STABILITY AND AMBIGUOUS REPRESENTATION OF SHOCK WAVE DISCONTINUITY IN MEDIA WITH ARBITRARY THERMODYNAMIC PROPERTIES

2009 ◽  
Author(s):  
A. P. Likhachev ◽  
A. V. Konyukhov ◽  
V. E. Fortov ◽  
A. M. Oparin ◽  
S. I. Anisimov ◽  
...  
Keyword(s):  
Shock Wave ◽  
Thermodynamic Properties

Cell model for quantum fluids. III. Compressional waves in liquid hydrogen

1965 ◽  
Vol 18 (9) ◽  
pp. 1309
Author(s):  
R Chen ◽  
D Henderson ◽  
RD Reed
Keyword(s):  
Shock Wave ◽  
Thermodynamic Properties ◽  
Cell Model ◽  
Liquid Hydrogen ◽  
Quantum Fluids ◽  
Velocity Of Sound ◽  
Compressional Waves ◽  
Quantum Parameter

The velocity of sound is calculated for each of the isotopic forms of liquid hydrogen using the quantum cell model. The velocity of sound increases as the pressure increases and decreases as the temperature increases. Also the reduced velocity of sound decreases as the value of the quantum parameter, Λ*, increases. In addition, the thermodynamic properties of liquid hydrogen compressed by a shock wave are calculated.

scholarly journals Multi-phase equation of state for aluminum

2007 ◽  
Vol 25 (4) ◽  
pp. 567-584 ◽  
Author(s):  
I.V. Lomonosov
Keyword(s):  
Shock Wave ◽  
Phase Diagram ◽  
High Pressure ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Critical Point ◽  
Theoretical Calculations ◽  
Static Compression ◽  
Multi Phase ◽  
Solid Liquid

AbstractResults of theoretical calculations and experimental measurements of the equation of state (EOS) at extreme conditions are discussed and applied to aluminum. It is pointed out that the available high pressure and temperature information covers a broad range of the phase diagram, but only irregularly and, as a rule, is not thermodynamically complete; its generalization can be done only in the form of a thermodynamically complete EOS. A multi-phase EOS model is presented, accounting for solid, liquid, gas, and plasma states, as well as two-phase regions of melting and evaporation. The thermodynamic properties of aluminum and its phase diagram are calculated with the use of this model. Theoretical calculations of thermodynamic properties of the solid, liquid, and plasma phases, and of the critical point, are compared with results of static and dynamic experiments. The analysis deals with thermodynamic properties of solid aluminum at T = 0 and 298 K from different band-structure theories, static compression experiments in diamond anvil cells, and the information obtained in isentropic-compression and shock-wave experiments. Thermodynamic data in the liquid state, resulting from traditional thermophysical measurements, “exploding wire” experiments, and evaluations of the critical point are presented. Numerous shock-wave experiments for aluminum have been done to measure shock adiabats of crystal and porous samples, release isentropes, and sound speed in shocked metal. These data are analyzed in a self-consistent manner together with all other available data at high pressure.The model's results are shown for the principal shock adiabat, the high-pressure melting and evaporation regions and the critical point of aluminum. New experimental and theoretical data helped to improve the description of the high-pressure, high-temperature aluminum liquid. The present EOS describes with high accuracy and reliability the complete set of available information.

Models of Thermodynamic Properties of Prominences

1979 ◽  
Vol 44 ◽  
pp. 349-355
Author(s):  
R.W. Milkey
Keyword(s):  
Thermodynamic Properties ◽  
Mass Transport ◽  
Emission Spectrum ◽  
Thermodynamic Parameters ◽  
Working Group ◽  
Physical Processes ◽  
Theoretical Concepts ◽  
Group 3 ◽  
Observational Techniques

The focus of discussion in Working Group 3 was on the Thermodynamic Properties as determined spectroscopically, including the observational techniques and the theoretical modeling of physical processes responsible for the emission spectrum. Recent advances in observational techniques and theoretical concepts make this discussion particularly timely. It is wise to remember that the determination of thermodynamic parameters is not an end in itself and that these are interesting chiefly for what they can tell us about the energetics and mass transport in prominences.

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

Electron microscopy study of shock synthesis of silicides

1993 ◽  
Vol 51 ◽  
pp. 1162-1163
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Close Contact ◽  
Microscopy Study ◽  
High Energy ◽  
Electron Microscopy Study ◽  
Powder Materials ◽  
Porous Powder ◽  
Wave Effects ◽  
Wave Passage

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.

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