© 2019 Elsevier Ltd In cryosurgery, downscaling of cryoprobes is important to minimize surgical invasion. In this study, a set of analytical solutions to the freezing phenomenon around a cryoprobe in a dimensionless form is derived and the general trend is discussed to clarify the relationship between the freezing ability of a biological tissue and the cooling power of a cryoprobe. A one-dimensional axisymmetric model in the steady-state condition is considered. The relationship between the size of the frozen region, fluid temperature in the cryoprobe, and heat transfer coefficient on the wall of the cryoprobe in the dimensional form is derived under the condition mentioned above. The fluid temperature and heat transfer coefficient are eliminated from the solutions by introducing the steady-state cryoprobe surface temperature. This transformation indicates that the steady-state surface temperature directly affects the size of the frozen region and combination of fluid temperature and heat transfer coefficient occurs, which has the same cooling effect. The derived solutions are transformed into a dimensionless form using the characteristic length of bioheat transfer and normalizing the temperature distribution in an unfrozen tissue. The applicability of these analytical solutions is evaluated by comparing them with numerical simulation results from existing studies. The dimensionless solutions describe the general trend of the relationship between the frozen region and the cooling power of a cryoprobe, which is independent of the type of organ, fluid temperature, and heat transfer coefficient. Finally, the concept of freezing limit is established using the derived solutions. The freezing limit describes the minimum requirements to freeze a tissue, and it can be used as guideline to design future downscaled cryoprobes with a suitable cooling mechanism.

In this study, the effect of the structure of an ultrafine cryoprobe on its cooling performance was evaluated experimentally and numerically. To clarify the thermodynamic characteristics of the refrigerant in the ultrafine cryoprobe, three ultrafine cryoprobes with different dimensions were manufactured. Additionally, a phase change flow model was developed to estimate the refrigerant condition in a microchannel and evaluate the cooling characteristics of an ultrafine cryoprobe. For validating the numerical model, the results were compared with experimental data and a suitable empirical correlation for a two-phase pressure drop was determined. By calculating the refrigerant condition in an ultrafine cryoprobe, it is clarified that large pressure drops occur in the inner tubes and the refrigerant becomes subcooled owing to heat exchange between the flows in the inner and outer tubes. The temperature differences for three different cryoprobes are reproduced by the developed model. By changing the dimensions of the tubes comprising the ultrafine cryoprobes in the calculation, the lowest temperature can be determined. Additionally, freezing experiments are conducted, and the importance of temperature and vapor quality in ultrafine cryoprobes is represented in the time variation of the frozen region.

The objectives of this study were to establish a theoretical model of the phase change heat transfer in a microchannel and to investigate the possibility of cooling under higher heat flux than the critical heat flux for nucleate boiling. A bubble expansion model including transient variation of the liquid film thickness was proposed. The heat transfer coefficient and wall superheat were calculated by proposed model. The validity of this model was evaluated by using cited experimental data. It was confirmed that the bubble length derived by this model was in good agreement with that data. In order to evaluate the heat transfer regime in a microchannel, the minimum wall superheat to initiate nucleate boiling was introduced, and the conditions to achieve perfect evaporative heat transfer in a microchannel under the critical heat flux were derived. The diameter of the microchannel where perfect evaporative heat transfer occurs is called the "boiling limit diameter". The boiling limit diameters of various fluids were calculated. The results clarified the influence of the surface tension on the phase change heat transfer in a microchannel. Furthermore, this result also indicated the possibility of high heat flux cooling with perfect evaporative heat transfer in a microchannel.

Boiling heat transfer experiment to develop an ultrafine cryoprobe was conducted The flow passage of the experimental apparatus simulated the structure of the ultrafine cryoprobe which is the co-axial double tube The effects of the difference from the structure on the boiling phenomena were evaluated Water under the low pressure condition was used as working fluid A glass tube was used for the outer tube to visualize the phenomena and its inner diameter was 1 2 mm The emission of small bubbles from the Inner tube in the glass tube was observed Furthermore the temperature measurement with the heat flux supplied on the needle surface was conducted The relationship between the needle surface temperature and the heat flux clarified that the needle surface temperature of smaller inner tube becomes lower This fact indicates that the pressure drop of the inner tube or the state of water at the exit of the inner tube is important for the ultrafine cryoprobe (C) 2010 Elsevier Inc All rights reserved

The derivation and application of the general characteristics of bioheat transfer for medical applications are shown in this paper. Two general bioheat transfer characteristics are derived from solutions of one-dimensional Pennes' bioheat transfer equation: steady-state thermal penetration depth, which is the deepest depth where the heat effect reaches: and time to reach steady-state, which represents the amount of time necessary for temperature distribution to converge to a steady-state. All results are described by dimensionless form; therefore, these results provide information on temperature distribution in biological tissue for various thermal therapies by transforming to dimension form. (C) 2009 Elsevier Ltd. All rights reserved.

The importance of modeling the radiative absorption in an environment with a high concentration of water vapor, such as inside a sauna, was studied through numerical analyses and fieldwork. Radiative heat transfer analysis using the discrete ordinate method (DOM) was performed using OpenFOAM software to evaluate the influence of thermal radiation inside a sauna. In a high-temperature environment, such as a sauna, the effect of radiation heat transfer in the surrounding medium gradually increases. Therefore, the effects of the medium cannot be ignored. A full-spectrum k-distribution (FSK) was adopted to model the radiative absorption of the medium, which was composed of carbon dioxide and water vapor. The mean radiant temperature (MRT) was also determined using numerical simulations to compare the results with those measured directly using a globe thermometer. The measured MRT was lower than the air temperature because of radiative cooling by the sur-roundings. To evaluate the quality of the radiative absorption model, the MRT obtained using the transparent gas and FSK methods were compared. When the distance from the cooling front window was approximately 4 m, the FSK method improved the prediction of MRT by approximately 1 degrees C when compared with the transparent gas method, which is the conventional method. The FSK method improved the MRT prediction from the conventional method by approximately 27% in terms of the Root Mean Square Error. This result indicates the importance of modeling the MRT by considering radiative absorption in the presence of high water vapor pressure.

Abstract An experimental study of cavitating flow on a heated NACA0015 hydrofoil was conducted in a cavitation tunnel to investigate the influence of the hydrofoil surface temperature on the cavitating flow. The cavitation behavior under different heating conditions was examined using high-speed video, and an image processing method was used to obtain the periodic characteristics of the cavitating flow. The results revealed that attached sheet cavitation and supercavitation occurred on both heated and unheated hydrofoils. However, sheet-cloud cavitation was observed only on the unheated hydrofoil, whereas transient cavitation was observed only on the heated hydrofoil. Transient cavitation also exhibited periodic growth/collapse behavior; however, there was no shedding of a large vapor cloud. Moreover, with a further increase in the hydrofoil surface temperature, transient cavitation turned into open-type cavitation. The cavitating flow exhibited a quasi-steady cavity length with an open cavity closure. It was considered that the surface temperature promoted vapor generation at the cavity leading edge, which enlarged the vapor-filled fore part of the sheet cavity. This enlarged sheet cavity prevented the reentrant flow from moving upstream and thus turned the cavity closure into an open type. Once the cavity closure turned into an open type, the local disturbance led to a smaller adverse pressure gradient, which was not sufficiently strong to create a reentrant flow. In this case, if the vapor generation at the cavity leading edge was sufficiently large to reach a balance with vapor condensation at the open cavity closure, the cavity would be steady.

The thermodynamic suppression effect of cavitation arising in a NACA0015 single hydrofoil is experimentally investigated in water at mainstream temperatures of T1 = 20 C to 140 C in the present study. The cavity length at T1 = 140 C is shorter than that at T1 = 20 C at a constant cavitation number for all cavity patterns from inception to supercavitation. On the other hand, the cavity length at T1 = 80 C is slightly shorter than that at 20 C in a certain region in which unsteady sheet-cloud cavitation occurs. This indicates that the thermodynamic suppression effect appears easily in unsteady cavitation. In addition, the temperature reduction inside cavities in water is accurately measured using thermistors, which are inserted from the sidewall directly into the cavity. The temperature measurement is performed at a mainstream temperature of less than 80 C due to limitation of calibration for the sensor. The temperature reduction at 140 C is then predicted from the measured cavity length. It is shown that the temperature reduction inside the cavity is approximately DT = 0.3 C at T1 = 80 C and DT = 0.05 C at T1 = 20 C under supercavitation conditions. The predicted temperature reduction inside the cavity is DT = 1.1 K at T1 = 140 C under supercavitation conditions. Finally, Fruman’s prediction equation for DT is examined by fitting to the measured and predicted DT values with assuming a volume coefficient of evaporation CQ as a fitting parameter.

A piecewise linear model of phytoplankton growth in the presence of a convective flow has been proposed in the paper. The model, in one-dimensional formulation, admits a stable autowave solution, propagating with a certain critical minimum velocity. The main purpose of the work is to study the features of the phytoplankton front propagation in the presence of vortex flow. The vortex flow represents chain of two-dimensional vortices described by the Taylor-Green solution of incompressible Navier-Stokes equations. Different regimes of wave propagation are revealed depending on the intensity of the vortex flow and the model parameters. In particular, the wobbling, zigzag, and jumping regimes are found if the velocity of convective flow is less or comparable, exceeds, and is much greater than the front propagation speed in still media, respectively. The front propagation velocity is characterized by definite types of dependence on the flow intensity in different regimes.

Cavitation is a phenomenon that degrades the performance of fluid machinery, whereas the thermodynamic self-suppression effect of cavitation is prominent in pumps transporting cryogenic fluids because the effect suppresses cavity development. The thermodynamic self-suppression effect is caused by the temperature decreasing inside the cavity by the evaporation and the reduction of saturation pressure inside the cavity; therefore, the cavity temperature is essential to understand the thermodynamic self-suppression effect. The temperature measurement inside the cavity has been limited in the quasi-steady cavitation because it is difficult to accommodate the fast responsiveness of a temperature sensor to respond to the temperature variation of unsteady cavitating flow varying from 10–100 Hz. This study aims to develop the estimation method for the cavity temperature from unsteady temperature response, visualized cavity image, and lumped capacitance model, which is applicable even if the responsiveness of the sensor cannot be increased. The temperature in the unsteady cavitating flow of water at 100 °C and 10 m/s with various cavitation numbers were measured, although the temperature responsiveness was insufficient for the unsteadiness of the cavity. In addition, the phase index, which is the parameter to distinguish the fluid phase around the thermistor, was determined from high-speed video images. The cavity temperature was estimated using the lumped capacitance model with the time variation of the temperature and phase index. As the result of the estimation, the temperature fluctuation of the thermistor and the estimated temperature fluctuation were in general agreement by adjusting the cavity temperature and heat transfer coefficient in the estimation equation. The estimated cavity temperature was smaller than the averaged value and the minimum value of the temperature fluctuation of the thermistor at each cavitation number. Additionally, the estimated heat transfer coefficient in the cavity is of nearly the same order of magnitude as that in the liquid phase

We aimed to derive a phase diagram in the parameter space of wall temperature Tw and Weber number We for the spreading behaviors of water drops impacting a heated sapphire plate. Focusing on hydrodynamic instabilities, we performed drop impact experiments to investigate spreading behaviors with varying wall temperatures (Tw = 60 to 150 °C) and Weber numbers (We = 29.5 to 443) using high-speed infrared (IR) imaging. A phase diagram was established accommodating three different regimes: the gentle spreading regime, rim instability regime, and contact-line instability regime. The gentle spreading regime occurs under low-We and low-Tw conditions. In this regime, the drop spreads while maintaining a round shape with no perturbations. With an increasing Weber number at any wall temperature, the spreading behavior undergoes a transition to the rim instability regime, where a finger like perturbation can be observed along the lamella rim of the spreading drop. For low-We and high-Tw conditions, instead of rim instability, we observed a transition to the contact-line instability regime, where finger like perturbations form along the contact line. Additionally, we explored the temperature dependency of the maximum spreading ratio, dimensionless perimeters, and number of fingers for the contact-line instability and rim instability regimes. The experimental results indicated that intense evaporation around the contact line has a significant impact on the growth of the observed hydrodynamic instabilities, leading to changes in spreading behaviors. To the best of our knowledge, ours is the first study to observe the contact line instability induced by thermal effects. Considering the occurrence of contact line instability only at high Tw values, we expect that intense evaporation around the contact line is a key factor in the underlying mechanism of contact line instability.

