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A Study Of The Effect Of Vibration On Railroad Bearing Temperature, Bertha Alicia Gonzalez

Theses and Dissertations - UTB/UTPA

An on-track collaborative field test and laboratory experiments were conducted in order to determine the relationship between abrupt rises in surface temperature of a railroad bearing and vibration signatures captured during the experiments. The collaborative field test was conducted in order to investigate the root cause for this abrupt temperature change known as bearing temperature trending. The research presented in this thesis will show that temperature trending is correlated to an increase in the magnitude of vibration within the bearing and the fundamental frequencies that are generated by the internal components of a rotating bearing assembly. Distinct vibration mechanisms are …

Assessing Linkages Among Landscape Characteristics, Stream Habitat, And Macroinvertebrate Communities In The Idaho Batholith Ecoregion, Andrew C. Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the composition of lotic communities and the landscape processes and habitat characteristics that shape them is one of the main challenges confronting stream ecologists. In order to better understand the linkages among landscape processes, stream habitat, and biological communities and to understand how accurately our measurements represent important factors influencing biological communities, it is important to test explicit hypotheses regarding these linkages. Increasing our understanding of aquatic communities in a hierarchical context and recognizing how well our measurements represent factors structuring aquatic communities will help managers better evaluate the influence of land management practices on aquatic ecosystems, direct conservation …

The Effectiveness Of Damage Arrestment Devices In Delaying Fastener-Hole Interaction Failures In Carbon Fiber Polyurethane Foam Composite Sandwich Panels Subjected To Static And Dynamic Loading Under Increased Temperatures, Dominic E. Surano

Master's Theses

A study was conducted to investigate simple, cost-effective manufacturing techniques to delay skin-core delamination, micro-buckling and bearing stress failures resulting from fastener-hole interactions. Composite sandwich panels, with and without damage arrestment devices (DADs), were subjected to monotonic compression at a rate of 5mm per second, and compression-compression fatigue at 50% yield at an amplitude of 65%, under temperatures of 75, 100, 125, 150, 175, and 200 °F.

The sandwiches tested were composed of two-layer cross-weave carbon fiber facesheets, a polyurethane foam core, and an epoxy film adhesive to join the two materials. The most successful method to delay the aforementioned …

Temperature And Variability Of Three Ionian Volcanoes, Daniel R. Allen

Theses and Dissertations

Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hotspots, Pillan, Wayland, and Loki. We found a maximum color temperature of 1130+/-289 K for Pillan and maximum color temperatures of 1297+/-289 K and 1387+/-287 K for Wayland and Loki, respectively. These temperatures are suggestive of basaltic lava. The temperatures with the best signal-to-noise ratios also suggested basaltic lava and were found to be 780+/-189 K, 1116+/-250 K, and 1017+/-177 K for Pillan, Wayland, and Loki, respectively. Pillan showed increased …

Factors Affecting Ammonia Volatilization From Broiler Litter, Dana Mcgee Miles

Theses and Dissertations

Loss of ammonia from broiler litter degrades air quality, decreases litter fertilizer value, and can have negative health consequences for birds and their caretakers. Rates of NH3 emission from broiler houses are complicated by interrelated management and environmental factors such as air temperature, humidity, house style, ventilation rate,bird age, litter conditions, litter characteristics, and cleanout schedule. Wide variations inemission rates necessitate further investigation of litter characteristics and abatement techniques. The research was designed to clarify the impact of moisture effects that are critical to emissions for poultry litter, in conjunction with bedding type and temperature. Experiments were conducted on litter …

Seed Coating, Seed Treatment, And Temperature Effects On Germination Of Five Seeded Bermudagrass Cultivars, John Morris Layton

Theses and Dissertations

The use of improved seeded bermudagrasses (SB) has increased. All new cultivars are marketed as coated seed. As germination of many of these new cultivars is less than ideal, questions arise as to the effect coatings have on germination. Five SB cultivars were selected for a series of germination studies. The first study compared coated and uncoated samples of the five cultivars for germination response to six temperature regimes. Overall, commercial seed coating did not affect SB germination. However, both temperature regime and cultivar were significant factors. In a second study, three seed treatments were investigated across three temperature regimes …

