A fine-particle size, non-plastic, dense, brittle kaolinitic clay layer or deposit, that breaks with a conchoidal fracture. Typically found in association with coal layers.
Cf. underclay, seat rock

In the original, flocculation refers to the destabilization of a suspension by the clumping of small particles to larger ones, but without fusion, owing to small amounts of polymers (e.g., see Lyklema, 1991). Common usage is no longer restricted to polymers, and may involve changes of the electrolyte. However, the mechanisms of destabilization differ where polymers vs electrolytes are considered: polymers are adsorbed and form bridges between particles, whereas electrolyte changes involve ionic strength variations that reduce repulsive forces between particles. Both processes produce clumping of small particles in a suspension to produce larger particles. The total surface area does not essentially change.
Syn., aggregation

A cluster of loosely bound particles in a suspension that combine to produce a larger particle. In clay mineralogy, a floccule, or “floc”, is comprised of very fine-grained clay minerals in association with fine silt and organic debris, held together by electrostatic forces or organic sheaths (after Potter et al., 2005).
See flocculation.

An obsolete term for phlogopite.

An obsolete term for tainiolite.

a) In metallurgy, a material which chemically cleans a metal surface to prepare it for welding, brazing or soldering.

b) In ceramics, a material which lowers the meting point of ceramic materials to facilitate glass formation.

c) In physics, the rate of transfer of heat, mass, magnetism, etc. that passes a unit area per unit time.
Cf., fusion

Melting of a substance.

A dynamic bond where atoms exchange between symmetry-related sites. In cases where the configurations are non-equivalent, the result is an isomer or tautomer, whereas a fluxional molecule involves chemically equivalent configurations.

Fine particulate, airborne, typically amorphous, siliceous residue from burning coal in industrial burners. The chemistry of the coal and the type/chemistry of the fly ash collection system determines the composition of the fly ash. Pozzolanic (cementitious) fly ash is commonly used as an additive in cement. Non-pozzolanic fly ash is often used as a filler in wood and plastic products, in asphaltic concrete, in roofing tiles, and in other composite manufactured materials. Fly ash commonly contains a variety of heavy metals that were present in trace concentration in the unburned coal.
Cf., bottom ash

A force field is derived from a set of parameters determined from an approximate energy expression and then used to calculate interatomic or intermolecular energies in a classical calculation or simulation of an atomic structure. Most force field methods include pairwise interatomic interactions (e.g., van der Waals, electrostatic), and some include intramolecular interactions (e.g., bond stretch, angle bend) present in polyatomic species. Interaction parameters are adjusted so that results obtained from the force field, such as structural, mechanical, and spectroscopic properties, match those from experiment or quantum mechanical calculations as closely as possible.