An equivalent salt solutions method for predicting hydraulic conductivities of soils for different salt solutions

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 423 ◽  
Author(s):  
NS Jayawardane
Keyword(s):  
Boundary Conditions ◽  
Salt Solution ◽  
Electrolyte Concentration ◽  
Alluvial Soil ◽  
Sodium Absorption ◽  
Pore Geometry ◽  
Specific Pressure ◽  
Salt Solutions ◽  
Sodium Absorption Ratio ◽  
The Relationship

Equivalent salt solutions are defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration producing the same extent of clay swelling in a given soil. It is suggested that in the presence of different equivalent salt solutions a given soil will have the same pore geometry, the same saturated and unsaturated conductivities at specific pressure heads, and hence the same capacity to transmit such solutions under specific boundary conditions. This concept of equivalent salt solutions was used to develop a method for predicting the saturated hydraulic conductivities of soils for different salt solutions. The basic data required for such predictions in a given soil are the equivalent salt solution values and the relationship between saturated conductivity and electrolyte concentration at a given SAR. Saturated conductivities of a red-brown soil and an alluvial soil for salt solutions of SAR 20 and 10 and different electrolyte concentrations predicted by this method were fairly close to measured values. The significance of this concept to field problems involving flow of the salt solutions through soils is briefly discussed.

Effect of salt solution composition on moisture release curves of soil

Soil Research ◽  
1979 ◽  
Vol 17 (1) ◽  
pp. 89 ◽  
Author(s):  
NS Jayawardane ◽  
JA Beattie
Keyword(s):  
Pore Size ◽  
Salt Solution ◽  
Electrolyte Concentration ◽  
Sodium Absorption ◽  
Alluvial Soils ◽  
Salt Solutions ◽  
Solution Composition ◽  
Sodium Absorption Ratio ◽  
Wide Range ◽  
Size Index

A pore size index was used to express quantitatively the relative decrease in size of common pore of confined columns of krasnozem, red-brown and alluvial soils, with reduction in electrolyte concentration of percolating solutions of a given sodium absorption ratio (SAR). The pore size index of red-brown and alluvial soils decreased markedly with reduction in electrolyte concentration, especially in solutions of high SAR. In the krasnozem soil the pore size index remained fairly constant for a wide range of salt solutions. Moisture release curves of red-brown soil for solutions of decreasing electrolyte concentration and constant SAR and for solutions of increasing SAR and constant electrolyte concentration can be used in combination to obtain moisture release curves of this soil for solutions at any intermediate values of SAR and electrolyte concentration. They also reveal the pattern of volume change of different sized pores.

Further examination of the use of the equivalent salt solutions method for predicting hydraulic conductivity of soils for different salt solutions

Soil Research ◽  
1983 ◽  
Vol 21 (1) ◽  
pp. 105 ◽  
Author(s):  
NS Jayawardane
Keyword(s):  
Hydraulic Conductivity ◽  
Satisfactory Agreement ◽  
Salt Solution ◽  
Solution Method ◽  
Domain Model ◽  
Sodium Absorption ◽  
Salt Solutions ◽  
Sodium Absorption Ratio ◽  
Model Method ◽  
Solution Methods

Hydraulic conductivities of Pachappa and Waukena soils for different salt solutions, predicted by the equivalent salt solution methods, showed satisfactory agreement with measured values. The values of equivalent salt solutions for these soils were calculated from macroscopic swelling values of extracted clays. The equivalent salt solution method and the simplified domain model method of McNeal predicted equally accurately, the changes in hydraulic conductivities of Pachappa soil in salt solutions with sodium absorption ratio values from 15 to 100.

Prediction of unsaturated hydraulic conductivity changes of a loamy soil in different salt solutions by using the equivalent salt solutions concept

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 565 ◽  
Author(s):  
NS Jayawardane
Keyword(s):  
Hydraulic Conductivity ◽  
Salt Solution ◽  
Electrolyte Concentration ◽  
Saline Water ◽  
Saturated Hydraulic Conductivity ◽  
Sodium Absorption ◽  
Published Data ◽  
Salt Solutions ◽  
Solution Series ◽  
Water Contents

