Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 37 )

2018 ( 123 )

2017 ( 142 )

2016 ( 169 )

Custom range...

Search Results: 1 - 10 of 4680 matches for " Alumina layer "
All listed articles are free for downloading (OA Articles)
Page 1 /4680
Display every page Item
Capillary pressure driven water movement in wet unsaturated porous media: effect of particle electric charge
Sánchez, Rosa M. Torres;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000200023
Abstract: experiments of water flow using a non saturated porous medium constituted by different α- wet unsaturated alumina systems indicate that particle surface charge decreased the amount of water moved. maximum water movement occurred when surface charge was zero. water movement was affected by thickness of the electrical double layer at ph where particles have net charge (out of the iepph). these results suggest charge-induced structuring of water adjacent to charged particle surfaces.
Anodization of cast aluminium alloys produced by different casting methods
K. Labisz,L.A. Dobrzański,J. Konieczny
Archives of Foundry Engineering , 2008,
Abstract: In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.
Fabrication of Alumina Nano-fibers from PAAO

PAN Jin-Zhi,ZHAO Hong,CHEN Chun-Huan,LI Guo-Jun,REN Rui-Ming,

无机材料学报 , 2006,
Abstract: Based on PAAO's unique cellular hexagon morphology and composition, various alumina fibers (nano-belts, nano-rods, and nano-tubes) were fabricated by simply employing a dilute acid etching method. Scanning electron microscope (SEM) incorporated with energy dispersive X-ray spectroscope (EDS) and transmission electron microscope (TEM) were applied to characterize these nano-fibers. It is proved that alumina nano-fibers are formed from the porous layer, while totally different behaviors of the barrier layer and the porous layer are showed during the etching process. The orientated etching, resulted from PAAO's particular morphology and composition, is believed to be the main reason that explains the formation of different alumina nano-fibers.
Retention behaviour of some estradiol derivatives on alumina in normal phase chromatography
Journal of the Serbian Chemical Society , 2003,
Abstract: The retention constants of variously substituted estradiol derivatives were measured as a function of the composition of various binary mobile phases in order to study the relationship between chemical structure and retention behaviour in TLC on alumina. The slopes and intercepts of the linear relationships between the retention constant RM and the logarithm of the volume fraction of the polar mobile phase component were calculated and are discussed in relation to the characteristics of the solute and mobile phase. The RFvalues and relative retention DRM of the compounds depend largely on the retention behaviour of their substituents. The results obtained in this investigation are compared with the results of the same derivatives obtained in previous investigations on silica gel.
Electrochemical Self-Assembly of Nanoporous Alumina Templates Title  [PDF]
Muna Moussa Abbas
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.35035
Abstract: Porous alumina was fabricated electrochemically through anodic oxidation of aluminum by means of such a self-organized method. Anodic aluminium oxide (AAO) template with nanopores was grown by two-steps anodization processes from a high purity aluminium foil. The anodization process was carried out in a phosphoric acid electrolyte at ambient temperature with a different duration of anodization. The analysis observation by Atomic Force Microscopy (AFM) showed that nanopore size increased with anodization time. The nanopore sizes of porous alumina were (16.04, 26.19 and 37.39 nm) for (1, 2 and 3 hour) respectively.
A method of color modulation based on porous alumina and atomic layer deposition

