We report on the friction and diffusion of a single mobile nano-colloidal disk, whose size and mass are one and two orders of magnitude, respectively, greater than the molecules of the host solvent; all particles are restricted to move in a two-dimensional space. Using molecular dynamics simulations, the variation of the transport coefficients as a function of the thermodynamic state of the supporting fluid, in particular, around those states in the neighbourhood of the liquid-liquid phase coexistence, is investigated. The diffusion coefficient is determined through the fit of the mean-square displacement at long times and with the Green-Kubo relationship for the velocity autocorrelation function, whereas the friction coefficient is computed from the correlation of the fluctuating force. From the determination of the transport properties, the applicability of the Stokes-Einstein relation in two dimensions around the second critical point is discussed.
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http://dx.doi.org/10.1039/c7cp08302e | DOI Listing |
Sci Rep
January 2025
Department of Mechanical Engineering, College of Engineering, University of Ha'il, 81451, Ha'il City, Saudi Arabia.
Non-Newtonian fluids are also widely used in a variety of scientific, engineering, and industrial domains, including the petroleum sector and polymer technologies. They are vital in the development of drag-reducing agents, damping and braking systems, food manufacturing, personal protective equipment, and the printing industry. Fluid movement and transport via porous materials draw a lot of attention; they are important in science and technology.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Enterprise Engineering "Mario Lucertini", University of Rome Tor Vergata, 00133 Rome, Italy.
Copper, though highly conductive, requires improved wear resistance and thermal dissipation in applications that involve continuous movement and current-induced vibrations, such as power breakers. Conventional solutions, such as copper-tungsten alloys or lubricant use, face limitations in durability, friction, or environmental impact. This study explores the development of copper-graphene (Cu-GNPs) composite coatings using pulsed electrodeposition to enhance the tribological, thermal, and mechanical properties of circuit breaker components by adopting an industrially scalable technique.
View Article and Find Full Text PDFChaos
December 2024
Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, Košice 042 00, Slovakia.
The generalized Langevin equation (GLE) for a tagged particle in a liquid of charged particles under the influence of external AC electric fields is studied. For the fractional memory kernel in the GLE, the mean square displacement (MSD) of the particle is studied analytically in both the underdamped and overdamped regimes. The MSD consists of a part corresponding to the absence of the external field and a part affected by the external field, which is expressed through the mean velocity of the particle.
View Article and Find Full Text PDFHeliyon
May 2024
Department of Mathematics, Vellore Institute of Technology, Vellore, 632014, India.
Magnetohydrodynamic (MHD) flows have several applications in a wide area of engineering such as industrialized processes, including generating MHD electrical power, processing of magnetic materials, etc. The present examination focuses on incorporating the induced magnetic field (IMF) and multiple slips on the convective MHD Casson nanofluid flow over an elongating sheet with Brownian motion and thermophoresis effects. Heat source/sink, non-linear radiation, and suction/injection impacts are added to strengthen the study.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Powder Technology and Advanced Materials, HEI-VS, HES-SO University of Applied Sciences and Arts Western Switzerland, Rue de l'Industrie, 23, 1950 Sion, Switzerland.
Biodegradable magnesium alloy medical implants have attracted considerable interest thanks to their remarkable biocompatibility and mechanical properties. However, the rapid corrosion rate of magnesium alloys in physiological environments presents a major challenge to their practical application. Therefore, this study attempted to design a silane/chitosan /graphene oxide composite coating that reduces the corrosion and enhances the biodegradation of magnesium alloys used in temporary implants.
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