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During the operation of the compressor station where the centralized air after-cooling mode is adopted, the uncooled hightemperature natural gas from the discharge of compressor enters the suction of compressor through the anti-surge pipeline after the anti-surge valve is opened, and then the natural gas is subjected to the repeated cyclic pressurization in the compressor, resulting in obvious temperature rise. During the operation of the unmanned station, there are problems of untimely handling of such phenomenon, which affects the normal operation of the compressor and shortens the life of the pipeline coating. Herein, the causes and effects of circulating temperature rise were analyzed, and it was proposed to open the circulation valve in the station by control to an appropriate opening, further to close the anti-surge valve of the compressor and solve the problem of circulating temperature rise. Therefore, the PI control with dead band was proposed to control the opening of the circulation valve in the station, and the conditions for opening the circulation valve in the station, the target value of PI control and the relevant control parameters were also set. It is verified through operation that the circulating temperature rise after the opening of anti-surge valve of the compressor under the condition of centralized air after-cooling process is effectively controlled, capable of ensuring the safe operation of the compressor station. Generally, the research results could provide guidance for the automatic control of the circulation valve in the compressor station in the centralized air after-cooling mode, laying a foundation for the construction of the unmanned station.

Thin-film beam combining technology is an effective approach to improve output power while maintaining beam quality. However, the lack of comprehensive research into the key factors affecting the beam quality in systems makes it challenging to achieve a practical combined beam source with high brightness. This paper clearly established that the temperature rise of dichroic mirrors (DMs) and sub-beam overlapping precision are the main factors affecting the beam quality of the system, with quantified effects. Based on this understanding, a combined light source of four channels of 3 kW fiber lasers was achieved, and an output power of 11.4 kW with a beam quality of M2 x = 1.601 and M2y = 1.558, using three high-steepness low-absorption DMs and the active control technique. To the best of our knowledge, this is the best beam quality for a 10 kW light source. This study offers a solution for practical high-power laser sources in the tens of kilowatts range.

One limitation on the ability to monitor health in older adults using magnetic resonance (MR) imaging is the presence of implants, where the prevalence of implantable devices (orthopedic, cardiac, neuromodulation) increases in the population, as does the pervasiveness of conditions requiring MRI studies for diagnosis (musculoskeletal diseases, infections, or cancer). The present study describes a novel multiphysics implant modeling testbed using the following approaches with two examples: (1) an in silico human model based on the widely available Visible Human Project (VHP) cryo-section dataset; (2) a finite element method (FEM) modeling software workbench from Ansys (Electronics Desktop/Mechanical) to model MR radio frequency (RF) coils and the temperature rise modeling in heterogeneous media. The in silico VHP-Female model (250 parts with an additional 40 components specifically characterizing embedded implants and resultant surrounding tissues) corresponds to a 60-year-old female with a body mass index of 36. The testbed includes the FEM-compatible in silico human model, an implant embedding procedure, a generic parameterizable MRI RF birdcage two-port coil model, a workflow for computing heat sources on the implant surface and in adjacent tissues, and a thermal FEM solver directly linked to the MR coil simulator to determine implant heating based on an MR imaging study protocol. The primary target is MR labeling of large orthopedic implants. The testbed has very recently been approved by the US Food and Drug Administration (FDA) as a medical device development tool for 1.5 T orthopedic implant examinations.

Anthropogenic climate change is projected to affect marine ecosystems by challenging the environmental tolerance of individuals. Marine fishes may be particularly vulnerable to emergent climate stressors during early life stages. Here we focus on embryos of Pacific herring (Clupea pallasii), an important forage fish species widely distributed across the North Pacific. Embryos were reared under a range of temperatures (10-16°C) crossed with two pCO2 levels (600 and 2000 μatm) to investigate effects on metabolism and survival. We further tested how elevated pCO2 affects critical thermal tolerance (CTmax) by challenging embryos to short-term temperature fluctuations. Experiments were repeated on embryos collected from winter and spring spawning populations to determine if spawning phenology corresponds with different limits of environmental tolerance in offspring. We found that embryos could withstand acute exposure to 20°C regardless of spawning population or incubation treatment, but that survival was greatly reduced after 2-3 hours at 25°C. We found that pCO2 had limited effects on CTmax. The survival of embryos reared under chronically warm conditions (12°, 14°, or 16°C) was significantly lower relative to 10°C treatments in both populations. Oxygen consumption rates (MO2) were also higher at elevated temperatures and pCO2 levels. However, heart contraction measurements made 48 hours after CTmax exposure revealed a greater increase in heart rate in embryos reared at 10°C compared to 16°C, suggesting acclimation at higher incubation temperatures. Our results indicate that Pacific herring are generally tolerant of pCO2 but are vulnerable to acute temperature stress. Importantly, spring-spawning embryos did not clearly exhibit a higher tolerance to heat stress compared to winter offspring.

