Search

A novel coupled mechanical and mass transport lattice discrete particle model is developed to quantitatively assess the impact of cracks on the mass transport properties in concrete members subjected to short‐ and long‐term loading conditions. In the developed approach, two sets of dual lattice networks are generated: one to resolve the mechanical response and another for mass transport analysis. The cracks simulated by the mechanical lattice are mapped onto the transport elements to investigate the effect of cracks on the global transport properties in concrete members. A new quantitative relationship is proposed for the estimation of the diffusion coefficient based on local crack information, and the developed model is capable of describing both convection and diffusion mechanisms. Moreover, creep behavior is incorporated to account for the influence of cracks induced by long‐term loading conditions. Numerical results, in the form of dynamic changes in cumulative water and chloride contents in concrete members under tension, compression, and bending with various stress levels show remarkable accuracy when compared to available experimental observations. The developed model provides an effective means for incorporating mesoscale information in simulations of water and chloride transport in concrete members under varying short‐ and long‐term loading conditions. [ABSTRACT FROM AUTHOR]

The effects of chlorides on the corrosion of steel bars within a matrix comprising modified magnesium oxysulfide (MMOS) cementitious materials was investigated. The phase composition, morphology and distribution of steel corrosion products (SCPs) were studied. There was basically no corrosion of the steel bars in the MMOS cement without chlorides. A high chloride content and a high water/cement (w/c) ratio in the MMOS matrix had adverse effects on the steel bar corrosion. The primary SCPs in the MMOS mixes were iron oxyhydroxides (FeOOH) and ferric oxide (Fe2O3), while ferrous oxide (FeO) was only observed at low w/c ratios, indicating a lower degree of oxidation. The presence of di-iron nonacarbonyl (Fe2(CO)9) at high w/c ratios suggested a higher degree of oxidation. At lower w/c ratios, rust products readily diffused. Conversely, at higher w/c ratios, these products accumulated close to the steel bars, resulting in a compact structure. [ABSTRACT FROM AUTHOR]

Woody plant encroachment is influenced by interactions between the physical environment and vegetation, which create heterogenous microenvironments some of which favor shrub recruitment through mitigation of the abiotic environment. Encroachment of native shrub, Morella cerifera into grasslands on Hog Island, Virginia has been attributed to warmer winter temperature; however, recruitment of seedlings in grasslands may be impacted by multiple factors at the level of the microhabitat. Our study focuses on a critical gap in understanding factors specifically influencing M. cerifera seedling recruitment and survival. By experimentally planting M. cerifera seedlings at varying dune elevations and grass densities, we tested hypotheses that dune elevation influences the microclimate, soil characteristics and vegetation cover and that grass cover/density is related to shrub establishment. We tested these hypotheses through gathering data from temperature data loggers, conducting soil water content and chloride analyses, and determining percent cover of grasses relative to dune elevation. Results indicate that dune elevation was positively related to moderated temperatures with reduced temperature extremes and vegetation cover/composition that led to favorable locations for M. cerifera establishment and growth. Where dune elevation is > 2 m, we document an upper limit of grass cover on natural seedling establishment, suggesting a switch from facilitative to competitive effects with grass density. Overall, our work demonstrates interactions between dune elevation and medium grass density has a facilitative influence on M. cerifera establishment and can be used for future predictions of shrub growth with rising sea-levels. [ABSTRACT FROM AUTHOR]

The research was aimed at studying pitting corrosion, which precedes the appearance of fistulas in steel and cast-iron pipelines in water supply systems and leads to significant expenditures. The process of fistula formation is accompanied by the formation of tubercles and craters on the surface of a corroding metal. The study focused on examining the qualitative and quantitative composition of the solution, which is generated inside the tubercles during their growth. It was found that, during the operation of water pipelines, the concentration of aggressive chloride ions inside the tubercles increases significantly compared to the chloride content of the source water. The increase in chloride concentration leads to an accelerated corrosion rate, potentially causing the formation of fistulas over time. As a result of the study, a mechanism for changing the mineral composition of the solution inside the tubercles has been proposed. This is due to the manifestation of selective properties by a dense layer of tubercles. The study also examined the appearance of crystalline forms of corrosion products that form after removing pipes from the water supply system. The study also reveals the conditions of corrosion products emerging. Further studies on the structure and properties of a dense layer of corrosive sediment could be used to evaluate the effectiveness of various corrosion inhibitors. [ABSTRACT FROM AUTHOR]

Concrete structure performance continuously deteriorates during operation, and the performance is simultaneously affected by chloride corrosion and repeated traffic loading. Repeated-loading-induced cracks have an impact on the rate of chloride corrosion. Chloride-induced concrete corrosion also affect the stress level of the structure under loading. Therefore, the coupled effect of repeated loading and chloride corrosion on the structural performance needs to be investigated. An upgraded test device was developed for chloride corrosion testing of unsaturated concrete structures under repeated loading. Based on the experimental results, considering the influence of repeated loading on the moisture diffusion coefficient and the chloride diffusion coefficient, a chloride transport model for unsaturated concrete under the coupled effect of repeated uniaxial compressive loading and corrosion was established. The chloride concentration under coupled loading was determined by the Crank–Nicolson finite difference method and the Thomas algorithm, and then chloride transport under the coupled effect of repeated loading and corrosion was analyzed. The results showed that the stress level and the repeated loading cycles directly affect the relative volumetric water content and chloride concentration in unsaturated concrete. The effect of chloride corrosion is more severe in unsaturated concrete compared to saturated concrete. [ABSTRACT FROM AUTHOR]

