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The effect of non-equispaced sampling instants, sub-period record epochs, and timebase gain on the information content of discretized replicas of periodic signals
No full textThe effect of non-equispaced sampling instants and timebase gain on the information content of the discretized replica of a periodic signal is examined. The effect of the duration of record epochs that are not equal to an integer number of signal periods on the information content of the discretized replica is also explored. A general model describing sampled and windowed data is provided and compared to related models developed by other researchers
Oral history interview of Russell Young, Wednesday, June 13, 2012 / with David Lide, Bill Gadzuk, Joseph Stroscio, John Villarrubia, Fred Scire, Cedric Powell, Ted Vorburger
No full textOral history interview of Dr. Russell Young at the National Institute of Standards and Technology in Gaithersburg, Maryland on Wednesday, June 13, 2012. Dr. Young was part of the Electron Physics Group at the NBS Atomic Physics Division in the mid-'60s where he started work in the field of mission microscope, which led to the invention of the topographiner, an instrument which led to the development of the scanning tunneling microscope. He retired in 1981
Fractional diffusion, low exponent Levy stable laws, and 'slow motion' denoising of helium ion microscope nanoscale imagery
No full textHelium ion microscopes (HIM) are capable of acquiring images with better than 1 nm resolution, and HIM images are articularly rich in morphological surface details. However, such images are generally quite noisy. A major challenge is to denoise these images while preserving delicate surface information. This paper presents a powerful slow motion denoising technique, based on solving linear fractional diffusion equations forward in time. The method is easily implemented computationally, using fast Fourier transform (FFT) algorithms. When applied to actual HIM images, the method is found to reproduce the essential surface morphology of the sample with high fidelity. In contrast, such highly sophisticated methodologies as Curvelet Transform denoising, and Total Variation denoising using split Bregman iterations, are found to eliminate vital fine scale information, along with the noise. Image Lipschitz exponents are a useful image metrology tool for quantifying the fine structure content in an image. In this paper, this tool is applied to rank order the above three distinct denoising approaches, in terms of their texture preserving properties. In several denoising experiments on actual HIM images, it was found that fractional diffusion smoothing performed noticeably better than split Bregman TV , which in turn, performed slightly better than Curvelet denoising
A Model for Geometry-Dependent Errors in Length Artifacts
No full textWe present a detailed model of dimensional changes in long length artifacts, such as step gauges and ball bars, due to bending under gravity. The comprehensive model is based on evaluation of the gauge points relative to the neutral bending surface. It yields the errors observed when the gauge points are located off the neutral bending surface of a bar or rod but also reveals the significant error associated with out-of-straightness of a bar or rod even if the gauge points are located in the neutral bending surface. For example, one experimental result shows a length change of greater than 1.5 �m on a 1 m ball bar with an out-of-straightness of 0.4 mm. This and other results are in agreement with the model presented in this paper
William J. Boettinger
No full textWilliam J. Boettinger
Inducted: 2012
Citation: For scientific leadership in the application of rigorous principles of thermodynamics and kinetics to the design and control of critical industrial materials and processes.?
