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X-ray self-heating is a common by-product of X-ray Free Electron Laser (XFEL) techniques that can affect targets, optics, and other irradiated materials. Diagnosis of heating and induced changes in samples may be performed using the x-ray beam itself as a probe. However, the relationship between conditions created by and inferred from x-ray irradiation is unclear and may be highly dependent on the material system under consideration. Here, we report on a simple case study of a titanium foil irradiated, heated, and probed by a MHz XFEL pulse train at 18.1 keV delivered by the European XFEL using measured x-ray diffraction to determine temperature and finite element analysis to interpret the experimental data. We find a complex relationship between apparent temperatures and sample temperature distributions that must be accounted for to adequately interpret the data, including beam averaging effects, multivalued temperatures due to sample phase transitions, and jumps and gaps in the observable temperature near phase transformations. The results have implications for studies employing x-ray probing of systems with large temperature gradients, particularly where these gradients are produced by the beam itself. Finally, this study shows the potential complexity of studying nonlinear sample behavior, such as phase transformations, where biasing effects of temperature gradients can become paramount, precluding clear observation of true transformation conditions. [ABSTRACT FROM AUTHOR]

One of the main methods for obtaining information about the generation of sound pulses in metals is to measure the reflection coefficient of a probe wave. Various theoretical models are used to interpret the results of measuring the contribution to reflection coefficient Δ R (t) due to sound-generated displacements of lattice atoms. The purpose of this paper is to establish the degree of accuracy of models used in the case of sound generation in thin films exposed to a femtosecond pulse. It is shown below that the assumption of uniform heating used for thin films is justified if the film thickness is less than the film heating depth and for thicker films at times greater than the film heating time over the entire thickness. For optically thick films, a relatively simple expression for the field can be used. If the film thickness is less than the skin layer depth of the pump field, then it is necessary to consider the field reflection from a substrate. In this case, depending on the optical properties of the metal and the substrate, taking into account reflection can lead to either an increase or a decrease in Δ R (t). It has been established that if the skin layer at the frequency of probe radiation is less than the film heating depth, then taking into account temperature gradients in the equation for the displacement of lattice atoms leads to small changes in Δ R (t). This makes it possible to significantly simplify calculations of the displacement of lattice atoms. [ABSTRACT FROM AUTHOR]

Purpose: To measure the surface temperature distribution after using a CO2 laser to heat titanium dental implants via different power settings, application intervals, and irradiation times. Materials and Methods: A total of 10 tissue-level titanium implants (Screw-Line Promote Plus, Camlog; 4.3 × 11 mm) were placed (EpoFix, Struers) and irradiated with a CO2 laser (Denta 2, Lutronic) with a wavelength of 10.6 µm at power levels of 4 watts (Group 1), 6 watts (Group 2), 8 watts (Group 3), and 10 watts (Group 4). A continuous beam mode (setting I) and noncontinuous beam modes with 5-second (setting II) and 10-second (setting III) pause intervals were used. For each setting, a total irradiation time of 50 seconds was used and repeated 10 times. The temperature was measured using external thermocouple (Testo) in contact with the implant surface at the implant shoulder, middle, and apex. A linear regression model was used to analyze the data (P = .05). Results: Setting I demonstrated the most rapid increase in implant surface temperature in all three test sites as well as the greatest total temperature at 50 seconds of irradiation time. The greater the pause interval (settings II and III) during the 50 seconds of irradiation, the lower the rate of temperature increase as well as the total temperature in all three test sites and with all power levels. The average temperature difference between the apex and shoulder site was significant for setting III for all groups, but not for any groups in settings I and II. Conclusions: Heating the internal aspect of an implant with a CO2 laser produces different temperature distribution profiles depending on the laser power level and the application interval. Laser-beam irradiation leads to a temperature gradient, which is greatest at the implant apex and smallest at the implant shoulder. [ABSTRACT FROM AUTHOR]

Magnetic and magnetocaloric properties of L a 0.85 S r 0.15 M n 0.99 F e 0.01 O 3 perovskite oxides are investigated in the framework of the mean-field theory with a goal to develop a comprehensive model with parameters that can be used to optimize the caloric performances for cooling applications. Using the experimental magnetic isotherms M(H,T), we estimate and compare the exchange parameter (λ) , the saturation magnetization (M 0) , the total angular momentum (J) , and the gyromagnetic factor (g) for two different samples annealed at 1170 and 1250 °C. These parameters are used, in turn, in the simulation of the magnetic and the magnetocaloric properties of these L a 0.85 S r 0.15 M n 0.99 F e 0.01 O 3 compounds assuming imperfect samples with compositional and/or magnetic inhomogeneities. For this purpose, a Gaussian distribution of the Curie temperature is assumed. The temperature dependence of the magnetic entropy change, − Δ S M (T) , resulting from an applied field variation is simulated for both samples. The selected distribution captures the rounding of the − Δ S M (T) peak at its maximum and its broadening with growth conditions, features that are constantly observed in many bulk polycrystalline compounds. [ABSTRACT FROM AUTHOR]

Numerical methods for analyzing diffusion phenomena involving strong discontinuities and complicated interfaces are of great scientific and technical importance. In this paper, we extend the existing step-balanced random walk, which overcomes the problem of detailed balance of a random walker in three-dimensional (3D), diffusion-tensor discontinuous systems, to particle density (ρ) discontinuous systems, and introduce volumetric heat capacity C and temperature T by considering ρ as heat density, i.e., ρ = C T , to apply it to thermal problems. Two types of thermophysical simulations are demonstrated: one is steady-state heat flow due to a temperature difference at the end surfaces on a two-phase slab model unit cell with periodic boundary conditions; the other is the time variation of temperature distribution due to heat diffusion from a point heat source in a repeated two-phase slab model with no periodic boundary conditions. We see the correct behavior of heat and temperature expected in 3D discontinuous systems composed of two phases with anisotropic thermal conductivity. The applicability to problems other than pure diffusion and the limitations of the method are also discussed. [ABSTRACT FROM AUTHOR]

We report the development of a novel variant of cavity ringdown polarimetry using a continuous-wave laser operating at 532 nm for highly precise chiroptical activity and magnetometry measurements. The key methodology of the apparatus relies upon the external modulation of the laser frequency at the frequency splitting between non-degenerate left- and right-circularly polarized cavity modes. The method is demonstrated by the evaluation of the Verdet constants of crystalline CeF3 and fused silica, in addition to the observation of gas- and solution-phase optical rotations of selected chiral molecules. Specifically, optical rotations of (i) vapors of α-pinene and R-(+)-limonene, (ii) mutarotating D-glucose in water, and (iii) acidified L-histidine solutions are determined. The detection sensitivities for the gas- and solution-phase chiral activity measurements are ∼ 30 and ∼ 120 μdeg over a 30 s detection period per cavity round trip pass, respectively. Furthermore, the measured optical rotations for R-(+)-limonene are compared with computations performed using the TURBOMOLE quantum chemistry package. The experimentally observed optically rotatory dispersion of this cyclic monoterpene was thus rationalized via a consideration of its room temperature conformer distribution as determined by the aforementioned single-point energy calculations. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been widely used in exploring the nucleation behavior of many systems, including gas hydrates. Gas hydrates are ice-like solids in which gas molecules are trapped in water cages. During hydrate formation, a considerable amount of heat is released, and previous work has reported that the choice of temperature control scheme may affect the behavior of hydrate formation. The origins of this effect have remained an open question. To address this question, extensive NVE simulations and thermostatted (NPT and NVT) simulations with different temperature coupling strengths have been performed and compared for systems where a water nanodroplet is immersed in a H2S liquid. Detailed analysis of the hydrate structures and their mechanisms of formation has been carried out. Slower nucleation rates in NVE simulations in comparison to NPT simulations have been observed in agreement with previous studies. Probability distributions for various temperature measures along with their spatial distributions have been examined. Interestingly, a comparison of these temperature distributions reveals a small yet noticeable difference in the widths of the distributions for water. The somewhat reduced fluctuations in the temperature for the water species in the NVE simulations appear to be responsible for reducing the hydrate nucleation rate. We further conjecture that the NVE-impeded nucleation rate may be the result of the finite size of the surroundings (here the liquid H2S portion of the system). Additionally, a local spatial temperature gradient arising from the heat released during hydrate formation could not be detected. [ABSTRACT FROM AUTHOR]