Objective: We investigated the horizontal migration and transformation of nitrogen in soil with oxalic acid and inhibitors (e.g., nitrification inhibitors, DMPP, urease inhibitors, and NBPT) under different soil water contents to provide a basis for the efficient utilization of nitrogen fertilizer in agricultural production in karst areas. Methods: Four nitrogen fertilizers (e.g., ammonium bicarbonate, ammonium sulfate, ammonium chloride, and urea) were applied separately and combined with oxalic acid, DMPP, and NBPT. The ammonium and nitrate nitrogen contents in the different soil layers were measured. The soil columns were cultured through an indoor soil column simulation at water content levels of 30%, 40%, and flooded (50%) for 30 days. Results: Ammonium bicarbonate with inhibitors increased soil NH4 +-N content by 15.42-21.12%. Ammonium sulfate with oxalic acid or NBPT increased soil NH4 +-N content by 27.56-52.25% at 30% and 40% moisture content treatments, compared to ammonium sulfate alone. Urea with DMPP application significantly increased soil NH4 +-N content by 11.93-14.87% at 40% water content and flooded conditions. In all treatments, the NH4 +-N content in the soil treated with 30% water content of ammonium chloride with oxalic acid was the highest. The NH4 +-N content showed a decreasing trend with an increase in the water content. The NO3 --N content in soil treated with ammonium bicarbonate and DMPP was higher than that treated with other nitrogen fertilizers at 30% moisture. The NO3 --N content decreased with increased water content. Under all treatments, ammonium chloride with oxalic acid had the highest percentage of soil NH4 +-N and soil soluble inorganic nitrogen at 30% water content, with 55.29% and 55.97%, respectively. Conclusion: Among the nitrogen fertilizer treatments, the soil NH4 +-N content increased in ammonium bicarbonate with DMPP or NBPT, ammonium sulfate with oxalic acid or NBPT, and urea with DMPP. The four nitrogen fertilizers with DMPP increased the soil NO3 --N content. Nitrogen fertilizer combined with oxalic acid and inhibitors could effectively improve the effective use of nitrogen fertilizer. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Lake Chad basin, located in the centre of northern Africa, is characterized by strong climate seasonality with a pronounced short annual precipitation period and high potential evapotranspiration. Groundwater is an essential source for drinking-water supply, as well as for agriculture and groundwater-related ecosystems. Thus, assessment of groundwater recharge is very important although also difficult because of the strong effects of evaporation and transpiration, as well as the limited available data. A simple, generalized approach, which requires only limited field data, freely available remote sensing data, and well-established concepts and models, is tested for assessing groundwater recharge in the southern part of the basin. This work uses the FAO dual- Kc concept to estimate E and T coefficients at six locations that differ in soil texture, climate, and vegetation conditions. Measured values of soil water content and chloride concentrations along vertical soil profiles together with different scenarios for E and T partitioning and a Bayesian calibration approach are used to numerically simulate water flow and chloride transport using Hydrus-1D. Average groundwater recharge rates and the associated model uncertainty at the six locations are assessed for the 2003–2016 time period. Annual groundwater recharge varies between 6 and 93 mm and depends strongly on soil texture and related water retention and on vegetation. Interannual variability of groundwater recharge is generally greater than the uncertainty of the simulated groundwater recharge. [ABSTRACT FROM AUTHOR]

Despite human activities have currently increased the global flux of fluoride into the atmosphere and in rivers by more than a factor of 2 (Schlesinger et al., 2020), national water quality criteria for fluoride to protect freshwater biota have been established in only a few countries. Lastly, because the mean level of fluoride in freshwater across Canada is 0.05 mg F SP - sp /L (Environment Canada, 2001), Parker et al.'s (2022) water quality benchmarks (3.4-10.4 mg F SP - sp /L) would allow fluoride pollution levels 70-200 times higher than natural fluoride levels. [Extracted from the article]

An ion chromatography (IC) system with switching recycling column was developed for the determination of bromate in drinking water with high chloride content. The system included a pump, two switching valves, guard column and analytical column, suppressor and a conductivity detector. In this method, the single eluent was used for both online collection and matrix elimination, and bromate was eluted from the concentrator column to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r  = 0.9995) in the range of 1–100 μg/L and repeatability (RSD ≤ 4.80%, n  = 6). The limit of detection was 0.2 μg/L (S/N = 3) with 1000 μL sample volume injections. The method was applied to analysis of drinking and tap waters, and satisfactory recoveries of spiked samples between 96.8% and 108.7% were obtained. The result showed that the recycling column-switching system can be useful for the determination of traces of bromate in high-chloride samples, which is required in production of the drinking water and quality control of the final product. [ABSTRACT FROM AUTHOR]

The search of new solvents is currently focused on deep eutectic solvents (DES). However, there are not many ecotoxicological studies in different biomodels of DES that allow knowing how these chemicals affect to the environment along the trophic chain. In this manuscript, two DES at different proportion of water have been prepared and characterized from the ecotoxicological point of view. These solvents are glucose:choline chloride (2:5) and sorbitol:choline chloride (3:2) at different contents of water. To carry out the ecotoxicological study, three biomodels have been used: bacteria Aliivibrio fisheri (A. fisheri), crustacean Daphnia magna (D. magna) and algae Raphidocelis subcapitata (R. subcapitata). The obtained results show that the ecotoxicity of these chemicals depends on the biomodel used and the amount of water, being toxicity values lower for chemicals with higher water content. However, it is important to highlight that the ecotoxicity for all chemicals is quite low with effective concentrations, EC50 values above 1000 mg/L in all the studied cases. [ABSTRACT FROM AUTHOR]

Nitrate and Residual Chloride have a great effect on human health when taken with drinking water in high concentrations. Therefore, this study is an attempt to evaluate the concentration of Nitrate and Residual Chloride in drinking water. Water samples were collected from household tanks in Al-Diwaniyah city-Iraq for six months (from January to June 2019). The study included most of Al-Diwaniyah neighborhoods, they numbered 15, and they are Al-Orouba First, Al-Orouba Second, Al-Orouba Third, Al-Dhubat, Al-Askari (Al-Sadr Fourth), Al-Jazzier, Umm Al-Khail, Al-Furat, Al-Judida, Al-Jamaa, Al-Nahda, Al-Iskan, Al-Taqiya, Sob Al-Shamiya, and Al-Jumhouri. The results of this study confirmed the variation in nitrate and residual chloride concentrations with different study months and sample locations. The lowest nitrate concentration was 3.19 mg/l in February in the Al-Jamaa neighborhood. The highest concentration was 5.15 mg/l in January in the Al-Taqiya neighborhood. The residual chloride reached its highest concentration of 4 mg/l in January in the Al-Jazzier neighborhood and the lowest concentration was 0 mg/l in May and June in the Al-Taqiya neighborhood and June in the Umm Al-Khail neighborhood. The results also showed that the nitrates did not exceed the Iraqi standard specification and international standards. While chlorine exceeded the specifications as there was no residual chloride in some samples or it did not reach the minimum required concentration. [ABSTRACT FROM AUTHOR]

The electrical resistivity of concrete is an important property in the assessment of reinforcement corrosion in concrete and an essential parameter in the design and operation of cathodic protection for reinforced-concrete (RC) structures. Water and chloride contents in concrete are highly variable in RC structures in real-world hostile environments, meaning that characterisation of their coupled effects on concrete electrical resistivity is important. The currently available models are investigated in this paper. As all the current models are purely empirical, an improvement with a semi-empirical model is proposed. The improvement highlights the intrinsic linkage between concrete electrical resistivity and water content and the pore size distribution of concrete. The proposed model was tested using two sets of experimental data and was also compared with other two empirical models. [ABSTRACT FROM AUTHOR]

