary wall similarly to the single square cavity flow without the inner square. The inner square deactivates the development of the global vortex and small vortices appear on the side of the inner square. When the flow is driven by the inner side lid, four flow patterns appear: the steady tangential flow pattern, the steady deflected flow pattern, the one way flow pattern and the oscillating flow pattern. The tangential flow pattern appears at relatively smaller Reynolds numbers or the smaller aspect rations. The oscillating flow pattern emerges at higher Reynolds numbers. At the aspect ratio above 3.0, the flow tends to have one way flow pattern around the inner square regardless of the Reynolds numbers. In addition to the traditional single cavity flow, the dual cavity flow investigated in this study is expected to give a new benchmark system including steady and unsteady flows.

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We carried out phase-locked Tomographic PIV measurements in a square shaped, vertically-oriented water tank, in order to understand its general flow behavior and turbulence shear stress distributions in detail. The three-dimensional experiments are carried out at four different, 40 mm thick, vertical volume sheets. The water is stirred by a commercially available impeller, which has three symmetrical twisted blades. The impeller is rotated at the constant angular speed of 150 RPM. The Reynolds number of the flow, based on the blade's tip velocity and the impeller diameter, is 59400. In the present study, we carry out the flow measurements at two angular locations, so that the combined flow field would enable us to fully understand how the tip-generated vortices bend and diffuse in the flow domain. Exploring behavior of the tip-generated vortices are of prime interest to us, because the turbulence kinetic energy happens to be primarily concentrated inside these vortices.

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Measurements were made of mean and fluctuating velocity profiles in the wake flow of the five kinds of stepped circular cylinders varying the diameter from a big one to a small cylinder at the midpoint of the span. Furthermore, we measured vortex shedding frequencies and compared them to that of a straight cylinder. Hot-wire survey shows that mean velocity profiles were largely distorted in S-shape depending on the diameter rations of cylinders in the center line of the cylinder, moreover, having the flat-type and W-type in shape at the big cylinder underneath the step. In addition, turbulent intensity were at same regions where mean velocity profiles having the flat-type shape. This indicates that the secondary flow induced by the longitudinal vortices disturbed the velocity field of wake flow. As a result, vortex shedding frequencies decreased linearly with the diameter ratios and velocity fluctuation induced these vortices were decreased at the big cylinder.

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The inter-laboratory comparison has been carried out in the flow rate range between 10 L/h and 300 L/h with light oil in order to assess the calibration uncertainties of the small calibration facilities for hydrocarbon flow at two laborites, NMIJ and ONOSOKKI. A piston type positive flow meter was selected as a travelling meter and the effect of the flow meter due to flow rate, temperature, pressure, viscosity and between-day variability has been investigated by using the NMIJ calibration facility in detailed in order to evaluate the uncertainties due to different calibration condition between the two laboratories. Resulting that the uncertainty due to the flow meter at 20 L/h to 300 L/h is less than the calibration uncertainties at both labs, the selected flow meter is suitable. However, the comparison at 10 L/h is inappropriate, since the uncertainty due to the flow meter is larger than the uncertainty at each lab. Furthermore the two calibration facilities between 20 L/h and 300 L/h at the two labs agree within the quoted expanded uncertainties.

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A liquid low-flow calibration rig has been developed, which is consisted of a syringe pump and a gravimetric weighing tank system. A flowmeter is calibrated using the syringe pump to overcome issues on the low-flow rate and on the standing method. Calibration flow rate range of this one syringe pump is from 0.3 mL/min〜1000 mL/min (0.02 L/h to 60 L/h). For this purpose the syringe pump system was designed employing a servo-motor, a precise ball screw and a linear encoder. The syringe pump has been calibrated using the weighing tank at all flow rate range to check and extract latent problems in the whole calibration system. The weighing tank system has been improved to reduce influence of evaporation and outlet tube contact. The syringe pulse factors have been calibrated in all flow rates with light oil and industrial gasoline and they all agreed within ±0.02%. Preliminary expanded uncertainties of the low-flow rig have been estimated to be 0.066% for mass flow and 0.070% for volumetric flow.

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An inner-laboratory comparison for water flow calibration facilities with high accuracy, in other word, very low uncertainty is performed between Endress+Hauser Japan (EHJ) and Advanced Industrial Science and Technology, National Metrology Institute of Japan (AIST, NMJ.J). Flowrate range examined in this comparison is from 31 kg/h to 36000 kg/h. The expanded uncertainties at EHJ and at AIST, NMIJ are estimated to be 0.020% - 0.025% and 0.021% - 0.023%, respectively. The transfer meters are Coriolis flowmeters. The comparison results show nice agreement. The difference between two labs is within 0.02% and En value is less than 0.6. Especially, for flowrate more than 10000 kg/h, the difference is less than 0.01% and En value is less than 0.2.

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We measured the discharge coefficients of critical nozzle using hydrogen and nitrogen gases at high-pressure and high Reynolds number (Re = 2.5 x 10^5 - 2.2 x 10^6). It were confirmed that the discharge coefficients deviated from the universal curve prescribed in ISO9300 and decreased with increase of the theoretical Reynolds number, though the values of discharge coefficient differed between two gas species. It was also confirmed that the critical nozzle flowmeter could be adopted as the transfer standard for an intercomparison by using a correction factor of the theoretical mass flow rate.

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