Excessive Heat Research Articles

Assessing transformer health through analysis of dissolved gases in cooling oil

Gases can form within the insulation system for various reasons while a transformer is in operation. If these gases are not promptly and properly managed, they can negatively impact the transformer's performance. Using the dissolved gas analysis (DGA) method to identify and assess the type and quantity of dissolved gases in transformer oil can uncover potential issues within the transformer. This information is crucial for guiding preventive maintenance and necessary repairs. Dissolved gas analysis testing was conducted by extracting transformer oil samples to identify signs of disturbances in the transformer based on the dissolved gas content. This research was conducted at the Paiton plant operations and maintenance services division. The condition of transformers was assessed by analyzing dissolved gases using the Rogers ratio method. Results indicate that the transformer at Paiton 9 is in good condition but overheating has occurred and requires treatment. Conversely, the transformers at Paiton 1 and 2 are in poor condition, showing signs of electrical faults and excessive heat. Despite several attempts to add inhibitors and conduct frequent testing, the transformers remained in poor condition, necessitating their replacement or repair.

Development of ITER first wall heat load feedback control

Real-time monitoring and control of thermal loads on tungsten plasma-facing components is mandatory for ITER to avoid their overheating during plasma discharges. For the Start of Research Operations (SRO) phase, dedicated First Wall Heat Load Control (FWHLC) functions are included in the ITER Plasma Control System (PCS) to prevent the development of excessive plasma heat loads on the inertially cooled first wall (FW). In this work, we propose a FWHLC design with a model-based approach, which features a simplified thermal model for the FW armour. This control-oriented model simulates the thermal response of ITER FW to slow changes in plasma equilibrium and energy, which during ITER operation will be monitored by the real-time wide angle infrared camera system. This allows computationally efficient runs for rapid controller performance assessment but can also assist operation scenario design by pre-empting potential heat load issues. FWHLC is designed to react to measured and predicted FW temperatures overcoming predesigned limits with real-time variations of the plasma shape or auxiliary power references, aiming to reduce thermal loads before a premature plasma termination is required to protect the FW. The new scheme is tested in closed loop simulations, where perturbations to nominal ITER low current scenarios are introduced in the wall thermal model to trigger the response of FWHLC, supporting the effectiveness of the proposed policy.

Effect of post-weld heat treatment on microstructure and mechanical properties of induction roll welded joint for A283GRC steel and 5052 aluminum alloy

Steel-aluminum transition joints are commonly produced through explosive welding and friction welding techniques, serving to link aluminum pressure vessels with steel pipes within cold boxes in air separation unit. This study investigates the impact of PWHT on the microstructure and mechanical properties of steel-aluminum transition joints created via IRW, utilizing A283GRC steel and 5052 aluminum alloy as substrates. The findings suggest that the types of intermetallic compounds (IMCs) in IRW joints remain unchanged before and after heat treatment. The thickness of interfacial IMCs increases with higher annealing temperature and longer annealing time, with a faster growth rate at higher annealing temperatures. After PWHT, the grain size near the interface of the joint on the steel side decreased, with the most significant decrease observed when annealed at 300 °C for 2 hours. While cracks in the interface zone gradually diminish or disappear with PWHT, excessive heat treatment temperature or duration may result in new transverse cracks. At an annealing temperature of 200 °C, there is limited growth range for IMCs and noticeable repair effect on cracks within the interface region. When annealed at 300 °C and 400 °C, there is a decrease in joint hardness compared to before heat treatment levels, and this decreasing rate accelerates with higher annealing temperature and longer duration. Following annealing at 300 °C for 2 hours, the shear strength of the sample reached 70.52 MPa, which is 32% higher than that before heat treatment. Overall findings suggest that the annealing temperature exerts a more pronounced impact on the mechanical properties of joints in comparison to the annealing duration across the investigated time and temperature ranges. The fracture mode exhibited by the samples before and after heat treatment in IRW is characterized by a mixed fracture mode. However, the predominant fracture mode observed without heat treatment is brittle fracture, whereas after heat treatment, ductile fracture becomes the primary mode of fracture.

