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Displaying 18126 - 18150 of 74849

The Prehydration of Cement and Its Mitigation

December 6, 2014
Author(s)
Julyan Stoian, Tandre Oey, Jeffrey W. Bullard, Jian Huang, Aditya Kumar, Magdalena Balonis, Narayanan Neithalath, Gaurav Sant
Ordinary portland cement (OPC) prehydrates during storage or handling in moist environments, forming hydration products on or near its particles' surfaces. Prehydration is known to reduce OPC reactivity, but the extent of prehydration has not yet been

Toward a New Evaluation of the Neutron Standards

December 6, 2014
Author(s)
Allan D. Carlson, V G. Pronyaev, R. Capote, G M. Hale, F. J. Hambsch, T Kawano, S. Kunieda, R O. Nelson, D. Neudecker, P Schillebeeckx, S Simakov, D L. Smith, X Talou, A Wallner, W Wang
A new version of the ENDF/B library has been planned. The first step in producing this new library is evaluating the neutron standards. An evaluation is now underway with support from a Data Development Project of the IAEA. In addition to the neutron cross

An Equation of State for the Thermodynamic Properties of Cyclohexane

December 5, 2014
Author(s)
Yong Zhou, Jun Liu, Steven Penoncello, Eric Lemmon
In this work, an equation of state for cyclohexane has been developed using the Helmholtz energy as the fundamental property with independent variables of density and temperature. Multi-property fitting technology was used to fit the equation of state that

Junction Yield Analysis for 10 V Programmable Josephson Voltage Standard Devices

December 5, 2014
Author(s)
Anna E. Fox, Paul D. Dresselhaus, Alain Rufenacht, Aric W. Sanders, Samuel P. Benz
Analysis of the Josephson junction yield in the National Institute of Standards and Technology 10 V Programmable Josephson Voltage Standard (PJVS) has been performed by fabricating and measuring over 25 million Nb/NbxSi1-x/Nb junctions. Using the 265,116

Morphological Stability

December 5, 2014
Author(s)
Robert F. Sekerka, Sam R. Coriell, Geoffrey B. McFadden
The theory of morphological stability provides a dynamical analysis of the stability of the interface that separates phases during a phase transformation. We focus on crystallization from either a pure or alloy melt. One solves the governing equations for

Analysis of One-Minute Potentially Available Fluoride from Dentifrice

December 4, 2014
Author(s)
Clifton Carey, Erin Holahan
Previous reports found that some fluoride containing dentifrices do not release effective concentrations of fluoride during brushing. Failure to release fluoride can be due to dentifrice matrix components that interfere with the solubilization of the

Costs and Cost Effectiveness of Additive Manufacturing

December 4, 2014
Author(s)
Douglas Thomas, Stanley W. Gilbert
The use of additive manufacturing has increased significantly in previous years. Additive manufacturing is used by multiple industry subsectors, including motor vehicles, aerospace, machinery, electronics, and medical products. Currently, however, additive

GPS Measurements Anomaly and Continuous GPS Carrier-Phase Time Transfer

December 4, 2014
Author(s)
Jian Yao, Judah Levine
The wide application of GPS carrier-phase (CP) time transfer is limited by the problem of boundary discontinuity (BD). The discontinuity has two categories. One is "day boundary discontinuity", which has been studied a lot and can be solved by a few

High Throughput Screening Tools for Thermoelectric Materials

December 4, 2014
Author(s)
Winnie K. Wong-Ng, Yonggao Yan, Makoto Otani, Joshua B. Martin, Kevin R. Talley, Sara C. Barron, David L. Carroll, C Hewitt, Howard Joress, Evans L. Thomas, Martin L. Green, Xinfeng Tang
A suite of complementary high-throughput screening systems for combinatorial films was developed at NIST to facilitate the search for efficient thermoelectric materials. These custom-designed capabilities include a facility for combinatorial thin film

International Comparisons of Network Time Protocol Servers

December 4, 2014
Author(s)
Michael A. Lombardi, Judah Levine, Jose M. Lopez, Francisco Jimenez, John Bernard, Marina Gertsvolf, Harold Sanchez, Oscar G. Fallas, Liz C. Hernandez Ferero, Ricardo de Carvalho, Mario Fittipaldi, Raul Solis, Franklin Espejo
This paper describes a recently designed system that measures the time transmitted by network time protocol (NTP) servers located in North, Central, and South America. Direct measurements of the time transmitted by each server are obtained by comparing the

Measured Ionosphere Delay Correction for Code-Based GPS Time Transfer

December 4, 2014
Author(s)
Victor S. Zhang, Zhiqi Li
Nowadays, more and more dual-frequency, multichannel receivers are used in GPS time and frequency transfer applications. Instead of using the modeled ionosphere delay correction or using the IGS ionospheric map, we can obtain the ionosphere delay

Periodic dynamics, localization metastability, and elastic interaction of colloidal particles with confining surfaces and helicoidal structure of cholesteric liquid crystals

December 4, 2014
Author(s)
Michael C. Varney, Qiaoxuan Zhang, Mykola Tasinkevych, Nuno M. Silvestre, Kristine A. Bertness, Ivan I. Smalyukh
Although nematic and cholesteric liquid crystals are three-dimensional fluids, they also possess long- range orientational ordering of their constituent molecules, supporting both topological defects and chiral superstructures. Implications of this

The Use of Cause-and-Effect Analysis to Design a High Quality Nano-Cyto-Toxicology Assay

December 4, 2014
Author(s)
Matthias Rosslein, John T. Elliott, Marc L. Salit, Elijah Petersen, Cordula Hirsch, Harald Krug, Peter Wick
An important consideration in developing standards and regulations that govern the production and use of commercial nanoscale materials is the development of robust and reliable measurements to assess potential biological effects of these nanomaterials

Kinetic Polymer Arrest in Percolated SWNT Networks

December 3, 2014
Author(s)
Rana NMN Ashkar, Mansour Abdul Baki, Madhu Sudan Tyagi, Antonio Faraone, Paul Butler, Ramanan Krishnamoorti
The inclusion of single-wall carbon nanotubes (SWNT) in a polymer, with interchain distances comparable to the SWNT diameter, can significantly perturb the structural and dynamical properties of interfacial polymeric units. For SWNT concentrations above

Polaron-Mediated Spin Correlations in Metallic and Insulating La 1-x A x MnO 3 (A=Ca,Sr, or Ba)

December 3, 2014
Author(s)
Joel Helton, Daniel M Pajerowski, Yiming Qiu, Yang Zhao, Dmitry A. Shulyatev, Yakov M. Mukovskii, Georgii L. Bychkov, Sergei N. Barilo, Jeffrey W. Lynn
Neutron spectroscopy measurements reveal short-range spin correlations near and above the ferromagnetic-paramagnetic phase transition in manganite materials of the form La 10zA xMnO 3, including samples with an insulating ground state as well as colossal

Quantum Critical Fluctuations in the Heavy Fermion compound Ce(Ni^s0.935^Pd 0.065 ) 2 Ge 2

December 3, 2014
Author(s)
C. H. Wang, L. Poudel, A. E. Taylor, J .M. Lawrence, A. D. Christianson, Sung Chang, Jose Rodriguez Rivera, Jeffrey W. Lynn, A. A. Podlesnyak, G. Ehlers, R. E. Baumbach, E. D. Bauer, K. Gofryk, F. Ronning, K. J. McClellan, J. D. Thompson
Inelastic neutron scattering experiments were performed on a single crystal of the heavy Fermion compound Ce(Ni 0.935Pd 0.065) 2Ge 2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). We find that the
Displaying 18126 - 18150 of 74849