We developed a prototype geophysical system that currently has a dynamic range of 126dB. We also calculate the full potential of our design to achieve a dynamic range of greater than 160dB, which is orders of magnitude higher than what is currently offered by state of the art technology in geophysical instrumentation. We have been successful in reducing measurement errors that are common limiting factors in achieving high measurement sensitivity in practice. We reduced the measurement error caused by mechanical deformations of the measurement apparatus from 70PPM to less than 1PPM. As a result of developing a novel measurement method for using a rotating antenna array and digital nulling, we achieved a level of temporal drift of less than 1PPM over a 50 minute time period, which is a significant improvement compared to the drift of greater than 100PPM for the state of the art geophysical instrumentation. We also used a method of simultaneous calibration of the secondary fields in order to correct the measured data for the long-term gain variations in the system response. As a result, we reduced the percentage error in the RE and IM components of the target response measured over a 105-minute period of time from 5% and 80% to 0.5% and 2%, respectively. We have gained a substantial reduction of the measurement errors caused by the background response of the earth by using the antenna array in a vertical orientation relative to the earth's surface. We demonstrated that our measurement method increases survey efficiency because of a more informative set of data. We tested our prototype system with a section of steel pipe, which is a standard target used to determine the sensitivity of commercial metal detectors. The measurement results showed that our current system will detect this particular target at a 2.0m depth below the earth's surface, which is 0.5m better than the 1.5m detection depth achieved by the EM61-MK2. When the full potential of our design is realized, we estimate the projected depth of detection to increase to 9m, which is six times greater than the detection depth achieved by the EM61-MK2.

No description available.

No description available.

No description available.

This study aimed to gain an understanding of changing active layer dynamics in the High Arctic, specifically in terms of understanding the spatial distribution of mudboils to identify climatic and landscape controls, and active layer processes driving their formation. Systematic mapping of mudboils and sediment and water sampling was undertaken at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut in 2012 and 2013. Based on borehole stratigraphic profiles taken at CBAWO, three primary soil units were determined: mudboils at surface; overburden (soil) material; and a grey, fine-grained layer at approximately 80cm depth. These soil classes were used for comparison to gain an understanding of the properties and origins of the mudboil materials. Results indicate that these features only occur late in the melt season during exceptionally warm years (2007, 2011, and 2012) and in some cases closely follow major rainfall events. High-resolution satellite imagery was analyzed to determine landscape controls over mudboil formation. Notably, mudboils were significantly associated with bare soil and polar semi-desert vegetation settings, corresponding to increased active layer depth and rate of thaw when compared to more vegetated areas. Further, localized occurrence of mudboils appears to be related to differential soil moisture retention and spatially heterogeneous soil water pressurization due to thaw into the ice-rich transient layer in warm years. We hypothesize that the locally drier locations develop soil ped structures that contribute to diapir development and mud ejection when seasonal melt and hydraulic conditions pressurize soil water. Geotechnical and geochemical analysis of soil samples indicates that mudboils at surface do not significantly differ in terms of composition and physical properties from the undisturbed overburden material. This is consistent with a fine-grained slurry likely being generated in situ from a parent bed and subsequently ejected to surface. This research provides insights into the processes and landscape controls over mudboil formation to aid in understanding localized soil water response to deep summer thaw, with implications for surface water quality and predictions and potential mitigation of permafrost-related degradation and disturbance. / Thesis (Master, Geography) -- Queen's University, 2014-05-22 13:56:49.078

No description available.

A numerical model was utilized to assess the effects of elevated temperature on the application of in situ chemical oxidation (ISCO) and enhanced in situ bioremediation (EISB) for the subsurface remediation of trichloroethene (TCE) and tetrachloroethene (PCE). Temperature adjustment of the contaminant physicochemical properties as well as the chemical/biological reactions associated with ISCO and EISB were accounted for in the model domain. ISCO reaction rates were estimated using Arrhenius principles; microbial growth rates for EISB were estimated using non-linear fits to published literature data. The results from this study showed that temperature did provide remedial benefits to ISCO and EISB treatment during the short-term timeframe of oxidant/substrate injection. During these time periods, heated ISCO and EISB treatment exhibited greater DNAPL mass removal and mass flux reduction compared to heated abiotic dissolution. In the long term, after oxidant/substrate injection was terminated, the treatment enhancements achieved by ISCO and EISB were negated. Permeability (k) reduction due to rind formation (ISCO) and bioclogging (EISB) inhibited DNAPL dissolution and contributed to greater dissolution tailing effects. Tailing effects caused by ISCO were more severe compared to EISB since rind formation contributed to permanent k reduction; partial k recovery was observed in the EISB scenarios due to biomass decay. Even though higher temperatures were beneficial to ISCO and EISB during the short-term oxidant/substrate injection period, treatment efficacy was ultimately controlled by the detrimental by-products (rind from ISCO and biomass from EISB) formed as a result of the associative chemical/biological reactions. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-02-10 18:59:23.177

Water balance calculations were conducted for data obtained from a soil moisture characteristic to demonstrate the effect of different subsurface drain depths on the extent of droughtiness of a sandy soil. / Laboratory experiments were conducted on samples of sandy soils of the St. Lawrence lowlands to determine pertinent physical and soil-water properties. These properties were used, together with published crop data, to determine the effect of different subsurface drain depths on the quantity of available water in the soils studied. / Empirical relationships were derived among some of the properties measured, with the objective of enabling future drainage planners to make preliminary assessments of the likelihood of the occurrence of excessive drainage in a particular soil. / Based on information gained from this study, subsurface drainage-problem cases, representing conditions similar to those existing in the fields studied, were analysed and designs or design improvements were suggested for minimising the problem exemplified in each case.

Thesis (M.S. - Mining and Geological Engineering)--University of Arizona. / Includes bibliographical references (leaves 149-150).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 102-105). Also available via the Internet.