Superconducting bulks applied to high-temperature superconducting (HTS) maglev vehicles are susceptible to magnetic field, resulting in alternating current (AC) losses and heat generation, which affect the stability of the suspension system. Therefore, the thermal effect of superconducting bulk under external magnetic field is worth studying. The paper uses finite element software to establish a 2D electromagnetic-thermal coupling model. The distribution and variation of HTS bulks' temperature under varying external magnetic field are simulated and analyzed, and the loss and temperature rise of rectangular bulks with different thicknesses are studied. Finally, the effect of increasing the critical current density on the thermal effect of the superconducting bulk is discussed. The results show that the temperature rise of bulk has a positive correlation with the amplitude and frequency of external magnetic field. The maximum temperature is affected by the angle of magnetic field. Under the same external magnetic field, the bulk with smaller thickness produces smaller loss and temperature rise. The research results can provide important references for the operation and furniture design of HTS maglev vehicles. [ABSTRACT FROM AUTHOR]

With the development of eddy current brake (ECB), they are widely used in life and military. Through the ECB, the resistance is converted into thermal energy and dissipated in the air. Thermal energy will make the temperature rise and the heat cannot be dissipated quickly. The electromagnetic characteristics of many parts in the ECB are very sensitive to temperature. Therefore, the study of temperature field is very important for it. This paper takes the linear cylindrical ECB as an example to study the heat generated under the intense impact and high speed condition. The temperature field is calculated through finite element method (FEM) ways. According to the temperature distribution characteristics, the cooling measures of permanent magnet brake are studied to effectively reduce the temperature rise of the brake, ensuring its reliability. [ABSTRACT FROM AUTHOR]

Copyright of Large Electric Machine & Hydraulic Turbine is the property of Large Electric Machine & Hydraulic Turbine 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 aim of this research is to predict the effects of future climate change on cotton yield in Birjand region. In this research, the BCM2 general circulation model under two release scenarios B1 and A1B in three periods (2025 to 2050, 2050 to 2075, and 2075 to 2100) was examined to predict future climate conditions and to generate daily climate parameters of the LARS-WG microscale model. Daily climate data obtained from LARS-WG output were used as inputs for DSSAT model (crop simulation model) to simulate cotton growth under future climate. The selection and preparation of a suitable plot of land for the implementation of the project was done in the beginning of October 2018. The intended experimental design was factorial split plots. The DSSAT model provided acceptable results for cotton yield and phenological stages, and this success was confirmed when the values simulated by the model were compared with the data collected from the field experiments. The maximum NRMSE is related to HW simulation, which is calculated as 9.7%. The value of this index for simulating the phenology stages is much lower and its value is reduced to 1.5%. The results of this research show that the DSSAT model can be a promising tool for predicting yield, leaf area, nitrogen accumulation, phenology and biomass of different cotton cultivars and other crops grown in the region. It seems that this study is useful and appropriate for farmers and their making decisions. The results of the simulations showed that due to future climate change and increase in temperature and carbon dioxide concentration in Birjand city, cotton yield will increase. On average, under all scenarios, the average yield of cotton will increase by 15% in the period of 2025 to 2050, by 15.44% in the period of 2050 to 2075 and by 18.15% in the period of 2075 to 2100. The simulation has shown that climate change increased cotton yield (from 14.73 to 18.53 percent) and reduced the length of the cotton growing season. The main reason for the increase in cotton yield can be attributed to the increase in carbon dioxide concentration. [ABSTRACT FROM AUTHOR]

This study aimed to compare the temperature changes occurring on the root surfaces after the removal of root canal filling with two different root canal sealers by two different reciprocating files. Sixty extracted teeth with a single root and canal were used in this study. After chemomechanical preparation, the root canals in the experimental groups were filled with gutta-percha and AH Plus or CeraSeal, while those of the control groups were filled with gutta-percha only. Resiproc or WaveOne Gold were used for the removal of the root canal filling. Temperature changes in the middle and apical third of the root surface were recorded by a thermal camera at different time intervals. Among the groups using the same sealer, the temperature rise observed on the root surface at the end of 90 s in the Resiproc groups was found to be significantly higher than that of the WaveOne Gold groups. [ABSTRACT FROM AUTHOR]

Accurate temperature rise prediction of the gas‐insulated transmission lines (GIL) can help to lower the cost of equipment through optimization design. To investigate the temperature rise of GIL and the heat transfer efficiency of new eco‐friendly insulating gas, the electromagnetic‐thermal‐fluid field coupling method that considers the thermal properties of solid and gaseous media is proposed. The finite element method is applied to solve the eddy‐current field and obtain the Joule loss of the conductive rod and the enclosure accurately. The GIL temperature distribution of different insulating gases is computed based on their thermophysical parameters. The heat transfer efficiency is found to be positively correlated with gas density, constant pressure heat capacity and thermal conductivity. A parameter that characterizes the heat transfer efficiency of the insulating gas is defined, such that a larger value indicates a higher heat transfer efficiency. This parameter helps to quickly determine the heat transfer capacity of new eco‐friendly insulating gas, and facilitate the optimal design of GIL equipment. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The paper address the impact of an increase in the carbon dioxide concentration, surface air temperature and a change in a degree of climate continentality on the yield of spring wheat for the territory of Russia and for three grain-producing regions: the Saratov and Chelyabinsk oblasts and the Altai krai. The studies were based on the correlation, variance, and multiple regression analyses. The significance of the influence of the selected factors on the spring wheat is determined both for the territory of Russia and for individual regions. The influence of the degree of climate continentality on the spring wheat grain quality (protein content) in the Saratov oblast is assessed. [ABSTRACT FROM AUTHOR]

