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Automated Solvent Seaming of Large Polyimide Membranes

Success depends on precise control of all relevant process details. A solvent-based welding process enables the joining of precise, cast polyimide membranes at their edges to form larger precise membranes. The process creates a homogeneous, optical - quality seam between abutting membranes, with no overlap and with only a very localized area of figure disturbance. The seam retains 90 percent of the strength of the parent material. The process was developed for original use in the fabrication of wide - aperture membrane optics, with areal densities densities of less than 1 kg/m2, for lightweight telescopes, solar concentrators, antennas, and the like to be deployed in outer space. The process is just as well applicable to the fabrication of large precise polyimide membranes for flat or inflatable solar concentrators and antenna reflectors for terrestrial applications.

Posted in: Briefs

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Manufacturing Precise, Lightweight Paraboloidal Mirrors

Success depends on the proper selection of materials and process conditions. A process for fabricating a precise, diffraction- limited, ultralightweight, composite-material (matrix/fiber) paraboloidal telescope mirror has been devised. Unlike the traditional process of fabrication of heavier glass-based mirrors, this process involves a minimum of manual steps and subjective judgment. Instead, this process involves objectively controllable, repeatable steps; hence, this process is better suited for mass production.

Posted in: Briefs, TSP

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Heat Treatment of Friction-Stir-Welded 7050 Aluminum Plates

Strength, ductility, and resistance to stress corrosion cracking are increased. A method of heat treatment has been developed to reverse some of the deleterious effects of friction stir welding of plates of aluminum alloy 7050. This alloy is considered unweldable by arc and high-energy-density beam fusion welding processes. The alloy can be friction stir welded, but as-welded workpieces exhibit low ductility, low tensile and yield strengths, and low resistance to stress corrosion cracking. Heat treatment according to the present method increases tensile and yield strengths, and minimizes or eliminates stress corrosion cracking. It also increases ductility.

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Discovering New Drugs on the Cellular Level

With the Vision for Space Exploration calling for a sustained human presence in space, astronauts will need to grow plants, while in orbit, for nourishment that they will not receive from only consuming dehydrated foods. As a potential source of food for long-duration missions, space-grown plants could also give astronauts an important psychological boost, as fresh vegetables could serve as a welcomed change from monotonous meals consisting of reconstituted foods in plastic bags. Even more, these plants could likely aid in the recycling of air and wastewater on spacecraft.

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Attaching Thermocouples by Peening or Crimping

These techniques are simple, effective, and minimally invasive. Two simple, effective techniques for attaching thermocouples to metal substrates have been devised for high- temperature applications in which attachment by such conventional means as welding, screws, epoxy, or tape would not be effective. The techniques have been used successfully to attach 0.005-in. (0.127-mm)-diameter type-S thermocouples to substrates of niobium alloy C-103 and stainless steel 416 for measuring temperatures up to 2,600 °F (1,427 °C). The techniques are equally applicable to other thermocouple and substrate materials.

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Lighting the Way for Quicker, Safer Healing

Who's to say that a little light can't go a long way? Tiny light-emitting diode (LED) chips used to grow plants in space are lighting the way for cancer treatment, wound healing, and chronic pain alleviation on Earth.

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Submarine Design Certified on FEA and Sensor Testing

The American Bureau of Shipping certified a submarine solely on the basis of finite element analysis (FEA) and strain sensor testing. Submarine design typically follows American Bureau of Shipping (ABS) code, which establishes properties such as hull thickness, frame stiffness, and porthole and hatch design. During certification, ABS evaluates whether a design follows the relevant codes and then certifies it or not on that basis. The design of a deep-diving submarine was so unique that some ABS rules could not be adhered to.

Posted in: Manufacturing & Prototyping, Briefs

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