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ABSTRAK--Penelitian

Pelek adalah bagian unit kendaraan yang berfungsi sebagai penahan/penopang beban kendaraan pada saat keadaan diam, serta sebagai penerus gerak putar dari mesin untuk memindahkan kendaraan dari satu tempat kepada tempat yang lain. Pelek kendaraan ini adalah untuk kendaraan roda 4 dengan bahan baku utama adalah aluminium serta dipadukan dengan bahan lain (alloy) dengan paduan aluminium alloy 1060.Pada pelek ini melalui beberapa tahapan proses pengujian untuk mengetahui kekuatan pada saat static dan dinamik. Adapun proses analisa yang dilakukan dengan metode perhitungan yang disesuaikan dengan literature dari SNI 1869 -2008 tentang standar pelek kendaraan bermotor, serta mempergunakan simulasi system software komputansi SOLID WORK 2017. Pada proses SOLID WORK dilakukan dengan simulasi static, torsi, dan FEA (Finite Element Analysis). Pelek yang dilakukan pada analisis terdiri dari tipe 1, 2, dan 3. Hasil yang diperoleh dari analisa perhitungan dan pengujian secara matematis adalah hampir mendekati dari system analisis komputansi. Dari beberapa pelek yang telah dilakukan pengujian secara soft ware SOLID WORK 2017, penulis memperoleh hasil pelek 2, yang lebih unggul dari tipe 1 dan 3. Keunggulan pelek tipe berupa nilai displacement sebesar 8.576e-3 mm (pada simulasi static), Von Mises Stress sebesar 9.629e+7 N/m2, displacement sebesar 2.189e-1 mm, strain sebesar 8.832e-4 (pada simulasi torsi), dan displacement sebesar 2.311e-2 mm (pada simulasi FEA).

R-80 is a regional passenger aircraft with twin-turboprop engine designed by PT Regio Aviasi Industry. In this era, R-80 existence in Indonesian aviation market is still not perceived, while the purpose of creating R-80 is to supply local demand. Meanwhile, most of airlines in Indonesia prefer using ATR-72 as their fleet. If we look at Indonesia's airports condition, plenty airports runaways length are less than 1400 meters. R-80, need only 1,200 meters for take off and landing, is really suitable to use in Indonesia. R-80 also has a bigger fuselage than ATR-72; make it more efficient in carrying passengers. R-80 fuel capacity is less than ATR but it can carry more payload than ATR, it makes R-80 has less fuel consumption. This journal use SWOT analysis as a method to identify the internal and external factors that will affect the company's project.

<abstract> <p>Low-temperature latent heat storage (LHS) systems are suitable for incorporating paraffin as the storage material. However, they face difficulty in actual implementation due to low thermal conductivity (TC). The present study used volcanic ash as an environmentally friendly and cost-effective material to increase the TC of paraffin. Three composites of paraffin/ash were prepared with ash proportions of 10 wt%, 30 wt% and 50 wt%. Characterizations were done to evaluate the average TC and properties. Thermal performance evaluation was conducted by analyzing the static charge/discharge cycle. The average TC for paraffin was 0.214 W/m·K. Adding volcanic ash improved the TC to 19.598 W/m·K. It made the charge/discharge performance of the composite better than that of pure paraffin. The charge rate for the composite ranged from 3.83 ℃/min to 5.12 ℃/min. The highest discharge rate was obtained at 4.21 ℃/min for the composite paraffin₅₀/ash₅₀. The freezing temperature for the composite is influenced by the ash proportion, which can be taken as a suitable approach to adjust the freezing point of paraffin-based thermal energy storage (TES). The detailed results for the characterization and thermal performance evaluation are described thoroughly within the article. The overall result indicates that volcanic ash is applicable for improving the TC and charge/discharge rate of paraffin-based TES.</p> </abstract>

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The reflector durability is essential to maintain suitable photo-to-thermal conversion in concentrated solar power plants. The present study evaluates the impact of environmental exposure and accelerated aging of the reflector material. The study is conducted to assess the reflector material's durability to withstand environmental exposure and accelerated aging test. The evaluation is conducted using four different reflector materials commonly used in concentrated solar power: stainless steel and silvered-glass mirror (solid-state reflector), aluminum and silvered-polymer film (sheet-based reflector). The environmental exposure and accelerated aging test are conducted for 1,080 hours according to the standard reference of ISO 8565:2011 and ASTM B117–11. The mass loss after exposure is used as a reference to determine the corrosion rate for each reflector. Further observation is conducted by using microscope light to observe the effect of exposure on the surface of the reflector. Each reflector indicates a different corrosion rate which implies different weather resistance for each reflector type. The highest corrosion rate is found on aluminum film, with a value of 295.8 g/m2.year. The accelerated aging test through neutral salt spray demonstrates that a metallic reflector has a higher corrosion rate compared to a silvered-glass mirror which uses silicon dioxide as the top coating. Microscope observation demonstrates that suitable protection from soiling elements for the silvered-glass mirror is mainly caused by the presence of silicon dioxide on the top surface of this reflector. The assessment suggests that a suitable coating can be developed to be used for reflector protection. Furthermore, the corrosion mechanism is observed clearly, which can be referred to the synthesis of new reflective material that withstands environment and salt exposure.