Effect Of Ambient Temperature Research Articles

Influence of ambient temperature on resting energy expenditure in metabolically healthy men and women.

It is not yet clear to what extent the physiological regulatory mechanisms that maintain core body temperature are reflected by changes in resting energy expenditure (REE). Particularly in indirect calorimetry with a canopy, the effects of short-term temperature exposures have not yet been investigated. This can be of relevance for the determination of REE in practice. This randomized crossover-study investigated the influence of a 30-minute exposure to 18°C (cool room temperature), 22°C (room temperature), 28°C (thermoneutral zone) and 38°C (heat) on REE determined by assessing the inhaled oxygen volume and the exhaled carbon dioxide volume via indirect calorimetry on four consecutive days. 32 metabolically healthy participants (16 male and 16 female, age: 25 ± 3 years, body mass index: 22.4 ± 1.6 kg/m2) were included in the study after screening examination. Lean body mass, ambient temperature and heart rate were the most important determinants (all P<0.001), and explained 61.3% of the variance in REE. A multivariate linear mixed model analysis revealed that lean mass (15.87 ± 3.66, P<0.001) and ambient temperature (P=0.001) significantly influenced REE. REE significantly differed between 18°C and 28°C (18°C: +96 ± 24 kcal/24 h, P<0.001), 22°C and 28°C (22°C: +73 ± 24 kcal/24 h, P=0.003) and 18°C and 38°C (18°C: +57 ± 23 kcal/24 h, P=0.016). Effects of ambient temperature on REE, especially cold, were detectable after only brief exposure, emphasizing the importance of performing indirect calorimetry with a canopy under controlled environmental conditions. The study was registered with the database "ClinicalTrials.gov" (NCT05505240).Web-Link: Influence of Ambient Temperature on Resting Energy Expenditure of Healthy Adults - Full Text View - ClinicalTrials.gov.

The direct and urinary electrolyte-mediated effects of ambient temperature on population blood pressure: A causal mediation analysis.

High ambient heat can directly influence blood pressure (BP) through the vasodilation of the skin vasculature and indirectly by affecting urinary volume and electrolyte levels. We evaluated the direct and urine electrolyte-mediated effects of ambient temperature on BP. We pooled 5,624 person-visit data from a community-based stepped-wedge randomized control trial in southwest coastal Bangladesh from December 2016 to May 2017. Same-day ambient temperature data from local weather stations were linked to participant BP and urine electrolytes using geo-locations of their residential addresses. We implemented causal mediation analyses using the product methods of coefficients with linear mixed models under the sequential ignorability assumption. Separate models were run for each urinary electrolyte mediator (sodium, potassium, calcium, and magnesium), followed by combined models to evaluate the natural direct and electrolyte-mediated indirect effects of temperature on BP. Models had participant-level random intercepts and were adjusted for age, sex, body mass index (BMI), religion, exercise, smoking status, sleep hours, alcohol consumption, urine creatinine, time trend, household assets, drinking water salinity, and seasonality. For the combined mediators (sodium, potassium, calcium, and magnesium), for every 5°C increase in average daily temperature: the direct effect on systolic BP was -1.42 (95% CI: -1.94, -0.92) mmHg and urine sodium mediated effect was -0.12 (95% CI: -0.20, -0.05) mmHg; while urine potassium mediated effect was 0.15 (95% CI: 0.08, 0.25) mmHg; urine calcium-mediated effect 0.06 (95% CI: 0.01, 0.12) mmHg; and urine magnesium mediated effect -0.00 (95% CI: -0.03, 0.02) mmHg. We detected similar associations for diastolic BP, pulse pressure, and mean arterial pressure. We found a significant inverse direct effect of ambient temperature on BP compared to minimally mediated urine electrolyte effects. Further studies are needed to uncover the underlying mechanisms of ambient heat and BP associations and to describe the clinical consequences of these associations.

