Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vii, 62 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 61-62).

Thesis (doctoral)--Rijksuniversiteit te Leiden, 1984. / Includes bibliographical references.

Made available in DSpace on 2014-10-09T12:36:56Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:11Z (GMT). No. of bitstreams: 1 01970.pdf: 15439257 bytes, checksum: 0b1cf3bc75a8883bc2285242fe8dbcfd (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

This dissertation presents a detailed study of many aspects of the Horizontal Branch (HB) phase of stellar evolution. A classical technique of stellar structure analysis is summarized, and applied to Zero-Age Horizontal Branch (ZAHB) models. The chief conclusions from this work are firstly, that the total mass of the envelope sensitively affects the luminosity of the hydrogen-burning shell and the equilibrium of the helium-rich core. Secondly, the rapid progression of models across the Hertzsprung-Russell diagram with decreasing mass is the result of important changes in the hydrostatic structure of the stars. Thirdly, the luminosity-metallicity relationship of the Zero Age models results from the change in the core equilibrium luminosity with the CNO abundance of the shell region, together with the decrease in stellar mass at fixed effective temperature. The change in the mass-temperature relation with CNO is found to be the most important determining factor in the Horizontal Branch stellar distribution, and therefore is the most appropriate ‘first parameter’ for HB morphology. The evolution of the stars is then considered, and the analysis of the interior structures provides a reclassification of HB track morphology into three categories, depending on whether the model contains an outer convection zone or a radiative outer envelope, and on the luminosity of the hydrogen-burning shell. Lastly, the question of the formation of red-giant stars is considered; the general conclusions of this part of the study support the arguments presented by Yahil and van den Horn (1985). Next, the evolution of the convective core of HB stars is reviewed, together with a detailed account of the numerical techniques developed for modelling semi-convection. The problems associated with the late phase of HB evolution are also discussed. A brief review of the physical inputs and numerical methods used in the interior is presented, focussing on the calculation and implementation of the Equation of State. The calculations performed for this study are then presented in detail. The effects of oxygen enhancement on zero-age sequences are illustrated for a range in metallicity, and theoretical relations between luminosity and metallicity for the ZAHBs are demonstrated. The evolutionary tracks computed are illustrated and summarized in extensive tabulations in the Appendices. The final chapter reproduces previously published studies of globular clusters. The first of these investigates the globular cluster NGC104 (47 Tucanae). By fitting the theoretical models to recent CCD photometry of the cluster, it was found that its initial helium content must have been close to 24% by mass. In addition, the best fits show that models for [Fe/H] = -0.65 provide an excellent match to the horizontal branch, if (m - M )v ≈ 13.44, and thereby yield consistency over the entire color-magnitude diagram of the cluster. The second study presents an investigation of the horizontal branch of M15. Detailed matches of our theoretical sequences to the cluster observations indicate that high envelope helium abundances are incompatible with the observed morphology. It is found that there is a clear preference for values of 0.21 ≾ Y ≾ 0.25, independent of the value of [O/Fe]. The precision of the method is reduced by uncertainties in the observations and in the available synthetic temperature-bolometric-correction relations. The oxygen enhanced zero-age HB models are found to have a period-colour relationship which is almost identical to that of their scaled-solar counterparts, but they reduce significantly the predicted double-mode variable masses. Importantly, it is found that, for reasonable assumptions about the reddening to M15, there is no discrepancy between the predicted and observed periods for the RR Lyrae variables. However, the period shift between M3 and M15 can be explained by canonical models only if the helium abundance in both clusters is low (Yhb ~ 0.21), and the bulk of the RR Lyrae star population in M15 is at late stages of evolution. These conclusions are reconsidered in the light of the new calculations presented here. / Graduate

