Tech Briefs

Development of Adaptive and Reflective Middleware

A report describes Phase II of the Adaptive and Reflective Middleware Systems (ARMS) program, which was focused on developing an adaptive and reflective network Quality-of-Service (QoS) infrastructure for the Total Ship Computing Environment (TSCE). Conceived for the next generation of Navy surface ships, the TSCE is associated with a computing architecture characterized by modularity, extensibility, scalability, and amenability to upgrading of all software and hardware systems. A major feature of the ARMS approach is the use of a bandwidth broker that provides admission control and leverages differentiated-services and class-of-service functionalities of high end routers and switches in order to guarantee end-to-end QoS in a heterogeneous computing environment. Building upon the Phase I product, the Phase II development (1) provides continued assurance of network QoS for mission- critical tasks in the presence of single mode faults and such catastrophic faults as the loss of an entire data center, and (2) improves timely adaptation to network performance using probes and instrumentation to measure delay. The ARMS development also raises the level of abstraction in the use of model-driven development software tools for configuring, deploying, and achieving QoS in distributed real-time embedded systems.

This work was done by Balakrishnan Dasarathy of Telcordia Technologies, Inc. for the Defense Advanced Research Projects Agency.

Posted in: Briefs, Information Technology
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Multiscale Virtual Design and Testing of Materials

Progress has been made in research on several fronts in an effort to develop computational simulation capabilities for use in virtual design and testing of advanced structural materials. It is envisioned that the capabilities will be embodied in a coherent set of methods, software to implement the methods, and advances in the fundamental understanding of many issues in the thermo-mechanical performance of materials. It is further envisioned that the methods and software will be organized into a hierarchy (see figure) corresponding to a hierarchy of spatial scales from electronic through atomic, mesoscale, micro-structural, and continuum to macrostructural, and that there will be seamless coupling of information from each scale to the next larger scale. A secondary objective of this research and development effort is to provide direct simulation output at each level of the hierarchy for investigating specific phenomena at the corresponding spatial scale. For the purposes of demonstrating the capabilities and providing specific focus for the overall research, it is intended to predict nano-, micro-, and macroscopic degradation of aluminum and titanium alloys under fatigue loading and in a corrosive (oxidative) environment and as a function of temperature.

Posted in: Briefs, Information Technology, Design processes, Simulation and modeling
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Life Tests of a Microwave MEMS Capacitive Switch

Life tests have demonstrated the longevity of an electrostatically actuated capacitive switch of a microelectromechanical systems (MEMS) type suitable for handling radio signals having frequencies of multiple gigahertz. The tests were performed to contribute to understanding of factors that affect the reliability of MEMS switches in general and of how improvements in designs and materials can increase operational lifetimes of MEMS capacitive switches. The tests were based partly on the concept that data obtained in monitoring both high-speed and low-speed switching characteristics provide valuable insight into quantifying the lifetime properties of the switches and enable estimation of switching lifetimes under a variety of operating conditions.

Posted in: Briefs, Electronics & Computers, Microelectricmechanical device, Switches
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Measuring Corrosion-Related Properties of Coupled Metals

Amethod and apparatus have been conceived for using electrochemical impedance spectroscopy (EIS) for determining rates of corrosion of coupled metals. EIS has been used heretofore for determining rates of corrosion of single metals. However, many structures used in corrosive environments include different metals in electrical contact. Moreover, the concept of using a sacrificial metal to suppress or reduce the corrosion of another metal is applied in some structures. The coupling of two different metals can affect the rates of corrosion of both. Hence, there is a need to extend EIS to coupled metals.

Posted in: Briefs, Physical Sciences, Spectroscopy, Corrosion, Metals
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Scaling of Flight Tests of Unmanned Air Vehicles

A program of research has addressed a methodology of scaling of flight tests of unmanned air vehicles (UAVs) intended primarily for military use in observing and/or attacking targets on the ground. The main goal of this research is to make it possible to design a model UAV that is suitable for evaluating the performance of a given real UAV or family of UAVs. This research also demonstrates the use of results of computational simulations and ground hardware experiments on models of vehicles other than UAVs to predict performances of UAVs prior to conducting flight tests.

