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Structural, Optical and Magnetic Properties of (Ni, Al) Co-Doped ZnO Nanoparticles
Peyyala Swapna,
Sakirevupalli Venkatramana Reddy
Issue:
Volume 8, Issue 1, March 2019
Pages:
1-11
Received:
26 December 2018
Accepted:
21 January 2019
Published:
13 February 2019
Abstract: We synthesize pure and (Ni, Al) co-doped Zinc Oxide (ZnO) nanoparticles by chemical co-precipitation method at room temperature successfully using poly ethylene glycol (PEG) as stabilizing agent. In the preparation, we kept one dopant element aluminum at constant concentration, 5 mol% by varying the other dopant concentration from one to three mol%. Following the completion of synthesis, the nanopowders are cautiously subjected to diverse characterizations such as XRD, SEM with EDS, TEM, PL, UV-Vis-NIR, Raman and VSM to determine the properties to be found the structural, optical and magnetic. XRD data shows that all the nanopowder samples acquire hexagonal wurtzite crystal structure by means of no secondary phases connecting to aluminum or nickel; this indicates the well dissolution of aluminum and nickel in to ZnO host lattice. The exact size of particles is predicted using TEM illustrations, which are more or less confirmed by the XRD data. The morphology of the samples is identified using SEM images, and EDS spectrum reveals that no impurities are present in the powder samples than nickel and aluminum. Optical properties are deliberated via PL spectrum and UV-Vis-NIR spectra, every one of the samples have defect related peaks in the visible region. Magnetic properties are estimated by means of the technique VSM, except pure ZnO nanoparticles remaining all the doped samples contains the Ferro magnetic nature.
Abstract: We synthesize pure and (Ni, Al) co-doped Zinc Oxide (ZnO) nanoparticles by chemical co-precipitation method at room temperature successfully using poly ethylene glycol (PEG) as stabilizing agent. In the preparation, we kept one dopant element aluminum at constant concentration, 5 mol% by varying the other dopant concentration from one to three mol%...
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Recovery of Valuable Metals from Spent Lithium Ion Batteries (LIBs) Using Physical Pretreatment and a Hydrometallurgy Process
Kai-Lun Chiu,
Yun-Hwei Shen,
Yi-Hsuan Chen,
Kaun-Yu Shih
Issue:
Volume 8, Issue 1, March 2019
Pages:
12-20
Received:
28 December 2018
Accepted:
20 January 2019
Published:
21 February 2019
Abstract: Lithium ion batteries are the most commonly used batteries at present, and because of the large number of people using and manufacturing them, the serious environmental problems caused by the final disposal of waste lithium batteries are worth discussing. In this study, lithium ion batteries were crushed with a crusher, and the obtained powder was then sieved and collected. The valuable metals in the lithium ion batteries were recovered using a hydrometallurgy process. The research included the use of acid leaching and chemical precipitation. Acid leaching of the cathode electrode powder with three kinds of acids, including citric acid, sulfuric acid, and hydrochloric acid, resulted in a leaching solution rich in lithium, cobalt, nickel, and manganese. The leaching solution obtained from hydrochloric acid leaching was selected as the liquid to be used for the precipitation experiments. Precipitation was performed first using a selective chemical precipitation method, and manganese was first precipitated as a black powder. The color of the leaching solution after manganese precipitation changed to dark pink, and the liquid was full of cobalt and nickel. Then, the cobalt and nickel were co-precipitated with ammonium citric, and the obtained precipitates were either pale pink or grayish pink. After precipitation of cobalt and nickel, only lithium was left in the transparent, colorless leaching liquid. Finally, lithium was concentrated through reduced pressure evaporation, and a green lithium salt was obtained.
Abstract: Lithium ion batteries are the most commonly used batteries at present, and because of the large number of people using and manufacturing them, the serious environmental problems caused by the final disposal of waste lithium batteries are worth discussing. In this study, lithium ion batteries were crushed with a crusher, and the obtained powder was ...
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Effect of Diamond-Like Carbon Thin Film on the Fatigue Strength of AISI 4340 Steel
Tjipto Sujitno,
Emy Mulyani,
Suprapto,
Wiwien Andriyanti,
Didy Suharlan,
Viktor Malau
Issue:
Volume 8, Issue 1, March 2019
Pages:
21-26
Received:
15 January 2019
Accepted:
20 February 2019
Published:
12 March 2019
Abstract: AISI 4340 is known as super strength steel and widely applied in military equipment, aircraft components, automotive components, drilling device and so on because of its excellent behavior in wear, corrosion, fatigue, high temperature, and high-speed operating conditions. However, due to continuing work which reduced the performance of that component surface during their service life, an effort to improve the surface properties for a longer service life should be carried out. This paper presents the research result of the influence of diamond-like carbon coating deposited using home-made DC Chemical Vapor Deposition (DC-CVD) on the surface of AISI 4340 steel. As a carbon source, a mixture of argon (Ar) and methane (CH4) with a ratio of 24%: 76% was used in this experiment. The conditions of the experiment were 400°C of temperature at various gas pressures (1.2 mbar, 1.4 mbar, 1.6 mbar, 1.8 mbar, and 2.0 mbar) for 5 hours of coating time. Investigated surface properties are hardness, fatigue strength, and surface morphology. It was found that the optimum conditions in enhancing fatigue strength at 1.4 mbar of pressure. At these conditions, the fatigue strength increase from 401 MPa to 514 MPa, the microhardness increase from 327 VHN to 625 VHN. Based on surface morphology observation of the fracture surfaces, it shows that for raw material, an initiation crack starting from the surface. However, after being coated for 1.2 mbar, 1.4 mbar, and 1.6 mbar, the initial crack begins from the inside. The high hardness layer hinders the fatigue crack initiation.
