Experimental study of relationship between average isotopic fractionation factor and evaporation rate

Isotopic fractionation is the basis of tracing the water cycle using hydrogen and oxygen isotopes. Isotopic fractionation factors in water evaporating from free water bodies are mainly affected by temperature and relative humidity, and vary significantly with these atmospheric factors over the course of a day. The evaporation rate （E） can reveal the effects of atmospheric factors. Therefore, there should be a certain functional relationship between isotopic fractionation factors and E. An average isotopic fractionation factor （ t~＊ ） was defined to describe isotopic differences between vapor and liquid phases in evaporation with time intervals of days. The relationship between or＊ and E based on the isotopic mass balance was investigated through an evaporation pan experiment with no inflow. The experimental results showed that the isotopic compositions of residual water were more enriched with time; tr＊ was affected by air temperature, relative humidity, and other atmospheric factors, and had a strong functional relation with E. The values of 0~＊ can be easily calculated with the known values of E, the initial volume of water in the pan, and isotopic compositions of residual water.

EVAPORATION RATE OF SnS FROM SLAGS

Under inert atmospheres and 1473 K,the evaporation rate of SnS from SnO-FeO- SiO_2 and SnO-FeO-CaO-SiO_2 slags mixed with FeS was investigated by measuring the weight Ioss and composition of samples.The experimental results show that dur- ing sulfide fuming process the evaporation of SnOfrom slags is negligible in comparison with that of SnS.Addition of CaOto slags can enhance the evaporation rate of SnS.The differential rate equation of evaporation may be expressed as: -d(%Sn)/dt=k(%Sn)(%S) where,the apparent rate constant k was found to be 4.20×10^(-3) for SnO-FeO-CaO- SiO_2 system and 2.88×10^(-3) for SnO-FeO-SiO_2 system,respectively.

Amodified numerical model for moisture-salt transport in unsaturated sandy soil under evaporation

Soil salinization,caused by salt migration and accumulation underneath the soil surface,will corrode structures.To analyze the moisture-salt migration and salt precipitation in soil under evaporation conditions,a mathematical model consisting of a series of theoretical equations is briefly presented.The filling effect of precipitated salts on tortuosity factor and evaporation rate are taken into account in relevant equations.Besides,a transition equation to link the solute transport equation before and after salt precipitation is proposed.Meanwhile,a new relative humidity equation deduced from Pitzer ions model is used to modify the vapor transport flux equation.The results show that the calculated values are in good agreement with the published experimental data,especially for the simulation of volume water content and evaporation rate of Toyoura sand,which confirm the reliability and applicability of the proposed model.

Evaluating the soil evaporation loss rate in a gravel-sand mulching environment based on stable isotopes data

In order to cope with drought and water shortages,the working people in the arid areas of Northwest China have developed a drought-resistant planting method,namely,gravel-sand mulching,after long-term agricultural practices.To understand the effects of gravel-sand mulching on soil water evaporation,we selected Baifeng peach(Amygdalus persica L.)orchards in Northwest China as the experimental field in 2021.Based on continuously collected soil water stable isotopes data,we evaluated the soil evaporation loss rate in a gravel-sand mulching environment using the line-conditioned excess(lc-excess)coupled Rayleigh fractionation model and Craig-Gordon model.The results show that the average soil water content in the plots with gravel-sand mulching is 1.86%higher than that without gravel-sand mulching.The monthly variation of the soil water content is smaller in the plots with gravel-sand mulching than that without gravel-sand mulching.Moreover,the average lc-excess value in the plots without gravel-sand mulching is smaller.In addition,the soil evaporation loss rate in the plots with gravel-sand mulching is lower than that in the plots without gravel-sand mulching.The lc-excess value was negative for both the plots with and without gravel-sand mulching,and it has good correlation with relative humidity,average temperature,input water content,and soil water content.The effect of gravel-sand mulching on soil evaporation is most prominent in August.Compared with the evaporation data of similar environments in the literature,the lc-excess coupled Rayleigh fractionation model is better.Stable isotopes evidence shows that gravel-sand mulching can effectively reduce soil water evaporation,which provides a theoretical basis for agricultural water management and optimization of water-saving methods in arid areas.

Chemical Scissors Tailored Nano‑Tellurium with High‑Entropy Morphology for Efficient Foam‑Hydrogel‑Based Solar Photothermal Evaporators

The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy concerns.However,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface structures.Herein,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic liquid.Anions,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk Te.The resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light absorption.We also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun irradiation.Furthermore,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.

