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The incidence of endometrial cancer is increasing worldwide. One of the main causes of this cancer is a hormone imbalance; progesterone derivatives have been used for treatment. However, reports have shown that hypoxia plays important and possibly beneficial roles in endometrial function. Here, we show the effect of hypoxia on the proliferation of human endometrial adenocarcinoma Ishikawa cells. Hypoxia induced caspase-dependent apoptosis in Ishikawa cells. Overexpression and siRNA-mediated knockdown of hypoxia-inducible factor-1α (HIF-1α) confirmed that HIF-1α accelerates hypoxia-induced cell death. Treatment with dimethyloxalglycine, which stabilizes HIF-1α, suppressed cell proliferation. Kaplan-Meier analysis showed that the expression level of HIF-1α has a significant positive effect on the survival rate of endometrial cancer patients. In our search for cellular targets involved in hypoxic apoptosis, we noticed that mammalian sterile 20-like kinase 2 (MST2), a member of the Hippo pathway, was positively correlated with HIF-1α expression in 176 endometrial cancer patients extracted from the TCGA database. Hypoxia induced caspase-dependent MST2 cleavage. In addition, a MST2 inhibitor suppressed HIF-1α-mediated reporter activity. These results suggest HIF-1α and the Hippo signaling pathway are involved in endometrial cancer.

In recent years, thermophoresis has emerged as a promising tool for quantifying biomolecular interactions. The underlying microscopic physical effect is still not understood, but often attributed to changes in the hydration layer once the binding occurs. To gain deeper insight, we investigate whether non-equilibrium coefficients can be related to equilibrium properties. Therefore, we compare thermophoretic data measured by thermal diffusion forced Rayleigh scattering (TDFRS) (which is a non-equilibrium process) with thermodynamic data obtained by isothermal titration calorimetry (ITC) (which is an equilibrium process). As a reference system, we studied the chelation reaction between ethylenediaminetetraacetic acid (EDTA) and calcium chloride (CaCl2) to relate the thermophoretic behavior quantified by the Soret coefficient ST to the Gibb’s free energy ΔG determined in the ITC experiment using an expression proposed by Eastman. Finally, we have studied the binding of the protein Bovine Carbonic Anhydrase I (BCA I) to two different benzenesulfonamide derivatives: 4-fluorobenzenesulfonamide (4FBS) and pentafluorobenzenesulfonamide (PFBS). For all three systems, we find that the Gibb’s free energies calculated from ST agree with ΔG from the ITC experiment. In addition, we also investigate the influence of fluorescent labeling, which allows measurements in a thermophoretic microfluidic cell. Re-examination of the fluorescently labeled system using ITC showed a strong influence of the dye on the binding behavior.

Anisotropic wicking surfaces have attracted the attention of numerous research groups in recent years. Wicking characteristics can be improved by generating unidirectional flow behavior within surfaces composed of micropillars that are bent in the direction of interest. In the present work, we created surfaces composed of bent polymerized pillar arrays with center-to-center spacings of 250 and 500 µm and experimentally investigated boiling heat transfer under subcooled flow conditions (40 K). The test surfaces were chemically coated with a 200-nm-thick hydrophilic layer to evaluate the effects thereof on subcooled flow boiling. Surface anisotropy and the center-to center spacings between neighboring pillars significantly improved surface wickability and boiling heat transfer, compared to surfaces with vertically polymerized pillars. Enhancements of the critical heat flux (17–34%) and the heat transfer coefficient (8–71%) were evident on polymerized pillar surfaces compared to bare polymerized surfaces. The experimental results were validated by theoretically analyzing the relationship between the liquid pinning forces and the polymerized pillar surfaces' configurations to understand better how boiling heat transfer was enhanced on anisotropic wicking surfaces during subcooled flow boiling.

Optical confusion refers to a camouflage technique assimilated with the surroundings through manipulating colors and patterns. With the advances in multispectral imagery detection systems, multispectral camouflage studies on simultaneous deceptions in the visible to infrared ranges remain a key challenge. Thus, creating pixelated patterns is essential for mimicking background signatures by assimilating both colors and patterns. In this study, a multispectral optical confusion system (MOCS) comprising pixelated silicon-based fractal nanostructures (Si-FNSs) is introduced to realize multispectral optical confusion. We analyzed the fractality of the Si-FNSs to understand the relationships between structural characteristics and optical properties with the aggregation phenomenon. The aggregation phenomenon changes the morphological heterogeneity by up to 38.5%, enabling a controllable range of visible reflectivity from 0.01 to 0.12 and infrared emissivity from 0.33 to 0.90. Visible and infrared colors were obtained by controlling the wet-etching time from 10 to 240 min and temperature from 40 to 100 °C. Finally, the MOCS consisting of pixelated Si-FNSs was designed and created by extracting the pattern from the simultaneously captured visible and infrared background images. Using the artificial backgrounds representing these images, we evaluated and compared the multispectral optical confusion performance of the MOCS with conventional camouflage surfaces.

