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Luminescence thermal quenching (TQ) is one of the most critical problems to be solved for further improvement of phosphors' applications in lighting and many other fields. Herein, a novel strategy is demonstrated to achieve outstanding anti‐TQ performance with a substantial enhancement of Eu3+ red emission at 613 nm from Sc2MO3O12:Tb3+,Eu3+ phosphor. Its anti‐TQ performance is endowed by dual energy transfer (ET) pathways and intensified by the negative thermal expansion (NTE) property of the Sc2MO3O12 host. Remarkably, the photoluminescence (PL) emission intensity of Eu3+ from Sc2MO3O12:20%Eu3+,2%Tb3+ phosphor at 648 K reaches 507.3% of the initial intensity taken at 298 K. The lifetime of Eu3+ emission at 613 nm elongates with increasing measurement temperature. The experimental data and density functional theory (DFT) calculations reveal that the host structure shrinkage via NTE leads to the thermally boosted Eu3+ red emission by intensifying the consecutive ET and confinement of the absorption light. The potential of this phosphor as a dual‐mode high temperature thermometer based on both emission lifetime and intensity ratio read‐out modes is realized. This work provides inspiration to combine multiple strategies to achieve broad and dramatic anti‐TQ phosphors with enhanced performance for various optical applications. [ABSTRACT FROM AUTHOR]

A unified numerical model for simulating thermal flows past and through porous media whose thermal properties are identical with those of the surrounding fluid is proposed in this paper, which advances the work of the unified immersed boundary‐lattice Boltzmann flux solver (UIB‐LBFS). The proposed method greatly simplifies the conventional computation procedure for thermal flows past porous bodies by unifying the governing equations for the flow and temperature fields in both the porous and fluid domains. This is achieved by introducing a diffuse layer, across which the variation of the flow properties including its thermal features are expected to be smooth. Also, the developed method can be applied on either uniform or nonuniform grid since the numerical fluxes are locally reconstructed by LBFS at cell interfaces. In addition, the boundary conditions for both the flow and temperature fields at the porous‐fluid interface with complex shape can be implemented through IBM in a simple way. The proposed method is validated by several numerical examples over wide ranges of thermal parameters from forced convection to mixed convection. Excellent agreements are obtained for all simulations, including the one with severe temperature gradient in the thin temperature boundary layer at Pr=10$$ \mathit{\Pr}=10 $$, which demonstrates the capabilities of the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the flow and thermal properties of a combined multiple shell pass (CMSP)‐shell and tube heat exchanger (STHE) with the provision of unilateral ladder‐type helical baffle (ULHB) and continuous helical baffle (HB) in the outer shell pass of the heat exchanger. Two CMSP‐STHEs with ULHB and HB, respectively, are compared with the traditional STHE having segmental baffles (SG‐STHE) using the computational fluid dynamics method. The computational outcomes are validated with the empirical correlations of the Kern and Esso method. The Reynolds‐averaged Navier–Stokes‐based standard k–ω turbulence model accurately predicts the heat transfer (HT) rate and pressure drop. The computed results of HT rate, pressure drop, and logarithmic mean temperature difference corresponding to various mass flow rates (m) for three STHEs are presented. The results show that the overall HT rate of CMSP (ULHB)‐STHE and the CMSP (HB)‐STHE at the same mass flow rate are nearly 28.3% and 14.8% larger than that of traditional SG‐STHE, respectively. Furthermore, the overall area‐weighted average pressure drop (ΔP) of CMSP (HB)‐STHE is smaller than that of SG‐STHE by 26.5% at the same mass flow rate (m) and for CMSP (ULHB)‐STHE it is larger by 2% than that of traditional STHE. Based on the above results, it is concluded that the CMSP (ULHB)‐STHE is a suitable replacement for the conventional SG‐STHEs. [ABSTRACT FROM AUTHOR]

The cross‐flow heat exchanger involves a tractor moving between two fluids that flow in a direction perpendicular to each other, and one of the fluids is often a liquid and the other is a gas. This type of heat exchanger has been studied in many previous studies for its importance in air conditioning applications and many industrial applications. In this type of heat exchanger, the surface area for heat transfer is very large. Therefore, many techniques have been used to improve the thermal and dynamic performance of this type of heat exchanger. In this study, previous studies that used metallic foam as one of the ways to improve the performance of heat exchangers were reviewed. The most important techniques that were used in previous studies during the process of evaluating the thermal performance of a cross‐flow heat exchanger in the presence of different types of metal foam were clarified. The use of metal foam depends on important factors, including (1) the type of material, where copper and aluminum were used in most of the previous studies, due to their availability and ease of foam formation using these materials, in addition to the good thermal properties, (2) porosity, where the porosity value of metal foam ranged between 0.85 and 0.98 in the previous studies, (3) the density of pores, most of the studies ranged between 10 and 40 PPI. [ABSTRACT FROM AUTHOR]

Permafrost regions are experiencing increasing air temperatures, accelerating the thawing process, and thickening the active layer in summer. This can accelerate the release of greenhouse gasses into the atmosphere from the organic carbon stored in the permafrost. The long‐term thawing rates of permafrost below the active layer are governed by the soil thermal properties, the heat capacity, and thermal conductivity, which vary due to differences in grain sizes and distribution and organic matter content. Using nine column experiments comprised of fully saturated synthetic permafrost samples exposed to freeze–thaw cycles, the relative contributions of a range of soil grain sizes and organic matter contents on the soil thermal properties were investigated. The columns were subjected to a freeze and thaw cycle while soil temperatures were recorded in profiles. To infer the thermal properties from these experimental data, a numerical heat transfer model was used. The best fit between the observations and a batch of 5544 numerical models was used to find optimum values for permafrost thermal properties. The optimized heat capacity varied between 500 and 650 (J/m3 K) and thermal conductivity between 2.45 and 3.55 (W/m K). These optimized parameters were subsequently used to model a 100‐year permafrost active layer thaw scenario under warming air temperatures. Variations in the optimized thermal properties resulted in a time difference in thawing depth of 10–15 years and thawing depths varied between 9 and 10 m between the different optimized thermal properties at the end of the 100‐year scenario. Core Ideas: A numerical 1D heat transport model was used to simulate freeze–thaw transitions of permafrost column experiments.The numerical heat transfer model accurately simulated laboratory freeze–thaw dynamics.Numerically obtained thermal conductivity, heat capacity and porosity correspond well with field observations.Variations in organic matter content affect both thaw depth and thaw timescales. [ABSTRACT FROM AUTHOR]

