Neste trabalho são analisados os quatro modos de plasmon, ligados simétrico (Sb) e assimétrico (ab), fuga pelo núcleo (ln) e fuga pela cobertura (lc), que se propagam em uma fibra óptica fracamente guiada envolta por um filme metálico. No filme metálico é depositada uma camada dielétrica extra e acima desta, uma outra denominada cobertura. A análise será desenvolvida para filmes metálicos de prata, paládio e ouro. Esta estrutura é muito útil na confecção de sensores ópticos. / In this work the four Plasmon modes are analyzed, the symmetrical (Sb) and asymmetrical bounded (ab); the core (ln) and covering leaky modes (lc), that propagate in weakly guided optical fibers with a metallic film around that. In the metallic film a layer extra dielectric is deposited and above this, another layer denominated covering. The analysis will be developed for metallic films of the Silver, Palladium and Gold. This structure is very useful to making optical sensors.

Le but principal de cette thèse était de calculer les spectres de dichroïsme circulaire magnétique de rayons~X au seuil K afin de fournir un outil pour interpréter les spectres expérimentaux, jusqu'ici très déroutants. La détermination du dichroïsme circulaire nécessite le calcul précis des spectres d'absorption des rayons~X polarisés circulairement. Nous avons constaté que la théorie des perturbations semi-classique dépendante du temps, communément utilisée pour calculer les sections efficaces d'absorption et de diffusion, est incompatible à la fois, avec l'invariance de jauge et avec les descriptions semi-relativistes de la dynamique des électrons. Pour résoudre ces problèmes, on applique une transformation de Foldy-Wouthuysen aux sections efficaces relativistes données par l'électrodynamique quantique. Ainsi, un nouveau terme d'interaction lumière-matière émerge, que nous avons appelé "spin-position". Une approche performante a été développée pour calculer la section efficace d'absorption afin d'obtenir le dichroïsme circulaire magnétique de rayons~X (XMCD) et le dichroïsme circulaire naturel de rayons~X (XNCD). La méthode numérique repose sur la théorie de la fonctionnelle de la densité en ondes planes avec des pseudopotentiels. Nous constatons que le terme couplant l'opérateur dipolaire électrique avec l'opérateur spin-position contribue significativement au XMCD au seuil K du fer, du nickel et du cobalt ferromagnétiques et nous l'expliquons grâce aux règles de somme. Nous avons également appliqué la méthode aux calculs du XMCD dans FeH et CrO2. Dans les deux cas, la combinaison de l'expérience et de la théorie conduit à un enrichissement mutuel. / The main purpose of this thesis was to compute X-ray magnetic circular dichroism spectra at the K-edge in order to provide a tool to interpret the, so far very puzzling, experimental spectra. Computation of circular dichroism requires precise calculations of X-ray absorption spectra (XAS) for circularly polarized light. We have found that there is an incompatibility of the semi-classical time-dependent perturbation theory commonly used to calculate light absorption and scattering cross-sections with both gauge invariance and semi-relativistic descriptions of the electron dynamics. The problems are solved by applying a Foldy-Wouthuysen transformation to the fully relativistic cross-sections given by quantum electrodynamics. In the process, a new light-matter interaction term emerges, that we named the "spin-position" interaction. An efficient first-principles approach was developed to compute the absorption cross-section in order to obtain X-ray magnetic circular dichroism (XMCD) and X-ray natural circular dichroism (XNCD). The numerical method relies on density-functional theory with plane waves and pseudopotentials. We find that the term coupling the electric dipole operator with the spin-position operator contributes significantly to the XMCD at the K-edge of ferromagnetic iron, cobalt, and nickel. We obtain a sum rule relating this term to the spin magnetic moment of the p states. We also applied the method to calculations of K-edge XMCD in FeH and CrO2. In both cases, the combination of experiment and theory leads to mutual enrichment.

The most recent investigations at the site of Sechín Bajo in the Casma valley resulted in the discovery of a sequence of three buildings dating from the Late Archaic to the Early Formative Periods, evidencing phases that span more than 2000 years (3500-1500 BC). The First Building comprised a simple platform that underwent numerous extensions, each phase of which received a circular sunken plaza. It was subsequently backfilled and sealed with a clay floor before the Second Building was constructed above it, expressing a change, both in its function and the way it was used. The Third Building represents the most monumental phase, demonstrating a pronounced division between a public area and another zone to which access was unmistakably restricted. In its public areas, the building’s surface was extensively decorated with clay reliefs, exhibiting a complex iconography. The abandonment of the structure, between 1500 and 1300 BP, involved either the destruction or walling-up of the flights of steps that granted access to it. On an external wall of the Second Building, c. 130 graffiti were inscribed. / Las investigaciones en el sitio arqueológico de Sechín Bajo, valle de Casma, han continuado y se ha registrado una secuencia de tres edificios correspondientes al Arcaico Tardío y Formativo Temprano, lo que representa una historia constructiva de 2000 años (3500 a 1500 a.C.). El Primer Edificio, el más antiguo, está compuesto por una plataforma rectangular que sufrió varias ampliaciones, siempre asociadas a plazas circulares hundidas. El Primer Edificio fue enterrado y sellado para levantar encima el Segundo Edificio, que tiene dos grandes fases constructivas. Posteriormente, se erigió el Tercer Edificio, que corresponde a una estructura de tamaño monumental, con cambios en los conceptos de uso y función, y modificaciones en su construcción. El Tercer Edificio tiene áreas de carácter público, con muros que presentan relieves relacionados con un corpus iconográfico bastante complejo, entre cuyos diseños sobresale el personaje denominado El Degollador, mientras que en los espacios privados los muros tienen hornacinas y los ingresos son restringidos. El decaimiento de Sechín Bajo, durante el Formativo Temprano, se puede reconocer en una pared exterior del Segundo Edificio —decorada con 130 grafitis realizados con una técnica muy simple—, en la destrucción de las escaleras principales y el sello de los accesos. Con estos nuevos datos, se pueden evaluar mejor las características de la arquitectura monumental-ceremonial en el valle de Casma desde el Arcaico Tardío al Formativo Temprano.

S100A12 porcina é um membro da família das proteínas S100, um grupo de pequenas proteínas ligantes de cálcio caracterizado pela presença de dois motivos “EF-hand”. Estas proteínas estão envolvidas em diversos eventos celulares, como a regulação da fosforilação protéica, atividade enzimática, tamponamento de Ca+2, processos inflamatórios e a polimerização de filamentos intermediários. Adicionalmente, algumas dessas proteínas podem ligar Zn+2, o qual pode afetar a ligação do íon Ca+2, particularmente para as proteínas S100. Neste trabalho, a seqüência gênica que codifica a proteína S100A12 porcina foi obtida por meio da construção de um gene sintético usando códons preferenciais para E.coli, permitindo a produção recombinante de grandes quantidades da proteína. Um estudo termodinâmico da estabilidade estrutural foi realizado, assim como a interação da proteína recombinante com íons divalentes usando técnicas de dicroísmo circular (CD) e fluorescência extrínseca. A desnaturação e renaturação induzidas por uréia ou temperatura indicam que se trata de um processo reversível e que a ligação dos íons Zn+2 e ou Ca+2 à rS100A12 aumenta sua estabilidade. A interação da sonda ANS com a proteína na presença de seus ligantes expõe superfícies hidrofóbicas podendo assim facilitar sua interação com macromoléculas alvo. Analisados em conjunto, os resultados obtidos indicam que S100A12 porcina é capaz de assumir diferentes conformações as quais podem estar correlacionadas com sua função fisiológica. / Porcine S100A12 is a member of S100 family, a small acidic calcium-binding proteins group characterized by the presence of two EF-hand motifs. These proteins are involved in many cellular events as the regulation of protein phosphorylation, enzymatic activity, Ca+2 homeostasis, inflammatory processes and intermediate filament polymerization. In addition, some of these proteins can bind Zn+2, which can affect the binding of Ca+2 particularly to S100 proteins. In this study, the gene sequence encoding S100A12 was obtained by the synthetic gene approach using E. coli codon bias allowing the recombinant production of large amounts of the protein. We report here a thermodynamic study on the structural stability of this recombinant protein and its interaction with divalent ions using circular dichroism and extrinsic fluorescence. The folding/unfolding induced by urea or temperature indicated a reversible process and the binding of Zn+2 or Zn+2 and Ca+2 to S100A12 increasing its stability. The interaction of the ANS probe with the protein in the ligant presence can lead to exposition of hydrofobic regions allowing its interaction with target macromolecules. Taken together, the results indicated that porcine S100A12 may assume different conformations that could be correlated to its physiological function.

