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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

A GEOPHYSICAL INVESTIGATION SEARCHING FOR ARCHAEOLOGICAL FEATURES AT SUNWATCH INDIAN VILLAGE

Torridi, Danielle 09 July 2012 (has links)
No description available.
162

Three Dimensional Analysis of a Proglacial Clastic Dyke Network Using Ground Penetrating Radar, Skeidararsandur, Iceland

Korte, David M. 22 November 2013 (has links)
No description available.
163

Finite difference time domain modeling of dispersion from heterogeneous ground properties in ground penetrating radar

Holt, Jennifer Jane 22 April 2004 (has links)
No description available.
164

Barrier evolution of Cape San Blas, Saint Joseph Peninsula, Florida from textural analysis, ground penetrating radar and organic matter isotope geochemistry

Ahmad, Shakeel 04 1900 (has links)
<p>St. Joseph peninsula is situated on the panhandle of Florida west coast in the northeastern Gulf of Mexico at N29°50‘ and W85°20‘ and is located at the west edge of the westernmost portion of the Apalachicola Barrier Island Complex (ABIC) on the Gulf of Mexico shoreline. Three vibra-cores were collected on Saint Joseph Bay side of Cape San Blas which is part of St. Joseph peninsula to determine its evolution in context of previous work by Rink and Lopez (2010). The study uses detailed textural analysis (PSD - Particle Size Distribution plots), multivariate statistics on the PSDs (Q-mode cluster analysis) and organic matter geochemistry (C/N and δ13C). In addition, Ground Penetrating Radar (GPR) profiles are used to provide broader stratigraphic context.</p> <p>The stratigraphic analysis found that CSB has an older nucleus of strandplain deposits dating to >12 Ka that were subsequently flooded and modified through Holocene sea-level rise at ≈ 2.2 Ka. Actual barrier formation began sometime between 2.2. Ka and 0.6 Ka which is the oldest beach ridge measured by Rink and Lopez (2010). Progradation of the barrier on the St Joseph Bay side began at least by 0.3 Ka and likely earlier. There is no evidence to indicate a higher than present sea-level in our core data and our data follows that of other sea-level studies using submerged offshore samples</p> / Master of Science (MSc)
165

Analysis and implementation of low fidelity radar-based remote sensing for unmanned aircraft systems

Duck, Matthew 13 May 2022 (has links)
Radar-based remote sensing is consistently growing, and new technologies and subsequent techniques for characterization are changing the feasibility of understanding the environment. The emergence of easily accessible unmanned aircraft system (UAS) has broadened the scope of possibilities for efficiently surveying the world. The continued development of low-cost sensing systems has greatly increased the accessibility to characterize physical phenomena. In this thesis, we explore the viability and implementation of using UAS as a means of radar-based remote sensing for ground penetrating radar (GPR) and polarimetric scatterometry. Additionally, in this thesis, we investigate the capabilities and implementations of low-cost microwave technologies for applications in radar-based remote sensing compared to higher fidelity and more expensive technologies of similar scope.
166

GROUND-PENETRATING RADAR IMAGES OF A DYE TRACER TEST WITHIN THE UNSATURATED ZONE AT THE SUSQUEHANNA-SHALE HILLS CZO

Pitman, Lacey January 2014 (has links)
Dye tracer and time-lapse ground-penetrating radar (GPR) were used to image preferential flow paths in the shallow, unsaturated zone on hillslopes in two adjacent watersheds within the Susquehanna-Shale Hills Critical Zone Observatory (CZO). At each site we injected about 50 L of water mixed with brilliant blue dye (4 g/L) into a trench cut perpendicular to the slope (~1.0 m long by ~0.20 m wide by ~0.20 m deep) to create a line of infiltration. GPR (800 MHz antennae with constant offset) was used to monitor the movement of the dye tracer downslope on a 1.0 m x 2.0 m grid with a 0.05 m line spacing. The site was then excavated and the stained pathways photographed to document the dye movement. We saw a considerable difference in the pattern of shallow preferential flow between the two sites despite similar soil characteristics and slope position. Both sites showed dye penetrating down to saprolite (~0.40 m); however, lateral flow migration between the two sites was different. At the Missed Grouse field site, the lateral migration was ~0.55 m as an evenly dispersed plume, but at distance of 0.70 m a finger of dye was observed. At the Shale Hills field site, the total lateral flow was ~0.40 m, dye was barely visible until the excavation reached ~0.10 m, and there was more evidence of distinct fingering in the vertical direction. Based on laboratory and field experiments as well as processing of the radargrams, the following conclusions were drawn: 1) time-lapse GPR successfully delineated the extent of lateral flow, but the GPR resolution was insufficient to detect small fingers of dye; 2) there was not a distinct GPR reflection at the regolith-saprock boundary, but this interface could be estimated from the extent of signal attenuation; 3) the preliminary soil moisture conditions may explain differences in the extent of infiltration at the two sites; 4) rapid infiltration into the underlying saprock limited the extent of shallow lateral flow at both sites and can be seen using the mass balance calculation and the lateral extent of dye within the radargrams; and 5) variations in flow patterns were observed between sites with similar settings at Susquehanna-Shale Hills CZO. / Geology
167

