Search results for "Manga"

Manganese iron oxide superparamagnetic powder by mechanochemical processing. Nanoparticles functionalization and dispersion in a nanofluid

2012

Manganese ferrite nanoparticles were synthesized using a High-Energy Ball-Milling mechanochemical method. After 1 h of milling, the process produces a material consisting of single crystalline domain nanoparticles having a diameter of about 8 nm. Chemical properties of the synthesized powders allow an easy functionalization with citric acid. Both as-obtained and functionalized samples show superparamagnetic behaviour at room temperature, and the functionalized powder is stably dispersible in aqueous media at physiological pH. The average hydrodynamic diameter is equal to similar to 60 nm. Nanoparticles obtained by the reported High-Energy Ball-Milling method can be synthesized with high yie…

Domain wall transformations and hopping in La0.7Sr0.3MnO3nanostructures imaged with high resolution x-ray magnetic microscopy

2014

We investigate the effect of electric current pulse injection on domain walls in La(0.7)Sr(0.3)MnO(3) (LSMO) half-ring nanostructures by high resolution x-ray magnetic microscopy at room temperature. Due to the easily accessible Curie temperature of LSMO, we can employ reasonable current densities to induce the Joule heating necessary to observe effects such as hopping of the domain walls between different pinning sites and nucleation/annihilation events. Such effects are the dominant features close to the Curie temperature, while spin torque is found to play a small role close to room temperature. We are also able to observe thermally activated domain wall transformations and we find that,…

Mesoporous Silica-Confined Manganese Oxide Nanoparticles as Highly Efficient Catalysts for the Low-Temperature Elimination of Formaldehyde

2013

Inside Back Cover: Mesoporous Silica-Confined Manganese Oxide Nanoparticles as Highly Efficient Catalysts for the Low-Temperature Elimination of Form…

2014

Effects of electrolyte doping on electrodeposited nanostructured manganese oxide and chromium oxide

2020

Abstract Electrolyte additions are used to control the functionality of a nanostructured oxide. Dopant ions affect the size and shape of deposit crystallites and modify the host structure. Such ions can be incorporated into the deposit or form a separate oxide phase. The manganese dioxide family of polymorphs with ion-molecular sieve properties represents the additional possibilities of “template” effects of dopant ions on the phase composition, heterovalent substitution in the cationic sublattice, changes in morphology and alteration of nanocrystallite size during electrocrystallisation. The effects of electrolyte doping in electrodeposited, non-stoichiometric manganese dioxide (NH4+, Li+ …

Structure and Phase Changes in Natural and Synthetic Magnesium Aluminum Spinel

2015

Natural spinel crystals from Ural and Pamir deposits and synthetic magnesium aluminium spinel single crystals with different stoichiometry (MgO.nAl2O3 ) grown by Verneuil method were used. The photoluminescence (PL), its excitation (PLE) and optical absorption of stoichiometric and nonstoichiometric magnesium aluminium spinel crystals containing the chromium and manganese ions and defects produced by fast neutron irradiation( fluence up to 1020cm-2, E>0.1 MeV) are investigated. The broadening of R- and N-lines takes place in synthetic stoichiometric spinel. Structure of synthetic nonstoichiometric spinels (n>1) has to be more disordered, since in addition to the site exchange …

Mapping Ash CaCO3, pH, and Extractable Elements Using Principal Component Analysis

2017

Abstract Ash cover in fire-affected areas is an important factor in the reduction of soil erosion and increased availability of soil nutrients. Thus it is important to understand the spatial distribution of ash and its capacity for soil protection and to provide nutrients to the underlying soil. In this work, we aimed to map ash CaCO3, pH, and select extractable elements using a principal component analysis (PCA). Four days after a medium to severe wildfire, we established a grid in a 9 ×27 m area on a west facing slope and took ash samples every 3 m for a total of 40 sampling points. The PCA carried out retained five different factors. Factor 1 had high positive loadings for ash with elect…

Microanalytical characterization of decorations in handmade ancient floor tiles using inductively coupled plasma optical emission spectrometry (ICP-O…

2013

In this study a total of 114 glazed decorations of 42 ceramic floor tiles, manufactured in Sicily fromthe 16th to 19 the 21th AD, were investigated. The micro sampling method, proposed by us, using a cotton swab soaked in hydrofluoric acid, includes advantages of high sensitivity, high selectivity, simplicity, speed, not expensive and can be considered non-destructive because the point of sampling remains invisible to the human eye. ICP-OES technique was used in this study. Twenty-four elements (Al, As, B, Be, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, Pb, Sb, Se, Si, Sn, Ti, V and Zn) were determined in each colored enamel. Enameled decorations in Sicilian tiles were varied in tones an…

Presentation, Calibration and First Experiments Using a New Thermobalance for Experiments in Sulfur Vapor Atmospheres

2004

Electrochemical Analysis of Catalytic and Oxygen Interfacial Transfer Effects on MnO2 Deposited on Gold Electrodes

2018

[EN] A theoretical model for obtaining thermochemical and kinetic information on oxygen interfacial transfer in metal oxides deposited on gold electrodes, based in the voltammetry of immobilized particle methodology, is presented. It is applied to MnO2 microparticulate deposits on gold in contact with aqueous NaOH solution using the voltammetric signals for the oxidation of gold to gold oxide monolayer and its subsequent desorptive reduction. Assuming reversibility, voltammetric peak potentials permit to estimate a variation of Gibbs free energy of interfacial oxygen transfer of -32 +/- 3 kj mol(-1). Analysis of peak current data based on the Sharp-Hancock formalism of solid-state kinetics …