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Phase meter calibration at NBS
calibration; calibration uncertainty; direct digital synthesis; phase angle; phase angle standard; phase meter.
To provide a phase meter calibration service, a phase angle calibration standard has been developed at NBS. This standard is a signal generator with two sinusoidal outputs and uses direct digital synthesis to generate the signals. The phase angle...
Journal of Research of NIST and Predecessor Publications

Determination of the enthalpies of combustion and formation of substituted triazines in an adiabatic rotating bomb calorimeter
adiabatic calorimeter; aneroid calorimeter; combustion; enthalpy; fluorine compounds; formation; heat; rotating bomb calorimeter thermochemistry; triazines.
To obtain reliable thermodynamic data on substituted triazines, it is necessary to use a calorimeter that is capable of high precision with small quantities of sample and in which a homogeneous solution of the corrosive combustion products can be...
Journal of Research of NIST and Predecessor Publications

Mock occupancy before being burned to obtain information on the integrity and duration of fires in buildings
Photographs; History; Metrology; Fire prevention; Research
To obtain information on the intensity and duration of fires in buildings necessary in interpreting and applying results of furnace tests on building materials and construction, typical occupancies were burned out, with accurate determination of...
Historic Images

Genevoise Spectrometer
To lessen dependence on foreign suppliers of optical glass, the National Bureau of Standards (NBS) undertook the study of its manufacture in 1914. Good quality prisms and lenses required precise measurement of refractive index, and this...
NIST Museum Artifacts

Microarray scanner performance over a five-week period as measured with Cy5 and Cy3 serial dilution slides
cyanine dyes; instrument qualification; microarray; microarray scanner; validation
To investigate scanner performance and guide development of an instrument qualification method, slides with replicates of successive dilutions of cyanine 5 (Cy5) and cyanine 3 (Cy3) dyes (referred to as dye slides) were scanned. The successive...
Journal of Research of NIST and Predecessor Publications

The normalized reduced form and cell mathematical tools for lattice analysis - Symmetry and similarity
identification; lattice-matching strategies; lattice relationships; lattice similarity; metric lattice; normalized reduced cell and form; symmetry
To intelligently and effectively use crystallographic databases, mathematical and computer tools are required that can elucidate diverse types of intra- and interlattice relationships. Two such tools are the normalized reduced form and normalized...
Journal of Research of NIST and Predecessor Publications

NIST gas hydrate research database and web dissemination channel
clathrate hydrate; database; gas hydrate; markup language; thermophysical properties; web access
To facilitate advances in application of technologies pertaining to gas hydrates, a freely available data resource containing experimentally derived information about those materials was developed. This work was performed by the Thermodynamic...
Journal of Research of NIST and Predecessor Publications

Studies of excess heat and convection in a water calorimeter
absorbed dose; calorimeter; convection; excess heat; finite element analysis; thermistor; water calorimeter.
To explain a difference of 0.5 % between the absorbed-dose standards of the National Institute of Standards and Technology (NIST) and the National Research Council of Canada (NRCC), Seuntjens et al. suggest the fault lies with the NIST water...
Journal of Research of NIST and Predecessor Publications

Theoretical and experimental study on longitudinal impact of tapered rods
Aluminum; experiments; longitudinal impact; numerical solution; one-dimensional; plastic-wave propagation; rate-independent theory; tapered rods
To examine the adequacy of the one-dimensional, rate-independent theory of plastic-wave propagation for annealed, commerically pure aluminum, experimental results from the longitudinal impact of uniform and tapered rods are compared to a...
Journal of Research of NIST and Predecessor Publications

A Study of GPS Carrier-Phase Time Transfer Noise Based on NIST GPS Receivers
boundary discontinuity; carrier phase time transfer; GPS; long-term noise; precise point positioning (PPP); revised RINEX-shift; short-term noise; transient response
To do a better time comparison between high-precision clocks (such as a Cesium-fountain clock and Hydrogen-maser clock), we want to study and eventually lower the GPS carrier-phase time transfer noise. The GPS carrier-phase time transfer noise...
Journal of Research of NIST and Predecessor Publications