Mn evaporation and denitrification behaviors of molten Mn steel in the vacuum refining with slag process

Considering the precise composition control on the vacuum refining of high-Mn steel, the behaviors of both Mn evaporation and nitrogen removal from molten Mn steel were investigated via vacuum slag refining in a vacuum induction furnace. It was found that the reaction interfaces of denitrification and Mn evaporation tend to migrate from the surface of slag layer to the surface of molten steel with the gradual exposure of molten steel during the vacuum slag refining process. Significantly, compared with the experimental group without slag addition, the addition of slag into steel can result in a lower Mn evaporation rate constant of 0.0192 cm·min~(-1) at 370 Pa, while the denitrification rate is almost not affected. Besides, the slag has a stronger inhibitory effect on Mn evaporation than the reduced vacuum pressure. Moreover, the inhibitory effect of the slag layer on Mn evaporation can be weakened with the increase of the initial Mn content in molten steel. The slag layer can work as an inhibitory layer to reduce the Mn evaporation from molten steel, the evaporation reaction of Mn mainly proceeds on the surface of the molten steel. This may be attributed to the Mn mass transfer coefficient for one of reaction at steel/slag interface, mass transfer in molten slag, and evaporation reaction at slag/gas interface is lower than that of evaporation reaction at steel/gas interface. The introduction of slag is proposed for both denitrification and manganese control during the vacuum refining process of Mn steels.

An Experimental Validation Study on Ferrofuid Evaporation

The current research on the evaporation of ferrofuids mainly focuses on the characterization of ultra-low vapor pressure ferrofuids in vacuum and the theoretical analysis of the evaporation process.Few studies have focused on the experimental validation of the proposed evaporation rate equations and on the comparison of the diferences in ferrofuid evaporation.In this study,based on the Bolotov’s model,an evaporation rate equation is deduced from the experimental model.The experimental study included a comparison of the evaporation,magnetic particle volume fraction,temperature,height of the fuid surface from the outlet,and magnetic feld of a kerosene-based ferrofuid and its base carrier liquid.The prepared sample was evaporated in a test tube,and the evaporation rate was calculated by measuring the weight loss of the sample.The experimental results show that the evaporation rate of the base carrier liquid is higher than that of the ferrofuid.The smaller the volume fraction of the magnetic particles,the greater the evaporation rate.The magnetic particles play a key role in preventing evaporation of the base liquid.The higher the temperature,the smaller the deviation of the evaporation rate from the predicted value.The evaporation rates obtained by the two control groups at the height of the fuid surface from the outlet were lower than the predict value.The magnetic feld had a certain promotional efect on the evaporation of the ferrofuid.The experimental results were consistent with the results obtained using Bolotov’s model.This research validates Bolotov’s model and shows that the model is somewhat biased but still responds well to diferent variables.

Characteristic Research on Evaporated Explosive Film

The evaporation source of evaporated explosive was designed and improved based on the inherent specialties of explosive. The compatibility of explosives and addition agent with evaporation vessels was analyzed. The influence of substrate temperature on explosive was analyzed, the control method of substrate temperature was suggested. The influences of evaporation rate on formation of explosive film and mixed explosive film were confirmed. Optimum evaporation rate for evaporation explosive and the better method for evaporating mixed explosive were presented. The necessary characteristics of the evaporated explosive film were obtained by the research of the differences between the evaporated explosive and other materials.

Comparisons of Several Evaporation/Precipitation Datasets for the Bohai Sea Based on Salinity Simulation

Evaporation （E） rate and precipitation （P） rate are two significant meteorological elements required in the ocean baro- clinic modeling as external forcings. However, there are some uncertainties in the currently used E/P rates datasets, especially in terms of the data quality. In this study, we collected E/P rates data from ERA-40, NCEP/NCAR Reanalysis, HOAPS for the Bohai Sea and nine routine stations around Laizhou Bay, and made comparisons among them. It was found that the differences in E/P rates between land and sea are remarkable, which was due to the difference in underlying surfaces. Therefore, the traditional way of using E/P rates acquired on land directly at sea is not correct. Since no final conclusion has been reached concerning the net water transport between the Bohai Sea and the Yellow Sea, it is unfeasible to judge the adequacy of the four kinds of data by using the water budget equation. However, the E/P rates at ERA-40 sea points were considered to he the optimal in terms of temporal/spatial coverage and resolution for the hindcast of salinity variation in the Bohai Sea. Besides, using the 3-D hydrodynamic model HAMSOM （HAMburg Shelf Ocean Model）, we performed numerical experiments with different E/P datasets and found that the E/P rates at sea points from ERA-40 dataset are better than those from NCEP/NCAR Reanalysis dataset. If NCEP/NCAR Reanalysis E/P rates are to be used, they need to be adjusted and tested prior to simulation so that more close-to-reality salinity values can be reproduced.

