Surface Evaporation Research Articles

Analysis of Runoff Variation Characteristics and Influencing Factors in the Typical Watershed of Miyun Reservoir, China

As an important drinking water source for Beijing, the capital of China, the water inflow of Miyun Reservoir has been decreasing year by year, which has affected the urban water supply security. To understand the variation trend of the inflow and analyze the main factors influencing the runoff change, this research focused on the watershed of Miyun Reservoir as the target. Based on the runoff data from 1984 to 2020 at the outlet of the basin, as well as the precipitation, potential evaporation intensity, NDVI (normalized difference vegetation index), population, and GDP (Gross Domestic Product) data, combined with correlation analysis methods, empirical statistical methods, the SCRCQ (Slope Change Ratio of Cumulative Quantity) method, and the GIS, the interannual variation characteristics of various elements in the basin were analyzed, the correlation between runoff and other factors was studied, and the influencing degrees of precipitation, water surface evaporation intensity, human activities, and other factors on the runoff change in the basin were quantitatively separated. The research results showed that the runoff exhibited a distinct decreasing trend, and there were two mutation points in the basin runoff from 1984 to 2020, which were 1995 and 2014, respectively. The runoff change was divided into three stages: 1984–1995 (upward trend in T1), 1995–2014 (downward trend in T2), and 2014–2020 (stable trend in T3). Runoff was significantly correlated with four indicators: the summer leaf area index of the Chaohe River and Baihe River, the regional GDP and population, among which the correlation of the summer leaf area index was the largest. Compared with the period T1, the contribution rates of climate change to the runoff reduction in T2 and T3 were 6.38% and 5.73%, and the contribution rates of human activities to the runoff reduction were 93.62% and 94.27%, respectively. Therefore, the change in annual runoff in the Miyun Reservoir watershed is mainly affected by human activities, and the contribution of climate change to the runoff attenuation is weak. This study is significant in the maintenance and enhancement of runoff in typical watershed.

Electrical Impedance Tomography Monitoring of Salt Transportation in Cellulose Hydrogel for Solar‐Driven Evaporative Desalination via Laser Defined Wettability

AbstractThe scarcity of clean water has become a growing problem worldwide. Solar‐driven desalination based on evaporation has become a promising green technology for obtaining drinking water from saline water for the welfare of human society. However, the accumulation of salt precipitated from the saline at the evaporator surface remains a severe problem in improving evaporation efficiency. To overcome this problem, it is crucial to investigate the transportation mechanism of salt in the saline during the evaporation process. Herein, an in situ monitoring strategy with the electrical impedance tomography (EIT) method is proposed to characterize the salt transportation and accumulation process inside the nano‐crystal cellulose (NCC)‐MnO2 nanoparticle solar evaporator. The coating of laser‐induced graphene (LIG) with tunable water wettability shows that the hydrophobic structures can suppress salt accumulation during evaporation. The collected condensation water generated from the bacteria‐polluted saline proves to be clean. It is hoped that this work can further inspire research on the salt‐resistive evaporator design.

Effects of Straw Decomposition on Soil Surface Evaporation Resistance and Evaporation Simulation

As a prominent agricultural country, China has widely implemented returning straw to the field in agricultural production. However, as the decomposition of straw progresses, the physical properties of the soil change, inevitably leading to alterations in the soil surface evaporation model. This study investigated the variations in soil evaporation rate, soil moisture content over 60 days after returning straw to the field, and bare soil through two leaching pond experiments. Through soil moisture retention curves at different degrees of decomposition, this study analyzed the impact of straw decomposition on soil’s water retention capacity. Based on measured data, this study formulated models for the soil surface evaporation resistance of bare soil and varying degrees of straw decomposition. With the comparison and contrast between the models, this study clarified the impact of straw decomposition on soil surface evaporation resistance. The main conclusions are the following: The moisture content of the surface soil decreases exponentially over time and, after 40 days of straw decomposition, the water content of the soil under decomposition is higher than that of bare soil. As the moisture content decreases, the cumulative evaporation from the soil increases linearly. The cumulative evaporation of the decomposed straw soil is lower than that of bare soil, with a relative reduction ranging from 3.08% to 32.2%. The straw decomposition significantly enhances the water retention capacity of the soil in the medium-to-high suction range. The straw decomposition enhances the evaporation resistance of the soil surface, and the greater the degree of decomposition, the more significant the enhancement effect. The research findings not only provide a scientific basis for agricultural water management, but also possess practical implications for guiding farmers to adopt more effective moisture retention measures.

