Increase In Ambient Temperature Research Articles

Quality improvement of lime fruit (Citrus aurantifolia) between packaged and unpackaged conditions combined with different storage temperatures

Background: The use of limes is increasingly widespread worldwide, both as fresh fruit for consumption and for making juice or other drinks. Lime is also used in making jams and candies. The essential oil obtained from the skin is widely used in the pharmaceutical and cosmetic industries for medicines, perfumes, soaps, body lotions, and detergents. However, during fruit storage, the respiration and metabolic activity in lime fruits is directly related to the increase in ambient temperature, which makes the fruit dry out. Improving the shelf life of lime against post-harvest stress while maintaining the sensory and nutritional qualities of fresh produce can be achieved through low-temperature storage and the use of packaging. This study aims to improve the quality of lime by knowing the difference between the provision of packaging and not-given packaging combined with different storage temperatures. Method: The experimental design used a single-factor completely randomized design with storage type treatment, which includes room temperature without packaging (control), room temperature with packaging, low temperature without packaging, and low temperature with packaging. Observations of non-destructive characteristics include weight loss, respiration rate, and fruit peel color. Observations of destructive characteristics include juice content, fruit peel softness, Soluble Solid Contents (SSC), Total Acidity (TA), SSC/TA ratio, and ascorbic acid content. Finding: Low temperature treatment without packaging provides the best results in delaying weight loss, respiration rate, and SSC/TA ratio. The control treatment provided the best results for peel softness, juice content, and ascorbic acid. Conclusion: Low temperature treatment without packaging is recommended for the storage of lime fruit to extend its shelf life. Novelty/Originality of this Study: This study examines the combined effects of low temperature and newspaper packaging on extending the shelf life of lime fruits, addressing a significant gap in postharvest storage research for non-climacteric fruits such as lime.

Behavioral strategy of adaptation of <i>Polypterus senegalus</i>(Polypteridae) with an increase in ambient temperature

This paper investigates the effect of temperature increase on the behaviour of Polypterus under laboratory experimental conditions. To investigate the effect of a change in temperature regime, analysis of video recordings of animal behaviour over eight hours under acclimation conditions and under a constant temperature increase is used. The temperature increase occurred at a rate of 1,125°C/hour. The movement trajectories of the animals under normal conditions and under a sudden increase in ambient temperature are described. The paper presents results on the speed and activity of the fish movements and the number of acts of air entrapment by polypterus from the water surface. The studies show that the increase in temperature leads to an increase in the variability of the animals’ movement trajectories. A steady increase in temperature leads to an increase in the speed and activity of the animals’ movements. As the temperature regime changes, there is an increase in the number of acts of air capture from the water surface. The largest jump in activity change is observed in the second and third hours of temperature increase. The obtained material can serve as a basis for the development of ideas about the behavioural adaptation of bony fishes to the increase in ambient temperature. The observed regularities in the responses to temperature changes will make it possible to improve the technology of polypterus cultivation.

Experimental investigation of a transcritical CO2 refrigeration system incorporating rotary gas pressure exchanger and low lift ejectors

