| Layered Organization in the Coastal Ocean: Acoustical Data Acquisition Analyses and Synthesis |
04-Nov-2009 |
61 pages |
| Authors:
D V Holliday; RHODE ISLAND UNIV NARRAGANSETT GRADUATE SCHOOL OF OCEANOGRAPHY
|
 | The research conducted with the funding made available through this grant was from an ONR Departmental Research Initiative (DRI). The objective of the DRI was to better understand Layered Organization in the Coastal Ocean (LOCO). The explicit goal of the DRI was To understand the properties of densely concentrated, thin layers of planktonic biota that can occur in coastal ocean environments, and the interacting physical, chemical, biological and optical processes ... |
|
| Estimating Moving Targets Behind Reinforced Walls Using Radar |
Nov-2009 |
10 pages |
| Authors:
Arye Nehorai; Marija M Nikolic; Antonije R Djordjevic; WASHINGTON UNIV ST LOUIS MO DEPT OF ELECTRICAL AND SYSTEMS ENGINEERING
|
| We consider the estimation of moving targets located behind concrete walls reinforced with metallic bars, using radar measurements. The periodic structure of the rebar severely attenuates and distorts transmitted waveforms, which produces defocused images with ghost target estimates. We apply beamforming to estimate permittivity and thickness of the wall and number and position of the targets. The proposed solution is based on accurate physical models calculated using the method of ... |
|
| Analysis of Silicon Nitride (Si3N4) for Use in a Small Recuperated Turboshaft Engine |
21-Sep-2009 |
8 pages |
| Authors:
Richard L Jr; Stark; Michael J Vick; NAVAL RESEARCH LAB WASHINGTON DC OFF-BOARD COUNTERMEASURES BRANCH
|
| This analysis was performed to determine whether silicon nitride (Si3N4) could be used as a material for fabrication of the Small Recuperated Turboshaft Heavy Fuel Engine (SMART-HFE). Oxidation and volatilization of silicon nitride in the presence of water vapor has proven to be an issue under the conditions of turbine combustion. Through the use of previous research, the recession rates of Si3N4 were predicted for various operating conditions. The volatilization ... |
|
| Effect of Wall Sheaths on Ion Trajectories in a Hall Thruster Numerical Model |
Sep-2009 |
12 pages |
| Authors:
Regina M Sullivan; Joseph E Shepherd; Michelle K Scarfe; Ioannis G Mikellides; Lee K Johnson; CALIFORNIA INST OF TECH PASADENA
|
| A 2D framework for solving the sheath equations near a dielectric corner has been developed and applied in a quasi 2D fashion to solve for sheath thickness and potential profile. When appropriate, boundary conditions were taken from an HPHall model of an SPT-70 Hall thruster. Ion paths within the sheath were also calculated. Results suggest that the radial acceleration provided by the sheath has the ability to produce significant changes ... |
|
| Ultrasonic Phased Arrays for the Inspection of Thick-Section Welds |
Sep-2009 |
13 pages |
| Authors:
R J Ditchburn; M E Ibrahim; DEFENSE SCIENCE AND TECHNOLOGY ORGANIZATION VICTORIA (AUSTRALIA) MARITIME PLATFORMS DIV
|
| Ultrasonic phased arrays will eventually replace conventional ultrasonic methods in many nondestructive evaluation (NDE) applications. However, the transition to phased arrays is not without its pitfalls and challenges. In this report we present a summary of the advantages and limitations of phased-array ultrasonics in NDE, with specific reference to the inspection of thick-section welds. The main advantages offered by phased arrays over conventional systems are increased sensitivity, coverage and speed. ... |
|
| Spray Nonuniformities in Gas-Centered Swirl-Coaxial Injectors (Preprint) |
Jul-2009 |
7 pages |
| Authors:
Malissa D Lightfoot; Stephen A Danczyk; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Experimental studies of gas-centered swirl-coaxial (GCSC) injectors have revealed five basic types of nonuniformities in the spray. These nonuniformities can be classified as either affecting the centerline of the spray, with respect to the centerline of the injector, or affecting the temporal mass-distribution. The details of these behaviors are discussed as are possible driving factors and design criteria for avoidance. In general, high momentum flux operations are suggested for minimizing ... |
|
| Effects of Differing Carbon Nanotube Field-effect Transistor Architectures |
Jul-2009 |
22 pages |