Irrigation Leak Detection: Using Flow Rate Sensors To Detect Breaks In An Irrigation System, Adam Openshaw, Kalvin Vu

Computer Engineering

This report details the exploration and invention of a mechanism that can detect breaks in an irrigation system. With the ultimate goal of conserving water, we have designed an inexpensive, self sustaining flow rate monitor that can be used to identify anomalies in an irrigation system and wirelessly communicate the status of the system to a base station. Our implementation can also determine the direction of the anomaly based on the nature of the anomaly itself. This means that multiple monitors can be used to pinpoint the location of a break within the system in addition to merely detecting its …

Optimizing The Physical And Nutritional Environment Of Unleached Root-Zones, Curtis B. Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unleached root-zones represent an environmental ideal by eliminating wasteful leaching of nutrients and water. NASA grows plants in space in unleached root-zones, incorporating polymer-coated fertilizer (PCF) into a ceramic media (Turface or Profile). However, lack of growth productivity in space has led to the need for research to improve the nutritional and physical environment of the root-zone, which is the objective of this research. PCF types are diverse in release characteristics and the effects of temperature and substrate water content have not been well characterized. In spite of widespread use, studies on chemical properties and applied studies to verify soil …

Mathematical Modeling Of Light Utilization And The Effects Of Temperature Cycles On Productivity In A Steady-State Algal Photobioreactor, Peter Edwin Zemke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The work presented here investigated two methods of improving productivity in microalgal photobioreactors: applying temperature cycles intended to maximize photosynthesis and minimize respiration, and development of a mathematical model that predicts improvements in photon utilization using temporal light dilution (flashing).

The experiments conducted on diurnal temperature cycles with Dunaliella tertiolecta in 30-L outdoor photobioreactors showed that a properly chosen temperature cycle can improve mass and energy productivity by 18% over an identical photobioreactor with a constant temperature. However, excessively large temperature cycle amplitudes reduced productivity. A 4-7% increase in energy content was observed in microalgae exposed to temperature cycles. The …

Effects Of Temperature And Humidity On Glass-Reinforced Nylon Rotating Bands, Marc D. Raby

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Certain 30mm munitions used in various military applications are configured with a glass-reinforced nylon band that acts as a firing ring or rotating band. The purpose of this research is to investigate whether storage environments compromise the strength and integrity of the glass-reinforced nylon rotating bands by researching the environmental factors that will degrade nylon and by performing tests to investigate if these factors will embrittle nylon composites. Moisture and temperature are found to be the environmental factors that will have an effect on the rotating bands in their respective storage environments. Absorbed moisture is found to increase the impact …

Diffuse Degassing And The Hydrothermal System At Masaya Volcano, Nicaragua, Sophie C. P Pearson

USF Tampa Graduate Theses and Dissertations

Hydrothermal systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Fumaroles are a surface manifestation of this interaction. We use time series of soil temperature data and numerical models of the hydrothermal system to investigate volcanic, hydrologic and geologic controls on this diffuse degassing.

Soil temperatures were measured in a low-temperature fumarole field located 3.5 km from the summit of Masaya volcano, Nicaragua. They respond rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. The soil temperature response is repetitive and complex, and …

Analysis Of Mangrove Structure And Latitudinal Relationships On The Gulf Coast Of Peninsular Florida, Peter Novitzky

USF Tampa Graduate Theses and Dissertations

The coastline of Florida has been formed by geomorphic processes which have created suitable habitats for certain vegetation and organisms. One type of vegetation is the mangrove; this plant has a latitudinal range of 24° to 32° N latitude which is associated with local climatic changes (Mitsch 2000). There are three species of mangrove found in Florida: red (Rhizophora), black (Avicennia), and white (Languncularia) (USGS 2006). Mangroves have adapted overtime to live in different ecosystems which cause mangroves, along the Florida coast, of the same species not be the same.

Climatic variation causes individual mangrove trees have structural differences such …

Thermal Analysis Of Natural Convectiona And Radiation In Porous Fins, Mehulkumar G. Maheria

ETD Archive

No abstract provided.

