Evaporation Source Research Articles

Computational Fluid Dynamics Analysis of Temperature Distribution in Solar Distillation Panel with Various Flat Plate Materials

As the world population continues to grow, the demand for clean water is increasing daily, making it a crucial resource to access. However, there are ways to harness abundant resources like solar energy and seawater to produce clean water. The present studies have conducted experimental investigations to convert seawater into freshwater using solar stills, where solar energy is utilized as the primary heat source for evaporation. The temperature distribution inside the solar stills was analyzed using a flat plate made of three different materials: copper, stainless steel, and aluminum. To examine the temperature distribution and performance of the solar stills, researchers employed computational fluid dynamics simulations (Ansys R15.0). The results showed variations in temperature distribution among the three plate materials. Copper flat plates achieved the highest temperature, approximately 44.5 Celsius, followed by aluminum at 43.91 Celsius, while stainless steel exhibited the lowest temperature at around 42.01 Celsius. The average heat flux across the three materials was approximately 581 W/m2. Additionally, observations indicated that the amount of convection occurring in copper flat plates was 121.108 Watts; in aluminum, it was 118.517 Watts; and in stainless steel, it was 105.05 Watts. The radiation energy for stainless steel flat plates was 29.93 W; for copper, 16.14 W; and for aluminum, 13.49 W.

CloudRoots-Amazon22: Integrating Clouds with Photosynthesis by Crossing Scales

Abstract How are rain forest photosynthesis and turbulent fluxes influenced by clouds? To what extent are clouds affected by local processes driven by rain forest energy, water, and carbon fluxes? These interrelated questions were the main drivers of the intensive field experiment CloudRoots-Amazon22 which took place at the Amazon Tall Tower Observatory (ATTO)/Campina supersites in the Amazon rain forest during the dry season, in August 2022. CloudRoots-Amazon22 collected observational data to derive cause–effect relationships between processes occurring at the leaf level up to canopy scales in relation to the diurnal evolution of the clear-to-cloudy transition. First, we studied the impact of cloud and canopy radiation perturbations on the subdiurnal variability of stomatal conductance. Stoma opening is larger in the morning, modulated by the cloud optical thickness. Second, we combined 1-Hz frequency measurements of the stable isotopologues of carbon dioxide and water vapor with measurements of turbulence to determine carbon dioxide and water vapor sources and sinks within the canopy. Using scintillometer observations, we inferred 1-min sensible heat flux that responded within minutes to the cloud passages. Third, collocated profiles of state variables and greenhouse gases enabled us to determine the role of clouds in vertical transport. We then inferred, using canopy and upper-atmospheric observations and a parameterization, the cloud cover and cloud mass flux to establish causality between canopy and cloud processes. This shows the need for a comprehensive observational set to improve weather and climate model representations. Our findings contribute to advance our knowledge of the coupling between cloudy boundary layers and primary carbon productivity of the Amazon rain forest.

Primary and oxidative source analyses of consumed VOCs in the atmosphere

Consumed VOCs are the compounds that have reacted to form ozone and secondary organic aerosol (SOA) in the atmosphere. An approach that can apportion the contributions of primary sources and reactions to the consumed VOCs was developed in this study and applied to hourly VOCs data from June to August 2022 measured in Shijiazhuang, China. The results showed that petrochemical industries (36.9 % and 51.7 %) and oxidation formation (20.6 % and 35.6 %) provided the largest contributions to consumed VOCs and OVOCs during the study period, whereas natural gas (5.0 % and 7.6 %) and the mixed source of liquefied petroleum gas and solvent use (3.1 % and 4.2 %) had the relatively low contributions. Compared to the non-O3 pollution (NOP) period, the contributions of oxidation formation, petrochemical industries, and the mixed source of gas evaporation and vehicle emissions to the consumed VOCs during the O3 pollution (OP) period increased by 2.8, 3.8, and 9.3 times, respectively. The differences in contributions of liquified petroleum gas and solvent use, natural gas, and combustion sources to consumed VOCs between OP and NOP periods were relatively small. Transport of petrochemical industries emissions from the southeast to the study site was the primary consumed pathway for VOCs emitted from petrochemical industries.

