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Journal articles on the topic 'Aluminyl'

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Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

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1

Hara, Naofumi, Kazuhiko Semba, and Yoshiaki Nakao. "X-Type Aluminyl Ligands for Transition-Metal Catalysis." ACS Catalysis 12, no. 3 (January 12, 2022): 1626–38. http://dx.doi.org/10.1021/acscatal.1c04340.

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2

Sorbelli, Diego, Leonardo Belpassi, and Paola Belanzoni. "What Singles out Aluminyl Anions? A Comparative Computational Study of the Carbon Dioxide Insertion Reaction in Gold–Aluminyl, −Gallyl, and −Indyl Complexes." Inorganic Chemistry 61, no. 3 (January 6, 2022): 1704–16. http://dx.doi.org/10.1021/acs.inorgchem.1c03579.

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3

Hicks, Jamie, Petra Vasko, Jose M. Goicoechea, and Simon Aldridge. "Synthesis, structure and reaction chemistry of a nucleophilic aluminyl anion." Nature 557, no. 7703 (April 16, 2018): 92–95. http://dx.doi.org/10.1038/s41586-018-0037-y.

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4

Hoobler, Preston R., Nery Villegas-Escobar, Justin M. Turney, Alejandro Toro-Labbé, and Henry F. Schaefer. "Substituent Effects on Aluminyl Anions and Derived Systems: A High-Level Theory." Journal of Physical Chemistry A 125, no. 48 (November 23, 2021): 10379–91. http://dx.doi.org/10.1021/acs.jpca.1c08918.

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5

Sorbelli, Diego, Leonardo Belpassi, and Paola Belanzoni. "Reactivity of a Gold-Aluminyl Complex with Carbon Dioxide: A Nucleophilic Gold?" Journal of the American Chemical Society 143, no. 36 (September 2, 2021): 14433–37. http://dx.doi.org/10.1021/jacs.1c06728.

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6

Hicks, Jamie, Petra Vasko, Jose M. Goicoechea, and Simon Aldridge. "Publisher Correction: Synthesis, structure and reaction chemistry of a nucleophilic aluminyl anion." Nature 560, no. 7717 (June 4, 2018): E24. http://dx.doi.org/10.1038/s41586-018-0168-1.

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7

Schwamm, Ryan J., Mathew D. Anker, Matthias Lein, and Martyn P. Coles. "Reduction vs. Addition: The Reaction of an Aluminyl Anion with 1,3,5,7‐Cyclooctatetraene." Angewandte Chemie International Edition 58, no. 5 (January 28, 2019): 1489–93. http://dx.doi.org/10.1002/anie.201811675.

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8

Anker, Mathew D., Claire L. McMullin, Nasir A. Rajabi, and Martyn P. Coles. "Carbon–Carbon Bond Forming Reactions Promoted by Aluminyl and Alumoxane Anions: Introducing the Ethenetetraolate Ligand." Angewandte Chemie 132, no. 31 (June 2, 2020): 12906–10. http://dx.doi.org/10.1002/ange.202005301.

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9

Anker, Mathew D., Claire L. McMullin, Nasir A. Rajabi, and Martyn P. Coles. "Carbon–Carbon Bond Forming Reactions Promoted by Aluminyl and Alumoxane Anions: Introducing the Ethenetetraolate Ligand." Angewandte Chemie International Edition 59, no. 31 (June 2, 2020): 12806–10. http://dx.doi.org/10.1002/anie.202005301.

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10

Kodama, Takuya. "Novel Development of Umpolung at Main Group Element: Synthesis, Structure and Reactivity of Nucleophilic Aluminyl Anion." Journal of Synthetic Organic Chemistry, Japan 77, no. 12 (December 1, 2019): 1247–49. http://dx.doi.org/10.5059/yukigoseikyokaishi.77.1247.

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11

Koshino, Kota, and Rei Kinjo. "Construction of σ-Aromatic AlB2 Ring via Borane Coupling with a Dicoordinate Cyclic (Alkyl)(Amino)Aluminyl Anion." Journal of the American Chemical Society 142, no. 19 (April 23, 2020): 9057–62. http://dx.doi.org/10.1021/jacs.0c03179.

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12

Evans, Matthew J., Mathew D. Anker, and Martyn P. Coles. "Oxidative Addition of Hydridic, Protic, and Nonpolar E–H Bonds (E = Si, P, N, or O) to an Aluminyl Anion." Inorganic Chemistry 60, no. 7 (March 16, 2021): 4772–78. http://dx.doi.org/10.1021/acs.inorgchem.0c03735.

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13

Sooksaen, Pat, and Pathompong Puathawee. "Conversion of Aluminum Dross Residue into Value-Added Ceramics." Key Engineering Materials 690 (May 2016): 71–75. http://dx.doi.org/10.4028/www.scientific.net/kem.690.71.

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This study utilized aluminum dross residue obtained from secondary process of aluminum production as the main component in the fabrication of ceramic refractories. The amount of residue varied in the range 60-90 wt% and other components in the ceramic formulations were a combination of alumino-silicate based clays. Alpha-alumina, a-Al2O3 was the main crystalline phase found in all sintered samples according to x-ray diffraction analysis. Mullite phase, Al6Si2O13 was also found in all the sintered refractories. It appeared as the main second phase which gave high strength and refractoriness. All the synthesized refractories had excellent heat-resistant characteristics when tested for thermal shock resistance. Samples were heated at 1200°C and subsequently quenched to cold water and ambient air. Refractories produced from aluminum dross residue in this study are advantageous for various applications such as high alumina bricks, high duty firebricks for steel and glass melting industry.
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14

Wittenburg, Christine, and Jean Ellen Duckworth. "Comparison of aluminum toxicology and homeopathic Alumina: a mixed methods study." International Journal of High Dilution Research - ISSN 1982-6206 17, no. 1 (July 22, 2021): 08–09. http://dx.doi.org/10.51910/ijhdr.v17i1.897.