In daily life, many people use large amounts of personal care products (PCPs) on a regular basis. For determining the risk to consumers, product usage amount, frequency of use, and co-use patterns are essential information. In this study, the PCP usage patterns of Korean consumers were analyzed, and the data were used to develop a probabilistic risk assessment. A web-based questionnaire was used to evaluate the PCP usage patterns of consumers. A model developed by Crème Global in conjunction with the Research Institute for Fragrance Materials was used to measure the systemic exposure to PCP ingredients. The use rates of 10 PCP family are compared with reported values obtained for populations in California and Switzerland which showed some distinct characteristics of Korean consumers. The co-use combinations of the 10 families of products frequently used by consumers were analyzed in an attempt to calculate aggregate exposure. Seven ingredients were selected and the aggregate risk assessment were performed based on bootstrapping analysis. The probability of the Hazard Quotient of all seven ingredients exceeding 1 was zero. The data of the usage patterns of Korean consumers reported here will be of value in developing more precise aggregate exposure risk analysis.

Abstract This study introduces a thermophoretic lab-on-a-chip device to measure the Soret coefficient. We use resistive heating of a microwire on the chip to induce a temperature gradient, which is measured by fluorescence lifetime imaging microscopy (FLIM). To verify the functionality of the device, we used dyed polystyrene particles with a diameter of 25 nm. A confocal microscope is utilized to monitor the concentration profile of colloidal particles in the temperature field. Based on the measured temperature and concentration differences, we calculate the corresponding Soret coefficient. The same particles have been recently investigated with thermal diffusion forced Rayleigh scattering (TDFRS) and we find that the obtained Soret coefficients agree with literature results. This chip offers a simple way to study the thermophoretic behavior of biological systems in multicomponent buffer solutions quantitatively, which are difficult to study with optical methods solely relying on the refractive index contrast. Graphic abstract

Camouflage refers to a creature's behavior to protect itself from predators by assimilating its signature with the environment. In particular, thermal camouflage materials in the infrared (IR) wave are attracting interest for energy, military, and space applications. To date, several types of camouflage materials such as photonic crystals and metal-dielectric-metal structures have been developed. However, flexible camouflage materials still face challenging issues because of the material's brittleness and anomalous dispersion. Herein, we propose flexible thermocamouflage materials (FTCM) for IR camouflage on an arbitrary surface without mechanical failure. Without using a polymer as a dielectric layer, we realized FTCM by changing the unit cell structure discretely. By imaging methods, we verified their flexibility, machinability, and IR camouflage performance. We also measured and calculated the spectral emissivity of FTCM; they showed electromagnetic behavior similar to a conventional emitter. We quantified the IR camouflage performance of FTCM that the emissivity in the undetected band (5-8 μm) is 0.27 and the emissivity values in detected bands are 0.12 (3-5 μm) and 0.16 (8-14 μm) in the detected bands, respectively. Finally, we confirmed the IR camouflage performance on an arbitrary surface in a supersonic flowfield. FTCM are expected to help to improve our basic understanding of metamaterials and find widespread application as IR camouflage materials.

Thermodiffusion or thermophoresis gained much interest in bio, chemical, and energy engineering. Al- though there are several methods to measure thermophoresis, they consume large sample volumes, are limited to binary mixtures, and give only indirect access to the applied temperature profile. Herein, we propose a thermophoretic microfluidic cell for quantitative measurements of the Soret coefficient of col- loids. The actual microscale measuring channel lies between cooling and heating channels to achieve a one-dimensional temperature gradient. Fluorescence lifetime imaging microscopy with Rhodamine B is utilized to measure the spatial temperature profile in the channel. The fluorescence intensity of fluo- rescently labeled polystyrene particles with a diameter of 25 nm is used to monitor the concentration profile. The observed temperature and concentration profiles are one-dimensional, as gradients in the longitudinal and height directions can be neglected. In the investigated temperature range, the averaged difference between the measured Soret coefficients with the cell and determined with the Thermal Dif- fusion Forced Rayleigh Scattering set-up is less than 8%.

