Search

[Display omitted] Aerosols greatly influence precipitation characteristics, thereby impacting the regional climate and human life. As an indispensable factor for cloud formation and a critical radiation budget regulator, aerosols can affect precipitation intensity, frequency, geographical distribution, area, and time. However, discrepancies exist among current studies due to aerosol properties, precipitation types, the vertical location of aerosols and meteorological conditions. The development of technology has driven advances in current research, but understanding the aerosol effects on precipitation remain complex and challenging. This paper revolves around the following topics from the two perspectives of Aerosol-Radiation Interaction (ARI) and Aerosol-Cloud Interaction (ACI): (1) the influence of different vertical locations of absorbing/scattering aerosols on the atmospheric thermal structure; (2) the fundamental theories of ARI reducing surface wind speed, redistributing water vapour and energy, and then modulating precipitation intensity; (3) different aerosol types (absorbing versus scattering) and aerosol concentrations causing different precipitation diurnal and weekly variations; (4) microphysical processes (cloud water competition, invigoration effect, and evaporation cooling) and observational evidence of different effects of aerosols on precipitation intensity, including enhancing, inhibiting, and transitional effects from enhancement to suppression; and (5) how meteorology, water vapor and dynamics influencing the effect of ACI and ARI on precipitation. In addition, this review lists the existing issues and future research directions for attaining a more comprehensive understanding of aerosol effects on precipitation. Overall, this review advances our understanding of aerosol effects on precipitation and could guide the improvement of weather and climate models to predict complex aerosol-precipitation interactions more accurately. [ABSTRACT FROM AUTHOR]

This paper investigated the microstructure and mechanical properties of AISI 430 ferritic stainless steel (FSS) after annealing in either the single-phase or two-phase region, followed by different cooling manners: water cooling, air cooling and furnace cooling. After annealing at 840 °C in the single-phase region, the sample consisted primarily of ferrite, with M 23 C 6 and M 2 (C, N) precipitates aligned mainly along the rolling direction (RD). For the water-cooled and air-cooled samples annealed at 950 °C in the double-phase region, they formed a dual-phase structure comprising ferrite and martensite, with precipitations primarily located within the martensite lath. Conversely, the sample subjected to annealing at 950 °C followed by furnace cooling displayed a single ferrite structure, owing to the decomposition of austenite. In this case, the precipitations were mainly found along the grain boundaries, with some also forming within the ferrite grain. The paper delved into the analysis of mechanical properties and strengthening mechanism through tensile experiments and fracture morphology examination. The influence of heating range and cooling manner on the yield characteristics of FSS was discussed. The results indicated that the air-cooled and furnace-cooled samples annealed at 840 °C displayed a clear yield platform in their tensile curves. Conversely, the samples treated with other heat treatments exhibited continuous yielding or no obvious yield platform. This difference may be attributed to the influence of heating temperature range and cooling manner on the distribution of dislocations and interstitial atoms within the ferrite grains. [ABSTRACT FROM AUTHOR]

As one of the new research direction of the fourth generation cladding material, the interface strength of SiC f /SiC-Zr and the sustain properties of Zr alloy is the key point of the research. The study utilizes the third generation SiC fiber to form the 2.5D wave structure among the outside layer of Zr alloy tube and prepare the SiC f /SiC-Zr composite material cladding tube with PyC interface through PIP. Then the boundary adhesion properties as well as the influence of PIP on the Zr alloy tube are studied in the paper. The results show that SiC f /SiC-Zr composite cladding has the density of 3.73 ∼ 3.95 g/cm3, air tightness of 9.82 × 10–10 Pa·m3/s and boundary adhesion of 80 N/mm. With the increase cycle time of PIP process, the grain grow gradually into columnar grain appearing segregation and bad effect phase and micro crack. All of this will lead to the brittleness of Zr alloy. The degradation of SiC f /SiC-Zr physical properties is due to the shrink of micro defects and the failure of Zr alloy tube. [ABSTRACT FROM AUTHOR]

