Jurnal Teknik

Pengaruh Cutting Speed dan Laser Power Proses Fiber Laser Cutting Terhadap Kekasaran Permukaan Pada Baja AISI 1040 Dengan Ketebalan 6mm

Febi Rahmadianto, Gerald A. Pohan, Kenzha Yanuar (Author) — Mon, 01 Dec 2025 00:00:00 +0000

Surface roughness is a measure of microscopic irregularities on a material's surface that affects the performance, service life, and aesthetics of a product. This study analyzes the effect of cutting speed and Laser Power in the fiber Laser Cutting process on the surface roughness of 6 mm thick AISI 1040 steel. The method used was true experimental research with variations in cutting speed (500, 1000, 1500 mm/min) and Laser Power (80%, 90%, 100%). The results show that the combination of 1000 mm/min cutting speed and 80% Laser Power produced the lowest roughness of 2.3 µm, while the combination of 500 mm/min and 90% produced the highest roughness of 29.36 µm. Increasing Laser Power generally increases roughness, except at 100% Laser Power with 500 mm/min cutting speed which decreased due to more uniform material melting. The conclusion of this study is that optimal parameters (cutting speed 1000 mm/min and Laser Power 80%) produce a smooth surface. These findings can be a reference for the manufacturing industry in improving product quality through Laser Cutting process optimization.

Pemilihan Parameter Proses Pembubutan Dalam Menentukan Kekasaran Permukaan N7 Baja ST 41

Mon, 01 Dec 2025 00:00:00 +0000

The turning process is a machining process on a cylindrical workpiece to produce a material profile as designed. The surface of the workpiece being machined produces rough scratches. The surface roughness of the workpiece is an indicator of the quality of the resulting surface. In machine construction, the surface roughness value has been determined by the designer according to the construction needs.The manufacturing process must be capable of forming metal and producing predetermined surface roughness values. The surface roughness value of the workpiece is influenced by several factors such as cutting parameters, cutting tools, coolant system, etc. This research was conducted to determine cutting parameters, especially cutting conductivity on the resulting surface roughness value. The study was carried out using a lathe and a carbide-type cutting tool to cut ST 41 steel. The cutting parameters were cutting speeds of 200, 215, 230, 245, and 260 (m/min), feeding, and depth of cut. Before machining is carried out, the cutting possibility of N7 is determined, namely 1.6 microns, based on the design of the shaft construction. To determine the roughness value to be achieved, the turning process is carried out by varying the cutting speed, cutting pass 0.1, 0.2, and 0.3 (mm/rev), while the depth of cut is 0.5 mm. After the cutting process is carried out, the surface roughness of the workpiece is measured. From the results of observations and measurements, it was found that the parameters closest to the desired surface roughness N7 (1.6) were cutting speed (Vc) 245 (m/min), feeding (f) 0.1 (mm/rev), and depth of cut (a) 0.1 mm with a roughness value of 1.63 µm.

Studi Komparatif Rencana Anggaran Biaya Klinik PT. Delta Subur Permai Berdasarkan SNI

Syamsu Basiri, Malik Ibrahim, Mukhtar Lutfie (Author) — Mon, 01 Dec 2025 00:00:00 +0000

PT. Delta Subur Permai (DSP) is a subsidiary of Kencana Agri Group operating in Batui District, Banggai Regency, Central Sulawesi. This company is engaged in oil palm cultivation; however, since its establishment, it has lacked adequate health facilities, resulting in suboptimal employee health services. For this reason, the company took the initiative to build a clinic that supports the health needs of its workers. In the planning process, the budget plan data used by the contractor still refers to the contractor's internal calculation method. Therefore, this study focuses on analyzing the Cost Budget Plan (RAB) for clinic construction using the SNI analysis method. The objectives of this study are determine the RAB for PT DSP's clinic construction based on unit prices from the Banggai Regency Government with SNI analysis and to compare more efficient methods in preparing the RAB. The study employed a comparative quantitative method, specifically comparing variable values across different populations or samples. The results showed that the RAB value using the SNI method was Rp. Rp. 313,300,820, which is higher than the contractor's method of Rp. 297,186,771. This confirms the difference in calculation results between the two methods.

