Vapor Pressure Research Articles

The Impact of Climate on Human Dengue Infections in the Caribbean.

Climate change is no longer a hypothetical problem in the Caribbean but a new reality to which regional public health systems must adapt. One of its significant impacts is the increased transmission of infectious diseases, such as dengue fever, which is endemic in the region, and the presence of the Aedes aegypti mosquito vector responsible for transmitting the disease. (1) Methods: To assess the association between climatic factors and human dengue virus infections in the Caribbean, we conducted a systematic review of published studies on MEDLINE and Web of Science databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. (2) Results: In total, 153 papers were identified, with 27 studies selected that met the inclusion criteria ranging from the northern and southern Caribbean. Rainfall/precipitation and vapor pressure had a strong positive association with dengue incidence, whereas the evidence for the impact of temperatures was mixed. (3) Conclusions: The interaction between climate and human dengue disease in the Caribbean is complex and influenced by multiple factors, including waste management, infrastructure risks, land use changes, and challenged public health systems. Thus, more detailed research is necessary to understand the complexity of dengue within the wider Caribbean and achieve better dengue disease management.

Triadic Halobenzene Processing Additive Combined Advantages of Both Solvent and Solid Types for Efficient and Stable Organic Solar Cells.

Solvent additives with a high boiling point (BP) and low vapor pressure (VP) have formed a key handle for improving the performance of organic solar cells (OSCs). However, it is not always clear whether they remain in the active-layer film after deposition, which can negatively affect the reproducibility and stability of OSCs. In this study, an easily removable solvent additive (4-chloro-2-fluoroiodobenzene (CFIB)) with a low BP and high VP is introduced, behaving like volatile solid additives that can be completely removed during the device fabrication process. In-depth studies of CFIB addition into the D18-Cl donor and N3 acceptor validate its dominant non-covalent intermolecular interactions with N3 through effective electrostatic interactions. Such phenomena improve charge dynamics and kinetics by optimizing the morphology, leading to enhanced performance of D18-Cl:N3-based devices with a power conversion efficiency of 18.54%. The CFIB-treated device exhibits exceptional thermal stability (T80 lifetime = 120h) at 85°C compared with the CFIB-free device, because of its morphological robustness by evolving no residual CFIB in the film. The CFIB features a combination of advantages of solvent (easy application) and solid (high volatility) additives, demonstrating its great potential use in the commercial mass production of OSCs.

Preparation and characterisation of sodium chloride-doped CaO-Al2O3-SiO2 system glass-ceramics

ABSTRACT It is known that the treatments of chlorine-containing wastes, such as municipal solid waste incineration fly ash are particularly challenging. One method for treating chloride is to entrap it in glass by melting. It has been demonstrated that CaCl2 can be retained in CAS system glass-ceramics. However, as the main chloride, NaCl exhibits a low boiling point and a high vapour pressure. The fixation of NaCl and its effect on glass-ceramics remain unclear. In this study, 2.17% Cl− was incorporated into the base glass by limiting NaCl volatilisation during melting. Glass-ceramics were successfully prepared using the Cl-containing glass powder as the raw material by sintering and the chloride was evenly distributed between the glass phase and crystalline phase. The primary crystal phases observed were wollastonite and anorthite. Furthermore, when the sample was sintered at 825 °C for 4 hours, it exhibited a bending strength of 155 MPa and a hardness of 6.29 GPa. This method can effectively address the resourceful treatment of chlorine-containing wastes.

