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Landslide Analysis Using Seismic Refraction Tomography And MASW: a Case Study in Ponorogo, East Java, Indonesia Yusri Prayitna; Widya Utama; Dwa Desa Warnana
IPTEK The Journal of Engineering Vol 5, No 2 (2019)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j23378557.v5i2.a5025

Abstract

Ponorogo district morphology form consisting of highlands and hills make this area vulnerable to landslides. Based on the BNPB (National Disaster Management Agency) data from 2013 to 2017, 77 landslides and 35% have occurred in Ngrayun and Slahung sub-districts. One area that has the potential to experience landslides is Tugurejo village in Slahung District. This study aims to determine the physical properties of subsurface rocks using SRT (Seismic Refraction Tomography) and MASW (Multi-channel Analysis of Surface Waves). The seismic velocity distribution defined from the SRT and MASW at the study sites shows a zone with a higher porosity that is interpreted to represent the level and depth of rock mass movement. P-wave velocity and S-wave indicates very low velocity of 500 – 1200 m/s and 100 – 250 m/s at depths up to 5 m.
Karakterisasi Fe₂O₃ Hasil Sintesis Hijau Menggunakan Ekstrak Buah Dengen (Dillenia serrata): Characterization of Fe₂O₃ from Green Synthesis Using Dengen Fruit Extract (Dillenia serrata) Nurmalasari; Nurhalima; Suaedi; Bakri, Suriyanto; Putri, Syukrika; Prayitna, Yusri
Journal of Engineering Science and Technology Applications Vol. 2 No. 2 (2024): Journal of Engineering Science and Technology Applications
Publisher : CV Insight Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58227/jesta.v2i2.204

Abstract

Fe₂O₃ has many functions, including as a pigment and as a semi-conductor material. The use of this material depends on its characteristics. In this study, the characterization of Fe₂O₃ nanoparticles produced from green synthesis was carried out. Dengen fruit extract was used as a chelating agent with iron sand raw material from the Pajallesang River, Palopo City. The synthesis was carried out using the sol-gel method at pH 4.7. The gel sample was calcined at temperatures of 600°C, 700°C, and 800°C, after which it was characterized using XRD and XRF. The average crystallite size of Fe₂O₃ particles in iron sand and after being synthesized at temperatures of 600°C, 700°C, and 800°C were respectively 40.09 nm, 36.67 nm, 31.46 nm, and 69.04 nm. The increase in calcination temperature affects the Fe₂O₃ content, where the higher the temperature used, the lower the Fe₂O₃ content obtained. The Fe₂O₃ content in iron sand and after synthesis at temperatures of 600°C, 700°C, and 800°C were respectively 70.4%, 91.04%, 90.01%, and 88.82%
Studi Pemisahan Bijih Mangan dari Paludda Daerah Barru Menggunakan Shaking Table dengan Variasi Ukuran Butir: Separation Study of Manganese Ore from Palludda Barru Region Using Shaking Table with Variation of Grain Size Fraction Bakri, Suriyanto; Ratmi Nurhawaisyah, Sitti; Nurmalasari; Iksan, Muh.; Prayitna, Yusri; Putri, Syukrika
Journal of Engineering Science and Technology Applications Vol. 3 No. 1 (2025): Journal of Engineering Science and Technology Applications
Publisher : CV Insight Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58227/jesta.v3i1.217

