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Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xix, 193 p.; also includes graphics. Includes bibliographical references (p. 181-193).

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The work described in the thesis is concerned with making new polymeric materials via ring opening metathesis polymerisation (ROMP) using a well-defined ruthenium carbene as an initiator. The object of the study was to provide a process for producing shaped articles by introducing a reactive liquid mixture into a mould in which the reacting liquid mixture undergoes ROMP in the bulk to produce the moulded article. Mono- and difunctional imidonorbomene derivatives were used as monomer and crosslinker respectively. The properties of the cured samples were determined by sol-gel analysis, DSC, TGA, nmr and IR spectrometry. Gel fraction, Tg and content of unreacted monomer were used to characterise the cured samples. The results indicated a strong dependence of the polymers appearance and properties on the polymerization formulation and protocol, i.e. the monomer, the crosslinker and the polymerization conditions. The relative reactivity of the exo- and endo-monomers was investigated using the 'Hnmr technique since the initiation and propagation steps of the polymerisations can be followed in detail by this technique. The results showed that the polymerisations are living and the exo-isomer is more reactive than endo-isomer. A wider range of polymers can be prepared from solution polymerisation as compared to bulk polymerisation. The polymers derived from solid monomers, the monofunctional monomer with short N-alkyl pendant groups and all the difunctional monomers, could be prepared more easily in solution than in bulk polymerisation. The endo-monomer and the monofunctional monomer with long N-alkyl pendant group showed very low reactivity and were not suitable for ROMP in bulk but underwent solution polymerisation. It was found that the thermal properties of the linear polymers depend upon the amount of each monomer isomer incorporated into the polymer chain and the ength of the N-alkyl pendant groups. All linear polymers are soluble in chlorinated solvents from which clear films can be cast. The work described establishes conditions for production of fully crosslinked solids with only traces of the sol fraction.

The first steps towards the long term objective of building entirely synthetic organic/inorganic composite materials in a biomimetic manner have been achieved. Following an introduction and discussion of the background to the work (Chapter 1), the syntheses and characterisation of various molecular weights of both poly(exo, exo-1,4-cyclopentenylene-5,6-ethylidene-2,3-sodium dicarboxylate) and poly(exo,endo-l,4-cyclopentenylene-5,6-ethylidene-2,3- sodium dicarboxylate) and model compounds of their repeat units have been described (Chapters 2 and 4). These compounds were used as additives in the crystallisation of CaCO(_3) from supersaturated aqueous solutions of Ca(HC0(_3))(_2) (Chapters 3 and 5). The work described in Chapter 3 showed that the diacid model compounds used as additives controlled the morphology of calcite crystals grown from supersaturated solutions of Ca(HCO(_3))(_2) over a large range of concentrations of model compound; [Ca(^2+)]: [model compound] 10 to 1000:1. The polymers of these monomers appeared to give the same type of crystal morphology as the isolated model repeat units, however, modification was observed on only one face of the CaCO(_3) crystals. This observation, and the relatively small crystal size distributions measured, indicated that the calcite crystallisation was nucleated beneath the polymer films at the truncated modified face and growth continued down into the solution.

Thesis (Ph.D.)--Tufts University, 2003. / Director: David L. Kaplan. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 160-175). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Many aircraft are designed using the Damage-Tolerance concept. This concept assumes that a structural component is flawed during the manufacturing process. A central feature in this concept is the fatigue-crack-growth-rate properties of the material used in its construction. ASTM E-647 standard describes how fatigue crack growth tests are to be conducted. In the late 1960’s, Wolf Elber discovered the concept of crack closure. He showed that the crack would close prematurely even while under tensile loading. A central feature in this concept is called the crack opening load. The method in ASTM E-647 used to calculate the crack opening load has been found to be inadequate for high load ratios R (Pmin/Pmax>0.4) tests. Herein, an algorithm implementing the least squares method was developed to determine the crack-opening load for low and high R tests on a variety of materials for fatigue crack growth tests conducted on compact C(T) specimens.

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This thesis aims to explore architectural experience by addressing how different types of openings exert an impact to the space. The openings not only play a critical role in giving a palpable presence to natural light in a space, but also facilitate a specific way of seeing the world – together generating a spiritual resonance through a sequence of well-designed spaces. The journey happens in a four-story tower, which is influenced by four parts of a tree, providing a space to experience tranquility removed from a chaotic world and to gain a deeper understanding of the trees. With an emphasis on the manipulation of natural light and views, certain kinds of atmospheres are created on each floor to shape the perception of space. / Master of Architecture

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