Tenure: 1972-2011
Birth: 22 July 1946, Baltimore Maryland
Education:
The Johns Hopkins University, BES (Mechanics), 1968
The Johns Hopkins University, PhD (Metallurgy), 1972
Positions held:
NRC Postdoctoral, 1972 - 1974, Metallurgy Division, Institute for Materials Research
Metallurgist, 1974 - 2001, Metallurgy Division, Institute for Materials Research, Institute for Materials Science and Engineering, Materials Science and Engineering Laboratory
NIST Fellow, 2001 - 2011, Metallurgy Division, Materials Science and Engineering Laboratory
Honors:
US Department of Commerce Silver Medals (1983 and 1994) and Gold Medals (1999 and 2003)
American Society for Materials (ASM) Materials Science Division Award (1989)
George Kimball Burgess Award of Washington Chapter American Society of Materials (1996)
TMS Champion Mathewson Best Paper Award (with J.A. Warren) (1999)
TMS Bruce Chalmers Solidification Award (2001)
FLC Excellence in Technology Transfer Award (2002)
ISI Web of Science, Highly Cited (2004-present)
National Academy of Engineering (2006)
Presidential Rank Award (2007)
Memberships:
American Society of Materials (ASM)
The Metals, Materials and Minerals Society (TMS)
Fellow, ASM (1995)
Fellow, TMS (2006)
Publications:
More than 170 publications including:
Boettinger, W.J., " The Structure of Directional Solidified Two-Phase Sn-Cd Peritectic Alloys," Met. Trans. 5, 2023-2031 (1974)
Boettinger, W.J., Burdette, H.E., Kuriyama, H., and Green, R.E. Jr., "Asymmetric Crystal Topographic Camera," Rev. Sci. Inst. 47, 906-911 (1976)
Boettinger, W.J., Shechtman, D., Schaefer, R.J., and Biancaniello, F.S., "The Effect of Solidification Velocity on the Microstructure of Ag-Cu Alloys," Met.Trans.15A, 5-66 (1984)
Bendersky, L.A., Boettinger, W.J., Burton, B.P., Biancaniello F.S., and Shoemaker, C.B., "The Formation of Ordered Omega-Related Phases in Alloys of Composition Ti4Al3Nb," Acta Met. 38, 931-943 (1990)
Warren J. and Boettinger, W.J., "Prediction of Dendritic Growth and Microsegregation Patterns in a Binary Alloy Using the Phase-Field Method", Acta Met. et Mater., 43, 689 (1995)
Boettinger, W.J., Johnson, C.E., Bendersky, L.A., Moon, K.W., Williams, M.E., and Stafford, G.R., "Whisker & Hillock Formation on Sn, Sn-Cu and Sn-Pb Electrodeposits, " Acta Materialia, 53, 5033-5050 (2005
Measurement of Scattering Cross Section with a Spectrophotometer with an Integrating Sphere Detector
No full textA commercial spectrometer with an integrating sphere (IS) detector was used to measure the scattering cross section of microspheres. Analysis of the measurement process showed that two measurements of the extinction, one with the cuvette placed in the normal spectrometer position, and the second with the cuvette placed inside the IS, provided enough information to separate the contributions from scattering and molecular absorption. Measurements were carried out with microspheres with different diameters. The data was fitted with a model consisting of the difference of two terms. The first term was the Lorenz-Mie (L-M) cross section which modeled the total extinction due to scattering. The second term was the integral of the L-M differential cross section over the detector acceptance angle. The second term estimated the amount of forward scattered light that entered into the detector. A wavelength dependent index of refraction was used in the model. The agreement between the model and the data was good between 300 nm and 800 nm. The fits provided values for the microsphere diameter, the concentration, and the wavelength dependent index of refraction. For wavelengths less than 300 nm, the scattering cross section had significant spectral structure which was inversely related to the molecular absorption. This work addresses the measurement and interpretation of the scattering cross section for wavelengths between 300 nm and 800 nm
The interaction of radio-frequency fields with dielectric materials at macroscopic to mesoscopic scales
No full textThe goal of this paper is to overview radio-frequency (RF) electromagnetic interactions with solid and liquid materials from the macroscale to the nanoscale. The overview is geared toward the general researcher. Because this area of research is vast, this paper concentrates on currently active research areas in the megahertz (MHz) through gigahertz (GHz) frequencies, and concentrates on dielectric response. The paper studies interaction mechanisms both from phenomenological and fundamental viewpoints. Relaxation, resonance, interface phenomena, plasmons, the concepts of permittivity and permeability, and relaxation times are summarized. Topics of current research interest, such as negative-index behavior, noise, plasmonic behavior, RF heating, nanoscale materials, wave cloaking, polaritonic surface waves, biomaterials, and other topics are overviewed. Relaxation, resonance, and related relaxation times are overviewed. The wavelength and material length scales required to define permittivity in materials is discussed
Oral history interview of James Schooley, Tuesday, March 13, 2012 / with Billy Mangum, Jack Colwell, Jack Rush, Bill Gadzuk, David Lide
No full textList of names mentioned in oral history interview of James Schooley, who came to NBS in 1960 as a post-doctoral for Ernie Ambler to work on the parity apparatus which had been used to demonstrate the non-conservation of parity in the weak nuclear interactions
Brian R. Lawn
No full textBRIAN RONALD LAWN
Inducted: 2012
Citation:
For seminal work and outstanding leadership in the development of indentation and fracture mechanics methods to measure the mechanical properties of materials resulting in profound advances in several scientific disciplines.
