Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Jeremy M. Firestone, College of Marine & Earth Studies. Includes bibliographical references.

Underwater autonomous vehicles are frequently used for deep-water ocean applications such as surveying and cable-laying, where accurate control of vehicle depth and attitude is needed. The water level in the on-board ballast tanks are typically manually set for neutral buoyancy before each mission, while the vehicle is on the surface. The resulting weight of the water level is not normally adjusted while the unmanned vehicle is in operation to control vehicle depth and orientation. As a result, vehicle trajectory and orientation is exclusively controlled using the vehicle’s control surfaces during a mission. The challenges with controlling the depth and trim of an underwater vehicle include nonlinear hydrodynamic forces as well as relatively slow response times and inherent time delays (latencies) associated with water tank level changes and valve adjustments. To meet these challenges, this thesis proposes two unique variable ballast system control approaches. The proposed control approaches may be suitable for large autonomous underwater vehicles with both small (volume = 0.027 m3, each) and large (volume = 0.216 m3, each) ballast tanks. The first proposed variable ballast system controller uses the current parameters of the ballast tanks to determine the appropriate action to be implemented. This controller was designed change the weight of the AUV to help control vehicle parameters such as depth and vertical (inertial) velocity. The second proposed variable ballast controller attempts to shift the center of gravity x_G along the body-fixed x-(longitudinal) axis by changing the weight in the ballast tanks. By shifting the center of gravity, the controller attempts to reduce depth and pitch angle error while regaining control authority to the bowplane and sternplane deflection fins. The ballasting system consists of two water tanks positioned aft and forward of amidships. The ballast tanks are then automatically filled or emptied of ocean water as desired. Setpoint depth control and x_G shifting numerical simulations have been carried out on a two-dimensional underwater vehicle simulator to test and compare the performance of the proposed ballast and deflection control systems. The simulation results show that, for the assumptions and conditions tested, the proposed controllers are versatile and capable of achieving a setpoint depth and pitch angle with minimal error by effectively utilizing the ballast tanks and deflection fins. As a result, the work presented in this thesis helps increase the autonomy of large AUVs on long duration missions.

Railway track ballast fouling is an ongoing issue without a clear understanding regarding either the cause for generation or the source of the fouling materials. This study was conducted to determine what physical processes are likely causing ballast fouling, where in the track sub-structure fouling material is concentrating, and what factors affect the severity of ballast fouling. A field investigation on a CN railway track was conducted in Joliette, QC during undercutting maintenance operations. Data for in-situ ballast, sub-ballast, and subgrade samples were gathered from a series of trenches excavated through the track embankment. The geotechnical and mineralogical characteristics of a selected set of ballast samples were gathered through a regime of laboratory testing. Grain size distribution data for the select samples was collected from sieve and hydrometer testing. Three sets of LA abrasion tests were conducted on both in-situ and freshly quarried ballast rock to determine the degradation characteristics of the various ballast types. The petrographic analysis of the sample types was conducted using bulk hand sample characterization, thin-section analysis, and X-Ray Diffraction Analysis. The petrographic, grain size, and LA abrasion combined analysis indicated that ballast fouling was primarily caused through degradation of the ballast. The fouling material within the ballast pores was sourced to the abraded pieces of ballast that had degraded over time through XRD and grain size distribution analysis. It was found with statistical confidence that ballast layers with harder, structureless rock types have less fouling material form within the ballast void spaces compared to ballast rock types that are soft on the Mohs hardness scale or have planes of weakness due to structural factors. Analysis of the grain size data also showed that ballast fouling was generally concentrated within the section of the ballast layer directly underlying the steel rail, within the topmost parts of the ballast layers. Overall it was recommended that the effects of chemical degradation on ballast rock types and the historical operational duration of ballast be incorporated into future ballast fouling studies. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2011-09-27 10:01:46.141

