Tech Briefs

Angular Random Walk Estimation of a Time-Domain Switching Micromachined Gyroscope

The primary metrics that prohibit the use of microelectromechanical systems (MEMS) gyroscopes for navigation-grade inertial navigation units (IMUs) are angle random walk (ARW), bias instability, and scale factor instability. The need for MEMS gyroscopes is due to their decreased cost, size, weight, and power (CSWaP) constraints compared to current navigation-grade solutions. Note that to avoid confusion, while in a statistical context a random walk describes a particular type of random process, ARW is used herein to quantify the effects of white, or Gaussian, noise processes on the rate estimate of a gyroscope.

Posted in: Briefs, Aerospace, Sensors, Mathematical analysis, Microelectricmechanical device, Navigation and guidance systems, Noise, Reliability

Development of High Quality 4H-SiC Thick Epitaxy for Reliable High Power Electronics Using Halogenated Precursors

Development of robust semiconductor devices with high energy efficiency and reliability is a key objective towards 'Energy Conversion and Power Management ' for naval system applications. The goal of this research is to create the fundamental knowledge needed for the development of novel approaches to synthesize high-quality, thick SiC epitaxial layers (> 100μm) for reliable high voltage (≥10kV) / high power (>100 kW) electronics for navy ship applications.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Semiconductor devices, Research and development, Materials properties, Marine vehicles and equipment

Silicon Based Mid-Infrared SiGeSn Heterostructure Emitters and Detectors

Enhancing the performance of GeSn p-i-n photodiodes using gold metal nanostructures.

The goal of this research project was to advance the science and technology of silicon-based photonic devices using SiGeSn heterostructures. Such devices work in mid-IR spectral range and form the foundation for mid-IR photonics that enable on-chip systems for applications ranging from vibrational spectroscopy, chem/bio sensing, medical/health uses, to environmental monitoring. This project was mostly directed toward improving GeSn detectors with the use of surface plasmons induced by carefully designed metal nanostructures. The goal was to replace the current mid-IR detectors that are usually photodiodes made from narrow bandgap III-V or II-VI semiconductor compounds such as InGaAs, InSb, HgCdTe (MCT) or type-II In-GaAs/InGaSb superlattice. These photodiodes are incompatible with the CMOS process and cannot be easily integrated with Si electronics. The GeSn mid-IR detectors developed in this project are fully compatible with the CMOS process.

Posted in: Briefs, Electronics & Computers, Semiconductors & ICs, Integrated circuits, Sensors and actuators, Silicon alloys

Reconfigurable Electronics and Non-Volatile Memory Research

The purpose of this research was to investigate non-volatile memory device technologies that could be applied to reconfigurable electronics applications to provide power reduction, radiation tolerance, smaller size, and improved reliability over existing non-volatile memory devices. The research encompasses: 1) materials and device design, and 2) fabrication and testing of the devices. The types of memory devices that were investigated are divided into three categories:

Posted in: Briefs, Electronics & Computers, Semiconductors & ICs, Electronic equipment, Research and development, Reliability

Energy-Filtered Tunnel Transistor: A New Device Concept Toward Extremely Low Energy Consumption Electronics

Altering the thermal characteristics of semiconductors can prolong battery life.

Excessive heat dissipation (or power consumption) of modem integrated circuits is an undesirable effect that imposes substantial limitations on the performance of many electronic devices. For example, the level of heat dissipation /power consumption of smart phones, tablets, and laptops is such that it prohibits a continuous and prolonged operation of these devices, requiring frequent recharging. Large power consumption of electronic devices requires large energy storage in batteries, increasing the battery weights that soldiers carry in their missions or the weights of remote controlled equipment such as unmanned aerial vehicles (UAVs). Therefore, technology that enables electronic devices to operate with extremely small energy consumption promises a broad range of commercial, military and space applications.

Posted in: Briefs, Electronics & Computers, Transistors, Energy conservation

Epitaxial Growth of Rhenium with Sputtering

Epitaxial superconducting films of refractory metals are a promising new template for single crystal tunnel barriers in Josephson junction quantum bit (qubit) devices. In existing Josephson junction qubits, it is believed that the widely-used amorphous AlOx tunnel barriers have undesirable two-state fluctuators. It is speculated that single-crystal tunnel barriers such as sapphire (α-Al2O3) may be free of such decoherence sources.

Posted in: Briefs, Aerospace, Defense, Materials, Computer software / hardware, Conductivity, Metals, Refractory materials

Processing and Characterization of Polycrystalline YAG (Yttrium Aluminum Garnet) Core-Clad Fibers

YAG-based fiber lasers could offer efficient operation at power levels beyond those achievable in current state-of-the-art silica-based fiber lasers if losses can be minimized. To address this, researchers have investigated creating both single-crystal and polycrystalline YAG fibers. Among the cases reported is the preparation of single-crystal YAG fibers using laser heated pedestal growth (LHPG), which resulted in fiber diameters of 400 μm and optical losses around 1–2 dB/m in the 1–3 μm wavelength range. Single-crystal YAG fibers with diameters of ~ 30 μm have even been reported.

Posted in: Briefs, Aerospace, Defense, Materials, Finite element analysis, Fiber optics, Lasers, Materials identification

Multi-Scale Analysis of Deformation and Failure in Polycrystalline Titanium Alloys Under High Strain Rates

Extensive use of titanium alloys in critical industrial and military applications, such as compressor blades of jet engines and armor of ground combat vehicles, has motivated researchers to understand, measure and tailor the mechanical properties of these alloys over a wide range of strain rates and temperatures. Of special interest has been the mechanical response of these alloys under high rates of deformation and failure under cyclic/dwell fatigue.

Posted in: Briefs, Aerospace, Defense, Materials, Aircraft structures, Body panels, Failure modes and effects analysis, Materials properties, Titanium alloys, Military vehicles and equipment

Abrasion Testing of Products Containing Nanomaterials

This SOP describes how to detect and quantify the release of nanoparticles from surface coatings into the air using a mechanical process that employs abrasion to simulate sanding. A material containing nanoparticles will be physically abraded and the materials released will be collected in a custom abrasion testing system. They will then be characterized by different methods such as Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) and other methods.

Posted in: Briefs, Aerospace, Defense, Materials, Microscopy, Nanomaterials, Wear, Test procedures

Spectrum Fatigue of 7075-T651 Aluminum Alloy Under Overloading and Underloading

Most structural members and machine components are subjected in service to cyclic loadings of varying amplitude. The variation in stress level follows either a regular or random pattern. The resulting crack growth is affected by the applied load sequence in the early stage (crack initiation) and in the later stage (crack propagation) of fatigue. The fatigue crack growth is known to be retarded by tensile overloads and accelerated by compressive overloads (underloads). However, the phenomenon and mechanism of the load sequence effects, especially those of overloading and underloading, on fatigue crack growth in different environments remain to be clarified.

Posted in: Briefs, Aerospace, Defense, Materials, Failure modes and effects analysis, Aluminum alloys, Fatigue

Secret Sharing Schemes and Advanced Encryption Standard

There are many secret sharing schemes and variations available to hide and reconstruct the given secret. Shamir’s Secret Sharing Scheme, making use of linear Lagrange interpolation on the dealer-generated polynomial, was used to reconstruct the secret from the stipulated threshold number of participants’ shares. Such a scheme had been widely analyzed by mathematicians and computer scientists for potential weaknesses in the reconstruction of the secret by an external eavesdropper.

