Details of Calibration

There are many examples in our everyday life in which the calibration of a measuring device is important. When we step on the bathroom scale, we want to be assured that the scale reads our correct weight. When we measure the body temperature of our sick child, we want the temperature that is displayed to be correct. When we fill our car s gas tank at the gas pump, we want the pump to display the correct number of gallons and therefore the correct cost. In other words, we want these devices to be properly 

Steve Kruse of the City of Lincoln, Nebraska, Waste-water Treatment Plant Laboratory examines a faulty detector module taken from the flow injection analysis system in use in the laboratory. 

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Do the records include details of calibration controls, environmental data, designated error limits, and information necessary to establish traceability ... 

To put gap test results on a more absolute basis (so that comparisons can hopefully be made between various forms of the gap test as weil as with other shock sensitivity tests) it is necessary to calibrate the donor-gap system so that shock strengths are known as a function of barrier thickness. Details of calibration procedures are found in Refs 4 20a. If the shock Hugoniot of the unreacted test expl is known, the input shock in the test sample at the sample/barrier interface can be determined as discussed in Section II (Figs 1 2)... 

Measurements of the solid fat content are made by taking the amplitude of the FID at two times (typically 10 and 70 /is) following the 90° pulse. The first amplitude is proportional to the total number of protons (solid plus liquid phase) whereas the second amplitude depends only on the number of liquid-phase protons. The rapid decay of the solid-phase signal requires that a correction factor is determined to allow for the decay of the signal during the spectrometer dead-time. The correction factor is determined using calibration standards of known composition. Details of calibration methods, tempering procedures for fats and a comparison of NMR with other methods can be found in a review.22 Other publications in this area are listed in Table 8. 

An accurate dose calibrator is needed to assay the dosage of a PET radiopharmaceutical for administration to humans. The dose calibrator must be calibrated for constancy, accuracy, linearity, and geometry. The readers are referred to Saha (2004) for the details of calibration of the dose calibrator. 

D. Calibration made on an absolute scale for details of calibration, see Brice, Halwer and Speiser (1950). Molecular weights reported in this reference were determined also at 4358 A wiht results in close agreement with those at 5461 A. 

Kabo, F.G. and Diky, V.V., Details of calibration of a scamiing calorimeter of the triple heat bridge type, Thermochim. Acta., 2000, vol. 347, pp. 79-84. 

The standard requires the supplier to define the process employed for the calibration of inspection, measuring, and test equipment, including details of equipment type, unique identification, location, frequency of checks, check method, acceptance criteria, and the action to be taken when results are unsatisfactory. 

Details of any adjustments, servicing, repairs, and modifications carried out The name of the person performing the calibration Details of any limitation on its use... 

Before dealing with the experimental details of A AS or FES determinations it is necessary to consider the mode of treatment of the experimental data obtained. To convert the measured absorption values into the concentration of the substance being determined it is necessary either to make use of a calibration curve, or to carry out the standard addition procedure. 

Selectivity and Interference Selectivity means that only that species is measured which the analyst is looking for. A corollary is the absence of chemical interferents. A lack of selectivity is often the cause of nonlinearity of the calibration curve. Near infra-red spectroscopy is a technology that exemplifies how seemingly trivial details of the experimental set-up can frustrate an investigator s best intentions Ref. 124 discusses some factors that influence the result. 

Procedures should be established to periodically monitor all operations that may have an environmental impact, and similar scheduled periodic checks should be made to ensure that procedures and operations are still in line with regulatory and other requirements. If equipment is involved in the monitoring process then procedures should also be in place to ensure correct calibration. Procedures are also needed to record any preventative or corrective actions identified and to ensure that they are completed to schedule. The whole EMS should be audited periodically to check that it is consistent with the planned policy and has been properly implemented. The details of audits should be discussed and reviewed by management at the highest level with a view to continuous improvement through the modification of both policy and procedures. 

The model contains four parameters, the slope and intercept of the calibration line and two drift parameters a and p. All four parameters are estimated by applying the algorithm given in Table 41.10. Details of this procedure are given in Ref. [5]. 

The validation of calibration with CRMs is commonly performed by parallel application of independent methods, for details see below. 

Calibration data (e.g., linearity or sensitivity) are not discussed in detail between laboratories, but a typical calibration starts with 50% of the lowest fortification level and requires at least three additional calibration levels. Another point of calibration is the use of appropriate standards. In 1999 a collaborative study tested the effect of matrix residues in final extracts on the GC response of several pesticides.Five sample extracts (prepared for all participants in one laboratory using the German multi-residue procedure) and pure ethyl acetate were fortified with several pesticides. The GC response of all pesticides in all extracts was determined and compared with the response in the pure solvent. In total, 20 laboratories using 47 GC instruments... 

Updating of a calibration model in the case that details of the analytical procedure are changed. 

In connection with our field measurements, samples of geological materials were collected for analyses in the laboratory. Activity concentrations were measured by standard gamma spectrocqpy with a 90-cm3 Ge (Li) detector and a Canberra Model 8100 multichannel analyser. Details on calibration and procedure were published earlier (Stranden, 1985). Rn-222 exhalation measurements were also performed... 

Note that some organizations may not use the terminology used in this book and may not distinguish between SOPs and WIs. Standard Operating Procedures provide details of how a series of operations are carried out. An example of a SOP would be the detailed instruction for carrying out a particular analytical method. Work Instructions give details of how a specific operation is carried out. What might be classed as a WI is how to operate a particular instrument, how to estimate measurement uncertainty or how to calibrate a piece of equipment. 

One of the most interesting of the geophysics results from radiocarbon dates is the history of the sun. Apparently, it is registered in fluctuations of the cosmic ray intensity. These are fluctuations of rather short duration in terms of the radiocarbon lifetime, perhaps a century or so, and apparently they are caused by variations in the solar wind due to long-term changes in the solar emissions. This idea has been developed in some detail recently by Dr. Lai and his collaborators. It promises to give us a way of watching the history of the sun over tens of thousands of years. This fine structure on the curve of calibration was discovered by Dr. Suess and others. 

In those cases where concentrations are not measured directly, the problem of calibration of the in-situ technique becomes apparent. An assurance must be made that no additional effects are registered as systematic errors. Thus, for an isothermal reaction, calorimetry as a tool for kinetic analysis, heat of mixing and/or heat of phase transfer can systematically falsify the measurement. A detailed discussion of the method and possible error sources can be found in [34]. 

A combination of laboratory and field experiments is required for determination of components and parameters for a sewer process model for simulation of the microbial transformations of organic matter (cf. specifically Sections 5.2-5.4,6.3 and 6.4). Furthermore, additional information is needed to include the sulfide formation. Explicit determination of model components and parameters are preferred to indirect and implicit methods. However, to some extent, model calibration is typically needed to establish an acceptable balance between process details of a model and possibilities for direct experimental determination of model parameters. 

The replacement of OES by AAS in Oxford in 1976 immediately called into question the long-term compatibility of the huge analytical database amassed by OES with subsequent analytical techniques. Detailed intertechnique comparisons were carried out, both in Oxford (Hatcher et al. 1980) and elsewhere (White 1981). Both pointed toward the same conclusion OES data are generally more scattered, and systematic differences of calibration occur between OES and AAS. Hatcher et al. contemplated the use of... 

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