Average Evaporation Research Articles

The fluctuation characteristics of typical lakes in arid areas

Study regionThree typical lakes in Xinjiang, Ulungur Lake is a fractured lake, located in the north of the Junggar Basin; China's largest inland freshwater throughput lake named Bosten Lake; known for Barkol Lake’s salt content, it is also a closed inland lake. Study focusThe study aims to investigate and contrast the spatio-temporal variation characteristics of three lake types in Xinjiang and to evaluate the accuracy of four water body indices: NDWI, MNDWI, AWEI, and MAWEI. These indices reflect water body information by calculating differences in reflectivity. The research analyzes spatial and temporal variations of these typical Xinjiang lakes from 2001 to 2022 and explores the relationship between meteorological elements and lake regulation. New hydrological insights for the regionThe study examined the relationship between typical Xinjiang lakes and meteorological elements using wavelet coherence analysis and cross wavelet transform. The findings indicate that: 1) Among the three lakes, Ulungur Lake's area variation is most directly influenced by its average air temperature, evaporation, and precipitation. 2) In the semi-arid region, temperature significantly impacts the fluctuations of Bosten and Ulungur Lakes. Temperature affects Bosten Lake the most, accounting for 55.53 %, while Ulungur Lake is also primarily affected by temperature, accounting for 58.71 %. Barkol Lake is mostly influenced by precipitation, which accounts for 35.95 %. 3) Temporally, Bosten Lake exhibits the largest area change range, whereas Ulungur Lake shows the smallest. Spatially, Barkol Lake experiences the most significant changes, and Bosten Lake undergoes the least. This suggests that ERA5 data can be utilized for regional meteorological and hydrological trend studies, and the Google Earth Engine (GEE) platform's long-term water change monitoring capabilities may support sustainable development management of inland lakes.

Nanocellulose‐Based Interfacial Solar Evaporator: Integrating Sustainable Materials and Micro‐/Nano‐Architectures for Solar Desalination

AbstractClean‐water harvesting through solar interfacial evaporation technology has recently emerged as a strategy for resolving global water scarcity. In this study, rapid carbon‐dioxide‐laser‐induced carbonization and facile ice‐templating is employed to construct a cellulose‐based solar evaporator bearing a hybrid multi‐layer micro‐/nano‐architecture (i.e., a laser‐induced carbon (LC) nanostructure and a cellulose aerogel (CA) nano/microstructure). The LC exhibits a light‐absorbing/photothermal nanoporous carbon structure that offers high light absorption and multiple light scattering. Additionally, the CA exhibits numerous nanopores and unidirectional microchannels that facilitate rapid water transport via capillary action. This hybrid LC/CA micro‐/nano‐architecture enabled rapid vapor generation with an average water evaporation rate (ν) of 1.62 kg m−2 h−1 and an evaporation efficiency (η) of 66.6%. To further enhance the evaporation performance, a polydimethylsiloxane (PDMS) layer is coated onto the side of the LC/CA evaporator to increase its floatability in the simulated water; ν and η of the PDMS‐coated LC/CA evaporator (LC/CA/PDMS) increased to 1.9 kg m−2 h−1 and 83.8%, respectively. Additionally, the LC/CA/PDMS evaporator exhibited a high ν value of 1.68 kg m−2 h−1 in simulated seawater, originating from excellent resistance to salt accumulation via its self‐cleaning ability. Furthermore, the solar evaporator exhibited scalability for fabrication as well as biodegradable properties.

Janus Antipyretic Pastes for Efficient, Durable and Comfortable Personal Physical Cooling.

Prompt and prolonged cooling is extremely important when the body is in a fever state. Here, we proposed a concept of Janus antipyretic paste (JAP) with unique asymmetric wetting for effective and durable personal physical cooling. The prepared JAP possesses greater one-way transport capacity, and faster average water evaporation rate (∼2 times) than the original fabric. Compared to the wet cotton fabric (a reduction of ∼2.9 °C) and medical antipyretic paste (MAP) (no cooling after 5 h), the JAP achieved the best cooling effect and long cooling duration (cooling by 3.8 °C, at least 5-7 h) in practical application tests. In addition, the wearability of JAP is well validated, including its excellent breathability and good flexibility, which can maximum improve the comfort of our body. We believe the new JAP with superior cooling and comfort properties will provide promising design guidelines for the next generation of family or hospital physical cooling products.

