High Air Temperature Research Articles

Comprehensive study on potato drying in convective air dryer: experimental observations, mathematical modeling, and model validation

We studied the drying kinetics of sliced potatoes (Solanum tuberosum) using a tray dryer. An experiment was conducted on how the drying rate was impacted by air temperature, sample thickness, and air velocity. The study was conducted under varying temperature ranges (50°C, 60°C, and 70°C), air velocities (0.6 ms−1, 0.7 m s−1, and 0.8 m s−1), and potato slice thickness (2 mm, 4 mm, and 6 mm). The findings revealed that a higher air temperature was correlated with an increase in the drying rate, while thicker layers demonstrated a decrease in the drying rate. We further evaluated five mathematical models, with the Page Model emerging as the most suitable based on the lowest residual standard error (RSE) and Akaike's Information Criteria (AIC), which are 0.06421 and -1123.947, respectively. After plotting the predicted moisture ratio against the experimental moisture ratio, we observed an exceptional predictive accuracy (R2 > 0.99) across various conditions. These findings underscore the critical importance of precise parameter control for optimizing potato drying processes in industrial settings, providing valuable insights for enhanced efficiency and resource utilization. Further exploration into real-time optimization and scalability can extend the practical applications of this study.

THEORETICAL PERFORMANCE ASSESSMENT OF A PARABOLIC TROUGH HUMIDIFYING SOLAR COLLECTOR-BASED SOLAR STILL

In this paper, a parabolic trough humidifying solar collector-based solar still (PHSC-SS) is proposed. Its purpose is to apply some important performance improvement techniques to the flat plate humidifying solar collector-based solar still (flat plate HSC-SS), to significantly improve overall system performance. These included the use of parabolic trough solar concentrators and the design of humidifying solar collectors from evacuated tube collectors. The results reveal that, unlike flat plate HSC-SS, which must operate with a turbulent airflow regime to achieve optimum overall performance, PHSC-SS must operate with a laminar airflow regime and high inlet and outlet temperatures of air (at least 55 °C and less than 100 °C, at atmospheric pressure) in the heat collector element. For 900 W/m2 of incident solar irradiance, 2 m2 of solar collector area, and 0,00042 kg/s of air flow rate, the maximum energy efficiency, exergy efficiency and daily freshwater productivity of PHSC-SS were found to be 68,12%, 14,87% and 1,697 kg/h, respectively. Whereas for the same incident solar irradiance and solar collector area, and 0,1 kg/s of air flow rate, those of the flat plat HSC-SS were 72,9%, 1,12%, and between 1,07 – 2,923 kg/h (for inlet and outlet temperatures of air less than 30 °C, at atmospheric pressure), respectively. Although in some extreme cases freshwater productivity of flat plate HSC-SS can be higher than that of PHSC-SS, it should be noted that laminar airflow regime confers great advantages to PHSC-SS. These are higher air temperatures at condenser inlet (which ease water condensation process), no need of an auxiliary cooling device (needed in the flat plate HSC-SS), less mechanical vibrations of system, reduced condenser size, and less energy consumed by air blowers. Furthermore, the upper limit of the PHSC-SS is a PHSC-SS that operates without air flow, but rather by vaporization of water droplets at boiling point from absorber, followed by their suction to condenser, similarly to a flash evaporation.

Analyzing temperature distribution in cable cabins within utility tunnels: Developing effective ventilation strategies for local thermal environment enhancement

Convection heat transfer between the cables and the air in the cable cabin of the utility tunnel can lead to high temperatures in the cable cabin. High-temperature environments may cause the performance of cable systems to degrade, threatening the stability of the city's power supply. Increasing ACH (air changes per hour) alone could not effectively improve the high temperature at the end of the cable cabin. This paper employed numerical simulations and rigorous experimental validation to study the summer temperature field of cable cabins in Xi'an. An innovative disturbance ventilation method was proposed to alleviate the high-temperature phenomenon. The results indicated that as the wind flow length increases, the temperatures rise rapidly with the distance increased, resulting in a stable high-temperature area at the end of the cable cabin and the high-temperature air accumulated at the top by thermal buoyancy. When the ACH (air changes per hour) increased from 2 to 6, the temperature field range decreased by 3.25–6.39 %, and the variance decreased by 6.03–14.42 %. After installing a disturbance fan at the beginning of the stable zone, the temperature field in the cable cabin was fully mixed. Compared to directly increasing the ACH, the temperature field range decreased by 20.65–44.76 %, and the variance decreased by 40.28–64.47 %. The introduction of a disturbance fan could thoroughly mix the air and effectively improve the local thermal environment in the cable cabin. This study contributed to the optimization of cable cabin ventilation strategies.

