RCAAP - Repositório Científico de Acesso Aberto de Portugal

    O campo da arte segundo Marcel Duchamp

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    O sentido de meta-arte em Duchamp evidencia o facto de a sua obra não ser exclusiva de qualquer forma de expressão artística. A própria natureza da arquitectura, sendo esta motivada pela estética mas também pela utilidade, não será alheia ao sentido da ideia duchampiana na possibilidade de fazer obras que não sejam "de arte", no seu afastamento estratégico a visões puramente esteticizantes, no seu sentido mais estrito. É esta impureza da arquitectura enquanto forma de arte, no sentido que tradicionalmente se atribui à arte no afastamento de qualquer funcionalidade, que torna pertinente, neste contexto, a reflexão sobre Duchamp. Na arquitectura, na relação do processo de projectar com o programa do projecto, o pensamento conceptivo não pode ser alheio a uma lógica, na evidência e inevitabilidade da arte como coisa mental. É na procura do que consistirá, em arte, a ideia de inteligência, que este trabalho se situa. E na ideia duchampiana de fazer obras que não sejam "de arte" encontramos intencionalidade de defender a arte das suas definições, na procura de uma noção de arte que seja sobretudo, na sua relação com a realidade, o campo das suas possibilidades. Nesta dissertação através de Duchamp, encontramos reflexões sobre: a noção de indivíduo; a noção de plasticidade; a relação da arte com a racionalidade; a noção de espaço; a experiência de imaginar; a valorização da subtileza, na importância de entidades ínfimas em detrimento de uma abordagem da realidade na estrita simplificação da racionalidade (na criação duchampiana da ideia de inframince); e, sobretudo através das suas Boites-en-valise, o entendimento da criação artística enquanto o todo de um processo.Duchamp, making art that, simultaneously, is a reflection on what is art about, reveals a aesthetical thought that is not meant to be exclusive of any form of artistic expression. The nature of the architecture itself, being motivated by the aesthetics, but also by the utility, can not be indifferent to the meaning of the duchampian idea of the possibility of making artefacts that are not "of art", in its strategical withdrawal from the purely aesthetical, in its most restrict sense. It is this impurity of the architecture while art form, in the sense that traditionally is attributed to art as being away from any idea of functionality, that becomes pertinent, in this context, the reflection on Duchamp. In architecture, in the relation of the process of the project with its program, the conceptive thought cannot exclude logic, in the evidence and inevitability of art as a mental thing. It is the seek of what consists, in art, the idea of intelligence, that is the aim of this dissertation. And in the duchampian idea of the possibility of making artefacts that are not "of art" we find the purpose to defend art of its definitions, in the seek of a notion of art where art is, over all, in its relation to reality, the field of its possibilities. In this dissertation, through Duchamp, we find reflections on: the notion of individual; the notion of plasticity; the relationship between art and rationality; the notion of space; the experience of imagining; the recognition of subtlety, in the importance of thinnermost entities as an alternative to an approach to the reality in the strict simplification of rationality (in the duchampian creation of the idea of inframince) ; and, mostly through his Boites-en-valise, the understanding of the artistic creation as the whole of a process.Tese de Doutorament

    Crystalline phase characterization of glass-ceramic glazes

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    The firing process of five raw crystalline frits was investigated by means of DTA, XRD, heating microscopy and dilatometry. The chemical composition of the frits was determined by FAAS, to define the main glass-ceramic system of each frit. The final crystalline structure detected for the sintered frits conformed to the temperatures for which transformations were obtained during heating. The existence of a relationship between the crystallization process and sintering behaviour was confirmed. During devitrification, the sintering process stops, confirming that crystalline formation affects the sintering behaviour of the frits. In this case, the thermal properties of the final product are not only dependent on oxide composition but also on the crystalline phases. It was established that the addition of adequate compounds could induce the formation of crystalline phases on some glass-ceramic frits.http://www.sciencedirect.com/science/article/B6TWH-4J2M702-7/1/c8bec9ab22896fa1ec8d049531ca264

    Phase behavior of (polyacrylamides + water) solutions: concentration, pressure and isotope effects

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    Phase diagrams of poly(N-isopropylacrylamide) (PNIPAAM) as well as of hydrophilically-modified copolymers in aqueous solution were determined. A high-accuracy He-Ne Laser scattering technique was used for the detection of operational spinodal (sp) and cloud-point (cp) curves. Polymer concentration was varied from 0.5 to 20 wt.%. In the case of copoly(PNIPAAM/vinylsaccharide) several different chain lengths were considered. Pressure (up to 400 bar) and solvent isotope effects were studied. We predict a closed-loop type phase diagram for the copolymers, which presents an estimated hypercritical point in H2O solutions at Mw~0.5×105, although only lower critical solution temperature (LCST) is experimentally accessible. At lower molecular weights, the solutions are always in the one-phase region.http://www.sciencedirect.com/science/article/B6TG2-43MC9F5-N/1/63fb7dd8bec4ff798723b9bcb318a0a

    Thermal decomposition of solid mixtures of 2-oxy-4,6-dinitramine-s-triazine (DNAM) and phase stabilized ammonium nitrate (PSAN)