| Authors:
Andrew M Dorsey; Matthew H Ervin; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Single-walled carbon nanotube field-effect transistors (SWCNTFETs) were fabricated with varying device architectures. Variations on the standard back-gated architecture included varying the gate oxide material and thickness, changing source and drain contact metallization, suspending the carbon nanotubes to minimize interaction with the gate oxide, and fabricating a topgated architecture employing a thin layer of aluminum oxide (Al2O3) as the gate oxide. Devices were characterized and compared to each other based on ... |
|
| Transport Imaging: Developing an Optical Technique to Characterize Bulk Semiconductor Materials for Next Generation Radiation Detectors |
Jun-2009 |
79 pages |
| Authors:
Sarah L Catalano; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Characterization of the mobility-lifetime product is critical to the development of new materials for semiconductor radiation detectors. An optical technique has been developed that allows for the direct determination of the minority carrier diffusion length, drift length, and mobility-lifetime product from a single image of the recombination luminescence in semiconductor materials. Excess carriers are generated using the electron beam in a scanning electron microscope. The charge is then drifted by ... |
|
| Interactive Raytracing: The nirt Command |
Apr-2009 |
58 pages |
| Authors:
Clifford Yapp; QUANTUM RESEARCH INTERNATIONAL INC BEL AIR MD
|
| The nirt command casts individual rays, according to user-specified options, and reports back a wide variety of information about the model along the specified ray. It is extremely useful for tasks such as measuring the thickness of objects and identifying gaps between objects. When used within the multi-device graphics editor environment, NIRT will produce a visible ray path, coloring the ray according to the geometry encountered along the ray. It ... |
|
| Mitigation Systems for Confined Blast Loading - Crew Protection in Armored Vehicles |
Apr-2009 |
151 pages |
| Authors:
Katherine M Gaulke; MARYLAND UNIV COLLEGE PARK
|
| Confined blast behavior and blast mitigation structures for the protection of occupants within a confined space subjected to high explosive blast, were examined through numerical analysis and laboratory testing. The mitigating structure's weight and geometry were of particular interest since performance was targeted for inclusion within the limited interior space of an armored vehicle. Numerical analysis using eta/VPG modeling software and LS DYNA dynamic analysis software examined the effects of ... |
|
| Patterning and Characterization of Carbon Nanotubes Grown in a Microwave Plasma Enhanced Chemical Vapor Deposition Chamber |
Mar-2009 |
127 pages |
| Authors:
Mauricio Kossler; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
|
| This research studies the growth of carbon nanotubes from a nickel catalyst to be used on a field emission device. A triode structure was created to be able to patterned the CNTs to improve the emission of electrons. Studies are performed on the effects of hydrogen pretreatment on nickel catalyst of different thicknesses and deposition methods on a silicon substrate and how it will affect the growth of carbon nanotubes ... |
|
| Oxide Semiconductors with Non-Volatile Resistance Switching |
Feb-2009 |
23 pages |
| Authors:
M Skowronski; J A Bain; P A Salvador; CARNEGIE-MELLON UNIV PITTSBURGH PA
|
| Metal-oxide-metal hetero-structures have been deposited by Pulsed Laser Deposition and sputtering and their I-V and switching characteristics investigated as a function of active oxide layer, top metal electrode type and structure, and oxide thickness. Non-volatile switching has been observed for structures containing (Pr,Ca)Mn03, (La,Ca)Mn03, (La,Sr)Mn03, Sr(Zr,Cr)03 and SrTi03 as the active layer and Mg, Cr, Cu, Ag, and Pt as the top metal. The electrical transport was due to space ... |
|
| Oxidation of ZrB2 and ZrB2-SiC Ceramics With Tungsten Additions (Preprint) |
Feb-2009 |
11 pages |
| Authors:
S C Zhang; W G Fahrenholtz; G E Hilmas; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The effect of tungsten additions on the oxidation behavior of zirconium diboride-based ceramics was studied. Four mole percent tungsten carbide was added to ZrB2. The oxidation behavior was studied using thermal gravimetric analysis and isothermal testing in flowing air. Upon heating to 1500 degrees C, the mass gain decreased from approx. 14 milligrams/(square centimeter) for nominally pure ZrB2 to approx. 4.5 milligrams/(square centimeter) for tungsten containing ZrB2. After heating to ... |
|
| Development of Carbon/Carbon Composites with Through-Thickness Carbon Nanotubes for Thermal and Structural Applications |
Dec-2008 |
34 pages |
| Authors:
Zhiyong (Richard) Liang; Chuck Zhang; FAMU/FSU COLL OF ENGINEERING TALLAHASSEE FL DEPT OF INDUSTRIAL ENGINEERING
|
| Carbon/carbon composites offer lightweight thermal protection capable of producing excellent thermal materials. To further improve the thermal conductivity along the thickness direction and the interlaminar shear strength, we studied and demonstrated a novel method to stitch carbon nanotube yarns along the through-thickness direction of carbon fiber two-dimensional precursor felt perform to make novel 3D reinforced carbon/carbon (C/C) composites. By stitching nanotube yarns, high strength and thermal conductive CNTs were incorporated ... |
|
| A Shock Tube for Downselecting Material Concepts for Blast Protection. Part I: Description of the Shock Tube and a Comparison of Flush Mounted and Recess Mounted Pressure Sensors |
Dec-2008 |
27 pages |
| Authors:
Ronald A Segars; Marina G Carboni; ARMY NATICK SOLDIER RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
|
| This report documents Part I of a study on the interaction between shock waves and material systems as part of a U.S. Army initiative to better protect individual Soldiers against novel blast threats. The research was conducted using a shock tube fabricated at the U.S. Army Natick Soldier Research, Development and Engineering Center (NSRDEC). The shock tube was used because it is less expensive than explosive blasts, allows many tests ... |
|
| High-Resolution Seismic Velocity and Attenuation Models of the Caucasus-Caspian Region |
30-Sep-2008 |
10 pages |
| Authors:
Eric Sandvol; Michael Pasyanos; Robert Mellors; Rengin Gok; Gleb Skobeltsyn; Ugur Teoman; Tea Godoladze; SAN DIEGO STATE UNIV CA
|
| The southwest edge of Eurasia is a tectonically and structurally complex region that includes the Caspian and Black Sea basins, the Caucasus Mountains, and the high plateaus south of the Caucasus. Using data from 25 broadband stations located in the region, new estimates of crustal and upper mantle thickness, velocity structure, and attenuation are being developed. Receiver functions have been determined for all stations. Depth to Moho is estimated using ... |
|
| Design Methodology for Bonded Repair to Partial Through-Thickness Damage |
Sep-2008 |
|
| Authors:
Chun H Wang; Dina Pilalis; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AIR VEHICLES DIV
|
 | Partial through-thickness damage to metallic and composite structures, like those caused by corrosion damage of metals or foreign object impact to composites, can be repaired by adhesively bonding an insert and an external doubler. The design methodology for these types of repairs is based on a simplified analysis in which the insert is assumed to be bonded to the flat bottom of the cutout area. This report presents an investigation ... |
|
| Frequency Response of Nanoelectromechanical Cantilevers Operating in Fluid |
Aug-2008 |
5 pages |
| Authors:
Michael J Martin; Brian H Houston; NAVAL RESEARCH LAB WASHINGTON DC
|
| Nano-electro-mechanical resonators used for sensing, data storage, and nano-fabrication applications are often operated as feed-back control systems. To determine the transfer function of silicon cantilevers with a width of 5.0 micrometer, a thickness of 800 nm, and lengths of 10, 15, 30, and 45 micrometer, the damping in air and liquid was simulated numerically using an integrated fluidstructure solver. Bode diagrams and Nyquist plots of the cantilever transfer function indicate ... |
|
| High Al-content AlGaN Alloys for Deep UV Laser Applications |
16-Jun-2008 |
10 pages |
| Authors:
Hongxing Jiang; Jingyu Lin; KANSAS STATE UNIV MANHATTAN
|
