35 resultados para CULTURAL PROPERTY PROTECTION
em Universidade do Minho
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Dissertação de mestrado em Património e Turismo Cultural
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Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos
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Tese de Doutoramento Engenharia Têxtil
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Doctoral Thesis for PhD degree in Industrial and Systems Engineering
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Dissertação de mestrado em Direito dos Contratos e da Empresa
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The synthesis of a novel fused nitrogen heterocycle, benzoquinolone, for evaluation as a photocleavable protecting group is described for the first time, by coupling to model amino acids (alanine, phenylalanine and glutamic acid). Conversion of the phenylalanine ester conjugate to the thionated derivative was accomplished by reaction with Lawesson’s reagent. Photocleavage studies of the carbonyl and thiocarbonyl benzoquinolone conjugates in various solvents and at different wavelengths (300, 350 and 419 nm) showed that the most interesting result was obtained at 419 nm for the thioconjugate, revealing that the presence of the thiocarbonyl group clearly improved the photolysis rates, giving practicable irradiations times for the release of the amino acids (less than 1 minute).
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Dissertação de mestrado em European and Transglobal Business Law
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Partindo da configuração de um novo ecossistema comunicacional, que tem na internet o seu epicentro, procura-se refletir sobre a influência do mesmo na socialização de crianças e jovens, através da análise da presença de literatura infantojuvenil neste novo media. A observação de que os dispositivos de comunicação digital alargam as oportunidades de acesso à informação entre cidadãos que falam, pensam e sentem em língua portuguesa, foca a questão no espaço cultural da lusofonia.
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[Excerto] Lusofonia e Interculturalidade. Promessa e Travessia debate a questão lusófona, em três aspetos principais. No atual contexto da globalização, que é uma realidade de cariz eminentemente económico-financeiro, comandada pelas tecnologias da informação, esta obra interroga o sentido das narrativas (literárias e mediáticas, e também das narrativas de histórias de vida) sobre a construção de uma comunidade geocultural transnacional e transcontinental lusófona. Interroga, igualmente, as políticas da língua e da comunicação como combate simbólico pela afirmação de uma comunidade plural, na diversidade de povos e culturas lusófonas. E interroga, ainda, a complexidade do movimento de interpenetração das culturas, o qual, com gradações diversas, que compreendem colonialismo, neocolonialismo e pós-colonialismo, na relação entre povos, traduz o encontro, a assimilação e a dominação, na interação entre nós e o outro. Sendo este o plano geral da obra Lusofonia e Interculturalidade, misturam-se nela distintos regimes do olhar, específicos das Ciências Sociais e Humanas, que vão da sócio-antropologia, à psicologia social, à ciência política e às ciências da comunicação, e da linguística, aos estudos literários, à história e às ciências da educação.
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Dissertação de mestrado em Design e Marketing
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Dissertação de mestrado em Economia Monetária, Bancária e Financeira
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Dissertação de mestrado em Economia Monetária, Bancária e Financeira
Organic-inorganic hybrid sol-gelcoatings for metal corrosion protection: a review of recent progress
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This paper is a review of the most recent and relevant achievements (from 2001 to 2013) on the development of organic–inorganic hybrid (OIH) coatings produced by sol–gel-derivedmethods to improve resistance to oxidation/corrosion of different metallic substrates and their alloys. This review is focused on the research of OIH coatings based on siloxanes using the sol–gel process conducted at an academic level and aims to summarize the materials developed and identify perspectives for further research. The fundamentals of sol–gel are described, including OIH classification, the interaction with the substrate, their advantages, and limitations. The main precursors used in the synthesis ofOIHsol–gel coatings for corrosion protection are also discussed, according to the metallic substrate used. Finally, a multilayer system to improve the resistance to corrosion is proposed, based on OIH coatings produced by the sol–gel process, and the future research challenges are debated.
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The barrier effect and the performance of an organic–inorganic hybrid (OIH) sol–gel coating are highlydependent on the coating deposition method as well as processing conditions. In this work, studies onthe influence of experimental parameters using the dip coating method were performed. Factors suchas residence time (Rt), a curing step between each dip step and the number of layers of sol–gel OIHfilms deposited on HDGS to prevent corrosion in highly alkaline environments were studied. These OIHcoatings were obtained using a functionalized siloxane, 3-isociantepropyltriethoxysilane that reactedwith a diamino-functionalized oligopolymer (Jeffamine®D-230). The barrier efficiency of OIH coatings insimulated concrete pore solutions (SCPS) was assessed in the first moments of contact, by electrochemicalimpedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings inSCPS was monitored during eight days by macrocell current density. The morphological characterizationof the surface was performed by scanning electronic microscopy before and after exposure to SCPS.Glow discharge optical emission spectroscopy was used to obtain quantitative composition profiles toinvestigate the thickness of the OIH coatings as a function of the number of layers deposited and theinfluence of the Rt in the coating thickness.
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Organic-inorganic hybrid (OIH) sol-gel coatings based on ureasilicates (U(X)) have promising properties for use as eco-friendly coatings on hot dip galvanized steel (HDGS) and may be considered potential substitutes for pre-treatment systems containing Cr(VI). These OIH coatings reduce corrosion activity during the initial stages of contact of the HDGS samples with highly alkaline environments (cementitious media) and allow the mitigation of harmful effects of an initial excessive reaction between cement pastes and the zinc layer. However, the behavior of HDGS coated with U(X) in the presence of chloride ions has never been reported. In this paper, the performance of HDGS coated with five different U(X) coatings was assessed by electrochemical measurements in chloride-contaminated simulated concrete pore solution (SCPS). U(X) sol-gel coatings were produced and deposited on HDGS by a dip coating method. The coatings performance was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization curves measurements, macrocell current density and polarization resistance in contact with chloride-contaminated SCPS. The SEM/EDS analyses of the coatings before and after the tests were also performed. The results showed that the HDGS samples coated with the OIH coatings exhibited enhanced corrosion resistance to chloride ions when compared to uncoated galvanized steel.