This study focuses on the evaluation of biogas as main source of energy for a direct-biogas SOFC-MGT hydrid CHP system. A sensitivity analysis was conducted under various operating conditions to investigate the influence of the key operating parameters of the hybrid CHP system with a consideration of the operational constraints. The key parameters in this study are SOFC reforming agents and SOFC fuel utilization factor (U_f). The study also presents guidelines to achieve the optimum operating conditions of the hybrid CHP system, e.g. the overall system efficiency, SOFC efficiency, the termal energy to electic power raito (TER) and the electric power of MGT to SOFC (P_MGT/P_SOFC), based on the desired heat and power outcomes.

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This paper refers to the performance prediction of the hybrid power generation system, which is made up of a solid oxide fuel cell (SOFC) and a gas turbine (GT), driven with coal gasification fuels (CGFs). The typical fuel compositions of oxygen-blown type gasification plants were adopted in the present investigation. In the case of CGFs, the power generation effectively, because the methane concentrations are very small in CGFs. Without the heat absorption by steam reforming, a larger air flow rate is required to keep the cell temperature constant. Hence, the GT power output is larger in the case of CGFs.

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A new technique for measuring in-plane thermal conductivity of a thin film using a "micro-beam" MEMS sensor was proposed. The principle of the measurement is primarily based on the fact that the steady-state temperature rise of a heated beam-type sensor in a vacuum depends on the heat conductance of the sensor and to determine the thermal conductivity of the film by comparing the temperature rise of the heated senor before and after the deposition of the sample film on the senor. The feasibility of the method was demonstrated by measuring the thermal conductivity of a platinum film deposited on a prototype platinum sensor.

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Thermal analysis and calorimetry are basic techniques to characterize the thermal properties of materials. By the introduction of MEMS technology, highly sensitive and fast response chip calorimeters have been available. This paper reports the melting behavior of an isothermally crystallized PET investigated by the fast scanning calorimetry. In temperature scan rates of 25-400 K/s, DSC curves of the PET shsowed two separate melting peaks because reorganization of the original crystalline structure occurred during temperature scan. On the other hand, fast temperature scans over 700 K/s kept the PET sample original structure and one melting peak of the original crystal was observed in DSC curve.

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TBAB (Tetrabutylammonium bromide) hydrate has advantages as thermal storage material. For example, the phase change temperature, which is from 0 to 12℃, is suitable for use in air conditioning, and the latent heat is relatively large. Thus, thermophysical properties of TBAB hyadrate such as latent heat is useful. However, it is difficult to measure the latent heat with high accuracy by using DSC, because the accuracy of measurement of mass of sample is limited. In this study, large TBAB hydrate crystal is formed and the latent heat of TBAB hydrate is measured using the crysta.

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We are using a vibrating wire method to measure hydrogen gas viscosity under high pressure. Vibrating wire viscometers are based on the principle that small a wire oscillating in a sample fluid experiences a residence to motion that is related to the viscosity of the fluid. Due to the simple and robust construction, vibrating viscometers well suited to extreme conditions such as high pressures and high temperatures. In this time, we are attempting to measure hydrogen gas viscosity in the range of pressures from 0.1 to 1.0MPa and room temperature. And, we are investigating the possibility of using this method for higher temperature hydrogen gas viscosity measurement.

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To understand thermal properties of clothing materials is useful to understand the human heat balance. The influence of solar radiation is large in human heat balance in outdoor and this has major impact on human thermal sensation. Solar absorptance, transmittance, reflectance, and infrared emissivity for six different colored clothing's were measured. Convective heat transfer coefficient for cotton material was also measured. Therefore, heat transfer among human-clothing-environment system was calculated and effect of clothing on human heat balance was clarified.

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This paper reports a visual crystal growth study concerning the separation of carbon dioxide utilizing formation and dissociation of clathrate hydrate. The high equilibrium pressure of CO_2 hydrate may be moderated with the addition of a second guest substance such as tetra-n-butylammonium bromide (TBAB). Visual observations were carried out on the formation and growth of semiclathrate hydrate crystals in the system of CO_2 + TBAB + water. The hydrate crystals first formed in the bulk of the aqueous liquid as well as at the ga/liquid interface. Both of the hydrate crystals then grew into the aqueous liquid. The morphology of hydrate crystals grown in aqueous liquid varied distinctly depending on the system subcooling ΔT_sub.