Influence of meteorological factors on the moisture content of fine forest fuels: responses of fire danger class to different microclimates on the example of European beech (Fagus sylvatica L.) stands

Abstract Due to the increased number of forest fires, a detailed examination and knowledge of the effects of the microclimatic conditions of forests is currently significant. The study carried out in Arboretum Borova hora (Slovak Republik), investigates the influence of meteorological factors (air temperature, relative humidity), the value of the Angström index, and the danger class of the Angström index on the moisture content of fine fuel at the edge of a beech forest stand, but also in its interior. We tested three working hypotheses: a) meteorological conditions differ significantly between the edge and the interior of the beech forest, b) the moisture content of fine fuel is higher in the beech forest interior than at the forest edge, c) the Angström index fire danger class is higher at the edge of the beech forest than in its interior. We created a calibration curve that was also used to measure the humidity of beech leaves with the help of the ME 2000 hygrometer. Our results show that edge beech stands are significantly more susceptible to fires, lower air humidity and fine fuel moisture content, and higher air temperatures than forest interiors. From our point of view, the microclimate is considered the main factor that explains the difference between the vegetation structure of the forest edge and the forest interior.

Hyporheic exchange flows in a mountainous river catchment identified by distributed temperature sensing

AbstractElevated stream temperatures under low‐flows, exacerbated by global warming, are a stressor that affects aquatic species directly or in combination with other stressors. Stream temperatures are influenced by energy fluxes across the air–water interface as well as by hydrological exchange processes occurring at the water–riverbed interface. Small‐scale stream temperature dynamics influenced by exchange flows are still underrepresented in stream temperature research. To investigate high‐resolution temperature dynamics and hydrological exchange processes at the sediment–water interface we applied fiber‐optic distributed temperature sensing (FO‐DTS) at two sites in the mountainous Kinzig catchment combined with mapping and measurement of additional environmental conditions. Two types of temperature anomalies could be observed at one site under conditions of low flow and high air temperature. Dampening effects coincided with riverine features such as pools, vegetation roots, fine sediment, and signs of streambank seepage which indicated hyporheic exchange flows. Increased heating of the substrate during the day was identified in shallow sections where sediment was exposed to the air and shading from riparian vegetation was patchy. At another site, at which the cable could not be buried because of the sediment composition, temperature anomalies in the overlying water indicated diffuse groundwater exfiltration. The results show that small‐scale processes in the hyporheic zone, low water tables, and riparian shading influence stream temperature in mountainous streams and can be identified with FO‐DTS under suitable conditions. The results improve our understanding of stream temperatures (in the hyporheic zone) and provide important information on how to improve hydrological modeling.

Drying techniques for precooked hybrid rice to ensure quality of instantized rice

AbstractBackground and ObjectivesDue to the emergence of new hybrid rice cultivars, rice processors must refine their processing protocols to maintain the production of high‐quality products. This is crucial for the instant rice processing industry. Therefore, this study aims to refine current convective heated air‐drying processing methods to suit the new hybrid rice cultivars intended for instant rice production. New strategies to dry cooked rice were investigated. These included drying in a stepwise manner with high (230–200°C) and medium (190–160°C) air temperatures and drying at constant high (200°C) and medium (160°C) air temperatures. Changes in quality attributes of two new long‐grain (LG) hybrid rice cultivars (XL 753 and RT 7521 FP), including rehydration ratios, texture, color, and bulk density, were examined after using the modified drying strategies.FindingsThe percentage points of moisture removed were significantly affected by cultivar type, cooked rice drying air temperatures, and relative humidity (RH) (p < .05). Additionally, the rehydration ratio of instantized rice was significantly influenced by the drying air temperature (p = .0361). The highest rehydration ratio (3.14) was observed for cultivar XL 753, which was dried at a constant air temperature of 160°C and 40% RH, whereas the lowest (2.77) was observed with the same cultivar when dried at a constant air temperature of 200°C and 40% RH. The bulk density and volume increase ratio were impacted by cultivar type (p < .05), while drying air temperature and RH did not have significant effects on the volume increase ratio. Water activity values ranged from 0.53 to 0.56 for both cultivars and were influenced by drying air temperature, while color was affected by RH (p < .05). Textural parameters (hardness, adhesiveness, springiness, and cohesiveness), except resilience and springiness, were significantly affected by cultivar type, while drying air temperature had significant impacts on all textural parameters.ConclusionsPrediction profiler for multi‐attribute optimization using a desirability function approach from JMP suggested the XL753 cultivar, an RH of 20%, and Stepwise High as the drying treatment. Under these settings, the predicted percent point of moisture content loss, rehydration ratio, ΔE value (color), bulk density, hardness, adhesiveness, springiness, and cohesiveness of the models were 36.75, 9.44, 0.33, 2.95 g/mL, 3941.60 g, −14.17 gs, 0.72, and 0.59, respectively. The study provides crucial information for guiding decisions on drying conditions for industrial processing of instantized rice that may yield the most desirable quality attributes. Different rice cultivars may have differences in the quality of instant rice; however, the drying treatment found to work best in this study should be valid for all rice cultivars.Significance of StudyThe study has provided crucial information on the possibility of modifying convective heated air‐drying methods to improve the quality attributes of instant rice made from new hybrid rice cultivars. Information generated from this study may be useful to guide decisions on drying conditions for industrial processing of instantized rice with premium quality.