Resonance-Based Techniques for Microwave Breast Cancer Applications

Hong, Sun 30 October 2012 (has links)
It is well known that a finite-size scatterer has a set of natural resonances, which are uniquely determined by the physical properties of the scatterer. This is also the case for a breast tumor which can be regarded as a dielectric scatterer. Since the scatterer is naturally "tuned" at the resonances, it is expected that an increased electromagnetic coupling would take place at the resonance frequencies compared to other frequencies. For a breast tumor, this would mean a higher power absorption, indicating a faster temperature increase resulting in more efficient hyperthermia. In this dissertation, an adaptive microwave concept is demonstrated for breast cancer applications. The general approach is to detect and identify the tumor-specific resonance, determine the electrical location of the tumor, and apply the focused microwave hyperthermia using the identified resonance and the electrical location. The natural resonances vary depending on the tumor size, shape, and breast tissue configuration. Therefore, an adaptive tuning of the microwave source to tumor-specific resonance frequencies could improve the overall efficiency of hyperthermia treatment by allowing for a faster and more effective heating to achieve a desired therapeutic temperature level. Applying the singularity expansion method (SEM), both the resonances and the electrical location can be obtained from the poles and residues, respectively. This SEM-based approach is computationally inexpensive and can easily be implemented as a combination processing into emerging UWB microwave systems. Alternatively, a relatively simple microwave system based on this concept can potentially be used in conjunction with existing mammography. / Ph. D.
168

Development of Data Analysis Algorithms for Interpretation of Ground Penetrating Radar Data

Lahouar, Samer 27 October 2003 (has links)
According to a 1999 Federal Highway Administration statistic, the U.S. has around 8.2 million lane-miles of roadways that need to be maintained and rehabilitated periodically. Therefore, in order to reduce rehabilitation costs, pavement engineers need to optimize the rehabilitation procedure, which is achieved by accurately knowing the existing pavement layer thicknesses and localization of subsurface defects. Currently, the majority of departments of transportation (DOTs) rely on coring as a means to estimate pavement thicknesses, instead of using other nondestructive techniques, such as Ground Penetrating Radar (GPR). The use of GPR as a nondestructive pavement assessment tool is limited mainly due to the difficulty of GPR data interpretation, which requires experienced operators. Therefore, GPR results are usually subjective and inaccurate. Moreover, GPR data interpretation is very time-consuming because of the huge amount of data collected during a survey and the lack of reliable GPR data-interpretation software. This research effort attempts to overcome these problems by developing new GPR data analysis techniques that allow thickness estimation and subsurface defect detection from GPR data without operator intervention. The data analysis techniques are based on an accurate modeling of the propagation of the GPR electromagnetic waves through the pavement dielectric materials while traveling from the GPR transmitter to the receiver. Image-processing techniques are also applied to detect layer boundaries and subsurface defects. The developed data analysis techniques were validated utilizing data collected from an experimental pavement system: the Virginia Smart Road. The layer thickness error achieved by the developed system was around 3%. The conditions needed to achieve reliable and accurate results from GPR testing were also established. / Ph. D.
169

D-Day: geophysical investigation of a World War II German site in Normandy, France

Gaffney, Christopher F., Adcock, J., Gater, J.A., Saunders, T. January 2004 (has links)
No / Although military sites have long been the subject of geophysical investigation, those associated with recent military campaigns are noticeably rare. In fact, although such techniques are increasingly used to identify the unwanted legacy of modern warfare, such as unexploded ordnances or mass burials, they have not been used to investigate the archaeology of such conflict. The survey here attempts to identify the archaeology of one military site (Puits d'Herode) that was part of Hitler's Atlantic Wall and to identify the key elements associated with its D-Day defences. Magnetic gradiometry, twin-probe resistance and ground-penetrating radar were used at this site and, as a result of the nature of the buried archaeology, the magnetic technique proved most valuable. Trenches and bunkers previously known from aerial photographs were located accurately and a track believed to relate to the post-D-Day advance of the Allied forces across Puits d'Herode was also identified. The use of geophysical data in the investigation of this site has provided a new avenue to examine previously difficult topics such as the quality of intelligence available at the time of the conflict and the level and accuracy of shelling; although these may seem unlikely targets for archaeological geophysics, they are important to military historians for whom eye witness accounts are becoming increasingly scarce.
170

Still searching for graves: an analytical strategy for interpreting geophysical data used in the search for "unmarked" graves

Gaffney, Christopher F., Harris, Chrys, Pope-Carter, F., Bonsall, James P.T., Fry, Robert J., Parkyn, Andrew K. January 2015 (has links)
No / Searching for and mapping the physical extent of unmarked graves using geophysical techniques has proven difficult in many cases. The success of individual geophysical techniques for detecting graves depends on a site-by-site basis. Significantly, detection of graves often results from measured contrasts that are linked to the background soils rather than the type of archaeological feature associated with the grave. It is evident that investigation of buried remains should be considered within a 3D space as the variation in burial environment can be extremely varied through the grave. Within this paper, we demonstrate the need for a multi-method survey strategy to investigate unmarked graves, as applied at a "planned" but unmarked pauper's cemetery. The outcome from this case study provides new insights into the strategy that is required at such sites. Perhaps the most significant conclusion is that unmarked graves are best understood in terms of characterization rather than identification. In this paper, we argue for a methodological approach that, while following the current trends to use multiple techniques, is fundamentally dependent on a structured approach to the analysis of the data. The ramifications of this case study illustrate the necessity of an integrated strategy to provide a more holistic understanding of unmarked graves that may help aid in management of these unseen but important aspects of our heritage. It is concluded that the search for graves is still a current debate and one that will be solved by methodological rather than technique-based arguments.

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