Tenure: 1982-2009
Birth: 1938, Perth, Australia
Education:
University of Western Australia, BSc (Physics), 1959
University of Western Australia, PhD (Physics), 1963
Positions held:
Guest Scientist, Fracture and Deformation Division, National Measurement Laboratory (NML), 1975, 1979
Physicist, Ceramics Division, Center for Materials Science, NML, 1982-1987
NIST Fellow, Materials Science and Engineering Laboratory, 1987-2009
Research Associate, Material Measurement Laboratory, 2010-present
Honors:
Robert B. Sosman Award, American Ceramic Society (1982)
Edward Uhler Condon Award, NBS (1984)
Fellow, American Ceramic Society (1986)
Member, U.S. National Academy of Engineering (2001)
Honorary Doctorate of Engineering, University of Western Australia (2008)
Fellow, Australian Academy of Science (2012)
Memberships:
American Ceramic Society
National Academy of Engineering
Australian Academy of Science
Publications:
More than 300 publications, including:
Lawn, B.R., Fracture of Brittle Solids-Second Edition, Cambridge University Press (1993). (This text has remained in print since the first edition was published in 1975)
Frank, F.C., and Lawn, B.R., "On the Theory of Hertzian Fracture," Proc. Roy. Soc. Lond., A299 7 29-306 (1967)
Anstis, G.R., Chantikul, P., Marshall, D.B., and Lawn, B.R., "A Critical Evaluation of Indentation Techniques for Measuring Fracture Toughness: I. Direct Crack Measurements," J. Am. Ceram. Soc., 64 533-38 (1981). (Most cited paper ever published in J. Am. Ceram. Soc., with over 2200 citations)
Lawn, B.R., "Physics of Fracture," J. Am. Ceram. Soc., 66 83-91 (1983)
Lawn, B.R., Padture, N.P., Cai, H., and Guiberteau, F., "Making Ceramics ‘Ductile’," Science, 263 1114-16 (1994)
Lee, J.J-W., Constantino, P.J., Lucas, P.W., and Lawn, B.R. "Fracture in Teeth-A Diagnostic for Inferring Bite Force and Tooth Function," Biological Rev., 86 959-74 (2011
NIST ionization chamber "A" sample-height corrections
No full textFor over 30 years scientists in the NIST radioactivity group have been using their pressurized ionization chamber �A� (PIC �A�) to make measurements of radioactivity and radioactive half-lives. We now have evidence that some of those reported measurements were incorrect due to slippage of the source positioning ring over time. The temporal change in the holder caused an error in the source-height within the chamber, which was thought to be invariant. This unaccounted-for height change caused a change in the detector response and thus a relative error in measured activity on the order of 10-5 to 10-3 per year, depending on the radionuclide. The drifting detector response affected calibration factors and half-life determinations. After discovering the problem, we carried out historic research and new sensitivity tests. As a result, we have created a quantitative model of the effect and have used that model to estimate corrections to some of the past measurement results from PIC �A�. In this paper we report the details and results of that model. Meanwhile, we have fixed the positioning ring and are recalibrating the detector using primary measurement methods and enhanced quality control measures