| Spectroscopic Properties and Laser Performance of Resonantly-Pumped Cryo-Cooled Er3+:GdVO4 |
12 Mar 2012 |
6 pages |
| Authors:
N Ter-Gabrielyan; V Fromzel; W Ryba-Romanowski; T Lukasiewicz; M Dubinskii; ARMY RESEARCH LAB ADELPHI MD
|
 | We report a highly efficient cryo-cooled eye-safe laser operation of a resonantly-pumped (in-band) Er3+:GdVO4 single crystal. The maximum continuous wave (CW) power of 10.3 W with 84% slope efficiency was achieved at 1598.7 with pumping at 1538.6 nm by a spectrally-narrowed Er-fiber laser. Under the 1529 nm resonant pumping by a commercially available diode bar stack operating in a quasi-CW (QCW) mode, the laser delivered 37 W of output power ... |
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| Application of Autoassociative Neural Networks to Health Monitoring of the CAT 7 Diesel Engine |
Feb 2012 |
22 pages |
| Authors:
Andrew J Bayba; David N Siegel; Kwok Tom; ARMY RESEARCH LAB ADELPHI MD
|
| An autoassociative neural network (AANN) algorithm was applied to fault detection and classification for seeded fault testing on a Caterpillar C7 diesel engine. Data used for this work is a subset from the seeded fault testing performed at the U.S. Army Tank and Automotive Research, Development and Engineering Center (TARDEC) test cell facilities. This report extends previous work performed on fault detection and classification performed by the U.S. Army Research ... |
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| Fluorescence of Er3+:AlN Polycrystalline Ceramic |
01 Jan 2012 |
15 pages |
| Authors:
Larry D Merkle; Anthony C Sutorik; Tigran Sanamyan; Lindsay K Hussey; Gary Gilde; Christopher Cooper; Mark Dubinskii; ARMY RESEARCH LAB ADELPHI MD
|
| We report what we believe to be the first preparation and optical spectroscopy of Er(3+) doped into bulk AlN ceramic. The material was prepared via hot press sintering of AlN with Er(2)O(3) and [NH(4)][ErF(4)], which yielded fully dense, translucent, hexagonal AlN. The Er(3+) concentration is a small fraction of a percent, and resides in multiple sites, with one type of center dominant. A number of the energy levels of Er(3+) ... |
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| Neutron-Activated Gamma-Emission: Technology Review |
Jan 2012 |
48 pages |
| Authors:
Marc Litz; Christopher Waits; Jennifer Mullins; ARMY RESEARCH LAB ADELPHI MD
|
| This report describes the technical basis for the technology in place using neutron-activated gamma-backscatter techniques. Commercially available systems are used. The details of the capabilities and differences in these systems can best be compared when the technical details are understood. The choices between types of electronic neutron generators are described. The types of gamma-detectors are described and compared. The analysis techniques that produce the results within minutes are compared for ... |
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| Graphene-based Nanoelectronics (FY11) |
Jan 2012 |
76 pages |
| Authors:
Madan Dubey; Raju Nambaru; Marc Ulrich; Matthew Ervin; Barbara Nichols; Eugene Zakar; Osama M Nayfeh; Matthew Chin; Glen Birdwell; Terrance O'Regan; ARMY RESEARCH LAB ADELPHI MD
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| A large program in graphene-based nanoelectronics has continued at the U.S. Army Research Laboratory (ARL) under the auspices of the ARL Director's Strategic Initiative (DSI). An array of capabilities for graphene growth, characterization, device fabrication, and device modeling has been established, and expertise has been gained in all facets of this research. Significant results have been achieved, including growth of single-, bi-, and few-layer graphene; development of a graphene transfer ... |
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| Establishing an Experimental Testbed With Software-defined Radios |
Jan 2012 |
20 pages |
| Authors:
Gunjan Verma; Paul Yu; ARMY RESEARCH LAB ADELPHI MD
|
| Software-defined radios (SDRs) provide researchers with a powerful and flexible wireless communications experimentation platform. GNU Radio is the most popular open-source software toolkit for deploying SDRs, and is frequently used with the Universal Software Radio Peripheral (USRP). There is significant complexity involved in setting up GNU Radio with the USRP; therefore, in this report, we describe the key steps to take (and pitfalls to avoid) in order to successfully establish ... |
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| Information Processing and Quality Evaluations |
Jan 2012 |
9 pages |
| Authors:
Trevor Cook; Andrew Toth; ARMY RESEARCH LAB ADELPHI MD
|