Continuous stationary phase gradient preparation on planar chromatographic media using vapor phase deposition of silane

A new, versatile, and straightforward vapor phase deposition (VPD) approach was used to prepare continuous stationary phase gradients (cSPGs) on silica thin-layer chromatography (TLC) plates using phenyldimethylchlorosilane (PDCS) as a precursor. A mixture of paraffin oil and PDCS was placed at the bottom of an open-ended rectangular chamber, allowing the reactive silanes to evaporate and freely diffuse under a controlled atmosphere. As the volatile silane diffused across the length of the TLC plate, it reacted with the surface silanol groups thus functionalizing the surface in a gradient fashion. Characterization of the gradient TLC plates was done through UV visualization and diffuse reflectance spectroscopy (DRS). Visualizing the fluorescent gradient plates under UV radiation shows the clear presence of a gradient with the side closest to the vapor source undergoing the most modification. More quantitative characterization of the shape of the gradient was provided by DRS. The DRS showed that the degree of modification and shape of the gradient was dependent on the concentration of silane, VPD time, and relative humidity. To evaluate the chromatographic performance, a mixture of three aromatic compounds (acetaminophen (A), aspirin (As), and 3-hydroxy-2-naphthoic acid (3H)) was spotted on the high (GHP) and low phenyl (GLP) ends of the gradient TLC plates and the results compared to the separations carried out on unmodified and uniformly modified plates. The GHP TLC plates showed retention factors (Rf) of 0.060 ± 0.006, 0.391 ± 0.006, and 0.544 ± 0.006, whereas the unmodified plate displayed Rf values of 0.059 ± 0.006, 0.092 ± 0.003, and 0.037 ± 0.002 for the analytes A, As, and 3H, respectively. From the Rf values, it was observed that each modified plate exhibited different selectivity for the analytes. The GHP TLC plates exhibited better separation performance, and improved resolution compared to the GLP, unmodified, and uniformly modified plates. Overall, VPD is a new, cost-effective method for creating a gradient on the stationary phase which has the potential to advance chromatographic separation capabilities.

Dynamic and thermodynamic characteristics of warm-sector rainstorms caused by the southwest china vortex in sichuan basin

Using automatic rainfall station and ERA5 reanalysis data, the Southwest China vortex (SWCV) processes that induce warm-sector rainstorms in the Sichuan Basin were analyzed, their environmental field and dynamic thermal characteristics were researched through physical diagnosis and dynamic synthesis, and the development mechanism was discussed. The results showed that for the warm-sector rainstorms caused by the SWCV (SWCV-WR), the general circulation backgrounds can could be divided into three types: upper trough-vortex (Type I), plateau shear line (Type II), and short-wave trough (Type III) types. Regarding the aspects of the maintenance of the SWCV, duration of the warm-sector rainstorms, and maximum hourly precipitation intensity, the influence of Type I is the most evident, followed by Types II and III for SWCV-WR. The vertical structure of the SWCV is shallow and inclined to the west with height, but the positive vorticity of Types I and II can reach up to 200 hPa for SWCV-WR. The pseudo-equivalent potential temperature in the vortex area is greater than 354 K, which is accompanied by an upward-energy tongue, and shallow secondary circulation occurs on the eastern side of the SWCV, promoting vortex development. Regarding the thermodynamic characteristics of SWCV, Type I is the strongest, followed by Type III, and Type II is the weakest. The water vapor supply in different types of SWCV-WR is not only closely related to the strength of water vapor transport in the Bay of Bengal, but also to the variations in water vapor transport caused by the influence of different water vapor sources, such as the South China Sea and western Pacific Ocean, during its transportation. For SWCV-WR, the vorticity advection presents an uneven east-west positive and negative distribution. Under the dynamic forcing, the positive vorticity on the east side of SWCV of Types I and II (III) is enhanced (weakened), while that on the west side is weakened (enhanced). Different atmospheric vorticity variations have different significant effects on the three types of SWCV-WR. Under the spatial non-uniform heating, the horizontal non-uniform heating effect on the different types of SWCV-WR has regional differences, while the vertical non-uniform heating effect has the largest effect on the spatial non-uniform heating and a positive heating effect on the three types of SWCV-WR. Therefore, the spatial non-adiabatic heating effect, particularly the vertical non-uniform heating effect, is an important mechanism for the development and evolution of SWCV and SWCV-WR.

