Canard configuration on fighter planes is essential for regulating flow and the occurrence of vortex interactions on the main wing, one of which is to delay stall. Stall delays are useful when the aircraft is making maneuvering or short-landing. This study observed the effect of canard configuration on various fighter aircraft models. Fighter models represented the different canard configurations, such as Sukhoi SU-30 MKI, Chengdu J-10, and Eurofighter Typhoon. Water tunnels and computational fluid dynamics (CFD) have made it easier to visualize the flow and aerodynamic forces. The results showed that at a low angle of attack (AoA) < 30°, the Chengdu J-10 and Eurofighter models had the highest lift force coefficient (Cl). When at high AoA, Cl’s highest value occurred on the Sukhoi SU-30 model with a value of 1.45 at AoA 50°. Meanwhile, the highest AoA that still had a high Cl value occurred on the Sukhoi SU-30 and Chengdu J-10 aircraft models, namely at AoA 55° with Cl values more than 1.1. The canard position in the upper of the wing would increase the Cl at low AoA, while the parallel canard position could delay the stall.
Currently, there is an outbreak of a new infectious disease in Indonesia, namely coronavirus disease 2019 (COVID-19). This disease is spread quickly through close contact and droplets expelled when coughing, sneezing, talking, or contacting contaminated surfaces. Some effective methods include always wearing a mask outside the house, maintaining a distance of at least 2 meters when interacting with people, and diligently washing hands with soap for at least 20 seconds. The community service program aimed to make portable and hygienic handwashing stations as a form of participation in preventing the spread of COVID-19 in the community. The station is easy to move, and users do not need totouch the faucet and soap dispenser. The user only needs to step on the foot pedal to open the faucet and soap dispenser. Viruses, bacteria, or germs can stick to the handle, and the touchless faucet will minimize contact. This station is expected to prevent the transmission of COVID-19. This community service program was carried out in Gunungkidul Regency, Special Region of Yogyakarta and supported by partners such as, Nglipar I, Ponjong, Tepus 1 and 2, Patuk 1 and 2, Semin 2, Panggang 1 dan 2, Gedangsari 2, and Girisubo Community Health Center. The distribution of the station ran smoothly, and it could be used properly. The Community Health Centers were helped with this program.
Coefficient of friction (cof) is an important variable when dealing with con-tact between mechanical parts. It depends on various tribological variables and the value can be determined only by experiments. Cof correlates with the wear of material and this is a severe problem in biomedical engineering. This research numerically studied the effects of cof between talar and bear-ing in the total ankle replacement (TAR) implants. The aim is to evaluate the contact situations affected by cof. The TAR models consist of cobalt chrome (CoCr) alloy and ultra high molecular weight polyethylene (UHMWPE) bio-materials. Five cof values of the dry, lubricated and frictionless TAR me-chanical contacts under ankle gait load were examined. The models use a fixed 1 mm element size for UHMWPE bearing component and four element sizes for the talar component, range from 1 mm to 0.4 mm. Results show that, 1) higher cof induces higher contact pressure, 2) contact stress is not af-fected by cof, 3) proper talar element size is 0.4 mm and 4) frictionless model can be used for the TAR contact mechanic computation. Frictionless model calculates equal contact stress and lower contact pressures with an error of 2.68 % compared to the smooth model.
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