Differential diagnostics are examination procedures for the identification of illnesses and differentiation between similar symptomatic patterns. In the more extensive approach, these methods may be directed towards the same symptomatic patterns of different genetic background (origins of the illness).
The concept of DIRECT PUSH technologies covers a group of sampling technologies in which hollow steel tubes are driven or pressed into underground structures. This permits cost-effective and rapid examination of the underground although such technology is in fact restricted to unconsolidated sediments. A variety of different samplers may be attached to the tip of the steel tubes. These samplers permit the extraction of groundwater, soil/air or solid soil from the underground, detection of contamination by pollutants in situ or the measurement of physical parameters (e.g. hydraulic or electrical permeability). Measurement of these variable parameters may be undertaken continuously during the sampling procedure meaning that high resolution vertical profiles can readily be recorded.
In chemical terms, a dispersion is a mixture/blend of at least two substances which are not, or are scarcely soluble in each other, or are chemically combined with each other. As a rule colloids are involved.
In hydrogeological terms, the extent to which a liquid substance introduced into a ground-water system spreads as it moves through the system (definition by USGS; http://capp.water.usgs.gov/GIP/h2o_gloss).