Hot Environment Research Articles

Potential health risks of inhaling hazardous chemical exposures at fuel stations: a pilot study in a hot, arid environment

In recent years, there has been a growing focus on the issue of exposure to hazardous chemical compounds and the potential health risks associated with them. Fuel stations play a critical role in society, supporting the transportation industry and serving the general public. However, the routine activities at these stations expose workers and customers to dangerous chemical compounds, posing potential health risks. As part of a pilot study, the exposure of workers and customers to hazardous chemical compounds at fuel stations in Kuwait, characterized by its hot and arid environment, was investigated. The study specifically looked at volatile organic compounds (VOC) concentration and their effects on human health. Three hundred-eight air samples were collected in a hot, arid environment, focusing on fuel stations. Two sampling methods were used in this pilot study: personal inhalation exposure using active sampling and workplace air sampling using passive sampling. Samples were collected in fuel filling areas, indoor control rooms, and through personal exposures, adhering to ISO procedures (EPA TO-17). The study also assessed the non-carcinogenic and carcinogenic risks to human health to potential exposure to hazardous hazardous chemicals. The findings revealed that hazardous chemicals levels in the pump area were lower than those in the indoor control rooms. Workers’ inhalation exposure to hazardous chemicals remained below the international occupational exposure limit (OEL). However, the study identified unsafe inhalation exposure levels to Benzene, which could have adverse carcinogenic effects. In contrast, exposure to ethylbenzene was found to be within safe limits, with no associated carcinogenic effects. This study underscores the importance of identifying the risks associated with exposure to hazardous chemical compounds to minimize human health risks and promote a safe working environment.

Industrial workwear for hot workplace environments by coating with metal–organic framework NH2-MIL-125 (Ti): synthesis, characterization, coating, thermal conductivity coefficient and air permeability

Industrial workwear for hot workplace environments by coating with metal–organic framework NH2-MIL-125 (Ti): synthesis, characterization, coating, thermal conductivity coefficient and air permeability

Examination of the Effects of Wearing Surgical Masks during Emergency Operations in a Hot Environment on the Body of Paramedics

Examination of the Effects of Wearing Surgical Masks during Emergency Operations in a Hot Environment on the Body of Paramedics

Storage Properties of DPNR under Various Conditions

Maintaining the properties of deproteinised natural rubber (DPNR) after the production is critical and essential since it tends to deteriorate after the removal of proteins. During the preparation, transportation and storage, rubber may be exposed to contamination and an unfavourable environment that may affect the properties over time. Therefore, this work was conducted to determine the factors that affect the properties of DPNR during storage. In this work, DPNR samples were prepared with and without the presence of zinc oxide (ZnO) and hydrogen peroxide (H2O2) as contaminants. These samples were then stored under different environments such as opened room temperature (RT), closed RT, chilled and heated. Their physical properties were examined during 76 weeks of storage. NR control sample showed the most stable properties along the storage period studied. Removal of proteins in DPNR samples in overall has reduced its whole properties especially when it was contaminated with H2O2. These properties became worsen when the sample was stored in a hot environment (40 °C). Its properties such as Mooney viscosity and plasticity retention index (PRI) decreased significantly with time and reached below 70 MU and 40 units, respectively. This result was supported by the reduction of their molecular weight, which indicates the degradation of these samples during storage. The results showed that the quality of DPNR could be compromised by the presence of contaminants such as H2O2 during production and would be worsen by improper storage conditions.

Determination of the optimal dose and dosing strategy for effective L-menthol oral rinsing during exercise in hot environments.

This multi-study programme investigated the optimal concentration of L-menthol delivered as an oral mouth rinse to modulate thermo-behaviour during exercise in a hot environment (35°C). In study 1, 38 participants completed a survey to establish an effective and tolerable range of L-menthol concentration. 31 participants completed an RPE-protocol examining 1. the dose-response effect of L-menthol mouth rinse on exercise performance (n = 16) and 2. the temporal effectiveness of administering L-menthol in an incremental and decremental dosing pattern (n = 15). Power output, heart rate, body core temperature and thermal sensation were reported throughout. The optimal menthol concentration for peak power was between 0.01 and 0.1% (~ 6% increase, P < 0.05) and 0.5% (~ 9% increase, P < 0.05) with respect to control. Work completed was increased at 0.01% (~ 5%, P < 0.05), at 0.1% (~ 3%, P < 0.05) and had a detrimental effect at 0.5% (- 10% decrease, P < 0.05). There were no differences between an ascending dose protocol (0.01 to 0.5%), descending dose protocol (0.5-0.01%) or a constant 0.01% dose protocol. There were no reported differences in body core temperature or heart rate across trials (P > 0.05). The optimal dose of L-menthol when delivered via oral rinsing is between 0.01 and 0.1%. At lower concentrations, L-menthol appears to be less effective and at higher concentrations (> 0.5%) L-menthol appears to elicit greater irritation and may not positively modulate thermo-behaviour during exercise in a hot environment.

