Jurnal Pendidikan Teknik Mesin starting in 2024 migrates to better secure from various unwanted things, including journal hacking and so on. To submit, the author please visit the new website page of our journal at the link https://journal.unnes.ac.id/journals/jptm MIGRATION OFFICIAL STATEMENT HERE P-ISSN 2503-1759 | E-ISSN 2503-1759 First published in June 2001 and since then it is published biannually in June and December. Contains articles lifted from the results of research on field mechanical engineering and the idea of thinking (conceptual) for the development of education and teaching in the field of Mechanical Engineering, in particular at the Institute of Education Personnel (LPTK) and Vocational High School (SMK). The journal is also a means of communication between professors, teachers, instructors, practitioners in business / industry, as well as other related institutions. JPTM Indexed by: DIMENSION | SINTA | GARUDA
A REVIEW ON THE POTENTIAL OF INDONESIAN NATURAL FIBERS AS BALLISTIC COMPOSITE MATERIALS
Ballistic composites are key materials in protective applications designed to absorb and dissipate the impact energy of projectiles. Currently, the reliance on synthetic materials such as aramid fibers (Kevlar) and ultra-high molecular weight polyethylene (UHMWPE) faces challenges including high production costs, environmental impact, and import dependency. Indonesia, with its abundant natural fiber resources such as ramie, abaca, bamboo, and sisal, has great potential to develop sustainable and self-reliant ballistic composite materials. This review aims to systematically examine the potential of Indonesian natural fibers as ballistic composite materials by analyzing their mechanical properties, comparing them with ballistic requirements, and identifying key challenges and development strategies. The study concludes that although natural fibers exhibit promising mechanical properties, they face major limitations such as hydrophilic nature and variability in characteristics. However, chemical treatments and surface engineering (such as reinforcement with SiO₂, CNT, or SiC) have been shown to improve fiber–matrix interfacial performance, thereby opening opportunities for the utilization of Indonesian natural fibers in effective and environmentally friendly ballistic composites.
Copyright (c) 2026 Jurnal Pendidikan Teknik Mesin
The Effect of Fuel Injection Duration on Exaust Gas Emissions of a 4-Stroke Engine 113.68 CC Using Bioethanol Fuel
In Indonesia, the number of motor vehicles using fuel as an energy source is rising quickly. The government has developed renewable energy to reduce fuel consumption because, according to the Downstream Oil and Gas Regulatory Agency (BPH Migas), the consumption of gasoline-type fuels in 2017 was 1,858,875 L/Quarter. Determining the impact of using bioethanol with different injection times on exhaust gas emissions was the aim of this study. Bioethanol is an environmentally friendly alternative fuel for cars that uses less fuel. It is a renewable energy source made from vegetable sources. Variations in fuel injection duration and exhaust gas emission are the main subjects of this study. With no modifications to compression, the engine operates under standard conditions. A gas analyzer and engine speeds of 1500, 2000, 3000, 4000, and 5000 Rpm were used in the study. According to the study's findings, the amount of CO exhaust gas dropped. At 5000 RPM for 4 ms, the lowest CO in bioethanol fuel is 1.21%. With bioethanol fuel, the amount of HC exhaust gas emissions has dropped. 710 ppm at 3000 Rpm for 4 ms is the lowest HC level. When using bioethanol as fuel, the amount of CO2 emissions rises. The maximum CO2 concentration is 6.50% at 5000 RPM for 4 ms. The maximum amount of O2 emissions from bioethanol fuel is recorded at 1500 RPM for 4 ms.
ANALYSIS OF MECHANICAL CHARACTERISTICS OF TOOTH BUCKET EXCAVATOR BASED ON DIFFERENT GRADE LEVELS
The purpose of this study is to comprehend the microstructure and hardness value of three distinct tooth bucket manufacturers. Three manufacturers' excavator tooth buckets—Canada Grade, China Grade A, and China Grade C—are compared for their mechanical characteristics. Among the tests are the Vickers method for measuring hardness, optical microscopy for examining microstructure, and chemical composition analysis. According to the results, the primary elements in all three specimens—carbon, silicon, manganese, and chromium—meet the DIN Grade 25CrMo4 standard. The martensite phase, which gives the Canada product its hardness and resistance to deformation, dominates its microstructure. The China Grade C product, on the other hand, has a more prominent ferrite phase, which raises ductility while decreasing hardness. China Grade C (570.24 HVN) had the highest hardness test value, followed by China Grade A (517.67 HVN) and Canada (468.09 HVN). This demonstrates that while Canada excels at withstanding heavy loads without damage, China Grade C is better suited for applications needing high wear resistance. Users of heavy machinery can use this study as a scientific guide when choosing bucket nails based on operational requirements, including material toughness and wear.
tooth bucket, vickers hardness, microstructure, martensite phase, ferrite phase.
