Critical instruments identification

Dow s Critical Instruments Program describes identification of critical instruments, and provides guidelines for their design, installation, testing, maintenance, and documentation. 

Identification of critical instruments is the responsibility of the owner of the process and usually is a part of process research and design. In addition to recognizing critical instruments, the operation must be reviewed to make certain that instrumentation is adequate to prevent a serious incident. 

Consider again a batch polymerization process where the process is characterized by the sequential execution of a number of steps that take place in the two reactors. These are steps such as initial reactor charge, titration, reaction initiation, polymerization, and transfer. Because much of the critical product quality information is available only at the end of a batch cycle, the data interpretation system has been designed for diagnosis at the end of a cycle. At the end of a particular run, the data are analyzed and the identification of any problems is translated into corrective actions that are implemented for the next cycle. The interpretations of interest include root causes having to do with process problems (e.g., contamination or transfer problems), equipment malfunctions (e.g., valve problems or instrument failures), and step execution problems (e.g., titration too fast or too much catalyst added). The output dimension of the process is large with more than 300 possible root causes. Additional detail on the diagnostic system can be found in Sravana (1994). 

The consensual identification and control of the unit of payment together with an agreed approach towards profit sharing seemed to be the most time-consuming and sophisticated steps during the development of the model. Instruments such as UNIDO s Toolkit or quality assurance systems will be supportive in managing that critical and important stage. 

Identification of supporting systems Alarms, interlocks, and controls Drawings on file and referenced drawings Critical process instrumentation Reference instrumentation Equipment manual... 

CRITICAL ASSESSMENT OF THE METHOD Since MS instrumentations today are robust and sensitive, protein identification by PMF is quite good. The rapid development of protein and gene sequence databases provides an ever more consistent platform for searches. Furthermore, improvements in search algorithms and the application of sophisticated statistical methods has improved the reliability... 

The analysis of dyes and pigments for textile applications is really a very broad subject because it usually involves many different types of analyses and the use of many sophisticated instruments. It is difficult to provide a detailed coverage in a short section here. Therefore, only some basic and simple analyses are introduced. Readers who want to know more can access the books published elsewhere. - Analysis of colorants can also mean many different things. Identification of colorants on textile materials is an important aspect of forensic analysis and also very useful for textile dyers. Characterisation of colorants is critical for colour chemists to know what chemical structures the colorant has. Determination of dye classes has its practical significance in making up dyeing and printing recipes as well as in the analysis of historical textiles. 

Spectral resolution is another critical parameter that can affect observed band wavenumbers due to the overlapping of close bands, which can cause erroneous identifications of the material when comparing with standard wavenumber tables and spectral databases. The technical requirements for the construction of a miniaturized Raman spectrometer suitable for extraterrestrial planetary exploration could force a rather low spectral resolution, and so new databases adapted to low resolution spectral data would then be necessary. Nevertheless, good quality spectra are now being obtained from miniaturised Raman spectrometers such as that shown in Figure 1-18, which weighs one kilo. An example of the Raman spectrum of an extremophile obtained from this instrument in our laboratories is shown in Figure 1-19. 

We now have much better tools for assessing specificity than we had at the beginning of the pesticide age. Gas and thin layer chromatography can usually detect the presence of mixtures. They do not work so well the other way—proving the identity of a pure compound. For this you have to apply the instruments which work on the whole molecule, or appreciable or critical fractions of the molecule, such as infrared spectroscopy, nuclear magnetic resonance, or best of all, mass spectrometry. But there are always footnotes or reservations to the best of techniques. In this case, for unequivocal identification, apply the techniques only to pure samples only a small amount is needed, but it must be pure ... 

Identification of safety critical maintenance tasks are instrumental in highlighting potential maintenance system failures (Leaflet B150 in CAP 562). 

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