Do land models miss key soil hydrological processes controlling soil moisture memory?

Abstract. Soil moisture memory (SMM), which refers to how long a perturbation in soil moisture (SM) can last, is critical for understanding climatic, hydrological, and ecosystem interactions. Most land surface models (LSMs) tend to overestimate surface soil moisture and its persistency (or SMM), sustaining spuriously large soil surface evaporation during dry-down periods. We attempt to answer a question: do LSMs miss or misrepresent key hydrological processes controlling SMM? We use a version of Noah-MP with advanced hydrology that explicitly represents preferential flow and surface ponding and provides optional schemes of soil hydraulics. We test the effects of these processes, which are generally missed by most LSMs in SMM. We compare SMMs computed from various Noah-MP configurations against that derived from the Soil Moisture Active Passive (SMAP) L3 soil moisture and in situ measurements from the International Soil Moisture Network (ISMN) from the years 2015 to 2019 over the contiguous United States (CONUS). The results suggest that (1) soil hydraulics plays a dominant role and the Van Genuchten hydraulic scheme reduces the overestimation of the long-term surface SMM produced by the Brooks–Corey scheme, which is commonly used in LSMs; (2) explicitly representing surface ponding enhances SMM for both the surface layer and the root zone; and (3) representing preferential flow improves the overall representation of soil moisture dynamics. The combination of these missing schemes can significantly improve the long-term memory overestimation and short-term memory underestimation issues in LSMs. We suggest that LSMs for use in seasonal-to-subseasonal climate prediction should, at least, adopt the Van Genuchten hydraulic scheme.

Study on Influence of Microwave Electric Field Direction on Evaporation Based on Molecular Dynamics.

Microwave-assisted evaporation technology is widely used today, but its molecular mechanism is not fully understood. To investigate the molecular mechanism of the influence of microwave electric field direction on water evaporation, this paper designed experiments to measure the microwave energy required to evaporate each gram of water with electric field directions parallel and perpendicular to the water surface. The temperature rise curve of the water is controlled to be consistent in both cases, and the temperature distribution of the water is made uniform by stirring. We found a stable difference in the energy absorbed by the two situations, indicating that the direction of the microwave electric field has an effect on water evaporation. In this article, the evaporation behavior of water molecules under different directional electric fields was then studied by molecular dynamics. The SPCE water molecule model, which simulates pure water systems well, was selected for this calculation. Based on the GROMOS force field, the evaporation enthalpy and surface tension of water under various conditions at constant temperature were calculated and the conclusions were analyzed. The calculated results are in agreement with the experimental results, and the influence of the evaporation enthalpy of water molecules is related to the direction of the microwave electric field.

Quantitative impacts of climate change and human activities on grassland growth in Xinjiang, China.

