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In the design of piping systems the importance of the pipe bend is well established. Recent publications have been increasingly concerned with the effect of end constraints on the behaviour of smooth pipe bends. This has been aimed almost exclusively at in-plane bending, there being no serious attempts at the solution to out-of-plane bending. In PART (1) of this thesis a theoretical solution is presented for the out-of-plane bending of linear elastic curved pipes with rigid flanges. The analysis employs the theorem of minimum total potential energy with suitable kinematically admissable displacements in the form of fourier series. Integration and minimisation is performed numerically. Results are given for a wide range of practical bend geometries. A comparison with previous theoretical predictions highlights the inadequacy of these earlier solutions. The present results are shown to be in favourable agreement with results from tests conducted by the author and more recent results using a different solution procedure. Work in the creep of pipe bends necessitates a substantial amount of experimental work and expertise. Most publications dealing with the creep of pipe bends under bending loads fail to present much information on this aspect. In PART (2) of this thesis a general description is given of an experimental creep programme on pipe bends. The measurement of strain at elevated temperature was accomplished using the CERL-PLANER capacitance strain gauge. It is shown that the application of this gauge to pipe bends requires particular techniques if meaningful results are to be obtained. The results of development work arising from other problems encountered during the test programme are also presented. These include the measurement of displacement and distortion at elevated temperature and the provision of an efficient and novel heating system.

Performance of air operated valves is a major maintenance concern in process industries. Anecdotal information indicates that reliability of some high maintenance valves has been improved by using an ion deposition process to achieve engineered surfaces on selected components. This project compared friction for various surface treatments of selected valve components. Results indicate valve performance may be slightly more consistent when an engineered surface is applied in the valve packing area; however surface treatment in this area does not appear to have a dominant affect on reducing valve friction. Results indicate a linear relation between stem friction and torque applied to packing flange nuts, and even after a valve is in service, controlled packing adjustments can be made without significantly changing valve stroke time.

The gold standard treatment for patients with AVD is surgical replacement of the aortic valve with either mechanical or fixed tissue prostheses. These implants have a limited lifespan and are associated with serious adverse events. Patient autologous tissue engineered heart valves (TEHVs) offer a solution. Vital to the development of a TEHV is determining a source of donor tissue(s) that most closely mimics the native valve tissue. In pursuit of determining an alternative cell source for patient autologous TEHVs we compared a number of phenotypic and genotypic characteristics of atrial fibroblasts, dermal fibroblasts and differentiated bone marrow-derived progenitor cells (BMCs) and made a comparison to valvular interstitial cells (VICS). We demonstrate that while VICs share some phenotypic similarities with fibroblasts and BMCs, they also possess unique characteristics and demonstrate differential mRNA expression of key regulatory pathways that may influence their phenotype. / October 2016

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