Comp��sitos polim��ricos a base de fibras de licuri: efeitos da hibridiza����o e do envelhecimento ambiental acelerado

The gradual replacement of conventional materials by the ones called composite materials is becoming a concern about the response of these composites against adverse environmental conditions, such as ultraviolet radiation, high temperature and moist. Also the search for new composite using natural fibers or a blend of it with synthetic fibers as reinforcement has been studied. In this sense, this research begins with a thorough study of microstructural characterization of licuri fiber, as a proposal of alternative reinforcement to polymeric composites. Thus, a study about the development of two composite laminates was done. The first one, involving only the fiber of licuri and the second comprising a hybrid composite based of fiber glass E and the fiber of licuri, in order to know the performance of the fiber when of fiber across the hybridization process. The laminates were made in the form of plates using the tereft��lica ortho-polyester resin as matrix. The composite laminate made only by licuri fiber had two reinforcing fabric layers of unidirectional licuri and the hybrid composite had two reinforcing layers of unidirectional licuri fabric and three layers of fiber short glass-E mat. Finally, both laminates was exposed to aging acceleration in order to study the influence of environmental degradation involving the mechanical properties and fracture characteristics thereof. Regarding the mechanical properties of composites, these were determined through uniaxial tensile tests, uniaxial compression and three bending points for both laminates in original state, and uniaxial tensile tests and three bending points after accelerated aging. As regards the study of structural degradation due to aging of the laminates, it was carried out based on microscopic analysis and microstructure, as well as measuring weight loss. The characteristics of the fracture was performed by macroscopic and microscopic (optical and SEM) analysis. In general, the laminated composites based on fiber licuri showed some advantages in their responses to environmental aging. These advantages are observed in the behavior related to stiffness as well as the microstructural degradation and photo-oxidation processes. However, the structural integrity of this laminate was more affected in case the action of uniaxial tensile loads, where it was noted a lower rate of withholding his last resistance property

Efeitos do envelhecimento ambiental acelerado em comp��sitos polim��ricos

The advantages of the use of vegetable fibers on the synthetic fibers, such as glass fibers, in the reinforcements in composites are: low cost, low density, good tenacity, good thermal properties and reduced use of instruments for their treatment or processing. However, problems related to poor performance of some mechanical natural fibers, have hindered its direct use in structural elements. In this sense, the emergence of alternative materials such as hybrids composites, involving natural and synthetic fibers, has been encouraged by seeking to improve the performance of structural composites based only on natural fibers. The differences between the physical, chemical and mechanical properties of these fibers, especially facing the adverse environmental conditions such as the presence of moisture and ultraviolet radiation, is also becoming a concern in the final response of these composites. This piece of research presents a comparative study of the strength and stiffness between two composite, both of ortoftalic polyester matrix, one reinforced with fibers of glass-E (CV) and other hybrid reinforced with natural fibers of curau�� and fiberglass-E (CH). All the comparative study is based on the influence of exposure to UV rays and steam heated water in composites, simulating the aging environment. The conditions for the tests are accelerated through the use of the aging chamber. The composites will be evaluated through tests of uniaxial static mechanical traction and bending on three points. The composite of glass fiber and hybrid manufacturing industry are using the rolling manual (hand lay-up) and have been developed in the form of composites. All were designed to meet possible structural applications such as tanks and pipes. The reinforcements used in composites were in the forms of short fiber glass-E quilts (450g/m2 - 5cm) of continuous wires and fuses (whose title was of 0.9 dtex) for the curau�� fibers. The results clearly show the influence of aging on the environmental mechanical performance of the composite CV and CH. The issues concerning the final characteristics of the fracture for all types of cargoes studied were also analyzed

Envelhecimento ambiental acelerado em PRF a base de tecidos h��bridos kevlar/vidro: propriedades e instabilidade estrutural