Recently, selective heating techniques by laser therapy have been proposed. Among them, laser therapy adopting metallic nanoparticles has garnered att ention. By injecting metallic nanoparticles inside a tissue, high absorption can be achieved by the local surface plasmonic resonance at the surface of the nanoparticle. In particular, gold nanorods exhibit signifi cantly high resonance against laser and their eff ectiveness has been investigated experimentally. However, the modeling of laser therapy by gold nanorods is limited, and a quantitative numerical simulation is required to further investigate the possibility of eff ective heating by gold nanorods. To investigate the eff ectiveness of selective heating by laser therapy with gold nanorods, a three-dimensional calculation of laser therapy is performed in this study. To model the thermal conduction and propagation of laser inside a tissue, the Pennes bio-heat transfer equation is applied. The radiative heat transfer is calculated using the radiation element method. The dispersion eff ect of gold nanorod injection is considered. Comparing the thermal damage between gold nanorod injection and noninjection cases, the performance of selective heating by gold nanorods is evaluated. Furthermore, the eff ect of gold nanorod injection location on the thermal damage is discussed. Numerical calculation results indicate that gold nanorod injection enables selective heating against the target as well as noninvasive heating on the tissue surface. Furthermore, the heating depth can be controlled by changing the injection location appropriately.

© 2020 Author(s). Composed of methane gas and cage-like water molecules, methane hydrate is expected to have innovative engineering applications, such as gas transportation. In this study, a methane hydrate decomposition interface is visualized qualitatively, and the decomposition rate is discussed. To clarify the decomposition mechanism, consideration is given to the dynamic decomposition interface and the variation of the decomposition rate. In the present experiment, methane hydrate is formed around a water droplet and decomposed by depressurization in the gas phase, the dynamic variation of the decomposition interface is observed precisely using a high-resolution camera, and three different depressurization conditions are used to confirm the interfacial change. It is found that the decomposition rate and dynamic shape change of the decomposition interface depend on the difference between the equilibrium pressure and that of the gas phase. In addition, the decomposition time is discussed using the decomposition model, and it is estimated that the present experimental decomposition rate corresponds to a lower activation energy for decomposition compared with that of the model by other authors. It is assumed that the decomposition proceeds under nearly reaction-limited conditions. Additionally, the interfacial deformation and collapse are observed in the case of pressure reduction near the equilibrium pressure, and validation is provided by a numerical simulation considering the heat and mass transfer near the interface. The numerical results suggest that the decomposition is affected by the interfacial configuration and the nearby temperature and concentration distributions.

© 2019 The transient heat and mass transfer near a methane hydrate decomposition interface were quantitatively measured to evaluate the rate-determining factors of dissociation with high spatiotemporal resolution. In this study, we proposed a measurement system for the dissociation phenomenon near the hydrate interface, and the rate-determining step of the dissociation phenomenon was discussed in terms of the experimental results and numerical simulation using a dissociation model. The hydrate was generated around a water-like film under temperature of 274 K and pressure of 4.8 MPa of mixed gas comprising methane and helium in a temperature and pressure controlled system. A high-speed phase-shifting interferometer was used to measure the interfacial transient heat and mass transfer. In the present study, transient variations in the optical path length difference caused by the variation in the density field near the hydrate interface were visualized with temporal and spatial resolutions of 1 ms and 3.88 μm/pixel, respectively. The measured values were compared with the results of numerical simulations, assuming that the mass flux of methane was a function of the activation energy of dissociation. The comparison showed that the experimentally measured values exhibited similar tendency as the values estimated using the activation energy of approximately 60,000 J/mol. This result was also confirmed from the interface shape variation of the hydrate. Finally, the dissociation phenomenon of the hydrate was estimated as the rate-determining step of the reaction by using our special interferometer system.

<p>To evaluate the frictional heating effect during ski gliding by temperature measurement, a temperature measurement system was developed and evaluated numerically and experimentally. The portable temperature measurement system with high temperature resolution and accuracy consisted of thermistors and a portable logger with a 24-bit A–D convertor. The thermistors were inserted in a hole in the ski board with thermal conductive adhesive. By using numerical simulation, the difference between the interface temperature and the averaged temperature in the sensing region was evaluated. The temperature difference was proportional to the value of frictional heat generation, and the maximum difference in the experimental range in this study was 0.17 K. To test the developed system, a gliding experiment was conducted at Shinjo Cryospheric Environment Laboratory. Three thermistors were installed in the ski board, and a moving object was constructed on the ski. By pulling the moving object with a guide wire, the moving object was glided, and the interfacial temperature was recorded. In the case of a total weight of 54 kg, which was near the optimal weight, the thermistor installed near the heel position had a large increment of temperature. In addition, similar temperature increments were observed during the acceleration phase of the moving object. After the acceleration phase, the gradient of the temperature increment changed. It was inferred that the variation of gradient was affected by the variation of the force balance on the moving object. This suggests that the local contact condition and friction might be estimated through temperature measurement.</p>

© 2019, The Author(s). Melanoma is an aggressive skin cancer that originates from melanocytes and, especially in the case of early-stage melanoma, is distributed adjacent to the epidermis and superficial dermis. Although early-stage melanoma can be distinguished from benign nevus via a dermoscopy, it is difficult to distinguish invasive melanoma in its early stages from in situ melanoma. Because invasive melanoma must undergo a sentinel lymph node biopsy to be diagnosed, a non-invasive method to detect the micro-invasion of early-stage melanoma is needed for dermato-oncologists. This paper proposes a novel quantitative melanoma identification method based on accurate measurements of thermal conductivity using a pen-shaped device. This method requires skin temperature data for one minute to determine the effective thermal conductivity of the skin, allowing it to distinguish melanoma lesions from healthy skin. Results suggest that effective thermal conductivity was negative for in situ melanoma. However, in accordance with tumour progression, effective thermal conductivity was larger in invasive melanoma. The proposed thermal conductivity measurement is a novel tool that detects the micro-invasion of melanoma.

In industrial applications, cryogenic liquids are sometimes used as the working fluid of fluid machineries. In those fluids, the thermodynamic suppression effect of cavitation, which is normally ignored in water at room temperature, becomes obvious. When evaporation occurs in the cavitation region, the heat is supplied from the surrounding liquid. Hence, the liquid temperature is decreased, and cavitation is suppressed due to the decrease in saturated vapor pressure. Therefore, the performance of the fluid machinery can be improved. Computational fluid dynamics, which involves the use of a homogeneous model coupled with a thermal transport equation, is a powerful tool for the prediction of cavitation under thermodynamic effects. In this study, a thermodynamic model for a homogeneous model is introduced. In this model, the source term related to the latent heat of phase change appears explicitly, and the degree of heat transfer rate for evaporation and condensation can be adjusted separately to suit the homogeneous model. Our simplified thermodynamic model coupled with the Merkle cavitation model was validated for cryogenic cavitation on a two-dimensional (2D) quarter hydrofoil. The results obtained during the validation showed good agreement (in both pressure and temperature profiles) with the experimental data and were better than existing numerical results obtained by other researchers.

© 2019 Elsevier Ltd Greenhouses are built in hot climates to provide a cool environment suitable for growing out of season crops. Their temperature is usually controlled by utilizing air conditioning systems and shading the transparent cover material in peak sun hours. A new method to keep a cool greenhouse, and reduce energy consumption is proposed in this study. Using a new approach for pigmented coatings, that would reflect incident solar radiation in the infrared wavelengths (NIR), and allows the shorter visible wavelengths (VIS) to be transmitted. It is possible to reduce the heat gain inside the green house by radiation while keeping the useful wavelengths necessary for photosynthesis. A series of numerical calculations is performed, modeling the radiation transfer in the pigmented coating using the Radiation Element Method by Ray Emission Model (REM2). Mono dispersed particles are assumed, and Mie theory is used to estimate the radiative scattering properties of the particles. Different materials are studied as pigments and compared over a range of particle sizes and volume fractions. The calculated spectral reflectance curves were compared with experimentally derived ones of TiO2 pigmented coating, they differed in values but showed the same tendency. An optimization parameter is proposed and used to compare the different materials and parameters. Diamond particles are found to be the most appropriate candidate for the desired application, giving a high transmittance in the VIS region and high reflectance in the NIR region.

© 2019 Elsevier Ltd In this study, our cavitation model was employed and coupled with our simplified thermodynamic model to simulate the hydrogen cavitating flow field. Cavitation experiments on a 2D tapered hydrofoil in LH2 were selected to validate our model. The numerical solutions of the temperature and pressure distributions along the hydrofoil were compared and examined. The sensibility of the numerical solution of cavitation regarding to the cavitation empirical phase change constants was investigated. The empirical parameter for evaporation and condensation were corrected for hydrogen with comparable accuracy to experimental data. Additionally, corresponding of the degree of thermodynamic effect in hydrogen cavitation was discussed based on two types of thermodynamic parameter. In that, the temperature depression inside the cavity in both existing experimental data and present numerical result did not increase according to the increase in nondimensional thermodynamic parameter ∑*, which includes the thermal diffusivity with laminar boundary layer implicitly assumed. This indicates that turbulent effect has to be considered in the duration time of thermodynamic effect for a flow with a high Reynolds number, such as LH2 flow.

