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Displaying 2026 - 2050 of 143780

A Microgravity Flame Speed Study on Refrigerant Mixtures of 2,3,3,3-Tetrafluoropropene (R1234yf) and Difluoromethane (R32)

September 25, 2023
Author(s)
Raik Hesse, Roman Glaznev, Christian Schwenzer, Valeri I. Babushok, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
Today's hydrofluorocarbon (HFC) refrigerants are designed to have a low global warming potential (GWP), resulting in fast atmospheric decomposition and increased reactivity. This causes them to be mildly flammable. The laminar flame speed SL,u ranks

Cybersecurity Framework Profile for Hybrid Satellite Networks (HSN)

September 25, 2023
Author(s)
Dan Mamula, Karri Meldorf, Joseph Brule, O'Ryan Lattin, John Wiltberger, Sam Sepassi, Rory Jennings, Chris Thorpe, John Dombrowski, Jim McCarthy
The space sector is transitioning towards Hybrid Satellite Networks (HSN) which is an aggregation of independently owned and operated terminals, antennas, satellites, payloads, or other components that comprise a satellite system. The elements of an HSN

Data Reduction Considerations for Spherical Constant Volume Flames of R32(CH2F2) with Air

September 25, 2023
Author(s)
Michael Hegetschweiler, Lukas Berger, Raik Hesse, Joachim Beeckmann, Chaimae Bariki, Heinz Pitsch, Gregory T. Linteris
The present work explores data reduction techniques for the measurement of the laminar burning velocities of R32(CH2F2)-air using a constant volume combustion device in which the pressure-time history is the only measured parameter. To allow clear

Elucidating the challenges in extracting ultra-slow flame speeds in a closed vessel - A CH2F2 microgravity case study using optical and pressure-rise data

September 25, 2023
Author(s)
Raik Hesse, Chaimae Bariki, Michael Hegetschweiler, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
Refrigerants with a low global warming potential (GWP) possess mild flammability. Hence, a fundamental understanding of their combustion characteristics is required to assess their fire-hazardous potential. The laminar burning velocity is one fundamental

Simultaneous Particle Image Velocimetry and Schlieren Measurements of Slow-burning Flames

September 25, 2023
Author(s)
Christian Schwenzer, Raik Hesse, Roman Glaznev, Valeri I. Babushok, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
The measurement of laminar flame speed is an essential factor in determining the reactivity, exothermicity, and diffusivity of a combustible mixture. In this study, the Schlieren method and Particle Image Velocimetry (PIV) were utilized simultaneously to

High Sulfur Loading and Capacity Retention in Bilayer Garnet Sulfurized-Polyacrylonitrile/Lithium-Metal Batteries with Gel Polymer Electrolytes

September 24, 2023
Author(s)
Changmin Shi, Saya Takeuchi, George Alexander, Tanner Hamann, Jonathan O'Neill, Joseph A. Dura, Eric Wachsman
Abstract The cubic‐garnet (Li 7La 3Zr 2O 12, LLZO) lithium–sulfur battery shows great promise in the pursuit of achieving high energy densities. The sulfur used in the cathodes is abundant, inexpensive, and possesses high specific capacity. In addition

Strain-activated stimulated emission from multilayer MoSe2 in a narrow operation window

September 24, 2023
Author(s)
Yuankun Lin, Noah Hurley, Steve Kamau, Evan Hathaway, Yan Jiang, Roberto Gonzalez Rodriguez, Sinto Varghese, Sergiy Krylyuk, Albert Davydov, Yuanxi Wang, Anupama Kaul, Jingbiao Cui
Herein, photoluminescence (PL) and fluorescence lifetime imaging (FLIM) in multilayer MoSe2 are studied. Strain-activated stimulated emission via defect levels in multilayer MoSe2 under laser excitation is observed, for the first time in defects of

The Generating Series of Support Minors MinRank Ideals

September 24, 2023
Author(s)
Daniel Smith-Tone
The support minors method has become indispensable to cryptanalysts in attacking various post-quantum cryptosystems in the areas of multivariate cryptography and rank-based cryptography. The complexity analysis for support minors minrank calculations is a

