| Study of Composite Interface Strength and Crack Growth Monitoring Using Carbon Nanotubes |
Sep-2009 |
92 pages |
| Authors:
Mollie A Bily; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Interface strength of woven fabric composite layers was studied using Mode II fracture strength testing. Both carbon fiber and glass fiber composites were used with the vinyl ester resin. First, the single-step cured (i.e., co-cured) composite interface strength was compared to that of the two-step cured interface as used in the scarf joint technique. The test results showed that the two-step cured interface was as strong as the co-cured interface, ... |
|
| Demonstration of Ethanol and JP-8 Fuel Atomization Using Micromachined Silicon Multiplexed Electrosprays |
May-2009 |
24 pages |
| Authors:
C M Waits; Israel Boniche; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| This work discusses the fabrication and experimental testing of multiplexed electrospray (ESpray) devices micromachined in silicon substrates. Variations to the experimental test stands from previous work demonstrating Ethanol spraying are described for the successful demonstration of JP-8 spraying. Five different ESpray devices were microfabricated to gain an understanding of the operating limits for stable electrospraying. The microfabrication of ESpray devices consists of independently fabricating its two components (extractor and nozzle ... |
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| Thermal Conductivity Reduction in Fullerene-Enriched p-Type Bismuth Telluride-Based Composites (Preprint) |
Apr-2009 |
24 pages |
| Authors:
Terry M Tritt; J E Spowart; N Gothard; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| We present a systematic study of the effects of fullerene nano-inclusions upon a p-type bismuth-antimony-telluride matrix, where the ultimate goal is maximizing the figure of merit by reducing the thermal conductivity. Nanocomposites consisting of a bismuth telluride matrix with fullerene inclusions have been prepared both by mechanical mixing and ball milling, with the final consolidation in each case achieved by uniaxial hot pressing. A series of samples was produced with ... |
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| Acute Effects of an Alternative Electronic-Control-Device Waveform in Swine |
01-Mar-2009 |
10 pages |
| Authors:
James R Jauchem; Charles W Beason; Michael C Cook; GENERAL DYNAMICS ADVANCED INFORMATION SYSTEMS BROOKS CITY-BASE TX
|
| In previous studies, repeated 5-s exposures of anesthetized swine to an electronic control device (TASER International's Advanced TASER X26 device) resulted in acidosis and increases in blood electrolytes. In the current study, experiments were performed to investigate effects of longer continuous exposures to a different electronic control device waveform. After intramuscular injection of tiletamine HCl and zolazepam HCl, anesthesia was maintained with propofol infusion. Ten swine were exposed to either ... |
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| Electrical Exploding Nickel and Tungsten Wires in Air and Water |
Feb-2009 |
22 pages |
| Authors:
George B Vunni; OAK RIDGE INST FOR SCIENCE AND EDUCATION TN
|
| Nickel wire of diameter d = 230 microns and tungsten wire of diameter d = 150 microns were exploded in air and water. Plasmas were formed by rapid electrical discharge through thin wires in air and immersed in a water bath. Energy deposited into the wires at different stages of heating in air and water was estimated from the experiments. It was shown that 30% more energy was deposited in ... |
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| Breakdown Voltage of Thermoplastics with Clay Nanometer-Sized Fillers (Postprint) |
Dec-2008 |
6 pages |
| Authors:
Richard A Vaia; Stephen S Brandstetter; Lawrence F Drummy; John C Horwath; Daniel L Schweickart; UES INC DAYTON OH
|
| The addition of fillers are used commonly in industry to improve physical properties of polymers, such as stiffness, hardness, wear, heat distortion temperature or electrical conductivity, or to reduce the overall raw material cost of a part. The addition of nanometer-sized fillers, or nanofillers, has shown potential for impr oving the polymer's dielectric breakdown voltage in conjunction with augmentation of its mechanical properties. Five different sets of thermoplastics were tested ... |
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| Effects of Quality Composts and Other Organic Amendments and Their Humic and Fulvic Acid Fractions on the Germination and Early Growth of Slickspot Peppergrass (Lepidium Papilliferum) and Switchgrass in Various Experimental Conditions |
