Temperatures In Excess Research Articles

Recent Trends in Extreme Temperature Events Across the Contiguous United States

ABSTRACTExtreme heat events (EHEs) are becoming prevalent across the globe and are a major factor in terms of temperature‐related mortality in the United States (US). In this study, we compare trends in extreme temperature events (ETEs) across the Contiguous US, from 3 reanalysis products, namely: European Centre for Medium‐Range Weather Forecasts Reanalysis Version 5 (ERA5), Modern‐Era Retrospective Analysis for Research and Applications Version 2 (MERRA2) and North American Regional Reanalysis (NARR). We focused on the trends (1980–2022) in absolute extreme heat and cold events (ECE) as well as seasonally relative extreme heat and cold events (REHE and RECE). ETEs are defined based on a duration‐intensity metric calculated from excess apparent temperature factors, based on the exceedance of apparent temperature beyond local percentile thresholds while incorporating an acclimatisation factor. Our results show that the reanalysis data sets generally produced consistent climatology of ETEs, though with some inconsistencies in their number and spatial distribution. ETE trends in the study region are spatially heterogeneous and were more consistent between MERRA2 and ERA5. Nonetheless, all data sets agree that the frequency of EHEs is significantly increasing in the western parts of the US, whereas REHEs are significantly increasing in the southern parts. The highest increase in the frequency of EHEs occurs in southern California and Nevada, while REHE trends are maximal in Florida. RECEs are significantly decreasing more in spatial scale and magnitude than ECEs, especially towards the coastal regions. The highest decrease in RECEs is in Florida peninsula, southern California and Nevada. The data sets show inconsistency in ECE trends. Trends in excess temperature factors further indicated that extreme cold conditions are decreasing faster compared to the increasing trends of extreme heat conditions. Our findings highlight the need for improving the monitoring of ETEs across the US and for policies that mitigate the impact of ETEs on biological systems.

Development of a low-cost, 3-D printed, aspirated air-temperature measurement radiation shield

Abstract Accurate measurement of ambient air temperature is critical to numerous applications. This task is complicated by solar radiation which can heat the air-temperature sensor body, causing it to record temperatures in excess of the true air temperature. The standard way to protect against this interference is to house the sensors in passive radiation shields which block the majority of solar radiation. However, solar radiation still heats the shield body which can then heat the sensor, causing measurement errors under low-wind conditions. An alternative method is to aspirate the sensor using a fan to force air movement over the sensor body. Aspirated temperature sensing units are commercially available, but they can be expensive and consume a significant amount of power. Here, we present the design and initial rigorous testing of a low-cost, low-power aspirated temperature sensing unit designed to integrate with any low-cost distributed sensor platform. The design uses a freely available, custom designed 3-D printed housing that enables rapid assembly. The new, open source unit is shown to perform as well as passive shields and commercial aspirated shields of significantly higher cost. This success shows the potential of leveraging 3-D printing technologies for other housing units. Further testing is needed to better quantify long-term robustness of the shield.

Enhancing heat and moisture transfer of porous fabrics using arrayed opposed jets: Experimental and numerical investigations

Achieving rapid fabric drying and ensuring a uniform distribution of surface temperature and moisture is essential for the post-processing stage in printing and dyeing. Although jet technology is commonly used to enhance heat transfer processes, the mechanism of heat and moisture transfer using array opposed jet for fabric drying is still unclear. This paper proposes that using opposed jet to enhance the drying process for four different fabric structural types, the influence of jet Reynolds number and excess temperature on the change of fabric moisture content was analyzed using experimental methods, then by defining the fabric as a porous medium containing two-phase components, the flow characteristics and temperature field distribution of the opposed jet were obtained using numerical methods. The results indicated that the four different structural types of fabrics exhibited similar heat-moisture transfer characteristics under the air supply mode of the opposed jet. Furthermore, the critical evaporation temperature of fabrics with hygroscopic properties was higher than that of non-hygroscopic fabrics. When the Reynolds number increased from 649.4 to 2165.3 and the excess temperature increased from 40 ℃ to 70 ℃, the drying time was shortened by a maximum of 56.2 % and 25.5 %, respectively. Under the impact of the array opposed jet, the thermal boundary layer on the fabric surface was thinned, and the local Nusselt number presented different peaks along the length direction of the impinging surface. Within the range of operating conditions considered, at a jet wind speed of 4.5 m/s and an excess temperature of 70 ℃, the maximum surface drying rate of the fabric was achieved. The relative deviations of heat flux and mass flux on the impact surface are all within 10 %. This study provides a theoretical basis for the structural design and drying mechanism exploration of fabric drying equipment.

