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An assessment of hysteresis in studies on the hydraulic conductivity of peat soils

100%

Brzostowski E., Olszta W.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The value of hydraulic conductivity (K) has considerable theoretical and practical significance for the water economy of soils and plants. Measurements of hydraulic conductivity conducted for peat soils in the process of soil monolith drying and wetting indicated the occurrence of capillary hysteresis in the soils under study. Data presented in the paper may indicate that the phenomenon is directly affected by the physical-hydraulic properties of the soils. The hysteresis loop surface areas determined in the study may be insufficient to fully reflect the true situation as there is a lack of measurements of the soil water potential in the zone close to full saturation. Values of the surface area calculated according to statistical methods differ from values calculated according to Brooks and Corey’s formulae. A significant factor affecting the difference is the value of effective conductivity (Kₑ) which is one half of the conductivity at full saturation (Ks).

2

Pedotransfer function for determining saturated hydraulic conductivity using artificial neural network (ANN)

100%

Kruk E., Malec M., Klatka S., Brodzinska-Cygan A., Kolodziej J.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2017

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tom 16

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nr 4

3

Verification of the Van Genuchten method of determination of the hydraulic conductivity of peat soils

100%

Olszta W., Kowalski D.

International Agrophysics

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1996

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tom 10

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nr 2

4

Method to estimate water permeability functions of moderately wet soils with help of heat pipe technique

88%

Globus A. M., Gee G. W., Fayer M., White M.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

Water permeability of moderately wet soils, i.e., their unsaturated hydraulic conductivity and water diffusivity are seldom measured directly, yet are often needed by numerical models to simulate transport processes. These functions can be evaluated from steady state water content and temperature profiles in heat pipes - closed columns of uniformly moistened soil subjected to temperature gradient. For such systems Sw = DT/D(θ) = -dθ/dT where Sw is the thermogradient coefficient, DT is the thermal water diffusivity, D(θ) is isothermal water diffusivity and dθ/dT is the rate of change of water content with temperature deduced from steady state profiles of θ(x) and T(x), x - is the distance from one of column ends. DT varies in a relatively narrow range and can be assumed as a constant.Then D(θ) can be estimated as DTSw where Sw is measured in various locations along soil columns. Using water retention data, the steady water content profile can be procedure for estimating D(θ) can then be applied to estimate hydraulic conductivity, K(θ). Soil columns ranging in length from 5 to 10 cm, exposed to thermal gradients of l°C/cm for periods as short as 7 d, at initial suction values ranging from 1 to 1.5 MPa, can be used to estimate D and K with uncertainties of factor of five or less in the suction range from 0.03 to 3 Mpa.

5

A new technique for hydraulic conductivity testing of expansive unsaturated soils

88%

Zakowicz S., Garbulewski K.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

A number of factors are known to influence the hydraulic conductivity (K) of soils. While a large number of laboratory and field methods have been developed over the years, most of them are applicable mainly for the measurement of hydraulic properties in saturated soils. Moreover, those methods omit such factors affecting hydraulic conductivity as soil volume changes (swelling or shrinkage) and external load simulating the location of the soil tested. The purpose of this paper is to present direct and simple methods for estimation of hydraulic properties, mainly conductivity of unsaturated soils. The methods proposed are based on evaluation of soil-water potential and water outflow from a soil sample. The test methods allow the 1- and 3-dimensional stress states of the soil and pore-fluid to be monitored. The procedure allows also to monitor the changing soil moisture using the TDR technique. The modified apparatus (triaxial apparatus, consolidometer and tempe pressure cell), soils and procedures are described first, and then the results of tests are presented and reviewed. Interpretation of test results is made using the Multi-step method. Results obtained showed that the stress states simulating the location of soil affected the hydraulic parameters significantly. The test results confirmed the usefulness of the methods proposed for testing the porous medium with the geometrical changes of soil (swelling/shrinkage) considered.

6

Hydraulic conductivity of a geosynthetic clay liner

88%

Bouazza A., Van Impe W. F., Menge P.

Przegląd Naukowy Wydziału Melioracji i Inżynierii Środowiska

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1996

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nr 12

7

Changes in the hydrophysical properties of peat soils under anthropogenic evolution

88%

Rovdan E., Witkowska-Walczak B., Walczak R., Slawinski C.

International Agrophysics

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2002

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tom 16

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nr 3

8

Evaluation of soil-geotextile behaviour using gradient ratio test

75%

Lechowicz Z., Krzywosz Z., Wojtasik D.

Annals of Warsaw Agricultural University. Land Reclamation

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2004

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tom 35a

9

Hydraulic conductivity of model landfill liner

75%

Garbulewski K.

Annals of Warsaw Agricultural University. Land Reclamation

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2004

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tom 35a

10

Capacity of textile filters for wastewater treatment at changeable wastewater level - a hydraulic model

75%

Spychala M., Pawlak M., Nawrot T.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2016

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tom 15

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nr 4

11

Scaling the hydraulic functions of a water repellent sandy soil

75%

Stoffregen H., Wessolek G.

International Agrophysics

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2014

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tom 28

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nr 3

The heterogeneity of both unsaturated hydraulic conductivity and water retention was measured with a high spatial resolution on a transect using an evaporation method. Fifteen undisturbed 100 cm 3 soil cores were taken on a transect every 10 cm from the topsoil of a water repellent sandy site. Five dynamic water retention curves and four unsaturated conductivity curves were determined for each core. We conducted measurements without further saturation in the laboratory in order to achieve field-like conditions. The initial water contents were hetero- geneous, indicating different hysteretic conditions and water repellent areas. The scattering of the water retention curves was high, while the heterogeneity of unsaturated conductivity curves was unexpectedly low. Two scaling approaches were used to describe the heterogeneity: one with and one without considering hysteresis. The concept of scaling applies well to describing the heterogeneity of both hydraulic functions. Including hysteresis leads to similar results than excluding hysteresis. The distribution of the hydraulic conductivity and the water retention were inde- pendent from each other. The results give important information for numerical simulation of the water flow with heterogeneous hydraulic functions.

