Role Indicator

In the study of adsorptive desulfurization of a model diesel fuel over a nickel-based sorbent in a fixed-bed adsorption system at ambient temperature and atmosphere pressure, Kim et al.123 found that the direct interaction between the sulfur atom in the sulfur compounds and the surface nickel plays an important role, indicating that the supported nickel adsorbent is good for the selective removal of the sulfur compounds, which have no alkyl steric hindrance, from hydrocarbon streams. However, the sorption affinity of the alkyl DBTs with alkyl groups at 4- and/or 6-positions is reduced due to the steric hindrance. The sorption selectivity of the nickel-based sorbent for various compounds at room temperature increases in the order of Nap 1-MNap < 4,6-DMDBT < DBT < quinoline < indole, as shown in Figure 5.14.123... 

Pitch and role indicators Engine thrust indication Radio Altitude... 

Figure 9 shows that increase in the excited state quencher concentration gives rise to an increased width of the reflection band. The fact that intensity plays a very important role indicates the competition between the phase separation process which causes the increase as opposed to the polymerisation speed which tends to freeze in the structure and the pitch present within the system. Such a pitch gradient has been observed in polymerized acrylate networks (9). In the case of studies of other gels, the band broadening occurred as the system phase separated into two regions containing liquid crystal and the liquid crystal swollen network. 

Common practice in indexing documents that discuss chemical reactions is to index each reaction in its own link. When role indicators are added, this technique simulates a reaction database. Roles are used for every chemical, but experience has shown that an elaborate set of roles leads to redundant indexing . This database uses reactant, product, special agent, medium, and other (used when the aforementioned do not apply). A typical record is illustrated by Figure 8. 

In the CA File, Registry Numbers may occur in combination with different letters. These letters are called Role Indicators, disclosing the context of the compound in the document ... 

The letter P after a Registry Number describes the preparation of the compound. The searching of a Registry Number without a Role Indicator will automatically search for citations with the suffix P. Restriction to documents concerning preparations of substances may be added fi om the start ... 

The non-specific derivatives e.g. include polychlorinated biphenyls or dioxi-nes. They cannot be found without the role indicator D being added to the Registry Number. This search statement will also retrieve all the documents with a role indicator DP added to their Registry Number. 

Role Indicators are automatically assigned to the CA documents by computer-algorithms, analyzing every entry. However, a search for the preparation of a substance should not be confined to the Role Indicators (Sect. 7.3.2.3). The suffixes D and DP have only been used since 1977, tenth collective index period (CAVol. 86). 

Moreover, ORBIT has prepared some unique features. The Role Indicators that are added to the Registry Numbers by CAS, are supplemented by an ORBIT computer program (Fig. 172). Every Registry Number may receive several additional Role Indicators which can be searched for independently. The search for 99-93-4A will equally retrieve 99-93-4AP. The following supplements can be added to the Registry Numbers ... 

Role indicator letter behind the CAS Registry Number in the Chemical Abstracts database describing the contents, e.g. P for preparation. 

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