Moisture equivalent

It is usually defined as the amormt of moisture held by a soil 1 cm thick when subjected to a centrifugal force of 1000 times that of gravity for 30 minutes corresponding to 2400 r.p.m. of the centrifuge. 

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A cane factory generates its own requirements for energy, from burning bagasse to produce electricity one tonne of mill run bagasse (50% moisture) > equivalent in fuel value, at 3,700 kj /kg (884 kcal/kg), to one barrel (159 L) of fuel oil. An efficient raw sugar or plantation white factory will use 70—80%... 

Moisture-Equivalent—Briggs and McLane (1907) made extensive physical studies on what has been termed moisture-equivalent — that is, the percentage of water retained by a soil, when the moisture content is reduced by means of a constant centrifugal force until it is brought into a state of capillary equilibrium. While King s procedure yields specific information on the relative retentiveness of various soils only after considerable time, the method of Briggs and McLane is rapid,... 

When the moisture-equivalent is plotted against the reciprocal of the centrifugal force, resulting curves for mpst soils and particularly for loose sands and loams containing small amounts of clay, are straight lines. If Me represents the moisture-equivalent for a given material and F the centrifugal force, then... 

Briggs and McLane investigated the moisture-equivalent of 104 soils, and on the basis of composition and particle-size distributions obtained the following relation ... 

Me = the moisture-equivalent in percent by weight A percent of soil in size range 2-0.25 mm B = percent of soil in size range 0.25-0.5 mm C = percent of soil in size range 0.05-0.005 mm D = percent of soil in size range 0.005 mm and less E = organic matter... 

The moisture-equivalent for a given centrifugal force is useful, but it is not certain that this actually represents capillary moisture as believed... 

Figure 74. Percent Moisture-Equivalent and Water-holding Capacity in Sand-silt Mixtures. (Yuma-mbsa Sandy Soil.) Numbers Refer to Analyses Given in Table 55.

Moisture-equivalent = hygroscopic coefficient X 2.71 = (moistureholding capacity — 21) X 0.635 = 0.02 percent sand + 0.22 percent silt + 1.05 percent clay Eq (14-6)... 

Moisture-holding capacity = (moisture-equivalent X 1.57) + 21 = (hygroscopic coefficient X 4.26) + 21 = 0.03 percent sand + 0.35 percent silt + 1.65 percent clay + 21 Eq (14-7)... 

Hygroscopic coefficient = moisture-equivalent X 0.37 =. (moisture-holding capacity — 21) X 0.234 = 0.007 percent sand + 0.082 percent silt + 0.39 percent clay Eq (14-8)... 

In these equations the moisture-equivalents are based on a centrifugal force of 1000 times gravity. The particle-size of sand, silt, and clay (used in the experiments, and for which the equations apply) is ... 

Total porosity minus moisture-equivalent (volume). 

Total porosity minus moisture-equivalent (volume) corrected for texture by a method attributed to Harding (1919). Harding s method is to correct the moisture-equivalent by a multiplier which takes into account texture of the soil. 

Note also how voids are highly correlated with aggregation (0.57), silt and clay (0.70), volume-weight (—0.99), and moisture-equivalent (0.82). 

Relation of the moisture equivalent of soils to the moisture properties under field conditions of irrigation. Soil Science, 8 303-312. 

Dry the hide powders in an oven for 16 h and cool in a desiccator. Add 1 ml of 3% chrome alum CrK(SO )2 solution for each gram of air-dried hide powders at 25 2 °C for 2 h. Wash the pretanned hide powders thoroughly with water at 25 2 °C. Filter the suspended hide powders and squeeze the powders to obtain about 75% of the moisture in the powders. Weigh 50 g of the wet hide powders (containing approximately 75% moisture), equivalent to 12.5 0.3 g of dried powders, and add them to a 200 ml volumetric flask. Fill the flask with testing solution to the 200 ml mark. Close the bottle and keep the solution at 25 2 °C for 15 min. Filter the solution immediately into a beaker containing 2 g of kaolin. 

Cut Whatman No 2 filter paper (square shape) and fix properly on the wire gauged bottom of the moisture equivalent boxes. 

The saturated paste method provides an estimate of salt in soil at normal field moisture equivalents. Saturation percentage is about four times the 15-atmosphere moisture equivalent or permanent wilting point (irreversible plant desiccation), and approximately two times the 0.33 atmosphere moisture equivalent or field capacity (moisture held in soil against drainage by gravity). Soil with a saturated paste EC of... 

Type of peat Location Depth (inches) in dry peat (%) Volume wt. (g) Maximum moisture-holding capacity %) Moisture equivalent (%) Air-dry moisture (%) Apparent specific gravity Absolute Maxispecific mum ... 

Registered Tradename Common Name TSCA Number Amine Number Gardner Color Iodine Value Moisture % Equivalent Weight Melting Point Amine Number... 

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