Natural refrigerants like CO2 are playing a significant role in making refrigeration and heat pump systems climate-friendly by slowly phasing out the high global warming refrigerants like hydrofluorocarbons (HFCs). However, the efficiency of a transcritical CO2 refrigeration system declines significantly when the ambient temperature increases, primarily attributed to the high-pressure lift and the losses incurred during expansion. To remedy this issue, this paper presents a novel rotary gas pressure exchanger (PXG) device, which simultaneously achieves high differential pressure expansion work recovery and the “free compression” of the portion of the flash gas in a compact, rotary machine. For this, a PXG device is designed, fabricated, and tested to achieve free compression of CO2 over the entire differential pressure of approximately 70 bar between a receiver and a gas cooler. This is one of the highest free-pressure lift provided by any device to date in CO2 refrigeration. However, there is a small pressure loss of approximately 1–2 bar in the system due to viscous and inertia losses in the piping and in the PXG itself, which needs to be overcome by an external booster device. Results on a baseline PXG integrated system with two low lift booster compressors are presented, which show up to 60 bar free pressure lift and up to 18.2 % COP improvement provided by PXG. Additionally, key performance characteristics of the PXG, like the expansion work recovery, the mass boost ratio, direct fluid-to-fluid contact, and no pass-through operation are experimentally quantified. This work also presents a novel method to integrate two low lift ejectors with PXG to eliminate the need for separate low lift compressors. The low lift ejectors are designed, fabricated, and tested in-house, followed by their integration with the PXG device. A new type of transcritical CO2 refrigeration system is designed to integrate these low lift ejectors with PXG, and experiments are conducted at various evaporator thermal duties and gas cooler exit temperatures, simulating varying ambient temperature conditions. A novel control system to control the gas cooler pressure to optimal thermodynamic levels using PXG rotational speed is demonstrated experimentally. Further, automated control of high-pressure low lift ejector mass flow using an in-built needle design has been successfully demonstrated to optimise PXG mass boost performance. The LP low lift ejector achieved a successful pressure lift of 3.8 bar, and the HP low lift ejector showed a lift of 5.7 bar on the top of 42 bar free pressure lift provided by PXG for up to 5.8 kg/min mass flow delivered by free PXG compression. The results from this study demonstrate that the PXG device provides a significant energy efficiency improvement to the transcritical CO2 refrigeration system, and the novel low lift ejectors, when integrated with PXG, provide a successful method to maximise PXG’s thermodynamic potential.

Isentropic and exergy analyses of marine steam turbine segments at several loads

This research presents isentropic and exergy analyses of marine steam turbine segments at three loads. Turbine segment is a part of any cylinder which is placed between the steam entrance to the cylinder and first steam extraction, between steam extractions and finally between last steam extraction and steam exit from the cylinder. Division of each cylinder to the segments allows insight into the various cylinder parts operation and an observation is the cylinder properly balanced. The analyzed marine steam turbine is composed of two cylinders – High Pressure Cylinder (HPC) and Low Pressure Cylinder (LPC), while each cylinder has two segments. The dominant part of real mechanical power produced in HPC is actually produced in the first HPC part (segment 1), while in LPC, the dominant part of real mechanical power is produced in the last LPC part (segment 4). Segments 1 and 3 have the highest improvement potential (inlet segments of both HPC and LPC) due to the highest isentropic losses and exergy destructions. HPC is much better balanced cylinder because along with isentropic, also exergy efficiencies between its segments (segment 1 and segment 2) at all loads differ lower than 7%, while the same cannot be stated for the LPC which exergy efficiencies between segments (segment 3 and segment 4) at all loads differ more than 20%. Very low isentropic and exergy efficiencies of the segment 3, at all observed loads, indicate that this turbine segment is highly problematic and at least some of the turbine stages mounted in this segment have difficulties in operation or potential malfunction. In addition, segment 3 is also the highest influenced by the ambient temperature change in comparison to other segments. The ambient temperature increase from 5 °C up to 45 °C can decrease segment exergy efficiency between 1.31% and 3.17%, if all the segments and all loads of the analyzed marine steam turbine are observed.

Effect of non-optimal ambient temperature on preterm birth stratified by social positioning in Nepal: A space–time-stratified case-crossover study

BackgroundThe ongoing increase in the mean global temperature due to human induced climate change, indicates that women and infants will have higher exposure to heat events leading to adverse outcomes. The study investigates the effect of non-optimal ambient temperature on the risk of preterm birth stratified by social position in Nepal. MethodThis is a space–time-stratified case-crossover design, based on hospital-registered perinatal data between 2017 and 2021 (n = 47,807). A daily count of pregnant women residing in seven heat-prone districts was extracted together with their social status (ethnicity), obstetric complication and gestation of birth. The daily count of events was matched with the daily ambient temperature of their residence using the NOAA spatial temperature recording. Ambient temperature exposure was analysed using conditional Poisson regression and distributed lag non-linear models. FindingsIn the general population, with exposure to ambient temperature at the 75th centile (28 °C) the cumulative risk of preterm birth over 28 days was 1·29 times higher (RR, 1·29; 95% CI; 1·09, 1·54) than at median temperature (24.1 °C), and even higher among the socially disadvantaged population. Cumulative risk of preterm birth to cold ambient temperature at the 1st centile was high but not significant. Exposure to ambient temperature at the 90th centile (32·5 °C) had the highest cumulative risk of preterm birth for pregnant women from socially disadvantaged populations (RR 1·81; 95% CI; 1·28, 2·55). The delayed effect after exposure to temperatures above the 75th percentile was more prolonged in the disadvantaged than the advantaged social group. ConclusionAlthough exposure to cold with certain effect on preterm births, heat (increase in ambient temperature) carries a risk of preterm birth in Nepal, and is more profound among socially disadvantaged populations.

