Temporal Frequency Spread of Plane Wave Propagation through Moderate to Strong Turbulence

In this study, we derive new expressions for the atmospheric-brought on frequency unfold of plane waves propagating thru slight to strong turbulence in a horizontal direction based on the modified anisotropic non-Kolmogorov electricity spectrum as antagonistic to conventional Kolmogorov electricity spectrum. The energy regulation price varies from three to 4 instead of the traditional Kolmogorov power law price; the general amplitude price differs from the conventional Kolmogorov regular cost 0.033. these new expressions are based on slight to robust fluctuation vicinity and anisotropic non-Kolmogorov turbulence. The simulation results show that temporal frequency unfold will decrease even as the anisotropic component   2  is increasing

Polynomial amplitude versus azimuth inversion in horizontally transverse isotropic media, as tested on fractured coal seams in the Surat Basin

A new technique of amplitude versus azimuth (AVAZ) seismic inversion in horizontally transverse isotropic (HTI) media is presented. AVAZ is an effective method of characterising anisotropic variation within individual reflectors as well as characterising fractures. The compressional wave reflectivity equation in HTI media has been reformulated into a parabolic form that allows for fast and efficient inversion. The isotropic component of the azimuthal reflectivity has been separated precisely from the anisotropic component and the anisotropic component has been decoupled exactly into its constituent elliptic and anelliptic components. The exact isotropic, elliptic and anelliptic amplitude versus offset (AVO) gradient equations in HTI media are presented herein and the amount of error associated with previous approximations is also defined under the assumption of weak anisotropy. A method of calculating Thomsen’s weak anisotropy parameters using these AVO gradient terms is then outlined. Compared with the elliptic method, there is reduced error incorporated in the new AVAZ method and the error relationships of this method are compared with the Fourier method. Data from an open file 3D wide azimuth seismic survey in the Surat Basin were inverted to demonstrate the effectiveness of the techniques which are presented herein. Seismic amplitudes from six azimuthal stacks were extracted over two horizons and inverted around a well where full-wave sonic and density logs were acquired. For both horizons, the error between the inverted anisotropy parameters from seismic and the inverted anisotropy parameters from wire line logs were found to be less than 5% for both horizons.

Regional macroseismic field and intensity residuals of the August 24, 2016, Mw=6.0 central Italy earthquake

A macroseismic investigation of the August 24, 2016, Mw=6.0 Central Italy earthquake, was carried out through an online web survey. Data were collected through a macroseismic questionnaire available at the website www.haisentitoilterremoto.it, managed by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). Over 12000 questionnaires were compiled soon after the seismic occurrence, coming from over 2600 municipalities. A statistical analysis was applied to the data collected in order to investigate the spatial distribution of intensity of the earthquake. The macroseismic intensity field (I) was described by identifying three main components: an isotropic component (II), a regional anisotropic component (IA) and a local random variations parameter (). The anisotropic component highlighted specific and well-defined geographical areas of amplification and attenuation. In general, the area between the Adriatic coast and Apennines Chain was characterized by an amplification of intensity, while the West side of the Apennines showed attenuation, in agreement with the domains found by other works focused on the analysis of instrumental data. Moreover, the regional macroseismic field showed similarities with instrumental PGA data. The results of our analysis confirm the reliability of web questionnaire data.

Studies on the Instrumental Factors Determining Errors in the Measurements of Raman Band Profiles. Part I: Optical Factors—A Comparison of Three Different Methods

A treatment is proposed which takes into account the following error sources in Raman band shape measurements: incident beam polarization, polarization analyzer misorientation, monochromator response, and observation over a finite solid angle. Three methods generally adopted for this type of measurements are compared in terms of the amount of spurious anisotropic component which enters the isotropic profile. The pertinence zones of each method are shown. The percentage of error is expressed by well-defined quantities entering analytical equations; this allows the experimentalist to choose the more suitable method on the basis of the experimental setup.

Collision-induced absorption in the fundamental band of nitrogen gas

Compressed nitrogen gas absorbs weakly in the vicinity of its vibrational fundamental frequency (ωvib = 2330 cm−1), with an intensity proportional to the square of the density. This absorption arises through vibrational modulation of the quadrupole-induced collisional dipole moment of a pair of N2 molecules. By neglecting the small anisotropy in the N2 intermolecular potential, we represent the spectral profile as the convolution of a single-molecule vibration–rotation band with a two-molecule translational component. Information theory is used to estimate the "least biased" form for the latter, based on our knowledge of its first four nonvanishing spectral moments. Our theory contains no adjustable parameters, yet yields results in good agreement with experiment. Our analysis shows that the anisotropic component of the molecular polarizability makes a fairly substantial contribution, about 12%, to the spectral intensity.