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Fused filament fabrication (FFF) is a widely used processing method; however, heat transfer limitations within a conventional nozzle result in relatively low flow rates, leading to lengthy production times, compared to traditional processing methods, ultimately restricting its industrial application. Recently, a novel rotational nozzle FFF three-dimensional (3 D) printer has been patented and developed to enhance processing efficiency. Despite this achievement, the fundamental mechanisms behind this novel process remain unclear. In this study, both analytical analysis and numerical simulations were conducted based on a force-controlled scaled-down experimental setup. This setup, designed according to the pressure-induced melt removal theory, provided melt throughput data under varying heater temperatures, extrusion forces, and rotational speeds. Agreement between the modeling and experimental results confirms the generalizability of the models. Modeling predictions of temperature and velocity distributions indicate that viscous dissipation affects the average temperature and filament velocity. To simulate the real-world working conditions of FFF 3 D printing, a velocity-controlled simulation was introduced. It was observed that the average melt film thickness increases with nozzle rotational speed due to viscous dissipation. Additionally, the extrusion force required for the same printing speed decreases with increasing nozzle rotational speed, primarily due to the higher shear rate reducing melt viscosity. [ABSTRACT FROM AUTHOR]

In this work, we numerically investigate how a nonuniform magnetic field affects the flow and heat transfer in a bottom-heated closed enclosure filled with a thermosensitive ferrofluid. Under the simultaneous action of the gravitational and external magnetic field, a complex flow develops inside the cavity. We change the intensity of the external magnetic field aiming to understand how the flow field, temperature distribution, and net heat transfer are affected. Our findings reveal that the magnetic field has a significant influence on the topology of the flow and temperature fields, consequently impacting the overall heat transfer. It is possible to use the magnetic field generated by a conducting wire to change the net heat transfer through the cavity. We found that the average Nusselt number is a growing function of the magnetic field intensity, except for a specific Rayleigh number. Furthermore, we recognize non-stationary regimes at intermediate magnetic Rayleigh numbers, associated with unstable topological transitions in the flow pattern induced by the magnetic field. Consequently, we uncover flow regimes characterized by steady boundary conditions but exhibiting periodic flow and heat transfer patterns. Additionally, we observe that the unsteady topological transitions are suppressed by high magnetic Rayleigh numbers, resulting in steady flow. [ABSTRACT FROM AUTHOR]

In this work, the influence of evaporative flux over the atomization driven by surface acoustic waves (SAWs) of a Newtonian water drop is studied. The drop is placed on a heated substrate at constant temperature, higher than the saturation temperature at a given vapor pressure. In this manner, an interfacial temperature distribution arises along the drop free surface in terms evaporative mass flux and vapor recoil, which repercussion over aerosol size is studied by determining the asymptotic evolution equation governing the acoustically driven free surface. At such scenario, the connection between surface tension and temperature is also considered; thus, thermocapillary flow is incorporated into our drop model, described in terms of fundamental parameters, like the evaporation number, Marangoni number, and acoustic capillary number. Numerical solution of the evolution equation led us to obtain a simplified representation of the drop interfacial deformation mechanism, capable of predicting atomization and portraying the influence of evaporation over atomization. Subsequent analysis shows that the incorporation of evaporation at SAW atomization traduces in normal stresses counteracting the acoustic and thermocapillary effect, leading to the development of smaller drop aspect ratios with respect to the no-evaporative case. Being aware that the aerosol size is deeply related to the aspect ratio, we propose an analytical expression to estimate aerosol diameter under evaporative conditions. The results show that aspect ratio reduction leads to a decrement on aerosol size, up to two orders of magnitude, with respect to the no-evaporative case. Our study is a first approach providing insight about the importance of evaporation on aerosol regulation at SAW atomization. [ABSTRACT FROM AUTHOR]

The SPARC tokamak will have scrape-off layer parallel heat fluxes on the order of GW/m2. Managing power exhaust of this magnitude will be mandatory for a reactor-scale device. To enable this mission, a thermal diagnostic suite will be deployed to measure the in-vessel structural temperatures to ensure they do not exceed their design limits and to determine the spatial distribution and magnitude of energy deposited onto the first wall. Thermocouples and fiber Bragg gratings have been selected for their environmental compatibility and proven useful on other fusion devices. High-density thermocouple arrays in the divertor will have two spring-loaded thermocouples per divertor target tile, which are being used as calorimeters, and will look to resolve the temperature distribution within the tile due to a swept or static strike point. All systems will need to survive the vacuum vessel bake, set at a minimum plasma facing surface temperature of 350 °C, which presents a particularly challenging environment for the fiber-based subsystem. Along with this temperature design requirement, all the materials in the primary vacuum need to be ultra-high vacuum compatible, able to handle the expected neutron and gamma radiation, as well as tritium exposure, all of which restrict material options. Finally, due to the expected activated environment in SPARC, there will be little chance to replace defective sensors, so system resilience is ensured through toroidal redundancy, probe material selection, and mitigating the impact of common-mode failures. Initial testing of sensors show that intershot structural measurements are sufficiently captured with the raw output, but intrashot measurements of the plasma facing material requires model-based interpretive tools. [ABSTRACT FROM AUTHOR]

Self-drilling micropiles (SDMs) are gaining popularity as bearing foundation elements, as this construction technique allows for considerable time and cost savings. However, the irregular geometry and variability in the bearing capacity present uncertainty and a significant risk that has limited SDM deployment. To date, no reliable technology has been used to measure the SDM geometry. This paper proposes a methodology that uses distributed fibre optics (DFO), heat conduction modelling and inverse analysis to measure the pile geometry, and could also be extended to assess its bearing capacity. The temperature distribution during cement hydration was measured using two DFO investigative technologies and was compared to traditional temperature measurements using point sensors. An inverse analysis of SDM geometry was subsequently carried out based on the DFO measurement of temperature, a finite-element heat conduction model and a calibration pile. Finally, the calculated pile geometry was compared to the geometry of an excavated pile in the uppermost part. The methodology presented here is not only intended as a tool for designing SDMs but can also be deployed as a structural health monitoring system to detect and monitor crack formation. [ABSTRACT FROM AUTHOR]

The term "thermal conductance" is used to describe a material's ability to transport or conduct heat. Materials with high thermal conductivity are employed as heating elements, while those with poor thermal conductivity are used for insulation purposes. It is known that the thermal conductivity of pure metals decreases as temperature increases. In this study, the primary focus is on the physical assessment of thermal conductivity, entropy, and the improvement rate of thermal density in a magnetic nanofluid. To achieve this, nonlinear partial differential equations are transformed into ordinary differential equations. These equations are further solved using a computational method known as the Keller box technique. Various flow parameters, such as the Eckert number, density parameter, magnetic-force parameter, thermophoretic number, buoyancy number, and Prandtl parameter, are examined for their impact on velocity, temperature distribution, and concentration distribution. For the asymptotic results, the appropriate range of parameters, such as 1.0 ≤ ξ ≤ 5.0, 0.0 ≤ n ≤ 0.9, 0.1 ≤ Ec ≤ 2.0, 0.7 ≤ Pr ≤ 7.0, 0.1 ≤ Nt ≤ 0.5, and 0.1 ≤ Nb ≤ 0.9, is utilized. The key findings of this study are related to the assessment of heat transfer in a magnetic nanofluid considering thermal conductivity, entropy generation, and temperature density. It is observed that the temperature distribution increases as entropy generation increases. From a physical perspective, thermal conductivity acts as a facilitating factor in enhancing heat transfer. The study concludes by emphasizing the consistency achieved through a comparison of the latest findings with previously reported analyses. [ABSTRACT FROM AUTHOR]