Posted in: Briefs, Physical Sciences, Flight tests, Unmanned aerial vehicles
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Small-Scale Combustion-Chamber Testing Facility

A small-scale combustion-chamber testing facility has been designed and partly built for use in evaluating advanced combustor designs for future gas turbine engines. The specific model combustor for which the facility was designed is an approximation of a planar section of an ultra-compact combustor (UCC). In the full-scale UCC (Figure 1), vanes in an annular cavity are positioned and oriented to cause the combustion gases to flow in a spiral pattern and the resulting centripetal acceleration in the cavity is utilized to increase the speed of combustion and thereby make it possible to design the combustion chamber to be shorter than would otherwise be necessary. In the model combustor, the spiral aspect of the flow is approximated by means of a small flow of air directed perpendicular to a main flow. The design of the facility and the model combustor provides access for off-axis optical (including visual) observation and measurement of cavity-vane interactions. The facility can also be used to test many other combustor models.

Posted in: Briefs, Manufacturing & Prototyping, Combustion chambers, Test facilities
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Interactive DataWall

The Interactive DataWall (IDW) is a computer-driven, high-definition display, large enough to be visible simultaneously to multiple observers, that presents information from multiple sources and exploits advanced techniques of human/computer interaction and data fusion. The IDW originally was intended for collaborative use by a group of Air Force decision-makers who must consider large amounts of dynamic information (e.g., information pertinent to targeting during battle). Sources of displayed and otherwise utilized information can include sensors on terrestrial vehicles, sensors aboard satellites, databases, and video feeds from remote locations.

Posted in: Briefs, Electronics & Computers, Data acquisition and handling, Human factors, Displays, Collaboration and partnering
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Miniature Semiconductor Diodes as Pumps and Motors

Experiments have shown that when a miniature semiconductor diode floats in an aqueous solution and an alternating electric field is applied, (1) the diode rectifies the alternating potential induced between the electrodes, and (2) the resulting pulsating DC potential gives rise to an electro-osmotic flow in the vicinity of the diode and associated force that orients the diode along the electric-field direction, and propels the diode through the water. The propulsive force on the diode is along the electricfield direction and can be toward the cathode or the anode end, depending on the precise nature of the surface charge on the diode and the chemical composition of the solution. It has been proposed to exploit this phenomenon in developing microscale and nanoscale pumps and motors for diverse purposes. The proposal is not as radical as it might first seem: Electro-osmosis in applied DC electric fields has been used to pump liquids in microfluidic devices.

Posted in: Briefs, Electronics & Computers, Semiconductor devices, Pumps
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Optical-Fiber Infrasound Sensors

Optical-fiber infrasound sensors (OFISs) are being developed for detecting acoustic pressures in the frequency range from a few millihertz to a few hertz. As explained below, these sensors were conceived to overcome some of the limitations of prior infrasound sensors based on pipe filters connected to microbarographs.

Posted in: Briefs, Photonics, Fiber optics, Sensors and actuators, Acoustics
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Study of Membrane Optics for Lightweight Space Telescopes

Astudy has been performed to establish a foundation for the analysis, design, and further development of inplane- actuated deformable membrane mirrors for lightweight spaceborne telescopes. It is envisioned that the telescopes, having typical mirror diameters of 20 m or larger, would be stowed compactly for launch and transport, then deployed in orbit around the Earth for use in surveillance of the Earth and in exploration of deep space.

Posted in: Briefs, Photonics, Mirrors, Optics, Test equipment and instrumentation
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Implantable Electrochemical Sensors for Metabolic Monitoring

Arrays of electrochemical sensors that include specially coated (as described below) gold electrodes on flexible polyimide sheets have been fabricated and tested in a continuing effort to develop biocompatible, surgically implantable electrochemical-sensor arrays for continuous measurement of concentrations of analytes that play major roles in human and animal metabolism. The effort thus far has been oriented particularly toward developing sensors for monitoring one analyte — glucose — to enable improved treatment of diabetic patients. It is planned to extend this effort to the fabrication and testing of sensors for monitoring lactate and pyruvate and, eventually, to implement the concept of a single array that contains sensors for monitoring glucose, lactate, and pyruvate.

