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(Particulate Flow Research Lab) quarterly progress report, July 1, 1991--September 30, 1991

Description: Research at the Particulate Flow Research Lab continued. In the previous report it was mentioned that an anticipated change in the sphere diameter necessitated a resizing of the chute components. A check has indicated that the increased size has added enough weight to require a re-evaluation of the stresses requiring stronger fasteners. Mathematical formalism is given for the chip radiation model, and signal processing of the radiation received from the transmitting chips has been improved. A prototype apparatus has been designed and built in order to collide two identical spheres at a point in space. 4 figs.
Date: October 15, 1991
Creator: Rosato, A.D.; Dave, R.N.; Fischer, I.S. & Carr, W.
Partner: UNT Libraries Government Documents Department

Experiments using non-intrusive particle tracing techniques for granular chute flows. Final report

Description: The objective of this contract was to develop a system capable of non-intrusively tracking the motion of an individual particle for the study of granular flows down inclined chutes. The result of the project is a system capable of following the three-dimensional translational and rotational motion of an individual particle embedded with a flowing granular material. The basic system consists of a sphere embedded with three orthogonal transmitters emitting at different frequencies which induce voltages in an antenna array surrounding the flow regime. Analysis of the induced voltage signals within the framework of a derived model yields both the position and orientation of the sphere. Tests were performed in a small scale model chute as well as in a cylindrical vibrated granular bed, which clearly demonstrates the capability of the system. As a result of discussions at meetings held semi-annually for the Granular Flow Advanced Research Objectives (GFARO) contractors, it was deemed necessary to pursue an additional experimental program as part of this contract related to the measurement of sphere collision properties. The outcome of the work (reported in Appendix C) is the determination of certain properties which are needed for use in computer simulations and theory.
Date: December 31, 1998
Creator: Rosato, A.D.; Dave, R.N. & Fischer, I.S.
Partner: UNT Libraries Government Documents Department

Development of a non-intrusive particle tracing technique for granular chute flows

Description: The development of a non-intrusive particle tracking system to follow the trajectory of an individual particle in three dimensions within a mass of particles is necessary to experimentally validate developing theories of inclined chute granular flows in conjunction with particle dynamics models. An understanding of the exact nature of such flows is of critical importance to a variety of industries concerned with solids handling, as well as in natural geological events. The tracking system, based on the principle of radiosonde'' transmitters coupled to receiving antennae by magnetic induction, is being developed. The radiosonde consists of one or more, orthogonally placed miniature circuits with integral loop antennas, mounted into a sphere of approximately 3/4 in. in diameter. The radiosonde sphere position can be traced during the flow down a chute by analyzing the induced voltage signals in the three or more external orthogonal receiving loop antennas due to the transmitter chips. 22 refs., 15 figs.
Date: January 1, 1992
Creator: Rosato, A.D.; Dave, R.N.; Fischer, I.S. & Carr, W.N.
Partner: UNT Libraries Government Documents Department

Particulate Flow Research Laboratory quarterly progress report, October 1, 1992--December 31, 1992

Description: Only minor changes have been made to the one-transmitter model code since the last report. Most changes were small and improved either code legibility or speed. Several redundant calculations were removed from the inner loop of the program. We performed a series of experiments to determine how well the single-transmitter model matches the actual measured voltages, and how the differences between the predicted and actual behavior of the voltage in the antennas affects the inverse transformation. These experiments used many different linear trajectories and several different sets of calibration points. For most known trajectories we were able to reproduce the path from the measured voltages with an accuracy of no worse than two inches for the worst points. (Most points are substantially more accurate). We have, however, identified two problem regions. The model encounters difficulty when the transmitter crosses the plane of an antenna or when the transmitter is almost parallel to an antenna and is moving nearly parallel to that antenna.When the transmitter crosses an antenna the measured voltage is significantly higher than the model would predict. Currently we're attributing this to small asymmetries and extra wiring in the test transmitter that only becomes significant on a scale of a couple of inches. These will not be present in the actual transmitter. If the new, more symmetric transmitter still has this problem we have worked out an iterative scheme for selectively choosing which antennas to use to calculate the position of the sphere at a given place.
Date: January 1, 1992
Creator: Rosato, A.D.; Dave, R.N. & Fischer, I.S.
Partner: UNT Libraries Government Documents Department

Particulate Flow Research Laboratory quarterly progress report, October 1, 1992--December 31, 1992

Description: Only minor changes have been made to the one-transmitter model code since the last report. Most changes were small and improved either code legibility or speed. Several redundant calculations were removed from the inner loop of the program. We performed a series of experiments to determine how well the single-transmitter model matches the actual measured voltages, and how the differences between the predicted and actual behavior of the voltage in the antennas affects the inverse transformation. These experiments used many different linear trajectories and several different sets of calibration points. For most known trajectories we were able to reproduce the path from the measured voltages with an accuracy of no worse than two inches for the worst points. (Most points are substantially more accurate). We have, however, identified two problem regions. The model encounters difficulty when the transmitter crosses the plane of an antenna or when the transmitter is almost parallel to an antenna and is moving nearly parallel to that antenna.When the transmitter crosses an antenna the measured voltage is significantly higher than the model would predict. Currently we`re attributing this to small asymmetries and extra wiring in the test transmitter that only becomes significant on a scale of a couple of inches. These will not be present in the actual transmitter. If the new, more symmetric transmitter still has this problem we have worked out an iterative scheme for selectively choosing which antennas to use to calculate the position of the sphere at a given place.
Date: December 31, 1992
Creator: Rosato, A. D.; Dave, R. N. & Fischer, I. S.
Partner: UNT Libraries Government Documents Department