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All Journal Journal of Mechanical Engineering Science and Technology JPSE (Journal of Physical Science and Engineering) CROP AGRO, Scientific Journal of Agronomy Jurnal Karinov Jurnal Engine: Energi, Manufaktur, dan Material Journal of Earth Energy Science, Engineering, and Technology Logic : Jurnal Rancang Bangun Dan Teknologi RING Mechanical Engineering
Muhajir, Muhamad
Politeknik Negeri Tanah Laut
Agriculture, Biological Sciences & Forestry Humanities Astronomy Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Social Sciences

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PENERAPAN MESIN ROL PIPA HIDROLIS PADA BENGKEL MODIFIKASI KONSTRUKSI MOTOR TRAIL Heru Suryanto; Aminnudin Aminnudin; Sukarni Aminnudin; Yanuar. R. A. Pradana; Reddy .A. Dharmabintara; Muhamad Muhajir; Fakris Muslim
Jurnal KARINOV Vol 1, No 3 (2018): September
Publisher : Institute for Research and Community Service (LP2M), Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (440.781 KB) | DOI: 10.17977/um045v1i3p%p

Abstract

Penggunaan sepeda motor trail saat ini mulai meningkat, namun untuk sepeda motor trail baru terkendala oleh harga yang cukup mahal sehingga banyak bermunculan bengkel modifikasi motor trail. Dalam melaksanakan proses modifikasi dibutuhkan mesin rol pipa untuk membentuk bengkokan pada frame bodi motor. Oleh karena itu, tujuan penulisan ini adalah memberikan pemaparan tentang desain dan manufaktur serta aplikasi mesin rol pipa pada UKM mitra dibidang modifikasi konstruksi frame motor trail. Metode pelaksanaan yang digunakan meliputi observasi dan wawancara tentang kendala proses rol, mendesain dan membuat mesin rol pipa serta menguji kualitas produk rol pipa dan membandingkan dengan mesin pipa lama yang dipakai. Hasil kegiatan telah menghasilkan mesin rol pipa dengan sistem penggerak hidrolis dengan daya maksimum mencapai 9 ton, dengan kapasitas diameter pipa yang di rol lebih besar yaitu kisaran 0,5-2 inchi. Keunggulan dari mesin yang dibuat adalah rentang aplikasi diameter pipa yang digunakan lebih besar, kebutuhan ruang kerja yang lebih kecil, kebutuhan tenaga lebih sedikit, penggunaan lebih nyaman dan aman, serta hasil yang diperoleh lebih presisi.  Kata kunci— mesin rol pipa, konstruksi motor trail, hidrolis
Struktur dan Sifat Mekanik Film Bacterial Cellulose dengan Disintegrasi Mekanis Muhamad Muhajir; Heru Suryanto; Aisyah Larasati
JPSE (Journal of Physical Science and Engineering) Vol 3, No 2 (2018): JPSE (Journal of Physical Science and Engineering)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Film structure was greatly affected to mechanical properties of Bacterial Cellulose (BC). An engineering effort on Bacterial Cellulose Fibers (BCF) structure was changing the size and distribution of BC fiber through mechanical disintegrator process using a High Speed Blender (HSB). This study aimed to show the effect of disintegrator to the structure and mechanical properties of BCF film. The method used in this study is a synthesis of BCF from fermentation from pineapple peel waste with incubation of Acetobacter xylinum (A. xylinum) for 14 days. BC pellicle was soaked by using 1% NaOH for 24 hours then distrusted using the HSB with code speed variation of L (18000 rpm), M (21000 rpm), and H (26000 rpm) for 5 min. Then film formed by a casting method and dried in the oven at a temperature of 60 °C for 8 hours. The study result showed that the morphology of BCF formed pores, the crystallinity decreased so the tensile strength was decreased by 94%. The results of this study are expected to provide engineering information on the BCF structure potentially for filters and for sensors. DOI: http://dx.doi.org/10.17977/um024v3i22018p055 
Effect of Homogenization Pressure on Bacterial Cellulose Membrane Characteristic Made from Pineapple Peel Waste Muhamad Muhajir; Heru Suryanto; Yanuar Rohmat Aji Pradana; Uun Yanuhar
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 6, No 1 (2022)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v6i12022p034