© 2018 Elsevier Ltd In this study, the radiation effects on the temperature field and perturbation of the thermal boundary layer of natural convection for gas were evaluated by an interferometer. The natural convection investigated in this study was that of a cavity, which had differentially heated vertical walls, surrounded by adiabatic walls. The target Rayleigh number was of the order of 108–109. By using the interferometer adopted in a phase-shifting technique, surface and gas radiation effects were evaluated. To compare the experimental results, a numerical calculation was also conducted using a large-eddy simulation coupled with radiative heat transfer. By varying the emissivity of the adiabatic walls while maintaining the emissivity of the isothermal walls, the surface radiation effect on the natural convection was analyzed. To neglect the gas radiation effect, air was used as the working fluid. When the adiabatic walls were black-body surfaces, the temperature difference around the adiabatic walls was higher than that of the reflective surface as a result of the optical path difference. From this result, the high temperature difference due to the surface radiation effect was confirmed. To investigate the gas radiation effect on natural convection, trifluoromethane gas, which has significant radiative absorption, was used as a working fluid. By evaluating the interference fringe by the interferometer, the wave motion of the thermal boundary layer around the heated and adiabatic walls was visualized. Comparing the numerical calculation results (when varying the calculation conditions) revealed that the wave motion and turbulence boundary layer around the heated and adiabatic walls were caused by the gas radiation effect.

© 2019 Elsevier Ltd Methane hydrate (MH) is regarded as one of the potential and substantial energy resources. The permeability of hydrate-bearing layer (HBL) can potentially influence heat and mass transfer during hydrate dissociation by depressurization. In this study, a reservoir-scale MH model was constructed to investigate the effect of permeability anisotropy on gas production behaviors by depressurization with a horizontal well. The numerical results indicate that permeability anisotropy can initially negatively influence the hydrate dissociation and gas production, but later promote the process. Meanwhile, permeability anisotropy can lead to an increase of ratio of gas phase to total production and gas-to-water ratio during long-term gas production. Moreover, permeability anisotropy can enhance the horizontal flow and the dissociation reaction in the top part of the HBL for a long period, but also leads to an increase of accumulated free gas in the reservoir. Furthermore, the comparison of horizontal well production and vertical well production indicates that the horizontal well can increase the gas production by one order of magnitude than that of vertical well during a production period of 360 days, and permeability anisotropy appears to have less effect on gas production in the initial short stage when using the vertical well.

© 2019 Elsevier Ltd The combination of hydraulic fracturing and depressurization method has been proposed to enhance gas production efficiency from methane hydrate (MH) reservoirs. To evaluate the efficacy of this method, we construct a fractured MH reservoir model and investigate by means of numerical simulation the gas production behaviors under two different temperature conditions. The simulation results indicate that the combination of hydraulic fracturing and depressurization method is more efficient for gas production than the single depressurization method. For the high-temperature reservoir, the hydrate dissociation and gas production during the early depressurization stage can be significantly enhanced after fracturing, and the effect of increasing the size and permeability of the fractured zone on gas production rate is more remarkable in the early depressurization stage than in the late depressurization stage. For the low-temperature reservoir, while the improvement in hydrate dissociation and gas production by fracturing is dramatic during the entire depressurization period, the increment in total gas production is very low in absolute terms. In addition, gas production from low-temperature reservoir is very sensitive to initial temperature, and increasing the reservoir temperature can enhance the benefits of fracturing.

© 2019 Elsevier Ltd A non-imaging concentrator compound by involute and parabolic concentrator was considered in a regenerative organic Rankine cycle (ORC). The concentrator was covered by vacuumed glass tube to reduce heat loss from the absorber, and to extend the effective life-cycle of optical components. Using the non-imaging concentrator can eliminate the necessity of sun tracking system due to its large acceptance angle. A simulation was carried out for low temperature solar thermal electric generation for various working fluids including dry, isentropic and wet fluids. The results showed the best efficiency of concentrator was observed for the case of R-141b and followed by methanol, R-113, water, benzene and cyclohexane, respectively. The best overall system efficiency was seen in the case of R-141b to be 16.7%. The evaporator pressure was changed as a calculation parameter. The best improvement was obtained for water and R-141b to be 8.8% and 8.3%, respectively. R-141b has a preferable performance because of its low boiling point and can be appropriate for small scales. The increase in evaporator pressure persuades the performance improvement for the case of methanol, water and benzene. It proves that these working fluids can be used for larger scale applications with a better thermal performance.

© 2018 Three-step phase-shifting imaging ellipsometry is proposed for the dynamic measurement of a nanofilm&#039;s thickness profile in two dimensions. The designed apparatus consists of an ellipsometric optical configuration and an image-processing unit to perform phase-shifting imaging ellipsometry measurements, a key technique used to achieve dynamic and two-dimensional measurements. The uncertainties of the ellipsometric parameters ψ and Δ were evaluated based on the developed optical system and the proposed three-step phase-shifting technique. The thickness profile of a SiO2 nanofilm on a silicon substrate was measured to calibrate the proposed apparatus; results were comparable to those obtained by a commercial spectroscopic ellipsometer. The measured thickness profiles are almost flat over the area of 1.10 mm × 2.21 mm with the spatial resolutions of 1.58 and 4.62 μm in the horizontal and vertical directions, respectively. The differences of average thickness between the proposed apparatus and a commercial spectroscopic ellipsometer were less than 3 nm. Furthermore, measurement precision was validated by obtaining a standard deviation of less than 2.5 nm.

© 2018 Elsevier Ltd Many natural methane hydrate (MH) reservoirs are heterogeneous and are characterized by a layered structure. In this study, we numerically investigate gas production from a multi-layered hydrate reservoir by depressurization through a single vertical and a single horizontal well. This layered MH reservoir is constructed based on field test data at the AT1 site of the Eastern Nankai Trough in Japan, and involves three hydrate-bearing layers (HBLs): Upper HBL-1, middle HBL-2, and lower HBL-3. The simulation results indicate that the horizontal well shows a better gas production performance in comparison to the vertical well. Over a production duration of two years, the average gas production rate by using the horizontal well reached 7.3 × 104 ST m3/d, which is 5.7 times higher than that by using the vertical well. However, the gas-to-water ratio for both the vertical and horizontal well cases is low in absolute terms. Sensitivity analysis of gas production by the horizontal well indicates that both the very higher and lower levels of permeability in HBL-2 and hydrate saturation in HBL-3 are unfavorable for long-term gas production. In addition, decrease of vertical permeability in HBL-1 and HBL-3 can lead to lower gas production efficiency.

Chameleons have a diagnostic thermal protection that enables them to live under various conditions. Our developed special radiative control therefore is inspired by the chameleon thermal protection ability by imitating its two superposed layers as two pigment particles in one coating layer. One particle imitates a chameleon superficial surface for color control (visible light), and another particle imitates a deep surface to reflect solar irradiation, especially in the near-infrared region. Optical modeling allows us to optimally design the particle size and volume fraction. Experimental evaluation shows that the desired spectral reflectance, i.e., low in the VIS region and high in NIR region, can be achieved. Comparison between the measured and calculated reflectances shows that control of the particle size and dispersion/aggregation of particle cloud is important in improving the thermal-protection performance of the coating. Using our developed coating, the interior temperature decreases and the cooling load is reduced while keeping the dark tone of the object.

© 2018, Science Press. All right reserved. In recent years, the exploration and utilization of methane hydrate from permafrost and off-coast regions has become a very hot topic. Aiming at its potential as a vast energy resources in future use, the current study is focused on the low emission extraction and utilization system for oceanic methane hydrate and its economic and technological feasibility. In this study, recent real extraction tests in both China and Japan in 2017 are firstly discussed and compared, where the challenges in production period and production rate are explained. In those tests, depressurization method is used to dissociate the methane hydrate for gas production form the unconsolidated reservoir layers below the seabed. Based on the conditions of Japan, a systematic utilization system is proposed for oceanic methane hydratewhich is consisted of extraction system, power generation system, Carbon Capture and Sequestration (CCS) system and hot fluid injection system. Vertical well systems are adopted in this design and the strategic warming up process is used before depressurization extraction, so as to obtain optimal production rate of methane gas. The inclusion of CCS makes it possible to utilize methane hydrate with very low carbon emission. It is estimated that the electricity price obtained by this system can be comparable with the current civil electric price in Japan if the production rate is around 1.0×10 5 m 3 /d. Also in this study, the real extraction scenarios and possible strategies of Nankai Trough in Japan and Shenhu Area in China are re-visited and discussed by numerical models. It is found that the only depressurization or thermal stimulation method have the problems of wellbore deformation, pressure problem and energy efficiency problems, while combined strategic modes show the possibility of long-term continuous production. For the basic dissociation parameter analysis, the conditions near the equilibrium curve show higher production rate, which is due to higher initial reservoir temperature. Such results indicate the importance of heat supply inside the reservoir layer as the methane hydrate dissociation is endothermic. It is shown that with the increase of reservoir pressure, such temperature effects become more critical as the optimal initial temperature increases according to equilibrium curve. This results support the system design with strategic warming-up process in a sister well during methane hydrate extraction. In addition, the effects of reservoir layer thermal management, hot reservoir fluid flow effects on the dissociation behaviors are analyzed in this study. For vertical well analysis, the production rates under different permeability parameters show the same trend with real production, which in turn help confirm the in-lab permeability tests. Horizontal well simulation show the importance of overburden and under burden. If the confining layers are less permeable, the production rate becomes higher due to the limited intrusive water flow from the confining layers. In sum, this study summarized the advantages and disadvantages of oceanic methane hydrate extraction/utilization methods and put forward a low-carbon emission system. It is hoped that this study will contribute to the future development of both production prediction and real extraction tests.

This paper describes a non-invasive method for measurement of the effective thermal conductivity of human skin with a guard-heated thermistor probe. The guard-heated thermistor probe makes it possible to accurately measure the absolute surface temperature of a material at temperatures higher than the ambient temperature. In this study, the probe was used for a non-invasive measurement of the effective thermal conductivity of human skin by measuring skin surface temperature response for a short time. The effective thermal conductivity of human skin was measured at different body locations, such as cheeks, forearms, and heels, on five healthy volunteers. The measured values reflect the effects of multi-layered skin structure and biological processes, such as blood perfusion and metabolism beneath the skin. The results reveal a correlation between the effective thermal conductivity and the skin structure. A numerical simulation was performed to assess the effects of the epidermis thickness and the thermal conductivities of skin layers on the effective thermal conductivity of human skin. The results show that the thickness of the epidermis has a large impact on the effective thermal conductivity measured with a guard-heated thermistor probe. This is because the measured effective thermal conductivity is a function of the thermal conductivities of both the epidermis and dermis, depending on the thermal penetration depth during measurement. At locations on the body with a thicker epidermis, such as the heel, the epidermal thermal conductivity dominates over the effective thermal conductivity. At locations on the body with a thinner epidermis, such as the cheek and forearm, the dermal thermal conductivity dominates over the effective thermal conductivity. The influences of physiological conditions, such as blood perfusion beneath the skin and metabolism, on the effective thermal conductivity of human skin, were also analyzed numerically. Variations in the blood perfusion rate and metabolic heat generation rate of the dermis layer were found to have a slight impact on the effective thermal conductivity however, only the blood perfusion rate and the arterial blood temperature were found to influence the skin surface temperature.

