8,559 research outputs found
Simulated X-ray Cluster Temperature Maps
Temperature maps are presented of the 9 largest clusters in the mock
catalogues of Muanwong et al. for both the Preheating and Radiative models. The
maps show that clusters are not smooth, featureless systems, but contain a
variety of substructure which should be observable. The surface brightness
contours are generally elliptical and features that are seen include cold
clumps, hot spiral features, and cold fronts. Profiles of emission-weighted
temperature, surface brightness and emission-weighted pressure across the
surface brightness discontinuities seen in one of the bimodal clusters are
consistent with the cold front in Abell 2142 observed by Markevitch et al.Comment: Submitted to Monthly Notices Royal Astronomical Societ
Modelling the properties of galaxies and clusters
This thesis examines various properties of galaxies and clusters within hierarchical models of structure formation. A simple model based on analytical scaling relations is applied to X-ray observations of clusters at low and high redshift, in an attempt to constrain cosmological parameters from their evolutionary properties. It is found that the density parameter, Ωo cannot be constrained using the data alone. Two independent constraints on the slope of the linear power spectrum, infer values of Ωo < 0.7 at 95 per cent confidence. The remainder of this thesis concentrates on the method of cosmological simulation, a self- consistent approach to the modelling of structure in the Universe. A parameter-space study is performed for the simplest model of galaxy formation: the radiative cooling of baryons within the cores of dark matter haloes. It is found that the properties of the galaxies in the simulations are insensitive to the range of parameters studied, with the exception of those that affect the cooling rate of the gas. For modest resolution and reasonable choices of physical parameters, the amount of baryons in galaxy material is around a factor of 2 too high. An investigation is then performed for including the effects of star formation and energy from supemovae (feedback) within cosmological simulations, to reduce the amount of gas that cools. The star formation rate is driven by the minimum density for which the stars formation occurs and, for high star formation efficiencies, is limited by the cooling rate of the gas. A successful model for feedback is found to require the prevention of reheated gas from cooling for a short period of time, as an attempt to mimick the properties of a multiphase medium. Finally, preliminary results are presented for simulations of a galaxy cluster, including the effects of radiative cooling, star formation and feedback. The properties of the cluster are found to vary significantly between models with and without feedback, due to the feedback reducing the star formation rate by reheating gas that cools
Oral History Interview: James Kay Thomas
This interview contains detailed information concerning the workings of the West Virginia legislature and the governor\u27s office from approximately 1932 to 1942. James Kay Morgan, a prominent Charleston lawyer and former West Virginia legislator, discusses his years in the House of Delegates, his career in the Air Force, and his subsequent civic and professional work in the Charleston area. The interview also covers the implementation of several important legislative enactments in West Virginia history, such as the 1932 Tax Limitation Amendment and the Consumer\u27s Sales Tax.https://mds.marshall.edu/oral_history/1235/thumbnail.jp
Queering the Narrative: Life Writing in the Bruce McKinney Collection
This dissertation problematizes the definition of autobiography by considering the Bruce McKinney Collection, an archive at the Kenneth Spencer Research Library at the University of Kansas, a communal autobiography of the lesbian and gay community of Kansas. While generally used as a research tool, I argue that the archive can also be a form of life writing, consisting of a narrative that moves between documents and items found within the collection. Collected by numerous people over the course of forty years, I present the Bruce McKinney Collection as a communal autobiography of lesbian and gay life in Kansas. The archive demonstrates the lesbian and gay community's desire to acquire queer space and establish queer visibility in towns across Kansas. Through acts of resistance, whether taking legal action against a major university, proposing social changes through a city council, or by having sex in public spaces, the lesbian and gay community has reconfigured social space to accommodate their own community. In turn, the queer archive reflects the history of this change. Itself a queer space, the archive grants legitimacy to the lesbian and gay community simply by existing. It acts as a form of resistance as people have gathered and preserved the different documents that reflect lesbian and gay history. Through the resistant act of collecting lesbian and gay history, the lesbian and gay community of Kansas has created its own communal autobiography, specifically The Bruce McKinney Collection
Pressure transmission and green strength of clays as affected by time of ageing
Perfect dry pressing could only be attained if the mix possessed the properties of water in so far as pressure transmission is concerned. There are many factors, however, which tend to interfere with the transmixxion sic of pressure in the clay block, such as, - Differences in grain size, friction between the grains, entrapped air, dragging of the clay on the sides of the mould box and many other minor causes. In an effort to solve some the problems that are of vital interest to the Dry Press industry, the Committee on Dry Press Process of the National Brick Manufacturers Association has carried on extensive research at the Missouri School of Mines and Metallurgy, Rolla, Mo. --Introduction, Page 1
- …