Orientador: Jose Bellandi Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-17T21:06:46Z (GMT). No. of bitstreams: 1 Pavao_HamiltonGermano_M.pdf: 627144 bytes, checksum: 4ba361d4b2336585984f7a2aae450ccb (MD5) Previous issue date: 1983 / Resumo: Utilizando-se o operador de evolução temporal e o método de ordenação temporal, calcula-se os propagadores para uma partícula livre e para o oscilador harmônico. Estabelece-se, também, a conexão entre um propagador para um potencial bidimensional tipo 1/r e o propagador do oscilador harmônico bidimensional. Através de uma transformação adequada de coordenadas, transforma-se o operador de evolução temporal para o problema do potencial 1/r em um operador de evolução temporal para o oscilador harmônico, onde a determinação do propagador é feita, utilizando-se a técnica de ordenação temporal. Demonstra-se, também, um teorema de adição para as funções associadas de Legendre / Abstract: Utilizing the operator of temporal evolution and the method of time ordering, the propagators for a free particle and for a harmonic oscillator are calculated. Also, a connection between the propagator for a bi-dimensional potential of the type 1/r and a propagators of a bi-dimensional harmonic oscillator is established. Through na adequate transformations of coordinates, the operator of temporal evolution for a problem with a potential 1/r transformed into na operator of temporal evolution for a harmonic oscillator where determination of the propagator is done utilizing the technique of time ordering. Also, na addition theorem, for the associated Legendre functions is demonstrated. / Mestrado / Física / Mestre em Física

Orientador: Mario Eusebio Foglio / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-19T15:06:53Z (GMT). No. of bitstreams: 1 Silva_MarcosSergioFigueirada_D.pdf: 2518915 bytes, checksum: 9a2d5342bfe9cc62a6d4422e9b8bdb9c (MD5) Previous issue date: 1994 / Resumo: Estendeu-se para o Modelo de Anderson Periódico (MAP), uma expansão diagramática em cumulantes, empregada por Hubbard para estudar seu modelo de banda estreita de elétrons fortemente correlacionados. O modelo também foi estendido para considerar estados eletrônicos localizados, com um esquema arbitrário de níveis de energia, que é útil para estudar compostos de valência intermediária como o Eu ou o Tm. Foram derivadas regras para o cálculo do potencial grand canônico e para as Funções de Green (FG) do modelo geral. Nesses cálculos, só aparecem diagramas conectados e as somas sobre os sítios da rede não são restritas. Para gerar as médias cumulantes, é necessário usar os campos externos "fictícios" de Grassmann x. É apresentado um modo simples de estender as regras diagramáticas para o caso em que os campos x são diferentes de zero. A expansão cumulante foi aplicada ao MAP, para uma banda de condução retangular e para uma banda de condução de largura zero (limite atômico), no caso de repulsão infinita entre dois elétrons localizados no mesmo sítio (U = ¥). Foram efetuados cálculos das funções de Green para duas famílias diferentes de diagramas na fase paramagnética: 1) A Aproximação de Cadeias (AC), empregando somente cumulantes de segunda ordem, 2) Aproximação dos Múltiplos Anéis (AMA) que, além das cadeias, considera anéis simples fechados de todos os tamanhos, mas com, no máximo, cumulantes de quatro tempos. Foram calculados a partir das FG, os números de ocupação dos elétrons localizados e dos elétrons de condução, por sítio e por "spin". A falta de completeza e a não analiticidade das FG fora do eixo real foram discutidas e apresentamos novos modos de tratar esses problemas. Foram estudadas as aproximações F -deriváveis. Foi mostrado que a AC é uma F -derivável "exata", no qual a única aproximação usada foi a escolha dos diagramas para o cálculo do funcional F , usado para calcular as FG. Do estudo da AC fica claro que as aproximações F -deriváveis não resolvem o problema da falta de completeza das FG no espaço dos números de ocupação f. Também estudamos uma F -derivável que é uma extensão da AMA, mas, nesse caso, é necessário efetuar uma aproximação adicional que limita os cumulantes usados na aproximação somente até quarta ordem. Neste último caso, os cálculos numéricos foram efetuados somente para o limite atômico, porque o cálculo para a banda larga exige um longo tempo de computação, e a partir dos resultados atômicos, não esperamos que essa aproximação resolva o problema da completeza. Na etapa final dessa pesquisa, foi descoberta uma técnica que resolve o problema da completeza no contexto dos operadores X de Hubbard e apresentamos uma conjectura geral que foi verificada em todos os casos considerados. Foram dados resultados para duas dessas aproximações, tanto para o limite atômico quanto para a banda / Abstract: The diagrammatic expansion in cumulants that was employed by Hubbard to study his model of a narrow band of strongly correlated electrons was extended to the Periodic Anderson Model (PAM). The model was also extended by considering localized electronic states with an arbitrary scheme of energy levels: this extension would be useful to study intermediate valence compounds of Eu or Tm with the present formalism. The rules for the diagrammatic calculation of the grand canonical potential and of the Green's functions (GF) for the general model have been derived: only connected diagrams appear in those calculations, and the lattice sums are unrestricted. To generate the cumulant averages it was necessary to employ external fields x that are Grassman variables and it is presented a simple way to extend the diagrammatic rules for the x ¹ 0 case. The cumulant expansion was applied to the P AM for a wide rectangular band of conduction electrons (wide band) and for a conduction band of zero width (atomic limit), in the case of an infinite repulsion between two localized electrons at the same site (U = ¥). Two different families of diagrams were considered to calculate the one-particle GF in the paramagnetic phase: 1) the chain approximation (CHA) employing only second order cumulants, 2) the multiple loop approximation (MLA), that also considers rings of all sizes, but employs at most fourth order cumulants. The occupation numbers per site and per spin of the localized electrons (nf) and of the conduction electrons (nc) are obtained from the GF, and the lack of completeness in the space of localized electrons and the non-analyticity of the GF off the real axis are discussed: new approaches to treat these two problems are presented. The F-derivable approximations were also employed. It was possible to show that CHA is a F-derivable approximation, in which the only approximation is the choice of the diagrams employed to calculate the functional F , from which the GF can be obtained. It was then clear that the F-derivable approximations do not solve the lack of completeness. We have also studied a F-derivable extension of the MLA, but in this case it was necessary to add a further approximation, namely to restrict the cumulants employed to fourth order only. In this last case the numerical calculations were only performed in the atomic limit, because the wide band case would require a rather long time of computation, and from the results in the atomic limit we did not expect that this approximation would solve the completeness problem. In the final stages of the present work a technique that solve the completeness problem in a context of X Hubbard operators was discovered. A general conjecture, that has been verified in alI the cases we considered, is presented. The numerical results for two of these approximations, both for the wide band and for the atomic limit, are given / Doutorado / Física / Doutor em Ciências

