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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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Briquette of Empty Fruit Bunch Fiber as an Alternative Substitution for Binderless Fuel Methods Handra, Nofriady; Indra, Ade
Makara Journal of Technology Vol. 27, No. 3
Publisher : UI Scholars Hub

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Abstract

Biomass development has been a key issue for the past few decades and will remain attractive in the future because of its cleanliness, renewability, carbon neutrality, and other advantages. This study aims to determine the optimal holding time for heating system briquettes by testing the heating value of empty fruit bunches fibers. The process of this research involves the use of one unit of briquette molding equipment by providing a heating system to the mold cylinder. Fibers were manually finetuned until they reached a size of 20 mesh (0.84 mm). Densification temperature is an essential factor that could affect the combustion properties, especially the calorific value. The Arduino program is used for setting the heating resistance time of the mold, which is 15, 20, and 25 min at a temperature of 200 ºC, and the thermal controller is used to adjust the temperature variation. Results showed that the highest calorific value of the three varieties of holding time was at 25 min with a calorific value of 4480.2 cal/g, and the lowest cost at 15 min was 4022 cal/g. Meanwhile, a calorific value of 4432.5 cal/g was found at 20 min. This finding is due to the low moisture content and high charcoal content of the sample in the 25 min briquette mold. Therefore, briquettes at 25 min have a higher heating value compared with those at 15 and 20 min holding time.
Supermarket and Water Spider Concept for Improving Door Sub-Assembly Productivity Barnas, Andreas; Pratama, Aditya T.; Awibowo, Setijo
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

This research is based on a case study at the door sub-assembly area of a German car manufacturer in Indonesia. The door sub-assembly area is responsible for assembling doors to be supplied to the specific station in assembly line that will assemble the finished doors to the car. The area had a problem in supplying the doors to the main assembly line on time. This means, the cycle time of door sub-assembly is higher than that of the assembly line. After observation, the factor that greatly contributes to the high cycle time can be identified, which is motion waste. Therefore, a unique approach is offered to overcome the situation, which involves re-designing work system and work area. The approach is to implement new working system by adopting lean tool water spider to significantly reduce motion waste. In the end, the initial and after condition will be contrasted to see the improvement made by this research. The results of this study could give the company several benefits: improved working efficiency of workers, reduced cycle time in door assembly and reduced fatigue of workers.
Challenges in Optimization for the Performance on Sustainability Dimensions in Reverse Logistics Social Responsibility Sudarto, Sumarsono; Takahashi, Katsuhiko; Dewo, Mochammad
Makara Journal of Technology Vol. 27, No. 2
Publisher : UI Scholars Hub

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Abstract

Reverse logistics social responsibility is preferred as the most acceptable solution for addressing the challenges in stakeholders’ debate regarding social responsibility in supply chains because it involves as many actors as possible in the supply chain to perform social responsibility to achieve sustainability. This paper explores the challenges in achieving optimal policies in sustainability dimensions for collection and recycling facilities in reverse logistics. Sustainability dimensions include economic, environmental, and social aspects. The reverse logistics is modeled on System Dynamics, and a simplified statistical analysis using a contour chart is employed in numerical experiments. Results show a narrow area of optimal solutions in contour charts for policy parameter settings to realize sustainability. Therefore, this paper finds that optimization of reverse logistics to develop sustainability is a highly challenging task for policy makers. Therefore, managers must carefully study their policies before implementation to avoid unnecessary and less optimal performance in the sustainability dimensions.
Damage Stability Study of A 500 DW Ro-Ro Ferry Vessel Ariany, Zulfaidah; Santoso, Budhi; Sarwoko, Sarwoko; Prasetyo, Nauval Abdurrahman
Makara Journal of Technology Vol. 26, No. 3
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Abstract

