Real-time infrared spectroscopy coupled with blind source separation for nuclear waste process monitoring

On-line infrared absorbance spectroscopy enables rapid measurement of solution-phase molecular species. Many spectra-to-concentration models exist for spectral data, with some models able to handle overlapping spectral bands and nonlinearities. However, model accuracy is limited by the quality of training data used in model fitting. The process spectra of nuclear waste simulants at the Savannah River Site display incongruity between training and process spectra; the glycolate spectral signature in the training data does not match the glycolate signature in Savannah River National Laboratory process data. A novel blind source separation algorithm is proposed that preprocesses spectral data so that process spectra more closely resemble training spectra, thereby improving model quantification accuracy when unexpected sources of variation appear in process spectra. The novel blind source separation preprocessing algorithm is shown to improve nitrate quantification from an R2 of 0.934 to 0.988 and from 0.267 to 0.978 in two instances analyzing nuclear waste simulants from the Slurry Receipt Adjustment Tank and Slurry Mix Evaporator cycle at the Savannah River Site

Understanding morphological evolution of Griseofulvin particles into hierarchical microstructures during liquid antisolvent precipitation

Controlling morphology of active pharmaceutical ingredients (APIs) during crystallization/precipitation is essential for pharmaceutical development since the pharmaceutical powder properties such as solubility, flowability, and dissolution rates are morphology dependent. The objective of this work was to understand the morphological evolution of a poorly water-soluble antifungal drug, griseofulvin (GF), during liquid antisolvent (LAS) precipitation in the presence of ultrasound and additives. GF was found to precipitate as hierarchical structures in the presence of different additives and in the absence of ultrasound. An umbrella-like morphology was observed when hydroxypropyl methylcellulose was used, hexagonal particles elongated along the central axis were obtained in the presence of Tween 80, and the use of polyvinylpyrrolidone yielded long needle-like particles. The most fascinating morphology was observed in the case of bovine serum albumin and no ultrasound, where the GF particles precipitated as six-branched hierarchical structures. Interestingly, the morphology of 6-month-old GF particles reveals that the outline of the overall morphology of initial unfilled skeletons resembled the bipyramidal morphology that would form when particles are completely filled/fused due to Ostwald ripening. The size of GF particles typically varied from 30 to 50 ?m when no ultrasound was used. Time-resolved scanning electron microscopy (SEM) studies imply that interesting morphologies of GF particles observed in the absence of ultrasound could be the result of aggregation and fusion of a large number of small particles formed in the beginning of the precipitation process. These smaller particles fuse to form primary bipyramidal particles which then undergo diffusion-limited growth through Ostwald ripening and secondary nucleation on specific particle faces due to selective adsorption of additives depending on the functional groups present on those particular faces. In contrast to the no ultrasound situation, the use of ultrasound along with the additives resulted in the formation of completely filled octahedron/bipyramidal GF particles irrespective of the additive used. These particles were significantly smaller with sizes ranging from 4 to 6 ?m. Use of ultrasound improves micromixing and alters the particle growth mechanism from diffusion limited to integration controlled resulting in smaller and well-formed GF particles.by Rupanjali Prasad and Sameer V. Dalv

Understanding evolution Of hierarchical structures of a poorly water soluble drug using additives during liquid antisolvent precipitation

by Rupanjali Prasad and Sameer V.Dalv

Precipitation of curcumin by pressure reduction of CO2-expanded Acetone

by Rupanjali Prasad, Rahul Patsariya and Sameer V. Dalv

Quantifying Dense Multicomponent Slurries with In-Line ATR-FTIR and Raman Spectroscopies: A Hanford Case Study

The multiphase nature of slurries can make them difficult to process and monitor in real time. For example, the nuclear waste slurries present at the Hanford site in Washington State are multicomponent, multiphase, and inhomogeneous. Current analytical techniques for analyzing radioactive waste at Hanford rely on laboratory results from an on-site analytical laboratory, which can delay processing speed and create exposure risks for workers. However, in-line probes can provide an alternative route to collect the necessary composition information. In the present work, Raman spectroscopy and attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy are tested on simulants of nuclear waste slurries containing up to 23.2 wt % solids. We observe ATR-FTIR spectroscopy to be effective in measuring the solution phase of the studied slurry systems (3.52% mean percent error), while Raman spectroscopy provides information about the suspended solids in the slurry system (18.21% mean percent error). In-line measurement of multicomponent solids typical of nuclear waste processing has been previously unreported. The composition of both the solution and solid phases is vital in ensuring stable glass formulation and effective disposal of nuclear waste at Hanford. Raman and ATR-FTIR spectroscopies can provide a safer and faster alternative for acquiring compositional information on nuclear waste slurries