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Propriedades estruturais e eletrônicas de nanopartículas de Cu modificam a estrutura superficial do cobre e influenciam na atividade catalítica para a reação deslocamento gás água
(Universidade Federal de São Carlos, 2017-08-16) Caldas, Paula Cristina de Paula; Bueno, José Maria Corrêa; https://lattes.cnpq.br/0157452280626031; https://lattes.cnpq.br/3466253594165485
The Cu catalysts activity is modified by reducible supports, such as cerium and praseodymium oxides. The interaction of these oxides with Cu nanoparticles prevent agglomeration and generate active interface sites. The relationship between structure and reaction velocity have been calculated from model catalysts that have properties very far from a real catalyst. One of the great challenges is the understanding of ceria and praseodymia effects on the modification of the properties of copper catalytic sites. The activity - structure relationship during the water gas reaction for supported copper catalysts in interaction with cerium or praseodymium oxides or not was investigated on this study. Through in situ studies, it was found that for the Cu/Al2O3 catalysts the growth of the metal particle, caused by the increase of the Cu content supported in the alumina, led to a decrease in the oxygen coating degree. Which, in turn, generated an increase on the surface electron density of the particle resulting in the elongation of the Cu-O surface bonding distance. When different ceria or praseodymia contents were added to the Cu/Al2O3 catalysts did not cause significant changes in particle size and the oxidation state of copper. However, the oxide-metal interaction resulted in an increase on the surface electron density of the copper particle causing an increase in the Cu-O bond distance over the non-promoted catalysts. A linear correlation between Cu-O binding distance and catalytic activity for WGSR is observed. Therefore, Cu-O bonding distance reflects the electronic properties and activity of copper sites.
Propriedades físicas de modelos integráveis
(Universidade Federal de São Carlos, 2017-08-16) Tavares, Thiago Silva; Ribeiro, Giuliano Augustus Pavan; https://lattes.cnpq.br/7955854896355856; https://lattes.cnpq.br/0662651860802736
In this thesis we tackled two di erent problems of quantum integrability. We derived nite sets of non-linear integral equations to describe physical properties of quantum chains invariant under the super-algebras su(2|1) and osp(1|2); and we also studied the in uence of boundary conditions on the bulk properties of the six-vertex model. The su(2|1) invariant model is a multi-chain generalization of the super-symmetric t-J model. Using the quantum transfer matrix method we obtained the phase diagram. For the osp(1|2) invariant model we could also rewrite the Hamiltonian in the language of itinerant fermions interacting through exchange, although the Hamiltonian itself is not hermitian, which corresponds to a non-unitary eld theory. We analytically computed the (e ective) central charge of this theory, corroborating numerical results of the literature. These results point towards the possibility of generalization of such non linear integral equations for models of di erent symmetries. Concerning the problem of the in uence of boundary conditions on the six-vertex model, we showed the existence of in nitely many boundaries whose intensive properties disagree with the standard periodic boundary condition SPBC = 32 ln(43). We also proved that by a suitable choice of boundary conditionsany entropy value in the interval [0, 12 ln(3324)] is accessible. We conjectured that the sameis true for the interval [ 1 2 ln(3324), SPBC]. The number of configurations of the six-vertex model with fixed boundary condition amounts to the enumeration problem of generalized alternating sign matrices.
A financeirização do varejo nacional: um estudo multicasos do segmento de vestuário, calçados e acessórios
(Universidade Federal de São Carlos, 2017-08-16) Costa, Eliane Aparecida; Saltorato, Patrícia; https://lattes.cnpq.br/4086015205835355; https://lattes.cnpq.br/4246880831905518
This paper aims to explore the advance of the diffusion of the financial logic on the national clothing retail in the promotion of consumer credit in Brazil. In this sense, it looks to verify how this advance is configured in a new organizational arrangement that is signed by the formation of partnerships between the financial institutions and the retail companies, as well as to analyze the administrative strategy to manage this new model, in view of its Social and labor implications. We analyzed eight companies in the national retail clothing sector that have a strong expression in consumption in Brazil, from 2008 to 2016. The companies of this sampling are Marisa, Renner, Riachuelo, Pernambucanas, Cia. Hering, Arezzo & Co, Restoque Commerce and Garment Apparel and Grazziotin Group, which previously had the commercial object of trading merchandise and today deal with consolidated variables in the financial Market. In this work, it is analyzed how the mergers and acquisitions movements involving financial institutions and retail companies are shaping the domestic market, and also how organizational models are managed after the adoption of partnerships with financial institutions and which Impacts of the expansion of this model on labor relations. The results obtained point to a better understanding of the need to adapt to the process, which requires a gradual change in the current organizational structure and consequent prevention of damages related to labor issues, values added to shareholders or positions of CEOs, obliged to increase a series of variables that result in change in the segment. These factors exemplify the materialization of financialization strategies among the largest national apparel retailers, and also show how the banking process is affecting the profile of the commercial model of the national retail sector.