MEMs

Computational Photonics in Laser Communications Through Clouds

This work explored the concept of creating a partially coherent laser beam consisting of an array of spatially overlapping or separated Gaussian beams with possible individual control of each individual emitter’s wavelength. The idea was to test whether such a transmitter array could propagate more effectively through weak or strong atmospheric turbulence. It was proposed that a versatile, multi-wavelength, multi-emitter configuration could be realized via an array of optically pumped, vertical external-cavity surface emitting semiconductor lasers (VECSELs).

Posted in: Briefs, Photonics, Lasers, Semiconductors, Test procedures, Turbulence
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Fire Resistance of Geopolymer Concretes

Geopolymer concrete has been proposed as an alternative to Portland cement concrete in applications requiring high degrees of fire resistance, because the intrinsic chemistry of the geopolymer binder does not require the retention of water or hydration within gel phases to maintain structural integrity of the binder. Portland cement concrete contains a high level of chemically bound water, which is essential to the gel binder structure, and which is lost upon heating to several hundred degrees Celsius, whereas the water present within a geopolymer concrete is overwhelmingly present in pores and is not an essential part of the strength-generating phases. However, predictions of geopolymer concrete fire performance have up to this time been based on small-scale laboratory testing (usually on paste or mortar specimens), rather than the study of large concrete sections, which provides significance to this work.

Posted in: Briefs, Materials, Composite materials, Heat resistant materials, Polymers, Fire
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Tomographic Electrical Resistance-Based Damage Sensing in Nano-Engineered Composite Structures

Advanced composite materials are increasingly replacing metals in the aerospace industry as they offer weight-saving improvements such as high specific strength and stiffness, while providing resistance to fatigue and corrosion. Traditional advanced composites, however, exhibit significantly reduced electrical and thermal conductivity relative to metals, and matrix-rich regions at ply interfaces result in relatively poor interlaminar properties. Additionally, composites that have sustained damage often have non-visible or barely visible damage, complicating damage assessment. Recent efforts to address the limitations of advanced composites include the incorporation of carbon nanotubes (CNTs) to take advantage of intrinsic and scale-dependent properties of these nanostructures.

Posted in: Briefs, Materials, Aircraft structures, Composite materials, Conductivity, Nanomaterials
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Uncooled Tunable LWIR Microbolometers

Uncooled infrared detectors have significant potential capabilities that have been little explored. Micro-machined uncooled detectors with tunable spectral characteristics across the long-wave infrared (LWIR, λ~8-12 μm) have been developed. In the middle wavelength infrared (MWIR) and LWIR regions, the fabrication of Fabry-Perot filters is more complex because the optical materials must be infrared-compatible and the layer thicknesses must be larger. It is very difficult to build filters for uncooled LWIR thermal detectors, which has limited previous researchers to demonstrations of discretely tunable 2- or 3-color thermal detectors rather than continuously tunable ones.

Posted in: Briefs, Physical Sciences, Architecture, Sensors and actuators, Thermal testing
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Fluid Helmet Liner for Protection Against Blast-Induced Traumatic Brain Injury

An Advanced Combat Helmet liner design uses the novel idea of including filler materials inside channels in the liner. An energy-absorbing foam was selected for the main liner structure, and several filler material candidates of widely varying properties are being considered. To date, material has been evaluated both experimentally and numerically. Numerical studies will include coupled simulations with a detailed finite element head model, providing insight into the effect of the new liner on the brain’s response to a blast wave impact.

Posted in: Briefs, Physical Sciences, Finite element analysis, Foams, Head injuries, Protective equipment, Military vehicles and equipment
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Performance of Steel Stud Walls Subjected to Blast Loads

Construction trends have brought about an increase in the use of cold-formed steel studs in Air Force facilities. These steel stud walls have significant potential for mitigating large blast events. The current state of steel stud research, however, has not addressed all the variables that can influence the behavior of typical wall systems. As a result, there is a research gap that exists in the blast-resistant design of conventional steel stud wall systems.

Posted in: Briefs, Physical Sciences, Materials properties, Steel, Protective structures, Construction vehicles and equipment
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12-Volt System with Mini-ITX Motherboard

ITOX (East Brunswick, NJ) has partnered with Systium® Technologies to introduce the Model 132 “mini” series 12-volt system utilizing the ITOX NP101-D16C Mini-ITX motherboard. The Systium Model 132 “mini” series system platform is designed for cost-sensitive applied computing and x86 embedded systems applications requiring high-quality, long-life modular computing solutions. This is particularly applicable to medical electronics, industrial control, security and surveillance, telecommunications, ATM/POS, digital signage, gaming, and kiosk systems fields. The motherboard utilizes the 45nm 1.6 GHz Intel® AtomTM N270 processor with Intel 945GSE Express chipset and ICH7M I/O controller hub. The platform exhibits a thermal design power of less than 15 watts, delivering higher performance-per-watt than previous platforms. A single 12 VDC power input also reduces overall system configuration and operating costs.

Posted in: Products, Products, Embedded Technology, Board-Level Electronics, Electronics & Computers
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DB9 Adapter

Sealevel (Liberty, SC) has developed a compact, rugged DB9F-to-5 screw terminal block adapter that allows users to connect their field wiring to DB9 connectors on USB Serial adapters, Ethernet Serial servers, and other Sealevel RS-485 products with a DB9M connector. It is RoHS compliant, works with 2- and 4-wire RS-485 networks, and can be secured to the serial port with thumbscrews to prevent accidental disconnection. The screw terminals accept 16-28 AWG gauge wiring.

Posted in: Products, Products, Embedded Technology, Board-Level Electronics, Electronics & Computers
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Embedded Virtualization Manager

TenAsys® Corporation (Beaverton, OR) is now shipping eVMTM for Windows®, an embedded virtualization manager software product that enables different real-time operating systems (RTOSes) to run alongside Windows on the same multi-core processor platform. Using eVM, applications that have been developed for standalone RTOSes such as QNX®, VxWorks®, and Windows CE, can be run on multi-core Windows platforms with full native performance. eVM utilizes hardware-assisted features built into Intel® processors to allocate hardware resources and ensure that time-critical I/O processes are not interrupted.

Posted in: Products, Products, Board-Level Electronics, Electronics & Computers
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Rugged Waterproof Computer

SmallPC.com (Burlington, Ontario, Canada) has released its latest waterproof computer. The SC240ML is designed and tested for reliable operation in the most extreme wet, dirty, and dusty environments, hot or cold. The SC240ML’s rugged aluminum chassis uses a unique heat pipe

assembly along with a set of specialized I/O connectors and cables to provide a high performance computer that is sealed to IP67/NEMA 6 standards. The operating temperature range

is -20°C to +60°C.

Posted in: Products, Products, Electronics & Computers
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