Aplicação da destilação simulada por cromatografia gasosa e da termogravimetria para a avaliação da influência da redução do teor de enxofre sobre as propriedades físico-químicas do óleo diesel

One of the main problems related to the use of diesel as fuel is the presence of sulfur (S) which causes environmental pollution and corrosion of engines. In order to minimize the consequences of the release of this pollutant, Brazilian law established maximum sulfur content that diesel fuel may have. To meet these requirements, diesel with a maximum sulfur concentration equal to 10 mg/kg (S10) has been widely marketed in the country. However, the reduction of sulfur can lead to changes in the physicochemical properties of the fuel, which are essential for the performance of road vehicles. This work aims to identify the main changes in the physicochemical properties of diesel fuel and how they are related to reduction of sulfur content. Samples of diesel types S10, S500 and S1800 were tested according with the methods of the American Society for Testing and Materials (ASTM). The fuels were also characterized by thermogravimetric analysis (TG) and subjected to physical distillation (ASTM D86) and simulated distillation gas chromatography (ASTM D2887). The results showed that the reduction of sulfur turned the fuel lighter and fluid, allowing a greater applicability to low temperature environments and safer for transportation and storage. Through the simulated distillation data was observed that decreasing sulfur content resulted in higher initial boiling point temperatures and the decreasing of the boiling temperature of the medium and heavy fractions. Thermogravimetric analysis showed a loss event mass attributed to volatilization or distillation of light and medium hydrocarbons. Based on these data, the kinetic behavior of the samples was investigated and it was observed that the activation energies (Ea) did not show significant changes throughout conversion. Considering the average of these energies, the S1800 had the highest Ea during the conversion and the S10 the lowest values

Desempenho físico em idosos com diferenciados perfis epidemiológicos: análise do estudo IMIAS International Mobility in Aging Study sob a perspectiva do curso da vida e de biomarcadores da inflamação e do estresse

O crescimento demográfico de idosos é um fenômeno mundial e exerce influência sobre o desenvolvimento e funcionamento das sociedades. Fatores sociais, econômicos, ambientais, biológicos e culturais influenciam o processo de envelhecimento, que pode vir acompanhado de contínua perda na capacidade de adaptação do indivíduo ao meio ambiente, de maior vulnerabilidade ao estresse, limitações funcionais e diminuição da qualidade de vida do indivíduo. Todavia, ao longo do curso da vida, o indivíduo vivencia múltiplas exposições adversas à saúde, e o declínio da mobilidade surge como um dos primeiros sinais do envelhecimento, repercutindo na saúde física e mental do indivíduo. Para contribuir com o conhecimento sobre os desfechos relacionados ao envelhecimento e mobilidade, o estudo IMIAS investiga idosos em quatro países com diferentes perfis epidemiológicos. O presente estudo abordou os possíveis fatores associados ao declínio físico em idosos de distintas sociedades, sobre a perspectiva epidemiológica do curso da vida e dos biomarcadores da inflamação e do estresse. Objetivos: 1) Analisar as relações entre as adversidades sociais e econômicas, vivenciadas durante a infância, a fase adulta e a velhice, com o baixo desempenho físico em populações idosas, de diferentes contextos sociais, econômicos e culturais. 2) Verificar a associação entre os níveis elevados da proteína c-reativa (PCR) com o desempenho físico em idosos de diferentes populações. 3) Avaliar se a desregulação nos níveis de cortisol diurno exerce influência sobre o desempenho físico em idosos com distintos perfis epidemiológicos. Métodos: Foram utilizados dados da linha de base do IMIAS – Estudo Internacional de Mobilidade no Envelhecimento, composto por 1.995 indivíduos entre 65 e 74 anos de idade, residentes em comunidades de quatro países (Albânia, Brasil, Canadá, Colômbia). O desempenho físico foi avaliado através do Short Physical Performance Battery (SPPB) e da força de preensão manual. As adversidades durante o curso da vida foram estimadas a partir de eventos e exposições sociais, econômicas e culturais ocorridas durante a infância, fase adulta e velhice. Para avaliar o percurso biológico e suas associações com a mobilidade, a proteína c-reativa e o cortisol foram considerados como biomarcadores da inflamação e do estresse, respectivamente. No sentido de responder as questões de investigações, foram conduzidas análises de estatística descritiva, bivariada e multivariada, mediante técnicas de distribuição de frequências, teste qui-quadrado, odds ratio e regressões logística, linear e multinível. Resultados: O desempenho físico foi menor nos participantes que vivem na Colômbia, Brasil e Albânia do que nos que vivem no Canadá, mesmo quando ajustados por idade, sexo e adversidades durante o curso da vida. O baixo nível de desempenho físico (SPPB < 8) foi associado a ter sofrido adversidade social e econômica na infância, ter tido ocupação semiqualificada na fase adulta, morar sozinho e possuir renda insuficiente na velhice. A PCR esteve associada com a baixa força de preensão manual e com o SPPB<8. Entretanto, a associação entre a PCR e a força de preensão manual não se manteve quando ajustada por fatores socioeconômicos e hábitos de saúde. As associações negativas entre SPPB e PCR permaneceram significativas mesmo após ajustes por idade, sexo, escolaridade, local de pesquisa e condições de saúde. O baixo desempenho físico (SPPB ≤ 8) foi associado com uma significativa diminuição nos níveis de cortisol ao acordar, em comparação com os níveis de cortisol de idosos com bom desempenho físico (SPPB > 8), mesmo após modelos controlados por local de estudo, sexo, depressão, hábitos de saúde, uso de psicotrópicos e índice de massa corporal. Conclusões: Os resultados evidenciaram associação entre a inflamação, o estresse e as desigualdades sociais e econômicas na infância, sobre o desempenho físico de idosos com diferenciados perfis epidemiológicos. Enfatizamos que a promoção do envelhecimento saudável requer considerar políticas e práticas que favoreçam o bem-estar econômico e social para crianças, adultos e idosos.

