Vestimentifera inhabit hydrothermal vents, cold-water seeps and other marine reducing habitats. The objectives of this study were to analyse phylogenetic relationships among the extant species and their affinities to perviate and moniliferan Pogonophora and Polychaeta. The phylogeny was reconstructed using morphological characters to test phylogenetic hypotheses based on molecular data. Morphological characters were partly extracted from the literature and partly gained throughout study of gross morphological and anatomical investigations and light, transmission and scanning electron microscopy. Three aspects of morphology were examined in detail in nine vestimentiferan species. The excretory system differs among the vestimentiferan species in the number of excretory pores, absence/presence of excretory papillae and grooves and shape of the excretory ducts. The anatomy of the excretory system resembles that shared by the polychaete families Serpulidae, Sabellidae and Sabellariidae. Chaetal ultrastructure and chaetogenesis show patterns similar to uncini in polychaetes. Contrary to published accounts, the septa dividing the opisthosomal segments only bear musculature on their posterior faces. A rudimentary gut and anus are present in opisthosomes of specimens up to adult size. The blood vascular system includes an intravasal body in the dorsal vessel with ultrastructural characteristics similar to intravasal tissue in Terebellidae, Ampharetidae, Flabelligeridae and Serpulidae, and is probably involved in hemoglobin production. Hemocytes were detected in many blood vessels, most of them attached to the vascular lamina. The sinus valvatus is a specialised region of the anterior ventral vessel, apparently unique to vestimentiferans. The wall of the dorsal vessel is formed by myoepithelial cells, representing a coelomyarian type of double obliquely striated musculature. Phylogenetic analyses including a total of 17 vestimentiferan species and three perviate species as outgroups support molecular interpretations that the vestimentiferan species inhabiting basalt-hosted vents of the Eastern Pacific represent a derived monophyletic clade. According to the reconstructed phylogeny, the ancestral habitat of Vestimentifera was deep-water sedimented vent sites in the Western Pacific. Analysis of the relationships among Pogonophora and six polychaete families placed Pogonophora at the base of a clade including Sabellidae, Serpulidae and Sabellariidae. The Oweniidae represent the sister group to this clade. / Graduate

The preionization of a shock tube's gas before the shock passes through it is called the precursor effect. An experimental and theoretical study has been carried out on precursor ionization in an electromagnetic shock tube. The precursor ionization was detected with different types of electric probes and also with photoraaltipliers. Extensive experiments indicated that the ionization was not due to diffusion of particles from the discharge in the shock tube driver. The ionization is primarily caused by radiation from the discharge of wavelengths less than 2000 Å. Radiation from the shock front makes a negligible contribution to the ionization. Langmuir double probe measurements indicated that the gas was about 0.1% ionized and that the electrons in the precursor were not in thermal equilibrium with the gas atoms and ions. The time interval between detection of ionization at two stations was independent of the shock tube gas (air, argon, helium), and corresponded to a propagation speed greater than 1/20 the speed of light. The precursor had a main component lasting about 50 microseconds with ionization proportional to the square of the discharge current. There was also a weaker component which lasted for about 500 microseconds. The experimental results can be understood in terms of a theoretical model based on black body radiation. Considering the driver to act as an infinite slab radiator, whose temperature is a function of the discharge parameters, an expression is derived for the number of photons emitted in some frequency interval. Assuming the electron density to be proportional to radiation absorption from such a radiator, the electron density variation with distance from the driver can be adequately understood. When the shock tube is considered to behave as a transmission line, whose resistance per unit length is proportional to the electron density, one can explain the variation of the shock tube's gas potential both with distance from the driver and with time. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The analysis and design of a hybrid-coupled tunnel-diode amplifier is described, considering both the hybrid junction and the tunnel-diode circuitry. The fundamental theory of the tunnel diode is reviewed. The hybrid junction is in the form of a strip-line directional coupler which makes use of the inherent contra-directional coupling between two adjacent transmission lines. A complete analysis of the frequency dependence of the response of such a coupler is given. The amplifier is realized using the coupler and a pair of matched diodes terminating mutually isolated ports. To optimize the performance of this type of amplifier the design of the coupler is integrated with the design of the diode circuit. In doing so, account is taken of the frequency dependence of the hybrid junction, an aspect of the problem which has not been treated in the literature. As an example, an amplifier covering the VHF television channels is designed, and experimental results of a working model for a 50-ohm system are presented. The amplifier uses the periodicity of the directional coupler to provide two pass bands spanning Channels 2 to 6 (54 to 88 Mc) and Channels 7 to 12 (174 to 216 Mc), respectively. The two GE lN2939A tunnel diodes used for the amplifier provide a gain of 7.8 db ± 0.3 db for the lower band and 8.9 db ± 0.45 db for the upper band. The maximum input VSWR for the lower and upper bands are less than 2.3 and 3.2, respectively. The theoretical noise figure for a bias current of 0.7 ma is 3.79 db. It is found that the experimental results are in general agreement with the theory. Suggestions for improvement are given in cases where discrepancies do occur. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In the iterative method for producing maximally-flat response for the multicavity klystron amplifier, a choice must be made in allocating poles to cavities. In this thesis, a method is described for selecting the tuning pattern which will give flat response with maximum gain for a specific multicavity klystron. The iterative method for multicavity klystron amplifiers is extended, to tubes with up to six cavities. It is shown that the optimum tuning pattern has an appreciable advantage in gain over the alternative choices. The practice of allocating the highest-frequency pole to the penultimate cavity is justified, at least for relatively short tubes. Illustrative numerical tuning designs for four-, five- and six-cavity klystron amplifiers with different tuning patterns are given to verify the method. The restrictions of small-signal fundamental-mode theory apply throughout the thesis. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis describes the theoretical adjustment of the tuning of multicavity klystron amplifiers for prescribed frequency response. The method used is an iterative process developed at Stanford University in 1952. The purpose of the investigation was to test the applicability of the iterative method to the design of microwave amplifiers. The rational function representation of klystron amplifier response is described and it is shown that for physical realizability the zeros of transmission must be dependent on the poles of transmission. An iterative numerical method is developed for simultaneously fulfilling the prescribed response conditions and the physical realizability condition. Illustrative numerical designs of four- and five cavity klystron amplifier tuning are given which verify the method. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A multistable composite volt-ampere characteristic can be realized using a number of tunnel diodes. A maximum of 2ⁿ stable states can be obtained using n suitably chosen tunnel diodes connected in series. The main purpose of this study is to investigate the static and dynamic characteristics of such a circuit. Preliminary work deals with the switching behaviour of a single tunnel diode and the dependence of the switching time on the figure of merit and the current overdrive. This work serves as a background to the study of the multistate circuit. The study of the static characteristics of the composite device determines the conditions necessary for the generation of the required number of stable states. Additional conditions necessary to ensure proper operation are derived from the study of dynamic characteristics of a two tunnel diode multistate circuit. The dynamic conditions derived involve the tunnel diode capacitances and their ratio. The temperature dependence of the circuit is also investigated. Experimental results are presented showing an operating speed of 12.5 ns for a four state circuit using available tunnel diodes. The versatility of the composite characteristic obtained, and the inherent high speed of the tunnel diodes combine to make the multistate device useful in high-speed digital applications such as: binary addition, analog-to-digital conversion .and counting. These applications are discussed briefly. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The theory of the magnetic amplifier and other carrier amplifiers is put on a general mixer basis. The amplifiers are compared from this common basis and paths of further development indicated. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Experimental study was conducted to investigate fluidelastic instability in finned tube bundles with normal and parallel triangular arrays. Three arrays of each geometry type were studied experimentally: two arrays with serrated, helically wound finned tubes of different fin densities, and a bare tube array with the same base diameter as the finned tubes. The finned tubes under consideration were commercial finned tubes typically used in the fossil and process industries. For the purpose of the present investigation, the concept of "effective diameter" of a finned tube, as used to predict the vortex shedding, was used to compare the finned tube results with the existing bare tube world data and some theoretical predictions for fluidelastic instability. The finned tube arrays in this study have the same tube pitch and have been scaled to have the same mass ratio and tuned to have the same natural frequency. A low speed wind tunnel, Betz micro manometer and HP 35670a dynamic signal analyzer were employed to conduct the experiments. Experimental results for the triangular arrays show that the fin's structure strongly influences the fluidelastic stability of finned tube bundles and the fin pitch is demonstrated to reduce the difference in the fluidelastic instability between the tube arrangements as the fin density increases. The results also suggest that there might be an optimum fin pitch value at which the threshold reduced velocity for a finned tube array is much higher than the one for its corresponding bare tube array, due to the influence of fin geometry. In the appendix, an analytical model produces a new correlation of critical reduced velocity against mass damping parameter to predict the fluidelastic instability of tube bundles. Its predictions are in reasonable agreement with the experimental data. Since negative damping is one of the mechanisms of fluidelastic instability of a tube array, "Lift effect" was applied to explain the negative damping in an inviscid flow. An experiment is suggested to test the relationship between the pitch flow velocity and a tube velocity dependent "lift effect". Accordingly, two duct structure designs are suggested which may alleviate the negative damping by using the energy of oncoming flow to reduce the "lift effect" on the tubes. / Thesis / Master of Applied Science (MASc)

In order to effectively and efficiently hydroform new automotive components, the formability of new tubular steels must be evaluated. Standard forming limit diagrams have been used for decades to evaluate and predict the formability of sheet steel formed along linear strain paths. However, tube hydroforming can present a problem since the pre-bending stage used in many hydroforming operations causes multiple non-linear strain paths. This thesis has modified a formability test method that deforms small-scale sheet steel samples in a single plane. The sample geometries were designed such that the strain paths achieved at the center of the samples were very near the plane strain condition. The four steels chosen for this study were: a deep drawing quality (DDQ), a high strength low alloy (HSLA) and two dual phase steels (DP600 and DP780). The plane strain formability for each of the four steels was tested in both the rolling and transverse directions. Three objective criteria were employed to evaluate and directly compare the formability of the four steels tested: difference in strain, difference in strain rate and local necking. The DDQ steel showed the highest formability followed in order by the HSLA, DP600 and DP780 steels. The repeatability in determining the forming limit strains using the difference in strain, the difference in strain rate and the local necking criteria for a 95% confidence interval was ± 1.5%, ± 1.2% and ± 3.2% engineering strain, respectively. The forming limit data collected for this thesis has been compared to results from full-scale tube hydroforming operations and free expansion tube burst tests carried out by researchers at the University of Waterloo on the same four materials. It was found that local necking results could be used to predict failure of hydroformed HSLA steel tubes with low levels of end-feed. However, this same method could only predict the failure of hydroformed DP600 steel tubes at higher levels of end-feed. The three objective criteria were not found to be suitable for predicting failure of free expansion tube burst tests. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-09-27 15:00:35.873

