Jurnal Teknik

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

2026-02-03T06:52:18+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-03T06:46:16+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-02T08:16:53+00:00

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

2026-02-02T08:16:54+00:00

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

2026-02-05T13:15:59+00:00

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

2026-02-02T08:16:54+00:00

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

2026-02-09T01:54:54+00:00

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.

Pengembangan Nutri-Bumil dengan Model APPED Berbasis Website Terintegrasi Chatbot

2026-02-09T02:02:48+00:00

This study aims to develop the Nutri-Bumil System, a web-based nutrition intake monitoring service for pregnant women integrated with a chatbot. The system development employed a Research and Development (R&D) approach using the APPED model (Analysis, Planning, Production, Evaluation, and Distribution). The research instruments included validation by content experts and media experts using a 4-point Likert scale, which was converted into percentages to assess the system’s feasibility based on the ISO/IEC 25010 software quality standards in the aspects of Usability, Functional Suitability, and Performance Efficiency. The validation results showed that content experts rated the system at 80.71% for Usability, 82.65% for Functional Suitability, and 76.78% for Performance Efficiency, which fall into the categories of Feasible and Fairly Feasible. Meanwhile, media experts provided scores of 80%, 85.41%, and 87.5%, all of which are categorized as Feasible. These findings indicate that the developed Nutri-Bumil system meets the software quality aspects in terms of ease of use, functional suitability, and performance efficiency. Overall, the system is declared Feasible for use as an adaptive, accurate, and efficient digital nutrition service supporting the needs of pregnant women and nutrition professionals.

Karakteristik Beton Dengan Menggunakan Limbah Kaca Sebagai Bahan Penganti Sebagian Pasir

2026-02-09T02:15:42+00:00

Glass waste is a non-biodegradable material, so it must be processed or reused. Using glass waste as a substitute for sand in concrete can be an alternative use of glass waste. Furthermore, glass also contains silica (SiO2), which acts as a pozzolan that binds, making it suitable for use as a concrete mixture. The use of glass waste as a sand substitute is crucial for achieving a gradation that meets the requirements. This study used a concrete compression strength of 25 MPa. The percentage of sand substituted by glass waste was 0%, 7.5%, 10%, 12.5%, and 15%. The concrete volumetric weight increased proportionally with the increase in the glass waste percentage. This indicates that the use of glass waste increases the concrete density. This density is correlated with the concrete compressive strength. The results of the test analysis showed that the increase in volumetric weight was proportional to the increase in concrete compressive strength. This indicates that glass waste material has good fine aggregate properties and can be used as a partial sand replacement. This is because the glass waste material has a gradation that meets the requirements and contains silica which has pozzolanic properties so it can bind.

Implementasi Smart Apps Creator dalam Pengembangan Media Pembelajaran Informatika Berbasis Android

2026-02-09T02:30:50+00:00

Informatics subjects at SMK Negeri 1 Paguyaman still largely use conventional learning media, such as printed books, worksheets, and PowerPoint slides, which cannot provide an interactive and engaging learning experience. This condition has an impact on low student interest, participation, and understanding of the material. Therefore, this study was conducted with the aim of implementing a smart app creator in designing and developing Android-based interactive learning media as a more effective, engaging, and easily accessible learning solution. This study used the Research and Development (R&D) method with a 4D development model that includes the Define, Design, Develop, and Disseminate stages. The developed media is equipped with interactive features such as visual materials, quizzes, and educational games tailored to the characteristics of vocational school students. The validation results showed that the media obtained an average score of 138 from material experts, 106.5 from media experts, and 101 from student assessments, all of which are included in the "Very Feasible" category. Based on these results, the developed learning media is declared feasible for use to improve the quality of Informatics learning. In addition, this media is also able to provide a more active, interactive, and interesting learning experience for students.

