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  2. Respiratory quotient - Wikipedia

    en.wikipedia.org/wiki/Respiratory_quotient

    The respiratory exchange ratio (RER) is the ratio between the metabolic production of carbon dioxide (CO 2) and the uptake of oxygen (O 2). [3] [4] The ratio is determined by comparing exhaled gases to room air. Measuring this ratio is equal to RQ only at rest or during mild to moderate aerobic exercise without the accumulation of lactate.

  3. Ozone–oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Ozone–oxygen_cycle

    This wavelength regime has the highest cross section for this reaction (10 −17 cm 2 per oxygen molecule), and thus the rate of oxygen photodissociation per oxygen molecule decreases significantly at these altitudes, from more than 10 −7 per second (about once a month) at 100 km to 10 −8 per second (about once every few years) at 80 km . [4]

  4. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Photosynthetic prokaryotic organisms that produced O 2 as a byproduct lived long before the first build-up of free oxygen in the atmosphere, [5] perhaps as early as 3.5 billion years ago. The oxygen cyanobacteria produced would have been rapidly removed from the oceans by weathering of reducing minerals, [citation needed] most notably ferrous ...

  5. Running economy - Wikipedia

    en.wikipedia.org/wiki/Running_economy

    Running economy (RE) a complex, multifactorial concept that represents the sum of metabolic, cardiorespiratory, biomechanical and neuromuscular efficiency during running. [1]: 33 [2] [3] Oxygen consumption (VO 2) is the most commonly used method for measuring running economy, as the exchange of gases in the body, specifically oxygen and carbon dioxide, closely reflects energy metabolism.

  6. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    = milligrams of pollutant per cubic meter of air at sea level atmospheric pressure and T: ppmv = air pollutant concentration, in parts per million by volume T = ambient temperature in K = 273. + °C 0.082057338 = Universal gas constant in L atm mol −1 K −1: M = molecular mass (or molecular weight) of the air pollutant

  7. Oxygen storage - Wikipedia

    en.wikipedia.org/wiki/Oxygen_storage

    Introduction of interstitial oxygen into the structure results in the formation of oxygen-loaded phases having different symmetries: R3c (δ ≈ 0.28, Hex1) and Pca2 1 (δ ≈ 0.41, Hex2). The operating temperature range of those type of materials in an air atmosphere, could be as low as 200-300 ˚C and as narrow as 20 ˚C. [9]

  8. Oxygen equivalent - Wikipedia

    en.wikipedia.org/wiki/Oxygen_Equivalent

    Oxygen equivalent compares the relative amount of oxygen available for respiration at a variable pressure to that available at SATP.As external respiration depends on the exchange of gases due to partial pressures across a semipermeable membrane and normally occurs at SATP, an oxygen equivalent may aid in recognizing and managing variable oxygen availability during procedures such as ...

  9. Scuba gas planning - Wikipedia

    en.wikipedia.org/wiki/Scuba_gas_planning

    Nitrox is generally understood as air enriched by additional oxygen, as that is the usual method for producing it. Gas fraction of oxygen may range from 22% to 99%, but is more usually in the range of 25% to 40% for bottom gas (breathed during the main part of the dive), and 32 to 80% for decompression mixtures. [2]