759 resultados para elaborazione di immagini metodi di segmentazione filtri per immagini


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In recent years, the asymmetric organocatalysis has been recognized as an independent area of synthetic chemistry, where the goal is the preparation of any chiral molecule in an efficient, rapid, and stereoselective manner. In this context we have synthesized macromolecular catalysts soluble in the reaction conditions and that can finally recovered by simple precipitation and subsequent filtration. In particular different active compounds (9-epi-NH2 hyidroquinine and β –isocupreidine) have been linked to the terminal group of the main chain polyethylene glycol monomethyl ether (PEG-5000). The macromolecular catalysts have been tested in different reactions and the results have been compared with those of the correspondent low molecular compounds.

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One of the key processing parameters in thermoset composites manufacturing is to have an optimum balance between open time and cure time. Long open times followed with a fast cure profile (also referred as snap cure or “hockey stick” shaped profiles) are required on applications like Pultrusion, Filament Winding, Resin Transfer Molding (RTM) and Infusion. In this work, several factors affecting the reactivity of a base line polyurethane formulation were studied. The addition of different components such as internal mold release agents, cross-linker, polyols having different molecular structure and isocyanates having different functionality were studied. A literature search was conducted to identify the main catalyst packages existing in the market. The reactivity of catalyst based on tertiary amines, orgamometallic salts, and co-catalyst of amine-organometallic complexes was characterized. Addition of quelants agents such as thioglycerol and acetyl acetone to delay the catalyst activity were also considered. As a consequence of this work a vast reactivity map was generated. This should guide the formulation designer in future product generations for the further development of the mentioned applications. Recommendations on measurements systems and further areas of exploration are also given.

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Approfondimento di tecniche di controllo ottimo per problemi di regolazione e di inseguimento di modello. Sintesi e implementazione di un algoritmo che si occupi del controllo della dinamica laterale di una vettura attraverso il sistema di aerodinamica mobile.

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