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Utilization of Corn Cob Waste as an Alternative Catalyst in Catalytic Converters for Diesel Engine Carbon Emission Reduction Muhajir Muhamad; Imron Musthofa; Hajar Isworo; Muhammad Rezki Fitri Putra; Bayu Agung Wicaksono
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 25 No. 3 (2025): November
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v25i3.140-146

Abstract

Catalytic converters function to transform harmful exhaust gases into less hazardous substances through catalytic reactions, primarily oxidation and reduction. This study aims to investigate the potential of corncob waste as an alternative catalytic material in catalytic converters for reducing carbon emissions from diesel engines. The methodology involves synthesizing biochar-based catalysts derived from corncobs via pyrolysis, followed by performance evaluation within a catalytic converter system under varying engine speeds: 700 RPM, 900 RPM, and 1100 RPM. Experimental results demonstrate that catalytic efficiency does not increase monotonically with char content; instead, the 70% char formulation achieved the highest smoke opacity reduction, recording 18.90% at 700 RPM and 14.70% at 900 RPM, outperforming both the 50% and 100% variants at 1100 RPM, where exhaust temperature and flow rate increase substantially, the 100% char catalyst showed comparatively greater stability, achieving a reduction of 5.50%, while the 70% formulation declined to 2.90%. These quantitative outcomes confirm that optimal performance arises from a balanced char loading that maximizes reactive surface area while preserving gas–solid interaction efficiency. Corncob biochar thus represents a viable and sustainable alternative to metal-based catalysts. However, the variability in performance across operating conditions and the need for improved thermal durability underscore the importance of further material optimization for commercial diesel applications.
Eksplorasi Etnomatematika pada Tugu Hari Jadi Kabupaten Dati II Tanah Laut Dewi Indra Anggraeni; Bayu Agung Wicaksono; Liny Mardhiyatirrahmah
Mandalika Mathematics and Educations Journal Vol 7 No 4 (2025): Desember
Publisher : FKIP Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jm.v7i4.10802

Abstract

This study explores the ethnomathematics embedded in the architecture of the Tugu Hari Jadi Kabupaten Dati II Tanah Laut, addressing the persistent issue of low mathematical literacy among Indonesian students in PISA assessments. The research emphasizes the urgent need for culturally relevant pedagogy to make mathematics less abstract and more engaging, particularly given the lack of existing ethnomathematical studies focusing on specific monuments like this one. The primary objective was to identify the inherent mathematical elements within the monument's design and determine their educational applicability. Utilizing a qualitative ethnographic approach, the research successfully catalogued concepts from both plane geometry (rectangles, circles, octagons) and solid geometry (octagonal prisms, cylinders, and hemispheres), complete with their respective mathematical formulas for area, perimeter, and volume calculations, and the role of trigonometry. The findings offer a strong ethnomathematical interpretation, revealing the monument as a cultural artifact that harmoniously symbolizes local values such as balance, steadfastness, and divinity. Educationally, the monument serves as an authentic learning resource to visualize complex geometry, thereby providing valuable contextual material to increase student interest, motivation, and critical mathematical literacy skills in line with global standards.