Microstructure and Phase Equilibria in BCC-B2 Nb-Ti-Ru Refractory Superalloys.

Refractory superalloys (RSAs) are promising candidates for high-temperature, high-strength applications. Two-phase RSAs containing body-centered cubic (BCC) and ordered B2 phases are among the more promising candidates. Systems containing Ru-based B2 precipitates exhibit stable two-phase microstructures at temperatures in excess of 1600 °C. The present study experimentally investigated one potential foundational ternary system for these alloys, Nb-Ti-Ru. Two alloys, (Nb3Ti)0.85Ru0.15 and (Nb4Ti)0.85Ru0.15, were studied to determine phase equilibria and properties at temperatures between 900 °C and 1300 °C. The B2 phase was found to be dominated by RuTi ordering, although considerable Nb solubility was observed up to 18 mol %. The Nb-rich BCC matrix contained up to 15 mol % Ru and 20 mol % Ti. Although a two-phase microstructure of B2 precipitates in a BCC matrix was confirmed, the distribution of elements in the two phases resulted in a larger lattice misfit than expected. The results obtained in this investigation provide valuable information for the future development of RSAs utilizing Ru-based B2 strengthening precipitates.

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.

Research on Carbon Footprint Reduction During Hydrogen Co-Combustion in a Turbojet Engine

The paper presents experimental studies on the effect of co-combustion of aviation kerosene with hydrogen in the GTM400 turbojet engine on the change in the carbon footprint generated by the engine in relation to its standard operation without hydrogen in the fuel. This research is in line with current research and development trends carried out in the EU, linking them to the issues of the European Green Deal, the Fit for 55 directive and current environmental trends in aviation and energy. The main objective of the research was to check the effect of hydrogen co-combustion in a turbojet engine on the change of the carbon footprint, while a secondary objective was to verify the impact of higher exhaust gas temperatures generated by the new, high-calorific fuel on the secondary generation of nitrogen oxides (NOx), especially in the thermal mechanism, as an undesirable effect. The research shows that the co-combustion of hydrogen with aviation kerosene in a turbojet engine reduces the carbon footprint (reduction of CO2 maximum of 15% and CO emissions maximum of 24%), but also increases the emission of nitrogen oxides (NOx) maximum of 58%, including those generated in the thermal mechanism (significant increase in the temperature of exhaust gases), moreover, the increase in nitrogen oxide emissions is proportional to the amount of co-combusted hydrogen, which is directly related to the stoichiometry of the combustion process. The main conclusion of the research is that technologies for the combustion or co-combustion of hydrogen in turbojet engines require further research and development, mainly on the side of the use of excess exhaust gas temperature generated during combustion and methods of reducing secondary nitrogen oxides.

Annealing Temperature Effect on TeO2 Thin Films for Optical Detection Devices

Physical vapor deposition method was used for the preparation of nanostructured TeO2. Different morphologies of TeO2 are synthesized using a physical evaporation method with Te powder as the source material and quartz SiO2 as the growth substrates. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and ultraviolet-visible (UV–Vis) analyses are used to characterize the structural, morphological, and optical properties of the TeO2 products obtained. By varying the annealing temperature, different morphology of TeO2 structures is investigated. TeO2 nanostructure progress is initiated by the crystallization of particles. Different temperatures have different effects on structures, which are discussed. The films as deposited nature was amorphous; crystallization occurred at a higher annealing temperature (175 oC). With an increase in annealing temperature, the TeO2 films grain size increased. The research also points to the impact of post-deposition thermal annealing temperatures in excess of 100 °C in enhancing TeO2 film characteristics.

