Tech Briefs

Coupled-Layer Architecture for Advanced Software for Robots

Decision-making and functional infrastructures interact at all levels of granularity. The title "Coupled Layer Architecture for Robotics Autonomy" (CLARATy) refers to a software architecture for robots that has been proposed to (1) improve the modularity of robotic-system software while (2) tightening the coupling between autonomy and control software subsystems. Whereas prior robotic architectures have typically been characterized by three layers, the CLARATy is characterized by only two layers. The CLARATy provides for interaction of decision-making and functional infrastructures at all levels of system granularity. This architecture is flexible enough to encompass research and application domains, and provides for an explicit coupling of artificial-intelligence and robotics techniques. The architecture is also implemented in an object-oriented fashion that makes it possible to leverage software design through both inheritance and aggregation, thereby eliminating the need for duplication of effort in the development of new software.

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Characteristics of Dynamics of Intelligent Systems

These characteristics are proposed as means of discriminating between living and nonliving systems. An investigation of nonlinear mathematical models of dynamics has led to the selection of characteristics that could be useful for distinguishing mathematically between the behaviors of (1) intelligent or living systems and (2) nonliving systems. As contemplated here, an intelligent or living system could range from a natural or artificial single-cell organism at one extreme to the whole of human society at the other extreme, whereas a nonliving system could be, for example, a collection of interacting particles or mechanisms. Among other findings, the investigation has revealed that living systems can be characterized by nonlinear evolution of probability distributions over different possible choices of the next steps in their motions.

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Analyzing Aeroelasticity in Turbomachines

ASTROP2-LE is a computer program that predicts flutter and forced responses of blades, vanes, and other components of such turbomachines as fans, compressors, and turbines. ASTROP2-LE is based on the ASTROP2 program, developed previously for analysis of stability of turbomachinery components. In developing ASTROP2-LE, ASTROP2 was modified to include a capability for modeling forced responses. The program was also modified to add a capability for analysis of aeroelasticity with mistuning and unsteady aerodynamic solutions from another program, LINFLX2D, that solves the linearized Euler equations of unsteady two-dimensional flow. Using LINFLX2D to calculate unsteady aerodynamic loads, it is possible to analyze effects of transonic flow on flutter and forced response. ASTROP2-LE can be used to analyze subsonic, transonic, and supersonic aerodynamics and structural mistuning for rotors with blades of differing structural properties. It calculates the aerodynamic damping of a blade system operating in airflow so that stability can be assessed. The code also predicts the magnitudes and frequencies of the unsteady aerodynamic forces on the airfoils of a blade row from incoming wakes. This information can be used in high-cycle-fatigue analysis to predict the fatigue lives of the blades.

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Manufacturing Process Management for Test

Test is critical to the board manufacturing process. Effective test ensures quality and customer satisfaction both for the OEM (original equipment manufacturer) and the CEM (contract electronics manufacturer). By isolating defects before product shipment, test minimizes returns and related costs. But test takes time, and the cost can be prohibitive.

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Improved Process for Fabricating Carbon Nanotube Probes

An improved process has been developed for the efficient fabrication of carbon nanotube probes for use in atomic-force microscopes (AFMs) and nanomanipulators. Relative to prior nanotube tip production processes, this process offers advantages in alignment of the nanotube on the cantilever and stability of the nanotube's attachment. A procedure has also been developed at Ames that effectively sharpens the multiwalled nanotube, which improves the resolution of the multiwalled nanotube probes and, combined with the greater stability of multiwalled nanotube probes, increases the effective resolution of these probes, making them comparable in resolution to single-walled carbon nanotube probes. The robust attachment derived from this improved fabrication method and the natural strength and resiliency of the nanotube itself produces an AFM probe with an extremely long imaging lifetime. In a longevity test, a nanotube tip imaged a silicon nitride surface for 15 hours without measurable loss of resolution. In contrast, the resolution of conventional silicon probes noticeably begins to degrade within minutes. These carbon nanotube probes have many possible applications in the semiconductor industry, particularly as devices are approaching the nanometer scale and new atomic layer deposition techniques necessitate a higher resolution characterization technique. Previously at Ames, the use of nanotube probes has been demonstrated for imaging photoresist patterns with high aspect ratio. In addition, these tips have been used to analyze Mars simulant dust grains, extremophile protein crystals, and DNA structure. This NASA technology is being commercialized through Convergent Science and Technology Inc. ().

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Explosion Welding for Hermetic Containerization

There is no need to decontaminate the outside of the container. Figure 1. The Explosion Seals the Samples in the container while simultaneously excluding previous exterior container contamination from the clean environment.Figure 2. Sacrificial Metal is squeezed out, the container walls are cut, and the container walls are welded together on both sides of the cut.A container designed for storing samples of hazardous material features a double wall, part of which is sacrificed during an explosion-welding process in which the container is sealed and transferred to a clean environment. The major advantage of this container sealing process is that once the samples have been sealed inside, the outer wall of what remains of the container is a clean surface that has not come into contact with the environment from which the samples were taken. Thus, there is no need to devise a decontamination process capable of mitigating all hazards that might be posed by unanticipated radioactive, chemical, and/or biological contamination of the outside of the container. The container sealing method was originally intended to be used to return samples from Mars to Earth, but it could also be used to store samples of hazardous materials, without the need to decontaminate its outer surface.

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Dry Process for Making Polyimide/Carbon-and-Boron-Fiber Tape

The tape has superior properties and can be used in automated tape placement. A dry process has been invented as an improved means of manufacturing composite prepreg tapes that consist of high- temperature thermoplastic polyimide resin matrices reinforced with carbon and boron fibers. Such tapes are used (especially in the aircraft industry) to fabricate strong, lightweight composite- material structural components. The inclusion of boron fibers results in compression strengths greater than can be achieved by use of carbon fibers alone.

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