Suchergebnisse

The combustion of wood pellets in a fixed bed combustor of a 20 kW capacity domestic pellet boiler was tested according to several factors including Power, Excess Air (EA), Primary/Secondary air Split Ratio (SR) and Grate Area (GA). The Taguchi method was applied to program the experimental design. Several parameters were measured, including gas emissions (CO), fuel bed temperature (measured at 4 different heights), and efficiency. The experimental results show that the lower CO emission and the higher efficiency were obtained at medium thermal loads and the highest temperature on the fuel bed was obtained at about ¼ of its height (15 mm). The results obtained from the analysis of variance (ANOVA) show that the SR and the Power are the most important factors contributing to the CO reduction and also increase the fuel bed temperature. ; This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units, MEtRICs Project Scope: UIDB/04077/2020; Lelis Fraga was supported through a PhD Grant by Fundo de Desenvolvimento Capital Humano of the Government of Timor ...

It is common knowledge that internal combustion engines have the function of transforming thermal energy into useful mechanical work. During the combustion process of the fuel and air mixture (heat generation) a quantity of gases are produced and released into the environment by the exhaust system of these engines. When these machines were invented, their creators might not have had the notion that the generated gases would be aggressors to nature. The constant population growth, the increasing demand for the use of these engines and observations of the impact in nature, among them the health and greenhouse effects, evidenced mainly from the end of the last century, led scientists to study the problem related to gaseous emissions from these machines. The present work aims to study and evaluate the emissions of internal combustion engines, their consequences both to the human health and to the environment, the evolution of government legislation and also the control mechanisms implemented to reduce these pollutants. The applied methodology is a qualitative and exploratory study of bibliographic character of theoretical and experimental works that were presented in master's dissertations, doctoral theses, scientific articles and websites of companies specialized in the ...

Abstract. The present study examined whether personality traits and drinking motives interact to predict binge drinking and alcohol-related problems in a cross-cultural sample of college students. Participants were undergraduate drinkers ( N = 904; 66% female) from universities in Portugal ( N = 391) and the US ( N = 513). Participants completed measures assessing neuroticism, extraversion, conscientiousness, drinking motives, frequency of binge drinking, and the number of alcohol-related problems. A significant Country × Neuroticism × Conformity interaction was explained by differences between US and Portuguese samples. The effect of this interaction on alcohol- related problems was mediated by binge drinking. Findings suggest similarities and differences across cultures in the manner in which personality and drinking motives are associated with alcohol outcomes. Across cultures, neuroticism, extraversion, conscientiousness, and drinking motives are key factors to consider in the assessment, prevention, and treatment of alcohol use among college students.

Introdução: A pandemia de Covid-19 tem exigido adaptações e planejamentos constantes das instituições de ensino para a manutenção das atividades acadêmicas. Houve a substituição das disciplinas presenciais por remotas, através das Tecnologias de Informação e Comunicação (TICs). Como as atividades de cunho prático (como estágios acadêmicos) são fundamentais para os estudantes da Saúde, elas também migraram para a forma remota. Diante disso, modelos assíncronos de fornecimento de serviço foram sugeridos e regulamentados nesse período pandêmico. Objetivo: Relatar a experiência de estagiários do curso de Fonoaudiologia da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo na aplicação de atividades remotas direcionadas a escolares e idosos usuários de serviços de Atenção Primária à Saúde, durante a pandemia. Métodos: Trata-se de um estudo descritivo, do tipo relato de experiência. Resultados: Foram elaboradas ações passíveis de realização no ambiente domiciliar, segmentadas em atividades físicas, de linguagem e de memória, todas com abordagem lúdica, fornecendo oportunidades de interação e estimulação/aprimoramento dessas habilidades. Para os estudantes, as experiências foram fundamentais para o desenvolvimento dessa nova metodologia, estimulando sua criatividade. Conclusão: As atividades remotas dirigidas às crianças e idosos permitiram que essas populações fossem amparadas durante a restrição social. O estabelecimento de contato com o público-alvo e a possibilidade de interação com a comunidade foi muito importante para os estudantes. É possível a replicação das ações propostas a qualquer grupo, desde que sejam adequadas à faixa etária.

According to IPCC reports, global climate change is likely to be accompanied by a greater frequency, intensity, and duration of heat waves in urban areas. This is related to predicted and ongoing variation of atmospheric temperature and its association with the dynamical evolution of cities. Changes in the roughness pattern of the surface, wind intensity, soil available humidity and radiative properties compared to the natural surfaces characterize the formation of the Urban Heat Island (UHI). A dynamical downscaling of A2 and B1 SRES's future scenarios from Intergovernmental Panel on Climate Change were performed for Londrina, a medium-size city of Southern Brazil, using the Weather Research and Forecasting model. The main objective of this study is to investigate the impact of these scenarios on the UHI formation and intensity based on different input data, and its role and influence in the rural area. For this, an evaluation of the model and a comparison with the scenarios were done to mitigate the current trends. The results show a tendency in the current situation in following the pessimistic A2 scenario. Also, a drier rural area for the sustainable projection (B1) is found which implicates in a higher temperature and wind patterns modification for both sites, urban and rural region. Both future projections have a direct influence on the UHI intensity and formation, yielding effects in the agriculture and affecting conditions on human comfort over the region.