Cold Tolerance Assay Reveals Evidence of Climate Adaptation Among American Elm (Ulmus americana L.) Genotypes

T he American elm (Ulmus americana L.), once a dominant species in North American floodplain forests, has suffered significant population declines due to Dutch elm disease (DED). Despite this, some elms persist, potentially exhibiting disease resistance and climate-adaptive traits that could facilitate restoration. Understanding these traits is crucial for selecting genotypes suited to current and future climatic conditions, particularly in colder regions. This study evaluated the mid-winter cold tolerance of American elm genotypes across a climatic gradient to ascertain evidence of local climate adaptation. We used relative electrolyte leakage (REL) to assess mid-winter cold tolerance of current-year shoots on eleven survivor genotypes from New England and one susceptible, control genotype from Ohio. The lethal temperature, at which 50% of cellular leakage occurs (LT50), was determined and compared with 30-year climate data to identify potential climate adaptation. Genotypes from colder regions exhibited greater cold hardiness, indicating local adaptation to climate. Observed mid-winter LT50 values (−42.8 °C to −37.7 °C) were in excess of the 30-year minimum air temperature, even at the coldest source location. This calls into question whether mid-winter cold tolerance is the critical period for injury to American elm and more attention should be given to environmental conditions that cause de-acclimation to cold. By understanding the adaptive capacity of American elm, managers can better select mother trees for regional seed orchards, ensuring the long-term success of restoration initiatives.

Heat stress: a major threat to ruminant reproduction and mitigating strategies.

Stress is an external event or condition that puts pressure on a biological system. Heat stress is defined as the combination of internal and external factors acting on an animal to cause an increase in body temperature and elicit a physiological response. Heat stress is a set of conditions caused by overexposure to or overexertion at excess ambient temperature and leads to the inability of animals to dissipate enough heat to sustain homeostasis. Heat exhaustion, heat stroke, and cramps are among the symptoms. For the majority of mammalian species, including ruminants, heat stress has a negative impact on physiological, reproductive, and nutritional requirements. Reproductive functions, including the male and female reproductive systems, are negatively affected by heat stress. It decreases libido and spermatogenic activity in males and negatively affects follicle development, oogenesis, oocyte maturation, fertilization, implantation, and embryo-fetal development in females. These effects lead to a decrease in the rate of reproduction and financial losses for the livestock industry. Understanding the impact of heat stress on reproductive tissues will aid in the development of strategies for preventing heat stress and improving reproductive functions. Modification of the microenvironment, nutritional control, genetic development of heat-tolerant breeds, hormonal treatment, estrous synchronization, timed artificial insemination, and embryo transfer are among the strategies used to reduce the detrimental effects of heat stress on reproduction. These strategies may also increase the likelihood of establishing pregnancy in farm animals.

Prediction of Heat Transfer in a Hybrid Solar–Thermal–Photovoltaic Heat Exchanger Using Computational Fluid Dynamics

Solar energy is one of the main renewable energy resources due to its abundance. It can be used for two purposes, thermal or photovoltaic applications. However, when the resource obtained is mixed, it is called photovoltaic thermal hybrid, where the solar panels generate electricity and are provided with a heat exchanger to absorb energy through a water flow. This is one of the techniques used by the scientific community to reduce the excess temperature generated by solar radiation in the cells, improving the electrical efficiency of photovoltaic systems and obtaining fluid with higher temperature. In this work, the thermal behavior of a heat exchanger equipped with fins in its interior to increase the thermal efficiency of the system was analyzed using CFD (Computational Fluid Dynamics). The results showed that the average fluid outlet temperature was 75.31 °C, considering an incident irradiance of 1067 W/m2 and a fluid inlet temperature of 27 °C. The operating conditions were obtained from published experimental studies, achieving 97.7% similarity between the two. This was due to the boundary conditions of the heat flux (1067 W/m2) impinging directly on the coupled cells and the heat exchanger in a working area of 0.22 m2.

Projections of Climate Change Impact on Acute Heat Illnesses in Taiwan: Case-Crossover Study.

