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Digital Switch Matrices

The Electronics Group of Crane Aerospace & Electronics, Redmond, WA, has released its Model 1130 and Model 1120 digital switch matrices that are configured to accommodate up to 144 inputs and 144 outputs that can be distributed among clock and data signals. They provide full fan-out operation, allowing each input to be routed to any or all outputs simultaneously. They are also nonblocking, meaning that any number of input and output combinations can be connected. These devices are suitable for large data routing installations.

Posted in: Products
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The Ballistic Missile Defense System: An Integrated Approach to Global Defense

Although the end of the Cold War signaled a reduction in the likelihood of global nuclear conflict, the threat from ballistic missiles has grown steadily as sophisticated missile technology becomes available on a wider scale to countries hostile to the U.S. and its allies.

Posted in: Articles, Aerospace
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Data-Centric Distributed Application Architecture for Shipboard Systems

System architects design distributed applications leveraging computer resources connected by a network infrastructure: CPU-intensive tasks may be located on powerful core servers; application-data storage may be managed by specialized database servers; and data-collection, actuation, and user interaction may occur on nodes located at the edge of the network. The architecture must accommodate coordination of the distributed resources as well as ensuring that the necessary data is available to all the computation, decision- making, and visualization nodes.

Posted in: Articles, Aerospace
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Taking PC/104 CPU Boards to the Next Performance Level

Since their introduction in 1991, PC/104 standard based systems have been widely adopted in various applications. Unmanned aircraft control, onboard vehicle control and navigation systems, personal communicators, add-on cards for customer specific boards, all utilize PC/104 technology. Many system developers choose this form-factor due to its advantages in terms of low weight, compact size (boards are just 90×96 mm), ease of application development and modification, and mechanical reliability.

Posted in: Articles, Articles, Board-Level Electronics, Electronics & Computers, Design processes, Computer software / hardware, Customization
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Continuous Carbon Nanofibers for Structural Composites

A program of research has addressed key issues in the production of continuous carbon nanofibers and the utilization of carbon nanofibers as the reinforcing components in matrix/fiber composite materials. The goal of this research is to contribute to the development of advanced lightweight structural composites in which the exceptionally high strengths of carbon nanofibers are exploited to obtain mechanical strengths, delamination toughnesses, and fatigue lives greater than would otherwise be possible.

Posted in: Briefs, Materials, Fabrication, Composite materials, Fibers, Lightweight materials, Nanomaterials
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High-Strain-Rate Tests of Epoxy/Aluminum-Powder Composites

Initial tests have been performed in a continuing experimental study to determine selected mechanical properties, at high strain rates, of an epoxy and of composite materials consisting of the epoxy filled with aluminum powders. These composites are examples of the large variety of polymer-matrix/particlefilling composites in general, which are widely used in military and civilian applications. The properties of such composites can be tailored for specific applications through appropriate choices of constituent materials, the proportions of the constituent materials, and the sizes of the particles. Especially in aerospace structural applications, the composites are exposed to complex, temporally varying loads. Therefore, the mechanical properties of such composites’ high strain rates are of increasing importance.

Posted in: Briefs, Materials
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High-Temperature Resins for Composite Materials

Improved, readily processable thermosetting polymer resins are being developed for use as matrix materials in composite-material structures in applications in which there are requirements for thermal stability and hot-wet performance. Heretofore, the development and utilization of polymer resins for such applications have been limited by adverse characteristics that include (1) toxicity of many of the chemicals used to make the resins; (2) poor performance during fires (excessive flame and smoke, dripping, and generation of hazardous substances); (3) significant absorption of water in humid environments, linked to delamination during rapid heating; and (4) in the cases of many of the polymers suitable for use at the highest temperatures, difficulties in the use of newer, less expensive fabrication techniques.

Posted in: Briefs, Materials
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Making Ultra-Hydrophobic Textured Silicone-Rubber Surfaces

Silicone-rubber surfaces microscopically textured in such a manner as to render them ultra-hydrophobic have been fabricated by a method in which breath figures are utilized. Originally, “breath figures” signified fog-like patches formed by condensation of microscopic droplets of water from air exhaled onto cooler surfaces. Now, “breath figures” refers more generally to patches formed by condensation, whether from natural breath or artificial sources. The essence of the method is to use a breath figure to form a pattern of microscopic, approximately hemispherical pits (each pit corresponding to a condensed water droplet) on the surface of a layer of polystyrene, then use the pitted polystyrene surface as a template to cast the silicone rubber having a surface pattern of nanometer- or micron-sized pillars corresponding to the pits.

Posted in: Briefs, Materials
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Time Coding of Asynchronously Transmitted Multi-Source Data

A method of time coding of asynchronously transmitted data from multiple sources has been invented. The method is especially applicable to a data-acquisition and transfer system that operates in a standard asynchronous transfer mode (ATM), in which, at a transmitter, streams of data acquired simultaneously from multiple sources are time-multiplexed, packaged into cells that are sent sequentially over a single wide-band transmission line or other channel to a receiver. The packaging destroys the original temporal relationship among the data streams, but the method enables reconstruction of the data streams in their original temporal relationships at the receiver.

Posted in: Briefs, Electronics & Computers
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Quantum Network Testbed

A document describes the world’s first quantum network testbed — an Internet-compatible fiber-optic data-communication network that is kept extremely secure by use of encryption with quantum key distribution (QKD). The testbed, located in the Boston metropolitan area, includes ten nodes, of which four run continuously over commercial telecommunication fiber-optic links, four utilize free-space optical links, and two are based on propagation of polarization-entangled photon pairs in optical fibers. The document contains an introduction to quantum cryptography, including the basic concepts of, and the rationale for, QKD as implemented in the network. The document goes on to describe the architecture of the network and the design and operation of key systems, subsystems, and components. An important consideration affecting the designs of systems and subsystems is the need to formulate QKD algorithms to foil quantum eavesdropping.

Posted in: Briefs, Electronics & Computers
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