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In order to investigate the risk of low temperature freezing damage in winter for thermophilic vegetables in greenhouse in Fujian province, this study utilized the meteorological monitoring data from representative plastic greenhouses in Fuqing and Qingliu from December 2020 to February 2023, as well as assimilated land surface minimum temperature data during the same period. Regression models were developed for the minimum temperature inside the greenhouse under different weather conditions, such as sunny, cloudy, overcast and rainy. Based on data from the 66 meteorological stations in Fujian province from 1991 to 2020, daily minimum temperature inside greenhouse were inferred from December to February in previous years. Based on the low-temperature data inside the greenhouses, authors constructed a risk classification index system for freezing damage of thermophilic vegetables in greenhouses in Fujian. The weights of the indicators were determined by using the subjective-objective comprehensive weight method, and a risk assessment model for freezing damage was established to carry out the risk zoning of freezing damage in greenhouse for thermophilic vegetables in Fujian province. The results showed that: (1) the regression models for the minimum temperature in the greenhouse during winter under different weather conditions, including sunny, cloudy, overcast, and rainy, had R² greater than 0.75, and the absolute errors of the model validation were 0.6°C, 1.4°C, 1.0°C, and 0.5°C, respectively. (2) The low-risk area for cold and freezing damage of thermophilic vegetables in greenhouse mainly distributed in the coastal counties and cities south of Fuzhou with elevations below 200m. The medium-risk area mainly concentrated in the coastal areas of the north and the inland areas of the south with elevations between 200m and 500m. The moderate-risk area was mainly distributed in the middle and high altitude mountainous areas with elevations between 500m and 1000m in the southern inland and the coastal areas with elevations between 200m and 500m in the north, basically surrounding the areas with severe freezing damage and extending to lower elevations. The high-risk area mainly distributed in the areas above 1000m in Wuyi mountains, Jiufeng mountains, Daiyun mountains, Boping ridge, and Daimao mountain, where significant losses occurred and were not suitable for greenhouse thermophilic vegetable cultivation. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office 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.)

The thick large circular storage tank of heavy launch vehicle is made of 2219 aluminum alloy and welded using friction stir welding (FSW) technology. To explore the temperature distribution of friction stir girth welding in circular storage tank and select welding parameters, a simulation model of temperature field is established based on ABAQUS/CEL method, combining the amplitude-periodic function to define the mechanical boundary condition and implement motion synthesis based on the parallelogram rule to realize the trace setting of the tool during welding stage of girth welding. The simulation model is verified through temperature measurement with infrared thermal imager. By comparing with the temperature field of FSW plate, the temperature distribution rule of girth welding circular tank is explored. Optimizing with the goals of reducing the length of heat-affected zone and the temperature difference in the thickness direction of the weldment, the process parameters are obtained based on the response surface method–multi-objective particle swarm optimization algorithm. The Pareto optimal solution set is obtained which provides guidance for the selection of welding process parameters. [ABSTRACT FROM AUTHOR]

With the continuous improvement of the operating temperature of aero transmission under the high-speed and high load, gear scuffing failure has become a key factor restricting the performance of aircrafts. To efficiently predict the operating temperature of aero gears, a sequential coupling numerical analysis method of the gear temperature is proposed for an aero engine gear, which simulates the bulk temperature and flash temperature under different working conditions, considering factors such as solid-liquid-gas multi-state flow heat exchange and heat dissipation coefficients of different tooth surfaces. The simulated gear contact temperature is compared with calculation results of ISO/TS 6336-20 and shows consistency, the largest deviation between which under different working conditions is controlled within 10%. When the input speed is 22 400 r/min and the torque is 119.4 N∙m, the split large gear contact temperature reaches 242.6 ℃, the scuffing safety factor is 1.22, and there is a risk of scuffing failure. The proposed simulation analysis method can effectively predict the operating temperature of aero high-speed gears, and provide an efficient and reliable method for assessing the risk of aero gear scuffing failure.

The environmental control of layer houses with multi-tiered cage systems is influenced by factors such as the structure of the henhouses and the heat dissipation of the flock, leading to low precision and large fluctuations in temperature control. Based on a new combined positive- and negative-pressure ventilation (CPNPV) mode, a dynamic temperature model is constructed. Additionally, a temperature control method for a layer house is designed using a variable universe fuzzy PID control algorithm (VFPID). First, based on the principles of energy and mass balance, and by decoupling the relationship between positive- and negative-pressure ventilation volumes, a dynamic temperature model for layer houses under CPNPV was established. Then, the PID parameters and the proportional relationship between positive- and negative-pressure ventilation were optimized through fuzzy rules, and a proportional exponential function was introduced to adjust the scaling of the universe, enabling fine-tuned control. Finally, a temperature control model for the layer house was built using Simulink. The results show that the coefficients of determination (R2) of the constructed dynamic temperature models are between 0.79 and 0.88, respectively, indicating high accuracy. The designed VFPID method outperformed traditional on–off control and improved control precision by 20–23.53% and 10.34–22.22% compared with PID control and fuzzy PID(FPID) control methods, respectively. This study provides new insights for the development of environmental control equipment and precise environmental regulation of layer houses.

