Datum plane

Next, we align all logs at the datum plane which now becomes a straight horizontal line. Note that by doing so we ignore all structural movements to which the sequence has been exposed. 

We can now correlate all events below or above the datum plane by comparing the log response. In many instances correlations are ambiguous. Where two or more correlation... 

The measurement of level can be defined as the determination of the location of the interface between two fluids, separable by gravity, with respecl to a fixed datum plane. The most common level measurement is that of the interface between a liquid and a gas. Other level mea-... 

If a reference datum plane (h = 0) is set at the bottom of each of the capillaries shown in the previous Fig. 5.5, the expression for the total driving force, that is the piezometric pressure difference along the penetration length h for a capillary with an upward (I pgh cos a) or a downward (—pgh cos a) orientation, can be represented by following equation (Bouchon and Pyle, 2005b),... 

BENTONITE. The term applied to alteied fine-grained volcanic ashes which have been blown considerable distance from their origin and deposited m marine waters. The resulting material is usually a white, but sometimes a colored, clay-like sediment which may contain bits of volcanic glass but is composed mainly of colloidal silica which will absorb large quantities of water. Since bentonites are wind-blown deposits they are useful as definite datum planes in stratigraphy, especially in helping to determine the contemporaneity of the different facies of marine sediments. 

The potential energy of a particle of fluid is measured by its elevation above any arbitrary datum plane. We are usually interested only in differences of elevation, and therefore the location of the datum plane is determined solely by convenience. 

Choose a datum plane through any convenient point. 

At point 3 there are both an unknown pressure and an unknown velocity hence the energy equation is not sufficient, as one equation is capable of determining only one unknown. The following procedure should then be used The datum plane may be taken at any level, but it is usually desirable to take it at the lowest point in the system and thus avoid negative values of z. Let the datum plane be assumed through point 5. At point 1 on the surface of the water the pressure is atmospheric, which is also the case with the stream at point 5. Thus, whatever the barometer pressure may be, it cancels... 

Hackett s results apply to the initial stages of ascent through granular media. With increasing time, the rate of advance diminishes and fails to follow the linear relation of Eq (15-14). Hackett attempted to explain the slow rise by constant readjustment of his datum plane, but failed to give any consistent or general theory. 

Z = vertical distance above an arbitrarily chosen datum plane, ft v = specific volume of the fluid ft3/lbm p = absolute pressure, lbf/ft2 Vt = instantaneous or point velocity, ft/s u = internal energy, ft 1 lbf/lbm... 

Z = vertical distance above an arbitrarily chosen datum plane, ft Greek Symbols... 

W = meehanical work imparted to the fluid system from an outside source, ft Ibf/lbm = weight of vessel, Ibm, see Table 6 Z = vertieal distance above an arbitrarily chosen datum plane, ft... 

The material balance from Problem 3-6 and either ASPEN PLUS or CHEMCAD-III computer software is used to develop the energy balance around each piece of equipment in the ethylene separation section. For example, around distillation column, C-601, the computer program establishes the heat content 6f streams 533, 602, and 603 above a selected datum plane. The distillation calculation indicates the flow rates of the oveiiiead and bottoms streams. The reflux and reboil then indicate the flow rates of the streams that are returned to the column and permits evaluation of the condenser and reboiler duties. In kW " this pan be expressed as... 

The enthalpy content in kW of each stream based on a fixed datum plane is given below... 

Work, J, ergs, or ft-lb - W, work delivered by system during cycle Mole fraction in gas mixture y, mole fraction of component A yg, mole fraction of component B mole fraction of component C Height above datum plane, m, cm, or ft Compressibility factor, dimensionless... 

Use Eq. (4.32). Take station a at the surface of the liquid in the tank and station b at the discharge end of the 2-in, pipe. Take the datum plane for elevations through the station a. Since the pressure at both stations is atmospheric, p — p. The velocity at station a is negligible because of the large diameter of the tank in comparison with that of the pipe. For turbulent flows the kinetic-energy factor a can be taken as 1.0 with negligible error. Equation (4.32) becomes... 

Wp Pump work per unit mass of fluid, J/g or ft-lby/lb Z Height above datum plane, m or ft Z , at station a Zj, at station b... 

If the system is adiabatic, 8q = 0 if no shaft work is done, SW, = 0 if the kinetic energy effects are negligible, d(U I2gc) = 0 and, if the elevation above the datum plane is constant, dZ = 0. Hence only the enthalpy term remains... 

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