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Jurnal Polimesin
Published by Politeknik Negeri Lhokseumawe
ISSN : 16935462     EISSN : 25491199     DOI : http://dx.doi.org/10.30811/jpl
Core Subject : Science, Engineering,
Automotive Engineering Control & Systems Engineering Engineering Materials Science & Nanotechnology Mechanical Engineering
Polimesin mostly publishes studies in the core areas of mechanical engineering, such as energy conversion, machine and mechanism design, and manufacturing technology. As science and technology develop rapidly in combination with other disciplines such as electrical, Polimesin also adapts to new facts by accepting manuscripts in mechatronics. In Biomechanics, Mechanical study in musculoskeletal and bio-tissue has been widely recognized to help better life quality for disabled people and physical rehabilitation work. Such a wide range of Polimesin could be published, but it still has criteria to apply mechanical systems and principles. Exceeding the limitation has been a common reason for rejection by those outside the scope. Using chemical principles more than mechanical ones in material engineering has been a common reason for rejection after submission. Excessive exploration of the management within the discipline of Industrial Engineering in the manufacturing technology scope is also unacceptable. The sub-scope biomechanics that focuses on ergonomics and does not study movement involving applied force on the bio-tissue is also not suitable for submission.
Arjuna Subject : Teknik (semua kategori) - Teknik Mesin
Articles 611 Documents
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Performance evaluation of a laboratory-scale Pelton turbine under variable nozzle distance and valve opening Aini Lostari; Didik Sugiono; Miftahul Ulum; Umi Kulsum; Yudi Hartono
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8200

Abstract

Pelton turbines are impulse turbines widely used in micro-hydro power systems operating under high-head and low-flow conditions. Their performance depends strongly on the quality of the water jet impacting the runner buckets, which is influenced by nozzle distance and valve opening. This study experimentally investigated the effects of nozzle distance (60, 70, and 80 mm) and valve opening (30°, 60°, and 90°) on the hydraulic power, turbine power, electrical power, and efficiency of a laboratory-scale Pelton turbine. Turbine rotational speed was measured using a tachometer, while voltage and current were measured using a multimeter to determine power output. The results showed that increasing the valve opening increased hydraulic, turbine, and electrical power due to higher flow rate and jet kinetic energy. However, the turbine efficiency showed non-linear behavior because it was influenced by the quality of the jet and the effectiveness of momentum transfer. The maximum turbine power of 10.52 Watts and electrical power of 10.58 Watts were obtained at a nozzle spacing of 80 mm and a valve opening of 90°. Meanwhile, optimum efficiency was achieved at a nozzle distance of 80 mm and a valve opening of 30%, indicating that optimum conditions do not always occur at maximum flow. The results of this study indicate that the combination of nozzle distance and valve opening significantly influences Pelton turbine performance and is important for optimizing laboratory-scale micro-hydro systems.
Performance assessment of an R290 air conditioning system using hybrid ZnO–SiO₂ nanolubricant Agung Nugroho; Tabah Priangkoso; Muhammad Alaik Amirullah; Indah Hartati; Fatna Nur Hidayah; Kofi Ampomah Benefo
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8924

Abstract

This study investigates the performance of a split air conditioning system using hybrid ZnO–SiO₂ nano lubricant with R290 refrigerant. Experiments were conducted under steady-state conditions at an ambient temperature of 27 ± 1°C with a constant cooling load. Nano lubricant concentrations of 0.18%, 0.36%, 0.91%, 1.79%, and 2.67% by mass were prepared using a two-step dispersion method involving mechanical stirring and ultrasonic agitation. System performance was evaluated based on energy consumption and Coefficient of Performance (COP). The results show that the addition of ZnO–SiO₂ nano lubricant improves system performance at optimal concentrations. The highest performance was observed at concentrations of 0.36% and 0.91%, resulting in an energy consumption reduction of approximately 9.7% compared to pure lubricant. The maximum COP value of 2.77 was obtained at a concentration of 0.91%. However, further increases in nanoparticle concentration led to performance degradation due to increased viscosity and particle agglomeration, which negatively affected compressor work and heat transfer. These findings indicate that the application of ZnO–SiO₂ nano lubricant can enhance the energy efficiency of air conditioning systems when applied at optimal concentrations.
Influence of machining parameters on cutting performance and wear mechanisms of coated carbide tools Fransnazoan Sitorus; Naqasya Asyrori Sidabutar; Sumawijaya Suyatno; Ulfani Ikhwana Purba; Derlini Derlini
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8964

