Interpretive evaluation

This section discusses how the interpretation, evaluation, and correlation of test results from bench-scale equipment can be integrated into an approach to inherent process safety involving reactive systems. 

After the completion of the report for our administrative audiences, we developed a range of continuing projects to carry on the cycle of interpretation, evaluation, and reflective programmatic change. The most immediate projects had to do with sharing our results and revising teacher preparation in several ways. 

Aflatest. This immunoaffinity column also met the lower detection requirement for the USFDA at a permissible limit of 20 ppb for aflatoxin. Qualitative results can be obtained using a florisil tip, however, the florisil tip was found difficult to interpret. Evaluation showed the quantitative analysis to be as accurate as other HPLC procedures, but much more rapid. Using the Aflatest for sample extract purification, and HPLC with post column derivatization using iodine, a limit of quantitation of 2.3 ppb for B and G is easily achieved. Sensitivity to B2 and G- is lower due to less specificity of the Aflatest antibodies to tnese toxins. 

Furthermore, molecular analysis is absolutely necessary for the petroleum industry in order to interpret the chemical processes being used and to evaluate the efficiency of treatments whether they be thermal or catalytic. This chapter will therefore present physical analytical methods used in the molecular characterization of petroleum. 

Within the framework of the ANDES (Automatic Non-Destructive Evaluation System) at TNO Institute of Applied Physics two prototype applications have been developed for automated NDT data interpretation - both using the CBR methodology. 

In service inspections of French nuclear Pressure Water Reactor (PWR) vessels are carried out automatically in complete immersion from the inside by means of ultrasonic focused probes working in the pulse echo mode. Concern has been expressed about the capabilities of performing non destructive evaluation of the Outer Surface Defects (OSD), i.e. defects located in the vicinity of the outer surface of the inspected components. OSD are insonified by both a "direct" field that passes through the inner surface (water/steel) of the component containing the defect and a "secondary" field reflected from the outer surface. Consequently, the Bscan images, containing the signatures of such defects, are complicated and their interpretation is a difficult task. 

Radiographic inspection is performed to reach a decision about the acceptability of the component or product being tested. Before any evaluation can be made, the interpreter must be certain that the images are satisfactory. In addition, the interpreter must have a solid understanding of the following in order to be successful with the interpretation of the radiographic film for welding quality. 

The first of them to determine the LMA quantitatively and the second - the LF qualitatively Of course, limit of sensitivity of the LF channel depends on the rope type and on its state very close because the LF are detected by signal pulses exceeding over a noise level. The level is less for new ropes (especially for the locked coil ropes) than for multi-strand ropes used (especially for the ropes corroded). Even if a skilled and experienced operator interprets a record, this cannot exclude possible errors completely because of the evaluation subjectivity. Moreover it takes a lot of time for the interpretation. Some of flaw detector producers understand the problem and are intended to develop new instruments using data processing by a computer [6]. 

The different techniques of NDT were applied to evaluate the method allowing to give an optimal spectrum so that the interpretation can be done easily. In addition, and for the purpose of the defects quantification, we have done an optimization on the magnetic powders, colored and fluorescent, by applying magnetic powders of variable dimensions. This will enable us to estimate defects with a high precision. 

In the framework of the new approach third parties have a particular responsibility. Their task has become more difficult especially in cases where products are manufactured directly to the essential requirements. In that case competent interpretation and judgement needs to be applied in order to evaluate whether the required safety level is achieved or not. Not only safeguard clauses and their economic consequences should be avoided but also possible distortion of the market. An exchange of experience between bodies which are notified for a given directive is therefore normally organised with a view to ensuring its coherent application and to avoid such negative consequences. 

The amount of printouts (i.e. EC signals) to evaluate was drastically reduced by 50%. The rejected printouts were nevertheless examined, but no erroneous interpretation occurred. 

A more elaborate theoretical approach develops the concept of surface molecular orbitals and proceeds to evaluate various overlap integrals [119]. Calculations for hydrogen on Pt( 111) planes were consistent with flash desorption and LEED data. In general, the greatly increased availability of LEED structures for chemisorbed films has allowed correspondingly detailed theoretical interpretations, as, for example, of the commonly observed (C2 x 2) structure [120] (note also Ref. 121). 

In contrast to IR and NMR spectroscopy, the principle of mass spectrometry (MS) is based on decomposition and reactions of organic molecules on theii way from the ion source to the detector. Consequently, structure-MS correlation is basically a matter of relating reactions to the signals in a mass spectrum. The chemical structure information contained in mass spectra is difficult to extract because of the complicated relationships between MS data and chemical structures. The aim of spectra evaluation can be either the identification of a compound or the interpretation of spectral data in order to elucidate the chemical structure [78-80],... 

Other methods consist of algorithms based on multivariate classification techniques or neural networks they are constructed for automatic recognition of structural properties from spectral data, or for simulation of spectra from structural properties [83]. Multivariate data analysis for spectrum interpretation is based on the characterization of spectra by a set of spectral features. A spectrum can be considered as a point in a multidimensional space with the coordinates defined by spectral features. Exploratory data analysis and cluster analysis are used to investigate the multidimensional space and to evaluate rules to distinguish structure classes. 

To obtain the monolayer capacity from the isotherm, it is necessary to interpret the (Type II) isotherm in quantitative terms. A number of theories have been advanced for this purpose from time to time, none with complete success. The best known of them, and perhaps the most useful in relation to surface area determination, is that of Brunauer, Emmett and Teller. Though based on a model which is admittedly over-simplified and open to criticism on a number of grounds, the theory leads to an expression—the BET equation —which, when applied with discrimination, has proved remarkably successful in evaluating the specific surface from a Type II isotherm. 

A manual entitled Reporting Physisorption Data for Gas/Solid Systems with Special Reference to the Determination of Surface Area and Porosity has been prepared as a provisional publication by Commission 1.6 of the International Union of Pure and Applied Chemistry (lUPAC). The purpose of the manual is to draw attention to problems involved in reporting physisorption data and to provide guidance on the evaluation and interpretation of isotherm data. The general conclusions and recommendations are very similar to those contained in Chapter 6. 

Although sealant manufacturer s Hterature commonly reports modulus values, these values must be interpreted carefully. Specimen sizes, test rate, cure conditions, and the time a sealant has been allowed to cure when tested can all have a significant effect on modulus. Therefore, for a tme comparison, sealants should be evaluated by a standard test that examines all sealants by the same procedure. In general, the longer a sealant has been allowed to cure, the more reaUstic the modulus data. 

A scientific basis for the evaluation and interpretation of data is contained in the accompanying table descriptions. These tables characterize the way in which sample values will vary by chance alone in the context of individual obsei vations, averages, and variances. 

Accounting is also the language of business, and the different departments of management use it to communicate within a broad context of financial and cost terms. Engineers involved in feasibihty studies and detailed process evaluations are dependent for financi information on the company accountants, especially for information on the way in which the company intends to allocate its overhead costs. It is vital that engineers correctlv interpret such information and that they can, if necessaiy, make tlie accountants understand the effect of the chosen method of allocation. 

---