| Quantum Yield Enhancement of Cd/Se Colloidal Quantum Dots by Variation of Surface Ligands |
Jan 2013 |
18 pages |
| Authors:
David Gudeman; Witold Palosz; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
 | Colloidal cadmium/selenium (Cd/Se) quantum dots (QDs) were synthesized with two different sets of ligands. The first used simple components, octadecene (ODE), which serves both as a solvent and a ligand, and oleic acid, which also serves as a ligand. The second used more complex ligands, octadecylphosphonic acid, and oleyamine. Transient samples have been collected during the course of each synthesis. Then the particle diameter and quantum yield (QY) of the ... |
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| Near Field Imaging for the Characterization of Diffusion Length and Waveguiding in Zinc Oxide Nanowires |
Jun 2012 |
101 pages |
| Authors:
Anree G Little; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| novel technique of near field imaging has been advanced and used to measure free carrier diffusion length and study optical waveguiding in ZnO nanowires. The technique employs a near field scanning optical microscope (NSOM) and atomic force microscope (AFM) to optically and spatially map cathodoluminescence generated by a scanning electron microscope (SEM). The technique has been advanced from previous work on nanowires by the use of a higher resolution SEM ... |
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| Spray Statistics and the Impact of Geometry in Gas-Centered Swirl Coaxial Injectors |
May 2012 |
17 pages |
| Authors:
Malissa D Lightfoot; Alan L Kastengren; S A Schumaker; Stephen A Danczyk; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIR
|
| Optically dense sprays are often encountered in propulsion applications such as rocket engines. The density of these sprays prevents measurement of droplet diameters and quantitative assessment of spray quality. The lack of quantitative data hinders the development of design criteria and complicates the formation of a fundamental understanding of the impact changes to injector geometry make in an engine's performance. While recent strides have been made in attaining qualitative data ... |
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| Flux Pinning Enhancement in YBa2Cu3O7-x Films for Coated Conductor Applications (Postprint) |
Feb 2012 |
25 pages |
| Authors:
C V Varanasi; P N Barnes; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| It is shown that YBCO films with BaSnO3 (BSO) nano-additions, made with either a sectored target or with a premixed target using pulsed-laser deposition (PLD), have a much greater improvement in Jc at the higher fields with an H//c orientation. More than two orders of magnitude improvement in Jc was observed as compared to undoped or similarly processed Y2BaCuO5 (Y211) doped samples at magnetic fields higher than 5 T. The ... |
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| Optical Super-Resolution by High-Index Liquid-Immersed Microspheres |
Jan 2012 |
6 pages |
| Authors:
Arash Darafsheh; Gary F Walsh; Luca Dal Negro; Vasily N Astratov; NORTH CAROLINA UNIV AT CHARLOTTE
|
| It is experimentally shown that barium titanate glass microspheres with diameters (D) in the range 2 220 micrometer and with high refractive index (n1.9 2.1) can be used for super-resolution imaging of liquid-immersed nanostructures. Using micron-scale microspheres, we demonstrate an ability to discern the shape of a pattern with a minimum feature size of lambda/7, where lambda is the illumination wavelength. For spheres with D50 micrometer, the discernible feature sizes ... |
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| Deceleration of Projectiles in Sand |
Jan 2012 |
5 pages |
| Authors:
Stephan Bless; William Cooper; Keiko Watanabe; Robert Peden; AIR FORCE RESEARCH LAB EGLIN AFB FL
|
| Penetration of projectiles was measured for hemispherical and conical nose shapes penetrating granular media. Targets were beds of Ottawa sand and Eglin sand. Projectiles were rigid metals. Experimental parameters that were varied included velocity (from 300 to 600 m/s), nose shape, sand density, and scale (from 5 mm to 20 mm). Strong evidence for scale effects is found: 5 mm diameter projectiles are less effective penetrators than 12.5, 15, or ... |
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| Novel Bonding Process for CBW Protective Electrospun Fabric Laminates Phase 2 |
Dec 2011 |
95 pages |
| Authors:
Michael A Costolo; John D Lennhoff; Jeffrey W Bacon; PHYSICAL SCIENCES INC ANDOVER MA
|
