Classification Convention

Sign Conventions Since the reaction of interest occurs at the working electrode, the classification of current is based on this reaction. A current due to the analyte s reduction is called a cathodic current and, by convention, is considered positive. Anodic currents are due to oxidation reactions and carry a negative value. 

No method has been devised to estimate with complete accuracy the amount of cmde petroleum that ultimately will be produced from the world s conventional oil and gas fields. Degrees of uncertainty, therefore, should be attached to all such estimates. These uncertainties can be expressed in several ways, the most important of which is achieved by dividing a resource into various categories. Several petroleum resources classifications have been proposed, and a comprehensive discussion of them (1), as well as the definition used in the assessment of the undiscovered resources of the United States (2), have been provided. Seven commonly used categories of resources are given here. 

There are three generally recognized classifications for sulfur vulcanization conventional, efficient (EV) cures, and semiefficient (semi-EV) cures. These differ primarily ki the type of sulfur cross-links that form, which ki turn significantly influences the vulcanizate properties (Eig. 8) (21). The term efficient refers to the number of sulfur atoms per cross-link an efficiency factor (E) has been proposed (20). 

High-Rate Thickeners Flocculants are commonly used in thickeners, and this practice has resulted in thickener classification as either conventional or high-rate. These designations can be confusing in that they imply that there is a sharp distinction between the two. 

Conventional Wastes Sources and types of industrial solid wastes generated by Standard Industrial Classification (SIC) group classification are reported in Table 25-49. The expected specific wastes in the table are those that are most readily identifiable. 

Control efficiency ranges for single cyclones are often based on three classifications of cyclone, i.e., conventional, high-efficiency, and high-throughput. The control efficiency range for conventional single cyclones is estimated to be 70 to 90 percent for PM, 30 to 90 percent for PMio, and 0 to 40 percent for PMj 5. 

By convention, classification has been defined as the particle size of which 1 % to 3 % reports to the cyclone overflow with coarser particles reporting to the cyclone underflow. Recent investigations reported by Arterbum (1999) have defined classification as the particle size of which 50% reports to the overflow and 50% to... 

Besides the conventional classification of flow shown in Fig. 14.3, there arc also other possibilities, sec, e.g., Leung, Independent of the method of classification, the essential point is that there is no general method and there are no general simple parameters that reliably predict the behavior of the flow in a new application. For each case the type ot flow has to be examined experimentally. 

The basic nature of composite materials was introduced in Chapter 1. An overall classification scheme was presented, and the mechanical behavior aspects of composite materials that differ from those of conventional materials were described in a qualitative fashion. The book was then restricted to laminated fiber-reinforced composite mafeffals. The basic definitions and how such materials are made were then treated. Finally, the current and potential advantages of composite materials were discussed along with some case histories that clearly reveal how composite materials are used in structures. 

The four-character bit code is entered on an lADC-API Daily Drilling Report Form as shown in Figure 4-157. The space requirements are consistent with the four-character lADC roller bit classification code. The two codes are readily distinguished from one another by the convention that diamond bit codes begin with a letter, while roller bit codes begin with a number. 

This classification was devised by the Society of Automotive Engineers (SAE) in America by dividing the viscosity span into four and giving each of the divisions a number - SAE 20, 30, 40 and 50. The thinnest (SAE 20), for example, covered the range 5.7-9.6cSt specified at 210°F, which was considered to be a temperature typical of a hot engine. (The SAE originally specified temperatures in °F, because they were the convention. Today, temperatures are quoted in °C.)... 

The lubricants generally specified for conventional gas turbines invariably fall within the same classification as those used for steam turbines and are often categorized as turbine oils . In those cases where an aircraft type gas turbine has been adapted for industrial use the lubricant is vitally important to their correct operation. Specifications have been rigidly laid down after the most exhaustive tests, and it would be unwise, even foolhardy, to depart from the manufacturers recommendations. No economic gain would result from the use of cheaper, but less efficient, lubricants. 

Of course it is important to distinguish between the shape of the periodic table, which is admittedly a matter of choice or convention, from tables that actually place certain elements in different groups. The point is not whether one should favor a tabular form, in which periods end abruptly, over circular displays which emphasize the continuity of the sequence of the elements for example. The question is rather whether to favor a table that places the element helium among the noble gases, when compared with tables that place this element among the alkaline earths. The wider question is whether elemental classification is an objective matter of fact or whether it is a matter of convention. It is the question of whether helium, for example, has a natural kinship with the noble gases or with the alkaline earths. Or as philosophers of science are apt to say, it is the question of whether or not groups, or families of elements, represent natural kinds. 

In this article it will be argued that the classification of the elements is an objective feature of the world and not open to conventional choice and relativism. It will also be argued that the element helium belongs objectively and most naturally either to the alkaline earths or the noble gases regardless of whether such a question may be settled at present.8... 

What will now be proposed is that in addition to its role in ordering the elements, the quantity Z may be used to also affect a secondary classification of the elements, that is, their placement into vertical groups in the sense of the conventional periodic table. In proposing this idea, I make use of what was historically the earliest hint of chemical periodicity, namely, the existence of triads of elements [35]. 

In any heterolytic reaction in which a new carbon-carbon bond is formed one carbon atoms attacks as a nucleophile and the other as an electrophile. The classification of a given reaction as nucleophilic or electrophilic is a matter of convention and is usually based on analogy. Although not discussed in this chapter, 11-12-11-28 and 12-14-12-19 are nucleophilic substitutions with respect to one reactant, though, following convention, we classify them with respect to the other. Similarly, all the reactions in this section (10-93-10-123) would be called electrophilic substitution (aromatic or aliphatic) if we were to consider the reagent as the substrate. 

All conventional classification procedures are aimed at answering one of the following questions ... 

A machine-learning method was proposed by Klon et al. [104] as an alternative form of consensus scoring. The method proved unsuccessful for PKB, but showed promise for the phosphatase PTPIB (protein tyrosine phosphatase IB). In this approach, compounds were first docked into the receptor and scored using conventional means. The top scoring compounds were then assumed to be active and used to build a naive Bayes classification model, all compounds were subsequently re-scored and ranked using the model. The method is heavily dependent upon predicting accurate binding... 

The difficulties in conventional polarography as mentioned in Section 3.3.1.1, especially the interference due to the charging current, have led to a series of most interesting developments by means of which these problems can be solved in various ways and to different extents. The newer methods concerned can be divided into controlled-potential techniques and controlled-current techniques. A more striking and practical division is the distinction between advanced DC polarography and AC polarography. These divisions and their further classification are illustrated in Table 3.1. In treating the different classes we have not applied a net separation between their principles, theory and practice, because these aspects are far too interrelated within each class. 

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