INVOTEK: Jurnal Inovasi Vokasional dan Teknologi

Application of Calcined Green Mussel Shell Powder to Increase Peat Soil Stability Against CBR Values as a Road Pavement Subgrade

2026-05-26T06:49:00+00:00

Peat soil has compressible properties, high water content, and low bearing capacity, so it needs to be stabilized to increase its strength as a road pavement subgrade. Peat soil is commonly found in South Sumatra, especially in the Banyuasin II District, Banyuasin Regency, South Sumatera. This study added green mussel shell powder (CaCO₃) and calcined mussel shell powder (CaO) as stabilizers with the CBR (California Bearing Ratio) testing method. This test was carried out with variations in the mixture of mussel shell powder (0%, 10%, 20%, 30%) and curing time (0, 3, 7 days), as well as testing physical and mechanical properties such as atterberg limits, specific gravity, sieve analysis, soaked CBR, and unsoaked CBR. Samples with optimal CBR values will be added with CaO (calcined mussel shell powder) 10% to see its effect. Based on the test results, the original peat soil has an unsoaked CBR of 0.65% and a soaked CBR of 0.65%. After the stabilizer was mixed, the optimal variation was found in a mixture of peat soil plus 30% shell powder with 7 days of curing at 13.7%, while for soaked CBR, with a variation of 30% soaking for 4 days at 8.5%. Furthermore, this variation was mixed with calcined shell powder (10%) to see its effect. The test results showed a significant change, the values of unsoaked CBR 35% and soaked CBR 45%.

Virtual Reality in Experiential Learning Models to Develop Students' Computational Thinking: A Systematic Literature Review

2026-07-22T02:18:57+00:00

Computer network learning in vocational schools is considered difficult because the material is abstract. This often causing confusion for students when solving problems systematically. Based on these problems, this study aims to systematically review and synthesize evidence regarding the effectiveness of Virtual Reality (VR) integrated with the Experiential Learning (EL) Kolb model in developing Computational Thinking (CT) abilities. Using the Systematic Literature Review (SLR) method and PRISMA protocol. we analyzed 26 selected articles from 2,479 initial results (search on May 26, 2026). The results indicate that immersion-based VR serves as a real simulator, providing a Concrete Experience and facilitating Active Experimentation through hands-on practice. For school with limited VR devices in schools, collaborative learning methods are an effective alternative solution. This approach strengthens group memory, which effectively fulfills the Reflective Observation stage in Kolb's theory. Furthermore, manipulating digital objects in VR supports Abstract Conceptualization, helping students stimulate pillars of decomposition, abstraction, and algorithmic reasoning. In conclusion, this study analyze the trends and development in current research to demonstrate how the collaboration between VR and EL models offers a new scientific contribution. These findings provide a clear guide for teachers and curriculum developers to design more effective teaching strategies in vocational schools.

Stakeholder Perceptions of Collaborative Project-Based USP for Vocational Summative Assessment

2026-07-06T04:42:32+00:00

This study describes the stakeholder perceptions of collaborative project-based Educational Unit Exam (USP: Ujian Satuan Pendidikan) implementation as a summative assessment innovation in a vocational high school. The novelty of this study lies in conceptualizing the Educational Unit Examination (USP) as a school-level summative assessment architecture rather than merely a final written examination. The proposed model integrates authentic assessment, interdisciplinary project collaboration, competency-based assessment, workplace relevance, and individual accountability within a single assessment framework. A descriptive quantitative survey was conducted at Vocational High School 1 Anyer involving 318 purposively selected respondents: 286 twelfth-grade students, 25 subject teachers, five school management members, and two education-office stakeholders. Data were collected through Likert-scale questionnaires consisting of 20 statement for each respondent group and analyzed using descriptive statistics based on the percentage of positive responses for each stakeholder group. The results show positive stakeholder perceptions: school management reported 90%, education-office stakeholders 89%, students 82%, and teachers 73%. These findings suggest that stakeholders perceived the collaborative project-based USP as supporting interdisciplinary collaboration, authentic competency demonstration, and stronger alignment between school assessment and workplace-oriented learning. However, the study is limited to perception data from one school, uses aggregate percentages, and does not include objective performance indicators, item-level reliability evidence, or construct validation. Therefore, the findings should be interpreted as stakeholders perceptions rather than evidence of actual effectiveness. Practically, sustainable implementation requires structured assessment rubrics, evidence of individual contribution, portfolio documentation, individual oral questioning, teacher moderation, and workload management.

Effect of Reactor Temperature on the Characteristics of Alternative Fuel Produced from the Pyrolysis of Mixed Plastic Waste

2026-07-16T07:33:19+00:00

Plastic waste is a type of waste that is difficult to decompose, and its quantity continues to increase, potentially causing environmental problems. One method that can be applied to reduce plastic waste is pyrolysis, a thermal decomposition process without oxygen that produces pyrolysis oil, which has the potential to be used as an alternative fuel. Reactor temperature is an important factor that influences the thermal decomposition process, thus affecting the characteristics of the resulting pyrolysis oil. This study aims to analyze the effect of reactor temperature on the characteristics of pyrolysis oil produced from mixed plastic waste. The study was conducted experimentally using 5 kg of mixed non-chlorinated plastic waste in each test, with reactor temperature variations of 300 °C, 320 °C, 340 °C, 360 °C, and 380 °C. Each temperature variation was tested once. The parameters analyzed included operating time, density, viscosity, and calorific value. The results showed that increasing the reactor temperature accelerated the operating time from 70 minutes at 300 °C to 50 minutes at 380 °C. The density of pyrolysis oil ranged from 745.18 to 785.15 kg/m³, with a viscosity of 4.793 to 5.891 cSt and a calorific value of 38.681 to 40.405 MJ/kg. At 380 °C, the highest calorific value of 40.405 MJ/kg was achieved, while the density and viscosity remained within ranges close to those of conventional fuels. Therefore, 380 °C exhibited the best pyrolysis oil characteristics among the temperature variations studied and has greater potential for development as an alternative fuel after further processing and purification.