Salt Deposition Rates Research Articles

Superhydrophilic Interconnected Biomass-Based Absorbers Toward High-Speed Evaporation for Solar Steam Generation.

Taking abundant and sustainable solar energy as the only energy source, solar-powered interface evaporation has been regarded as a promising method to alleviate the pressure of freshwater shortage. However, the uptake of clean water from brine is constantly accompanied by evaporation of water and condensation of vapor, which inevitably generates salt solid, preventing further continuous and stable evaporation. The most direct method is to fabricate a photothermal material with salt self-resistance by using the reflux of salt ions. Here, a superhydrophilic interconnected biomass carbon absorber (SBCA) is prepared by freeze-drying and carbonization, realizing strong liquid pumping, and self-blocking salt. In combination with superior broadband light absorption (94.91%), high porosity (95.9%), superhydrophilicity, and excellent thermal localization, an evaporation device with excellent evaporation rate (2.45kg m-2 h-1 under 1kW m-2) is successfully proposed. In the meantime, the porous skeleton and rapid water transport can enhance the diffusion of salt ions and slow down the rate of salt deposition. As a result, no salt deposition is found on the SBCA surface after continuous irradiation at 1kW m-2 for 15 h. The design can provide a convenient and low-cost efficient strategy for solar steam generators to address clean water acquisition.

Analytical expression for the skin factor of the salt deposition zone around a CO[formula omitted] injection well: Extension to the case of ternary miscible displacement

Anthropogenic CO2 disposal in saline aquifers is broadly acknowledged a feasible technique to mitigate climate changes. Scale deposition in the near-wellbore region can however reduce the performance of the CO2 injection wells utilized in the subsurface storage. In this study, we aim at evaluating the rate of salt precipitation and deposition and associated permeability reduction near a CO2 injection well completed in a saline aquifer. We employ a mathematical model of the CO2–H2O–NaCl fluid flow in a porous medium and take into account all relevant phase transitions. Then using a rather simple graphical construction with the fractional flow curve, we present a new analytical solution describing a radial flow of CO2 from the well. We demonstrate under certain assumptions that the solution contains two shocks traveling with a characteristic velocity and a rarefaction between them. The leading shock is the familiar Buckley–Leverett displacement front, whereas the trailing shock bounds the region of halite deposition in the near-wellbore region. We consider this region a skin zone and using the analytical solution, eventually derive a new simple relationship for the skin factor. We show that the skin factor caused by the halite deposition is most sensitive to the brine salinity and the relative permeability of the liquid phase. For particular reservoirs, a rather high value of the skin factor can be reached after injecting just several thousand tons of CO2. We show that the injection into reservoirs characterized by a high brine salinity and a large critical water saturation can cause the skin factor to be as high as four at an early stage of injection and as high as seven at a later stage. The proposed relationship can be useful for an instantaneous quantification of the skin and in reservoir simulations of the CO2 storage.

Mathematical modeling of the theory of salt and salt dust

This article describes that at the moment the level of the Aral Sea and the volume of water has decreased rapidly. The desiccation of the sea affected the entire region of its former water area as a whole: ports were closed, fishing in industrial volumes stopped, since the salinity of the water increased almost 10 times, and many species of flora and fauna could not survive in dramatically changed conditions. The climate of the Aral Sea has also changed – winter has become colder and longer, and summer has become even drier and hotter. Salinization of unsalted arable lands and further salinization of saline soils increases every year due to wind dust and salt from the Aral Sea and other saline soils. To maintain the fertility of irrigated saline soils, their salinization is washed annually (mainly in autumn and winter). To do this, the lands are inspected and washed away. During the washing process, part of the water is absorbed into the ground and carries away part of the salt. Most of the water leaves the cultivated fields and returns to drainage channels, from which to water supply channels for irrigation of crops, and then to rivers. The distribution of the rate and concentration of salt and sand deposition depends on the height and time above the level, it was determined that a number of positive works were carried out to improve the condition of the soil, its rational use and increase soil fertility, as well as to maintain the fertility of irrigated saline soils, their washing.

