Total acid number , definition

Wear experiments have been carried out on a three-roller-on-ring machine. Some characteristic correlations (ATAN) of the deteriorated engine oils used in the wear experiment are summarized in Table 6.9. An effect of deterioration of petrol engine oil on wear was that an increase in the total acid number of the deteriorated oil above an initial value had a definite correlation with wear of steel. 

Absolute porosity, definition, 220 Absolute viscosity, definition, 386 Acid number (total acid number, TAN), definition, 403 Adhesion, definition, 26-27 Adsorbed polymer layers, interaction with droplets, 62 Adsorption definition, 386... 

When the acid number for a cmde oil is known, we want to estimate how much soap can be generated, assuming (1) the required alkali is available, which is generally trae and (2) the total surface-active agents are converted into soap, which is generally not tme, as discussed in Section 12.9.2. Based on the definition that acid number (AN) is the amount of potassium hydroxide in milligrams that is needed to neutralize the acids in one gram of oil, the soap concentration, Csoap, in meq/mL is... 

Capacity. Capacity is a measure of the quantity of ions, acid, or base removed (adsorbed) by an ion-exchange material. The quantity removed is direcdy correlated with the number of functional groups. Capacity is reported ia several different ways, but requites further definition because the word by itself does not cover ad situations. Total capacity is a measure of ad the functional groups on a resia and is recorded on a weight as wed as a volume basis. 

Retrosynthetic analysis of antheridic acid produced a totally different plan of synthesis from that which had been employed for the structurally related target gibberellic acid. The synthesis of antheridic acid, which included a number of novel steps, allowed definitive assignment of structure and revised stereochemistry at C(3). 

There are two definitions of protein hydrophobicity average hydrophobicity and surface hydrophobicity. The average hydrophobicity was defined by Bigelow (1967) as the total hydrophobicity of all amino acid residues comprising a protein divided by the number of amino acids in the protein. There is no standard definition of surface (or effective) hydrophobicity except the concept that there must be hydrophobic regions on the molecular surface that play an effective role in protein function. Readers who are interested in a more detailed discussion are referred to Nakai and Li-Chan (1988). 

Typical values of pK[nt and pfor a humic acid are 2.67 and 4.46. The introduction of the electrostatic factor into the equilibrium constant is analogous to the coulombic term used in the definition of the intrinsic surface complexation constants. In addition another binding site (WAH) is recognised which is thought to behave as a weak acidic phenolic functional group. Although this site does not contribute to the titratable acidity and, therefore, no pK is needed for proton dissociation, it is involved in metal complexation reactions. The total number of the three monoprotic sites is estimated from titratable acidity and then paired to represent the humic substance as a discrete non-interacting mixture of three dipro-tic acids, which act as the metal complexation sites. The three sites are... 

For the sake of completeness, several components have been included in Table XII-2 because they possess the amine function (-NH2) but are not linked to a carbon atom, for example, ammonia, hydrazine, and hydroxylam-ine. None of them fits the definition of an amide, imide, or lactam. Other components included in Table XII-2 for the sake of completeness are the amino acids with acyclic unsubstituted or substituted amine groups, the acyclic A-nitrosamines, and the A-heterocyclic amines. With the inclusion in Table XII-2 of the various items just mentioned, the number of acyclic amines and their derivatives total 469, with 259 identified in smoke, 316 in tobacco, and 106 in both tobacco and smoke. 

To avoid confusion, it is necessary to reemphasize the definition of structural unit — the residue fi om a glycol or from a dibasic acid. This means that the number of structural units equals the total number of bifonctional monomers initially present. Thus the repeating unit of a chain derived from A-A/B-B type monomers consists of two structural units, while the repeat unit in the case of type A-B monomers is the same as the structural unit. 

The chemical composition of the framework has a definite impact on the acid strength of zeolites and zeotypes. The total number of Bronsted acid sites present in a zeolite depends on the framework Si/Al ratio or in general on the cations. The variation of stretching frequency of bridging hydroxyls [94] and results from H NMR spectra [95] suggest that the strength of Bronsted sites in HY zeolites increases with decreasing Si/Al ratio. This has been rationalized with the concept of... 

Bergmann held it to be of utmost significance that the experimentally determined values [for the total number of amino acids and the frequency of each amino acid] led to values [of the total number of amino acids in a protein] which were unique whole multiples of 288 or 2 X Therefore, Bergmann believed, each protein is composed of one or more units of 288 amino acids arranged in a definite order. For example ... 

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