This paper is two dimensional numerical simulations of solid-liquid flow in straight micro-channel. It is shown that mixing effect of particle by applying AC electric field. Mixing is one of the important operations of μ-TAS. However, flow in micro-channel is laminar flow because of low Reynolds number. Therefore, mixing in micro-channel is difficult. Electric potential is applied at four channel wall electrode. Particle mixing is encouraged by interaction of forced convection and electro-osmotic flow. Mixing characteristics of particle is depends on frequency of AC electric field.

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To improve energy efficiency with reduction of cost in polymer electrolyte fuel cells (PEFCs), optimization of PEFC electrode structure with sufficient oxygen, proton and electro supply is of great importance. Visualization of current path in catalyst layer (CLs) gives us a fruitful insight to understand the structure and mechanism of electrodes. In this study, PEFC electrodes were investigated using atomic force microscopy (AFM). We measured modeled catalyst layers deposited on stainless substrate using current sensing AFM to investigate distribution of electric current across the CLs. The conductive area decreased with ionomer content and current percolation limit was 75-80wt.% ionomer content. We also conducted AFM visualization of cross section of electrodes that was prepared by cross sectional polishing (CP) to investigate nano-scale structure of catalyst layer. It was shown that the carbon agglomerates were 35-70nm in diameter.

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Liquid water in cathode catalyst layers (CLs) in polymer electrolyte membrane fuel cells (PEMFCs) affects performance of PEMFCs. To evaluate an effect of liquid water, we developed a calculation method with Lattice Boltzmann method (LBM) and pore network modeling (PNM). LBM was used to calculate oxygen, proton and electron transport in a model CLs while PNM was used to obtain liquid water transport. We successfully demonstrated this novel calculation method useful to investigate liquid water behaviors and its effect on overall cell performance in the cathode catalyst layer in PEMFC.

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We investigated the relationship between cell voltage and the differential pressure through cathode channel, with the three different cells which have different channel-pattern on each. In the cases of straight 1-channel and serpentine 1-channel, the cell voltage was well synchronized with differential pressure. In case of parallel 3-channel, however, the synchronization did not occurred clearly. To evaluate the relationship quantitatively, we calculated the cross correlation between cell voltage and differential pressure. It figured out that the straight 1-channel and serpentine 1-channel cells showed a good correlation of -0.5 and that parallel 3-channel indicated a weak correlation of -0.3 under flooding condition. We considered the reason to give the correlation difference between different channel-pattern cells with a visualization study.

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Temporal variation and spatial distribution of interfacial mass-transfer rate in the cathode side gas diffusion layer (GDL) of a proton exchange membrane fuel cell during start-up were numerically investigated. For this purpose, a 3D transient two-phase nonisothermal model was used. A nonequilibrium evaporation-condensation interfacial mass-transfer rate is incorporated in the model, which enables us to take supersaturation and subsaturation into consideration. This helps us to investigate the most significant contribution of the phase-change rate to the transient response and thermal behavior of the cell.

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Adsorption characteristics of oxygen and sulfur atoms on Pt catalyst is important to consider the performance degradation of PEFCs. DFT calculation of O and S atoms on Pt surface is carried out. Preferred adsorption site for O and S atoms are discussed. The results show higher preference of S adsorption than O is suggested.

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Potential distribution in the electrolyte membrane in the MEA of PEFC has been measured in order to help understand a recently suggested membrane degradation mechanism caused by Pt band. A thin metallic probe, Pt, is inserted in membrane to measure the potential distribution. The potential in the membrane at a certain position are measured under several experimental conditions, for example, cathode gas oxygen concentration, cell current density and so forth. As a result, it is found that the potential are influenced by several experimental conditions.

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The present paper describes dynamic analysis of the system with a solid oxide fuel cell (SOFC). The present numerical analysis focuses on control scheme of the SOFC system for power output control by operating current density. Feedback circuit was assumed to be adopted within the present SOFC system. Proportional (P) controller and Proportional-integral (PI) controller were adopted to condition the current density in order to obtain the required power output in DC, and then their results were compared. Consequently, both of P and PI controllers can be adopted to operation of the SOFC system for the power output control scheme.