| Report developed under Small Business Innovation Research contract. Electrospun membranes for CBW protective fabric were modeled, developed, and tested. Theoretical models for gas permeation, as well as filtration efficiency, were developed as functions of fiber diameter. The effects of varying the process variables on the fiber morphology were also explored. The mechanical properties of the electrospun nonwoven fabrics were tested, as well as the filtration efficiency of electrospun Estane membranes. ... |
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| Magnetic Resonance Characterization of Axonal Response to Spinal Cord Injury |
Oct 2011 |
29 pages |
| Authors:
David Hackney; BETH ISRAEL DEACONESS MEDICAL CENTER BOSTON MA
|
| During the first year we pursued studies of q-space imaging (QSI) of the spinal cord and myelin imaging. The QSI studies extended our previous work establishing our ability to define the distribution of axon fiber diameters using this noninvasive approach. This work was presented at the Annual Meeting of the International Society of Magnetic Resonance in Medicine in Montreal, May, 2011. In addition, we made great progress with an ultra-short ... |
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| Operational Characteristics of a Rotating Detonation Engine Using Hydrogen and Air |
JUN 2011 |
105 pages |
| Authors:
Rachel M. Russo; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Rotating detonation engines (RDE) are pressure gain combustion engines that have the potential for greater efficiency than traditional, constant pressure, deflagration engines. RDEs are smaller and mechanically simpler than pulsed detonation engines. A small diameter (3 in) engine was successfully run on hydrogen and air. Most of the tests were conducted using air with a slightly lower diluents percentage (77% nitrogen as opposed to 79% nitrogen). These tests provided the ... |
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| Insect Optic Glomeruli-Exploration of a Universal Circuit for Sensorimotor Processing |
25 Jan 2011 |
11 pages |
| Authors:
Nicholas J Strausfeld; Charles Higgins; ARIZONA UNIV TUCSON
|
| Research during the reporting period focused on exploration of miniaturization of brains and signaling by visual inter-neurons encoding information about features of the visual surround. Research focused on the brain of the genetically tractable Drosophila fly, using genetic markers to locate neurons and record from these using patch clamp. The research has discovered a novel attribute of miniaturized brains; namely that of analogue signaling and information pooling to overcome inherent ... |
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| Transfer of CVD-Grown Monolayer Graphene onto Arbitrary Substrates |
Jan 2011 |
10 pages |
| Authors:
Ji W Suk; Alexander Kitt; Carl W Magnuson; Yufeng Hao; Samir Ahmed; Jinho An; Anna K Swan; Bennett B Goldberg; Rodney S Ruoff; TEXAS UNIV AT AUSTIN DEPT OF MECHANICAL ENGINEERING
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| Reproducible dry and wet transfer techniques were developed to improve the transfer of large-area monolayer graphene grown on copper foils by chemical vapor deposition (CVD). The techniques reported here allow transfer onto three different classes of substrates substrates covered with shallow depressions, perforated substrates, and flat substrates. A novel dry transfer technique was used to make graphene-sealed microchambers without trapping liquid inside. The dry transfer technique utilizes a polydimethylsiloxane frame ... |
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| Multi-Epoch Mid-Infrared Interferometric Observations of the Oxygen-rich Mira Variable Star RR Aql with the VLTI/MIDI Instrument |
Jan 2011 |
6 pages |
| Authors:
I Karovicova; M Wittkowski; D A Boboltz; E Fossat; K Ohnaka; M Scholz; NAVAL OBSERVATORY WASHINGTON DC
|
| This work is part of an on-going program of multi-epoch simultaneous observations of a sample of four evolved stars - RR Aql, GX Mon, S Ori, and AH Sco - using the VLTI and VLBA facilities. Different pulsating layers and their relative positions are monitored across phases and cycles. Here, we present mid-infrared interferometric observations of the oxygen-rich Mira variable RR Aql at 13 epochs covering 4 pulsation cycles with ... |
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| An Experimental Investigation Studying the Influence of Dimples on a Film Cooled Turbine Blade Leading Edge |
Mar-2009 |
171 pages |
| Authors:
Paul G Frisinger; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| An investigation was conducted to examine the effect of a row of cylindrical surface dimples in reducing the heat load on a turbine blade leading edge model. The models consisted of a foam cylindrical leading edge with a flat afterbody fabricated from Plexiglass. A single coolant hole was located 21.5? from the leading edge, angled 20? to the surface and 90? from the streamwise direction. The leading edge diameter to ... |
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| Rear-Wheel Steering for Aircraft Rescue and Firefighting Vehicles; Test and Evaluation |
01-Sep-2008 |
29 pages |
| Authors:
Keith Bagot; Jennifer L Kalberer; Michael J McDonald; Carr; Virgil J Jr; FEDERAL AVIATION ADMINISTRATION ATLANTIC CITY NJ AIRPORT AND AIRCRAFT SAFETY RESEARCH AND DEVELOPMENT
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| The objective of this effort was to evaluate the performance of rear wheel steering (RWS) features of the Federal Aviation Agency (FAA) Striker Fire Truck on tread wear, tire deflection, and turning diameter. The RWS feature was designed to improve vehicle maneuverability, narrow the turning diameter and reduce drag on the tires. Due to programmatic limitations only exploratory validation of the rear-wheel steering was accomplished, therefore no statistical inference from ... |
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| Mass Remaining During Evaporation of Sessile Drop |
01-Sep-2008 |
35 pages |
| Authors:
James E Danberg; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ABINGDON MD
|
| A theory to predict the evaporation rate of HD (mustard agent) for the special case of a glass substrate has been developed. This is an important reference case for the wind tunnel and field test measurements of the HD evaporation rate. The HD drop is treated as a spherical segment with a constant base diameter characterized by the variation of the droplet shape factor (height to base diameter) or contact ... |
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| A Wide Area Bipolar Cascade Resonant Cavity Light Emitting Diode for a Hybrid Range-Intensity Sensor |
19 JUN 2008 |
195 pages |
| Authors:
Reginald J. Turner; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This dissertation focused on the development of an illuminator for the HRIS. This illuminator enables faster image rendering and reduces the potential of errors in return signal data, that could be generated from extremely rough terrain. Four major achievements resulted from this work, which advance the field of 3-D image acquisition. The first is that the TJ is an effective current spreading layer for LEDs with mesa width up to ... |
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| The Effect of Diameter on Dynamic Seabed Penetration |
02-May-2008 |
137 pages |
| Authors:
Catherine M Ortman; NAVAL ACADEMY ANNAPOLIS MD
|
| An accurate estimate of the undrained shear strength of seabed sediments is critical to the design of foundations and anchors of offshore structures. Naval mine warfare and undersea salvage also depend on the prediction of seafloor embedment depth, which is primarily a function of sediment strength. Direct measurement of in-situ sediment strengths in the offshore environment is often difficult using conventional methods, especially where depths prohibit the use of divers. ... |
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| New Synthesis for Lanthanum Hexaboride Nanocrystals |
26 Mar 2008 |
4 pages |
| Authors:
Lisa Pfefferie; YALE UNIV NEW HAVEN CT DEPT OF CHEMICAL ENGINEERING
|
| Although lanthanum hexaboride has been used for many years as a cathode material, new applications exploiting its unusual electron emission properties are now being investigated. Nanocrystalline LaB6 materials have been predicted to provide important advantages for IR absorbers as well as for nanoelectronics in general because of their low work function. Lanthanum hexaboride is usually made by mixing La and B with Al in a furnace at 1500K. The molten ... |
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| Electronic Transport Control of Bi Nanowires |
07 SEP 2007 |
24 pages |
| Authors:
Tito E. Huber; HOWARD UNIV WASHINGTON DC
|
| Theoretical models of the effect of quantum confinement in nanowire arrays show that thermoelectric cooler efficiency can be enhanced several-fold using this strategy. Previous experimental studies of well characterized samples failed to show an enhancement of the thermopower, but the reason for this failure was not identified. We show that bismuth nanowires have, in addition to bulk electrons and holes, a third type of charge carriers (surface charges). The effect ... |
