ABSTRAKPlastik merupakan material yang susah terurai sehingga perlu diadakan penelitian tentang pemanfatan sampah plastic yang ada di sekitar kita, uji impak pada plastik sampah daur ulang ini bertujuan untuk mengetahui sifat fisik,keuletan,ketangguhan dari plastik sampah duar ulang. Spesimen uji impak berdasarkan sampel standar (ASTM E-23) yaitu batang uji Charpy memiliki dimensi ukuran yaitu 10 x 10 x 100 mm (tinggi x lebar x panjang). Dengan posisi takik (notch) berada di tengah, dengan bentuk takikan huruf V, kedalaman takik 2mm dari permukaan benda uji dan sudut takik 45 º. Spesimen dibuat sesuai sampel dengan pengujian dilakukan sebanyak 10 kali,dengan hasil nilai ratarata specimen adalah plastik jenis polypropylene nilai mean energy impaknya = 1,31 joule dan nilai mean kekuatan impak / impact strength nya = 0,0161 joule/mm². plastik jenis Polyethylene Terephthalate nilai mean energy impaknya = 1,15 joule dan nilai mean kekuatan impak/ impact strength nya = 0,0138 joule/mm², plastik campuran antara PP dan PET nilai mean energy impaknya = 1,18 joule dan nilai mean kekuatan impak / impact strengthnya = 0,0145 joule/mm². Hasil pengujian ini plastik Polypropelin mempunyai nilai harga impak tertinggi untuk plastik sampah daur ulang.Kata kunci: plastik sampah, luas penampang, energi impak, kekuatan impak. ABSTRACT Material Plastic is difficult to decompose, so it needs to be held research on utilization of plastic waste that is around us. Impact test on recycled plastic waste aims to find out the physical properties, tenacity, toughness of plastic waste re-rubbish. Specimens of impact test based on standard sample (ASTM E-23) with Charpy test rod has dimension of size is 10 x 10 x 100 mm (height x width x length). With the notch position in the center

Good acceleration and performance are influenced by the degree of flexibility of the clutch springs. The objective that underlies the implementation of this study is to determine the effect of replacing the clutch spring with different length variations. In this study, the data taken is the torque, power and fuel consumption of each type of clutch spring. In this test, two types of clutch springs were used, namely the standard clutch spring and the TDR type coupling spring which were varied in length (38.31mm), (40.93mm) with the addition of 2mm (42.93mm), (40.31mm) rings. also cutting thread 2mm (38.93mm), (36.31mm). Tests were carried out using a dynotest tool with an engine speed of 4000 rpm to 9000 rpm transmission position six. In the TDR clutch spring (42.93mm) there is an increase in torque of 7.42% with a torque yield of 16.20 Nm at 6000 rpm and an increase in power of 6.61% with a power yield of 14.5 HP at 7000 rpm. For fuel consumption TDR coupling spring at ideal rotation (low-medium), an increase of 9.68%. The decrease in fuel consumption only occurred at the top / high speed of 6.32%. For the test results pertalite ethanol fuel, there is a decrease in fuel consumption compared to pertalite fuel for all RPM variables

TiAl alloys can be used in aircraft and high-performance vehicle engines owing to their structural stability at high temperatures and their light weight. Although many studies have focused on developing this alloy material, there is still a lack of information about the changes in the structure of TiAl alloys under tensile and compressive loading. Therefore, we performed molecular dynamics simulations of the tensile and compressive loading of TiAl alloys in the <001> direction at temperatures of 10 and 300 K. From our simulation results, we found that the tensile and compressive strengths of TiAl alloys are significantly affected by temperature. It was found that TiAl alloys can withstand greater compression loading than tensile loading. This is due to the change in the crystal structure of TiAl alloys after being deformed to a strain of 0.4 by compressive loading, according to the analysis of structural changes under loading conditions. From the radial distribution analysis results, there was a change in the orientation of the face-centered cubic-like structure as it reached the maximum compressive stress compared to the initial structure.

Cemented carbides are joined with steel to be used as a cutting tool. Brazing is one of a method joinning metals that has the potential to combine different types of materials such as cemented carbide and steel. This study aimed to investigate the effect of heat treatment on the microstructure and the distribution of the hardness value brazed joint between cemented carbide and carbon steel. The heat treatment was carried out at a temperature of 700oC, 725oC, and 750oC for 30 minutes. The joint area is observed using SEM  equipped with EDS. The distribution of hardness value ​​was tested using a micro    vickers testing machine. Microstructure observations and SEM-EDS analysis show that the junction region consists of 3 parts, part I is the phase of Cu solution enriched solid, part II phase of the solid solution with the highest percentage of Ag, and part III is the eutectic phase of Ag-Cu-Zn . EDS test results in each section show that the value of element C increases when the treatment temperature is increased. The hardness test results show that the distribution of the hardness value increases when the treatment temperature is added. The hardness of the test specimen without treatment reached 112.73 VHN. The highest hardness value is 131.88 VHN at 750oC. Thus the heat treatment affects the microstructure and the rate of diffusion of metal elements. The higher the temperature, the diffusion rate of the metal element increases, so that it affects mechanical.

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