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This study focuses on the development of one-dimensional simulation model for the co- and counter-flow types of direct internal reforming planar SOFC to be implemented in a system analysis. The model is capable of capturing the distributions of the local temperature, concentration and current density in streamwise direction as well as performing exergy analysis. With higher accuracy compared to a zero-dimensional model often employed in a system analysis, phenomena in the anode and cathode channels are investigated. The study shows that co-flow configuration is more favorable for cogeneration system or hybrid operation.

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Microstructural parameters of SOFC porous anode are quantified with two different methods: random walk diffusion simulation and the concept of contiguity. The concept of contiguity is a conventional porous model which estimates a 3D porous structure based on 2D cross-sectional images. We try to check the validity of the model by comparing it with the direct quantification method based on a real 3D structure. It is found that concept of contiguity can be applied to the phase with relatively high volume fraction. If volume fraction is lower than the percolation threshold, it tends to underestimate the complexity of the phase.

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Microwave sintering with selective susceptor and spacer has been proved to be an effective and facile method in the manufacturing of anode support solid oxide fuel cell (1). Two anode support SOFCs were fabricated by using microwave sintering and thermal sintering techniques, separately. The performances of the two cells were measured and compared in a temperature range of 700℃ to 800℃. The microstructures of the two cells after the measurements were compared qualitatively based on SEM images. FIB-SEM technique was used to reconstruct the 3-D microstructure of both anode and cathode. The quantitative comparison of 3-D reconstructions shows the advantages of using microwave in both anode and cathode sintering processes.

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Pure oxygen combustion has been attempted with using a rapidly-mixed type tubular flame burner. Results show that tubular flame combustion can be obtained with oxygen molar concentrations of up to about 80% in the oxygen/nitrogen mixtures, above which very intense vibratory combustion occurs. Detailed observation shows that a diffusion flame is formed between the fuel and oxidant streams at the exits of the fuel slits, which prevents mixing fuel with oxygen, followed by violent turbulent combustion downstream the slits. Suppression of formation of the diffusion flame is indispensable for pure oxygen tubular flame combustion.

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The effects of non-thermal plasma on characteristics of soot and NOx production in a diffusion flame were examined. The plasma reactor has wire-cylinder-type electrode with AC power supply operated at 40Hz. The flame length and the yellow luminosity by the radiation of soot particles are significantly decreased due to generation of the ionic wind as the applied voltage is increased. The mass density of soot is influenced appreciably by the non-thermal plasma, while NOx production is not influenced much by applied voltage.

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Multiphase combustion process of a micro PET (polyethylene terephthalate) resin particle is examined under different heating gas velocities. At higher velocity conditions, thermal decomposition of PET and flash gasification of the decomposed products are prompted near the particle surface, so that luminous flame is formed at an earlier stage of the multiphase process. On the other hand, at lower velocity conditions, duration time of the flame is shortened in spite of longer ignition delay and particle lifetime. This is probably because that partially premixed combustion takes place due to internal bubbling of the particle and resultant abrupt discharge of the flammable gas products.

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The focus of this research is placed on spatio-temporal evolution of vorticity produced by baroclinic torque and buoyancy in a density boundary layer between burnt gas of two-dimensional premixed laminar flame and side air flow. PIV and discrete vortex simulation of Lagrangian transport element method are carried out. As a result, it is found that accumulated vorticity due to buoyancy in a density boundary layer leads to roll-up of large-scale vortical structure in downstream region. Then, it induces acceleration of a density boundary region through kinetic pressure, resulting in secondary generation of baroclinic torque.

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This paper describes the experimentally results of flame spread test along a thermally thin combustible solids with a non-combustible zone exist. Probability of spreading flame across the non-combustible zone varies by the width of non-combustible zone. The maximum width of the spreading flame across noncombustible zone was larger than the preheating width. This is due to the gas flow through the non-combustible zone. To clarify the effect of gas flow through the non-combustible zone, varying the angle from horizontal to vertical downward fire spread, fire spread can be prevented in the narrow width of non-combustible zone.

