Experiments with a Fiber Optic Soil Moisture Sensor PDF Download

Author: Randolph Samuel Alessi
Publisher:
ISBN:
Category : Fiber optics
Languages : en
Pages : 192

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Author: Arlen M. Striegl
Publisher:
ISBN:
Category :
Languages : en
Pages : 240

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Author: Aisha B. Fields
Publisher:
ISBN:
Category : Optical fiber detectors
Languages : en
Pages : 106

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Category : Arctic regions
Languages : en
Pages : 28

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Author: Qiong Robert Wu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"One of the most challenging aspects of controlling contamination in mining operations is the management of tailings and waste rock piles. Waste rock is the material extracted from a mine that has no economic value and may be a source of contamination from acid or neutral mine drainage. Only in recent decades have mining operations incorporated covers in the design of waste rock piles to prevent the infiltration of water and oxygen, increase chemical stabilization, and minimize contaminant leachate. This thesis focuses on the distributed measurement of soil moisture in a waste rock pile using active fiber optic distributed temperature sensing (aFO-DTS). Soil moisture is measured by heating the metal casing of a fiber optic cable and evaluating the thermal response. This emerging geophysical method allows for the measurement of soil moisture continuously along several kilometers of fiber optic cable, with measurement spacing every half meter, and a temporal resolution of less than an hour per measurement. In this thesis, I undertake three projects: (1) A laboratory column experiment in which the fiber optic cable was buried in two layers of soils with different hydrogeologic properties. By using aFO-DTS, I evaluate the spatial resolution of soil moisture in the column and at the interface between the two layers of soil using the created protocol. (2) I apply my new aFO-DTS method to a constructed test waste-rock pile at the Lac Tio mine in eastern Quebec. The test pile is using a new capillary barrier cover design. By using aFO-DTS, I assess the temporal distribution of soil moisture at different depths within the pile (3). I test uncertainties and common assumptions used by aFO-DTS methods using a numerical model. To date, there has been very little analysis of the potential errors related to subsurface heterogeneity and method calibration. The rate and period of recharge are found to be among the largest potential sources of error and require careful calibration when using the aFO-DTS method"--

Author: Mauro Cappelli
Publisher: Woodhead Publishing
ISBN: 0081028377
Category : Technology & Engineering
Languages : en
Pages : 1114

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Instrumentation and Control Systems for Nuclear Power Plants provides the latest innovative research onthe design of effective modern I&C systems for both existing and newly commissioned plants, along withinformation on system implementation. Dr. Cappelli and his team of expert contributors cover fundamentals,explore the most advanced research in control systems technology, and tackle topics such as the human–machine interface, control room redesign, and control modeling. The inclusion of codes and standards,inspection procedures, and regulatory issues ensure that the reader can confidently design their own I&Csystems and integrate them into existing nuclear sites and projects. - Covers various viewpoints, including theory, modeling, design and applications of I&C systems - Includes codes and standards, inspection procedures and regulatory issues - Combines engineering and physics aspects in one thorough resource, presenting human factors, modeling and HMI together for the first time - Instrumentation and Control Systems for Nuclear Power Plants highlights the key role nuclear energy plays in the transition to a lower-carbon energy mix

Author: United States. Department of Energy
Publisher:
ISBN:
Category : Environmental monitoring
Languages : en
Pages : 180

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Author: Lucas Matthew Williamson
Publisher:
ISBN:
Category : Electronic books
Languages : en
Pages : 342

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There currently exists a gap in the field scale measurement of many soil properties. Particularly, efficient measurement of soil moisture over the field scale at depths below the top few centimeters of the soil column has proven elusive. Distributed temperature sensing (DTS) allows for the nearly continuous measurement of temperature over both a spatial and temporal scale by use of standard fiber optic cables. Measurement of temperature progression throughout a soil column can lead to estimates of bulk soil thermal properties. Theoretically, these estimated thermal properties used in conjunction with determined soil characteristics can then provide soil moisture estimates. At an experimental field site in Smith Valley, three fiber optic cables were installed into the shallow subsurface in a vertical profile at depths of 5, 10, and 15 centimeters. Cables were placed within plots of various crop types and varying irrigation schedules. The effect of both surface crop type and irrigation on subsurface soil temperature is analyzed and presented. Through inversion of the conduction equation, spatial and temporal results of thermal diffusivity across the field are assessed. Thermal response of the soil changes in accordance with wetting due to irrigation, as well as subsequent drying up of the soil.In terms of soil moisture, it continues to be difficult to accurately provide quantitative estimates, although drier soils provide much better estimates than do wet soils. Soil moisture estimates were in general agreement with observed values, but prior knowledge of the general wetness of the soil is necessary to improve the estimate. In a non-irrigated plot of tef ( eragrostis tef ), observed volumetric moisture values from the top 5 centimeters of soil ranged from 0.02 m3 /m3 to 0.18 m3 /m3 , while the estimated soil moisture contents integrated over a depth of 5 to 15 centimeters stayed fairly consistent around 0.12 m3 /m3 throughout the 25-day period. The effects of irrigation and cloudy conditions were clearly discernible, as were the relative differences between those plots receiving significant irrigation and those that remained drier throughout the study. The use of DTS in such an application can provide highly detailed pictures of temporally changing soil temperature, but progression to soil moisture estimation still remains challenging due to the non-uniqueness of the relation between soil thermal diffusivity and soil moisture content.

Author: Masoud Ghandehari
Publisher: Springer
ISBN: 3319707159
Category : Technology & Engineering
Languages : en
Pages : 256

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This book is an introduction to techniques and applications of optical methods for materials Characterization in civil and environmental engineering. Emphasizing chemical sensing and diagnostics, it is written for students and researchers studying the physical and chemical processes in manmade or natural materials. Optical Phenomenology and Applications - Health Monitoring for Infrastructure Materials and the Environment, describes the utility of optical-sensing technologies in applications that include monitoring of transport processes and reaction chemistries in materials of the infrastructure and the subsurface environment. Many of the applications reviewed will address long standing issues in infrastructure health monitoring such as the alkali silica reaction, the role of pH in materials degradation, and the remote and inset characterization of the subsurface environment. The remarkable growth in photonics has contributed immensely to transforming bench-top optical instruments to compact field deployable systems. This has also contributed to optical sensors for environmental sensing and infrastructure health monitoring. Application of optical waveguides and full field imaging for civil and environmental engineering application is introduced and chemical and physical recognition strategies are presented; this is followed by range of filed deployable applications. Emphasizing system robustness, and long-term durability, examples covered include in-situ monitoring of transport phenomena, imaging degradation chemistries, and remote sensing of the subsurface ground water.

Author: Javier Alvarez-Benedi
Publisher: CRC Press
ISBN: 1420032089
Category : Technology & Engineering
Languages : en
Pages : 816

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Book Description
The practitioner or researcher often faces complex alternatives when selecting a method to characterize properties governing a soil process. After years of research and development, environmental and agricultural professionals now have an array of methods for characterizing soil processes. Well-established methods, however, may not be suitable for