Geographic variation in the acoustic signals of lesser treefrogs Dendropsophus minutus (Anura, Hylidae)

Biological sound archives are a major source to investigate geographic variation in animal acoustic signals and their evolutionary drivers. The acoustic signals of anuran species with wide distribution ranges often vary geographically as a result of isolation by distance and climate amongst other factors. We examined whether the acoustic structure of call notes would vary geographically in lesser treefrogs Dendropsophus minutus using recordings from bioacoustics repositories. We also tested whether climate (mean annual temperature and annual precipitation) drive geographic variation in those signals. The acoustic distance was unrelated to geographic distance, suggesting that isolation by distance solely cannot explain geographic variation in call structure. Overall, lesser treefrogs uttered call notes with lower frequencies and bandwidths in the west of their range. In addition, frogs produced shorter call notes in hotter, wetter sites and narrow-bandwidth notes in hotter environments. We suggest that frogs produce more calls (not measured here) of shorter durations to maximize transmission and minimize the metabolic costs of calling at high air temperatures. We also suggest that hotter environments favor the propagation of lower-bandwidth calls. This study reinforces the feasibility and power of citizen science and acoustic data repositories for understanding the evolution of anuran acoustic signals.

The assessment of chlorophyll-a retrieval algorithm and its spatial-temporal distribution using sentinel-2 MSI off the Banjir Kanal Timur River, Semarang, Indonesia

In aquatic ecology, Chlorophyll-a (Chl-a) plays a pivotal role in biogeochemical cycles, as well as a key indicator for the trophic state in the environment. Coastal area of Semarang is known as eutrophic waters. Thus continuous monitoring of Chl-a will be beneficial for the management of the impact of the trophic dynamic in the coastal waters of Semarang. Taking the benefit of the continuous monitoring of satellite measurement, the present study provides the assessment of Chl-a off the Banjir Kanal Timur (BKT) River, Semarang, using the proper remote sensing approach. In this study, algorithms were generated according to bands sensitive to Chl-a scattering properties, using multiple regression between in-situ Chl-a and Bottom of Atmospheric (BoA) reflectance from Sentinel-2 with 10 m resolution. A total of 43 water samples were collected to build the algorithm and 43 of the water samples were used for validation during the passing time of Sentinel-2 at the equator i.e., on 21 August 2021 at 9.00–11.00 local time. The results show that the performance of the algorithm generated in this study has high accuracy as denoted by the low RMSE, and MAPE, respectively. For the seasonal variation, the highest (lowest) concentration of Chl-a is observed in December (September), with values reaching 11.92 µg/L (7.06 µg/L). The seasonal fluctuation of Chl-a depends on air temperature and sunshine duration. High (low) air temperature and long (short) duration of solar exposure result in increased (decreased) Chl-a off the BKT River. Conversely, the elevated wind velocity only impacts the rise of Chl-a in the region far from the river estuary, which is associated with the mixing process. BKT waters are categorized as eutrophic conditions, with a concentration exceeding 6 µg/L. These algorithms can provide valuable insights into the health and productivity of coastal ecosystems, aiding in their monitoring and management.

