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Better VPS Fabrication of Crucibles and Furnace Cartridges

The choice of alloy composition and processing parameters is important. An experimental investigation has shown that by (1) vacuum plasma spraying (VPS) of suitable refractory metal alloys on graphite mandrels, and then (2) heat-treating the VPS alloy deposits under suitable conditions, it is possible to fabricate improved crucibles and furnace cartridges that could be used at maximum temperatures between 1,400 and 1,600 °C and that could withstand chemical attack by the materials to be heated in the crucibles and cartridges. Taken by itself, the basic concept of fabricating furnace cartridges by VPS of refractory materials onto graphite mandrels is not new; taken by itself, the basic concept of heat treatment of VPS deposits for use as other than furnace cartridges is also not new; however, prior to this investigation, experimental crucibles and furnace cartridges fabricated by VPS had not been heat treated and had been found to be relatively weak and brittle. Accordingly, the investigation was directed toward determining whether certain combinations of (1) refractory alloy compositions, (2) VPS parameters, and (3) heat-treatment parameters could result in VPS-fabricated components with increased ductility.

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Antistatic Polycarbonate/Copper Oxide Composite

Surface resistance lies in the desired range. A composite material consisting of polycarbonate filled with copper oxide has been found to be suitable as an antistatic material. This material was developed to satisfy a requirement for an antistatic material that has a mass density less than that of aluminum and that exhibits an acceptably low level of outgassing in a vacuum.

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Stable, Thermally Conductive Fillers for Bolted Joints

A commercial structural epoxy [Super Koropon (or equivalent)] has been found to be a suitable filler material for bolted joints that are required to have large thermal conductances. The contact area of such a joint can be less than 1 percent of the apparent joint area, the exact value depending on the roughnesses of the mating surfaces. By occupying the valleys between contact peaks, the filler widens the effective cross section for thermal conduction. In comparison with prior thermal joint-filler materials, the present epoxy offers advantages of stability, ease of application, and —as a byproduct of its stability — lasting protection against corrosion. Moreover, unlike silicone greases that have been used previously, this epoxy does not migrate to contaminate adjacent surfaces. Because this epoxy in its uncured state wets metal joint surfaces and has low viscosity, it readily flows to fill the gaps between the mating surfaces: these characteristics affect the overall thermal conductance of the joint more than does the bulk thermal conductivity of the epoxy, which is not exceptional. The thermal conductances of metal-to-metal joints containing this epoxy were found to range between 5 and 8 times those of unfilled joints.

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Self-Deployable Spring-Strip Booms

These structures can be stowed compactly with small forces and become rigid once deployed. Booms and other structures consisting mainly of thin spring strips are undergoing development. These structures are designed to be lightweight, to be compactly stowable, and to be capable of springing to stable configurations at full extension once released from stowage. Conceived for use as self-deploying structures in outer space, portable structures of this type may also be useful on Earth in applications in which there are requirements for light weight and small transportation volume.

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Automated Serial Sectioning for 3D Reconstruction

Automation increases speed and reduces uncertainty in alignment. Figure 1 depicts some aspects of an apparatus and method for automated serial sectioning of a specimen of a solder, aluminum, or other relatively soft opaque material. The apparatus includes a small milling machine (micromiller) that takes precise, shallow cuts (increments of depth as small as 1 μm) to expose successive sections. A microscope equipped with an electronic camera, mounted in a fixed position on the micromiller, takes pictures of the newly exposed specimen surface at each increment of depth. The images are digitized, and the resulting data are subsequently processed to reconstruct three-dimensional (3D) features of the specimen.

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Variable Frequency Drives For More Efficient Manufacturing Operations

VFDs provide adjustable motor speed that reduces energy consumption of fans. Energy savings is one of the key ingredients in reducing costs for any manufacturing operation. A simple, but very effective, way to save energy is by making fans run more efficiently. Almost every manufacturing application uses fans, and variable frequency drives (VFDs) provide the adjustable motor speed that can actually reduce energy consumption in fans. This concept is demonstrated in the following example where VFDs are used in tandem with industrial robots for paint spray booth applications.

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Time Analyzer For Time Synchronization and Monitor of the Deep Space Network

A software package has been developed to measure, monitor, and archive the performance of timing signals distributed in the NASA Deep Space Network. Timing signals are generated from a central master clock and distributed to over 100 users at distances up to 30 kilometers. The time offset due to internal distribution delays and time jitter with respect to the central master clock are critical for successful spacecraft navigation, radio science, and very long baseline interferometry (VLBI) applications. The instrument controller and operator interface software is written in LabView and runs on the Linux operating system. The software controls a commercial multiplexer to switch 120 separate timing signals to measure offset and jitter with a time-interval counter referenced to the master clock. The offset of each channel is displayed in histogram form, and “out of specification” alarms are sent to a central complex monitor and control system. At any time, the measurement cycle of 120 signals can be interrupted for diagnostic tests on an individual channel. The instrument also routinely monitors and archives the longterm stability of all frequency standards or any other 1-pps source compared against the master clock. All data is stored and made available for remote access via network connection.

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