scholarly journals PENGARUH FLOURIDE TERHADAP SIFAT MEKANIK GIGI TIRUAN BERBAHAN DASAR LIMBAH CANGKANG TELUR AYAM

2019 ◽  
Vol 4 (1) ◽  
pp. 72-77
Author(s):  
Baiq R. S. Yusuf ◽  
Siti Alaa ◽  
Dian W. Kurniawidi ◽  
Susi Rahayu
Keyword(s):  
Functional Groups ◽  
Calcium Oxide ◽  
Mechanical Tests ◽  
Precipitation Method ◽  
Oxide Content ◽  
Distilled Water ◽  
Minimum Standard ◽  
Fluoride Toothpaste ◽  
Egg Shells

The fabrication of dentures from the eggshell has been done using the precipitation method. FTIR and AAS tests were carried out to determine the functional groups and calcium oxide content in egg shells. From the AAS results, the CaO value is 58.33% which is much greater than the minimum standard CaO in dentures. Mechanical tests were carried out on dentures treatment with immersion into distilled water and the results were compared if immersion using fluoride toothpaste. It was found that immersion with fluoride toothpaste can increase the elasticity of dentures by more than 100%.

scholarly journals Reusability and Stability Tests of Calcium Oxide Based Catalyst (K2O/CaO-ZnO) for Transesterification of Soybean Oil to Biodiesel

2016 ◽  
Vol 11 (1) ◽  
pp. 34 ◽  
Author(s):  
Istadi Istadi ◽  
Udin Mabruro ◽  
Bintang Ayu Kalimantini ◽  
Luqman Buchori ◽  
Didi Dwi Anggoro
Keyword(s):  
Catalytic Activity ◽  
Soybean Oil ◽  
Calcium Oxide ◽  
Acid Methyl Ester ◽  
Potassium Nitrate ◽  
Operating Conditions ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
High Catalytic Activity ◽  
Stability Tests

<p>This paper was purposed for testing reusability and stability of calcium oxide-based catalyst (K<sub>2</sub>O/CaO-ZnO) over transesterification reaction of soybean oil with methanol to produce biodiesel. The K<sub>2</sub>O/CaO-ZnO catalyst was synthesized by co-precipitation method of calcium and zinc nitrates followed by impregnation of potassium nitrate. The fresh and used catalysts were tested after regeneration. The catalysts were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and BET Surface Area in order to compare the catalyst structure between the fresh and used catalysts. The catalyst testing in transesterification proses was carried out at following operating conditions, i.e. catalyst weight of 6 wt.%, oil to methanol mole ratio of 1:15, and temperature of 60 oC. In addition, metal oxide leaching of K<sub>2</sub>O/CaO-ZnO catalyst during reaction was also tested. From the results, the catalysts exhibited high catalytic activity (80% fatty acid methyl ester (FAME) yield after three-cycles of usage) and acceptable reusability after regeneration. The catalyst also showed acceptable stability of catalytic activity, even after three-cycles of usage. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 10<sup>th</sup> November 2015; Revised: 16<sup>th</sup> January 2016; Accepted: 16<sup>th</sup> January 2016</em></p><p><strong>How to Cite</strong>: Istadi, I., Mabruro, U., Kalimantini, B.A.,  Buchori, L., Anggoro, D.D. (2016). Reusability and Stability Tests of Calcium Oxide Based Catalyst (K<sub>2</sub>O/CaO-ZnO) for Transesterification of Soybean Oil to Biodiesel. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (1): 34-39. (doi:10.9767/bcrec.11.1.413.34-39)</p><p><strong>Permalink/DOI</strong>: <a href="http://dx.doi.org/10.9767/bcrec.11.1.413.34-39">http://dx.doi.org/10.9767/bcrec.11.1.413.34-39</a></p><p> </p>

scholarly journals Iron oxide/titania composites for radar absorbing material (RAM) applications

