Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Journal

Makara Journal of Technology

Discipline
Keyword
Publication Year

Articles 1 - 30 of 447

Full-Text Articles in Engineering

Briquette Of Empty Fruit Bunch Fiber As An Alternative Substitution For Binderless Fuel Methods, Nofriady Handra, Ade Indra Dec 2023

Briquette Of Empty Fruit Bunch Fiber As An Alternative Substitution For Binderless Fuel Methods, Nofriady Handra, Ade Indra

Makara Journal of Technology

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 …


Heat Transfer Enhancement In Nanofluid Flows Augmented By Magnetic Flux, Kozhikkatil Sunil Arjun, Rakesh Kumar Dec 2023

Heat Transfer Enhancement In Nanofluid Flows Augmented By Magnetic Flux, Kozhikkatil Sunil Arjun, Rakesh Kumar

Makara Journal of Technology

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 …


Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras Dec 2023

Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras

Makara Journal of Technology

Decaffeination by microbial degradation is currently the most optimal and low-cost approach, involving only microbial cells and/or their enzymes. The bacterium was characterized using a series of biochemical tests. Positive results were obtained from carbohydrate fermentation, citrate utilization, and catalase tests, while negative results were obtained from Voges-Proskauer (VP) and indole tests. Three different caffeine concentrations of 0.25%, 0.4%, and 2% were tested and measured through Gas Chromatography-Mass Spectrophotometry (GC-MS) analysis. The highest caffeine reduction (89.25%) was found when 0.25% caffeine was used in the media. Only a small amount of caffeine was reduced to 0.4% and 2%, with 34.78% …


Effect Of Lime Content, Curing Temperature, And Aging Condition On Low-Alkaline Concrete, Mahdi Parsa Pour, Reza Shaban Sharghi, Faezeh Nejati, Elmira Khaksar Najafi Dec 2023

Effect Of Lime Content, Curing Temperature, And Aging Condition On Low-Alkaline Concrete, Mahdi Parsa Pour, Reza Shaban Sharghi, Faezeh Nejati, Elmira Khaksar Najafi

Makara Journal of Technology

This study determines how curing temperatures, aging condition, and hydrated lime contents affect the unconfined compressive strength (UCS), modulus of elasticity, and workability of low-alkaline concrete. Samples were prepared in two different groups to determine the optimum hydrated lime content and aging conditions to assess the mutual effect of NaOH molarity and curing temperature, that is, 70 °C for 48 h or room temperature, on samples with and without lime. The results showed that the increase in hydrated lime content affected alkali concentration. The samples with lime exhibited a clear peak in UCS (6 M NaOH) compared with the continuous …


Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel Dec 2023

Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel

Makara Journal of Technology

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 …


Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo Aug 2023

Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo

Makara Journal of Technology

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 …


Investigating The Resistance Properties Of Concrete Containing Waste Carpet Fibers, Faezeh Nejati, Ali Mahboobi Aug 2023

Investigating The Resistance Properties Of Concrete Containing Waste Carpet Fibers, Faezeh Nejati, Ali Mahboobi

Makara Journal of Technology

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. …


Permeability Prediction For Expansive Soil Based On Physical Properties Using Artificial Neural Networks, Ferry Fatnanta, Imam Suprayogi, Nicola Rabb Ranata, Soewignjo Agus Nugroho, Agus Ika Putra Aug 2023

Permeability Prediction For Expansive Soil Based On Physical Properties Using Artificial Neural Networks, Ferry Fatnanta, Imam Suprayogi, Nicola Rabb Ranata, Soewignjo Agus Nugroho, Agus Ika Putra

Makara Journal of Technology

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 …


Accomplishments Of Endwall Contouring On Heat Transfer In A Passage Of A Turbine Blade, Kozhikkatil Sunil Arjun, Tide Porathoor Sunny, Narayanan Biju Aug 2023

Accomplishments Of Endwall Contouring On Heat Transfer In A Passage Of A Turbine Blade, Kozhikkatil Sunil Arjun, Tide Porathoor Sunny, Narayanan Biju

Makara Journal of Technology

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 …


The Relaying Network In Free-Space Optical Communications Using Optical Amplifiers In Cascaded Configuration, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo Aug 2023

The Relaying Network In Free-Space Optical Communications Using Optical Amplifiers In Cascaded Configuration, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo

Makara Journal of Technology

Optical relaying is the best technique to implement free-space optical (FSO) communications as a terrestrial platform. However, atmospheric turbulence (AT) limits the optical-propagation path length. In this study, the implementation of some optical amplifiers (OAs) in cascaded configuration, namely, erbium-doped fiber amplifiers, semiconductor OAs, and Raman amplifiers (RAs), are investigated through simulation. This study aims to search for the maximum link distance of an optical propagation and enhance the FSO performance caused by each configuration of OAs. The optical relaying network consists of three nodes, with each node designed with a space of several kilometers under the influence of AT. …


Restorative Hand Therapy Exercise Using Iot-Based Flex Force Smart Glove, Yi Neng Chang, Mohamad Khairi Ishak, Khalid Ammar Apr 2023

Restorative Hand Therapy Exercise Using Iot-Based Flex Force Smart Glove, Yi Neng Chang, Mohamad Khairi Ishak, Khalid Ammar

Makara Journal of Technology

Stroke has long been a major health concern in Malaysia, with cerebrovascular disease accounting for one-third of all deaths. Patients who have had a stroke have varying degrees of movement impairment, which can be improved with physiotherapy. A smart glove system is proposed in this paper to measure and visualize patient finger flexes in real-time remotely and record these flexes for further analysis to monitor and assess patient physiotherapy sessions. The system is designed to help physiotherapists evaluate physiotherapy exercises of patients and provide detailed information regarding the rehabilitation process. This paper also includes performance analysis and data from physiotherapy …


Removal Of Hexavalent Chromium From Water By Chitosan-Enhanced Ultrafiltration, Putu A. Y. Indiasih, Anindita D. Syaifudin, Nurul Faiqotul Himma, Bambang Ismuyanto Apr 2023

Removal Of Hexavalent Chromium From Water By Chitosan-Enhanced Ultrafiltration, Putu A. Y. Indiasih, Anindita D. Syaifudin, Nurul Faiqotul Himma, Bambang Ismuyanto

Makara Journal of Technology

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 …


User Classification Based On Mouse Dynamic Authentication Using K-Nearest Neighbor, Didih Rizki Chandranegara, Anzilludin Ashari, Zamah Sari, Hardianto Wibowo, Wildan Suharso Apr 2023

User Classification Based On Mouse Dynamic Authentication Using K-Nearest Neighbor, Didih Rizki Chandranegara, Anzilludin Ashari, Zamah Sari, Hardianto Wibowo, Wildan Suharso

Makara Journal of Technology

Mouse dynamics authentication is a method for identifying a person by analyzing the unique pattern or rhythm of their mouse movement. Owing to its distinctive properties, such mouse movements can be used as the basis for security. The development of technology is followed by the urge to keep private data safe from hackers. Therefore, increasing the accuracy of user classification and reducing the false acceptance rate (FAR) are necessary to improve data security. In this study, we propose to combine the K-nearest neighbor method and simple random sampling and obtain a sample from a dataset to improve the classification of …


Performance Of A Solar Seawater Distillation With A Triangle Prism Cover And A Fin-Type Absorber, Risse Entikaria Rachmanita, Miftah Khoirul Umam Apr 2023

Performance Of A Solar Seawater Distillation With A Triangle Prism Cover And A Fin-Type Absorber, Risse Entikaria Rachmanita, Miftah Khoirul Umam

Makara Journal of Technology

Solar-powered distillation is a seawater distillation method that utilizes solar heat as its main energy source for the purpose producing freshwater and a by-product of the distillation process in the form of salt. This study aims to determine the performance of a solar seawater distillation design with a semi-batch system by combining a fin-type absorber plate and a triangular prism cover. This design is equipped with a reflector and absorber plate, which has a surface area of 0.3969 m2 with a volume capacity of seawater that can be accommodated in a basin of ±24 liters. It uses a knockdown system …


Supermarket And Water Spider Concept For Improving Door Sub-Assembly Productivity, Andreas Barnas, Aditya T. Pratama, Setijo Awibowo Dec 2022

Supermarket And Water Spider Concept For Improving Door Sub-Assembly Productivity, Andreas Barnas, Aditya T. Pratama, Setijo Awibowo

Makara Journal of Technology

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, …


Utilization Of Biopertalite For Fuel Efficiency And Reduction In Co And Co2 Gas Emissions In Four-Wheel Motor Vehicles, Ridwan Iskandar, Hadiyanto Hadiyanto, Suherman Suherman, Zainul Akmar Zakaria Dec 2022

