Experimental results related to the behavior of HexMC^® angle beams subjected to pure bending are obtained and compared with theory. The beams were produced using compression molding. Material properties inferred from coupon-level tests were used to predict the elastic and buckling behavior of the angle beams.

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The fuel jet velocity at the extinction limit of a jet diffusion flame can be as large as that at the blowoff limit under microflame conditions, requiring detailed understanding of extinction mechanism. This paper first discusses a simple theory to describe the extinction mechanism of jet diffusion microflame. An activation-energy asymptotics technique is adopted with the use of constant-density approximation to predict the extinction limit. Results of experiments for different burner diameters are then presented to compare theoretical predictions with experimental observations.

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We produced high-density solid biomass (hereafter called Bio-coke) from broccoli, dead cherry tree leaves, and seed of mango based on our patent (PAT.-No.4088933) as one of the utilization methods of various unutilized biomass. The compressive strength of each kind of Bio-coke under room temperature was measured with a compression testing machine. The experimental results showed that the ultimate strength was related to the carbon content of broccoli, seed of mango, and dead cherry tree leaves, and the relations were close to linear.

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The aim of this study is to investigate an unsteady behavior of a droplet impacting on a horizontal plate with poor wettability. Visualization techniques employed in this study include Computational Fluid Dynamics (CFD) and experimental one using a high-speed camera. The contact angle of the plate is varied by coating a water repellent material on its surface. This paper presents snapshots of bouncing motion of a droplet, the deformation rate at the impact on the plate, the coefficient of restitution, and flow in the droplet.

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Effect of repeatedly imposed acceleration on transition to turbulence in transient circular pipe flow has been investigated experimentally together with the laminar analytical solution. The acceleration pattern in the present study is a combination of two constant accelerations from rest in which the second acceleration is larger than the first one. The axisymmetric Navier-Stokes equations are solved for the present target flow to compare the experimental results before the appearance of turbulence. As a result, the present impositions of the repeated acceleration on the pipe flow cannot distinctly suppress transition to turbulence within the present adopted experimental conditions. However, the laminar solution obtained for the accelerating pipe flow was found to be valid for the present target flow until transition to turbulence and, after the turbulence appeared, the axial velocity was approximated with the 1/nth power law for a steady flow.

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Air leakage from a thin radial gap between the flange of a circular pipe and a flat disk is experimentally studied. The effects of the wettabilities of the flange and the disk on the flow coefficient are examined in detail. The height of the gap ranges from about 50 μm to 500 μm. The surface roughness of the gap is varied by coating two types of repellents. The flow coefficient relating the flow rate to the pressure drop of air passing through the gap is experimentally determined and compared with both an analytically obtained equation and an empirical equation proposed so far. As the prediction of the present data by the previously proposed equations is not satisfactory, an empirical equation is newly proposed.

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Water model experiments were performed to develop a novel agitation method for the desulfurization process. Specifically, we focused on mixing time of a cylindrical bath agitated by gas injection from a multi-hole nozzle. The mixing time was determined by measuring the time-dependent electrical conductivity of a liquid containing a KCl aqueous solution. The mixing time was found to be closely related to the immersion depth of the nozzle. An empirical equation was proposed for the mixing time.

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The near-field acoustic characteristics of underexpanded jets from notched nozzles have been investigated via an optical wave microphone. This laser-based microphone not only leaves jet flow unobstructed, but it also enables us to measure the simultaneous sound propagation in both vertical and horizontal directions. As a result, through the observation of the real time fluctuation of jet noise, we came to the conclusion that the screech tone from 2-notched nozzle is propagated solely on the unnotched side with sound speed, and the strongest source of noise can be moved when the notch number is changed.

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An experimental investigation is carried out on air-water two-phase flow through a plate orifice in a millimeter-scale rectangular channel. The width of the channel is kept constant at 50 mm and the height is varied from 0.19 mm to 2.00 mm. The contraction ratio of the orifice is varied from 0.04 to 0.4, and the thickness of the orifice also is allowed to vary over a wide range. The flow patterns upstream and downstream of the orifice are observed with a high-speed camera and by visual inspection. The conditions for occurrence of the observed flow patterns are presented on a flow pattern map. The velocity of the leading edge of a bubble, representing the bubble velocity, is deduced from the camera images. In the upstream part of the test section the bubble velocity is approximated by the sum of the superficial velocities of air and water. A correlation is proposed for the maximum bubble velocity in the whole test section as a function of the two superficial velocities and the contraction ratio.