| We have carried out the growth and systematic studies of the optoelectronic and structural properties of AlN epilayers. The results revealed that the threading dislocation (TD) density, in particular the edge TD density, decreases considerably with increasing the epilayer thickness. The screw dislocation density was estimated to be about 5x106 cm-2 in the 4 ?m thick AlN epilaye and is more than one order of magnitude lower than that in ... |
|
| A Theoretical Study of Leading Edge Noise |
May-2008 |
41 pages |
| Authors:
Stewart Glegg; FLORIDA ATLANTIC UNIV BOCA RATON DEPT OF OCEAN ENGINEERING
|
| The report describes a theoretical procedure for calculating leading edge noise which addresses the differences found between current theoretical calculations and wind tunnel measurements of unsteady lift on airfoils in turbulent flow. The results have been compared with experiments carried at in a companion study at Virginia Tech by Dr. William Devenport. It was concluded that the effect of angle of attack on the radiated noise is relatively weak but ... |
|
| Plastic Optoelectronics: Injection Lasers Fabricated from Soluble Semiconducting Polymers and Bulk Heterojunction Solar Cells Fabricated from Soluble Semiconducting Polymers |
17 APR 2008 |
15 pages |
| Authors:
Alan J. Heeger; Guillermo Bazan; CALIFORNIA UNIV REGENTS SANTA BARBARA
|
| We summarize progress on bulk heterojunction (BHJ) "plastic" solar cells: BHJ solar cells are based on phase-separated blends of polymer semiconductors and fullerene derivatives. Because of self-assembly on the nanometer length scale, excitons formed after absorption of solar irradiation diffuse to a heterojunction prior to recombination and are dissociated at the polymer/fullerene interface. Ultrafast charge transfer from semicondueting polymers to fullerenes guarantees that the quantum efficiency for charge transfer (CT) ... |
|
| High-Speed Photographic Study of Wave Propagation and Impact Damage in Transparent Laminates |
01-Apr-2008 |
64 pages |
| Authors:
Elmar Straburger; M O Steinhauser; FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E V MUNICH (GERMANY F R)
|
| Conventional transparent armor consists of glass laminates with polymer interlayer and backing. It has been demonstrated that the materials, the ratio of materials, and the type and thickness of the interlayers affect the ballistic efficiency of the laminate. Borosilicate glass, Starphire ultra-clear soda-lime glass, and the transparent, polycrystalline ceramic AION are materials being considered for transparent armor applications. A comprehensive series of Edge-on Impact tests has been conducted in order ... |
|
| Construction and Instrumentation of Full-Scale Geogrid Reinforced Pavement Test Sections |
APR 2008 |
70 pages |
| Authors:
Karen S. Henry; Edel R. Cortez; Lawrence S. Danyluk; Gregory Brentrup; Nathan Lamie; Troy W. Arnold; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| A study is being conducted on full-scale pavement test sections to assess geogrid base reinforcement in flexible pavements representative of major highways. This report documents the construction and instrumentation of those test sections. The design of the test sections was based on a pavement design life of 3 106 equivalent single axle loads. There are two asphalt concrete and two base course thicknesses. One test section at each asphalt and ... |
|
| Design and Analysis of Orthotrophic Ring-Stiffened Cylindrical Shells Subjected to External Hydrostatic Pressure |
28 MAR 2008 |
91 pages |
| Authors:
John R. Renzi; NAVAL SURFACE WARFARE CENTER INDIAN HEAD DIV MD
|
| Three theories are presented for the analysis of ring-stiffened or monocoque cylindrical shells under hydrostatic pressure. The theories compute the stress state and the axisymmetric collapse, interbay buckling, and general instability pressures from external hydrostatic pressure loading. The theories were derived for the case of specially orthotropic material with theoretically uniform properties through the thickness; the theories apply equally to shells made of isotropic materials. A computer program, DAPS4 (Design ... |
|
| Long Life Durability of Electrodes of Electrical Resistance Change Method for Damage Monitoring of CFRP Composite Structures |
01-Mar-2008 |
16 pages |
| Authors:
Akira Todoroki; TOKYO INST OF TECH (JAPAN) DEPT OF MECHANICAL ENGINEERING
|
