810 / 836
TEA
Total Exchangeable Acidity - A measure of
the amount of acidic cations (hydrogen,
aluminum, iron and manganese) present in
soil. It is expressed in Milliequivalents per 100
grams (meq/100 g) of soil.
°Th
Degree Thörner is determined by titrating a
10 mL sample diluted with twice its volume of
deionized or distilled water with 0.1 M sodium
hydroxide to a phenolphthalein end point.
Timer Function
Counts down to appropriate time interval
before a reading is displayed. This feature
ensures consistency in measurements.
TPTZ
2,4,6-tri-(2-pyridyl)-1,3,5-triazine
(iron
indicator)
Traceability [IUPAC]
Property of the result of a measurement
or the value of a standard whereby it can
be related to stated references, usually
national or international standards, through
an unbroken chain of comparisons all having
stated uncertainties. The concept is often
expressed by the adjective traceable. The
unbroken chain of comparisons is called a
traceability chain.
Turbidity
Turbidity of water is an optical property that
causes light to be scattered and absorbed,
rather than transmitted. The scattering
of the light that passes through a liquid is
primarily caused by the suspended solids.
The higher the turbidity, the greater the
amount of scattered light. Because even the
molecules in a very pure fluid scatter light to
a certain degree, no solution will have zero
turbidity.
UPW
Ultra Pure Water.
USB
Universal Serial Bus is a application to
establish communication between various
devices and a host controller (usually a PC).
USDA
United States Department of Agriculture.
USP
US Pharmacopoeia. USP <645> with Stage
1, 2 and 3 compliance is required for purified
water and WFI (water for injection). Hanna
offers instruments that are able to perform
all three stages required by this standard.
Some of these requirements are: Resolution
of 0.1 μS/cm or better, accuracy at 1.3μS/cm
of 0.1μS/cm, to be able to readwith or without
automatic temperature compensation, the
cell constant be known with an uncertainty
better than ±2%.
UV
Ultraviolet—electromagnetic radiation with
a wavelength shorter than that of VIS, but
longer than X-rays (10-400 nm).
VCO
Voltage Controlled Oscillator.
VIS
The visible spectrum - is the portion of the
electromagnetic spectrum that is visible (can
be detected by) to the human eye (390 - 750
nm for typical human eye).
WHO
World Health Organization.
Glossary
17
Glossary
17.18
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