Diffusion characteristics of indoor pollutants from incense sticks combustion in Tibetan Plateau buildings: An experimental study

Incense burning, a common practice among ethnic Tibetans in Qinghai-Tibet Plateau of China, generates pollutants that can impact indoor air quality and, subsequently, human health. In this paper, we investigate the diffusion characteristics of four prevalent pollutants emitted during the burning of local Tibetan incense under low-pressure conditions specific to the plateau region. The diffusion behavior of these incense burning pollutants deviates from that observed under standard atmospheric pressure due to the unique conditions prevailing at high altitudes. The research results reveal that the primary pollutants released during Tibetan incense combustion are carbon dioxide, inhalable PM2.5, and PM10. Furthermore, ambient temperature exerts a substantial influence on the concentration of pollutants emitted during incense burning. A 6 °C increase in ambient temperature results in a 1.17-fold rise in the combustion rate. Consequently, higher temperatures correspond to larger diffusion coefficients, increased gas diffusion rates, and elevated pollutant concentrations at equivalent combustion times. Simultaneously, the low oxygen content characteristic of plateau regions has a notable impact on the diffusion rate of gaseous pollutants. This study of pollutant concentration and diffusion characteristics during incense burning offers valuable insights for determining the minimum ventilation rate in plateau areas.

Simulation Study of Thermal Performance on the Inner and Outer Surfaces of Semi-Transparent Photovoltaic (STPV) Glass with Different Transparency

This paper used the experimentally verified one-dimensional steady-state heat transfer numerical model of the semi-transparent photovoltaic (STPV) glass to simulate the influence of wind speed, ambient temperature and air gap thickness on the surface temperature of PV modules, and analyzed the thermal performance of the inner and outer surfaces of STPV glazing with different transparency. Results shows that for every 1m/s increase in wind speed, the outer surface temperatures of SL-STPV glass with transparency of 10%, DL-STPV glass with transparency of 20% and 40% decreased by 3 °C, 3.02 °C and 2.22 °C, respectively. For every 10 °C increase in ambient temperature, the outer surface temperatures of SL-STPV glass with transparency of 10%, DL-STPV glass with transparency of 20% and 40% increase by 8.45 °C, 7.6 °C, and 7.79 °C, respectively. For the DL-STPV glass with transparency of 20% and 40%, for every 2 mm increase in the thickness of the air gap, the outer surface temperature increases by 0.13 °C and 0.12 °C, respectively. The heat transfer between the inner surface of the glass and the indoor environment increases the heat gain through the glass into the room in summer, which will lead to an increase in refrigeration energy consumption. However, in winter, the heat exchange between the inner surface and the in-door air to heat the indoor air reduces the heating energy consumption to a certain extent, and achieves the effect of building energy conservation to a certain extent.

Spatial characterisation and drivers of catch and effort in highly specialised recreational pelagic fisheries

