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.

[EN] Power and flow oscillations in a BWR are very undesirable. One of the major concerns is to ensure, during power oscillations, compliance with GDC 10 and 12. GDC 10 requires that the reactor core be designed with appropriate margin to assure that specified acceptable fuel design limits will not be exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. GDC 12 requires assurance that power oscillations which can result in conditions exceeding specified acceptable fuel design limits are either not possible or can be reliably and readily detected and suppressed. If the oscillation amplitude is large, before the scram occurs the fuel rods may experience periodic dry-out and rewetting, or if the oscillation is larger enough, extended dry-out. The Decay Ratio (DR) is the typical linear stability figure of merit. For analytical estimation of DR frequency domain codes are very useful. These types of codes are very fast and their results are very robust in comparison with time domain codes, whose results may be dependent on numeric scheme and nodalization. The only drawback of frequency domain is that you are limited to the linear domain; however, because of regulatory requirements imposed by GDC-12, reactors must remain stable and, thus, reactors always operate in the linear domain. LAPUR is a frequency domain stability code that contains a mathematical description of the core of a boiling water reactor. It solves the steady state governing equations for the coolant and fuel, and the dynamic equations for the coolant, fuel and the neutron field in the frequency domain. Several improvements have been performed to the current version of the code, LAPUR5, in order to upgrade it for use with new fuel design types. The channel geometry has been changed from constant area to variable area. The local losses due to the spacers and contractions along the flow path have been upgraded to use industry standard correlations. This new version is LAPUR 6. In this work, in order to check the correct implementation of these changes, a two-fold LAPUR 6 validation has been performed: First, an exhaustive validation of the models implemented has been performed, comparing single channels LAPUR 6 outputs against SIMULATE-3 results. Cofrentes NPP SIMULATE-3 thermal-hydraulic models have been independently validated against experimental data. Second, a Methodology for calculating Decay Ratios with LAPUR 6 has been developed, defining a validation matrix against analytical and plant measured decay ratios. Analysis of measured data from the Cofrentes NPP has shown that decay ratios have values lower than 0.3 confirming the large stability margin of Cofrentes NPP when proper operating procedures are followed, and the comparison with LAPUR shows deviations less than +/- 0.1. Past experience suggests that the uncertainty in low decay ratio ranges is usually larger than with higher decay ratio values. Finally a BWR noise generator has been used for estimating the uncertainty of the signal analyses methods used in this work for experimental estimation of decay ratio from the autocorrelation function of the APRM or LPRM power signals. / [ES] Las oscilaciones de potencia y caudal en un BWR no son deseables. Una de las principales preocupaciones es asegurar, durante oscilaciones de potencia, el cumplimiento de la GDC 10 y 12. GDC 10 requiere que el núcleo del reactor se haya diseñado con un margen adecuado para asegurar que los límites admisibles establecidos en el diseño del combustible no se excederán en cualquier condición de operación normal, incluyendo los efectos de los sucesos operacionales anticipados. GDC 12 requiere garantías de que las oscilaciones de potencia que pueden resultar en condiciones que excedan los límites admisibles establecidos de diseño del combustible, o bien no son posibles o puedan ser detectadas y suprimidas de forma pronta y segura. Si la amplitud de la oscilación es grande, antes de que se produzca el scram las varillas de combustible pueden experimentar secados y remojados periódicos, o si las oscilaciones son suficientemente grandes, un secado extendido. La tasa de amortiguamiento (DR) es la típica figura de mérito de la estabilidad lineal. Para la estimación analítica de la DR los códigos en el dominio de la frecuencia son muy usados. Este tipo de códigos son muy rápidos y sus resultados son muy robustos en comparación con los códigos en el domino temporal, cuyos resultados pueden depender del esquema numérico y la nodalización. El único inconveniente de los códigos en el dominio de la frecuencia es que está limitado al dominio lineal; sin embargo, como los requerimientos regulatorios impuestos por el GDC-12, los reactores deben permanecer estables y, por lo tanto, los reactores deben operar siempre