Environmental adaptability of spring durum wheat (<I>Triticum durum</I> Desf.) cultivars developed in Saratov

Background. The spreading of drought-resistant spring durum wheat cultivars with high grain quality developed by Saratov breeders to the eastern regions of Russia is dictated by climate change: higher air temperatures, precipitation deficit during the growing season, and summer droughts.Materials and methods. The material for research included seven spring durum wheat cultivars developed at the Federal Center of Agriculture Research (FCAR) of the South-East Region in Saratov: ‘Valentina’, ‘Nik’, ‘Yelizavetinskaya’, ‘Nikolasha’, ‘Luch 25’, ‘Pamyati Vasilchuka’, and ‘Tamara’. The cultivars and their yields in 2012–2022 were evaluated to calculate the coefficients of environmental plasticity and stability according to the methods by S. A. Eberhart and B. A. Russell, as interpreted by V. A. Zykin. Grain quality indicators were measured on the devices: Infratec 1241 for protein, Glutomatic for the index of gluten (IG), and Spekol 10 for the yellowness index (b%).Results. The adaptability of spring durum wheat cultivars bred in Saratov was confirmed by the coefficients of environmental plasticity and stability. According to the results of the study, cvs. ‘Nik’, ‘Nikolasha’, ‘Luch 25’ and ‘Pamyati Vasilchuka’ with plasticity coefficients (bi) > 1 were highly responsive to the conditions of cultivation and production of high-quality grain.Conclusion. The data obtained on grain productivity and high quality make it possible to recommend drought-resistant cultivars released by the FCAR of the South-East Region for use in various regions of Russia.

Numerical Investigation of In-Cylinder Combustion Behaviors in a Medium-Speed Diesel Engine

Abstract This study aims to advance understanding of in-cylinder combustion processes in medium-speed diesel engines, which are extensively employed in heavy-duty applications where electrification proves inefficient yet remains insufficiently examined in the literature. By modeling a four-stroke engine with dimensions of 210 mm bore and 310 mm stroke, operating at 900 rpm under full load, this research identifies distinct combustion characteristics that differentiate medium-speed engines from their high-speed counterparts. Key findings illustrate that super turbocharging in medium-speed engines enhances the combustion of the fuel–air mixture under elevated temperatures and pressures. Moreover, an increased stroke length promotes gas velocity and turbulence, facilitating fuel atomization and mixing. Notably, rapid fuel ignition occurs near the nozzle due to the high temperature of compressed air, reducing the ignition delay. As a result, the premixed combustion stage nearly disappears, with diffusion combustion dominating, especially pronounced with long-duration injection, a characteristic of medium-speed engines. The study also reveals a more uniform but elevated distribution of nitrogen oxide emissions in medium-speed engines, attributed to prolonged high-temperature conditions that both facilitate their formation. Early stages of diffusion combustion show high concentrations of incomplete combustion products. However, as the combustion process progresses, the conditions favor the complete oxidation of these products at high temperatures, resulting in decreased carbon-based pollutions. In addition, the larger combustion chamber and enhanced turbulence characteristic of medium-speed engines support efficient fuel and air mixing without necessitating the swirl effect required by high-speed engines, diminishing the dependence on wall impingement dynamics for air utilization. Consequently, efficiency optimization strategies for medium-speed engines, emphasizing adjustable injection parameters, encounter fewer constraints than those inherent to the spatial limitations of high-speed engines.

Zero-dimensional analysis of the effect of water vapor on reducing electrons in the plasma sheath

In this study, an air-water vapor ionization reaction model is developed within the quantum-kinetic (Q–K) model of the direct simulation Monte Carlo method to investigate the detailed mechanism of how water vapor reduces electrons. The zero-dimensional simulations of a typical non-equilibrium flow field downstream of a normal shock are designed, where the electron number density decreases by two orders of magnitude due to water vapor. We conclude that the introduction of water vapor reduces the mole fractions of oxygen atoms and nitrogen atoms through five pairs of reactions and enhances the reverse nitric oxide associative ionization reaction, leading to electron consumption. The phenomena and corresponding mechanisms under varying mole fractions of water vapor, air temperatures, and water vapor temperatures are investigated. Based on the mechanisms, we propose that the addition of hydrogen ions could improve the water's mitigation effect, which is then proven to be able to reduce the electron number density by another two orders of magnitude, not only at high air temperatures but also at lower air temperatures or lower mass injection rates.

