Method for computing the strain distribution near a wedge-like twin by using macroscopic dislocation model approaches

We develop a method for calculating the strain distribution near a wedge-like twin with various shapes of the boundaries. The method is based on the use of such a scale level at which one can assume that the distance between the twinning dislocations is infinitely small. We show that the twin boundary bending results in the loss of symmetry in the strain distribution of a wedge-like twin.     

Magnetoplastic effect upon twinning of bismuth single crystals

The effect of the magnetic field on the twinning of bismuth single crystals is studied. It is shown that a 1 T magnetic field contributes to an about twofold increase in the length and number of twins that appear near an external–stress concentrator.     

Potential Surface Waves in a Warm Nonisothermal Plasma Bounded by Metal

The dispersion properties of potential surface waves (SW), propagating at a warm nonisothermal plasma-metal boundary across the external magnetic field are studied in this paper. The existence of potential SW is shown to be possible in frequency ranges, where electromagnetic SW do not exist. The influence of transverse plasma density inhomogeneity on dispersion properties of the SW considered is studied as well.     

Heating self-interaction mechanism of surface magnetoplasma waves in plasma-like medium bounded by metal

The influence of electron heating in the high-frequency surface magnetoplasma wave(SM) field on dispersion properties of the considered SM is investigated. High frequency SM propagate at the interface between a plasma like medium with a finite electrons pressure and a metal. The nonlinear dispersion relation for the SM is derived and investigated.     

Subsonic jet noise suppression by a corrugated nozzle

We demonstrate the possibility of lowering the noise level of a subsonic jet using a crimped form of nozzle. The noise reduction is on the order of 2 dB.     

Graphene-Based Technologies for Tackling COVID-19 and Future Pandemics

The COVID-19 pandemic highlighted the need for rapid tools and technologies to combat highly infectious viruses. The excellent electrical, mechanical and other functional properties of graphene and graphene-like 2D materials (2DM) can be utilized to develop novel and innovative devices to tackle COVID-19 and future pandemics. Here, the authors outline how graphene and other 2DM-based technologies can be used for the detection, protection, and continuous monitoring of infectious diseases including COVID-19. The authors highlight the potential of 2DM-based biosensors in rapid testing and tracing of viruses to enable isolation of infected patients, and stop the spread of viruses. The possibilities of graphene-based wearable devices are discussed for continuous monitoring of COVID-19 symptoms. The authors also provide an overview of the personal protective equipment, and potential filtration mechanisms to separate, destroy or degrade highly infectious viruses, and the potential of graphene and other 2DM to increase their efficiency, and enhance functional and mechanical properties. Graphene and other 2DM could not only play a vital role for tackling the ongoing COVID-19 pandemic but also provide technology platforms and tools for the protection, detection and monitoring of future viral diseases.     

Method for the calculation of the stress fields for a wedge-shaped twin located at the surface of a crystal in the approximation of a continuous distribution of twinning dislocations along twin boundaries

A method is proposed to calculate the stress fields for a wedge-shaped twin located at the crystal surface. A graphic representation of the configuration of the fields of normal and cleavage stresses of a wedge-shaped twin has been obtained. It has been found that the stresses are localized not only at the twin boundaries and at its apex, but also in certain regions distant from the boundaries.     

State of stress at a crystal surface deformed by a concentrated load in the presence of a wedge twin

A procedure for the calculation of the stress fields near a wedge twin located at a crystal surface is developed using a dislocation macroscopic model. The problem is solved for the case of a concentrated load applied to the surface of a crystal with a twin. The concentrated load is found to increase the level of stresses near the wedge twin and to cause their localization at the twin boundary that is closer to the load application point.     

Dielectrophoretic deformation of breast cancer cells for lab on a chip applications

This paper presents the development and experimental analysis of a curved microelectrode platform for the DEP deformation of breast cancer cells (MDA‐MB‐231). The platform is composed of arrays of curved DEP microelectrodes which are patterned onto a glass slide and samples containing MDA‐MB‐231 cells are pipetted onto the platform's surface. Finite element method is utilised to characterise the electric field gradient and DEP field. The performance of the system is assessed with MDA‐MB‐231 cells in a low conductivity 1% DMEM suspending medium. We applied sinusoidal wave AC potential at peak to peak voltages of 2, 5, and 10 V_pp at both 10 kHz and 50 MHz. We observed cell blebbing and cell shrinkage and analyzed the percentage of shrinkage of the cells. The experiments demonstrated higher percentage of cell shrinkage when cells are exposed to higher frequency and peak to peak voltage electric field.     

The effect of the nonparabolicity of the free carriers dispersion law on the propagation of surface polaritons in a semiconductor-metal structure

The results of a study on the influence of the nonparabolicity of the free carriers dispersion law on the propagation of surface polaritons (SPs) located near the interface between an n-type semiconductor and a metal arc reported. The semiconductor plasma is assumed to be warm and nonisothermal. The nonparabolicity of the electron dispersion law has two effects. The first one is associated with nonlinear self-interaction of the SPs. The nonlinear dispersion equation and the nonlinear Schrodinger equation for the amplitude of the SP envelope are obtained. The nonlinear evolution of the SP is studied on the base of the above mentioned equations. The second effect results in third harmonics generation. Analysis shows that these third harmonics may appear as a pure surface polariton, a pseudosurface polariton, or a superposition of a volume wave and a SP depending on the wave frequency, electron density and lattice dielectric constant.