Posted in: Briefs, Defense, Software, Architecture, Computer privacy, Cryptography, Cyber security

SIPHER: Scalable Implementation of Primitives for Homomorphic Encryption

Prior to the Proceed program, the main challenges preventing practical demonstrations and use of Fully Homomorphic Encryption (FHE) were efficiency and scalability. At the start of the Program, the state-of-the-art FHE implementations were both inefficient and not scalable. Work in Scalable Implementation of Primitives for Homomorphic EncRyption (SIPHER) has brought FHE into the realm of practice, bringing several orders of magnitude runtime improvement, and resulting in FHE implementations that can be executed on single and multicore computers (including iPhones). Furthermore, implementation of an FHE hardware accelerator on a Virtex 7 Field Programmable Gate Array (FPGA) can speed up core FHE functions by over three orders of magnitude.

Posted in: Briefs, Defense, Software, Architecture, Cryptography, Integrated circuits

Using Mathematics to Make Computing on Encrypted Data Secure and Practical

In order to make computing on encrypted data more practical to use and more secure from attack, it is necessary to discover, develop, and understand the mathematics on which it is based and the mathematics that can be used to attack it.

Posted in: Briefs, Defense, Software, Mathematical models, Cryptography, Cyber security

The Effect of Substrate Emissivity on the Spectral Emission of a Hot-Gas Overlayer

Recently, in operando optical investigations of high temperature solid oxide electrochemical cells (SOECs) have gained significant traction with several research groups motivated by a need to directly correlate electrochemical performances of SOECs with their associated and complex electrode processes. These techniques (including Raman spectroscopy, ambient x-ray photoelectron spectroscopy, near-infrared thermal imaging, and Fourier transform infrared emission spectroscopy) have demonstrated a significant advantage over traditional, indirect experimental methods by providing direct, non-invasive information in real time along with high temporal, spatial, and/or molecular resolution.

Posted in: Briefs, Aerospace, Defense, Test & Measurement, Spectroscopy, Emissions, Test procedures, Thermal testing

Process Approach to Determining Quality Inspection Deployment

As new technologies are implemented in manufacturing areas, inspection processes will be affected. Often because product quality has increased or automated inspection equipment has been introduced, the inspection activity may be reduced or eliminated. In many cases a disciplined process is needed to evaluate performance data against risk to determine if this change is warranted.

Posted in: Briefs, Aerospace, Defense, Automation, Manufacturing processes, Quality assurance, Inspections

Experimental Setup to Assess Blast and Penetration- Induced Secondary Debris in a Military Operations in Urban Terrain (MOUT) Environment

As part of Project Agreement on Military Operations in Urban Terrain (MOUT), the US Army Research Laboratory’s (ARL’s) Explosives Effects Branch supported a series of experiments conducted in Meppen, Germany (DEU), to understand loading on personnel protective equipment (PPE) produced during urban weapon attacks. These experiments were conducted by detonating an explosive charge placed on a brick wall to create secondary debris that would impact the US-designed collection medium.

Posted in: Briefs, Aerospace, Defense, Test & Measurement, Fabrics, Foams, Plastics, Impact tests, Protective equipment, Military vehicles and equipment

Non-Contact Circuit for Real-Time Electric and Magnetic Field Measurements

An energized electric power cable generates low-frequency electric and magnetic fields that are related to the voltages and currents. Especially at wavelengths λ>>d, where d is the distance away from an energized conductor and λ is the signal wavelength, we can extract electrical information with quasi-static near-field electric and magnetic field theory and the Principle of Superposition.

Posted in: Briefs, Aerospace, Defense, Test & Measurement, Electric cables, Electromagnetic compatibility, Conductivity

Precision Assembly of Systems on Surfaces (PASS)

Chemiresistors represent a powerful class of chemical sensors that can be readily integrated into any electrical system, can be miniaturized, are readily multiplexed, and take nearly zero-power to operate. One of the greatest limitations to these sensors is a lack of selectivity, which is the electronic equivalent of noise. Interference from large varying background signals, such as humidity, can compromise the sensor signal to a point where there is no useful data. To address this challenge, new ways to integrate molecular constructs into carbon nanotube compositions that produce enhanced selectivity to certain molecules or classes of molecules were investigated to increase the signal to noise level in chemical sensors.