The Critical Ambient Temperature Threshold for Safe Fan Use in Young Adults During Extreme Heat Exposure

Introduction: The electric fan may be an effective, low-cost heat resilience solution during extreme heat. Fans have been shown to attenuate the rise in cardiovascular and thermal strain relative to still air in young adults, particularly during exposure to more humid conditions. When ambient temperature exceeds skin temperature, a fan improves sweat evaporation from the skin surface, which counterbalances the increased rate of convective heat gain. However, at higher air temperatures, the increased convective heat gain may exceed the rate of evaporative heat loss resulting in net heat gain and increasing physiological strain. The purpose of the present study was to identify the critical ambient temperature limit, where increased physiological strain will be observed, with a fan in comparison to still air. Method: To date, 6 participants (4 females; 24±9 y; 72.8±17.8 kg; 1.8±0.2 m) have completed two 180-minute temperature ramp heat-exposures (37°C to 47°C at ~0.05°C/min, 25%RH) on separate days. Wearing standardized t-shirts and shorts, the participants remained seated while either i) facing an electric fan (5.3±0.9 m/s) or ii) in still air (0.1±0.0 m/s). Rectal and skin temperature, heart rate, blood pressure, whole-body sweat loss, thermal comfort, and thermal sensation were measured every 10 minutes. Results: Rectal temperature was similar between fan and still air up to 43°C (P>0.92), however was greater with a fan from 44°C onwards (p<0.05). Skin temperature was higher with a fan compared to still air throughout the exposure (p<0.001). Heart rate was similar between fan and still air until 44°C (P>0.61), after which heart rate was higher with a fan (p<0.05). Mean arterial pressure was not different between fan and still air at any air temperature (P=0.53). The rate pressure product was higher with a fan compared to still air when the ambient temperature exceeded 44°C (p<0.05). Whole-body sweat losses were greater with a fan (1215±250 g) compared to still air (675±103 g, P=0.006). No differences between fan and still air were observed for thermal comfort (P=0.22) or thermal sensation (P=0.73) throughout the temperature ramp protocol. Conclusion: When ambient temperature exceeds 43°C, electric fan use results in greater physiological strain at rest in young healthy adults relative to still air. This research was supported by Dr. Ravanelli’s Natural Sciences and Engineering Research Council of Canada Discovery Grant (PIN#2022-05096). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Lethal combination for seedlings: extreme heat drives mortality of drought-exposed high-elevation pine seedlings.

Hotter drought- and biotically-driven tree mortality are expected to increase with climate change in much of the western United States, and species persistence will depend upon ongoing establishment under novel conditions or migration to track ecological niche requirements. High-elevation tree species may be particularly vulnerable to increasing water stress as snowpack declines, increasing the potential for adult mortality and simultaneous regeneration failures. Seedling survival will be determined by ecophysiological limitations in response to changing water availability and temperature. We exposed seedlings from populations of Pinus longaeva, Pinus flexilis, and Pinus albicaulis to severe drought and concurrent temperature stress in common gardens testing timing of drought onset under two different temperature regimes. We monitored seedling functional traits, physiological function, and survival. The combined stressors of water limitation and extreme heat led to conservative water use strategies and declines in physiological function, with these joint stressors ultimately exceeding species' tolerances and leading to complete episodic mortality across all species. Growing conditions were the primary determinant of seedling trait expression, with seedlings exhibiting more drought-resistant traits such as lower specific leaf area in the hottest, driest treatment conditions. Water stress-induced stomatal closure was also widely apparent. Under adequate soil moisture, seedlings endured prolonged exposure to high air and surface temperatures, suggesting broad margins for survival. The critical interaction between soil moisture and temperature suggests that rising temperatures will exacerbate growing season moisture stress. Our results highlight the importance of local conditions over population- and species-level influences in shaping strategies for stress tolerance and resistance to desiccation at this early life stage. By quantifying some of the physiological consequences of drought and heat that lead to seedling mortality, we can better understand the future effects of global change on the composition and distribution of high-elevation conifer forests.

Microclimate and the thermal comfort during the implementation of silvopastoral systems: the windbreak countereffect.