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The severe problem of the disposal of various wastes continue to increase, one of which is waste concrete. In relation to global warming, reducing the generation and fixation of CO₂ gas must also be solved. This paper experimentally examines an efficient recycling system to reuse the sand in waste concrete whose mean size is about 0.3mm. We found that the liquation of Ca²⁺ with waste concrete in a hydrochloric acid water solution of pH≈2.5 is optimum. Next, we show a new efficient CO₂ gas fixation method by the reaction of carbonic acid with a micro bubble CO₂ gas jet flow. Finally, a new process system to efficiently recycle waste concrete and to improve CO₂ fixation and its performance is examined.

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Experiments on flow pattern and flow boiling heat transfer of CO₂ and CO₂-oil mixtures in horizontal small diameter smooth and micro-fin tubes were carried out. The test smooth tube is a stainless steel tube, 2.0mm in inner diameter and 1m in length. And the test micro-fin tube is an inner grooved copper tube, 1.95mm in mean inner diameter and 1 m in length. Experiments were conducted at mass velocities from 380 to 1500 kg/(m²s), a saturation temperature of 10°C, heat fluxes from 10 to 43.3 kW/m². The flow patterns in both the tubes were observed and the results were compared with the flow pattern map proposed by Cheng et al. for smooth tubes. And the measured local heat transfer coefficients for the smooth and micro-fin tubes were compared with those calculated from the prediction correlations proposed by Cheng et al. for smooth tubes. As the results, the flow patterns in both the tubes correspond well with the flow pattern map. On flow boiling heat transfer of pure CO₂, the prediction model agrees well with the experimental data of the smooth tube, and the measured local heat transfer coefficients of the micro-fin tube are about 31% higher than those of the smooth tube. For CO₂-oil mixtures, the measured local heat transfer coefficients of both the smooth and micro-fin tubes are much lower than those of pure CO₂. The dryout inception qualities of the micro-fin tube increase with the increase in mass velocities, while those of the smooth tube decrease with the increase in mass velocities. The dryout inception qualities of the micro-fin tube are much higher than those of the smooth tube.

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Recently, an enough entrance region for a flowmeter cannot be kept in a compact system including fluid machines. In order to know the possibility of such a compact design, the error of an ultrasonic flowmeter was investigated experimentally. In the experiment, the velocity fields downstream of an elbow were measured by PIV and the error was estimated based on the obtained velocity distribution. The error distribution along the pipe and the dependence of the measurement line were obtained. Furthermore, a flow straightener effect was examined.

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The gas-liquid flow distributions in multi-pass upward parallel channels and pressure inside headers were examined experimentally. Attention was directed to the influences of the back-pressure condition and of the flow-inlet condition on the gas-liquid distributions to the branches. Experiments were conducted in an isothermal air-water flow system. The influence of the backpressure condition changed depending on the flow-inlet condition. In the mist-flow inlet, the water distribution uniformity was improved. The pressure in headers was nearly uniform.

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In this study, we investigated the effects of steam on the reduction in fat and/or water content during the heating of foods. Experiments were performed at 250°C with steam and without steam by using three types of heating equipments; the equipments had different heat transfer coefficients and rates of increase of gas humidity. Sausage and raw pork pate were used as model sample materials. During roasting with steam, the amounts of weight loss and fat loss were greater in the raw pork pate than in the sausage because the amount of protein shrinkage in the pork pate was greater than that in the sausage.

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Discharging gas jets in low-pressure conditions are interesting and important phenomena from an engineering point of view. For example they relate to the gas jet thruster for attitude control of artificial satellite, and gas purging method in the semiconductor technology. The jets, however, deform to the complicated shapes by interacting with solid walls. This paper deals with visualization experiments on the interacting jet and plane wall by applying LIF (Laser Induced Fluorescence) method using an Ar-ion laser. We have obtained a series of jet-wall interacting images at various distances.

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A standing wave with a peak line toward downstream appears on the surface of a liquid film flowing around a horizontal circular cylinder. The amplitude of the wave grows in the downward direction and finally a part of the wave separates from the film. A theoretical model was proposed to explain the physical mechanism of separation. The wave peak would separate when the resultant of the centrifugal force, gravitational force, surface tension and negative pressure acting on the wave root is not sufficient to supply the flow rate necessary to maintain the wave amplification. The points of separation on the cylinder were calculated theoretically for three kinds of test liquids, i.e., water, ethanol and glycerin solutions. The results agree with those from experiments for various flow rates of the film flow.

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Micro-jet diffusion flames, formed by a minute burner of a few hundreds or a few tens micrometer inner diameter, should be interesting and useful, partly because they resemble micro-gravity flames and partly because they provide some insight into the mixing and chemical kinetic processes occurring in turbulent diffusion flames. The aim of the present experiment is to collect preliminary information on the characteristics and experimental techniques of micro-jet flames. Attention was paid to the effect of Reynolds number (Re) at the burner exit, and the range of Reynolds number that a stable flame could be formed was determined. CH-band images were recorded by direct photography, and compared with laser shadowgraph images.

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Disintegration process of aqueous surfactant solutions injected from a fan spray nozzle has been clarified. Adsorption of surfactant molecules on the liquid surface causes time-dependent surface tension referred to as "dynamic surface tension". Therefore, when a new liquid surface is formed, surface tension decreases from the value of solvent to equilibrium value with time. This relaxation time of surface tension can be critical for the disintegration process of a liquid sheet that breaks up in comparable timescale. In this study, poly(oxyethylene)(10)octylphenyl ether was used as the surfactant, and the dynamic surface tension of the surfactant solution depending on concentration was measured by oscillating jet method. The break-up length of the liquid sheet and the amplitude of flapping waves inducing the disintegration were also measured by photography and laser induced fluorescence (LIF) method, respectively. The addition of the surfactant decreased the relaxation time of surface tension, and promoted the growth of the wave. However, break-up length increases with surfactant concentration. This discrepancy may be due to surface-stabilizing effect by the surfactant molecules, which is usually seen in a soap film.

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For future work on the turbulent premixed flame propagation in high intensity turbulent flow, we measured the turbulence characteristics in the Taylor-Couette flow apparatus between two counter rotating concentric cylinders. The turbulence characteristics such as the integral, the Taylor's micro, and the Kolmogorov scales, intensities and power spectral density functions are obtained from the velocity fluctuations of the radial and circumferential components in the annulus measured by hotwire anemometry.
The intensity of the velocity fluctuation of the circumferential component linearly increased as Reynolds number Re_Ω increased. At the highest Reynolds number (Re_Ω = 7,200) in the present work, the intensity is more than two times as large as the lean laminar flame velocity for a methane-air mixture (0.12m/s), which corresponds to the regime of corrugated flamelets. Our results suggest that the Taylor-Couette flow apparatus is useful to study the premixed-flame propagation in high intensity turbulent flow.

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A water disinfection treatment using ozone microbubbles generated by a hollow ultrasonic horn was developed, and its disinfection ability to Escherichia coli in water was investigated. The treatment using ozone microbubbles generated by the hollow ultrasonic horn can completely sterilize within half the time required in a treatment using bubbles generated by a disperser. These results revealed that the disinfection treatment using ozone microbubbles generated by the hollow ultrasonic horn has high mass transfer efficiency and disinfection ability.

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This paper presents a method that uses digital in-line holography for the simultaneous visualization of stirring rods and stirred tank flow. This is achieved by dispersing two types of tracer particles, having different diameters, in the tank flow and rods, at a Reynolds number of 2810. By using this method, the three-dimensional velocities of both the tank flow and stirring rods can be individually visualized. Additionally, the cores of vortex tubes are visualized from the differences in specific gravity and refractive index between ethanol and an aqueous solution of sodium iodide.

