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Makara Journal of Technology
Published by Universitas Indonesia
ISSN : 23552786     EISSN : 23564539     DOI : https://doi.org/10.7454/mjt
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Materials Science & Nanotechnology Mechanical Engineering
MAKARA Journal of Technology is a peer-reviewed multidisciplinary journal committed to the advancement of scholarly knowledge and research findings of the several branches of Engineering and Technology. The Journal publishes new results, original articles, reviews, and research notes whose content and approach are of interest to a wide range of scholars. It also offers rapid dissemination. MAKARA Journal of Technology covers the recent research in several branches of engineering and technology include Electrical & Electronics Engineering, Computer Engineering, Mechanical Engineering, Chemical & Bioprocess Engineering, Material & Metallurgical Engineering, Industrial Engineering, Civil & Architecture Engineering, and Marine Engineering. Criteria used in determining acceptability of contributions include newsworthiness to a substantial part of the engineering & technology and the effect of rapid publication on the research of others. This journal, published three times each year, is where readers look for the advancement of discoveries in engineering and technology.
Arjuna Subject : Teknik (semua kategori) - Teknik (Lain-Lain)
Articles 485 Documents
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Computational Fluid Dynamics (CFD) Modeling for Bio-Inspired Aerodynamic Optimization in Autonomous Drones Unegbu, Hyginus C.O.; Yawas, Danjuma Saleh
Makara Journal of Technology Vol. 29, No. 2
Publisher : UI Scholars Hub

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Abstract

This study explores the aerodynamic benefits of bio-inspired design modifications for autonomous drones using advanced Computational Fluid Dynamics (CFD) simulations. Four bio-inspired configurations—leading-edge serrations, winglets, riblet surfaces, and curved wings—were assessed and compared against a baseline drone model to evaluate their impact on aerodynamic performance. The results indicated that all bio-inspired designs significantly enhanced lift, reduced drag, and improved overall aerodynamic efficiency. The leading-edge serration configuration achieved the highest performance gains, with a 33.6% increase in maximum lift coefficient (CL) and a 29.5% improvement in lift-to-drag ratio (CL/CD), primarily due to delayed flow separation and reduced turbulence. Winglets minimized wingtip vortices, leading to an 18.3% reduction in drag coefficient (CD) and improved lift efficiency. Riblet surfaces moderately decreased drag by streamlining boundary layer flow, while the curved wing design enhanced stability and manoeuvrability at high angles of incidence. These findings demonstrate the potential of bio-inspired designs to optimize drone performance, extending their operational range and adaptability across varying flight conditions. The study provides valuable insights for development of next-generation UAVs, offering a pathway to improved energy efficiency, flight stability, and versatility in diverse operational environments.
Assessing Solar Radiation Patterns in Sarawak using Measured Data and the Hargreaves-Samani Model for Photovoltaic Systems Application Soo, Chun Yong; Chan, Xian Hwa; Wan Mokhtar, Wan Mohamad Husni; Mohd Rais, Ahmad Rujhan
Makara Journal of Technology Vol. 29, No. 2
Publisher : UI Scholars Hub

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Abstract

This study evaluates the Hargreaves-Samani model for estimating solar radiation in five locations in Sarawak: Bintulu, Kapit, Sri Aman, Kuching, and Miri (Subis), using minimum and maximum temperatures as key inputs. Analysis reveals stable minimum temperatures (19.7 °C to 28.8 °C), supporting consistent solar radiation patterns favorable for Photovoltaic (PV) performance. Miri (Subis) recorded the highest daily maximum temperature of 44.8 °C, while Kuching had the lowest at 24.7 °C, highlighting significant regional climatic variability. Analysis also indicates strong solar potential in Bintulu, Kapit, Sri Aman, Kuching, and Miri, with radiation peaking at 7.5 kWh/m², though seasonal variations impact PV power generation. Initial solar radiation, RI estimates range from 2.49 to 7.81 kWh/m² annually, demonstrating substantial seasonal and regional differences. Re-optimized adjustment coefficients (k) indicate that Bintulu (0.190) and Kuching (0.186) exceed coastal standards (0.16), while Kapit (0.168), Sri Aman (0.175), and Miri (0.160) are below inland standards (0.19). These adjustments yield optimized solar radiation, RO values ranging from 2.15 to 7.351 kWh/m², confirming significant PV potential. Cloud cover varies from 20.3% to 100%, peaking during monsoon seasons and decreasing in drier months. The Hargreaves-Samani model demonstrated the highest accuracy in Sri Aman (RMSE: 29.63%) and Kapit (RMSE: 32.76%), with lower accuracy in Bintulu (RMSE: 59.34%) when comparing measured and optimized solar radiation. These findings provide valuable insights for enhancing solar energy utilization and optimizing PV systems in Sarawak’s tropical climate.
Direct Control Strategy using Polynomial Fuzzy-Based Adaptive Fractional Order PID Controller Rospawan, Ali; Angelina, Clara Lavita; Samsuri, Faisal; Baihaqi, Muhammad Yeza; Halawa, Edmun; Munajat, Muhammad; Vincent, Vincent; Setiyadi, Surawan; Purnama, Irwan; Simatupang, Joni Welman
Makara Journal of Technology Vol. 29, No. 2
Publisher : UI Scholars Hub

