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. 

Figure 8.3. Fatty acid composition of anhydrous milk fat and selected milk fat fractions grouped in short chain, medium chain and long chain saturated fatty acids and unsaturated fatty acids. For definition of fractions, see Figure 8.1. The numbers in the bars give the percentage of the group of fatty acids. Data from Deffense (1987, Table 3).

Fig. 9. Comparison of amino acid sequences of bovine mouse rat a, a (partial), retinal rod and cone cells < bacterial elongation factor EFTu and c-Ha-ras, aligned to maximize matching. This leads to the definition of an aavp of 3% amino acids (numbers above sequences). Boxes surround identical or conserved residues, (c) and (p), residues ADP-ribosylated by CTX and PTX, respectively. —A—, — C—, —E— and —G—, sequences known to be intimately involved in guanine nucleotide binding by EFTu (From Refs. 175 and 176).

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... 

Langmuir-Hinshelwood kinetics adsorption inhibition, 62 consistency of, 66 rate-controlling step for, 60 two-step model for, 67 Langmuir-Hinshelwood mechanism, 60 Lewis acid, 6 Lewis number definition of, 107 stability as affected by, 266 Local activity factor, 465 Lumping, 81... 

Short chains of amino acid residues are known as di-, tri-, tetrapeptide, and so on, but as the number of residues increases the general names oligopeptide and polypeptide are used. When the number of chains grow to hundreds, the name protein is used. There is no definite point at which the name polypeptide is dropped for protein. Twenty common amino acids appear regularly in peptides and proteins of all species. Each has a distinctive side chain (R in Figure 45.3) varying in size, charge, and chemical reactivity. 

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. 

Bismuth Oxides and Bismuthates. The only oxide of bismuth that has been definitely isolated in a pure state is bismuth trioxide. An acidic oxide that approximates the composition Bi20 certainly exists. However, there is considerable question as to the exact nature of this material and the species involved. A number of other oxides have been reported, eg, bismuth oxide (1 1) [1332-64-5], bismuth oxide (1 2), bismuth oxide (2 4)... 

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). 

In contrast, RNA occurs in multiple copies and various forms (Table 11.2). Cells contain up to eight times as much RNA as DNA. RNA has a number of important biological functions, and on this basis, RNA molecules are categorized into several major types messenger RNA, ribosomal RNA, and transfer RNA. Eukaryotic cells contain an additional type, small nuclear RNA (snRNA). With these basic definitions in mind, let s now briefly consider the chemical and structural nature of DNA and the various RNAs. Chapter 12 elaborates on methods to determine the primary structure of nucleic acids by sequencing methods and discusses the secondary and tertiary structures of DNA and RNA. Part rV, Information Transfer, includes a detailed treatment of the dynamic role of nucleic acids in the molecular biology of the cell. 

The concept of oxidation number leads directly to a working definition of the terms oxidation and reduction. Oxidation is defined as an increase in oxidation number and reduction as a decrease in oxidation number. Consider once again the reaction of zinc with a strong acid ... 

Discussion. The turbidity of a dilute barium sulphate suspension is difficult to reproduce it is therefore essential to adhere rigidly to the experimental procedure detailed below. The velocity of the precipitation, as well as the concentration of the reactants, must be controlled by adding (after all the other components are present) pure solid barium chloride of definite grain size. The rate of solution of the barium chloride controls the velocity of the reaction. Sodium chloride and hydrochloric acid are added before the precipitation in order to inhibit the growth of microcrystals of barium sulphate the optimum pH is maintained and minimises the effect of variable amounts of other electrolytes present in the sample upon the size of the suspended barium sulphate particles. A glycerol-ethanol solution helps to stabilise the turbidity. The reaction vessel is shaken gently in order to obtain a uniform particle size each vessel should be shaken at the same rate and the same number of times. The unknown must be treated exactly like the standard solution. The interval between the time of precipitation and measurement must be kept constant. 

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