A modified multi-node human thermoregulation model with improved sweating response to simulate human physiological behaviours in warm and hot environments

The present research developed a modified multi-node thermoregulation model derived from the renowned Tanabe and JOS series models (JOS-2 and JOS-3). The JOS-3 model's predictions showed an abrupt spike in mean skin temperature, contradicting the findings from experiments. The JOS-3 model's sweating mechanism exhibits an inconsistency, and the sweating mechanism is not triggered promptly and accurately, leading to a sudden rise in skin temperature. This disparity significantly impacts the ability of the model to precisely replicate thermoregulatory responses under various climatic conditions and levels of physical activity. The proposed modified thermoregulation model extends the JOS-3 model by modifying the set-point temperature and sweating signals. The performance of the developed modified thermoregulation model is thoroughly analyzed under various conditions involving different environmental conditions, activity levels, and clothing types. The proposed model eliminates abrupt rise in the mean skin temperature and improves its prediction accuracy, notably reducing mean skin temperature RMSE in hot-humid conditions (0.66 °C vs. 0.85 °C) compared to the JOS-3 model. In hot-dry settings, improvements are significant, reducing the mean skin temperature and core temperature RMSE (0.48 °C vs. 0.06 °C and 0.05 °C vs. 0.02 °C, respectively). Overall, the modified thermoregulation model offers a reliable and accurate solution to analyze human physiological conditions for a wide range of practical problems.

Poultry Preslaughter Operations in Hot Environments: The Present Knowledge and the Next Steps Forward.

Poultry production faces significant challenges, including high feed prices, diseases, and thermal stress, which impact broiler welfare and productivity. Despite advances in cooling technologies and ventilation, preslaughter operations still lead to considerable losses. This review highlights the need for the improved management of thermal environments and animal logistics. Preslaughter operations typically involve fasting broilers for 8-12 h to reduce gastrointestinal contents and contamination. Following fasting, broilers are caught, crated, and transported. Stress levels vary based on distance and conditions, with manual catching often causing stress and injuries. Catching should occur during cooler periods to minimise these issues, and transport conditions must be carefully managed. Lairage, the waiting period after transport, should be kept short (1-2 h) in climate-controlled environments to avoid stress and deterioration. Proper handling and efficient unloading are essential to prevent injuries and reduce economic losses. Stunning methods, such as electronarcosis and a controlled atmosphere, aim to minimise suffering before slaughter, though practices vary culturally and religiously. Logistics and real-time monitoring technology are crucial for enhancing animal welfare during transportation. Effective planning and the optimisation of transport processes is vital for reducing stress and losses, especially with regard to rising global temperatures and production demands.

Preferences for drinking water temperature in mice vary with ambient temperature.

Temperature detection and temperature preference are critical for the maintenance of thermal homeostasis and protection from noxious temperature. Methods to measure the time spent on plates of different temperatures such as the two-plate test and thermal-gradient test are generally used to evaluate temperature preference. In this study, we established a temperature preference test that assesses water drinking behavior by modifying the two-bottle taste preference test. We found that mice in a common-temperature environment of 23 °C avoid drinking water more than 40 °C. While mice in a common-temperature environment preferred 10 °C and 30 °C water equally, mice in a hot environment at 35 °C preferred to 10 °C water compared to 30 °C water. Moreover, mice in a cold environment of 10 °C did not avoid drinking 40 °C water compared to 10 °C water. From these results, the temperature preference test that we developed could be used to evaluate temperature preference owing to the ambient temperature changes.