Design of honeycomb-imitated composite hydrophobic aerogel and applications for multifunctional water cleaning

It is a huge challenge to integrate comprehensive properties in photothermal materials for multifunctional application in various aspects of water cleaning and purification. In this study, inspired by honeycombs, a polysiloxane/polyimide/carbon composite hydrophobic aerogel (Bio-SPC aerogel) is fabricated using a blending-crosslinking-directional freezing-gradient heating method, and exhibits reasonable structure and component regulation for multiple applications such as oil–water separation, photothermal crude absorption and water evaporation. Primary vertical porous channels and the secondary structure of fibrous carbon on the aerogel’s cell walls reduce light reflection and provide a large light absorption area, respectively, promoting photothermal conversion properties. Another secondary structure of micro-nano pores enhances heat preservation. Through convenient pre-processing and directional freeze-drying, methyltrimethoxysilane is hydrolysis-condensed and bound to the structure skeleton formed using polyimide precursor and bacterial cellulose biomass, coating on the surface to mimic beeswax’s enhanced hydrophobicity and mechanical strength. The aerogel exhibits a mechanical strength of 32 kPa at 80 % strain and good structural stability over 500 cycles, as well as efficient light-to-heat conversion with a fast temperature increase (reaching 75.3℃ in 30 s) and a maximum stable temperature of nearly 100℃. Its solvent absorption capacity is 74.2 g/g and it has a flux retention rate of 71 % after 10 cycles of oil–water separation. Under sunlight irradiation, the aerogel absorbs crude oil more quickly during cleanup. The assembled aerogel evaporator has an average evaporation rate 4.2 times that of bulk water and 96.6 % efficiency. The evaporation performance is stable in high-concentration saline water and long-term cycles, with a maximum rate of 2.675 kg m-2 h−1 outdoors. This novel honeycomb-inspired composite aerogel shows promise for multifunctional applications, including oily water cleaning, crude cleanup, seawater desalination, and heavy metal or organic dye removal from polluted water.

High salt-resistant and robust MXene@oleylamine/PET composite nonwoven for efficient and long-term solar desalination

2D transition metal carbides/nitrides/carbonitrides (MXenes) have received extensive attention in solar seawater desalination due to their hydrophilicity, 100 % photothermal conversion efficiency, and efficient light-trapping by enhancing localized surface plasmon resonance (LSPR). Nevertheless, the easily oxidizable characteristics of MXenes, along with salt accumulation and structural weakness impede their practical application in solar-driven interfacial evaporators. Herein, a hydrophobic MXene@oleylamine/polyethylene terephthalate (MXene@OAm/PET) nonwoven with long-term operational stability is fabricated via firmly chemical cross-linking between oleylamine (OAm) modified MXene (MXene@OAm) and NH2-PEG-COOH treated PET nonwoven (PEG-PET). The MXene@OAm endows excellent oxidation resistance and hydrophobicity. The prepared MXene@OAm/PET nonwoven which exhibits broad-spectrum solar absorption and high efficiency, can achieve an average evaporation rate in 3.5 wt% NaCl solution at 1.26 kg·m−2·h−1 and no seeable salt deposition during 15 irradiation cycles for 8 h a day indicates its superior salt resistance and long-term stability. Most importantly, after being soaked in 3.5 wt% NaCl solution for 40 days, the evaporation rate of MXene@OAm/PET nonwoven still remains stable at around 1.22 kg·m−2·h−1, indicating the significant potential of this prepared nonwoven for long-term seawater desalination and its suitability for industrial applications. Even in industrial wastewater, the evaporation rate can reach 1.27 kg·m−2·h−1. This work demonstrates a successful strategy for achieving high efficiency, stability, and superior salt resistance, which can be potentially utilized in seawater desalination and wastewater treatment.