Application of MULTIMEDIA Powerpoint Assisted Learning to Improve Learning Outcomes of Knowledge of the function of Fracture Machine Parts
The purpose of the research conducted to determine the effect of using PowerPoint multimedia on improving student learning outcomes in the subject of milling machine parts at SMK IPT Karangpanas. The background of this research is based on poor student learning outcomes, which are below the Graduation Threshold Value (KKM). Before conducting research, the feasibility of media and material was tested by experts with a percentage of 83% so that the material and media were suitable for use. The method used is quantitative experimental research with a two-group pre-test and post-test experimental model. Samples from two XI classes were taken randomly, with one experimental class and the other as a control class. Data were collected through questions in the form of pretest and posttest, and analysed using normality test, paired sample t-test, independent sample t-test, and N-Gain analysis. Results showed a significant improvement in learning outcomes in the experimental class compared to the control class, with a higher mean posttest score. The independent sample t-test showed significance <0.001, and the mean N-Gain of 0.4713 was classified as moderate. Thus, the use of PowerPoint multimedia was proven effective in improving students' learning outcomes.
The Use of E-Modules to Enhance Students’ Cognitive Achievement in Understanding Milling Machine Components
Penelitian ini bertujuan untuk mengembangkan dan mengevaluasi keefektifan e-modul interaktif sebagai media pembelajaran untuk meningkatkan hasil belajar kognitif siswa pada pokok bahasan komponen mesin frais. Penelitian ini menggunakan metode Research and Development (R&D) dengan model pengembangan 4D (Define, Design, Develop, dan Disseminate). Subjek penelitian adalah siswa kelas XI Program Studi Teknik Pemesinan SMK Negeri 5 Semarang. Instrumen pengumpulan data meliputi soal pretest dan posttest, lembar validasi ahli materi dan media, serta angket respon siswa. Hasil validasi menunjukkan bahwa e-modul sangat layak digunakan dalam proses pembelajaran. Hasil uji coba menunjukkan adanya peningkatan hasil belajar siswa yang signifikan setelah menggunakan e-modul, dibuktikan dengan selisih skor pretest dan posttest yang dianalisis menggunakan uji-t. Rata-rata skor N-Gain menunjukkan adanya peningkatan yang cukup. Selain itu, respon siswa terhadap penggunaan e-modul tergolong sangat positif. Oleh karena itu, e-modul dianggap efektif sebagai media pembelajaran interaktif untuk meningkatkan pemahaman siswa tentang komponen mesin frais. Penelitian ini merekomendasikan penggunaan e-modul sebagai alternatif inovatif dalam pembelajaran berbasis teknologi dalam pendidikan kejuruan.
module, milling machine, cognitive learning, instructional media development, R&D
Copyright (c) 2025 Jurnal Pendidikan Teknik Mesin
UTILIZING E-MODULES TO ENHANCE STUDENTS’ ACHIEVEMENT IN UNDERSTANDING SMAW WELDING DEFECT ANALYSIS AT SMK N 5 SEMARANG
Understanding welding defect analysis is a crucial competency in vocational welding education, especially in ensuring the quality and safety of welding outcomes. However, many students struggle to master this material due to the lack of interactive and adaptive learning media. This study aims to develop and implement an electronic module (e-module) to enhance student learning outcomes in Shielded Metal Arc Welding (SMAW) defect analysis at SMK N 5 Semarang. The research uses a Research and Development (R&D) approach based on the 4D model: Define, Design, Develop, and Disseminate. A one-group pre-test post-test design was used, involving 33 Grade XI Mechanical Engineering 2 students. The e-module was validated by experts and classified as "Valid" in terms of content, media, and assessments. Students' average scores increased from 40.61 in the pre-test to 78.64 in the post-test. Statistical analysis using the Wilcoxon Signed-Rank Test and paired t-test showed a significant difference (p < 0.001). The average N-Gain score was 0.63, indicating a moderate improvement. The results confirm that the e-module is both feasible and effective. It enhances students’ conceptual understanding and supports independent, technology-based learning aligned with the characteristics of digital-native learners.
