5,738 research outputs found
A CCD image transducer and processor suitable for space flight
A satellite borne extreme ultraviolet solar telescope makes use of CCD area arrays for both image readout and onboard data processing. The instrument is designed to view the inner solar corona in the wavelength band 170 - 630 A, and the output video stream may be selected by ground command to present the coronal scene, or the time-rate-of-change of the scene. Details of the CCD application to onboard image processing are described, and a discussion of the processor's potential for telemetry bandwidth compression is included. Optical coupling methods, data storage requirements, spatial and temporal resolution, and nonsymmetry of resolution (pitch) in the CCD are discussed
Compact 20-kiloampere pulse-forming-network capacitor bank
Bank uses commercially available high-energy-density capacitors for energy storage and silicon-controlled rectifiers for switching. Low voltage design employing solid-state switching is utilized in lieu of conventional gas discharge switching
Correlation of transient spectra with performance in coaxial plasma guns
Two channel transient voltage digitizer for correlation of transient spectra with performance in coaxial, argon plasma gun
Forward acoustic performance of a model turbofan designed for a high specific flow (QF-14)
Forward noise and overall aerodynamic performance are presented for a high-tip-speed fan having an exceptionally high average axial Mach number at the rotor inlet. This high Mach number is intended to attenuate forward noise at both the design-speed takeoff point, and at the unconventional low-pressure-ratio, design-speed approach point. As speed was increased near design, all forward noise components were reduced, and rear noise in the discharge duct was increased, indicating that the high Mach number flow at the rotor face is attenuating forward noise at takeoff. The fan at takeoff is some 5.5 to 11 dB quieter than several reference fans. Data at the point closest to approach indicated tentatively that the design-speed approach mode was 3 dB quieter than the conventional mode
Prudence and Persistence: Personality in Student Retention
Student retention is a concern for many higher education institutions and there are many techniques that can be used to increase student retention. Previous research has used student personality data to customize interventions aimed at increasing student success and retention. In this study, prudence levels of incoming students was assessed, and a customized email intervention was designed and administered to students with students having low prudence levels. A variety of outcome measures were used to assess the usefulness of the intervention, including GPA, academic and behavioral citations, and use of campus resources. Results indicate that prudence levels are positively related to GPA and course completion rates. Similarly, the customized email intervention was positively related to GPA, course completion rates, and negatively related to university-issued behavioral citations. The results indicate that prudence levels and customized interventions may be effective for increasing student retention. The meaning and applications of these findings are discussed, and suggestions for future research are outlined
Pavement Condition Index and Cost of Ownership Analysis on Preventative Maintenance Projects in Kentucky
The Commonwealth of Kentucky has seen increasing use over time of preventative maintenance treatments on its asphalt pavements. Performance of two of the most prevalent treatments employed by the Kentucky Transportation Cabinet (KYTC) – Thin Asphalt Overlay (Thinlay) and Microsurfacing – had yet to be examined in-depth through condition surveys. This thesis describes the data collection process to find the Pavement Condition Index (PCI) of each preventative maintenance site in Kentucky from the last 10 years. With PCI from each site, deterioration curves were generated for each treatment – providing the estimated life extension benefit of each. The analysis then converted life extension to life cycle costs to ultimately determine which product was more cost effective. Cost effectiveness would be the definitive metric in determining which product should be used by KYTC. It is hoped that this thesis can begin to quantitatively and statistically answer the question of how to best approach asphalt maintenance projects in Kentucky
On the General Analytical Solution of the Kinematic Cosserat Equations
Based on a Lie symmetry analysis, we construct a closed form solution to the
kinematic part of the (partial differential) Cosserat equations describing the
mechanical behavior of elastic rods. The solution depends on two arbitrary
analytical vector functions and is analytical everywhere except a certain
domain of the independent variables in which one of the arbitrary vector
functions satisfies a simple explicitly given algebraic relation. As our main
theoretical result, in addition to the construction of the solution, we proof
its generality. Based on this observation, a hybrid semi-analytical solver for
highly viscous two-way coupled fluid-rod problems is developed which allows for
the interactive high-fidelity simulations of flagellated microswimmers as a
result of a substantial reduction of the numerical stiffness.Comment: 14 pages, 3 figure
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