Recent issues in boiling heat transfer include enhancing not only heat transfer performance but also heat transfer uniformity and stability of the surface for using it as a practical cooling application. In this study, we demonstrate that ultrasonic actuation can be used to enhance the boiling heat transfer and thermal stability while also improving the temporal and spatial temperature uniformity through the acoustic field and acoustic streaming effect. The acoustic field is shown to enhance the instability between the bubble and heater interface, resulting in an increased dissipation rate of smaller bubbles and an increased, stable heat dissipation capacity. Through the particle image velocimetry (PIV), we observe the formation of convective flow and an enhancement of bubble mobility near the surface. It makes that, when ultrasonic actuation is used in the partial nucleate boiling region, the heat transfer coefficient is increased by 17%, and the temporal and spatial temperature variations are reduced to less than 70% and 65%, respectively, compared to that of the reference data. This study will help to enhance the understanding of boiling heat transfer under ultrasonic actuation.

Camouflage is a method evading predators in nature by assimilating into the environment. To realize an artificial camouflage surface for displays and sensors, many researchers have introduced several concepts including a metamaterial-selective absorber/emitter (MSAE). When an MSAE is adopted for camouflage at infrared (IR) wave, the energy dissipation of reduced emitting energy, as well as the reduction of emitting energy to deceive the IR signature from the surface, must be considered from the viewpoint of energy balance due to thermal instability. The integrated investigation of radiative heat-transfer characteristics and IR signature control of MSAE remains, however, poorly understood. Here, we investigate MSAE for IR camouflage by considering the energy balance in terms of reduction of emitting energy and dissipation of reduced emitting energy. On the basis of the atmospheric transmittance at an IR band, we designate the detected band as having wavelengths of 3-5 and 8-14 μm and the undetected band as having a wavelength of 5-8 μm. We investigate, via experiments and simulations, the optical characteristics required for IR camouflage and extract the factor that controls the emissive power. Furthermore, we suggest an integrated factor for evaluating the camouflage performance based on the concept of energy balance and propose a design guideline for MSAE with the aim of maximizing the camouflage performance at the IR band. This study will help to expand the range of applications (such as energy harvester and sensors) and others that are based on selective absorption/emission.

The development of nuclear fusion, which is an environmentally friendly and future-oriented power generation method, needs to be developed for the prevention of global warming caused by the excessive use of fossil fuels. However, there are many scientific and technical challenges that should be overcome for the use of nuclear fusion reactors. The development of a divertor is one such challenge, in that it should be able to endure a high heat flux (∼10 MW/m2) and a particle flux (∼1024/s). To solve this challenge, the Karlsruhe Institute Technology (KIT) has been developing a helium-cooled divertor with a multi-array impingement jet. The main objective of developing this divertor module is not only to sufficiently dissipate the high thermal load from plasma for a reliable operation, but also to maintain a moderate pressure drop. To achieve this objective, we should understand the heat transfer characteristics of the divertor module and enhance the thermal performance, namely, the thermal conductance and pressure drop. The present study is aimed at an enhancement of the cooling performance of a helium-cooled divertor through the addition of rib structures in the divertor module. The results show that the convective conductance with rib turbulators is increased through an increase in the interfacial area on a heated surface. In addition, the thermal performance of the divertor module is enhanced by 20% or more compared with a no rib case.

The power exhaust from high temperature plasma at the level of divertor is one of the biggest technological challenges in the path to establish fusion power reactors. At the Karlsruhe Institute of Technology (KIT), a novel helium-cooled divertor using jet impingement cooling array has been investigated as one of the possible solutions for a DEMO tokamak. The concept, consisting of tungsten armour slabs fixed on a tungsten-laminate tube inside which a jet distribution cartridge is placed, has undergone an extensive optimization process. Among other things, the heat transfer coefficient (HTC) and pressure drop over a divertor unit have been thoroughly looked upon in order to improve the divertor thermohydraulic performance. The present paper is presenting such an optimization study in which the effect on the divertor performances of the distance between the cartridge and the heat loaded surface is investigated. Given the geometrical constraints, the nozzle-to-target surface distance is changed either by increasing the diameter of the inlet manifold, or, by varying the cartridge position, starting from a coaxial configuration, to various positions closer to the impingement surface.

