NLS-Glossary

Absolute displacement transducer

An absolute displacement transducer measures the distance to an object and supplies a signal proportional to the displacement. These transducers are based on various physical principles.

Absolute Pressure

is pressure relative to zero pressure in an empty space (i.e. a vacuum). the gauge (relative) pressure prel is the pressure compared with atmospheric pressure pamb (surrounding air pressure).

Absolute value

In a magnetic coded measuring system, each position or measurement section is coded to an absolute analog value or digital signal.
In mathematics, the absolute value or modulus of a real number x, denoted |x|, is the non-negative value of x without regard to its sign. Namely, |x| = x if x is positive, and |x| = −x if x is negative (in which case −x is positive), and |0| = 0. For example, the absolute value of 3 is 3, and the absolute value of −3 is also 3. The absolute value of a number may be thought of as its distance from zero.

Absorbance

Synonyms :
Optical density

Absorbance (A) is the flip-side of transmittance and states how much of the light the sample absorbed. It is also referred to as “optical density“ A=log10(1/T). for samples which scatter light, absorbance may be defined as the negative logarithm of one minus absorptance, as measured on a uniform sample. The term is used in many technical areas to quantify the results of an experimental measurement.

Absorptance

Synonyms :
Absorptivity

quotient of absorbed radiant flux and incident radiant flux, expressed by α=ΦaΦm where Φais absorbed radiant flux and Φm is incident radiant flux. This quantity is also defined spectrally in terms of wavelength, in which case “spectral” is added before the quantity name.
Due to energy conservation, α + ρ + τ = 1 except when polarized radiation is observed, where ρ is reflectance and τ is transmittance.

Absorptiometer

An instrument that measures absorption of light, esp by a solution.