ANALYSIS OF THE APPLICATION OF GAME BASE LEARNING IN VOCATIONAL EDUCATION OF LATHE MACHINING
This article examines the implementation of the Game-Based Learning (GBL) model in lathe machining education at vocational high schools (SMK). Lathe machining is a manufacturing process that produces cylindrical machine components using a lathe, in which the workpiece rotates and is subjected to a single-point cutting tool aligned with the workpiece axis. To improve the quality of lathe machining education, an effective instructional model such as Game-Based Learning is needed. This research applies a Systematic Literature Review (SLR) approach to identify and analyze six relevant studies published between 2020 and 2025 based on inclusion criteria. The findings show that GBL has a positive impact on increasing students’ learning motivation, engagement, and learning outcomes in lathe machining practice. The study concludes that GBL is an effective solution for practice-based learning in vocational education and recommends its wider adoption in technical vocational training.
THE EFFECTIVENESS OF LEARNING MEDIA BASED ON YOUTUBE VIDEO TUTORIALS ON STUDENT LEARNING OUTCOMES PER WELDING PRACTICE
This study aims to analyze the effectiveness of YouTube-based video tutorial learning media in improving students' cognitive learning outcomes in Shielded Metal Arc Welding SMAW practice at SMK Negeri 4 Semarang. The background of this research is based on the limited use of contextual and engaging instructional media in vocational education, which leads to low conceptual understanding and applied skills among students. The research employed a quasi-experimental method with a pretest-posttest control group design. The sample consisted of 60 tenth-grade students from the Mechanical Engineering Expertise Program, selected through purposive sampling and divided into two groups: an experimental group that used YouTube-based instructional videos and a control group that applied conventional lecture methods. The research instrument comprised 20 validated multiple-choice questions. Data was analyzed using the Shapiro-Wilk normality test, Levene's homogeneity test, independent t-test, and N-Gain analysis to assess learning improvement. The results indicated a significant difference between the experimental and control groups p< 0.001, with the experimental group achieving an average post-test score of 84.50 and an N-Gain of 0.6100 high category. In contrast, the control group scored an average of 75.33 with an N-Gain of 0.4155 medium category. These findings suggest that using YouTube video tutorials as instructional media effectively enhances students' learning outcomes in welding practice while also creating a more contextual, visual, and student-centred learning process suited to the learning styles of vocational students.
DEVELOPMENT OF MOTORCYCLE TUNE UP TUTORIAL VIDEO MEDIA FOR GRADE X STUDENTS OF MOTORCYCLE TECHNIQUE AND BUSINESS EXPERTISE COMPETENCY AT SMK MUHAMMADIYAH BAWANG
This study aims to develop learning media in the form of a video tutorial on motorcycle tune-up practices for class X students of Motorcycle Engineering and Business Expertise at SMK Muhammadiyah Bawang. The method used is research and development (R&D) by adapting the Borg & Gall model to the final product trial stage. Data collection was carried out through observation, interviews, expert validation questionnaires, student response questionnaires, and practical skills tests. The results of the study showed that the video tutorial media developed obtained the category "feasible" to "very feasible" from the material and media aspects, and received a positive response from students. The use of video tutorials has proven effective in improving students' understanding of concepts and practical skills, as well as supporting student-based learning approaches. This study contributes to the development of digital-based learning media in vocational education environments.
