Interplay between the magnetic anisotropy contributions of Cobalt nanowires

We report on the magnetic properties and the crystallographic structure of the cobalt nanowire arrays as a function of their nanoscale dimensions. X-ray diffraction measurements show the appearance of an in-plane HCP-Co phase for nanowires with 50 nm diameter, suggesting a partial reorientation of the magnetocrystalline anisotropy axis along the membrane plane with increasing pore diameter. No significant changes in the magnetic behavior of the nanowire system are observed with decreasing temperature, indicating that the effective magnetoelastic anisotropy does not play a dominant role in the remagnetization processes of individual nanowires. An enhancement of the total magnetic anisotropy is found at room temperature with a decreasing nanowire diameter-to-length ratio (d/L), a result that is quantitatively analyzed on the basis of a simplified shape anisotropy model.Comment: 8 pages, 4 figure

Use of Gas Emulsion in Blasting Project for Clearing in a Copper Mine in Southern Peru

The gasifiable emulsion is a technological and productive response to the need to reduce operating costs in the mining project, among the improvements with respect to ANFO are a higher detonation velocity (VOD), better fragmentation and reduction of nitrous fumes. In the test mining operation, a commercial explosive mixture called "Q "73 (70% emulsion and 30% ANFO) is used, where the ANFO is composed of 97% ammonium nitrate and 3% diesel, and the explosive mixture "Q "82 (80% emulsion and 20% ANFO) is also used, 7 blasting processes were carried out with a diameter of 12.25 in. in a waste area, the most characteristic rocks found in the blasting project in the copper mine in southern Peru are Toba Cristal (TC), Andesite Basaltic Propylitic (BA-PRO), Andesite Basaltic Argillic (BA-ARG). The results obtained show a reduction of the Power Factor by 1.32%, with respect to the commercial mixtures "Q "73 and "Q "82 an optimum increase in the detonation velocity of 9.92% and 0.59% was obtained, also the high-resolution images of the fumes after blasting indicate a low presence of orange fumes taking a great relevance in the mining sector on a large scale, achieving better results in the blasting phase

Competição de cultivares de milho no Território Federal de Roraima.

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Angle-resolved and core-level photoemission study of interfacing the topological insulator Bi1.5Sb0.5Te1.7Se1.3 with Ag, Nb and Fe

Interfaces between a bulk-insulating topological insulator (TI) and metallic adatoms have been studied using high-resolution, angle-resolved and core-level photoemission. Fe, Nb and Ag were evaporated onto Bi1.5Sb0.5Te1.7Se1.3 (BSTS) surfaces both at room temperature and 38K. The coverage- and temperature-dependence of the adsorption and interfacial formation process have been investigated, highlighting the effects of the overlayer growth on the occupied electronic structure of the TI. For all coverages at room temperature and for those equivalent to less than 0.1 monolayer at low temperature all three metals lead to a downward shift of the TI's bands with respect to the Fermi level. At room temperature Ag appears to intercalate efficiently into the van der Waals gap of BSTS, accompanied by low-level substitution of the Te/Se atoms of the termination layer of the crystal. This Te/Se substitution with silver increases significantly for low temperature adsorption, and can even dominate the electrostatic environment of the Bi/Sb atoms in the BSTS near-surface region. On the other hand, Fe and Nb evaporants remain close to the termination layer of the crystal. On room temperature deposition, they initially substitute isoelectronically for Bi as a function of coverage, before substituting for Te/Se atoms. For low temperature deposition, Fe and Nb are too immobile for substitution processes and show a behaviour consistent with clustering on the surface. For both Ag and Fe/Nb, these differing adsorption pathways leads to the qualitatively similar and remarkable behavior for low temperature deposition that the chemical potential first moves upward (n-type dopant behavior) and then downward (p-type behavior) on increasing coverage.Comment: 10 pages, 4 figures. In our Phys. Rev. B manuscript an error was made in formulating the last sentence of the abstract that, unfortunately, was missed in the page proofs. Version 2 on arxiv has the correct formulation of this sentenc

Competição de cultivares de milho no Pará.

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Avaliação de cultivares de milho na Transamazônica - Pará.

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