Abstract

Many studies were conducted to maintain the environment by reducing the waste, especially pineapple peel waste. This study aims to explore the effect of various pressure of the homogenization process on bacterial cellulose membrane surface morphology and structure produced using extract of pineapple peel waste. The methods include the preparation of pellicle samples from the product of the fermentation process of Acetobacter xylinum using a medium from the extract of pineapple peel waste. Bacterial cellulose pellicles were crushed using a blender. Mashed bacterial cellulose pellicle then homogenized in High-Pressure Homogenizer with pressure variation of  0 bar, 150 bar, 300 bar, 450 bar, dan 600 bar then cast into a mold. The bacterial cellulose solutions were dried in an oven at 60°C for 8 hours. The dried bacterial cellulose membrane was analyzed using XRD for the structure and SEM analysis for the morphology. The results indicate that the crystalline properties of BCM were shifted after being treated by various pressure processing in a High-Pressure Homogenizer. It was found that the High-Pressure Homogenizer with higher pressure reduced the peak intensity, decreased crystalline index from 87% to 70%, and decreased the degree of crystalline from 88% to 77%  without changing the cellulose structure. The higher pressure of the homogenization process causes the porosity of the membrane to be decreased.
Synthesis and Applications of Hematite α-Fe2O3 : a Review Muhajir, Muhamad; Puspitasari, Poppy; Abdul Razak, Jeefferie
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 3, No 2 (2019)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (739.115 KB) | DOI: 10.17977/um016v3i22019p051

Abstract

This article reviewed the hematite α-Fe2O3, which focuses on its material properties, nanostructures, synthesis techniques, and its numerous applications. Researchers prepared the hematite nanostructure using the synthesis methods, such as hydrothermal, and, further, enhanced it by improving the techniques to accommodate the best performance for specific applications and to explore new applications of hematite in humidity sensing.
UJI DAYA HASIL BEBERAPA VARIETAS JAGUNG TERHADAP PAKET PEMUPUKAN ORGANIK, ANORGANIK DAN PUPUK HAYATI MIKORIZA Muhajir, Muhamad; Astiko, Wahyu; Abdurachman, Hanafi
CROP AGRO, Scientific Journal of Agronomy Vol 16 No 2 (2023): Crop Agro, Juli 2023
Publisher : Department of Agronomy, Faculty of Agriculture, University of Mataram and Indonesian Society of Agronomy, NTB Branch

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/caj.v16i2.768

Abstract

The corn food commodity is one of the leading commodities of West Nusa Tenggara. In addition, NTB is also one of the target areas for increasing national maize production. This study aims to determine the yield yield of several varieties of maize given a mixed package of organic, inorganic and mycorrhizal fertilizers. This research was conducted from May to August 2020 in Midang Village, Gunung Sari District, West Lombok Regency, Microbiology Laboratory and Soil Physics and Chemistry Laboratory, Faculty of Agriculture, Mataram University. The method used in this study was a randomized block design with 5 treatments, namely V1 (P8IS variety), V2 (P8DPP variety), V3 (Gumarang variety), V4 (Lamuru variety), V5 (Sukmaraga variety). Each treatment was repeated 3 times in order to obtain 15 experimental plots. The results showed that maize varieties given organic, inorganic and mycorrhizal fertilizers had a significant effect on growth, yield of maize, nutrient status and nutrient uptake, number of mycorrhizal spores and root colonization by mycorrhizae. Sukmaraga variety has better growth and yield than other varieties, this is reflected in the growth parameter indicators and yield parameter indicators, namely harvest dry ear weight per plant (271.5 g), dry ear weight per plant (255 g), length ear (16.5 cm), ear diameter (5.3 cm), seed dry weight per plant (180 g), and weight 1000 seeds (288 g).
Karakterisasi, Sifat Mekanik, dan Aplikasi Komposit Biofoam Studi Literatur Muhajir, Muhamad; Reza Taufiqi Ivana; Taufik Abdullah Attamimi; Sri Muntiah Andriami; Uswatun Hasanah
RING ME Vol 5 No 2 (2025): RING Mechanical Engineering
Publisher : Universitas Islam Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33474/rme.v5i2.24070

Abstract

Starch based biofoams have emerged as a sustainable alternative to conventional plastics, yet their performance varies significantly depending on formulation and processing methods. This study aims to comprehensively evaluate the relationship between raw material composition, production techniques, and functional properties of biofoams through an integrated analysis of ten recent formulations. The methodology involved a systematic review of experimental data derived from diverse production methods, including thermopressing, microbial fermentation, evaporative drying, freeze drying, and molding. Results reveal that banana peel and cassava starch and banana stem fiber biofoam offers an optimal balance of high tensile strength 43.86 MPa, low water absorption 16.91%, and moderate biodegradability 65.82%, making it ideal for dry food packaging. In contrast, bamboo powder biofoam exhibits exceptional water absorption 97.1%, suitable for horticultural substrates, while bamboo cellulose–starch composite demonstrates outstanding compressive strength 78.74 MPa and thermal stability 410.86 °C, indicating potential for lightweight structural applications. These findings underscore that biofoam design must be application-specific, providing evidence-based guidance for developing effective, sustainable materials tailored to real world needs.
Teknologi dan Karakterisasi dalam Proses Produksi Arang Sekam Padi untuk Berbagai Aplikasi: Tinjauan Pustaka Muhamad Muhajir; Adhielia Noer Syaief; Pratama Yoga Wica
Jurnal Engine: Energi, Manufaktur, dan Material Vol. 9 No. 2 (2025)
Publisher : Universitas Proklamasi 45

