A local defect resonance for linear and nonlinear ultrasonic thermography

An efficient wave-defect interaction is the key to a high thermal response of flaws in ultrasonic thermography. To selectively enhance defect vibrations a concept of local defect resonance is developed and applied to ultrasonic activation of defects. The frequency match between the defect resonance frequency and the probing ultrasonic wave results in a substantial rise of a local defect temperature. The defect resonance is accompanied by depletion of the excitation frequency vibration due to nonlinear frequency conversion to higher harmonics. The local generation of higher frequency components provides a high thermal defect response in such an acoustically nonlinear thermography mode

He-broadening and shift coefficients of water vapor lines in infrared spectral region

The water vapor line broadening and shift coefficients in the ν1+ν2, ν2+ν3, ν1+ν3, 2ν3, 2ν1, 2ν2+ν3, and ν1+2ν2 vibrational bands induced by helium pressure were measured using a Bruker IFS 125HR spectrometer. The vibrational bands 2ν3 and ν1+2ν2 were investigated for the first time. The interaction potential used in the calculations of broadening and shift coefficients was chosen as the sum of pair potentials, which were modeled by the Lennard-Jones (6-12) potentials. The vibrational and rotational contributions to this potential were obtained by use of the intermolecular potential parameters and intramolecular parameters of H2O molecule. The calculated values of the broadening and shift coefficients were compared with the experimental data. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Investigation of interaction of carbon dioxide with aerogels nanopores

The absorption spectrum of 2 0 0 12 – 0 0 0 01 band of carbon dioxide, confined in 20 nm nanopores of silica aerogel, was measured with help of a Bruker IFS 125 HR Fourier transform spectrometer at room temperature and a spectral resolution of 0.01 cm-1. The obtained dependence of spectral line half-width values on rotational quantum numbers was studied and compared with data available in the literature. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Parameters of broadening of water molecule absorption lines by argon derived using different line profile models

The water vapor absorption spectrum was measured in the spectral region 6700–7650 cm–1 with argon as a buffer gas. The room-temperature spectrum was measured using a Bruker IFS 125-HR Fourier Transform Spectrometer with high signal-to-noise ratio, with a spectral resolution of 0.01 cm–1, at argon pressures from 0 to 0.9 atm. The H2O absorption spectral line parameters are derived by fitting two line shape profiles (Voigt and speed-dependent Voigt) to the experimental spectrum. It is shown that the use of speed-dependent Voigt profile provides the best agreement with experimental data

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

The dynamics of quasi-isometric foliations

If the stable, center, and unstable foliations of a partially hyperbolic system are quasi-isometric, the system has Global Product Structure. This result also applies to Anosov systems and to other invariant splittings. If a partially hyperbolic system on a manifold with abelian fundamental group has quasi-isometric stable and unstable foliations, the center foliation is without holonomy. If, further, the system has Global Product Structure, then all center leaves are homeomorphic.Comment: 18 pages, 1 figur

Anticorrosive properties of epoxy coatings, impregnated with manganese-containing pigments

© Research India Publications 2015. Most inhibiting pigments, imparting high anticonosive properties to the primer modern metal materials, contain extremely oxidated chromium, and as a consequence, are toxic. Search for low-toxic pigments comparable on the effectiveness of the protective effect with chioiniuin-containing pigments remains today an urgent task. As a film-forming material, it was used the epoxy oligomer E-40 being widely applicable in the paint industry epoxy, for which, polyethylene polyamine served as a hardener. Calcining calcium manganite, manganite-co-precipitated calcium silicate, and manganese blue were chosen as anticonosive pigments, the properties of anticonosi\*e coating on the basis of epoxy oligomer E-40 pigmented with manganese compounds were investigated. It has been found that inclusion of the synthesized pigment into composition of coatings enhances their ability to inhibit undei’film corrosion of steel. It has been proposed compounds of anticonosive primers on the effectiveness of protective action, surpassing industrial counterparts. The paper investigates influence of the content and nature of manganese anticonosive pigments on the protective properties of epoxy coatings. It has been shown that in the region of pigmentation below the critical, there is an increase of auticonosion efficiency of coatings. It has been evaluated the critical volume content of pigment, developed the formulations of primers, coatings on the basis of which the effectiveness of corrosion exceed the industry analogue

Woe from stones: commemoration, identity politics and Estonia's 'War of Monuments'

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