Tech Briefs

Templated Synthesis of Aluminum Nanoparticles for Stable Energetic Materials

Reactive nanoparticles as energetic materials have received much recent attention for a variety of existing and/or potential applications. Among more extensively investigated are nanosized (sub-100-nm) aluminum (Al) particles. Their large specific surface area and energy density, when coupled or mixed with oxidative species, make them unique combustible additives in propellant formulations. Nanoscale Al particles are also studied as high-capacity hydrogen storage materials. Therefore, significant effort has been made in the development of synthetic methodologies for Al nanoparticles of desired properties.

Posted in: Briefs, Materials, Hydrogen storage, Propellants, Fabrication, Aluminum, Nanomaterials

Performance and Operability of a Dual-Cavity Flame Holder in a Supersonic Combustor

Supersonic combustion has been of interest for many years in order to support future Air Force hypersonic missions. The current generation of hydrocarbon-fueled scramjet combustors typically requires a flame-holding device to facilitate flame ignition and stable combustion. The amount of time available for fuel injection, fuel-air mixing, and combustion is very short — on the order of 1 millisecond. This short dwell time, along with the relatively long ignition delay times of hydrocarbon fuels, makes the flow path and flame holder design extremely important. This study investigates the perormance and operability of using a symmetric dual-cavity flame holder flow path to stabilize and enhance supersonic combustion.

Posted in: Briefs, Physical Sciences, Hydrocarbons, Scramjet engines, Performance tests, Hypersonic and supersonic aircraft, Military aircraft

Gesture-Directed Sensor-Information Fusion Gloves

Current chemical-protection gear for warfighters on the ground inhibits electronic communication via keyboards, cell phones, and remote-control devices. To improve communications capabilities for the warfighter wearing protective gear in hazardous environments, a series of eGloves has been developed with a view toward freeing the warfighter of the need to type on a keyboard while wearing a Mission-Oriented Protective Posture (MOPP) suit. The eGloves can help the warfighter transmit gestures with the hands and fingers from within the protective gear, or they can be used to transmit encoded ASCII characters.

Posted in: Briefs, Physical Sciences, Communication protocols, Human machine interface (HMI), Product development, Protective clothing, Military vehicles and equipment

GigE Advanced Imaging Sensor

The Wide-Field Dynamic Range (WFDR) camera is a high-sensitivity, wide-field-of-regard sensor of importance to future military surveillance and survivability systems. It is intended to be used in harsh, noisy military platforms with multiple camera streams simultaneously gathered. By developing a Gigabit Ethernet (GigE) video transport solution for multiple cameras with low latency and high data reliability, a flexible processing architecture will be developed that allows optimization of processor throughput for real-time imaging in defense applications.

Posted in: Briefs, Physical Sciences, Architecture, Optics, Sensors and actuators, Surveillance, Military vehicles and equipment

Liquid-Crystal-Based Optical Phased Array for Steering Lasers

A paper describes the basic design and concepts of tunable liquid-crystal polarization gratings with a nematic liquid crystal (LC) optical phase plate, with a large, continuous in- plane gradient that is variable, and its application to a beam steering device with high efficiency.

Posted in: Briefs, Physical Sciences, Calibration, Lasers, Waveguides

Channel Modeling for a Wireless Transmission System

A wireless transmission system provides high-quality video transmission over severely impaired wireless links between nodes that are connected within airborne networks. The target bit rate for the proposed video communication can be in the range between 24 Kbps and 384 Kbps with relatively high visual quality. However, the system may operate at extreme low bit rates down to 10 Kbps and at high bit rates up to 1.5 Mbps. To accommodate the large range of the data rate for heterogeneous wireless links and devices, the H.264 SVC standard for video coding and decoding was adopted.

Posted in: Briefs, Information Technology, Mathematical models, Cryptography, Imaging, Wireless communication systems

Power for Micro Autonomous Systems

The Micro Autonomous Systems and Technology (MAST) Collaborative Technology Alliance (CTA) has been initiated to spur basic research in small autonomous robots, particularly in four main areas: Microsystem Mechanics, Autonomous Processing, Micro electronics, and Integration. In order to focus its efforts, the Army proposed multiple scenario missions of increasing difficulty to work towards: small unit building search (flat, straight walls, no wind, etc.), a small unit cave search (potential for wind gusts, no regular surfaces to use as reference points), and perimeter defense (longer required mission time, and range and potentially harsh environments). The size ranges considered were defined as “palm-size” and below, where no lower limit was specified.

Posted in: Briefs, Physical Sciences, Microelectricmechanical device, Robotics