In this work, novel calibration curves and calibration surfaces of Electromagnetic (EM) characteristics are modeled as a function of the water and chloride contents of concrete. An experimental campaign was carried out on cores extracted from two types of concretes: C1 (Ordinary Portland Concrete) and C3 (62% slag + 38% clinker). The cores were initially saturated at three sodium chloride (NaCl) concentrations and then oven-dried to attain different degrees of saturation. They were tested with the electromagnetic and electrical cell to determine the dielectric permittivity and electrical resistivity, respectively, at the targeted hydric and chloride ion contents. The calibration curves and calibration surfaces, which represent the resistivity and permittivity as a function of chloride content and/or degree of saturation, were adjusted and presented for both concretes. The calibration surfaces developed herein serve as an essential tool to study complex phenomena, such as the coupled water-chloride ingress. • Developing novel calibration curves and calibration surfaces that correlate the permittivity and resistivity of concrete to its chloride and water content. • Investigating the impact of slag on the permittivity and resistivity of concrete. • Proposing a non-destructive methodology to monitor chloride and water content for reinforced concrete structures exposed to a tidal zone. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A highly contributing factor to impairment of water quality is stormwater that flows across the urban landscape, picking up pollutants along the way, which is directed by a system of stormwater infrastructure to be deposited in the nearest water body. Though state regulations to manage stormwater are in place, there is a need to strengthen and expand them to address chloride impairment. Chloride impairment stems from the use of road salt during the winter season, and is a serious concern for current and future urban streams. The only cost-effective method to address this impairment is by reducing the amount that is used. Such a reduction must come from public and private property owners alike. This can be achieved through permitting via the National Pollutant Discharge Elimination System, which Maine is authorized to implement, or through the state-wide stormwater regulations that apply when property is developed. Not doing so means the quality of Maine's water will continue to further degrade, an unacceptable option in the face of the Clean Water Act and the health of the public and our environment. [ABSTRACT FROM AUTHOR]

In this study, we simulated and predicted the accumulation of deicing agents in the soil and water system of the study area (a ski resort in Beijing, China) and discussed the environmental impact of deicing agents on the surrounding water system and soil under a standardized dosage. The widely used sodium chloride deicing agent was selected, and the standardized dosage of the deicing agent was estimated. Analysing the prediction results of the changes in chloride ion content in water systems and soils after the use of deicing agents from 2021 to 2029 leads to the conclusion that the use of deicing agents will increase the chloride ion content of the study area. It is predicted that chloride ion content in the water system and soil will increase year-by-year from 2021 to 2026, achieving a stable trend after 2027. It is concluded that the deicing agent has no obvious effect on the surrounding water body and soil under the standardized dosage. This research is intended to fill the gap in quantitative research on the environmental impact of deicing agents, to provide a reference and guidance for the engineering application of deicing agents, and to offer support for the improvement of deicing agent management measures. [ABSTRACT FROM AUTHOR]

The adsorption, protective, and passivating effects of sodium salts of malonic and ethylmalonic acids on the oxidized and reduced surface of copper and MNZh 5-1 copper alloy in a neutral chloride solution have been studied. It was shown that sodium ethyl malonate anions, which are less hydrophilic than sodium malonate, have higher adsorption free energies () on copper and MNZh 5-1 alloy at E = 0.0 V. On copper, they are 69.4 and 47.7 kJ/mol, respectively, and they are 78.7 and 74.1 kJ/mol on the MNZh 5-1 alloy. Such values () indicate the chemisorption of anions of both inhibitors on the surface, and their stronger adsorption on the alloy, apparently, is due to its increased adsorption activity of the heterogeneous surface as compared to copper. The thicknesses of conditional monolayers of inhibitors on metal and alloy surfaces have been calculated. At cathode potential E = –0.60 V on the reduced copper surface, the values () are significantly less (for malonate and ethyl malonate, respectively, they are 38.3 and 64.2 kJ/mol). Corrosion testing of copper in water with a chloride content of 10 mmol/L also showed the advantage of ethyl malonate over malonate. At the same time, for Cin = 1.5 mmol/L, the degree of protection is 71 and 65%, respectively. Practically complete suppression of copper corrosion (degree of protection 91%) with sodium ethylmalonate is achieved at Cin = 3 mmol/L. [ABSTRACT FROM AUTHOR]

The chloride mass balance method of estimating groundwater recharge is generally applied at a point scale but water resources management generally requires information at a regional scale. To estimate groundwater recharge regionally previously used upscaling methods have ranged from simple averaging to empirical relationships and geostatistical interpolation. This study combined the best components of these methods by using regression kriging: in data-sparse areas the recharge is upscaled using global regression equations with gridded rainfall and surface geology as covariates, while in data-dense areas the kriging of the regression equation residuals ensures that the upscaled recharge estimates respect the point estimates of recharge. The uncertainty in the recharge estimates was quantified using 1000 stochastic replicates of the chloride deposition of rainfall, the chloride exported in runoff, the chloride concentration of the groundwater and the regression equations used to perform the upscaling. This study focused on the coal bearing Sydney, Gunnedah, Gloucester and Surat Basins of Eastern New South Wales (Australia). Historically, groundwater recharge to the Permian units of these basins has received little attention due to their low yields of poor quality water. The increased potential extraction of regional groundwater due to coal development has demanded a greater understanding of the water balance. We found that recharge is highest in the younger productive aquifers (up to 20% of long-term mean annual rainfall) and lowest in the Permian units (∼1% of long-term mean annual rainfall). The magnitude of the uncertainty is often close to the magnitude of the median recharge estimate. The method developed here for upscaling the point estimates of recharge using the chloride mass balance provides robust estimates of recharge and its associated uncertainty. The method is applicable to any regional study with variable density input data. [ABSTRACT FROM AUTHOR]

Chlorine is geochemically stable and is widely used as a groundwater tracer. Stable isotopes of chlorine ( 35 Cl and 37 Cl) are fractionated by diffusion and are used to characterize diffusion-dominant systems, understand seawater intrusion and identify the origin of chlorine. However, a method for measuring the fractionation factor by diffusion (α = D Cl−35  / D Cl−37 ) has not been established for rock samples. We propose a method for measuring α using a conventional through-diffusion experiment, in which a sample is embanked by a high- to low-concentration tank. This study shows that theoretically, the diffusive flux in a through-diffusion experiment should have mass ratio fractionated by diffusion and that the difference between δ 37 Cl in the high- to low-concentration tank will approach to 10 3 ln α with time. The results of the through-diffusion experiment showed a significant difference between δ 37 Cl in the high- and low-concentration tanks. Measured α ranged from 1.0015–1.0022, which is in good agreement with previous studies. Moreover, the sampling period and correction method are suggested to determine α excluding errors due to an unsteady state. The proposed method is applicable to other isotopes to measure α and will contribute to a more quantitative evaluation of Cl and δ 37 Cl profiles. [ABSTRACT FROM AUTHOR]