Abstract

In coated carbide cutting tools, the coating layer functions as a solid lubricant that improves wear resistance and minimizes frictional and thermal effects during machining. This study investigates the influence of machining parameters on cutting performance and characterizes the coating material and WC/Co carbide substrate to better understand their relationship with tool wear behavior. The machining parameters were established through an experimental design that evaluated mechanical loading, thermal loading, and chemical interactions using microstructural analysis. The experimental design evaluated the effects of mechanical loading, thermal loading, and chemical interactions through wear and microstructural analysis. Under mechanical loading, machining of Al-6061 produced mild abrasive wear with flank wear (VB) of 0.07 mm, while AISI 1070 generated higher edge wear of 0.25 mm. Under thermal loading, a 20% increase in cutting speed resulted in VB of 0.10 mm for Al-6061, whereas a 20% reduction in cutting speed for AISI 1070 produced VB of 0.16 mm accompanied by plastic deformation. Chemical interaction analysis showed stable coating integrity without delamination during Al-6061 machining. In contrast, AISI 1070 machining caused partial diamond film loss and substrate exposure, with approximately 35% diamond film remaining after wear progression. The results indicate that tool wear behavior is mainly controlled by mechanical loading, while thermal and chemical effects remain secondary. Abrasive wear was identified as the dominant wear mechanism, causing progressive coating removal without catastrophic delamination.
Thermodynamic performance evaluation of a steam turbine at kamojang geothermal power plant using operational data Firmansyah Firmansyah; Fahrudin Fahrudin; Damora Rhakasywi; Regina Natalindah Lumbantoruan; Fazli Iqbal Pasha; Putty Fauthyda Zahra Hapidzha
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8953

Abstract

Geothermal power plants play a significant role in sustainable energy systems due to their ability to provide stable baseload electricity with relatively low carbon emissions. This study investigates the thermodynamic performance of the steam turbine at Kamojang Geothermal Power Plant Unit X using operational data collected over 29 days and processed into 6-hour averages to represent the local operating envelope around the turbine design point. A multiple linear regression model was developed to evaluate the effects of steam mass flow rate, inlet steam pressure, inlet steam temperature, and condenser pressure on turbine isentropic efficiency. The results indicate that inlet steam pressure, inlet steam temperature, and condenser pressure significantly influence turbine efficiency, whereas steam mass flow rate has no significant effect. The model explains 43.8% of the variation in turbine isentropic efficiency (R²=0.438) and yields a low in-sample prediction error (MAPE=0.12%), indicating that the regression closely reproduces the observed data within the limited operating range. In contrast, a considerable portion of the variation remains unexplained. Condenser pressure was identified as the dominant influencing parameter. These findings suggest that local deviations from the design point may contribute to off-design operation and additional thermodynamic irreversibility, providing practical implications for performance monitoring and operational optimization in geothermal power plants.
Effect of alkali fusion temperature on the synthesis and characteristics of nanosilica from silica sand Muhammad Sadat Hamzah; Muchsin Muchsin; Abdul Muis; Dino Hasyim; Iqrham Dwi Putra Annas; Muhammad Syaiful Fadly; Bakri Bakri; Sri Chandrabakty
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8695

Abstract

The increasing demand for nanosilica in industrial applications has encouraged the utilization of abundant natural silica sand as a sustainable raw material. This study investigates the effect of alkali fusion temperature on the synthesis and characteristics of nanosilica derived from silica sand from Central Sulawesi, Indonesia. A cost-effective, energy-efficient synthesis method is needed to transform raw sand into high-value nanoparticles with controlled morphology. The study employed the alkali fusion method, where silica sand was reacted with NaOH at temperatures ranging from 400°C to 700°C, followed by leaching and titration to pH 7-8 to produce nanosilica. Characterization results via XRF and XRD confirmed that the synthesized nanosilica maintains a high SiO2 concentration (up to 72.46%) and exhibits a coexistence of amorphous phases and crystalline quartz. Morphological analysis by TEM revealed that increasing the fusion temperature decreases particle size from 18.91 nm at 400°C to 14.00 nm at 700°C, indicating that higher thermal energy promotes structural decomposition. These findings suggest that the alkali fusion temperature is an important parameter for controlling nanosilica dimensions. Further evaluation, including yield and recovery analysis, is required to assess process efficiency and its potential for large-scale applications.
Performance, energy balance, and emission characteristi-cs of a spark ignition engine fueled with gasoline and LPG Marthen Paloboran; Thesya Atarezcha Pangruruk; Ismail Rahim; Juhamri Juhamri; Auliya Rahmatul Ummah; Erlyne Nadhilah Widyaningrum
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8906

