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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

Comparison of Urban Tree Canopy Classification With High Resolution Satellite Imagery and Three Dimensional Data Derived From LIDAR and Stereoscopic Sensors

Baller, Matthew Lee 22 August 2008 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Despite growing recognition as a significant natural resource, methods for accurately estimating urban tree canopy cover extent and change over time are not well-established. This study evaluates new methods and data sources for mapping urban tree canopy cover, assessing the potential for increased accuracy by integrating high-resolution satellite imagery and 3D imagery derived from LIDAR and stereoscopic sensors. The results of urban tree canopy classifications derived from imagery, 3D data, and vegetation index data are compared across multiple urban land use types in the City of Indianapolis, Indiana. Results indicate that incorporation of 3D data and vegetation index data with high resolution satellite imagery does not significantly improve overall classification accuracy. Overall classification accuracies range from 88.34% to 89.66%, with resulting overall Kappa statistics ranging from 75.08% to 78.03%, respectively. Statistically significant differences in accuracy occurred only when high resolution satellite imagery was not included in the classification treatment and only the vegetation index data or 3D data were evaluated. Overall classification accuracy for these treatment methods were 78.33% for both treatments, with resulting overall Kappa statistics of 51.36% and 52.59%.
162

Three-Dimensional Target Modeling with Synthetic Aperture Radar

Hupton, John R 01 January 2009 (has links) (PDF)
Conventional Synthetic Aperture Radar (SAR) offers high-resolution imaging of a target region in the range and cross-range dimensions along the ground plane. Little or no data is available in the range-altitude dimension, however, and target functions and models are limited to two-dimensional images. This thesis first investigates some existing methods for the computation of target reflectivity data in the deficient elevation domain, and a new method is then proposed for three-dimensional (3-D) SAR target feature extraction. Simulations are implemented to test the decoupled least-squares technique for high-resolution spectral estimation of target reflectivity, and the accuracy of the technique is assessed. The technique is shown to be sufficiently accurate at resolving targets in the third axis, but is limited in practicality due to restrictive requirements on the input data. An attempt is then made to overcome some of the practical limitations inherent in the current 3-D SAR methods by proposing a new technique based on the direct extraction of 3-D target features from arbitrary SAR image inputs. The radar shadow present in SAR images of MSTAR vehicle targets is extracted and used in conjunction with the radar beam depression angle to compute physical target heights along the range axis. Multiple inputs of elevation data are then merged to forge rough 3-D target models. The project is a continuation of prior SAR research at Cal Poly under Dr. John Saghri with the sponsorship of Raytheon Space & Airborne Systems.
163

THREE-DIMENSIONAL ANALYSIS OF CONSTITUENT REDISTRIBUTION AND SWELLING IN A NEUTRON IRRADIATED U- 10 WT.% ZR FUEL USING FIB-SEM SERIAL SECTIONING

Nicole Rodriguez Perez (15354319) 27 April 2023 (has links)
<p>  </p> <p>Transition to a sustainable power grid entails the use of all net-zero carbon emission technology that is currently available. Liquid metal-cooled fast nuclear reactors (LMFRs) are technologies capable of competitively providing power while attaining sustainability and reliability. Uranium-zirconium metallic alloys have been proposed as LMFRs fuels based on the performance of the fuel in experimental scale reactors, achieving up to 20 at.% burn-up. The following phenomena affects the irradiation performance of U-Zr fuels: constituent redistribution, swelling, fuel-cladding mechanical interaction (FCMI), and fuel-cladding chemical interaction (FCCI). Further understanding of these phenomena, and development of predictive models requires data collection of variables such as composition, morphology of the redistribution regions, porosity distribution, porosity morphology, fission gas release, and the relation between local composition and porosity evolution. </p> <p>To achieve this, focused ion beam-scanning electron microscopy (FIB-SEM) serial sectioning was applied to specimens from the different compositional regions developed during constituent redistribution of a U-10 wt.% Zr fuel neutron irradiated to 5.7 at.% burn-up. High-resolution backscattered electron (BSE) micrographs, and energy dispersive spectroscopy (EDS) spectra were obtained for several sections of each specimen. Each section was analyzed to identify the microstructural and compositional evolution in the specimen volume. Three-dimensional porosity and phase volume distribution was obtained using image processing and three-dimensional object classification. The study revealed local segregation of phases within each of the regions, porosity distribution dependency on temperature and local composition, preferential porosity nucleation sites, porosity evolution trends, interconnectivity, possible sinks/nucleation sites for porosity and precipitates, as well as possible mechanisms for fission gas release.</p>
164

Facies Architecture and Provenance of the Highly Progradational, Fluvial Dominated Deltaic Depositional System of the Cretaceous Nanushuk Formation on the North Slope of Alaska