Habitat Conditions And Steelhead Abundance And Growth In A California Lagoon, Kristine Ann Atkinson

Master's Theses

To better understand the temporal and spatial relationships of water quality parameters, as well as steelhead (Oncorhynchus mykiss) habitat use and growth in San Gregorio Creek estuary / lagoon, water quality and steelhead at San Gregorio Creek estuary / lagoon were studied over a period of two years. During both years, there was above-average rainfall, and during the dry seasons of both years the lagoon was repeatedly artificially breached. In spite of the breaching, variations in growth and population size relative to variable sandbar dynamics were measured both within and between years. Data showed that repeated artificial breaching …

Distribution, Abundance, Growth, And Habitat Use Of Steelhead In Uvas Creek, Ca, Joel Malone Casagrande

Master's Theses

Distribution, abundance, growth, and habitat use of juvenile steelhead (Onorhynchus mykiss) were studied in a central California stream under two increased summer flow reservoir release strategies. The effect of habitat quality (including longitudinal changes in flow, water temperature, canopy closure, substrate quality, and turbidity) on abundance and growth of steelhead among sites was determined. Increased stream flow extended rearing habitat and steelhead distribution downstream to reaches that previously would have been dry. Yearling or older steelhead were relatively scarce at all Uvas Creek sites. Steelhead were most abundant, but small, in the upstream half of the study reach, …

Aquatic Ecology Of San Felipe Lake, San Benito County, California, Julie Renee Casagrande

Master's Theses

This two-year study examined San Felipe Lake environmental factors and food-web relationships. The lake is shallow, warm, productive, and generally well-mixed. High turbidity resulted from wind mixing of bottom sediments, carp feeding activity, and plankton blooms and excluded submerged aquatic plants. Emergent vegetation was restricted by cattle grazing. Summer temperatures reached 26-28°C throughout the water column, and dissolved oxygen was occasionally low on the bottom overnight and during windless daytime periods. Phytoplankton, fine organic matter, and detritus formed the base of the food web, supporting a zooplankton community dominated by copepods, the water column macroinvertebrate Neomysis, and several open water …

Low Co-Cultivation Temperature At 20oc Improved Agrobacterium Tumefaciens-Mediated Transformation Of Tobacco Leaf Disks, Guiying Su

LSU Master's Theses

I investigated the effect of co-cultivation temperature and binary Ti vectors on the fresh weight yield of leaf disks of tobacco (Nicotiana tabacum L. cv. Xanthi (nn, Smith) after Agrobacterium tumefaciens-mediated transformation. I concluded that the temperature at 20ºC during co-cultivation of leaf disks with A. tumefaciens was the most critical factor on the reproducible enhancement of fresh weight yield. The highest fresh weight increase and presumably transformation efficiency was achieved under the following experimental conditions: A. tumefaciens strain LBA4404 containing pLSU binary Ti vector was grown overnight at 28oC in liquid Agrobacterium medium and the concentration was adjusted to …

The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman

Electronic Theses and Dissertations

This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in …

The Comparison Of Mitochondrial Functions Of 2 Drosophila Species: Drosophila Ananassae And Drosophila Subobscura, Hye J. Shin

All ETDs from UAB

Recently, it has been suggested that differences in mitochondrial function enabled Homo sapiens to migrate out of Africa by enabling humans to adapt to colder environments as they migrated to higher latitude areas. Through mitochondrial mutations that partially uncoupled oxidative phosphorylation, humans that moved to colder areas were able to generate more heat for better survival, while producing less energy. However, due to challenges in working with human populations, no specific studies have been able to show the existence of such differences in mitochondrial function within healthy humans. Because of numerous advantages of Drosophila as a developmental model, such as …

Temperature And Frequency Dependent Conduction Mechanisms Within Bulk Carbon Nanotube Materials, John Simmons Bulmer

Browse all Theses and Dissertations

The resistance of three types of bulk carbon nanotube (CNT) materials (floating catalyst CNT yarn, forest grown CNT yarn, and super acid spun CNT fiber) was measured from room temperature to 900 C. Fitting the curves to established conduction equations for disordered materials, competing conduction mechanisms pertaining to the material could be determined. Floating catalyst CNT yarn displayed both semiconductive and metallic isotropic behavior with a resistance minimum, similar to the behavior of crystalline graphite. It was found that, at room temperature, the semiconducting contribution-most likely junctions between CNTs-accounted for 99.99% of the overall resistance. The resistance of forest grown …