| Macroscopic: A physical entity or process of large scale, the scale of ordinary human experience. Specifically, any phenomena in which the individual molecules and atoms are neither measured, nor explicitly considered in the description of the phenomena. |
| Magnehelic Gauge: A sensitive differential pressure or vacuum gauge 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. |
| Manifold: A pipe with several apertures for making multiple connections.
|
| manometer An instrument for measuring pressure. Usually, a manometer is a glass tube filled with a liquid that is used to measure the difference in pressure across a flow-measuring device such as an orifice or Venturi meter. The instrument used to measure blood pressure is a type of manometer.
|
| 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.
|
| Manual Reset (Adjustment): The adjustment on a proportioning controller which shifts the proportioning band in relationship to the set point to eliminate droop or offset errors.
|
| Manual Reset (Switch): The switch in a limit controller that manually resets the controller after the limit has been exceeded. |
| Mass Flow Rate: Volumetric flowrate times density, i.e. pounds per hour or kilograms per minute.
|
| Mass Storage: A device like a disk or magtape that can store large amounts of data readily accessible to the central processing unit.
|
| Mathematical Model: A mathematical equation or equations which can be used to numerically compute a system`s response to a particular input.
|
| Maximum Compression Ratio, Haskel: Because of the "volumetric efficiency" effects due to the gas compressibility and the "unswept volume", maximun pressures obtainable with gas boosters are not completely defined by the nominal booster ratio and the air drive pressure. The "maximum compression ratio" is defined as the ratio at which the volumetric efficiency becomes zero. |
| Maximum Current: Describes the size of a load that can be driven by an instrument with a Loop Impedance mA output. For example a 500 ohm maximum loop impedance means that the instrument can supply 10 volts at 20 mA into this load. |
| Maximum Excitation: The maximum value of excitation voltage or current that can be applied to the transducer at room conditions without causing damage or performance degradation beyond specified tolerances.
|
| Maximum Operating Temperature: The maximum temperature at which an instrument or sensor can be safely operated.
|
| Mean Temperature: The average of the maximum and minimum temperature of a process equilibrium.
|
| Measurand: A physical quantity, property, or condition which is measured. |
| Measured Media: The physical quantity, property, or condition which is measured. (eg: pressure, load, weight, acceleration)
|
| Measuring Junction: The thermocouple junction referred to as the hot junction that is used to measure an unknown temperature.
|
| Mechanical Hysteresis: The difference of the indication with increasing and decreasing strain loading, at identical strain values of the specimen.
|
| Mechatronics: The introduction of electronic controls into mechanical components.
|
| Megabyte: A million bytes. Technically, 1024 kilobytes. (or 1,048,576 bytes) |
| Melting Point: The temperature at which a substance transforms from a solid phase to a liquid phase.
|
| Membrane: The pH-sensitive glass bulb is the membrane across which the potential difference due to the formation of double layers with ion-exchange properties on the two swollen glass surfaces is developed. The membrane makes contact with and separates the internal element and filling solution from the sample solution.
|
| Meniscus: The curved top of a column of liquid (water, oil, mercury) in a small tube. When the liquid wets the sides of the container (as with water), the curve forms a valley. When the confining sides are not wetted (as with mercury), the curve forms a hill or upward bulge. |
| MESFET : Metal-semiconductor field-effect transistor |
| Meson: A hadron made from an even number of quark constituents The basic structure of most mesons is one quark and one antiquark. |
| 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.
|
| Metal: An opaque lustrous elemental chemical substance that is a good conductor of heat and electricity and, when polished, a good reflector of light; most elemental metals are malleable, ductile, and are generally denser than the other elemental substances; metals are structurally distinguished from nonmetals by their atomic bonding and electron availability; the electron band structure of metals is characterized by a partially filled valence band; the "free electrons" lost from the outer shells of metallic atoms are available to carry an electric current; the defining property of a metal is that it is an element with a positive thermal coefficient of resistivity, meaning the electrical resistivity of a metal continuously increases as temperature increases.
|
| Metallurgy: The science and technology of metals and alloys. |
| Metastable: (1) nonequilibrium state of a material with respect to some transition, conversion, or reaction but stabilized kinetically either by rapid cooling or by some molecular characteristics; (2) possessing a state of pseudoequilibrium that has a free energy higher than that of the true equilibrium state.
|
| Methanogenic: Referring to the formation of methane by certain anaerobic bacteria during the process of anaerobic fermentation.
|
| Method of Correction: A procedure whereby the mass distribution of a rotor is adjusted to reduce unbalance, or vibration due to unbalance, to an acceptable value. Corrections are usually made by adding material to, or removing it from, the rotor.
|
| MFLOPS: Million Floating Point Instructions Per Second.
|
| Mica: A transparent mineral used as window material in high-temperature ovens. |
| Microamp: One millionth of an ampere, 10-6 amps, ?A.
|
| Micron: One millionth of a meter (0.000001), and another term for micrometer (10^-6).
|
| Microvolt: One millionth of a volt, 10-6 volts.
|
| Mil: One thousandth of an inch (.001").
|
| Milliamp: One thousandth of an amp, 10-3 amps, symbol mA.
|
| Millimeter: One thousandth of a meter, symbol mm.
|
| Millivolt: Unit of electromotive force. It is the difference in potential required to make a current of 1 millampere flow through a resistance of 1 ohm; one thousandth of a volt, symbol mV.
|
| Milspec: Military specification. |
| MIME -- (Multipurpose Internet Mail Exte Originally a standard for defining the types of files attached to standard Internet mail messages. The MIME standard has come to be used in many situations where one computer program needs to communicate with another program about what kind of file is being sent.
