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Displaying 551 - 575 of 1733

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

Heat release and structural collapse of flexible polyurethane foam

January 1, 2010
Author(s)
Roland H. Kraemer, Mauro Zammarano, Gregory T. Linteris, Ulf W. Gedde, Jeffrey W. Gilman
Flexible polyurethane foam used in upholstered furniture remains one of the major fire hazards to date. The heat release rate of burning items made of foam depends strongly on the foam's physical behavior, notably its collapse to a burning liquid that can

IMMOBILIZED ENZYME CATALYZED POLYMERIZATION REACTIONS IN MICROREACTORS

January 1, 2010
Author(s)
Santanu S. Kundu, Atul Bhangale, William E. Wallace, Kathleen M. Flynn, Richard Gross, Kathryn L. Beers
Application of microreactor technologies enable improved safety, selectivity and yield in a range of chemical reactions in addition to new measurement methods that are often faster, cheaper and more accurate than traditional methods. In this study we have

IMPACT OF IMMOBILIZATION SUPPORTS FOR POLYESTERS SYNTHESIS ACTIVITY OF CANDIDA ANTARTICA LIPASE B

January 1, 2010
Author(s)
Atul Bhangale, Santanu S. Kundu, Wenchun Xie, William E. Wallace, Kathleen M. Flynn, Kathryn L. Beers, Richard Gross
Epoxy functionalized supports are known to be suitable for industrial-scale immobilization of enzymes for biocatalysis. However, chemistry across these epoxy groups is known to affect the catalytic performance of the enzymes.In order to achieve a balance

Nanofiber Supported Phospholipid Bilayers

December 27, 2009
Author(s)
Feng Yi, Jian Xu, David A. LaVan
This work reports on the creation and characterization of nanofiber supported bilayers to mimic the hydrodynamic, chemical and mechanical environment provided by the actin network which supports natural lipid bilayers within a cell. Lipid bilayers were

Gradient Nanofiber Scaffold Libraries for Rapid Screening of Cell-Material Interactions

December 1, 2009
Author(s)
Carl G. Simon Jr., Murugan Ramalingam, Marian F. Young, Vinoy Thomas
Scaffolds play a key role in tissue engineering wherein they provide structural support for cells to adhere, grow and guide them to synthesize tissue. Scaffolds made of multiple biomaterials are typically required to mimic the three-dimensional (3D)

NIST Reference Material Scaffolds for Tissue Engineering

December 1, 2009
Author(s)
Carl G. Simon Jr.
The National Institute of Standards and Technology (NIST) has deployed Reference Material (RM) scaffolds for tissue engineering: a series of well-characterized 3D tissue scaffolds with differing porosities (RM 8395, RM 8396 and RM 8397) (Fig. 1). Customers

Microstructure and Mineral Composition of Dystrophic Calcification Associated with the Idiopathic Inflammatory Myopathies

October 26, 2009
Author(s)
Naomi Eidelman, A Boyde, A.J. Bushby, P.G.T. Howell, Jirun Sun, F.W. Miller, P Robey, Lisa Rider
Calcified deposits are present in 30% of children with juvenile dermatomyositis (JDM) and less frequently in adult dermatomyositis (DM). This study aimed to determine the microstructure, composition and stiffness of these deposits. Specimens were analyzed

Viscoelastic Properties of Confined Polymer Films Measured via Thermal Wrinkling

October 8, 2009
Author(s)
Kirt A. Page, Edwin Chan, Se Hyuk Im, Derek L. Patton, Rui Huang, Christopher Stafford
We present a new measurement technique to quantify the viscoelastic properties of polymer thin films. This approach utilizes thermally-induced surface wrinkling to measure the rubbery modulus and shear viscosity of polymer thin films. Specifically, by

MORPHOLOGY AND FRACTURE OF ENAMEL

September 16, 2009
Author(s)
Sang-Won Myoung, James J. Lee, Paul Constantino, Peter Lucas, Brian R. Lawn
Teeth are remarkable biological structures, brittle but resilient. Here we examine the inter-relation between enamel morphology and crack resistance by sectioning human molar teeth after loading to fracture. The sections reveal that many cracks start from
Displaying 551 - 575 of 1733
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