Constraints on Off-Axis X-Ray Emission from Beamed GRBs

We calculate the prompt x-ray emission as a function of viewing angle for beamed Gamma-Ray Burst (GRB) sources. Prompt x-rays are inevitable due to the less highly blueshifted photons emitted at angles greater than 1/gamma relative to the beam symmetry axis, where gamma is the expansion Lorentz factor. The observed flux depends on the combinations (gamma Delta theta) and (gamma theta_v), where (Delta theta) is the beaming angle and theta_v is the viewing angle. We use the observed source counts of gamma-ray-selected GRBs to predict the minimum detection rate of prompt x-ray bursts as a function of limiting sensitivity. We compare our predictions with the results from the Ariel V catalog of fast x-ray transients, and find that Ariel's sensitivity is not great enough to place significant constraints on gamma and (Delta theta). We estimate that a detector with fluence limit ~10^{-7} erg/cm^2 in the 2-10 keV channel will be necessary to distinguish between geometries. Because the x-ray emission is simultaneous with the GRB emission, our predicted constraints do not involve any model assumptions about the emission physics but simply follow from special-relativistic considerations.Comment: Submitted to Ap

The anglican church of Canada and the Indian residential schools: a meaning-centred analysis of the long road to apology

The Canadian residential school system, which operated from the 1880s until the 1970s, was a church-state enterprise designed to assimilate Aboriginal children into Euro-Canadian culture and was characterized by poor sanitation and widespread abuse. Recently, it has been the object of the most significant and most successful struggle for redress in Canadian history. However, for most of its long history, the many failings of the residential school system went unacknowledged by the organizations formerly involved in its operation. In this thesis, I seek to explain why. In doing so, I provide a framework for further study on the residential schools and on comparable cases. To resolve my question, I conduct a comparative historical analysis of the Anglican Church of Canada, which was formerly an important partner in the operation of the residential schools. My data is drawn from a wide range of archival material. My analysis is framed by a meaningcentred approach to social behaviour referred to as the Strong Program. In sum, I argue that the initial meaning of the school system as a sacred enterprise hindered acknowledgement of its failings. For the church to acknowledge the failings of the residential schools, such a meaning needed to be replaced with a new meaning emphasizing the tragic consequences of the school system. This could only occur once the balance of social power had shifted away from the defenders of the sacred meaning and towards its detractors

Orbital Optimization of Interplanetary Trajectories with Environmental Perturbations

For a detailed analysis of orbital optimization, it is desired to incorporate a spacecraft environment model in order to have maximum confidence that the analysis will produce an accurate trajectory. Such a model requires the addition of orbital perturbations, or small forces acting on the spacecraft throughout its trajectory that can eventually accumulate in large distances over time. The optimization method that this thesis is concerned with is STOpS (Spacecraft Trajectory Optimization Suite), a Matlab optimizer created by Timothy J. Fitzgerald that utilizes an Island Model Paradigm with five different optimization algorithms. STOpS was originally built to model trajectories with the two body equations of motion. A Lambert\u27s method was utilized to link the spacecraft trajectory from planet to planet, and a flyby section was created for the hyperbolic gravity assist trajectories. A cost function was then used to evaluate the best combination of Delta V, time of flight, synodcity, flyby altitude, and heliocentric energy. This work is primarily concerned with adding the dynamics created by perturbations into Lambert\u27s problem as well as the gravity assist trajectories. The improved analysis creates a more robust solution for dealing with optimized interplanetary trajectories. Two proven trajectories will be focused on for the main analysis of this thesis which are the trajectories taken by Voyager 2 in the tour of the solar system as well as Cassini\u27s mission to Saturn. When perturbations were added to the analysis of these missions, STOpS was able to find trajectories which met both Delta V and time of flight requirements for each mission. For the optimization of each of these missions the key dates of departure, flyby, and arrival at all the planets varied by no more than one year from the true trajectories of Voyager 2 and Cassini

Multiculturalism and identity in Canada : a case-study of Ukrainian-Canadians

The thesis provides a political analysis of a position paper on government programming recently adopted by the Ukrainian Canadian Congress (UCC) – a national ethno-cultural organisation that ostensibly represents over one million Canadians of Ukrainian heritage and a historically important player in the development of multiculturalism in Canada. The impetus for such an analysis is to explore whether there are alternative policy directions available to the UCC that could satisfy its mandate developing and enhancing the Ukrainian-Canadian community while taking into account the reality that Ukrainian-Canadians culturally resemble more and more the broader Canadian society. In a wide-ranging analysis that criticizes both, official Canadian multiculturalism – for falling short in meeting its commitment to cultural pluralism – and the UCC – for upholding a position that relies on a static or retrograde version of culture, the thesis makes the case for a multiculturalism that can recognize cultural differences while allowing for change. The thesis is significant because it asks relevant questions concerning how multiculturalism in Canada takes into account an increasingly heterogeneous citizenship characterized by cultural change. In this regard, the thesis is of particular importance to Canadians who claim a multiplicity of cultures rather than a single ethnicity and yet still express a desire to be included in the discourse on Canadian national identity

How nationalism can be a force for good in the struggle against Covid-19

Recent years have seen a resurgence of nationalist sentiment across many countries in the West and beyond, and the ideology is now shaping much of the response to the worldwide Covid-19 pandemic. Robert Schertzer and Eric Taylor Woods write that this doesn’t have to be a bad thing – if we can tap into the liberal, inclusive side of nationalism as exemplified by past national projects like the New Deal

Integrated Thermal Energy Storage System For Air-conditioners With Phase-Change Composites

Thermal energy storage (TES) is a promising solution to store and dispatch energy and shave peak electric load, reducing the operational cost of HVAC systems. We present results of a TES system using phase-change materials (PCM) integrated with an air conditioner. The proposed system uses an organic PCM (tetradecane) encapsulated within compressed expanded natural graphite foams referred to as phase-change composite. The graphite foam encapsulates the PCM eliminating the need for expensive storage vessels, reduces installation costs, and provides higher thermal conductivity that can lead to faster charge/discharge rates. Two serpentines, multi-pass circuits, operating as a heat source and a sink, exchange heat to and from the phase-change composite. These two circuits are embedded in multiple slabs of this material. The “charge” circuit contains the refrigerant that is directly coupled to a vapor compression system, and the “discharge” circuit removes heat from an airstream and releases it into the PCM composite through a water-glycol liquid coupling. This configuration allows for multiple modes of operation depending on the state of charge of the thermal energy storage module, the building air-conditioning load, and the current electricity and demand charges. This flexible operation allows variable air volume capacity control without the need to have a variable capacity refrigeration system. We developed a 21 kW-hr (6 RT-hr) prototype TES system coupled with a commercial air-conditioner to characterize the component-and system-level performance

Creating, Innovating, and Imagining

The most difficult task facing educators in the United States is expanding the focus beyond intervention and prevention programs to conceptualizing and implementing empowerment processes for males. Increasing reading and math scores is not good enough. This session focuses on a systematic approach to addressing the unique needs of males and their families using strategies directed at closing the achievement gap. Moreover, it will provide a framework of understanding to assist in engaging educators in discussions and help all stakeholders share a common purpose for the growth, development, and achievement of males