Increase In Evaporation Rate Research Articles

Investigating a microbial approach to water conservation: Effects of Bacillus subtilis and Surfactin on evaporation dynamics in loam and sandy loam soils

Semi-arid regions faced with increasingly scarce freshwater resources must manage competing demands in the food-energy-water nexus. A possible solution modifies soil hydrologic properties using biosurfactants to reduce evaporation and improve water retention. In this study, two different soil textures representative of agricultural soils in Kansas were treated with a direct application of the biosurfactant, Surfactin, and an indirect application via inoculation of Bacillus subtilis. Evaporation rates of the wetted soils were measured when exposed to artificial sunlight (1000 W/m2) and compared to non-treated control soils. Experimental results indicate that both treatments alter soil moisture dynamics by increasing evaporation rates by when soil moisture is plentiful (i.e., constant rate period) and decreasing evaporation rates by when moisture is scarce (i.e., slower rate period). Furthermore, both treatments significantly reduced the soil moisture content at which the soil transitioned from constant rate to slower rate evaporation. Out of the two treatments, inoculation with B. subtilis generally produced greater changes in evaporation dynamics; for example, the treatment with B. subtilis in sandy loam soils increased constant rate periods of evaporation by 43% and decreased slower rate evaporation by 49%. In comparing the two soil textures, the sandy loam soil exhibited a larger treatment effect than the loam soil. To evaluate the potential significance of the treatment effects, a System Dynamics Model operationalized the evaporation rate results and simulated soil moisture dynamics under typical daily precipitation conditions. The results from this model indicate both treatment methods significantly altered soil moisture dynamics in the sandy loam soils and increased the probability of the soil exhibiting constant rate evaporation relative to the control soils. Overall, these findings suggest that the decrease in soil moisture threshold observed in the experimental setting could increase soil moisture availability by prolonging the constant rate stage of evaporation. As inoculation with B. subtilis in the sandy loam soil had the most pronounced effects in both the experimental and simulated contexts, future work should focus on testing this treatment in field trials with similar soil textures.

All-inorganic robust absorber for high-sun solar steam generation and solvent recovery

The mechanical and chemical stability of the light-absorber creates a limitation of the STS applications, especially in harsh operating conditions such as high temperature or aggressive solvents environment. The current study addresses the issue by proposing a highly stable and durable light absorber based on the gold nanoparticles (Au NPs) immobilized on the mesoporous silica-covered glass fiber (MSGF). Mesoporous silica coating improves the attachment of Au NPs to the fiber surface, while simultaneously increasing specific surface area. The synthesis parameters of the mesoporous silica layer and the Au NPs were adjusted to obtain favorable morphology, resulting in a 16.7% increase in the total solar weighted absorptance. The STS system based on two-dimensional Au-MSGF achieved the highest evaporation rate of 1.22 kg·m −2 ·h -1 under 1 sun illumination at 20 °C and relative humidity of 40%. Furthermore, the thermal stability and durability of glass fiber allowed the application of Au-MSGF for the STS at sunlight illumination intensities as high as 50-suns without any visible or performance degradation over extended periods. The inertness of the Au-MSGF plays an important role in the solvent recovery applications of the STS system. It was found that the hydrophobic coating of the light absorber improves the performance of the STS system for non-polar solvent recovery. The results indicate a significant (over 100% as compared to the evaporation in the darkroom) evaporation rate increase of octane and decane in the STS system operating under 1 and 2 suns, making them suitable for the STS solvent recovery. • A highly stable all-inorganic absorber is developed for STS generation. • SiO 2 coating increases the surface area of glass fiber. • High sun STS generation is possible up to 50 Sun. • Solar induced solvent recovery using STS is successfully demonstrated. • STS-solvent recovery is efficient for solvents with low p v .

