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The previous laboratory study of joint electrical resistivity and acoustic velocity measurements is reviewed for both consolidated and unconsolidated permafrost in this paper. The relation of logarithm of resistivity log(R) and P-wave velocity Vp is a concave function. An increase of temperature, fine content, and salinity results in a decrease of both acoustic velocity and electrical resistivity. Electrical resistivity is sensitive to salinity, while acoustic velocity changes substantially near thawing temperature. The joint measurement results could be used to estimate unfrozen water saturation (UWS) based on Archie's law, weighted equation (WE), or Kuster-Toksoz equations (KT). However, the estimated UWS from different methods is not always consistent. The difference can be up to 20%. It might be due to the fact that UWS is not the only parameter influencing the electrical and acoustic properties. In order to obtain consistent UWS, a joint model that combines the electrical effective medium theory (EMT) and the acoustic self-consistent approximation (SCA) is proposed. In this method, UWS and aspect ratio which describes particles shape are found simultaneously from the joint SCA-EMT model. Most of the results from the proposed method are between that of Archie's law and WE method, which indicates that the electrical method might overestimate UWS and acoustic method might underestimate it. [ABSTRACT FROM AUTHOR]

Bulk hyperbolic metamaterial properties in the THz regime in deep-subwavelength photonic crystals comprised of polar materials are discussed. The metamaterial behaviour of these systems is put under stringent tests revealing clear effective medium fingerprints. Electromagnetic (EM) in-coupling in such structures exhibits an exotic polarization sensitive profile that is controlled by the angle of the impinging wave and is characteristic of the existence of the hyperbolic type of dispersion. Also, these structures show a high figure of merit (FOM) for the extraordinary hyperbolic mode, which suggests that they are well-suited material for beam manipulation and steering. As a result, these polaritonic PC paradigms suggest a strong applications potential as optical set-up components at THz frequencies. [ABSTRACT FROM PUBLISHER]

Silver-doped As33S>67 and As33S33Se33 bulk glasses studied by means of Scanning Electron Microscopy (SEM) and infrared reflectivity, exhibit two-phase glasses, for a wide range of Ag concentration. Using the Effective Medium Approximation we show that the structure is actually a proper average of two components, a Ag-poor and a Ag-rich glass phase. The dominant structural unit in both phases is the pyramidal units AsX3/2 units. The latter are arranged in different medium-range order motifs. A detailed analysis of the reflectivity and absorption coefficient spectra made it possible to elucidate the short— and medium—range structural order for the Ag-poor and Ag-rich phases. [ABSTRACT FROM AUTHOR]