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Experimental tests on a transonic annular rig are time-consuming and expensive, so it is desirable to use experimental results to validate a computational model which can then be used to extract much more information. The purpose of this work is to create a numerical model that can be used to simulate many different scenarios and then to apply these results to experimental data.; In the modern world, gas turbines are widely used in aircraft propulsion and electricity generation. These applications represent a massive use of energy worldwide, so even a very small increase in efficiency would have a significant beneficial economic and environmental impact. There are many ways to optimize the operation of a gas turbine, but a fundamental approach is to increase the turbine inlet temperature to increase the basic thermodynamic efficiency of the turbine. However, these temperatures are already well above the melting temperature of the components. A primary cooling methodology, called film cooling, creates a blanket of cool air over the surface and is an effective way to help protect these components from the hot mainstream gasses. This paper focuses on the effect of the film holes upstream of the first row of blades in the turbine because this is the section that experiences the highest thermal stresses. Many factors can determine the effectiveness of the film cooling, so a complete understanding can lead to effective results with the minimum flow rate of coolant air. Many studies have been published on the subject of film cooling, but because of the difficulty and expense of simulating turbine realistic conditions, many authors introduce vast simplifications such as low speed conditions or linear cascades. These simplifications do not adequately represent the behavior of a turbine and therefore their results are of limited use. This study attempts to eliminate many of those simplifications. The test rig used in this research is based on the NASA-GE E³ design, which stands for Energy Efficient Engine. It was introduced into the public domain to provide an advanced platform from which open-literature research could be performed.

Current trends in spacecraft are leading to smaller, more inexpensive options whenever possible. This shift has been primarily pursued for the opportunity to open a new frontier for technologies with a small financial obligation. Limited power, processing, pointing, and communication capabilities are all common issues which must be considered when miniaturizing systems and implementing low-cost components. This thesis addresses some of these concerns by applying two methods, in attitude estimation and control. Additionally, these methods are not restricted to only small, inexpensive satellites, but offer a benefit to large-scale spacecraft as well. First, star cameras are examined for the tendency to generate streaked star images during maneuvers. This issue also comes into play when pointing capabilities and camera hardware quality are low, as is often the case in small, budget-constrained spacecraft. When pointing capabilities are low, small residual velocities can cause movement of the stars in the focal plane during an exposure, causing them to streak across the image. Additionally, if the camera quality is low, longer exposures may be required to gather sufficient light from a star, further contributing to streaking. Rather than improving the pointing or hardware directly, an algorithm is presented to retrieve and utilize the endpoints of streaked stars to provide feedback where traditional methods do not. This allows precise attitude and angular rate estimates to be derived from an image which, with traditional methods, would return large attitude and rate error. Simulation results are presented which demonstrate endpoint error of approximately half a pixel and rate estimates within 2% of the true angular velocity. Three methods are also considered to remove overlapping star streaks and resident space objects from images to improve performance of both attitude and rate estimates. Results from a large-scale Monte Carlo simulation are presented in order to characterize the performance of the method. iii Additionally, a rapid optimal attitude guidance method is experimentally validated in a groundbased, pico-scale satellite test bed. Fast slewing performance is demonstrated for an incremental step maneuver with low average power consumption. Though the focus of this thesis is primarily on increasing the capabilities of small, inexpensive spacecraft, the methods discussed have the potential to increase the capabilities of current and future large-scale missions as well.