abstract: Using high-resolution three-dimensional adaptive mesh refinement simulations I study the interaction between primordial minihalo, a clump of baryonic and dark matter with a virial temperature below the atomic cooling limit, and a galaxy outflow. In Chapter 2 I concentrate on the formation of molecular coolants and their effect on the evolution of the minihalo gas. Molecular coolants are important since they allow gas to cool below 10000 K. Therefore, I implement a primordial chemistry and cooling network that tracks the evolution and cooling from these species. I show that the shock from the galaxy outflow produces an abundance of coolants in the primordial gas which allows the gas to cool to below 10000 K. I also show that this interaction produces compact stellar clusters that are ejected from their parent dark matter halos. In Chapter 3 I look at the turbulent mixing of metals that occur between the minihalo and outflow. To do this, I develop a sub-grid model for turbulence that reproduces three primary fluid instabilities. I find that the metals from the outflow are well mixed throughout the minihalo gas. In addition, the metal abundance found roughly corresponds to the observed abundances in halo globular clusters. In Chapter 4, I conduct a suite of simulations that follow this interaction over a wide range of parameters. In almost all cases, the shocked minihalos form molecules and cool rapidly to become compact, chemically homogenous stellar clusters. Furthermore, I show that the unique properties of these clusters make them a prime observational target for study with the next generation of telescopes. Given the unique properties of these clusters there are reasons to suspect that their low-redshift counterparts are halo globular clusters. I outline this comparison in Chapter 5 and give my conclusions in Chapter 6. Finally, I summarize my current work in Chapter 7 and future extensions in Chapter 8. By the end, I hope to convince you that the interaction between a galaxy outflow and a primordial minihalo provides a formation pathway for present day halo globular clusters. / Dissertation/Thesis / Ph.D. Astrophysics 2012

This thesis attempts to test several frameworks of non-Newtonian gravity in the context of galaxies and galaxy clusters. The theory most extensively discussed was that of Modified Newtonian Dynamics (MOND) with Galileon gravity, Emergent Gravity (EG) and Modified Gravity (MOG) mentioned to a lesser extent. Specifically, the main focus of this thesis was to determine whether MOND and MOND-like theories were compatible with galaxy cluster data, without the need to include cold dark matter. To do this, the paradigms of Extended MOND (EMOND), Generalised MOND (GMOND) and superfluid dark matter were investigated. The theories were outlined and applied to galaxy cluster data. The main findings of this were that EMOND and GMOND had some success with explaining galaxy cluster mass profiles, without requiring an additional dark matter component. The superfluid paradigm also enjoyed some success in galaxy clusters, which was expected as it behaves in a similar manner to the standard cold dark matter paradigm in cluster environments. However, the superfluid paradigm may have issues in the very centre of galaxy clusters due to the theory predicting constant density cores, whereas the cold dark matter paradigm predicts density cores which are cuspier. The EMOND paradigm was also tested against ultra-diffuse galaxy (UDGs) data as they appear in cluster environments, where EMOND becomes important. It was found that EMOND can reproduce the inferred mass of the UDGs, assuming they lie on the fundamental manifold (FM). The validity of the assumptions used to model the UDGs are discussed in the text. A two-body problem was also conducted in the Galileon gravity framework. The amount of additional gravitational force, compared to Newtonian was determined for a small galaxy at the edge of a galaxy cluster.