In water-guided laser technology, the stability of water jets is crucial to ensure the efficient transmission of laser energy. However, the thermal effects generated when high-power lasers are coupled with water jets are bound to impact the stability of the water jets, thus becoming a critical issue that restricts the development of high-power water-guided laser technology. In addressing this issue, this paper establishes a temperature model for coupling high-power lasers with water jets. Subsequently, with validation of the model's effectiveness through experimental data, simulations are conducted to analyze the temperature distribution within the water jet. During the simulation process, lasers with different parameters were coupled with water jets to analyze the temperature variation law of the water jets. Additionally, the maximum laser power coupled with water jets of different lengths was solved. Based on the calculated temperature values of the water jet, simulate the evolution of its profile over time when it has an initial temperature gradient. Simultaneously, perform a three-dimensional reconstruction of the obtained perturbed profile and conduct ray tracing to analyze the laser's transmission losses within the perturbed profile. Finally, high-speed cameras are utilized to capture the profile of the water jet, validating the laser-induced fragmentation behavior in the water jet. The research findings will provide a significant reference value for selecting laser parameters and controlling thermal effects in water-guided high-power technology. [ABSTRACT FROM AUTHOR]

High-strength aviation gears are notably challenging to grind, primarily due to an increased risk of grinding burn. Consequently, the precise and efficient prediction of the three-dimensional temperature distribution throughout the grinding process of aviation gears is crucial. This study focuses on aviation gear in 12Cr2Ni4A material, devising a dynamic, time-variant triangular heat source model alongside a method for calculating the three-dimensional grinding temperature field for aviation gears. By proposing an accurate loading algorithm for the boundary conditions of the moving heat source load on the spatially curved surface in the grinding area and then directly solving the heat transfer differential equation constructed in a fully discrete form based on the principle of minimum potential and the Ritz method, a high-strength aviation gear grinding temperature field prediction model has been established. The accuracy of this proposed method was confirmed through experimental temperature measurements of gear grinding and by comparing these results with those obtained from standard finite element software. The results show that the maximum relative error between prediction values and experimental data is less than 5%. Moreover, when contrasted with the simulation results of standard finite element software, the present approach exhibits superior computational efficiency and accuracy. The developed numerical method reliably forecasts the temperature distribution throughout the gear grinding process and provides a significant reference for precise and efficient temperature field calculations. [ABSTRACT FROM AUTHOR]

The present work improves a phenomenological plasma-assisted combustion model by integrating the spatiotemporal distribution of plasma power density, thereby considering the evolution of plasma streamers in the modeling, and subsequently, better predicting the ignition kernel evolution. The improved phenomenological model is validated against experiments representing the plasma discharge and post-discharge ignition kernel evolution. Specifically, the new model demonstrates a more accurate prediction of ultrafast gas heating and O2 dissociation during the plasma discharge, compared to the original model. In addition, the new model is found to closely match the experimental pressure wave and heated channel profiles post-discharge without the need for tuning the energy deposition (unlike the original model), highlighting its accuracy of post-discharge ignition kernel dynamics. The improved phenomenological model is then employed to investigate ignition kernel evolution for a stoichiometric methane-air discharge across various discharge gap configurations. Simulations reveal a non-uniform temperature and streamer distribution progressing from the electrode tips toward the center, contrasting uniform cylindrical discharges previously described in the original model. Streamer propagation is observed to be faster for larger gaps when maintained at the same average electric field for different discharge gaps. The tendency of smaller gaps to produce detached toroidal ignition kernels is observed, while larger gaps promote cylindrical and attached ignition kernels. Interactions between successive ignition kernels from consecutive discharges varied significantly, with the smallest gap (1 mm) promoting the quenching of the preceding ignition kernel due to the initial kernel–kernel separation. The intermediate gap (2 mm) promotes detached kernel growth. In contrast, in the largest gap (4 mm), kernels consistently combine and expand attached to electrodes. The impact of homogeneous isotropic turbulence is also explored, showing the persistence of ignition kernels early on but eventually quenching due to enhanced radical and heat losses with pronounced turbulence intensity. [ABSTRACT FROM AUTHOR]

In this work, a steady-state, three-dimensional and non-isothermal numerical model for a proton exchange membrane electrolysis cell (PEMEC) is established. Based on this model, the distribution of catalyst loading is specifically designed according to the flow characteristics of both parallel and serpentine channels. In general, the catalyst loading is progressively reduced from inlet to outlet along the flow direction to match the local water content, leading to an innovative segmented catalyst layer which has not been studied yet for PEMEC applications. The electrochemical behavior of different segmentation schemes is investigated by comparing their polarization curves normalized by either electrode area or catalyst loading, while other physical fields such as velocity, pressure, water mole fraction and temperature distributions are also characterized. The numerical results reveal that a reasonable distribution of catalyst can reduce its amount of usage while still maintaining most of the PEMEC performance. In other words, the cost performance is significantly improved. This is mainly attributed to the full use of uneven water distribution in the flow channel, which improves the catalyst utilization efficiency significantly. This strategy is proved to be effective for both serpentine and parallel channels, ensuring a broad application prospect. • A novel catalyst layer segmentation strategy is proposed for PEM electrolyzer. • The catalyst loading is distributed according to the local water content. • Specific current normalized by catalyst weight is improved due to loading reduction. • Physical field distribution inside the PEM electrolyzer is not changed too much. • Cost performance of the PEM electrolyzer is improved significantly. [ABSTRACT FROM AUTHOR]

Utilization of actinides and rare earth elements is only possible by separating these metals with high purity. The materials used in separation must have thermal, chemical, mechanical, and radiation resistance. In the present study, separation experiments of actinides and rare earth elements (REEs) were carried out using purified H2SO4 leach liquor. Polyacrylonitrile (PAN)-supported Ti, Zr, and Si oxide nanocomposites were tested for the selective separation of Th, U, Gd, Eu, Sm, Pr, Nd, La, Ce, and Y. The effects of pH, contact time, adsorbent/solution ratio, and temperature on distribution coefficient (KD) and adsorption capacity (Q) were investigated. The synthesized nanocomposites tend to separate the elements into two main groups: Th, U, Gd, Eu and Sm, Pr, Nd, La, Ce. Notably, it was observed that the separation of Th and U from the remaining elements is promising at 15 °C. Additionally, the separation can be further improved depending on the differences in desorption efficiency. [ABSTRACT FROM AUTHOR]

Piezoelectric fan is widely used in electronic products heat dissipation. Channel arrangements affect the cooling performance. Flow and temperature distributions in five schemes: (1) large space, (2–4) top opening channels with different restricted extents, and (5) channel with four enclosed sides) were investigated. Time average velocity distributions reveal the flow characteristics of two high-speed cooling fluids forming from blade roots. The cooling fluids gradually converge in the middle of blade tips and disperse downstream. Scheme (5) has the highest velocity of 8 m/s due to the strongest sucking and driving effects of negative and positive pressure zones. Air ventilation rates of schemes (1–5) cover the range from 1.21 × 10−3 to 2.07 × 10−3 m3/s. For schemes (1–4), the maximum ventilation always comes from top boundary, with the percentage above 80%. Among all schemes, the maximum temperature of scheme (1) is lowest, which is 467.401 K. However, the highest space-time average heat transfer coefficient is obtained in scheme (1), up to 54.02 W/(m2·K). The value decreases sequentially in schemes (5, 2, 4 and 3). Mismatch between main flow velocity and heat transfer coefficient highlights the three-dimensional sucking effect of piezoelectric fan. [ABSTRACT FROM AUTHOR]