Posted in: Briefs, Medical, Sensors and actuators, Medical, health, and wellness
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Portable Simulator for Training in Robot-Assisted Surgery

Aportable apparatus is being developed as a means of training surgeons in robot-assisted surgery, including laparoscopic and other forms of minimally invasive surgery. The apparatus can be characterized as a virtual reality system that includes not only a computer and a visual display subsystem, but also an electromechanical subsystem with which a surgeon in training can interact as though interacting with a console of the type used to control a laparoscopic, endoscopic, or other surgical robot.

Posted in: Briefs, Medical, Simulation and modeling, Surgical procedures, Robotics
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Imaging System for Characterizing Materials and Processes

Ahigh-performance digital imaging system has been assembled to provide enhanced capabilities for characterizing materials and processes. Highspeed imaging is needed for observation and analysis of such fast dynamic processes as impact fracture (including ballistically induced fracture) in advanced composite materials, dynamic deformation of materials, and hydrodynamic instabilities in jets. Because these dynamic processes occur at diverse temporal and spatial scales, there is a need for an imaging system that can operate at correspondingly diverse frame rates, spatial resolutions, and magnifications, and that is capable of recording various numbers of image frames.

Posted in: Briefs, Physical Sciences, Imaging
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Progress in Research on Bacteria-Powered Motors

Progress has been made on several fronts in research on biomotors and especially on microscopic motors powered by bacteria. The progress consists mostly of advances in the art of attaching motile bacterial cells to surfaces in specific, pre-designed microarrays.

Posted in: Briefs, Physical Sciences, Bacteria
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Fabrication of Lightweight Armored Doors for HMMWVs

A document describes a concept for fabricating lightweight armored doors for the Army’s high-mobility multipurpose wheeled vehicles (HMMWVs). Essentially, the concept is to reinforce high-hard (HH) steel armored doors used on some HMMWVs with a laminated, woven, high-tensile-strength glassfiber/ polyester-matrix composite that has performed well as armor material in previous military applications. A fabrication procedure for implementing the concept, described in the document, can be summarized as follows:

Posted in: Briefs, Manufacturing & Prototyping, Doors, Fabrication, Composite materials, Glass fibers, Steel, Military vehicles and equipment
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AFRL’s Demonstration and Science Experiments Mission

A document describes the Air Force Research Laboratory's Demonstration and Science Experiments (DSX) mission, dedicated to research needed to advance the ability to operate spacecraft in the harsh radiation environment of medium earth orbit (MEO). The DSX spacecraft, to be launched in late 2009 into an orbit ranging in altitude from 6,000 to 12,000 km, is designed to carry instruments pertinent to studies in three categories:

Posted in: Briefs, Physical Sciences, Research and development, Spacecraft
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Dense Functionalized-Nanowire Biosensor Arrays

Progress has been made in the development of compact sensor arrays containing molecular electronic devices for detecting molecules of interest (especially biomolecules) with high sensitivity and selectivity. As described in somewhat more detail below, the sensory devices in these arrays are based on chemically functionalized semiconductor nanowires. Because of the small sizes of nanowire-based devices, these arrays could be extremely dense, enabling simultaneous detection of multiple molecular species of interest. In addition, in some cases, it should be possible to extend the limits of detectability to quantities as small as a single molecule.

Posted in: Briefs, Electronics & Computers, Semiconductor devices, Sensors and actuators
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Nanowire-Based Chemical and Biological Sensor Arrays

Acontinuing effort that supplements and complements the one summarized in the immediately preceding article is dedicated to the development of nanowire-based sensor arrays, with emphasis on maximizing the utility of such arrays for real-time sensing of molecular species associated with chemical and biological threats. Like the sensors described in the immediately preceding article, most of these sensors are based on chemically functionalized semiconductor nanowires that are parts of fieldeffect transistors. In addition, some of these sensors are based on piezoelectric nanowire resonators.

