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Temperature effects in soil water content determined with time domain reflectometry

100%

Halbertsma J., van den Elsen E., Bohl H., Skierucha W.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The relative permittivity of water decreases with increasing temperature. Therefore, it is likely that the soil water content determined with time domain reflectometry (TDR) is influenced by temperature. We derived a correction based on a refractive mixing model. Our field experiment on a peat soil and laboratory experiments on disturbed sand and loam samples showed that there exist significant temperature effects. The magnitude of these effects is a function of water content and temperature. Both the refractive mixing model-based correction and Ledieu’s correction compensated temperature effects reasonable well. We recommend Ledieu’s correction for its simplicity: only information of the soil temperature is needed to correct the measured water content. The model-based correction needs additional information of the TDR calibration function. Our laboratory experiments on disturbed clay samples however, did not show a temperature effect. We suggest that the electrical conductivity counteracts the temperature effects in clay.

2

Dielectric determination of moisture of cereals grain using time domain reflectometry

100%

Malicki M. A., Kotlinski J.

International Agrophysics

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1998

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tom 12

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nr 3

3

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.

4

Accuracy of soil moisture measurement by TDR technique

88%

Skierucha W.

International Agrophysics

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2000

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tom 14

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nr 4

5

Application of TDR measurement technology for construction materials in semi-scale experiments

88%

Pavlik Z., Cerny R.

International Agrophysics

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2004

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tom 18

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nr 3

6

Mathematical modelling of water movement in autoclaved concrete

75%

Janik G.

Acta Agrophysica

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2010

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tom 15

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nr 1[177]

The paper presents a mathematical model developed for the description of water movement in selected construction materials. In the creation of the model the Richards equation was employed that was introduced in 1931 for a homogeneous and isotropic soil medium. The equation was solved with the method of finite differences, using an explicit scheme. The experiment was conducted on a sample made of autoclaved cellular concrete in which TDR probes were placed for moisture measurement. Water movement in the sample was caused by capillary rise. Results from computer simulation were compared with those obtained in the experiment. It was demonstrated that the Richards equation can be used for the description of the dynamics of air-water conditions in cellular concrete. It was also found that differences between results obtained from the simulation and those obtained from the experiment could have been caused by the lack of calibration of the TDR apparatus that should be made individually for every medium.

7

TDR technique for estimating the intensity of effective non rainfall

75%

Janik G., Skierucha W., Blas M., Sobik M., Albert M., Dubicki M., Zawada A.

International Agrophysics

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2014

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tom 28

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nr 1

The objective of this paper is to present a method for determining diurnal distribution of the intensity of effective non rainfall water flux. It was found that the application of TDR technique for the determination of diurnal dynamics of effective non rainfall water flux requires temperature correction of sensed volumetric moisture contents. Without temperature correction the error of estimated non rainfall water flux can be as much as 26%. In addition, the effect of temperature changes on the soil surface was determined in 0.5, 1, 2, 3, 4, and 5 hours periods. It was found that the intensity of effective non rainfall water flux was determined to the greatest extent by the rate of temperature drop during the period of 3 h preceding the non rainfall water flux determination. The agreement of non rainfall water flux calculated with the method proposed and that obtained by the collector was better for dew than for hoarfrost periods.

8

Dielectric determination of moisture of wood using time domain reflectometry

75%

Malicki M. A., Kotlinski J.

International Agrophysics

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1998

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tom 12

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nr 3

9

Application of TDR measurement technology for construction materials in semi-scale experiments: A practical example

75%

Pavlik Z., Cerny R.

International Agrophysics

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2005

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tom 19

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nr 1

10

Soil water balance of an arid linear sand dune

75%

Rummel B., Felix-Henningsen P.

International Agrophysics

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2004

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tom 18

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nr 4

11

Comparison of Open-Ended Coax and TDR sensors for the measurement of soil dielectric permittivity in microwave frequencies

75%

Skierucha W., Walczak R., Wilczak A.

International Agrophysics

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2004

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tom 18

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nr 4

12

TDR and low-frequency measurements for continuous monitoring of moisture and density in a snow pack

75%

Stacheder M.

International Agrophysics

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2005

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tom 19

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nr 1

13

Measurement of water characteristics in soils using TDR technique: water characteristics of loess soil under different treatment

75%

Walczak R. T., Slawinski C., Malicki M., Sobczuk H.

