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A importância da caracterização do módulo de elasticidade e do amortecimento de refratários por técnica dinâmica
(Universidade Federal de São Carlos, 2013-03-08) Exposito, Caio Cesar Dente; Rodrigues, José de Anchieta; https://lattes.cnpq.br/4000441989868775; https://lattes.cnpq.br/7830288943074148
This dissertation tries to understand the mechanisms involving damping phenomenon in ceramic refractory materials, using a dynamic technique. Damping proves to be an interesting parameter to analyze thermal shock damage in these sorts of materials. This technique would make possible to compare damping measurements with well-established techniques, such as the determination of modulus of elasticity modulus and modulus of rupture. Furthermore, this study attempts to understand the nonlinear phenomenon in damping and modulus of elasticity that depends on the vibrational amplitude. Aiming to understand how the variation on the vibration amplitude affects the mzasured values of damping and modulus of elasticity and how the nonlinear effect can be used in our advantage and in industrial daily routine, such as determining whether samples are damaged or not without a previous analysis or a standard material for reference. This study also approaches the influence of water in the nonlinear behavior of damping and modulus of elasticity. Thus, it would be possible to establish trustable and standardize procedures to measure those. In addition it would be possible to understand the drying process of ceramic refractory castables.
Efeito Aharonov-Bohm sem interação com a fronteira do solenóide
(Universidade Federal de São Carlos, 2013-03-08) Romano, Renan Gambale; Oliveira, César Rogério de; https://lattes.cnpq.br/5485204156806697; https://lattes.cnpq.br/2317413965575635
One of the biggest problem in the mathematical modeling of the Aharonov- Bohm Effect is the interaction between the electron and the solenoid border. Such interaction translates into boundary conditions on that border, which causes great ambiguity because in principle it is not clear what the most appropriate choice. In quantum mechanics this conditions represent self-adjoint extensions of the Schrödinger operator of the problem. On the other hand, recent works has demostrated that it is possible to confine quantum particles in certain regions of Rn with magnetic fields sufficientily intense near the border of that region. Mathematically this corresponds to essentially selfadjoint Schrödinger operators, which means exemption from the particle interation with the solenoid border In this work we intend to combine the two situations mentions above to study the Aharonov-Bohm effect in the plane, adding then external magnetic fields and potentials that are suffiently intense in the solenoid border so that the related Schrödinger operator is essentially self-adjoint.
Óxidos mistos de magnésio e alumínio contendo lítio e cálcio como catalisadores para transesterificação etílica
(Universidade Federal de São Carlos, 2013-03-08) Castro, Cínthia Soares de; Assaf, José Mansur; https://lattes.cnpq.br/9563312407691130
This work deals with the investigation on the production of heterogeneous catalysts of base surface properties applied for ethylic transestérification, aiming the biodiesel production. In the first and second chapters of this thesis, oxide catalysts containing Li were prepared from incipient wet impregnation method on different supports [SÍO2, MgO, Y-AI2O3 and Mg(Al)0 obtained from MgAl hydrotalcite], using optimized calcination conditions. The materials were characterized by XRD, N2 Fisissorption, ICP-OES, SEM, XPS and TPD of C02. The Li+ addition to the catalysts caused morphologic changes, surface area reduction and increased the oxides crystallite size. On the other hand, Li+ caused a steep increase in the oxide reactivities due to the increase in the base sites strength. These materials were evaluated as catalysts in the model transestérification reaction between methyl acetate and ethanol, under mild reaction conditions. The higher the lithium content in the Li/Mg(Al)0 catalysts, the higher the activity and the different studied supports deeply affected their performances for transestérification. The lithium reaction with the supports Y-AI2O3 and SÍO2 led to lithium aluminates and silicates, inactive for reaction. However, Li/MgO and Li/Mg(Al)0 showed to be very active, mainly due to the presence of large amounts of strong base sites (low coordination O2' anions). Li/Mg(Al)0 exhibited conversion even higher than that obtained for Li/MgO. Nevertheless, Li+ leaching was detected in the solution, which resulted in some homogeneous reaction. Indeed, the stability of the Li+ containing catalysts must be improved in order to be able to be used in the biodiesel production. In the third chapter of this thesis, Ca based oxides, namely Ca/MgAl, were synthesized by impregnation of different contents of Ca nitrate onto MgAl hidrotalcita, and followed by calcination. These materials were characterized by XRD, N2 Fisissorption, SEM-EDS and TPD of CO2 revealing that they are mainly comprised of a oxides mixture [CaO + Mg(Al)0] and that the surface CaO is partially hydrated and carbonated. These materials were also evaluated as catalysts in the model transestérification reaction between methyl acetate and ethanol. By increasing the Ca content on the catalysts, the activity is enhanced, probably because of the formation of a highly basic CaO, well dispersed over the support matrix. The Ca/Mg(Al)0 catalysts can be reused for at least 5 batch runs, with low Ca2+ leaching to the solution. Therefore, the Ca/Mg(Al)0 revealed to be promising candidates as heterogeneous catalysts for ethylic biodiesel production.