Analisis profitabilitas dalam isu perubahan iklim global pada CV. Kelapa Inti Murni

Climate change is a global issue that remains a significant topic of discussion among many countries, including Indonesia. This is clearly expected to impact companies in areas such as sales and company profits. To analyze the risks and opportunities related to climate change on the profits generated by a company, it is essential to measure using profitability ratios. Profitability measures a company’s ability to generate profit from a certain level of sales, assets, and equity capital. This study aims to analyze the profitability in the context of global climate change issues at CV. Kelapa Inti Murni. This research is qualitative with a descriptive approach. The types of data used are quantitative and qualitative. Data sources include primary and secondary data. Data collection methods used are observation, interviews, and document analysis. The data analysis method employs profitability ratios. The research findings indicate that profitability at CV. Kelapa Inti Murni is related to climate change. If there is a climate change event such as excessive heat, the company's profitability is expescted to decrease due to reduced sales or minimal profits. Overall, the company's profitability is considered quite good as it is above the industry average, except for return on equity which remains below the industry average standard.

Modeling and Monitoring of the Tool Temperature During Continuous and Interrupted Turning with Cutting Fluid

In metal cutting, a large amount of mechanical energy converts into heat, leading to a rapid temperature rise. Excessive heat accelerates tool wear, shortens tool life, and hinders chip breakage. Most existing thermal studies have focused on dry machining, with limited research on the effects of cutting fluids. This study addresses that gap by investigating the thermal behavior of cutting tools during continuous and interrupted turning with cutting fluid. Tool temperatures were first measured experimentally by embedding a thermocouple in a defined position within the tool. These experimental results were then combined with simulations to evaluate temperature changes, heat partition, and cooling efficiency under various cutting conditions. This work presents novel analytical and numerical models. Both models accurately predicted the temperature distribution, with the analytical model offering a computationally more efficient solution for industrial use. Experimental results showed that tool temperature increased with cutting speed, feed, and cutting depth, but the heat partition into the tool decreased. In continuous cutting, cooling efficiency was mainly influenced by feed rate and cutting depth, while cutting speed had minimal impact. Interrupted cutting improved cooling efficiency, as the absence of chips and workpieces during non-cutting phases allowed the cutting fluid to flow over the tool surface at higher speeds. The convective cooling coefficient was determined through inverse calibration. A comparative analysis of the analytical and numerical simulations revealed that the analytical model can underestimate the temperature distribution for complex tool structures, particularly non-orthogonal hexahedral geometries. However, the relative error remained consistent across different cutting conditions, with less error observed in interrupted cutting compared to continuous cutting. These findings highlight the potential of analytical models for optimizing thermal management in metal turning processes.

Mitigating excessive heat in Arabica coffee using nanosilicon and seaweed extract to enhance element homeostasis and photosynthetic recovery.

Global warming-related temperature increases have a substantial effect on plant and human health. The Arabica coffee plant is susceptible to growing in many places across the world where temperatures are rising. This study examines how nanosilicon and seaweed extracts can improve Arabica coffee plant resilience during heat stress treatment (49.0 ± 0.3°C) by maintaining mineral homeostasis and photosynthetic ability upon recovery. The principal component analysis arrangement of four treatments, nanosilicon (Si), seaweed extract (SWE), Si + SWE, and control (CT), showed each element ratio of magnesium, phosphorus, chloride, potassium, manganese, iron, copper, and zinc per silicon in ambient temperature and heat stress that found influenced upper shoot rather than basal shoot and root within 74.4% of largest feasible variance as first principal component. Magnesium and iron were clustered within the silicon group, with magnesium dominating and leading to a significant increase (p ≤ 0.05) in magnesium-to-silicon ratio in the upper shoot under heat conditions, especially in Si and Si + SWE treated plants (1.11 and 1.29 fold over SWE treated plant, respectively). The SWE and Si + SWE treated plants preserved chlorophyll content (15.01% and 28.67% over Si-treated plant, respectively) under heat stress, while the Si and Si + SWE treated plants restored photosynthetic efficiency (Fv/Fm) better than the SWE treated plant. The concomitant of the Si + SWE treatment synergistically protected photosynthetic pigments and Fv/Fm by adjusting the magnesium-silicon homeostasis perspective in Arabica coffee to protect real-world agricultural practices and coffee cultivation under climate change scenarios.

