CATEGORIES:

# Look at the picture below and complete the text with appropriate words.

Anytime a _________ is made there are a number of factors that affect how ___________ the results are. Whether you’re using a gage pin, a pressure mic, or an ultra-high accuracy CMM inspection tool, there is always some amount of measurement ___________. To simplify, measurement uncertainty is the difference between the _______ _______ and the___________ _________.

So, if all measurements have uncertainty it is imperative that we have a grasp on how much __________ there is, otherwise we will not be able to make any confident decisions based on our ____________.

Open the brackets using the verb in Passive Voice.

Find in the text Participle and comment on the function of this grammatical form in each case.

How uncertainty is applied to a measurement when making a statement of compliance (ILAC G8)

• If the specification limits (not to breach) by the measurement result, extended by half of the expanded uncertainty interval at a level of confidence of 95%, then compliance with the specification can (to state).
• Where an upper specification limit (to exceed) by the measurement result even when it (to extend) downwards by half of the expanded uncertainty interval, then noncompliance with the specification can (to start).
• If a lower specification limit is breached even when the measurement result (to extend) upwards by half of the expanded uncertainty interval, then non-compliance with the specification can (to state).
• If the measured single value without the possibility of measuring more samples from the same unit of product falls sufficiently close to a specification limit, such that half of the expanded uncertainty interval overlaps the limit, it is not possible to confirm compliance or non-compliance at the stated level of confidence. The measurement result and expanded uncertainty should (to report) together with a statement indicating that neither compliance nor non-compliance (to demonstrate).

Do written translation of the last passage in ex.9.

11. Why does the uncertainty of a measurement depend on the precision of the measuring devise? Discuss in groups.

TEXT B

What is best practice?

Sector-specific guidance is still needed in several fields in order to enable laboratories to evaluate uncertainty consistently. Laboratories are being encouraged to evaluate uncertainty, even when reporting is not required; they will then be able to assess the quality of their own results and will be aware whether the result is close to any specified limit. The process of evaluation highlights those aspects of a test or calibration that produce the greatest uncertainty components, thus indicating where improvements could be beneficial. Conversely, it can be seen whether larger uncertainty contributions could be accepted from some sources without significantly increasing the overall interval. This could give the opportunity to use cheaper, less sensitive equipment or provide justification for extending calibration intervals.

Uncertainty evaluation is best done by personnel who are thoroughly familiar with the test or calibration and understand the limitations of the measuring equipment and the influences of external factors, eg environment. Records should be kept showing the assumptions that were made, eg concerning the distribution functions referred to above, and the sources of information for the estimation of component uncertainty values, eg calibration certificates, previous data, experience of the behaviour of relevant materials.

Date: 2016-04-22; view: 1676

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