Surface evaluation of titanium oxynitride coatings used for developing layered cardiovascular stents

Stents are important medical devices used to increase the quality and life expectancy of patients with heart diseases and stroke, leading causes of death, worldwide. In order to minimize the risk of restenosis, different coating on bare metal stents (BMS) such as polymer coatings; titanium dioxide, titanium nitride or titanium oxynitride coatings; carbon coatings and others are used. The aim of this work was to develop novel stents coated with titanium oxynitride (TiOxNy) with optimal chemical, mechanical and biological properties having possibly good coverage rate of inner and outer stent surfaces. The improvement should be achieved by optimization and development of a magnetron sputtering deposition technology. The goal of the study is understanding of the existing potential for improvement of the deposition technology and the coating quality itself. For this study, different O2/N2 ratios, meaning 1/2, 1/5 and 1/10 (the ratios of reagent gasses are given for the values of mass flows into the chamber) has been selected. Stability in simulated body fluids, surface morphology and protein adsorption as well as preliminary cytotoxic behaviour of the samples on HUVEC cells has been analysed. SEM experiments have shown the potential in the improvement of coating-stent adhesion by all samples. TiOxNy 1:5 samples were found to have the lowest adsorption, the smoothest surface morphology and the smallest rate of salt deposition from simulated body fluids (SBFs). This kind of surface has been recommended for further optimization and application.

Flow, Transport, and Controlled Sedimentation of Salt Solutions in Porous Formations with Enhanced Structural Properties

Scaling phenomena caused by salt precipitation in pumps and wells are a frequent problem during oil production, CO2 storage, and other underground processes. Several studies have focused on the salt precipitation in porous media, and interesting results concerning salt precipitation have been obtained in the past. Salt precipitation in porous media is a complex phenomenon since it is highly dependent on supersaturation, which is usually not homogeneous along the porous channels. In the present study the coupled solution of the spatiotemporally varied flow and mass transport during mixing and selective precipitation of specific salts in unconsolidated and loosely consolidated porous media were investigated, with a strong dependence on the prevailing conditions. Specific salt solutions mixing, transfer, and deposition rates were studied, targeting the selective enhancement of salts deposition performance to facilitate consolidation of porous formations. Computational fluid dynamics methods have been applied...

The Influence of Salt Loading Density on the Atmospheric Corrosion of Aluminum

The relationship between NaCl on an aluminum surface and its corrosion rate in humid conditions is explored as a means of better understanding the impact of salt loading on atmospheric corrosion in service environments. Corrosion of aluminum and aluminum alloys under atmospheric exposure has been well documented for outdoor conditions.[1-8] These studies characterized effects of environmental severity and exposure factors that may control or enhance corrosion rates. One severity factor, salt deposition rate, results in higher corrosion rates with higher salt deposition rates.[7,14] The same correlative relationship has been reported in the fewer laboratory studies on this topic.[9-12] Figure 1 exemplifies these trends where mass loss of Al 4N, an Al-Mg alloy (AA 6061), and Al 1100 is correlated with salt deposition rate for field and lab accelerated exposures.[13] For all exposures and materials, corrosion rates increased with increasing deposition rates, except for AA 6061, which showed a stifling in corrosion rate in laboratory exposures above 100 mg/m2d. While these studies expose some environmental severity effects and indicate factors that may be controlling corrosion rates, they do not provide insight into the dependence of corrosion rate on salt deposition. Other laboratory studies have elucidated a phenomenon for atmospheric exposures of aluminum, in that corrosion rate diminishes with increased exposure time. Al samples exposed to humid air with 14 or 70 µg/cm2 coverage of NaCl displayed corrosion stifling at 200 h of exposure.[9,10] A thorough explanation to the stifling effect of corrosion over time under fixed NaCl loading conditions has not been fully developed. Possible theories have been put forth, including, the stability or passivation of the surface that shuts down the cathodic region, which is pH and, in turn, CO2 dependent [9,10] or the gettering of NaCl by corrosion product leading to surface drying and depletion of the corrosion aggressor. While there is data supporting the stifling of corrosion with increased ppm of CO2, empirical evidence of pH change is lacking, and there is no evidence to date of NaCl gettering. Also, the hypothesis that increased CO2 results in the stifling of corrosion suggests that corrosion would be independent of NaCl loading density. This presentation explores the effects of selected NaCl loading densities vs. exposure time of Al 1100 and Al 5N samples with isohumidity tests at a range of set RH. Pure Al samples were selected for study to establish a simplified corrosion system to understand atmospheric mechanisms which could then be expanded to common engineering alloys. Both macro and micro scale studies are undertaken to elucidate the possible mechanisms leading to corrosion stifling under fixed NaCl loading conditions. High throughput inkjet salt printing is applied to characterize corrosion rate via coupon-level studies. Gravimetry and optical profilometry are utilized to determine mass/volume loss of salt-loaded coupons exposed to humidity and provide indication of conditions leading to corrosion stifling. Micro scale explorations with in-situ time lapse imaging of micro-pipetted droplets exposed to isohumidity conditions can provide basic indication of electrolyte coverage and stability during exposure. Post-exposure analysis, including optical imaging, pH analysis, SEM, and vibrational spectroscopy will provide characterization of the evolution of electrolyte chemistry and corrosion product mineralogy. Through this work, an understanding of the relationship between corrosion in atmospheric systems versus the variation of a specific environmental severity factor, NaCl loading density, will be further developed.

