| Experimental Study of Auto-Ignition Phenomena in Swirl-Stabilized LPP Flames in Gas Turbine Model Combustors using kHz Framerate OH-PLIF and Stereo-PIV |
Jan 2012 |
28 pages |
| Authors:
Isaac G Boxx; DEUTSCHES ZENTRUM FUR LUFT-UND RAUMFAHRT STUTTGART (GERMANY)
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 | Long-duration, kHz-framerate OH-PLIF measurements were analyzed to determine the physical mechanism responsible for a previously observed phenomenon wherein isolated pockets of high OH-concentration fluid suddenly appear in regions of unburned gas away from the contiguous flame zone in a gas turbine model combustor. Prior research on the burners indicate these isolated flame-kernels may result either from auto-ignition of hot, unburned reactants upstream of the primary flame or from transport of ... |
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| Direct-Coupled Plasma-Assisted Combustion Using a Microwave Waveguide Torch |
Dec 2011 |
8 pages |
| Authors:
Stephen Hammack; Xing Rao; Tonghun Lee; Campbell Carter; MICHIGAN STATE UNIV EAST LANSING DEPT OF MECHANICAL ENGINEERING
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| A tunable microwave waveguide is used to initiate and enhance combustion by coupling an atmospheric plasma discharge to a premixed methane/air flame. The absorbed microwave power ranges from 60 to 150 W, which was generated from a continuous source operating at 2.45 GHz, whereas combustion power ranges from 200 to 1000 W. OH radical number densities were measured using planar laser-induced fluorescence (PLIF) and temperatures were measured using Rayleigh scattering ... |
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| Laser Diagnostics Study of Plasma Assisted Combustion for Scramjet Applications |
Dec 2011 |
31 pages |
| Authors:
Tonghun Lee; MICHIGAN STATE UNIV EAST LANSING DEPT OF MECHANICAL ENGINEERING
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| The main goal of this study is to apply advanced laser imaging and optical diagnostics to study the physicochemical impact of nonequilibrium plasmas to enhance the conversion of chemical energy in combustion, and to investigate new efficient concepts for coupling plasma energy into a flame, seeking future potential application in high speed engines including scramjets. Three separate topics have been investigated within the scope of this objective. The first topic ... |
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| Advanced Plasma Propulsion |
Nov 2011 |
145 pages |
| Authors:
Edgar Choueiri; Mark A Cappelli; Manuel Martinez-Sanchez; Ashley Hallock; Stephen Gildea; Taylor Matlock; PRINCETON UNIV NJ
|
| This final technical report documents an extensive experimental and theoretical effort, sponsored by AFOSR under Dr. Mitat Birkan and coordinated between research groups at three universities (MIT, Princeton, Stanford) dealing with two main branches of plasma propulsion: Branch I) Ion production and acceleration from non-annular, magnetically insulated thrusters. Branch II) Electrodeless inductive plasma propulsion, specifically the Faraday Accelerator with RF-Assisted Discharge and Conical Theta Pinch (FARAD+CTP). |
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| Next Generation of Advanced Laser Fluorescence Technology for Characterization of Natural Aquatic Environments |
30 Sep 2011 |
17 pages |
| Authors:
Alexander Chekalyuk; Andrew Barnard; Mati Kahru; LAMONT-DOHERTY EARTH OBSERVATORY PALISADES NY
|
| The project research addresses our long-term goal to develop an analytical suite of the Advanced Laser Fluorescence (ALF) methods and instruments to improve our capacity for characterization of aquatic environments. The ALF technique uniquely combines spectrally and temporally resolved measurements of the laser-stimulated emission (LSE) to provide assessments of key variables, including chlorophyll a (Chl a), chromophoric dissolved organic matter (CDOM), and phycobiliprotein-containing phytoplankton and cyanobacteria. The pump-during-probe measurements of ... |
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| Next Generation of Advanced Laser Fluorescence Technology for Characterization of Natural Aquatic Environments |
Sep 2011 |
17 pages |
| Authors:
Alexander Chekalyuk; Andrew Barnard; Mati Kahru; COLUMBIA UNIV PALISADES NY LAMONT-DOHERTY EARTH OBSERVATORY
|
| The project research addresses our long-term goal to develop an analytical suite of the Advanced Laser Fluorescence (ALF) methods and instruments to improve our capacity for characterization of aquatic environments. The ALF technique (Chekalyuk and Hafez, 2008) uniquely combines spectrally and temporally resolved measurements of the laser-stimulated emission (LSE) to provide assessments of key variables, including chlorophyll a (Chl alpha), chromophoric dissolved organic matter (CDOM), and phycobiliprotein-containing phytoplankton and cyanobacteria. ... |
