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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.
111

Using Network Models to Predict Steelhead Abundance, Middle Fork John Day, OR

Blanchard, Monica R. 01 May 2015 (has links)
In the management of threatened and endangered species, informed population estimates are essential to gage whether or not recovery goals are being met. In the case of Pacific salmonids, this evaluation often involves sampling a small subset of the population and scaling up to estimate larger distinct populations segments. This is made complicated by the fact that fish populations are not evenly distributed along riverscapes but respond to physical and biological stream properties at varying spatial extents. We used rapid assessment survey methods and the River Styles classification to explore fish-habitat relationships at a continuous network scale. Semi-continuous surveys were conducted across nine streams in the upper Middle Fork John Day River watershed and increased the number of sites surveyed eight-fold over other monitoring methods within the watershed. Using this increased sample size and continuous habitat metrics we improved watershed-wide steelhead (Oncorhynchus mykiss) abundance models. We first validated the distinctions among River Styles through a classification analysis using physical metrics measured at the rapid assessment sites. Overall classification accuracy, using a combination of reach and landscape scale metrics, was 88.3% and suggested that River Style classification was identifying variations in physical morphology within the watershed that was quantifiable at the reach scale. Leveraging the continuous River Styles classification of physical habitat and a continuous model of primary production improved the prediction of steelhead abundance across the network. Using random forest regressions, a model that included only habitat metrics resulted in R2 = 0.34, while using the continuous variables improved the model accuracy greatly to R2 = 0.65. Random forest allowed for further investigation into the predictor variables through the analysis of the partial dependence plots and identified a gross primary production threshold, below which production might be limiting steelhead populations. This method also identified the rarest River Style surveyed within the watershed, Confined-Valley Step Cascade, as the morphology that had the largest marginal effect on steelhead. The inherent physical properties and boundary conditions unique to each River Style has the potential to inform fish-habitat relationships across riverscapes and improve abundance estimates on a continuous spatial scale.
112

Development of Single-Molecule Mechanochemical Biosensors for Ultrasensitive and Multiplex Sensing of Analytes

Mandal, Shankar 30 April 2019 (has links)
No description available.
113

Mapping and Kinematic Structural Analysis of the Deep Creek Fault Zone, South Flank of the Uinta Mountains, Near Vernal, Utah

Haddox, David A. 11 May 2005 (has links) (PDF)
The geology along the southern flank of the Uinta Mountains, located north of Vernal, Utah, has been mapped at the 7.5' scale within two quadrangles: the Dry Fork and Steinaker Reservoir Quadrangles. Ambiguities dealing with stratigraphy, structural geology, and geohazards are currently being addressed as a result of this and other mapping projects in the vicinity. The geologic units in the area range in age from Mississippian to Late Cretaceous and include Uinta-sourced Tertiary units. Brief unit descriptions are provided for each of the units exposed in the map area. The main structural influence on the rocks within the area is that of the Uinta Uplift and its southern bounding fault, the Uinta Basin Boundary thrust. Locally, the Deep Creek fault zone overprints and dissects the southernmost flank of the broad Uinta Anticline. Other smaller structurally complex areas and folds exist east of the Deep Creek fault zone. The Deep Creek fault zone is made up of a series of NW-SE trending faults, likely related to the South Flank fault zone. Many authors have inferred dip-slip movement along the South Flank fault zone, but have not supported these claims using kinematic data. Detailed mapping and kinematic data collected within the study area has produced a better understanding of the deformation history along the fault zones in question. The faults within the Deep Creek fault zone have steep, linear traces upon which both vertical dip-slip and very nearly strike-slip (left-lateral oblique-slip, mainly) movement has occurred. The faults of the Deep Creek fault zone are likely Paleocene in age. The data suggest a bimodal history of deformation which the principal stress field does not seem to be influenced by typical east-northeast-west-southwest Laramide orogenic far-field stresses. The creation and early history of these faults may have been due to localized stress fields related to activity of the underlying Uinta Basin Boundary thrust, or a later period of uplift, a possible accommodation zone between the western and eastern domes of the Uinta Mountain Range, a transfer zone between the Uinta Basin Boundary thrust and the Asphalt Ridge fault, or a combination of these.
114

Wafer-Level Vacuum-Encapsulated Ultra-Low Voltage Tuning Fork MEMS Resonator

Huan, Junjun 24 May 2017 (has links)
No description available.
115

Updating the Lower East Fork Watershed Management Plan

Rooks, Alyssa D.L. 31 July 2017 (has links)
No description available.
116

Restoration of the endangered Cumberland elktoe (Alasmidonta atropurpurea) and Cumberland bean (Villosa trabalis) (Bivalvia: Unionidae) in the Big South Fork National River and Recreation Area, Tennessee and Kentucky

