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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Validated Prediction Of Pressurant Gas Requirements In Cryogenic Run Tanks At Subcritical And Supercritical Pressures

De Quay, Laurence 11 December 2009 (has links)
The development, testing, and use of liquid propellant and hybrid rocket propulsion systems for spacecraft and their launch vehicles routinely involves the use of cryogenic propellants. These propellants provide high energy densities that enable high propulsive efficiency and high engine thrust to vehicle weight ratios. However, use of cryogenic propellants also introduces technical problems not associated with other types of propellants. One of the major technical problems is the phenomenon of propellant tank pressurant and ullage gas collapse. This collapse is mainly caused by heat transfer from most of the ullage gas to tank walls and interfacing propellant, which are both at temperatures well below those of this gas. Pressurant gas is supplied into cryogenic propellant tanks in order to initially pressurize these tanks and then to maintain required pressures as propellant is expelled from these tanks. The cryogenic propellants expelled from the tanks feed rocket engine assemblies, subassemblies, and components at required interface pressures and mass flow rates. The net effect of pressurant and ullage gas collapse is increased total mass and mass flow rate requirements of pressurant gases. For flight vehicles this leads to significant and undesirable weight penalties. For rocket engine component and subassembly ground test facilities this results in high construction and operational cost impacts. Accurate predictions of pressurant gas mass transfer and flow rate requirements are essential to the proper design of systems used to supply these gases to cryogenic propellant tanks. While much work has been done in the past for predicting these gas requirements at low subcritical tank pressures, very little has been done at supercritical tank pressure conditions and there are selected cases where errors of analytical predictions are high. The objectives of this study are to develop a new generalized and improved computer program to determine pressurant gas requirements at both subcritical and supercritical tank pressure conditions, and then evaluate and validate the consistent accuracy of this program over a wide range of conditions by comparison of program results to empirical data.
272

Subsurface Facies Analysis of the Rose Run Sandstone Formation in south eastern Ohio

Nwaodua, Emmanuel Chukwukamadu 29 July 2008 (has links)
No description available.
273

CO<sub>2</sub> Sequestration in Saline Aquifer: Geochemical Modeling, Reactive Transport Simulation and Single-phase Flow Experiment

Zerai, Biniam January 2006 (has links)
No description available.
274

Making Meaning Outside of the System: A Narrative Exploration of Recovery Within a Peer-run Setting

Goldsmith, Rachel E. 28 April 2010 (has links)
No description available.
275

THERE IS MORE TO LIFE THAN EXPECTED VALUES: RESULTS OF FREE DISTRIBUTIONS OF MULTIPLE-PLAY GAMBLES

Bristow, Robert Evan 04 May 2011 (has links)
No description available.
276

Evaluating Depositional Complexity and Compartmentalization of the Rose Run Sandstone (Upper Cambrian) in Eastern Ohio

Shah, Mihir P. 19 December 2013 (has links)
No description available.
277

Can Minimum Wage Help Forecast Unemployment?

Tyliszczak, John 22 September 2017 (has links)
No description available.
278

Availability and Toxicity of Nickel to Lotic Periphyton and Macroinvertebrates

Bessom, Stephanie Marie 30 December 2008 (has links)
No description available.
279

Seismic Reflection Profiling near Middletown, Ohio and Interpretation of Precambrian Deformational Settings

Peterman, David Joseph 01 June 2016 (has links)
No description available.
280

The identification and analysis of acid mine drainage sources to the surface waters of the Robinson Run Sub-watershed

Brothers, Christopher A. January 2001 (has links)
No description available.

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