Global ETD Search

1	Quasi 3-Dimensional Electrical Resistivity Mapping of Air-filled Karst Conduits and Policy Implications Mccrackin, Charles W. 01 January 2012 (has links) This study assesses the capability and practical applications of quasi 3-Dimensional (3D) electrical resistivity surveying (ER) for mapping air-filled karst conduits. Vadose zone caves within the Brooksville Ridge of West Central Florida are relatively similar in architecture, with N-S elongation, and do not consist of an interconnected network of conduits. A high resolution quasi-3D ER survey was performed over two mapped cave systems on the Brooksville Ridge. The resultant survey verified the general effectiveness of quasi-3D ER in locating the two known near-surface cave features. Several other locations in the survey show similar or stronger resistivity anomalies trending in a N-S direction; these are interpreted to represent previously unknown voids. The quality of inversion results were tested by comparing results against the known void locations and by computing cross-over errors from surveys conducted at the same point with different orientations. Our results show that 3D inversions of multiple adjacent parallel profiles produces higher quality results (lower cross-over errors, better fit to cave locations) than 2D inversions. The data indicate that no single value of resistivity can be used as a reliable indicator of the presence of a void, presumably due to variable void size and the complexity in resistivities in the host rock. With sinkholes continuing to be of concern to residential and urban development in West Central Florida, the results of this research show the necessity of applying geophysical techniques in order to reduce the potential hazards posed by karst terrain. Brooksville Ridge Caves Electrical Resistivity Geophysics Karst Sinkholes American Studies Arts and Humanities Environmental Sciences Geology Geophysics and Seismology
2	An Analysis of Grain Corn Nutritional Supplements and Relative Maturity in Mississippi Whittenton, Joseph Bryan 04 May 2018 (has links) A review of available corn relative maturity groups in Mississippi shows a limited range of maturity groups in use. Research focusing on expanding the range of maturity groups was conducted in MS in 2015 and 2016. Along with expanded maturity groups, treatments of fertilizer (10-34-0), foliar zinc, and a plant hormone blend were studied to shorten the growing season. Four site years in MS were studied to determine optimal plant maturity group and treatment for length of season. The results showed decreased yield of 0.09-0.15 Mg ha-1 (1.5-2.3 bu ac-1) for each day of decreasing relative maturity in three of four site years. The addition of starter fertilizer increased vegetative growth stage, plant height V5 and V7, SPAD values at V5, and significantly decreases days to tassel and silking reproductive growth stages but did not affect yield. NDRE LREI SI ENDVI GNDVI NDVI plants per acre vegetation indices 30000 density leaf area index kernel column kernel row weight kernel tassel plant height brooksville verona starkville mississippi hybrid maturity foliar 2016 2015 corn yield spad spectral starter fertilizer 10-34-0 polyphosphate fertilizer zinc hormone ascend pioneer dekalb relative maturity

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Quasi 3-Dimensional Electrical Resistivity Mapping of Air-filled Karst Conduits and Policy Implications

An Analysis of Grain Corn Nutritional Supplements and Relative Maturity in Mississippi