NIST Digital Archives
Not a member yet
149436 research outputs found
Sort by
Atomic force microscope cantilever flexural stiffness calibration: Toward a standard traceable method
No full textmicroscope into a useful tool for measuring mechanical properties of surfaces at the nanoscale has spurred the need for more precise and accurate methods for calibrating the spring constants of test cantilevers. Groups within international standards organizations such as the International Organization for Standardization and the Versailles Project on Advanced Materials and Standards (VAMAS) are conducting studies to determine which methods are best suited for these calibrations and to try to improve the reproducibility and accuracy of these measurements among different laboratories. This paper expands on a recent mini round robin within VAMAS Technical Working Area 29 to measure the spring constant of a single batch of triangular silicon nitride cantilevers sent to three international collaborators. Calibration techniques included reference cantilever, added mass, and two forms of thermal methods. Results are compared to measurements traceable to the International System of Units provided by an electrostatic force balance. A series of guidelines are also discussed for procedures that can improve the running of round robins in atomic force microscopy
William F. Egelhoff
No full textWilliam F. Egelhoff
Inducted: 2011
Citation:
For world-leading developments in the science of surfaces and thin films, and fundamental work in thin-film giant magnetoresistance (GMR) spin valves which greatly helped the US magnetic data recording industry.
Tenure: 1979-2010
Birth: 1949, Norfolk, Virginia
Death: 2010
Education:
Hampden-Sydney College, BS (Chemistry), 1971
University of Cambridge, PhD (Physical Chemistry), 1975
Positions held:
Research Chemist, Surface Science Division, Center for Thermodynamics and Molecular Science, NML, 1979-1993
Research Chemist, Metallurgy Division, Materials Science and Engineering Laboratory, 1994-2005
NIST Fellow, Metallurgy Division, MSEL, 2005-2010
Honors:
U.S. Department of Commerce Silver Medal (1989) and Gold Medal (2003)
J. Vac. Sci. Technology Shop Note Award (1990)
Fellow, American Physical Society (1991); Divisional Associate Editor, Physical Review Letters (1996-2002)
NIST Stratton Award (1998)
NIST Competence (IMS) Program Award (1991, 2003, and 2010)
NIST Representative to the National Storage Industry Consortium (1992-2010)
Memberships:
American Physical Society
Publications:
More than 225 publications including:
Kief, M.T. and Egelhoff, W.F., “Growth and Structure of Fe and Co Thin Films on Cu(111), Cu(100), and Cu(110) - A Comprehensive Study of Metastable Film Growth,” Physical Review B 47, 10785-10814 (1993)
Egelhoff, W.F. and Jacob, I., “Reflection High Energy Electron Diffraction (RHEED) Oscillations at 77-K,” Physical Review Letters 62, 921-924 (1989)
Egelhoff, W.F. and Steigerwald, D.A., “The Role of Adsorbed Gases in Metal on Metal Epitaxy,” Journal of Vacuum Science & Technology A-Vacuum Surfaces and films 7, 2167-2173 (1989)
Egelhoff, W.F., Chen, P.J., Powell, C.J., et al., “Oxygen as a Surfactant in the Growth of Giant Magnetoresistance Spin Valves,” Journal of Applied Physics 82, 6142-6151 (1997)
Egelhoff, W.F., “Role of Multiple Scattering in X-Ray Photoelectron Spectroscopy and Auger-Electron Diffraction in Crystals,” Physical Review Letters 59, 559-562 (1987)
Egelhoff, W.F., Gan, L., Ettedgui, H., et al., “Artifacts in Ballistic Magnetoresistance Measurements,” Journal of Applied Physics 95, 7554-7559 (2004
Frank W. J. Olver
No full textFRANK W. J. OLVER
Inducted: 2011
Citation: For prolific contributions in applied mathematics, including those to the NBS Handbook of Mathematical Functions (1964) and its successor, the NIST Digital Library of Mathematical Functions (2010).