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Toxicology forms part of homeopathy. The founder of homeopathy, Samuel Hahnemann, incorporated many toxicological symptoms in his Materia Medica. These symptoms are part of the information homeopathic practitioners relay on to choose the appropriate medication for their patients. This medication is administered in form of ultra-high dilutions. Hahnemann also developed Materia Medica on the base of provings done with high diluted substances only – simply because these substances did not have a known toxicology at his time. Alumina is one of these substances. Today we possess a reliable toxicology of aluminum and its compounds. The objective of this study was to determine the grade of concordance between homeopathic (highly diluted) Alumina and aluminum toxicology. A striking concordance will add to evidence of homeopathically potentized substances. The present was a literature-based investigation conducted from a phenomenologist stance. The design is a novel one. Symptoms of aluminum intoxication were obtained from case reports published in scholarly journals. 70 original research articles containing case-reports of 5 aluminum-induced diseases served for the extraction of over 300 symptoms. These symptoms were compared to Hahnemann´s Alumina proving symptoms. A review of modern investigations of the toxic effects of aluminum showed that the conventional medical paradigm and basic science are just starting to explore the huge number of noxious effects the metal has on human, animal and plant health. Qualitative explorations of the relevant homeopathic literature (toxicology in homeopathy and Alumina in randomized controlled trials) resulted in the finding that toxicology plays a minor role in modern homeopathy and that Alumina has been poorly investigated. The result of the quantitative part of this study – the comparison of proving and toxicology obtained from clinical cases – shows an uneven picture. It leads to only partly significant concordances between symptoms from both sources which are strong in core areas of Alumina´s remedy action while the overall comparison shows a coincidence of 50.76% (39.76% for symptoms probably produced by UHDs). This study has to be seen as a pilot for a literature-based proof of the evidence of homeopathic potencies. There remains much to be done, especially in the realm of homeopathic proving and its design. Hahnemann´s procedure – to rely on sensible provers – should be reconsidered. The reproving of Alumina should be envisaged. Keywords: Homeopathy, proving, toxicology, homeopathic pathogenetic trial (HPT), Alumina, aluminum
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15

Kim, Sung Wook, Shinji Iwamoto, and Masashi Inoue. "Pore Structure of Alumina Derived from the Alkyl Derivatives of Boehmite." Advances in Science and Technology 45 (October 2006): 2153–58. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2153.

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Solvothermal reaction of aluminum alkoxides in various alcohols at 250-300 oC yielded alkyl derivatives of boehmite (alkoxyalumoxanes; AlO(OH)1-x(OR)x) in which alkyl groups were incorporated between the boehmite layers through the covalent bondings. In the present work, pore textures of aluminas prepared by calcination of the products were examined. The alumina obtained from the ethyl derivative of boehmite had a broad pore-size distribution, while the pore-size of the alumina obtained from the dodecyl derivative of boehmite distributed in a narrow range in the mesopore region. The mode pore diameter of the latter alumina increased with the increase in calcination temperature (600 oC, 39 Å; 800 oC, 54 Å; 1000 oC, 74 Å), but narrow pore-size distribution was maintained even after calcination at high temperatures.
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16

Uribe, R., and C. Baudín. "Formación de titanato de aluminio por reacción en estado sólido de alúmina y titania." Boletín de la Sociedad Española de Cerámica y Vidrio 39, no. 2 (April 30, 2000): 221–28. http://dx.doi.org/10.3989/cyv.2000.v39.i2.867.

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17

Feret, Frank R. "Selected applications of Rietveld-XRD analysis for raw materials of the aluminum industry." Powder Diffraction 28, no. 2 (May 2, 2013): 112–23. http://dx.doi.org/10.1017/s088571561300016x.

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In the last few decades, X-ray diffraction (XRD) systems have been paramount and irreplaceable in controlling bauxite exploration, as well as Bayer and reduction processes. XRD quantitative phase analysis in the aluminum industry witnessed a steady deployment of the Rietveld method, which at present progressively replaces existing methodologies in research and plant laboratories. Rietveld analysis not only helped to surpass traditional XRD calibration methods, it also opened the door for new applications previously not possible. The use of the Rietveld method to characterize selected materials unique to the aluminum industry, such as bauxite, red mud, and alumina is demonstrated and discussed. This paper also presents how synchrotron-based diffractograms obtained for bauxite and red mud samples allowed a much better understanding of mineralogical representation, and made it possible to leverage their Rietveld quantification. Despite clear advantages, the Rietveld method also has limitations that are revealed. For alumina phase quantification, a dedicated Rietveld analytical program was built with structure data for eight alumina mineralogical phases: alpha, beta (β-Al2O3 = Na2O•11Al2O3), delta, gamma (2), kappa, sigma, and theta. The paper gives unique examples of phase quantification in aluminas of various origins and phase composition.
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18

Sooksaen, Pat, and Pathompong Puathawee. "Properties of Unglazed Ceramics Containing Aluminum Dross as a Major Component." Solid State Phenomena 266 (October 2017): 182–86. http://dx.doi.org/10.4028/www.scientific.net/ssp.266.182.

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Aluminum dross residue is a by-product produced at secondary re-melt plants where aluminum scraps are recycled. In this study, aluminum dross residue was utilized as a major component in the fabrication of unglazed ceramics for wall tile applications. The use of this by-product can reduce the landfill and environmental problems. The amount of aluminum dross residue used in the ceramic compositions varied in the range 50-90 wt.%. Other components utilized in the ceramic compositions included recycled glass alumino-silicate based clays. Firing was carried out between 1140 and 1200°C with 4h holding time which resulted in strong ceramic samples. Alpha-alumina, α-Al2O3 was the main crystalline phase found in all sintered ceramic samples. The appearance of mullite phase, Al6Si2O13 was evident in all fired samples. Overall, the synthesized ceramics had excellent densification characteristics when the amount of aluminum dross residue was less than 70 wt% in the ceramic composition.
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19

Hidayat, Kukuh, Agus Wahyudi, and Husaini Husaini. "Making a synthetic zeolite from a residue of bauxite washing." Indonesian Mining Journal 23, no. 2 (November 2020): 99–104. http://dx.doi.org/10.30556/imj.vol23.no2.2020.1112.

