Procedures standard

It is important to eliminate the water of the hydrated sodium sulfide for producing a proper sulfidizing agent. Sodium sulfide nonahydrate is dehydrated by means of distillation in a large amount of an organic amide solvent. In practice, the water content is 0.8-1.2 molmol of alkali metal 

The time of synthesis of the polymer can be shortened by reducing either the time of water elimination of the sulfide compound and by the acceleration of the rate of polymerization by the choice of proper polymerization catalysts. 

Suitable polymerization catalysts are organic metal carboxylates. Lithium salts are highly soluble in the reaction system and large in the catal5 ic effect, but expensive. Potassium, rubidium, cesium, and alkatine earth metal salts are considered poorly soluble in the reaction system. Sodium salts can preferably be used since they are cheap and moderately soluble in the polymerization system. Thus, sodium acetate is a preferred catalyst. Another class of catalysts are cyclic amine compounds, A-heteroaromatic compounds, and organic sulfoxide compounds. 

The effect of lithium as a catalyst is illustrated in Table 5.2. Both polymers in Table 5.2 are prepared in a nearly similar manner. The dehydration is done for 50 min to a final temperature of 210-220°C. The molar ratio of catalyst to sulfur compound is adjusted to 0.60. A final temperature 

Molar Ratio H2O/S Catalyst Melt Flow Rate  

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There are two standard procedures for determining the octane numbers Research or FI and the Motor or F2 methods. The corresponding numbers are designated as RON (Research Octane Number) and MON (Motor Octane Number) which have become the international standard. 

This rule is justified by the need to limit the benzene emissions from evaporation (Tims, 1983) Figure 5.25 shows that emissions increase linearly with the benzene content of the fuel. It is noteworthy that current legislation limits the measured evaporation to 2 g per test conducted in accordance with a standard procedure (Sealed Housing for Evaporative Determination, or SHED). Yet for a fuel containing 5% benzene, an evaporation of 0.7 g benzene /test is observed. 

Standard procedures that are used for testing of construction materials are based on square pulse actions or their various combinations. For example, small cyclic loads are used for forecast of durability and failure of materials. It is possible to apply analytical description of various types of loads as IN actions in time and frequency domains and use them as analytical deterministic models. Noise N(t) action as a rule is represented by stochastic model. 

If GOST doesn t cover conerete requirements for the regime of testing, the procedure may be adopted as standard procedure and in this case the technological instruction with relevant missing aspects has to be developed on the basis of this GOST. This standard procedure must be approved by technical manager of the firm. 

I.P.P.D and its relatives have become standard procedures for the characterization of the structure of both clean surfaces and those having an adsorbed layer. Somoijai and co-workers have tabulated thousands of LEED structures [75], for example. If an adsorbate is present, the substrate surface structure may be altered, or reconstructed, as illustrated in Fig. VIII-9 for the case of H atoms on a Ni(llO) surface. Beginning with the (experimentally) hypothetical case of (100) Ar surfaces. Burton and Jura [76] estimated theoretically the free energy for a surface transition from a (1 x 1) to a C(2x 1) structure as given by... 

Consider a system of N particles in d dimensions. Using the standard procedure of integrating over the momenta in Cartesian coordinates, we can write the average of a mechanical property A(r ) as... 

Standard procedures for the derivation of the shape functions of common types of finite elements can be illustrated in the context of two-dimensional triangular and rectangular elements. Let us, first, consider a triangular element having three nodes located at its vertices as is shown in Figure 2.6. 

X = Cl, 0-tetrahydropyranyl, 0-CH(CH3)OCjH5 The starting compounds can be easily synthesized by standard procedures in acetylene chemistry. 

For several standard procedures no references are given. They can be easily located in M. Fieser and... 

By following the standard procedures of statistical mechanics, one arrives at an equation which can be converted into the BET equation (2.12) by the simple substitution 9i/9i , ki = c. Thus parameter c acquires a significance different from that in the BET theory in essence it now involves entropic terms as well as energetic terms. 