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30588/jeemm.v9i2.2356

Abstract

Sekam padi merupakan limbah pertanian yang melimpah dengan potensi tinggi untuk diolah menjadi arang (biochar) melalui pirolisis sebagai bagian dari strategi pengelolaan biomassa berkelanjutan. Studi ini bertujuan untuk meninjau secara komprehensif teknologi dan karakterisasi yang terlibat dalam produksi arang sekam padi, serta mengevaluasi aplikasinya di berbagai sektor. Tinjauan ini dilakukan dengan pendekatan naratif, menganalisis literatur ilmiah terkini (2019–2024) yang relevan dengan sistem pirolisis berbasis tungku kisi miring dan metode karakterisasi biochar, seperti morfologi, kristalinitas, dan analisis gugus fungsi. Hasil penelitian menunjukkan bahwa sistem tungku kisi miring memberikan kontrol termal yang optimal, menghasilkan biochar berkualitas tinggi dengan struktur pori yang berkembang baik, stabilitas karbon yang baik, dan potensi tinggi untuk adsorpsi dan retensi hara. Biochar yang berasal dari sekam padi juga terbukti efektif sebagai amandemen tanah, penyerap polutan, penopang katalis, aditif semen, dan bahan bakar alternatif. Karakteristik ini sangat dipengaruhi oleh parameter proses dan desain reaktor. Temuan ini menggarisbawahi pentingnya pendekatan interdisipliner dalam mengoptimalkan teknologi biomassa. Studi ini berkontribusi pada pengembangan strategi produksi biochar yang lebih efisien dan menyediakan dasar untuk penelitian lebih lanjut tentang stabilitas jangka panjang dan dampak lingkungan dari penerapannya.
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.
Effect of Methyl Tertiary Butyl Ether (MTBE) Blending in Pertalite Fuel on Engine Performance and Exhaust Emissions of a 125 cc Vario Motorcycle Musthofa, Imron; Muhajir, Muhamad; Putra, Muhammad Rezki Fitri; Adhielia Noer Syaief, Adhielia Noer; Isworo, Hajar; Ivana, Reza Taufiqi
Journal of Earth Energy Science, Engineering, and Technology Vol. 9 No. 1 (2026): JEESET VOL. 9 NO. 1 2026
Publisher : Penerbitan Universitas Trisakti

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25105/6pp33n89

Abstract

The use of Methyl Tertiary Butyl Ether (MTBE) as an additive in Pertalite fuel has gained attention due to its potential to improve engine performance and reduce exhaust emissions in motorcycles. This study aims to evaluate the effects of MTBE on engine torque, power, and exhaust emissions in a Honda Vario 125cc using three fuel mixtures: standard Pertalite, Pertalite with 10% MTBE, and Pertalite with 20% MTBE. The experimental methodology involved measuring engine performance using a dynotest and analyzing emissions using an exhaust gas analyzer. Fuel consumption was also recorded to assess efficiency. The results revealed that the 10% MTBE mixture (A10) significantly increased engine torque and power compared to the standard Pertalite, while reducing CO emissions. However, the 20% MTBE mixture (A20) led to reduced performance and increased emissions, particularly hydrocarbons, indicating that excessive MTBE negatively impacts combustion efficiency. The optimal concentration of MTBE was found to be 10%, which balanced performance improvement with emission reduction. These findings highlight the potential of MTBE to optimize fuel performance and reduce environmental impact. Future research should explore other fuel additives and further refine MTBE concentrations for more sustainable fuel formulations.
Co-Authors Abdul Razak, Jeefferie Abdurachman, Hanafi Adhielia Noer Syaief Adhielia Noer Syaief, Adhielia Noer Aisyah Larasati Aminnudin, Aminnudin Bayu Agung Wicaksono Fakris Muslim Heru Suryanto Imron Musthofa Isworo, Hajar Ivana, Reza Taufiqi Muhammad Rezki Fitri Putra Musthofa, Imron Pradana, Yanuar Rohmat Aji Pratama Yoga Wica Putra, Muhammad Rezki Fitri Reddy .A. Dharmabintara Reza Taufiqi Ivana Rr. Poppy Puspitasari Sri Muntiah Andriami Taufik Abdullah Attamimi Uswatun Hasanah Wahyu Astiko Yanuar. R. A. Pradana Yanuhar, Uun