Tree-like 3D GNP-rPN composite structure for solar-thermal evaporation and photocatalytic degradation of antibiotic wastewater

To realize high-yield and long-term purification of wastewater containing antibiotic ciprofloxacin hydrochloride (CIP) and seawater, a tree-like 3D GNP-rPN solar-driven water evaporation and photocatalysis evaporator is developed by preparing and assembling GO/NPDI/PVA (GNP) hydrogel (canopy) and rGO/PU/NPDI (rPN) foam (trunk). The “tree-like” evaporation and photocatalysis evaporator design in this work has the following three characteristics: First of all, graphene oxide (GO) and reduced graphene oxide (rGO) sheets broaden the light absorption range of the photocatalyst perylene imide nanowires (NPDI), which facilitates absorption of more sunlight; secondly, GO and rGO adsorb pollutants in water and provide them to NPDI for catalytic degradation under sunlight irradiation because of their huge specific surface area; thirdly, the excellent photothermal conversion ability of GO and rGO converts solar energy into heat energy, thus facilitating the catalytic degradation of CIP by NPDI. Thanks to the reduced enthalpy of water evaporation by GNP hydrogel, the sufficient top-down water supply, the superior photocatalytic performance of NPDI nanowires, and the efficient solar light absorption and solar-thermal energy conversion of the GO sheets and NPDI nanowires, the resultant GNP-rPN evaporation and photocatalysis system achieves an average water evaporation rate of 2.84 kg m−2 h−1 and a CIP degradation efficiency of 74.04 % within 1 h under 1-sun irradiation. The GNP-rPN system exhibits an optimal degradation efficiency of 74.04 % for a CIP solution with an initial concentration of 10 mg/L within 1 h of irradiation, reaching a degradation efficiency of 96.37 % after 4 h, demonstrating its effectiveness in purifying antibiotic-laden wastewater.

Numerical investigation on cavitation erosion and evolution of choked flow in a tri-eccentric butterfly valve

The tri-eccentric butterfly valve is widely utilized in the petrochemical, nuclear, and metallurgy industries due to its robust sealing performance and great pressure resistance. When the local static pressure is lower than the saturation vapor pressure, the fluid phase is transformed into vapor, and cavitation occurs. Cavitation intensifies and the bubbles generated by cavitation severely hinder the flow when the inlet pressure remains constant and the outlet pressure further decreases. This phenomenon is known as choked flow. Choked flow is a derivative phenomenon of cavitation, which seriously threatens the lifetime of valves and the safety of the operation system. In this paper, a multiphase flow of the tri-eccentric butterfly valve is modeled to investigate the choked flow characteristics. The numerical results based on the proposed model are in good agreement with the experiments. The effect of the pressure drop on the mass flow rate and flow coefficient is studied and the liquid pressure recovery factor of the tri-eccentric butterfly is determined at the certain valve opening degree based on the Schnerr and Sauer cavitation model. The relationship between the pressure ratio and choked flow is studied by pressure and velocity contours. The susceptible erosion locations and primary causes of erosion for the tri-eccentric butterfly valve at the certain valve opening degree are investigated. By comparison of the distribution of the vapor volume fraction and vortex structures, the spatial correlation between vortex and choked flow is revealed. Meanwhile, the effect of the pressure ratios on the average vapor volume fraction at 70 % and 100 % valve opening degrees is studied. The evolution of choked flow in the tri-eccentric butterfly is revealed and the cause of choking is pointed out.

Theoretical analysis of water-droplet condensation and evaporation in prescribed environment with radiation

Abstract A quasi-explicit algebraic solution of the problem of quasi-steady water droplet heat- and mass-transfer with condensation or evaporation in a prescribed environment including radiation has been obtained. The solution is based on the mass-fraction form of Fick’s law of species diffusive mass transport, which allows accounting for variation in gas density through the diffusion layer surrounding the droplet. A new term, the average vapor supersaturation through the diffusion layer, has been included that allows the model to be extended to environmental conditions significantly outside those for which it is theoretically derived (dilute or near-saturation), even to conditions of relatively high temperature, low relative humidity, and low pressure. The latter two have atmospheric significance because evaporative cooling can induce significant decrease in droplet temperature and possibly induce freezing. Basic modeling assumptions are confirmed by comparison with time-dependent temperature and evaporation-rate measurements of a laboratory laser-heated droplet. Accuracy of the new model is assessed by comparison with exact equations. For temperatures between −30 and 0°C and negligible radiation, relative-error magnitudes in droplet temperature and evaporation rate are less than 5%, even for relative humidity down to 10% and pressure down to 60 kPa. This represents an improvement in accuracy over the conventional model, in which property variations of density and supersaturation through the diffusion layer are not taken into account. Differences in predicted evaporation rates between the mass-fraction and the more common partial-density Fick’s laws, which can be significant (>10% above 70% relative humidity) in coupled, implicit equations, are shown to be made negligibly small (<0.5%) by linearizing about the saturation state.