Grassland is an important vegetation type in Xinjiang, China, playing a crucial role in the terrestrial carbon cycle. Previous studies have shown that both climate change and human activities significantly impact grassland growth. However, research quantifying the contributions of these two factors to grassland changes is still not thorough enough. This study utilized remote sensing data, i.e., Normalized Difference Vegetation Index (NDVI), to analyze the spatial trends of grassland changes from 1982 to 2015, and the correlation between NDVI and climate factors. Then, relative contributions of climate change and human activities to grassland changes were explored across Xinjiang. The results indicated that there was a significant spatial heterogeneity in the interannual variations of NDVI in the study area, showing an overall increasing trend (covering 62.5% of the study area). This was mainly attributed to the warming and humidifying trend of Xinjiang's climate in recent decades, where increased precipitation and rising temperatures promoted grassland growth. The main regions with increased NDVI included the western part of Changji Hui Autonomous Prefecture, the southern part of Tacheng Prefecture, and the northwestern part of the Tarim Basin; while the areas with decreased NDVI were mainly located in the western part of the study area, e.g., the Ili River basin, and the Tekes River basin. Compared to precipitation, NDVI showed a stronger correlation with temperature, which was related to temperature promoting organic matter decomposition and enhancing vegetation nutrient utilization efficiency. NDVI was negatively correlated with VPD, mainly due to the effects of transpiration and surface evaporation. In terms of grassland growth, climate change (52%) contributed as much as human activity (48%). For the grassland reduction, human activities played a larger role. Overall, in mountainous and flat areas, human activities contributed more (64.29%) than climate change (35.71%), including activities such as grazing and urbanization.

A Multifunctional Synergistic Solar-Driven Interfacial Evaporator for Desalination and Photocatalytic Degradation.

The scarcity of freshwater resources and the treatment of dye wastewater have emerged as unavoidable challenges that need to be addressed. The combination of solar-driven interfacial evaporation, photocatalytic degradation, and superhydrophobic surface provides an effective approach for seawater desalination and the treatment of organic dyes. In this study, we fabricated a multifunctional synergistic solar evaporator by depositing cupric oxide nanoparticles onto polypyrrole (PPy) coating and subsequently modified it with a hydrophobic agent successfully. The evaporator achieved an evaporation rate of 1.48 kg m-2 h-1 under 1 kW m-2 irradiation. Importantly, the evaporator exhibited a degradation efficiency of 95.9% toward the organic dye methylene blue. It is important to mention that PPy promotes the separation of photogenerated electron-hole pairs, thus improving the photocatalytic performance of cupric oxide. The salt resistance of the evaporator is evidenced by the absence of significant salt deposits on its surface even after 300 min of operation due to its superhydrophobic property. The evaporator also presents excellent resistance to acidic/alkaline/high-temperature/organic solvent environments. This solar evaporator offers a sustainable solution for water purification.

A novel sea surface evaporation scheme assessed by the thermal rotating shallow water model

AbstractIn this study, a novel sea surface evaporation scheme, along with its corresponding bulk aerodynamic formulation, is proposed to estimate sea surface evaporation, columnar humidity, and precipitation distribution within the atmosphere. The scheme is based on three distinct functions, each dependent on a single variable: zonal wind velocity, tropospheric (potential) temperature, and free convection. It is shown that the normalized Clausius–Clapeyron formula requires an adjustable scaling factor for real‐world applications, calibrated using empirical fitness curves. To validate the proposed approach, we employ a model based on the pseudo‐spectral moist‐convective thermal rotating shallow water model, with minimal parameterization over the entire sphere. ECMWF Reanalysis 5th Generation (ERA5) reanalysis data are used to compare the model's results with observations. The model is tested across different seasons to assess its reliability under various weather conditions. The Dedalus algorithm, which handles spin‐weighted spherical harmonics, is employed to address the pseudo‐spectral problem‐solving tasks of the model.

Comparative Effects of Superhydrophobic Sand and Plastic Mulches on Growth and Yield of Sweet Pepper (Capsicum annum L.) under Arid Environments

