1,562 research outputs found

    Properties of asphalt mixtures containing RAP

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    Recycling has become a necessity in today\u27s world as natural resources, quality materials, and landfills have become less accessible. This project looks at how varying percentages of Reclaimed Asphalt Pavement (RAP) affect the volumetric and mechanistic properties of an asphalt concrete mixture. Specimens were made with 0%, 15%, 25%, 40%, and 100% RAP, with 0% RAP used as the baseline condition. Based on statistical analysis, the 0% RAP specimens had significantly lower stiffness than the 40% RAP specimens and significantly lower strength than the 15%, 25% and 40% RAP specimens. The high air void content of the 100% RAP specimens made them incomparable with the other specimens. The voids in mineral aggregate and voids filled by asphalt showed an increasing trend as the RAP content was increased. Compaction type was also studied in this project. Specimens that were laboratory compacted were statistically stiffer and stronger than field compacted specimens

    Marine Benthic Habitat Mapping of Muir Inlet, Glacier Bay National Park and Preserve, Alaska With an Evaluation of the Coastal and Marine Ecological Classification Standard III

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    Seafloor geology and potential benthic habitats were mapped in Muir Inlet, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, ground-truth information, and geological interpretations. Muir Inlet is a recently deglaciated fjord that is under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the Coastal and Marine Ecological Classification Standard (CMECS) recently developed by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Substrates within Muir Inlet are dominated by mud, derived from the high glacial debris flux. Water-column characteristics are derived from a combination of conductivity temperature depth (CTD) measurements and circulation-model results. We also present modern glaciomarine sediment accumulation data from quantitative differential bathymetry. These data show Muir Inlet is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The accompanying maps represent the first publicly available high-resolution bathymetric surveys of Muir Inlet. The results of these analyses serve as a test of the CMECS and as a baseline for continued mapping and correlations among seafloor substrate, benthic habitats, and glaciomarine processes

    BIOH 202N.00: Human Anatomy and Physiology I - Laboratory

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    Writing themselves in 3: the third national study on the sexual health and wellbeing of same sex attracted and gender questioning young people

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    Executive Summary Introduction This is the third of the Writing Themselves In national reports which have been conducted six years apart since 1998. In 2010, a total of 3134 same sex attracted and gender questioning (SSAGQ) young people participated in Writing Themselves In 3 (WTi3), almost double the number in 2004 and more than four times that of 1998. The participants, who were aged between 14 and 21 years, came from all states and territories of Australia, from remote (2%), rural (18%) and urban (67%) areas and from a range of culturally and linguistically diverse (CALD) backgrounds. There were more young women (57%) than young men (41%) and a smaller group (3%) who were gender questioning (GQ). Sexual feelings In 2010, the complex interaction of sexual attraction, identity and behaviour was even more evident than in previous studies. Most young men were exclusively same sex attracted but half of the young women were attracted to both sexes and less than one third exclusively to the same sex. More than a third of young people realized their sexual difference before puberty and there were few gender differences in age of first realization. More young people felt positive about their same sex attraction than in 2004. As in 2004, young people who felt bad about their sexuality used homophobic beliefs to describe their reasons whereas those who felt good used resistant, affirming explanations. Sexual identity Most young men identified as gay/homosexual. Young women were more likely to identify as bisexual. Young women chose a greater range of identity terms to describe their sexuality

    Countermovement jump variables not tensiomyography can distinguish between sprint and endurance focused track cyclists