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 470-476 ◽  
Author(s):  
A. Fisli ◽  
D. S. Winatapura ◽  
E. Sukirman ◽  
S. Mustofa ◽  
W. A. Adi ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Pore Volume ◽  
Weight Ratio ◽  
Total Pore Volume ◽  
Precipitation Method ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
Radar Absorbing Material ◽  
Radar Signature ◽  
Absorbing Material

Abstract Iron oxide/titania composites were synthesized by precipitation method. Amount of iron oxide was varied in the composites. The single phase (anatase) was obtained for the weight ratio of 0-20% and three phases (anatase, magnetite and hematite) were found for the weight ratio of 30% and 40% of iron oxide. The crystallite size of titania decreased with increasing of iron oxide content. The specific surface area, total pore volume and BJH pore volume of the sample increased with increasing iron oxide content in the composite. The composites possessed mesoporous characteristic (6.5-9.6 nm in pore diameter) and exhibited ferromagnetic properties. The measurement of the microwave absorption showed that the 40Fe/Ti composite had the best reflection loss of -14 dB at a frequency of 10.9 GHz. This meant that the electromagnetic wave was absorbed 80% in that frequency. Thus, the developed material can be a promising microwave absorbing agent in radar signature reduction.

Effect of CaSO4 Dissolution-Precipitation Time on Formation of Porous Carbonate Apatite as Bone Replacement Material

2020 ◽  
Vol 44 ◽  
pp. 83-90 ◽  
Author(s):  
Kusuma Eriwati Yosi ◽  
Arsista Dede ◽  
Triaminingsih Siti ◽  
Sunarso
Keyword(s):  
Functional Groups ◽  
Calcium Sulfate ◽  
Precipitation Method ◽  
Regeneration Ability ◽  
Carbonate Apatite ◽  
Type B ◽  
X Ray Diffraction ◽  
Bone Replacement Material ◽  
Bone Replacement ◽  
Thermo Fisher Scientific

Introduction: Carbonate apatite type B (C-Ap) has been used as a bone replacement material because of its osteoconductive properties. Clinically, the pores formed in bone replacement material aid in cell mobility and nutrient supply, thereby increasing the bone regeneration ability. CO32- ions found in this material are useful for maintaining a stable physiological environment in the bone in order for it to be easily absorbed by osteoclasts. Porous C-Ap type B is formed using the dissolution–precipitation method by immersing porous anhydrous CaSO4 in a mixture of carbonate and phosphate solutions. Purpose: The present study aimed to evaluate the effect of immersion ofCaSO4using the dissolution–precipitation method on the formation of porous C-Ap type B with calcium sulfate precursor hemihydrate. Method: Porous C-Ap type B was produced usinga mixture of calcium sulfate hemihydrate precursors with 50 wt% polymethylmethacrylate (PMMA) porogen and distilled water. After hardening, the calcium sulfate dihydrate containing PMMA was burned in an oven at 700°C for 4 h to remove the PMMA. The specimen was immersed in a mixture of sodium phosphate (Na3PO4) and sodium carbonate (Na2CO3) for 6, 12, and 24 h. Phase testing through X-ray diffraction (XRD) using CuKα radiation at 40 kV and 40 mA was performed. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR, Thermo Fisher Scientific, Waltham, Massachusetts, USA) was used for detecting the functional groups of CO32- and PO42-. Results: XRD results showed the formation of C-Ap at 6 and 12 h, but the anhydrous CaSO4 phase remained; alternatively, this phase was absent after 24 h of immersion phase andFTIR showed the presence of the functional groups of CO32- compounds. Conclusion: Porous C-Ap type B can be formed from CaSO4 precursors after 24 h of immersion using the dissolution–precipitation method.

