ČSN ISO 6107 - Kvalita vod - Slovník

3.599 uncertainty of measurement

non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand (3.31), based on the information used

Note 1 to entry: Measurement uncertainty includes components arising from systematic effects, such as components associated with corrections and the assigned quantity values of measurement standards, as well as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead, associated measurement uncertainty components are incorporated.

Note 2 to entry: In general, for a given set of information, it is understood that the measurement uncertainty is associated with a stated quantity value attributed to the measurand. A modification of this value results in a modification of the associated uncertainty.

3.600 unsaturated zone; vadose zone part of an aquifer (3.40, 3.41, 3.42) in which the pore spaces of the formation are not totally filled with water

3.601 viable bacteria bacteria (3.53) that are capable of multiplication and/or metabolism

3.602 Vibrio specie group of Gram-negative, aerobic, non-spore-forming bacteria which are widespread in surface waters and include pathogenic species such as V. cholerae, V. parahaemolyticus and V. fisheri

3.603 viruses large group of ultramicroscopic agents (20 nm to 300 nm in diameter) which essentially consist of nucleic acid encased in a protein shell and which reproduce only in living cells

Note 1 to entry: Viruses can pass through filters which retain bacteria.

3.604 volatile fatty acid short-chain saturated organic acid, mainly produced during anaerobic digestion