Influence of the distance between evaporation source and substrate on formation of lead telluride (PbTe) nanostructures by vacuum thermal evaporation method

Lead telluride nanostructures were obtained on silicon substrates by thermal evaporation in vacuum. Growth occurred at three different distances between the evaporation source and the substrate. The distances between the evaporator and the evaporation source were 5 cm; 7.5 cm and 10 cm. Structural characteristics were studied using XRD, SEM, EDX, AFM analyses. These methods provided information about the crystal structure, morphology, microstructure and elemental composition of the material. X-ray diffraction analysis showed that thin films of lead telluride obtained by thermal evaporation in vacuum have a cubic crystal structure. This experimental work was carried out to determine the effect of distance on the structure of lead telluride (PbTe). During the experiment, the optimal modes for the formation of lead telluride (PbTe) nanostructures were determined, which was equal to d = 10 cm. It was found that lead telluride (PbTe) nanostructures are formed at this distance.

The Complexity of Moisture Sources Affects the Altitude Effect of Stable Isotopes of Precipitation in Inland Mountainous Regions

AbstractFrom a global perspective, the stable isotope altitude effect is crucial for understanding climate information. However, the intensity of this effect can be influenced by the source of moisture, particularly in inland mountainous regions where the moisture sources are complex. Different combinations of moisture sources might affect the altitude effect. Focusing on the upper Shiyang River in the northern part of the Qilian Mountains in China, this study calculated the proportion of recycled moisture in precipitation and utilized the HYSPLIT model to determine the source of advective moisture. It explored the characteristics and mechanisms by which moisture sources affect the spatiotemporal variations in precipitation isotope effects within the study area. The findings indicated that: (a) The altitude effect follows a seasonal pattern: winter < autumn < spring < summer, with a reverse effect in winter. (b) As the contribution of recycled moisture to precipitation increases, the altitude effect of stable isotopes weakens, primarily due to the disruptive influence of recycled moisture on this effect. (c) The altitude effect of stable isotopes in precipitation is determined by the direction of the moisture source and its attributes. When the primary source of advective moisture runs perpendicular to the mountain range and the moisture migration speed is slow, the altitude effect is pronounced. Thus, although temperature directly causes the altitude effect, water vapor sources significantly influence it in inland mountainous regions.

Southern Ocean drives multidecadal atmospheric CO2 rise during Heinrich Stadials

The last glacial period was punctuated by cold intervals in the North Atlantic region that culminated in extensive iceberg discharge events. These cold intervals, known as Heinrich Stadials, are associated with abrupt climate shifts worldwide. Here, we present CO2 measurements from the West Antarctic Ice Sheet Divide ice core across Heinrich Stadials 2 to 5 at decadal-scale resolution. Our results reveal multi-decadal-scale jumps in atmospheric CO2 concentrations within each Heinrich Stadial. The largest magnitude of change (14.0 ± 0.8 ppm within 55 ± 10 y) occurred during Heinrich Stadial 4. Abrupt rises in atmospheric CO2 are concurrent with jumps in atmospheric CH4 and abrupt changes in the water isotopologs in multiple Antarctic ice cores, the latter of which suggest rapid warming of both Antarctica and Southern Ocean vapor source regions. The synchroneity of these rapid shifts points to wind-driven upwelling of relatively warm, carbon-rich waters in the Southern Ocean, likely linked to a poleward intensification of the Southern Hemisphere westerly winds. Using an isotope-enabled atmospheric circulation model, we show that observed changes in Antarctic water isotopologs can be explained by abrupt and widespread Southern Ocean warming. Our work presents evidence for a multi-decadal- to century-scale response of the Southern Ocean to changes in atmospheric circulation, demonstrating the potential for dynamic changes in Southern Ocean biogeochemistry and circulation on human timescales. Furthermore, it suggests that anthropogenic CO2 uptake in the Southern Ocean may weaken with poleward strengthening westerlies today and into the future.

