Categorical quantities

FIGURE 7.33 Some relative nucleophilicities. Be careful Nucleophilicity (Lewis basicity) is a hard-to-categorize quantity. Relative nucleophilicity depends, for example, on the identity of the reaction partner, which is always a Lewis acid, as well as the nature of the solvent. 

Explosives are commonly categorized as primary, secondary, or high explosives. Primary or initiator explosives are the most sensitive to heat, friction, impact, shock, and electrostatic energy. These have been studied in considerable detail because of the almost unique capabiUty, even when present in small quantities, to rapidly transform a low energy stimulus into a high intensity shock wave. 

These models are usually categorized according to the number of supplementary partial differential transport equations which must be solved to supply the modeling parameters. The so-called zero-equation models do not use any differential equation to describe the turbulent quantities. The best known example is the Prandtl (19) mixing length hypothesis ... 

Kass, G.V (1980). An exploratory technique for investigating large quantities of categorical data. Appl. Stat. 29 119-127. 

Electronegativity is a very useful quantity to help categorize bonds, because it provides a measure of the excess binding energy between atoms A and B, Aa-b (in kJ/mol) ... 

The characteristics of a chemical or substance that would categorize it as a reactive material include (1) it reacts violently with water, (2) it forms potentially explosive mixtures with water, or (3) when mixed widi water or other chemicals, it generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment. Because water is the most common fire suppressant, the characteristic of reactivity is especially relevant since the application of water to eliminate or prevent the spread fires may be counterpro-ductive rather than helpful. Several categories of chemicals will be discussed from this standpoint however, several of these same chemicals also present additional hazards. 

In Section 1.1, parametric methods for improving tlie quality of correlated electronic-structure calculations were discussed in detail. Similarly, in Section 8.4.3, the mild parameterization of density functional methods to give maximal accuracy was described. Given that background, and the substantial data presented in diose earlier chapters, this section will only recapitulate in a rough categorical fashion tlie various approaches whose development was motivated by a desire to compute more accurate thermochemical quantities. 

A material that is added to a formulation that increases the quantity of formulation required for a process without actually changing the formulation s reactivity. Example Barium sulfate is sometimes added during processing to increase the density of polyurethane (solid) foam. (CAPICO) A system in which potential cosmetic emulsion ingredients are numerically categorized so that one may calculate their influence on the phase inversion temperature of a formulated emulsion. 

A viscous flow takes place when the effects of viscosity become significant. This type of flow can be categorized as either a laminar flow or a turbulent flow [72], A laminar flow is one with no considerable mixing of neighboring fluid particles, apart from molecular motion. In a turbulent flow, the quantities which typify the flow exhibit a random variation with the time and space coordinates. The quantity used to predict the type of flow regime is the Reynolds number (Re), which is a dimensionless parameter defined as [72]... 

Although limited in quantity, natural extracts still enjoy an irreplaceable status in smoothing and integrating the aroma of products.33,95,96 Raw materials used for F F can be categorized depending on the part of the plant used. In the following subsections, several representative raw materials from flower, leaves, root, grass, seed, wood, resin, the miscellaneous botanical mass as well as those from animal sources are described. 

Mineral additions may be broadly categorized as pozzolanic materials or latent hydraulic cements. Neither type reacts significantly with water at ordinary temperatures in the absence of other substances. Pozzolanic materials are high in Si02 and often also in AI2O3, and low in CaO they are sufficiently reactive that mixtures of them with water and CaO produce C-S-H at ordinary temperatures and thereby act as hydraulic cements. If they contain AI2O3, calcium aluminate or aluminate silicate hydrates are also formed. Because they are low in CaO, this component must be supplied in stoichiometric quantity. In a composite cement, it is provided by the Portland cement through decreased formation of CH and decreased Ca/Si... 

A large number of electrochemical methods exist which are or have the potential to be useful in the study of reactive intermediates. The methods are conveniently categorized according to the quantity measured, usually the current, potential, or some optical property of the reactants or the intermediates. A further classification arises from the manner in which experiments are conducted, i.e. transient or steady state measurements. In this brief survey only those techniques which have been reduced to useful practice are discussed and even then the coverage is not exhaustive. More detailed discussion can be found in several excellent references sources (Bard, 1966-present MacDonald, 1977 Bard and Faulkner, 1980). 

Vitamins are organic compounds required in small quantities for norma] metabolism (Section 3.5). Because our cells cannot synthesize these compounds, they must be obtained in the diet. Vitamins can be categorized as fat soluble or water soluble. The fat-soIuble vitamins are lipids. 

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