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A nuclear fuel spacer is one of the components of a fuel rod bundle and its role is to maintain an appropriate rod-to-rod clearance. Since the fuel spacer influences liquid film flow on fuel rods in a fuel rod bundle of a Boiling Water Reactor(BWR)'s core, its specification has a strong effect on thermal hydraulics such as critical power and pressure drop. Though the spacers have been developed through empirical modifications, a large amount of test data has still been required for optimum design of the spacer. It is, therefore, an important subject to develop a model of the spacer based on the flow mechanism corresponding to shape changes in the spacer design of BWR fuel bundles. In the meantime it is considered that the droplet deposition on the fuel rod is enhanced downstream of the fuel spacer because a flow velocity distribution split by the spacer is recovered into a normal velocity distribution or profile. In the case, it is considered that droplets would be moved with the gas flow occurring in the process of a change from the higher velocity in the core to the lower velocity. In our previous work, a spacer model was proposed on the basis of two dimensional experimental data with a simple rectangular channel using air and water as working fluids with various thickness of test pieces and gap clearances. However, the channel configuration of an actual flow in the fuel bundle forms three dimensional shape.
In this study, the effect of spacer geometry on a gas velocity downstream of the spacer is investigated experimentally in the atmosphere with the use of an circular channel which has a similar hydraulic diameter to an actual fuel bundle. The model equation, which shows a lateral velocity profile based on rectangular channel data, is compared with circular channel data, and shows a good agreement with circular data by introducing a velocity reduction term as a three-dimensional effect.

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When a high-speed train enters a long tunnel, compression wave is generated in front of the train. This compression wave propagates in the tunnel at the speed of sound. In recent years, the running speed of train is increasing, and this problem of the tunnel pressure wave may occur by the conventional limited express. This paper deals with the pressure wave formation by the experiment using an apparatus with diaphragmless driver acceleration, and small train nose models of limited express in combination with a short tunnel and some station models. We have obtained pressure waveform data and discussed.

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Quantitative image measurement of the flow fields in convective heat transfer is of great importance for the optimum energy consumption problems. In the natural and forced convection phenomena in fluids, the complexity of the flow field prevents us from detailed three-dimensional (3D) experimental analysis in steady /unsteady dynamics of the fluids, which have locally different density values. This paper deals with application of color-stripe background oriented schlieren (CSBOS) and Computed Tomography (CT) method to the quantitative measurement of natural heat convection.

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A laser tagging method by photochromic dye was used to easily visualize detailed flow structures of creeping flow and liquid film jet. Excimer laser (248 nm) and Nd:YAG laser (355nm) were used to form dye traces in the flow tests and then observed by using a video camera. From the movement of the dye traces, velocity vector field was measured. Vorticity and divergence of velocity vector field were also calculated. As a result, it was confirmed that the laser tagging method by photochromic dye easily enabled the visualization of both flow tests.

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In this report the novel and quantitative measurement technique of the image distortion related to the density gradient around an asymmetric cone model using colored-grid background oriented schlieren (CGBOS) method is presented. The CGBOS method enables us to obtain two-dimensional quantitative integrated distribution data of refractive index gradient around a test model in supersonic flow by calculating the distortion of the background image. We try to reconstruct the three-dimensional density information from CGBOS technique and Computed Tomography technique.

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The pressure profile and particle circulation rate in a fluidized bed gasifier with triple-beds and dual circulation were clarified by operating a cold model, which is the capacity of 10kg/d. As a result, the operation of the gasifier was stable. The predicted pressure profile in the gasifier qualitatively corresponded to the measured pressure profile. The particle circulation rate increased with increasing pressure drop in the riser, which is the pressure difference between riser and cyclone inlet.

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Impedance spectroscopy (IS) is a measure of the electrical response of a system, and analysis of the response to yield useful information about the different properties of the system. In the present work, its application for the determination of concentration of the particles in the flowing liquid is presented. Experimental results are presented for polysterine particles floated in the water. Additionally, the method has potential to determine the composition of the liquid. Experimental results with the mixture of milk and yougurt are presented. Moreover, simulation results with the blood cells floating in the suspending plasma are presented to study the application of the methodology to monitor the clotting of the blood.

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In this study, we investigated the effects of through-flow (one directional, single phase) on Taylor-Couette vortex by measuring the dynamic characteristics with an Ultrasonic Velocity Profiler (UVP). Then, we have planned to investigate the characteristics of Taylor-Couette vortex flow with counter flow (two directional, two phase). As a first step, we observed the flow patterns of dispersed phase in Taylor-Couette vortex by dyeing the phase. In addition, for the quantitative measurement of the flow field of dispersed phase, we evaluated the applicability of UVP.

