Physical-chemical and thermodynamic analyses of steam reforming of ethanol to hydrogen production

The steam reforming is one of most utilized process of hydrogen production because of its high production efficiencies and its technological maturity. The use of ethanol for this purpose is a interesting option because this is a renewable and less environmentally offensive fuel. The objective of this study is evaluate the physical-chemical, thermodynamic and environmental analyses of steam reforming of ethanol. whose objective is to produce 0.7 Nm3/h of hydrogen to be used by a PEMFC of l kW. In this physical-chemical analysis, a global reaction of ethanol was considered. That is, the superheated ethanol and steam, at high temperatures, react to produce hydrogen and carbon dioxide. Beyond it's the simplest form to study the steam reforming of ethanol to hydrogen production, it's the case where occurs the highest production of hydrogen (the product to be used by fuel cells) and carbon dioxide, to be eliminated. But this reaction isn't real and depends greatly on the thermodynamic conditions of reforming, technical features of reformer system and catalysts. Other products generally formed (but not investigated in this study) are methane, carbon monoxide, among others. It was observed that the products is commonly produced in the moment when the reaction attains temperatures about 206°C (below this temperature, the reaction trend to the reaetants, that is, from hydrogen and carbon dioxide to steam and ethanol) and the advance degree of this reaction increases when the temperature of reaction also increases and when its pressure decreases. It's suggested reactions at about 600°C or higher. However, when the temperature attains 700°C, the stability of this reaction is occurred, that is, the production of reaction productions attains to the limit, that is the highest possible production. In temperatures above 700°C, the use of energy is very high for produce more products, having higher costs of production that the suggested temperature. The indicated pressure is 1 atm., a value that allows a desirable economy of energy that would also be used for pressurization or depressurization of steam reformer. In exergetic analysis, it's seem that the lower irreversibililies occur when the pressure of reactions are lower. However, the temperature changes don't affect significantly the irreversibilites. Utilizing the obtained results from this analysis, it was concluded that the best thermodynamic conditions for steam reforming of ethanol is the same conditions suggested in the physical-chemical analysis. The exergetic and first law efficiencies are high on the thermodynamie conditions studied.

Independent and Combined Effects of Physical Activity and Sedentary Behavior on Blood Pressure in Adolescents: Gender Differences in Two Cross-Sectional Studies

Objectives: To examine the independent and combined association of physical activity (PA) and sedentary behavior (SB) on both systolic (SBP) and diastolic blood pressure (DBP) in adolescents from two observational studies. Methods: Participants from two cross-sectional studies, one conducted in Europe (n = 3,308; HELENA study) and the other in Brazil (n = 991; BRACAH study), were selected by complex sampling. Systolic and diastolic blood pressure (outcomes), PA and SB, both independently and combined, and potential confounders were analyzed. Associations were examined by multilevel linear regression. Results: Performing the recommended amount of PA (≥60 min/d) attenuated the effect of SB on DBP in BRACAH study girls and in boys from both studies. In contrast, PA did not attenuate the effects of SB on the SBP of girls in the HELENA study. The combination of less than recommended levels of PA with 2-4 h/d of sedentary behavior was found to be associated with increased SBP in boys from both studies. Conclusions: Meeting current PA recommendations could mediate the association between SB and DBP in both sexes. In boys, the joint effect of low levels of PA and excessive sedentary activity increases SBP levels. Longitudinal studies are required to confirm these findings. © 2013 de Moraes et al.

Os significados e as implicações da extensão universitária na formação inicial e na atuação profissional em educação física

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inclusão escolar: um estudo da formação continuada dos professores de educação física na cidade de Araraquara - SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Padrão cinemático do chute no futebol: comparação entre endivíduos praticantes e não praticantes, nas situações de descanso e exaustidão

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A disciplina de ginástica artística na formação do licenciado em educação física sob a perspectiva de docentes universitários

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A pedagogia do professor de educação física: um estudo sobre valores e as atitudes na prática docente

Pós-graduação em Ciências da Motricidade - IBRC

Campos de luta: o processo de construção coletiva de um livro didático na educação física no ensino médio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A formação profissional em educação física no Pará e a aspiração discente

Este artigo tem como objetivo buscar reconhecer a identidade do profissional de Educação Física que está sendo construída e se os Cursos Superiores de Educação Física no Pará vão ao encontro da aspiração dos discentes desses cursos. Foram analisados os Projetos Político-Pedagógicos da Universidade do Estado do Pará (UEPA) e da Universidade Federal Pará (UFPA – campus Belém e campus Castanhal) e entrevistados os alunos do último semestre desses cursos, usando-se como técnica de análise, a Técnica de Elaboração e Análise de Significado (MOREIRA; SIMÕES, PORTO, 2005) para serem identificadas as aspirações dos discentes. Pode-se concluir, com esse estudo, que os Projetos Político-Pedagógicos dos Cursos de Educação alunos entrevistados, o curso não atende às suas expectativas quanto à sua formação processo de formação seja revisto.

Os jogos digitais como apoio pedagógico nas aulas de educação física escolar pautadas no currículo do Estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Jogos digitais educacionais nas aulas de Educação Física: Olympia, um videogame sobre os jogos olímpicos

Pós-graduação em Desenvolvimento Humano e Tecnologias - IBRC

Os conteúdos e a prática pedagógica dos professores de educação física: análise do currículo do estado de São Paulo

Pós-graduação em Desenvolvimento Humano e Tecnologias - IBRC