Effects of Temperature on Measurements of Soil Water Content with Time Domain Reflectometry

Effects of Temperature on Measurements of Soil Water Content with Time Domain Reflectometry PDF Author: Tom Schanz
Publisher:
ISBN:
Category : Calibration
Languages : en
Pages : 8

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Book Description
This paper analyses the effects of temperature on the quantification of soil water content by means of time domain reflectometry (TDR) method. For this purpose, the dielectric constant of soil specimens with known water content was measured at different temperatures in a range of 20-80° C. The soil types used in the present study were fine sand, sand-bentonite mixture (SBM), and sandy loam. For each soil type, the dielectric constant of at least three specimens having identical dry density but varying initial water content was measured at temperatures ranging from 20 to 80° C. The results obtained agree with previous studies showing that there are two competing phenomena during the measurement of soil water content by means of TDR: (i) The soil bulk dielectric constant increases with increasing temperature due to the release of bound water from soil solid particles and (ii) the soil bulk dielectric constant decreases with increasing temperature due to the temperature effect of free water molecules. Moreover, it has an existing equilibrium water content at which both competing phenomena compensate each other. However, for the SBM no equilibrium water content was found, but the dielectric constant increased significantly with the temperature for the whole water content range. This can be explained by the significant clay content and the high specific surface area, which leads to a dominating effect of the increase of soil bulk dielectric constant with increasing temperature.

Effects of Temperature on Measurements of Soil Water Content with Time Domain Reflectometry

Effects of Temperature on Measurements of Soil Water Content with Time Domain Reflectometry PDF Author: Tom Schanz
Publisher:
ISBN:
Category : Calibration
Languages : en
Pages : 8

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Book Description
This paper analyses the effects of temperature on the quantification of soil water content by means of time domain reflectometry (TDR) method. For this purpose, the dielectric constant of soil specimens with known water content was measured at different temperatures in a range of 20-80° C. The soil types used in the present study were fine sand, sand-bentonite mixture (SBM), and sandy loam. For each soil type, the dielectric constant of at least three specimens having identical dry density but varying initial water content was measured at temperatures ranging from 20 to 80° C. The results obtained agree with previous studies showing that there are two competing phenomena during the measurement of soil water content by means of TDR: (i) The soil bulk dielectric constant increases with increasing temperature due to the release of bound water from soil solid particles and (ii) the soil bulk dielectric constant decreases with increasing temperature due to the temperature effect of free water molecules. Moreover, it has an existing equilibrium water content at which both competing phenomena compensate each other. However, for the SBM no equilibrium water content was found, but the dielectric constant increased significantly with the temperature for the whole water content range. This can be explained by the significant clay content and the high specific surface area, which leads to a dominating effect of the increase of soil bulk dielectric constant with increasing temperature.

Using Time Domain Reflectometry to Measure Frost Depth and Unfrozen Water Content in Soil

Using Time Domain Reflectometry to Measure Frost Depth and Unfrozen Water Content in Soil PDF Author: David J. Mulla
Publisher:
ISBN:
Category : Runoff
Languages : en
Pages : 178

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New Approaches to Soil Water Content Measurement Using Electromagnetic Methods

New Approaches to Soil Water Content Measurement Using Electromagnetic Methods PDF Author: Gordon C. Starr
Publisher:
ISBN:
Category :
Languages : en
Pages : 232

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Book Description


GeoMeasurements by Pulsing TDR Cables and Probes

GeoMeasurements by Pulsing TDR Cables and Probes PDF Author: Kevin M O'Connor
Publisher: CRC Press
ISBN: 9780849305863
Category : Science
Languages : en
Pages : 432

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Book Description
GeoMeasurements by Pulsing TDR Cables and Probes examines Time Domain Reflectometry (TDR) research and provides information on its use as a robust, reliable, and economical production tool. Common uses for TDR technology include telecommunications and power industries, but the text examines applications such as measurement of moisture of unsaturated soils; detection of fluids for leak and pollution; measurement of water levels for hydrological purposes; measurement of water pressures beneath dams; and deformation and stability monitoring of mines, slopes, and structures. Chapters discuss: basic physics of signal generation, transmission, and attenuation along the coaxial cable probe designs and procedures for calibration as well as the variation in probe responses to changes in water content and soil mineralogy variations in waveform characteristics associated with cable, deformation, cable calibration, and installation techniques for metallic cables in rock several cases demonstrating the use of TDR cables in soil as well as weathered and soft rock a rationale for the use of compliant cable in soil the use of metallic cable (MTDR) and optical fiber (OTDR) to monitor response of structures sensor/transducer components, connections from the sensors to the TDR pulser/sampler, and system control methods available software for transmission and analysis of TDR signatures The diverse interest and terminology within the TDR community tends to obscure commonalities and the universal physical principles underlying the technology. The authors seek to crystallize the basic principles among the seemingly divergent specialties using TDR technology in geomaterials. By examining varied experiences, GeoMeasurements by Pulsing TDR Cables and Probes provides a synergistic text necessary to unify the field.

