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Taylor dispersion--shear-induced enhancement of translational diffusion--is an important phenomenon with applications ranging from pharmacology to geology. Through experiments and simulations, we show that rotational diffusion is also enhanced for anisotropic particles in oscillatory shear. This enhancement arises from variations in the particle's rotation (Jeffery orbit) and depends on the strain amplitude, rate, and particle aspect ratio in a manner that is distinct from the translational diffusion. This separate tunability of translational and rotational diffusion opens the door to new techniques for controlling positions and orientations of suspended anisotropic colloids.
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http://dx.doi.org/10.1103/PhysRevLett.110.228301 | DOI Listing |
Eur Phys J E Soft Matter
September 2025
Université Gustave Eiffel, ENPC, Institut Polytechnique de Paris, CNRS, Navier, 77454, Marne-la-Vallée, France.
We experimentally study the heterogeneity of strain in a granular medium subjected to oscillatory shear in a rotating drum. Two complementary methods are used. The first method relies on optical imaging and grain tracking, allowing us to compute some components of the strain tensor and their variance.
View Article and Find Full Text PDFACS Omega
August 2025
Laboratory of Physico-Chemistry of Materials (LR01ES19), Faculty of Sciences, University of Monastir, Avenue of the Environment, Monastir 5019, Tunisia.
The study investigates the structural and dynamical properties of acetonitrile-water mixtures using molecular dynamics simulations over a broad range of acetonitrile molar fractions (0.0 to 1.0) and temperatures (298-348 K).
View Article and Find Full Text PDFJ Chem Phys
September 2025
Department of Physics, Stockholm University, 10691 Stockholm, Sweden.
The water molecule's electronic Cartesian multipole moment and polarizability tensors have been fitted with Gaussian process regression to the internal coordinates and are used to evaluate accurate electrostatic, induction, and dispersion energy components between flexible molecules. The model yields a handful of damping and scaling parameters that were adjusted for the energy components to agree with 2-body symmetry-adapted perturbation theory decomposition and then fine-tuned in order for the total energy to agree with CCSD(T) for small clusters. We present a simple algorithm for rotating symmetric Cartesian tensors and employ a dispersion potential based on multipole polarizabilities.
View Article and Find Full Text PDFNMR Biomed
October 2025
Neuroscience Research Australia (NeuRA), Sydney, Australia.
Measurements of muscle architecture are crucial for understanding muscle function but are often difficult to obtain in human muscles in vivo. This study aimed to create population-averaged atlases of human rotator cuff muscle shape and muscle fibre orientations from anatomical magnetic resonance images (MRI) and diffusion-weighted images (DWI) and to utilise these atlases to predict muscle fibre orientations from anatomical MRI data alone. An image registration framework was applied to coregister anatomical MRI and DWI data of 11 male and 9 female subjects into sex-specific common spaces, forming the basis for the atlases.
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2025
School of Astronautics, Beihang University, Beijing 100191, China.
Accurately characterizing the three-dimensional rotational dynamics of anisotropic nanoparticles remains challenging due to the limitations of both experimental techniques and conventional simulation methods, which often fail to capture the intricate details of rotational motion. We propose a small-angle approximation method to decouple the nanoparticle rotational dynamics about each of its three principal axes, while simultaneously resolving decoupled angular displacements. Validation through rotational autocorrelation functions and scaling analyses confirms that the proposed method accurately captures rotational diffusion coefficients for both nanorods and nanosheets in unentangled polymer melts.
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