Developing a Virtual Flowability Sensor for Monitoring a Pharmaceutical Dry Granulation Line

Current technologies to measure granule flowability involve at-line methods that can take hours to perform. This is problematic for a continuous dry granulation tableting line, where the quality assurance and control of the final tablet products depend on real-time monitoring and control of powder flowability. Hence, a real-time alternative is needed for measuring the flowability of the granular products coming out of the roller compactor, which is the unit operation immediately preceding the tablet press. Since particle analyzers have the potential to take inline measurements of the size and shape of granules, they can potentially serve as real-time flowability sensors, given that the size and shape measurements can be used to reliably predict flowability measurements. This paper reports on the use of Partial Least Squares (PLS) regression to utilize distributions of size and shape measurements in predicting the output of three different types of flowability measurements: rotary drum flow, orifice flow, and tapped density analysis. The prediction performance of PLS had a coefficient of determination ranging from 0.80 to 0.97, which is the best reported performance in the literature. This is attributed to the ability of PLS to handle high collinearity in the datasets and the inclusion of multiple shape characteristics-eccentricity, form factor, and elliptical form factor-into the model. The latter calls for a change in industry perspective, which normally dismisses the importance of shape in favor of size; and the former suggests the use of PLS as a better way to reduce the dimensionality of distribution datasets, instead of the widely used practice of pre-selecting distribution percentiles.

Development of a Virtual Sensor for Real-Time Prediction of Granule Flow Properties

We report progress of an ongoing work to develop a virtual sensor for flowability, which is a critical tool for enabling real time process monitoring in a granulation line. The sensor is based on camera imaging to measure the size and shape distribution of granules produced by wet granulation. Then, statistical methods were used to correlate them with flowability measurements such as ring shear tests, drained angle of repose, dynamic angle of repose, and tapped density. The virtual sensor addresses the issue with these flowability measurements, which are based on off-line characterization methods that can take hours to perform. With a virtual sensor based on real-time measurement methods, the prediction of granule flowability become faster, allowing for timely decisions regarding process control and the supply chain.

Characterizing flowability of granular materials by onset of jamming in orifice flows

This paper describes methods to measure flow rate and jamming onset of granules discharged through a flat-bottom cylindrical hopper with a circular orifice. The intrinsic jamming onset for ideal particles (spherical, monodisperse, smooth) is experimentally measured by two independent methods, with good agreement. For non-ideal particles, the normalized jamming onset increases with elongated granule shape, broadened size distribution and increased friction as measured by the drained angle of repose. An empirical model of the jamming onset is introduced to quantify these effects over the range of materials investigated.  The jamming onset can be used as a measure of differentiation between relatively free-flowing granules.Received: 17 Novembre 2014,  Accepted: 2 March 2015; Edited by: L. A. Pugnaloni; Reviewed by: G. Lumay, University of Liège, Belgium; DOI:http://dx.doi.org/10.4279/PIP.070004Cite as: P Mort, Papers in Physics 7, 070004 (2015)This paper, by Paul Mort, is licensed under the Creative Commons Attribution License 3.0. 

Barriers and gateways: a study of nursing students' utilisation of learning support resources

Many first year nursing students require additional academic support from both their lecturers and learning resources. Anecdotal evidence at an Australian university suggested that 'at risk' students did not follow up lecturer referral. This study identified what learning resources were accessed and what factors influenced students' decisions to follow up or not to follow up lecturer referral. First-year nursing students (n =150) were surveyed towards the end of their second semester regarding their use of learning support services. Twelve students were randomly selected and interviewed regarding their use of learning support and their first year learning experience. Demographic data were analyzed using descriptive statistics. Qualitative data were subjected to content analysis. Results revealed learning support utilisation was related to age and publicity but unrelated to gender or culture. Older students entering through non-traditional entry modes displayed a tendency to self refer to learning support. Younger students (<25 years) often lacked effective learning strategies and were reluctant to access on-campus learning support. For all students positive on and off campus support led to positive outcomes. Faculty and learning support lecturers need to foster integration of learning support for all students and encourage peer-learning partnerships within the foundation subjects.