5,666 research outputs found

    A family of solutions of certain nonautonomous differential equations by series of exponential functions

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    Solution of differential equations by series of exponential function

    On solutions of differential and functional equations Final report

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    Solutions of differential and functional equation

    Study of outgassing and decomposition of space shuttle heat protection tiles, fillers and adhesive

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    The purpose of this project was to determine the chemicals desorbing from the space shuttle heat protection tiles. The original protocol for this project involved direct insertion probe mass spectrometry (DIPMS) analysis of the outgassing products from the tiles. However, this method proved unsatisfactory due to the large number of compounds desorbing from the tiles. A purge and trap technique was then employed to collect and separate the chemicals desorbing from the tiles. The maximum temperature in this analysis was 180 C which is the gas chromatograph fused silica capillary column's temperature limit. The desorption was also carried out at atmospheric pressure with helium as the purge gas. A description of the modified protocol is given. All compounds are tentatively identified

    Transient technique for measuring heat transfer coefficients on stator airfoils in a jet engine environment

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    A transient technique was used to measure heat transfer coefficients on stator airfoils in a high-temperature annular cascade at real engine conditions. The transient response of thin film thermocouples on the airfoil surface to step changes in the gas stream temperature was used to determine these coefficients. In addition, gardon gages and paired thermocouples were also utilized to measure heat flux on the airfoil pressure surface at steady state conditions. The tests were conducted at exit gas stream Reynolds numbers of one-half to 1.9 million based on true chord. The results from the transient technique show good comparison with the steady-state results in both trend and magnitude. In addition, comparison is made with the STAN5 boundary layer code and shows good comparison with the trends. However, the magnitude of the experimental data is consistently higher than the analysis

    Interaction of Aircraft Wakes From Laterally Spaced Aircraft

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    Large Eddy Simulations are used to examine wake interactions from aircraft on closely spaced parallel paths. Two sets of experiments are conducted, with the first set examining wake interactions out of ground effect (OGE) and the second set for in ground effect (IGE). The initial wake field for each aircraft represents a rolled-up wake vortex pair generated by a B-747. Parametric sets include wake interactions from aircraft pairs with lateral separations of 400, 500, 600, and 750 ft. The simulation of a wake from a single aircraft is used as baseline. The study shows that wake vortices from either a pair or a formation of B-747 s that fly with very close lateral spacing, last longer than those from an isolated B-747. For OGE, the inner vortices between the pair of aircraft, ascend, link and quickly dissipate, leaving the outer vortices to decay and descend slowly. For the IGE scenario, the inner vortices ascend and last longer, while the outer vortices decay from ground interaction at a rate similar to that expected from an isolated aircraft. Both OGE and IGE scenarios produce longer-lasting wakes for aircraft with separations less than 600 ft. The results are significant because concepts to increase airport capacity have been proposed that assume either aircraft formations and/or aircraft pairs landing on very closely spaced runways

    The role of the senate in the Kenya political system

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    Learn by Giving: Non-Profit Information for Future Senior Projects

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    This report details the processes, deliverables, and partnerships between various non-profit construction organizations to provide students with accessible information about non-profit construction companies for future senior projects. The information and deliverables of this senior project also to be found in the portal for the construction management preliminary senior project class (CM 460). One of the main goals of this senior project is to encourage students to sharpen construction skills while helping communities in need. This project consists of interviewing local, national, and international non-profit companies to compile information so students understand the different opportunities they have. The first deliverable that will be presented to future students is the PowerPoint presentation. The goal of this deliverable is to give students an initial understanding of applicable non-profit organizations and clubs they can contact who would provide engaging learning experiences for future senior projects. Next, students will hopefully be interested enough in one or two non-profit organizations that they would access the Non-Profit Company Information/Resource list to gain a deeper understanding of the project they would be leading, the costs associated, logistical challenges, and location of construction. The project deliverables will make the research non-profits of less overwhelming for students

    Study of outgassing and decomposition of Space Shuttle heat protection tiles, fillers and adhesive

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    A purge and trap technique which was employed to collect and separate the chemicals desorbing from the space shuttle heat protection tiles is described. The instrumentation included a mass spectrometer and gas chromatograph
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