As ligações de hidrogênio (LH), fundamentais na determinação da estrutura da água, proteínas, etc., são muito importantes no reconhecimento molecular e nos mecanismos de reações enzimáticas. A determinação da energia das LHs intramoleculares em proteínas e intermoleculares entre uma proteína e o solvente água, porque fornece informações sobre a estrutura secundária, terciária e quaternária das proteínas. Um método para quantificar e qualificar as LHs foi desenvolvido utilizando critérios de distância, geométricos e energéticos a partir das trajetórias obtidas por simulações de dinâmica molecular. O método foi testado com o monômero de uma fosfolipase A2 homodimérica, sem atividade catalítica, isolada do veneno da Bothrops asper(BaspMT-II). No dímero, a análise das LHs mostrou que elas são também essenciais na manutenção da estrutura quaternária. Essa análise permitiu identificar movimentos do tipo dobradiça acompanhados da formação transitória, na interface dimérica, de LHs controladas pelo triptofano na posição 77. Esses movimentos podem estar associados à ação danosa às membranas, uma vez que podem promover a inserção da região C-terminal na membrana. Estudos prévios mostraram que o peptídeo sintético (3Y codificado pelos aminoácidos 115-129 da BaspMT-II) apresenta atividade bactericida e citolítica. Um outro peptídeo (3W), mutante de 3Y, no qual três resíduos tirosina são substituidos por triptofano, apresenta um aumento do dano às membranas e do efeito miotóxico. Os mecanismos de ação desses peptídeos e as suas estruturas foram estudados por dinâmica molecular, dicroísmo circular (DC), microscopia de fluorescência e monocamadas de Langmuir (Mlang). As adsorções dos peptídeos em monocamadas de ácido dimiristoil fosfatídico (DMPA) e dimiristoilfosfatidilcolina (DMPC) se processam por mecanismos diferentes ocasionados pelas diferentes naturezas físico-químicas dos resíduos tirosina e triptofano. A microscopia de fluorescência acoplada a Mlang de DMPA com 3W adsorvido mostra um aumento da fluidez da monocamada, enquanto que o 3Y modifica os domínios do DMPA para pequenas estruturas circulares. Foram realizadas simulações dos peptídeos 3Y e 3W em meio aquoso e nas regiões interfaciais água/n-hexano e água/bicamadas de DMPC. Os resultados confirmam os obtidos por Mlang, demonstrando que os peptídeos interagem diferentemente com as membranas por adotar conformações alternativas definidas previamente. Essas conformações, diferentes das observadas em meio aquoso, dependem da natureza da interface. As estruturas encontradas no final das simulaçoes corroboram o mecanismo proposto por Mlang, assim como as estruturas sugeridas por DC. Isso sugere que a atividade biológica reduzida do peptídeo 3Y ocorre porque os seus dois resíduos Leu se adsorvem na interface sem penetrá-la. Ao contrário de 3W, os resíduos carregados do peptídeo 3Y não estão localizados corretamente para promover uma interação suficientemente atrativa para permitir a sua inserção na membrana celular. / Hydrogen bonds (HB) are highly important in the determination of the structure of the water and proteins. They also play a important role in molecular recognition and in enzyme reaction mechanisms. The determination of protein/water intermolecular and protein intramolecular HB energies provide information with respect to the formation and stabilization of secondary, tertiary and quaternary protein structure. A method that quantifies and qualifies the properties of HB was developed using distance, geometric and energy criteria as applied to data obtained from the atomic trajectories generated by molecular dynamics simulations. The method was tested with a monomer of a catalytically inactive homodimeric phospholipase A2 from Bothrops asper(BaspMT-II) venom. HBs at dimmer interface are essential for maintaining the quaternary structure, and are highly conserved during hinge-like movements of the dimmer. HB formed by tryptophan residue at position 77 controls this movement. These motions can be associated to the membrane damaging action since they facilitate the insertion of the C-terminus into the cellular membrane. Previous studies have shown that synthetic peptide (3Y, coding the amino acids 115-129 of BaspMT-II ) presents bactericidal and cytolitic activities. A peptide variant ( 3W ), in which tyrosine residues were substituted by tryptophan residues, presents an enhanced membrane damaging activity increased miotoxic effect. The mechanism of action of the peptides and their structures were studied by molecular dynamics simulations, circular dichroism (CD), fluorescence microscopy and Langmuir monolayers (Mlang). The adsorption of the peptides on a monolayer composed of dimiristoyl phosphatidic acid (DMPA) and dimiristoylphosphatidyl choline (DMPC) occurs through different processes due to the differences in the physic-chemical nature of the tyrosine and tryptophan residues. Fluorescence microscopy together with Mlang of DMPA with adsorbed 3W indicates an increase of the membrane fluidity while small circular domains are formed with DMPA. Simulations were conducted with the 3Y and 3W peptides in aqueous media, is a water/n-hexane and water/DMPC bilayers. The results confirm the Mlang results, showing that the peptides interact differently with the membranes by adopting alternative previously defined conformations. These two conformations, both of which are different to those observed in water, are dependent of the nature of the interfaces. The final simulated configurations confirm the mechanism proposed by Mlang and the structures proposed by CD. It is suggest that the reduced biological activity of the 3Y peptide is due to the two Leu residues that only adsorb to the cellular membrane without penetrating the bilayer. In contrast to the 3W peptide, no charged residue is correctly located to promote the interaction and insertion of the 3Y peptide into the membrane.