MESQUITA, B. A. de. Análises fisico-químicas e isotópicas para identificar os principais processos de salinização de águas subterrâneas em Dunas e Cristalino (Caucaia-CE). 2017. 124 f. Tese (Doutorado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Pós-Graduação em Física (posgrad@fisica.ufc.br) on 2017-10-20T19:22:00Z No. of bitstreams: 1 2017_tese_bamesquita.pdf: 8673974 bytes, checksum: 58a8a49e9ba507d41d99adb1c7b0e888 (MD5) / Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-10-26T20:17:13Z (GMT) No. of bitstreams: 1 2017_tese_bamesquita.pdf: 8673974 bytes, checksum: 58a8a49e9ba507d41d99adb1c7b0e888 (MD5) / Made available in DSpace on 2017-10-26T20:17:13Z (GMT). No. of bitstreams: 1 2017_tese_bamesquita.pdf: 8673974 bytes, checksum: 58a8a49e9ba507d41d99adb1c7b0e888 (MD5) Previous issue date: 2017 / The main aim in this work was to find the most important groundwater salinization processes, in two hydrogeologically distinct regions (Caucaia, Ceara´, NE-Brazil); one in the coast, where Dunes and Barreiras Formation predominate, and another 20 km from shoreline (inland), a crystalline basement area. Groundwater samples of 39 wells, 27 from the coast and 12 from the inland, were collected in March/14, February/15 and August/15 to analyze physicochemical and isotopes parameters. Using the average value of the three sampling campaigns, it was concluded that the different ranges of electrical conductivity values separate the groundwater from the two regions. Piper diagram reflected the different types of water, Na-Cl-type for the inland and Na-Ca-HCO3 for the coast. About potable water, 11 coastal samples had the NO− 3 concentration above that allowed for drinking-water quality, indicating anthropogenic effects, and inland, the most samples has high salinity. Statistical analysis clustered the wells according to their salinity. Gibbs diagram showed weathering dominance in both regions, as well as the evaporation process, inland. Gaillardet diagram identified: silicate weathering in both regions, but in different level; slight carbonate weathering, in the coast; and evaporite weathering, inland. Ionic ratios suggested plagioclase alteration and calcite dissolution for the coastal samples, the molar transfer was obtained by NETPATH; marine aerosols contribution and ferromagnesian minerals alteration for the inland samples, which also presented orographic influence. The relationships δ18O - δD evidenced processes of evaporation, during the recharge, in the two areas, by rainwater; d-excess showed that coastal samples suffer a greater evaporation process. Measures of δ13C showed the influence of the soil in inland samples, while in the coast, where the recharge is faster, the waters have a less interaction with the soil during the recharge. Inland, pMC data and age corrections have ensured that the waters are from recent recharges. / Este trabalho trata dos processos, mais relevantes, de salinização de águas subterrâneas coletadas em poços localizados em duas áreas hidrogeologicamente distintas no município de Caucaia/CE; uma na costa, onde predomina a Formação Dunas, e outra, 20 km da linha costeira, no interior, uma área de embasamento cristalino. As amostras de 39 poços, 27 da costa e 12 do interior, foram coletadas em Março/14, Fevereiro/15 e Agosto/15 para analisar parâmetros físico-químicos e isotópicos. Usando o valor médio das três campanhas, concluiu-se que diferentes faixas de valores de condutividade elétrica separam a água subterrânea das duas áreas. O diagrama de Piper mostrou os diferentes tipos de água, Na-Cl no interior e Na-Ca-HCO3, na costa. Quanto a qualidade, concentrações de NO-3 acima do VMP identificaram contaminação antrópica em 11 amostras na costa e01 no interior, que tem, na maioria das amostras, águas impróprias para o consumo humano, devido ao alto teor de sal, com concentrações Na+ e Cl- acima do VMP. A análise estatística agrupou os poços de acordo com a salinidade, polarizando as duas áreas. O diagrama de Gibbs mostrou que há intemperismo nas duas áreas e processo de evaporação, no interior. Do diagrama Gaillardet foram identificados intemperismo de silicatos nas duas áreas, mas em diferentes intensidades; além de dissoluções de carbonatos, na costa, e de evaporitos, no interior. As razões irônicas, das amostras da costa, sugeriram alteração de plagioclásio para caolinita e leve dissoluções de calcita e biotita, os valores das transferências molares entre água e rocha foram obtidos pelo software NETPATH; no interior, sugeriram a contribuição dos aerossóis marinhos e intemperismo de minerais ferromagnesianos, produzindo alta salinidade, influenciada também pela orografia local. As relações δ18O - δD evidenciaram processos de evaporação, durante a recarga, nas duas áreas, por águas de chuvas; d-excesso mostrou que as amostras da costa sofrem um maior efeito de evaporação em relação as do interior. Medidas de δ13C mostraram a influência do solo no interior, enquanto na costa, onde a recarga é mais rápida, as águas tem uma menor interação com o solo durante a recarga. No interior, dados de pMC e correções de idades garantiram que as águas são de recargas recentes.