en el dominio lineal. LAPUR es un código de estabilidad en el dominio de la frecuencia que contiene una descripción matemática del núcleo de un reactor de agua en ebullición. Resuelve las ecuaciones de conservación en estado estacionario para el refrigerante y el combustible, las ecuaciones dinámicas para el refrigerante, el combustible y el campo neutrónico en el dominio de la frecuencia. Se han realizado varias mejoras a la versión actual del código, LAPUR 5, con el fin de actualizarlo para su uso con los nuevos tipos de diseño de combustible. La geometría del canal se ha cambiado, el área ha pasado de ser constante a poder considerar área variable. El cálculo de las pérdidas locales debido a los espaciadores y contracciones a lo largo del camino que sigue el flujo se han actualizado, pasando a utilizar correlaciones estándar de la industria. Esta nueva versión del código se ha denominado LAPUR 6. En este trabajo, con el fin de verificar la correcta implementación de estos cambios, se ha realizado una doble validación del código LAPUR 6: En primer lugar se ha realizado una validación exhaustiva de los modelos implementados, comparando los valores de salida de LAPUR 6 para un canal con los resultados de SIMULATE-3. Los modelos termohidráulicos de la CN Cofrentes de SIMULATE-3 han sido validados de forma independiente con los datos experimentales. En segundo lugar se ha desarrollado una metodología para el cálculo de la tasa de amortiguamiento con LAPUR 6, definiendo una matriz de validación de los valores de tasa de amortiguamiento analíticos con valores medidos en la planta. Las tasas de amortiguamiento medidos en la Central Nuclear de Cofrentes tienen valores inferiores al 0.3, confirmando el gran margen de estabilidad de la Central Nuclear de Cofrentes cuando se siguen los procedimiento de operación adecuados, y la comparación con los resultados de LAPUR muestra desviaciones de menos de +/- 0.1. La experiencia acumulada sugiere que la incertidumbre para los rangos bajos de tasas de amortiguamiento es generalmente más grande que para los valores altos. Por último se ha utilizado un generador de señales BWR para la estimación de la incertidumbre de los métodos de análisis de señales utilizados en este trabajo para la estimación experimental de la DR, a partir de la funci / [CA] Les oscil·lacions de potència i flux en un BWR són molt poc desitjades. Una de les majors preocupacions és assegurar-se, durant les oscil·lacions de potència, del compliment de GDC 10 i 12. GDC 10 requerix que el nucli del reactor estiga dissenyat amb un marge apropiat per a assegurar que els limits admissibles establerts en el disseny del combustible no siguen superats davall cap condició d'operació normal, incloent els incidents esperats d'operació. GDC 12 requerix assegurar que les oscil·lacions de potència que poden resultar en condicions on es superen els limits admissibles establerts en el disseny del combustible no siguen possibles o puguen ser detectades de manera segura e immediata i suprimides. Si l'amplitud de les oscil·lacions és gran, abans que el scram ocórrega les barres experimenten un assecat i remullat periòdic, o si l'oscil·lació és prou gran, un assecat estés. La taxa d'amortiment (DR) és la típica figura de mèrit de l'estabilitat lineal. Per a l'estimació analítica de la DR són molt usats els codis en el domini de la freqüència. Este tipus de codis són molt ràpids i els seus resultats són molt robustos en comparació amb els codis en el domini temporal, els resultats del qual són molt dependents de l'esquema numèric i la nodalizació. L'únic inconvenient del domini de la freqüència és que està limitat al domini lineal, no obstant això, com els requeriments reguladors imposats pel GDC-12, els reactors han de mantener-se estables i, per tant, els reactors han d'operar sempre en el domini lineal. LAPUR és un codi d'estabilitat en el domini de la freqüència que conté una descripció matemàtica del nucli d'un reactor d'aigua en ebullició. Resol les equacions de govern estacionàries del refrigerant i el combustible, les equacions dinàmiques del refrigerant, el combustible i el camp neutrònic en el domini de la freqüència. S'han realitzat diverses millores a la versió anterior del codi, LAPUR 5, amb l'objectiu d'actualitzar-ho per al seu ús amb nous tipus de disseny de combustibles. La geometria del canal s'ha canviat d'àrea constant a variable. Les pèrdues locals degudes als espaciadors i contraccions al llarg del camí del flux s'han actualitzat per a utilitzar correlacions estàndard de la indústria. Esta nova versió és LAPUR 6. En este treball, amb l'objectiu de comprovar la correcta implementació d'estos canvis, s'ha realitzat una doble validació del LAPUR 6: Primer, s'ha realitzat una validació exhaustiva dels models implementats, comparant els valors d'eixida