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Precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor ope...

A meso oscillatory flow reactor (OFR) was successfully applied for the precipitation of hydroxyapatite (HAp) nanoparticles. Mixing efficiency of the mesoreactor operated batchwise in a vertical tube was evaluated at constant power density, by monitoring variation of hue values upon mixing both spatially and temporally. The best operating conditions for fast mixing and a more homogeneous reaction medium were ver...

Statistical tool combined with image analysis to characterize hydrodynamics and...

Image analysis technique has been proved to be very effective in the quantification of particles size and morphology distributions in different work areas. In the present work this technique was combined with the discriminant factorial analysis (DFA) in order to allow the automatic identification of single bubbles (isolated bubbles without influence of surrounded bubbles) in multiphase systems. With the previou...

Characterization of intermediate stages in the precipitation of hydroxyapatite ...

Precipitation of hydroxyapatite Ca 5(PO 4) 3OH (HAp) was carried out by mixing a saturated calcium hydroxide aqueous solution with an orthophosphoric acid aqueous solution at 37°C. In order to promote optimal conditions for the production of HAp with high yields, mixing of the reaction medium was assured by a novel metal stirrer. Different experimental conditions were studied varying the mixing Ca/P molar ratio...

Using an on-line image analysis technique to characterize sucrose crystal morph...

The morphological forms and habits of crystals and agglomeration are important properties on crystallization processes. Online techniques for realtime measurement of these properties are mandatory for a better comprehension of crystal growth phenomenon. The present paper presents and describes a new online method to determine the complexity level of a crystal or a population of crystals during a crystallization...

Effect of some solid properties on gas-liquid mass transfer in a bubble column

The knowledge about the effects of solids on gas–liquid systems and the respective physical mechanisms are not yet totally clarified. In this work, the effect of the solids on the mass transfer characteristics in a bubble column was studied experimentally for the systems air/water/expandable polystyrene (EPS) beads and air/water/glass beads. Volumetric liquid side mass transfer coefficient, kLa, was determined ...

Temperature and solid properties effects on gas–liquid mass transfer

The knowledge about the effect of solid phase properties, at different temperatures, on gas–liquid transfer and the respective physical mechanisms has been poorly studied. In the present work, the temperature and solid properties (size and density) effects on the gas–liquid mass transfer characteristics in a bubble column were experimentally evaluated. Gas–liquid–solid systems formed by air/water/polyvinyl chlo...

Kinetics and thermodynamics of sucrose crystallization from pure solution at di...

Growth rates of sucrose crystallization from pure solutions of initial relative supersaturation levels between 0.094 and 0.181 were studied in agitated crystallizer at 313.13 K. Birth and spread model was applicable for the obtained growth rate data in this range of supersaturation and used to estimate the principal growth parameters. The estimated interfacial free energy varied inversely with supersaturation f...

NovaFlow : novel applications of a state-of-the-art oscillatory flow platform :...

Application of a statistic tool for on-line characterization of bubble populati...

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/10968

Effect of solids on gas-liquid mass transfer

The effect of the solids on the mass transfer characteristics in a bubble column was studied experimentally for the systems air/water/Polyvinyl chloride (PVC) and air/water/glass beads. Volumetric liquid side mass transfer coefficient, kLa, was determined under different solid concentrations, gas flow rates and solid sizes. The presence of solids affects negatively kLa being this effect more pronounced for the ...