608 research outputs found

    Applying rotorcraft modelling technology to renewable energy research

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    The perceived need to reduce mankind's impact on the global climate motivates towards a future society in which a significant proportion of its energy needs will be extracted from the winds and the tides of the planet. This paper shows several examples of the application of Brown's Vorticity Transport Model, originally developed to perform simulations of helicopter aeromechanics and wake dynamics, to the analysis of the performance of renewable energy devices and their possible impact on the environment. Prediction of the loading on wind turbines introduces significant additional challenges to such a model, including the need to account fully for the effects of radial flow on blade stall. The wake-mediated aerodynamic interactions that occur within a wind farm can reduce its power output significantly, but this problem is very similar to that where the aerodynamic unsteadiness of the coupled wake of the main and tail rotors of a helicopter can result in significantly increased pilot workload. The helicopter-related problem of brownout, encountered during operations in desert conditions, has its analogue in the entrainment of sediment into the wakes of tidal turbines. In both cases it may be possible to ameliorate the influence of the rotor on its environment by careful and well-informed design. Finally, calculations of the distortion and dispersal of the exhaust plumes of a helicopter by the wake of its rotor allow insight into how wind turbines might interfere with the dispersal of pollutants from nearby industrial sites. These examples show how cross-disciplinary information transfer between the rotorcraft field and the renewable energy community is helping to develop the technologies that will be required by our future society, as well as helping to understand the environmental issues that might need to be faced as these technologies become more prevalent

    Community Memories: A Glimpse of African American Life in Frankfort, Kentucky

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    Community Memories is a fascinating look into life recalled by African Americans who consider Frankfort their home. Featuring unique oral history recollections and over two hundred candid personal photographs collected from community residents, the book provides an enlightening expression of the black experience in Kentucky’s capital. The memories focus on the elusive concept of community—that which binds together individuals in the living of everyday life. A satisfying blend of public history and local accounts, Community Memories explores the neighborhood, familial, religious, occupational, social, and educational components of the daily community experience of twentieth-century African Americans in Frankfort. Published by the Kentucky Historical Society and distributed by the University Press of Kentucky Senior Editor Winona L. Fletcher is professor emerita of theater and drama at Indiana University. Associate Editor Sheila Mason Burton is assistant director for research coordination at the Kentucky Legislative Research Commission. Associate Editor James E. Wallace is assistant director of the Kentucky Historical Society. Photographs Editor Mary E. Winter is special collections branch manager and photographs archivist at the Kentucky Historical Society. Oral History Editor Douglas A. Boyd is oral history and folklife archivist at the Kentucky Historical Society.https://uknowledge.uky.edu/upk_african_american_studies/1024/thumbnail.jp

    Relative efficacy of three approaches to mitigate Crown‑of‑Thorns Starfish outbreaks on Australia’s Great Barrier Reef

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    Population outbreaks of Crown-of-Thorns Starfish (COTS; Acanthaster spp.) are a major contributor to loss of hard coral throughout the Indo-Pacific. On Australia’s Great Barrier Reef (GBR), management interventions have evolved over four COTS outbreaks to include: (1) manual COTS control, (2) Marine Protected Area (MPA) zoning, and, (3) water quality improvement. Here we evaluate the contribution of these three approaches to managing population outbreaks of COTS to minimize coral loss. Strategic manual control at sites reduced COTS numbers, including larger, more fecund and damaging individuals. Sustained reduction in COTS densities and improvements in hard coral cover at a site were achieved through repeated control visits. MPAs influenced initial COTS densities but only marginally influenced final hard coral cover following COTS control. Water quality improvement programs have achieved only marginal reductions in river nutrient loads delivered to the GBR and the study region. This, a subsequent COTS outbreak, and declining coral cover across the region suggest their contributions are negligible. These findings support manual control as the most direct, and only effective, means of reducing COTS densities and improving hard coral cover currently available at a site. We provide recommendations for improving control program effectiveness with application to supporting reef resilience across the Indo-Pacific

    The AAMC Standardized Video Interview: Reactions and Use by Residency Programs During the 2018 Application Cycle

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    PURPOSE: To evaluate how emergency medicine (EM) residency programs perceived and used Association of American Medical Colleges (AAMC) SVI total scores and videos during the Electronic Residency Application Service (ERAS) 2018 cycle. METHOD: Study 1 (November 2017) used a program director survey to evaluate user reactions to the SVI following the first year of operational use. Study 2 (January 2018) analyzed program usage of SVI video responses using data collected through the AAMC Program Director\u27s Workstation. RESULTS: Results from the survey (125/175 programs, 71% response rate) and video usage analysis suggested programs viewed videos out of curiosity and to understand the range of SVI total scores. Programs were more likely to view videos for attendees of U.S. MD-granting medical schools and applicants with higher United States Medical Licensing Examination Step 1 scores, but there were no differences by gender or race/ethnicity. More than half of programs that did not use SVI total scores in their selection processes were unsure of how to incorporate them (36/58, 62%) and wanted additional research on utility (33/58, 57%). More than half of programs indicated being at least somewhat likely to use SVI total scores (55/97; 57%) and videos (52/99; 53%) in the future. CONCLUSIONS: Program reactions on the utility and ease of use of SVI total scores were mixed. Survey results indicate programs used the SVI cautiously in their selection processes, consistent with AAMC recommendations. Future surveys of SVI users will help the AAMC gauge improvements in user acceptance and familiarity with the SVI

    A pilot time-in-bed restriction intervention behaviorally enhances slow-wave activity in older adults

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    IntroductionIdentifying intervention methods that target sleep characteristics involved in memory processing is a priority for the field of cognitive aging. Older adults with greater sleep efficiency and non-rapid eye movement slow-wave activity (SWA) (0.5–4 Hz electroencephalographic activity) tend to exhibit better memory and cognitive abilities. Paradoxically, long total sleep times are consistently associated with poorer cognition in older adults. Thus, maximizing sleep efficiency and SWA may be a priority relative to increasing mere total sleep time. As clinical behavioral sleep treatments do not consistently enhance SWA, and propensity for SWA increases with time spent awake, we examined with a proof-of concept pilot intervention whether a greater dose of time-in-bed (TiB) restriction (75% of habitual TiB) would increase both sleep efficiency and SWA in older adults with difficulties staying asleep without impairing memory performance.MethodsParticipants were adults ages 55–80 with diary-reported sleep efficiency < 90% and wake after sleep onset (WASO) >20 min. Sleep diary, actigraphy, polysomnography (PSG), and paired associate memory acquisition and retention were assessed before and after a week-long TiB restriction intervention (n = 30). TiB was restricted to 75% of diary-reported habitual TiB. A comparison group of n = 5 participants repeated assessments while following their usual sleep schedule to obtain preliminary estimates of effect sizes associated with repeated testing.ResultsSubjective and objective sleep measures robustly improved in the TiB restriction group for sleep quality, sleep depth, sleep efficiency and WASO, at the expense of TiB and time spent in N1 and N2 sleep. As hypothesized, SWA increased robustly with TiB restriction across the 0.5–4 Hz range, as well as subjective sleep depth, subjective and objective WASO. Despite increases in sleepiness ratings, no impairments were found in memory acquisition or retention.ConclusionA TiB restriction dose equivalent to 75% of habitual TiB robustly increased sleep continuity and SWA in older adults with sleep maintenance difficulties, without impairing memory performance. These findings may inform long-term behavioral SWA enhancement interventions aimed at improving memory performance and risk for cognitive impairments
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