01-Sep-2008 |
24 pages |
| Authors:
Senesi Nicola; UNIVERSITA DI BARI (ITALY)
|
| Three representative and different composts were selected and used in this work: a green compost (GC), a mixed compost (MC) and a green coffee compost (GCC). The three composts were characterized by means of conventional methods for several chemical and physical properties, including pH, electrical conductivity (EC), moisture and ash contents, total organic carbon (TOC) content, total N content, C/N ratio and humic acid-like (HAL) content. Seeds of slickspot peppergrass ... |
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| Electrical Properties of Cu Nanowires |
Aug-2008 |
5 pages |
| Authors:
Qiaojian Huang; Carmen M Lilley; Matthias Bode; Ralu S Divan; ILLINOIS UNIV AT CHICAGO DEPT OF MECHANICAL AND INDUSTRIAL ENGINEERING
|
| Copper nanowires were patterned with e-beam lithography and fabricated with an e-beam evaporated Cu film. Electrical properties, including resistivity and temperature coefficient of resistance, were characterized for Cu nanowires with a width range of 90 nm to 330 nm. It was experimentally found that the surface and size have apparent influence on the electrical properties. The measured resistivity of the Cu nanowires was found to be size dependent, which was ... |
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| Contact Analysis of Nominally Flat Surfaces |
01-Jun-2008 |
69 pages |
| Authors:
Matthew R Shellock; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A proper understanding of the mechanism of contact between two or more nominally flat surfaces is crucial in the design process of many devices. This thesis, using analytical and computational methods, models the former through the use of fractal characteristics at the contact interface. A parametric analysis of the fractal surface was completed in order to properly understand fractal geometry and its effect on surface properties. The fractal surface was ... |
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| Evaluation of Residual Stress Relaxation in Surface-Treated Engine Alloys |
Jun-2008 |
24 pages |
| Authors:
Peter B Nagy; CINCINNATI UNIV OH DEPT OF AEROSPACE ENGINEERING AND APPLIED MECHANICS
|
| Recent research results indicate that eddy current conductivity measurements can be exploited for nondestructive evaluation of subsurface residual stresses in surface-treated nickel-base superalloy components. According to this approach, first the depth-dependent electric conductivity profile is calculated from the measured frequency-dependent apparent eddy current conductivity spectrum. Then, the residual stress depth profile is calculated from the conductivity profile based on the piezoresistivity coefficient of the material, which is determine separately from ... |
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| Multiscale Modeling and Computation of Liquid Crystal Polymers, Polymer Blends, and Polymer Nanocomposites: Investigation of Rheology and Material Properties |
15 APR 2008 |
11 pages |
| Authors:
Qi Wang; FLORIDA STATE UNIV TALLAHASSEE DEPT OF MATHEMATICS
|
| High-performance polymeric materials such as liquid crystal polymers and polymer nano-particle composites have many military applications. The project aimed to study the mesoscopic structure formation during flow processing and characterization of material properties in solid states. Significant progress has been made to model the materials and to understand their rheological properties in melt or solution processing. Electrical and thermal conduction properties of the nanocomposites are characterized by the low volume ... |
|
| Symposium U: Thermoelectric Power Generation. Held in Boston, Massachusetts on November 26-29, 2007 |
01-Apr-2008 |
29 pages |
| Authors:
Ryoji Funahashi; Jihui Yang; Timothy P Hogan; Terry M Tritt; MATERIALS RESEARCH SOCIETY WARRENDALE PA
|
| Symposium U brought together scientists and engineers working on high efficiency thermal to electric energy conversion technologies to discuss the most recent progress in materials, current theoretical and experimental trends, characterization, and device fabrication. The symposium was designed to emphasize the multi-disciplinary nature (materials science, physics, chemistry and engineering) of the research needed to advance the state-of-the-art technology. Over 175 abstracts were received. This was more than any of the ... |
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| Production of Magnesium-Based Thermoelectric-Sheet Materials for Efficient Energy Harvesting |
