The application of hydrogen enrichment of palm oil-based biodiesel in a compression ignition engine was examined in this work. Synthesized from crude palm oil (CPO), biodiesel was first fed into a single-cylinder diesel engine. The intake manifold received hydrogen gas at flows of 2.5 L/min, 5 L/min, 7.5 L/min, and 10 L/min. Operating at a constant speed of 2,000 rpm, the single-cylinder, direct-injection diesel engine used The aim of this work is to assess the performance and emissions of a diesel engine utilizing hydrogen gas and CPO biodiesel fuels. This work examined engine performance and exhaust emissions using smoke emissions, exhaust temperature, power, thermal efficiency, and fuel economy. Addition of hydrogen improved emissions and performance. Optimal engine performance was achieved by adding 2.5 L/min of hydrogen, which resulted in a 20.12% increase in brake thermal efficiency (BTE) and a 27.57% reduction in fuel consumption compared to biodiesel. The addition of hydrogen gas has a positive impact on exhaust emissions (HC, CO2, and smoke opacity), but has a negative impact on NO emissions. At elevated loads of 2.5 lpm hydrogen flow, emissions measured were 40.00 ppm, 0.04%, 4.20%, and 44.20%, respectively, alongside a 45.72% increase in NO emissions. Including hydrogen gas improves the diesel engines running on biodiesel's performance and exhaust pollutants.

Aluminum alloy is crucial for lightweight and fuel-efficient vehicles due to its strength, lightness, and corrosion resistance. However, welding aluminum vehicle parts poses challenges, particularly porosity issues caused by trapped hydrogen gas in the weld metal. This study aimed to investigate the impact of the welding room environment on the health and properties of aluminum welding joints. To achieve this, an isolated room was created, where variations in airflow velocity (1.1 m/s, 1.6 m/s, and 2.1 m/s) and temperature (19 °C, 27 °C, and 35 °C) were implemented. The fume condition of the room was assessed to determine its impact on health aspects, while bead appearance and macrostructure were evaluated to assess weld joint quality. Results revealed that higher airflow velocity and temperature reduced fume concentration in the welding room, indicating a healthier environment. However, these conditions also led to increased porosity defects and influenced the performance of the shielding gas. Additionally, higher ambient temperatures increased hydrogen solubility in the molten aluminum, exacerbating porosity issues. For optimal welder comfort and high-quality weld joints, it is recommended to maintain a low temperature and airflow velocity in the welding room, ensuring a healthier working environment while minimizing porosity defects.

Engine coolant plays an important role in maintaining optimal engine performance, where it has good effectiveness and can prevent corrosion in the engine cooling system (radiator). This study aims to determine the effect of the use of coolant variations (engine coolant) on the effectiveness of engine cooling (radiator) and to determine the effects of the coolants on the corrosion rate. To achieve this, coolant variations were used in the forms of mineral water, radiator coolant (prestone), and power coolant (TOP 1), which were applied at engine speeds of 1000, 1500, and 2000 rpm. Temperature data collection at the coolant inlet and outlet was carried out every 10 min at different rpm. The corrosion rate test used the AA 3102 series aluminum radiator material, which was tested using the potentiodynamic polarization method. The results showed that the best coolant effectiveness value was found for the power coolant (TOP1). This is influenced by the ethylene glycol contained within it, which helps to accelerate the decrease in temperature in the engine. The lowest corrosion rate was found for the power coolant (TOP1), with a corrosion rate value of 0.0074480 mm/year. This is because the power coolant (TOP1) contains organic carboxylate rust inhibitors, which can inhibit corrosion.