Multiple-Win Effects and Beneficial Implications from Analyzing Long-Term Variations of Carbon Exchange in a Subtropical Coniferous Plantation in China

To improve our understanding of the carbon balance, it is significant to study long-term variations of all components of carbon exchange and their driving factors. Gross primary production (GPP), respiration (Re), and net ecosystem productivity (NEP) from the hourly to the annual sums in a subtropical coniferous forest in China during 2003–2017 were calculated using empirical models developed previously in terms of PAR (photosynthetically active radiation), and meteorological parameters, GPP, Re, and NEP were calculated. The calculated GPP, Re, and NEP were in reasonable agreement with the observations, and their seasonal and interannual variations were well reproduced. The model-estimated annual sums of GPP and Re over 2003–2017 were larger than the observations of 11.38% and 5.52%, respectively, and the model-simulated NEP was lower by 34.99%. The GPP, Re, and NEP showed clear interannual variations, and both the calculated and the observed annual sums of GPPs increased on average by 1.04% and 0.93%, respectively, while the Re values increased by 4.57% and 1.06% between 2003 and 2017. The calculated and the observed annual sums of NEPs/NEEs (net ecosystem exchange) decreased/increased by 1.04%/0.93%, respectively, which exhibited an increase of the carbon sink at the experimental site. During the period 2003–2017, the annual averages of PAR and the air temperature decreased by 0.28% and 0.02%, respectively, while the annual average water vapor pressure increased by 0.87%. The increase in water vapor contributed to the increases of GPP, Re, and NEE in 2003–2017. Good linear and non-linear relationships were found between the monthly calculated GPP and the satellite solar-induced fluorescence (SIF) and then applied to compute GPP with relative biases of annual sums of GPP of 5.20% and 4.88%, respectively. Large amounts of CO2 were produced in a clean atmosphere, indicating a clean atmospheric environment will enhance CO2 storage in plants, i.e., clean atmosphere is beneficial to human health and carbon sink, as well as slowing down climate warming.

Vertical Distribution of Water Vapor During Haze Processes in Northeast China Based on Raman Lidar Measurements

Haze refers to an atmospheric phenomenon with extremely low visibility, which has significant impacts on human health and safety. Water vapor alters the scattering properties of atmospheric particulate matter, thus affecting visibility. A comprehensive analysis of the role of water vapor in haze formation is of great scientific significance for forecasting severe pollution weather events. This study investigates the distribution characteristics and variations of water vapor during haze weather in Changchun City (44°N, 125.5°E) in autumn and winter seasons, aiming to reveal the relationship between haze and atmospheric water vapor content. Analysis of observational results for a period of two months (October to November 2023) from a three-wavelength Raman lidar deployed at the site reveals that atmospheric water vapor content is mainly concentrated below 5 km, accounting for 64% to 99% of the total water vapor below 10 km. Furthermore, water vapor content in air pollution exhibits distinct stratification characteristics with altitude, especially within the height range of 1–3 km, where significant water vapor variation layers exist, showing spatial consistency with inversion layers. Statistical analysis of haze events at the site indicates a high correlation between the concentration variations of PM2.5 and PM10 and the variations in average water vapor mixing ratio (WVMR). During haze episodes, the average WVMR within 3 km altitude is 3–4 times higher than that during clear weather. Analysis of spatiotemporal height maps of aerosols and water vapor during a typical haze event suggests that the relative stability of the atmospheric boundary layer may hinder the vertical transport and diffusion of aerosols. This, in turn, could lead to a sharp increase in aerosol extinction coefficients through hygroscopic growth, thereby possibly exacerbating haze processes. These observational findings indicate that water vapor might play a significant role in haze formation, emphasizing the potential importance of observing the vertical distribution of water vapor for better simulation and prediction of haze events.

Comparative Performance Assessment between Incompressible and Compressible Solvers to Simulate a Cavitating Wake

To study the effects of fluid compressibility on the dynamics of a cavitating vortex street flow in a regime where the vortex shedding frequency increases as a result of the cavitation increase, the cavitating wake behind a wedge was simulated employing both incompressible and compressible solvers. To do this, a compressible cavitation model was implemented, modifying the Zwart-Gerber-Belamri (ZGB) incompressible solver and including a pressure limit and absorbing boundary conditions to prevent a non-physical pressure field. To validate the performance of the compressible model, preliminary simulations were carried out on a 1D Sod cavitating tube and the cavitating vortex shedding behind a circular body at laminar flow conditions. The results of the cavitating wake behind the wedge with the incompressible and the compressible solvers showed similar predictions in terms of pressure, vortex shedding frequency, and instantaneous and average vapor volume fraction profiles. In spite of this, differences were obtained in the energy content of the fluid force fluctuations on the body at higher frequencies, which appear to be better resolved and amplified when the compressibility model is considered. Overall, both solvers provided comparable results in terms of cavitation phenomena that are well aligned with experimental observations.

