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Direct decomposition of H 2 S into H 2 and S is an attractive alternative to the Claus process, because CO x -free H 2 and S can be simultaneously recovered from an abundant and toxic waste gas, which has huge social economic and ecological environmental benefits. However, it is still a great challenge to achieve the direct H 2 S decomposition reaction with high efficiency due to the thermal equilibrium limitation. Herein, a core-shell structured Mo x C@ZrO 2 was developed as novel microwave catalyst for microwave catalytic H 2 S decomposition. More specifically, the H 2 S conversion over Mo x C@ZrO 2 catalyst is as high as 99.9% at 650 °C, which immensely surpasses the H 2 S equilibrium conversion (6.1% at 650 °C). This study provides an effective strategy for the design of highly active microwave catalysts, and supplies a strategy for efficiently catalytic decomposition of H 2 S waste and recovering high-value hydrogen and sulfur at lower reaction temperatures. [Display omitted] • H 2 S conversion is highly up to 99.9% at 650 °C under microwave irradiation. • Mo x C@ZrO 2 display excellent catalytic performance at low temperature in the MCRM. • Catalytic performance in the MCRM is much higher than that in the CRM. • Microwave irradiation can break chemical equilibrium of H 2 S decomposition reaction. [ABSTRACT FROM AUTHOR]

Temperature uniformity is a critical parameter in solid oxide fuel cells (SOFCs) since it directly impacts thermal stress, material degradation and output performance. Effective thermal management typically aims to achieve a minimal temperature gradient, especially within a SOFC stack assembled by numerous single cells. In this study, numerical simulations of various boundary conditions and cell designs are performed to investigate thermal uniformity in methane-rich internal reforming SOFCs, which can be utilized as a guidance for design and operation in practical application. The results indicate that the fuel gas with a 5 % mole fraction of methane is more effective in enhancing thermal uniformity through reforming cooling effect at the electrolyte compared to only a 1 % mole fraction. It is strongly recommended in cell design to maintain the ratio of the cell's length to its width (R cell) greater than or equal to 1.0 considering its better thermal uniformity. However, both increasing the ratio of channel width to rib width (R c-r) and decreasing the ratio of channel height to channel width (R H-W) have been demonstrated to deteriorate temperature uniformity. Within this study, increasing the backpressure to 1.5 bar is found to result in a 16.7 % reduction in the maximum temperature difference across the electrolyte when compared to that at atmospheric pressure. It is also advisable to operate at the inlet temperature ranging from 973 K to 1023 K for a more uniform temperature distribution within the SOFC. [Display omitted] • The dry reforming of methane is considered in thermal equilibrium analysis. • Effects of flow filed structure and operating parameters are investigated. • Operating parameters affect system efficiency and thermal uniformity differently. • There is a sweet spot for the effects of inlet temperature on thermal uniformity. [ABSTRACT FROM AUTHOR]

Centrifugal Nuclear Thermal Propulsion is a second-generation propulsion concept currently being researched to succeed traditional solid core nuclear thermal propulsion. Current efforts across the space industry are focusing on development of technologies for enabling manned flight to Mars and scientific missions to the outer planets. To enable these types of mission's direct injection trajectories are needed to decrease exposure to astronauts and scientific payloads to the harsh environment of space. Current efforts in nuclear thermal propulsion have shown great promise in higher specific impulses ∼900 s, but even these levels of specific impulse fall short for manned Mars missions with durations less than two years or direct injection to orbit of the outer ice giants Uranus and Neptune without the use of gravity assists. High performance nuclear thermal propulsion has been proposed using bubble through nuclear reactors to reach specific impulses as high as 1800 s, however significant challenges exist to prove the feasibility of such a system. One of the major challenges is the fluid mechanics within the core of the engine since little is known about uranium in the liquid phase. An experimental study has been conducted to better understand the fluid dynamics to better inform the thermodynamic and nucleonic models. Using the data from the experiment, high-fidelity simulations have been developed to predict the fluid dynamics of the uranium fuel. This information can then be further fed into thermodynamics models in development to predict core temperatures and system behaviour. The validated models show that small bubbles reach thermal equilibrium, and high centrifugal forces and surface tension assist in confining the molten uranium within the reactor core. Injector methods suggest feasible configurations to encourage bubble flow while minimizing backflow of the propellant, motivating further study of Centrifugal Nuclear Thermal Propulsion based systems. • Galinstan (Ga67In20.5Sn12.5) was determined to be a suitable uranium simulant for bubble formation. • High Speed Radiography was used to determine bubble characteristics using machine learning algorithm. • Hydrogen bubbles in uranium rapidly reach local equilibrium with diameters of 0.266 mm and reaching velocities of 16 m/s. • To date all research indicates that a centrifugal nuclear thermal rocket is feasible. [ABSTRACT FROM AUTHOR]

The non-equilibrium spectra of shock-heated nitrogen in the UV-visible range are investigated in a detonation driven shock tube. Spectral identification indicates that the main contributors to the spectra are molecular radiation of N 2 (2+) and N 2 + (1-). Vibrational and rotational temperatures of N 2 (C) and N 2 + (B) are determined through spectral fitting. The post-shock spectra of pure nitrogen are obtained for shock velocities ranging from 6.82–9.00 km/s and P 0 = 30–200 Pa at the shock arrival time. Differences between vibrational and rotational temperatures of N 2 (C) and N 2 + (B) are observed, suggesting that nitrogen is in a non-equilibrium state at shock arrival moment. Time-resolved spectra are obtained within varying delay times of 0– 2. 0 μ s at P 0 = 200 Pa and shock velocity of V sw = 6.60 km/s. Time-resolved temperatures are determined to illustrate the time-resolved non-equilibrium characteristics of nitrogen at high temperature. It is observed that the non-equilibrium characteristics of nitrogen gradually weaken with increasing time and the thermal equilibrium was not obtained within 2. 0 μ s. Finally, the time-resolved temperatures are compared with CEA (Chemical Equilibrium with Applications) prediction, revealing that the difference in temperature between the experiment and the CEA equilibrium calculation decreases as time increases. • The radiative spectra of nitrogen are obtained in shock tube with shock velocity of 6.5–9.0 km/s. • The shock velocity-dependent non-equilibrium characteristics of nitrogen are revealed. • The time-resolved non-equilibrium characteristics in the post-shock region are studied. • The non-equilibrium effects of N 2 (C) and N 2 +(B) are obtained and analyzed. [ABSTRACT FROM AUTHOR]

Standardizing hydrogen refueling station metering management promotes the economic and safe development of the hydrogen energy industry. In this study, by modifying the original equipment in hydrogen refueling stations, the real causes of hydrogen metering inaccuracy are experimentally investigated, and the effectiveness of the corresponding improvement measures is verified. While ensuring the accuracy of hydrogen metering, a segmented hydrogen loss rate calculation method has been proposed, which can assist in leak detection. The results show that the degree of variation in ambient temperature is the main factor affecting the metering accuracy of the PVT method, which is related to the difference in the rate of temperature rise within the hydrogen storage vessel and hydrogen piping. Differing from vehicle gas cylinders, the hydrogen tube bundle of the trailer does not produce a significant thermal equilibrium effect after filling, but the hydrogen metering errors are still not negligible because of sensitivity differences between pressure and temperature gauges and its large volume. Moreover, adding thermal insulation measures near the temperature gauge and improving the accuracy of the gauges can effectively reduce hydrogen metering errors. [Display omitted] • The causes of hydrogen metering inaccuracy using PVT method were analyzed. • The metering errors of HRSs quantified by full-scale experiments. • Two improvements for the accuracy of hydrogen metering were proposed and verified. • Application of the new hydrogen loss rate calculation method benefits leak detection. [ABSTRACT FROM AUTHOR]

Mullite fiber-based porous ceramics is one of the most commonly used high-temperature insulation materials. However, how to further reduce the thermal conductivity and improve the strength of such materials has been a challenge in the field of high-temperature insulation. In this paper, mullite micro/nano fiber-based porous ceramic was prepared by introducing mullite nanofibers into mullite microfiber-based porous ceramics and the effect of microfiber/nanofiber weight ratio on the samples properties were characterized and analyzed. Results showed that the compressive strength and high-temperature thermal insulation properties of the porous ceramics increased significantly with an increase in the nanofiber content. For the porous ceramics with similar density (about 0.50 g/cm3), the compressive strength of the sample with a microfibers/nanofibers weight ratio of 1:2 was 1.43 MPa, which was much higher than that of the porous ceramics prepared with only microfibers (0.26 MPa). Meanwhile, the backside thermal equilibrium temperature of the sample with a microfiber/nanofiber weight ratio of 1:2 at 900 °C environment was 355.8 °C, which was much lower than that of the porous ceramic prepared with only microfibers (476.5 °C). In addition, in order to investigate the temperature resistance of mullite micro/nano fiber-based porous ceramics, the sintering temperatures was increased from 1400 °C to 1500 °C. Results shows that the high-temperature thermal insulation performance of mullite micro/nano fiber-based porous ceramics with high mullite nanofiber content decays more seriously. The back-temperature test showed that the thermal equilibrium temperature of the samples with a mullite micron/nanofiber weight ratio of 1:1 in 900 °C environment increased rapidly from 386.3 °C to 454.2 °C when the sintering temperature was increased from 1400 °C to 1500 °C. The preparation of mullite micro/nanofiber-based porous ceramics provides a new strategy to improve the performance of fiber-based porous ceramics. [ABSTRACT FROM AUTHOR]