AA 1100 aluminum is widely used in industrial applications due to its low density and good corrosion resistance; however, welding defects such as porosity and changes in mechanical properties often occur during Gas Metal Arc Welding (GMAW). One of the most influential parameters on weld quality is the welding current. This study analyzes the effect of welding current variations on the physical and mechanical properties of AA 1100 GMAW welded joints using ER 5356 filler wire. Welding was carried out at currents of 100 A, 130 A, and 160 A using argon shielding gas. The welded joints were evaluated by visual inspection, macrostructure observation, microstructure analysis, and Vickers microhardness testing. The test results showed that increasing the welding current resulted in wider weld beads, increased porosity and spatter defects, as well as coarser grain structures in the heat-affected zone (HAZ) and weld metal. The lowest porosity and spatter occurred at 100 A, while the highest porosity and spatter occurred at 160 A. This was due to excessive heat input and hydrogen trapping. Microstructural analysis revealed the presence of FeAl₃ intermetallic phases dispersed within the aluminum matrix. The highest hardness value was found in the weld metal region at 100 A, which was caused by the finer grain size and the strengthening effect of Mg from the ER 5356 filler. Overall, this study confirmed that the welding current significantly affects the defect formation, microstructural evolution, and hardness distribution of GMAW AA 1100 weld joints.

Leaf spring steel mempunyai peran yang sangat penting pada mobil masa kini yaitu sebagai penopang beban dan peredam getaran. Penelitian ini dilakukan untuk mengetahui pengaruh quenching dan tempering terhadap sifat fisik dan mekanik pada leaf spring steel JIS SUP 9A. Metode penelitian menggunakan sampel leaf steel spring bekas pakai dengan tipe JIS SUP 9A kemudian diberi perlakuan panas hardening dengan suhu 850℃ di tungku furnace ditahan dengan waktu 60 menit kemudian diquenching dengan air, cairan dromus, dan campuran air dengan cairan dromus, setelah di quenching kemudian dilakukan proses tempering dengan suhu 300℃ ditahan dengan waktu 30 menit kemudian didinginkan di suhu udara. Hasil penelitian menunjukkan bahwa sampel tanpa perlakuan menghasilkan fasa ferrite yang dominan sedangkan sampel pendingin air menghasilkan fasa pearlite yang banyak dibandingkan variasi pendingin dromus dan pendingin campuran air dengan dromus. Ketika fasa ferrite lebih dominan daripada fasa pearlite maka nilai kekerasan yang dihasilkan akan rendah, sebaliknya jika fasa pearlite lebih dominan daripada fasa ferrite maka nilai kekerasan yang dihasilkan akan semakin tinggi. Sifat mekanik terbaik yaitu dicapai dengan variasi media pendingin menggunakan air dengan kekerasan microvickers sebesar 63,85 HVN sedangkan nilai kekerasan terendah menggunakan campuran air dengan dromus yaitu sebesar 56,89 HVN. Hal ini disebabkan karena campuran air dengan dromus memiliki volume yang kental sehingga menghasilkan laju pendinginan yang lambat dan mengakibatkan nilai kekerasan yang sangat rendah.

Latar Belakang: Stunting adalah masalah serius yang perlu penanganan khusus karena dapat mempengaruhi pertumbuhan anak balita akibat kurang gizi. Kuliah Kerja Nyata di Desa Krisik selain pengabdian kepada masyarakat juga membawa misi untuk mengatasi stunting yang masih jadi tantangan. Metode: Pengabdian masyarakat oleh tim Tematik Fakultas Teknik Universitas Muhammadiyah Ponorogo menciptakan website untuk mendeteksi stunting menggunakan algoritma K-Nearest Neighbor. Algoritma ini mengklasifikasikan status gizi berdasarkan data antropometri. Prosesnya termasuk pengumpulan data, analisis menggunakan KDD dan pengembangan website. Hasil: Hasil kegiatan ini adalah sebuah website informasi deteksi stunting di desa krisik yang dapat menampilkan data stunting, artikel yang berupa foto dan informasi, layanan konsultasi dan cek gizi yang ditampilkan untuk masyarakat luas. Kesimpulan: Algoritma KNN mencapai akurasi 99,90% dalam memprediksi status gizi balita. Website ini membantu tenaga medis dan masyarakat mendeteksi risiko stunting secara dini dan memberikan informasi edukatif. Semoga sistem ini meningkatkan kesadaran masyarakat dan mengurangi stunting di Desa Krisik