694 research outputs found

    Full-coverage film cooling: 3-dimensional measurements of turbulence structure and prediction of recovery region hydrodynamics

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    Hydrodynamic measurements were made with a triaxial hot-wire in the full-coverage region and the recovery region following an array of injection holes inclined downstream, at 30 degrees to the surface. The data were taken under isothermal conditions at ambient temperature and pressure for two blowing ratios: M = 0.9 and M = 0.4. Profiles of the three main velocity components and the six Reynolds stresses were obtained at several spanwise positions at each of the five locations down the test plate. A one-equation model of turbulence (using turbulent kinetic energy with an algebraic mixing length) was used in a two-dimensional computer program to predict the mean velocity and turbulent kinetic energy profiles in the recovery region. A new real-time hotwire scheme was developed to make measurements in the three-dimensional turbulent boundary layer over the full-coverage surface

    Monitoring wild animal communities with arrays of motion sensitive camera traps

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    Studying animal movement and distribution is of critical importance to addressing environmental challenges including invasive species, infectious diseases, climate and land-use change. Motion sensitive camera traps offer a visual sensor to record the presence of a broad range of species providing location -specific information on movement and behavior. Modern digital camera traps that record video present new analytical opportunities, but also new data management challenges. This paper describes our experience with a terrestrial animal monitoring system at Barro Colorado Island, Panama. Our camera network captured the spatio-temporal dynamics of terrestrial bird and mammal activity at the site - data relevant to immediate science questions, and long-term conservation issues. We believe that the experience gained and lessons learned during our year long deployment and testing of the camera traps as well as the developed solutions are applicable to broader sensor network applications and are valuable for the advancement of the sensor network research. We suggest that the continued development of these hardware, software, and analytical tools, in concert, offer an exciting sensor-network solution to monitoring of animal populations which could realistically scale over larger areas and time spans

    WiseEye: next generation expandable and programmable camera trap platform for wildlife research

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    Funding: The work was supported by the RCUK Digital Economy programme to the dot.rural Digital Economy Hub; award reference: EP/G066051/1. The work of S. Newey and RJI was part funded by the Scottish Government's Rural and Environment Science and Analytical Services (RESAS). Details published as an Open Source Toolkit, PLOS Journals at: http://dx.doi.org/10.1371/journal.pone.0169758Peer reviewedPublisher PD

    The impact of members of the Society of University Surgeons on the scholarship of American surgery

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    Background A core objective of the Society of University Surgeons (SUS) is research focused: to “advance the art and science of surgery through original investigation.” This study sought to determine the current impact of the SUS on academic surgical productivity. Methods Individual faculty data for numbers of publications, citations, and National Institute of Health (NIH) funding history were collected for 4,015 surgical faculty at the top 55 NIH-funded departments of surgery using SCOPUS and the NIH Research Portfolio Online Reporting Tools. SUS membership was determined from membership registry data. Results Overall, 502 surgical faculty (12.5%) were SUS members with 92.7% holding positions of associate or full professor (versus 59% of nonmembers). Median publications (P) and citations (C) among SUS members were P: 112, C: 2,460 versus P: 29, C: 467 for nonmembers (P < .001). Academic productivity was considerably higher by rank for SUS members than for nonmembers: associate professors (P: 61 vs 36, C: 1,199 vs 591, P < .001) and full professors (P: 141 vs 81, C: 3,537 vs 1,856, P < .001). Among full professors, SUS members had much higher rates of NIH funding than did nonmembers (52.6% vs 26%, P < .05) and specifically for R01, P01, and U01 awards (37% vs 17.7%, P < .01). SUS members were 2 times more likely to serve in divisional leadership or chair positions (23.5% vs 10.2%, P < .05). Conclusion SUS society members are a highly productive academic group. These data support the premise that the SUS is meeting its research mission and identify its members as very academically productive contributors to research and scholarship in American surgery and medicine

    Assessment of overall heat transfer coefficient models to predict the performance of laboratory-scale jacketed batch reactors