Considering the unique soil structure and the temperature rise effect of seawater's electrical and thermal parameters, accurately simulating the grounding characteristics of marine DC grounding electrodes is the basis for ensuring the safe and stable operation of offshore wind power grid-connected DC projects. The paper proposes a dynamic finite element model of ocean grounding electrode characteristics based on the coupling of circuits and electrical–thermal fields. In the finite element model, soil parameters can be controlled by the time-varying temperature distribution, and the dynamic process of the coupling of soil electrical and thermal fields in the process of direct flow can be accurately simulated. A time-varying equivalent circuit model for controlling the electric–thermal field can be implemented to accurately simulate the dynamic process of the shunt coefficient for each conductor segment in a composite DC grounding electrode with multiple injection points. The effectiveness is verified by comparing with the experimental data. Finally, the dynamic flow process, temperature rise process and their mutual influence are quantitatively analyzed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the sealing performance of different deep groove mechanical seals by considering the changing law of dynamic pressure effect and temperature gradient caused by high speed and high pressure. Design/methodology/approach: A thermohydrodynamic lubrication model (THD) of the mechanical seal was constructed and solved using the commercial software FLUENT. The pressure and temperature distributions of the fluid under different groove types, as well as the sealing performance under different pressures, rotational speeds and sealing gaps, are obtained. Findings: The annular groove (AG) can effectively reduce the temperature, and the T-type spiral groove (STG) can effectively inhibit the leakage. The increase of pressure and rotational speed leads to the enhancement of dynamic pressure effect and the increase of leakage, while the sealing gap increases and the leakage increases while taking away more heat. The choice of groove type is very important to the impact of sealing performance. Originality/value: In consideration of the beneficial effect of deep grooves on cooling performance, the viscous temperature equation and the impact of the thermodynamic lubrication model are evaluated in conjunction with the sealing performance of four distinct groove types. This approach provides a theoretical basis for the optimal design of mechanical seals. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0184/ [ABSTRACT FROM AUTHOR]

Coffee is a key agricultural product in national and international markets. Physiological parameters, such as plant growth indicators, can signal interruptions in these processes. This study aimed to characterize the temperature obtained by a thermal camera embedded in a remotely piloted aircraft (RPA) and evaluate its relationship with the water potential (WP) and stomatal conductance (gs) of an experimental coffee plantation using geostatistical techniques. The experiment was conducted at the Federal University of Lavras, Minas Gerais, Brazil. A rotary-wing RPA with an embedded thermal camera flew autonomously at a height of 10 m and speed of 10 m/s. Images were collected on 26 November 2019 (rainy season), and 11 August 2020 (dry season), between 9:30 am and 11:30 am. Data on gs and WP were collected in the field. The thermal images were processed using FLIR Tools 5.13, and temperature analysis and spatialization were undertaken using geostatistical tools and isocolor maps by Kriging interpolation in R 4.3.2 software. Field data were superimposed on final crop temperature maps using QuantumGIS version 3.10 software. The study found that with decreasing WP, stomatal closure and reduction in gs occurred, increasing the temperature due to water deficit. The temperature distribution maps identified areas of climatic variations indicating water deficit. [ABSTRACT FROM AUTHOR]

Non-uniform heating has been one of the major challenges using radio frequency (RF) treatment in continuous-flow pasteurization, enzyme inactivation, extraction, or applications for fluid/semi-fluid foods. The objective of this study was to design an auxiliary device for the continuous-flow treatment of fluid/semi-fluid samples in the Strayfield SO6B RF heating system produced in UK. This device was composed mainly of peristaltic pumps, an electromotor, a sample trough, and a control system. The sample trough was equipped with a set of cut and folded flight screws to realize the mixing and stirring of samples. Among them, the sample trough was connected with the feed tank by a peristaltic pump to realize continuous flow treatment. The control system was used to realize the opening and closing of the motor and peristaltic pump, as well as the temperature measurement of the outlet and inlet. The components of the device were placed between the RF electrode plates. Polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK) with low dielectric loss factor were selected to avoid significant absorption of RF energy from heating and distortion. The internal temperature distribution of the sample in the trough was determined using the multi-point temperature measurement platform. A temperature recorder was connected with 9 K-type thermocouples. Nine representative points were accurately measured in the three longitudinal sections in the sample trough. The heating uniformity index (λ) inside the sample was then calculated to evaluate the RF heating uniformity, according to the temperature values of the above 9 points. Three samples were selected for the continuous-flow RF treatment, including raw cow's milk, carboxymethylcellulose (CMC) solution, and apple pomace-citric acid mixed solution. The results showed that the heating rate of samples was ranked in the descending order of the raw cow's milk, CMC solution, and apple pomace-citric acid mixed solution, under the same RF heating conditions (electrode gap 140 mm). All three samples reached the target temperature (70 °C) within 20 min. The device was well-assisted RF continuous and uniform heating of fluid/semi-fluid samples with different properties. The samples were performed on the RF heating with or without screw agitation under stationary conditions. Screw agitation was improved the RF heating uniformity of all samples. Among them, the average λ value of 9 points was reduced from 0.139 to 0.068 in the CMC solution, indicating a more significant performance. Furthermore, the CMC solution and apple pomace-citric acid mixed solution (PS5) were utilized with the lower heating uniformity in the continuous-flow RF treatment mode. In the absence of screw agitation, the temperature of the upper layer was significantly higher than that of the middle and lower layers for both samples, especially in the upper layer near the outlet. The edge/corners overheating was then attributed to the electromagnetic field deflection and accumulation. Screw agitation also significantly improved the heating uniformity of two samples under flowing conditions. The maximum difference in temperature decreased by 13.4 and 11.4 °C, respectively. While the floating of solid particles in the solid-liquid mixed samples reduced the heating uniformity at the lower stirring speeds. Overall, this device can be expected to realize the continuous and uniform RF treatment of fluid/semi-fluid samples. The finding can provide technical and theoretical support to the RF continuous heating and industrialized treatment. [ABSTRACT FROM AUTHOR]

Tracer based planar laser-induced fluorescence (PLIF) has emerged as a powerful in-situ measurement technique with a considerable spatial and temporal resolution for Internal combustion (IC) engines. In PLIF, the emitted fluorescence signals from a tracer molecule are processed to determine distribution of temperature, fuel, residual gases, etc. However, it is imperative to have a thorough understanding of the tracer physical properties and its fluorescence intensity dependencies on excitation wavelength, pressure, temperature and bath gas composition existing inside the combustor for accurate quantitative interpretation. This work consists of a series of two articles providing a detailed review of the existing literature of fluorescence characteristics of various molecules used as tracers in IC engine applications. Due to the overwhelming usage of organic compounds in IC engine environment, the work is restricted to them. Part A of this work is focussed on non-aromatic compounds whereas part B will focus on aromatics (toluene, anisole, naphthalene, 1-methylnaphthalene and fluoranthene). Due to a large energy gap between the excited singlet and triplet states of aromatics, they are highly sensitive to oxygen quenching effects than ketones. Absorption cross-section might increase or decrease with temperature but is insensitive to pressure changes. Fluorescence quantum yield of aromatics show a very strong reduction with increase in temperature but might either increase or decrease with increasing pressure. The pressure sensitivity is found to increase with the number of atoms in a bath gas molecule. Fluorescence spectra are found to undergo redshift with temperature which can be used to measure temperature using 2 colour thermometry. The large fluorescence quenching by oxygen can also be used to directly measure fuel–air ratio using FARLIF methodology. Towards the end several IC engine studies are reviewed to discuss various aspects of mixture formation and temperature distribution. [ABSTRACT FROM AUTHOR]