Utilization Of Biopertalite For Fuel Efficiency And Reduction In Co And Co2 Gas Emissions In Four-Wheel Motor Vehicles, Ridwan Iskandar, Hadiyanto Hadiyanto, Suherman Suherman, Zainul Akmar Zakaria

Makara Journal of Technology

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 …


Design And Prototyping Of A Low-Cost High Frequency Antenna For Vicinity Coupling Devices, Benjamin Kommey, Ernest Ofosu Addo, Elvis Tamakloe Dec 2022

Design And Prototyping Of A Low-Cost High Frequency Antenna For Vicinity Coupling Devices, Benjamin Kommey, Ernest Ofosu Addo, Elvis Tamakloe

Makara Journal of Technology

This paper describes the development of a high frequency (HF) antenna for high output power vicinity coupling devices (VCDs) operating at 13.56 MHz. Key design parameters, such as RF power level, antenna size, and communication protocol, and their link to the antenna features and requirements, have been discussed. For efficient reader interrogation, detection, and recovery of transponder responses, a tuning circuit necessary to adjust the antenna power matching and resonance characteristics was designed and prototyped. The antenna was fed to an industry standard reader and evaluated for read range performance with vicinity cards. The designed antenna on the reader achieved …


Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo Dec 2022

Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo

Makara Journal of Technology

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 …


Investigation Of The Characteristic Thermal Retention Behaviour Of Sandwich Glass-Fibre-Reinforced Composite Panels In Electric Oven Designs, Cornelius Ogbodo Anayo Agbo Dec 2022

Investigation Of The Characteristic Thermal Retention Behaviour Of Sandwich Glass-Fibre-Reinforced Composite Panels In Electric Oven Designs, Cornelius Ogbodo Anayo Agbo

Makara Journal of Technology

The focus of this paper is to experimentally investigate the characteristic heating and cooling behaviours of a sandwich glass fibre reinforced composite panel electric ovens. A portable conventional electric oven with two stack trays for product placement was designed and fabricated for the evaluation. The oven box consists of sidewalls and a ceiling made of glass-reinforced plastic (GRP) with sandwich glass wool insulation. The oven floor has, in addition to the sandwich panel, a ceramic tile plate placed on the chamber floor to separate the electric heating element. The oven characteristic thermal behaviour was obtained as different product load conditions …


Three-Phase Ac Induction Motor Speed Control Based On Variable Speed Driver, Abdelrahim Ahmed Mohammed Ate, Rihab Gafar, Xiuyun Sun, Tahleel Abozead Aug 2022

Three-Phase Ac Induction Motor Speed Control Based On Variable Speed Driver, Abdelrahim Ahmed Mohammed Ate, Rihab Gafar, Xiuyun Sun, Tahleel Abozead

Makara Journal of Technology

Massive loss of power is a concern for many countries because of the high power consumption of alternating current (AC) motors. The motor speed should be controlled to alleviate this problem and save more power. This paper proposes a simple simulation for a variable speed driver (VSD) to control the three-phase induction motor speed. The VSD consists of three parts. The converter performs from full bridge diodes to convert single-phase AC voltage into direct current voltage, and then this voltage is filtered by the RL filter and transferred to the last part, which is the inverter. The model was simulated …


Interactive Software-Based Modeling For Gait Analysis Of Musculoskeletal Structures, Nada Masood Mirza, Adnan Ali, Mohamad Khairi Ishak Aug 2022

Interactive Software-Based Modeling For Gait Analysis Of Musculoskeletal Structures, Nada Masood Mirza, Adnan Ali, Mohamad Khairi Ishak

Makara Journal of Technology

Software for interactive musculoskeletal modeling applies diverse scientific and technological concepts to stimulate the movement of musculoskeletal figures. Several tools are available for biomechanical analysis in studying motion and capturing the musculoskeletal representation data to facilitate further evaluation for muscle activation. Musculoskeletal software, such as the OpenSim model, animates, and measures in 3D the structural movement of bones, muscles, joints, ligaments, and such structures in the human body. Users apply graphical interfaces to manipulate the movement science for fast and accurate analysis. OpenSim simulation software features a user-friendly interface to allow the proper clinical application in biomechanics and rehabilitation research. …


