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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.
151

Characterization of Rodessa Formation Reservoir (Lower Cretaceous) in Van Field, Van Zandt County, Texas

Triyana, Yanyan 30 September 2004 (has links)
The Rodessa Formation is one of the major oil and gas reservoirs in the East Texas Basin. In Van Field, the upper Rodessa Formation consists of interbedded biotic and abiotic mudstones to grainstones. The lower Rodessa is composed of interbedded sandstones, shales, and limestones called the Carlisle Member. Based on core and well log interpretation, the Rodessa Formation was deposited on a broad, restricted, shallow marine platform interpreted to be lagoonal, subtidal, and intertidal. Both Rodessa limestone and sandstone have been altered significantly by diagenetic processes that include micritization, cementation, dissolution, neomorphism and compaction. Dissolution is the main factor that resulted in enhanced porosity and permeability while cementation adversely affected porosity. Diagenesis is interpreted to have begun in the marine phreatic environment and continued through the freshwater phreatic and shallow burial environments. Two reservoir units have been identified from core and well log interpretations. The potential reservoir within the Rodessa Formation occurs in the Carlisle Member which is composed mainly of medium to coarse grained sandstone with porosities and permeabilities in ranges of 8 to 11 percent and 46 to 896 millidarcies, respectively. The water saturation analysis has also shown the reservoir to be hydrocarbon bearing, having water saturation below 46 percent.
152

Modelling and control of satellite formations

Vaddi, Veera Venkata Sesha Sai 30 September 2004 (has links)
Formation flying is a new paradigm in space mission design, aimed at replacing large satellites with multiple small satellites. Some of the proposed benefits of formation flying satellites are: (i) Reduced mission costs and (ii) Multi mission capabilities, achieved through the reconfiguration of formations. This dissertation addresses the problems of initiatialization, maintenance and reconfiguration of satellite formations in Earth orbits. Achieving the objectives of maintenance and reconfiguration, with the least amount of fuel is the key to the success of the mission. Therefore, understanding and utilizing the dynamics of relative motion, is of significant importance. The simplest known model for the relative motion between two satellites is described using the Hill-Clohessy-Wiltshire(HCW) equations. The HCW equations offer periodic solutions that are of particular interest to formation flying. However, these solutions may not be realistic. In this dissertation, bounded relative orbit solutions are obtained, for models, more sophisticated than that given by the HCW equations. The effect of the nonlinear terms, eccentricity of the reference orbit, and the oblate Earth perturbation, are analyzed in this dissertation, as a perturbation to the HCW solutions. A methodology is presented to obtain initial conditions for formation establishment that leads to minimal maintenance effort. A controller is required to stabilize the desired relative orbit solutions in the presence of disturbances and against initial condition errors. The tradeoff between stability and fuel optimality has been analyzed for different controllers. An innovative controller which drives the dynamics of relative motion to control-free natural solutions by matching the periods of the two satellites has been developed under the assumption of spherical Earth. A disturbance accommodating controller which significantly brings down the fuel consumption has been designed and implemented on a full fledged oblate Earth simulation. A formation rotation concept is introduced and implemented to homogenize the fuel consumption among different satellites in a formation. To achieve the various mission objectives it is necessary for a formation to reconfigure itself periodically. An analytical impulsive control scheme has been developed for this purpose. This control scheme has the distinct advantage of not requiring extensive online optimization and the cost incurred compares well with the cost incurred by the optimal schemes.
153

Stereochemical aspects of the cycloheptane ring

Engle, John Edward 12 1900 (has links)
No description available.
154

A study of the rheology, stability and pore blocking ability of non-aqueous colloidal gas aphron drilling fluids

Shivhare, Shishir Unknown Date
No description available.
155

Dawson Trotman's Personal Spiritual Disciplines as the Foundation for His Great Commission Ministry

Reynolds, Jeffrey Paul 31 March 2015 (has links)
DAWSON TROTMAN'S PERSONAL SPIRITUAL DISCIPLINES AS THE FOUNDATION FOR HIS GREAT COMMISSION MINISTRY Jeffrey Paul Reynolds, Ph.D. The Southern Baptist Theological Seminary, 2014 Chair: Dr. Timothy K. Beougher This dissertation argues that Dawson Trotman's personal spiritual disciplines served as the foundation of his Great Commission ministry. Chapter 1 defines important terms and states the case for researching Dawson Trotman's views on the subject. Chapter 2 presents a biographical sketch of Dawson Trotman's life, giving particular attention to his understanding of Great Commission ministry with emphasis on his understanding of the gospel and of the process of discipleship. Chapter 3 explores Trotman's personal spiritual disciplines and the bases upon which he developed his understanding of such disciplines. Attention is given to the scriptural sources from which he derived his intensive regimen of regularly practiced personal spiritual disciplines and other sources that influenced his thinking in these disciplines. Furthermore, this chapter examines Trotman's core theological beliefs regarding his personal spiritual disciplines and the methods he employed in practicing them. Chapter 4 chronicles Trotman's Great Commission ministry both in terms of its history and the vision Trotman proposed not long before his untimely death. This chapter concludes with an analysis of Trotman's understanding spiritual reproduction as the cornerstone of his Great Commission ministry and legacy. Chapter 5 bridges the gap between Trotman's intense regimen of personal spiritual disciplines and his Great Commission ministry. Specifically, this chapter illustrates how Trotman's personal spiritual disciplines provided the foundation, motivation, and urgency for his disciple-making ministry, and it shows that Trotman felt that his personal spiritual disciplines also provided for the effectiveness of his Great Commission ministry. Chapter 6 summarizes the research, presents conclusions, and offers some insight as to how Trotman can and should inform contemporary Christians as they seek to obey Christ's Great Commission.
156