There are a number of damaging mechanisms that various materials can suffer in service. However, when working with polymer composite materials, this is something that requires analysis, especially when exposed to adverse environmental conditions. Thus, the objective of the present thesis is the study of the direct influence of environmental aging and the form of hybridization of the reinforcement woven on the structural stability, surfacedegradation and fracture process of polymer composites laminates. For this, the development of two polymer composite laminates was necessary, where one of them was reinforced with a bi-directional woven with hybrid strandsofkevlar-49/glass-Efibers, and the other also with a bi-directionalwoven, however with weft and warpformed of alternating strandsof Kevlar-49 fibers and glass-E fiber The reinforcementwoven are industrially manufactured. Both laminates use a polyester resin as a matrixand are made up of four layers each. All laminates were industrially prepared by the hand lay-up method of manufacturing. To do this, test specimens were manufactured of the respective laminates and submitted to environmental aging accelerated through the aging chamber. They were exposed to alternating cycles of UV radiation and moisture (heated steam) for a standard defined period. At the end of the exposure period the specimens were subjected to mechanical tests of uniaxial tensile and bending in three points and to the characterizationsof the fracture and surface deterioration. In addition, they were submitted to a structural degradation assessment by the measurement of mass variation technique (MMVT) and the measurement of thickness variation technique (MTVT), this last technique being developed in this thesis. At the end of the analysis it was observed that the form of hybridization of the reinforcement woven and the aging process directly influence with losses or gain in mechanical properties, with losses in the structural degradation and in the formation and propagation of damage mechanism of the developedcomposite laminates

Laminados comp��sitos de PRFV: efeitos da descontinuidade geom��trica e do envelhecimento ambiental acelerado

The growing demand in the use of composite materials necessitates a better understanding of its behavior related to many conditions of loading and service, as well as under several ways of connections involved in mechanisms of structural projects. Within these project conditions are highlighted the presence of geometrical discontinuities in the area of cross and longitudinal sections of structural elements and environmental conditions of work like UV radiation, moisture, heat, leading to a decrease in final mechanical response of the material. In this sense, this thesis aims to develop studies detailed (experimental and semi-empirical models) the effects caused by the presence of geometric discontinuity, more specifically, a central hole in the longitudinal section (with reduced cross section) and the influence of accelerated environmental aging on the mechanical properties and fracture mechanism of FGRP composite laminates under the action of uniaxial tensile loads. Studies on morphological behavior and structural degradation of composite laminates are performed by macroscopic and microscopic analysis of affected surfaces, in addition to evaluation by the Measurement technique for mass variation (TMVM). The accelerated environmental aging conditions are simulated by aging chamber. To study the simultaneous influence of aging/geometric discontinuity in the mechanical properties of composite laminates, a semiempirical model is proposed and called IE/FCPM Model. For the stress concentration due to the central hole, an analisys by failures criteria were performed by Average-Stress Criterion (ASC) and Point-Stress Criterion (PSC). Two polymeric composite laminates, manufactured industrially were studied: the first is only reinforced by short mats of fiberglass-E (LM) and the second where the reinforced by glass fiber/E comes in the form of bidirectional fabric (LT). In the conception configurations of laminates the anisotropy is crucial to the final mechanical response of the same. Finally, a comparative study of all parameters was performed for a better understanding of the results. How conclusive study, the characteristics of the final fracture of the laminate under all conditions that they were subjected, were analyzed. These analyzes were made at the macroscopic level (scanner) microscope (optical and scanning electron). At the end of the analyzes, it was observed that the degradation process occurs similarly for each composite researched, however, the LM composite compared to composite LT (configurations LT 0/90�� and LT ��45��) proved to be more susceptible to loss of mechanical properties in both regarding with the central hole as well to accelerated environmental aging

Envelhecimento ambiental em comp��sitos polim��ricos �� base de tecidos de refor��os h��bridos

The utilization of synthetic fibers for plastic reinforcement is more and more frequent and this growing interest requires that their mechanic behavior under the most variable conditions of structural applications be known. The use of such materials in the open and exposed to the elements is one of them. In this case, it becomes extremely necessary to study their mechanical properties (strength, stiffness) and the mechanism of fracture by which the environment aging them out. In order to do that, the material must be submitted to hot steam and ultraviolet radiation exposure cycles, according to periods of time determined by the norms. This study proposal deals with the investigation of accelerated environmental aging in two laminated polymeric composites reinforced by hybrid woven made up of synthetic fibers. The configurations of the laminated composites are defined as: one laminate reinforced with hybrid woven of glass fibers/E and Kevlar fibers/49 (LHVK) and the other laminate is reinforced with hybrid tissue of glass fibers/E and of carbon fibers AS4 (LHVC). The woven are plane and bidirectional. Both laminates are impregnated with a thermofix resin called Derakane 470-300 Epoxy Vinyl-Ester and they form a total of four layers. The laminates were industrially manufactured and were made through the process of hand-lay-up. Comparative analyses were carried out between their mechanical properties by submitting specimen to uniaxial loading tractions and three-point flexion. The specimen were tested both from their original state, that is, without being environmentally aging out, and after environmental aging. This last state was reached by using the environmental aging chamber