BRAGA, Antonio Rafael. ElasticCluster: explorando a ociosidade de clusters virtuais para execução de Aplicações do tipo saco de tarefas. 2012. 91 f. Dissertação (Mestrado em Engenharia de Teleinformática) - Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2012. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2015-09-21T13:51:59Z No. of bitstreams: 1 2012_dis_arbraga.pdf: 4307313 bytes, checksum: 234b4e9abc3b4387f1bb12929b55e906 (MD5) / Approved for entry into archive by Aline Mendes(alinemendes.ufc@gmail.com) on 2015-09-21T14:50:37Z (GMT) No. of bitstreams: 1 2012_dis_arbraga.pdf: 4307313 bytes, checksum: 234b4e9abc3b4387f1bb12929b55e906 (MD5) / Made available in DSpace on 2015-09-21T14:50:37Z (GMT). No. of bitstreams: 1 2012_dis_arbraga.pdf: 4307313 bytes, checksum: 234b4e9abc3b4387f1bb12929b55e906 (MD5) Previous issue date: 2012 / In cloud computing, elasticity and capacity of load isolation allow their resources to be provisioned and released in response to dynamic workloads with reduced downtime. These characteristics are typical of clusters hosted in a cloud (virtual cluster - VC), so that these resources need to be managed in order to minimize its waste in cloud providers and ensure that resource performance is not adversely affected. This work proposes a policy for dynamic adaptation of virtual clusters (VCs) to reduce the number of idle resources without compromising their performance of resources. The proposed algorithm, based on heuristics, performs instantiation/shut-down of the virtual machines (VMs) in virtual clusters according variation in demand for resources of applications of type Bag-of-Tasks, BoT. The algorithm has been specified, verified and validated using Petri Nets formalism. The selected metrics to evaluate the proposal performance in three different scenarios are the total amount of machine started, amount of idle machines reused, total time of execution the application and average number of clusters started. The results showed that the adaptation policy proposal is able to reduce idle and the overhead of a virtual cluster and thus improve power consumption. / Na computação em nuvem, a elasticidade e a capacidade de isolamento de carga permitem que seus recursos sejam aprovisionados e liberados em resposta a cargas de trabalho dinâmicas com baixo tempo de inatividade. Tais características são típicas de clusters hospedados em nuvem (cluster virtual - CV), de tal forma que estes recursos precisam ser gerenciados a fim de se garantir a minimização do desperdício de recursos nos provedores e garantir que o desempenho dos recursos não seja afetado negativamente. Este trabalho propõe uma política para adaptação dinâmica de clusters virtuais (CVs) a fim de reduzir o número de recursos ociosos sem comprometer o desempenho dos serviços. O algoritmo proposto baseado em heurística, realiza instanciação e desligamento de máquinas virtuais nos CVs conforme variação na demanda por recursos de aplicações do tipo saco de tarefas (Bag-of-Tasks, BoT). O algoritmo foi especificado, verificado e validado através de simulações em Redes de Petri (RdP). O desempenho da proposta é avaliado em três cenários distintos a partir das métricas: quantidade total de máquinas iniciadas, quantidade de máquinas ociosas reutilizadas, tempo total de execução da aplicação e quantidade média de clusters iniciados. Os resultados mostraram que a política de adapta¸c˜ao proposta ´e capaz reduzir a ociosidade e a sobrecarga de um CV e, consequentemente, melhorar o consumo de energia.