Superhydrophobic sand (SHS) is a plastic-free mulching technology that reduces surface evaporation of water from irrigated soils. Here, we present the results of two experimental field trials conducted in the 2019–20 and 2021–22 cropping seasons, comparing the efficacy of SHS with those of traditional plastic mulches on the growth and yield performance of sweet pepper (Capsicum annum L.) plants. The experiments were conducted at the King Abdulaziz University (KAU) agriculture research station at Hada Al-Sham (21˚48′3″N, 39˚43′25″E), Al-Jamoom, Saudi Arabia. The effects of bare soil (i.e., control treatment), 5 mm SHS thickness, and 10 mm SHS thickness, along with white and black plastic mulches (120-μm-thick polyethylene) were recorded on the plants via a randomized complete block design with three replicate plots. We found significant benefits of all of the mulches during the 2021–22 season, as evidenced by 51% (P < 0.001), 31% (P = 0.0102), and 32% (P = 0.0048) more fruits for the 10-mm SHS, white plastic, and black plastic mulches, respectively, compared with the unmulched controls. Consequently, the total fruit yield per plant increased by 112% (P = 0.000), 71% (P < 0.001), and 83% (P < 0.001), under 10 mm SHS, white plastic, and black plastic mulches, respectively. Curiously, the field trial conducted in 2019 in an adjacent field did not reveal significant benefits of SHS, which we attribute partially to erratic rain showers and field heterogeneity. Taken together, this study and our previous work show that 10-mm-thick SHS mulch is optimal for boosting irrigation efficiency in regions where water is a limiting factor. Unlike plastic mulches, SHS biodegrades in <1 year and becomes a part of the sandy soil matrix, thereby obviating landfilling. Thus, the benefits of SHS exceed those of plastic mulches in terms of closing the yield gap and carbon footprint. These findings underscore the potential of SHS as a sustainable solution for growing plants in hot and dry arid regions in Saudi Arabia and globally.

Numerical investigation of effect of fill ratio and inclination angle on a U-shaped elliptical gravity heat pipe thermal performance

As electronic devices become increasingly compact, effective thermal management is crucial for performance. This study establishes a model of a U-shaped elliptical gravity heat pipe with dual heating ends and a single cooling end. Through computational fluid dynamics (CFD) simulations, the impacts of filling ratio and inclination angle on the thermal transfer capacity for the heat pipe were investigated. The results indicate that the evaporator surface temperature and thermal resistance of the heat pipe initially decrease and then increase with an increasing filling ratio. Within the inclination range of 10? to 90?, the evaporator surface temperature and thermal resistance gradually decrease. The optimal filling ratio is found to be 65%, and the optimal inclination angle is 90?. Furthermore, it was observed that higher heat input intensifies the effects of filling ratio and inclination angle affecting heat pipe thermal performance. These findings highlight the critical role of these parameters in optimizing heat pipe performance under varying heat inputs.

Characteristics of Energy Fluxes and Cold Frontal Effects on Energy Exchange over a Boreal Lake

Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable development. Based on eddy covariance measurements over Lake Vanajavesi in southern Finland, characteristics of energy fluxes and cold frontal effects on energy exchange were investigated. The lake acted as a heat sink in spring and summer and a heat source in winter. The latent heat flux reached its minimum value in the morning and peaked in the afternoon. The diurnal variation of sensible heat flux was opposite to that of latent heat flux. Impact factors for the sensible heat flux were mainly the lake-air temperature difference and the product of lake-air temperature difference and wind speed. The latent heat flux was mainly affected by the vapor pressure deficit and the product of vapor pressure deficit and wind speed. The annual mean values of bulk transfer coefficients for momentum, heat, and water vapor were 1.98 × 10−3, 1.62 × 10−3, and 1.31 × 10−3, respectively. Bulk transfer coefficients for heat and water vapor were not equal, indicating that the parameterization of energy exchange in numerical models, where the assumption that the heat coefficient equals the water vapor coefficient needs improvement. During the ice-free season, cold fronts resulted in 28 sensible heat pulses and 17 latent heat pulses, contributing to 50.59% and 34.89% of sensible and latent heat exchange in Lake Vanajavesi. These results indicate that cold fronts significantly impact the surface energy budget and evaporation over lakes.

Additive Manufacturing of a Frost-Detection Resistive Sensor for Optimizing Demand Defrost in Refrigeration Systems.