Unlike previous studies that predominantly focused on uni-directional functionally graded materials (FGMs), this work extends the analysis to bi-directional FGM shell panels with various geometries, offering a more comprehensive understanding of their thermal buckling behavior. For the first time, a combination of higher-order shear deformation theory and the p-version finite element method is utilized in this context. Moreover, a novel nonlinear temperature distribution solution derived from the steady-state thermal conduction equation for bi-FGMs is proposed, addressing a significant gap in the existing literature. The investigation explores the effects of curvature, aspect ratio, thickness ratio, and material gradient on the buckling response of shell panels under thermal loading. The study begins with the mathematical formulation of the problem, laying the groundwork for the subsequent analyses. To ensure the accuracy and effectiveness of the custom-made code, a rigorous comparative study is performed. The analysis then extends to examining the impact of material gradient indexes on the shell's behavior, focusing on variations in buckling temperature rise, mode shapes, and normalized modal stress distribution. Additionally, the investigation includes a comparative analysis of three different types of temperature distributions, considering both temperature-dependent and temperature-independent material scenarios. [ABSTRACT FROM AUTHOR]

Owing to the direct exposure to complex atmospheric environments, the temperature field of composite box girder bridge with corrugated steel webs (CBGB-CSW) is likely non-uniformly distributed. Whereas, the current researches regarding the thermal responses of CBGB-CSW are insufficient, and the thermal responses of CBGB-CSW under solar radiation are still unknown. Therefore, this paper conducted a long-term temperature experiment on a scaled model to explore the temperature distribution characteristics in CBGB-CSW. Meanwhile, a three-dimensional thermal–mechanical coupling Finite Element (FE) model is established to simulate the temperature field in the experiment girder. The accuracy and effectiveness of the developed FE model has been verified by the measured temperature data. Therewith, the thermal responses (i.e., stress and displacement) of a full-scale continuous CBGB-CSW with a span of 150 m are numerically investigated. The results indicate that the maximum stresses always occur at the midspan section (with a depth of 5 m) of the continuous CBGB-CSW, and considerable concentrations of stress are observed in the steel-concrete junction. The maximum longitudinal tensile and compressive normal stresses within 0.4 m of the upper junction can reach 5.55 MPa and −8.46 MPa respectively, and those of the lower junction can reach 6.96 MPa and −7.05 MPa respectively. Besides, owing to the impacts of vertical and horizontal temperature gradients, significant displacements of the whole bridge can also be observed. The maximum vertical displacement (5.33 mm) of the CBGB-CSW is estimated at the top plate in the midspan, while the maximum horizontal displacement (0.74 mm) is estimated at the trough of the southern corrugated steel web in the midspan. Notably, the outcomes of this paper can provide some useful references for engineers and scholars to understand the thermal responses of the CBGB-CSW. [ABSTRACT FROM AUTHOR]

The heat transfer coefficient, including interfacial heat transfer coefficient (IHTC) and convective heat transfer coefficient (CHTC), plays a pivotal role in the thermal dynamics of hot gas forming processes. This parameter can determine the temperature field, thereby affecting the deformation and mechanical properties of the material to improve productivity. In this paper, we present an innovative experimental apparatus designed to measure the temperature evolutions of the aluminum specimen and the die during the hot gas forming processes. This apparatus is capable of simultaneously measuring IHTC and CHTC. Using the inverse finite element method, the simulated temperature histories are matched with empirical data and the best-fit values are adopted as indicative of IHTC and CHTC. This study identified the effects of contact pressure and die temperature on IHTC, as well as the impact of gas pressure on CHTC. In addition, a predictive model was developed to forecast the IHTC and CHTC at varying contact pressures and die temperatures with a prediction accuracy surpassing 0.95. By leveraging the predictive model presented in this paper, users can modulate contact pressure and die temperature based on specific production needs to achieve a targeted temperature profile. This method offers enhanced precision in managing the temperature field of the workpiece during hot gas forming experiments, thereby refining the temperature distribution. Moreover, it optimizes the formability and microstructural attributes of the material, ultimately leading to improved mechanical characteristics. [ABSTRACT FROM AUTHOR]

Roll coating plays a major role in industrial coating, including wallpapers, plastic and photographic films, sticky tapes, magnetic recordings, wrapping magazines and books, and so on. The current study proposes a mathematical model for a non‐isothermal, incompressible Sutterby fluid flowing through a narrow gap between two heated, counterrotating rollers. Lubrication approximation theory is used to simplify nondimensional expressions. The perturbation technique provides exact results for velocity profile, temperature, flow rate, and pressure gradient, whereas the numerical technique (Simpson rule) is used to compute the pressure profile and flow rate, respectively. The effects of the involved parameters on various physical characteristics like pressure, flow rate, temperature, pressure gradient, force, and power input are depicted in graphs and tabular form. A mechanism for controlling the coating thickness, power input, flow rate, separation force, and pressure distribution is provided by the material properties involved. With variations to a Sutterby fluid parameter β $\beta $ and the velocity ratio K, both the pressure gradient and pressure decrease. It is significant to note that the temperature distribution is controlled by the velocities ratio and Brinkman number. Moreover, the separation point is shifted towards the nip area and the coating thickness on the web reduces with increasing velocities ratio K. [ABSTRACT FROM AUTHOR]

In this paper, we consider a mathematical model, which has a unique mechanism of heat transfer in the stretching/shrinking straight fin with an exponential profile. The thermal conductivity, internal heat generation, and heat transfer coefficient are considered temperature‐dependent. Heat is exposed to the surroundings by convection and radiation. The governing differential equation and boundary conditions are presented in a dimensionless form. In our study, we considered variable surface emissivity, that is, a constant, and the linear function of a temperature. The convective heat transfer parameter is considered a power‐low type. The novelty of this work is the application of temperature‐dependent surface emissivity, and the problem is solved by the Legendre wavelet collocation method. A comparative analysis of the present results in the context of previous findings is presented in the form of a table for validation and found exactly the same. The impacts of distinct variables are presented in the form of figures and discussed in detail. The present analysis is focused on real‐world applications and offers valuable insights for improving the design of fins. [ABSTRACT FROM AUTHOR]

In this study, an efficient optimization framework was developed to determine the parameters of through‐silicon vias and the layout of heat sources in three‐dimensional integrated circuits (3D ICs), employing an artificial neural network (ANN) reduced‐order model in conjunction with a Bayesian optimization (BO) algorithm. The proposed method effectively predicts the temperature distribution in 3D ICs and refines their thermal parameters, offering solutions to thermal management challenges. Latin hypercube sampling was utilized for data sampling, enhancing the previously established rapid thermal analysis method through parameterization of heat source locations. The temperature distribution data for varying hotspot locations in 3D ICs were fitted using an appropriately defined objective function, leading to the development of a reduced‐order ANN model that accelerates temperature prediction. The computational results demonstrate that the neural network model exhibits a deviation in predicted values of less than 2%, and the coefficient of determination R2 approximately 0.93, underscoring high predictive accuracy. Additionally, the optimization outcomes and the efficiency of the selected BO algorithm were thoroughly evaluated. Notably, the BO algorithm achieved the global optimum in just 4.07 s across 250 iterations, demonstrating an effective power distribution strategy for the 3D ICs model. [ABSTRACT FROM AUTHOR]

