Particle length, determination

A typical virus with helical symmetry is the tobacco mosaic virus (TMV). This is an RNA virus in which the 2130 identical protein subunits (each 158 amino acids in length) are arranged in a helix. In TMV, the helix has 16 1/2 subunits per turn and the overall dimensions of the virus particle are 18 X 300 nm. The lengths of helical viruses are determined by the length of the nucleic acid, but the width of the helical virus particle is determined by the size and packing of the protein subunits. 

The measurement of Es and E, during a constant current step of time xs leads to the determination of the diffusion constant DGITT of an ion in a solid electrode with a particle length of r. 

If the particle-size distribution of a powder composed of hard, smooth s eres is measured by any of the techniques, the measured values should be identical. However, there are many different size distributions that can be defined for any powder made up of nonspheri-cal particles. For example, if a rod-shaped particle is placed on a sieve, its diameter, not its length, determines the size of aperture through which it will pass. If, however, the particle is allowed to settle in a viscous fluid, the calculated diameter of a sphere of the same substance that would have the same falling speed in the same fluid (i.e., the Stokes diameter) is taken as the appropriate size parameter of the particle. 

Oxidation Rate of Mn near the Sediment-Water Interface. We used a box model approach to calculate rates of the Mn redox cycle from sediment-trap data and in situ sampling techniques (peeper and lander experiments). Figure 1 depicts an overview of the relevant processes and length scales. Sedimentation rates of particles were determined with sediment traps at 81 time intervals of about 2 weeks during 1988-1991 and at three depths (z = 20, 81, and 86 m). 

The shear stress is easily estimated. Let the shock pressure be P(x,y,z,t) = Pq sin(2 rx/A) u(z-vt,y) where Pq is the shock wave pressure and A is the wave length. The shear stress is then i(x,y,z,t) = grad P(x,y,z,t) dr = (2. /A)PoCos(2nx/A)/where /is the average crystal particle size. Determination of the local energy dissipation rate can be obtained from Equation (14). It is predicted that initiation will first occur where the shear stress and the energy dissipation rate are greatest so that initiation will first occur at x = mA/2, where m = 0, 1,2, etc. On the x,y plane first initiation... 

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