A multi-scale multi-stage model for spray freezing of binary solutions

Spray freezing has found extensive applications in drying processes, drug delivery, and mine ventilation. The technique involves atomizing a liquefied material into a cold medium, where the resulting droplets solidify. This work presents a multi-scale model to study the spray freezing of binary mixtures. Specifically, the freezing model of a binary solution is coupled with a spray-droplet dynamics model. The spray freezing of an aqueous sucrose solution is analyzed using this framework, and parametric studies are conducted to examine the effects of droplet size, reactor length, ambient temperature, and liquid flowrate on the system performance. The results show that increasing the reactor length from 1.25 m to 4.25 m leads to a 79 % increase in the final concentration. Lowering the ambient temperature from −15 °C to −25° yields a 2.63-times bigger solid-to-liquid fraction. Additionally, increasing the flowrate from 0.0125 kg/s to 0.0625 kg/s results in a 323 % increase in heat rates.

Investigating the Synergistic Effect of Temperature and pH Dynamics on Biogas Yield from Lignocellulosic Biomass Codigested with Cow dung

The study investigated biogas production from control, pre-treated and blended waste samples, while also examining the interaction effects of ambient temperature (AT), slurry temperature (ST), and pH on the biogas volume generated from the waste samples. Experimental research design was adopted for the study. Nine biodigesters of 32L capacity labelled A-I, control (A-C), pre-treated (D-F) and blended (G-I) waste samples were used for the experiment. The digestion was carried out for a period of 35 days using the water displacement method in a laboratory scale bio-digester system. Data analysis was carried out using Excel, SPSS and STATA softwares. The methods used included descriptive statistics, multiple regression and Analysis of Variance (ANOVA). The pH and temperature readings for 35 days ranged from (6.5-8.4), AT (20-290C), ST (23-380C). Based on the study's results, there was a significant difference in the volume of biogas generated among the waste samples (F=6.4, SS=659.379, p=0.002, df=314). Specifically, significant differences were observed between the control and pre-treated samples (p=0.01) and between the control and blended samples (p=0.036). The effects of AT and ST (P=0.03) on the volume of biogas were not significant when analyzed individually; however, an interaction effect between AT and ST on biogas yield was observed. Also, pH, influenced the gas production significantly (F=3.954, p=0.021) likely due to its influence on microbial and enzymatic activity. The interaction effect showed that both temperature and pH had a combined effect on volume of biogas produced (p=0.003). These results underscore the importance of temperature and pH control in optimizing biogas production. Improved understanding of these factors could enhance anaerobic digestion processes, thus reducing greenhouse gas emissions, promoting resource efficiency and supporting circular economy principles.

Environmental Modulators on the Development of the Raccoon Roundworm (Baylisascaris procyonis): Effects of Temperature on the Embryogenesis

Members of the Ascarididae family are common zoonotic pathogens in humans and play an economic role in domestic and livestock animal husbandry. This family includes the obligatorily parasitic nematodes of the genus Baylisascaris, with the raccoon roundworm Baylisascaris procyonis being the most well-known representative. B. procyonis uses the raccoon (Procyon lotor) as its primary host and can utilize a broad range of mammals as paratenic hosts. Sexual reproduction of the adult nematodes occurs in the small intestine. Eggs are excreted into the environment through feces, where they develop into the infectious stage under suitable conditions within a few days to weeks. Infection of primary and paratenic hosts occurs through the oral ingestion of these infectious eggs. Raccoons can also become infected by ingesting infected paratenic hosts. Humans serve as accidental hosts and can suffer significant damage to organ tissues, the visual system, and the central nervous system after ingesting infectious eggs. The aim of the study was to investigate the effects of ambient temperature on embryonic development and to document the morphological changes during embryogenesis. Live specimens were collected from the raccoon intestine and incubated. Single-celled eggs were collected during this process. The eggs were decorticated and then preserved. To test the effects of ambient temperature, the eggs were incubated at 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, and 38°C and monitored at 24-hour intervals for their developmental stages. Detailed photographic documentation of the developmental stages was conducted. An increase in ambient temperature led to a reduction in development time. The temperature range within which embryogenesis proceeded to the L1 larval stage was between 10°C and 30°C. Incubation at 5°C did not produce L1 larvae even after 11 months. Incubation at 35°C and 38°C resulted in the complete degeneration of the eggs before reaching the L1 larval stage.