With global warming, the number of days with extreme heat is expected to increase and may cause more acute heat illnesses. While decreasing emissions may mitigate the climate impacts, its effectiveness in reducing acute heat illnesses remains uncertain. Taiwan has established a real-time epidemic surveillance and early warning system to monitor acute heat illnesses since January 1, 2011. Predicting the number of acute heat illnesses requires forecasting temperature changes that are influenced by adaptation policies. The aim of this study was to estimate the changes in the number of acute heat illnesses under different adaptation policies. We obtained the numbers of acute heat illnesses in Taiwan from January 2011 to July 2023 using emergency department visit data from the real-time epidemic surveillance and early warning system. We used segmented linear regression to identify the join point as a nonoptimal temperature threshold. We projected the temperature distribution and excess acute heat illnesses through the end of the century when Taiwan adopts the "Sustainability (shared socioeconomic pathways 1-2.6 [SSP1-2.6])," "Middle of the road (SSP2-4.5)," "Regional rivalry (SSP3-7.0)," and "Fossil-fueled development (SSP5-8.5)" scenarios. Distributed lag nonlinear models were used to analyze the attributable number (AN) and attributable fraction (AF) of acute heat illnesses caused by nonoptimal temperature. We enrolled a total of 28,661 patients with a mean age of 44.5 (SD 15.3) years up to July 2023, of whom 21,619 (75.4%) were male patients. The nonoptimal temperature was 27 °C. The relative risk of acute heat illnesses with a 1-degree increase in mean temperature was 1.71 (95% CI 1.63-1.79). In the SSP5-8.5 worst-case scenario, the mean temperature was projected to rise by +5.8 °C (SD 0.26), with the AN and AF of acute heat illnesses above nonoptimal temperature being 19,021 (95% CI 2249-35,792) and 89.9% (95% CI 89.3%-90.5%) by 2090-2099. However, if Taiwan adopts the Sustainability SSP1-2.6 scenario, the AN and AF of acute heat illnesses due to nonoptimal temperature will be reduced to 12,468 (95% CI 3233-21,704) and 62.1% (95% CI 61.2-63.1). Adopting sustainable development policies can help mitigate the risk of acute heat illnesses caused by global warming.

Experimental investigation on maximum ceiling temperature and longitudinal attenuation in a closed tunnel with an inclined shaft

For tunnel fires with open and closed tunnel ends, the smoke flow pattern and air supply conditions vary considerably, resulting in different maximum excess ceiling temperature (ΔTmax) and its longitudinal distribution (ΔTx). However, few studies have focused on the tunnel closed at both ends with an inclined shaft (typical tunnel structure during construction). Hence, tunnel model 1 (tunnel closed at both ends with an inclined shaft) and tunnel model 2 (tunnel open at both ends) are built for comparison and analysis. The results show that tunnel model 1 has higher ceiling temperatures and slower attenuation than tunnel model 2. Therefore, the ΔTx in tunnel model 1 needs to be re-analyzed in detail. Different inclined shaft slopes, fire heat release rates, longitudinal and vertical fire positions are considered. In tunnel model 1, for h (lifting height of burner surface) = 0, the ΔTmax value tends to be constant for the same heat release rate, irrespective of the longitudinal fire position. For h = 5 cm, the ΔTmax value takes on a rising trend with the fire moving downstream. Moreover, the inclined shaft slope within this study has little influence on ΔTx. As the fire moves downstream, the downstream ΔTx/ΔTmax value decreases more rapidly. From h = 0 to h = 5 cm, the value of ΔTx/ΔTmax drops slightly faster, but the gap is small and can be ignored. Finally, the experimental correlations are proposed to estimate the longitudinal ceiling temperature distribution in a closed tunnel with an inclined shaft.