Shock/shock interactions (SSIs) often lead to high thermal loads. To understand the influences of thermochemical non-equilibrium effects on the Type III SSI, four gas models based on the assumption of thermal perfect gas (TPG), thermal equilibrium chemical non-equilibrium gas (TECNG), thermal non-equilibrium chemical frozen gas (TNCFG), and thermochemical non-equilibrium gas (TCNEG) are employed to simulate the Type III SSI at Mach 10. The intersection of incident shock and bow shock is determined by dimensionless intercept of 0.05 and 0.1. It is found that the chemical non-equilibrium effects significantly lift up the impingement position of shear layer by reducing the standoff distance of bow shock. As a result, the peaks of wall pressure and heat flux calculated by TECNG and TCNEG model are higher than TPG and TNCFG model, respectively. Type IIIa SSI occur in the flows calculated by the TECNG and TCNEG model for the case with a dimensionless intercept of 0.1. The peaks of wall pressure and heat flux calculated by TECNG model are both over four times higher than those of TPG model. The thermal non-equilibrium effects slightly increase the standoff distance of bow shock and lower the impingement position of shear layer. In addition, the thermal non-equilibrium reduces the angle to the horizontal direction of shear layer by increasing the specific heat ratio. • Type III shock/shock interaction at Mach 10 are simulated by four gas models. • The influences of non-equilibrium effects on flow fields are analyzed. • The chemical non-equilibrium effects significantly increase the peak values of heat flux and pressure. • The mechanisms of non-equilibrium effects on peak heat flux and pressure are revealed. [ABSTRACT FROM AUTHOR]

To characterize the impact of thermal nonequilibrium conditions in shock-induced combustion in high Mach number scramjet engines, a comparative numerical investigation has been performed. The combustor configuration was based on the HyShot II scramjet while the total enthalpy is 3.3 MJ/kg which resembles Mach 8 flight condition. The improved delay detached eddy simulation with Park two-temperature approach in combination with the vibration-chemical coupling model was employed in the nonequilibrium simulations. It is shown that under thermal nonequilibrium inflow conditions, noticeable stratification in the thermal state exists in the circumferential direction both in the combustor section and exhaust nozzle. In the inner core where the fuel mixes with the mainstream, flow deceleration caused by the heat release leads to a sufficient transformation of energy between the vibrational and translational-rotational modes approaching the thermal equilibrium state. However, the τ v , m i x is quite large in the supersonic mainstream, whereby the thermal nonequilibrium dominates. For the case with higher T v in the inflow, the fuel jet's penetration height is lower while the local viscosity is higher which results in poor mixing between the fuel and air stream. Nevertheless, a 400 K increase in inflow T v gives a higher effective temperature, which promotes the dissociation reactions, shortens the ignition distance and yields an 8% increase in the overall combustion efficiency. With better combustion performance, an additional 6% deceleration in the supersonic mainstream and the energy exchange rate between vibrational and translational-rotational modes becomes almost four times faster at the combustor outlet, which promotes the restoration of the thermal equilibrium state. Furthermore, under higher inflow vibrational temperature, the shock-induced combustion in supersonic crossflow becomes less stable with noticeable fluctuations in combustion heat release and local static pressure. • Combustion dynamics for the Hyshot II scramjet engine under different thermal nonequilibrium inflow conditions were investigated numerically. • Noticeable stratification in thermal state in the circumferential direction was observed when vibrational nonequilibrium effect was considered. • Increase in vibrational temperature at combustor inlet by 400 K resulted in an 8% increase in the overall combustion efficiency. • The instability of shock-induced combustion was enhanced under higher inlet vibrational temperature. [ABSTRACT FROM AUTHOR]

Recently, nanoscale thermometry has attracted extensive attention. Here, we present an innovative approach to enhance the sensitivity of upconversion nanoparticles for thermometry through near-field manipulation. This method involves a composite structure consisting of photonic crystals and upconversion nanoparticles, with the near-field of the nanoparticles manipulated by tuning the absorption of the photonic crystals. The fluorescence intensity ratio (540nm/520 nm) of 4H 11/2 and4S 3/2 states of upconversion nanoparticles doped with Er3+ ions is sensitive to temperature change and employed as a temperature indicator that satisfies Boltzmann thermal equilibrium. The composite structure exhibited a relative thermometry sensitivity of 21.9 × 10−3 K−1 at 298 K, representing a significant improvement over pure core-shell upconversion nanoparticles with a 63.43% increase in relative sensitivity and a 675% increase in absolute sensitivity. This finding demonstrates the potential of our approach for advancing nanoscale thermometry. [ABSTRACT FROM AUTHOR]

Active thin film electrochromic or thermochromic coatings have been used in smart windows. However, the current cost of active thin film windows is approximately 10 times that of passive film windows. This paper proposes an inexpensive passive thin metal film for all-season energy savings. The proposed passive thin metal film allows heat to flow preferentially in one direction. Thin metal films attached to glass indoor can absorb solar heat and the solar can radiate the heat to a room and to the glass respectively until thermal equilibrium. Because of the heated metal film against the room, as long as the temperature of the film is higher than that of the room, there is no heat flux from the room to the thin metal film which is called perfect thermal insulation. The 960m2 film was installed in an actual hotel in Japan over 10 years and contributed to reducing the energy cost of air conditioning from 54 million yen to 43 million yen, demonstrating an annual energy savings of 11 million yen (US$0.1 million). This paper briefly describes how the proposed economical passive thin metal film will provide all-season energy savings. [ABSTRACT FROM AUTHOR]

This paper explores thermal quantum memory-assisted entropic uncertainty, Bell-non-locality, and entanglement in a two-qubit Heisenberg XXX chain with x -directional Dzyaloshinskii-Moriya (DM) and Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) interactions in thermal equilibrium. We find this crucial that the initial degree of nonlocality and entanglement in the two-qubit state entirely depends upon the temperature, orientation, and strength of the DM and KSEA interaction of the magnetic field. Among many other situations, the magnetic field characterized by DM interaction with minimal temperature, exchange coupling strength, and KSEA interaction is the most reliable for generating and maintaining maximal nonlocality and entanglement while completely suppressing entropic uncertainty. On the other hand, repeated revivals and non-Markovian dynamics have been observed when the magnetic field is characterized by exchange coupling constant, DM and KSEA interaction with a higher temperature limit. Except for temperature-based magnetic fields, we show that maximal entanglement and nonlocality are generated and preserved in the two qubits with zero-order entropic uncertainty, which we believe is a better result than previous studies. [ABSTRACT FROM AUTHOR]

• An experimental methodology, Ar-diluted mixtures, was applied to measure He- and H 2 -perturbed spectroscopic parameters. • The N 2 -, He-, and H 2 -perturbed collisional broadening coefficients of the CO transition lines were measured at 1040–2980 K. • Validation experiments confirmed the accuracy of measured parameters and the availability of the proposed methodology. • The Dicke narrowing effects and the differences in the high-temperature collisional broadening coefficients were discussed. Tunable diode laser absorption spectroscopy (TDLAS) has been established as a strong technique for high-fidelity measurements at elevated temperatures. However, the accuracy of the measured data using TDLAS depends on the accuracy of the spectroscopic parameters. In this paper, the N 2 -, He-, and H 2 -perturbed collisional broadening coefficients of the CO P(0, 21), P(1, 21), and P(0, 37) lines were measured at 1040–2980 K. Ar-diluted mixtures were applied to measure these spectroscopic parameters at elevated temperatures up to 3000 K. Validation experiments highlighted that the measured temperatures and CO concentrations agreed well with the known values under thermal equilibrium and nonequilibrium conditions. Comparisons of residuals in Voigt fitting highlighted that the N 2 -perturbed Dicke narrowing effects are stronger than the He- and H 2 -perturbed phenomena. The differences among species-perturbed high-temperature collisional broadening coefficients for the three transition lines were found to be closely related to the intermolecular forces and effective collision cross-sections. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cathode dual-population MMFC model is established. • The physical fields of hydrodynamics and thermal equilibrium are coupled. • The mechanism of MMFC operation is revealed. • The concentration of bacteria and efficiency are utilized to evaluate performances. Microfluidic microbial fuel cells (MMFC) are one of the most promising power sources. However, due to the lack of clarity in the internal operating mechanism, the output performance is suboptimal. Thus, a comprehensive two-dimensional cathode dual-population model is developed to gain deeper insights into internal workings. Based on verifying the accuracy of the model, the influence of temperature, ionic strength, and spacing of electrode on the performance and microbial growth of MMFC are explored. The finding reveal a nonlinear trend in the performance of MMFC at temperatures of 293.15 K and 313.15 K. Furthermore, the impact of electrode spacing and ionic strength on the performance of MMFC is examined, thereby emphasizing the applicability in experimental research and numerical simulation. This study provided insights into the operating mechanism of dual-population microbial microfluidic fuel cells. [ABSTRACT FROM AUTHOR]

