Distributed control system background

Instead of the above-cited control chart to test the hypothesis that the measured values are randomly distributed, a tolerance chart may be established to compare periodic measurements with established acceptance limits (see ANSI N42.2, Appendix A). In this system, an acceptable relative standard deviation—say 2% for the standard source count and 10% for background count— is selected and horizontal lines that represent these values are drawn as upper and lower acceptance limits. These limits should be wider than the statistically based limits if they were narrower, they would be exceeded frequently. They need not be symmetrical on the positive and negative side. Their purpose is to keep the counting efficiency and background count rate within limits that give acceptable results even if the instrument and its output are subject to nonrandom fluctuations. 

The topic of handling liquids of different viscosities for dispersion processes in microfluidic networks with two microreactors ( droplet emitters ) is addressed by Unilever R D (Vlaardingen, The Netherlands) in a patent [14,15]. The patent deals with the flow distribution in a microfluidic network on the background of dispersion processes with two supply sources for the two phases, which supply via upstream channel systems two microfluidic reactors called drop emitters (Figure 22.6). The dispersion leaves the microreactors via downstream channels. The major point of the patent is that the flow distribution is controlled by a design which creates a high pressure drop in the upstream channels. The pressure drop in the downstream... 

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