In this study, a three-dimensional thermal analysis of the laser sintering additive manufacturing process was conducted. Analytical heat sink methods and numerical finite element analysis in Abaqus software were employed to assess the thermal behavior of the workpiece. Comparing the analytical method used in this study with those in the existing literature reveals the superiority of the results obtained in this research. Additionally, it has been demonstrated that the numerical and analytical results in this study are in good agreement with each other. Furthermore, the proposed method in this study has yielded significant findings, indicating its applicability in addressing the complexity of the problem. The findings demonstrated that optimizing the temperature distribution is attainable through adjustments to the initial workpiece temperature and scanning speed. [ABSTRACT FROM AUTHOR]

The rapid acceleration of urbanization has a serious impact on the urban ecological environment. It is of great importance to carry out numerical simulation research on urban spatial thermal environment for improving urban ecological environment. At present, there are few studies on the influence and accuracy evaluation of different vegetation settings in computational fluid dynamics (CFD) on the simulation results. Aiming to quantify impacts of vegetation changes and vegetation model settings on the numerical simulation of urban three-dimensional thermal environment, this study 1) based on Gaofen-2 remote sensing data and CFD model, the wind and heat environment at the block scale was simulated and analysed; 2) The vegetation model is assumed to be three models including cold source, constant temperature wall, and porous medium. Based on the heat transfer and cooling mechanism of vegetation, these three different vegetation models and their related CFD parameter settings are used to simulate the 3D spatial thermal environment. The research results show that the distribution of temperature has a great correlation with the direction of wind. The temperature distribution at different heights at night did not show significant differences. Due to the obvious convective heat transfer between the building surface and the atmosphere, the temperature in the upwind direction is significantly lower than that in the downwind direction. At a height of 2 m and below, setting the vegetation as the wall model has the best performance, and at a height above 5 m, the results of the wind and heat environment of the three setting methods are basically similar. The wind environment results of the same vegetation setting are different at different heights. [ABSTRACT FROM AUTHOR]

UAV thermal infrared remote sensing technology, with its high flexibility and high temporal and spatial resolution, is crucial for understanding surface microthermal environments. Despite DJI Drones' industry-leading position, the JPG format of their thermal images limits direct image stitching and further analysis, hindering their broad application. To address this, a format conversion system, ThermoSwitcher, was developed for DJI thermal JPG images, and this system was applied to surface microthermal environment analysis, taking two regions with various local zones in Nanjing as the research area. The results showed that ThermoSwitcher can quickly and losslessly convert thermal JPG images to the Geotiff format, which is further convenient for producing image mosaics and for local temperature extraction. The results also indicated significant heterogeneity in the study area's temperature distribution, with high temperatures concentrated on sunlit artificial surfaces, and low temperatures corresponding to building shadows, dense vegetation, and water areas. The temperature distribution and change rates in different local zones were significantly influenced by surface cover type, material thermal properties, vegetation coverage, and building layout. Higher temperature change rates were observed in high-rise building and subway station areas, while lower rates were noted in water and vegetation-covered areas. Additionally, comparing the temperature distribution before and after image stitching revealed that the stitching process affected the temperature uniformity to some extent. The described format conversion system significantly enhances preprocessing efficiency, promoting advancements in drone remote sensing and refined surface microthermal environment research. [ABSTRACT FROM AUTHOR]

This research experimentally demonstrates the practicability of using large-sized direct solar frying as an alternative technology for the predominantly biomass-based injera baking method. The system was designed and developed with fryers 40, 50, and 55 cm in diameter and two operational options: continuous mode and alternating mode. Extensive experimental testing was conducted on each prototype to demonstrate solar frying and determine the relative performance. The findings indicate that the 2 kW heating capacity of the 40 cm-sized solar fryer model conducted baking processes at a relatively lower system temperature in both application modes compared to the larger-sized fryers. As a result, this system maintained a consistent average fryer temperature distribution and shorter initial heating time, without the requirement of a reheating process during the subsequent baking cycles. The experimental testing also demonstrated that alternating-mode applications were more practical for the 40 cm-sized fryers than for the larger ones. Overall, direct solar frying is more efficient and convenient for the 40 cm-sized solar fryers. In contrast, the larger-sized systems required a larger fryer thermal storage capacity coupled with larger-size solar concentrators to maintain equivalent stable operational conditions, conversely leading to a lack of application simplicity and higher system costs. [ABSTRACT FROM AUTHOR]

Harmonics in the power grid contribute to increased power losses in both the core and windings of power transformers. These losses lead to abnormal rises in temperature causing overheating and reduce the efficiency of the transformer. If the losses and temperature exceed the values set during the design stage for linear load conditions, it can damage the transformer's insulating materials and shorten its lifespan. To assess the thermal impact of power system harmonics on transformers under steady-state and transient conditions, the rated losses and harmonic losses of the transformer are calculated. These losses are then inputted into a developed thermal 3D finite element method (FEM) performance model to determine the temperature distribution of transformer components. The numerical results from the thermal model will be compared with data from a Hyundai test report and real measurements from Egypt's Kureimat power plant, specifically a 750 MW combined cycle power plant. The thermal modeling is focused on a step-up (16.5/240 kV), 240 ± 4 × 2.5%, 180/240/300 MVA power transformer operating in ONAN, ONAF1, and ONAF2 modes. This paper shows that the developed model aligns closely with actual measurements and the HYUNDAI test report. The loss calculations reveal that the discrepancy in total losses, with and without accounting for harmonics, becomes more pronounced as the load increases. Using this model, the presence of grid harmonics results in a higher temperature distribution across transformer components, leading to an increase in the hot spot temperature. [ABSTRACT FROM AUTHOR]

Based on a physical water model with a scaling factor of 0.5 and a coupled flow–heat transfer–solidification numerical model, this study investigates the influence of the submerged entry nozzle (SEN) depth on the mold surface behavior, slag entrapment, internal flow field, temperature distribution, and initial solidification behavior in slab casting. The results indicate that when the SEN depth is too shallow (80 mm), the slag layer on the narrow face is thin, leading to slag entrapment. Within a certain range of SEN depths (less than 170 mm), increasing the SEN depth reduces the impact on the mold walls, shortening the "plateau period" of stagnated growth on the narrow face shell. This allows the upper recirculation flow to develop more fully, resulting in an increase in the surface flow velocity and an expansion in the high-temperature region near the meniscus, which promotes uniform slag melting but also heightens the risk of slag entrainment due to shear stress at the liquid surface (with 110 mm being the most stable condition). As the SEN depth continues to increase, the surface flow velocity gradually decreases, and the maximum fluctuation in the liquid surface diminishes, while the full development of the upper recirculation zone leads to a higher and more uniform meniscus temperature. This suggests that in practical production, it is advisable to avoid this critical SEN depth. Instead, the immersion depth should be controlled at a slightly shallower position (around 110 mm) or a deeper position (around 190 mm). [ABSTRACT FROM AUTHOR]

