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Mekanika: Majalah Ilmiah Mekanika
Published by Universitas Sebelas Maret
ISSN : 14127962     EISSN : 25793144     DOI : https://doi.org/10.20961/mekanika
Core Subject :
"Mekanika: Majalah Ilmiah Mekanika" is an open-access journal published by Mechanical Engineering Study Program, Faculty of Engineering, Universitas Sebelas Maret. Mekanika invites scholars, researchers and practioners who have interest in mechanical engineering to publish their articles and also provides forums for them to share their works and knowledge. Mekanika focuses on the area of materials engineering and science, design, energy, manufacturing and construction but is not limited to. Both English and Bahasa are accepted in this journal. Mekanika has two issues every year (March and September) and aims to publish more frequently in the future.
Arjuna Subject : Teknik (semua kategori) - Teknik Mesin
Articles 91 Documents
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The Effect of Fumigation and Alkalization on Dimensional Changes of Cantula Fiber Reinforced Unsaturated Polyester Composites Under Immersion M. Ihsan Tri Wibowo; Dody Ariawan; Eko Surojo
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.49463

Abstract

This study aims to investigate effect of fumigation and alkaline treatment on dimensional change in cantula fibers reinforced UPRs composite under immersion test in aqueous environment. Composites were fabricated using compression moulding method with cantula fiber content of 30% vt with the addition of 5% microcrystalline cellulose. Composite specimens were immersed under aquades for 2 months at room temperature. The dimensional changes of cantula fiber reinforced UPRs in different solutions were found to follow a Fickian behavior. Fumigation treated fibers and alkali treated fiber composites after immersion has lower results both in dimensional changes and its slope than untreated fiber composites.
Nanofiber Semiconductor Experiment with Distance Variation Electrospinning Method to Improve DSSC Performance Denny Widhiyanuriyawan; Zainal Arifin; Syamsul Hadi; Muhammad Rijalul Fadli
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.51479

Abstract

Dye-Sensitized Solar Cell (DSSC) is a type of solar cell that uses dyes to transfer sunlight to electrical energy. DSSC construction uses a layered system (sandwich) that consisting of a working electrode and an opposing electrode, both of which are placed on conducting glass and electrolytes to allow electron cycling. This research aims to determine the effect of the distance between the tip and the rotating collector in an effort to increase the efficiency of Dye-Sensitized Solar Cell (DSSC) and examine its impact on the morphology of the ZnO nanofiber. This experiment is carried out by varying the distance between the tip to the rotating collector, which are 4 cm, 6 cm, and 8 cm. The results of this research indicates that at a distance of 8 cm it produces a small, uniform and regular ZnO nanofiber structure with Voc, Jsc, FF, and DSSC efficiency values of 0.559 V, 9.809 mA / cm2, 43.3% and 2.3%. In addition, at a distance of 8 cm it also produces the highest DSSC electrical efficiency from the other distances due to the absorbance of the dye and high electron excitation.
Analysis Nozzle Temperature Effect in 3D Printer Fused Deposition Modelling (FDM) On Mechanical Properties and Characteristics of Polylactic Acid (PLA) Agris Setiawan; Muhamad Alfa Rizky; Untung Sukamto
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.59221

Abstract

The development of the metallurgical industry in the material sector has made significant progress. FDM 3D Printer is a revolutionary technology in Additive Manufacturing (AM). Polylactic Acid (PLA) is a biodegradable and compostable polymer formed from the condensation of lactic acid. This study uses a Nozzle Temperature variation of 210⁰C, 220⁰C, and 230⁰C where shrinkage measurements will be carried out on the test object then Tensile testing, Flexural test, and macrostructural analysis will be carried out to determine the effect of Nozzle Temperature on the test. Based on the results of the study, it was found that the shrinkage produced by 3D Print specimens for Tensile Tests and Flexural Tests at Nozzle Temperature 230⁰C was very high, namely 2.83% and 4.33%, respectively. Nozzle Temperature at 230⁰C produces a fairly high σUTS and σFS of 39.60±2.60 MPa and 49.02±0.76 MPa, respectively. In macrostructural analysis, the Nozzle Temperature porosity at 230⁰C produces the smallest porosity of 0.04 mm2 or 1.46%. In this case, the increase in Nozzle Temperature resulted in a large enough shrinkage as evidenced by the small porosity formed. Therefore, variations in Nozzle Temperature on PLA 3D Printer Specimen greatly affect the mechanical properties of the material.
Frictional Characterization Of Grey Cast Iron Train Brake Block Using A Reduced Scale Dynamometer Bernardus Prasetya Utama; Herru Santoso Budiono; Eko Surojo; Nurul Muhayat
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.48246