Fluoride is a common pollutant from nature, normal life, and production. Adsorption, electro-adsorption, and precipitation are dominant mechanisms corresponding to the adsorption and electro-adsorption technologies for removing fluoride. This paper presents Ti 3 AlC 2 as an effective reagent for removing fluoride under acidic conditions. The adsorption mechanisms of adsorption and electro-adsorption were compared to sedimentation at pH 2 and 1, leading to a higher removal rate of adsorption by pH 2 than at pH 1. The adsorptive behavior of Ti 3 AlC 2 with fluoride includes both multilayer sorption and chemisorption. Furthermore, the precipitation reaction induced a partial change of Ti 3 AlC 2 to MXene. Notably, electro-adsorption was more effective rather than sedimentation at pH 1 in capacitive deionization technology. The Al adsorption sites made it easier to combine fluoride than Ti, and aluminum fluoride was easier to produce than titanium (III) fluoride. These adsorption and electro-adsorption experiments were carried out to elucidate and delineate the performance of Ti 3 AlC 2 for removing fluoride. A molecular model of Ti 3 AlC 2 was also built to calculate adsorption using the density functional theory. Hence, the Ti 3 AlC 2 molecular model combined with XPS and other characterizations of materials provided an effective, easy-to-understand combinative mechanism for removing fluoride. [Display omitted] • Ti 3 AlC 2 was applied to remove fluoride. • The removal of fluoride was investigated by comparison of adsorption and electro-adsorption. • Different ratios of reaction mechanisms were analyzed by adsorption and electro-adsorption. • The reaction mechanisms were studied by combining experiments and density functional theory. [ABSTRACT FROM AUTHOR]

Precipitation hardening provides a great potential to achieve superior strength-ductility trade-off in high-entropy alloys (HEAs). However, the formation of some precipitates such as brittle sigma phases may significantly deteriorate the ductility. Empirical criteria such as PSFE, VEC, and M d were proposed to predict the formation of undesirable phases during aging, nevertheless, they are insufficient to describe their stability and are not dependable for the noted purpose. Accordingly, for the first time, machine-learning models were conducted for this prediction. A feature selection based on Pearson correlation and mutual information has been used to improve the performance of models. Linear regression, second-order polynomial regression, decision tree, and neural network are conducted by machine learning methods in this paper. Among the implemented methods, the neural network had the best performance which improved the accuracy of the prediction by ∼20% compared to the conventional methods. Additionally, a new parameter based on linear regression, which is more reliable and user-friendly than thermodynamic parameters was developed in this investigation. The results showed that some elements such as Cr, Mo, and V may promote sigma precipitation. A HEA with a sigma-free microstructure was developed for validation of the model. We strongly believe that this HEA has a great potential for overcoming the strength-ductility trade-off because of not only the lack of sigma precipitate but also the presence of NiAl precipitate. The results are a step forward in designing alloys with the potential of microstructure engineering to achieve superior properties. • Sigma phase formation was predicted by machine learning (ML) models in high-entropy alloys. • The ML models provide higher average accuracy compared to empirical criteria for predicting sigma phase formation. • Cr, Mo, and V play key role on stabilization of the sigma phase in the microstructure based on model. • A novel Co 30 Ni 25 Mn 30 Cr 10 Al 5 (at. %) HEA was developed to assess the applicability and validity of the ML model. [ABSTRACT FROM AUTHOR]

Re doping is an essential way to improve the high temperature mechanical properties of nickel-based single crystal superalloy (NBSCS). However, how the doped Re affects the mechanical properties of NBSCS is still unclear, and a quantitative description is lacking. This paper attempts to study the influence of Re doping on plastic deformation mechanisms of NBSCS at atomic scale. First, the grand-canonical Monte Carlo method was employed to determine the distribution of Re atoms within the two-phase microstructure of NBSCS. Then, the molecular dynamics simulations were carried out to study the effect of Re doping on the dislocation motion and evolution during plastic deformation, with a focus on two important deformation mechanisms in NBSCS, i.e., dislocation gliding in the hairpin-like shape in the narrow γ matrix channel and dislocation cutting into the γ′ precipitation from the γ matrix. The results show that Re atoms prefer to segregate at the γ/γ′ interface. The increase of Re concentration in NBSCS can significantly improve both the critical stress of dislocations gliding in the γ matrix channel and the critical stress of dislocation cutting into the γ′ precipitation. These simulation results are qualitatively consistent with experimental observations. Based on these atomic scale simulations, two quantitative models for screw dislocation gliding in a hairpin-like shape in the γ matrix channel and dislocation cutting into the γ′ precipitation in the super-dislocation pair that take into account the Re doping effects have been proposed. The good agreement between the molecular dynamics simulation and the model prediction suggests that these quantitative models can be used for up-scale simulations of the dislocation movement and evolution in the presence of Re doping in NBSCS. • Re segregation near the γ/γ′ interface was obtained by GCMC calculation. • The critical stresses for leading dislocation cutting into the γ′ precipitation and dislocation gliding in a hairpin-like shape in γ matrix both increase with the increasing Re concentration. • Two theoretical models were proposed to describe the critical stresses of the dislocation mechanisms. [ABSTRACT FROM AUTHOR]