BACKGROUND: Early blight is one of the main diseases that causes serious pepper yield and quality reduction. The identification of the presymptomatic features during the incubation period is of great research significance, in that scientific prevention measures in the incubation period may effectively reduce the loss of peppers. RESULTS: The present study confirms the feasibility of the identification of presymptomatic features in pepper early blight by infrared thermography during the incubation period. The infrared thermal images of pepper blades were captured during the whole incubation period in our experiment. Evaluation parameters such as temperature uniformity (U) and the variation coefficient (C) were established by infrared thermal images for the blade temperature field. Evaluation parameters such as temperature uniformity U and variation coefficient C of pepper blades change during the time from being inoculated to significant morbidity. For cases of stabbing inoculation, there were no relatively obvious symptoms in visible light images until 96 h after inoculation, whereas some presymptomatic features appeared in infrared thermal images at 60 h after inoculation. Based on the uniformity changes (δU) and the variation coefficient changes (δC) in the temperature field distribution, the characteristic polynomial (CP)‐GBDT model has been established by optimizing the gradient boosting decision tree (GBDT) model. Compared with the GBDT mode, the CP‐GBDT model accuracy increased from 87.5% to 91.7% on the test set. CONCLUSION: Evaluation parameters such as temperature uniformity U and variation coefficient C can be used to effectively characterize the presymptomatic features of pepper early blight by infrared thermography during the incubation period. The results of the present study can provide a reference for the detection of crop diseases in the incubation period. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The variation of temperature fields during the winding process of CFRP (Carbon Fiber Reinforced Polymer) due to fiber winding is a key factor influencing its curing and shaping. Traditional heating methods result in energy wastage and environmental pollution during the heating process. Electromagnetic induction technology, as a non-contact, pollution-free, and efficient heating method, is playing an increasingly significant role in the process of heating and curing CFRP. This study focuses on two heating methods, internal and external, for CFRP wound circular tubes. It establishes finite element analysis models for induction heating with different coil structures. The heating mechanisms of different coil-induced CFRP wound circular tube models are explained, and the effects of external arc-shaped coils and external/internal annular coils on the temperature field distribution of CFRP wound circular tubes are investigated. By comparing simulations with experiments, the correctness of the numerical analysis model in this study is demonstrated. It offers viable heating methods for different conditions in industrial production, providing theoretical support and empirical data for the induction heating of CFRP wound circular tubes. [ABSTRACT FROM AUTHOR]

This study investigates the dynamic response of an infinite structure comprising two coaxial cylinders employing the one-relaxation-time generalized thermoelastic diffusion model. The inner cylinder, serving as a cavity, possessing a radius a, while the outer cylinder has radius b. The inner cylinder is insulated and experiencing a localized thermal load with thickness 2 h. The outer cylinder, with radius b, is also experiencing to a localized thermal load with width 2 h, and its surface exhibits no traction. Additionally, the structure experiences the influence of a solenoidal body force. The analysis of this problem employs a combination of Laplace transform, inverse Laplace transform, and exponential Fourier transform techniques. Numerical analysis of the resulting solutions reveals the variations in temperature, displacement, radial stress, concentration, and potential fields as a function of the radial coordinate. Results indicate a minimal impact of the time interval on the temperature distribution, while displacement and radial stress exhibit significant time-dependent behavior. These findings highlight the significance of incorporating thermoelastic diffusion theory in the analysis of real-world engineering problems. [ABSTRACT FROM AUTHOR]

Given is a bounded domain Ω ⊂ ℝ n {\Omega\subset\mathbb{R}^{n}} , and a vector-valued function defined on ∂ ⁡ Ω {\partial\Omega} (depicting temperature distributions from different sources), our objective is to study the mathematical model of a physical problem of enclosing ∂ ⁡ Ω {\partial\Omega} with a specific volume of insulating material to reduce heat loss in a stationary scenario. Mathematically, this task involves identifying a vector-valued function 퐮 = ( u 1 , … , u m ) {\mathbf{u}=(u^{1},\dots,u^{m})} ( m ≥ 1 {m\geq 1} ) that represents the temperature within Ω and gives rise to a free boundary, somehow reminiscent of, but not equivalent to, the Bernoulli free boundary problem. [ABSTRACT FROM AUTHOR]

This paper investigates the fire resistance of extended end-late beam-column middle (EEBM) joints, taking into account the gradient temperature effect under postearthquake fire (PEF). First, finite element (FE) models of the EEBM joints were established based on mechanical models under different conditions, the accuracy of the models is validated by existing experiments. Next, the gradient temperature distribution, residual deformation and stress in the EEBM connections were analyzed. Finally, 125 FE models were established to conduct parameter analysis including the column flange width-thickness ratio (α), column web height-thickness ratio (η), beam flange-to-end plate thickness ratio (γ), beam flange width-thickness ratio (δ), beam web height-thickness ratio (β) and damage variables (D˜). The generalized failure point to determine the generalized ultimate displacement and a calculation method for the flexural capacity at high temperatures are proposed against the EEBM connections. The results demonstrate that the α , η , and γ have a significant impact on the failure modes of the EEBM connections. The generalized ultimate displacement of the EEBM connections is approximately 1/40 of the beam span. The α , γ , and D˜ dramatically affect the fire resistance of the EEBM connections. The weakening of the flexural capacity due to damage is greater than that due to high temperatures. The findings can provide basic data, theoretical reference, and technical support for the design and research of EEBM connections under PEF. Practical Applications: EEBM connections are widely used in multi-story steel frame and portal frame, etc. Postearthquake fire is common, which will cause significant casualties and economic losses. On account of the residual stress and deformation caused by earthquake in EEBM connections, it is impossible to accurately evaluate the reliability and safety of EEBM connections under postearthquake fire using the failure mechanism of EEBM connections under fire. Therefore, the findings of this study can provide valuable reference for design, reinforcement and repair of EEBM connections. [ABSTRACT FROM AUTHOR]

For small-sized structures or devices, size-dependent effect and thermal-induced deformation become the main concerns in guiding their practical applications. To reveal such concerns of porous structures, the dynamic response of a finite porous microrod, subjected to a moving heat source and fixed at both ends, is investigated based on the non-local elasticity theory and the theory for porous materials with thermal relaxation. The corresponding governing equations are formulated and solved using Laplace transform and its numerical inversion. The distributions of the non-dimensional temperature displacement stress and volume fraction are obtained and illustrated graphically. In the simulation, the effects of the non-local parameter, the velocity of the heat source, and the thermal lag factor on the considered quantities are examined and illustrated graphically. Comparisons between the microrod with voids and without voids are shown. [ABSTRACT FROM AUTHOR]

Thermal error is a critical factor influencing the machining accuracy of CNC machine tools, so it is essential to comprehensively model and compensate for thermal errors in CNC machine tools. This paper proposes a deep attentional residual network thermal error prediction model driven by thermal image inputs. In contrast to traditional models that solely rely on temperature data, the proposed model utilizes thermal image data as a key input parameter and incorporates temperature data from sensitive points to fully represent the machine's temperature distribution. Furthermore, the attention mechanism is used to optimize the hyperparameters and network structure of the residual network model. Transfer learning is employed to improve training efficiency, reduce data requirements, and enhance the model's transferability. The optimized model achieves a prediction accuracy of 99.5% and converges more quickly. Finally, thermal error compensation experiments are conducted on the platform of the Siemens 840D system with an average effect of more than 70%. The proposed thermal error compensation method is effective and provides a foundation for precision machining. [ABSTRACT FROM AUTHOR]