Little has been studied about microclimate and the thermal comfort during the implementation of silvopastoral systems. This study aimed to evaluate the microclimate and thermal comfort during the implementation of High Biodiversity Silvopastoral System with Nuclei (SPSnu). Three treatments were investigated, SPSnu with 5 and 10% of the pasture area with nuclei, (SPSnu5 and SPSnu10, respectively), and treeless pasture (TLP). Each treatment was subdivided into 4 areas: within the nuclei, around the nuclei, around the nuclei with shade and internuclei. The analyzed variables were soil surface temperature, air temperature, wind speed, relative humidity, black globe temperature and the Heat Load Index (HLI) at 20 and 120cm height. We hypothesized that the wind speed reduction associated with insufficient shade projection typical of the first years of SPSs may interfere in microclimate and thermal comfort during the hot seasons. SPSnu5 and SPSnu10 had a reduction in wind speed of 51.58% and 68.47% respectively when compared to TLP at 20cm. Soil surface temperature and air temperature at 120cm were higher for SPSnu than TLP. The same effect was observed for the HLI. At 20cm, HLI indicated better thermal comfort in TLP than in the SPSnu treatments. The lack of shade projection from young nuclei in conjunction with the decrease of wind speed between the nuclei caused a higher air temperature and HLI in the SPSnu treatments, we called this conditions, windbreak countereffect. Farmers must knowledge this effect when implementing SPSs, and when necessary, mitigate with the proper management decisions.

Traces of Local Adaptive Acclimatization Response in the Tracheid Anatomical Traits between Dry and Wet Mesic Norway Spruce (Picea abies) Forests in Moravia, Czech Republic?

Norway spruce (Picea abies) forests in temperate zones are already reacting to short-term extreme summer heatwaves, threatening the vitality of trees and forest productivity, and can even lead to local and regional dieback events. Examining quantitative wood anatomy can provide helpful information in terms of understanding the physiology mechanisms and related responses of conifer trees to local environmental interactions in relation to tracheid adaptive capacity. This study analysed the tracheid functional anatomical traits (FATs) plasticity of six young Norway spruce trees growing in two mesic research plots with high annual precipitation (~43%) and air temperature differences during 2010–2017. The research plots are located in the sub-mountainous (Rájec Němčice) and mountainous (Bílý Kříž) belts of the Moravia region, Czech Republic. Vapour pressure deficit and cell wall reinforcement index (CWRI) were shown to be the most representative environmental parameters as proxies of dry conditions. Tracheid FATs indicated latewood phenological plasticity sensitivity, with more pronounced variability in the warmer and drier plots. Latewood tracheids of Norway spruce trees grown in the RAJ formed significantly thicker cell walls than BK during the studied period. The observed differences between the two research plots indicate additional support for tracheid cells’ hydraulic safety against cavitation and potential traces of adaptive acclimatization response.

Assessment on oxidation behaviors of high chromium white iron matrix composite in high temperature air environment

Oxidation behaviors of in situ formed TiCx/high chromium white iron (TiCx/HCWI) composite containing trace alloying elements with super hardness were investigated in air at 650 °C and 700 °C for 96 h, respectively. Rich types of oxides appeared on the oxidized surfaces of the TiCx/HCWI composite both at 650 °C and 700 °C. While, MoO3 appeared on the surface only at 650 °C, FeV2O4 turned up only at 700 °C. The various oxides were enriched in diverse regions inside and outside the oxide layer at 700 °C due to the discrepancy of oxidation thermodynamics and oxidation partial pressure. Oxidation thermodynamics, kinetics, and oxidation mechanisms of the TiCx/HCWI composite were discussed. The present work provides enlightenment for the application of the super hard TiCx/HCWI.

Conflicting Changes of Vegetation Greenness Interannual Variability on Half of the Global Vegetated Surface

AbstractChanges in the interannual variability (IAV) of vegetation greenness and carbon sequestration are key indicators of the stability and climate sensitivities of terrestrial ecosystems. Recent studies have examined the changes in the vegetation IAV using atmospheric CO2 observations and dynamic global vegetation models (DGVMs), however, reported different and even contradictory IAV trends. Here, we investigate the changes in the IAV of vegetation greenness, quantified as coefficient of variability (CV), over the past few decades based on multiple satellite remote sensing products and DGVMs. Our results suggested that, on half of the global vegetated surface (mostly in the tropics), the CV trends detected by different satellite remote sensing products are conflicting. We found that 22.20% and 28.20% of the global vegetated surface (mostly in the non‐tropical land surface) show significant positive and negative CV trends (p ≤ 0.1), respectively. Regions with higher air temperature and greater aridity tend to have increasing CV trends, whereas greater vegetation greening trend and higher nitrogen deposition lead to smaller CV trends. DGVMs generally cannot capture the CV trends obtained from satellite remote sensing products, while the inconsistency among satellite remote sensing products is likely caused by their process algorithms rather than the sensors utilized. Our study closely examines the changes in the IAV of global vegetation greenness, and highlights substantial uncertainty when using satellite remote sensing to study the response of terrestrial ecosystems to climate change.