Posted in: Briefs, Aerospace, Defense, Manufacturing & Prototyping, Electrical systems, Sensors and actuators, Humidity, Chemicals, Nanotechnology, Noise

Development of a Novel Electrospinning System with Automated Positioning and Control Software

Electrospinning is a nanofiber fabrication technique that has grown in popularity due to its potential in numerous biomedical applications. The process uses an electrical charge to draw ultrafine fibers from liquid polymer solution to form a non-woven fiber scaffold. The polymer fiber diameters can range from millimeters to as small as nanometers in scale.

Posted in: Briefs, Aerospace, Defense, Manufacturing & Prototyping, Medical equipment and supplies, Fabrication, Fibers, Nanotechnology, Polymers

Advanced Multifunctional Materials for High Speed Combatant Hulls

Currently small boat combatant design focuses primarily on speed and maneuverability. It would be advantageous to expand these capabilities to include reduced radar cross-section, and enhanced survivability to blast and ballistic threats for both the structure and warfighters.

Posted in: Briefs, Aerospace, Defense, Manufacturing & Prototyping, Radar, Crashworthiness, Marine vehicles and equipment, Military vehicles and equipment

Multifunctional Shear Pressed CNT Sheets for Strain Sensing and Composite Joint Toughening

The main goal of this work is to obtain a scientific understanding of the possibilities provided by, and the behavioral features of, a novel type high performance carbon nanotube (CNT) reinforced composite material incorporated in the interfaces of composite laminates and bonded joins with the following two purposes: (a) providing enhancement of the interlaminar fracture toughness and strength and (b) serving as a continuous strain monitoring sensor.

Posted in: Briefs, Aerospace, Defense, Manufacturing & Prototyping, Joining, Coatings Colorants and Finishes, Composite materials, Fatigue, Materials properties, Nanomaterials

Autonomous Underwater Munitions and Explosives of Concern Detection System

The objective of Environmental Security Technology Certification Program (ESTCP) Project MR-201002, Autonomous Underwater Vehicle (AUV) Munitions and Explosives of Concern (MEC) Detection System, was to integrate an untethered and unmanned underwater vehicle with a total field magnetometer for underwater munitions detection and upgrade magnetic noise compensation software to reduce interference from electrical and dynamic influences such as vehicle heading, pitch and roll.

Posted in: Briefs, Aerospace, Defense, Automation, Sensors and actuators, Noise, Hazards and emergency management, Autonomous vehicles, Marine vehicles and equipment

Power-Line UAV Modeling and Simulation

The Army Research Laboratory Power-Line Unmanned Aerial Vehicle (UAV) Modeling and Simulation (ARL-PLUMS) Software Tool allows a user to model, compute, and analyze the quasistatic electric and magnetic fields around alternating current (AC) power lines. ARL-PLUMS comes with an interactive graphical user interface (GUI), which accesses a compute engine to calculate these fields around these lines due to various ground and line geometries and load conditions. ARLPLUMS allows the user to rapidly define all significant model parameters and compute the electric and magnetic fields along a UAV path or in a cutting plane. In addition, a set of false-color plots can be created to show the time-varying nature of the fields as a movie. ARL-PLUMS also comes with an application programming interface (API) for accessing some of these features from MATLAB without using the GUI.

Posted in: Briefs, Aerospace, Defense, Automation, CAD / CAM / CAE, Electric cables, Human machine interface (HMI), Noise, Unmanned aerial vehicles

Design of a Multi-Segmented Magnetic Robot for Hull Inspection

Hull, deck plate, and tank inspection for corrosion, deformation, and fractures is a necessary part of ship maintenance to ensure functional integrity and proper operation of the ship. These inspections are labor intensive, expensive, and often dangerous. A multi-segmented magnetic wheeled robot can assist the surveyors in these tasks.