THE IMPACT OF QUALITY, VISIONARY, AND ENTREPRENEURIAL LEADERSHIP OF VOCATIONAL SCHOOL PRINCIPALS ON THE SUCCESS OF SCHOOL MANAGEMENT
This study investigates the influence of school principals’ leadership styles, specifically quality leadership, visionary leadership, and entrepreneurial leadership, on the success of school management in Vocational Schools specialising in Technology and Engineering in Yogyakarta. Employing a descriptive quantitative approach with an ex-post facto design, data were gathered from 282 teachers selected through cluster sampling and stratified random sampling across 16 Vocational schools of various accreditation levels. The results reveal significant positive influences of quality leadership (31.5%), visionary leadership (11.1%), and entrepreneurial leadership (35.7%) on school management success. Simultaneously, the combined leadership styles contributed 37.3% to the variance in management success. These findings highlight the importance of multifaceted leadership in improving educational outcomes and suggest the need for policy reinforcement to support effective school governance.
school leadership, quality leadership, visionary leadership, entrepreneurial leadership, school management.
ANALYSIS OF EXHAUST EMISSIONS, NOISE, AND PERFORMANCE OF A 110CC MOTORCYCLE USING A PERFORATED-CLOSE CONICAL SILENCER MUFFLER
This paper analyzes the exhaust emission, noise, and performance of 110cc motorcycles experimentally through PCCS exhausts compared to standard exhausts. This study adopts an experimental method involving three tests: exhaust emission testing based on the SNI 09-7118.1-2005 standard, noise measurement using the static test procedure according to the UN-R 41-04 standard, and performance evaluation conducted with an inertial dynamometer. Implementing the PCCS exhaust system on a 110 cc automatic motorcycle positively impacts exhaust emissions, noise levels, and engine performance. Compared to the standard exhaust, the PCCS significantly reduces CO and HC emissions by 78.99% and 55.99%, respectively, while maintaining noise levels within regulatory limits in urban conditions. In terms of performance, the PCCS delivers higher torque and power output, particularly in the 3500–5500 RPM range, which aligns with typical riding conditions. These improvements are attributed to the system’s efficient exhaust flow and reduced backpressure. The PCCS exhaust presents a promising solution for enhancing environmental sustainability, performance, and rider comfort in small-displacement motorcycles.
ENHANCING STUDENT CREATIVITY IN CNC COURSES THROUGH MARKETPLACE-BASED TEACHING FACTORY: A CLASSROOM ACTION RESEARCH
The rapid transformation brought by Industry 4.0 and Society 5.0 demands vocational education to produce graduates who are not only technically competent but also creative and entrepreneurial. This study aims to enhance student creativity in CNC (Computerized Numerical Control) learning by implementing a marketplace-based Teaching Factory model. Using a Classroom Action Research (CAR) design, the study involved 20 students of the Mechanical Engineering Education Program over two learning cycles. Each cycle included planning, implementation, observation, and reflection stages. The results showed significant improvements across four assessed aspects: technical skills (from 74.1 to 86.6), product design (from 75.1 to 87.9), marketing (from 73.5 to 86.5), and reflective learning (from 78.2 to 91.0). The marketing aspect experienced the highest gain, indicating that digital marketplaces provide an effective platform for practical entrepreneurial learning. This study concludes that integrating marketplace platforms into Teaching Factory learning can significantly foster creativity and entrepreneurial skills in vocational students.
DESIGN OF DRYER FOR SMALL FARMERS BASED ON THE STUDY OF ERGONOMICS THERMAL ENGINEERING APPLICATION
Ergonomics thermal engineering combines the principles of thermal engineering and ergonomics to design systems and products that optimize energy and resources, improve worker thermal comfort, and reduce thermal stress and fatigue. Small farmers still dry post-harvest food under direct sunlight in open areas. This process produces less than optimal drying thermal temperatures, which impacts long drying times, and dried food is susceptible to dust and animal faeces exposure. In addition, exposure to sunlight on workers causes additional workloads that affect fatigue. This can be overcome by utilizing solar collectors through dryer design based on anthropometric data of workers as users. The dryer was designed through an ergonomics thermal engineering study. Based on anthropometric data and percentile calculations, dimensions were obtained for the dryer design, such as the bottom shelf with a height from the floor of 66.88 cm based on the knuckle, the top shelf height of 123.8 cm from the floor based on standing eye height, and the height of the drying room air chimney from the floor is 177.59 cm based on the height of the upper reach. To avoid new problems with the dryer application, a table was designed as a workaid with a height of 84.31 cm based on the height of the standing elbow. Applying the principles of ergonomics thermal engineering can create systems and products that are more comfortable, safe, and efficient for workers.
