Tech Briefs

Single-Phase Rare-Earth Oxide/Aluminum Oxide Glasses

These glasses are suitable for advanced optical applications. Marshall Space Flight Center, Alabama Glasses that comprise rare-earth oxides and aluminum oxide plus, optionally, lesser amounts of other oxides, have been invented. The other oxide(s) can include SiO2, B2O3, GeO2, and/or any of a variety of glass-forming oxides that have been used heretofore in making a variety of common and specialty glasses. The glasses of the invention can be manufactured in bulk single-phase forms to ensure near uniformity in optical and mechanical characteristics, as needed for such devices as optical amplifiers, lasers, and optical waveguides (including optical fibers). These glasses can also be formulated to have high indices of refraction, as needed in some of such devices.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Solving Complex Engineering Challenges of Large Composite Aerostructures

Large-scale composite parts present unique design and manufacturing challenges in aerospace. Composites are becoming the material of choice for the manufacture of large, complex aerostructures. The aft section of the jumbo Airbus A380 and the wings of the military transport Airbus A400, for example, are all made of carbon-fiber composites. Boeing, for the first time, is building an all-composite airframe and wings for its groundbreaking 787 airliner. Because of these and other recent manufacturing achievements, there is little doubt that composite materials will be used extensively in many future aircraft programs — from wide-body jets and commercial airliners to regional, business, and “very light” airplanes.

Posted in: Manufacturing & Prototyping, Briefs

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Regulating Glucose and pH, and Monitoring Oxygen in a Bioreactor

Glucose and oxygen concentrations are monitored, and glucose concentration and pH are adjusted as needed. Figure 1 is a simplified schematic diagram of a system that automatically regulates the concentration of glucose or pH in a liquid culture medium that is circulated through a rotating-wall perfused bioreactor. Another system, shown in Figure 2, monitors the concentration of oxygen in the culture medium.

Posted in: Medical, Briefs

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Implantable Wireless MEMS Sensors for Medical Uses

Sensors designed and fabricated according to the principles of microelectromechanical systems (MEMS) are being developed for several medical applications in outer space and on Earth.The designs of these sensors are based on a core design family of pressure sensors, small enough to fit into the eye of a needle, that are fabricated by a “dissolved wafer” process. The sensors are expected to be implantable, battery-less, and wireless. They would be both powered and interrogated by hand-held radio transceivers from distances up to about 6 in. (about 15 cm). One type of sensor would be used to measure blood pressure, particularly for congestive heart failure. Another type would be used to monitor fluids in patients who have hydrocephalus (high brain pressure). Still other types would be used to detect errors in delivery of drugs and to help patients having congestive heart failure.

Posted in: Medical, Briefs

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Dehydrating and Sterilizing Wastes Using Supercritical CO2

A relatively low-temperature process for dehydrating and sterilizing biohazardous wastes in an enclosed life-support system exploits (1) the superior mass-transport properties of supercritical fluids in general and (2) the demonstrated sterilizing property of supercritical CO2 in particular. The wastes to be treated are placed in a chamber. Liquid CO2, drawn from storage at a pressure of 850 psi (˜5.9 MPa) and temperature of 0 °C, is compressed to pressure of 2 kpsi (˜14 MPa) and made to flow into the chamber. The compression raises the temperature to 10 °C. The chamber and its contents are then further heated to 40 °C, putting the CO2 into a supercritical state, in which it kills microorganisms in the chamber. Carrying dissolved water, the CO2 leaves the chamber through a back-pressure regulator, through which it is expanded back to the storage pressure. The expanded CO2 is refrigerated to extract the dissolved water as ice, and is then returned to the storage tank at 0 °C.

Posted in: Bio-Medical, Medical, Briefs

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Multiaxis, Lightweight, Computer-Controlled Exercise System

This system offers unprecedented versatility for physical conditioning and evaluation The multipurpose, multiaxial, isokinetic dynamometer (MMID) is a computer-controlled system of exercise machinery that can serve as a means for quantitatively assessing a subject’s muscle coordination, range of motion, strength, and overall physical condition with respect to a wide variety of forces, motions, and exercise regimens. The MMID is easily reconfigurable and compactly stowable and, in comparison with prior computer-controlled exercise systems, it weighs less, costs less, and offers more capabilities.

Posted in: Medical, Briefs

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Simplified Optics and Controls for Laser Communications

NASA’s Jet Propulsion Laboratory, Pasadena, California A document discusses an architecture of a spaceborne laser communication system that provides for a simplified control subsystem that stabilizes the line of sight in a desired direction. Heretofore, a typical design for a spaceborne laser communication system has called for a high-bandwidth control loop, a steering mirror and associated optics, and a fast steering mirror actuator to stabilize the line of sight in the presence of vibrations. In the present architecture, the need for this fast steering-mirror subsystem is eliminated by mounting the laser-communication optics on a disturbance-free platform (DFP) that suppresses coupling of vibrations to the optics by ≥60 dB. Taking advantage of microgravitation, in the DFP, the optical assembly is free-flying relative to the rest of the spacecraft, and a low-spring-constant pointing control subsystem exerts small forces to regulate the position and orientation of the optics via voice coils. All steering is effected via the DFP, which can be controlled in all six degrees of freedom relative to the spacecraft. A second control loop, closed around a position sensor and the spacecraft attitude-control system, moves the spacecraft as needed to prevent mechanical contact with the optical assembly.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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