| We examine the concept of Quality of Information (Qol); the idea that networked data systems can better support users if they have a notion of what the data is being used for. We argue that to judge quality it is as important to know how the data was processed as it is to know what the data says. We model Qol systems as a structure that enforces the annotation of ... |
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| Modeling of Light Airborne High-frequency (HF) Antennas |
Dec 2011 |
28 pages |
| Authors:
Christopher S Kenyon; ARMY RESEARCH LAB ADELPHI MD
|
| Performance of three lightweight, high-frequency (HF), airborne antenna designs are compared using FEKO method-of-moments modeling software. Of interest were the beam patterns near the ground. All three are upside down with -wave counterpoise wires at the top. The antennas are fed between the base and the counterpoises. Two are -wave monopole antennas while a third is a combination of cross-connected half and -wave coaxial lines. Field strengths reaching the ground ... |
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| CdTe Photovoltaic Devices for Solar Cell Applications |
Dec 2011 |
14 pages |
| Authors:
Priyalal Wijewarnasuriya; ARMY RESEARCH LAB ADELPHI MD
|
| Cadmium telluride (CdTe) has been recognized as a promising photovoltaic material for thin-film solar cells because of its near optimum bandgap of approx. 1.5 eV and high absorption coefficient. The energy gap is near optimum for a single junction solar cell and the high absorption coefficient allows films as thin as 2 microns to absorb more than 98% of the above-bandgap radiation. Cells with efficiencies near 17% have been produced ... |
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| Physics Based Analysis of Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) for Radio Frequency (RF) Power and Gain Optimization |
Dec 2011 |
14 pages |
| Authors:
Pankaj B Shah; Joe X Qiu; ARMY RESEARCH LAB ADELPHI MD
|
| The power and gain characteristics of a power radio-frequency (RF) gallium nitride (GaN) high electron mobility transistor (HEMT) were investigated by using drift-diffusion model simulations that were self consistently solved with the current-voltage (I-V) characteristics of the external circuit elements. The results showed the expected drop in gain with frequency, as the corresponding output power increases, can be modeled with device physics considerations. This technique can be used to optimize ... |
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| The Impact of GaN/Substrate Thermal Boundary Resistance on a HEMT Device |
Nov 2011 |
10 pages |
| Authors:
Horacio C Nochetto; Nicholas R Jankowski; Avram Bar-Cohen; ARMY RESEARCH LAB ADELPHI MD
|
| The present work uses finite element thermal simulations of Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) to evaluate the impact of device design parameters on the junction temperature. In particular the effects of substrate thickness, substrate thermal conductivity, GaN thickness, and GaN-to-substrate thermal boundary resistance (TBR) on device temperature rise are quantified. In all cases examined, the TBR was a dominant factor in overall device temperature rise. It is ... |
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| Characterization and Potential Application of Next Generation Commercial Surface Enhanced Raman Scattering Substrates |
Nov 2011 |
30 pages |
| Authors:
Mikella E Hankus; Ellen L Holthoff; Dimitra N Stratis-Cullum; Paul M Pellegrino; ARMY RESEARCH LAB ADELPHI MD
|
| The development of a sensing platform capable of detecting and identifying hazards, including biological, chemical, and energetic platforms, is a long sought-after goal of the Army and first responder communities. Surface-enhanced Raman scatting (SERS) is a spectroscopic technique gaining popularity as a solution to many sensing needs due to its numerous advantages such as high sensitivity, little to no sample preparation required, and use in numerous environmental settings. Despite all ... |
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| Remote Interrogation and Powering of a Spin Torque Nano-oscillator for Standoff Sensing |
Nov 2011 |
18 pages |
| Authors:
Jesse Campbell; Theodore Anthony; Chris Fazi; Alma E Wickenden; ARMY RESEARCH LAB ADELPHI MD
|
| Passively powered devices are becoming more essential when designing centimeter-scale communication capable devices. Power components are often the majority of the weight in small robots, so eliminating the onboard power source will give engineers and scientists the ability to scale down devices. An X-band wafer level antenna on a 16- by 16-mm wafer that will harvest power from a base station with the intent of providing drive current to a ... |