Experimental Study for the Cementation Effect of Dust Soil by Using Soybean Urease

Dust is an environmental and health hazard.In this study,a new technology for dust suppressant is introduced using soybean urease with an optimal cementing solution.Calcium carbonate is produced by soybean urease and cementing solution,which bonds the soil particles towards a dust suppressant.A laboratory wind tunnel test is carried out to examine its effectiveness and discover possible optimization solutions.Several factors,including soybean meal concentration,cementing solution concentration,and volume of solution per unit area,are examined to quantify their influences on soil transport mass,evaporation ratio,evaporation rate,surface strength,water retention ratio,and infiltration rate of soil treated by different dust suppressants.Field tests are conducted to explore the performance of this method in the natural environment.The results show that compared with other dust suppressants,the optimized soybean urease has the smallest evaporation rate,a moderate infiltration rate,the largest water retention ratio and surface strength.The indexes of soybean urease for dust suppressant are found to be better than traditional materials.In the natural environment,soybean urease has a stronger anti-disturbance ability.This study concludes that soybean urease dust suppressant has great application potential as a cheap and green method.

Variable hydrological effects of herbs and shrubs in the arid northeastern Qinghai-Tibet Plateau,China

This study aims to assess the hydrological effects of four herbs and four shrubs planted in a selfestablished test area in Xining Basin of northeastern Qinghai-Tibet Plateau, China. The RainfallIntercepting Capability(RIC) of the herbs and shrubs was evaluated in rainfall interception experiment at the end of the third, fourth and fifth month of the growth period in 2007. The leaf transpiration rate and the effects of roots on promoting soil moisture evaporation in these plants were also assessed in transpiration experiment and root-soil composite system evaporation experiment in the five month's growth period. It is found that the RIC of the fourstudied herbs follows the order of E. repens, E. dahuricus, A. trachycaulum and L. secalinus; the RIC of the four shrubs follows the order of A. canescens, Z. xanthoxylon, C. korshinskii and N. tangutorum. The RIC of all the herbs is related linearly to their mean height and canopy area(R^2 ≥ 0.9160). The RIC of all the shrubs bears a logarithmic relationship with their mean height(R^2 ≥ 0.9164), but a linear one with their canopy area(R^2 ≥ 0.9356). Moreover, different species show different transpiration rates. Of the four herbs, E. repens has the highest transpiration rate of 1.07 mg/(m^2·s), and of the four shrubs, A. canescens has the highest transpiration rate(0.74 mg/(m^2·s)). The roots of all the herbs and shrubs can promote soil moisture evaporation. Of the four herbs, the evaporation rate of E. repens root-soil composite system is the highest(2.14%), and of the four shrubs,the root-soil composite system of A. canescens has the highest evaporation rate(1.41%). The evaporation rate of the root-soil composite system of E. dahuricus and Z. xanthoxylon bears a second-power linear relationship with evaporation time(R^2 ≥ 0.9924). The moisture content of all the eight root-soil composite systems decreases exponentially with evaporation time(R^2 ≥ 0.8434). The evaporation rate and moisture content of all the plants' root-soil composite systems increases logarithmically(R^2 ≥ 0.9606) and linearly(R^2 ≥ 0.9777) with root volume density. The findings of this study indicate that among the four herbs and four shrubs, E. repens and A. canescens possess the most effective hydrological effects in reducing the soil erosion and shallow landslide in this region.

Constructing central hollow cylindrical reduced graphene oxide foams with vertically and radially orientated porous channels for highly efficient solar-driven water evaporation and purification

Although solar steam generation is an eco-friendly approach for desalinating seawater and purifying wastewater,there are still issues on how to improve the efficiency of solar energy utilization and accelerate the water and heat transport inside the solardriven water evaporators.Herein,we design a central hollow cylindrical reduced graphene oxide(RGO)foam with vertically and radially orientated channels as a solar steam generation device for efficient water evaporation and purification.The vertically aligned porous channels accelerate upward transport of water to the top evaporation surface,while the radially aligned porous channels facilitate water transport and heat transfer along the radial directions for fully utilizing the heat accumulated inside the central cylindrical hole of the foam.The central hole of the foam plays a highly positive role in accumulating more heat for accelerating the water evaporation,the newly generated inner sidewall resulted from the central hole can gain extra thermal energy from surrounding environment in the same way as the outer sidewall of the foam due to the surface cooling effect of the water evaporation.As a result,the vertically and radially aligned RGO foam evaporator with central hollow cylinder achieves a high solar steam generation rate of 2.32 kg·m^(−2)·h^(−1)with an exceptional energy conversion efficiency of 120.9%under 1-sun irradiation,superior to the vertically aligned RGO foam without the central hole(1.83 kg·m^(−2)·h^(−1),96.9%)because of the enhanced water and heat transfer inside the porous channels,the efficient utilization of environmental energy.

