Reference standards governance

The physics of X-ray refraction are analogous to the well known refraction of light by optical lenses and prisms, governed by Snell s law. The special feature is the deflection at very small angles of few minutes of arc, as the refractive index of X-rays in matter is nearly one. Due to the density differences at inner surfaces most of the incident X-rays are deflected [1]. As the scattered intensity of refraction is proportional to the specific surface of a sample, a reference standard gives a quantitative measure for analytical determinations. 

It appears then that the establishment of practicable and accurate reference methods presents one of the major problems in the determination of moisture in foods. The present paper summarizes some of the important factors that govern the accuracy of moisture determinations in general, and reviews some of the recently published attempts to develop methods that might serve as useful reference standards for dehydrated foods, and especially for dehydrated vegetables and fruits. 

Since the 1993 court decision against Barr Laboratories, 5 tjjg elimination of outliers has taken on a decidedly legal aspect in the U.S. (any non-U.S. company that wishes to export pharmaceuticals or preciwsor products to the U.S. market must adhere to this decision concerning out-of-specifica-tion results, too) the relevant section states that ... An alternative means to invalidate an individual OOS result... is the (outlier test). The court placed specific restrictions on the use of this test. (1) Firms cannot frequently reject results on this basis, (2) The USP standards govern its use in specific areas, (3) The test cannot be used for chemical testing results. ... A footnote explicitly refers only to a content uniformity test, 5 but it appears that the rule must be similarly interpreted for all other forms of inherently precise physicochemical methods. For a possible interpretation, see Section 4.24. 

The fundamental factors that govern the accuracy of primary reference standards are discussed in this chaptw. Even though an improved reference standard has been advocated, most of the existing air monitoring and laboratory-exposure data have as their reference the potassium iodide procedure used by either the carb, the laapcd, or the EPA. The relationship of these three variations of the potassium iodide procedure to the ultraviolet method is as follows ... 

The inter-comparison analysis adopted consists of the sample dividing method and the reference standard sample method . The former method is to divide various environmental samples collected by monitoring laboratories or the hygiene institutes of local government into two parts. One of them is then analysed by such laboratories and the other by JCAC for comparison. The latter method uses reference standard samples which are prepared by JCAC and Japan Isotope Association Corp., by adding appropriate radioactive nuclides to the materials such as aluminum oxide powder or agar. These mock-up samples are analysed by both JCAC and the monitoring laboratories. 

To ensure the compilation of consistent, complete and scientifically defensible regulatory submissions, the qualification of reference standards must be governed by a standard operation procedure. A reference standard qualification SOP will typically assign responsibility for, and include procedures to ensure that... 

All instrumental analytical methods except coulometry (Chapter 15) require calibration standards, which have known concentrations of the analyte present in them. These calibration standards are used to establish the relationship between the analytical signal being measured by the instrument and the concentration of the analyte. Once this relationship is established, unknown samples can be measured and the analyte concentrations determined. Analytical methods should require some sort of reference standard or check standard. This is also a standard of known composition with a known concentration of the analyte. This check standard is not one of the calibration standards and should be from a different lot of material than the calibration standards. It is run as a sample to confirm that the calibration is correct and to assess the accuracy and precision of the analysis. Reference standard materials are available from government and private sources in many countries. Government sources include the National Institute of Standards and Technology (NIST) in the US, the National Research Council of Canada (NRCC), and the Laboratory of the Government Chemist in the UK. 

From the three items of information it is possible to find out if an exposure is hazardous. For some agents it is necessary to complete a computation to determine the hazard for an exposure. To determine if there is a hazard, it is necessary to compare the acmal exposure to a reference standard. Reference standards come from studies of illnesses and related exposures. In some cases scientific specialists recommend allowable exposures. In other cases, government agencies set exposure limits. Not all reference standards agree on allowable exposures and exposure limits. Over time, additional studies may lower recommended exposures. Government agencies in different countries will not agree on allowable exposures. The philosophies that influence reference standards may differ. 

The main sources of government environmental standards are OSHA and EPA. OSHA sets workplace standards. NIOSH makes recommendations on exposure Umits and compiles related helpfid information. EPA sets standards for air and water quality for the general pubUc. Other agencies, like CPSC and PDA, also set reference standards related to certain products. Por work environments, the American Conference of Governmental Industrial Hygienists... 

Pressure-relief valve Pressvue- or temperature-activated device used to prevent buildup of pressure beyond a predetermined maximum that could cause a system to rupture. The design and selection of the device are dictated by codes and standards governing the safe design of the vessel or S3 tem to which it is connected. Also referred to as a relief valve, safety valve, or safety relief valve. 

The participants from Great Britain (GB) and USA expressed that they found the CRIOP method useful. The references to government standards and rules and regulations had to be updated to match the legislation in GB and USA respectively, which was also done when CRIOP was used in these countries. 

This final part of the Handbook thus includes broad recommendations on filtration equipment employment, and finishes with reference to the standards governing filter testing and performance. 

Source C. E. Moore, National Standard Reference Data Series 34, U.S. Government Printing Office, Washington, D.C.,... 

D. R. Stull and H. Prophet, project dinectots, JMNMF Thermochemical Tables, 2nd ed.. National Standards Reference Data Series, U.S. National Bureau of Standards, No. 37, June 1971, available from U.S. Government Printing Office, Supetintendent of Documents, Washington, D.C. 

This chapter provides a summary of the governing expressions describing conventional pressure-induced filtration and a description of major equipment. Standard filtration practices refers to the most common or classical method of filtration, sometimes referred to as cake filtration. 

The reason for an Exposition is so that there is a description of the system showing how it works and how it controls the achievement of quality. This is different from the policies and procedures. The policies are a guide to action and decision and as such are prescriptive. The procedures are the methods to be used to carry out certain tasks and as such are task related. They need to be relatively simple and concise. A car maintenance manual, for example, tells you how to maintain the car but not how the car works. Some requirements, such as those on traceability and identification, cannot be implemented by specific procedures although you can have specific policies covering such topics. There is no sequence of tasks you can perform to achieve traceability and identification. These requirements tend to be implemented as elements of many procedures which when taken as a whole achieve the traceability and identification requirements. In order that you can demonstrate achievement of such requirements and educate your staff, a description of the system rather than a separate procedure would be an advantage. The Exposition can be structured around the requirements of ISO/TS 16949 and other governing standards. It is a guide or reference document and not auditable. 

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