Applications test comparison

Further discussion of method validation can be found in Chapter 7. However, it should be noted from Table 11 that it is frequently desirable to perform validation experiments beyond ICH requirements. While ICH addresses specificity, accuracy, precision, detection limit, quantitation limit, linearity, and range, we have found it useful to additionally examine stability of solutions, reporting threshold, robustness (as detailed above), filtration, relative response factors (RRF), system suitability tests, and where applicable method comparison tests. 

The examples given here represent a small sample of potential applications. In test comparisons with some practicing engineers it was found that the strategy was useful in directing their attention to possible improvements that had not been obvious. 

Kahlenberg V (1999) Application and comparison of different tests on twiiming by merohedry. Acta Crystallogr Sect B-Struct Sci 55 745-751... 

Corrosion Testing Objectives of SCC testing are (i) determination of the risk of SCC for a given application and comparison of alloys (ii) examination of the effects of chemical composition, metallurgical processing, fabrication practices for structural components (iii) evaluation of protective systems and prediction of service life (iv) development of new alloys, which are less expensive, and offer a longer, safer, and efficient performance for chosen environments (v) evaluation of claims for SCC performance of improved mill products. 

Kallio, T., and A. Kaikkonen, 2005, Usability testing of mobile applications A comparison between laboratory and field testing. Journal of Usability Studies 1 (4-16) 23-28. 

Nitrile rubber containing the antioxidant specified in Fig. 3 exhibits improved oxygen absorption resistance both before and after methanol extraction (Fig. 4). This property has been confirmed in final product application testing where the non-volatility and non-extractability of the stabilizer guarantees a long-term antioxidant effect.A range of antioxidant-bound NBR polymers has now been commercialized and a comparison of the typical physical property differences of the medium-low acrylonitrile content polymer when compared with a conventional NBR is shown in Table 5. 

Exaggerated application tests are mainly used when several products have to be compared. Indeed, the development of consumer products with increased mildness renders product comparison very difficult in terms of skin irritation potential if test conditions do not enhance skin reactions. However, in order to evaluate an accurate tolerance of the product when it is launched in the marketplace, an in-use test in real-life conditions is much more appropriate to determine how product-skin compatibility will be perceived by the consumer. 

The correlation functions provide an alternate route to the equilibrium properties of classical fluids. In particular, the two-particle correlation fimction of a system with a pairwise additive potential detemrines all of its themiodynamic properties. It also detemrines the compressibility of systems witir even more complex tliree-body and higher-order interactions. The pair correlation fiinctions are easier to approximate than the PFs to which they are related they can also be obtained, in principle, from x-ray or neutron diffraction experiments. This provides a useful perspective of fluid stmcture, and enables Hamiltonian models and approximations for the equilibrium stmcture of fluids and solutions to be tested by direct comparison with the experimentally detennined correlation fiinctions. We discuss the basic relations for the correlation fiinctions in the canonical and grand canonical ensembles before considering applications to model systems. 

The applicability of the two-parameter equation and the constants devised by Brown to electrophilic aromatic substitutions was tested by plotting values of the partial rate factors for a reaction against the appropriate substituent constants. It was maintained that such comparisons yielded satisfactory linear correlations for the results of many electrophilic substitutions, the slopes of the correlations giving the values of the reaction constants. If the existence of linear free energy relationships in electrophilic aromatic substitutions were not in dispute, the above procedure would suffice, and the precision of the correlation would measure the usefulness of the p+cr+ equation. However, a point at issue was whether the effect of a substituent could be represented by a constant, or whether its nature depended on the specific reaction. To investigate the effect of a particular substituent in different reactions, the values for the various reactions of the logarithms of the partial rate factors for the substituent were plotted against the p+ values of the reactions. This procedure should show more readily whether the effect of a substituent depends on the reaction, in which case deviations from a hnear relationship would occur. It was concluded that any variation in substituent effects was random, and not a function of electron demand by the electrophile. ... 

