The double diffusive natural convection during the freezing from the top surface of an aqueous solution was numerically studied at the Prandtl number Pr=13,the Lewis number Le=100,the Rayleigh number Ra_0=10^6 and the buoyancy ration N_0=0.5,1 or 5. At first, a boundary layer of concentration was formed near the top of solution with time. Then salt-finger phenomena occurred and the solute accumulated near the bottom of the vessel. The finger pattern depended on the ratio of cooling square area to entire surface area, the buoyancy ratio and the freezing velocity.

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This paper presents a method to optimize thermal and flow boundary conditions using an adjoint numerical analysis in mixed convection heat transfer problem. The numerical solutions for the adjoint problem indicate sensitivities of heat transfer characteristics such as temperature distribution or total heat transfer. It is shown that applying the sensitivities to the gradient-based method enables us to optimize heat transfer characteristics efficiently for thermal and flow boundary conditions. Illustrative example is presented to demonstrate the proposed method.

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This paper deals with improvement of heat transportation by pulsatory flow that is an oscillatory flow imposed with a steady flow. Velocity profile and temperature profile were numerically analized. It was found that heat transportation was increased about 10 times as much as the oscillatory flow when w_<st>=0.01w_<osmax>.

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An active heat spreader is an oscillation-type heat pipe that is a closed meandering pipe with two bubble pumps at the both ends and with several heating and cooling sections on the way of one, in which a working fluid is charged adequately. In the present paper, the prototype device was built and tested for checking the operation. As a result, in he case of AHS with single-tube-type bubble pumps, the fluid is awkward in it's movement and it can not transport heat from the heating section to the cooling sections, but AHS with double-tube-type bubble pumps can transport heat well, although the periodical fluctuation of the temperature on the heating wall is appeared.

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This paper describes a new passive thermal control device - a Reversible Thermal Panel (RTP), which changes its function reversibly from radiator to solar absorber by deploying/stowing the radiator/absorber reversible fin. The RTP experimental model was designed and fabricated using highly oriented graphite sheets (HOGS_S), honeycomb base palate and shape memory alloy (SMA). The heat rejection performances and autonomous thermal controllability were evaluated by the thermal vacuum tests. The test results show the excellent performances of the RTP as a passive radiator in the point of specific heat rejection. The necessity of designing the reversible rotary actuator with SMA, which has higher deployment torque, was revealed.

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This review article has mentioned the present research and development on flow drag and heat transfer characteristics of flow drag reducing flow by adding a small amount of surfactant to the hot and cold water. Especially this article has focused our attentions on heat transfer recovering methods of flow drag reduction water solution flow in a heat exchanger from previous reports.

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The flow drag and heat transfer reduction effects of brine flow with drag reduction surfactants have been investigated from the effective energy consumption in a pipeline system. In this study, Oleyldihydroxyetyl Amine Oxide (ODEAO) was used as a drag reduction surfactant additive, and Ethylene Glycol (EG) solution was selected as the brine. The pipe friction coefficient and mean heat transfer coefficient of the EG solution flow with ODEAO were measured as parameters of EG concentration, solution temperature and ODEAO concentration. The obtained experimental results indicated that the EG concentration exerted an influence on the flow drag and heat transfer reduction characteristics of the EG solution flow with ODEAO.

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The drag reduction of a water flow with new drag reducing surfactants (amine oxide type nonionic surfactants, mixtures of amine oxide type nonionic surfactants and betaine type amphoteric surfactants) which were selected as environmentally acceptable drag reducing additives was investigated experimentally. Addition of amine oxide type nonionic surfactants to hot or cold water can reduce flow drag in a turbulent pipe flow. The present research investigated how various ionic components dissolved in water affected this drag reducing effect. It was found that ionic impurities contained in the water affected the pipe flow drag reducing effect by amine oxide type nonionic surfactants. Moreover, it was clarified that the decrease in the pipe flow drag reducing effect was recovered by adding a mixture of amine oxide type nonionic surfactants and betaine type amphoteric surfactant to the water with ionic impurities.

