ELECTRICAL CONDUCTIVITY OF INERT GASES—SEED COMBINATION IN SHOCK TUBES

1964 ◽  
Vol 42 (8) ◽  
pp. 1548-1563 ◽  
Author(s):  
J. Lau
Keyword(s):  
Shock Wave ◽  
Electrical Conductivity ◽  
Shock Waves ◽  
Alkali Metal ◽  
Shock Tube ◽  
Digital Computer ◽  
Theoretical Calculations ◽  
Inert Gases ◽  
Temperature Ratio ◽  
Seeding Material

The effect of seeding shock waves with alkali metal smoke is studied. The pressure, density, temperature ratio, electron density, and conductivity were calculated with a digital computer and tabulated for various combinations of gas and seeding material. A hydrogen-driven shock tube was constructed to measure the properties of the seeded gas behind the shock wave. The conductivity of argon seeded with cesium was measured with a conductivity probe and compared with theoretical calculations.

ELECTRICAL CONDUCTIVITY OF INERT GASES – SEED COMBINATION IN SHOCK TUBES: II. REFLECTED SHOCK MEASUREMENTS IN ARGON

1965 ◽  
Vol 43 (7) ◽  
pp. 1334-1341 ◽  
Author(s):  
J. Lau ◽  
E. Mills
Keyword(s):  
Electrical Conductivity ◽  
Shock Waves ◽  
Shock Tube ◽  
Cesium Chloride ◽  
Incident Shock ◽  
Inert Gases ◽  
Shock Tubes ◽  
End Plate ◽  
Reflected Shock

The electrical conductivity of argon behind reflected shock waves in a shock tube was measured and compared with theory. The effect of seeding the argon with cesium chloride smoke was studied. The shock tube and seeding apparatus used was described by Lau (1964), except for a section added ahead of the dump tank where a gate can slide to form the end plate where the incident shock is reflected.

scholarly journals On Fast Magnetic Field Reconnection

1976 ◽  
Vol 71 ◽  
pp. 353-366 ◽  
Author(s):  
E. R. Priest ◽  
A. M. Soward
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Electrical Conductivity ◽  
Shock Waves ◽  
Similarity Solutions ◽  
Diffusion Region ◽  
Magnetohydrodynamic Equations ◽  
Reconnection Rate ◽  
Mathematical Basis ◽  
Rate Dependent

The first model for ‘fast’ magnetic field reconnection at speeds comparable with the Alfvén speed was put forward by Petschek (1964). It involves one shock wave in each quadrant radiating from a central diffusion region and leads to a maximum reconnection rate dependent on the electrical conductivity but typically of order 10-1 or 10-2 of the Alfvén speed. Sonnerup (1970) and Yeh and Axford (1970) then looked for similarity solutions of the magnetohydrodynamic equations, valid at large distances from the diffusion region; by contrast with Petschek's analysis, their models have two waves in each quadrant and produce no sub-Alfvénic limit on the reconnection rate.Our approach has been, like Yeh and Axford, to look for solutions valid far from the diffusion region, but we allow only one wave in each quadrant, since the second is externally generated and so unphysical for astrophysical applications. The result is a model which qualitatively supports Petschek's picture; in fact it can be regarded as putting Petschek's model on a firm mathematical basis. The differences are that the shock waves are curved rather than straight and the maximum reconnection rate is typically a half of what Petschek gave. The paper is a summary of a much larger one (Soward and Priest, 1976).

Effects of Shock Waves on Acceleration of Cell Growth Rate by Shock Tube

2008 ◽  
Author(s):  
Masaaki Tamagawa ◽  
Norikazu Ishimatsu
Keyword(s):  
Shock Wave ◽  
Growth Rate ◽  
Endothelial Cells ◽  
Shock Waves ◽  
Shock Tube ◽  
Test Case ◽  
Plane Shock ◽  
Extracorporeal Shock Wave ◽  
Shock Wave Pressure

This paper describes effects of shock waves on cells to certificate the angiogenesis by shock wave (pressure wave) in the clinical application such as ESW (Extracorporeal Shock Wave). Especially, to investigate the effects of shock waves on the endothelial cells in vitro, the cells worked by plane shock waves using shock tube apparatus are observed and measured in the microscope. The peak pressure working on the endothelial cells at the test case is 0.4 MPa. After working shock waves on suspended cells, growth rate (area per one cell and population of cells) are measured by image processing. It is found that the growth rate of the shock-worked cells from 0 to 4h is clearly high compared with control one. It is concluded that once shock waves worked, the cells have capacity to increase growth rate in vitro. This preliminary result will be applied to fundamental investigations about shock wave stimulus on several kinds of cells in future.