Large pelagic finfish are highly mobile, distributed across broad geographical scales, and often targeted by both commercial and recreational sectors. Fishing effort in these fisheries is variable due to seasonal patterns in fish behaviour and accessibility of fishing locations. Similarly, fisher behaviour and access are likely to differ within the recreational sector, between private boat-based fishing and charter (or for hire) fishing. Here, we compare spatio-temporal patterns in catch per unit effort (CPUE), effort (boat days) and catch (total catch per fishing party) for private boat-based and charter fishing, and identify environmental variables that may influence those patterns, for two pelagic species (the tropical narrow-barred Spanish mackerel and temperate Samson fish) in Western Australia. Spatial and temporal patterns of CPUE were investigated using geostatistical indices, such as the global and local index of collocation which compares the spatial distribution of CPUE locations across years and CPUE values at common locations respectively, and the centre of gravity which calculates the mean fishing location weighted by CPUE, along with the influence of environmental variables (including rainfall and sea surface temperature) on catch using generalised additive models (GAMs). The global index of collocation showed consistency in spatial distribution of CPUE and effort between private boat-based and charter fishing for both species. In contrast, the local index of collocation showed differences in the ranges of CPUE and effort within common locations. Private boat-based fishing often occurred close to the coast and adjacent to population centres, while charter fishing occurred further offshore. Spatial shifts over time were more prominent for Spanish mackerel with an overall northerly shift. For private boat-based fishing, higher catches of Spanish mackerel were associated with higher rainfall, along with an increase in ambient air temperature. For charter fishing, higher catches of Spanish mackerel occurred with ambient air temperatures of around 30 degrees Celsius and a decrease in rainfall, where high catches of Samson fish were associated with a decrease in sea surface temperatures and austral winter months. This study highlights changes in the distributions of pelagic species over time and the potential to incorporate spatio-temporal monitoring of recreational harvest into fisheries management.

Influence of ambient temperature on multidimensional signal dynamics and safety performance in lithium-ion batteries during overcharging process

Ambient temperature significantly influences the safety performance of lithium-ion batteries (LIBs), particularly their thermal runaway (TR) behaviors. Yet, the complexities of multidimensional signal dynamics in overcharged LIBs under different ambient temperatures are not well understood. In this study, we performed comprehensive overcharging abuse tests under cold (-10 °C and 0 °C), normal (20 °C), and high ambient temperatures (60 °C), to investigate the evolution of multidimensional signals of expansion force, gas concentration, surface temperature, and voltage. Results show that TR events are not triggered at ambient temperatures of −10 °C and 0 °C, with the maximum temperatures and corresponding rise rate reaching only 125 °C and 0.5 °C/s, respectively. In contrast, for batteries undergoing TR, the maximum temperatures and rates of temperature increase peaked at 410.3 °C and 20.6 °C/s, respectively. The ambient temperature has a minimal impact on the venting force of the battery, which varies from approximately 9500 N to 10000 N, primarily driven by an increase in internal gas pressure during overcharging—a factor relatively unaffected by temperature changes. After safety valve activation during overcharging, Hydrogen (H2) is consistently the first gas detected immediately across all ambient temperature scenarios. Additionally, an increase in ambient temperature results in earlier detection of abnormal expansion and venting behaviors, characterized by lower venting voltages and higher venting temperatures. This study contributes to a deeper understanding of battery failure mechanisms under various ambient temperatures and informs the development of early safety warning strategies for LIBs during the charging process.

Comparing Influence of Thermal Effects in Experimental Models - Thermotherapy in Medical Rehabilitation