Optimization of the blow-off efficiency of kerosene adhering to the inner wall of chambers with complex structures

The research objective of this paper is to obtain an efficient space engine chamber wall adherent kerosene blow-off solution, the research methodology uses computational fluid dynamics method and experiments are conducted to verify the numerical calculation accuracy. The effect of gas pressure, gas temperature, ambient temperature, and gas type on the blow-off efficiency was obtained, in which increasing the pressure and temperature of the blow-off gas increased the treatment efficiency by 14.16% and 9.85%, respectively, and the blow-off efficiency was significantly improved. Increasing the operating ambient temperature and changing the type of purge gas increased the treatment efficiency by 4.76% and 5.88%, respectively. Finally, the removal scheme was optimized by increasing the blow-off gas pressure and temperature, and the treatment efficiency of the optimized scheme was improved by 37.5% compared to the original scheme. The findings of this paper provide important guidance for the efficient blow-off off of kerosene adhering to the inner wall of complex structural cavities.

The effect of ambient temperature and relative humidity in postpartum dairy cows on productive and reproductive performance and biochemical blood indices in the subsequent lactation

Abstract This study evaluated the effects of ambient temperature (T) and relative humidity (RH) during the postpartum transition period on dairy cows’ milk performance, fertility, and immunometabolic blood indices in the subsequent lactation. A total of 100 Polish Holstein-Friesian cows originating from five commercial dairy farms were categorized into three groups based on average T (&lt;16 °C, 16-20 °C and &gt;20 °C) and RH (&lt;65%, 65-75%, and &gt;75%) on the calving day (0d), and days 7, 14, 21 after calving. With increasing T and RH postpartum, the average daily milk yield during the first 150 days in milk decreased gradually, and the differences between T &lt;16 °C and &gt;20 °C and RH &lt;65% and &gt;75% groups were approx. 3.48 and 2.78 kg, respectively. Milk of cows exposed to increased T and RH was lower in protein, and lactose and higher in fat, milk urea, and somatic cell count. It was also characterized by altered fat composition. Ambient T during the postpartum period had a negative effect on cows’ fertility, which, however, was not affected by RH. The increasing T from &lt;16 °C to &gt;20 °C resulted in the later manifestation of the first estrous (by 27.7 days), a more extended artificial insemination service period (by 19.4 days), a higher number of insemination services per conception (by 0.92 on average), more days open (by 43.3 days), and a longer calving interval (by 43.3 days). Within ranges used in this study, increasing T and RH during the period from d 0 to d 14 postpartum led to decreased body condition score on day 21 by approx. 0.48 and 0.51 points, respectively. Furthermore, T and RH on a calving day were associated with altered biochemical blood indices on d 21 after calving, indicating a more severe negative energy balance and a state of inflammation. The results of this study suggest that dairy cows that calve when T &gt;16 °C should be provided cooling to ensure optimal environmental conditions for high milk production and prevent economic losses associated with reduced milk yield and low fertility.

Association between nighttime and daytime ambient temperature and insomnia using national emergency department database in the capital city of South Korea.

Insomnia is a growing health concern globally, with significant implications for public health. Most studies have primarily focused on the effects of nighttime temperatures on sleep problems. However, there is a lack of studies comparing nighttime temperatures with daytime temperatures, which are more closely related to daily life activities. This study aimed to explore a short-term association of nighttime and daytime ambient temperature with emergency department (ED) visits for insomnia in the capital city of South Korea. A time-stratified case-crossover design was employed using a conditional logistic regression model. A distributed lag non-linear model was utilized to explore potential non-linear and lag effects of ambient temperature on ED visits for insomnia. Odds ratio (OR) for temperature with maximum ED visits for insomnia (MaxIT) and that for temperature with minimum ED visits for insomnia (MinIT) were calculated and compared. We observed significant associations at high temperatures for both nighttime and daytime (nighttime: 25.0℃ (94.1%) [OR: 1.82, 95% CIs: 1.31-2.55], daytime: 30.6℃ (99.0%) [OR: 2.13, 95% CIs: 1.49-3.06]) compared to MinIT (-8.5℃ (2.7%) and - 8.4℃ (1.0%), respectively). Subgroup analyses found significant associations at high temperatures in females, individuals aged 35-49, and those without comorbidities, and during spring, fall, and winter, for both daytime and nighttime. Our findings provide insights for proactive public health strategies for managing insomnia during global temperature rise.