• Significantly changes of LAI and GPP mostly occurred in eastern and southern China. • Divergence between LAI and GPP were found in regions with dense vegetation coverage. • The importance of VPD, SM, and PT to vegetation indices increased as latitude decreases. Climate change notably boosts terrestrial hydraulic redistribution pattern, which could directly affect the spatiotemporal evolution characteristics of vegetation productivity. However, the spatiotemporal evolution pattern of long-term hydrometeorological controls of vegetation productivity is still not fully understood. This paper comprehensively explored the impacts of hydrometeorological controls on leaf area index (LAI) and gross primary productivity (GPP) in China during 1982–2015 using both satellite observations and reanalysis. Vapor pressure deficit (VPD), evapotranspiration (ET), precipitation (PT), and soil moisture (SM) were used as representative indicators during investigation. The dynamics of LAI and GPP displayed increasing trends on the whole. And significantly changes mostly occurred in eastern and southern China, accompanied by moderate to dense vegetation coverage. An accelerated increasing trend for LAI could be observed since September 2003 (+0.175 per decade), while the growth rate of GPP (+16.76 g C/m2 per decade) basically maintained stable. In terms of hydrometeorological controls, VPD and ET showed consistently increasing trend and SM presented falling trend in the context of warming climate. Through analysis of feature importance index established by Random Forest, the importance of VPD, SM, and PT obviously increased as latitude decreases, which implied the high sensitivity of vegetation in semi-humid\humid regions to water availability. Additionally, divergence between LAI and GPP can be found in southern Tibet Plateau region and coastal regions, which provides compelling evidence that in the case of high LAI, increasing LAI could weaken the improvement effect on GPP. Findings of this study is expected to promote the understanding of long-term vegetation responses to hydrometeorological variations. [ABSTRACT FROM AUTHOR]

In drought studies based on tree-ring data, there is currently no unified drought index that can capture the drought signals contained in tree rings from different climates, habitats, and species. This makes it difficult to compare the results of numerous studies. This paper compared data charactering wet and dry variations in the Ulan Buh Desert in northwestern China from 1962 to 2017, as indicated by different drought indices. We selected the most commonly used drought indices in tree-ring research: precipitation (Pre), self-calibrating Palmer aridity index (scPDSI), and standardized precipitation evapotranspiration index (SPEI), based on observed meteorological data (-obs) and grid data from the Climatic Research Unit (-cru). The results showed that although the different drought indices were significantly correlated with each other, they showed different linear trends. Correlation analyses with the tree-ring width chronology in the study area showed that the applicability of drought indices based on observed data was better than that of drought indices based on CRU data. The correlation between SPEI-cru and chronology was much lower than that of SPEI-obs, scPDSI-obs, scPDSI-cru, Pre-obs and Pre-cru. The extreme drought years identified by SPEI-cru also differed from other indices. These results suggest that SPEI-cru is not applicable to dendrochronological studies in the Ulan Buh Desert, mainly due to the differences between the CRU data and the measured data, and the high sensitivity of SPEI to potential evapotranspiration. This case study illustrates that tree-ring based drought studies must be based on an assessment of the applicability of different drought indices. [Display omitted] • Different drought indices show different variations. • SPEI-cru is not applicable to dendrochronological studies in the Ulan Buh Desert. • Evaluation of the applicability of drought indices is necessary in dendrochronological studies. [ABSTRACT FROM AUTHOR]

