Carbonated calcium hydroxyapatite (CHAp) exhibits excellent biocompatibility with bone and teeth, making it an ideal candidate for orthopedic and dental application. However, the study of CHAp synthesis from natural material is still scarce. The purpose of this research is to synthesize and characterize of CHAp, using Rebon shrimp (Acetes erythraeus) as a calcium source. The synthesis was conducted by hydrothermal method with the variation of Ca/P ratios 1.61; 1.67; 1.73. The as-prepared CHAp was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray (SEM-EDX). The FT-IR results show that synthesized material exhibited characteristic CHAp band of hydroxide at 3448 and 1635 cm-1, carbonate at 872 and 1427 cm-1, and phosphate at 1049; 606; and 570 cm-1. The diffractogram pattern assigned the all observed peak of CHAp are in good agreement compared to CHAp database with the nano-scale size. It also observed that the high Ca/P ratio will decrease the crystallinity of CHAp. The as-prepared CHAp micrograph is agglomerates spherical form with size between 5-20 nm which build up from 18–26 nm crystallite particles. The result of this research confirmed that Rebon shrimp is the promising materials for calcium source in CHAp production.

ABSTRAK

[Analysis Of Silicone (Si) in Coal of PT. Tambang Bukit Tambi Jambi Province]Batubara merupakan komoditas hasil tambang dan merupakan produk andalan di Provinsi Jambi. Batubara merupakan endapan sedimen yang terdiri dari komponen organik dan anorganik, yang mengandung jenis-jenis mineral yang terikat didalamnya, yaitu diantaranya C, Si dan Al. Tujuan penelitian ini adalah melakukan analisis kandungan silikon untuk menentukan jenis batubara yang dihasilkan oleh PT. Tambang Bukit Tambi. Metode yang dilakukan adalah dengan mengekstraksi batubara menggunakan NaOH 3M dan HCl 1 M dan dilanjutkan engan metode metalotermis. Hasil ekstraksi diperoleh silika adalah massa rata-rata sebesar 4,89 gram dengan persentasi kadar 46,57%. Kadar silikon yang didapatkan dari hasil metalotermis yang dianalisis menggunakan AAS adalah sebesar 7,23%. Berdasarkan kadar silikon, maka batubara PT. Tambang Bukit Tambi dikategorikan dalam jenis batubara sub bituminus.

<p>The roasting process has brought about some changes in transition phases, in chemical characteristics, and microstructures of minerals in the Liberica coffee beans. Two initial roasting temperature variations were carried out to study the thermal behavior and characteristic of Liberica coffee, namely 200 °C and 230 °C. The thermal behaviour of phase changes of the Liberica green and ground coffee after the roasting process has been identified by using Differential Scanning Calorimeter (DSC). Chemical functional groups and molecular structures have been well-analyzed by using Fourier-Transform Infrared Spectroscopy (FTIR), Liquid Chromatography-Mass Spectrometry (LC-MS), Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy (SEM/EDX) and X-Ray Powder Diffractions (XRD) for the green and roasted Liberica coffee. The DSC spectra indicated a high decomposition process that occurred during thermal treatment with crystallization and melting temperature around 120 °C and 325 °C for both roasting initial temperature variations, respectively. The FTIR and LC-MS are able to identify the chemical change in both the green and the roasted coffee. The dominant compounds found in the roasted Liberica coffee are caffeine, trigonelline, nicotinic acid, and dehydrocafestol. The XRD spectrum indicates that there is an amorphous phase for the green coffee and a sucrose crystal phase for the roasted coffee within the activity in 2θ = 20.3° and 21.1°.</p>

Ecoprint is a technique for printing colors and shapes on fabric using natural materials. Ecoprint techniques have been introduced to junior high school students because they can capture the material and teacher's instructions independently, think critically and creatively. The purpose of the ecoprint introduction activity is to provide knowledge about ecoprint and students' skills in utilizing local potential through natural materials or plants around the school. The methods used are lectures, demonstrations, practice, and evaluation. The questionnaires and direct observations on ecoprint products were used as evaluations for this activity. Students have been able to print motifs and colors from leaves and flowers on a cloth to produce ecoprint products according to their respective creativity.