The Doi equations have been directly computed for shear and extensional flow without closure approximations. An extension is imposed on the shear flow plane. It is well-known that for simple shear flow there are three orientation regimes, depending on the magnitude of shear rate; rotational (tumbling), oscillatory (wagging), and stationary (aligning) orientation behaviors. When we add an extension to simple shear flow, the time period of tumbling is increased, while the order parameter in the regime is almost unchanged. In the wagging regime, however, both the time period and the order parameter are increased. Transitions from the tumbling and wagging regimes to the aligning regime are induced when more than a certain magnitude of extension is imposed on a system. An extension has also an effect to make the first normal stress difference positive. Furthermore, motion of individual molecules has been analyzed by integrating the Langevin equation. It is found that the aligning state in shear and extensional flow is due to an approximately stationary behavior of individual molecules, while the aligning state in simple shear flow is an apparently stationary behavior of a group of many rotational molecules.

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It is well known that fluid dynamical phenomena in arterial blood flow can play an important role in arterial diseases. Flow between flat plates with asymmetric stenosis is analyzed numerically. The fluid is assumed to be Newtonian and incompressible, and the flow is assumed to be periodic in time. It is found that the vortex downstream of asymmetric stenosis becomes strongest at a certain frequency of pulsation. This phenomenon is called vortex resonance in this paper. The flow pattern, the vortex strength and the distributions of wall shear stress are obtained. The results show that the resonance frequency changes with wall configuration and Reynolds number. The vortex resonance occurs where the difference between the adverse pressure and the friction on the wall is maximum.

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The flow around a sphere on a flat plate is investigated experimentally for the purpose of lifting the sphere by a suction flow from an inlet over the sphere. The experiments are carried out using air flow in the atmosphere. The lifting force exerted on the sphere is measured by using balances. The pressure on the surface of sphere is measured using pressure holes. The flow around the sphere is visualized using titanium tetrachloride and the tuft method. Several kinds of inlets are tested. It is concluded that the inlet of suction pipe with concentric annulus, which is composed of the outer pipe for jet flow and the inner pipe for suction flow, is suitable for lifting valuable mineral deposits on the ocean floor.

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Numerical simulations by a finite-difference method have been made for a viscoelastic flow due to a rotating disc enclosed in a cylindrical casing with relatively large axial clearance. The Giesekus model, modified Giesekus model and Phan Thien-Tanner model were applied as the constitutive equations. Using particle tracking velocimetry (PTV), the effects of rheological properties on the distribution of the velocity component V_θ and the secondary flow were clarified. By comparing the experimental results with the numerical simulations the validity of the respective viscoelastic fluid models were examined. The secondary flow patterns observed by flow visualizations were characterized by the elasticity number (=Weissenberg number/Reynolds number). It was confirmed experimentally that near the rotating axis there was a place where the tangential velocity component was negative for the cases of 0.3 wt% and 1 wt% polyacrylamide aqueous solutions.

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We have extended the CIP (Cubic Interpolated Pseudo-particle) method to the FEM (Finite-Element method) in our previous works. The previous verifcations of GSMAC-CIP scheme were, however, done by using the orthogonal meshes and we don't make use of the characteristic of the FEM. In the present work, GSMAC-CIP scheme is applied to the flow around a circuler cylinder and employs arbirary meshes. That flow is a famous problem which has been studied by many investigators. Therefore, good numerical and experimental data, for example the experimental data obtained by Bouard and Coutanceu, are available easily. The Reynolds numbers are Re=550, 3 000 and 9 500. The numerical results are compared with the experimental data obtained by Bouard and Coutanceu, and the effetiveness of the present scheme is shown. Moreover, we point out the mistakes of their experimental data for the velocity profile on the center axis behind a cylinder at Re=9 500.

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Numerical simulations of three dimensional flow in a spool valve have been made to investigate the flow force acting on the spool. The spool valve adopted here was practical hydraulic type having non-axisymmetrical flow paths with inlet and outlet ports located near the valve orifice. The flow field around the valve orifice was numerically simulated by a quasi-direct simulation based on the finite volume method using a co-location grid. The flow patterns around the spool such as jet angle, reattachment point of jet and vortices generated downstream the valve orifice were found to be non-axisymmetric. The distribution of momentum flux in the azimuthal direction at the valve orifice was strongly influenced by the flow separations at the edge of inlet port and the surface of spool. The non-uniformity of the distribution became mitigative with decreasing the spool stroke.