Barley vulnerability to climate change: perspectives for cultivation in South America.

Barley (Hordeum vulgare) is a globally significant cereal crop, widely used in both food production and brewing. However, it is particularly vulnerable to climate change, especially extreme temperature fluctuations, which can severely reduce yields. To address this challenge, a detailed climate zoning study was conducted to assess the suitability of barley production areas across South America, considering both current conditions and future climate scenarios from the Intergovernmental Panel on Climate Change (IPCC). The study utilized historical climate data along with projections from the CMIP6 IPSL-CM6A-LR model for the period 2021-2100. Several indices, such as evapotranspiration, were calculated, and factors like soil composition and topography were integrated into the classification of regions based on their agricultural potential. Critical variables in this assessment included temperature, precipitation, and water or thermal excess. The results showed that 6.59% of South America's territory is currently suitable for barley cultivation without additional irrigation, with these regions concentrated primarily in temperate southern areas. In contrast, 18.62% of the region is already unsuitable due to excessive heat. Projections under future climate scenarios indicate a shrinking of suitable areas, alongside an expansion of unsuitable regions. In the worst-case scenario, only 1.48% of the territory would remain viable for barley farming. These findings emphasize the crop's vulnerability to climate change, underscoring the urgency of developing agricultural adaptation strategies. The predicted contraction in suitable barley cultivation areas demonstrates the profound impact of climate change on agriculture and highlights the need for proactive measures to ensure sustainable barley production in South America.

Failure Analysis of Burst Tube Caused by Corrosion Thinning of the Tube Wall of Boiler Economizer

Abstract A boiler economizer is in continuous operation during several burst pipes. Burst tubes are located near the elbow below the weld, and the weld on both sides of the tube wall is thinning seriously. There is a flue gas formation vortex in the furnace chamber; the outer wall of the tubes is thicker ash, and fins and tubes are corroded to varying degrees. This study employed meticulous macroscopic observation, precise chemical composition analysis, detailed metallography, advanced scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) to determine the causes of the coal economizer tube burst and tube wall thinning, ensuring the accuracy of the findings. The chemical composition, microstructure, and grain size of the base material met the requirements of the relevant standards. The heat-affected zone and weld seam show the Widmannstatten structure, a superheated tissue caused by excessive heat input during welding. The outer wall of the pipe corrosion is more serious, resulting in serious wall thinning, and ultimately, the pipe bursts, unable to withstand the pressure inside the pipe. It was eventually determined that the cause of the pipe burst was that the operating temperature of the economizer was close to the dew point, and the flue gas contained sulfur dioxide, sulfur trioxide, and hydrogen chloride that met water vapor at that temperature to form acid. Acid on the outer wall of the pipe was caused by flue gas dew point corrosion, seriously causing the pipe wall to thin. When the pipe wall is thinned to a certain extent due to corrosion, it cannot withstand the pressure inside the pipe, and rupture will occur.

