Results duplicate

Forty six field laboratories (mainly from France) have participated in the inter-laboratory comparison. They have analysed the water sample using their regular calibration solution and then have repeated this analysis using the certified standards. They also have analysed the matrix CRM. Laboratories have produced two results (duplicate) per sample. Techniques used were mainly atomic absorption spectroscopy with furnace but also ICP-OES and ICP-MS. 

To achieve accurate results, duplicate testing of samples is highly recommended. In addition, it will be necessary to dilute resuspended virus with high levels of RT activity because the ELISA method provides only a limited dynamic range. In some specimens, the resuspended virus contains inhibitors of the assay. To identify these specimens and to avoid significant underestimates of RT activity, a second set of reactions is run to which a defined amount of purified RT is added. 

Table 5.3 Determination of antibacterial activity—MIC and MBC results (Duplicates)...

In a book such as this it is impossible to avoid cross-references between chapters. However, it is equally difficult to ensure that such cross-references supply the answers expected of them. I have therefore attempted to make each chapter as free-standing as possible and have used the resulting duplications as a mechanism for deepening the discussion. This strategy can produce its own problems as well as benefits I hope that the index will provide direction to sufficient additional material to deal with the problems ... 

To chemically bond the polymer chains to the silicon surface the polymer brush samples required heat well above their Tg s. All samples were placed in a vacuum oven (25 Torr) at 170°C immediately following spin coating. The terminal OH groups reacted with the native oxide layer of the silicon wafer as demonstrated in literature. The reaction time was varied by removing samples from the high temperature environment at 10, 20, 40, 100, and 200 hours. (Because the 200 hour sample results duplicated the 100 hour sample results, only results for the 100 hour sample are presented.) To remove any unreacted polymer, the samples were immersed in toluene and placed in a sonicator for a total of 34 hours at approximately 40°C. 

Despite these similarities between the G2 calculations of Dg for H2 and Hj, there is a profound difference that is only hinted at in the single-point energies in Table 10-1. In the first group of results we see that all the calculations, with the exception of the last one, give the same answer. In the lower block of results, for H2, this is not the case. Some results are duplicated and some are not. The results are more mixed. 

Structure-property relationships are qualitative or quantitative empirically defined relationships between molecular structure and observed properties. In some cases, this may seem to duplicate statistical mechanical or quantum mechanical results. However, structure-property relationships need not be based on any rigorous theoretical principles. 

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... 

To evaluate the precision for the determination of potassium in blood serum, duplicate analyses were performed on six samples, yielding the following results. 

Agency. A second example of an external method of quality assessment is the voluntary participation of the laboratory in a collaborative test (Chapter 14) sponsored by a professional organization such as the Association of Official Analytical Chemists. Finally, individuals contracting with a laboratory can perform their own external quality assessment by submitting blind duplicate samples and blind standard samples to the laboratory for analysis. If the results for the quality assessment samples are unacceptable, then there is good reason to consider the results suspect for other samples provided by the laboratory. 

With a prescriptive approach to quality assessment, duplicate samples, blanks, standards, and spike recoveries are measured following a specific protocol. The result for each analysis is then compared with a single predetermined limit. If this limit is exceeded, an appropriate corrective action is taken. Prescriptive approaches to quality assurance are common for programs and laboratories subject to federal regulation. For example, the Food and Drug Administration (FDA) specifies quality assurance practices that must be followed by laboratories analyzing products regulated by the FDA. 

If the spike recovery for Bsf is acceptable, or if the result for sample B is below the method s detection limit or outside the range of 0.1 to 10 times the amount of analyte spiked in Bsf, then the duplicate samples Ai and A2 are analyzed. The results for Ai and A2 are discarded if the difference between their values is excessive. If the difference between the results for Ai and A2 is within the accepted limits, then the results for samples Ai and B are compared. Since samples collected from the same sampling site at the same time should be identical in composition, the results are discarded if the difference between their values is unsatisfactory, and accepted if the difference is satisfactory. 

The effect of impurities in either structural material or corrosive material is so marked (while at the same time it may be either accelerating or decelerating) that for rehable results the actual materials which it is proposed to use should be tested and not types of these materials. In other words, it is much more desirable to test the actual plant solution and the actual metal or nonmetal than to rely upon a duphcation of either. Since as little as 0.01 percent of certain organic compounds will reduce the rate of solution of steel in sulfuric acid 99.5 percent and 0.05 percent bismuth in lead will increase the rate of corrosion over 1000 percent under certain conditions, it can be seen how difficult it would be to attempt to duplicate here all the significant constituents. 