In this study, a new microwave infrared hot air rolling bed dryer (MIHRBD) was developed and computational fluid dynamics (CFD) techniques were introduced into the design process of the integrated drying system. The structure of the air distribution device was optimised to improve the airflow uniformity over the curved surface of the rolling bed in the microwave-hot air drying combined equipment. The research findings reveal that, across eleven models, the outlet airflow velocity stabilises once the number of mesh elements reaches 5 million, achieving significant computational accuracy at that point. Optimizing components like the uniform air distribution pipe, turbulence plates, and wind deflectors significantly enhanced airflow distribution uniformity by 52.1%. The best airflow and temperature distribution uniformity on the rolling bed surface was achieved when the inlet airflow velocity ranged from 1 to 3 m s−1, with minimum V d , U v and temperature non-uniformity coefficients of 0.007 m s−1, 7.2% and 0.2%, respectively. Validation tests on the MIHRBD pilot equipment showed that after optimizing the uniform air distribution device, the minimum temperature difference on the pleurotus eryngii surface was 3.1 °C. This confirmed the feasibility of the computational fluid dynamics method. Introducing hot air significantly enhanced pleurotus eryngii 's drying uniformity, with the Page model effectively predicting the MIHRBD drying process. This study provides technical support for future developments in this field of equipment manufacturing and drying process analysis. • A new microwave infrared hot air rolling bed dryer (MIHRBD) was developed. • Design of MIHRBD with advanced CFD for enhanced airflow uniformity. • Optimised uniform air distribution design increases airflow uniformity by 52.1%. • Colour quality of dried materials improved by optimised MIHRBD process. [ABSTRACT FROM AUTHOR]

Brain cells can be damaged by higher temperature in the brain, and brain temperature distribution monitoring system is required from the perspective of brain preservation. Brain tissue can be further damaged by direct measurement of temperature using some sensors. Therefore, indirect methods of measuring temperature are required. In this study, we propose a method for estimating the average metabolic rate of the entire brain based on the difference between the observed and estimated blood flow temperatures that can be measured during selective brain hypothermia. Our mathematical simulator can calculate the brain temperature distribution based on the estimated average metabolic rate, taking into account other parameters like heat transfer, metabolic heat of individual tissues, heat‐washout by blood flow, and environmental temperature. The algorithm for estimating the metabolic rate of mathematical master model substituted as a human head is confirmed using the mathematical slave model on the simulator. It is possible to present the temperature distribution by estimating metabolic heat production in the brain, considering the equilibrium between heat wash‐out by the blood flow and heat transfer. In addition, an appropriate initial value of brain temperature enables the accurate temperature management enough for clinical use even in the process of temperature estimation. The development of our proposed method will make it possible to construct a non‐invasive monitoring system that presents the estimated temperature distribution in the brain instead of the conventional invasive method. The new system is expected to be utilized in a various treatments related to some brain disorders. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The present study is concerned with the analysis of unsteady heat conduction in regular bodies (large plane wall, long cylinder, and sphere) with constant initial temperature, prescribed surface heat flux and thermal properties of the solid that are invariant with temperature. Surprisingly, this important topic is absent in textbooks on heat transfer. The exact evaluation of the dimensionless surface temperatures varying with the dimensionless time in the regular bodies over the entire dimensionless time domain 0 < τ < ∞ is carried out with a symbolic algebra code. Thereafter, regression analysis is applied to the data gathered for the dimensionless surface temperatures varying with the dimensionless time of the regular bodies inside the dimensionless "small time" time sub-domains 0 < τ ≤ τ th . The dimensionless threshold time τ th is a decisive parameter that establishes the borderline between the "small time" sub-domain τ → 0 and the "large time" sub-domain τ ≫ 0 comprising the entire dimensionless time domain 0 < τ < ∞. Based on regression analysis, compact asymptotes are constructed for the dimensionless surface temperatures varying with the dimensionless time inside the dimensionless "small time" sub-domain 0 < τ ≤ τ th . At the end, agreements with the dimensionless exact, analytical surface temperature distributions (the baseline solutions) valid for the dimensionless time sub-domain 0 < τ < ∞. are considered of excellent quality. [ABSTRACT FROM AUTHOR]

The thermal analysis of brake discs is crucial for studying issues such as wear and cracking. This paper establishes a symmetric two-dimensional brake disc model using the barycentric rational interpolation collocation method (BRICM). The model accounts for the effects of thermal radiation and is linearized using Newton's linear iteration method. In the spatial dimension, the two-dimensional heat conduction equation is discretized using BRICM, while in the temporal dimension, it is discretized using the finite difference method (FDM). The resulting temperature distribution of the brake disc during two consecutive braking events is consistent with experimental data. Additionally, factors affecting the accurate calculation of the temperature are examined. Compared to other models, the proposed model achieves accurate temperature distributions with fewer nodes. Furthermore, the numerical results highlight the significance of thermal radiation within the model. The results obtained using BRICM can be used to predict the two-dimensional temperature distribution of train brake discs. [ABSTRACT FROM AUTHOR]

The uniform temperature distribution on the surface of the electromagnetic control roll (ECR) has a great impact on the quality of the strip; therefore, temperature control is essential. In order to study this issue, a two-dimensional volume of fluid (VOF) model was established using the simulation software FLUENT (2024 R1) to analyze the radial cooling capacity and surface temperature uniformity of the ECR under different process parameters, and an experimental validation was carried out at the same time. The error between the experiment and the model was less than 5% of the maximum temperature, proving the model is accurate. The results of the analysis show that the use of a controlled temperature mode has an effect on the cooling capacity and the speed has no effect on the cooling capacity. The temperature difference between the two sides of the ECR is too large, which will make the uniformity of the ECR surface temperature worse. While too high or too low, a roll speed and coolant injection speed will increase the non-uniformity of the ECR surface temperature; when the roll speed is 12 rad/s or coolant injection speed is 5 m/s, the ECR surface temperature distribution uniformity is the best. Properly adjusted process parameters can improve the cooling performance and ECR surface temperature uniformity. [ABSTRACT FROM AUTHOR]

Engineering practice has demonstrated that seal failure can result in severe leakage and wear, reducing the efficiency of hydraulic systems and even leading to major safety risks. Currently, analyses of the thermal aspect of seal interfaces are relatively limited, with most studies focusing on mechanical analysis. However, in actual applications, temperature has a significant impact on sealing performance. In this paper, nonlinear elastomechanics, viscous fluid mechanics, micro-contact mechanics, micro-deformation theory, and thermodynamics are coupled to establish a mixed lubrication model considering the thermal effect. The reliability of the mixed lubrication model is verified through experiments, and the temperature distribution of the oil film in the sealing area and the temperature distribution of the seal ring are simulated. Finally, the effects of the reciprocating speed, root mean square roughness, fluid medium pressure, and seal pre-compression on seal friction force and leakage are investigated. The results show that the heat generated in the sealing area accumulates at the bottom of the V-ring. Under the same conditions, compared with the instroke, the temperature-rise area of the outstroke is biased to the left and the increase in temperature is greater. In addition, the piston rod speed and the preliminary compression of the seal ring have a greater impact on the overall seal friction force and leakage. Under a lower seal pre-compression, the RMS roughness has a great influence on the leakage and friction in the outstroke, while the impact of the internal stroke is limited. [ABSTRACT FROM AUTHOR]

