Made available in DSpace on 2014-10-09T12:30:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:31Z (GMT). No. of bitstreams: 1 01046.pdf: 5382760 bytes, checksum: a51a7e739db803d25ebaa7a550e5d8b0 (MD5) / Dissertacao (Mestrado) / IEA/D / University of Illinois Urbana - Champaign, Illinois

Made available in DSpace on 2014-10-09T12:38:20Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:43Z (GMT). No. of bitstreams: 1 05682.pdf: 7598679 bytes, checksum: 0a8e36b4d2b6ba00958df86a2415829e (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:28:18Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:45Z (GMT). No. of bitstreams: 0 / Foram desenvolvidas embalagens biodegradáveis ativas tipo espuma, obtidas a partir de fécula de mandioca, capazes de aumentar a vida-de-prateleira de frutas minimamente processadas. Para tanto, agentes ativos que evitam a proliferação de fungos, a perda de peso e, também, forneçam uma indicação visual (mudança de cor da embalagem) da qualidade do produto embalado, foram adicionados às embalagens de fonte renovável. As espumas foram obtidas pelos processos de extrusão e termoprensagem de uma massa de fécula, gel (fécula suspensa em água) e aditivos (plastificantes e/ou agentes ativos). As formulações de espumas variaram quanto: ao tipo e concentrações de plastificantes (glicerol e polietilenoglicol PEG 300); às quantidades de sólido (fécula de mandioca em pó); aos diferentes tratamentos da fécula (modificações química por acetilação e físicas irradiação e pré-gelatinização); à procedência da fécula (da Bahia e do Paraná); ao reaproveitamento de espumas descartadas; às diferentes concentrações de agentes ativos (ácido l-ascórbico, cloreto de cálcio, sorbato de potássio e permanganato de potássio) e quanto à adição de corantes naturais (extratos de beterraba e repolho roxo). Foram avaliadas, principalmente, as propriedades mecânicas e de barreira das diferentes formulações de espumas de fécula de mandioca. Os resultados indicaram que quanto maior a concentração de fécula mais resistente é a espuma. As espumas contendo o plastificante PEG 300 se mostraram bastante flexíveis, apresentaram boa resistência à ruptura e absorveram pouca água. A pré-gelatinização da fécula proporcionou melhores propriedades mecânicas e de barreira para as espumas em relação aos outros tratamentos dados à fécula de mandioca. Já a adição de agentes ativos à massa não proporcionou tais melhoras às embalagens. As espumas de fécula de mandioca produzidas pelo processo de extrusão seguido de termoprensagem foram mais resistentes à ruptura do que as produzidas somente por termoprensagem. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Made available in DSpace on 2014-10-09T12:38:20Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:43Z (GMT). No. of bitstreams: 1 05682.pdf: 7598679 bytes, checksum: 0a8e36b4d2b6ba00958df86a2415829e (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:30:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:31Z (GMT). No. of bitstreams: 1 01046.pdf: 5382760 bytes, checksum: a51a7e739db803d25ebaa7a550e5d8b0 (MD5) / Dissertacao (Mestrado) / IEA/D / University of Illinois Urbana - Champaign, Illinois

Řešenou součástí je část kanálu pro odpadové odstřižky tiskařského stroje. Relativně jednoduchá součást vhodná k výrobě tvářením za studena. Diplomová práce navrhuje zhotovení komponenty lisováním. Po shrnutí základních teorií dále navrhuje varianty výroby. Pro vybranou sestavuje technologický postup a navrhuje kroky tváření. Návazně odvozuje návrh konstrukce postupového nástroje. V neposlední řadě se věnuje ekonomickému vyhodnocení výroby, ročnímu výrobnímu množství a vypočítává bod zvratu pro dané řešení.

The thesis presents a proposal of production of a molded part from the aluminum alloy of group 2024 (dural). Based on the theoretical study and the requirements of the company was designed a cutting tool with a rounded edge for cutting the unfolded shape of the part on the eccentric press LEN 40 C. A new forming tool from textite material for fluid press Quintus QFC was designed. The parts of the cutting tool were designed primarily from normalized (purchased) parts. Manufactured punch and shearing die are made of commonly available tool steels and processed on the attached drawings. The result of the thesis is a recommendation to invest in a specialized workplace for the production of a unfolded shape and reduction of laboriousness adjusting after forming.

Induced attack was studied under three conditions: (1) paired experimentally naive rats were exposed to intense electrical shock; (2) experimental subjects, previously trained to respond on a fixed vii ratio of six responses for liquid food reinforcement, were paired with target animals with the reinforcement contingency in effect; (3) experimental subjects were given a history of responding on a fixed ratio of six responses for positive reinforcement in the presence of shock, and finally this group was paired with experimentally naive targets when both the reinforcement and shock variables were present. Pairing experimental animals without shock did not cause attack, nor was bar-pressing behavior appreciably disrupted. Only when electrical shock was imposed upon pairs did attack occur. Furthermore, attack behavior severely reduced operant responding and there appeared to be no recovery of response rates over several sessions.