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Displaying 20551 - 20575 of 74186

The Importance of Entropy to Information Security

February 3, 2014
Author(s)
Apostol T. Vassilev, Timothy Hall
The strength of cryptographic keys is an active challenge in academic research and industrial practice. In this paper we discuss the entropy as fundamentally important concept for generating hard-to-guess, i.e., strong, cryptographic keys and outline the

Time Measurement

February 3, 2014
Author(s)
Michael A. Lombardi
An overview of time metrology, with emphasis on time interval measurements, and time synchronization. It covers the evolution of clocks and timekeeping, time scales, the fundamentals of time measurement, and the various time transfer technique used to

Ultra-Sensitive Chip-Based Photonic Temperature Sensor Using Ring Resonator Structures

February 3, 2014
Author(s)
Haitan Xu, Mohammad Hafezi, Jingyun Fan, Jacob Taylor, Gregory F. Strouse, Zeeshan Ahmed
Temperature is one of the most measured quantity in the world, second only to time. Recently there has been considerable interest in developing photonic temperature sensors to leverage advancements in frequency metrology. Here we show that Silicon based

Dynamic Spectrum Access: Current State of the Art and Future Challenges

February 2, 2014
Author(s)
Anirudha Sahoo, Michael R. Souryal
Dynamic Spectrum Access (DSA) is emerging as a promising technology to mitigate the spectrum scarcity caused by static frequency allocations. Despite the clear need for more efficient allocation, however, DSA faces a number of challenges, chief among them

A comparison of literature models for the oxidation of normal heptane

February 1, 2014
Author(s)
David A. Sheen, Wing Tsang
The development of detailed chemical kinetic models has proceeded unabated since the pioneering work of Dixon-Lewis and coworkers forty-five years ago. In that time, computational power has increased ten million-fold, and yet, we do not have a consensus on

A New NIST Primary Standardization of 18F

February 1, 2014
Author(s)
Ryan P. Fitzgerald, Brian E. Zimmerman, Denis E. Bergeron, Jeffrey T. Cessna, Leticia S. Pibida, Denise S. Moreira
A new primary standardization of 18F by NIST is reported. The standard is based on live-timed beta- gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST 3H efficiency

Structure and Properties of a-NaFeO 2 -type Ternary Sodium Iridates

February 1, 2014
Author(s)
Kristen Baroudi, Cindi Yim, Hui Wu, Qingzhen Huang, John H. Roudebush, Eugenia Vavilova, Hans-Joachim Grafe, Vladislav Kataev, Bernd Buechner, Huiwen Ji, Changyang Kuo, Zhiwei Hu, Tun-Wen Pi, Chiwen Pao, Jyhfu Lee, Daria Mikhailova, Liu Hao Tjeng, R. J. Cava
The synthesis, structure, and elementary magnetic and electronic properties are reported for layered compounds of the type Na 3-xMIr 2O 6 and Na 3-xM 2IrO 6, where M is a transition metal from the 3d series (M=Zn, Cu, Ni, Co, Fe and Mn). The rhombohedral

The effect of Acetobacter sp. and a sulfate-reducing bacterial consortium from ethanol fuel environments on fatigue crack propagation in pipeline and storage tank steels

February 1, 2014
Author(s)
Jeffrey W. Sowards, Charles H. Williamson, Timothy S. Weeks, Joseph D. McColskey, John R. Spear
This study evaluated the effects of microbiologically influenced corrosion (MIC) on fatigue crack growth of candidate materials useful in expanding bioethanol usage including: a storage tank steel (ASTM A36) and two pipeline steels (API 5L X52 and X70)

The Hafnium-Platinum Phase Diagram

February 1, 2014
Author(s)
Judith K. Stalick, Richard M. Waterstrat
Phase relationships were determined in the Hf-Pt system at temperatures up to 1690°C using both metallographic and neutron Rietveld refinement techniques. An unusual displacive transformation is observed 200 °C in the rhombohedral compound Hf 3Pt 4
Displaying 20551 - 20575 of 74186
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