Feasibility of using toroidal transceivers for acquiring intraoperative MR images around deep brain stimulation electrodes

IntroductionMagnetic resonance imaging (MRI) provides excellent soft tissue contrast for visualizing of deep brain stimulation (DBS) targets, allowing validation of the electrode placement, and assessing complications such as microhemorrhage and edema. However, the presence of the electrodes can introduce challenges such as radiofrequency (RF) induced current artifacts and excessive heating of the electrode contacts. Additionally, extended procedure times are also considered a disadvantage when using MRI as an intraoperative imaging modality following DBS electrode placement. MethodWe propose a novel approach of using toroidal resonators to inductively couple the shaft of the electrode to the scanner's transmit-receive chain thereby utilizing it as a localized imaging antenna. The small extent of the field generated by the electrode antenna allows fast imaging with smaller field-of-views (FOVs) spanning only a few centimeters. Furthermore, we present a fast and accurate safety monitoring strategy that can be used to predict the temperature increase at the electrical contacts of the electrode. Results and DiscussionImaging with the toroidal transceiver yields a higher signal-to-noise ratio (SNR) efficiency in proximity to the electrodes. This approach reduced the RF induced current artifacts around the electrode which enhanced the visibility of the shaft and improved electrode localization. Moreover, the limited sensitivity around the electrode can be exploited to perform fast scans with small FOVs. The predicted heating around DBS contacts was in quantitative agreement with the experimental heating in swine studies with a normalized root-mean-square error (NRMSE) ≤ 0.09.

Brain temperature, brain metabolites, and immune system phenotypes in temporal lobe epilepsy.

Epileptogenesis is linked to neuroinflammation. We hypothesized that local heat production caused by neuroinflammation can be visualized non-invasively invivo via brain magnetic resonance spectroscopic imaging (MRSI) and MRSI-thermometry (MRSI-t) and that there is a relationship in patients with temporal lobe epilepsy (TLE) between MRSI-t and brain metabolites choline and myo-inositol and between neuroimaging and cellular and serum biomarkers of inflammation. Thirty-six (36) participants, 18 with temporal lobe epilepsy (13 females) and 18 age-matched healthy controls (nine females), were enrolled prospectively and underwent MRSI/MRSI-t; TLE participants also provided blood samples. Temperature was measured using creatine as a reference metabolite. Analysis of Functional NeuroImages 3dttest++ tool was used to analyze voxel-level group differences in temperature, choline, and myo-inositol. Associations with immune cell subsets, cytokines, and chemokines related to inflammation were quantified using correlation coefficients with significant relationships as noted. Patients with TLE showed elevated temperature, choline, and myo-inositol in the temporal lobes. Higher brain temperature was associated with higher levels of cytokines and chemokines, including GM-CSF, TNF, IL-1β, and IL - 12p70, and lower frequency of immune cells including CD3+ T-cells, CD4+ T-cells, CD8+ T-cells, and classical monocytes. Higher choline was associated with higher levels of the cytokines including LT-α, IL-13, and IL-4, and higher myo-inositol was associated with a higher frequency of CD4+ T-cell and CD19+ B-cell subsets and higher levels of cytokines and chemokines including LT-α, IL-13, and CCL3. This study, for the first time, showed that in temporal lobes of patients with TLE temperature and metabolite changes correlate with cellular and serum biomarkers of inflammation. Our results provide support for further development of MRSI-t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool. Neuroinflammation is associated with excessive heat production which can be visualized with magnetic resonance spectroscopic imaging and thermometry (MRSI-t). We prospectively investigated the relationship between MRSI-t and cellular and serum measures of peripheral inflammation in patients with temporal lobe epilepsy (TLE); we compared the results of MRSI-t in patients with TLE to healthy controls. We showed a relationship between the temperature elevations in TLE and elevations of various measures of peripheral inflammation. Our results support further development of MRSI-t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool.

Thermal explosion and distribution of hydromagnetic Eyring–Prandtl double exothermic diffusion-reaction fluid in a porous channel