A two-stage line-axis solar concentrator composed of parabolic and involute reflectors with tubular absorber, have been designed and experimentally analyzed for thermal applications. The concentrator is covered by evacuated glass tube for low-heat loss configuration. Due to steep angle at the end of compound parabolic reflector, the concentrator tolerates to truncate a portion of the reflector with only slight reduction on the performance. Optimum truncation level is estimated by evaluating of ray acceptance, which is described as the ratio of aperture area of the concentrator to diameter of glass cover, concentration ratio, optical performance and thermal performance. The concentrator with truncation level of 50% shows preferable performance with only 1% reduction in thermal performance as well as significant reduction on material requirement. An experimental analysis was conducted for a 50% truncated concentrator to validate the ray tracing analysis and the thermal performance as a function of inlet temperature of water and the surface temperature of absorber. The experimental results show good agreement with the ray-tracing program written for theoretical evaluation. Consequently, the truncation of the concentrator provides requirement of less amount of optical component through significant reductions in size of reflector and glass cover with a small reduction in concentrator rate to achieve the economic viability and attraction for buildings.

As one promising energy resource, methane hydrate (MH) has extracted worldwide attention in recent years. In 2017, a new series of methane hydrate (MH) extraction tests was executed both in China (Shenhu Area, South China Sea) and Japan (Nankai Trough), which led to new round of intense scientific research and engineering developments toward the common goal of robust production technology. This study is focused on the production behavior analysis and numerical predictions for 2017 tests in Shenhu Area, South China Sea. Based on the open production data, the detailed production process, characteristics and future prospects are re-constructed and numerically discussed, so as to provide a general view of the production behaviors and potential prediction in this region. Numerical simulations on the mid-term (60 days) production process are designed and found good agreement with the real production tests, where the short-to mid-term production rate is estimated to drop from 3.5 × 104 m3/d to around 2.0 × 103 m3/d within 60 days, which is then extended for mid-to long-term (2–3 years) prediction of gas production. Parameter behaviors and field information such as the near-wellbore effects are also discussed into detail based on the numerical results. In addition, future concerns based on recent tests in China and Japan in 2017 are also included in this study, so as to provide a general viewpoint for oceanic methane hydrate extraction.

A thin liquid film flow goes fully upward along the outer surface of a rotating cone, when the cone is immersed in the liquid, turned upside down and rotated. We derive equations for the velocities and the film thickness of the rising film flow by using the boundary layer theory, and solve them analytically and numerically. The film thickness is obtained analytically in the centrifugal zone, while it is numerically in the Coriolis zone where two different branches with a turning point are found. It is proven that the upper branch is unstable for normalized film thickness δ+&gt 3 from Rayleigh's criterion.

To use and understand the large-scale natural convection in the building and systems, heat transfer analysis of the natural convection with radiation is important. The radiation effect is influenced by concentration of the participating media in the considered system. In this study, an effects of concentration of participating media on turbulent natural convection inside a cubic cavity were investigated. The turbulence effect was modeled by large eddy simulation. Further, the radiative heat transfer was calculated by the radiation element method using the ray emission model. In addition, the gas radiation was modeled by the full-spectrum k-distribution method. By varying the partial pressures of H2O and CO2, the effect of the participating media were evaluated. From the calculation, gas radiation effects affected the flow instability and restrained the temperature stratification when the concentration of the participating media was higher. However, the convective heat transfer have not been affected by the significant flow instability by the radiation effects.

This study is focused on the utilization of oceanic methane hydrate as an energy resource under the real production situations of Nankai Trough, Japan. Due to the complex geological conditions and the sensitive thermal-mechanical properties of methane hydrate bearing layers, it is very difficult to extract and utilize the methane hydrate stably and economically. The current status of development in Japan and major challenges from real reservoir-scale analysis are discussed. Low-carbon emission process is discussed and shown into detail with careful numerical modeling procedures. The numerical model is constructed based on the geological conditions of Nankai Trough of Japan. Numerical model is also scaled-up from single thin-layer to thick multi-layer model for real reservoir conditions, based on the recent geological survey data. In the current study, the production behaviors, boundary conditions and reservoir parameter effects are discussed into detail. The predicted production rate level in this simulation agrees with recent real tests. It is found that proper selection of layer models and production strategy is very important for large-scale simulation and prediction. Combined methods and strategic production design are recommended in future real tests.

© 2018 The Japan Society of Mechanical Engineers. This study focuses on the diffusion phenomena in ethanol-water systems. The diffusion coefficient of ethanol-water systems has a strong concentration dependency originating from intermolecular interactions and the association of molecules in solution. Recently, it has been suggested that flavor variation in whiskey is partly due to different storage conditions that can affect molecular structure variation. To evaluate the molecular structure variation, diffusion coefficient measurements are considered effective. To quantitatively evaluate the variations in the diffusion process and measure the mass diffusion coefficient, the analysis method was improved to measure the concentration field more precisely. Two ethanolic solutions were prepared in this study: one preserved under normal conditions and the other was stored under isothermal conditions for 496 days. By comparing diffusion processes occurring under different storage conditions, the different diffusion coefficients were determined and the effect of storage conditions was discussed. The diffusion coefficient of the ethanolic solution stored under an isothermal condition was smaller than that of the solution stored under normal conditions.

© 2018 The Japan Society of Mechanical Engineers. The objective of this study is to visualize the flow pattern in methane hydrate (MH) reservoir model under atmospheric pressure condition. A method to mimic a real MH reservoir was introduced into the present research to visualize the multiphase flow pattern in porous media under thermal fluid injection. First, porous media mimicking real MH reservoir were prepared in a visualization cell with dual horizontal wells, which were composed of glass beads, ice of sodium bicarbonate (NaHCO3) aqueous solution and ethanol (C2H5OH). Thereafter, hydraulic fracturing by injecting C2H5OH aqueous solution was executed to generate flow path that increases permeability between the injection well and production well. The flow pattern in the reservoir model with the flow path was then visualized during the injection of hydrochloric acid (HCl) aqueous solution. The dominant factors governing the multiphase flow in fractured porous MH mimicking reservoir were evaluated. It was found that the flow path formation with high permeability by hydraulic fracturing and permeability increment by ice melting are of critical importance for the reservoir mimicking system. In addition, it is found that the liquid phase flow may also be affected by the formation of gas phase inside the porous media that mimic the dissociation process in the real MH reservoir.

© 2017 Elsevier Ltd The heat transfer process and initial stage of coupled convection at a gas–liquid interface are observed with high temporal and spatial resolutions in view of understanding phase transition dynamics such as evaporation or condensation for energy technologies. A high-speed phase-shifting interferometer is used to precisely measure the transient heat conduction and convection processes near the gas–liquid interface of a small water droplet. In the present study, the transient heat conduction around a water droplet interface during the adiabatic expansion process before the appearance of convection is visualized and examined. In the visualization experiment, transient density variations due to heat conduction in the vicinity of the gas–liquid interface are observed with temporal and spatial resolutions of 1 ms and 8.83 μm/pixel, respectively. It is determined that convection appears at approximately t = 0.25 s in a fast depressurization process, while transitions in both temperature and pressure are observed. In addition, the transient density variations and distributions of the gas phase before convection are compared with numerical simulations as an optical path length difference, and there is good agreement between the simulations and experimental results. The measurement methods developed in this study can be applied in the measurement of interfacial heat and mass transfers with high temporal and spatial resolutions.

Tumor metastasis to lymph nodes is an important contributory factor for cancer-related deaths despite recent developments in cancer therapy. In this study, we demonstrate that tumor in the proper axillary lymph node (PALN) of the mouse can be treated by the application of external laser light to trigger the unloading of doxorubicin (DOX) encapsulated in thermosensitive liposomes (TSLs) administered together with gold nanorods (GNRs). GNRs + DOX-TSLs were injected into a mouse lymph node containing cancer cells (malignant fibrous histiocytoma-like cells) and intranodal DOX release was activated using near-infrared (NIR) laser irradiation. The temperature changes arising from the laser-irradiated GNRs triggered the release of DOX from the TSLs. A greater degree of inhibition of tumor growth was found in the co-therapy group compared to the other groups. The treatment effect was achieved by a combination of chemotherapy and NIR-activated hyperthermia. In vivo bioluminescence imaging and histological analysis confirmed tumor necrosis in response to combined treatment. This work presents a theranostic approach with excellent treatment results that has the potential to be developed into an alternative to surgery for the treatment of breast cancer metastasis. [GRAPHICS] .

Methane hydrate (MH) is one well-known promising energy resources, which has been proved to exist widely around the world and in large amount. Though there are several proposals for efficient utilization system of MH, challenges still remains in the production enhancement. In this study, a new strategic production model is proposed for oceanic MH extraction and offshore power generation with Carbon Capture and Storage (CCS). The batch type design is facilitated with vertical well system and warm-up process, which is executed before and during the continuous gas extraction from MH reservoir. The system includes a methane gas extraction system, power generation system and CO2/H2O injection system. The re-injection of hot water/CO2 sustains the sensitive heat for the dissociation extraction process in a typical strategic production lifecycle. Numerical simulation shows that this design is possible to enhance the long-term gas production. Thermal balance and sensitive heat supply are proved to be of special importance for production rate. The analysis of power generation and CCS system show a general efficiency of 40% for this design. The selection of amine use, the effect of injection conditions and the feasibility of the proposed extraction/generation system are also discussed into detail in this study. (C) 2017 Elsevier Ltd. All rights reserved.

Methane hydrate has become one of the important topics in recent years as there are more and more reports on possible actual production systems. The most challenging problem for stable methane hydrate production from sea beds or under permafrost regions lies in the complex flow and transportation process, which usually occurs inside the unconsolidated porous layers. The current study is focused on laboratory-scale explorations of the basic dissociation behaviors of methane hydrate. A high-pressure experimental system for the methane hydrate synthesis and dissociation process has been established in this study. The experimental system is specially designed to form and store the methane hydrate under high pressure and low temperature conditions. The mixing of sand with the formed methane hydrate makes it possible to control the initial saturation for dissociation in the current study. A numerical simulation model for core-scale dissociation flow has also been set up, and good agreement with the experimental data was found. It is found that the dissociation on a core scale is more heat-transfer controlled. Through comparisons with previous experimental and numerical results, it is known that the operation strategy will significantly affect the dissociation parameter behaviors. The effects of the initial temperature and permeability on the dissociation process are also shown in this study. Future considerations of core-scale models and reservoir-scale production strategies are also discussed in detail. (C) 2017 Elsevier Ltd. All rights reserved.

Systemic delivery of an anti-cancer agent often leads to only a small fraction of the administered dose accumulating in target sites. Delivering anti-cancer agents through the lymphatic network can achieve more efficient drug delivery for the treatment of lymph node metastasis. We show for the first time that polymeric gold nanorods (PAuNRs) can be delivered efficiently from an accessory axillary lymph node to a tumor-containing proper axillary lymph node, enabling effective treatment of lymph node metastasis. In a mouse model of metastasis, lymphatic spread of tumor was inhibited by lymphatic-delivered PAuNRs and near-infrared laser irradiation, with the skin temperature controlled by cooling. Unlike intravenous injection, lymphatic injection delivered PAuNRs at a high concentration within a short period. The results show that lymphatic administration has the potential to deliver anti-cancer agents to metastatic lymph nodes for inhibition of tumor growth and could be developed into a new therapeutic method.

