Direct Methanol Fuel Cell (DMFC) can operate at low temperatures, but efficiency and performance are greatly influenced by the material. On the other hand, sulfonated ketone polyether ethers (sPEEK) which have high thermal resistance, ductile, chemical resistance and high mechanical properties, can be combined with chitosan which has good proton conductivity properties. The sPEEK-Chitosan membrane is known to have good mechanical and thermal resistance, but its conductivity is low. The addition of graphene oxide as a filler material can increase the proton conductivity due to its properties. This research was conducted with a completely randomized design of 1 factor to investigate the characteristics of the sPEEK-Chitosan composite membrane as the dependent variable and the addition of graphene oxide solution to the variables 0, 1, 3, 6, and 9% w/w as independent variables. The test results show that the water uptake is in the range of 8.82-33.34%, the swelling degree is in the range of 5.55-20.75%, and the ion exchange capacity is 0.1875-0.2714 meq/g. With this good character, the sPEEK-chitosan membrane with the addition of graphene oxide is a promising candidate for DMFC applications.

High Speed Steel (HSS) tool is commonly used in engineering applications, especially as cutters. The shortfall of this materials are wear and corrosion. However, these can be reduced by coating the surface of the material. Therefore, the purpose of this research is to investigate the effects of Diamond Like Carbon (DLC) coating, quenching heating treatment, and tempering on the physical and mechanical properties of HSS surface. The physical characteristics which will be investigated is the micro structure, while the mechanical characteristics are hardness, wear and corrosion rate. HSS has variations in their chemical composition (% mass): 0.75–1.5 C, Co >12, V > 5, 4–4.5 Cr,10–20 W and Mo. Furthermore, DLC coating uses Plasma Assisted Chemical Vapor Deposition (PACVD) technique with variation in the duration of coating (1,2,3,4,5 and 6 hours) at temperature of 300℃, with pressure variations of 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 millibar. DLC coating material be treated from methane or ethane gas, which is streamed into the fire with Argon (Ar). The result shows variations in DLC coating and the hardness grade depends on the coating time and pressure variation. DLC coating for a duration of 4 hours under 1.8 mbar pressure can reduce the surface hardness of HSS tool by 62% accompanied by increased ductility.

One of the reasons for the slow conversion program from gasoline to LPG/Vigas is the uncertainty of profit or loss. Therefore, this article presents a simple calculator to assess the feasibility of investing in vehicle conversion, from gasoline to LPG/Vigas. Input parameters include estimated annual mileage, fuel consumption, gasoline prices, LPG / Vigas prices, the cost of the converter kit and its installation, engine standardization costs, maintenance costs with gasoline, and maintenance costs with LPG considered to produce output parameters that include Break Even Point (BEP), Payback period (PP), Net Present Value (NPV), and Internal Rate of Return (IRR).

Artikel ini menyajikan hasil penelitian tentang pengaruh tipe busi terhadap emisi gas buang sepeda motor. Pengujian dilakukan di Bengkel Prototype Honda Jurdiknik Otomotif FT UNY dengan obyek uji adalah sepeda motor 4 tak 135 cc pada putaran mesin 1500, 3000, dan 5000 rpm. Masing-masing pengujian dilakukan pengulangan sebanyak 3 kali untuk mendapatkan hasil yang lebih akurat. Hasil penelitian menunjukkan bahwa jika dibandingkan dengan pemakaian busi standar, busi platinum menurunkan kadar emisi CO 20% dan HC 41%, busi iridium menurunkan kadar CO 29% dan HC 61%, dan pemakaian busi multi elektrode menurunkan kadar CO 8% dan HC 29%.

Magelang memiliki tingkat kemacetan yang cukup padat pada beberapa ruas jalan terutama yang menuju pusat kota, salah satunya pada simpang Armada Town Square Mall yang kian hari semakin padat. Oleh karena itu, artikel ini menyajikan analisis pemborosan bahan bakar akibat kemacetan dengan menggunakan citra google map. Dalam penelitian ini metode yang digunakan dengan melihat panjang kemacetan pada google map, kemudian menghitung jumlah dan jenis kendaraan yang terjebak dalam kemacetan. Hasil penelitian menunjukkan bahwa kerugian ekonomi akibat kemacetan lalu lintas di simpang Armada Town Square Mall Magelang dari arah Yogyakarta sebesar 147,13 liter per hari untuk gasoline dan 777,82 liter untuk solar. Estimasi kerugian ekonomi akibat kemacetan lalu lintas dalam rupiah sangat bervariatif menurut jenis bahan bakar yang digunakan. Kerugian minimal dalam satu hari adalah Rp. 4.950.000,- ketika menggunakan premium dan solar subsidi, sedangkan kerugian maksimum adalah Rp. 9.940.000,- ketika menggunakan pertamax turbo dan pertamina dex.

Artikel ini menyajikan hasil studi eksperimen karakteristik konsumsi bahan bakar sepeda motor 110 matic dengan CDI BRT dan CDI standar Pengambilan data dilakukan pada putaran 1000, 2000, 3000, dan 4000 rpm dengan model full factorial design. Konsumsi bahan bakar untuk setiap pengujian diukur dalam ml/m. Hasil penelitian ini menunjukkan bahwa konsumsi bahan bakar dengan CDI BRT dibawah CDI standar untuk semua rentang putaran mesin yang diuji. Sebagai kesimpulan, tipikal CDI BRT menjanjikan untuk diterapkan sebagai upaya untuk menghemat bahan bakar.