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We presents a computational scheme to simulate the process of CO_2 capture from a gas mixture simulated CO_2 containing uncornventional natural gas utilizing hydrate formation. We first show the formulations with which the computations are progressed. Illustrative computations are performed to show the evolution of mole fraction in the gas phase during each long-term hydrate-based gas-separating operation. Quantitative predictions are obtained for the increase in the CH_4 mole fraction in the gas phase through the system-composition evolution. The effects of dilute heavy constituents, such as ethane or propane, and impurities, such as nitrogen or hydrogen sulfide, are also discussed.

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This paper reports the four-phase (ice + hydrate + difluoromethane + 3,3-dimethyl-2 butanone) equilibrium pressure-temperature conditions at temperatures (260.8 to 273.1) K in the system of water, CO_2and 3,3-dimethyl-2-butanone. The pressure range of the present measurements in the system is (0.087 to 0.120) MPa. the measurements were carried out using isochoric methods. Phase equilibrium conditions of the hydrate formed in this study were measured to be at higher temperatures and lower pressures than those of the structure-I difluoromethane simple hydrate. The results indeicate that structure H hydrate formed with difluoromethane and 3,3-dimethyl-2butanone is thermodynamically stable exclusively at the temperatures below freezing point of water.

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Idling stop is important to reduce exhaust gas from vehicles for preventing environmental problems such as global warming. Especially, diesel powered trucks discharge harmful gases such as CO_2, Nox and PM. However, refrigerator vehicles used to transport the frozen food cannot do idling stop. A DME fuel-cell hybrid system is an improvement moving system to reduce emissions. The miniaturization becomes the problem for achieving this system and it is important to realize high efficiency reforming. This of efficiencies of reforming with or without Li_4SiO_4.

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Silicon quantum dots (Si QDs) are expected to be high-value added materials for the next generation of devices due to their size dependent optical and electronic properties. We have developed a new synthesis method of Si QDs by using in-flight plasma CVD operated at relatively high pressure, and succeeded in continuous gas phase synthesis of free-standing Si QDs with mean diameter of less than 10 nm. The yield of Si QDs was evaluated in various synthesis conditions and it depends on the specific energy imput (SEL, J/cm^<-3>). From the results of gas analysis and estimation of yield loss on reactor wall, it was revealed that the yields of Si QDs are decided by the balance between SiCl_4 conversion and loss to the reactor wall.

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Different technologies possibly applicable for the large-scale hydrogen storage in urban or industrial-complex areas have been comparatively evaluated, focusing on the facility-construction cost, the utility expense, and the ground area required for the facility for each technology. The specific technologies examined in this study are the storage in the form of a pressurized of liquefied gas, the storage using a metal hydride, and the storage using a clathrate hydrate. The storage using a clathrate hydrate is found to be superior to the other technologies with respect to every evaluation index employed in this study.

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An understanding of dissolution process and phase behavior in oil/CO_2 binary system under high pressure are of great importance to improve the oil recovery rate in carbon dioxide enhanced oil recovery (CO_2EOR). However, the non-equiliborium systems are less well understood even though the equilibrium phase behaviors in the binary systems have been reported by many researchers. In this study, the non-equilibrium dissolution process in decane/CO_2 binary system was observed. CO_2 concentration disribution in the liquid phase was measured by using laser Raman spectroscopy. Moreover, liquid-liquid-vapor three phase equilibrium in decane/CO_2 binary system was successfully observed when the pressure is being reduced.

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Improvement of the oil recovery rate is of great importance for carbon dioxide enhanced oil recovery (CO_2EOR). However, effective way to improve the efficiency of CO_2EOR is still not completely understood because of complexity of dissolution phenomena; swelling, reduction of viscosity and interface tension. In this study, fundamental dissolution and swelling process of decane/ CO_2 was observed under high pressure. As the result, it was calculated that the rate of swelling in the vicinity of the interface increases rapidly. It was also observed that the partial pressure of CO_2 has a dominant influence on the rate of swelling.