Introduction: The subject of thermometry and impact of thermal effect on the human body is still a topic known and discussed in medical care. One of the basic methods in clinical diagnosis is the measurement of body temperature. In biological tissues, there are two main types of reactions caused by optical radiation: photochemical and thermal. The effects of radiation exposure depend on its properties and physical parameters, including the amount of absorbed dose and the duration of exposure. In the case of thermotherapy as a therapeutic method, the appropriate choice of radiation type and the selection of physical parameters is a necessary condition for obtaining desired, beneficial therapeutic effects. The aim of the study is to investigate the thermal effect of non-ionizing radiation: infrared (IR), ultraviolet (UV) and electromagnetic field (EMF) induced in short-wave diathermy (MD), measured with classical thermometers and a thermal imaging camera. The thermal effect, as a result of overheating with three different factors: IR, UV, MD; and under the same conditions, is studied. The variation in temperature distribution in different phantoms is evaluated in order to delve into the subject of thermal effect regarding each radiation separately and to consider its suitability for medical diagnosis and therapy.Material and methods: The thermal effect study was carried out on two phantoms. The first phantom F1 - a wooden cuboid (27.0 x 7.0 x 7.5cm) with five holes drilled at 5-cm intervals, into which thermometers were inserted (depth 5 cm). The second phantom - F2 was a biological tissue, the lower part of pork ham cut off along with the bone with fat covering and skin. Phantoms F1 and F2 were treated with an infrared heater (P1), a lamp emitting ultraviolet radiation (P2) and short-wave diathermy (P3); C and irradiation - 20 minutes, temperature measurements at intervals of 5 minutes, i.e. 5, 10, 15 and 20 minutes for the examined factors. During the experiment, temperature measurements were periodically made with the IR Thermal Radiometric Camera MobIR M3. For obtaining reliability of the measurements, the whole trial was repeated 10 times. Before the thermograms were made, two-hour intervals were applied between successive measurements, maintaining a constant ambient temperature of 23C.Results: With regard to UV radiation, there was an increase in the average temperature among the thermometers. This was particularly noticeable in the first thermometer with a 1.9% increase (up to 25.110.29C) above the ambient temperature (24.650.34C) after 15 minutes of measurements. After 20 minutes, the average temperature increase in thermometer 1 was 2.2% (up to 25.180.23C). A temperature increase in subsequent thermometers may be related to thermal conductivity and an increase of ambient temperature. In turn, for IR, an average 1.7% (to 25.160.87C) temperature increase of all thermometers was observed at 15 minutes and at 20 minutes, by 2.9% (to 25.481.35C) compared to baseline temperature (24.750.47\C). Comparing the average temperature of thermometer 1 with the ambient temperature (24.750.49C), the highest increase of 12.8% (to 27.930.69C) was noted after 20 minutes of measurements. In diathermy, after 10 minutes, an increase in the average temperature in thermometer 1 was observed by 2.8% (to 25.690.46C) above the ambient temperature. The highest increase in average temperature was recorded in thermometers 1 and 5 in the 20thminute of measurements.Conclusions: All of the applied methods caused temperature increases in the used phantoms. The temperature distribution in the wooden phantom corresponds to that in the biological tissue for the interaction of infrared radiation (IR) and short-wave diathermy (MD), which was confirmed by thermovision. The increase in the internal temperature of the superheated biological structure corresponds to the increase in the distribution of the phantom’s internal temperature.

Association of Psychiatric Emergency Visits and Warm Ambient Temperature during Pregnancy: A Time-Stratified Case-Crossover Study.

Acute exposure to high ambient temperature and heat waves during the warm season has been linked with psychiatric disorders. Emerging research has shown that pregnant people, due to physiological and psychological changes, may be more sensitive to extreme heat, and acute exposure has been linked to increased risk of pregnancy complications; however, few studies have examined psychiatric complications. Our objective was to examine the association between acute exposure to warm ambient temperatures and emergency department (ED) visits for mental disorders during pregnancy. A time-stratified case-crossover design with conditional logistic regression was performed on psychiatric ED visits for pregnant patients in North Carolina, from May to September 2016 to 2019. Daily average ambient temperature was the main exposure and was linked to daily visits by maternal zip code of residence for prenatal mood and anxiety disorders (PMAD), severe mental illness (SMI), mental disorder of pregnancy (MDP), suicidal thoughts (SUIC), and any psychiatric disorder (Any). Effect modification by trimester, residential segregation, economic segregation, urbanicity, and availability of greenspace was also investigated. Each increase in same-day exposure to warm ambient temperature on case days was associated with an increase in incidence rate ratio (IRR) for any psychiatric disorder [IRR = 1.07; 95% confidence interval (CI): 1.01, 1.14] including anxiety (IRR = 1.14; 95% CI: 1.00, 1.30), bipolar disorder (IRR = 1.28; 95% CI: 0.98, 1.67), and suicidal thoughts (IRR = 1.28; 95% CI: 1.00, 1.65) compared to control days. In general, the associations were strongest for warm season temperatures on the same day of exposure or for temperatures averaged over the 3 or 6 d preceding the ED visit. The greatest risk of an incident ED admission for PMAD (RR = 1.20; 95% CI: 1.04, 1.39), particularly for anxiety (RR = 1.30; 95% CI: 1.07, 1.59), and any psychiatric disorder (RR = 1.17; 95% CI: 1.07, 1.28) occurred following cumulative exposure to hot temperatures the week before admission. Higher psychiatric burden from temperature was observed in urban areas and on extreme heat days. For this pregnant population in the southeastern United States, short-term exposure to high ambient temperatures during the warm season was associated with a greater risk of ED visits for an array of psychiatric disorders. Findings show that climate-related increases in ambient temperature may contribute to psychiatric morbidity in pregnant people. https://doi.org/10.1289/EHP13293.

