The Standard Method

In the standard method for the solution of the nuclear time-dependent Schrodinger equation (TDSE), the wavefunction is expanded in a basis of time-independent functions called a primitive basis. Specifically, considering a molecule with / degrees of freedom (dofs), abasis of Nk, one-dimensional functions xjf ( ) with k= 1. / can be defined for each dof and the total nuclear wavefunction is expanded in the product basis composed of Hartree products of these one-dimensional functions 

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The criterion retained up to now in the specifications is not the true vapor pressure, but an associated value called the Reid vapor pressure, RVP. The procedure is to measure the relative pressure developed by the vapors from a sample of motor fuel put in a metallic cylinder at a temperature of 37.8°C. The variations characteristic of the standard method are around 15 millibar in repeatability and 25 millibar in reproducibility. 

In the standard method, the metal enclosure (called the air chamber) used to hold the hydrocarbon vapors is immersed in water before the test, then drained but not dried. This mode of operation, often designated as the wet bomb" is stipulated for all materials that are exclusively petroleum. But if the fuels contain alcohols or other organic products soluble in water, the apparatus must be dried in order that the vapors are not absorbed by the water on the walls. This technique is called the dry bomb" it results in RVP values higher by about 100 mbar for some oxygenated motor fuels. When examining the numerical results, it is thus important to know the technique employed. In any case, the dry bomb method is preferred. 

The water and sediment contents of crude oils is measured according to the standard methods NF M 07-020, ASTM D 96 and D 1796, which determine the volume of water and sediments separated from the crude by centrifuging in the presence of a solvent (toluene) and of a demulsifylng agent Table 8.13 gives the bottom sediment and water content of a few crude oils. 

Figure I represents a two-dimensional damage distribution of an impact in a 0/90° CFRP laminate of 3 mm thickness. Unlike in ultrasonic testing, which is usually the standard method for this problem, there is no shadowing effect on the successive layers by delamination echos. With the method of X-ray refraction the exact concentration of debonded fibers can be calculated for each position averaged over the wall thickness. Additionally the refraction allows the selection of the fiber orientation. The presented X-ray refraction topograph detects selectively debonded fibers of the 90° direction.

By the standard methods of statistical thermodynamics it is possible to derive for certain entropy changes general formulas that cannot be derived from the zeroth, first, and second laws of classical thermodynamics. In particular one can obtain formulae for entropy changes in highly di.sperse systems, for those in very cold systems, and for those associated, with the mixing ofvery similar substances. 

These are not essential if the acid and amine obtained on hydrolysis are crystalline but crystalline derivatives of the acid and amine can be prepared by the standard methods for acids (p. 349) and amines (pp. 374, 376) respectively. 

The method is general for all organic halogen compounds and is the standard method for almost all such compounds, except of course... 

Provided that the balance is functioning correctly, the main source of error is in the weights themselves these should be calibrated by one of the standard methods so that their relative values are known, and they should be carefully cleaned with tissue paper and checked from time to time. To make the best use of the balance, weighing should be carried out by the method of swings, but for this purpose it is necessary first to determine the sensitivity of the balance. 

As you are about to see, the standard methods for using the NaBH(OAc)3 catalyst call for it to be in a dried, powder form. Strike supposes the benzene in the above reaction can be distilled off to leave dry catalyst. But don t quote Strike on that Maybe it could be made in situ in the DCE solvent of the reaction to come (don t ask). Aw hell Just go and buy the shit ... 

In general ketones are more stable than their enol precursors and are the products actually isolated when alkynes undergo acid catalyzed hydration The standard method for alkyne hydration employs aqueous sulfuric acid as the reaction medium and mer cury(II) sulfate or mercury(II) oxide as a catalyst... 

It IS often necessary to prepare ketones by processes involving carbon-carbon bond formation In such cases the standard method combines addition of a Gngnard reagent to an aldehyde with oxidation of the resulting secondary alcohol... 

The reaction of an aryl diazonium salt with potassium iodide is the standard method for the preparation of aryl iodides The diazonium salt is prepared from a primary aro matic amine m the usual way a solution of potassium iodide is then added and the reac tion mixture is brought to room temperature or heated to accelerate the reaction... 

Reduction of aryl nitro compounds (Sec tion 22 9) The standard method for the preparation of an arylamine is by nitra tion of an aromatic ring followed by reduction of the nitro group Typical re ducing agents include iron or tin in hydro chloric acid or catalytic hydro genation... 

A major advance was devised by Pehr Edman (University of Lund Sweden) that has become the standard method for N terminal residue analysis The Edman degrada tion IS based on the chemistry shown m Figure 27 12 A peptide reacts with phenyl iso thiocyanate to give a phenylthwcarbamoyl (PTC) denvative as shown m the first step This PTC derivative is then treated with an acid m an anhydrous medium (Edman used mtromethane saturated with hydrogen chloride) to cleave the amide bond between the N terminal ammo acid and the remainder of the peptide No other peptide bonds are cleaved m this step as amide bond hydrolysis requires water When the PTC derivative IS treated with acid m an anhydrous medium the sulfur atom of the C=S unit acts as... 

Marecek and colleagues developed a new electrochemical method for the rapid quantitative analysis of the antibiotic monensin in the fermentation vats used during its production. The standard method for the analysis, which is based on a test for microbiological activity, is both difficult and time-consuming. As part of the study, samples taken at different times from a fermentation production vat were analyzed for the concentration of monensin using both the electrochemical and microbiological procedures. The results, in parts per thousand (ppt), are reported in the following table. 

Quantitative Analysis for a Single Analyte The concentration of a single analyte is determined by measuring the absorbance of the sample and applying Beer s law (equation 10.5) using any of the standardization methods described in Chapter 5. The most common methods are the normal calibration curve and the method of standard additions. Single-point standardizations also can be used, provided that the validity of Beer s law has been demonstrated. 

Since the junction potential is usually of unknown value, it is normally impossible to directly calculate the analyte s concentration using the Nernst equation. Quantitative analytical work is possible, however, using the standardization methods discussed in Chapter 5. 

Thus, the limiting current, is a linear function of the concentration of O in bulk solution, and a quantitative analysis is possible using any of the standardization methods discussed in Chapter 5. Equations similar to equation 11.35 can be developed for other forms of voltammetry, in which peak currents are related to the analyte s concentration in bulk solution. 

Analysis for Single Components The analysis of samples containing only a single electroactive analyte is straightforward. Any of the standardization methods discussed in Ghapter 5 can be used to establish the relationship between current and the concentration of analyte. 

Ruggedness testing is often performed by the laboratory developing the standard method. Potential factors are identified and their effects evaluated by performing the analysis while the factors are held at two levels. Normally one level for each factor is that given in the procedure, and the other is a level likely to be encountered when the procedure is used by other laboratories. 

A newly proposed method is to be tested for its singleoperator characteristics. To be competitive with the standard method, the new method must have a relative standard deviation of less than 10%, with a bias of less than 10%. To test the method, an analyst performs ten replicate analyses on a standard sample known to contain 1.30 ppm of the analyte. The results for the ten trials are... 

The above batch process has undergone numerous refinements to improve yields, processing characteristics, purity, and storage stabiUty, but it remains the standard method of manufacture for these products. Recentiy a continuous process has been reported by Bayer AG (6) wherein the condensation is carried out in an extmder. The by-products are removed in a degassing zone, and the molten polymer, mixed with stabilizers, is subsequendy cracked to yield raw monomer. 

The standard methods (26) of analysis for commercial lecithin, as embodied in the Official and Tentative Methods of the American Oil Chemists Society (AOCS), generally are used in the technical evaluation of lecithin (27). Eor example, the AOCS Ja 4-46 method determines the acetone-insoluble matter under the conditions of the test, free from sand, meal, and other petroleum ether-insoluble material. The phosphoHpids are included in the acetone-insoluble fraction. The substances insoluble in hexane are determined by method AOCS Ja 3-87. 

Various colorimetric methods have been employed for measuring ozone residuals, although most of these ate susceptible to significant interferences (142). The indigo trisulfonate method (143), however, has been approved by the Standard Methods Committee of the American Pubfle Health Association (141) and the International Ozone Association for ozone residual measurement. 

A.lkanolamine Process. Carbon dioxide is an acidic gas that reacts reversibly with aqueous alkaline solution to form a carbonate adduct. This adduct decomposes upon the addition of low level heat faciUtating CO2 removal. An aqueous solution of 15—20 wt % monoethanolamine (MEA) was the standard method for removing CO2 in early ammonia plants. 

AH glass capillary viscometers should be caUbrated carefully (21). The standard method is to determine the efflux time of distilled water at 20°C. Unfortunately, because of its low viscosity, water can be used only to standardize small capillary instmments. However, a caUbrated viscometer can be used to determine the viscosity of a higher viscosity Hquid, such as a mineral oil. This oil can then be used to caUbrate a viscometer with a larger capillary. Another method is to caUbrate directly with two or more certified standard oils differing in viscosity by a factor of approximately five. Such oils are useful for cahbrating virtually all types of viscometers. Because viscosity is temperature-dependent, particularly in the case of standard oils, temperature control must be extremely good for accurate caUbration. 

Quality Control. The spectrometer is the most suitable instmment for determining most low level residual impurities. ASTM E414 is the standard method for the measurement of impurities in copper by the briquette dc-arc technique (65). In this method, the sample in the form of chips, drillings, or powder is briquetted and excited in a d-c arc opposite a high purity copper rod. Impurities in the ranges noted can be measured ... 

Scheme 4 shows in a general manner cyclocondensations considered to involve reaction mechanisms in which nucleophilic heteroatoms condense with electrophilic carbonyl groups in a 1,3-relationship to each other. The standard method of preparation of pyrazoles involves such condensations (see Chapter 4.04). With hydrazine itself the question of regiospecificity in the condensation does not occur. However, with a monosubstituted hydrazine such as methylhydrazine and 4,4-dimethoxybutan-2-one (105) two products were obtained the 1,3-dimethylpyrazole (106) and the 1,5-dimethylpyrazole (107). Although Scheme 4 represents this type of reaction as a relatively straightforward process, it is considerably more complex and an appreciable effort has been expended on its study (77BSF1163). Details of these reactions and the possible variations of the procedure may be found in Chapter 4.04. 

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