Encontrados 4 documentos, a visualizar página 1 de 1
Optimal sizing, scheduling and shift policy of the grinding section of a cerami...
Duarte, Belmiro P. M.; Santos, Lino O.; Mariano, Jorge S.This paper addresses the optimal design of the grinding section of a ceramic tile plant operating in a cyclic mode with the units (mills) following a batch sequence. The optimal design problem of this single product plant is formulated with a fixed time horizon of one week, corresponding to one cycle of production, and using a discrete-time resource task network (RTN) process representation. The size of the ind...
Moving finite elements method applied to dynamic population balance equations
Duarte, Belmiro P. M.; Baptista, Cristina M. S. G.A moving finite elements scheme is developed and used for solving 1-D dynamic population balance equations (PBE). The method stands on the weighted finite-elements based approach, and the local solutions are represented by cubic Hermite polynomials. The weighting function is the gradient of residuals with respect to time derivatives of the solution at the nodes and nodal velocities. The general PBE considered i...
Quality prediction in pulp bleaching: application of a neuro-fuzzy system
Paiva, Rui Pedro; Dourado, António; Duarte, BelmiroIn chemical industries, as paper pulp, quality control is a decisive task for competitiveness. Bleaching is a determinant operation in the quality of white pulp for paper. Quality prediction is decisive in quality control. However, the complexity of the bleaching process (and in general of industrial processes), its nonlinear and time-varying characteristics does not allow to develop reliable prediction models ...
Control charts: a cost-optimization approach for processes with random shifts
Zempléni, András; Véber, Miklós; Duarte, Belmiro; Saraiva, PedroIn this paper we describe an approach for establishing control limits and sampling times which derives from economic performance criteria and a model for random shifts. The total cost related to both production and control is calculated, based on cost estimates for false alarms, for not identifying a true out of control situation, and for obtaining a data record through sampling. We describe the complete proces...
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