The circulation depth of geothermal water providing the geothermal system framework significantly dominates the evaluation of renewal capacity and geothermal resources. The traditional evaluation of circulation depth is based on the groundwater temperature variation in the recharge section and the average geothermal heating rate of geothermal system. However, misunderstanding groundwater temperature distribution in geothermal systems will lead to overestimating groundwater circulation depth based on the recharge section. Temperature measurement in a 1000 m geothermal scientific borehole from the Xinzhou geothermal field of south China is discussed as a case study to reassess the circulation depth of geothermal water. For Xinzhou geothermal system, the recharge and discharge temperatures are from 26.2 °C to 32.6 °C and from 67.0 °C to 98.0 °C, respectively. And the heat exchange temperature at the deepest point is from 121 ℃ to 154 ℃. This indicates that the temperature gradient in the recharge section should be greater than that in the discharge section. But the actual observation is opposite that the temperature gradient in the recharge section and in the discharge section is 3.04 ℃/100 m and 4.97 ℃/100 m, respectively. We proposed that the depth of geothermal water circulation evaluated by the temperature change and the geothermal heating rate in the discharge section represents the top depth of convection in the heat exchange zone, and the depth evaluated by the recharge section represents the advection depth of groundwater in the recharge section. The top depth of convection in the heat exchange zone estimated by the discharge Sect. (0.75–1.49 km) is much shallower than the advection depth of groundwater in the recharge Sect. (3.25–4.34 km). In the convective heat exchange zone (between 4.34 km and 1.49 km), the fault zone at a certain depth is the ideal location for geothermal development to extract water and heat. [ABSTRACT FROM AUTHOR]

Called island-crossing tunnels, some specific underwater tunneling projects face constraints imposed by geological and water conditions, necessitating their passage through artificial or natural islands. The longitudinal of the tunnel follows a W-shaped distribution. The congestion situation does not allow for immediate longitudinal smoke exhaust at the early stage of the fire, and the natural spread of smoke is complicated. An exhaustive investigation was carried out to analyze the smoke behaviors during a fire incident, employing the fire dynamics software FDS, considering five slopes and four fire locations. The simulation results reveal that the layer of high-temperature smoke becomes thicker as one gets closer to the fire source. The thermal pressure difference significantly impacts the temperature distribution within the tunnel and the distance of smoke spread. The value of the thermal pressure difference is significantly affected by changes in slope. It reaches a maximum of 157 Pa at a 5% slope, while it is only 41 Pa at a 1% slope when the fire occurs at the V-point. Fire hazards vary across locations within the W-shaped tunnel, necessitating separate consideration of the V-point and inverted V-point fire characteristics. The mass flow rate in small and large slope tunnels shows different decay rates due to variations in the main forces acting on the movement. Hence, two equations have been developed to predict the smoke mass flow rate, indicating a nonlinear relationship with the tunnel slope and the distance from the fire source. The tunnel slope inversely affects the smoke mass flow rate at the same location. The results can be utilized as a reference for conducting evacuation operations and aiding rescues during a W-shaped tunnel fire. [ABSTRACT FROM AUTHOR]

The uniformity of performance parameters such as electric field and temperature for a co‐linear pulsed electric field (PEF) processing system is one of main factors affecting the processing effect and quality of liquid food. We have proposed a co‐linear PEF treatment chamber configuration with sub‐electrodes to improve the uniformity and processing efficiency. We have first examined how the position of the sub‐electrodes alone affects the uniformity of the performance parameters. Then, we have investigated the variation of the uniformity while changing simultaneously the electrode radius, inter‐electrode gap, and position of sub‐electrodes. As a result, we have found that the most uniform field could be obtained when the electrode radius is 5.5 mm, the inter‐electrode gap is 15 mm, and the sub‐electrodes situate at the middle of the chamber. In this chamber, the region between 95% and 105% of the average electric field covers 83%, which shows much improvement compared to the formers' results, 69.5% and 76%, respectively. Also, the optimal treatment chamber provides greater average electric field under the same voltages as the voltages reported by the formers. Practical applications: A novel treatment chamber with sub‐electrodes is proposed for pulsed electric fields food processing. The improved treatment design was obtained by changing position of sub‐electrodes, inner radius of electrodes and distance between electrodes. The more uniform electric field was obtained in treatment region. The temperature distribution was more uniformed by increasing flow rates and uniformed electric field strength. The treatment throughput was increased by sub‐electrodes. [ABSTRACT FROM AUTHOR]

Thermal simulation is essential in wire-arc-directed energy deposition (W-DED) to accurately estimate temperature distributions, impacting residual stress and distortion in components. Proper calibration of simulation models minimizes inaccuracies caused by varying material properties, machine settings, and environmental conditions. The lack of standardized calibration methods further complicates thermal predictions. This paper introduces a novel calibration method integrating both machine learning, as the high-fidelity (HF) model, and response surface modeling, as the low-fidelity (LF) model, within a multi-fidelity (MF) framework. The approach utilizes Bayesian optimization to effectively explore the search space for optimal solutions. A two-tiered model employs the LF model to identify feasible regions, followed by the HF model to refine calibration parameters, such as thermal efficiency (η), convection coefficient (h), and emissivity (ε), which are difficult to determine experimentally. A three-factor Box–Behnken design (BBD) is applied to explore the design space, requiring only thirteen parameter configurations, conserving resources and enabling robust model training. The efficacy of this MF model is demonstrated in multi-layer W-DED calibration, showing strong alignment between experimental and simulated temperatures, with a mean absolute error (MAE) of 7.47 °C. This method offers a replicable framework for broader additive manufacturing processes. [ABSTRACT FROM AUTHOR]

Jupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope (JWST)/Mid‐Infrared Instrument (4.9–27.9 μ ${\upmu }$m) in July and August 2022. These observations took place alongside a suite of visual and infrared observations from; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observers which provided both spatial and temporal context across the jovian disc. The stratospheric temperature structure retrieved using the NEMESIS software revealed a series of hot‐spots above the GRS. These could be the consequence of GRS‐induced wave activity. In the troposphere, the temperature structure was used to derive the thermal wind structure of the GRS vortex. These winds were only consistent with the independently determined wind field by JWST/NIRCam at 240 mbar if the altitude of the Hubble‐derived winds were located around 1,200 mbar, considerably deeper than previously assumed. No enhancement in ammonia was found within the GRS but a link between elevated aerosol and phosphine abundances was observed within this region. North‐south asymmetries were observed in the retrieved temperature, ammonia, phosphine and aerosol structure, consistent with the GRS tilting in the north‐south direction. Finally, a small storm was captured north‐west of the GRS that displayed a considerable excess in retrieved phosphine abundance, suggestive of vigorous convection. Despite this, no ammonia ice was detected in this region. The novelty of JWST required us to develop custom‐made software to resolve challenges in calibration of the data. This involved the derivation of the "FLT‐5" wavelength calibration solution that has subsequently been integrated into the standard calibration pipeline. Plain Language Summary: Regularly observed for over 150 years, Jupiter's Great Red Spot (GRS) is one of the best documented storms in the Solar System. Despite the frequency of observations, crucial questions remain unanswered regarding the internal composition, dynamics and driving mechanism for the storm. Mid‐infrared observations acquired by the James Webb Space Telescope allowed us to peer past the colorful clouds to assess the composition and dynamics of the jovian weather layer. Data from the mid‐infrared instrument was modeled in the 7.30–10.75 μ ${\upmu }$m range to "retrieve" the temperature distribution. Further modeling of these temperatures allowed us to derive the wind speeds throughout the vortex, enabling us to assess the dynamics of the GRS and how the vortex interacts with its surroundings. In addition, a series of hot‐spots were observed above the GRS that could be the result of atmospheric wave activity. The distribution of ammonia was also mapped in this spectral range. Comparison of the distribution of ammonia to the cloud distribution implied that this molecule may condense into the thick layers of cloud above the GRS. Finally phosphine, indicative of upwelling air was mapped and allowed us to identify a small convective storm north‐west of the GRS. Key Points: Jupiter's Great Red Spot (GRS) was observed by James Webb Space Telescope/Mid‐Infrared Instrument in 2022 to study the 3D structure of temperature, aerosols and gaseous speciesA series of stratospheric hot‐spots were discovered to be co‐moving with the GRS in the longitude directionElevated phosphine and a complex distribution of ammonia gas were observed inside the GRS [ABSTRACT FROM AUTHOR]

