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The next quality standard in the hierarchy is known as a secondary standard. Secondary standards are calibrated with reference to a primary standard. [2] The third level of standard, a standard which is periodically calibrated against a secondary standard, is known as a working standard. [2] Working standards are used for the calibration of ...
A standard solution created from a secondary standard cannot have its concentration accurately known without stoichiometric analysis against a primary standard. An example of a secondary standard is sodium hydroxide, a hydroscopic compound that is highly reactive with its surroundings. The concentration of a standard solution made with sodium ...
Secondary standards are calibrated with reference to a primary standard. Working standards, used to calibrate (or check) measuring instruments or other material measures, are calibrated with respect to secondary standards. The hierarchy preserves the quality of the higher standards. [20] An example of a standard would be gauge blocks for
Secondary chemical reference substance: substance whose characteristics are assigned and/or calibrated by comparison with a primary chemical reference substance. The United States National Institute of Standards and Technology (NIST) uses the trade marked term [ 12 ] Standard Reference Material (SRM) to denote a certified reference material ...
Secondary standards are designed to protect public welfare, damage to property, transportation hazards, economic values, and personal comfort and well-being from any known or anticipated adverse effects of a pollutant. A district meeting a given standard is known as an "attainment area" for that standard, and otherwise a "non-attainment area". [2]
Secondary instruments must be calibrated against a primary standard. For example: a dial bourdon tube type pressure gauge must be calibrated against a water or mercury U tube to assure good accuracy. Time. The earth moving in its orbit is primary. Clocks must be calibrated against it.
The standard deduction rises almost every year, and it can vary depending on your tax filing status. For tax year 2024—return you will file in 2025—the standard deduction amounts are: Head of ...
The formal definition of calibration by the International Bureau of Weights and Measures (BIPM) is the following: "Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or ...