On-line operations

According to Ref. 6, 70 incidents of corrosion damage for 1000 km of buried steel pipeline transporting gas were reported on average each year in Germany. For 1000 km of pipeline on lines operating at pressures up to 4 bar, 100 incidents of... 

Figure 8.18 Schematic diagrams showing (a) serially connected multilayer OPLC employing different types of stationaiy phase of decreasing polarity (A > B > C) as a type of MD-FFPC (b) fully off-line operational mode (c) fully on-line operational mode.

Methods developed for on-line technological control have to be tested for the variation of the product composition due to process variations. However, if rugged analytical procedures are developed these multidimensional methods may only require minimal attention during on-line operation. Multidimensional chromatography for the analysis of complex polymer and industrial samples offers chromatogra-phers high productivity and efficiency and is an excellent alternative to off-line methods. 

The automotive industry favours sets of parts assembled by the plastic furnisher and including non-plastic elements such as metal components, electronics. .. This simplifies purchasing and on-line operations. For example, a seat module includes the frame, cushioning, slide system, position control device. .. 

Thoma H, Hutzinger O. 1987. Pyrolysis and GC/MS-analysis of brominated flame retardants in on-line operation. Chemosphere 16(6) 1353-1360. 

Third, the methodology is ideally suited to automation and on-line operations, so much more will occur in the future clinical chemists responsible for drug analyses are already committed to automation. 

Electrolytic (coukxnetric) hygrometers The quantity of electricity required to carry out a chemical reaction is measured. The principle is based upon Faraday s law of electrolysis. Water is absorbed on to a thin film of dessicant (e.g. P2O5) and electrolysed. The current required for the electrolysis varies according to the amount of water vapour absorbed. The current depends also upon the flowrate. Capable of high precision. Used in the range 1000 to 3000 ppm of water by volume. Somewhat complicated procedure. Recombination of products to water is necessary after electrolysis. Density, pressure and flowrates have to be maintained precisely. Contamination can poison the cell. It is ideal for binary mixtures but is of limited range. Suitable for on-line operation. 

The light transmission technique is most frequently used for the determination of average bubble size in gas-liquid dispersion. It has the advantages of quick measurement and on-line operation. The probes are usually made of mirror-treated glass rods (Vermeulen et al., 1955), internally blackened tubes with mirrors (Calderbank, 1958), or fiber optic light guide (Hong and Lee, 1983). 

Operations that are conducted while the RO system is off line are just as important as on-line operations in keeping an RO system functioning well. Off-line operations covered in this chapter include system flush, membrane cleaning, and membrane lay-up. 

The central constraint in designing for on-line operation was the maintenance of the integrity of the method chemistry. To be commercially attractive, the system would also have to be as reliably free of maintenance as possible, including calibration, so reagent stability and/or purification would need to be addressed. 

Let us describe the principles and on-line operation of program "SEP-Search", developed and checked in the Emilio Segre Observatory of Israel Cosmic Ray Space Weather Center. The determination of increasing flux is made by comparison with intensity averaged from 120 to 61 minutes before the present Z-th one-minute data. The program for each Z-th minute determines the values... 

In large-scale work, particularly in the petroleum industry, considerable use is made of continuous methods for riscmUy determination. Such a method might conceivably be modified for distillation on a laboratory scale. Fritzsche [71] has given a survey of visco.simeters for continuous on-line operation in oil refineries. 

In fouling services where on-line operation must be continuously maintained, the reboiler is frequently spared to facilitate cleaning while the column is on-line. An extensive discussion on decommissioning, cleaning, and recommissioning a reboiler while the column is online is described elsewhere (279). 

Two other computer facilities are a data collection system which monitors remotely located data acquisition and experiment-control computers via asynchronous serial lines and the two Evans and Sutherland LDS-1 interactive graphics terminals. A PDP 10 included in the network configuration as an alternate file transport concentrator and auxiliary network development machine also performs the role of worker computer with the Evans and Sutherland display equipment. Other subnetworks have been designed for inclusion in the Octopus network to direct the on-line operation of LLL high-speed printer and microfilm recorder output facilities, to administer a second, expanded television monitor system providing 256 channels of video input for distribution to 512 additional monitors, and to control a CDC on-line tape library of 8.7 x 10 bits scheduled for delivery in 1975. The Computer Hardcopy Output Recording System (CHORS) concentrators are two Modcomp II computers, and TMDS-II will utilize two PDP 11/45s both subnetworks are to become operational during the... 

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