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NIST Authors in Bold

Displaying 526 - 550 of 1721

Forced Assembly and Mixing of Melts via Planar Polymer Micro-Mixing

June 24, 2010
Author(s)
Doyoung Moon, Kalman D. Migler
The ability to force immiscible polymers into specific, targeted structures would enable the generation of blends with tailored performance by exploiting the intimate relationship between structure and blend properties. Here we present a strategy for the

Challenges in Sustainable Polymeric Materials

May 19, 2010
Author(s)
Kathryn L. Beers, Christopher M. Stafford
While there are many societal and economic factors that contribute to a sustainable civilization, there are also real technical and scientific problems that must be solved to provide the materials necessary to make progress towards the goal of

Molecular Mass Distribution Measurement by Mass Spectrometry

May 19, 2010
Author(s)
William E. Wallace, Charles M. Guttman
This NIST Recommended Practice Guide presents a method using mass spectrometry to make a quantitative determination of the molecular mass distribution of narrow polydispersity synthetic molecular materials. The main obstacle for converting an oligomer

Reactive MALDI Mass Spectrometry of Saturated Hydrocarbons: A Theoretical Study

May 1, 2010
Author(s)
William E. Wallace, Lewandowski Hans, Meier J. Robert
Recently it has been shown that the cobaltocenium cation, prepared by the laser ablation of a CoCp(CO)2/fullerene matrix, may react with alkanes and polyethylenes in the gas phase via a dehydrogenation reaction to produce [Co(Cp)2(alkadiene)]+ ions without

An Octacalcium Phosphate Forming Cement

April 16, 2010
Author(s)
Milenko Markovic, Laurence C. Chow
The osteoconductive and possibly osteoinductive characteristics of OCP increased the interest in preparation of bone graft materials that contain OCP in its composition. Calcium phosphate cements (CPCs) were prepared using a mixture of α tricalcium

Near-Field Antenna as a Scanning Microwave Probe for Characterization of Materials and Devices

April 12, 2010
Author(s)
Atif A. Imtiaz, Thomas M. Wallis, SangHyun S. Lim, Jonathan Chisum, Zoya Popovic, Pavel Kabos
The Scanning Microwave Probe (SMP) is emerging as an important broadband metrology tool for characterizing the materials and devices in the micron and sub-micron length scales in the frequency range of 10 MHz to 110 GHz. In this document we establish three

Properties of Injectable Apatite-Forming Premixed Cements

April 10, 2010
Author(s)
Yasushi Shimada, Laurence Chow, Shozo Takagi, Junji Tagami
A previously reported, premixed calcium phosphate cements (CPC) forms hydroxyapatite (HA) as the only product, but had a setting time greater than 60 min. This study investigated properties of fast-hardening HA-forming premixed CPCs. All cements consisted

Adhesion research at the National Institute of Standards and Technology (NIST)

April 1, 2010
Author(s)
Christopher M. Stafford, Adam J. Nolte, Gale A. Holmes, Sheng Lin-Gibson, John A. Howarter
NIST s involvement in adhesion research has been wide ranging and is ultimately in response to interactions between individual project leaders and our industrial partners. In this way, NIST s participation in the Adhesion Society has been instrumental in

Novel Dimethacrylates with Quaternary Ammonium Functionalities for Reduced Bacteria Adhesion

April 1, 2010
Author(s)
Nancy J. Lin, Joseph M. Antonucci, Diana N. Zeiger, Kathy Tang, Bruce O. Fowler, Sheng Lin-Gibson
Biofilm growth and secondary caries have resulted in the failure of many dental composite restorations. One approach to address this issue is the modification of dental materials to reduce bacterial adhesion and biofilm growth. Quaternary ammonium salts

Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes

March 26, 2010
Author(s)
Erik K. Hobbie, Daneesh O. Simien, Jeffrey A. Fagan, JiYeon Huh, Jun Y. Chung, Steven D. Hudson, Jan Obrzut, Jack F. Douglas, Christopher M. Stafford
Ultrathin layers of single-wall carbon nanotubes (SWCNTs) show considerable promise for applications ranging from fuel-cell membranes and biochemical sensors to bioactive films and transparent electrodes. The high conductivity and extreme anisotropy of

Harnessing Wrinkle Delamination Mechanics to Measure and Pattern Polymer Coatings

March 21, 2010
Author(s)
Adam J. Nolte, Jun Y. Chung, Christopher Stafford
Compressive stresses in stiff polymer coatings can give rise to surface instabilities in which the coating adopts a sinusoidally wrinkled morphology with a dominant wavelength, d, as displayed in Figure 1a. Such instabilities are generally observed for

Influence of molecular mass on the modulus of thin polystyrene films

March 21, 2010
Author(s)
Jessica M. Torres, Christopher Stafford, Bryan D. Vogt
In this work, we examine the influence of relative molecular mass (Mn, or the number average molecular mass) of PS on the thickness-dependent moduli using a wrinkling based instability of a stiff film on an elastic substrate. This wrinkling based metrology

No Calcium Fluoride Found in Plaque Following a NaF Rinse

February 24, 2010
Author(s)
Gerald L. Vogel, Livia M. Tenuta, Gary E. Schumacher, Laurence C. Chow
Background: Plaque calcium fluoride or biological/bacterial calcium-fluoride deposits appear to be the source of cariostatic concentrations of fluoride in plaque fluid. Aims: (1) To quantify the amount of plaque calcium fluoride after a NaF rinse. (2) To

Electrically-stimulated gradients in water and counterion concentrations within electroactive polymer actuators

February 1, 2010
Author(s)
Jong Keun Park, Paul J. Jones, Chris Sahagun, Kirt A. Page, Daniel S. Hussey, David L. Jacobson, Sarah E. Morgan, Robert B. Moore
While ionic polymer metal composites (IPMCs) have been studied for more than 10 years, the specific actuation mechanism is still unclear. In this work, neutron imaging, applied potential (AP) and current sensing (CS) atomic force microscopy (AFM) methods

Elastic constants and dimensions of imprinted polymeric nanolines determined from Brillouin light scattering

January 18, 2010
Author(s)
Ward L. Johnson, Sudook A. Kim, Roy H. Geiss, Colm Flannery, Paul R. Heyliger, Christopher L. Soles, Wen-Li Wu, Chengqing C. Wang, Christopher M. Stafford, B D. Vogt
Elastic constants and cross-sectional dimensions of imprinted nanolines of poly(methyl methacrylate) (PMMA) on silicon are determined nondestructively from finite-element inversion analysis of dispersion curves of hypersonic acoustic modes of these

Gradient and Microfluidic Library Approaches to Polymer Interfaces

January 1, 2010
Author(s)
Michael J. Fasolka, Christopher M. Stafford, Kathryn L. Beers
We present and overview of research conducted at the National Institute of Standards and Technology aimed at developing combinatorial and high throughput measurement approaches to polymer surfaces, interfaces and thin films. Topics include, 1) the
Displaying 526 - 550 of 1721