The mesoscale effect of climate change and engineering activities on a superficial frozen soil–rock mixture (FSRM) in regions is complex. The decrease in strength caused by particle ice film ablation under temperature rise has various effects, such as upper subgrade settlement deformation. However, the internal mechanism of FSRM strength degradation remains unclear. Triaxial and nuclear magnetic resonance tests on FSRM were performed at various temperatures to clarify the mechanism of FSRM internal degradation. The results show that the strength, cohesion, and internal friction angle of FSRM decrease with increasing temperature, and the attenuation is significant in the range of −5 to 0°C. The change in ice–water content can be divided into three stages (i.e., freezing, phase transformation, and complete melting). In the three stages, the maximum free water is only 24%, while the maximum bound water is 100% above 0°C. Based on the microscopic test results, a mesoscopic calculation model for FSRM particles was developed. It was found that the work between particles is consistent with the law of strength degradation, and the friction function by particles gradually changes to bite work with increasing temperature. By introducing the strain energy theory, the strain energy generated by particle shear work is considered the key index to reflect FSRM strength. The particle ice film locking effect is weakened under temperature rise, and the increase in water weakens the strain energy generated by the work of the bite friction between particles during the shear process. At the macro level, the strength of FSRM deteriorates. [ABSTRACT FROM AUTHOR]

Over the past 50 years, climate change has threatened both existing and imminent pavement infrastructure. It is also forecasted to become more aggressive in the future. Therefore, pavement design procedure needs to be adapted accordingly, accounting for the climate change factors. The current study explores the projected climate change in Newfoundland using various climate change models. In addition, this study aims to quantify the influence of climate change on pavement design in Newfoundland and Labrador Province, Canada. To achieve that, a robust mechanistic-empirical pavement design tool (AASHTOWare ME Pavement Design) was used. A statistically downscaled climate change models were extracted from the coordinated regional downscaling (CORDEX) Experiments to predict the future climate. Then the minimum and maximum daily temperatures for five different locations in Newfoundland were extracted using a python code. However, there is a challenge to convert these daily temperatures into hourly temperatures. Therefore, two relatively new hourly data estimation procedures, such as the modified imposed morphing method (M-IOMM) and Sine (14R-1) were used. These hourly estimated data were utilized to further predict the pavement performance for all the five locations in Newfoundland, Canada. This study concludes that climate change accelerates pavement deterioration compared to baseline climate. [ABSTRACT FROM AUTHOR]

Copyright of Large Electric Machine & Hydraulic Turbine is the property of Large Electric Machine & Hydraulic Turbine 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.)

Temperature rise of the hub motor in distributed drive electric vehicles (DDEVs) under long-time and overload operating conditions brings parameter drift and degrades the performance of the motor. A novel online parameter identification method based on improved teaching-learning-based optimization (ITLBO) is proposed to estimate the stator resistance, ��-axis inductance, ��-axis inductance, and flux linkage of the hub motor with respect to temperature rise. The effect of temperature rise on the stator resistance, ��-axis inductance, ��-axis inductance, and magnetic flux linkage is analysed. The hub motor parameters are identified offline. The proposed ITLBO algorithm is introduced to estimate the parameters online. The Gaussian perturbation function is employed to optimize the TLBO algorithm and improve the identification speed and accuracy. The mechanisms of group learning and low-ranking elimination are established. After that, the proposed ITLBO algorithm for parameter identification is employed to identify the hub motor parameters online on the test bench. Compared with other parameter identification algorithms, both simulation and experimental results show the proposed ITLBO algorithm has rapid convergence and a higher convergence precision, by which the robustness of the algorithm is effectively verified. Keywords: parameters identification, teaching–learning-based optimization, hub motor, temperature rise.

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology 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.)

Dynamic behavior of armor steel grade has been investigated by implementing Johnson-Cook plasticity and failure models. The stress and strain curves obtained from the experiments at different strain rates (10−4-1550 s−1) and temperatures (25-600 °C) were used to calibrate the parameters of Johnson-Cook plasticity model. Parameters of Johnson-Cook failure model were obtained by combining finite element modeling with tensile tests. Validation of Johnson-Cook material parameters is performed using finite element simulations and digital image correlation experiments performed on notch specimens of radii between 2 and 6 mm under uniaxial tension. The ballistic impact tests were performed on 6 mm thick armor plate against 7.62 × 39 mm hardened steel core and 7.62 × 54 mm armor-piercing projectiles. The armor plate when impacted against 7.62 × 39 mm projectile exhibits indentation, while the plate undergoes complete penetration when impacted against 7.62 × 54 mm projectile. Results of ballistic tests at different incident velocities were compared by carrying out numerical simulations on armor steel plate. The ballistic limit of the plate, when impacted against 7.62 × 54 mm projectile, is obtained from numerical simulation and estimated as 825 m/s. The plate experiences a high strain rate and hence a temperature rise during the impact. The present work investigates the increase in temperature in the plate during the ballistic impact at different incident velocities. The temperature of the plate was estimated to increase up to half of its melting temperature, 810-952 K, when impacted against the 7.62 × 54 mm projectile at varying velocities between 820 and 950 m/s. [ABSTRACT FROM AUTHOR]