Formation of a new phase usually follows a fixed orientation relationship with matrix in metallic materials, i.e., hydrides prefer to form on the basal plane in hexagonal zirconium (Zr) under thermal equilibrium conditions. Here, we identify that hydride precipitation within α-Zr in dual-phase Zr-2.5Nb deviates from the traditional manner, being governed by β-Zr. Two types of orientation relationships between γ-ZrH and β-Zr are identified, namely Kurdjumov-Sachs and Pitsch. The habit plane of hydrides consistently aligns with {112} β. Hydrides can cross various colony boundaries but are obstructed by the β-Zr grain boundary. The high solubility and the fast diffusion rate of hydrogen inside body-centered cubic β-Zr are the origin of the unique hydride phase transformation in dual-phase Zircaloy. Our findings may provide some new understanding for solid-state phase transformation in dual-phase materials. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Adopted a novel approach for thermal stability and oxidation kinetics analyses of coal. • Dual-phase heating revealed Baseline Transition Temperature (BTT) and Ramped Terminal Temperature (RTT). • BTT of coal ranged between 110 °C and 120 °C under low-temperature oxidation. • Coal oxidation showed 5 stages thermal stability variation under dual-phase heating. • Oxygen consumption rate increases by 50–100% from isothermal to ramped heating. The low-temperature oxidation of coal remains a significant precursor of the prevailing fire hazard in the coal mining industry. This study examines the thermal stability, heat transfer dynamics, and gas emission profiles of coal samples from Indian mines to understand the factors influencing spontaneous combustion. Using a novel dual-phase heating approach with both isothermal and ramped-up heating programming, coal samples underwent controlled temperature increase, simulating natural oxidation conditions. Critical parameters such as oxygen consumption rates, emission profiles of carbon oxides, and hydrocarbon gases, as well as reaction kinetics like activation energy and pre-exponential factors, were meticulously examined. The dual-phase heating approach, focusing on the new spontaneous heating susceptibility criteria as Baseline Transition Temperature (BTT) and Ramped Terminal Temperature (RTT), provided insights into temporal and spatial temperature variations. Highest BTT at 117.8 °C and RTT up to 248.2 °C, with a peak oxygen consumption rate over 30,000 × 10-5 mol·cm−3s−1 at 250 °C, indicating high reactivity, was observed. In contrast, a lower BTT of 110 °C and an oxygen consumption rate below 20,000 × 10−5 mol·cm−3s−1 up to 140 °C, suggested better thermal stability. A five-stage analysis of thermal gradients revealed highest peak in the conduction gradient time derivative at 7 × 10-9 °C m2.min−1, indicating sensitivity towards oxidation under isothermal heating. The study identified two steady states under isothermal conditions: thermal equilibrium state at different spatial points and steady state of constant gradient. Under ramped heating, thermal stress further influenced the oxygen consumption rate and increased gas emissions, such as CO and hydrocarbons, signifying the dynamic interplay of thermal gradients and combustion risk. A significant decrease of activation energy from 59.64 to 5.90 kJ/mol demonstrated the impact of thermal stress in reducing energy barriers for oxidation, which are influenced by the moisture content, apparent porosity, temperature range, and active functional group composition of coal. These findings enhanced the understanding of interplay of coal's intrinsic properties and oxidation behaviour, which will help in developing predictive models and safety protocols to mitigate spontaneous combustion risks in coal mines, early detection of hazardous conditions, optimise storage practices, and improve overall safety management in mining operations. [ABSTRACT FROM AUTHOR]

• TiO 2 /CuInSe 2 and HF-TiO 2 /CuInSe 2 heterojunctions are recognized as p-n junction. • Built-in-potential and Mobility-transit time product improved after light soaking. • Device performance was improved by improving the absorption of TiO 2 after HF treatment. Searching of electronic system with functionality is the epitome of the material research and in this context; nanomaterials CuInSe 2 and TiO 2 are the promising stars whose possible applications in electronic devices are just endless. However, the fabrication of junction based device using these two materials is most tantalizing prospect in material science is still at its rudimentary stage. In this letter, we report our recognition of current rectification behavior of CuInSe 2 /TiO 2 heterojunction, identical to the I-V characteristics of p-n junction diode and the impact of white light on it. The HOMO-LUMO band positions of hydrothermally derived CuInSe 2 and TiO 2 nanomaterials indicate that in thermal equilibrium a built-in-potential must arise across the junction. The current-rectification ratio of the configuration Al/CuInSe 2 /TiO 2 /ITO is improved from 560 to 627 at voltage ±2 V on white light illumination and this kind of behavior is certainly offering us an unprecedented way to realize the CuInSe 2 /TiO 2 hetero-junction as photo-sensing p-n diode. The device performance is improved further by replacing TiO 2 with HF treated TiO 2. [ABSTRACT FROM AUTHOR]

Complex concentrated alloys (CCAs) are promising candidates for applications in extreme conditions, such as irradiation where interstitial mediated diffusion is important. In CCAs with N principal elements, N (N + 1) 2 types of dumbbell interstitials exist. Currently, there is no way to predict the thermal partition (fractional concentration at equilibrium) and the dynamic partition (fractional time an interstitial spends during diffusion) of each type of dumbbell interstitial. To mitigate this issue, this work proposes a theoretical model for computing the equilibrium concentrations and thermal partition of dumbbell interstitials in CCAs and validates the model using grand canonical Monte Carlo simulations. Lattice kinetic Monte Carlo simulations show that the thermal partition is equivalent to the dynamic partition, and both are governed by composition and formation energies of dumbbells. The model proposed provides a foundation for understanding radiation enhanced diffusion and induced segregation in CCAs under irradiation. [Display omitted] [ABSTRACT FROM AUTHOR]

The optimization of joint microstructure plays a critical role in assessing joint performance under high heat flux (HHF) conditions, as it dictates the final properties of the joint. This study investigates tungsten-EUROFER joints brazed using a copper interlayer as filler material under optimized brazing cycle conditions (1110 °C, 3 min), and subjected to simulated high heat fluxes exposing the plasma facing material, tungsten in this case, to a heating source (accelerated electron bean), while the joint is refrigerated through the EUROFER side. This experiment aims to mimic the heat fluxes and cooling conditions experienced in a fusion reactor environment. An optimized microstructure of the braze joint, designed to mitigate the formation of intermetallic compounds and undesirable phases, was implemented to enhance joint responses under high heat flux loads. The joints were subjected to 100 and 1000 heating-cooling cycles of 10/12 s. The target during heating is to reach the thermal equilibrium. Three different tungsten surface temperature were evaluated (600 °C, 700 °C and 800 °C) in different sample batches while cooling on the EUROFER side, removing the heat source during the cooling stage. Some overheating events, associated with crack propagation through the EUROFER-braze interface identified during the subsequent postmortem analysis by SEM, were detected during the application of some conditions of the test. The microstructure examination also reported a modification of the failure mechanism of the joint comparing with the previous studies and literature. This modification is associated with the optimized microstructure resulting in improved response to high heat flux loads. Interestingly, the shear strength increased to an average of 95.0 MPa after HHF testing, compared to 40.2 MPa obtained in similar joints with different microstructures. • The optimized microstructure in W-EUROFER brazed joints has modified the crack propagation mechanism experimented. • The crack propagation follows the EUROFER-braze interface instead of the W-braze one. • The shear strength of the joints after the tests is roughly doubled compared to the 50 MPa obtained for the non-optimized joint tested previously. [ABSTRACT FROM AUTHOR]

δ-Valerolactone (DVL) is a five-carbon (C5) cyclic ester that can undergo ring-opening polymerization to yield high-performance, biocompatible polyesters. But current market prices of C5 chemicals like DVL are very high due to poor availability of C5 feedstock in petroleum. Herein, we demonstrate a novel route to DVL synthesis via dehydrogenation of biomass-derived 2-hydroxytetrahydropyran (HTHP) over Cu/SiO 2 without the use of toxic reagents. Since HTHP exists in thermal equilibrium with 3,4-dihydropyran (DHP) via dehydration, and with 2,2'-oxybis(tetrahydropyran) and 5-(tetrahydropyran-2-yloxy)pentanal via acetalization, we have also determined the thermochemistry (ΔH rxn and ΔG rxn) of each competing reaction using density functional theory (DFT) calculations at the M06–2X/cc-pVTZ level. Lastly, by developing a kinetic model of all 8 reactions involved, we have achieved 84 % selectivity to DVL at 150°C in a packed bed reactor for over 72 hours of time on stream. [Display omitted] • DVL can be produced through selective catalytic dehydrogenation of HTHP. • HTHP undergoes competitive thermal driven dehydration and acetalization reactions. • Cu supported catalysts are the most efficient for HTHP conversion into DVL. • Reaction conditions for DVL production are optimized through kinetic modeling. • Maximum 84 % selectivity to DVL is achieved in flow reactors at 150°C for 72 h. [ABSTRACT FROM AUTHOR]