One of the commonly used stabilization systems for rock tunnel is shotcrete. However, the hydration of shotcrete is usually accompanied by the development of internal defects and micro damage under high temperature. Additionally, in the actual high‐temperature engineering, the temperature of the rock tunnel exhibits irregular changes. Therefore, in this study, the curing conditions of constant temperature (23°C, 40°C, 60°C, 80°C) and variable temperature (23–40–60–80°C, 80–60–40–23°C) are set, respectively. The mechanical properties and structural properties of polyurethane shotcrete and ordinary Portland shotcrete are introduced. It is determined that the limit temperature for inhibiting the development of sprayed concrete's compressive and splitting strength is between 60°C and 80°C, and the limit temperature for inhibiting the development of bond strength is about 40°C. Meanwhile, the influence of high temperature on the thermal insulation performance of shotcrete is considered. The results that the self‐foaming performance of polymer(polyurethane) reduces the thermal conductivity of shotcrete. Based on this phenomenon, the heat transfer model of shotcrete at room and high temperature is established to clarify the heat transfer process of shotcrete. Results will provide theoretical basis for further research of durability and heat insulation performance of protective spraying material for tunnel under high temperature. [ABSTRACT FROM AUTHOR]

The combined study of electroosmosis, peristalsis, and heat transfer with multiple slips like velocity slip, thermal slip, and concentration slip, is applicable in designing biomimetic thermal pumping systems at the microscale of interest in physiological transport phenomena, such as drug delivery systems. A mathematical model is developed to study the non‐Newtonian (third‐grade) fluid flow driven by the applicable forces to generate the pressure gradient under the effects of rheological properties. The analysis is performed in an electro‐magnetohydrodynamic environment to examine the Lorentz force effect. The microchannel walls are propagating and subjected to natural peristaltic pumping. The Poisson and the Nernst–Planck equations are utilized to model electroosmotic phenomena. The Debye–Hückel approximation is considered to acquire Boltzmann circulation of electric potential across the electric double layer. The low‐Reynolds‐number and long‐wavelength approximations are employed to simplify the governing equations. Simplified coupled nonlinear governing equations are simulated by the ND Solver of Mathematica software and validated with existing results. The impact of emerging physical parameters on flow, heat transfer, and pumping characteristics are discussed. Additionally, a fundamental peristaltic pumping phenomenon known as trapping is graphically provided and briefly discussed. [ABSTRACT FROM AUTHOR]

Graded materials (GM) possess superior thermo‐mechanical properties, which are not feasible to obtain with homogeneous materials (HM), and hence in this paper, the transient response of a longitudinal fin of varying geometry made up of GM is reported. The temperature‐dependent convection coefficient and heat generation parameters are considered to account for real‐world high‐temperature applications of fins. Fin material properties such as density and specific heat remain constant while thermal conductivity is assumed to vary axially based on four different physically possible variations namely, linear, quadratic, power, and exponential variations. The typical nonlinear differential equation obtained for fins was solved by using a mesoscopic scale‐based particle tracking method called the Lattice Boltzmann method. The Lattice Boltzmann solver has been implemented in form of an in‐house MATLAB code and validated with existing results, thereafter it is developed for solving the foregoing problems. The results obtained are reported for rectangular, triangular, convex, and concave profiles under step change in base temperature and base heat flux. The performance of graded fins is investigated in terms of time required to attain steady‐state and fin tip temperature which are inherent design parameters in the case of the transient fin. Inhomogeneity index and profile function have a significant effect on the performance of fin in terms of resistance to heat flow. Hereby, in comparison with HM fins, GM fins have lower resistance to heat flow irrespective of fin profiles. Concurrently, comparative analysis for fins of different profiles made of HM and GM is also done to facilitate the designer in selecting the most appropriate fins. [ABSTRACT FROM AUTHOR]

In this work, effects of sealing temperature, time, pressure, as well as sealant thickness and viscosity on squeeze out flow (SOF) in heat sealing were examined. A new image analysis approach is presented to quantify SOF in heat sealing. It was found that increasing temperature or pressure could improve SOF but only in thick 130 μm sealants and reducing the sealant thickness to 50 μm suppressed SOF. Reducing viscosity in 50 μm sealant films was also found to improve SOF only at high‐sealing pressure and long sealing times. Three approaches were used to model SOF: analytical one‐dimensional model, numerical one‐dimensional model using finite difference method (FDM), (iii) Numerical two‐dimensional model using finite element analysis. Heat transfer was modeled, and it was shown that heat transfer induces a delay in SOF. When the FDM and the heat transfer models were combined, a good agreement between experimental and model prediction could be obtained. In addition, modeling results showed that SOF occurred in shear rates within the transition region between the Newtonian and Power‐law regions. This indicates the importance of considering the Carreau‐Yasuda fluid behavior in modeling of SOF. [ABSTRACT FROM AUTHOR]

A common calculation error of thermal processes in injection molding simulation programs is caused by the inadequate description of the heat transfer between the polymer melt and the wall of the mold. No correct description of the effect of pressure on the heat transfer coefficient is available for the numerical calculations of injection molding yet. During the injection molding cycle, the pressure of the melt can vary from atmospheric pressure to thousands of bars. When such a high pressure is applied, the heat transfer coefficient can change several orders of magnitude. To calculate heat removal accurately, we developed a novel measuring method and based on the measurement data, we created a model that describes the heat transfer coefficient as a function of pressure and temperature. Calculated maximal heat transfer coefficients vary between 250 and 800 W/(mK) at the pressure of 500 bar. The pressure dependence of the heat transfer coefficient can be described with a sigmoid function. The heat transfer coefficient increases as the temperature difference between mold and melt increases and as pressure increases. We determined measurement error and found it to be less than 5%. [ABSTRACT FROM AUTHOR]

In this work, composite samples were fabricated through melt blending with mesocarbon microbeads (MCMBs) and polyamide‐66 (PA66). Noteworthily, the thermal conductivity (TC) of the composites reached 1.51 W/m K with 60 wt% MCMBs, and the mechanical properties and heat resistance of PA66/MCMB composite were significantly improved. It was mainly due to the formation of heat transfer network at high filler content and their good dispersion in the matrix. The present work provided a new selection of thermally conductive fillers and expanded the application of MCMB in thermal management materials. [ABSTRACT FROM AUTHOR]