Accurate modelling of chlorine concentrations throughout a drinking water system needs sound mathematical descriptions of decay mechanisms in bulk water and at pipe walls. Wall-reaction rates along pipelines in three different systems were calculated from differences between field chlorine profiles and accurately modelled bulk decay. Lined pipes with sufficiently large diameters (>500 mm) and higher chlorine concentrations (>0.5 mg/L) had negligible wall-decay rates, compared with bulk-decay rates. Further downstream, wall-reaction rate consistently increased (peaking around 0.15 mg/dm 2 /h) as chlorine concentration decreased, until mass-transport to the wall was controlling wall reaction. These results contradict wall-reaction models, including those incorporated in the EPANET software, which assume wall decay is of either zero-order (constant decay rate) or first-order (wall-decay rate reduces with chlorine concentration). Instead, results are consistent with facilitation of the wall reaction by biofilm activity, rather than surficial chemical reactions. A new model of wall reaction combines the effect of biofilm activity moderated by chlorine concentration and mass-transport limitation. This wall reaction model, with an accurate bulk chlorine decay model, is essential for sufficiently accurate prediction of chlorine residuals towards the end of distribution systems and therefore control of microbial contamination. Implementing this model in EPANET-MSX (or similar) software enables the accurate chlorine modelling required for improving disinfection strategies in drinking water networks. New insight into the effect of chlorine on biofilm can also assist in controlling biofilm to maintain chlorine residuals. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop and evaluate the characteristics and performance of a portable electrolytic sanitising unit. Free available chlorine (FAC), oxidation-reduction potential, and pH of electrolysed water were measured. Response surface methodology coupled with a Box-Behnken design was used to describe the input-output relationship and optimise FAC production. A partial catholyte solution was reintroduced to electrolysis for generating neutral electrolysed water. The result found that RuO 2 -IrO 2 /TiO 2 electrode was very effective. A FAC concentration of 4 mg/L achieved >2 log CFU/mL reduction, while a FAC concentration of 40 mg/L achieved >6 log CFU/mL reduction in Escherichia coli O157:H7 and Listeria monocytogenes BAA-839. The developed sanitiser had a pH of 7.08 ± 0.08, and the commercial sanitiser had a pH of 3.77 ± 0.18. The developed sanitiser had similar bactericidal effects as the commercial sanitiser. The results revealed that the developed sanitising unit is promising for the control of foodborne pathogens. [ABSTRACT FROM AUTHOR]

Dissolved chloride is a commonly used geochemical tracer in hydrological studies. Assumptions underlying many chloride-based tracer methods do not hold where processes such as halide-bearing mineral dissolution, fluid mixing, or diffusion modify dissolved Cl − concentrations. Failure to identify, quantify, or correct such processes can introduce significant uncertainty to chloride-based tracer calculations. Mass balance or isotopic techniques offer a means to address this uncertainty, however, concurrent evaporation or transpiration can complicate corrections. In this study Cl/Br ratios are used to derive equations that can be used to correct a solution’s total dissolved Cl − and Br − concentration for inputs from mineral dissolution and/or binary mixing. We demonstrate the equations’ applicability to waters modified by evapotranspiration. The equations can be used to quickly determine the maximum proportion of dissolved Cl − and Br − from each end-member, providing no halide-bearing minerals have precipitated and the Cl/Br ratio of each end member is known. This allows rapid evaluation of halite dissolution or binary mixing contributions to total dissolved Cl − and Br − . Equation sensitivity to heterogeneity and analytical uncertainty is demonstrated through bench-top experiments simulating halite dissolution and variable degrees of evapotranspiration, as commonly occur in arid environments. The predictions agree with the experimental results to within 6% and typically much less, with the sensitivity of the predicted results varying as a function of end-member compositions and analytical uncertainty. Finally, we present a case-study illustrating how the equations presented here can be used to quantify Cl − and Br − sources and sinks in surface water and groundwater and how the equations can be applied to constrain uncertainty in chloride-based tracer calculations. [ABSTRACT FROM AUTHOR]

The combination of ultrasound (US) with chlorinated water (CW) and neutral detergent (ND) for simultaneous cleaning and sanitation of knives used during cattle slaughter was evaluated as a novel non thermal treatment. The US mode of operation, detergent concentration and time of treatment were studied and the results were compared with the conventional sanitation method used in meat industries. The conventional sanitation method promoted a decrease (p < 0.05) in the counts of mesophiles, Enterobacteriaceae , molds and yeasts, and a similar behavior was observed for US + CW (2.05 ± 0.08 mg/l of chlorine, and mode operation normal and sweep for 10 min) and US + CW + ND (5 ml/l and mode operation sweep for 5 min) methods. Nevertheless, when detergent concentration and sonication time were increased (20 ml/l, 15 min) a strong decrease (p < 0.05) in the counts of mesophiles, Enterobacteriaceae , Staphylococcus aureus , molds and yeasts. Knife blades presented appropriate hygienic-sanitary properties in such conditions based on the Clean-Trace Surface Protein Plus ™ test swab, which were better than the results obtained from conventional method. Kinetic modeling of knife sanitation was performed according to the transfer of organic matter, nitrogen and phosphorus during the process indicated highest migration rate of residues for US + CW + ND method, reaching 1.61 mg/l·min. The hardness of knives' surface (Rockwell) was not changed by sonication using US + CW + ND method. These results indicate that both knife cleaning and sanitation processes could be performed in a unique step without the use of heat. [ABSTRACT FROM AUTHOR]

• Description of the sensing principles of chloride ingress monitoring by a radiofrequency dielectric probe. • Decoupling the influence of water and chloride ingress is possible with the proposed method. • Ability of the method to monitor diffusion of chloride in concrete at different depths. The origin of rebars corrosion in concrete infrastructures is frequently associated with the ingress of chloride ions present in water. This is particularly the case of infrastructures located in marine environments or exposed to deicing salts. The present study aims at developing a radio-frequency dielectric sensor dedicated to free chloride ingress monitoring in a well-defined volume of the material. A resonant method operating in a wide frequency range is selected to separate the effects associated with the variation of the real part of the dielectric permittivity and tangent loss. As it will be shown, the method provides useful information on the presence of free chloride in concrete and can be used for the monitoring of chloride diffusion. For this purpose, considering the variation of the transmission parameter S12 value presents clearly some advantages with respect to the frequency shifts of resonances. This allows to decouple water and chloride content. [ABSTRACT FROM AUTHOR]