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CCS is considered as an effective technology to reduce CO_2 emissions into the atmosphere. Geological sequestration is an immediately available and technologically feasible method, however, upward migration of CO_2 is caused by buoyance. The evaluation of the storage site and the assessment of CO_2 leakage risks and storage costs are needed. To clarify the behavior of CO_2 migration, we studied fundamental liquid CO_2/water two-phase flow in a porous media. One dimensional distribution of CO_2 saturation and its time evolution were simulated. Necessity of considering the pressure loss in both phases was discussed.

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Improvement of oil recovery rate is of great importance for carbon dioxide enhanced oil recovery (CO_2EOR), and fundamental mechanism of Oil/CO_2 two-phase flow in porous media is need to be clarified. However, flow process is still not completely understood because of the difficluty of experimental flow visualization. In this study, CO_2 was injected into a packed bed of silica sand that was saturated by decane, and two-phase flow process of decane/CO_2 under high pressure was visualized by using micro-focus X-Ray CT. As the result, three-dimensional behavior of the CO_2 distribution was clearly observed.

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Photovoltaic industries nowadays demand the flexible solar cell that is composed of thin silicon sheet, since the solar cell needs to be installed on the complex geometry. The new process to produce thin silicon sheet was developed by means of low melting temperature alloy that is pulled horizontally from a container and is solidified in air. As a result of the experiments and numerical simulations, the control of static pressure of the liquid metal in the container turned out to be needed in order to produce thin and uniform metal plate.

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In this paper, the characteristics of phase change materials employed in the warm temperature about 60-90 ℃ using a solar heat utilization, repeal heat and so on are discussed by the experimental values. In the experiment, sodium phosphate dibasic heptahydrate, Polyethylene glycol 4000, Calcium chloride dihydrate, Dodecanoic acid and sodium acetate trihydrate are chosen as a sample. A melting point and a latent heat are measured by a differential scanning calorimeter (DSC). for sodium acetate trihydrate, the relation between a mass percent of a sodium acetate and a latent heat are discussed in the range from about 40 wt% to 65 wt%.

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Ice adhesion to a cooling solid surface often occurs in many situations. And it causes many serious problems accompanied by economic losses. Thus, it is urgent to clarify a mechanism of ice adhesion to the cooling solid surface. And, in order to clarify the mechanism essentially, it is necessary to investigate it in nano-micro scale field. Thus, one of authors developed the measurement method of ice adhesion force in nano-micro scale fiel by SPM. In this paper, ice adhesion force was measured based on the method, varying surface temperatures of the cooling solid, the correlation between the ice adhesion force and surface temperature was clarified.

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This study was carried out to study the mechanisms of freezing-point depression and re-crystallization in the freezing and thawing of living tissues. We used a capillary tube and micro-channel chip as the tissue models, and the experiments were conducted by directional solidification method. The experiments of the freezing process showed the relationship between the parition coefficeint and the initial concentration of NaCl solution. From the observation of the melting process, there is a possibility that re-crystallization occurs depending on the solute concentration and the injected volume of water.

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As one of typical formation methods of ice slurry, there is a harvest method where ice growing on a cooling solid surface is scraped by a scraper. This method has a merit that consideration of ice adhesion to the cooling solid surface is not required. However, it can be supposed that a scraping force of the formed ice depends on ice structure strongly. In this paper, the correlations among the controlled initial crystal orientation, initial freezing layer and ice structure were clarified, and then, apossibility of control of the scraping force was also clarified based on the correlations.

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In order to establish measurement method of effective thermal conductivity of specimens such as isotropic electrically conductive adhesives for use electronic equipment, steady state comparative-longitudinal heat flow method using cartridge type specimens have been developed. This method needs long time to get some temperature dependent thermal conductivities by waiting several times to get some steady state conditions. We have studied an improved method nnamed quasi-steady state comparative longitudinal heat flow method in which temperature dependency of the thermal conductivity can be obtained by only one time heating. We demonstrated the possibility to obtain the temperature dependency of the thermal conductivity of the specimen by numerical simulation using two-dimensional transient heat conduction model. The error of the thermal conductivity obtained by this quasi-steady method using quasi-steady condition was less than 2%.