Abstract

The brake block is an important component that serves to slow down and stop the train. The safety of this transportation is very dependent on the reliability of this component. One of the important features of the brake block material is the coefficient of friction. The coefficient of friction of the brake block material must meet and match the requirements. The coefficient of friction of a material is measured using a friction test. Previous studies have shown that the friction coefficient of a material is influenced by braking conditions, namely contact pressure and friction speed. Many friction testing methods have been developed to study the characteristics of friction materials.  In contrast to previous studies, in this study, the frictional characteristics of gray cast iron brake blocks were evaluated using a reduced scale dynamometer. The friction test is carried out by pressing the brake block specimen to the surface of the rotating wheel. The specimen size of the brake block and carriage wheels is reduced to 1/4 of the original size. The friction test is carried out at a contact pressure of 0.15,  0.20, 0.25, and 0.30 (MPa) and the friction speeds of 3, 6, 9, and 12 (m/s). The results of this study indicate that the coefficient of friction of the gray cast iron brake block decreases with increasing friction speed and contact pressure.
Design of the Bengawan Unmanned Vehicle (UV) Roboboat: Mandakini Neo Haris Nubli; Fahri Setyo Utomo; Hananta Diatmaja; Aditya Rio Prabowo; Ubaidillah Ubaidillah; Didik Djoko Susilo; Wibowo Wibowo; Teguh Muttaqie; Fajar Budi Laksono
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.61624

Abstract

Mandakini Neo is an autonomous vehicle that was designed and built by the students of the Universitas Sebelas Maret, which was included in the Bengawan Unmanned Vehicle (UV) Roboboat Team to compete in the annual international Roboboat competition of 2021. This competition requires participants to complete several missions; one of the main missions is to move through two gates made from four poles using full automatic navigation, in order to continue on with the other missions. To complete the course, we used Pixhawk and GPS to allow the ship to run automatically, while minimizing the ship’s movement tolerance. The use of Mission Planner software for monitoring, and also for color and shape image processing to help with the reading of objects, along with a sensor fitted on the ship, allowed the mission to be completed. Mandakini Neo was made with the capacity, speed, and comfort of the ship in mind, as well as the ship’s hydrodynamic performance, stability, volume, structural integrity, and construction cost. Following its development we conducted tests of stability, maneuverability, and seakeeping in order to achieve the smallest possible resistance rate; for this purpose, we used the Savitsky method. The manufacture of the ship also required the choosing of the material, the use of the sensor, and also selection of an appropriate system. Finally, the design that we developed was a ship with a catamaran hull type, for which the dimensions had already been calculated, and the proper materials decided, and simple electrical components were able to be obtained for the sensor and the system.
Effect of Holding Time and Temperature of Hot Pressing on Tensile Strength of Biodegradable Plastic Made of Carrageenan Fitrian Imaduddin; Palgunadi Sastra; Wijang Wisnu Raharjo; Putri Wullandari; Ridwan Ridwan
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.64292

Abstract

The most significant environmental problem was caused by plastic. One way to handle plastic waste was using biodegradable plastic because it faster decomposes naturally. Biodegradable plastic can be made from carrageenan by the hot press method. This method can make biodegradable plastic with large dimensions. However, the plastic quality depended on the holding time, temperature, and pressure selected during the hot pressing process. Therefore, this research is conducted to determine the effect of holding time and temperature in the hot press process on the tensile strength of biodegradable plastic made from carrageenan. The composition of the biodegradable plastic material used was 35% carrageenan, 35% polyvinyl alcohol (PVA), and 30% glycerol. In the manufacture of composites, the holding time was varied: 10, 20, 30, and 40 minutes, as well as the process temperature varied from 100, 110, 120, and 130 °C. The tensile strength of the composite was observed through tensile testing using a Universal Testing Machine. FTIR, XRD, and SEM tests were also conducted to sharpen the analysis. The addition of holding time led to an increase in the tensile strength of biodegradable plastics. The highest tensile strength was obtained at a holding time of 30 minutes with a value of 4.45 MPa. After 30 minutes, the tensile strength of the biodegradable composite decreased. Meanwhile, the addition of process temperature caused a decrease in the tensile strength of biodegradable plastics. The highest tensile strength was obtained at a process temperature of 100 °C with a value of 5.28 MPa.
Effect of Alkaline Treatment and Fumigation on the Mechanical Properties of Fiber Unsaturated Polyester-Cantula Composite with Compression Molding Method Muhamad Saifuddin Salim; M. Rafidya Bintang Ramadhan; Elvira Wahyu Arum Fanani; Dody Ariawan; Eko Surojo
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.51493

