The assessment of powder streams, regarding their homogeneity and the occurrence of impurities and agglomerations, is a basis for successful process and environmental monitoring. Diffuse reflectance ...near-infrared imaging is a high-speed, noninvasive in-line monitoring technique. It allows for acquiring time- and spatially-resolved spectra at short time intervals and at high spectral resolution, which is preconditioned for real-time process monitoring. In this study, a push-broom near-infrared spectral imaging system was used to spatially monitor the (in-)homogeneity and API (active pharmaceutical ingredient) distribution in flowing powders coming from a feeder. Partial least squares regression was used to develop a model for the quantification of the individual mixture ingredients. Moreover, significant influences of the feeder and the particle properties on the ingredients distributions were found. The ultimately developed chemical images provide chemical information about the single mixture components and their spatial distributions.
We present a general performance measure (information loss) for associative memories based on information theoretical concepts. This performance measure can be estimated, provided that mean values of ...observables have been determined for the associative memory. Then the estimation guarantees a minimal association quality. The formalism allows the application of the performance measure to complex systems where the relation between input and output of the associative memory is not explicitly known. Here we apply our formalism to the Hopfield model and estimate the storage capacity alpha(c) from the numerically determined information loss. In contrast to other numerical methods the whole overlap distribution is taken into account. Our numerical value alpha(c)=0.1379(4) for the storage capacity in the Hopfield model is below numerical values obtained previously. This indicates that the consideration of small remnant overlaps lowers the storage capacity of the Hopfield model.