Assessment of Distinctive Road Runoff Quality in Coastal Areas, Based on a Monitoring Case Study

High levels of marine salt deposition present in coastal areas have a relevant effect on road runoff characteristics. This study assesses this effect with the purpose of identifying the relationships between monitored water quality parameters and intrinsic site variables. To achieve this objective, an extensive monitoring program was conducted on a Portuguese coastal highway. The study included 30 rainfall events, in different weather, traffic, and salt deposition conditions. The evaluations of various water quality parameters were carried out in over 200 samples. In addition, the meteorological, hydrological, and traffic parameters were continuously measured. The salt deposition rates were determined by means of a wet candle device, which is an innovative feature of the monitoring program. The relation between road runoff pollutants and independent variables associated with weather, traffic, and salt deposition conditions was assessed. Significant correlations among pollutants were observed. A high salinity concentration and its influence on the road runoff were confirmed. Furthermore, the concentrations of the most relevant pollutants seemed to be very dependent on some meteorological variables, particularly the duration of the antecedent dry period prior to each rainfall event and the average wind speed.

Geochemical, isotopic, and mineralogical constraints on atmospheric deposition in the hyper-arid Atacama Desert, Chile

Modern atmospheric deposition across the Atacama was collected by an array of dust traps that stretched from the Pacific coast to the Andean altiplano, and the material was analyzed for its geochemical, mass and isotopic composition. The coastal trap had the second-highest insoluble mineral particle and highest soluble salt deposition rates due to significant inputs from the Morro Mejillones Range and the Pacific Ocean, respectively. The Andean trap had the highest insoluble mineral particle deposition owing to transport of weathered material, but the lowest deposition rate of soluble salts due to its distance from the ocean and anthropogenic sources. The removal of oceanic material was effective by the coastal mountains, while the westward transport of the Andean material was determined to be minimal. The atmospheric deposition in the inland traps was mainly from the local entrainment of surface material, inland anthropogenic emissions, and transport of marine aerosols. The nitrate isotopes (δ15N and Δ17O) suggested that NOx sources and NO3− chemistry shifted along the west–east transect, and were greatly impacted by anthropogenic emissions with soil NO3− being a minor source of deposited nitrogen.

