This paper presents an application of topology optimization and response surface method to optimize the geometry of a bicycle crank arm and the experimental validation of it. This is purposely to reduce the crank arm mass and create a preliminary design of a lightweight structure necessary for the high-performance bicycle development. A three-dimensional bike crank arm model was made in the SpaceClaim software followed by a static finite element analysis using ANSYS Workbench 2019 R1. A multiple cycling load was applied simultaneously in seven crank angles of 30, 45, 60, 90, 120, 135, and 150° relative to the horizontal position to create the multiple loads to the crank. From there, topology optimization was then conducted to investigate the effect of mass constraint, stress constraint, angle of cycling, and crank materials on the topological pattern result. To minimize stress concentration at corners, a shape optimization using the response surface method was conducted and obtained the final geometry. From the result, it is shown that both optimization methods not only successfully reduce the crank arm mass and provide several optimum design options but also are able to reduce the maximum stress in the crank arm up to 20% after the optimization process. The experimental validation using a newly developed wireless measurement system shows a considerable agreement to the numerical results.

In recent years, the ministry of education has adopted policies aimed at enhancing the consistency and efficacy of the teaching and learning process. In the midst of the Covid-19 pandemic, the implementation of different alternatives to the current teaching and learning mechanism is extremely crucial. With the migration of the current education online, AR is viewed to be a suitable and relevant alternative to be implemented. However, study on teacher readiness to adopt AR in education is still absent. Therefore, there is a need to investigate teacher's ICT skills and their readiness in deploying AR in teaching and learning. This research uses quantitative study and survey as the research methodology with 96 teachers involved as a participant. The data analysis is performed using descriptive analysis with the help of SPSS software. The findings showed that teachers in this research show a minimum to moderate level of expertise skilled in handling different ICT aspects. In addition, the research has also shown that teachers in this study show less familiarity with AR technology. The significance of this study is able to provide a set of empirical results that is beneficial for further education planning by the government.

Peningkatan kebutuhan energi nasional membuat industri minyak dan gas menjaga keandalan peralatannya. Gas Turbine Compressor (GTC) Centaur 50 di PT. XYZ merupakan salah satu peralatan vital dalam operasi produksi, sehingga diperlukan metode tepat untuk menjaga keandalannya. Metode Reliability Centered Maintenance (RCM) memiliki prioritisasi jenis perawatan yang tepat. Analisa keandalan menggunakan perhitungan kuantitatif dari data handbook OREDA (Offshore Reliability Data), manual book GTC Centaur 50, dan data aktual lapangan. Berdasarkan hasil analisa pendekatan Failure Mode Effect Criticality Analysis (FMECA) dan perhitungan Risk Priority Number (RPN) komponen utama penyebab kegagalan yang dibuat dalam diagram pareto, maka terdapat 20% kegagalan fungsi terbesar (27 kegagalan fungsi). Serta 26 kegagalan fungsi tambahan dari tim maintenance lapangan. Sistem perawatan GTC di PT. XYZ digolongkan dalam 14 sub-system, dimana sub-system tersebut kegiatan perawatannya minimal per 8000 jam berdasarkan RCM II Decision Worksheet yang meliputi 134 program perawatan (scheduled on condition monitoring, scheduled restoration, scheduled discard, failure finding, run to fail). Berdasarkan pendekatan Maintenance Value Stream Mapping (MVSM) dengan siklus plan-do-check-action (PDCA) pada siklus do terdapat Non Value Added pada “eksekusi pekerjaan”. Dengan merekomendasikan mempersingkat menjadi maksimal 48 – 72 jam dengan utilisasi man power lapangan. Sehingga dengan durasi lebih pendek maka LPO (Loss Production Opportunity) dapat diminimalisir.

The automotive industry has continuously innovated drive systems. Among various types, Front Wheel Drive (FWD) and Rear Wheel Drive (RWD) systems are widely used. This research examines the influence of these systems on acceleration and deceleration performance through field tests conducted on public highways. Five speed variations—40, 60, 80, 100, and 110 km/h—were tested for acceleration and deceleration. Results indicate RWD vehicles outperform FWD vehicles in acceleration due to the rear location of the drive wheels, providing superior propulsion. Conversely, FWD vehicles demonstrate better deceleration performance, attributed to shorter braking distances and improved braking efficiency.

Harmonic wave propagation through a novel metasurface design is presented in this paper. The metasurface is formed by using the Helmholtz resonator as the cells shape design since such resonator has uniqueness and advantageous performances. The study is conducted both numerically using the finite element method and experimentally using specific measurements to validate the numerical results. Parametric studies of the selected variables are also conducted to obtain broader information on the performance. From the result, it is found that the new proposed metasurface design has the potential to be implemented in future engineering practices.

Decay Curve Analysis of a Damped Vibration System with Multi-force Perturbations