Marine Stratus—A Boundary-Layer Model

A relatively simple 1D RANS model of the time evolution of the planetary boundary layer is extended to include water vapor and cloud droplets plus transfers between them. Radiative fluxes and flux divergence are also included. An underlying ocean surface is treated as a source of water vapor and as a sink for cloud or fog droplets. With a constant sea surface temperature and a steady wind, initially dry or relatively dry air will moisten, starting at the surface. Turbulent boundary layer mixing will then lead towards a layer with a well-mixed potential temperature (and so temperature decreasing with height) and well-mixed water vapor mixing ratio. As a result, the air will, sooner or later, become saturated at some level, and a stratus cloud will form.

The investigation of retrieval method for aerosol and water vapor profiles based on MAX-DOAS technology

Simultaneously obtaining the vertical distribution and profile of aerosol and water vapor is crucial for in-depth understanding of the Earth's radiation balance, regional water cycle, and the causes of frequent haze weather in China. This study developed a system and inversion method based on multi-axis differential optical absorption spectroscopy (MAX-DOAS) to simultaneously retrieve tropospheric aerosol and water vapor profiles. The absorption of dioxy (O4) was obtained by multi-elevation measurement using the developed ground-based MAX-DOAS system. By minimizing a cost function combining an atmospheric radiative transfer model, aerosol extinction profiles were first inverted, followed by water vapor profiles. Optimized parameter selection in the look-up table method reduced reliance on prior profile information, enhancing pollutant distribution retrieval accuracy. In the monitoring period in Huaibei region, aerosols were mainly below 1.5 km, while water vapor concentrations decreased with altitude. Comparisons of water vapor vertical column densities (VCDs) retrieved through the look-up table method with the European Centre for Medium-Range Weather Forecasts(ECMWF) ERA5 model and geometric approximation showed good agreement, with correlation coefficients of 0.93 and 0.98, respectively. To comprehend water vapor sources at various vertical layers, a 24-h backward trajectory clustering analysis was conducted using the HYSPLIT model based on observed wind fields. Findings revealed that at 500 m altitude, water vapor primarily emanated from the southeast, whereas at 1 km and 2 km altitudes, it predominantly originated from the southwest. The study advances simultaneous tropospheric aerosol and water vapor profile retrieval, providing reliable technical support for the investigation of regional pollution.

Axial Phenoxylation of Aluminum Phthalocyanines for Improved Cannabinoid Sensitivity in OTFT Sensors.

Cannabis producers, consumers, and regulators need fast, accurate, point-of-use sensors to detect Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) from both liquid and vapor source samples, and phthalocyanine-based organic thin-film transistors (OTFTs) provide a cost-effective solution. Chloro aluminum phthalocyanine (Cl-AlPc) has emerged as a promising material due to its unique coordinating interactions with cannabinoids, allowing for superior sensitivity. This work explores the molecular engineering of AlPc to tune and enhance these interactions, where a series of novel phenxoylated R-AlPcs are synthesized and integrated into OTFTs, which are then exposed to THC and CBD solution and vapor samples. While the R-AlPc substituted molecules have a comparable baseline device performance to Cl-AlPc, their new crystal structures and weakened intermolecular interactions increase sensitivity to THC. Grazing-incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) are used to investigate this film restructuring, where a significant shift in the crystal structure, grain size, and film roughness is detected for the R-AlPc molecules that do not occur with Cl-AlPc. This significant crystal reorganization and film restructuring are the driving force behind the improved sensitivity to cannabinoids relative to Cl-AlPc and demonstrate that analyte-semiconductor interactions can be enhanced through chemical modification to create more responsive OTFT sensors.

