NIST completes two CIPM key comparisons. (News Briefs).Two pressure key comparisons, piloted by NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. , under the auspices of the CCM/CIPM, were recently completed. Comparison CCM CCM Contemporary Christian Music CCM Critical Care Medicine CCM County College of Morris (New Jersey) CCM Chama Cha Mapinduzi (political party, Tanzania) CCM CORBA Component Model .P-K4 spanned 1 Pa to 1000 Pa (absolute), and involved seven national metrology institutes (NMIs) using two different principal techniques (liquid-column manometers vs static expansion systems) to realize pressure. Comparison CCM.P-K5 spanned 1 Pa to 1000 Pa (differential), and involved four NMIs using two principal techniques (liquid-column manometers vs double pressure balances) to realize pressure. These comparisons encompass low to medium vacuum measurements, and are important for accurate metering of low-speed air flows. Besides concluding that the participating NMIs were generally equivalent and that there was no significant relative bias between the principal techniques, these comparisons were notable for several other reasons. Of the six prevailing pressure comparisons in the CCM, none have been completed on-schedule other than these NIST-piloted comparisons. This was achieved by simultaneously circulating two nominally-identical transfer standard packages, one each for EUROMET and APMP APMP Association of Proposal Management Professionals APMP Asia Pacific Metrology Programme APMP Associação Paulista do Ministério Público APMP Alkaline Peroxide Mechanical Pulp APMP Acid Precipitation Mitigation Program APMP Associate Project Management Professional participants, that could be used for both absolute and differential pressure measurements. Transfer standards in this pressure range have historically proven problematic and prone to large shifts. However, the NIST-developed transfer standard packages, based on a combination of high-stability MEMS (MicroElectroMechanical Systems) Tiny mechanical devices that are built onto semiconductor chips and are measured in micrometers. In the research labs since the 1980s, MEMS devices began to materialize as commercial products in the mid-1990s. pressure sensors with high-sensitivity capacitance capacitance, in electricity, capability of a body, system, circuit, or device for storing electric charge. Capacitance is expressed as the ratio of stored charge in coulombs to the impressed potential difference in volts. diaphragm diaphragm (dī`əfrăm'), term used to describe any of several large muscles, found in humans and other mammals, which separate two adjacent regions of the body. The most commonly known muscle of this class is the thoraco-abdominal diaphragm. gauges, were robust and reliable, thereby enabling the success of these comparisons. This successful effort has earned NIST recognition for its ability to engineer a first-ever comparison of this magnitude and quality over this challenging pressure range. CONTACT: Archie Miiller, (301) 975-5932; archie. miiller@nist.gov. |
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