Objective: This research aims to observe the extent to which several surface treatment techniques increase the surface roughness of titanium alloy implants which was manufactured via electrical discharge machining (EDM). The effects of these techniques were also observed to decrease the Cu content on the implant surface. Materials and Methods: In this research, ultrasonic cleaning, rotary tumbler polishing, and brushing were employed as techniques to increase the roughness of a titanium implant which was manufactured via EDM, to the moderately rough category, and to reduce the contaminant element deposited on its surface. An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay test was also used to observe the effect of these engineered specimens with respect to mesenchymal stem cells’ proliferation. Results and Discussion: The results show that ultrasonic cleaning and rotary tumbler polishing created a significant increase (90% and 67%, respectively) in the surface roughness. On the other hand, brushing was shown to be the best benchmark for reducing the contamination of Copper (Cu). Furthermore, rotary tumbler polishing and brushing can increase the percentage of living cells compared to the original surface EDM specimens. Conclusion: All micro-finishing methods that were employed are able to increase the surface roughness of Ti alloy based-implant to moderately rough category.

The presence of rehabilitation tools is essential to more rapidly cure hand muscle disorders of people affected by stroke. One of the tools is a dynamic splint that is fit-sized, lightweight, comfortable to wear, and easy to operate. The paper proposes the design and analysis of new dynamic splints based on pulley rotation as a rehabilitation device for finger extension after stroke. This device consists of the main splint, the pulley, the locker, the finger handles, the ball bearing, and the fishing line. To lock and stop pulley turning, the locking system is designed to complement it which is also the most important mechanical segment. The shear stress of the pulley was 0.026 N/mm2. The deformation, stress, and strain energy of the locking system section were analyzed by the finite element method. The results showed that the deformation distribution around the locker section was at 0.1-0.15 mm intervals. The maximum stress 25.0786 MPa, which is still inferior to the yield strength of ABS Material (28.5 MPa). The safety factor of the structure is about n = 1.14. The largest strain energy was 0.2856 mJ at the same place as with the maximum stress which was close to the conical end of the locker. The correlation between stress-strain energy and moment was linear as well. In future work, a prototype will be fabricated using 3D printers, and it will be applied to the stroke patient. In addition, the therapies will be involved to assess the improvement of the finger extension of stroke patients.

Miniplate plays an important role as one of the implant components used as a rehabilitation device for a post-fracture finger. In this study, an analysis was carried out to determine the strength of the miniplate design made from Ti-6Al-4V titanium alloy material. Simulation and analysis were carried out using the finite element method. The given input for modeling tensile and bending loads determined von Mises stress, kinetic energy, strain energy, and internal energy. The analysis showed that uneven von Mises stress and strain distribution have occurred. The critical concentration of stresses was located at the center of the miniplate and these values were a lot lower than the yield stress of Ti-6Al-4V.

This study analyzed the design performance of SS316L-based plate implant for fibula restoration using a Finite Element Analysis approach. The simulated model design has dimensions of 35 x 5 x 1.5 mm and five holes with 2-3 configuration. The results of the bending test simulation showed that the values for both displacement and Von Mises stress that occurred (0.008 mm and 116 MPa of each) were still considerably below the yield stress of the SS316L material. The same results were also shown in the tensile test simulation, although the clamping setting on the plate was changed on the other side. From this finite element analysis approach, the SS316L-based five-hole plate implant design has a fairly good strength performance as a fibular bone-implant restoration product.

One of the weaknesses of diesel engines that most users complain about is the vibration and the noise. Therefore, it is very important to know the noise level of an engine in a room to consider the allowed duration of the exposure time, which is the aim of this study. The instrument used in this study was the Sound Level Meter, by first determining the radius of the hemisphere used in determining the location for the data collection. The measurement was carried out four times, where the largest value was considered as the main data, at four points. The result in this study indicated that the noise level of the diesel engine with a speed of 1100 rpm was 92.805 dBA with the background noise in the diesel engine room of 51.6 dB. Based on government regulations, the maximum exposure time to the noise at this level is 2 hours.