In this study, thermal insulation and solar properties of polyester woven fabrics which were coated with micronized perlite having three different particle sizes (10–38, 50–63, and 100–150 μm) at four different concentrations (20, 40, 60, and 80 g/kg) were investigated. The coating process was performed according to the knife‐over‐roll method. Thermal measurements were carried out with two different principles to evaluate contact and radiant heat transfer according to JIS R 2618 (testing method for thermal conductivity of insulating fire bricks by hot wire) and EN ISO 6942 (protective clothing‐protection against heat and fire‐method of test: evaluation of materials and material assemblies when exposed to a source of radiant heat), respectively. Perlite coating enhanced the thermal insulation property of fabrics. The lowest thermal conductivity coefficient and heat transmission factor (0.088 W/mK and 26.83%) values were obtained at the maximum concentration with the biggest size perlite. With the increasing perlite concentration, solar transmittance values decreased for all particle sizes while solar reflectance values increased. [ABSTRACT FROM AUTHOR]

Controlling thermal energy transfer at the nanoscale and thermal properties has become critically important in many applications since it often limits device performance. In this study, the effects on thermal conductivity arising from the nanoscale structure of free‐standing nanocrystalline silicon films and the increasing surface‐to‐volume ratio when fabricated into suspended optomechanical nanobeams are studied. Thermal transport and elucidate the relative impact of different grain size distributions and geometrical dimensions on thermal conductivity are characterized. A micro time‐domain thermoreflectance method to study free‐standing nanocrystalline silicon films and find a drastic reduction in the thermal conductivity, down to values below 10 W m–1 K–1 is used, with a stronger decrease for smaller grains. In optomechanical nanostructures, this effect is smaller than in membranes due to the competition of surface scattering in decreasing thermal conductivity. Finally, a novel versatile contactless characterization technique that can be adapted to any structure supporting a thermally shifted optical resonance is introduced. The thermal conductivity data agrees quantitatively with the thermoreflectance measurements. This study opens the way to a more generalized thermal characterization of optomechanical cavities and to create hot‐spots with engineered shapes at the desired position in the structures as a means to study thermal transport in coupled photon‐phonon structures. [ABSTRACT FROM AUTHOR]

A 12.3 inch FHD flexible AMOLED display module for vehicle application was produced and the heat dissipation was studied. Passive thermal management technology was investigated and a simplified steady heat transfer model was established to analysis the thermal properties of the vehicle AMOLED display module. The simulation results were good consistent with the measured data. By optimizing the structure and materials of heat dissipation, the surface temperature of the AMOLED display module with the luminance of 800 cd/m2 at full white pattern can be decreased to 42.5 °C which was 4.1 °C lower than that of without any dissipation films. [ABSTRACT FROM AUTHOR]

Gas‐assisted injection molding is a polymer processing technology in which a penetrating gas bubble hollows out a plastic part as it cools and solidifies within a mold. In this study, non‐isothermal gas injection experiments at high capillary number illustrate the effects of delay time in gas injection, tube diameter, capillary number, and temperature‐sensitive fluid viscosity and flow activation energy on coating thickness. Experiments with polybutene H‐300 and Dow Corning silicon oil (DC‐200) in stainless steel tubing (1.27 and 0.635 cm) demonstrated fractional coverage increasing from 0.6 to a maximum in the range of 0.63–0.83 at short delay times, then decaying toward 0.6 at long delay times upon approaching the cooled isothermal state. Further analysis is drawn from simulations based on a simple theoretical model incorporating one‐dimensional heat transfer with convection at the outer surface of the mold, non‐isothermal behavior of the viscous fluid, and radial velocity profiles in the one‐phase fluid flow region. Quantitative agreement is found between experimental and simulated results. Two‐dimensional modeling and simulation methods extend the prior results to illustrate transient axial and radial heat transfer as well as flow behavior with respect to the penetrating gas bubble within the fluid flow region. [ABSTRACT FROM AUTHOR]

For suitable design of equipment and process optimization, the determination of thermophysical properties of the raw materials is necessary. Therefore, this work was aimed at determining and modeling the density, specific heat, thermal diffusivity, and thermal conductivity of acid slurries of cassava bagasse used during its conversion into bioethanol. Experimental measurements were carried out in slurries with different mass fractions of cassava bagasse (0.00 to 0.10) and phosphoric acid (0.00 to 0.10) at temperatures from 278.13 to 318.13 K. Results obtained show that density varied from 986.5 to 1,029.3 kg∙m−3, specific heat from 3,830.0 to 4,142.6 J∙kg−1∙K−1, thermal diffusivity from 0.9624 × 10−7 to 1.5249 × 10−7 m2∙s−1 and thermal conductivity from 0.3825 to 0.6212 W∙m−1∙K−1. While density increased with increasing solids and acid content at decreasing temperature, the thermal properties decreased at higher solids and acid content and increased when heating the slurries. The values were well‐fitted to polynomial models with good accuracy (R2 > 0.921 and MRE < 1.75%), allowing the application of the models to obtain reliable and ready‐to‐use data for cassava bagasse processing. Thus, the data reported in this study can be used for designing and managing momentum, heat and mass transfer processes for enhancing bioethanol production from cassava bagasse. [ABSTRACT FROM AUTHOR]

Pellet heat transfer has always been one of the biggest limiting factors in its direct reduction process in the rotary hearth furnace (RHF). Therefore, strengthening its heat transfer process is very important for productivity in RHF. In this study, a coupling model of the carbon‐containing pellet reduction process considering porosity and chemical heat variation with intermediate media in its center was established. With the pellet radius R0 = 11 mm, the influence of the intermediate spherical medium radius r0, the offset position of the spherical medium ξ, and the materials used on the overall pellet reduction process were analyzed. The results showed that the presence of a spherical medium in the pellet center can increase the temperature inside the pellet, leading to it being more advantageous for reduction of the pellet. With the increase of the medium radius r0, it becomes more favorable for the pellet reduction process, as the spherical medium is more efficient for heat conduction. With the increase of the offset value ξ, the spherical medium acting as heat‐conducting material can allow the heat transferred to the pellet inside faster, which is also more favorable to the reduction process. In addition, when the spherical medium has a smaller effective volume heat capacity ρ∁p and a larger thermal conductivity k, it is more favorable for the pellet reduction process too. These results can serve as a reference for optimum pellet design in RHF. [ABSTRACT FROM AUTHOR]

