Photoacoustic effect in micro- and nanostructures: numerical simulations of Lagrange equations

The  work  provides  the  description  of  theoretical  and  numerical  modeling  techniques of thermomechanical effects that take place in absorbing micro- and nanostructures of different materials under the action of pulsed laser radiation. A proposed technique of the numerical simulation is based on the solution of equations of motion of continuous media in the form of Lagrange for spatially inhomogeneous media. This model allows calculating fields of temperature, pressure, density, and velocity of the medium depending on the parameters of laser pulses and the characteristics of micro- and nanostructures.The  work  provides  the  description  of  theoretical  and  numerical  modeling  techniques of thermomechanical effects that take place in absorbing micro- and nanostructures of different materials under the action of pulsed laser radiation. A proposed technique of the numerical simulation is based on the solution of equations of motion of continuous media in the form of Lagrange for spatially inhomogeneous media. This model allows calculating fields of temperature, pressure, density, and velocity of the medium depending on the parameters of laser pulses and the characteristics of micro- and nanostructures

Providence Independent, V. 8, Thursday, December 14, 1882, [Whole Number: 392]

[4] p. “Persistent in the Right – Fearless in Opposing Wrong.” Newspaper published in Trappe, Pa. Weekly. Contains local, national and international news, fiction and advertisements.https://digitalcommons.ursinus.edu/providence/1172/thumbnail.jp

Transverse Effects under Four-Wave Coupling in the Nonlinear Fabry–Perot Interferometer

Specific features of the light-beam transverse structure transformation in the process of four-wave coupling in the Fabry–Perot interferometer with a resonant nonlinearity under conditions of bifurcation of the symmetry breaking and optical bistability are analyzed. The asymmetric regimes of the interaction, characterized by a difference both in the integrated transmission functions of the nonlinear interferometer for two light beams with equal intensities and in the spatial intensity distribution at the exit of the interferometer, are considered

Multiwave Mixing of Singular Light Beams in Resonant Media

A method for transforming the topological structure of a singular light beam under multiwave mixing in the media with resonant nonlinearity is justified theoretically. The effect of self- and cross-modulation of the light waves under condition of nonlinear variation of the refractive index on stability of the optical vortices appearing in the multiwave mixing is studied

Wave front transformation of optical vortices with multiwave interactions in resonant media

The transformation of singular light beams is analyzed theoretically for multiwave interactions on amplitude and phase dynamic holograms in media with a resonant nonlinearity. The possibility of multiplying topological charge using different diffraction orders is demonstrated and optimal conditions for parametric energy exchange are determined which ensure retention of the structure of the wave front of optical vortices

Transformation of Optical Vortices by Polarization Dynamic Holograms

Results of theoretical and experimental studies of regularities in the transformation of the topological and polarization structures of optical vortices by polarization dynamic holograms formed by pulse Gaussian and singular light beams in dye solutions are presented

Photoacoustic effect in micro- and nanostructures: numerical simulations of Lagrange equations

The work provides the description of theoretical and numerical modeling techniques of thermomechanical effects that take place in absorbing micro- and nanostructures of different materials under the action of pulsed laser radiation. A proposed technique of the numerical simulation is based on the solution of equations of motion of continuous media in the form of Lagrange for spatially inhomogeneous media. This model allows calculating fields of temperature, pressure, density, and velocity of the medium depending on the parameters of laser pulses and the characteristics of micro- and nanostructures

Algorithm for a forecast assessment of negative changes in underground water in the territory of non centralized water supply

The water quality of non-centralized water supply sources largely depends on the presence of active karst processes. Underground waters of karst origin are a vulnerable component of the geological environment to the influence of modern anthropogenic factors that violate natural hydrogeological and geoecological conditions. One of the indicators of the development of karst processes is the level of river runoff and mineralization of underground wate

Vulnerability assessment of karst underground waters in the territory of non-centralized water supply

This paper considers an individual approach to assessing the vulnerability of karst groundwater. It is based on the allocation of such indicators as the geological structure of the observed territory, the concentration of runoff entering the karst channels, and the precipitation regime. Due to regional climatic, hydrogeological and landscape features, a private methodology for assessing the vulnerability of karst groundwater has been develope