Statistical analysis of self-similar behaviour in the shear induced melting model

The analysis of the system behavior under the effect of the additive noises has been done using a simple model of shear melting. The situation with low intensity of the order parameter noise has been investigated in detail, and time dependence of the order parameter has been calculated. A distinctive feature of the obtained dependence is power-law distribution and self-similarity. The generalized Hurst exponent of the time series has been found within multifractal detrended fluctuation analysis. It is shown that the self-similarity of the time series increases when the noise intensity reduces.Comment: 11 pages, 9 figures, 29 reference

Formation of adsorbate structures induced by external electric field in plasma-condensate systems

We present a new model of plasma-condensate system, by taking into account an anisotropy of transference reactions of adatoms between neighbor layers of multi-layer system, caused by the strength of the electric field near substrate. We discuss an influence of the strength of the electric field onto first-order phase transitions and conditions for adsorbate patterning in plasma-condensate systems. It is shown that separated pyramidal-like multi-layer adsorbate islands can be formed in the plasma-condensate system if the strength of the electric field near substrate becomes larger tan the critical value, which depends on the interaction energy of adsorbate and adsorption coefficient.Comment: 8 pages, 8 figure

Stick-slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

This article presents an investigation of the dynamical contact between two atomically flat surfaces separated by an ultrathin lubricant film. Using a thermodynamic approach we describe the second-order phase transition between two structural states of the lubricant which leads to the stick–slip mode of boundary friction. An analytical description and numerical simulation with radial distributions of the order parameter, stress and strain were performed to investigate the spatial inhomogeneity. It is shown that in the case when the driving device is connected to the upper part of the friction block through an elastic spring, the frequency of the melting/solidification phase transitions increases with time

DYNAMICAL MODEL OF THE ASYMMETRIC ACTUATOR OF DIRECTIONAL MOTION BASED ON POWER-LAW GRADED MATERIALS

We consider an actuator whose driving bodies are made of Power-Law graded materials. The directional motion is generated by an asymmetric mechanism producing simultaneously vertical and horizontal oscillations of the indenter. The dynamic contact of gradient materials is described and the equation of motion for the drive is written down and analyzed. It is shown that the exponent of the elastic inhomogeneity significantly affects the average velocity of motion of the cargo, which can be dragged by the drive

Bending Rigidity of Two-Dimensional Titanium Carbide (MXene) Nanoribbons: A Molecular Dynamics Study

The interest in nanodiamond applications in biology and medicine is on the rise over recent years. This is due to the unique combination of properties that nanodiamond provides. Small size (~5 nm), low cost, scalable production, negligible toxicity, chemical inertness of diamond core and rich chemistry of nanodiamond surface, as well as bright and robust fluorescence resistant to photobleaching are the distinct parameters that render nanodiamond superior to any other nanomaterial when it comes to biomedical applications. The most exciting recent results have been related to the use of nanodiamonds for drug delivery and diagnostics—two components of a quickly growing area of biomedical research dubbed theranostics. However, nanodiamond offers much more in addition: it can be used to produce biodegradable bone surgery devices, tissue engineering scaffolds, kill drug resistant microbes, help us to fight viruses, and deliver genetic material into cell nucleus. All these exciting opportunities require an in-depth understanding of nanodiamond. This review covers the recent progress as well as general trends in biomedical applications of nanodiamond, and underlines the importance of purification, characterization, and rational modification of this nanomaterial when designing nanodiamond based theranostic platforms

Molecular Dynamic Study of the Mechanical Properties of Two-Dimensional Titanium Carbides Tiₙ₊₁Cₙ (MXenes)

Two-dimensional materials beyond graphene are attracting much attention. Recently discovered 2D carbides and nitrides (MXenes) have shown very attractive electrical and electrochemical properties, but their mechanical properties have not been characterized yet. There are neither experimental measurements reported in the literature nor predictions of strength or fracture modes for single-layer MXenes. The mechanical properties of two-dimensional titanium carbides were investigated in this study using classical molecular dynamics. Young\u27s modulus was calculated from the linear part of strain-stress curves obtained under tensile deformation of the samples. Strain-rate effects were observed for all Tin+1Cn samples. From the radial distribution function, it is found that the structure of the simulated samples is preserved during the deformation process. Calculated values of the elastic constants are in good agreement with published DFT data

Stick-slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

This article presents an investigation of the dynamical contact between two atomically flat surfaces separated by an ultrathin lubricant film. Using a thermodynamic approach we describe the second-order phase transition between two structural states of the lubricant which leads to the stick–slip mode of boundary friction. An analytical description and numerical simulation with radial distributions of the order parameter, stress and strain were performed to investigate the spatial inhomogeneity. It is shown that in the case when the driving device is connected to the upper part of the friction block through an elastic spring, the frequency of the melting/solidification phase transitions increases with time

Dynamical model of asymmetric actuator of directional motion

We consider an oscillation-based actuator in which directed motion is generated by a spherical contact subjected to superimposed oscillations in vertical and horizontal directions. We consider the full dynamical problem with account of contact forces arising due to the superimposed periodic loading. We find that the system can have two regimes: either motion in one direction or stick–slip motion, when velocity periodically changes its sign. The actuator can also produce directed motion against an external horizontal force (modeling dragging a “cargo”)