A physically-based image processing approach, based on a single-source surface energy balance framework, is developed here to model the land surface temperature (LST) over complex/rugged geologic terrains at medium to high spatial resolution (<102 m). This approach combines atmospheric parameters with a bulk-layer soil model and remote-sensing-based parameterization schemes to simulate surface temperature over bare surfaces. The model's inputs comprise a digital elevation model, surface temperature data, and a set of land surface parameters including albedo, emissivity, roughness length, thermal conductivity, soil porosity, and soil moisture content, which are adjusted for elevation, solar time, and moisture contents when necessary. High-quality weather data were acquired from a nearby weather station. By solving the energy balance, heat, and water flow equations per pixel and subsequently integrating the surface and subsurface energy fluxes over time, a model-simulated temperature map/dataset is generated. The resulting map can then be contrasted with concurrent remote sensing LST (typically nighttime) data aiming to remove the diurnal effects and constrain the contribution of the subsurface heating component. The model's performance and sensitivity were assessed across two distinct test sites in China and Iran, using point-scale observational data and regional-scale ASTER imagery, respectively. The model, known as the Surface Kinetic Temperature Simulator (SkinTES), has direct applications in resource exploration and geological studies in arid to semi-arid regions of the world. [ABSTRACT FROM AUTHOR]

This paper presents a strategy for direct‐driving a turbine with an external rotor high‐speed permanent magnet motor. It is used to improve the large footprint, low efficiency, high maintenance costs, and high vibration risk of turbines. Combining the characteristics of the working conditions of pipeline gas transmission, this paper takes a 200 kW, 10 000 rpm external rotor high‐speed permanent magnet motor as an example. This paper analyzes the eddy current losses in the rotor due to the armature magnetomotive force generated by the stator fundamental and harmonic currents. To reduce eddy current losses in permanent magnets, a circumferentially segmented pole structure is proposed for theoretical comparison and FEA with common surface‐mounted pole structures under different loads and work angles. The results confirm that the circumferentially segmented pole can effectively reduce the eddy current loss of the permanent magnet rotor. The effect of variations in the pole arc coefficient on eddy current losses in permanent magnets is also analyzed. Finally, the temperature field simulation of the motor is carried out under consideration of wind mill losses. By setting up three comparison groups with different conditions, this paper analyses the influence of the temperature and flow rate of the gas on the temperature rise and heat dissipation of the motor in a high‐temperature gas environment. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Featured with the harmonic sinusoidal function to reflect temperature effects, the hydrostatic-season-time (HST) model is often used to monitor the concrete gravity dam health, but it does not take account of the effects of environment temperatures in real-term and has flaws especially when applied in conditions of significant temperature variations. A model of Sparrow Search Algorithm optimized error Back Propagation neural network (SSA-BP) based on the hydrostatic-temperature-time (HTT) model is proposed in this paper for predicting the concrete gravity dam displacement using the long-term environment temperature variable sets to reflect temperature effects. Successive Projections Algorithm (SPA) is used for the first time for feature selection on long-term temperature variables to further optimize the model (as SPA-SSA-BP). Through a case study with the practical observed data from a reality high concrete gravity dam, the effectiveness of the new model is verified, suggesting that HTT-based SSA-BP models have better performance than HST with the best result obtained when using the 2-year long variable sets. The SSA-BP model has much lower error in predicting the concrete dam displacement than Multiple Linear Regression (MLR). The arithmetic speed and prediction accuracy of the SPA-SSA-BP model is optimized as it can minimize the collinearity among feature variables in the long-term HTT variable sets, bring down the input variable dimension close to the level of HST, and diminish the redundant data information. [ABSTRACT FROM AUTHOR]

The rapid development of natural gas pipelines has highlighted the need to utilize SCADA (supervisory control and data acquisition) system data. In this paper, a heat transfer model of a natural gas pipeline based on data feature extraction and first principle models, which makes full use of the measured temperatures at each end of the pipeline, is proposed. Three methods, the NARX neural network (nonlinear autoregressive neural network with exogenous inputs), time series decomposition, and system identification, were used to model the changes of gas temperatures of the pipeline. The NARX neural network method uses a cyclic neural network to directly model the relationship of temperature between the start and the end of the pipeline. The measured temperature series at the pipeline inlet and outlet were decomposed into trend items, fluctuation items, and noise items based on the time series decomposition method. Then the three items were fitted separately and combined to form a new temperature prediction series. The system identification method constructed the first-order and second-order transfer function to model the temperature. The simulation of the three data-driven models was compared with those of the physics-based simulation models. The results showed that the data-driven model has great advantages over the physics-based simulation models in both accuracy and efficiency. The proposed models are more suitable for applications such as online simulation and state observation of long-distance natural gas pipelines. [ABSTRACT FROM AUTHOR]

A physically-based image processing approach, based on a single-source surface energy balance framework, is developed here to model the land surface temperature (LST) over complex/rugged geologic terrains at medium to high spatial resolution (2 m). This approach combines atmospheric parameters with a bulk-layer soil model and remote-sensing-based parameterization schemes to simulate surface temperature over bare surfaces. The model’s inputs comprise a digital elevation model, surface temperature data, and a set of land surface parameters including albedo, emissivity, roughness length, thermal conductivity, soil porosity, and soil moisture content, which are adjusted for elevation, solar time, and moisture contents when necessary. High-quality weather data were acquired from a nearby weather station. By solving the energy balance, heat, and water flow equations per pixel and subsequently integrating the surface and subsurface energy fluxes over time, a model-simulated temperature map/dataset is generated. The resulting map can then be contrasted with concurrent remote sensing LST (typically nighttime) data aiming to remove the diurnal effects and constrain the contribution of the subsurface heating component. The model’s performance and sensitivity were assessed across two distinct test sites in China and Iran, using point-scale observational data and regional-scale ASTER imagery, respectively. The model, known as the Surface Kinetic Temperature Simulator (SkinTES), has direct applications in resource exploration and geological studies in arid to semi-arid regions of the world.

The environmental control of layer houses with multi-tiered cage systems is influenced by factors such as the structure of the henhouses and the heat dissipation of the flock, leading to low precision and large fluctuations in temperature control. Based on a new combined positive- and negative-pressure ventilation (CPNPV) mode, a dynamic temperature model is constructed. Additionally, a temperature control method for a layer house is designed using a variable universe fuzzy PID control algorithm (VFPID). First, based on the principles of energy and mass balance, and by decoupling the relationship between positive- and negative-pressure ventilation volumes, a dynamic temperature model for layer houses under CPNPV was established. Then, the PID parameters and the proportional relationship between positive- and negative-pressure ventilation were optimized through fuzzy rules, and a proportional exponential function was introduced to adjust the scaling of the universe, enabling fine-tuned control. Finally, a temperature control model for the layer house was built using Simulink. The results show that the coefficients of determination (R 2 ) of the constructed dynamic temperature models are between 0.79 and 0.88, respectively, indicating high accuracy. The designed VFPID method outperformed traditional on-off control and improved control precision by 20-23.53% and 10.34-22.22% compared with PID control and fuzzy PID(FPID) control methods, respectively. This study provides new insights for the development of environmental control equipment and precise environmental regulation of layer houses.

