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A weighting curve is a graph of a set of factors, that are used to 'weight' measured values of a variable according to their importance in relation to some outcome. An important example is frequency weighting in sound level measurement where a specific set of weighting curves known as A-, B-, C-, and D-weighting as defined in IEC 61672 [1] are used.
This led to the CCIR-468 standard which defined a new weighting curve and quasi-peak rectifier. The origin of the current ITU-R 468 weighting curve can be traced to 1956. The 1968 BBC EL-17 report discusses several weighting curves, including one identified as D.P.B. which was chosen as superior to the alternatives: A.S.A, C.C.I.F and O.I.R.T ...
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
The source and sink composite curves is a graphical tool for setting water recovery targets as well as for design of water recovery networks. [5] A 2018 study found by water pinch and water footprint analysis that for bricks with typical materials of clay and shale, the water consumption footprint was 2.02 L of water per brick. [6]
h f = head loss in meters (water) over the length of pipe; L = length of pipe in meters; Q = volumetric flow rate, m 3 /s (cubic meters per second) C = pipe roughness coefficient; d = inside pipe diameter, m (meters) Note: pressure drop can be computed from head loss as h f × the unit weight of water (e.g., 9810 N/m 3 at 4 deg C)
A commonly used weighting is the A-weighting curve, which results in units of dBA sound pressure level. Because the frequency response of human hearing varies with loudness, the A-weighting curve is correct only at a level of 40- phon and other curves known as B- , C- and D-weighting are also used, the latter being particularly intended for the ...
A simplified version of the definition is: The k v factor of a valve indicates "The water flow in m 3 /h, at a pressure drop across the valve of 1 kgf/cm 2 when the valve is completely open. The complete definition also says that the flow medium must have a density of 1000 kg/m 3 and a kinematic viscosity of 10 −6 m 2 /s, e.g. water. [clarify]
Gradually varied flow occurs when the change in flow depth per change in flow distance is very small. In this case, hydrostatic relationships developed for uniform flow still apply. Examples of this include the backwater behind an in-stream structure (e.g. dam, sluice gate, weir, etc.), when there is a constriction in the channel, and when ...