• Heat flow and subsurface temperature were modeled in the williston Basin, USA. • High heat flow was identified near poplar dome, Montana, and trending north-south in north dakota. • Moderate temperature (90 °C to 150 °C) and permeability likely exist in the sedimentary section. As part of U.S. Geological Survey's (USGS) efforts to identify and assess geothermal energy resources of the US, a three-dimensional (3D) geologic and thermal model has been constructed for the Williston Basin, USA. The geologic model consists of all sedimentary units above the Proterozoic and Archean crystalline rock (called basement herein), with a total sedimentary thickness of up to 5 km near the basin center. Twenty-nine geologic units were mapped from interpreted formation tops from 16,465 wells. A 3D temperature model was constructed to a depth of 7 km by constructing a 3D heat flow model for the sedimentary units, followed by estimating underlying temperature using a one-dimensional (1D) analytic solution for heat flow within the underlying crystalline basement. Using the sedimentary basin model, heat flow was simulated in 3D and was calibrated using three temperature datasets: 1) 24 high-confidence static temperature logs (equilibrium thermal profiles), 2) more than15,000 drill stem test (DST) measurements from >7,000 wells, and 3) more than 45,000 bottomhole temperature (BHT) measurements from >14,000 wells. The DST and BHT datasets provide broad spatial coverage, but are lower confidence, primarily because measurements were made prior to attaining thermal equilibrium. DST and BHT measurements were binned regionally to develop representative thermal profiles that generally agree with these lower quality data (hereafter called pseudowell temperature profiles). Layer properties (primarily thermal conductivity and compaction curves) were set to best estimate values, then the heat flow model was calibrated to fit pseudowell and static temperature logs primarily by adjusting basal heat flow to approximate the overall temperature profile. Minor adjustments to thermal conductivity allowed adjusting changes in slope at lithologic contacts. Resulting maps include 3D temperature and basal (bottom of sedimentary units) heat flow estimates, which are used as input for the temperature model of the basement. The crystalline basement temperature model uses an analytic 1D solution to the heat flow equation that requires estimates of heat flow and temperature at the upper boundary (i.e., the sediment/basement contact), radiogenic heat production within the crystalline basement, and reference thermal conductivity (i.e., uncorrected for temperature). Two regions of high heat flow are identified: 1) in western North Dakota along the North American Central Plains Conductivity Anomaly and 2) in eastern Montana near the Poplar dome. Within the sedimentary column in the center of the basin of the basin, an area of approximately 100,000 km2 is predicted to have moderate- to high-temperature geothermal resources (>90 °C) under the thickest sequences of sediments. Where thick insulation and high heat flow coincide, electric-grade resources can be less than 4 km deep. Assuming a maximum feasible drilling depth of 7 km, temperatures are predicted to be as high as 175 °C. The geologic model may be used to identify strata at sufficient temperatures that may have natural permeability or that may have conditions that favor development of enhanced/engineered geothermal systems resources. [ABSTRACT FROM AUTHOR]

In this review, we present the key aspects of modern thermal perturbation theory based on the hard thermal loop (HTL) approximation, including its theoretical foundations and applications within quantum electrodynamics (QED) and quantum chromodynamics (QCD) plasmas. To maintain conciseness, we focus on scenarios in thermal equilibrium, examining a variety of physical quantities and settings. Specifically, we explore both bulk thermodynamic properties and real-time observables in high-temperature domains relevant to heavy-ion physics. [ABSTRACT FROM AUTHOR]

The Baja California peninsula forms the western margin of the Gulf of California (GC) rift system, which is an active tectonic setting manifested by seismicity and numerous geothermal sites. The present study examines the geochemistry of thermal fluids (major ions and gas species, δ18O-δD, δ13C, 3He/4He) from the southern tip of the peninsula (Los Cabos Block, LCB). Sampling was mostly focused on the coastal thermal manifestations in the towns of Buenavista and El Sargento, but other sites further inland are also included for broadening the scope of the study. The main objectives include: (i) characterize water-rock interactions and other processes controlling the fluid composition, (ii) constrain solute geothermometry estimates through multi-step geochemical modeling, and (iii) discuss the fluid origins in terms of tectonics and regional shear-wave velocity anomalies in the upper lithosphere. The geothermal systems in the area have a tectonic origin and result from fluid circulation along regional faults that penetrate the upper crust through the granitic basement. Mixing between the thermal fluids and seawater at the coast is clearly illustrated through major ions and δ18O-δD relationships. Reconstruction of the pre-mixing chemical compositions indicates a low-salinity fluid at Buenavista (Cl = 104–109 mg L−1) and a saline fluid at El Sargento (Cl = 7169 mg L−1). The geochemical modeling allows us to validate these endmember compositions and to address a common issue when using solute geothermometry, which is the uncertainty on the state of equilibrium of the thermal fluid with respect to wall-rock minerals. The corresponding results reveal contrasting thermal regimes at depths (Buenavista: 101–122 °C, El Sargento: 212–220 °C), likely associated with differences in geothermal gradient and fluid circulation depth. Our gas samples have among the lowest He isotopic ratios (0.07–0.95 R a) in the Baja California peninsula, indicating that the origin of helium is mainly crustal. Shear wave tomography demonstrates that the study area is associated with two low velocity regions, one in the crust and the other one in the upper mantle. Our results favor the hypothesis that the heating of fluids is produced by lower-crustal flow driven by strong topographic gradients along the rifted margin. This study provides new insights into the origin of the thermal anomalies in the LCB and the adjacent GC rift system. • Thermalism in the Los Cabos Block results from fluid circulation along regional faults. • Geochemical modeling is key to validate deep fluid compositions and temperatures. • The lack of mantle He signature may reflect lower-crustal flow driven by topography. [ABSTRACT FROM AUTHOR]

• Direct numerical simulations of high-enthalpy supersonic turbulent channel flows are performed. • The influence of wall temperature on the chemical activity and turbulent statistics are investigated. • The decomposition formulas of heat flux and skin friction are derived, and their characteristics are analyzed. Direct numerical simulations of temporally evolving high-enthalpy supersonic turbulent channel flows are performed at a Mach number of 3.0 and Reynolds number of 4880. The high-enthalpy air is assumed to behave as a chemical and thermal equilibrium of five-species mixture. The wall temperatures in the range of 1733.2 K to 4100.0 K to study the influence of wall temperature on the chemical activity, turbulent statistics and aerodynamic characteristics. The results show that the chemical activity is remarkable because the air is relatively sufficient dissociated. When the wall temperature higher than 2300 K, an extreme value can be observed in the distributions of mean and fluctuating mass fraction of atomic nitrogen close to the wall. Many of the influence of wall temperature on the turbulent statistics which hold for low-enthalpy conditions also hold for high-enthalpy conditions, including mean and fluctuating velocity, recovery enthalpy, and strong Reynolds analogy. As the wall temperature increases, the turbulent momentum flux and turbulent heat flux decrease, the turbulent mass flux mainly depends on species mass fractions fluctuations. The integral formulas of decomposing the aerodynamic characteristics are proposed, and the predicted heat flux and skin friction are all in good agreement with those direct estimation. The wall temperature does not change the primarily contributions of aerodynamic characteristics. Although the turbulent heat flux term is approximately 6%, its part of turbulent transport of enthalpy significantly increases with increasing wall temperature. The turbulent Schmidt number is insensitive to wall temperature. [ABSTRACT FROM AUTHOR]

Dissipative particle dynamics with energy conservation is a mesoscopic numerical method used to simulate heat transfer in complex fluids. However, while this method can determine the fluid temperature, it cannot directly calculate the heat transfer rate from a solid wall to the fluid. This study introduces a novel boundary treatment that calculates the heat transfer rate from the solid wall to the particle based on the increment in the thermal energy of the particles. To validate this approach, we simulated stationary water in a channel using in-house code to estimate the thermal conductivity of water. The dissipative particle dynamics method, enhanced with the proposed boundary treatment, accurately predicted the thermal conductivity of water within the temperature range of 280 to 360 K, with errors of less than ±2.5 %. Additionally, thermal conductivity in equilibrium was obtained using the Green-Kubo formula and compared with the results from the dissipative particle dynamics method. The thermal conductivity obtained via the Green-Kubo formula exhibited significant fluctuations. • The alternative expression for the Boltzmann temperature is introduced into DPDe. • Non-Dimensionalization based on the coarse-graining parameter is introduced into DPDe. • A novel boundary treatment where DPD particles directly collide with walls is proposed. • The heat transfer rate from walls can be predicted by the proposed boundary treatment. • The thermal conductivity of water in the range of 280 to 360 K can be predicted within error of ±2.5 %. [ABSTRACT FROM AUTHOR]