Waste liquid treatment is widely concerned with the deepening of people's awareness of environmental protection, especially for the waste liquid with a high chemical oxygen demand (COD), which also has a high calorific value and makes it possible for the incineration treatment. In this study, the pyrolysis and combustion characteristics of pesticide waste liquid (PWL) are investigated by using thermogravimetric experiment and kinetic analysis, and the effects of different water and salt contents on its pyrolysis and combustion are discussed. The results show that both pyrolysis and combustion processes of the simulated pesticide waste liquid (sPWL) could be divided into two stages. As the water content increases from 0% to 18.5%, the volatilization characteristic index of stage Ⅰ (low temperature) increases by 263.31%, while that of stage Ⅱ (high temperature) decreases by 28.32%, and the water content could promote the pyrolysis and comprehensive combustion performance of the sPWL. As the sodium chloride contents increase from 0% to 1.5%, both the pyrolysis and combustion process of the PWL are enhanced, and the volatile release characteristic index, the ignition temperature and burnout characteristic index increase by 60.77%, 18.74% and 47.95%, respectively. By the means of the Coats-Redfern integral method, the kinetics of the pyrolysis and combustion of the PWL are analyzed, with a linear correlation coefficient of more than 95%. In a whole, a suitable water and sodium chloride content in the pretreatment process is crucial for efficient and low-cost treatment of waste liquid, which can promote the pyrolysis and combustion processes. These results are expected to provide several insightful guidance for the efficient treatment of the waste liquid. • The pyrolysis and combustion characteristics of pesticide waste liquid are studied. • The effects of the water and salt contents in pesticide waste liquid are analyzed. • The pyrolysis and combustion process of waste liquid is divided into two stages. • Water can promote pyrolysis and improve the combustion of the waste liquid. • The sodium chloride in waste liquid should be controlled in the pretreatment stage. [ABSTRACT FROM AUTHOR]

Chloride can accumulate in chlorinated swimming pool water. Although substantial efforts have been made to examine the effects of halide ions on the formation of volatile disinfection byproducts (DBPs), most have focused on bromide. The effects of chloride ion concentration on the formation of volatile DBPs in swimming pools remain largely unstudied. In this study, chlorination of typical precursors and body fluid analogue (BFA) were investigated with variable chloride concentration and pH. The formation of three volatile DBPs (NCl 3 , CHCl 3 and CNCHCl 2 ) was observed to be linearly correlated with chloride concentration, both in bench experiments and in actual swimming pool water samples. Free chlorine consumption was also observed to increase with chloride concentration. These behaviors appear to be attributable to shifts in speciation of free chlorine, with higher chloride resulting in higher concentration of molecular chlorine (Cl 2 ), which is much more reactive than HOCl. The results of this work suggest that changes in pool management strategies to promote low chloride concentration could be important for control of volatile DBPs in pools and to economize free chlorine usage. [ABSTRACT FROM AUTHOR]

Experiments were run in the pipe loop setup to estimate bulk and wall chlorine decay rates under varying flow and chlorine levels for groundwater. A recirculating loop of 50 mm inner diameter polyvinyl chloride pipe and a variable flow pump with feed and recirculation tank were used to design a pipe loop. Sodium hypochlorite was introduced as free chlorine into the test water. The study came up with three important findings: (a) bulk chlorine decay rate in test water decreased with increase in chlorine levels, which is attributed to the type and level of organic matter present in test water. (b) Chlorine decay rate in pilot loop setup increased with increase in flow velocity. The result showed that under turbulent conditions, in addition to chlorine, mass flux transfer from bulk to wall and biofilm removal from pipe surface contributed to chlorine decay. We also noted that with increase in flow velocity the contribution of bulk reaction to total chlorine decay in pipe loop decreased. (c) ANOVA test on experimental dataset showed that as compared to initial chlorine levels, flow velocity has statistically significant effect on chlorine dissipation in a pipe loop. We also found that after turbulent flow is achieved, the effect of flow velocity on the wall decay is negligible. [ABSTRACT FROM AUTHOR]

Cold work of materials, dissolved oxygen and chloride in water are crucial factors that accelerate the stress corrosion cracking (SCC) crack growth rate of stainless steel in high temperature water. Cold worked austenitic stainless steel type 316 and 316L were studied in order to obtain their effects on SCC crack growth rates in 288 and 325 °C water. Similar SCC behavior were identified for 316 and 316L. Cold working induced comparatively high crack growth rate up to 10 −8 mm/s even in hydrogenated water, and the collaboration of dissolved oxygen and chloride in water accelerated the SCC crack growth rates much more significantly. [ABSTRACT FROM AUTHOR]

In this study, a new sensitised spectrofluorometric method was presented as a probe sensor for hypochlorite analysis in oral and tap water samples. By capping L-tyrosine (Tyr) on ZnSe nanoparticles, stable quantum dots (QDs) were obtained. In comparison with Tyr, the fluorescence (FL) emission of Tyr-capped ZnSe is enhanced and shifted to greater wavelength, which causes to enhance the sensitivity for the determination of hypochlorite. Based on the FL quenching of the Tyr-capped ZnSe QDs, hypochlorite concentration was detected at buffering pH of 7 in the range of 5.15 × 10−5‒2.57 × 10−2g L−1. Relative standard deviation and detection limit were found to be 0.83% and 2.06 × 10−5g L−1, respectively. In comparison with the other methods of hypochlorite determination, this method is simple, fast and inexpensive, with low sample volume consumption. It also exhibits a good selectivity. [ABSTRACT FROM AUTHOR]

In order to effectively separate chloride (such as NaCl) and sulfate (such as Na 2 SO 4 ) for high saline wastewater recycling, one commercial NF membrane (named Desal-DL) was employed in the permeation of the single and binary salt solutions of NaCl and Na 2 SO 4 with a lab-scale cross-flow batch module, where the salt concentration ranged from 4 to 96 g L −1 and the operating pressures varied from 0.6 to 2.4 MPa as well as the temperature was kept under room temperature. The experimental results showed that the Desal-DL NF membrane had a low rejection to NaCl and a high rejection to Na 2 SO 4 for single salt solutions. While for binary salt solutions, the membrane presented a bit higher rejection to SO 4 2− and much lower rejection to Cl − , even special negative rejection to Cl − was observed when the concentration of Na 2 SO 4 was high. This implies that NF is suitable to be used for the separation of Na 2 SO 4 and NaCl from their binary solution, where Na 2 SO 4 could be retained by the NF membrane and concentrated to high concentration while NaCl could pass through the membrane and might be diluted to low concentration with a diafiltration operation mode. Finally the selective separation of Na 2 SO 4 and NaCl by NF diafiltration was simulated for the binary salt solution containing 23.4 g L −1 NaCl and 8.76 g L −1 Na 2 SO 4 . A highly concentrated solution of Na 2 SO 4 (71.74 g L −1 ) and a relatively pure solution of NaCl (20.79 g L −1 ) were obtained, which favored the post-treatment of high saline wastewater for inorganic salts recycling. [ABSTRACT FROM AUTHOR]