The objective of this study is to evaluate into detail on the effect of sensible heat in methane hydrate cores for gas production behavior using depressurization method under various initial temperature conditions. Firstly, methane hydrate was synthesized under low temperature and high pressure conditions in the laboratory. Methane hydrate cores were made by using methane hydrate and sand. Dissociation experiment using those cores was conducted by using depressurization method. Then, pressure, temperature, gas production rate and cumulative gas production were measured during the experiment. In the experiment, gas production rate of low porosity core with Tini of 2.5°C was higher than that of low porosity core with Tini of 1.5°C in the first 10 minutes. That implies sensible heat used for methane hydrate dissociation in the low porosity core with Tini of 2.5°C was higher than that in the other core due to initial temperature deference between these low porosity cores. Therefore, it is important to increase initial temperature of methane hydrate reservoir for enhancement of gas production rate under depressurization.

Radiative heat transfer between two semi-infinite parallel media is analyzed in the transition zone between the near-field and the classical macroscopic, i.e. incoherent far field, regimes of thermal radiation, first for model gray materials and then for real metallic (Al) and dielectric (SiC) materials. The presence of a minimum in the flux-distance curve is observed for the propagative component of the radiative heat transfer coefficient, and in some cases for the total coefficient, i.e. the sum of the propagative and evanescent components. At best this reduction can reach 15% below the far-field limit in the case of aluminum. The far-to-near-field regime taking place for the distance range between the near-field and.the classical macroscopic regime involves a coherent far-field regime. One of its limits can be practically defined by the distance at which the incoherent far-field regime breaks down. This separation distance below which the standard theory of incoherent thermal radiation cannot be applied anymore is found to be larger than the usual estimate based on Wien's law and varies as a function of temperature. The aforementioned effects are due to coherence, which is present despite the broadband spectral nature of thermal radiation, and has a stronger impact for reflective materials. (C) 2016 Elsevier Ltd. All rights reserved.

It is difficult to accurately measure the absolute value of the surface temperature of a material through ordinary methods such as with a thermocouple or a thermistor. This is due to heat loss along the electrical lead wires of the component, which causes conduction error and can ultimately influence the results. In this paper, we propose a thermistor probe that utilizes a guard heater. The goal of this design is to obtain an accurate measurement of the surface temperature of a material at a higher temperature than the ambient temperature. The probe consists of two thermistors, each with a diameter of 0.43 mm. One thermistor was utilized for the temperature sensor, while the other was used with the guard heater to minimize heat loss, and inserted into a fluorinated ethylene propylene (FEP) tube. The guard heater was placed above a half-exposed thermistor, and operated as both a sensor and a heater in order to minimize the temperature difference between the two thermistors. To evaluate the minimization of heat loss along the thermistor's lead wires in a surface temperature measurement, experiments were conducted with the surface of an aluminum block heated to 35.00 �C in two scenarios. Measurements were taken using a guard-heated thermistor probe with and without guard heating. The experimental results showed that the surface temperature was measured as 34.98 �C in the scenario where guard heating was utilized, and 34.79 �C in the scenario where it was not utilized. Therefore, the results experimentally demonstrated that the guard heater allowed the thermistor probe to provide a more accurate measurement of the surface temperature, regardless of the contact method. In addition, a two-dimensional axisymmetric heat conduction analysis was also conducted. The purpose was to quantitatively evaluate the amount of heat that passes through the lead wires of a thermistor while it is measuring the surface temperature of a heated material. The calculation results confirmed that a guard heater successfully minimized heat loss through the lead wires. The minimized heat loss was −0.016 mW, which was one-sixth of the loss measured in the scenario without guard heating.

In this paper, microchannel heat sink cooling device utilizing supersonic gas flow with isentropic expansion has been designed and analyzed. The objective is to study the feasibility of the supersonic microchannel with bumped section design for electronics cooling. Numerical simulations on the designed microchannel flows and heat transfer analysis have been conducted (in conjunction with a supersonic air flow inside a heated fin array) and compared with experimental results in this paper. The performance of the designed microchannel is also compared with traditional Laval nozzles for the feasibility analysis. Under 350 and 330 K inlet temperature conditions, the calculated Nu number is found higher than pure through channel flows. The supersonic expanding flow is successfully generated with lower heat transfer temperatures and a simpler geometric shape. The design of 100-300 mu m is found to have highest heat transfer for integrated microchannel width selection. For electronics cooling tests, the newly designed supersonic channel is found sufficient for a cooling capacity around 1.4 MW/m(2). In addition, the supersonic flow and heat transfer characteristics are also discussed into detail in this paper. [2016-0037]

The boundary layer interaction effect of the turbulent natural convection in the gap between symmetrically heated vertical parallel plates was evaluated using a numerical simulation in the present study. A large eddy simulation was conducted, and a Vreman model was used as a dynamic subgrid-scale model. The numerical simulation was validated thorough a comparison with the experimental result for the turbulent natural convection adjacent to a single vertical heated plate. The boundary interaction effect was investigated by varying the gap between the parallel plates. The results showed that the flow for vertical parallel plates had a lower heat transfer rate than a vertical plate flow. The boundary layers and vortex structure were evaluated. The heat transfer was reduced as a result of a reduced velocity gradient in the outer region of the velocity boundary layer. The averaged heat transfer was similar to that of the laminar flow. (C) 2016 Elsevier Ltd. All rights reserved.

Methane hydrate is one of the most promising future energy resources for humankind. In recent years, due to its vast existence in permafrost regions and deep ocean beds, increasing attention has been paid to the extraction, transportation and utilization of methane hydrate. The current study proposed core-scale numerical investigation models for the complex multiphase dissociation flows of methane hydrate inside porous media, which is a continuation and an extension of previous numerical investigations. The current numerical model focuses on the depressurization process and thermal boundary effects and discusses the parametric effects of the core-scale internal flows and controlling factors of the dissociation boundaries. The new findings with respect to the dissociation front movement and water-ice equilibrium effects during the dissociation process are also analyzed in this study. Ice formation and boundary heat conduction limitations are found to be critical for the smooth production of methane gas. Based on these results, trade off and production strategies for depressurization methods and thermal stimulation methods are also discussed in detail. It is hoped that this study will be useful for related core-scale analysis and possible engineering system designs. (C) 2016 Elsevier Ltd. All rights reserved.

With the fast development of electronic systems and the ever-increasing demand of thermally "smart" design in space and aeronautic engineering, the heat transfer innovations and high heat flux challenges have become a hot topic for decades. This study is aimed at the effective cooling heat transfer design by super-/sub-sonic air flow in microscale channels for high heat flux devices. The design is based on the low temperature flows with supersonic expansion in microscale, which yields a compact and simple design. By careful microelectromechanical process, microscale straight and bumped channels (with simple arc curve) are fabricated and experimentally tested in this study. The microscale flow field and density distributions under new designs are visualized quantitatively by an advanced phase-shifting interferometer system, which results are then compared carefully with numerical simulations. In this study, large differences between the two designs in density distribution and temperature changes (around 50 K) are found. The high heat flux potential for supersonic microchannel flows is realized and discussion into detail. It is confirmed that the bump design contributes significantly to the heat transfer enhancement, which shows potential for future application in novel system designs. (C) 2016 Elsevier Ltd. All rights reserved.

Non-imaging collectors are of great interest to supply thermal energy for domestic and industrial applications at temperatures of 60-300 degrees C for their configuration of non-tracking of sun and wide range acceptance angle. In particular, cylindrical CPC with tubular absorber have attractive properties such as all side illuminating absorber and eliminating the back side heat losses. Due to steep angle at the end of reflector, CPCs tolerate truncations without any significant reduction on the performance. On the other hand, non-uniform temperature distribution around the absorber may cause undesirable temperature gradient and causes hot spot presence in which very intense solar radiation occurs. It is particularly important for solar concentrator hybrid with photovoltaic system. Non-uniform distribution of the solar irradiation on the PV cell surface results in uneven current distribution that reduces the electric output. In order to reduce the presence of hot spots on the receiver area, a cylindrical CPC was evaluated for different truncation level. The optical and thermal efficiency of the concentrator were evaluated to determine the optimum truncation levels. A detail analysis was carried out for average efficiency as function of incident angle and annual performance for different absorber surfaces such as gray and selective surface. In order to decide the uniformity of the solar illumination on the absorber, the heat flux and temperature distribution on the absorber were evaluated. The truncation was the most effective on the incident angle of 20 degrees. The peak values of the heat flux distribution were selected to see clearly the intense heat flux reduction by truncation. In the case of 50% truncation, the maximum heat flux decreases by half as the average thermal efficiency decreases only by 2%. On the other hand, the annual performance of 50% truncated CPC having selective surface increases by 5% due to the improved acceptance angle. Moreover, different absorber materials including stainless steel, aluminum and copper were considered and the temperature uniformity was evaluated for the incident angles in which the most intense heat flux occurred. The stainless steel absorber showed the maximum difference on the surface temperatures of about 3.5 K. On the other hand, for the case of the concentrator having copper absorber with 50% truncated reflector, the surface temperature was almost uniform with less component cost, and with only slight reduction on the thermal performance. (C) 2016 Elsevier Ltd. All rights reserved.

A two-stage line axis solar thermal concentrator consisting of a compound parabolic and an involute reflector was designed, and its thermal and optical performance was compared with that of a dual concentrator. The configuration of the reflectors with tubular absorber yields the highest possible concentration and uniform temperature distribution on the absorber. To reduce the heat loss from the absorber, the concentrator was covered with evacuated glass tube. The dual concentrator increases ray acceptance, which is defined as the ratio of the reflector aperture area to the glass cover diameter; hence, the concentrator can utilize incident solar radiation more effectively with only a slight increase of 28% in the glass cover circumference. This suggests the use of dual concentrators in multiple concentrator units owing to their lower component cost. The performance was evaluated by using a ray-tracing model for two-dimensional (2D) geometry. The average optical efficiency of dual and single concentrators was 57% and 37%, respectively. The thermal efficiency of the dual concentrator was 21% higher than that of single one at the absorber temperature of 373 K for the gray surface absorber. On the other hand, the selective surface absorber significantly increased the performance, suggesting that the concentrator can be used in high-temperature applications such as steam generation. Annual and seasonal performances were analyzed as well. Assuming infinite length of the line-axis concentrator's absorber pipe allows ignoring the end effects; thus, a 2D approach was adopted. As a result, the dual concentrator showed better performance for all seasons; however, the solar utilization time of both concentrator types became shorter during the winter and summer solstices because of the weak insolation resulting from the orientation of the concentrators. Therefore, a slight seasonal adjustment or a modification of the geometry is required for longer utilization. (C) 2016 International Energy Initiative. Published by Elsevier Inc. All rights reserved.

Laser-induced thermal therapy (LITT) is a noninvasive medical procedure for treatment of tumors and small lesion. Skin surface overheating and thermal damage to the undesired areas of tissue are two major concerns during thermal therapy. To determine the efficacy of forced convection surface cooling, the present study demonstrates the numerical simulation for minimizing undesired thermal damage. A two-dimensional (2D) axisymmetric cylindrical model is considered with irradiation of continuous wave (cw) laser beam. Bioheat transfer equation in conjunction with radiative transfer equation (RTE) is solved using the finite volume method (FVM) and the discrete ordinate method (DOM). Effect of variation in surface cooling on tissue temperature distribution is studied.

A nontracking, nonimaging solar concentrator with a low-heat-loss configuration was proposed, and its optical and thermal performance was investigated. The reflector has a compound parabolic and involute shape so that the absorber is heated as uniformly as possible. To eliminate heat loss by conduction and convection, the mirror and absorber are enclosed in an evacuated glass tube. The concentrator presented here was simulated for the location of Sendai, Japan, and its acceptance angle was estimated as 23.44 degrees. A ray-tracing model was developed to evaluate its optical and thermal performance. The average optical efficiency was evaluated by a 2-D ray-tracing model, and a value of 72.7% was obtained. A thermal analysis of the absorber was conducted to evaluate the temperature uniformity. The results indicate that the temperature distribution of the absorber can be considered uniform. The thermal efficiency of the proposed solar concentrator was calculated as a function of the incidence angle and absorber temperature. With a concentration ratio of 2.51, the concentrator, even at an absorber temperature of 373 K, operates with an average efficiency of 47.8%, although the absorber was assumed to have a gray surface. The concentrator's thermal efficiency was compared with that of other solar collectors, and found to be higher than that of conventional solar collectors. (c) 2015 American Institute of Chemical Engineers Environ Prog, 35: 553-564, 2016

This paper deals with the CO2 near-critical convective flow inside channels of micro-scale. Under near critical conditions, the CO2 fluid is very much expandable/compressible, the density and thermal conductivity change to be near one order of magnitude lower when temperature goes near the critical point. At the same time the Prandtl number and specific heat also form high peaks. In microchannels the effect of natural convection becomes much smaller and the highly thermal expansive fluid with very small thermal diffusivity will act like a periodic thermal plume structure evolution mode. The current study, transient stability and heat transfer characteristics of near-critical microchannel flow are analyzed by solving conservative equations of Mass, Momentum and Energy together with non-Boussinesq incorporation of thermal physical properties. The numerical study is conducted under the ranges of epsilon(T) = 0.00023 - 0.06533 and epsilon(P) = 0.01626 - 0.21951 (for critical distance parameters) with boundary heat flux (from several hundreds to 50,000 W/m(2)). It is found that in microchannels vortex flow is generated by applied boundary heat flux. The thin hot boundary perturbation and thermal-mechanical process of near-critical fluids are major factors. The local span-wise and horizontal parameter changes are also analyzed for the unique near-critical fluid flow. The heat transfer characteristics, especially horizontal acceleration and expanding features are also discussed in this study. (C) 2015 Elsevier Ltd. All rights reserved.

In this paper, a guarded hot plate (GHP) apparatus utilizing a Peltier module is proposed and developed to precisely measure the thermal conductivity of insulation material. The Peltier module is used to detect a temperature difference with high sensitivity and to precisely measure heat flux. To develop the GHP apparatus, a two-dimensional axisymmetric heat conduction analysis and calibration experiments of thermistors and Peltier module were conducted. In addition, to assess the reliability of the developed apparatus, thermal conductivity measurements for a high-density glass wool and vacuum insulation panel (VIP) were conducted. Based on the results, the expanded uncertainties of the measurements were estimated. Therefore, the apparatus was found to be reliable for conducting precise thermal conductivity measurements not only for conventional insulation materials but also for a VIP. (C) 2015 Elsevier Ltd. All rights reserved.

Photothermal therapy (PTT) using near-infrared (NIR) laser light and gold nanorods (GNRs) shows promise as a novel cancer treatment modality. However, the laser intensity required to destroy tumor cells located beneath the skin is greater than the threshold intensity that causes skin damage; thus, irradiation with laser light damages the skin as well as the tumor. Here, we show that a temperature control system allows metastatic lymph nodes (LNs) to be treated by PTT using NIR laser light and GNRs, without skin damage. A mouse model of LN metastasis was developed by injection of tumor cells, and the tumor-bearing proper axillary LN was treated with NIR laser light after injection of GNRs. The skin temperature was maintained at 45 A degrees C during irradiation by using a temperature control system. Bioluminescence imaging revealed that tumor progression was less in LNs exposed to NIR laser light and GNRs than in LNs exposed to NIR laser light alone or controls (no irradiation or GNRs). Furthermore, the skin and LN capsule were macroscopically intact on day 9 after irradiation with NIR laser light, whereas tumor cells within the LN showed apoptosis. A numerical analysis demonstrated that the high-temperature zone and the LN region showing damage were localized to an area up to 3 mm in depth. The proposed novel PTT technique, using NIR laser light and GNRs with controlled surface cooling, could be applied clinically to treat metastatic LNs located within or outside the area accessible for surgical dissection.

This article deals with the spatial and the temporal evolution of tissue temperature during skin surface cooled laser induced hyperthermia. Three different skin surface cooling methodologies viz., optical window contact cooling, cryogenic spray cooling and cryogen cooled optical window contact cooling are considered. Sapphire, yttrium aluminum garnet, lithium tantalate, and magnesium oxide doped lithium niobate are the considered optical windows. The cryogens considered are liquid CO2 and R1234yE Heat transfer in the multilayer skin tissue embedded with thermally significant blood vessels pairs is modeled using the Pennes and Weinbaum-Jiji bioheat equations. Weinbaum-Jiji bioheat equation is used for the vascularized tissue. Laser transport in the tissue is modeled using the radiative transfer equation. Axial and radial (skin surface) temperature distributions for different combinations of optical windows and cryogens are analyzed. Liquid CO2 cooled yttrium aluminum garnet is found to be the best surface cooling mechanism. (C) 2015 Elsevier Ltd. All rights reserved.

This study proposes a high-speed phase-shifting interferometer with an original optical prism. This phase-shifting interferometer consists of a polarizing Mach-Zehnder interferometer, an original optical prism, a high-speed camera, and an image-processing unit for a three-step phase-shifting technique. The key aspect of the application of the phase-shifting technique to high-speed experiments is an original prism, which is designed and developed specifically for a high-speed phase-shifting technique. The arbaa prism splits an incident beam into four output beams with different information. The interferometer was applied for quantitative visualization of transient heat transfer. In order to test the optical system for measuring high-speed phenomena, the temperature during heat conduction was measured around a heated thin tungsten wire (diameter of 5 mu m) in water. The visualization area is approximately 90 mu m x 210 mu m, and the spatial resolution is 3.5 mu m at 300,000 fps of the maximum temporal resolution with a high-speed camera. The temperature fields around the heated wire were determined by converting phase-shifted data using the inverse Abel transform. Finally, the measured temperature distribution was compared with numerical calculations to validate the proposed system; a good agreement was obtained. (C) 2015 Optical Society of America

The objective of this study is to achieve accurate and quantitative visualization of the boundary layer using a novel optical system that offers a large visualization area, fewer disturbance effects, integration with a wind tunnel and high phase, spatial and temporal resolution. A novel optical configuration was proposed to realize these features. In addition, high phase and spatial resolution could be realized by introducing a phase-shifting image processing technique. Finally, a novel prism was specially designed to implement the phase-shifting technique. In this study, the proposed system was evaluated by using it to quantitatively visualize boundary layers around a circular cylinder and over a flat plate. The effect of a tripwire on the flow was visualized by an interferogram. In the experiments on flow over a flat plate, the temperature distributions in the thermal boundary layer were measured accurately, and the velocity distributions were estimated from the measured temperature distributions. The experimental data were compared with a semi-analytical solution. Good agreement was obtained, and the relative error was within 5.0% in the temperature measurement.

Global warming is one of the most serious problems faced by humans. One method to decrease the Earth's temperature is to reduce solar irradiation by dispersing nanoparticles in the atmosphere. Submicron-diameter particles or aerosols scatter solar irradiation, whereas they are transparent to long-wavelength infrared radiation emitted by the Earth. This phenomenon has received attention in the discussions of the nuclear winter, which is an uncontrolled cooling of the global temperature. The objective of the present work is to examine the first-order approximation of the feasibility of controlling the global temperature without reducing the emission of greenhouse gases. We propose the controlled dispersion of nanoparticles into the stratosphere at an altitude of 30 km. A precise analysis of the radiative properties of particles in the solar spectrum and IR regions is conducted, and radiative transfer through the stratosphere-dispersed nanoparticles is approximated using a one-dimensional single-scattering model. Several types of nanoparticles are considered. The optimum size of the nanoparticles determined using the model is 350-450 nm. The dispersion of nanoparticles with a total mass of 3x107 tons into the stratosphere will reduce 3% of the solar irradiation. The blockage can be maintained by launching 10-ton projectiles 19 times per day from 100 launch sites.

An experimental investigation to evaluate the radiative properties of a selectively transparent thin coating on a substrate of a different material has been performed in order to evaluate its thermal behavior for applications where a low temperature at the surface exposed to the sun is desired. Copper (II) oxide (CuO) micro-particles have been used to create a pigmented coating on a paper substrate. The particle volume fraction and size have been optimized by the theoretical methodology. The spectral reflectance was measured using spectroscopy in the visible (VIS) and near-infrared (NIR) regions. The spectral emissivity was evaluated from the reflectance in IR region. The temperatures of the designed coatings and typical black paints are measured in a solar simulator. The temperature measurement was simulated by numerical analysis. The temperature of CuO coating on standard white paper was 10 degrees C lower than the ones of typical black paint while keeping the desired dark tone. (C) 2014 Elsevier Ltd. All rights reserved.

A theoretical nongray rigorous model was constructed to study the radiative heat transfer through different greenhouse covering materials by using Radiation Element Method by Ray Emission Model (REM2). This model was applied to find the difference in thermal performances performed by greenhouses that were covered with different claddings such as silica glass, Polyvinylchloride (PVC) and Low Density Polyethylene (LDPE) materials. By utilizing the wide-range spectral radiative properties (0.22-25 mu m) for these materials and taking into account the absorption and emission within the covering material, precise estimations of greenhouse temperatures have been achieved. Moreover, differences in greenhouse (enclosures) temperatures have been confirmed between the semi-transparent plastic films and opaque glass. In addition, outdoor experiments were conducted to measure how much heat can be trapped inside the three identical rectangular enclosures covered by the above mentioned materials. Enclosure inside air, ground surface and cover temperatures' measurement showed a good agreement with the calculated ones by using the rigorous model. (C) 2014 Elsevier Ltd. All rights reserved.