EFFECT OF WELDING CURRENT ON LOW CARBON STEEL CHARACTERISTICS IN SMAW CLADDING PROCESS
The electric current magnitude is a fundamental parameter that directly affects penetration characteristics and weld bead geometry. This study analyzes the effect of current variations on physical and mechanical properties in the cladding process using the Shielded Metal Arc Welding (SMAW) method. The materials used are low-carbon steel and HV-600 electrodes with a diameter of 3.2 mm. The SMAW method was applied with current variations of 100 A, 120 A, 140 A, and 160 A. The tests carried out were NDT liquid penetrant, macro structure, micro structure and Vickers hardness. The results indicate a positive correlation between increasing current and hardness values in the weld area, with the highest hardness recorded at 665.803 HVN at 160 A and the lowest at 515.143 HVN at 100 A. Meanwhile, in the Heat Affected Zone (HAZ), a non-linear pattern was observed, with a maximum hardness of 263.237 HVN at 120 A and a minimum of 219.110 HVN at 140 A. Microstructural analysis revealed the formation of ferrite, pearlite, bainite, and martensite phases in the weld area, providing insights into optimizing welding parameters to enhance the mechanical properties of low-carbon steel cladding.
ERGO-MECHANICAL APPLICATIONS IN SMALL-SCALE SMAW WELDING TABLE DESIGN
SMAW (shielded metal arc welding) is widely used in almost all types of welding work, including small industries. In small industries, workers doing SMAW welding work are generally done by squatting. This work posture causes musculoskeletal complaints in workers as a result of unnatural work postures. To overcome this is done through ergo-mechanical applications to create aids in the form of welding tables. Ergonomically based on worker anthropometric data, while mechanically with the selection of strong, lightweight, and affordable materials in terms of cost. The results of testing the welding table design based on ergo-mechanical applications provided a decrease in musculoskeletal disorders in workers. Workers' musculoskeletal disorders can be reduced by 24.61%. From the moderate category, an average of 51.6, to the light category, with an average of 38.9. The ergo-mechanical application will produce work tools that are comfortable for workers to use and meet technical standards related to specifications as a description of the technical characteristics of a work tool.
Copyright (c) 2024 Jurnal Pendidikan Teknik Mesin
EFFECT OF VARIATION IMMERSION TIME FIBER HEMP COMPOSITE USING NaOH MATRIX POLYURETHANE ON TENSILE STRENGTH METHOD
NaOH immersion treatment on hemp fiber is very important in making composites. This is because natural fibers still contain materials such as lignin and hemicellulose so hemp fibers are cleaner and can provide strong fiber and resin attachment. The aim of this research is to find out how the best time for soaking in NaOH for hemp fiber compares to the tensile strength of hemp fiber composites. The materials used are polyurethane and hemp fiber. The research focused on variations without treatment, 2 hours, 3 hours, 4 hours, and 5 hours with a percentage of 5% NaOH and dried under direct sunlight after soaking. Composite manufacture was carried out using the compression molding method for 24 hours with a pressure of 5 bar. Tensile testing was also used in this research with reference to the ASTM D 638 standard. The fiber surface experiences changes in shape such as cleanliness, color and fiber structure which are different in each variation. It should be noted that the maximum tensile strength is 11,597 MPa at 4 hours of immersion, and the lowest tensile strength is 6,054 MPa at 5 hours of immersion. Then the lowest modulus of elasticity value is found in the variation without treatment at 0,049 GPa. The highest value of elastic modulus is found in the 4 hour variation with a value of 0,076 GPa.