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Flame spread along a sheet of filter paper under a centrifugal force field was investigated. Experiments were performed in a opposed gas flow of 0.5m/s, with a range of rotation from 0 to 3.5 rps. The flame spread rate increases with increase of rotational speed and has a maximum value around 1rps. The flame becomes to be round shape under low rotational speed, while in high rotational speed it is stretched in the direction of down-stream. It is possibility to simulate the flame spread in different gravity level with normal gravity using a centrifugal force field.

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The effect of sample width on limitation of flame spread along a sheet of filter paper was investigated under microgravity environment. The test sample having three different kinds of width, 50, 60 and 80mm were employed. The opposed gas flow rate was 3cm/s, with oxygen concentration from 17 to 25 vol%. As sample width increases, the spreading flame separates to be cell flame in the direction of width. The amount of oxygen supply diffusion increases due to becoming cell flame. Therefore, the minimum oxygen concentration for flame spread decreases with increasing sample width.

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In this study, the blast wave and flame propagation behavior during a gas explosion of homogeneous premixed combustible gas confined in a spherical soap bubble have been measured simultaneously. The results show that the measured values of the over pressure at various equivalence ratios were larger than those calculated by the acoustical theory. These discrepancies were found to be arisen by the change of the flame propagation velocity in the experiment. The increase of the over pressure in lean mixtures of combustible gas might be induced by diffusive-thermal instability in the flame front. On the other hand, the increase of the over pressure in rich mixtures of combustible gas might be induced by the acceleration of the flame propagation, which is considered to be generated by the sudden rupture of the soap bubble and mixing with the surrounding air.

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The fluid dynamics simulations were carried out to clarify the blast pressure mitigating effects of dike's configuration in hemispherical explosion. For the simplification the back step model could be applied under the small condition for 9, the angle formed by the ground and the line between the explosion core and the dike front corner. From the simulated results, it is clarified that the large 9 provided the great reduction of the blast wave pressure at faraway position. On the other hand, in the small 6 condition, although the peak overpressure recover to the no dike pressure at far place, the mitigated area was formed behind the dike end depending on the dike end position and the height.

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A soap bubble can be used as a capsule, which keeps concentration of the filling gas constant. When nitrogen gas fills in a soap bubble, it is useful for fire fighting like the fire-extinguishing ball. In the present study, the gas motions generated by the collapsed soap bubble have been visualized by using laser tomography method. From the observation, generation of two different kinds of flow from the soap bubble bursting is verified. One is the flow induced by pressure difference of a soap bubble, and the other is the flow induced by dynamics of the converging soap-liquid film. These flows affect significantly characteristics of the soap bubble extinguishment.

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Inert gas extinguishment of a small pool fire with a rubber balloon has been investigated. Rubber balloon is used as extinguishing capsule, which is filled with extinguishing gas and bursts spontaneously at near flames. The rubber film prevents gases in the balloon from diffusing into the surrounding air. In the present study, effects of the membrane thickness on the rubber balloon extinguishment of n-Heptane pool fire have been clarified by using two different kinds of rubber balloons.

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Tar is one of the main problems in biomass gasification because tar condenses at low temperature and it plugs pipeline in gasification process. Therefore, it is important to understand the mechanism of tar generation and decomposition. We propose a method to separate tar to light, medium, and heavy tar by changing of condensation temperatures. In this research, the effect of velocity through the traps on tar yield was investigated. It was found that the flow rates in the range of 0.2-0.6 l/min do not affect the tar yield for each trap, the mechanism of tar generation and decomposition of each tar is different, and over 50 percent of cellulose converts carbon monoxide by providing long residence time.

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For the electric power generation by the woody biomass gasification, tar is incidentally formed at the same time. Partial combustion process is applicable to a reduction technique of the tar in the producer gas. During the partial combustion process, cracking and polymerization of tar occur simultaneously at the proximity of the inverse diffusion flame. This polymerization of tar into soot is a significant problem in the gas reformer with the partial combustion method. We focus attention on hydrogen abstraction reaction in growth mechanism of poly cyclic aromatic hydrocarbon (PAH) that is precursor of soot. The Opposed-flow Diffusion Flame model (OPPDIF) is introduced to investigate the effects of hydrogen and steam addition to the oxidizer on PAH growth. The calculation results show that forward reaction of H abstraction reaction is inhibited by the hydrogen addition.

