cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
Dr. Basari
Contact Email
basari.st@ui.ac.id
Phone
+6221-29120943
Journal Mail Official
editor_mst@ui.ac.id
Editorial Address
Universitas Indonesia ILRC Building, 1st Floor, Depok 16424, Indonesia Kota depok, Jawa barat INDONESIA
Location
Kota depok,
Jawa barat
INDONESIA
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
 43   44   45   46   47 
Permeability Prediction for Expansive Soil Based on Physical Properties Using Artificial Neural Networks Fatnanta, Ferry; Suprayogi, Imam; Ranata, Nicola Rabb; Nugroho, Soewignjo Agus; Putra, Agus Ika
Makara Journal of Technology Vol. 27, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Permeability is a soil parameter related to the construction industry to understand the processes of infiltration, runoff, and settlement. The risk of testing errors is inevitable in permeability investigations, especially in expansive soils. Trial and error in permeability testing becomes difficult due to soils with small pore sizes and large shrinkage expansion. Several studies related to soil physical properties that affect permeability have been conducted. However, the correlation results obtained still have poor accuracy. Artificial neural networks (ANN) are machine learning systems that can change their structure to solve problems that are included in the system. The use of ANNs in data learning is applied to help the established model predict future output values with a small error value. This research aims to study the correlation between the physical properties of expansive soil that affect its permeability using ANN correlation and then produce correlation equations for future inputs. The research was conducted with input data in the form of soil liquid limit, soil plasticity index (IP), %fine grains, and soil permeability as output data. Results demonstrated a good correlation between soil physical properties and permeability, revealing high accuracy in the output regression equation.
Thermal Performance Investigation of Thermoelectric Cooling System with Various Hot-Side Cooling Methods Prasetyo, Bowo Y; Rosulindo, Parisya P; Wang, Fujen
Makara Journal of Technology Vol. 28, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Thermoelectric devices have been widely used in various applications, including cooling and power generation. The potential application of thermoelectric cooling systems has been studied. However, these systems still face challenges in achieving optimal performance compared with other cooling systems. Several factors, including the hot-side cooling method, influence the performance of thermoelectric systems. This study aimed to investigate the effects of different hot-side cooling methods on the thermoelectric performance and thermal behavior of thermoelectric cooling systems. The testing methods involved the combination of the thermoelectric module with five hot-side heat exchangers, including a square heatsink, a round heatsink, a two-pipe heat pipe, four-pipe heat pipe, and a liquid cooler, with variations in the operating voltage. The experimental results reveal that the different heat exchangers considerably affected the system performance. The liquid cooler consistently achieved the lowest hot- and cold-side temperatures among all heat exchangers. In the case of the ratio of the cooling capacity and temperature difference across the module, the liquid cooler attained the highest values at 12 and 9 V. In addition, the square heatsink exhibited the highest ratio at 6 V. Meanwhile, the coefficient of performance (COP) values were relatively similar in the various heat exchangers, with the liquid cooler generally showing higher COP values.
Hybrid Method Neighbor Node Discovery in Wireless Sensor Networks: A Framework Mekala, Sagar; Kaila, Shahu Chatrapati; Matang, Jyothi Rani
Makara Journal of Technology Vol. 28, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Wireless devices are now being adapted for diverse purposes, such as healthcare, agriculture, transportation, and tactical operations, which present challenges in network formation owing to high device mobility. Current methods rely on discovery techniques for forming wireless sensor networks (WSNs); however, the existing research has been criticized for its high time complexity and redundant neighbor discovery process. In this study, we provide a hybrid strategy to effectively handle the difficulties of locating neighboring nodes in WSNs. Our method combines several strategies to produce precise and effective neighbor detection. Herein, shared memory–based discovery, a beacon technique, and range and distance overlap detection comprise three main phases of the hybrid approach. This approach improves time complexity by ~50% and reduces redundant node discovery by nearly 30%.
Heat Transfer Enhancement in Nanofluid Flows Augmented by Magnetic Flux Arjun, Kozhikkatil Sunil; Kumar, Rakesh
Makara Journal of Technology Vol. 27, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Heat transfer enhancement could be realized using magnetohydrodynamics together with nanofluids specifically in flow micro-convection in a microtube, flow past a vertical porous plate, and square duct flow with discrete heat sources numerically. A critical value for the Rayleigh number, a maximum value for the magnetic field strength, a low Reynolds number, and volume concentrations exists for thermal enhancement to simulate nanofluid flow in a microtube. Heat transfer enhancement is observed with a reduction in the magnetic field strength in a flow past a heated porous vertical plate. Alumina nanofluid subjected to Hartmann number 10 can boost 81% enhancement in Nusselt number in a square duct at lower Reynolds number using three discrete heat sources under the impact of thermal and solutal buoyancy. A 4% increase in the cooling effect near the center of the last heat source in a nanofluid flow is of practical use in hot spot cooling.
Accomplishments of Endwall Contouring on Heat Transfer in a Passage of a Turbine Blade Arjun, Kozhikkatil Sunil; Sunny, Tide Porathoor; Biju, Narayanan
Makara Journal of Technology Vol. 27, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The study explores axisymmetric endwall contouring with emphasis on the design of novel endwalls capable of heat load reduction. Optimizations with parameterization numerically determined by the endwall of flat shape led to the endwall of the contoured shape with substantial depletion of heat transfer in the passage of the vane. Heat transfer attributes for the generated contoured endwalls were analyzed for the exit Reynolds number of 2 × 106 . Endwall three-dimensional contouring resulted in remarkable changes in secondary flow vortices, jet-to-secondary flow interaction, and film cooling effectiveness on the flat endwall. The results pointed out that the axisymmetric convergent contouring causes a significant increase in endwall film cooling, especially for the hard-to-cooled regions throughout the vane, but the level of benefit is significantly affected by the blowing ratios. The obtained efficacy demonstrated the flow impact of the cross-passage on the proliferation of the coolant on top of the flat endwall and the amenability for jet lift-off at elevated blowing ratios. The optimal mass flow rate selection of the current work could identify the passage of the endwall, contoured with superior axial turbine efficiency and durability than that of the flat endwall.
