Glossary

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 magnehelic gauge

a sensitive differential pressure or vacuum gauge manufactured by Dwyer Instrument Co. that uses a precision diaphragm to measure pressure differences. This gauge is manufactured in specific pressure or vacuum ranges such as 0 to 2 inches of water column. Magnehelic gauges are typically used to measure SVE system vacuums.

 Majors

Large multinational oil companies involved in all aspects of oil production, including both upstream and downstream activities.

 manifold

a pipe with several apertures for making multiple connections.

 manometer

an instrument for measuring fluid pressure. Typically a U-shaped tube in which opposing fluid pressures reach an equilibrium. The pressure is equal to the differences in the levels of the fluid on either side of the tube.

 Marketer

Any company or person that retails (sells) motor fuels. May or may not sell branded gasoline.

 metabolism

a term that encompasses all of the diverse reactions by which a cell processes food material to obtain energy and the compounds from which new cell components are made.

 methanogenic

referring to the formation of methane by certain anaerobic bacteria during the process of anaerobic fermentation.

 microaerophilic

obligate aerobes that function best under conditions of low oxygen concentration.

 microcosm

a diminutive, representative system analogous to a larger system in composition, development, or configuration. As used in biodegradation treatability studies, microcosms are typically constructed in glass bottles or jars.

 microorganisms

microscopic organisms including bacteria, protozoans, yeast, fungi, mold, viruses, and algae.

 mineralization

the release of inorganic chemicals from organic matter in the process of aerobic or anaerobic decay.

 moisture content

the amount of water lost from a soil upon drying to a constant weight, expressed as the weight per unit weight of dry soil or as the volume of water per unit bulk volume of the soil. For a fully saturated medium, moisture content equals the porosity.

 molecular diffusion

process whereby molecules of various gases tend to intermingle and eventually become uniformly dispersed.

 molecular weight

the amount of mass in one mole of molecules of a substance as determined by summing the masses of the individual atoms which make up the molecule.

 monoaromatic

aromatic hydrocarbons containing a single benzene ring.

 MPD s Multiple Product Dispenser

many people believe these to be pumps. Most MPD s have six hoses and dispense all three grades of fuel.