Effects of ambient temperature on mental and neurological conditions in older adults: A systematic review and meta-analysis

BackgroundEmerging research has suggested a link between ambient temperature and mental and neurological conditions such as depression and dementia. This systematic review aims to summarize the epidemiological evidence on the effects of ambient temperature on mental and neurological conditions in older adults, who may be more vulnerable to temperature-related health effects compared to younger individuals. MethodsA systematic search was conducted in PubMed, Ovid/Embase, Web of Science, and Ovid/PsycINFO on July 17, 2023, and updated on July 31, 2024. We included epidemiological studies investigating the association between ambient temperature exposures and numerous mental and neurological conditions in populations aged 60 years and older. Exclusions were made for studies on indoor or controlled exposure, suicide, substance abuse, those not published as peer-reviewed journal articles, or those not written in English. The risk of bias of included studies was assessed using a tool developed by the World Health Organization (WHO). Qualitative synthesis was performed on all eligible studies, and random-effects meta-analyses were conducted on groups of at least four studies sharing similar study design, exposure metric, and health outcome. The certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework modified by the WHO. ResultsFrom 16,786 screened articles, 76 studies were deemed eligible, primarily from mainland China and North America. There was notable heterogeneity in study variables and methodologies. The most commonly used exposure metrics were daily absolute temperature and heat waves, and time-series and case-crossover analyses were the most frequently employed study designs. Meta-analysis of four studies on the effect of a 1 °C increase in temperature on hospital admissions/visits for mental disorders showed a pooled risk ratio (RR) of 1.014 (95 % Confidence Interval, CI: 1.001, 1.026). Comparing heat wave days to non-heat wave days, pooled effect estimates showed increased risk in hospital admissions/visits (RR: 1.269; 95 % CI: 1.030, 1.564; six studies) and mortality related to mental disorders (RR: 1.266; 95 % CI: 0.956, 1.678; four studies). Despite the limited number of studies on cold exposures, they consistently reported that lower temperatures were associated with an increased risk of various mental and neurological conditions. ConclusionsThis review presents epidemiological evidence of the adverse impacts of ambient temperature exposures, such as high temperatures and heat waves, on mental and neurological conditions among the older adult population, with overall moderate certainty. The findings highlight the need for greater attention to the mental and neurological health of older adults in the context of climate change and population aging.Registration number (PROSPERO ID): CRD42023428137.

Multiphysics Modeling of Power Transmission Line Failures Across Four US States

The failure of overhead transmission lines in the United States can lead to significant economic losses and widespread blackouts, affecting the lives of millions. This study focuses on analyzing the failure of transmission lines, specifically considering the effects of wind, ambient temperature, and current demands, incorporating minimal and significant pre-existing damage. We propose a multiphysics framework to analyze the transmission line failures across sensitive and affected states of the United States, integrating historical data on wind and ambient temperature. By combining numerical simulation with historical data analysis, our research assesses the impact of varying environmental conditions on the reliability of transmission lines. Our methodology begins with a deterministic approach to model temperature and damage evolution, using phase-field modeling for fatigue and damage coupled with electrical and thermal models. Later, we adopt the probability collocation method to investigate the stochastic behavior of the system, enhancing our understanding of uncertainties in model parameters, conducting sensitivity analysis to identify the most significant model parameters, and estimating the probability of failures over time. This approach allows for a comprehensive analysis of factors affecting transmission line reliability, contributing valuable insights into improving power line’s resilience against environmental conditions.

Combined Effect of Ambient Temperature and Relative Humidity on Skin Aging Phenotypes in the Era of Climate Change: Results From an Indian Cohort Study.

Background: There is no doubt that global warming, with its extreme heat events, is having an increasing impact on human health. Heat is not independent of ambient temperature but acts synergistically with relative humidity (RH) to increase the risk of several diseases, such as cardiovascular and pulmonary diseases. Although the skin is the organ in direct contact with the environment, it is currently unknown whether skin health is similarly affected. Objective: While mechanistic studies have demonstrated the mechanism of thermal aging, this is the first epidemiological study to investigate the effect of long-term exposure to heat index (HI) as a combined function of elevated ambient temperature and RH on skin aging phenotypes in Indian women. Methods: The skin aging phenotypes of 1510 Indian women were assessed using the Score of Intrinsic and Extrinsic Skin Aging (SCINEXA™) scoring tool. We used data on ambient temperature and RH, combined into an HI with solar ultraviolet radiation (UVR), and air pollution (particulate matter <2.5 µm [PM2.5]; nitrogen dioxide [NO2]) from secondary data sources with a 5-year mean residential exposure window. An adjusted ordinal multivariate logistic regression model was used to assess the effects of HI on skin aging phenotypes. Results: HI increased pigmentation such as hyperpigmented macula on the forehead (odds ratios [OR]: 1.31, 95% confidence interval [CI]: 1.12, 1.54) and coarse wrinkles such as crow's feet (OR: 1.17, 95% CI: 1.05, 1.30) and under-eye wrinkles (OR: 1.3, 95% CI: 1.15, 1.47). These associations were robust to the confounding effects of solar UVR and age. Prolonged exposure to extreme heat, as indicated by high HI, contributes to skin aging phenotypes. Conclusion: Thus, ambient temperature and RH are important factors in assessing the skin aging exposome.