The transportation of organisms in the ballast water of cargo ships has been recognized as a source of invasive species despite current control measures. Pathogenic bacteria in the ballast tank have been studied but the total diversity of the ballast tank bacterial community has not been examined. This study is the first to characterize the total bacterial community within a ballast tank by constructing a clone library from a ballast water sample from a cargo ship in the Port of Houston, amplified ribosomal rDNA restriction analysis (ARDRA) and phylogenetic analysis. Bacterial communities in Texas ports and bays were also examined using denaturing gradient gel electrophoresis (DGGE), looking at both temporal and spatial variations for effects of deballasting activity. This ballast tank bacterial community had a high level of diversity (95%) with the clone library only representing 40% of the total community of the tank. Most probable originating habitats of the ballast bacteria were: marine pelagic (40%), estuarine (37%), coastal (6%), freshwater (3%) and other (14%), even though this ballast tank was exchanged with pelagic water. Predominate groups were alpha- and gammaproteobacteria, a few betaproteobacteria and bacteriodetes, and one each of verrucomicrobia, planctomycetes and actinobacteria, but no pathogens were detected. The data reveals a ballast tank that consists of half marine-pelagic, half port bacteria, revealing a low efficacy of exchange control methods and potentially invasive bacteria. The bacterial communities of five ships that exchanged ballast water in the Pacific Ocean shared on average 50% similarity. Two ships that exchanged ballast water in temperate latitudes were more similar than three other ships that exchanged in tropical latitudes, showing a correlation between location of exchange and community similarity. The bacterial communities of the Ports of Houston and Galveston exhibit stable, seasonal successions over one year. The port and bay systems of Texas exhibited spatial variations in bacterial communities related to salinity levels. Both experiments did not show evidence of community disruption by deballasting activities. This study shows that ballast water is a viable vector for invasive bacterial transport, although impact on Texas estuarine systems seems minimal.

In a conventional electronic ballast for a fluorescent lamp, inductor-capacitor-transformer tank circuit is used. A Piezoelectric Transformer (PT) can potentially be used to replace such a tank circuit to save space and cost. In the past, ballast design using a PT requires selecting a PT from available samples which are normally not matched to specific application and therefore resulting in poor performance. In this thesis, a design procedure was proposed for designing a PT tailored for a 120-V 32-W electronic ballast with high power factor, high efficiency and Zero-Voltage-Switching (ZVS) of the inverter transistors that drive the lamp. This involves selection of PT materials, determination of geometries and the number of physical layers of the PT. A radial mode piezoelectric transformer prototype based on this design process was fabricated by Face Electronics Inc. and was tested experimentally, the results showed that the ballast using this custom-made PT achieved high power factor, Zero-Voltage-Switching and a 83% overall efficiency. / Master of Science

This study investigates the starting characteristics of metal halide lamps. A laboratory electronic ballast was built to drive metal halide lamps with a programmable low-frequency square-wave current. The lamp current at each stage of the starting transient can be independently adjusted. Experiments were conducted on 150-W metal halide lamps. By examining the waveforms of transient voltage, current and power, the starting period can be classified into four stages, breakdown, glow discharging, glow-to-arc transition, and thermal equilibrium. In addition, the stable operation is defined by observing the variations of the lamp arc, lighting spectrum and luminous output. Based on the investigation results, four starting scenarios are presented and examined to learn the different acceleration schemes. Experimental evidence shows that the starting time of a metal halide lamp can be effectively shortened by increasing the lamp current during the start-up transition. More importantly, a specifically-regulated operating power enables the lamp to further enhance the luminance producing, and hence to greatly reduce the starting transient period.