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| Ion Velocity and Plasma Potential Measurements of a Cylindrical Cusped Field Thruster |
19 May 2011 |
13 pages |
| Authors:
N A MacDonald; C V Young; M A Cappelli; Jr Hargus W A; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIR/SPACE AND MISSILE PROPULSION DIV
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| Measurements of the most probable time-averaged axial ion velocities and plasma potential within the acceleration channel and in the plume of a straight channeled cylindrical cusped field thruster operating on xenon are presented. Ion velocities for the thruster are derived from laser-induced fluorescence measurements of the 5d[4](7/2)-6p[3](5/2) xenon ion excited state transition centered at _ = 834.72 nm. Plasma potential measurements are made using a floating emissive probe with a ... |
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| Yip - Development and Application of a High-Speed Three-Dimensional Density Measurement Technique for Aero-Optic Applications |
25 Mar 2011 |
96 pages |
| Authors:
Brian S Thurow; AUBURN UNIV AL DEPT OF AEROSPACE ENGINEERING
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| A density measurement technique based on the planar laser induced fluorescence (PLIF) of acetone vapor was developed and shown to be practical for 2-D density measurements in a high speed wind transonic wind tunnel. The random uncertainty in density measurements was estimated to be on the order of 8% without pixel binning and as low as 3% with pixel binning, thus showing that acetone PLIF is a viable technique for ... |
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| Combustion Dynamics for Energetically Enhanced Flames Using Direct Microwave Energy Coupling |
Jan 2011 |
9 pages |
| Authors:
Xing Rao; Kadek Hemawan; Indrek Wichman; Campbell Carter; Timothy Grotjohn; Jes Asmussen; Tonghun Lee; MICHIGAN STATE UNIV EAST LANSING DEPT OF MECHANICAL ENGINEERING
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| An atmospheric high-Q re-entrant cavity applicator is used to couple microwave (2.45 GHz) electromagnetic energy directly into the reaction zone of a premixed laminar methane-oxygen flame for flame enhancement. As microwave energy increases, a transition from electric field enhancement to microwave plasma discharge is observed. At low microwave powers (1-5 W), the flame is influenced by an electromagnetic field only. When power is increased, ionization and eventually breakdown of gas ... |
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| Magnesium Chemistry in the Upper Atmosphere |
20 DEC 2010 |
22 pages |
| Authors:
John M. Plane; LEEDS UNIV (UNITED KINGDOM) SCHOOL OF CHEMISTRY
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| Metallic species are deposited into the Earth's upper atmosphere by the ablation of approximately 50 tonnes of interplanetary dust that enters the atmosphere each day. The dust undergoes frictional heating to its melting point (approx. 1800 K), after which metallic species ablate and are deposited in the mesosphere-lower thermosphere (MLT) region of the atmosphere (70-120 km). Magnesium is one of the most abundant metals in the MLT, with layers of ... |
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| Combustion Dynamics of Plasma-Enhanced Premixed and Nonpremixed Flames |
Dec 2010 |
8 pages |
| Authors:
Xing Rao; Steve Hammack; Tonghun Lee; Campbell Carter; Igor B Matveev; MICHIGAN STATE UNIV EAST LANSING DEPT OF MECHANICAL ENGINEERING
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| Combustion dynamics are investigated for plasma-enhanced methane-air flames in premixed and nonpremixed configurations using a transient arc dc plasmatron. Planar laser-induced fluorescence images of hydroxyl (OH) and carbon monoxide (CO) radicals are obtained over a range of equivalence ratios (phi = 0.7-1.3), flow rates (6-18 LPM), and plasma powers (100-900 mA) to monitor radical propagation and in situ fuel reforming. The flow rates presented here are outside the range of ... |
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| Planar Laser Imaging of Scattering and Fluorescence of Zooplankton Feeding in Layers of Phytoplankton in situ |
30 SEP 2010 |
13 pages |
| Authors:
Peter J. Franks; Jules S. Jaffe; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
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| We intend to quantify the biological, physical, and chemical dynamics that structure marine planktonic ecosystems. Observations of the organisms and their environment on the spatial and temporal scales that characterize their interactions, combined with models of the dominant dynamics, will lead to improved understanding of the dynamics, structure, and function of planktonic ecosystems. Our objectives in this work are to 1) visualize and quantify herbivorous copepod feeding in the laboratory, ... |