A large-scale-outdoor continuous release of cryogenic liquid onto ground

The accidental release of cryogenic liquids can cause several hazards to humans, assets, and the environment. Therefore, this phenomenon has drawn significant attention and has been investigated as part of quantitative risk assessment associated with the use of cryogenic liquids. However, the effects of release conditions on pool spread have not been thoroughly studied, and the mechanism of pool retraction has not been discussed. In this study, an attempt was made to address these gaps by both experimental and numerical analyses. Firstly, large-scale-outdoor release tests with a systematic measurement system were performed using liquid nitrogen to compare with large-scale release tests of liquid hydrogen. The release height and orientation were varied. It was observed that the pool shape was affected by the release orientation. However, the maximum pool size and average vaporization rate were insensitive to both the release height and orientation. The conductive heat from the ground was confirmed to be the major heat source for pool vaporization, accounting for over 90 % of the total heat transferred into the liquid pool. Subsequently, release scenarios were simulated using integral source models. Especially, several hypotheses were thoroughly discussed, implemented in the source models, and validated against experimental results to determine the most appropriate mechanism for pool retraction. The findings of this study are expected to be beneficial for the consequence estimation of cryogenic release scenarios and for the validation and improvement of source models.

Prediction of Soil Temperature in Wheat Field Using Machine Learning Models

ABSTRACT Wheat is a very vital cereal crop in the development of a nation’s economy and agricultural sector. A crucial element that profoundly affects the growth and productivity of wheat is the soil temperature. As an insulating layer, straw mulch controls the soil temperature. Field measurement of the soil temperature is time-consuming and costly; therefore, the present study investigates the applicability of random forest (RF), support vector machine (SVM) and generalized regression neural network (GRNN) models for estimating soil temperature in wheat fields covered with straw mulch using meteorological, soil cover and agronomical parameters. A field study was conducted on the wheat cultivar with two soil cover treatments for measuring the soil temperature at three depths (5, 50 and 80 cm). Soil plant analysis development value; soil cover and depth; daily meteorological data such as average air temperature, average relative humidity, sunshine hours and vapor pressure were used as inputs for machine learning models in training and testing. Statistical performance indicators showed applicability of three models with a root mean square error (RMSE) ranging from 0.245–0.595°C, 0.867–0.886°C and 0.557–0.812°C, Nash-Sutcliffe efficiency (NSE) ranging from 0.917–0.987, 0.823–0.836 and 0.804–0.935 and Lin’s concordance correlation coefficient (CCC) ranging from 0.949–0.991, 0.887–0.897 and 0.881–0.957 for the RF, SVM and GRNN, respectively. Results indicated better performance of the RF model for predicting the soil temperature at different depths in the case of both crop and soil cover conditions. Also, the uncertainty analysis indicated the better performance of RF with R-factor and P-factor value of 0.40 and 0.84, respectively.

Three-Dimensional Double-Layer Multi-Stage Thermal Management Fabric for Solar Desalination.

Water scarcity is a serious threat to the survival and development of mankind. Interfacial solar steam generation (ISSG) can alleviate the global freshwater shortage by converting sustainable solar power into thermal energy for desalination. ISSG possesses many advantages such as high photothermal efficiency, robust durability, and environmental friendliness. However, conventional evaporators suffered from huge heat losses in the evaporation process due to the lack of efficient thermal management. Herein, hydrophilic Tencel yarn is applied to fabricate a three-dimensional double-layer fabric evaporator (DLE) with efficient multi-stage thermal management. DLE enables multiple solar absorptions, promotes cold evaporation, and optimizes thermal management. The airflow was utilized after structure engineering for enhanced energy evaporation efficiency. The evaporation rate can reach 2.86 kg·m-2·h-1 under 1 sun (1 kW·m-2), and 6.26 kg·m-2·h-1 at a wind speed of 3 m·s-1. After a long duration of outdoor operation, the average daily evaporation rate remains stable at over 8.9 kg·m-2, and the removal rate of metal ions in seawater reaches 99%. Overall, DLE with efficient and durable three-dimensional multi-stage thermal management exhibits excellent practicality for solar desalination.