A trend in polarization as predicted by theoretical models was validated, and atmospheric dust grain sizes and projected rotational velocities for these objects were estimated. Comprehensive studies of UDs are proving to be crucial not only in our understanding of UDs but also for star and planet formation as brown dwarfs represent their lower and upper mass boundaries, respectively. Brown dwarfs (BD) were mere theoretical astrophysical objects for more than three decades (Kumar (1962)) till their first observational detection in 1995 (Rebolo et al. (1995), Nakajima et al. (1995)). These objects are intermediate in mass between stars and planets. Since their observational discovery these objects have been studied thoroughly and holistically.Various methods for searching and characterizing these objects in different regions of the sky have been put forward and tested with great success. Theoretical models describing their physical, atmospheric and chemical processes and properties have been proposed and have been validated with a large number of observational results. The work presented in this dissertation is a compilation of synoptic studies of ultracool dwarfs(UDs)¹. [Footnote 1:]. [bullet] A search for wide binaries around solar type stars in upper scorpio OB association (Upper Sco) do indicate (the survey is not yet complete) a deficit of BD binaries at these large separations ([less than] 5AU). [bullet] Twenty six new UDs were discovered at low galactic latitudes in our survey from archival data and a novel technique using reduced proper motion. [bullet] Six field UDs were discovered by spectroscopic follow-up of the candidates selected from a deep survey. [bullet] Optical interferometry was used to independently determine the orbit of the companion of HD33636 which was initially determined using Hubble Space Telescope(HST)astrometry and radial velocity found. Some inconsistency in the HST determined orbit and mass. [bullet] Optical linear polarization in UDs was used to investigate the dust propertied in their atmospheres. Footnote 1: We use the term "ultracool dwarfs" as the mass of most of the objects mentioned is unknown, which is required to classify an object as a brown dwarf. We define objects later than M7 as ultra cool dwarfs.

This thesis investigates the capabilities of STAR-CCM+, a Computational Fluid Dynamics (CFD) software owned by Siemens, in predicting hypersonic heat transfer loads on forward-facing surfaces. Results show that STAR-CCM+ predicted peak heat transfer loads within +/- 20% of experimental data on the leading edge of a delta wing design from the X-20 Dyna-Soar program with 73o of sweep. Steady-state laminar simulations were run as replications of wind tunnel tests documented in NASA CR-535, a NASA technical report that measured and studied the hypersonic pressure and heat transfer loads on preliminary X- 20 wing designs across a wide range of Reynolds numbers and Mach numbers in different wind tunnel and shock tunnel facilities. One of the Mach 8.08 test cases that was run at NASA Arnold Engineering Development Center Wind Tunnel B was selected as the case of comparison for this thesis, which was designated as test AD462M-1 in the original report. The CFD simulations assumed an ideal gas in laminar flow with temperature-dependent viscosity, thermal conductivity, and isobaric specific heat across an angle of attack range from 0o to 30o. A separate CFD study of heat transfer loads of a hemisphere-cylinder at Mach 6.74 was used as a simpler and less computationally-expensive validation case compared against wind tunnel data from NASA Langley Research Center to help select the appropriate CFD solver and mesh settings for this thesis. For the hemisphere-cylinder, the heat transfer load at the stagnation point was overpredicted in STAR-CCM+ by 21.8%. Peak heat transfer loads on the delta wing leading edge were all within +/- 20% of the wind tunnel data, which was published for angles of attack between 15o to 30o. A more adverse heat transfer gradient along the leading edge of the delta wing was also observed in the direction from the front of the wing to the outer wing tip when compared to wind tunnel data. The pressure loads on the delta wing leading edge in CFD were within +/-10% of wind tunnel measurements.

This dissertation examines social mobility as treated in stage comedies and litigation records circa 1603-1625. It argues that, in a historical context where rising in the world often awakened disapproval, stage representations of advantageous marriages negotiated cultural debates concerning socioeconomic change, political hierarchy, and individual aspirations. To understand the diverse meanings of social advancement, this study traces the discursive and narrative resemblances between two sets of texts: nearly two hundred Star Chamber cases that contested marital status incompatibility, and plays by Middleton, Jonson, Chapman, and their peers that dramatize intense competitions for marriages that could elevate characters in wealth and prestige. Pierre Bourdieu provides methods for approaching the multi-dimensional early modern social field with its many forms of status, and Frederic Jameson offers ways to consider the relation of fictional narratives to social and ideological problems. Using these theorists to align the two sets of texts, this dissertation reveals how London's theaters offered complex fantasies of achievement that balanced individual ambition against prevailing assumptions about gender, status, and social order. The Introduction traces relevant historical contexts, while Chapter One outlines the polyphonic features of the texts under investigation and culminates in an analysis of George Chapman's use of multiple temporal schemes in The Widow's Tears to represent a fantasy marriage as both an upstart's rise and a dynastic renewal. Chapter Two examines legal records to reveal how victims of alleged courtship frauds evoked a broad cultural script that represented social exogamy as a threat to the ruling elite. Chapters Three and Four focus on masculinity, arguing that both male defendants and playwrights like Thomas Middleton and Lording Barry responded to the cultural contradictions of social mobility by privileging alternative metrics of masculine worth and alternative trajectories of advancement. Chapter Five shows how female defendants positively rearticulated available negative stereotypes about women, especially servants, marrying up; in similar fashion Ben Jonson's The New Inn portrays a maidservant's engagement to an aristocrat as a triumph of merit. Finally, the Appendix examines one extensive case in which dozens of witnesses variously interpreted the scandalous elopement--or kidnapping--of a rich London woman. / 2019-08-01T00:00:00Z