The experimental study, thermal performance, and pressure drop of single-walled carbon nanotube (SWCNT) and graphene quantum dot (GQD) nanofluids in shell and tube heat exchanger with fin blade tubes are evaluated. The effects of the working fluid (water) volume flow rates (VÌ= 2.5-10 L/min), volume concentration of nanoparticles (Ï= 0.0%, 1%, 3%, and 5%), Reynolds number of working fluid (Re = 850-3300), and tube building (heat exchanger with fin blade tubes and without fin blade tube) have been analyzed. Results represent that with augmentation of volume concentration of SWCNT nanoparticle up to 1%, heat transfer rate increases by â5% and then up to 5% volume concentration of SWCNT nanoparticle decreased about 17%, also this calculation for GQD nanoparticle conducted and results represented decreasing 6% and approximately unchanged heat transfer rate, respectively. With regard to obtained results, heat transfer rate of heat exchanger can be improved by using the fin blades by 188%, compered without fin blade heat exchanger also most related increase for pressure drop of heat exchanger was recorded about 80% for 5% SWCNT of nanofluid. At the end, the mean enhancement in effectiveness of heat exchanger with various concentrations of SWCNT and GQD nanofluids and using the fin blades is about over 100% and 85%, respectively. In fact, the present study shows that applying the new finned tubes in the heat exchanger has more impact, related to the mentioned nanoparticles on the thermal properties of heat exchanger. [ABSTRACT FROM AUTHOR]

Thermal storage and transfer fluids have important applications in industrial, transportation, and domestic settings. Current thermal fluids have relatively low specific heats, often significantly below that of water. However, by introducing a thermochemical reaction to a base fluid, it is possible to enhance the fluid's thermal properties. In this work, density functional theory (DFT) is used to screen Diels–Alder reactions for use in aqueous thermal fluids. From an initial set of 52 reactions, four are identified with moderate aqueous solubility and predicted turning temperature near the liquid region of water. These reactions are selectively modified through 60 total functional group substitutions to produce novel reactions with improved solubility and thermal properties. Among the reactions generated by functional group substitution, seven have promising predicted thermal properties, significantly improving specific heat (by as much as 30.5%) and energy storage density (by as much as 4.9%) compared to pure water. [ABSTRACT FROM AUTHOR]

As the size of materials, particles, and devices shrinks to nanometer, atomic, or even quantum scale, it is more challenging to characterize their thermal properties reliably. Scanning thermal microscopy (SThM) is an emerging method to obtain local thermal information by controlling and monitoring probe–sample thermal exchange processes. In this review, key experimental and theoretical components of the SThM system are discussed, including thermal probes and experimental methods, heat transfer mechanisms, calibration strategies, thermal exchange resistance, and effective heat transfer coefficients. Additionally, recent applications of SThM to novel materials and devices are reviewed, with emphasis on thermoelectric, biological, phase change, and 2D materials. [ABSTRACT FROM AUTHOR]

Agitated drying of pharmaceuticals remains a challenging manufacturing step due to the simultaneous heat transfer, mass transfer, and physicochemical changes occurring during the process. This work focuses on the heat transfer component by implementing the discrete element method to model dry particles in a heated bladed mixer. Simulations varying material conductivities and impeller agitation rates were conducted to evaluate the influence on the mean bed temperature and distribution.The results indicated that increasing the agitation rate generally improved heat trans-fer up until a critical agitation rate where the rate of heat transfer plateaued. The magnitude of this improvement in heat transfer depended on the material's thermal properties. We observed three regimes: a conduction-dominated regime where particles heated quickly but with an annular temperature gradient, a granular convection-dominated regime where particles heated slowly but uniformly, and an intermediate regime. The results were nondimensionalized to enable predictions and help inform drying protocols. [ABSTRACT FROM AUTHOR]

Lattice materials provide unusual thermal and vibrational properties but not within the same structure. Thermal and vibrational multifunctionality is, however, crucial for thermomechanical applications such as automotive, aerospace, building, transportation, and energy infrastructure. In applications involving mobility, both high heat transfer and low mass are desired. Although there have been various efforts to design multifunctional lattice materials, the focus has largely remained on quasi‐static mechanical and thermal properties or mechanical and vibrational properties. Herein, designs of realizable lattice materials are reported, which are inherently thermally resistive, with vastly improved thermal conductance and omnidirectional phononic band gaps. By redesigning the truss structures to serve as interconnected heat pipes, a three‐order‐of‐magnitude improvement in the specific thermal conductance is found. Nodal masses at truss junctions are further used to obtain full vibrational band gaps. It is shown that it is possible to independently tune vibrational and thermal properties within the same structure. This work provides background for the design and fabrication of multifunctional lattice materials that simultaneously prevent structural vibrations and enhance heat conduction. [ABSTRACT FROM AUTHOR]

To improve the performance and increase the lifetime of oil‐filled transformers, the thermal and dielectric properties of the transformer oil should be enhanced. Recently, nanotechnology was used as an effective science in the field of transformer oil development. In this study, barium titanate (BT) nanoparticles were inserted into the base transformer oil by a concentration of 0.005 g/L as an individual nanofluid sample (INFS). This insertion enhances the heat transfer coefficient by 33% but the breakdown voltage (BDV) was decreased by >10%. To overcome this problem of dielectric properties degradation, other three hybrid nanofluid samples (HNFS) were prepared using three different types of metal oxide (MO) nanoparticles; titania, alumina, and silica. These samples were prepared by adding a concentration 0.01 g/L of MO nanoparticles together with 0.005 g/L of BT nanoparticles into the oil. The thermal and dielectric properties of HNFS were measured to study the behaviour of nanoparticles hybridisation on transformer oil properties. HNFS using titania nanoparticles provided the best composition regarding either BDV or heat transfer coefficient. Dynamic light scattering (DLS) technique was used to evaluate the particle size distribution of hybrid nanoparticles and to clarify the corresponding physical mechanisms behind the obtained enhancement. [ABSTRACT FROM AUTHOR]

The thermal diffusivity is the key parameter that controls near‐surface temperature where periodic temperature variation is progressively attenuated and delayed with depth. This article presents the results of apparent thermal diffusivity using temperatures recorded by a bedrock temperature measurement network in the fault zones of western Sichuan. High sensitivity temperature sensors (10−4 K) were installed at a maximum depth reaching 30 m. The apparent thermal diffusivities were deduced from both amplitude damping and phase shifting of annual temperature variations between two different depths. Under pure conduction, the thermal diffusivity determined through the phase method (αΦ) should be equivalent to that determined through the amplitude method (αA), whereas effects of the upward (downward) water flow are evidently reflected in the amplitude decay to make αΦ larger (lesser) than αA. The discrepancy between αΦ and αA can thus be a tracer of water movement or convective heat transfer. The calculated αΦ of the measurement stations varies from 1.22 × 10−6 to 3.00 × 10−6 m2/s, and the estimated αA ranges from 0.93 × 10−6 to 2.41 × 10−6 m2/s. Two regimes of heat transfer underground were suggested from the results. Conductive heat transport prevails over the nonconductive processes at five stations, which is characterized by αΦ coincident with αA for the same depth pair. On the contrary, the values of αΦ differ from αA at six stations in the intersection area of the Y‐shaped fault system, implying that convective heat transfer also plays a comparably important role. This finding is consistent with the hot springs distribution of the area. The results also indicate that water moves upward with an average Darcy velocity of approximately −1 × 10−7 m/s in this region. Our research provides new evidence for the hydrothermal activity in the fault zones at the eastern margin of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

