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  2. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    Correcting concentrations for altitude. Air pollutant concentrations expressed as mass per unit volume of atmospheric air (e.g., mg/m 3, μg/m 3, etc.) at sea level will decrease with increasing altitude. The concentration decrease is directly proportional to the pressure decrease with increasing altitude.

  3. Grade (slope) - Wikipedia

    en.wikipedia.org/wiki/Grade_(slope)

    The grade (US) or gradient (UK) (also called stepth, slope, incline, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt".

  4. Useful conversions and formulas for air dispersion modeling

    en.wikipedia.org/wiki/Useful_conversions_and...

    Wind speed conversion factors. Meteorological data includes wind speeds which may be expressed as statute miles per hour, knots, or meters per second. Here are the conversion factors for those various expressions of wind speed: 1 m/s = 2.237 statute mile/h = 1.944 knots. 1 knot = 1.151 statute mile/h = 0.514 m/s.

  5. Sonic logging - Wikipedia

    en.wikipedia.org/wiki/Sonic_logging

    Many relationships between travel time and porosity have been proposed, the most commonly accepted is the Wyllie time-average equation. The equation basically holds that the total travel time recorded on the log is the sum of the time the sonic wave spends travelling the solid part of the rock, called the rock matrix and the time spent travelling through the fluids in the pores.

  6. Foot–pound–second system of units - Wikipedia

    en.wikipedia.org/wiki/Foot–pound–second...

    Molar units. The unit of substance in the FPS system is the pound-mole (lb-mol) = 273.16 × 1024. Until the SI decided to adopt the gram-mole, the mole was directly derived from the mass unit as (mass unit)/ (atomic mass unit). The unit (lbf⋅s 2 /ft)-mol also appears in a former definition of the atmosphere.

  7. Parshall flume - Wikipedia

    en.wikipedia.org/wiki/Parshall_flume

    The Parshall flume is an open channel flow-metering device that was developed to measure the flow of surface water and irrigation flow. The Parshall flume is a modified version of the Venturi flume. Named after its creator, Dr. Ralph L. Parshall of the U.S. Soil Conservation Service, the Parshall flume is a fixed hydraulic structure used in ...

  8. Volumetric flow rate - Wikipedia

    en.wikipedia.org/wiki/Volumetric_flow_rate

    v. t. e. In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol Q (sometimes ). It contrasts with mass flow rate, which is the other main type of fluid flow rate.

  9. Surface feet per minute - Wikipedia

    en.wikipedia.org/wiki/Surface_feet_per_minute

    SFM is a combination of diameter and the velocity (RPM) of the material measured in feet-per-minute as the spindle of a milling machine or lathe. 1 SFM equals 0.00508 surface meter per second (meter per second, or m/s, is the SI unit of speed). The faster the spindle turns, and/or the larger the diameter, the higher the SFM.