The purpose of this paper is to study the design of robust control for a flexible beam. First, the finite element method (FEM) is used to formulate the ordinary differential equations (ODEs) of the dynamic system of the beam model, and a controller is designed via the H-inf control theory. From the computer simulation results, the following conclusions could be drawn. 1. The developed controller is capable of precision positioning and tolerating external disturbance. 2. The robust stability for the system is assured. Furthermore, robust control of linear one-dimensional systems is extended here to two-dimensional systems. The finite difference method (FDM) is applied to partial differential equations (PDEs) to obtain the so-called Roesser discrete state-space model. We discussed the application of H¡Û control for two-dimensional systems and the design of H-inf controller is formulated into a convex optimization problem characterized by linear matrix inequalities (LMIs). Finally, the solutions of the LMIs are then used to construct a two-dimensional H¡Û controller.

In this study, particle impact damping is measured for a cantilever beam with a particle-filled enclosure attached to its free end. Many particle materials are tested: lead spheres, steel spheres, glass spheres, tungsten carbide pellets, lead dust, steel dust, and sand. The effects of particle size are also investigated. Particle diameters are varied from about 0.2 mm to 3 mm. The experimental data collected is offered as a resourceful database for future development of an analytical model of particle impact damping.

The effect of electron beam irradiation upon microbiological quality and safety of fresh-cut tomatoes was studied. Preliminary studies were conducted to ensure reliability of the rifampicin-resistant strain versus the parent strain of Salmonella serovar Montevideo for use in this study. Growth curve, heat tolerance and lactic acid resistance studies were performed, all of which showed no differences in behavior between the organisms. Fresh tomatoes were obtained from a local supplier and then cut into cubes with stem scars being separated. Both cubes and stem scars were inoculated with a rifampicin- resistant strain of either Salmonella Montevideo or Salmonella Agona, separated into treatment groups and treated by electron beam irradiation at 0.0 kGy (control), 0.7 kGy or 0.95 kGy. The effect of electron beam irradiation was determined for Salmonella, yeast, mold, and lactic acid bacteria (LAB) populations as well as pH on tomato cubes and stem scars over a 15-day storage period at 4??C. Results indicated that while irradiation treatment significantly reduced most microbial populations on tomato samples, there were no differences in the microbial populations between treatments of 0.7 kGy or 0.95 kGy. Irradiation at either dose resulted in a significant reduction of Salmonella Montevideo when compared to the control, with an initial reduction of 1.8 and 2.2 log10 CFU/g on tomatoes for 0.7 kGy and 0.95 kGy, respectively. LAB, yeasts and molds were more resistant to the treatment than Salmonella. Populations present on stem scars and tomato cubes did experience some differences in log reductions, possibly due to the protective effect of the stem scar on microorganisms. However, no differences were detected between the two Salmonella serotypes in response to irradiation treatment. This study indicates that doses of irradiation greater than 1 kGy should be used in fresh-cut tomatoes to eliminate significant populations of pathogens, as well as to ensure the microbial quality of the product. Additional studies also need to be conducted to examine the effects of higher irradiation doses on the sensory qualities of fresh-cut tomatoes.

In this study, the AZO thin films were deposited with various manufacturing conditions, such as working pressure of oxygen and substrate temperature, by e-beam evaporation. The microstructure of the AZO film was observed by SEM and AFM. Sheet resistance was measured using four-point probe method. Optical transmittance was measured in the visible range by UV spectrophotometer. Finally, AZO transparent film was used as a substitute for ITO to fabricate the radiation-resistant glasses. The optimum parameters for depositing AZO films are glass substrates of 80¢J and working pressure of 1¡Ñ10-4 Torr. The film resistance is 9.2¡Ñ10-4 £[-cm with a film thickness of 60 nm. The refractive index was measured to be 2.05 at a wavelength of 510 nm. The optical transmittance of the prepared films was above 83 % in the visible range. The manufacturing conditions for depositing AZO multilayer coatings are working pressure of 5.0¡Ñ10-5 Torr, ion gun working pressure of 6.0¡Ñ10-5 Torr, voltage of 6.2 V, oxygen gas flow rate of 36 sccm and glass substrates of 80¢J. The optical transmittance of the glass was above 94 % in the visible range.

The present work researches influence of energy focusing effect to the fusion zone defects in the electron beam welding, which include fusion zone shape, welding depth, welding width, rippling and spiking. And to verify the model of welding defects base on theory and experiment. A spike is a sudden increase in penetration beyond what might be called the average penetration line. Many spikes have voids and cold shuts in their lower portions, because molten metal does not fill in completely, producing a condition similar to a cold shut in a casting. Ripples on a workpiece surface are generally associated with segregation, porosity and other microstructure defects. These become the objectives in this project.

Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xvii, 161 p. : ill. Includes abstract. Includes bibliographical references (p. 154-161).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Physics and Astronomy." Includes bibliographical references (p. 160-164).

Thesis (Ph. D.)--School of Electrical and Computer Engineering, Georgia Institute of Technology, 2004. Directed by Gary S. May. / Includes bibliographical references (leaves 109-113).

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 44-48). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Archie L. Holmes, Jr. Vita. Includes bibliographical references. Also available from UMI.