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Displaying 651 - 675 of 840

Security Assurance Levels: A Vector Approach to Describing Security Requirements

October 20, 2010
Author(s)
James D. Gilsinn, Ragnar Schierholz
Safety systems have used the concept of safety integrity levels (SILs) for almost two decades. This allows the safety of a component or system to be represented by a single number that defines a protection factor required to ensure the health and safety of

The Roles of the Mise en Pratique for the Definition of the Kelvin

October 16, 2010
Author(s)
Dean C. Ripple, Richard Davis, Bernd Fellmuth, Joachim Fischer, Graham Machin, Terry Quinn, Peter Steur, Osamu Tamura, David R. White
The mise en pratique (“practical realization”) for the definition of the kelvin (MeP-K) was created by the Consultative Committee for Thermometry (CCT) in 2006 to give practitioners of thermometry a guide to the realization of the kelvin, in accord with

Accurate Measurements of Process Gas Flow with Laminar Flow Meters

October 15, 2010
Author(s)
Thiago Cobu, Robert F. Berg, John D. Wright, Michael R. Moldover
We calibrated three models of commercially-manufactured, laminar flow meters (LFMs) with nitrogen at four pressures (100 kPa, 200 kPa, 300 kPa, and 400 kPa) over a 10:1 flow range using NIST’s primary flow standards and a physical model. Without additional

Bilateral Comparison Confirms NIMs and NISTs Gas Flow Capabilities

October 15, 2010
Author(s)
Aaron N. Johnson, CHUNHUI LI
The bilateral comparison between NIM and NIST for gas flow was conducted from June 2008 to October 2009. Two critical flow venturis (CFVs) with nominal throat diameters of 10 mm and 20 mm, respectively, were selected as transfer standards. The CFVs were

Properties for Accurate Gas Flow Measurements

October 15, 2010
Author(s)
John D. Wright
Accurate gas properties are needed to take full advantage of the low uncertainties provided by NIST’s Gas Flow Calibration Services. If a flowmeter user and NIST use different values for these properties (molecular mass, compressibility, density, viscosity

Lights, Camera, Metrology: Introducing the Metrology Careers Outreach DVD

July 25, 2010
Author(s)
Elizabeth J. Benham
The National Conference of Standards Laboratories International (NCSLI) 164 Education Liaison and Outreach Committee has coordinated the development of a Metrology Career Multimedia DVD, titled "Find a Cool Career in Metrology." The DVD is designed for use

Polycyclic Aromatic Hydrocarbons (PAHs) in a Coal Tar Standard Reference Material - SRM 1597a Updated

July 20, 2010
Author(s)
Stephen A. Wise, Dianne L. Poster, Stefan D. Leigh, Catherine A. Rimmer, Stephanie Mossner, Patricia Schubert, Lane C. Sander, Michele M. Schantz
SRM 1597 Complex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar, originally issued in 1987, was recently reanalyzed and reissued as SRM 1597a with 34 certified and 46 reference concentrations for polycyclic aromatic hydrocarbons (PAHs) and

Standard Photoacoustic Spectrometer: Model and Validation using O2 A-Band Spectra

June 30, 2010
Author(s)
Keith A. Gillis, Daniel K. Havey, Joseph T. Hodges
We model and measure the absolute response of an intensity-modulated photoacoustic spectrometer comprising a 10 cm long resonator and having a Q-factor of approximately 30. We present a detailed theoretical analysis of the system and predict its response

INTERCOMPARISON OF W-BAND STANDARD GAIN HORN ANTENNAS

June 13, 2010
Author(s)
Katherine MacReynolds, J. Kang, N. Kang, D. Gentle, Michael H. Francis
An intercomparison of power gain for W-band (75 GHz to 110 GHz) standard horn antennas has been performed among KRISS, NPL and NIST. This paper describes the comparison and its measurement results.

Cylindrical Acoustic Resonator for the Re-determination of the Boltzmann Constant

June 1, 2010
Author(s)
J.T. Zhang, H. Lin, X.J. Feng, Keith A. Gillis, Michael R. Moldover
We describe progress towards re-determining the Boltzmann constant k B using two fixed-path, gas-filled, cylindrical, acoustic cavity resonators. The longitudinal acoustic resonance modes of a cylindrical cavity have lower quality factors Q than the radial

Feasibility of an Accurate Dynamic Standard for Water Flow

June 1, 2010
Author(s)
Iosif I. Shinder, Michael R. Moldover
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates m dot of water "dynamically," that is from the time derivative of the weight W of the collection tank: m dot,dynamic = (dW/dt)/g. When data for a

Standard Reference Materials for Analysis of Dietary Supplements

June 1, 2010
Author(s)
Katherine E. Sharpless, David L. Duewer
NIST, in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS) and the Food and Drug Administration (FDA) is producing Standard Reference Materials (SRMs) for dietary supplements. This paper describes the how these

NEXT GENERATION GUARDED HAMON TRANSFER STANDARDS FOR HIGH RESISTANCE

May 1, 2010
Author(s)
Dean G. Jarrett, Andrew J. Dupree
Guarded Hamon transfer standards have been used at NIST for decades for scaling to high resistance levels. A recent project has been undertaken to apply improved designs in guarded Hamon transfer standards to the 1 MΩ to 100 MΩ ranges with the larger goal

NIST Calibration Services for Hydrometers.

April 19, 2010
Author(s)
John D. Wright, Vern E. Bean
The National Institute of Standards and Technology (NIST) provides calibration services for hydrometers used to measure liquid density. Hydrometers with scales for density, specific gravity, proof spirit for alcohol solutions, API degrees for petroleum

Certification of Drugs of Abuse in a Human Serum Standard Reference Material: SRM 1959

March 24, 2010
Author(s)
Susan S. Tai, Jocelyn L. Prendergast, Lorna T. Sniegoski, Michael J. Welch, Karen W. Phinney, Nien F. Zhang
A new Standard Reference Material (SRM) for drugs of abuse in human serum (SRM 1959) has been developed. SRM 1959 is a frozen human serum material fortified with seven drugs of abuse, benzoylecgonine (BZE), methadone (METH), methamphetamine (MAMP)

Characterization of SiGe Films for use as a National Institute of Standards and Technology (NIST) Microanalysis Reference material (RM 8905)

February 1, 2010
Author(s)
Ryna B. Marinenko, Shirley Turner, David S. Simons, Savelas A. Rabb, Rolf L. Zeisler, Lee L. Yu, Dale E. Newbury, Rick L. Paul, Nicholas W. Ritchie, Stefan D. Leigh, Michael R. Winchester, Lee J. Richter, Douglas C. Meier, Keana C. Scott, D Klinedinst, John A. Small
Bulk SiGe wafers cut from single-crystal boules and two SiGe thick films (4 m and 5 m thick) on Si wafers were evaluated with the electron probe microanalyzer for the extent of heterogeneity and composition for use as reference materials needed by the

NIST HB 105-4, Specifications and Tolerances for Reference Standards and Field Standard Weights and Measures 4. Specifications and Tolerances for Liquefied Petroleum Gas and Anhydrous Ammonia Pressurized Volumetic Field Standards

February 1, 2010
Author(s)
Georgia L. Harris, L.F. Eason
These specifications and tolerances are recommended as minimum requirements for standards used by state and local weights and measures officials and others in the regulatory verification of meters used in quantity determination of pressurized liquid
Displaying 651 - 675 of 840
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