Escala metacognitiva para idosos: elaboração de itens e análise dos parâmetros psicométricos
(Universidade Federal de São Carlos, 2013-03-08) França, Alex Bacadini; Schelini, Patrícia Waltz; https://lattes.cnpq.br/6185333517392859; https://lattes.cnpq.br/9529429020135975
New studies and ways of intervening with the elderly population are emerging, given that we now know that aging not necessarily accompanied by cognitive decline. Along with studies on other aspects of aging, the metacognitive processes that coordinate cognitive performance, have begun to acquire importance in the literature over the past four decades. Metacognition represents thoughts and knowledge that individuals have about their own thoughts and cognitive processes. Two of its basic elements are: metacognitive knowledge, characterized by awareness of the processes and skills necessary to perform a given task, and control or cognitive self-regulation, which includes judgment about the effectiveness of the strategies being used and the establishment of new ones. Considering that metacognition facilitates the effective performance of activities and given the lack of Brazilian instruments to measure it, the main objective of the study is the development of a scale for the assessment of metacognition among the elderly and analysis of the validity and accuracy of this scale. The first stage of the study involved the development of the Metacognition Scale - Senior (EMETA-S), for each topic, the participant, must choose from four possible answers, the one that best characterizes him or her. The second stage aimed to investigate evidence of content validity. For this step, the instructions and the 74 original items of the instrument were sent to three experts. The index of agreement resulting from the analysis of the responses of the experts was 68%. The scale was also tested with a sample of 15 participants (60 aged years or over) in verify whether or not the instructions and the items were understandable, which resulted in some changes in the wording of the instructions and items, as well as in the descriptors of the scale, constituting the third stage of the study. A factor analysis performed on the data gathered with a sample of 194 participants revealed the presence of two factors: selfregulation and metacognitive knowledge, accounting for 27.18% of the variance in the responses. After exclusion of items that had factor loadings below 0.30, items misunderstood by participants and items that were highly similar to others items, the final version of the EMETA-S was composed of 27 items, with internal consistency of 0.85. No significant differences were found between the average performance with respect to variables such as gender, education and age of participants. The analysis of the validity and accuracy of the items indicated suitability of the concept initially proposed and good internal consistency of the scale.
Mecanismos comportamentais e moleculares envolvidos na interação entre as substâncias de abuso e os fatores de risco para o desenvolvimento da dependência
(Universidade Federal de São Carlos, 2013-03-08) Leão, Rodrigo Molini; Planeta, Cleopatra da Silva; https://lattes.cnpq.br/9991437191368026
Tobacco and ethanol are the most used drugs in the world and often co-abused. An important issue in the field of drug abuse research is the characterization of risk factors related to increased vulnerability to drug addiction. In the present study we investigated in rats: a) the effects of exposure to variable stress on nicotine-induced locomotor activation, CREB and ERK activities in the prefrontal cortex, nucleus accumbens and amygdala and nicotine intravenous self-administration; b) whether previous exposure to cocaine could affect nicotine seeking behaviors, and if this phenomenon could be related to alterations in the BDNF, TrkB, DYN, Mi-Opio, NPY and CRFR1 gene expression in the nucleus accumbens; c) whether repeated nicotine treatment could induce anxiety-like behavior, which in turn increases alcohol intake; d) the effect of simultaneous nicotine treatment during the transition to development of alcohol dependence and whether that is mediated by activation of neuronal ensembles in different parts of the brain. We found: the variable stress exposure caused cross sensitization with nicotine, increased the nicotine selfadministration behavior and decreased CREB activity in mesencephalic areas; the pretreatment with cocaine caused sensitization of cocaine motor response, locomotor cross-sensitization with nicotine, and increased motivation to nicotine intake; the pretreatment with nicotine increased the anxiety-like behavior and the motivation to ethanol intake; the simultaneous administration of nicotine and ethanol vapor exposure speed up the escalation of ethanol self-administration, increased the motivation and the compulsivity to ethanol intake and these behaviors could be related to activation of extended amygdala and mesocorticolimbic systems. Our results suggest that additional factors to the drug use such as stress and preexposure to other drug could increase the vulnerability to addiction.
A Filosofia Crítica de Bergson
(Universidade Federal de São Carlos, 2013-03-08) Mascarenhas, Aristeu Laurêncio Cordeiro; Marques, Silene Torres; https://lattes.cnpq.br/4822141288006918; https://lattes.cnpq.br/9758890809066139