The rapid development of natural gas pipelines has highlighted the need to utilize SCADA (supervisory control and data acquisition) system data. In this paper, a heat transfer model of a natural gas pipeline based on data feature extraction and first principle models, which makes full use of the measured temperatures at each end of the pipeline, is proposed. Three methods, the NARX neural network (nonlinear autoregressive neural network with exogenous inputs), time series decomposition, and system identification, were used to model the changes of gas temperatures of the pipeline. The NARX neural network method uses a cyclic neural network to directly model the relationship of temperature between the start and the end of the pipeline. The measured temperature series at the pipeline inlet and outlet were decomposed into trend items, fluctuation items, and noise items based on the time series decomposition method. Then the three items were fitted separately and combined to form a new temperature prediction series. The system identification method constructed the first-order and second-order transfer function to model the temperature. The simulation of the three data-driven models was compared with those of the physics-based simulation models. The results showed that the data-driven model has great advantages over the physics-based simulation models in both accuracy and efficiency. The proposed models are more suitable for applications such as online simulation and state observation of long-distance natural gas pipelines.

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China 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.)

The temperature field caused by solar radiation can seriously affect the electromagnetic (EM) performances of large-aperture and high-frequency radio telescopes, and achieving the EM performance improvements under solar radiation is of great importance. In this study, combining temperature simulation and measurement, a fast estimation method of the temperature field is presented. First, a temperature database based on transient temperature field simulation is constructed in advance, and by utilising the telescope's axisymmetric structure, the dimension of the database can be greatly reduced. Then, a small number of temperature sensors are installed and the real-time measured data are applied to correct the simulation temperature field extracted from the above temperature database by the table look-up method, which can ensure the temperature field estimation speed. Thus, based on the real-time estimated temperature field and the telescope's finite element model, thermal deformations can be calculated in real-time and used for deformation compensation. A 7.3 m reflector antenna with 21 temperature sensors is adopted to verify the proposed strategy, and the results show the effectiveness and feasibility of the strategy. This study can provide helpful guidance for the real-time compensation of thermal deformations derived from large axisymmetric telescopes. [ABSTRACT FROM AUTHOR]

Thermal actions are considered in the design of bridges, as temperature variations can lead to restraint stresses and subsequent cracking. However, load descriptions are in some cases oversimplified or incompatible with modern applications, and background studies are limited. This paper therefore aims to develop a more detailed load description for the load case describing temperature differences between structural parts in bridges, focusing on portal frame bridges. The temperature in portal frame bridges is investigated by performing long-term thermal simulations using weather data from several locations in Sweden, and thereafter performing statistical analyses of the resulting temperature variations over time. The study gives suggestions of both characteristic and quasi-permanent values to be used in design based on the statistical analyses, and also notes a gradual change in temperature between structural parts, which could be considered in the design. The resulting quasi-permanent values are significantly lower than the values given in the Eurocode for temperature differences between structural parts, which, in turn, will lead to smaller and more realistic stress values in bridge design. [ABSTRACT FROM AUTHOR]

For flood control, outlet structure is generally installed in the body of the dam. After pouring, the import and export of the orifice will be covered with thermal insulation materials for insulation. When the dam body is used for water storage and diversion, it is necessary to remove the heat preservation quilt. At this time, the lower temperature water will cause a effect called 'cold shock' on the surface concrete of the bottom orifices, in addition, under the influence of a combination of external factors such as air and water temperatures, a large temperature gradient will appear on the surface of the concrete, which will easily lead to temperature cracks. In this paper, external environment temperature, water temperature, real-time concrete surface heat exchange coefficient and the effect of solar radiation fever in the high temperature season are considered in the temperature field simulation calculation of single bottom orifice during outflowing. The calculation result indicates the simulation model is highly accurate, and the inaccuracy between the calculated and the measured temperature is within 1 °C, which provides theoretical reference for deep orifices and surface orifices in water discharge, temperature control and crack prevention. [ABSTRACT FROM AUTHOR]

Despite temperature rise being a first-order design constraint, traditional thermal estimation techniques have severe limitations in modeling critical aspects affecting the temperature in modern-day chips. Existing thermal modeling techniques often ignore the effects of parameter variation, which can lead to significant errors. Such methods also ignore the dependence of conductivity on temperature and its variation. Leakage power is also incorporated inadequately by state-of-the-art techniques. Thermal modeling is a process that has to be repeated at least thousands of times in the design cycle, and hence speed is of utmost importance. To overcome these limitations, we propose VarSim , an ultrafast thermal simulator based on Green's functions. Green's functions have been shown to be faster than the traditional finite difference and finite element-based approaches but have rarely been employed in thermal modeling. Hence we propose a new Green's function-based method to capture the effects of leakage power as well as process variation analytically. We provide a closed-form solution for the Green's function considering the effects of variation on the process, temperature, and thermal conductivity. Additionally, we propose a novel way of dealing with the anisotropicity introduced by process variation by splitting the Green's functions into shift-variant and shift-invariant components. Since our solutions are analytical expressions, we were able to obtain speedups that were several orders of magnitude more than state-of-the-art proposals with a mean absolute error limited to 4% for a wide range of test cases. Furthermore, our method accurately captures the steady-state as well as the transient variation in temperature. [ABSTRACT FROM AUTHOR]

The reactions that can occur on organic materials treated in plasma enviorement are strongly affected by surface temperature, thus the sharp determination of this variable is extremely important to process control. In situ temperature measurements are often employed; however, the measured point is generally under the treated surface. If in metallic materials the high thermal conductivity minimizes this problem, in non-metallic materials processing it becomes important, because its thermal resistivity besides a high sensibility to small temperature variations. The present work uses a simulation tool to extract thermal data on Ar+O2 RF plasma processing of Stearic Acid. Experimental data were obtained by thermocouples placed inside the samples. The extrapolation of surface temperature was performed by numerical simulation with Autodesk CFD software v.15.1. Results show that the temperature of the surface reaches values higher than the ones measured inside the sample holder. This difference of temperature is in good agreement with the visual observation of the phase transformations in the treated material, showing a simple and valuable tool to better control of plasma treatments.