Time-varying moisture characteristics and C-S-H gel properties of concrete in dry and hot environments

The construction of deeply buried tunnels has intensified concerns regarding shrinkage cracking and the long-term performance deterioration of lining concrete in dry-hot environments. These issues are related to the dynamic interconversion of internal moisture states, the changing moisture behavior over time, and the evolution of calcium silicate hydrate (C-S-H) properties. However, the mechanisms underlying these phenomena are not fully understood. This study investigates the dynamics of moisture content across different states, the source and composition of evaporated water, as well as the mechanism of change in the microscopic properties of C-S-H in concrete subjected to dry-hot conditions (40℃ and 60℃) and standard curing environments through tests on water loss rates, chemically bound water, and low-field nuclear magnetic resonance. The findings reveal that at 40℃ and 60℃, hydration products were generated rapidly before mold removal, leading to significant increases in chemically bound water, interlayer water, and gel water, while capillary water was notably consumed. After mold removal, the rate of chemically bound water increase slowed, while interlayer water, gel water, and capillary water evaporated significantly, with gel water comprising 87.27 % and 83.51 % of the evaporated water at 40℃ and 60℃, respectively. From day 1 to day 28, interlayer water, gel water, and capillary water contents decreased significantly, with reductions of up to 85.98 % at 60℃. In dry-hot environments, moisture primarily exists as chemically bound water and gel water, contrasting with standard curing conditions where capillary water is also present. The study concludes that drying of C-S-H gels leads to both positive effects, such as interlayer space compression and increased indentation modulus, and negative effects, including increased microporosity and reduced matric densification, ultimately contributing to the deterioration of long-term mechanical properties.

A novel ZnO-TiO2-Bi2WO6/Carboxymethyl chitosan composite with high antimicrobial activity and visible-light catalytic degradation of ethylene towards banana preservation in hot and humid environments

In order to solve the problem of significantly shortened storage time of bananas in hot and humid environment (e.g., 30 °C and 90 % relative humidity), this paper reports the preparation of ZnO-TiO2-Bi2WO6 (ZTB) ternary heterojunction antimicrobial photocatalysts composite carboxymethyl chitosan film (ZTB/CMCS). ZTB were prepared by hydrothermal method and composited with CMCS by surface deposition method to construct ZTB/CMCS edible nano-preservation film. It is noteworthy that the ZTB/CMCS composite film exhibited excellent antibacterial efficiency (>99.99 %) against E. coli and S. aureus suspensions (106 CFU/mL) after 24 h of incubation at 37 °C. Time-resolved photoluminescence (TRPL) spectroscopy showed that the incorporation of Zinc oxide nanoparticles (ZnO NPs) into the ZTB structure led to a decrease in fluorescence lifetime. Moreover, the interfacial interaction between ZnO and TiO2/Bi2WO6 inhibited the recombination of photogenerated electron-hole pairs, promoting carrier separation and improving photocatalytic activity. The combination of high antibacterial activity, photocatalytic degradation of ethylene and inhibition of gas exchange provided multiple protections for fruit preservation. Therefore, this work provides a novel, effective and safe method for prolonging the preservation of bananas in hot and humid environments.

Ibuprofen's Effect On Thermoregulatory Responses And Gastrointestinal Distress During Exercise In A Hot Environment

Ibuprofen's Effect On Thermoregulatory Responses And Gastrointestinal Distress During Exercise In A Hot Environment

Humidity Increases Carbohydrate Oxidation In Females During Walking Under Load Carriage In A Hot Environment

Humidity Increases Carbohydrate Oxidation In Females During Walking Under Load Carriage In A Hot Environment

Physiological and perceptual responses of firefighters wearing protective clothing under various training environment and activity conditions

To enhance operational capabilities of firefighters in live-fire scenarios, daily training is absolutely important which involves various types of training tasks in diverse thermal environments. Fire training in heat may impose severe heat stress on firefighters. Yet, the thermal burden associating with different training has rarely been studied. In this study, twelve healthy male firefighters performed 50 min of treadmill exercise while wearing firefighting protective clothing (FPC) in two environmental conditions (34°C and 37°C) with three training intensities (3 km/h, 4.5 km/h and 6 km/h). Results showed that in hot environments, training intensity exhibited a more pronounced effect on physiological responses than ambient temperature. Exposure to 37°C with heavy activity produced high level of core temperature (38.8±0.2°C), near maximal heart rate (164±18 bpm), increased energy expenditure (27.10±1.42 ml/min/kg) coupled with mild dehydration (2.08%±0.35%). The forehead, back and chest which showed the highest level of thermal sensation vote, wetness sensation vote and thermal comfort vote are suggested to be primarily considered when designing cooling strategies. Moreover, when providing recovery and cooling for firefighters working in extreme heat while wearing fully encapsulated FPC, the priority should be given to work intensity and duration, followed by environmental conditions.