27-Jan-2008 |
22 pages |
| Authors:
Tatsuhiko Aizawa; ASIA SCIENCE EDUCATION ECONOMY DEVELOPMENT TOKYO (JAPAN)
|
| In the first-year of projects related to MURI-program, Mg-Si-Ge-Sn system is found to be a suitable TE-material target for improvement of specific figure-of-merit to be used as the candidate energy harvesting material. The solid-state synthesis is an only approach to utilize two material parameters of germanium and tin contents in order to optimize TE-material property. The germanium content x in Mg2Si1-x-yGexSny plays a role to control the Seebeck coefficient; while ... |
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| Scalable Quantum Information Processing and Applications |
19 JAN 2008 |
|
| Authors:
Richard S. Ross; Mark F. Gyure; Edward T. Croke; Geoffrey D. Simms; Chris Anderson; Robert Kosut; HRL LABS LLC MALIBU CA
|
 | The main goal of this program was to design fabricate and test a semiconductor device capable of demonstrating the fundamental physics required for the realization of a spin-coherent single photon transmitter/receiver system. These requirements included careful tailoring of the g factor for conduction band electrons in the InGaAs/InP materials system and the confinement detection and manipulation of single electrons under lithographically defined gates In this final report we will describe ... |
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| Nanocomposites for Enhanced Structural Integrity |
11 SEP 2007 |
12 pages |
| Authors:
H. T. Hahn; CALIFORNIA UNIV LOS ANGELES DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The main objective of the proposed research was to develop the science base necessary for full utilization of nanoreinforcements into polymers and fiber composites to improve mechanical, thermal and electrical properties. Two types of nanoreinforcements were studied: 0-dimensional SiC nanoparticles and 2-dimensional graphite nanoplatelets. As property improvements are possible only when the nanoreinforcements are uniformly dispersed in and well bound to the polymer matrix, the emphasis was on developing methods ... |
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| Microscale Self-Assembled Electrical Contacts |
SEP 2007 |
38 pages |
| Authors:
Christopher J. Morris; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Self-assembly, or the spontaneous organization of parts into larger structures via energy minimization, is an attractive solution to overcome packaging and integration challenges. Capillary forces from a molten alloy can be used to both bond microscale components and make electrical connections between them in a self-assembly process. This report presents a systematic study of a number of metal alloys and self-assembly media with the aim of reducing the metal contact ... |
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| Resonant Frequency Eddy Current Liftoff Measurements for Shot Peening Intensity Assessment in Materials (Preprint) |
JUL 2007 |
10 pages |
| Authors:
Ray T. Ko; Mark P. Blodgett; Shamachary Sathish; Thomas R. Boehnlein; DAYTON UNIV OH RESEARCH INST
|
| The shot peening intensity of nickel base materials has been examined with an innovative eddy current measurement. The goal is to provide a nondestructive tool to quantitatively evaluate the surface conditions after shot peening. Traditionally, the residual stress caused by the shot peening process can be examined by X-ray diffraction. Recent eddy current works have shown promising results in evaluating the small conductivity variation due to the residual stress. This ... |
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| Reversible Control of Anisotropic Electrical Conductivity using Colloidal Microfluidic Networks |
17 APR 2007 |
13 pages |
| Authors:
Ali Beskok; Michael Bevan; DIMITRIS LAGOUDAS; Zoubeida Ounaies; Pradipkumar Bahukudumbi; William Everett; TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION
|
| This research addresses the tunable assembly of reversible colloidal structures within microfluidic networks to engineer multifunctional materials that exhibit a wide range of electrical properties. Our work has focused on studying electric field-directed assembly of gold colloids and understanding how tuning colloidal configurations can be utilized to modulate electrical properties within a microfluidic electric circuit. More specifically, we have found that a single circuit element can act as a variable ... |
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| Optimally Designed Multifunctional Composites |