Particle Loosening on the Surface of Dense Hydroxyapatite in Water

2012 ◽  
Vol 217-219 ◽  
pp. 983-987
Author(s):  
Dong Seok Seo ◽  
Hong Hwang Kyu ◽  
Jong Kook Lee
Keyword(s):  
Stoichiometric Composition ◽  
Cold Isostatic Pressing ◽  
Precipitation Method ◽  
Distilled Water ◽  
Initial Value ◽  
Liquid Environment ◽  
Dense Microstructure ◽  
Phase Pure ◽  
Second Phases ◽  
Extended Exposure

This work describes dissolution and related mechanical weakening of phase-pure and dense hydroxyapatite (HA) in distilled water of pH 7.4. Phase-pure HA powder has been synthesized by a wet precipitation method. After uniaxial and cold isostatic pressing, and sintering at 1200°C, dense HA with 98% above of the theoretical density has been obtained. The results show that HA powder has stoichiometric composition with a Ca/P ratio 1.67 ± 0.02. Even after extended exposure for 10 h, no second phases, such as tricalcium phosphate (TCP) and calcium oxide can be observed. Although the HA is supposed to be stable in liquid environment, surface dissolution appears specifically at material’s grain boundaries after immersion for 7 days. Following further immersion to 14 days, grain boundary dissolution progresses interior to the bulk following these paths. This dissolving behavior generates HA particles, disintegrates dense microstructure and at least forms micron-scale cavity. Mechanical property of the HA has been also affected. Fracture toughness (KIc) of the HA sintered body is approximately 1.0 MPa•m1/2. It drastically decreases to almost half of the initial value due to the severe surface dissolution

scholarly journals Spectroscopic Analysis of Heterogeneous Biocatalysts for Biodiesel Production from Expired Sunflower Cooking Oil

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Enoch Wembabazi ◽  
Patrick Joram Mugisha ◽  
Asumani Ratibu ◽  
Deborah Wendiro ◽  
Joseph Kyambadde ◽  
...  
Keyword(s):  
Calcium Oxide ◽  
Sunflower Oil ◽  
Active Form ◽  
Single Step ◽  
Biodiesel Production ◽  
Saw Dust ◽  
Heterogeneous Biocatalysts ◽  
Egg Shells ◽  
Heterogeneous Biocatalyst

The study characterized heterogeneous biocatalyst synthesized from sucrose, saw dust, and chicken egg shells using Fourier Transform Infrared (FTIR) spectroscopy coupled with Attenuated Total Reflectance (ATR) technique. Acidic sulphonate (–SO3H) groups were more visible in the spectrum generated for carbonized and sulphonated sucrose than in carbonized and sulphonated saw dust. This was highlighted further by the significantly higher conversion percentage achieved for sulphonated sucrose (62.5%) than sulphonated saw dust (46.6%) during esterification of expired sunflower oil (p=0.05). The spectra for calcinated egg shells also showed that the most active form of calcium oxide was produced at calcination temperature of 1000°C. This was confirmed in the single-step transesterification reaction in which calcium oxide generated at 1000°C yielded the highest biodiesel (87.8%) from expired sunflower oil. The study further demonstrated the versatility of the FTIR technique in qualitative analysis of biodiesel and regular diesel by confirming the presence of specific characteristic peaks of diagnostic importance. These findings therefore highlight the potential of FTIR-ATR as an inexpensive, fast, and accurate diagnostic means for easy identification and characterization of different materials and products.

The Use of FBC Fly Ash in the Preparation of Portland Cement Clinker

2016 ◽  
Vol 722 ◽  
pp. 168-172
Author(s):  
Karel Kulísek ◽  
Dominik Gazdič ◽  
Karel Dvořák ◽  
Marcela Fridrichová
Keyword(s):  
Fly Ash ◽  
Calcium Oxide ◽  
Calcium Silicate ◽  
Raw Material ◽  
Cement Clinker ◽  
Oxide Content ◽  
Fly Ashes ◽  
Portland Cement Clinker ◽  
The Impact ◽  
Fbc Fly Ash

