Process variables control

N. Hofmann, S. Olive, G. Laschet, F. Hediger, J. Wolf, P. R. Sahm. Numerical optimization of process control variables for the Bridgman casting process. Model Simula Mater Sci Eng 5 23, 1997. 

Stopping excursions from normal operation conditions before they become hazardous, by correction of process control variables when dangerous situations are detected on-line detection of process deviations associated with trip systems for corrective actions. 

Equation (5) is equivalent to stating that sublimation and subsequent transport of 1 g of water vapor into the chamber demands a heat input of 650 cal (2720 J) from the shelves. The vial heat transfer coefficient, Kv, depends upon the chamber pressure, Pc and the vapor pressure of ice, P0, depends in exponential fashion upon the product temperature, Tp. With a knowledge of the mass transfer coefficients, Rp and Rs, and the vial heat transfer coefficient, Kv, specification of the process control parameters, Pc and 7 , allows Eq. (5) to be solved for the product temperature, Tp. The product temperature, and therefore P0, are obviously determined by a number of factors, including the nature of the product and the extent of prior drying (i.e., the cake thickness) through Rp, the nature of the container through Kv, and the process control variables Pc and Ts. With the product temperature calculated, the sublimation rate is determined by Eq. (4). 

The process control display is divided into three sections. Six process control variable displays are shown at the top of the screen. Variable displays reflect the most recent measurements of the particulate. A time... 

In turn, the rates L and V will adjust to the pressure difference maintained across the membrane, which is also related to the membrane permeability. If a higher permeate rate is desired, then the pressure Py must be lowered and/or the feed rate F increased. (Alternately, albeit it is not a process control variable, the membrane surface or size can be increased.) It should be emphasized, moreover, that the calculations are process design estimations, prior to fabrication and operation. 

Figure 1, Building blocks of the particulate transport model representing the most important physical and chemical processes. Control variables and interrelationships are indicated.

One FSW control algorithm approach monitors the periodic fluctuation in the global process forces and torques and adjusts the system parameters as necessary to maintain the proper temperature and metal flow to prevent volumetric defect formation. Several analytical methods to evaluate weld quality directly from process control variables and system torque and force responses have been investigated (Ref... 

Bifano, T.G. and Fawcett, S.C., Specific grinding energy as an in process control variable for ductile-regime grinding, Prec Engg, 13, 4 (1991) 256. 

Calibrate critical process control variables on a regular basis. Where applicable and practicable, provide banana jacks/switches or accessible quick disconnects to allow convenient access for calibration. Discuss calibration requirements with the Electrical Engineer or an Instrument Mechanic. A calibration label shall be affixed to the device (or in close proximity), indicating the equipment I.D., calibration date, calibrator, and calibration due date. 

Electrospinning parameters are the variables which can be controlled and adjusted in order to manipulate the morphology and feamres of the electrospun nanofibers. Electrospinning parameters are classified into three main categories which are (i) processing (controlled) variables, (ii) ambient (uncontrolled) variables, and (iii) the solution variables (Huang et al. 2003 Pham et al. 2006 Zander 2013). Electrospinning parameters are summarized in Table 1. 

FIGURE A.2 Process control variables for injection molding. 

Table 8.6. Fluoropolymer Extrusion Process Control Variables...

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