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Engineering topics

Carruthers, J. R.

Publications and source records attributed to Carruthers, J. R..

Materials processing in the reduced-gravity environment of space

Studies of the effects of gravitation on the behavior of fluids and the shapes of materials for the years 1977-1982 are reviewed, with a focus on ground-based research which complements and gives direction to experimentation in the reduced-gravity environment of space. Fluid-behavior topics discussed include crystal growth from melts and from vapor, dendritic solidification and casting, multiphase alloy solidification, electrophoresis, convection behavior, and special heat-flow considerations characteristic of the space environment. With regard to solids, such subjects as containerless positioning technology and its applications (in glass preparation, liquid drop and shell studies, nucleation experiments, and measurements of fundamental properties of molten reactants), liquid floating zones, solid self-deformation, and sedimentation and buoyancy effects are considered and illustrated.

Carruthers, J. R.↗

Crystal growth in a low gravity environment

Crystal growth in microgravity possesses several distinct technological advantages over earth-bound processes; containerless handling and reduction of density gradient driven as well as sedimentation flows. Experiments performed in space to date have been basically reproductions of processes currently used on earth and the results have clarified our understanding of crystal growth dynamics. In addition, both unresolved problems and areas requiring further study on earth have been identified. Future work in space processing of materials must address these areas of study as soon as possible if the full potential of a space environment to develop new techniques and materials is to be realized.

Carruthers, J. R.↗

Studies of rotating liquid floating zones on Skylab IV

Liquid zones of water, soap solution and soap foam were deployed between two aligned circular disks which were free to rotate about the zone axis in the microgravity environment of Skylab IV. Such a configuration is of interest in the containerless handling of melts for possible future space processing crystal growth experiments. Three basic types of zone surface deformation and instability were observed for these rotational conditions; axisymmetric shape changes under single disk rotation, nonaxisymmetric, whirling, C-modes for long zones with equal rotation of both disks, and capillary wave phenomena for short zones with equal rotation of both disks. The sources of these instabilities and the conditions promoting them are analyzed in detail from video tape recordings of the Skylab experiments.

Carruthers, J. R.↗

Studies of liquid floating zones on SL-IV, the third Skylab mission

The behavior of liquid floating zones in a zero-gravity environment was studied by Dr. E. Gibson on SL-4. These experiments were designed from the results of previous work on floating zones in a simulated zero-gravity model. Molten floating zones are used on earth for the crystal growth and zone refining of reactive materials. The Skylab studies give some insight into the problems associated with the development of the technique for the future space processing of materials. Preliminary results are presented on the stability of the liquid zone surface under static, rotational and vibrational conditions without gravitational constraints.

Carruthers, J. R.↗