Due to increasing single unit capacity and large-capacity of each pole, the unit volume loss of excitation winding of the pumped storage power generation/motor elevates accordingly, which may give rise to the damage of turn-to-turn insulation. When the damage developed to some degree, the turn-to-turn short-circuit and the burned excitation winding can occur, impacting security and stability considerably. To address this problem, the reasonable arrangement of heat dissipation turns in excitation winding is investigated, aiming to improve the cooling capacity. Taking a pumped storage power generator/motor with large capacity of 277.8 MVA (generator condition)/286.4 MVA (motor condition) and rotating speed of 250 rpm as an example, the fluid–solid coupled heat transfer equations are established, and the solution domain, boundary conditions and assumptions are given. Through the comparison and analysis of the calculated results of the temperature parameters of the excitation winding with different cooling structure types, the reasonable structure type is thoroughly investigated. Based on the genetic optimization algorithm, the value scope of W parameter related to temperature non-uniformity coefficient, temperature rise of the excitation winding and copper cost is determined, which is taken as the basis for comprehensive judgment. Additionally, the simulation results show good agreement with the measured data validating the theoretical calculation method. [ABSTRACT FROM AUTHOR]

This study aimed to assess the light transmittance (T) and temperature increase through different increments of dual-cure bioactive bulk-fill restorative material (ACTIVA), light-cure bulk-fill, and conventional composite resin materials. Cylindrical specimens with a diameter of 8 mm and heights of 1, 2, 3, and 4 mm of ACTIVA, Tetric-N-Ceram bulk-fill (TBF), Filtek One bulk-fill (FBF), and Filtek Z250 (FZ) (n = 6 per group, 96 in total) were light-cured with a visible blue low-intensity light-emitting diode (LED) (650–800 mW/cm2 irradiance). T, and the temperature increase, were measured using an optical power meter and a digital thermometer during curing. The T mean values ranged between 0.012 and 0.239 (76.02 to 98.81% light attenuation), while the temperature rise mean values ranged between 9.02 and 20.80 °C. The parameters, including material type (partial eta squared (ηp2) = 0.284, p < 0.0001), thickness (ηp2 = 0.284, p < 0.0001), and their interaction (ηp2 = 0.185, p = 0.047), significantly affected the T values, whereas only the material type (ηp2 = 0.352, p = 0.047) affected the temperature rise values. The T and temperature rise mean values were highest in ACTIVA increments of 1-mm increments, in particular, showing the highest T mean values, followed by similar increments of TBF. A significantly higher T was found in 1-mm increments compared to thicker increments for all materials (p < 0.0001), and a significant positive correlation existed between T and temperature rise values (r = 0.348, p = 0.001). These findings show that the bioactive material ACTIVA and TBF allow for better T than the other materials, with ACTIVA recording a higher temperature rise. However, the large light attenuation observed for all materials, irrespective of thickness, suggests that curing in more than one location with a low-intensity LED is necessary to optimize the curing process. Furthermore, incremental filling of bulk-fill materials using a low intensity LED could be beneficial. [ABSTRACT FROM AUTHOR]

Dealing with the conflict between the temperature/pressure rise and the total mass of hydrogen is a key challenge for rapid hydrogen filling of the hydrogen storage tank (HST). The temperature/pressure rise and total mass of hydrogen cause safety risks because of the former and limited cruise as the result of the latter. Therefore, safe hydrogen filling strategy is essential for the promotion of hydrogen fuel cell vehicles (FCVs). The existing thermodynamic model of the hydrogen storage tank is simplified either in the hydrogen state or the heat conduction of the HST wall, which can be hardly used as the real-time and accurate references for developing the filling strategy. To solve this problem, this paper works out the mathematical expression of a HST thermodynamic model. With the proposed HST thermodynamic model, a variable mass flow hydrogen filling strategy is developed. The results show that at the mass flow (12 g/s), the errors of the thermodynamic model are 7.1% and 6.8% for the temperature and pressure rise, compared with the computational fluid dynamics (CFD) model. At the mass flow (4.84 g/s), the thermodynamic model errors are 8.3% and 7.1% for the temperature and pressure rise, compared with the experimental data. Also, compared with the rule-based hydrogen filling strategies, the final state of charge (SoC) with the new filling strategy improve by 3%, 3.7%, and 2.7% at different initial temperatures, different volumes, and initial SoCs, respectively. • A real-time thermodynamic HST model with strong convergence is proposed. • The wall's unsteady heat transfer and hydrogen real properties are considered. • Variable mass flow is applied in the development of the filling strategy first. • The mass flow is determined by reinforcement learning, not rule-based. [ABSTRACT FROM AUTHOR]

A sand-coated solar air collector (SCSAC) is simulated and optimized using an integrated expert technique fuzzy C-Means Takagi–Sugeno–Kang fuzzy logic technique for order preference by similarity to ideal solution (FCM-TSK-FL-TOPSIS) for climatic conditions of Bangalore rural, Southern part of India. In this study, the FCM method was used to cluster the experimental dataset, and TSK-FL is used to predict the optimal experimental data, while TOPSIS is applied in order to optimize SAC input and output parameters. Different governing characteristics are taken into account as input parameters, such as air mass flow rate, collector tilt angle, solar radiation, and ambient temperature, while thermal efficiency, temperature rise, and pressure drop are output parameters. Initially, the input parameters of a sand-coated SAC are varied in order to conduct experiments. Finally, results are revealed from the integrated method for sand-coated SAC experimental optimal input setting as 0.010 kgs−1 mass flow rate, 933.7 Wm−2 solar radiation, 35.33 °C temperature inlet and corresponding output optimal parameters such as temperature rise is 61.4 °C, energy efficiency 34.48%, and pressure drop of 6.86 Pa. This integrated method is beneficial for researchers who are engaged in the optimization of solar thermal systems and industries applications which involve drying, heating, etc. [ABSTRACT FROM AUTHOR]