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The present experiment is conducted to examine the shear-induced structure of surfactant solutions in the flow around a single cylinder in the Reynolds number range from 100 to 2000. We perform flow visualizations and velocity measurement. It is found that the wake region behind a cylinder becomes small as the Reynolds number is beyond a certain value, which depends on the cylinder diameter. The build-up of the shear-induced structure is suggested to take place a critical shear rate from 10 to 18 s^<-1> in spite of the cylinder diameter.

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The addition of a small amount of surfactant to water shows the unique characteristics to reduce the skin friction of the flow tremendously. The heat transfer performance of the surfactant flow correspondingly becomes deteriorate in the drag-reducing flow. In the present study, the reduction of both friction coefficient and heat transfer rate was confirmed experimentally, and the local recovery of heat transfer rate was examined when an obliquely discharged jet was introduced in a confined flow field. The near-wall velocity profiles measured with PIV system were also discussed in comparison between the flow conditions of surfactant solution and pure water.

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This study investigates the influence of temperature-dependent physical properties in drag-reduced flow to clarify at which location temperature should be changed in order to contribute to drag reduction, by effecting wall heating so as to arrange a vertically and longitudinally "non-isothermal field" in channel flow. Flow characteristics and temperature profiles have been measured by an LDV system and a fine thermocouple probe. A difference in velocity profiles between the cases of T_w=44℃ and 48℃ has been observed : the former is distributed along the profile for drag-reducing flow, and the latter is similar to that for water as turbulent flow. Investigation of the effect of non-isothermal heating on drag-reducing flow revealed that the temperature dependent condition of flow and temperature field in the buffer layer (50<y^+<100) is an important factor for controlling heat transfer in the drag-reducing flow.

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In surfactant solution (TTAB+NaSal), the pipe friction factor and heat transfer coefficients were investigated. The straight circular tube of D=5.0mm in diameter and L=2800mm in total length was used. In the drag reduction flow, in order to break micelle structures and to promote heat transfer, the "micelle breaker" was installed in the upper stream of the testsection. As a result of the experiments, in surfactant solution (1000ppm), compared with the case of water, the friction factor decreased 75% in Re=11000,and NuPr^<-1/3> decreased 75%. However, installation of the micelle breaker increased NuPr^<-1/3> by 1.8 times compared with the case where it does not install.

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Statistical characteristics of turbulent heat transport in the thermal boundary layer of a drag-reducing surfactant solution flow in a two-dimensional channel have been experimentally studied, by simultaneously measuring the velocity and temperature fluctuations. Statistical analysis was carried out for the following terms : temperature fluctuations, turbulent heat fluxes in the streamwise and wall-normal directions, turbulence production of temperature variance, eddy diffusivities and turbulent Prandtl number. Influenced by the drag-reducing additives, the wall-normal turbulent heat flux was significantly depressed, causing depression of turbulent production of temperature variance and thermal eddy diffusivity.

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A direct numerical simulation (DNS) of turbulent heat transfer in a channel flow was carried out to investigate turbulent heat transfer mechanism of drag-reducing surfactant solution. The configuration was a fully-developed turbulent channel flow with uniform heat flux imposed on both the walls. The temperature was considered as a passive scalar with the effect of buoyancy force neglected. A Giesekus model was used to model the extra stress associated with the deformation of the network microstructure formed by rod-like micellar structures. The Reynolds number based on the friction velocity and half the channel height was 150. Statistical quantities such as root-mean-square temperature fluctuations, turbulent heat fluxes and turbulent Prandtl number were obtained and compared with those of a Newtonian fluid flow. Budget terms of the turbulent heat fluxes were also presented.