Muitas espécies do gênero Aristolochia (Familia Aristolochiaceae) têm sido usadas na medicina tradicional e folclórica como medicamentos e tônicos, as quais demonstravam atividades farmacológicas de interesse clínica e medica como anti-hemorrágica, anti-parasita, antibacteriano, antifúngico, analgésico, antitumoral entre outras. Visando a obtenção de mais informações sobre essas plantas e na procura por substâncias com efeitos antiofídicos, neste trabalho avaliou-se à ação de extratos aquoso, metanólico e de acetato de etila de folhas e caule contra as ações tóxicas da peçonha de Bothrops asper, ambos procedentes do Panamá e contra o efeito miotóxico da peçonha de Bothrops jararacussu e das miotoxinas BthTX-I (isolada de B. jararacussu) e Mtx-II (isolada de B. asper). O extrato das folhas em acetato de etila apresentou a melhor inibição da atividade fosfolipásica da peçonha de B. asper, demonstrando inibição de 45%, 35% e 33% nas proporções de 1:5, 1:10 e 1:30 (m/m), respectivamente. Enquanto que, o extrato de caule em acetato de etila demonstrou maior eficácia na neutralização da atividade coagulante, e, além disso, inibiu 96%, 92% e 87% do edema, da miotoxicidade e hemorragia induzidas pela peçonha de B. asper, respectivamente. Os percentuais diferenciados na neutralização das ações tóxicas da peçonha de Bothrops asper, revelam diferentes perfis do potencial antiofídico de Aristolochia sprucei. Um dos componentes bioativos foi isolado do extrato de caule desta planta por CLAE, e a caracterização química, por ressonância magnética nuclear, demonstrou ser o ácido aristolóquio que inibiu a atividade miotóxica das peçonhas de B. jararacussu e de B. asper em 80% e 85% e assim como a atividade miotóxica da BthTX-I e Mtx-II em 64% e 60%, respectivamente. A atividade hemolítica indireta da peçonha de B. asper foi inibida em 43% pelo o ácido aristolóquio. A análise dos espectros de dicroísmo circular e os estudos de interação por modelagem molecular sugerem que o ácido aristolóquio forma um complexo com a Mtx-II de B. asper inibindo sua atividade. A ligação do ácido aristoloquio com as miotoxinas (MjTX-1, BthTX-II) modificou a forma e a intensidade dos espectros de dicroísmo circular da miotoxina e induziu alterações na porcentagem dos diversos domínios que constituem a estrutura secundária desta miotoxina. Os resultados obtidos confirmam que os extratos de A. sprucei possuem propriedades antiofídicas e sugerem a necessidade de aprofundar estudos que permitam utilizar com segurança os extratos e o principio ativo isolado como suplementos dos antisoros para aumentar a eficácia na neutralização dos efeitos tóxicos locais da peçonha das serpentes. / A lot of species of genus Aristolochia (Familia Aristolochiacheae) have been used in traditional medicine and folk, such as medicaments and tonics, which show pharmacological activities of clinic and medical interest, like antihemorragic, antiparasitic, antibacterial, antifungic, analgesic, antitumoral between others. Expecting to get more information about these plants and in the search by substances with antiophidic effects, in this work was evaluated the action of aqueous, metanolic and ethyl acetate extracts from leaves and stems of Aristolochia sprucei against the toxic action of Bothrops asper venom, both native from Panamá and against the myotoxic effect of Bothrops jararacussu venom and BthTX1 (isolated from B. jararacussu) and Mtx-II (isolated from Bothorps asper). The leaves extracts in ethyl acetate showed the best inhibition registered of PLA2 activity of venom de B. asper showing inhibition of 45 %, 35 % and 33 %, in proportion (m/m) of 1:5, 1:10 and 1:30 respectively. As regards to stem extract in ethyl acetate, it showed high efficacy in neutralization of coagulant activity, besides It inhibited 96 %, 92 % and 87 % of edema, myotoxicity and hemorrhage induced by B. asper venom, respectively. One of bioactives components was isolated from stem extract of this plant by CLAE and the chemical characterization by nuclear magnetic resonance, this showed that the compound is the aristolochic acid. This compound inhibited the myotoxic activity of B. jararacussu and B. asper venom in 80 % and 85 %, so like myotoxic activity of BthTx-I and MTx-II in 64 % and 60 % respectively. The indirect hemolytic activity of B. asper venom was inhibited in 43 % by the aristolochic acid. The analyze of spectrum of circular dichroism and the