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Vitrimers, an emerging class of polymer materials, are thermosets with dynamic covalent cross-linkers, allowing for topology rearrangement at elevated temperatures. However, vitrimers have several drawbacks, such as slow response times and often lack photothermal catalytic activity. Herein, we demonstrate that embedding functional nanofillers, i.e., hierarchically assembled plasmonic gold nanoparticles (AuNPs) on graphene nanoplatelets (GNPIs) into a vitrimer matrix, induces an ultrafast photothermal healing response. Unlike previous research that mainly focused on bulk materials, our exploration of vitrimer nanocomposite films uncovers unique advantages, such as optical transparency in the visible wavelength, flexibility, and ultrafast localized healing upon exposure to a 532 nm wavelength laser. These remarkable properties of vitrimer nanocomposite films were demonstrated with three various filler compositions and concentrations, where AuNPs/GNPls serve as a powerful filler. Photothermally activated self-healing of these hybrid materials is demonstrated by taking advantage of the localized surface plasmon resonance (LSPR) of AuNPs and the broad absorbance wavelength and high thermal conductivity of GNPls. Furthermore, profilometry is utilized to quantify the volume percent recovery of healing, providing quantitative evidence of increased healing with a higher filler concentration and laser dosage. This localized, ultrafast healing is pivotal for future coating applications, where bulk heating could lead to undesirable deformations. Our comprehensive understanding of the role of filler composition, filler concentration, and laser dosage in the self-healing properties of films opens up a wide array of potential applications for these light-responsive functional materials. The potential applications of these materials span from self-healing coatings to flexible electronics, inspiring a new era of innovative solutions. [ABSTRACT FROM AUTHOR]

Magnetic tweezers have emerged as a vital force spectroscopy tool for characterizing the mechanical properties of nucleic acids and their interactions with proteins. Harnessing the principles of magnetic theory, magnetic tweezers allow for the precise manipulation of biological compounds at the single-molecule level through the imposition of a magnetic field. This review focuses on the application of magnetic tweezers in the context of DNA studies, with a particular emphasis on the mechanical properties of DNA and its dynamic interactions with proteins and enzymes. These interactions are essential to genomic transactions such as DNA replication, repair, and transcription. Over the last few decades, magnetic tweezer technology has experienced significant advancements, leading to the development of different types of magnetic tweezers. These technological breakthroughs have opened up new avenues of scientific research, including studies related to DNA elasticity, supercoiling, replication, and repair. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the effects of steel-plate added damping and stiffness (ADAS) dampers, as a special kind of passive control device, on the seismic behavior of steel shear walls (SSWs). Various types of metallic dampers can be used to improve the seismic characteristics and hysteretic performance of the structures. However, ADAS dampers can increase ductility of the structures in addition to energy dissipating. This kind of damper is usually used for braced steel and concrete frames. In the present paper, ADAS dampers are added to a steel frame with steel shear wall and analyzed under cyclic loading. All of the investigations are carried out by using the finite element simulations in ABAQUS software which is verified by comparing with the experimental results. The results showed that by employing the added ADAS dampers in the frames with SSWs, it is possible to reduce the pinching phenomenon and enhance the damping capability of the structure which indicates their efficiency in system of steel shear walls under cyclic loadings. The obtained results showed that inserting the ADAS dampers into the frames equipped by SSWs can increase the equivalent viscos damping ratio from 3.317 to 4.08 (23%) and ductility from 6.55 to 9.92 (51.5%). [ABSTRACT FROM AUTHOR]

Abstract A scaling model is presented to analyze the nonlinear rheology of unentangled polymer melts filled with high concentration of small spherical particles. Assuming the majority of chains to be reversibly adsorbed to the surface of the particles, we show that the emergence of nonlinearity in the viscoelastic response of the composite system subjected to a 2D shear flow results from stretching of the adsorbed chains and increasing desorption rate of the adsorbed segments due to the imposed deformation. The steady-state shear viscosity of the mixture in nonlinear shear thinning regime follows the power law where is the applied shear rate. At large strain amplitude γ 0, the storage and loss moduli in strain sweep tests scale as and respectively.

The geometric nonlinear response of spherical shells made of sandwich functionally graded material (SFGM) under uniform external pressure incorporating the effects of transverse shear deformations is considered. The equilibrium and compatibility nonlinear differential equations can be solved by using the modified interaction method. All of the equations are developed based on the first-order shear deformation theory (FSDT). In the present study, the geometric nonlinear problem has been solved for special boundary conditions including movable and fixed clamped supports in the meridional direction. A closed-form nonlinear load-deflection relationship is developed for SFGM shell which expresses the equilibrium path of the shell. [ABSTRACT FROM AUTHOR]