Harmful waste discharge poses a global threat to environmental degradation, as incomplete combustion of hydrocarbons can lead to unusual diseases and natural disasters, as well as toxic discharge. Therefore, this research aims to investigate the thermal explosion and distribution of hydromagnetic Eyring–Prandtl fluid during double exothermic combustion in a porous channel. The working Eyring–Prandtl fluid is assumed to be fully viscoelastic to inspire the combustion process in the absence of material deformation. A partial differential model of an electromagnetic pressure-driven flow is developed to govern the combustion reaction process in the presence of chemical kinetics, non-isothermal fixed wall constraints, and without fluid material reactant consumption. The model is transformed into an invariant form by introducing similarity variables; the resultant dynamical equations are solved via a finite difference semi-implicit scheme. The graphs and tables demonstrate that the rising parameter values for the double reaction step propelled heat transfer to help improve combustion processes. Also, the material dilatant parameter enhanced the fluid viscosity for increased chemical industrial usage which implies that, excessive heat generation due to exothermic combustion must be supervised to circumvent reactant species blowup. In addition, the magnetic field created complex dynamics in the fluid by introducing electromagnetic Lorentz forces, which changed the reaction rate and heat distribution inside the channel. Furthermore, there is a strong positive correlation between the results obtained in the current study and the existing published data.

Steady and periodical heat-mass transfer behavior of mixed convection nanofluid with reduced gravity, radiation and activation energy effects

Significance of this study is to explore Arrhenius activation energy, microgravity, chemical reaction and porous medium effects on Darcy nanofluid over a stretching sheet with nonlinear thermal radiations. Purpose of this study is to enhance the lubrication efficiency, excessive heat reduction, surface roughness and tool wear in drilling, milling, grinding and cutting tools of machining procedures. Use of Brownian and thermophoretic nanoparticles in base liquid is very effective to reduce friction in tool-chip and tool-work interfaces, tool life ability and cooling ability through nanofluid minimum quantity lubrication in machining operations. A refined mathematical model is solved using dimensionless variables; oscillatory stokes conditions and primitive variables. The implicit form of finite difference method is applied for numerical results using Gaussian elimination approach. The numerical and physical outputs are secured using Gaussian elimination methodology in FORTRAN tool and TecPlot-360. Graphs are displayed by using numerical data in Tecplot-360 program. Impact of activation energy (AE), solar radiation (Rd), microgravity (RG), porosity (Ω), thermophoresis (NT), chemical reaction (Kr), Prandtl (Pr) and Schmidt factor (Sc) on oscillating frequency of heat and mass transport is depicted. Amplitude in fluid velocity, surface temperature and volume of concentration is enhanced as radiation, microgravity and activation energy increases. It is noted that the increasing amplitude in fluid velocity, temperature and fluid concentration is found with activation energy, radiation and buoyancy force effects. Steady behavior of skin friction and mass transport decreases as Darcy porous medium and reaction rate decreases. Frequency of oscillating skin friction and oscillating heat transfer increases as Schmidt and Prandtl coefficient increases. Fluctuations and amplitude in the frequency of heat and mass transport enhances as thermophoretic nanoparticle enhances.

Extreme Heat and Specific-Cause Mortality during Summer 2018 in Mainland Portugal

Abstract Climate change has led to increased frequency and duration of extreme heat periods, impacting human health and mortality. During the 2003 heatwave, it was estimated that there were between 25,000 and 70,000 excess deaths in Western Europe. Specific-cause mortality analysis was conducted in Portugal that year and has not been assessed since. The goal of this study is to estimate the impact of an extreme heat period in 2018 on specific-cause mortality in mainland Portugal. An ecological study was conducted comparing observed and expected deaths, from August 2 to 9, 2018, in Portugal. Two comparison periods were chosen: from July 19 to 26, 2018 (C1) and the average deaths from August 2 to 9 in 2017 and 2019 (C2). Excesses, ratios, and respective 95% confidence intervals were calculated in R. Analyses were stratified by sex, age group, and district. Consistent excess deaths were observed between comparators, showing a greater impact in circulatory diseases (C1: 283, 95% CI: 210; 356 and C2: 239, 95% CI: 164; 314) and respiratory diseases (C1: 98, 95% CI: 55; 141 and C2: 95, 95% CI: 52; 138). Regarding death ratios, with C1, the highest death ratios were observed for exposure to excessive natural heat (50.00, 95% CI: 37.11; 65.92) and ischemic stroke (4.00, 95% CI: 2.07; 6.99). With C2, the highest death ratios were observed for exposure to excessive natural heat (50.00, 95% CI 37.11; 65.92) and atherosclerosis (2.71, 95% CI 1.63; 4.24). The excesses and ratios of deaths were higher in more urbanized districts, females, and age groups above 75 years. The results suggest that the extreme heat in 2018 had an impact on mortality. Elevated death ratios and excesses were observed for various causes of death with considerable statistical magnitude and significance. These findings align with other national and international studies. Public health action is increasingly critical to mitigate the observed rise in mortality during periods of extreme heat. Key messages • Specific-cause mortality analysis during extreme heat suggests a greater impact in circulatory and respiratory diseases, in residents of urbanized districts, females, and individuals of 75+ years. • Understanding these specific causes can better inform public health actions and planning, thereby mitigating the adverse effects of extreme heat.