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A model to simulate the drag reductoin by dilute addition of polymer or surfactant (Toms effect) is proposed based on the discrete element model. The dimension of the discrete element, which represents the polymer or the rod-like micelle, is very small compared to that of the velocity fluctuation of the fluid. So it is assumed that the element is in equilibrium state in the fluid and turns to the direction of an eigenvector of the velocity gradient tensor. And the macroscopic effect of the discrete elements is modeled as the stress assuming the elements are independent each other. Direct numerical simulations are carried out with this new model using the rigid dumbbell element as a discrete element model and it is shown that the drag reduction up to 37% drag reduction rate is reproduced. In addition the temperature field in the drag reducing flow is simulated.

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An electrokinetic process for the separation and/or filtering of charged order one-micron diameter particles in solution is demonstrated. Two buffered particle-laden streams of different ionic conductivities are introduced through a T-shaped microchannel. The fluid is driven by both pressure and a DC electric field. Upon application of an electric field, the particles are extracted from the lower conductivity stream and stacked into the higher conductivity stream. Both particle density imaging and quantitative velocity fields using micron-resolution particle image velocimetry are presented. Numerical simulations of the process in the conductivity gradient show the generation of a transverse electric field, therefore force acting on particles is selectively controlled in a simple microchannel.

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Transient characteristic of electric double layer which will be a key issue for a microscale multiphase flow system in future was investigated by using micron-resolution particle image velocimetry. The present study focused on deprotonation at glass surface by varying pH of buffer solutions, inducing a change in ξ-potential of glass surface. Time-series measurements of ξ-potential were first achieved by using experimental data of electroosmotic mobility that was calculated by subtracting electrophoretic velocities of sub-micron particles from observed velocities. The ξ-potential at a steady state showed a good agreement with the theoretical one.

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Brownian motion and cluster formation of non-magnetic particles in a magnetic fluid were investigated using an optical micro-scope system. Real-time visualization of cluster formation of non-magnetic particles were carried out by using micro-scope and high speed camera. The analysis of digital images with Particle Tracking Velocimetry (PTV) was applied to investigate the motion of non-magnetic particles. The mean velocity and mean cluster length of non-magnetic particles in cluster formation were analyzed.

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In this paper, a forced motion of fine solid particles in liquid, induced by a laser beam is discussed. The irradiation of focused laser beam generates the gradient force, which enables to trap fine particles in three dimensions. New phenomena have been observed. One of the phenomena is that the particles around the focus point of the laser beam gathered and then left from the point. Our experimental system contains CW Nd^<+3> : YAG laser, which has 1.064micron in wavelength, and optical microscope. The motion of particles was monitored by a CCD camera on top of the microscope and recorded in VHS.

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Recently, the demand for fabricating the simple microstructure of silicone, such as groove of MEMS device, by simple method is increasing. We investigate the laser-assisted wet etching technique to meet this demand. This method has the possibility of maskless processing and is good for various small-lot production. Also the laser-assisted wet etching is superior to laser ablation or micro lathe in fine dust free. In the experiment, silicon etching was performed by using short pulse laser and the feasibility of the laser-assisted wet etching of silicon is exhibited. We are going to perform a numerical calculation to understand the physical aspects of the etching technique.

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A flow channel with the cross-section of a half circle was grooved on the Plexiglas plate. The length and the diameter of the flow channel were 26mm and 0.5mm, respectively. A patch electrically-heated was located at the off-set location from the center between both ends of the flow channel; at 8.5mm from the one end and at 17mm from the other end. The heating length was 0.5mm. The flow channel was filled with distilled water and the heating patch was heated periodically. One coalescent bubble was formed and condensed to disappear synchronizing with the pulse-wise heating. While this bubble formation and condensation continued periodically, flow from the short side to the long side in the flow channel was maintained. The flow rate increased as the heating rate was increased. The flow velocity and the flow rate obtained in the present experiments were 0.2&acd;6.5mm/s and 0.03&acd;1.35(mm)^3/s, respectively. The velocity of the interface between the bubble and liquid during the condensation period was much faster than that during the evaporation period. During the condensation period, the velocity of the interface at the short side was faster than that at the long side. The equation of motion of liquid in the flow channel was solved to calculate the traveling of liquid in the flow channel. Predicted velocities qualitatively agreed well with the experimental results. By applying the duration times of evaporation and condensation obtained in the present experiments to the predicted velocities during the respective evaporation and condensation period, an average flow velocity during one cycle of heating was derived. The flow velocity so obtained qualitatively agreed well with the experimental results.