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| Temperature Dependence of GaN HEMT Small Signal Parameters |
Nov 2011 |
5 pages |
| Authors:
Ali M Darwish; Amr A Ibrahim; H A Hung; ARMY RESEARCH LAB ADELPHI MD
|
| This study presents the temperature dependence of small signal parameters of GaN/SiC HEMTs across the 0-150 deg C range. The changes with temperature for transconductance (gm), output impedance (C(ds) and R(ds)), feedback capacitance (C(dg)), input capacitance (C(gs)), and gate resistance (R(g)) are measured. The variations with temperature are established for g(m), C(ds), R(ds), C(dg), C(gs), and R(g) in the GaN technology. This information is useful for MMIC designs. |
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| Measurement of Upconversion in Er:YAG via Z-scan |
Oct 2011 |
5 pages |
| Authors:
Jeffrey O White; Carl E Mungan; ARMY RESEARCH LAB ADELPHI MD
|
| We demonstrate the use of the z-scan technique for measuring the upconversion coefficient in Er:YAG. The upconversion coefficient is found to be linearly proportional to the concentration for samples of concentration 0:5-3:0 at:%. A fit to four samples at room temperature yields a value of C(up) = (2.0 +/- 0.5) x 10(exp -17) cu cm/s/at:%. The coefficient at liquid-nitrogen temperatures is C(up) = (9.5 +/- 2.4) x 10(exp -17) cu ... |
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| The Resonantly Diode Pumped, Cryogenic Ho3+:YVO4 2.05-Micrometers Laser |
Oct 2011 |
12 pages |
| Authors:
George A Newburgh; Mark Dubinskii; ARMY RESEARCH LAB ADELPHI MD
|
| We report what is believed to be the first laser operation based on Ho(3+)-doped yttrium orthovanadate (YVO(4)). The cryogenic (77 K) Ho(+3):YVO(4) was resonantly diode-pumped at approximately 1.93 microns to produce up to 1.6 W of continuous wave (CW) output power at approximately 2.054 microns. The laser had a slope efficiency of approximately 38% with respect to absorbed power. We have measured the absorption and stimulated emission cross sections of ... |
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| Attenuation of Spurious Impulses from an Ultra-Wideband Radar: A High-Speed Switch for the Synchronous Impulse Reconstruction (SIRE) Frontend |
Sep 2011 |
36 pages |
| Authors:
Gregory Mazzaro; Marc Ressler; Gregory Smith; Francois Koenig; ARMY RESEARCH LAB ADELPHI MD
|
| The performance of ultra-wideband (UWB) radar systems suffers from reflections between frontend components caused by impedance mismatch. The Synchronous Impulse Reconstruction (SIRE) radar built by the U.S. Army Research Laboratory (ARL) is no exception. While most of the radio frequency (RF) energy in each impulse is transmitted by the radar as desired, a portion of the RF energy reflects within the radar frontend. Undesired impulse echoes arrive back at the ... |
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| User-based Software Tool for S-Parameter Conversion and Manipulation |
Sep 2011 |
22 pages |
| Authors:
Scott Trocchia; Tony Ivanov; Robert Proie; ARMY RESEARCH LAB ADELPHI MD
|
| S-parameters fully characterize the linear behavior of an arbitrary number of ports. We aim to characterize various field-effect transistors (FETs), each having a certain gate width and geometry, from their S-parameters. We extract the data from the vector network analyzer in real-time and perform a series of calculations and conversions on the initial S-parameters. Using a software tool written in C++ that interfaces with the vector network analyzer (VNA), the ... |
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| Experiments in Cold Atom Optics at ARL I: Introduction to Atom Chip Set-up |
Sep 2011 |
28 pages |
| Authors:
Jason Alexander; Christopher Rowlett; Violeta Prieto; William Golding; Patricia Lee; ARMY RESEARCH LAB ADELPHI MD
|
| Gyroscopes based on ultracold atom interferometry have the potential to exhibit an intrinsic sensitivity larger by a factor of 4 x 1010 than for light-based interferometers. One of the major technical challenges for the advancement of atom optics and development of practical guided matter wave interferometers is the realization of coherent beam splitters. The overall focus of our research program is to develop a physical understanding of the conditions needed ... |
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| Using a Volume Bragg Grating Instead of a Faraday Isolator in Lasers Incorporating Stimulated Brillouin Scattering Wavefront Reversal or Beam Cleanup |
29 Aug 2011 |
|
| Authors:
John E McElhenny; Jeffrey O White; Steven D Rogers; Tigran Sanamyan; Leonid B Glebov; Oleksiy Mokhun; Vadim I Smirnov; ARMY RESEARCH LAB ADELPHI MD
|
 | A master-oscillator power-amplifier with stimulated Brillouin scattering (SBS) beam cleanup or wavefront reversal typically incorporates a Faraday isolator to outcouple the Stokes light, limiting the power scalability. Volume Bragg gratings (VBGs) have the potential for scaling to higher powers. We report here the results of tests on a VBG designed to resolve wavelengths 0.060 nm apart, corresponding to the 16 GHz frequency shift for SBS backscattering at 1064 nm in ... |
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| Select Papers. Volume 1 |
Aug 2011 |
246 pages |
| Authors:
ARMY RESEARCH LAB ADELPHI MD
|
| The ARL Summer Student Research Symposium is an ARL Director s Award Program for all the students participating in various summer scholarship and contract activities across ARL. The goal of the program is to recognize and publicize exceptional achievements made by the students and their mentors in the support of Army science. All college undergraduate and graduate students receiving research appointments and conducting summer studies at ARL are automatically enrolled ... |
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| Compendium of Abstracts. Volume 2 |
Aug 2011 |
130 pages |
| Authors:
ARMY RESEARCH LAB ADELPHI MD
|
| The ARL Summer Student Research Symposium is an ARL Director s Award Program for all the students participating in various summer scholarship and contract activities across ARL. The goal of the program is to recognize and publicize exceptional achievements made by the students and their mentors in the support of Army science. All college undergraduate and graduate students receiving research appointments and conducting summer studies at ARL are automatically enrolled ... |
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| Integrated Thin-film Piezoelectric Traveling Wave Ultrasonic Motor |
Aug 2011 |
18 pages |
| Authors:
Ryan Rudy; ARMY RESEARCH LAB ADELPHI MD
|
| An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors (USMs) at the millimeter-scale is being developed for low power, high torque motors for small-scale robotics, biomedical, and sensing applications. This paper describes the realization of ultrasonic motor stators ranging in diameter from 1?3 mm using wafer-scale micro-electromechanical system (MEMS) fabrication techniques with lead zirconate titanate (PZT) thin films. Using laser Doppler vibrometry (LDV), controlled traveling waves ... |
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| Review of Current Aided/Automatic Target Acquisition Technology for Military Target Acquisition Tasks |
Jul 2011 |
10 pages |
| Authors:
James A Ratches; ARMY RESEARCH LAB ADELPHI MD
|
| Aided and automatic target recognition (Ai/ATR) capability is a critical technology needed by the military services for modern combat. However, the current level of performance that is available is largely deficient compared to the requirements. This is largely due to the difficulty of acquiring targets in realistic environments but has also been due to the difficulty in getting new concepts from, for example, the academic community, due to limitations for ... |
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| High Efficiency c-Silicon Solar Cells Based on Micro-Nanoscale Structure |
JUN 2011 |
24 pages |
| Authors:
Fred Semendy; Priyalal Wijewarnasuriya; Nibir K. Dhar; ARMY RESEARCH LAB ADELPHI MD
|
| This report describes our aim to develop high-efficiency crystalline silicon (c-Si) solar cells with increased power conversion efficiency (>30%) in order to reduce solar array mass, stowed volume, and cost. Our approach is based upon increasing the electrical junction area per unit volume using microblock design and fabrication. Current thin-film and c-Si solar cells have a limited conversion efficiency of 10-20% and cost $3-$5/W-peak and state-of-the-art crystalline multijunction solar cells ... |
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| Integration of Communication and Social Network Modeling Platforms using ELICIT and the Wireless Emulation Laboratory |
JUN 2011 |
43 pages |
| Authors:
Kevin Chan; Ryan Pressley; Brian Rivera; Mary Ruddy; ARMY RESEARCH LAB ADELPHI MD
|
| Creating models and experiment platforms that study the relationships and interactions between composite networks will enable the design of tactical networks to maximize mission performance of an organization. Tactical environments can be conceptualized by complex networks, a composition of communication, social/cognitive, and information networks. We describe an approach to integrate ELICIT (Experimental Laboratory for Investigating Collaboration, Information-sharing and Trust) with an existing wireless emulation test bed, the Wireless Emulation Laboratory ... |
