CMAS diagrams

CMAS diagrams The components of the CMAS system (CaO-MgO-Al203-Si02) comprise aibout 70-85 wt % of most basalts and more than 90 wt % of most mantle peridodtes. For this reason the CMAS system is used by experimental petrologists as a simplified analogue of more complex basalt and mantle systems. The CMAS projecdon... 

These modes of operation ate used in conjunction with the two most popular energy analyzers, the cylindrical mirror analyzer (CMA) and the concentric hemispherical analyzer (CHA). The most common form of the CMA used today is the double-pass version diagramed in Eigute 21. This device consists of two perfectly coaxial cylinders of radii r and r. The outer cylinder is held at a potential of (— ) and the inner cylinder is held at ground. The... 

Fig. 2. Schematic diagram of a high resolution He time-of-flight spectrometer. N-nozzle beam source, SI, 2-skimmers, Al-5 - apertures, T - sample, G - gas doser, CMA - Auger Spectrometer, IG - ion gun, L - LEED, C -magnetically suspended pseudorandom chopper, QMA-detector, quadrupole mass analyzer with channeltron.

Figure 4.2 Cross-cut through a CMA which accepts electrons into a cone set by the average polar angle 90 with angular spread A9 (not shown). Since the analyser accepts the full 2ji range of the azimuthal angle it is called a 2n-analyser. The diagram shows the principal ray from the source Q to the image B. The characteristic dimensions are the radii of the inner and outer cylinders, R-, and R and the total distance zsp between Q and B. The spectrometer voltage Usp is applied between the outer and inner cylinders and produces...

Figure 4.4 Imaging property of a CMA as introduced in Fig. 4.2. The diagram shows the principal ray (solid curve with cone angle 0) together with a finite bundle of electrons (dashed curves) accepted by the entrance slit Sj. All electrons have the same kinetic energy fi in, and the spectrometer voltage U°p is selected such that these electrons are imaged from the source point Q to the focal point B.

A schematic diagram of instrumentation used for ISS is shown in Fig. 14.36. This instrument is based on a CMA, discussed in Section 14.2.1.1. The instrument shown consists of an ion source, a vacuum system (not shown), an energy analyzer, and a detector. The major instrument components including the sample are under vacuum. 

Figure 3.28 Normative nepheline-oUvine-diopside-hypersthene-quartz projection after Thompson (1984), showing the compositions of initial melts in the CMAS system, MORE source and fertile anhydrous mantle at a range of pressures (in kb). The inset shows the relationship of the diagram to the surface of the Yoder-Tilley basalt tetrahedron.

The olivine- Grove et al. (1982, 1983) developed a projection scheme to present low-pressure clinopyroxene- experimental data for andesites in which the phases pkgioclase, olivine, augite, silica projection pigeonite and orthopyroxene are present. The diagram is useful for caJc-alkali series of Grove et al. rocks but may not be applicable for low-alkali-silica-rich suites. The projection (1982) scheme is similar to that of Walker et al. (1979) for tholeiitic basalts. It is based upon a modification of the CMAS projection in which wt% oxide values are converted to molecular proportions, alkalis and alumina are converted to NaO g 5j, K0 0 5] and AlO j, and the mineral components are calculated as molecular proportions as follows ... 

Figure 1.15 Process flow diagram for the oxidation of propylene with cumene hydroperoxide as the oxidizing agent and titanium-containing mesoporous material as the heterogeneous catalyst (Sumitomo process). The process involves the following steps (1) A process for oxidation of cumene with air to obtain CMHP, (2) a process for epox-idation of propylene in the presence of a catalyst whereby o,a-dimethyl benzyl-alcohol CMA) is concomitantly obtained from CMHP, (3) a process for the hydrogenation of CMA with H2 i n the presence of a catalyst to obtain cumene, (4) a process for purification of the cumene, followed by recycle of cumene to the oxidation process, and (5) a process for the purification of PO. Adapted from Ref. (271), with permission from Wiley-VCH.

Step la This CMA process is performed to verify that AND events (e.g. in the Fault Tree Analysis (FTA) or Dependence Diagrams (DD), or any quahtative probabihty declaration) are truly independent. 

Fig. 8. Compositional areas corresponding to glass-forming melts on ternary phase diagrams representing sections of tetrahedron of quatanary CMAS system at 47,54, and 63 wt. % of SiO .

Figure 6. Cross sectional schematic diagram for the calculation of the native oxide film thickness of d. The normal of the sample surface was set coincident with the axes of the CMA and the primary electron beam.

Two processes for production of 24 t/day of CMA from 10 lbs of cheese whey permeate per day utilizing the fibrous bed bioreactors were evaluated for product quality and manufacturing costs (Yang et al. 1999). O Figure 1.8 diagrams both processes. 

The study of QC surfaces has led to interest in the surfaces of related CMAs. QCs typically exist in a narrow composition region of the phase diagram due to the Hume-Rothery constraint of specific valence electron to atom ratio, which is related to electronic stabilization of QCs [196-198]. In the neighborhood of this composition region, phases with giant unit cells and local atomic order related to that of the QC can usually be found. The surfaces of these approximant phases offer the possibility of exploring surface structure and properties as a function of increasing complexity, which can be most simply defined in terms of atoms f>er unit cell. 

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