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The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt): If the ...
The AASHTO Soil Classification System was developed by the American Association of State Highway and Transportation Officials, and is used as a guide for the classification of soils and soil-aggregate mixtures for highway construction purposes. The classification system was first developed by Hogentogler and Terzaghi in 1929, [1] but has been ...
Soil texture. Soil texture is a classification instrument used both in the field and laboratory to determine soil classes based on their physical texture. Soil texture can be determined using qualitative methods such as texture by feel, and quantitative methods such as the hydrometer method based on Stokes' law.
Topsoil is composed of mineral particles and organic matter and usually extends to a depth of 5-10 inches (13–25 cm). Together these make a substrate capable of holding water and air which encourages biological activity. There are generally a high concentration of roots in topsoil since this is where plants obtain most of their vital nutrients.
A taxonomy is an arrangement in a systematic manner; the USDA soil taxonomy has six levels of classification. They are, from most general to specific: order, suborder, great group, subgroup, family and series. Soil properties that can be measured quantitatively are used in this classification system – they include: depth, moisture ...
Cation-exchange capacity is defined as the amount of positive charge that can be exchanged per mass of soil, usually measured in cmol c /kg. 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 ...
Net register tonnage (NRT, nrt, n.r.t.) is a ship's cargo volume capacity expressed in "register tons", one of which equals to a volume of 100 cubic feet (2.83 m 3).It is calculated by subtracting non-revenue-earning spaces i.e. spaces not available for carrying cargo, for example engine rooms, fuel tanks and crew quarters, from the ship's gross register tonnage.
Used mainly to determine the minimum water depth for safe passage of a vessel and to calculate the vessels displacement (obtained from ships stability tables) so as to determine the mass of cargo on board. Draft, Air – Air Draft/Draught is the distance from the water line to the highest point on a ship (including antennas) while it is loaded ...