Electromagnetic particle velocity

Figure 3.9. Electromagnetic particle velocity profiles in limestone at 12 GPa. Profiles indicate both the arrival of the shock wave and the release wave from the free surface (Murri et al., 1975).

The vertical lines in the target represent cross-sections of the active elements of individual electromagnetic particle velocity gages ten gages are indicated... 

The experimental methods for the determination of the detonation wave parameters can be classified into two groups. The first, the so-called internal methods group, includes the methods by which detonation parameters are directly determined. These are the determination of the mass velocity of the detonation products by the electromagnetic particle velocity gauge method, direct determination of the detonation pressure by a manganin pressure gauge, determination of the mass velocity of the detonation products by the flash X-ray technique, etc. The time resolution of these methods can be on a nanoseconds scale, which is still not sufficient for fully reliable study of a very narrow chemical reactions zone, and in particular, of a shock wave front. 

Determination of the Detonation Parameters Using the Electromagnetic Particle Velocity Gauge Technique... 

Leiper, G.A., Kirby, I.J., and Hackett, A. Determination of Reaction Rates in Intermolecular Explosives Using the Electromagnetic Particle Velocity Gauge, Proc. 8th Symposium (International) on Detonation, NSWC MP 86-194, Albuquerque, NM, 1985, pp. 187-195. 

Mechanical wave-propagation problems are analyzed on the basis of quasistatic electromagnetic conditions. This is an excellent approximation since the electromagnetic wavespeed greatly exceeds the mechanical wavespeed and the particle velocity is typically only about one-tenth of the mechanical wavespeed. (See the discussion by Thurston [74T01].)... 

At present there are three basic techniques of measuring particle velocity, namely free surface velocity (FSV) measurements, electromagnetic velocity (EMV) measurements, and flash X-ray measurements. Before proceeding to describe these techniques, it should be noted that agreement among these techniques is not satisfactory. At present there is no consensus as to which technique is best , nor is there any real understanding as to why these different methods give different results... 

Aleksandrov et al (Ref 19) used an electromagnetic technique to get particle velocity (y) vs time profiles. They conclude that the breaks observed in such profiles coincide with the Chapman-Jouguet point, ie, the time of the break corresponds to the chem reaction time in a detonation. The reaction zone width, a, is then a = r (D — u)... 

Monitoring of solid/gas flow is important to safe and efficient operation of pneumatic transport that is used in many industrial processes such as coal mining and powder transport. Commonly employed techniques to measure particle velocity are a radioactive tracer method (Somerscales, 1981), optical techniques (Lee Srinivasan, 1978), electromagnetic methods (Bobis et al., 1986) and conventional mechanical approaches (Soo, 1990). 

In water n = 1.33, in plexiglass 1.5. j3-particles with energies > 0.6 MeV move faster than light in water. When the particle velocity (Vp) > c, electromagnetic radiation is... 

This frequency is a measure of the vibration rate of the electrons relative to the ions which are considered stationary. Eor tme plasma behavior, plasma frequency, COp, must exceed the particle-coUision rate, This plays a central role in the interactions of electromagnetic waves with plasmas. The frequencies of electron plasma waves depend on the plasma frequency and the thermal electron velocity. They propagate in plasmas because the presence of the plasma oscillation at any one point is communicated to nearby regions by the thermal motion. The frequencies of ion plasma waves, also called ion acoustic or plasma sound waves, depend on the electron and ion temperatures as well as on the ion mass. Both electron and ion waves, ie, electrostatic waves, are longitudinal in nature that is, they consist of compressions and rarefactions (areas of lower density, eg, the area between two compression waves) along the direction of motion. 

In a recent study of the transport of coarse solids in a horizontal pipeline of 38 mrrt diameter, pressure drop, as a function not only of mixture velocity (determined by an electromagnetic flowmeter) but also of in-line concentration of solids and liquid velocity. The solids concentration was determined using a y-ray absorption technique, which depends on the difference in the attenuation of y-rays by solid and liquid. The liquid velocity was determined by a sail injection method,1"1 in which a pulse of salt solution was injected into the flowing mixture, and the time taken for the pulse to travel between two electrode pairs a fixed distance apart was measured, It was then possible, using equation 5.17, to calculate the relative velocity of the liquid to the solids. This relative velocity was found to increase with particle size and to be of the same order as the terminal falling velocity of the particles in the liquid. 

To explain the photoelectric effect, Einstein (1905) postulated that light, or electromagnetic radiation, consists of a beam of particles, each of which travels at the same velocity c (the speed of light), where c has the value... 

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