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

Automated Data Acquisition for a Prognostics and Diagnostics Health Monitoring System

A highly flexible automated prognostics and diagnostics sensor module (PDSM) prototype is presently under development to be incorporated for data acquisition in a Prognostics and Diagnostics Health Monitoring System (PDHMS). PDHMS acquires, stores, and communicates data gathered from sensors that monitor essential platform components to determine its current diagnostic status. This diagnostic data is used to make reliable prognostications of remaining operational life expectancy based on a platform usage profile.

Posted in: Briefs, Electronics & Computers, Data exchange, Sensors and actuators, Diagnostics, Prognostics

Wettability Tests of Polymer Films and Fabrics

High-strength polymer materials are useful components in many multifunctional materials applications. However, because of low reactivity, their use is inhibited in many processing techniques. Polymer films and fibers possess low surface energies and need to be modified through surface activation prior to being used in composite systems where adhesive bonding is an issue. Treatment of polymer materials through plasma processing is one route to greatly increase surface reactivity. Once the surface has been plasma-modified, wettability by liquids can be examined to determine the treatment effects on the polymer material’s surface reactivity.

Posted in: Briefs, Materials, Joining, Composite materials, Fibers, Materials properties, Polymers

Using a Steering Shaping Function to Improve Human Performance in By-Wire Vehicles

Currently, there is a performance issue regarding vehicle control at higher speeds for some indirect-vision, by-wire military vehicles; that is, those vehicles in which mechanical links between the driver and control devices are replaced by electronic or computerized signals. Work has been performed to assess the current state of knowledge regarding the shaping function. The overall goal was to identify design parameters critical to improving the current by-wire implementation for military tactical vehicles, and to ultimately optimize system (i.e., human-vehicle) performance for the execution of secure mobile operations.

Posted in: Briefs, Mechanical Components, Steer-by-wire, Human machine interface (HMI), Military vehicles and equipment, Vehicle dynamics

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

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

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

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

Virtual Network Computing Software for DataWall Remote Display

VNC (Virtual Network Computing) is open-source software that allows a user to view and interact with a remote computer (known as the VNC server) from a local computer (known as the VNC viewer/client). VNC is used to display multiple remote desktops on the DataWall. The original VNC software can only project the whole desktop from a server to the DataWall. The VNC server and viewer were modified to project the whole desktop or an application of interest from a server to the DataWall.

Posted in: Briefs, Software, Computer software / hardware, Data exchange, Human machine interface (HMI), Displays

Software Suite for a Large Defense System

A suite of software tools was developed to enable networks composed of many hundreds, thousands, or even millions of commodity computers to protect themselves against a variety of security threats. These tools include Anagram, a content-based anomaly detection (AD) tool; ASSURE, which provides automatic software self-healing; and Aeolos, a distributed intrusion detection and event correlation infrastructure.

Posted in: Briefs, Software, Computer software / hardware, Cyber security, Neural networks