This paper presents flexural and tensile properties of sugar palm (Arenga pinnata) fibres-reinforced polyester composites study. The fibres were treated by alkaline solution with 5% NaOH solution for 2 hours of soaking time. The composites were prepared with different orientations of fibres (i.e. 0° + 45°, 0° + 90°, 45° + 90°, and 45° + (-45°)), while the ratio between Arenga pinnata fibres and polyester is 30 percent volume. Hand lay-up method was employed to produce the specimens. ASTM D-790 03 and ASTM D-3039 standard were employed to characterize the specimens in good sequent. As the result, the specimen with 45°+90° orientation generated maximum important values both in flexural strength (24.03 MPa) and modulus (4.01 GPa), tensile strength (23.84 MPa) and modulus elasticity (0.97 GPa). This is due to palm fibres as reinforcement that forms an angle of 90 ° or increasingly upright to the load crossing field (load of bending) and tensile load giving the effect of maximum reinforcement compared to other fibres orientations.
<p>The thermal shock behavior of ceramic refractory materials is of particular interest. Refractory materials are submitted to local temperature gradients in service that originate thermal stresses and thermal shock damage to the material. However, thermal shock treatment on the refractory made from evaporation boat waste is not well documented. The purpose of this study is to determine the effect of thermal shock on the strength of refractory with various compositions. In this study, the refractory was made using 100% refractory cement (sample 1). For Sample 2, the refractory was made from a mixture of refactory cement and evaporation boats waste, each of 50%: 50%. Meanwhile, specimen 3 of the refractory is made from a mixture of refactory cement, evaporation boat waste, and silica sand of 40%: 50%: 10%, respectively. The Thermal shock treatment is carried out at a temperature range of 100 – 700<sup>o</sup>C for each specimen. The effect of thermal shock treatment on the mechanical properties of each refractory specimen was investigated using the impact and macrography test. Temperature variations in thermal shock have different effects on the level of impact strength on impact test specimens. The lowest strength was 0,012297735 J/mm<sup>2 </sup>at thermal shock 700<sup>0</sup>C in sample 3, and the highest impact strength was 0,03928934 J/mm<sup>2</sup> at 400<sup>o</sup>C thermal shock temperature in sample 2. The macrographic examination shows the higher the thermal shock temperature, the greater the fracture produced when the impact test is carried out. This is because the hardness of the refractory material increases.</p>
The purpose of this study was to determine the effect of thermal shock and composition of graphite, kaolin (clay) on the macrostructure and impact resistance of crucible based on the waste of evaporation boats. The variation applied was composition waste of evaporation boats, graphite and kaolin 50%:25%:25%; 40%:30%:30%; 70%:15%:15%. Then the thermal shock standard temperature variation is ∆T = 100°C-500°C. Specimens formed according to the ASTM D256 size (63.5x12.7x12.7) mm with compaction load 80 kg/cm 2. Continuing the sintering process at a temperature of 1150°C holding time of 2 hours. Tests include XRD test for the waste of evaporation boats, thermal shock test, impact test and macro photo. The results showed that the highest average impact resistance is 0.01772659 Joule/mm 2 with the composition of 50%: 25%: 25% without thermal shock. The lowest average resistance impact is 0.00637474 Joule/mm 2 with the composition of 70%: 15%: 15% and 500°C thermal shock temperature. Based on the data, the higher treatment of temperature in thermal shock makes the lower impact resistance of the specimen.
The purpose of this study is to synthesize and characterize of iron sand from the south coastal area of Purworejo, Central Java. Iron sand was mechanically filtered using permanent magnets 35 times. The filtered iron sand was characterized using x-ray diffraction (XRD) to determine the compound contained therein and his physical characteristics. The filtered iron sand was heated at temperatures of 800 ° C and 900 ° C for 5 hours in the furnace and after it was cold and followed by XRD testing. Based on the x-ray diffraction pattern, a single phase Fe2 O3 as a permanent magnet base can be formed after a 900 ° C heating process for 5 hours.
Proses pencampuran perlu dilakukan untuk mencegah terjadinya agglomeration sehingga dapat meningkatkan kualiatas dari produk crucible. Pencampuran adalah proses mencampurkan satu atau lebih bahan dengan menambahkan satu bahan ke bahan lainnya sehingga membuat suatu bentuk yang seragam. Oleh sebab itu, diperlukan suatu kajian untuk mengetahui pengaruh durasi pencampuran terhadap sifat mekanik pada material crucible yang dihasilkan. Spesimen crucible dibuat dengan mencampurkan semen tahan api, limbah evaporation boats, dan kaolin dengan komposisi tertentu. Proses pencampuran bahan dilakukan selama 30, 60 dan 90 menit dengan penambahan air sebanyak 15% dari total berat material. Proses kompaksi dilakukan dengan tekanan sebesar 40 kg/cm . Spesimen yang terbentuk didiamkan pada suhu 30°C selama 7 hari sebelum di sintering. Proses sintering dilakukan pada suhu 1000°C selama 2 jam menggunakan furnace untuk menghasilkan produk akhir. Proses karakterisasi pada penelitian ini menggunakan pengujian kekerasan dan foto makro. Hasil penelitian ini menunjukan spesimen dengan durasi mixing yang paling lama (90 menit) memiliki kekersan yang paling tinggi dikarenakan campuran bahan yang dihasilkan lebih homogen dibandingkan spesimen yang lain.
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