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| Fly-Ear Inspired Micro-Sensor for Sound Source Localization in Two Dimensions |
May 2011 |
7 pages |
| Authors:
A P Lisiewski; H J Liu; M Yu; L Currano; D Gee; ARMY RESEARCH LAB ADELPHI MD
|
| Inspired by the hearing organ of the fly Ormia ochracea, a miniature sound localization sensor is developed, which can be used to pinpoint a sound source in two dimensions described by the azimuth and elevation angles. The sensor device employs an equilateral triangle configuration consisting of three mechanically coupled circular membranes whose oscillations are detected by a fiber-optic system. The experimental results indicate that significant amplification of the directional cues ... |
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| Hostile Fire Defeat ATO: A Quick Look at C&C and Resource Cueing |
May 2011 |
14 pages |
| Authors:
Jesse B Kovach; Christopher H Winslow; ARMY RESEARCH LAB ADELPHI MD
|
| A summary of the experimental Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) system used at the 2010 Capstone Experiment for the Hostile Fire Defeat Army Technology Objective (HFD ATO) is presented. The overview includes discussion of the Common Operating Picture (COP), the use of Cursor on Target (CoT) as an interoperability vehicle, and the presentation of a new and novel resource cueing system that makes use of SQLite ... |
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| The Virtual Collaboration Environment: New Media for Crisis Response |
MAY 2011 |
11 pages |
| Authors:
Gerhard Wickler; Austin Tate; Stephen Potter; Jeffrey Hansberger; ARMY RESEARCH LAB ADELPHI MD
|
| This paper concerns the use of new media technologies, including virtual worlds and web 2.0, for on-line collaborative activities, and specifically for the provision of expert advice about the response to large-scale crises. Internet technologies in general offer rich possibilities for interactions involving remote experts; however, the diversity, novelty and power of these technologies are such that to introduce them into problem-solving episodes without first developing a model of the ... |
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| An HLA-Based Approach to Quantify Achievable Performance for Tactical Edge Applications |
MAY 2011 |
14 pages |
| Authors:
Brian Rivera; John A. Tufarolo; Gary Comparetto; Vinay Lakshminarayan; Mohammad Mirhakkak; Ernest H. Page; Nancy Schult; David Yoo; ARMY RESEARCH LAB ADELPHI MD
|
| The DoD is pursuing an end-to-end, seamless, network-centric enterprise communications infrastructure to support a wide range of operating conditions and network topologies. Evaluating the achievable performance of this communications infrastructure, as it evolves, is essential to the user community in order to guide their ongoing requirements, design, and procurement activities. Tactical edge applications present significant challenges to network evaluation methods since they often include mobile ad-hoc networks (MANETs) that employ ... |
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| Service-oriented Reasoning Architecture for Resource-Task Assignment in Sensor Networks |
APR 2011 |
13 pages |
| Authors:
Geeth de Mel; Flavio Bergamaschi; TIEN PHAM; Wamberto Vasconcelos; Tim Norman; ARMY RESEARCH LAB ADELPHI MD
|
| The net-centric ISR/ISTAR networks are expected to play a crucial role in the success of critical tasks such as base perimeter protection, border patrol and so on. To accomplish these tasks in an effective and expedient manner, it is important that these networks have the embedded capabilities to discover, delegate, and gather relevant information in a timely and robust manner. In this paper, we present a system architecture and an ... |
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| Ultra Wideband (UWB) Synchronous Impulse Reconstruction (SIRE) Radar Upgrade Assessment Field Experiment |
Apr 2011 |
32 pages |
| Authors:
Brian Stanton; Francois Koenig; Greg Mazzaro; Marc Ressler; Kelly Sherbondy; Gregory Smith; ARMY RESEARCH LAB ADELPHI MD
|
| Several upgrades have been incorporated into the Ultra Wideband (UWB) Synchronous Impulse Reconstruction (SIRE) radar, which includes: (a) Augmented Reality, (b) antenna array mounting structure, (c) electronic switch and electro-mechanical relay, and (d) low noise amplifiers. The purpose of the experiment is to assess UWB SIRE radar upgrades. |
