Browsing by Issue Date, starting with "2019-05-21"
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- Externalidades associadas ao transporte aéreoPublication . Nascimento, Leroy Arias Boa Morte do; Silva, Jorge Miguel dos ReisO transporte aéreo é um sector de atividade com externalidades positivas e negativas, sendo a positiva, todas as receitas diretas e indiretas associadas ao transporte aéreo, e por outro lado a negativa, são os gases de efeito de estufa e de ruído, com custos de impactos na saúde publica, agricultura, biodiversidade entres outros recursos naturais, constituindo uma grande preocupação para as entidades internacionais que regulam este sector de atividade tendo em conta a influência deste efeito no nosso quotidiano. A ICAO vem implementando regulamentos na contenção dessas externalidades, como inovação tecnológica, na melhoria de consumo de combustível e eficiência energética, juntamente com as empresas fabricantes. Este trabalho realça os resultados de aproximação de externalidades (Ruídos e GEE) associadas ao transporte aéreo em São Tomé e Príncipe no ciclo LTO padronizada pela ICAO na política de mitigação de poluentes dos motores das aeronaves, que têm como consequência a proliferação do Gás de efeito de Estufa que tem degradado o meio ambiente e a saúde publica. Este trabalho teve como base os dados estatísticos dos anos 2016 e 2017 do INAC, onde foram analisados os movimentos, rotas, tráfego e as frotas das aeronaves das operadoras que operam no aeroporto internacional de São Tomé e Príncipe de voo regular, por meio de análises dos motores das aeronaves através do certificado tipo de cada uma das aeronaves e pela base de dados de emissões de escapes da ICAO e da EASA de acordo com o processo operacional de redução de ruídos. No que diz respeito às taxas de ruídos, os valores diferem entre os aeroportos mundiais, muitas vezes dependem da localização e do fluxo do tráfego aéreo, e a política de cobrança das taxas de ruído nos aeroportos mundiais tem como objetivo que as companhias aéreas reajustem o tipo de rota e aeronaves a operarem e por outro lado a influência do mesmo no custo social e no bem estar dos residentes nos arredores dessas infraestruturas. Os resultados confirmam as externalidades associadas ao transporte aéreo em São Tomé e Príncipe consoante as avaliações das operadoras em STP com estimativa de crescer na projeção futura com o aumento triplicado das frequências de voo atual, ou com o surgimento de novas rotas, com possível liberalização deste sector no mercado africano. A questão ambiental é uma questão de sustentabilidade para STP, atendendo que o País tem como fonte económica a agricultura, a pesca e o turismo.
- Importance of periodic CPCP revisions in the evaluation and improvement of the programPublication . Lopes, Hugo Samuel Marinho; Silva, Abílio Manuel Pereira da; Gamboa, Pedro VieiraIn the aeronautic sector, corrosion has been a severe and recurrent problem, mostly since the introduction of metals in aircraft structures and components. This type of damage can affect the structure's integrity, putting in question the airworthiness and safety of the aircraft. History shows us numerous, well-documented aviation accidents, where corrosion was a factor that led to a system failure. Even though improvements have been made, over the years, in the design and manufacturing of new aircrafts, including the use of more corrosion-resistant materials, operators should have a good Corrosion Prevention and Control Program (CPCP) in place throughout the life of the aircraft, achieved through the experience obtained by the operator during the operation of the aircraft. This dissertation exposes the importance of periodic revisions of the aircraft’s CPCP in the fight against corrosion. This research comes from the need of a business jet aircraft operator, NetJets Europe, to reduce maintenance costs related to corrosion and improve aircraft availability. In this work, a segmented and efficient methodology for a comprehensive CPCP revision is described, in order to improve the operator’s economic and operational status. A corrosion findings database was created for each NetJets Europe fleet, in order to obtain an overview of the most affected areas. A complementary study was also performed, in terms of maintenance costs and labor hours, with the objective of finding the most critical areas, structures or components, that needed to be selected for extensive root cause analyses. During the root cause analyses, the aircraft manufacturers and Original Equipment Manufacturers (OEMs) were contacted for a better assessment of the problems. The results show the importance of these analyses in order to find the best countermeasures possible, which can reduce maintenance costs and improve aircraft availability, while maintaining or improving the safety level.
- Inflammatory effects of high and moderate intensity exercisePublication . Cerqueira, Érica Orlando Bompastor; Lourenço, Olga Maria Marques; Marinho, Daniel A.; Neiva, Henrique P.Background: Exercise leads to a robust inflammatory response mainly characterized by the mobilization of leukocytes and an increase in circulating inflammatory mediators produced by immune cells and directly from the active muscle tissue. Both positive and negative effects on immune function and susceptibility to minor illnesses were observed. While engaging in moderate activity may enhance immune function above sedentary levels, excessive amounts of prolonged, high-intensity exercise may impair immune function. The goal of this systematic review was to clarify the inflammatory effects in response to different exercise intensities. Methods: A systemic search examining exercise and inflammation was performed on PubMed and completed on July 31st, 2017. Eighteen articles were included, and their quality was assessed. The specific components that were examined included circulating blood levels of cytokines, leukocytes, creatine kinase (CK) and C-reactive protein (CRP). Results: Most of the intervention studies showed changes in the assessed biomarkers, although these changes were not always consistent. White blood cells (WBC) had an increase immediately after intensive exercise (> 64 % VO2max), without alteration after moderate exercise (46 - 64% VO2max). The results suggested an elevation of the pro-inflammatory cytokines, namely IL-6, followed by an elevation of IL-10 that were more evident after intensive exercise bouts. CRP increased both after intense and moderate exercise, with peak increases up to 28h. CK increased only after intensive and long exercitation. Conclusion: It is suggested a particularly caution due to increased susceptibility to illness when higher exercise intensities are used.