Methods of Soil Analysis, Part 4

Methods of Soil Analysis, Part 4 PDF Author: Jacob H. Dane
Publisher: John Wiley & Sons
ISBN: 089118841X
Category : Technology & Engineering
Languages : en
Pages : 1744

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Book Description
The best single reference for both the theory and practice of soil physical measurements, Methods, Part 4 adopts a more hierarchical approach to allow readers to easily find their specific topic or measurement of interest. As such it is divided into eight main chapters on soil sampling and statistics, the solid, solution, and gas phases, soil heat, solute transport, multi-fluid flow, and erosion. More than 100 world experts contribute detailed sections.

Fundamentals of Geoenvironmental Engineering

Fundamentals of Geoenvironmental Engineering PDF Author: Abdel-Mohsen O. Mohamed
Publisher: Butterworth-Heinemann
ISBN: 0128051450
Category : Technology & Engineering
Languages : en
Pages : 710

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Book Description
Fundamentals of Geoenvironmental Engineering: Understanding Soil, Water, and Pollutant Interaction and Transport examines soil-water-pollutant interaction, including physico-chemical processes that occur when soil is exposed to various contaminants. Soil characteristics relevant to remedial techniques are explored, providing foundations for the correct process selection. Built upon the authors' extensive experience in research and practice, the book updates and expands the content to include current processes and pollutants. The book discusses propagation of soil pollution and soil characteristics relevant to remedial techniques. Practicing geotechnical and environmental engineers can apply the theory and case studies in the book directly to current projects. The book first discusses the stages of economic development and their connections to the sustainability of the environment. Subsequent chapters cover waste and its management, soil systems, soil-water and soil-pollutant interactions, subsurface transport of pollutants, role of groundwater, nano-, micro- and biologic pollutants, soil characteristics that impact pollution diffusion, and potential remediation processes like mechanical, electric, magnetic, hydraulic and dielectric permittivity of soils. - Presents a clear understanding of the propagation of pollutants in soils - Identifies the physico-chemical processes in soils - Covers emerging pollutants (nano-, micro- and biologic contaminants) - Features in-depth coverage of hydraulic, electrical, magnetic and dielectric permittivity characteristics of soils and their impact on remedial technologies

Principles and Applications of Time Domain Electrometry in Geoenvironmental Engineering

Principles and Applications of Time Domain Electrometry in Geoenvironmental Engineering PDF Author: A.M.O. Mohamed
Publisher: CRC Press
ISBN: 9780415411295
Category : Science
Languages : en
Pages : 636

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Book Description
Time domain electrometry (TDE) is a general term which includes time domain reflectrometry and time domain transmissiometry. It is a commercially-viable technique for leak detection, contaminant monitoring, and moisture content determination in contaminant transport modelling. Under demographic pressure, contaminated sites are increasingly being re-developed for domestic and industrial use; and this presents an urgent need for reliable, non-intrusive and integrated methods of subsurface characterization, detection and monitoring of organic and inorganic pollutants, soil moisture content and salinity. This book provides an overview of the potential application of TDE in geoenvironmental engineering and describes the geophysical methods used.

Measuring Soil Water Content with Time Domain Reflectometry and Ground-penetrating Radar

Measuring Soil Water Content with Time Domain Reflectometry and Ground-penetrating Radar PDF Author: Johan Alexander Huisman
Publisher:
ISBN: 9789076894232
Category : Groundwater
Languages : en
Pages : 157

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Soil Water Measurement

Soil Water Measurement PDF Author: J. David Cooper
Publisher: John Wiley & Sons
ISBN: 1119106028
Category : Science
Languages : en
Pages : 368

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Book Description
This book is written for all those involved in measurement of soil water phenomena, whether they be environmental scientists, field technicians, agronomists, meteorologists, hydrogeologists, foresters, physical geographers, civil or water engineers or students in these subjects. It contains a comprehensive description of all the major methods used for measurement of soil water content and potential, solute concentration, transport and balance of water and solutes, including recharge to groundwater aquifers. The emphasis is firmly on techniques which can be applied in the field or on samples obtained from the field. The theory and practice of the workings of the main instruments and methods available is described, along with practical tips on surmounting some of the main difficulties and explanations of many commonly encountered jargon words.

Measurement of Soil Water Content Using the Combined Time-domain Reflectometry-thermal Conductivity Probe

Measurement of Soil Water Content Using the Combined Time-domain Reflectometry-thermal Conductivity Probe PDF Author: Thomas Henry Williams Baker
Publisher:
ISBN:
Category : Soil moisture
Languages : en
Pages : 4

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Book Description