20,537 research outputs found
Forced-flow once-through boilers
A compilation and review of NASA-sponsored research on boilers for use in spacecraft electrical power generation systems is presented. Emphasis is on the heat-transfer and fluid-flow problems. In addition to space applications, much of the boiler technology is applicable to terrestrial and marine uses such as vehicular power, electrical power generation, vapor generation, and heating and cooling. Related research areas are discussed such as condensation, cavitation, line and boiler dynamics, the SNAP-8 project (Mercury-Rankine cycle), and conventional terrestrial boilers (either supercritical or gravity-assisted liquid-vapor separation types). The research effort was directed at developing the technology for once-through compact boilers with high heat fluxes to generate dry vapor stably, without utilizing gravity for phase separations. A background section that discusses, tutorially, the complex aspects of the boiling process is presented. Discussions of tests on alkali metals are interspersed with those on water and other fluids on a phenomenological basis
Analysis and acoustooptical measurements of bulk and surface acoustic wave fields
The development of multielement ultrasonic transducers having full field amplitude and phase control is discussed. In addition, the measurement of the surface particle displacement caused by an idealized impulse load on the surface, the three dimensional mapping of acoustic fields using optical scanning techniques, and the measurement of two dimensional stress distributions using embedded optical fiber sensors are addressed
Workshop on Drought Forecasting for Northeast Brazil
Precipitation forecasting parameters for northeast Brazil were developed. Hydrological, sociological, and economic aspects were examined. A drought forecasting model is presented
James J. Kaput (1942â2005) imagineer and futurologist of mathematics education
Jim Kaput lived a full life in mathematics education and we have many reasons to be grateful to him, not only for his vision of the use of technology in mathematics, but also for his fundamental humanity. This paper considers the origins of his âbig ideasâ as he lived through the most amazing innovations in technology that have changed our lives more in a generation than in many centuries before. His vision continues as is exemplified by the collected papers in this tribute to his life and work
KSC Facilities Status and Planned Management Operations
This is a status report on the facilities and planned operations at the Kennedy Space Center that will support Space Shuttle launches, the first of which is now scheduled for late 1979. The facilities are essentially complete, with all new construction and modifications to existing buildings almost finished. Some activity is still in progress at Pad A and on the Mobile Launcher, due to changes in requirements, but is not expected to impact the launch schedule. The installation and testing of the ground checkout equipment that will be used to test the fIight hardware is now in work. The Launch Processing System is currently supporting the development of the applications software that will perform the testing of this fIight hardware.
The Shuttle Program is unique to past manned space programs in that very tight budgetary constraints have been imposed in an effort to keep the costs low. For KSC, this means adopting a philosophy of launch-to-cost. In an era of routine space flight, this presents a very real challenge to management; the necessity of controlling costs while maintaining tight schedules. An overview of how this management challenge is to be met will be presented
Tele-operated high speed anthropomorphic dextrous hands with object shape and texture identification
This paper reports on the development of two number of robotic hands have been developed which focus on tele-operated high speed anthropomorphic dextrous robotic hands. The aim of developing these hands was to achieve a system that seamlessly interfaced between humans and robots. To provide sensory feedback, to a remote operator tactile sensors were developed to be mounted on the robotic hands. Two systems were developed, the first, being a skin sensor capable of shape reconstruction placed on the palm of the hand to feed back the shape of objects grasped and the second is a highly sensitive tactile array for surface texture identification
The political economy of the Jospin government
This article explores the political economy of the French Socialist Party (PS), beginning with the neo-liberal U-turn of 1983. It then charts the re-evaluation of the PS's political economic foundations after the 1993 defeat, the rejection of the neo-liberal 'pensée unique', and the rehabilitation of a broadly Keynesian frame of reference. The article goes on to explore how this shift has fed through into the Jospin government's policy and positions at both the national and international level. It explores aspirations to reinvent the EU as a Keynesian social democratic 'policy space', and at the national level, employment, macroeconomic, and structural policies
The fundamental cycle of concept construction underlying various theoretical frameworks
In this paper, the development of mathematical concepts over time is considered. Particular reference is given to the shifting of attention from step-by-step procedures that are performed in time, to symbolism that can be manipulated as mental entities on paper and in the mind. The development is analysed using different theoretical perspectives, including the SOLO model and various theories of concept construction to reveal a fundamental cycle underlying the building of concepts that features widely in different ways of thinking that occurs throughout mathematical learning
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