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Displaying 826 - 850 of 1856

THE ROLE OF TOOTH ENAMEL MECHANICAL PROPERTIES IN PRIMATE DIETARY ADAPTATION

June 27, 2012
Author(s)
Paul Constantino, James J. Lee, Yvonne B. Gerbig, Adam Hartstone-Rose, Mauricio Talebi, Brian R. Lawn, Peter Lucas
Primate teeth adapt to the physical properties of foods in a variety of ways including changes in occlusal morphology, enamel thickness, and overall size. We conducted a comparative study of extant primates to examine whether their teeth also adapt to

RESONANCE ENERGY TRANSFER AS A TOOL FOR PROBING INTERFACE FORMATION IN NANOCOMPOSITES

June 24, 2012
Author(s)
Mauro Zammarano, Edward D. McCarthy, Douglas M. Fox, Paul H. Maupin, Li Piin Sung, Yeon S. Kim
One of the most enduring problems in the evolution of science and technology using nanoscale materials is the characterization of their morphology in macroscopic systems.1 This involves spatial and orientation distribution, which may be multimodal and

Solid-Phase Synthesis of Ammonium Ionenes

June 24, 2012
Author(s)
Matthew T. Hunley, Kathryn L. Beers
Ionenes are polyelectrolytes with the charge along the polymer backbone. These polymers possess a precisely-defined charge density, making them ideal as physical crosslinkers for high performance elastomers as well as gene transfection agents. However

Synthesis and characterization of model crosslinked polyamide films for water purification

June 24, 2012
Author(s)
Peter M. Johnson, Edwin Chan, Jun Y. Chung, Junghyun Lee, Christopher Stafford
Reverse osmosis (RO) and nanofiltration (NF) membranes are comprised of a dense active layer supported by a porous support. Commercial active layer are highly crosslinked polyamides that are formed through interfacial polymerization directly on the support

Photo-induced Surface Transformation of Silica Nanocomposites

June 22, 2012
Author(s)
Justin M. Gorham, Tinh Nguyen, Coralie Bernard, Deborah S. Jacobs, Richard D. Holbrook
The physicochemical, UV-induced surface modifications to silica nanoparticle (SiNP) - epoxy composites have been investigated. The silica nanocomposites (SiNCs) were prepared using a two-part epoxy system with 10 % mass fraction of SiNPs and exposed to

Physical Model for Random Telegraph Noise Amplitudes and Implications

June 12, 2012
Author(s)
Richard G. Southwick, Kin P. Cheung, Jason P. Campbell, Serghei Drozdov, Jason T. Ryan, John S. Suehle, Anthony Oates
Random Telegraph Noise (RTN) has been shown to surpass random dopant fluctuations as a cause for decananometer device variability, through the measurement of a large number of ultra-scaled devices [1]. The most worrisome aspect of RTN is the tail of the

Tensile behavior of single PPTA fibers measured by the Kolsky bar using the direct fiber clamping method

June 11, 2012
Author(s)
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Richard L. Rhorer, Kirk D. Rice, Gale A. Holmes
The Kolsky bar test has been widely used in measuring material behavior under high strain rate conditions. In particular, this methodology has been used to characterize the high strain rate behavior of polymer and polymer composites during ballistic impact

Pronounced micro-segregation in a sorbitol water mixture observed through variable temperature neutron scattering

May 16, 2012
Author(s)
Shin G. Chou, Sheila Khodadadi, Joseph E. Curtis, Susan Krueger, Evgenyi Shalaev, Alan Soper, Andy Fitch, T Narayanan, Michael Szutucki, Marcus T. Cicerone
In this study, we use small and wide angle X-ray and neutron scattering measurements, to study the structure of concentrated sorbitol solutions and glasses at different temperatures. The analysis of the data suggests the water forms clusters with a

Optimization of Imaging Polymer Based Scaffolds Using X-Ray Microcomputed Tomography

May 15, 2012
Author(s)
David E. Morris, Melissa L. Mather, Carl Simon Jr., John A. Crowe
The performance of polymer based scaffolds used in regenerative medicine is linked to their structural properties and as such strategies for structural characterization of scaffolds have been developed. X-ray microscopic computed tomography (X-ray micro CT

Neutron reflectivity characterization of the photoacid reaction-diffusion latent and developed images of molecular resists for extreme-ultraviolet lithography

