Dual-mode control

Recall the specifications which were set, forth at the beginning of the section on dual-mode control. 3 laximum speed has been provided by the on-off controller. The programmed switching critically damps the loop as the set point is approached. Offset is eliminated by reset iu the... 

Shinskey, F. G., and J. L Weinstein A Dual mode Control System for a Batch Exothermic Reactor, 20th Anmal ZSA Conf., October, 1965. 

The control strategies for dual mode hybrid vehicles are a combination of those used for series and parallel hybrids. There are so many possible hardware arrangements and associated control strategies, it is not possible to summarize them in a simple manner as was the case for series and parallel hybrids. The objective of the dual mode operation is to use the... 

Each heliostat is designed to illuminate a specific area on the parabola and is equipped with a dual optical control system, which maintains the proper orientation for each hcliostat by means of a dual hydraulic system. This dual system permits each heliostat lo be operated in either a search or track mode. In both cases, the optical guidance system uses an optical tube, which contains four photodiodes that control the heliostat motion in east-west and up-down direction. 

An important value of a permeation model is not simply its ability to correlate experimental data, but rather to provide a framework for understanding the principal factors controlling membrane performance. The dual mode model is derived from... 

Benomyl has been frequently reported to be more effective than MBC although both compounds exhibited similar toxic effect. Kdller et al. (1982) found that benomyl, but not MBC inhibits cutinase from Fusarium solani by the reaction of butylisocyanate and prevents under controlled conditions of a bioassay, the fungal penetration into its host suggesting the possibility of a dual mode of action for this fungicide. 

Lee, G., andGilman, M. (1994). Dual modes of control ofc-fos mRNA induction by intracellular calcium in T cells. Mol. Cell. Biol. 14, 4579-4587. 

FIGURE 2 Proposed dual mode for calmodulin (CaM) control of nitric oxide synthase (NOS) electron transfer. Neuronal NOS is composed of a reductase and an oxygenase domain, shown as two circles. CaM binding to NOS activates at two points in the electron transfer sequence (1) It increases the rate at which NADPH-derived electrons are transferred into the flavins, and (2) it enables the flavins to pass electrons to the oxygenase domain of NOS. Activation at the first point is associated with an increase in reductase domain-specific catalytic activities, such as electron transfer to cytochrome c or ferricyanide (FeCN ). Activation at the second point is associated with a reduction of NOS heme iron, an initiation of NO synthesis from L-arginine (Arg), or a reduction of Oj to form superoxide (O2) in the absence of substrate. FAD, Flavin-adenine dinucleotide FMN, flavin mononucleotide NO, nitric oxide. 

Yagi, S., M. Ezoe, I. Yonekma, T. Takagishi, and H. Nakazumi (2003). Diarylurea-linked zinc porphyrin dimer as a dual-mode artificial receptor Supramolecular control of complexation-faciUtated photoinduced electron transfer. J. Am. Chem. Soc. 125(14), 4068-4069. 

Scan is a technique where storage elements (latches and flip-flops) are changed to dual mode elements. For instance, Fig. 8.125 shows a normal flip-flop of an integrated chcuit. Also shown in Fig. 8.125 is a flip-flop converted to a scan register element. During normal operation, the D input and system clock control the output of the flip-flop. During scan operation, the scan clocks are used to control shifting of data into... 

Chromism may also be induced by two separate external stimuli. This is termed dual-mode photochromism [51], A particularly versatile example involves the flavylium system, the basic structure of anthocyanin dyes. With these, because of the complex acid-base behavior, interconversion between the various coloured species formed can be controlled by the dual application of light and pH changes [72]. It is possible in this way to have a pH gated photochromic system. 

The linear controller must, above all, be preloaded to the anticipated process conditions at the new set point. This was found to be advantageous whenever an antiwindup switch is used in the reset circuit. And because reset is normally required with a dual-mode arrangement, the control system must include an antiwindup switch into which the preload setting is introduced. The arrangement of the system for increasing set-point changes is shown in Fig. 5.17. 

It has been demonstrated that a loop whose gain varies inversely with amplitude is prone to limit-cycle. Any controller with similar characteristics can promote limit cycling in an otherwise linear loop. On-off controllers are in this categoiy. So any nonlinear device that is purpose inserted into a loop for the sake of engendering stability must have the opposite characteristic gain increasing with amplitude. The only stabilizing nonlinear devices discussed up to this point have this property -it was manifested as a dead zone in the three-state controller and as the linear mode in the dual mode system. 

It is possible to create a controller with a continuous nonlinear function whose gain increases with amplitude. In contrast to the three-state controller, its gain in the region of zero error would be greater than zero, with integrating action to avoid offset. But its change in gain with amplitude should be less severe than that of a dual-mode system. Thus it would be more tolerant of inaccuracy in the control parameters. 

A batch chemical reactor is to be brought up to operating temperature with a dual-mode system. Full controller output supplies heat through a hot-water valve, while zero output opens a cold-mater valve fully at 50 percent output, both valves are closed. While full heating is applied, the temperature of the batch rises at, IT/min the time constant of the jacket is estimated at 3 min, and the total dead time of the system is 2 min. The normal load is equivalent to 30 percent, of controller output. Estimate the required values for the three adjustments in the optimal switching program. 

The conceptual design of CLEAR-I was completed in 2013, and engineering design is underway. CLEAR-I has a subcritical and critical dual-mode operation. Key components of CLEAR-I, including the control rod drive mechanism, refueling system, FA, and a simulator for principle verification, have been fabricated and tested. Fig. 6.6 and Table 6.9 provide a sketch and summary of the key parameters of CLEAR-1. 

The diffusion-controlled limiting current at 1AM operating in dual mode is given by Eq. (20.10) "... 

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