Adsorbable organic halogens (AOX) were measured at the outlet (AOXo) and after 24 h contact time with residual disinfectant (AOX24 h) for 10 samples obtained from 7 drinking water treatment plants (WTPs) that employ chlorine-based disinfectants. AOXo ranged from 0.75 to 7.60 µM (26.2-266.0 µgCl=L) and increased by up to 170% after 24 h contact time. The results were also compared with AOX formation potential (AOXFP) measured in the laboratory for the samples collected prior to disinfection at the same WTPs. In general, AOX24 h and AOXFP values varied by less than ±20%. A suite of disinfection byproducts (DBPs) were individually measured to elucidate the AOX composition. Trihalomethanes and haloacetic acids explained the largest fraction of AOX; however, the percentage of AOX not accounted for by measured DBPs varied greatly between samples (14.5-62.0%). Additionally, the fate of AOXFP was assessed across the seven WTPs. On average, coagulation removed 67 ± 7% of AOXFP across the WTPs, while dual media filtration did not substantially remove AOXFP. The effect of ozone on AOXFP varied between WTPs, while biological activated carbon filtration removed 33 ± 13% AOXFP. The ratio of known versus unknown AOXFP did not change across the WTPs. [ABSTRACT FROM AUTHOR]

This study investigated the degradation of clofibric acid and formation of perchlorate during the electro-peroxone (E-peroxone) treatment of chloride-containing (26.1–100 mg L −1 ) water (Na 2 SO 4 electrolytes and secondary effluents). The E-peroxone process involves sparging O 2 and O 3 gas mixture into an electrolysis reactor where a carbon-based cathode is used to electrochemically convert the sparged O 2 to H 2 O 2 . The electro-generated H 2 O 2 then reacts with sparged O 3 to produce OH, which can rapidly oxidize pollutants in the bulk solution. When boron-doped diamond (BDD) electrodes were used as the anode, perchlorate concentrations increased significantly from undetectable levels to ∼15–174 mg L −1 in the different water samples as the applied current density was increased from 4 to 32 mA cm −2 . In contrast, no ClO 4 − was detected when Pt/Ti anodes were used in the E-peroxone process operated under similar reaction conditions. In addition, when sufficient O 3 was sparged to maximize OH production from its peroxone reaction with electro-generated H 2 O 2 , the E-peroxone process with Pt/Ti anodes achieved comparable clofibric acid degradation and total organic carbon (TOC) removal yields as that with BDD anodes, but did not generate detectable ClO 4 − . These results indicate that by optimizing operational parameters and using Pt/Ti anodes, the E-peroxone process can achieve the goal of both fast pollutant degradation and ClO 4 − prevention during the treatment of chloride-containing wastewater. [ABSTRACT FROM AUTHOR]

The steel-concrete interface determines the steel corrosion and the durability of concrete structures. In this paper, the relationship between macropores and localized corrosion is quantified, based on the natural deterioration of 5 wt% Cr steel reinforced mortar and laboratory tests of 5 wt% Cr steel in the saturated calcium hydroxide solution. The results show that, considering environmental factors with the same chloride content and water saturation, large interfacial macropores are always the weakest zones at which both corrosion initiation and propagation preferentially take place. The localized rate of steel corrosion (mm/year) increases linearly with the logarithm of the macropore volume (μL), and the slopes are in the range of 0.05–0.11 depending on the chloride level. The weakened pH buffering effect of solid Ca(OH) 2 at interfacial macropores is not the only reason for this phenomenon; the impacts of macropores and their volume on the electrochemical corrosion process are also significant. In small macropores, both cathodic and anodic polarizations are strengthened, and the thermodynamic driving force of the iron dissolution reaction is reduced. [ABSTRACT FROM AUTHOR]

This paper investigates the mixing phenomena in pipe junctions in water distribution systems. Network simulation models frequently assume that mixing at pipe junctions is complete and instantaneous. In the present study, a series of experiments using tee and cross junctions with varying inflows and free chlorine concentrations were carried out in the Hydraulic Laboratory of the Institute of Engineering at the National Autonomous University of Mexico. Numerical simulations of these experiments were also performed using EPANET-BAM. Experimental results from this study showed that mixing is not complete in most of the cases; intersecting flows tend to bifurcate rather than mix completely. Numerical simulations indicated good agreement between calculated and measured values. The model was also tested using data from the water distribution system of Duberger-Les Saules, in Quebec City, Canada. A larger vulnerability zone was identified due to the impact of the incomplete mixing at the cross junction in the prediction of chlorine residual in a water distribution network. [ABSTRACT FROM AUTHOR]

In the years 2013-2014 we evaluated changes in concentrations of chlorides and sulphates in waters of the National Nature Reserve Čičov oxbow depending on the time and place of sampling. Collections of samples were realized regularly at monthly intervals, always in the half of a month. Sampling sites were determined in order to assess the impact of natural and anthropogenic source of surface water quality. In order to evaluate the quality of surface water in the sampling sites by individual indicators, we used the values of the 90th percentile (P90), which was calculated from the measured values and then compared with their matching set of limit values referred to the Regulation of the Government of the Slovak Republic No. 269/2010 Coll. According to that Regulation, the recommended value for chlorides is 200 mg dm;; and for sulphates 250 mg dm−3. Based on the calculated values of 90th percentile (P90) of these indicators, we found out that the calculated characteristic values are lower. [ABSTRACT FROM AUTHOR]

Groundwater contaminants, such as chloride from road salt, pose a threat to aquatic ecosystems when and where they discharge to surface waters. Here we study the application of a laboratory toxicity bioassay to field-collected samples from contaminated groundwater discharging to an urban stream. The objectives were to assess the potential toxicity of the discharging groundwater, while also exploring the suitability of such standard tests to site groundwater. Juvenile freshwater mussels were chosen as a groundwater-appropriate (endobenthic) test organism. Groundwater was sampled from 6 sites at approximate depths of 0, 10, and 50 cm below the sediment. Concentrations of chloride and several metals were above aquatic life guidelines in some samples. Exposure (96-h) to site groundwater resulted in survival of 90–100% and 80–100% for the 0-cm and deeper samples, respectively, indicating that groundwater may pose a toxicological threat to freshwater mussels. Several samples with high chloride had a survival rate of 80%, but generally there was poor correlation between survival and individual contaminants. Parallel juvenile mussel exposures using reconstituted water and NaCl predicted survival in the natural groundwater below 50% based on chloride concentrations. This indicates some protective ability of groundwater, possibly associated with water hardness. Finally, some technical issues with performing bioassays with groundwater were noted. First, aeration of previously anoxic groundwater samples caused marked changes in water quality (especially metal concentrations). Second, calcite crystals formed on the mussel shells in samples with elevated chloride and water hardness, though with no apparent negative effects. [ABSTRACT FROM AUTHOR]