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| Green and Ultraviolet Pulse Generation with a Compact, Fiber Laser, Chirped-Pulse Amplification System for Aerosol Fluorescence Measurements |
APR 2010 |
7 pages |
| Authors:
Janet W. Lou; Marc Currie; Vasanthi Sivaprakasam; Jay D. Eversole; NAVAL RESEARCH LAB WASHINGTON DC OPTICAL SCIENCES DIV
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| We use a compact chirped-pulse amplified system to harmonically generate ultra-short pulses for aerosol fluorescence measurements. The seed laser is a compact, all-normal dispersion, mode-locked Yb-doped fiber laser with a 1050-nm center wavelength operating at 41 MHz. Average powers of more than 1.2 W at 525 nm and 350 mW at 262 nm are generated high-dispersion fiber, amplified by a high-power, large-mode area fiber amplifier, and recompressed using a chirped ... |
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| Nozzles for Focusing Aerosol Particles |
Oct-2009 |
22 pages |
| Authors:
Yong-Le Pan; John Bowersett; Steven C Hill; Ronald G Pinnick; Richard K Chang; ARMY RESEARCH LAB ADELPHI MD COMPUTATIONAL AND INFORMATION SCIENCES DIRECTORATE
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| We report on the design, fabrication, and testing of nozzles that we have used for single-particle sampling measurements of laser-induced fluorescence and two-dimensional angular optical scattering. Single-piece nozzles and a two-piece nozzle with a sheath flow are described. |
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| Chemical Reactivity as a Probe of Ionic-Liquid Surfaces |
30-Apr-2009 |
18 pages |
| Authors:
Kenneth McKendrick; Carla Waring; Paul A Bagot; Matthew L Costen; HERIOT-WATT UNIV EDINBURGH (UNITED KINGDOM)
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| This report results from a contract tasking Heriot-Watt University as follows: The work will be similar to that which the group has pioneered in related studies of the reactions of O(3P) atoms with hydrocarbon liquids. It is based on laser-photolysis of a low pressure of a suitable O(3P) precursor (NO2 at 355 nm) above the surface of the liquid. This produces O(3P) atoms with a relatively broad, superthermal kinetic energy ... |
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| Two-Point Scalar Time-Series Measurements in Turbulent Partially Premixed Flames |
Feb-2009 |
24 pages |
| Authors:
Galen B King; Normand M Laurendeau; Michael W Renfro; PURDUE UNIV LAFAYETTE IN SCHOOL OF MECHANICAL ENGINEERING
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| The technique of Picosecond Time-Resolved Laser-Induced Fluorescence (PITL1F) was expanded to enable two-point hydroxyl (OH) series concentration time series measurements of turbulent jet flames. Measurements were obtained with two-point separation along the radial direction of the jet (delta r), i.e., the propagation direction of the horizontal laser beam, as well as axial two-point separations, i.e. along the axis of the jet, i.e., the z-direction. As the jet configuration is statistically ... |
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| Background Pressure Effects on Internal and Near-field Ion Velocity Distribution of the BHT-600 Hall Thruster (Preprint) |
24-Jun-2008 |
10 pages |
| Authors:
Michael R Nakles; Hargus; William A Jr; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Presented is a study of the effects of chamber background pressure on the ion axial velocity distribution within the discharge chamber and in the near-field of the Busek BHT-HD-600 xenon Hall effect thruster. Ion velocity distributions were measured along the acceleration channel centerline using laser-induced fluorescence of the 5d[4](sub 7/2)-6p[3](sub 5/2) xenon ion excited state transition. Measurements were taken at the lowest possible chamber background pressure and a pressure that ... |
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| Narrow-Linewidth Megahertz-Repetition-Rate Optical Parametric Oscillator for High-Speed Flow and Combustion Diagnostics |
01-Jan-2008 |
9 pages |
| Authors:
Naibo Jiang; Walter R Lempert; Gary L Switzer; Terrence R Meyer; James R Gord; OHIO STATE UNIV COLUMBUS DEPT OF MECHANICAL ENGINEERING AND CHEMISTRY
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| We demonstrate the ability to generate ultra-high-frequency sequences of broadly wavelength-tunable, high-intensity laser pulses using a custom-built optical parametric oscillator pumped by the third harmonic output of a burst-mode Nd:YAG laser. Burst sequences consisting of 6-10 pulses separated in time by 6-10 microsecond are obtained, with average total conversion efficiency from the 355 nm pump to the near-IR signal and idler wavelengths of approx. 33%. Typical individual pulse output energy ... |