The development of the crossing transportation industry is currently increasing in the island areas. The use of Ro-Ro type ferry boats is extremely efficient in moving people, goods, and vehicles. The current research focuses on the damage stability of the 500 DWT Ro-Ro ferry, which aims to meet the needs of the Ro-Ro ferry in the archipelago area. The previously existing initial design of a barge hull with a main size Lpp = 40.15 m, B = 12 m, H = 3.2 m, and T = 2.15 m was used to analyze the damage stability condition further. First, the drawings were redrawn. Then, 3D modeling was performed and the tanks were inspected. The processing of the input data design was finally tested under several criteria based on damage stability in SOLAS 2009. This study concluded whether the 500 DWT Ro-Ro ferry design is acceptable considering damage stability. The GZ value is standardized in the scenario of calcge stability of the Ro-Ro ferry as a whole. Attention should be provided to the range of positive stability in intermediate stages considering the forward damage case, wherein the ship departs and the full load experiences failure.
Optimization of the Building Envelope and Roof Shading to Reduce the Energy Consumption of College Low-Rise Buildings in Indonesia Nasruddin, Nasruddin; Alam, Azimil Gani; Sohel, Mohammad Imroz
Makara Journal of Technology Vol. 27, No. 3
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Abstract

Energy consumption in buildings is a crucial concern globally, prompting researchers to explore innovative solutions to mitigate its impact. This study investigates the optimization of building envelopes and roof shading systems of existing buildings in Indonesia to realize notable energy savings. Multiple scenarios were explored, with modifications to building envelopes and roof shading, highlighting the overall thermal transfer value as a key parameter. Using EnergyPlus simulations, the efficacy of natural ventilation in corridors and roof shading modifications was assessed in reducing energy consumption. The findings revealed that renovating existing buildings by optimization of the building envelope and roof shading by simulations can contribute considerably to energy conservation. Various scenarios produced distinct energy savings, underscoring the importance of empirically planned modifications. Substantial reductions in energy and even water consumption were realized by applying natural ventilation in corridors and modifying roof shading, demonstrating a promising approach. Furthermore, avenues for future research were discussed, pointing toward the need for comprehensive analyses of diverse building types, climates, and geographical locations. This study can serve as foundational step toward developing practical guidelines for energy-saving retrofits in existing buildings in Indonesia and similar climate.
Endwall Contouring for Lowering the Thermal Load and Augmenting the Turbine Efficiency Sunil, Arjun Kozhikkatil; Sunny, Tide Porathoor
Makara Journal of Technology Vol. 28, No. 2
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Abstract

Endwall contouring having significance in delineating ideal endwalls competent in thermal load depletion is the focus of this study. We have successfully utilized non-axisymmetric contoured endwalls to enhance turbine performance by controlling the secondary flow characteristics in a blade passage through steady-state numerical hydrodynamics. The supreme endwall pattern could lower the gross pressure loss at the design stage and is related to the size of the top-loss location being productively lowered. The selective numerical shape change using multi-objective optimization at the most prominent locations resulted in contoured endwall geometry and a considerable reduction of thermal exchange in the vane passage and thermal load in the turbines. A non-axisymmetric contoured endwall achieves the highest net heat flux reduction and elevated aerodynamic performance with lower total pressure loss coefficients than an axisymmetric convergent contoured endwall at most locations of the endwall. In the present study, the ideal mass flow rate could pinpoint the endwall passage, contoured with outstanding axial turbine competence and longevity. Endwall contouring enhances turbine performance, and augmented efficiency is achieved with optimized shapes.
Optimization of Bioethanol Production Using an Enzymatic Hydrolysis Process with Green Algae (Chaetomorpha) as the Raw Material Maimun, Teuku; Lubis, Mirna Rahmah; Zein, Muhammad Aldi; Ali, Wahed Febbry Andriansyah
Makara Journal of Technology Vol. 28, No. 2
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Abstract

Bioethanol is an alternative fuel derived from biological feedstock used to decrease the reliance on fossil fuels because of increasing energy consumption associated with population growth and increased use of oil fuels. Bioethanol production has been widely conducted using several types of algae, but the optimal conditions for the hydrolysis and fermentation processes are not explained in more detail. Therefore, this study focuses on determining the optimal conditions for hydrolysis and fermentation to maximize the bioethanol yield. This study uses optimization based on the hydrolysis time, temperature, and pH to increase the reducing sugar content using high-performance liquid chromatography in the enzymatic hydrolysis process. The process consists of liquefaction and saccharification steps, where 4% α-amylase enzyme and 2%, 3%, and 4% glucoamylase are used. Results showed that the optimal conditions for the hydrolysis time were 180 min at temperatures of 70 °C to 80 °C. The enzymatic hydrolysis process is conducted under optimal conditions, followed by the fermentation process. Finally, the distillation process was performed with a maximum bioethanol yield of 25.0%.
Effect of Tibial Malrotation on Anterior and Posterior Cruciate Ligaments in Bicruciate-Retaining Total Knee Arthroplasty Sa’audi, Muhammad Saakeereen; Abdullah, Abdul Halim; Shuib, Solehuddin; Mat Raffei, Muhammad Azim; Mohd Miswan, Mohd Fairudz; Mohd Anuar, Mohd Afzan
Makara Journal of Technology Vol. 28, No. 2
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Abstract