Equivalent salt solutions series have been previously defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration (E,) producing the same extent of clay swelling in a given soil. These equivalent salt solutions series values have yielded satisfactory predictions of changes in saturated hydraulic conductivity, with changes in salt solution composition and concentrations. In the present study, previously published data on changes in saturated and unsaturated hydraulic conductivities of Gilat soil in salt solutions of cationic ratio 0-50 (mmol dm-3)1/2 and electrolyte concentration 2-50 (m.e. dm-3) were used to compare the equivalent salt solution series values for hydraulic conductivities at different water contents. The equivalent salt solution series causing a given change in saturated hydraulic conductivity of a loamy Gilat soil were derived. These equivalent salt solution values were used to predict the unsaturated hydraulic conductivities of this soil at low water contents. Predictions of unsaturated conductivity at relative water contents (�) ranging from 0.80 to 0.20 agreed closely with the measured values. Coefficients log a1 and b1 for Gilat soil, in the equation log Ec = log a1+b1 log SAR, relating the Ec and SAR values of each equivalent salt solutions series were determined at � values between 1.00 and 0.20. The relationship between log a1 and bl was similar at all water contents, in agreement with the equivalent salt solutions concept. Therefore, equivalent salt solution parameters derived from saturated hydraulic conductivity measurements could be used to predict changes in unsaturated conductivities and hence flow rates of saline water under specified boundary conditions.

scholarly journals Classification of groundwater suitability for irrigation purposes using a comprehensive approach based on the AHP and GIS techniques in North Kurdufan Province, Sudan

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Elsiddig Eldaw ◽  
Tao Huang ◽  
Adam Khalifa Mohamed ◽  
Yahaya Mahama
Keyword(s):  
Water Quality ◽  
Spatial Distribution ◽  
Groundwater Quality ◽  
Irrigation Water ◽  
Research Effort ◽  
Sodium Absorption ◽  
Irrigation Water Quality ◽  
Middle Income ◽  
Sodium Absorption Ratio ◽  
Deep Aquifers

AbstractDeterioration of groundwater quality due to drastic human interventions is rising at an alarming rate particularly in lower- and middle-income countries. Yet, limited research effort has been devoted to monitoring and ascertaining groundwater quality. The present study develops a comprehensive irrigation water quality index (IWQI) for rating water quality of shallow and deep aquifers in North Kurdufan province, Sudan. The new approach is developed to overcome the deficiencies of the existing irrigation indices and coming up with a unified decision for classifying water quality for irrigation purposes. Because of these indices like permeability index (PI), sodium absorption ratio (SAR), etc., depending on specific elements, entirely subjective, as well as the great variations in their results, particularly when classifying water quality. Thus, IWQI is created based on eight indices that are generally used to evaluate irrigation water quality, plus three physicochemical parameters have been proven an impact on water quality. The analytic hierarchy process (AHP) is applied to minimize the subjectivity at assign parameter weights under multiple criteria decision analysis tools (MCDA). The spatial distribution of IWQI agrees with the spatial distribution of the most parameters. The results of our approach reveal that the majority of samples are suitable for irrigation uses for both aquifers except few wells in the confined aquifer. Also, noted that there are very variations in the irrigation indices results for classifying water quality. The comparison result showed that the new index robust, fair calculations and has best classifying of water quality.

scholarly journals Comparison of the Concentration of Risk Elements in Alluvial Soils Determined by pXRF In Situ, in the Laboratory, and by ICP-OES

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 938
Author(s):  
Ladislav Menšík ◽  
Lukáš Hlisnikovský ◽  
Pavel Nerušil ◽  
Eva Kunzová
Keyword(s):  
Precision Agriculture ◽  
Alluvial Soil ◽  
Coefficient Of Determination ◽  
Fast Method ◽  
Agricultural Practice ◽  
Regression Equations ◽  
Icp Oes ◽  
Risk Elements ◽  
The Relationship

The aim of the study was to compare the concentrations of risk elements (As, Cu, Mn, Ni, Pb, Zn) in alluvial soil, which were measured by a portable X-ray fluorescence analyser (pXRF) in situ (FIELD) and in the laboratory (LABORATORY). Subsequently, regression equations were developed for individual elements through the method of construction of the regression model, which compare the results of pXRF with classical laboratory analysis (ICP-OES). The accuracy of the measurement, expressed by the coefficient of determination (R2), was as follows in the case of FIELD–ICP-OES: Pb (0.96), Zn (0.92), As (0.72), Mn (0.63), Cu (0.31) and Ni (0.01). In the case of LABORATORY–ICP-OES, the coefficients had values: Pb (0.99), Zn (0.98), Cu and Mn (0.89), As (0.88), Ni (0.81). A higher dependence of the relationship was recorded between LABORATORY–ICP-OES than between FIELD–ICP-OES. An excellent relationship was recorded for the elements Pb and Zn, both for FIELD and LABORATORY (R2 higher than 0.90). The elements Cu, Mn and As have a worse tightness in the relationship; however, the results of the model have shown its applicability for common use, e.g., in agricultural practice or in monitoring the quality of the environment. Based on our results, we can say that pXRF instruments can provide highly accurate results for the concentration of risk elements in the soil in real time for some elements and meet the principle of precision agriculture: an efficient, accurate and fast method of analysis.

