WITH a typical liquid mass diffusivity in the order of 10 " 9 m 2 / s, the characteristic time for diffusion through a 20 micron thick liquid layer is 0.4 s.
22.
If a Maxwell material is suddenly deformed and held to a strain of \ varepsilon _ 0, then the stress decays with a characteristic time of \ frac { \ eta } { E }.
23.
The equation indicates that the decay constant has units of " ", and can thus also be represented as 1 /, where is a characteristic time of the process called the " time constant ".
24.
At TeleDanmark Research in the late 1980s and early 1990s Tromborg and colleagues worked to study the dynamics of active semiconductor materials in order to understand the physical relaxation processes at play, their strength and characteristic time scales.
25.
This image may taken over a long period ( relative to characteristics times scales within the flow ) to produce time-averaged images or alternatively using a single laser pulse ( approximately 10ns ) to obtain a measurement of instantaneous flow velocities.
26.
This relaxation process is described by the spin-lattice relaxation time T 1, which is a characteristic time needed by the magnetization to return to the z-axis, and by the spin-spin relaxation time T 2, which describes the vanishing time of the magnetization in the xy-plane.
27.
Formally, the Deborah number is defined as the ratio of the relaxation time characterizing the time it takes for a material to adjust to applied stresses or deformations, and the characteristic time scale of an experiment ( or a computer simulation ) probing the response of the material:
28.
For instance, a certain class of solutions to the Ricci flow demonstrates that "'neckpinch singularities "'will form on an evolving " n "-dimensional metric Riemannian manifold having a certain topological property ( positive Euler characteristic ), as the flow approaches some characteristic time t _ { 0 }.
29.
On supercooling a liquid towards the glass transition, the crossover from liquid-like to solid-like response moves from GHz to MHz, kHz, Hz, . . .; equivalently, the characteristic time of structural relaxation increases from ns to ?s, ms, s, . . . This is the microscopic explanation for the above-mentioned viscoelastic behaviour of glass-forming liquids.
30.
Another limitation of MHD ( and fluid theories in general ) is that they depend on the assumption that the plasma is strongly collisional ( this is the first criterion listed above ), so that the time scale of collisions is shorter than the other characteristic times in the system, and the particle distributions are Maxwellian.