The effect of different mission profiles and ambient temperature on the lifetime of boost converter IGBT with a robust controller in a hybrid electric vehicle

AbstractThe reliability of power electronic converters is one of the essential issues in designing of electric vehicles. This paper estimates the lifetime of the boost converter switch by Semikron and Coffin‐Manson models for two common failure mechanisms of Bond wire and Base plate solder, respectively. Four mission profiles based on the Artemis standard are applied to hybrid electrical vehicle model to determine unidirectional output power. Kharitonov's theory is used to design a robust controller to handle the uncertainty raised by different power cycles of the electric vehicle and the parameters of the converter during simulation. Stability of converter is achieved during simulation by identifying simple proportional integral controller coefficients with Kharitonov's theorem. A prototype 230 W boost converter is designed and utilized to validate average model and switch loss calculation relationships. The lifetime results indicate that the number of cycles, and the average and the maximum junction temperature have a more impact than the duration of the drive cycle on the lifetime of the converter. A mixed mission profile is considered to investigate the effect of sudden change in driving modes and speed on total consumed life and lifetime to enhance the study's applicability. Lifetime of switch is decreased significantly in mixed mode in comparison with other mission profiles in the same driving time. Furthermore, the motorway mission profile has 53%, 39.6%, and 160% less total consumed life in comparison with the urban, rural and mixed mission profiles, respectively. In addition, the effect of ambient temperature changes on IGBT lifetime has been investigated for four mission profiles. While motorway had the least total consumed life in 25°C, the urban had better performance in comparison with other mission profiles from 25 to 55°C.

Unveiling the effect of cycle time and ambient temperature on the failure mechanisms of commercial LiCoO2/artificial graphite pouch cells

Many efforts have been devoted to investigate failure mechanisms of LiCoO2-based lithium-ion batteries at ≥4.55 vs. Li+/Li. However, most of these works are conducted on coin-type half-cells and rarely consider the effects of cycle time and ambient temperature on mechanisms. So, it calls an alarming demand for making clear the cyclabilities of cells at different temperatures, then differentiating the root causes for their capacity degradations. Herein, the cyclabilities of an ∼3.1 Ah commercial LiCoO2/artificial graphite pouch cell at 3–4.45 V are compared at 25 and 60 °C. It is found that the cycle lives at 25 and 60 °C are 2944 and 122 cycles, respectively. The structural variations of the cycled electrodes are systematically studied. Results reveal that the main cause for the capacity beginning to decline after 3000 cycles at 25 °C is the damage of LiCoO2 structure, while its impedance growth and other side reactions are not severe. Differently, the capacity dropping upon cycling at 60 °C is caused by the parasitic reactions including successive electrolyte decomposition, severe cobalt dissolution and Li deposition. Obviously, these findings can provide a theoretical basis for further optimizing of LiCoO2 cells.

Operational vehicle state of health estimation framework based on local-global attention mechanism

The state of health (SOH) of electric vehicles directly correlates with operational safety and driving range. Accurate assessment of SOH is crucial for improving the safety and reliability of electric vehicles. This article proposes a novel SOH estimation framework based on the local-global attention mechanism (L-G-A) and real-world incomplete charging processes. Firstly, an analysis of the charging modes is conducted. Specifically, the average value of capacity is calculated for multiple constant current segments as the reference capacity, and the effect of ambient temperature on charging efficiency and battery capacity is considered. Subsequently, aging characteristics of interval capacities are extracted through incremental capacity analysis. To investigate the impact of different usage patterns on battery degradation during daily use by vehicle owners, the historical cycle charging segments are categorized based on segment similarity. Then, the L-G-A model is established by utilizing convolutional layers to extract local-scale temporal information and computing global attention scores based on degradation information between each segment and across classes. The experimental results demonstrate that the proposed framework has the highest estimation accuracy with mean absolute error and root mean square error of 0.069 % and 0.084 %, respectively, which outperforms the traditional LSTM, CNN, and SVR models in terms of accuracy of SOH evaluation.