Deposition of Corrosive Alkali Salt Vapors on the Blades of Gas Turbines Fueled by Coal-Derived Syngases

Many proposed clean coal technologies for power generation couple a gasification process with a gas turbine combined cycle unit. In the gasifier, the coal is converted into a syngas which is then cleaned and fired before entering the turbine. A problem is that coal-derived syngases may contain alkali metal impurities that combine with the sulfur and chlorine from the coal to form salts that deposit on the turbine blades, causing corrosion. This paper describes a new model, applicable to most types of coal, for predicting the dewpoint temperatures and deposition rates of these sodium and potassium salts. When chlorine is present the main alkali species in the mainstream gas flow are the chlorides; but when chlorine is absent, the superoxides dominate. However, because the high-pressure turbine blades are film-cooled, they are at much lower temperatures than the mainstream gas flow and analysis then shows that the deposit is composed almost entirely of the sulfates in either liquid or solid form. This is true whether or not chlorine is present. Detailed calculations using the new model to predict the alkali salt deposition rates on three stages of an example utility turbine are presented. The calculations show how the dewpoint temperatures and deposition rates vary with the gas-phase chlorine and sulfur levels as well as with the concentrations of sodium and potassium. It is shown that the locations where corrosion is to be expected vary considerably with the type of coal and the levels of impurities present.

Zebra stripes in the Atacama Desert: Fossil evidence of overland flow

Some hillslopes in the hyperarid region of the Atacama Desert in northern Chile have surface clasts organized into distinct, contour-parallel bands separated by bare soil. We call the bands “zebra stripes” due to the contrast between the darkly varnished clasts and the light-colored, salt-rich soil. Gravel that comprises the zebra stripes is sorted such that the coarsest clasts are at the downslope front and fine progressively upslope. How and when the zebra stripes formed are perplexing questions, particularly in a region experiencing prolonged hyperaridity. Using GoogleEarth, satellite imagery, and field observations, we report the first quantitative and qualitative observations of zebra stripes in order to test hypotheses of the mechanisms and timing of their formation. We consider soil shrink-swell, seismic shaking, and overland flow as possible formation mechanisms, and find that overland flow is the most likely. Based on cosmogenic 10Be concentrations in surface clasts, salt deposition rates from the atmosphere, and content in the soils, we propose that the salt-rich soils began accumulating ~106y ago and the zebra stripes formed 103–104y at the latest. The zebra stripe pattern has been preserved due to the self-stabilization of the clasts within the stripes and the continued absence of life (which would disturb the surface, as seen at a wetter site to the south). We conclude that the occurrence of zebra stripes is diagnostic of a set of distinct characteristics of local and/or regional precipitation, soil, hillslope form, and bedrock type.

Towards the development of a corrosion map for Abu Dhabi

AbstractInfrastructure development in the United Arab Emirates continues to escalate, yet very few corrosion studies have been performed in the region. In a step to address this situation, this paper reports on a study of zinc and steel corrosion and salt deposition rates at five sites in the Emirate of Abu Dhabi. The sites are classified as either urban/marine, marine, inland or mountainous. The study found that zinc corrosion rates range from 15 µm/year on the coast to 0.6 µm/year inland, while steel corrosion rates are 56 and 10 µm/year, respectively, at the same locations. While the salt deposition rate ranges from 5 to 18 mg/m2/day, it is not directly related to distance from the coast. Although the salt deposition rates observed are consistent with those at locations at similar latitudes, the corrosion rates are higher than in locations with comparable salt deposition rates. However, when the data were analysed along with relevant local meteorological data, it was found to be consistent with the basic assumptions of the holistic model of atmospheric corrosion developed by Cole et al. In particular, it is suggested that the relatively high corrosion rates observed here are associated with a greater accumulation of salt, which can occur in Abu Dhabi because rainfall, and thus rain washing, is extremely low compared to similar exposure locations in Australia and South‐East Asia.

A Natural Convection Model for the Rate of Salt Deposition From Near-Supercritical, Aqueous Solutions

Abstract A model is developed for the rate of salt deposition by natural convection from aqueous salt solutions onto a horizontal cylinder heated beyond the solubility temperature for the dissolved salt. The model accounts for the deposition rate at the salt layer-solution interface (SLSI) formed on the cylinder, but it does not account for deposition which may occur inside the porous salt layer (PSL). Dissolved salt is transported to the SLSI by molecular diffusion (with advection) and subsequently nucleates heterogeneously there. The model is applied to the experimental deposition rate data acquired by Hodes et al. (1998, 2002) at conditions pertinent to Supercritical Water Oxidation (SWCO). The ratio of the predicted deposition rate to the measured one ranges from roughly 0.5 to 2 indicating that deposition inside the PSL can be considerable.