Tenure: 1961-1986
Birth: 1924, Croydon, United Kingdom
Education:
University of London, BS (Mathematics), 1945
University of London, MS (Mathematics), 1948
University of London, DSc (Mathematics), 1961
Positions held:
Mathematician, Mathematical Analysis Division, Center for Applied Mathematics, National Engineering Laboratory, 1961-1986
Guest Researcher, Mathematical and Computational Sciences Division, Information Technology Laboratory, 1986-Present
Honors:
US Department of Commerce Silver Medal (1969)
Fellow and Chartered Member, Institute of Mathematics and Its Applications, UK
Foreign Member, Royal Society of Sciences, Uppsala, Sweden
Conference “Asymptotic and Computational Analysis”, University of Manitoba, Winnipeg, Canada (1989), with Proceedings published by Marcel Dekker in honor of Olver’s 65th birthday (1990)
Conference “Asymptotics and Applied Analysis”, San Diego State University, San Diego, CA (2000) in honor of Olver’s 75th birthday
Conference “Special Functions in the 21st Century: Theory & Applications”, Washington, DC (2011) with special recognition of Professor Frank W.J. Olver
Memberships:
Member, American Mathematical Society; Society for Industrial and Applied Mathematics; and Mathematical Association of America
Managing Editor, SIAM Journal on Mathematical Analysis (1969-74)
Editorial Board Member, SIAM Journal on Numerical Analysis (1964-69); SIAM Journal on Mathematical Analysis (1975-94); Methods and Applications of Analysis (1992-1999)
Assoc. Editor, Journal of Research of NBS, Section B: Mathematical Sciences (1966-78); Mathematics of Computation (1984-1995)
Publications:
More than 100 publications and books including:
Olver, F.W.J., Chapter “Bessel Functions of Integer Order” NBS Handbook of Mathematical Functions, AMS55, 355-433 (1964)
Olver, F.W.J., Editor-in-Chief, NIST Handbook of Mathematical Functions, and author of 5 chapters (2010)
Olver, F.W.J., Asymptotics and Special Functions, Academic Press (1974); Russian translation (1990); reprinted in AKP Classics Series by A. K. Peters (1997)
Wong, R., Editor two volumes, Selected Papers of F. W. J. Olver, World Scientific Series in 20th Century Mathematics, World Scientific, Singapore (2000
Alan F. Clark
No full textALAN F. CLARK
Inducted: 2011
Citation:
For research and leadership excellence in cryogenic properties of materials, superconductivity, and electrical and magnetic standards
Tenure: 1964-2004
Birth: 1936, Milwaukee, Wisconsin
Education:
University of Wisconsin, BS (Physics), 1958
University of Wisconsin, MS (Nuclear Engineering), 1959
University of Michigan, PhD (Nuclear Science), 1964
Positions held:
National Research Council Postdoctoral Associate, NBS (Boulder), 1964-1966
Physicist, Cryogenics Division, Institute for Basic Standards (Boulder), 1966-1977
Leader, Thermophysical Properties of Solids Group, Thermophysical Properties Division, NML (Boulder), 1978-1980
Leader, Superconductor & Magnetic Measurement Group, Electromagnetic Technology Div., NEL (Boulder), 1981-1987
Liaison Scientist, Office of Naval Research, London, UK, (1988-1989)
Leader, Fundamental Electrical Measurements Group, Electricity Division, EEEL (Gaithersburg), 1989-1998
Deputy Chief, Optoelectronics Division, EEEL (Boulder), 1998-2000
Chief, Magnetic Technology Division, EEEL (Boulder), 2001-2003
Chief, Materials Reliability Division, MSEL (Boulder), 2004
Honors:
US Department of Commerce Silver Medal (1987)
Fellow, American Physical Society (1988)
Fellow, Institute of Electrical and Electronics Engineers (1995)
Chairman and President of Board of Directors, Applied Superconductivity Conference
Memberships:
IEEE Transactions on Applied Superconductivity, Editor-in-Chief (1994–1997)
Cryogenics, Americas Editor (1982–1994), Advisory Editor (1977–1981)
Superconductivity, Advisory Editor (1987–1998)
Advances in Cryogenic Engineering—Materials, Plenum, Co-Editor, (1975–1988)
International Cryogenic Monographs, Plenum, Co-Editor (1978–2005)
Materials at Low Temperatures, American Society for Metals, Co-Editor and author (1983)
Founded and chaired: International Cryogenic Materials Conference, International Critical Currents Conference, APS Instrument and Measurement Science Topical Group, Joseph F. Keithley Award Committee, IEEE Committee on Superconductivity, and ASTM B01.08 Committee on Superconductors
Publications:
More than 150 publications and a patent including:
Clark, A.F., Zimmerman, N.M., Williams, E.R., Amar, A., et. al., “Application of Single Electron Tunneling: Precision Capacitance Ratio Measurements,” Appl. Phys. Lett. 66, 2588 (1995)
Early, E.A., Clark, A.F., and Char, K., “Half-Integral Constant Voltage Steps in High-Tc Grain Boundary Junctions,” Appl. Phys. Lett. 62, 3357 (1993)
Moreland, J., Clark, A.F., Goodrich, L.F., Ku, H.C., and Shelton, R.N., “Tunneling Spectroscopy of a La-Sr-Cu-O Break Junction: Evidence for Strong Coupling Superconductivity,” Phys. Rev. B 35, 8711 (1987)
Ekin, J.W., Fickett, F.R., and Clark, A.F., “Effect of Stress on the Critical Current of NbTi Multifilamentary Composite Wire,” Adv. Cryo. Eng. 22, 449 (1977)
Clark, A.F., Childs, G.E., and Wallace, G.H., “Electrical Resistivity of Some Engineering Alloys at Low Temperatures,” Cryogenics 10, 295 (1970)
Clark, A.F., “Low Temperature Thermal Expansion of Some Metallic Alloys,” Cryogenics 8, 282 (1968
Comparison between the NIST and the KEBS for the determination of air kerma calibration coefficients for narrow x-ray spectra and Cs-137 gamma-ray beams
No full textAir kerma calibration coefficients for a reference class ionization chamber from narrow x-ray spectra and cesium 137 gamma-ray beams were compared between the National Institute of Standards and Technology (NIST) and the Kenya Bureau of Standards (KEBS). A NIST referenceclass transfer ionization chamber was calibrated by each laboratory in terms of the quantity air kerma in four x-ray reference radiation beams of energies between 80 kV and 150 kV and in a cesium 137 gamma-ray beam. The reference radiation qualities used for this comparison are described in detail in the ISO 4037 publication.[1] The comparison began in September 2008 and was completed in March 2009. The results reveal the degree to which the participating calibration facility can demonstrate proficiency in transferring air kerma calibrations under the conditions of the said facility at the time of the measurements. The comparison of the calibration coefficients is based on the average ratios of calibration coefficients
Fracture toughness of veneering ceramics for fused to metal (PFM) and zirconia dental restorative materials
No full textVeneering ceramics designed to be used with modern zirconia framework restorations have been reported to fracture occasionally in vivo. The fracture toughness of such veneering ceramics was measured and compared to that of conventional feldspathic porcelain veneering ceramics for metal framework restorations. The fracture toughness of the leucite free veneer was measured to be 0.73 MPa m + 0.02 MPa m, which is less than that for the porcelain fused to metal (PFM) veneering ceramic: 1.10 MPa +/- 0.2 MPa. (Uncertainties are one standard deviation unless otherwise noted.) The surface crack in flexure (SCF) method was suitable for both materials, but precrack identification was difficult for the leucite containing feldspathic porcelain PFM veneer
Estimating volumes of near-spherical molded artifacts
No full textThe Food and Drug Administration (FDA) is conducting research on developing reference lung cancer lesions, called phantoms, to test computed tomography (CT) scanners and their software. FDA loaned two semi-spherical phantoms to the National Institute of Standards and Technology (NIST), called Green and Pink, and asked to have the phantoms volumes estimated. This report describes in detail both the metrology and computational methods used to estimate the phantoms volumes. Three sets of coordinate measuring machine (CMM) measured data were produced. One set of data involved reference surface data measurements of a known calibrated metal sphere. The other two sets were measurements of the two FDA phantoms at two densities, called the coarse set and the dense set. Two computational approaches were applied to the data. In the first approach spherical models were fit to the calibrated sphere data and to the phantom data. The second approach was to model the data points on the boundaries of the spheres with surface B-splines and then use the Divergence Theorem to estimate the volumes. Fitting a B-spline model to the calibrated sphere data was done as a reference check on the algorithm performance. It gave assurance that the volumes estimated for the phantoms would be meaningful. The results for the coarse and dense data sets tended to predict the volumes as expected and the results did show that the Green phantom was very near spherical. This was confirmed by both computational methods. The spherical model did not fit the Pink phantom as well and the B-spline approach provided a better estimate of the volume in that case