This paper explores the impact of temperature on the fractionalization of magnetic nanoparticles in blood, coupled with vibratory motion influenced by rotation. The distribution systems exhibit heightened diffusivity, explored numerically through the finite difference method and the L1 ${L}_{1}$ algorithm. The temperature distribution robustly responds to elevated fractional parameters, indicating a critical threshold. The study achieves a comprehensive understanding of temperature and velocity evolution in different tube zones. In comparison, single‐walled carbon nanotubes surpass multiple‐walled carbon nanotubes in distributions, while CuO nanoparticles demonstrate larger distributions at an average fractional‐order parameter of α=0.5 $\alpha =0.5$. In the observed growth region at α=0.73,Fe2O3 $\alpha =0.73,{\text{Fe}}_{2}{{\rm{O}}}_{3}$ and TiO2 ${\text{TiO}}_{2}$ exhibit noteworthy temperature distributions, highlighting the fractional derivative's impact in highly diffusive models with nanoparticles. It is also noted that in this region, the temperature distribution tends to decrease for all the parameters and values examined, particularly at a low Reynolds number (Re=0.5 ${R}_{e}=0.5$). However, the introduction of nanoparticles accelerates the processes and distributions across the various observed zones. Furthermore, the accelerated behavior of each nanoparticle can be moderated based on its sphericity. By encompassing all facets of fractional order for controlled rotations, the study sheds light on the role of magnetized nanoparticles in blood dynamics, emphasizing the significance of a critical zone where certain physicochemical properties are disrupted, potentially leading to cellular disorders, and the fluidodynamic effects of vortex flow. This perspective is pivotal for addressing tissue lesions induced by vibrations, as seen in the case of coagulations, and for targeting carcinogenic areas using nanoelements. [ABSTRACT FROM AUTHOR]

This paper employs the inclusion-based boundary element method (iBEM) to delve into heat transfer phenomena in composites. Initially, we integrate the heat flow function and ellipsoidal integral into a bounded domain containing multiple ellipsoidal inhomogeneities. The eigen-temperature gradient is utilized to simulate the thermal mismatch between inhomogeneities and the matrix. Subsequently, the temperature field is computed considering boundary heat flux and temperature conditions, eigen-temperature gradient, and virtual heat source acting on inhomogeneities. The eigen-temperature gradient and virtual heat source are then solved using the equivalent heat flow conditions to obtain the steady-state heat conduction results within the bounded domain. Through comprehensive numerical examples, we analyze the temperature distribution within composite and scrutinize the impact of particle shapes, orientations, volume fractions, and thermal conductivity ratios on the effective thermal conductivity of composite. Furthermore, we explore the distinctive properties of functional gradient material. Additionally, a comparison between iBEM and the finite element method is conducted. The findings reveal a progressive enhancement in the thermal conductivity of composite as the particle shape transitions from spherical to fibrous. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) have gained great attention as a stationary power generation application due to their high efficiency, fuel flexibility and environmental friendliness. The devices and power age could be revolutionized with the commercialization of these technologies. The SOFC-based stationary power generator is one step closer to commercialization however, it is delayed due to the inherent bottleneck of insufficient long-term durability. The cathode current collecting layer (CCCL) is crucial in stack applications to minimize the contact loss between cell and metallic interconnects. Herein, we report an easy-to-fabricate and highly robust CCCL to boost electrochemical performance and long-term durability of flat tubular (FT) short stack. The tailored structure of the CCCL was employed in the fabrication of the FT short-stack. The G/Ag porous structure exhibited increased porosity of 61.2 %, thereby enhancing the mass transport and improving the overall performance and long-term durability. The four-cell FT stack was manufactured without an interconnect and open air-gas channel. Subsequently, the FT short-stack is tested for performance and long-term durability for elapsed 5000 h at a chronopotentiometry test. The porous layer of graphite/Ag on the cathode layer maintained structural integrity without defects and mechanical failure. Consequently, the stack voltage remains stable throughout operation owing to improved structural stability and uniform temperature distribution across four FT cell stack. [Display omitted] [ABSTRACT FROM AUTHOR]

To achieve efficient cooling capabilities in electric vehicle (EV) batteries, battery thermal management systems with higher power density have garnered significant attention. This work introduces a novel computational analysis method to assess the temperature distribution within the designed multiple EV battery cooling module's, investigating the flow of both water and silver-based nanofluids as coolants. The EV battery module under study comprises ten cylindrical lithium-ion batteries of model 18,650 types. This comprehensive simulation considered various factors, such as the coolant's flow path, flow rate and type, appear to have significantly influencing temperature distribution. The analysis identifies "Case IV" as the most effective cooling configuration utilizing water as the coolant and demonstrating superior cooling capabilities compared to the conventional cooling module ("Case I"). This finding marks a critical step toward optimizing battery cooling methods and achieving efficient thermal management. The incorporation of silver nanoparticles in the base fluid (water) enhances the nanofluid's thermal conductivity and heat transfer efficiency, showcasing improved cooling capabilities beyond that of water alone. The performance of different nanofluid concentrations including 0.25% and 0.50% by volume was evaluated to demonstrate their impact on battery cooling efficiency. To contextualize the results, the cooling performance of silver nanofluids has been compared with that of TiO2 nanofluids reported in previous studies. The outcomes of this research underscore the potential of the computational analysis technique to advance temperature management systems for EV batteries, improving EVs performance and reliability and contributing to a more sustainable and efficient future of transportation. [ABSTRACT FROM AUTHOR]

The slip flow behavior in nanofluid is necessary in industrial and engineering systems. Thermal and concentration slip is very important to enhance the heat and mass transport in micro-channels, artificial heart valves polishing, emulsion, suspended substances, foaming, internal heart cavities, and polymerization treatments. The movement of the fluid in the slip flow pattern is quite distinct from the conventional flows. The main aim of present research is to examine the thermal and concentration slip effects on heat and mass transport of magneto-nanofluid across stretchable surface in the presence of viscous dissipation and thermal density. The mathematical model is developed in terms of partial derivatives and converted into ordinary form by using similarity variables and stream functions. By using similarity and stream variables, the significant physical parameters such as Eckert number, modified buoyancy parameter, Prandtl parameter, density parameter, Brownian factor, and slip factors are generated. The numerical outcomes are elaborated by using Keller–box scheme with Newton–Raphson method. The velocity of nanoparticles, temperature, and concentration distributions are the main key findings of this research. It is noticed that the temperature distribution exponentially increases as density parameter increases. It is examined that the significant slip behavior in thermal and concentration increases as Eckert number increases. It is found that significant variations in slip velocity and slip temperature are examined for each slip parameter. The magnetic-driven stretchable surface is very beneficial in cooling strips, microelectronics, heat insulation, energy storage devices, micro-MHD pumps, oil reservoirs, and metal extraction. [ABSTRACT FROM AUTHOR]

In order to provide a reliable tool for thermal-hydraulic simulation of pebble bed high temperature gas-cooled reactors (HTGRs), a two-dimensional model was developed based on the porous media model and user-defined scalar (UDS) function of FLUENT software. Then, the model was applied to the numerical simulation of the shutdown test of the 10 MW high temperature gas-cooled test reactor (HTR-10) at 9 MW power level, and the temperature distribution and flow field distribution in the reactor were obtained and compared with the results of the experimental data. The reliability of the model in this paper was verified. Based on the model, the effects of the water-cooled panel temperature and the initial core temperature on the thermal-hydraulic characteristics of HTR-10 after shutdown were further explored. The results show that there is a decoupling phenomenon between the residual heat transfer within the core and the heat dissipation of the pressure vessel. The initial core temperature has relatively little effect on the heat dissipation and maximum temperature of the pressure vessel, but it has a significant impact on the thermal characteristics of the core area. [ABSTRACT FROM AUTHOR]