Posted in: Briefs, Electronics & Computers, Sensors and actuators, Biological sciences, Chemicals, Nanotechnology
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Improved Magnetic Sensor Based on Giant Magneto-Impedance

A low-power, highly stable electronic sensor circuit for measuring a small change in the ambient magnetic field with high sensitivity exploits the giant magneto-impedance (GMI) effect, in which the radio-frequency (RF) impedance of a fiber made of a suitably formulated material varies with the externally generated magnetic field to which it is exposed. The GMI effect has been observed in fibers thinner than a human hair made of amorphous (in the sense of lacking crystalline structure) alloys of cobalt, iron, silicon, and boron.

Posted in: Briefs, Electronics & Computers, Sensors and actuators, Fibers
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Miniature Hyperspectral Sensors for Imaging on Small UAVs

As unmanned vehicles get smaller and smaller, operational expectations and mission objectives demand a much broader array of platform capabilities — a necessity even with reduced payloads requiring less weight, smaller size, and less power consumption. An interesting dichotomy exists between the need for increasing amounts of valuable information and the operational ability to capture and synthesize this information in real time.

Posted in: Briefs, Photonics, Imaging, Sensors and actuators, Unmanned aerial vehicles
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Solid-State Viscosity Sensors For Military and Aerospace Applications

Embedded OEM application markets such as the military and aerospace industries are experiencing a growing demand for sensors that provide instantaneous and continuous process control and machine health information. For a large segment of these industries, fluid viscosity is the key physical parameter that can assist in final process control and machine diagnostics. To that end, it is imperative that a solid-state chip be cost-effective and provide the functionality and scalability that is demanded.

Posted in: Briefs, Physical Sciences, Sensors and actuators
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Progress in Canted Sector Antennas and Non-Periodic Arrays

Progress has been made in a continuing effort to develop low-geometricprofile, wide-frequency-band microwave antennas intended for incorporation into wide-band aperiodic arrays for use in high-speed communications. The effort has produced improved designs for canted sector antennas, cost-effective approximations of random arrays of such antennas, and software for simulating the performances of such antennas and arrays.

Posted in: Briefs, Electronics & Computers, Antennas, Telecommunications
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Photonic Analog-to-Digital Converters

Early steps have been taken toward the development of analog-to-digital converters (ADCs) that would incorporate photonic quantizers based on the technology of InP semiconductors. These photonic ADCs are intended to overcome the sampling speed and temporal resolution limitations of state-of-the-art all-electronic ADCs, so that outputs of radar and other sensor systems at frequencies as high as tens of gigahertz could be sampled directly, without need for analog signal processing to effect down-conversion in frequency prior to sampling.

Posted in: Briefs, Electronics & Computers, Electronic equipment, Radar, Sensors and actuators, Semiconductors
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Photonic Analog-to-Digital Converters

Early steps have been taken toward the development of analog-to-digital converters (ADCs) that would incorporate photonic quantizers based on the technology of InP semiconductors. These photonic ADCs are intended to overcome the sampling speed and temporal resolution limitations of state-ofthe- art all-electronic ADCs, so that outputs of radar and other sensor systems at frequencies as high as tens of gigahertz could be sampled directly, without need for analog signal processing to effect down-conversion in frequency prior to sampling.

Posted in: Briefs, Photonics, Electronic equipment, Radar, Sensors and actuators, Semiconductors
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Photonic-Crystal-Based Devices for Commercial Applications

Several analog-to-digital converter (ADC) devices and part of a multispectral receiver have been designed, fabricated, and tested to demonstrate their feasibility as part of an effort to establish the organizational and technological foundation for development of photonic-crystal-based devices for commercial and military applications. Also known as photonic-band-gap devices, photonic crystals contain periodic structures having feature sizes in the submicron range — less than the wavelengths of light that the devices are intended to handle. Photonic crystals can be fabricated by techniques used in the integrated-circuit and microelectromechanical systems (MEMS) industries.