• A spatial random forest-based downscaling and merging method (SRF-DM) is proposed. • SRF-DM performs better than the original satellite-based precipitation products. • SRF-DM is more accurate than the classical machine learning-based methods. • Spatial autocorrelation is the most important variable. • SRF-DM has a good performance even when the gauge density is low. Publicly available satellite precipitation products (SPPs) are essential inputs for hydrological models. However, the existing SPPs suffer from coarse resolutions and large uncertainties, which greatly hinder their widespread applications. Thus, to fully utilize the unique characteristics of each individual SPP, a spatial random forest (SRF)-based downscaling and merging (SRF-DM) method is proposed to fuse multiple SPPs and gauge observations in this paper. The proposed method incorporates spatial autocorrelation information between precipitation observations through a covariate. This covariate is estimated using ordinary kriging interpolation on spatial neighbors that have a high correlation with the target location. The proposed method was used to generate 1-km daily precipitation data using the datasets from five satellite precipitation products (IMERG, GSMaP, CHIRPS, MORPH, and PERSIANN) and gauge observations in the period from January 1, 2015 to December 31, 2019 over Sichuan province, China. The performance of SRF-DM was compared with the original SPPs, XGBoost-based downscaling and merging (XGB-DM), two double-layer machine learning (ML) methods, namely RF-RF and RF-artificial neural network (RF-ANN), and three single ML methods, namely RF, ANN, and RF-based Merging Procedure (RF-MEP). The experimental results demonstrate the following findings: (i) SRF-DM is more accurate than the original SPPs across different temporal scales (i.e., daily, monthly, and seasonal) in terms of statistical and categorical accuracy measures, (ii) SRF-DM outperforms the six ML-based methods in estimating high precipitation and capturing spatial precipitation patterns, (iii) the spatial autocorrelation between neighboring precipitation data is the most significant factor in both downscaling and merging, and (iv) the performance of SRF-DM is influenced by gauge density, but it still yields good results even with a limited number of gauges. On the whole, SRF-DM is considered an effective tool for generating daily precipitation products with high accuracy and resolution, which is primarily attributed to its satisfactory performance in regions with diverse precipitation patterns and topography. [ABSTRACT FROM AUTHOR]

• Irrigation changes precipitation. • Increased irrigation produces shallower planetary boundary layer. • Increased irrigation increases latent heat flux and reduces sensible heat flux. • Increased irrigation increases equivalent temperature and reduces air temperature. Land use land cover change, including irrigation, impacts weather and climate. In this paper a precipitation event that occurred on the morning of 23 July 2018 during the Great Plains Irrigation Experiment (GRAINEX) is investigated. Six Weather and Research Forecasting (WRF) model-based experiments were conducted, which involved the increase or decrease of soil moisture by 5 % and up to 15 % over the irrigated croplands. These changes approximated soil moisture content in response to different levels of irrigation applications. An additional experiment, where irrigated land use was changed to grassland, was conducted to capture pre-irrigation land use and its impacts. It was found that regardless of strength of irrigation, precipitation decreased. In addition, the model did not produce precipitation over non-irrigated land use. When grassland replaced irrigated agriculture, increases in precipitation were estimated. With increased irrigation, latent heat flux increased compared to the control simulation and decreased when irrigation decreased. On the other hand, sensible heat flux was decreased compared to control when irrigation increased. The planetary boundary layer over irrigated land use was shallower than over non-irrigated land use while over grassland it was higher than irrigated but lower than non-irrigated land use. The changes in precipitation, the surface energy balance, and the planetary boundary layer served as a reminder of irrigation's complex effects on the atmosphere. Additional analysis of other precipitation events during GRAINEX would be helpful to better understand the effects of irrigation. [ABSTRACT FROM AUTHOR]

• The attenuation coefficient and sound velocity have a linear relationship with the precipitate. • When both precipitate and grain size deviate, the characteristic value of ultrasonic deviates. • The yield strength and microhardness can be accurately predicted by laser ultrasonics. • Laser ultrasonic can rapidly evaluate the microstructure and mechanical properties of aluminum alloys. The precipitation has an important influence on the mechanical properties of Al-Cu-Mg alloy. However, the metallographic and mechanical properties testing methods are not only time-consuming and laborious but also have a small detection area nowadays. In this paper, the laser ultrasonic non-contact detection technology is adopted, and the Al-Cu-Mg alloy rolled sheet with more precipitation is selected as the research object. The microstructure and mechanical properties of the standard samples were detected by scanning electron microscopy, electron backscatter diffraction and tensile test. Ultrasonic attenuation coefficient and sound velocity were obtained by laser ultrasonic test and Variational Modal Decomposition (VMD) method. The results show that, with the increase of solution temperature and solution time, the hard precipitate phase around the aluminum matrix gradually dissolves into it, and the solid solution strengthening is improved; at 500 °C and 360 min solution aging, the attenuation coefficient and sound velocity of ultrasound waves change abruptly, and it is judged that the precipitation phase and grain size are abnormal; the characteristics of ultrasonic signals and yield strength have a moderately good correlation with microhardness, and the yield strength and microhardness can be characterized by attenuation coefficient and sound velocity. This provides a new method for non-contact online inspection of Al-Cu-Mg aluminum alloys. [ABSTRACT FROM AUTHOR]

