Mechanical & Fluid Systems

Device for Automated Cutting and Transfer of Plant Shoots

This device is simple yet effective. A device that enables the automated cutting and transfer of plant shoots is undergoing development for use in the propagation of plants in a nursery or laboratory. At present, it is standard practice for a human technician to use a knife and forceps to cut, separate, and grasp a plant shoot. The great advantage offered by the present device is that its design and operation are simpler than would be those of a device based on the manual cutting/separation/grasping procedure. [The present device should not be confused with a prior device developed for partly the same purpose and described in "Compliant Gripper for a Robotic Manipulator" (NPO-21104), NASA Tech Briefs, Vol. 27, No. 3 (March 2003), page 59.]

Posted in: Briefs, TSP, Mechanical Components

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Extension of Liouville Formalism to Postinstability Dynamics

A fictitious stabilizing force is introduced. A mathematical formalism has been developed for predicting the postinstability motions of a dynamic system governed by a system of nonlinear equations and subject to initial conditions. Previously, there was no general method for prediction and mathematical modeling of postinstability behaviors (e.g., chaos and turbulence) in such a system.

Posted in: Briefs, TSP, Mechanical Components

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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.

Posted in: Briefs, TSP, Mechanical Components

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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.

Posted in: Briefs, Mechanical Components

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Analysis of Designs of Space Laboratories

A report presents a review of the development of laboratories in outer space, starting from the pioneering Skylab and Salyut stations of the United States and the former Soviet Union and progressing through current and anticipated future developments. The report includes textual discussions of space-station designs, illustrated with drawings, photographs, and tables. The approach taken in the review was not to provide a comprehensive catalog of each space laboratory and every design topic that applies to it, but, rather, to illustrate architectural precedents by providing examples that illustrate major design problems and principles to be applied in solving them. Hence, the report deemphasizes information from the most recent space-station literature and concentrates on information from original design reports that show how designs originated and evolved. The most important contribution of the review was the development of a methodology, called "units of analysis," for identifying and analyzing design issues from the perspectives of four broad domains: laboratory science, crew, modes of operations, and the system as a whole.

Posted in: Briefs, TSP, Mechanical Components

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Brush-Wheel Samplers for Planetary Exploration

A report proposes brush-wheel mechanisms for acquiring samples of soils from remote planets. In simplest terms, such a mechanism would contain brush wheels that would be counter-rotated at relatively high speed. The mechanism would be lowered to the ground from a spacecraft or other exploratory vehicle. Upon contact with the ground, the counterrotating brush wheels would kick soil up into a collection chamber. Thus, in form and function, the mechanism would partly resemble traditional street and carpet sweepers. The main advantage of using of brush wheels (in contradistinction to cutting wheels or other, more complex mechanisms) is that upon encountering soil harder than expected, the brushes could simply deflect and the motor(s) could continue to turn. That is, sufficiently flexible brushes would afford resistance to jamming and to overloading of the motors used to rotate the brushes, and so the motors could be made correspondingly lighter and less power hungry. Of course, one could select the brush stiffnesses and motor torques and speeds for greatest effectiveness in sampling soil of a specific anticipated degree of hardness.

Posted in: Briefs, TSP, Mechanical Components

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Lightweight Energy Absorbers for Blast Containers

Aluminum foam liners tested for possible replacement of solid lead liners. Kinetic-energy- absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

Posted in: Briefs, TSP, Mechanical Components

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