Mohamad Zaenudin

Performance of piezoelectric energy harvesters at various angles

The global energy crisis caused by the limits of oil reserves urging the needs for alternative energy solution, including a pyrolysis-based oil energy. In this study, we investigate the pyrolysis of corn cob biomass with varying particle sizes (3 mesh, 5 mesh, 7 mesh, and 10 mesh) to evaluate its effect on product yields and physical properties. Each experiment was conducted for 90 minutes using 300 grams of feedstock, pre-dried in a microwave oven at 120°C for 2 hours. The results revealed that the bio-oil yield decreased with smaller particle sizes, from 31.52% at 3 mesh to 26.12% at 10 mesh. Conversely, bio-char yield increased from 37.48% to 46.47%, while bio-gas yield decreased from 31.00% to 27.42%. This suggests that excessively small particle sizes reduce bio-oil yield due to uncontrolled reactions despite their higher surface area. The bio-oil density ranged between 1.0235 and 1.0353 g/ml, indicating consistent physical properties across particle sizes. The inlet and outlet temperatures of the reactor (T1 and T2) and condenser (T3 and T4) remained relatively increasingly stable, indicating consistent condensation of pyrolysis gases into liquid bio-oil. This study has successfully provided an insight into the optimization of particle size of the waste processing of corn cob into energy by using the pyrolysis method.

The global energy crisis caused by the limits of oil reserves urges the need for alternative energy solutions, including pyrolysis-based oil energy. In this study, we investigate the pyrolysis of corn cob biomass with varying particle sizes (3 mesh, 5 mesh, 7 mesh, and 10 mesh) to evaluate its effect on product yields and physical properties. Each experiment was conducted for 90 minutes using 300 grams of feedstock, which had been pre-dried in a microwave oven at 120°C for 2 hours. The results revealed that the bio-oil yield decreased with smaller particle sizes, from 31.52% at 3 mesh to 26.12% at 10 mesh. Conversely, bio-char yield increased from 37.48% to 46.47%, while bio-gas yield decreased from 31.00% to 27.42%. This suggests that excessively small particle sizes reduce bio-oil yield due to uncontrolled reactions despite their higher surface area. The bio-oil density ranged between 1.0235 and 1.0353 g/ml, indicating consistent physical properties across particle sizes. The inlet and outlet temperatures of the reactor (T1 and T2) and condenser (T3 and T4) remained relatively stable, indicating consistent condensation of pyrolysis gases into liquid bio-oil. This study has successfully provided insight into the optimization of a particle size of the waste processing of corn cob into energy by using the pyrolysis method

Kebutuhan akan komposit ramah lingkungan mendorong pemanfaatan bio-fiber sebagai penguat. Penelitian ini mengkaji pengaruh variasi massa serat resam (Dicranopteris linearis) dan ijuk (Arenga pinnata) serta perlakuan alkalisasi NaOH 5% (2 jam) terhadap kekuatan tarik komposit bermatriks epoksi. Spesimen dibuat dengan metode hand lay-up sesuai ASTM D638 Tipe I pada tiga tingkat massa serat (1, 2, 3 g) untuk dua kondisi (tanpa alkalisasi dan beralkalisasi), masing-masing dua replikasi (total 24 spesimen). Hasil pengujian menunjukkan respons yang berbeda antara kedua serat. Pada ijuk, perlakuan alkalisasi menghasilkan tren kenaikan kekuatan tarik yang linier dan stabil seiring meningkatnya massa (27,42 → 31,88 → 34,59 MPa; R² ≈ 0,98), sekaligus menurunkan variasi data (coefficient of variant (CV) kelompok ≈11,6%). Tanpa alkalisasi, kekuatan material cenderung lebih lemah (29,07 → 19,08 → 36,06 MPa; R² ≈ 0,17) dengan variasi yang lebih tinggi (CV ≈30,4%). Pada resam, alkalisasi menghasilkan nilai optimum pada fraksi massa 2 g (22,43 MPa) namun menurun di 3 g (16,10 MPa), sedangkan tanpa alkalisasi nilainya moderat (16,53; 19,38; 16,12 MPa) dengan konsistensi lebih baik (CV ≈ 10,27% vs 18,61% beralkali). Seluruh kekuatan tarik melebihi acuan SAE J1717 (8,09 MPa).