Surface modification effects on ammonium perchlorate wettability

Solid propellants are commonly used for propulsion systems due to their high volumetric thrust and reliability. Powder bed, binder jetting manufactured propellants will enable unique geometries to be made that are necessary for designers to achieve high thrust levels. However, changes to the particulate wettability from the solvent-based manufacturing technique must be understood such that propellants with adequate mechanical properties are achieved. In this work, the wettability of ammonium perchlorate (AP) crystal surfaces is quantified with solvent and air plasma treatments. Removal of adventitious carbon from AP surface decreases the polybutadiene contact angle from 34 ± 1° to 15 ± 4°. The presence of hydrocarbons from non-polar solvents used in this study with lower vapor pressure was observed to have a similar effect as the adventitious carbon whereas higher vapor pressure solvents have minimal influence on the final wettability of AP surfaces. Polar solvents were determined to alter the surface topology by creating a more hydrophobic surface when compared to the plasma treated samples. An increase in concentration of amine surface groups overcomes the decrease in wettability from carbonaceous residue and surface morphology. The extension and implications of these findings to powder bed, binder jetting manufacturing for propellants is discussed.

Effect of hydrogen on oxidative dissolution of epsilon particles-doped UO2 pellets under carbonate condition with hydrogen peroxide

The epsilon particles that result from nuclear fission of UO2 fuel possess both advantages and disadvantages from a spent nuclear fuel (SNF) management perspective. In this study, the effect of epsilon particles, namely Ru, Mo, and Pd, inherent in simulated UO2 pellets is examined. Various analytical methods have been used to explore the changes in the structural, surface, and electrochemical properties of which contain epsilon particles. A notable finding is that the epsilon particles are not evenly distributed and tend to clump together, transforming into a metallic state after sintering, as detailed in the X-ray diffraction analyses. Energy-dispersive X-ray spectroscopy analyses highlight interesting aspects of the distribution of elements, especially the disappearance of Pd during sintering, which is likely due to its high vapor pressure. Although the lattice structure of UO2 remains unchanged, the sizes of the grains and pores visibly change, which may influence the tendency of UO2 pellet-cracking. Despite the addition of the epsilon particles, the electrical conductivity analyses show no significant changes, suggesting that they act as minor impurities without affecting the structural lattice. However, their possible role as catalysts in electrochemical reactions opens new and interesting areas that require thorough investigation. Moreover, examining the anodic dissolution under various conditions provides detailed insights into UO2 dissolution and oxidation, revealing how epsilon particles subtly influence the oxidative dissolution process. This study clarifies the basic interactions and effects of epsilon particles in UO2 pellets and broadens the path for a deeper understanding and improvement of nuclear fuel matrices and steering advancements in the safe and effective use of nuclear energy.

Factors and quantitative impact on electrical yield in fishery complementary photovoltaic power plant under different cloud cover conditions

The electrical yield of fishery complementary photovoltaic (FPV) power plants can be self-sustained through aquaculture, offering certain advantages over land-mounted photovoltaic systems. However, electrical yield was affected by environmental factors. The screening of impactful factors and quantification of the relationship between electrical yield and these factors are difficult for FPV power plants because of lacking observation materials. Therefore, electrical yield and its main impactful factors under various cloud cover conditions through in-situ observations were investigated in this study. The results indicated that distinct variations in electrical yield and impactful factors with different clearness index. Downward shortwave radiation (DSR), panel temperature, and vapor pressure deficit (VPD) jointly impact electrical yield. When panel temperature is below 30 °C, electrical yield capacity increases by 10 kWh for every 1 W m⁻2 rise in DSR. Moreover, a 1 kPa rise in VPD results in an approximate 9.50 kWh increase in electrical yield for each 1 W m⁻2 rise in DSR. This study will be crucial for effective electrical yield management planning for aquaculture in FPV power plants.

Pediatric appendicitis may be co-associated with meteorologic factors: A case-crossover study