Globular clusters are not simple stellar populations. Practically all globular clusters show multiple populations (MPs), where at the same metallicity [Fe/H], approximately half of their stars are enriched by the products of high-temperature hydrogen burning relative to the rest that show field-like abundances. The source of enrichment for forming the enriched population is an unresolved problem. Interacting massive binaries are an underexplored proposed source of enrichment. Many assessments of the theory are based on only one modelled binary. We simulate a suite of metal-intermediate, [Fe/H]=-1.44, interacting binaries with initial primary masses of 10 to 40 solar masses, with mass ratios ranging from 0.15 to 0.9, over periods ranging from about 2 to 700 days using MESA. Our simulations show that binaries at higher masses, higher mass ratios, and near our upper period limit tend to be the most enriching with ejecta showing HeNaCNOAlMg variations consistent with hot-H burning. Some binaries do not eject material, suggesting binary mass loss can contribute to the dilution of enrichment. As a realistic population, binaries within our parameter space eject about ten times as much mass as they would as single stars. Ejection occurs on timescales of about 11 Myr, consistent with observed and theoretical limits on the age spreads for MPs. Our systems are rare, making them more suited to explaining the stochastic nature of MPs but not the large fraction of enriched stars. Spreads in He, N, Na, C, and Al for our ejecta could reasonably explain the observed spreads in clusters. Reduced variation in O and Mg suggests more massive binaries should be investigated. A multi-scale approach to cluster formation with multiple types of enrichment sources is a necessary next step for validating MP formation scenarios. / Thesis / Master of Science (MSc) / The majority of stars form in star clusters. Globular clusters are the oldest and most massive type of star cluster. Formerly thought to be made of stars of the same age and chemical composition, nearly all observed globular clusters are now known to host multiple populations. About half of their stars form from similar material as isolated stars. The other half show signs of enrichment. How enriched stars get their enriching material is an open problem in cluster formation. Pairs of stars orbiting each other as binaries were proposed to eject the material needed to form these stars. We model 408 binaries to find that some systems eject large amounts of enrichment, especially when the stars are more massive. The rarity of these systems suggests binaries can explain the variations seen in multiple populations between clusters but cannot fully explain the large fraction of enriched stars seen.

We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the δ Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of ≈ 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5–25 Å is confirmed, with a maximum amplitude of about ±15% within a single ≈ 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S xv, Si xiii, and Ne ix. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at ϕ = 0.0 when the secondary δ Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind–wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability. Based on data from the Chandra X-ray Observatory and the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star ξ1 CMa. This star is a variable of β Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism.

We report the discovery of weak yet hard X-ray emission from the Wolf-Rayet (WR) star WR 142 with the XMM-Newton X-ray telescope. Being of spectral subtype WO2, WR 142 is a massive star in a very advanced evolutionary stage shortly before its explosion as a supernova or gamma-ray burst. This is the first detection of X-ray emission from a WO-type star. We rule out any serendipitous X-ray sources within approximate to 1 '' of WR 142. WR 142 has an X-ray luminosity of L(X) approximate to 7 x 10(30) erg s(-1), which constitutes only less than or similar to 10(-8) of its bolometric luminosity. The hard X-ray spectrum suggests a plasma temperature of about 100 MK. Commonly, X-ray emission from stellar winds is attributed to embedded shocks due to the intrinsic instability of the radiation driving. From qualitative considerations we conclude that this mechanism cannot account for the hardness of the observed radiation. There are no hints for a binary companion. Therefore the only remaining, albeit speculative explanation must refer to magnetic activity. Possibly related, WR 142 seems to rotate extremely fast, as indicated by the unusually round profiles of its optical emission lines. Our detection implies that the wind of WR 142 must be relatively transparent to X-rays, which can be due to strong wind ionization, wind clumping, or nonspherical geometry from rapid rotation.