SPRT Calibration Uncertainties and Internal Quality Control at a Commercial SPRT Calibration Facility

ABSTRACT The Hart Scientific Division of the Fluke Corporation operates two accredited SPRT calibration facilities, one at the Hart Scientific factory in Utah, USA, and the other at a service facility in Norwich, UK. The US facility is accredited through NVLAP and the UK facility is accredited through UKAS. Both provide SPRT calibrations using similar equipment and procedures, and at similar levels of uncertainty. These uncertainties are among the lowest available commercially. To achieve and maintain low uncertainties, it is required that the calibration procedures be thorough and optimized for achieving these low uncertainties. However, to minimize customer downtime, it is also important that the instruments be calibrated in a timely manner and returned to the customer. Consequently, subjecting the instrument to repeated calibrations or extensive repeated measurements is not a viable approach. Additionally, these laboratories provide SPRT calibration services involving a wide variety of SPRT designs. These designs behave differently, yet predictably, when subjected to calibration measurements. To this end, a variation evaluation strategy involving both statistical process control and internal consistency measures is utilized to provide confidence in both the instrument calibration and the calibration process. This paper describes the calibration facilities, procedure, uncertainty analysis, and internal quality assurance measures employed in the calibration of SPRTs. Data will be reviewed and generalities will be presented. Finally, challenges and considerations for future improvements will be discussed

BASES OF AXIOMATIC POLYMERIZATION THEORY

The axiomatic approach as a base of the general polymerization theory has been substantiated; the following bases have been developed: bases of axiomatic chemical polymerization theory (formulation of basis principles and following consequences relatively to the mechanism, rate and structure of the forming polymers), bases of axiomatic kinetic statistical polymerization theory (formulation of basis principles for analysis of the additional molecular-mass distributions). The mechanism of the radical, cation, anion and anion-coordinated polymerization of the vinyl and diene monomers has been interprered firstly from the single positions.Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio