Made available in DSpace on 2016-06-02T19:29:56Z (GMT). No. of bitstreams: 1 5136.pdf: 1469178 bytes, checksum: a0809686f5333526f7e5eb0a69d193b3 (MD5) Previous issue date: 2013-03-15 / Financiadora de Estudos e Projetos / With the purpose of elucidating some aspects concerning the importance of substrate spatial complexity to the ecology of Chironomidae (Diptera) family in Cerrado streams, three field experiments were carried out in Ipameri and Mimoso de Goiás Municipalities, Goiás State, Brazil. These experiments are described in three chapters that compose this thesis i) Temporal dynamics of Chironomidae (Diptera) larvae on substrates with different levels of spatial complexity and roughness in a Central Brazil stream; ii) Is substrate complexity important for Chironomidae (Diptera) larvae to resist hydrological disturbance?; iii) Influence of spatial complexity and roughness on Chironomidae (Diptera) assemblages. Artificial substrates with different complexity and roughness levels were fixed in bed streams for colonization of Chironomidae larvae. Samplings were taken after a period of 30 days. Results indicated that: i) Colonization of substrates by larvae was not influenced by substrate spatial complexity and no patterns of colonization were observed, considering the various ecological guilds; ii) Both complexity and roughness were not sufficient to maintain the abundance of these organisms, evidencing their sensibility to sudden rain events; iii) Spatial complexity and roughness of substrate influenced the structure of Chironomidade assemblages and were two important aspects to the diversity of these organisms. / Buscando esclarecer alguns aspectos a respeito da importância da complexidade espacial do substrato sobre a ecologia de Chironomidae (Diptera) em córregos de baixa ordem do Cerrado brasileiro, foram realizados três experimentos aqui apresentados em três capítulos: i) Dinâmica temporal de Chironomidae (Diptera) em substratos com diferentes complexidades e rugosidades em um riacho do Brasil Central; ii) A complexidade do substrato é importante para as larvas de Chironomidae (Diptera) resistirem à perturbação hídrica?; iii) Influência da complexidade espacial e da rugosidade na assembleia de Chironomidae (Diptera). Os experimentos foram realizados nos municípios de Ipameri e Mimoso de Goiás, ambos situados no Estado de Goiás. Para amostragem das larvas de Chironomidae foram utilizados substratos artificiais com diferentes níveis de complexidade e rugosidade fixados no leito dos riachos para colonização. De forma geral os resultados obtidos indicaram que: i) A colonização dos substratos pelas larvas não foi influenciada pela complexidade espacial do substrato, não sendo observados padrões de colonização, considerando as diferentes guildas ecológicas; ii) Tanto a complexidade quanto a rugosidade do substrato não foram suficientes para a manutenção da abundância das larvas de Chironomidae, evidenciando sua sensibilidade a eventos inesperados de chuva; iii) A complexidade espacial e a rugosidade do substrato afetam a estrutura da assembleia de Chironomidae, sendo dois importantes aspectos para a diversidade destes organismos.

Aluminum alloys have been used for decades in aircraft as they offer a wide range of properties explicitly developed to provide a set of characteristics adapted to structural and non-structural components. However, aircraft components inevitably undergo degradation during service due to their extensive use and exposure to harsh environments. Typical repair methods are either not efficient for large scale repairs due to their low material growth rate, not suitable for field repair or involve the use of high process temperatures. The present research aims at evaluating the cold gas dynamic spray (CGDS) as a potential repair technology to restore Al7075-T6 nose landing gear steering actuator threads found on the Boeing 757 aircraft. Moreover, it studies the suitability of using cold spray to deposit Al2024 material. The influence of process parameters and substrate surface preparation on the material deposition efficiency and resulting microstructural and mechanical repair properties is also evaluated.