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| Transient Plasma Induced Production of OH and its Effects on Ignition in Atmospheric CH4-AIR Quiescent Mixtures (Postprint) |
JAN 2008 |
12 pages |
| Authors:
Charles Cathey; Jeremy Cain; Hai Wang; Martin A. Gundersen; Michael Ryan; Campbell D. Carter; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| Transient plasma from a 60 kV, 70 ns pulse induced OH production in air and CH4/air quiescent mixtures inside a cylindrical chamber is analyzed. The resulting OH from the plasma discharge, ignition, and subsequent combustion is analyzed using planar laser induced fluorescence. A high-framing-rate camera was also used to image ignition and flame propagation in the chamber, providing spatial and temporal resolution over the entire combustion event. Results indicate OH ... |
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| Characterization of Iodine Quenching and Energy Transfer Rate Constants for Supersonic Flow Visualization Applications |
28 SEP 2007 |
28 pages |
| Authors:
Michael C. Heaven; EMORY UNIV ATLANTA GA DEPT OF CHEMISTRY
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| Planar laser induced fluorescence (PLIF) imaging is being used to study the fluid dynamics of supersonic gas mixing in the nozzle from a chemical oxygen iodine laser (COIL). PLIF images are recorded using laser excitation of the I(sub2) B-X transition. Data for the temperature dependences of the I(sub2)(B) quenching rate constants are needed for the quantitative interpretation of the PLIF data. A Mach 2.6 supersonic nozzle system has been used ... |
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| Energy Efficient Transient: Plasma Ignition: Physics and Technology |
30 AUG 2007 |
18 pages |
| Authors:
M. Gundersen; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF ELECTRICAL ENGINEERING AND ELECTROPHYSICS
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| The project has conducted basic studies of flame ignition collaborative studies of pulse detonation ignition, and preliminary studies of fundamental issues relevant to the application of transient plasma as an ignition source for Air Force high-speed aircraft applications. Preliminary basic science experiments have been conducted at the Air Force Research Laboratory (AFRL) using planar laser-induced fluorescence (PLIF) for investigation of radical production and ignition delay. Very strong enhancement of radical ... |
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| Ion Velocity Measurements within the Acceleration Channel of a Low Power Hall Thruster (Preprint) |
21 AUG 2007 |
28 pages |
| Authors:
Jr. Hargus William A.; Michael P. Nakles; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| This work presents axial ion velocity measurements within the acceleration channel of the Busek Co. Inc. BHT-200 200 W laboratory Hall thruster derived from laser-induced fluorescence measurements of the 5d[4]7/2-6p[3]5/2 xenon ion excited state transition. Acceleration channel centerline ion velocities were measured for one nominal and six related cases. These six cases were chosen to be representative of small variations of the applied propellant flow, magnetic field, and discharge charge ... |
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| Toxin Inhibition - Deconvolution Strategies and Assay Screening of Combinatorial Peptide Libraries |
AUG 2007 |
|
| Authors:
W. E. Lee; N. W. Chan; A. J. Marenco; G. J. Moore; D. MOORE; Lawrence J. Hayden; T. D. Laing; M. Gregory; D. C. Mah; M. G. Hamilton; DEFENCE RESEARCH AND DEVELOPMENT SUFFIELD (ALBERTA)
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 | Combinatorial peptide libraries offer an expedient source of structurally diverse molecules that could serve as lead compounds in the development of drug therapies to toxins. The libraries have typical structures of X1 - X2 - hinge - X3 - X4, where X1 through X4 are near-equimolar mixtures of twelve alpha-L-amino acids and hinge = gamma-aminobutyric acid. Screening of the libraries for inhibitory activity in assays for botulinum neurotoxins A and ... |
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| Advanced Laser and RF Plasma Sources and Diagnostics |
13-Jun-2007 |
19 pages |
| Authors:
John E Scharer; WISCONSIN UNIV-MADISON DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| We have purchased and have running state-of-the-art equipment that enhances our research capabilities for efficient laser initiation and radiofrequency sustainment of plasmas and diagnostics in air, as well as near microwave windows and on cathode surfaces as part of the MURI on Nano-physics of Electron Emission and Breakdown for High Power Microwaves. |