International Agrophysics

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1993

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tom 07

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nr 2-3

14

An automatic time domain reflectometry device to measure and store soil moisture contents for stand-alone field use

75%

Van Den Elsen H. G. M., Kokot J., Skierucha W., Halbertsma J. M.

International Agrophysics

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1995

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tom 09

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nr 3

15

Comparison of deep seepage estimations of a virtual with a real lysimeter by means of TDR-measurements

75%

Schindler U., Mueller L.

International Agrophysics

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2005

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tom 19

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nr 1

16

Metoda wyznaczania strefy czułości sensorów TDR

63%

Janik G., Szpila M., Slowinska J., Brej G., Turkiewicz M., Skierucha W., Pastuszka T.

Acta Agrophysica

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2011

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tom 18

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nr 2[193]

W niniejszej pracy przedstawiono metodę wyznaczania strefy czułości sensorów stosowanych do pomiaru wilgotności objętościowej w ośrodkach porowatych. Analizom poddano czujniki wykorzystujące reflektometrię domenowo czasową (TDR), wyprodukowane w Instytucie Agrofizyki Polskiej Akademii Nauk w Lublinie. Na podstawie przeprowadzonych badań laboratoryjnych stwierdzono, że zasięg strefy czułości sensorów typu laboratoryjnego i polowego jest zależny od zawartości wody w ośrodku, w którym prowadzone są pomiary. W przypadku czujnika laboratoryjnego (LP/ms), gdy oznaczenia prowadzone są w glebie całkowicie suchej, strefę czułości stanowi objętość prostopadłościanu o wymiarach 0,6 cm i 5,8 cm i grubości równej średnicy prętów sondy LP. Natomiast gdy gleba jest nasycona to strefę czułości stanowi walec eliptyczny o wysokości 5,5 cm i promieniach 0,5 cm i 0,8 cm. W przypadku czujnika polowego (FP/mts), gdy pomiary prowadzone są w glebie całkowicie suchej, strefę czułości stanowi walec eliptyczny o wysokości 10,2 cm i promieniach 0,3 cm i 0,4 cm. Natomiast gdy gleba jest nasycona wodą walec o wysokości 11,2 cm i podstawie koła o promieniu 1,7 cm.

17

Influence of moisture and salinity of soil on its dielectric permittivity

63%

Wilczek A., Skierucha W., Szyplowska A.

Acta Agrophysica. Rozprawy i Monografie

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2011

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nr 6[197]

18

Diurnal dynamics of water intake by roots of celeriac

63%

Janik G.

Electronic Journal of Polish Agricultural Universities. Series Environmental Development

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2007

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tom 10

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nr 2

19

Impact of the moisture content in medium sands on CPTU test results

63%

Zawadzki L., Bajda M.

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

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2016

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tom 48

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nr 3

20

Time domain reflectometry as a tool for the estimation of quality in foods

63%

Kent M., Knochel R., Daschner F., Schimmer O., Oehlenschlager J., Mierke-Klemeyer S., Barr U. K., Floberg P., Tejada M., Huidobro A., Nunes L., Batista I., Martins A.

International Agrophysics

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2004

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tom 18

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nr 3

Ograniczanie wyników

Temperature effects in soil water content determined with time domain reflectometry

Dielectric determination of moisture of cereals grain using time domain reflectometry

A new technique for hydraulic conductivity testing of expansive unsaturated soils

Accuracy of soil moisture measurement by TDR technique

Application of TDR measurement technology for construction materials in semi-scale experiments

Mathematical modelling of water movement in autoclaved concrete

TDR technique for estimating the intensity of effective non rainfall

Dielectric determination of moisture of wood using time domain reflectometry

Application of TDR measurement technology for construction materials in semi-scale experiments: A practical example

Soil water balance of an arid linear sand dune

Comparison of Open-Ended Coax and TDR sensors for the measurement of soil dielectric permittivity in microwave frequencies

TDR and low-frequency measurements for continuous monitoring of moisture and density in a snow pack

Measurement of water characteristics in soils using TDR technique: water characteristics of loess soil under different treatment

An automatic time domain reflectometry device to measure and store soil moisture contents for stand-alone field use

Comparison of deep seepage estimations of a virtual with a real lysimeter by means of TDR-measurements

Metoda wyznaczania strefy czułości sensorów TDR

Influence of moisture and salinity of soil on its dielectric permittivity

Diurnal dynamics of water intake by roots of celeriac

Impact of the moisture content in medium sands on CPTU test results

Time domain reflectometry as a tool for the estimation of quality in foods