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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.
Pemanfaatan Limbah Cangkang Kerang untuk Produksi Pupuk Organik Cair: Studi Kasus Desa Mojoasem, Sidayu, Gresik Ananda, Muhammad Bagas; Rasyida, Amaliya; Pintowantoro, Sungging; Setiyorini, Yuli; Pradesar, Yusuf; Pramadewandaru, Respati Kevin
Sewagati Vol 9 No 2 (2025)
Publisher : Pusat Publikasi ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j26139960.v9i2.2508

Abstract

Pengelolaan limbah perikanan, khususnya limbah cangkang kerang, merupakan tantangan lingkungan yang signifikan di Mojoasem, Sidayu, Gresik. Pengabdian masyarakat ini bertujuan untuk memberikan pelatihan dan inisiasi pembentukan startup untuk memproses limbah tersebut menjadi pupuk organik cair (POC) guna meningkatkan partisipasi masyarakat dalam pengelolaan sampah organik. Metode yang diterapkan meliputi sosialisasi mengenai dampak lingkungan limbah perikanan, pelatihan proses fermentasi limbah menggunakan bioaktivator alami seperti EM4 dan molase, serta praktik langsung produksi POC. Masyarakat menunjukkan partisipasi aktif dengan antusias bertanya dan berdiskusi terkait proses produksi dan potensi pemasaran POC. Signifikansi dari hasil ini adalah potensi pengurangan limbah organik serta peningkatan pendapatan masyarakat melalui produk lokal. Proyek ini berpotensi memberikan solusi berkelanjutan untuk masalah limbah organik sekaligus memperkuat ekonomi desa Mojoasem.
A CRITICAL REVIEW ON FATIGUE ASSESSMENT APPROACH IN SHIP STRUCTURAL DETAILS Ariesta, Rizky Chandra; Frestiqauli, Santi; Safa’at, Ahmat; Pradesar, Yusuf; Kallur, Abhishek
Journal of Marine-Earth Science and Technology Vol. 5 No. 1 (2024): April
Publisher : Marine & Earth Science and Technology Research Center, DRPM, ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j27745449.v5i1.1066

Abstract

Review of the methods used in the fatigue analysis of structures has been widely used. The resulting fatigue is primarily the result of repeated loads acting on the structure both internally and externally. Internal loads are caused by the cargo loading and unloading process, while external loads are caused by sea waves. The interaction of the two loads affects the strength of the structure. In this paper, we will discuss materials, residual stresses and environmental factors that cause fatigue in structures. The focus of analysis in this critical review is on the structural details of the ship. In determining fatigue in detailed structures, it can occur in welded joints, section cuts and shape imperfections.
ELECTROCHEMICAL PERFORMANCES OF NITROGEN-DOPED CARBON/MNO2 COMPOSITE SUPERCAPACITOR ELECTRODE IN KI-ADDED NA2SO4 ELECTROLYTE Sutarsis, Sutarsis; Abyan, Demas Muhammad; Kussuma, Fahrul Ardian Firmanda; Pradesar, Yusuf; Purniawan, Agung
Jurnal Dinamika Vokasional Teknik Mesin Vol. 9 No. 2 (2024)
Publisher : Department of Mechanical Engineering Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/dinamika.v9i2.77816

Abstract

In this study, Nitrogen-doped Activated Carbons (NAC) with different Nitrogen concentrations (NAC1, NAC2, NAC3) and Manganese Dioxide (MnO2) were composited to make the hybrid active material for supercapacitor electrodes to improve the energy density of NAC by adding the pseudo-redox capacitive properties of NAC/MnO2 composite electrode. NAC active material was made from the pyrolyzing biomass carbon and Polyaniline mixture at 800 °C in a nitrogen atmosphere for 2 hours. NAC/MnO2 hybrid material was synthesized by heating NAC: MnO2 with a ratio of 5:1 at 400 °C for 2 hours. Peaks analysis of X-ray diffraction of NAC/MnO2 powder shows that the MnO2 phase was formed as a composite with NAC. The electrochemical performance of the NAC3/MnO2 electrode exhibited the highest capacitance of 168 Fg-1 at a scan rate of 5 mVs-1 in Potassium Iodide (KI)-added Na2SO4 electrolyte. According to the Cycle Voltammetry (CV) measurement, the NAC3/MNO2 composite electrode shows hybrid capacitive behavior consisting of pseudo-redox and double-layer electrostatic energy storage mechanisms in KI-added Na2SO4 electrolyte. NAC3/MnO2 composite electrode demonstrates a high energy density of 22 Whkg-1 at 5 mVs-1.