[Display omitted] • Investigation of the effects of LBPF parameters on crystallographic texture. • Solidification behavior estimated using temperature-field simulations. • Laser power decreases and scanning speed increases the solidification rate. • Numerical simulations can be used to predict the texture of materials. • Simulations can be used to guide the design of textures for specific applications. Recently, the use of laser powder bed fusion (LPBF) to create crystallographic textures, such as single-crystal-like and polycrystalline textures, has attracted attention. However, the relationship between the LPBF conditions and the resulting texture is unclear. This study investigates the effects of the LPBF conditions (laser power and scanning speed) on the texture by estimating the solidification behavior using temperature-field simulations. Herein, we show for the first time that laser power and scanning speed negatively and positively affect the solidification rate R , respectively, and do not affect the thermal gradient G significantly. Thus, when the laser power decreases and scanning speed increases, the G / R ratio decreases and polycrystal formation is enhanced. This is consistent with practical observations. [ABSTRACT FROM AUTHOR]

Florida ranks first among US states in fresh-market tomato production with annual production exceeding one-third of the total annual production in the country. Although tomato is a signature crop in Florida, current and future ambient temperatures could impose a major production challenge, especially during the fall growing season. This problem is increasingly becoming an important concern among tomato growers in south Florida, but studies addressing these concerns have not been conducted until now. Therefore, this study was conducted to determine the impacts of the present ambient temperature conditions and planting dates on tomato productivity in south Florida. The study was conducted using crop simulation model CROPGRO-Tomato of DSSAT (Decision Support System for Agricultural Transfer) version 4.7. Five treatments were evaluated, and included AT (simulated treatment using 14 years of actual daily weather conditions at the study location) while other treatments were conducted based on a percentage (−20%, −10%, +10%, +20%) of AT to simulate cooler and warmer temperature regimes. The results suggested that under the current temperature conditions during the fall growing season in south Florida, average tomato yield was up to 29% lower compared to the cooler temperature regimes. Tomato yield further decreased by 52% to 85% at air temperatures above the current condition. Yield reduction under high temperature was primarily due to lower fruit production. Contrary to yield, both tomato biomass accumulation and leaf area index increased with increase in temperature. Results also indicated that due to changes in air temperature pattern, tomato yield increased as planting date increased from July to December. Therefore, planting date modification during the fall season from the current July–September to dates between November and December will reduce the impacts of heat stress and increase tomato productivity in south Florida.

Highlights • Thermal cycle during flash lamp annealing estimated by calibration and simulation. • Surface melting of known materials suitable for temperature calibration. • Chamber wall reflections considered by a correction factor. • 1D heat equation mostly sufficient to simulate impact of flash lamp annealing. Abstract Flash lamp annealing (FLA) is a modern annealing technique which, starting from microelectronics, has spread over new application areas like flexible electronics, photovoltaics or thin film deposition. Because of the short annealing time in the range of milliseconds and below, FLA allows the suppression of unwanted processes like diffusion, the annealing of temperature-sensible substrates, and the saving of process time and energy. In addition, it is predestined for roll-to-roll applications. However, the determination of the thermal cycle during FLA is challenging. The existing methods for a direct temperature measurement, mostly based on pyrometry, are elaborate and have to solve the problem to detect thermal radiation against the background of the intense flash light. An alternative way is simulation, but now an extended knowledge about the flash and the material system to be flashed is needed. In this work we describe a methodology to determine the thermal cycle during FLA without the need for a direct temperature measurement. This methodology is based on an optical-thermodynamic simulation and calibration experiments which can be implemented with reasonable effort under certain assumptions. The simulation considers not only the properties of the flash and the sample, but also the reflectivity of the chamber walls. Finally, the pros and cons of this methodology are shortly discussed. [ABSTRACT FROM AUTHOR]

Biogeophysical effects of land use and land cover (LULC) changes play a significant role in modulating climate on various spatial scales. In this study, a set of recent LULC products with a spatial resolution of 500 m was developed in China for update in RegCM4 (regional climate model version 4). Two sets of comparative numerical experiments were conducted to study the effects of LULC changes on near-surface temperature simulation. The results show that after LULC changes, areas of crops and mixed woodlands as well as urban areas increase over entire China, accompanied with greatly expanded mixed farming and forests/field mosaics in southern China, and reduced areas of 1) irrigated crops and short grasses in northern China and the Tibetan Plateau, and 2) semi-desert and desert in northwestern China. Improvements in the LULC data clearly result in more accurate simulations of the near-surface temperature. Specifically, increasing latent heat and longwave albedo due to enhanced LULC in certain areas lead to reduction in land surface temperature (LST), while changes in shortwave albedo and sensible heat also exert a great influence on the LST. Overall, these parameter adjustments reduce the biases in near-surface temperature simulation. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation into the failure of steam boiler tubes in a liquefied gas treatment plant. The failure appeared in the form of a window rupture in the boiler tubes of 1.25Cr-0.5 Mo grade steel. Study revealed that a thick magnetite iron oxide layer was formed in the inner surface of these tubes, disturbing the heat flow and rising the temperature of the tubes. Consequently, the internal oxide layer led to a series of metallurgical degradation and the loss in mechanical strength of the boiler tubes. Failure analysis of the steam tubes was carried out by optical and scanning electron microscopy examinations, chemical analysis of the tube material and the results showed that the scales were formed in the inner surface of the tubes. Furthermore, the rise in operational temperature and its distribution were simulated using fluent software and the results were compared against the designed temperature of the tubes. The simulation revealed that the operating temperature of the tubes reached beyond the design temperature, confirming the microstructural degradations i.e., oxidation, decarburization and reduction in the effective tube wall thickness. The extensive scale formation on the steam side and the resultant tube wall thinning was identified as the main cause of failure in the superheater tubes. [ABSTRACT FROM AUTHOR]