Guyot, Jennifer Ann 04 April 2006 (has links)
The Big South Fork National River and Recreation Area (NRRA), located in Tennessee and Kentucky, has prepared a management plan to include restoration of its mussel fauna to historic levels. Restoration activities include propagation of juvenile mussels and relocation of adults to suitable sites in the Big South Fork of the Cumberland River (BSF) and its tributaries. This study was conducted to identify host fish for Cumberland elktoe (Alasmidonta atropurpurea) and Cumberland bean (Villosa trabalis), to determine suitable juvenile culture conditions for Epioblasma brevidens and V. trabalis, and to locate sites important to future mussel restoration efforts in the NRRA. Host fish identifications and propagation techniques were determined for two of the endangered species in the NRRA, Cumberland elktoe (Alasmidonta atropurpurea) and Cumberland bean (Villosa trabalis). Of seven host species tested, banded sculpin (Cottus carolinae) was the most suitable host fish for propagation of A. atropurpurea. Of five host species tested, fantail darters (Etheostoma flabellare) were the most suitable host fish for propagation of V. trabalis. Culture techniques to raise juvenile mussels in captivity were evaluated, using newly metamorphosed juveniles of V. trabalis and E. brevidens in recirculating systems. No differences in juvenile growth or survival were detected among substrates used (fine sediment, coarse sand, and a mixture of the two). Recirculating system design seemed to affect juvenile growth and survival; however, variable condition of juveniles also seemed to affect results, making it difficult to determine effects from trial treatments. Finally, an assessment of potential sites in the NRRA for restoration activities was conducted using spatial analysis in a geographic information system (GIS) and several measures of conservation value. Mussel restoration sites were assessed for potential threats from adjacent land uses that may negatively affect mussels, including coal mines, oil and gas wells, transportation corridors, agriculture and urban development. Sites were also evaluated on their current conservation value to designate which sites are most important to long-term maintenance of mussel fauna. Several sites were identified that contain relatively few land-use threats, and are appropriate for mussel restoration activities, including Big Island, Station Camp Creek, and Parchcorn Creek sites on the mainstem BSF, as well as sites on Clear Fork and North White Oak Creek. Many of these sites also have high conservation values. Other sites had relatively high land-use threats that need to be addressed before restoration activities take place. Such sites include Leatherwood Ford, Rough Shoals Branch, Blue Heron, and Yamacraw on the mainstem BSF. The dominant threat to most sites came from transportation corridors, whereas some sites in southern and eastern portions of the watershed also were threatened by coal mines, and oil and gas wells. / Master of Science
117

Recovery status and chemosensory cues affecting reproduction of freshwater mussels in the North Fork Holston River downstream of Saltville, Virginia

Henley, William F. 18 September 2008 (has links)
The freshwater mussel fauna of the North Fork Holston River (NFHR) downstream of Saltville, VA declined from at least 24 species, as observed in 1918, to one species in 1974 due to mercury pollution. To determine the degree of recovery of mussels in the NFHR downstream of Saltville, and to provide recommendations for future mussel translocation sites, 19 sites were surveyed using a snorkeling catch-per-unit-effort (CPUE) method. At sites where investigator CPUE values (no./h) equaled or exceeded 5 mussels/h, a CPUE survey was conducted along transect lines. If investigator CPUE values equaled 10 mussels/h, a quadrat survey was conducted along the transects. Nine species of mussels were observed in the NFHR, and reproduction, as indicated by the presence of juveniles, was noted at 5 sites. Recovery of mussels was judged to be occurring downstream of NFHRM 56.4 based on species aggregations and recruitment. The number of mussels collected at sites, random CPUE (no./h), transect CPUE (no./h), and density (no./O.25m2) were generally inversely correlated to total Hg content, but not methyl mercury content, as measured in Corbicula fluminea from proximate sites. Random and transect CPUE (no./h) were found to be poor predictors of site densities (no./O.25m2) and popUlation estimates. Translocation recommendations for the NFHR downstream of Saltville, VA were made based on species aggregations, recruitment, and the distribution of total mercury. / Master of Science
118

Structural diagenetic attributes of the late Cretaceous Williams fork sandstones with implications for petrophysical interpretation and fracture prediction, Piceance Basin, Colorado

