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(analytical chemistry)
Measure of the clarity of an otherwise clear liquid by using colorimetric scales.
Cloudy or hazy appearance in a naturally clear liquid caused by a suspension of colloidal liquid droplets or fine solids.
The formation of disks centered on stars in long-exposure photographs as a result of light scattering by grains in the emulsion.
Any condition of the atmosphere which reduces its transparency to radiation, especially to visible radiation.



the capacity of an optically nonuniform medium to scatter light passing through it (see). The extinction coefficient is a quantitative characterization of turbidity and is given by the equation.

τ ═ (l/I) ln (I0/I)

where I0 and I are the intensities of a light beam before and after passage through a layer of the medium of thickness l. Turbidity is determined by methods of nephelometry and turbidimetry.

References in periodicals archive ?
(a) NTU = nephelometric turbidity units. TABLE 2 Inactivation of Klebsiella terrigena by Bleach, pH 7.5, 25[degrees]C Disinfectant Time CFU/mL Free Chlorine [Log.sub.10] (Min.) Residual (mg/L) Reduction Regular bleach 0 1.57 x 1.12 NA (a) [10.sup.7] 1 < 5 0.91 > 6.35 10 < 5 0.53 > 6.35 20 < 5 0.27 < 6.35 30 < 5 0.26 > 4.35 Anywhere 0 1.13 x 1.17 NA bleach [10.sup.7] 1 < 5 0.87 > 6.44 10 < 5 0.55 > 6.44 20 < 5 0.43 > 6.44 30 < 5 0.28 > 6.44 (a) NA = Not applicable.
For each time lag from 0 to 18 days, we estimated the excess daily rate of gastroenteritis associated with four levels of turbidity: 0.0-0.29, 0.3-0.49, 0.5-0.99, and 1.0-2.0 Nephelometric Turbidity Units (NTU).
Limits are set at five Nephelometric Turbidity Units (NTUs) above background - background being the section upstream not yet affected by dredging operations.
Turbidity is measured by using a turbidity meter which measures the amount of light that is scattered at 90o angle to the incident beam, and is usually stated in units of NTU (nephelometric turbidity units).
If I have a red wine sitting at less than 10 NTUs (nephelometric turbidity units), and especially if it's below 5, then I'm totally comfortable taking it to bottle unfiltered."
Turbidity (or the cloudiness of water) is measured in terms of Nephelometric Turbidity Units (NTU).
We examined turbidity in nephelometric turbidity units (NTU) using the Hach 2100N turbidimeter (detection range 0 to 4,000 NTU).