A depth-averaged model for non-isothermal thin-film rimming flow

A model for non-isothermal shear-driven thin-film flow on the inside surface of a stationary circular cylinder is presented. Motivated by an application to film flow in an aero-engine bearing chamber the model extends lubrication theory analysis of thin films to retain the important effects of inertia and heat convection.The accuracy of the depth-averaged temperature model is tested and comparisons illustrate the model is accurate for both conduction- and convection-dominant flows although local inaccuracies are introduced in regions exhibiting sharp changes in boundary temperature when convective effects are strong.Three rimming-flow configurations are considered: uni-directional flow with slowly-varying film height, a solution containing a steep front termed a shock, and a pooling solution where fluid accumulates in a recirculation at the base of the cylinder. The temperature field in the latter two which include recirculation features are greatly influenced by the strength of convection in the film

Fabrication and Optical Modeling of Micro‐Porous Membranes Index‐Matched with Water for On‐Line Sensing Applications

Membranes made of perfluorinated materials having a refractive index close to that of water enable straightforward detection of water solutes at the interface, hence providing a novel sensing tool for fluidic systems. Here it is reported the production by non-solvent induced phase separation and characterization of microporous membranes made of Hyflon AD, an amorphous copolymer of tetrafluoroethylene. Their optical turbidity when soaked in liquids having different refractive indices is studied and the data are interpreted with an optical model linking scattered light and structural features of the membrane. The average polymer and pore chord lengths obtained in this way scale with the filtering pore size measured by capil-lary flow porometry. Then, the optical response of the membranes when soaked in aqueous surfactant solutions is investigated and the effects of the molecular adsorption on the internal membrane surface is success-fully interpreted by an extension of the model. Overall, the results show that index-matched membranes can be designed and produced to provide a simple optical detection of the composition of the soaking liquid or to monitor the initial stage of membrane fouling

The Future of Cardiovascular Computed Tomography Advanced Analytics and Clinical Insights

Cardiovascular computed tomography (CCT) has undergone rapid maturation over the last decade and is now of proven clinical utility in the diagnosis and management of coronary artery disease, in guiding structural heart disease intervention, and in the diagnosis and treatment of congenital heart disease. The next decade will undoubtedly witness further advances in hardware and advanced analytics that will potentially see an increasingly core role for CCT at the center of clinical cardiovascular practice. In coronary artery disease assessment this may be via improved hemodynamic adjudication, and shear stress analysis using computational flow dynamics, more accurate and robust plaque characterization with spectral or photon- counting CT, or advanced quantification of CT data via artificial intelligence, machine learning, and radiomics. In structural heart disease, CCT is already pivotal to procedural planning with adjudication of gradients before and following intervention, whereas in congenital heart disease CCT is already used to support clinical decision making from neonates to adults, often with minimal radiation dose. In both these areas the role of computational flow dynamics, advanced tissue printing, and image modelling has the potential to revolutionize the way these complex conditions are managed, and CCT is likely to become an increasingly critical enabler across the whole advancing field of cardiovascular medicine. (c) 2019 by the American College of Cardiology Foundation.Cardiolog

Computed tomographic angiography in coronary artery disease.

Coronary computed tomographic angiography (CCTA) is becoming the first-line investigation for establishing the presence of coronary artery disease and, with fractional flow reserve (FFR <sub>CT</sub> ), its haemodynamic significance. In patients without significant epicardial obstruction, its role is either to rule out atherosclerosis or to detect subclinical plaque that should be monitored for plaque progression/regression following prevention therapy and provide risk classification. Ischaemic non-obstructive coronary arteries are also expected to be assessed by non-invasive imaging, including CCTA. In patients with significant epicardial obstruction, CCTA can assist in planning revascularisation by determining the disease complexity, vessel size, lesion length and tissue composition of the atherosclerotic plaque, as well as the best fluoroscopic viewing angle; it may also help in selecting adjunctive percutaneous devices (e.g., rotational atherectomy) and in determining the best landing zone for stents or bypass grafts