Studying nuclei beyond the proton dripline can provide valuable information on the structure of nuclei at the limits of stability, where the strong nuclear force starts to be overcome by Coulomb repulsion between protons. Simple experimental observables, such as excitation energies and lifetimes of excited states in these proton-unbound nuclei can provide information on the nuclear wave function. Experimental data, such as that presented in this work, can then be used to improve models of nuclear structure at the proton dripline. This thesis presents data from a recoil-decay tagged differential plunger experiment undertaken at the University of Jyvaskyla in 2014. A fusion-evaporation reaction was used to populate excited states in the deformed ground-state proton emitter 113Cs. The JUROGAM-RITU-GREAT experimental setup was used to correlate gamma rays emitted from these excited states with protons emitted from 113Cs and the differential plunger for unbound nuclear states (DPUNS) was placed at the target position to measure the excited state lifetimes. The lifetime of the (11/2+) state in the most intense rotational band of 113Cs was measured to be tau = 24(6) ps, while a limit of tau is less than or equal to 5 ps was found for the lifetime of the higher energy (15/2+) state. The lifetime of proton emission was measured to be tau = 24.2(2) microseconds. The experimental data were used to test the predictions of a non adiabatic quasi-particle model for proton-emitting nuclei, which was employed to deduce the deformation of the states in 113Cs. Wave functions from the non adiabatic quasi-particle model were used to independently calculate proton-emission rates, gamma-ray transition rates and excited state energies as functions of deformation. The deformation of 113Cs could then be extracted from the intersection of the different theoretical values and experimental observables. A deformation of beta2 = 0.22(6)was extracted from the (11/2+) excitation energy and lifetime. The deformation values taken from the proton-emission rate and the lifetime limit of the (15/2+) state were also consistent with this value. The consistency of the different deformations calculated shows the effectiveness of the non adiabatic quasi-particle method when used to calculate the properties of deformed ground-state proton-emitters.

