The choice of ceramic-on-ceramic coupling in total hip prosthesis has advantages over couplings with other combinations of materials that use polyethylene and metal materials in terms of high hardness, scratch resistance, low wear rate, and increased lubrication performance. To reduce the risk of primary postoperative failure, the selection of ceramic materials for ceramic-on-ceramic coupling is a strategic step that needs to be taken. The current study aims to analyze ceramic-on-ceramic coupling with commonly used ceramic materials, namely zirconium dioxide (ZrO₂), silicon nitride (Si₃N₄), and aluminium oxide (Al₂O₃), according to Tressa failure criterion for the investigation of the stress distribution. A two-dimensional axisymmetric finite element-based computational model has been used to evaluate the Tresca stress on ceramic-on-ceramic coupling under gait cycle. The results show that the use of ZrO₂-on-ZrO₂ couplings can reduce Tresca stress by about 17.34% and 27.23% for Si₃N₄-on-Si₃N₄ and Al₂O₃-on-Al₂O₃ couplings, respectively.

Generally, there are two types of working style, i.e., some people work in sitting conditions, and the remaining work mostly in a standing position. For people working in a standing position, they can spend hours in a day doing their work standing. These people do not realize that it can cause medical issues, especially for the feet, namely biometric problems. In addition, several doctors in Indonesia are already aware of this issue and state that the biometric problems faced by those kinds of people can be predicted from the load distribution on the foot. However, the tool used by the doctors in Indonesia to measure biometric problems is not a digital tool. Therefore it is very difficult to measure and predict the biometric problems quantitatively. This study aims to develop a low-cost static load measuring device using force-sensing resistor (FSR) sensors. The measuring instrument is designed in the form of a pressure plate platform which consist of 30 FSR 402 sensors. The sensors are placed right underneath the display area of the foot, 15 sensors on the soles of the left and right feet. Ten students from the Department of Mechanical Engineering, Diponegoro University (five men and five women) were asked to stand on the platform. Each subject also measured foot length (FL) to estimate shoe size, foot area contact (FAC) for validation between genders, and foot type using the digital footprint tools. From the results of measurements obtained for the left foot in the medial mid foot area, i.e., in sensors 5 and 7, not exposed to the load, on almost all subjects except subject number 3 with a load of 0.196 kg on sensor 7. The highest average load occurs in the heel area i.e., sensor 1 measured 0.713 kg and the smallest average load occurs in the five sensors, with 0 kg. A static load gauge that is designed to be used to measure each leg area for subjects with a shoe size of 40–42 with low price to be held in hospital-orthopedic hospitals and biomechanical research centers.

The analysis of normal and pathological variation in human foot morphology is central to several biomedical disciplines, including orthopedics, orthotic design, sports sciences, and physical anthropology, and it is also important for efficient footwear design. A classic and frequently used approach to study foot morphology is analysis of the footprint shape and footprint depth. Footprints are relatively easy to produce and to measure, and they can be preserved naturally in different soils. In this study, we need to correlate footprint depth with corresponding foot pressure of individual using 3D scanner. Several approaches are used for modeling and estimating footprint depths and foot pressures. The deepest footprint point is calculated from z max coordinate-z min coordinate and the average of foot pressure is calculated from GRF divided to foot area contact and identical with the average of footprint depth. Evaluation of footprint depth was found from importing 3D scanner file (dxf) in AutoCAD, the z-coordinates than sorted from the highest to the lowest value using Microsoft Excel to make footprinting depth in difference color. This research is only qualitatif study because doesn’t use foot pressure device as comparator, and resulting the maximum pressure on calceneus is 3.02 N/cm2, lateral arch is 3.66 N/cm2, and metatarsal and hallux is 3.68 N/cm2.

A type of flatfoot can be analyzed accurately using the footprint when a human is standing; however, this method cannot be applied when a human is wearing orthotic shoes. This study aims to analyze flatfoot using the rearfoot angle (RFA) measurement. The result is then compared to a footprint measurement known as Cavanagh’s Arch Index (AI). A total of 31 static footprints of the participants consisting of 14 males and 17 females aged 18 to 25 years were collected. According to Cavanagh’s AI as a gold standard, the correlation equation was obtained as RFA = 46.04AI − 6.41 and RFA = 45.32AI − 6.26 for left and right foot, respectively. The correlation coefficient R² for the left and the right foot is 0.63 and 0.73, respectively. Other statistical analyses using ANOVA and t-tests are presented in this paper. The correlation results obtained from this study are necessary for estimating the reduction in the degree of flatfoot when using orthotic shoes, which is difficult to calculate using the typical AI method from footprint measurements.

Federal Motor Vehicle Safety Standard (FMVSS) mengklasifikasikan kendaraan bis dan truk (trailer dan container) sebagai heavy duty vehicle dimana rem, kopling, dan ban adalah komponen-komponen yang harus diperiksa secara rutin karena berkaitan dengan keamanan dan umur pemakaiannya yang relatif pendek. Sebagai komponen utama material gesek kampas rem memang harus bagus dan harus lolos serangkaian test sebagaimana diatur dalam berbagai standard yaitu SNI 09-0143-1987, ASTM G0115-04, ASTM D3359-02. Tetapi menurut The American Public Transportation Association (APTA BTS-SS-RP-003-07), kinerja sistim pengereman bis dan truk tidak semata-mata ditentukan oleh kualitas material kampas rem saja tetapi juga oleh kondisi brake shoe dan prosedur pemasangan (rebuild) kampas pada brake shoe. Dari hasil survey banyak pengusaha transportasi bis di Indonesia yang mengabaikan prosedur rebuild kampas rem yang telah distandarkan oleh APTA BTS-SS-RP-003-07 tersebut. Akibatnya kampas rem cepat aus, rem terkunci, dan yang paling parah adalah rem blong (rem tidak berfungsi). Fokus utama penelitian ini adalah mengkaji kemungkinan kerusakan brake shoe assembly (komponen rakitan kampas rem) saat pengereman yang berpotensi menyebabkan terjadinya kegagalan fungsi pengereman pada bis/truk.

RTV 10A silicone rubber composites have many applications in forming many medical products and one of the recent applications is for orthotic insoles. This is because the RTV silicon rubber has excellent flexibility, elasticity, and resistance against splitting. However, these mechanical...