Innovation in SMEs: the role of employee training in German SMEs

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Irem Demirkan ◽  
Ravi Srinivasan ◽  
Alka Nand
Keyword(s):  
Research And Development ◽  
Boundary Conditions ◽  
Product Innovation ◽  
Employee Training ◽  
Lower Proportion ◽  
Economic Research ◽  
Content Type ◽  
The Relationship ◽  
Practical Implications

PurposeThis paper explores the role of effective resource and knowledge management capabilities on product innovation capabilities of the small and medium-sized enterprises (SMEs). Specifically, the authors research the role of the human resource investments in the form of employee training in developing firm's innovation capabilities and how SMEs manage these investments when we account for the boundary conditions such as the level of employee education, SME size and the frequency of investments in research and development (R&D).Design/methodology/approachThe authors use survey data conducted by The Centre for European Economic Research (Zentrum für Europäische Wirtschaftsforschung – ZEW). The final sample for analysis includes 983 SMEs from Germany that belong to 13 different industries. The authors use hierarchical OLS regression to test the hypotheses presented in this paper.FindingsThe authors find a positive association between increased investments in employee training and product innovation capabilities in the context of SMEs. More specifically, the authors’ findings support that (1) the relationship between employee training and innovation capabilities is weaker in industries with greater proportion of employees with university degrees, (2) the effectiveness of investments in employee training is lower among larger SMEs than smaller SMEs, and (3) continuous R&D weakens the relationship between training expenditure and innovation capabilities. While on the one hand the authors’ findings contribute to the debate of whether employee training is necessary for SMEs by affirming this notion, on the other hand the authors show that investments in employee training have differing implications for small and large SMEs within boundary conditions. Moreover, these findings have practical implications for the managers of all SMEs in terms of management of their knowledge resources.Research limitations/implicationsThe authors’ research makes important contributions to the study of innovation in SMEs. First, the authors contribute evidence to the debate whether employee training is necessary for SMEs by showing that employee training is particularly important for SMEs that are smaller in size, have lower proportion of employees with university degrees and when they invest in research and development in a targeted manner. The authors also demonstrate that investments in employee training is not a waste, rather such investments can increase the likelihood of survival for many of these firms through its positive impact on product innovation.Practical implicationsFor managers of SMEs, the authors’ findings suggest that while investments in employee training are important, the managers of particular SMEs with above-mentioned qualities should be persistent in such investments and must make deliberate efforts to reap the benefits in terms of innovative capabilities. Unlike large firms, who have the financial means to carry out investments in an abundant manner, SMEs appear to be more enterprising with their scarce resources when we also consider the role of investments in human resources.Originality/valueThe authors’ research makes important contributions to the study of innovation in SMEs. First, the authors contribute evidence to the debate whether employee training is necessary for SMEs by finding that employee training is particularly important for SMEs that are smaller in size, have lower proportion of employees with university degrees and when they do not invest in R&D continuously. The authors also demonstrate that investments in employee training is not a waste, but such investments can increase the likelihood of survival for many of these firms.

scholarly journals A New Analysis of Ammonia and Sodium Transport Through the Gills of the Freshwater Rainbow Trout (Salmo Gairdneri)

1989 ◽  
Vol 142 (1) ◽  
pp. 155-175 ◽  
Author(s):  
MARTINE AVELLA ◽  
MICHEL BORNANCIN
Keyword(s):  
Sodium Transport ◽  
Proton Transport ◽  
External Medium ◽  
Ammonia Excretion ◽  
Gill Tissue ◽  
Ammonia Concentration ◽  
Salmo Gairdneri ◽  
Sodium Absorption ◽  
Ammonia Transport ◽  
The Relationship