Four different experimental approaches for rapid estimation of fatigue limit (endurance limit) based on energy dissipation during cyclic loading are discussed. The presented approaches use energy dissipation and thermography and can reliably evaluate the fatigue limit of material by conducting the fatigue test on a single specimen. Results show that the released energy due to damage accumulation at the stress levels above the fatigue limit changes the trend of energy dissipation and that this trend can be used to predict the fatigue limit. Experimental results on CS 1018 and SS 304 specimens are presented to illustrate the utility of the proposed methods. Highlights: Metal fatigue endurance limit can be rapidly measured using energy dissipation.Four different experimental approaches for measuring endurance limit are presented.Endurance limit results are verified for CS 1018 and SS 304 by conventional fatigue testing.Thermography methods offer a viable approach for determining fatigue limit. [ABSTRACT FROM AUTHOR]

The present investigation endeavored to understand trends in climatic, hydrological, and agricultural variables in the five semi-arid river basins of Maharashtra (India). For this, parametric and non-parametric statistical techniques were applied. The monsoon rainfall over the study area reveals no considerable increase during the past (1981–2013) and future (2020–2050). Although the construction of a large number of impoundment structures during the last two decades resulted in a significant rise in post-monsoon groundwater table (by 40 cm/decade), it caused a decline in surface runoff. The study area witnessed a significant increase in area under irrigated crops at the cost of rainfed crops, which resulted in a significant increase in groundwater withdrawal (GWW) by 70 cm/decade. The cropped area and productivity of irrigated crops heavily depend on rainfall and groundwater resources. Moreover, the Southern Oscillation Index (SOI) has a positive connection with the productivity of irrigated crops. On the other hand, a considerable increase in annual minimum temperature (AMNT), annual maximum temperature (AMXT), and annual mean temperature (AMT) (by 1.02, 0.50, and 0.82 °C, respectively) along with a rise of > 100 mm in potential evapotranspiration (PET) is registered during 1985–2015. The study indicates that the irrigated crops are more vulnerable to heat stress, as PHS (plant heat stress with > 34 °C) days show a considerable increase (2–5 days/decade). Furthermore, the climate projection suggest a significant rise of 1.05 °C in AMT by 2050, which is very likely to intensify the hydro-meteorological droughts and adversely affect the agricultural productivity of rainfed and irrigated crops as well. Briefly, the human-induced changes in cropping patterns (without a considerable increase in rainfall/water resource) from one side and the climatic changes (including extreme events) on the other side may exacerbate the regional water scarcity and food security challenges in the semi-arid region of Maharashtra (India) in the near-term future. [ABSTRACT FROM AUTHOR]

Over the past decades there has been a strong evidence of a temperature rise across the world that has led to a growing concern of more extreme weather patterns and regular seasonal heat waves globally. As such, building occupants are at a continuously growing risk to overheating exposure inside the premises throughout the warm season of the year. This study investigates the utilization of cooling pad technology as a potential solution to enhance cooling efficiency. Compared to traditional cooling methods, the implementation of cooling pads leads to significant reductions in temperature and enhanced humidity control, while consuming relatively lower amounts of energy. The study contains a comprehensive analysis of the climatic conditions in Latvia, focusing on temperature and humidity variations throughout the year over the last decade in three cities–Riga, Daugavpils and Liepaja, that extensively represent the scope of climatic variations across Latvia, featuring coastal and continental climate patterns. This study aims to evaluate the effectiveness and suitability of cooling pad technology in Nordic climate, focusing on three Latvian cities. The novelty of the study lies in its analysis of cooling pad technology’s effectiveness in Nordic climatic conditions in addressing the increasing cooling demand. The paper examines the fundamental principles behind cooling pad technology, its impact on chiller performance, and its ability to optimize the cooling process. The utilization of cooling pad technology as an effective means to enhance cooling efficiency across the building stock to improve occupant comfort level and IEQ is highlighted. The results demonstrate 5.47% COP increase during average summer temperature conditions, and 17.78% COP increase in peak summer temperature conditions after implementation of cooling pads. This study contributes to the existing knowledge on cooling technologies, offering practical recommendations for the implementation of cooling pad systems use in Latvia and across the wider Nordic region, which is experiencing the gradual rise in summer temperature and humidity level.

Under certain circumstances, a high-speed railway may require constant acceleration or emergency braking, in which case the inverter may experience short-term overload conditions and the current passing through the IGBT will go beyond the rated design tolerance. Under overload conditions, the IGBT loss will increase instantly, raising the power semiconductor device’s junction temperature in the process. This research examines the boosting-gate-voltage-driven IGBT control technology. It increases the gate drive voltage and the IGBT current capacity and decreases the conduction voltage drop of IGBT under short-term overload conditions, reducing the instantaneous loss and temperature rise undulation of IGBT. The working characteristics of IGBT devices are studied, and the influence of gate drive voltage on device loss and temperature rise fluctuations is analyzed. Based on the emergency acceleration and brake conditions of the actual train operation, the short-term overload characteristics of the inverter are analyzed. The optimization analysis of the boosting gate voltage under emergency conditions is carried out, and the IGBT drive circuit with gate voltage pumping function is designed. The effectiveness of the driving circuit is verified through PSpice simulation and actual switching characteristic test. According to the analysis of experimental data, it can be verified that increasing the gate voltage technology can reduce IGBT losses.

The traction motor is a crucial component of high-speed electric multiple units, and its operational reliability is directly impacted by the temperature increase in the bearings. To accurately predict and simulate the temperature change process of traction motor bearings during operation, a fluid–solid–thermal simulation analysis model of grease-lubricated deep groove ball bearings was constructed. This model aimed to simulate the temperature rise of the bearing and the grease flow process, which was validated through experiments. The results from the simulation analysis and tests indicate that the temperature in the contact zone between the bearing rolling element and the raceway, as well as the ring temperature, initially increases to a peak and then gradually decreases, eventually stabilizing once the bearing’s heat generation power and heat transfer power reach equilibrium. Furthermore, the established fluid–solid–thermal coupling simulation analysis model can accurately predict the amount of grease required for effective lubrication in the bearing cavity, which stabilizes along with the bearing temperature. The findings of this research can serve as a theoretical foundation and technical support for monitoring the health status of high-speed EMU traction motor bearings.

The highly complex contact interface phenomena require analysis at different length scales ranging from nanometer up to nearly centimeter scales. When two nominally smooth surfaces are brought into contact, solid-solid interaction across their contact interface is confined at multiple protrusions (asperities) of various shapes and sizes. The deformation mechanisms encountered at the asperity level control the surface conformity, which, in turn, influences the transmission of traction, heat, and electric current across the contact interface. Thus, the multiscale roughness of real surfaces necessitates the advance of methodologies and contact models that bridge the spectrum of relevant length scales. Rough surfaces have been traditionally characterized by statistical parameters, which cannot be uniquely determined because they depend on the sampling interval and the resolution of the measuring device. On the contrary, the scale-invariant parameters employed in fractal geometry provide an unbiased representation of the surface topography. This article provides an appraisal of the multiscale mechanical, thermal, and electrical characteristics of rough contact interfaces demonstrating fractal behavior. Theoretical treatments of elastic, elastic-plastic, and fully plastic deformation, heat conduction, temperature rise, and electrical contact resistance are presented for contact interfaces characterized by fractal geometry, providing a fundamental basis for developing multiscale thermo-electro-mechanics analytical treatments for contacting solid bodies.

Purpose: To investigate the temperature changes in pulp chamber of incisor and canine teeth during different stripping procedures with thermal imaging.Materials and Methods: Intact and freshly extracted human permanent 40 maxillary lateral incisor, 40 mandibular canine and 40 mandibular incisor teeth were selected for this study. Diamond bur, tungsten carbide bur and perforated diamond-coated disc were used for interdental stripping in high and low speed handpieces by air and water cooling. Temperature changes and cooling time of the tooth groups were recorded by a thermal imaging system. Paired t test and one-way analysis of variance (ANOVA) tests were performed for intragroup and intergroup comparisons of temperature changes and cooling time values.Results: Stripping procedures created a statistically significant temperature rise in all study groups (p < 0.05). For maxillary lateral incisors and mandibular incisors, the greatest temperature rise was calculated during stripping with tungsten bur and perforated disk under air cooling (p < 0.001), while no statistically significant difference was found between the temperature rise values of mandibular canine teeth during different stripping procedures (p = 0.053). The lowest temperature rise and cooling time values among all tooth groups were observed during stripping with diamond bur under water cooling and the longest cooling time values were detected during stripping with perforated disc under air cooling (maxillary incisor; p < 0.001, mandibular incisor; p < 0.05, mandibular canine; p < 0.05).Conclusion: For all tooth groups, stripping with diamond bur in a high speed handpiece under water cooling produced the lowest temperature rise in the pulp chamber and the shortest cooling time values among different stripping procedures. [ABSTRACT FROM AUTHOR]

This paper studies temperature rise characteristics of 110 kV XLPE cable under different service years. When the load is 900 A, the maximum temperature of the cable under 0, 15 and 30 service years is 335.5 K, 372.96 K and 393.88 K respectively. Compared with the data obtained from non-aged cable, the temperature increase for samples operating for 15 and 30 years is 111.15% and 117.4% higher. For these samples, the proportion of heating due to cable dielectric loss is 2.77%, 25.45% and 34.78%. The research content of this paper provides a basis for the research on the optimal current carrying capacity of cables with different service years, provides a reference for the actual application of cables, and has guiding significance for the research on prolonging the service life of cables and improving the utilization rate of cable resources.

For permanent magnet linear synchronous motor (PMLSM) working at trapezoidal speed for long time, high thrust brings high temperature rise, while low thrust limits dynamic performance. Thus, it is crucial to find a balance between temperature rise and dynamic performance. In this paper, a velocity planning model of the PMLSM at trapezoidal speed based on electromagnetic-fluid-thermal (EFT) field is proposed to obtain the optimal dynamic performance under temperature limitation. In this model, the winding loss is calculated considering the acceleration and deceleration time. The loss model is indirectly verified by the temperature rise experiment of an annular winding sample. The actual working conditions of the PMLSM are simulated by dynamic grid technology to research the influence of acceleration and deceleration on fluid flow in the air gap, and the variation rule of the thermal boundary condition is analyzed. Combined with the above conditions, the temperature rise of a coreless PMLSM (CPMLSM) under the rated working condition is calculated and analyzed in detail. Through this method and several iterations, the optimal dynamic performance under the temperature limitation is achieved. The result is verified by a comparison between simulation and prototype tests, which can help improve the dynamic performance.