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| Deep Ultraviolet Laser Diode for UV-Resonance Enhanced Raman Identification of Biological Agents |
31 MAR 2007 |
215 pages |
| Authors:
William F. Hug; T. Moustakas; R. Treece; J. Smith; A. Bhattacharyya; R. Reid; J. Pankove; C. Brown; W. Nelson; PHOTON SYSTEMS COVINA CA
|
| This proposal addresses the need for deep UV semiconductor lasers for use in UV resonance enhanced Raman spectroscopic identification of biological agents. The proposed approach avoids the problems of p-doping and ohmic contacts by using subminiature direct electron injection excitation of an InAIGaN heterostructure. We have demonstrated strong stimulated emission at 274nm using this approach with measured linewidth reduction from 16nm to 4nm and five orders of magnitude non-linear increase ... |
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| Upstream Islands of Flame in Lifted-Jets Partially Premixed Combustion |
01-Jan-2007 |
10 pages |
| Authors:
K M Lyons; K A Watson; C D Carter; J M Donbar; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| Contemporary interest exists in understanding the roles of leading edge flow deflection, secondary jet instabilities and islands of ignited gases in permitting lifted flames to stabilize. To assess these issues, elements of the leading-edge of a lifted turbulent jet flame have been investigated using laser-imaging techniques. Images of flame position, morphology and dynamics are presented primarily from CH planar laser-induced fluorescence (CH-PLIF) measurements. In particular, evidence of flame islands, or ... |
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| PLIF Flow Visualization of a Supersonic Coil Nozzle (Postprint) |
16 OCT 2006 |
9 pages |
| Authors:
Carrie A. Noren; Gretchen Gothschopf; Ty Perschbacher; Timothy J. Madden; Gordon D. Hager; C. R. Truman; Peter V. Vorobieff; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
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| This paper describes Planar Laser-Induced Fluorescence (PLIF) flow visualization of a supersonic nozzle with supersonic injection. The nozzle simulates Chemical Oxygen Iodine Laser (COIL) flow conditions with non-reacting, cold flows, where the injected flow was seeded with iodine. A laser sheet near 565nm excited the iodine, and the fluorescence was imaged with a gated, CCD camera. Spanwise and steamwise images were taken, where the relative concentration of the injected to ... |
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| Decomposition of Energetic Materials from Excited Electronic States - RDX, HMX, Model Nitramines |
01 OCT 2006 |
12 pages |
| Authors:
Elliot R. Bernstein; COLORADO STATE UNIV FORT COLLINS DEPT OF CHEMISTRY
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| The energetic materials RDX, HMX, and CL-20 are studied in the gas phase by mass spectroscopy, optical wavelength resolved and time resolved spectroscopic techniques. We learn that NO is the first product of the dissociation of these molecules excited to their first electronic excited singlet states. The NO appears at less than 100 fs following the excitation pulse. A number of cyclic and non cyclic nitramine model systems are studied ... |
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| Independent Stage Control of a Cascade Injector (Postprint) |
OCT 2006 |
17 pages |
| Authors:
H. L. Meicenheimer; E. J. Gutmark; M. R. Gruber; D. R. Eklund; C. D. Carter; K.-Y. Hsu; CINCINNATI UNIV OH DEPT OF AEROSPACE ENGINEERING
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| An experimental investigation of a cascade injector was completed. The objective of this investigation was to determine whether the number of active stages in the cascade injector could be used to control penetration and mixing characteristics. The injector was tested at two overexpanded injection conditions in a Mach 3 crossflow. Shadowgraph and schlieren imaging, Mie scattering, Planar Laser Induced Fluorescence, and pressure profiling were the diagnostic techniques used to reveal ... |
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| Comparison of Hall Thruster Plume Expansion Model with Experimental Data (Preprint) |
JUL 2006 |
19 pages |
| Authors:
Carrie S. Niemela; Shannon Y. Cheng; Lubos Brieda; Michael Nakles; Jared Ekholm; Jr. Hargus William; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Numerical modeling of the expansion of electric thruster plumes provides direct means for predicting spacecraft surface contamination and erosion due to plume ions. A software package named COLISEUM that is capable of self-consistently modeling plasma propagation and interactions with arbitrary 3-D surfaces is being developed by a national team of researchers. Despite much research and development in modeling plume expansion, it is necessary to continuously validate these codes using laboratory ... |