Transient cooling performance of R134a flash-evaporation spray enhanced by cold air jet: A novel heat transfer enhancement method in laser dermatology

Nevus of Ota is a dermal hyperplastic pigmented disease with a morbidity rate of 0.1–0.6% in the Asian population. Laser surgery with the assistance of cryogen spray cooling (CSC) is a potential clinical treatment for nevus of Ota. However, for Asians with high melanin content, it is necessary to enhance cooling capability without the increment of refrigerant amount. In this study, a R134a flash-evaporation cryogen spray cooling coupled with cold air jet (CSC-CAJ) was developed to improve the cooling capacity. Epoxy resin was employed as a skin phantom to investigate the heat transfer characteristics of CSC-CAJ with different air jet parameters. Air jet parameters of CSC-CAJ are recommended to be Ta = -7 ℃, Va = 3 m3/h Za = 10 mm and Φa = 30°. Compared to CSC, CSC-CAJ could reduce the minimum surface temperature from -39 to -42.1 ℃, and the average value of convective heat transfer coefficient (h) of CSC-CAJ could increase from 8 to 12.9 W/(m2·k) or 61.3% for the recommended parameters. The liquid film residence time (τ) decreases from 301 to 234 ms or 23.3%. In addition, based on the visualization observation and surface heat transfer measurement, the frost formation phenomenon on the surface and the heat transfer enhancement mechanisms are well understood. Four modes, including Leidonfrost mode, no runoff mode, runoff mode and evaporation mode, are proposed to describe the four stages of CSC-CAJ. A non-dimensional correlation of normalized Nusselt number (Nu*) and time (t*) is summarized. The primary heat transfer enhancement mechanism of CSC-CAJ is found to be the increase in cryogen evaporation rate and the ratio of heat removal from the phantom surface to phase change latent heat.

Increase in Leidenfrost point via plasma-activated water

We exploit plasma-activated water to increase the Leidenfrost point for application in spray cooling. Due to the presence of reactive oxygen and nitrogen species in the plasma-activated water, compared to deionized (DI) water, we observe up to an 18% increase in the solution density and up to 21% reduction in the surface tension. This gives rise to a significant increase in evaporation rate using the plasma-activated water compared to DI water and also leads to a shift in Leidenfrost point. Specifically, in the nucleate and transition boiling regimes, we observe a considerable reduction in the surface temperature when the plasma-activated water droplet is impinging on the heated plate as compared to the DI water droplet, i.e., up to 220%. We further demonstrate the practicality of plasma-activated water droplets as a viable alternative to replace DI water droplets in spray cooling through a commonly used graphene–epoxy surface coating enhancement technique. With the plasma-activated water droplet, we show a further reduction in the surface temperature of the heated plate by up to 11% as compared to the DI water droplet. Given that plasma-activated water can be easily produced and its bacterial inactivation characteristic can circumvent bacteria growth, these promising results highlight its potential applicability to replace DI water as a coolant in practical cooling systems.

Performance evaluation of using evacuated tubes solar collector, perforated fins, and pebbles in a solar still - experimental study and CO2 mitigation analysis.

The combination of various methods of increasing evaporation rate can highly impact the performance of solar desalination. This investigation aims to find the impact of using evacuated tubes solar collector, perforated fins, and pebbles on the performance enhancement of a solar still. Simultaneously six-evacuated-tube solar collector to raise the evaporation rate of the system, the perforated fins to increase the heat transfer surface between water and absorber, and the immersed pebbles stone in the water to keep the high water temperature at low solar radiation were considered. The hourly and cumulative distillate output (DO) values are presented separately for the daytime and nighttime to provide extensive insight. The results indicate that on a sample day from the six months of experiments, which was in February 2019, the time for DO peak shifts from 1 to 3 p.m. Moreover, the temperature values for MSS experience almost 43 ℃ jumps on the peak and almost 19 ℃ increase on average compared to CSS. Furthermore, the cumulative DO in the daytime reaches from 2.515 to 6.662 L, while during the nighttime, an increase from 0.057 to 0.872 L is observed. Additionally, during the six months, the average DO jumps from 2.88 to 7.03 L, which means a significant enhancement of 144.1%. Moreover, the costs per liter of MSS and CSS are 0.0051 and 0.0056 dollars per liter, respectively. The net amount of CO2 reduction of MSS was improved by about 2.44 times higher than CSS.

