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Analytical characterization of particle kinematics and transverse dispersion in free-flow acoustophoretic devices

The overdamped dynamics of particles dragged by a parallel flow in a straight micro-channel in the presence of a transverse acoustophoretic force is investigated. Analytical solutions are presented in the case of plug, shear, or Poiseuille flow velocity profile. Two regimes of particle dynamics are observed, namely an early regime dominated by the local stream-wise velocity and a later regime gove

Quantifying dispersion of finite-sized particles in deterministic lateral displacement microflow separators through Brenner's macrotransport paradigm

Deterministic lateral displacement provides a novel and efficient technique for sorting micrometer-sized particles based on particle size. It is grounded on the principle that the paths associated with particles of different diameters, entrained in flow streaming through a periodic lattice of obstacles, are characterized by different deflection angles with respect to the average direction of the c

Dispersion-induced mixing in simple flows : Evidence for new anomalous scaling laws in the mixing boundary layer beyond the Lèvêque theory

We investigate the mixing layer thickness, δ(ξ), along the streamwise coordinate ξ of a straight channel fed with alternating streams of segregated solutes. We show the occurence of convection-enhanced mixing regimes downsteram the channel: i) an early-mixing regime, δ(ξ) ∼ξ 1/3 resembling the classical Lèvêque scaling of the thermal boundary layer, ii) an intermediate anomalous regime δ(ξ)∼ξ 3/5,

Spectral characterization of mixing properties of annular MHD micromixers

We develop a quantitative analysis of mixing regimes in an annular MHD-driven micromixer recently proposed by Gleeson et al. as a prototype for biomolecular applications. The analysis is based on the spectral properties of the advection - diffusion operator, with specific focus on the dependence of the dominant eigenvalue - eigenfunction on the Peclet number and on the system geometry. A theoretic

Scaling of the density of state of the weighted Laplacian in the presence of fractal boundaries

Spectral properties of the weighted Laplace operator in the presence of fractal boundaries are numerically investigated for both Neumann and Dirichlet boundary conditions. This corresponds to the characterization of heat and mass transport in microchannels with irregular and rough surfaces induced by the microfabrication process. The axial velocity field with no-slip boundary conditions, represent

Steady-state performance of an infinitely fast reaction in a three-dimensional open Stokes flow

We investigate the steady-state performance of a single irreversible mixing-controlled reaction between segregated reactant streams entering the annular gap between coaxial cylinders that can rotate independently. The three-dimensional Stokes flow results from the superposition of a pressure-driven Poiseuille flow along the mixer axis, and a cross-sectional Couette flow generated by the steady rot

The bumpy road to exercising leadership : Fragmentations in meaning and practice

The present study focuses on a manager’s understanding of leadership and how this guides – or does not guide practice. The paper reports an empirical in-depth study of a middle manager in an international manufacturing company. We link our discussion to both – the mainstream leadership studies, which assume that managers have a solid type of leadership behavior, and authors with a meaning-oriented

A cluster randomized controlled trial of a client-centred, activities of daily living intervention for people with stroke : One year follow-up of caregivers

Objective: Compare caregiver burden, provision of informal care, participation in everyday occupations and life satisfaction of caregivers to people with stroke, who either had received a client-centred, activities of daily living intervention or usual activities of daily living interventions. Design: A multicentre cluster randomized controlled trial in which 16 rehabilitation units were randomly

Prognostic Determinants of Coronary Atherosclerosis in Stable Ischemic Heart Disease : Anatomy, Physiology, or Morphology?

Risk stratification in patients with stable ischemic heart disease is essential to guide treatment decisions. In this regard, whether coronary anatomy, physiology, or plaque morphology is the best determinant of prognosis (and driver an effective therapeutic risk reduction) remains one of the greatest ongoing debates in cardiology. In the present report, we review the evidence for each of these ch

A Swedish approach to the prevention of type 1 diabetes

Background: The autoimmune destruction of beta cells, resulting in clinical type 1 diabetes, may start early in life and last for several months or years. During this period of time, we have an opportunity to try to prevent or delay further beta-cell destruction and clinical onset of type 1 diabetes. Objectives: Ongoing prediction and prevention studies in Skåne, Sweden are described. Methods: Dur