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. [ABSTRACT FROM AUTHOR]

This paper examines the identification of key indicators that could be used to measure the success of reclamation plants in post-exploration oil and gas mining areas. The main objective of this research was to find key indicators or variables for evaluating the level success of reclamation results in the post-mining of oil and gas area. In this study, 44 environmental variables of the physical, biological, soil, water and air indicators were analyzed from 70 field plots of 6 reclamation and 2 natural forest sites. The analysis methods included (1) cluster analysis using the Agglomerative Hierarchical Clustering method with the Ward's method, and (2) quadratic discriminant analysis. The results of the clustering analysis showed that there were some clusters due to variation of biomass, water, soil and air conditions. The three clusters developed based on water and/or air variables provided high cophenetic correlation (0.80) with low within-cluster (14.5%) and high between-cluster variations (85.5%). Based on the multicollinearity analysis, average vector difference test, variance matrix variance test, unidimensional test of each variable and quadratic discriminant function, this study found that there were 3 key indicators determining variations of the quality of the reclamation plantations within the study sites, namely, biological indicator of biomass volume (Bio_B); soil indicator of P content in the soil (Tnh_P), saturation base of soil (Tnh_Kb), Manganese (Mn) content in the soil (Tnh_Mn), Sulfur content in the soil (Tnh_S), percentage of ash in the soil (Tnh_Ab), percentage of clay in the soil (Tnh_Li), and water indicator of chloride content in the surface water (Air_Cl). The examination on four classes of the reclamation quality showed that the classes were successfully classified having excellent crossvalidation error matrix with overall accuracy more than 90%. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wetland indicators and trends are important for monitoring progress targets environmental sustainability development. Cheremske Lake, which is part of the hydrographic network of wetlands of the Cheremsky Nature Reserve, was explored. The territory is located in the northern part of the Manevichi district of Volyn region on the border with Rivne region. Cheremske Lake is of glacial karst origin, with a total area of 7.7 hectares. The purpose of the study is to analyze the hydrochemical parameters of Cheremske Lake to identify the ecological features of the formation of modern surface water quality of wetlands during the summer limit. Water samples from the Cheremske Lake were selected in August 2018 at 5 water points, from a depth of 0.5 m, using a bathometer. For the assessment of the ecological status of the studied lake, the samples were subjected to chemical-analytical control, which was carried out in the laboratory of water quality of the National University of Water and Environmental Engeneering (Rivne), in accordance with regulatory requirements. The general ecological assessment of water provided an assessment of the hydrochemical parameters of water according to three blocks of indicators: block of salt composition (chlorides, sulfates), block of tropho-saprobiological (sanitaryhygienic) composition (pH, ammonium, ammonium nitrogen, nitrites, nitrite nitrite, phosphates, suspended solids, PO, BOD5, content of oxygen dissolved in water, degree of saturation of water with oxygen) and block of specific substances of toxic effect (iron total, copper, zinc, manganese). The results of the measured concentrations of dissolved oxygen in the water were used to calculate the ratio of production of organic matter (P) to its destruction (D), which reflects the balance of organic matter in the reservoir. The analysis was carried out in a photic layer of water by the method of oxygen glasses. During the summer limit, at an average water temperature of 24.3 ºС, statistically significant exceedances of fishery standards of ammonium (3.98 ± 0.34 times), nitrogen of ammonium (3.10 ± 0.25), overlying substances (8 , 62 ± 1,17), indicators of permanganate oxidation and BSC5 (5.2 ± 0.42 and 11.96 ± 1.48 times, respectively), total iron content (31.66 ± 0.85), copper (500, 0 ± 16.96) and zinc (304.0 ± 21.78 times). Four of the nineteen hydrochemical parameters analyzed had the highest degree of purity by category. In particular, the water content of chlorides, sulfates, suspended solids and dissolved oxygen in Cheremske Lake is characterized as "very pure". By the content of nitrites, nitrite nitrogen and the degree of saturation of water with oxygen - "pure", and the content of nitrates and nitrogen nitrate as a transition from "pure" to "contaminated". The category "contaminated" included lake water such hydrochemical parameters as the reaction of the pH, phosphates and manganese. The content of ammonium ions, ammonium nitrogen, and iron in the general classify water as "dirty". The PO and BOD5 indicators, as well as the copper and zinc content in the water, gave it a qualitative environmental characteristic as "very dirty". Noteworthy is the fact that the worst quality water quality characteristics of certain categories were those of a block of specific toxic substances. At all checkpoints, they gave qualitative signs to the water of the lake with a state of "bad" and with a degree of purity "dirty". The tropho-saprobiological block of substances characterized mainly the state of water as “satisfactory” with a degree of purity “slightly contaminated”. The reduction of the obtained categories to the class of water quality by blocks of substances relates the general ecological status of the Cheremske Lake to III class, which testifies to the “satisfactory” state and the degree of purity of the water “contaminated”. At the same time, the production and destruction of organic matter in the photic layer of the lake were determined using the oxygen glass method. The results obtained indicate the relative stability of production and destruction processes in the photic layer of water, since the ratio of production to destruction is as close as possible to 1. Thus, at a depth of 0.5 m from the water surface, this value was 1.014, and at a depth of 1.5 m - 1,115 th most common Such values may reflect the relatively complete balance of the circulation of substances in the aquatic ecosystem with the autochthonous introduction of organic matter. In this case, the value of the gross primary production in the photic layer allows us to estimate the trophic level of the reservoir as “moderate” and the net primary production as “very low”. Given the high values of PO and BOD5, it can be argued that the decomposition of such organic matter is as complete as possible, which in turn gives an explanation for the high concentrations of ammonium, ammonium and phosphate ions present in the water. Since nitrates and nitrate nitrate had a slightly higher category than nitrite and nitrite nitrogen, it can also be predicted that oxidation processes play a decisive role and provide self-purification of the lake during the summer boundary. In our opinion, significant concentrations of total iron, copper and zinc create the specific chemical composition of surface waters of the Cheremske Lake, however, being essential elements does not pose a threat to the aquatic ecosystem. Thus, in the course of the research it was found that the nature of productiondegradation processes in the aquatic ecosystem is closer to the balance with the introduction of autochthonous organics. The assumption is made about the completeness of self-cleaning processes against the background of the unique chemical composition of surface waters, which is formed due to the local geochemical background and the wetland feeding of the studied lake. [ABSTRACT FROM AUTHOR]