Evaluating the Influence of Thin Film of Water on the Frequency Dependences of Transmission Line S-Parameters at Positive and Negative Temperatures

Relevance. Provision of reliable and uninterrupted radio communication is critically important under changing climatic conditions of its operation. The combined effect of temperature and humidity can lead to changes in the electrical characteristics of transceiving devices and thereby disrupt the communication channel. In difficult climatic conditions of operation, due to constant temperature changes on the surface of the printed circuit boards, which are part of them, condensation can form, affecting the performance of the entire device. In this regard, the electrical characteristics change, which must be taken into account when designing critical REE. When designing transmission lines on printed circuit boards, it is reasonable to evaluate climatic impacts on it in a wide frequency range, which requires the development of new models and methods that allow taking into account these impacts.Goal of the work: to evaluate the influence of the temperature of a thin film of water on the surface of a microstrip transmission line on its frequency dependences of S-parameters. Finite element methods and laboratory experiment were used.Results. A methodology to account for the effects of ambient temperature and humidity on the electrical characteristics of a microstrip transmission line (MTL) is presented, which allows evaluating the variation of the S-parameters of the line over wide ranges of frequencies, air temperature and humidity, as well as the chemical composition of the environment. The S-parameters of water in a container placed inside a coaxial chamber are measured over the frequency and temperature ranges of 10 MHz to 12 GHz and minus 50 to 100℃, respectively. Using the presented model, the frequency dependences of the electrical conductivity of water at different temperatures are calculated. It is shown that at positive temperature, the electrical conductivity can reach 6.5 Sm/m and at negative temperature it can reach 1.3 Sm/m. Using the developed methodology, the influence of different water electrical conductivity on the S-parameters of MTLs is evaluated. The influence of water and ice layer thickness on the S-parameters of MTLs was shown. It is found that models describing the electrical conductivity of water have an excellent influence on the electrical parameters of the transmission line. Novelty. A method of accounting for the influence of ambient temperature and humidity on the S-parameters of the transmission line is presented, which is characterized by the use of a model of water conductivity based on insertion losses calculated from the measured S-parameters of a coaxial chamber with water in the container when its temperature is changed. Practical significance: a model and a methodology for taking into account the impact of temperature and humidity of the environment on the MTL characteristics are presented, allowing estimating the S-parameters of the line in a wide range of frequencies, air temperature and humidity, as well as the chemical composition of the environment.

A study on the reduction of high-temperature in the high-pressure piping system of civil aircraft

Abstract For the study of the bleed air flow process in high-pressure pipelines, theoretical analysis and numerical simulation were used to investigate the temperature drop problem in the pipelines. The effect of bleed air and ambient temperatures on the performance of temperature drop in high-pressure pipelines was discussed in detail. The performance of pipeline insulation before and after applying the insulation layer was also discussed. The results show that the higher bleed air temperature and lower ambient temperature obviously cause a greater drop in the bleed air temperature drop. The entrance section of the pipeline is approximately five times the l/d range. Applying the insulation layer can effectively reduce the drop in pipeline temperature. Generally, the air insulation layer can reduce the temperature drop of high-pressure pipeline gas by 25%. If further reduction is required, the vacuum insulation layer can be applied.

Numerical simulation and risk assessment of toluene tank leakage in petrochemical industries, China.

