Encontrados 8 documentos, a visualizar página 1 de 1
Superhydrophobic surfaces produced using natural silica-based structures with p...
Oliveira, Nuno M.; Reis, R. L.; Mano, J. F.Publicado em "Journal of Tissue Engineering and Regenerative Medicine", vol. 17, supp. 1 (2013) ; Superhydrophobic surfaces (SHS) are characterized for exhibit extreme water repellency. Where water droplets roll easily and have a contact angle higher than 150º. The inspiration to produce artificial SHS comes from nature, the Lotus leaf. Hierarchical surface topographies at micro/nanoscale are critical for this...
Effect of guar gum on the physicochemical, thermal, rheological and textural pr...
Oliveira, Nuno M.; Dourado, Fernando Q.; Peres, António M.; Silva, Marta V.; Maia, João M.; Teixeira, José A.In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar...
Two-dimensional open microfluidic devices by tuning the wettability on patterne...
Oliveira, Nuno M.; Neto, Ana I.; Song, Wenlong; Mano, J. F.We present a simple and economical method to produce a potential open microfluidic polymeric device. Biomimetic superhydrophobic surfaces were prepared on polystyrene using a phase separation methodology. Patterned two-dimensional channels were imprinted on the superhydrophobic substrates by exposing the surface to plasma or UV–ozone radiation. The wettability of the channels could be precisely controlled betwe...
A robust strategy for optimizing complex distillation columns
Neves, Filipe J. M.; Silva, Dulce C. M.; Oliveira, Nuno M. C.This work introduces a strategy for the optimal design of distillation systems based on continuous optimization. The approach is similar to the one proposed earlier by [Lang, Y. -D., & Biegler, L. T. (2002). A distributed stream method for tray optimization. AIChE Journal, 48, 582], avoiding the need of solving extremely large and non-linear discrete optimization problems. When used with complex distillation un...
Continuous adiabatic industrial benzene nitration with mixed acid at a pilot pl...
Quadros, Paulo A.; Oliveira, Nuno M. C.; Baptista, Cristina M. S. G.A pilot plant for the continuous adiabatic nitration of benzene was constructed, reproducing the industrial operating conditions, in order to identify the reaction regime prevailing in this industrial process. Important process parameters were tested covering a wide range of operating conditions: reaction temperature (80-135 °C), benzene to nitric acid molar feed ratio (0.96-1.15) and stirring speed (390-1700 r...
Benzene nitration: validation of heterogeneous reaction models
Quadros, Paulo A.; Oliveira, Nuno M. C.; Baptista, Cristina M. S. G.The film and the Danckwerts penetration models were used to model the heterogeneous liquid-liquid reaction of benzene nitration. Analytical solutions were developed for both models considering a pseudo-first order reaction. Models were confronted with experimental results showing good predictions in the intermediate reaction regime (0.3<Ha<2). Profiles of both models were evaluated confirming similarities and i...
Optimization and nonlinear Model Predictive Control of batch polymerization sys...
Silva, Dulce C. M.; Oliveira, Nuno M. C.This paper addresses the optimization of batch polymerization systems, using a feasible path approach, with roots on Model Predictive Control (MPC) theory. The approach allows the reuse of many concepts previously developed for nonlinear MPC of continuous plants. It also provides an efficient and well-integrated methodology for the optimal supervision of discontinuous chemical processes. The application of this...
On-line implementation of nonlinear MPC: an experimental case study
Santos, Lino O.; Afonso, Paulo A. F. N. A.; Castro, José A. A. M.; Oliveira, Nuno M. C.; Biegler, Lorenz T.A nonlinear model predictive control algorithm is implemented on-line to control the liquid level and temperature in a pilot plant CSTR, where an irreversible exothermic chemical reaction is simulated experimentally by steam injection. The dynamic behavior of the pilot plant reactor is represented using a mechanistic, first principle model and a comparison between off-line simulation and experimental data is pr...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||