This paper investigates the surface heat transfer caused by interaction of a jet and a supersonic crossflow near the jet injection hole. A sonic jet with different momentum ratios ( J = 0.510 , 1.018, 1.477) was injected perpendicularly into a crossflow with a Mach number of 3.0 in a supersonic wind tunnel. Surface temperature through time measured by infrared thermography was used to deduce surface heat flux. In addition, heat transfer coefficients and adiabatic wall temperatures were derived from time histories of surface heat flux and temperature. In order to consider an effect of conduction from the inner hole surface, a three-dimensional energy conservation is considered in the deduction process of the heat flux. As a result, the characteristics of the heat transfer near the hole and the change in the heat transfer with momentum ratios are presented. The separation vortex and recirculation vortex are found to be dominant flow features in terms of the augmentation of the heat transfer. The maximum heat transfer is observed at the immediate vicinity of the hole due to the flow oscillation from a jet-mixing layer. This oscillation resulted in a 390% of augmentation of the heat transfer near the hole compared to the freestream even at the lowest momentum ratio. Also, the augmentation near the hole is more susceptible to change of momentum ratio compared to the augmentation on the overall interaction area.

In boiling heat transfer, the emerging issues are the improvement of both the critical heat flux (CHF) and the thermal stability. Nanowire-forested (NF) surfaces and subcooled environments are favorable for improving CHF as well as the thermal stability owing to their distinctive morphology and consequential convection expedition, respectively. In this study, the improvement of CHF and temperature uniformity/stability are evaluated on NF surfaces immersed in de-ionized water with subcooling from 0 to 30 K using a resistance temperature detector (RTD) sensor with five measuring points. NF surfaces catalyze dispersed, confined and fast bubble ebullitions under subcooling conditions, resulting in the delayed bubble coalescences. This lead to the enhancement of CHF accompanying stabilized spatial/temporal temperature variations. We demonstrate that NF surfaces applying 30 K subcooled condition not only significantly improve the thermal stability by reducing spatial/temporal temperature variations to less than 1/5 but also enhance CHF by 4.3 folds, compared to the plain surfaces under the saturated condition. These remarkable enhancements show that NF surfaces can be effective solutions to secure the thermal stability under vigorous boiling conditions.

In two-phase heat transfer, promising issues include not only improving the boiling performance but also the surface temperature uniformity and stability, which indicate that how long the system maintains thermal stability without a failure on the surface. In this study, the merits of micro-nano hybrid surfaces (MNHS) are discussed for enhancing the thermal uniformity/stability and boiling heat transfer performance. Spatial/temporal heat transfer characteristics are evaluated on MNHS using a local temperature-measuring sensor of resistance temperature detector (RTD). We demonstrate that MNHS can enhance not only boiling performance but also thermal uniformity/stability by delaying bubble coalescence with an appropriate design of the location of the nucleation sites and the nucleated bubble size. The confining effects of nucleated bubbles on nanowire (NW) structures and of uniform bubble nucleation on uniformly distributed micro-cavity (MC) structures lead to the reliable enhancement of thermal uniformity/stability as well as critical heat flux (CHF) in pool boiling environments. These combined effects of the NW and MC structures could delay the bubble coalescence phenomenon by catalyzing bubble nucleation dispersedly and quickly at small bubble sizes. When the normalized pitch of the nucleation sites is 1, namely the pitch of the nucleation sites and the bubble departure size have the same dimension, CHF is significantly enhanced, by more than 170%, on an MNHS versus a plain surface by delaying bubble coalescence and maximizing bubble density. Boiling heat transfer using an MNHS represents a breakthrough reducing the spatial and temporal temperature variation at CHF to less than 1/3 and 1/4, respectively, compared with a plain surface.

Nuclear fusion is the promising energy sources because the fuels for power generation are abundant and by-products are eco-friendly rather than other power generations. However, there are several conundrums that must be solved for developing the nuclear fusion plants, including DEMO (DEMOnstration nuclear fusion reactors), such as superconducting system, blanket, cryostats and others. In particular, a divertor is one of essential components because of withstanding the excessive heat flux (∼10 MW/m2) from the high-temperature plasma. Therefore, it is necessary for thermal design of divertor module under tremendous heat flux to develop the nuclear fusion plants. We investigate thermophysical behavior by convective heat transfer and suggest principle operating variables to decide for appropriate thermal design for divertor module. Based on the simplified thermal circuit, we demonstrate that the observed correlation can predict thermophysical characteristics of the divertor module and present the prerequisites for reliable thermal design based on the thermal design maps in terms of principle operating variables of divertor module. Finally, we reveal that the safety factor of thimble is primary concern to establish thermal design of divertor module. The present study will contribute to the development of divertor in nuclear fusion plants and the applications for high heat flux and temperature devices.