DEVELOPING ANALOG AND DIGITAL ELECTRONIC MEDIA KITS FOR AUTOMOTIVE ENGINEERING EDUCATION STUDENTS
Instructional media has an important function for facilitating academia to achieve the learning objectives. Therefore, this study aims to develop an instructional media of the analog and digital electronics for automotive engineering education students. This study used a research and development method which consisting of 4D steps (define, design, development, and dissemination). The instructional media feasibility assessment from the lecturers and students was obtained using a questionaire. The lectures and students, after assessing the media kits, both were suggested that it has a good lay out, appropriate with the learning outcomes, and feasible for benefitting university learners in analog and digital electronics course especially in practice courses. The implementation of this analog and digital electronic media improves the students achievement in the basic analog and digital automotive electronics courses
analog and digital electronics, automotive, instructional media, learning objective, practice
EFFECT OF PREHEATING TEMPERATURE VARIATION ON MICROSTRUCTURE AND HARDNESS OF WELD OVERLAY CLADDING OF SS400 CARBON STEEL BY SMAW METHOD
SS400 carbon steel is a type of low carbon steel that has low surface hardness, wears easily, and is not resistant to impact. The application of cladding can reduce the risk of material failure due to the weakness of SS400 carbon steel. In this study, cladding was performed by SMAW method using HV-600 electrodes and a current of 115 A. This welding process causes heat to be concentrated in the melting area, resulting in uneven heating and cooling, so preheating is necessary. This study aims to evaluate the effect of preheating temperature variations of 200°C, 300°C, 400°C, and non-preheating on microstructure and hardness in the cladding process. Macro structural testing shows that the application of preheating can minimize the occurrence of welding defects, and an increase in preheating has an effect on increasing the depth of the HAZ in each specimen tested. Microstructure testing shows that the application of higher preheating will form more ductile phases in the base metal, diffusion layer, HAZ areas. The base metal area has pearlite and ferrite phases. The diffusion layer shows clear boundaries as a result of the diffusion process. The HAZ section forms a fine pearlite microstructure and coarse pearlite and ferrite phases. The weld metal layer is not affected by the preheating temperature used, there are martensite and ferrite phases. Hardness testing on 200oC preheating specimens has the highest hardness in the weld metal of 680.11 HV. Hardness in the diffusion layer, HAZ, and base metal which shows that an increase in preheating temperature affects the decrease in the hardness value of the specimen.
THE EFFECT OF VARIATIONS IN CURING TEMPERATURE OF CARBON FIBER/PVC FOAM BOARD SANDWICH COMPOSITES ON BENDING TEST FAILURE ANALYSIS
Curing is a method to improve the ability of sandwich composite materials by heating the sandwich composite in an electric oven for a certain time and temperature. This research aims to observe and analyze the effect of curing temperature on bending strength and elastic modulus as well as analyzing the fracture results of sandwich composites. The materials used are polyester resin, 240 gsm twill carbon fiber and PVC foam core with a thickness of 5 mm. The manufacturing method used is vacuum bagging and the curing process is carried out with temperature variations of 70°C, 80°C and without curing for 1 hour. The test carried out is a bending test using the ASTM C393 standard. The maximum bending strength value of the sandwich composite is found at a curing temperature of 80°C, namely 48.35 MPa, while the lowest bending strength value is found in the variation without curing, namely 30.07 MPa. The highest elastic modulus value is also found at a curing temperature of 80°C, namely 67.03 GPa and the lowest elastic modulus value is also found in the variation without curing, namely 33.67 GPa.
DEVELOPMENT OF LEARNING MEDIA FOR MOTORCYCLE ELECTRONIC FUEL INJECTION SYSTEM BASED ON FLIP HTML5 AT THE DEPARTMENT OF MOTORCYCLE ENGINEERINGAT SMK SUMBER DAYA BEKASI
The development of technology and information is very rapidly growing and influential in the world of education. Technology and information in learning are very helpful for educators in utilizing technology facilities to prepare for the learning process or when the learning process takes place. This study aims to develop Flip Html5-based e-book learning media for motorcycle Electronic Fuel Injection system material. This research uses the Research and Development (R&D) method using the 4D development model in its development, which must go through an expert assessment as a successful process of testing the feasibility of the developed product before it is later tested and used. The results of the feasibility test of Flip Html5-based e-book learning media get a percentage of 96.36% from material expert validators, 94.54% from media expert validators, and 89.23% from the results of the media feasibility test of 35 students. So, the results that have been carried out can be concluded that the Flip Html5-based e-book learning media for Motorcycle Electronic Fuel Injection system material developed in this study are "Very Feasible" to be used as a learning resource for students in learning.