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A zeolite synthetic of NaA type is generally prepared by mixing the alumina and silicate-containing materials (alkali alumino hydro-silicates). The used raw materials include the amorphous solids such as metakaolin, siliceous earth, coal ash, kimberlite waste, alumina trihydrate [Al(OH)3], bauxite, and aluminum metal. Residue of bauxite washing retains a fine texture and contains significant alumina and silica content, namely 30-36% Al2O3 and 10-15% SiO2. Both components are required for making the zeolite NaA . In this research, the zeolite NaA was made by extracting the alumina from residue of bauxite washing with caustic soda, and followed by reacting it with a water glass after through the flushing and washing process. The composition of zeolite NaA is as follows: 33.87% SiO2, 27.63% Al2O3, 16.31% Na2O, and 22.18% H2O with Na96Al96Si96O384.216H2O or Na12(AlO2)12(SiO2)12.27H2O as its mineral composition.
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20

Gromov, Nalivaiko, Ambaryan, Vlaskin, Buryakovskaya, Kislenko, Zhuk, et al. "Aluminum–Alumina Composites: Part Ⅰ: Obtaining and Characterization of Powders." Materials 12, no. 19 (September 27, 2019): 3180. http://dx.doi.org/10.3390/ma12193180.

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The process of advanced aluminum-alumina powders production for selective laser melting was studied. The economically effective method of obtaining aluminum–alumina powdery composites for further selective laser melting was comprehensively studied. The aluminum powders with 10–20 wt. % alumina content were obtained by oxidation of aluminum in water. Aluminum oxidation was carried out at ≤200 °C. The oxidized powders were further dried at 120 °C and calcined at 600 °C. Four oxidation modes with different process temperatures (120–200 °C) and pressures (0.15–1.80 MPa) were investigated. Parameters of aluminum powders oxidation to obtain composites with 10.0, 14.5, 17.4, and 20.0 wt. % alumina have been determined. The alumina content, particle morphology, and particle size distribution for the obtained aluminum–alumina powdery composites were studied by XRD, SEM, laser diffraction, and volumetric methods. According to the obtained characteristics of aluminum–alumina powdery composites, they are suitable for the SLM process.
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21

Kobayashi, Yoshio, Yusuke Mabuchi, Masachika Hama, Katsumi Yamamura, Yusuke Yasuda, and Toshiaki Morita. "Effects of Seeding with Nanocrystallites and Addition of Inorganic Alumina Sol on Crystallization of Alkoxide Alumina Gel." Key Engineering Materials 697 (July 2016): 12–17. http://dx.doi.org/10.4028/www.scientific.net/kem.697.12.

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This paper reports a method for producing α-Al2O3 at low temperature from aluminum alkoxide using a combination of seeding of α-Al2O3 nanocryatallites and adding of inorganic alumina sol. An alkoxide alumina sol was obtained by hydrolyzing aluminum isopropoxide in water at 80°C and then peptizing the hydrolyzed aluminum isopropoxide using acetic acid at 80°C. An inorganic alumina sol was obtained by producing aluminum compound with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution and then peptizing the aluminum compound using acetic acid at room temperature. α-Al2O3 nanocrystallites were added to the alkoxide alumina sol containing the inorganic alumina sol. The addition of inorganic alumina sol provided successful fabrication of a crack-free α-Al2O3-seded alumina film by a spin-coating technique. The sol containing α-Al2O3 nanocrystallites was transformed to an α-Al2O3-seeded alumina gel by drying the sol at room temperature. The non-seeded alumina gel was crystallized into γ-Al2O3 at a temperature below 900°C. In contrast, the alumina seeded at 1% α-Al2O3 nanocrystallites content began to be transformed to α-Al2O3 by annealing at the temperature. The seeding and the adding promoted crystallization of the alumina gel into α-Al2O3. The promotion of crystallization was significant with an increase in α-Al2O3 nanocrystallites content by weight in the final seeded alumina gel.
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22

Galusková, Dagmar, Miroslav Hnatko, Jozef Kraxner, Dušan Galusek, and Pavol Šajgalík. "Influence of Calcium Addition on the Chemical Durability of the Model Alumino-Silicate Glasses in Aqueous Solutions." Key Engineering Materials 512-515 (June 2012): 1009–14. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.1009.

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The corrosion resistance of liquid phase sintered (LPS) alumina ceramics in aqueous environments strongly depends on composition and chemistry of grain boundary glass formed during sintering. The chemical durability of model alumino-silicate glasses with various contents of CaO in aqueous solutions was therefore evaluated. Prepared glasses were corroded under hydrothermal conditions in deionized water under static conditions. The examination of surface morphology of corroded specimens after the contact with deionized water, together with the analysis of corrosion solution provided information on mechanism of dissolution of grain boundary glasses in LPS aluminas and confirmed that dissolution process is hindered due to saturation of solution with respect to leached elements. The initial dissolution rates for studied glasses were determined. The results are applicable for optimization and enhancement of corrosion resistance of LPS alumina under hydrothermal conditions.
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23

Yin, Jian Jun, Min Li, Zhong Dong Zhang, Dong Wang, Shuai Shao, and Xiong Hou Gao. "The Preparation of High Alumina Content Alumina Sol." Applied Mechanics and Materials 528 (February 2014): 118–26. http://dx.doi.org/10.4028/www.scientific.net/amm.528.118.