The standard procedure is to measure D at several different initial concentrations, using the procedure just described, and then extrapolating the results to c = 0. We symbolize the resulting limiting value D°. This value can be interpreted in terms of Eq. (9.79), which is derived by assuming 7 -> 1 and therefore requires extreme dilution. It is apparent from Eqs. (9.79) and (9.5) that D° depends on the ratio T/770, as well as on the properties of the solute itself. In order to reduce experimental (subscript ex) values of D° to some standard condition (subscript s), it is conventional to write... 

Oxygen transfer rate (OTR) is estimated by the foUowiag standard procedure (12), where the rate of mass transfer per unit volume of Hquid is taken to be directly proportional to the driving force of the system... 

The type of food and its processing affect flavoring efficiency therefore, flavor materials must be taste-tested in the food itself. Because there has been a lack of standardization of testing techniques, a committee on sensory evaluation of the Institute of Food Technologists has offered a guide (112) which is designed to help in developing standard procedures. 

C, which decomposes when heated above the melting point. Its solubility at 25°C in g/100 g solvent is water. 111 methanol, 5 ethanol, 1.4 acetone, 0.04 and carbon tetrachloride, 0.004. Because its carbon—fluorine bond is unreactive under most conditions, this salt can be converted by standard procedures to typical carboxylic acid derivatives such as fluoroacetyl esters (11,12), fluoroacetyl chloride [359-06-8] (13), fluoroacetamide (14), or fluoroacetonitrile [503-20-8] (14). 

Industry has standardized procedures for the quantitative sensory assessment of the perceived olfactory intensity of indoor malodors and their relationship to the deodorant efficacy of air freshener products. Synthetic malodors are used for these evaluation purposes. These malodors should be hedonicaHy associated to the "real" malodor, and must be readily available and of consistent odor quaUty. These malodors should be tested in various concentrations and be representative of intensities experienced under normal domestic conditions. 

The hberated iodine, as the complex triiodide ion, may be titrated with standard thiosulfate solution. A general iodometric assay method for organic peroxides has been pubUshed (253). Some peroxyesters may be determined by ferric ion-catalyzed iodometric analysis or by cupric ion catalysis. The latter has become an ASTM Standard procedure (254). Other reducing agents are ferrous, titanous, chromous, staimous, and arsenite ions triphenylphosphine diphenyl sulfide and triphenjiarsine (255,256). 

Components of sodium sulfates are easy to analyze using standard procedures. Except for normal analytical care in handling samples, no special precautions or procedures are required. 

Ash and Inorganic Constituents. Ash may be measured gravimetdcaHy by incineration in the presence of sulfudc acid or, more conveniendy, by conductivity measurement. The gravimetric result is called the sulfated ash. The older carbonate ash method is no longer in use. Ash content of sugar and sugar products is approximated by solution conductivity measurements using standardized procedures and conversion factors. 

Nonwoven fabrics are generally described by the method of production, eg, needle-punched or spun-bonded (120). ASTM D1117 discusses various physical properties to be deterrnined for nonwoven fabrics and the standard procedures used. 

Acylation. To achieve acylation of thiophenes, acid anhydrides with phosphoric acid, iodine, or other catalysts have been widely used. Acid chlorides with AlCl, SnCl, ZnCl2, and BF also give 2-thienylketones. AH reactions give between 0.5 and 2.0% of the 3-isomer. There has been much striving to find catalyst systems that minimize the 3-isomer content attempting to meet to customer specifications. The standard procedure for formylation is via the Vil smeier-H a ack reaction, using phosphoms o xycbl o ri de / /V, / V- dim e tb yl fo rm a m i de (POCl /DMF) or /V-m ethyl form an i1 i de. 

The industry operates by using standardized procedures for testing and characterizing materials. These procedures are pubHshed and updated by the American Society for Testing Materials in consultation with interested parties in the industry. 

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