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Analisis Komposit Serat kaca/Vinil ester terhadap Pembebanan Tekanan Internal untuk Aplikasi Tabung Gas Alam Terkompresi (Compressed Natural Gas (CNG)) Tipe IV Risa Nurin Baiti; Hosta Ardhyananta
Jurnal Teknik ITS Vol 2, No 1 (2013)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (556.602 KB) | DOI: 10.12962/j23373539.v2i1.2198

Abstract

Gas alam dalam bentuk Compressed Natural Gas (CNG) memiliki tekanan 20 MPa. Komposit serat kaca/vinil ester memiliki potensi untuk dibentuk menjadi tabung CNG. Studi ini menggunakan metode analisa numerik untuk mengkaji kemampuan komposit dalam menerima beban tekanan internal. Faktor keamanan yang digunakan adalah 1,5 sehingga nilai tekanan internal yang diaplikasikan sebesar 35 MPa. Konstanta teknik yang diinputkan pada analisa numerik diperoleh melalui pengujian tarik. Jumlah lapisan dan arah serat dipilih sebagai variabel bebas. Analisa numerik tabung CNG dilakukan dengan pendekatan tubular menggunakan program MSC Nastran. Distribusi beban pada tabung menunjukkan sudut (+50) optimal untuk diaplikasikan. Konfigurasi sudut (+70,+25)s memberikan hasil yang lebih optimum daripada penggunaan satu sudut. Jumlah lapisan minimum diperoleh dengan mengacu pada kriteria kegagalan laminat Hill. Komposit berada pada kondisi aman pada lapisan ke 180. Tetapi, komposit serat kaca/vinil ester dapat diaplikasikan pada pembuatan tabung liquified natural gas (LNG) yang bertekanan 2MPa dengan 23 lapis lamina. Sehingga, material komposit serat kaca/vinil ester tidak disarankan untuk digunakan pada pembuatan tabung CNG
Perancangan mekanisme rel torch plasma cutting 1 (satu) Axis I Wayan Suma Wibawa; I Komang Kantun; I Ketut Suherman; Risa Nurin Baiti; I Wayan Suirya
Journal of Applied Mechanical Engineering and Green Technology Vol. 3 No. 1 (2022): March 2022
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (515.479 KB) | DOI: 10.31940/jametech.v3i1.8-12

Abstract

Plasma cutting is a method of cutting metal, especially steel, with relatively low cost and effectiveness, with satisfactory results. Where in the cut, it is enough to need a plasma cutting machine/inverter that is quite affordable, widely available in the market, and simple tools, an air compressor (no special oxygen/gas needed as in gas/oxygen and acetylene/LPG cutting), a power source, the material being cut and the cutting process can be carried out. How to use plasma cutting is relatively easy, namely by setting the machine and then directing the plasma torch to the cutting plane as needed by maintaining a stable movement and height. However, when we make repeated cuts, our concentration and physical strength will automatically decrease, so we need a tool that can help us direct/adjust the plasma torch, which is called a plasma cutting mechanism. After paying attention to these needs, a plasma cutting mechanism was designed with a working space/cutting length of 1200 mm, with a tool size of 1400 mm x 300mm x 200 mm length, width and height, estimated cost of Rp. 3,050,000,-, with a cutting speed setting of 100 mm/minute to 1000 mm/minute, a cutting height of 0 to 10 mm with an angle of 0 degree to 90 degree.
Evaluation of surface properties of betung bamboo (Dendrocalmus asper) strands under various heat treatment duration and temperature Risa Nurin Baiti; Sena Maulana; Wahyu Solafide Sipahutar; Rio Ardiansyah Murda; Fajar Aditya Julyatmojo; Astri Aulia Suwanda; Muhammad Saeful Fadlan
Journal of Science and Applicative Technology Vol 5 No 2 (2021): Journal of Science and Applicative Technology December Chapter
Publisher : Lembaga Penelitian dan Pengabdian Masyarakat (LPPM), Institut Teknologi Sumatera, Lampung Selatan, Lampung, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35472/jsat.v5i2.457

Abstract

The abundance, rapid growth characteristics and good mechanical properties have made betung bamboo as good alternative materials to replace the slow growing wood. To adress the susceptibility to insects and water attack, the making of bamboo composites, using resin as matrix, has been widely practiced. Thus, the surface properties of bamboo strands are crucial to determine the optimum interaction with resin. This study evaluate the effect of heat treatment to improve the surface properties of bamboo strands, such as the wettability and the color change. Beforehand, the freshly cut bamboo was cut, cleaned and sand-grinded. The heat treatment was done at 140o and 160oC for 1, 2, and 3 hours. After cooling down to room temperature, the contact angle of bamboo’s surface was measured by sessile drop methode. The wettability was indicated by constant of contact angle change rate, K. Besides, the change of color was also determined. After the experiments, it was obtained that the bamboo surface tends to be more hydrophobic and has darker color with longer duration of heat treatment. Higher temperature and longer duration of heat treatment can cause more evaporation of liquid inside bamboo and decrease hydrophilicity of the surface.
The Effect of Reinforcement Surface Treatment With Citric Acid on The Flexural and Hardness Properties of Epoxy/Wood Sawdust Composites Asana, I Wayan Padma Yogi; Baiti, Risa Nurin; Widantha, Komang Widhi
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 25 No. 2 (2025): July
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v25i2.100-106