studies of interaction by molecular modelagem suggest that the aristolochic acid forms a complex 1:1 with the miotoxin inhibiting their activity. The joint of aristolochic acid with the miotoxins (MjTX-1, BthTx-II) changes the way and the intensity of spectra from dichroism circular of miotoxin and It induced alteration in percentage of several domains that constitute a secondary structure from this toxin. The results obtained confirm that the extracts of A. sprucei have antiophidic properties and it suggest the necessity of deepen studies that allow to use with safety the extracts and the isolated active principle, like antiserum supplements to increase the efficacy in the neutralization of local toxics effects of snakes venoms.

As there are more than 1.4 billion smartphones sold every year in the world and around four million smartphones in Sweden. In recent years there has been a growing concern to move from a linear economic system to a circular economic system. Smartphones and other electronic equipment stand for the largest growing waste streams in the European Union. The rising prices of raw materials used in smartphone manufacturing over the last decades, along with the fact that these minerals are being mined in conflict stricken areas and the growing environmental awareness among people makes the refurbished smartphone’s market very current. Thus, it is of great interest to investigate consumer behaviour linked to refurbished smartphones as it is still in its early stages. As such, many of the barriers identified in this thesis can be linked to the communication of refurbished smartphones. The purpose of this thesis is to get a deeper understanding of how companies can communicate to break the barriers that exists for the consumer acceptance of refurbished smartphones in the Swedish market. Earlier studies have also focused on refurbishment as a concept rather than the consumer’s responses towards it. The study will be conducted in Sweden which has not been done previously. Therefore, our study will contribute to a deeper understanding of the consumer behaviour in the refurbished smartphone market in Sweden and thus aid companies in their communication of refurbished smartphones. To fulfil the purpose, a qualitative study has been conducted through semi-structured interviews. The sample groups were environmental enthusiasts, technology experts, refurbished product buyers, second hand buyers and companies. From the interviews five themes were derived: initial response, benefits, risks, barriers and communication. The findings and conclusions of the thesis are derived from the themes and subthemes that were created. There are many barriers and risks that make people avoid purchasing refurbished smartphones. The findings suggest that the consumers’ initial response are generally very positive and many consumers would consider a refurbished smartphone as their next smartphone purchase. Another finding is that a lack of knowledge about refurbishment lead to doubts about refurbished smartphones. The barriers found were lack of awareness, lack of thrill of newness, naming of refurbished products and lack of knowledge. The largest barrier, was lack of awareness. A solution to resolve this barrier could be to communicate the refurbishment process. A major finding was that that the environmental aspects were a vital purchase criteria for the consumers, however, not the most vital aspect. Moreover, societal benefits were raised regarding refurbished products in terms of benefitting the entire society. The biggest risk detected in the study was the performance, risk as the consumer may believe that the smartphone will be in a poor condition even though it has been refurbished. A big risk was the financial risk in terms of the substantial price for a refurbished smartphone. To reduce this the companies could adapt to the market standard and sell their refurbished smartphones in package deals. Our findings suggest that price should be communicated in combination with warranty and also environmental aspects, however, the environmental aspect is often abstract. The companies should consider using branding more to communicate these messages. Word of mouth was seen to be important and companies should utilise customer reviews more. In terms of emotional and rational appeals both should be used, however, what appeal that the companies should focus on emphasise on is not obvious.