Abstract: AISI 4340 is known as super strength steel and widely applied in military equipment, aircraft components, automotive components, drilling device and so on because of its excellent behavior in wear, corrosion, fatigue, high temperature, and high-speed operating conditions. However, due to continuing work which reduced the performance of that compone...
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Effect of Post Treatment in Argon Environment of Plasma Nitrided Local Disc Brake
Suprapto,
Tjipto Sujitno,
Ihwanul Aziz,
Wiwien Andriyanti,
Bangun Pribadi,
Emy Mulyani
Issue:
Volume 8, Issue 1, March 2019
Pages:
27-32
Received:
15 January 2019
Accepted:
20 February 2019
Published:
12 March 2019
Abstract: Plasma nitriding (also known as ion nitriding, plasma ion nitriding, or glow-discharge nitriding) is a method of surface hardening using glow-discharge technology to introduce nascent (elemental) nitrogen to the surface of a metal part subsequent diffusion into the material. Because of the formation of high compressive residual stresses in the case region, increasing surface hardness and depth parameters cause remarkable improvement in the mechanical properties of steels. In this study, the properties of a nitrided local disc brake were investigated. For that purpose, the material was nitrided at 400°C of temperature, 1.6 mbar of pressure, and 4 hours of time then followed by post-treatment in Argon (Ar) environment for various of holding time such as 10, 20, 30, 40, and 50 minutes. At these conditions the hardness increased in the range 123.1 - 223.3 VHN, the wear rate decreased in the range 21.7 × 10-9 - 3.1 × 10-9 mm3/mm kg, while before being nitrided the hardness and the wear rates were 113.5 VHN and 22.8 × 10-9 mm3/mm kg, respectively. The optimum condition for holding time during post treatments was 20 minutes. Besides that, the effect of various of N2: Ar mixture such as 90%: 10%, 80%: 20%, 70%: 30%, and 60%: 40% on the properties of local disc brake was studied. For various of gas mixing, the optimum hardness in the order of 252.7 VHN and wear rate in the order of 2.8 × 10-9 mm3/mm kg were achieved at 90%N2: 10%Ar of a gas mixture.
Abstract: Plasma nitriding (also known as ion nitriding, plasma ion nitriding, or glow-discharge nitriding) is a method of surface hardening using glow-discharge technology to introduce nascent (elemental) nitrogen to the surface of a metal part subsequent diffusion into the material. Because of the formation of high compressive residual stresses in the case...
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Effect of Quartz Particle Size on Sintering Behavior and Flexural Strength of Porcelain Tiles Made from Raw Materials in Uganda
William Ochen,
Florence Mutonyi D’ujanga,
Bosco Oruru
Issue:
Volume 8, Issue 1, March 2019
Pages:
33-40
Received:
18 January 2019
Accepted:
22 February 2019
Published:
18 March 2019
Abstract: The presence of quartz particle size (> 45 µm) has a deleterious effect on physio-mechanical properties of porcelain tiles. The effect is due to various factors including microstructure (pore) after sintering. This study aims at investigating the effect of quartz particle size (QPS) on sintering behavior and flexural strength of porcelain tiles made from raw materials in Uganda. Samples containing fine, medium and coarse QPS were pressed at 40 MPa, fired from 1150-1350°C at a firing rate of 60°C/min, and soaked for 1 hour. The influence of QPS on linear shrinkage, water absorption and flexural strength was determined. Microstructure analysis of the fired samples was carried out using Scanning Electron Microscope (SEM), and phase identification was studies using x-ray diffraction. The SEM showed large-interconnected pores for coarse QPS, and smaller-isolated pores for fine QPS. At optimum sintering temperature, samples with fine, medium and coarse QPS had values of 0.47, 0.9 and 7.1% water absorption respectively. Pressed tiles with ≤5% water absorption are classified as group BIa(porcelain tiles) and those > 0.5-≤3% as group BIb suitable as floor or wall tiles (ISO 13006). Also, the average flexural strength of 33, 18 and 8 MPa was exhibited by samples with fine, medium and coarse QPS respectively. The results indicate that only samples with fine and medium QPS satisfy the requirement ≥ 35±2 MPa and > 12 MPa for floor and wall tiles respectively (ISO 13006).
Abstract: The presence of quartz particle size (> 45 µm) has a deleterious effect on physio-mechanical properties of porcelain tiles. The effect is due to various factors including microstructure (pore) after sintering. This study aims at investigating the effect of quartz particle size (QPS) on sintering behavior and flexural strength of porcelain tiles mad...
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