Induction heating of asphalt concrete has the characteristics of high crack repair efficiency and environmental sustainability. However, the uneven temperature distribution and local overheating obstruct its widespread application. Therefore, this paper conducted a pixel-level quantitative analysis of the temperature distribution characteristics and local overheating phenomenon on both the upper and side surfaces of asphalt concrete with different steel fiber (SF) contents after continuous heating. The temperature distribution was visualized by three-dimensional (3D) heat maps and violin maps. The uniformity of temperature was analyzed by the slope absolute value of the linear fitting results and the ratio of the interquartile range to the range. Results indicated that high SF content accelerated the heating rate of asphalt concrete but decreased the temperature uniformity. Localized overheating caused thermal expansion damage in asphalt mixtures, and the sample with 10% SF had both 304.2°C (maximum) and 79.7°C (minimum) upper surface temperatures at 60 s of heating, with local structural disintegration of the mixture. Higher heating uniformity and faster heating rates were achieved for samples with 6% SF content. The heating rate decreased with increasing heating time. The upper surface of the sample with 8% SF can be heated up the fastest (2.28°C/s). It is recommended that the maximum temperature of the upper surface be controlled during induction heating to avoid thermal damage. This proposal provides a reference for the practical application of induction heating technology. [ABSTRACT FROM AUTHOR]

This study explores the performance of a steady-state flow single-phase non-conductive liquid immersion cooling system in a single-cell Li-ion battery under a variety of thermal environments such as 25°C, 40°C, and 60°C and tested at different charge C-rates. The experimental results show that the proposed cooling system exhibited the best cooling performance of less than 5°C and a significant temperature rise reduction of 34% at 3C rate under the ambient temperature of 25°C. Also, it provided uniform temperature distribution within the cell when charged at fast charge rates of 2C and 3C operations. [ABSTRACT FROM AUTHOR]

The motivation of this recent article is to study dusty Walter's B fluid flow due to its wide range of applications in biology and polymer industry. The fluid is traveling peristaltically through an asymmetric channel with wall slip. A discussion is also presented to examine heat transfer effects with thermal radiation and slip. The regular perturbation technique is employed to evaluate the mathematical model of the problem, which is first simplified by using stream functions. Mathematical results are simulated to illustrate flow characteristics of fluid and solid particles in salient quantities. Also, graphs of temperature distribution of fluid and dust particles have been discussed to study the impacts of various parameters. Walter's B fluid parameter reduces speed of both fluid and dust particles. By increasing thermal slip parameter, temperature transference becomes slower through the fluid, while Brinkman number significantly raises the temperature profile of both fluid and particles. This article presents a theoretical analysis of the problem. Moreover, the characteristics of liquids involved in the plastic industry and medical science can also be understood using the current analysis. Walter's B fluid with dust particle suspension has not been investigated for slip and thermal radiation effects. [ABSTRACT FROM AUTHOR]

A cross‐laminated timber rib panel is a floor system comprising cross‐laminated timber plates rigidly bonded to glued‐laminated timber 'rib' beams. A design method was developed to estimate the fire resistance of cross‐laminated timber rib panels, based on a bending load‐carrying model. The bending load‐carrying model calculates the bending load‐carrying capacity of cross‐laminated timber rib panels based on simulated temperature distributions of numerical models. The numerical models were validated against the experimental results of full‐scale fire resistance tests. The proposed design method is based on the overall approach of the current revised draft of EN 1995‐1‐2:2004, that is, prEN 1995‐1‐2:2023, and provides conservative estimates of the bending load‐carrying capacity. The effective width is one of the most important design parameters and its influence was studied in detail. A limit value of 60% of the effective width according to prEN 1995‐1‐1:2023 is proposed as effective width in fire. [ABSTRACT FROM AUTHOR]

In order to investigate the premixed combustion characteristics of CH4/H2/air in a micro-mixing combustor, the effects of different micro-mixing head-ends (HE1, HE2, HE3) and hydrogen mixing ratios on the temperature distribution, heat transfer process, emission characteristic, flames shape are analyzed. The results show that compared with swirl head-end combustion, the micro-mixing combustion performance is better. Among the three head-ends, HE3 has the best combustion characteristics and stable flames. The temperature distribution in the high-temperature zone is uniform, and low-temperature zone is concentrated near the jet, which can suppress the flashback. The velocity and temperature gradient near the central axis of jet streams show a strong synergistic effect. The flames are plume shaped and flames stability is mainly influenced by the H2 combustion process. Increasing the jet diameter, decreasing the jet spacing and increasing the hydrogen mixing ratio all contribute to the flames stability, but these three methods can stabilize the flames by affecting fluid Reynolds number, interaction between small flames and combustion rate, respectively. Moreover, small jet diameter and high hydrogen mixing ratio can reduce OTDF, which contributes to improve outlet temperature uniformity. [ABSTRACT FROM AUTHOR]

Computational fluid dynamics (CFD) method is a common method to obtain the temperature field distribution within the furnace. However, in order to reduce computational complexity, the numerical simulation involve simplifications in boundary conditions and model parameters. As a result, the temperature field distribution deviates from the actual operating conditions. This paper proposes a numerical temperature field modification method based on flame images. Flame images corresponding to the operational conditions are collected using the Industrial Flame Monitoring System (IFMS). The flame images are preprocessed, and the contour of the flame's core region is extracted using the Mask Region-based Convolutional Neural Network (Mask R-CNN) method. The geometric features of the flame are extracted, and matrix calculations are applied to modify the numerical temperature field. The modified temperature field exhibits a deviation in the combustion center, aligning with the actual operation of the boiler. A comparison between the modified temperature field and the temperature measurements from flue gas shows consistent temperature trends. The absolute error (AE) under different operating conditions is under 8.8 K, and the relative error (RE) remains below 1.3%. The analysis results demonstrate that it can enhance the accuracy of temperature field calculations by the modification from flame image features. [ABSTRACT FROM AUTHOR]

Cable terminal defect detection plays an important role in ensuring the safe and stable operation of high-speed trains. In this paper, a numerical model of the electromagnetic thermal field of overheating defects of cable terminal shielding grids and a method of detecting internal defects of cable terminals—even-order temperature derivative is proposed for quantitative detection of internal defective structures of vehicle-mounted cable terminals. Firstly, a numerical model of the electromagnetic thermal field of cable terminals under the condition of leakage current is constructed, through which the temperature field distribution characteristics of different defective structures are analyzed. Then, the intuitive location of the defective region is obtained by investigating the derivative characteristics of the temperature image, and the depth and intensity of the defects are quantitatively assessed by using the main side peak (MSP) distances and the MSP values extracted from the derivative curves. Finally, the simulation and experimental results achieve the identification of defect structures and the quantitative detection of defect depth and intensity, proving the effectiveness and accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