Limit analysis is a very powerful tool to find accurate solutions of several geotechnical stability problems. This analysis is based on the theory of the plasticity and it provides two limiting solutions within lower and upper bounds. With the advancement of the finite elements and different robust optimization techniques, the numerical limit analysis approach in association with finite elements is becoming quite popular to assess the stability of various complicated structures. The present thesis deals with the formulations and the implementation of the finite element limit analysis to obtain the solutions of different geotechnical axisymmetric stability problems. The objectives of the present thesis are twofold: (a) developing limit analysis formulations in conjunction with linear and nonlinear optimizations for solving axisymmetric stability problems related with soil and rock mechanics, and then (b) implementing these axisymmetric formulations for solving various important axisymmetric stability problems in geomechanics. Three noded linear triangular elements have been used throughout the thesis. In order to solve the different problems, the associated computer programs have been written in MATLAB. With reference to the first objective of the thesis, the existing finite element lower bound axisymmetric formulation with linear programming has been presented. A new technique has also been proposed for solving an axisymmetric geomechanics stability problem by employing an upper bound limit analysis in combination with finite elements and linear programming. The method is based on the application of the von-Karman hypothesis to fix the constraints associated with the magnitude of the circumferential stress (), and finally the method involves only the nodal velocities as the basic unknown variables. The required computational effort becomes only marginally greater than that needed for an equivalent plane strain problem. The proposed methodology has been found to be computationally quite efficient. A new lower bound axisymmetric limit analysis formulation, by using two dimensional finite elements, the three dimensional Mohr-Coulomb (MC) yield criterion, and nonlinear optimization has also been presented for solving different axisymmetric stability problems in geomechanics. The nonlinear optimization was carried out by employing an interior point method based on the logarithmic barrier function. The yield surface was smoothened (i) by removing the tip singularity at the apex of the pyramid in the meridian plane, and (ii) by eliminating the stress discontinuities at the corners of the yield hexagon in the plane. No inherent assumption concerning with the hoop stress needs to be made in this formulation. The Drucker-Prager (DP) yield criterion was also used for computing the lower bound axisymmetric collapse load. The advantage of using the DP yield criterion is that it does not exhibit any singularity in the plane. A new proposal has also been given to simulate the DP yield cone with the MC hexagonal yield pyramid. The generalized Hoek-Brown (HB) yield criterion has also been used. This criterion has been smoothened both in the meridian and  planes and a new formulation is prescribed for obtaining the lower bound axisymmetric problems in rock media in combination with finite elements and nonlinear optimization. With reference to the second objective, a few important axisymmetric stability problems in soil mechanics associated with footings and excavations have been solved in the present thesis. In all these problems, except that of a flat circular footing lying over either homogeneous soil or rock media, it is assumed that the medium is governed by the MC failure criterion and it follows an associated flow rule. For determining the collapse loads for a circular footing over homogenous soil and rock media, the problem has been solved with the usage of Drucker-Prager, Mohr-Coulomb and Hoek-Brown criteria. The bearing capacity of a circular footing lying over fully cohesive strata, with an inclusion of a sand layer is evaluated. The effects of the thickness and internal friction angle of the sand layer () on the bearing capacity have been examined for different combinations of cu/(b) and q; where (i) cu defines the undrained shear strength, (ii)  is the unit weight of sand, (iii) b corresponds to the footing radius, and (iv) q is the surcharge pressure. The results have been presented in the form of a ratio () of the bearing capacities with an insertion of the sand layer to that for a footing lying directly over clayey strata. It is noted that an introduction of a layer of medium dense to dense sand over soft clay improves considerably the bearing capacity of the foundation. The improvement in the bearing capacity increases continuously (i) with decreases in cu/(b), and (ii) increases in  and q/(b). The bearing capacity factors, Nc, Nq and N, for a conical footing are obtained in a bound form for a wide range of the values of cone apex angle () and with  = 0, 0.5 and . The bearing capacity factors for a perfectly rough ( = conical footing generally increase with a decrease in . On contrary for  = 0, the factors Nc and Nq reduce gradually with a decrease in . For  = 0, the factor N for  ≥ 35o