Abstract

This study investigates the effect of citric acid surface treatment on wood sawdust used as reinforcement in epoxy-based composites, with a focus on improving bending strength. Wood sawdust was subjected to surface modification using citric acid and sodium hydroxide (NaOH) under equivalent molar concentrations. Bending strength tests showed that both citric acid and NaOH treatments significantly improved mechanical performance compared to untreated samples, with average strengths of 33.83 MPa and 32.82 MPa, respectively, versus 21.83 MPa for the untreated group. Statistical analysis was conducted to compare the two treatments. After confirming normal distribution but unequal variances, a Welch two-sample t-test was performed, yielding a p-value of 0.742. This result indicates no statistically significant difference in bending strength between citric acid and NaOH treatments.
Mold Design for Injection Molding Machine Using Recycled Aluminum Renaldy, Amadeus; Baiti, Risa Nurin; Rahtika, I Putu Gede Sopan; Widantha, Komang Widhi
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 25 No. 1 (2025): March
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v25i1.54-60

Abstract

The use of aluminum is widely spread from beverage cans, car parts, airplanes, trains, and household furniture. This is due to its lightweight and good corrosion resistance. However, as a metal aluminum waste is difficult to be decomposed naturally. Aluminum metal takes 80 to 100 years to decompose. So the accumulation of untreated scrap aluminum can pollute the environment. One of the solutions is to recycle aluminum by melting and re-casting it into a new shape: a mold for polymer processing. The waste of beverage cans was cleaned from any dirt and adhesive. Then, they were turned into small parts by a crusher. The melting process was done at 650oC. The molten aluminum was poured into a sand mould in the shape of mould of a tensile testing specimen. The recycled product can be used to prepare tensile testing samples of polymer or polymer-based composite with injection molding technique. To evaluate the quality of recycled aluminum, a hardness test was done with a value of 69.31 + 3.02 HB. This value is lower than first-use aluminum. This is due to a combination of microstructural changes due to repeated heating, the presence of additives and impurities, and the effects of heat treatment and open cooling. Metallographic testing was carried out to evaluate the microstructure of the material resulting from the smelting of scrap aluminum using sand molds. In this test, the etching solution used consisted of 100 ml of water and 20 g of sodium hydroxide. The results of the metallographic images on the recycled aluminum material show the presence of a stand-alone silicon (Si) element and an aluminum-copper alloy (CuAl₂).
Escalation of Capacity and Quality PS60 Casting Production by Gating System Modification Primaningtyas, Widya Emilia; Purnomo, Dhika Aditya; Ariani, Silvi; Wulandari, Kiki Dwi; Alfanda, Benedicta Dian; Baiti, Risa Nurin
International Journal of Marine Engineering Innovation and Research Vol 9, No 1 (2024)
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v9i1.20125

Abstract

A ship tank’s ventilation pipes protector, called PS60, is produced by an investment casting process using CF8M material. Shorter time production for PS60 products, occurred due to the rise of PS60 demand, resulting non class casting product quality. Reported that 15% of PS60 defective products were shown from each production group. Porosity defects are the most common defects found. Recalculating riser’s, runners’s, and ingates’s dimensions, then remodeling designs a mold gating system done in order to reduce the percentage of defective products and increase production capacity. Remodeling gating system and casting simulation done by ProCast 2018 software using New Advanced Porocity Module (NAPM). The casting simulation output was porosity defects location and percentage, which were further analyzed. The product produced using a mold Gating system with a new layout, had 314.73 cm3 of empty part in the mold cavity which was identified as a porosity defect which was 4.58% of the total volume of the cast product. The total value of  the porosity after remodeling decreases by 2.39% from the existing product. 93.3% of the cavity inside the product is categorized as macroscopic porosity defects that are centralized in the riser and pouring basin areas, where in the casting product finishing process, these areas will be removed. Modification of the Gating System in PS60 mold escalates twice of PS60 capacity production than the origin.
Optimization of Pineapple Leaf Fiber-Reinforced ABS Waste Filaments for FDM: Effect of Mesh Size and Volume Fraction Sipahutar, Wahyu; Fikri, Azizul; Baiti, Risa Nurin; Siregar, Mhd Yasin; Putri, Faiza Armalia
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 25 No. 3 (2025): November
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v25i3.169-174

Abstract

Acrylonitrile Butadiene Styrene (ABS) plastic waste presents significant potential for upcycling into environmentally friendly materials, particularly as feedstock for 3D printing filaments in Fused Deposition Modeling (FDM). This study investigates the influence of pineapple leaf fiber (PALF) reinforcement at two weight fractions (3% and 5%) and two mesh sizes (200 and 300) on the dimensional stability, printability, and mechanical properties of ABS waste-based composite filaments. Comprehensive evaluations were conducted, including filament diameter consistency, surface morphology, and uniaxial tensile testing. The 5% fiber content with 300-mesh PALF yielded the most stable filament diameter (average 1.73 mm, CV 2%), while the same formulation also achieved the highest ultimate tensile strength (UTS) of 8.873 MPa and elongation at break of 0.197%. Interestingly, the highest Young’s modulus (0.139 GPa) was observed in the 3%–300 mesh variant, although it exhibited more brittle behavior. Overall, the 5%–300 mesh formulation was identified as optimal, striking a favorable balance between tensile strength, flexibility, and dimensional consistency, thereby validating its suitability as a sustainable FDM filament derived from post-consumer ABS waste.