May 11, 2012
Author(s)
Vivek M. Prabhu, Shuhui Kang, Wen-Li Wu, Sushil K. Satija, Christopher K. Ober, Jing Sha, Peter V. Bonnesen
Lithographic feature size requirements have approached a few radius of gyration of chemically-amplified photoresist polymers used in thin film patterning. Further, the feature dimensions are commensurate with the photoacid diffusion length that defines the

An Overview of Polymer Electrolyte Membranes for Fuel Cell Applications

May 7, 2012
Author(s)
Brandon W. Rowe, Kirt A. Page
While fuel cells have receive considerable attention over the last 10-20 years, the history of hydrogen fuel cells dates back to 1838. It would take more than a century before polymers would be impletmented as an electrolyte for proton transport (1955) and

Inelastic Neutron Scattering on Polymer Electrolytes for Lithium-Ion Batteries

May 7, 2012
Author(s)
Huagen H. Peng, Madhu Sudan Tyagi, Kirt A. Page, Christopher Soles
The relationship between ion transport and polymer dynamics is central to the pursuit of solid polymer electrolytes for lithium batteries. This understanding is critical to achieve solid polymer electrolyte systems of sufficiently high ion conductivities

Understanding Interfacial Structure of Proton Exchange Membrane Fuel Cells

May 7, 2012
Author(s)
Kirt A. Page, Sangcheol Kim, Christopher L. Soles
Although substantial improvements have been demonstrated for fuel cell technology over the past decade, the major technical challenges as associated with cost and durability should be overcome for fuel cells to compete in real markets and achieve wide

Gas-Foamed Scaffold Gradients for Combinatorial Screening in 3D

May 1, 2012
Author(s)
Carl G. Simon Jr., Kaushik Chatterjee, Alison M. Kraigsley, Joachim Kohn, Durgadas Bolikal
Current methods for screening cell-material interactions typically utilize two-dimensional (2D) culture format where cells are cultured on flat surfaces. However, there is a need for combinatorial and high-throughput screening methods to systematically

Osteoblast Response to Serum Protein Adsorption in 3D Polymer Scaffolds

May 1, 2012
Author(s)
Carl G. Simon Jr., Girish Kumar, Kaushik Chatterjee, Stevephen Hung
Protein adsorption is known to direct biological response to biomaterials and is important in determining cellular response in tissue scaffolds. In this study we investigated the effect of adsorbed serum proteins on cell attachment and proliferation in

SOLID-SUPPORTED ENZYME CATALYST MODELS FOR RING-OPENING POLYMERIZATION

April 27, 2012
Author(s)
Sara V. Orski, Santanu S. Kundu, Kathryn L. Beers, Richard A. Gross
The enzyme Candida antarctica Lipase B (CAL B), immobilized on a crosslinked poly(methyl methacrylate) (PMMA) support, catalyzes the ring-opening polymerization of ε-caprolactone to make biodegradable polyesters. Weak hydrophobic interactions of CAL B

Materials Challenges in Carbon Mitigation Technologies

April 24, 2012
Author(s)
Laura Espinal, Bryan D. Morreale
Thermochemical conversion of fossil fuels currently dominates the national and global energy portfolio, with the most notable being the stationary power production and transportation vehicles sectors. As global energy demand continues to increase

Shear and dilational interfacial rheology of surfactant-stabilized droplets

April 5, 2012
Author(s)
Jeffrey D. Martin, Kendra A. Erk, Jonathan T. Schwalbe, Frederick R. Phelan Jr., Steven Hudson
A new measurement method is suggested that is capable of probing the shear and dilational interfacial rheological responses of small droplets, those of size comparable to real emulsion applications. Freely suspended aqueous droplets containing surfactant

OVERVIEW OF THE TESTING PROGRAM ON FIBERS USED IN BALLISTIC APPLICATIONS

April 4, 2012
Author(s)
Amanda L. Forster, Haruki Kobayashi, Jae H. Kim, Michael A. Riley, Joy Dunkers, Scott Wight, Kirk D. Rice, Gale A. Holmes
The goal of this paper and presentation is to give an overview of the research effort to date being conducted at the National Institute of Standards and Technology on polymeric fibers used in soft body armor (SBA) and a discussion of future directions. The

OOF3D: An Image-Based Finite Element Solver for Materials Science

March 28, 2012
Author(s)
Valerie R. Coffman, Andrew C. Reid, Stephen A. Langer, Gunay Dogan
Recent advances in experimental techniques (micro CT scans, automated serial sectioning, electron back-scatter diffraction, synchrotron radiation x-rays) have made it possible to characterize the full, three dimensional structure of real materials. Such
Displaying 826 - 850 of 1856