Climate change and its health effects - an optional subject for medical students

Abstract The Standing Committee of European Doctors urged to include training on the impact of climate change on health for health professionals. Currently, in the curriculum of most medical schools, the health-related impacts of climate change represent a peripheral part. The teaching of health effects of climate change should be made part of the training of health professionals and should be introduced in the curriculum of medical schools. ClimateMed is an Erasmus project that improves the curriculum and expands knowledge about the health effects of climate change at medical universities. The World Café method, based on round table discussions, was applied to assess the needs, summarize the proposals, and develop the necessary strategy. At the same time, a questionnaire was applied to those medical students from UMFST Targu Mureș who chose this subject as an optional subject. Students related the importance of understanding the diseases caused directly or indirectly by climate change, and reported what kind of topics should be included in a new course, in which semester/module and in what format it would be appropriate to teach it. The most frequently reported topics were: excessive heat and heat-related illnesses, extreme weather, vector-borne diseases, food safety, air pollution, and mental health. According to the goals of the project and students’ opinions, since 2023 medical students can choose Climate Change and Health Effects as an elective course. Based on the demand for medical universities to include in their curriculum knowledge related to the health effects of climate change, ClimateMed project can facilitate this integration and can promote the increase of teacher motivation and the development of methodological guidelines for university teachers. The project contributes to the preparation of some educational materials and the introduction of an optional subject in the training curriculum of the students of the Faculty of Medicine, UMFST Targu Mureș. Key messages • There must be made efforts to include training on the impact of climate change on health for health professionals, to introduce this subject in the curriculum of medical schools. • ClimateMed project can facilitate the integration of knowledge about the health effects of climate change into curriculum and can promote the practical use.

Next-generation public health surveillance: extreme heat event prediction and monitoring system

Abstract Background Extreme Heat Events (EHEs) are a growing threat to public health. The increase in the frequency of occurrence of once rarer EHEs and the rise in their average temperatures are dangerously drastic for public health outcomes. Despite this, existing public health surveillance (PHS) systems fail to leverage IoT and AI technologies to facilitate real-time, continuous monitoring of EHE indicators and its associated health risks. This study closes this gap by proposing a comprehensive PHS system that can, in real-time monitor and predict EHE indicators to provide timely alerts to public health authorities. Methods The EHE PHS system collects EHE detection metrics, including indoor temperature and humidity levels, from IoT sensors and thermostats to map them across Canada, primarily focusing on low-income communities. The system also integrates historical climate data (surface temperature, humidity, wind speed and direction, and air quality indicators) from Environment Canada. The system uses the data to train initial prediction models including CNN, LSTM and GNN. The validated model will be integrated into the system, enabling real-time EHE prediction. The output will be displayed in user-friendly visualizations on the EHE PHS system’s dashboard capabilities. Results The system allows for the analysis of real-time data through dashboards and provides alerts when certain indicators (e.g. excessive or prolonged heat) detrimental to public health outcomes are detected. The alerts enable valuable lead time for public health authorities to implement proactive measures, such as issuing heat advisories and deploying resources to vulnerable areas. Conclusions The EHE PHS system will serve as a blueprint for global public health researchers, utilizing IoT and AI technologies for proactive crisis prevention. This knowledge will inform the development of heat-resilient policies and set a precedent for global public health crisis prevention. Key messages • The proposed EHE PHS system uses AI and IoT technologies, to enhance EHE prediction, risk identification, and real-time monitoring for effective public health interventions. • By integrating advanced predictive models and environmental data, the system facilitates early detection of EHE risk, which can significantly mitigate the health impact on vulnerable populations.