Abstract

Efforts to reduce greenhouse gas emissions continue to encourage the transition from liquid fossil fuels to gaseous fuels, as gaseous fuels are expected to provide cleaner combustion and lower hydrocarbon emissions. This study aimed to evaluate the performance of a spark ignition engine with a carburetor fuel system operated using gasoline and Liquefied Petroleum Gas (LPG), and to analyze its energy balance based on the First Law of Thermodynamics. The energy balance consisted of input energy from air and fuel, useful output energy, and energy losses during combustion. The engine was operated at speeds ranging from 2000 to 5000 rpm. Fuel consumption was measured after the engine consumed 50 mL of gasoline and 50 g of LPG. The results showed that emissions of HC, CO, and CO2 from LPG were lower than those from gasoline. The useful energy produced by LPG combustion was lower than that of gasoline; however, LPG showed higher thermal efficiency due to lower Specific Fuel Consumption (SFC) and reduced energy losses. The conversion from gasoline to LPG in a carburetor system reduced emissions by approximately 7–73%, whereas the average reduction in an electronic fuel injection system was reported at 11–15%.
Performance and emission analysis of a Komatsu PC195LC common-rail diesel engine under injector type and spray-angle variations Yosephus Ardean Kurnianto Prayitno; Sugiyanto Sugiyanto; Ilham Ayu Putri Pratiwi; Braam Delfian Prihadianto; Muhammad Fauzan; Setyawan Adi Nugraha; Josua Aditya Manuel; Sutikno Sutikno; Muhammad Novan Budi Prasetya
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8292

Abstract

Injector condition and spray characteristics strongly influence fuel atomization, combustion efficiency, and exhaust emissions in common-rail diesel engines. This study aims to evaluate the performance and emission responses of a Komatsu PC195LC diesel engine under variations in injector type and spray angle by integrating field measurements with bench-scale spray characterization. Two injector types (OEM vs local) were tested at 1050, 1500, and 2050 rpm; fuel rate and specific fuel consumption were logged over two-minute windows, and post-operation (3000 h) inspections assessed wear. A back-lit imaging rig measured spray angle and droplet distribution at 50 and 100 bar; a simple mixing–atomization model linked spray metrics to air–fuel preparation. Field results show the OEM injector reduced fuel rate by 0.78 L/h (3.45%) versus the local unit under the duty cycle tested. Bench data indicate wider spray angles and finer droplets at higher pressure, consistent with improved mixture formation. Joint analysis attributes the observed SFC gains to healthier nozzle geometry and spray targeting. The study provides guidance on injector selection, condition monitoring, and pressure/angle calibration towards Euro-4-aligned efficiency and emissions.
Interfacial modification of high-loading sugar palm fiber/unsaturated polyester biocomposites using alkali–vinyltrimethoxysilane treatment Fahriadi Pakaya; Yurika Nantan; Marinus S. Tappy; I Nyoman Subawa
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8946

