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The Effect of Aggregate Size and Resin Fraction on The Damping Capacity of Epoxy-Marble Composite Hermana, Gita Novian; Kusnowo, Roni; Purwadi, Wiwik; Pradesar, Yusuf
Jurnal Bahan Alam Terbarukan Vol 10, No 2 (2021): December 2021 [Nationally Accredited - Sinta 2]
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jbat.v10i2.34070

Abstract

The production of material with high precission and high complexity has been rapidly increasing in several industrial sector. The high accuracy is difficult to achieve during manufacturing due to vibration factors that influenced the final product of material. In this study the relationship between particle size and percentage of marble aggregate with epoxy resin on damping capacity was studied systematically. The Composite materials were fabricated by using conventional casting technique with 10, 25, and 50% volume fraction of resin and two marble aggregate groups with 0.5-0.7 mm and 1.4-2.0 mm in particle size. The casting process was using multilayer pouring technologies to prevent void formation. 10% epoxy resin-fine marble aggregate has very good vibration result with 0.003 mm in displacement, 0.23 mm/s in velocity, and 0.2 m/s2 in acceleration. The 10% epoxy resin-fine marble aggregate also has the best damping ratio among the composite due to the large specific area and porosity inside the marble material with value of 0.5%. The multilayer pour techniques for composite has been successfully adapted in this study to minimalize void/bubble formation inside and upperside of epoxy resin during the fabrication of composite. The secondary electron image of composite was observed that the marble aggregates and epoxy resin bonding are very good and no crack or void formation in the interface of the marble aggregate and epoxy resin.
Kompaksi Terhadap Densitas Dan Kekerasan Pada Komposit W-Cu Untuk Proyektil Peluru Dengan Proses Metalurgi Serbuk Gita Novian Hermana; Widyastuti Widyastuti
Jurnal Teknik ITS Vol 3, No 1 (2014)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (645.875 KB) | DOI: 10.12962/j23373539.v3i1.5857

Abstract

Dalam penggunaanya peluru memiliki beberapa bagian yaitu proyektil (bullet), kelongsong (bullet base), mesiu (propellant), dan pematik (rim). Proyektil menjadi penting karena proyektil adalah bagian yang menuju sasaran untuk menembus atau melumpuhkan. Bagian proyektil pada umumnya terbuat dari material yang berat jenisnya relatif tinggi, sehingga mampu menghasilkan peluru yang memiliki momentum yang besar dan jangkauan yang lebih jauh. Tungsten dipilih sebagai pengganti timbal karena tungsten memiliki densitas lebih besar dari timbal dan juga tidak memiliki sifat racun terhadap manusia. Proses pembuatannya melalui proses metalurgi serbuk dengan komposisi tembaga sebanyak 20, 30, 40 wt% dan tekanan kompaksi sebesar 200, 400, dan 600 MPa. Kemudian dilakukan sintering pada temperatur 900oC selama 1 jam. Hasil terbaik didapatkan pada W-20wt%Cu dengan nilai green density dan sinter density sebesar 12,09 g/cm3 dan 14,14 g/cm3 serta memiliki kekerasan, compressive strength, dan modulus elastisitas sebesar 32 HRB, 220,89 MPa dan 55,68 GPa
The Calculation of Ni-Sn-W Alloy Phase Diagram Using CALPHAD Method As New Soldering Material Riswan Eko Susanto; Gita Novian Hermana
International Journal of Science, Engineering, and Information Technology Vol 4, No 1 (2019): IJSEIT Volume. 04 Issue. 01 DECEMBER 2019
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (317.878 KB) | DOI: 10.21107/ijseit.v4i1.6557

Abstract

The Ni-Sn-W Alloy becomes an alternative as the Ni element could slow and block the forming of intermetalic. Beside, the existence of the W element could add the solder materials performance which is able to block the forming of intermetalic substance. Calculation of phase diagram (CALPHAD) is able to become a solution for the limited information about phase diagram whether two system (biner) or others systems above. Computing method of CALPHAD used the factual approach and assumed that it is the characteristic of thermodynamic. From the calculation, the result gained are Ni3Sn, Ni3Sn2, Ni3Sn4, solidus Sn (Sn), solidus Ni (Ni), NiW, Ni4W, solidus  W (W), and solidus  liquid (L).  
Stokes' Law Approach to Slag Formation Process to Increase the Effectiveness of Cleaning Metal Liquids in Cast Iron Smelting Process Muhammad Rizki Gorbyandi Nadi; Cecep Ruskandi; Ari Siswanto; Gita Novian Hermana
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.14502

Abstract

The purpose of this study was to increase the effectiveness of slag cleaning in the cast iron smelting process using an induction furnace. This study resulted in the calculation of the terminal velocity of the slag emerging to the surface of the induction furnace based on Stokes' Law approach for each slag that appears during the cast iron smelting process. For each cast iron casting, three samples were taken based on the fastest time on the very light slag, the slag’s time for the heaviest slag, and the extreme time for comparison. The results of each sample are tested for characterization such as shape, size, and chemical composition of each sample which are then adjusted to the calculations that have been made. The characterization was analyzed using X-ray diffraction, scanning electroscope, and energy dispersive spectroscopy microanalysis. The results show that the Stokes law approach to predict the slag reaching the surface gets the appropriate result that all the slag reaches the surface at time t = 230 s. The slag that appears at time t = 300 s is the slag formed due to the interaction of the liquid with the surface which is not the slag that occurs from the raw material used. This study succeeded in minimizing the formation of slag in each casting of cast iron using an induction furnace.
New Thermal Insulation Materials Based on Mahogany Sawdust and Polyurethane Foam for Buildings Gita Novian Hermana; M. Rizki Gorbyandi Nadi; M. Nur Hidajatullah; M. Nursyam Rizal
Jurnal Bahan Alam Terbarukan Vol 12, No 1 (2023): June 2023 [Nationally Accredited - Sinta 2]
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jbat.v12i1.40569

Abstract

Global energy consumption has increased in the last few decades and is the third largest contributor to global energy consumption and one of the causes of increased carbon dioxide emissions. Therefore, in this study utilizing sawdust mahogany as a thermal insulation material to overcome the above problems. Sawdust material is combined with polyurethane foam to produce optimal physical, mechanical, and thermal insulation properties. From the study results it was found that the density of the thermal insulation material increased with the addition of sawdust. The value of the density is in the range of 0.041-0.052 gr/cm3. Observations using the secondary electron image (SEI) on thermal insulation materials show that the amount of sawdust added will affect the formation of an open pore cell structure which is directly proportional to the addition of sawdust. In addition, the more sawdust that is added will change the arrangement of cells and reduce the mechanical properties of the thermal insulation material. This is confirmed by the results of the hardness test which decreases with the addition of sawdust with the lowest value of 16.6 shore C for the addition of 10% sawdust. The thermal conductivity of the thermal insulation material has a value of 0.052, 0.038, 0.033, 0.032, and 0.033 W/mK for the addition of 0.2.5%, 5%, 7.5% and 10% sawdust, respectively. This shows that the thermal insulation material made in this study can be used as an alternative to thermal insulation material
Co-Authors Ari Siswanto Cecep Ruskandi Kusnowo, Roni M. Nur Hidajatullah M. Nursyam Rizal M. Rizki Gorbyandi Nadi Muhammad Rizki Gorbyandi Nadi Pradesar, Yusuf Purwadi, Wiwik Riswan Eko Wahyu Susanto Widyastuti Widyastuti