MEMs

Cooperative Single-Antenna Node Networks

Future tactical networks will be complex, with severe constraints on energy and bandwidth, operating in dynamic and unpredictable environments. By exploiting the broadcast nature of the wireless medium and spatially dispersed nodes, some of these advantages can be realized through cooperation among single-antenna nodes in a network.

Posted in: Briefs, Electronics & Computers, Antennas, Telecommunications systems, Reliability, Military vehicles and equipment
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Using Real-World Methodologies to Calculate SSD Usable Life

With more embedded systems using SSDs in critical applications, designers are now asking the question, “How long will this SSD last in my application?” To help answer this pressing question, it is important to review the recent changes in NAND flash technology.

Posted in: Application Briefs, Application Briefs, Embedded Technology, Board-Level Electronics, Electronics & Computers, Computer software / hardware, Life cycle analysis
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Middleware Offers Integration Framework for Dynamic UAV Applications

Unmanned Aerial Vehicles (UAVs) like the MQ-1 Predator have excelled in the theaters of war in which they have been deployed. However, the ability of those controlling the UAV to conceive of new missions for the Predator and other deployed UAVs in the field has led to the U.S. Air Force recognition that the fundamental architectural approach to development of complete Unmanned Aircraft Systems (UASs), including ground stations and other elements, has to put integration capability front and center as a key design issue.

Posted in: Articles, Aerospace, Architecture, Systems engineering, Military aircraft, Unmanned aerial vehicles
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Interaction Methods for Virtual Reality Applications

The potential of Virtual Reality (VR) technology has not been fully realized because the user interfaces are not designed to effectively support the user. One of the most critical interface aspects is the possibility to interact with the system within the virtual environment. The initial idea of optimizing the user interaction was to transfer the interaction that occurs in the real world as accurately as possible into the VR environment. In this case the user, theoretically, would have no problems interchanging between the two worlds.

Posted in: Articles, Aerospace
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Detector Module for Testing Silicon Carbide Semiconductor Devices

Long-term stress testing of silicon carbide (SiC) semiconductor devices is required to determine suitability for power electronics applications. During testing, preventable catastrophic failures can occur due to drift in steady-state operation or transients that shift the device outside of its safe operating range. Both steady-state and transient drift are easily monitored values including temperature, on-state resistance, voltage, and current, as well as others. By measuring and reacting to shifts in these values, device damage can be minimized.

Posted in: Briefs, Physical Sciences, Power electronics, Semiconductor devices, Fatigue, Silicon alloys, Test equipment and instrumentation
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Advanced Lithium Ion Systems for Military Vehicles

The higher energy and power density of Li-Ion battery technology offers a significant reduction in the weight and volume for hybrid electric vehicle (HEV) battery systems compared to lead acid and nickel metal hydride technologies. Saft’s High Power Li-ion battery technology has demonstrated specific power of over 6,000 W/kg under continuous discharge, and a pulse discharge of 8,000 to 12,000 W/kg.

Posted in: Briefs, Physical Sciences, Lithium-ion batteries, Hybrid electric vehicles, Military vehicles and equipment
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MEMS-Based Optical Limiter

Protecting optical sensors and detectors against excessive input signals is not only important for dealing with unintentional overloads, but also central for protecting sensors against intentional high-intensity sources such as flares or laser beams directed as countermeasures against the sensor system. In prior work, a microelectromechanical system (MEMS)-based, all optically driven deformable mirror was designed and fabricated. In this work, an optical limiter using this optically addressed, deformable mirror is proposed and designed.

Posted in: Briefs, Physical Sciences, Mirrors, Microelectricmechanical device, Optics, Sensors and actuators
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Reducing Thicknesses of PbZrₓTi₁₋ₓO₃ Films in Capacitors

A document describes experiments performed to determine effects of reducing the thicknesses of films of lead zirconate titanate (PbZrxTi1-xO3, wherein 0<x<1) used as ferroelectric dielectric layers in some capacitors. The fabrication of specimen capacitors for the experiments involved numerous steps, including spin-coating of PbZrxTi1-xO3-precursor sol-gel solutions onto bottom Pt electrode layers on silicon substrates, heat treatments to covert the sol-gel coats to PbZrxTi1-xO3, and deposition of top Pt electrode layers on the PbZrxTi1-xO3 layers. Various spin rates and solution compositions were used to obtain various PbZrxTi1-xO3- film thicknesses and compositions. Current responses of specimens to applied voltage waveforms were measured to characterize the specimens in terms of capacitance, hysteresis, and polarization. It was concluded that thicknesses of PbZrxTi1-xO3 films could be reduced to between 1,800 and 2,200 A while retaining ferroelectric performance adequate for a proposed development in which nanoelectromechanical switches containing PbZrxTi1-xO3 films would be integrated with complementary metal oxide/semiconductor transistors. One of the sol-gel solutions, characterized by x = 0.45 and a molarity of 0.367, was found to be the most promising for further work to improve performance at thicknesses < 1,800 A.

Posted in: Briefs, Physical Sciences, Capacitors, Transistors, Fabrication, Ferrous metals and alloys, Silicon alloys
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Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical Power

Several attractive features of thermo-electric (TE) technology include no moving parts, light weight, modularity, covertness, silence, high power density, low amortized cost, and long service life with no required maintenance. Many of the potential uses for mounted/ dismounted power, such as recharging batteries, are therefore ideal for TE technologies. However, these applications will require more interconnected, smaller-scale modular devices than are currently available. Most commercial off-the-shelf (COTS) TE devices are optimized for cooling, not for generating power, so new device structures with materials and geometries better optimized for power generation are needed for broader use of TE technologies.

Posted in: Briefs, Manufacturing & Prototyping, Architecture, Fabrication, Electro-thermal engines, Test procedures
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Manufacturing Cylindrical Parts Using Deep Draw Technology

In applications where product performance is mission critical, commercial, military, and aerospace companies require technology to manufacture deep- drawn cylindrical product components. Conventional production alternatives such as impact, spinning, and supplemental annealing processes often do not deliver reliable results for certain applications.

Posted in: Briefs, Manufacturing & Prototyping, Molding, Production engineering, Parts
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