249 research outputs found

    Experimental verification of a new laminar airfoil: A project for the graduate program in aeronautics

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    Two reports on student activities to determine the properties of a new laminar airfoil which were delivered at a conference on soaring technology are presented. The papers discuss a wind tunnel investigation and analysis of the SM701 airfoil and verification of the SM701 airfoil aerodynamic charcteristics utilizing theoretical techniques. The papers are based on a combination of analytical design, hands-on model fabrication, wind tunnel calibration and testing, data acquisition and analysis, and comparison of test results and theory

    A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals

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    The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described

    Hydrologic models for land-atmosphere retrospective studies of the use of LANDSAT and AVHRR data

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    The use of a Geographic Information System (GIS) and LANDSAT analysis in conjunction with the Simulator for Water Resources on a Rural Basin (SWRRB) hydrologic model to examine the water balance on the Little Washita River basin is discussed. LANDSAT analysis was used to divide the basin into eight non-contiguous land covers or subareas: rangeland, grazed range, winter wheat, alfalfa/pasture, bare soil, water, woodland, and impervious land (roads, quarry). The use of a geographic information system allowed for the calculation of SWRRB model parameters in each subarea. Four data sets were constructed in order to compare SWRRB estimates of hydrologic processes using two methods of maximum LAI and two methods of watershed subdivision. Maximum LAI was determined from a continental scale map, which provided a value of 4.5 for the entire basin, and from its association with the type of land-cover (eight values). The two methods of watershed subdivision were determined according to drainage subbasin (four) and the eight land-covers. These data sets were used with the SWRRB model to obtain daily hydrologic estimates for 1985. The results of the one year analysis lead to the conclusion that the greater homogeneity of a land-cover subdivision provides better water yield estimates than those based on a drainage properties subdivision

    The relationship between single-sex and co-educational environments on socioemotional development

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    There have been many debates over the advantages and disadvantages of single-sex education with regards to socioemotional development. Although some research shows that girls are often neglected in the classroom when boys are present, other research states that single-sex education may not be as beneficial as thought. The purpose of this study was to examine the discrepancies between previous research on single-sex and co-educational environments in relation to socioemotional development. Specifically, we investigated the differences in perceived competence, self-esteem, locus of control, and perceived social support. Within these areas of socioemotional development, we expect differences to exist based on educational environment. However, we are reluctant to postulate which educational environment will yield the higher scores in each area since conflicting research is present

    A framework for detecting unnecessary industrial data in ETL processes

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    Extract transform and load (ETL) is a critical process used by industrial organisations to shift data from one database to another, such as from an operational system to a data warehouse. With the increasing amount of data stored by industrial organisations, some ETL processes can take in excess of 12 hours to complete; this can leave decision makers stranded while they wait for the data needed to support their decisions. After designing the ETL processes, inevitably data requirements can change, and much of the data that goes through the ETL process may not ever be used or needed. This paper therefore proposes a framework for dynamically detecting and predicting unnecessary data and preventing it from slowing down ETL processes - either by removing it entirely or deprioritizing it. Other advantages of the framework include being able to prioritise data cleansing tasks and determining what data should be processed first and placed into fast access memory. We show existing example algorithms that can be used for each component of the framework, and present some initial testing results as part of our research to determine whether the framework can help to reduce ETL time.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/INDIN.2014.694555

    Theory versus experiment for the rotordynamic coefficients of annular gas seals. Part 1: Test facility and apparatus

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    A facility and apparatus are described for determining the rotordynamic coefficients and leakage characteristics of annular gas seals. The apparatus has a current top speed of 8000 cpm with a nominal seal diameter of 15.24 cmn (6 in). The air supply unit yields a seal pressure ratio of approximately 7. An external shaker is used to excite the test rotor. The capability to independently calculate all rotordynamic coefficients at a given operating condition with one excitation frequency are discussed

    Group elastic symmetries common to continuum and discrete defective crystals

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    The Lie group structure of crystals which have uniform continuous distributions of dislocations allows one to construct associated discrete structures—these are discrete subgroups of the corresponding Lie group, just as the perfect lattices of crystallography are discrete subgroups of R 3 , with addition as group operation. We consider whether or not the symmetries of these discrete subgroups extend to symmetries of (particular) ambient Lie groups. It turns out that those symmetries which correspond to automorphisms of the discrete structures do extend to (continuous) symmetries of the ambient Lie group (just as the symmetries of a perfect lattice may be embedded in ‘homogeneous elastic’ deformations). Other types of symmetry must be regarded as ‘inelastic’. We show, following Kamber and Tondeur, that the corresponding continuous automorphisms preserve the Cartan torsion, and we characterize the discrete automorphisms by a commutativity condition, (6.14), that relates (via the matrix exponential) to the dislocation density tensor. This shows that periodicity properties of corresponding energy densities are determined by the dislocation density

    A skin abscess model for teaching incision and drainage procedures

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    <p>Abstract</p> <p>Background</p> <p>Skin and soft tissue infections are increasingly prevalent clinical problems, and it is important for health care practitioners to be well trained in how to treat skin abscesses. A realistic model of abscess incision and drainage will allow trainees to learn and practice this basic physician procedure.</p> <p>Methods</p> <p>We developed a realistic model of skin abscess formation to demonstrate the technique of incision and drainage for educational purposes. The creation of this model is described in detail in this report.</p> <p>Results</p> <p>This model has been successfully used to develop and disseminate a multimedia video production for teaching this medical procedure. Clinical faculty and resident physicians find this model to be a realistic method for demonstrating abscess incision and drainage.</p> <p>Conclusion</p> <p>This manuscript provides a detailed description of our model of abscess incision and drainage for medical education. Clinical educators can incorporate this model into skills labs or demonstrations for teaching this basic procedure.</p

    An investigation of the chemistry of ship emission plumes during ITCT 2002

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    A ship emission plume experiment was conducted about 100 km off the California coast during the NOAA Intercontinental Transport and Chemical Transformation (ITCT) 2K2 airborne field campaign. Measurements of chemical species were made from the NOAA WP-3D aircraft in eight consecutive transects of a ship plume around midday during 2.5 hours of flight. The measured species include NOx, HNO3, peroxyacetylnitrate (PAN), SO2, H2SO4, O3, CO, CO2, nonmethane hydrocarbons (NMHC), and particle number and size distributions. Observations demonstrate a NOx lifetime of ∼1.8 hours inside the ship plume compared to ∼6.5 hours (at noontime) in the moderately polluted background marine boundary layer of the experiment. This confirms the earlier hypothesis of highly enhanced in-plume NOx destruction. Consequently, one would expect the impact of ship emissions is much less severe than those predicted by global models that do not include rapid NOx destruction. Photochemical model calculations suggest that more than 80% of the NOx loss was due to the NO2 + OH reaction; the remainder was by PAN formation. The model underestimated in-plume NOx loss rate by about 30%. In addition, a comparison of measured to predicted H2SO4 in the plumes suggests that the photochemical model predicts OH variability reasonably well but may underestimate actual values. Predictions of in-plume O3 production agree well with the observations, suggesting that model-predicted peroxy radical (HO2 + RO2) levels are reasonable. The model estimated ozone production efficiency ranges from 6 to 30. The largest model bias was seen in the comparison with measured HNO3. The model overestimated in-plume HNO3 by about a factor of 6. This is most likely caused by underestimated HNO3 sinks possibly involving particle scavenging. However, limited data availability precluded a conclusive test of this possible loss process. Copyright 2005 by the American Geophysical Union
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