User:RockMagnetist (DCO visiting scholar)/sandbox

Nikolay V. Sobolev
World expert on mantle mineralogy and petrology based on diamonds and their inclusions. IMA medal.

Abundance of elements
(For Geochemistry.)

Geochemists cannot access most of the Earth, so estimates of its bulk composition are obtained by piecing together three kinds of information. First, it is assumed that, aside from being depleted in volatiles, the Earth has a similar composition to the primordial Solar System. Second, the seismic velocity structure of the Earth is combined with mineral physics data for appropriate temperatures and pressures. Third, a model is chosen for the bulk composition of the Earth's mantle.

Chondritic models: of the primitive meteorites, only the enstatite chondrites, which are high in the mineral enstatite (MgSiO3), match the isotope chemistry and redox state of the Earth.

Residence time articles
There is a lot of overlap; they should probably be merged.
 * Lake retention time - focussed on this specific application
 * Space time (chemical engineering)

Waste stabilization ponds
Very high pathogen removal efficiencies may be achieved, depending on several factors: temperature, hydraulic retention time (the amount of time the liquid remains in the system - from entrance to exit), the number of ponds in the series, the presence of baffles and the depth of ponds.

Uses of fugacity

 * measure of the flow of mass in a chemical process
 * useful for chemical equilibrium calculations
 * better behaved than chemical potential at low pressure
 * often known as escaping tendency - can describe ease with which mass flows from one phase to another
 * in some cases it becomes the vapor pressure

Goldschmidt
Quote from Goldschmidt: "The basic problem of geochemistry is to determine the quantitative chemical composition of the earth and to find the laws which underlie the frequency and distribution of the various elements in nature" (Rosbaud, cited in Kauffman).

Power-law rates
A common form for the rate equation is a power law:
 * $$r = k[A]^a[B]^b \ldots$$

For example, in a dilute solution, an elementary reaction (one having a single step with a single transition state) is empirically found to obey the law of mass action. This predicts that the rate depends only on the concentrations of the reactants, raised to the powers of their stoichiometric coefficients.

Partition coefficient
Useful concept in geochemistry of trace elements and isotopes. See 2.2 Elemental fractionation in Albarede, "Geochemistry: An Introduction".

Claude ZoBell
Sources: