Investigating failures

The GMP details certain requirements for the quahty system, such as the independence and responsibihties of the quahty control unit. It requires such activities as internal audit to monitor GMP conformance, employee training, complaint investigation, failure analysis, and verification of proper manufacture and test by QC prior to release of the batch. 

Virtually every experimental chemical technique that can be applied to solutions has at one time or another been used for the investigation of isopolyanions. The often conflicting results that pervade the literature are caused by the investigators failure (a) to appreciate the complexity of the equilibria and kinetics involved and (b) realistically to assess the experimental limitations of the technique used. Clearly, there is no one experimental method that can reveal the complete story, and the literature must therefore be read extremely critically. 

For investigating failures Having established what to look for, the need more than anything is for a test which discriminates well. There is often little need for absolute accuracy or in some cases even relevance to service. 

This classification can be loosely linked to the purposes of testing. For quality control, fundamental properties are not needed, apparent properties will usually be acceptable, although functional properties would certainly be desirable. For predicting service performance, the most suitable properties would be functional ones. For design data, fundamental properties are really needed, although considerable help can often be got from functional properties. For investigating failures, the most useful test will depend on the individual circumstances but it is unlikely that fundamental methods would be necessary. 

No good evidence that monitoring the plasma concentration improves therapeutic management. Measurement may be used in test for bioavailability when investigating failure to respond. 

Lack of process and computer validation. Out-of-specification results inadequately investigated. Failure to investigate injury complaints. Cross-contamination due to improper equipment cleaning, particularly with APIs. 

The reliability parameters, such as the mean time to failure, have to be determined in experiments under well defined conditions. Failure rates of microsystems for automotive applications are typically in the range of a few ppm (parts per million). This may sound negligible, but due to the large number of sensors sold every year and their increasing numbers in each car, even this failure rate must be decreased further. However, the engineer who tries to investigate failure mechanisms is confronted with the problem of lack of failures in the sense that he finds too few defective samples for a thorough failure analysis. Thus, due to the lack of a statistical basis, the quality of lifetime predictions under normal in-use conditions would be poor. 

It is the responsibility of an independent unit, usually the quality assurance group, which is independent of production, to participate in issuing procedures, authorizing changes to processes, specifications, procedures and test methods, and in investigating failure and complaints. 

The unit strain rate curves are not fully suitable for describing the behavior of sealants, for they give little information on failure behavior because the failure points for given conditions fall at various points on them. To investigate failure properties as a function of the four basic variables a three-dimensional system has to be used an example is shown in Figure 6 for two-part polysulfide sealant. Each line represents a tensile curve, calculated from the original curves, and the failure points form the upper curved edge of the three-dimensional representation. 

The Failure Mode and Effect Analysis (FMEA) is a structured technique which investigates failure modes and their effects. The aim is to identify potential weaknesses and improve reliability, availability or safety. A system or process is hierarchically decomposed into its basic elements and then the failure modes of the elements are examined for causes and effects [3]. FMEA was developed in the 1950s... 

Procedures, acceptance criteria, and procedures for investigating failures are established. 

Hearings were then held in front of the Senate and House of Congress Armed Services Committees, after which Congress produced a report that discredited the Navy s investigation and conclusions USS Iowa Tragedy An Investigative Failure, dated March 5,1990. 

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