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Ignition and combustion characteristics of Bio-coke (BIC, highly densified biomass briquette) in high temperature air flow have been investigated. In the present study, ignition behavior is observed, and the mass loss rates for flaming combustion and surface combustion are measured. The experimental results showed that the surface ignition precedes gas-phase ignition in the case of high temperature air, while surface ignition and gas-phase ignition simultaneously occur in the case of low temperature air. Consequently, it is suggested that the temperature distribution inside BIC, i.e. the preheating condition which is correlated with air temperature and air flow rate, strongly affects on the ignition modes and subsequent combustion rates.

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In order to develop a small-scale gasifier in which biomass can be converted to energy with high efficiency, we planed a gasification process that consists of two parts: pyrolysis part (rotary kiln) and gasification part (downdraft gasifier). We performed fundamental experiments on gasification part and discussed the apropriate conditions such as air supply location, air ratio, air temperature and hearth load. We considered the results by calculating reaction rates of representative reactions on char gasification part and found that water gas reaction is dominant and its behavior gives important imformation to decide the adequate length of the char layer.

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This paper describes that selective liquefaction characteristics of polystyrene in waste plastics and fuel characteristics of biodiesel fuel, BDF, liquefied polystyrene as diesel fuel. In experiment, expanded polystyrene, EPS and polystyrene paper, PSP were liquefied in soybean oil methyl ester. As the result, it was found that the kinematic viscosity of liquid increases with an increase of PS concentration in BDF. It was clarified that the increase of kinematic viscosity of BDF liquefied PS was due to molecular weight of PS. The self-ignition quality is decrease with an increase of PS concentration in BDF. The BDF with EPS concentration of 2 mass % is little change as compared with neat BDF.

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Bio-oil/char slurry from wood biomass is an attractive and novel fuel with advantages in energy density, storage and transportation. In this paper, limitations in the performance of free-fall (drop test) reactors are discussed first. Then the characteristics of the yields of quasi-bio-oil and its slurry produced by "intermediate speed (10-60 s residence time)" pyrolysis of Sugi-material, are discussed as the first stage in the development of an effective process. Intermediate-rate pyrolysis has important engineering advantages relative to conventional fast (0.5-2 s residence time) pyrolysis. It is shown that quasi-bio-oil/char slurry has the potential to provide a good source of low-quality industrial fuel.

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The volume reduction process was closely connected with the pyrolysis and divided three regions; i) region of dehydration from biomass, ii) region of pyrolysis of cellulose and iii) region of pyrolysis of lignin. The process could be expressed by the reversible first-order chemical reaction model. Apparent density of the packed bed of biomass particles depended on the temperature. Especially, the density at T > 623 K became about 60% of that at room temperature. Furthermore, time course of average temperature in the biomass layer can be reproduced by the numerical simulation of the thermal conduction through the pyrolysis, which is included in the change of the apparent density and the change of the biomass surface by the volume reduction.

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This study focused on the pre-process of extracting sugar that is very essential in bioethanol production system to promote its efficiency. To do it, the freezing step was introduced into the first process. Furthermore, the effect of the kind of wood, the size of wood chips on the extracting efficiency of sugar was also investigated. As a result, there is a little difference in sugar concentration sue to the kind of wood. The bigger is the size of wood chips, the higher is sugar concentration with the short time. The effect of freezing step introduced was not seen.

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Ethanol oxidation in subcritical water was examined at 25 MPa in the temperature range of 260-350 ℃ with equivalence ratio of 0.6. With oxygen as the oxidiser, the overall first-order decomposition reaction parameters were determined to be 10^<2.9±0.4> s^<-1> for the pre-exponential factor and 53.8±4.6 kJ-mol^<-1> for the activation energy. The products obtained by the hydrothermal oxidation of ethanol were acetaldehyde, acetic acid, carbon monoxide and carbon dioxide. First-order kinetics was enough to capture the main characteristics of species concentration profiles. Consecutive reaction network: C_2H_5OH→CH_3CHO→CH_3COOH→CO→CO_2 well described the behaviour of components obtained from wet oxidation of ethanol.

