A lattice Boltzmann (LB) scheme is described, which recovers the equations developed by Qian-Sheng for the hydrodynamics of a nematic liquid crystal with a tensor order parameter. The standard mesoscopic LB scalar density is generalized to a tensor quantity and the macroscopic momentum, density, and tensor order parameter are recovered from appropriate moments of this mesoscopic density. A single lattice Boltzmann equation is used with a direction dependent Bhatnagar, Gross, and Krook (BGK) collision term, with additional forcing terms to recover the antisymmetric terms in the stress tensor. A Chapman-Enskog analysis is presented, which demonstrates that the Qian-Sheng scheme is recovered, provided a lattice with sixth-order isotropy is used. The method is validated against analytical results for a number of cases including flow alignment of the order tensor and the Miesowicz viscosities in the presence of an aligning magnetic field. The algorithm accurately recovers the predicted changes in the order parameter in the presence of aligning flow, and magnetic, fields. Preliminary results are given for an extension of the method to model the interface between isotropic and nematic fluids.
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http://dx.doi.org/10.1103/PhysRevE.67.061703 | DOI Listing |
Science
January 2025
Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
Chirality, a pervasive form of symmetry, is intimately connected to the physical properties of solids, as well as the chemical and biological activity of molecular systems. However, inducing chirality in a nonchiral material is challenging because this requires that all mirrors and all roto-inversions be simultaneously broken. Here, we show that chirality of either handedness can be induced in the nonchiral piezoelectric material boron phosphate (BPO) by irradiation with terahertz pulses.
View Article and Find Full Text PDFJpn J Ophthalmol
January 2025
Department of Ophthalmology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
Purpose: Chemical chelation with ethylenediaminetetraacetic acid (EDTA) is an established treatment for calcific band keratopathy (CBK), whereas removal of calcium deposits from the subepithelial layer of the cornea may cause corneal irregularity. Using Fourier harmonic analysis, we analyzed the corneal topography in eyes with CBK treated by EDTA chelation.
Study Design: Retrospective, single-center study.
Environ Monit Assess
January 2025
Department of Botany, Bacha Khan University, Charsadda, Charsadda, 24420, Khyber Pakhtunkhwa, Pakistan.
Wastewater is commonly contaminated with many pharmaceutical pollutants, so an efficient purification method is required for their removal from wastewater. In this regard, an innovative tertiary Se/SnO@CMC/Fe-GA nanocomposite was synthesized through encapsulation of metal organic frameworks (Fe-glutaric acid) onto Se/SnO-embedded-sodium carboxy methyl cellulose matrix to thoroughly evaluate its effectiveness for adsorption of levofloxacin drug from wastewater. The prepared Se/SnO@CMC/Fe-GA nanocomposite was analyzed via UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) to valuate optical property, size, morphology, thermal stability, and chemical composition.
View Article and Find Full Text PDFBull Math Biol
January 2025
Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Woodstock Rd, Oxford, Oxfordshire, OX2 6GG, UK.
We analyse mathematical models of blood flow in two simple vascular networks in order to identify structural features that lead to the formation of multiple equilibria. Our models are based on existing rules for blood rheology and haematocrit splitting. By performing bifurcation analysis on these simple network flow models, we identify a link between the changing flow direction in key vessels and the existence of multiple equilibria.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE, Brazil.
In this study, we investigate the phase behavior and structural organization of colloidal particles in a two-dimensional (2D) system under isotropic harmonic confinement using overdamped Langevin dynamics simulations. We employ a modified mermaid potential, which introduces an additional short-distance term resulting in a null-force region, distinct from the conventional mermaid potential. This modification facilitates a richer exploration of self-assembled structures, revealing a variety of phases influenced by the interplay between confinement strength V0 and the interaction potential.
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