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| A Numerical Technique for Removing Residual Gate-Source Capacitances When Extracting Parasitic Inductance for GaN High Electron Mobility Transistors (HEMTs) |
Mar 2011 |
16 pages |
| Authors:
Benjamin Huebschman; Pankaj B Shah; ARMY RESEARCH LAB ADELPHI MD
|
| The design of monolithic microwave integrated circuits (MMIC) is dependent on the ability to generate accurate device models. Prior knowledge of the external parasitic components is required to determine the small signal model of the intrinsic device. A simple technique for determining and correcting for the gate-source capacitance during the extraction of the series inductance will be presented. This technique has worked well when integrated into existing small signal extraction ... |
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| Results of Bare Die Testing of Optimized (2nd Pass) Gallium Arsenide (GaAs) Integrated Circuit Radio Frequency (RF) Booster Designs for 425 MHz and Dual Band (425 and 900 MHz) |
Feb 2011 |
62 pages |
| Authors:
John E Penn; ARMY RESEARCH LAB ADELPHI MD
|
| High-performance microwave and radio frequency integrated circuits (RFICs) are of interest to the Army. Several monolithic microwave integrated circuits (MMICs) were designed to enhance the performance of commercial-off-the-shelf (COTS) RFICs used in many wireless systems. This report documents the bare die probe testing of ten MMIC designs optimized for 400?950 MHz operation. These designs include active RF front end designs, as well as integrated passive matching circuits to reduce SWAP ... |
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| SWCNT Supercapacitor Electrode Fabrication Methods |
Feb 2011 |
20 pages |
| Authors:
Matthew H Ervin; Benjamin S Miller; Brendan Hanrahan; ARMY RESEARCH LAB ADELPHI MD
|
| This work systematically compares various solution-based electrode fabrication methods (drop casting, air brushing, filtration, and electrospraying) to determine if there is an optimum method for fabricating supercapacitor electrodes out of single-wall carbon nanotubes (SWCNT). We have found that it is best to use SWCNT solutions free from additives that may be difficult to remove from the fabricated electrode. In addition, the SWCNT solution processing (e.g., dilution and sonication) has a ... |
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| Network Science for Decision-making: Impact of Distributed Information Quality on Performance of Decision-Making Groups |
Feb 2011 |
24 pages |
| Authors:
Kevin Chan; Brian Rivera; ARMY RESEARCH LAB ADELPHI MD
|
| Within tactical networks, communication networks support command and control organizations and social networks by enabling the flow of information. The connectivity and quality of service of the communication network results in a varying degree of mission performance. We consider this problem from a network science perspective, assuming that these networks are comprised of communication, social/cognitive, and information networks; and are characterized by the interactions between these constituent networks. We previously ... |
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| Beyond Graphs: Capturing Groups in Networks |
Jan 2011 |
7 pages |
| Authors:
R Ramanathan; A Bar-Noy; P Basu; M Johnson; W Ren; A Swami; Q Zhao; ARMY RESEARCH LAB ADELPHI MD
|
| Currently, the de facto representational choice for networks is graphs. A graph captures pairwise relationships (edges) between entities (vertices) in a network. Network science however, is replete with group relationships that are more than the sum of the pairwise relationships. For example, collaborative teams, wireless broadcast, insurgent cells, coalitions all contain unique group dynamics that need to be captured in their respective networks. We propose the use of the (abstract) ... |
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| RoboLeader: Dynamic Re-Tasking for Persistence Surveillance in an Urban Environment Using Robot-to-Robot Control |
JAN 2011 |
26 pages |
| Authors:
Jessie Y. Chen; Michael J. Barnes; Zhihua Qu; ARMY RESEARCH LAB ADELPHI MD
|
| In the FY09 DRI, we developed the RoboLeader intelligent agent that had the capabilities of coordinating a team of ground robots and revising route plans for the robots based on battlefield intelligence. In the current DRI, the capabilities of RoboLeader were expanded to deal more specifically with dynamic re-tasking requirements based on battlefield developments as well as coordination between aerial and ground robots in pursuit of moving targets. The results ... |
|
