A new special case computer simulation to model the non-linear, three dimensional dynamic equations of motion of a five degree of freedom point contact joint has been developed and the functionality has been validated with data collected from a physical model. A system physically realistic to model was designed with sphere in sphere contact. A small outboard body articulates within a larger inboard spherical cut out body and springs help provide stability to the system by attaching the outboard body to the ground. The outboard body can move relative to the inboard body in both a rolling and sliding manner. The dynamic equations of motion were determined using Kane’s formulation and a numerical solution was attained through the implementation of a fourth-fifth order, variable time step, Runge-Kutta integrator. The positions of four markers, located on the outboard body of the system, were predicted in ground fixed coordinates by the solution routine. A physical model of the system was constructed and position locations of four markers located on the outboard body were captured by an Optotrak 3020 motion tracking system. Both static and dynamic experimental trials were performed and compared to the simulation. For one test case, the experimental data frequency of oscillation was found to be ωe = 2.33 Hz and the simulation frequency was found to be ωs = 2.37 Hz. Several sources for the discrepancies include viscous damping, a possible additional forcing function caused by lead wire sway, and neglecting the mass of the system’s springs. Coulomb damping was included in the simulation. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-10-30 16:12:57.843

Applications such as video and audio streaming, online gaming, video conferencing, Voice over IP (VoIP) and File Transfer Protocol (FTP) demand a wide range of QoS requirements such as bandwidth and delay. Existing wireless technologies that can satisfy the requirements of heterogeneous traffic are very costly to deploy in rural areas and “last mile” access. Worldwide Interoperability for Microwave Access (WiMAX) provides an affordable alternative for wireless broadband access supporting a multiplicity of applications. The IEEE 802.16 standard provides specification for the Medium Access Control (MAC) and Physical (PHY) layers for WiMAX. A critical part of the MAC layer specification is scheduling, which resolves contention for bandwidth and determines the transmission order of users. It is imperative for a scheduling algorithm to have a multi-dimensional objective of satisfying QoS requirements of the users, maximizing system utilization and ensuring fairness among the users. In this thesis, we categorize and study various scheduling algorithms for the uplink traffic in WiMAX in view of these objectives. The algorithms are studied under different mixes of traffic and for various characteristics of the IEEE 802.16 MAC layer such as uplink burst preamble, frame length, bandwidth request mechanisms etc. Simulation results indicate that legacy algorithms are not suitable for the multi-class traffic in WiMAX as they do not explicitly incorporate the WiMAX QoS parameters. We provide recommendations for enhancing existing scheduling schemes in WiMAX, and shed light on some of the open issues that need to be addressed. / Thesis (Master, Computing) -- Queen's University, 2007-12-29 18:21:21.521

Rangeomorphs are a distinct group of millimeter- to meter-scale soft-bodied macrofossils that are restricted to the latter half of the late Neoproterozoic Ediacaran Period (635Ma- 542Ma). These fossils represent an extinct higher level taxon characterized by a modular construction based on a single architectural unit: the centimeter-scale, chevron-shaped rangeomorph element which displays several orders of self-similar branching. These elements could be arranged in a variety of different ways, constituting the wide array of gross morphologies found within the Group Rangeomorpha. The largest and most diverse assemblage of rangeomorph fossils in the world is found at Mistaken Point, on the Avalon Peninsula of Newfoundland, Canada, where these organisms are preserved within their original, in situ paleocommunities. Multibranched rangeomorphs are typified by bush-, comb- and network-shaped fossils which display multiple rangeomorph-bearing structures attached to an untethered basal stolon or central attachment point. Multibranched, comb-shaped rangeomorphs are endemic to Mistaken Point, and are represented by fossils displaying multiple parallel struts emerging along one side of an elongate, curved pedicle rod. Morphological and taphonomic evidence suggests that, in life, this organism had two rows of struts, each bearing a rangeomorph frondlet, arranged in an alternating pattern along the curved, tubular pedicle rod. Biometric analyses imply that the struts were added to both ends of the pedicle rod throughout the organism’s lifetime, with later inflation of the rangeomorph frondlets. Each comb-shaped rangeomorph locality likely represents a different age cohort within the organism’s lifecycle, providing rare evidence for spatfall reproduction in Ediacarans, which is similar to that found in modern macrobenthic organisms with pelagic larvae. Network-shaped multibranched rangeomorphs, represented by symmetrical to asymmetrical net-like fossils, are also endemic to Mistaken Point. This genus is reconstructed as having a symmetrical arrangement of flexible, rangeomorph-bearing leaflets that were, in part, neutrally buoyant with respect to the seawater. This flexible leaflet structure is unique, and shared only with a rare, previously undescribed, Ediacaran frond-like organism. It is suggested that the enigmatic leaflet structures shared by these two morphologically distinct taxa represent a new type of rangeomorph branching architecture, and therefore constitute a new type of rangeomorph. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2008-07-25 11:01:43.469

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No description available.

