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Pump-control scheme

As an initial (demonstration) application of the Icon/1000 control system, we automated two simultaneous acrylic lab polymerizations. In this application, heaters, agitators, and metering pumps are controlled. A batch proceeds automatically from state to state unless the operator intervenes through one of a series of color CRT touch screens allowing him to take complete manual control of the batch for as long as he desires. All important process variables are continually monitored and recorded. The entire control scheme was created, tested, and modified several times in the space of two months, without formal instruction, by a chemical engineer with little previous programming experience and no previous experience at all with this system. [Pg.475]

The second example is the quadratically chirped pump-dump scheme. Since the pioneering work by Tannor and Rice [119], the pump-dump method has been widely used to control various processes. However, since it is not possible to transfer a wave packet from one potential energy surface to another nearly completely by using the ordinary transform limited or linear chirped pulses, the... [Pg.166]

Example 1.3. Our third example illustrates a typical control scheme for an entire simple chemical plant. Figure 1.5 gives a simple schematic sketch of the process configuration and its control system. Two liquid feeds are pumped into a reactor in which they react to form products. The reaction is exothermic, and therefore heat must be removed from the reactor. This is accomplished by adding cooling water to a jacket surrounding the reactor. Reactor elHuent is pumped through a preheater into a distillation column that splits it into two product streams. [Pg.5]

Potter et al. were the first to apply this pump and control scheme to a... [Pg.57]

The control scheme shown in Fig. 17.4 is certainly quite common. But is it the best Figure 17.5 is a copy of the crude charge system in a now-defunct refinery in Port Arthur, Texas. I saw it in operation many years ago. It worked fine. The required flow of crude directly controls the governor. The turbine speed is then always at its optimum. The AP across the process-control valve is always zero, because there is no process-control valve. This design is a direct descendant of the original method of controlling the steam flow to pumps. The steam inlet valve was opened by the operator, so that the desired discharge flow was produced. [Pg.211]

Figure 3.24 shows control schemes for rotary and reciprocating compressors. Vacuum pumps are compressors operating between a low suction pressure and a fixed discharge pressure, usually... [Pg.60]

FIGURE 13 A pump-dump control scheme, used to control the branching ratio of the dissociation of a triatomic molecule, ABC. [Pg.157]

An intuitive method for controlling the motion of a wave packet is to use a pair of pump-probe laser pulses, as shown in Fig. 13. This method is called the pump-dump control scenario, in which the probe is a controlling pulse that is used to create a desired product of a chemical reaction. The controlling pulse is applied to the system just at the time when the wave packet on the excited state potential energy surface has propagated to the position of the desired reaction product on the ground state surface. In this scenario the control parameter is the delay time r. This type of control scheme is sometimes referred to as the Tannor-Rice model. [Pg.157]

The simple control scheme in Figure 2.103 measures the temperature difference (ATC-1) between the solar collector temperature and the solar water tank temperature, starts the water pump when AT > 20°C, and stops it when this temperature difference drops to 10°C. The variable-speed refrigerant pump circulation is similarly controlled. Because the condenser (lake, well, or swamp) temperature is more or less constant, AT control might not be essential and measuring only the evaporator (solar water tank temperature) by a standard thermostat (TC-2) can be sufficient. In this configuration, the refrigerant pump is started whenever the solar tank temperature is above 60°C (140°F), and the pump speed is increased to its maximum, as the temperature in the solar hot water tank reaches, say, 70°C (160°F). [Pg.310]

The remainder of this paper is organized as follows In Sect. 5.2, we present the basic theory of the present control scheme. The validity of the theoretical method and the choice of optimal pulse parameters are discussed in Sect. 5.3. In Sect. 5.4 we provide several numerical examples i) complete electronic excitation of the wavepacket from a nonequilibrium displaced position, taking LiH and NaK as examples ii) pump-dump and creation of localized target wavepackets on the ground electronic state potential, using NaK as an example, and iii) bond-selective photodissociation in the two-dimensional model of H2O. A localized wavepacket is made to jump to the excited-state potential in a desirable force-selective region so that it can be dissociated into the desirable channel. Future perspectives from the author s point of view are summarized in Sect. 5.5. [Pg.97]

Figure 3.21 (a) Schematic diagram of a pump-dump scheme to control the mod... [Pg.70]

The pump-dump scheme described above has also been applied to the control off the... [Pg.74]

A control mechanism has been proposed on the basis of the joint analysis of the experimental and theoretical information. The control scheme leading selectively to the formation of CpMn(CO)3+ is represented in Figure 6(b). The experiment realized with an optimal laser field is simulated by one pump pulse (at 3.49 eV) followed by a probe pulse (at 4.716eV) designed with the adequate properties of phase, frequency, and duration. Within these specific conditions, the quasi-bound state c A is populated selectively and the CO dissociation... [Pg.3820]


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See also in sourсe #XX -- [ Pg.91 ]




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