This article presents the development of a resistive frost-detection sensor fabricated using Fused Filament Fabrication (FFF) with a conductive filament. This sensor was designed to enhance demand-defrost control in industrial refrigeration systems. Frost accumulation on evaporator surfaces blocks airflow and creates a thermal insulating barrier that reduces heat exchange efficiency, increasing energy consumption and operational costs. Traditional timed defrosting control methods can mitigate these effects but often lead to inefficiencies due to their inability to align with actual frost accumulation, which can vary according to system and environmental conditions. Frost-detection sensors aim to solve this problem by acting as a tool to support defrosting control. A series of tests were conducted to evaluate the sensor's performance in detecting frost under controlled conditions on a heat exchanger (HX). The sensor reliably detected frost in all cases, demonstrating its effectiveness in real-time frost detection. The sensor measurements were validated by comparison with results obtained through a computer vision method, confirming its reliability. It was also found that the sensor can detect temperature changes. This advancement in sensor technology highlights the potential of additive manufacturing to provide cost-effective, customizable, replicable, and compact sensor designs, contributing to improved system performance and energy efficiency in refrigeration systems.

Surface wettability governs brine evaporation and salt precipitation during carbon sequestration in saline aquifers: Microfluidic insights.

Carbon sequestration in deep saline aquifers is a promising strategy for reducing atmospheric CO2 emissions. However, salt precipitation triggered by the evaporation of formation brine into injected supercritical CO2 can cause injectivity and containment issues in near-wellbore regions. Predicting the distribution of precipitated salts and their impact on near-wellbore properties remains challenging. This study investigates the influence of surface wettability on CO2-induced halite precipitation and growth within hydrophilic and hydrophobic microfluidic chips designed to mimic rock-structure porous geometries. A series of high-pressure brine-CO2 flow experiments, direct microscopic observations, and detailed image processing were conducted to explore how substrate wettability affects salt precipitation. The experiments show that wettability markedly controls residual brine relocation, film flow movement, solute consumption, and salt formation. Tracking halite precipitation dynamics revealed distinct crystal formation signatures: hydrophilic chips exhibited irregular, larger aggregation patches, while the hydrophobic network showed more numerous, smaller, and limited aggregations. Large individual crystals were observed in both chips, with a notable dominance in the hydrophobic one. Crystallization dynamics varied, with nucleation and growth occurring earlier, progressing faster, and forming bulkier aggregates in the hydrophilic chip. Despite these differences, the three identified temporal stages of brine evaporation and halite surface coverage were comparable. Spatial analysis along the chips indicated that crystal aggregation properties, such as size and distribution, were position-dependent, with hydrophilic chips exhibiting greater probabilistic variability. These observations underscore the impact of surface wettability on salt precipitation through brine accessibility and capillarity, with implications for mitigating and remediating salt issues in saline aquifers.

Evaluation of the Maximum Evaporation and the Priestley‐Taylor Models for Inland Waterbodies

AbstractThe Priestley‐Taylor (PT) model is a classic model of potential evaporation of terrestrial and marine surfaces. It is now recognized that the Bowen ratio (β) implicit in the PT model is too sensitive to temperature. The model also requires the surface net radiation (Rn) as input even though Rn is not an independent external forcing. The maximum evaporation model (MEM) proposed by Yang and Roderick (2019, https://doi.org/10.1002/qj.3481) is a potential candidate for replacing the PT model. Past studies have evaluated the MEM for land ecosystems and for the global ocean. This study represents the first evaluation of the MEM for inland waterbodies. Results are based on eddy‐covariance observation at a large lake and at a small fishpond. Although there were complex error structures and error compensation patterns among its intermediate variables, the MEM was able to reproduce the observed monthly (R2 > 0.95) and interannual variability (R2 > 0.78) in the lake latent heat flux. A key assumption of the MEM, that the incoming and outgoing longwave radiation is coupled, was a reasonable approximation at both the monthly and the annual time scale for the large lake and at the monthly time scale for the small fishpond. This assumption allows the MEM to treat Rn as an intermediate variable instead of a prescribed forcing. These results support the MEM as an alternative to the PT model at locations where Rn measurements are not available. In situations where Rn data is available, a revised PT model with reduced β temperature sensitivity is recommended.