Wang Xu-Long-Qi,Zhang Dong-Xian,Zhang Hai-Jun,

物理学报 , 2011,
Abstract: By modeling and analyzing porous alumina (PA), a method to modulate the colors of PA templates is proposed, which is based on the preparation of PA templates and the atomic layer deposition (ALD) technique. Referring to the experimentally prepared PA samples, theoretical simulations are carried out for a series of PA templates with the same hole-diameter and hole-interval, but with different hole-depths. The relationship between the modulated colors and the hole-depths are thus disclosed. By controlling the time of anodization in oxalic acidsolution, two PA samples with different hole-depths (296 nm and 373 nm) were prepared, both with an average hole-diameter of 40 nm and an average hole-interval of 100 nm, respectively. ALD processing is then applied to deposit a layer of Fe2O3 film with total thickness of 16.8 nm on these samples. It was experimentally observed that the processed PA samples show different colors which change with hole-depths. The experimental results are in good agreement with the theoretical simulations, which proves the feasibility of color modulation with this method.
Normal and reversed phase thin-layer chromatography of new 16,17-secoestrone derivatives
Journal of the Serbian Chemical Society , 2003,
Abstract: The retention behaviour and separation ability of a series of new 16,17-secoestrone derivatives has been studied on silica gel, alumina and C-18 silica gel layers with non-aqueous and aqueous-organic mobile phases. The retention behavour and separation ability are discussed in terms of the nature of the solute, eluent and stationary phase.
Production of γ-Al2O3 from Kaolin  [PDF]
Seyed Ali Hosseini, Aligholi Niaei, Dariush Salari
Open Journal of Physical Chemistry (OJPC) , 2011, DOI: 10.4236/ojpc.2011.12004
Abstract: The paper reports a process for synthesis of γ-alumina from kaolin. Kaolin was transformed to meta-kaolin by calcination at 800oC for 2h. γ-alumina powder was synthesized through extracting alumina from meta- kaolin via H2SO4 and meta-kaolin reactions and consequently precipitation in ethanol, which led to form the aluminum sulfate. The precipitated aluminum sulfate was dried and calcined at 900 oC for 2h, which resulted the formation of γ-alumina. The structure of γ-alumina was confirmed by XRD and FTIR and the mean particles size of γ-alumina was determined by SEM to be 0.5 - 0.9 µm. The study revealed the kaolin could be promising material for preparation of γ-alumina.
Effect of the Preparation Method on Co/Al2O3 Catalyst Applied to Ethanol Steam Reforming Reaction Production of Hydrogen  [PDF]
Silmara Rodrigues Garcia, José Mansur Assaf
Modern Research in Catalysis (MRC) , 2012, DOI: 10.4236/mrc.2012.13007
Abstract: Alumina supported cobalt catalysts were prepared, characterized and applied in ethanol steam reforming for hydrogen production. The support and the supported catalysts were prepared, respectively, by the solvothermal and precipitation, impregnation and deposition-precipitation methods. The cobalt was added by impregnation and deposition-precipitation in the Al2O3 supports using a Co(NO3)2·6H2O solution. The solids were characterized, Temperature-Programmed Re-duction with H2 (RTP-H2), X-Ray Diffraction (DRX), BET Nitrogen Adsorption and Temperature Programmed Oxida-tion (TPO). The results indicated that the preparation method and the treatment conditions of samples were appropriate for obtaining the wanted compounds. Co3O4 phase was verified for all catalysts through analyses of DRX and RTP-H2 results. Catalytic tests were performed by varying the temperature from 450?C to 600?C, with water: ethanol molar ratio of 3:1. The ethanol conversion was superior of 99%, with greater hydrogen yield at 600℃. The lower carbon deposition was observed in catalysts prepared with solvothermal/deposition-precipitation methods at 450℃.
Mineralogy of Iron Ores of Different Alumina Levels from Singhbhum Belt and Their Implication on Sintering Process  [PDF]
Moni Sinha, Sri Harsha Nistala, Sanjay Chandra, Tilak Raj Mankhand
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2015, DOI: 10.4236/jmmce.2015.33021
Abstract: To increase the life of the mines, ores of lower quality are blended with the higher quality ores. In general, the blending of ores at mines site is controlled by the chemical composition of the ores by controlling the Al2O3 and SiO2 levels on the lowest side possible. However, if there is a change in mineralogy, like an increase in hydrous phase the composition may still be the same, but this difference may affect the sinterability and sinter quality. The mineralogical investigation of iron ores and their chemistry are required to avoid the increase in deleterious elements during sintering. By the know-how of the behavior of individual iron ores in terms of their sinterability, in advance, the quality of the iron ores blend can be optimized to produce quality sinter and productivity. Characterisation studies conducted on iron ores of Singhbhum Orissa belt revealed that hematite, goethite, clay, gibbsite and quartz occur in all the iron ore samples but in variable proportions. Traces of alumina, present as solid solution in the iron oxide minerals, has also contributed Al2O3 to the ores.
Page 1 /4680
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.