Global ETD Search

1	New model for the 5-20 cm wavelength opacity of ammonia pressure-broadened by methane under jovian conditions based on laboratory measurements Chinsomboon, Garrett 12 October 2012 (has links) In order to fully understand the role methane (CH₄) plays in the microwave emission spectra of the deep atmospheres of the outer planets, over 280 laboratory measurements of the opacity of ammonia in a methane environment have been made in the 5-20 cm wavelength range. All opacity measurements were made with either 100 or 200 mbars of ammonia and with 1 to 3 bars of added methane in the 330-450K temperature range. A formalism for the absorptivity of ammonia broadened by methane has now been developed and had been applied to the Hanley et al. (Icarus, v. 202, 2009) model for the opacity of ammonia. Due to methane's relatively low abundance at Jupiter (~0.2% by volume), its effect on the microwave spectrum which will be observed by the Juno MWR (Microwave Radiometer) will be minimal. However, these experimental results will significantly improve the understanding of the microwave emission spectrum of Uranus and Neptune where methane plays a more dominant role. Planetary atmospheres NASA Juno mission Atmosphere of Jupiter Centimeter-wavelength measurements Methane broadening of ammonia Microwave opacity model Jupiter (Planet) Atmosphere Centimeter waves Microwaves Wavelengths
2	A Feasibility Study of Thin-Shell Deformable Mirrors with Adaptive Truss Support for Spaced-Based Telescopes Marzette, Russell K., Jr. 19 July 2006 (has links) Space-based telescopes are limit by the payload requirements of existing launch vehicles. Thus, despite distinct advantages the resolution of terrestrial telescopes exceeds space-based telescopes due to larger size and powerful adaptive optics. To overcome payload limitations, a primary mirror technology that is lighter in weight, but no less effective, is required. As this will result in new structural conditions, new approaches to maintaining the optical shape (figure) of the mirror will also be required. This thesis culminates work at the Georgia Institute of Technology in modelling a hexagonal thin-shell deformation mirror manipulated by an adaptive truss. This research specifically examines the feasibility of a surface parallel actuated (SPA) thin-shell CuZr deformable mirror (DM) as an alternative to a typical surface normal actuated (SNA) based mirror. It is believed that by using a thin-shell mirror (100 m or less in thickness) with a light weight substrate, such as a truss, that a significant weight-savings will occur, thus enabling larger space based telescopes. This thesis advances the SPA DM concept by 1) creating a representative model, 2) developing design evaluation methods, 3) evaluating the FEA simulated response of the deformable mirror over Zernike error modes, 4) evaluating the FEA simulated response to select thermal loads, and 5) evaluating the ability of the DM to remove thermal error, and the forces required to do so. Finally, it is concluded that overall the SPA DM concept is feasible. Thermal gradient Truss Substrate Facesheet Space Space-based Active optics JPL Xinetics University of Florida NRO Georgia Tech Mirror Lightweight Surface parallel actuator Surface normal actuation Thin-shell Adaptive optics Deformable mirrors
3	A plm implementation for aerospace systems engineering-conceptual rotorcraft design Hart, Peter Bartholomew 08 April 2009 (has links) The thesis will discuss the Systems Engineering phase of an original Conceptual Design Engineering Methodology for Aerospace Engineering-Vehicle Synthesis. This iterative phase is shown to benefit from digitization of Integrated Product&Process Design (IPPD) activities, through the application of Product Lifecycle Management (PLM) technologies. Requirements analysis through the use of Quality Function Deployment (QFD) and 7 MaP tools is explored as an illustration. A "Requirements Data Manager" (RDM) is used to show the ability to reduce the time and cost to design for both new and legacy/derivative designs. Here the COTS tool Teamcenter Systems Engineering (TCSE) is used as the RDM. The utility of the new methodology is explored through consideration of a legacy RFP based vehicle design proposal and associated aerospace engineering. The 2001 American Helicopter Society (AHS) 18th Student Design Competition RFP is considered as a starting point for the Systems Engineering phase. A Conceptual Design Engineering activity was conducted in 2000/2001 by Graduate students (including the author) in Rotorcraft Engineering at the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology, Atlanta GA. This resulted in the "Kingfisher" vehicle design, an advanced search and rescue rotorcraft capable of performing the "Perfect Storm" mission, from the movie of the same name. The associated requirements, architectures, and work breakdown structure data sets for the Kingfisher are used to relate the capabilities of the proposed Integrated Digital Environment (IDE). The IDE is discussed as a repository for legacy knowledge capture, management, and design template creation. A primary thesis theme is to promote the automation of the up-front conceptual definition of complex systems, specifically aerospace vehicles, while anticipating downstream preliminary and full spectrum lifecycle design activities. The thesis forms a basis for additional discussions of PLM tool integration across the engineering, manufacturing, MRO and EOL lifecycle phases to support business management processes. Teamcenter systems engineering Teamcenter community Teamcenter unified Teamcenter engineering Teamcenter manufacturing CATIA V5 Rotorcraft design Boeing AHS Joint heavy lift VPLM MBOM EBOM Product change control Product definition Configuration management Product structure architecture Design engineering Aerospace engineering System engineering PLM CIE IDE SE Affordability Cost savings Executive helicopter Joint chiefs of staff Marine CAE CAD CAM CAA MDO RSM DOE Consulting Engineering management Perfect storm Engineering software Requirements data management CATIA V4 NX Engineering communications RFP Digitization Air Force Navy Army BAMS FIPER ACSYNT Sikorsky Bell Georgia Tech Engineering methodology Requirements engineering System engineering Search Rescue IDE Integrated digital environment Kingfisher Search and rescue Helicopter Helicopter engineering QFD Legacy design IPPD Quality engineering Defense systems acquisition Coast Guard Decision support systems Rotors (Helicopters) Design Concurrent engineering

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