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| Determining Surface Combatant Characteristics Requirements Through A Mission Effectiveness Analysis Framework |
SEP 2007 |
75 pages |
| Authors:
Jeffrey A. Koleser; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Ship performance characteristics, such as max-sustained speed, acceleration, and maneuverability are generally pre-determined as a platform requirement based on precedents. However, these pre-determined performance characteristics have far reaching impacts on the size, logistics, manning, and cost of the ship platform. Instead of designing to pre-defined platform performance requirements, ship performance characteristics should be determined based on fulfilling mission objectives. This research evaluates the viability to effectively determine if the ship ... |
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| Combustion of Nanoscale Al/MoO3 Thermite in Microchannels |
Aug 2007 |
8 pages |
| Authors:
S F Son; B W Asay; T J Foley; R A Yetter; M H Wu; G A Risha; LOS ALAMOS NATIONAL LAB NM
|
| Microscale combustion is of interest in small-volume energy-demanding systems, such as power supplies, actuation, ignition, and propulsion. Energetic materials can have high burning rates that make these materials advantageous, especially for microscale applications in which the rate of energy release is important or in which air is not available as an oxidizer. In this study we examine the combustion of mixtures of nanoscale aluminum with molybdenum trioxide in microscale channels. ... |
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| Application of Nanofiber Technology to Nonwoven Thermal Insulation |
NOV 2006 |
9 pages |
| Authors:
Phil Gibson; Calvin Lee; ARMY SOLDIER SYSTEMS COMMAND NATICK MA
|
| Nanofiber technology (fiber diameter less than 1 micrometer) is under development for future Army lightweight protective clothing systems. Nanofiber applications for ballistic and chemical/biological protection are being actively investigated, but the thermal properties of nanofibers and their potential protection against cold environments are relatively unknown. Previous studies have shown that radiative heat transfer in fibrous battings is minimized at fiber diameters between 5 and 10 micrometers. However, the radiative heat ... |
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| High-Efficiency Helical Coil Electromagnetic Launcher |
31 AUG 2006 |
37 pages |
| Authors:
Thomas G. Engel; William C. Nunnally; John M. Gahl; MISSOURI UNIV-COLUMBIA DEPT OF ELECTRICAL ENGINEERING
|
| Technical progress during the reporting period includes the development of new theory for electromagnetic launcher efficiency which is applicable to all constant inductance gradient launcher geometries. This theory also develops methods to predict the performance of different geometry electromagnetic launchers and compare them to each other. A theoretical analysis is also presented to design a helical electromagnetic launcher for a specific volt- amp characteristic. Experimentally measured performance is reported for ... |
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| Canister Design for Deep Borehole Disposal of Nuclear Waste |
MAY 2006 |
126 pages |
| Authors:
Christopher I. Hoag; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF NUCLEAR ENGINEERING
|
| The objective of this thesis was to design a canister for the disposal of spent nuclear fuel and other high-level waste in deep borehole repositories using currently available and proven oil, gas, and geothermal drilling technology. The canister is suitable for disposal of various waste forms, such as fuel assemblies and vitrified waste. The design addresses real and perceived hazards of transporting and placing high-level waste, in the form of ... |
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| Effect of Substrate Thickness on Exploding Films |
May-2006 |
5 pages |
| Authors:
J Zirnheld; S Olabisi; P Strzempka; A Halstead; B Urbanczyk; H Moore; STATE UNIV OF NEW YORK AT BUFFALO ENERGY SYSTEMS INST
|
| The exploding wire phenomenon is well researched due to its vast and practical applications which include, but are not limited to, shock wave generation, pulsed power, Z pinch physics, plasma ignition, fuses, and fusing applications. However, the focus of this research is on a surrogate for exploding wires. In this research, metallized capacitor grade-polypropylene film was used as an alternative for the traditional wire of a uniform diameter. The films ... |
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| Effects of Diameter And Cross-Sectional Partitioning on Active Noise Control in Round Ducts |