This study aimed at optimizing the injection molding process of an automotive oil filter housing made from PA6.6. Mass accumulations in its design intensely increased the cooling time. In a first successful approach, a copper alloy mold insert (λ = 106 Wm−1 K−1) that contains two externally cooled heat‐conducting copper pins (λ = 310 Wm−1 K−1) was installed. We hypothesized that a biomimetic cooling channel structure in a steel mold insert would even perform superior. Using simulation software Sigmasoft® v5.0, the mold insert materials (steel Bohler X20Cr13, Ampcoloy® 83), the plastics grade PA66‐GF35 (λ = 0.27 Wm−1 K−1 or λ = 0.40 Wm−1 K−1), and three cooling designs were evaluated for their impact on cooling the hot spots in the part: the copper pin‐system, a conformal cooling channel, and blood‐vessel like channels. In the latter, the major artery branches into two sub‐arteries, which further divide into two capillary tubes each. The capillaries merge into two sub‐veins and those fuse in the major vein again. As expected, the plastics heat conductivity dominates the cooling. The biomimetic (blood‐vessel) channels, as hypothesized, cooled the major hot spot more efficient than the conformal channel and the copper pin system do. In detail, compared to the heat‐conductive insert, the cycle time may be reduced by 10 s, in spite of the lower heat conductivity λ (23.5 Wm−1 K−1) of the steel insert. Using the biomimetic (blood‐vessel) structure in a heat‐conductive mold insert would reduce the cycle time by a further second. However, raising the heat conductivity of the plastics would save another 15s. Experimental tests proved the cooling efficiency. Nevertheless, cooling channels only perform well, if they are close enough to the mass accumulation. In conclusion, transferring biologic cooling structures to injection molding seems to be promising. Ongoing advances in Additive Manufacturing will help to efficiently implement these structures into mold inserts for injection molding. POLYM. ENG. SCI., 59:E180–E188, 2019. © 2018 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers. [ABSTRACT FROM AUTHOR]

A procedure for the metrological evaluation of the self‐heating effect in resistance thermometers is reported. This procedure is applied to different designs of resistance thermometers, used for meteorological and climate applications. The study of the self‐heating effect variation with the applied electrical current, temperature and different surrounding environments is described, as well as the influence of wind speed on the self‐heating effect. Variation of the standard deviation of the thermometer resistance mean with the applied electrical current, at different temperatures and with different external environments. [ABSTRACT FROM AUTHOR]

It is interesting to compare the residual strength of laminated carbon fiber reinforced polymer under thermal environments with finite heating rate, and laser irradiation with rapid heating rate. In these two conditions, heating rates are varied in two orders of magnitude, and thermally‐induced damage mechanisms are quite different, which may influence the performance of residual strength. Systematic experiments are performed to obtain the tensile failure behavior of laminated carbon fiber reinforced epoxy composites at different temperatures with a heating rate of about 102°C/min. In comparison, composite samples are subjected to laser irradiations of different power densities and then tested for residual strengths, the laser induced heating rate is above 104°C/min. Experimental results indicate that the residual strength decreases with the increase of heating temperatures and laser power densities, however the damage mechanisms for conventional heating are thermal pyrolysis, oxidation and delamination, whereas the main damage mechanisms for laser irradiation are thermal pyrolysis and fiber ablation. The experimentally obtained residual strength and modulus are also compared with those predicted by theoretical model. POLYM. ENG. SCI., 58:2311–2319, 2018. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Summary: Understanding the heat transfer mechanism through a clothed man system in extreme environments is of great significance for human thermal protection. Three‐dimensional heat transfer models were developed based on the computational fluid dynamics considering a real‐shape human body in this study. The influences of air gap width, clothing thickness, and emissivity on the heat transfer within a dressed manikin exposed to flash fire were investigated. Simulated results indicated that the heat transfer in the air space was more complicated on the garment level than the fabric, because of the varying relative positions between different body segments and the heat source, as well as the ventilation openings. Increasing the fabric thickness was an effective method to reduce the transferred energy, which could remarkably lower the skin temperature. Decreasing both of the surface and backside emissivity from 0.9 to 0.3 could increase the protective performance, where surface emissivity reduction was recommended since the decrease of clothing temperature could minimize the risks of fabric degradation. The purpose of assuming the uniform air gap was to perform the parametric study, which was unrealistic indeed. The model with real clothing shape will be developed and investigated in the near future. [ABSTRACT FROM AUTHOR]

Abstract: Subsurface temperatures in polar environments control geomorphic, hydrologic, and biologic processes and ground ice stability. Most studies of the thermal regime in permafrost areas have been developed for the Arctic where interest and concern focus on permafrost thawing. In contrast, this study focuses on soils in the McMurdo Dry Valleys of Antarctica where conditions are much colder and drier, and long‐term persistence of ground ice is of interest including as an analog site for Mars. The soil temperature in Beacon Valley, one of the McMurdo Dry Valleys, has been modeled using the surface temperature, measured heat capacity, and temperature‐dependent thermal conductivity and compared to continuous, high‐resolution measurements of temperatures for a decade down to 19.6‐m depth. For the temperature range of −47.9 to 7.5 °C at our study site, the heat capacity of the dry soil ranges from 580 to 690 J · kg−1 · K−1, thermal conductivity from 0.22 to 0.27 W · m−1 · K−1, and the calculated thermal diffusivity from 0.23 to 0.25 mm2/s. Both the finite difference method and the finite volume method are used to solve the 1‐D heat diffusion equation; the finite volume method‐modeled temperature most closely approximates the measured temperature at all depths with average differences ranging from 0.01 to 0.03 °C. The latent heat contribution of documented episodic snowmelt events and of modeled changes in ice content due to condensation or sublimation is negligible. This study can be applied readily to thermal regimes of similar systems where subsurface temperature measurements are not available such as on Mars. [ABSTRACT FROM AUTHOR]

A rigorous microstructural analysis of porous mullite materials developed using novel shaping strategies based on the starch consolidation casting, and their thermal properties in relation to the processing and starch type were accomplished in view of their use as thermal insulators. In order to characterize the size and morphology of pore, basic size and 2D shape factors, and global 3D stereological parameters were determined using microscopy techniques. Results indicated that the porosity volume, pore connectivity degree, and mean free path were the determining factors of the lowest heat transfer by conduction registered in materials prepared with cassava starch. This material is the best candidate to be used in thermal insulation. [ABSTRACT FROM AUTHOR]

