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  2. Certified reference materials - Wikipedia

    en.wikipedia.org/wiki/Certified_reference_materials

    A certified reference material is a particular form of measurement standard. Reference materials are particularly important for analytical chemistry and clinical analysis. [ 2 ] Since most analytical instrumentation is comparative, it requires a sample of known composition (reference material) for accurate calibration.

  3. Real versus nominal value (philosophy) - Wikipedia

    en.wikipedia.org/wiki/Real_versus_nominal_value...

    Traction power networks routinely operate well above the nominal voltage, but still within the tolerance. For example, a streetcar traction power could be rated 600 ±10% volts nominal, but the actual overhead line voltage would normally be close to 660 volts, only dropping near the nominal value in exceptional conditions.

  4. Respirator assigned protection factors - Wikipedia

    en.wikipedia.org/wiki/Respirator_Assigned...

    The respiratory protective devices (RPD) can protect workers only if their protective properties are adequate to the conditions in the workplace.Therefore, specialists have developed criteria for the selection of proper, adequate respirators, including the Assigned Protection Factors (APF) - the decrease of the concentration of harmful substances in the inhaled air, which (is expected) to be ...

  5. Real and nominal value - Wikipedia

    en.wikipedia.org/wiki/Real_and_nominal_value

    If for years 1 and 2 (possibly a span of 20 years apart), the nominal wage and price level P of goods are respectively nominal wage rate: $10 in year 1 and $16 in year 2 price level: 1.00 in year 1 and 1.333 in year 2, then real wages using year 1 as the base year are respectively: $10 (= $10/1.00) in year 1 and $12 (= $16/1.333) in year 2.

  6. Calibration curve - Wikipedia

    en.wikipedia.org/wiki/Calibration_curve

    A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]

  7. Concentration - Wikipedia

    en.wikipedia.org/wiki/Concentration

    In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration. [1]

  8. Equivalent concentration - Wikipedia

    en.wikipedia.org/wiki/Equivalent_concentration

    Normality is defined as the number of gram or mole equivalents of solute present in one liter of solution.The SI unit of normality is equivalents per liter (Eq/L). = where N is normality, m sol is the mass of solute in grams, EW sol is the equivalent weight of solute, and V soln is the volume of the entire solution in liters.

  9. Professional certification - Wikipedia

    en.wikipedia.org/wiki/Professional_certification

    A certification is a third-party attestation of an individual's level of knowledge or proficiency in a certain industry or profession. They are granted by authorities in the field, such as professional societies and universities, or by private certificate-granting agencies.