Abstract

This research examines the strength of the UPRs-Cantula composite with theaddition of filler microcrystalline cellulose (MCC). Composites were createdwith a volume fraction of 30% Vf and a 45° angle. This angle variation receivedthe same treatment as the others, including untreated, alkaline, and fumigation.The treatment time for alkali treatment was 6 hours, while the treatment timefor fumigation was 10 hours. The strength of each angle variation wasdetermined, as well as its treatment of tensile strength, modulus of elasticity,and Poisson's ratio UPRs-cantula composites. According to the results, thealkali treatment produced the highest tensile strength and elastic modulusvalues. The highest Poisson ratio value was discovered without treatment at a45°. The alkaline treatment yielded the highest tensile strength and modulus ofelasticity test results. The pullout fiber fracture dominated the untreatedcomposite fracture, whereas the fiber breakage fracture dominated the alkalinetreatment.
Prospects and State of the Glass Industry in Saudi Arabia and a preliminary assessment of the quality of Glass and Glass-Ceramics Fabrication Essam R. I. Mahmoud; Awaluddin Mohamed Shaharoun; Abdulrahman Aljabri; Hamad Almohamadi; Mohammed Farhan
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.64294

Abstract

Although the economic value of glass products and its importance to the Saudi National Economy is vast, not much information is available about the current state of the art of the industry. Likewise little information is available about the geography, potential sites for mining sand as well as the evaluation of sand quality. This paper attempts to bridge this gap by presenting a feasibility study of fabricating normal glass and glass ceramics from Saudi Arabia’s domestically available raw materials. It discusses the current status of glass industry in Saudi Arabia and the Middle East region. It also gives a brief explanation about the sand topography in Saudi Arabia. In order to determine the feasibility of fabricating glass using these raw materials, experimental data on the fabrication of normal glass and glass-ceramics from indigenously available raw materials was obtained and reported as part of the findings of this paper Firstly, normal transparent glass were able to be fabricated without any apparent large defects using sand collected from Ar-Rayis region in Saudi Arabia. Four nano-sized crystallization catalysts, namely VC, WC, TiC and Y2O3, were added to the constituents of the glass in 3 wt.%.  For VC, the crystallization process was limited. The glass ceramics of WC consisted of multi-dimensional edges crystals which covered all the matrix. Gray crystalline whiskers were obtained by addition of TiC. The Y2O3- glass ceramics consisted of multi-directionally rosette crystals. Finally, the microhardness values of the added crystallization catalysts glass ceramics were obtained and found to be much higher compared to normal glass. The results show that glass of high quality can be produced specifically for Ar—Rayis region which would be of interest to researchers, glass industry personnel and potential investors
Experimental Test of Ignition Timing with Programable CDI on Performance Single Cylinder Otto Engine Rendy Adhi Rachmanto; Martinus Darmawan Bagas Wijayanto; Wibawa Endra Juwana; Pramodkumar Siddappa Kataraki
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.58951

Abstract

Ignition timing is sparking from the spark plug based on the ignition angle during the compression stroke in the combustion chamber relative to the piston position and the crankshaft angular speed. Adjusting the ignition angle is one method to optimize the combustion process in the engine. An optimal combustion process can improve engine performance and reduce fuel consumption. This study investigates optimal data from ignition angle changes using a programmable CDI. The test was performed on a single-cylinder fourstroke Otto engine with standard ignition angle variations, +3°, +6°, and +9° before TDC. The test results show that torque and power have increased while brake-specific fuel consumption has decreased. Optimal data acquisition at ignition angle of +9° with peak torque value of 6.91 Nm and peak power value of 4.80 kW, while the lowest value of specific fuel consumption is 0.234 kg/kWh, and the highest value of thermal efficiency is 36 %. From this study, it was concluded that the ignition timing could affect the engine performance.
Experimental Study Influences Changes In Compression Ratio To Performance Of Single Cylinder Otto Engine Wibawa Endra Juwana; Rendy Adhi Rachmanto; Mugi Wiyono; Iwan Istanto
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 2 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i2.59487

Abstract

Increasing the compression ratio is an attempt to increase the efficiency and performance of the engine. The purpose of the study was to analyze the effect of changes in the compression ratio on engine performance. Tests using a single-cylinder Otto engine by comparing the performance of an enlarged compression ratio of 9.7:1 and 10.4:1 with a standard compression ratio of 9.0:1. The result of the research is that the compression ratio of 9.7:1 produces a peak torque of 7.51 Nm at 6000 rpm, a peak power of 5.30 kW at 8000 rpm, and the lowest BSFC is 0.146 kg/kW.h at 6000 rpm. Torque and power increased by 0.09 Nm and 0.28 kW, and BSFC decreased by 0.018 kg/kW.h compared to the standard compression ratio of 9.0:1. Using a compression ratio of 10.4:1 produces a peak torque of 7.69 Nm at 6000 rpm, a peak power of 5.38 kW at 8000 rpm, and the lowest BSFC is 0.116 kg/kW.h at 6000 rpm. Torque and power increased by 0.27 Nm and 0.36 kW, and BSFC decreased by 0.030 kg/kW.h compared to the standard compression ratio of 9.0:1.

Page 7 of 10 | Total Record : 91

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