Quantifying relative contributions of source waters from a subalpine wetland to downstream water bodies

AbstractSubalpine regions of the Canadian Rocky Mountains are expected to experience continued changes in hydrometeorological processes due to anthropogenically mediated climate warming. As a result, fresh water supplies are at risk as snowmelt periods occur earlier in the year, and glaciers contribute less annual meltwater, resulting in longer growing seasons and greater reliance on rainfall to generate runoff. In such environments, wetlands are potentially important components that control runoff processes, but due to their location and harsh climates their hydrology is not well studied. We used stable water isotopes of hydrogen and oxygen (δ2H and δ18O), coupled with MixSIAR, a Bayesian mixing model, to understand relative source water contributions and mixing within Burstall Wetland, a subalpine wetland (1900 m a.s.l.), and the larger Burstall Valley. These results were combined with climate data from the Burstall Valley to understand hydrometeorological controls on Burstall Wetland source water dynamics over spatiotemporal timescales. Our results show that the seasonal isotopic patterns within Burstall Wetland reflect greater reliance on snowmelt in spring and rainfall in the peak and post‐growing season periods. We found a substantial degree of mixing between precipitation (rain and snow) and stored waters in the landscape, especially during the pre‐growing season. These findings suggest that longer growing seasons in subalpine snow‐dominated landscapes put wetlands at risk of significant water loss and increased evaporation rates potentially leading to periods of reduced runoff during the peak‐ growing season and in extreme cases, wetland dry out.

Thermal performance enhancement in hot air and solar drying of pineapple slices with ultrasonic vibration

Hot air and solar drying are among the most popular preservation methods for fresh fruits. Ultrasonic technology could enable a faster dehydration rate at low temperatures, hence, preserving vitamins and nutrients in fruits. In this work, the application of ultrasonic vibration to pineapple drying was investigated. Experiments were conducted in hot air as well as direct solar dryers. The temperature in the hot air dryer was controlled at 60 °C, with an applied vibration frequency of 40 kHz. Three cycles of 10, 20, and 30 min with 1 min ultrasonic operation per interval were tested. The results showed that for the cycle of 10 min with 1 min vibration applied, the moisture content of pineapple slices was decreased from 87 to <13.7 %wb at a maximum evaporation rate of 49 g/h. Similar tests in the solar dryer proved to reduce the drying time from 3 to 2 days, with an increased evaporation rate of 10.6 g/h. Minimum specific energy consumption was realized by applying 1 min of ultrasonic vibration in a 10 min cycle with the solar dryer. Maximum thermal efficiency of over 63% was achieved with ultrasonic assisted solar drying.

Hydrochemical Study of the Southern Sector of the Al-Massab Al-Aam Canal Water, Southern Iraq

Al- Masab AL-Aam canal (or the Main Drain) is a vital strategic project in Iraq. It collects the drain water from the agricultural lands and drains to the Arabian Gulf via Shatt Al-Basra. Fifteen water samples were collected from different sites along the course of the Al- Masab Al-Aam canal southern sector extending from Nasiriyah Basra to evaluate the hydrochemical properties. The variation of the sediment’s texture along the southern sector was investigated. The results reflected that the sediment is characterized by the presence of sand, silt, and clay. It is noted that the amount of salt in the water increases during the summer when temperatures are rising, and consequently, the evaporation rate increases. Changes in the saturation index also continuously affect the dissolution and precipitation of minerals along the river. The results of the saturation index analysis showed that the relationship between sulfate concentration and mineral saturation coefficients tends to increase their solubility for most minerals. The importance of the research lies in knowing and identifying the factors causing the change in water quality through studying the hydrological and hydrochemical properties of water and comparing the results to find out the reasons for the increase and decrease in its concentrations along the study area.