Triggered and spontaneous star formation in the W3 giant molecular cloud

Allsopp, James January 2012 (has links)
The thesis goes on to extend the work of Bretherton (2003) and Moore et al. (2007) on the W3 Giant Molecular Cloud, by performing NH3 follow up of a sample of the cores discovered in the 850um SCUBA map and observing the whole cloud in 13CO(J=1-0) and C18O(J=1-0). - The NH3(1,1) and NH3(2,2) observations of the SCUBA cores used the fact that NH3 only traces the densest regions of the cloud, and hence can be used to find the temperature and kinematics of the cores themselves. This was used to test if the individual cores were virially bound, and from this find if cores in the more densely star-forming region of the cloud (High-Density Layer, HDL) were more likely to be bound than those in the Low-Density Layer (LDL). There are a mixture of virially bound and unbound cores in both the HDL and the LDL but no statistical difference in ratio of these between the two regions. This has an important bearing on models of environmentally-dependent star-formation, which divide into two categories; those, such as Collect and Collapse (Dale et al., 2007), which state that external pressures create dense structure, and those such as Radiatively- Driven Instability (RD I) (Bertoldi, 1989), which state that those external pressures cause dense structure to collapse. The evidence from this thesis favours models in which dense structure is created according to the Collect and Collapse scenario.
157

Three essays on sequential bargaining theory

Flamini, Francesca January 2002 (has links)
No description available.
158

A passion to exist : cultural entrepreneurship and the search for authenticity in Cornwall

Burton, Robert Edward January 2002 (has links)
No description available.
159

The regulation of polarised growth in the pathogenic form of Candida albicans

Stewart, Elaine January 1988 (has links)
The dimorphic yeast <i>Candida albicans</i> is capable of growth in a budding yeast form and in a mycelial form. Growing in the yeast form in the digestive and vaginal tracts it normally presents no problems to the host; however, when the dimorphic transition takes place and mycelial growth is initiated, symptoms of candidiasis manifest in the host tissues. This thesis studies the control of the dimorphic response and investigates some of the cellular changes which accompany it. Germ tube formation was induced in a defined amino acids/salts medium. Temperature, pH and culture density were critical factors in stimulating the dimorphic response. Different percentages of term tube formation were recorded for eight different strains of <i>C. albicans</i>. Each strain also acidified the growth medium to a different extent; this was correlated to the extent of filamentation of each strain. Internal pH changes were monitored using the weak and technique and <sup>31</sup>P nuclear magnetic resonance spectroscopy during bud and germ tube formation. In mycelial cells there was an initial increase in internal pH from 6.8 to around 8.0, followed by a gradual decrease to neutrality at the actual time of germ tube emergence. Cells in the budding form of growth did not exhibit such a marked increase in cytoplasmic alkalinisation. Mutant strains which were unable to produce germ tubes did not show cytoplasmic alkalinisation under conditions which would normally promote mycelial growth. Activation of the plasmamembrane ATPase may account for this increase in internal pH since diethylstilboestrol inhibited cytoplasmic alkalinisation and germ tube formation without affecting cell viability. Weak bases induced artificially, a rise in internal pH which was accompanied by germ tube formation. Potassium ions were found to enter cells as protons were expelled at the initiation of mycelial growth. Lactic acid prevented any rise in internal pH during germ tube formation. It also collapsed the ΔpH of the cells preventing growth by bud or germ tube formation. This may relate to the observation that endogenous <i>Lactobacilli</i> compete with <i>C. albicans</i> in the vagina and may explain why topically applied live yoghurt cultures soothe vaginal candidiasis. Transport of methionine was found not to be significantly different in cells induced to the budding or mycelial form. Transport or arginine and glutamate was induced by growing cells in the presence of these amino acids. The amino acid pool levels changed during the dimorphic process in <i>C. albicans</i>. A rapid increase in the pool level was shown within the first hour of both bud and hyphal growth followed by a gradual decrease. Little or no evidence was found in support of the hypothesis that the formation of hyphae is a response to nutrient starvation.
160

The matrices and rims of unequilibrated chondrites : Origins, metamorphism and alteration

Alexander, C. M. O'D. January 1987 (has links)
No description available.

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