Deep Insights into Heavy Oil Upgrading Using Supercritical Water by a Comprehensive Analysis of GC, GC-MS, NMR, and SEM-EDX with the Aid of EPR as a Complementary Technical Analysis.

Upgrading of heavy oil in supercritical water (SCW) was analyzed by a comprehensive analysis of GC, GC-MS, NMR, and SEM-EDX with the aid of electron paramagnetic resonance (EPR) as a complementary technical analysis. The significant changes in the physical properties and chemical compositions reveal the effectiveness of heavy oil upgrading by SCW. Especially, changes of intensities of conventional EPR signals from free radicals (FRs) and paramagnetic vanadyl complexes (VO2+) with SCW treatment were noticed, and they were explained, respectively, to understand sulfur removal mechanism (by FR intensity and environment destruction) and metal removal mechanism (by VO2+ complexes' transformation). For the first time, it was shown that electronic relaxation times extracted from the pulsed EPR measurements can serve as sensitive parameters of SCW treatment. The results confirm that EPR can be used as a complementary tool for analyzing heavy oil upgrading in SCW, even for the online monitoring of oilfield upgrading.

Peak window correlation method for drug screening using Raman spectroscopy.

Modern portable and hand-held Raman spectrometers that recently have become widespread in drug quality screening have good reproducibility and are able to detect small concentrations of substances in mixtures of several components or distinguish compounds similar in structure and having minimal differences in spectrum with appropriate mathematical processing methods. Among other spectrum comparison approaches, the peak search at their location is the most important task of spectral imaging of the studied samples. In this work, the Raman spectra of liquid drugs involved in the governmental non-destructive quality screening program performed by 8 mobile laboratories equipped with Raman spectrometers with uncooled detector and a 532 nm laser were compared with reference sample spectra using the peak windows correlation (PWC) algorithm developed in this work by authors. The proposed method provides accurate identification, detection of composition changes, and presence of foreign components in drugs formulations even if their contribution to the overall signal is negligible. The spectral correlation method called hit-quality index (HQI) method conventionally used for such portable spectrometers was specified as comparative method.