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Aluminium-particulate glass matrices composites generally use the pressure in the making of green parts/green specimens before heating at sintering temperature.The purpose of this research is to develop the glass composites that it can be used as a material for indirect layer manufacturing, especially used for making plastic injection mold/insert mold. To achieve these goals, the flexural strength and dimensional errors were studied.Starting materials consist of the mixture of glass powders, aluminium powders, and acrylic powders in the volume ratio of 1 : 1 : 1. The glass powders and aluminium powders wererecovered from waste materials. The size of acrylics and glass particles was lower than 0.074 mm and aluminium particles size was lower than 0.297 mm respectively. Green specimens were made by using indirect layer manufacturing processes, while sintered specimens obtained by heating the green specimens in a furnace at a temperature of 700°C for 1 hour. Finished specimens were made by impregnation process of sintered specimens using epoxy resin.The bending strength of green specimens, sintered specimens, and finished specimens is 20 kg/cm2, 80 kg/cm2, and 170 kg/cm2 respectively. Maximum dimensional error of green specimens and sintered specimens is 50% and 40% respectively. Insert mold made by indirect layer manufacturing is broken after producing as many as 120 pieces of plastic products.Keywords: glass matrix composite, insert mold, dimensional error, bending strength.

Vortex turbine is the one of turbines which meets those criteria. This turbine utilizes kinetic energy of vortex water and converts it into a shaft power. The objectives of this research were to obtain the torque that could be generated from the vortex turbine by varying the width of turbine blades and to know the output power also the optimum efficiency obtained from this variation. This research was conducted by using vortex pool in a laboratory scale with a diameter of 108 cm and 6 turbine blades on permanent rotation at 50 rpm, 60 rpm, and 70 rpm. Turbine blades were made from flat rectangular steel with a length of 40 cm sized 1/6, 2/6, 3/6, 4/6 and 5/6 times to radius of vortex pool.The results of the research showed the torque as 1.40 Nm at rotation is 50 rpm. The maximum power is obtained from blade with width of 3/6 times radius of the pool, that is 8.60 Watts at head 0.362 m and discharge 11.83 l/s or 0.01183 m3/s at rotaion shaft is 70 rpm. This experiment also generated and turbine efficiency of 16.46% at rotation of shaft is 70 rpm.

In the plan electric power system, system of generating and transmission systems system interact economically in selecting location, design and economic scale relation. Transmission of power in the distribution system was likely through air or underground pipes. The selection on the pipes depended on several different factors; those were factors of continuity on service, region development direction, maintenance costs, capital cost and age of system usage. Result of feasibility study and scheme of network PLTMH in Oesusu Village, Takari Subdistrict, Kupang Regency, East Nusa Tenggara Province for the requirement of 90 consumers require the energy 11.25 kVA. While result of energy planning awakened from existed power of PLTMH equal to 30 kVA. Based on geographic location and situation that not wide enough, subsequently it was selected a system; a radial secondary distribution network system (air pipes). Results of the research were expected to be provided any solutions generally for the Local Government spescally in rural or purilieus in overcoming electricity deficit that happenend, especially in its distribution network system.

Besi cor kelabu adalah material yang murah dan cukup kuat serta mempunyai sifat redaman getaran yang cukup baik. Sifat ini dimiliki karena adanya grafit serpih yang tersusun dari atomatom karbon. Struktur mikro yang demikian dipenuhi bila unsur-unsur yang terkandung di dalamnya memenuhi syarat yaitu prosentase karbon jenuh (Sc) dan kecepatan pendinginan yang sesuai.. Bila kecepatan pendinginan terlalu besar akibat tebal coran yang terlalu kecil, maka grafit serpih tidak terbentuk dan akan berubah menjadi besi cor putih yang keras dan getas serta redaman yang jelek terhadap getaran. Pada penelitian ini penulis mengamati pengaruh pendinginan yang berbeda akibat tebal coran yang berbeda pada besi cor. Agar penelitian berlangsung sederhana dan memenuhi tujuan dari penelitian itu sendiri, maka penulis menggunakan cetakan pasir yang mempunyai rongga berbentuk tirus dengan ukuran lebar 15mm, tinggi 75mm, dan panjang 150mm. Cairan besi cor kelabu dituangkan ke dalam cetakan tersebut dan dibiarkan membeku serta mendingin. Setelah diadakan pengujian struktur mikro pada potongan penampangnya, maka nampak pada bagian yang tebalnya 0,5 mm atau kurang (ujung lancip, yaitu bagian yang mana terjadi pendinginan cepat) besi cor kelabu berubah menjadi besi cor putih yang keras dan getas, sedangkan bagian yang tebalnya lebih dari 0,5 mm grafit mulai terbentuk. Terbentuknya grafit berarti besi cor kelabu mulai terbentuk. Selanjutnya dengan melakukan pengujian kekerasan, didapat data pada bagian yang tebalnya 0,5mm kekerasan rata-rata 22 HRC sampai dengan 47,75 HRC, sedangkan pada bagian yang tebalnya 13mm kekerasannya antara 9,5 HRC sampai dengan 13,25 HRC. Dari hasil penelitian ini, maka ketebalan coran pada benda dari besi cor kelabu harus bisa dijamin bahwa struktur mikronya tetap besi cor kelabu. Keywords: Besi cor kelabu, grafit serpih, besi cor putih, tebal coran

Metal matrix composites can be produced by powder metallurgy (P/M). Product of P/M generally contains porosity that affects physical and mechanical properties. The aim of this research is to investigate the effect of temperature variation on compacted and graphite addition on the physical and mechanical properties of Al-Si/C composites. The materials in this research were Al-Si as the matrix and graphite powder as the reinforcement. The content of reinforcement were 0 and 2.5 wt% of graphite. Powder was compacted 400 MPa at 150o C, 200o C and 250o C. The green bodies were sintered at 500 oC for 2 hours. Physical and mechanical properties of Al-Si/C composites were tested by Brinnel hardness, optical microscopic and density. Results of the research show that the addition of graphite up to 2.5 wt% and increasing compacted temperature increases the hardness and density of Al-Si/C composites. Hardness and density of a specimen containing 2.5 wt% graphite which is compacted 250o C are 49 VHN and 2.7 gr/cm3 respectively whereas a graphite-free specimen compacted at 250o C has hardness of 48 VHN and density of 2.68 gr/cm3. Keywords : Uniaxial hot pressing, graphite, composite