Evaluation Of Material Request Order To Support Sustainable Construction, Fajar Susilowati, Nur Nahdiah Anggraeni Aug 2022

Evaluation Of Material Request Order To Support Sustainable Construction, Fajar Susilowati, Nur Nahdiah Anggraeni

Makara Journal of Technology

This study was conducted on one of Indonesia’s apartment projects, in which reinforced concrete is the main structure. Based on existing project data, this project experienced a decline in the construction work’s progress, thus reducing the project’s overall progress. This decline occurred because the delivery of concrete reinforcement material was delayed. This study aimed to determine the process of material request order and its relationship with the work implementation, as well as the factors that influenced the delayed arrival of concrete reinforcement material at the project site. The method used in this study was observation and interview. Data were analyzed …


Design And Implementation Of I2c Bus Protocol On Master And Slave Data Transfer Based On Fpga, Mohamad Khairi Ishak, Meenal Pradeep Kumar Apr 2022

Design And Implementation Of I2c Bus Protocol On Master And Slave Data Transfer Based On Fpga, Mohamad Khairi Ishak, Meenal Pradeep Kumar

Makara Journal of Technology

This paper presents the design of the inter-integrated circuit (I2C) protocol with different types of features, such as combined messages, addressing modes, different data patterns and start addresses, clock frequencies, and types of modes between the field-programmable gate array (FPGA) and test card. Moreover, all these features can be randomized and run for long hours. The FPGA and the test card respectively act as master and slave. The design architecture comprises master and slave. The master generates a START condition, in which the serial data will transact between high to low levels and the serial clock will remain high. Then, …


Mechanical Behavior Of Clay Soil Stabilized With Fly Ash And Bottom Ash, Soewignjo Agus Nugroho, Azra Zulnasari, Ferry Fatnanta, Andius Dasa Putra Apr 2022

Mechanical Behavior Of Clay Soil Stabilized With Fly Ash And Bottom Ash, Soewignjo Agus Nugroho, Azra Zulnasari, Ferry Fatnanta, Andius Dasa Putra

Makara Journal of Technology

Soil is one of the most important aspects of an infrastructure given its functions of receiving and holding structural loads. However, not all soils have good physical and mechanical properties. To overcome those conditions, stabilization of the soil is practiced to meet the technical requirements. This study aims to determine the behavior of high plasticity clay stabilized with lime, fly ash, and bottom ash. These additives can be used as a stabilizing agent to increase soil strength. The percentage of additives varied from 5%–25% then mixed with clay and were tested through the (Unconfined Compression Strength (UCS) test. The UCS …


Enhancement Of Biogas Production Through Solid-State Anaerobic Co-Digestion Of Food Waste And Corn Cobs, Lukhi Mulia Shitophyta, Anisa Salsabila, Firanita Angraini Putri, Siti Jamilatun Apr 2022

Enhancement Of Biogas Production Through Solid-State Anaerobic Co-Digestion Of Food Waste And Corn Cobs, Lukhi Mulia Shitophyta, Anisa Salsabila, Firanita Angraini Putri, Siti Jamilatun

Makara Journal of Technology

Although biogas has been primarily produced through liquid anaerobic digestion, this method leads to the floating and stratification of fibers and non-homogeneous mixing, which can reduce the biogas yield. Alternatively, biogas can be produced by the solid-state anaerobic digestion (SS-AD) of organic material with a high solid content, such as corn cobs. We investigated the co-digestion of food waste and corn cobs as a biomass feedstock for SS-AD in biogas production. We measured the effects of the total solid (TS) content, percentage of food waste, and reduction in volatile solids (VS), from which we determined its appropriate kinetic model. We …


Control Strategy For Solar Energy-Saving Lamps For Optimized Energy Utilization And Sustainability Of Operation Durability: Indonesia Case, Burhanuddin Halimi, Agus Purwadi, Nana Heryana Apr 2022

Control Strategy For Solar Energy-Saving Lamps For Optimized Energy Utilization And Sustainability Of Operation Durability: Indonesia Case, Burhanuddin Halimi, Agus Purwadi, Nana Heryana

