Hidroksiapatit (HAp) merupakan senyawa mineral apatit. HAp merupakan senyawa yang memiliki kemiripan dengan bagian mineral dalam tulang. Pemanfaatan hidroksiapatit dalam bidang medis khususnya dalam bidang kedokteran gigi terus dikembangkan dalam berbagai penelitian, salah satu contohnya adalah pemanfaatan hidroksiapatit dari cangkang kerang darah sebagai semen tambal gigi. Tujuan penelitian ini adalah mengetahui struktur kristal, ukuran butiran dan sifat mekanik hidroksiapatit dari cangkang kerang darah. Metode yang digunakan dalam penelitian ini adalah metode eksperimen dengan menggunakan alat uji XRD untuk mengetahui struktur dan ukuran butiran krital sedangkan alat Universal Testing Mechine (UTM) digunakan untuk mengetahui kuat tekan sampel. Hasil penelitian menunjukkan struktur kristal yang dihasilkan dari sintesis hidroksiapatit cangkang kerang darah adalah aragonite dengan rata-rata ukuran kristal yang dihasilkan sebesar 5,87 nm. Sedangkan nilai kuat tekan yang terbesar diperoleh pada sampel 2 yaitu 9,521 MPa, sedangkan nilai kuat tekan yang terkecil yaitu pada sampel 1 sebesar 3,51 MPa.
The study of soil minerals structure has been conducted in the Sawaru village, Maros regency, South Sulawesi which is locally known to be the landslides-prone area. The aim of this research is basically to determine the mineral characteristics of the soil. The samples were taken randomly in three points with a depth of 75 cm at point 1 and 100 cm for the other. The structure of the samples was analyzed using X-Ray Diffraction (XRD) where the samples were placed in the high temperature and airtight containers. The results of XRD analysis showed that minerals contained at point 1 (75 cm in depth) were illite (69.3%) with a monoclinic structure, albit mineral (25.6%) with a triclinic structure and kaolinite (5.0%) with a triclinic structure. Samples at point II (100 cm depth) contained illite (67.2%), feldspar (23.9%) with monoclinic and merrillit (8.9%) with trigonal structures. Samples at point III (100 cm in depth) contained illite (55.9%), bobtraillite (22.2%) with a trigonal structure and feldspar (21.9%) with a monoclinic structure. The minerals observed at the sampling points are dominated by illite which is clay in nature. Such a mineral has been known to have an ability to initiate high plasticity in soil, leading to the slope instability.
This study aims to identify the direction and type of active faults in the region of South Sulawesi by using the hypocenter and Centroid (HC). The data used is secondary data obtained from the hypocenter USGS, IRIS, GEOFON website and the data obtained from BMKG centroid that is processed using the focus mechanism to coordinate limit −3°− 6° 30′ LS-119°− 120° BT.
This study aims to determine how much electrical energy or power density produced from the sago stem substrate using Microbial Fuel Cell (MFC) technology without the addition of electrolytes by adding KMnO4 and K3Fe (CN) 6 as an electrolyte solution. From the measurement results, it is obtained that the sago stem substrate sample has electrical potential or power density (mW/m2). The large power density (mW/m2) produced from the sago stem substrate using lactobacillus plantarum bacteria without the addition of an electrolyte solution was obtained at 50,082 mW/m2. For samples with the addition of 0.2 M KMnO4 and potassium phosphate buffer with pH 7, a power density value of 91,082 mW/m2 was obtained and the addition of K3Fe (CN) 6 0.2 M and sodium phosphate buffer with pH 7 obtained a power density value of 27,287 mW/m2.
The research on corrosion rate analysis of concrete iron with swamp soil medium has been conducted. The aims of this study were to determine the corrosion rate and the types of corrosion that occurred in concrete iron with swamp soil medium. The methods of this study are Weight Loss method, Atomic Absorption Spectroscopy (AAS) test, and Scanning Electron Microscope-Energy Dispersion X-Ray (SEM-EDX). This study used a different immersion time variant, such as 20 days, 40 days, 65 days, and without medium for 65 days. The concrete iron used in this study is concrete U-24 or plain concrete iron 10. The corrosion rate that occurs in iron concrete with swamp soil medium at 20 days immersion is 20977.5868 mmpy, 40 days immersion is 17721.9174 mmpy, 65 days immersion is 16932. 9071 and 65 days without a medium are 3023.3793 mmpy. The more time, the rate of corrosion become more slowly due to the influence of corrosion products that have occurred. The corrosion rate without the medium is slower than the corrosion rate with the medium. The types of corrosion that occurs in concrete iron with swamp soil medium are crevice corrosion and pitting corrosion.
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