Microbial transformation mechanisms of particulate organic carbon to mineral-associated organic carbon at the chemical molecular level: Highlighting the effects of ambient temperature and soil moisture

Soil dissolved organic matter (DOM), an important component of active soil organic carbon (C), plays a crucial role in controlling C transformation. However, the role of DOM in mediating the conversion of particulate organic C (POC) into mineral-associated organic C (MAOC) at the molecular level remains unclear. In this study, the microbial conversion of POC to MAOC at the molecular level was investigated at different ambient temperatures and soil moisture levels. An increase in ambient temperature led to the conversion of POC to labile C, whereas MAOC increased with soil moisture. CHO, CHNO, and CHOS increased with soil moisture and temperature. The highest temperature (35 °C) promoted conversion of lignin/cram (carboxyl-rich alicyclic molecules)-like molecules into aromatic components with the highest intragroup transformation of DOM (74%). The highest soil moisture (60%) favoured the conversion of refractory substances into aliphatic/peptide and lipid components with the highest intergroup transformation (28%). Compared to fungi, bacteria were the main driving force for DOM transformation. Therefore, changes in ambient temperature and soil moisture control the microbial formation and transformation of different C fractions (i.e. POC and MAOC) via DOM differently at the molecular level.

Study on performance of direct-expansion heat pump water heater integrated uninsulated micro-channel PV/T solar collector

In this paper, a direct-expansion heat pump water heater system integrated uninsulated micro-channel PV/T solar collector (UMC-PVT-SC) is proposed. This system can realize storage for both thermal energy and electricity, ensuring the supply of domestic hot water. The theoretical models of micro-channel PV/T solar collector, hot water storage tank, compressor and electronic expansion valve are established to investigate the performance of the micro-channel PV/T heat pump water heater system. R134a is used as refrigerant. The system performance is numerically simulated using MATLAB for different solar radiation intensity, ambient temperature and wind speed. The results show that solar radiation intensity has the largest influence on the system performance, followed by ambient temperature and wind speed. The coefficient of performance of the heat pump (COPHP) and the overall coefficient of performance (COPpvt) of the integrated system increase while the required operating time reduces, as solar radiation intensity and ambient temperature increase. The uninsulated micro-channel PV/T solar collector (evaporator) can absorb thermal energy from both ambient air and solar radiation and therefore achieve high COPHP, electric efficiency and COPpvt. Even under cold weather conditions, the proposed solar collector and heat pump heater demonstrate high efficiencies, heating and power generation capacities. When ambient temperature is −18.6 °C and solar irradiance is 322 W/m2, the collector efficiency and electric efficiency of UMC-PVT-SC are still at 0.718 and 0.244, respectively, and the COPHP and COPpvt of the heat pump heater are 3.5, 5.63, respectively. The present work is of potential value for delivering net zero.

Effect of increasing ambient temperature on physiological changes, oxidative stress, nitric oxide, total antioxidant power, and mitochondrial activity of Nile tilapia (Oreochromis niloticus Linn.)

The objective of this study was to investigate the effect of high ambient temperature on physiological changes of live Nile tilapia (Oreochromis niloticus Linn.) and biochemical parameters in Nile tilapia blood cells. Live Nile tilapia and Nile tilapia blood cells were maintained at temperature ranges from 24 to 34 °C and 24–38 °C, respectively. Then, physiological parameters (body temperature, body color score, pulse rate, ventilation rate, oxygen saturation) of the live Nile tilapia and biochemical parameters (total antioxidant power, hydrogen peroxide, malondialdehyde, nitric oxide, and mitochondrial activity) of the Nile tilapia blood cells were measured for every 2 °C increase. It was found that when the ambient temperature increases, body temperature of live Nile tilapia continually increased. Total antioxidant power and hydrogen peroxide, pulse rate, body color score, malondialdehyde, ventilation rate and mitochondrial activity commenced to increase at 26, 28, 30, 32, 34 °C (P < 0.05), respectively. Blood oxygen saturation decreased at 32 °C (P < 0.05). The response of nitric oxide of Nile tilapia blood cells responded to increased temperature in two phases. In the first phase, nitric oxide decreased at 28–32 °C (P < 0.05), then increased and decreased again at a temperature of 38 °C (P < 0.05). These phenomena indicated that when the live Nile tilapias and the Nile tilapia blood cells were exposed to high ambient temperature, they were under heat stress and oxidative stress. In addition, physiological responses in the live Nile tilapia and biochemical changes in their blood cells when exposed to high ambient temperature occurred in a consistent manner when the temperature continually increased.