ZnO thin film sputtered on alumina substrate is processed by Direct Laser Interference Patterning (DLIP). The heat transfer equation has been simulated for interference patterns with a period of 730 nm and two different fluences (85 mJ/cm 2 and 165 mJ/cm 2 ). A thermal threshold of 900 K, where crystal modification occurs has been calculated, indicating a lateral and depth processing around 173 nm and 140 nm, respectively. The experimentally reproduced samples have been analyzed from the structural and composition point of view and compared to conventional thermal treatments at three different temperatures (600 °C, 700 °C and 800 °C). Promising properties have been observed for the laser treated samples, such as low influence on the thin film/substrate interface, an improvement of the crystallographic structure, as well as a decrease of the oxygen content from O/Zn = 2.10 to 1.38 for the highest fluence, getting closer to the stoichiometry. The DLIP characteristics could be suitable for the replacement of annealing process in the case of substrates that cannot achieve high temperatures as most of flexible substrates. [ABSTRACT FROM AUTHOR]

Compared with traditional hot air drying method, the existence of optimal material layer thickness is a significant phenomenon in microwave thin layer drying process. In the current work, a new initial temperature-based methodology is proposed to predict the optimal thickness and to evaluate the effect of influential factors on optimal thickness. The evaluated optimal material layer thickness by the proposed methodology is consistent with experimentally measured value, and hence confirms that the optimal layer thickness can be predicted exactly through the average temperature of bulk material at the initial 1st min during pre-heating stage. With the help of the proposed methodology, it is discovered that attenuation factor, β, surface convective heat transfer coefficient, h, and environmental air temperature, T e are the main factors that affect the optimal thickness. And a larger β or T e tends to result in a smaller optimal thickness, while the situation for h is just the opposite. These results can play a crucial role in designing apt continuous microwave tunnel drying system or aid in guiding their operations. [ABSTRACT FROM AUTHOR]

In this work, role of temperature simulation is investigated for predicting surface modification of InAs nanowire (NW) using laser irradiation. The surface modification is monitored by Raman spectroscopy. We first establish correlation between simulated temperatures at the surface of an InAs nanowire (NW) with time evolution of Raman spectra on laser irradiation. Transient thermal simulations are performed with ANSYS software using finite element method, considering 3D geometry of the irradiation setup. In the systematic study of laser irradiation (laser power densities ∼ 30–636 kW/cm 2 ) over time duration of ∼8 min, the simulated temperature is found to corroborate well with the corresponding oxidation processes e.g. weak (WP), intermediate (IP) and strong (SP), occurring on the surface of InAs nanowire under various laser irradiation conditions. The predictability of the methodology was then investigated by applying it to random conditions of NW like diameter, aspect ratio and laser power density etc. for i) NWs found in the same sample and ii) InAs NWs grown elsewhere and transferred on other Si substrate. The study establishes predictability of various oxidation processes for given NW dimensions, laser power density and irradiation time, thereby ascertaining importance and applicability of the temperature simulation in controlling surface modification of randomly chosen InAs NWs, as per the requirement for device applications. [ABSTRACT FROM AUTHOR]

A new version of the Community Land Model (CLM) was introduced to the Saudi King Abdulaziz University Atmospheric Global Climate Model (Saudi-KAU AGCM) for better land surface component representation, and so to enhance climate simulation. CLM replaced the original land surface model (LSM) in Saudi-KAU AGCM, with the aim of simulating more accurate land surface fluxes globally, but especially over the Arabian Peninsula. To evaluate the performance of Saudi-KAU AGCM, simulations were completed with CLM and LSM for the period 1981–2010. In comparison with LSM, CLM generates surface air temperature values that are closer to National Centre for Environmental Prediction (NCEP) observations. The global annual averages of land surface air temperature are 9.51, 9.52, and 9.57 °C for NCEP, CLM, and LSM respectively, although the same atmospheric radiative and surface forcing from Saudi-KAU AGCM are provided to both LSM and CLM at every time step. The better temperature simulations when using CLM can be attributed to the more comprehensive plant functional type and hierarchical tile approach to the land cover type in CLM, along with better parameterization of upward land surface fluxes compared to LSM. At global scale, CLM exhibits smaller annual and seasonal mean biases of temperature with respect to NCEP data. Moreover, at regional scale, CLM demonstrates reasonable seasonal and annual mean temperature over the Arabian Peninsula as compared to the Climatic Research Unit (CRU) data. Finally, CLM generated better matches to single point-wise observations of surface air temperature and surface fluxes for some case studies. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) in a gas medium (dry EDM) is an environmentally friendly machining method. However, dry EDM mechanism is not well understood, which limits its development. Understanding the material removal mechanism using a simulation modality is constructive to the EDM mechanism analysis, and it could provide a theoretical support for further improvements in dry EDM performance. In EDM, the heat generated by the dielectric breakdown due to the high electrical field erodes workpiece material; therefore, the crater size is determined by the temperature of the single-pulse discharged. Despite the temperature field of a single-pulse not being completely equal to that of a continuous pulse discharge, the simulation of the temperature field and the study of the characteristics of the crater variation in a single-pulse discharge might provide favorable findings to understand the erosion mechanism of materials in dry EDM. Therefore, a simulation of the temperature field of a single-pulse was performed according to the established thermal transfer model using a finite element software. The center point temperature of the crater varying with discharge time, the evolution features of the crater diameter and crater depth under different pulse durations and peak currents, and the variation of the ratios of crater size by gasification to that by melting were analyzed. The simulation results indicate that when the discharge time was close to 50% of the pulse duration, the temperature of the discharge channel center began to decrease. The ratio of crater diameter by gasification to that by melting decreases with an increase in the pulse width and the discharge current. The experimental results validated the simulation analysis of the discharge crater size. [ABSTRACT FROM AUTHOR]