| Investigated the applicability of the electrical resistance change method through experiments of CFRP laminates [16-18]. Instead of using two or four electrodes, this research adopted multiple electrodes mounted on the surface of the target structure to identify delamination location and dimension. Orthotropic electric conductivity was also measured experimentally for three types of fiber volume fractions, and the paper revealed that electric conductivity in thickness direction of CFRP was approximately one ... |
|
| High-Speed Transmission Shadowgraphic and Dynamic Photoelasticity Study of Stress Wave and Impact Damage Propagation in Transparent Materials and Laminates Using the Edge-On Impact (EOI) Method |
MAR 2008 |
16 pages |
| Authors:
Elmar Strassburger; Parimal Patel; James W. McCauley; Christopher Kovalchick; K. T. Ramesh; Douglas W. Templeton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| In order to accelerate the development of validated design and predictive performance models, the Army Research Laboratory, the U.S. Army Tank Automotive Research Development and Engineering Center, and the Material Center of Excellence at Johns Hopkins University have entered into a collaboration with The Ernst-Mach Institute (EMI) of Efringen-Kirchen, Germany. The unique, fully instrumented Edge-on Impact facility at EMI, modified for dynamic photoelasticity, is being used to quantify stress wave ... |
|
| Ferroelectric Plasma Thruster |
29 FEB 2008 |
10 pages |
| Authors:
Scott D. Kovaleski; Mark A. Kemp; MISSOURI UNIV-COLUMBIA
|
| The Ferroelectric Plasma Thruster (FEPT) has been developed as an electrostatic micropropulsion thruster for the smallest classes of spacecraft. The FEPT consists of a thin wafer of lithium niobate ferroelectric material, with a solid electrode on one side, and an electrode with an aperture on the other. When radiofrequency high voltage is applied between the electrodes, through the thickness of the crystal, a combination of triple point and piezoelectric effects ... |
|
| Identification and Development of a Gelled Fuel through the Use of Liquid Gelling Agents |
01-Feb-2008 |
48 pages |
| Authors:
Claire Wells; James R Lee; Christopher Hooban; Wynn Vo; NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA
|
| The United States Forestry Service (USFS) currently uses solid powder gelling agents to create gelled gasoline for controlled burns. Because these gelling agents are difficult to mix with gasoline, nonhomogeneous solutions result. The inconsistency in the gelled gasoline results in larger quantities of it being used for controlled burns and also worsens the safety hazards associated with gel dispersion. Therefore, the project objective was to solve these problems by producing ... |
|
| Thermal Characterization of Thin Films for MEMS Applications |
FEB 2008 |
20 pages |
| Authors:
David J. Howe; Brian Morgan; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Thin film dielectrics play an important role in the fabrication and processes involved with microelectromechanical systems (MEMS). Two such dielectrics that are used widely are silicon dioxide (SiO2) and photoresist. As a large portion of these systems use the conduction of heat through SiO2 and photoresist layers, the thermal conductivity of these materials is crucial. In this work, the thermal conductivities of the above mentioned materials were determined using a ... |
|
| Sensitivity Analysis of Algan/GAN High Electron Mobility Transistors to Process Variation |
FEB 2008 |
130 pages |
| Authors:
Adam J. Liddle; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| A sensitivity analysis of AlGaN/GaN HEMT performance on material and process variations was performed. Aluminum mole fraction, barrier thickness, and gate length were varied + or - 5% over nominal values to determine how sensitive simulated device performance was to changes in these 3 parameters. Simulated data was generated with the Synopsys TCAD software suite using a physics-based HEMT model. To validate model performance, simulated data was correlated with experimental ... |
|
| A Reconnaissance Snow Survey across Northwest Territories and Nunavut, Canada, April 2007 |
FEB 2008 |
88 pages |
| Authors:
Matthew Sturm; Chris Derksen; Glen Liston; Arvids Silis; Daniel Solie; Jon Holmgren; Henry Huntington; ENGINEERING RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| During April 2007, a coordinated series of snow measurements were made across the Northwest Territories and Nunavut, Canada, during a 4200-km snowmobile traverse from Fairbanks, Alaska, to Baker Lake, Nunavut. While detailed, local snow measurements have been made as part of ongoing studies at tundra field sites in this region (Daring Lake and Trail Valley Creek in the Northwest Territories), systematic measurements at the regional scale have not been previously ... |
|
| Preparation of Ultra Thin Polystyrene, Polypropylene and Polyethylene Films on Si Substrate Using Spin Coating Technology |
04 JAN 2008 |
29 pages |
| Authors:
Evgeniya Lock; Scott Walton; Richard Fernsler; NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
|
| Preparation of ultra thin polystyrene, polypropylene and polyethylene films on silicon substrate using the spin coating technique is discussed in this report. The influence of various process parameters on the obtained film quality including Si wafer preparation, choice of solvent, influence of the solution concentration on the coating and sample positioning on the spin coater are shown. The polymer film surface morphology, thickness and chemical composition were analyzed by atomic ... |
|
| Finite-Element Micromechanical Strength Modeling and Parametric Investigation of Three-Dimensional Orthogonal Composites |
01-Jan-2008 |
34 pages |
| Authors:
Ryan L Karkkainen; Jerome T Tzeng; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Three-dimensional (3-D) reinforcement is often employed in thick composite parts to increase delamination resistance and through-thickness properties. Such materials are of particular interest for employment as insulators for the composite electromagnetic railgun insulator, which exhibits delamination as its primary failure mode. In the current study, a 3-D orthogonal woven S2-glass composite is investigated using finite-element micromechanics to characterize and evaluate its potential use in this target application. The representative volume ... |
|
| Structural Design of a NPS CubeSat Launcher |
01-Jan-2008 |
85 pages |
| Authors:
Felix Rossberg; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| To encourage student interest in space and education Stanford University and CalPoly developed the CubeSat. These picosatellites weigh about one kg and can be developed and built by students. NPS is designing CubeSats and a structure to deploy them in orbit as part of its emphasis on hands-on education This technical report deals with the development of a CubeSat Launcher (NPSCuL). NPSCuL will carry up to ten P-PODs built and ... |
|
| Estimation of Overtopping Flow Velocities on Earthen Levees Due to Irregular Waves |
JAN 2008 |
19 pages |
| Authors:
Steven A. Hughes; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| This Coastal and Hydraulics Engineering Technical Note (CHETN) provides empirical equations to estimate flow velocity and flow thickness resulting from irregular waves overtopping a trapezoidal-shaped earthen levee. The CHETN summarizes published European research with the goal of providing practicing engineers with design guidance in a concise and understandable form. Worked examples illustrate application of the empirical equations. |
|
| An Investigation of the Role of Nutrient Gradients in the Episodic Formation, Maintenance and Decay of Thin Plankton Layers in Coastal Waters |
Jan-2008 |
10 pages |
| Authors:
Alfred K Hanson; SUBCHEM SYSTEMS INC NARRAGANSETT RI
|
| Thin plankton layers are patches of phytoplankton and/or zooplankton that range in thickness from a few centimeters to a few meters yet can extend horizontally for kilometers and persist for days. Recent work has shown that thin layers can be sufficiently intense and persistent to affect the performance of current and planned Navy optical and acoustical sensors. In Hanson and Donaghay (1998) we showed how thin plankton layers are often ... |
|
| An Analysis of Magnesium Alloy AZ31B-H24 for Ballistic Applications |
DEC 2007 |
20 pages |
| Authors:
Tyrone L. Jones; Matthew S. Burkins; William A. Gooch; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The U.S. Army Research Laboratory is developing a ballistic specification for the use of magnesium alloy AZ31B-H24 as armor on Army platforms. Data were generated for a range of thicknesses of this magnesium alloy, 0.25 to 4 inches, with the use of five different projectiles. The magnesium performance is parametrically quantified on an equivalent areal density to meet the aluminum alloy 5083-H131, which means a mature, well defined, low-density metal. ... |
