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  2. Useful conversions and formulas for air dispersion modeling

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

    For example, such a regulation might limit the concentration of NOx to 55 ppmv in a dry combustion exhaust gas corrected to 3 volume percent O 2. As another example, a regulation might limit the concentration of particulate matter to 0.1 grain per standard cubic foot (i.e., scf) of dry exhaust gas corrected to 12 volume percent CO 2.

  3. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    As the concentration increases the colour becomes a more vibrant yellow, then orange, with the final 10,000 ppm a deep red colour. In science and engineering , the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities , e.g. mole fraction or mass fraction .

  4. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    As an example, a measured NO x concentration of 45 ppmv in a dry gas having 5 volume % O 2 is: 45 × ( 20.9 - 3 ) ÷ ( 20.9 - 5 ) = 50.7 ppmv of NO x. when corrected to a dry gas having a specified reference O 2 content of 3 volume %. Note: The measured gas concentration C m must first be corrected to a dry basis before using the above equation.

  5. Propylene - Wikipedia

    en.wikipedia.org/wiki/Propylene

    Observed concentrations have been in the range of 0.1–4.8 parts per billion in rural air, 4–10.5 ppb in urban air, and 7–260 ppb in industrial air samples. [ 9 ] In the United States and some European countries a threshold limit value of 500 parts per million ( ppm ) was established for occupational (8-hour time-weighted average ) exposure.

  6. Graphite furnace atomic absorption - Wikipedia

    en.wikipedia.org/wiki/Graphite_furnace_atomic...

    Concentration measurements are usually determined from a working curve after calibrating the instrument with standards of known concentration. The main advantages of the graphite furnace comparing to aspiration atomic absorption are the following: The detection limits for the graphite furnace fall in the ppb range for most elements

  7. Fans Are Showing No Mercy After Subway Launches Their Most ...

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    Fans on social media have expressed their shock over Subway's new Doritos Footlong Nachos.

  8. Tunable diode laser absorption spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Tunable_diode_laser...

    Tunable diode laser absorption spectroscopy (TDLAS, sometimes referred to as TDLS, TLS or TLAS [1]) is a technique for measuring the concentration of certain species such as methane, water vapor and many more, in a gaseous mixture using tunable diode lasers and laser absorption spectrometry.

  9. Luukkonen makes 35 saves to help the Sabres spoil the ... - AOL

    www.aol.com/luukkonen-makes-35-saves-help...

    Ukko-Pekka Luukkonen made 35 saves, Jack Quinn scored twice and the Buffalo Sabres spoiled the Ottawa Senators’ homecoming with a 4-0 victory Thursday night. Dylan Cozens and Ryan McLeod also ...