| Graphene Growth via Carburization of Stainless Steel and Application in Energy Storage |
Jan 2011 |
5 pages |
| Authors:
Hemtej Gullapalli; Arava L Reddy; Stephen Kilpatrick; Madan Dubey; Pulickel M Ajayan; ARMY RESEARCH LAB ADELPHI MD
|
| A modified version of the carburization process, a widely established technique used in the steel industry for case hardening of components, is used for the growth of graphene on stainless steel. Controlled growth of high-quality single- and few-layered graphene on stainless steel (SS) foils through a liquid-phase chemical vapor deposition (CVD) technique is reported. Reversible Li intercalation in these graphene-on-SS structures is demonstrated, where graphene and SS act as electrode ... |
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| Streak Spectrograph Temperature Analysis from Electrically Exploded Ni/Al Nanolaminates |
Jan 2011 |
7 pages |
| Authors:
Christoper J Morris; Paul Wilkins; Chadd May; Eugene Zakar; Timothy P Weihs; ARMY RESEARCH LAB ADELPHI MD
|
| We report on electrically-induced heating and mixing of multilayered nickel/aluminum (Ni/Al) laminates observed by streak camera emission spectroscopy. Past experiments probing the kinetic energy of material ejected from the reaction zone indicate that additional kinetic energy originates from Ni/Al samples, presumably from exothermic mixing between the two metals. Here we examine streak spectrographs of similar experiments to determine the presence of expected elements and their temperatures. We conducted these experiments ... |
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| Heat-Treated Metal Phthalocyanine Complex as an Oxygen Reduction Catalyst for Non-Aqueous Electrolyte Li/air Batteries |
2011 |
6 pages |
| Authors:
Sheng S. Zhang; Xiaoming Ren; Jeffrey Read; ARMY RESEARCH LAB ADELPHI MD
|
| In this work we study heat-treated FeCu-phthalocyanine (FeCuPc) complexes as the catalyst for oxygen reduction in non-aqueous electrolyte Li/air cells by supporting the catalyst on a high surface area Ketjenblack EC-600JD carbon black. It is shown that the resultant FeCu/C catalyst not only accelerates the two-electron reduction of oxygen as "O2 + 2Li+ +2e Li2O2" but also catalyzes the chemical disproportionation of Li2O2 as "2Li2O2 2Li2O+O2" In Li/air cells, the ... |
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| Network Device Checklist Automator |
Nov 2010 |
32 pages |
| Authors:
Donald A Bennett; Aaron P Hiltgen; ARMY RESEARCH LAB ADELPHI MD
|
| The Department of Defense (DoD) 8500 series mandates that all agencies implement the Security Technical Implementation Guides (STIGs) released by the Defense Information Systems Agency (DISA) to protect information systems against attackers and misuse. Agencies are required to perform regular checks on all their systems for compliance with these regulations. To make the STIG compliance validation process easier, the DoD allows the use of Security Readiness Review Scripts (SRRS), which ... |
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| Dynamics of Photo-Excited Carriers and Coherent Effects in GaN Under Subpicosecond Laser Pulse Excitation |
Nov 2010 |
38 pages |
| Authors:
Sergey Rudin; Enrico Bellotti; Gregory A Garrett; Michael Wraback; ARMY RESEARCH LAB ADELPHI MD
|
| We applied the Semiconductor Bloch Equations formalism to study the subpicosecond dynamics of photo-excited carriers in gallium nitride (GaN). The kinetics equations were derived using a two-band model and taking into account the coherent interaction of semiconductor with the short laser pulse. Various scattering terms due to interaction of carriers with polar optical phonons and carrier-carrier interaction were taken into account. Effects of the conduction band nonparabolicity and static screening ... |
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| Extraction of the Velocity of Walking Human's Body Segments using Ultrasonic Doppler |
NOV 2010 |
8 pages |
| Authors:
Asif Mehmood; James M. Sabatier; Marshall Bradley; Alexander Ekimov; ARMY RESEARCH LAB ADELPHI MD
|
| The focus of this paper is to experimentally extract the Doppler signatures of a walking human's individual body segments using an ultrasonic Doppler system (UDS) operating at 40 kHz. In a human's walk, the major contribution to Doppler velocities and acoustic scattering is from the foot, lower leg, thigh (upper leg) and torso. The Doppler signature of these human body segments are extracted experimentally. The measurements were made by illuminating ... |
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| Applications of Fresnel-Kirchhoff Diffraction Theory in the Analysis of Human-Motion Doppler Sonar Grams |
