Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vii, 125 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 90-91).

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 188-199).

Thesis (doctoral)--Kungliga Tekniska Högskolan, Stockholm, 1982. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Jorge G. Zornberg. Vita. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1987. / Vita. Abstract. Includes bibliographical references (leaves 175-179). Also available via the Internet.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 23, 2007) Includes bibliographical references.

The durability in the lung of inorganic fibrous materials, such as asbestos and man-made mineral fibres, appears to be a major determinant of their pathogenic potential. However, studies have been inadequate in explaining differences in the physiological durability of such inorganic fibres. This study used an iterative approach to determine key factors affecting physiological durability of a soda-lime silicate bulk glass, A-glass, E-glass, Lead-glass, Cemfil and alumino-silicate ceramic fibres. The aims were to develop a) the current theoretical understanding of durability and b) a suitable in-vitro screening test for durability. Materials were exposed to simulations of the lung environment, which included a) exposure to Gamble's fluid, water, serum and other simulated fluids, b) long-term exposure to the intra-macrophage environment and c) exposure to rat lung. Durability was characterised by scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray microanalysis (EDXA). The use of secondary ion mass spectrometry (SIMS) was also explored, though further development was required in this area. Fibre behaviour depended on fibre composition and thenature of the exposure environment. The ceramic was durable in all environments, whilst A-glass, Lead-glass and the soda-lime silicate were prone to nucleophilic attack and leaching. The effects of in-vivo exposure were consistent with the response in-vitro. However, exposure to the intramacrophage environment in-vitro did not affect fibre durability and this surprising result should be investigated. Physiological durability was related to the ability of the fibre to resist nucleophilic attack and a hybridization bonding model was examined in order to explain the behaviour of some silicate glasses. It was recommended that models based on the molecular bonding were developed to encompass a wider range of materials. Occupational exposure and inhalation of asbestos fibre can cause lung disease and although the mechanisms of asbestos pathogenicity remain uncertain, attention has also focussed on the potential effects of other inorganic fibres. Comparative studies on behaviour of these materials in the lung have strongly implicated the durability and hence lifetime of the fibre to be a major determinant of the pathogenic potential. However, durability studies have generally been inadequate in explaining differences in physiological durability of inorganic fibres and hence provision of theoretical models. This study used a novel iterative approach to determine key factors affecting physiological durability of a range of glass and ceramic materials. The objective was to develop the theoretical understanding of the durability of inorganic fibrous materials in the lung and appraise in-vitro methods for determination of fibre durability to validate a suitable screening test. The durability of a range of glass and ceramic materials has been characterised using in-vitro and in-vivo simulations of the human lung environment; novel exposure systems have been developed and durability behaviour has been characterised by application of traditional analytical methods and by development and application of secondary ion mass spectrometry (SIMS) techniques. Appraisal of in-vitro simulations revealed that fibre behaviour depended upon fibre composition and exposure conditions' durability of the fibres in-vitro was related to model fluid pH. Fibre response in-vivo was rationalised by assuming localised pH variation. This work supports the use of a range of in-vitro exposure conditions to identify key determinants of fibre durability and to characterise chemical behaviour, and is critical of the use of single in-vitro screening tests which will reflect fibre behaviour under specific conditions. Resistance of the inorganic fibre network to hydrolytic attack was suggested as a key determinant of durability and a theoretical model was developed to predict this.

The classical problem of pullout of a long elastic rectilinear round bar (fiber) embedded in an elastic half-space (matrix) is considered before and while local debonding occurs. An approximate analytical solution derived from the elasticity theory, the intuitive Saint Venant's principle, the idea of boundary layer in hydrodynamics, and invariant Γ-integrals is presented. The problem is analyzed numerically by means of the finite element method using the ANSYS program. The cases of loading before and after the initiation of the debonding are studied. Both approaches, analytical and numerical, are compared in order to establish the concidence between them. The discrepancy is very small in the global sense though substantial differences appear at particular points.

A thesis submitted in compliance with the requirements for the Master's Degree in Technology: Mechanical Engineering, Durban Institution of Technology, 2003. / Composites have become important engineering materials, especially in the fields of automotive, aerospace and marine engineering. This is due to the high specific strength and stiffness properties they offer. At present, fibre-reinforced plastic (FRP) laminates are some of the most common types of composite used. They are produced in various forms with different structural properties. As with all engineering materials, there is the existence of both advantages and disadvantages. One of the main disadvantages is the expense involved in producing both the material and the finished product. The design time is also costly as the material has to be designed concurrently with the structure. / M

A new method to fabricate continuous graphite fiber reinforced aluminum alloy composites has been developed and the tensile properties of the composites have been investigated. Composites with 601, 201 and 7178 alloy matrix containing up to 19 volume per cent of Thornel 50 graphite fiber were studied. These composites showed lower tensile strength values than the expected values from the "rule of mixture". A theoretical model is discussed in order to understand the tensile properties of these composites. In this mechanism, graphite fibers are thought to be broken continuously one after another at maximum loading point of ultimate tensile strength during the tensile test. A further attempt has been made to improve the tensile strength of these composites, based on the above theoretical work. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate