Home

Cluster-Assembled Soft Magnets for Power Electronics Applications

This technique uses nanocluster assembly to produce model soft magnetic materials with simpler chemical composition than existing materials and well-controlled nanostructure, and to use these materials to improve understanding of the fundamental mechanisms responsible for the soft magnetic properties. An inert-gas condensation deposition chamber was developed, and transition-metal, rare-earth, and alloy nanoparticles with mean grain size D from 5 - 50 rim were deposited.

Posted in: Briefs, Materials
Read More >>

Fluidic Flexible Matrix Composites for Autonomous Structural Tailoring

In previous research, a high-mechanical- advantage actuator system inspired by the fibrillar networks in plant cell walls was developed. One of the basic elements in the actuator system is a composite tube consisting of a flexible matrix and multiple layers of oriented, high-performance fibers such as carbon. By tailoring the properties of the fibers and matrix of the flexible matrix composite (FMC) tube, one can create a material that is flexible in certain directions, yet compliant in others. For example, the ratio of Young's moduli in the directions parallel and transverse to the fibers can range from 102 to 104. Strands of such FMC material can be wound into a tube at selected angles relative to the winding axis (a process called filament winding) such that the tube can contract or elongate axially via internal pressurization. It was previously shown that large strain and large force can be achieved with individual, pressurized FMC tubes, and that parallel arrays of tubular elements can be integrated to form 2D adaptive structures (e.g., skins and plates with multiple tubes).

Posted in: Briefs, Materials
Read More >>

Infrastructure for Development of Secure, Reliable Software

The Verification and Automated Reasoning research group at Cornell University has been building an infrastructure, comprising human expertise and computational resources, for the development of secure, reliable software for critical military applications. Such software includes distributed real-time embedded software systems, which are inherently complex and difficult to understand and specify. The infrastructure includes both efficient means of constructing the software and mathematically rigorous means of ensuring that the software will be secure and correct by construction.

Posted in: Briefs, Information Technology
Read More >>

A Formal Model of the Attack Surface of a Software System

A formal model has been devised to impart some mathematical rigor to the concept of the attack surface of a software system. Complementing the model is a definition of a quantitative measure of the attack surface as an indicator of the relative insecurity of the system (the larger the attack surface, the more insecure the system). The model and the quantitative measure are intended to serve as systematic means of assessing progress in the development of secure software; they are expected to be especially valuable for evaluating the relative degree of security of two successive versions of nominally the same computer program.

Posted in: Briefs, Information Technology
Read More >>

AC Coupled Interconnect for Low-Power Spaceborne Electronics

An AC coupled interconnect (ACCI) has been developed that could be used to create multiple solutions to contactless chip-to-chip communications. Assembly and testing of a 0.18 um bulk CMOS chip containing multiple circuit experiments were performed. Figure 1 shows the chip floorplan, chip layout for the wire bonded experiments, and a microscope photograph of the die. The experiments tested in this phase of measurements were located around the periphery of the die in the band designated in the die photo of Figure 1.

Posted in: Briefs, Electronics & Computers, Architecture, Integrated circuits, Wireless communication systems, Spacecraft
Read More >>

Fuzzy System for Fault Diagnostics in Power Electronics-Based Brake-by-Wire System

Research in fuzzy diagnostics of brake-by-wire systems focuses on the power electronics switches, since they are often considered to be the weakest link in the system. The objective of fault diagnostics in the power electronics of the brake-by-wire system is to accurately locate any faults within the circuit as soon as they occur.

Posted in: Briefs, Electronics & Computers
Read More >>

High-Voltage, High-Temperature Power Electronics Capacitor

A novel high- temperature, high- voltage power electronics capacitor incorporates materials of construction and electrical components that have been initially designed as a segment of an integral electronics component, package, or system to be subjected to harsh or high- temperature environments. The capacitor can withstand operating temperatures in excess of 300°C, while maintaining a capacitance between a fraction of 1 to several μFs.

Posted in: Briefs, Electronics & Computers
Read More >>

Evaluation of Performance of WL Fe-Based Spin-LEDs

A study was performed to evaluate the performance of a recently developed type of Fe-based spin-light-emitting diodes (spin-LEDs) that incorporate wetting layers (WLs). [The term "wetting layer" has two slightly different meanings as explained below.] Light beams emitted by the WL Febased spin-LEDs were found to exhibit the same high degree of circular polarization as do those of previously developed Fe-based spin-LEDs, but differ in one very important aspect: they are an order of magnitude brighter than those emitted by their previously developed counterparts. As a consequence, the WL Fe-based spin-LEDs function reliably at room temperature, whereas their previously developed counterparts do not.

Posted in: Briefs, Photonics
Read More >>

Advances Toward Affordable High-Energy Laser Modules

A multidisciplinary research project entitled “Affordable High-Energy Lasers” has made numerous contributions to the development of several types of advanced laser modules, including not only lasers but also coupling optics and integral laser/ coupling-optic combinations. There are numerous potential applications for such modules, including weaponry, lidar, high-data-rate optical communications, interferometry, spectroscopy, remote sensing, and processing of materials. The devices developed in this project include novel fiber lasers, novel vertical-external-cavity surface emitting lasers (VECSELs), and a radially emitting photonic-bandgap (PBG) polymer fiber laser. Somewhat more specifically, the contributions are summarized as follows:

Posted in: Briefs, Photonics, Design processes, Lasers, Product development, Research and development
Read More >>

Lasing Consequences of Silicon Nanostructures

While silicon electronics has been a success in modem technologies, silicon photonics is still in development and in need of a laser source. Many approaches have been explored, from anodized silicon luminescence, to generating direct emissions by quantum-confinement, and to indirect down-conversion of a shorter wavelength laser light via silicon's nonlinear dielectric responses. One approach that was developed has led to the demonstration of laser emission in silicon-on-insulator at cryogenic temperatures (<85K).

Posted in: Briefs, Photonics
Read More >>