Made available in DSpace on 2014-06-11T19:26:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-08Bitstream added on 2014-06-13T19:54:27Z : No. of bitstreams: 1 oliveira_kf_me_bauru.pdf: 752377 bytes, checksum: 08030a272b4d29b46db7b192cc61e943 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As instabilidades econômicas que envolvem o setor industrial fazem com que as empresas busquem novas formas de organização que permitam agregar vantagens. A aglomeração de empresas do mesmo setor e com atividades correlatas é chamada de cluster industrial. Neste contexto, as Micro e Pequenas Empresas (MPEs) podem alcançar algumas vantagens competitivas que individualmente não conseguiriam, por meio de ações coletivas fomentadas por uma governança estruturada. O estudo de clusters permite investigar o processo de implantação das tecnologias de gstão que podem auxiliar na obtenção da eficiência coletiva, do fornecimento da cooperação empresarial, da criação de vantagens competitivas e na promoção do crescimento econômico, social e local. Desta forma, o objtetivo desta pesquisa é desenvolver diretrizes de práticas para a transferência de tecnologia de gestão entre clusters, de forma que promova a cooperação empresarial e o desenvolvimento sustentável. Foi realizada uma revisão bibliográfica dos principais temas e um estudo de caso no cluster metal-mecânico de Sertãozinho - SP, por meio de entrevistas semi-estruturadas com os agentes de governança, a fim de ambientar o pesquisador e identificar algumas iniciativas que corroboram e contribuem com ações coletivas propostas na literatura. Os resultados desta pesquisa englobam as diretrizes de práticas de gestão organizadas em um processo de 8 etapas: Diagnóstico Inicial, Diagnóstico 2, Planejamento Macro, Planejamento Detalhado, Preparação para a mudança, Implantação, Medição e Controle e Ação/Retroalimentação, desenvolvidas a partir da fundamentação teórica e refinadas por meio da experiência de Sertãozinho / Ahead of the economic instability involving the industrial and business competitivess, which causes companies to seek new forms of organization that give advantages. Firms agglomerateds within the same sector and with complementary activities is called industrial cluster. In this context, the Micro and Small Enterprises (MSEs) can to achieve some competitive advantages that could not be reached indivivually, through collective actions forested by a governance structure. Cluster study allows investigating the process of implementation of management technologies that can assist in achieving collective efficiency, strengthening business cooperation, competitive advantages creation and growth economic, social and local promotion. In this way, the objective of this research is to develop practice guidelines for guidelines for management technology transfer between clusters in order to promote business cooperation and sustainable development. It was performed a literature review of key issues and a case study in Sertãozinho - SP cluster metal-mechanic, through semi-structured interviews with the governance agents, in order fit in the researcher and identify some initiatives that support and contribute to collective actions proposed in the literature. The results of this research include guidelines for management practices organized in a eight steps process: Initial Diagnosis, Diagnosis 2, Macro Planning, Detailed Planning, Preparation for the change, Implementation and Action/Feedback, developed from the theoretical and refined through of Sertãozinho experience

Made available in DSpace on 2013-08-07T19:08:18Z (GMT). No. of bitstreams: 1 000449211-Texto+Parcial-0.pdf: 158484 bytes, checksum: 16db88bea9b358e2895521faa0ba81c3 (MD5) Previous issue date: 2013 / TBI individuals may present great functional disability. Most of these dysfunctions is related to clinical manifestations of cognitive impairment, which creates several losses in different areas, such as work, autonomy and, as a consequence, on the quality of life of individuals and their relatives. In this context, studies have discussed the heterogeneity of clinical manifestations in TBI, which challenges research of clinical trials and characterization studies as a whole. One of the main issues in the field of clinical and cognitive neuropsychology is the understanding of executive functions (EF) post-TBI and their neural correlates. For