Separation system, conventional source

Describing the behavior of undefined mixtures, whether from natural or synthetic sources, often begins with the separation of these complex systems into effective pseudocomponents by distillation (1 ). Each pseudocomponent is then characterized as if it were a pure compound, and its characterization data are used in appropriate correlations. The presence of nonvolatile residuum poses a serious limitation to such methodology. For coal-derived liquids, heavy crude oils, tar sands, and shale oil, more than 50 percent of the fluid may not be distillable (JL). Since this nonvolatile residue cannot be separated using conventional techniques, new methods of separation and characterization must be developed to provide the necessary information for design and operation of plants utilizing the fossil fuels mentioned above (2). 

Figure 2. Conventional source-separation system—Davis, California...

Visible and UV spectrophotometers are by far the most frequently used type of detectors in FI systems. This is also true for FI separation systems. Provided the light source intensity is strong enough, a conventional batch spectrophotometer can easily be converted into a flow-through spectrophotometer by substituting the conventional cuvette with a flow-through cell. 

An important issue to address is matching the flow rates of separation systems and ion sources. Conventional LC systems operate at high flow rates (milliliters per minute)... 

Figure 12.19 Schematic diagrams of two implementations of ALD. (a) Implementation in an essentially normal CVD reactor where pulses of gas of three types flow through the reactor, two reactive species responsible for deposition of the film and a purge gas that separates the two source gases from each other. The purge gas may also flow eontinuously and the other reactants can be introduced into this stream periodieally. (b) A system based on rotation of substrates through different source gases eontained in separate portions of the ehamber. In the example shown one source might be fiom a typieal CVD type reaetor while a seeond source gas might be supplied by a conventional MBE type evaporation source.

It is worth noting that some of these methods are both an inlet system to the mass spectrometer and an ion source at the same time and are not used with conventional ion sources. Thus, with electrospray, the process of removing the liquid phase from the column eluant also produces ions of any emerging mixture components, and these are passed straight to the mass spectrometer analyzer no separate ion source is needed. The particle beam method is different in that the liquid phase is removed, and any residual mixture components are passed into a conventional ion source (often electron ionization). 

Table IV shows X-ray data (55) on the homogeneity of Pd-Ag films prepared by simultaneous evaporation from separate sources, either in conventional vacuum or in UHV, with the substrate maintained at 0°C. The second group of films was prepared using a stainless steel system incorporating a large (100 1/sec) getter-ion pump, sorption trap, etc., but deposited inside a glass vessel. By the tests of homogeneity adopted, alloy films evaporated in conventional vacuum were not satisfactory, i.e., the lattice constants were generally outside the limits of the experimental error, 0.004 A, and the X-ray line profiles were not always symmetrical. In contrast, alloy films evaporated in UHV were satisfactorily homogeneous. Further, electron micrographs showed that these latter films were reasonably unsintered and thus, this method provides clean Pd-Ag alloy films with the required characteristics for surface studies.

The distribution system of an ICES is the same as that of a conventional district heating system. Each ICES has warm water supply and cool water return mains. Systems that supply both heating and cooling at the same time may have independent distribution systems for hot and cold water. Distributed systems using groundwater as a heat source may have only a distribution water supply line. Cascaded and distributed ICESs have separate heating distribution systems for each building. 

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