Implementasi FMEA dan Perbaikan Tata Letak untuk Meningkatkan Produktivitas pada Departemen Dempul Painting di PT XYZ

2026-02-09T03:03:34+00:00

PT XYZ, a bus body manufacturing company, faces a high defect rate in the Putty and Painting Department, recording a total of 3,697 defects from January to October 2023, with the peak occurring in April at 521 cases (14.1%). The dominant defects include discoloration, overspray, waviness, and damage to the clear coat and putty, indicating a systemic issue. This study aims to identify major defects and determine improvement priorities using the Operation Process Chart, 8 Waste questionnaire, and Failure Mode and Effect Analysis (FMEA) based on the Risk Priority Number (RPN). Results show that the basecoat process has the highest RPN value of 80, while the baggage paint process has the lowest at 12. The main causes include overproduction, long workstation distances, excessive waiting time, unstable raw materials, lack of operator training, and weak inspection systems. Recommended improvements include SOP standardization, layout optimization, regular training, temperature and lighting control, and strengthening quality control to enhance product quality and production efficiency.

Comparative Analysis of Columns Ratio on Structural Performance and Cost Efficiency

2026-02-09T04:26:48+00:00

Planning is crucial in construction as it can significantly reduce costs by aligning structural design with requirements while minimizing excess. This study evaluates the structural performance of columns with different shapes and dimensions, utilizing data from the construction site and Indonesian National Standards (SNI). The analysis reveals that square-shaped columns, with a cross-section ratio close to 1, require less material than rectangular columns, with a 17.35% lower concrete volume and a 23.37% smaller formwork area. However, the reinforcement needed for square columns is 6.38% higher. Overall, square columns lead to a 15.42% reduction in production costs. This also results in lower cement consumption, contributing to decreased CO₂ emissions—Design B using 856.32 kg (18.52%) less cement than Design A. The results support the principles of the Sustainable Development Goals (SDGs), particularly SDG 9 (Industry, Innovation, and Infrastructure), SDG 11 (Sustainable Cities and Communities), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action). These findings align with the Sustainable Development Goals (SDGs), emphasizing the importance of sustainability alongside cost efficiency in structural planning.

Eksperimental Beton Ringan Struktural dengan Inovasi Serat Polypropylene sebagai Pengendali Retak

2026-02-09T04:49:58+00:00

This study aims to evaluate the effect of polypropylene fiber addition on the mechanical properties and crack behavior of structural lightweight concrete using local aggregates from Bali. The research was conducted experimentally by preparing cylindrical specimens (Ø150 × 300 mm) and beam specimens (200 × 200 × 2000 mm). Polypropylene fiber was added at 0% and 0.6% by volume of concrete, with superplasticizer SIKA ViscoCrete-3115 N included to maintain workability. The results show that the addition of polypropylene fibers had no significant effect on the concrete density, which remained below 1900 kg/m³, meeting the structural lightweight concrete criteria of ACI 213R-14. The compressive strength of the fiber-reinforced concrete decreased slightly by about 11.4% compared to the control mix, while the splitting tensile strength increased by 7.5% and the flexural strength increased by 9.9%. The maximum crack width decreased from 0.85 mm to 0.55 mm, indicating that the fibers effectively controlled crack propagation and improved ductility. Overall, the incorporation of 0.6% polypropylene fibers enhanced the crack resistance and toughness of structural lightweight concrete without compromising its low density, making it a promising material for lightweight structural elements in multi-story and prestressed concrete applications.

Pemanfaatan Assemblr Edu dalam Pembelajaran Simulasi Komputer: Pengaruhnya terhadap Minat Belajar Siswa

2026-02-09T04:56:39+00:00

In the educational process, there are various factors that influence the success of the learning process, one of which is student interest in learning. However, in practice, there are still a number of problems related to low student interest in learning. One of the causes is the lack of interesting learning media and abstract learning materials, which cause students to lose interest and feel bored in learning. This situation has an impact on low student interest in learning. This study aims to examine the effect of Assemblr Edu-based learning media on students' interest in learning, particularly in Von Neumann computer simulation material. The media validation results showed a percentage of 88%, indicating that Assemblr Edu-based learning media is suitable for use. Additionally, the hypothesis test using the independent samples t-test method yielded a Sig value of 0.009 < 0.05, where the result is smaller than Sig 0.05, meaning there is an effect on students' interest in learning. This finding indicates that Assemblr Edu-based learning media influences students' interest in learning.