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A method for determining stresses from isopachic contours obtained by interferometry or thermoelasticity is proposed in this paper. A Poisson equation that represents the relationship between the sum of principal stresses and an Airy stress function is solved using a finite element method. Therefore, the distribution of the Airy stress function can be obtained from the measured isopachic contours. Then, the stresses are obtained from the Airy stress function. Boundary conditions are required for solving the Poisson equation. In the present stage, tractions along the boundary are used for obtaining the Neumann boundary condition. Results of simulation and experiment indicate that stress components can be obtained from isopachics by the proposed method.

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This paper deals with the strength and failure prediction as well as the reliability issues of adhesive joints of brittle epoxy bonding two dissimilar adherends. The effects of bond thickness and scarf angle upon the strength of such joints are also addressed. Three kinds of adhesive joints, i.e., butt, scarf and shear joints are considered. It is found that the strength prediction of various adhesive joints can be done by establishing the interface corner toughness, Hc parameter. Weibull modulus is suitable to define the reliability of adhesive joints. The scarf joint of 45° is identified to be preferable since it satisfies both outstanding load-bearing performance and tolerable reliability. Hence, both applications of Hc parameter and Weibull statistical method allow the strength and failure predictions of adhesive joints with fairly improved reliability.

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Glass powder reinforced epoxy was used in the fields of plastic sealing of semiconductor devices. In such environment, the materials were exposed in the high temperature, and the visco-elastic behavior must occur in the materials. However, there are few reports about these materials focused on visco-elasticity. Therefore, the analysis of visco-elastic behavior was an important issue to be taken in account. In this study, the stress relaxation behavior and dynamic mechanical analysis of epoxy composites filled with different amounts of glass powder were investigated. On the dynamic mechanical analysis, the glass transition temperature decreased with the increment of the amount of glass powder contents. And the viscosity at high temperature also decreased when the contents were augmented. On the stress relaxation test, master curves of stress relaxation were obtained, and the time-temperature superposition principles was ascertained. The slopes of time-temperature shift factors were changed depending on the amount of glass powder. Therefore, the time-temperature shift factors were calculated by using the relationship between the slopes of the time-temperature shift factors and the amounts of glass powder. The effect of amounts of glass powder on stress relaxation was also investigated. When the amount of glass powder increased, then the stress relaxation curves shifted to short time side. Comparing the master curves of stress relaxation with the different amount of glass powder, it is understood that the stress relaxation behavior of each material is similar. The effect of glass powder contents on stress relaxation behavior showing the effect of reinforcement and heat resistance is also discussed.

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We studied the fracture behavior of a glassy polymer, epoxy resin, under the effect of static and impact tensile loading using single-edge-cracked specimens. The static and dynamic loads were determined using a load cell and a piezo sensor, respectively, and the displacement of the specimen was measured using a high-speed extensometer. From the load-displacement diagram, the external work (U_ex) applied to the specimen was used to evaluate the elastic energy (E_e) and nonelastic energy (E_n) due to viscoelastic and plastic deformation, and the fracture energy (E_f) for creating a new fracture surface (A_s). The energy release rate was then estimated using G_f = E_f/A_s, and the values of G_f were correlated with the fracture load (P_c). The result indicated that although G_f increased with P_c for both tests, the impact test showed much lower values than the static test.

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Two y-cut z-propagation (Y-Z) LiNbO₃ (LN) electro-optic (EO) crystals have been considered as transverse phase modulators for the fast birefringence measurement. To obtain birefringent parameters from modulated polarization status, the LN crystals were driven at different frequencies. This work aims to analyze the effect of parameters such as modulation amplitude and the order of Bessel functions on decision of the frequency ratio of drivers. According to our theoretical analysis, it was found that the modulation amplitude greatly influences the selection of the driving frequency.

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The high strain-rate compressive stress-strain properties for bulk specimens of a two-part epoxy structural adhesive for general purpose industrial applications are determined on the standard split Hopkinson pressure bar at room temperature. The complete compressive stress-strain data including unloading process are obtained over a wide range of strain rates from 10^-3 to 10³/s. The effects of strain rate on the initial (secant) modulus, flow stress, dissipation energy and hysteresis loss ratio are discussed. The experimental results show that the bulk epoxy adhesive distinctively exhibits dynamic viscoelastic behavior like polymers.