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The alumina sol with high content of Al2O3 was prepared by peptizing aluminum hydroxide powder. The properties of the alumina sol were characterized by Fourier transform-infrared (FT-IR) spectrum, zeta potential analyzer, X-ray diffraction (XRD) and Transmission electron microscope (TEM). The results show that the sol with high content of Al2O3 can be easily prepared by peptizing the soluble aluminum hydroxide powder, the smaller of the size of aluminum hydroxide powder, the higher of the aluminum content of the alumina sol. Two-step peptization process is optimum, the effect of peptization aluminum hydroxide powder using AlCl3 :HCl=1:4 solution as peptizer is best, the alumina sol sample with pH value of 2.5 and alumina content 11% had good stability. A great application potential of the high alumina content sol has been displayed in preparing FCC catalysts.
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24

Takano, H., Takafumi Kusunose, Tohru Sekino, Rajagopalan Ramaseshan, and Koichi Niihara. "Development of Low Machining Cost Materials by Using Aluminum Borate." Key Engineering Materials 317-318 (August 2006): 335–38. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.335.

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6061 aluminum alloy composite reinforced with α-alumina and aluminum borate is fabricated by casting method. The above mentioned composite has been compared to a similar composite without aluminum borate reinforcement for their machinability. The aluminum borate filler was controlled up to (2.5, 5.0 and 30vol %) on the surface of α-alumina. The reaction zone between alumina and the matrix in both the systems are analyzed with the help of TEM micrographs as well as X-ray diffraction profiles. At the reaction zone between alumina and the aluminum alloys, some spinel-like compounds (MgAl2O4) are identified. Finally, machinability was analyzed with the single point tool machining.
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25

Díaz, Isabel, Verónica González-Peña, Carlos Márquez-Alvarez, and Joaquín Pérez-Pariente. "Transmission Electron Microscopy Study of the Porous Structure of Aluminas Synthesized by Non-Ionic Surfactant Templating Route." Collection of Czechoslovak Chemical Communications 68, no. 10 (2003): 1937–48. http://dx.doi.org/10.1135/cccc20031937.

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Organized mesoporous and microporous aluminas have been synthesized by a sol-gel route in non-aqueous media using poly(oxyethylene) block polymers as directing agents. Gel compositions adjusted to obtain direct micelles (in 1,4-dioxane solution) and reverse micelles (in cyclohexane solution) were tested. The influence of synthesis conditions, such as temperature, solvent, use of additives or chemical modification of the precursor, on the alumina porous structure has been analysed by transmission electron microscopy (TEM). Mesoporous aluminas with a pore structure originated by the cross-linking of corrugated oxide-hydroxide platelets of nanometric size were obtained using aluminum sec-butoxide as precursor. The addition of ammonium fluoride or amines to the synthesis gel, as well as higher calcination temperatures, caused a decrease in the surface area due to the condensation of the crystallites into a dense porous structure composed of small polycrystalline agglomerates. Microporous aluminas with higher density and a disordered but isotropic porous structure were obtained by chemical modification of the alkoxide precursor with chelating agents such as ethyl acetoacetate or triethanolamine.
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26

Wu, Dao Ji, Ding Li, Li Rui Weng, Wei Jie Zheng, and Xiao Yan Qu. "The Regenerative Experiment of Activated Alumina Granules." Advanced Materials Research 201-203 (February 2011): 2649–52. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.2649.

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Activated alumina granules is a primary sorption media . The intention of this experiment is to get out of the difference between the different regenerate medias, caustic soda and alumina sulfate . Experimental result shows the renewal adsorption capacity of activated alumina using caustic soda regenerate is more than using aluminum sulfate .Under the same experiment condition ,aluminum sulfate can regain 13.27mg/g adsorption capacity while using 0.8 per cent caustic soda to regenerate alumina and 5.36mg/g using 4 per cent aluminum sulfate .The intensity of activated alumina granules reduces when we use caustic soda as regenerate media .The mass wastage of activated alumina granules is between 12% and 14% using caustic soda as regenerate media and between 6% and 8%uing aluminum sulfate .It is needed to neutralized by hydrochloric acid or aluminum sulfate after regenerated by caustic soda .Without neutralized, the concentration of treated water is over 1.0mg/l in the beginning.And neutralized with hydrochloric acid or aluminum sulfate, the efficacious run time can achieve 23 hours and 31hours .
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27

Padilla, Isabel, Aurora López-Delgado, Sol López-Andrés, Marta Álvarez, Roberto Galindo, and Alfonso J. Vazquez-Vaamonde. "The Application of Thermal Solar Energy to High Temperature Processes: Case Study of the Synthesis of Alumina from Boehmite." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/825745.

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The aim of this paper is to evaluate the feasibility of obtaining alumina from boehmite using a free, clean, and unlimited power source as the solar energy. Boehmite was obtained by hydrothermal treatment of a hazardous waste coming from aluminum slag milling. The waste is considered as a hazardous substance because of it releasing toxic gases (hydrogen, ammonia, methane, and hydrogen sulfide) in the presence of water. The as-obtained boehmite was transformed into alumina, in air atmosphere, using a solar energy concentrator (Fresnel lens). The solar installation provides a power density of 260 W·cm−2which allows reaching temperatures upper than 1000°C at few minutes of exposure. Tests were performed at different periods of time that ranged between 5 and 90 min. The percentage of transformation of boehmite into alumina was followed by the water content of samples after solar radiation exposure. Samples were characterized by X-ray diffraction, infrared spectroscopy, and thermogravimetry. Metastable aluminas started to appear at 5 min and the crystalline and stable phase corundum at 10 min of solar radiation exposure.
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28

Abdulkader, Niveen J., Payman Sahbah Ahmed, and Mohammed Mahdy Jabar. "Study Corrosion Behavior of Alumina Particulate / (AA6061) Aluminum Metal Matrix Composite In Marine Environment." Sulaimani Journal for Engineering Sciences 3, no. 3 (April 1, 2016): 30–36. http://dx.doi.org/10.17656/sjes.10034.

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29

Dubey, Swati, Madhu Agrawal, and Akhilendra Bhushan Gupta. "Advances in coagulation technique for treatment of fluoride-contaminated water: a critical review." Reviews in Chemical Engineering 35, no. 1 (December 19, 2018): 109–37. http://dx.doi.org/10.1515/revce-2017-0043.

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Abstract Fluoride contamination of groundwater has become a major concern worldwide, resulting in serious medical conditions such as dental and skeletal fluorosis. Consequently, the WHO recommends that drinking water should not contain more than 1.5 mg/l of fluoride. Various defluoridation techniques such as coagulation, reverse osmosis, activated alumina adsorption, and biosorbent adsorption have been developed. Adsorption through the activated alumina and biosorbent process is not cost effective and has regeneration problems, and the reverse osmosis process has the high initial cost which makes it unacceptable for developing countries. Coagulation is a commonly employed field technology for defluoridation, which involves the addition of aluminum salts, lime, and bleaching powder followed by rapid mixing, flocculation, sedimentation, and filtration but suffers from a limitation of high residual aluminum in treated water. This paper critically reviews the recent developments in the coagulation technique for defluoridation along with its comparison to other defluoridation techniques. The review describes the pertinent gaps in the process and throws open suggestions for extending research by citing the recent studies which may lead to the revival of the process. The description about the suspension of alumino-fluoro complexes that constitute a substantial part of the residual aluminum after alum treatment has been narrated in the paper that helps in a deeper understanding of the defluoridation mechanism. To make the process highly suitable for communities, appropriate technological interventions, such as converting it to a continuous mode of operation, replacing alum with poly-aluminum chloride (PAC), and attaching a micro-filtration unit in series of the existing process, can be done. Also, using PAC as a coagulant with sand filtration has to be considered for making the process more efficient.
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30

Becker, Lillian C., Ivan Boyer, Wilma F. Bergfeld, Donald V. Belsito, Ronald A. Hill, Curtis D. Klaassen, Daniel C. Liebler, et al. "Safety Assessment of Alumina and Aluminum Hydroxide as Used in Cosmetics." International Journal of Toxicology 35, no. 3_suppl (November 2016): 16S—33S. http://dx.doi.org/10.1177/1091581816677948.

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This is a safety assessment of alumina and aluminum hydroxide as used in cosmetics. Alumina functions as an abrasive, absorbent, anticaking agent, bulking agent, and opacifying agent. Aluminum hydroxide functions as a buffering agent, corrosion inhibitor, and pH adjuster. The Food and Drug Administration (FDA) evaluated the safe use of alumina in several medical devices and aluminum hydroxide in over-the-counter drugs, which included a review of human and animal safety data. The Cosmetic Ingredient Review (CIR) Expert Panel considered the FDA evaluations as part of the basis for determining the safety of these ingredients as used in cosmetics. Alumina used in cosmetics is essentially the same as that used in medical devices. This safety assessment does not include metallic or elemental aluminum as a cosmetic ingredient. The CIR Expert Panel concluded that alumina and aluminum hydroxide are safe in the present practices of use and concentration described in this safety assessment.
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31

Cao, Hui Qin, Ji Luo, and Wei Wei Yang. "Preparation of Dispersion Strengthened Aluminum Alloy by High Energy Ball Milling." Advanced Materials Research 602-604 (December 2012): 598–601. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.598.

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In order to develop a high-strength aluminum alloy, alumina dispersion strengthened aluminum alloy was prepared by high energy ball milling on 2024 aluminum alloy powder in ethanol. The microstructure, particle size and distribution of the Al2O3 particles in the alloy were analyzed by FE-SEM; the mechanical properties were investigated. Results showed that alumina dispersion strengthened aluminum alloy was prepared successfully by high energy ball milling, the Al2O3 particles of several tens of nm in diameter were homogeneously distributed in the matrix grain and the spatial distance between particles was about 50-100nm. The yield strength and elongation of alumina oxide dispersion strengthened aluminum alloy were 489MPa and 7.9%.
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32

Zhou, Tian Pei. "Application of Intelligent Characteristic Model in Alumina Concentration Control System." Advanced Materials Research 328-330 (September 2011): 1837–40. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1837.

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In electrolytic aluminum production processing, the measurement and control of alumina density is one of the three most important control aims. However, due to alumina density can not be measured directly and continuously online, and electrolytic aluminum production process is nonlinear, time-varying and large delay, which can not be described through the mathematical analysis model. Therefore, efficient and reliable development of alumina density control method is very important. In this paper, alumina density is controlled by single neural adaptive PID controller in electrolytic aluminum production processing, and alumina density based on intelligent characteristic model is established by using the intelligent characteristic model method, takes the model as the control model, alumina density is controlled combination of the two advantage, which achieve a good control effect.
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33

Gralik, Guilherme, Adriana Scoton Antonio Chinelatto, and Adilson Luiz Chinelatto. "Total and Partial Replacement of Quartz in Aluminum Hydroxides Porcelain Formulations." Materials Science Forum 798-799 (June 2014): 289–93. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.289.

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Alumina has been studied as a substitute for quartz triaxial porcelain formulations, but the high cost of the alumina raises the cost of production. The use of aluminum hydroxide from the Bayer process for obtaining aluminum, a source of alumina, is an alternative to alumina. In this work we used two aluminum hydroxides to replace the quartz composition of triaxial porcelain. The raw materials used were characterized by analysis of particle size distribution, scanning electron microscopy, diffraction and X-ray fluorescence. The compositions sintered were characterized by apparent density, apparent porosity, water absorption, flexural strength, and X-ray diffraction and scanning electron microscopy. Both the total and partial replacement of quartz by aluminum hydroxide showed good results with high flexural strength, low water absorption and low porosity.
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34

Oh, Han Jun, Kyung Wook Jang, Jong Ho Lee, Beom Su Ki, Chang Hoe Heo, So Hyun Kwon, and Choong Soo Chi. "Effects of Annealing Treatment of Aluminum Substrate on Nanopore Arrangements in Anodic Alumina." Solid State Phenomena 118 (December 2006): 549–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.118.549.

