Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.Comment: 5 pages, 2 figures, 1 tabl

The determination of the thermal properties of unconsolidated materials

Heat transfer in a composite cylindrical region is considered. An approximate analytical solution of the direct problem is obtained. It is shown that, beginning at the instant t > t , the relative error of the solution obtained does not exceed 1%. On the basis of this, algorithms are constructed which enable inverse problems to be solved effectively. Examples of the use of the algorithms to determine the thermal properties of unconsolidated materials are presented. © 2012 Springer Science+Business Media, Inc

Features of periodic temperature profiles in filtrating capillary porous media

The behavior of temperature profiles is examined in filtrating capillary porous media which are subjected to periodic heating. Reasons are described for amplitude shift in the temperature oscillations versus the fluid filtration rate. © 1992 Plenum Publishing Corporation

Freezing and melting of 3D complex plasma structures under microgravity conditions driven by neutral gas pressure manipulation

Freezing and melting of large three-dimensional complex plasmas under microgravity conditions is investigated. The neutral gas pressure is used as a control parameter to trigger the phase changes: Complex plasma freezes (melts) by decreasing (increasing) the pressure. Evolution of complex plasma structural properties upon pressure variation is studied. Theoretical estimates allow us to identify main factors responsible for the observed behavior.Comment: Phys. Rev. Lett. (in press); 4 pages, 4 figure

Fluid-solid phase transitions in 3D complex plasmas under microgravity conditions

Phase behavior of large three-dimensional complex plasma systems under microgravity conditions onboard the International Space Station is investigated. The neutral gas pressure is used as a control parameter to trigger phase changes. Detailed analysis of structural properties and evaluation of three different melting/freezing indicators reveal that complex plasmas can exhibit melting by increasing the gas pressure. Theoretical estimates of complex plasma parameters allow us to identify main factors responsible for the observed behavior. The location of phase states of the investigated systems on a relevant equilibrium phase diagram is estimated. Important differences between the melting process of 3D complex plasmas under microgravity conditions and that of flat 2D complex plasma crystals in ground based experiments are discussed.Comment: 13 pages, 10 figures; submitted to Phys. Rev.

Hardware and Software for Determining the Thermal Properties of Rocks Under Close to Stratified Conditions

An instrument for determining the nonlinear thermal properties of rocks under natural conditions is proposed. Software is developed for processing the temperature readings, obtained from the instrument sensors, using mainly the theory of the solution of inverse problems for a parabolic-type nonlinear equation. Practical examples of the determination of the nonlinear thermal properties of some materials are presented. © 2014 Springer Science+Business Media New York

A search for J^{PC}=1^{-+} exotic mesons in the pi- pi- pi+ and pi- pi0 pi0 systems

A partial wave analysis (PWA) of the pi-pi-pi+ and pi-pi0pi0 systems produced in the reaction pi- p -> (3pi)-p at 18 GeV/c was carried out using an isobar model assumption. This analysis is based on 3.0M pi-pi0pi0 events and 2.6M pi-pi-pi+ events and shows production of the a2(1320), pi2(1670) and \pi(1800) mesons. An earlier analysis of 250K pi-pi-pi+ events from the same experiment showed possible evidence for a J^{PC}=1^{-+}$ exotic meson with a mass of 1.6 GeV/c^2 decaying into rho pi. In this analysis of a higher statistics sample of the (3pi)- system in two charged modes we find no evidence of an exotic meson.Comment: 4 pages, 5 figures, added comment about the negative reflectivity exotic wave

Directions of perfection of development of bitumen deposits on the basis of geothermal modelling layers

In clause the opportunity of increase of efficiency of thermal influence on the bitumen layers, described is considered by a complex structure. Results of modelling of thermal influence on layers described are resulted by a complex structure. Results of modelling of thermal influence on layers with spreading water are resulted. The opportunity of optimization of system of development of a deposit on the basis of regulation of input of the heat-carrier and a grid of chinks with reference to concrete is considered