Class B

Each country adopts such and such a class as a function of its climatic conditions. France has chosen classes B, E, and F, respectively for the summer, winter, and cold wave periods. The first is from 1 May to 31 October, the second is from 1 November to 30 April, while the third has... 

I. Hydrolysis by sodium hydroxide. Classes (B), (C) and (D) hydrolyse thus ... 

Measurement Errors for Class A Glassware Class B Glassware... 

Specifications for class A and class B glassware are taken from American Society for Testing and Materials E288, E542 and E694 standards. 

Although the charcoal canisters are about 95% effective, fuel volatiUty still impacts the mass of vapors that break through the canister. Therefore, EPA mandated that starting in the summer of 1992, RVP levels be reduced below the levels specified in ASTM D4814. Class C regions, generally the northern part of the country, are limited to a maximum RVP of 62 kPa (9.0 psi) vs an ASTM limit of 79 kPa (11 psi), and the southern Class B regions are limited to a maximum RVP of 54 kPa (7.8 psi) vs 69 kPa (9.0 psi) for ASTM. 

Gold Compounds. The chemistry of nonmetallic gold is predominandy that of Au(I) and Au(III) compounds and complexes. In the former, coordination number two and linear stereochemistry are most common. The majority of known Au(III) compounds are four coordinate and have square planar configurations. In both of these common oxidation states, gold preferably bonds to large polarizable ligands and, therefore, is termed a class b metal or soft acid. 

With respect to the hazards of fire and explosion, nitrobenzene is classified as a moderate hazard when exposed to heat or flame. Nitrobenzene is classified by the ICC as a Class-B poisonous Hquid. 

Health nd Safety Factors. The mononitrochlorobenzenes are toxic substances which may be absorbed through the skin and lungs giving rise to methemoglobin. Their toxicity is about the same as or greater than that of nitrobenzene. The para isomer is less toxic than the ortho isomer, and the maximum allowable concentration that has been adopted for -nitrochlorobenzene is 1 mg/m (0.1 ppm) (6). The mononitrochlorobenzenes are moderate fire hazards when exposed to heat or flame. They ate classified by the ICC as Class-B poisons. The same handling precautions should be used for these compounds as are used for nitrobenzene. 

Low Level Waste. The NRC 10CFR61 specifies the nature of the protection required for waste containers (20). Class A wastes must meet minimum standards, including no use of cardboard, wastes must be solidified, have less than 1% Hquid, and not be combustible, corrosive, or explosive. Class B wastes must meet the minimum standards but also have stabiHty, ie, these must retain size and shape under soil weight, and not be influenced by moisture or radiation. Class C wastes must be isolated from a potential inadvertent intmder, ie, one who uses unrestricted land for a home or farm. Institutional control of a disposal faciHty for 100 years after closure is requited. 

The three classes of PE, designated as A, B, and C, specify the color, amount, and type of antioxidants and other additives. Class A refers to naturally colored PE, Class B includes white or black polymer, and Class C covers weather-resistant black polymer containing no less than 2% carbon black. Typical characteristics of resins used for film manufacture, injection mol ding, and blow mol ding are given in Table 5. 

Portable fire extinguishers are classified according to appHcabiHty Class A for soHd combustibles Class B for flammable Hquids Class C for electrical fires that require a nonconducting agent and Class D for combustible metals. Water frequently is used for Class A extinguishers bicarbonates for Class B and Class BC carbon dioxide or Freon for Class C ammonium phosphate for Class ABC and powdered salt, sodium chloride, for Class D. 

According to one classification (15,16), symmetrical dinuclear PMDs can be divided into two classes, A and B, with respect to the symmetry of the frontier molecular orbital (MO). Thus, the lowest unoccupied MO (LUMO) of class-A dyes is antisymmetrical and the highest occupied MO (HOMO) is symmetrical, and the TT-system contains an odd number of TT-electron pairs. On the other hand, the frontier MO symmetry of class-B dyes is the opposite, and the molecule has an even number of TT-electron pairs. 

Aniline is shipped in tank tmck and tank car quantities and is classified by the U.S. Department of Transportation (DOT) as a Class B poison (UN 1547), and must carry a poison label. 