Ozkan, Aysen, 1974- 17 September 2010 (has links)
Diagenetic and structural aspects of tight gas sandstones must be addressed concurrently in order to fully understand low-permeability sandstones and to better predict their reservoir quality attributes that arise from a combination of pore-scale and fracture distribution characteristics. This dissertation focuses on aspects of rock evolution that are germane to concurrent structural and diagenetic evolution, such as loading and thermal history, rock mechanical property evolution, and fracture timing. I tested the hypothesis that the cement precipitation step, governed by thermal exposure and grain surface attributes, governs how sandstone attributes evolve using observations from the Late Cretaceous Williams Fork sandstones from the Piceance Basin, Colorado. My research shows that essential information for predicting and understanding fracture patterns in sandstone can be obtained by unraveling cement precipitation (diagenetic) history. Fractures depend on the mechanical properties existing during fracture growth. I show that key rock mechanical properties (subcritical crack index, Young's modulus and Poisson's ratio), petrophysical behavior, and reservoir quality depend in a systematic way on time-temperature history and the intrinsic grain surface attributes of these sandstones. I classified the Williams Fork lithofacies petrographically and correlated those with log responses to create a model that can be used to predict reservoir quality and diagenesis directly from well logs. I determined rock mechanical characteristics by measuring the subcritical crack index (SCI), a mechanical property that influences fracture distribution characteristics, and by examining log-derived bulk mechanical properties. To quantify the influence of quartz cementation on the SCI and to determine the range of SCI values for sandstone of given framework composition at different diagenetic stages, I measured SCI on Williams Fork core samples and their outcrop equivalents. Diagenetic modeling is applied to determine the sandstone characteristics during fracturing. / text
119

Fork Configuration Damper (FCDs) for Enhanced Dynamic Performance of High-rise Buildings

Montgomery, Michael S. 24 July 2013 (has links)
The dynamic behaviour of high-rise buildings has become a critical design consideration as buildings are built taller and more slender. Large wind vibrations cause an increase in the lateral wind loads, but more importantly, they can be perceived by building occupants creating levels of discomfort ranging from minor annoyance to severe motion sickness. The current techniques to address these issues include stiffening the lateral load resisting system, reducing the number of stories, or incorporating a vibration absorber at the top of the building. All of which have consequences on the overall project cost. The dynamic response of high-rise buildings is highly dependent on damping. Full-scale measurements of high-rise buildings have shown that the inherent damping decreases with height and recent in-situ measurements have shown that the majority of buildings over 250 meters have levels of damping less than 1% of critical. Studies have shown that small increases in the inherent damping can lead to vast improvement in dynamic response. A new damping system, the viscoelastic (VE) Fork Configuration Damper (FCD), has been developed at the University of Toronto to address these design challenges. The proposed FCDs are introduced in lieu of coupling beams in reinforced concrete (RC) coupled wall buildings and take advantage of the large shear deformations at these locations when the building is subjected to lateral loads. An experimental study was conducted on 5 small-scale VE dampers to characterize the VE material behaviour and 6 full-scale FCD samples in an RC coupled wall configuration (one designed for areas where low to moderate ductility is required and one with built-in ductile structural “fuse” for areas where high ductility is required). The VE material tests exhibited stable hysteretic behaviour under expected high-rise loading conditions and the full-scale tests validated the overall system performance based on the kinematic behaviour of coupled walls, wall anchorage and VE material behaviour. Analytical models were developed that capture the VE material behaviour and the FCD system performance well. An 85-storey high-rise building was studied analytically to validate the design approach and to highlight the improvements in building response resulting from the addition of FCDs.
120

Fork Configuration Damper (FCDs) for Enhanced Dynamic Performance of High-rise Buildings

Montgomery, Michael S. 24 July 2013 (has links)
The dynamic behaviour of high-rise buildings has become a critical design consideration as buildings are built taller and more slender. Large wind vibrations cause an increase in the lateral wind loads, but more importantly, they can be perceived by building occupants creating levels of discomfort ranging from minor annoyance to severe motion sickness. The current techniques to address these issues include stiffening the lateral load resisting system, reducing the number of stories, or incorporating a vibration absorber at the top of the building. All of which have consequences on the overall project cost. The dynamic response of high-rise buildings is highly dependent on damping. Full-scale measurements of high-rise buildings have shown that the inherent damping decreases with height and recent in-situ measurements have shown that the majority of buildings over 250 meters have levels of damping less than 1% of critical. Studies have shown that small increases in the inherent damping can lead to vast improvement in dynamic response. A new damping system, the viscoelastic (VE) Fork Configuration Damper (FCD), has been developed at the University of Toronto to address these design challenges. The proposed FCDs are introduced in lieu of coupling beams in reinforced concrete (RC) coupled wall buildings and take advantage of the large shear deformations at these locations when the building is subjected to lateral loads. An experimental study was conducted on 5 small-scale VE dampers to characterize the VE material behaviour and 6 full-scale FCD samples in an RC coupled wall configuration (one designed for areas where low to moderate ductility is required and one with built-in ductile structural “fuse” for areas where high ductility is required). The VE material tests exhibited stable hysteretic behaviour under expected high-rise loading conditions and the full-scale tests validated the overall system performance based on the kinematic behaviour of coupled walls, wall anchorage and VE material behaviour. Analytical models were developed that capture the VE material behaviour and the FCD system performance well. An 85-storey high-rise building was studied analytically to validate the design approach and to highlight the improvements in building response resulting from the addition of FCDs.

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