Estudo comparativo de nanocomp��sitos de polipropileno modificado sob condi����es de envelhecimento ambiental e acelerado

Disserta����o (Mestrado em Tecnologia Nuclear)

Comp��sitos polim��ricos a base de fibras de licuri: efeitos da hibridiza����o e do envelhecimento ambiental acelerado

The gradual replacement of conventional materials by the ones called composite materials is becoming a concern about the response of these composites against adverse environmental conditions, such as ultraviolet radiation, high temperature and moist. Also the search for new composite using natural fibers or a blend of it with synthetic fibers as reinforcement has been studied. In this sense, this research begins with a thorough study of microstructural characterization of licuri fiber, as a proposal of alternative reinforcement to polymeric composites. Thus, a study about the development of two composite laminates was done. The first one, involving only the fiber of licuri and the second comprising a hybrid composite based of fiber glass E and the fiber of licuri, in order to know the performance of the fiber when of fiber across the hybridization process. The laminates were made in the form of plates using the tereft��lica ortho-polyester resin as matrix. The composite laminate made only by licuri fiber had two reinforcing fabric layers of unidirectional licuri and the hybrid composite had two reinforcing layers of unidirectional licuri fabric and three layers of fiber short glass-E mat. Finally, both laminates was exposed to aging acceleration in order to study the influence of environmental degradation involving the mechanical properties and fracture characteristics thereof. Regarding the mechanical properties of composites, these were determined through uniaxial tensile tests, uniaxial compression and three bending points for both laminates in original state, and uniaxial tensile tests and three bending points after accelerated aging. As regards the study of structural degradation due to aging of the laminates, it was carried out based on microscopic analysis and microstructure, as well as measuring weight loss. The characteristics of the fracture was performed by macroscopic and microscopic (optical and SEM) analysis. In general, the laminated composites based on fiber licuri showed some advantages in their responses to environmental aging. These advantages are observed in the behavior related to stiffness as well as the microstructural degradation and photo-oxidation processes. However, the structural integrity of this laminate was more affected in case the action of uniaxial tensile loads, where it was noted a lower rate of withholding his last resistance property

Efeitos da radia����o uv, temperatura e vapor aquecido nos comp��sitos polim��ricos: monitoramento, instabilidade estrutural e fratura

The application of composite materials and in particular the fiber-reinforced plastics (FRP) has gradually conquered space from the so called conventional materials. However, challenges have arisen when their application occurs in equipment and mechanical structures which will be exposed to harsh environmental conditions, especially when there is the influence of environmental degradation due to temperature, UV radiation and moisture in the mechanical performance of these structures, causing irreversible structural damage such as loss of dimensional stability, interfacial degradation, loss of mass, loss of structural properties and changes in the damage mechanism. In this context, the objective of this thesis is the development of a process for monitoring and modeling structural degradation, and the study of the physical and mechanical properties in FRP when in the presence of adverse environmental conditions (ageing). The mechanism of ageing is characterized by controlled environmental conditions of heated steam and ultraviolet radiation. For the research, it was necessary to develop three polymer composites. The first was a lamina of polyester resin reinforced with a short glass-E fiber mat (representing the layer exposed to ageing), and the other two were laminates, both of seven layers of reinforcement, one being made up only of short fibers of glass-E, and the other a hybrid type reinforced with fibers of glass-E/ fibers of curaua. It should be noted that the two laminates have the lamina of short glass-E fibers as a layer of the ageing process incidence. The specimens were removed from the composites mentioned and submitted to environmental ageing accelerated by an ageing chamber. To study the monitoring and modeling of degradation, the ageing cycles to which the lamina was exposed were: alternating cycles of UV radiation and heated steam, a cycle only of UV radiation and a cycle only of heated steam, for a period defined by norm. The laminates have already undergone only the alternating cycle of UV and heated steam. At the end of the exposure period the specimens were subjected to a structural stability assessment by means of the developed measurement of thickness variation technique (MTVT) and the measurement of mass variation technique (MMVT). Then they were subjected to the mechanical tests of uniaxial tension for the lamina and all the laminates, besides the bending test on three points for the laminates. This study was followed by characterization of the fracture and the surface degradation. Finally, a model was developed for the composites called Ageing Zone Diagram (AZD) for monitoring and predicting the tensile strength after the ageing processes. From the results it was observed that the process of degradation occurs Abstract Raimundo Nonato Barbosa Felipe xiv differently for each composite studied, although all were affected in certain way and that the most aggressive ageing process was that of UV radiation, and that the hybrid laminated fibers of glass-E/curaua composite was most affected in its mechanical properties

Jornalismo ambiental, envelhecimento demogr��fico e universidade aberta �� terceira idade: a tese do empoderamento

The world is aging. This subject is becoming more and more present on the communication media. The future journalists must be made aware of this phenomena that involves a important change in the society. One of the ways can be the study of the empowerment and Social Capital Formation techniques, using the new Information and Communication Technologies, or following the example of the Open Universities to the Third Age that are appearing all over the world. In this article we���ll study the case of ���Programa Universitario para Mayores��� (University Program for the Grown ups), at Seville University (Spain).

