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In past few decades, a lot of research has been done in the field of machining to improve the quality of machined surface. Out of these machining operations, drilling is widely used in the areas of marine and aerospace for assembly requirements. Titanium alloy Ti-6Al-4V, owing to its vast applications, is regarded as an important material for these industries. Ti-6Al-4V is categorized as difficult to machine material. Based on above stated facts, an experimental study was conducted on the dry drilling of Ti-6Al-4V. The objective of this study was to establish the correlations between drilling parameters such as feed rate and spindle speed, and quality of machined surface which is evaluated in terms of drill hole diameter deviation, exit burr height and surface roughness.

A novel method was proposed to design the structure of a bone tissue engineering scaffold based on triply periodic minimal surface. In this method, reverse engineering software was used to reconstruct the surface from point cloud data. This method overcomes the limitations of commercially available software packages that prevent them from generating models with complex surfaces used for bone tissue engineering scaffolds. Additionally, the fluid field of the scaffolds was simulated through a numerical method based on finite volume and the cell proliferation performance was evaluated via an in vitro experiment. The cell proliferation and the mass flow evaluated in a bioreactor further verified the flow field simulated using computational fluid dynamics. The result of this study illustrates that the pressure value drops rapidly from 0.103 Pa to 0.011 Pa in the y-axis direction and the mass flow is unevenly distributed in the outlets. The mass flow in the side outlets is observed to be approximately 24.3 times higher than that in the bottom outlets in the range 6.13 × 10 −8 kg/s to 1.49 × 10 −6 kg/s. Moreover, the mass flow in the bottom outlets decreases from the center to the edge, whereas the mass flow in the side outlets decreases from the top to the bottom. Importantly, although the mean value of wall shear stress is significantly more than 0.05 Pa, there is still a large area with a suitable shear stress below 0.05 Pa where most cells can proliferate well. The result shows that the inlet velocity 0.0075 m/s is suitable for cell proliferation in the scaffold. This study provides an insight into the design, analysis, and in vitro experiment of a bone tissue engineering scaffold.

Biometrics deals with the recognition of humans based on their unique physical characteristics. It can be based on face identification, iris, fingerprint and DNA. In this paper, we have considered the iris as a source of biometric verification as it is the unique part of eye which can never be altered, and it remains the same throughout the life of an individual. We have proposed the improved iris recognition system including image registration as a main step as well as the edge detection method for feature extraction. The PCA-based method is also proposed as an independent iris recognition method based on a similarity score. Experiments conducted using our own developed database demonstrate that the first proposed system reduced the computation time to 6.56 sec, and it improved the accuracy to 99.73, while the PCA-based method has less accuracy than this system does.

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