Reliability of Method

We both felt from the beginning of our co-operation that we should spend a significant part of our scientific life to the improvement of analytical science, particu-lary the reliability of methods . 

Values for RU differed by up to 100% with 1,4-DVB-microgels [286]. The reliability of methods for determining the RU of 1,4-DVB-microgels was checked [287] with poly(4-vinylstyrene) which was prepared by anionic polymerization of 1,4-DVB (Table 3). From these results, it can be concluded that only quantitative IR-spectroscopy is a reliable method for determining the RU of 1,4-DVB-... 

Considering the importance of system suitability in determining the accuracy and reliability of method results, it is improper to set an RSD requirement of < 2% for a method that consistently yields values of < 1%. If peak tailing is always < 1.5, then a requirement of < 2.0 does not provide feedback to notify the chemist of a poor or failing column. Resolution requirements must be required for the critical pair of components where a loss of resolution would impact method performance. By addressing these parameters with a more critical eye, the suitability of the analysis system can be accurately determined. 

The usefulness of a methodology manual is in no small way directly related to the reliability of methods described. It is therefore preferable that methods selected for inclusion therein be tested and satisfactory performance demonstrated. This criterion was assumed to be met by selecting methods from the following sources, listed in order of estimated decreasing reliability official methodology manuals with method subjected to interlaboratory validation > other methodology manuals > literature and independently confirmed by other laboratories > unconfirmed reports in the literature. Due to the relatively small number of validated AAS methods, and the... 

In the matter of standards, intelligent skepticism is essential for reliable work every experienced chemist is cautious about accepting claims regarding the reliability of methods and applicability of materials. 

We have demonstrated chemical agent detection using accurately binary phase-shaped femtosecond pulses in the laboratory environment. Increase in multidimensionality has shown to improve the reliability of method. Future efforts will be focused on ambient sampling and expansion of database. Graphical user interface of the detection software is shown here (Figure 5) for a set of chemical agent simulants currently in the database. 

Exposure. Methods for the detennination of formaldehyde in blood (Heck et al. 1985), breath (Lin et al. 1995), and urine (Shara et al. 1992) have been published. However, formaldehyde concentration in body fluids or expired air is not expected to be a reliable biomarker of exposure, even for acute exposure, because of its high reactivity and rapid metabolism. Methods for the detection of formate, the principal metabolite of formaldehyde, in urine are also available, but urinary levels of formate did not appear to be consistently associated with exposure levels in studies of students exposed to formaldehyde in anatomy laboratories (Einbrodt et al. 1976 Gottschling et al. 1984). One plausible contributing factor to the lack of consistency in the use of fonnate concentrations as a measure of exposure is that the metabolism of other chemicals can lead to die formation of formate. Further research to increase the sensitivity or reliability of methods to quantify formaldehyde or formate does not seem warranted. 

The reliability of method for electronic structure calculations and models used in zeolite modeling is briefly reviewed. Only traditional ab initio methods and methods based on the density functional theory are discussed. Periodic, cluster, and combined models are described and their suitability for investigation of various properties is discussed. This contribution is written for non-experts in computational chemistry. The author hopes that it will help them to gain a basic orientation in the field. 

The efficiency and reliability of methods and methodical support of EAC system are dependent on the extent of reliability in the process to sampling and preparing samples. The equipment used for sampling, sample preparation, and determination both in the field and for industrial purposes must work independently in the wide range of temperatures (from -50 to +50 C) and humidity and endure aggressive influence of environment. The ways of sampling are dependent on the phase state of a sample, nature of determined components, and peculiarities of determination methods applied. Generally, it is advisable to... 

The offered method has allowed essentially to simplify the X-ray apparatus main circuit, to reduce weight and dimensions of the apparatus, to increase sensitivity and reliability of the inspection and to ensure the apparatus control by a computer The main principle is based on the operation of the transformer controlled by magnetic commutation (TCMC). 

The method was applied for determination of the quality of the detection media on test pieces following the type testing of the European standard [4] in order to check the validity of the method. The other application was the determination of the visibility in dependance of the variations of the inspection parameters (application of the detection medium, magnetization, inclination, viewing conditions) in a range which may appear in the practical inspections. The results leads to conclusions on the visibility level which is a measure of the probability of recognition for the indication that means of the reliability of the method. 

Therefore, it is important for judging the performance and the safety of the product to understand the size of the defect and the position by the ultrasonic method quantitatively. And, the reliability of the product improves further by feeding back this ultrasonic wave information to the manufacturing process. 

Attestation of the test procedure is realized with the aim to confirm both the correctness of the choice of method and NDT facilities and fullness of requirements included in the test procedure. Attestation ensures reliability of testing results with required accuracy. 

The procedure of testing must include measurements which have to provide reliable information about the quality of the object to be tested. The list of characteristics of measurement errors is selected on the basis of the required end results, methods of its calculation, form of presentation of the accuracy factors, reliability of the end result. These factors are of utmost attention in attestation of the procedure of testing. 

Naohtigall P, Jordan K D, Smith A and J0nsson FI 1996 Investigation of the reliability of density funotional methods reaotion and aotivation energies for Si-Si bond oleavage and FI2 elimination from silanes J. Chem. Phys. 104 148-58... 

By applying this method, they demonstrated that the removal of insignificant variables increases the quality and reliability of the models despite the fact that the correlation coefficient, r, always decreases, although only shghtly. For example, the characteristics of a model with six orthogonalized descriptors were r = 0.99288, s = 0.9062, F = 127.4 and the quality of this model was sufficiently improved after removal of the two least significant descriptors, to r = 0.9925, s = 0.8553,... 

There are three modihed intermediate neglect of differential overlap (MINDO) methods MINDO/1, MINDO/2, and MINDO/3. The MINDO/3 method is by far the most reliable of these. This method has yielded qualitative results for organic molecules. However its use today has been superseded by that of more accurate methods such as Austin model 1 (AMI) and parameterization method 3 (PM3). MINDO/3 is still sometimes used to obtain an initial guess for ah initio calculations. 

Completely ah initio predictions can be more accurate than any experimental result currently available. This is only true of properties that depend on the behavior of isolated molecules. Colligative properties, which are due to the interaction between molecules, can be computed more reliably with methods based on thermodynamics, statistical mechanics, structure-activity relationships, or completely empirical group additivity methods. 

You can investigate the energetics of chemical equilibrium by comparing the heats of formation of reactants and products. This produces one of the most useful results of a chemical calculation. The accuracy and reliability of the heats of formation depend on the method used (see Choosing a Semi-Empirical Method on page 148). 

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