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We have been developing an in-plain thermal conductivity measuring method of flat plate specimen such as printed wiring board (PWB) by straight fin temperature fitting method. We applied one point radiation thermometer axially moving automatically for measuring the axial temperature distribution of the speciment. From thr experimental investigation, we obtained the following conclusions. (1) By applying the temperature fitting to the range of above 5K temperature rise, the in-plane thermal conductivity of the specimen was obtained within 10% dispersion under the condition of the fin efficiency of 0.2〜0.85 in spite of temperature fluctuation of ±1K of one point radiation thermometer. (2) By using mean heat transfer conductivity of the specimen was obtained within 10 % dispersion under fin efficiency lower than 0.2.

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This paper presents a measurement of high thermal conductive materials such as graphite sheet and pitch-based carbon fiber reinforced plastics (CFRPs) using a laser-spot heating method. Temperature dependence and anisotropy distribution were obtained by using this method. The test results showed large value of high thermal conductivity of a graphite sheet. Large anisotropy of unidirectional CFRP was also observed.

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Theoretical study is carried out to investigate the effects of boundary conditions on the evaluation of the effective thermal conductivity of composite boards. The board is a simplified model of an electronic wiring board and consists of two elements, a via and a dielectric, having high and low thermal conductivities. Two types of boundary conditions, namely the heating/cooling at uniform temperatures (Case 1) and the heating/cooling through reference rods (Case 2) are applied, and the effective thermal conductivity of the board is evaluated. From the numerical results, it is found that the heat flow inside the reference rods is not uniform near the board, and consequently the effective thermal conductivity of Case 2 is smaller than that of Case 1.

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Effective thermal conductivities in thickness and in-plane directions of a printed circuit board (PCB) with highly anisotropic heat transfer nature are quite important to perform a rational thermal design of electronic equipment. Experimental study has been conducted by applying a simple evaluation method of the thermal conductivity. In this study, thermal conductivities of the glass epoxy board annd Bakelite board in in-plane direction have been evaluated by measuring the temperature distribution of the board surface by using an infrared thermometer.

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This paper describes transient heat conduction analysis for microprocessor silicon die temperature prediction using one-dimensional thermal network. Temperature gradient prediction between two different-sized objects along heat conduction paths is one of key factors to obtain calculation result with practical accuracy in transient state. This paper refers it as thermal spreading resistance and tries to investigate transient behavior of the temperature gradient between thermal grease and heat sink base by onducting three-dimensional heat conduction simulation.

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3D devices which contain two or more chips stacked vertically and connected by through silicon via (TSV) will be required for high performance computer (HPC) systems. However heat dissipation is a critical issue because 3D devices are difficult to cool the lower layer chips. In this paper, cooling behavior of 3D devices mounted on printed circuit board (PCB) with thermal vias area is studied. It is confirmed that cooling from substrate side is effective to cool the lower layer chips in 3D devices.

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This paper describes how to evaluate the measurement results of in-plane thermal conductiity of Printed Circuit Board (PCB) without Computational Fluid Dynamics (CFD) analysis. Previously, a measurement method of in-plane effective thermal conductivity of PCB by using one-dimensional thermal resistance measurement results include both out-of-plane and in-plane effective thermal conductivities, one more step is measurement results, CFD analysis was employed. In this paper, theoretically constructed estimate equation is employed and the possibility of the equation is discussed.

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The thermal conductivity of such materials as metal, grease and rubber can be evaluated by setting them between two reference rods whose thermal conductivity is known. In this measurement, not only the contact interface temperature between the reference rod and the inserted material but also the heat transfer rate flowing through the material can be measured simultaneously. In this study, based on the physical model corresponding to the measuring system, a series of numerical analysis have been performed in order to clarify the heat flow in the system, and further the influence of the heat flow on the thermal conductivity measurement of the material has been investigated.

