M
M85: An alcohol fuel mixture containing 85 percent methanol and 15 percent gasoline by volume. Methanol is typically made from natural gas, but can also be derived from the fermentation of biomass.
Mannan: The polymer of mannose with a repeating unit of C6H10O5. Can be hydrolyzed to mannose.
Mannose: (C6H1206) A six-carbon sugar. A product of hydrolysis of mannan found in the hemicellulose fraction of biomass.
Mash: A mixture of grain and other ingredients with water to prepare wort for brewing operations.
Mass closure (%): The percent by weight of the total samples extracted from the biomass sample compared to the weight of the original sample. It is a sum of the weight percent of moisture, extractives, ash, protein, total lignin, acetic acid, uronic acids, arabinan, xylan, mannan, galactan, glucan, and starch. This is a good indicator of the accuracy of a complete biomass compositional analysis.
MBF: Abbreviation denoting 1,000 board feet. MBF is a typical unit of trade for dimension lumber and sawtimber stumpage.
Megawatt (MW): A measure of electrical power equal to 1 million watts (1000 kW).
Metabolism: The sum of the physical and chemical processes involved in the maintenance of life and by which energy is made available to the organism.
Merchantable Height: The stem length, measured from one foot above the ground to a 10-, 6-, or 4-inch diameter top, above which no other saleable product can be cut. Diameter, local markets, limbs, knots, and other defects collectively influence merchantable height.
Metabolic waste: substances left over from excretory processes, which cannot be used by the organism (they are surplus or have lethal effect), and must therefore be excreted.
Methane(CH4) is a hydrocarbon gas, the major component of natural gas. It can be formed by anaerobic digestion of biomass or gasification of coal or biomass.
Methanol (wood alcohol): (CH3OH) An alcohol formed by catalytically combining carbon monoxide with hydrogen in a 1:2 ratio under high temperature and pressure.
Microorganism: Any microscopic organism such as yeast, bacteria, fungi, etc.
Mill residue: Wood and bark residues produced in processing logs into lumber, plywood, and paper.
Mixed Stand: A timber stand containing two or more prominent species in the main canopy.
MMBtu: One million British thermal units.
Modified /unmodified diesel engine: Traditional diesel engines must be modified to heat the oil before it reaches the fuel injectors in order to handle straight vegetable oil. Modified, any diesel engine can run on veggie oil; without modification, the oil must first be converted to biodiesel.
Modulating fuel feed: A fuel feed system that adjusts the feed rate up or down in response to changes in the heat load.
Moisture: The amount of water and other components present in the biomass sample that are volatilized at 105°C. (Source: Ehrman, T. Standard Method for Determination of Total Solids in Biomass. NREL-LAP-001. Golden, CO: National Renewable Energy Laboratory, October 28, 1994.)
Moisture content (MC): The weight of the water contained in wood, usually expressed as a percentage of weight, either oven-dry or as received.
Moisture content, dry basis: Moisture content expressed as a percentage of the weight of oven-wood, that is, [(weight of wet sample – weight of dry sample) / weight of dry sample] × 100.
Moisture content, wet basis: Moisture content expressed as a percentage of the weight of wood as-received, that is, [(weight of wet sample – weight of dry sample) / weight of wet sample] × 100.
Moisture free basis: Biomass composition and chemical analysis data is typically reported on a moisture free or dry weight basis. Moisture (and some volatile matter) is removed prior to analytical testing by heating the sample at 105°C to constant weight. By definition, samples dried in this manner are considered moisture free.
Monoculture: The cultivation of a single species crop.
Monosaccharide: A simple sugar such as a five-carbon sugar (xylose, arabinose) or six-carbon sugar (glucose, fructose). Sucrose, on the other hand is a disaccharide, composed of a combination of two simple sugar units, glucose and fructose.
MTBE: Methy-tertiary-buty1 ether is highly refined high octane light distillate used in the blending of petrol.
Multi-chamber system: A variation on the two-chamber combustion system in which there is a connecting refractory-lined chamber between the combustor and boiler to give a longer flame path to enhance completeness of combustion.
Multi-clone (or multi-cyclone): A particulate removal device that includes a number of cyclone separators.
Municipal solid waste: Any organic matter, including sewage, industrial, and commercial wastes, from municipal waste collection systems. Municipal waste does not include agricultural and wood wastes or residues.