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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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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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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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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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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 thermomechanical 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, microstructural, 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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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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