Revista Jurídica Digital UANDES
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Tracking time-dependent production in electrokinetic Y-microreactors
No full textWe perform a theoretical study on the transient reaction-diffusion kinetics in an electrokinetic Y-shaped microreactor. The flow is assumed to be both steady and fully developed. The governing equations are solved in dimensionless form utilizing a 3D finite-volume based numerical algorithm, assuming a second-order irreversible reaction between the components. Analytical solutions are also obtained for cross-stream diffusion without reaction under a uniform velocity distribution. It is shown that the well-known butterfly-shaped form of the production concentration profile is not immediately created and it is established only after the system is sufficiently close to its steady-state. Furthermore, the inclination of the concentration peak toward the component of lower diffusivity or inlet concentration is less significant at the earlier stages of the production. Finally, it is demonstrated that the short-term influence of the parameters affecting the advection of mass on the total efficiency, defined as the ratio of the total production to the amount of the limiting reactant within the device, is quite the opposite of that at the steady-state. That is, whereas increasing each of the dimensionless Debye-Hückel parameter, the pressure-driven velocity to electroosmotic velocity ratio, and the Péclet number leads to larger short-term efficiencies, the opposite is true at the steady-state
Discussion of "Optimal treatment allocations in space and time for on-line control of an emerging infectious disease" by Laber, N. J. Meyer, B. J. Reich, K. Pacifici, J. A. Collazo and J. Drake
No full textAdjusting for Measurement Error in Retrospectively Reported Work Histories:An Analysis Using Swedish Register Data
No full textWe use work histories retrospectively reported and matched to register data from the Swedish unemployment office to assess: 1) the prevalence of measurement error in reported spells of unemployment; 2) the impact of using such spells as the response variable of an exponential model; and 3) strategies for the adjustment of the measurement error. Due to the omission or misclassification of spells in work histories we cannot carry out typical adjustments for memory failures based on multiplicative models. Instead we suggest an adjustment method based on a mixture Bayesian model capable of differentiating between misdated spells and those for which the observed and true durations are unrelated. This adjustment is applied in two manners, one assuming access to a validation subsample and another relying on a strong prior for the mixture mechanism. Both solutions demonstrate a substantial reduction in the vast biases observed in the regression coefficients of the exponential model when survey data is used
CFD-PBM simulation of turbulent drop break-up in a high-pressure static mixer
No full textThis work investigates the simulation of dilute, low-viscosity emulsions in a pilot-scale ACIP2 Sonolator using Computational Fluid Dynamics (CFD) and Population Balance Methods (PBM). Comparisons between the simulations and the experimental work of Ryan [1] show excellent agreement of the pressure drop (ΔP) and reasonable agreement of the Sauter mean diameter (d32). The effect of increasing oil viscosity in the d32 − ΔP correlation is also correctly captured. The numerical and the theoretical d32 − ΔP correlations are found to differ strongly with the experimental findings. The assumption of droplet break-up in the turbulent inertial regime (inherent to both theory and to current-state breakage frequency models) is found not to apply in the regions of intense break-up