This study used innovative testing methods to investigate the effect of physical temperature rise on low-speed friction torque of double nut ball screws. 72 experiments were conducted using two samples and three protocols. Found the inflection point temperature and inflection point velocity. Below the inflection point temperature, the frictional torque increases with the increase of speed; Above this temperature, the frictional torque first decreases and then increases. Below this inflection point speed, the frictional torque first decreases and then increases; Above the inflection point velocity, the friction torque decreases with increasing temperature. Based on the Strebeck theory, the variation of friction coefficient with temperature was studied; When it is below the inflection point speed, it fluctuates greatly with the increase of temperature, but when it is above the inflection point speed, the fluctuation is small and steadily decreases with the increase of temperature. In addition, based on the theoretical models of Coulomb friction torque and viscous friction torque, the results of this model are in good agreement with the measurement results above the inflection point speed, indicating the correctness of the theory and providing good theoretical guidance for engineering designers.

There is mounting evidence that, unless greenhouse gas (GHG) emissions fall back quickly, the goals outlined by the 2015 Paris Agreement to keep the global temperature rise well below 2 °C and preferably 1.5 °C will not be met. In response to these concerns, direct air carbon capture and storage (DACCS) technologies are gaining research and development attention. This article provides a thorough comparison of the two leading DACCS variants and reports on their status among major research and policy institutions worldwide. By translating the operating and capital costs to the Australian context, we assess the viability of DACCS implementation using either cheap renewable or legacy fossil energy to power CO2 extraction plants. [ABSTRACT FROM AUTHOR]

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The term "over-skidding" indicates that the cage rotational speed ratio exceeds the theoretical value as ball purely rolls on the raceway. Different from the skidding phenomenon that occurs in low-load and high-speed bearing, over-skidding usually occurs in large-size angular contact bearings, and it is still difficult to suppress under high load conditions. The main forms of damage to the raceway by over-skidding are spinning and gyro slip. To further explore the vibration characteristics and thermal effects of this phenomenon, a set of over-skidding tests of an angular contact bearing with a bore diameter of 220 mm were conducted on an industrial-size test bench. Through the experiment, the influence of axial load, rotational speed, and lubrication conditions on the occurrence of over-skidding were determined. Based on a previous dynamics model, the heat generation and thermal network models were integrated in the present study to predict the over-skidding and its thermal behavior. The model was validated in terms of the measured degree of over-skidding and temperature rise. The results showed that the degree of over-skidding reaches up to 12% of the theoretical value, and the friction power loss of the ball-pocket accounts for 30% of the total power loss. The analysis of the vibration signal showed a strong correlation between the bearing vibration characteristics and over-skidding behavior, thereby providing a way to indirectly measure the degree of over-skidding. [ABSTRACT FROM AUTHOR]

As the key component of a servo motor, the torque and temperature rise of the brake at the operating temperature affect the production quality of injection molding machines and other equipment. To achieve application of the brake and evaluate its performance at a high operating temperature, a high-torque permanent magnet brake with an axial disc structure is proposed. The permanent magnet consists of six small magnets instead of the traditional monolithic ring magnet. The key parameters of the coil are designed, and the magneto-thermal coupling method is established. The magneto-thermal coupling method considers the effect of temperature on material properties and feeds the temperature back to the electromagnetic field to correct the resistance, permeability, remanence and other coefficients. It then updates the heat source of the temperature field. The temperature rise is calculated iteratively between the electromagnetic field and the temperature field. The simulation results of the one-way method and the magneto-thermal coupling method are obtained and compared with the experimental results. The evaluation errors of the magneto-thermal coupling method for temperature and braking torque are 1.9% and 4.7% respectively, which are lower than the errors of the one-way method. [ABSTRACT FROM AUTHOR]

As the frozen soil in the South Pole region of the Moon is an important water resource, the operation of drilling and retrieving samples of the frozen soil in this region will be a crucial task for us to accomplish in future deep-space exploration. Thus, this paper investigated the effects of the increasing temperature and heat transfer between the drilling tools and the simulated lunar soil to minimize the degradation of the frozen soil samples during drilling due to the increased temperature. Specifically, the discrete element method was adopted and the heat transfer parameters of the discrete element particles were calibrated based on the equivalent heat transfer of the particle system. Moreover, a lunar soil particle system was developed for the simulations. Under the current working conditions with reasonable parameters, the maximum increase in the drill bit temperature was about 60 °C. Overall, the simulation results were consistent with the experimental results, and further analysis revealed that the flow of lunar soil can effectively take away thermal, which is also one of the reasons why the simulated lunar soil particles are in a high-temperature state at the front of the drilling tool. [ABSTRACT FROM AUTHOR]

