Classifier specificity

The distinction between specialist and generalist classifiers is quantified by the classifier specificity. The specificity of a classifier is determined by the number of symbols that it contains thus, it is a function of the form of the classifier. The specificity is larger the greater the number of Os and Is in the string, and is equal to the ratio of the total number of Os and Is, b to the total length of the string, 

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Food legislation in the US was implemented in 1938 and since then has been improved dynamically. The Food, Drug and Cosmetic Act classified specific colorants to be used in food and non-food products (FD C colorants). Each colorant has a color index (Cl) number and Cl name. Colorants are also identified by their Chemical Abstract Service (CAS) registry code numbers. The two groups are Certifiable Colorants and Exempt Colorants. 

There are target organ effects for which a substance/mixture may not meet the criteria to be classified in Categories 1 or 2 indicated above. These are effects which adversely alter human function for a short duration after exposure and from which humans may recover in a reasonable period without leaving significant alteration of structure or fimction. This category only includes narcotic effects and respiratory tract irritation. Substances/mixtures may be classified specifically for these effects as discussed in 3.8.2.2. 

The audit activities often find deficiencies in the completion of maintenance activities and missing links between equipment and the safety barriers (Ratnayake et al 2012). It is essential to know the links and interconnections between maintenance and technical safety disciplines. The safety analyses and identification of safety functions should be transferred to the maintenance engineers in order to classify specific equipment accordingly. Results of safety-related analyses performed by technical safety engineers should be prioritized over results of maintenance criticality analyses. Clear links should be established in order to ensure that one discipline s output can be used as input for other disciplines. The mandatory Performance Standards (PS) required by the PSA may be seen as a potential major link between safety and maintenance disciplines (Fig. 9). 

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification. 

The flash point of a petroleum liquid is the temperature to which it must be brought so that the vapor evolved burns spontaneously in the presence of a flame. For diesel fuel, the test is conducted according to a closed cup technique (NF T 60-103). The French specifications stipulate that the flash point should be between 55°C and 120°C. That constitutes a safety criterion during storage and distribution operations. Moreover, from an official viewpoint, petroleum products are classified in several groups according to their flash points which should never be exceeded. 

They are classified apart in this text because their use differs from that of petroleum solvents they are used as raw materials for petrochemicals, particularly as feeds to steam crackers. Naphthas are thus industrial intermediates and not consumer products. Consequently, naphthas are not subject to governmental specifications, but only to commercial specifications that are re-negotiated for each contract. Nevertheless, naphthas are in a relatively homogeneous class and represent a large enough tonnage so that the best known properties to be highlighted here. 

The products could be classified as a function of various criteria physical properties (in particular, volatility), the way they are created (primary distillation or conversion). Nevertheless, the classification most relevant to this discussion is linked to the end product use LPG, premium gasoline, kerosene and diesel oil, medium and heavy fuels, specialty products like solvents, lubricants, and asphalts. Indeed, the product specifications are generally related to the end use. Traditionally, they have to do with specific properties octane number for premium gasoline, cetane number for diesel oil as well as overall physical properties such as density, distillation curves and viscosity. 

A more detailed classification of chemical reactions will give specifications on the mechanism of a reaction electrophilic aromatic substitution, nucleophilic aliphatic substitution, etc. Details on this mechanism can be included to various degrees thus, nucleophilic aliphatic substitutions can further be classified into Sf l and reactions. However, as reaction conditions such as a change in solvent can shift a mechanism from one type to another, such details are of interest in the discussion of reaction mechanism but less so in reaction classification. 

In the last section we examined some of the categories into which polymers can be classified. Various aspects of molecular structure were used as the basis for classification in that section. Next we shall consider the chemical reactions that produce the molecules as a basis for classification. The objective of this discussion is simply to provide some orientation and to introduce some typical polymers. For this purpose a number of polymers may be classified as either addition or condensation polymers. Each of these classes of polymers are discussed in detail in Part II of this book, specifically Chaps. 5 and 6 for condensation and addition, respectively. Even though these categories are based on the reactions which produce the polymers, it should not be inferred that only two types of polymerization reactions exist. We have to start somewhere, and these two important categories are the usual place to begin. 

Forces of Adsorption. Adsorption may be classified as chemisorption or physical adsorption, depending on the nature of the surface forces. In physical adsorption the forces are relatively weak, involving mainly van der Waals (induced dipole—induced dipole) interactions, supplemented in many cases by electrostatic contributions from field gradient—dipole or —quadmpole interactions. By contrast, in chemisorption there is significant electron transfer, equivalent to the formation of a chemical bond between the sorbate and the soHd surface. Such interactions are both stronger and more specific than the forces of physical adsorption and are obviously limited to monolayer coverage. The differences in the general features of physical and chemisorption systems (Table 1) can be understood on the basis of this difference in the nature of the surface forces. 

Caustic soda is classified as a corrosive material by the DOT and DOT regulations and specifications must be followed for handling, labeling, and transportation in containers. Warning labels are recommended for containers of caustic soda solutions and anhydrous caustic soda by the MCA (79). The DOT identification number is UN1824 for 50 or 73% Hquid, and UN1823 for anhydrous caustic. 

The largest volume of hydrauHc fluids are mineral oils containing additives to meet specific requirements. These fluids comprise over 80% of the world demand (ca 3.6 x 10 L (944 x 10 gal))- In contrast world demand for fire-resistant fluids is only about 5% of the total industrial fluid market. Fire-resistant fluids are classified as high water-base fluids, water-in-oil emulsions, glycols, and phosphate esters. Polyolesters having shear-stable mist suppressant also meet some fire-resistant tests. 

Shipment of hydrazine solutions is regulated in the United States by the Department of Transportation (DOT) which classifies all aqueous solutions between 64.4 and 37% N2H4 as "Corrosive" materials with a subsidiary risk of "Poison". Hydrazine has been identified by both the Environmental Protection Agency and the DOT as a hazardous material and has been assigned a reportable quantity (RQ) of 0.450 kg (1 lb) if spilled. Dmms for the shipment of these solutions must bear both the DOT specification "Corrosive" and "Poison" labels in association with the markings "RQ Hydrazine Aqueous Solution UN 2030." Aqueous solutions of 37% concentration or less are a hazard Class 6.1, UN 3293, Packing Group III and require "Keep Away From Food" placards and labels. 

The Department of Transportation classifies HCl as a corrosive material and requires that it be transported in DOT-approved deHvery vessels. Tank cars must conform to 103B, 103B-W, or DOT 111A60W5 specifications. Tank trailers must conform to DOT MC-310, MC-311, MC-312, or DOT-412 specifications with display of a corrosive placard on both sides, front, and rear of the tank. The United Nations identification number for muriatic acid is UN1789, which must appear on aH shipping papers and placards. 

W-type inks use water, or mixtures of water and alcohol, as the solvent. Inks which are not of a recognized type are classified as X-type. The solvent required is specific to the ink formula and the ink maker makes proper recommendations. 

Health and Safety Factors. Dimethyl malonate and diethyl malonate do not present any specific danger of health ha2ard if handled with the usual precautions. Nevertheless, inhalation and skin contact should be avoided. Dimethyl malonate has a LD q (oral, rats) of 4520 mg/kg and is classified as nonirritant (skin irritation, rabbits). Diethyl malonate has an LD q (oral, rats) greater than 5000 mg/kg and is also classified as nonirritant (skin irritation, rabbits). Transport classification for both esters is RID/ADR 3, IMDH-Code, lATA-ICAO not restricted. 

Health and Safety Factors. Handling of cyanoacetic acid and cyanoacetates do not present any specific danger or health hazard if handled with the usual precautions. Cyanoacetic acid is classified as a moderate irritant (skin irritation, rabbits) and has an LD q (oral, rats) of 1500 mg/kg. Methyl and ethyl cyanoacetate are both classified as slight irritants (skin irritation, rabbits) and have an LD q (oral, rats) of 3062 and 2820 mg/kg, respectively. Transport classification cyanoacetic acid RID/ADR 8 IMDG-Code 8 lATA/ICAO 6.1. Methyl and ethyl cyanoacetate RID/ADR 6.1 IMDG-Code 6.1 lATA/ICAO 6.1. 

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