Nanofluids are emerging as alternative fluids for heat transfer applications due to enhanced thermal properties. Several correlations are available in open literature for heat transfer coefficient (HTC) and thermophysical properties of nanofluids. Reliability of correlations that use effective properties for estimation of HTC needs to be checked. Comparison of experimental HTC and that estimated from existing correlations is the main objective of the present study. An empirical correlation is developed with experimental data of the HTC for zinc-water and zinc oxide-water nanofluids. Experimental HTC is compared with that estimated from developed correlation and existing correlations. The range of Re considered for the study is 4000 to 18,000. Comparison indicated large deviation in experimental values and the values estimated from existing correlations. Based on comparison results, it can be concluded that the single-phase models of forced convective heat transfer cannot be extended to nanofluids. [ABSTRACT FROM AUTHOR]

ABSTRACT Carbon nanotubes (CNTs) filled perfluoroalkoxy (PFA) films with the thicknesses of about 10 μm have been prepared via blade coating. Both of the CNTs and PFA are aqueous dispersion, which are favorable for the uniform dispersion of fillers into the matrix. The morphology, direct current (DC) resistivity, electrothermal property, and thermal diffusivity of the composite films were studied. We find out that the fraction of CNTs played a vital role in the heating property and thermal transferring capacity of the composite films. Under the input voltage of 110 V, the temperature of PFA composite film with 15 wt % CNT reached to 200 °C, and the thermal diffusivity was about 3.3 mm2/s. We believe these CNTs/PFA films are promising alternatives to work as flexible electric heating devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44782. [ABSTRACT FROM AUTHOR]

Thermochemical splitting of CO2 via a ceria-based redox cycle was performed in a solar-driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+-doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200-1950 K and subsequently re-oxidized with CO2 at 950-1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm-sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm-sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+-doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1263-1271, 2017 [ABSTRACT FROM AUTHOR]

This study first presents a subtle thermal-chlorination strategy for a universal transformation of abundant 2D metal carbides (M xC y, e.g., Cr3C2, Mo2C, NbC, and VC) to 2D graphene and M-self-doped graphene (MG). The as-obtained MG endows a transparent sheet architecture of one to four atomic layers. Simultaneously, MG with different M amounts is synthesized by tuning the chlorination parameters. Among them, the novel and representative Cr-self-doped graphene with optimal Cr amount (4.81 at%) demonstrates the outstanding electrochemical performance. It presents an energy density of 686 W h per kg electrode and a power density of more than 391 W per kg electrode as anode material of Li ion batteries, and four-fold activity against the commercial iridium oxide electrode toward oxygen evolution reaction as well as a comparable oxygen reduction reaction performance to the commercial platinum catalyst. Moreover, this method is readily scalable to produce graphene and MG electrode materials on industrial levels. [ABSTRACT FROM AUTHOR]

An advanced hybrid lumped parameter code for the simulation of Pulsating Heat Pipes is developed. Being able to simulate transient operative conditions and removing common physical simplified assumptions, it represents a step forward with respect to the present models of passive two-phase systems. Mass, momentum and energy balances account for the thermal and fluid-dynamics phenomena. Heterogeneous and homogeneous phase changes are directly integrated. In addition, a fitting correlation for the wall/vapour heat transfer coefficient is implemented and tuned against experimental data in order to evaluate the influence of the liquid film on conjugate heat transfer. The resulting numerical tool have been validated against experimental data achieved testing a copper pulsating heat pipe during the 58th ESA Parabolic Flight Campaign in several operative conditions and transient gravity levels. The predicted results show very good matching with the actual thermo-physical behaviour of the system. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Boiling of a pure fluid inside the rotor-stator cavities of a stator-rotor-stator spinning disc reactor (srs-SDR) is studied, as a function of rotational velocity ω, average temperature driving force [ABSTRACT FROM AUTHOR]

Plate cooling is a complex process so that it cannot be described by a fixed model. So, the mathematical model requires self-adaptive ability to comply with the various parameters such as gauges and temperatures of plates. Considering the effect of influence factors on cooling process, an online variable scale grid (VSG) model for cooling is developed. VSG model builds a multi-dimension space system where each dimension is determined by the effect of each factor on heat transfer. Every plate can find a corresponding point in the space, according to its own process conditions. To guarantee the higher precision of temperature control, it adopts dimensionless treatment for all the factors to avoid the errors caused by different physical units. In order to reduce the computational cost, the technologies of finite element meshing and centroid calculation have been applied. When a new plate comes, the correlations between the new one and historical samples, centroids are described by Euclidean distance. Finally, the target value is estimated through the distance-weighted average method. The results of experiments and applications with real industrial data show that the proposed VSG is effective in the plate cooling control and has a wide application prospect. [ABSTRACT FROM AUTHOR]

Two new isostructural iron(II) spin-crossover (SCO) framework (SCOF) materials of the type [Fe(dpms)2(NCX)2] (dpms=4,4′-dipyridylmethyl sulfide; X=S ( SCOF-6(S)), X=Se ( SCOF-6(Se))) have been synthesized. The 2D framework materials consist of undulating and interpenetrated rhomboid (4,4) nets. SCOF-6(S) displays an incomplete SCO transition with only approximately 30 % conversion of high-spin (HS) to low-spin iron(II) sites over the temperature range 300-4 K ( T1/2=75 K). In contrast, the NCSe− analogue, SCOF-6(Se), displays a complete SCO transition ( T1/2=135 K). Photomagnetic characterizations reveal quantitative light- induced excited spin-state trapping (LIESST) of metastable HS iron(II) sites at 10 K. The temperature at which the photoinduced stored information is erased is 58 and 50 K for SCOF-6(S) and SCOF-6(Se), respectively. Variable-pressure magnetic measurements were performed on SCOF-6(S), revealing that with increasing pressure both the T1/2 value and the extent of spin conversion are increased; with pressures exceeding 5.2 kbar a complete thermal transition is achieved. This study confirms that kinetic trapping effects are responsible for hindering a complete thermally induced spin transition in SCOF-6(S) at ambient pressure due to an interplay between close T1/2 and T(LIESST) values. [ABSTRACT FROM AUTHOR]