沖ノ鳥島の漁場開発のため本提案では永久塩泉を用いた，湧昇パイプによる海洋深層水汲み上げ手法を検討している．海洋でパイプを係留する時，海流によるパイプの傾きを考慮しなければならない．本研究では沖ノ鳥島周辺海域での湧昇パイプ係留に向け，コンテナ投下法を用いた流線形湧昇パイプ展開方法を提案し，流線形湧昇パイプの展開条件の設計とコンテナ投下法を用いたパイプ展開方法の有用性評価を行った．流線形湧昇パイプの展開条件を設計するため，水槽での抗力試験で測定した流線形湧昇パイプの抗力係数を使用し海流によるパイプ挙動のモデル化を行い，流線形パイプに必要なブイの浮力の算出を行った．またコンテナ投下法の有用性評価を行うため長さ25mの流線形湧昇パイプの展開実験を行い，パイプ展開の観察とコンテナ落下運動の解析を行った．

Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering. (C) 2013 Elsevier Ltd. All rights reserved.

Lymph node dissection for regional nodal metastasis is a primary option, but is invasive and associated with adverse effects. The development of non-invasive therapeutic methods in preclinical experiments using mice has been restricted by the small lymph node size and the limited techniques available for non-invasive monitoring of lymph node metastasis. Here, we show that photothermal therapy (PTT) using gold nanorods (GNRs) and near-infrared (NIR) laser light shows potential as a non-invasive treatment for tumors in the proper axillary lymph nodes (proper-ALNs) of MXH10/Mo-lpr/lpr mice, which develop systemic swelling of lymph nodes (up to 13 mm in diameter, similar in size to human lymph nodes). Tumor cells were inoculated into the proper-ALNs to develop a model of metastatic lesions, and any anti-tumor effects of therapy were assessed. We found that GNRs accumulated in the tumor in the proper-ALNs 24 h after tail vein injection, and that irradiation with NIR laser light elevated tumor temperature. Furthermore, combining local or systemic delivery of GNRs with NIR irradiation suppressed tumor growth more than irradiation alone. We propose that PTT with GNRs and NIR laser light can serve as a new therapeutic method for lymph node metastasis, as an alternative to lymph node dissection. (C) 2013 Elsevier B.V. All rights reserved.

An inverse method was conducted to obtain the spectral optical properties of four greenhouse covering materials, (Low Density Polyethylene (LDPE), Polyolefin (PO), Polyvinylchloride (PVC) and Fused Silica Glass). Diffuse reflectance and transmittance of the covering materials were measured using spectrophotometric method; the complex index of refraction in the range between 0.22 and 25 mu m was deduced by inverse calculation using Radiative Element Method by Ray Emission Model (REM2). At longwave radiation, the optical constants of opaque glass material were found by utilizing Kramers-Kronig method resulting good correlation with results obtained by other investigations. A rigorous model for radiative heat transfer analysis to an agricultural greenhouse was developed. The greenhouse covering material was analyzed as a non-gray one-dimension plane-parallel medium subjected to solar and thermal irradiation using REM2. Specular reflectance and diffuse incident irradiation were treated at the boundary surfaces and absorption and emission were taken into account. Thermal performance was evaluated for the above mentioned covering materials. (c) 2013 Elsevier Ltd. All rights reserved.

Supercritical CO2 fluid has been widely used in chemical extraction, chemical synthesis, micro-manufacturing and heat transfer apparatus, and so forth. The current study deals with near-critical CO2 microchannel mixing flow and its basic characteristics. Careful numerical investigations are carried out by solving the coupled computational fluid dynamic equations. The results show that strong near-critical vortex flows can be achieved in a relatively wide range of initial and controlling conditions in microchannels. Basic, isothermally developed flows are simulated and then used as the initial state for a heat convective simulation. After the wall heat flux is applied, the vortex mixing flow originates from the hot boundaries in microchannels with height D=100μm to 200μm, while natural convection will gradually become dominant for microchannels with D=300μm to 500μm. The current micro-mixing evolution can be ascribed to a novel type of Kelvin-Helmholtz instability. Well-correlated characteristic numbers are identified for the effective near-critical microchannel mixing cases. The vortex growth and evolution mode in microchannels are found to differ greatly from previous micro-mixing methods. Possible applications in micro-engineering/chemical process are also discussed in this study. © 2013 Elsevier Ltd.

We present two-dimensional numerical investigations of the temperature and velocity evolution of a pure near-critical fluid confined in microchannels. The fluid is subjected to two sides heating after it reached isothermal steady state. We focus on the abnormal behaviors of the near-critical fluid in response to the sudden imposed heat flux. New thermal-mechanical effects dominated by fluid instability originating from the boundary and local equilibrium process are reported. Near the microchannel boundaries, the instability grows very quickly and an unexpected vortex formation mode is identified when near-critical thermal-mechanical effect is interacting with the microchannel shear flow. The mechanism of the new kind of Kelvin-Helmholtz instability induced by boundary expansion and density stratification processes is also discussed in detail. This mechanism may bring about innovations in the field of microengineering. © 2013 American Physical Society.

This paper describes an inverse method for estimating the local thermal diffusivity of biomaterials such as meats and vegetables using a thermophysical handy tester. A thermophysical handy tester is a fast, non-invasive, in-situ, local device for measuring the thermophysical properties of a material. However, it cannot be applied to soft or liquid materials precisely. In this study, an inverse analysis of this device was conducted to make it applicable to the measurement of the thermophysical properties of these materials. In the proposed inverse analysis, a real coded genetic algorithm (GA) was used to minimize the objective function. First, a calibration experiment of the device was conducted by using water to determine the apparatus constant. Then, this inverse method was validated by measuring the thermal diffusivity of some materials such as agar-gelled water, silicone oil, and glycerol. It was found that, the estimated thermal diffusivity shows good agreement with the reference value. Moreover, the thermal diffusivity of various biomaterials such as vegetables and meats was estimated, and reasonable values could be obtained by a proposed method. © 2013 by JSME.

The diffusion process of deep seawater drawn up by a vertical pipe deployed in the ocean is investigated. This vertical pipe is based on the principal of perpetual salt fountain. Numerical simulations of seawater upwelling from the pipe are performed based on experiments conducted in the Mariana trench region. Two turbulence modeling approaches were examined: k-ε model and Large Eddy Simulations (LES). The results in both models show that diffusion of the deep seawater diffusion after ejection from the pipe. The LES results show a 50% lower vertical penetration compared to the k-ε model as well as well as predicting that the horizontal diffusion is stronger than the vertical one.

A quasi common path phase-shifting interferometer for convection measurement was developed in this paper. This interferometer has a large measurement area of approximately 100 mm in diameter to visualize the spatial structure of natural convection. It also has a quasi common path to reduce the effects of air disturbance and vibration. In addition, a phase-shifting technique is introduced to improve the interferometer's phase resolution and spatial resolution. Natural convection fields around a vertical flat plate with Rayleigh numbers from 1.9 × 10 6 to 3.0 × 10 6 were measured and the temperature profiles were estimated by the interferometer. The obtained temperature profiles were compared with the analytical solutions. Moreover, the three-dimensional effect of a thermal boundary layer was investigated. To validate the interferometer's capability, the experimental results were compared with the calculated results in terms of changes in the optical path length of the test beam. It was confirmed that the quasi common path phase-shifting interferometer can measure the optical path length change accurately at high phase and spatial resolutions. © 2012 Elsevier Ltd. All rights reserved.

A quasi common path phase-shifting interferometer for convection measurement was developed in this paper. This interferometer has a large measurement area of approximately 100 mm in diameter to visualize the spatial structure of natural convection. It also has a quasi common path to reduce the effects of air disturbance and vibration. In addition, a phase-shifting technique is introduced to improve the interferometer's phase resolution and spatial resolution. Natural convection fields around a vertical flat plate with Rayleigh numbers from 1.9 × 10 6 to 3.0 × 10 6 were measured and the temperature profiles were estimated by the interferometer. The obtained temperature profiles were compared with the analytical solutions. Moreover, the three-dimensional effect of a thermal boundary layer was investigated. To validate the interferometer's capability, the experimental results were compared with the calculated results in terms of changes in the optical path length of the test beam. It was confirmed that the quasi common path phase-shifting interferometer can measure the optical path length change accurately at high phase and spatial resolutions. © 2012 Elsevier Ltd. All rights reserved.

A power generation system with low carbon dioxide (CO2) emission is proposed. This system simultaneously performs power generation, methane hydrate utilization, and carbon dioxide capture and storage (CCS). In this system, CO2 resulting from the combustion is recovered by compressed seawater. A thermal stimulation method was selected to dissociate the oceanic methane hydrate. CO2-dissolved seawater is heated by the exhausted gas and injected into the hydrate layer to dissociate the methane hydrate. By means of process simulation, a feasibility study of the proposed system was conducted, during which a power generation system with approximately 30% thermal efficiency and above 90% CO2 recovery rate was achieved. Moreover, to quantify the heat loss during the injection of hot seawater into the hydrate layer, we conducted a numerical simulation of the internal pipe flow and determined that the appropriate pipe diameter can be selected in terms of heat and pressure loss through the pipe. In addition, the outlet temperature can be predicted by the thermal conductivity and the thickness of the insulation material. An appropriate insulation material can be selected to obtain the desired outlet temperature. (C)2012 Elsevier Ltd. All rights reserved.

In this study, a phase-shifting interferometer to conduct real-time high-resolution measurements of concentration profiles in binary diffusion fields was developed. The phase-shifting interferometer comprises a Mach-Zehnder interferometer, a rotating polarizer, a CCD camera, and an image-processing unit. A phase-shifting technique was used to determine the phase difference between a test beam and a reference beam by using three images taken at intervals of 1/30 s. The phase difference is obtained for a spatial resolution of 640 x 240. This data is further processed in real-time to visualize the concentration profile inside a diffusion cell. The diffusion coefficient is determined by performing an inverse analysis of the experimental concentration profile. The objective function makes use of a numerical calculation, based on Fick's law, for which the initial experimental concentration profile is taken as initial condition. The diffusion field was formed inside a thermally controlled diffusion cell with optical paths as large as 20 mm. This large optical path allows measurements of diffusion fields with concentration differences as narrow as 1 mg/ml. In order to validate the measurement method, the concentration dependence of the isothermal diffusion coefficient of NaCl and Sucrose was determined in the dilute region at 25 degrees C, such values being extensively reported in the literature. It was found that our optical system is much faster and accurate than similar optical systems to determine the diffusion coefficients in binary systems. (C) 2012 Elsevier Ltd. All rights reserved.

本報では，点接触式熱物性測定法を軟質材料及び液体へ適用する場合の課題を提起し，この課題に対してポリイミド薄膜を用いた新しい測定手法を提案した．また，ポリイミド薄膜が測定に与える影響を検証するために数値計算を行い，その影響を明らかにした．さらに，水や寒天などの熱伝導率測定を行った結果，再現性は改善されたものの，ポリイミド薄膜の影響によって算出される見かけの熱伝導率と文献値に差異が生じた．しかしながら，各試料の測定結果の間に相関があることから修正式を考慮することで，正確な熱伝導率を算出できる可能性を示した．

Moxibustion therapy has been used in East Asian medicine for more than a thousand years. However, there are some problems associated with this therapy in clinical practice. These problems include lack of control over the treatment temperature, emission of smoke, and uneven temperature distribution over the treatment region. In order to resolve these problems, we developed a precise temperature-control device for use as an alternate for conventional moxibustion therapy. In this paper, we describe the treatment of a single patient with paralytic ileus that was treated with moxibustion. We also describe an evaluation of temperature distribution on the skin surface after moxibustion therapy, the development of a heat-transfer control device (HTCD), an evaluation of the HTCD, and the clinical effects of treatment using the HTCD. The HTCD we developed can heat the skin of the treatment region uniformly, and its effect may be equivalent to conventional moxibustion, without the emission of smoke and smell. This device can be used to treat ileus, abdominal pain, and coldness of abdomen in place of conventional moxibustion in modern hospitals.

