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Approved for public release; distribution is unlimited / Internal solitary waves, or solitons, are often generated in coastal or continental shelf regions when tidal currents advect stratified water over bathymetric relief, creating an internal tide which non-linearly evolves into one or more solitons. A major consequence of solitons in a stratified environment is the vertical displacement of water parcels which can lead to sound speed variability of order 10m/s with spatial scales of order 100 meters and timescales of order minutes. Thus significant variations in sonar performance on both surface based ships and submarines can be expected. An understanding into the nature of acoustic propagation through these waves is vital for future development of sonar prediction systems. This research investigates acoustic normal mode propagation through solitons using a 2D parabolic equation simulation and weak acoustic scattering theory whose primary physics is a single scatter Bragg mechanism. To simplify the theory, a Gaussian soliton model is developed that compares favorably to the results from a traditional sech2 soliton model. The theory of sound through a Gaussian soliton was then tested against the numerical simulation under conditions of various acoustic frequency, source depths, soliton position relative to the source and soliton number. The theoretical results compare favorably with numerical simulations at 75, 150 and 300-Hz. Higher frequencies need to be tested to determine the limits of the first order theory. Higher order theory will then be needed to address even higher frequencies and to deal with weakly excited modes. This research is the first step in moving from a state of observing acoustic propagation through solitons, to one of predicting it. / Outstanding Thesis / Royal Australian Navy author

Many species from economically important genera remain rooting recalcitrant, prohibiting the commercialisation of many species in forestry and horticulture, and hindering genetic improvement by conventional breeding or recombinant DNA technology, where vegetative propagation is often used to preserve the genetic fidelity of elite progeny. Two cherry species (Prunus avium and P. padus) were used as models in this study to investigate the physiological and genetic manipulation of adventitious rooting. Mature trees are typically more difficult to propagate vegetatively than their juvenile counterparts. For some trees, micropropagation can circumvent certain effects of ageing and maturation, restoring shoot vigour and rooting, but the mechanism(s) involved have not been elucidated. During micropropagation, subculture interval was found not to be the predominant factor promoting the 'apparent rejuvenation' of mature P. avium tissue. 'Apparently rejuvenated' ex vitro and hedged (putatively) mature P. avium trees were treated with gibberellins predicted to have a range of structural related activities. GA, improved the rooting of cuttings from hedged (putatively) mature cherry, but not from ex vitro trees. Methodology to regenerate adventitious shoots from P. avium leaf explants was developed, (putative) transgenic P. padus plants were produced by an Agrobacterium tumefaciens mediated strategy. Auxin redistribution in planta is postulated to require a component of active transport; inhibition of the predominantly basipetal transport has profound effects on rooting. The putative function of the Arabidopsis thaliana AtAUX1 gene is that of a cellular auxin influx carrier, possibly, as described by the chemiosmotic hypothesis. This thesis examined the hypothesis that transformation with the AtAUX1 gene would enhance the delivery of the root-inducing signal to improve rooting of P. padus, a species which is rooting recalcitrant and more or less obligate on exogenous auxin for this process. However, all six, constitutively expressed, Cauliflower Mosaic Virus 35S promoter driven, 35S::AtAUX1, transgenic shoot lines had reduced rooting.

