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Displaying 26601 - 26625 of 73832

Partitioning of Persistent Organic Pollutants (POPs) between Blubber and Blood of Wild Bottlenose Dolphins: Implications for Biomonitoring and Health

June 15, 2010
Author(s)
Jennifer Yordy, John R. Kucklick, Randall S. Wells, Brian C. Balmer, Lori Schwacke, Teresa Rowles
Biomonitoring of wild cetaceans for persistent organic pollutants (POPs) is heavily reliant on concentrations determined in blubber, and there are few data relating blubber concentrations and levels in blood. Matched blubber and plasma samples (n=56) were

Remembering Paul Garabedian

June 15, 2010
Author(s)
Geoffrey B. McFadden
Paul R. Garabedian, a leader in the field of computational science, passed away on May 13th, 2010, at his home in Manhattan at the age of 82 after a long battle with cancer. During the course of sixty years of research on the faculties at Stanford and New

Role of Nanoparticles in Life Cycle of Nanocomposites

June 15, 2010
Author(s)
Xiaohong Gu, Guodong Chen, Minhua Zhao, Stephanie S. Watson, Paul E. Stutzman, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin
The objective of this study is to investigate the role of ZnO nanoparticles in the life cycle of a waterborne polyurethane (PU) nanocomposite during UV exposure. The effects of loadings and sizes of ZnO nanoparticles on photodegradation of ZnO/PU films

Sensitivity scaling of dual frequency comb spectroscopy

June 15, 2010
Author(s)
Ian R. Coddington, William C. Swann, Nathan R. Newbury
Coherent dual comb spectroscopy can harness many inherent strengths of frequency combs to provide high-resolution, high-accuracy measurements of a sample response (in both magnitude and phase) on a single detector. We will discuss the noise scaling

Shape comparison between 0.4 ym to 2.0 ym and 20 ym to 60 ym cement particles

June 15, 2010
Author(s)
L Holzer, R Flatt, S.T. Erodgan, Jeffrey W. Bullard, Edward Garboczi
Portland cement powder has a wide particle size distribution, from approximately 0.1 υm to 60 υm. This wide powder size distribution arises via the grinding of much larger clinker particles in fact, several percent of the world s energy expenditures are

Statistical Modeling of Harvestable Kinetic Energy for Wearable Medical Sensors

June 15, 2010
Author(s)
Nathalie Yarkony, Kamran Sayrafian, Antonio Possolo
Energy Harvesting (EH) refers to the process of capturing and storing energy from external sources or ambient environment. Kinetic energy harvested from the human body motion seems to be one of the most convenient and attractive solution for wearable

Test Collection Diagnosis and Treatment

June 15, 2010
Author(s)
Ian M. Soboroff
Test collections are a mainstay of information retrieval research. Since the 1990s, large reusable test collections have been developed in the context of community evaluations such as TREC, NTCIR, CLEF, and INEX. Recently, advances in pooling practice as

Tunable laser spectroscopy referenced with dual frequency combs

June 15, 2010
Author(s)
Fabrizio R. Giorgetta, Ian R. Coddington, Esther Baumann, William C. Swann, Nathan R. Newbury
Frequency combs provide broadband spectroscopic measurements with high frequency accuracy and precision. However, because the comb power is distributed over a broad spectrum, the sensitivity can be low unless some form of multiplexed detection or cavity

FRACTURE OF TOOTH ENAMEL FROM INCIPIENT MICROSTRUCTURAL DEFECTS

June 14, 2010
Author(s)
H Chai, James J. Lee, Brian R. Lawn
We present definitive evidence for crack growth from internal defects called 'tufts' in human enamel. Side walls of slices sawn from extracted human teeth are observed during loading to 'failure'. 'Longitudinal' and 'transverse' slices (parallel and normal

Interlaboratory Comparison of Traceable Atomic Force Microscope Pitch Measurements

June 14, 2010
Author(s)
Ronald G. Dixson, Donald Chernoff, Shihua Wang, Theodore V. Vorburger, Ndubuisi G. Orji, Siew-Leng Tan, Joseph Fu
The National Institute of Standards and Technology (NIST), Advanced Surface Microscopy (ASM), and the National Metrology Centre (NMC) of the Agency for Science, Technology, and Research (A*STAR) in Singapore have undertaken a three-way interlaboratory