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A heat spreader has been widely used for thermal management of electronic systems. It is placed between a small heat source and a large heat sink to enhance the heat transfer from the former to the latter. This paper describes the theoretical study on 45° spreading nagle of the heat spreader. This angle is employed by thermal designers, but its validity has not been verified. Therefore, three-dimensional numerical analysis is performed, and the heat transfer characteristics inside the heat spreader are visualized. Form the numerical results, which are obtained by changing the design parameters of the heat spreader, the applicability of 45° spreading angle is confirmed.

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This paper describes thermal and electrical properties of Si power MOSFET. The problem of hot spot in submicron scla Si MOSFET has been widely known. Recently, Si power MOSFET is key device in a lot of area, for example car electronics. In Si power MOSFET, high voltage is applied and high current is generated. Therefore, heat generation becomes higher and thermal management is important. In this paper, thermal and electrical properties of Si power MOSFET is evaluated with Electro-Thermal Analysis and fundamental heat generation phenomenon of Si power MOSFET is discussed. Further, generation of hot spot is also discussed.

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Three dimensional numerical analysis is utilized for thermal design of electronic devices. In this calculation, heat productions of electronic component are needed for input values, and they have an important consequence for prediction accuracy. But, it is often the case that the values are imprecision, because it is not well defined to measure or calculate the values at the moment. We developed a measurement method that is used a water cooled heatsink and thermocouples. Heat productions are estimated by direct measurement of the water temperature and flux, and it is executed in the state that electronic circuit is operated.

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We describe a study of the cooling device based on the electrocaloric effect (ECE) in multi-layer ceramic capacitor (MLC). The ECE causes increasing and decreasing temperature of a dielectric material by changing the electric field. To separate heating and cooling sequence of ECE, the heat pipe used as the thermal diode was combined with MLCs. This device demonstrated that the temperature of MLC was dropped 0.43 degrees by applying 71.5 MV/m at 0.1 Hz.

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Laser processing and laser measurement has attracted attention from a vaiety of fields with the recent advances in laser technology. In particular, short pulse laser is useful in microfabrication and high-speed measurement, and further research of transient lens effect is expected. We have proposed a temporal and spatial pulse shaping technique with an effective refractive index change due to ransient lens effect. However, sub-nanosecond time scale change in refractive index of the transient lens effect has not been clear. In this study, we have established a method of time-resolved measurement of the refractive index change caused by the transient lens effect and measured tub-nanosecond time scale change in refractive index of the transient lens effect.

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Preparation of water nano-droplet or silver nanoparticle/nanowire dispersed perflurocarbon 3M Novec HFC-7100 (FC) base nanofluid has been developed for heat transfer enhanement of FC fluid. The good dispersion stability of water-droplet dispersed FC nanofluid was maintained for over 6 months by addition of organic additives into HFC-7100, and the water droplet diameters of FC nanofluid were around 100-150 nm, which can be controlled of additives/water molar ratio. Also, silver nanoparticle dispersed HFE-7x00 base FC nanofluid can be obrained by using surface modification technique. It was found that thermal conductivities of obtained water nano-droplet dispersed FC-nanofluids were increased around 10 % comparing with the base fluids. Heat transfer enhancement could be achieved by using the FC nanofluid as single-phase heat transfer cooling fluid for mock lack-mount PC server liquid cooling.

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For the passive thermal management of power devices such as IGBT, GTO et al., plate-type heat pipes, 4.0mm x 40mm x 375mm, of maximum heat transport capability, Qmax, of the order of 100W, have been developed. The thermal performance in both horizontal and vertical orientations was experimentally evaluated, and outstanding thermal performance of Qmax up to 600W in the vertical orientation and thermal resistance as low as 0.01K/W were confirmed. The plate-type heat pipes were then applied to the thermal management systems for a CPU in a 1-U server and for SiC power JFET, and stable and satisfactory cooling performance of the heat pipes for the electronics devices was demonstrated.

