A model is developed for prediction and interpretation of the observed steady-state axial dissolved oxygen concentration profiles in tall bubble columns. The observed concentration profiles are non-linear, unlike what would be expected if the hydrostatic pressure alone influenced the profiles. The non-linear profiles result from the axial mixing of liquid in the column. Several other factors in...

OBJECTIVES/HYPOTHESIS This investigation quantitatively characterizes the collagenous microstructure of human vocal ligament specimens excised postmortem from nonsmokers and smokers. STUDY DESIGN Retrospective cohort study. METHODS Second harmonic generation (SHG) imaging was performed at three anatomical locations of vocal ligament specimens: anterior, mid-membranous, and posterior regions...

In this paper, we examine the movement of particles within a continuous powder mixer using PEPT (Positron Emission Particle Tracking). The benefit of the approach is that the particle movement along the vessel can be measured non-invasively. The effect of impeller rotation rate, powder flow rate, and powder cohesion on the particle trajectory, dispersive axial transport coefficient, and residen...

[1] We provide a physically based explanation for the complex macroscopic behavior of dispersion in porous media as a function of Peclet number, Pe, using a pore-scale network model that accurately predicts the experimental dependence of the longitudinal dispersion coefficient, DL, on Pe. The asymptotic dispersion coefficient is only reached after the solute has traveled through a large number ...

Recently, an exact Eulerian-Lagrangian theory of advective transport in spacetime random velocity fields was developed by one of us. We present a formal extension of this theory that accounts for anisotropic local dispersion. The resultant (conditional) mean transport equation is generally nonlocal in space-time. To assess the impact of local dispersion on the prediction of transport under unce...

Introduction Dispersion is a phenomenon that determines the resolution of several types of liquid phase chromatography, and is an important component of overall transport through electrokinetic flow systems. The severe dispersion of solute as it travels through a U-turn, for example, has attracted recent attention for this reason [1]. In “ideal” electroosmotic flow through uniform, straight cha...

This paper concerns the Taylor-Aris dispersion of a dilute solute concentration immersed in a highly heterogeneous fluid flow having possibly sharp interfaces (discontinuities) in the diffusion coefficient and flow velocity. The focus is two-fold: (i) Calculation of the longitudinal effective dispersion coefficient, and (ii) sample path analysis of the underlying stochastic process governing th...