Do modelo geométrico ao modelo físico: o tridimensional na educação do arquiteto e urbanista

In the teaching practice of architecture and urbanism in Brazil, educational legislation views modeling laboratories and workshops as an indispensable component of the infrastructure required for the good functioning of any architectural course of study. Although the development of information technology at the international level has created new possibilities for digital production of architectural models, research in this field being underway since the early 1990s, it is only from 2007 onwards that such technologies started to be incorporated into the teaching activity of architecture and urbanism in Brazil, through the pioneering experience at LAPAC/FEC/UNICAMP. It is therefore a recent experiment whose challenges can be highlighted through the following examples: (i) The implementation of digital prototyping laboratories in undergraduate courses of architecture and urbanism is still rare in Brazil; (ii) As a new developing field with few references and application to undergraduate programs, it is hard to define methodological procedures suitable for the pedagogical curricula already implemented or which have already been consolidated over the years; (iii) The new digital ways for producing tridimensional models are marked with specificities which make it difficult to fit them within the existing structures of model laboratories and workshops. Considering the above, the present thesis discusses the tridimensional model as a tool which may contribute to the development of students skills in perceiving, understanding and representing tridimensional space. Analysis is made of the relation between different forms of models and the teaching of architectural project, with emphasis on the design process. Starting from the conceptualization of the word model as it is used in architecture and urbanism, an attempt is made to identify types of tridimensional models used in the process of project conception, both through the traditional, manual way of model construction as well as through the digital ones. There is also an explanation on how new technologies for digital production of models through prototyping are being introduced in undergraduate academic programs of architecture and urbanism in Brazil, as well as a review of recent academic publications in this area. Based on the paradigm of reflective practice in teaching as designed by Schön (2000), the experiment applied in the research was undertaken in the integrated workshop courses of architectural project in the undergraduate program of architecture and urbanism at Universidade Federal do Rio Grande do Norte. Along the experiment, physical modeling, geometric modeling and digital prototyping are used in distinct moments of the design process with the purpose of observing the suitability of each model to the project s phases. The procedures used in the experiments are very close to the Action Research methodology in which the main purpose is the production of theoretical knowledge by improving the practice. The process was repeated during three consecutive semesters and reflection on the results which were achieved in each cycle helped enhancing the next one. As a result, a methodological procedure is proposed which consists of the definition of the Tridimensional Model as the integrating element for the contents studied in a specific academic period or semester. The teaching of Architectural Project as it is developed along the fifth academic period of the Architecture and Urbanism undergraduate program of UFRN is taken as a reference