The heating system is an essential component of the glass molding process. It is responsible for heating the glass to an appropriate temperature, allowing it to soften and be easily molded. However, the energy consumption of the heating system becomes particularly significant in large-scale production. This study utilized G-11 glass for the simulation analysis and developed a finite element model for the thermal conduction of a 3D ultra-thin glass molding system, as well as a thermal bending model for smartwatches. Using finite element software, the heat transfer between the mold and the glass was modeled, and the temperature distribution and thermal stress under various processing conditions were predicted. The findings of the simulation, when subjected to a numerical analysis, showed that heating rate techniques significantly affect energy consumption. This study devised a total of four heating strategies. Upon comparison, optimizing with heating strategy 4, which applies an initial heating rate of 35 mJ/(mm2·s) during the initial phase (0 to 60 s) and subsequently escalates to 45 mJ/(mm2·s) during the second phase (60 to 160 s), resulted in a reduction of 4.396% in the system's thermal output and a notable decrease of 7.875% in the heating duration, respectively. Furthermore, a single-factor research method was employed to study the forming process parameters. By comparing the numerical simulation results, it was found that within the temperature range of 615–625 °C, a molding pressure of 25–35 MPa, a heating rate of 1.5–2.5 °C/s, a cooling rate of 0.5–1 °C/s, and a pulse pressure of 45–55 Hz, the influence on residual stress and shape deviation in the glass was minimal. The relative error range was within the 20% acceptable limit, according to the experimental validation, which offered crucial direction and ideas for process development. [ABSTRACT FROM AUTHOR]

Large-size and high-resolution AMOLED displays have become one of the most attractive display technologies. However, the dependence of the luminance of AMOLED on temperature severely limits wider applications. The accurate temperature distribution is important for implementing compensation into a panel to improve display uniformity. With the increase in size and resolution, the voltage drop (IR-drop) caused by the resistance of the power supply line cannot be ignored, which has influence on temperature distribution. Therefore, this paper proposes a temperature distribution analysis method based on IR-drop. Firstly, an accurate solution of IR-drop of AMOLED panels is achieved by exploiting the sparse representation in the field of artificial intelligence. Secondly, the IR-drop-based power model is established, and the output of the power model is used as the input of the AMOLED thermal simulation model. Finally, the temperature distribution of the AMOLED panel is obtained by finite-element analysis. The temperature measurements are performed on a 95-inch 8K AMOLED panel. The simulation results are compared with the actual measurements, and it is found that the temperature distribution based on IR-drop matches well with the actual measurements than that without considering IR-drop. The analysis method proposed in this paper presents high accuracy and high practicability. [ABSTRACT FROM AUTHOR]

To investigate the combustion process and reduce Nitric Oxide (NO) emissions in the vertical heating flue of air-staged coke ovens, a three-dimensional computational fluid dynamics method was applied to simulate the combustion process. The model integrates the k-ε turbulence model with a multi-component transport combustion model. The impact of air staging on the flow field and NO emissions in the vertical fire chamber was assessed through comparative validation with experimental data. The impact of air staging on the flow field and NO emissions in the vertical fire chamber was assessed through comparative validation with experimental data. Based on this research, the effects of the excess air coefficient and air inlet distribution ratio on NO emission levels at the flue gas outlet were further investigated. Analysis of the flow field structure, temperature at the center cross-section, component concentration, and NO emission levels indicates that as the excess air coefficient increases, the NO emission levels at the flue gas outlet initially decrease and then increase, accompanied by corresponding changes in outlet temperature. At an air excess factor of 1.3 and an air inlet distribution ratio of 7:3, NO emission levels are at their lowest—53% lower than those in a conventional coke oven—and the temperature distribution in the riser channel is more uniform. These results provide a theoretical foundation for designing the air-staged coke oven standing fire channel structure. [ABSTRACT FROM AUTHOR]

The heat pipe (HP) is widely applied in the thermal management field at present. In order to make use of the low-grade and renewable energies to maintain building thermal comfort in the heating season, more and more studies with respect to improving the thermal performance of the building heating system integrated with the HP (BHSIHP), such as the floor heating system integrated with the HP (FHSIHP), the thermal storage wall heating system integrated with the HP (TSWIHP), conventional wall integrated with the HP (WIHP) and radiator heating system integrated with the HP (RHSIHP), are conducted. This paper aims to summarize different types of HPs applied in the building heating system and offers an overview of the thermal performance improvement for the BHSIHP. The thermal response, thermal conductivity, thermal resistance, heat capacity, heat transfer coefficient, temperature distribution, thermal storage and heat release capacity are always selected to investigate characteristics of the BHSIHP. Results show that the thermal performance of the FHSIHP, the TSWIHP, the WIHP and the RHSIHP is more outstanding than that of the conventional heating system. The thermal performance of the BHSIHP is affected by heat source temperature, installation tilt angle, working fluid, and filling ratio of the HP. The heat source temperature, which positively affects the performance of the BHSIHP, is crucial for the selection of the working fluid and filling ratio. However, the performance of the BHSIHP is increased first and then decreased with the increase of the installation tilt angle. The optimal filling ratio of the working fluid has been proven not to be a fixed value. [ABSTRACT FROM AUTHOR]

Periodic changes in wellbore temperature and pressure caused by the cyclic injecting and producing of gas storage wells affect wellbore integrity. To explore the distribution and influencing factors of wellbore temperature and pressure during gas storage well injection-production processes, based on energy conservation, momentum theorem, and the transient heat transfer mechanism of the wellbore, a temperature and pressure coupling model for gas storage injection-production wellbores was established, and a piecewise iterative method was used to solve the model equations. Compared with the field data, the predicted relative errors of the wellhead temperature and pressure were 2.30% and 2.07%, respectively, indicating that the coupling model has a high predictive accuracy. The influences of the injection-production conditions, tubing diameter, and overall heat transfer coefficient on the wellbore temperature and pressure distributions were analyzed through an example. When the gas injection flow rate increased by 1.5 times, the bottomhole temperature decreased by 37%. Doubling the overall heat transfer coefficient resulted in a 10% rise in the bottomhole temperature. An increase of 0.3 times in the gas injection pressure led to a 31% increase in bottomhole pressure. With a 1.5-fold increase in the gas production flow rate, the wellhead temperature rose by 28%, and the wellhead pressure dropped by 20%. The research in this paper can serve as a guide for the optimization design and safe operation of gas storage wells. [ABSTRACT FROM AUTHOR]

Three triangular friction block configurations are commonly employed in high-speed train brake systems, namely, unperforated, perforated configuration with one circular hole, and perforated with three circular holes. In this study, we adopted these friction block types to investigate the effect of perforated friction block configurations on the brake performance of high-speed trains based on a self-developed brake test rig. The results indicate the significant impact of the number of the holes on the wear behavior, temperature distribution, and vibration characteristics of the brake interface. The friction surface of the unperforated block is covered by wear debris, while the perforated blocks produce less wear debris. Furthermore, the one-hole block exhibits a more uniform temperature distribution and better vibration behavior than that with three holes. The friction brake is a dynamic process, during which separation and attachment between the pad and disc alternatively occur, and the perforated structure on the friction block can both trap and expel the wear debris. [ABSTRACT FROM AUTHOR]