The effects of temperature and material deposit on workpiece material removal spatial uniformity during optical pad polishing are described. Round and square-fused silica workpieces (25-265 mm in size) were polished on a polyurethane pad using ceria slurry under various conditions. Using a nonrotated workpiece on a rotating lap, elevated temperatures (as measured by IR imaging), due to frictional heating at the workpiece-lap interface, were observed having a largely radial symmetric profile (relative to the lap center) on both the workpiece and lap with a peak temperature corresponding to the workpiece center. A 3D steady-state thermal model of the polishing process, which accounts for the frictional heating and effective heat transfer from various surfaces, quantitatively describes the observed thermal profiles. The temperature spatial uniformity, which affects the material removal spatial uniformity, can be significantly improved using a rotated workpiece and a specially designed compensating septum during polishing. Next, using a rotating workpiece and lap, the workpiece surface develops two types of mid-range structure: (1) fine ripples (sub-mm scale length) that run circumferentially with respect to the lap, which have been attributed to microscopic islands of slurry on the lap leading to radial material removal nonuniformities; and (2) a center depression (cm scale length) which has been attributed to nonlinear slurry & glass products buildup at a specific radial lap location. A polishing simulator model (called Surface Figure or SurF), which accounts for workpiece wear, pad wear, and now deposition on the pad, correctly simulates the preferential material deposit on the pad and the center depression structure developed on the workpiece. Strategies, such as time averaging through kinematics and diamond conditioning, for preventing both these nonuniformities are demonstrated. [ABSTRACT FROM AUTHOR]

Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation. Methods: A meshless point collocation solver is used for the numerical solution of the governing equations. The results obtained are used by the DMD method for forecasting the numerical solution faster than the meshless solver. The procedure is first validated against analytical and numerical predictions for simple problems. The DMD method is then applied to three-dimensional simulations that involve modeling of tumor ablation and account for metabolic heat generation, blood perfusion, and heat ablation using realistic values for the various parameters. Results: The present method offers very fast numerical solution to bioheat transfer, which is of clinical significance in medical practice. It also sidesteps the mathematical treatment of boundaries between tumor and healthy tissue, which is usually a tedious procedure with some inevitable degree of approximation. The DMD method provides excellent predictions of the temperature profile in tumors and in the healthy parts of the tissue, for linear and nonlinear thermal properties of the tissue. Conclusions: The low computational cost renders the use of DMD suitable for in situ real time tumor ablation simulations without sacrificing accuracy. In such a way, the tumor ablation treatment planning is feasible using just a personal computer thanks to the simplicity of the numerical procedure used. The geometrical data can be provided directly by medical image modalities used in everyday practice. [ABSTRACT FROM AUTHOR]

The snowcover energy balance is typically dominated by net radiation and sensible and latent heat fluxes. Validation of the two latter components is rare and often difficult to undertake at complex mountain sites. Latent heat flux, the focus of this paper, is the primary coupling mechanism between the snow surface and the atmosphere. It accounts for the critical exchange of mass (sublimation or condensation), along with the associated snowcover energy loss or gain. Measured and modelled latent heat fluxes at a wind-exposed and wind-sheltered site were compared to evaluate variability in model parameters. A well-tested and well-validated snowcover energy balance model, Snobal, was selected for this comparison because of previously successful applications of the model at these sites and because of the adjustability of the parameters specific to latent heat transfer within the model. Simulated latent heat flux and snow water equivalent (SWE) were not sensitive to different formulations of the stability profile functions associated with heat transfer calculations. The model parameters of snow surface roughness length and active snow layer thickness were used to improve latent heat flux simulations while retaining accuracy in the simulation of the SWE at an exposed and sheltered study site. Optimal parameters for simulated latent heat flux and SWE were found at the exposed site with a shorter roughness length and thicker active layer, and at the sheltered site with a longer roughness length and thinner active layer. These findings were linked to physical characteristics of the study sites and will allow for adoption into other snow models that use similar parameters. Physical characteristics of wind exposure and cover could also be used to distribute critical parameters in a spatially distributed modelling domain and aid in parameter selection for application to other watersheds where detailed information is not available. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A combined heat-pulse and sensible heat balance method can be used to determine evaporation using temperature measurements and thermal property estimations. The objective of this study was to investigate the applicability of the combined heat-pulse and sensible heat balance method by comparing laboratory experimental data to both an analytical and a multiphase heat and mass transfer model. A bench-scale laboratory experiment was performed to measure soil thermal and hydraulic properties at ine spatial and temporal resolutions. Comparisons of experimental and numerical results conirmed the applicability of the heat-pulse and sensible heat balance methods to determine evaporation rates. Results showed close agreement with experimental water loss measurements. This study demonstrated the ability and versatility of using the heat-pulse and sensible heat balance methods in numerical heat and mass transfer models to determine evaporation rates. Calculated soil thermal properties were in 93.4 and 97.5% agreement with experimental results for water content values >0.05. Deviations were observed at low water contents due to sensor sensitivity. The calculated evaporation rates yielded cumulative water losses that were 96.8 and 97.7% in agreement with experimentally measured weight loss data. Late Stage 1 evaporation was overestimated due to observed temperature rises by two of the heat-pulse probes. Despite this, the combined heat-pulse and sensible heat balance method is a powerful tool that can be used to determine evaporation rates in situ. [ABSTRACT FROM AUTHOR]

A 1-D through-the-thickness transient heat transfer model is built to simulate the curing process of thick-walled glass-fibre-reinforced anionic polyamide-6 (APA-6) composites. The temperature and the degree of polymerisation through the thickness of the composite are calculated and compared to the experimentally obtained results. The kinetic models describing the polymerisation behaviour of APA-6 are implemented in the model. The kinetic model not taking into account the convection in the polymerisation process shows the best results. It is found that the predicted temperature profiles agree well with the experimental data. [ABSTRACT FROM AUTHOR]

Anisotropic thermal transport in a crosslinked polyisoprene (natural rubber) subjected to uniaxial elongation is investigated experimentally. Using a novel optical technique based on forced Rayleigh scattering, two components of the thermal diffusivity tensor are measured as a function of stretch ratio. The thermal diffusivity is found to increase in the direction parallel, and decrease in the direction perpendicular, to the stretch direction. The level of anisotropy for the natural rubber is substantially lower than that reported by Tautz 50 years ago but comparable to that found in our previous studies on molten polymers, quenched thermoplastics, and other crosslinked elastomers. Thermal diffusivity data along with measurements of the tensile stress were used to evaluate the stress-thermal rule, which was found to be valid over the entire range of stretch ratios. In contrast, failure of the stress-optic rule was observed at stretch ratios well below the largest value at which the stress-thermal rule was valid. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and stretch of polymer chain segments. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 [ABSTRACT FROM AUTHOR]