Design of nature-inspired patterns on knitted fabrics for directional transportation of sweat and study of their performances

The human body in a hot environment or during intense training will sweat a lot. Traditional cotton fabrics are soft and breathable, but they tend to absorb moisture easily and evaporate it slowly, which makes people feel cold and wet. Sweat staying on fabrics for a long time could also cause bacteria to grow. Thus, it is necessary to transport the excessive sweat from the gathering section to the collection points along the surface paths in time to minimize such problems. The mechanism of directional water transport of desert beetles, cacti, nepenthes, and river meanders was referenced in this paper. The paths in dot, tree, V-shape, and river meander patterns were designed and manufactured from the inspiration of these natural architectures. The paths were coated on the surfaces of selected knitted fabrics with different structures through a one-step coating process. The optimal recipe of hydrophobic solution was determined when 0.1 g hydroxyethyl-cellulose (HEC) was added into MS-S002 solution. The results showed that sweat movement is mainly influenced by FL, FWD, FG, and knitted structure. The continuous and enclosed paths such as tree and river contribute to a better sweat moving track than those of dot and V-shape ones. Terry structure is more suitable for surface sweat transport than plain and pique. The highest movement speed of the terry structure with a tree pattern reaches 0.43 cm/s, followed by that of the terry structure with river pattern 0.35 cm/s. The coated fabrics also have ideal moisture and air permeability for wearing.

Impacts of age, type 2 diabetes, and hypertension on circulating neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 after prolonged work in the heat in men.

Prolonged work in the heat increases the risk of acute kidney injury (AKI) in young men. Whether aging and age-associated chronic disease may exacerbate the risk of AKI remains unclear. We evaluated plasma neutrophil gelatinase-associated lipocalin (NGAL) and serum kidney injury molecule-1 (KIM1) before and after 180min of moderate-intensity work (200W/m2) in temperate (wet-bulb globe temperature [WBGT] 16°C) and hot (32°C) environments in healthy young (n = 13, 22years) and older men (n = 12, 59years), and older men with type 2 diabetes (T2D; n = 9, 60years) or hypertension (HTN; n = 9, 60years). There were no changes in NGAL or KIM1 concentrations following prolonged work in temperate conditions in any group. Despite a similar work tolerance, the relative change in NGAL was greater in the older group when compared to the young group following exercise in the hot condition (mean difference + 82ng/mL; p < 0.001). Baseline concentrations of KIM1 were ~ 22pg/mL higher in the older relative to young group, increasing by ~ 10pg/mL in each group after exercise in the heat (both p ≤ 0.03). Despite a reduced work tolerance in the heat in older men with T2D (120 ± 40min) and HTN (108 ± 42min), elevations in NGAL and KIM1 were similar to their healthy counterparts. Age may be associated with greater renal stress following prolonged work in the heat. The similar biomarker responses in T2D and HTN compared to healthy older men, alongside reduced exercise tolerance in the heat, suggest these individuals may exhibit greater vulnerability to heat-induced AKI if work is prolonged.

Enhancing the electromagnetic shielding and mechanical properties of CF/PEEK composites via low-concentration fluff and Ni-Co alloy plating

Carbon Fiber Reinforced Composites (CFRC) are increasingly used in aircraft to minimize weight and maximize structural designability. However, CFRCs have limitations in electrical conductivity and Electromagnetic Interference (EMI) resistance. This study introduces a process to overcome these drawbacks by chemically plating Carbon Fiber (CF) fabrics with a thin layer of Nickel-Cobalt (Ni-Co) alloy, thereby improving electrical conductivity. Subsequently, Sulfonated Polyether Ether Ketone (SPEEK) was applied to the Nickel-Cobalt coated Carbon Fibers (NiCo@CF). The resulting fuzzy surface effectively enhanced the interfacial interactions within the PEEK matrix. The results showed that the tensile strength, tensile modulus, flexural strength, and flexural modulus of the composite panels treated with 0.1 wt.% SPEEK sizing significantly increased by 32.3 %, 26.0 %, 167.9 %, and 20.7 %, respectively, compared to NiCO@CF/PEEK composite panels treated with no SPEEK sizing agent. Additionally, the introduction of SPEEK fostered a shift in the primary fracture mechanism from fiber pull-out or debonding to fiber fracture. Remarkably, compared to CF/PEEK composites, the electromagnetic shielding efficiency of NiCo@CF/PEEK was increased by 88.98 %, reaching 46.15 dB. Long-term testing of the S-NiCO@CF/PEEK composites in a humid and hot environment confirmed consistent electromagnetic and mechanical properties, alongside good fatigue and aging resistance. These advances make the S-NiCO@CF/PEEK composites promising for broader applications in the aircraft and aerospace fields.