Temperature dependence of the low-frequency noise in AlGaN/GaN fin field effect transistors

Low-frequency (LF) noise measurements are compared for Schottky-gate AlGaN/GaN heterostructure planar and fin field-effect transistors (FinFETs) as functions of gate voltage and measuring temperature. The noise of each device type is consistent with a carrier number fluctuation model. Similar effective defect-energy Eo distributions are derived for each of the two device architectures from measurements of excess drain-voltage noise-power spectral density vs temperature from 80 to 380 K. Defect- and/or impurity-related peaks are observed in the inferred energy distributions for Eo < 0.2 eV, Eo ≈ 0.45 eV, and Eo > 0.6 eV. Significant contributions to the LF noise are inferred for nitrogen vacancies and ON and FeGa impurity complexes. Ga dangling bonds at fin interfaces with gate metal are likely candidates for enhanced noise observed in FinFETs, relative to planar devices. Reducing the concentrations of these defects and impurity complexes should reduce the LF noise and enhance the performance, reliability, and radiation tolerance of GaN-based high electron mobility transistors.

Understanding excess mortality in 2022: The dual impact of COVID-19 and heatwaves on the Italian elderly population

In this study, we employ a comprehensive approach to model the concurrent effects of the COVID-19 epidemic and heatwaves on all-cause excess mortality. Our investigation uncovers distinct peaks in excess mortality, notably among individuals aged 80 years and older, revealing a strong positive correlation with excess temperatures (ET) during the summer of 2022 in Italy. Furthermore, we identify a notable role played by COVID-19 hospitalizations, exhibiting regional disparities, particularly during the winter months. Leveraging functional data regression, we offer robust and coherent insights into the excess mortality trends observed in Italy throughout 2022.

Transition‐Metal‐Mediated Fluoroalkylation of Carbon Electrophiles through Cross‐Electrophile Couplings

Comprehensive SummaryOrganofluorine compounds have attracted substantial interest in life and materials sciences due to the unique properties of fluorine atom(s) that often change the physicochemical and biological properties of organic molecules. Transition‐metal‐mediated cross‐electrophile coupling between carbon electrophiles and fluoroalkyl electrophiles has emerged as a straightforward and efficient route for the synthesis of a wide range of fluoroalkylated compounds because of its synthetic convenience without the tedious synthesis of organometallic reagents. Moreover, alkenes or alkynes‐involved three‐component cross‐electrophile couplings provide rapid and effective access to carbonfunctionalized fluoroalkylated alkanes and alkenes. Herein, we comprehensively summarize the transition‐metal‐mediated reductive fluoroalkylation of diverse carbon electrophiles through a historical perspective, including trifluoromethylation, difluoroalkylation, monofluoroalkylation, and so on. Different transition metals (Cu, Ni, etc.) and strategies are discussed, in which nickel‐catalyzed reductive fluoroalkylation reactions represent an attractive and efficient synthetic route to site‐selectively access organofluorine compounds. Key ScientistsAs early as 1965, McLoughlin and Thrower finished the first stoichiometric copper‐mediated fluoroalkylation of aromatic iodides with fluoroalkyl iodides. However, excess aromatic iodides and elevated temperature were used for this method. In 1969, Kobayashi and Kumadaki reported studies on the copper‐mediated trifluoromethylation of aromatic halides with excess trifluoromethyl iodide. After more than four decades, the Zhang group developed a nickel‐catalyzed β‐fluorinated alkylation of (hetero)aryl iodides with fluoroalkylated secondary alkyl bromides in 2015, and a nickel‐catalyzed difluoromethylation of (hetero)aryl chlorides with chlorodifluoromethane ClCF2H in 2017. The Zhang group also developed enantioselective nickel‐catalyzed reductive alkyl‐arylation of 3,3,3‐trifluoropropene with (hetero)aryl and tertiary alkyl iodides. In 2018, the MacMillan group developed a novel copper/photoredox dual catalytic system for the trifluoromethylation of aryl bromides or alkyl bromides with (S)‐(trifluoromethyl) dimesitylsulfonium triflate in the presence of tris‐(trimethylsilyl) silanol. They also developed a nickel/photoredox catalyzed difluoromethylation of aryl bromides in the presence of silane. During this time, the Wang group reported a nickel‐catalyzed monofluoroalkylation of aryl halides with monofluoroalkyl halides. From 2021 to 2023, the same group further developed a series of enantioselective nickel‐catalyzed trifluoroalkylation of aryl, alkenyl, and acyl halides. Moreover, nonfluorinated alkenes or alkynes could also be used in three‐component cross‐electrophile couplings. In 2018, the Chu group reported a nickel‐catalyzed fluoroalkyl‐acylation of alkenes with acyl chlorides and fluoroalkyl iodides. Later, they developed a nickel‐catalyzed enantioselective fluoroalkyl‐arylation of unactivated alkenes tethering with a pendant chelating group. In 2019, the Chaładaj group reported a palladium‐catalyzed reductive perfluoroalkyl‐arylation of alkynes with perfluoroalkyl and aryl iodides.