BackgroundThe etiopathogenesis of appendicitis is still not fully understood. Few reports have researched the impact of weather as a cofactor for the development of appendicitis. MethodsTo investigate the potential association between the development of appendicitis and exposure to ambient meteorological conditions, a retrospective case-crossover study was conducted. Publicly available meteorologic data were matched with those from 1343 patients aged ≤19 years with histologically confirmed acute (AA; n = 996) or perforated appendicitis (PA; n = 347) treated at our pediatric surgical hospital between October 2001 and October 2018. ResultsA time-stratified conditional logistic regression analysis revealed increased odds ratios (ORs) for AA of 4–5% for each 1 hPa increase in vapor pressure during each 3–7 day cumulative moving averages (CMA) lag preceding appendectomy. This effect was stronger on stratification by age class >10 years (OR 1.05–1.08; 3–7-day CMA) and during spring (OR 1.08–1.09; 4–7-day CMA). Moreover, each 1% increase in relative humidity on the day of appendectomy was associated with a 2% decrease in the OR for PA, which was 4% during autumn under seasonal stratification. ConclusionThe role of meteorologic factors in the development of appendicitis remains largely unclear. In accordance with the literature, our results show that seasonal variations together with exposure to altered levels of humidity and vapor pressure may impact patients at different grades of appendiceal inflammation. Thus, transient fluctuations in meteorologic and seasonal variables may constitute cofactors that potentially influence the occurrence and course of pediatric appendicitis.

Alkali alkanoate ionic liquids for thermal energy storage at mid-to-high temperature: Synthesis and thermal–physical characterization

Thermal energy storage is gaining much attention and experiencing a renascence in last years. In this sense, storing thermal energy in form of latent heat is of special interest due higher energy density, lower energy losses and higher energy efficiency. To store thermal energy as latent heat the presence of a phase change material (PCM) is needed and its performance the key for its implementation in a thermal energy storage (TES) system and the temperature at which the phase change takes place, low (<150 °C) or high (>150 °C) temperature, will condition the application of a given PCM. In this context, the development of PCM materials to store latent heat at mid-to-high temperature in between 150 °C and 350 °C is of special interest e.g., in the field of concentrated solar power or heat recovery. There are already some solid–liquid phase change materials working in this range of temperature e.g., sugar alcohols, aromatic organic compound, inorganic salts, or blend of inorganic salts but all of them present different drawbacks, such as vapor pressure, degradation, low thermal conductivity, corrosion, etc. In consequence, there is a need to explore new PCM materials in this range of temperature applications. In this context, ionic liquids could play a key role in the development of novel PCMs due to their intrinsic properties. Indeed, ILs are gaining increased attention in the field of thermal energy storage in the last years but mainly in the low temperature range (<150 °C) remaining their application in the mid-to-high temperature range in between 150 °C and 350 °C underestimated. In this work, we prepared six different alkali alkanoate ionic liquids, namely [Na][MeOC2], [K][MeOC2], [Na][MeOC3], [K][MeOC3], [Na][MeOC4] and, [K][MeOC4] by direct reaction between the desired methyl methoxycarboxylate ester with NaOH or KOH. The prepared ionic liquids were structurally characterized, and their thermal–physical properties evaluated. Five of them but [K][MeOC3] showed good enthalpy values ranging from 119 J/g to 197 J/g and four of them [Na][MeOC2], [K][MeOC2], [Na][MeOC4] and, [K][MeOC4] have showed excellent thermal stability above 380 °C. In addition, these four ionic liquids have successfully passed the cyclability test showing no significant enthalpy losses (between 0 % minimum and 7 % maximum) after 50 heating/cooling cycles compiling with the cycling category F of the RAL-GZ 896 (Quality Association PCM). All in all, these prepared ionic liquids surpass sugar alcohols in terms of cyclability and thermal stability and are comparable with the inorganic salts e.g. NaNO3 employed in the studied range of mid-to-high temperature (150–350 °C).

Thermodynamics-based sealing method for anodized aluminum used in semiconductor processing apparatuses

A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses. Thermodynamic calculations and Fick's second law were used to reveal trends in the metal ion deposition, deposition product stability, vapor pressures of halides for selected metal ions, the holding temperature, and time. Interactions between ion concentrations and the sealing temperature were also revealed. According to the design principles, anodized aluminum dipped in 1 mM Cr3+ ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.% HCl solution and HCl gas, verifying the designed results.