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A statistical theory is applied to the modelling of turbulent correlations for dispersed dilute two-phase flows. And a k-ε model for the two-phase flows is derived. The experimental data of two-phase turbulent flows of air and solid particles in a round jet is used to validate the proposed model. The predictions of the profiles of mean velocities of both phases and the turbulent shear stress of the gas-phase show good agreement with the experimental data.

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Three dimensional computations were performed using the KIVA-3 code to investigate the unsteady compressible turbulent flows about a practical train passing through a single-track tunnel. Both length of the train/tunnel and speed of the train were considered to investigate their effects on the train-tunnel interaction. In order to understand the whole process of the train-tunnel aerodynamic interaction, we studied the formation and propagation of the pressure waves, the reflection and radiation of the waves at the tunnel portals and the histories of aerodynamic forces on the train. The experimental results were compared well with the computational data. The code can be used to predict the aerodynamic phenomena of the train-tunnel system.

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As is well known when a shock wave is emitted from an open end of a tube, an expansion wave and a vortex ring are generated behind the shock wave. Furthermore, a contact surface, slip line and these wave interactions may cause considerably complicate flow-fields. In this study, shock waves of Mach number 1.3, 1.6 and 2.2 are produced utilizing diaphragm-less shock tube of 50 mm diameter and c. a. 10 m total length, and the flow-fields are visualized with an aid of schlieren optical techniques. A cylindrical reflector is installed at test section and stagnation pressure behind reflected shock wave is measured with wide frequency response. A numerical analysis is also carried out to investigate these flow-fields using Predictor-Corrector TVD finite difference scheme. As a result, (i) the contour of diffracted shock wave is well coincided between experimental and numerical results, (ii) pressure histories behind reflected shock wave are clarified, (iii) an empirical formula is obtained between Mach number, non-dimensional distance from the open end of the tube and non-dimensional pressure just behind reflected shock wave.

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A modified drift-flux model is developed for analyses of two dimensional gas-liquid and solid-liquid two-phase flows. The basic idea lies in a hypothesis that as far as the drift velocity is concerned, a dispersed phase wiI1 behave in a modified gravitation or acceleration field g' that includes, among others, the centrifugal acceleration effect due to curvatures of streamlines, without distinction between accelerations due to different forces. Therefore, the terminal velocity of the dispersed phase in the continuous phase can be obtained by simply replacing with g' the gravitation field g in the correlation of the terminal velocity obtained by a simple one dimensional experiment. Two-dimensional numerical analyses based on the drift-flux model were performed to analyze those dispersed phase flow structures in a tank filled with saturated water. By comparing the numerical results with the experimental observation, the validity of the drift-flux model for the case of multi-dimensional multi-phase flows was investigated.

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Studying the limiting gas velocity at which conveying is possible in a state in which particles are not stagnant on the wall of the pipe, called 'minimum transport velocity', is very important in terms of saving energy for transportation. However, relating to a pipe bend, concepts concerning the minimum transport velocity are few up to this time since the particle motions in the pipe bend are very complicated. From such viewpoints in this paper a basic model equation of the minimum velocity in the pipe bend is first introduced for the dilute phase flow in conventional pneumatic conveyance. Next, the minimum velocities are measured in an actual transport experiment for coarse particles. By analyzing the measured data, an unknown in the basic equation is determined and an empirical equation of the minimum velocity is provided. The experiments are carried out on the condition that the curvature radiuses of the right-angled bend from the horizontal to the vertical are 300, 500 and 700 mm, the pipe line is 10 m long and 50 mm in diameter, and the conveyed particle is Polyethylene pellet with particle diameter of 3.4 mm.

