https://journal2.ummat.ac.id/index.php/protech <p>Protech Biosystems Journal is a peer-refereed open-access journal which has been established for the dissemination of state-of-the-art knowledge in the field of Agricultural Enginering (Agricultural Mechanization, waters and land resources Engineering, Energy, Bioprocess and Postharvest Technology) and related subjects in this field. All submitted manuscripts will be initially reviewed by editors and are then evaluated by a minimum of two reviewers through the double-blind review process. This is to ensure the quality of the published manuscripts in the journal. Protech Biosystems Journal is a journal published by the Agricultural Enggineering Departement of Agriculture Faculty of Muhammadiyah University of Mataram. Protech Biosystems Journal invites scientists and engineers throughout the world to exchange and disseminate theoretical and practice-oriented the whole aspect of Agricultural Enginering and Biosystems and related subjects in this field including: 1. Agricultural mechanization, 2. Waters and land resources engineering, 3. Energy, 4. Bioprocess, and 5. Postharvest technology</p> Universitas Muhammadiyah Mataram en-US Protech Biosystems Journal 2809-4425 https://journal2.ummat.ac.id/index.php/protech/article/view/28 <p><em>This study analyze the effect of fiber volume fraction variation of elephant grass fibers on the tensile strength properties of polyester resin matrix composites. The research was conducted in five stages: fiber extraction, alkaline treatment using a 1% NaOH solution, composite fabrication with polyester resin at a ratio of 2% of resin volume, SEM analysis, and tensile strength testing. The highest tensile strength (21,934 MPa) was obtained at a fiber-resin ratio of 10/90. Variation of fiber 5/95, tensile strength of (21.737 Mpa), modulus of elasticity of (1776.9 MPa) and elongation of (2.1788 mm), shows the dominance of the resin matrix in supporting loads. Fiber variation of 20/80, decrease in tensile strength to (21.169 MPa) and elongation of (2.2255 mm) due to uneven resin distribution. The most significant decrease occurred in the 30/70 fiber variation, the total tensile strength was (18.833 Mpa), the modulus of elasticity was (1390.3 MPa), although the elongation increased to (2.606 mm). Increased elongation indicates weak interface bonds due to fiber agglomeration and increased void, making the composite more susceptible to deformation before breaking. The SEM results support the tensile test results, where the 10/90 variation, shows the most homogeneous structure with good fiber distribution and minimal void count. Overall, the composition of fiber and 10/90 resin is concluded to be the most optimal composition because it provides the best balance between tensile strength, rigidity, and deformation ability of the material.</em></p> Purna Putrawan Nasmi Herlina Sari Salman Salman Copyright (c) 2026 Protech Biosystems Journal 2026-04-13 2026-04-13 6 1 1 12