On the Potential for Homogeneous Nucleation of Salt From Aqueous Solution in a Natural Convection Boundary Layer

Recent studies have examined the rate of salt deposition by natural convection on a cylinder heated above the solubility temperature corresponding to the concentration of salt in the surrounding solution at conditions typical of the Supercritical Water Oxidation (SCWO) process (Hodes et al. [1,2], Hodes [3]). The total deposition rate of salt on the cylinder is the sum of the rate of deposition at the salt layer-solution interface (SLSI) formed on the cylinder and that within the porous salt layer. The rate of deposition at the SLSI cannot be computed without determining whether or not salt nucleates homogeneously in the adjacent (natural convection) boundary layer. A methodology to determine whether or not homogeneous nucleation in the boundary layer is possible is presented here. Temperature and concentration profiles in the boundary layer are computed under the assumption that homogeneous nucleation does not occur. If, under this assumption, supersaturation does not occur, homogeneous nucleation is impossible. If supersaturation is present, homogeneous nucleation may or may not occur depending on the amount of metastability the solution can tolerate. It is shown that the Lewis number is the critical solution property in determining whether or not homogeneous nucleation is possible and a simple formula is developed to predict the Lewis number below which homogeneous nucleation is impossible for a given solubility boundary and set of operating conditions. Finally, the theory is shown to be consistent with experimental observations for which homogeneous nucleation is absent or present.

Deposition of sodium sulfate in a heated flow of supercritical water

AbstractWastes that can be treated by supercritical water oxidation often contain salts. Salts are almost insoluble under supercritical conditions and can result in severe fouling. A simple heat‐ and mass‐transfer model was developed and tested experimentally for sodium sulfate in a fully turbulent flow of water at 25 MPa. This model uses empirical heat‐transfer correlations to estimate mass‐transfer rates. The diffusion coefficient of the salt is calculated from the Stokes‐Einstein relation using a hydrodynamic diameter of 2 to 6 Å. New measurements of solubility showed that the solubility of sodium sulfate decreases by a factor of about 1,000 as the temperature increases from 380°C to 400°C. Salt deposition rates, inferred from the outside temperature of a heated test section, were reasonably close to the model predictions.

A preliminary investigation into airborne salinity adjacent to and within the envelope of Australian houses

Corrosion of metal components within the building envelope depends primarily on the levels of wetness and pollutants (in Australia the prime pollutant is sea salt) at the components' surface. This paper addresses the levels of airborne salinity within the envelope of a number of Australian buildings. Airborne salinity was measured using the salt candle technique. Salinity levels in the immediate vicinity of, adjacent to, and within the building envelope of six buildings were measured over periods up to one year. The factors affecting the rate of salt deposition are outlined. It is shown that the salt deposition is highly dependent on the distance from the coast. The effect of building structure in reducing airborne salinity levels is estimated. Estimates of corrosion rates in wall cavities resulting from the measured salinity levels are presented.

Theory of surface deposition from a binary dilute vapor-containing stream, allowing for equilibrium condensation within the laminar boundary layer

