In this work we present a formalism for the calculation of the local elastic constants in inhomogeneous systems based on a method of planes. Unlike previous work, this formalism does not require the partitioning of the system into a set of finite volumes over which average elastic constants are calculated. Results for the calculation of the local elastic constants of a nearest-neighbor Lennard-Jones fcc crystal in the bulk and in a thin film are presented. The local constants are calculated at exact planes of the (001) face of the crystal. The average elastic constants of the bulk system are also computed and are consistent with the local constants. Additionally we present the local stress profiles in the thin film when a small uniaxial strain is applied. The resulting stress profile compares favorably with the stress profile predicted via the local elastic constants. The surface melting of a model for argon for which experimental and simulation data are available is also studied within the framework of this formalism.
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http://dx.doi.org/10.1103/PhysRevE.67.031601 | DOI Listing |
Polymers (Basel)
January 2025
School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Republic of Korea.
Carbon nanomaterials, particularly carbon nanotubes (CNTs), are widely used as reinforcing fillers in rubber composites for advanced mechanical and electrical applications. However, the influence of rubber functionality and its interactions with CNTs remains underexplored. This study investigates electroactive elastomeric composites fabricated with CNTs in two common diene rubbers: natural rubber (NR) and acrylonitrile-butadiene rubber (NBR), each with distinct functionalities.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
For those piezoelectric materials that operate under high-power conditions, the piezoelectric and dielectric properties obtained under small signal conditions cannot be directly applied to high-power transducers. There are three mainstream high-power characterization methods: the constant voltage method, the constant current method, and the transient method. In this study, we developed and verified a combined impedance method that integrated the advantages of the constant voltage and current methods, along with an improved transient method, for high-power testing of PZT-5H piezoelectric ceramics.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, Tamka 12, 91-403 Lodz, Poland.
The aim of this research was to obtain two-layer polymer composites with favorable mechanical and functional properties. The composites consisted of one lower layer of polymer with less elastic properties, containing no admixtures, and one upper layer of polymer with more elastic properties, containing plant admixtures, in the amount of 10% by weight of either goldenrod ( L.), or of turmeric ( L.
View Article and Find Full Text PDFGels
January 2025
Institute for Polymers and Composites, University of Minho, 5800-048 Guimarães, Portugal.
A set of carrageenans produced in the potassium form and with chemical structures varying from pure iota-carrageenans to nearly pure kappa-carrageenans is submitted to ultrasonication to reduce their molecular masses Mw while maintaining a constant chemical structure and a polydispersity index around 2. The kinetics of ultrasound-induced chain scission are found to be slower for polysaccharides richer in kappa-carrageenan disaccharide units. From the elasticity of samples directly gelled in a rheometer at 1 /% in 0.
View Article and Find Full Text PDFSci Rep
January 2025
Applied Optics Laboratory, Institute of Optics and Precision Mechanics, University Setif 1, Setif, 19000, Algeria.
This prediction evaluates the different physical characteristics of magnetic materials XFeO (X = Mg, Ca and Sr) by using density functional theory (DFT). The generalized gradient approximation (GGA) approach is chosen to define the exchange and correlation potential. The structural study of the compounds XFeO (X = Mg, Ca and Sr) shows that the ferromagnetic phase is the more stable ground state, where all the parameters of the network are given at equilibrium.
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