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The effect of welding speed on the tensile properties and fracture behavior of friction stir welded AA6061-T6 joints was examined. AA6061-T6 sheets of 4.95 mm in thickness were friction stir welded in the butt joint configuration. The friction stir welding (or FSW) parameters were varied by altering a welding (or traverse) speed of a cylindrical tool, keeping its rotational speed constant. Dumbbell-shaped specimens machined from the base material and the FS welded joints were used in the tension tests. The Ramberg-Osgood relationship was used to describe the true tensile stress-strain curves. It is shown that the FS welded joints exhibit reduced strength and ductility compared with the base material. This reduction is discussed from a microstructural point of view.

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A new container consisting of a plastic case and a liquid-packaging bag with a simple pouring lip for liquid food products, such as soy sauce, has been developed in recent years. The new container is capable of delaying the discoloration and decay of liquid food products, although the reason for this remains to be determined. In this study, to determine the above reason, soy sauce in droplets, at the end of glass channels made to simulate the pouring lip and at the end of actual pouring lips was observed. Results indicated that salt crystals are present in the droplets and at the ends of the channels and the pouring lips.

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This study deals with the mechanical properties of two kinds of structural sintered steels under a wide range of strain rate between 10^-4 and 10³s^-1. The split-Hopkinson pressure bar (SHPB) technique was used for dynamic tensile tests at the strain rates greater than 10²s^-1. The stress-strain relations were experimentally determined, and the tensile strength has been mainly discussed with respect to strain rate and relative density.

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High polymers or composite materials with lightness and formability have widely been used in various industries. It is well known that these materials show the viscoelastic behavior; the deformation remarkably depends on the time or strain rate. It is, therefore, very important to understand the dynamic behavior technologically. To this end, the split Hopkinson pressure bar techniques using polymeric materials (polymeric SHPB technique) have been used as a method of evaluating the compressive impact characteristics of various viscoelastic materials. However, the accuracy of the method depends on the specimen geometry and mechanical properties of test materials. In this research, therefore, a method of calculating the experimental strain waveform obtained by the polymeric SHPB technique is proposed. The calculations of reflection and transmission at interfaces are considered based on the one-dimensional theory in the frequency domain. The amplitude of reflected strain pulse and the stresses at both interfaces of the specimen are analyzed by changing the mechanical impedance of the specimen. The uniform deformation within the specimen is required in the polymeric SHPB technique. Moreover, the appropriate amplitude of the reflected and the transmitted strain pulses should be measured. Next, polymeric SHPB tests are carried out by using some specimens. The complex compliances of the specimens, which are the ratio of the strain to stress in the frequency domain, are determined, and a mechanical model are identified. It is shown that the actual polymeric SHPB tests should be performed based on the appropriate impedance matching between the specimen and input/output bars studied by the numerical experiments.

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The residual stress analyses of Al/Mg compounds were done using the hole drilling method with strain gage rosettes. The evaluation method used is based on an FE model, which includes the formation of the residual stress state by the cooling process of the coextruded rod with different coefficients of thermal expansion of the two basic materials. Because of the special stress state, it can be shown that the strain distribution versus the hole depth depends on the specimen height. The results in radia direction at the interface are low tensile stresses.

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This paper deals with the applicability of the near infrared (NIR) spectroscopy to quantitative measurement of the water content in human articular cartilage using gelatin model. We developed the device using NIR light at a wave length of 970nm, and investigated whether or not the device was useful for the measurement of the water content in articular cartilage. The gelatin was used as materials for the specimens with single, two- and three-layers. The absorbance defined as the intensity ratio between emitting and receiving NIR lights, the variation of receiving light intensity with the water content, and that with the distance between two probes of the light source and sensor were measured. The absorbance increased with increasing water content and with increasing probe distance (R²=0.86∼0.91). In the layered specimens, the light was supposed to pass through the surface layer and then reach the adjacent layer. These results showed that the device was useful for the measurement of the water content in the single and layered specimens. This study suggested that the device developed in this study have some possibilities of acquiring the quantitative data of water content at any point from the surface of articular cartilage.

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A combination of finite element modeling (FEM) and artificial neural network (ANN) is employed to estimate the surface pressure of flapping wing micro air vehicle. The ANN training patterns are prepared by varying the surface pressure distributions and calculating their associated strains through FEM. Through the well-trained network, the surface pressure can be estimated instantly by the strains measured during flapping. The maximum flapping frequency that represents the strength of flapping wings is then predicted using maximum strain criterion, in which the critical strain was measured using the standard ASTM specimens. The relation between the flapping frequencies and strains is a curve fitted by the data measured under lower and safer flapping frequencies.

