Polymer composition feedback controller

Polymer composition feedback controller, which updates the set points for the reactor monomer feed composition based on the laboratory analysis of a reactor sample. This controller thus provides the necessary integral action so that the offset between the measured composition of the reactor sample and the polymer grade composition is minimized. 

Mallavarapu K, Newbury K, Leo D (2001) Feedback control of the bending response of ionic polymer-metal composite actuators. SPIE Proc 4329 301-310. doi 10.1117/12.432660... 

Hunt, A., Chen, Z., Tan, X. and Kruusmaa, M. (2009). Feedback control of a coupled IPMC (ionic polymer-metal composite) sensor-actuator, in Proceedings of the ASME 2009 Dynamic Systems and Control Conference (Hollywood, CA). 

Ultrasonic measurements have also proven useful in the characterization of polymer melts (see Section 4.3.3.1). The ultrasonic transit time ( Laufzeit ) is dependent on the elastic properties of the material, pressure, temperature, chemical composition, and structure. It has been found [37] that the ultrasonic transit time is a sensitive measure of the condition of the polymer melt, in particular melt homogeneity. In a process control system, the ultrasonic transit time can provide a more useful feedback control signal than a single melt temperature measurement. 

The combination of feedforward and feedback control provides a very powerful practical strategy for the control of polymer properties such as composition and molecular weight. Typically it is still fairly difficult to have on-line direct measurements of polymer composition, so the control design has to incorporate the avail-... 

In the design of the composition and viscosity feedback controllers it is very important to establish whether the polymer reactor dynamics need to be taken explicitly into account. The choice of sampling frequency balances the requirements for good quality control versus the need to minimize analytical costs. Usually, when the reactor residence time is much shorter than the sampling frequency, integral control is appropriate, because the time between measurements is usually sufficient for the effect of an adjustment to a process variable set point to be com-... 

In general, the optimization of polymerization processes [2] focuses on the determination of trade-offs between polydispersity, particle size, polymer composition, number average molar mass, and reaction time with reactor temperature and reactant flow rates as manipulated variables. Certain approaches [3] apply nonhnear model predictive control and online, nonlinear, inferential feedback control [4] to both continuous and semibatch emulsion polymerization. The objectives include the control of copolymer composition. 

At steady state, continuous polymerization reactors produce the polymers of constant properties. In reality, however, the reactor is subject to some external disturbances such as variations in feed composition, feed temperature, and cooling water source temperature. Therefore, accurate feedback control of the reactor is required to maintain consistent product quality and reactor... 

Little is known regarding the regulation of the levels of GDP-mannose and GDP-fucose in animal tissues, but it is of interest to note that microorganisms which contain polymer-bound mannose or fucose, or both, have diflFerent feedback inhibition patterns depending on the composition of the polysaccharides (Komfeld and Ginsburg, 1965, 1966). These mechanisms permit independent control of the rates of synthesis of the two nucleotide sugars. 

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