14 APR 2006 |
87 pages |
| Authors:
Jeremy M. Slagley; WEST VIRGINIA UNIV MORGANTOWN COLL OF ENGINEERING AND MINERAL RESOURCES
|
| Active noise control (ANC) is particularly useful in hard-walled ducts where plane waves propagate. Higher order mode waves are much more difficult to control. Basic acoustic principles dictate that the cut-on frequency at which higher order modes will first begin to eclipse simple plane waves in a duct will be determined by the cross-sectional diameter of the duct. The lowest frequency for higher order modes will increase as diameter decreases. ... |
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| Early Type Stars as Calibrators for Ground-Based Interferometry |
2006 |
8 pages |
| Authors:
Jinmi Yoon; Deane M. Peterson; Thomas Amstrong; James H. Clark III; Charmaine Gilbreath; Thomas Pauls; Henrique R. Schmitt; STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF PHYSICS AND ASTRONOMY
|
| Visibility measurements with Michelson interferometers, particularly the measurement of fringe contrast, are affected by various atmospheric and instrumental effects, all of which reduce the measured contrast. To compensate for this, stars with known or predictable diameters (calibrators) are observed so that the overall reduction in the visibility can be measured. Objects with the smallest possible diameters are preferred as calibrators, since the predicted visibilities become less sensitive to any uncertainties. ... |
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| Study of Quantum Point Contact via Low Temperature Scanning Gate Microscopy |
2006 |
5 pages |
| Authors:
N. Aoki; A. Burke; C. R. da Cunha; R. Akis; D. K. Ferry; Y. Ochiai; ARIZONA STATE UNIV TEMPE DEPT OF ELECTRICAL ENGINEERING
|
| Two types of quantum point contacts have been studied by low temperature scanning gate microscopy. In addition to the usual bright spot, which corresponds to a large conductance change at the constriction, ring structures are observed near the center of the quantum point contact. The ring diameter shrinks with increasing base conductance when the side gate voltage is changed. The rings are thought to relate to the observation of impurity ... |
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| Ablation Study in a Capillary Sustained Discharge |
2006 |
11 pages |
| Authors:
Michael Keidar; Iain D. Boyd; Anthony Williams; Richard Beyer; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
|
| Electrothermal-chemical (ETC) ignition systems have been demonstrated in gun systems to provide desirable characteristics including reproducible shorter ignition delays. The optimum combination of capillary tube and fuse wire properties has not been identified yet. We present a combined theoretical and experimental study of the capillary discharge with an aim to develop a capillary plasma source with efficient energy conversion. The major emphasis in the present capillary discharge model is the ... |
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| Distribution Models for Optical Scintillation Due to Atmospheric Turbulence |
12 DEC 2005 |
|
| Authors:
R. R. Parenti; R. J. Sasiela; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
 | Traditional analyses ot optical scintillation usually invoke the Rytov approximation and the associated assumptions regarding weak phase perturbations throughout the propagation channel. Associated with that approach is the prediction that the statistics of scintillation will be log-normal. This report, which uses the Fresnel propagation function as a basis, challenges many of the standard descriptions of far-field irradiance fluctiiations. A key finding of this study is the importance of the ratio ... |
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| Ultra-High-Q Microcavity Operation in H2O and D2O |
07 OCT 2005 |
4 pages |
| Authors:
A. M. Armani; D. K. Armani; B. Min; K. J. Vahala; S. M. Spillane; CALIFORNIA INST OF TECH PASADENA DEPT OF APPLIED PHYSICS
|
| Optical microcavities provide a possible method for boosting the detection sensitivity of biomolecules. Silica-based microcavities are important because they are readily functionalized, which enables unlabeled detection. While silica resonators have been characterized in air, nearly all molecular detections are performed in solution. Therefore, it is important to determine their performance limits in an aqueous environment. In this letter, planar microtoroid resonators are used to measure the relationship between quality factor ... |