The research searches for an identification strategy which is able to recognize three small-wattage metal halide lamps rated at powers of 20-W, 35-W and 70-W from three world-wide prominent brands of GE, OSRAM and PHILIPS. A two-stage constant-power starting scenario is adopted to successfully start all three kinds of lamps without causing a tremendous power during the identification process. At the first stage, the tested lamps are started by a constant power of 25 W. The 20-W lamps can be distinguished from the others by their relatively high lamp voltages at the 30th seconds after being ignited. Then, the other lamps are driven up to 35 W to manifest the voltage difference of between the 35-W and 70-W lamps, and thus can be recognized at the 40th seconds. After being made out, the lamps are operated at their rated powers. Eventually, a verification checking with protection is introduced to prevent the tested lamps from over power operation. Experiments have been done on numerous new and aged lamps. The experimental results evidence that the electronic ballast with the proposed identification strategy can recognize three lamps¡¦ rated powers correctly during the starting transition, and drive the lamp to its rated power before entering the steady-state.

A Study on the Taiwan Shipping Industries' Perception of the BWM Convention for the BWM Convention Abstract The global trade's commodity has 80% is by the marine transportation way loading, is responsible for the transportation industry the ships to maintain the navigation the security is stable; the ballast water tank will be pumping into the massive ballast water to maintain balanced. Had the research discovery, the loading ballast, if after has not processed properly on the emissions inflow harbor, has in the ballast the pathogen or the micro biology, will destroy the local port territory the biodiversity even to initiate threatens the human health disease, will create the serious economic loss. In order to reduce the ballast the emissions initiation pathogen destruction sea ecology, the International Maritime Organization to draw up the International Convention for the Control and Management of Ships Ballast Water and Sediments (BWM Convention) by the public law binding force, so as to protection marine environment. In this studying, the questionnaire is in view of the shipping company, the shipyard, the ships equipment supplier and the maritime affair related organization and so on four communities. According to the investgating result, finds Taiwan shipping interest cognition ratio less than 50% regarding the new international convention, are worth the anxiety. Expected that produces the marine industrial, gonverment and marine educational intrest in Taiwan shipping facing the international ballast control and management tendency by this studying, and provides one to draw up effectively of reference in accordance to the strategy.

An average of three to five billion tons of ballast water (BW) is transported globally per year; 79 million tons of which is released into U. S. waters. Ballast water is necessary for large ships to maintain balance and stability while loading and unloading cargo as well as during transit. As a ship unloads it’s cargo at a port, it takes on ballast water and then when it loads cargo at the next port, it discharges the ballast water, thus transferring water from port to port. Aquatic organisms are transported around the globe via ballast water. These organisms can potentially cause serious environmental and human health impacts. Historically, transfer of macro-organisms such as fish, snails, and vascular plants via ballast water have been the focus of ballast water research. More recently, microorganisms such as toxin producing dinoflagellates and diatoms i.e. ‘harmful algal blooms’ and pathogenic bacteria (e.g. Vibrio cholerae), have been found to survive in ballast tanks for several weeks. These organisms have moved to the forefront of ballast water management (BWM) trepidations because they compose serious threats to human health as well as Marine Protected Area (MPA) ecosystems such as coral reefs. Ballasting activities of ships calling at the Port of Houston were used as a model for other major ports in U.S. Gulf States. Ballast water management reports, submitted to the U.S. Coast Guard by all overseas vessels calling at the Port of Houston in 2010 were examined for the ballast management strategies utilized prior to docking. Currently, all “coastwise” ships are not required to conduct ballast water exchanges (BWE) if they do not transit beyond the 200nm EEZ. Close inspection of BW management report forms for “overseas” ships determined that the degree of completeness was variable. By comparing the frequency of vessels entering the Port of Houston, ballast water capacities, the management types utilized, and the locations of ballast water exchanges and discharges, it can be concluded that larger vessels present the highest risk of bacterial transfer to coral reefs. Five coral diseases were discovered to be prevalent throughout the ballast management areas their presence has significantly increased in these areas over the past thirty years. The combination of this disease growth along with an increase in shipping and ballast exchanges suggests that the vector at which pathogens are being displaced must lie within the shipping lanes.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 190-212.