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    Heat transfer models for agitated, jacketed, laboratory-scale batch reactors are required to predict process temperature profiles with great accuracy for tasks associated with chemical process development such as batch crystallization and chemical reaction kinetics modeling. The standard approach uses a reduced model which assumes the system can be adequately represented by a single overall heat transfer coefficient which is independent of time; however, the performance of reduced models for predicting the evolution of process temperature is rarely discussed. Laboratory scale (0.5 and 5 L) experiments were conducted using a Huber thermoregulator to deliver a thermal fluid at constant flow to a heat transfer jacket. It is demonstrated that the relative specific heat contribution of the reactor and inserts represent an increasing obstacle for these transient models with decreasing scale. However, a series of experiments implied that thermal losses were the limiting factor in the performance of a single coefficient reduced model at laboratory-scale. A diabatic model is presented which accounts for both thermal losses and the thermal inertia of the reactor vessel and inserts by incorporating a second coefficient and a modified heat capacity term. The mean absolute error in predicted process temperature was thereby reduced by a factor of 8, from 2.4 to 0.3 K, over a 150 min experiment

    Numerical Investigation on Charring Ablator Geometric Effects: Study of Stardust Sample Return Capsule Heat Shield

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    Sample geometry is very influential in small charring ablative articles where 1D assumption might not be accurate. In heat shield design, 1D is often assumed since the nose radius is much larger than the thickness of charring. Whether the 1D assumption is valid for the heat shield is unknown. Therefore, the geometric effects of Stardust sample return capsule heat shield are numerically studied using a material response program. The developed computer program models material charring, conductive heat transfer, surface energy balance, pyrolysis gas transport and orthotropic material properties in 3D Cartesian coordinates. Simulation results show that the centerline temperatures predicted by 3D model are quite close to 1D model at the surface, but not the case inside the material. The pyrolysis surface gas blowing behaviors are quite similar but differences are observed at later time. Orthotropic model predicted a very different heat shield response to both the isotropic model and the 1D model

    An empirical evaluation of camera trap study design: How many, how long and when?

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    Abstract Camera traps deployed in grids or stratified random designs are a well‐established survey tool for wildlife but there has been little evaluation of study design parameters. We used an empirical subsampling approach involving 2,225 camera deployments run at 41 study areas around the world to evaluate three aspects of camera trap study design (number of sites, duration and season of sampling) and their influence on the estimation of three ecological metrics (species richness, occupancy and detection rate) for mammals. We found that 25–35 camera sites were needed for precise estimates of species richness, depending on scale of the study. The precision of species‐level estimates of occupancy (ψ) was highly sensitive to occupancy level, with 0.75) species, but more than 150 camera sites likely needed for rare (ψ < 0.25) species. Species detection rates were more difficult to estimate precisely at the grid level due to spatial heterogeneity, presumably driven by unaccounted habitat variability factors within the study area. Running a camera at a site for 2 weeks was most efficient for detecting new species, but 3–4 weeks were needed for precise estimates of local detection rate, with no gains in precision observed after 1 month. Metrics for all mammal communities were sensitive to seasonality, with 37%–50% of the species at the sites we examined fluctuating significantly in their occupancy or detection rates over the year. This effect was more pronounced in temperate sites, where seasonally sensitive species varied in relative abundance by an average factor of 4–5, and some species were completely absent in one season due to hibernation or migration. We recommend the following guidelines to efficiently obtain precise estimates of species richness, occupancy and detection rates with camera trap arrays: run each camera for 3–5 weeks across 40–60 sites per array. We recommend comparisons of detection rates be model based and include local covariates to help account for small‐scale variation. Furthermore, comparisons across study areas or times must account for seasonality, which could have strong impacts on mammal communities in both tropical and temperate sites

    Confirmation of low genetic diversity and multiple breeding females in a social group of Eurasian badgers from microsatellite and field data

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    The Eurasian badger ( Meles meles ) is a facultatively social carnivore that shows only rudimentary co-operative behaviour and a poorly defined social hierarchy. Behavioural evidence and limited genetic data have suggested that more than one female may breed in a social group. We combine pregnancy detection by ultrasound and microsatellite locus scores from a well-studied badger population from Wytham Woods, Oxfordshire, UK, to demonstrate that multiple females reproduce within a social group. We found that at least three of seven potential mothers reproduced in a group that contained 11 reproductive age females and nine offspring. Twelve primers showed variability across the species range and only five of these were variable in Wytham. The microsatellites showed a reduced repeat number, a significantly higher number of nonperfect repeats, and moderate heterozygosity levels in Wytham. The high frequency of imperfect repeats and demographic phenomena might be responsible for the reduced levels of variability observed in the badger
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