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The authors try to reveal the dominant chemical reactions and the optimum conditions, supposing the design of ethanol steam-reforming reactors for hydrogen production. Experiments are conducted for Cu/ZnO/Al_2O_3 catalyst. Using a household-use-scale reactor with well-controlled temperature distributions, we specify the effect of liquid-hourly space velocity LHSV upon the ethanol conversion X_<C2H5OH> and upon various concentrations. Furthermore, we compare experimental results with chemical-equilibrium theories. As a result, the obtained concentrations suggest that the dominant chemical reactions at LHSV < 0.2h^<-1> are different from those at LHSV > 0.2h^<-1>.

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In this research, we used the sawdust and water-vapor which are raw materials, and produced the bio-fuel, hydrogen. As the method, we used the shock heating by the shock wave driven from high pressure gas. The experimental apparatus is the standard shock tube. As a result, the temperature which is the most efficient in the hydrogen concentration measurement is about 1000〜1100K. In these temperatures, the hydrogen concentration is about 40% at the maximum. To get high hydrogen concentration, it is necessary to increase the sawdust volume and water-vapor pressure, molar quantity, in the same ratio.

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We proposed a non-invasive heating method using the re-entrant resonant cavity applicator system for deep-seated brain tumors. We have already confirmed the effectiveness of this heating system by experimental results and computer simulations with an agar phantom. This paper describes the specific absorption rate (SAR) analysis of this heating system with 3-D human head model for non-invasive brain tumor hyperthermia treatments. First, we described a method of reconstructing a 3-D anatomical human head model from 2-D MRI and X-ray CT images using 3D-CAD software. Second, we presented the results of the SAR distributions of this heating system with developed 3-D anatomical human head model. From these results, we found that the possibility of clinical heating using this system was confirmed by estimating SAR distributions with developed model.

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This paper describes heating properties of the developed coaxial needle applicator made of a shape memory alloy (SMA) for brain tumor hyperthermia treatments to avoid undesirable hotspots. We estimated the temperature distribution inside an agar phantom by the finite element method (FEM) and heated the agar phantom with the developed needle applicator. Here, first, the structure of the developed coaxial needle applicator made of the SMA was presented. Second, the results obtained by computer simulations and the experimental heating results of the agar phantom with the developed SMA needle applicator were presented. After comparing computer simulation results and experimental results, we discussed the heating properties of the developed applicator. Finally, from these results, it was concluded that the developed coaxial needle applicator made of the SMA is useful for invasive hyperthermia treatments.

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Controlling postoperative course is serious problem in liver transplantation. The transplantation changes blood flow balance in the liver consequently causes on local and overall swellings (deformation) of the transplanted liver. In order to prevent such the diseases prediction method is required before the transplantation surgery. This study build analytical method for blood flow in portal vein; geometric model was made from patient's CT image data and performed Computational Fluid Dynamics (CFD) analysis of blood flow in the portal vein. As a result of analysis, it was confirmed that this method was able to predict actual blood flow balance in the portal vein because the tendencies of calculation and measurement results conformed each other. In addition, blood flow in the left lobe of the portal vein showed different flow characteristics compared with right lobe; eddies were proceeded in the left lobe. These results mentioned here lead us detail blood flow characteristics in the portal vein and contribute to elucidation of the vascular disease.

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Obstructive Sleep Apnea Syndrome (OSAS) is one of nasal disorders. In order to develop effective treatment for OSAS it is needed to discuss and survey not only from medical but also engineering points of views. The purpose of this study is to get the knowledge about the OSAS from engineering standpoint. This study made a three-dimensional geometry model of the respiratory organ which includes nasal, pharynx and larynx by means of OSAS patient's CT data, and performed Computational Fluid Dynamics (CFD) analysis for breathing air flow characteristics in respiration process. As the results of the analysis, this study confirmed eddies were generated and transported in all over the respiratory organs. In addition this study made clear that inhalation and exhalation wall share stresses. There were high wall share stress areas on anterior wall in the inhalation process, on the contrary posterior wall in the exhalation process. These characteristics affect on the development mechanism of OSAS.