The present work studied the numerical modelling of heat transfer in a pile of Pinus radiata samples of a square cross-section by using radio frequency heating. More precisely, the study focused on the effects of the energy transferred to a dielectric material (wood) from an electromagnetic field, which required the calculation of the dielectric loss factor and its correlation with conservative equations. In this way, the temperature distribution across Pinus radiata samples was obtained through the integration of the energy equation using the finite volume method. The numerical results were compared to experimental data obtained from three experiments of radio-frequency heating of wood samples of a crosssectional area of 4 in × 4 in, 3.1-m-long, and 20 cm of separation between plates. According to the observed linear behavior of the heat transfer process, the numerical results of the transient variation of temperature were in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

• An analytical solution of heat transfer in karst conduit was proposed. • Conduit structure and flow properties determine thermal equilibrium depth. • Insufficiently heat exchange results in temperature fluctuations in karst springs. • Event thermal response was verified by heat exchange and mixing function. Thermal responses of groundwater are useful signatures to reveal the recharge-discharge process and characterize aquifer structure in karst groundwater. Four karst springs with varying circulation depths ranging from ∼ 60 to 820 m in South China, were used to decipher the mechanism of heat exchange between recharge water and surrounding rock formations. An analytical solution of heat transfer in karst conduit was proposed to simulate the peak or trough temperatures of pulse flow. Hydraulic diameter, flow velocity, input temperature and circulation depth in karst aquifer, mainly depending on the recharge water volume after rainfall events, are important transport factors to control the thermal equilibrium depth and the efficiency of heat exchange that directly controls the behavior of warm peaks or cold troughs in groundwater temperature. In shallow karst aquifers wherein the circulation depth is less than its theoretical thermal equilibrium depth, the recharge water does not sufficiently exchange heat with the surrounding rocks, resulting in clear event-scale warm peaks in summer and cold troughs in winter. Otherwise, the recharge water will firstly reach a thermal equilibrium state and then mix with the warmer base flow at deeper location, which is verified in a karst spring with anomalous event-scale temperature drops after rainfall events all year around. The thermal response simulations obtained from this work provide new ways and insights to characterize geographic structure of karst aquifer and elucidate heat transfer mechanism in karst aquifer systems. [ABSTRACT FROM AUTHOR]

In this study, the water level and temperature in the Sepidrood reservoir were simulated using CE-QUAL-W2 software. The utilized data for the calibration of water level and temperature models were the in-situ data from 1/6/2005 to 9/4/2006. Sensitivity analysis was used for determination of the influenced parameters on the water level and temperature in the Sepidrood reservoir. The results showed that wind sheltering coefficient, shading coefficient and empirical coefficients in the wind speed function are the most important parameters, hence these parameters were calibrated in the calibration step. In the validation step, the data from 9/4/2006 to 8/10/2006 were utilized. The results of model validation showed that CE-QUAL-W2 can simulate the water level and temperature with 0.3 and 3.6 % error, respectively. The results imply that the model has appropriate performance for water level and temperature simulation. The results demonstrated that Sepidrood reservoir is a completely mixed reservoir. The influences of different parameters on the reservoir stratification were investigated. The results demonstrated that the high wind speed and low retention time are the main factors on complete mixing of Sepidrood reservoir. In addition, the air temperature and the position of reservoir withdraw have no significant effects on the reservoir stratification.

A simulation has been developed for estimating the transient temperature and pressure distributions in a high-temperature superconducting (HTS) power cable with a fault current accident cooled by a forced flow of subcooled liquid nitrogen (LN2). This simulation is an essential tool for realizing a practical HTS power cable in order to assess the effects of short-circuit accidents. When a fault occurs in a 275 kV class power transmission system in Japan, an excessive current of 63 kA may flow in the cable for 0.6 s. When faults occur, it is important to estimate the temperature and pressure profiles in a cable cooled by the forced flow of subcooled LN2. The temperature profiles of the LN2 coolant and the cable cores were analyzed by solving nonlinear partial differential equations of the heat transfer phenomenon through heat conduction using finite-difference method. The GASPAK software package (Cryodata) was used to evaluate the fluid properties. The simulation results for 275 kV class 20 m model cable show fairly good agreement with the experimental results obtained by Fukukawa Electric. [ABSTRACT FROM PUBLISHER]

Accurate simulation of temperature effect is a major challenge for computational (intelligent) prediction models used for monitoring health of high concrete dams, especially in regions with long freezing periods and distinct seasons, occasional extreme weather. A Hydrostatic-Temperature long-term -Time (HT L T) model was proposed for better temperature effect simulation using long-term measured environment temperatures and explored the influence of temperatures data sets of different time lengths on dam displacement prediction accuracy with the traditional Hydrostatic-Season-Time model as control. The Bald Eagle Search algorithm was coupled with the Relevance Vector Machine to form a novel hybrid model (BES-RVM) for predicting concrete gravity dam displacement response and comparison of nonlinear mapping capability between different kernel functions was conducted. Further optimized by Successive Projections Algorithm (SPA) for feature selection, sensitive features were selected from the proposed HT L T variable sets to improve the prediction model's accuracy. The prediction model was experimented on a real concrete dam with results showing that the BES-RVM model gave excellent prediction performance. Using the HT L T variable sets significantly reduced the prediction errors and the best performed result came from variables of the two-year long temperatures data. The SPA optimized BES-RVM model largely brought down the dimension and the collinearity of the input variables and further improved the prediction performance. [ABSTRACT FROM AUTHOR]