Pemanfaatan Limbah Oli Bekas Sebagai Bahan Bakar Alternatif Untuk Kompor Bertekanan Udara

Mahrus Khoirul Umami, Ibnu Irawan, Wildan Alim, Zainal Arifin (Author) — Wed, 28 Jan 2026 00:00:00 +0000

As the number of vehicles increases, the amount of used oil waste also increases. Used oil waste can be used as an alternative fuel energy for stoves. In the combustion process of used oil, the mixture of air and fuel can affect the achievement of optimal temperature by applying the right AFR (Air Fuel Ratio). The chemical formula of used oil can be known using the GC-MS (Gas Chromatography-Mass Spectrometry) test. The purpose of this study is to calculate the stoichiometric AFR, determine the resulting combustion temperature, then the combustion time at each variation of air mass rate of 0.00193 kg/s, 0.00276 kg/s, 0.00359 kg/s, 0.00442 kg/s and 0.00525 kg/s. The results of the GC-MS test of used oil obtained the chemical formula C22H46, so the stoichiometric AFR is 14.8:1. Stoichiometric combustion occurs at an air mass rate of 0.00359 kg/s producing a flame temperature of 876.8°C and a furnace temperature of 535.2°C, with a combustion duration of 1627 seconds, producing a blue flame across the furnace surface as an indicator of low emission values and no soot. The combustion value with the highest temperature occurs at an air mass rate of 0.00525 kg/s, namely 1124°C, on the flame and 694.6°C on the furnace with a combustion duration of 1229 seconds. The lowest temperature occurs at a mass rate of 0.00193 kg/s, namely 767.5°C on the flame and 290.8°C on the furnace with a combustion duration of 2224 seconds. This study can be concluded that the greater the air mass rate, the higher the combustion temperature value so that the combustion is faster. This used oil stove can be an alternative new technology, which can replace people's dependence on gas stoves and become a solution for environmentally friendly stoves that do not emit soot in their combustion.

Evaluasi Sistem Pelaporan Kekerasan Seksual di Perguruan Tinggi: Pendekatan Black-Box dan Kepatuhan terhadap Permendikbudristek No. 30/2021

Nursetia Wati, Ismail Mohidin, Fajar Hermawanto, Salman Suleman (Author) — Mon, 01 Dec 2025 00:00:00 +0000

The sexual violence reporting system is a critical component in creating a safe and responsive campus environment for victims. This study aims to evaluate a web-based sexual violence reporting system implemented at a higher education institution by integrating Black-Box Testing and Compliance Testing approaches. The evaluation assesses both the system’s functional performance from a user perspective and its adherence to relevant regulations, particularly Permendikbudristek No. 30 of 2021. The results of Black-Box Testing indicate that most features function properly, although some issues were found in error messaging and the usability of anonymous reporting options. Meanwhile, Compliance Testing shows that the system fulfills most regulatory indicators, but there are still weaknesses in access control to victim data by internal staff. These findings highlight the importance of comprehensive evaluation in systems dealing with sensitive issues to ensure both technical reliability and compliance with principles of justice and victim protection.

Physicochemical Characterization and Epoxidation of Jatropha Curcas Oil for Eco-Friendly Engine Lubricant Applications

Wed, 28 Jan 2026 04:58:55 +0000

This study aims to explore the potential of castor oil (Jatropha curcas L.) as a plant-based alternative engine lubricant and compare it to commercial mineral-based lubricants. The research process includes drying Jatropha seeds and epoxidizing the oil using oxidizing agents (H₂O₂) and (CH₃COOH) with variations of (1:0.075; 1:0.15; 1:0.225; and 1:0.30). Chemical testing was conducted to analyze the acid number of the oil, while physical testing was carried out to measure its viscosity index, flash point, and pour point. The results show that Jatropha oil has an acid number of 5.30, a viscosity index of 217, a flash point of 270°C, and a pour point of 0°C. Therefore, Jatropha oil demonstrates potential as a base material for engine lubricants due to its relatively high flash point, which approaches that of polyol ester (POE)-based oils. However, further modification with additives is required to lower its pour point, ensuring it remains fluid in colder climates such as those in subtropical regions.

