Marko Paavola

Continuous direct tablet compression: effects of impeller rotation rate, total feed rate and drug content on the tablet properties and drug release

Context: Continuous processing is becoming popular in the pharmaceutical industry for its cost and quality advantages. Objective: This study evaluated the mechanical properties, uniformity of dosage units and drug release from the tablets prepared by continuous direct compression process. Materials and methods: The tablet formulations consisted of acetaminophen (3–30% (w/w)) pre-blended with 0.25% (w/w) colloidal silicon dioxide, microcrystalline cellulose (69–96% (w/w)) and magnesium stearate (1% (w/w)). The continuous tableting line consisted of three loss-in-weight feeders and a convective continuous mixer and a rotary tablet press. The process continued for 8 min and steady state was reached within 5 min. The effects of acetaminophen content, impeller rotation rate (39–254 rpm) and total feed rate (15 and 20 kg/h) on tablet properties were examined. Results and discussion: All the tablets complied with the friability requirements of European Pharmacopoeia and rapidly released acetaminophen. However, the relative standard deviation of acetaminophen content (10% (w/w)) increased with an increase in impeller rotation rate at a constant total feed rate (20 kg/h). A compression force of 12 kN tended to result in greater tablet hardness and subsequently a slower initial acetaminophen release from tablets when compared with those made with the compression force of about 8 kN. Conclusions: In conclusion, tablets could be successfully prepared by a continuous direct compression process and process conditions affected to some extent tablet properties.

Wireless monitoring of a steam boiler - performance measurements in industrial environment

Electromagnetic interferences and other disturbances restrict the coverage area and reliability of wireless sensor networks (WSN) in industrial environment. The need for empirical data to provide evidence of these disturbances has also been addressed. This paper presents results of screening tests performed in the steam boiler process to find out the effect of some factors on jitter variation. The effect of factors is estimated from coefficients of a partial least squares model, which was fitted to on the basis of a statistical quantity calculated from jitter variation data. The quantity used, Pearson mode skewness of histogram frequencies, was selected by comparing different statistical techniques. The selected quantity seems to be able to identify some candidates for more detailed tests, namely distance from nodes to the gateway, mutual interference, sampling interval, number of nodes, frequency converter/pumping installation and the block. The results show that the effect of the single Bluetooth and WLAN transmission is insignificant compared to other factors.

Comparison of three change detection algorithms for an electronics manufacturing process

In a sequential manufacturing process, a product proceeds through different manufacturing stages. At these stages, sensors monitor the features of the product. In this paper, the information produced by the sensors is employed to detect abrupt changes in process variables. The developed algorithms contribute to an on-line application to a manufacturing system. A literature survey revealed the most common methods utilized in change detection. On-line applicability and transferability to new manufacturing lines are the most important features for real applications. During both on-line and off-line tests, some of the presented methods showed satisfactory results. Real-time, on-line manufacturing environment sets also its requirements for the applications. In the future, the possibility of combining expert knowledge with the aforementioned methods is the crucial point to study. The information thus received has usage in the preventive maintenance and quality control.

Monitoring of Automated Screw Insertion Processes-A Soft Computing Approach

Abstract A soft computing monitoring approach for automated screw insertions is presented. A model based monitoring method is developed with systematically collected experimental data and fundamental process knowledge to verify the quality of assemblies. The model for quality monitoring is based on Linguistic Equations (LE)-a non-linear scaling framework for model variables. Fuzzy reasoning and basic statistical methods are combined to interpret the model residuals and faults. Preliminary tests indicate that the proposed method could successfully cope with changes in manufacturing parameters. Based on the results, the method seems to provide valuable information for quality control of the screw insertion task.

Pilot Plant Simulation as a Tool for More Efficient Mineral Processing

Abstract This paper describes a static flow sheet simulation model developed for the pilot scale mineral beneficiation plant taken recently into use at University of Oulu, Finland. The mini-pilot plant aims to serve as a research platform for students and researchers from universities, mining companies, and other organizations in the field of mining and mineral engineering. Currently, the mini-pilot plant is set up according to the concentrator plant at the Pyhasalmi deposit but can be configured for different types of ores and beneficiation processes as well. The simulator is built using the HSC Sim® simulation software. The simulator will support research and development of the new mini-pilot line. It can also be used in process design and optimisation. This paper presents preliminary results demonstrating the promising potential of the simulation model for replicating the pilot process behaviour. The future aim is to convert the static model into dynamic operating mode and study different control scenarios of mineral beneficiation plants using the simulator.

Some factors affecting performance of a wireless sensor network — entropy-based analysis

Electromagnetic interferences and other disturbances in industrial environment may decrease the performance of wireless sensor networks. However, the lack of empirical results providing proof for these arguments is evident. In this paper, analysis results of systematic experiments carried out for potential, disturbing factors in industrial environment are presented. Moreover, a novel entropy-based approach to measure changes in jitter variation is introduced. The selected approach performed well, being able to point out statistically significant sources of disturbances.

Information Theoretic Approach to Improve Performance of Networked Control Systems

Networked control systems (NCS) could be utilised in several industrial applications. However, the variable time delays introduced by the network impair the NCS performance, resulting even in the instability of the controlled process. To mitigate the delay problems, the advantage is taken from model-based, adaptive controllers. This calls for an efficient approach for on-line analysis of measurements applied to update the controller state in NCS. The paper introduces a new adaptive Model Predictive Controller (MPC) capable of compensating for variations in measurement and actuating delays. Weighting factors for delayed measurements and actuators are adjusted based on normalised version of mutual information that is calculated using a procedure described in the paper. The method is superior compared with other, more usual, metrics.