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Functionally, the hilar valve allows water vapor to enter or exit to ensure viability, while blocking liquid water. If however, humidity levels gradually rise to a high enough level, the hilar valve remains open, allowing liquid water passage for germination. [17] Physiologically, the inner and outer epidermides have independent hilar valve ...
Sodium hydroxide, also known as lye and caustic soda, [1] [2] is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na + and hydroxide anions OH −. Sodium hydroxide is a highly corrosive base and alkali that decomposes lipids and proteins at ambient temperatures and may cause severe ...
The following compounds are liquid at room temperature and are completely miscible with water; they are often used as solvents. Many of them are hygroscopic . Organic compounds
An electric multi-turn actuator on a gate valve. A gate valve, also known as a sluice valve, is a valve that opens by lifting a barrier (gate) out of the path of the fluid. Gate valves require very little space along the pipe axis and hardly restrict the flow of fluid when the gate is fully opened.
Alkali hydroxides are formed in the reaction between alkali metals and water. A typical school demonstration demonstrates what happens when a piece of an alkali metal is introduced to a bowl of water. A vigorous reaction occurs, producing hydrogen gas and the specific alkali hydroxide. For example, if sodium is the alkali metal:
Larner–Johnson Valve: needle control valve often in large sizes used in water supply systems; Leaf valve: one-way valve consisting of a diagonal obstruction with an opening covered by a hinged flap; Line blind valve: a thin sheet oriented perpendicular to the pipe. The sheet has a solid end and a flow-through end; sliding it from one position ...
Without the presence of dissolved NaOH or KOH, responsible for the high pH (~13.5) of the concrete pore water, the amorphous silica of the reactive aggregates would not be dissolved and the reaction would not evolve. Moreover, the soluble sodium or potassium silicate is very hygroscopic and swells when it absorbs water.
Within the gate valve, there is a gatelike disk that moves up and down perpendicular to the path of flow and seats against two seat faces to shut off flow. The velocity of the fluid against a partly opened disk may cause vibration and chattering which will ultimately lead to damage to the seating surfaces. This is a common way that gate valves ...