Criteria 2 to 6 are pragmatic criteria which are only applicable to qualitative explanations. These criteria only give qualitative information which is dealt with further below (Section 3.3.3.1). Criterion 7 gives better information with potential test probes (see Section 3.3.3.2). In all the criteria it must be remembered that only mixed potentials can be measured for extended objects to be protected [see the explanation to Eqs. (3-19) and (3-28)]. Criteria 5 and 6 are particularly to be observed for objects [22]. A comparison of the different criteria in field experiments has shown that, besides Criterion 1, good results are obtained with Criterion 3 [26]. 

Tensile testing machine operated in a controlled temperature and humidity environment. Many applications involve bonding paper, which exhibits properties that are highly dependent on humidity. In addition, adhesive Tg values are often close to room temperature, and thus properties change substantially over even a few degrees. Therefore, for reproducible comparisons, temperature and humidity control is necessary. 

Claybrook, S 1992, Comparison of FTRIN Predictions to 1986 LLNL Enclosure Fire Tests 9 and 10, Numerical Applications Inc, Personal Communications. 

Field and Plant Tests Field exposure of test panels offers the benefit of a high degree of control over surface preparation and application. Moreover, through standardised exposure conditions, broader comparisons between both paint systems and locations are possible. More importantly, since replicates may be removed and laboratory tested periodically, changes in properties can be followed in considerable detail. At least four replicates should be examined for each exposure period to minimise the effects of atypical specimens. 

No extensive comparison with experiment to test the values in Table IV will be made. The close agreement between the purely theoretical and the experimental results in the case of helium and neon allows one to place confidence in the R values for ions with these structures and the same remark applies with less force in the case of the argon structure, where only a small empirical correction was introduced. It is interesting to note that the theoretical values 3-57 and 6-15 for the rubidium and the caesium ion agree very well with the experimental ones, 3-56 and 6-17 (Table III), which were not used at all in the evaluation of the empirical corrections for these structures. Finally, we may mention that our values agree in general with those of Fajans and WulfE.i obtained by them from the experimental R values for salt solutions by the application of only the simplest theoretical considerations. 

Rott B, Viswanathan R, Freitage D, et al. 1982. Comparison of the applicability of various tests for screening the degradability of environmental chemicals. Chemosphere 11 1-10. 

Aqueous solubility is selected to demonstrate the E-state application in QSPR studies. Huuskonen et al. modeled the aqueous solubihty of 734 diverse organic compounds with multiple linear regression (MLR) and artificial neural network (ANN) approaches [27]. The set of structural descriptors comprised 31 E-state atomic indices, and three indicator variables for pyridine, ahphatic hydrocarbons and aromatic hydrocarbons, respectively. The dataset of734 chemicals was divided into a training set ( =675), a vahdation set (n=38) and a test set (n=21). A comparison of the MLR results (training, r =0.94, s=0.58 vahdation r =0.84, s=0.67 test, r =0.80, s=0.87) and the ANN results (training, r =0.96, s=0.51 vahdation r =0.85, s=0.62 tesL r =0.84, s=0.75) indicates a smah improvement for the neural network model with five hidden neurons. These QSPR models may be used for a fast and rehable computahon of the aqueous solubihty for diverse orgarhc compounds. 

The results of such multiple paired comparison tests are usually analyzed with Friedman s rank sum test [4] or with more sophisticated methods, e.g. the one using the Bradley-Terry model [5]. A good introduction to the theory and applications of paired comparison tests is David [6]. Since Friedman s rank sum test is based on less restrictive, ordering assumptions it is a robust alternative to two-way analysis of variance which rests upon the normality assumption. For each panellist (and presentation) the three products are scored, i.e. a product gets a score 1,2 or 3, when it is preferred twice, once or not at all, respectively. The rank scores are summed for each product i. One then tests the hypothesis that this result could be obtained under the null hypothesis that there is no difference between the three products and that the ranks were assigned randomly. Friedman s test statistic for this reads... 

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