Process closed-loop experimental

This chapter has provided a brief overview of the application of optimal control theory to the control of molecular processes. It has addressed only the theoretical aspects and approaches to the topic and has not covered the many successful experimental applications [33, 37, 164-183], arising especially from the closed-loop approach of Rabitz [32]. The basic formulae have been presented and carefully derived in Section II and Appendix A, respectively. The theory required for application to photodissociation and unimolecular dissociation processes is also discussed in Section II, while the new equations needed in this connection are derived in Appendix B. An exciting related area of coherent control which has not been treated in this review is that of the control of bimolecular chemical reactions, in which both initial and final states are continuum scattering states [7, 14, 27-29, 184-188]. 

In regard dynamics and control scopes, the contributions address analysis of open and closed-loop systems, fault detection and the dynamical behavior of controlled processes. Concerning control design, the contributors have exploited fuzzy and neuro-fuzzy techniques for control design and fault detection. Moreover, robust approaches to dynamical output feedback from geometric control are also included. In addition, the contributors have also enclosed results concerning the dynamics of controlled processes, such as the study of homoclinic orbits in controlled CSTR and the experimental evidence of how feedback interconnection in a recycling bioreactor can induce unpredictable (possibly chaotic) oscillations. 

As the reaction is reversible, the catalytic process can be represented as a closed loop. The catalytic cycle of LDH is reduced to six snapshots here. Intermediate steps in catalysis such as those shown here are extremely short-lived and therefore dif cult to detect. Their existence was deduced indirectly from a large number of experimental findings—e.g., kinetic and binding measurements. 

A microcomputer (Digital Equipment Co. MINC 23 and VT105 CRT terminal) controls the experiment and processes the data (ID). The CL experimental variables, photon counts per second, sample temperature, stress, and strain, are monitored continuously by the computer and recorded at selected time intervals for closed-loop control of the CL experiment and subsequent off-line storage on flexible disk. 

Encouraged by the confirmation of the control concept, two-parameter control was considered in order to manipulate different processes in dimers and diatomic molecules. In addition to the pump-probe time delay, the second control parameter involved the pump [72, 73] or probe [66, 67] wavelength, the pump-dump delay [69, 74, 75], the laser power [121], the chirp [68, 76], or the temporal width [70] of the laser pulse. Optimal pump-dump control of K2 has been carried out theoretically in order to maximize the population of certain vibrational levels of the ground electronic state using one excited state as an intermediate pathway [71, 292-294]. The maximization of the ionization yield in mixed alkali dimers has been performed first experimentally using closed-loop learning control [77,78, 83] (CLL) and then theoretically in the framework of optimal control theory (OCT) [84]. 

Because the fabrication process is such an essential part of microfluidics, an overview of the principles underlying the microfabrication technology is presented. Pressure, flow, and temperature measurements are essential variables for characterizing fluid motion in any system. An important goal is the design and construction of self-contained microfluidic systems. Because of their small size, incorporation of pressure, flow, and temperature sensors directly on the microfluid system chip is highly desirable. There are relatively few examples where microfluidic systems have been constructed with these on-board sensors. There have been so many microsensor developments in recent years that it is only a matter of time before such systems will appear. Small-scale actuators to provide either open- or closed-loop control of the flow in microchannels are needed and these efforts are addressed. While experimental work on fluid flow itself in microscale structures is rather sparse, some results will be presented that emphasize the similarity and/or differences between macroscopic and microscopic flow of liquids. Although there are not many applications of... 

Like any closed-loop system, the behavior of the respiratory control system is defined by the continual interaction of the controller and the peripheral processes being controlled. The latter include the respiratory mechanical system and the pulmonary gas exchange process. These peripheral processes have been extensively studied, and their quantitative relationships have been described in detail in previous reviews. Less well understood is the behavior of the respiratory controller and the way in which it processes afferent inputs. A confounding factor is that the controller may manifest itself in many different ways, depending on the modeling and experimental approaches being taken. Traditionally, the respiratory control system has been modeled as a closed-loop feedback/feedforward regulator whereby homeostasis of arterial blood gas and pH is maintained. Alternatively, the respiratory controller may be viewed as a... 

An automated pilot-scale 1-litre experimental polymer reactor system with facilities for on-line measurement of flow rate, temperature and density has been set up by Chien and Penlidis (1994a, b). These authors describe a set of open-loop process identification experiments and closed-loop control experiments performed on this system where monomer conversion is controlled in the presence of reactive impurities using the initiator flow rate as the manipulated variable. 

In order to guarantee defined experimental conditions, the acoustic field was realized in a thermally insulated process chamber equipped with closed loop... 

If liquid water is a mixture of some components, it is natural to expect that at some conditions they may undergo liquid-liquid phase transition, similar to the one in the binary liquid mixtures. Contrary to the mixtures of chemically different compounds, concentrations of components in liquid water cannot be imposed independently on temperature and pressure. Besides, the universality class of the liquid-liquid critical points of one-component isotropic fluids may differ from the universality class of Ising model [6]. However, many other features should be similar in both cases. Even when the liquid-liquid transition is unachievable experimentally due to crystallization or due to other processes, its critical point may have a strong distant effect on the properties of liquid water at ambient conditions. In a two-component binary mixture, effect of both the liquid-vapor and the liquid-liquid critical points on fluid properties should be taken into account [62]. The liquid-liquid critical point may be distant in terms of temperature, pressure, and also external field , which may be varied by addition of impurities or by small variation in molecular structure (for example, by deuteration) [63, 64]. For example, mixture of 3-methylpyridine with heavy water possesses a closed-loop... 

INFICON s Auto Control Tune is based on measurements of the system response w/ith an open loop. The characteristic of the system response is calculated on the basis of a step change in the control signal. It is determined experimentally through two kinds of curve accordance at two points. This can be done either quickly w/ith a random rate or more precisely with a rate close to the desired setpoint. Since the process response depends on the position of the system (in our case the coating growth rate), it is best measured near the desired virork point. The process information measured in this vray (process amplification Kp, time constant T., and dead time L) are used to generate the most appropriate PID control parameters. 

---