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    This study investigated the reliability and discriminative ability of tensiomyography and countermovement jump variables as measures of a muscles contractile properties in a cohort of elite endurance and sprint track cyclists. Tensiomyography was performed on the vastus lateralis (VL) and rectus femoris (RF) muscles in sprint track cyclists (N = 8) and endurance track cyclists (N = 8). Additionally, the participants completed a countermovement jump on a force plate. Tensiomyography measurements obtained from the RF displayed greater reliability (ICC = 0.879–0.997) than VL (ICC = 0.746–0.970). Radial muscle belly displacement (Dm), contraction time (Tc) and delay time (Td) demonstrated the most reliable TMG measurements. Only two variables displayed acceptable coefficient of variation (RF Td = 8.89, VL Td = 6.88), other variables presented as unacceptable. The TMG variables were unable to discriminate between endurance and sprint track cyclists whilst the CMJ variables could. Due to the high variability in measurements and its inability to distinguish between sprint and endurance based track cyclists TMG should be used cautiously in this athlete population and if available the CMJ is a more appropriate assessment of leg muscle function. © 2022 Institute of Sport. All rights reserved

    GPS Navigation for the Magnetospheric Multi-Scale Mission

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    In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter utilizing a TDMA schedule to distribute a science quality message to all constellation members every ten seconds. Additionally the system generates one-way range measurements between formation members which is used as input to the Kalman filter. In preparation for the MMS Preliminary Design Review (PDR), the Navigator was required to pass a series of Technology Readiness Level (TRL) tests to earn the necessary TRL-6 classification. The TRL-6 level is achieved by demonstrating a prototype unit in a relevant end-to-end environment. The IRAS unit was able to meet all requirements during the testing phase, and has thus been TRL-6 qualifie

    Predicted Performance of an X-Ray Navigation System for Future Deep Space and Lunar Missions

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    In November 2017, the NASA Goddard Space Flight Center (GSFC) Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) experiment successfully demonstrated the feasibility of X-ray Pulsar Navigation (XNAV) as part of the Neutron Star Interior Composition Explorer (NICER) mission, which is an X-ray Astrophysics Mission of Opportunity currently operating onboard the International Space Station (ISS). XNAV provides a GPS-like absolute autonomous navigation and timing capability available anywhere in the Solar System and beyond. While the most significant benefits of XNAV are expected to come in support of very deep-space missions, the absolute autonomous navigation and timing capability also has utility for inner Solar System missions where increased autonomy or backup navigation and timing services are required, e.g., address loss of communication scenarios.The NASA commitment to develop a Gateway to support exploration of the Moon and eventually Mars, as well as current and future robotic missions such as James Webb Space Telescope (JWST), New Horizons, and much more, certainly will tax the existing ground based infrastructure in terms of availability. There- fore, an extended look at the feasibility and potential performance of XNAV for comparable missions is warranted. In this paper, we briefly review the XNAV concept and present case studies of its utility and performance for a Gateway orbit, Sun-Earth libration orbit, and a deep space transit trajectory

    Introducing a Clinical Practice Guideline Using Early CT in the Diagnosis of Scaphoid and Other Fractures

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    Objective: We developed and implemented clinical practice guideline (CPG) using computerized tomography (CT) as the initial imaging method in the emergency department management of scaphoid fractures. We hypothesized that this CPG would decrease unnecessary immobilization and lead to earlier return to work.Methods: This observational study evaluated implementation of our CPG, which incorporated early wrist CT in patients with “clinical scaphoid fracture”: a mechanism of injury consistent with scaphoid fracture, anatomical snuff box tenderness, and normal initial plain x-rays. Outcome measures were the final diagnosis as determined by orthopaedic review of the clinical and imaging data. Patient outcomes included time to return to work and patient satisfaction as determined by telephone interview at ten days.Results: Eighty patients completed the study protocol in a regional emergency department.In this patient population CT detected 28 fractures in 25 patients, including six scaphoid fractures, five triquetral fractures, four radius fractures, and 13 other related fractures. Fifty-three patients had normal CT. Eight of these patients had significant ongoing pain at follow up and had an MRI, with only two bone bruises identified. The patients with normal CTs avoided prolonged immobilization (mean time in plaster 2.7 days) and had no or minimal time off work (mean 1.6 days). Patient satisfaction was an average 4.2/5.Conclusion: This CPG resulted in rapid and accurate management of patients with suspected occult scaphoid injury, minimized unnecessary immobilization and was acceptable to patients.[WestJEM. 2009;10(4):227-232.
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