Nuclear fusion energy is a solution to the substitution of fossil fuels and the global energy deficit. However, among the several problems encountered for realizing a nuclear fusion reactor, the divertor presents difficulties due to the tremendous heat flux (~10 MW/m2) from high-temperature plasma. Also, neutrons produce additional heat (~17.5 MW/m3) from collisions with the materials&rsquo, atoms. This may lead to unexpected effects such as thermal failure. Thus, a comprehensive investigation on the divertor module is needed to determine the heat-absorbing capacity of the divertor module so to maintain the effect of incident heat flux. In this study, using an analytical approach and a simulation, the quantitative effect of heat generation on the thermophysical behavior, such as temperature and thermal stress, was analyzed while maintaining the incident heat flux. Then, a correlated equation was derived from the thermal design criteria, namely, the maximum thimble temperature and the safety factor at the vulnerable point. Finally, on the basis of the thermal design criteria, the heat-absorbing capacity of a nuclear fusion reactor in operating conditions was determined. This study contributes to the understanding of the divertor&rsquo, s effects in nuclear fusion reactors for high-heat-flux and high-temperature applications.

This study experimentally investigated the influence of heterogeneous wettability-patterned surfaces with varying inter-spacing on flow boiling heat transfer characteristics. The test surfaces consisted of three fluorooctyltrichlorosilane hydrophobic-patterned array structures having a triangle, inverted triangle, and circular shape on a SiO2- hydrophilic substrate, with an inter-spacing of 0.75 or 1 mm. The working fluid was deionized water, and the Reynolds number was 6,000 at atmospheric pressure. Among the test surfaces, varying the inter-spacing between neighboring hydrophobic patterns slightly enhanced the heat transfer coefficient (HTC) due to changing the bubble characteristics. In terms of the shape effect of hydrophobic patterns, the heterogeneous wettability-patterned surfaces dominated the overall flow boiling heat transfer performance showing a significant increase in critical heat flux (CHF) compared to the Si surface, by 40–43%. In addition, all of the wettability test surfaces showed a markedly higher heat transfer coefficient than the Si surface, by 35–163%. This experiment is explained by analyzing the relationship between bubble lift forces and the various hydrophobic-patterned shapes in a horizontal flow channel, in an attempt to better understand flow boiling heat transfer and optimize the pattern design.

A dual circulating fluidized bed reactor has been studied for carbon dioxide (CO2) capture. It is important to maintain the reaction temperature of the adsorbent in the carbonation–regeneration cycle. The dual circulating fluidized bed reactor will be used ultimately in the large reactors of industrial-sized power plants to control CO2 emissions. However, to date, studies have considered only small-scale reactor models, due to the limitations associated with two-phase flow dynamics and changes in the heat transfer characteristics with reactor size. In this study, we investigated the thermal design of a feasible pilot-scale reactor through thermal-fluid analysis of the reactor and heat transfer in two-phase flow. Based on our thermal-fluid experimental results for a laboratory-scale dual circulating fluidized bed reactor with an amine-functionalized silica sorbent 0.37EB-PEI, a thermal design process was carried out to increase the reactor scale. In consideration of the heat of reaction and the sensible heat for a continuous process, the increase in total heat duty at the reactor scale has been determined. In the overall heat transfer process of the reactor, consisting of three heat transfer mechanisms, the bed-to-wall heat transfer by gas-solid fluidization was identified as the dominant mechanism. The scale-up of the fluidized bed resulted in a change in gas-solid behaviors and a lower heat transfer coefficient. Ultimately, through the thermal design process, the heat exchange area required for a large-scale carbonation reactor and regeneration reactor were derived; specifically, for the pilot-scale reactor to accommodate > 2000 m3/h flue gas, the required reactor height was estimated to be about two times compared to not taking the scale-up effect into account. We proposed a multi-tube reactor with the high heat transfer coefficient and the large heat transfer area for an efficient large-scale CO2 capture system.

Emerging issues in boiling heat transfer include enhancing heat transfer uniformity/stability, and critical heat flux (CHF). Microcavity structures improve heat transfer uniformity/stability by departing bubbles with arranged formation due to pinning effects and regular pitch. Ultrasonic actuation induces an acoustic field on departed bubbles, and this enhances contact line instability between the bubble and microcavity structures, resulting in an increased dissipation rate of smaller bubbles. In this study, we demonstrate that synergetic effects from microcavity structures and ultrasonic actuation can enhance CHF and thermal stability while also improving temporal/spatial temperature uniformity. Applying microcavity structures with ultrasonic actuation, we observe smaller and faster bubbles' departure with the proposed formation. These bubble departure characteristics on the microcavity surface with ultrasonic actuation enhance CHF and thermal stability by delaying bubble coalescence and ensuring liquid paths between smaller and faster-departed bubbles. Thus, when ultrasonic actuation is applied to the microcavity structure, CHF increased by 20%, and temporal/spatial temperature variations near CHF were reduced to less than 1/2 and 1/3, respectively, compared to no actuation case. This research will help to understand the interaction of ultrasonic wave and bubbles, and to show the way to overcome CHF limitations of passive methods using microsized structures.

