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6 results on '"U.S. Naval Research Laboratory, Washington, D. C."'

1. Dual-layer catalyst layers for increased proton exchange membrane fuel cell performance

Author

Marian Chatenet, Laetitia Dubau, Yannick Garsany, Rachel Martin, Benjamin D. Gould, Robert W. Atkinson, Karen E. Swider-Lyons, Excet Incorporation, U.S. Naval Research Laboratory, U.S. Naval Research Laboratory, Washington, D. C., Consortium des Moyens Technologiques Communs (CMTC), Institut National Polytechnique de Grenoble (INPG), Electrochimie Interfaciale et Procédés (EIP), Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI), Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
Materials science, Energy Engineering and Power Technology, Proton exchange membrane fuel cell, chemistry.chemical_element, 02 engineering and technology, Electrolyte, 7. Clean energy, law.invention, Catalysis, law, 0502 economics and business, Gaseous diffusion, 050207 economics, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Renewable Energy, Sustainability and the Environment, 05 social sciences, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Cathode, Dielectric spectroscopy, chemistry, Chemical engineering, 0210 nano-technology, Platinum, Carbon
Abstract

International audience; The use of a dual-layer cathode catalyst layer improves the performance of proton exchange membrane fuel cells. To generate single and dual-layer catalyst layers between the gas diffusion media and proton exchange membrane electrolyte, two commercial carbon-supported platinum catalysts with either a high microporosity carbon (Ketjen Black EC-300J) or a low porosity carbon (XC-72 Vulcan carbon) are utilized. We discovered that dual-layer cathode catalyst layers boost maximum power of fuel cells regardless of carbon porosity directionality, with either high surface area carbon at the proton exchange membrane electrolyte or gas diffusion media interface. At 25% relative humidity, a condition that generally inhibits fuel cell performance, a 20% performance boost is realized when using dual-layer cathode CLs. The electrochemical impedance spectroscopy results indicate that cathodes with dual-layer catalyst layer aid in water management due to lower kinetic activity losses of the Pt and improved hydration of the proton exchange membrane electrolyte.

Published
2021
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2. The Effect of Submicron Second-Phase Particles on the Rate of Grain Refinement in a Copper-Oxygen Alloy During Cold Spray

Author

Sylvie Descartes, Nicolas Brodusch, Richard R. Chromik, Raynald Gauvin, Yinyin Zhang, J. Michael Shockley, Department of Mining and Materials Engineering [Montréal], McGill University = Université McGill [Montréal, Canada], Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and U.S. Naval Research Laboratory, Washington, D. C.

Subjects
Materials science, Alloy, Gas dynamic cold spray, Nucleation, 02 engineering and technology, engineering.material, 01 natural sciences, [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], particle-stimulated nucleation (PSN), Phase (matter), 0103 physical sciences, Materials Chemistry, cold spray, 010302 applied physics, Metallurgy, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Surfaces, Coatings and Films, high-resolution electron backscatter diffraction (EBSD), second-phase particles, Dynamic recrystallization, engineering, Particle, Deformation (engineering), 0210 nano-technology, Electron backscatter diffraction
Abstract

International audience; The effect of non-deformable submicron secondphase particles (d = 200-500 nm) on microstructural refinement during cold spray was examined. Using single particle impact testing, two types of splats were fabricated using two different feedstocks: a Cu-0.21wt.%O powder containing Cu2O second-phase particles and a single-phase Cu. Microstructural evolution analysis using high-resolution electron backscatter diffraction shows grain refinement occurred at a higher rate in the Cu-0.21wt.%O powder. That was due to dynamic recrystallization initiated by particle-stimulated nucleation (PSN). High-strain-rate deformation of cold spray was found to be the key to activate PSN. The present study suggests cold spray is apossible technique to fabricate ultrafine-grained materials by using feedstock containing second-phase particles.