Introduction to Surface Finish Metrology

June 14, 2010
Author(s)
Theodore V. Vorburger
We discuss the range of methods available to measure surface finish and emphasize the methods of stylus profiling and various types of optical profiling. Documentary standards for measurement of surface texture and comparisons between methods are also

Observation of Transparency of Erbium-doped Silicon nitride in photonic crystal nanobeam cavities

June 14, 2010
Author(s)
Yiyang Gong, Maria Makarova, Selcuk Yerci, Rui Li, Martin Stevens, Burm Baek, Sae Woo Nam, Luca Dal Negro, Jelena Vuckovic
One dimensional nanobeam photonic crystal cavities are fabricated in an Er-doped amorphous silicon nitride layer. Photoluminescence from the cavities around 1.54 mm is studied at cryogenic and room temperatures at different optical pump powers. The

Real Time Data Acquisition Platform for Pulsed Measurements

June 14, 2010
Author(s)
Sergey V. Polyakov, Alan L. Migdall, Sae Woo Nam
We present an inexpensive and simple data acquisition platform based on Field Programmable Gate Arrays (FPGAs) designed to acquire and characterize fast digital or analog electrical signal real time for processing on a generic personal computer. While the

A New Electronic Verification Method for Vector Network Analyzers

June 13, 2010
Author(s)
Ronald A. Ginley, Dylan F. Williams, Denis X. LeGolvan
The National Institute of Standards and Technology (NIST) has recently introduced a new method for the verification of Vector Network Analyzers (VNAs). The technique is based on the new electronic calibration units that are available from several

Calibrations of Current-to-Voltage Transimpedance Amplifiers Using Electrical Standards

June 13, 2010
Author(s)
Howard W. Yoon, George P. Eppeldauer, Dean G. Jarrett, Thomas C. Larason, Wan-Seop Kim
For photocurrent measurements with low uncertainties, a wide-dynamic range current-to-voltage converter traceable to resistance standards has been developed at the NIST. The design and calibration of the converter standard are described. For validation

Comparison of Near-Field Methods at NIST

June 13, 2010
Author(s)
Katherine MacReynolds
A comparison of the planar, spherical and cylindrical near-field techniques was completed at the National Institute of Standards and Technology (NIST) for a Ku-band cassegrain reflector antenna. This paper discusses the measurement results for the near-to

Design of the NIST 10 V programmable Josephson voltage standard system

June 13, 2010
Author(s)
Charles J. Burroughs, Paul Dresselhaus, Alain Rufenacht, Mike Elsbury, Samuel Benz
NIST has developed and implemented a new Programmable Josephson Voltage Standard (PJVS) that operates at 10 V. This next-generation system is optimized for both dc metrology and stepwise-approximated ac voltage measurements for frequencies up to a few

Development and investigation of intrinsically shunted junction series arrays for ac Josephson voltage standards

June 13, 2010
Author(s)
Johannes Kohlmann, Franz Mueller, Oliver F. kieler, D. Schleussner, B Egeling, Ralf Behr, David I. Olaya, Paul Dresselhaus, Samuel Benz
Different types of intrinsically shunted Josephson junctions have been developed and inves¬tigated for ac voltage standard applications at PTB. The first type for generation of voltages up to 10 V is driven by a 70 GHz sinusoidal microwave signal and

Development of a Four-channel System for Johnson Noise Thermometry

June 13, 2010
Author(s)
Alessio Pollarolo, Jifeng Qu, Horst Rogalla, Paul Dresselhaus, Samuel Benz
Long integration time is necessary to reach low uncertainty when measuring temperature through Johnson Noise Thermometry (JNT). The main goal of the NIST JNT experiment is to achieve a 6 10-6 relative uncertainty in the measurement of the water triple

Error in calorimetric effective efficiency measurements due to DC losses

June 13, 2010
Author(s)
Thomas P. Crowley
A phenomenon in which DC loss in a transfer standard results in incorrect calorimetric effective efficiency measurements is described. The DC loss occurs within the 4-wire leads of the transfer standard or its connector. It therefore affects calorimetric
Displaying 26601 - 26625 of 73832
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