Investigating the Resistance Properties of Concrete Containing Waste Carpet Fibers Nejati, Faezeh; Mahboobi, Ali
Makara Journal of Technology Vol. 27, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This research was conducted with the aim of investigating the use of waste carpet fiber (WCF) and assessing the resistance properties of concrete. The main goal of this study was to investigate the effect of the internal processing of concrete containing WCF on increasing its resistance properties. At the same time, the secondary goals pursued in the research included determining the optimal percentages of carpet fibers in improving compressive strength, tensile strength, and bending strength. The materials used included cement, aggregates, water, WCF, and super lubricant. This research applied seven mixing designs: A, B1, B2, C1, C2, D1, and D2. Mixing plan A was the control plan. Sample B1 contained 2.45 kg/m3 of WCF and 40 kg/m3 of lyca for processing, while sample B2 contained 2.45 kg/m3 of WCF and no lyca. Sample C1 contained 35.7 kg/m3 of WCF and 80 kg/m3 of lyca for processing, sample C2 contained 35.7 kg/m3 of WCF and no lyca, Sample D1 contained 12.25 kg/m3 of WCF and 120 kg/m3 of lyca for processing, and sample D2 contained 12.25 kg/m3 of WCF and no lyca. The results showed that the use of waste carpet fibers and processing by lyca reduced the compressive strength of the samples. The results of the tensile strength test revealed that the use of waste carpet fibers along with processing by lyca increased the tensile strength of the samples. Finally, the flexural strength test results showed that the use of small amounts of WCF and lyca treatment led to an increase in the flexural strength of concrete.
Hydrodynamic Characteristics and Sediment Distribution Patterns in Wulan Delta Estuary, Demak, Indonesia Muskananfola, Max Rudolf; Febrianto, Sigit; Ayuningrum, Diah
Makara Journal of Technology Vol. 27, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Wulan Delta, located in Wedung, Demak, was formed due to the sedimentation process of the Wulan and Serang rivers. Sediment transport starts from rivers to the sea; the process carries nutrients and various chemicals derived from agricultural, industrial, or household activities. This study aims to analyze the characteristics of hydrodynamics, suspended sediment, and bottom sediments in the Wulan Delta waters, Demak. Field data were collected in transitional season two (October) 2022. The obtained data were then analyzed in the laboratory at the Faculty of Fisheries and Marine Science. Results showed that the speed of the surface current in the study area ranged from 0 to 0.1 m/s in spring tide conditions with a surface current pattern coming from the direction of Semarang toward Jepara and 0–0.18 m/s in neap tide conditions with a current pattern coming from the direction of Jepara toward Semarang. The Wulan Delta has a sedimentary characteristic dominated by fine silt, which is as much as 82%–98%, with a deposition characteristic dominated by wave energy that causes successful sediment sorting with a sorting index of −2.25 to 2 and strongly asymmetrical to a small size with a skewness curve value of two.
Ultrasound Application for Oil Extraction of Lemongrass Parts Yuniarto, Kurniawan, Mr; Welt, Bruce Ari, Prof; Muvianto, Cahyo Mustiko Okta, Dr; Muiz, Abdul, Mr
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Power ultrasound creates acoustic cavitation bubbles that encourage shears within food substances. Applying ultrasound improves solvent diffusion into the matrix plant cellular and hence breaks down bioactive substances. This research aims to extract lemongrass oil using ultrasound-assisted extraction (UAE). The essential oil was extracted from different lemongrass parts, such as corm, stalk, and leaf. Then, a 37 kHz UAE was applied below the solvent vapor pressure temperature under different periods, i.e., 15, 30, and 60 min. The solvent temperature logarithmically increased from 28 ℃ to 53 ℃ during 20 min of the ultrasound treatment. Acoustic power was obtained from a graphic plot by approximately 35.68 kJ for the initial 20 min and by 31.14 kJ for the remaining UAE period. The lemongrass oil obtained a higher yield from the corm section about 3 and 1.4 times compared to stalk and leaf components. The extracted lemongrass oil produced a yellowish color from the leaf and stalk and a yellow-red color from the corm. The refractive index varied between 1.389 and 1.422, and the specific gravity was from 0.89 to 0.97 g/cm3 . The lemongrass leaf produced the highest citral content and more saturated lipid acids than unsaturated in the lemongrass essential oil.
Utilization of Biopertalite for Fuel Efficiency and Reduction in CO and CO2 Gas Emissions in Four-Wheel Motor Vehicles Iskandar, Ridwan; Hadiyanto, Hadiyanto; Suherman, Suherman; Zakaria, Zainul Akmar
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Emissions of carbon monoxide (CO) and carbon dioxide (CO2) gases are the main problem that must be rectified as they are harmful and contribute to global warming through the greenhouse gas effect. In Indonesia, motor vehicles, especially four wheelers, are one of the biggest contributors with up to 71 million tons of CO2 emissions and energy consumption of 179 million barrel of oil equivalent. Bioethanol has octane rating >100, which is higher than that of gasoline; and emission contribution of only 0.02 kg/L, which is lower than that from gasoline (2.23 kg/L). Accordingly, a mixture of gasoline and bioethanol is the solution proposed in this study to solve the issues of CO and CO2 emissions. Gasoline and bioethanol mixture consists of six products, namely E-0, E-5, E-10, E-15, E-20, and E-25, which have different percentage values of bioethanol mixture (0%–25%). This study was conducted through engine testing with different rpm values (500–2500 rpm) to identify the concentration and mass of CO2 emissions, fuel efficiency, and cost efficiency. Based on the test results, this product succeeded in reducing CO emissions by up to 86% and CO2 emissions up to 30.6% from Pertalite (E-0) and increasing the fuel efficiency up to 51.76% for 1 L and cost efficiency up to 33.6% after considering the actual price of Pertalite. Therefore, the proposed product can be a solution to the existing problems.
Removal of Hexavalent Chromium from Water by Chitosan-Enhanced Ultrafiltration Indiasih, Putu A. Y.; Syaifudin, Anindita D.; Himma, Nurul Faiqotul; Ismuyanto, Bambang
Makara Journal of Technology Vol. 27, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Polymer-enhanced ultrafiltration has gained increasing attention as a selective separation process to remove small solutes, such as metal ions, from water or wastewater. Hexavalent chromium Cr(VI) is one of the metal ions in wastewater that has received considerable attention because of its toxicity. Chitosan was used in this study as the polymer to bind Cr(VI) to enhance its removal by ultrafiltration. The effects of chitosan-to-Cr(VI) ratio on Cr(VI) rejection and permeate flux were investigated. In addition, the fouling tendency was evaluated. Results showed that the addition of chitosan with a mass ratio of 12.5 increased the Cr (VI) rejection from 28% to 75% with a slight reduction in permeate flux from 12.5 L.m−2.h−1 to 9.3 L.m−2.h−1. Moreover, the reduced flux after 100 min of operation could be recovered using the backwash procedure by 89% compared to the initial flux.

