Phase control system concepts and simulations

A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier

Feasibility of Fused Deposition of Ceramics with Zirconia and Acrylic Binder

Processing of ceramics has always been difficult due to how hard and brittle the material is. Fused Deposition of Ceramics (FDC) is a method of additive manufacturing which allows ceramic parts to be built layer by layer, abetting more complex geometries and avoiding the potential to fracture seen with processes such as grinding and milling. In the process of FDC, a polymeric binder system is mixed with ceramic powder for the printing of the part and then burned out to leave a fully ceramic part. This experiment investigates a new combination of materials, zirconia and acrylic binder, optimizing the process of making the material into a filament conducive to the printer system and then performing trials with the filament in the printer to assess its feasibility. Statistical analysis was used to determine optimal parameter levels using response surface methodology to pinpoint the material composition and temperature yielding the highest quality filament. It was discovered that although the mixture had adequate melting characteristics to be liquefied and printed into a part, the binder system did not provide the stiffness required to act as a piston to be fed through the printer head. Further studies should be completed continuing the investigation of zirconia and acrylic binder, but with added components to increase strength and rigidity of the filament

Interactive 3-D Visualization: A tool for seafloor navigation, exploration, and engineering

Recent years have seen remarkable advances in sonar technology, positioning capabilities, and computer processing power that have revolutionized the way we image the seafloor. The massive amounts of data produced by these systems present many challenges but also offer tremendous opportunities in terms of visualization and analysis. We have developed a suite of interactive 3-D visualization and exploration tools specifically designed to facilitate the interpretation and analysis of very large (10\u27s to 100\u27s of megabytes), complex, multi-component spatial data sets. If properly georeferenced and treated, these complex data sets can be presented in a natural and intuitive manner that allows the integration of multiple components each at their inherent level of resolution and without compromising the quantitative nature of the data. Artificial sun-illumination, shading, and 3-D rendering can be used with digital bathymetric data (DTM\u27s) to form natural looking and easily interpretable, yet quantitative, landscapes. Color can be used to represent depth or other parameters (like backscatter or sediment properties) which can be draped over the DTM, or high resolution imagery can be texture mapped on bathymetric data. When combined with interactive analytical tools, this environment has facilitated the use of multibeam sonar and other data sets in a range of geologic, environmental, fisheries, and engineering applications

Conceptualizing age-friendly communities for Saskatoon's Chinese-Canadian older adults

With the demographic composition of Canadian cities in constant motion in terms of both the age and ethnicity of their residents, urban geographers must create frameworks of inclusion that recognize the intersecting needs of these postmodern landscapes. While the social and environmental necessities of older adults in urban centres are increasingly met through the production and maintenance of age-friendly communities, urban geographers must question whether these models are accessible and beneficial to older adult members of the visible- minority population. The Chinese-Canadian community, which has faced extensive discrimination and racism across history and within current social and institutional platforms, hosts an older adult cohort at particular risk of exclusion from health and social services, housing, economic stability and social inclusion. The intent of this research is to determine whether age-friendly community initiatives are indeed accessible to Chinese-Canadian older adults, while helping to re-conceptualize more ethnically-inclusive age-friendly paradigms. Through a series of semi-structured interviews within Saskatoon’s Chinese-Canadian community, this work highlights sources of spatial, social and generational exclusion, recognizes the positive attributes of culturally homogenous housing and recreational organizations, and identifies barriers to the effectiveness of existing age-friendly community models surrounding both transportation and healthcare needs. Following a thorough examination of Saskatoon’s Chinese-Canadian community, this research theorizes new frameworks that enable more inclusive and equitable approaches, highlighting the importance of cultural and linguistic inclusivity in existing age-related programs, the benefits of institutional recognition and support of culturally-catered organizations, and the need for broader social and historic inclusion of Chinese-Canadian older adults within the Saskatoon community. In doing so, this research not only informs the manner whereby age-friendly communities are conceptualized, but helps to bring the needs of Saskatoon’s Chinese-Canadian demographic to the forefront of community development practice and application

Radar and satellite characterization of the ionosphere under strong electric field conditions

It is now well established that strong electric fields can distort high-latitude ion velocity distributions to the point that this affects Incoherent Scatter Radar (ISR) observations, and therefore the ion and electron temperatures inferred through those observations. Until now, studies of this topic have focused on first order, semi-empirical ion velocity distribution descriptions. However, a precise description has been lacking, notably along directions parallel or near-parallel to the magnetic field. To remedy these shortcomings and provide the best possible tools to analyze ISR observations, this thesis uses a state-of-the-art Monte-Carlo (MC) simulation to retrieve accurate ion velocity distributions for any electric field, ion-neutral particle interaction, and direction relative to the magnetic field. Through these improvements, a number of important points have been made, such as: 1) for the most part simulated NO+ ISR observations can be modeled using Maxwellian velocity distributions having the same line-of-sight ion temperature as the simulated MC distribution, 2) although simulated O+ ISR observations parallel to the magnetic field are similar to those produced from Maxwellian velocity distributions they reflect an erroneous increase in electron temperature due to a wide O+ velocity distribution, and 3) signatures of toroidal ion velocity distributions in IS spectra are possibly the easiest to identify near 20 degrees with respect to the magnetic field. Based on these results, accurate distorted ion velocity distributions are currently being incorporated into IS spectral fitting routines. In the logical next step, this thesis turns to radar observations to characterize the ion temperature anisotropy, which is particularly important for Joule heating studies. Using ISR observations from a particularly strong heating event reported by Clauer et al. (2016), it is found that the O+-O collision cross-section from Knof et al. (1964) represents the anisotropy of the ionosphere fairly accurately, but still suggests the ionosphere to be slightly more anisotropic than expected. Knowing this allows for the preliminary determination of the effective electric field (the electric field in the neutral frame of reference). To obtain the electric field vector at a given latitude and longitude this thesis has explored a novel technique that employs multi-altitude measurements. This method combined with a knowledge of the effective electric field from the ion temperature studies opens up the possibility of a determination of the neutral wind in future work. Finally, to study the impact electric field strength has on Swarm satellites observations and on the upper ionosphere in general, a time-dependent gyro-kinetic O+ model of the motion of ions above a discontinuous boundary between fully collisional and collisionless plasmas has been revisited. This upgraded model uses descriptions of the ion velocity distribution provided by the MC simulation for the boundary velocity distribution as a function of electric field. As well, it incorporates a variable boundary plasma density and can describe any temporal variation of the ion velocity distribution at the boundary without complications. The results agree with the observations of highly distorted ion velocity distributions at high altitudes, as well as explain heretofore unpredictable anisotropic ion temperatures, attributing them to changing boundary conditions propagating upwards along a given flux tube, away from strongly-collisional regions