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| Comparison of Numerical and Experimental Near-Field Plasma Properties of the BHT-200-X3 Hall Thruster (Preprint) |
JUL 2006 |
25 pages |
| Authors:
Garrett D. Reed; William A. Hargus; Douglas B. VanGilder; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Near-field ion velocity distributions of a BusekBHT-200-X3 xenon Hall thruster obtained through numerical simulation are compared with laser-induced fluorescence measurements taken for one nominal operating condition. The numerical code Hybrid-PIC Hall, a 2D hybrid particle-in-cell model, is used to simulate an axisymmetric cross section of the plasma acceleration zone. A set of nine HP Hall simulations are run using three different cathode positions and Bohm electron mobility coefficients to study ... |
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| Advanced Nozzle Concepts for the Chemical Oxygen-Iodine Laser (COIL) |
MAR 2006 |
84 pages |
| Authors:
Valeri D. Nikolaev; RUSSIAN ACADEMY OF SCIENCES MOSCOW (RUSSIA) LEBEDEV INST
|
| This report results from a contract tasking P. N. Lebedev Physical Institute as follows: Iodine lasers offer the possibility of producing high average powers at a wavelength compatible with conventional fiber optic delivery systems, making them attractive for industrial applications. The planned experimental and theoretical investigations are aimed to a great extent for further understanding of physical processes taking place during mixing of gaseous components and laser active medium preparation. ... |
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| Aero-Optical Wavefront Propagation and Refractive Fluid Interfaces in Large-Reynolds-Number Compressible Turbulent Flows |
31 DEC 2005 |
45 pages |
| Authors:
Haris J. Catrakis; Rhett Jefferies; CALIFORNIA UNIV IRVINE DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| The physical behavior of refractive fluid interfaces in turbulent compressible separated shear layers and the resulting structure of the aero-optical wavefronts have been investigated using new experimental studies and physical modeling. The experiments utilize the new AFOSR/UCI variable-pressure facility which generates large Reynolds number flows with elevated pressures in the test section crucial for direct imaging of the refractive field and interfaces. Direct, non-intrusive, and non-integrated imaging of the refractive ... |
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| Statistical Interpretation of Scalar Time-Series Measurements in Turbulent Partially Premixed Flames |
14 DEC 2005 |
26 pages |
| Authors:
PURDUE UNIV LAFAYETTE IN SCHOOL OF MECHANICAL ENGINEERING
|
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| Experimental Study and Numerical Modeling of Gas Flow in Microchannels and Micronozzles |
DEC 2005 |
110 pages |
| Authors:
C. X. Lin; Peter V. Skudarnov; FLORIDA INTERNATIONAL UNIV MIAMI HEMISPHERIC CENTER FOR ENVIRONMENTAL TECHNOLOGY
|
| During the course of this research effort gas flows in microchannels and micronozzles were studied both experimentally and numerically. For the experimental study a flow visualization system was built and used to Study gas flows in microscale. Gas velocity measurements in microscope were conducted using both Laser Induced Fluorescence technique in conjunction with Image Correlation Velocimetry and Molecular Tagging Velocimetry technique. For the numerical study three different approaches were utilized. ... |
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| Hall Thruster With an External Acceleration Zone |
14 SEP 2005 |
8 pages |
| Authors:
Nicolas Gascon; Ronald L. Corey; Mark A. Cappelli; William Hargus; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| This work presents the general operation and the near exit plane ion velocity field of the Stanford Linear Hall Thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and cross-field (along the electron Hall current ... |
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| Experimental Investigation of the Interaction of Electrothermal Plasmas with Solid Propellants |
31 JUL 2005 |
37 pages |
| Authors:
Michael D. Ryan; Noel T. Clemens; Philip L. Varghese; TEXAS UNIV AT AUSTIN OFFICE OF SPONSORED PROJECTS
|
| The work presented is part of continuing experimental study of the ignition of solid propellants by electrothermal capillary plasmas. Experiments have been made to characterize further the pulsed plasma expanding into room air and to investigate ignition of JA-2 propellant in a closed chamber. A particular emphasis is placed on discussing the difficulties in conducting diagnostics in this challenging environment. Heat flux measurements were made with a heat flux sensor ... |