Temporal variability of the isotope compositions of plum rain in Nanjing from event to interannual time scales

Precipitation in the plum rain period accounts for 40%-50% of annual precipitation in the monsoon region. To clarify the temporal variability of the isotopic composition of precipitation during the plum rain period from event to interannual time scale and identify the influencing factors, we analyzed the isotopic composition of precipitation and its influencing factors in Nanjing from 2015 to 2022. By using the Hybrid Single-particle Lagran-gian Integrated Trajectory (HYSPLIT) model with specific humidity analysis, we investigated the water vapor source and influencing factors. The results showed that 1) the isotopic abundance of atmospheric precipitation was depleted in the summer and enriched in winter. dx was lower in summer and higher in winter. The isotopic abundance of precipitation from the plum rain was depleted compared to mean value of the whole-year. 2) There was no significant correlation between δ2H and δ18O of the plum rain (precipitation) with local meteorological factors. However, dx was lower in light rain, reflecting the effect of sub-cloud evaporation. The average dx was higher during plum rain period in years with more total plum rain precipitation. 3) The low-latitude South China Sea and the western Pacific Ocean source area provided water vapor for the plum rain. The shift of moisture source region led to abrupt changes in precipitation isotopes. Our results could provide data support for studies on precipitation isotopes in the monsoon region, as well as a reference point for further understanding the precipitation mechanism of the plum rain and stu-dying the seasonal variability of atmospheric circulation in the East Asian monsoon region.

Dynamic characteristics of refrigerant evaporation temperature in air-water heat source heat pump

In order to improve the problem of reduced heat capacity and unstable heating ability of air source heat pump (ASHP) in the heating mode during the cold season, a heat pump evaporator using air and surface water as a heat source is designed in this paper. A heat transfer unit's calculation model of an air–water heat source evaporator is established. Experimental tests and simulation studies are conducted on the refrigerant evaporation temperature and heat pump heating performance. On this basis, a refrigerant evaporation temperature prediction model is constructed using a multiple linear regression (MLR) model. The trend of refrigerant evaporation temperature under air–water heat source is analyzed by taking the winter meteorological parameters in Xiangtan City as an example. The results show that the air–water heat source heat pump (A-WSHP) has a higher refrigerant evaporation temperature and a smaller temperature fluctuation range than the ASHP. The average values of refrigerant evaporation temperatures under the experimental conditions were 5.3 °C and 4.6 °C, respectively. The temperature fluctuation ranges were 3.8 °C-6.7 °C and 2.8 °C-7.0 °C, respectively. The A-WSHP has higher heating capacity and heating stability. Air temperature, air velocity, water spray temperature and water spray flow rate are all important parameters that affect the refrigerant evaporation temperature of a heat pump. Evaporation temperature changes are positively correlated with these factors. In the refrigerant evaporation temperature prediction model, the air temperature change has the most significant effect on the evaporation temperature, followed by spray water temperature, air velocity, and spray flow rate, whose influence weights are 82.5 %, 38.8 %, 29.4 %, and 25.3 %, respectively. Selecting different temperatures of spray water and adjusting the evaporator's inlet spray flow rate can improve the refrigerant evaporation temperature and heat pump heating stability.

Fabrication of 197Au-backed Silicon target for In-beam Gamma-ray spectroscopy experiment

The fabrication of stable 197Au-backed natural Si targets with a thickness ranging from ∼ 400 μg/cm2 to ∼ 1.1 mg/cm2 using an electron beam evaporation technique is discussed. In one of the attempts, a graphite sheet was used as an evaporation source, which proves to be an efficient method in terms of minimal wastage of source material. Characterizations of the fabricated targets using various technique revealed that the targets were uniform in thickness and had negligible contamination. The optimization of evaporation parameters in the present work enhances the potential for future fabrication of isotopically enriched Si targets.

