The present article establishes connections between the structure of the deterministic Navier-Stokes equations and the structure of (similarity) equations that govern self-similar solutions as expected values of certain naturally associated stochastic cascades. A principle result is that explosion criteria for the stochastic cascades involved in the probabilistic representations of solutions to the respective equations coincide. While the uniqueness problem itself remains unresolved, these connections provide interesting problems and possible methods for investigating symmetry breaking and the uniqueness problem for Navier-Stokes equations. In particular, new branching Markov chains, including a dilogarithmic branching random walk on the multiplicative group (0, ∞), naturally arise as a result of this investigation.
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http://dx.doi.org/10.1063/1.4913236 | DOI Listing |
Biomed Phys Eng Express
January 2025
Ingeniería y Tecnología, Universidad Nacional Autonoma de Mexico Facultad de Estudios Superiores Cuautitlan, Av. 1o de Mayo S/N, Santa María las Torres, Campo Uno, 54740 Cuautitlán Izcalli, Edo. de Méx., Cuautitlan Izcalli, Estado de México, 54740, MEXICO.
Hemodialysis is a crucial procedure for removing toxins and waste from the body when kidneys fail to perform this function effectively. This study addresses the need to improve the efficiency and biocompatibility of membranes used in dialyzers. We simulate fluid flow through two types of membranes, Cuprophan (cellulosic) and AN69ST (synthetic), to understand the complex mechanisms involved and quantify key variables such as pressure, concentration, and flow.
View Article and Find Full Text PDFBeijing Da Xue Xue Bao Yi Xue Ban
February 2025
Department of General Dentistry, Peking University School and Hospital of Stomatology & National Center for Stomato-logy & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China.
Objective: The triply periodic minimal surface (TPMS) Gyroid porous scaffolds were built with identical porosity while varying pore sizes were used by fluid mechanics finite element analysis (FEA) to simulate the microenvironment. The effects of scaffolds with different pore sizes on cell adhesion, proliferation, and osteogenic differentiation were evaluated through calculating fluid velocity, wall shear stress, and permeability in the scaffolds.
Methods: Three types of gyroid porous scaffolds, with pore sizes of 400, 600 and 800 μm, were established by nTopology software.
Entropy (Basel)
January 2025
Faculty of Civil Engineering, Architecture and Environmental Engineering, Lodz University of Technology, 90-924 Łódź, Poland.
The main aim of this study is to achieve the numerical solution for the Navier-Stokes equations for incompressible, non-turbulent, and subsonic fluid flows with some Gaussian physical uncertainties. The higher-order stochastic finite volume method (SFVM), implemented according to the iterative generalized stochastic perturbation technique and the Monte Carlo scheme, are engaged for this purpose. It is implemented with the aid of the polynomial bases for the pressure-velocity-temperature (PVT) solutions, for which the weighted least squares method (WLSM) algorithm is applicable.
View Article and Find Full Text PDFLangmuir
January 2025
School of Mechanical Engineering, Shenyang University of Technology, Shenyang 110870, China.
Microscale device surface encapsulation needs to use ultrafine liquid transfer technology. This technology can transfer a liquid from a donor surface to a receptor surface in a controlled manner. However, the requirement of microscale encapsulation for liquid transfer amounts is generally at the pL level.
View Article and Find Full Text PDFEur Heart J Cardiovasc Imaging
January 2025
School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
Aim: To establish an imaging-based method to quantify left ventricular (LV) diastolic pressures.
Methods/results: In 115 patients suspected of coronary artery disease, LV pressure was measured by micromanometers and images by echocardiography. LV filling pressure was measured as LV pre-atrial contraction pressure (pre-A PLV).
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