11 MAR 2007 |
8 pages |
| Authors:
Salvatore Torquato; PRINCETON UNIV NJ DEPT OF CHEMISTRY
|
| Optimally designed composite materials offer the best material systems to achieve the many demands that are being placed on structures and components in Air Force applications. We have adapted the topology optimization method to design three-dimensional composite microstructures with multi functional characteristics. These include optimal multifunctional materials with optimal electrical conductivity, thermal conductivity, elastic moduli, dielectric constant, and fluid permeability. In many instances, the optimal microstructures were entirely new, and ... |
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| Absorption of Narrow Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail (Preprint) |
JAN 2007 |
25 pages |
| Authors:
Yong Chang; Christoph H. Grein; S. Sivananthan; Shekhar Guha; S. Velicu; M. E. Flatte; V. Nathan; ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OF PHYSICS
|
| An analytical model describing the absorption behavior of Hg1-xCdxTe is developed. It simultaneously considers the contributions from non-parabolic conduction/light hole bands and parabolic heavy hole bands obtained from 14-band k˙p electronic structure calculations as well as the Urbach tail. This model smoothly fits experimental absorption coefficients over energies ranging from the Urbach tail region to the intrinsic absorption region up to at least 300 me V above the band gap. ... |
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| Rheoencephalogram Reflects Cerebral Blood Flow Autoregulation in Pigs |
2007 |
6 pages |
| Authors:
Michael Bodo; Frederick Pearce; Stephen Van Albert; Rocco Armonda; WALTER REED ARMY INST OF RESEARCH SILVER SPRING MD
|
| The objective of the present study was to compare systemic arterial pressure (SAP), rheoencephalogram (REG), and carotid flow (CF) measured by Doppler ultrasound. Twenty-eight anesthetized Yorkshire pigs were measured to evaluate Cerebral Blood Flow (CBF) Autoregulation (AR) during several CBF manipulations: hemorrhage, positive end-expiratory pressure (PEEP), and transitory SAP decrease and increase. Data were sampled with 200 Hz and processed off-line. 1) Hemorrhage elicited a decrease in SAP and transitory ... |
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| Progress Towards a Micromachined Thermoelectric Generator using PbTe and PbSnSeTe Thin Films |
NOV 2006 |
5 pages |
| Authors:
I. Boniche; C. D. Meyer; P. J. Taylor; N. K. Dhar; D. P. Arnold; FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This paper presents etching techniques and metal contact resistance studies for vapor-deposited PbTe and PbSnSeTe films to enable micromachining of thermoelectric (TE) generators within integrated MEMS devices (e.g. micro heat engines, microcombustors). Films of up to 10 micrometers were achieved using (100) silicon substrates. Single-crystal films were achieved using CdTe or ZnTe buffer layers, while polycrystalline films were formed on thermally-oxidized silicon. Processes using a bromine-based wet etch and methane-based ... |
|
| Experimental Studies of Electronic Transport of Chalcogenide Glass Electrical Switches |
01 OCT 2006 |
7 pages |
| Authors:
Dave Emin; Arthur Edwards; NEW MEXICO UNIV ALBUQUERQUE DEPT OF PHYSICS AND ASTRONOMY
|
| The electrical conductivity, Seebeck coefficient, and Hall coefficient of 3 micron thick films of amorphous Ge2Sb2Te5 have been measured as functions of temperature from room temperature down to as low as 200 K. The electrical conductivity manifests an Arrhenius behavior. The Seebeck coefficient is p-type with behavior indicative of multi-band transport. The Hall mobility is n-type and low (near 0.07 sq cm/V sec at room temperature). |
|
| Assessment of an Active Electromagnetic Sensor for Hunting Buried Naval Mines, Part II |
Sep-2006 |
9 pages |
| Authors:
P J Carroll; W M Wynn; J W Purpura; NAVAL SURFACE WARFARE CENTER PANAMA CITY FL
|
| The US Navy is investigating the use of broadband electromagnetic (EM) sensors as a candidate technology for its Buried Minehunting (BMH) sensor suite. New Navy tactics are being pursued, where short-range sensors are incorporated into reacquisition minehunting systems for short-range classification. The current approach includes study of use of active EM sensors that employ multi-frequency sources for target illumination which can provide valuable multi-spectral discrimination for the classification of buried ... |
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| Narrow Gap HgCdTe Absorption Behavior Near the Band Edge Including Nonparabolicity and the Urbach Tail |