Dipole Pattern of Holocene Hydroclimate Variations Across the Asian Drylands: Critical Evidence From West Asia

AbstractExploring the spatiotemporal differences of hydroclimate variations is crucial for managing future climate change. In the Asian drylands, West Asia (WA) and arid central Asia (ACA) are both climatically dominated by the westerlies and have shown a dipole pattern in precipitation variation during the past several decades. However, it is unclear whether such a difference exists during the Holocene, mainly because the dispute between the δ18O‐based early Holocene hydroclimate optimum and the pollen‐based mid‐Holocene optimum in WA. Here we present a precisely dated record based on lipid biomarkers from Almalou Peatland in the western Iranian Plateau. The chain length of n‐alkanoic acids was interpreted as a hydroclimate indicator based on a proxy validation study. Our record reveals a wetting trend during 9–7.5 cal ka BP, a mid‐Holocene hydroclimate optimum (7.5–3 cal ka BP), and a rapidly drying trend during 3–0 cal ka BP. The hydroclimate variation was supported by a water‐level reconstruction from the same core. The most negative δ18O values during the early Holocene could be partly attributed to the impacts of water vapor sources. Comparing our reconstruction from WA to those from ACA, we found a dipole pattern of hydroclimate variations on the millennial timescale during the Holocene. The simulation results revealed that, unlike the persistent wetting trend in ACA, the pivotal shift of spring insolation led to a transition from wetting to drying conditions in WA, ultimately leading to the generation of dipole pattern. This demonstrates that despite the consistent control by westerlies over the Asian drylands, there are distinct spatial differences in hydroclimate responses to natural forcings.

Integrating paleolimnological hydrogen and oxygen isotope records during the Holocene on the Tibetan Plateau

Stable isotopes are effective proxy indicators for past climate and environment changes. Paleolimnological hydrogen and oxygen isotopes have been used to reconstruct changes in precipitation isotopes and continental climates. However, the stable hydrogen and oxygen isotope records from lakes are rarely compared and integrated directly to study past changes in climate and environment due to their different fractionation pathways. Combined studies on hydrogen and oxygen isotopes would provide much more information than single isotope records. Here, we reanalyzed published lacustrine hydrogen and oxygen isotope records across the Tibetan Plateau, to investigate how both isotope records reveal the influences of the Indian summer monsoon and the westerlies on the Plateau throughout the Holocene. Principal component analysis (PCA) shows that the first principal component (PC1) of 16 lacustrine hydrogen isotope records resembles that of 28 oxygen isotope records. The PC1s of the hydrogen and oxygen isotope records were generally low at 12–6 ka BP, followed by gradual increase since 6 ka BP, suggesting the influence of the Indian summer monsoon. Reconstruction of Holocene precipitation isotopes showed that the slopes of segmented precipitation isotope lines generally followed changes in monsoon intensity. The PC2s for hydrogen and oxygen isotope records remained relatively low at ∼8–4 ka BP, coinciding with moisture variation in westerlies dominated regions. The millennial-scale variations in both hydrogen and oxygen isotope records, revealed by the PC3-PC6, likely responded to the ice drift events in the North Atlantic Ocean, as well as differences in the isotope fractionation pathways at specific sites. The reanalysis of stable hydrogen and oxygen records across the Tibetan Plateau suggests that the water vapor source is the most important factor affecting the isotope variation, though the isotopic fractionation processes may differ significantly. Our results revealed nonlinear variations of monsoon and westerlies on the Tibetan Plateau during the Holocene. This review shows that integration of the stable hydrogen and oxygen isotope records would provide comprehensive understanding of the atmospheric circulation on the Tibetan Plateau.