Asymmetric Aramid Aerogel Composite with Durable and Covert Thermal Management via Janus Heat Transfer Structure.

Warmth preservation in cold climates requires a long-term heat supply. Conventional thermal devices usually deliver excessive heat and have difficulty preventing heat loss. Herein, to achieve durable thermal comfort, an asymmetric composite (AAAC) is devised through vacuum-filtrating silver nanowires (AgNWs) onto the surface of a poly(ethylene glycol) (PEG)-infiltrated aramid nanofiber aerogel. AgNW e-skin can transfer strong Joule heat to the back side of the AAAC, where the infused PEG further stores thermal energy by phase transition and then releases it to the body constantly after the power is off. Base on the Janus structure, the AAAC can provide thermotherapy for human waists and knees, holding a suitable temperature range of 37-39 °C for 5-8 min without a heat source. In addition, low infrared emissivity (0.064-0.315) of e-skin allows the AAAC to conceal thermal targets while producing Joule heat, which achieves comfortable and safe thermal management in multiple occasions including daily life and military warfare.

Trend and teleconnection analysis of temperature extremes in New South Wales, Australia

AbstractThis study investigates possible trends and teleconnections in temperature extremes in New South Wales (NSW), Australia. Daily maximum and minimum temperature data covering the period 1971–2021 at 26 stations located in NSW were used. Three indices, which focus on daily maximum temperature, daily minimum temperature, and average daily temperature in terms of Excessive Heat Factor (EHF) were investigated to identify the occurrence of heatwaves (HWs). The study considered HWs of different durations (1-, 5-, and 10-days) in relation to intensity, frequency, duration, and their first occurrence parameters. Finally, the influences of three global climate drivers, namely – the El Niño/Southern Oscillation (ENSO), the Southern Annular Mode (SAM), and the Indian Ocean Dipole (IOD) were investigated with associated heatwave attributes for extended Austral summers. In this study, an increasing trend in both hot days and nights was observed for most of the selected stations within the study area. The increase was more pronounced for the last decade (2011–2021) of the investigated time period. The number, duration and frequency of the heatwaves increased over time considering the EHF criterion, whereas no particular trend was detected in cases of TX90 and TN90. It was also evident that the first occurrence of all the HWs shifted towards the onset of the extended summer while considering the EHF criterion of HWs. The correlations between heatwave attributes and climate drivers depicted that heatwave over NSW was positively influenced by both the IOD and ENSO and negatively correlated with SAM. The findings of this study will be useful in formulating strategies for managing the impacts of extreme temperature events such as bushfires, floods, droughts to the most at-risk regions within NSW.

Improvement of curing efficiency and heat resistance of CFRP by the growth of SiCNWs on CF

Carbon fiber-reinforced polymer composites are widely used in modern industry. However, poor heat transfer between layers of carbon fiber cloth during the curing process leading to poor curing of the substrate, long curing cycles, and excessive heat accumulation has become an urgent problem to be solved. A common approach is dispersing highly thermally conductive fillers in the polymer matrix to improve the curing efficiency of the composites. Different from adding fillers, we report a novel method of in situ growth of SiC nanowires (SiCNWs) on the surface of carbon fiber (CF) by the chemical vapor deposition (CVD) method and study the effects of CVD deposition time on curing efficiency and thermal stability of the composites. The results indicate that the nano bridge effect of SiCNWs significantly improves the curing efficiency of the composites. Compared with pure CF/epoxy composites, the curing efficiency can be increased by 38.72%. The cross-linking point between SiCNWs and the resin matrix enhances the thermal stability of the composites and increases the heat resistance index ( T HRI) by 8.4°C.