10 AUG 2006 |
4 pages |
| Authors:
Yong Chang; Christoph H. Grein; Sivalingam Sivananthan; M. E. Flatte; V. Nathan; S. Guha; ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OF PHYSICS
|
| An analytical model describing the absorption behavior of HgCdTe is developed that simultaneously considers the contributions from nonparabolic conduction and light hole bands as calculated by a 14 X 14 matrix k-p method as well as the Urbach tail. This model is capable of smoothly fitting experimental absorption coefficient curves over energies ranging from the Urbach tail region to the intrinsic absorption region up to 300 meV above the band ... |
|
| Results of Copper-Silver Rail Materials Tests |
MAY 2006 |
9 pages |
| Authors:
Zachira Castro; Chadee Persad; TEXAS UNIV AT AUSTIN INST FOR ADVANCED TECHNOLOGY
|
| The goal of this phase of our investigation of better rail materials was to assess the multiple shot performances of copper-silver alloy (Cu-24% Ag) test coupons. The focus of these tests was on the assessment of changes in material properties and microstructure of test coupons. The primary metric used was the change in hardness. Material surface deformations and microstructure changes were evaluated by optical microscopy and scanning electron microscopy. Hardness ... |
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| Carbon Nanotube-Based Composites for Future Air Force and Aerospace Systems |
MAR 2006 |
17 pages |
| Authors:
Erik T. Thostenson; Tsu-Wei Chou; DELAWARE UNIV NEWARK
|
| Nanotubes have been targeted for potential applications ranging from the next generation of computers and flat-panel displays to structural and functional materials. In addition to their well-known stiffness (> 1 TPa) and strength (-30 GPa) properties, carbon nanotubes also possess exceptionally high electrical and thermal conductivities, with the axial thermal conductivity near that of crystalline diamond. The unique mechanical and physical properties of nanotubes offer tremendous opportunity for the development ... |
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| A Review of the Fabrication and Properties of Vapor-Grown Carbon Nanofiber/Polymer Composites (Preprint) |
MAR 2006 |
36 pages |
| Authors:
Gary G. Tibbetts; Max L. Lake; Karla L. Strong; Brian P. Rice; APPLIED SCIENCES INC CEDARVILLE OH
|
| Several varieties of vapor-grown carbon nanofibers with diameters under 200 nm and conically shaped grapheme planes canted with respect to the longitudinal fiber axis are available. Because of the strong interfiber bonding, compounding these fibers with polymeric resins demands some care. Therefore, fabrication of nanofiber composites has led to variable and occasionally disappointing electrical conductivity and tensile strength. In the following paper, we review the published data for vapor-grown carbon ... |
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| Processing and Characterization of Shape Memory Polymer Nanocomposites (Preprint) |
FEB 2006 |
|
| Authors:
David Fortener; CORNERSTONE RESEARCH GROUP INC DAYTON OH
|
| This report was developed under a SBIR contract. Cornerstone Research Group, Inc. (CRG) has demonstrated the feasibility of adding nanoparticulates into their shape memory polymer (SMP) resin systems. Under thermal or other stimuli, SMPs can exhibit a radical change from a rigid polymer to a flexible, elastic state, and then back to a rigid state again. Nanoparticles, including carbon nanofibers and carbon nanotubes, are expected to increase material properties such ... |
|
| Effects of Solar UV on Spacecraft Charging in Sunlight |
09 JAN 2006 |
6 pages |
| Authors:
Shu T. Lai; Maurice Tautz; Kent Tobiska; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Spacecraft surface charging is determined by the balance of currents. Photoelectron currents from spacecraft surfaces greatly exceed the ambient electron or ion currents and therefore are often of prime importance for charging in sunlight. The authors present a brief overview of several aspects of spacecraft charging in sunlight. For a conducting spacecraft at geosynchronous altitudes, charging in sunlight is usually up to a few positive volts only. If the spacecraft ... |
|
| Hall Mobility of Amorphous Ge2Sb2Te5 |
06 JAN 2006 |
4 pages |
| Authors:
S. A. Baily; David Emin; Heng Li; NEW MEXICO UNIV ALBUQUERQUE DEPT OF PHYSICS AND ASTRONOMY
|