Posted in: Briefs, Photonics, Optics
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Infrared Data Link Using an MQW Modulator on a Retroreflector

A n infrared data link between a ground station and a small uninhabited helicopter in flight has been demonstrated in an effort to develop a type of system for free-space optical communication between (1) a larger and relatively stationary platform, and (2) a smaller and relatively mobile platform. In a system of this type, rather than using laser transmitters with their associated gimbaled telescopes and pointing/tracking subsystems on both platforms, one uses only a single such laser transmitter on the larger platform (in this case, the ground station). The single laser transmitter is capable of tracking the smaller platform (in this case, the helicopter) and transmitting data to the smaller platform in the conventional way via modulation of the outgoing laser beam. The field of view of the receiver on the smaller platform is wide enough to capture the laser beam, without need for a large receiving telescope and its aiming subsystem. For transmitting data from the smaller to the larger platform, a large fraction of the laser power incident on the smaller platform is modulated and retroreflected to the larger platform, by means of an InGaAs-based multiple-quantum-well (MQW) light modulator on a cornercube retroreflector (see Figure 1).

Posted in: Briefs, Photonics, Data exchange, Optics, Rotary-wing aircraft
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Self-Lubrication of Hot YSZ-Ag-Mo Nanocomposite Coatings

An experimental study has been performed to learn about the physical and chemical mechanisms of self-lubrication of coatings that comprise nanostructured composites of yttria-stabilized zirconia (YSZ), silver, and molybdenum. These and other YSZ-based nanocomposite coatings have received increasing attention in recent years because they offer a combination of hardness, toughness, resistance to wear, and low-friction C properties that make them attractive for reducing wear and friction and increasing the lifetimes of hot, sliding components of mechanical systems. In addition to the excellent mechanical and thermal stability of the basic YSZ ceramic material, the nanocomposite structures of these coatings, consisting of combinations of amorphous and crystalline phases, provide a “chameleon” surface adaptation, in which different phases turn into lubricants in response to different test environments, contact loads, sliding speeds, and temperatures. Moreover, proper sizing of nanocrystalline grains can restrict crack sizes and create large volumes of grain boundaries, thereby increasing the toughness and contact-load-bearing capabilities of these coatings.

Posted in: Briefs, Materials, Lubricants, Coatings Colorants and Finishes, Composite materials, Nanomaterials, Wear
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Hybrid Three-Axis Vibration Reducers

Hybrid (passive/active) devices have been developed to reduce the magnitudes of possibly threedimensional vibrations coupled from vibrating equipment on platforms to bases that support the platforms. These hybrid devices are three-axis generalizations of singleaxis hybrid vibration reducers developed and reported previously. Each hybrid device includes rubber passive vibration-isolator pads, piezoelectric actuators, optional piezoelectric force sensors, and accelerometers. Each device operates in conjunction with a computer and control-and-actuation circuitry, which process accelerometer readings using feedforward and/or feedback control laws to excite the piezoelectric actuators with signals having amplitudes and phases chosen to minimize acceleration of the base.

Posted in: Briefs, Mechanical Components, Vibration
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Some Advances in Reducing Drag and Suppressing Convection

Theoretical and computational research has yielded some advances in the art of designing active feedforward and feedback controllers to suppress thermal convection and reduce drag (by suppressing turbulence) in boundary-layer flows. The advances include (1) improved means for designing reduced-order (and, hence, computationally more efficient) controllers and (2) discovery of a previously unknown phenomenon that could be exploited for feedforward control to reduce drag.

Posted in: Briefs, Mechanical Components, Electronic control systems, Drag
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Autonomous Vehicles Would Learn by Mimicking Human Drivers

A program initiated by the Defense Advanced Research Projects Agency (DARPA) and now also pursued by other agencies called “Learning Applied to Ground Robots” (LAGR), is developing control algorithms that would enable a robotic land vehicle, robotic underwater crawler, or other similar autonomous mobile robot to traverse terrain safely. Among the algorithms needed are navigation algorithms for finding and then following a safe path across terrain from a starting or current position to a destination.

Posted in: Briefs, Information Technology, Vehicle drivers, Robotics, Autonomous vehicles
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