Abstract

Manganese is one of the mineral products of mining, especially those found in Indonesia, such as in the Paludda area of Barru Regency, South Sulawesi. Manganese ore is known as raw material for steel industry, battery industry and chemical industry. This research was conducted at the Mining Engineering Study Program's Materials Processing Laboratory. The purpose of this study was to determine the percentage increase in manganese ore content after the concentration process, determining the recovery of manganese ore against variations in grain size using a shaking table. The analysis used in this research includes shaking table equipment, XRF analysis and also XRD analysis, from this processing will be obtained Mn content. The results of this study show shaking table separation using operating variables with an initial sample weight of 500 grams with levels in the initial sample of MnO of 33.58%, in concentrate -65 of 26.60%, concentrate -100 of 25.93%, concentrate -150 of 25.46%, concentrate -200 of 26.93%, in tailings -65 of 24.17%, tailings -100 of 23.79%, tailings -150 of 22.79% and tailings -200 of 22.60. Therefore, the results of the study can be concluded that the shaking table operation obtained the optimal concentrate and tailings in the -150 MnO concentrate with a recovery of 23.65%, then the -100 MnO tailings with a recovery of 38.68%
Sosialisasi Pengolahan Limbah Plastik Menjadi Bahan Bakar Minyak Bagi Siswa-Siswi UPT SMA Negeri 4 Parepare Nurmalasari, Nurmalasari; Putri, Syukrika; Bakri, Suriyanto; Prayitna, Yusri; Nisardi, Muhammad Rifki; Safitri, Dian; Rahmadani, Suci
Prima Abdika: Jurnal Pengabdian Masyarakat Vol. 5 No. 2 (2025): Volume 5 Nomor 2 Tahun 2025 (Juni)
Publisher : Program Studi Pendidikan Guru Sekolah Dasar Universitas Flores Ende

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37478/abdika.v5i2.5763

Abstract

The increasing problem of plastic waste poses a serious environmental challenge and requires environmentally friendly and educational solutions. This community service activity aims to introduce the design and implementation of a plastic waste processing device that converts plastic into fuel oil (BBM) using the pyrolysis method, targeting students at UPT SMA Negeri 4 Parepare. The program was implemented through counseling sessions, interactive discussions, and demonstrations of the pyrolysis device, adjusted to the students’ level of understanding. Evaluation was conducted using pre- and post-tests, participant satisfaction surveys, and direct observation. The results showed that 84% of students demonstrated improved understanding of the material, and participation and satisfaction rates exceeded 90%. These findings indicate that the activity not only succeeded in raising students’ environmental awareness but also provided them with practical knowledge about simple technology for plastic waste management.
ANALISIS SPASIAL KLOROFIL-A PERAIRAN PESISIR KOTA PAREPARE MENGGUNAKAN CITRA SENTINEL-2 Prayitna, Yusri; Ihsan, Muhammad
Nusantara Hasana Journal Vol. 5 No. 8 (2026): Nusantara Hasana Journal, January 2026
Publisher : Yayasan Nusantara Hasana Berdikari

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59003/nhj.v5i8.1873

Abstract

The coastal waters of Parepare City exhibited pronounced water quality dynamics during the 2024–2025 period, as reflected by fluctuations in the spatially averaged Normalized Difference Chlorophyll Index (NDCI) values ranging from −0.07 to 0.21. This study aims to analyze the spatial and temporal variability of chlorophyll-a in the coastal waters of Parepare using Sentinel-2 imagery and to evaluate the relationship between NDCI and bio-optical parameter estimates derived from the Case-2 Regional CoastColour (C2RCC) algorithm. The analysis was conducted using Google Earth Engine for NDCI computation and extreme-condition selection, accompanied by data quality filtering based on water-body masking and cloud screening. Two extreme conditions were identified, namely the HIGHEST condition on 14 January 2024 (mean NDCI = 0.2126) and the LOWEST condition on 28 May 2025 (mean NDCI = −0.0719), which were subsequently analyzed using the C2RCC algorithm applied to Sentinel-2 Level-1C imagery through the SNAP software. The results indicate that the coastal waters of Parepare exhibit typical Case-2 water characteristics, in which spatial variability in chlorophyll-a is generally associated with changes in Total Suspended Matter (TSM) driven by terrestrial material inputs. Although NDCI is effective as a relative indicator of chlorophyll-a variability, the occurrence of anomalies in littoral zones caused by mixed pixels highlights the necessity of integrating spectral indices with C2RCC based bio-optical estimates for robust monitoring of optically complex coastal waters.