Student Abstracts: Chemistry at BNL

Correction of the Dispersed Input Function Produced by the Automated Blood Sampling System. . SARAH CUNNIFF (St. Joseph's College, Patchogue, NY 11772) DAVID SCHLYER (Brookhaven National Laboratory, Upton, NY 11973) .
An automated blood sampling system (ABSS) is often used in congruent with a PET scanner, so that physiological information can be obtained. However, during the process of extracting blood from a patient, the input function is slightly distorted by the ABSS. In order to ascertain the original input function after dispersion, the amount of dispersion that is occurring has to be calculated and then subtracted from the ABSS input function. In determining the amount of dispersion that is created we conducted a series of experiments using the ABSS and radioactive isotopes. Once we computed the amount of dispersion we mathematically manipulated this data into a matrix form. It was established that the inverse of the new dispersion matrix had to be computed and multiplied by the ABSS input function in order to attain the original input function. A computer program was written to perform matrix inversion, so that the inverse of this new dispersion matrix could be computed and then multiplied by the ABSS input function. By doing this, we were successful in mathematically subtracting the dispersion that had been created from the automated blood sampling system and created a sharpened, more accurate input function.

CO2 Interaction with Cation-exchanged Zeolites.. DIAN MCKENZIE (York College, Queens, NY 11451) ETSUKO FUJITA AND JON HANSON (Brookhaven National Laboratory, Upton, NY 11973) .
The emission of carbon dioxide into the atmosphere is one of the most serious problems with regard to the greenhouse effect. The reduction of carbon dioxide is of special interest. One approach to carbon dioxide reduction is the usage of cation-exchanged zeolites. Titanium Y zeolite, cesium Y zeolite, potassium Y zeolite, and lithium Y zeolite were prepared by ion-exchanging commercial sodium Y zeolite for studies by time resolved in-situ synchrotron X-ray powder diffraction. A series of time-resolved powder diffraction patterns were obtained for all the prepared zeolites before and during dehydration, and during and after dosing with CO2. The powder patterns for the dehydrated zeolites show an increase in the intensity of the lowest order reflection (111) due to less electron density in the supercages. The powder patterns also show a decrease in intensity of the 111 reflections during dosing of CO2 on all the dehydrated zeolites. The changes to the powder patterns for CO2 dosed zeolites are consistent with cation migration and CO2 binding. Difference Fourier electron density map data of dehydrated Ti Y suggest that there is electron density in SI, SI', and SII cation sites. Preliminary analysis of the refinement data in the range 200-376 oC indicates less total charges for titanium than expected. However the charge on titanium.is consistent with +4.