An Observation‐Based Estimate of Atlantic Meridional Freshwater Transport

AbstractMeridional freshwater transport (MFT) in the Atlantic Ocean (Atlantic meridional freshwater transport (AMFT)) plays a vital role in the Atlantic Ocean circulations, but an accurate estimate of AMFT time series remains challenging. This study uses an indirect approach that combines ocean salinity, surface evaporation and precipitation observations to derive AMFT and its uncertainty by solving the ocean freshwater budget equation. Climatologically, AMFT is southward between 18.5°S and 34.5°S, but northward from 18.5°S to 66.5°N. AMFT also shows substantial inter‐annual variability with a clear separation at ∼40°N and is more coincident with the Atlantic Meridional Overturning Circulation (AMOC) at 26°N than 47°N across latitudes. The derived time series indicates that throughout the Atlantic Ocean, there is a positive trend in the AMFT from 2004 to 2020, resulting in an AMFT convergence in the tropical Atlantic and an AMFT divergence in the subtropical North Atlantic.

Laser melting, evaporation, and fragmentation of nanoparticles: Experiments, modeling, and applications

This review examines the processes of laser heating, melting, evaporation, fragmentation, and breakdown of metal nanoparticles, as well as the dependences and values of the threshold laser parameters that initiate these processes. Literature results are analyzed from experimental studies of these processes with gold, silver, and other nanoparticles, including laser surface melting and evaporation of nanoparticles and Coulomb fragmentation of nanoparticles by ultrashort laser pulses. A theoretical model and description of the thermal mechanisms of mentioned processes with metal (solid) nanoparticles in a liquid (solid) medium, initiated by the action of laser pulses with the threshold fluences, are presented. Comparison of the obtained results with experimental data confirms the accuracy of the model and makes it possible to use them to evaluate the parameters of laser thermal processing of nanoparticles. Applications of the processes include the laser melting, reshaping, and fragmentation of nanoparticles, the formation of nanostructures and nanonetworks, the laser processing of nanoparticles located on substrates, and their cladding on surfaces in various laser nanotechnologies. The use of laser ignition, combustion, and incandescence of nanoparticles is discussed, as is the use of nanoparticle-triggered laser breakdown for spectroscopy. These laser processes are used in photothermal nanotechnologies, nanoenergy, laser processing of nanoparticles, nonlinear optical devices, high-temperature material science, etc. In general, this review presents a modern picture of the state of laser technology and high-temperature processes with nanoparticles and their applications, being focused on the latest publications with an emphasis on recent results from 2021–2024.

Examination of Oxide Formation in Oxidation of Inconel 600 and 625 at High Temperatures Using Phase Diagrams

Effects of main and trace elements on the formation of oxide in the oxidation behavior of Inconel 600 and 625 were investigated in this study using various calculated phase diagrams. After the isothermal oxidation tests at 1000 and 1100 °C, Nickel 201 for comparison showed significant growth of an oxide layer corresponding to NiO, and the NiO layer consisted of oxide crystals with both equiaxed and columnar shapes. As the temperature increased, the growth of the oxide layer proceeded mainly through columnar crystals. On the other hand, Inconel 600 and 625 showed relatively thin oxide layers, which were confirmed to be mainly composed of Cr2O3. The Cr2O3 layer was composed of equiaxed fine crystals. In the case of Inconel 625, an intermediate layer was formed at the interface between Cr2O3 and the base metal. It was found that the surface segregation of Cr as the main alloying element influenced the formation of the oxide layer of two Inconel alloys, and that some elements disappeared from the base metal near the surface due to continuous surface segregation and vaporization. On the other hand, even some elements with trace amounts showed strong surface segregation and contributed to the formation of oxide layer.

High-Performance Silicone Sponge Evaporators with Low Thermal Conductivity for Long-Term Solar Interfacial Evaporation and Freshwater Harvesting.

