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Viewing 1 to 30 of 843
2010-10-25
Journal Article
2010-01-2091
Michael J. Lance, C. Scott Sluder, Samuel Lewis, John Storey
Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with nitrogen oxides (NOx) emissions standards. In order to better understand fouling mechanisms, eleven field-aged EGR coolers provided by seven different engine manufacturers were characterized using a suite of techniques. Microstructures were characterized using scanning electron microscopy (SEM) and optical microscopy following mounting the samples in epoxy and polishing. Optical microscopy was able to discern the location of hydrocarbons in the polished cross-sections. Chemical compositions were measured using thermal gravimetric analysis (TGA), differential thermal analysis (DTA), gas chromatography-mass spectrometry (GC-MS), x-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Mass per unit area along the length of the coolers was also measured.
2010-10-25
Journal Article
2010-01-2254
Russell P. Fitzgerald, Richard R. Steeper
An infrared laser absorption technique has been developed to measure in-cylinder concentrations of CO in an optical, automotive HCCI engine. The diagnostic employs a distributed-feedback, tunable diode laser selected to emit light at the R15 line of the first overtone of CO near 2.3 μm. The collimated laser beam makes multiple passes through the cylinder to increase its path length and its sampling volume. High-frequency modulation of the laser output (wavelength modulation spectroscopy) further enhances the signal-to-noise ratio and detection limits of CO. The diagnostic has been tested in the motored and fired engine, exhibiting better than 200-ppm sensitivity for 50-cycle ensemble-average values of CO concentration with 1-ms time resolution. Fired results demonstrate the ability of the diagnostic to quantify CO production during negative valve overlap (NVO) for a range of fueling conditions.
2004-07-19
Technical Paper
2004-01-2456
Jessica J. Prenger, Susan L. Steinberg, Daniel Haddock, Joey H. Norikane, Howard G. Levine
The WONDER space flight experiment will compare the operation of both substrate-based and porous tube nutrient delivery systems (NDS) under microgravity conditions. Each NDS will be evaluated with three moisture availability regimes, and moisture sensing will be critical for the operation and evaluation of the systems. Orbital Technologies (Madison, WI) has developed a space flight-rated temperature and moisture acquisition system (TMAS) for measuring water content of plant growth medium. The sensors were evaluated in 0.25-1 mm and 1-2 mm baked ceramic aggregate (Profile and Turface, respectively). The sensors' pooled standard deviations ranged from approximately 2% to 5% relative water content (RWC), and root mean square error between sensor RWC and measured RWC was greater than 3% using linear calibration.
2004-11-02
Technical Paper
2004-01-3092
Zenovy S. Wowczuk, Kenneth H. Means, Victor H. Mucino, Gregory J. Thompson, James Smith, Jeffery R.X Auld, James E. Smith, Adam Naternicola, Lawrence Anthony Feragotti, Bruce J. Corso
The development of a standardized roll-on, roll-off (RoRo) sensor pallet system for a C-130 aircraft was conceived by the National Guard and the Counter Narco-Terrorism Technology Development Office to assist in counterdrug reconnaissance activities within the United States and surveillance and reconnaissance missions worldwide. West Virginia University was contracted to perform the design and development of this system because of their innovative design ideas. Before development, the design parameters were established by these two DoD agencies, their mission requirements and by the limitations of the C-130 aircraft. These limitations include using Commercial off the Shelf (COTS) and Government off the Shelf (GOTS) items when developing the system that must be universal on all C-130 aircrafts variants B thru H. Further design criteria are by the limitations of the C-130 aircraft and its existing mission requirements.
2011-06-13
Technical Paper
2011-38-0051
Jamie Braid, Patrick Van Wie, Jeffrey Rex
Aircraft icing continues to be a challenge for the aviation community. Icing is predominantly reported by pilots based on subjective visual observations of relatively small ice thicknesses at distances greater than such estimates can consistently be made. While some technologies exist to sense the presence of aircraft icing, there is a need to objectively sense the presence of ice, determine the rate of ice accumulation, and concurrently measure weather conditions to support, validate, and report the icing indication. AirDat LLC has developed an airborne atmospheric sensing device that includes a built-in ice detector which transmits icing information directly to the ground in real time. These data can be received directly by the aircraft operator or provided to any number of aviation entities to improve the safety of the National Air Space (NAS).