Tingginya angka kecelakaan lalu lintas yang melibatkan truk (12%) menggarisbawahi urgensi peningkatan keselamatan kendaraan berat ini. Penelitian ini dilatarbelakangi oleh seringnya insiden akibat patah as atau poros belakang. Untuk memahami fenomena ini, simulasi Finite Element Analysis (FEA) diterapkan guna memvisualisasikan sebaran tegangan dan deformasi pada poros belakang dump truck HINO 500. Analisis ini dilakukan dengan memvariasikan beban 26-35 ton, mencakup beban standar dan overload) dengan tujuan utama mengidentifikasi area konsentrasi tegangan dan potensi titik kegagalan fatik pada poros roda. Hasil penelitian menunjukan bahwa tegangan tertinggi terjadi variasi beban 35 Ton dengan nilai tegangan sebesar 1,76 x 10^8 N/m^2 dengan nilai tegangan tertinggi terjadi pada bagian ujung poros roda gigi dan ujung bagian dekat piringan. Nilai masih terbilang aman karena nilai tegangan lebih kecil dari nilai batas tegangan material yaitu 4,6 x 10^8 N/m^2. Sementara hasil simulasi FEA defleksi sebesar 4,026 x 10^-3 m dan hasil simulasi fatigue failure menunjukan pada variasi beban 26 ton memiliki life cycle terbesar 314.886 dan nilai life cycle terkecil terjadi pada variasi beban 35 Ton dengan nilai life cycle sebesar 46.523.

Penelitian ini bertujuan untuk meneliti mengenai pengaruh variasi jumlah mata pisau, kecepatan putaran mesin, dan ukuran saringan terhadap kinerja mesin penggiling jagung. Mesin penggiling jagung yang digunakan dilengkapi dengan motor gerinda dan dilengkapi dengan tiga variasi jumlah mata pisau (2, 3, dan 4 bilah), dua kecepatan putaran mesin (50% dan 100%), serta dua ukuran saringan (3 mm dan 6 mm). Pengujian dilakukan untuk mengukur kapasitas produksi dan kecepatan penggilingan berdasarkan kombinasi tersebut. Hasil penelitian menunjukkan bahwa kombinasi jumlah mata pisau dan kecepatan putaran berpengaruh signifikan terhadap waktu penggilingan. Penggunaan 2 bilah mata pisau dengan kecepatan putaran 100% pada saringan 6 mm menghasilkan waktu penggilingan tercepat, yaitu 14,93 detik. Sementara itu, peningkatan jumlah mata pisau justru mengurangi efisiensi produksi, terutama pada kecepatan putaran yang lebih tinggi. Selain itu, saringan berukuran 6 mm cenderung menghasilkan kapasitas produksi yang lebih besar dibandingkan dengan saringan 3 mm. Dari penelitian ini dapat disimpulkan bahwa untuk mencapai efisiensi maksimal dalam penggilingan jagung, kombinasi yang paling optimal adalah penggunaan 2 bilah mata pisau, kecepatan putaran 100%, dan saringan 6 mm. Hasil ini menunjukkan bahwa mesin penggiling jagung yang diuji mampu memberikan hasil yang stabil dan dapat diandalkan dengan variasi parameter yang berbeda.

Piezoelectric energy harvesters (PEHs) are gaining attention for their ability to generate electrical energy from environmental vibrations, with applications in various industries. This study focuses on optimizing the performance of a PEH using a cantilever system driven by wind energy through the impact of windmill blades. The objective is to evaluate how the number of windmill blades affects the PEH's voltage output and vibration stability. Experiments were conducted in a wind tunnel with a 250 mm × 250 mm cross-section equipped with a 12-inch blower to generate airflow. Three windmill configurations—3 blades, 4 blades, and 5 blades—were analyzed for output voltage and deflection of two PVDF-based PEHs placed at a 30° angle. Results indicate that the 3-blade configuration produced the highest voltage (1.79V), 4% and 43% higher than the 4-blade (1.71V) and 5-blade (1.01V) configurations, respectively. This configuration also exhibited maximum deflection and lower frequency vibrations. Increasing blade count led to higher frequency vibrations but reduced deflection and voltage output. The study highlights that fewer blades result in greater deflection and better energy harvesting performance. These findings contribute to ongoing research in PEH systems, offering insights into optimizing energy harvesting from fluctuating wind conditions by balancing deflection amplitude and vibration frequency.

The use of solar panels in electric power charging stations is becoming increasingly popular as part of efforts to adopt renewable energy sources. In this context, the structural framework supporting the solar panels plays a crucial role in maintaining the stability and reliability of the system. Therefore, this thesis aims to investigate the influence of various structural framework variations on the strength of static loading in solar-powered electric charging stations. The research methodology employed simulation of static loading at three different load levels, namely 40 kg, 50 kg, and 60 kg. The analysis was conducted by comparing the equivalent stresses and total deformations between "Design 1" and "Design 2" at each load level. The research findings reveal significant differences in equivalent stresses and total deformations between the two designs at each load level. Design 1, with a stiffer structural framework, exhibited higher equivalent stresses and greater total deformations compared to Design 2. Consequently, this study provides a deeper understanding of the influence of various structural framework variations on the strength of static loading in solar panel support structures. These findings can serve as a basis for optimizing the structural design of solar-powered electric charging systems.