NOV 2010 |
7 pages |
| Authors:
Marshall Bradley; James J. Sabatier; ARMY RESEARCH LAB ADELPHI MD
|
| Observed human-gait features in Doppler sonar grams are explained by using the Boulic-Thalmann (BT) model to predict joint angle time histories and the temporal displacements of the body center of mass. Body segments are represented as ellipsoids. Temporally dependent velocities at the proximal and distal end of key body segments are determined from BT. Doppler sonar grams are computed by mapping velocity-time dependent spectral acoustic-cross sections for the body segments ... |
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| Consensus Algorithms Over Fading Channels |
Oct 2010 |
7 pages |
| Authors:
Kevin Chan; Ananthram Swami; Qing Zhao; Anna Scaglione; ARMY RESEARCH LAB ADELPHI MD
|
| Consensus algorithms permit the computation of global statistics via local communications and without centralized control. We extend previous results by taking into account fading and unidirectional links in ring and random 2-D topologies. We study conditions for convergence and present simulation results to verify the analytical results in this paper. We compare the performance of consensus algorithms with a tree-based (centralized) approach. Additionally, we implement a slotted ALOHA protocol and ... |
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| Magnetic Modeling of a Rotating Flux Concentrator System Designed to Mitigate Noise in Large Magnetic Sensors |
Sep 2010 |
22 pages |
| Authors:
Gregory A Fischer; Alan S Edelstein; ARMY RESEARCH LAB ADELPHI MD
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| This report discusses the magnetic modeling results of a proof of concept system for 1/f noise mitigation in large sensors. The 1/f noise reduction is achieved by rotating flux concentrators that shift the operating frequency of the sensor to higher frequencies where 1/f noise is lower. The goal is to design systems with magnetic flux concentrators that maximize the enhancement of the field and the percentage modulation of the field ... |
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| Rapid Peptide Reagent Isolation in a Disposable Microfluidic Cartridge |
Sep 2010 |
32 pages |
| Authors:
Dimitra N Stratis-Cullum; Joshua M Kogot; Paul M Pellegrino; ARMY RESEARCH LAB ADELPHI MD
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| In this collaborative development project, the challenges in affinity reagent isolation were addressed by combining two seemingly disjoint technologies-biosynthetic display libraries and microfluidic systems. To isolate optimal ligands from these libraries, our project developed an automated magnetic bacterial cell sorting system, termed micromagnetic cell sorter (MMS), to screen microbial libraries with unprecedented throughput using a disposable microfluidic cartridge. We report on the sorting system performance in rare cell and ultra-rare ... |
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| High-impedance Buffer Amplifier For Micro-electromechanical System (MEMS) Resonator Measurements |
Sep 2010 |
16 pages |
| Authors:
Brianna Murphy; Roger Kaul; ARMY RESEARCH LAB ADELPHI MD
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| The electrical performance of micro-electromechanical system (MEMS) resonators built at the U.S. Army Research Laboratory (ARL) requires measurement techniques that do not overstress the devices. As a result, we need a high-impedance amplifier that operates over an extended frequency range suitable for use ahead of a 50-ohm vector network analyzer (VNA). The prototype amplifier buffers the resonator from the VNA. This amplifier was designed, fabricated, and tested during a fourweek ... |
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| A Review of Biological Communication Mechanisms Applicable to Small Autonomous Systems |
Sep 2010 |
108 pages |
| Authors:
Kesshi Jordan; Daniel Calderone; Alexandra Rubin; Alma E Wickenden; ARMY RESEARCH LAB ADELPHI MD
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| The field of biomimetics has grown in recent years as interest in using biology as an inspiration for technology has grown. Biology constantly optimizes mechanisms, materials, and integrated systems through natural selection. These systems and materials can be incorporated into a variety of applications, using the technology that nature has already developed as a launch point for novel solutions to engineering problems. Nature's mechanisms accomplish a variety of sensory, communications, ... |
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