Metal oxide semiconductor has attracted so much attention due to its high carrier mobility. Herein, thermoelectric study of nanocrystalline SnO2 through a simple co-precipitation method is conducted to enhance the Seebeck coefficient (S). X-ray diffraction, thermogravimetric analysis (TGA), resistivity (r), Seebeck coefficient (S), and power factor (PF) measurements are conducted to analyze the thermoelectric properties of the material. The measurements show that there are two interesting results, which are the unusual resistivity behavior and the high value of the S. Resistivity behavior shows a non-reflective intermediate semiconductor-metals behavior where the turning point occurs at 250 o C. This behavior is strongly correlated to the surface oxide reaction due to annealing temperature. The maximum S likely occurs at 250 ºC, since the curve shows a slight thermopower peak at 250 ºC. The value of the S is quite high with around twenty times higher than other publications about SnO2 thermoelectric material, this happens due to the bandgap broadening. The energy gap of SnO2 calculated using density functional theory (DFT), which was performed by Quantum Espresso 6.6. The result shows that there is a broadening energy gap at different momentum or wave factor. Nanocrystalline semiconductors material is giving an impact to increase the width of bandgap due to quantum confinement and could enhance the thermopower especially in SnO2 nanocrystalline
<p>An experimental validation of flatness measurement based on image processing technique has been performed. The purpose of this study is to know the performance of the image processing technique in the flatness measurement. In addition, this technique will be used as development of current measurement technique that is performed manually. The advantage of using this method is that in the future the measurement system will run semi-automatically, so it can increase the capacity. This study is used 3 samples of optical flat with different in diameter (i.e. 25 mm, 45 mm, and 75 mm). The validation has been performed by comparing measurement results of the image processing technique and the manual technique through degree of equivalence evaluation. The error numbers based on the degree of equivalence criteria between the image processing technique and the manual technique for the flatness measurement of 25 mm, 45 mm, and 75 mm are 0.02, 0.09, and 0.11 respectively. According to those error numbers, the image processing technique measurement results is in agreement with the manual technique. Moreover, those results have validated that the image processing technique has good performance and can potentially be implemented to the flatness measurement.</p>
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