water content

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water content 

Water in a contact lens expressed as a percentage of the total mass of the lens in its hydrated state under equilibrium conditions with physiological saline solution containing 9 g/l sodium chloride at a temperature of 20 ± 0.5ºC and with a stated pH value.
where M is the mass of hydrated lens, m is the mass of dry lens.The US Food and Drug Administration (FDA) has categorized hydrogel contact lenses into four groups according to their water content and their surface reactivity (referred to as ionic if it contains more than 0.2% ionic material, and nonionic otherwise). Group 1: water content less than 50% and non-ionic. Group 2: water content greater than 50% and non-ionic. Group 3: water content less than 50% and ionic. Group 4: water content greater than 50% and ionic.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
Since the gravimetric water content was low in such untreated and treated soils, these studies have mainly tested the soils for compaction, unconfined compression strength, and Atterberg limits.
In order to measure the gravimetric water content, a balance was used to measure the weight of sample at variable time intervals.
After attaining equilibrium at each given pressure head, the tubes were removed from the centrifuge to determine the gravimetric water content of the mixture.
We determined KCl-extractable-N, gravimetric water content, and pH (in 1:1 DI [H.sub.2]O to soil suspension and 1: 1 0.01 M CaCl2 to soil suspension) at the end of the greenhouse trial.
aliena beetles in field cages (F = 2.5; df = 2,22; P = 0.10), most likely due to low egg recovery as a result of hot, dry field conditions accounting for up to 17% moisture loss in cages despite shade from rain shelters (as determined by gravimetric water content by mass at the end of the experiment).
The samples were mixed and split into two subsamples, the first to determine the gravimetric water content (w), and the second to determine the extractable ions and cation exchange capacity (CEC).
Under controlled temperature and equalised gravimetric water content in the laboratory, biochar amendment suppressed soil CO2 emissions by 53 per cent and net soil CO2 eq.
On the same diagram the gravimetric water content W (gravimetric moisture content in percent, the lines leaving the left bottom top) and humidity coefficient (degree) [S.sub.r] (the lines leaving the right bottom top) are reflected.
The initial geostatistical data analysis showed that the physical properties of the soil (clay, silt, sand, and gravimetric water content) showed no trend, then being possible the estimate of the variable using the original data with ordinary kriging.
It was shown that the output resistance varied from 2.5 to 4.0 MO given a change of 15 to 35% in the gravimetric water content. Stacheder et al.