|
| Thin Layer Placement of Dredged Material on Coastal Wetlands: A Review of the Technical and Scientific Literature |
DEC 2007 |
9 pages |
| Authors:
Gary L. Ray; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
|
| Coastal wetlands in many areas are deteriorating due, in part, to sediment depletion, subsidence, and sea level rise. The purpose of this technical note is to review and synthesize the available scientific and technical literature concerning thin layer placement of dredged materials in wetlands to ameliorate these effects. |
|
| A Primer for the Linkage Between Unstructured Water Quality Model CE-QUAL-ICM and Structured Three-Dimensional Hydrodynamic Model CH3D-WES |
OCT 2007 |
59 pages |
| Authors:
Sung-Chan Kim; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| This Water Quality Research Program (WQRP) Technical Note (TN) describes the linkages between water quality model CE-QUAL-ICM (ICM) and three-dimensional hydrodynamic model CH3D-WES: CH3D. This TN also presents a primer for the linkages through a set of MATLAB programs. The created linkage files enable seamless operation from CH3D to ICM. |
|
| Research and Development of Coated Conductors Using Metal Organic Chemical Vapor Deposition |
SEP 2007 |
12 pages |
| Authors:
V. Selvamanickam; SUPERPOWER INC SCHENECTADY NY
|
| This is a new 3-year program to build on the success of the previously funded AFOST Contract FA9550-04-C-0020. In the last year of this program, we made major progress in both objectives of the program. We fabricated films of different thickness by our standard MOCVD processes and worked with our collaborators (ORNL, LANL, FSU,) to understand the microstructural reasons for the Ic performance using a variety of advanced characterization tools. ... |
|
| Evaluation of Dam Decommissioning in an Ice-Affected River: Case Study |
SEP 2007 |
45 pages |
| Authors:
Carrie M. Vuyovich; Kathleen D. White; ENGINEERING RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| Many dams across the United States are being decommissioned as a result of structural deficiencies or a desire to restore fish passage and to restore the natural stream. On northern rivers, darn removal affects the river ice processes and can result in increased ice jams and ice jams-related flooding. An analysis of the river system prior to darn removal is often necessary to ensure that increased ice jams, flooding, and ... |
|
| Modeling of Operating Temperature Performance of Triple Junction Solar Cells Using Silvaco's ATLAS |
SEP 2007 |
123 pages |
| Authors:
Michael H. Sanders; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The inefficiency of solar cells due to high operating temperatures presents a growing issue for the spacecraft industry. Currently, the problem is solved by accepting the manufactured designs and compensating for losses with larger solar arrays. Building upon prior thesis work at the Naval Postgraduate School, this thesis utilizes Silvaco's ATLAS software as a tool to simulate the performance of a typical InGaP/GaAs/Ge multi-junction solar cell at various temperatures. Additional ... |
|
| Modeling Plastic Shocks in Periodic Laminates with Gradient Plasticity Theories |
26 AUG 2007 |
53 pages |
| Authors:
G. Ravichandran; A. Molinari; CALIFORNIA INST OF TECH PASADENA
|
| Steady plastic shocks generated by planar impact on metal-polymer laminate composites, are analyzed in the framework of gradient plasticity theories. The laminate material has a periodic structure with unit cell composed of two layers of different materials. First and second order gradient plasticity theories are used to model the structure of steady plastic shocks. In both theories, the effect of the internal structure is accounted for at the microscopic level ... |
|
| Elimination of Aluminum Foil for 81-mm and 120-mm Mortar Ammunition Fiber Container |
AUG 2007 |
17 pages |
| Authors:
X. M. Yang; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ LOGISTICS RESEARCH AND ENGINEERING
|
