Browsing by Subject "Young's modulus"

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  • Palomäki, Emmi (Helsingfors universitet, 2012)
    3D-imaging is based on combining two or more pictures to form one three-dimensional picture. Most of the methods used provide only surface pictures, but tomography acquires also information about the inside-structure of investigated material. Young's modulus is a method, which has been used for long time to determine toughness hard materials, such as steal. In traditional method a beam-shaped piece is bent. When the size of piece, used force and amount of bending are known, Young's modulus of piece can be calculated. Although the method has traditionally been used to research very hard materials, it has been applied without changes with pharmaceutical materials. It is, however, open to the question whether or not the method is appropriate for those materials. There are also methods to determine Young's modulus based on compressing a tablet or using ultrasound. Determining tablet's toughness with ultimate strength test is complicated because it breaks tablet. For that reason it would be good to find compensatory methods to measure strength of tablet. The aim of the study was to validate Flash Sizer 3D appliance, which is used in 3D-imiging. Another goal was to investigate possible correlations between 3D-imiging, Young's modulus and traditional ultimate strength method. Lastly, the feasibility of Young's modulus as a substitute for traditional ultimate strength measurement in self life studies was investigated. Flash Sizer 3D was validated by measuring particle size distribution of pellets, which were made of microcrystalline cellulose (Cellets). Sizes of the investigated pellets were 100 µm, 200 µm and 500 µm. Also binary mixture of 100 µm and 200 µm was investigated. From microcrystalline cellulose was made tablets and 3D-pictures were taken. Ultimate strength test was made for half of the tablets. Young's modulus was measured from half of the tablets in tableting day, day after that and nine days after tableting. Results show that Flash Sizer 3D is suitable for investigating bigger Cellet. With smaller particles distinguishing of tablets wasn't probably good enough. Still it seems to be quite good method to determine surface roughness of tablet. Young's modulus seems to be very promising as compensating method for traditional ultimate strength measurement. In future in self life studies tablets hardness might be able to investigate by measuring Young's modulus and not measuring ultimate strength. If correlation between Young's modulus and solubility meets the case, Young's modulus might also replace also solubility measurements in self life studies.