In order to improve the cooling performance and drag reduction performance of active thermal protection, this paper proposes to replace the single transpiration cooling with the coupling of directional transpiration cooling and regenerative cooling. The thermal protection and drag reduction characteristics of composite cooling with different directional angles are numerically investigated based on a thermal equilibrium model, utilizing endothermic hydrocarbon fuel as the coolant. The numerical results demonstrate that directional angle hinders the easy outflow of coolant at the starting position of transpiration, leading to localized high temperature phenomena. However, with an increasing directional angle, the enhanced high temperature effect promotes an increase in hydrocarbon fuel cracking degree while weakening the occurrence of local high temperature phenomena. Moreover, the directional angle enhances the stability of coolant adherent flow at the outlet of the porous medium, thereby effectively reducing resistance to high enthalpy airflow through directional transpiration cooling. In summary, the thermal protection performance/drag reduction performance coupling matching characteristics of directional transpiration cooling with the directional angle of 45° are the best in the research range. • A composite cooling model of directional transpiration cooling and regenerative cooling is established. • Directional transpiration cooling causes local high temperature at the starting transpiration position. • Directional transpiration cooling effectively reduces the resistance of coolant to high enthalpy airflow. • The thermal protection and drag reduction performance achieve the best coupling when the directional angle is 45°. [ABSTRACT FROM AUTHOR]

• Metal foam is employed for partial filling to enhance the efficiency of a PCM-based heat sink. • Optimal partial filling ratio is determined to be 2/3 and is found to be more cost-effective than fully filling case. • The filling ratio of 2/3 offers a notable gain of 6.19 % in latent heat capacity. • A reduction of 33.33 % in material cost and overall heat sink weight is proved. Electronics often experience overheating, which occurs when insufficient or improper cooling causes temperatures to rise quickly, potentially leading to component failure. Recently, a passive technique utilizing phase change material (PCM)-based heat sinks is suitable for modern electronic cooling. However, due to its low thermal conductivity, Aluminum (Al) foam as a thermal conductivity enhancer (TCE) is used. In this study, a partial filling approach is employed, involving a heat sink designed to cool a protruding electronic component (EC) attached to a metal fin. The enthalpy-porosity method and the thermal equilibrium model are applied. Results show that the efficiency of the heat sink is improved by increasing the filling ratio of the Al foam, thereby reducing the EC temperature by 15.85 °C, shortness the melting time by more than 1000 s, and the overall effective conductivity enhanced by 25 times compared to the case without Al foam. In addition, the optimal partial filling ratio is determined to be 2/3, due to the considerable savings of 33.33 % in material cost and overall heat sink weight. The findings suggest that partial filling is a strategy that can be employed to achieve a more comprehensive performance in thermal management using PCM-based heat sinks. [ABSTRACT FROM AUTHOR]

• Cycle for the reciprocating solid-state magnetic refrigeration system is proposed and experimental simulated. • The system uses mechanical thermal switch. • GdNi 2 alloy is used as a working body. The aim of this work is to implement a real single-stage cryogenic cooling cycle with help of experimental data to assess the parameters of energy efficiency. For this purpose, the process of heat transfer from the working body to the heat receiver is considered. The working body is a magnetocaloric material GdNi 2 with mass 7.68 g, and the heat sink is a copper disk with mass 5.35 g. Heat exchange between the working body and the heat sink occurred through mechanical contact. Data on changes in the temperature of the heat sink and working body in conditions when a mechanical thermal switch is «on» were obtained in result of direct measurements by an experimental method. Based on the obtained experimental data, the Brayton refrigeration cycle was implemented and the cooling capacity was calculated for various initial temperature differences of the working body and the heat sink T span ≈ 1 - 3 K, while they were exposed to an external magnetic field of 5 Tesla in the temperature range 74 - 78 K. It is shown that the time to achieve thermal equilibrium of the contact pair of a mechanical thermal switch is about 80 s at the initial temperature of the heat sink 75 K. This work provides a comparison with other works and analogues. The value of the magnetocaloric effect for the GdNi 2 working body was experimentally determined in magnetic fields of 3, 5 and 10 T and a temperature range of 48–105 K. The maximum value of the magnetocaloric effect is 2.87 K at an initial temperature T = 75 K in a magnetic field of 5 T. Based on experimental data, the thermal contact conductance of the GdNi 2 - Copper contact pair was calculated under conditions of unsteady heat flow in the temperature range of 60 - 100 K. The thermal contact conductance of the contact at T = 75 K was 3970 W/(m2K). [ABSTRACT FROM AUTHOR]

Temperature fluctuations impact battery performance, safety, and health. Industry-standard cell-level models of these phenomena ignore thermal gradients within the electrodes' active material, i.e., assume the latter to be in "thermal equilibrium". We present a "non-equilibrium" thermal model that explicitly accounts for spatial variability of temperature with the active material (and the carbon-binder domain). We investigate the conditions, expressed in terms of the heat-generation rate and the thermal properties of a cell's liquid (electrolyte) and solid (active material and CBD) phases, under which the thermal equilibrium assumption breaks down and our model should be used instead. The differences between these two thermal models are investigated further by coupling them with an industry-standard electrochemical model. The resulting thermal–electrochemical model demonstrates the importance of thermal gradients within the active material at high C-rates (discharge current densities) and for large grain sizes. Under these conditions, the equilibrium assumption underestimates internal temperature by as much as 50%. These two thermal models are then applied to a commercial NMC battery with multiple units. Our non-equilibrium model predicts the battery surface temperature that is in good agreement with measurements, while the equilibrium model underestimates the observed temperature. [Display omitted] • Our non-equilibrium model accounts for temperature variability in active material. • Thermal gradients in solid phase are important at high C-rates for large grains. • The equilibrium assumption underestimates internal temperature by up to 50%. [ABSTRACT FROM AUTHOR]

Understanding heat transfer processes in fractured porous media is critical for characterizing thermal behaviors and improving the operation efficiency of geothermal energy. The field observations have shown that many fractures are filled with sediment infilling rather than being fully open, but heat transfer in such a filled fracture-rock matrix system has received less attention to date. Since multiple domains are involved in such a system and the fracture is highly permeable even with sediment infilling, local thermal equilibrium may not be reached instantaneously. In this study, a fully coupled analytical model is proposed and developed to investigate the role of transient local heat transfer in the filled fracture-rock matrix system and analyze the spatiotemporal thermal distributions in each domain. The results indicate that multiple thermal properties of the rock matrix, such as average volumetric thermal capacity and thermal conductivity, have significant impacts on the spatiotemporal thermal distribution in the fracture. The temperatures of the pore water and sediment infilling in the fracture are sensitive to flow velocity, thermal conductivity of the rock matrix, and volumetric thermal capacities of the fluid and rock matrix. The thermal transfer coefficient has moderate interaction effects with other parameters according to the sensitivity analysis. [ABSTRACT FROM AUTHOR]

• Novel integration of MWIR and LWIR imaging for biofuels combustion study. • Investigates complex effects of airflow on biofuels combustion dynamics. • Insights into volatile-char combustion transitions affected by airflow variations. • Inverse relationship between total combustion rate and combustion efficiency. • Novel use of spectral radiance ratios for gas analysis. Biomass charcoal combustion is a complex process, significantly influenced by various operating parameters. Among these parameters, air supply emerges as a critical factor affecting combustion efficiency, gas emissions, and thermal dynamics. In this study, we explored these complex interdependencies using a novel combination of mid-wavelength infrared (MWIR) hyperspectral imaging and long-wavelength infrared (LWIR) thermal imaging, under different airflow rates. Our findings demonstrated that while increased airflow accelerated the overall combustion rate, it simultaneously decreased combustion efficiency. Specifically, the thermal profiles showed an increased surface temperature at a low flowrate (0.5 L/min) while decreasing in temperature with higher flowrates. The decreased system temperature led to a lower combustion efficiency because of the reduced conversion rate from combustible gases (CH 4 and CO) into CO 2 and H 2 O. Additionally, the results also demonstrated that cooling effects of the high flowrates primarily impeded the solid-phase combustion stage. This is further corroborated by the temporal and spatial variation in the emissions of key gas species (H 2 O vapor, CH 4 , CO, and CO 2) observed through hyperspectral imaging. The emission evolution of these gases displayed the different stages of the gas-phase and solid-phase combustion. The spatial distribution of the trace gases showed a decreased distribution radius due to the enhanced diffusion to the fuel surface when the airflow increases, aligning well with the two-film model established in the literature. Furthermore, we utilised spectral radiance ratios (CO/CO 2 , CH 4 /CO 2 , H 2 O/CO 2) to gain additional insights into the combustion dynamics. These ratios evidenced the decrease in combustion efficiency at high airflow rates. Finally, the increased H 2 O/CO 2 ratio further demonstrated the impeded char combustion and a shift towards pyrolysis at higher airflow rates because of the decreased thermal equilibrium of the system. The findings from this study provide critical insights into the dynamics of biomass charcoal combustion and illuminates the path for optimising energy efficiency and assessing the environmental implications from burning biomass fuels. [ABSTRACT FROM AUTHOR]