Spatiotemporal Characteristics and Triggers of Flash Droughts across All the River Basins in India

Abstract Flash droughts (FDs) have attracted widespread attention in recent years due to their sudden onset and rapid intensification with significant impacts on ecosystems, water resources, and agriculture. These features of FDs pose unique challenges for their forecast, monitoring, and mitigation. The impact of FDs on society can vary depending on several factors, such as the frequency of their occurrence, rate of intensification, and mean severity, which are not well understood and remain unclear specifically over India. This study developed a novel approach to quantitatively define FD based on the aridity index. This new approach was used to examine spatiotemporal characteristics (including trends) and triggers of FDs over 25 river basins across India from 1981 to 2021. The hydrometeorological conditions, including soil moisture percentiles, anomalies of precipitation, temperature, and vapor pressure deficit were investigated at different stages of FD. Results suggest that FDs with high intensification rates are more common in humid areas compared to subhumid and semiarid areas. Both precipitation and temperature are primary triggers of FDs over a major part of the study area. The individual effects of soil moisture and precipitation also act as a trigger across some regions (like northeast India and the Western Ghats). Additionally, atmospheric aridity can create conditions conducive to FDs, and when combined with depleted soil moisture, it can accelerate their rapid onset. Besides the scientific novelty, the findings of this study will facilitate policymakers to formulate effective strategies to mitigate the consequences of FDs on water resources and agriculture in India. Significance Statement Flash droughts have attracted widespread attention due to their sudden onset and rapid intensification with significant impacts on multiple vectors. The impact of flash drought on society depends on their frequency, rate of intensification, and mean severity, which are not well understood and remain unclear specifically over India. This study develops a novel approach to quantitatively define flash drought based on the aridity index. This new approach is used to examine spatiotemporal characteristics and triggers of flash drought over 25 river basins across India from 1981 to 2021. Besides the scientific novelty, the findings of this study will facilitate policymakers to formulate effective strategies to mitigate the consequences of FDs on water resources and agriculture in India.

The volatilization law of standard impurity elements in 3 N antimony during vacuum distillation and preparing antimony with 4 N8 content

A novel process for the production of high purity antimony (99.998 wt%) from crude antimony (3 N) by a two-step vacuum distillation was proposed. The process involves the volatilization of impurities (Mg, Na, Zn, As) with low boiling points, leaving antimony in the residue, followed by the retention of impurities (Fe, Si, Pb, Bi, Mn, Cu, Al, Au) with high boiling points in the residue. The feasibility of separating antimony from other impurities was analyzed using the theory of vacuum distillation, including saturation vapor pressure, molecular free path, and maximum volatilization rate. In the first step of vacuum distillation at 50 Pa and 630 ℃ for 60 min, zinc, sodium, and magnesium were volatilized to the gas phase, and their content were reduced to 0.17 ppm, 0.14 ppm, 0.13 ppm respectively, which meet the 5 N antimony standard. The content of arsenic was reduced to 1.21 ppm, while the antimony remains in the residue. In the second step of vacuum distillation at 1–10 Pa and 655 ℃ for 30 min, iron, lead, bismuth, manganese, copper, aluminum and gold were significantly reduced to 0.36 ppm, 0.35 ppm, 1.93 ppm, 0.05 ppm, 0.05 ppm, 0.12 ppm and 0.05 ppm, respectively, which meet the 5 N antimony standard, Therefore, the purity of volatile antimony obtained in the second step is 4 N8(99.998 wt%). This method provides reference for the preparation of high purity antimony.

Carbon Dioxide Flux and its Relationship to Water Quality in the Teluk Awur - Jepara, Indonesia