| The electrical conductivity, Seebeck coefficient, and Hall coefficient of 3 micron thick films of amorphous Ge2Sb2Te5 have been measured as functions of temperature from room temperature down to as low as 200 K. The electrical conductivity manifests an Arrhenius behavior. The Seebeck coefficient is p-type with behavior indicative of multi-band transport. The Hall mobility is n-type and low (near 0.07 cm2/V sec at room temperature). |
|
| Hypersonic Inlet With Plasma Induced Compression (Postprint) |
JAN 2006 |
15 pages |
| Authors:
J. S. Shang; J. Menart; Roger L. Kimmel; J. Hayes; WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING
|
| A path-finding experimental investigation has been successfully accomplished to show the combined effect of an electromagnetic perturbation and viscous-inviscid interaction is a viable mechanism for improving hypersonic inlet performance. The plasma-induced compression is produced by a direct current discharge from electrodes embedded in the sidewalls of a rectangular constant cross-sectional area inlet. This repeatable compression acts as the sidewall compression of a variable area inlet but without the parasitic effect ... |
|
| Conservation of Lateral Momentum in Heterostructure Integrated Thermionic Coolers |
2006 |
16 pages |
| Authors:
Daryoosh Vashaee; Ali Shakouri; CALIFORNIA UNIV SANTA CRUZ SCHOOL OF ENGINEERING
|
| Thin film thermionic coolers use selective emission of hot electrons over a heterostructure barrier layer from emitter to collector resulting in evaporative cooling. In this paper a detailed theory of electron transport perpendicular to the multilayer superlattice structures is presented. Using Fermi-Dirac statistics, density-of-states for a finite quantum well and the quantum mechanical reflection coefficient, the current-voltage characteristics and the cooling power density are calculated. The resulting equations are valid ... |
|
| Design of Heterostructures for High Efficiency Thermionic Emission |
NOV 2005 |
7 pages |
| Authors:
Zhixi Bian; Ali Shakouri; CALIFORNIA UNIV SANTA CRUZ ELECTRICAL ENGINEERING DEPT
|
| We use two heterostructure designs to improve the energy conversion efficiency of solid-state thermionic devices. The first method is to use a non-planar heterostructure with roughness in order of electron mean free path. This has some combined benefits of increased effective interface area, and reduced total internal reflection for the electron trajectories arriving at the interface. Monte Carlo simulations of various geometries show that the electrical conductivity and thermoelectric figure ... |
|
| Transient Harman Measurement of the Cross-plane ZT of InGaAs/InGaAlAs Superlattices with Embedded ErAs Nanoparticles |
NOV 2005 |
7 pages |
| Authors:
Rajeev Singh; Zhixi Bian; Gehong Zeng; Joshua Zide; James Christofferson; Hsu-Feng Chou; Art Gossard; John Bowers; Ali Shakouri; CALIFORNIA UNIV SANTA CRUZ ELECTRICAL ENGINEERING DEPT
|
| The transient Harman technique is used to characterize the cross-plane ZT of InGaAs/InGaAlAs superlattice structures with embedded ErAs nanoparticles in the well layers. ErAs nanoparticles have proven to substantially reduce the thermal conductivity while slightly increasing the electrical conductivity of bulk InGaAs. The InGaAs/InGaAlAs superlattice structure was designed to have a barrier height of approximately 200meV. Although ErAs nanoparticles provide free carriers inside the semiconductor matrix, additional doping with Si ... |
|
| Complex Permittivity of Polyaniline-Carbon Nanotube and Nanofibre Composites in the X-band. PMMA Composites |
28 SEP 2005 |
|
| Authors:
Darren A. Makeiff; Trisha Huber; Paul Saville; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| Polymer composites incorporating polyaniline (PAni) and multiwalled carbon nanotubes (MWNTs) as conductive filler were synthesized and characterized using FT-IR spectroscopy, SEM, TEM, and dc conductivity measurements. The pure nanocomposite powders were significantly more conductive than PAni, MWNT, or CNFs alone. PAni, MWNT, CNFs, PAni-coated MWNT (PAni-MWNT), and PAni-coated CNF (PAni-CNF) nanocomposites were also incorporated as conductive filler into the insulating matrix, PMMA, to produce a rigid and conductive composite material ... |
|
| Patterned Electrospray Fiber Structures |
28 SEP 2005 |
24 pages |
| Authors:
Phillip Gibson; Heidi Schreuder-Gibson; ARMY NATICK SOLDIER CENTER MA
|
| Electrospun fibers have useful filtration properties for chemical protective clothing and filter masks. Techniques for the patterned deposition of these fibers have been developed based on varying the conductivity of the target substrate. We are investigating multilayer arrangements of patterned fibers deposited in single layers, and onto air-permeable substrates. Patterning through the depth and across the area of the deposited layers has an effect on membrane strength. These materials are ... |