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Effects of annealing treatments of aluminum substrate for ordered nanopore arrays formed by self-organized anodization have been investigated. To observe the relationship between microstructures of aluminum substrate and nanopore regularity formed after anodization of the aluminum substrate, aluminum specimens were annealed at 300, 400, and 500 °C. The anodic alumina layer was prepared by two-step anodizing process in oxalic acid at 40 V. The ordered arrays of nanopore on anodic alumina were shown to be strongly dependent on the annealing conditions, and nanopore regularity on alumina template increased with increasing annealing temperature and time.
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35

Bin Mokaizh, Aiman A., Jun Haslinda Shariffuddin, Abdullah O. Baarimah, Amin Al-Fakih, Abdullah Mohamed, Salem O. Baarimah, Al-Baraa Abdulrahman Al-Mekhlafi, Hamoud Alenezi, Olusegun Abayomi Olalere, and Anwar Ameen Hezam Saeed. "Elucidating the Effects of Reaction Time on the Physicochemical Characterization of Valorized Synthesized Alumina." Materials 15, no. 9 (April 22, 2022): 3046. http://dx.doi.org/10.3390/ma15093046.

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Aluminum waste-can management in Malaysia has recently become a serious environmental and public health issue, particularly in metropolitan areas. This has prompted the need to valorize these waste-cans into value-added products using the most economical and environmentally friendly techniques. In this study, the sol–gel technique was used to synthesize high-quality alumina from the aluminum waste-cans collected. From this method, the observed peaks of the synthesized alumina were identified as diaspore (α-AlO(OH)), boehmite (γ-AlO(OH)), aluminum oxide, or gamma-alumina (γ-Al2O3) crystalline structure and corundum. The morphological configuration, microstructure, and functional group properties of the synthesized alumina were evaluated. All the synthesized alumina exhibited a non-spherical shape and appeared to have hexagonal-like shape particles. Moreover, the XRD patterns of the synthesized alumina AL-6-30 and AL-12-30 exhibited a small angle (1–10°) with no XRD peak, which indicated a mesoporous pore structure with no long-range order. The overall results of γ-alumina synthesized from the aluminum waste-cans showed an optimal condition in producing a highly structured γ-alumina with excellent surface-area characteristics. The synthesized alumina exhibited stronger and highly crystalline functional characteristics almost comparable with the commercially available brands on the market.
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36

Zhang, Jun, Hua Bo Li, and Yong Hua Duan. "A Facile and Reliable Preparing Route of Brown Fused Alumina from Aluminum Dross." Key Engineering Materials 680 (February 2016): 335–38. http://dx.doi.org/10.4028/www.scientific.net/kem.680.335.

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Aluminum dross is the staple solid waste in electrolytic aluminum industry. Taking full advantage of the aluminum dross is of great significance for controlling environmental pollution and saving resource. In this work, brown fused alumina is successfully prepared using aluminum dross as raw material through different pretreatments for aluminum dross. The results show that the brown fused alumina product is comprised of α-Al2O3 (ca.95%), NaCl (ca.1~3%) and CaF2 (ca.1~3%), and contents of the other components are as follows: MgO 0.33%, SiO2 1.12%, Fe2O3 0.41%, CaO 0.58%, TiO2 0.13%, K2O 0.05%, Na2O 0.87% and V2O5 0.92%. This quality of the resulting brown fused alumina can fully meet the national standards of China (GB/T 2478-2008).
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37

He, Song, Yanmei Zhang, Wansheng Yang, Zhangyuan Wang, Xudong Zhao, and Pingnuo Wang. "Investigation on the Solar Absorption Property of the Nanoporous Alumina Sheet for Solar Application." Materials 12, no. 14 (July 22, 2019): 2329. http://dx.doi.org/10.3390/ma12142329.

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In order to improve the absorption performance of the aluminum sheet for solar application, the nanoporous alumina sheets with the pore diameters of 30 nm and 400 nm were prepared by the anodic oxidation method. The absorption properties of the nanoporous alumina sheets under different solar radiation intensity were studied and compared with the conventional polished aluminum sheet. The results showed that the average absorptivity of the aluminum sheets decreased with the increase of the radiation intensity. When the radiation intensity was 100 W/m2, the nanoporous alumina sheet with the 30 nm pore diameter had the highest average solar absorptivity of 0.39, which was 18% higher than that of the nanoporous alumina sheet with 400 nm pore diameter, and 50% higher than that of the polished aluminum sheet. The maximum instantaneous absorption efficiency of the nanoporous alumina sheet with 30 nm pore diameter was found at 0.92 when the radiation intensity was 100 W/m2. The testing results indicated that the nanoporous alumina sheet with the 30 nm pore diameter performed the best compared with the other two aluminum sheets. By error propagation analysis, the relative error of the average amount of heat absorption and the average absorptivity were acceptable.
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38

Rabia, A. R., A. H. Ibrahim, and N. N. Zulkepli. "Activated alumina preparation and characterization: The review on recent advancement." E3S Web of Conferences 34 (2018): 02049. http://dx.doi.org/10.1051/e3sconf/20183402049.

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Aluminum and aluminum based material are significant industrial materials synthesis because of their abandonment, low weight and high-quality corrosion resistance. The most advances in aluminum processing are the ability to synthesize it’s under suitable chemical composition and conditions, a porous structure can be formed on the surface. Activated alumina particles (AAP) synthesized by the electrochemically process from aluminum have gained serious attention, inexpensive material that can be employed for water filtration due to its active surface. Thus, the paper present a review study based on recent progress and advances in synthesizing activated alumina, various techniques currently being used in preparing activated alumina and its characteristics are studied and summarized
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39

Nurrudin, Ahmad, Brian Yuliarto, Suyatman, and Agung Sriwongo. "Formation of Porous Anodic Alumina from Impure Aluminum Foil in Inorganic Acids." Advanced Materials Research 1112 (July 2015): 89–93. http://dx.doi.org/10.4028/www.scientific.net/amr.1112.89.

