Exit Function

Use the Exit Sub or Exit Function to exit from a procedure. Again, the Exit statement will normally be located within an If statement. 

If IsMissing(decimals) Then MolWt = FW Exit Function... 

If XSize <> rng(z).Rows.Count Then MakeArray = CVErr(xlErrRef) Exit Function YMax = YMax + YSize Next z... 

See also Exit, Function, If, Then, Else, Select Case, Sub, With Exit Command... 

Syntax Exit Do, Exit For, Exit Function, Exit Sub... 

The relation between the entrance function and that of the exit of some system is given by a so called Convolution Operation. This operation allows to determine the exit function s(t) when we know the entrance function e(t) and the impulse response h(t) (Fig. 4-12). 

A function analysis should start with function decomposition where we can see how a function is broken down from a higher abstraction level into a lower one. Figure 4.4 shows that three functions are illustrated on one system element. Level 2 shows that the functions ate composed of different sub functions and also of more than just one entrance or exit. Function 1 could be a normal brake function with two activations (foot- and handbrakes) as well as two actuators (front wheel and rear-wheel brake), function 2 could be a brake activation through a sensor (for example the radar of ACC) and function 3 would be a parking brake, which is accessed by the same operational unit (foot- and handbrakes). According to that the sub functions in the blue circle would be jointly used by different functions. 

The first requirement is a source of infrared radiation that emits all frequencies of the spectral range being studied. This polychromatic beam is analyzed by a monochromator, formerly a system of prisms, today diffraction gratings. The movement of the monochromator causes the spectrum from the source to scan across an exit slit onto the detector. This kind of spectrometer in which the range of wavelengths is swept as a function of time and monochromator movement is called the dispersive type. 

Flotation process kinetics determine the residence time, the average time a given particle stays in the flotation pulp from the instant it enters the ceU until it exits. One way to study flotation kinetics is to record flotation recoveries as a function of time under a given set of conditions such as pulp pH, coUector concentration, particle size, etc. The data allow the derivation of an expression that describes the rate of the process. 

Formation of Airborne Emissions. Airborne emissions are formed from combustion of waste fuels as a function of certain physical and chemical reactions and mechanisms. In grate-fired systems, particulate emissions result from particles being swept through the furnace and boiler in the gaseous combustion products, and from incomplete oxidation of the soHd particles, with consequent char carryover. If pile burning is used, eg, the mass bum units employed for unprocessed MSW, typically only 20—25% of the unbumed soHds and inerts exit the combustion system as flyash. If spreader-stoker technologies are employed, between 75 and 90% of the unbumed soHds and inerts may exit the combustion system in the form of flyash. 

Oxygen is suppHed quite routinely to patients suffering impaired respiratory function as weU as in other situations where oxygen is deemed to be useflil. The pure oxygen, with humidification, is deHvered via a simple double tube (cannula) to a point just inside the nostrils where the 99.5% gas blends with the room air (21% O2), and is inhaled. The concentration of oxygen that reaches the lungs thus depends on the rate and volume of air inhaled and on the exit flow of oxygen from the cannula, usually one to six L/min. 

Operational Characteristics. Oxygen generation from chlorate candles is exothermic and management of the heat released is a function of design of the total unit iato which the candle is iacorporated. Because of the low heat content of the evolved gas, the gas exit temperature usually is less than ca 93°C. Some of the heat is taken up within the candle mass by specific heat or heat of fusion of the sodium chloride. The reacted candle mass continues to evolve heat after reaction ends. The heat release duting reaction is primarily a function of the fuel type and content, but averages 3.7 MJ/m (100 Btu/fT) of evolved oxygen at STP for 4—8 wt % iron compositions. 

The carbon monoxide concentration of gas streams is a function of many parameters. In general, increased carbon monoxide concentration is found with an increase in the carbon-to-hydrogen ratio in the feed hydrocarbon a decrease in the steam-to-feed-carbon ratio increase in the synthesis gas exit temperature and avoidance of reequiUbration of the gas stream at a temperature lower than the synthesis temperature. Specific improvement in carbon monoxide production by steam reformers is made by recycling by-product carbon dioxide to the process feed inlet of the reformer (83,84). This increases the relative carbon-to-hydrogen ratio of the feed and raises the equiUbrium carbon monoxide concentration of the effluent. 

The calculations begin with given values for the independent variables u and exit with the (constrained) derivatives of the objective function with respec t to them. Use the routine described above for the unconstrained problem where a succession of quadratic fits is used to move toward the optimal point for an unconstrained problem. This approach is a form or the generahzed reduced gradient (GRG) approach to optimizing, one of the better ways to cany out optimization numerically. 

Though this is a quartic equation, it is capable of explicit solution because of the absence of second and third degree terms. Trial-and-error enters, however, because (GSi)r and are mild functions of Tg and related Te, respectively, and aprehminary guess of Tg is necessaiy. An ambiguity can exist in interpretation of terms. If part of the enclosure surface consists of screen tubes over the chamber-gas exit to a convection section, radiative transfer to those tubes is included in the chamber energy balance, but convection is not, because it has no effect on chamber gas temperature. 

Capacity Element Now consider the case where the valve in Fig. 8-7 is replaced with a pump. In this case, it is reasonable to assume that the exit flow from the tank is independent of the level in the tank. For such a case, Eq. (8-22) still holds, except that/i no longer depends on hi. For changes in fi, the transfer function relating changes in to changes in is shown in Fig. 8-10. This is an example of a pure capacity process, also called an integrating system. The cross sectional area of the tank is the chemical process equivalent of an electrical capacitor. If the inlet flow is step forced while the outlet is held... 

Unless material characteristics hmit the gas temperature, the inlet temperature is usually fixed by the heating medium employed i.e., 400 to 450 K for steam or 800 to 1100 K for gas- and oil-fired burners. The proper exit-gas temperature is largely an economic function. Its value may be determined as follows ... 

Figure (14-5) is a plot of Eq. (14-23) from which the value of Nog can be read directly as a function of mGM/LM and the ratio of concentrations. This plot and Eq. (14-23) are equivalent to the use of a logarithmic mean of terminal driving forces, but they are more convenient because one does not need to compute the exit-liquor concentration X. ... 

Although Eq. (14-31) is convenient for computing the composition of the exit gas as a function of the number of theoretical stages, an alternative equation derived by Colburn [Tran.s. Am. Jn.st. Chem. Eng., 35, 211 (1939)] is more useful when the number of theoretical plates is the unknown ... 

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