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The flow through a curved rectangular duct with the curvature=0.1 is investigated numerically at the Dean number Dn=100 for various aspect ratio of the duct cross section by use of the spectral method of the polynomial function expansion. Resistance coefficient of the duct flow is calculated in terms of two different ways for all the steady solution branches which have been obtained in the previous report. The relation between the values of resistance coefficient and the linear stability characteristics of the steady solutions is studied. It is found that linearly stable solutions exist on the branches for which the resistance coefficient is largest or second largest. The axial velocity distributions are examined comparing with the secondary flow patterns in the cross section.

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An experimental study has been carried out for the developing flow in a curved 270 deg pipe without upstream tangent. Three components of mean and fluctuating velocities were measured by the technique of rotating a probe with an inclined hot wire and an intermittency factor was obtained from the wavy form of axial velocity component under a Reynolds number of 120 000. The flow patterns of main and secondary stream, and the distribution of the intermittency factor in pipe section are illustrated with figurers and explanations are added on the process of phenomena in the streamwise direction and the transition from non-turbulence flow to turbulent flow. Also, the experimental results are compared with these of the curved pipe flow with upstream tangent and the influence of the upstream tangent on the curved pipe flow are examined.

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Primary and secondary Reynolds shear stresses, -(u'v')^^^- and -(v'w')^^^-, have been measured with a two-component LDV in a fully developed turbulent square-duct flow. Quadrant analysis has been performed for these Reynolds stresses in order to demonstrate typical flow structures responsible for their generation. In the near wall region close to the wall bisector, the primary Reynolds stress is generated by streamwise vortices through both ejection and sweep motions in a similar manner to turbulent boundary layers and two-dimensional channel flows. In the near-wall region apart from the wall bisector, on the other hand, the contribution of a sweep motion to the primary Reynolds stress is significantly reduced. In the corner region, apart from the wall bisector, the secondary Reynolds shear stress is induced by fluid motions from one wall toward another wall via an antisymmetric streamwise vortex. These motions transport the streamwise momentum near one wall, which is lower than that close to the wall bisector because of the no-slip constraint by the wall, toward another wall. As a result, in the corner region relatively-low-speed fluids inrush toward the wall, which leads to the reduction of a sweep motion apart from the wall bisector.

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A novel axisymmetric jet nozzle equipped with a row of miniature electromagnetic flap actuators on its circular lip is developed for active flow control. Each of the flaps fabricated by photolithography is independently driven according to a control signal supplied by a PC. The spatio-temporal flow structures of the controlled jet are studied through flow visualization and quantitative velocity measurements. It is found that artificial disturbances generated by the flaps can modify the formation and evolution of large-scale vortical structures significantly. When each half cluster of the 18 flaps are driven out of phase, the jet bifurcates clearly into two branches owing to the interaction between alternatively inclined vortex rings. The optimum Strouhal number, at which the centerline velocity drops to about 45% of that of natural jet, is found to be 0.25 at the jet Reynolds number up to 13 000. A physical model for the bifurcating jet is proposed based on the flow visualization and the phase-averaged velocity and vorticity fields measured by two-dimensional particle tracking velocimetry.

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Hollow-jet valve has been utilized to control the water supply extensively under high static pressure. For the valve used underwater, cavitation erosion will probably be caused. However, such a trouble has not been studied yet in detail. Therefore a similar model of hollow-jet valve was made in which plunger stroke is changeable as the prototype valve. The aim of this paper is to clarify the characteristics of cavitation-induced vibration related to the erosion around the upstream casing and six splitters in the valve, to estimate the ventilation effect to decrease the erosion as well as the vibration, and also to make clear the difference of flow pattern in the valve between underwater and in air.

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An experimental investigation was made to clarify the characteristic of oscillating cavitation on a flat plate hydrofoil in a water tunnel. Dynamic behavior of oscillating cavitation is discussed based on the unsteady pressure upstream of the blade and visual observations using high speed video recording. It was found that the fundamental oscillating characteristics depend on the mean cavity length. For cavities longer than 75% of the chord-length, the Strouhal number based on the chord-length is nearly constant 0.13 and independent on the angle of attack and the inlet duct length. Re-entrant jets are observed and their effects are discussed.