Osteoarthritis (OA) is a musculoskeletal disorder specified as a joint disease that affects mostly human joints worldwide. Total knee arthroplasty (TKA) is performed to restore the affected joint and relieve the symptoms. However, tibial malrotation, which is one of the most common errors in TKA, results in poor function of the implant and pain after the procedure. People with OA often experience limited mobility and cannot accomplish daily tasks. Finite element analysis (FEA) has been widely applied to interpret the biomechanical and kinematic force along the joint and investigate the cruciate ligament’s mechanical behavior. Unfortunately, one of the problems in TKA implants is their malalignment affecting tibial rotation. This study employs FEA to investigate the relationship between tibial malrotation and the consequent displacements and forces in the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). A subject-specific knee model is used to study the effects of ligament model complexity and simulated ligament wrapping on knee biomechanics and kinematics. Tibial malrotation had a more considerable effect on ACL than on PCL. In terms of ligament forces, both anterior and posterior PCL bundles generated notably greater forces compared with the ACL bundles, with averages of 26823.92 ± 13.32 N and 2796.49 ± 23.98 N, respectively. The displacement of the PCL bundles was also substantial, equaling 26.37 ± 0.01 mm in the anterior and 18.87 ± 0.08 mm in the posterior. Correct implant alignment is essential to avoid overtensioning of the ligament and offers knee joint ligament balance that can restore native knee kinematics.
Modeling Soil Lateral Deformation Due to Water Film using Smoothed Particle Hydrodynamics Bahsan, Erly; Soepandji, Budi Susilo; Rahayu, Wiwik; Marthanty, R.R. Dwinanti R.; Ontowirjo, Budianto
Makara Journal of Technology Vol. 28, No. 2
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Abstract

In geotechnical engineering, large deformation in soil materials is rarely simulated using numerical methods, particularly the finite element method and finite difference method, because they experience difficulties in representing the postfailure soil behavior. As an alternative to these methods, the smoothed particle hydrodynamics (SPH) method has recently been adopted to represent soil behavior. The SPH method is a Lagrangian, mesh-free numerical method in which the materials are modeled as a set of particles. In this method, soil behavior can be represented via the Drucker–Prager elasto–plastic failure criterion. Thus, this method can be used to simulate postfailure soil behavior and large deformation in soil materials. This study attempts to analyze large deformation of soil due to an extremely gentle slope and a thin water layer (referred to as the water film). The model is simulated using a C++ platform called PersianSPH. The results demonstrate that lateral deformation can occur in such a geometry because of the effective stress changes during liquefaction.
Thermomechanical Analysis of Biomass Plastic Composite (BPC) Madu, Solomon Chijioke; Aigbodion, Victor Sunday; Ike-eze, Ikechukwu
Makara Journal of Technology Vol. 28, No. 2
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Abstract

High-performance electrical insulation material can be manufactured using biomass plastic composite (BPC), which is a new type of composite material that is either made up of one or a combination of natural plant fibers/particulates, such as bamboo, cellulose fiber, rice husks, or hemp, and thermoplastic granules. In this study, the BPC composite material that was developed comprised polyethylene (PE), rice husk, and oyster shell. The results of the study showed a significant optimal improvement in the morphological, thermodynamic, and mechanical properties during the addition of 20% to 30% biomass particulates (i.e., rice husk and oyster shell). The thermogravimetric analysis, storage modulus, loss modulus, and damping factor (also known as the tangent of delta [tanδ]) values showed that compositions of the BPC material exhibited an increasing optimal thermomechanical stability when the composition of the BPC material was made with an increasing mixture of oyster shell, rice husk, and PE compared with that when only rice husk was added to PE. Similarly, the mechanical property of BPC was enhanced with 30% biomass material (i.e., rice husk and oyster shell) and 70% low-density PE plastics. This result indicated that BPC materials can be highly durable and long-lasting, as they are less prone to cracking or breaking.

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