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Frost resistance is the ability of plants to survive cold temperatures. Generally, land plants of the northern hemisphere have higher frost resistance than those of the southern hemisphere . [ 1 ]
Energy required to move a unit charge through an electric field from a reference point volt (V = J/C) L 2 M T −3 I −1: extensive, scalar Electrical resistance: R: Electric potential per unit electric current ohm (Ω = V/A) L 2 M T −3 I −2: extensive, scalar, assumes linearity Electrical resistivity: ρ e: Bulk property equivalent of ...
So that practical clothing may be described conveniently by a range of small integers, the unit of thermal resistance, to be called the “tog”, is the resistance that will maintain a temperature difference of 0.1°C. with a flux of 1 watt per square metre, or in more practical terms, 10°C. with a flux of 1 watt per square decimetre.
The chilling requirement of a fruit is the minimum period of cold weather after which a fruit-bearing tree will blossom.It is often expressed in chill hours, which can be calculated in different ways, all of which essentially involve adding up the total amount of time in a winter spent at certain temperatures.
Black frost (or "killing frost") is not strictly speaking frost at all, because it is the condition seen in crops when the humidity is too low for frost to form, but the temperature falls so low that plant tissues freeze and die, becoming blackened, hence the term "black frost".
γ w is the unit weight of water; G s is the specific gravity of the solid; e is the void ratio [3] Submerged unit weight The difference between the saturated unit weight and the unit weight of water. [4] It is often used in the calculation of the effective stress in a soil. The formula for submerged unit weight is: ′ = where γ′ is the ...
The frost line—also known as frost depth or freezing depth—is most commonly the depth to which the groundwater in soil is expected to freeze. The frost depth depends on the climatic conditions of an area, the heat transfer properties of the soil and adjacent materials, and on nearby heat sources.
The resistance to vertical flow (R i) of the i th soil layer with a saturated thickness d i and vertical hydraulic conductivity K v i is: = Expressing K v i in m/day and d i in m, the resistance (R i) is expressed in days. The total resistance (R t) of the aquifer is the sum of each layer's resistance: [8]