Abstract

Natural fiber-reinforced polyester biocomposites are promising lightweight materials, but their performance is often limited by weak fiber–matrix interaction, especially at high fiber loading. This study investigates the effect of combined alkali–Vinyltrimethoxysilane (VTMS) treatment on the flexural and physical properties of sugar palm fiber-reinforced Unsaturated Polyester Resin (UPR) biocomposites. Untreated fiber composites (IU/UPR), NaOH-treated fiber composites (IA/UPR), and NaOH–VTMS-treated fiber composites (IAS/UPR) were fabricated using the hand lay-up method at fiber loadings of 0–50 wt.%. The results showed that IAS/UPR exhibited the best overall performance, particularly at 50 wt.% fiber loading, achieving a flexural strength of 110.59 MPa, compared with 37.20 MPa for IU/UPR and 50.60 MPa for IA/UPR. IAS/UPR also showed lower water absorption, higher density, and lower porosity. Two-way ANOVA confirmed that fiber treatment, fiber loading, and their interaction significantly affected flexural strength, water absorption, and porosity. FTIR analysis indicated the reduction of hemicellulose and lignin-related components, while SEM observations showed improved matrix coverage, fewer interfacial gaps, and reduced fiber pull-out. These results indicate that alkali–VTMS treatment improves interfacial compatibility and extends the effective fiber-loading range of sugar palm fiber/UPR biocomposites.
Effect of washing and torrefaction pretreatments on fuel properties of rice husk-based bio-pellets Alchalil Alchalil; Rizky Iskandar; Adi Setiawan; Zulmiardi Zulmiardi; Athiyah Rana; Azhar Syahputra
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.9120

Abstract

Rice husk is an abundant agricultural waste in Indonesia and has potential as a biomass fuel for co-firing in steam power plant boilers. This study investigated the effects of washing and torrefaction pretreatments on the fuel properties of rice husk-based bio-pellets to reduce ash content and improve calorific value. Rice husk was washed using water at 70 ± 5°C under two conditions, with stirring and without stirring, while untreated rice husk was used as a control. Torrefaction was conducted at 260°C, and the treated biomass was pelletized using tapioca starch as a binder at 30% of the raw material weight. The results showed that the lowest ash content (26.362%) was obtained from bio-pellets produced from rice husk washed without stirring, indicating that washing was effective in reducing ash content. The highest calorific value (4456.4 kcal/kg) was recorded in bio-pellets produced from untreated rice husk, while the highest combustion rate (0.504 g/min) was observed in the washed and torrefied samples. The findings indicate a trade-off between ash reduction and energy performance, depending on the pretreatment combination. However, all samples showed relatively high ash content (26%–36%), which may limit their direct suitability for co-firing without further ash reduction treatment.
Predictive efficiency analysis of biomass boilers using torrefied tropical fruit residues and washed wood waste Hadi Prayitno; Ricky Syahputra Tarigan; Ahmad Fauzan; Aryanda Fitrah Fardano; Muhammad Hlimy Assydiqie; Murtadho Agung Pratama
Jurnal Polimesin Vol 24, No 3 (2026): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i3.8722

Abstract

Biomass-fired boilers are widely used in agro-industrial steam generation, yet their efficiency remains sensitive to fuel quality, boiler configuration, and the calorific value basis. This study developed a predictive thermal-efficiency assessment of four industrial biomass boilers, namely ZUG, Djaja Teknik, Vickers, and Isgec, by integrating biomass fuel characterisation, field operating data, and Hugot’s direct-efficiency model. Its novelty lies in linking calorific-value changes in torrefied tropical fruit residues and distilled water-washed wood waste to boiler-specific operating parameters, rather than treating fuel upgrading as laboratory fuel improvement alone. Gross Calorific Value (GCV) was used as the primary basis for modelling, while NCV efficiency was calculated only when supporting fuel data were available. Baseline results showed GCV-based efficiencies of 77.12% for ZUG and 80.63-81.05% for Djaja Teknik, whereas Vickers and Isgec corresponded more closely to NCV-based efficiencies of 72.24% and 68.71–70.34%, respectively. Distilled water washing changed wood-waste GCV from 3,891-4,812 to 4,343-5,323 kcal/kg, with champaca increasing by approximately 21.6%. Torrefaction yielded higher GCV values of 6,519.28, 6,661.58, and 6,875.60 kcal/kg for coffee husk, cocoa shell, and mangosteen shell, respectively. Under fixed-flow Hugot assumptions, higher GCV increased fuel-energy input and could reduce numerical ηGCV, indicating model sensitivity rather than poorer fuel performance. The findings support SDGs 7, 12, and 13 through renewable heat assessment, biomass residue valorisation, and low-carbon energy pathways, while remaining limited to predictive boiler thermal efficiency.

Page 61 of 62 | Total Record : 611

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