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Browsing by Issue Date, starting with "2007-05"

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  • Fractional order dynamical systems and its applications
    Publication . Tenreiro Machado, J. A.; Barbosa, Ramiro; Jesus, Isabel S.; Silva, Manuel; Figueiredo, Lino; Reis, Cecília; Marcos, Maria da Graça; M. Afonso, Luís; Galhano, Alexandra; Duarte, Fernando B.; Lima, Miguel L.; Pires, Eduardo S.; Ferreira, Nuno M. Fonseca
    This article illustrates several applications of fractional calculus (FC) in science and engineering. It has been recognized the advantageous use of this mathematical tool in the modeling and control of many dynamical systems. In this perspective, this paper investigates the use of FC in the following fields:  Controller tuning;  Electrical systems;  Traffic systems;  Digital circuit synthesis;  Evolutionary computing;  Redundant robots;  Legged robots;  Robotic manipulators;  Nonlinear friction;  Financial modeling.
    2007-05Conference object Open access Show more
  • Uma Visão Panorâmica sobre os Robôs com Pernas
    Publication . Silva, Manuel; Tenreiro Machado, J. A.
    1 - Introdução à Robótica - Limitaçõesdos veículos tradicionais - Características dos veículos com pernas e aplicações potenciais - Evolução dos veículos com pernas - Perspectivas de desenvolvimento futuro 2 – Modelo de simulação de robôs multi-pernas - Modelo cinemático - Modelo dinâmico - Modelo do solo - Arquitectura de controlo
    2007-05Conference object Open access Show more
  • SIT (ITS) - Sistemas Inteligentes de Transporte
    Publication . Figueiredo, Lino; Tenreiro Machado, J. A.
    O que é ITS ? Utilização de tecnologias de informação, comunicação e controlo para: Reduzir os congestionamentos de trafego, Melhorar a segurança, Contribuir para a preservação do meio ambiente Melhorar a eficiência de um sistema de transporte.
    2007-05Conference object Open access Show more
  • Unanticipated stereoselectivity in the reaction of primaquine α-aminoamides with substituted benzaldehydes:  A computational and experimental study†
    Publication . Ferraz, Ricardo; Gomes, José R. B.; Oliveira, Eliandre de; Moreira, Rui; Gomes, Paula
    Imidazolidin-4-ones are commonly employed as skeletal modifications in bioactive oligopeptides, either as proline surrogates or for protection of the N-terminal amino acid against aminopeptidase- and endopeptidase-catalyzed hydrolysis. Imidazolidin-4-one synthesis usually involves the reaction of an α-aminoamide moiety with a ketone or an aldehyde to yield an imine, followed by intramolecular cyclization. We have unexpectedly found that imidazolidin-4-one formation is stereoselective when benzaldehydes containing o-carboxyl or o-methoxycarbonyl substituents are reacted with α-aminoamide derivatives of the antimalarial drug primaquine. A systematic computational and experimental study on the stereoselectivity of imidazolidin-4-one formation from primaquine α-aminoamides and various substituted benzaldehydes has been carried out, and they have allowed us to conclude that intramolecular hydrogen-bonds involving the CO oxygen of the o-substituent play a crucial role.
    2007-05-03Journal article Restricted access Show more