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Wojtecki R.J.,Case Western Reserve University | Meador M.A.,National Aeronautics and Space Administration Glenn Research Center | Rowan S.J.,Case Western Reserve University
Nature Materials | Year: 2011

New materials that have the ability to reversibly adapt to their environment and possess a wide range of responses ranging from self-healing to mechanical work are continually emerging. These adaptive systems have the potential to revolutionize technologies such as sensors and actuators, as well as numerous biomedical applications. We will describe the emergence of a new trend in the design of adaptive materials that involves the use of reversible chemistry (both non-covalent and covalent) to programme a response that originates at the most fundamental (molecular) level. Materials that make use of this approach - structurally dynamic polymers - produce macroscopic responses from a change in the material's molecular architecture (that is, the rearrangement or reorganization of the polymer components, or polymeric aggregates). This design approach requires careful selection of the reversible/dynamic bond used in the construction of the material to control its environmental responsiveness. © 2011 Macmillan Publishers Limited. All rights reserved. Source


Lyons V.J.,National Aeronautics and Space Administration Glenn Research Center
Journal of Aerospace Engineering | Year: 2013

Propulsion and power have long been core competencies of the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC). At the dawn of the space era, the center brought key propulsion and power technology to support spacecraft development. This paper serves as an introduction to a series of papers describing the highlights of the GRC's power and propulsion research and development efforts. The power papers cover solar and nuclear power generation and energy conversion, energy storage (focusing on batteries, flywheels, and fuel cells), power systems, and power management and distribution. The propulsion papers cover chemical propulsion, cryogenic propellant systems, electric propulsion, and nuclear thermal rocket propulsion. Each paper addresses some history, current efforts, and future plans for each of the technology areas. © 2013 American Society of Civil Engineers. Source


Borowski S.K.,National Aeronautics and Space Administration Glenn Research Center
Journal of Aerospace Engineering | Year: 2013

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has been actively involved in nuclear thermal propulsion (NTP) technology development, mission, engine, and vehicle design dating back to the Rover and Nuclear Engine for Rocket Vehicle Applications programs. This technology was successfully developed in over 20 rocket/reactor tests, which demonstrated a wide range of thrust levels, high-temperature fuel, sustained engine operation, accumulated time at full power, and restart capability - everything required for a human mission to Mars. Furthermore, NTP requires no large technology scale-up. The smallest engine tested during the Rover program - the Pewee Engine - is sufficient for this when used in a clustered engine arrangement. The GRC has led every major study involving NTP since the late 1980s and has helped quantify the evolution and growth potential of the nuclear thermal rocket (NTR), which includes the bimodal and liquid-oxygen- (LOX-) augmented NTR concepts. In NASA's recent Mars Design Reference Architecture (DRA) study, NTP reduced total mission mass over 400 t compared with chemical propulsion. Human missions to the Moon and near-Earth asteroids are also enhanced using NTP. In 2011, NASA restarted an NTP technology demonstration effort that is continuing under the Nuclear Cryogenic Propulsion Stage project, which began in 2012. Ground demonstrations of a small, scalable NTR by 2020 are envisioned, with a flight demonstration shortly thereafter. © 2013 American Society of Civil Engineers. Source


Reddy D.R.,National Aeronautics and Space Administration Glenn Research Center
Journal of Aerospace Engineering | Year: 2013

This paper presents a brief overview of air-breathing propulsion research conducted at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) over the last 70 years. It includes a historical perspective of the center and its various stages of propulsion research in response to the country's different periods of crises and growth opportunities. The GRC's research and technology development covered a broad spectrum, from a short-term focus on improving the energy efficiency of aircraft engines to advancing the frontier technologies of high-speed aviation in the supersonic and hypersonic speed regimes. This paper highlights major research programs, showing their impact on industry and aircraft propulsion, and briefly discusses current research programs and future aeropropulsion technology trends in related areas. © 2013 American Society of Civil Engineers. Source


Huff D.L.,National Aeronautics and Space Administration Glenn Research Center
Journal of Aerospace Engineering | Year: 2013

This paper reviews all engine noise research conducted at the National Aeronautics and Space Administration (NASA) Glenn Research Center over the last 70 years. The review includes a historical perspective of the center and the facilities used to conduct the research. Major NASA noise research programs are highlighted, showing their impact on the industry and on the development of aircraft noise reduction technology. Noise reduction trends are discussed, and future aircraft concepts are presented. Results show that, since the 1960s, the average perceived noise level has been reduced by about 20 dB. Studies show that, depending on the size of the airport, the aircraft fleet mix, and the actual growth in air travel, another 15-17 dB is required to achieve NASA's long-term goal of providing technologies to limit objectionable noise to the boundaries of an average airport. © 2013 American Society of Civil Engineers. Source

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