Blue-flowered Conospermum are endemic to Western Australia, and show great potential as cut flowers. Propagation from cuttings or seed proved difficult, and root initiation in vitro is problematic. This thesis examines the floral biology of the species and the possibility of using somatic embryogenesis to overcome propagation problems. A survey of explant tissue types for C. eatoniae and C. caeruleum was carried out to identify tissue that could be induced into embryogenic pathways. Vegetative, semi-floral and floral buds were initiated into culture from February to June, but were found unsuitable for embryogenesis, producing shoots, callus or dying in culture. Leaves from in vitro leaf cultures formed callus in the presence of 2,4-D and BAP, but were unable to differentiate into embryos in the presence of a variety of growth regulator combinations and concentrations. Immature zygotes died in culture. Direct embryogenesis and/or embryogenic callus was observed on mature zygotes of the species C. caeruleum, C. spectabile, C. dorrienii and C. brownii, and somatic embryos were maintained in culture for up to 18 months for C. caeruleum. Maturation and germination of somatic embryos proved difficult; treatments of cold, ABA, desiccation or mannitol did not induce maturation. It appears that developmental pathways in Conospermum are well defined and are difficult to alter in vitro. It was concluded that somatic embryogenesis has limited commercial potential in these species. Conospermum species have an active pollination mechanism where the style is held in a state of tension when the flower opens. When pressure is applied at the base of the style by an insect, the style flicks downwards, striking the insect pollinator and releasing pollen from the anther in a single dusty mass. However, the breeding systems of blue-flowered Conospermum have not previously been well explored. Flowers on a C. eatoniae inflorescence opened from the basal end upwards acropetally, with the terminal two or three buds never opening. Fruit and seed set occurred only from the basal one to three buds. Isolation of C. eatoniae and C. amoenum flowers showed they were unable to self-pollinate in the absence of insect pollinators. Experiments to determine the timing of the peak of stigmatic receptiveness were inconclusive. Pollen germinated and penetrated the stigma 0 ¡V 6 days after anther dehiscence. Pollen loads on the stigma did not relate to the number of pollen tubes observed down the style. Controlled pollinations of cultivated C. eatoniae at a field station using self and cross pollen, revealed compatibility with a range of pollen genotypes, as pollen tubes were observed extending down the style. However, late-acting incompatibility could not be ruled out as controlled crosses failed to set any seed as flowers were shed from the bush. DNA analysis of open pollinated C. eatoniae seed progeny from two plants from a field station and two plants in natural bushland revealed very different pollination habits. Plants from the field station showed no outcrossing, with progeny closely resembling the maternal parent, whereas plants from the wild population showed outcrossing with several different paternal parents. These results suggest self-pollinated seed can be reliably obtained in a plantation situation using stands of ramets of the same clone. Alternatively, assuming that the required insect pollinators are present in a cultivated stand, it should be possible to obtain cross pollinated seed by surrounding the maternal plant with the desired paternal parent. Unusual pollen behaviour was observed for many blue-flowered species, a white-flowered species of Conospermum, and close relative, Synaphea petiolaris. Up to three pollen tubes emerged from the triporate pollen in vitro, and at rates of up to 55 ƒÝms-1. This rate was maintained for only 2 s but is greater than 20 times faster than reported in the literature for any species, in vitro or in vivo. Pollen with multiple tubes was also observed on the stigma in vivo in C. amoenum flowers. Changing the osmotic pressure of the germination medium by altering sucrose concentration influenced the number of tubes to emerge from the pollen grain; generally the number of tubes decreased as sucrose increased. However, the rate of tube growth was unaffected. The addition of calcium channel blockers to the germination medium had no effect on Conospermum growth rate, nor did they eliminate pulses of tube growth. Observation of Conospermum pollen ultrastructure revealed similarities to Gramineae pollen. The tube cytoplasm was packed with vesicles filled with material of similar electron density to the cell wall. Few golgi were identified, and the apical end of the tube contained these vesicles, smaller secretory vesicles and mitochondria. This is atypical of the tip, which is normally free of large vesicles. Distinct zones in the cytoplasm were not identified, which is similar to Gramineae. Like the grasses, Conospermum appears to pre-manufacture cell wall material and store it in vesicles ready for rapid germination and extension. A biological function of multiple pollen tube emergence with such rapid growth was not elucidated. This research has shown Conospermum to be a complex and very interesting genus. Further investigation into the remarkable growth of multiple pollen tubes would enhance our knowledge of the biological processes involved in tube growth and the process of fast wall formation. The potential benefits to the cut flower industry of commercialising some of these species warrants further effort to find an efficient method of propagation. Introduction into horticulture may be the only means by which these threatened species will survive.