A Predictive Model for Time Domain Reflectometry Soil Water Content and Salinity Measurements PDF Download
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Author: Benjamin A. Flugstad
Publisher:
ISBN:
Category : Soil moisture
Languages : en
Pages : 236
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Book Description
Soil water content and water potential are two important parameters in determining the status of water in the soil. Improvement in the ability to measure these parameters by way of increased speed, accuracy, resolution, imaging volume, ease of automation, as well as reduced calibration requirements and reduced soil disturbance would be of utility to many applications in agriculture and engineering. To make the measurements economically and without the use of hazardous materials or methods would also be of value. A brief review is given on most of the existing water content and water potential measurement techniques with focus given on electromagnetic and quantum mechanic techniques due to their potential for best balancing the design goals. A review of the theories of electromagnetics and quantum mechanics are presented with applications to soil water content and water potential measurements. One electromagnetic method, Time Domain Reflectometry, or TDR, shows great promise in balancing all the desired design goals. A mathematical model is proposed to be able to predict TDR water content and electrical conductivity (or salinity) measurement results over wide ranges of those parameters. Preliminary validations were performed on the model for both invasive and potentially non-invasive TDR probes in a sandy soil with the results showing good agreement between predictions and actual results but with some model refinements still needed. A proposal for ongoing research is given to refine the models and address the question on the feasibility of using the models in a field grade TDR instrument to measure water content and electrical conductivity (or salinity).
Author: Benjamin A. Flugstad
Publisher:
ISBN:
Category : Soil moisture
Languages : en
Pages : 236
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Book Description
Soil water content and water potential are two important parameters in determining the status of water in the soil. Improvement in the ability to measure these parameters by way of increased speed, accuracy, resolution, imaging volume, ease of automation, as well as reduced calibration requirements and reduced soil disturbance would be of utility to many applications in agriculture and engineering. To make the measurements economically and without the use of hazardous materials or methods would also be of value. A brief review is given on most of the existing water content and water potential measurement techniques with focus given on electromagnetic and quantum mechanic techniques due to their potential for best balancing the design goals. A review of the theories of electromagnetics and quantum mechanics are presented with applications to soil water content and water potential measurements. One electromagnetic method, Time Domain Reflectometry, or TDR, shows great promise in balancing all the desired design goals. A mathematical model is proposed to be able to predict TDR water content and electrical conductivity (or salinity) measurement results over wide ranges of those parameters. Preliminary validations were performed on the model for both invasive and potentially non-invasive TDR probes in a sandy soil with the results showing good agreement between predictions and actual results but with some model refinements still needed. A proposal for ongoing research is given to refine the models and address the question on the feasibility of using the models in a field grade TDR instrument to measure water content and electrical conductivity (or salinity).
Author: United States-Israel Binational Agricultural Research and Development Fund
Publisher:
ISBN:
Category :
Languages : en
Pages : 112
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Book Description
Author: Benjamin A. Flugstad
Publisher:
ISBN:
Category : Soil moisture
Languages : en
Pages : 433
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Book Description
Water conservation and water quality are rapidly increasing in importance in all areas of the world. The ability to accurately measure soil water content and salinity, over a wide variety of conditions, is key to meeting this need. A set of forward prediction models and waveform interpretation algorithms to extract Volumetric Water Content (WC) and Electrical Conductivity (EC) profiles vs. position and time for electrically lossy and dispersive geophysical and biological media are presented. These are applicable to both Time Domain and Frequency Domain Electromagnetic Wave Propagation Transmission and Reflection measurements. These forward prediction models are developed using physically based First Principles models from the Theory of Electromagnetics together with Scattering (S) Parameter and Transmission (T) Parameter network modeling techniques applied to wave propagation in various media with cascaded domains of different properties. The interpretation algorithms fit the pre-derived Forward Prediction models to the measurement data via lookup tables, interpolation and optimization methods. Presented applications include the transmission line methods of Time Domain Reflectometry, Time Domain Transmission, Frequency Domain Reflectometry and Frequency Domain Transmission including high dynamic range Frequency Domain Vector Network Analysis. Other applications include Ground Penetrating Radar and Microwave Remote Sensing. The models account for temporal and spatial heterogeneity to obtain WC and EC vs. time and position. Models are introduced for composite media with multiple constituents of varying Ohmic (EC) and dielectric (electric permittivity) properties accounting for dispersive frequency dependence and loss. These models interpolate between the physical upper and lower bounds of parallel and serial influences of each of the capacitive and conductive constituents. New models are also introduced accounting for charged interfaces and resulting bound and semi-bound water constituents within the pore spaces of soils containing clay or organic matter fractions resulting in a transition zone from bound to free water (via a semi-bound water zone) impacting the frequency dependence on electric permittivity. Validations of the models are presented via comparisons to actual measured data over wide ranges of water content, electrical conductivity and soil types.
Author:
Publisher:
ISBN:
Category : Soil moisture
Languages : en
Pages : 96
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Book Description
Author: Gordon C. Starr
Publisher:
ISBN:
Category :
Languages : en
Pages : 232
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Book Description
Author: Charles Etone Kome
Publisher:
ISBN:
Category : Hydrologic models
Languages : en
Pages : 344
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Book Description
Author: Olga Korostynska
Publisher: MDPI
ISBN: 3036504265
Category : Science
Languages : en
Pages : 350
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Book Description
It is impossible to imagine the modern world without sensors, or without real-time information about almost everything—from local temperature to material composition and health parameters. We sense, measure, and process data and act accordingly all the time. In fact, real-time monitoring and information is key to a successful business, an assistant in life-saving decisions that healthcare professionals make, and a tool in research that could revolutionize the future. To ensure that sensors address the rapidly developing needs of various areas of our lives and activities, scientists, researchers, manufacturers, and end-users have established an efficient dialogue so that the newest technological achievements in all aspects of real-time sensing can be implemented for the benefit of the wider community. This book documents some of the results of such a dialogue and reports on advances in sensors and sensor systems for existing and emerging real-time monitoring applications.
Author: David J. Mulla
Publisher:
ISBN:
Category : Runoff
Languages : en
Pages : 178
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Book Description
Author: Giulio Lorenzini
Publisher: WIT Press
ISBN: 1845640438
Category : Technology & Engineering
Languages : en
Pages : 417
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Book Description
Fresh water is becoming an ever increasingly precious commodity, control of which could lead in the near future to the type of political instability now associated with energy shortages. This book addresses the different aspects of irrigation, including not only the management of water resources and scientific and technical aspects, but also matters related to policy and economics, researchers in academia and industry as well as professional practitioners and policy makers. Bringing together papers from the First International Conference on Sustainable Irrigation Management, Technologies and Policies, the book covers topics such as: Irrigation Controls; Irrigation Modelling; Irrigation Systems and Planning; Irrigation Management.
Author: Johan Alexander Huisman
Publisher:
ISBN: 9789076894232
Category : Groundwater
Languages : en
Pages : 157
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Book Description
