Engineering support for an ultraviolet imager for the ISTP mission

Design and development activities were carried out for the Ultraviolet Imager (UVI) to be flown on the Polar Spacecraft of the INternational Solar Terrestrial Physics (ISTP) Mission. The following tasks were performed: (1) design and fabrication of prototype/engineering model of the UVI imager; (2) preliminary design review; (3) vacuum ultraviolet filter design; (4) auroral energy deposition code; (5) model of LBH vehicle glow; (6) laboratory measurement program of collision cross-sections; and (7) support of ISTP meetings

Conduction Mapping for Quality Control of Laser Powder Bed Fusion Additive Manufacturing

A process was developed to identify potential defects in previous layers of Selective Laser Melting (SLM) Powder Bed Fusion (PBF) 3D printed metal parts using a mid-IR thermal camera to track infrared 3.8-4 m band emission over time as the part cooled to ambient temperature. Efforts focused on identifying anomalies in thermal conduction. To simplify the approach and reduce the need for significant computation, no attempts were made to calibrate measured intensity, extract surface temperature, apply machine learning, or compare measured cool-down behavior to computer model predictions. Raw intensity cool-down curves were fit to a simplified functional form designed to approximate the behavior of radiative, conductive, and convective heat transfer, yielding a conductivity parameter. This parameter was able to identify minor changes, less than twenty five percent, in the thickness of a single layer of the walls of single-pass, thin-wall structures and the presence of underlying unfused powder. Small voids were not produced in the test prints analyzed here. The thermal signature of underlying fusion defects, as measured by the conductivity parameter, is clearly present for many layers. This method was shown to be effective in detecting changes in conductivity of the material which represents a large portion of the defects commonly found in SLM additive manufacturing

NASA Tech Briefs, February 2001

The topics include: 1) Application Briefs; 2) National Design Engineering Show Preview; 3) Marketing Inventions to Increase Income; 4) A Personal-Computer-Based Physiological Training System; 5) Reconfigurable Arrays of Transistors for Evolvable Hardware; 6) Active Tactile Display Device for Reading by a Blind Person; 7) Program Automates Management of IBM VM Computer Systems; 8) System for Monitoring the Environment of a Spacecraft Launch; 9) Measurement of Stresses and Strains in Muscles and Tendons; 10) Optical Measurement of Temperatures in Muscles and Tendons; 11) Small Low-Temperature Thermometer With Nanokelvin Resolution; 12) Heterodyne Interferometer With Phase-Modulated Carrier; 13) Rechargeable Batteries Based on Intercalation in Graphite; 14) Signal Processor for Doppler Measurements in Icing Research; 15) Model Optimizes Drying of Wet Sheets; 16) High-Performance POSS-Modified Polymeric Composites; 17) Model Simulates Semi-Solid Material Processing; 18) Modular Cryogenic Insulation; 19) Passive Venting for Alleviating Helicopter Tail-Boom Loads; 20) Computer Program Predicts Rocket Noise; 21) Process for Polishing Bare Aluminum to High Optical Quality; 22) External Adhesive Pressure-Wall Patch; 23) Java Implementation of Information-Sharing Protocol; 24) Electronic Bulletin Board Publishes Schedules in Real Time; 25) Apparatus Would Extract Water From the Martian Atmosphere; 26) Review of Research on Supercritical vs Subcritical Fluids; 27) Hybrid Regenerative Water-Recycling System; 28) Study of Fusion-Driven Plasma Thruster With Magnetic Nozzle; 29) Liquid/Vapor-Hydrazine Thruster Would Produce Small Impulses; and 30) Thruster Based on Sublimation of Solid Hydrazin

Central Florida Future, Vol. 37 No. 73, July 20, 2005

Age-specific student housing leads some to wonder if so many freshmen can reside in same apartment complex; Death of friends leaves some students to battle grief: Denial and anger part of multitude of emotions faced when loved ones are lost; New dorms feature high-class amenities: Private parking garage retail shops enhance housing; Shark tales: The beaches that line the coast of Florida attract thousands if surfers every year - and sharks; Online facebooks latest student sensation: Addictive MySpace Thefacebook improve social networking friendship between Internet buddies.https://stars.library.ucf.edu/centralfloridafuture/2838/thumbnail.jp

Superhumps in AM Canum Venaticorum stars

Bibliography: pages 205-214.The AM Canum Venaticorum stars are an in homogeneous group of six stars that are characterised by the absence of hydrogen lines in their spectra. The structure of these stars has been the subject of much debate, and single star models were considered as recently as 1992. The prevailing opinion, however, is that the A.Jf eVn stars are semi-detached binaries which consist of a low-mass, degenerate helium secondary which is transferring mass via an accretion disc to a DB white dwarf. Under this model, the orbital periods of the AM CVn systems are in the range 1000 - 3000 s. The AM CVn systems show many of the accretion disc-related phenomena that are observed in non-magnetic (hydrogen-rich) cataclysmic variables. Five of the six systems show low-amplitude optical oscillations with periods between 500 and 2000 s. The oscillations have a complex and variable harmonic structure. Since they are consistent with the predictions of the double-degenerate binary model, the oscillations were assumed to correspond to the orbital period in each system. However, the fundamental periods and their harmonics are unstable, showing amplitude and phase drifts on a time scale of weeks to months. The instability of the photometric periods has therefore been an obstacle to accepting that the AM CVn stars are binary systems. An alternative explanation was proposed by O'Donoghue & Kilkenny (1989): the photometric variations in the AM CVn stars are not their orbital periods, but are caused by the same mechanism that produces superhumps in SU UMa dwarf novae. Superhumps are optical variations observed during the superoutbursts of SU UMa stars with periods a few percent in excess of the orbital period. The superhumps usually disappear as the star declines to quiescence after a superoutburst. Superhumps are thought to be the result of periodic enhancements of tidal dissipation in the outer regions of the accretion disc. In addition to the superhumps in SU UMa dwarf novae, permanent superhumps have been observed in other hydrogen-rich cataclysmic variables. The aim of this dissertation is to present new photometric data and to explore the period structure of four of the six known AM CVn stars to see whether the observations are consistent with a superhump interpretation. The aim is also to draw comparisons between the AM CVn stars and examples of hydrogen-rich cataclysmic variables in which superhumps have been observed, and in this way to strengthen the evidence that similar mechanisms are operating in the hydrogen-rich superhumpers and the multi periodic AM CVn stars