Anthropogenic heat from buildings in Los Angeles County: A simulation framework and assessment

Anthropogenic heat (AH), i.e., waste heat from buildings to the ambient environment, increases urban air temperature and contributes to the urban heat island effect, which leads to more air-conditioning energy use and higher associated waste heat during summer, forming a positive feedback loop. This study used a bottom-up simulation approach to develop a dataset of the annual hourly AH profiles for 1.7 million buildings in Los Angeles (LA) County for the year 2018 aggregated at three spatial resolutions: 450 m, 12 km, and the census tract. Building AH exhibits strong seasonal and diurnal patterns, as well as large spatial variations across the urban areas. Building AH peaks in May and reaches a maximum of 878 W/m2 within one of several AH hotspots in the region. Among the three major AH components (surface convection, heat rejection from HVAC systems, and zonal air exchange), the surface convection component is the largest, accounting for 78% of the total building AH across LA County. Higher AH is attributed to large building density, a high percentage of industrial buildings, and older building stock. While AH peaks during the day, the resulting ambient temperature increases are much larger during the night. During the July 2018 heatwave in LA County, building AH (excluding the surface component) leads to a daily maximum ambient temperature increase of up to 0.6 °C and a daily minimum ambient temperature increase of up to 2.9 °C. It is recommended that reducing summer building AH should be considered by policy makers in developing mitigation measures for cities to transition to clean energy while improving heat resilience.

Heat waves and pediatric emergency department febrile-related visits

BackgroundIn recent decades, we have observed an increase in ambient temperature due to the effects of climate change. ObjectiveIn this study, we aimed to determine whether there is a correlation between environmental temperature and urgent consultations of pediatric patients related to febrile processes. Research design and methodWe conducted an observational, retrospective, single-center study in the pediatric ED of the Hospital Universitario La Paz, Madrid, Spain. We analyzed visits to the ED for febrile processes during the last heat waves in Madrid. ResultsBetween 2018 and 2022, seven heat waves were recorded in Madrid. A total of 3967 patients with fever as the main reason for consultation attended during this period. In two of the seven heat waves analyzed, febrile-related visits were higher during the heat alert. The first occurred between 6/11/2022 and 6/16/2022, with 345 febrile-related ED visits, 25.4% more than the previous days and 19.7% more than the following days. During this heat wave, we observed a positive correlation between the maximum temperature recorded and the number of visits to the ED for febrile processes (Rs=0.552; p = 0.018). During the heat wave between 09/07/2022 and 17/07/2022, 362 febrile-related ED visits were 3.1% more than the previous days and 24.9% more than the following days. ConclusionDuring recent heat waves in our city, we registered an increase in febrile-related visits compared with non-heat alert periods.

Optical, electrical, and thermal performance of low-concentrating photovoltaic/thermal system using microencapsulated phase change material suspension as a coolant

Concentrated photovoltaic/thermal (C-PV/T) systems exhibit superior output compared to common PV/T collectors. To address potential issues caused by excessive concentration of conventional parabolic concentrators and enhance the electro-thermal co-generation capability, this work proposes a low-concentrating PV/T (LC-PV/T) system that integrates two improved concentrator designs and a coolant of microencapsulated phase change material suspension (MPCMS). A numerical model is established to investigate the effects of working conditions and meteorological conditions on the optical, electrical and thermal performances. The results indicate that the improved concentrator designs effectively prevent over-concentration of sunlight while maintaining a comparable concentration ratio (CR). The electrical output increases with an increase in mass fraction, inlet mass flow rate and solar irradiance, but decreases with an increase in ambient temperature and inlet temperature. Conversely, thermal output increases with an increase in all of these parameters except for the inlet temperature. This system can achieve 17 % electrical efficiency and 72 % thermal efficiency due to the high-efficiency solar cells, optimized concentrator design, and unique MPCMS coolant. The system can produce a maximum electrical power of 4.76 kW/m2 and a maximum thermal power of 19.53 kW/m2. Throughout the day, total electrical and thermal energies are approximately 4.1 kWh and 58.8 MJ.