Solar interfacial evaporation (SIE) has emerged as a highly promising approach for sustainable freshwater harvesting. However, maintaining a stable evaporation rate and achieving a high freshwater yield in high-salinity brines remain a significant challenge. In this study, we present the development of silicone sponge-based evaporators with a "free-salt" structure, designed to enhance the efficiency of SIE and freshwater collection. These evaporators, designated as PSS@Fe3O4/CNTs, were fabricated by grafting durable silicone onto a silicone sponge framework, followed by the incorporation of Fe3O4 nanoparticles and carbon nanotubes. The unique combination of exceptional photothermal properties and a controlled yolk-shell structure with low thermal conductivity enabled the PSS@Fe3O4/CNT evaporators to sustain a stable evaporation rate of 1.87 kg m-2 h-1 in real seawater over 200 h of continuous operation under 1 sun illumination. Importantly, no salt accumulation was observed on the evaporator surfaces, even when exposed to highly concentrated brines. In a closed system equipped with a condenser, these evaporators achieved freshwater production rates of 14.5 and 11.8 kg m-2 over 10 h from 10 and 20 wt % NaCl solutions, respectively, under 1 sun illumination. These values correspond to normalized production rates of 1.45 and 1.18 kg m-2 h-1, showcasing the consistent and efficient performance of the evaporators across varying salinity levels. Beyond salt rejection, the PSS@Fe3O4/CNT evaporators also demonstrated the ability to effectively remove various heavy metal ions (e.g., Cu2+ and Zn2+) and organic pollutants from contaminated water. This work provides valuable insights into innovative evaporator designs for efficient freshwater production from seawater and wastewater.

Machine learning and molecular dynamics simulations aided insights into condensate ring formation in laser spot welding

Condensate ring formation can be used as a benchmark in welding processes to assess the efficiency and quality of the weld. Condensate formation is critical as the resulting condensate settles into the powder thereby altering the quality of unconsolidated powder. This study investigates the intricate relationship between alloy composition, vapor pressure, and condensate ring thickness as seen in a two-dimensional micrograph. To study the process, laser spot welding was performed on 9 different alloys, and the inner spot weld diameter along with the condensate ring formation was studied. Leveraging machine learning models, experimental observations, and molecular dynamics simulations, we explore the fundamental factors governing condensate ring formation. The models, adept at predicting weld spot diameter and condensate ring thickness, identify laser power as a primary determinant for weld spot diameter followed by physical properties like hardness and density. Conversely, for condensate ring thickness, vapor pressure and melting point descriptors consistently emerge as paramount, as validated across all models. Molecular dynamics simulations on Ni-Cr alloys elucidate the vaporization dynamics, confirming the role of vapor pressure in governing surface vaporization. Our findings underscore the pivotal influence of vapor pressure and melting point descriptors in condensate ring formation. The convergence of machine learning predictions and simulation insights elucidates the dominance of these descriptors, offering crucial insights into alloy design strategies to minimize condensate ring formation in laser welding processes.

Highly efficient and salt resistant solar interface evaporator based on pressed wood flour with multi-level pores

Interfacial solar steam generation has garnered significant attention as an eco-friendly and sustainable technology for desalination and wastewater purification. Nevertheless, in challenging conditions such as strong brine and high-intensity settings, both the evaporation efficiency and the service life of the solar evaporator are inevitably diminished due to salt accumulation on the surface of interfacial solar evaporators. Here, a platelike evaporator that features high water evaporation rate in brine without salt accumulation is developed by rational design of polydopamine-coated wood powder with a hierarchical pore structure. This evaporator not only exhibits high water evaporation rate of 2.299 kg m−2 h−1 along with 155.4 % solar-to-steam conversion efficiency under 1 sun illumination, but also deliver exceptional salt accumulation resistance even in 20 wt% brine. With the advantages of a high light absorption rate, easy preparation process, and low cost, this evaporator shows promising potential in the field of solar steam generation and seawater desalination.