High pressure adsorption of HCI from gaseous mixture on artificial sorbent materials

High temperature adsorption of HCl was applied on simulated generator gas.The artificial sorption materials were based on CaO-Al2O3

Flow of non-Newtonian fluids in fixed and fluidised beds

An attempt has been made to reconcile and to critically analyze the voluminous literature available on the flow of rheologically complex fluids through unconsolidated fixed beds and fluidised beds. In particular, consideration is given to the prediction of macro-scale phenomena of flow regimes, pressure drop in fixed and fluidised beds, minimum fluidisation velocity, dispersion and liquid-solid mass transfer. Available scant results seem to suggest that flow patterns qualitatively similar to that observed for Newtonian fluids, can be expected for the flow of purely viscous non-Newtonian fluids. A Reynolds number based on the effective pore size and pore velocity is seen to be a convenient parameter for the delineation of these flow regimes. Out of the four approaches available, the generalisation of the capillary model, due to Comiti and Renaud (Chem. Engng. Sci. 44 (1989) 1539-1545), appears to be the best for the estimation of the pressure drop through fixed beds. This method requires the flow rate - pressure drop data for the flow of a Newtonian fluid, such as air or water, through the same bed to evaluate the two key parameters, namely, the tortuosity and the dynamic surface area. While this approach can accommodate non-spherical particle shape and the wall effects and encompasses all possible flow regimes, it is limited to the situations where the polymer-wall interactions are negligible. Similarly, based on a combination of the capillary and drag models, satisfactory expressions have been identified for the prediction of the minimum fluidising velocity and velocity-voidage behaviour of uniformly expanded fluidised beds for power-law liquids and beds of spherical particles. Little is known about the effect of particle shape and column walls on these parameters. Even less work has been reported on dispersion and liquid-solid mass transfer in packed and fluidised beds, and no theoretical or experimental results seem to be available on heat transfer in these systems. Therefore, the expressions for the prediction of Peclet and Sherwood numbers presented herein must be regarded as somewhat tentative at this stage. Finally, little definitive and quantitative information is available on the role of viscoelasticity and of the effects arising from polymer/wall interactions, polymer retention, etc

Terminal velocity of spherical particles falling through non-Newtonian suspensions

The terminal falling velocities of glass, steel, and lead spheres in shear-thinning suspensions of kaolin and titanium dioxide in water solutions of glycerol have been measured. Overall, 130 spherical particle – suspension combinations gave been tested giving a Reynolds number range of 0.001 < Retn < 452. The suitability of the correlations presented for the prediction of the drag coefficient of spheres falling through power-law and Herschel–Bulkley model fluids, has been evaluated by comparing their predictions with the above-mentioned experimental data

Uncertainty of Phone Voicing and its Impact on Speech Synthesis

While unit selection speech synthesis is not at the centre of research nowadays, it shows its strengths in deployments where fast fixes and tuning possibilities are required. The key part of this method is target and concatenation costs, usually consisting of features manually designed. When there is a flaw in a feature design, the selection may behave in an unexpected way, not necessarily causing a bad quality speech output. One of such features in our systems was the requirement on the match between expected and real units voicing. Due to the flexibility of the method, we were able to narrow the behaviour of the selection algorithm without worsening the quality of synthesised speech