Selective laser melting (SLM) is a promising additive manufacturing technique arising from glassy metal characteristics of treated medium. When creating novel compositions of materials and intricate workpieces, reliable thermal designs should be implemented based on well-understood heat transfer characteristics on matierlas to be used. Herein, we investigate local and overall heat transfer characteristics of SLM processes and investigate the principal parameters related to the magnituge of a radiative heating power and its exposure time. We present how to exert their influence upon local melting and sequential solidification of copper powder bed. The local solid media reach a quasi-equilibrium state in even 1 ms with the incident powers of 50, 100, and 200 W. The anisotropic expansion of the molten pool is governed by a thermally-induced Marangoni flow. As the power is increased, the Marangoni factor increases linearly up to 853.7%. Consequential heat transfer characteristics tell us that unconditional input power should be avoided to prohibit the detrimental effect; the radiative heating power should be confined for thermalization of a target domain and for that preventing the evaporation of a material. These approaches from material science to heat transfer can be used to develop a platform for SLM processes guaranteeing its feasibility and applicability.

The objective of this study is to design a broadband and wide-angle emitter based on metamaterials with a cut-off wavelength of 2.1 µm to improve the spectral efficiency of thermophotovoltaic emitters. To obtain broadband emission, we conducted the geometric parameter optimization of the number of stacked layers, the inner and outer radii of the nano-rings, and the thickness of the nano-rings. The numerical simulation results showed that the proposed emitter had an average emissivity of 0.97 within the targeted wavelength, which ranged from 0.2 µm to 2.1 µm. In addition, the presented multilayer nano-ring emitter obtained 79.6% spectral efficiency with an InGaAs band gap of 0.6 eV at 1400 K.

In this study, we investigate the interfacial droplet jetting characteristics and thermal stability of a focused surface acoustic wave device (F-SAW). An F-SAW device capable of generating a 20 MHz surface acoustic wave by applying sufficient radio frequency power (2&ndash, 19 W) on a 128&deg, rotated YX-cut piezoelectric lithium niobate substrate for interfacial droplet jetting is proposed. The interfacial droplet jetting characteristics were visualized by a shadowgraph method using a high-speed camera, and a heat transfer experiment was conducted using K-type thermocouples. The interfacial droplet jetting characteristics (jet angle and height) were analyzed for two different cases by applying a single interdigital transducer and two opposite interdigital transducers. Surface temperature variations were analyzed with radio frequency input power increases to evaluate the thermal stability of the F-SAW device in air and water environments. We demonstrate that the maximum temperature increase of the F-SAW device in the water was 1/20 of that in the air, owing to the very high convective heat transfer coefficient of the water, resulting in prevention of the performance degradation of the focused acoustic wave device.