Clarifying the distribution of temperature and pressure in the wellbore and cavern during hydrogen injection and extraction is crucial for quantitatively assessing cavern stability and wellbore integrity. This paper establishes an integrated flow and heat transfer model for the cavern and wellbore during hydrogen injection and withdrawal, analyzing the variations in temperature and pressure in both the wellbore and the cavern. The temperature and pressure parameters of hydrogen and natural gas within the chamber and wellbore were compared. The specific conclusions are as follows. (1) Under identical injection and withdrawal conditions, the temperature of hydrogen in the chamber was 10 °C higher than that of natural gas, and 16 °C higher in the wellbore. The pressure of hydrogen in the chamber was 2.9 MPa greater than that of natural gas, and 2.6 MPa higher in the wellbore. (2) A comparative analysis was conducted on the impact of surrounding rock's horizontal and numerical distance on temperature during hydrogen and natural gas injection processes. As the distance from the cavity increases, from 5 to 15 m, the temperature fluctuation in the surrounding rock diminishes progressively, with the temperature effect in the hydrogen storage chamber extending to at least 10 m. (3) The influence of rock thermal conductivity parameters on temperature during the processes of hydrogen injection and natural gas extraction is also compared. The better the thermal conductivity, the deeper the thermal effects penetrate the rock layers, with the specific heat capacity having the most significant impact. [ABSTRACT FROM AUTHOR]

In addressing the retrofitting issues of conventional non-induction heating tundish, a novel butterfly-type induction heating tundish model was devised. A three-dimensional coupled mathematical model of magnetic, thermal, and fluid fields was established to investigate the temperature distribution, flow characteristics, and temperature rise curves within the butterfly-type tundish. The model for inclusion motion and removal, based on Large Eddy Simulation (LES), was devised, integrating factors such as normal critical velocity, coefficient of restitution, and critical incident angle at the wall boundary conditions to provide a more precise depiction of the reflection and adsorption processes of inclusions on the tundish wall. The findings suggest that induction heating can effectively offset the temperature loss of the molten steel and enhance the removal rate of inclusions, particularly those of large size. The outlet temperature increases by − 15 K, 7 K, 15 K, and 26 K, and the total removal rate of inclusions reaches 69.18, 83.37, 87.69, and 92.01 pct at 0, 600, 800, and 1000 kW, respectively. The channel serves as the primary site for inclusion removal when employing induction heating. Among these, the removal rates within the channel and at the slag layer exhibit a positive correlation with the inclusion diameter, while the remaining wall removal rates show a negative correlation. The implementation of induction heating technology leads to a notable decrease in the entry of large-sized inclusions into the mold. [ABSTRACT FROM AUTHOR]

Purpose: Investigating the performance of the new Dophi™ M150E Microwave Ablation System, in terms of temperature distribution, ablation size and shape, reproducibility. Materials and Methods: The Dophi™ M150E Microwave Ablation System was tested on ex vivo liver, lung and kidney, at 6 different settings of time, power and number of MW antennas (single antenna: 50 and 100 W at 5 and 10 min; double antenna: 75 W at 5 and 10 min). The temperature distribution was recorded by Fiber Bragg Grating sensors, placed at different distances from the antennas. The ablation axes were measured and the sphericity index was calculated. Results: The standard deviation of ablation axes was < 5 mm, except at the highest energy and time setting for the lung. A maximum temperature rise of ~ 80 °C was measured. The measured ablation axes are overall comparable with the manufacture's values, especially at lower power and with one MW antenna (average maximum difference is 7 mm). The mean sphericity index of 0.95, 0.79 and 0.9 was obtained for the liver, lung and kidney, respectively, with a single antenna. With double antenna setup, the sphericity index was closer to 1 when 75 W for 10 min were used. Conclusions: Dophi™ M150E allows good reproducibility of ablation axes for all cases except in the lung at the highest energy level. With one antenna, an almost spherical ablation area for the liver and kidney was obtained. Using double antenna results in more homogeneous temperature distribution within the tissue compared to single antenna. [ABSTRACT FROM AUTHOR]

Optimizing the flow channel structures can improve the efficiency of proton exchange membrane fuel cells and promote the efficient utilization of clean energy. This study investigates the impacts of rectangular-baffle and tapered flow channels on electrical performance, temperature distribution and mass transfer of proton exchange membrane fuel cells, based on a 3D, multi-physical model. The equivalent average depth is adopted as the reference benchmark to mitigate the influence of channel depth. Results indicate that adopting variable-depth channels enhances convective mass transfer on the porous layer surface under higher voltage. The convective mass transfer of oxygen is dominant in the activation polarization region, while diffusion is dominant in the concentration polarization region. Variable-depth channels enhance heat and mass transfer in comparison to the straight channel. The tapered channel can improve the mass transfer flux in oxygen starvation region, and the drainage ability of the rectangular baffle channel is inferior to the tapered channel. The rectangular baffle channel demonstrates better convective heat transfer performance and temperature uniformity. A rectangular-baffle channel can increase net power by 4.31%, while a tapered channel can achieve a maximum increase of 9.27% when the pumping power is considered. Therefore, incorporating a tapered channel is an optimal strategy to boost cell efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A depth investigation into the impact of high temperatures on the load‐bearing capacity of reinforced concrete beams in the case of probabilistic design is presented in this paper, employing advanced finite element analysis techniques. This study addresses a critical knowledge gap in the design of fire‐resistant concrete structures, with specific emphasis on the function of concrete cover. The research aims to enhance the overall safety and reliability of concrete buildings under high temperature conditions by providing valuable insights into the behavior of reinforced concrete beams under thermal loading. The analysis incorporates reliability‐based modeling to account for uncertainties in temperature distribution within the beams. A validated finite element model is employed to simulate the performance of reinforced concrete beams at elevated temperatures. By considering various concrete cover thicknesses and heat distribution scenarios, the influence of these factors on the load‐bearing capacity is thoroughly examined. The results underscore the importance of augmenting the concrete cover to enhance the load‐carrying capacity of the beams. Furthermore, the study examines the impact of temperature distribution uncertainties, unveiling diverse load capacities associated with different configurations of concrete cover. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work presents a characterisation model for the temperature distribution at different substrate depths during the atmospheric plasma spray (APS) coating process. The torch heat flow in this model is simulated as forced convection defined by a surface, a temperature profile, and a convection coefficient. The simulation model considers three plasma temperature profiles of the Al2O3 coating on a 5 mm thickness flat aluminium substrate. The simple and low-cost experimental procedure, based on a thermocouple, measures the plasma plume temperature distribution of the APS coating system, and their results are used to obtain the parameter values of each of the three proposed plasma temperature profiles. The experimental method for in situ non-contact temperature measurements inside the substrate is based on an infrared pyrometry technique and validates the simulation results. The Gaussian temperature profile shows excellent accuracy with the measured temperatures. The Gaussian approach could be a powerful tool for predicting residual stress through a coupled one-way thermal-mechanical analysis of the APS process. [ABSTRACT FROM AUTHOR]

The effect of fire source location (FSL) on compartment fire phenomena with a single natural ceiling vent was experimentally investigated under various vent area (VA) and heat release rate (HRR) conditions. Two FSL cases, where the fire source was located at the centre (FSLC) and on the side (FSLS) of the floor, were tested. In the bidirectional vent flow patterns of FSLC and FSLS, the detailed locations where the smoke outflow and the fresh air inflow occurred were different. Empirical correlations were proposed for predicting the smoke outflow areas. FSLC exhibited a higher central velocity of the outflow, larger estimated mass flow rate of the outflow, and lower temperatures inside the compartment than FSLS. The estimated mass flow rate of the outflow depended more on VA than on HRR. A previous correlation was more suitable for FSLS than FSLC in predicting the mass flow rate of the outflow. [ABSTRACT FROM AUTHOR]