12

Estimating time steps for the method of finite differences based on verification of the water balance

75%

Reinhard A.

Journal of Water and Land Development

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2004

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nr 08

13

Hydraulic performance of zero-valent iron and nano-sized zero-valent iron permeable reactive barriers-laboratory test

75%

Fronczyk J., Pawluk K.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2014

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tom 46

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nr 1

The hydraulic conductivity of zero-valent iron treatment zone of permeable reactive barriers (PRBs) may be decreased by reducing the porosity caused by gas production and solids precipitation. The study was undertaken in order to evaluate the influence of chloride and heavy metals on the hydraulic conductivity of ZVI and nZVI using hydraulic conductivity tests as well as continuous column tests. Results show that the lead retention in the solution had no impact for hydraulic conductivity in ZVI sample, on the other hand the calculated hydraulic conductivity losses in nZVI sample (from 4.10·10–5 to 2.30·10–5 m·s–1) were observed. Results also indicate that liquids containing the mixture of heavy metals may cause signifi cant decrease in hydraulic conductivity (from 1.03·10–4 to 1.51·10–6 m·s–1). During the column tests, several number of clogging of the reactive material caused by iron hydroxides precipitation was observed over the course of injection of heavy metals solution. In contrast, the hydraulic conductivity of ZVI and nZVI is unaffected when they are permeated with chloride ions solution (k = 1.03·10–4 m·s–1). Finally, the results indicate the need to take account of changes in the hydraulic conductivity of reactive materials for successful implementation of PRBs technology.

14

Hydraulic conductivity of a layered soil profile measured by ponded infiltration technique

75%

Szejba D., Kladivko E. J., Willoughby G. L.

Przegląd Naukowy Wydziału Melioracji i Inżynierii Środowiska

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1998

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nr 15

15

Accessibility of most frequently used physical parameters of soil structure, reliability of measured values, lack of replicates and ways out of this dilemma

75%

Hartge K. H.

International Agrophysics

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1997

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tom 11

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nr 1-2

16

Infiltration into layered soil covered with a depositional seal: a Green-Ampt approach

75%

Pachepsky Y. A., Timlin D.

International Agrophysics

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1996

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tom 10

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nr 1

17

Verification of the Van Genuchten method of determination of the hydraulic conductivity of selected moorshed peat soils

75%

Brzostowski E., Kowalski D., Olszta W.

Journal of Water and Land Development

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1999

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nr 03

The knowledge of hydraulic conductivity in unsaturated zone K(h) has a great theoretical and practical importance for soil water balance. The existing measurement methods of that parameter are rather complicated, so increasing interest appears in alternative, calculation methods. The article presents the results of laboratory tests of hydraulic conductivity of selected samples of peat soils, by dried monoliths method, and their comparison with calculated values obtained by Van Genuchten's formula with Mualem, Burdine and Brutsaert variation.

18

Effect of uniaxial compression on water retention, hydraulic conductivity and the penetration resistance of six Greek soils

75%

Panayiotopoulos K. P., Salonikiou E., Siaga K., Germanopoulou V., Skaperda S.

International Agrophysics

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2003

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tom 17

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nr 4

19

Przewodnosc hydrauliczna osrodka porowatego w ujeciu statystycznym

63%

Usowicz B.

Acta Agrophysica

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2001

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tom 53

177-187

20

Verification of determination of hydraulic conductivity for coarse soils by empirical formulas based on the density index

63%

Jaskiewicz K., Godlewski T.

Acta Scientiarum Polonorum. Architectura

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2021

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tom 20

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nr 2

Ograniczanie wyników

An assessment of hysteresis in studies on the hydraulic conductivity of peat soils

Pedotransfer function for determining saturated hydraulic conductivity using artificial neural network (ANN)

Verification of the Van Genuchten method of determination of the hydraulic conductivity of peat soils

Method to estimate water permeability functions of moderately wet soils with help of heat pipe technique

A new technique for hydraulic conductivity testing of expansive unsaturated soils

Hydraulic conductivity of a geosynthetic clay liner

Changes in the hydrophysical properties of peat soils under anthropogenic evolution

Evaluation of soil-geotextile behaviour using gradient ratio test

Hydraulic conductivity of model landfill liner

Capacity of textile filters for wastewater treatment at changeable wastewater level - a hydraulic model

Scaling the hydraulic functions of a water repellent sandy soil

Estimating time steps for the method of finite differences based on verification of the water balance

Hydraulic performance of zero-valent iron and nano-sized zero-valent iron permeable reactive barriers-laboratory test

Hydraulic conductivity of a layered soil profile measured by ponded infiltration technique

Accessibility of most frequently used physical parameters of soil structure, reliability of measured values, lack of replicates and ways out of this dilemma

Infiltration into layered soil covered with a depositional seal: a Green-Ampt approach

Verification of the Van Genuchten method of determination of the hydraulic conductivity of selected moorshed peat soils

Effect of uniaxial compression on water retention, hydraulic conductivity and the penetration resistance of six Greek soils

Przewodnosc hydrauliczna osrodka porowatego w ujeciu statystycznym

Verification of determination of hydraulic conductivity for coarse soils by empirical formulas based on the density index