The mechanism of ammonia excretion and sodium absorption was re-examined in trout using the isolated-perfused head preparation. Preliminary experiments in which ammonia concentration was increased on the blood side (internal) showed that ammonia and sodium transport was uncoupled. For ammonia excretion, our results showed that gill tissue endogenously produces ammonia. A correlation was demonstrated between ammonia excretion and the internal-external ammonia gradient. We conclude that diffusion in the form of NH3 was responsible for ammonia efflux and we were therefore able to estimate its diffusion coefficient (DNH3 = 1.55×10−6cm2s−1) and permeability coefficient (6×10−3cm s−1). This ammonia diffusion was shown to be modified according to the external proton availability. For sodium absorption, significant changes were caused by indirect modifications of intracellular pH brought about by addition of acetazolamide inside or ammonia outside or by acidification of the internal or external medium. The relationship between sodium and proton transport was further confirmed by the action of the drug amiloride and the measurement of H+ excretion. A possible model representing sodium, proton and ammonia transport through the gill epithelium is proposed.

scholarly journals Hydrochemical assessment of water quality for irrigation: A case study of the wetland complex of Guerbes-Sanhadja, North-East of Algeria

2018 ◽  
Vol 38 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Sihem Hedjal ◽  
Derradji Zouini ◽  
Abdelwaheb Benamara
Keyword(s):  
Water Quality ◽  
Quality Parameters ◽  
Irrigated Agriculture ◽  
Sodium Absorption ◽  
Sodium Absorption Ratio ◽  
North East ◽  
The Status ◽  
Wetland Complex ◽  
Eastern Algeria ◽  
Irrigation Quality

AbstractThe wetland complex of Guerbes-Sanhadja (north-eastern Algeria), has experienced in recent years a certain economic expansion, particularly agricultural, about 47% of the useful agricultural area marked by several varieties of crops ranging from market gardening to speculative crops, requiring large quantities of water for irrigation purposes, however the swampy areas are the main sources used for irrigation purposes in this practice. It is therefore necessary for this water to have physicochemical properties adapted to plants, in particular the absence of salinity. This study was done to evaluate the status of the swamps areas quality and its suitability for irrigated agriculture. To achieve this objective, water samples from ten swamps areas water were collected from Guerbes-Sanhadja in February and June of 2016. The water quality of these swamps was estimated from different water quality parameters such as pH and electrical conductivity (EC), the chemical parameters like Na+, K+, Ca2+, HCO3−, SO42−, Cl−, BOD5, NO3−, NO2−, NH4+ and PO43−. Based on the physico-chemical analyses, irrigation quality parameters like sodium absorption ratio (SAR), percent sodium (% Na), residual sodium carbonate (RSC), permeability index (PI), magnesium hazard (MH) were calculated. The results showed that the overall concentration of nitrate was very high. About 60 percent of the swampy areas had suitable water quality for chloride, and they had a concentration below the permissible limit for crop irrigation. From the Richards diagram, it is observed that most of the samples from the study area fall in the good to permissible classes for irrigation purpose.

Seeking feedback but unable to improve work performance? Qualified feedback from trusted supervisors matters

2015 ◽  
Vol 20 (1) ◽  
pp. 81-100 ◽  
Author(s):  
Eun Young Nae ◽  
Hyoung Koo Moon ◽  
Byoung Kwon Choi
Keyword(s):  
Boundary Conditions ◽  
Work Performance ◽  
Positive Influence ◽  
High Quality ◽  
Content Type ◽  
Moderating Factors ◽  
Feedback Quality ◽  
Seeking Behavior ◽  
The Relationship

Purpose – The purpose of this paper is to investigate the boundary conditions in the relationship between feedback-seeking behavior (FSB) and work performance. The authors hypothesized that the positive influence of employees’ FSB on their work performance is influenced by perceived quality of feedback. The authors also expected that employees’ trust in their supervisors moderated the interaction between their FSB and perceived feedback quality. Design/methodology/approach – Data were collected from 202 employees in South Korea. A hierarchical multiple regression analysis was performed to test the hypothesis. Findings – The results showed that while employees’ FSB was positively related to work performance, the influence was stronger for employees who perceived they were receiving high quality of feedback from supervisors. The authors also found that the moderating effect of feedback quality on the relationship between FSB and work performance was stronger when employees had high levels of trust in their supervisors. Practical implications – The findings suggest that if managers wish to encourage employees to achieve work goal and desirable performance levels by actively engaging in FSB, they should pay more attention to providing high quality of feedback and building trust with employees. Originality/value – This study contributes to expand the understanding of FSB-work performance relationship by verifying the boundary conditions, which suggests the importance of examining the moderating factors in the FSB mechanism.

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