An application of ground penetrating radar to peat stratigraphy of Ellice Swamp, southwestern Ontario

1990 ◽  
Vol 27 (7) ◽  
pp. 932-938 ◽  
Author(s):  
Barry G. Warner ◽  
David C. Nobes ◽  
Brian D. Theimer

Ground penetrating radar (GPR) has been applied to the mapping of stratigraphy and peat thickness of a large bog in southwestern Ontario. The GPR survey was undertaken in conjunction with a conventional coring survey and measurement of peat physical properties. The results indicate that GPR responds to peat moisture content and bulk density, which vary with stratigraphic changes. In particular, the acrotelm–catotelm boundary and the basal clay are GPR reflectors. The presence of gyttja above the clay is indicated by complex basal reflections. Ground penetrating radar is a viable alternative to an intensive coring survey for evaluating peat depth and extent.

2016 ◽  
Vol 824 ◽  
pp. 100-107 ◽  
Author(s):  
Alena Struhárová

Bulk density and moisture content are factors that significantly affect the physical properties of autoclaved aerated concrete (AAC) including thermal conductivity and other thermo-technical characteristics. This article shows the results of measurements of compressive strength, capillary absorption, water absorption and porosity of AAC (ash on fluidized fly ash) at different bulk density and also the results of thermal conductivity of AAC at different bulk density and variable moisture content of the material. The thermo-technical properties were measured using the Isomet 2104, a portable measuring device. Acquired results demonstrate dependence of physical properties including thermal conductivity of AAC on bulk density and moisture content. The reliability and accuracy of the method of measuring was also shown.


2013 ◽  
Vol 122 (4) ◽  
pp. 250-255
Author(s):  
A. Benter ◽  
W. Moore ◽  
M. Antolovich

2018 ◽  
Vol 23 (4) ◽  
pp. 489-496
Author(s):  
J. David Redman ◽  
A. Peter Annan ◽  
Nectaria Diamanti

Bulk electrical properties of media are important inherently for ground penetrating radar (GPR) applications and for providing a means to determine indirectly other physical properties such as moisture content. We have developed a reflector whose reflectivity can be controlled electronically. This variable reflector controlled by a GPR provides an effective method to measure bulk electrical properties of media. For sample measurements, the GPR is placed on one side of a sample and the variable reflector on the opposite side. GPR trace data are then acquired with the reflector in an on-state and in the off-state. By differencing these measurements, we improve the ability to detect the specific reflection event from the variable reflector. This process removes both the direct wave and clutter from the trace data, improving the quality of the refection event and our ability to accurately pick its arrival time and amplitude. We describe the variable reflector, a prototype instrument based on the reflector and numerical modeling performed to understand its response. We also show the results of testing applications to the measurement of wood chip moisture content and monitoring of the electrical properties of concrete during the curing process.


2019 ◽  
Vol 11 (2) ◽  
pp. 141 ◽  
Author(s):  
Ikechukwu Ukaegbu ◽  
Kelum Gamage ◽  
Michael Aspinall

This study reports on the combination of data from a ground penetrating radar (GPR) and a gamma ray detector for nonintrusive depth estimation of buried radioactive sources. The use of the GPR was to enable the estimation of the material density required for the calculation of the depth of the source from the radiation data. Four different models for bulk density estimation were analysed using three materials, namely: sand, gravel and soil. The results showed that the GPR was able to estimate the bulk density of the three materials with an average error of 4.5%. The density estimates were then used together with gamma ray measurements to successfully estimate the depth of a 658 kBq ceasium-137 radioactive source buried in each of the three materials investigated. However, a linear correction factor needs to be applied to the depth estimates due to the deviation of the estimated depth from the measured depth as the depth increases. This new application of GPR will further extend the possible fields of application of this ubiquitous geophysical tool.


2016 ◽  
Author(s):  
Hamza Reci ◽  
Tien Chinh Maï ◽  
Zoubir Mehdi Sbartaï ◽  
Lara Pajewski ◽  
Emanuela Kiri

Abstract. This paper presents the results of a series of laboratory measurements carried out to study how the Ground Penetrating Radar (GPR) signal is affected by moisture variation in wood material. The effects of the wood fiber direction, with respect to the polarisation of the electromagnetic field, are investigated. The relative permittivity of wood and the amplitude of the electric field received by the radar are measured for different humidity levels, by using the direct-wave method in Wide Angle Radar Reflection configuration, where one GPR antenna is moved while the other is kept in a fixed position. The received signal is recorded for different separations between transmitting and receiving antennas. Direct waves are compared to reflected waves: it is observed that they show a different behaviour when the moisture content varies, due to their different propagation paths.


2011 ◽  
Vol 6 (No. 2) ◽  
pp. 73-82 ◽  
Author(s):  
S.E. Obalum ◽  
J.C. Nwite ◽  
J. Oppong ◽  
C.A. Igwe ◽  
T. Wakatsuki

One peculiar feature of the inland valleys abundant in West Africa is their site-specific hydrology, underlain mainly by the prevailing landforms and topography. Development and management of these land resources under the increasingly popular sawah (a system of bunded, puddled and levelled rice field with facilities for irrigation and drainage) technology is a promising opportunity for enhancing rice (Oryza sativa L.) production in the region. Information on the variations in selected soil physical properties as influenced by the prevailing landforms may serve as a useful guide in site selection. This is of practical importance since majority of the inland valleys are potentially unsuitable for sawah development and most farmers in the region are of low technical level. Three landforms (river levee, elevated area and depressed area) were identified within a sawah field located in an inland valley at Ahafo Ano South District of Ghana. Each of these landforms was topsoil-sampled along on identified gradient (top, mid and bottom slope positions). Parameters determined included particle size distribution, bulk density, total porosity and field moisture content. The soil is predominantly clayey. There were no variations in the particle size distribution among the slope positions in the river levee. Overall, the river levee had lower silt content than the elevated and the depressed landforms. The bulk density, total porosity, and gravimetric moisture content indicated relative improvements only in the depressed area in the order, bottom &gt; mid &gt; top slope. Irrespective of slope position, the three landforms differed in these parameters in the order, depressed &gt; river levee &gt; elevated. The sand fraction impacted negatively on the silt fraction and bulk density of the soil, both of which controlled the soil moisture status. Despite the fairly low silt content of the soil, the silt fraction strongly influenced the gravimetric moisture content (R<sup>2</sup> = 0.80). So too did the soil bulk density on the gravimetric moisture content (R<sup>2</sup> = 0.90). It is concluded that: (1) since the landforms more prominently influenced the measured parameters than the slope positions, the former should take pre-eminence over the latter in soil suitability judgment; (2) with respect to moisture retention, variations in silt fraction and bulk density of this and other clayey inland-valley soils should be used as guide in site selection for sawah development.


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