Method precision determination

The large temperature difference of the remarkable borehole, opposite other boreholes and their environment is significant. This high temperature difference is a typical feature for a small wall thickness between borehole and blade surface. For technical reasons, precise eroding of the boreholes is difficult. Due to this, the remaining wallthickness between the boreholes and the blade surface has to be determined, in order to prevent an early failure, Siemens/Kwu developed a new method to determine the wallthickness with Impulse-Video-Thermography [5],... 

An analytical procedure is often tested on materials of known composition. These materials may be pure substances, standard samples, or materials analyzed by some other more accurate method. Repeated determinations on a known material furnish data for both an estimate of the precision and a test for the presence of a constant error in the results. The standard deviation is found from Equation 12 (with the known composition replacing /x). A calculated value for t (Eq. 14) in excess of the appropriate value in Table 2.27 is interpreted as evidence of the presence of a constant error at the indicated level of significance. 

Analysis of Duplicate Samples An effective method for determining the precision of an analysis is to analyze duplicate samples. In most cases the duplicate samples are taken from a single gross sample (also called a split sample), although in some cases the duplicates must be independently collected gross samples. The results from the duplicate samples, Xi and X2, are evaluated by determining the difference, d, or the relative difference, d) between the samples... 

This contrasts with a limiting ratio of 2 for the case of termination by disproportionation. Since and can be measured, this difference is potentially a method for determining the mode of termination in a polymer system. In most instances, however, termination occurs by some proportion of both modes. Although general expressions exist for the various averages and their ratio when both modes of termination are operative, molecular weight data are generally not sufficiently precise to allow the proportions of termination modes to be determined in this way. 

Size. The precise determination of particle size, usually referred to as the particle diameter, can actually be made only for spherical particles. For any other particle shape, a precise determination is practically impossible and particle size represents an approximation only, based on an agreement between producer and consumer with respect to the testing methods (see Size measurement of particles). 

Selection of appropriate time intei vals for increment extractions relates to property variation (inhomogeneity) within material flow streams. Ten minute extraction intei vals are generally adequate to obtain suitably representative samples from material flows under practical circumstances. Precise determination of extraction intei vals consistent with individual apphcations can be calculatedthrough autocorrelation of historical sampling data, a statistical method described in references (Gy, Pitard). 

The abundance of a trace element is often too small to be accurately quantihed using conventional analytical methods such as ion chromatography or mass spectrometry. It is possible, however, to precisely determine very low concentrations of a constituent by measuring its radioactive decay properties. In order to understand how U-Th series radionuclides can provide such low-level tracer information, a brief review of the basic principles of radioactive decay and the application of these radionuclides as geochronological tools is useful. " The U-Th decay series together consist of 36 radionuclides that are isotopes (same atomic number, Z, different atomic mass, M) of 10 distinct elements (Figure 1). Some of these are very short-lived (tj j 1 -nd are thus not directly useful as marine tracers. It is the other radioisotopes with half-lives greater than 1 day that are most useful and are the focus of this chapter. 

It is apparent (Fig. 1.21) that at potentials removed from the equilibrium potential see equation 1.30) the rate of charge transfer of (a) silver cations from the metal to the solution (anodic reaction), (b) silver aquo cations from the solution to the metal (cathodic reaction) and (c) electrons through the metallic circuit from anode to cathode, are equal, so that any one may be used to evaluate the rates of the others. The rate is most conveniently determined from the rate of transfer of electrons in the metallic circuit (the current 1) by means of an ammeter, and if / is maintained constant it can eilso be used to eveduate the extent. A more precise method of determining the quantity of charge transferred is the coulometer, in which the extent of a single well-defined reaction is determined accurately, e.g. by the quantity of metal electrodeposited, by the volume of gas evolved, etc. The reaction Ag (aq.) -t- e = Ag is utilised in the silver coulometer, and provides one of the most accurate methods of determining the extent of charge transfer. 

To measure the strength of the forces exerted on particles, various analytical techniques have been developed [6, 7]. Unfortunately, since most of these techniques are based on hydrodynamics, assumption of the potential profiles is required and the viscosities of the fiuid and the particle sizes must be precisely determined in separate experiments, for example, using the viscous flow technique [8,9] and power spectrum analysis of position fluctuation [10]. Furthermore, these methods provide information on ensemble averages for a mass of many particles. The sizes, shapes, and physical and chemical properties of individual particles may be different from each other, which will result in a variety of force strengths. Thus, single-particle... 

Potassium is abundant in animal and plant cells (Birch and Pradgeham 1994). Hypokalemia (deficiency) and hyperkalemia (accumulation of K[I]) may both occur. As the normal range of K[I] in plasma is small, and the consequences of hyperkalemia fatal, the method of determination must be precise and accurate to detect lower and higher than normal levels (hypokalemia and hyperkalemia, respectively). The preferred method of determination is PISE. 

For the purpose of precise determination of the electric quadmpole interaction of ZnO, Perlow et al. [59] applied the method of frequency... 

On occasion, results from one of the participating laboratories will fail to meet established acceptability criteria. In those cases, acceptance or rejection of the method is determined by the CVM based on overall method performance. For example, a method that has borderline but acceptable performance for both precision and accuracy at two of three participating laboratories and fails badly at a third laboratory would probably fail. A method that was a borderline failure in one laboratory but easily passed in the other laboratories could be accepted. 

The accuracy and precision of the analytical methods were determined by the average and standard deviation of individual method recoveries of the fortitied-control samples in 50 different matrices (see Tables 1 and 2). These methods were also demonstrated to be very rugged based on the results of accuracy and precision for a variety of crop and animal matrices. 

Methods for Determining Biomarkers of Exposure and Effect. Analytical methods with satisfactory sensitivity and precision are available to determine the levels of americium in human tissues and body fluids. However, improved methods are needed to assess the biological effects of americium in tissues. 

The oxidation reaction proceeds to completion within 30 to 40 min the oxidant consumed is precisely determined on an excess of reagent by means of an iodometric procedure. Polyethylene samples containing varying amounts of 4,4/-thiobis(6-f-butyl-m-cresol) and other synergists were analysed with results close to the expected values. The method has been applied to numerous commercially available polymers. 

A way to increase the precision of the value Mw/Mn extracted from DLS is to consider several correlation functions and to look for a single answer. Stepanek [50] developed a method to determine the polydispersity of polymer samples with narrow distribution by measuring several correlation functions with different sample times on a linear correlator. With this procedure polydispersities in the range Mw/Mn — 1.05 — 2 can be determined. 

Precision determinations of wc by means of WAXS measurements are carried out by the Ruland [14] method. The method is sufficiently described in textbooks [7, 22], A modified version adapted to automatic processing by a computer has been introduced by Vonk [108],... 

---