Catalytic flow with a coupled Finite Difference -- Lattice Boltzmann scheme

Many catalyst devices employ flow through porous structures, which leads to a complex macroscopic mass and heat transport. To unravel the detailed dynamics of the reactive gas flow, we present an all-encompassing model, consisting of thermal lattice Boltzmann model by Kang et al., used to solve the heat and mass transport in the gas domain, coupled to a finite differences solver for the heat equation in the solid via thermal reactive boundary conditions for a consistent treatment of the reaction enthalpy. The chemical surface reactions are incorporated in a flexible fashion through flux boundary conditions at the gas-solid interface. We scrutinize the thermal FD-LBM by benchmarking the macroscopic transport in the gas domain as well as conservation of the enthalpy across the solid-gas interface. We exemplify the applicability of our model by simulating the reactive gas flow through a microporous material catalysing the so-called water-gas-shift reaction

Exact Analysis of TTL Cache Networks: The Case of Caching Policies driven by Stopping Times

TTL caching models have recently regained significant research interest, largely due to their ability to fit popular caching policies such as LRU. This paper advances the state-of-the-art analysis of TTL-based cache networks by developing two exact methods with orthogonal generality and computational complexity. The first method generalizes existing results for line networks under renewal requests to the broad class of caching policies whereby evictions are driven by stopping times. The obtained results are further generalized, using the second method, to feedforward networks with Markov arrival processes (MAP) requests. MAPs are particularly suitable for non-line networks because they are closed not only under superposition and splitting, as known, but also under input-output caching operations as proven herein for phase-type TTL distributions. The crucial benefit of the two closure properties is that they jointly enable the first exact analysis of feedforward networks of TTL caches in great generality

Thoughtful Integration of Active Learning Teaching Strategies into Physician Assistant Education

Introduction: The future of healthcare relies upon how we train student clinicians. It is integral to continually reevaluate our methodologies of teaching and work to better approach the challenging task of educating competent and compassionate physician assistants in a short two-to-three-year window. While the traditional modality of teaching has been primarily lecture-based, there has been a growing movement to incorporate active learning into medical education. This learner-driven model puts students in the driver’s seat and allows for greater amounts of self-directed learning prior to class followed by the reinforcement of concepts during class time. Though lecture-based teaching could be the approach of choice by the majority of medical programs due to perceived simplicity and ease, active learning is not as complicated as one may think and has the versatility to be integrated in a number of ways. Student engagement drives knowledge retention, and the more students are able to retain, the greater success they will have in clinical rotations and in their first years as clinicians. Currently, the literature supports active learning over conventional learning, but there are few articles describing how active learning can actually be implemented into medical education. The goal of this review is to reappraise the benefits of active learning and then describe ways to meaningfully integrate different forms of active learning into the physician assistant program didactic curriculum

Small-Signal Amplification of Period-Doubling Bifurcations in Smooth Iterated Maps

Various authors have shown that, near the onset of a period-doubling bifurcation, small perturbations in the control parameter may result in much larger disturbances in the response of the dynamical system. Such amplification of small signals can be measured by a gain defined as the magnitude of the disturbance in the response divided by the perturbation amplitude. In this paper, the perturbed response is studied using normal forms based on the most general assumptions of iterated maps. Such an analysis provides a theoretical footing for previous experimental and numerical observations, such as the failure of linear analysis and the saturation of the gain. Qualitative as well as quantitative features of the gain are exhibited using selected models of cardiac dynamics.Comment: 12 pages, 7 figure