With the ever-increasing depth of mines, the management of heat has become a key issue for their design and operation. There are two main sources of heat: heat transfer from the rock mass into the mine workings and heat associated with mining operations. The principles of heat transfer from the rock mass are discussed and basic relationships presented. Sources of heat linked to mining operations are discussed. It is shown that in deep-level mines, heat transfer from the rock mass accounts more than 75 % of total mine heat load. In highly mechanized coal mines, heat from the use of mining machinery is also significant. Some models of heat flow prediction for deep gold mines are presented. It is shown that in the case of deep mines, control of heat flow is more important than increasing refrigeration capacity. Examples of heat flow management methods are given. Durch die ständig zunehmende Teufe der Abbaubetriebspunkte wird die Erdwärme zu einem Schlüsselfaktor hinsichtlich Planung und Betrieb von tiefliegenden Bergwerken. Es gibt zwei Hauptwärmequellen, einerseits den Wärmeübergang vom umgebenden Gebirge in die Grubenbaue sowie wärmeproduzierende Arbeitsvorgänge unter Tage. Dieser Beitrag erörtert die Grundsätze des Wärmetransfers aus dem Gebirge und stellt grundlegende Zusammenhänge dar. Darüber hinaus wird auf Wärmequellen im Bergbaubetrieb eingegangen. In tiefliegenden Bergwerken trägt der Wärmeübergang aus dem Gebirge mehr als 75 % zur gesamten Wärmebelastung bei, im Fall von hoch mechanisierten Kohlebergwerken ist die Wärme von Vortriebs- und Gewinnungsmaschinen signifikant. Einige Modelle für die Voraussagung von Wärmeströmen in tiefliegenden Goldbergwerken werden dargestellt. Es zeigt sich, dass die Kontrolle von Wärmeströmen wichtiger ist als die Erhöhung der Kühlleistung. Einige Beispiele zeigen Möglichkeiten zum Umgang mit Wärmeströmen auf. [ABSTRACT FROM AUTHOR]

Reported experimental and computational results confirm that both the flow features and heat transfer rates inside a condenser depend on the specification of inlet, wall, and exit conditions. The theoretical and experimental results presented in this paper allow us to propose important exit condition based categorization of these flows. Of these, category II flows are defined to be cases for which exit pressures are left unspecified. However it is shown here that steady flows under specified exit pressure conditions (category I flows) are more stable and can be more easily achieved under all conditions (normal or zero-gravity). Existence of self-selected exit pressure conditions for unspecified exit condition cases (category II flows) are more difficult to achieve and are often limited to gravity driven flows. In practice, however, special hardware arrangements are required for repeatable realization of both these categories of flow. If this is not so, one often has an inadvertent category I flow (flows with specified exit pressure) without the explicit knowledge of the exit pressure value. For microgravity situations, the remedy is to run condensers under suitably specified inlet and exit pressures (category I conditions) as well as a proper cooling strategy (i.e., proper wall temperature variations). [ABSTRACT FROM AUTHOR]

Diffusion-based coupled soil heat and water transfer theory includes capability to describe transient behavior. Unfortunately, laboratory tests of theory typically include a single initial water content distribution with a single set of boundary conditions, rather than providing a set of experimental conditions with a range of measurements for comparison with predictions. Agreement between theory and measurements can result from calibration, but this provides an incomplete test of theory. The objective of this work was to test diffusion-based coupled heat and water transfer theory by comparing theory-based predictions with measured transient temperature and water content distributions. Data from a single boundary condition were used for calibration of each of two soils, silt loam and sand. Subsequent testing was performed at additional boundary and initial conditions using measurements from the same soil. Results indicate that the theory can be calibrated for a single boundary condition with adjustment of soil saturated hydraulic conductivity and/or the vapor enhancement factor, which adjust the liquid and vapor fluxes, respectively. For silt loam, calibration reduced Root Mean Square Error (RMSE) by 67 and 18% for water content and temperature distributions, respectively. For sand, RMSE was reduced by 14 and 46% for water content and temperature, respectively. Using this calibration, there was agreement between calculated and measured distributions for additional boundary and initial conditions with RMSE ⩽ 0.03 m3m-3 and 1.28°C for water content and temperature distributions, respectively. However, when the boundary temperature gradient was instantly reversed, noticeable differences occurred between measured and calculated patterns of heat and moisture redistribution. The theory described observations well when boundary temperature conditions were changed gradually, but results suggested a need for further development of coupled heat and water transfer theory combined with testing under transient conditions to make improvements in the description of transfer mechanisms. [ABSTRACT FROM AUTHOR]

The finite element method is used to examine the thermal properties of functional ceramics, which were used in metallurgical processes during antiquity. Based on the ceramics' microstructure a model is developed considering the impact of porosity and inclusions and the heat transfer from ceramics to environment. An example of a Bronze Age copper smelting furnace from Cyprus is presented. Particularly the influence of pore shape and pore orientation on the thermal conductivity is investigated. Temperature development in the entire furnace is simulated and compared with estimations of the firing temperature in particular areas of the furnace. [ABSTRACT FROM AUTHOR]

The article presents research findings from a study of South Korean primary-school students aged 4-11 years and their understanding of heat and temperature. The study was conducted by interviewing 154 students and asking questions related to three main concepts of understanding heat and temperature: conceptions of heat equilibrium, thermal insulation, and temperature. Many students showed tendencies to use relevant life experience to form opinions. Students' common alternative conceptions and the logic behind them are discussed.

This paper characterizes the metamorphic thermal structure of the Higo Metamorphic Complex (HMC) and presents the results of a numerical simulation of a geotherm with melt migration and solidification. Reconstruction of the geological and metamorphic structure shows that the HMC initially had a simple thermal structure where metamorphic temperatures and pressures increased towards apparent lower structural levels. Subsequently, this initial thermal structure has been collapsed by E–W and NNE–SSW trending high-angle faults. Pressure and temperature conditions using the analysis of mineral assemblages and thermobarometry define a metamorphic fieldP–Tarray that may be divided into two segments: the array at apparent higher structural levels has a low-dP/dTslope, whereas that at apparent lower structural levels has a high-dP/dTslope. This composite array cannot be explained by heat conduction in subsolidus rocks alone. Migmatite is exposed pervasively at apparent lower structural levels, but large syn-metamorphic plutons are absent at the levels exposed in the HMC. Transport and solidification of melt within migmatite is a potential mechanism to generate the composite array. Thermal modelling of a geotherm with melt migration and solidification shows that the composite thermal structure may be formed by a change of the dominant heat transfer from an advective regime to a conduction regime with decreasing depth. The model also predicts that strata beneath the crossing point will consist of high-grade solid metamorphic rocks and solidified melt products, such as migmatite. This prediction is consistent with the observation that migmatite was associated with the very high-dP/dTslope. The melt migration model is able to generate the very high-dP/dTsegment due to the high rate of heat transfer by advection. [ABSTRACT FROM AUTHOR]