Effect of the cross-sectional geometry on heat transfer and particle motion of circulating fluidized bed riser for CO2 capture was investigated. Numerical simulation using Eulerian-eulerian method with kinetic theory of granular flow was adopted to analyze gas-solid flow consisting in circulating fluidized bed riser. Circular, square, and rectangular cross-sectional geometry cases of the same area were carried out. Rectangular cross-sectional geometries were analyzed having aspect ratios of 1: 2, 1: 4, 1: 8, and 1:16. The cross-sectional geometry significantly influenced the particle motion and heat transfer. The downward flow pattern of solid particles near the wall was changed. The gas-solid mixing degree of the riser with the rectangular cross section of the high aspect ratio was the lowest. There were differences in bed-to-wall heat transfer coefficient according to rectangular geometry with different aspect ratios., {"references":["N. MacDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson, C.S. Adjiman, C.K. Williams, N. Shah, P. Fennell, \"An overview of CO2 capture technologies\", Energy & Environmental Science. vol., 3, 2010, pp. 1645.","C.-H. Yu, A \"Review of CO2 Capture by Absorption and Adsorption\", Aerosol and Air Quality Research, 2012.","H.T. Bi, N. Ellis, I.A. Abba, J.R. Grace, \"A state-of-the-art review of gas–solid turbulent fluidization\", Chemical Engineering Science., vol. 55, 2000, pp. 4789–4825.","H. Moon, H. Yoo, H. Seo, Y.-K. Park, H.H. Cho, \"Thermal design of heat-exchangeable reactors using a dry-sorbent CO2 capture multi-step process\", Energy, vol. 84, 2015, pp. 704–713.","H. Yoo, H. Moon, H. Seo, Y.K. Park, H.H. Cho, \"Effect of a diffuser on gas-solid behavior in CFB riser for CO2 capture\", Journal of Mechanical Science and Technology, vol. 30, 2016, pp. 3661–3666.","S. Choi, H. Yoo, H. Moon, Y.-K. Park, H.H. Cho, \"Heat transfer and gas-solid behaviors in pneumatic transport reactor used of carbon capture system\", Journal of Mechanical Science and Technology, vol. 31, 2017, pp. 5081–5087.","H. Yoo, H. Moon, S. Choi, Y.-K. Park, H.H. Cho, \"Effect of the jet direction of gas nozzle on the residence time distribution of solids in circulating fluidized bed risers\", Journal of the Taiwan Institute of Chemical Engineers, vol. 71, 2017, pp. 235–243.","S.W. Kim, S.D. Kim, \"Effects of particle properties on solids recycle in loop-seal of a circulating fluidized bed\", Powder Technology, vol. 124, 2002, pp. 76–84.","M.J. Rhodes, S. Zhou, T. Hirama, H. Cheng, \"Effects of operating conditions on longitudinal solids mixing in a circulating fluidized bed riser\", AIChE Journal, vol. 37, 1991, pp. 1450–1458.\n[10]\tH. Moon, S. Choi, Y.-K. Park, H.H. Cho, \"Thermal-fluid characteristics on near wall of gas-solid fluidized bed reactor\", International Journal of Heat and Mass Transfer, vol. 114, 2017, pp. 852–865.\n[11]\tY K Mohanty, G K Roy, K C Biswal, \"Effect of column diameter onf dynamics of gas-solid fluized bed: A stastical approach\", Indian Journal of Chemical Technology, vol. 16, 2009, pp. 17–24.\n[12]\tU. Arena, A. Marzocchella, L. Massimilla, A. Malandrino, \"Hydrodynamics of circulating fluidized beds with risers of different shape and size\", Powder Technology, vol. 70, 1992, pp. 237–247.\n[13]\tL.G. Gibilaro, R. Di Felice, S.P. Waldram, P.U. Foscolo, \"Generalized friction factor and drag coefficient correlations for fluid-particle interactions\", Chemical Engineering Science, vol. 40, 1985, pp. 1817–1823\n[14]\tD.J. Gunn, \"Transfer of heat or mass to particles in fixed and fluidised beds\", International Journal of Heat and Mass Transfer, vol. 21, 1978, pp. 467–476.\n[15]\tD. Geldart, \"Types of gas fluidization, Powder Technology\", vol. 7, 1973, pp. 285–292.\n[16]\tD. Gidaspow, R. Bezburuah, and J. Ding, \"Hydrodynamics of Circulating Fluidized Beds, Kinetic Theory Approach\", In Fluidization VII, Proceedings of the 7th Engineering Foundation Conference on Fluidization. 1992, pp. 75–82.\n[17]\tC. K. K. Lun, S. B. Savage, D. J. Jeffrey, and N. Chepurniy, \"Kinetic Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flow Field\", J. Fluid Mech, vol. 140, 1984, pp. 223–256."]}

Enhancing the critical heat flux (CHF), which is the capacity of heat dissipation, is important to secure high stability in two-phase cooling systems. Coolant supply to a dry hot spot is a major mechanism to prevent surface burn-out for enhancing the CHF. Here, we demonstrate a more ready supply of coolant using aligned silicon nanowires (A-SiNWs), with a high aspect ratio (10) compared to that of conventional random silicon nanowires (R-SiNWs), which have a disordered arrangement, for additional CHF improvement. We propose the volumetric wicking rate, which represents the coolant supply properties by considering both the liquid supply velocity and the amount of coolant (i.e., wicking coefficient and wetted volume, respectively). Through experimental approaches, we confirm that the CHF is enhanced as the volumetric wicking rate is increased. In good agreement with the fabrication hypothesis, A-SiNWs demonstrate higher coolant supply abilities than those of R-SiNWs. The longest (7 μm) A-SiNWs have the highest volumetric wicking rate (25.11 × 10