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| Oil Slick Detection and Characterization by Satellite and Airborne Sensors: Experimental Results with SAR, Hyperspectral and Lidar Data |
25 JUL 2005 |
|
| Authors:
M. Lennon; N. Thomas; V. Mariette; S. Babichenko; G. Mercier; SAS ACTIMAR BREST (FRANCE)
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| Efficient observation means are required for regional-scale detection of oil slicks at sea, as well as for local-scale quantitative mapping in order to support operational fight and recovering operations, including reliable choice and guidance of maritime and airborne fighting means. An efficient oil slick detection algorithm based on a multiscale approach is proposed for operational regional-scale detection from satellite SAR images. The potential of combining airborne passive hyperspectral imagery and ... |
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| Mixing Effects of Pylon-Aided Fuel Injection Located Upstream of a Flameholding Cavity in Supersonic Flow (Postprint) |
JUL 2005 |
24 pages |
| Authors:
Daniel R. Montes; Paul I. King; Mark R. Gruber; Campbell D. Carter; Kuang-Yu Hsu; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| An investigation into the non-reacting flow associated with the pylon-aided gaseous fuel injection upstream of a flame holding cavity is described. Characteristics of penetration and mixing were measured in a Mach 2 freestream environment. The downstream combustion cavity had an LID of 4.7 and an aft ramp angle of 22.5 degrees. A circular injection port was placed upstream of the cavity, and a series of three pylons (medium, tall, wide ... |
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| Ion Velocity Measurements in a Linear Hall Thruster |
JUN 2005 |
7 pages |
| Authors:
Nicolas Gascon; Mark A. Cappelli; William A. Hargus Jr; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| This work presents the general operation and the near exit plane velocity field of the Stanford Linear Hall thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and transverse (along the electron Hall current direction) ... |
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| Optical Boron Nitride Insulator Erosion Characterization of a 200 W Xenon Hall Thruster |
MAY 2005 |
11 pages |
| Authors:
William A. Hargus Jr; Joshua Strafaccia; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| Vacuum ultraviolet emission (137.9 nm) of boron neutrals sputtered from a 200 W xenon Hall thruster boron nitride insulator is evaluated as a diagnostic for real-time evaluation of thruster insulator erosion. Three Hall thruster plasma control variables are examined: ion energy (discharge potential), ion flux (propellant flow), and plasma conductivity (magnetic field strength). The boron emission, and hence the insulator erosion rate, varies linearly with ion energy and ion flux. ... |
|
| Hydrocarbon-Fueled Scramjet Research at Hypersonic Mach Numbers |
31 MAR 2005 |
138 pages |
| Authors:
Frank Houwing; AUSTRALIAN NATIONAL UNIV CANBERRA DEPTOF PHYSICS
|
| Planar laser-induced fluorescence (PLIF) of OH and wall-pressure measurements have been used to investigate the combustion in a cavity flame-holder scramjet combuster. |
|
| Mixing Effects of Pylon-Aided Fuel Injection Located Upstream of a Flameholding Cavity in Supersonic Flow |
MAR 2005 |
233 pages |
| Authors:
Daniel R. Montes; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| The Air Force Research Lab (AFRL), Propulsion Directorate, Wright- Patterson Air Force Base, Ohio is conducting ongoing research into propulsive efficiency in supersonic ramjet (scramjet) technology. One current focus of this research is the usefulness of flameholding cavities implemented in the supersonic hydrocarbon-fueled combustion chamber. Because good mixing and proper cavity-core interaction lead to more efficient combustion, methods of optimizing fuel/air mixing both within and upstream the cavity are investigated. ... |
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| The Single Cell Proteome Project - Cell-Cycle Dependent Protein Expression in Breast Cancer Cell Lines |
JAN 2005 |
28 pages |
| Authors:
Norman J. Dovichi; WASHINGTON UNIV SEATTLE
|
| Protein fingerprints of single MCF7 breast cancer cells were mapped using both one-dimensional and two-dimensional capillary electrophoresis (CE). While one-dimensional CE can resolve dozens of proteins, two-dimensional CE has the potential to resolve hundreds or thousands of proteins with broad dynamic range. Cellular proteins are labeled on column by coupling lysine residues with the fluorogenic reagent 3-(2-furoyl)quinoline-2 carboxaldehyde. Labeled proteins are detected by laser-induced fluorescence in a sheath flow cuvette. ... |