Hygroscopic and hydrothermal aging behaviors and performance deterioration mechanisms of jute yarn wound composites

The gyratory jute yarn wound composites (JYWCs) manufactured by the filament winding process show significant potential as eco-friendly alternatives to plastic pipes commonly used in outdoor settings. Ensuring the long-term service performance and durability of the JYWCs in hot and humid environments becomes critical. This study investigated the hygroscopic and hydrothermal aging behaviors of the JYWCs to elucidate their performance deterioration mechanisms. Compared with hygroscopic aging, long-term hydrothermal aging posed a more serious threat to the overall performance of the JYWCs. The jute yarns in the JYWCs experienced swelling, shrinkage, and degradation due to hygroscopic and hydrothermal aging, leading to a 47.4 % and 161.5 % increase in the void volume fraction of the JYWCs, respectively. The deterioration in the mechanical properties of the JYWCs was attributed to the attenuation of jute yarn properties, debonding of the fiber-resin matrix interface, and an increase in voids within the composites. Improving the manufacturing process to minimize voids in the JYWCs and control the pathways for moisture absorption is a highly effective strategy to enhance their long-term performance and durability.

A study of inflammatory diseases of external ear

Background: Inflammatory disease of external ear is one of the most common entities in otorhinolaryngological practice and is also frequently encountered in primary care. Due to the characteristic of its anatomical location, the external ear is exposed and easily damaged due to trauma, weathering, inflammation and environment. Objective: Objective is to study different etiological factors, clinical features, to evaluate treatment modalities, results and complications. Material and methods: A prospective observational study was conducted on 400 patients with inflammatory disease of external ear who will be undergoing ENT examination, diagnosis and treatment at Tertiary Care Center from the year 2020 to 2023. Results: Out of 400 patients, the male-female ratio is 1.2:1, the most common aetiology is bacterial but most common condition is otomycosis. Earache is the most common symptoms among the patients and 74% of the patients recovered with medical management only and complication rate was 10% only. Discussion: Commonest aetiology is otomycosis owing to hot and humid environment. Most common affected age group is younger may be because of environmental exposure. In most of the cases diagnosis was made to their clinical presentation and improved with conservative treatment so investigations were not required.

The filamentous γ-prefoldin chaperone is not essential for growth and thermal adaptation in Methanocaldococcus jannaschii.

Elucidating the role of molecular chaperones in extremely thermophilic archaea, including the gamma prefoldin (γPFD) in the deep-sea methanogen Methanocaldococcus jannaschii, is integral to understanding microbial adaptation to hot environments. This study focuses on genetically engineered knock-out and overexpression strains to evaluate the importance of γPFD in the growth and thermal tolerance of M. jannaschii. An in-depth analysis of cell growth, morphology and transcriptional responses to heat stress revealed that although the gene encoding γPFD is substantially upregulated in response to heat shock, the γPFD is not indispensable for high-temperature survival. Instead, its absence in the knock-out strain is compensated for by the upregulation of several proteolytic proteins in the absence of heat shock, nearly matching the corresponding transcription profile of selected transcripts for proteins involved in protein synthesis and folding in the wild-type strain following heat shock, using quantitative reverse-transcription PCR (RT-qPCR). These findings bridge environmental adaptation with molecular biology, underscoring the versatility of extremophiles and providing a deeper mechanistic understanding of how they cope with stress.

Hot hydrogen testing of Mo30W matrix surrogate cermets

High temperature hydrogen exposure is one of the most challenging material issues for nuclear thermal propulsion (NTP) fuel development. Under legacy NTP programs, ceramic-metallic (cermet) fuel forms with a refractory metal matrix and dispersed uranium dioxide (UO2) fuel particles were developed and showed promising performance following hot hydrogen testing. However, since the conclusion of those programs, established fabrication techniques, material feedstocks, and the ability to use highly enriched have been reduced or lost all together. In this study, a cermet consisting of a solid solution alloy of molybdenum with 30 wt percent tungsten (Mo30W) was fabricated using spark plasma sintering. Fabrication process parameters were selected to optimize the cermet microstructure using lessons learned from historic NTP programs. Yttria stabilized zirconia particles (50 to 70 % volumetric loading) were used as a fuel particle surrogate. To evaluate whether as-fabricated microstructures exhibited similar resilience as legacy cermet fuels to a hot hydrogen environment, samples were exposed to hot flowing hydrogen from 1920 to 2500 °C (∼2290 to 2770 K). The cermets performed well with minimal mass loss, minor to no cracking, and good retention of internal surrogate particles. Based on these findings, recommendations for future studies with Mo30W-UO2 cermets as an NTP fuel form are provided.