Assessment of physical factors of the educational environment in schools of the Chelyabinsk region and their influence on students’ adaptation

Introduction. The health of children and adolescents is a criterion of their body’s relationship with the environment and is formed under the influence of a complex set of social, biological and environmental factors. Educational organizations are the only system of public education that covers the entire child and adolescent population of the country for a long period of time. Physical factors of the intra-school environment affect the physiological processes of the body of schoolchildren and ensure adaptation to physical exertion. The purpose of the study: to study and evaluate the physical factors of the educational environment in schools of the Chelyabinsk region in the dynamics of five years and the adaptive potential of students. Materials and methods. Statistical, mathematical and instrumental research methods are used in the work. The conditions of physical education classes in 10 schools in the cities of the Chelyabinsk region from 2018–2022 were studied and an assessment of physical performance was carried out in 102 students of grades 8–9. It was found that the largest share was accounted for by objects classified as medium risk and moderate risk in 2020–82.8 %. Results. The proportion of educational institutions that do not meet sanitary and hygienic standards in terms of artificial illumination and electromagnetic studies remained high and amounted to 14.2 % and 8.9%, respectively, excess air temperature was detected in 20 % of the studied schools. In 60 % of the schools studied, outdoor sports grounds have not been repaired since they were put into operation. Conclusion. 26.7 % of respondents showed satisfactory adaptation to physical exertion, 73.3 % (2.8 times more) of respondents noted the strain of adaptation mechanisms. The number of students with overweight and revealed stress of adaptation mechanisms was 66.7 %, and with a lack of body weight, this figure was 2.1 times less and amounted to 28.5 %. A third (33.3 %) of overweight respondents showed satisfactory adaptation, while underweight students showed 2.2 times higher (71.5 %).

Impact of hot and cold nights on pneumonia hospitalisations in children under five years: Evidence from low-, middle-, and high-income countries

BackgroundStudies have shown that abnormal temperature at night is a risk factor for respiratory health. However, there is limited evidence on the impact of hot and cold nights on cause-specific diseases such as pneumonia, which is a leading cause of morbidity and mortality in children. MethodsWe collected daily data on pneumonia hospitalisations in children under five years from 2011 to 2017 in three low-, middle- and high-income countries (Bangladesh, China, and Australia). The intensity of hot and cold nights was measured by excess temperature. A space–time-stratified case-crossover analysis was used to estimate the association between hot and cold nights and childhood pneumonia hospitalisations. We further estimated the fraction of childhood pneumonia hospitalisations attributable to hot and cold nights. ResultsBoth hot and cold nights were associated with an increased risk of hospitalisations for childhood pneumonia in low-, middle-, and high-income countries, with a greater disease burden from hot nights. Specifically, the fraction of childhood pneumonia attributable to hot nights was the largest in Australia [21.2%, 95% confidence interval (CI): 11.8%-28.1%], followed by Bangladesh (15.2%, 95% CI: 4.1%–23.8%) and China (2.7%, 95% CI: 0.4%-4.7%). Additionally, the fraction of childhood pneumonia attributable to cold nights was 1.3% (95% CI: 0.4%-2.0%) in Bangladesh and 0.4% (95% CI: 0.1%-0.7%) in China. ConclusionThis multi-country study suggests that hot and cold nights are not only associated with a higher risk of pneumonia hospitalisations in children but also responsible for substantial fraction of hospitalisations, with a greater impact from hot nights.

Is the rate of extremely climate-intensifying rainfall for Bangkok severely propagating into flooding?

