For an isentropic flow, entropy density can vary between different streamlines.
2.
If the entropy density is the same everywhere, then flow is said to be homentropic.
3.
Apart from possibly greater entropy density of the files, and the ease of automation, there is little practical difference between such variants and traditional methods.
4.
Thus, we assume that there is an entropy flux, an entropy source, and an internal entropy density per unit mass ( \ eta ) in the region of interest.
5.
Also it is assumed that the local entropy density is the same function of the other local intensive variables as in equilibrium; this is called the local thermodynamic equilibrium assumption ( see also Keizer ( 1987 ) ).
6.
Such books were deemed dull enough to not arouse suspicion if an agent was searched ( particularly as the agents'cover stories were as businessmen ), and to have such high entropy density as to provide a very secure additive.
7.
Where \ frac { \ partial s _ c } { \ partial t } is the rate of increase in entropy density due to the irreversible processes of equilibration occurring in the fluid and \ mathbf { J } _ s is the entropy flux.
8.
If I remember correctly, the entropy density of a photon gas is 4 / 3 u / T where u is the energy density, which in turn can be related to the Stefan-Boltzmann law via sigma T ^ 4 = c / 4 u . talk ) 22 : 04, 21 April 2010 ( UTC)
9.
In the classical irreversible thermodynamic approach, there is allowed very small spatial variation, from very small volume element to adjacent very small volume element, but it is assumed that the global entropy of the system can be found by simple spatial integration of the local entropy density; this means that spatial structure cannot contribute as it properly should to the global entropy assessment for the system.
10.
Of course the figures from such a book are not actually uniformly distributed ( there is an excess of " 0 " and " 1 " ( see Benford's Law ), and sequential numbers are likely to be somewhat similar ), but nevertheless they have much higher entropy density than passphrases and the like; at any rate, in practice they seem never to have been successfully cryptanalysed.