Class mark

The mass of material in a particular molecular weight class is given by the product of the class mark molecular weight and the number of molecules in the class ... 

The temperature class marked on equipment shall be as shown in Table 505-10(b). 

Similarly the alchemical Elements and Principles were useful class-marks. 

Since the time of Lavoisier, since the last decade of the eighteenth century, careful chemists have meant by an element a substance which has not been separated into unlike parts, and they have not meant more than that. The term element has been used by accurate thinkers as a useful class-mark which connotes a property—the property of not having been decomposed—common to all substances placed in the class, and differentiating them from all other substances. Whenever chemists have thought of elements as the ultimate kinds of matter with which the physical world is constructed—and they have occasionally so thought and written— they have fallen into quagmires of confusion. 

Class boundaries total number in class Total number with d < d nT.,... 

As described in Appendix C, if we have a discrete set of measurements of a quantity such as the diameters of particles, one can represent the results in terms of a few useful quantities like the average diameter and standard deviation. Table 1.5 represents the frequency distribution for a hypothetical array of spheres all the numerical examples of this section are based on this sample of 400 particles. The particles have been sorted into categories called classes with a narrower range of dimensions. Each class is represented by the midpoint of the interval, a quantity called the class mark, symbolized by d, for class i. Similarly, we define the number of particles in each class as nr... 

Another way in which these kinds of data are sometimes represented is as a cumulative curve in which the total number (or fraction) of particles nT>, having diameters less (sometimes more) than and including a particular d, are plotted versus dr Figure 1.18b shows the cumulative plot for the same data shown in Figure 1.18a as a histogram. The cumulative curve is equivalent to the integral of the frequency distribution up to the specified class mark. Cumulative distribution curves are used in Chapter 2 in connection with sedimentation. 

Morphine p agonist— strong (full) +++ +++ +++ Prototype of the class, marked sedation, poor oral bioavailability, histamine release... 

Fluorinated Acids. This class of compounds is characterized by the strength of the fluorocarbon acids, eg, CF COOH, approaching that of mineral acids. This property results from the strong inductive effect of fluorine and is markedly less when the fluorocarbon group is moved away from the carbonyl group. Generally, their reactions are similar to organic acids and they find apphcations, particularly trifluoroacetic acid [76-05-1] and its anhydride [407-25-0] as promotors in the preparation of esters and ketones and in nitration reactions. 

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. 

Shipping vitamin D in crystalline or resin form should be done in containers marked appropriately to indicate the material is toxic by DOT standards. Its proper DOT labeling is DOT Hazard Class 6.1, poisonous. Waste material should be burned or placed in an appropriate landfill. 

Calcium carbide is classed as a ha2ardous chemical under Department of Transportation regulations. Domestic shipments are mainly in steel tote bins varying in capacity from 2.5—4.5 t. A small amount continues to be shipped in industrial wide mouth steel dmms of 270 kg capacity. Containers must be marked "Flammable soHd, dangerous when wet" and have the United Nations designation UN 1402. 

Glass IG Antiarrhythmic Agents. Class IC antiarrhythmic agents have marked local anesthetic effects. They slow the rapid inward sodium current producing marked phase 0 depression and slow conduction. Action potential duration of ventricular muscle is increased, ie, prolonged repolarization, but decreased in the His-Purkinie system by these agents. The effects on the ECG are increased PR interval, marked prolongation of the... 

The Class III antiarrhythmic agents markedly prolong action potential duration and effective refractory period of cardiac tissue. The QT interval of the ECG is markedly prolonged. 

It is possible to go beyond the SASA/PB approximation and develop better approximations to current implicit solvent representations with sophisticated statistical mechanical models based on distribution functions or integral equations (see Section V.A). An alternative intermediate approach consists in including a small number of explicit solvent molecules near the solute while the influence of the remain bulk solvent molecules is taken into account implicitly (see Section V.B). On the other hand, in some cases it is necessary to use a treatment that is markedly simpler than SASA/PB to carry out extensive conformational searches. In such situations, it possible to use empirical models that describe the entire solvation free energy on the basis of the SASA (see Section V.C). An even simpler class of approximations consists in using infonnation-based potentials constructed to mimic and reproduce the statistical trends observed in macromolecular structures (see Section V.D). Although the microscopic basis of these approximations is not yet formally linked to a statistical mechanical formulation of implicit solvent, full SASA models and empirical information-based potentials may be very effective for particular problems. 

Enclosure considerations (interlocks, insulation class, shock, marking, etc.). 

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