scholarly journals KARAKTERISASI BATU KAPUR ALAM BUKIT JIMBARAN BALI

Jurnal Kimia ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 67
Author(s):  
Y. Ulfa ◽  
A.A. B. Putra ◽  
I N. Simpen

This research is about the characterization of naturar limestone in the Bukit Jimbaran area of Bali.  The aim of this research was to learn chemical composition and micromorphology of Bukit Jimbaran limestone. The research was conducted in sequential steps as described below i.e. the limestone was grinded and sieved in size of 0.25-0.50 mm. Fine limestone, then was heated by using oven at 1000 C for 24 hours and analyzed by FTIR, XRD and SEM. The Spectra of FTIR showed that O-H, C-H, and C-O were dominantly functional groups, which composed CaCO3 and CaO. The results of CaO crystal measurements using Scherrer equation is 51,39 nm. Micromorphology observation by using SEM showed size shaped (vaterite) of Bukit Jimbaran limestone

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Pepi Helza Yanti ◽  
Yendro Gandi

Hidroksiapatit (HAp) merupakan salah satu senyawa biokeramik yang digunakan dalam berbagai aplikasi.  Pada penelitian ini telah dilakukan sintesis hidroksiapatit (HAp) dengan metode pengendapan menggunakan cangkang lokan (Geloina coaxans) dan H3PO4  sebagai prekursor. Analisis menggunakan X-Ray Flourocence (XRF) menunjukkan bahwa komposisi kimia utama pada cangkang lokan (Geloina coaxans) adalah CaO.  Produk terbaik diperoleh melalui waktu kalsinasi pada suhu 900 oC selama 180 menit yang ditunjukkan dengan puncak yang memiliki intensitas tertinggi pada 2θ = 31,7o dan puncak spesifik lainnya untuk hidroksiapatit pada 2θ = 32,89o, 32, 17o, 25,86o dan 49,46o. Difraktogram dibandingkan dengan JCPDS (No 09-0432). Berdasarkan perhitungan menggunakan persamaan Scherrer, didapatkan ukuran kristal dari hidroksiapatit (HAp) adalah 26,62 nm. Analisis menggunakan FTIR juga telah dilakukan untuk mengidentifikasi gugus fungsi pada hidroksiapatit yang diperoleh. Dari spektrum FTIR menunjukkan adanya pita serapan yang khas untuk gugus  OH‒, CO32- dan PO43-pada hidroksiapatit. Morfologi partikel berbentuk granular seperti bola dan gumpalan yang tidak seragam diperoleh melalui analisis menggunakan SEM.. ABSTRACT  Hydroxyapatite (HAp) is a bioceramic compound that is used in various applications. In this research, hydroxyapatite (HAp) synthesis has been carried out by precipitation method using Geloina coaxans shell and H3PO4 as precursors. Analysis using X-Ray Flourocence (XRF) showed that the main chemical composition of Geloina coaxans shell was CaO. The best product was obtained by calcination at 900 oC for 180 minutes indicated by a peak having the highest intensity at 2θ = 31.7o and other specific peaks for hydroxyapatite at 2θ = 32.89o, 32 ,17o, 25.86o and 49.46o. The difractogram was compared to JCPDS (No 09-0432). Based on calculations using the Scherrer equation, the crystallite size of hydroxyapatite was 26.62 nm. Analysis using FTIR has also been carried out to identify the functional groups of the hydroxyapatite obtained. The FTIR spectrum showed that there were unique absorption bands  for OH‒, CO32- and PO43- groups on hydroxyapatite. Analysis using SEM showed that the morphology was granular like balls and non-uniform aggregate


2008 ◽  
Vol 59 (2) ◽  
pp. 212-215 ◽  
Author(s):  
Catalin Tanase ◽  
Aurel Pui

The present study is devoted to the IR�FT characterization of some fungi species, to the identification of their main functional groups, as well as to emphasize the presence of some toxic substances in the structure of certain sporiferous plants.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3255
Author(s):  
Lenka Kunčická ◽  
Michal Jambor ◽  
Adam Weiser ◽  
Jiří Dvořák

Cu–Zn–Pb brasses are popular materials, from which numerous industrially and commercially used components are fabricated. These alloys are typically subjected to multiple-step processing—involving casting, extrusion, hot forming, and machining—which can introduce various defects to the final product. The present study focuses on the detailed characterization of the structure of a brass fitting—i.e., a pre-shaped medical gas valve, produced by hot die forging—and attempts to assess the factors beyond local cracking occurring during processing. The analyses involved characterization of plastic flow via optical microscopy, and investigations of the phenomena in the vicinity of the crack, for which we used scanning and transmission electron microscopy. Numerical simulation was implemented not only to characterize the plastic flow more in detail, but primarily to investigate the probability of the occurrence of cracking based on the presence of stress. Last, but not least, microhardness in specific locations of the fitting were examined. The results reveal that the cracking occurring in the location with the highest probability of the occurrence of defects was most likely induced by differences in the chemical composition; the location the crack in which developed exhibited local changes not only in chemical composition—which manifested as the presence of brittle precipitates—but also in beta phase depletion. Moreover, as a result of the presence of oxidic precipitates and the hard and brittle alpha phase, the vicinity of the crack exhibited an increase in microhardness, which contributed to local brittleness.


2021 ◽  
Author(s):  
Ahmed Fouzi Tarchoun ◽  
Djalal Trache ◽  
Thomas M. Klapötke ◽  
Amir Abdelaziz ◽  
Mehdi Derradji ◽  
...  

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2597-2611 ◽  
Author(s):  
Mario Bandiera ◽  
Patrice Lehuédé ◽  
Marco Verità ◽  
Luis Alves ◽  
Isabelle Biron ◽  
...  

This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.


2017 ◽  
Vol 3 (1) ◽  
pp. 147-155 ◽  
Author(s):  
Haibo Wang ◽  
Chun Hu ◽  
Lang Yin ◽  
Sujia Zhang ◽  
Lizhong Liu

There is a relationship between biochemical function and chemical composition of corrosion scales, and Fe3O4formation reduced iron release.


Fuel ◽  
2017 ◽  
Vol 206 ◽  
pp. 555-563 ◽  
Author(s):  
Xueqiu He ◽  
Xianfeng Liu ◽  
Baisheng Nie ◽  
Dazhao Song

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