3,545 research outputs found

    A novel bifunctional oxygen GDE for alkaline secondary batteries

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    AbstractThis paper describes a novel procedure for the fabrication of a gas diffusion electrode (GDE) suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated by pre-forming a PTFE-bonded nickel powder layer on a nickel foam substrate followed by deposition of NiCo2O4 spinel electrocatalyst by dip coating in a nitrate solution and thermal decomposition. The carbon-free composition avoids concerns over carbon corrosion at the potentials for oxygen evolution. The electrode shows acceptable overpotentials for both oxygen evolution and oxygen reduction at current densities up to 100mAcm−2. Stable performance during >100 successive, 1h oxygen reduction/evolution cycles at a current density of 20mAcm−2 in 8M NaOH at 333K was achieved

    Three-dimensional bottom diffraction in the North Pacific

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    Author Posting. © Acoustical Society of America, 2019. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 146(3), (2019): 1913-1922, doi:10.1121/1.5125427.A significant aspect of bottom-interaction in deep water acoustic propagation, from point sources to point receivers, is the diffraction (or scattering) of energy from discrete seafloor locations along repeatable, deterministic paths in three-dimensions. These bottom-diffracted surface-reflected (BDSR) paths were first identified on the North Pacific acoustic laboratory experiment in 2004 (NPAL04) for a diffractor located on the side of a small seamount. On the adjacent deep seafloor, ambient noise and propagation in the ocean sound channel were sufficiently quiet that the BDSRs were the dominant arrival. The ocean bottom seismometer augmentation in the North Pacific (OBSANP) experiment in June–July 2013 studied BDSRs at the NPAL04 site in more detail. BDSRs are most readily identified by the arrival time of pulses as a function of range to the receiver for a line of transmissions. The diffraction points for BDSRs occur on the relatively featureless deep seafloor as well as on the sides of small seamounts. Although the NPAL04 and OBSANP experiments had very different geometries the same diffractor location is consistent with observed arrivals in both experiments within the resolution of the analysis. On OBSANP the same location excites BDSRs for 77.5, 155, and 310 Hz transmissions.We greatly appreciate the support from Captain Curl, the officers, and crew of the R/V Melville (MV1308). The OBS data used in this research was acquired on instruments from the ocean bottom seismograph instrument pool (OBSIP) at Scripps Institution of Oceanography. Ernie Aaron (SIO) was responsible for shipboard OBS operations. The multi-beam data was processed using the MB-System (Caress and Chayes, 1996). Figure 1 was prepared using the generic mapping tool (Wessel and Smith, 1998). Feedback and reviews from an anonymous reviewer and the editorial staff of JASA are also greatly appreciated. The OBSANP experiment was funded by the ONR Ocean Acoustics Program (Code 322 OA) under Grant Nos. N00014-10-1-0987 and N00014-10-1-0510. Analysis was carried out under ONR Grant Nos. N00014-14-1-0324, N00014-16-1-2337, and N00014-17-C-7043.2020-03-3

    A novel bifunctional oxygen GDE for alkaline secondary batteries

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    This paper describes a novel procedure for the fabrication of a gas diffusion electrode (GDE) suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated by pre-forming a PTFE-bonded nickel powder layer on a nickel foam substrate followed by deposition of NiCo2O4 spinel electrocatalyst by dip coating in a nitrate solution and thermal decomposition. The carbon-free composition avoids concerns over carbon corrosion at the potentials for oxygen evolution. The electrode shows acceptable overpotentials for both oxygen evolution and oxygen reduction at current densities up to 100 mA cm−2. Stable performance during >100 successive, 1 h oxygen reduction/evolution cycles at a current density of 20 mA cm−2 in 8 M NaOH at 333 K was achieved.European Commissio

    Evaluating the Environmental Performance of the U.S. Next Generation Air Transportation System