Published
2017
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3. Measurement of Elastic and Rotation Fields during Irreversible Deformation using Heaviside-Digital Image Correlation

Author

François Bourdin, Jean Charles Stinville, Tresa M. Pollock, Damien Texier, McLean P. Echlin, Patrick G. Callahan, Jonathan Cormier, Patrick Villechaise, Valery Valle, Marie-Agathe Charpagne, Zhe Chen, University of California [Santa Barbara] (UCSB), University of California, Institut Pprime (PPRIME), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), U.S. Naval Research Laboratory, U.S. Naval Research Laboratory, Washington, D. C., Institut Clément Ader (ICA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC), ENDOmmagement et durabilité ENDO (ENDO), Département Physique et Mécanique des Matériaux (Département Physique et Mécanique des Matériaux), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Institut Pprime (PPRIME), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), Naval Research Laboratory (NRL), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Photomécanique et analyse expérimentale en Mécanique des solides (PEM), and Département Génie Mécanique et Systèmes Complexes (GMSC)

Subjects
Digital image correlation, Materials science, Elastic Heterogeneity, Strain Localization, Geometry, Scanning Electron Microscopy Digital Image Correlation, 02 engineering and technology, Slip (materials science), Classification of discontinuities, 01 natural sciences, [SPI]Engineering Sciences [physics], 0103 physical sciences, General Materials Science, Micro-volumes, Grain Boundary Sliding, 010302 applied physics, Discontinuities Measurements, Mechanical Engineering, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Elastic and plastic strain, Polycrystalline Nickel-based Superalloys, Mechanics of Materials, Displacement field, Deformation (engineering), Elastic and Plastic Strain, 0210 nano-technology, High Resolution Digital Image Correlation Heaviside-DIC, Electron backscatter diffraction, rotation field
Abstract

International audience; The recent development of the high resolution and discontinuity-tolerant digital image correlation technique enables the extraction of discontinuities within a displacement field. The technique provides quantitative analysis of discontinuities arising from slip, shear bands, cracks, and grain boundary sliding in a variety of material systems, including polycrystalline metallic materials. The discontinuity-tolerant digital image correlation method can be implemented to retrieve not only quantitative discontinuity analysis but also the local strain and rotation fields that operate near these discontinuities. The present implementation includes high-resolution digital image correlation (HR-DIC) measurements collected in a scanning electron microscope for analysis of both the plastic and elastic fields that develop during deformation of polycrystalline metallic materials. The combination of the discontinuity-tolerant DIC technique with the computation of internal gradients enables extraction of non-localized strain and rotation fields during plastic deformation of a nickel-based superalloy. Therefore the lattice rotation/expansion and plastic localization that occur during deformation can be determined in a single experiment. This method is validated using synthetic images with preset deformation, and experimental measurements using the electron back scatter diffraction (EBSD) technique.

Published
2020
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4. Comparison of X-Ray and Electron Radiation Effects on Dark Current Non-Uniformity and Fluctuations in CMOS Image Sensors

Author

Jean-Marc Belloir, Alexandre Le Roch, Cedric Virmontois, Vincent Goiffon, Philippe Paillet, Pierre Magnan, Jeffrey H. Warner, Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE), Centre National d'Études Spatiales - CNES (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Office of Naval Research - ONR (USA), Direction des applications militaires Ile de France - CEA/DAM DIF (Arpajon, France), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Centre National d'Études Spatiales [Toulouse] (CNES), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Naval Research Laboratory (NRL), U.S. Naval Research Laboratory, and U.S. Naval Research Laboratory, Washington, D. C.