In this study, upward flame spread over thin charring material under varied ambient pressures and oxygen concentrations diluted with different inert gases was investigated. After symmetric ignition, a small systematic disturbance at the flame base region triggers asymmetric two-sided flames, while the flame tips remain aligned. Afterward, one branch of flame dwells and speeds up in a cycle, associated with periodic smoldering holes, mainly ascribed to the secondary pyrolysis and surface oxidative degradation (smoldering) of the remaining char, while the other branch of flame extinguishes eventually, primarily attributed to the self-induced buoyant blow-off at a low critical Damköhler number associated with finite-rate kinetics. The temperature distribution over the sample surface is obtained by infrared thermal imagers, and six stages of the whole pyrolysis process are roughly divided, which gives a better perspective on the underlying mechanism of these unique combustion behaviors. With the burnout (end) of the primary or secondary pyrolysis processes, the local fuel/oxidant mixture ratio at the flame base region approaches that of the inflammability limit (neutral stable point) where the near-limit flames are extremely sensitive to the environmental disturbances, and thus the flame base instability appears. With the increase of the oxygen concentration, the pressure range of the existence of the unique combustion behaviors narrows down due to intensified chemical reactions and thus the stability of the flame base. Furthermore, compared with the environments diluted in N2, the unique combustion behaviors are more conspicuous in that of CO2 (radiative intervening medium) due to larger molecular weight and lower Lewis number. This investigation into the upward flame propagation will enrich the combustion science at transition regimes such as the fire scenarios after the application of the carbon dioxide fire extinguisher. [ABSTRACT FROM AUTHOR]

The efficacy of vaccine storage is significantly impacted by temperature fluctuations within the cooler, often exacerbated by using phase change materials in existing cooler designs for remote areas. These materials can undergo uneven melting and phase separation, leading to temperature instability and vaccine potency loss. In response to this challenge, the present study introduces a novel design of a portable, locally‐made solar‐powered cooler optimized for longer storage periods. The cooler's performance in terms of temperature distribution, airflow dynamics, and the coefficient of performance (COP) is meticulously examined through computational fluid dynamics (CFD) simulations. The simulated results were validated using experimental data from the open literature, ensuring accuracy and reliability. The findings indicate that the developed cooler achieves significant improvements over traditional models. For instance, the current model reaches a temperature of +12°C in just 84 min, compared to 208 min, as reported in the literature results. Moreover, the current model reaches a temperature of −12°C in 195 min and it has energy efficient with a COP of 4.5. Statistical analysis further confirms the reliability of the simulation results, with root mean square and mean absolute percentage errors of 6.587 and 24.2%, respectively. Additionally, a comparative study of five insulative materials highlights polyurethane (Po) as the top performer, with a heat transfer performance of 14.3%, followed by feather fiber (Fe) (18.7%), fly ash (Fl) (19.8%), fiberglass (Fi) (21.9%), and coconut fiber (Co) (25.9%). Notably, net present value (NPV) of $689.336 and $448.01 was obtained for economic analysis of the current model over the existing model, showing the feasibility of the study. Hence, the cooler's effectiveness in storing vaccines in isolated regions exceeds that of conventional models, providing a hopeful solution to tackle vital challenges in vaccine distribution and preservation. [ABSTRACT FROM AUTHOR]

Structural dynamic properties like frequencies and mode shapes have been widely adopted for bridge condition assessment and damage identification. One of the main challenges lies in environmental factors, particularly the varying temperature, which significantly influences the bridge’s natural frequencies. In some cases, the effect of temperature changes can be comparable to, or even exceed, the effect caused by damage, rendering the damage identification methods ineffective. This study investigates the influence of the cross-sectional non-uniform temperature distribution, as a result of surrounding environmental factors, on the frequency of concrete girder bridges. A theoretical analysis is conducted to derive the bridge’s frequencies considering the cross-sectional non-uniform temperature distribution. The upper and lower bounds of the frequencies are developed by using only the environmental temperature and the largest temperature gradient defined by codes. More importantly, the damage to the bridge can be detected if the frequencies exceed the bounds for a certain period. This approach is convenient and practical in real applications without embedding thermocouples in the main girder. Numerical simulations, laboratory experimental tests, and field measurements are carried out to validate the derived frequency considering the cross-sectional non-uniform temperature distribution as well as the upper and lower bounds of the frequency. In particular, the results of the Z24 bridge show that when the bridge is damaged, the measured frequency exceeds the bound continuously, verifying the capability of the developed upper and lower bounds to evaluate bridge conditions. [ABSTRACT FROM AUTHOR]

This study suggests a combustion strategy and introduces a new geometry for the combustor of a micro gas turbine fed by ammonia as fuel. Ammonia is essential for making the energy supply chain more eco-friendly because it is seen as an excellent way to transport green hydrogen and as a renewable, carbon-free fuel. This study has considered different cases with a wide range of overall and primary equivalence ratios to find the optimum geometry regarding lower NO X emission, lower unburned NH 3 , lower unburned H 2 , and temperature distribution. A comprehensive case study of CFD simulation was conducted considering earlier research that showed the NO reduction level in an NH 3 -air swirl burner is dependent on the equivalence ratio of the primary combustion zone. The CFD simulation's boundary conditions were set by running a one-dimensional cycle simulation of the micro gas turbine at various loads. Results indicate that by modifying the geometry to include a staged rich-lean strategy with a primary equivalence ratio of 1.07, the NO mole fraction in the combustor can be reduced to one-third of its original level despite the significantly higher Combustor Inlet Temperature (CIT) compared to previous studies. The study found that the unburnt NH 3 and H 2 levels are low enough in the modified design, which shows the fuel is completely consumed and the overall combustion efficiency is optimized. Also, the analysis of the fluid dynamic behavior of the combustor shows that streamlines are uniform, leading to improved heat transfer and better overall system performance. These findings highlight the staged rich-lean strategy's potential by tuning the combustion stages' equivalence ratio as a promising approach to mitigate NO X emissions in ammonia combustion systems while maintaining high energy efficiency. • Study of ammonia combustion in a 3 kWe MGT's combustor. • Proposing a novel design approach for the combustor. • Higher combustor inlet temperature investigation in smaller combustor. • Implementation of a staged rich-lean combustion strategy to reduce NOx emissions by one-third. • Investigation of various primary ERs and identification of the optimal value at 1.07. [ABSTRACT FROM AUTHOR]

This research leads to carrying out the productivity and the efficiency of the carbon nanotubes (CNTs) that have extensive applications in solar collectors. Due to the superior thermal as well as electrical properties, the use of CNTs has an important contribution to the nanotechnology revolution. Therefore, owing to the aforementioned vital points, this investigation intended to put forth the thermophysical properties of both single and multi-walled CNT nanofluids past a stretching surface. Additionally, an electrically conducting nanofluid flow phenomenon enriches due to the inclusion of dissipation (Ohmic heating) and external heat source/sink. The dimensional form of the three-dimensional fluid flow phenomena is transformed to a non-dimensional form with the use of similarity transformation and further numerical procedure is implemented to solve the nonlinear governing equations. The substantial significance of the characterizing parameters is presented briefly via figures and the comparative analysis with the earlier investigation is deployed through the table. However, the main findings of this study are as follows: A significant attenuation in the shear rate is marked for the enhanced inertial drag but it augments for the augmented values of the magnetization; further, particle concentrations of both the CNTs favor accelerating the fluid momentum as well as temperature distribution. [ABSTRACT FROM AUTHOR]

Apples are preserved in cold storage within standard size crates to avoid injury during handling and are stacked in a specific manner to promote adequate air circulation. This research builds an air flow and heat transfer model of a cold room (5.75 m × 3.83 m × 3.75 m) with apple filled crates (0.55 m × 0.37 m × 0.3 m) modeled as a porous media and uses CFD simulation to study how alternate stacking impacts airflow distribution and product temperature. The conventional arrangement of crates, termed CS1, was simulated, and the resulting temperature distribution data were used to validate the model with published experimental data, a root mean square error of 1.13 °C indicates good match. The model is extended to examine temperature distribution for two additional arrangements of crates (CS2 and CS3) with changed orientations and spacing, in accordance with a specific strategy. CS3, featuring larger spacing along the z-direction, showed higher average air velocity compared to CS2 and CS1 by 7.4% and 3.7% respectively. CS3 also improved cooling rate by 25.2% and increased the number of chilled crates by 20% within 40 h, along with a reduced temperature heterogeneity (3.59 °C). The model could predict hot spots in various stacking configurations, aiding in optimal arrangement. [ABSTRACT FROM AUTHOR]