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Fundamental characteristics of a micropump system driven by surface tension are studied on the basis of two-dimensional numerical analysis. Since the surface tension is controlled by the temperature difference between the hot and cold junctions of the thermoelectric elements, the equations for liquid and gas phases are formulated by coupling them with the energy equation for the thermoelectric elements. In particular, using boundary-conforming grids, the effect of the interface deformation was taken unto account. By systematically varying the contact angle as well as the interface height, the variations of the flow rate are discussed.

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A micro flow regulating element for integrated chemical devices was developed and its thermal behavior was evaluated. The temperature dependence of liquid viscosity was utilized to perform a continuous volume flow control in nano-liter/minute region, without mechanically actuated parts. A parylene-based suspended micro channel with a heater and a temperature sensor was realized for thermal insulation. The amounts of thermal energy losses to the substrate and the ambient air were estimated through a model calculation. The experiment using a prototype device demonstrated a reasonable flow regulation performance. The results of energy loss estimation were compared with the experiment, and the causes of discrepancies were discussed.

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Direct numerical simulations of flow induced by a zero-net-mass-flux jet (ZNMFJ) actuator are performed in order to investigate the effects of the Reynolds number and Strouhal number on the formation of jet flow above the orifice. It is found that the ZNMF jets are realized when a vortex pair formed during the blowing period at the orifice advects away from the orifice, in such a way that the pair will not be sucked into the cavity during the suction period. This condition can be described with U_j (U_j/f)/v>1000,where U_j is the mean velocity at the orifice, f the frequency of the membrane, and v the kinematic viscosity.

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Direct numerical simulation of laminar flow in model heat exchangers with oblique wavy walls is made in order to assess the heat transfer and pressure loss characteristics for the optimal shape design of recuperators. The effect of oblique angles of the wavy walls is systematically evaluated. It is revealed that the flow structures are drastically modified due to the strong secondary flow induced by the wavy walls, and that the heat transfer enhancement could be greater than the pressure loss penalty with optimal surface geometries and flow configuration. It is also found that the averaged Nu number is increased when thermal coupling of hot and cold fluid passages is considered.

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In the present study, a micro bare-tube heat exchanger without conventional fins is propsed and evaluated for electronic equipment cooling application. A micro bare-tube heat exchanger composed of 0.5mm outer diameter copper tubes is manufactured and tested experimentally. The optimal dimensionless transverse and longitudinal tube pitches were around P_T=2.3 and P_L=1.3,respectively. It is shown that the resultant micro bare-tube heat exchanger can drastically reduce the core volume compared to that of the conventional plate fin and tube heat exchanger.

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Experiments were conducted to study the effect of the location of LSI chip on the heat transfer performance of a natural circulation, evaporative cooling system for LSI chip. A test silicon chip with dimensions of 10×10×0.5(mm)^3 was mounted on the bottom surface of a horizontal rectangular duct located at the bottom of the natural circulation loop in which FC-72 was filled. The space height of the duct s was set at 1,10 and 25mm. A smooth chip and a chip with square micro-pin-fins were tested. Experiments were conducted at the liquid subcooling ΔT_<sub> of 10,25 and 35K. Comparison of the results revealed that the highest performance was obtained by the micro-pin-finned chip with s=10mm.

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Fundamental study has been performed to develop on Joule-Thomson microcooler which was fabricated on Si wafer by photo fabrication. The microcooler in the present study uses ethylene as a refrigerant. Inlet and outlet gas pressure are set at 2.3MPa and 0.1MPa, respectively. Peltier device was used to condense ethylene. Liquefied ethylene was observed when condenser temperature reached saturation temperature. Evaporator temperature reached 235K with mass flow of 8.9mg/s.

