It is well known that there is an analogy between optics and mechanics that prompted much of the classical theory of mechanics and indeed extended it to the theory of quantum mechanics. We develop here an optical mechanical analogy for a prototypical nonholonomic mechanical system, a knife edge moving on a plane under the influence of a potential. We show that this approach is related to but different from the classical theory of Hamiltonization of nonholonomic systems.
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http://dx.doi.org/10.1103/PhysRevE.88.013204 | DOI Listing |
Small
January 2025
Department of Polymer Materials and Engineering, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300401, P. R. China.
Nowadays, much attention is paid to the development of high-performance and multifunctional materials, but it is still a great challenge to obtain polymer materials with high mechanical properties, high self-healing properties, and multifunctionality in one. Herein, an innovative strategy is proposed to obtain a satisfactory waterborne polyurethane (PMWPU-Bx) by in situ anchoring 3-aminophenylboronic acid (3-APBA) in a pyrene-capped waterborne polyurethane (PMWPU) via supramolecular interactions. The multiple functional sites inherent in 3-APBA can produce supramolecular interactions with groups on PMWPU, promoting the aggregation of hard domains in the polymer network, which confers the PMWPU-Bx strength (7.
View Article and Find Full Text PDFNanophotonics
January 2025
Instituto de Micro y Nanotecnología IMN-CNM, CSIC, CEI UAM+CSIC, Tres Cantos, Spain.
Acoustoplasmonic resonators, such as nanobars and crosses, are efficient acousto-optical transducers. The excitation of mechanical modes in these structures strongly depends on the spatial profile of the eigenmodes of the resonator. Using a system of two identical gold elongated bars placed on a silicon dioxide substrate, we examine how breaking mirror symmetries affects the optical and acoustic properties to provide insights in the design of acoustoplasmonic metasurfaces for nonsymmetric acousto-optical transducers.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2025
Department of Orthopaedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical Universit, Guangzhou, China.
Objective: The aim of this study is to assess the kinematic changes in the knee joint during walking in patients with isolated PCL-deficiency (PCLD) to determine the presence of walking-related joint instability (mechanical instability-abnormal displacement form structural damage). Additionally, the study seeks to provide biomechanical insights into the observed differences between subjective and objective assessments.
Methods: 35 healthy volunteers and 27 patients with isolated PCLD (both involved and uninvolved sides) were included in the study.
Heliyon
January 2025
Department of Petroleum Engineering, Omidiyeh Branch, Islamic Azad University, Omidiyeh, Iran.
Purpose: Biodiesel is a non-toxic, renewable, and environmentally friendly fuel used in compression ignition engines. This work aimed to develop FeO/SiO as a cheap, magnetic, and easy separable catalyst for biodiesel production from waste oil by sono-catalytic transesterification.
Methods: Fe₃O₄-SiO₂ was prepared using a modified Stober method and used as a heterogeneous catalyst in an ultrasound-assisted transesterification reaction to produce biodiesel.
ACS Appl Mater Interfaces
January 2025
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing 100730, China.
Multiple ocular surface disorders are associated with the mechanical properties of the interface between the eyelid and cornea. Determining eyelid pressure is vital for diagnosing and preventing these disorders. However, current measurements rely on flat piezoresistive pressure sensor arrays that lack eye-motion sensing capabilities, resulting in discomfort and measurement inaccuracies.
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