Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 130-135).

Casimir and Casimir-Polder effects are forces between electrically neutral bodies and particles in vacuum, arising entirely from quantum fluctuations. The modification to the vacuum electromagnetic-field modes imposed by the presence of any particle or surface can result in these mechanical forces, which are often the dominant interaction at small separations. These effects play an increasingly critical role in the operation of micro- and nano-mechanical systems as well as miniaturized atomic traps for precision sensors and quantum-information devices. Despite their fundamental importance, calculations present theoretical and numeric challenges, and precise atom-surface potential measurements are lacking in many geometric and distance regimes. The spectroscopic measurement of Casimir-Polder-induced energy level shifts in optical-lattice trapped atoms offers a new experimental method to probe atom-surface interactions. Strontium, the current front-runner among optical frequency metrology systems, has demonstrated characteristics ideal for such precision measurements. An alkaline earth atom possessing ultra-narrow intercombination transitions, strontium can be loaded into an optical lattice at the “magic” wavelength where the probe transition is unperturbed by the trap light. Translation of the lattice will permit controlled transport of tightly-confined atomic samples to well-calibrated atom- surface separations, while optical transition shifts serve as a direct probe of the Casimir-Polder potential. We have constructed a strontium magneto-optical trap (MOT) for future Casimir-Polder experiments. This thesis will describe the strontium apparatus, initial trap performance, and some details of the proposed measurement procedure.

Made available in DSpace on 2018-08-01T22:57:29Z (GMT). No. of bitstreams: 1 tese_10671_Dissertação Final Clever Geraldo Coelho.pdf: 1370119 bytes, checksum: 200f0ce2aa7171e22a0b72495601ae00 (MD5) Previous issue date: 2017-02-20 / O cultivo do feijoeiro(Phaseolus vulgaris L.)além de sua importância econômica adquire no contexto nacional aspectos sociais e culturais. No Brasil, a produtividade média é considerada baixa, devido principalmente ao manejo inadequado da cultura. A interferência das plantas daninhas é considerada um fator limitante à produção do feijoeiro. Sendo assim, um dos objetivos desse trabalho é: estimar os parâmetros genéticos de 20 genótipos de feijão-comum em competição com trapoeraba afim de obtenção de informações importantes para a seleção e progresso do melhoramento da cultura. Assim, os 20 genótipos foram avaliados no ano agrícola 2015/2016 em casa telada no Departamento de Produção Vegetal no Centro de Ciências Agrárias e Engenharias da Universidade Federal do Espírito Santo (UFES). Foi utilizado o esquema fatorial simples 2 x 20; sendo o fator 1, presença e ausência de trapoeraba e fator 2, vinte genótipos de feijoeiro, num delineamento inteiramente casualizado, com três repetições. Avaliaram-se as seguintes características: diâmetro médio do caule (DMC); comprimento médio da planta (CMP); número de vagens por vaso (NVV); número de lóculos por vagem (NLV); número de grãos por vagem (NGV); porcentagem de lóculos vazios (%LV); total de grãos por vaso (TGV); peso total de grãos por vaso (PTG) e peso médio do grão (PMG).Foram estimados parâmetros genéticos: variância genotípica, variância ambiental, herdabilidade, coeficiente de variação genotípico, coeficiente de variação ambiental relação coeficiente de variação genotípico e ambiental e acurácia. Os altos valores de herdabilidade encontrados para a maioria dos caracteres, juntamente com coeficiente de variação genético e a razão coeficiente genético/coeficiente variação ambiental implica em métodos simples de seleção em função da pouca influência ambiental existente.Outro objetivo do trabalho foi avaliar a influência da planta daninha nas características morfológicas e nutricionais do feijoeiro, utilizando agora as cultivares comerciais: BRS Pontal, BRS Agreste, Ametista e BRS Estilo. O experimento foi instalado no ano agrícola de 2014/2015, em casa telada no Departamento de Produção Vegetal no Centro de Ciências Agrárias e Engenharias da Universidade Federal do Espírito Santo (UFES). Adotou-se o esquema fatorial 2 x 4, o fator 1 correspondeu a presença ou ausência de planta daninha e o fator 2 aos cultivares de feijão: BRS Pontal, BRS Agreste, BRS Ametista e BRS Estilo com delineamento inteiramente casualizado, dessa vez com cinco repetições. Foram os avaliados seguintes caracteres agronômicos:teor de clorofila (TC);número de vagens por planta (NVP); e produção de grãos por planta (PGP). Avaliou-se também o teor de N, P, K, Ca, Mg, Mn, Fe e Zn nos grãos do feijoeiro. A interação foi significativa para os teores de P, Mg, e Fe nos grãos, demonstrando que a competição com planta daninha pode prejudicar a alocação desses nutrientes, resultando em grãos de qualidade nutricional inferior.

The new ion guide isotope separator, IGISOL--4, at JYFL, Jyvaskyla has been commissioned, and new spectroscopy and structural measurements are reported here. The first optical measurements of radioactive (101,107)Mo isotopes, with definite spin assignments, are presented. The measurements provide insight into the development of the structure and deformation around N=60 for molybdenum. A clear, exaggerated odd--even staggering in the mean--square charge radii up to N=60, followed by an immediate change in character, shows the chain to possess a far less smooth shape development than previously thought. The measurements of 107Mo confirm this isotope to mark the peak of the deformation in molybdenum and these results, achieved in the limits of fission fragment production, display the improved capabilities of the IGISOL--4 facility (these two isotopes were too challenging to be studied previously at IGISOL--3).The commissioning stages of the electrostatic ConeTrap are detailed, from the initial off--line investigations (in comparison to detailed simulations), to the first successfully stored and extracted radioactive ions. The detection of a hyperfine resonance has been achieved from (stable) hafnium ions stored and extracted from the trap prior to resonant excitation, with no observable ion energy perturbations induced by the trapping. The observation of a resonant optical pumping effect on yttrium ion survival is presented. Pumping of an ionic ensemble within the Cooler--Buncher is shown to lead to a change in ion survival, directly observed through a change in the measured ion rates. The ConeTrap was observed to enhance this effect upon further storage of pre--pumped ions. A new, bespoke data acquisition system for collinear laser spectroscopy is presented. The microcontroller based system provides time stamping of photon arrival, a multiple photon tracker for two photon gating and full software control over photon time gates. A novel approach for searching for weak hyperfine peaks is implemented in the system. This `photon multiplication method' provides greater statistics on resonance peaks, providing a greatly increased accuracy in peak centroid determination.