Exploring novel approaches on impact of micro-fin tubes on flow boiling heat transfer using R134a refrigerant: A parametric case study

This paper experimentally investigates the factors influencing the flow boiling heat transfer of R134a refrigerant within smooth and micro-fin tubes having an outer diameter of 9.52 mm. The tube has a peculiar micro-fin shape with a 46° apex angle and 22° helix angle, producing a surface area 1.62 times bigger than a smooth tube of identical diameter. The main goal of the study is to understand the influences of mass flux, heat flux, saturation temperature, and average vapor quality on heat transfer characteristics. The findings are initially compared with known flow boiling correlations; moreover, performance index, penalty factor, and enhancement factor considerations are also made. The heat transfer coefficient (HTC) relies on mass flux, with significant improvements at G = 200 kg m−2 s−1, despite dry-out difficulties at high vapor quality. Intensified flow velocity from higher mass flux causes a rise in frictional pressure drop (FPD), with micro-fin tubes demonstrating superior heat transfer, owing to their larger surface area and improved swirl formation. Compared to smooth tubes, FPD is significantly influenced by vapor quality for micro-fin tubes. The study analyses the importance of micro-fin tubes to improve heat transfer in industrial applications, as well as the effects of saturation temperature and vapor quality on HTC.

Plant transpiration inspired biomass-derived solar evaporator for highly efficient solar vapor generation

The interface solar evaporation is an energy-saving and environmentally friendly method for seawater desalination and sewage purification. In this work, a biomimetic solar evaporator (ppy@AZL) inspired by plant transpiration was designed to achieve high efficient vapor generation. The ppy@AZL evaporator was made of zizania latifolia as raw material, has a cellulose skeleton with high water transport after alkalization and was decorated with photothermal polypyrrole to form bionic branches and leaves, and has excellent photothermal conversion performance. The evaporation performance and potential application of ppy@AZL evaporator in seawater desalination and sewage treatment were studied. The results indicated that the average evaporation rate of the ppy@AZL in simulated seawater (3.5 wt%) under the irradiation of one sun (1 kW m−2) was 2.239 kg m−2 h−1, and the photothermal conversion efficiency was 93.4 % in this work. In addition, the ppy@AZL evaporator has excellent evaporation rate of 2.668 kg m−2 h−1 in 9 h outdoor continuous evaporation experiment of simulated seawater (3.5 wt%), and can continuously and stably generate vapor. Therefore, this study provided a new solar evaporator with low-cost, simple preparation, better salt resistance, and high evaporation performance for seawater desalination and sewage treatment.

Relationship between interannual variability of the north edge of the East Asian summer monsoon and extreme precipitation in North China

The north edge of the East Asian summer monsoon (EASM) is defined by using the isoline with average total column water vapor (TCWV) equal to 25 mm, and the relationship between the north edge of the EASM and summer extreme precipitation in North China (NC) from 1961 to 2020 is discussed. Self-Organizing Maps (SOM) method is used to cluster extreme precipitation in the abnormal years of the north edge in NC, and the circulation characteristics of different types of extreme precipitation are discussed. The results show that the north edge of the EASM is closely related to extreme precipitation in NC. When the north edge is northerly, both the frequency and total amount of extreme precipitation increase significantly in the monsoon marginal zone. Based on different monsoon circulation background, summer extreme precipitation events in NC are divided into four categories, namely, the central type and southern type in the northerly years of north edge, and the central type and eastern type in the southerly years of north edge. The occurrence of different types of extreme precipitation is closely related to the different characteristics of local trough, the western Pacific subtropical high (WPSH), and wave trains in the middle and high latitudes. Specifically, the central type extreme precipitation is affected by the mid-latitude wave train in the northerly years of north edge. As for the central type extreme precipitation in the southerly years of north edge, both high-latitude and mid-latitude wave trains transfer from west to east and converge over NC. However, the wave disturbance energy is relatively weak, leading to the extreme precipitation with weak intensity.

Enhancing Water and Soil Resources Utilization via Wolfberry-Alfalfa Intercropping.

