<p> The alpha decay properties of nuclei decaying across the N = 126 closed neutron configuration are examined. A systematic occurrence of isomerism is esteblished in the odd-odd N = 2.27 isotones from a detailed study of 214Fr and 216Ac. Energy level spacings of the odd-odd N = 125 isotones 208Bi, 210At, and 212Fr are found to exhibit a distinct· correspondence. The Mang shell model theory of alpha decay is evoked to explain the reduced width fluctuations of the even-odd N = 127 isotones. Theoretical and experimental results are also presented for the alpha decay of 215Ra. The new isotopes 222Th , 221Th , 218Ra, and . 217R a are synthesized and studied. Precise atomic masses are calculated for several nuclei from the measurement of alpha decay Q-values. </p> / Thesis / Doctor of Philosophy (PhD)

By shifting from a static, preservation-based approach to one that emphasizes the dynamic process of decay, architecture can be given a second life through a more human-centered perspective. This approach acknowledges the symbiotic relationship between human decay and architectural decay, and can lead to new possibilities for adaptive reuse and revitalization. Architecture and human remains have the potential for new life through the cycle of death and rebirth, so by repurposing abandoned architecture and utilizing human ashes as a sustainable resource, a cemetery can become a vibrant space that celebrates life and the natural world. This approach embraces the cyclical nature of life and the interconnectedness of all things. The cycle of life and death is an inherent part of the human experience, and the built environment is no exception. As buildings and infrastructure age and become obsolete, they are often left to decay and deteriorate. However, this process of decay can be transformed into an opportunity for new life and purpose. A proposed cemetery on the existing ruin that incorporates these principles can become a vibrant space that reflects the cyclical nature of life and provides a sustainable solution for honoring the dead. / Master of Architecture / By moving away from a static focus on preservation and embracing the natural process of decay, architecture can be rejuvenated from a human-centered perspective. This shift recognizes the close connection between human decay and the deterioration of buildings, opening up possibilities for adaptive reuse and revitalization. Both architecture and human remains hold the potential for new life through the cycle of death and rebirth. By repurposing abandoned structures and utilizing sustainable practices, such as recycling materials and embracing eco-friendly approaches, spaces can be transformed into vibrant environments that celebrate life and the natural world. This approach acknowledges the cyclical nature of life and highlights the interconnectedness of all things. The cycle of life and death is a fundamental part of the human experience, and the built environment is no exception. As buildings and infrastructure age and become obsolete, they often fall into disrepair. However, this process of decay presents an opportunity for renewal and finding new purpose. By incorporating these principles, proposals for revitalizing existing spaces can reflect the natural cycle of life while offering sustainable solutions to honor the past and shape the future. This abstract provides a broader perspective on the potential of architecture, emphasizing the transformative power of embracing decay and revitalizing spaces to create a more sustainable and interconnected built environment.

The success of many experiments at rare-isotope facilities, such as the National Superconducting Cyclotron Laboratory (NSCL), depends on achieving a level of statistics that is partly driven by the overall number of nuclei produced in the beam. One such future study at the NSCL requires maximizing the beam content of 34mCl. To prepare for this 34mCl study, an initial measurement to determine the 34mCl yields and overall beam purity was performed at the NSCL by utilizing a Beta-decay experimental station. Isotopes delivered to the experimental station were identified using standard time of flight and energy loss techniques. To explore ways of maximizing 34mCl production, 6 different beam energy settings that selected different rigidities for isotopic selection and altered its entrance angles before the beam went into the fragment separator, were utilized. The absolute intensity of the peak energies associated with the decay of 34mCl (1177, 2127, and 3304 keV) were determined, as well as the overall number of 34Cl atoms delivered, thereby enabling 34mCl yield and beam purity determinations for each beam setting.

<p> The prevailing theory of Migdal for predicting the excitation probabilities of an atom from α-decay of the nucleus, considers the α-particle, after it has been emitted by the nucleus, as following a classical trajectory and interacting with the atom quantum mechanically. Recently an attempt was made to properly model this quantum mechanical phenomenon, in one dimension, with a quantum wavefunction treatment of the decaying α-particle, but a discrepancy was found between the new predictions and that of the traditional method. In light of this discrepancy, we have studied the various approximations made in that work. Our results concur with recent follow up work suggesting that agreement should be found between a fully quantum mechanical model and with the classical model of α-particle propagation where the α-particle is treated as a point particle.</p> / Thesis / Master of Science (MSc)

Thirty-one excited levels in 153Eu and thirty-four in 155Eu have been located by means of the (3He,d) and beta decay reactions. The energies, intensities, and decay scheme classifications of forty-four gamma rays in 153Eu and fifty-two in 155Eu have been measured by means of singles and coincidence experiments using NaI and Ge(Li) detectors. Angular distribution studies of the reaction deuterons have been made a number of levels have neen assigned unique l values. An interpretation of the level schemes in terms of the Nilsson model have been attempted. / Thesis / Doctor of Philosophy (PhD)

The decays, <img width=119 height=32 align=center src=https://vtechworks.lib.vt.edu/bitstream/handle/10919/28846/image006.gif> and <img width=119 height=29 align=center src=https://vtechworks.lib.vt.edu/bitstream/handle/10919/28846/image008.gif> are studied using data collected at the CLEO II detector at the Cornell Electron Storage Ring. Both decays are identified using a partial reconstruction method where the <I>D<SUP>*</SUP></I> is detected only through a pion daughter from the decay <img width=64 height=25 align=center src=https://vtechworks.lib.vt.edu/bitstream/handle/10919/28846/image010.gif>. Because of the similarities in the analyses of the two modes, the ratio of the rates is measured in a way that is independent of the decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This ratio is equivalent to the ratio of the product of production fraction and lifetime for charged and neutral B mesons, <img width=31 height=29 align=center src=https://vtechworks.lib.vt.edu/bitstream/handle/10919/28846/image012.gif>. It is combined with measurements of the lifetime ratio to obtain the ratio of charged and neutral B meson production at the Y(4S) resonance, <img width=175 height=29 align=center src=https://vtechworks.lib.vt.edu/bitstream/handle/10919/28846/image014.gif>. / Ph. D.