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| Shaped Charge Jet Flash Radiograph Digitization |
SEP 2005 |
44 pages |
| Authors:
James D. Pham; Ernest L. Baker; Stanley DeFisher; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ ENERGETICS WARHEADS ENVIRO TECH
|
| The flash radiograph digitization of shaped charge jets provides warhead designers with the data required for empirically based models, as well as the jet characterization used for comparison with high rate continuum modeling. Reduced digitization results include jet tip velocity, jet accumulated length, accumulated mass, accumulated energy, break up time, maximum and average jet diameters, and the ductility factor (0). This Computer program provides a systematic method of characterizing a ... |
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| Surface Piercing Propeller Performance |
SEP 2005 |
81 pages |
| Authors:
Derek Peterson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MECHANICAL AND ASTRONAUTICAL ENGINEERING
|
| This thesis addresses possible improvements in the efficiency (thrust) of surface piercing propellers; in particular with respect to the angle of the propeller shaft came to mind. Preliminary calculations based on the basic pitch/diameter geometry suggest that about 3-5% efficiency is lost if the shaft is parallel to the flow, compared to skewed a few degrees in the "paddlewheel" direction at certain speeds. More accurate calculations based on the lift ... |
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| Joint VLBA/VLTI Observations of the Mira Variable S Orionis |
10 JAN 2005 |
10 pages |
| Authors:
David A. Boboltz; Markus Wittkowski; NAVAL OBSERVATORY WASHINGTON DC
|
| We present the first coordinated Very Long Baseline Array (VLBA) / very Large Telescope Interferometer (VLTI ) measurements of the stellar diameter and circumstellar atmosphere of a Mira variable star. Observations of the v=1, J=1-0 (43.1 GHz) and v=2, J=1-0 (42.8 GHz) SiO maser emission toward the Mira variable S Ori were conducted using the VLBA. Coordinated near-infrared K-band measurements of the stellar diameter were performed using VLTI-VINCI closely spaced ... |
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| Use of Small-Diameter Bladder Pumps in Direct-Push Ground Water Monitoring Wells at the CRREL Site |
DEC 2004 |
21 pages |
| Authors:
Louise V. Parker; John W. Govoni; Martin H. Stutz; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| Several different small-diameter (1/2-inch and 3/4-inch) bladder pumps (from different manufacturers) were tested in 1/2-inch and 3/4-inch direct-push (DP) monitoring wells at the CRREL site in Hanover, New Hampshire. Obtaining a sample at this site has been challenging because the depth to ground water is over 100 feet and thus substantial lift is required to bring the water to the surface. Although the different brands of pumps fit into the ... |
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| BioSim (trademark) BG Non-Biological Aerosol Simulant |
17 NOV 2004 |
11 pages |
| Authors:
David S. Alburty; Kelly L. Brown; Jennifer L. Dannehl; Andrew E. Page; Freeman Swank; Richard R. Thomas; MIDWEST RESEARCH INST KANSAS CITY MO
|
| A non-biological simulants has been developed for use as a safe effective alternative to Bacillus globigii (Bg). The simulant consists of one-micron polystyrene carrier beads with an aerodynamic diameter similar to anthrax spores, with total genomic Bg DNA attached to the surface. The DNA attachment to the bead is robust enough to withstand aerosolization and collection processes, yet reacts in a PCR-based detector using existing analytical protocols. BioSim(TradeMark) Bg can ... |
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| Very Low Volatile Organic Compound Spray Application Process for Iron Filled Elastomeric Coatings |
02 APR 2004 |
13 pages |
| Authors:
Yudaya Sivathanu; Paul Sojka; Wongyo Kim; EN'URGA INC WEST LAFAYETTE IN
|
| This Small Business Innovation Research Phase 1 project evaluated the feasibility of a new method for spraying high viscosity coatings. This new method of forming sprays uses very little VOC solvents, and has two distinguishing features: (1) The application of effervescent atomization for producing droplets independent of the fluid viscosity, and (2) a perforated aerator tube insert to control both the Sauter mean diameter (SMD, or D32) and the distribution ... |
|
| Aligned Single-Walled Carbon Nanotube Synthesis for Device Design |
29 FEB 2004 |
54 pages |
| Authors:
L. D. Pfefferle; G. L. Haller; Mark Reed; YALE UNIV NEW HAVEN CT
|