becomes minimum for  approximately equal to 90o. For  = 0, the factor N for  ≤ 30o, like in the case of  = , generally reduces with an increase in . It has also been intended to compute the bearing capacity factors Nc, Nq and N, for smooth and rough ring footing for different combinations of ri/ro and ; where ri and ro refer to inner and outer radii of the ring, respectively. It is observed that for a smooth footing, with a given value of ro, the magnitude of the collapse load decreases continuously with an increase in ri. On the other hand, for a rough base, for a given value of ro, hardly any reduction occurs in the magnitude of collapse load up to ri/ro ≈ 0.2, whereas beyond this ri/ro, the magnitude of the collapse load, similar to that of a smooth footing, decreases continuously with an increase in ri/ro. An attempt has also been made to determine the ultimate bearing capacity of a circular footing, placed over a soil mass which is reinforced with horizontal layers of circular reinforcement sheets. For performing the analysis, three different soil media have been separately considered, namely, (i) fully granular, (ii) cohesive frictional, and (iii) fully cohesive with an additional provision to account for an increase of cohesion with depth. The reinforcement sheets are assumed to be structurally strong to resist axial tension but without having any resistance to bending; such an approximation usually holds good for geogrid sheets. The shear failure between the reinforcement sheet and adjoining soil mass has been considered. The increase in the magnitudes of the bearing capacity factors (Nc and N) with an inclusion of the reinforcement has been computed in terms of the efficiency factors c and . The critical positions and corresponding optimum diameter of the reinforcement sheets, for achieving the maximum bearing capacity, have also been established. The increase in the bearing capacity with an employment of the reinforcement increases continuously with an increase in . The improvement in the bearing capacity becomes quite extensive for two layers of the reinforcements as compared to the single layer of the reinforcement. The stability of an unsupported vertical cylindrical excavation has been assessed. For the purpose of design, stability numbers (Sn) have been generated for both (i) cohesive frictional soils, and (ii) pure cohesive soils with an additional provision to account for linearly increasing cohesion with depth by using a non-dimensional factor m. The variation of Sn with H/b has been established for different values of m and ; where H and b refer to height and radius of the cylindrical excavation. A number of useful observations have been drawn about the variation of the stability number and nodal velocity patterns with changes in H/b,  and m. In the last, by using the smoothened generalized HB yield criterion, the ultimate bearing capacity of a circular footing placed over a rock mass is evaluated in a non-dimensional form for different values of GSI, mi, ci/(b) and q/ci. For validating the results, computations were exclusively performed for a strip footing as well. For the various problems selected in the present thesis, the failure and nodal velocity patterns have been examined. The results obtained from the analysis have been thoroughly compared with that reported from literature. It is expected that the various design charts presented here will be useful for the practicing engineers. The formulations given in the thesis can also be further used for solving various axisymmetric stability problems in geomechanics.

Orientadores: Narcizo Marques de Souza Neto, Flávio Cesar Guimarães Gandra / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-27T10:57:14Z (GMT). No. of bitstreams: 1 Veiga_LarissaSayuriIshibe_D.pdf: 10330689 bytes, checksum: 72bdd1a8fad1f82f880bb2c86fcd6a9e (MD5) Previous issue date: 2015 / Resumo: Este trabalho teve como objetivo a investigação de diversos mecanismos físicos provenientes das estruturas eletrônicas, magnéticas e cristalinas de sistemas ternários de terras raras e metais de transição 3d-5d através do uso das técnicas de espectroscopia de absorção de raios X e difração de raios X sob altas pressões. Dentre os fenômenos físicos estudados em função da compressão da rede cristalina induzida pela aplicação da pressão estão o magnetismo proveniente dos orbitais 4f e 5d nos sistemas ternários RERh4B4 (com RE = Dy e Er), os efeitos do campo elétrico cristalino e as interações de troca magnéticas nas perovskitas duplas 3d-5d (AFeOsO6, com A = Ca e Sr) e o acoplamento spin-órbita nos metais de transição 5d. As propriedades eletrônicas e magnéticas dos orbitais 4f e 5d das terras raras nos compostos da família RERh4B4 (RE = Dy e Er) foram investigadas através de experimentos de XANES e XMCD sob altas pressões na borda L3 do Dy e Er . Os sinais magnéticos das contribuições quadrupolar (2p3/2-> 4f) e dipolar (2p3/2->5d) presentes nos espectros de XMCD, em ambos os compostos, diminuem progressivamente em função da pressão. Este comportamento foi explicado em termos das interações de troca magnéticas entre os íons de terras raras, que são enfraquecidas pelas alterações locais da estrutura atômica induzidas pela compressão da rede cristalina. Já no sistema