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UNT Theses and Dissertations
Energy Losses of Protons Projected through a Plasma Due to Collisions with Electrons of the Plasma for a Variety of Non-Maxwellian Electron Velocity Distributions
Date: August 1961
Creator: Kregel, Mark Douglas
Description: The purpose of this thesis is to study energy losses suffered by protons in traversing a plasma through collision with the electrons of the plasma. For these electrons a variety of non-Maxwellian velocity distributions are assumed.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc130468/
An entropic approach to the analysis of time series.
Date: December 2001
Creator: Scafetta, Nicola
Description: Statistical analysis of time series. With compelling arguments we show that the Diffusion Entropy Analysis (DEA) is the only method of the literature of the Science of Complexity that correctly determines the scaling hidden within a time series reflecting a Complex Process. The time series is thought of as a source of fluctuations, and the DEA is based on the Shannon entropy of the diffusion process generated by these fluctuations. All traditional methods of scaling analysis, instead, are based on the variance of this diffusion process. The variance methods detect the real scaling only if the Gaussian assumption holds true. We call H the scaling exponent detected by the variance methods and d the real scaling exponent. If the time series is characterized by Fractional Brownian Motion, we have H¹d and the scaling can be safely determined, in this case, by using the variance methods. If, on the contrary, the time series is characterized, for example, by Lévy statistics, H ¹ d and the variance methods cannot be used to detect the true scaling. Lévy walk yields the relation d=1/(3-2H). In the case of Lévy flights, the variance diverges and the exponent H cannot be determined, whereas the scaling d ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc3033/
Experimental Determination of the Scattering Cross-section of Ogives and Prolate Spheroids at Microwave Frequencies
Date: 1956
Creator: Rhoads, Wayne C.
Description: Because of the great difficulty of obtaining exact numerical values of cross-section, and because of the inherent uncertainties in interpreting and evaluating the approximate methods, accurate experimental cross-section data would be extremely useful to the radar engineer. It was with this purpose in mind that the present long-range research program in microwave scattering was undertaken. Of immediate interest were the scattering properties of the prolate spheroid, the ogive (formed by rotating the minor segment of a circle around the chord), and, for comparison, the long cylinder.
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Permallink:digital.library.unt.edu/ark:/67531/metadc107875/
Exploration of hierarchical leadership and connectivity in neural networks in vitro.
Date: December 2008
Creator: Ham, Michael I.
Description: Living neural networks are capable of processing information much faster than a modern computer, despite running at significantly lower clock speeds. Therefore, understanding the mechanisms neural networks utilize is an issue of substantial importance. Neuronal interaction dynamics were studied using histiotypic networks growing on microelectrode arrays in vitro. Hierarchical relationships were explored using bursting (when many neurons fire in a short time frame) dynamics, pairwise neuronal activation, and information theoretic measures. Together, these methods reveal that global network activity results from ignition by a small group of burst leader neurons, which form a primary circuit that is responsible for initiating most network-wide burst events. Phase delays between leaders and followers reveal information about the nature of the connection between the two. Physical distance from a burst leader appears to be an important factor in follower response dynamics. Information theory reveals that mutual information between neuronal pairs is also a function of physical distance. Activation relationships in developing networks were studied and plating density was found to play an important role in network connectivity development. These measures provide unique views of network connectivity and hierarchical relationship in vitro which should be included in biologically meaningful models of neural networks.
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Permallink:digital.library.unt.edu/ark:/67531/metadc9775/
Extinguishment of a Low-pressure Argon Discharge by a Magnetic Field
Date: January 1964
Creator: Criswell, David Russell
Description: The experiment in this study involves the extinguishment of a low-pressure argon discharge by a magnetic field.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc108257/
Foil Depression Factors for Disc-shaped Detectors
Date: June 1954
Creator: Gallagher, Tom Lewis
Description: The generalized data which are presented in this thesis are the culmination of the determination of the foil depression factor using oblate spheroidal coordinates.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc130367/
Fractional Brownian motion and dynamic approach to complexity.
Date: August 2007
Creator: Cakir, Rasit
Description: The dynamic approach to fractional Brownian motion (FBM) establishes a link between non-Poisson renewal process with abrupt jumps resetting to zero the system's memory and correlated dynamic processes, whose individual trajectories keep a non-vanishing memory of their past time evolution. It is well known that the recrossing times of the origin by an ordinary 1D diffusion trajectory generates a distribution of time distances between two consecutive origin recrossing times with an inverse power law with index m=1.5. However, with theoretical and numerical arguments, it is proved that this is the special case of a more general condition, insofar as the recrossing times produced by the dynamic FBM generates process with m=2-H. Later, the model of ballistic deposition is studied, which is as a simple way to establish cooperation among the columns of a growing surface, to show that cooperation generates memory properties and, at same time, non-Poisson renewal events. Finally, the connection between trajectory and density memory is discussed, showing that the trajectory memory does not necessarily yields density memory, and density memory might be compatible with the existence of abrupt jumps resetting to zero the system's memory.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc3992/
Gamma Ray Response of a CsI(T1) Crystal to 14 Mev Neutrons
Date: August 1958
Creator: Young, Jack Carter
Description: The purpose of this paper is to study the possible excited states in the nucleus of Cs133. At North Texas State College a 100-Kev Cockcroft-Walton accelerator has been constructed for use as a neutron source for exciting various nuclei and for studying the gamma spectra obtained to determine their energy levels.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc108020/
Gamma Rays from Cs¹³³ by Inelastic Scattering of Neutrons
Date: August 1960
Creator: McDonald, Perry Frank
Description: The purpose of this investigation was to observe the excited states of the Cs¹³³ nucleus when neutrons are inelastically scattered from the nucleus.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc108105/
Gamma Rays from Neutron Excitation of Cs133
Date: January 1959
Creator: Lamb, Billy Leonard
Description: This thesis explores gamma rays from neutron excitation of Cs133.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc108026/