SCCUR 2002 at CAL TECH
CRYOGENIC ARGON LOADING OF DIAMOND ANVIL CELLS
High Pressure Science and Engineering Center
The Merrill-Basset Diamond Anvil Cell (DAC) is an extremely effective tool for the observation of pressure effects of crystalline materials by X-ray diffraction measurements. The flat-faced diamond cutlets of the cell commonly have a range of 500-650 µm. Diamond anvils with a diameter of 50 µm or less generate pressures equivalent to those found at the center of the earth. Under similar extreme high pressures we observe unusual changes in the structure of sample crystals. The ability to attain high pressures requires an effective hydrostatic pressure transmitter medium inside the cell. We know solid argon is an excellent medium. We develop a cryogenic method of loading liquid argon into the cell. We then condense and pressurize the argon into a solid state by closing the cell. X-ray diffraction provides a means of testing whether solid argon is actually in the DAC. We then measure the pressure inside the cell using ruby fluorescence.
Author: Ryan L. Palmer
The Purpose of this project was to learn basic control techniques that can be applied to various systems such as anti-aircraft guns, cruise control, automotive suspension, remote control cars and helper robots (robots for disabled persons). The specific plant used for this project was the classical inverted pendulum on a cart. The project involves designing a system that moves the cart back and forth in one dimension causing the pendulum to swing up from a relaxed state and into a balanced upright position. The cart sends back data about the pendulum's angle and the position of the cart. Feedback is used to stabilize the system at the desired equilibrium point. The systems are created on MATLAB Simulink then implemented on a Quanser Consulting Inverted Pendulum setup. Using PID controllers I have been able to cause the system to swing the pendulum up and stabilize its upper equilibrium point while keeping the cart stationary. PID is a basic controller that can help understand the effects of control on system properties such as rise time and steady state error. This research provides me the fundamental knowledge and skills to work on and solve more complex control problems in the future.