Digitized by Kansas Correctional Industries

In the oil and gas industry, threaded pipe connection is frequently used to connect the casing string, drill pipe strings or production and transportation risers and pipelines. The connection is normally preloaded in order to maintain a sealed and secure connection while in service and avoid leakage. Tapered thread are a common connection and in order to introduce preload to the threaded connection when they are assembled a certain make-up torque is going to be applied. The make-up torque plus external loads result in a multiaxial stress distribution over the connection, where the threaded connections act as stress risers. Environment such as waves and currents cause dynamic loads acting on the pipe line and offshore structures. The weakest point in offshore structure is the pipe connection because of fatigue crack initiated in the connection's threads. Researchers and engineers developed a variety of patented threaded pipe connection which all claiming to improve a connection's fatigue life. The experimental data for patented designs, available in literature, is limited. Most published studies usually comprise experiments on a single connection type. For detailed fatigue analysis those published studies cannot be used since there is no uniformity in testing setup, loading conditions and damage detection technique exist. Moreover, current design curves in codes and standards lead to overly conservative or inaccurate results. The aim of this work is to provide a better understanding of the fatigue mechanisms of threaded pipe connections and to study the effect of different design features on a connection's fatigue life. The final goal is to formulate guidelines for new fatigue resistant connection designs. API connection is used as a reference in this study. Several modifications and design features are applied to the connection type. To simulate the effect of these modifications, a parametric 2D axisymmetric finite element model, ABAQUS is used. 2D finite element result are compared with a 3D model to prove its validity for both make-up. In addition, the results of the 2D axisymmetric simulation are validated by static strain gauge measurements during a make-up test and an axial tension test. The validated model is then used to evaluated the influence of the connection properties and design features on the threaded connection's behaviour. Test rigs were designed to perform axial fatigue experiment on two scales: the small-scale experiments on 1" (33.4 mm outer diameter) connections are performed in axial fatigue testing, the medium scale tests on 4.5" (114.3 mm) connections are carried out under axial tension for which a setup is developed. The majority of the performed fatigue tests are small scale experiments. Several modified configurations are tested. The S-N curve is constructed, so that the effect of certain configuration on the connection's fatigue life can be quantified. The local modification of the threaded connection's geometry as well as the connection's contact condition's contact conditions can have an important influence on the fatigue life of the connection. A beach marking technique is used to visualized the crack fronts at different moments during the tests so that exact crack shape can be seen during post-mortem analysis. The result shown that a crack initiates at the root of the last engaged thread of the male part of the connection, and propagates slowly over a large segment of the circumference, forming a long shallow crack. When the crack penetrates the pipe wall, it rapidly increases in size along two crack fronts. The shape of crack observed in beach mark analysis do not have a semi-elliptical shape as commonly used in fracture mechanics. A fatigue crack growth analysis that considers the crack as an annular flaw, is effective in describing the crack growth behaviour. The experimentally obtained S-N curves and the result from the finite element simulations are combined in multiaxial damage evolution law. The observed trend in fatigue lives of the configuration are explained by using the fatigue analysis. Using a connection's thread load distribution as a measure for its fatigue life is proven to be inaccurate. The main reason for this is that the load distribution is related to axial stresses over the connection. The fatigue life of a threaded connection is determined by the local multiaxial stress distribution and strain range around the root of the last engaged thread. These local conditions are not only the result of the load distribution, but they are also affected by the hoop stress introduced during make-up, which can additionally be affected by a changed connection stiffness. The multiaxial damage evolution law is used to analyse the influence of several features on a connection's fatigue life. It is not for all patented modifications that an increased fatigue life is predicted when applied to the API connection. The final conclusion reached is that, in order to optimize a fatigue resistant connection, several design features must be combined together. The thread shape can be optimized to obtained a low stress concentration factor and reduce the local strains at the thread root. The connection's global geometry and make-up conditions can be optimized to improve the load distribution over the threads and reduce local stresses and strains at the threads.

The purpose of this study was to consider how the rooting of cuttings may be affected by such methods and factors as: type of cutting, time of year when cuttings are best taken, differences between individual species, use of chemicals for the treatment of cuttings, rooting media, and the care of cuttings in the propagation beds. In the past 35 years scientists have done considerable experimenting with the application of organic chemicals on the roots, stems and leaves of various plants. These organic chemicals have come to be known as "plant hormones" or "plant regulators." They have proved to be extremely useful and have affected the plants in rather unusual ways. Growth regulating chemicals are no longer on trial. They now are being used with several kinds of farm crops and ornamental plants. Hormones or growth regulators are chemical substances, made in one part of an organism and transported to other parts where they produce their effects, and they are effective in very minute amounts. This paper will give the present status of knowledge on the use and effectiveness of growth regulators in plant propagation.

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