7,073 research outputs found

    Further laboratory studies of the roughness and suspended load of alluvial streams

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    A laboratory study was made to determine the variation with depth and velocity of the hydraulic and sediment transport characteristics of a constant-discharge flow. Eight experimental runs were performed in a 60-foot long, 33.5-inch wide recirculating laboratory flume. The unit discharge for all runs was 0.50 cfs per ft. and the velocity was varied from 0.91 to 2.21 fps, corresponding to a change in depth from 0.550 to 0.228 ft. The bed sand used for these experiments had a geometric mean sieve diameter of 0.142 mm and a geometric standard deviation of 1.38. As the velocity was increased, the bed form changed from a dune-covered configuration to a flat bed, with sand waves occurring at intermediate velocities. It was found that for the unit discharge and bed sand used in this investigation, two different velocities and sediment transport rates are possible for a given slope, or a given bed shear velocity; however, this multiplicity is possible only in the range of slope and shear velocity where major changes in the bed configuration occur since it is a result of large variations in the bed roughness. Therefore the slope or shear velocity cannot logically be used as an independent variable since neither of these quantities uniquely determines the velocity or transport rate. However, if the velocity is used as the independent variable for a constant-discharge flow, the slope, shear velocity, and friction factor are all uniquely determined. The sediment transport rate was found to be a single-valued, uniformly increasing function of velocity, and it can therefore be used in place of the velocity as the independent variable. A comparison of data from this investigation with data from previous investigations which used the same sand showed that even a small decrease in the amount of fine material in the bed sand can have a significant effect on the transport rate. However, even relatively large changes in the standard deviation of the bed material have a small effect on the friction factor

    Field Guide to Coastal Environmental Geology of Rhode Island\u27s Barrier Beach Coastline

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    Guidebook to geologic field studies in Rhode Island and adjacent areas: The 73rd annual meeting of the New England Intercollegiate Geological Conference, October 16-18, 1981: Trip B-

    A summary of the forebody high-angle-of-attack aerodynamics research on the F-18 and the X-29A aircraft

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    High-angle-of-attack aerodynamic studies have been conducted on both the F18 High Alpha Research Vehicle (HARV) and the X-29A aircraft. Data obtained include on- and off-surface flow visualization and static pressure measurements on the forebody. Comparisons of similar results are made between the two aircraft where possible. The forebody shapes of the two aircraft are different and the X-29A forebody flow is affected by the addition of nose strakes and a flight test noseboom. The forebody flow field of the F-18 HARV is fairly symmetric at zero sideslip and has distinct, well-defined vortices. The X-29A forebody vortices are more diffuse and are sometimes asymmetric at zero sideslip. These asymmetries correlate with observed zero-sideslip aircraft yawing moments

    Molecular mechanisms of retinoid actions in skin

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154473/1/fsb2010009001.pd

    Prayer and personal happiness : a study among secondary school students in Australia

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    In order to examine the association between prayer and happiness, a sample of 1,002 students, ranging in age from 12- to 18-years, attending ten non-government secondary schools in Victoria, Australia, completed three measures: the Oxford Happiness Inventory, the short form of the Junior Eysenck Personality Questionnaire Revised, and a single-item measure of prayer affect assessed on a five-point scale. The data demonstrated a significant positive correlation between prayer affect and happiness after taking into account individual differences in sex, age and personality

    The Logarithmic Triviality of Compact QED Coupled to a Four Fermi Interaction

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    This is the completion of an exploratory study of Compact lattice Quantum Electrodynamics with a weak four-fermi interaction and four species of massless fermions. In this formulation of Quantum Electrodynamics massless fermions can be simulated directly and Finite Size Scaling analyses can be performed at the theory's chiral symmetry breaking critical point. High statistics simulations on lattices ranging from 848^4 to 24424^4 yield the equation of state, critical indices, scaling functions and cumulants. The measurements are well fit with the orthodox hypothesis that the theory is logarithmically trivial and its continuum limit suffers from Landau's zero charge problem.Comment: 27 pages, 15 figues and 10 table

    Real-time manhattan world rotation estimation in 3D

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    Drift of the rotation estimate is a well known problem in visual odometry systems as it is the main source of positioning inaccuracy. We propose three novel algorithms to estimate the full 3D rotation to the surrounding Manhattan World (MW) in as short as 20 ms using surface-normals derived from the depth channel of a RGB-D camera. Importantly, this rotation estimate acts as a structure compass which can be used to estimate the bias of an odometry system, such as an inertial measurement unit (IMU), and thus remove its angular drift. We evaluate the run-time as well as the accuracy of the proposed algorithms on groundtruth data. They achieve zerodrift rotation estimation with RMSEs below 3.4° by themselves and below 2.8° when integrated with an IMU in a standard extended Kalman filter (EKF). Additional qualitative results show the accuracy in a large scale indoor environment as well as the ability to handle fast motion. Selected segmentations of scenes from the NYU depth dataset demonstrate the robustness of the inference algorithms to clutter and hint at the usefulness of the segmentation for further processing.United States. Office of Naval Research. Multidisciplinary University Research Initiative6 (Awards N00014-11-1-0688 and N00014-10-1-0936)National Science Foundation (U.S.) (Award IIS-1318392

    Spiritual well-being and psychological type : a study among visitors to a medieval cathedral in Wales

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    This study explores the theoretical and empirical connections between spiritual well-being and psychological type by drawing on Fisher's model of spiritual well-being as assessed by the Spiritual Health And Life-Orientation Measure and Francis' classification of psychological type as generated by the Francis Psychological Type Scales. Data provided by 2339 visitors to St David's Cathedral in rural west Wales demonstrated that, when the four components of psychological type were considered independently, higher levels of spiritual well-being were associated with extraversion rather than introversion, with intuition rather than sensing, with feeling rather than thinking and with perceiving rather than judging. Further examination of these data suggested that the judging process (distinguishing between the feeling function and the thinking function) was of greatest importance in shaping individual differences in spiritual health

    Improving Patient Decision-Making in Health Care

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    Outlines regional variations within Minnesota in rates of patients with similar conditions receiving elective surgery, the concept of shared decision making, treatment choices for eight conditions, and steps for ensuring patients make informed decisions
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