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Production of photocatalytic road pavements using TiO2 nanoparticles

Carneiro, Joaquim A. O.; Teixeira, Vasco M. P.; Freitas, Elisabete F.; Fernandes, F.; Azevedo, S. Feyo de; Machado, P.

poster ; Man’s activity and mismanagement of resources conducted to dangerous levels of pollution in water, air and earth and to incalculable deficiencies, harmful to the physical and social health of mankind. Industrial activities, heating systems and road traffic are the main responsibles for the emission of pollutant gases such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). As so, its harmf...


Stability, dynamics of convergence and tuning of observer-based kinetics estima...

Oliveira, Rui Manuel Freitas; Ferreira, E. C.; Azevedo, S. Feyo de

This work discusses issues concerning stability, tuning and dynamics of convergence of observer-based kinetics estimators. The analysis focuses on both continuous and discrete time formulations of the estimation algorithms. Concerning the former, it is shown that, with proper tuning, stability can be guaranteed, while simultaneously imposing a desired quasi-time invariant second order time response for the conv...



Tuning of observer-based estimators: theory and application to the on-line esti...

Perrier, M.; Azevedo, S. Feyo de; Ferreira, E. C.; Dochain, D.

This paper deals with the tuning of observer-based estimators. Initially, these algorithms were designed for estimating on-line kinetic parameters, like specific growth rates, in bioprocesses, and have proved to be very successful in practical applications. Here a systematic tuning approach that allows a decoupled estimation of each parameter and the assignment of the estimator dynamics independently of the pro...


A study on the convergence of observer-based kinetics estimators in stirred tan...

Oliveira, Rui Manuel Freitas; Ferreira, E. C.; Oliveira, Filomena; Azevedo, S. Feyo de

This paper is devoted to the tuning problem of an observer-based algorithm for the on-line estimation of reaction rates in stirred tank bioreactors. The relation between the dynamics of convergence and the tuning procedure is explored. The method proposed imposes a variable second-order dynamics on the convergence of the estimator. This approach is shown to compare favourably with a pole placement based techniq...


Computer-based studies on bioprocess engineering : II - Tools for process opera...

Azevedo, S. Feyo de; Pimenta, Pedro C. C.; Oliveira, Filomena; Ferreira, E. C.

In this paper we review recent advances on the practice and theory of process control with particular emphasis to the operation of bioreactors. We present in detail a case-study on the modelling, model-based identification and adaptive control of fed-batch baker's yeast fermentation.


Model-based estimation of reaction rates in stirred tank bioreactors

Oliveira, Rui Manuel Freitas; Ferreira, E. C.; Azevedo, S. Feyo de

In this paper an adaptive model-based algorithm is proposed for the on-line estimation of reaction rates in stirred tank bioreactors. The main design condition imposes that the observation errors reflecting the mismatch between the estimated parameters and the 'true' values follow second-order dynamics of convergence. The gain matrices are shown to be functions of the state and of user-defined damping coefficie...


A new adaptive scheme for the adaptive linearizing control of bioprocesses

Ferreira, E. C.; Azevedo, S. Feyo de

This work deals with the development of model-based adaptive control algorithms for bioprocess operation. Non-linear adaptive control laws are proposed for single input single output regulation. Parameters are continuously adapted following a new adaptive scheme which ensures second-order dynamics of the parameter error system. A computational study is presented of the application of this theory to baker’s yeas...


Adaptive linearizing control of bioreactors

Ferreira, E. C.; Azevedo, S. Feyo de

In this communication we shall present developments concerning the synthesis of Single-Input, Single-Output (SISO) and Multi-Input, Multi-Output (MIMO) adaptive linearizing algorithms for the operation of bioreactors. Results will be illustrated for the baker’s yeast fermentation process. The synthesis of these non-linear control laws is performed by employing differential geometry techniques with system linear...



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    Financiadores do RCAAP

Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia