Origination standards

These delta values (read delta C-13 , or delta carbon-13 ) are typically given in parts per thousand ( permil , %o). For historical reasons, carbon stable isotopes are reported relative to the PDB (Pee Dee Belemnite, a fossil) or the equivalent VPDB (Vienna PDB) standard. Oxygen and hydrogen stable isotopes are reported relative to SMOW (Standard Mean Ocean Water) or the equivalent VSMOW (Vienna SMOW). The VPDB and VSMOW standards are preferred, not only because the original standards, PDB and SMOW, are no longer available, but also because they imply that the measurements have been calibrated according to international conventions. 

You decide to do windowing on a C18 SFE cartridge column. You take a mixture of the four original standards, dilute it 5-fold with water to increase the compound s k s, and pass it through the MeOH and water-wetted SPE... 

Moore and Stein s original standard 1951 technique involves the use of 100 X 0.9 and 15 X 0.9-cm columns. Huisman (H27) uses the original technique, whereas van der Schaaf and Huisman (V2) have used 30 X 0.9-cm columns. Evered (E5) uses the technique with Dowex 50-X12 for urine analysis. His chromatograms are similar to those obtained with Dowex 50-X8. They show poor results in the separation of... 

The original standard military propellant. Now obsolete for this purpose. 

Based on biological assay in vitamin E-deficient rats, the vitamers have widely varying biological activity. The original international unit (iu) of vitamin E potency was equated with the activity of 1 mg of (synthetic) dl- -tocopherol acetate on this basis, pure D-a-tocopherol (i i i -a-tocopherol, the most potent vitamer) is 1.49 iu per mg. The precise mixture of stereoisomers in this original standard is unknown, and the different stereoisomers have very different biological activities, so that different preparations may differ considerably. 

Shutoff (leakage) classes for valves, standardized in 1976 by ANSI B16.104, are summarized in the table. (See the original standard for test media, pressures and required procedures.) These classifications should be familiar to anyone concerned with valves, whether for... 

According to the Food Drug Administration, the food can be called Reduced Fat if the oil content is reduced by 33 1/3% of the original (standard) level. Low-oil potato chips are made using the following steps ... 

One of the first apphcations of the paleotemperature method was undertaken by Harold Urey et al. (1951), who analyzed incremental sections along the radius of the shell of a fossil belemnite (a type of cephalopod). This bullet-shaped shell, from the Cretaceous PeeDee formation of South Carolina, was the original standard material for 5 C analysis (Table 5.2). The isotopic diary of the PeeDee belemnite (Fig. 5.4) records four cool extremes separated by three warm periods, in what appears to be 3.5 y of life history laid down approximately sixty million years ago. The absolute temperature scale is uncertain, because the 5 0 of the ancient sea where the belemnite lived is unknown. 

Two power function graphs are necessary, one to describe the performance for random error (RE) and the other for the performance for systematic error. For RE, as shown in Figure 19-10, A, the x-axis is labeled ARE. A value of 1.0 corresponds with the original standard deviation of the analytical method, a value of 2.0 to a doubling of that standard deviation, 3.0 to a tripling, and so on. For systematic error (SE), the x-axis is labeled ASE (see Figure 19-10, B). A value of 1.0s corresponds to a systematic shift equivalent to the size of the standard deviation, a value of 2.0 s to a shift equivalent to two times s, and so on. 

The original standard bench-scale kettle was a 600-ml stainless-steel beaker, temperature was controlled by immersion in a water bath, and agitation was effected with a 2-in.-wide, oval-shaped, flat-bladed, air-driven stirrer. Operations were performed semiremotely behind a shield in a fume hood. However, considerable exposure of the operator s hands and forearms took place even when tongs and other tools were used. 

Each Hardgrove machine is calibrated with standard reference samples of coal of grindability indices 40, 60, 80 and 110 which are obtainable from the US Bureau of Mines in Pittsburgh or other sources. The index is determined from the amount of fines formed if a standard sample weight (50 g) is subjected to standard grinding conditions. The harder is the coal, the lower is the index number, with 100 corresponding to an original standard soft coal. 

---