1,751 research outputs found
Calculation of aerodynamic characteristics of STOL aircraft
Method predicts lift and pitching moment characteristics of STOL aircraft with externally-blown, jet-augmented wing-flap combinations using potential-flow approach which involves combination of two flow models. Method can accommodate multiple engines per wing panel and part-span flaps
Computation of aerodynamic interference between lifting surfaces and lift- and cruise-fans
Sequence of three computer programs predicts aerodynamic interference on lifting surfaces of transport-type aircraft which are equipped with lift and cruise fans; for example, high-bypass-ratio engine and wing-pylon tail configuration or fuselage-mounted lift-fan and wing-tail configuration
In-flight Evaluation of Aerodynamic Predictions of an Air-launched Space Booster
Several analytical aerodynamic design tools that were applied to the Pegasus (registered trademark) air-launched space booster were evaluated using flight measurements. The study was limited to existing codes and was conducted with limited computational resources. The flight instrumentation was constrained to have minimal impact on the primary Pegasus missions. Where appropriate, the flight measurements were compared with computational data. Aerodynamic performance and trim data from the first two flights were correlated with predictions. Local measurements in the wing and wing-body interference region were correlated with analytical data. This complex flow region includes the effect of aerothermal heating magnification caused by the presence of a corner vortex and interaction of the wing leading edge shock and fuselage boundary layer. The operation of the first two missions indicates that the aerodynamic design approach for Pegasus was adequate, and data show that acceptable margins were available. Additionally, the correlations provide insight into the capabilities of these analytical tools for more complex vehicles in which the design margins may be more stringent
Letter from Delphina E. Mendenhall to John L. Ham, February 1, 1879
Letter from Delphina E. Mendenhall to John L. Ham, February 1, 1879. Delphina wrote to John Ham as an attempt to rekindle an old friendship made during the bitterest months of the war when he was released with a few other prisoners from the Salisbury, North Carolina prison camp around the time General Sherman made his march through there.Due to the state of affairs both before and during the war she and her husband were one of the few slave owners that attempted to emancipate their slaves before the war, and she mentioned that of those former slaves several went on to become very successful. She also relates the state of affairs at her household since that time during the war and some of her sad misfortunes, yet she remarked how fortunate she was to help him and the other prisoners.
Taken from the Paul W. Bean Collection, Box no. 279, f.63https://digitalcommons.library.umaine.edu/paul_bean_papers/1053/thumbnail.jp
Calculation of the longitudinal aerodynamic characteristics of STOL aircraft with externally-blown jet-augmented flaps
A theoretical investigation was made to develop methods for predicting the longitudinal aerodynamic characteristics of externally-blown, jet-augmented wing-flap combinations. A potential flow analysis was used to develop two models: a wing-flap lifting surface model and a high-bypass-ratio turbofan engine wake model. Use of these two models in sequence provides for calculation of the wing-flap load distribution including the influence of the engine wake. The method can accommodate multiple engines per wing panel and part-span flaps but is limited to the case where the flow and geometry of the configuration are symmetric about a vertical plane containing the wing root chord. Comparisons of predicted and measured lift and pitching moment on unswept and swept wings with one and two engines per panel and with various flap deflection angles indicate satisfactory prediction of lift and moment for flap deflections up to 30 to 40 degrees. At higher flap angles with and without power, the method begins to overpredict lift, due probably to the appearance of flow separation on the flaps
DNA-Protein Interactions in High Definition
An elegant, genome-wide approach to define the precise DNA sequences bound by transcription factors has been developed by Rhee and Pugh
Vacuum switching experiments at California Institute of Technology
Successful experiments in switching or breaking a circuit in a high vacuum have been made at the California Institute of Technology. This paper is a report on three sets of these experiments which extended over a period of three years. The conclusions drawn from the experiments may be summed up in the statement that vacuum breakers of laboratory type have been successful in breaking circuits and offer a possible solution of the circuit-breaker problem. The results show that switching in vacuum affords the advantages of no pitting of contacts, quick break, the arc always going out on the first half cycle, small voltage rise across the switch, and small distance of travel necessary for the switch blades. Making the vacuum switch practical calls for a solution of the problem of making commercial apparatus with vacuum-tight joints, and the elimination of the use of liquid air with the vacuum pump
Abstracting GIS Layers from Hyperspectral Imagery
The spectral-spatial relationship of materials in a hyperspectral image cube is exploited to partially automate the creation of Geographic Information System (GIS) layers. The topological neighborhood preservation property of the Self Organizing Map (SOM) is clustered into six (partially overlapping) neighborhoods that are mapped into the image domain to locate in-scene structures of similar material type. GIS layers are abstracted through spatial logical and morphological operations on the six image domain material maps and a novel road finding algorithm connects road segments under significant tree-occlusion resulting in a contiguous road network. It is assumed that specific knowledge of the scene (e.g. endmember spectra) is not available. The results are eight separate high-quality GIS layers (Vegetation, Trees, Fields, Buildings, Major Buildings, Roadways, and Parking Areas) that follow the scene features of the hyperspectral image and are separately and automatically labeled. The material maps resulting from clustering the SOM have an 84.3% average accuracy, which increases to 93.9% after spatial processing into GIS layers
[Accepted Manuscript] Nurses’ perceptions of universal health coverage and its implications for the Kenyan health sector
Universal health coverage, comprehensive access to affordable and quality health services, is a key component of the newly adopted 2015 Sustainable Development Goals. Prior to the UN resolution, several countries began incorporating elements of universal health coverage into their domestic policy arenas. In 2013, the newly elected President of Kenya announced initiatives aimed at moving towards universal health coverage, which have proven to be controversial. Little is known about how frontline workers, increasingly politically active and responsible for executing these mandates, view these changes. To understand more about how actors make sense of universal health coverage policies, we conducted an interpretive policy analysis using well-established methods from critical policy studies. This study utilized in-depth semi-structured interviews from a cross section of 60 nurses in three health facilities (public and private) in Kenya. Nurses were found to be largely unfamiliar with universal health coverage and interpreted it in myriad ways. One policy in particular, free maternal health care, was interpreted positively in theory and negatively in practice. Nurses often relied on symbolic language to express powerlessness in the wake of significant health systems reform. Study participants linked many of these frustrations to disorganization in the health sector as well as the changing political landscape in Kenya. These interpretations provide insight into charged policy positions held by frontline workers that threaten to interrupt service delivery and undermine the movement towards universal health coverage in Kenya
- …