White Etching Layers (WELs) on rails owe their name to the white appearance after etching with Nital. WEL is very often linked with rail defects like Squats and are said to partly consist of martensite, which indicates thermal effects. On this account, temperature simulations on and below the rail surface in the wheel-rail contact zone were done for a given set of parameters. The simulation results reveal that the austenitisation temperature of steel – necessary for the development of martensite – is reached under certain conditions. Validation tests on the full-scale wheel-rail test rig at voestalpine Schienen GmbH (Leoben / Austria) produced WELs and showed a good agreement with the simulation results. The presented and validated model can e.g. be used to enhance traction and braking control systems to reliably avoid the development of WELs in operation and to reduce according wheel-rail defects (e.g. Squats). [ABSTRACT FROM AUTHOR]

Consumption of cutting fluids imposes high costs on industries. Furthermore, they contaminate the environment and are harmful to human health. Minimum quantity lubrication technique (MQL) is an attractive alternative approach to reduce cutting fluids consumption, improve efficiency of cutting fluids at machining zone and use of harmless fluids. However, this technique faces cooling limitation in grinding. The first purpose of this study is a comprehensive investigation of heat transfer mechanism in MQL technique by its temperature numerical simulation. The second purpose is improvement of cooling ability of MQL air jet by using a simple and inexpensive vortex tube. To do this end, a system was designed and manufactured to measure the convection heat transfer coefficient of different conditions of cold air with MQL (CAMQL). The results of convection heat transfer tests show 95% share of compressed air in heat transfer. Also, the results indicate that air pressure is a more important factor than temperature in cooling process at high thermal power. The results of temperature numerical simulation show that by increasing pressure, the increasing rate of convection heat transfer coefficient decreases. Also, the temperature cooling ability of colder air with lower pressure is perceptible at low thermal power. In surface grinding of CK45 soft steel, CAMQL in comparison with dry and conventional fluid cooling leads to significant reduction of tangential grinding force and friction coefficient. But in general, except in the case of optimum condition which has the highest heat transfer coefficient, surface finish is worse. This is attributed to low heat transfer coefficient of gases at lower pressures. [ABSTRACT FROM AUTHOR]

The steady-state thermal conditions of district heating (DH) systems refer to temperature distribution from production plants to consumers. Mathematical models of such networks can be applied, either for general understanding of the system, or in combination with production planning and optimization. In this study, the DH system configuration was simplified to two basic elements (branches and nodes), and a novel matrix simulation model was proposed. Because of its matrix form, the thermal simulation model can be solved quickly by matrix operations. In addition, this new model can represent the whole structure of a large DH system, and it is therefore, easy to change or add new components to an existing model. However, due to the uncertainty of some model parameters, the differences between predicted and observed temperature are usually unacceptable. Therefore, model parameters require calibration before obtaining useful results from simulation. In order to solve this problem efficiently and precisely, the aggregated heat conduction coefficient of pipelines was developed, which could reduce the number of uncertain parameters significantly. Furthermore, an implicit calibration method was introduced, and it could transfer the calibration problem to a typical programming problem. The optimal parameters of this simulation model can be obtained by minimizing a nonlinear objective function subject to a set of linear constraints with the help of a powerful searching technique (genetic algorithms). Advanced MATLAB Genetic Algorithm Solver was used in order to help program process more convenient. Moreover, the validity of this implicit calibration method was demonstrated by the observed data from a real DH system in Harbin. For uncalibrated model, the average absolute error of supply temperatures at all substations was 1.4 °C. But for calibrated model I and II, the average absolute error of supply temperatures were only 0.2 °C and 0.1 °C, respectively. Therefore, the accuracy of temperature prediction enhanced significantly after calibration and the proposed optimization method was validated. [ABSTRACT FROM AUTHOR]

Water temperature dynamics in a reservoir are affected by its bathymetry, climatic conditions and hydrological processes. Miyun Reservoir in China is a large and deep reservoir that experienced a large water level decline in 1999–2004 due to low rainfall and relatively high water supply to Beijing. To study changes of stratification characteristics in Miyun Reservoir from 1998 to 2011, the one-dimensional year-round lake model MINLAKE2010 was modified by adding a new selective withdraw module and a reservoir hydrological model. Simulation results under three scenarios demonstrated that the new MINLAKE2012 model accurately predicted daily water levels and temperature dynamics during the water level fluctuation period. The water level decline led to 7.6 and 3.8°C increases in the maximum and mean bottom temperatures and about 29 days reduction in the stratification days. These simulation results provide an insight into the thermal evolution of Miyun Reservoir during the planned future water filling process.Editor D. Koutsoyiannis Associate editor M. Acreman [ABSTRACT FROM AUTHOR]

Inertial confinement fusion (ICF) mainly uses strong focus laser beams to irradiate the target to obtain sufficient energy. The ignition target is an essential factor for inducing a fusion reaction within a capsule. The cooling arm that connects the cooling source to the hohlraum is an important part of the ignition target, which is used to obtain an accurate and uniform temperature field for the deuterium-tritium ice pellet. To improve the temperature uniformity of the connecting surfaces between the cooling arm and the hohlraum, the cooling arm is designed to have a groove structure. On the basis of theoretical analysis and temperature simulation, the three-branch cooling arm was found to have a smaller temperature difference on the clamping surface and better mechanical strength than the cooling arm with fewer branches. Moreover, the fracture failure test shows that the fracture force of the three-branch cooling arm is 1.12 N, which is larger than that of the two-branch cooling arm. Because the smoothness of the connecting surface between the cooling arm and the hohlraum has a considerable effect on heat transfer, a KOH:isopropanol (IPA) solution is used to polish the rough deep reactive ion etching (DRIE) surface. [ABSTRACT FROM AUTHOR]

• An effective establishment of the gear temperature model is proposed. • A wireless gear temperature measuring system is developed. A systematic investigation on gear scuffing capacity under oil jet lubrication was presented numerically and experimentally. A sequence coupling numerical methodology was proposed for the effective establishment of the gear temperature model. A gear scuffing test under jet lubrication was designed and conducted, in which the gear temperature was measured via a developed wireless measuring system. The proposed testing method enables a quick evaluation of gear scuffing failure without frequently dismantling the gearbox. The simulated gear bulk temperature is compared with experimental results and shows consistency, the largest deviation between which during the whole gear scuffing test is 5.4%. The simulation model provides an efficient and reliable method for the evaluation of gear scuffing capacity. [ABSTRACT FROM AUTHOR]