This paper reports the measurement of the binary mass diffusion coefficient for proteins with a wide range of molecular size. The diffusion coefficient is obtained by conducting diffusion experiments in the dilute region. Transient concentration profiles were measured by a phase-shifting interferometer and subsequently compared with a numerical calculation based on Fick's law to determine the diffusion coefficient. Distilled water was used as solvent in free diffusion experiments conducted at T = (25 +/- 1.0)degrees C. The method was validated by measuring the diffusion coefficient of aqueous NaCl, Sucrose, and BSA, which values have been extensively reported in the literature. The values of the diffusion coefficient for seven proteins: aprotinin (6.5 kDa), alpha-lactalbumin (14.2 kDa), lysozyme (14.3 kDa), trypsin inhibitor (20.1 kDa), ovalbumin (44.2 kDa), bovine serum albumin (66.7 kDa), and phosphorylase b (97.2 kDa), were determined in the dilute region of 0-3 mg/ml. The results are compared with the Stokes-Einstein equation. The influence of the molecular structure and pH on the diffusion coefficient is discussed.

This study describes nanoparticle pigmented coatings used in controlling the radiative properties of surfaces exposed to sunlight. The effect of particle dispersed state to reflectance of the coating is discussed. As the dispersed particles, TiO2 and Fe2O3 are used. From Raman spectral intensity measurements made on the coating, the dispersed state of particles was investigated. The spectral reflectance of the coating was measured by spectroscopy. The reflectivity of the coating is analyzed theoretically. In this calculation, the dispersed state is assumed to be monodispersed and homogeneous. Comparison between experimental and numerical results shows that the difference between the measured and calculated reflectance increases as the volume fraction increases. The maximum absolute error of reflectance is about 10% when the volume fraction is 0.05. In contrast, the maximum absolute error of reflectance is about 3% when the volume fraction is 0.01. The control of dispersed state affects the radiative properties of pigmented coatings.

This study describes nanoparticle pigmented coatings used in controlling the radiative properties of surfaces exposed to sunlight. The effect of particle dispersed state to reflectance of the coating is discussed. As the dispersed particles, TiO2 and Fe2O3 are used. From Raman spectral intensity measurements made on the coating, the dispersed state of particles was investigated. The spectral reflectance of the coating was measured by spectroscopy. The reflectivity of the coating is analyzed theoretically. In this calculation, the dispersed state is assumed to be monodispersed and homogeneous. Comparison between experimental and numerical results shows that the difference between the measured and calculated reflectance increases as the volume fraction increases. The maximum absolute error of reflectance is about 10% when the volume fraction is 0.05. In contrast, the maximum absolute error of reflectance is about 3% when the volume fraction is 0.01. The control of dispersed state affects the radiative properties of pigmented coatings.

Moxibustion, one of the thermal therapies used in oriental medicine, has several problems, including the fact that temperature distribution over a treatment region is not uniform, the treatment temperature cannot be controlled, and smoke is emitted. To solve these problems, we developed a precise thermal heat transfer control device and applied it to clinical medicine as a substitute for conventional moxibustion. The abdominal heating controller developed in this study has an effect equal to that of moxibustion and can heat the treatment region of human skin uniformly. The treatment effect of the device was evaluated in a clinical experiment, in which we found that these devices can treat ileus, diarrhea, and related disorders. We sought the optimal temperature for thermal therapy with regard to gender, body mass index, and age. We carried out a numerical simulation of temperature distribution inside a human body when the abdominal region is heated. Temperature distribution of the heated abdominal region was calculated using a 2-D axisymmetric model considering bioheat generation such as blood perfusion and metabolism. The calculation results confirmed that the thermal effect cannot reach the viscera. © 2011 Wiley Periodicals, Inc.

In this paper the concentration dependency of mass diffusion coefficients in binary system was investigated. We have developed a novel and accurate visualization system using a small area of transient diffusion fields by adopting a phase shifting technique. Through accurate visualization of the transient diffusion field, it is possible to determine the mass diffusion coefficient. Unlike a conventional interferometer, the proposed system provides high spatial resolution profiles of concent-ration even though the target area is less than 1.0 mm. This allows the measurement of local transient diffusion field with a high accuracy. The determination of mass diffusion coefficient of each component in multi-component system was also conducted. For the accurate and reliable measurement of mass diffusion coefficient, the experimental error should be taken into account. The experimental data usually contains unexpected accidental error and inherent errors of the measurement system. In this study, an optimization technique using conjugate gradient method is developed for the precise determination of the mass diffusion coefficients. The difference between the experimental and numerical concentration distribution is set as the objective function for the optimization method. The conjugate gradient method searches the optimal value by minimizing the objective function. For the concentration dependency evaluation, sodium chloride (NaCl) in pure water was selected as solute. For determination of each mass diffusion coefficient in multi-component system, NaCl and lysozyme in buffer solution was selected. The experiments were performed under isothermal conditions. The proposed measurement method was validated by comparing the measured data with those available in the literature. The results indicated that the concentration dependency was successfully investigated from the experimental data. The mass diffusion coefficient of each component also could be determined from the experimental data as evidenced by good agreement with the published data. The difference between the reference and determined value of mass diffusion coefficient was less than 10%. It can be said that the diffusion of each solute inside the cell progresses independently within the dilute concentration ranges and the superposition principle of concentration of NaCl and lysozyme was satisfied. The influence of concentration of solution on the diffusion process and allowable concentration range of the superposition principle are determined and discussed. © 2010 by ASME.

This paper describes a novel cooling system to be applied in cryosurgery. An ultrafine cryoprobe has been developed to treat small lesions which cannot be treated by conventional cryoprobes. The main problem of the ultrafine cryoprobe is the reduction of the heat transfer rate by the small flow rate due to the large pressure drop in a microchannel and the large ratio of the surface area to the volume. In order to overcome these problems, we utilized boiling heat transfer in a microchannel as the heat transfer mechanism in the ultrafine cryoprobe. The objectives of this paper are to develop an ultrafine cryoprobe and evaluate its cooling characteristics. The ultrafine cryoprobe has a co-axial double tube structure which consists of inner and outer stainless steel tubes. The outer and inner diameters of the outer tube are 0.55mm and 0.3mm, respectively. The outer and inner diameters of the inner tube are 0.15mm and 0.07mm, respectively. The inner tube serves as a capillary tube to change the refrigerant from liquid state to two-phase flow. Furthermore, two-phase flow passes through the annular passage between the inner and out tube. The hydraulic diameter of the annular passage is 0.15mm. Furthermore, HFC-23 (Boiling point is -82.1°C at 1atm) is used as the refrigerants. The temperature of the ultrafine cryoprobe was measured. The lowest temperatures were -45°C in the insulated condition and -35°C in the agar at 37°C (which simulates in vivo condition). Furthermore, the frozen region which is generated around the ultrafine cryoprobe was measured 5mm from the tip of cryoprobe at 120s, and resulted to be 3mm in diameter. Moreover, the change of the refrigerant state is calculated by using the energy conservation equation and the empirical correlations of two-phase pressure drop and boiling heat transfer. As a result, the refrigerant state in the ultrafine cryoprobe depends on the external heat flux. Finally, the required geometry of the ultrafine cryoprobe to make high cooling performance is evaluated. © 2010 by ASME.

We have developed a novel cryoprobe for skin cryosurgery utilizing the Peltier effect. The four most important parameters for necrotizing tissue efficiently are the cooling rate, end temperature, hold time and thawing rate. In cryosurgery for small skin diseases such as flecks or early carcinoma, it is also important to control the thickness of the frozen region precisely to prevent necrotizing healthy tissue. To satisfy these exacting conditions, we have developed a novel cryoprobe to which a Peltier module was attached. The cryoprobe makes it possible to control heat transfer to skin surface precisely using a proportional-integral-derivative (PID) controller, and because it uses the Peltier effect, the cryoprobe does not need to move during the operation. We also developed a numerical simulation method that allows us to predict the frozen region and the temperature profile during cryosurgery. We tested the performance of our Peltier cryoprobe by cooling agar, and the results show that the cryoprobe has sufficient cooling performance for cryosurgery, because it can apply a cooling rate of more than 250 degrees C/min until the temperature reaches -40 degrees C. We also used a numerical simulation to reconstruct the supercooling phenomenon and examine the immediate progress of the frozen region with ice nucleation. The calculated frozen region was compared with the experimentally measured frozen region observed by an interferometer, and the calculation results showed good agreement. The results of numerical simulation confirmed that the frozen region could be predicted accurately with a margin of error as small as 150 mu m during use of the cryoprobe in cryosurgery. The numerical simulation also showed that the cryoprobe can control freezing to a depth as shallow as 300 mu m. (C) 2009 Elsevier Inc. All rights reserved.

近年，レーザー治療は患者への負担が比較的小さく，美容整形や温熱療法の分野において極めて重要な役割を果たしている．しかしながら，レーザーの強度や照射範囲によっては正常な部位にまで火傷などの障害を引き起こす可能性も少なくない．そこで，より精度の高いレーザー治療を行うためには，生体内における光伝播と熱伝導を考慮したシミュレーション法の開発が重要である．本研究では，生体組織の生体光拡散現象について解き，さらに生体熱伝導方程式と連成させることによって，レーザー治療時における生体内の温度分布を推定することを目的とする．

The objective of this study is to develop a new simulator for laser therapy. In order to minimize undesired effects on the laser therapy, it is important to precisely predict for heat and photon transport inside a biological tissue. In the present study, the photon transport is solved with the Radiation Element Method by Ray Emission Model (REM2), and then coupled with bioheat transfer equation. The dimensionless results become valuable guidance for developing a laser therapy system.

A living body has a system for maintaining its temperature. We have investigated the heat transfer characteristics common to each organ and therapy using heat transfer. The one-dimensional bioheat transfer equation with bioheat generation was converted into a dimensionless form and solved by Laplace transformation on the assumption that biological tissue is homogeneous. A dimensionless steady-state solution and transient solution were derived analytically. These solutions can represent the characteristics of the temperature distribution common to each organ. Comparison with numerical solutions has confirmed that these solutions can be applied to estimate the temperature distribution of inhomogeneous biological tissue. It is proved that the size of the region where temperature change occurs, the steady-state thermal penetration depth, is decided by biological properties. Furthermore, the time needed to reach a steady state, or the time it takes for biological tissue to reach a steady state, is calculated by using these solutions. Additionally, a temperature chart was proposed for each organ or tissue. This chart can serve as a guideline for medical doctors in formulating thermal therapy. © 2008 Wiley Periodicals, Inc.