Due to the unique structures and superior chemical and physical properties, onion carbon holds great appeal for various applications, such as lubrication, energy storage and catalysis. However, conventional synthesis methods for onion carbon are often complex, resulting in products of low purity and quantity. Here we report the one-step combustion synthesis of onion carbon with high purity and tunable particle size by employing naphthalene as the precursor, and investigated the effect of combustion temperatures on the formation mechanism of onion carbon, leading to the achievement of controlled preparation of onion carbon. The size of synthesized onion carbon particles ranges from 50 to 190 nm, which increases with the synthesis temperature and shows a wider distribution at higher temperatures. Owing to the abundant oxygen-containing functional groups, as-synthesized onion carbon exhibits prolonged stability and solubility in organic solvents such as ethanol and glycerol. Furthermore, we tested the friction performance of stainless steel coated with onion carbon films by ball-on-disk mode on the upper surface with different loads and sliding speeds. Deposited onion carbon film improved the friction performance of stainless steel at high load and sliding speed. [Display omitted] [ABSTRACT FROM AUTHOR]

Hydroforming is a modern metal-forming process prominently used in the shipbuilding, aerospace, and automotive industries for forming lightweight, complex-shaped geometries due to their inherent process benefits. But this process faces challenges such as limited material selection, high tooling costs, and complex process control for obtaining a defect-free part with uniform thickness. Researchers are constantly innovating and advancing hydroforming technologies to overcome these limitations. This work reviews emerging tube and sheet hydroforming technologies, considering parametric effects and design considerations, particularly for micro-domain applications. Further, a wider acceptance of the hydroforming process in different industries is explored by discussing the studies that tried to improve the efficiency and quality of the hydroforming process. This study observed that better formability could be achieved in hydroforming with appropriate intermediate heat treatment, proper lubrication, the correct design of loading paths, and temperature distribution. In tube hydroforming, wrinkles, necking, and cracking observed to be largely reduced by properly selecting the internal pressure and feeding. The precise protrusion height and uniform thickness at different joint cross-sections in tube forming are found to be significantly influenced by the strain-hardening exponent, loading path, and friction coefficient. Electrohydraulic forming is found being increasingly used due to its higher productivity and lower product cost. However, further research is required to achieve complex sheet geometries with sharp corners. This research emphasizes that advanced research, artificial intelligence integration, and the exploration of alternative materials can improve the performance of the hydroforming process. [ABSTRACT FROM AUTHOR]

The article examines the risk, attributable fraction, and attributable number of cause-specific heat-related emergency hospital admissions in Switzerland from 1998 to 2019. It includes figures showing lag-specific risk ratios, exposure-response functions by age and gender, and sensitivity analyses for different temperature variables. Additionally, a table lists weather stations used in the study by canton, detailing median, minimum, and maximum daily maximum temperatures. [Extracted from the article]

Fire is a sporadic disaster of concrete bridges, with diverse fire environments and complex damage mechanisms. Accurately evaluating the damage situation of concrete bridges after a fire is exceedingly challenging. This study formulates a damage analysis and assessment method based on the step-by-step and progressively deepening working principle. The method relies on fire scene numerical reconstruction and encompasses key technical aspects, including bridge detection and analysis during the fire incident, fire scene numerical reconstruction, and subsequent bridge damage assessment. Building upon these principles, the study utilizes results from the detection and analysis of the concrete T-girder bridge during a fire incident to establish Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) models for the numerical reconstruction of the fire scene. These models enable the calculation of varying temperature distributions and the evolution of the bridge under fire. Compared with the parameters obtained through the ISO834 method, the numerical reconstruction approaches not only enhances the accuracy of replicating the bridge combustion process but also enables the extraction of temperature field distribution patterns within the bridge fire space and its concrete components. [ABSTRACT FROM AUTHOR]

AbstractThis study examines the thermo-mechanical behavior of auxetic metamaterial beams enhanced by graphene origami (GOri) under spatially varying nonuniform temperature distributions (SVTD). Utilizing Timoshenko beam theory considering von-Kármánn type nonlinear strain–displacement relationship, GOri beams are modeled as layered structures. The Ritz method is employed to solve equilibrium equations, analyzing the impact of GOri distribution patterns, content, and folding degree on post-buckling and vibration paths. The effects of five SVTDs, three end conditions, and three GOri distribution patterns on buckling, post-buckling behavior, and nonlinear free vibration characteristics are explored. Findings reveal that the parabolic temperature distribution with peak temperatures at beam ends (P-MAE) results in higher critical temperatures and nonlinear free vibration frequencies. This research provides crucial insights into the design and optimization of GOri-enabled metamaterial structures in complex thermal environments, highlighting the significant influence of nonuniform temperature distributions along the beam’s length. [ABSTRACT FROM AUTHOR]

In this paper, a nodal detection method for the detection and optimization of barrel helix offsets is proposed. The barrel used in this experiment is a 6-helix barrel. Moreover, the special properties of the film of Polyetheretherketone (PEEK) material are used to cover the surface of the barrel helix with a virtual in-mold decoration (IMD) film, and the unique nature of the film die offset in the IMD is utilized to detect the position of the barrel helix. The area with a large die index is the area with a large helix offset in the barrel, and the IMD die index is introduced to quantify the data. The IMD die index is used to determine the helix offset of the damaged barrel. The novelty of this work is that each node can use the die index to efficiently detect the position of the barrel helix deviation, carry out subsequent optimization and repair work through the optimization of the injection molding parameters and the design optimization of the barrel and verify the experiment by comparing the results. Through the steady-state simulation research mode, different permutations and combinations of the two process parameters are simulated to study their effects. Quantitative reference indicators include but are not limited to dependent variables such as the fluid flow velocity, shear rate, temperature distribution and phase transition, and the shear heating process of the injection screw is taken into account in the mold flow analysis to ensure that the die index value is more accurate. It can be seen from the analysis results that the temperature of the barrel changes after the groove depth and groove width are changed, and the effect ratio of the groove depth is lower than that of the groove width in the same degree of size change. [ABSTRACT FROM AUTHOR]

Purpose: The major limitation of tumor microwave ablation (MWA) operation is the lack of predictability of the ablation zone before surgery. Operators rely on their individual experience to select a treatment plan, which is prone to either inadequate or excessive ablation. This paper aims to establish an ablation prediction model that guides MWA tumor surgical planning. Methods: An MWA process was first simulated by incorporating electromagnetic radiation equations, thermal equations, and optimized biological tissue parameters (dynamic dielectric and thermophysical parameters). The temperature distributions (the short/long diameters, and the total volume of the ablation zone) were then generated and verified by 60 cases ex vivo porcine liver experiments. Subsequently, a series of data were obtained from the simulated temperature distributions and to further fit the novel ablation coagulated area prediction model (ACAPM), thus rendering the ablation-dose table for the guiding surgical plan. The MWA clinical patient data and clinical devices suggested data were used to validate the accuracy and practicability of the established predicted model. Results: The 60 cases ex vivo porcine liver experiments demonstrated the accuracy of the simulated temperature distributions. Compared to traditional simulation methods, our approach reduces the long-diameter error of the ablation zone from 1.1cm to 0.29cm, achieving a 74% reduction in error. Further, the clinical data including the patients’ operation results and devices provided values were consistent well with our predicated data, indicating the great potential of ACAPM to assist preoperative planning. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell (SOFC) has attracted wide attention because its efficiency is not limited by the efficiency of Carnot cycle. The structure of flow channel in SOFC has great effects on the internal mass distribution, which influences current density. In this paper, the height of flow channel and the position, arrangement, number and height of the fin which is placed in channel, are changed to get different structures of bi-layer interconnector, and they are applied to three layers SOFC stack. The effects of each structural parameter on the current density are studied by numerical simulation. The results show that, increasing the number of fins and bi-layer interconnector height can make more reactant gas enters the electrode. In addition, compared with the conventional structure, the current density can be increased by the bi-layer interconnector up to 31.256%, and the bi-layer interconnector structure could save n-1 layers of interconnector, which reduces the volume of SOFC stack. Among the five structural parameters, the position of fins has the least influence on temperature distribution and current density, while the arrangement of fins has the highest influence on volume current density, reaching 30%. Using a staggered arrangement and higher bi-layer interconnector can also improve the temperature distribution. • A three-dimensional SOFC stack with bi-layer interconnector was established. • Changing geometry of fins and channel height to get different structures. • Increasing number of fins and channel height improve concentration distribution. • The arrangement of fins has the greatest impact on current density. • Staggered fins and higher bi-layer interconnector reduce the highest temperature. [ABSTRACT FROM AUTHOR]