|
| Using Geophysics to Assess the Condition of Small Embankment Dams |
JUL 2005 |
28 pages |
| Authors:
Troy R. Brosten; Jose L. Llopis; Julie R. Kelley; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| The U.S. Army Engineer Research and Development Center (ERDC) Geotechnical and Structures Laboratory conducted a program of technical and archival research to document current knowledge of indirect seepage detection and methods for monitoring the conditions within small embankment dams. This report documents current methods used to determine conditions within embankment dams by indirect means and provides guidance on determining which methods will most likely succeed at various sites. The report ... |
|
| Electrical Impedance Tomography of Breast Cancer |
01 JUN 2005 |
32 pages |
| Authors:
L. T. Muftuler; CALIFORNIA UNIV IRVINE
|
| In screening for breast cancer, once abnormalities or lesions are discovered by the X-ray mammogram, other imaging techniques are usually needed as an adjunct to diagnose the lesion as benign or malignant. It has been shown that cancer cells exhibit altered local electrical impedance. However, existing technology to measure the electrical impedance of the breast relies on a device that has poor spatial resolution. The authors proposed to map the ... |
|
| Novel Nano-Phase Ordered Polymer Systems for Efficient Photovoltaic Applications |
07 MAR 2005 |
24 pages |
| Authors:
Sam Sun; NORFOLK STATE UNIV VA
|
| A novel polythiophene -DBAB- type block copolymer system has been developed, where D is a new sulfide derivatized polythiophene donor block, A is a fluorine derivatized polythiophene acceptor block, and B is a non conjugated and flexible bridge chain. In donor block, a dithiathiophene ring derivatized polythiophene was used due to it is chemically more stable than the no-ring analogs. This structure also drastically limits the large steric hindrance in ... |
|
| Amphibious Antennas for Providing Near Vertical Incidence Skywave Communication |
23 FEB 2005 |
12 pages |
| Authors:
David R. Rivera; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This patent application discloses an amphibious antenna for providing Near Vertical Incidence Skywave (NVIS) communication when grounded to a conductive fluid. The amphibious antenna has a support member for supporting a helix. The helix includes a first helical arm that is not insulated and grounded, when in use, through a conductive fluid into which the antenna is placed, and a second helical arm that is insulated from the conductive fluid. ... |
|
| Solid Acid Based Fuel Cells |
28 JAN 2005 |
18 pages |
| Authors:
Sossina M. Haile; CALIFORNIA INST OF TECH PASADENA
|
| High power density fuel cells based on solid acid electrolytes have been demonstrated. In particular, a fuel cell with a 25 micron thick CsH2PO4 membrane was fabricated and yielded a power density of 425 mW/cm2 at 26O C (H2/ O2) without pressurization. In this configuration, the thin-film fuel cell is supported on a porous stainless steel gas diffusion layer and the electrocatalyst and electrolyte layers are spray-deposited. In parallel with ... |
|
| Tribology of Co-sputtered Nanocomposite Au/MoS2 Solid Lubricant Films Over a Wide Contact Stress Range |
15 JAN 2005 |
17 pages |
| Authors:
J. R. Lince; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| Slip-ring assemblies for spacecraft, and other sliding electrical contacts, require low friction and wear, as well as low electrical resistance and noise. Most current slip-ring technologies (both solid- and liquid- lubricated) are over forty years old, and their robustness is often less than satisfactory. Newer technologies have been developed, but have also shown limitations in spacecraft applications. We are investigating alternate material technologies to address these issues, concentrating on sputter-deposition ... |
|
| Evaluation of Sensors for On-Board Diesel Oil Condition Monitoring of U.S. Army Ground Equipment |
04 JAN 2005 |
6 pages |
| Authors:
Joel Schmitigal; Steve Moyer; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
|
| The U.S. Army Tank-Automotive Research, Development and Engineering Center (TARDEC) recently completed a Science and Technology Objective (STO) to develop and demonstrate a compact on-board smart sensor system for monitoring the operational condition of in-service diesel engine oils. The goal of such technologies is to reduce or eliminate the Army's dependence on traditional oil analysis methods, by providing real-time condition monitoring and to project the remaining usable life of the ... |