There are contradictory thoughts associated with ruins. Mainly when we hear the word ruin, it reminds us of glorious ancient structures that evoked an aesthetic pleasure and inspired artists and philosophers throughout the history. But it also has a negative feeling, it means to destroy to turn into decay. The former is the way that we feel about ancient ruins but our way of thinking about the ruins of modern times is different. There are different reasons for this duality and this thesis firstly attempts to explore the reasons behind this ambivalent attitude. Secondly to answer why ruins of our own time are considered invaluable, why they deserve our attention, how their qualities can offer different ways of remembrance and challenge the common perception of history and how their existence can arouse the topic of otherness in the urban context and provide a physical space for alternative cultural activities. The design project focuses on an early twentieth century ruin in Baltimore, Maryland. The former theater building had a relatively short period of splendor followed by several alterations and decades of abandonment and decay. Through an architectural intervention, the project aims to understand and appreciate the history and qualities of the ruined theater and integrate these qualities into the atmosphere of the new space, binding the old and the new together and at the same time, retaining the incomplete character of the ruin. / Master of Architecture / Mainly when we hear the word ruin, we think of famous ancient ruin sites like the Colosseum, Acropolis or Angkor Wat. It reminds us of glorious ancient structures that evoked an aesthetic pleasure and inspired artists. But the word ruin is also associated with negative feelings. It means to disintegrate, to reduce to a state of decay, to collapse. The way we feel about the ruins of our own time is mostly associated with the latter. Modern ruins are mostly seen as unpleasant. Places that provide a space for undesirable activities and are linked to crime and, thus, threatening the safety of the residents in that area. As a result of this attitude, they become an ignored and marginalized part of the cities. Although ruins have some of the mentioned negative possibilities, they also contain positive qualities and potentials that I explore in this thesis. There are different reasons for these ambivalent feelings about ancient and modern ruins and this thesis studies the reasons behind it. This thesis provides answers to questions of why ruins of our own time are considered invaluable, why they deserve our attention and how their existence can arouse the topic of otherness in the urban context and provide a physical space for alternative cultural activities. The design project focuses on an early twentieth century ruin in Baltimore, Maryland. The former theater building had a relatively short period of splendor followed by several alterations and decades of abandonment and decay. Through an architectural intervention, the project aims to understand and appreciate the history and qualities of the ruined theater and integrate these qualities into the atmosphere of the new space, binding the old and the new together and at the same time, retaining the incomplete character of the ruin.

Radioactive decay of nuclei via emission of ??-particles is studied using three different theoretical approaches, viz: the quasi-bound state wavefunction approach (QSWA), the superasymmetric ??ssion model (SAFM) and the semiclassical approximation (QCA). The half-lives of the radioactive nuclei, calculated using these methods, are compared with each other and with available experimental data. The resonance wavefunction is obtained by numerically integrating the Schrödinger equation with outgoing boundary conditions. The sensitivity of the calculated decay widths to two particular parameter sets of the Woods-Saxon (WS) optical potentials are studied. Double folding (DF) model calculations to obtain the bare ??-nucleus potential have been carried out with the Reid M3Y effective nucleon-nucleon (NN) interactions. The exchange part of the interaction was taken to be of zero-range pseudo-potential and the density dependence of the NN interaction is accounted for. The effectiveness of the method is demonstrated using both even-even and odd-mass spherical nuclei. / Physics / MSC (PHYSICS)

Estuda-se o transporte de portadores de carga no interior de um isolante dotado de centros profundos de retenção de carga. Supõe-se que os portadores tenham sido depositados na superfície livre do isolante por meio de uma descarga corona rápida e que ai a densidade superficial de carga decaia exponencialmente. Para obter-se o campo elétrico E = E (x,t) no interior do isolante. Integra-se essa equação pelo método das características e obtêm-se expressões analíticas para as linhas de corrente x = x (t,te) (te, designando o tempo de saída da carga da superfície) e para o campo elétrico E = E (t,te) ao longo de cada uma das linhas. São apresentadas famílias de curvas x = x(t,te) e de E = E(t,te),. Eliminando-se graficamente te entre as duas famílias, obtem-se a família de curvas E = E(x) parametrizada em t. Usou-se planímetro para determinar a área debaixo de cada curva E = E(x), e com isso constrói-se a curva de decaimento de potencial / The transport of charge carriers in presence of bulk traps inside an insulator. It is supposed that the carriers were deposited on the surface by a pulse of charge decaying thereafter exponentially with the time. In order to find the electric fielhd electric field E(x,t), the method of characteristics is employed, taking as parameter the time te when the leaves the surface; and ththeir position X=(t,te) and the electric field E=E(x,te) are obtained. By graphicall eliminatination, curves of E(x) are obtained for various times t. A planimeter was used to find the potential at every time as a function of the time

Graduation date: 2005