M
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MAC values
Abbreviation for maximum allowable concentration, the highest permissible concentration of a material as gas, vapor or suspended matter in the air of a place of work, which according to the latest knowledge, does not impair the health of the workers or cause for excessive disturbance. This is based on current knowledge pertaining to repeated and long-term effects of exposure with an average of eight-hour days and up to 40 hour weeks. Usually the MAC value is given as an average value over time periods up to one work day or one work shift. In addition to this, there are limitations for peak concentrations. Creation of MAC values is primarily based on the active characteristics of the materials. The values are based on scientifically well-founded criteria for health protection as opposed to the technical and economic possibilities of practical implementation. Current MAC values can be obtained from the German Research Foundation (DFG) in Bonn / Bad Godesberg.
Material cycle
Technologies used to prepare old materials and remnants so that they can be used as basic materials or additives in production procedures. See: Recycling.
Maximum allowable concentration
See: MAC values.
Maximum amounts
Maximum amounts refer to:
1. legally acceptable quantities of substances such as pesticide agents, growth regulators and heavy metals in plant and animal food products listed in ppm
2. the value of the remaining quantities that can be accepted due to health, whereas tolerances (See: Tolerance) describe the values accepted by lawmakers, which is usually a lower value than the maximum amounts
Mechanical sewage treatment
First cleaning phase consisting of eliminating suspended solids.
Mercaptans
Thioalcohols, CnH2n+1SH: liquids that have an extremely repulsive smell, with the exception of the gaseous methylmercaptan. Used as an additive to clearly identify odorless natural gases.
Mercury
Symbol: Hg. The only metal that is liquid at room temperature. It has a lower electrical conductivity than most other metals. In its pure form, mercury is shiny metallic silver. The vapors of the metal are damaging to health (long-term exposure leads to chronic damage: insomnia, character changes, anxiety, shaky hands, so-called tremor mercurialis. Exposure over a very long time can lead to kidney damage). If no serious kidney damage is present, all symptoms are reversible. Mercury dissolves a variety of metals to form amalgams (mercury alloy). The content found in sea water and the atmosphere is extremely varied and depends on the geographical location of measurement. This is due to the fact that mercury is primarily released by volcanic activity. Seeing as how the concentration of mercury in fresh water is also affected by the geological and natural surroundings, the natural content of mercury in a body of water is not a given. Global production is approximately 8,000 tons/year. Mercury has many areas of application (physical measuring instruments, rectifiers, cathode metal in electrolysis, etc.). On the other hand, mercury compounds have almost no important usage today because applications such as dressing grain as a slimicide and in paper production have long been prohibited in Germany.
Methyl alcohol
Methanol, carbinol, CH3OH, simplest alcohol. Colorless, poisonous, burning tasting liquid; burns with a weakly lit flame and can be mixed with water. Produced in the wood carbonization process (wood spirits) and derived primarily in large technology processes from carbon monoxide, e.g. hydrogen at 380° C and 200 bars of pressure with chrome-zinc oxide as a catalyst. Methyl alcohol poisoning causes stomach aches, vomiting, cramps and leads to blindness. In serious cases it can cause death. The deadly dosage is about 20 grams. It is used as a solvent, for the manufacture of many organic intermediate products, rocket fuel, antifreeze and as an additive in motor fuels.
Micron
Milligram
Unit of measure: mg. Equal to 1 thousandth of a gram.
Moisture
This term is used to describe amount of water in a material, which is not chemically bound to the material. It is often used to denote air humidity as pertains to water vapor content. Absolute moisture: water vapor content in g/m3. Specific moisture: water vapor content in g/kg of air.
Molecule
Elements can exist in molecular form (e.g. oxygen as O2 or as O3 = ozone).
MON
Motor octane number, the Octane number that is derived under difficult conditions.
Municipal waste TI
See: TI