|
| Bayesian Theory Used in Designing the Ocean Floor Electromagnetic Sounding Experiment |
2005 |
|
| Authors:
Marius Birsan; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| In the Bayesian formulation of inversion the information content for each unknown parameter is quantified in terms of its marginal posterior probability distribution, which defines the accuracy expected in inversion. The problem of seafloor electromagnetic sounding is defined in terms of recovering the electrical conductivity profile beneath the seafloor from measurements of the electromagnetic field. Electromagnetic inversion represents a strongly non-linear problem for which a direct solution is not available. ... |
|
| Modeling and Analysis of a Robust Thermal Control System Based on Forced Convection Thermal Switches |
2005 |
12 pages |
| Authors:
Andrew D. Williams; Scott E. Palo; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| There is a critical need, not just in the Department of Defense (DOD) but the entire space industry, to reduce the development time and overall cost of satellite missions. To that end, the DOD is actively pursuing the capability to reduce the deployment time of a new system from years to weeks or even days. The goal is to provide the advantages space affords not just to the strategic planner ... |
|
| (Bio-Inspired Theme) The Engineering of Thermally and Mechanically Activated Nanosensors |
DEC 2004 |
23 pages |
| Authors:
Paul Blount; TEXAS UNIV AT DALLAS SOUTHWESTERN MEDICAL CENTER
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| Some biological sensors undergo structural changes, such as the opening of a large pore, upon matrix deformation. Other biological molecules have the ability to bind heavy metals, such as nickel, cadmium, copper, etc. We have been inspired by these findings to propose a fusion of these biological attributes into a single nanosensor. The long-range goal of this project is identify conditions in which we can utilize a biological mechano-sensor, MscL, ... |
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| Analysis of Localized High Magnetic Susceptibility Zones at Jefferson Proving Ground, Indiana |
DEC 2004 |
6 pages |
| Authors:
Ryan E. North; Eric W. Smith; Jose L. Llopis; Dwain K. Butler; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| Detection and discrimination of unexploded ordnance (UXO) and landmines with total field magnetic and electromagnetic induction (EMI) sensors can be severely inhibited by large variations in background magnetic susceptibility. Sites in Hawaii, USA, and similar settings have very high magnetic susceptibility over the entire site due to the basaltic soils. The basaltic soils exhibit magnetic viscosity, which is frequency dependence of the magnetic susceptibility. This makes detection of UXO or ... |
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| Nanoelectronic Chemical Sensors: Theory And Experiment |
17 NOV 2004 |
8 pages |
| Authors:
R. R. Smardzewski; N. L. JARVIS; A. W. Snow; H. Wohltjen; GEO-CENTERS INC ABERDEEN PROVING GROUND MD
|
| A new class of nanometer-scale, low power, solid state devices is being investigated for the detection of CW agents and other hazardous vapors. These nanoelectronic chemical vapor sensors, or chemiresistors are comprised of nanometer-sized gold particles (1.2-2.4nm) encapsulated by monomolecular layers of functionalized alkanethiols (R-SH) deposited as thin films on interdigitated microelectrodes. When chemical (agent, explosive) vapors reversibly absorb into these thin films, a large modulation of the electrical conductivity ... |
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| The Use of Geophysical Data in Studies of the Historical Solar-Terrestrial Environment |
29 SEP 2004 |
12 pages |
| Authors:
M. A. Shea; D. F. Smart; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Recent studies of the solar-terrestrial environment for the past 500 years have necessitated the use of a variety of historical databases: nitrates in ice cores, knowledge of large volcanic eruptions, sunspot numbers, mid-latitude aurora, and geomagnetic records. The nitrate data are being used to identify large solar proton fluence events. The volcanic records help to provide time markers for the ice core. The records of major geomagnetic storms and mid-latitude ... |
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Reports by Keyword(s)
ELECTRICAL CONDUCTIVITY