Makara Journal of Technology

To solve the electrification ratio issue, the Indonesian government has promoted the use of solar energy-saving lamps. This study proposes a control strategy that adopts current reference time-based profiling for solar energy-saving lamps. For optimal energy consumption, the current reference profile is determined according to users’ daily energy requirements. From the aspect of user comfort, a gradual step reference profile is also introduced to provide a subtle change in lighting intensity level. The proposed control strategy can minimize energy consumption and optimize the operation durability of the system. The concept is verified by simulating four scenarios, the results of which …


Comparison Of Concrete And Steel Jacket Methods For Reinforcing A Concrete Bridge Pier By Numerical And Experimental Studies, Hadi Faghihmaleki Aug 2021

Comparison Of Concrete And Steel Jacket Methods For Reinforcing A Concrete Bridge Pier By Numerical And Experimental Studies, Hadi Faghihmaleki

Makara Journal of Technology

Various rehabilitation and strengthening procedures have been developed in recent decades. A study to determine which methods can be implemented to increase the useful life of the bridge before strengthening must be performed. In this study, the seismic behavior of a reinforced concrete bridge pier with dimension 3.5 × 3.5 m, which was reinforced by two steel and a concrete jacket, was investigated. Nonlinear geometric models and materials were analyzed to estimate the seismic parameters of the pier. Results show an increase in energy absorption, ultimate strength, and ductility for the steel jacket, as well as a greater increase in …


Trend Significance Levels Of Rain Onset And Cessation And Lengths Of The Wet And Dry Seasons In Epe, Lagos State, Nigeria, Adekunle Adedeji Alli, Olorunwa Eric Omofunmi Aug 2021

Trend Significance Levels Of Rain Onset And Cessation And Lengths Of The Wet And Dry Seasons In Epe, Lagos State, Nigeria, Adekunle Adedeji Alli, Olorunwa Eric Omofunmi

Makara Journal of Technology

This study aims to reduce crop failure resulting from a dry spell, which is the first occurrence of unsustainable rainfall that deceives farmers into planting. Thus, trends need to be tested using hypothesis, kurtosis, and other statistics to analyze the risks associated with unstable planting calendars and their possible mitigation strategies. The daily rainfall data from 1982 to 2018 were obtained from the archive of NASA/POWER SRB/FLASH, and the research location is Epe, Lagos State, Nigeria, which lies at latitude 6.585° N and longitude 3.962° E. Microsoft Excel was used to perform the tests. Results show that the null hypothesis …


Music Information Retrieval Based On Active Frequency, Hardianto Wibowo, Wildan Suharso, Yufis Azhar, Galih Wasis Wicaksono, Agus Eko Minarno, Dani Harmanto Aug 2021

Music Information Retrieval Based On Active Frequency, Hardianto Wibowo, Wildan Suharso, Yufis Azhar, Galih Wasis Wicaksono, Agus Eko Minarno, Dani Harmanto

Makara Journal of Technology

Music is the art of combining frequencies. A balance of frequencies gives rise to a harmonious tone. Several features of music can be analyzed, and they include sociocultural background, lyrics, mood, tempo, rhythm, harmony, melody, timbre, and instrumentation. In this study, we use the frequency of instrumentation as a feature for classification because each instrument has a frequency range. To test this frequency range, we use five music genres and one music playing skill. The five genres are dangdut, electronic dance music (EDM), metal, pop/rock, and reggae. The music playing skill is acoustic. Active frequencies are tested using the k-nearest …


Improvement Of Electrical Properties Of Cmc-Pva Doped With Various Contents Of Lino3 As An Application For Hybrid Polymer Electrolytes, Amalia Zulkifli, Norfatihah Mazuki, Ahmad Salihin Samsudin Aug 2021

Improvement Of Electrical Properties Of Cmc-Pva Doped With Various Contents Of Lino3 As An Application For Hybrid Polymer Electrolytes, Amalia Zulkifli, Norfatihah Mazuki, Ahmad Salihin Samsudin

Makara Journal of Technology

The present work was carried out with the development of hybrid polymer electrolytes (HPEs) by using carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) doped with different contents of lithium nitrate (LiNO3) for the determination of their structural and conduction properties. The structural analysis was conducted by using Fourier transform infra-red spectroscopy and showed the interaction between the blend host polymer and ionic dopant, which formed via the coordinating site of CMC-PVA and Li+-NO3−. The complexes of CMC-PVA doped LiNO3 led to an increment in ionic conductivity, as observed by electrical impedance spectroscopy, and the sample containing 20 wt% LiNO3 obtained the highest …