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Browsing by Subject "jauheseos"

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  • Kokkonen, Niina (2011)
    Segregation or demixing of particle systems is a phenomenon where one component of a homogeneous powder mixture tends to separate from the other components. The segregation tendency of powder depends on the characteristics of particles, environmental conditions and interactions between particles. A huge number of segregation mechanisms are presented in literature and even small differences between the properties of particles and particle interactions can lead to a completely different segregation mechanism. The segregation phenomenon is very essential from the perspective of pharmaceutical industry. However, the phenomenon is not yet sufficiently well known in order for segregation to be systematically avoided. Current research on segregation is largely based on learning through trial and error. Therefore, innovative research methods are needed to understand the true segregation phenomenon. The purpose of the experimental part was to develop and basic test the method of testing the segregation behavior of different particle systems and use this method to examine the segregation behavior of pharmaceutical mixtures of granules and pellets. The aim was to prove that the operating principle of the developed Babel-device is suitable for examining the segregation behavior of particle systems, but the trials carried out mainly consisted of method and device testing. The problems were composed of the limitations imposed by the Babel-device, particle electrification and particle interactions. Linear approaches used were insufficient for creating segregation by the Babel-device. Convection resulting from vertical shaking prevented the generation of segregation. In conclusion, we can say that the Babel-device measures well and reproducibly, and it is able to distinguish different particle sizes and different particle size distributions from each other. The development aim of the device would be to obtain a more visible segregation in the powder mixture as a result of shaking. Thus, we would be able to draw conclusions from the segregation behavior of the powder mixture and the prevailing segregation mechanisms in the system. Further development of the device and the method could provide useful additional information which would contribute to better understanding of the phenomenon of segregation.