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The vibration properties of a coupled system of magnetic fluid and elastic membrane under impulsive magnetic field have not been clarified. In this paper, vibration of a coupled system of water-based magnetic fluid and circular elastic membrane is investigated experimentally. A thin elastic membrane covers a magnetic fluid layer in a shallow and circular vessel. The coupled vibration is generated by applying external impulsive magnetic forces on the concentrated small region of the magnetic fluid layer. The vibration modes are studied both when axisymmetric and non-axisymmetirc impulsive magnetic forces are applied. Various vibrations are observed depending on the physical parameters such as the density of magnetic fluid, the depth of the fluid layer and the thickness of the membrane.

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The present wind tunnel experiment verified streamwise development of internal gravity waves from their spontaneous generation to collapse into turbulence. Strongly stably-stratified mixing layer was realized in which the maximum local temperature gradient reached about 1 100 K/m and the local Richardson number exceeded 0.25. Simultaneous measurements were made on instantaneous temperature and velocity fluctuations in the mixing layer. Energy density levels of quasiperiodic components of temperature and velocity fluctuations below the Brunt-Vaisala frequency increased rapidly downstream and the internal gravity waves having frequency components of 1.0 Hz, 1.8 Hz, 2.8 Hz were confirmed to develop in the streamwise direction. The phase difference between the vertical component of velocity fluctuation and temperature fluctuation approached -π/2. The constitution of fine structure of the internal gravity waves swung in time as they grew downstream. The energy of their low-frequency components were transported toward the higher frequency components through their nonlinear interaction and the internal gravity waves collapsed into turbulence locally in the mixing layer. Then, the stably stratified flow field was rapidly broken down.

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The performance of a small hydrocyclone is examined experimentally for solid particle separation from water. The cyclone has an inner perforated cylindrical tube connected to the overflow orifice, and a conical cylinder is inserted into the underflow orifice to adjust the underflow flux. Two types of the inner cylinder were tested: the one has 50% void fraction of the perforated surface and the other has 61.2%. The glass bead was used as a solid particle whose average diameter is 4.84 μm. It is found that the hydrocyclone with the inner perforated cylinder shows better performance: When the cyclone has 50% void fraction of the perforated cylinder, the decrease of pressure loss is about 30% and the increase of separation efficiency is about 15% compared with the conventional cyclone. The higher void fraction of the inner cylinder produces higher performance.

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A screw type centrifugal pump was manufactured to carry solids primarily and its impeller has a wide flow passage. However, the effect of flow passage shape on delay of the choke due to entrained air has not been clarified yet. For that reason, we carried out the pump performance experiment under air-water two-phase flow condition with different impeller tip clearances and void fractions. And we obtained the result that Δψ (loss of pump head from single-phase flow to the choke due to air entrainment) became less at a wide tip clearance than that at a narrow tip clearance. Moreover, at a narrow tip clearance, the pump head became partially higher in two-phase flow than that in single-phase flow near the best efficiency point in low void fraction region. Therefore, we have observed the internal flow pattern by using a stroboscope and measured mean size of bubbles from the images obtained by using a high speed camera. Then, we have investigated the influences of mean size of bubbles, tip clearances as well as flow patterns on pump performance.

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In this paper, the performance test is carried out by the systematical change of blade number, blade outlet angle and the Reynolds number for pumping high-viscosity liquids, and the pump performance has required the slip factor in the maximum efficiency point. It was clarified that the slip factor depends upon the Reynolds number, blade number and blade outlet angle. In addition, the experimental formula for the slip factor including blade number, blade outlet angle and the Reynolds number has been presented from these results. Then, it was confirmed that this experimental formula predicts fairy well the experimental results in the region of low that Reynolds number. Further, this experimental formula are examined by comparing with the results of Toyokura et al. and the results of slip factor using the pump head of the finite blade number of impeller. It was shown that this experimental formula was useful in practical use for region of low the Reynolds number. These impellers used for the experiment are open type and two-dimensional except the near entrance. The blade thickness is 5 mm. The blade outlet angles are 10°, 20°, 40°, 60° and 73°, and the blade numbers are 3, 4, 6 and 8. The range of the Reynolds number of the experiment is 1.78×10⁴∼2.67×10⁶.