The impact of the intercropping system on the soil-plant-atmosphere continuum (SPAC), encompassing soil evaporation, soil moisture dynamics, and crop transpiration, remains an area of uncertainty. Field experiments were conducted for two years in conjunction with the SIMDualKc (Simulation Dual Crop Coefficient) model to simulate two planting configurations: sole-cropped wolfberry (Lycium barbarum L.) (D) and wolfberry intercropped with alfalfa (Medicago sativa L.) (J). These configurations were subjected to different irrigation levels: full irrigation (W1, 75-85% θfc), mild deficit irrigation (W2, 65-75% θfc), moderate deficit irrigation (W3, 55-65% θfc), and severe deficit irrigation (W4, 45-55% θfc). The findings revealed that the JW1 treatment reduced the annual average soil evaporation by 32% compared with that of DW1. Additionally, mild, moderate, and severe deficit irrigation reduced soil evaporation by 17, 24, and 36%, respectively, compared with full irrigation. The intercropping system exhibited a more efficient canopy structure, resulting in reduced soil evaporation and alleviation of water stress to a certain extent. In terms of temporal dynamics, monocropping resulted in soil moisture levels from 1% to 15% higher than intercropping, with the most significant differences manifesting in the mid to late stages, whereas differences in the early stages were not statistically significant. Spatially, the intercropping system exhibited 7-19% lower soil water contents (SWCs) than sole cropping, primarily within the root water uptake zone within the 0-60 cm soil layer. The intercropping system showed an enhanced water absorption capacity for plant transpiration, resulting in a 29% increase in transpiration compared with sole cropping, thereby achieving water-saving benefits. These findings contribute to our understanding of the agronomic and environmental implications of intercropping wolfberry and alfalfa in arid regions and provide insights into optimizing water and soil resource management for sustainable agricultural practices.

Salt Resistant PPy/MXene Flexible Waffle Type Fabric for Efficient Solar Evaporation and Water Purification Production.

In recent years, with the development of solar seawater desalination technology, many solar evaporators are affected by precipitated salts during the evaporation process, which can reduce efficiency. In this work, flexible fabrics made of polypyrrole (PPy)/MXene are obtained by impregnating the prepared PPy ink onto waffle like fabrics. The combination of PPy and fabric greatly improves the water absorption and evaporation performance of the fabric. The average evaporation rate of this structure is 1.43kg m-2 h-1, and the average evaporation efficiency under a single light source is 85.13%. After a 15-h testing cycle and a total of 8 cycles, lasting nearly 120 h, the performance of the device remained stable. The structural characteristics of waffle fabric, based on the Marangoni thermal effect, make it possible to suppress salt precipitation during evaporation, avoiding large salt particles covering the evaporation surface and reducing efficiency. This experiment successfully demonstrated long-term stable water evaporation, providing new ideas for the development of fabric evaporators.

A self-floating and windproof Janus biomass composite hydrogel with magnetic controllability and salt rejection for polluted seawater desalination

To alleviate the global freshwater crisis, a self-floating magnetic Janus biomass composite hydrogel has been fabricated through a rational asymmetric bilayer structure design, which exhibits many merits such as remarkable light-absorption, photothermal conversion, water-evaporation, salt rejection, wind-resistant, etc. Specifically, sodium alginate, cellulose nanofibrils (from corn straw), and acrylic acid were crosslinked by triple interpenetrating networks (chemical cross-linking, ionic cross-linking and hydrogen bonding). Janus hydrogel evaporator was constructed by incorporating the top layer containing light-absorbing core–shell magnetic nanoparticles (Fe3O4@PDA NPs), and the bottom layer composed of self-floating foam gel due to the addition of foaming agent. Under one solar irradiation, the average evaporation rate and photothermal conversion efficiency of Janus biomass composite hydrogel reached 2.89 ± 0.09 kg·m−2·h−1 and 95.66 ± 2.68 %, respectively. Its evaporation stability and salt tolerance capability have been demonstrated by extended period of simulated desalination. Furthermore, Janus biomass composite hydrogel also had excellent mechanical property (ultimate stress of 1.6 MPa) and magnetic performance, which can not only effectively resist the stress induced by wind and waves, but also enable the magnetic maneuvering and wind-resistance floating on the sea. When the input voltage of electromagnet was 24 V, the furtherest response displacement and maximum resisted wind speed were 9 cm and 7.2 m/s, respectively. Therefore, such magnetic self-floating Janus biomass composite hydrogel serving as interfacial solar-driven evaporator system offers a green, efficient and sustainable solution for clean freshwater production.