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    The environmental impacts of several possible U.S. Next Generation Air Transportation scenarios have been quantitatively evaluated for noise, air-quality, fuel-efficiency, and CO2 impacts. Three principal findings have emerged. (1) 2025 traffic levels about 30% higher than 2006 are obtained by increasing traffic according to FAA projections while also limiting traffic at each airport using reasonable ratios of demand to capacity. NextGen operational capabilities alone enable attainment of an additional 10-15% more flights beyond that 2025 baseline level with negligible additional noise, air-quality, and fuel-efficiency impacts. (2) The addition of advanced engine and airframe technologies provides substantial additional reductions in noise and air-quality impacts, and further improves fuel efficiency. 2025 environmental goals based on projected system-wide improvement rates of about 1% per year for noise and fuel-efficiency (an air-quality goal is not yet formulated) are achieved using this new vehicle technology. (3) Overall air-transport "product", as measured by total flown distance or total payload distance, increases by about 50% relative to 2006, but total fuel consumption and CO2 production increase by only about 40% using NextGen operational capabilities. With the addition of advanced engine/airframe technologies, the increase in total fuel consumption and CO2 production can be reduced to about 30%

    Preliminary Validation of a Mobility Obstacle Course for Persons with Mobility Impairment

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    The purpose of this study was to assess the reliability and validity of a mobility obstacle course for women with mobility impairments. Participants included 72 adult women with permanent physical disabilities including arthritis, orthopedic conditions, paraplegia, and others. The 60-m course consisted of carpeted runways and turns, ramps, a doorway, a transfer, and object manipulation. Participants completed two trials, walking or wheeling through the course as quickly as possible, safely and without running. Total course time and peak heart rate data were correlated with SF-36 health survey subscales. Overall, peak heart rate was significantly (p \u3c .05) correlated with physical functioning (r = -.328), limitations due to physical functioning (r = .261), and pain (r = .296). Total course time was significantly correlated with physical functioning. These findings indicate very high reliability and preliminary evidence of validity

    Ocean Bottom Seismometer Augmentation in the North Pacific (OBSANP) - cruise report

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    The Ocean Bottom Seismometer Augmentation in the North Pacific Experiment (OBSANP, June-July, 2013, R/V Melville) addresses the coherence and depth dependence of deep-water ambient noise and signals. During the 2004 NPAL Experiment in the North Pacific Ocean, in addition to predicted ocean acoustic arrivals and deep shadow zone arrivals, we observed "deep seafloor arrivals" (DSFA) that were dominant on the seafloor Ocean Bottom Seismometer (OBS) (at about 5000m depth) but were absent or very weak on the Distributed Vertical Line Array (DVLA) (above 4250m depth). At least a subset of these arrivals correspond to bottomdiffracted surface-reflected (BDSR) paths from an out-of-plane seamount. BDSR arrivals are present throughout the water column, but at depths above the conjugate depth are obscured by ambient noise and PE predicted arrivals. On the 2004 NPAL/LOAPEX experiment BDSR paths yielded the largest amplitude seafloor arrivals for ranges from 500 to 3200km. The OBSANP experiment tests the hypothesis that BDSR paths contribute to the arrival structure on the deep seafloor even at short ranges (from near zero to 4-1/2CZ). The OBSANP cruise had three major research goals: a) identification and analysis of DSFA and BDSR arrivals occurring at short (1/2CZ) ranges in the 50 to 400Hz band, b) analysis of deep sea ambient noise in the band 0.03 to 80Hz, and c) analysis of the frequency dependence of BR and SRBR paths. On OBSANP we deployed a 32 element VLA from 12 to 1000m above the seafloor, eight short-period OBSs and four long-period OBSs and carried out a 15day transmission program using a J15-3 acoustic source.Funding was provided by the Office of Naval Research under contract #'s N00014-10-1-0987 and N00014-10-1-051

    Online cognitive-based intervention for depression: exploring possible circularity in mechanisms of change.

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    Background. This study investigates possible circularity in mechanisms of change in participants of Master Your Mood (MYM), a cognitive-based, online intervention for young adults with depressive symptoms. A previous study showed that MYM effectively reduced depression and anxiety and strengthened mastery
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