2004-11-02
Technical Paper
2004-01-3129
Zenovy S. Wowczuk, Kenneth H. Means, Victor H. Mucino, Gregory J. Thompson, Lawrence Feragotti, James E. Smith, Adam Naternicola, Bruce J. Corso
Abstract During structural engineering design two of the most overlooked design facets of a finished product is understanding the behavior characteristics of how the product will react when resonated at its natural frequencies and actually defining and understanding the overall vibration profile responsible for the excitation of the structure. A C-130 mechanical arm/pod system has been developed to accommodate 1,000-pounds of sensor payload deployable in flight from a C-130 Hercules military aircraft (variants B thru J). The mechanical arm/pod system will be subjected to a profile of vibration from numerous sources during deployment and while in the final operating position. A general vibration profile for the mechanical arm/pod will be compiled from the plane’s four T-56-A-15 turboprop engines, the atmospheric turbulence and random gust loads.
2004-07-19
Technical Paper
2004-01-2391
Michele Cairola, Roberto Passini, Federica Tessarin, Ludovic Ouchet, Claudio Damasio
ESA has planned two important missions for performing astronomical investigations in the infrared and sub-millimetre wavelength range: Herschel satellite has an observatory type mission and is the fourth cornerstone mission (CS4) of the “Horizon 2000” programme. It will carry three instruments (HIFI, SPIRE, and PACS) for high and medium resolution spectroscopy, imaging and photometry over the sub-millimetre and far-infrared range. A 3.5 m telescope will focus the incoming radiation on the Focal Plane Units of these instruments. Planck satellite has a survey type mission and is the third Medium mission (M3) of the “Horizon 2000” programme. It will provide a definitive high-angular resolution map of the cosmic microwave background anisotropies over at least 95% of the sky and over a wide frequency range. A 1.5 m telescope will focus the incoming radiation on the focal plane shared by the two instruments (LFI and HFI).
2004-07-19
Technical Paper
2004-01-2542
Josef B. Simeonsson, Muhsin Ezer
Studies are being performed to investigate the feasibility of surface enhanced Raman scattering (SERS) spectrometry for monitoring volatile organic compounds (VOCs) in air. The focus of these studies has been on the development and characterization of substrate materials that can be used for SERS measurements. The studies have shown that substrates can be fabricated that provide high SERS sensitivity and selectivity. Substrates include Au or Ag nanoparticles immobilized on silica or deposited on paper supports. Measurements of a model compound have shown that enhancements as high as 1010 to 1012 can be achieved. Several VOC analytes have been investigated by SERS detection approaches, including indole, dimethyl sulfide, quinoline and benzoic acid. Studies have shown that substrates based on immobilized Au or Ag nanoparticles can be modified with surface coatings to enhance their SERS response.
2004-07-19
Technical Paper
2004-01-2541
James D. Tatara, Jay L. Perry
Since the beginning of the crewed space exploration program, the National Aeronautics and Space Administration (NASA) recognized the need to monitor the composition of a spacecraft cabin atmosphere. Typically, major constituent monitoring has been limited to nitrogen, oxygen, carbon dioxide, and water vapor. For the International Space Station, mass spectroscopy was selected as the baseline technology for this task. Recently, new techniques for monitoring major atmospheric constituents have matured commercially making them viable for crewed spacecraft applications. These techniques have advantages over the mass spectroscopy and electrochemically-based instruments used on board the ISS and Shuttle. Fast laser diode oxygen analysis, solid-state infrared carbon dioxide detection, and thin-film capacitive humidity detection are among the emerging techniques.