Sources, gas-particle distribution and health risks of atmospheric PAHs in two typical basin cities in China

The sources of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of various cities are highly intricate. Conducting research on the pollution characteristics of different types of PAHs in cities will help to focus on solving air pollution problems based on urban characteristics. Polycyclic aromatic hydrocarbons (PAHs) in the PM2.5-bound state and gas-phase were analyzed in the winter atmosphere of Yuncheng and Nanyang, China, to determine their pollution and spatial characteristics. The results revealed that in Yuncheng, the average concentrations of these 16 PAHs were 129.83 ± 96.63 ng m−3 in the PM2.5-bound form and 168.05 ± 88.64 ng m−3 in the gas phase, surpassing those observed in Nanyang, where the averages were 66.53 ± 32.49 ng m−3 and 112.80 ± 65.90 ng m−3 for particulate and gas phases, respectively. Gaseous samples primarily contained low molecular weight PAHs, while medium and high molecular weight PAHs were more prevalent in particulate samples. The linear relationship between the gas-particle partition coefficient (logKP) and the gas partition coefficient (PL0) and KOA value of PAHs in both cities suggested that during winter, PAHs in Yuncheng and Nanyang predominantly adsorb onto particles, failing to achieve gas-particle equilibrium. Source analysis using positive matrix factorization (PMF) identified coal combustion (26.4%–41.9%), biomass combustion (26.3%–29.6%), motor vehicle emissions (16.3%–30.4%), and evaporation sources (15.8%–26.9%) as the primary sources of atmospheric PAHs in both cities. Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) analyses indicated that pollutants originating from the northwest direction and near-earth air masses exerted a substantial influence on both cities. According to health risk assessments, both Yuncheng City and Nanyang City exhibited a certain risk of cancer due to atmospheric PAH exposure. However, the risk of cancer was higher in Yuncheng City compared to Nanyang City. The research results uncover the pollution characteristics and primary sources of polycyclic aromatic hydrocarbons (PAHs) in different types of urban air. It emphasizes the substantial contribution of local pollution sources to atmospheric PAHs and emphasizes the necessity of prioritizing control measures.

Potassium and sodium vapor diffusion pump development for fusion system

An alkali metal diffusion pump, which can meet many requirements for DT fusion system, was developed based on a commercial oil diffusion pump. Using sodium, potassium, and oil each as a vapor source, their evacuation behaviors were compared. The evacuation rate using potassium was comparable to that by original oil, and operation using sodium was found to require higher temperature. The compression ratio and evacuation of deuterium were also investigated. The diffusion pumping system was operated successfully, making this type of evacuation system a potential candidate for the fusion system.

Towards an Improved Understanding of the Evolution of the Size Distribution of Ultrafine Nanoparticles Produced by a Rapidly Quenched Vapor Source

Towards an Improved Understanding of the Evolution of the Size Distribution of Ultrafine Nanoparticles Produced by a Rapidly Quenched Vapor Source

The Arabian Sea and Bay of Bengal play a key role in extreme precipitation during the snow season over the Tibetan Plateau

AbstractWater vapour is a critical component of the hydrological cycle and plays a key role in climate systems and water resources on the Tibetan Plateau (TP). However, the effect of water vapour on extreme precipitation during the snow season over the TP, where snow cover is widespread, has not been determined. In this study, we investigated the water vapour contributions from extreme precipitation events during the snow season from 1980 to 2017 in four subregions of the TP using the flexible particle dispersion method. We divided the TP into four regions: the northeastern TP (NETP), northwestern TP (NWTP), southeastern TP (SETP) and southwestern TP (SWTP). The water vapour contributions from extreme precipitation among the four subregions were clearly different. The most important water vapour area that contributed the most water vapour to extreme precipitation over the NETP was from local contributions; nevertheless, Central Asia contributed the most water vapour to the NWTP. Water vapour from the Arabian Sea and Bay of Bengal (ASBB) dominantly controlled extreme precipitation in the SETP at a ratio of 45% and in the SWTP at a ratio of 72.9%. The water vapour contribution from the ASBB was significantly correlated with the extreme precipitation occurring in the TP subregions during the snow season in comparison to that of non‐extreme precipitation. These results could improve the understanding of water vapour cycle differences across the interior TP; additionally, our study provides a theoretical reference for the relationship between the snow distribution and water vapour sources in the TP.