Abstract Anthropogenic activities on land will affect the carbon system in coastal waters. This condition will affect the role of coastal waters as a source or sink of carbon. This research will examine the distribution of carbonate systems and estimate CO2 fluxes. Water samples were taken at 30 stations as well as measuring in situ water parameters including pH, temperature, salinity, and pressure. Alkalinity was analysed based on the titration method, chl-a using the fluorometer method, and carbonate system parameters (pCO2(sea) and DIC) calculated using CO2SYS.xlsm. The pCO2(atm) value is calculated based on atmospheric data from satellite data, including the saturation vapour pressure of sea air in the atmosphere, fraction mol of CO2, and sea level pressure. Pearson correlation analysis was used to see the correlation between the measured parameters and CO2 flux. Carbon flux is determined based on the difference between atmospheric and oceanic pCO2. The DIC calculation result was in the range of 1,946.09 µmol/kg - 2,061.65 µmol/kg and the total alkalinity was 2,156.86 µmol/kg - 2,264.71 µmol/kg. Based on this value, Jepara coastal waters have pCO2(sea) of 573,800 micro-atmospheric (µatm) which is higher than pCO2(atm) (i.e., 386,772 µatm). The input of organic/inorganic carbon resulting from anthropogenic processes on land has influenced Jepara coastal waters which act as a source of CO2 into the atmosphere amounting to 103,799 mmol/m2/day. The results of this research can be used as a reference for managing coastal areas to achieve low carbon emissions.

Different model assumptions about plant hydraulics and photosynthetic temperature acclimation yield diverging implications for tropical forest gross primary production under warming

AbstractTropical forest photosynthesis can decline at high temperatures due to (1) biochemical responses to increasing temperature and (2) stomatal responses to increasing vapor pressure deficit (VPD), which is associated with increasing temperature. It is challenging to disentangle the influence of these two mechanisms on photosynthesis in observations, because temperature and VPD are tightly correlated in tropical forests. Nonetheless, quantifying the relative strength of these two mechanisms is essential for understanding how tropical gross primary production (GPP) will respond to climate change, because increasing atmospheric CO2 concentration may partially offset VPD‐driven stomatal responses, but is not expected to mitigate the effects of temperature‐driven biochemical responses. We used two terrestrial biosphere models to quantify how physiological process assumptions (photosynthetic temperature acclimation and plant hydraulic stress) and functional traits (e.g., maximum xylem conductivity) influence the relative strength of modeled temperature versus VPD effects on light‐saturated GPP at an Amazonian forest site, a seasonally dry tropical forest site, and an experimental tropical forest mesocosm. By simulating idealized climate change scenarios, we quantified the divergence in GPP predictions under model configurations with stronger VPD effects compared with stronger direct temperature effects. Assumptions consistent with stronger direct temperature effects resulted in larger GPP declines under warming, while assumptions consistent with stronger VPD effects resulted in more resilient GPP under warming. Our findings underscore the importance of quantifying the role of direct temperature and indirect VPD effects for projecting the resilience of tropical forests in the future, and demonstrate that the relative strength of temperature versus VPD effects in models is highly sensitive to plant functional parameters and structural assumptions about photosynthetic temperature acclimation and plant hydraulics.

Stomatal response to VPD in C4 plants with different biochemical sub-pathways.

C4 NAD-malic enzyme (NAD-ME) species occurs in drier regions and exhibit different drought responses compared to C4 NADP-malic enzyme (NADP-ME) species. However, a physiological mechanism explaining the geographical discrepancies remains uncertain. This study examined gas exchange patterns that might explain different distributions observed between two subtypes of C4 photosynthesis. We measured the response of leaf gas exchange to vapour pressure deficit (VPD) and CO2 in plants from six distinct C4 clades having closely related NAD-ME and NADP-ME species using a Li-Cor 6400 gas exchange system. We found that NAD-ME species exhibited greater relative reductions in stomatal conductance with increases in VPD than NADP-ME species but observed no consistent subtype differences in C4 cycle activity as indicated by the initial slope of the A response to intercellular CO2 concentration. Based on these results, we hypothesise the greater response of gs to increasing VPD may enable NAD-ME plants to outperform NADP-ME plants in hot, dry environments where VPD is normally high.

