Ablative materials comparative performances

The previous chapters of this book have discussed the many activities which laboratories undertake to help ensure the quality of the analytical results that are produced. There are many aspects of quality assurance and quality control that analysts carry out on a day-to-day basis to help them produce reliable results. Control charts are used to monitor method performance and identify when problems have arisen, and Certified Reference Materials are used to evaluate any bias in the results produced. These activities are sometimes referred to as internal quality control (IQC). In addition to all of these activities, it is extremely useful for laboratories to obtain an independent check of their performance and to be able to compare their performance with that of other laboratories carrying out similar types of analyses. This is achieved by taking part in interlaboratory studies. There are two main types of interlaboratory studies, namely proficiency testing (PT) schemes and collaborative studies (also known as collaborative trials). 

Tests are performed for a wide variety of different reasons. Many tests have as a goal to compare different materials, procedures, products, and so on. For such comparisons to be meaningful, it is important that some type of standard procedure be used to obtain the information that will be used for comparison. This is, of course, one of the most important reasons for having standards. The goal is to separate, as much as possible, the results obtained from differences due to the laboratory or operator. In principle, one should be able to compare results from one operator (say, in Europe) with those in another place (say, in the United States). 

For continuing proficiency testing schemes laboratories are able to compare their measurement result (1) with their own past performance, (2) with other laboratory s present results and, if the material has an assigned value of the measurand (3) the true value. 

In this study, performance comparisons of various catalytic materials were performed. In order to compare the performances, data from different sources were modeled, their kinetic parameters were extracted, and for comparison, all of the data used for this study were brought to a single space time and the results were compared. Some drastic changes in the catalyst performances were observed when the space time corrections were properly done. The results of this study clearly demonstrated that, it is imperative to reach a consensus about the catalyst testing procedures in order to be able to compare the performances of the catalysts tested in different laboratories. 

In addition, it is shown that, plastic pipes in the house and out (such as underground), all show good resiliency in the case of earthquakes that beats all other traditional materials available (Valencia Water Company, USA, the California private utility was able to compare the performance of three pipe materials - asbestos-cement, PVC and steel, during the catastrophic Northridge earthquake of January 1994, and found that PVC outperformed the others). Since the Kobe earthquake, which showed the structural weakness of traditional pipes, HDPE pipes are preferentially being used as gas pipes [2]. 

The calculated ionization potentials enable one to interpret the measured X-ray photoelectron spectra (XPS) of polymers. The Namur group has performed a series of investigations in this field (a review has been published elsewhere ). To be able to compare an experimental valence electron XPS with a theoretical spectrum, the intensities of the different peaks are also needed for the construction of the theoretical spectrum besides the IPs (the energy difference between the iV — 1 and N electron states). (Actually, XPSs are more important in the identification and determination of different elements in a material. For an experimental check of the calculated band structures of an organic polymer, however, the valence electron XPSs have to be used.)... 

We go next to the analysis and failure analysis block in Figure 7-11. That is, we consider the initial configuration with a particular material or materials. Then, for the prescribed loads, we perform a set of structural analyses to get the various structural response parameters like stresses, displacements, buckling loads, natural frequencies, etc. Those analyses are all deterministic processes. That is, within the limits of accuracy of the available analysis techniques, we are able to predict a specific set of responses for a particular structural configuration. We must know how a particular structural configuration behaves so we can compare the actual behavior with the desired behavior, i.e., with the design requirements. 

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