Novel multi-hierarchical nanofiber aerogel for high efficient filtration of high-temperature flue gas

Fibrous air filtration materials are highly effective at capturing particulate matter (PM) from emissions. Yet, many commercially available filters are difficult to achieve high filtration efficiency for PM while maintaining low filtration resistance. Furthermore, the elevated temperatures (ranging from 100.0 to 250.0 °C) commonly associated with pollution sources necessitate stringent thermal resistance requirements for filtration materials. Here, a new strategy for the preparation of aerogels for high-temperature gas filtration is reported. Firstly, a unique “grooved and secondary pore” structure polyaryl thioether sulfone (GPASS) nanofibers are initially fabricated using a combination of “wet” electrostatic spinning and aqueous etching. And then, the oxidized GPPASS aerogel (O-GPPASS) can be obtained through simple acid and freeze-dried treatment. It is found that the as-prepared aerogel exhibits high filtration efficiency of 99.7 % for PM0.3, accompanied by low pressure drop of 17.2 Pa, and high quality factor (QF) of 0.362 Pa−1. Remarkably, after enduring high-temperature conditions of 330.0 °C for 4.0 h, the O-GPPASS aerogel still maintains an impressive filtration performance, with a 99.6 % efficiency and a pressure drop of 17.6 Pa for PM0.3 particles. It will well meet the needs of filter materials used in high temperature environments. This innovation is poised to supersede traditional high-temperature air filtration materials, paving the way for sustainable advancements in industrial applications.

Open-cup nesters in the Kalahari: Incubation and egg-shading behaviour in passerines cannot be detected with temperature dataloggers during hot periods

Birds that build open-cup nests in semi-arid or arid habitats have difficulty in maintaining clutch temperatures during incubation in a suitable incubation range due to high air temperatures and solar radiation, resulting in either embryo death or behavioural responses to preserve clutch viability. We investigated how Southern Fiscals (Lanius collaris), open-cup nesting passerines with female-only incubation in the Kalahari basin, allocated time for self-care (off-bouts) and incubation (on-bouts) and whether egg shading, a previously described behaviour in this species, is a widespread response during hot periods. We used a dual approach combining temperature dataloggers in the nest and behavioural observations during the hottest hours of the day. We found that in the early morning and late evening, Southern Fiscals behaved similarly to species incubating in temperate habitats by alternating off- and on-bouts, but during the hottest hours of the day, shading became the main activity. Behavioural observations were key to describing this behaviour indicating that it is necessary to combine different data collection strategies to successfully assess the behaviour of open-cup nesters in hot environments.

Assessing the influence of climate controls on grapevine biophysical responses: a review of Ontario viticulture in a changing climate

Climate change presents unique challenges for grape growers across the world. In Ontario, three distinct viticultural regions are experiencing climatic shifts towards warmer growing seasons. According to historical records collected from Environment and Climate Change Canada, Lake Erie North Shore has transitioned from an intermediate-to-warm growing season classification, the Niagara Peninsula from the lower to upper limits of the intermediate zone, and Prince Edward County from cool to intermediate, when analyzing their average growing season temperatures. Terroir is directly related to vine water status, an indicator of grapevine stress. Biophysical responses controlled by air temperature and precipitation include fluctuations in vapour pressure deficits, evapotranspiration, and water-use-efficiency rates, as well as soil water content levels. By conducting an extensive literature review, the development of a conceptual model addresses how variations in climatic controls, under the scope of climate change, may influence grapevine water status, biophysical responses, and associated production outcomes for Ontario vineyards. Cool-to-intermediate air temperatures, when paired with increased precipitation will lead to no or low vine stress, increasing photosynthesis and transpiration rates, and variable plant water-use-efficiency levels, producing higher yields and lower quality grapes, if no management strategies are applied. Oppositely, higher air temperature as a product of climate change, when paired with variable precipitation may produce mild-to-severe stress, reducing yield, and increasing grape quality. With the appropriate management strategies, both traditional and new, growers may be able to accommodate for the influence of climate change on their vineyards.