Subjects
Nuclear and High Energy Physics, Dark current spectroscopy (DCS), Electric field enhancement (EFE), Total ionizing dose (TID), Electron, Annealing, CMOS image sensor (CIS), 01 natural sciences, Ionizing radiation, law.invention, Annealing, Pinned photodiode (PPD), law, Electric field, 0103 physical sciences, Electron beam processing, Traitement du signal et de l'image, Electrical and Electronic Engineering, Physics, 010308 nuclear & particles physics, X-ray, Electron irradiation, Random telegraph signal (RTS), X-ray irradiation, Displacement damagedose (DDD), Photodiode, Amplitude, Dark current, Nuclear Energy and Engineering, Displacement damage dose (DDD), Darkcurrent, CMOS image sensor (CIS), Atomic physics, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; This article investigates the dark current as well as the dark current random telegraph signal (RTS) after 1-MeV electron, 3-MeV electron, and 10-keV X-ray irradiations in a pinned photodiode CMOS image sensor (CIS). A large range of deposited ionizing dose from 10 to 525 krad(SiO 2 ) is considered. The displacement damage dose deposited through electron irradiation ranges from 60 to 1200 TeV · g -1 . Results on dark current distributions highlight the predominance of the ionizing damage in opposition to the displacement damage induced by the electron irradiations. Moreover, the dark current distributions also suggest that if the ionizing dose is high enough [i.e., beyond 50 krad(SiO 2 )], the trapped positive charges in the silicon oxides create high magnitude electric field regions leading to an electric field enhancement (EFE) of the dark current which is neither present at lower doses nor in pristine image sensors. This EFE mechanism also seems to have a strong influence on the RTS leading to a clear discrepancy from the existing dark current nonuniformity model developed for amplitude distributions in CISs as well as from what is reported in the literature in the more studied ionizing dose range. Annealing treatments after electron irradiations have highlighted the existence of specific population of pixels sharing the same well-defined maximum transition amplitudes (i.e., maximum amplitude between two dark current levels). The results suggest the use of maximum transition amplitude spectroscopy applied to dark current RTS to push forward the investigation on radiation-induced defects creation and identification.

Published
2020
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5. Ultrafast laser inscribed waveguides for mid-infrared interferometry

Author

Arriola, Alexander, Gross, Simon, Ams, Martin, Le Coq, David, Wang, Rongping, Ebendorff-Heidepriem, Heike, Sanghera, Jasbinder, Ireland, Michael, Tuthill, P., Withford, M. J., Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Macquarie University, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Laser Physics Centre-Research School of Physical Sciences and Engineering (LPC), Australian National University (ANU), ARC Centre of Excellence for Nanoscale BioPhotonics, U.S. Naval Research Laboratory, U.S. Naval Research Laboratory, Washington, D. C., Research School of Astronomy and Astrophysics [Canberra] (RSAA), Sydney Institute for Astronomy (SIfA), The University of Sydney, LE COQ, DAVID, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Naval Research Laboratory (NRL)

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, [SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [CHIM.MATE]Chemical Sciences/Material chemistry, [SPI.MAT] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2016

6. Atom-scale compositional distribution in InAlAsSb-based triple junction solar cells by atom probe tomography

Author

Maria Gonzalez, F J Delgado, T. Philippe, Jesús Hernández-Saz, J. Abell, Sébastien Duguay, Sergio I. Molina, Robert J. Walters, Miriam Herrera, University of Cadiz, Groupe de physique des matériaux (GPM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de la Matière Condensée, Centre National de la Recherche Scientifique (CNRS), Sotera Defense Solutions, Naval Research Laboratory (NRL), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), U.S. Naval Research Laboratory, and U.S. Naval Research Laboratory, Washington, D. C.

Subjects
Materials science, Bioengineering, Nanotechnology, Scale (descriptive set theory), 02 engineering and technology, Atom probe, 01 natural sciences, Molecular physics, law.invention, law, 0103 physical sciences, Atom, General Materials Science, Statistical analysis, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Mechanical Engineering, Triple junction, Direct observation, General Chemistry, 021001 nanoscience & nanotechnology, Distribution (mathematics), Mechanics of Materials, 0210 nano-technology
Abstract

The analysis by atom probe tomography (APT) of InAlAsSb layers with applications in triple junction solar cells (TJSCs) has shown the existence of In- and Sb-rich regions in the material. The composition variation found is not evident from the direct observation of the 3D atomic distribution and because of this a statistical analysis has been required. From previous analysis of these samples, it is shown that the small compositional fluctuations determined have a strong effect on the optical properties of the material and ultimately on the performance of TJSCs.

Published
2016
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