Comparative Analysis of Current-Voltage Characteristics of Photovoltaic (PV) Systems in Selected Climatic Regions in Cross River State, Nigeria

This study investigated the effect of solar radiation’s intensity and ambient temperature on the current-voltage (I-V) characteristics of monocrystalline and polycrystalline photovoltaic (PV) systems in the generation of electricity in Calabar and Okuku, Cross River State, Nigeria. Appropriate measuring devices were employed to record daily readings of these parameters at the study locations, from July to August 2022. The data were collected and results graphically analyzed and calculated. The results indicate that current (Isc), voltage (Voc) as well as the maximum power (Pmax) of both module types increased positively with increase in solar radiation and ambient temperature. Results from collected and computed data also show average daily readings across the locations for solar radiation ranging between 271Wm-2 and 409Wm-2 and ambient temperature between 320C and 370C. The calculated Pmax ranges between 49W and 63W from the 130W solar modules used for the investigation. Another notable result is that the polycrystalline module exhibits higher Pmax than the monocrystalline module in both locations. In spite of the low solar radiation and ambient temperature obtained during this study period, which is considered the worst climatic period of the year (July and August), it is desirable and recommendable to employ solar modules as an alternative power generation in Calabar and Okuku, Cross River State, Nigeria.

Energy and exergy-based degree-hours in estimation of heat requirements for heating and cooling purposes

This study presents an innovative exergy-based methodology to revolutionize the assessment of heating and cooling energy utilization, transcending the limitations of traditional heating and cooling degree-hours (HDH and CDH) analyses. The study’s distinctiveness stems from its investigation into variations in HDH and CDH concerning critical parameters such as ambient temperature, solar-air temperature, solar absorptivity, surface emissivity, and total heat transfer coefficient. This fosters a profound comprehension of the thermodynamic performance of building heating and cooling systems, empowering decision-makers with the insights needed to optimize energy utilization effectively. As demonstrated through a case study conducted in Antalya, Turkey, this study uncovers significant findings. A mere 1 °C increase in ambient temperature results in an average 14 % surge in heating demand and an average 17 % decline in cooling demand, leading to a substantial 1000°-h discrepancy between heating and cooling requirements. Furthermore, we underscore the sensitivity of energy demand to temperature fluctuations, the substantial impact of design temperature on energy consumption, the notable influence of solar effects on environmental conditions, and the potential for optimization in parameters such as solar absorptivity, surface emissivity, and total heat transfer coefficient. These insights underscore the significance of exergy-based systems, offering heightened energy efficiency, swift adaptability to temperature changes, integration of renewable energy sources, and intelligent control features that contribute to sustainability and energy savings.

Climate Change and Stroke: A Topical Narrative Review.

The impacts of accumulating atmospheric greenhouse gases on the earth's climate are now well established. As a result, there have been increases in ambient temperatures and resultant higher frequency and duration of temperature extremes and other extreme weather events, which have been linked to a wide range of adverse health outcomes. This topical narrative review provides a summary of published evidence on the links between climate change and stroke. There is consistent evidence of associations between stroke incidence and mortality and increasing ambient temperature and air pollution. Associations have also been shown for changes in barometric pressure, wildfires, and desert dust and sandstorms, but current evidence is limited. Flooding and other extreme weather events appear to primarily cause service disruption, but more direct links to stroke may emerge. Synergies between dietary changes that reduce stroke risk and may also reduce carbon footprint are being explored. We also discuss the impact on vulnerable populations, proposed pathophysiologic mechanisms, mitigation strategies, and current research priorities. In conclusion, climate change increasingly impacts the stroke community, warranting elevated attention.