SPECTROSCOPIC TEMPERATURE MEASUREMENTS IN A SHOCK TUBE USING CN AS A THERMOMETRIC MOLECULE

1960 ◽  
Vol 38 (6) ◽  
pp. 715-719 ◽  
Author(s):  
W. H. Parkinson ◽  
R. W. Nicholls
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Shock Tube ◽  
Wave Velocity ◽  
Dynamic Theory ◽  
Shock Wave Velocity ◽  
Velocity Measurements ◽  
Shock Excitation ◽  
Intensity Measurements ◽  
Gas Dynamic

Rotational intensity measurements on the CN spectrum, excited through shock excitation of a powdered mixture of NH4Cl, KNO2, and C by helium-driven shock waves in argon have been used to infer "rotational temperatures" of the gas between 6350 °K and 8750 °K. The measured values agree well with gas kinetic temperatures inferred from simple gas dynamic theory and shock-wave velocity measurements.

scholarly journals Interaction of Shock Waves with Discrete Gas Inhomogeneities: A Smoothed Particle Hydrodynamics Approach

2019 ◽  
Vol 9 (24) ◽  
pp. 5435 ◽  
Author(s):  
Andrea Albano ◽  
Alessio Alexiadis
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Shock Tube ◽  
Smoothed Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Interaction Of Shock Waves ◽  
Smoothed Particle ◽  
Different Shapes ◽  
The Difference

In this study, we propose a smoothed particle hydrodynamics model for simulating a shock wave interacting with cylindrical gas inhomogeneities inside a shock tube. When the gas inhomogeneity interacts with the shock wave, it assumes different shapes depending on the difference in densities between the gas inhomogeneity and the external gas. The model uses a piecewise smoothing length approach and is validated by comparing the results obtained with experimental and CFD data available in the literature. In all the cases considered, the evolution of the inhomogeneity is similar to the experimental shadowgraphs and is at least as accurate as the CFD results in terms of timescale and shape of the gas inhomogeneity.

BULK NANOSTRUCTURED MATERIALS OBTAINED BY SHOCK WAVES COMPACTION OF ULTRAFINE TITANIUM AND ALUMINUM

2012 ◽  
Vol 05 ◽  
pp. 391-399
Author(s):  
NIKOLOZ M. CHIKHRADZE ◽  
CONSTANTIN POLITIS ◽  
MIKHEIL CHIKHRADZE ◽  
GEORGE ONIASHVILI
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Theoretical Calculations ◽  
Steel Tube ◽  
Hydrodynamic Theory ◽  
Full Density ◽  
Experimental Investigations ◽  
Disperse Powder ◽  
Explosive Compaction ◽  
Structural Investigations

Theoretical and experimental Investigations of shock wave consolidation processes of Ti - Al nano sized and ultra-disperse powder compositions are discussed. For theoretical calculations of the shock wave loaded materials were used the hydrodynamic theory and experimental adiabatic of Ti and Al . The normal and tangential stresses in the cylindrical steel tube (containers of Ti - Al reaction mixtures) were estimated using the partial solutions of elasticity theory. The mixtures of ultra-disperse Ti and nano sized (≤ 50nm) Al powder compositions were consolidated to full or near-full density by explosive-compaction technology. The ammonium nitride based industrial explosives were used for generation of shock waves. To form ultra-fine grained bulk TiAl intermetallics with different compositions, ultra-disperse Ti particles were mixed with nano-crystalline Al . Each reaction mixture was placed in a sealed container and explosively compacted using a normal and cylindrical detonation set-up. Explosive compaction experiments were performed in range of pressure impulse (5-20) GPa. X-ray diffraction (XRD), structural investigations (SEM) and micro-hardness measurements were used to characterize the intermetallics phase composition and mechanical properties. The results of analysis revealing the effects of the compacting conditions and precursor particles sizes, affecting the consolidation and the properties of this new ultra high performance alloys are discussed.