Stacked Laser-Induced Graphene Joule Heaters for Desalination and Water Recycling

The global scenario of water shortage and pollution has necessitated the use of advanced water treatment and desalination technologies. Solar interfacial evaporation has shown promising results for clean water generation but depends on the sunlight intensity, which changes over time and climatic conditions. Furthermore, the solar-driven interfacial evaporation cannot operate in the dark and is susceptible to salt deposition. Here, we have explored the Joule heating effect in laser-induced graphene (LIG)-based Joule heaters (JHs) for interfacial water evaporation under different applied voltages. The effect of stacking of Joule heaters has been explored and found to give an enhanced evaporation rate with less spatial footprint and energy consumption. The evaporation rate in a single-layer LIG JH reached ∼5 kg·m–2·h–1 under the application of 10 V. The JH area and its stacking effect on evaporation rate, spatial footprint, and energy consumption were investigated. An increase in evaporation rate by seven times and reduction of electrical energy consumption by three times has been demonstrated by three levels of stacking compared to its equivalent triple-area LIG JH. The enhanced performance of the stacking configuration could be due to the enhanced heat transfer from the bottom JH to the upper JH, thermal concentration, and reduced thermal losses to the environment. The single-layer LIG JH also gave ∼2 kg·m–2·h–1 evaporation rate under natural sunlight and environmental conditions, showing potential for solar interfacial evaporation. The JHs also showed excellent resistance to salt deposition with self-salt-cleaning capability under the tested conditions. These compact stacked JH systems could be integrated with renewable energy, which can be operated in the presence and absence of sunlight. Such compact JH systems with a lesser spatial footprint, enhanced evaporation rate, and reduced energy requirement can help in providing constant water evaporation for various applications.

Evaporation Characteristics of Lubricant/Gasoline Blending Oil Film Under Different Thermal Radiations

Abstract The evaporation and pro-ignition characteristics of the lubricating oil blending in the cylinder can bring a super knock for the high-efficiency gasoline engine. The evaporation characteristics of the lubricant/gasoline blending oil film were investigated experimentally under different thermal radiative heat flux, film thickness, and carrier material in a radiation device. The blending ratios of lubricant/gasoline oil film changed from 0% to 15%. Three stages of the blending oil film evaporation process were observed according to the different evaporation rates, namely, transient heating, equilibrium evaporation, and evaporation gel. During the transient heating stage, with the increase of gasoline blending ratio, oil film thickness, and radiative heat flux, the evaporation rate increases, while the evaporation rate decreases in the equilibrium evaporation stage. The evaporation rates in transient heating stage and equilibrium evaporation stages are reasonably predicted by using the proposed relationship model.

Multi-scale temporal analysis of evaporation on a saline lake in the Atacama Desert

Abstract. We investigate how evaporation changes depending on the scales in the Altiplano region of the Atacama Desert. More specifically, we focus on the temporal evolution from the climatological to the sub-diurnal scales on a high-altitude saline lake ecosystem. We analyze the evaporation trends over 70 years (1950–2020) at a high-spatial resolution. The method is based on the downscaling of 30 km ERA5 reanalysis data at hourly resolution to 0.1 km spatial resolution data, using artificial neural networks to analyze the main drivers of evaporation. To this end, we use the Penman open-water evaporation equation, modified to compensate for the energy balance non-closure and the ice cover formation on the lake during the night. Our estimation of the hourly climatology of evaporation shows a consistent agreement with eddy-covariance (EC) measurements and reveals that evaporation is controlled by different drivers depending on the time scale. At the sub-diurnal scale, mechanical turbulence is the primary driver of evaporation, and at this scale, it is not radiation-limited. At the seasonal scale, more than 70 % of the evaporation variability is explained by the radiative contribution term. At the same scale, and using a large-scale moisture tracking model, we identify the main sources of moisture to the Chilean Altiplano. In all cases, our regime of precipitation is controlled by large-scale weather patterns closely linked to climatological fluctuations. Moreover, seasonal evaporation significantly influences the saline lake surface spatial changes. From an interannual scale perspective, evaporation increased by 2.1 mm yr−1 during the entire study period, according to global temperature increases. Finally, we find that yearly evaporation depends on the El Niño–Southern Oscillation (ENSO), where warm and cool ENSO phases are associated with higher evaporation and precipitation rates, respectively. Our results show that warm ENSO phases increase evaporation rates by 15 %, whereas cold phases decrease it by 2 %.

