Classification methods definition

The Fire Services Law was revised in May, 1988, and the listing of hazardous materials has been also revised as shown in Table 1.1. The new definition of hazardous materials under the revised Fire Services Law employs modem classification methods utilizing special evaluation techniques. The following quotation comes from the official gazette and demonstrates the principle of the revision 2 5 . ... 

The dimensionality of chemical structure space exceeds that of known biological functional space. The dimensionality of biological functional space has increased in recent years due to the discovery of a multitude of genes, largely from the Human Genome Project. This chapter, however, will focus on chemical diversity rather than functional diversity. Quantification of chemical diversity involves two areas first, the predefmition of a chemical space, accomplished by selection of a diversity metric and a compound representation (i.e., molecular descriptors) and second, a rational subset selection, or classification, method dependent on efficient dimensionality reduction. Here, we describe these methods, prerequisites for a definition... 

FIGURE 2.1 General classification and definitions of computational methods employed in molecular design in chemistry and biology. 

W.E. van der Linden, Classification and definition of methods based on flowing media, Pure Appl. Chem. 66 (1994) 2493. 

Because of the descriptive nature of the flammable solid and oxidizer definitions it is difficult to determine if a material falls within the definition of either hazard class. In efforts to make both definitions more specific and to provide tests which would allow appropriate classification, the Materials Transportation Bureau has requested comments on new definitions and proposed test methods for the flammable solid and oxidizer hazard classes. The reader should become aware of these test methods definitions since they could become part of the regulatory framework. In addition, the test methods could serve as guidance, even at present, for decisions involved in classifying a material as a flammable solid or as an oxidizer. 

It follows that individual measuring methods depend upon particle definition. Particle definitions might include such details as number, length, surface area, mass, and volume, as a result of which one has the choice of using various counting methods - microscopy, image analyzers, laser diffraction, as well as sieving and air classification methods. 

Besides the common types of conveyor, CEMA standards also address classifications and definitions of bulk materials. CEMA 550, for example, presents an alphanumeric method for classif5dng bulk density, particle size, flowability, abrasiveness, and handling characteristics of solids. The identifier contains, in order ... 

American Society for Testing and Materials n ASTM. A nonprofit corporation formed for the development of standards on characteristics and performance of materials, products, systems, and services, and the promotion of related knowledge. In ASTM terminology, standards include test methods, definitions, recommended practices, classifications, and specifications. 

The American Society for Testing and Materials (ASTM) 1916 Race Street Philadelphia, Pa. 19103 The ASTM MnnualBook ofMSTM Standards contains all up-to-date formally approved (ca 9000) ASTM standard specifications, test methods, classifications, definitions, practices, and related materials, eg, proposals. These are arranged in 15 sections plus an index volume as follows. 

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. 

Clays (qv) are aluminosihcate minerals, some of which have definite chemical compositions. In regard to tar sands, however, clay is only a size classification and is usually deterrnined by a sedimentation method. According to the previous definition of fines, the fines fraction equals the sum of the silt and clay fractions. The clay fraction over a wide range of fines contents is a relatively constant 30% of the fines. 

Definitions and Classification Figure 22-41 outhnes the most widely accepted classification of the various adsubble methods [Karger, Grieves, Lemhch, Rubin, and Sebba, Sep. Sci, 2,401 (1967)]. It is based largely on ac tual usage of the terms by various workers, and so the definitions include some unavoidable inconsistencies and overlap. 

The chemical and physical properties of the polymers obtained by these alternate methods are identical, except insofar as they are affected by differences in molecular weight. In order to avoid the confusion which would result if classification of the products were to be based on the method of synthesis actually employed in each case, it has been proposed that the substance be referred to as a condensation polymer in such instances, irrespective of whether a condensation or an addition polymerization process was used in its preparation. The cyclic compound is after all a condensation product of one or more bifunctional compounds, and in this sense the linear polymer obtained from the cyclic intermediate can be regarded as the polymeric derivative of the bifunctional monomer(s). Furthermore, each of the polymers listed in Table III may be degraded to bifunctional monomers differing in composition from the structural unit, although such degradation of polyethylene oxide and the polythioether may be difficult. Apart from the demands of any particular definition, it is clearly desirable to include all of these substances among the condensation... 

In the method of classification of matter based on composition, a given specimen of material is regarded as either a pure substance or a mixture. An outline of this classification scheme is shown in Table 1-2. The term pure substance (or merely substance) refers to a material all parts of which have the same composition and which has a definite and unique set of properties. In contrast, a mixture consists of two or more substances and has a somewhat arbitrary composition. The properties of a mixture are not unique, but depend on its composition. The properties of a mixture tend to reflect the properties of the substances of which it is composed that is, if the composition is changed a little, the properties will change a little. 

Considering now a few common methods and techniques for the experimental definition of a phase diagram, it may be useful to refer to their usual classification into two groups polythermal and isothermal methods. 

Since this type of result shows that sonication is definitely not just another method of providing agitation of a medium, but exhibits its own peculiarities, it stands to reason that it should obey some rules of its own. An examination and classification of published material led to an empirical systemisation of sonochemistry [28, 30). This classification concentrates on the chemical effects in sonochemistry but it should also be recognised that in some cases ultrasound does act in a mechanical sense achieving remarkable results through super agitation. Sometimes the mechanical and chemical effects occur together. 

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