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One purpose of this study is to investigate the morphological change of endothelial cells in a separated flow area. The other is to reveal the albumin uptake into endothelial cells, the albumin uptake area, and the its content per unit area in the separated flow area. After 24 hr of exposure to flow induced in a back step flow channel, the endothelial cells were incubated in 37°C for 60 minutes in PBS containing tetramethylrhodamine isothiocyanate conjugated albumin (TRITC-albumin). Thereafter, the cell morphology, the density, and the albumin uptake were observed by a confocal laser scanning microscope (CLSM). In low shear stress areas (stagnant and reattachment areas), the cells are round and aligned randomly. In high shear stress areas (reversal and fully developed areas), the cells are elongated and aligned to flow direction. In low-shear-stress and high-shear-stress gradient areas (reattachment areas), the cell density is low compared to the other areas, and the amount of albumin uptake into the cells is the largest in all areas because of the increase of albumin uptake areas. These data indicate that shear stress and shear stress gradients affect the endothelial cell morphology and the albumin uptake into endothelial cells.

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A theoretical study was conducted to investigate the wetting behavior of liquid meniscus on a vertical plate with three-dimensional random characteristics of heterogeneity and roughness. The thermodynamic stable condition was derived by considering the minimum of system free energy. The local stable condition leads to a result similar to that obtained for a plate with two-dimensional characteristics, i.e., the system has many meta-stable states. For the stable condition of the whole system, a relation was derived between macroscopically observed contact angle and the surface characteristics. The product of cosine of the contact angle and liquid surface tension is equal to the energy difference for the liquid to wet the plate by apparent unit area. If the liquid wets the solid surface reversibly, there is only one contact angle observed macroscopically. This fact suggests that the contact angle hysteresis is caused by the irreversible motion when the liquid advances or recedes on the solid surface. The well-known Cassie and Wenzel's contact angles are explained as those corresponding to thermodynamically stable condition when the liquid wets the solid reversibly.

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Transient measurements of thermal contact conductance are made on the interface between isotropic rough surfaces of metals in air. We present an analytical solution for temperature distribution of the one-dimensional symmetric system with the condition of time-dependent temperatures at two points in each body, and thereby interface temperature drops and heat fluxes can be obtained without the condition of heat-flux continuity at the interface. Contacting surfaces of rod samples (Naval brass, JIS·SK5 carbon tool steel and JIS·SUS 304 stainless steel) of 25 mm-diameter are uniformly polished using an Emery 320 paper. Transient characteristics of both temperatures and heat fluxes at the interface are experimentally determined using the analytical solution. It is revealed through the transient experiment that the thermal contact conductances are not constant at the early stage, but rapidly increase from zero and that the discontinuity of interface heat-flux is observed by about 20 percent for all metal pairs. For the contact between dissimilar metals, the dependence of thermal contact conductance on the direction of heat flow is not distinguishable.

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An experimental-computational hybrid system for measurement of thermal conductivity of orthotropic materials is developed. The system consists of two experimental parts and a finite element analysis part. Firstly, a temperature distribution generated by an uniform heating is measured with a thermal video system, and a thermal conductivity of Z direction is calculated. Secondary, a temperature distribution generated by a small area heating is measured with the system. In the final step, thermal transfer analyses simulated the experiment support efficient data, and thermal conductivity of in-plane directions are estimated by comparing between experimental and analytical temperature distributions. The orthotropic equivalent thermal conductivity of honeycomb materials given by this system agreed with the theoretical values.

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It is empirically well known that a moist fire protection material shows a good fire resistant characteristics. From this fact, a fire protection material is made of a mixture of cement mortar in which water storage materials such as silica gels or moist perlites are mixed. The latent heat of water in the fire protection material plays an important role in the resistance of temperature rise. In this study, the fire resistance tests for a fire protection material of high water content is conducted and the temperature response of the test material is obtained. The test material consists of the perlite motar in which the gels which absorbed the aqueous solution of calcium chloride are mixed as the water storage material. The water content of the test materials were also measured. And also the numerical predictions for the fire resistance test were conducted and the results were compared with the experimentally obtained temperature responses.