THE STUDY OF THE TECHNICAL CONDITION OF GONDOLA CARS

The article presents the results of the analysis of the technical condition of gondola cars owned by the transport operator BGS rail. The composition of the model range of the car fleet was analysed. It is shown that 14 % of gondola cars produced by Uralvagonzavod have an average service life of over thirty years and have exhausted their service life. Gondola cars of models 12-757 and 12-753 of Kryukov Carriage Works have also exhausted their service life. A positive factor is the presence of innovative cars model 12-7023 produced by KVSZ and 12-4106 model produced by PJSC Dneprovagonmash in the car fleet. Their average age is 6.5 years.An analysis of the main causes of failures that caused the car to uncouple from the train along the route was carried out. In the first place are damage to body elements. This is followed by failures of automatic brakes and wheel sets.Among the damage to gondola car bodies, the first place is taken by malfunctions of the locks on the unloading hatch covers, followed by cracks and breaks in the upper and vertical sheets of the frame cross beams. Broken weld seams of braces and broken linings also pose a serious danger.Failures of auto brakes are caused by loosening of air duct pipes, brake equipment and welded shoes. The main causes of damage to wheel pairs are unacceptable wear of the flange. Among axle box assemblies, the vast majority of failures are caused by excessive heating of the bearings.Failures of automatic coupling equipment are most often caused by fractures of the centering beam and breaks (cracks) of the pendulum suspension. Cracks and other malfunctions of the automatic coupling body are also observed.The bogies mostly have broken springs and mismatched sliding clearances. Also, a quarter of the uncoupled bogies have expired service life of their elements. The average recovery time for gondola cars was analyzed. Due to malfunctions of axlebox units, cars are under repair for more than 15 days, due to failures of wheel pairs - 11.55 days. The least time is spent on auto brakes – 4.2 days.An analysis of the damage to the bodies of various gondola cars models showed that gondola cars of models 12-9745 and 12-9790 are in the worst technical condition. The least susceptible to damage are the «innovative» gondola cars of models 12-7023 and 12-4106.

Effect of dual NEPCM and tapered fins on thermal runaway control in lithium-ion batteries

This research investigates the thermal performance of dual phase change materials (PCMs) RT82 (PCM1) and RT27 (PCM2) using tapered fins and nanoparticles to improve their thermal management capabilities, specifically for controlling excessive heating in lithium-ion battery cells. The primary objective is to enhance heat transfer efficiency and melting characteristics of dual PCMs by incorporating alumina (Al2O3), molybdenum disulfide (MoS2), and single-walled carbon nanotubes (SWCNTs) nanoparticles at varying volume fractions and configuring tapered fins in different arrangements. A series of parametric studies were conducted to analyze the impact of these modifications on the thermal transport and solid-liquid transition characteristics of the PCMs. The key findings indicate that the incorporation of nano-sized particles significantly enhances the thermal conductivity of PCMs, with SWCNTs showing the highest improvement. The PCM system with 6 % SWCNTs nanoparticles exhibited a 41.85 % increase in melting characteristics compared to the baseline PCM. The study also reveals that increasing the number of fins from two to eight results in a 94.28 % increase in the melting rate for RT82 and a 50 % increase for RT27. Furthermore, the combination of increased nanoparticle concentration and fin number leads to a 12.17 % rise in melt pool temperature distribution for 2 % SWCNTs and 14.08 % for 6 % SWCNTs. The enhanced thermal conductivity and efficient heat transfer due to the synergistic effect of fins and nanoparticles result in faster phase transitions and improved temperature regulation within the system. These findings underscore the potential of optimized PCM configurations with advanced materials for superior thermal management solutions in high-heat applications, effectively extending the operational efficiency and lifespan of thermal systems like lithium-ion batteries.