Source: Dissertation Abstracts International, Volume: 39-03, Section: B, page: 1352. / Thesis (Ph.D.)--The Florida State University, 1978.

by Hui Yuk Tak. / Parallel title in Chinese characters. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 46-47.

A safe treatment and disposal of spent Tri-Structural Isotropic (TRISO) coated fuel particles is one of the most important issues for developing the next generation of nuclear reactors, such as a Very High Temperature Reactor (VHTR). The project investigates the encapsulation of surrogated TRISO particles in Glass-Graphite Composite (GGC) and in Alumina Borosilicate Glass (ALBG) and compares their geological performance in the repository. The study deals with the assessment and performance of both matrices in a geological repository's conditions, measuring their chemical durability for 28 days at temperatures ranging 25-90°C and using American Standard for Testing Material (ASTM-C1220-98). The leach test revealed that only sintered ALBG with TRISO particles doped in cesium oxide could provide a safe Engineering Barrier System (EBS). The thermal property of the matrices was examined by measuring their thermal diffusivities. The thermal diffusivity of ALBG bearing various proportions of TRISO particles was measured experimentally using Laser Flash Analysis (LFA). The experimental results validated through a numerical method using Image Based Modelling (IBM). The effect of the porosity in decreasing the thermal diffusivity of TRISO particles was also discussed. In addition, the study deals with the immobilisation of ion exchange resins (doped with radioactive and non-radioactive cesium and cobalt) in borosilicate glass. The thermal analysis revealed that a successful immobilisation could be achieved once the sulfur functional group in the resin was decomposed and evaporated in a form of SO2/SO. The minimum required temperature of the heat treatment was 500°C under air environment as a pre-conditioning stage before immobilisation.

This thesis describes work towards the search for a low energy excess of electromagnetic events in the MicroBooNE detector. A background primer on the current state of neutrino physics is provided, including a description of the MiniBooNE detector and its published observation of an excess of electromagnetic events at low energies. A description of the MicroBooNE Liquid Argon Time Projection Chamber (LArTPC) detector is given, along with a description of the event selection and reconstruction algorithms developed to select electron neutrino charge-current interactions. A MiniBooNE-like signal is simulated in MicroBooNE with assumptions about the origin of the excess, and the sensitivity to observe such a signal above backgrounds in MicroBooNE is computed. An additional analysis is presented which constrains a dominant background in the MicroBooNE low energy excess search: the beam-intrinsic electron neutrino interactions which come from kaon decay in the beam-line. An essential step in this analysis is to reconstruct the energy of muon neutrino charge-current interactions in which the muon produced in the interaction escapes the detector. A publication detailing the algorithm which leverages the phenomenon of multiple Coulomb scattering to reconstruct the energy of escaping muons is provided as an appendix.

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Source: Dissertation Abstracts International, Volume: 34-04, Section: B, page: 1680. / Thesis (Ph.D.)--The Florida State University, 1973.

Source: Dissertation Abstracts International, Volume: 34-03, Section: B, page: 1215. / Thesis (Ph.D.)--The Florida State University, 1973.

Monte Carlo simulations are performed to study phase transitions of several systems. The 3D Ising model, the 2D 10-state Potts model, the 3D 3-state Potts model, and the SU(2) and SU(3) lattice gauge theories are considered. / For $L\sp{D}$ block geometries, we calculate the density of states and obtain high precision estimates for the leading partition function zeros. The finite-size scaling analysis of the first zero allows the extraction of the critical exponent $\nu$. For first-order phase transitions, the analysis of the specific heat gives an estimation of the latent heat. For $L\sp{D-1}$ $\infty$ cylindrical geometries, we determine the mass-gap m = 1/$\xi$ ($\xi$ is the correlation length). The finite-size scaling analysis of the mass-gap yields another estimate of the critical exponent $\nu$. The often exploited universality between the SU(2) gauge theory and the 3D Ising model critical exponents is confirmed. Our results show also a consistency between the SU(3) and the 3D 3-state Potts model critical exponent $\nu$. / Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5329. / Major Professor: Bernd A. Berg. / Thesis (Ph.D.)--The Florida State University, 1991.

In this dissertation several two dimensional statistical systems exhibiting discrete Z(n) symmetries are studied. For this purpose a newly developed algorithm to compute the partition function of these models exactly is utilized. The zeros of the partition function are examined in order to obtain information about the observable quantities at the critical point. This occurs in the form of critical exponents of the order parameters which characterize phenomena at the critical point. The correlation length exponent is found to agree very well with those computed from strong coupling expansions for the mass gap and with Monte Carlo results. / In Feynman's path integral formalism the partition function of a statistical system can be related to the vacuum expectation value of the time ordered product of the observable quantities of the corresponding field theoretic model. Hence a generalization of ordinary scale invariance in the form of conformal invariance is focussed upon. This principle is very suitably applicable, in the case of two dimensional statistical models undergoing second order phase transitions at criticality. The conformal anomaly specifies the universality class to which these models belong. From an evaluation of the partition function, the free energy at criticality is computed, to determine the conformal anomaly of these models. The conformal anomaly for all the models considered here are in good agreement with the predicted values. / Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5329. / Major Professor: Dennis W. Duke. / Thesis (Ph.D.)--The Florida State University, 1991.