An analysis is performed of the experimental temperature and pressure dependences of thermal conductivity for different granite samples, obtained using the absolute stationary approach at 273-523 K and 0.1-400 MPa. The power mode of the temperature dependence of thermal conductivity at a fixed pressure with pressure-dependent coefficients is established.
The results of experimental measurements of the temperature dependence of the
effective thermal conductivity of various granite samples obtained by the
absolute stationary method in the temperature and pressure ranges of 273-
523 K and 0.1-400 MPa, respectively, are analyzed. The power-law character
of the temperature dependence of the effective thermal conductivity for all
measured granite samples at atmospheric pressure is established. We have
shown that pressure significantly affects the power law of the temperature
dependence of the effective thermal conductivity of granite samples. A
low-parameter description of the temperature-pressure behavior of thermal
conductivity is proposed. A correlation is established between its
components.
We have studied the behavior of the effective thermal conductivity of rocks (as natural heterogeneous materials) for the pressure range 0.1-400 MPa (initial region) and the temperature range 273-523 K. We propose a low-parametric empirical equation with great accuracy describing the effective thermal conductivity dependence, and discuss the physical meaning of its parameters.
We present an approach for the realization of extreme off-Hugoniot states of matter in laser-driven shock experiments. The method is based on the application of impedance-mismatch effect in sandwich targets. In order to verify this model we have realized numerical simulations using the two-dimensional hydrocode multi in three-layer targets (gold-aluminum-gold) with laser intensities ∼ 10(14) W/cm(2) and obtained pressures ∼ 10 Mbar. Results show the possibility of obtaining high pressures with relatively small temperatures for a low-impedance material sandwiched between layers with high density material.
We present an experimental study of the dynamics of shocks generated by the interaction of a double-spot laser in different kinds of targets: simple aluminum foils and foam–aluminum layered targets. The experiment was performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiance of a few 1015 W/cm2. Shock breakouts for pure Al and for foam-Al targets have been recorded using time-resolved self-emission diagnostics. Experimental results have been compared with numerical simulations. The shocks originating from two spots move forward and expand radially in the targets, finally colliding in the intermediate region and producing a very strong increase in pressure. This is particularly clear for the case of foam layered targets, where we also observed a delay of shock breakout and a spatial redistribution of the pressure. The influence of the foam layer doped with high-Z (Au) nanoparticles on the shock dynamics was also studied.
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