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Displaying 5776 - 5800 of 74072

Parallel Prefetching for Canonical Ensemble Monte Carlo Simulations

August 25, 2020
Author(s)
Harold Wickes Hatch
In order to enable large-scale molecular simulations, algorithms must efficiently utilize multi-core processors that continue to increase in total core count over time with relatively stagnant clock speeds. Although parallelized molecular dynamics (MD)

X-ray Scattering Studies of Reverse Osmosis Materials

August 25, 2020
Author(s)
Qinyi Fu, Nisha Verma, Benjamin S. Hsiao, Francisco J. Medellin-Rodriguez, Peter Beaucage, Christopher Stafford, Benjamin M. Ocko
Scarcity of freshwater is becoming a world crisis. In a recent annual risk report, the World Economic Forum lists it in their greatest global risk category. Currently, about four billion people live under conditions of severe water scarcity for at least

2019 NIST/ITL Cybersecurity Program Annual Report

August 24, 2020
Author(s)
Patrick D. O'Reilly, Kristina G. Rigopoulos, Larry Feldman, Gregory A. Witte
During Fiscal Year 2019 (FY 2019), from October 1, 2018 through September 30, 2019, the NIST Information Technology Laboratory (ITL) Cybersecurity and Privacy Program successfully responded to numerous challenges and opportunities in security and privacy

Binary pseudorandom array test standard optimized for characterization of large field-of-view optical interferometers

August 24, 2020
Author(s)
Valeriy V. Yashchuk, Sergey Babin, Stefano Cabrini, Weilun Chao, Ulf Griesmann, Ian Lacey, Stefano Marchesini, Keiko Munechika, Carlos Pina-Hernandez, Allen L. Roginsky
Recently, a technique for calibrating the modulation transfer function (MTF) of a broad variety of metrology instrumentation has been demonstrated. This technique is based on test samples structured as one-dimensional binary pseudo-random (BPR) sequences

Calibration of an AC Voltage Source Using a Josephson Arbitrary Waveform Synthesizer at 4 V

August 24, 2020
Author(s)
Nathan E. Flowers-Jacobs, Alain Rufenacht, Anna E. Fox, Paul D. Dresselhaus, Samuel P. Benz
This paper describes a method for calibrating an ac source using a Josephson Arbitrary Waveform Synthesizer (JAWS) by summing the sources in series and tuning the magnitude and phase of the JAWS to null the combined output voltage. The method requires an

Compact DC Josephson Voltage Standard

August 24, 2020
Author(s)
Alain Rufenacht, Anna E. Fox, Grace E. Butler, Charles J. Burroughs, Paul D. Dresselhaus, Robert E. Schwall, Stefan Cular, Samuel P. Benz
This paper presents precision measurements with a prototype cryogen-liquid-free DC Josephson voltage standard that produces a 1 V maximum output. Its cryostat is sufficiently compact that it can be operated on a bench close to devices under test. Compared

Evaluation of an alternative null detector for adapted Wheatstone bridge

August 24, 2020
Author(s)
Shamith U. Payagala, Alana M. Dee, Dean G. Jarrett
The adapted Wheatstone bridge technique has been utilized at National Institute of Standards and Technology (NIST) and other National Metrology Institutes (NMIs) for high resistance measurements. In this work, we evaluate the suitability of a

Evaluation of NMIJ Traveling Dual Source Bridge Using NIST Adapted Wheatstone Bridge

August 24, 2020
Author(s)
Takehiko Oe, Shamith U. Payagala, Dean G. Jarrett, Nobu-Hisa Kaneko
DC high resistance measurement capability has been evaluated using a NMIJ traveling dual source bridge between NIST and NMIJ. The NMIJ bridge determines the resistance ratio by measuring the voltage ratio using a digital multimeter, 3458A. Based on the

Evolution of the Structural Transition in Mo 1-x W x Te 2

August 24, 2020
Author(s)
John A. Schneeloch, Yu Tao, Chunruo Duan, Masaaki Matsuda, Adam A. Aczel, Jaime A. Fernandez-Baca, Guangyong Xu, Jorg C. Neuefeind, Junjie Yang, Despina Louca
The composition dependence of the structural transition between the monoclinic 1T′ and orthorhombic T d phases in the Mo 1-xW xTe 2 Weyl semimetal was investigated by elastic neutron scattering on single crystals up to x ≅ 0:54. First observed in MoTe 2