The composite catalyst improved the combustion performance by combining the advantages of multiple catalysts. In this paper, a high-efficiency methane catalytic combustion burner was designed for hydrogen production. The spinel of CoX 2 O 4 (X = Al, Fe, Cr, Cu) was prepared to composite with hexaaluminate. And the effects of temperature distribution and gas production were investigated under different operating conditions for these catalysts. The results indicated that the single-metal Mn catalyst facilitated the dry reforming reaction to produce more syngas. In addition, the hydrogen mole fraction first increased and then decreased with the increasing of Mn substitution, which achieved the maximum value of 12.6% at the Mn substitution of 3. Compared with the single catalyst, the synergistic effect of the bimetals reduced the activation energy of the methane reaction. And the Mn and Fe bimetal-substituted had excellent hydrogen production properties. However, the interaction between Co and Mn ions was not conducive to the doped dispersion of the catalyst and inhibited the catalytic activity. Meanwhile, higher inlet velocity and equivalence ratio increased the combustion temperature and syngas production. • Hexaaluminate and spinel catalysts were combined to enhance the catalytic performance. • Increasing the substitution ratio weakened the redox effect of hexaaluminate. • Bimetal-substituted hexaaluminate significantly reduced the preheating time. • CoCr 2 O 4 exhibited the highest Co3+/(Co3++Co2+) ratio and greatly activated methane. [ABSTRACT FROM AUTHOR]

A thorough understanding of the reactor core thermal hydraulic behavior is essential for the design and safety analysis of Sodium-cooled Fast Reactors (SFR). Due to the application of hexagonal subassembly, the core thermal hydraulic behavior is significantly affected by the flow field within the subassemblies, the inter-wrapper region and the hot pool. Analysis of the core thermal hydraulic behavior requires a model coupling the three regions mentioned above, which has been identified as one of the thermal hydraulic challenges in SFR. In the present study, a 3D model that covers the three regions was developed for the core of the China Experimental Fast Reactor (CEFR) with the Computational Fluid Dynamic (CFD) code, Fluent. The inter-wrapper region and the hot pool were modeled in detail, while the subassemblies were modeled with a special porous medium model. The core thermal hydraulics behavior under steady state was studied, more specifically, information for the flow field distribution at the core outlet, the inter-wrapper flow and the duct wall temperature distribution was obtained. Under steady state, liquid sodium in the inter-wrapper region is supplied by the inner region of the hot pool. And it enters the inter-wrapper region from the core outer region and returns back to the hot pool inner region from the core central region. The inter-wrapper flow is cooled by non-fuel subassemblies and heated up by fuel subassemblies. For non-fuel subassembly, the ratio of the total heat transfer rate between the inter-wrapper flow and the subassemblies to the heat generated within subassemblies could reaches 96%; for fuel subassemblies, the maximum ratio of the total heat transfer rate between the inter-wrapper flow and the subassemblies to the heat generated within subassemblies is 2.45%. Significant temperature gradients have been observed on the duct wall, with maximum values of 156.69 K/m in the vertical direction and 2,196.00 K/m in the circumferential direction. The largest temperature gradient appears on the duct of subassemblies adjacent to the transition region of fuel subassemblies and non-fuel subassemblies. [ABSTRACT FROM AUTHOR]

Severe friction on wheel/rail contact interface in the process of a train emergency braking can cause significant thermal and mechanical phenomena. Obvious friction heat and serious material damage will appear on the contact surface. In this article, the variation law of temperature and surface damage during a wheel sliding contact process are investigated. To achieve the research objective, a three-dimensional (3D) thermo-mechanical coupling contact finite element model (FEM) is established, and the temperature-dependent material parameters are used. The FEM is adopted to analyze the temperature distribution law on the contact surface. At the same time, a sliding contact testing machine is used to study the damage of materials in the contact area during the sliding contact. The study results indicate, the highest temperature of wheel and rail material is respectively 1014 ℃ and 461.8 ℃ during sliding contact. High temperatures are located at the subsurface and surface areas of contact region. When the distance to contact surface exceeds 1.4 mm, the temperature changes slightly. The types of damage on wheel surface are grooves and material peeling, while the flaky spalling, corrosive pitting, adhesion and grooves appear on the rail surface. Meanwhile, many cracks can be found on the contact surface, which is a major factor leading to material damage. The research results of this article are of great significance for understanding the thermal and mechanical damage of wheel/rail materials. [ABSTRACT FROM AUTHOR]

Simple Summary: Maintaining the optimal temperature in broiler houses, where chickens are raised, is crucial for their health and productivity. However, efficiently managing indoor temperatures is challenging due to the large size of these facilities and varying weather conditions. This study developed and tested a computer model that predicts changes in air temperature inside a broiler house when ventilation systems are adjusted. The model accurately simulated how air movement affects indoor temperatures based on the number of fans operating or stopped. It also accounted for the heat produced by the chickens. The results also showed that adjusting the openings of air inlets can help reduce high temperatures but this can sometimes make the ventilation system less efficient or lead to an uneven temperature distribution. This study confirmed that this approach effectively improves ventilation strategies by comparing the model's predictions with real-life data from broiler houses. This model can assist farmers and engineers in designing better ventilation systems, ensuring better conditions for chickens. Improved conditions will lead to more efficient poultry production, benefiting both the industry and consumers. Maintaining the optimal microclimate in broiler houses is crucial for bird productivity, yet enabling efficient temperature control remains a significant challenge. This study developed and validated a computational fluid dynamics (CFD) model to predict temporal changes in indoor air temperature in response to variable ventilation operations in a commercial broiler house. The model accurately simulated air velocity and airflow distribution for different numbers of tunnel fans in operation, with air-velocity errors ranging from −0.22 to 0.32 m s−1. The predicted airflow rates through inlets and cooling pads showed good agreement with measured values with an accuracy of up to 108.1%. Additionally, the CFD model effectively predicted temperature dynamics, accounting for chicken heat production and ventilation effect. The model successfully predicted the longitudinal temperature gradients and their variations during ventilation cycles, validating its reliability through comparison with experimental data. This study also explored different variable inlet configurations to mitigate the temperature gradient. The variable inlet adjustment showed the potential to relieve the high temperatures but may reduce overall ventilation efficiency or intensify temperature gradients, which confirms the importance of optimising ventilation strategies. This CFD model provides a valuable tool for evaluating and improving ventilation systems and contributes to enhanced indoor microclimates and productivity in poultry houses. [ABSTRACT FROM AUTHOR]