Husk is a waste from the grinding process with the characteristics of a hard, scaly and dry layer. In the rice milling process, according to the Agricultural Research and Development Agency, the Department of Agriculture obtained 20-30% of rice husk, 8-12% of bran and 50 - 63.5% of milled rice. It can be seen that the amount of waste produced is predominantly dominated by rice husk and if not handled it will be a problem for the environment. One effort to reduce the form of waste was carried out research design of rice husk grinding machine become powder. The implementation method starts with designing, manufacturing and testing. The design of the grinding machine is planned to use a fuel motor drive, the transmission uses a V belt and the type of grinder is a combination of discmill and hammermill.The results of research and design obtained rice husk grinding machine with specifications dimensions of 1100 mm high, 400 mm long and 500 mm wide, Hyundai gasoline engine drive HDE 390 with power 7.6 kW, elbow profile frame 50 mm x 50 mm, belt transmission and pulley with a ratio of 1: 1, a combination milling mechanism namely hammer mills which have 3 single hammer attrition mills and a front through grinder with the help of screw conveyor components. The test results of the grinding machine capacity obtained a production capacity of 10 kg / hour, and fuel consumption which is 2.162 liters / hour.

Tension Leg Platform (TLP) is an offshore platform structure used for deep-sea oil and gas exploration. The main structure of the TLP consists of a deck, pontoon, mooring system, and foundation. TLP operates in a balance of buoyancy, structural weight, and mooring tension. The problem is the construction of TLP in the deep sea, where sometimes extreme waves appear could damage the TLP structure. This paper proposes a new model of TLP that is more stable to extreme waves. The method is to separate the mass of the deck and the mass of the pontoon into two flexible parts, which are connected by a cantilever spring system. Thus the TLP motion becomes two degrees of freedom (TLP 2-DOF). Using the dynamic vibration absorber (DVA) method, the ratio of the deck mass, pontoon mass, and spring stiffness are adjusted so that the primary mass movement is minimal. Furthermore, the ratio of the amplitude of the deck movement as the primary mass to the wave amplitude is analyzed, which is known as the operator response amplitude (RAO). The results showed that the TLP 2-DOF model was more stable. As an illustration, at resonance conditions, this model can reduce RAO to about 67%.

Geopolymer is a material synthesized from a base material with a large amount of silica and alumina. Geopolymer can be used as an affordable alternative as a substitute for Portland cement, reducing pollution, and resistant to fire under certain conditions. But pure geopolymer has not been widely used in industrial areas because overall it has low toughness and mechanical properties when compared to metals or ceramics. This research was conducted to produce geopolymer composite material with good mechanical properties and can be applied as a material in making environmentally friendly pipes, by identifying the influence of the composition of the geopolymer base material using the Taguchi method. Generate Geopolymer composites with the addition of Silica Powder and random short carbon fiber have good mechanical properties, from the results of the experiment produced the best flexural strength in T9 specimens with details of the composition of Silica Powder (27 g), Kaolin (55 g), CaO (6 g), and Carbon Fiber (13 gr) with a flexural strength of 41.46924655 MPa and flexural modulus 6 GPa.

The behavior of piping elbows under bending and internal pressure is more complicated than expected. The main problem is that the coupling of bending and internal pressure is nonlinear; the resulting stress and displacement cannot be added according to the principle of superposition. In addition, internal pressure tends to act against the effect caused by the bending moment. If bending moment ovalise the elbow cross-section, with internal pressure acting against this deformation, then the ovalised cross section deform back to the original circular shape. It is then introduced the term “pressure reduction effect”, or in some literature, “pressure stiffening effect”. Current design piping code treats the pressure reduction effect equally for in-plane (closing and opening) moment and outof- plane moment. The aim of this paper is to present results of a detailed finite element analysis on the non-linear behavior of piping elbows of various geometric configurations subject to out-of-plane bending and internal pressure. Specifically the standard Rodabaugh & George nonlinear pressure reduction equations for in-plane closing moment are checked in a systematic study for out-of-plane moment against nonlinear finite element analysis. The results show that the pressure stiffening effects are markedly different for in-plane and out-of-plane bending.

Tension Leg Platform (TLP) adalah anjungan lepas pantai yang biasanya digunakan untuk kegiatan eksplorasi migas di laut dalam. Salah satu permasalahan yang sering terjadi adalah goncangan TLP sebagai respon terhadap gelombang laut. Pada kondisi tertentu, terutama di laut dalam samudra, goncangan ini dapat mengakibatkan berbagai gangguan, bahkan berpotensi merusak struktur. Pada artikel ini diusulkan penggunaan ponton bertelapak silinder untuk mendapatkan respon dinamis yang lebih stabil, yang selanjutnya dilakukan kaji perbandingan dengan ponton bertelapak bujur sangkar yang biasa dipakai selama ini. Respon dinamik kedua model direkam dengan sensor ultrasonic dan video tracker. Hasil pengukuran ditampilkan dalam bentuk non dimensional, yang biasa dikenal sebagai Response Amplitude Operator (RAO), yaitu rasio antara displacement TLP terhadap panjang gelombang. Dari penelitian ini didapatkan bahwa TLP dengan menggunakan ponton bertelapak silinder memiliki respon dinamik yang relative stabil jika dibandingkan dengan TLP berponton telapak bujur sangkar.