| United Ammunition Container (UAC) in Milan, Tennessee is the current contractor that produces mortar ammunition inner packing fiber containers for the U.S. Army. UAC has not been able to secure any manufacturer that will agree to produce the needed aluminum foil. Apparently, it is not within the commercial standard manufacturing range, which is projected today due to its thickness, temper, and slit width. Not just any material can be used. ... |
|
| High Strain Rate Properties of Tantalum Processed by Equal Channel Angular Pressing |
AUG 2007 |
18 pages |
| Authors:
Philip J. Flater; Joel W. House; James M. O'Brien; William F. Hosford; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Current ingot refinement and solidification techniques used in tantalum processing often result in inconsistent mechanical properties. Subsequent processing by equal channel angular pressing (ECAP) has been shown to reduce or eliminate internal structural variations as well as part-to-part variability [2]. This paper presents the effects of ECAP processing on the properties of tantalum. The materials of interest are 2.5-inch round bar tantalum supplied by H.C. Starck and Cabot Supermetals. Three ... |
|
| Investigation of Superplastic Behavior in FSP 5083 Aluminum Alloy |
JUN 2007 |
65 pages |
| Authors:
Marc T. Bland; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Continuously-cast AA5083 in the form of as-cast billets 15 mm in thickness condition was subjected to friction stir processing (FSP) by five overlapping passes. The FSP utilized a tool having a pin approximately 5 mm in length, so that the process zone had a depth that was approximately one-third of the billet thickness. The solidification microstructure of the as-cast material included grains that were approximately 60 m in size as ... |
|
| Turbulence and Complex Flow Phenomena in Multi-Stage Axial Turbomachines |
10 MAY 2007 |
35 pages |
| Authors:
Joseph Katz; Charles Meneveau; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICAL ENGINEERING
|
| The objective of this project is to measure the flow within axial turbomachines and use the data to address turbulence modeling issues. Measurements are performed in two-stage transparent machines located in an optically index matched facility, which allows unobstructed 2-D and Stereo PIV measurements. Data provide insight on blade-wake, wake- boundary layer and wake-wake interactions. This report examines and elucidates several phenomena: i. Variations in turbulence within a wake generated ... |
|
| Remote Measurement of High Temperatures in the Presence of a Strong Magnetic Field |
07 MAY 2007 |
50 pages |
| Authors:
Scott F. Lord; NAVAL ACADEMY ANNAPOLIS MD
|
| The environment inside a railgun makes conventional temperature sensing techniques ineffective. Large time-varying magnetic fields induce noise into sensors with electrical connections. The high rate of change of temperature requires a fast thermal response and a fast sampling rate. Finally, the intense heat generated requires a sensor that is thermally stable over a large range of temperatures. To overcome such environmental challenges, this project utilized an interferometric technique where the ... |
|
| Dielectric Studies in Materials for High Energy Density Capacitors |
04 MAY 2007 |
53 pages |
| Authors:
Andrew J. Turo; NAVAL ACADEMY ANNAPOLIS MD
|
| The energy requirements of technologies today are more demanding than ever. The requirement for large energy storage and a quick release of that energy is becoming a greater and greater problem. Limited by size, cost, and the speed of chemical reactions, batteries need to be replaced as a primary source of stored energy. Capacitors have the ability to perform in many of the areas where batteries and other energy sources ... |
|
| A Multipurpose Projectile for Penetrating Urban Targets |
APR 2007 |
13 pages |
| Authors:
II Phillabaum Robert A.; Stephen J. Schraml; Richard L. Summers; Brett R. Sorensen; Rayment E. Moxley; James D. Cargile; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The U.S. Army Research Laboratory at the Aberdeen Proving Ground, MD is interested in developing a thin-walled munition capable of perforating an urban structure and delivering a payload intact to the interior of the structure. One of the most critical design aspects of this munition is the shell casing. Its shape, thickness, and material composition must be selected such that it has sufficient structural integrity to perforate a double-reinforced concrete ... |
|
Reports by Keyword(s)
THICKNESS