Heat and moisture transfer in fabric consisting of fibers with low hygroscopicity

The heat and moisture transfer through dry and wet fabric made up of hydrophobic fibers was modeled and experimentally verified. In the modeling, the governing equations are obtained with consideration of the energy balance and the mass balance of the liquid water, where the specific initial and boundary conditions were set according to measurement of the cooling property of fabric. By comparing temperature changes at the fabric inner surface, the model validity was confirmed by the agreements between the experimental results and numerical solutions. Thus, this simulation was able to predict the cooling performance of fabrics. The effects of internal and external factors on heating/cooling performances of fabrics were analyzed by this model. With an increasing evaporation rate, thermal conductivity and water content of fabric, the cooling capability of fabric was improved. Surrounding conditions with lower temperature, lower relative humidity and higher air velocity demonstrated a positive effect on fabric thermal and moisture transfer performances, which benefits the thermal comfort of the human body after excessive sweating.

Evaporative water loss of 1.42 million global lakes

The evaporative loss from global lakes (natural and artificial) is a critical component of the terrestrial water and energy balance. However, the evaporation volume of these water bodies—from the spatial distribution to the long-term trend—is as of yet unknown. Here, using satellite observations and modeling tools, we quantified the evaporation volume from 1.42 million global lakes from 1985 to 2018. We find that the long-term average lake evaporation is 1500 ± 150 km3 year−1 and it has increased at a rate of 3.12 km3 year−1. The trend attributions include an increasing evaporation rate (58%), decreasing lake ice coverage (23%), and increasing lake surface area (19%). While only accounting for 5% of the global lake storage capacity, artificial lakes (i.e., reservoirs) contribute 16% to the evaporation volume. Our results underline the importance of using evaporation volume, rather than evaporation rate, as the primary index for assessing climatic impacts on lake systems.

Standard-Free Quantification of Dicarboxylic Acids: Case Studies with Salt-Rich Effluents and Serum.

The present study evaluates the ionization efficiency (IE) of linear and branched C2-C14 dicarboxylic acids (DCAs) by electrospray ionization (ESI) under different conditions. The influence of the concentration of organic modifier (MeOH); mobile phase additive; and its concentration, pH, and DCA structure on IE values is studied using flow injection analysis. The IE values of DCAs increase with the increase of MeOH concentration but also decrease with an increase of pH. The former is due to the increase in solvent evaporation rates; the latter is caused by an ion-pairing between the diacid and the cation (ammonium), which is confirmed by the study with different amines. The investigation of DCA ionization in the presence of different acidic mobile phase additives showed that a significant improvement in the (-)ESI responses of analytes was achieved in the presence of weak hydrophobic carboxylic acids, such as butyric or propanoic acid. Conversely, the use of strong carboxylic acids, such as trichloroacetic acid, was found to cause signal suppression. The results of the IE studies were used to develop the liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method that provided instrumental limits of detection in the range from 6 to 180 pg. Furthermore, upon applying the nonparametric Gaussian process, a model for the prediction of IE values was developed, which contains the number of carbons in the molecule and MeOH concentration as model parameters. As a case study, dicarboxylic acids are quantified in salt-rich effluent and blood serum samples using the developed LC-HRMS method.