| This project was highly successful demonstrating control of carbon nanotube diameter through control of the synthesis process. Mean tube diameter can be preselected from 0.5 to 0.9nm. A sample predominantly semiconducting with two main tubes (7,5 and 8,3), and a sample of smaller (0.5-0.6nm) and mainly metallic tubes were produced. The process also laid the ground for production of the first pure boron nanotubes. In our SWNT synthesis experiments using ... |
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| Fringe Fitting for Coherent Integrations with the NPOI |
2004 |
13 pages |
| Authors:
A. M. Jorgensen; D. Mozurkewich; T. Armstrong; R. Hindsley; T. Pauls; C. Gilbreath; S. Restaino; NAVAL RESEARCH LAB WASHINGTON DC
|
| We have developed a method for performing long coherent integrations with the Navy Prototype Optical Interferometer (NPOI), which is based on fitting a model fringe pattern to the NPOI data frames. The procedure is quite computationally intensive, but gives a better estimation of the phase than the conventional method of locating the peak of the group delay power. We mention briefly some of the most important past work on coherent ... |
|
| Computational Fluid Dynamics Analysis of Shock Propagation and Reflection in a Pulse Detonation Engine Combustor |
DEC 2003 |
123 pages |
| Authors:
Jimmy K. Chan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The ability to enhance detonation wave transmission at a diffraction plane through various shock reflection/focusing conditions was evaluated numerically. The geometry dimensions were generally representative of the condition existing in a valve-less pulse detonation engine developed by the Naval Postgraduate School and consisted of a small cylindrical "initiator" combustor which transmitted a shock wave to a larger diameter combustor. The wall cross section of the larger combustor was varied to ... |
|
| Validation of Respirator Filter Efficacy |
20 MAR 2003 |
78 pages |
| Authors:
James T. Hanley; Karin K. Foarde; RESEARCH TRIANGLE INST (RTI) INST RESEARCH TRIANGLE PARK NC
|
| This objective of this project was to verify by direct measurement the filtration efficiency of the gas mask C2A1 canister in light of new bioaerosol threats. HEPA filters are routinely tested using an oil aerosol at the most penetrating particle diameter at 0.3 micrometer to verify that the efficiency is at least 99.97%. The program addressed two questions: 1. What is the filtration efficiency of the C2A1 canister under use ... |
|
| Initiation of Detonation in a Large Tube |
2003 |
5 pages |
| Authors:
Viswanath Katta; Colin Tucker; John Hoke; Fredric Schauer; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| One of the important design criteria in the development of Pulse Detonation Engines (PDEs) is to stabilize detonation in a large-diameter tube in the shortest possible distance. The initial shock train emanating from the ignition source plays an important role in transitioning the deflagration wave into a detonation. To sustain such transition in a large diameter tube. innovative methods and strategies are required. An experimental-numerical investigation is conducted to understand ... |
|
| A Study of Link State Flooding Optimizations for Scalable Wireless Networks |
2003 |
7 pages |
| Authors:
Joseph P. Macker; Justin W. Dean; NAVAL RESEARCH LAB WASHINGTON DC INFORMATION TECHNOLOGY DIV
|
| Several methods have recently been proposed to improve link state protocol efficiency within wireless ad hoc networks. One class of approaches targets the reduction of link state control overhead that contributes to network wide broadcast storms, therefore enhancing protocol scalability. We have implemented and studied two such methods and demonstrate and discuss their relative performance characteristics. We present early simulation analysis over a number of scalability factors, including average nodal ... |
|
| Computing Diameter in the Streaming and Sliding-Window Models (Preprint) |
23 DEC 2002 |
15 pages |
| Authors:
Joan Feigenbaum; Sampath Kannan; Jian Zhang; YALE UNIV NEW HAVEN CT DEPT OF COMPUTER SCIENCE
|
| We investigate the diameter problem in the streaming and sliding-window models. We show that, for a stream of n points or a sliding window of size n, any exact algorithm for diameter requires Omega(n) bits of space. We present a simple epsilon-approximation algorithm for computing the diameter in the streaming model. Our main result is an epsilon-approximation algorithm that maintains the diameter in two dimensions in the sliding windows model ... |
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| Applications of Nanotubes in Electronic and Nanomechanical Devices |