this reason, it is of great interest to integrate neuropsychological evaluation, classical methods of clinical neuropsychology and neuroimaging. This dissertation aimed to investigate EF in TBI individuals by means of two studies. The first study investigated the profile of executive functioning in a sample of TBI individuals. This study included an extensive neuropsychological evaluation with a primary focus in FE. Results showed three different profiles of FE: Cluster 1 was characterized by difficulties in processing speed, phonemic verbal fluency and inhibition; Cluster 2 was formed by multiple deficits in FE, such as processing speed, working memory, planning, cognitive flexibility and verbal fluency; finally Cluster 3 had no or very mild difficulties on the EF examined.The second study investigated the two cases of adults with mild TBI with different education levels on EF performance and brain structures volumetry and cortical thickness. The patient with high education surpassed the patient with low education in four variables of FE and different structures of brain volume and cortical thickness. The results suggest that education seems to be a feature of cognitive reserve in mild TBI. Together, these studies contribute for answers to an important question about heterogeneity of TBI and clinical studies. Our findings reinforce the importance of group interventions constituted according to sociocultural variables and cognitive profiles, rather than sociocultural, individual and clinical variables. However, when considering case analysis, sociocultural variables seem to be important for cognitive performance and brain reorganization in mild TBI. / Os indivíduos que sofrem TCE podem ter grande incapacidade funcional. A maior parte dessas disfunções tem relação com manifestações clínicas de prejuízos cognitivos, o que cria diversas perdas em diferentes áreas, tais como, trabalho, autonomia e como conseqüência uma qualidade de vida não apenas o indivíduo, mas também todos aqueles que estão envolvidos com ele. Neste contexto, os estudos têm discutido a heterogeneidade das manifestações clínicas do TCE, ainda um grande desafio em ensaios clínicos e estudos de caracterização como um todo. A maior lacuna na área de neuropsicologia clínica e cognitiva é a compreensão das funções executivas (FE) pós-TCE e de seus correlatos neurais. É de grande interesse integrar a avaliação neuropsicológica, os métodos clássicos clínicos da neuropsicologia, e técnicas avançadas de neuroimagem. A presente dissertação visou ainvestigar FE no contexto clínico do TCE. Dois estudos foram realizados nesta dissertação. O primeiro estudo avaliou o perfil de funcionamento executivo de uma amostra de TCE. Este panorama executivo foi baseado em uma extensa avaliação neuropsicológica com foco principal em FE. Os resultados apontaram três perfis diferentes de FE: o Cluster 1 foi caracterizado por dificuldades em velocidade de processamento, fluência verbal fonêmica e inibição; o Cluster 2 foi formado por múltiplos déficits em FE, tais como, de velocidade de processamento, memória de trabalho, planejamento, flexibilidade cognitiva e fluência verbal; finalmente o Cluster 3 não apresentou dificuldades executivas objetivamente examinadas. O segundo estudo investigou o desempenho em tarefas de FE e índices de volumetria e de espessura cortical em regiões de interesse por seu correlato com FE em dois casos de adultos com TCE leve com diferentes escolaridades.O paciente com alta escolaridade superou o paciente de baixa escolaridade em quatro variáveis das FE e em diferentes estruturas de volume cerebral e espessura cortical. Os resultados sugerem que a educação parece ser uma característica de reserva cognitiva no TCE leve. Juntos, esses estudos contribuem com respostas a uma pergunta importante sobre possíveis soluções para a heterogeneidade neuropsicológica do TCE. Nossos achados reforçam a relevância de intervenções em grupo constituído de acordo com variáveis socioculturais e perfis cognitivos. Para a formação de subgrupos clínicos de TCE, seu funcionamento executivo parece ser sido a principal variável, na medida em que não houve diferenças quanto a fatores socioculturais,m individuais nem clínicos. No entanto, quando se considera análise de casos, variáveis socioculturais parecem importantes para o desempenho cognitivo e para a reorganização cerebral no TCE leve.