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With rapid growth and pervasive usage of internet and information technology, information assurance and security has become the top most challenging issues for many organizations. Security professionals and experts have been striving hard to protect the computers, information and centralized network system. These security risks increase more when information is held outside the internal computing environment. Additionally, IT industries are recently pushed by environment regulation to reduce the CO2 footprint of information technology system, production and processes lines. According to recent statistics IT industry is responsible of generating 3% of carbon footprint (Frangiskatos, Ghassemian and Diane, 2010) through their massive consumption of energy. One of the solutions to reduce the energy consumption by Information Communication Technology (ICT) is introduction of Green IT solutions such as Virtualization, thin client, cloud computing, paper reduction, on-line communication system, travel reduction and computer recycling. These Green IT efforts have many green benefits and leading a change in IT processes and system for the protection of environment. But the efforts to reduce, energy consumption, efficient utilization of resources and electronic waste (e-waste) and change in IT may put the system and information on risk if “Green IT” initiatives and solutions are not reviewed from an Information Assurance perspective. As a result it can impact the continuity of business and its assets. This thesis provides a literature review on Green IT from information assurance and security perspective. The purpose of thesis is to assess how Green IT could be threat to security. Its key areas of focus on information assurance and security threats and risks in Green IT solutions which are being promoted for environmental protection. Thesis also highlights the vulnerabilities in Green IT solutions. Thesis presents security challenges of Green IT, need to focus, towards the goal of secure Green IT. While thesis does not discuss any specific defense mechanism, it provides a path for future research in this domain. I believe that thesis work points towards an interesting and important area in Green IT security. / <p>Validerat; 20121129 (global_studentproject_submitter)</p>