A practical method for the in-situ estimation of the effective thermal resistance of gas diffusion layers in PEMFC

The membrane electrode assembly of a PEM fuel cell is hotter than the gas feeding plates because heat is generated within it, and the diffusion layers are thermally resistive. The temperature gradient created, which increases as a function of the current density, is useful for evacuating the water produced in vapor form. This water transport mechanism is known as the “heat pipe effect”. The temperature gradient produces a saturation vapour pressure gradient, which in turn produces a diffusive vapor flow. Mastering water management, coupled with heat management, requires knowledge of the temperature of the MEA and therefore the effective thermal resistance of the diffusion layers. In this paper, we present an original method for estimating this thermal resistance in situ, without using heat flux sensors or directly measuring the temperature of the MEA. The method requires the ability to impose a temperature gradient between the anode and cathode plates, and to perform a hot-side water balance. Thermal resistance is deduced from the coupling between heat and water transfer. Two diffusion layers widely used by the community are tested. The GDL Sigracet 22 BB (from SGL Carbon) has a lower effective thermal resistance than the GDL Freudenberg H15C14. Variations in these thermal resistances are measured as a function of the temperature gradient imposed and of the compression ratio.

Downscaling Vapor Pressure Deficit across Complex Forested Terrain

Abstract The forest microclimate shapes many aspects of forest functioning, including plant regeneration and wildfire occurrence. In complex landscapes with varying terrain, the forest microclimate varies at fine spatial scales (10–100 m2). However, accurately mapping this variation remains challenging. Vapor pressure deficit (VPD) is an important microclimatic variable for plant growth and fire activity, yet few studies have specifically focused on downscaling VPD. The aim of this study was to examine the drivers of in-forest VPD in temperate eucalypt forests and develop a model to predict in-forest VPD. We use microclimate data from 37 in-forest weather stations, installed across an aridity gradient in southeastern Australia. We used linear mixed models within an information theoretic approach to develop a predictive model for daily maximum in-forest VPD using open VPD and topographic variables. The highest-ranked model included fundamental topographic drivers of vegetation structure and microclimate in forested landscapes: aspect, elevation, and slope, in addition to open VPD. The model had high accuracy when tested against independent data. We used this model to map fine-scale (30 m2, daily) maximum in-forest VPD across a topographically complex case study landscape. Predicted in-forest VPD showed considerable spatial and temporal variations not captured by coarse-scale open VPD. This represents a significant advancement in our ability to model microclimatic conditions in temperate eucalypt forests and has the potential to advance our understanding of how ecosystem processes vary at fine spatial scales.

Divergent Responses of Fir and Pine Trees to Increasing CO2 Levels in the Face of Climate Change

AbstractUnderstanding the response of forests to the increases in atmospheric CO2 (ca) is fundamental to implementing innovative management strategies and for assessing impacts on the global carbon and water cycles. Here, we explored correlations between ecophysiological traits and climate variability that influence changes in stable isotope carbon and oxygen (δ13C and δ18O) of tree‐rings. We present these relationships between species of the contrasting genera Abies and Pinus, along a latitudinal transect encompassing different biogeographical regions in North America. We also tested if the rate of intrinsic water‐use efficiency per unit of ca (dW/dca) during two periods (1890–1965 vs. 1966–2016), for fir and pine were different and indicated acclimation to ca increases. We hypothesize that, spatially and temporally, the divergent responses among species to carbon and oxygen isotopes and dW/dca are influenced by the site conditions and the historical increases in ca. From our results, we show that fir and pine species will behave physiologically different as global warming progresses. Firs are more responsive to atmosphere vapor pressure deficit along different geographical zones. The survival of forests species under climate change will rely on the response to water stress and species' traits that influence the regulation of dW. Finally, we want to highlight the concept of “progressive resource limitation” of soil water and nutrients, previously proposed by other authors, that likely indicate fir species that inhabit moister sites will benefit more from increased ca than pine, but this positive effect is likely transitory as global warming increases.

