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Some texts use the older, equivalent units me/100g or meq/100g. CEC is measured in moles of electric charge, so a cation-exchange capacity of 10 cmol c /kg could hold 10 cmol of Na + cations (with 1 unit of charge per cation) per kilogram of soil, but only 5 cmol Ca 2+ (2 units of charge per cation). [ 1 ]
The peroxide value is defined as the amount of peroxide oxygen per 1 kilogram of fat or oil. Traditionally this was expressed in units of milliequivalents, although in SI units the appropriate option would be in millimoles per kilogram (N.B. 1 milliequivalents = 0.5 millimole; because 1 mEq of O 2 =1 mmol/2 of O 2 =0.5 mmol of O 2, where 2 is valence).
This is especially common for measurement of compounds in biological fluids; for instance, the healthy level of potassium in the blood of a human is defined between 3.5 and 5.0 mEq/L. A certain amount of univalent ions provides the same amount of equivalents while the same amount of divalent ions provides twice the amount of equivalents.
Calcium, with an atomic weight 40 times that of hydrogen and with a valence of two, converts to (40 ÷ 2) × 1 milliequivalent = 20 milliequivalents of hydrogen ion per 100 grams of dry soil or 20 meq/100 g. [104] The modern measure of CEC is expressed as centimoles of positive charge per kilogram (cmol/kg) of oven-dry soil.
Mesotrophic soils are soils with a moderate inherent fertility.An indicator of soil fertility is its base status, which is expressed as a ratio relating the major nutrient cations (calcium, magnesium, potassium and sodium) found there to the soil's clay percentage.
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The cation-exchange capacity (CEC) of illite is smaller than that of smectite but higher than that of kaolinite, typically around 20 – 30 meq/100 g. Illite was first described for occurrences in the Maquoketa shale in Calhoun County, Illinois, US, in 1937. The name was derived from its type location in Illinois. [2]
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera). [13]