2012-10-22
Technical Paper
2012-01-2230
Yeong-Ren Lin, Yang Hu, Lei Zhou, David Woodburn, Thomas Wu, Louis C. Chow, Quinn Leland
In the aviation community, there is a high priority to develop all-electric aircraft. Electro-mechanical actuation systems would replace traditional, large, heavy and difficult-to-maintain hydraulic actuation systems. This movement from hydraulic actuation to electrical actuation enhances the flexibility to integrate redundancy and emergency system in future military aircraft. Elimination of the hydraulic fluid removes the possibility of leakage of corrosive hydraulic fluid and the associated fire hazard, as well as environmental concerns. The switch from hydraulic to electrical actuation provides additional benefits in reduced aircraft weight, improved survivability and improved maintainability. The heat load in an electro-mechanical actuation (EMA) is highly transient and localized in nature; therefore a phase change material could be embedded in the heat generating components to store peak heat load.
2012-10-22
Technical Paper
2012-01-2232
Yang Hu, David Woodburn, Yeong-Ren Lin, Thomas Wu, Louis C. Chow, Quinn Leland
In all-electric aircraft, electromechanical actuators (EMAs) will be used to replace hydraulic actuators. Due to the highly transient mission profiles of the aircraft operation, thermal management of EMAs is a significant issue. In this paper, we study the heat problem of the control and drive units of EMAs, and build a model to calculate and simulate the power loss and heat generation in the driver board. The driver unit consists of a power inverter, a capacitor, a power dissipating resistor and a control circuit. The power loss of each component is studied. The heat loss in the power inverter comes mainly from the power switches: IGBTs. The on-state loss is proportional to the current of the motor, and the switching loss is determined by the switching frequency as well as current.
2012-10-22
Journal Article
2012-01-2208
Dennis P. Shay, Clive A. Randall
Mn and/or rare earth-doped xCaTiO₃ - (1-x)CaMeO₃ dielectrics, where Me=Hf or Zr and x=0.7, 0.8, and 0.9 were developed to yield materials with room temperature relative permittivities of Εr ~ 150-170, thermal coefficients of capacitance (TCC) of ± 15.8% to ± 16.4% from -50 to 150°C, and band gaps of ~ 3.3-3.6 eV as determined by UV-Vis spectroscopy. Un-doped single layer capacitors exhibited room temperature energy densities as large as 9.0 J/cm₃, but showed a drastic decrease in energy density above 100°C. When doped with 0.5 mol% Mn, the temperature dependence of the breakdown strength was minimized, and energy densities similar to room temperature values (9.5 J/cm₃) were observed up to 200°C. At 300°C, energy densities as large as 6.5 J/cm₃ were measured. These observations suggest that with further reductions in grain size and dielectric layer thickness, the xCaTiO₃ - (1-x)CaMeO₃ system is a strong candidate for integration into future power electronics applications.
1958-01-01
Technical Paper
580166
JOHN BURNETT, DONALD MOSES
This paper will present the concensus of current thinking relative to the desirable approaches to the design of controls for Thrust Reversing actuation. Two general categories of controls will be advanced, one for the system restricted to initiation during landing roll, the other for initiation during flight. An actuation system which has been under development for the past 18 months will be discussed in relation to the requirements of the two major control categories presented. (Figs. 11 & 12).
2007-09-17
Technical Paper
2007-01-3846
Joseph J. Kehoe, Rick Lind
Unmanned aerial vehicles (UAVs) stand to play a significant role in future sensing and information gathering missions. The scope of these mission scenarios is expanding to include those missions for which the sensor and carrier vehicle will be in close proximity to the surrounding environment, such as in urban operations. Several unique problems related to guidance, navigation and control are introduced that separate these tasks from the existing paradigm for information gathering missions at standoff range. This paper examines the challenges related to autonomous sensor planning missions in these close proximity environments and discusses solution strategies to achieve maximal sensing effectiveness. Specifically, results from vision-based navigation research are discussed and the concept of a geometric sensing effectiveness criterion is introduced and subsequently utilized for motion planning.