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    The thermal decomposition of solid mixtures of 2-oxy-4,6-dinitramine-s-triazine (DNAM) and phase stabilized ammonium nitrate (PSAN) at different mass ratios has been studied. Simultaneous thermal analysis (DSC/TG) and thermomicroscopy have been used. It was found that PSAN promotes the lowering of the decomposition temperature of DNAM. The beginning of this process occurs when both components are in the solid state irrespective of the composition. However, the composition appears as the main factor determining the process progression once initiated. These observations are interpreted in the light of known properties of both DNAM and PSAN. Non-isothermal kinetic analysis, restricted to the early stage of the decomposition process, has been performed for the particular DNAM/PSAN ratios of 50/50 and 60/40. The complexity of the process is evidenced by the impossibility of being described by a kinetic model function other than an empirical one (Sestak-Berggren). Noticeable differences in the apparent Arrhenius parameters were found, indicating remarkable changes in the process over the composition range of the kinetic analysis.http://www.sciencedirect.com/science/article/B6THV-41NK87P-7/1/59e86c459f362dd9303ac81b7d05686

    A method to measure lactate recycling in cultured cells by edited 1H nuclear magnetic resonance spectroscopy

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    http://www.sciencedirect.com/science/article/B6W9V-4PF6B5M-1/1/385b6c0836057ee00a92ea234317f1e

    Analysis of lanthanide induced NMR shifts using a crystal field independent method: application to complexes of tetraazamacrocyclic ligands

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    The linear graphical analysis of the LIS NMR data available for the axially symmetric complexes [Ln(DOTA)]- (M and m isomers), [Ln(DOTP)]5- (pH 10.0, 7.0 and 3) and [Ln(DOTEA)]3+ using the classical crystal field dependent method and a crystal field independent method were compared. As the second method provides ratios of geometric structural terms G rather than G values, the effect of lanthanide contraction was reduced. Thus, the large breaks in plots observed for all nuclei of those systems using the classical method are still present in the plots of the second method, only in a few of the nuclei and much reduced. This shows that the large breaks at the middle of the lanthanide series present in plots of the classical method as well as the anomalies often present for those plots for the Tm and Yb ions are mostly due to changes of the crystal field coefficient A2 0<r2> along the lanthanide series, while both the hyperfine coupling constants and the ratios of geometric terms also change as a result of the lanthanide contraction, leading to small breaks at the middle of the lanthanide series. Analysis of the proton shifts of [Ln(DOTP)] complexes at pH 10, 7 and 3 indicates that protonation of the complexes results in a decrease on the crystal field coefficient. The dipolar shift ratios and absolute shifts obtained were also interpreted in terms of the structural models for those complexes in solution and their available X-ray crystal structures.http://www.sciencedirect.com/science/article/B6TG5-45S49G7-1/1/7fee3ca7ba8b89327bec4ab48419d29

    Lack of bursting electrical activity and intracellular calcium oscillations in glucose-stimulated single rat islets

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    http://www.sciencedirect.com/science/article/B6T5Y-49PK0KM-M1/1/868808b020f37b7932fbbb7f28b3f46

    An approach using thin films as a predictive way to produce new bulk materials

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    The aim of the present work is to produce (TiAl)-based films and characterise them in the as-deposited state and after several heat-treatment cycles with different holding times. The idea is to promote phase transformations of the films towards the intermetallic bulk materials. The structure and mechanical properties of binary films and films alloyed with silver were studied as a function of several heat treatment holding times at 600°C. The room temperature stresses were also evaluated and show that during annealing the stresses move from a compressive to a tensile state. The 18 h heat treatment leads to a sharp hardening of the binary film thought as resulting from a fine precipitation. After 162 h heat treatment the grain size increases, but the intrinsic stresses compromise the ductility results obtained.http://www.sciencedirect.com/science/article/B6TVV-4281174-15/1/32c928a40dc66adafd248309823e16f

    Oxidation of sputtered W-based coatings

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    In this paper, a review of the influence of the addition of different chemical elements to some transition metal nitrides and carbides on their oxidation behaviour will be presented. The role of the addition of [`]reactive elements' (RE) on the type of oxide phases formed, on the morphology of the oxide layers, on the oxidation kinetics and on the oxidation rate is emphasized. Examples of the system W-N/C when Ti, Ni and Si are added, will be shown. The beneficial action of the additional element on oxidation resistance can be due either to the formation of some type of protective oxide layer, apart from the typical oxides formed for those metal compounds, or to the blocking effect to the elemental diffusion, which is due to some type of compound precipitation in the diffusion paths.http://www.sciencedirect.com/science/article/B6TVV-4281174-31/1/0abd9b4610b216161a5f49e1020b9d4

    Non-linear behaviour of large-area avalanche photodiodes

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    The characterisation of photodiodes used as photosensors requires a determination of the number of electron-hole pairs produced by scintillation light. One method involves comparing signals produced by X-ray absorptions occurring directly in the avalanche photodiode with the light signals. When the light is derived from light-emitting diodes in the 400-600 nm range, significant non-linear behaviour is reported. In the present work, we extend the study of the linear behaviour to large-area avalanche photodiodes, of Advanced Photonix, used as photosensors of the vacuum ultraviolet (VUV) scintillation light produced by argon (128 nm) and xenon (173 nm). We observed greater non-linearities in the avalanche photodiodes for the VUV scintillation light than reported previously for visible light, but considerably less than the non-linearities observed in other commercially available avalanche photodiodes.http://www.sciencedirect.com/science/article/B6TJM-45HFC9M-2K/1/447b7168bf09233e9122112c90b89b1
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