Probably the least appreciated weakness of QRA is that the results are difficult to duplicate by independent experts. Even with the variety of sophisticated tools available for use, QRA is still largely dependent on good engineering judgment. The subtle assumptions of analysts performing QRA studies can often be the driving force behind the results. Many times these assumptions are at best arguable, and at worst arbitrary. 

The yields reported were obtained using this stirrer with various other stirrers it was seldom possible to duplicate the results. 

Duplicate submissions not identified. Facilities sometimes send multiple copies of the same Form R report to insure that EPA received a copy. Duplicate submissions must be identified by printing the word DUPLICATE" in red Ink on page one in the box marked "THIS SPACE FOR YOUR OPTIONAL USE". Failure to clearly identity a duplicate report may result in the duplicate appearance of the data in the database and the appearance of increased emissions from the facility. 

Among the more exotic methods which have been used for the direct epoxidation of steroid olefins are chromic acid, ozone, e.g., (84), and photochemical oxygenation. Ozone is useful for the epoxidation of the unreactive 8,9-olefin, but the results of the other unusual methods can usually be duplicated by the methods of epoxidation discussed above. 

A realistic model of a solution requires at least several hundred solvent molecules. To prevent the outer solvent molecules from boiling off into space, and minimizing surface effects, periodic boundary conditions are normally employed. The solvent molecules are placed in a suitable box, often (but not necessarily) having a cubic geometry (it has been shown that simulation results using any of the five types of space filling polyhedra are equivalent ). This box is then duplicated in all directions, i.e. the central box is suiTounded by 26 identical cubes, which again is surrounded by 98 boxes etc. If a... 

The dynamic response used to describe fluid motion in the system is bulk velocity. Kinematic similarity exists with geom.etric similarity in turbulent agitation [32]. To duplicate a velocity in the kinematically similar system, the kno m velocity must be held constant, for example, the velocity of the tip speed of the impeller must be constant. Ultimately, the process result should be duplicated in the scaled-up design. Therefore, the geometric similarity goes a long way in achieving this for some processes, and the achievement of dynamic and/or kinematic similarity is sometimes not that essential. 

Because the most common impeller type is the turbine, most scale-up published studies have been devoted to that unit. Almost all scale-up situations require duplication of process results from the initial scale to the second scaled unit. Therefore, this is the objective of the outline to follow, from Reference [32]. The dynamic response is used as a reference for agitation/mixer behavior for a defined set of process results. For turbulent mixing, kinematic similarity occurs with geometric similarity, meaning fixed ratios exist between corresponding velocities. 

Fig. 1.49 Crevice corrosion, (a) Crevice resulting from the joining of two plates of steel and b) crevice due to a gasket between two flanged pipes (c), (d) and (e) show the method used by Streicher to test different steels for their propensity to crevice corrosion two plastic cylinders are held onto the sheet of metal by two rubber bands of the same size, giving rise to three different types of crevices in duplicate...

When the test is to be made to predict the performance of a material in a particular service, the ideal procedure would be to have the surface of the test-pieces duplicate the surface of the material as it would be used. Here, however, a complication is presented by the fact that materials in service are commonly used in several forms with different conditions of surface. Where the number of materials to be compared is large, it will usually be impractical to test all the conditions of surface treatment of possible interest. The best practical procedure, then, is to choose some condition of surface more or less arbitrarily selected to allow the materials to perform near the upper limits of their ability. If all the materials to be tested are treated in this way, and preferably with uniform surface treatment, the results of the test will indicate the relative abilities of the different materials to resist the test environment when in a satisfactory condition of surface treatment. Then, if it should be considered prudent or desirable to do so, the most promising materials can be subjected to further tests in a variety of surface conditions so that any surface sensitivity can be detected. 

Citing a number of earlier - and, in their opinion, unnecessarily complicated -research efforts to duplicate the characteristic spatial patterns of BZ-like reactions, Greenberg and Hastings wanted to construct a model that reproduced such patterns in the simplest possible manner, doing away with the need for extensive computation as the only means by which the desired results can be obtained. Previous studies. 

Once the best method of dealing with interferences has been decided upon and the most appropriate method of determination chosen, the analysis should be carried out in duplicate and preferably in triplicate. For simple classical determinations the experimental results must be recorded in the analyst s notebook. However, many modern instruments employed in instrumental methods of analysis are interfaced with computers and the analytical results may be displayed on a visual display unit, whilst a printer will provide a printout of the pertinent data which can be used as a permanent record. 

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