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The purpose of this research is to evaluate the effects of surface qualities on crack initiation life as well as fatigue life. The practical method presented by the authors for the detection of fatigue crack initiation using an ion-sputtered film was used to divide the fatigue life into the fatigue crack initiation life and the fatigue crack growth life in three-point bending fatigue tests. Normalized and case-carburized test pieces with crowned round notches were used in the tests where the development of fatigue was monitored from fatigue crack initiation to breakage. The normalized test pieces have different surface roughnesses and the case-carburized test pieces have different surface microstructures on the notch surfaces. The changes in crack initiation life and fatigue life owing to the notch surface qualities were investigated. From the obtained results, the following conclusions were drawn: the fatigue crack initiation life is increased several times by decreasing the surface roughness Ra from 1.27μm to 0.03μm for a normalized middle carbon steel; removal of the non-martensitic layer formed during case-carburized treatment leads to a marked increase in fatigue strength.

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The present work reports surface segregation in polycrystalline yttria-stabilized zirconia (cubic) including 10 mol% Y₂O₃ (10YSZ). The 10YSZ specimen was annealed in the range 1073 K - 1673 K in the gas phase of controlled oxygen activity. The segregation-induced intensity profiles of ⁸⁹Y, ²⁸Si, and ⁹⁰Zr were measured using secondary ion mass spectrometry (SIMS). The data obtained show that (i) annealing of 10YSZ results in the formation of segregationinduced concentration gradients of ⁸⁹Y, ²⁸Si, and (ii) segregation-induced profiles depend on oxygen activity.

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This study aims to investigate the physical and chemical transformation of agricultural wastes during gas phase reactions with applications in electric arc furnaces steelmaking. Palm shell and coconut shell blended in different proportions with cokes were combusted in a drop tube furnace and were pyrolyzed in a thermogravimetric analyser at 1473 K. Coke/agricultural blends indicated higher combustion efficiencies. Scanning electron microscopy showed that the pore structure in the char particle from agricultural blends became lost of cell lumen and higher surface area, supporting the higher combustion efficiency in comparison with cokes alone.

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A fabrication method of a nanoporous anodic alumina film on the inner wall of a microchannel was investigated. An open microchannel was produced by a powder-metallurgical microchanneling process using Al as a body metal and Zn as a sacrificial-core metal. However, the cross-sectional area of the microchannel was larger than that of the sacrificial core; it increased as the compacting pressure increased. The nanoporous alumina film was produced by anodic oxidation of the inner wall of the microchannel.

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We examine a concept and fabrication method of a microchannel-type transpiration-cooling device consisting of thermally resistant metals. The device consists of open-porous Ni-Al alloys and contains microchannel networks. Cooling water is supplied from a tank to every corner of the device through the microchannel networks, and then it seeps out to be vaporized absorbing the latent heat. The porous body of the device and the microchannel are produced by a powder-metallurgical microchanneling process using a sacrificial core.

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We investigate alkali leaching of Ni-Al alloy microchannel lining layers to produce a metallic microreactor for high-temperature catalytic reactions. The microchannels and the lining layers were produced by a powder-metallurgical microchanneling process with Ni powder and Al wires. We explored the conditions for the process to produce an Al₃Ni or Al₃Ni₂ lining layer. The Al concentration of the lining layers was successfully decreased by alkali leaching.

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A Cu-Zn alloy microchannel lining layer was fabricated by a powder-metallurgical process using Cu powder and Zn wire. The effects of the dealloying treatment on the composition and structure of the lining layer were investigated. The lining layer became more porous and dezinced as the dealloying time increased. In the case of long-time dealloying, Zn-based corrosion products precipitated. These results indicated the possibility of the control of the structure and composition of the inner wall of the microchannel.

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High-temperature oxidation of the inner wall of a microchannel has been examined in order to fabricate an oxide coating for catalyst supporting. The microchannel was produced in a nickel body by a powder metallurgical microchanneling process, and it was lined with a NiAl intermetallic alloy layer. By high-temperature oxidation, an alumina scale was fabricated on the surface of the microchannel lining layer. In some cases, the alumina scale had a needle-like structure on its surface.

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