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The components of a novel miniature fuel cell/fuel reformer system fueled by liquid gases such as butane and propane were prototyped using MEMS technology and tested. In this system, fuel, air and water are supplied to the fuel reformer by utilizing the vapor pressure of the liquid gas for the reduction of power consumption by peripherals and the simplification of the system. The system is composed of a reforming reactor, a catalytic combustor, a polymer electrolyte fuel cell (PEFC), an ejector to supply air to the combustor and other peripherals. The reforming reactor demonstrated the steam reforming of methanol at an equivalent power of 200mW and a total efficiency of 6%. The combustor had a stable combustion area above 5W, and the complete combustion of butane was confirmed by gas chromatography. The ejector showed a potential to supply air required for the complete combustion of butane (31 times larger volume than butane).

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A direct methanol fuel cell (DMFC) is considered as prospective power sources for portable devices and is studied intensively. Although a fuel-strage-type one seems to be much practical, in many cases, experiments using a fuel-supply pomp are conducted. In this study, effects of fuel feed method on DMFC performance are investigated. It is shown that the output power of fuel-storage-type DMFCs decreases gradually because of development of a concentration boundary layer and so on. Next, a simple method for estimation of fuel concentration at the anode catalysis layer is proposed and its effectiveness is shown. Finally it is shown that by supplying fuel as a vapor, DMFC keeps higher performance than that of a liquid-feed type, but because of dry up of membranes, its performance goes down significantly after a long operation.

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Chemical propulsion for micro-spacecraft is preferable to electric propulsion when it is difficult to supply large power and high voltage. One of the key technologies of chemical MEMS propulsion is the catalytic reaction and so far several attempts were carried out in order to improve the micro reactor or combustor. However, they either show poor activity due to film deposition method or need embarrassing procedure for fabrication. This paper treats porous silicon as the catalyst bed of platinum particle and discusses its performance for micro propulsion reactor. LPCVD silicon nitride film on N-type silicon wafer is used as both masks for bulk-etching of microchannels and anodization for porous silicon. By using H_2PtCl_6 solution, platinum particle is successfully deposited on the macroporous silicon surface and active propellant reaction is accomplished.

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Most heat generated in thin film resistor of Power MEMS dissipates into substrate even though it is used to warm the working gas or propellant. In order to reduce such waste of power, high-performance thermal insulator is required to develop between thin film heater and substrate. Silicon dioxide film is treated because of its popularity for MEMS technology and variety of thermal property. In order to inquire the more effective thermal isolation structures suited for Power MEMS, double SiO_2 layers are made up of different process on silicon wafer. Such double layer has two thermal interfaces, which disturb heat transfer. By using the 3 omega method, the thermal conductivity of SiO_2 thin film layers and interfacial resistance are measured. Optimum SiO_2 structure using multiple films suited for Power MEMS especially for micro thruster is proposed and discussed.

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Ultra micro turbine concept based upon MEMS technology was proposed by MIT, since then several projects have been initiated and sponsored by DARPA for its development throughout the universities and research institutions in the US. The present authors regard such ultra micro gas turbine engine systems to be crucial for the future mobile and friendly energy utilization system that anyone can enjoy at any place on the globe. In this paper, out palm top gas turbine (2-3kW, dry weight 14.3kg included generator, rotational speed 235000rpm, outer diameter 180mm, length 335mm) and finger top gas turbine test model (tens of W, rotational speed 1170000rpm, outer diameter 23mm, length 32mm) are described.

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Cogeneration systems in business and commercial sector and residential sector compete with other dispersed energy systems such as solar energy utilization systems and heat pump systems in terms of the effectiveness of reducing CO2 emission, primary energy and cost. The author tries to evaluate the competitiveness of CGS by utilizing a multi-objective energy system planning model for urban area. CGS is found to be effective within a certain range of CO2-cost and primary energy-cost tradeoffs.