Visualization research on influencing factors of flat heat pipes

Flat heat pipes can effectively spread a concentrated high power heat source in a small region into a larger heat dissipation area, which is widely used in the thermal management of electronic devices. In this paper, two different sintered copper powder wick structures are designed to study the effect of porous column height on the heat transfer performance. The results show that the best performance is achieved at the 30% filling ratio under the 15 ℃ cooling water with all the porous columns contacting with the condenser. The heat power is 312.7 W and the thermal resistance is 0.192 ℃/W. As the cooling water temperature increases, the evaporation rate increases, resulting in a decrease in the thermal resistance. But the decrease in temperature difference causes the decline in heat dissipation power. Through the visual observation, it is found that the porous column contacting with the condenser can not only play the role of support and liquid reflow pathway, but also serve as an effective evaporation area to improve the heat transfer performance. While the low porous column cannot transport the condensed liquid and is completely immersed by the liquid under the high filling ratio, which is difficult to promote evaporation rate. In order to improve the performance at air cooling situation, an integrated heat pipe combined the flat heat pipe and fin tubes is designed, which can achieve a heat power of 259.8 W and present excellent temperature uniformity. This research provides the guidelines to optimize the heat transfer performance of porous column wick structures.

Investigating the effects of carbon-based nanofluids on the interfacial evaporation of salt water under infrared light

Among the numerous alternatives to solving global water scarcity, carbon-based nanoparticles seem to be the likely preference for obtaining fresh water, due to their thermal conductivity, affordability, and effectiveness. In this study, carbon-based nanofluids were prepared using carbon black and graphene inclusions to determine the impact of nanoparticles on salt water evaporation rates and to evaluate the photothermal, heat transfer, and water evaporation kinetics. Different percentages (0.05. 0.5, and 0.1 wt%) of carbon black and graphene were added into a 3.5 wt% sodium chloride (NaCl) solution (simulated sea water), tap water, and deionized (DI) water. Test results revealed that 0.1 wt% of carbon-based nanoparticles homogenized with a base fluid provided higher water evaporation rates than either the 0.5% or 0.05% carbon-based nanoparticles under a simulated infrared light with a power of 125 W and intensity of 440 W/m2 for 2 h. For instance, using 0.1 wt% carbon black along with a black absorber increased evaporation rates by 18.77% for salt water, 17.98% for tap water, and 16.05% for DI water under the same conditions. Adding a black absorber at the base of the fluid further increased the evaporation rate and water temperatures by a considerable amount. Due to the existence of carbon-based nanoparticles, the base fluid’s temperature was increased, and the surface tension was decreased, which in turn increased the water evaporation rates significantly. In all the tests, the addition of carbon black nanoparticles showed slightly better evaporation results than the rest of the nanoparticles, which may be because of the changes in surface oxidation, agglomeration, density and surface area. This study may provide a new direction for fabricating more advanced systems using carbon-based nanoparticles for industrial applications such as solar desalination, wastewater treatment, solvent evaporation, environmental cleaning, and salt and mineral production.

Thermal performance analysis of a solar still with different absorber plates and external copper condenser

Solar distillation is one of the cheapest and lowest energy consuming desalination processes to produce potable drinking water. The main obstacle of desalination process is the low production rate of fresh water owing to slow evaporation and condensation rate of the system. In this experiment, a double slope solar still (SS) is modified by using two different modified absorber plates and an external copper condenser (ECC). Absorber plates are modified by employing triangular and rectangular channels as they increase surface area of the absorber plates to increase heat transfer to the basin water and hence increase evaporation rate of water. ECC is designed in such a way that provides extended cool surface area in addition with glass surface to increase condensation rate. Experiments are done in the month of October for 7 days and comparative analysis is done to determine the best modification out of the 5 modifications (conventional SS, SS with triangular channeled (TC) with and without ECC and SS with rectangular channeled (RC) with and without ECC) in terms of productivity and efficiency. The maximum average productivity obtained among all the modifications is 1.7 ± 0.1 L/m2 while experimenting with SS with TC absorber plates and ECC. The maximum average overall efficiency and maximum average instantaneous efficiency both are obtained with SS with TC and ECC which are 17.86 ± 0.6% and 18.2 ± 1.6% respectively. Addition of ECC increased the average productivity by 0.66 L/m2 and overall efficiency by 7.52% than conventional SS. The economic analysis of the SSs is also conducted, and results represent that the modified SSs are approximately 55.57% cost effective than the conventional SS.