DEC 2002 |
155 pages |
| Authors:
David Tomanek; MICHIGAN STATE UNIV EAST LANSING DEPT OF PHYSICS AND ASTRONOMY
|
| Using a combination of state-of-the-art computational techniques, the proposed research investigates the suitability of nanotubes for application in nanoscale devices. In view of the present and future Navy needs, the research focuses on applications utilizing the unusually high thermal and electrical conductivity, mechanical strength of nanotubes, as well as their potential for energy storage. Our research helps to better understand nanotube properties in case of chemically and structurally modified nanotubes ... |
|
| EOX for Noninvasive Physiologic Monitoring |
28 JUN 2002 |
4 pages |
| Authors:
Lloyd W. Hillman; Art Lompado; Patrick J. Reardon; ALABAMA UNIV IN HUNTSVILLE DEPT OF PHYSICS
|
| An EOX is an instrument that scans low-powered lasers into a subject's eye and spectroscopically determines oxygen saturation of blood within the retinal veins and arteries. Pilot animal studies performed by our group with an EOX indicate that retinal venous oxygen saturation is a sensitive indicator of blood loss. We have developed a 2-D scanning EOX which is readily reconfigured to operate at various wavelengths, and to use confocal techniques ... |
|
| Damage Assessment in TiB2 Ceramic Armor Targets |
NOV 2001 |
64 pages |
| Authors:
Nevin L. Rupert; William H. Green; Joseph M. Wells; Kevin J. Doherty; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The interaction between long rods and ceramics is only partially understood; however, this understanding is essential in the design of improved performance of impact-resistant materials and armor system design applications. The current work takes a preliminary look into the modem mythology surrounding the formation of radial cracking in ceramics during ballistic penetration. Tests were conducted using a 32-g tungsten alloy laboratory penetrator with a length to diameter ratio (L/D) = ... |
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| Confocal Microwave Imaging for Breast Tumor Detection: A Study of Resolution and Detection Ability |
25 OCT 2001 |
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| Authors:
E. C. Fear; M. A. Stuchly; VICTORIA UNIV (BRITISH COLUMBIA) DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| Confocal microwave imaging (CMI) is a recently introduced method of breast tumor detection that utilizes techniques adapted from ground penetrating radar for mine detection. Initial feasibility studies performed with simulated data indicate that CMI is a promising method for tumor detection and localization. In this paper, we explore the detection ability and resolution of the system. The detection ability is examined by imaging tumors of small diameter, while resolution is ... |
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| A Study of Discharge Coefficient in Bileaflet Valves |
25 OCT 2001 |
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| Authors:
M. Grigioni; C. Daniele; G. D'Avenio; U. Morbiducci; C. Del Gaudio; ISTITUTO SUPERIORE DI SANITA ROME (ITALY) LAB OF BIOMEDICAL ENGINEERING
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| The measurement of a cardiac valve's area is a common procedure, usually performed with noninvasive, Doppler-based techniques. Such measurements are not, however, without problems: a potential source of errors is the value of a valve's discharge coefficient. In-vitro pressure and flow measurements relative to the bileaflet valve of four brands were performed. A total of 12 valve samples was studied to cover the entire range of valve sizing. The data ... |
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| Baroreceptor-Sensitive Fluctuations of Heart Rate and Pupil Diameter |
25 OCT 2001 |
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| Authors:
G. Calcagnini; P. Giovannelli; F. Censi; P. Bartolini; V. Barbaro; ISTITUTO SUPERIORE DI SANITA ROME (ITALY) LAB OF BIOMEDICAL ENGINEERING
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| It is generally known that the pupil is under the control of the autonomic nervous system. Recently, those rhythms charactering the autonomic fluctuations of heart period and arterial blood pressure have been detected in spontaneous Pupil Diameter (PD) fluctuations. The physiological mechanisms underlying such variability have not been widely investigated. Aim of this study was to investigate the origin of the pupil fluctuations in humans, using a non- invasive modulation ... |
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