The following study is aimed to determine the effect of rainfall on the quality of the groundwater in the Delhi-NCR region. Samples of groundwater were collected from a total of 10 sampling stations during the prerainfall/(June-July 2019) and post-rainfall (November-December 2019) seasons for the analysis of water quality parameters suggested by the World Health Organization. Lab tests were conducted to determine various physiochemical parameters of the water sample namely pH, Chloride (Cl-), Calcium Hardness (CH), Total Hardness (TH), Sulphate (SO4--), Nitrate (NO3-), Fluoride (F-) and Total Dissolved Solids (TDS). The Water Quality Index was then calculated and a brief comparison with the permissible values was also performed. The results show that most of the studied water sample were of poor quality in the case of post-rainfall collected water samples. [ABSTRACT FROM AUTHOR]

• Supercooling and the distribution of unfrozen pore water in frozen soil are analyzed. • A theoretical model for calculating the unfrozen water content of saline soil is proposed. • The influence of parameter in model and supersaturation degree on the calculation of unfrozen water content are discussed. The amount of unfrozen water reflects the soil water potential and is of importance to explore the water/salt migration in saline soil. Using low-field NMR technology, we measured the amount of unfrozen water content in sodium chloride soil under several initial salt contents. The results reveal that there are two phase transition processes in sodium chloride soil between 20 to −30 °C, the unfrozen water content decreases as ice crystals form in the first phase transition stage, and further decreases as ice and hydrated salt precipitate in the second phase transition stages. Supercooling phenomenon, caused by ice nucleation, delays the ice formation in the freezing process, thus leads to variation of unfrozen water content in soil. Through distribution of the unfrozen pore water in soils, we find that water in large pores is prone to freeze into ice. Considering the real phase transition process of soil, we propose a theoretical model to evaluate the unfrozen water content of sodium chloride soil at a wide temperature range. Not only unfrozen water content is well predicted in the two phase transition stages, but also the change of eutectic temperature can be explained under different initial salt concentrations. Based on this model, we discuss the influence of our parameter α and the supersaturation degree on our calculated results. This work provides a theoretical reference for investigating the deformation mechanism of saline frozen soil. [ABSTRACT FROM AUTHOR]

Summary Knowledge of atmospheric chloride deposition is a prerequisite for applying the chloride mass balance (CMB) method for groundwater recharge estimation. Compared to bare areas, vegetated areas can significantly enhance chloride deposition rates as the vegetation canopy provides a large surface onto which water droplets and aerosols settle. Although generally acknowledged, this effect has often been ignored in practical applications of the CMB method. This paper studies the variability of chloride deposition in a coastal basin characterised by a heterogeneous vegetation cover, and the implications of this variability for groundwater recharge estimation using observation wells in the saturated zone. The study area is located on the Eyre Peninsula in South Australia. The theory of the CMB method for groundwater recharge estimation is revised in the context of highly spatially variable chloride deposition. A GIS-based approach is developed for mapping the chloride deposition accounting for distance from the coast, distribution of vegetation and edge effects; the latter implying a lower chloride deposition inside a vegetation stand than at the edge. In order to quantify the significance of one or several of these effects for recharge estimation, different chloride deposition maps and corresponding recharge estimates are derived. Compared with the reference scenario that accounts for all effects, neglecting the coastal effect results in a 33–36% higher average recharge estimate, whereas neglecting the vegetation effect results in a 17–22% lower average recharge estimate. The latter numbers are likely to represent a lower bound of the impact of neglecting the vegetation effect. A critical factor for accurate determination of the influence of vegetation appears to be the edge effect, albeit its importance is subject to significant uncertainty that warrants further monitoring. [ABSTRACT FROM AUTHOR]

Accurate prediction of solute transport processes in surface water and its underlying bed is an important task not only for proper management of the surface water but also for pollution control in these water bodies. Key issue in this task is an estimation of parameters as diffusion coefficient and velocity for solute transport both in water body and in the underlying bed. This estimation would greatly help us to understand the deposition and release mechanism of solute across the water-bed interface. In this study, a column experiment was conducted in laboratory to estimate the velocity and diffusion coefficient of sodium chloride (NaCl) in water body and underlying sand layer (bed). The column used with a diameter of 30 cm and a height of 100 cm, was filled with sand at the lower half part and water at the upper half part. Total 64 stainless steel electrodes were installed on its surface around. The sodium chloride solution was injected from the top of the column, and electrical resistance between electrodes was monitored for 71 h. Then the dimensionless resistance breakthrough curve was fitted with one dimensional analytic solution for solute transport and the related diffusion coefficient and velocity parameters were estimated. The results show that the NaCl transport velocity was high in the water body but extremely low in the underlying sand layer (bed). The diffusion coefficient estimated in sand layer coincides with those reported well. This indicates that the electrical resistance based solute transport parameter estimation method is not only effective but also has an advantage of multipoints monitoring. This is useful both in mapping solute transport parameter for solute transport process analysis and in providing parameter input for solute transport numerical modeling. [ABSTRACT FROM AUTHOR]

Groundwater of Chapai Nawabganj town has been studied using hydrogeological, hydrochemical and environmental isotope (δ18O, δ²H, δ13C, ³H and 14C) data. Aquifer underneath the study area is divided into unconfined to semi-confined Holocene alluvial floodplain aquifer and confined Plio-Pleistocene Dupi Tila sandstone aquifer. Chemical composition of groundwater is characterized by high concentrations of Mg2+, Na+, Ca2+, HCO3-, FeTotal, and low concentrations of Mn2+, NO3- and PO43-. Groundwater samples are mainly Mg-Ca-HCO3 and Na-Mg-Ca-HCO3 types and Na-Mg-Ca-Cl-HCO3 type of water is also found at some places. Based on Cl- and SO42- concentrations groundwater is normal chloride and normal sulphate water, respectively. In terms of SAR and EC values water is excellent for irrigation purpose. The isotopic composition also suggests some segregation of groundwater from the different aquifers and indicates different ages of recharge. [ABSTRACT FROM AUTHOR]

The objective of this study was the visualization of the migration of a dissolved substance in the liquid water of wood during drying by means of X-ray imaging. The formation of a characteristic deposition pattern has been observed in the course of drying small pieces of sugi soaked in a cesium chloride (CsCl) aqueous solution. Expectedly, CsCl migrated from the inside to the surface and was deposited just below the surface because of the evaporation of water at the evaporation front. At the end of the drying process, the relative concentration of CsCl at the surface of sapwood samples was determined to be 130%-400% of the initial amount of dissolved CsCl, while the CsCl concentration deep inside samples was below 50%. Sapwood accumulated more CsCl than heartwood did, and the CsCl concentration in latewood was higher than in earlywood. [ABSTRACT FROM AUTHOR]