Jornalismo ambiental, envelhecimento demogr��fico e universidade aberta �� terceira idade: a tese do empoderamento

This paper proposes a reflection of media���s role and its relationship with global phenomena of demographic aging. From a critical point of view of empowerment���s concepts and social capital, it suggests that journalists can give more visibility to the perspective of senior citizens��� inclusion in social life through a better use of ICTs and the insertion of more diverse subjects such as universities opened to Third Age. It suggests also that this theme should be developed in training future professionals, so the media can enhance others representations of excluded groups with more social responsibility.

Desenvolvimento de cosm��tico contendo ��cido Alfa-Lip��ico para preven����o de altera����es da pele e do envelhecimento cut��neo

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Influ��ncias do envelhecimento e do ambiente sobre a progress��o da encefalite experimental por arbov��rus Piry em modelo murino: mudan��as morfol��gicas microgliais e altera����es comportamentais

O enriquecimento ambiental e os efeitos do envelhecimento sobre as altera����es morfol��gicas das micr��glias e no comportamento foram investigados em modelo murino de encefalite sub-letal por arbov��rus. Para medir poss��veis influ��ncias da idade e do ambiente sobre a progress��o da encefalite, camundongos su����os albinos f��meas de 2 meses de idade foram mantidos em Ambiente Padr��o (AP) ou em Ambiente Enriquecido (AE), durante: 6 meses (Adulto - A) e 16 meses (Senil ���S). Ap��s os testes comportamentais, os camundongos A e S foram inoculados intranasalmente com igual volume de homogenado de c��rebro de camundongo infectado pelo v��rus Piry (Py) ou homogenado de c��rebro de camundongo normal. Oito dias ap��s a inocula����o (8DPI), quando os primeiros testes comportamentais revelaram as altera����es relacionadas �� doen��a, os c��rebros foram seccionados e inumomarcados seletivamente para IBA-1 e ant��genos virais. Aos 20 ou 40DPI, os animais restantes foram testados comportamentalmente e processados para os mesmos marcadores e nenhum sinal neuropatol��gico foi detectado. Em camundongos adultos infectados o ambiente padr��o (APPyA), a atividade de burrowing diminuiu e se recuperou rapidamente (8-10DPI), a atividade de campo aberto (20-40DPI), mas manteve-se inalterado em animais da mesma idade e de ambiente enriquecido (AEPyA). Em contraste animais senis tanto de ambiente enriquecido (AEPyS) quanto de ambiente empobrecido (APPyS) reduzem significativamente a atividade de burrowing em todas janelas. A encefalite causada pelo virus Piry, induziu perdas olfativas transit��rias em animais APPyA e AEPyA, mas permanents em APPyS e AEPyS. A imunomarca����o para os ant��genos viral do Piry atingiram seu pico no par��nquima do SNC aos 5 e 6DPI e desapareceu aos 8DPI. Todas as reconstru����es tridimensionais das micr��glias, foram realizadas aos 8DPI. Mudan��as Microgliais foram significativamente mais graves em camundongos adultos do que em camundongos senis, mas os animais AE parecem recuperar a morfologia microglia homeost��tica mais cedo do que os animais de AP. Os efeitos ben��ficos do AE foram menores em camundongos envelhecidos.

O papel da Universidade Aberta �� Terceira Idade na educa����o ambiental

Population aging and environmental protection have gained special importance after the economic, demographic and social recent changes. The objective of this paper was to promote theoretical and reflective review with emphasis on convergence between sustainable development and educational activities promoted by the University of the Third Age. We conducted a literature review to give full articles from the descriptors: aged, sustainable development indicators and environmental protection, published in English, Spanish and Portuguese, between January 1994 and June 2014, in national and international journals on the basis LiIlacs, Bireme and Medline. We used systematic data collection for sample analysis. The results indicate that the University of the Third Age develops teaching, research and extension, through actions based on aging and educational assumptions. In this context, environmental education is presented as a pedagogical process capable of awakening the critical capacity of the elderly, making it active social worker and leading him to a cultural design which ensures establishment of sustainable harmonious relationship with nature. It was concluded that the University of the Third Age contributes to initiatives that emphasize the relationships between systems and economic processes or social and natural processes, generating the construction of social values, knowledge, skills, attitudes and skills aimed at the conservation of the environment.