(Audio Part 1 of 3) Oral history interview of John (Jack) Wachtman, February 4, 2010 / with David Lide, Edwin Fuller, Sheldon Wiederhorn and Hans Oser
No full textOral history interview of Dr. John Wachtman, who had an active career in the Material Science area of the NBS, the predecessor of NIST. Dr. Wachtman first joined NBS as a bench scientist. Dr. Wachtman spent thirty-two years at NIST starting in 1951
Interim report on the examination of corrosion damage in homes constructed with imported wallboard: Examination of samples received September 28, 2009
No full textSince many household systems are fabricated out of metallic materials, changes to the household environment that accelerate corrosion rates will increase the frequency of failures in these systems. Recently, it has been reported that homes constructed with imported wallboard have increased failure rates in appliances, air conditioner heat exchanger coils, and visible corrosion on electrical wiring and other metal components. At the request of the Consumer Product Safety Commission (CPSC), the National Institute of Standards and Technology (NIST) became involved through the Interagency Agreement CPSC-1-09-0023 to perform metallurgical analyses on samples and corrosion products removed from homes constructed using imported wallboard. This document reports on the analysis of the first group of samples received by NIST from CPSC. The samples received by NIST on September 28, 2009 consisted of copper tubing for supplying natural gas and two air conditioner heat exchanger coils. The examinations performed by NIST consisted of photography, metallurgical cross-sectioning, optical microscopy, scanning electron microscopy (SEM), and x-ray diffraction (XRD). Leak tests were also performed on the air conditioner heat exchanger coils. The objective of these examinations was to determine extent and nature of the corrosive attack, the chemical composition of the corrosion product, and the potential chemical reactions or environmental species responsible for accelerated corrosion. A thin black corrosion product was found on samples of the copper tubing. The XRD analysis of this layer indicated that this corrosion product was a copper sulfide phase and the diffraction peaks corresponded with those for the mineral digenite (Cu9S5). Corrosion products were also observed on other types of metals in the air conditioner coils where condensation would frequently wet the metals. The thickness of the corrosion product layer on a copper natural gas supply pipe with a wall thickness of 1.2 mm +/- 0.2 mm was between 5 micrometers and 10 micrometers. These results indicate that a chemical compound that contains reduced sulfur, such as hydrogen sulfide (H2S), is present in the environment to which these samples were exposed. The literature indicates that these species strongly influence corrosion rates of most metals and alloys even at low concentrations. None of the samples examined were failed components, and no evidence of imminent failure was found on any of the samples examined. All of the corrosion damage observed to date is consistent with a general attack form of corrosion that will progress in a uniform and relatively predictable manner. No evidence of localized attack was found, but these forms of attack typically require an incubation period before they initiate. Therefore, the number of samples examined to date is too small to draw a conclusion on the relative probability of these forms of corrosion being able to cause or not cause failure. Samples from failed systems or from laboratory tests conducted over a wide range of metallurgical and environmental conditions will be required to assess the probability of these other forms of corrosion causing failure
Variances of plane parameters fitted to range data
No full textFormulas for variances of plane parameters fitted with Nonlinear Least Squares to point clouds acquired by 3D imaging systems (e.g., LADAR) are derived. Two different error objective functions used in minimization are discussed: the orthogonal and the directional functions. Comparisons of corresponding formulas suggest the two functions can yield different results when applied to the same dataset