Some Properties of Compressional Waves in Lennard-Jones and Devonshire Liquids. II. Shock Waves

1961 ◽  
Vol 14 (3) ◽  
pp. 372 ◽  
Author(s):  
HG David ◽  
SD Hamann
Keyword(s):  
Shock Wave ◽  
Equation Of State ◽  
Shock Waves ◽  
Qualitative Agreement ◽  
Theoretical Calculations ◽  
Condensed Substance ◽  
Adiabatic Expansion ◽  
Good Qualitative Agreement ◽  
Compressional Waves ◽  
Lennard Jones

This paper describes some theoretical calculations of the thermodynamic changes which occur when a condensed substance is compressed by a shock wave from an explosion. It is assumed that the material is a simple molecular fluid (or a plastic solid) obeying Lennard-Jones and Devonshire's equation of state. The calculations have been applied to single and colliding shock waves, to shocks generated in a precompressed material, and to the adiabatic expansion of a material from a shocked state. The results are in good qualitative agreement with the experi- mental data where these exist. In addition they suggest possible ways of extending the scope and usefulness of shock wave experiments.

Effects of Underwater Shock Wave on Endothelial Cells in Vitro Using Shock Tube

2007 ◽  
Author(s):  
Masaaki Tamagawa ◽  
Norikazu Ishimatsu
Keyword(s):  
Shock Wave ◽  
Growth Rate ◽  
Endothelial Cells ◽  
Shock Waves ◽  
Shock Tube ◽  
Shape Index ◽  
Plane Shock ◽  
Underwater Shock Wave ◽  
Extracorporeal Shock Wave

This paper describes effects of shock waves on cells to certificate the angiogenesis by shock wave (pressure wave) in the clinical application such as ESW (Extracorporeal Shock Wave). Especially, to investigate the effects of shock waves on the endothelial cells in vitro, the cells worked by plane shock waves using shock tube apparatus are observed by microscope. The peak pressure working on the endothelial cells at the test case is 0.4 MPa. After working shock waves on suspended cells, the disintegration, shape and growth rate (area per one cell and population of cells) are measured by image processing. It is found that the younger generation cells have small differences of shape index, and the growth rate of the shock-worked cells from 0 to 4h are clearly high compared with control ones. It is concluded that once shock waves worked, some of them are disintegrated, but the other has capacity to increase growth rate of cell culture in vitro. This preliminary result will be applied to fundamental investigations about shock wave stimulus on several kinds of cells in future.

scholarly journals Experimental investigation of shock waves in liquid helium I and II

1976 ◽  
Vol 75 (2) ◽  
pp. 373-383 ◽  
Author(s):  
John C. Cummings
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Shock Waves ◽  
Shock Tube ◽  
Liquid Helium ◽  
Initial Conditions ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Liquid Interface ◽  
Reflected Shock

The flow field produced by a shock wave reflecting from a helium gas-liquid interface was investigated using a cryogenic shock tube. Incident and reflected shock waves were observed in the gas; transmitted first- and second-sound shocks were observed in the liquid. Wave diagrams are constructed to compare the data with theoretical wave trajectories. Qualitative agreement between data and theory is shown. Quantitative differences between data and theory indicate a need for further analysis of both the gas-liquid interface and the propagation of nonlinear waves in liquid helium.This work was a first step in the experimental investigation of a complex non-equilibrium state. The results demonstrate clearly the usefulness of the cryogenic shock tube as a research tool. The well-controlled jump in temperature and pressure across the incident shock wave provides unique initial conditions for the study of dynamic phenomena in superfluid helium.

scholarly journals Development of Shock-Wave-Powered Actuators for High Speed Positioning (Second Report: Characteristics of Diaphragmless Shock Tube and Responsiveness of Actuator)

2013 ◽  
Vol 7 (5) ◽  
pp. 558-563
Author(s):  
Akira Kotani ◽  
◽  
Toshiharu Tanaka ◽  
Akira Hirano ◽  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Waves ◽  
Shock Tube ◽  
High Speed ◽  
Industrial Robots ◽  
Piston Motion ◽  
Diaphragmless Shock Tube ◽  
High Responsiveness ◽  
Piston Speed

Shock tubes experiments are conducted on applications of shock waves to the actuator. The high-pressure and low-pressure sections of a general shock tube are separated by a diaphragm. In this study, a shock wave is generated by “diaphragmless shock tube” which is divided into two sections by a driver piston instead of the diaphragm. We have previously reported on the motion of a driven piston powered by a shock wave. However, not only piston speed but also high responsiveness is required for practical actuators used on manufacturing lines, in industrial robots, etc., The diaphragmless shock tube constructed in this paper is structured to be able to examine not only the motion of the driven piston but also the motion of the driver piston. In addition, the responsiveness of the piston motion of the actuator powered by shock waves is examined. It follows from what has been said thus far that a shock wave can be applied to an actuator with high responsiveness.

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