• Capacitance two-phase measurement using cross-correlation and normalization. • Average error < ±2% from 0 to 100 % volume fraction with cryogenic hydrogen. • ½" tube with flow rates from 0.0058 to 0.026 kg/s and velocity from 0 to 6.65 m/s. • Transient and steady state flows are measured. Mass flow rate is a critical measurement parameter when designing cryogenic hydrogen fluid systems. It is important in custody transfer applications for calculating financial obligations, fundamental fluid property research/modeling, and fluid system design applications to optimize chill down performance, maintain thermal equilibriums, and provide feedback control for pumps and valves. However, due to the large temperature differential between cryogenic fluids and the environment, there is often multiphase flow during system chilldown and steady state operation. Current available cryogenic flow measurement techniques are not equipped to deal with the complex multiphase flow inherent in cryogenic fluid systems, resulting in significant measurement errors. This mass flow measurement inaccuracy can cause financial loss, system instability, and even component failure, resulting in a strong market demand for a multiphase cryogenic mass flow meter to optimize and control sophisticated and costly cryogenic systems. This paper presents a solution in the form of a novel capacitance-based technique for measuring the multiphase mass flow rate of cryogenic hydrogen in a terrestrial environment. The device was calibrated and tested on a ½" tube multiphase hydrogen flow loop at a cryogenic hydrogen test facility. An error of ± 2 % full scale was achieved across a range of flow conditions, including transient and steady states. [ABSTRACT FROM AUTHOR]

In this work, the spatial distribution and spectral characteristics of the chemiluminescence of chemically excited species, OH ∗ and CH ∗ , are experimentally and numerically studied by using a stationary premixed methane–air flame stabilized on the surface of a flat porous burner for various equivalence ratio and normal pressure. Numerical simulations are carried out using detailed reaction mechanisms, and the experimental study includes high-resolution spatial and spectral optical measurements. Despite the data reported in the literature, it is found that (i) the rotational degrees of freedom of OH ∗ and CH ∗ are not in thermal equilibrium with the surrounding gas and therefore cannot be used to measure flame temperature; (ii) there is no direct correlation between the heat release rate and the distribution of OH ∗ and CH ∗ ; (iii) the detailed reaction mechanisms not only quantitatively, and also qualitatively differ in description of the OH ∗ and CH ∗ concentrations. Since the chemically excited species are well localized in a direction normal to the flame surface, they are demonstrated to be a very accurate markers of flame location. The shape of the combustion front can be reconstructed and resolved up to the accuracy of tens of microns, which is very important for estimation of blow-off critical parameters and measurement of the laminar burning velocity. Novelty and significance statement Currently, there is a growing interest in the development of sensors for combustion control systems, including active control and suppression of instabilities, in combustion chambers of various devices and engines based on chemiluminescence of excited reaction species. The possibility of non-invasive determination of parameters such as flame temperature, stoichiometry, heat release rate location, etc. using this technique is discussed. We have found that most of these parameters cannot be estimated either due to fundamental limitations or insufficient knowledge of the reaction kinetics involved in the production of these species. Nevertheless, since OH* and CH* are well localized in the direction normal to the flame surface, they can be used as very accurate markers of flame shape and position, allowing us to reconstruct the flame surface to within tens of microns resolution, which is very important for estimating blow-off critical parameters and measuring laminar burning velocity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Post-mineralization faulting exposed commercial ore bodies near the surface at Zhunuo. • The erosion amount in the primary mining area of the Zhunuo deposit is no less than 1.8 km. • There may still be concealed ore bodies in the deep part of eastern Zhunuo, under the control of post-ore faulting. The Zhunuo deposit is the westernmost large porphyry copper deposit in the Gangdese porphyry copper belt. Petrological, geochemical, and thermochronological studies have reported its genesis, magmatic-hydrothermal evolution, and the effects of post-mineralization faulting. However, as exploration deepens, previous understandings of ore preservation have not been fully confirmed. We present new apatite (U-Th)/He (AHe) analyses targeting the post-mineralization Nongsang fault to assess the impact of fault activity on the ore body and explore potential directions for future exploration. AHe ages obtained from Miocene samples in this study range from 18.7 ± 1.1 Ma to 7.7 ± 0.4 Ma, and the associated experimental data were used for thermal history reconstruction. Two-stage cooling processes of the Zhunuo deposit have been identified: an initial rapid cooling due to heat dissipation from the magma reaching thermal equilibrium with the surrounding rock, followed by a slower cooling period influenced by tectonic movements and exhumation. The Nongsang fault has been confirmed as a high-angle normal fault, with a dip direction of 74° and a dip angle of 85°. Constraints from the age-elevation relationship, combined with the elevation difference between the matched ore layers on both sides of the fault, revealed a fault displacement of at least 300 m. The primary mining area in the western footwall of the fault has experienced more intense erosion of no less than 1.8 km, exposing numerous ore-related intrusions at the surface. In contrast, the eastern hanging wall has undergone relatively less exhumation, retaining a voluminous Eocene quartz porphyry cap and possibly containing undiscovered, undisturbed ore bodies. Tectonic activity plays a crucial role in the exhumation and preservation of the Zhunuo deposit. It is suggested that in the broad volcanic-covered areas west of the Zhunuo deposit, large-scale porphyry deposits with significant potential may still be buried underground, based on comparisons of tectonic control and post-mineralization preservation of porphyry deposits at different locations in the Gangdese porphyry copper belt. [ABSTRACT FROM AUTHOR]

The thermal management system's architecture is crucial for lithium batteries' efficiency and financial viability, predominantly influencing their security and longevity. We conceptualized a double-layer enhanced LCP, meticulously crafted to augment the heat dissipation capabilities of the battery assembly. This novel design targets the reduction of peak temperatures and pressure drops, fostering an even internal temperature profile. Comprehensively evaluate the performance of different settings of the coolant cooling system, and the monitoring points are strategically set in horizontal and vertical directions. Analyzing the data, it becomes evident that the system's vertical orientation significantly affects the battery module's peak temperature and temperature variation. Furthermore, extensive investigations were conducted on the impact of layout, coolant flow rate, and inlet temperature on thermal dissipation. Our findings indicate that the double-layer enhanced liquid cooling plates outperform conventional designs. There is a substantial 2.41 % decrease in the peak battery module temperature and an 80.6 % reduction in voltage decline. Operating at a flow rate of 10 g per second and an entry temperature of 25 °C, our liquid cooling system demonstrates superior cooling efficiency with minimal power consumption. It proficiently restrains the maximum battery module temperature below 30.43 °C and restricts temperature variance to merely 3.48 °C. The suggested approach in this research contributes to improved thermal equilibrium, diminishes temperature disparities and pressure concerns, thereby fostering the technological advancement of electric vehicle's liquid cooling systems. [ABSTRACT FROM AUTHOR]

• The analysis of a buoyancy-driven nano-suspension subject to interstitial solid/nanofluid heat transfer coefficient is carried out. • The studied domain is a cross-shaped enclosure embodying two hot and cold rings. • The impacts of local thermal non-equilibrium (LTNE) and Forchheimer-Brinkman-extended Darcy model are considered. • The governing equations for the nanofluid, solid phases, and entropy generation in their dimensionless form, are solved using the finite element method. Because of the prominent temperature discrepancy between fluid and solid in porous material, local thermal equilibrium (LTE) is not suitable in case of high-conductivity foams and electronic equipment. In view of above situation, Darcy-Brinkman-Forchheimer model subject to local thermal non-equilibrium (LTNE) is implemented. LTNE technique finds real world applications include groundwater pollution, geothermal extraction, microwave heating, industrial separation process, and transpiration cooling featuring with porous structure. The present study aims at the investigation of the entropy and hydrothermal characteristics of buoyancy-driven TiO 2 -H 2 O nanofluid inside a cross-shaped domain embodying two hot and cold rings influenced by LTNE. Finite element method (FEM) has been considered to solve the dimensionless form of governing equations. Amplification of interstitial solid/nanofluid heat transfer coefficient accounts for the intensification of streamlines, velocities, and diminution of isothermal lines in both nanofluid and solid matrix phases under the influence of LTNE. Strengthening of medium porosity whittles down entropy due to thermal effects in both nanofluid and solid phases, and that ameliorates entropy due to fluid friction and porous medium irreversibilities. Local and average Nusselt numbers in nanofluid phase reduce by 29.31 %, 20.72 %, 17.16 %, and 14.78 % while that in solid phase decays by 13.18 %, 7.63 %, 4.9 %, and 2.8 % for rise in εfrom 0.1 to 0.3, 0.3 to 0.5, 0.5 to 0.7, and 0.7 to 0.9, respectively. Introduction of Darcy-Brinkman-Forchheimer model subject to LTNE yielded better results in hydrothermal behavior of TiO 2 -H 2 O nanofluid inside a cross-shaped domain emplacing two hot and cold rings than earlier published results. [Display omitted] [ABSTRACT FROM AUTHOR]