A EDUCA����O AMBIENTAL NO CONTEXTO DA FORMA����O DO AGENTE SOCIAL DA TERCEIRA IDADE COMO EDUCADOR

A id��ia do envelhecimento como decl��nio da exist��ncia humana come��a a perder sentido nas sociedades contempor��neas e dar espa��o a uma outra concep����o da terceira idade. Neste contexto, a Universidade Metodista de S��o Paulo, campus Vergueiro S��o Bernardo do Campo, oferece o curso Universidade Livre da Terceira Idade, que tem como finalidade a forma����o de agentes sociais. Um dos eixos desse curso �� a educa����o ambiental. Meio ambiente �� aqui entendido como entorno do indiv��duo, sendo ele natural, constru��do e s��cio-cultural, com suas institui����es, saberes e valores. Assim, o educador ambiental apresenta conhecimentos sobre as quest��es ambientais e habilidade ao lidar com pessoas dos mais diferentes contextos. Nesta perspectiva, o agente social da terceira idade desenvolve os atributos necess��rios para atua����o enquanto educador ambiental, uma vez que trabalha o saber ambiental necess��rio ��s a����es de interven����o e consolida sua forma����o pessoal. Este trabalho objetiva analisar a percep����o ambiental dos alunos da universidade da terceira idade ao iniciar o curso, dentro do m��dulo de educa����o ambiental. Verificar se os conte��dos e metodologias utilizadas na disciplina de educa����o ambiental contribuem para a forma����o do agente social da terceira idade e para sua atua����o como educador ambiental. O corpo te��rico desta pesquisa foi composto pelo conceito de complexidade de Edgar Morin, as id��ias de meio ambiente de Enrique Leff, a concep����o de educa����o de Paulo Freire e a compreens��o de educa����o ambiental de Marcos Reigota. Como instrumentos metodol��gicos, foram utilizados t��cnicas de an��lise de documentos, question��rios e grupo focal. A apresenta����o e interpreta����o dos dados coletados sugerem a viabilidade da atua����o do indiv��duo da terceira idade como educador ambiental nas a����es de interven����o em sua realidade local.

A EDUCA����O AMBIENTAL NO CONTEXTO DA FORMA����O DO AGENTE SOCIAL DA TERCEIRA IDADE COMO EDUCADOR

A id��ia do envelhecimento como decl��nio da exist��ncia humana come��a a perder sentido nas sociedades contempor��neas e dar espa��o a uma outra concep����o da terceira idade. Neste contexto, a Universidade Metodista de S��o Paulo, campus Vergueiro S��o Bernardo do Campo, oferece o curso Universidade Livre da Terceira Idade, que tem como finalidade a forma����o de agentes sociais. Um dos eixos desse curso �� a educa����o ambiental. Meio ambiente �� aqui entendido como entorno do indiv��duo, sendo ele natural, constru��do e s��cio-cultural, com suas institui����es, saberes e valores. Assim, o educador ambiental apresenta conhecimentos sobre as quest��es ambientais e habilidade ao lidar com pessoas dos mais diferentes contextos. Nesta perspectiva, o agente social da terceira idade desenvolve os atributos necess��rios para atua����o enquanto educador ambiental, uma vez que trabalha o saber ambiental necess��rio ��s a����es de interven����o e consolida sua forma����o pessoal. Este trabalho objetiva analisar a percep����o ambiental dos alunos da universidade da terceira idade ao iniciar o curso, dentro do m��dulo de educa����o ambiental. Verificar se os conte��dos e metodologias utilizadas na disciplina de educa����o ambiental contribuem para a forma����o do agente social da terceira idade e para sua atua����o como educador ambiental. O corpo te��rico desta pesquisa foi composto pelo conceito de complexidade de Edgar Morin, as id��ias de meio ambiente de Enrique Leff, a concep����o de educa����o de Paulo Freire e a compreens��o de educa����o ambiental de Marcos Reigota. Como instrumentos metodol��gicos, foram utilizados t��cnicas de an��lise de documentos, question��rios e grupo focal. A apresenta����o e interpreta����o dos dados coletados sugerem a viabilidade da atua����o do indiv��duo da terceira idade como educador ambiental nas a����es de interven����o em sua realidade local.