Experiment on Vaporization of Jet into Cross-Flow

The injection characteristics of the main fuel nozzle,which is widely applied in advanced lean-premixed-prevaporized(LPP)low-emission combustors,can be simplified as the atomization and vaporization processes of a jet into cross-flow.In this study,a nozzle with a diameter of 0.4 mm is designed and processed through the heating of the inlet air,and the vaporization characteristics are investigated.The optical measurement and cyclone separation methods are separately used to investigate the evaporation rate of a jet into cross-flow.Experimental results show that the fuel evaporation rate in cross-flow is mainly affected by the Weber number(We),equivalent ratio(φ),momentum rate of fuel to air(q),and air temperature.In addition,the inlet temperature is a crucial factor for the evaporation ratio of a jet into cross-flow.The evaporation results measured by two different methods in the same cross-flow are very close to each other with a deviation within 10%.

A new stationary droplet evaporation model and its validation

The liquid droplet evaporation character is important for not only combustion chamber design process but also high-accuracy spray combustion simulation. In this paper, the suspended droplets＇ evaporation character was measured in a quiescent high-temperature environment by micro high-speed camera system. The gasoline and kerosene experimental results are consistent with the reference data. Methanol, common kerosene and aviation kerosene droplet evaporation characteristics, as well as their evaporation rate changing with temperature, were obtained. The evaporation rate experimental data were compared with the prediction result of Ranz-Marshall boiling temperature model（RMB）, Ranz-Marshall low-temperature model（RML）, drift flux model（DFM）, mass analogy model（MAM）, and stagnant film model（SFM）. The disparity between the experimental data and the model prediction results was mainly caused by the neglect of the natural convection effect, which was never introduced into the droplet evaporation concept. A new droplet evaporation model with consideration of natural convection buoyancy force effect was proposed in this paper. Under the experimental conditions in this paper, the calculation results of the new droplet evaporation model were agreed with the experimental data for kerosene, methanol and other fuels, with less than 20% relative deviations. The relative deviations between the new evaporation model predictions for kerosene and the experimental data from the references were within 10%.

Towards highly salt-rejecting solar interfacial evaporation:Photothermal materials selection,structural designs,and energy management

With the development of the industry,water pollution and shortage have become serious global problems.Owing to the abundance of seawater storage on earth,efficient solar-driven evaporation is a promising approach to relieve the freshwater shortage.The solar-driven evaporation has attracted tremendous attention due to its potential application in the seawater desalination and wastewater treatment fields.Also,the solar-driven evaporation efficiency can be enhanced by designing both solar absorbers and structures.Up to now,many strategies have been explored to achieve high solar-driven evaporation efficiency,mainly including the selection of photothermal conversion materials and structure optimization.In this review,the solar absorbers,structural designs,and energy management are proposed as the keys for high performance solar-driven evaporation systems.We report four kinds of solar absorbers based on different photothermal conversion mechanisms,substrate structure designs,and energy management methods for the purpose to achieve high conversion efficiency.And we also systematically investigate the available salt-rejections strategies for seawater desalination.This review aims to summarize the current development of efficient solar-driven evaporation systems and provide insights into the photothermal conversion materials,structural designs,and energy management.Finally,we propose the perspectives of the salt-rejection technologies for seawater desalination.

Thick exchange layer evaporation model with natural convection effect and evaporation experimental study for multicomponent droplet

In order to investigate the high-temperature evaporation characteristics of multicomponent liquid fuel,three kinds of blended fuel:n-heptane/n-decane/RP-3 aviation kerosene-ethanol were experimentally studied with and without forced convection.Further,based on zerodiffusion and infinite diffusion concept,this study expanded Thick Exchange Layer evaporation model with Natural Convection effect(NC-TEL)to multicomponent liquid fuels.The experimental results show that the droplet evaporation rate increases significantly with the increase of ambient temperature.Higher temperature leads to more significant relationships between the composition ratio and the evaporation rate.The effect of forced convection is not obviously under the circumstance in this paper.Then,the evaporation models were validated by experimental data.In general,the new NC-TEL model behaves better than the Ranz-Marshall(R-M)model,and the prediction accuracy at high temperature is improved by 8%to 35%.In lower temperature conditions,the prediction of zero-diffusion NC-TEL model is better than the infinite diffusion NC-TEL model.In high-temperature conditions,for n-heptane-ethanol droplet,the predictions of NC-TEL model are accurate,but for n-decane/RP-3 aviation kerosene-ethanol,the predictions are lower than experimental results.This may be caused by the micro-explosion phenomenon and the Marangoni phenomenon.