scholarly journals Effects of nanocrystalline calcium oxide particles on mechanical, thermal, and electrical properties of EPDM rubber

2021 ◽  
Author(s):  
Nashwan Q. Mahmood ◽  
Kálmán Marossy ◽  
Peter Baumli
Keyword(s):  
Calcium Oxide ◽  
Maximum Modulus ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Epdm Rubber ◽  
Roll Mill ◽  
Nanocrystalline Particles ◽  
Thermal And Electrical Properties ◽  
20 Nm ◽  
Twin Roll

AbstractIn this research, the effect of calcium oxide (CaO) nanocrystalline particles filled ethylene propylene diene monomer (EPDM) rubber composites is investigated, at different weight percentages (1.0, 2.0, 4.0, and 8 wt%) of CaO nanocrystalline particles using two methods of mixing. In one case conventional mixing on twin roll-mill was used, in the other case ultrasonic mixing as a pre-mixing was applied. CaO particles are synthesized by the precipitation method. The average crystallite size of CaO is 100 ± 20 nm. Adding CaO nanocrystalline particles increases the thermal stability of EPDM and the glass transition temperature. The hardness of EPDM rubber gradually increases with increasing the amount of CaO particles, the maximum hardness 64.2 observed in 8 wt% of CaO particles for both cases almost 26% higher than neat EPDM. Tensile strength decreases, while the maximum % modulus of the ultrasonic mixed sample was 1.48 MPa which is 24% higher than EPDM.

Synthesis and Characterization of Stabilized Tetragonal Nano Zirconia by Precipitation Method

2019 ◽  
Vol 56 ◽  
pp. 142-151
Author(s):  
Hassan Shokry ◽  
Marwa Elkady ◽  
Hesham Hamad
Keyword(s):  
Phase Transformation ◽  
Crystallite Size ◽  
Calcination Temperature ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Synthesis And Characterization ◽  
Calcination Temperatures ◽  
Ft Ir ◽  
20 Nm

Nano sized ZrO2 nanopowder was synthesized by precipitation method. Phase transformation was investigated as a function of calcination temperature by XRD, SEM , and FT-IR. It is indicated that the thermal anneling from 400 to 800 °C resulted in increasing the average crystallite size from 12 to 20 nm. As the calcination temperature increased, the crystallite size and the agglomeration were increased. The increase in the monoclinic content and grain growth are caused by the calcination temperatures even calcination at 800 °C.

Size-Dependence of Photoluminescence Property of ZnO Nanoparticles

2014 ◽  
Vol 887-888 ◽  
pp. 143-146 ◽  
Author(s):  
Xiao Fang Wang ◽  
Yun Liang Fang ◽  
Tian Le Li ◽  
Fu Juan Wang
Keyword(s):  
Grain Size ◽  
Lower Energy ◽  
Size Dependence ◽  
Surface States ◽  
Photoluminescence Property ◽  
Precipitation Method ◽  
Pl Spectra ◽  
Broadband Emission ◽  
Band Emission ◽  
20 Nm

Nanometer-sized ZnO crystals with the diameter from 20 nm to 110 nm were prepared by homogenous precipitation method (HPM). The photoluminescence (PL) spectra of as-prepared nanoparticles under excitation at the wavelength of 320 nm were detected. The PL spectra were fitted with Gaussian curves, in which a good fitting consisting of six Gaussian peaks was obtained. We observed that the multi-peak centers do not change much, while the relative amplitude of Gaussian combination to the band-to-band emission decreases rapidly with the increased grain size. It shows that the broadband emission at the lower energy is associated with the surface states.

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 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%.

Effect of the ratio ZnO: ZrO2 on the photocatalytic ability of phenol degradation in ZnO-ZrO2 nanocompsite materials

2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Thao Pham Thi Minh ◽  
Huong Do Thi ◽  
Hai Le Thi
Keyword(s):  
Photocatalytic Activity ◽  
Crystallite Size ◽  
Phenol Degradation ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Ultrasonic Vibrations ◽  
Phenol Content ◽  
Photocatalytic Ability ◽  
Photocatalytic Reactions

The ZnO-ZrO2 nanocompsite materials in the molar ratio (1:0; 1:1; 1:2; 2:1; 3:4; 4:3; 0:1) were prepared by a two-stage precipitation method with ultrasonic vibrations. The obtained ZnO-ZrO2 materials were characterized by XRD, SEM, UV-vis. XRD data identified phase of the ZnO and phase of ZrO2 in all obtained samples. The average crystallite size of the samples was between 18 to 30 nm. As UV-Vis spectra, the band gap of ZnO-ZrO2 composite (ZZ34R) is 3,06eV. The photocatalytic reactions confirmed that the nanocomposite sample showed higher photocatalytic activity than the pure oxides samples for the degradation phenol under 100W incandescent lamp. Among the prepared samples, the best sample for photocatalytic degration of phenol is the ZZ34R which the molar ratio ZnO:ZrO2 = 3:4 with 23% remaining phenol content after 300 minutes. The photodegradation phenol of sample with ultrasonic vibrations is higher than the sample without ultrasonic vibrations. This indicates that the materials are capable of treating phenol in wastewater.

scholarly journals Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Carmen Steluta Ciobanu ◽  
Simona Liliana Iconaru ◽  
Florian Massuyeau ◽  
Liliana Violeta Constantin ◽  
Adrian Costescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Textural Properties ◽  
Average Crystallite Size ◽  
Luminescent Properties ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vibrational Studies ◽  
20 Nm

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO4)6(OH)2) with0≤x≤0.2nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic5D0→7F0transition observed at 578 nm related to Eu3+ions distributed on Ca2+sites of the apatitic structure.