motorcycle electronic fuel injection system
ANALYSIS OF THE EFFECT OF NaOH PERCENTAGE ON THE TENSILE STRENGTH OF SISAL FIBER (AGAVE SISALANA) AND POLYURETHANE COMPOSITES USING THE COMPRESSION MOLDING METHOD
The percentage of NaOH is one of the parameters that greatly affects the sisal fiber composite (Agave Sisalana). The purpose of this study was to observe and analyze the effect of the percentage of NaOH on the tensile strength of sisal fiber composites (Agave Sisalana). The materials used are sisal fiber (Agave Sisalana) and polyurethane resin at various percentages of NaOH, namely without treatment (0%), 4%, 7%, and 10% with soaking time for 2 hours and drying in the sun for a maximum of three days or until the fiber is completely dry. Composite manufacturing was carried out using the compression molding method for 24 hours at a pressure of 50 bar. The tests carried out in this study were tensile tests referring to the ASTM D 638 standard. The percentage of NaOH without treatment (0%) has the lowest maximum tensile value of 6.688 MPa, while the percentage of 7% NaOH has the highest maximum tensile strength value of 11.821 MPa. Then, the percentage of NaOH without treatment (0%) has the lowest maximum elastic modulus value of 0.072 GPa, and the highest maximum elastic modulus value of 0.152 GPa is also found at 7% NaOH percentage.
Interactive Learning Media Methods In The Field Of Mechanical Engineering: A Case Study Of Engineering Drawing Subjects
This study aims to find out whether the methods in interactive learning media that have been applied are appropriate or not. The application of interactive learning media methods to engineering drawing learning can improve learning efficiency, strengthen concept understanding and improve students' practical skills in mechanical engineering learning. This study uses a qualitative descriptive method with case studies as the main method. Data is collected through questionnaires and in-depth analysis so that it becomes a whole sentence as a whole. The results of the research that has been carried out show that the most effective learning model uses the practicum model in engineering drawing subjects. In addition, teaching aids also affect students' understanding of teaching materials in engineering drawing subjects. Thus, teachers must be able to make an interactive learning so that students understand the technical drawing material to the maximum.
Learning Media, Engineering Drawings, Interactive, Mechanical Engineering
THE EFFECT OF VARIATIONS IN THE DIAMETER AND NUMBER OF GROUNDSTRAP WINDINGS ON THE PERFORMANCE OF A 150 CC ENGINE
This research is a type of experimental research which aims to determine the effect of varying the diameter and number of groundstrap turns on the spark plug cable on power, torque, AFR and fuel consumption of a 150 CC motorbike engine. The results of the research show that there is a significant influence on engine power by using variations in the 0.3 mm diameter of the 260 winding groundstrap with an increase of 0.53 hp. When varying the diameter of 0.6 mm of winding 155 on power there is a significant influence with an increase of 0.52 HP and using a variation of 0.9 mm of winding 103 on power there is a positive influence with an increase of 0.43 HP. The use of groundstrap on engine torque with three types of variations increased by 1.03 Nm, 0.63 Nm and 0.75 Nm. There is no significant effect of using groundstrap on AFR. For the effect of using a groundstrap on fuel consumption, the variations with the most positive influence are the 0.3 mm diameter of the 260 winding and the 0.6 mm diameter of the 155 winding.
The Effectiveness Of Peer Teaching In Achieving Student Understanding In The Subject Of Milling Techniques
Education is one of the important human needs that cannot be separated in everyday life. Differences in individual understanding cannot be ignored at every level of human education. Therefore, teachers are required to design learning methods that are able to increase the effectiveness of the individual needs of learnersThe method used in designing this research is quasi experiment. the population in this study amounted to 36 students who were divided into two groups in one class at SMK Negeri 1 Nanggulan. The experimental design used is post test only control group design, which consists of a control class and an experimental class, each of which has a value. The average value on the understanding of the experimental class post-test results shows a value of 82.444 higher than the mean value of the control class. Nmax the experimental class showed 96.50 and Nmin of 72.50. Meanwhile, the Nmax of the control class showed 76.00 and Nmin of 64.00. The Pvalue of homogeneity (Levene's) >0.05 is 0.081 which indicates that the data is normally distributed. Then the normality test Pvalue results are below <0.05 which is 0.040 (experimental), 0.019 (control) by comparing the significance level Pvalue <0.05 then H0 is rejected and H1 is accepted. Peer teaching research proves that it is effective for improving student understanding in the subject of milling techniques of multilevel milling material.