Deposition rates on solid targets cooled far below the dew point of undersaturated, dilute binary vapor and hot gas mainstreams have recently been found to be reduced and sharply surface temperature dependent compared to their pure vapor deposition counterparts. A rational yet tractable theory to account for such observations is formulated and exploited in particular cases of current practical interest; e.g. the deposition of trace multiple alkali sulfate vapors present in flowing combustion products. Our physicochemical model is based on the formation of a binary solution condensate aerosol near the deposition surface, with the resulting droplets collected by the mechanism of thermophoresis. The binary vapors, assumed here to be in local equilibrium with the solution aerosol phase, are collected by the familiar mechanism of Fick (concentration) diffusion across the prevailing laminar boundary layer (LBL) but we do not make the restrictive assumption that the Fick diffusivities are equal to the energy diffusivity of the carrier gas. As by-products of our calculation of the total (aerosol + vapor) deposition rate we obtain the BL position of condensation onset, as well as the structure of the LBL on either side of this binary “fog-locus”. Illustrative predictions are shown for the effects of Na 2SO 4(g) addition on salt deposition rates from combustion product streams containing a fixed amount of K 2SO 4(g), on the assumption that the resulting Na 2SO 4 + K 2SO 4 droplets form nearly ideal solutions, having droplet thermophoretic diffusivities within two decades of the host gas momentum diffusivity, v. With systematic corrections for the effects of (a) alkali salt vapor dissociation/equilibrium chemical reaction with the hydrocarbon combustion products and (b) slight solution non-ideality, the present theoretical formalism should be useful in accounting for binary nucleation onset effects observed in recent deposition rate experiments using alkali-seeded atmospheric pressure flat flames.

Response of Corn and Soybeans to Soil vs. Foliar‐Applied Salts of Cooling Tower Origin

AbstractField studies were conducted on corn (Zea mays L.) and soybeans [Glycine max (L.) Merr.] during 1976 and 1977 to acquire information on the response of crops to saline aerosol deposition near brackish water cooling towers in combination with salt accumulation in the soil.Salt treatments imposed included preplant soil applications equal to 0, 14, 28, 56, and 112 kg NaCl ha−1 and foliar applications of brackish cooling tower water as saline aerosol drift equal to 0, 34, and 68 L ha−1 d−1. Total soluble salt in the foliar treatments averaged 23 ± 3 g L−1, with average weekly salt deposition rates of 0, 3.8 ± 0.6, and 7.6 ± 1.2 kg ha−1. Information on elemental contents in leaves at flowering, leaf injury ratings, and grain yields were obtained. Information on extractable P, K, Ca, Mg, and Na plus electrical conductivity (EC) and pH of 0‐ to 15‐cm soil samples was obtained in October 1977 following two summers of treatments on the same plots and again in April 1978.For both crops, leaf Na and Cl, metabolic index, leaf injury ratings, and grain yields were significantly (P ≤ 0.05) affected by foliar salts in both years. However, soil salt treatments influence only leaf Cl contents and metabolic index values. Grain yields were reduced an average of 10 and 9% of controls at the highest foliar salt rate in corn and soybeans, respectively.Significant (P ≤ 0.05) increases in extractable Na in soils were found with foliar salt treatments. Increases in extractable Ca and pH (P ≤ 0.05) and K, Mg, and Na (P ≤ 0.1) were observed with increased soil salt rates. However, no differences were found among soil chemical parameters 8 months following the termination of the foliar treatments. The soils data suggest that salt deposition within 10 km of the Chalk Point cooling towers would cause minimal impact due to the sandy textures of the soils and annual rainfall in excess of 100 cm yr−1.

Response of Maryland Tobacco to Saline Aerosol Emissions From Brackish Water Cooling Towers

AbstractField studies were conducted on Maryland tobacco (Nicotiana tabacum L.) for 8 weeks during each summer from 1973 to 1977, to acquire information on the response of tobacco to simulated saline aerosol deposition from brackish water cooling towers. The studies involved two sources of salts (NaCl and brackish water from the Unit 3 cooling tower at Chalk Point, Md.), and various salt deposition rates (0.97 to 22.24 kg ha−1 week−1). Results obtained from these simulated drift studies were compared with results obtained from 12 monitoring sites located at 1.6‐, 4.8‐, and 9.6‐km distances from an operating natural‐draft cooling tower at Chalk Point, Md. over the period 1975 to 1978.No foliar injury symptoms associated with salt deposition were observed in either the simulation drift studies or cooling tower monitoring program during the investigation.In the simulated drift studies, regardless of salt sources or deposition rates, yield, average price, value, quality index, total alkaloid, and total N contents were found to be highly variable and generally non‐significant (p ≤0.05). However, trends for positive increases in yields were observed in four of the five studies at salt deposition rates ≤4.0 kg ha−1 week−1. No yield reductions were observed, even at salt deposition rates equal to 22.24 kg ha−1 week−1.Statistically significant (p ≤0.05) increases in leaf Na and Cl contents, and decreases in metabolic index [MI = (% P + % K + % Ca + % Mg)/(% Na + % Cl)] values and leaf burn duration were observed with increased salt deposition rates in all five studies.In the cooling tower monitoring program, no significant (p ≤0.05) differences were observed for yield, quality, burn, Cl contents or metabollic index value with respect to distances or years × distance interaction; however, year‐to‐year variation was significant. These resuits suggest that the operation of the Unit 3 cooling tower using brackish water was not having a significant impact on tobacco grown in the region.

