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In Vivo Microscopic Studies Of Ftsz Self-Assembly Dynamics In Escherichia Coli, Bryant Edward Walker

Doctoral Dissertations

During the first stage of cell division in bacteria, FtsZ filaments form a ring-like assembly, the Z-ring, which encircles the cell’s middle. This filament scaffold recruits a set of enzymes that synthesize the new cell wall, which divides the cell into two daughters. This dissertation addresses two questions related to the formation of the Z-ring. First, what molecular mechanism triggers Z-ring formation? Second, what are the intermediary structures through which the Z-ring assembly proceeds? The experiments are carried out in Escherichia coli (E.coli) bacteria, whose FtsZ molecules are fluorescently labelled. Using quantitative analysis of high temporal and spatial resolution time-lapse …

Increasing The Longevity Of Tungsten Filaments In A Zone Refiner, Byron D. Greenlee

Senior Theses

Zone refining is used for its ability to purify material and grow single crystals. To produce these single crystals, a suspended molten zone, generated by electron bombardment, passes along the polycrystalline stock. During a zone refining run, the filaments that produce the electron bombardment can fail. In this project, the longevity of tungsten filaments in a zone refiner was investigated. A new bombardment geometry was constructed to attempt to increase the longevity of the filaments. The new geometry had a shield machined into it to prevent line-of-sight impurities originating in the molten zone from striking the filaments. It was found …

Measuring Accuracy Of Two 3d Printing Materials, Mudassir Ali

Master of Technology Management Plan II Graduate Projects

Part accuracy is one of the important aspect in the manufacturing industry. The overall inaccuracy of the parts being built by RP technology has been one of the major challenges that need to be overcome. Though all the printing materials come with specifications, but the suppliers and manufactures does not specify the accuracy of the materials. In this study we established a study which compares the accuracy of the materials in consideration and performed an experiment to establish the superiority of a material in terms of accuracy over each other. The purpose of this project was to compare the dimensional …

Al/Cuxo/Cu Memristive Devices : Fabrication, Characterization, And Modeling, Nathan Mcdonald

Legacy Theses & Dissertations (2009 - 2024)

Memristive devices have become very popular in recent years due to their potential to dramatically alter logic processing in CMOS circuitry. Memristive devices function as electrical potentiometers, allowing for such diverse applications as memory storage, multi-state logic, and reconfigurable logic gates.

Catechin, A Novel Root Exudate Of Centaurea Stoebe, Exhibits Pleiotropic Effects On The Soil Microbial Community And Individual Soil Isolates, And Undergoes Chemical Changes With Numerous Abiotic Factors From Soil, Jarrod Leroy Pollock

Graduate Student Theses, Dissertations, & Professional Papers

Allelopathy has been studied for (±)-catechin, a root exudate of spotted knapweed, as a plausible mechanism that facilitates knapweed invasion in North America. Phytotoxic effects are observed in invaded fields as well as greenhouse experiments when employing catechin or growing spotted knapweed, demonstrating similar effects on native plant species. However, many studies ignore the impact of catechin on microbial populations in soil. Understanding the impact of catechin on microbial processes will greatly aid our understanding of how spotted knapweed invasion can alter soil chemistry and biological processes. Chapter 2 will address the impact of soil and media parameters on catechin …

Automated Manipulation For The Lotus Filament Winding Process, Jeffrey V. Anderson

Theses and Dissertations

The filament-winding process produces quality consistent composite parts for many industries. Filament winding allows for consistent quality parts by automating the winding process. A recent development of filament winding is the Lotus process. The Lotus process reverses conventional filament winding by leaving the mandrel stationary and winding composite fiber around the mandrel. The automated Lotus filament-winding machine is controlled by four-axis control manipulating the Lotus ring around a fixed mandrel. This allows Lotus filament winding to wind parts that do not have a linear axis. Lotus filament winding is in its early stages of development. As a second step in …

The Effects Of Electrode Geometry On Current Pulse Caused By Electrical Discharge Over An Ultra-Fast Laser Filament, Matthew Bubelnik

Electronic Theses and Dissertations

The time-resolved electrical conductivity of a short-pulse generated plasma filament in air was studied. Close-coupled metal electrodes were used to discharge the stored energy of a high-voltage capacitor and the resulting microsecond-scale electrical discharge was measured using fast current sensors. Significant differences in the time dependence of the current were seen with the two electrode geometries used. Using sharp-tipped electrodes additional peaks in the time-resolved conductivity were seen, relative to the single peak seen with spherical electrodes. We attribute these additional features to secondary electron collisional ionization brought about by field enhancement at the tips. Additional discrepancies in the currents …

A Method For Winding Advanced Composites Of Unconventional Shapes Using Continuous And Aligned Fibers, Abraham K. Allen

Theses and Dissertations

Advanced composites are extremely strong, rigid, and light, even when compared with advanced metals. Advanced composites are replacing high-tech metals as the material of choice for aerospace engineering. However, the processes used to manufacture advanced composites generally lose some of the properties of the materials by their process limitations.

One process that keeps the theoretically awesome qualities of the composite materials in tact is filament winding. Filament wound parts are used as rocket shells, bicycle frame tubes, drive shafts, pressure vessels, etc. Filament winding is an automated process and makes reliable parts to close tolerances. If a straight tube were …

High Resolution Solar Observations In The Context Of Space Weather Prediction, Guo Yang

Dissertations

Space weather has a great impact on the Earth and human life. It is important to study and monitor active regions on the solar surface and ultimately to predict space weather based on the Sun's activity. In this study, a system that uses the full power of speckle masking imaging by parallel processing to obtain high-spatial resolution images of the solar surface in near real-time has been developed and built. The application of this system greatly improves the ability to monitor the evolution of solar active regions and to predict the adverse effects of space weather. The data obtained by …

An Analysis Of Current Interruption Upon The Behavior Of Light Bulb Filament During Initial Aircraft Impact In Support Of Aircraft Accident Investigations, Daniel J. Larow

Master's Theses - Daytona Beach

The purpose of analyzing annunciator panels, warning, and indicator lamps is to determine the state ("on" or "off") of each light bulb immediately before the impact. Determination of the state of lamps may help investigators determine the probable cause of the accident. The information gained from the lamp's filaments may be used to infer the aircraft's operational parameters prior to impact and to a qualitative appreciation of the severity of the accident. It is generally agreed that upon impact the filament of an unlit bulb will fracture without deformation and the filament of a lit bulb will display plastic deformation …

Predicting Burst Pressures In Filament Wound Composite Pressure Vessels Using Acoustic Emission Data, Frederick R. Kalloo

Master's Theses - Daytona Beach

This work presents a statistical method for predicting the burst pressures in filament wound composite pressure vessels by analyzing acoustic emission data obtained during hydroproof testing. First the acoustic emission data is plotted in the form of amplitude distributions. Then, by using statistical models with characteristics similar to Rayleigh and Gaussian distributions, failure mechanism percentages are found, at which point multiple regression analysis is used to predict burst pressures. Next, the predicted burst pressures are compared to the actual burst pressures and the significance of the data is analyzed using standard statistical theories. The research shows that the predicted burst …