1,311 research outputs found

    An autonomous rendezvous and docking system using cruise missile technology

    Get PDF
    In November 1990 General Dynamics demonstrated an AR&D system for members of the Strategic Avionics Technology Working Group. This simulation utilized prototype hardware derived from the Cruise Missile and Centaur avionics systems. The object of this proof of concept demonstration was to show that all the accuracy, reliability, and operational requirements established for a spacecraft to dock with Space Station Freedom could be met by the proposed AR&D system

    The importance and art of articulating thanks: Lessons from non-governmental organisations (NGOs)

    Get PDF
    Thanking helps organisations to build relationships. In particular, charities need to thank as they build up coalitions of interest around issues, and as, in many cases, they raise income. So what can be learned from some professional thankers, and scholars, in the NGO sector? You’ll learn: • The importance of thanks in interpersonal communications and NGO communications • What we can learn from NGO sector best practice and guidance • A framework for thanking built on NGO researc

    Lab Demonstration of the Hybrid Doppler Wind Lidar (HDWL) Transceiver

    Get PDF
    The recommended design approach for the 3D Tropospheric Winds mission is a hybrid Doppler lidar which combines the best elements of both a coherent aerosol Doppler lidar operating at 2 microns and a direct detection molecular Doppler lidar operating at 0.355 microns. In support of the mission, we built a novel, compact, light-weighted multi-field of view transceiver where multiple telescopes are used to cover the required four fields of view. A small mechanism sequentially selects both the "transmit" and "receive" fields of view. The four fields are combined to stimulate both the 0.355 micron receiver and the 2 micron receiver. This version is scaled (0.2 m diameter aperture) from the space-based version but still demonstrates the feasibility of the hybrid approach. The primary mirrors were conventionally light-weighted and coated with dielectric, high reflectivity coatings with high laser damage thresholds at both 2 microns and 0.355 microns. The mechanical structure and mounts were fabricated from composites to achieve dimensional stability while significantly reducing the mass. In the laboratory, we demonstrated the system level functionality at 0.355 microns and at 2 microns, raising the Technology Readiness Level (TRL) from 2 to 4

    Enhancing collaboration and community for the discipline of organizing

    Get PDF
    The overall purpose of this workshop is to strengthen the existing collaboration and community among instructors and schools using The Discipline of Organizing (Glushko 2015), to promote further innovation in digital publishing, and to enhance iSchool teaching practices through experimentation with new models of collaborative courses. Information about participation, planning materials, presentations, and follow-up artifacts for the workshop are at disciplineoforganizing.org.

    Societal change and its impact on education: presentations to the WAIER seminar 1980

    Get PDF

    Influence of the initial chemical conditions on the rational design of silica particles

    Get PDF
    The influence of the water content in the initial composition on the size of silica particles produced using the Stöber process is well known. We have shown that there are three morphological regimes defined by compositional boundaries. At low water levels (below stoichiometric ratio of water:tetraethoxysilane), very high surface area and aggregated structures are formed; at high water content (>40 wt%) similar structures are also seen. Between these two boundary conditions, discrete particles are formed whose size are dictated by the water content. Within the compositional regime that enables the classical Stöber silica, the structural evolution shows a more rapid attainment of final particle size than the rate of formation of silica supporting the monomer addition hypothesis. The clearer understanding of the role of the initial composition on the output of this synthesis method will be of considerable use for the establishment of reliable reproducible silica production for future industrial adoption

    Intractable Alcoholism in a Patient with a Levine Shunt

    Get PDF
    Ellen Shaw. M.D., Fellow in Hepatology: Mr. J is a forty-six-year-old white male who was initially seen on the medical service in July 1982. At that time he presented with hepatic encephalopathy, jaundice, and ascites. A liver biopsy was performed, confirming the clinical diagnosis of alcoholic hepatitis superimposed on cirrhosis. Following discharge it was difficult to maintain Mr. J as an outpatient. He did not follow dietary restrictions or take diuretics as prescribed. Additionally he was unable to control his drinking. Finally about a year ago a Levine shunt was implanted in an effort to control his ascites. Subsequently he did well for a period of several months. He was able to abstain from alcohol with a resulting decrease in his ascites and jaundice. Recently he has resumed drinking, with a return of his symptoms. He has missed his last several appointments in the clinic. Control of his medical problems remains problematic unless his alcohol abuse can be better controlled
    corecore