Response of Corn and Soybeans to Simulated Saline Aerosol Drift from Brackish Water Cooling Towers

AbstractField studies were conducted on corn (Zea mays L.) and soybeans (Glycine max [L.] Merr.) for 8 weeks during each summer from 1973 to 1977 to acquire information on the response of these crops to saline aerosol deposition from brackish water cooling towers. The studies involved two sources of salts (NaCl and brackish water from the Unit No. 3 cooling tower at Chalk Point, Md.) and various salt deposition rates (0.97–22.24 kg ha−1 week−1).Soybeans exhibited greater sensitivity than corn to simulated saline aerosol drift early in their growth cycle, but corn yields were impacted more than soybean yields from the foliar salt treatments. Vegetative symptoms of salt injury on corn were progressively more pronounced as the plants matured than was the case with soybeans.Polynomial regression analyses of yields vs. salt deposition rates produced linear relationships for both crops. Corn yields were described by the relationship Yc = 97.9 − 1.94X and soybean yields by the relationship Ysb = 103.5 − 1.73X, where X equaled the rate of salt deposition, and yields (Y) were expressed as percent of nontreated controls.Changes in leaf Cl levels in corn in response to foliar‐applied salts were described by the relationship Y = 0.20 + 0.07X − 0.001X2, and leaf Na contents by the relationship Y = 0.099 + 0.024X. Changes in leaf Cl levels in soybeans in response to foliar‐applied salts were described by the relationship Y = 0.059 + 0.073X + 0.004X2 − 0.0004X3, and leaf Na levels by the relationship Y = 0.086 + 0.011X + 0.0006X2, where X equaled the salt deposition rate (kg ha−1 week−1) and Y equaled the element contents (%).In an effort to explore methods for assessing the levels of crop yield reductions in areas where salt deposition is suspected but no control plants are possible, corn yields were described by the relationship Yc = 105 − 35.5X1 and Yc = 102 − 63.7X2, where Yc equaled the percent of nontreated controls, and X1 and X2 equaled the Cl and Na contents (%), respectively. Soybean yields were described by the relationship Ysb = 104 − 20X1 and Ysb = 105 − 57.9X2, where X1 and X2 equaled the Cl and Na contents in leaves, respectively.

Determination of Salt Deposition Rates From Drift From Evaporative Cooling Towers

The purpose of this paper is to provide a method for estimating the deposition rate of the salt ejected in drift drops from a cooling tower in which salt water is circulated. The surface over which the salt will be distributed depends upon the wind speed, the maximum height the drops can reach, and the drop fall velocities. The drop fall velocity changes because of the evaporation in the air outside of the plume. The rate and extent of the evaporation is a function of the drop size, salt concentration, and ambient relative humidity. Three degrees of evaporation have been considered: (1) no evaporation; (2) evaporation to saturated solution and (3) evaporation to dry salt particles. For each degree of evaporation a graph was constructed that permits determination of the distance from the tower at which the salt contained in given drop size will fall. To use these graphs, the salt concentration, wind speed, and the maximum height a drop can reach must be known. The choice of the graph to be used for a particular case is made on the basis of humidity data for the site and the drift drop size. Corrections to compensate for the errors introduced by some of the assumptions are presented.