This thesis describes the advances made towards a dual-species magneto-optical trap (MOT) of Li and Rb for use in photoassociation spectroscopy, Feshbach resonance studies, and, as long-term aspirations, the formation of ultracold heteronuclear polar molecules. The initial discussion will focus on a brief theoretical overview of laser cooling and trapping and the production of ultracold molecules from a cold atom source. Subsequently, details of the experimental system, including those pertaining to the required laser light, the vacuum chamber, and the computer control system will be presented. Finally, preliminary optimization and characterization measurements showing the performance of a single species Li MOT are introduced. These measurements demonstrated the loading of over 8 x 107 Li atoms directly into a MOT without the need for a Zeeman slower. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In the normal operation of quadrupole ion trap mass spectrometers, the trapped ions are ejected symmetrically through both the upper (detector) and lower(source) endcap electrodes during mass selective boundary ejection experiment. This reduces the sensitivity of the instrument by almost 50%. In this preliminary study, we altered the geometry parameters of the quadrupole ion traps to introduce asymmetry. The asymmetry displaced the ion cloud towards the detector endcap which resulted in a preferential ejection through this endcap, thus imparting directionality to the ejected ions and hence to the sensitivity enhancement. Two symmetrical mass analyzers have been taken up for numerical study. They include the Paul trap(QIT) and the cylindricaliontrap(CIT). Asymmetry to these geometries is introduced in two ways, one by varying the upper endcap hole radius alone and in other by stretching the trap along the upper endcap only. The escape velocity plots and mass selective boundary ejection simulations are used to demonstrate the directionality of ion ejection for these geometries. The simulations revealed a significant increase in the number of ions getting ejected in the direction of asymmetry.

Ion traps used in mass spectrometers are of two classes. One class consists of traps having three electrode geometries which have rotational symmetry about central axis. They are called axially symmetric ion traps. Paul trap, Cylindrical Ion Trap(CIT) are examples in this class. Other class of traps contain 2D electric field inside them which has same profile along the central axis due to translational symmetry. Linear Ion Trap(LIT) and Rectilinear Ion Trap(RIT) are examples in this class. In the ideal hyperbolic geometries of Paul trap and LIT, electric field is a perfectly linear function of distance from the center of the trap. But when these ideal geometries are simplified in to simpler geometries of the CIT and the RIT for ease in machining, linearity of field, which is a specialty of Paul trap and LIT is lost. In this thesis, an effort is made to optimize the field within the traps by using split electrodes. The ring electrode of the CIT and both pairs of electrodes in the RIT are divided into more number of parts. Suitable voltages are applied on these parts to improve the linearity of the field. This thesis contains six chapters. Chapter 1 contains a background information about mass spectrometry. Chapter 2 discusses the Boundary Element Method (BEM) used to calculate charge distribution and Nelder-Mead method used for optimization. It also shows the calculation of multipoles. In Chapter 3, two new geometries namely split-electrode RIT and split-electrode CIT are considered with the objective of improving the linearity of electric field inside them. It is shown here that by applying certain external potential on various parts of split electrodes of these geometries, it is possible to improve the linearity of electric field inside them. In Chapter 4, capacitor models of new geometries proposed in chapter 3 are discussed. The use of external capacitors as a replacement to external power supply is also discussed in this chapter. InChapter5, study similar to that ofChapter3is carried out by splitting the geometries in more number of parts. The possibility of improved field profile is investigated by applying full potential to some of these parts and keeping other parts at ground potential. In Chapter 6, concluding remarks are discussed.

The Southeast Asian island of Borneo boasts an incredible diversity of terrestrial mammals which is threatened by habitat loss. Understanding the abundance and distribution of these species is essential for conservation and management. We assessed the occurrence of terrestrial mammals within two commercial forest reserves in Sabah, Malaysian Borneo. In particular, we investigated the habitat associations of the Sunda stink-badger, whose patchy distribution is not well understood. To improve detection probability and precision of model parameters, we deployed 2 camera-traps at sample stations. Our results showed that Sunda stink-badgers are likely dietary and habitat generalists, that may benefit from forest disturbance. Additionally, we found that unguligrade species were associated with high detection probability when data from one camera trap was considered and inclusion of a second camera further increased the detectability of ungulates compared to all other species. We suggest that future studies consider physical characteristics of focal species to maximize effectiveness of camera effort and ensure that data collection is efficient and meets project needs.

<p> A set of scales was created, the "Modified Conibear Scales" which can be used as a basis of comparison to rate the performance of other traps in the areas of impact energy, closing time and clamping force. Further, a detailed set of secondary non quantitative characteristics was presented.</p> <p> Using the above information, several promising traps were rated in order to assess these scales, give some immediate results and indicate promising traps or trap features. Further work in the field was facilitated by providing a detailed experimental procedure, complete lists of data and a calibrated trap for animal research.</p> / Thesis / Master of Engineering (MEngr)

No description available.