XRD and Photoluminescence Properties of CaSO4:Dy Phosphor Synthesized by New Co-Precipitation Method

2017 ◽  
Vol 888 ◽  
pp. 333-337 ◽  
Author(s):  
Nadira Kamarudin ◽  
Wan Saffiey Wan Abdullah ◽  
Muhammad Azmi Abdul Hamid
Keyword(s):  
Calcium Sulfate ◽  
Average Crystallite Size ◽  
Information Storage ◽  
Precipitation Method ◽  
Photoluminescence Properties ◽  
Orthorhombic Crystal ◽  
Phosphor Material ◽  
X Ray ◽  
Wide Range ◽  
Co Precipitation

This paper presents the luminescence properties of dysprosium (Dy) doped calcium sulfate (CaSO4) phosphor material produced by co-precipitation technique with 0.1 - 0.5 mol% concentration of dopant. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectrum shows high purity anhydrite CaSO4 phosphor material produced. The average crystallite size of 74 nm with orthorhombic crystal system was obtained. The luminescence behavior of produced CaSO4: Dy was studied using a photoluminescence (PL) spectrometer. The excitation and emission spectrum peaks associated with defects and vacancies of the phosphor material at claimed crystalline phase. The mixed peaks of excitation and emission that corresponds to micro and nano sized particle was shown for the produced powders. These properties show that the produced powders have wide range of luminescence detection with many electron traps ready for thermoluminescence (TL) information storage.

Effect of hybrid-SiO2 particles on characterization of EPDM and silicone rubber composites for outdoor high-voltage insulations

2017 ◽  
Vol 37 (7) ◽  
pp. 671-680 ◽  
Author(s):  
Hidayatullah Khan ◽  
Muhammad Amin ◽  
Muhammad Yasin ◽  
Muhammad Ali ◽  
Ayaz Ahmad
Keyword(s):  
High Voltage ◽  
Silicone Rubber ◽  
Hybrid Composites ◽  
Standard Procedure ◽  
Research Work ◽  
Dielectric Strength ◽  
Hybrid Silica ◽  
Roll Mill ◽  
Thermal And Electrical Properties

Abstract Ethylene propylene diene monomer (EPDM) and silicone rubber (SiR) are well-known polymers for high-voltage (HV) outdoor applications. In this research work, the effect of hybrid SiO2 (a mixture of 15% microsized and 5% nanosized silica) has been investigated on the mechanical, thermal, and electrical properties of EPDM and SiR composites. Using the ASTM standard procedure, the EPDM and SiR composites filled with hybrid silica were compounded by two roll mill and simple blending techniques, respectively. It was observed that with the addition of hybrid SiO2, the composites exhibited improved tensile strength of ~2500 kPa, reduced elongation at break, and enhanced hardness. The samples filled with SiR hybrid silica showed higher thermal stability and volume/surface resistivities relative to EPDM hybrid composites. However, EPDM hybrid composites showed higher dielectric strength of ~23.4 kV/mm as compared with SiR composites. From these characterization results, it can be suggested that SiR hybrid composites are more suitable for outdoor HV insulation applications.

BLUE EMISSION AND BANDGAP MODIFICATION IN N:ZnO NANORODS

2011 ◽  
Vol 04 (03) ◽  
pp. 271-275 ◽  
Author(s):  
N. RAJESWARI YOGAMALAR ◽  
M. ASHOK ◽  
A. CHANDRA BOSE
Keyword(s):  
Electron Microscopy ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Average Crystallite Size ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Tauc Plot ◽  
Transmission Electron ◽  
N Doping ◽  
Ir Study

Nanorods of nitrogen-doped ZnO (N:ZnO) are grown by hydrothermal chemical precipitation method. The average crystallite size, surface morphology, and particle size distribution are estimated and characterized from powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The characteristic vibration mode of metal-oxide is confirmed from Fourier transform infrared spectroscopy (FT-IR) study. The absorption spectra of N:ZnO in the ultraviolet visible (UV-vis) region and their variations are recorded as a function of dopant concentration. The Tauc plot elucidates that the bandgap of N:ZnO increases up to 6 atomic percent (at.%) of dopant concentration and then decreases for heavy doping. The widening and narrowing in bandgap is interpreted in terms of impurity induced absorption edge shift due to N doping. Photoluminescence (PL) spectra revealed the existence of visible band, arising from impurity related defects.

scholarly journals Calcium pyrophosphate powder derived from avian eggshell waste

Cerâmica ◽  
2016 ◽  
Vol 62 (363) ◽  
pp. 278-280 ◽  
Author(s):  
T. H. A. Corrêa ◽  
J. N. F. Holanda
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
Average Crystallite Size ◽  
Calcium Pyrophosphate ◽  
Precipitation Method ◽  
Medical Applications ◽  
X Ray Diffraction ◽  
X Ray ◽  
Eggshell Waste ◽  
Scanning Electron

Abstract Calcium pyrophosphate (CPP) was prepared by a simple precipitation method using avian eggshell waste as a low-cost alternative calcium precursor source. The synthesized CPP powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The results indicate that pure β-CPP nanocrystallites (Ca/P = 1.067) were successfully synthesized from avian eggshell waste. The correlation among XRD, SEM/EDS, TGA, and FTIR data is well established. The β-CPP particle exhibited spherical morphology with average crystallite size of 62.3 nm, and can be an important bioceramic for medical applications.

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