Tech Briefs

Advances Toward Development of "Smart Dust" Biosensors

Progress has been made toward meeting several technical challenges in a continuing effort to develop “smart dust” sensors for remote detection of chemical and biological agents. Until now, the state of the art of laboratory-on-a-chip devices has been typified by microfluidic cartridges variously mounted in or connected to desktop or handheld devices. Smart dust sensors would be smaller: they would be submillimeter-sized devices, the implementation of which would necessitate levels of miniaturization and integration heretofore known only in biological systems.

Posted in: Briefs, Physical Sciences, Downsizing, Remote sensing, Chemicals, Biohazards

Structural Composite Batteries

A continuing program of research and development is devoted to the design, fabrication, and testing of polymeric composite- material devices that are multifunctional in the sense that they both store electrochemical energy and bear mechanical loads. It is anticipated that if designed to exhibit sufficient structural and energy efficiencies, these devices could enable significant reductions in the weights of systems in which they could be used, by supplanting electrically inert structural components and conventional batteries while providing supplementary power for lightload applications.

Posted in: Briefs, Physical Sciences, Aircraft structures, Body structures, Batteries, Energy storage systems, Composite materials, Polymers

Mechanical Aspects of Structural Composite Batteries

In furtherance of the development described in the immediately preceding article, an experimental study focusing on mechanical aspects of structural composite batteries was performed. In this study, battery component materials, battery components, and fully assembled structural composite batteries were subjected to tensile tests. Limited electrochemical tests were also performed.

Posted in: Briefs, Physical Sciences, Aircraft structures, Body structures, Batteries, Energy storage systems, Composite materials, Test procedures

Sensor Validation Using Nonlinear Minor-Component Analysis

Aconcept of sensor validation using nonlinear minor-component analysis (NLMCA) has been proposed as a theoretical basis of a sensor fault-detection-and isolation (FDI) module in a fault-tolerant control system of an aircraft jet engine or other complex physical plant. As used here, "sensor validation" signifies, loosely, analysis of the readouts of all the sensors in such a system for the purpose of identifying which (if any) sensors are faulty and, if possible, the magnitudes of the faults. Once a fault in a sensor or any other component was detected and isolated, the fault-tolerant control system would automatically reconfigure itself to compensate for the effect of that and any other faults so as to maintain acceptable (or as nearly acceptable as possible) control performance of the plant even in the presence of the faults. In the case of a faulty sensor, the system would utilize any available analytical redundancy among all sensor signals to estimate the value of the physical quantity desired to be measured by that sensor, and that value would then be used for feedback control.

Posted in: Briefs, Information Technology, Finite element analysis, On-board diagnostics, Sensors and actuators

Enlightened Multiscale Simulation of Biochemical Networks

A continuing research project is dedicated to development of mathematical and software infrastructure in support of post genomics research in systems biology. One near-term objective of the project is to contribute to deeper understanding of the organizational principles of biological networks. A distinguishing theme of this project is a focus on scalable methods of robustness and theoretically sound methods of the use of experimental data to validate (or invalidate) models; this theme stands in contrast to the heretofore prevalent theme of relying purely on simulation.

Posted in: Briefs, Information Technology, Mathematical models, Computer software / hardware, Biological sciences, Product development, Research and development

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

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