Contact mechanics is the study of the behavior of solids when they come into contact at one or more points. Contact mechanics research allows for the investigation of tribology, contact stiffness, electrical contact resistance, and indentation hardness. This understanding is required for the safe and efficient design of technological systems. One of the main interesting research observations is the study of contact mechanics behavior between two brass hemisphere with different diameter ratios and friction coefficients, which subsequently becomes the subject of this study. For this study, seven diameter ratios ranging from one- to seven-folds were compared using friction coefficients of 0.05, 0.1, 0.4, and 0.8. Both experiments and simulations were performed to investigate the behavior of the contact mechanics. The experiments and simulation were designed to investigate the effect of friction coefficient and diameter ratio on Von-Misses in the loading process and deformation. The results of the finite element method simulations µ = 0 and lubricated condition experiments are coherent between each other. As a result, it is proven that the coefficient of friction has influenced the unloading deformation and von Mises stress distribution. However, the impact on the deformation ratio with a coefficient of friction from 0.05 to 0.8 does not show a significant difference. The distribution of von Mises stress on diameter ratio 1 showed similar results between the two specimens. Specimen 2 had a wider von Mises stress distribution than specimen 1 at a higher diameter ratio. From diameter ratio 3 to diameter ratio 7, there is a highly localized stress at the edge of the contact area. This region is caused by shear stress as a result of the middle material pushing the surrounding material sideways. When the friction coefficient is increased, the localized stress area decreases, which indicates that the resultant load given is reduced.

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Electrospinning is one of a method for fabricating nanometer to micrometre fibres. Some parameters that affect the formation of nanofibers in an electrospinning method such as solution, process, and environmental parameters. This research aims to synthesize and characterize polyethersulfone/polyacrylonitrile (PES/PAN) nanofibers and to analyze the effect of electrospinning parameters on PES/PAN nanofibers. PES/PAN fibres were prepared by dissolving PES with a concentration of 10% (w/w), 15% (w/w), 20% (w/w), and then added 0,5 gram of PAN. The results of fibre morphology with a variety of solutions showed the PPG1 fibre bead and the fibres for PPG2 and the fibre for PPG3, the morphological results of the PPG2 samples with variations in the tip collector distance indicated the fibre. The results of the diameter analysis showed that the effect of solution variation showed fibre for PPG1, PPG2, PPG3, namely 481 nm, 776 nm, 1339 nm, respectively while the diameter variation of the tip collector distance is 5 cm, 10 cm, 15 cm, namely 1266 nm, 860 nm, 401 nm, respectively and the voltage variation at 10 kV, 12 kV, 14 kV, namely 698 nm, 681 nm, 680 nm, respectively. The results of morphology and diameter show that the solution parameters and the electrospinning process affect the shape and diameter of the fibre. Fabricated fibres can be used as matrices in air filtration systems.