K. Yu. Osipov

Interrelation between electromagnetic response parameters and impact excitation characteristics in insulators

The effect of the impact energy and duration on the parameters of the electromagnetic response from concrete is studied. These two parameters are shown to affect the spectral characteristics of the response. The duration of the first pulse of the response reflects the duration of the impact excitation active stage. An impact excitation energy above 5×10−2 J causes irreversible residual strains in concrete.

Evaluating the depth of open cracks in concrete from parameters of electric response to elastic-impact excitation

We have studied the character of decay of the spectral components of electric response to elastic impact excitation of a concrete sample with artificial cracks of various depths. A criterion for determining the depth of surface cracks in concrete is proposed based on results of time-frequency analysis of the response signal.

Peculiarities of the mechanoelectrical response in dielectric materials in the region of structural phase transformations

The influence of thermally induced structural phase transformations on the electromagnetic response of gypsum upon impact excitation is investigated. It is found that the electromagnetic response upon impact excitation is the structure-sensitive characteristics of dielectric materials. Data on the character of phase transformations in gypsum heated above 150°C are obtained using X-ray diffraction techniques.

Numerical modeling of SF6 photoacoustic gas analyzer in the atmosphere with frequency modulation of thermal radiation

A simple design of a photoacoustic gas analyzer with a thermal source and an interference filter is suggested. The photoacoustic gas analyzer operation was modeled in the LabView visual programming environment while measuring the sulfur hexafluoride (SF6) concentration in atmospheric air. The optimal parameters of its elements were determined, i.e., a photoacoustic cell, an interference filter, an infrared thermal source, and microphones. The influence of the main absorbing components of the air on the PA signal amplitude was considered. It is shown that the use of low-cost commercial elements of the gas analyzer allows detection of atmospheric SF6 to a threshold level of about 0.06 ppm.

Interrelation between the stressed state in composites and the parameters of the electromagnetic response to a mechanical impulse

The effect of the stressed state due to mechanical and temperature fields on the parameters of electromagnetic emission is studied with model specimens consisting of a cement-sand binder and a metallic inclusion. The evolution of the electromagnetic response to a pulsed mechanical excitation is shown to depend on the arrangement of inclusions with respect to the direction of the applied load. A mechanism of mechanoelectrical transformations in stressed composites is proposed.

Design and modeling of a photoacoustic gas analyzer with a thermal source for carbon isotope ratio analysis

A diagram is suggested and numerical simulation is carried out of a photoacoustic gas analyzer with a thermal source and first order interference filter for carbon isotope ratio analysis. An optimal spectral range for gas analyzer operation is selected. In the wavelength range selected, the spectral parameters of the atmosphere are analyzed, as well as of some gases, which, being present in samples under study, could affect the measurement results. The gas analyzer suggested allows us to measure the carbon isotope ratio 13C/12C in CO2 samples with a minimal error of about 0.5‰, and could be useful for detection of such gases as SO2, CO, and NH3, absorption lines of which fall in the selected spectral range.

A method for determining the depth of concrete surface fractures by electric response to elastic impact excitation

Studies of the transformation and attenuation of spectral components of electric responses to the elastic impact excitation of a concrete sample with artificial fractures of different depths are carried out. A generalized criterion for determining the depth of open fractures in concrete is proposed based on the analysis of results using the correlation and time-frequency analysis.

Improving the accuracy of the mechanoelectric method for determining the strength of concrete

A technique for nondestructive testing of concrete strength according to parameters of an electric response to an elastic impact excitation was developed on the basis of experimental investigations. The technique allows the testing of concrete with a high surface roughness, including conditions under which concrete is exposed to external electromagnetic noise.

Modification of the experimental setup of the FTIR spectrometer and thirty-meter optical cell for measurements of weak selective and nonselective absorptions

The improvement of the experimental setup based on a Fourier spectrometer Bruker IFS-125 and a 30-meter multipass optical cell is described. The improvement includes the cell equipment with a system of automated adjustment of the number of beam passes without cell depressurization and ensures the cell work at high temperatures.

Influence of pulsed infrared illumination on the speed of human perception of optical information

The influence of subthreshold pulsed infrared illumination on the recognition reaction time was investigated when recognizing geometric figures on a monitor screen.