Abstract: A process for on-line density measurement for a hydrocarbon fluid. The hydrocarbon fluid is caused to flow through first and second density sensors arranged in series. The first density sensor has a first temperature and the second density sensor has a second temperature, defining a temperature difference between the first temperature and the second temperature. A first density measurement and second density measurement are received from the first and second density sensors, respectively. A temperature conversion factor is determined. The first density measurement or the second density measurement is corrected using the determined temperature correction factor to provide a temperature-corrected density measurement.

Abstract: A system for obtaining reliable data from a chemical sample for at least one variable environmental condition utilizing a photometer. The photometer obtains sample characteristic data at a plurality of discrete wavelengths. The reliability of the data is determined by obtaining a training set of data, and obtaining a number representing the variation between the mean center of the training set of data and the data representing the sample characteristic obtained by the photometer. Such number represents the basis of determining outliers of the data representative of the reliability of the data.