Cidades dos países da África Subsariana (SSA) têm passado por um intenso processo de urbanização, implicando em crescimento das atividades econômicas em geral e industriais em particular, assim como, o aumento do tráfego de veículos e da produção de lixo, dentre outras mudanças que afetam diretamente o meio ambiente e a saúde dos habitantes. Neste cenário, a identificação de fontes poluidoras do ar é essencial para a fundamentação de políticas públicas que visam assegurar o direito a uma boa qualidade de vida para a população. Esta pesquisa de Mestrado esteve integrada a um projeto internacional denominado Energy, air pollution, and health in developing countries, coordenado pelo Dr. Majid Ezzati, à época professor da Harvard School of Public Health, e integrando também pesquisadores da Universidade de Gana. Este projeto tinha por objetivo fazer avaliações dos níveis de poluição do ar em algumas cidades de países em desenvolvimento, voltando-se, neste caso particular para Acra (capital de Gana e maior cidade da SSA), e duas outras cidades de Gambia, onde até então inexistiam estudos mais substantivos, relacionando-os com as condições socioeconômicas específicas das diferentes áreas estudadas. Contribuímos com as análises de Fluorescência de Raios X (XRF) e de Black Carbon (BC), com as discussões e interpretações dos dados meteorológicos e no emprego dos modelos receptores. Mas do ponto de vista do aprofundamento de estudos da qualidade do ar e do impacto de fontes, este trabalho concentrou-se na região de Nima, bairro da capital de Gana, Acra. A partir da caracterização do aerossol atmosférico local, empregou-se modelos receptores para identificar o perfil e contribuição de fontes majoritárias do Material Particulado Atmosférico Fino MP2,5 e Grosso MP2,5-10. Foram coletadas 791 amostras (de 48 horas) entre novembro de 2006 e agosto de 2008 em dois locais, na principal avenida do bairro, Nima Road, e na área residencial, Sam Road, distantes 250 metros entre si. A concentração anual média em 2007 para MP2,5 encontrada na avenida foi de 61,6 (1,0) ug/m3 e 44,9 (1,1) ug/m3 na área residencial, superando a diretriz de padrão anual máximo de 10 ug/m3 recomendada pela Organização Mundial de Saúde (OMS). A porcentagem de ultrapassagem do padrão diário (OMS) de 25 ug/m3 foi de 66,5% e 92% para a área residencial e avenida, respectivamente, durante todo experimento. As concentrações químicas elementares foram obtidas por XRF e o BC por refletância intercalibrada por Thermal Optical Transmitance (TOT). Neste trabalho desenvolvemos uma metodologia de calibração do XRF e de intercalibração entre refletância e TOT, baseada em Mínimos Quadrados Matricial, o que nos forneceu incerteza dos dados ajustados e boa precisão nos valores absolutos de concentrações medidos. Análise de Fatores (AF) e Positive Matrix Factorization (PMF) foram utilizadas para associação entre fonte e fator, bem como para estimar o perfil destas fontes. A avaliação de parâmetros meteorológicos locais, como direção e intensidade dos ventos e posicionamento de fontes significativas de emissão de MP auxiliaram no processo de associação dos fatores obtidos por esses modelos e fontes reais. No período do inverno em Gana, um vento provindo do deserto do Saara, que está localizado ao nordeste do país, denominado Harmatão, passa por Acra, aumentando de um fator 10 a concentração dos poluentes relacionados à poeira de solo. Assim, as amostras dos dias de ocorrências do Harmatão foram analisadas separadamente, pois dificultavam a identificação de outras fontes por PMF e AF. As fontes majoritárias indicadas por esses dois métodos (AF e PMF), mostraram-se concordantes: Mar (Na, Cl), solo (Fe, Ti, Mn, Si, Al, Ca, Mg), emissões veiculares (BC, Pb, Zn, K), queima de biomassa (K, P, S, BC) e queima de lixo sólido e outros materiais a céu aberto (Br, Pb) . A redução da poluição do ar em cidades da SSA, caso de Acra, requer políticas públicas relacionadas ao uso de energia, saúde, transporte e planejamento urbano, com devida atenção aos impactos nas comunidades pobres. Medidas como pavimentação das vias, cobertura do solo com vegetação, incentivo ao uso de gás de cozinha e incentivo ao transporte público, ajudariam a diminuir os altos índices de poluição do ar ambiental nessas cidades. / Sub-Saharan Africa (SSA) cities have been intense developing process, resulting in generalized economical activities growing, specially industrial, as well as increase in the vehicular traffic and waste generation, among other changes directly affecting the environment and public health. Therefore, identifying the air pollution sources is an essential issue for public decisions to assure people rights to healthy life. This Master work has been integrated to an international project called Energy, air pollution, and health in developing countries, under coordination of Dr. Majid Ezzati, then at the Harvard School of Public Health, grouping also researchers from the University of Ghana. The aims of this project were to evaluate the air pollution level at some developing countries, by this time devoted to Accra (the capital of Ghana and the main city of SSA), and two other cities of Gambia. Since then, no substantive study was performed there, connecting air pollution to the regional social-economical levels. This Master project, provided the XRF and Black Carbon determination for all samples of the main project, and gave, else, support for meteorological and receptor modeling issues. But concerning the improving of the study of air quality and sources impact, the work focus Nima town, at Accra, the Ghana Capital. The characterization of species in the local atmospheric aerosol was used in Receptor Models to make factor to sources profile association, and respective apportionment in the local PM2.5 and PM10. Between November/2006 and August/2008, 791 filters (sampled for 48 h) collected the local atmospheric aerosol, in two sites separated by 250 m. One was at the main avenue (Nima Road) and other in a residential street (Sam Road). The PM2.5 annual average concentration to 2007 was 61,6 (1,0) ug/m3 near to the avenue and 44,9 (1,1) ug/m3 in the residential area, surpassing ~5 times the Word Health Organization (WHO) guidelines to annual mean (10 ug/m3). Another WHO guideline is not surpass 25 ug/m3 in more than 1% of the samples collected in one year - in each of these sites, 66,5% and 92% of the samples are above this limit. X-Ray Fluorescence (XRF) provided the elemental concentrations, while reflectance, inter calibrated by Thermal Optical Transmittance (TOT), gave the Black Carbon (BC) levels. In this work we performed a methodology for the XRF calibration and for the inter calibration between TOT and reflectance, using Matrix Least Square Fitting that gives the uncertainties of fitted data and improves the precision of the adjusted values. Factor Analysis (FA) and Positive Matrix Factorization (PMF) enabled the association between source and the determined factors, as well as, estimated the sources profile. Local meteorological data, like wind intensity and direction, and the identification of some heavy MP emission sources, helped the process of factors to sources association. During the winter period (January-March), Accra received the Harmattan wind, blowing from Sahara deserts, that increased the concentrations from soil in 10 times. Therefore, the samples from this period were separately analyzed, providing better detection of the other source by PMF and FA. The local main source detected by both methods showed coherency: sea salt (Na, Cl), soil (Fe, Ti, Mn, Si, Al, Ca, Mg), vehicular emissions (BC, Pb, Zn, K) and biomass burning (K, P, S, BC). Reduction of air pollution levels in SSA cities, like Accra, requires public actions providing clean energy sources, health care, public transportation, urban planing and attention to they impact for the poor communities. Relatively simple providences, like roads paving, vegetation covering of the land, use of gas for cooking, public transportation, should decrease the high air pollution level in those cities.