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Reduction of environmental impact and an achievement of highly efficient utilization of energy resources are important issues for developing a sustainable energy society. In this study, we basically study on the system-design and operation of cogeneration system (CGS). Several facilities should be linked with an energy network and share the thermal energy and the electric power produced from CGS. There is a necessity to predict and control demand of balance on thermal and electric power energy and to operate CGS and other facilities at effective condition through a year. To compute such a complex system, we propose to apply Unified Modeling Language (UML), which is a language for programing object-oriented modeling, to express energy utilization system. As an example of calculation results, we calculated the fundamental simulation for a community including a hotel, hospital, office, shopping, and residential buildings at a climatic condition of Tokyo. This result shows that the present model makes it possible to design appropriate system and to operate of CGS at any load condition, which results to be able to reduce environmental impact.

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We proposed "Energy chain" methodology as an effective evaluation tool for total energy system using electricity form grid and Co-generations. The energy chain concept is defined as energy flow from source to energy consumption to final end use energy benefit in terms of heating, cooling, lighting and other benefits of energy. Two indices are proposed to measure the effectiveness of this process. The first of these is the Energy chain joule index (ECJI) which expresses the extent of energy conservation. The second is the Energy chain carbon index (ECCI) which expresses the extent of greenhouse abatement. In future, this concept and evaluation methodology is made public both internationally and domestically. And, an analysis tool using this methodology will be developed and a lot of evaluations examples will be accumulate by using the tool.

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The cost down of the electric power and city gas has been realized because of the active promotion of the deregulation in the energy business. From the viewpoint of global environment problem and economic slump, the technical innovation is desired to enable to abate emission of CO2 and to create the new jobs. The high efficient distributed generation system such as a SOFC or a MCFC hybrid is created to present the comfortable and high quality living environment, using combined heat information and power (CHIP) technologies. The key technology of this proposed system is to connect the home and home for one loop of heat transfer line and level the demand of heat consumption using the heat storage systems in the neighboring communities with high efficiency that the stand alone home-use cogeneration system. And the inner diameter of this heat transfer line is only one inch. Using this key technology, this constant heat output can supply about twenty houses in case of Hokkaido area or over sixty houses in case of Kansai area even in winter season because of the sharing of the instantaneous hot water supply demand by the cooperation of the neighboring communities. Sodium acetate with three hydrate or paraffin is used as the phase change material (PCM) for the heat storage systems. At present, to produce on the commercial basis of this system, the academic, companies, and governmental circles composed mainly of the Kansai area have been developed to verify the control logic for leveling the heat duty of mainly heating feed water. This paper presents the concept of this neighboring communities generation (NCG) system compared with the ordinary heat and power supply system and the test result of New Heat Supply Unit (NHSU).

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Because of their potentials for cost and energy savings by efficient utilization of exhaust heat, cogeneration systems have been installed into industrial and commercial sectors. The overall performance of cogeneration systems is evaluated from economic, energy saving, and environmental viewpoints, and is affected by many factors. In this paper, an optimization approach to design and operation of cogeneration systems in consideration of the factors is presented. As an example, the trade-off relationship between economic and energy saving characteristics is analyzed on a phosphoric acid fuel cell cogeneration system.

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The paper analyzes the optimum cogeneration system (CGS) for the reduction of greenhouse gases. The paper compares the CGS characteristics for building types, system structure, power grid connection and operation patterns. The result shows that houses have the greatest potential to reduce greenhouse gases among variety types of buildings and power grid connection of houses is essential for the reduction. To realize the system the authors propose a concept of cooperative cogeneration network system, which equips heat storage and operates flexibly to flatten energy demand in the grid.

