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Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: property estimation; composites; fire engineering properties; fire modelling. Includes bibliographical references (leaves I-24-I-25).

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 64-60). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 181-186). Available also in a digital version from Dissertation Abstracts.

Fiber reinforced composites (FRCs) are increasingly used in dentistry with their tooth-matching mechanical, physical and aesthetic properties. The most commonly used FRC products consist of E- or S-glass fibers and methacrylate-based resin matrices. The commonly used methacrylate monomer bis-phenol A glycidyl methacrylate (bis-GMA) has a very high viscosity and possibly leads to a low degree of conversion (DC). In this PhD study, the much less viscous urethane dimethacrylate (UEDMA) was chosen as a replacement for bis-GMA, diluted by hydroxypropyl methacrylate (HPMA) to build up the resin system. This thesis comprises four studies. In study 1, three study groups of 70.6wt%, 49.0wt% and 27.4wt% UEDMA mixed with HPMA in the resin, all reinforced with unidirectional E-glass fibers (42.0vol%), were light-cured for 40 s. The control group had a resin blend of 70.6wt% bis-GMA and 27.4wt% methyl methacrylate (MMA). The prepared specimens were stored dry for 24 h or in deionized water at 37 ℃ for 1, 3, 6 and 12 months. Water sorption up to 40 d and Vickers hardness together with flexural properties after each storage period were investigated. The results suggested that water storage at 37 ℃ induced certain degradation to the mechanical properties of FRC. The group with the highest UEDMA content (70.6wt%) exhibited the lowest 40 d water sorption, the highest hardness and the highest flexural strength and modulus after most storage periods among the UEDMA-containing experimental groups, while the control group had an even better performance in most aspects tested. From study 2 to study 4, the UEDMA content was raised to 70.6wt%, 80.6wt% and 90.6wt%. The three resins, without fiber reinforcement, were tested for the DC after 40 s light-curing and monomer leaching in a 75% ethanol:water solution. Specimens prepared of these three resins reinforced with unidirectional E-glass fibers were tested for 40 d water sorption and mechanical properties (Vickers hardness, flexural properties) after 24 h dry storage, 1 and 3 month deionized-water storage at 37 ℃ and thermal cycling between 5 ℃ and 55 ℃ for 6,000 times. The control group was the same as in study 1. The experimental resins showed higher DC compared to the control resin, while higher UEDMA content was accompanied with lower DC. The resin with highest UEDMA content (90.6wt% UEDMA + 7.4wt% HPMA) exhibited the lowest monomer leaching. The UEDMA-based experimental groups exhibited higher 40 d water sorption than the bis-GMA-based control group. While the group with lowest UEDMA content (70.6wt% UEDMA + 27.4wt% HPMA) showed lowest water sorption among the experimental groups. The bis-GMA-MMA-based FRC specimens showed a superior performance in most tested mechanical properties than the UEDMA-HPMA-based FRCs, and with a higher UEDMA content the mechanical properties were more promising for dental use. Water storage at 37 ℃ might induce some decrease in the mechanical properties, while thermal cycling influenced the mechanical properties in a more complicated way. There is a high potential that a new FRC with adequate chemical and mechanical properties could be developed. Biocompatibility should, however, be carefully arranged in the near future. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

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Stress analysis was performed to determine the maximum stress acting on a railcar coal support-bed, using COSMOS finite element and WFM micromechanics models. The fracture strength of polyurethane impregnated Kevlar 29 fabric, proposed for integration with the railcar structure, was determined experimentally by loading the impregnated coupons in a microcomputer controlled Instron 4505. Procedures to improve the wettability of a Kevlar 29 orthogonal-weave fabric were investigated. Unimpregnated and impregnated coupons of increasing gage lengths were statically tested for tensile strength to check for gage length effect behavior. Fatigue tests were conducted to predict the stress level (endurance limit) below which the impregnated fabric bed can perform without failure for ten years of the service life. The fracture strength of the polyurethane impregnated fabric, after immersion in aqueous solutions of different pH values for seventy-five hours and in ten percent concentrated sulfuric acid solution at 212��F for ten hours, was measured. / Graduation date: 1994

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xii, 147 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 97-100).

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 124 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 103-106).