For example, HTML files have a MIME-type of text/html, JPEG files are image/jpeg, etc.
|
| Mineral-insulated Thermocouple: A type of thermocouple cable which has an outer metal sheath and mineral (magnesium oxide) insulation inside separating a pair of thermocouple wires from themselves and from the outer sheath. This cable is usually drawn down to compact the mineral insulation and is available in diameters from .375 to .010 inches. It is ideally suited for high-temperature and severe-duty applications.
|
| Mineralization: The release of inorganic chemicals from organic matter in the process of aerobic or anaerobic decay.
|
| Minimum Spot Size: The diameter of the smallest object for which an instrument can meet its performance specifications.
|
| MIPS: Million Instructions Per Second.
|
| Mirror: Generally speaking, "to mirror" is to maintain an exact copy of something. Probably the most common use of the term on the Internet refers to "mirror sites" which are web sites, or FTP sites that maintain copies of material originated at another location, usually in order to provide more widespread access to the resource. For example, one site might create a library of software, and 5 other sites might maintain mirrors of that library. |
| MKSA: The system of physical units based on the fundamental metric units: meter kilogram, second and ampere.
|
| Modem: Modulator/Demodulator. A device that transforms digital signals into audio tones for transmission over telephone lines, and does the reverse for reception.
|
| Modulation: The process by which some characteristic of a higher frequency wave is varied in accordance with the amplitude of a lower frequency wave.
|
| Modulus of Elasticity (E) : The ratio of stress to strain when deformation is totally elastic; also a measure of the stiffness of a material.
|
| Modulus of Elasticity: A measure of the rigidity of metal. Ratio of stress, within proportional limit, to corresponding strain. Specifically, the modulus obtained in tension or compression is Young`s modulus, stretch modulus or modulus of extensibility; the modulus obtained in torsion or shear is modulus of rigidity, shear modulus or modulus of torsion; the modulus covering the ratio of the mean normal stress to the change in volume per unit volume is the bulk modulus. The tangent modulus and secant modulus are not restricted within the proportional limit; the former is the slope of the stress-strain curve at a specified point; the latter is the slope of a line from the origin to a specified point on the stress-strain curve. Also called elastic modulus and coefficient of elasticity.
|
| Modulus of Rupture: Breaking strength in a nonductile solid as measured by bending.
|
| 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.
|
| Molality: A measure of concentration expressed in mols per kilogram of solvent |
| Molecular mass: The molecular mass of something is the mass of one mole of it (in cgs units), or one kilomole of it (in MKS units). The units of molecular mass are gram and kilogram, respectively. The cgs and MKS values of molecular mass are numerically equal. The molecular mass is not the mass of one molecule |
| 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.
|
| Molecule: A group of atoms that are bound together by primary interatomic bonds.
|
| Monitor Provides a quantitative measurement, not qualitative. It measures continuously a condition that must be kept within prescribed limits. It does not differentiate between compounds. |
| Monovalent Ion: An ion with a single positive or negative charge (H+, C1-).
|
| Mosaic The first WWW browser that was available for the Macintosh, Windows,and UNIX all with the same interface. Mosaic really started the popularity of the Web. The source-code to Mosaic was licensed by several companies and used to create many other web browsers.
Mosaic was developed at the National Center for Supercomputing Applications (NCSA), at the Univeristy of Urbana-Champange in Illinois, USA. The first version was released in late 1993.
|
| MOSFET: Metal Oxide Semiconductor Field Effect Transistor. A class of voltage driven devices that does not require the large drive currents of bipolar devices. Used in products that require large current levels to be switched electronically.
|
| Motherboard: The pc board of a computer that contains the bus lines and edge connectors to accommodate other boards in the system. In a microcomputer, the motherboard contains the microprocessor and connectors for expansion boards.
|
| Mounted Resonant Frequency: The frequency at which the internal spring/mass system of an accelerometer resonates, producing a 90 degree phase shift in output signal vs. applied acceleration. |
| Mounting Error: The error resultant from installing the transducer, both electrical and mechanical. |
| MOX: A fuel composed of a mixture of plutonium dioxide and uranium dioxide.
|
| MPEG (Motion Picture Experts Group): An industry standard for compressing video and audio. MPEG I, used in video CDs, provides a standard image of 352x240 dots per inch, 30 frames per second, 15-bit color and CD-quality sound. MPEG II is an emerging standard for full broadcast-quality video. |
| MR: Magneto Resistive or Magneto-Resistance.
|
| MRI: Magnetic Resonance Imaging.
|
| MSD (Most-Significant Digit): The leftmost digit of the display.
|
| MTBF: Mean Time Between Failures. A measure of quality expressed in hours of life, stating the relative reliability of a component, circuit, or system. The average time before a failure will occur. The MTBF of a system or subsystem is a calculation taking into consideration the MTBF of each component in it. It is the statistical average operation time between the start of a unit?s lifetime and its time of failure.
|
| Mueller Bridge: A high-accuracy bridge configuration used to measure three-wire RTD thermometers.
|
| Multiplex: A technique which allows different input (or output) signals to use the same lines at different times, controlled by an external signal. Multiplexing is used to save on wiring and I/O ports. |
| Muon: The second flavour of charged leptons (in order of increasing mass), with electric charge -1. |
| mutagen An agent that causes a permanent genetic change in a cell other than that which occurs during normal genetic recombination.
|
| MUX: Multiplexer: A device that can take several different inputs, select which one is to be used at a specific time, and process the selected input through to a single output. This process is similar to the channel selector on your TV set. The opposite function is performed by a demultiplexer. |
Additions/Suggestions/Assistance
