The application of flat plates to the field of wind harvesting requires a lot of research toward the understanding of the flutter behavior of the plates. There are shortages of articles that discuss the effect of varying the angles of attack to the flutter speed of a flat plate. This research aims to conduct a basic experimental research on the effect of relative position of a thin-flat plates to the direction of the air flow to its flutter speed. In this study, a thin-flat plate was placed in a subsonic wind tunnel to test its flutter speed. The position of the plate was varied in various angles of attack. The effect of the angles of attack to the flutter speed was observed.

This paper shows the experimental results of the flutter speed of thin-flat plates with free leading edge in axial flow as a function of plates' geometry, fluid densities, and viscosities, as well as natural frequencies of the plates. The experiment was developed based on similitude theory using dimensional analysis and Buckingham Pi Theorem. Dimensional analysis generates four dimensionless numbers. Experiment was conducted by placing the thin-flat plates in a laminar flow wind tunnel in order to obtain the relationship among those dimensionless numbers. The flutter speed was measured by varying the flow velocity until the instability occurred. The dimensional analysis gives a map of the flutter Reynolds number as a function of a new type of dimensionless number that is hereby called flutter fluid structure interaction number, thickness-to-length, and aspect ratios as the correcting factors. This map is a very useful tool for predicting the flutter speed of thin-flat plates in general. This investigation found that the flutter Reynolds number is very high at the region of high flutter fluid structure and thickness-to-length ratios numbers; however, it is very sensitive to the change of those two dimensionless numbers. The sensitivity is higher at lower aspect ratio.

Cocoa plantations have employed thousands of farmer families throughout Indonesia, as well as have been the third largest export among the plantation sub-sector after rubber and oil palm. Therefore, the potential for the development of the cocoa industry as one of the drivers of growth and income distribution is very open. Cocoa bean production in Indonesia continues to increase, but the quality produced is still diverse such as less fermented, not dry enough, uniform bean size, high skin content, high acidity, and very diverse flavors. In this research, efforts to overcome these problems are accomplished by designing a cocoa bean sorting machine that can separate clean cocoa beans and root debris from cocoa beans so as it is expected to make it easier for cocoa farmers, workers, entrepreneurs and industries to more easily get a cocoa bean sorting machine so that the quality of cocoa beans improves and their selling price increases. Seeing these challenges, the authors took the initiative to create a new design a cocoa bean sorting machine with a simpler and more precise design.

Pada penelitian ini diamati peran pengelompokan molekul terhadap kinerja mesin yang dihasilkan bahan bakar hydrous etanol (95,5%v). Pengujian dilakukan menggunakan pembebanan bervariasi pada motor bakar satu silinder empat langkah. Kinerja mesin diukur menggunakan Engine Brake Power indikator load cell tipe TD 800PM. Kinerja mesin yang dihasilkan oleh anhydrous etanol juga diuji. Kinerja mesin yang dihasilkan kedua bahan bakar tersebut dibandingkan. Hasil penelitian menunjukkan Daya mesin yang dihasilkan hydrous etanol sedikit lebih tinggi dari anhydrous etanol. effisiensi pengisian yang dihasilkan oleh hydrous etanol lebih tinggi dari anhydrous etanol.

Menurunnya cadangan minyak dunia menjadi krisis global untuk beberapa dasawarsa ke depan. Pencarian alternatif energi terbaharui menjadi topik urgen tren penelitian saat ini. Indonesia memiliki keberlimpahan ketersediaan energi berupa potensi pengembangan mikrohidro. Penelitian ini merupakan penelitian pengembangan teknologi inovatif baru dalam teknologi mikrohidro berupa teknik pengkonversian energi aliran air menjadi energi listrik menggunakan teknologi hidro flutter. Dalam penelitian ini dilakukan pengembangan alat baru pengkonversian energi dari aliran air menjadi energi listrik. Sebuah purwarupa dibangun yang bisa pengekstrak energi dari aliran air di kali menjadi energi mekanik yang siap di konversi menjadi energi listrik menggunakan prinsip hydro flutter dari sebuah flexibly mounted free leading edge cantilevered rigid plate. Keunggulan dari konsep baru yang ditawarkan adalah kesederhanaan dari desain dan kemampuan untuk membersihkan sistem sendiri sehingga mengurangi biaya pemeliharaan.