COMPARATIVE ANALYSIS OF CORROSION INHIBITOR EFFECTIVENESS FOR ALUMINIUM PROTECTION

Mon, 01 Dec 2025 00:00:00 +0000

Corrosion poses a significant challenge in the use of aluminum, particularly Aluminum 6061, which, despite its favorable strength-to-weight ratio, is highly susceptible to degradation in aggressive environments such as acidic, alkaline, and saline media. While synthetic chemical inhibitors are commonly employed to mitigate corrosion, their environmental impact raises substantial concerns. This study aims to compare the effectiveness of coconut oil, palm oil, and soybean oil as eco-friendly corrosion inhibitors for Aluminum 6061 in three corrosive environments: HCl (acidic), NaOH (alkaline), and NaCl (saline) solutions. A quantitative experimental approach was employed using the weight-loss method to evaluate the corrosion rate based on mass changes before and after exposure. The findings indicate that all three vegetable oils significantly reduce the corrosion rate compared to untreated specimens. Coconut oil exhibited the highest inhibitory performance, followed by soybean oil and palm oil. This effectiveness is attributed to the organic compounds and fatty acids in the oils, which adsorb onto the metal surface and form a protective layer that limits interaction with corrosive ions. These results support the development of sustainable, bio-based corrosion inhibition technologies as viable alternatives to synthetic chemicals, with promising applications across industries that utilize aluminum.

Analisis Ketahanan Tanah berdasarkan Kecepatan Gelombang Geser (VS) di Kawasan Aliran Sungai Muara Bangkahulu Bagian Hilir, Kota Bengkulu

Mon, 01 Dec 2025 00:00:00 +0000

The downstream area of the Muara Bangkahulu River is a developing area in Bengkulu City that was affected by major earthquakes in 2000 and 2007. The risk of earthquake-induced damage in this area requires further investigation, particularly regarding soil resistance to seismic shaking. This study aims to analyze soil characteristics based on shear wave velocity (VS), site classification, and Ground Amplification Factor (GAF) to support earthquake-resistant infrastructure planning. This study uses microtremor data inversion methods conducted at 38 measurement points. Shear wave velocity (VS) data at depths of 10–50 m were analyzed to determine site classes and Ground Amplification Factor (GAF). Data processing was performed using surface wave inversion techniques to map VS distribution and seismic amplification. The results of the study show that VS values at depths of 10–50 m vary between 160–960 m/s, with site class classifications dominated by categories C (hard soil) and D (medium soil). The Ground Amplification Factor (GAF) values ranged from 1.1–1.9, with areas of high amplification indicating greater vulnerability to earthquake shocks. These findings serve as an important reference for disaster mitigation planning and earthquake-resistant infrastructure development in the region. Technical recommendations are needed for locations with high amplification to minimize the risk of earthquake damage in the future.

Analisis Faktor Teknis dalam Risiko Penyelenggaraan Proyek Bangunan Gedung Pemerintahan

Fauzi Sitompul, Nasfryzal Carlo, Zaitul Zaitul (Author) — Mon, 01 Dec 2025 00:00:00 +0000

The construction industry faces high uncertainty due to economic fluctuations, regulatory changes, and resource limitations. In South Tapanuli, construction projects often experience delays, budget overruns, and quality issues due to economic factors. This study aims to identify the most dominant economic risks in building construction. Using AS/NZS 4360:2004 and the Relative Importance Index (RII), this research analyzes the impact of raw material price fluctuations, delayed payments, labor wage increases, and regulatory changes. Findings indicate that raw material price fluctuations (RII: 0.948) and delayed payments (RII: 0.934) are the highest risk factors. Financial risks pose major challenges, requiring effective mitigation strategies. Recommendations include stabilizing material prices, reforming payment systems, and improving labor wage management. Proper policy implementation can enhance efficiency and project sustainability in this region.