The internal pressure and temperature of type IV on-board hydrogen storage cylinders constantly change during the hydrogen fast-filling process. In this work, a 2D axisymmetric computational fluid dynamics (CFD) model is established to study the temperature rise of hydrogen storage cylinders during the fast-filling process. The hydrogen filling rate, ambient temperature, volume, and hydrogen inlet temperature were investigated to evaluate their effects on temperature rise inside the cylinders. The effects of the inlet pressure rise and pre-cooling patterns on the temperature rise of large-volume type IV hydrogen storage cylinders are analyzed, and the optimal filling strategy is determined. The research results show that a greater filling rate causes a higher hydrogen temperature rise at the end. The ambient temperature increases linearly with the maximum hydrogen temperature and decreases linearly with the state of charge (SOC). As the volume increases, the temperature rise of the cylinder increases. Reducing the inlet hydrogen temperature helps control the temperature rise, and the hydrogen inlet pre-cooling temperature required for large-volume cylinders is lower. If the filling time remains unchanged, a high pressure rise rate should be avoided, and a linear pressure rise pattern is optimal. Reducing the initial cooling energy is key to optimizing the filling strategy. [ABSTRACT FROM AUTHOR]

The efficiency of solar cell and the corresponding output power is mainly affected by the rise in the film temperature, and in such cases, the stability in thermal conductivity value is required to ensure adequate rate of heat loss. This study investigates the effect of temperature rise on the overall thermal conductivity of the perovskite cell including the response of polymeric additives that have been used recently to enhance the interaction between different grains in perovskite films. The polymers under study are: polyethylene oxide (PEO), polyacetylene (PA), polythiophene (PT), polystyrene (PS) and polymethyl methacrylate (PMMA). The work assumes mathematical procedure that links the variation of temperature to the degree of polymer’s crystallinity and then converting this impact in terms of thermal conductivity. The calculations assumed three different concentrations of the polymer as: 1, 3 and 5%. Each polymer has served with two degrees of crystallinity. In general, the results show that the effect of added polymers on the final value of the thermal conductivity of the film may be positive or negative depending on three main factors: k-value of the perovskite-based material, k-value of the polymer and concentration of the polymer. The effect of the polymer appears more when it is used with the low k-value perovskite material (0.2 W/m∙K) rather than with high k-value perovskite material (0.8 W/m∙K). The addition of PEO to the perovskite-based materials makes the overall k-value of the film reaches to 3.7 W/m∙K and even higher when the temperature rises up. Hence, this polymer is useful in high operation temperature. In the case of using polymers (PA and PT), the overall k-value of the film was less sensitive. The use of amorphous polymers (PS and PMMA) has not witnessed any significant contribution in the overall k-value of the film. [ABSTRACT FROM AUTHOR]

The temperature effect caused by high slip has an important influence on the operation performance and reliability of magnetic coupling. Taking the self-developed single disk asynchronous magnetic coupling as the research object, the heat loss equation of the magnetic coupling is established. Based on the three-dimensional transient magnetic field simulation model of the magnetic coupling, the eddy current loss, torque, and eddy current distribution law of the magnetic coupling are obtained through simulation. The space flow field and structure temperature field distribution of the magnetic coupling are analyzed by using the fluid-thermal coupling simulation method, and the heat dissipation coefficient and temperature distribution law of the structure surfaces such as copper disk, the back lining yoke iron disk, and the aluminum disk are obtained. The test platform was built to test the torque and temperature of the magnetic coupling. The results show that the error between the test and simulation is 4.8% in the torque aspect, and the maximum error between the test and simulation is only 8.1% in the temperature aspect of each component, which further verifies the effectiveness of the simulation method. On this basis, three heat dissipation improvement schemes are proposed, including installing heat dissipation blocks, setting semicircular grooves on the back lining yoke iron disk, and a hybrid design. The results show that the degree of improvement for each scheme is in the following order: hybrid design, setting semicircular grooves on the back lining yoke iron disk, and installing heat dissipation blocks. Under the hybrid design, the temperature of the back lining yoke iron plate and a copper plate of the magnetic coupling is reduced by about 8.5 °C compared with the original model, and the effect is ideal. The research results can provide an optimization reference for high-speed magnetic coupling and the temperature effect caused by an overload-locked rotor. [ABSTRACT FROM AUTHOR]

This paper investigates the month-wise impact of COVID-19 conditions on residential load due to people's presence at home during office hours in Memphis city, Tennessee, USA. The energy consumption patterns of four consumers are analyzed based on the data available from pre-COVID to continuing COVID-19 situations. It is observed that the energy consumptions from April 2020 to June 2021 for all families have increased during office hours than that of pre-COVID months. Therefore, the impacts of the increased loads on distribution transformer are analyzed in terms of hottest spot, top-oil temperature, and loss of transformer life. Moreover, an experimental setup is made to produce the harmonics in currents of non-linear residential load which has detrimental effects on temperature rise of distribution transformer. In addition, this work proposes implementation of harmonic filter at the load side considering the impact of harmonics produced by loads to reduce the temperature rise due to the increased load consumption and presence of harmonics in currents produced by the load. The rise in temperatures and the loss of life of distribution transformer with and without the proposed solutions are simulated in MATLAB to show the efficacy of the proposed solution. Moreover, cost value analysis among different methods, which can be implemented to reduce the adverse impact on distribution transformer, are provided to rank the available methods. [ABSTRACT FROM AUTHOR]