Posted in: Briefs, Aerospace, Defense, Automation, Maintenance, Repair and Service Operations, Robotics, Vehicle inspections, Marine vehicles and equipment

A Modular Approach to Video Designation of Manipulation Targets for Mobile Manipulators

Currently fielded EOD (explosive ordnance disposal) robots are limited in terms of both mechanical ability and autonomous capabilities when compared to the current state-of-the-art in mobile robotics. To combat this problem the Joint Service EOD Program is developing the Advanced EOD Robot System (AEODRS). AEODRS consists of three system variants that vary in size: small for dismounted operations, medium for tactical operations, and large for base/infrastructure operations. Differing from past EOD UGV development efforts, these robots will be designed under a modular architecture consisting of several capability modules that are to be developed separately.

Posted in: Briefs, Aerospace, Defense, Automation, Architecture, Robotics, Hazards and emergency management, Military vehicles and equipment

Two-Dimensional Distributed Velocity Collision Avoidance

As the number of autonomous vehicles continues to increase for both commercial and military applications, collision avoidance algorithms are of the utmost importance to successfully execute missions in dynamic environments.

Posted in: Briefs, Aerospace, Defense, Automation, Mathematical models, Collision avoidance systems, Autonomous vehicles

Undersea Communications Between Submarines and Unmanned Undersea Vehicles in a Command and Control Denied Environment

Nuclear powered submarines can stay submerged for days at a time and only have to come to periscope depth (PD) for communications and minor house-keeping items. Submarines are completely reliant on satellites for communications and orders from their commanders ashore. A command and control denied environment (C2DE) is an area in which communications are jammed or degraded. There is no technology currently available that allows submarines to conduct communications in a C2DE. The only method currently available is for the submarine to navigate to unaffected waters, conduct all of its communications, and then to travel back to the C2DE, wasting valuable time and possibly compromising the submarine’s mission.

Posted in: Briefs, Aerospace, Defense, Automation, Vehicle networking, Wireless communication systems, Autonomous vehicles, Marine vehicles and equipment, Satellites

Creating Simulated LIDAR Images of Human Poses in a Virtual Laboratory

LIDAR is a partial 3D standoff sensing method that illuminates a target with rotatory or flash laser beams, analyzes the reflected lights, and provides both the distance to the target’s surface and the target’s surface shape. An array of laser reflections can be used to map the facing-side surface of a target object as a partial point cloud. Unlike a 360° surface model generated by a traditional full body scanner, the partial point cloud from a LIDAR is a viewing angle dependent 3D representation of the target shape. The resolution of these maps depends on the density of the laser detector array; a good image of a human may require hundreds of detection pixels to capture enough detail to clearly detect changes in limb positions.

Posted in: Briefs, Sensors, Cartography, Lidar, Security systems, Anatomy, Kinematics, Medical equipment and supplies

Advanced Sensors for Traumatic Brain Injury (TBI)

The objective of this work was to use miniaturized, state-of-the-art pressure/temperature sensors engineered at Lawrence Livermore National Laboratory (LLNL) to measure the immediate increases in intracranial pressure (ICP) combined with longer-term measurements of biological ICP and intracranial temperature. The experience gathered from this work provided valuable data on sensor placement, long-term brain tissue responses to implanted sensors, and sensor capability of dual measurement of biologic ICP and impact pressure transients.

Posted in: Briefs, Sensors, Sensors and actuators, Medical equipment and supplies, Nervous system, Prostheses and implants, Head injuries

Multifunctional Core-Shell and Nano-Channel Design for Nano-Sized Thermosensor

This work focused on developing novel nano-sized thermal sensors based on a multifunctional core/shell and nano-channel design that can be used to measure temperature and retaining thermal history of the biological agents experienced during the testing of agent-defeat weapons.

Posted in: Briefs, Sensors, Sensors and actuators, Thermal management, Nanotechnology, Military vehicles and equipment