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Abstract

This paper presents a novel direct control strategy using a polynomial fuzzy neural network-based adaptive fractional order proportional integral derivative (PFNN-AFOPID) controller for nonlinear and time-varying systems. The proposed approach integrates the enhanced flexibility of fractional order calculus PID with the superior nonlinear approximation capabilities of polynomial fuzzy models, enabling dynamic adjustment of all control parameters without requiring precise mathematical modeling of system dynamics. By extending traditional PID control with fractional-order operations, the controller achieves improved frequency response and robustness against disturbances. Experimental validation on a DC motor position control system demonstrates significant performance improvements. Compared to traditional PID, the proposed PFNN-AFOPID achieved a performance improvement of 53.69% in RMSE, 78.56% in ISE, 69.92% in IAE, and 83.98% in ITAE. When compared to the existing fuzzy neural network-based adaptive PID (FNN-APID), our approach delivered improvements of 21.06% in RMSE, 28.79% in ISE, 5.69% in IAE, and 32.86% in ITAE. These results confirm the superior capability of the proposed approach in handling system nonlinearities while maintaining precise control under varying operational conditions, without requiring prior system dynamics knowledge or extensive offline training.
Effect of Contact Time and Concentration on Adsorption of Pb2+Metal Ion Utilizing Crab Shell Chitosan and Activated Bentonite Clay Composite Sasria, Nia; Wisaka, Adi; Yusariarta Putra Parmita, Ade Wahyu; Nur Tajalla, Gusti Umindya
Makara Journal of Technology Vol. 29, No. 2
Publisher : UI Scholars Hub

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Abstract

Indonesia produced 1,508 tons of nonliving crabs in the January–March 2020 period. The number of shells generated can account for 40%–60% of the overall weight. Therefore, using crab shells made into chitosan is expected to increase the economic value and reduce waste from crab shells. Chitosan can be modified with clay previously activated with an acid solution to form a chitosan–clay composite to improve the adsorption capacity. This study aims to analyze the differences in characteristics between chitosan and clay before and after the immobilization process. A comparison of chitosan and clay (1:2) is conducted on the basis of variations in the contact time for 5, 30, 55, and 80 min and in the concentration of metal solution as much as 10, 30, and 50 ppm. The results of the Fourier transform infrared spectroscopy (FTIR) study found stretching vibrations of –NH originating from the chitosan structure, as well as several functional groups from clay, such as silanol (Si–OH) and siloxane (Si–O–Si). The results of the X-ray diffraction (XRD) test show that the clay used was bentonite clay. Meanwhile, the scanning electron microscopy (SEM) and surface area analyzer (SAA) test results show that the chitosan–clay adsorbent has a rougher and hollower surface with a surface area of 23,666 m2/g. The best adsorption percentage of 90.59% occurred at a concentration of 10 ppm with a contact time of 30 min.
Determination of Excess Pore Pressure in Under Consolidating Soil by using CPTu Ihut, Karolina Villa Delfia; Wijaya, Martin; Lim, Aswin; Satyanaga, Alfrendo; Aglia, Grisella; Syifanaya, Sharfina Faradiba; Sugianto, Andy
Makara Journal of Technology Vol. 29, No. 2
Publisher : UI Scholars Hub

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Abstract

North Jakarta is predominantly composed of soft soil that is still undergoing consolidation. According to research by Raharjo et al. (2022), excess pore pressure is still present in the soils of Jakarta. The degree of consolidation and excess pore pressure values indicate that consolidation is not yet complete (Raharjo et al., 2022). In this study, the researchers developed two methods to determine excess pore pressure using field testing. The Stress History and Normalized Soil Engineering Properties (SHANSEP) model equation from Ladd and Foot (1974), as well as Finite Element Method (FEM) modeling using the PLAXIS program, were utilized to estimate the excess pore pressure in the soil. The results from the SHANSEP-based analysis were then compared with those from the FEM analysis using PLAXIS. The comparison showed that the excess pore pressure estimated using PLAXIS closely matched the values obtained from CPTu tests based on the SHANSEP model. Interpretation of parameters from the Cone Penetration Test with pore pressure measurement (CPTu) indicates that the soil at the project site is still consolidating and undergoing settlement. Similarly, the settlement results from the PLAXIS analysis support this conclusion.

Page 49 of 49 | Total Record : 485

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