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The morphology of porous anodic alumina (PAA) formed by anodizing in inorganic electrolytes is reported. An impure aluminum was anodized in sulfuric acid, phosphoric acid and chromic acidat room temperature with a constant applied potential 2 – 30 V. The formation of porous anodic alumina was carried out by one and two steps anodization. It is clearly noted that anodizing impure aluminum at room temperature provide higher kinetic of oxide dissolution compared to oxide growth. Two steps anodizing aluminum in sulfate electrolyte always resulted in random porous alumina, while phosphate electrolyte provided strong anodization producing irregular porous alumina with average diameter of 61.6 nm. Two steps anodizing aluminum in chromate electrolyte produce better pore ordering with relatively large size pore distributions. The average pore diameter of alumina increases linearly with applied voltage, with proportionality factor lp 0.83 nmV-1. Annealing the sample increased the interpore distance, removed stresses providing lower activation energy for pore formation.
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40

Roy, Matthew M. D., Andreas Heilmann, Mathias A. Ellwanger, and Simon Aldridge. "Generation of a π‐Bonded Isomer of [P 4 ] 4− by Aluminyl Reduction of White Phosphorus and its Ammonolysis to PH 3." Angewandte Chemie International Edition 60, no. 51 (November 10, 2021): 26550–54. http://dx.doi.org/10.1002/anie.202112515.

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41

Roy, Matthew M. D., Andreas Heilmann, Mathias A. Ellwanger, and Simon Aldridge. "Generation of a π‐Bonded Isomer of [P 4 ] 4− by Aluminyl Reduction of White Phosphorus and its Ammonolysis to PH 3." Angewandte Chemie 133, no. 51 (November 10, 2021): 26754–58. http://dx.doi.org/10.1002/ange.202112515.

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42

Mizushima, Yasuyuki, Makoto Hori, and Minoru Sasaki. "27Al MAS-NMR spectra of alumina aerogels." Journal of Materials Research 8, no. 9 (September 1993): 2109–11. http://dx.doi.org/10.1557/jmr.1993.2109.

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The 27Al MAS-NMR spectra of alumina aerogels were determined. The spectra showed different profiles according to the supercritical methods used during drying. The alumina aerogel supercritically dried in a CO2 extractor (80 °C, 15.7 MPa) displayed a pentahedral-coordinated aluminum structure. On the other hand, the alumina aerogel supercritically dried in an autoclave (270 °C, 26.5 MPa) revealed no pentahedral-coordinated aluminum structure. The absence of pentahedral-coordinated aluminum was one factor for the lower temperature of transformation from the γ to the θ phase.
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43

Jung, Young Mi, and Sang Woo Kim. "Effect of Magnesium Addition on the Phase Transformation of α-Alumina Prepared from Route of Ammonium Aluminum Carbonate Hydroxide." Solid State Phenomena 135 (February 2008): 139–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.135.139.

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Effect of magnesium addition on rapid transformation of α-alumina prepared from route of ammonium aluminum carbonate hydroxide during thermal heating and microwave radiation heating was investigated. The phase transformation and the final particle size of the transient alumina composite powder were significantly affected by amount of magnesium added in the aluminum precursor during the microwave radiation heating in various environmental atmospheres. Rapid transformation from γ- to α-phase was found in the magnesium added transient alumina by microwave-assisted transformation and nano-sized α-alumina was obtained. When the 3 wt% magnesium added ammonium aluminum carbonate hydroxide was heated by microwave radiation under nitrogen atmosphere, the transformation temperature from γ- to α-alumina was considerably lowered to 1000°C and the average particle size of 27.6 nm was attained for the α-alumina-spinel composite powder.
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44

Gralik, G., A. L. Chinelattot, and A. S. A. Chinelatto. "Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain." Cerâmica 60, no. 356 (December 2014): 471–81. http://dx.doi.org/10.1590/s0366-69132014000400004.

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Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydroxide, reprecipitated aluminum hydroxide. Compositions with commercial alumina and quartz were also formulated to better understand the effects of adding these alternative materials. The raw materials were milled, dried, and characterized by analysis of the particle size distribution, X-ray diffraction, and X-ray fluorescence. The compositions were formulated by replacing the different sources of alumina in the formulation of porcelain. The compositions studied were shaped by pressing and sintered at different temperatures (1150-1400 ºC). The results showed that the use of bauxite and aluminum hydroxide as an alternative source of Al2O3 is viable. The impurities contained in refractory bauxite contributed to the lower values of flexural strength found in compositions having refractory bauxite as a source of alumina. The compositions with reprecipitated aluminum hydroxide showed a high mechanical resistance at low sintering temperatures, while compositions with aluminum hydroxide obtained by the Bayer process achieved good results of mechanical strength in a wide temperature range.
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45

Li, Ya Nan, Wei Zheng Zhang, Yuan Fu Cao, and Ti En Zhang. "Properties and Application of Alumina Reinforced Aluminum Composite." Advanced Materials Research 853 (December 2013): 68–72. http://dx.doi.org/10.4028/www.scientific.net/amr.853.68.

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Improving high-temperature strength of aluminum piston material is a core technology for diesel engines to high speed and high intensity. To figure out the influence of alumina reinforced aluminum composites to the thermal load of high intensity piston, this paper study the properties of the alumina fiber reinforced aluminum composite and its protection for piston. The research shows that, compared with the cast aluminum, the high tensile strength and fatigue limit of the composite were increased by about 25% and 26% respectively. Therefore, the alumina fiber reinforced composite could not improve the temperature distribution of the piston, but it can improve high temperature strength and the operational reliability of the piston.
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46

Sang, Ke Zheng, Rui An, Zhi Wen Huang, Hong Wei Li, and Jun-Ichi Matsushita. "Effect of Silica on the Wettability and Composition of the Alumina/Aluminum Interface." Materials Science Forum 868 (August 2016): 68–72. http://dx.doi.org/10.4028/www.scientific.net/msf.868.68.