The prime motive of this disquisition is to scrutinize simultaneous aspects of external forcing mechanism and internal volumetric forces on non-Newtonian liquid filled in square enclosure. Inertially driven upper lid is assumed by providing constant magnitude of slip velocity whereas thermal equilibrium is disturbed by assuming uniform temperature at lower boundary and by keeping rest of walls as cold. To enhance thermal diffusion transport with in the flow domain cold as well as adiabatic temperature situation is provided. In view of velocity constraints all the extremities at no-slip except the upper wall which is moving with U Lid . Formulation is attained in dimensional form initially and afterwards variables are used to convert constructed differential system into dimensionless representation. A numerical solution of leading formulation is sought through Galerkin finite element discretization. Momentum and temperature equations are interpolated by quadratic polynomials whereas pressure distribution is approximated by linear interpolating function. Domain discretized version is evaluated in view of triangular and rectangular elements. Newton's scheme is employed to resolve the non-linearly discretized system and a matrix factorization based non-linear solver renowned as PARADISO is used. Validation of results is ascertained by forming agreement with existing studies. In addition, grid independence test is also performed to show credibility of performed computations. Stream lines and isothermal contours patterns are portrayed to evaluate variation in flow distributions. Kinetic energy and local heat flux for uniform and non-uniform heating situations are also divulged in graphical and tabular formats. Increase in Reynold number produces decrease in kinetic energy of fluid. Enhancement in Grashof number causes enrichment of thermal buoyancy forces due to which Nusselt number uplifts. Clock wise rotations increase against upsurge in magnitude of Reynold number which is evidenced form stream lines. Squeezing of secondary vortex against Prandtl number arises due to dominance of viscous forces. [ABSTRACT FROM AUTHOR]

• Microscopic model for coupling mass transfer and heat transfer. • The scale effect on microscopic mass and heat transfer mechanisms is significant. • The limitations of the continuous medium model become apparent as scale expands. The presence of a tight matrix and various fractures creates multiple scales of environments, complicating mass and heat transfer within porous media. This study presents a microscopic model that describes the coupling of mass and heat transfer mechanisms under local thermal equilibrium. The model incorporates mass transfer driven by differential pressure and diffusion, as well as heat conduction. Numerical solutions using the finite element method investigate these mechanisms across nanopore-throat, micropore-throat, and millimeter-fracture scales. Key findings indicate that at the nanopore-throat scale, mass transfer lags significantly behind heat transfer due to concentration gradients, while heat transfer is primarily facilitated by conduction. At the micropore-throat scale, heat transfer slightly lags behind mass transfer, influenced mainly by pressure differentials. At the millimeter-fracture scale, the rock cools more slowly than the fluid, with mass transfer driven by pressure differences and notable convective heat transfer. Comparisons between microscopic and macroscopic models highlight the importance of scale on transport processes. This research provides a theoretical foundation for microscale numerical simulations. [ABSTRACT FROM AUTHOR]

• Topology optimization of TPMS heat sink based on effective model is proposed. • The effective models adopt non-Darcy and local thermal equilibrium models. • The relationships between the effective parameters and density are established. • The heat transfer and flow performances of optimized TMPS heat sink are improved. To improve the performance of triply periodic minimal surfaces (TPMS) forced convection heat sinks, this study proposes an I-graph-wrapped package (IWP) TPMS topology optimization method based on a porous media effective model. The effective model establishes relationships between the porosity and effective parameters, simplifying flow and heat transfer calculations in the IWP-TPMS. The flow effective model adopts a non-Darcy model with key parameters, such as the Forchheimer coefficient and permeability, determined via the representative element volume and the Ergun equation. The thermal effective model is based on local thermal equilibrium, and the effective thermal conductivity is characterized by a series-parallel hybrid model. Topology optimization employs a density-based approach, treating IWP-TPMS structures with varying porosities as distinct materials, aiming to minimize the reciprocal of the performance evaluation criterion (PEC) for optimal overall performance. The proposed effective model is validated through case studies. The results show that the optimized IWP-TPMS reduces the peak temperature and pressure drop, with case 1 achieving reductions of 3.20% and 12.56%, respectively, and case 2 achieving reductions of 11.66% and 39.13%. These results highlight the effectiveness of combining a porous media effective model with topology optimization for optimization design of TPMS heat sinks. [ABSTRACT FROM AUTHOR]

• A macro scale heat pipe calculation model is established and validated. • The two-phase flow and heat transfer in the porous wick are calculated by the two-phase mixture model (TPMM) of porous medium. • Compared with the single-phase model, the increase of kinematic viscosity in the two-phase region greatly increases the liquid pressure drop. • Capillary pressure may be an obstacle to liquid backflow when axial volume force is applied. This paper proposes a new method for calculating heat pipes, in which the porous wick inside the heat pipe is described by the two-phase mixture model (TPMM) of porous medium based on the modified temperature model that adopts the local thermal equilibrium assumption. The capillary pressure inside the wick is characterized by the Leverett capillary pressure model. This model can calculate the two-phase flow within the heat pipe wick at the macroscopic scale level and achieves a full-field coupled solution for the wick-vapor-wall flow and heat transfer process by a specific coupling method. Finally, the paper conducts a coupled heat transfer calculation for a heat pipe using potassium as the working fluid, verifies the correctness of the model and solution method by comparing it with the experimental results, and studies the flow and phase transition patterns of the heat pipe under multiple heating and different overload conditions. Compared with the traditional single-phase porous medium model of heat pipes, the new model can consider phase transition within the porous wick. While compared with pore-scale methods, the macroscopic research scale of the new model can reduce the computational resources required. [ABSTRACT FROM AUTHOR]

We study the effect of interaction between bath spins on central spin dynamics. For this end, we consider various types of interactions among the bath fluctuators. We give an analytical relation for the dephasing dynamics of a central spin homogeneously interacting with a bath of classically interacting spins in thermal equilibrium. The obtained exact relation for the central spin dynamics depends on the average of the number of bath spins N in the canonical ensemble. We find the relation of dephasing time with bath's temperature and strength of interaction between bath spins. We show that if the classically interacting bath is large enough, off-diagonal coherence will decay into Gaussian form. This Gaussian decay is valid for temperatures higher than critical temperature. Moreover, we analytically prove the equivalence of dephasing dynamics for central spin models with classical Ising spin bath and quantum flip-flop spin bath interactions. Therefore, the dephasing dynamics for central spin models with quantum spin bath interactions can be reproduced with much less expensive classical spin bath interaction model instead. Our results can be applied in a number of quantum systems used in quantum sensing such as color centers in solids or quantum dots manuscript. • We give an analytical relation for the dephasing dynamics of a central spin. • Central spin dynamics depends on the average of the number of bath spins. • For a large bath, off-diagonal coherences decay into Gaussian form with a time scale determined by the variance of bath spins magnetization. [ABSTRACT FROM AUTHOR]

In this letter, we demonstrate energy transfers and thermalization in an isolated ensemble of realistic gas particles. We perform a grid-free classical molecular dynamics simulation of two-dimensional Lenard-Jones gas. We start our simulation with a large-scale vortex akin to a hydrodynamic flow and study its non-equilibrium behavior till it attains thermal equilibrium. In the intermediate phases, small wavenumbers (k) exhibit E (k) ∝ k − 3 kinetic energy spectrum, whereas large wavenumbers exhibit E (k) ∝ k spectrum. Asymptotically, E (k) ∝ k for the whole range of k , thus indicating thermalization. These results are akin to those of Euler turbulence despite complex collisions and interactions among the particles. • Demonstration of energy transfers in real gas particles. • Simulation of turbulent flows using grid-free classical molecular dynamics simulation and Direct Numerical Simulation. • The emergence of hydrodynamic energy flux in many particle systems. • Thermalization in a real gas system. [ABSTRACT FROM AUTHOR]

• A novel thermo-mechanical model for high-speed spindle is built. • The electromagnetic loading device is design for spindle test. • Increasing preload restrain the attenuation of spindle natural frequency. • Spindle thermal deformation play a key role on its mechanical behavior. In this paper, based on the multi-degree-of-freedom (M-DOF) finite element and 2-dimensional transient thermal network methods, a novel thermo-mechanical coupling model of the high-speed spindle-bearing system by comprehensively considering the radial coupling deformations of supporting ball bearings and rotor is proposed, and the effects of the temperature rise and thermal deformation on its dynamic characteristics are discussed. Then a non-contact electromagnetic loading device is designed to test the dynamic amplitude-frequency response of a hydraulic variable preload experimental spindle system. The studies show that, the results calculated by proposed thermo-mechanical coupling model are highly consistent with the experimental results of the spindles system, and the temperature rise and thermal deformations have an important influence on its mechanical behavior, and the linear resonant frequency of the high-speed spindle under the constant pressure preload mechanism continues to increase until the system reaches its thermal equilibrium state. [ABSTRACT FROM AUTHOR]