Linking Theory to Practice: Predicting Ballistic Performance from Mechanical Properties of Aged Body Armor

August 24, 2020
Author(s)
Amanda L. Forster, Dennis D. Leber, Amy E. Engelbrecht-Wiggans, Virginie A. Landais, Allen Chang, Emilien J. Guigues, Guillaume Messin, Michael A. Riley
It has long been a goal of the body armor testing community to establish an individualized, scientific-based protocol for predicting end-of-life of fielded body armor ballistic performance. A major obstacle in achieving this goal is that the test methods

Ohms Law Low-current Calibration System for Ionization Chambers

August 24, 2020
Author(s)
Dean G. Jarrett, Shamith U. Payagala, Ryan P. Fitzgerald, Denis E. Bergeron, Jeffrey T. Cessna, Charles J. Waduwarage Perera, Neil M. Zimmerman
A system for the calibration of electrometers that measure currents from ionization chambers is described. The calibration system uses a 1 GΩ standard resistor in series with a stable voltage source to generate calibration currents from 1 pA to 20 nA

On Data Integrity Attacks against Industrial Internet of Things

August 24, 2020
Author(s)
Hansong Xu, Wei Yu, Xing Liu, David W. Griffith, Nada T. Golmie
Industrial Internet of Things (IIoT) is predicted to drive the fourth industrial revolution through massive interconnection of industrial devices, such as sensors, controllers and actuators, integrating advances in smart machinery and data analytics driven

Ultrafast waveform metrology: A first international comparison

August 24, 2020
Author(s)
Mark Bieler, Paul Struszewski, Ari Feldman, Jeffrey Jargon, Paul D. Hale, Pengwei Gong, Wen Xie, Chuntao Yang, Zhigang Feng, Kejia Zhao, Zhijun Yang
We report on the first international comparison in ultrafast waveform metrology. To this end, the frequency and time responses of a photodiode with a nominal bandwidth of 100 GHz have been measured by several National Metrology Institutes during the last

Zero-Compensation Josephson Arbitrary Waveform Synthesizer at 1.33 V

August 24, 2020
Author(s)
Nathan E. Flowers-Jacobs, Akim Babenko, Anna E. Fox, Justus A. Brevik, Paul D. Dresselhaus, Samuel P. Benz
This paper describes the generation of a quantum-based rms output voltage of 1.332 V using an ac-coupled Josephson Arbitrary Waveform Synthesizer (JAWS) without any low-frequency compensation current biases, that is, in a 'zero-compensation' (ZC) mode. Low

Low global-warming-potential refrigerant CH2F2 (R-32): Integration of a radiation heat loss correction method to accurately determine experimental flame speed metrics

August 22, 2020
Author(s)
Gregory T. Linteris, Raik Hesse, Lukas Berger, Michael Hegetschweiler, Heinz Pitsch, Joachim Beeckmann
Due to their high global warming potential (GWP), hydrofluorocarbon refrigerants (HFCs) are systematically being phased out. Replacements with low GWP exist, but give rise to safety hazards as they are found to be mildly flammable. The assessment of the

The Design of an Instrument to Realize Small Torque at NIST

August 22, 2020
Author(s)
Leon S. Chao, Rafael Marangoni, Frank C. Seifert, Darine El Haddad, Jon R. Pratt, David B. Newell, Stephan Schlamminger
After the recent redefinition of the International System of Units (SI), torque no longer needs to be traceable to a calibrated mass in a gravitational field suspended from a known lever arm and disseminated through a chain of torque transducers.An SI

Nesting and Scheduling Problems for Additive Manufacturing: A Taxonomy and Review

August 21, 2020
Author(s)
Yosep Oh, Paul Witherell, Yan Lu, Timothy A. Sprock
With the trends of Industry 4.0 spanning physical and virtual worlds, Additive Manufacturing (AM) has been the mainstream for realizing complex geometries designed in computers. Meanwhile, a considerable number of AM studies have focused on effectively
Displaying 5776 - 5800 of 74072