This thesis studies the possibility of using the Monte Carlo simulation program FLUKA to determine the neutron induced radioactivity of concrete walls at the The Svedberg Laboratory (TSL) in Uppsala. If a simulation of the activation would produce reliable results, it would be a useful complement to measurements for the decommissioning and clearance of the buildings of the facility. An experiment was performed in which a concrete core was taken from one of the non-activated walls in the facility. The core was cut into samples and irradiated with a neutron beam. The samples were then measured in a gamma-ray spectroscopy setup, by which the produced radioactive nuclides were identified and their activities determined. The same setup was then simulated in FLUKA. A comparison of the simulations and the measurements shows that the average activity for all nuclides obtained with FLUKA is similar to the measured one, however with large differences for some nuclides. The average ratio of the simulated and measured activities or all nuclides is 1.07 with a standard deviation of 0.55. The obtained results may be useful for future radiological clearance work at TSL.

Soft X-ray spectroscopy is a useful observational tool, offering information about high-temperature (10⁶ -- 10⁷ K) astrophysical plasmas and providing useful characterizations of a number of energetic systems, including accreting young stars, cosmic filaments between galaxies, and supermassive black holes. In order to yield high resolution spectra with good signal-to-noise, however, soft X-ray spectrometers must realize improvements in resolving power and effective area through the development of high performance gratings. Off-plane reflection gratings offer the capability to work at high dispersions with excellent throughput, and are a viable candidate technology for future X-ray spectroscopy missions. The off-plane geometry requires a customizable grating meeting distinct fabrication requirements, and a process for producing gratings meeting these requirements has been developed. These fabricated gratings have been evaluated for performance in terms of resolution and diffraction efficiency. Furthermore, these gratings have been conceptually implemented in a soft X-ray spectrometer, the Off-Plane Grating Rocket Experiment (OGRE), whose optical design provides a template for future missions to achieve high performance within a small payload envelope.

No description available.

<p>Computational methods are combined with synchrotron-based techniques to analyze the structure and bonding of water and water plus hydroxyl at metal surfaces under UHV and at near-ambient conditions. Water-metal interaction plays a crucial role in a multitude of cosmic, atmospheric and biological phenomena as well as heterogeneous catalysis, electrochemistry and corrosion. A spotlight of renewed interest has recently been cast on water-metal systems due to their relevance for surface chemical reactions related to the production and utilization of hydrogen as a clean energy carrier. In particular, H2O and OH are essential reaction intermediates in the renewable production of hydrogen from sunlight and water and in fuel cell electrocatalysis.</p><p>Fuel cells are considered one of the most promising power generation technologies for a sustainable energy future. A mechanistic understanding of the oxygen reduction reaction (ORR) pathway, including the role of electronic and geometric structure of the catalyst, is essential to the design of more efficient fuel cell catalysts. This is intimately connected to fundamental factors that affect the ability to form water-metal bonds as well as the site occupation and orientation of the adsorbed H2O and OH at active metal surfaces.</p><p>Key relationships related to critical issues in the fuel cell reaction are illuminated by the synergy of theory and experiment in this thesis. We emerge with a detailed understanding of the structure of the water-metal interface and the factors that rule the wettability of a metal surface, including geometric and electronic structure effects and the influence of coadsorbed species. We show that the preferred microscopic orientation of the water monolayer has consequences for macroscopic properties, and reveal the origin of the hydrophobic water layer. Finally, we identify a cooperativity effect that drives the stability of the mixed water/hydroxyl layer at metal surfaces, an important ORR intermediate.</p>

