No description available.

Univ., Diss.--Kiel, 2006. / Literaturverz. S. XXXVII - LIII.

Thesis (doctoral)--Technische Hogeschool Delft, 1985. / Summary in Dutch. On leaf of "Stellingen" inserted. Includes bibliographical references (p. R-1-R-22).

Thesis (doctoral)--Technische Hogeschool Delft, 1985. / Summary in Dutch. On leaf of "Stellingen" inserted. Includes bibliographical references (p. R-1-R-22).

Thesis (Ph. D.)--Yale University, 1990. / Includes bibliographical references (leaves 267-279).

Thesis (M.A.) --Florida State University, 2006. / Advisor: David A. Cartes, Florida State University, College of Engineering , Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Jan. 2, 2007). Document formatted into pages; contains viii, 61 pages. Includes bibliographical references.

No description available.

Ultrasonic water treatment is based on the ability of an ultrasonic device to induce cavitation in the liquid, generating physical and chemical effects that can be used for biological inactivation. Effective treatment requires the ultrasonic device to generate intense cavitation field in a large treatment volume. Most conventional ultrasonic radiators fulfil only the first of these two requirements, rendering such devices highly unsuitable for use in high-volume, high-flow liquid processes. The present research investigates the design and performance of a new type of radial resonator in terms of their electromechanical characteristics, nonlinear behaviour, and their ability to treat synthetic ballast water with lower power consumption and short treatment times. The radial resonators were designed using finite element (FE) modelling, and the best designs related to their predicted modal behaviour and vibration uniformity were selected for fabrication and experimental evaluation. Experimental modal analysis (EMA) of the radial resonators showed excellent correlation with the FE models, deviating by only 0.3% at the tuned mode. Impedance analysis showed that the mechanical quality factor of the radial resonators are 28–165% higher than the commercial high-gain probe, but their coupling coefficients are 40–45% lower. Harmonic response characterisation (HRC) revealed shifts in the resonance frequencies at elevated excitation voltages. Duffing-like behaviour were observed in all resonators. RP-1 exhibited the Duffing-like behaviour to a far greater extent compared to the RPS-16 and RPST-16 multiple orifice resonators, indicating the influence of geometric parameters on the overall stiffness of the structure. Finally, experiments with Artemia nauplii and Daphnia sp. showed excellent biological inactivation capability of the radial resonators. Comparison with previous studies showed that 90% reduction in Artemia nauplii can be achieved with up to 33% less energy and using just one radial resonator compared to the dozens of conventional resonators used in precedent investigations. The present research have successfully demonstrated the use of FE modeling, EMA, and HRC to develop, validate, and characterise a new type of radial resonator. Experimental analysis showed that the radial resonators exhibited promising electrical, mechanical, and acoustical characteristics that has the potential to be cost-efficient, scalable, and a viable alternative water treatment method.

Anemometers on Voluntary Observing Ships (VOS) are usually located above the bridge in a region where the effects of air flow distortion, created by the presence of the ship, may be large. Until now it was not known whether measurements from such anemometers would be biased high or low, and the possible magnitude of any such bias was not known. Investigations into the airflow above merchant ships have been carried out experimentally using a low-speed wind tunnel and numerically using a commercial Computational Fluid Dynamics (CFD) code VECTIS. The investigations examined the airflow over simple block models of VOS shapes. The results of the investigations were compared to wind speed measurements made from the RRS Charles Darwin. Experimental and CFD techniques have been used to devise scaling rules that predict the effects of the flow distortion. Both techniques have shown that the pattern of the flow distortion above the bridge scales with the ‘step height’, H, of the model. In the case of a tanker, H is the ‘bridge to deck’ height, i.e. the height of the accommodation block above the deck, for bow-on flows. Close to the top of the bridge the flow is severely decelerated and may even reverse in direction. Using the upwind edge of the bridge as the origin of the scaled co-ordinate system, there is a definite line above the decelerated region along which the speed of the flow is equal to the undistorted wind speed. Above this ‘line of equality’ the wind speed increases to a maximum and then decreases with increased height to a free stream wind speed. Simple equations have been devised to predict the positions of the ‘line of equality’, the maximum wind speed and the minimum wind speed within the decelerated region. Comparisons of the results with wind speed data obtained from field measurements made using a number of anemometers located on the RRS Charles Darwin agreed well and have predicted a maximum wind speed increase of approximately 15 ±5 %. Comparisons with the field data have confirmed that CFD models can be used to predict the effects of airflow distortion above merchant ships. The investigation has demonstrated the ability of the wind tunnel and CFD approaches employed to provide a better understanding of the airflow over merchant ships. Both methods have contributed to improve the understanding of how the wind speed at anemometer sites on merchant ships is affected by the ships hull and superstructure.

Certain civilian uses of the Global Positioning System (GPS) now demand levels of precision exceeding the original military specifications for the system. For example, at present, GPS is used in surveying, navigation and monitoring applications. Although GPS has been used previously to monitor the structural integrity of civilian structures such as bridges and towers, the experimental conditions have one significant difference: These structures are all immobile allowing for fixed references to be used. This research’s ultimate aim was to conduct a feasibility study into the use of GPS, and of the soon to be deployed Galileo constellation, in structural monitoring of maritime vessels. Under these conditions, a fixed base station as was used in previous structural monitoring is not a valid approach. New techniques, or variations on the current ones, were examined to deal with this lack of a fixed reference. This thesis considers the simulator that was developed in the early phases of the project and the results that were generated. An expanded version of the simulator is then explained, alongside the processes used to model structural deformation experienced by a ship at sea. Frequency analysis of the simulator results is also performed and the results detailed. It is found that frequency-domain analysis allows for the identification of different movements seen on the structure. In addition, an analysis of the impact the deployment of the Galileo constellation is conducted using simulation. This simulation found a drop of about 20% in Dilution of Precision (DOP) over several areas. This thesis then examines some of the field work, that aimed to measure rigidbody motion, that was conducted onboard Red Jet 4, a catamaran-type vessel. The experimental setup is described, and the results are briefly considered. A method for determining the optimal configuration of the receiver network is also proposed alongside an algorithm to detect plastic deformation of a vessel structure. Finally, this report considers the original project objectives and how these were or were not met. Should sufficient accuracy be achieved by a GPS receiver network, it is possible to use the system to monitor ship structures.