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| Acquisition of Time-Varying Participating Media |
2005 |
5 pages |
| Authors:
Tim Hawkins; Per Einarsson; Paul Debevec; UNIVERSITY OF SOUTHERN CALIFORNIA MARINA DEL REY CA INST FOR CREATIVE TECHNOLOGIES
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| We present a technique for capturing time-varying volumetric data of participating media. A laser sheet is swept repeatedly through the volume, and the scattered light is imaged using a high-speed camera. Each sweep of the laser provides a near-simultaneous volume of density values. We demonstrate rendered animations under changing viewpoint and illumination, making use of measured values for the scattering phase function and albedo. |
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| Rapid Protein Separations in Microfluidic Devices |
DEC 2004 |
6 pages |
| Authors:
Z. H. Fan; Champak Das; Zheng Xia; Alexander V. Stoyanov; Carl K. Fredrickson; FLORIDA UNIV GAINESVILLE MECHANICAL AND AEROSPACE ENGINEERING
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| This paper describes fabrication of glass and plastic microfluidic devices for protein separations. Although the long-term goal is to develop a microfluidic device for two-dimensional gel electrophoresis, this paper focuses on the first dimension-isoelectric focusing (IEF). A laser-induced fluorescence (LIF) imaging system has been built for imaging an entire channel in an IEF device. The whole-channel imaging eliminates the need to migrate focused protein bands, which is required if a ... |
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| Propagation of High-Power, Femtosecond Laser Radiation through the Atmosphere |
19 OCT 2004 |
56 pages |
| Authors:
Alexander Zemlyanov; EUROPEAN OFFICE OF AEROSPACE RESEARCH AND DEVELOPMENT FPO NEW YORK 09510
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| This report results from a contract tasking the Institute of Atmospheric Optics, Siberian Branch, as follows: the contractor will investigate theoretically the interaction between femtosecond propagation effects and atmospheric turbulence, supercontinuum emission (spectral broadening), nonlinear scattering by atmospheric aerosols, and theoretical upper and lower limits for nonlinear propagation effects. The specific project objectives are as follows: (1) The theoretical study of powerful femtosecond laser pulse filamentation in the turbulent atmosphere; ... |
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| Impulse Pendulum with Adjustable Pivot Point for Measuring Coupling Coefficient |
OCT 2004 |
8 pages |
| Authors:
John S. Harchanko; Franklin B. Mead Jr.; C. W. Larson; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| An impulse pendulum with significantly increased sensitivity compared to its predecessor is described. The problems associated with its predecessor are discussed and other pendulum designs are also presented. The design approach for the new pendulum is then presented along with the current mechanical design and photographs of the finished pendulum. The pendulum's performance is presented compared to its predecessor. Finally, other embodiments of the approach are presented. |
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| Long-Lived, Energetic States of Small Molecules: Spectroscopy, Pattern Recognition, and Formation/Destruction Mechanisms |
30 JUN 2004 |
17 pages |
| Authors:
Robert W. Field; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY
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| The formation, deactivation, and detection mechanisms of atoms and molecules in metastable electronically excited states are, in general, ill characterized. Yet the chemical and photophysical properties of such states are relevant to Air Force Missions in communication, upper atmosphere modeling, and high-speed vehicle tracking, and identification. The capabilities of a multispectral molecular beam apparatus have been demonstrated on the electronic spectrum of acetylene in the energy region of the first ... |
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| Laser Diagnostics for Reacting Flows |
25 JUN 2004 |
79 pages |
| Authors:
Ronald K. Hanson; STANFORD UNIV CA
|
| Advanced optical diagnostic techniques relevant to propulsion were investigated. The techniques studied were based on laser spectroscopy, with emphasis on spectrally-resolved absorption and laser-induced fluorescence (LIF) . Spectrally narrow, continuous wave (cw) lasers allowed innovative diagnostics based on spectral line shapes, while pulsed lasers provided intense bursts of photons needed for techniques based on LIF. Accomplishments of note included: studies of fundamental ketone in Support of PLIF imaging diagnostics for ... |
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Reports by Keyword(s)
LASER INDUCED FLUORESCENCE