2007-09-17
Technical Paper
2007-01-3847
Robert N. Schmidt, Mehul P. Patel
The Wright Brothers invented flight control on heavier than air craft by introducing wing warping on the 1899 Wright glider. Second-generation flight control systems using the aileron were developed shortly thereafter. For the past century, this has been the state-of-the-art for controlling aircraft. Starting in the early 1990s, third generation flight control systems have been developed using new micro-scale actuators and advanced algorithms that focus on controlling the boundary layer, rather than the bulk airflow. Built on the theory of boundary-layer flow control by Prandtl in 1904, today's modern flow control concepts and devices offer significant advantages and benefits compared to conventional movable control surfaces for air vehicle control.
2009-07-12
Technical Paper
2009-01-2471
Roedolph A. Opperman, James M. Waldie, Alan Natapoff, Dava J. Newman, Jason Hochstein, Luca Pollonini, Rafat R. Ansari, Jeffrey A. Jones
The aim of this study was to explore if fingernail delamination injury following EMU glove use may be caused by compression-induced blood flow occlusion in the finger. During compression tests, finger blood flow decreased more than 60%, however this occurred more rapidly for finger pad compression (4 N) than for fingertips (10 N). A pressure bulb compression test resulted in 50% and 45% decreased blood flow at 100 mmHg and 200 mmHg, respectively. These results indicate that the finger pad pressure required to articulate stiff gloves is more likely to contribute to injury than the fingertip pressure associated with tight fitting gloves.
2009-07-12
Technical Paper
2009-01-2470
David Zuniga, Steven D. Hornung, Jon P. Haas, John C. Graf
Fire detection, post fire atmospheric monitoring, fire extinguishing, and post fire atmospheric cleaning are vital components of a spacecraft fire response system, Preliminary efforts focused on the technology evaluation of fire detection, post fire atmospheric monitoring and post fire cleanup systems under realistic conditions are described in this paper. While the primary objective of testing is to determine the performance of a smoke mitigation filter, supplemental evaluations measuring the smoke-filled chamber handheld Commercial Off The Shelf (COTS) atmospheric monitoring devices (combustion product monitors) are conducted. The test chamber consists of a 1.4 cubic meter (50 cu. ft.) volume containing a smoke generator.
2009-11-10
Technical Paper
2009-01-3221
George T. McWilliams, Kevin J. Alley
The objective of this research was to investigate the feasibility of using visual sensor technology to estimate the UAV's pitch, roll, and groundspeed for future use in advanced flight controls. In order to perform the investigation, a simulation environment was implemented for vision-based control of a UAV. The environment included a Simulink model of a generic UAV, including the flight dynamics, flight controller, and sensors. It also included an open-source graphical simulation, which is able to simulate vision sensors at any location and orientation on the aircraft. The images from the simulated vision sensors were fed back to the Simulink model through a frame grabber.
2009-11-10
Technical Paper
2009-01-3175
Helge Sachs, Marcus H. Gojny, Udo B. Carl
System failures represent critical design cases for the development of an actuation control system and its integration in the surrounding structures of any new aircraft. With the focus on oscillatory and transient actuation system failures, this paper presents a method that uses analytical redundancy for the robust detection of such failure cases with minimum sensor equipment. Additional background information is given about the causes for the occurrence of such flight control system failures. Particular focus is here on failures leading to control surface oscillations, so-called Oscillatory Failure Cases (OFCs). Compared to classical signal-based concepts, the benefits of the proposed model-based detection approach are lowered detection amplitudes and reduced detection times. This allows for a considerable reduction in the corresponding failure case load levels that can determine the dimensioning of the airframe structure.
2009-07-12
Technical Paper
2009-01-2542
Brian M. Sutin, William Niu, George Steiner, William O'Hara, John F. Lewis
The Orion Crew Exploration Vehicle (CEV) requires a smoke detector for the detection of particulate smoke products as part of the Fire Detection and Suppression (FDS) system. The smoke detector described in this paper is an adaptation of a mature commercial aircraft design for manned spaceflight. Changes made to the original design include upgrading the materials and electronics to space-qualified components, and modifying the mechanical design to withstand launch and landing loads. The results of laboratory characterization of the response of the new design to test particles are presented.
