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  • 1
    Electronic Resource
    Electronic Resource
    The photochemistry of methyl cyclobutyl ketone. Part 2. Temperature dependence and the acetyl radical decomposition (1987)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 19 (1987), S. 997-1013 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following earlier room-temperature studies, gaseous mixtures of methyl cyclobutyl ketone (MCK) diluted in argon have been photolyzed at temperatures up to 205°C. Experiments have been carried out at a variety of pressures (up to ca. 2 atm) at wavelengths of 313 nm (steady state conditions) and 308 nm (pulsed photolysis). The results are consistent with a mechanism dominated by radical-radical reactions involving acetyl, methyl, and cyclobutyl radicals. Acetyl radical processes predominate at lower temperatures while methyl radical reactions are more important at high temperatures.The results are interpreted via kinetic modelling of a mechanism in which a key role is played by the acetyl radical decomposition reaction \documentclass{article}\pagestyle{empty}\begin{document}$$ ({\rm M} +)\,{\rm CH}_{\rm 3} {\rm CO}\mathop {\longrightarrow}\limits^{\rm 3} {\rm CH}_{\rm 3} + {\rm CO\, (+ M)} $$\end{document} Values for k3 have been obtained and its temperature and pressure dependence are fitted by RRKM theory and a weak-collisional activation model to yield \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log(}k_3 ^\infty /{\rm s}^{ - 1}) = 13.3 - 17.5{\rm\, kcal\, mol}^{{\rm - 1}} /RT\ln 10 $$\end{document} This high-pressure limiting Arrhenius equation is consistent with other studies in the same temperature range, but is difficult to reconcile with higher temperature investigations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550191105
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Expanding Hardware-in-the-Loop Formation Navigation and Control with Radio Frequency Crosslink Ranging (2007)
    In:  CASI
    Details
    Publication Date: 2018-06-06
    Description: The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility continues to evolve as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation, and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, are reviewed with a focus on recent improvements. With the most recent improvement, in support of Technology Readiness Level (TRL) 6 testing of the Inter-spacecraft Ranging and Alarm System (IRAS) for the Magnetospheric Multiscale (MMS) mission, the FFTB has significantly expanded its ability to perform realistic simulations that require Radio Frequency (RF) ranging sensors for relative navigation with the Path Emulator for RF Signals (PERFS). The PERFS, currently under development at NASA GSFC, modulates RF signals exchanged between spacecraft. The RF signals are modified to accurately reflect the dynamic environment through which they travel, including the effects of medium, moving platforms, and radiated power.
    Keywords: Spacecraft Design, Testing and Performance
    Type: Proceedings of the 20th International Symposium on Space Flight Dynamics; NASA/CP-2007-214158
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.
    Keywords: Spacecraft Design, Testing and Performance
    Type: AIAA Guidance, Navigation and Control Conference and Exhibit; Aug 20, 2007 - Aug 23, 2007; Hilton Head, SC; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Development of a Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and. control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for inter-spacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of medium, moving platforms, and radiated power. The Path Emulator for RF Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.
    Keywords: Space Communications, Spacecraft Communications, Command and Tracking
    Type: AIAA Guidance, Navigation and Control Conference and Exhibit; Aug 20, 2007 - Aug 23, 2007; Hilton Head, South Carolina; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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