No description available.

There have been major changes to the farming practices across Canterbury in the past 50 years, with the biggest changes seen in the previous two decades. These changes in farming practices, namely dairy farming and irrigation, have lead to declining water quality in the region. The changes that have been experienced on the Canterbury plains are now being seen in the hill and high country settings, such as the Hakataramea Valley. This study found that the waterways in the Hakataramea Valley are susceptible to nutrient enrichment following a rainfall event that caused soil runoff. Wind erosion also occurrs in the valley and was believed to be the major source of nutrient transport in the waterways, however, this was proven to be not as significant as soil runoff. The valley showed a range in water quality, with the river generally being of a higher quality than the tributaries. One tributary in particular stood out as being lower in quality than the others, this was Rocky Point stream. It was identified that the tributary catchments that had extensive farming systems and no irrigation present (Grampians Stream and Rocky Point Stream) were of a lower quality than the tributary that had irrigation (Padkins Stream). This was due to the fact that waterways in this catchment were fenced, and on farm stockwater systems were in place, stopping stock from accessing the waterway. The OVERSEER modelling of the future scenarios presented showed that if the agriculture in the valley was to continue to develop and intensify, the water quality would decline. If the valley became completely irrigated this decline could potentially be large enough to result in a level that would become unsafe for recreational use and human and animal consumption. The future of the Hakataramea Valley and its waterways depends on improved management processes that focus on specific areas of the catchment and the catchment as a whole.

The work explains how the dynamics of the release of water vapors from flux during the Control Atmosphere Brazing influences the process conditions important for the quality of the brazed product. The process involves sequential events such as continuous ramp-up heating, flux and filler melting, reactive flow, isothermal dwell and rapid quench solidification performed under the controlled atmosphere. During this complex process effluents are released. Some effluents are detrimental for the product quality (water vapor) and some are harmful for the environment (HF). We selected to study water vapor emissions with an objective to quantify these emissions and to consider their influence on the manufacturing process. Experiments were conducted using different fluxes. Findings are presented to compare the vapors released in each case. The objective is not necessarily to develop a metric for sustainability, but to understand the kinetics of an effluent release. A simple predictive model has been devised to approximate experimental data behavior. The data from the TGA analysis obtained from other sources, and the dew point temperature history from the controlled atmosphere brazing experiments performed in course of this work, have been used for the purpose of comparison and analysis.

Ce mémoire présente des mesures de conductivité thermique sur les supraconducteurs YBCO et Tl-2201 afin de statuer sur la présence possible d'un point critique quantique (QCP) dans le diagramme de phase de cuprates. Ce point critique quantique serait à l'origine de la reconstruction de la surface de Fermi, d'un large cylindre de trous en de petites poches de trous et d'électrons. La conductivité thermique dans le régime T [arrow right] 0 permet d'extraire une quantité purement électronique liée aux vitesses de Fermi et du gap, au noeud. Une discontinuité dans cette quantité pourrait signaler la traversée du dopage critique qui reconstruit la surface de Fermi. Plusieurs sondes expérimentales distinguent une transition de phase ou un crossover à T * à température finie. D'autres sondes mettent en évidence une transition de phase sous l'effet d'un champ magnétique. La présence ou non de cet ordre, à température et champ magnétique nul questionne la communauté depuis plusieurs années. Dans cette étude, nous détectons une variation brusque de ?0 /T à p = 0.18 dans YBCO et à p = 0.20 dans Tl-2201. Ces sauts sont interprétés comme un signe de la transition à température nulle et sont en faveur d'un QCP. Le manque de données d'un même matériau à ces dopages ne permet pas de valider hors de tout doute l'existence d'un point critique quantique. Le modèle théorique YRZ décrit aussi bien les données de conductivité thermique. Des pistes de travaux expérimentaux à poursuivre sont proposées pour déterminer la présence ou non du QCP de façon franche.

No description available.