de perovskitas duplas, foi demonstrado que a compressão da estrutura Sr2FeOsO6, com um arranjo cristalino ordenado dos íons de Fe (3d) e Os (5d), permite o controle contínuo e reversível da coercividade e magnetização de saturação. Este efeito foi explicado em termos do aumento do campo elétrico cristalino em função da pressão, que altera as interações de troca magnéticas Fe-O-Os e transforma o material com magnetização remanente e coercividade praticamente nulas a pressão ambiente em outro com uma coercividade robusta (~0.5 T) e magnetização de saturação expressiva a pressões acima de ~10 GPa. Por fim, a última parte desta tese de doutorado foi dedicada ao uso da seletividade química e orbital da técnica de XANES na investigação do acoplamento spin-órbita nos elementos Pt (Pt0, 5d9) e Hf (Hf0, 5d2) sob altas pressões. Ao contrário do observado para a Pt, o cálculo do branching ratio a partir dos espectros de absorção nas bordas L2,3 do Hf revelaram que o acoplamento spin-órbita aumenta monotonicamente em função da pressão aplicada. Esse comportamento foi relacionado às propriedades supercondutoras e estruturais presentes nesse elemento sob altas pressões / Abstract: The scientific goal of this work has been the investigation of several physical mechanisms derived from the electronic, magnetic and structural properties of ternary rare earth and transition metal systems by means of X-ray absorption spectroscopy and X-ray diffraction techniques in a diamond anvil cell. Among the physical properties studied as a function of lattice compression induced by applied pressure are the magnetism of the 4f and 5d orbitals in tetragonal rare earth rhodium borides RERh4B4 (with RE = Dy e Er), the crystal electric field effects and magnetic exchange interactions in 3d-5d double perovskite systems (A2FeOsO6, with A = Ca e Sr) and the spin-orbit coupling in 5d transition metals. The electronic and magnetic properties of the rare earth 4f and 5d orbitals in the RERh4B4 (RE = Dy e Er) systems were investigated through high pressure XANES and XMCD experiments at Dy and Er L3 edges. For both compounds, the magnetic signals of the quadrupole (2p3/2->4f) and dipole (2p3/2->5d) contributions to the XMCD spectra progressively decrease as a function of pressure. This behavior was explained in terms of the magnetic exchange interactions between the rare earth ions, which are weakened by changes in the local atomic structure induced by compression of the crystal lattice. In the double perovskite system, it has been shown that compression of Sr2FeOsO6 structure with an ordered crystalline arrangement of iron (3d) and osmium (5d) transition metal ions, allows for continuous and reversible control of magnetic coercivity and saturation magnetization. This effect was explained in terms of enhanced crystal electric fields under high pressure, which alter the Fe-O-Os magnetic exchange interactions and transform the material with an otherwise mute response to magnetic fields into one with a strong coercivity (~0.5 T) and substantial saturation magnetization at pressures above ~10 GPa. Finally, the last part of this thesis is dedicated to the use of chemical and orbital selectivity of XANES technique as a tool to investigate the spin-orbit coupling in Pt (Pt0, 5d9) and Hf (Hf0, 5d2) elements under high pressures. Unlike observed for Pt, the calculated branching ratio determined from the integrated intensities of the Hf L2,3 white lines shows that the spin-orbit coupling increases monotonically as a function of applied pressure. This behavior was related to the superconducting and structural properties displayed by this element at high pressures / Doutorado / Física / Doutora em Ciências

The construction sector accounts for about one fifth of Sweden's greenhouse gas emissions. It is also the sector that produces the second most waste in Sweden. Today there is an increased need for housing in Sweden, at the same time as the construction sector must reduce its greenhouse gas emissions. Usually when renovating a building, construction products are disposed despite having a remaining service of life. The purpose of this study is to investigate how the reuse of construction products can be increased in the construction sector. And to find out how companies in Växjö work with reusing construction products. The work was based on the project Kv. Stommen, the project was about a new preschool in Vikaholm, Växjö. In the project the buyer had requested that some construction products should be reused. The purpose of the study was addressed by using interview methodology and partaking in focus group discussion with Godahåll during their meeting. According to the results there are seven challenges that must be overcome before the reuse of construction products in the construction sector can increase. The representatives from the companies in Växjö, who were interviewed had a positive attitude towards reuse of construction products. One conclusion is that there is an interest in the construction sector to use reused construction products and that it will increase in the future. Another conclusion is that by using reused construction products, the construction sector´s waste volumes can be reduced and contribute to a circular construction.