2008-03-30
Technical Paper
2008-36-0533
Alain Girard, Etienne Cavro, Alain Launay
Natural input modal testing, or ambient vibration testing, or operational modal analysis, consists in extracting modal parameters of the structure excited by its natural operating loads using only its responses, contrary to classical modal analysis where the excitation is also known. In the space area, a classical approach but compatible with an interactive session was developed to reduce cost and development time of the structure by performing modal identification during its vibration qualification campaign. This method, called RTMVI (Real Time Modal Vibration Identification) and based on modal effective parameter concept can be adapted to natural input modal testing. This paper describes the method and its adaptations to this new context.
2005-11-22
Technical Paper
2005-01-4081
Paulo Henriques Iscold Andrade de Oliveira, Frederico Mol Alvares da Silva
2005-07-11
Technical Paper
2005-01-2964
Pete Bonasso, Cheryl Martin
This paper describes the design of an intelligent control software architecture for advanced life support (ALS) applications that is dynamically reconfigurable. Such an architecture will dramatically decrease the downtime of ALS systems due to subcomponent failure and will improve safety and operational efficiency by supporting reconfiguration of the control system with a minimum of deactivation or shutdown of the systems being controlled. In addition to increasing system reliability and safety in deployed ALS systems, this architecture will also support ALS technology advancement by allowing the rapid integration of newly developed sensors, actuators and/or control algorithms for evaluation or comparison purposes in ALS ground test beds. Detailed discussion is given for the motivation as well as the design of both the architecture and experiments to validate the architecture’s improvement over current designs.
2005-07-11
Technical Paper
2005-01-2952
Howard G. Levine, Jessica J. Prenger, Donna T. Rouzan, April C. Spinale, Trevor Murdoch, Kevin A. Burtness
The development of a spaceflight-rated Porous Tube Insert Module (PTIM) nutrient delivery tray has facilitated a series of studies evaluating various aspects of water and nutrient delivery to plants as they would be cultivated in space. We report here on our first experiment using the PTIM with a software-driven feedback moisture sensor control strategy for maintaining root zone wetness level set-points. One-day-old wheat seedlings (Tritium aestivum cv Apogee; N=15) were inserted into each of three Substrate Compartments (SCs) pre-packed with 0.25–1 mm Profile™ substrate and maintained at root zone relative water content levels of 70, 80 and 90%. The SCs contained a bottom-situated porous tube around which a capillary mat was wrapped. Three Porous Tubes were planted using similar protocols (but without the substrate) and also maintained at these three moisture level set-points. Half-strength modified Hoagland’s nutrient solution was used to supply water and nutrients.
2005-07-11
Technical Paper
2005-01-2951
Rebecca M. Newman, Gerard J. Kluitenberg, Susan L. Steinberg
The dual-probe heat-pulse (DPHP) method uses temperature increase with time after heating to measure soil heat capacity, which then is related to soil volumetric water content. The coarse-textured plant growth media being considered for spaceflight applications may lead to problems in contact resistance between the medium and the probes of the DPHP sensor, which may limit the effectiveness of the method. The DPHP method was evaluated in 0.25-1 mm and 1-2 mm fritted clay media. Specific heat, determined using differential scanning calorimetry, was 830 J kg−1 °C−1 at 20 °C for the 0.25-1 mm medium and 810 J kg−1 °C−1 at 20 °C for the 1-2 mm medium. Good agreement between sensor measurements and independent water content measurements obtained through oven-drying was indicated by a linear regression of y = 1.00x + 0.0087 and a standard error of 0.04 cm3 cm−3. The DPHP method can be used to accurately monitor water content in the coarse media being considered for spaceflight applications.
