December 1999 |
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DIAL's Research Highlights | |
Diagnostic Instrumentation & Analysis Laboratory
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Subtask 1.2 |
Detection of chlorinated organics by cavity ring-down spectroscopy. Work is continuing on acquiring spectra of chlorinated aromatics. New software is being written for analysis of data acquired with new hardware. |
Subtask 1.3 |
Volatile organic compound monitoring using diode lasers. By the close of December 1999, successful measurements of the volatile organic compounds (VOCs) benzene and chlorobenzene had been carried out in air and nitrogen using diode laser absorption spectroscopy. To our knowledge, these were the first atmospheric pressure measurements for VOCs to be carried out using diode lasers. Detection limits in the tens of part-per-million range were achieved in these initial experiments, indicating that a more advanced technique such as diode laser cavity ringdown spectroscopy should readily achieve low part-per-billion level detection in atmospheric pressure air. |
Subtask 1.4 |
LIF of long-lived radionuclides. During December, we installed shorter legs on our optical table. This permits us to direct the laser beam directly into the ICP plasma without having to use mirrors to adjust the beam height. This is important since laser power is lost at each surface because optical surfaces are not perfectly transmissive/reflective; this is especially important in the ultraviolet where most of the metallic transitions are since laser power is lower in this wavelength region; thus not needing optics enables us to deliver more photons to the ICP plasma and thus achieve lower limits of LIF detection. The new ICP system was tested and found to be working properly. |
Subtask 1.7 |
Guided wave nondestructive evaluation technique development and demonstration. On the buffer rod methodology development for the viscosity measurement on hot fluids (glass melting process), new materials were considered for the fabrication of the relatively long buffer rod (2 ft). Also, modifications on the graphite rods are being considered. Several materials related issues still remain due to the increase in the length of the buffer rod. On the guided wave technique for tank wall NDE, further work on modeling was conducted. Some initial results are encouraging. |
Subtask 3.1 |
Validation and application of the environmental simulation program. Determination of the solid-liquid equilibrium points for natrophosphate (Na7F(PO4)2 19H2O were initiated. These experiments follow the previous theoretical comparisons between ESP and SOLGASMIX that indicated some discrepancies between the two calculations. The experiments are being conducted at three temperatures (25, 35, and 50C) and in water, 1M and 3M OH. Preliminary data obtained at 25C indicated agreement with both model calculations at the 1M OH condition but that the data tended toward the predictions of the SOLGASMIX calculations in water and in 3M OH. The results at 25C and at the other temperatures will be formally evaluated and then converted for use in an ESP data bank. The results remove a deficiency within the ESP software and allow more accurate predictions of the double salt in future simulations applied to the Hanford wastes. |
Subtask 3.6 |
Ceramic regenerative heat-storage device for dioxin control and heat storage. During this reporting period, a computer model for the ceramic heat storage bed was developed. This model predicts the heat up characteristics of a pebble bed matrix as a function of its bed height, the initial gas velocity and temperature, and the pebble size and material. The model will be used for the design of the regenerative heater for our experiment. |
Inquiries may be addressed to: Dr. John Plodinec, Director205 Research Blvd. Starkville, MS 39762-5932 |
Phone: 662-325-2105 FAX: 662-325-8465 Email: dial@dial.msstate.edu |