Page 45 of 49 | Total Record : 485

 43   44   45   46   47 

Filter by Year

2002 2025


Reset
Filter By Issues
All Issue Vol. 29, No. 2 Vol. 29, No. 1 Vol. 28, No. 3 Vol. 28, No. 2 Vol. 28, No. 1 Vol. 27, No. 3 Vol. 27, No. 2 Vol. 27, No. 1 Vol. 26, No. 3 Vol. 26, No. 2 Vol. 26, No. 1 Vol. 25, No. 3 Vol. 25, No. 2 Vol. 25, No. 1 Vol. 24, No. 3 Vol. 24, No. 2 Vol. 24, No. 1 Vol. 23, No. 3 Vol. 23, No. 2 Vol. 23, No. 1 Vol. 22, No. 3 Vol. 22, No. 2 Vol. 22, No. 1 Vol. 21, No. 3 Vol. 21, No. 2 Vol. 21, No. 1 Vol. 20, No. 3 Vol. 20, No. 2 Vol. 20, No. 1 Vol. 19, No. 3 Vol. 19, No. 2 Vol. 19, No. 1 Vol. 18, No. 3 Vol. 18, No. 2 Vol. 18, No. 1 Vol. 17, No. 3 Vol. 17, No. 2 Vol. 17, No. 1 Vol. 16, No. 2 Vol. 16, No. 1 Vol. 15, No. 2 Vol. 15, No. 1 Vol. 14, No. 2 Vol. 14, No. 1 Vol. 13, No. 2 Vol. 13, No. 1 Vol. 12, No. 2 Vol. 12, No. 1 Vol. 11, No. 2 Vol. 11, No. 1 Vol. 10, No. 2 Vol. 10, No. 1 Vol. 9, No. 2 Vol. 9, No. 1 Vol. 8, No. 3 Vol. 8, No. 2 Vol. 8, No. 1 Vol. 7, No. 3 Vol. 7, No. 2 Vol. 7, No. 1 Vol. 6, No. 3 Vol. 6, No. 2 Vol. 6, No. 1 More Issue