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The Critical Heat Flux (CHF) of subcooled flow boiling with water in a tube was investigated from the viewpoint of mechanistic models. The bubble crowding model by Weisman-Pei was selected to predict the CHF in the short tube and in the tube with twisted tape under nonuniform heating condition because of the results of bubble behavior observation and preliminary analysis. The original Weisman-Pei model was modified in order to explain the physical phenomena of the CHF. The newly modified model made well prediction about the CHF in a smooth tube include the very short tube and in the tube with internal twisted tape under uniform and nonuniform heating condition.

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The main purpose of the present paper was to develop a correlation which can be used to predict the critical heat flux for the upward flow in an inclined tube at high pressure. At the first step, the correlations of the critical heat flux in vertical and horizontal tubes, which had been proposed previously by the authors, were modified to agree with experimental data newly obtained. Then, a correlation of the critical quality for the inclined tube was developed as a function of the inclination angle with the values of the critical quality for the vertical and horizontal tubes used as bases. This correlation can be applied to every tube inclinations from horizontal to vertical orientation with good accuracy.

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The effects of inner rotating plate on the heat transfer in a differentially heated inclined enclosure were investigated experimentally. The aspect ratio of the enclosure height/width was 1 throughout the experiments. An acrylic plate was installed with horizontal axis at the center of the square enclosure, and was rotated at various speeds. The inclination angle of the enclosure was varied from -90° to 90°. Purified water was used for the working fluid. The flow pattern was sketched by a visualization experiment using aluminum powder. The heat transfer enhancement can be clearly seen for the inclined enclosure with hot wall of downward facing. The rotating plate used here is useful for the regulation of wide-ranging heat transfer rate.

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Experimental study was conducted on characteristics of the temperature field in forced convection turbulent heat transfer in a square duct with two opposite rib roughed walls. In particular, all three components of turbulent heat fluxes were measured by triple-wire probes, and they were compared with those obtained in a smooth walled square duct to examine the influence of rough walls on the transport process of heat and momentum in the duct. In the rough duct, both the turbulent heat fluxes and turbulent shear stresses are increased due to the turbulence-promotion effect of the rough wall. Near the smooth wall adjacent to the rough wall, the increase ratio of the turbulent heat flux relative to the smooth duct is larger than that of the turbulent shear stress. On the other hand, near the rough wall, the transport of heat by turbulence becomes less active than that of momentum, and this causes the dissimilarity between the distributions of the mean temperature and the primary flow velocity.

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An experimental study was performed to investigate the local heat transfer around a cube mounted on the wall. The cube lied in the turbulent boundary layer. The flow angle of attack to the cube was 45 degree. The Reynolds number ranged from 4.2×10³ to 3.3×10⁴. The surface temperature distributions around the cube were measured with thermocouples under the condition of a constant heat flux. The local heat transfer is very high near the front corner on the top face of the cube. This high heat transfer region extends from the front corner to downstream along both edges. This is caused by the formation of lamb horn vortex. The local heat transfer is also high in the region of horseshoe vortex formed around the cube. On the wall behind the cube, there is a pair of minimum heat transfer region. The average Nusselt number on each face of the cube is given as a function of Reynolds number. The overall Nusselt number of the cube is expressed by Nu_m=0.43Re^0.58.

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An experimental investigation was performed to determine the transient desorption characteristics of a fibrous type organic adsorbent, which was composed of the bridged complex of sodium polyacrylate as a new kind of adsorbent. The test fibrous adsorbent was packed in a cylindrical vessel, and dry air was passed through it. The experiments were conducted under various conditions of air velocity, temperature, relative humidity and vessel length. As a result, the pressure loss for the packed bed of the test fibrous adsorbent showed a similar tendency to that for the packed bed of spherical particles. The mass transfer data was correlated by the modified Sherwood number, the Reynolds number, the Schmidt number, the ratio of desorbed water vapor mass to fibrous adsorbent mass, the nondimensional temperature and the ratio of vessel length to fiber diameter. Fourier number for the completion times of adsorption processes were also correlated by Reynolds number, and the ratio of desorbed water vapor mass to fibrous adsorbent mass, the nondimensional temperature and the ratio of vessel length to fiber diameter.