Ionization constants and reactivity of isomers of eugenol
To determine the scope of the reaction of zinc oxide with isomers of eugenol, the effect of changees in the position of the substituents in the benzene ring on the ionization constants and reactivity of these isomers has been studied. The...
Journal of Research of NIST and Predecessor Publications

A Low-Cost Fiducial Reference Phantom for Computed Tomography
centroid; Coordinate Measuring Machine; dimensional reference; medical phantom; second moment tensor; tomography
To detect the growth in lesions, it is necessary to ensure that the apparent changes in size are above the noise floor of the system. By introducing a fiducial reference, it may be possible to detect smaller changes in lesion size more reliably. We...
Journal of Research of NIST and Predecessor Publications

Accurate cross sections for microanalysis
electron beam x-ray microanalysis; electron ionization cross sections; x-ray microanalysis; microanalysis
To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction...
Journal of Research of NIST and Predecessor Publications

Spectrophotometric standards
Photometric accuracy; standards, spectrophotometric
To be useful, spectrophotometric measurements must be believable and practical. The basic standard for any believable spectrophotometric measurements is the ability to accurately compare fluxes of radiation within the framework of a well-defined...
Journal of Research of NIST and Predecessor Publications

Electromagnetic Metrology on Concrete and Corrosion
corrosion; iron oxide; nondestructive evaluation; permeability; permittivity; reinforced concrete
To augment current methods for the evaluation of reinforcing bar (rebar) corrosion within concrete, we are exploring unique features in the dielectric and magnetic spectra of pure iron oxides and corrosion samples. Any signature needs to be both...
Journal of Research of NIST and Predecessor Publications

The microcalorimeter for industrial applications
cryogen-free cooling; energy resolution; microcalorimeter energy dispersive; transition-edge sensor; x-ray microanalysis; x-ray spectrometer
To achieve the dramatic increases in x-ray spectral resolution (<20 eV at 1.5k eV) desired by market segments such as the semiconductor industry, NIST developed a transition-edge sensor (TES) microcalorimeter. To bring this exciting, yet demanding,...
Journal of Research of NIST and Predecessor Publications

Non-contact methods for measuring front cavity depths of laboratory standard microphones using a depth-measuring microscope
acoustical calibration; calibration of microphones; depth-measuring microscope; front cavity depth; laboratory standard microphone; microphone calibration; microphone front cavity depth; reciprocity calibration; standard microphones
To achieve an acceptable degree of accuracy at high frequencies in some standardized methods for primary calibration of laboratory standard (LS) microphones, the front cavity depth l(fc) of each microphone must be known. This dimension must be...
Journal of Research of NIST and Predecessor Publications

Further studies in the annealing of a borosilicate glass
Annealing; borosilicate glass; glass; time-index of refraction isotherms; transformation range; index of refraction
Time-index of refraction isotherms for a borosilicate glass in the transformation region have been established. By comparing two quenched glasses of the same index, one quenched after attaining equilibrium at a given temperature and the other...
Journal of Research of NIST and Predecessor Publications

Expansions with coefficient algorithms for time domain responses of skin effect lossy coaxial cables
Coefficient algorithms; expansions; inverse Laplace transform; reflectometry; skin effect; step response; system function; transmission
Time domain step response expansions with coefficient algorithms are developed from the system function of a doubly terminated skin effect lossy coaxial transmission line. Three models of series impedance valid for (a) high frequency, (b) high and...
Journal of Research of NIST and Predecessor Publications

On the way to experimental test of the time reversal invariance in the nuclear reactions
polarized neutrons; polarized nuclei; time reversal invariance
Time (T) violation can be related with charge-parity (CP) violation through the CPT theorem. The CP violation was discovered experimentally in the K-0-meson decays about 35 years ago. The T violating interaction related with the CP violation...
Journal of Research of NIST and Predecessor Publications

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