ABSTRACT The present paper assesses whether the extremely climate-intensifying rate (i.e., 14%/°C) for maximum rainfall in Bangkok is severely propagating into flooding. The impact evaluation involves the development of a flooding assessment method for a drainage system (DS) representative of the capital and the application of the developed procedure to assess the interested effect of the DS on its flooding. Considering the DS of Thammasat University (DS-TU) as the typical DS for the city, the popular storm water management model (SWMM) is then used for developing the dynamic simulation method against the most critical flooding condition of the DS-TU. Applying this SWMM for impact assessment of the intense rainfall rate has indicated that the rising temperature in excess of 2 °C would cause the gradient to severely propagate into the flooding because of the rapid increase in its associated peak, volume and duration properties. The propagated flooding has been shown to be further escalated, as a result of the clogging in the DS-TU. The clogging height that exceeded the 30% threshold of the full openings would intensify the volume and duration properties increasingly.

Adding branched fin angle as degree-of-freedom improves performance of a T-Y-shaped fin

A variable-angle T-Y-shaped fin model is built herein. Constructal design of the variable-angle T-Y-shaped fin model is studied by introducing branched fin angle as an additional design variable. Firstly, with the goal of minimizing maximum dimensionless excess temperature (MDET), the branched fin angle of T-Y-shaped fin model is optimized. Secondly, heat transfer performance of T-Y-shaped fin is further optimized with 2-degree-of-freedom (DOF) and 3-DOF optimizations including branched fin angle. According to the results, in the 1-DOF optimization, when the branched fin angle reaches 17.2°, the MDET reaches the minimum at the value of 30.78, which is 19.32 % lower than that when the branched fin angle is 90°. Furthermore, the MDET of the T-Y-shaped fin under 3-DOF optimization is 27.20, which is 28.70 % lower than the result when the branched fin angle is 90°, and 11.63 % lower than that of the 1-DOF optimization. It is necessary to add the branched fin angle as an optimization variable. Moreover, the optimization effect of 2-DOF is significant, while that of 3-DOF is not obvious. The outcomes obtained from this study may serve as theoretical counsels for heat dissipation in the designs of fins for various thermal systems.

The risk of hospitalization associated with hot nights and excess nighttime heat in a subtropical metropolis: a time-series study in Hong Kong, 2000–2019

Recent studies showed increased mortality risks after hot nights, but their effect on hospitalizations, especially in vulnerable populations, remains under-studied. Daily hospitalization, meteorological (including hourly), and air pollution data were collected for the hot seasons (May-October) of 2000-19 in Hong Kong. We derived three hot-night metrics: HNday28 °C, daily minimum temperature ≥28°C, the governmental definition of hot nights; HNe, hot night excess calculated by summing heat excess of hourly temperatures above 28°C at night; and HNday90th, hot nights classified using the 90th percentile HNe (17.7°C⋅h) as a cutoff. We fitted time-series regression with distributed lag nonlinear models to examine the associations of hot-night metrics with various hospitalizations. During the 3680 study days, 5,002,114 non-cancer non-external (NCNE) hospitalizations were recorded. Half (1874) of the days experienced excess nighttime heat (HNe>0) with a mean (SD) of 8.0 (6.8) °C⋅h; 499 and 187 hot nights were identified by HNday28 °C and HNday90th, respectively. Extreme HNe (99th percentile vs 0°C⋅h) was significantly associated with increased NCNE hospitalizations over lag 0-4 days by 3.1% [95% confidence interval: 1.5%, 4.8%] overall, with enhanced effects in elderly (5.3% [3.2%, 7.4%]), low-SES individuals (5.3% [2.8%, 8.0%]), and circulatory admissions (3.4% [0.2%, 6.8%]). HNday90th, reflecting extreme HNe, better identified hazardous hot nights than the official HNday28 °C. Excessive nighttime heat is significantly associated with increased hospitalizations, particularly affecting the elderly and socioeconomically disadvantaged individuals. Nighttime heat intensity should be incorporated in defining hot nights with public health relevance. British Heart Foundation.