Assessing the Feasibility of Achieving Functional Recovery Goals through Seismic Retrofit of Existing Reinforced Concrete Buildings

September 23, 2023
Author(s)
Negar Mohammadgholibeyki, Maria Jose Echeverria, Amir Safiey, Dustin Cook, Maria Koliou, ABBIE LIEL
Damage from past earthquakes has significantly impeded post-earthquake building function, threatening community resilience, and motivating consideration of functional recovery in building design and assessment. This study examines whether it is feasible to

BABAR-ERI: Black Array of Broadband Absolute Radiometers - Earth Radiation Imager

September 22, 2023
Author(s)
Chris Yung, Cameron Straatsma, Nathan Tomlin, David Harber, Odele Coddington, John H. Lehman, Michelle Stephens
BABAR-ERI is being developed for a CubeSat capable of imaging the Earth's outgoing longwave radiation with a 1 km ground sample distance (GSD) using a push-broom imager. The detector is a silicon micromachined 32-pixel linear array of electrical

Harmonic dependence of thermal magnetic particle imaging

September 22, 2023
Author(s)
Thinh Bui, Mark-Alexander Henn, Weston L. Tew, Megan Catterton, Solomon I. Woods
Advances in instrumentation and tracer materials are still required to enable sensitive and accurate 3D temperature monitoring by magnetic particle imaging. We have developed a magnetic particle imaging instrument to observe temperature variations using

Plumbing System Models for a Set of Reference Buildings

September 21, 2023
Author(s)
Stephen Zimmerman, Andrew K. Persily
Reference buildings have been defined previously and successfully applied to energy and indoor air quality analyses, providing a platform for consistent comparisons between different building design and operation scenarios. One such set of reference

Primary Sound Standard Based On Dynamic Fabry Perot Interferometry

September 21, 2023
Author(s)
Akobuije Chijioke, Richard A. Allen, Steven E. Fick, Benjamin Reschovsky, Jared Strait, Randall P. Wagner
We describe an optical sound standard in which the sound pressure is measured by using a high-finesse optical cavity to observe the induced change in the refractive index of the medium (acousto-optic effect). The optical refractive index of a substance

Towards Ontologizing a Digital Twin Framework for Manufacturing

September 21, 2023
Author(s)
Milos Drobnjakovic, Guodong Shao, Ana Nikolov, Boonserm Kulvatunyou, Simon P. Frechette, Vijay Srinivasan
This paper presents a timely opportunity to ontologize a digital twin frame-work for manufacturing using recently published international standards and proposes a collaborative research effort to accomplish this task. The ISO/IEC 21838 series of standards

G2Aero: A Python package for separable shape tensors

September 20, 2023
Author(s)
Olga Doronina, Zachary J. Grey, Andrew Glaws
G2Aero is a Python package for the design and deformation of discrete planar curves and tubular surfaces using a geometric data-driven approach. G2Aero utilizes a topology of product manifolds: the Grassmannian---the set of 2-dimensional subspaces in Rn--

High accuracy, high dynamic range optomechanical accelerometry enabled by dual comb spectroscopy

September 20, 2023
Author(s)
David Long, Jasper Stroud, Benjamin Reschovsky, Yiliang Bao, Feng Zhou, Thomas W. LeBrun, David Plusquellic, Jason Gorman, Sean Bresler
Cavity optomechanical sensors offer exceptional sensitivity but interrogating the cavity motion with high accuracy and dynamic range has proven to be challenging. Here we employ a dual optical frequency comb spectrometer to readout a cavity optomechanical

ICSSC Biennial Progress Report for 2020: Report on Progress Towards Implementation of Executive Order 13717: Establishing a Federal Earthquake Risk Management Standard - Reporting Period: February 2, 2018 to February 1, 2020

September 20, 2023
Author(s)
John Harris, Steven McCabe
Executive Order (EO) 13717: Establishing a Federal Earthquake Risk Management Standard establishes minimum seismic requirements for new and existing buildings that will be constructed, altered, leased, financed, or regulated by the Federal Government
Displaying 2026 - 2050 of 143780
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