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The main subject for enhancing automotive evaporator wet-fin-performances is to promote the draining of condensed water. The accurate and convenient apparatus estimating the fin performances has been developed. Through the measurement of corrugated multi-louvered fin performances and the visualization of condensed water draining by this apparatus, it was clarified that fin geometries, surface coating and evaporator installation were severely contributed to the efficiency of draining and fin performances.

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For experimental treatments of atomic clusters, a FT-ICR (Fourier Transform Ion Cyclotron Resonance) spectrometer with a direct injection supersonic cluster beam source was implemented. Newly designed ICR cell in 6 Tesla superconducting magnet was proved to give a high mass-resolution for positive and negative cluster ions. With this mass-spectrometer, pure carbon and metal-carbon binary clusters generated by the laser-vaporization supersonic expansion cluster-beam source were studied. A special cluster beam source condition was found where only C^_<60> was observed for pure carbon clusters. Furthermore, positive lanthanum-carbon, yttrium-carbon and scandium-carbon binary clusters showed only MC⁺_2n signal in the range of 36&le;2n&le;76 with strong magic numbers at MC⁺₄₄, MC⁺₅₀ and MC⁺₆₀. Characteristics of these small clusters were compared with results of molecular dynamics simulations.

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Prediction of light scattering is required to develop the optical measuring techniques for detecting the size and shape of an individual non-spherical particle. However, the applicability of well- known Lorentz-Mie theory is fairly limited and is unsuitable for this purpose. In this paper, we examine the feasibility of a direct solution method of Maxwell's electromagnetic wave equation for predicting the laser light scattering by a non-spherical object. It is confirmed that the Cartesian coordinate system is available for predicting light scattering, even if the shape of a scattering object is stepwise approximated based on the Cartesian coordinate system. That is, a complex coordinate system matched to the shape of a scattering object is not required. In addition, it is clarified that the electromagnetic field produced in the near field of a scattering object remarkably varies depending on its cross sectional shape even if the scattering patterns are almost same in the backward far field. This suggests that the estimation of multiple scattering effects in the optical particle sizing techniques should be conducted based on the near field scattering pattern. The method employed in this paper is suitable also for these purposes because this method can easily deal with a closely allocated group of scattering objects.

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Based upon a collisional and radiative process theory, and synthetic spectra for argon plasmas, the experimental method for spatial properties of Ar plasma jets was presented, and applied to diagnostics for micro Ar plasma jets for fine cutting. A plasma torch had a nozzle of 0.7 mm in diameter and a discharge length of 2 to 10 mm, and was operated with an arc current of 10 to 30 A. Data from a CCD image processor and Mach-Zehnder interferometer were dealt with an Abel transformation to obtain true spacial profiles of electron density and temperature, and heavy particle temperature. Electron temperature in the main flow was found to be about 12 000 to 13 500 K, electron density of an order of 10¹⁶ cm^-3, both increasing with an arc current. It was also found that heavy particle temperature was significantly lower than electron temperature in the nozzle exit region and increased to coincide with electron temperature downstream. Experimental relation of electron temperature and density could be approximated well by that calculated from steady-state collisional and radiative processes.

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Oxygen atoms play a very important role in atmospheric pressure chemical vapor deposition (CVD) processes for silicon oxide films using tetraethylorthosilicate (TEOS) and ozone. Efficient generation of active oxygen species including these oxygen atoms is realized by use of a square-pulsed silent discharge with very sharp rising and falling of applied voltage. In this study, nonequilibrium plasma chemical reactions by this discharge have been applied to a remote plasma CVD of silicon oxide films using TEOS and oxygen. And deposition characteristics of silicon oxide films by this method have been measured experimentally, and these have been compared with CVD characteristics using low frequency AC silent discharge. Futhermore, these have been compared with deposition characteristics of silicon oxide films using TEOS and ozone. As a result, it has been clarified that silicon oxide films with high quality of step coverage and high deposition rate of these films can be obtained by the remote plasma CVD using pulsed silent discharge.