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In order to improve the wetting ability of metal to ceramic, silica coatings on alumina/ mullite ceramics were prepared with tetraethyl orthosilicate (TEOS) by sol-gel method. The preparation processing was optimized. Furthermore, the interactions between the aluminum melt and the ceramic with or without silica coating were investigated. The results showed that the silica coatings could be successfully prepared. The molten aluminum melt reacted with silica, and alumina was formed at the interface between ceramic and metal. The ceramic (alumina/ mullite) substrates could be infiltrated by aluminum melts due to the existence of mullite. The silica coatings conduced to the infiltration and improved the combination between the ceramic and aluminum at the interface.
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47

Al-Zuhairi, Haitham Mohammed Ibrahim, Iqbal Alshalal, Auday Awad Abtan, Baha Sami Mahdi, and Muna Khalil Asmail. "Influence of the mold type on the mechanical properties of the piston alloy with nano alumina in casting and metal mold." Eastern-European Journal of Enterprise Technologies 5, no. 12 (119) (October 30, 2022): 21–30. http://dx.doi.org/10.15587/1729-4061.2022.266263.

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This research is an experimental comparison study to show the influence of mold type casting on mechanical properties. The study considers the aluminum alloy of a gasoline engine piston with nanoparticles alumina Al2O3 size 25 nm manufactured in two types of molds. Sand mold and cast-iron mold were selected to cast the aluminum composite components. A systematic comparative study of tensile strength and hardness properties of cast aluminum components is made on sand and metal molds production. The nano powder can add to enhance the mechanical properties must not exceed 4 % for metal and sand mold casting. According to data for hardness, adding nano alumina powder has minimal impact on metal mold casting, but it significantly improves sand casting. From a financial standpoint, metal casting provides higher economic values for making piston aluminum castings. The hardness rises as the alumina content does in two molds as compared to the obtained specimen. It demonstrates that the highest hardness occurs at 4 % alumina in the sand-casting mold and at 6 % alumina in the metal. When the compositions of the casting materials are the same, a comparison of the fracture morphology between sand and mold casting reveals more ductile fractures for metal molds compared to brittle fractures in sand cast by large silicon separation grains because of higher grain growth in sand casting by longer solidification time. The same is seen in mold casting, which exhibits reduced ductility due to the alumina nanoparticles' dispersion strengthening process in the aluminum matrix. This arises as a result of nano alumina dispersion acting as barriers to dislocation motions in the aluminum matrix, enhancing strength but reducing ductility.
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48

Hamritha, S., M. Shilpa, M. R. Shivakumar, G. Madhoo, Y. P. Harshini, and Harshith. "Study of Mechanical and Tribological Behavior of Aluminium Metal Matrix Composite Reinforced with Alumina." Materials Science Forum 1019 (January 2021): 44–50. http://dx.doi.org/10.4028/www.scientific.net/msf.1019.44.

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Aluminium alloy has gained importance in the automotive and aerospace industry as it is easily available and easy in manufacturing. In the recent years, materials science has gained huge importance in the field of composites. In the field of composites metal matrix composite is playing a lead role in industrial applications. The unique combinations of properties provided by aluminum and its alloys make aluminum one of the most versatile, economical and attractive metallic materials. To enhance the properties of aluminum, it has been reinforced with alumina, silicon carbide, graphene and others. In this study, A357 aluminum has been strengthened by using different weight percent of alumina as reinforcement. Percentage of alumina used are 4%, 8% and 12% to enhance the mechanical and tribological property of A357.The fabricated samples were studied to understand the performance of the composite for mechanical and tribological characters. It was observed that the composites showed superior properties compared to the base material. Statistical analysis i.e. regression analysis has been carried out for hardness and tensile strength of alumina reinforced aluminum composite.
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49

Jin, Jing Yun, Zai Yuan Li, and Yan Wu. "Extraction of Aluminum from High Iron Bauxite by Carbothermal Reduction-Ammonium Sulfate Roasting." Applied Mechanics and Materials 624 (August 2014): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amm.624.3.

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A new preparation of alumina from high iron bauxite, which has not been being made reasonably use of yet, has been studied. Iron in high iron bauxite was removed by carbothermal reduction and aluminum-rich slag could be obtained. Then aluminum was extracted from aluminum-rich slag by ammonium sulfate roasting. After leaching, Al2(SO4)3 was obtained, which can be used for preparation of alumina. The effects of roasting temperature, roasting time, ammonium sulfate/aluminum-rich slag mass ratio were investigated. Optimum roasting conditions from aluminum-rich slag by ammonium sulfate were found as roasting temperature:400°C;roasting time:120min;ammonium sulfate/aluminum-rich slag mass ratio:6. Approximately 98% of aluminum was effectively extracted.
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50

Kim, Sang Woo, and Young Mi Jung. "Nanocrystalline Particle Coatings on α-Alumina Powders by a Carbonate Precipitation and Thermal-Assisted Combustion Route." Journal of Nanoscience and Nanotechnology 7, no. 11 (November 1, 2007): 3906–9. http://dx.doi.org/10.1166/jnn.2007.082.

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We have suggested ultrafine particle coating processes for preparing nanocrystalline particle coated α-alumina powders by a carbonate precipitation and thermal-assisted combustion route, which is environmentally friendly. The nanometric ammonium aluminum carbonate hydroxide (AACH) as a precursor for coating of alumina was produced from precipitation reaction of ammonium aluminum sulfate and ammonium hydrogen carbonate. The synthetic crystalline size and morphology were greatly dependent on pH and temperature. By adding ammonium aluminum sulfate solution dispersed the α-alumina core particle in the ammonium hydrogen carbonate aqueous solution, nanometric AACHwith a size of 5 nm was tightly bonded and uniformly coated on the core powder due to formation of surface complexes by the adsorption of carbonates, hydroxyl and ammonia groups on the surface of aluminum oxide. The synthetic precursor rapidly converted to amorphous- and γ-alumina phase without significant change in the morphological features through decomposition of surface complexes and thermal-assisted phase transformation. As a result, the nanocrystalline polymorphic particle coated α-alumina core powders with highly uniform distribution were prepared from the route of carbonate precipitation and thermal-assisted combustion.
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