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We have carried out an experiment on the gradual, one-directional freezing procedure for the aqueous solution of antifreeze protein type I (HPLC6). We have measured temperature profiles by using a near-infrared camera. We have estimated heat flux from the measured temperature. In the case of pure water, the sum of the conduction heat flux in the water and the heat flux for the solidification is found to be in agreement with the conduction heat flux in the ice. On the other hand, the conduction heat fluxes of HPLC6's solution and ice are found to be lower than the heat flux for solidification.

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An optical densitometer was developed to monitor the change of solute concentration of the solution supplied to a perfusion microscope, which has been developed to observe osmotic response of cells. The concentration of a solution that was supplied to a channel with a 0.5 × 0.5 mm^2 square cross section was determined from the position of a laser beam that passed through the channel, utilizing the change in the refractive index with the concentration of the solution. Real-time measurement of the concentration change was demonstrated with the device installed in the perfusion microscope for several patterns of concentration change.

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Although purpose of food freezing is to suppress the deterioration of food, freezing breaks food tissue down, and some nutrient and delicious element flow out after thawing. Recently, food freezing process with electric and magnetic fields has attracted much attention from food production companies and mass media. This paper presents an experimental investigation on effects of magnetic field on food freezing process. Water, saline water and iron sulfate solution were frozen in magnetic field (200kH, 1.3mT), and their freezing curves were examined. A little effect of the magnetic field was found for saline water, and subcooling of about 12℃ was obtained. However, iron ion in solution did not seem to influence freezing in magnetic field.

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To understand the heat transfer characteristics in fluidized bed, the particle convection becomes the important factor. And its characteristic depends on the particle size. In this investigation, heat transfer experiment under a forced particle convection was conducted by using the cylinder-shaped fluidized bed with stirrer. In the experiment, several sizes of particles (d_p = 0.2mm, 0.4mm, 1.0mm) were used. As result, time-averaged heat transfer coefficient was a function of the residence time. And experimental result has been estimated by using a simple heat transfer model with effective thermal conductivity.

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Characteristics of the thermo-sensitive hydrogel have been studied to be used in negative thermal expansion particles composed of compressible gas and positive thermal expansion material. Interpenetrating polymer network gel of polyacrylamide and polyacrylic acid was synthesized and examined its swelling ratio or swelling pressure at various temperature conditions. Without volumetric constraint, The gel absorbed water and increased its weight 2.8 times at 10 ℃ and 11 times at 50 ℃ as much as that at dried state. At a given isometric condition, the same gel showed the increase of swelling pressure up to 30 kPa.

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The swelling is an increase of volume of material due to absorption of a solvent and is an important phenomenon in soil and gel sciences. We have investigated the frost heaving experimentally, using bentonite particle which is a type of swelling clay. When moisture-contain soils freeze, soil particles are often swept from frozen layer. In case that soil particles are perfectly swept out from frozen layer, pure ice layer which is called ice lens is formed. The freezing distribution coefficient is an important factor to form ice lens in the soil. It strongly depends on the freezing rate and interfacial solid ratio. It was found that the present swelling model for frost heaving corresponds to the experimental results for the increase in pressure due to frost heaving.

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We investigated on direct decomposition of a gas containing N_2O by shock tube and ignition device of imploding detonation type in the present study. Our purpose is to show the treatment temperature as nitrous oxide was decomposed and the effect of H20 as additive. In the single shock wave experiment, one is experiment of using differential pressure by driving gas He, the other is experiment of ignition by fuel CsHs. As a result, the highest decomposition 99 % was obtained in the single shock wave experiment and 54 % was obtained in continuous experiment. We found that treatment temperature and duration of shock wave are important parameters in N_2O decomposition.

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An experimental study has been carried out on the synthesis of carbon nanomaterials using Ni wire in methane / air laminar, fuel-rich premixed flames under atmospheric pressure. By placing a pair of porous media in the upstream and downstream sides of the combustion space, excess enthalpy burning was applied to the methane / air mixture. We have investigated effects of reaction time and height of Ni wire on nanomaterials growth. As a result, it has been clarified that carbon nanomaterials with a diameter of from 20 to 50 nm are synthesized in the downstream side of the exothermic reaction zone.

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