NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
For electrostatically stabilized colloids, an increase in salt concentration typically causes a decrease in stability, until the electrical double layer is collapsed, in which case the instability remains as salt concentration is increased further. In
Stephen M. Hsu, P M. McGuiggan, J Zhang, Y L. Wang, F Yin, Y P. Yeh, Richard S. Gates
An atomic force microscope (AFM), a surface forces apparatus (SFA), and a ball-on-inclined plane (BOIP) apparatus were used to measure the mechanical properties of thin films. The frictional force (lateral resistance) of a set of four samples with
E J. Nelson, Joseph C. Woicik, Z Hasan, Z -. Shen, D Heskett, L E. Berman
In the vicinity of an x-ray Bragg reflection, the incident and reflected x-rays coherently superpose to form an x-ray standing wave, with a periodicity equal to the diffracting plane spacing. The phase relationship between the two x-rays can be tuned by
Robert A. Bubeck, Barry J. Bauer, P Dvornic, M J. Owen, S Reeves, P Parkham, L W. Hoffman
There is considerable interest in the development of nanocomposites based on dendrimers as host matrices. The intent is to take advantage of functionalized dendrimer interiors that can complex with an added constituent, resulting in nanocomposites for
Igor Levin, Lawrence H. Robins, Mark D. Vaudin, J A. Tuchman, E Lakin, M J. Sherman, J Ramer
A periodic modulation with the wavevector parallel to the [0001] direction was observed in the AlGaN layers of a thick AlGaN/GaN multilayer heterostructure grown by metalorganic chemical vapor disposition. The modulation was attributed to a nearly
The objective of this project is to develop international standard test methods for assessing the reliability of ceramic components used in diesel engines and other heavy vehicle propulsion systems. Advanced ceramics such as silicon nitride offer a unique
A non-contact temperature monitoring technique based on fluorescence spectroscopy was used to measure the temperature of a polymer resin during capillary rheometry testing. Polyethylene doped with a fluorescent dye, perylene, was used in experiments that
F Lofaj, Sheldon M. Wiederhorn, Gabrielle G. Long, P R. Jemian
The tensile creep behavior of a Lu-containing silicon nitride (SN 281) was characterized in the temperature range of 1350oC to 1550oC for test periods up to 10000h. For the same test conditions, the minimum strain rates were several orders of magnitude
The friction of three chemically distinct esters was measured in order to determine how molecular architecture influences friction. The friction coefficients of mica surfaces separated by a thin film (
hesion at the fiber matrix interface of composite specimens is often ascribed to the following factors (Sharpe and Drzal): (1) mechanical interlocking, (2) physicochemical interactions, (3) chemical bonding, and (4) mechanical deformation of the fiber
Controlled wear testing should be used to develop understanding of wear mechanisms and the influence of various parameters on materials behavior. Simulator testing should be used to test different designs after the material behavior has been assessed. Used
Winnie K. Wong-Ng, James A. Kaduk, Qingzhen Huang, Robert S. Roth
The crystal structure of the low temperature oxidized form of Sr 3.94Ca 1.31Bi 2.70O 12 has been determined using a combined Rietveld refinement technique with neutron, synchrotron, and powder x-ray diffraction data. The structure is pseudo-orthorhombic
S Sambasivan, Daniel A. Fischer, B M. DeKoven, A Kuperman
Near-Edge Soft X-ray Absorption Spectroscopy Fine Structure (NEXAFS) electron yield (surface sensitive about 50 ) and fluorescence yield (bulk sensitive) have been applied simultaneously to characterize the adsorbed state of propylene in the surface and
The work of J.R. Rice has been central to developments in solid mechanics over the last thirty years. This volume collects 21 articles on deformation and fracture in honor of J.R. Rice on the occasion of his 60th birthday. Contributors include students (P
Winnie K. Wong-Ng, Alan D. Mighell, Gabrielle G. Long, Leonid A. Bendersky, Vicky L. Karen, J D. Barnes, G L. Gilliland, T Gallagher, Terrell A. Vanderah, R G. Munro, Paul E. Stutzman, H F. McMurdie, S Block, Gasper J. Piermarini, Robert S. Roth, Antonio Santoro, Curt W. Reimann, C R. Hubbard, John W. Cahn, E Prince, D R. Lide, H Ondik, Lawrence P. Cook, T Siegrist, G DeTitta, L Finger, H Evans, E Gabe, G Enright, J T. Armstrong, M Levenson, Laurence C. Chow, Shozo Takagi, M Mathew, Jeffrey W. Lynn, H S. Peiser
NIST has a long history of crystallographic research, and has made significant contributions to the advancement of the fields of crystallography, biology, and materials science. The articles are contributed by scientists from various divisions at NIST, and
A front-tracking finite element method is used to compute the evolution of a crack-like defect that propagates by stress driven corrosion in an isotropic, linear elastic solid. Depending on material properties, loading, and temperature, we observe three
Templated grain growth is a promising processing route for the development of highly textured polycrystalline ceramics. The development of texture in ceramic materials has been an acknowledged, but poorly characterized, process. Several mechanisms have
The Centennial Celebration of the National Institute of Standards and Technology (NIST), formerly known as the Bureau of Standards (NBS), takes place in the year 2001. NIST has a long history (>50 years) of crystallographic research, and has made
Shin-ichi Nakao, K Ohwada, N Takesue, Y Fujiii, M Isobe, Y Ueda, M V. Zimmermann, J P. Hill, D Gibbs, Joseph Woicik, L Koyama, Y Murakami
Charge ordering of V 4+ and V 5+ in NaV 2O 5 has been studied by an X-ray diffraction technique using anomalous scattering near a vanadium K-aborption edge to critically enhance a contrast between the two ions. A dramatic energy dependence of the
D M. Potrepka, J. I. Budnick, A R. Moodenbaugh, Daniel A. Fischer, W A. Hines
Zero-field 63,65Cu nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) spectra were obtained at 1.3 K for powdered samples of Y 1-xCa xBa 2Cu 3O y with 0 less than or equal to} x less than or equal to} 0.20. The results for the
Brian R. Lawn, K S. Lee, Herzl Chai, Antonia Pajares, D K. Kim, S Wuttiphan, I M. Peterson, X Z. Hu
A conceptually new approach to the design of brittle coating structures on soft substrates, based on prevention of crack initiation rather than on customary crack containment, is outlined. Concentrated loads produce two competing coating fracture modes