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%.

This research studied the use of carbon fiber reinforced geopolymer composites as corrosion resistant pipe material. Geopolymer material is a general term for material synthesized from fly ash. Fly ash is an industrial by-product (coal combustion residue) with high silica content (SiO2) and Alumina content (Al2O3). In addition, there are also other elements in a relatively small percentage. This material will compound like cement if activated with Sodium Silicate. This study aims to obtain the optimum composition for high quality mechanical properties. The method used is to synthesize material with various elemental compositions. Furthermore, a mechanical test (bending test) is performed to see the effect of each element to be optimized. Besides that, a physical test in the form of SEM-EDX was also conducted to see the microstructure. Materials with optimum composition have been fabricated as pipes with centrifugal casting process. Mechanical testing of pipe samples is done by hoop tensile strength test. The test results show that the strength of geopolymer composites can achieve 58 MPa.

Sebagai negara kepulauan, Indonesia memiliki potensi sumber daya laut yang besar. Potensi tersebut harus didukung dengan kajian teoritis sebagai dasar untuk pengembangan teknologi kelautan. Untuk itu pada kajian ini dibuat media gelombang skala laboratorium sebagai media pengamatan kinematika partikel air dan pendefinisian persamaan gerak gelombang. Partikel air diwakili oleh bola pelampung yang dipasang pada berbagai tingkat kedalaman. Pergerakan pelampung direkam dengan perekam video, kemudian diubah menjadi grafik perpindahan dengan aplikasi video tracker. Seperangkat pembangkit gelombang dirancang untuk mendapatkan berbagai ukuran dan jenis gelombang, yang bergerak bolak-balik dan terhubung ke rotor eksentrik dengan mekanisme engkol peluncur. Eksentrisitas rotor dapat divariasikan, pada kajian ini ditentukan e1 = 3 cm, e2 = 5 cm, dan e3 = 8 cm. Dari hasil pengujian dapat disimpulkan bahwa untuk e1 ,jenis gelombang yang terjadi sesuai dengan Persamaan Airy, sedangkan untuk e2 dan e3 diperoleh gelombang yang sesuai dengan Persamaan Stokes. Selain itu, diketahui pula perpindahan pergerakan partikel air yang terjadi maksimal di permukaan dan berkurang di level yang lebih dalam.

In the field of materials engineering, various types of advanced materials have been found. This must also be accompanied by technological advances in the production process. Centrifugal casting is an effective method for casting cylindrical objects such as pipes and pressure vessels. In this research, a centrifugal casting machine is designed and made. The design process follows the steps proposed by Pahl and Beitz, starting from requirements identification, concept design, layout and analysis to the fabrication method. Furthermore, this machine was tested for casting geopolymer composite pipes. From the test results it is stated that this machine works well and can cast pipe samples at various speeds. Furthermore, the sample is cut into a three-point bending test specimen. From the test results obtained bending strength of about 50 MPa (1500 rpm tube rotation) and about 36 MPa (1200 rpm tube rotation). Thus, it is concluded that the higher the tube rotation, the higher the quality of the resulting product.