Influence of photosynthetic active radiation on sap flow dynamics across forest succession stages in Dinghushan subtropical forest ecosystem

With the intensification of global change, forests are subjected to varying degrees of drought or high-temperature stress, which has an indelible impact on the growth of trees. However, knowledge on the response of sap flow to environmental changes in different types of forests is still rare, especially in China's subtropical forest ecosystem. Consequently, studying how different tree species regulate their sap flow in response to shifting environmental conditions is essential for understanding forest transpiration, water use efficiency, and drought stress resilience. Therefore, this study aimed to investigate the sap flow dynamics of seven tree species in five forest plots, i.e., pine forest (PF), two types of mixed conifer-broadleaf forests (MF1+MF2), monsoon evergreen broadleaved forest (MEBF), and montane monsoonal evergreen broad-leaf forest (MOBF) at Dinghushan National Reserve in Southern China, using the heat dissipation probe technique and synchronous environmental factor recordings. Results demonstrated a significant influence of photosynthetic active radiation (PAR) on sap flow across all tree species, with mean PAR values ranging from over 1200 to 425 μmol m−2 s−1, establishing it as the principal driving factor. This observation underscores the heightened responsiveness or sensitivity of tree species to variations in PAR as the forest undergoes development and maturation. The correlation between vapor pressure deficit (VPD) and tree sap flow decreased as succession progressed. Moreover, the influence of soil water content (SWC) on sap flow stability against environmental changes increased. Similar patterns were also found between the two MF, with MF-2 displaying ecological characteristics and environmental conditions more closely aligned with those of the late-successional MEBF. The study reveals the intricate relationship between environmental factors and sap flow regulation in tree species within a subtropical forest ecosystem. Addressing a comparative gap in sap flow correlation among dominant tree species at Dinghushan, it establishes a hydro-physiological foundation for understanding tree species substitution during forest succession. The results provide key insights for forest management and climate-related research. Future studies should delve into the long-term implications of observed sap flow dynamics, exploring their impact on tree species adaptability amid ongoing environmental changes.

Deep removal of Sn, Pb, and Sb in refined indium by vacuum distillation

To deeply separate the azeotropic impurities from the refined indium, three novel processes of vacuum distillation by considering the variables of vacuum pressure, loading mass, distillation time, temperature, and the effective vacuum evaporation area are firstly presented. Thermodynamic calculations show that Pb, Sb and Sn can be separated from indium melt by vacuum distillation due to their great difference in saturated vapor pressure and separation coefficient. Experiments show that distillation at 800 ℃ for 7 h under a pressure of 10−3 Pa could achieve the Pb concentration of 0.004 ppm in indium melt by enlarging the evaporation area and small ratio of h1/h4. After 950 ℃ distillation, the concentrations of Sb and Sn in the condensing indium reduced respectively from 0.15 ppm to 0.009 ppm, and 8.1 ppm to 0.05 ppm. Multiple processes of vacuum distillation were used to achieve the 7 N purity of indium, with the removal ratio of over 99.5 %. Besides, it is found out that when the temperature dropped from 1075 ℃ to 780 ℃, the movement stroke of vapor atoms reduced from 509 mm to 209 mm.

The multidimensionality of plant drought stress: The relative importance of edaphic and atmospheric drought.

Drought threatens plant growth and related ecosystem services. The emergence of plant drought stress under edaphic drought is well studied, whilst the importance of atmospheric drought only recently gained momentum. Yet, little is known about the interaction and relative contribution of edaphic and atmospheric drought on the emergence of plant drought stress. We conducted a gradient experiment, fully crossing gravimetric water content (GWC: maximum water holding capacity-permanent wilting point) and vapour pressure deficit (VPD: 1-2.25 kPa) using five wheat varieties from three species (Triticum monococcum, T. durum & T. aestivum). We quantified the occurrence of plant drought stress on molecular (abscisic acid), cellular (stomatal conductance), organ (leaf water potential) and stand level (evapotranspiration). Plant drought stress increased with decreasing GWC across all organizational levels. This effect was magnified nonlinearly by VPD after passing a critical threshold of soil water availability. At around 20%GWC (soil matric potential 0.012 MPa), plants lost their ability to regulate leaf water potential via stomata regulation, followed by the emergence of hydraulic dysfunction. The emergence of plant drought stress is characterized by changing relative contributions of soil versus atmosphere and their non-linear interaction. This highly non-linear response is likely to abruptly alter plant-related ecosystem services in a drying world.