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A new method is proposed to measure the viability of round cells compressed by two parallel plates which simulate ice crystals during freezing of cell suspension. The viability of prostate cancer cells (cell line ND-1, 20 μm in mean diameter) is evaluated at about 23°C with trypan blue dye exclusion assay. While most of the cells survive deformation in a gap of 11.4 μm, about half of the cells are destroyed when the gap size is reduced to 5.9 μm, i.e. 30% of its original diameter. If uniform expansion of cell membrane is assumed, this corresponds to 50% increase in the cell membrane surface area.

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A three-dimensional model for the combustion process and NO formation in a spark-ignition engine was established based on the submodel described for flame development. Computations carried out for different conditions in a natural-gas engine show a reasonable degree of reproduction of the entire combustion process. The spatial profile of combustion, the histories of flame temperature and the relations between flame temperature and NO formation are investigated to catch the information about the NO formation mechanism with special attention to the mixing of heat and mass in the combustion processes.

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Behavior of a spray combustion in a hot air was studied experimentally. A kerosene spray was injected from swirl atomizer into a hot air stream. The air temperature was controlled from room temperature to 1 100 K which was higher than the self-ignition temperature of a kerosene spray. Flame shape and temperature distribution were measured to characterize the spray combustion appeared in the hot air stream. Flow state around the spray was visualized by a Schlieren method to analyze the behavior of the air entrainment into the flame. Furthermore, Mie scattering from the spray droplets by irradiation of the laser beam was observed to visualize the spray concentration in a flame. As the result, ignition point was shifted to the upstream side with an increase of air temperature. When the air temperature became higher than 800 K, the blue flame appeared at the bottom portion of the flame. Penetration of the spray became shorter with an increase of air temperature. Spatial distribution of the spray which were not vaporized in a flame was strongly affected by the air temperature.

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Two-dimensional unsteady reactive flows are calculated to investigate the instability of premixed flames at high Lewis numbers and the formation of cellular flames due to inherent instability. We superimpose an infinitesimal disturbance on a stationary plane flame to obtain the relation between the growth rate and the wave number, i.e., the dispersion relation. We have positive growth rates at small wave numbers and the marginal wave number separating the stable/unstable range. As Lewis number increases, the growth rate decreases and the unstable range becomes narrower. Since there are positive growth rates, cellular flames appear at high Lewis numbers owing to inherent instability. To simulate the process of cellular-flame formation, we superimpose the disturbance with the peculiar wave number corresponding to the maximum growth rate. The disturbance on the flame is evolved, and eventually the cellular flame front is formed. With an increase in Lewis number, the spacing between cells becomes larger and the cell becomes deeper. In addition, the stationary cellular flame is obtained when the inlet-flow velocity is set to the flame velocity of the cellular flame because cells on the flame do not move laterally.

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A tubular flame burner with 150 kW has been developed and its combustion characteristics for propane have been investigated. The main results obtained are as follows: (1) A tubular flame with a large laminar flame area up to 0.3 m² can be stabilized. (2) The equivalence ratio Ф at limit is about 0.55, which yields lean combustion. (3) The flame diameter and the flame length take their minimum and maximum values around Ф=1, respectively. (4) The wall temperature is kept around the unburned gas temperature, yielding long operation hours. (5) The burned gas temperature in the combustion tube is uniform in the axial direction. (6) The volumetric burning rate is equal to the total mixture volume flow rate within 30% disagreement, and hence, the burner length can be determined by using this relation.

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The multidimensional engine simulation code. FREC-3D(CI), has been used to elucidate the effects of injection rate and split injection on diesel combustion, NO, and soot emissions. The combustion submodel has been updated, including the ignition submodel previously based on a one-step global mechanism. In-cylinder NO and soot formations were predicted by a Zeldovich mechanism with a partial equilibrium assumption and Morel's soot formation with an oxidation submodel, respectively. In a result, computations give good agreement between measured and predicted trends of in-cylinder pressure, and rate of heat release, and a trade-off relationship between NO and soot emissions at pilot injection with high pressure injection. Computations also show that a high turbulence kinetic energy caused by a higher initial combustion is retained at the late combustion stage after fuel injection, and promotes the soot oxidation process. Predictions made with split injection suggest that a combination of high pressure injection in conjunction with a short period in second pulse is effective to reduce soot emission.

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