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To keep high performance in Polymer Electrolyte Fuel Cell (PEFC). it is important to realize uniform current density and temperature distribution over the reaction area. Tow types of fuel cells were made to measure temperatures in the cell : a cell containing 12 thermocouples in a thin carbon plate between the two cells, and one allowing visual observation of temperature distribution in the cell. The experimental results showed that hot spots appeared in the flooding condition and the temperature tended to be uniform when the flooding was removed. The optical observation show3ed the increasing temperature from the inlet side of cathord gas, but the same temperature change was observed even when the flow direction was reversed. The reason is not clear at this moment.

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This paper discusses mass transport characteristic of sodium vapor in a miniature alkali metal thermal to electric converter (AMTEC) cell. The miniature AMTEC cell, which has larger packed electrode area in the same volume, is expected to have a feature to increase its volumetric power density. For the design of the cell discussed here, the main consideration is pressure drops due to sodium vapor flow between the cathode side electrode and the condenser surface. Mass transport characteristic in thin molybdenum electrode was measured with the sodium exposure test cell (SETC) in the temperature range of 900K to 1050K. The exchange current density and the electrode dimensionless mass transfer factor calculated from the measured limiting current are discussed. Based on the experimental results, the influence of the sodium vapor flow in the cathode side was evaluated. The preliminary parametric analysis shows that a miniature cell element with a sodium beta"-alumina tube of 1mm in outer diameter has a predicted output power of 8.5kW per unit. container base area.

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High efficiency of gas absorption may be one of the important techniques for protection of global environment. We have proposed the new method for Carbon Dioxide gas absorption, that is the condensate film method by utilizing condensation process and the solution condensate method. In present investigation, a new concept of the enhancement of gas absorption by utilizing zeolite particles with mist formation was proposed, and its proof experiment was conducted with regard to the gas absorption rate in vertical cooling tube. By comparing the present proposed method with falling liquid film method and our past-proposed methods, the effectiveness of the gas absorption through the zeolite particles and mist droplet was clarified. Furthermore, the effect of operating condition such as gas flow rate, gas concentration, temperature, vapor concentration and zeolite particle number density was examined.

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The present experiment is conducted to examine density-driven instabilities between reactive fluid layers in a vertical Hele-Shaw cell. The upper and lower layers contain HCl and NaOH solutions, respectively. The former is heavier than the latter, and the system is gravitationally stable. We observe the dynamical evolution of interface for several concentrations using a flow visualized technic. It is found that small ripples appear on the moving reactive interface. The reason for this is due to density-driven instabilities resulting from the productions by chemical reaction on the interface.

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Freezing phenomenon of water including small particle has two special characteristics : (1) the particles are swept from freezing front; (2) the particles are trapped by the progress of freezing. In this paper, we investigate the difference in behavior of glass particle and bentonite particle due to freezing. Two kinds of experiment had been investigated; there are single particle interactions with solidification surface and bulk particles interaction with solidification surface. From these results, it became clear that the critical freezing velocity of bentonite is larger than glass particle. And it became clear that the critical freezing velocity of bentonite strongly depends on the bulk particle concentration.

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Heating characteristics of materials due to microwave heating strongly depend on standing wave formed by the interference between transmitted wave and reflected wave in materials. The purpose of this study is to clarify the effect of wave control layer installed on the characteristics of heating. The layer has two effects, which are to reduce the reflected wave on the surface of materials and to change the interference between transmitted wave and reflected wave. It was found that the wave control layer led to a higher performance.

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In order to burn plastic-resin powder as an alternative fuel and to realize effective energy-recycling of recycled plastic-resin, it is necessary to elucidate fundamental characteristics of a plastic-resin particle subjected to abrupt heating. The abrupt heating method using a CO_2-gas laser as a heat source is employed in this study. High-speed microscopic observations of physical and chemical processes of a plastic-resin particle after abrupt heating are made by combining a microscope with a high-speed CCD video camera. Heating and burning properties of a micro plastic-resin particle are discussed and compared with those estimated by a simplified spherically one-dimensional analysis.

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