We use Heisenberg's approximation to derive analytic expressions for eddy viscosity and eddy diffusivity from the transfer integrals of energy and mean-square scalar arising from the Navier-Stokes and passive scalar dynamics. In the same scheme, we evaluate the flux integrals for the transports of energy and mean-square scalar. These procedures allow for the evaluation of relevant amplitude ratios, from which we calculate the universal numbers, namely, Batchelor constant B, Kolmogorov constant C, and turbulent Prandtl number σ, under two different schemes (with and without ε expansion). Our results are comparable with existing theoretical, numerical, and experimental values. As a byproduct, we obtain a relation between C, B, and σ, namely, B=σ C. To compare our results with the experimental values, we calculate Batchelor constant in one dimension (B'). Within the same framework, we also see that with increasing values of space dimension d, the Prandtl number σ increases and approaches unity, while the Kolmogorov constant C and Batchelor constant B approach very close to each other. For large space dimensions, we find the asymptotic B=B(0)d(1/3), and evaluate B(0).
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http://dx.doi.org/10.1103/PhysRevE.84.036315 | DOI Listing |
Biomacromolecules
January 2025
Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia.
The environmental concerns about petroleum-based polymers drive the search for sustainable alternatives. This paper investigates sustainable cellulose nanocrystal (CNC) films for packaging applications. CNC films are transparent and provide an excellent barrier against oxygen with moderate performance against water vapor.
View Article and Find Full Text PDFMed Sci Sports Exerc
January 2025
Department of Kinesiology, University of Georgia, Athens, GA.
Purpose: This study measured the time course mV̇O 2 max following both maximal and submaximal exercise.
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Exp Eye Res
September 2024
Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA. Electronic address:
Previous studies have shown that pharmaceutical agents such as lipoic acid have the ability to soften the lens, presenting a promising avenue for treating presbyopia. One obstacle encountered in the preclinical stage of such agents is the need for precise measurements of lens elasticity in experimental models. This study aimed to evaluate the effects of 25-hydroxycholesterol, lipoic acid, and obeticholic acid on the viscoelastic properties of mouse lenses using a custom-built elastometer system.
View Article and Find Full Text PDFJ Synchrotron Radiat
May 2024
Karlsruhe Institute of Technology, Institute for Photon Science and Synchrotron Radaiation (IPS), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.
To characterize an electron beam, visible synchrotron light is often used and dedicated beamlines at synchrotron sources are becoming a more common feature as instruments and methods for the diagnostics are, along with the accelerators, further developed. At KARA (Karlsruhe Research Accelerator), such a beamline exists and is based on a typical infrared/visible-light configuration. From experience at such beamlines no significant radiation was expected (dose rates larger than 0.
View Article and Find Full Text PDFFront Psychol
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Connections: The Learning Sciences Platform, Quito, Ecuador.
Problem-solving skills are highly valued in modern society and are often touted as core elements of school mission statements, desirable traits for job applicants, and as some of the most complex thinking that the brain is capable of executing. While learning to problem-solve is a goal of education, and many strategies, methodologies, and activities exist to help teachers guide the development of these skills, there are few formal curriculum structures or broader frameworks that guide teachers toward the achievement of this educational objective. Problem-solving skills have been called "higher order cognitive functions" in cognitive neuroscience as they involve multiple complex networks in the brain, rely on constant rehearsal, and often take years to form.
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