Perilaku Pengunjung Ruang Publik Kawasan Masjid Nurul Bahri dengan Metode Place Center Mapping

Nurmiah, Febriyanti Karim, Umar Umar, Indriani Umar (Author) — Mon, 01 Dec 2025 00:00:00 +0000

Nurul Bahri Mosque possesses strong potential as a public open space, supported by its scenic offshore coastal view that enhances the visual quality and attractiveness of the area. The mosque courtyard and surrounding open space function multifunctionally, accommodating religious, social, and recreational activities through pedestrian pathways that encourage visitor movement and interaction. However, many of these activities are not yet supported by adequate infrastructure, resulting in the suboptimal performance of the mosque courtyard’s dual role as both a place of worship and a tourism-oriented public space. This study examines the formation of activity spaces within the public open space of the Nurul Bahri Mosque by analyzing the relationship between spatial characteristics and visitor behavior. The research employs a behavioral approach using a system mapping technique, conducted objectively based on the time and spatial position of observed activities, applying Place-Centered Mapping and Person-Centered Mapping. The findings indicate that visitor behavior generates natural and context-driven activity patterns. No significant transformation of spatial dimensions is observed; however, variations in space utilization emerge across zones. Zone 2 shows distinctive activity patterns influenced by fishing activities and coastal proximity but lacks supporting street furniture, while Zone 3 accommodates core and supporting activities, including pedestrian crossings, without adequate infrastructure. These findings provide a basis for future spatial planning and facility development within the mosque area.

Optimization Design of 600 Wp Solar Tree System Design According to Tilt Angle

Mon, 01 Dec 2025 00:00:00 +0000

This paper describes the design optimization of the 600 Wp Solar Tree System, with a focus on determining the optimal tilt angle. The purpose of this study is to analyze and determine the optimal tilt angle and evaluate the performance of the system in three different locations on the campus of Universitas Jenderal Achmad Yani (UNJANI). The methods used in this study include analysis of solar radiation data at 0° azimuth and different tilt angles (15° to 30°) using PVSyst. software and system performance parameters such as Solar Fraction (SF), Performance Ratio (PR), and Normalized Production. Based on the results, the optimal tilt angle is 15° with a maximum annual solar irradiation of 1912 kWh/m². Performance simulations of the three sites showed similar results, with all three sites producing the best performance with 92.66% SF and 57.76% PR. The system generated the lowest unused energy of 199.56 kWh/year. The research conducted gives important guidelines for optimizing the design of the 600 Wp Solar Tree System implemented on the collages

Analisis Usability Website Simapres Pemerintah Kabupaten Wonogiri dengan Pendekatan System Usability Scale

Perdana Suteja Putra, Grahita Prisca Brilianti, Adhe Rizky Anugerah (Author) — Thu, 29 Jan 2026 05:53:44 +0000

This study aims to evaluate the usability of the Simapres website of the Wonogiri Regency, which is used to manage scholarships for students from state universities in Wonogiri. Usability was assessed using the System Usability Scale (SUS) method, which includes ten statements to measure effectiveness, efficiency, and user satisfaction. The study involved 15 respondents who were scholarship recipients in Wonogiri. The results show that the Simapres website received an average SUS score of 80.3, which falls into the "Acceptable" and "Excellent" categories based on user ratings. Although the website was rated as effective and efficient, some respondents provided suggestions for improvements in features and user interface. This study provides recommendations for system improvements to enhance user experience and the quality of technology-based public services in Wonogiri.