Alumina secondary component

The fact that LEIS provides quantitative information on the outer layer composition of multi-component materials makes this technique an extremely powerful tool for the characterization of catalysts. Figure 4.19 shows the LEIS spectrum of an alumina-supported copper catalyst, taken with an incident beam of 3 keV 4He+ ions. Peaks due to Cu, A1 and O and a fluorine impurity are readily recognized. The high intensity between about 40 and 250 eV is due to secondary (sputtered) ions. The fact that this peak starts at about 40 eV indicates that the sample has charged positively. Of course, the energy scale needs to be corrected for this charge shift before kinematic factors Ef/E-, are determined. 

Accordingly, work has been done on series of n-paraffins,. isoparaffins, naphthenes, aromatics, and naphthene-aromatics which have been chosen as representative of the major components of petroleum. In addition, olefins, cyclo-olefins, and aromatic olefins have been studied as a means of depicting the important secondary reactions of the copious amounts of unsaturates produced in the majority of catalytic cracking reactions. A silica-zirconia-alumina catalyst was used principally it resembles closely in cracking properties typical commercial synthetic silica-alumina catalysts. 

Ceramic materials are also utilized in nuclear reactor components. Applications include insulation of pressure vessels with linings fabricated from silica and alumina-base ceramic bricks or fiber insulation pressure vessels made of prestressed concrete structures that enclose the entire reactor and secondary system wear-resistant surfaces produced by means of coatings such as chromium oxide or chromium carbide and shielding applications, which include materials such as concrete, graphite, and leaded glass ... 

This double spot formation is not observed on silica gel or alumina layers. The sensitivity to oxidation of the adrenaline derivatives is, however, increased by the metal or heavy metal impurities present in such layers. Adrenaline and noradrenaline have therefore been chromatographed on buffered silica gel layers (Sorensen buffer, pH 6.8), prepared with addition of sodium bisulphite and using 10% ethanol as solvent [163]. The sympathomimetics and the secondary products formed by oxidation tend moreover to form complex salts this manifests itself in elongated spots. Silica gel layers which had been prepared with O.IM EDTA have been used with the solvent acetone-formic acid-water (70 + 10 + 20) for the separation of adrenaline, noradrenaline and various substances of similar structure [110] silica gel HR (Krm 88) ought to be especially advisable for this purpose. On the other hand, Halmekoski [74] has made use of this very ability of the adrenaline-type of sympathomimetic to form complexes, in order to accomplish fractionation on buffered layers containing molybdate, tungstate or borax components... 

During the adsorption process, a device (reactor, dryer, etc.) is filled with a porous solid designed to remove gases or liquids from a mixture. Typically the process is run in parallel with a primary and secondary vessel. The adsorber can be activated alumina or charcoal. A variety of adsorption materials can be used. The adsorption material has selective properties that will remove specific components of the mixture as it passes over the adsorber. A stripping gas is used to remove the stripped components from the adsorption material. 

The ZEBRA battery comprises a NiCU positive electrode in a central compartment with NaCl salt, impregnated with NaAlCls, which is a liquid mixture of NaCl and AICI3 (considered to be a secondary electrolyte). The negative electrode is liquid sodium confined in a second, outer compartment. The wall separating the two compartments is made of a P alumina ceramic (or P-AI2O3), conductive of sodium ions, considered to be the primary electrolyte. The element is sealed hermetically and functions at temperatures equal to or higher than 300°C so that the active components remain in the liquid state. 

---