Interface-inspired convection is a key heat transfer scheme for hot spot cooling and thermal energy transfer. An unavoidable trade-off of the convective heat transfer is pressure loss caused by fluidic resistance on an interface. To overcome this limitation, we uncover that nano-inspired interfaces can trigger a peculiar fluidic interactivity, which can pursue all the two sides of the coin: heat transfer and fluidic friction. We demonstrate the validity of a quasi-fin effect of Si-based nanostructures based on conductive capability of heat dissipation valid under the interactivity with fluidic viscous sublayer. The exclusive fluid-interface friction is achieved when the height of the nanostructures is much less than the thickness of the viscous sublayers in the turbulent regime. The strategic nanostructures show an enhancement of heat transfer coefficients in the wall jet region by more than 21% without any significant macroscale pressure loss under single-phase impinging jet. Nanostructures guaranteeing fluid access via an equivalent vacancy larger than the diffusive path length of viscid flow lead to local heat transfer enhancement of more than 13% at a stagnation point. Functional nanostructures will give shape to possible breakthroughs in heat transfer and its optimization can be pursued for engineered systems.

The general pharmacological properties of 2-amino-9-(3-acetoxymethyl-4-isopropoxycar-bonyloxybut-1-yl) purine (CAS 247081-81-8, SK 1899), a new potential antiviral agent, were investigated in mice, rats, guinea pigs, rabbits, and dogs. The oral administration of 50, 150, and 500 mg/kg of SK 1899 had no effects on the central nervous system except that it slightly increased the spontaneous locomotor activity in mice at a dose of 500 mg/kg. SK 1899 did not disturb either the spontaneous motility or contractor-induced contraction of the isolated organs such as guinea pig ileum, rat uterus, guinea pig vas deferens, and guinea pig trachea at concentrations up to 10 –4 mol/l. It slightly increased the contractile force in the isolated guinea pig atrium at a concentration of 10 –4 mol/1. Following intravenous infusion of 5, 15, and 50 mg/kg of SK 1899 to anesthetized dogs, it did not change the mean arterial pressure, heart rate, left ventricular systolic pressure (LVSP), and respiratory rate, while it slightly increased the left ventricular positive dP/dt max (LV + dP/dt max ) at a dose of 50 mg/kg. SK 1899 did not induce any significant changes in the intestinal charcoal meal transit in mice, basal gastric juice secretion in rats, and renal function in rats. It did not affect the blood coagulation system and phenolsulfonphthalein secretion in rats. These findings suggest that SK 1899 has a very low potential to induce any adverse pharmacological effects at the doses showing antiviral activity.

The solution reaction of btp [2,6-bis(N1-1,2,4-triazolyl)pyridine] with copper acetate afforded a secondary building unit (SBU) precursor of [Cu2(OAc)4(btp)2] · 2MeOH (1) which yielded the [Cu2(OMe)2]2+ SBU by the reaction of 1 with CuX2 salts (X = [BF4]−, [ClO4]− and [OTf]−) in methanol and acetonitrile mixture. According to solid-state structural analysis, self-assembly of SBUs is dependent on the size of the anion. In the case of [BF4]− and [ClO4]−, SBUs are self-assembled to be 3D cages of [[[Cu4(μ-OMe)4(μ-btp)4(BF4)2(MeCN)2] ⊃ (BF4)](BF4)][[[Cu4(μ-OMe)4(μ-btp)4(BF4)(MeOH)(MeCN)2] ⊃ (BF4)](BF4)2] (2) and [[Cu4(μ-OMe)4(μ-btp)4(ClO4)2(MeCN)2] ⊃ (ClO4)](ClO4) · 2H2O (3) by the anion-templating effect, where two SBUs are bridged by four btp ligands. The bending of Cu2O planes along the O⋯O hinge causes the btp ligands to get close enough to interconnect two [Cu2(OMe)2]2+ SBUs in addition to the orthogonal arrangement of Cu⋯Cu axes of each SBU. Meanwhile, the large anion [OTf]− was not capable of the 3D cage but a 1D infinite coordination polymer of [[Cu2(μ-OMe)2(μ-OTf)2(btp)2](H2O)]n (4) in which SBUs are doubly bridged by btp ligands in a zigzag pattern.

2,2-Dimethyl-3,4-dialkoxy-substituted 6-aminobenzopyran analogues (eg., 7 and 8) were identified as prolyl 4-hydroxylase inhibitors via a screening process using HSC-T6 and LI 90 cells that express an immortalized rat hepatic stellate cell line and as part of a test of the type I collagen contents employing the ELISA method. A subsequent lead optimization effort based on solid-phase parallel synthesis led to the identification of 2,2-dimethyl-3,4-dialkoxy-substituted 6-aminobenzopyrans as potent inhibitors of prolyl 4-hydroxylase.