Wa.ter Qua.litySta.nda.rds, The first step in water quahty standards is stream use classification. The individual states must decide what the uses of their water will be. The four categories, as defined by the EPA, are Class A, primary water contact recreation Class B, propagation of desirable aquatic life Class C, pubHc water suppHes prior to treatment and Class D, agricultural and industrial uses. States may vary the definition of these classes to meet their own needs. The second step is to develop water-quaHty criteria. This is the specific concentration of a pollutant that is allowable for the designated use. 

Shipment nd Stora.ge, Sulfur monochloride is minimally corrosive to carbon steel and iron when dry. If it is necessary to avoid discoloration caused by iron sulfide formation or chloride stress cracking, 310 stainless steel should be used. Sulfur monochloride is shipped in tank cars, tank tmcks, and steel dmms. When wet, it behaves like hydrochloric acid and attacks steel, cast iron, aluminum, stainless steels, copper and copper alloys, and many nickel-based materials. Alloys of 62 Ni—28 Mo and 54 Ni—15 Cr—16 Mo are useful under these conditions. Under DOT HM-181 sulfur monochloride is classified as a Poison Inhalation Hazard (PIH) Zone B, as well as a Corrosive Material (DOT Hazard Class B). Shipment information is available (140). 

Some friction materials may contain other potentially harmfiil materials. Lead has been found in some secondary linings. Class B and C organic disk pads, and other friction materials as lead metallic particles, oxides, and sulfides. Several original equipment and aftermarket suppHers are known to have a pohcy against incorporation of lead or other potentially harmfiil materials in thek products. 

Methyl bromide is sold both as the essentially pure compound, 99.5% minimum, with not more than 0.010% water and 0.001% acidity as HBr, and with small amounts of chloropicrin [76-06-2], CCI2NO2. During 1992 methyl bromide in tank cars was priced at 1.70/kg. Methyl bromide is suppHed in 37,850- and 60,560-L tank cars and in 12,220-L ISO cylinders. Repackagers supply methyl bromide in 0.45 kg or 0.68 kg cans for such appHcations as fumigating tobacco seed beds. Alone or in formulations, it is classified as a poison, class B, and requires a poison label. 

Attempts have been made to categorize the interactions between metal ions and ligands. Whereas all metal ions interact more strongly with fluoride than with chloride in the gas phase, in aqueous solution a number of exceptions occur. Metal ions that have the normal (class a) aqueous solution stabiUty order of F Cl > Br > I also have N P > As > Sb and 0 S > Se > Te donor stabiUty order (13). The inverse (class b) aqueous solution stabiUty... 

Bases of low polarizabiUty such as fluoride and the oxygen donors are termed hard bases. The corresponding class a cations are called hard acids the class b acids and the polarizable bases are termed soft acids and soft bases, respectively. The general rule that hard prefers hard and soft prefers soft prevails. A classification is given in Table 3. Whereas the divisions are arbitrary, the trends are important. Attempts to provide quantitative gradations of "hardness and softness" have appeared (14). Another generaUty is the usual increase in stabiUty constants for divalent 3t5 ions that occurs across the row of the Periodic Table through copper and then decreases for zinc (15). 

Class B direct dyes have poor leveling power and exhaustion must be brought about by controlled salt addition. If these dyes are not taken up uniformly in the initial stages it is extremely difficult to correct the urdevelness. They are dyes that have medium—high affinity and poor diffusion. In their apphcation the cellulose is entered into a dyebath containing ordy dye. The salt is added gradually and portionwise as the temperature is increased and possibly the final additions made after the dyebath has come to the bod. 

Of the mesolonic systems, (40) and its aza derivatives (43), (44) and (49) have been designated as Class B by Ollls (76AHC(l9)i), including compounds with X = CRR there... 

The mesoionic compounds are derived from pyrazolium salts (22) when R is replaced by a negatively charged heteroatom, like the anhydro-4-hydroxypyrazolium hydroxide (28). According to Ollis and Ramsden (76AHC(l9)l) they belong to the mesoionic class B type. 

Class B—Non-IDLH based on oxygen level between 19.5 and 21 percent, but classified as dangerous due to the airborne presence of toxic or poisonous substance Below IDLH level, but greater than the protection factor offered by air-purifying respirators. 

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