<p>Synchrotron-based sulfur spectroscopy reveals a common concern for marine archaeological wood from seawater: accumulation of reduced sulfur compounds in two pathways. The distribution of sulfur species in the oak wood cell structure was mapped by scanning x-ray spectro-microscopy (SXM). Organically bound sulfur was found within lignin-rich parts, identified mainly as thiols and disulfides by sulfur K-edge x-ray absorption near edge structure (XANES) spectroscopy. Particles of iron sulfides, which may form in the presence of corroding iron, appeared in wood cavities. Cores scanned by x-ray fluorescence (XRF) show that high sulfur accumulation is restricted to the surface layers for the Swedish shipwreck <i>Vasa</i>, while the distribution is rather uniform throughout the hull timbers of the <i>Mary Rose</i>, U.K. Laboratory experiments, exposing fresh pine to simulated seabed conditions, show that the organically bound sulfur develop in reactions between lignin, exposed by cellulose-degrading erosion bacteria, and hydrogen sulfide produced <i>in situ</i> by scavenging sulfate reducing bacteria. With bacteria inoculated from shipwreck samples also iron sulfides formed. The iron sulfides oxidise in high humidity, and are the probable main cause of the numerous outbreaks on the Vasa’s hull of acidic sulfate salts, which were identified by x-ray powder diffraction (XRD). The iron ions catalyse several wood-degrading oxidative processes. Multi-elemental analyses were performed by scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (ESCA). The present amounts of total S remaining in the <i>Vasa</i> and the <i>Mary Rose</i> are estimated to at least 2 tonnes. After the <i>Vasa´s</i> spray treatment with polyethylene glycol solutions ceased in 1979, the continuing oxidation processes are estimated to have produced 2 tonnes of sulfuric acid in the wood. Laboratory experiments to gently neutralize acidic <i>Vasa</i> wood by ammonia gas have been conducted with promising results.</p>

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 164-170).

Computational methods are combined with synchrotron-based techniques to analyze the structure and bonding of water and water plus hydroxyl at metal surfaces under UHV and at near-ambient conditions. Water-metal interaction plays a crucial role in a multitude of cosmic, atmospheric and biological phenomena as well as heterogeneous catalysis, electrochemistry and corrosion. A spotlight of renewed interest has recently been cast on water-metal systems due to their relevance for surface chemical reactions related to the production and utilization of hydrogen as a clean energy carrier. In particular, H2O and OH are essential reaction intermediates in the renewable production of hydrogen from sunlight and water and in fuel cell electrocatalysis. Fuel cells are considered one of the most promising power generation technologies for a sustainable energy future. A mechanistic understanding of the oxygen reduction reaction (ORR) pathway, including the role of electronic and geometric structure of the catalyst, is essential to the design of more efficient fuel cell catalysts. This is intimately connected to fundamental factors that affect the ability to form water-metal bonds as well as the site occupation and orientation of the adsorbed H2O and OH at active metal surfaces. Key relationships related to critical issues in the fuel cell reaction are illuminated by the synergy of theory and experiment in this thesis. We emerge with a detailed understanding of the structure of the water-metal interface and the factors that rule the wettability of a metal surface, including geometric and electronic structure effects and the influence of coadsorbed species. We show that the preferred microscopic orientation of the water monolayer has consequences for macroscopic properties, and reveal the origin of the hydrophobic water layer. Finally, we identify a cooperativity effect that drives the stability of the mixed water/hydroxyl layer at metal surfaces, an important ORR intermediate.

Time-dependent molecular properties are important for the experimental characterization of molecular materials. We show how these properties can be calculated, for optical and x-ray frequencies, using novel quantum chemical methods. For xray absorption there are important relativistic effects appearing, due to the high velocity electrons near the atomic nuclei. These effects are treated rigorously within the four-component static exchange approximation. We also show how electron correlation can be taken into account in the calculation of x-ray absorption spectra, in time-dependent density functional theory based on the complex polarization propagator approach. The methods developed have been applied to systems of experimental interest|molecules in the gas phase and adsorbed on metal surfaces. The effects of molecular vibrations have been take into account both within and beyond the harmonic approximation.