Naone, Sarah N. 07 December 2022 (has links)
The Cretaceous Nanushuk Formation of northern Alaska records extremely rapid shoreline progradation across the Colville Basin during the Albian-Cenomanian epochs. Additionally, it records a period of tectonic realignment in the region, as the main sediment source began to transition from the Chukotkan orogeny to the west to a more local sediment source of the proximal Brooks Range to the south. Through detailed outcrop characterization and 3-D modeling of three exposed outcrops along the axial trend of the Colville Basin on the North Slope and the Upper section of the Nanushuk, this study clarifies the relative timing of the early Brookian orogenic uplift. Outcrop characterization also allows for a detailed description of spatial and temporal distribution of deltaic facies associations within the Nanushuk Formation. Previously these outcrops were hypothesized to represent dominantly shoreface depositional processes, but field studies indicate the Nanushuk Formation has a complex facies architecture consistent with deltaic environments. This work has important significance for geometry predictions for hydrocarbon exploration and development targeting the Nanushuk sands as a reservoir unit. This new interpretation of both dominant sedimentary process and provenance has implications for 1) reservoir architecture and connectivity, and 2) textural and compositional maturity of Nanushuk sandstones, an emerging hydrocarbon play along the North Slope of Alaska. A detailed mineralogical analysis of 50 samples, coming from the three key outcrops and two additional outcrops from previous studies, using TESCAN Integrated Mineral Analyzer (TIMA), an automated system that utilizes Scanning Electron Microscopy (SEM), shows increased amounts of chromite and biotite associated with key outcrops proximal to the Brooks Range. Chromite mass weight percent ranges from 0.00 % to 0.15 % across five outcrops, with Tuktu Bluff, which is proximal to the Brookian orogenic front having weight percentages that range from 0.01 % to 0.15 % with an average of 0.06 %, in contrast to the other outcrops, which range from 0.00 % to 0.03 % with an average of 0.01 %. In contrast, non-diagnostic elements such as quartz do not show meaningful variance, ranging from 42.66 % to 93.78 % across all outcrops, with proximal outcrop showing an average of 60.64 % while the rest of the outcrops have an average of 64.36 %. Substantial localized enrichment in both chromite and biotite found within outcrops of the Nanushuk Formation at the Tuktu Bluff locality support subaerial exposure of the Brooks Range within the Albian-Cenomanian epochs. The non-uniform distribution of these minerals on both a strike and dip direction show that uplift was non-uniform and suggest specific point sources dominated Brookian input. A better understanding of these patterns will help to focus exploration in areas of best potential reservoir quality. Measured sections and 3-d models were created to better understand the depositional architecture and how the deltaic influence in this highly progradational system affects the reservoir geometries. In all three outcrops of interest along the axial trend and higher up in the Nanushuk section, we observed current ripples, lensoidal geometries, low angle trough cross bedding, scoured bases, and wood chunks and pebble lags at channel basses, all of which, are consistent with fluvial dominated deltas. Deltaic deposition complicates predicting the geometry of the reservoir away from outcrop control with lateral avulsions of the delta system and laterally changing distributary channels. At Ninuluk, Kanayut, and Rooftop Ridge, distributary and interdistributary channels comprise approximately 19.5 %, 23.5 % and 20.36 % of the outcrop, respectively. Overall, net to gross sand ratios of 38.69 %, 66.54 % and 55.47 % were calculates at Ninuluk, Kanayut, and Rooftop Ridge, respectively. If assuming the sands in the net to gross are the reservoir rock, then approximately half of the reservoir rocks at each outcrop are in distributary channel settings which adds to the complexity of facies prediction away from the control outcrops.
165

Surveying, modelling and visualisation of geological structures in the Tunbergettunnel

Surur, Anwar January 2008 (has links)
The 3-d visualisation of a section of the Tunberget tunnel and important fracture zones was accomplished by combination of the topographic surface, measurements at the surface of fracture planes together with surfaces of dolerite dykes, results from magnetic modeling of dolerite dykes and tunnel mapping data. The topographic surface was represented as elevation contours with 1 m equidistance. The fracture and dolerite surfaces were measured geodetically in the field from a net of 20 total station locations. Each surface was measured at 3 points to determine its strike and dip. Totally 44 strike and dip estimates were obtained. The extent at depth of the dolerite dykes was also estimated based on magnetic measurements along 3 profiles. The location of the dykes was also known from geological tunnel mapping. ArcGIS and RockWorks have been used to process the data and to generate a 3-d visualization of the geometrical relation between targeted geological structures, the dolerite dykes and the tunnel. The area is of interest to be studied in more detail as the fracture zones and the parallel dolerite dykes connect the tunnel with a large wetland complex. / QC 20100707
166

The Effects of Stereoscopic Technologies on Subjects’ Ability to Perform a LEGO Block Construction Task

Lauthers, Chad M. 27 March 2006 (has links)
No description available.
167

Further development of 3-D rotary-wing acoustic directivity using a spherical harmonic representation

Mobley, Frank Spencer 11 May 2012 (has links)
No description available.
168

Comparative Morphology of the Glossopodia of Three North American Isoetes Ligules

Shaw, Shane William 02 November 2004 (has links)
No description available.
169

Classification of Man-made Urban Structures from Lidar Point Clouds with Applications to Extrusion-based 3-D City Models

Thomas, Anita 19 May 2015 (has links)
No description available.
170

Fracture Properties of Thermoplastic Composites Manufactured Using Additive Manufacturing

Ravi Prame, Manush January 2017 (has links)
No description available.

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