To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they can be separated into two categories: capacitive components and resistive components. Then, the thermal-hydraulic pseudo-bond graphs of capacitive C element and resistance R element were developed, based on the conservation of mass and energy. Subsequently, the connection rule for the pseudo-bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing a piston pump, the lumped parameter mathematical model of the system was given. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method. [ABSTRACT FROM AUTHOR]

In this paper, we introduced parameterizations of the salinity effects (on heat capacity, thermal conductivity, freezing point and saturated vapor pressure) in a lake scheme integrated in the Weather Research and Forecasting model coupled with the Community Land Model (WRF-CLM). This was done to improve temperature simulation over and in a saline lake and to test the contributions of salinity effects on various water properties via sensitivity experiments. The modified lake scheme consists of the lake module in the CLM model, which is the land component of the WRF-CLM model. The Great Salt Lake (GSL) in the USA was selected as the study area. The simulation was performed from September 3, 2001 to September 30, 2002. Our results show that the modified WRF-CLM model that includes the lake scheme considering salinity effects can reasonably simulate temperature over and in the GSL. This model had much greater accuracy than neglecting salinity effects, particularly in a very cold event when that effect alters the freezing point. The salinity effect on saturated vapor pressure can reduce latent heat flux over the lake and make it slightly warmer. The salinity effect on heat capacity can also make lake temperature prone to changes. However, the salinity effect on thermal conductivity was found insignificant in our simulations. [ABSTRACT FROM AUTHOR]

Estimating end-use energy consumption that accurately reflects the variance of the end-load is critical for the grid wise simulation and analysis work. In a house, the largest load with a thermal cycle is often the heating ventilation and air conditioning (HVAC) system. So the thermal dynamics of typical residential electric air conditioner is discussed, and then an equivalent thermal parameters (ETP) model is built by the thermal equilibrium in this paper. Based on this, the switch status, indoor air temperature and power consumption are simulated through control strategies of constant thermostat set point. The results show according the switch status, indoor air temperature can be calculated by the ETP model, thus give the desire status to the grid according the setting temperature. In summer, with the increasing of setting temperature, the frequency of on-off becomes lower, thus the power consumption also reduces from 1200 kW (26 °C) to 970 kW (27 °C). So if some control strategies are used, the model will play an important part on decreasing the peak-average rate of the power grid and also improving the load rate of grid. [ABSTRACT FROM AUTHOR]

Purpose: In current clinical practice, head and neck (H&N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors' study is to investigate the relevance of using MRI in addition to CT for patient modeling in H&N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H&N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRIdb). To quantify the relevance of MRI based segmentation for H&N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (Tmax) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRIdb. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm). Patient models based on CT (W 38.0 °C) and CT and MRI (Tmax: 38.1 °C) result in similar simulated temperatures, while CT and MRIdb (Tmax: 38.5 °C) resulted in significantly higher temperatures. The SAR corresponding to these temperatures did not differ significantly. Conclusions: Although MR imaging reduces the interobserver variation in most tissues, it does not affect simulated local tissue temperatures. However, the improved soft-tissue contrast provided by MRI allows generating a detailed brain segmentation, which has a strong impact on the predicted local temperatures and hence may improve simulation guided hyperthermia. [ABSTRACT FROM AUTHOR]

• A shade net improves thermal performance of the Standard Family Tent (SFT). • The Geodesic Family Tent (GFT) has similar thermal performance to the shaded-SFT. • Practical advantages of the GFT could improve emergency living conditions. Humanitarian tents provide emergency shelter for people displaced by conflict and disaster in diverse climatic conditions. This article compares the thermal performance of two standard humanitarian tents – the Standard Family Tent (SFT) and the Geodesic Family Tent (GFT). The SFT is the most widely used humanitarian shelter, while the GFT was recently introduced as a potential replacement intended to provide, inter-alia , improved thermal performance. The study aims to assess the extent to which this intention is achieved and, in doing so, improve understanding about how tent material and morphology affect thermal performance. Several variables, including internal air temperature, surface temperature, relative humidity and air change rates, were measured and compared in hot and cold conditions. Results demonstrate that the GFT performs better than the SFT regarding radiant heat gain, conductive heat loss and increased air tightness. However, performance of the GFT in relation to heat gain and heat loss is similar to that of the SFT with an additional shade net. Other functional advantages of the GFT are improved structural stability and spaciousness, which, together with improved thermal performance, suggest this marginal innovation in shelter design can positively impact emergency shelter living conditions. [ABSTRACT FROM AUTHOR]

Abstract: In the simulation of waxy oil–gas pipeline multiphase flow, the physical parameters and rheological properties of the multiphase fluid are the sensitivity functions of the temperature. The precise temperature distribution of multiphase fluid is the foundation of predicting the pressure distribution accurately, wax deposition rate, optimized design and operating analysis of waxy oil and gas pipeline, and so on. Based on the energy equation of oil–gas flow in pipeline, the explicit temperature drop formula (ETDF) for oil–gas steady state calculation is derived from the energy conservation analysis in micro-element. This new energy equation has considered many factors, such as heat transfer with the surroundings along the line, Joule–Thomson effect and impact of terrain undulation to potential energy. So it is an overall form of energy equation, which could reflect the actual fact of multiphase pipeline accurately. Elimination of temperature iteration loop and integration of the explicit temperature equation, instead of enthalpy energy equation, into the conjugated hydraulic and thermal computation have been found to improve the efficiency of algorithm. The calculation program of temperature drops of waxy oil–gas flow in pipelines is compiled on the basis of the ETDF employing modification of the specific heat of the waxy oil. This model is carried out with a practical waxy oil–gas two phase flow pipeline, and the temperature results are compared with OLGA. It is shown that this model has simulated the temperature distribution very well. [Copyright &y& Elsevier]