In permafrost regions, where climate change poses significant challenges to infrastructure stability, understanding the thermal behaviour of buildings is crucial. This study conducts a detailed investigation into the thermal performance of elevated buildings in permafrost regions within the context of a changing climate. High-resolution regional climate simulation-informed computational fluid dynamics (CFD) models were developed for northern buildings. The findings indicate that the presence of elevated buildings can disrupt the permafrost's natural thermal equilibrium in the future. This disturbance can extend vertically and horizontally, potentially leading to altered ground temperature gradients and increased air and ground temperatures by 4.25% and 3.85%, respectively. The research findings also highlight a 12.75% reduction in wind speed beneath the study building when transitioning from the local scale (i.e. , single-building) to the neighbourhood scale (i.e. with surrounding buildings). These results underscore the critical significance of exploring the neighbourhood scale in building design and planning within permafrost regions, emphasizing the need for comprehensive assessment tools to inform effective strategies and decisions. The holistic approach adopted in this study, sets out a clear vision to guide northern adaptation initiatives that address some of the climate change issues in the buildings' design by utilizing integrated climate system-built environment modelling. • Developed a computational workflow to assess building thermal impacts on permafrost. • Utilized GEM-driven CFD simulations to evaluate thermal performance under climate change. • Analysed the influence of building and neighbourhood scales on thermal performance. [ABSTRACT FROM AUTHOR]

The increasingly powerful computing capabilities of 5G technology are posing greater heat dissipation challenges for communications base stations. Passive radiative cooling, as a promising cooling strategy without energy consumption, however, is severely limited by its insufficient cooling power especially in the face of high heat flux conditions. Herein, we report a tri-function passive radiative cooler (TPRC) to enhance the cooling capacity through the synergistic effect of broadband radiative cooling, latent heat storage, and directional thermal conduction. Vacuum-assisted self-stacking, skeleton absorption and coating methods are used to fabricate TPRC. Under the heating power density of 4000 W/m2, TPRC lowered the thermal equilibrium temperature to 74.1 °C, a reduction of 16 °C and 3.7 °C compared to the bare aluminum plate and single radiative film, respectively. The contributions of these three cooling types were analyzed and it revealed that optimizing thermal conduction can effectively improve cooling efficiency. Our work provides a comprehensive strategy for expanding the application of passive radiative cooling to high power density devices. [Display omitted] • Radiative cooling, latent heat storage and directional thermal conduction were integrated to fabricate TPRC. • TPRC lowered the thermal equilibrium temperature compared to tradition radiative film under high heating power density. • Thermal conduction along the zenith direction was the optimal design for above-ambient radiative cooling. • Non-radiative thermal conduction was verified to be the dominant mode of cooling through theoretical calculations. [ABSTRACT FROM AUTHOR]

In this study, we model quantum decoherence using quantum Brownian motion for a particle in a Pöschl-Teller potential interacting with an environment of non-interacting harmonic oscillators in thermal equilibrium. We employ a generalized su(1,1) algebra to define a position-like operator for the particle, which we use to set the interaction Hamiltonian. Utilizing the Born-Markov master equation, we investigate the decoherence coefficient and derive a specific frequency for the particle that influences the decoherence term. Additionally, we demonstrate that in a particular limit, this frequency matches that of a harmonic oscillator, thereby aligning the decoherence behaviour of the Pöschl-Teller potential with that of a harmonic oscillator. • The Born-Markov master equation reveals decoherence in the Pöschl-Teller potential. • Generalized su(1,1) algebra defines position- and momentum-like operators in the Pöschl-Teller potential. • In a specific limit, decoherence in the Pöschl-Teller potential mirrors that of a harmonic oscillator. [ABSTRACT FROM AUTHOR]

This study comprehensively evaluates the thermal upheaval buckling of a functionally graded porous (FGP) pipeline laid on an arched concave seabed. The FGP pipeline is consolidated by graphene platelets (GPL). Symmetric schemes are used for both the pores and the GPL in the thickness direction of the pipeline. The energy method and thin-walled shell theory are adopted to develop analytical frameworks for the thermal instability of the FGP-GPL pipeline. Subsequently, the present results are contrasted with other closed-form solutions, which fully verify the feasibility of this study. Finally, a parametric analysis is conducted, emphasizing the critical temperature variations induced by diverse arch radius, porosity coefficients, graphene weight ratio, and geometric properties of the GPL. It has been found that the thermal stability of the FGP-GPL pipeline is improved by adding more anchors in a certain seabed and laying the pipeline in an arched concave seabed, respectively. The main novelties of the present work are summarized as: (1). develop analytical schemes to provide design guidance for practical applications as an FGP-GPL pipeline lays on an arched concave seabed; and (2). plot explicitly thermal equilibrium curves to illustrate the stability mechanism of an FGP-GPL pipeline laid on an arched concave seabed, respectively. • The FGP-GPLs pipeline deforms radially at a minimum temperature variation. • The critical temperature variation is predicted for the pipeline laid on the arched seabed. • Explicit equilibrium curves are illustrated for the pipeline laid on the arched seabed. • The arched seabed is helpful to resist the thermal buckling of the FGP-GPLs pipeline. [ABSTRACT FROM AUTHOR]

This work applies the methods of statistical mechanics to two processes relevant to thermoluminescence; (1) the charging of traps, and (2) the discharging of traps. Assuming thermal and diffusive equilibrium, we calculate the trap ionization probabilities over a wide temperature range and for a variety of traps in YAG:Ce. The goal is to investigate whether a statistical approach yields results consistent with experimental thermoluminescence observations. We are able to reproduce with good accuracy the glow curves of several traps observed in YAG:Ce. Our calculated glow curves are shown to be consistent with systems exhibiting second order kinetics. For systems of traps that are at or near thermal and diffusive equilibrium with the conduction electrons, the results indicate that the position of a glow curve peaks is determined by two factors: the trap depths and the density of conduction electrons. • Statistical approach to thermoluminescence in YAG:Ce is presented. • Glow curve peaks based on statistical approach show a good fit to observed experimental data. • Glow curve peak positions depend on trap depths and conduction electron density. • The theoretical glow curve band structure using the statistical approach is consistent with second-order kinetics. [ABSTRACT FROM AUTHOR]

Battery thermal management system is important for improving the efficiency, lifespan, and safety of new energy vehicle batteries. An energy-efficient model predictive control algorithm based on dynamic programming solver is proposed for battery thermal management strategy. A control-oriented nonlinear battery thermal model is established for predicting temperature changes in thermal management system. The dynamic programming algorithm is utilized to solve the nonlinear optimal control problem, which includes state boundary calculation and optimal control sequence backward calculation. The effects of the weighting parameters and other hyperparameters in the proposed control strategy on the control performance are investigated to achieve the optimal trade-off between thermal equilibrium temperature control, computational efficiency, and energy savings. The simulation results show that the proposed strategy can achieve considerable energy savings in high and low environment temperatures, as well as under standard and real driving conditions. Compared to the on-off based strategy and proportional control-based strategy, the proposed strategy saves up to 8.94 % and 8.33 % of actuator energy at an environment temperature of −20 °C, and up to 77.83 % and 99.83 % of actuator energy at an environment temperature of 40 °C, utilizing the energy consumption of the proposed strategy as a baseline. • An energy-efficient battery thermal management strategy is proposed. • A control-oriented nonlinear battery thermal management model is established. • The effect of wide environment temperature range disturbance on TMS is analyzed. • The selection of the algorithmic hyperparameters is investigated. [ABSTRACT FROM AUTHOR]

Non-homogeneous hydrolysis extent was able to be accurately described by a product of logistic with exponential convex growth function because of slow collision-complex formation between activated H 2 O and HD molecule to non-linearly couple with transition state decay according to Chain Reaction and Transition State theory, while the homogeneous has grown up only in an exponential convex function because of fast collision-complex formation to make its initial extent ratio extremely quickly close to unity. [Display omitted] • Extent equations for hydrolysis of Sulfur mustard are newly proposed. • An exponential convex growth function for homogeneous hydrolysis extent. • Its product with a logistic growth function for non-homogeneous hydrolysis extent. • Their rate constants strongly depend on initial and boundary conditions. • They are limited by the internal quantum state number of bi-molecular structure. This paper aims to establish a hydrolysis extent equation and rate dependence of initial and boundary conditions for sulfur mustard (HD) non-dissolved and dissolved in water by the following work. Firstly, non-homogeneous hydrolysis extent was found to be accurately described by a product of logistic with exponential convex growth function because of slow collision-complex formation between activated H 2 O and HD molecule to non-linearly couple with transition state decay, while the homogeneous has grown up only in an exponential convex function because of fast collision-complex formation to make its initial extent ratio extremely quickly close to unity. Secondly, initial non-temperature effects from (ethanol, acid, base) additives, HD concentration and droplet size, and rotation speed on hydrolysis rate could be summarized into a Boltzmann function of rate constant with initial molar free energy because of a thermal equilibrium distribution of internal quantum state at a given energy for bi-molecular structures before and after complexing. The results from 5 mL solution under vortex was nearly similar to the stirring 100 mL solution and would helpfully clarify the detoxification kinetics to establish a standard method for evaluating reactivity of aqueous decontaminants against chemical warfare agents at necessarily specified conditions. [ABSTRACT FROM AUTHOR]