per a un canal de LAPUR 6 amb els resultats de SIMULATE-3. Els models termohidraúlics per a SIMULATE-3 de la Central Nuclear de Cofrentes s'han validat independentment amb dades experimentals. Segon, s'ha desenrotllat una Metodologia per al càlcul de la Taxa d'Amortiment amb LAPUR 6, definint una matriu de validació amb valors de taxes d'amortiment analítics i mesurats en la planta. Anàlisis de les dades mesurades en la Central Nuclear de Cofrentes mostren valors de les taxes d'amortiment inferiors al 0.3, confirmant el gran marge d'estabilitat de la Central Nuclear de Cofrentes quan se seguix un adequat procediment d'operació, i la comparació amb LAPUR mostra desviacions inferiors al +/- 0.1. L'experiència acumulada mostra que la incertesa en el rang de taxes d'amortiment baixes és normalment major que per a valors alts de les taxes d'amortiment. Finalment s'ha utilitzat un generador de senyals per a estimar la incertesa dels mètodes d'anàlisi del senyal utilitzats en este treball per a l'estimació experimental de la taxa d'amortiment emprant la funció d'autocorrelació dels senyals de potència APRM o LPRM. / Melara San Román, J. (2016). PREDICTIVE METHODS FOR STABILITY MARGIN IN BWR [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61307

Airborne transmission of most respiratory viruses was not widely acknowledged until the COVID-19 pandemic. For viruses to transmit between infected and healthy individuals, they must remain stable (i.e., "survive") in aerosols and droplets. Their stability is influenced by many factors including temperature, relative humidity (RH), physico-chemical properties of the carrier droplet, and virus strain. However, the exact mechanisms of viral inactivation remain unknown. The primary aim of this work was to delineate the complex interactions occurring within aerosols and droplets and the mechanisms that drive inactivation of viruses within them. Initially, we reviewed and synthesized existing studies on aerosols and droplets to identify knowledge gaps regarding these mechanisms. This system is highly complex, with various factors influencing viral stability interacting with each other. We recommend that future studies focus on more physiologically relevant aerosol and droplet sizes and fluids to better understand this system in real-world contexts. As previous studies often used large droplets, we shifted our focus to the environmental stability of enveloped viruses (Phi6, influenza virus, and SARS-CoV-2) as a function of initial droplet size (50, 5, and 1 µL) and evaporation kinetics. Our findings indicated that RH had a greater impact on viral decay in large droplets compared to small droplets, and in addition, suggested caution when using surrogates to study the stability of pathogenic viruses. Subsequently, we explored how gas-phase composition and pH affect influenza stability by manipulating the surrounding air. Results indicated that pH has little influence on influenza virus in saliva droplets, implying that another factor may drive decay. Lastly, we examined the survival of influenza virus in the presence of reactive oxygen species (ROS) scavengers, finding that certain ROS may play a significant role in virus inactivation. / Doctor of Philosophy / Airborne transmission of most respiratory viruses was not widely acknowledged until the COVID-19 pandemic. For these viruses to spread from one person to another, they must survive in aerosols and droplets. Research has shown that their survival depends on many factors including temperature, humidity, physical and chemical properties of the droplets, and the type of virus. However, we still do not fully understand how viruses decay. The main goal of this work was to understand the complex interactions within aerosols and droplets that lead to virus decay. Initially, we reviewed existing research to find out what we already know and what gaps exist in our knowledge. This is a very complicated system because it involves many factors that can interact with each other. We recommend that future studies use droplet sizes that are more similar to those found in real-world situations and real respiratory fluids, such as saliva. Since many previous studies used droplets that are much larger than what we expel, we determined whether virus survival depends on droplet size and how droplets evaporate. We found that humidity had a greater impact on virus decay in large droplets compared to small droplets. Next, we explored how the air surrounding saliva droplets containing the flu virus affects the virus and the pH of droplets. We found that pH has little effect on flu virus decay, suggesting that another factor may drive decay. Instead, our results indicated that very reactive chemicals may be responsible for virus decay.

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