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In the present experimental and theoretical study, main purpose is to find out the performance limiting factors of thin heat pipe with new fiber wick structure. As the limiting factors we mainly focused on Cu pipe structure, wettability, capillary force, liquid flow area, vapor flow area and mechanical damage. In this paper, relation between the thermal performance of heat pipes with different thickness and width are showed. With the effective length of heat pipe is 125mm; maximum heat transfer capability of 0.8, 1.2, 1.5 and 2.0mm thick heat pipes are 7W, 15W, 25W, 34W and 42W respectively. Also, the theoretically achieved relation between the total pressure drop, liquid flow area and vapor flow area with different Cu pipe structure is shown.

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This report presents results of an experimental investigation on the heat transfer characteristics of a Flat-plate thermosyphon. In this study, it is intended to achieve further performance advance of the thermosyphon, several tests were performed to assess the effects of the filling ratios and the inner structure at a vertical orientation. As the result, it was found that inner structure was effective for increase of heat transfer characteristics of the evaporation section. It was also shown that the heat transfer characteristics decreased when the accumulated of the working fluid in condensation section.

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The Sano-Nakayama membrane transport model for the analysis of a countercurrent dialyzer system has been extended to describe the concentration polarization phenomena associated with hollow fiber reverse osmosis desalination systems. A set of the governing equations based on VAT, namely, the continuity, momentum and concentration equations for the brine, permeate and membrane has been derived. A series of two-dimensional numerical simulations were performed using the present model. The numerical results are found to agree well with the experimental data reported by Sekino. Furthermore, a graphical presentation is proposed for determining the operating parameters, namely, the feed pressure and pumping power.

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Carbon dioxide injected into the aquifer would be trapped by capillarity in porous rocks. We simulated two-fluid-phase flow in porous media by means of a Lattice-Boltzmann Method to examine the influence properties of porous media gave on gas trapping. Simulation results show three trapping mechanisms and the saturation agree with the experimental results. Residual gas saturation tends to increase with the reducing pore throat radius of porous media but does not affected by the coordination number.

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A porous media model has been adopted to predict local urban climatological phenomena associated with sea and land winds. Buildings in the urban area are modeled as a collection of porous blocks of prescribed permeability and porosity. The numerical results reveal that the present model coupled with a turbulence model is capable of capturing general characteristics in the sea and land winds, and that the artificial heat generation should be taken into account for accurate prediction of the wind peak levels.

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In the article, we conducted lattice Boltzmann simulation (LBM) to investigate microscopic two-phase flow behaviors in homogeneous sphere packing medium and heterogeneous porous medium. A two-phase LBM model showed its feasibility to independently investigate effects of contact angle and surface tension on flow behaviors It was observed that liquid water invasion was affected by hydrophobicity of the surface wall in the medium and this was attributed to meniscus formed by liquid and gas phases.

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As is well known, a highly porous medium has a structure of slim mesh frames and has a porosity of about 90%. So far, this kind of porous medium has been often used to control reacting flows, heat transfer rate and so on. The purpose of this study is to clarify the heat transfer characteristics of the system with a highly porous medium. From a series of experiments, the following findings have been obtained: The highly porous medium is promising as a good heat transfer material. The mode of the heat transfer using a highly porous medium is mainly heat conduction under the present conditions.

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A sub-channels-inserted porous evaporator is proposed as a heat sink of future power electronic devices with a heat load exceeding 300W/cm^2. This porous heat sink is attached onto the backside of a heating chip and removes the heat by evaporating cooling liquid passing through the porous medium against the heat flow. The results show that the heat transfer performance of a copper-particles-sintered porous heat sink with the sub-channels succeed in achieving a heat transfer coefficient of 9.00×104 W/m^2/K at a wall superheat of 91K against a heat flux of 816W/cm^2 and that a targeted heat flux of 300W/cm^2 is possible enough to cool at the wall superheat less than 50K.

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There are several methods for heat transfer enhancement. For example, one can attach various fins on the heat-transfer surface, process the surface roughly, insert twisted tape, and so on. These methods increase the heat-transfer coefficient or area by manufacturing changes to the heat transfer surface. However, it is necessary to consider the reduction of structural strength for attaching of fins on the heat transfer surface. In this study, the effect of heat transfer enhancement by inserting porous metal intermittently was studied and the pressure drop by using porous material was also evaluated.

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