Theanine is a free, non-protein amino acid found in Camellia sinensis (tea) leaves. It is the main amino acid component in tea and contributes 1 to 2% of the dry weight of tea leaves. The content of amino acids is a key green tea quality parameter. High grade teas contain high amounts of theanine. It is responsible for the sweet, brothy umami taste of green tea. To date there is no international standard method for the analysis of theanine in tea samples. Several methods with different advantages and disadvantages have been reported but most of them are unsuitable for routine quality control analysis in commercial tea samples. In this study, a high performance liquid chromatography (HPLC) method with evaporative light scattering detection for the determination of theanine in tea samples has been developed. Chromatographic separation of theanine was achieved by reverse phase HPLC using a phenyl-hexyl column and isocratic water elution within 8 minutes. The method requires no sample derivatization and includes simple sample clean-up. Applying the same chromatographic conditions to a widely available C18 column, separation of theanine was achieved within 10 minutes. The successful application of the C18 column renders this method widely applicable. The method is linear over several orders of magnitude and the LOD are 11.53 and 10.83 μg/ml and the LOQ are 39.44 and 35.10 μg/ml for the phenyl-hexyl and C18 column, respectively. Simple but effective sample preparation and polyvinylpolypyrrolidone pre-treatment, along with the short analysis time facilitates high sample throughput (~40 samples can be prepared in an 8 hour day with overnight analysis by HPLCELSD). The method is selective, precise, accurate and practical for the quantification of theanine in tea extracts and was successfully used to determine theanine content in a variety of tea samples. The sensitivity and simplicity of this method renders it suitable for use in routine theanine analysis in quality control laboratories. Green tea, a simple refreshing beverage, has been believed to have therapeutic uses for centuries. Scientists have recognized that the wide range of physiological functions of green tea is due to the presence of catechins. An increasing body of evidence is showing that methylated forms of catechins have potent inhibitory activities to allergies. In addition to the methylated catechins, another relative novel group of catechins exists, namely digallated catechins. The medicinal value of these compounds is not yet known, but it is reasonable to speculate that the antioxidant capacity of digallated catechins will be superior to that of epigallocatechin gallate due to the 3 additional hydroxyl groups provided by the second gallic acid moiety. In this study reverse phase UPLC/ESI-MS/MS was effectively applied to investigate the presence of digallated and methylated catechins in crude tea extract. Low abundance catechins (-)-epigallocatechin-(O-3”-methyl) gallate ([M + H]+, m/z 473) and (-)-epicatechin-3-(O-3”-methyl) gallate ([M + H]+, m/z 457) were successfully detected at 31.9 and 37.5 minutes, respectively. The 2 digallated catechins investigated could not be detected, possibly due to being present at concentrations below the limit of detection. Compared to conventional HPLC/ESI-MS/MS, increased resolution and sensitivity, 80% less use of solvent and significantly reduced analysis times were observed. / Dissertation (MSc)--University of Pretoria, 2009. / Biochemistry / unrestricted

Membranes are a robust, reliable and economical technology. However, polymeric membranes are manufactured from polymeric and organic solvent sources derived from petrochemical sources. The high volatile organic compounds (VOC) emissions of the organic solvents and the non-recyclability of the polymers often question the membrane manufacture sustainability. The main goal of this dissertation is the preparation of polymeric membranes for liquid separation through more sustainable processes. We report here the green preparations of hollow fibers, thin-film composite and integrally skinned asymmetric membranes. An important part of the work is represented by the development of cellulose hollow fibers from ionic liquid solutions, avoiding strong alkali or harsh solvents. By tuning the manufacturing process, we prove that the membranes can be used for different applications such as oil-water separation, protein separation via ion-exchange chromatography and solvent purification via organic solvent nanofiltration. The main advantages of using cellulose to prepare hollow fiber membranes are the biodegradability of the polymer and the intrinsic chemical stability. Another significant milestone of this work is replacing volatile solvents such as hexane during the thin-film composite membrane manufacture. As green alternative solvents, we decided to use naturally extracted oleic acid and decanoic acid. Due to their low costs and volatility, they represent a valid alternative for industrial membrane preparation through the interfacial polymerization process. The membranes prepared with this process were used for solvent resistant nanofiltration. Finally, by using ionic liquids as solvents, we improved the manufacturing sustainability polytriazole asymmetric membranes synthesized in the lab.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Lima’s Villa El Salvador is one of the cities of Peru with the highest population growth rate in recent decades, and still it is needing to develop many urban infrastructure services. However, this process of urbanization has also produced a decrease in the permeability of the terrain causing in recent years flooding and severe damages by the occurrence of heavy rains in the district. It was proposed the implementation of a sustainable urban drainage system (SUDS) to provide an engineering solution to this problem. It consists of a set of elements of the drainage network that will allow the collection, transport, retention, infiltration, and rainwater evacuation sustainably. Four SUDS alternatives were analyzed using well-founded methodologies to select the best alternative solution for the existing problem using technical, economic, and environmental criteria. The implementation of a retention tank and green ditches is the solution adopted to reduce the risk of flooding because of urbanization in the studied area. Runoff from the upper part of the basin will be collected through the green ditches, and the collected water will be distributed to increase the green spaces of the district. However, it will be necessary to supplement with irrigation to preserve them since this locality is climatologically arid. Successful storm water management requires integration with the urban and regional development plans.

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