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Algorithm Optimally Allocates Actuation of a Spacecraft

A report presents an algorithm that solves the following problem: Allocate the force and/or torque to be exerted by each thruster and reaction-wheel assembly on a spacecraft for best performance, defined as minimizing the error between (1) the total force and torque commanded by the spacecraft control system and (2) the total of forces and torques actually exerted by all the thrusters and reaction wheels. The algorithm incorporates the matrix⋅vector relationship between (1) the total applied force and torque and (2) the individual actuator force and torque values. It takes account of such constraints as lower and upper limits on the force or torque that can be applied by a given actuator. The algorithm divides the aforementioned problem into two optimization problems that it solves sequentially. These problems are of a type, known in the art as semi-definite programming problems, that involve linear matrix inequalities. The algorithm incorporates, as subalgorithms, prior algorithms that solve such optimization problems very efficiently. The algorithm affords the additional advantage that the solution requires the minimum rate of consumption of fuel for the given best performance.

Posted in: Briefs, Mechanical Components

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Maintain Food Crispiness from Freezer Storage to Microwave Preparation

Methods are sought to replicate the texture of crunchy food in a convenience food stored in a freezer and prepared in a microwave oven. All ingredient-based solutions must be GRAS (generally recognized as safe) for human consumption. Cost must be within 1 to 2 cents per pound for the final product, and cooking time, once out of the box, must be complete in 4 to 6 minutes. Storage time for the packaged food should be 18 months in a home freezer.

Posted in: NASA Tech Needs

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Reusable, Dry Adhesive Material Utilizing Vertically Aligned Multiwalled Carbon Nanotube Array

A novel dry adhesive is being developed that can mimic the hairs on a gecko's foot using vertically aligned multiwalled carbon nanotube (CNT) array. The use of CNT array as dry adhesive material allows reproducing biological adhesion structures and generates fairly strong adhesion strength (over 100 N per centimeter square). CNTs are known to have extraordinary mechanical, thermal and electrical properties. This adhesive can be bent repeatedly with large deflection without failure, which intrinsically results in a reusable or re-attachable dry adhesive. The highly hydrophobic property of CNTs makes them free from the clumping problem, which the polymer based synthetic hair structures face. This product's adhesion is so effective it can be directly applied to glass.

Posted in: Techs for License

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Reusable Adhesive Thermal Interface Material (TIM) To Improve the Contact Thermal Conductance

Current TIM technologies include thermal greases or pastes, phase change materials, solders and thermally conductive adhesive tapes. The thermal conductivity of the best thermal greases available in the market are on the order of 10^5 W/m^2 -K. However, thermal greases, which are single use applications, are oily so their utilization is messy, making them difficult to apply in a thin, uniform coat. This reusable technology employs vertically aligned carbon nanotubes (CNTs) to bridge the interfaces. By using a CNT array as dry interface material, his technology can perform as a thermally conductive tape that provides not only good thermal conducting ability but also strong mechanical bonding between the mating surfaces. It has been shown that a small fraction of CNTs as filling material could induce a 125% enhancement in thermal transport. This interface material can be directly applied to any interface that needs high thermal conductivity.

Posted in: Techs for License

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Opportunity to Collaborate in a New CNT Array Adhesion Tape

A US government funded company is seeking industry support for further testing and development of its carbon nanotube (CNT) adhesive. The time frame for testing is the 3th quarter of 2007.

Posted in: Techs for License

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Multi-Purpose Split-Duct System for Cables

The cable industry uses cylindrical one-piece ducting, but installing cables in such a duct is labor-intensive, difficult, time-consuming, and expensive. This split-duct system features a patented extrusion manufactured from highimpact ABS plastic. The duct sections are hinged together along a longitudinal edge with an integral hinge and “snap” closing system. The system is placed in a trench in a “double-U” configuration and the cables are then laid into the duct. Once the cables are laid, the other half of the ducting system snaps into place, locking the two halves firmly together. The ducting system can also be placed above ground or in ceilings, and comes in a standard length of 3 meters, including bends, tees, and offset sections. Get the complete report on this technology at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: Techs for License

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Method of Making Textile Articles Impregnated with Predetermined Levels of Antibacterial Activity

This invention is a method for impregnating textiles with a predetermined amount of durable antibacterial materials (inorganic compound). BacterProof™ is a patented method for embedding an inorganic compound that kills both grampositive and gram-negative bacteria. The inorganic compound is embedded into synthetic fibers like polyester and nylon, which is then blended with cotton in a procedure that produces a fabric with superb antibacterial properties. Any bacteria that comes into contact with the BacterProof™ will be killed before it has a chance to multiply and infect the patient or be transferred to another patient by medical staff. In addition to being self-disinfecting, the fabric is nontoxic, allergy-free, odorless, and contains no chemicals. Get the complete report on this technology at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: Techs for License

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