The present work focuses on the use of fluid fly ash for Portland clinker burning. Fluid ashes are carriers of all basic oxides represented in the cement raw meal. However, while the share of hydraulic oxides is in ashes sufficient, there is a significant deficiency in calcium oxide content. Preliminary studies have shown that the combination thereof with calcite as the second essential component of the fluid fly-ashes for the raw material based on Portland clinker burning application, it is necessary to solve a problematic issues. The first one concerns the potential leakage SOx resulting from decomposition of CaSO4 ash into the atmosphere. The second circumstance is the correction tracks raw meal in order to redistribute in the samples prepared under the initial studies, the obtained clinker minerals content in favor of calcium silicate, of them further in favor of alite. The last issue is the evaluation of the impact of fluid utilization of fly ash as a partial raw material bases for reducing CO2 emissions in the Portland clinker burning.

scholarly journals Characteristic of Cowpea (Vigna unguiculata) Protein Concentrates Protein Fraction on their Solubility

2020 ◽  
Vol 13 (1) ◽  
pp. 30-37
Author(s):  
Ika Ratna Agustin ◽  
Yunianta ◽  
Teti Estiasih
Keyword(s):  
Functional Properties ◽  
Vigna Unguiculata ◽  
Food Product ◽  
Precipitation Method ◽  
Distilled Water ◽  
Maximum Solubility ◽  
Protein Concentrates ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
High Concentrations

Cowpea (Vigna unguiculata L. Walp) has a protein content of 22,9% to obtain the protein in high concentrations, is made as a concentrates or isolates protein. The aim of study to determine of chemical and functional properties of flour and cowpea protein concentrates on their solubility. The study uses a completely randomized design with precipitation method based on solvent, there is distilled water, 5% salt solution, alkaline solution (NaOH 0,5 N) and ethanol 70%. The result showed that cowpea protein fractions of albumin, globulin, glutelin and prolamin had different minimum and maximum solubility. Flour and cowpea protein concentrates had different chemical composition and functional properties. Flour and cowpea protein concentrates can be develop in various food product

scholarly journals PENGARUH WAKTU KALSINASI TERHADAP SIFAT FISIKA-KIMIA HIDROKSIAPATIT DARI CANGKANG GELOINA COAXANS

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Pepi Helza Yanti ◽  
Yendro Gandi
Keyword(s):  
Chemical Composition ◽  
Crystallite Size ◽  
Functional Groups ◽  
Ftir Spectrum ◽  
Precipitation Method ◽  
Absorption Bands ◽  
X Ray ◽  
Main Chemical Composition ◽  
Scherrer Equation

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

scholarly journals EKSTRAKSI KALIUM DARI KULIT BUAH KAPUK (Ceiba petandra)

2018 ◽  
Vol 7 (2) ◽  
pp. 17-22
Author(s):  
Chandra Sitorus ◽  
Lilis Sukeksi ◽  
Andy Junianto Sidabutar
Keyword(s):  
Atomic Absorption ◽  
Atomic Absorption Spectroscopy ◽  
Ash Content ◽  
Potassium Oxide ◽  
Oxide Content ◽  
Distilled Water ◽  
Combustion Time ◽  
Muffle Furnace ◽  
Fruit Peel ◽  
Time Variables

The purpose of this study was to determine the best  of combustion time and temperature of ash production from kapok fruit peel ( Ceiba Petandra ) to get the most potassium. The experiment was begun to dry kapok  fruit peel for 24 hours at oven with temperature 110 oC and combustion to obtaine the ash from kapok fruit peel. The combustion was done by muffle furnace which time variables were from  3 hours, 4 hours, 5 hours, and 6 hours and burning temperature variables were from, 500 oC, 550 oC,600 oC, 650oC. The potassium that contained in ash have been extracted by distilled water with volume 30 ml  for 24 hours. Observed responses were normality, pH, ash content,  and potassium oxide content (% K2O). The best result of ash was in 3 hours with temperature 500 oC. The ash was analyzed by using AAS Atomic Absorption Spectroscopy, and 35.91 % of potassium oxide (K2O) content was obtained as maximum result.

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