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All Journal Logic : Jurnal Rancang Bangun Dan Teknologi Frontier Advances in Applied Science and Engineering
Widantha, Komang Widhi
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Aerospace Engineering Agriculture, Biological Sciences & Forestry Astronomy Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Medicine & Pharmacology Physics

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INVESTIGATION OF TEMPERATURES AND HOLDING TIMES ON HIGH-STRENGTH LOW-ALLOY STEEL FOR TANK TRACK LINKS Selly Septianissa; Widantha, Komang Widhi; Waldi, Muhamad
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 24 No. 2 (2024): July
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v24i2.87-92

Abstract

In Indonesia, the reliance on foreign countries for military components persists, including tank track links which are crucial for combat vehicles. These components require mechanical properties such as wear resistance and toughness to ensure high safety standards. High Strength Low Alloy (HSLA) steel is used, necessitating precise composition and appropriate heat treatment processes. This study varied compositions and heat treatments to achieve desired properties, producing prototypes with five predetermined compositions. The heat treatment process involves initially heating the samples to 860°C for 30 minutes for uniformity, followed by various treatments including quenching in oil, normalizing, and multiple cycles of quenching with tempering at different temperatures and durations to refine microstructure and adjust hardness of the alloy. Results showed optimal mechanical properties in composition no. 4 after normalizing with a blower, achieving a hardness of 31 HRC. This research aimed to optimize mechanical performance during operational conditions through variations in temperatures and holding times.
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.
Immersion Behavior Study of Hydroxyapatite Scaffolds Derived from Bovine Sources In Acidic, Basic, and Neutral Solutions Widantha, Komang Widhi
Frontier Advances in Applied Science and Engineering Vol. 2 No. 1 (2024)
Publisher : Tinta Emas Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59535/faase.v2i1.296

Abstract

This research investigates the effects of particle size and compaction pressure on the dissolution behavior of hydroxyapatite scaffolds synthesized from bovine bone in acidic neutral and basic solutions. Hydroxyapatite was extracted through a process involving cutting, cleaning, boiling, soaking in NaOH, sun drying, grinding into powder and calcination at 800°C. The powder was then sieved into two size fractions (75 and 150 microns) and compacted at pressures of 200, 250, and 300 MPa. The mass and dimensions of the scaffolds were measured to calculate porosity, followed by immersion in the respective solutions for 24 hours to determine dissolution rates. Results indicated that smaller particle sizes and higher compaction pressures resulted in reduced porosity and enhanced structural integrity. The dissolution rates varied significantly with pH levels, exhibiting the highest rates in acidic conditions up to 215.83 mg/cm2 and the lowest in basic solutions up to 11.32 mg/cm2. Additionally, scaffolds with smaller particles and higher compaction pressures demonstrated lower dissolution rates across all pH levels due to lower porosity. In conclusion, both particle size and compaction pressure are critical factors influencing the dissolution behavior of hydroxyapatite scaffolds. These findings have significant implications for the design and optimization of hydroxyapatite-based materials for biomedical applications, where controlled dissolution rates are crucial for performance and longevity.
INVESTIGATION OF TEMPERATURES AND HOLDING TIMES ON HIGH-STRENGTH LOW-ALLOY STEEL FOR TANK TRACK LINKS Selly Septianissa; Widantha, Komang Widhi; Waldi, Muhamad
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 24 No. 2 (2024): July
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v24i2.87-92

Abstract

In Indonesia, the reliance on foreign countries for military components persists, including tank track links which are crucial for combat vehicles. These components require mechanical properties such as wear resistance and toughness to ensure high safety standards. High Strength Low Alloy (HSLA) steel is used, necessitating precise composition and appropriate heat treatment processes. This study varied compositions and heat treatments to achieve desired properties, producing prototypes with five predetermined compositions. The heat treatment process involves initially heating the samples to 860°C for 30 minutes for uniformity, followed by various treatments including quenching in oil, normalizing, and multiple cycles of quenching with tempering at different temperatures and durations to refine microstructure and adjust hardness of the alloy. Results showed optimal mechanical properties in composition no. 4 after normalizing with a blower, achieving a hardness of 31 HRC. This research aimed to optimize mechanical performance during operational conditions through variations in temperatures and holding times.
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).
Co-Authors Asana, I Wayan Padma Yogi Baiti, Risa Nurin I Putu Gede Sopan Rahtika Renaldy, Amadeus Risa Nurin Baiti Selly Septianissa Waldi, Muhamad