2005-07-11
Technical Paper
2005-01-2889
Neil C. Dias, James S. Fritz, Marc D. Porter
Preliminary results on the development of quick, simple analytical method for the low level of lead(II) in water samples are described. The method concentrates lead(II) on a small solid-phase extraction disk, which is then quantified directly on the disk by diffuse reflectance spectroscopy (DRS). This method, termed colorimetric solid-phase extraction (C-SPE), requires only 1–2 min for complete workup and is suitable for use in a wide range of applications, including the microgravity environment on the International Space Station. The procedure first adds an excess of potassium iodide to a 10.0 mL sample at a pH of 3.0–3.5 to produce the anionic PbI42− colored complex, which is exhaustively extracted by the disk that was previously impregnated with cetylpyridinium chloride (CPC). The amount of complex extracted is then determined at 420 nm by a hand-held DRS instrument.
2005-07-11
Technical Paper
2005-01-2890
Chien-Ju Shih, Neil C. Dias, Marc D. Porter
Contamination of spacecraft water by heavy metals, such as cadmium and lead, is of growing concern. As a consequence, there is need for a rapid, on-board, easy-to-use method for the determination of cadmium(II) at low ppb levels in spacecraft drinking water supplies. This paper describes the preliminary development of a method for the selective, low level determination of cadmium(II) based on colorimetric-solid phase extraction (C-SPE) [1, 2]. In C-SPE, an analyte is extracted from a water sample onto a membrane that has been previously impregnated with a colorimetric reagent, and then quantified as its colorimetric complex directly on the membrane surface using diffuse reflectance spectroscopy. Results from preliminary tests that screened the performance of 1-(4-nitrophenyl)-3-(4-phenyl-azophenyl)triazene (cadion), and organic dyes, rhodamine B, brilliant green, and methyl violet as colorimetric reagents for potential use in a C-SPE analysis of cadmium(II) are described.
2005-07-11
Technical Paper
2005-01-2877
M.S. Hull, R.L. Van Tassell, C.D. Pennington, M. Roman
Researchers at Luna Innovations Inc. and the National Aeronautic and Space Administration's Marshall Space Flight Center (NASA MSFC) are developing an integrated fiber-optic sensor system for real-time monitoring of chemical contaminants and whole-cell bacterial pathogens in water. The system integrates interferometric and evanescent-wave optical fiber-based sensing methodologies to provide versatile measurement capability for both micro- and nano-scale analytes. Sensors can be multiplexed in an array format and embedded in a totally self-contained laboratory card for use with an automated microfluidics platform.
2005-07-11
Technical Paper
2005-01-2878
Roman V. Kruzelecky, Brian Wong, Jing Zou, Wes Jamroz, Mohamed Soltani, Mohamed Chaker, Wanping Zheng, Linh Ngo-Phong
Manned space systems have many requirements for the monitoring of vital life support systems including quality of cabin air and the recycled water supply, as well as direct monitoring of vital indicators of astronaut health. Infrared (IR) spectroscopy is an attractive monitoring technique because it requires minimal consumables while providing relatively high chemical specificity for the detection of a wide variety of biochemicals using the characteristic vibrational modes of chemical bonds. For space-based systems, the important drivers are reliability, power consumption, mass and simplicity of operation. MPB has advanced its IOSPEC™ technology for miniature integrated IR spectrometers to provide performance comparable to large bench-top IR systems but in a compact and ruggedized footprint weighing under 2.5 kg.
2005-07-11
Technical Paper
2005-01-2875
Horia-Nicolai Teodorescu, Ciprian Zamfir
A new type of systems, including in a single system multiple sensors and correlating measuring with feature analysis capabilities and control capabilities, is presented. The new systems are based on nonlinear dynamics and mimic living organism functions and sensing-control abilities. The patented systems comprise a nonlinear system that includes several sensors as elements of the system and whose dynamic is essentially chaotic. The characterization of the nonlinear dynamics (chaotic regime) reveals the intimate correlation between the values the sensors measure, thus evidencing features and patterns in the measured space. These patterns, at their turn, produce a specific control action. Several experimental examples of sensing-monitoring-control systems are presented and their advantages in space applications are discussed.
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