• We investigated the intra-annual runoff variations and periods in an endorheic lake basin-Issyk-Kul basin, Central Asia. • The runoff variability was investigated by using structuring models. • Analysis of the concentration and correlation of precipitation and runoff in the small bowl of the north Lake Issyk-Kull basin. This paper, based on the non-parametric tests and wavelet analysis, analyzed monthly precipitation and runoff data of the small basin in the northern part of the Lake Issyk-Kull basin over the nearly 62-year period, the concentration and correlation of precipitation and runoff in the small bowl of the north Lake Issyk-Kull basin. The results indicated that (1) the Cholpon-Ata River runoff (runoff 1) and the Chong-Ak-Suu River runoff (runoff 2) in the small watershed in the northern part of Lake Issyk-Kull basin are from June to April, January, and from September to November showed a significant increasing trend. The significant abrupt growth change occurred in 1983, while the precipitation at the Cholpon-Ata station showed a significant increasing trend in February, with a sharp point around 1980. (2) The concentration degree (Cd) index of runoff 1 in the small watershed in the northern part of the Lake Issyk-Kull basin has increased but not significantly, and the Cd index of precipitation and runoff 2 showed an insignificant decrease. (3) The Cd index of runoff 1 in the small watershed in the northern part of Lake Issyk-Kull basin existed for 10 years and 18 years, and the Cd index of River 2 existed for 9 years and 13 years. In contrast, the precipitation Cd index was significant at 4- and 15-year cycles. (4) On multiple time scales, they have a significant negative correlation between the runoff and precipitation in the small watershed in the northern part of the Lake Issyk-Kul basin from May to September. [ABSTRACT FROM AUTHOR]

Lithium hydroxide is currently a fundamental inorganic compound to produce Li-Ion batteries and therefore a key element in supporting the transition to electromobility. The essential need for large amounts of high purity LiOH materials makes it necessary for the industry to comply. This review provides a structured overview of the LiOH production processes over the last few decades. It presents methods, which are published in scientific journals, as well as in patents. The production methods are discussed in four main categories: electrochemical syntheses, precipitation reactions and recent developments like the selective Li+ extraction and waste recycling to obtain LiOH. This review also discusses the current industrial routes for LiOH production and shows the most important examples of each process in detail, providing valuable information for further development and enhancement of LiOH production methods in the future. [Display omitted] • This review gives a structured overview over production processes for LiOH. • Electrochemical, precipitation, extraction and recycling methods are displayed. • A brief overview over current industrial LiOH production is shown. • This paper compiles publications in scientific journals as well as in patents. [ABSTRACT FROM AUTHOR]

This paper matched the data for all non-financial listed firms in China from 1990 to 2017 with weather data and used temperature and precipitation to represent climate change. Using daily temperature and daily precipitation data, we constructed temperature bins and precipitation bins. This study presents a potential first empirical analysis that applies the risk perception theory to comprehensively examine the impacts of daily temperature and daily precipitation on firms' debt financing costs. Compared to a day with a suitable temperature, a day with temperatures above 30 °C increases firms' debt financing costs by 0.2411%. Compared to a sunny day, a day with torrential rain increases firms' financing costs by 0.2697%. Approximately $122.13 million and $20.49 million in extra costs were incurred across all firms in 2017. We conducted a series of heterogeneity tests. We found that the negative impacts of climate change on debt financing costs are greater for firms that investor considers more vulnerable. Finally, we found two possible mechanisms. First, from the firm's subjective initiative perspective, firms that respond proactively during seasons of high temperatures and heavy rains can reduce the negative impacts. Second, adverse weather caused by climate change may also increase firms' debt financing costs by blocking travel. These results enrich the literature on firms' debt financing costs and contribute to the understanding of climate change's impact on firms. [Display omitted] • An extra high-temperature day increases firms' debt financing cost by 0.2411%. • An extra heavy-rain day increases firms' debt financing costs by 0.2697%. • The negative impacts will be greater for those firms that investor considers more vulnerable. • Firms' response proactively can reduce the negative impacts. • Climate change also may increase firms' debt financing costs by blocking travel. [ABSTRACT FROM AUTHOR]