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Graphite Composite Booms With Integral Hinges

A document discusses lightweight instrument booms under development for use aboard spacecraft. A boom of this type comprises a thin-walled graphite-fiber/matrix composite tube with an integral hinge that can be bent for stowage and later allowed to spring back to straighten the boom for deployment in outer space. The boom design takes advantage of both the stiffness of the composite in tubular geometry and the flexibility of thin sections of the composite. The hinge is formed by machining windows in the tube at diametrically opposite locations so that there remain two opposing cylindrical strips resembling measuring tapes. Essential to the design is a proprietary composite layup that renders the hinge tough yet flexible enough to be bendable as much as 90° in either of two opposite directions. When the boom is released for deployment, the torque exerted by the bent hinge suffices to overcome parasitic resistance from harnesses and other equipment, so that the two sections of the hinge snap to a straight, rigid condition in the same manner as that of measuring tapes. Issues addressed in development thus far include selection of materials, out-of-plane bending, edge cracking, and separation of plies.

Posted in: Briefs, TSP

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Alignment Cube With One Diffractive Face

Only one theodolite is needed instead of two. An enhanced alignment cube has been invented for use in a confined setting (e.g., a cryogenic chamber) in which optical access may be limited to a single line of sight. Whereas traditional alignment-cube practice entails the use of two theodolites aimed along two lines of sight, the enhanced alignment cube yields complete alignment information through use of a single theodolite aimed along a single line of sight.

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Surface Acoustic Wave Sensor for Viscosity Measurement

Acoustic wave solid-state viscometers can be integrated into in-line, real-time monitoring and process control systems. Viscosity is a measure of the resistance of a liquid to flow, and is an important measurement requirement in industrial process control and OEM applications. Viscosity describes the retarding force that is proportional to the rate of deformation. This so-called shear rate has units of s-1 and describes the crossstream gradient of the flow speed.

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Automated Low-Gravitation Facility Would Make Optical Fibers

A report describes a proposed automated facility that would be operated in outer space to produce high-quality optical fibers from fluoride-based glasses, free of light-scattering crystallites that form during production in normal Earth gravitation. Before launch, glass preforms would be loaded into a mechanism that would later dispense them. A dispensed preform would be melted, cooled to its glass-transition temperature rapidly enough to prevent crystallization, cooled to ambient temperature, then pushed into a preform tip heater, wherein it would be reheated to the softening temperature. A robotic manipulator would touch a fused-silica rod to the softened glass to initiate pulling of a fiber. The robot would pull the fiber to an attachment on a take-up spool, which would thereafter be turned to pull the fiber. The diameter of the fiber would depend on the pulling speed and the viscosity of the glass at the preform tip. Upon depletion of a preform, the robot would place the filled spool in storage and position an empty spool to pull a fiber from a new preform. Pulling would be remotely monitored by a video camera and restarted by remote command if a break in the fiber were observed.

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Pulse-Flow Microencapsulation System

Microcapsules are produced continuously under controlled, sterile conditions. The pulse-flow microencapsulation system (PFMS) is an automated system that continuously produces a stream of liquid-filled microcapsules for delivery of therapeutic agents to target tissues. Prior microencapsulation systems have relied on batch processes that involve transfer of batches between different apparatuses for different stages of production followed by sampling for acquisition of quality-control data, including measurements of size. In contrast, the PFMS is a single, microprocessor- controlled system that performs all processing steps, including acquisition of quality-control data. The quality-control data can be used as real-time feedback to ensure the production of large quantities of uniform microcapsules.

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Nuclear Reactor Cooling Valve Design Optimized With FEA

Finite element analysis simulated the valve’s condition following an earthquake. Atomic Energy of Canada, Ltd., a subcontractor of Societatea Nationala Nucleoelectrica S.A. (SNN) of Romania, contracted Badger Meter to model, test, and produce a set of precision valves for Cernavoda Unit 2, the second nuclear power plant in Cernavoda, Romania. The main concern for the construction and operation of the valves was their survivability and continued functioning after enduring an earthquake. In nuclear power plants, such valves control the cooling of the nuclear reactors where continued flow of water around the nuclear core is essential for safety. After the earthquake that precipitated the eruption of Mt. Saint Helens in 1980, testing criteria for valves routinely has included their capability to ensure the safe functioning of the reactor after seismic events, at least in terms of cooling capacity.

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Wholly Aromatic Ether-Imides as n-Type Semiconductors

Some of the compounds exhibit promising electron-transport properties. Some wholly aromatic ether-imides consisting of rod-shaped, relatively-low-mass molecules that can form liquid crystals have been investigated for potential utility as electron-donor-type (n-type) organic semiconductors. It is envisioned that after further research to improve understanding of their physical and chemical properties, compounds of this type would be used to make thin-film semiconductor devices (e.g., photovoltaic cells and field-effect transistors) on flexible electronic-circuit substrates.

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