Análise por meio de espectroscopia de emissão óptica das espécies ativas em nitretação iônica e gaiola catódica

Plasma process like ionic nitriding and cathodic cage plasma nitriding are utilized in order to become hard surface of steels. The ionic nitriding is already accepted in the industry while cathodic cage plasma nitriding process is in industrial implementation stage. Those process depend of plasma parameters like electronic and ionic temperature (Te, Ti), species density (ne, ni) and of distribution function of these species. In the present work, the plasma used to those two processes has been observed through Optical Emission Spectroscopy OES technique in order to identify presents species in the treatment ambient and relatively quantify them. So plasma of typical mixtures like N2 H2 has been monitored through in order to study evolution of those species during the process. Moreover, it has been realized a systematic study about leaks, also thought OES, that accomplish the evolution of contaminant species arising because there is flux of atmosphere to inside nitriding chamber and in what conditions the species are sufficiently reduced. Finally, to describe the physic mechanism that acts on both coating techniques ionic nitriding and cathodic cage plasma nitriding

Tratamento térmico do titânio e suas consequências sobre as propriedades físico-químicas e de biocompatibilidade

The titanium and titanium alloys are widely used as biomaterial in biomedical device and so research have been developed aiming to improve and/or better to understand interaction biomaterial/biological environment. The process for manufacturing of this titanium implants usually involves a series of thermal and mechanical processes which have consequence on the final product. The heat treatments are usually used to obtain different properties for each application. In order to understand the influence of these treatments on the biological response of the surface, it was done, in this work, different heat treatments in titanium and analyzed their influence on the morphology, adhesion and proliferation of the pre-osteoblastic cells (MC3T3-E1). For such heat-treated titanium disks were characterized by optical microscopy, contact angle, surface energy, roughness, microhardness, X-ray diffraction and scanning through the techniques (BSE, EDS and EBSD). For the analysis of biological response were tested by MTT proliferation, adhesion by crystal violet and β1 integrin expression by flow cytometry. It was found that the presence of a microstructure very orderly, defined by a chemical attack, cells tend to stretch in the same direction of orientation of the material microstructure. When this order does not happen, the most important factor influencing cell proliferation is the residual stress, indicated by the hardness of the material. This way the disks with the highest level state of residual stress also showed increased cell proliferation

Efeito da adição de fibras da palma do licuri (syagrus coronata) no comportamento físico e mecânico de compósitos de matriz cimentícia

This research was motivated by the requirement of asbestos s replacement in building systems and the need to generate jobs and income in the country side of the state of Bahia, Brazil. The project aimed at using fibers from licuri leaves (syagrus coronata), an abundant palm in the region, to produce composites appropriate for the sustainable production of cement fibre reinforced products in small plants. The composites were produced in laboratory using Portland cement CP-II-F32, sand, water, licuri palm fiber contents of 1.0, 1.5 and 2.0% by weight of binder (two different fiber length) and metakaolin. The latter was chosen as an additional binder for its efficiency to reduce the alkalinity of cementitious matrixes therefore preventing the degradation of vegetable fibers. The characterization of the composite components was carried out by sieving and laser particle size analyses, thermal analysis, fluorescence and X-ray diffraction. The composites performance was evaluated by 3- point-bending tests, compressive strength, ultrasound module of elasticity, free and restrained shrinkage, water capillarity absorption and apparent specific gravity. It has been found that the addition of fibers increased the time to onset of cracking over 200.00% and a 25% reduction in cracks opening in the restrained shrinkage test. The capillary absorption reduced about 25% when compared to fiber-free composites. It was also observed with regard to flexural strength, compressive strength and specific gravity, that the addiction of fibers did not affect the composite performance presenting similar results for compounds with and without fibers. In general it can be stated that the reinforced composite fibers of palm licuri presents physical and mechanical characteristics which enable them to be used in the intended proposals of this research