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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 100 for “"Iron oxides."”.
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Application of Mixed Iron Oxides in Subsurface Remediation Technologies
… removal of Cr(VI ), Cd(II) and As(V) by mixed iron oxide nanoparticles depends on pH, temperature, contact time, solid/liquid ratio and initial concentration of heavy metals. The results showed that Cr(VI) adsorption on mixed maghemite-magnetite was dependent on solution pH between 3 and 6. …
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Ultrafast light-induced dynamics of spins and lattice in iron oxides
Contains fulltext : 75624.pdf (Publisher’s version ) (Open Access)
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The effect of surface modification on the crystal growth of iron oxides
… modifiers were used to alter the formation of iron oxides from ferrous hydroxide precipitates. Multifunctional carboxylic acids were found to have a strong influence on morphology of FeOOH. Dicarboxylic acids, containing two and seven carbons, changed the characteristics of α-FeOOH. These …
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Determining optimum imaging parameters for SWIFT: application to superparamagnetic iron oxides and magnetized objects.
… and applied to imaging of superparamagnetic iron oxides. Susceptibility artifacts distort images around metal objects. In SWIFT images the susceptibility artifacts manifest as signal voids surrounded by pileup artifacts. This work develops predictive equations for the pileup artifacts around …
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Mn(II) oxidation by HOCl in the presence of iron oxides: a catalyzing effect
… however, the role of ferric hydroxide/oxides (Fe(OH)₃<sub>(s)</sub>) in catalyzing the oxidation of Mn(II) by oxidants such as free chlorine (HOCI) is one specific aspect of manganese removal via oxidation that requires further investigation. Data collected in this study indicate that …
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Decomposition of hydrogen peroxide and organic compounds in the presence of iron and iron oxides
… either Fe(II) (the Fenton reaction), Fe(1), or iron oxide. This dissertation investigated the factors that influence the decomposition rates of H202 and organic compounds, as well as the generation rate of -OH (VoH), in the presence of dissolved Fe(IH) and iron oxide. The Fe(III)-initiated chain …
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An investigation of the reactions of carbon dioxide, carbon monoxide, methane, hydrogen, and water over iron, iron carbides, and iron oxides
Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemical Engineering.
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Arsenic Adsorption on Iron Oxides in the Presence of Soluble Organic Carbon and the Influence of Arsenic on Radish and Lettuce Development
… and maturing plants in arsenic enriched environments. Such information is however very important to many vegetable growers in areas of subsistent agricultural like Bangladesh or home-gardeners in closer proximity of As sources such as metal smelters. Accordingly we conducted research …
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Assessment of Arsenic Mobility Using Sequential Extraction and Microscopic Methods
… total arsenic in sediments is associated with iron oxides, and an additional phosphate extraction showed that the majority (80%) of arsenic associated with the oxides is adsorbed. Imaging and analysis by scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) show the …
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Formation and Quantification of Corrosion Deposits in the Power Industry
… the presence of impurities, metals and metallic oxides in the secondary side of the steam generator units result in formation of deposits. This research deals with understanding the deposit formation and characterization of deposits by studying the samples collected from different units in …
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Propriedades de solos vermelhos do Estado da Paraíba
… to study the distribution of silica, alumina and iron oxides as a funtion of size. It is shown that iron oxides and amorphous silica are the main cementing agents and that geothite, hematite, prehematite and amorphous iron oxides are present as main components, as well as kaolinite in most of the …
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Trace Element Cycling during Iron(II)-activated Recrystallization of Iron(III) Oxide Minerals
Biogeochemical iron cycling initiates secondary abiotic reactions between aqueous Fe(II) and Fe(III) oxide minerals, which results in dynamic recrystallization via simultaneous Fe(II) oxidative adsorption and Fe(III) reductive dissolution. Fe(III) oxide minerals are abundant in soils, sediments, …
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The performance of potassium permanganate and hydrogen peroxide oxidation and/or alum coagulation in the removal of complexed FE(II) from drinking water
… between particulate, colloidal, and soluble iron species was achieved through the use of 0.2 urn filters and 100K ultrafilters. Results from oxidation and ultrafiltration studies indicated incomplete complexation of the Fe(II) by DOC in solution. Following the addition of either oxidant, …
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Iron oxide amended biosand filters for virus removal
… were performed to determine if the addition of iron oxides throughout biosand filter (BSF) media would increase virus removal due to adsorption. The proposed mechanism is electrostatic adsorption of negatively charged virion particles to positively charged iron oxides formed during the corrosion …
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Identification And Analysis Of Genes Involved In Anaerobic Nitrate-Dependent Iron Oxidation
… released into aquatic and terrestrial environments by mining, industrial processes, and municipal waste disposal practices is an area that deserves significant scientific, public health, and regulatory attention. Indirect microbial interaction offers one potential mechanism for …
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Development of new processes for ISRU (In Situ Resource Utilization) and ISFR (In Situ Fabrication and Repair) applications on Moon and Mars
… construction materials in Lunar and Martian environments is described. The mixtures to be reacted by SHS are prepared taking advantage of the composition of lunar and martian regoliths. Lunar regolith simulant JSC-1A, Martian regolith JSC-1A, and Mojave martian regolith simulant are considered. …
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Electrochemical Deactivation of Nitrate, Arsenate, and Trichloroethylene
… and trichloroethylene inactivation on zerovalent iron (ZVI), mixed-valent iron oxides, and boron doped diamond film electrode surfaces, respectively. Nitrate ( ) is a common co-contaminant at sites remediated using permeable reactive barriers (PRBs). Therefore, understanding nitrate reactions with …
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Infrared radiometric measurements of surface temperatures generated by friction of sliding iron-on-sapphire
… The sliding system consisted of an Armco iron pin, with a hemispherical end loaded against a rotating sapphire disk. A statistical study was made concerning the effect of environment, load, and velocity on temperature, wear, and coefficient of friction. The formation of iron oxides and its …
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Síntese e caracterização de nanopartículas de óxidos de ferro e sua mistura com resíduos da cana-de-açúcar (bagaço e palha) para emprego nos processos de adsorção e fotocatálise heterogênea
Iron oxide nanoparticles have gained great prominence over the years due to their numerous applications in different areas of knowledge. In addition, the microwave-mediated synthesis route has been widely used, mainly due to the shorter reaction time, lower material consumption and production of …
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Selective Reduction of Laterite Ore
… and rate of reduction of nickel, cobalt and iron oxides under different conditions, reduction mechanisms, and optimum conditions for selective reduction of nickel and cobalt oxides. Ore reduction with the size 53-200 μm and size < 53 μm was studied at 700-1000 ℃ in the CO-CO2 gas mixture …
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