Environmental Assessment of Future Potential Evaporation for Al-Najaf Governorate, Iraq through Evaluating Various Estimation Methods Using Statistical Downscaling Model

The hydrological cycle in nature is affected by climate changes, which are reflected in the water resources on the Earth (surface and underground) as evapotranspiration, thereby causing water scarcity. Increasing global temperature rates have exacerbated evaporation rates (PET). To estimate PET, scientists invented many mathematical equations, the most prominent of which is the Penman-Monteith equation. Most of the innovative methods require the provision of many parameters to be implemented; therefore, feasibly worthless for application in data mingy regions. The performance of the four PET estimation methods has been investigated depending either on temperature or radiation observed at Al-Najaf Governorate, Iraq. The accuracy and efficiency of each method have been evaluated with the outputs of the reference Penman-Monteith method. Through assessment, Hargreaves Samani temperature-based method reveals high acceptability of the estimated PET than the Jensen-Haise method and the other radiation-based methods (Penman and Makkink). The Statistical Downscaling Model/Tool (SDSM version 5.2) is applied to predict temperature values for the years 2050 and 2100. Estimated PET using Hargreaves Samani formula for 2050 and 2100 shows that Al-Najaf Governorate will encounter severe water scarcity due to the expected future increase in evaporation rates. Overall, regions classified as dry with high temperatures are compatible with methods of estimating PET values that depend on temperatures more than those that depend on radiation.

Effects Of Delayed Evaporation In Cellulose Acetate Membrane Preparation To Separate Co2/Ch4 At Low Pressure

The effect of delayed evaporation rate on CO2/CH4 selectivity was investigated on cellulose acetate based membrane in composition of cellulose acetate and acetone (CA+ACE), cellulose acetate, acetone and formamide (CA+ACE+F) and cellulose acetate, acetone, formamide and polyethylene glycol 400 (CA+ACE+F+PEG). Delayed evaporation was carried out in acetone saturated air. The study shows that the presence of PEG in membrane composition gives a probability for the membrane to be used and kept in dry state. Evaporation time at standard evaporation rate for membrane composition CA+ACE+F andd CA+ACE+F+PEG to get better selectivity is not less than 60 seconds. SEM shows that macrovoids in membrane prepared by delayed evaporation rate compared to those prepared by standard evaporation are smaller in size but higher in numbers.Effects of 60 seconds of delayed evaporation rate on membrane selectivity and permeability is about the same with the effects of 15 seconds of standard evaporation. It brought abourt, in turn, a thought, that the effects of 8 seconds evaporation in spineret on hollow fibre selectivity and permeability can be increased by increasing evaporation rate.

Future short-term estimation of flowrate of the Euphrates river catchment located in Al-Najaf Governorate, Iraq through using weather data and statistical downscaling model

Abstract The issue of global warming has negatively affected the global climate, which caused a decrease in the amount of precipitation and a significant increase in temperatures and evaporation rates. Iraq suffers from poor rainfall, which exacerbates the problem of declining water levels in rivers and the drying up of some tributaries. The Euphrates river, which passes through the eastern side of the Al-Najaf Governorate, is the case study in the current research. A statistical downscaling model is created for rainfall data from 2010 to 2020 with the aim of predicting the future precipitation biennially from 2022 to 2028. The model is calibrated and reflects close results with observations with high accuracy and reliability. The future precipitation levels are transformed after multiplying these levels by the total surface areas of the Euphrates river and its tributaries, and the value of future flowrates to be added to the Euphrates river is estimated. The results showed that the Euphrates river will receive a flowrate of 1,535,945 m3 in 2026, which is the highest value when compared with the values of flowrate for the years 2022, 2024, and 2028, which are estimated at 1,475,072, 1,456,037, and 1,378,403 m3, respectively.