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Effects of Supplier-Manufacturer Relationships on Supply-Chain Performance of Manufacturing Industries in Indonesia Hidayat, Rachmad; Hudha, Khisbullah; Akhmad, Sabarudin
Makara Journal of Technology Vol. 19, No. 2
Publisher : UI Scholars Hub

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Abstract

The present study describes the relationships between commitment, communication, satisfaction, trust, relationship quality with suppliers, and supply-chain performance. The population of the study was manufacturing companies in Indonesia. Respondents were the chief executive officers or corporate secretaries or the designated managers involved in strategic decision making. Samples were taken by using a proportional area random sampling technique. Structural Equation Modeling (SEM) was used for analysis. Results of both direct and indirect testing of hypothesis indicated two hypotheses of positive and significant effects and nine hypotheses of positive but insignificant effects. Those hypotheses of positive and significant effects were the direct effects of trust on supply-chain performance and the direct effects of relationship quality on supply chain performance.
Enhanced Modeling of Crumple Zone in Vehicle Crash Simulation Using Modified Kamal Model Optimized with Gravitational Search Algorithm Zubir, Amrina Rasyada; Hudha, Khisbullah; Kadir, Zulkiffli Abd; Amer, Noor Hafizah
Automotive Experiences Vol 6 No 2 (2023)
Publisher : Automotive Laboratory of Universitas Muhammadiyah Magelang in collaboration with Association of Indonesian Vocational Educators (AIVE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.9289

Abstract

The effectiveness of a vehicle crash system depends on how well it can simulate the behavior of a real vehicle in a crash scenario and accurately identifies the correct working limits of the model parameters, including mass, spring, and damper. Therefore, this study explores the modelling vehicle front crumple zone to represent the behaviors of real crash scenario. The modelling process using Kamal approach is used to develop a precise vehicle crash model for analyzing the impact of a collision on both the vehicle and its passengers. In this study, a complex mass-spring-damper system representing the front crumple zone of an actual car is re-designed to modify the existing vehicle crash model. The gravitational search algorithm (GSA) is implemented in the simulation model's code to obtain optimized values of damping coefficient (c) and spring constant (k). The simulation results show that the deformation response of crumple zone and the deceleration response of vehicle body match the experimental results, indicating the model's accuracy. Additionally, this study investigates the effects of varying the GSA parameters' number of agents (N), the beta parameter (β), and the gravitational constant (G) to improve the model's accuracy by minimizing the root mean square error (RMSE) between model response and crash test data. The optimal GSA parameter chosen in this study were N = 50, β = 0.3, and G = 20 with the lowest RMSE of 22.3874, 22.26664, and 23.86638 respectively.
Verification of a 3-Degree-of-freedom Bus Handling Model Due to Steering Wheel Input Hakima, Muhammad Akhmal; Aparowa, Vimal Rau; Abd Kadir, Zulkiffli; Sakundarini, Novita; Hudha, Khisbullah; Amer, Noor Hafizah
SINERGI Vol 29, No 2 (2025)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2025.2.022

Abstract

This paper discusses about the development and modeling of a 3-DOF (Degrees of Freedom) bus handling model in response to steering wheel input from the driver. It includes all the relevant mathematical equations. The handling model was created using MATLAB/Simulink, incorporating parameters from TruckSim data to accurately represent the bus. The simulation results were verified by comparing them with TruckSim responses from two test procedures namely double lane change and single lane change tests. The comparison focuses on trends, magnitudes and percentage differences between the developed model and TruckSim results. In the double-lane change test, the largest percentage difference observed was 7%, while the smallest was 0.5% for yaw rate and longitudinal acceleration, respectively. In the single-lane change test, the largest percentage difference was 7.27% for lateral acceleration, and the smallest was 1.5% for yaw rate. The verification indicates that the simulation model closely aligns with TruckSim trends and can be effectively used for further study of bus dynamics in various scenarios.
Plasma Enhanced Ionic Liquid Catalysis for the Production of Biodiesel from Chicken Skin Elsheikh, Yasir Ali; Al Mahri, Hamad; Al Mamari, Asma; Hudha, Khisbullah
Automotive Experiences Vol 8 No 2 (2025)
Publisher : Automotive Laboratory of Universitas Muhammadiyah Magelang in collaboration with Association of Indonesian Vocational Educators (AIVE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.13397

Abstract

Biodiesel production has emerged as a promising area of alternative fuel development, though challenges remain in sourcing cost-effective raw materials and selecting effective catalysts. This study investigates the production of biodiesel from chicken skin fat using two distinct catalytic methods. In the first method, transesterification was catalyzed by trioctyl ammonium hydrogen sulfate (Oct3AMHSO4) at concentrations ranging from 3-6 wt%. In the second method, the same catalyst was combined with plasma to enhance the reaction. The first method yielded only 35% biodiesel with 3.5 wt% Oct3AMHSO4, while the second method, under identical conditions, showed a significant improvement, achieving a 97.4% yield. The impact of temperature variations (40-80°C) was also explored with different catalyst concentrations (3-6 wt%). Increasing the catalyst concentration to 3.5% and raising the temperature to 55°C resulted in a notable yield improvement. However, further increases in temperature or catalyst concentration beyond 3.5% led to a decline in yield, particularly at temperatures exceeding 60°C. This suggests that certain reaction conditions may reverse the transesterification process, pushing the products back toward the reactants and reducing efficiency.