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A new adaptive controller based on a neural network was constructed and applied to turbulent channel flow for drag reduction. A simple control network, which employs blowing and suction at the wall based only on the wall-shear stresses in the spanwise direction, was shown to reduce the skin friction by as much as 20% in direct numerical simulations of a(More)
This paper presents the application of a neural network controller to the problem of active drag reduction in a fully turbulent 3D fluid flow regime. The neural network learns a function nearly identical to an analytically derived control law. We then demonstrate the ability of a neural controller to maintain a drag-reduced flow in a fully turbulent fluid(More)
Web-based programming exercises are a useful way for students to practice and master essential concepts and techniques presented in introductory programming courses. Although these systems are used fairly widely, we have a limited understanding of how students use these systems, and what can be learned from the data collected by these systems. In this(More)
Most catheter-based vascular medical devices today have hydrophilic lubricious coatings. This study was designed to perform a territory-based downstream analysis of end organs subsequent to angioplasty with coated balloon catheters to better understand the potential in vivo physiological consequence of coating wear materials. Coronary angioplasty was(More)
This article reports on the concept of a fibrinolytic surface based on the preferential adsorption of endogenous plasminogen from blood. Data are presented indicating that such a surface, when pretreated with tissue-type plasminogen activator (tPA), is able to dissolve nascent thrombus generated in contact with flowing whole blood. Polyethylene (PE)(More)
Using graphics in introductory programming assignments has been shown to be a useful way to reinforce concepts and engage students. However, the complexity of modern GUI frameworks means that students must be shielded from the underlying complexity of those frameworks, usually through substantial wrapper APIs or project skeletons. In this paper, we describe(More)
Studies on the interactions of tissue plasminogen activator (tPA) and plasminogen with polyurethane surfaces containing epsilon-lysine moieties (epsilon-amino group free) are reported. These surfaces are considered to have the potential to dissolve nascent clots that may be formed on them. For adsorption from both single protein solutions and plasma, the(More)
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