Large-capacity toluene storage tank leakage accidents can lead to severe casualties and environmental damage. In this study, numerical simulation of the toluene leakage accidents is performed using PHAST and ALOHA softwares across 16 scenarios. The present research focuses on the dispersion of toluene lethal and toxicity clouds, as well as the associated risks from vapor cloud explosions and pool fires resulting from the large-capacity toluene storage tank leakage. Meanwhile, the effects of influential factors such as leakage height, wind speed, ambient temperature, and atmospheric stability on toluene leakage accidents are also discussed, and then the worst-case scenario of the toluene leakage accident is obtained. The effects of wind speed, ambient temperature, leakage height, and atmospheric stability on outcomes such as toxic clouds, vapor dispersion, explosions, and pool fires are also analyzed. The result reveals that toxic cloud dispersion increases with ambient temperature, while the impact of vapor cloud explosions and pool fires decreases with the increase of leak heights. Wind speed significantly affects pool fire spread. The influential factors related to maximizing hazard range including low leak heights, low wind speeds, high temperatures, and stable conditions are obtained. Risk analysis indicates that vapor cloud explosions significantly impact outdoor potential loss of life (PLLoutdoor) compared with other incidents. Scenario 4 within a directional range from 33.8 to 56.3° shows the highest incident frequencies, highlighting its importance for risk monitoring. These findings are crucial for enhancing emergency response strategies and safety protocols in industrial safety management.

The effect of ambient temperature on dynamic energy–exergy analysis of a d-type boiler during cold start-up

The effect of ambient temperature on dynamic energy–exergy analysis of a d-type boiler during cold start-up

On the performance and thermal stability of solar cell based on CIGS-Sb2S3 combination with >35 % power conversion efficiency

This study presents a solar cell design utilizing a CIGS (copper-indium-gallium-selenide) absorber and Sb2S3 (antimony trisulfide) back surface field (BSF) layers, targeting high photovoltaic (PV) performance with an emphasis on minimum possible effect of ambient temperature. We simulated a solar cell design consisting of zinc oxide, surface defect layer, zinc sulfide, CIGS layer, and an Sb2S3 layer using SCAPS-1D software. Our findings indicate that 200 nm Sb2S3 layer and a 1600 nm CIGS layer is the preferred combination for achieving high PV performance and appropriate J-V characteristics of the proposed solar cell. For this design, the achieved values of VOC (open circuit voltage), JSC (short circuit current density), PCE (power conversion efficiency), and fill factor (FF) are 1.069V, 42.08 mA/cm2, 35.94 %, and 80.31 %, respectively. The PV performance of the proposed solar cell is substantially better than the solar cell design without BSF layer as well as recently reported (2023-24) solar cell designs. This study further examines the impact of elevated ambient temperatures (295–360 K) on the PV performance. Our simulation results show that operating the proposed solar cell at moderately elevated temperatures is not a significant issue owing to small power temperature coefficient (−0.034 % per K), which is comparable to that of commercially available solar cells. These findings are expected to contribute to the ongoing advancement of PV solar cells, aiming for higher PCE and improved stability, including thermal stability. Proposed solar cell with low PTC and high PCE can be suitable for space applications where temperature fluctuation is severe, as well as in tropical areas.

Dynamic planning of crowd evacuation path for metro station based on Dynamic Avoid Smoke A-Star algorithm

Considerable casualties can easily be caused once a fire occurs in a metro station, and a safe and effective evacuation path in time should be provided, taking on critical significance in the rapid evacuation of the crowd. In existing research, crowd evacuation paths have been generally planned without considering the fire environment and the real-time effect of fire products on the evacuation paths, such that the planned paths do not fit the realistic environment of crowd evacuation. An algorithm is proposed in this study to dynamically plan evacuation paths in fire scenarios in metro stations. First, the equivalent length of the path under the effect of fire on evacuation speed is determined in accordance with the effects of ambient temperature, visibility, and CO concentration, and then the fire risk model is built. Second, the fire risk model is incorporated into the A-Star algorithm, and the evaluation function of the A-Star algorithm is optimized, such that the determined path is capable of avoiding areas with higher fire risk. Subsequently, a dynamic update mechanism considering time factor is introduced to update the search environment information data of the algorithm in real time for dynamic path planning, with the aim of coping with the dynamically changing fire environment. Lastly, the A-Star algorithm is optimized, and the Dynamic Avoid-Smoke A-Star (DASA-Star) algorithm is built. As indicated by the simulation results, the DASA-Star algorithm is capable of making a trade-off between the fire risk and geometric length of the path in an underground station fire scenario and achieving dynamic planning of evacuation paths based on FDS fire simulation results. Accordingly, the algorithm conforms to the real-time requirements of path planning under fire conditions, and it is capable of more effectively planning the optimal evacuation path under the effect of fire.