Effect of Ce3+ Ion on Structural and Hyperfine Interaction Studies of Co0.5Ni0.5Fe2−xCexO4 Ferrites: Useful for Permanent Magnet Applications

Abstract Nanoparticles of Co0.5Ni0.5Fe2−xCexO4 (where x = 0.0, 0.01, 0.015 and 0.02) ferrites are prepared by the modified solution combustion method using a mixture of fuels and are characterized to understand their structural, microstructural and magnetic properties. The X-ray diffraction is used to confirm the formation of a single-phase cubic spinel structure. The average crystallite sizes are calculated using the Scherrer formula and are found to be less than 50 nm. The microstructural features are obtained by the scanning electron microscopy, and the compositional analysis is done by using the energy-dispersive spectroscopy. The transmission electron microscopy (TEM) investigations show that the synthesized ferrites are made up of very fine spherical nanoparticles. The influence of a rare-earth element (Ce3+) on the magnetic properties of the samples was studied using the Mössbauer spectroscopy. The Mössbauer spectroscopy reveals the formation of broadened Zeeman lines and quadrupole-split lines and the presence of the Fe3+ charge state at B sites in the samples. The quadrupole splitting shows that the orientation of the magnetic hyperfine field with respect to the principle axes of the electric field gradient was random. The magnetic hyperfine field values indicate that the A sites have more A-O-B superexchange interactions than the B sites. The coexistence of magnetic sextet and a doublet component on the room-temperature spectra suggests superparamagnetic properties of the nanoparticles. The low-temperature (15 K) Mössbauer spectroscopy explores the paramagnetic relaxation in the nanoparticles. The area under the sextet refers to Fe3+ concentrations in the tetrahedral and octahedral sites of the ferrite. This study confirms that the Ce3+ substitution of Fe3+ only for octahedron sites causes the decrease in Fe-O-Fe arrangement. The effect of Ce3+ doping on the magnetic properties of Co0.5Ni0.5Fe2O4 is examined from the vibrating sample magnetometry (VSM) spectra. Saturation magnetization values are decreased initially and then increased, as result of Ce3+ doping. This can be explained by Neel’s two-sub-lattice model. Further, the value of coercivity is found to be increasing with increasing Ce3+ concentration. The obtained results of M-H loop with improved coercivity (from 851 to 1039 Oe) by Ce3+ doping of Co0.5Ni0.5Fe2O4 demonstrate the usefulness for permanent magnet applications

Estimating soil fertility status in physically degraded land using GIS and remote sensing techniques in Chamarajanagar district, Karnataka, India

Soil physical degradation is a major environmental problem throughout the world due to its negative impact on biomass and economic production. This study presented new ways of combining rapid soil analysis using GIS and remote sensing imagery to provide a precision mapping of soil physical condition indicators in the study area and producing fertility status using Geostatistical approach. Study has been carried out to map the areas with physical degradation using remotely sensed data from Indian Remote Sensing LISS III sensor. It was observed that the data enabled better delineation of small units of eroded areas. Satellite data have been used for qualitative assessment of areas, being subject to soil erosion. Soil erosion was found to be none or slight to very sever using visual interpretation of IRS data along with field survey method where soil erosion was found to be moderate to high using the RUSLE method. The eroded areas of degraded lands will be used as an input for planning reclamation and conservation programs in Chamarajanagar district of Karnataka. Soil compaction is a form of physical degradation resulting in densification and distortion of the soil where biological activity, porosity and permeability are reduced, strength is increased and soil structure partly destroyed. Compaction can reduce water infiltration capacity and increase erosion risk by accelerating run-off. The compaction process can be initiated by wheels, tracks, rollers or by the passage of animals. Some soils are naturally compacted, strongly cemented or have a thin topsoil layer on rock subsoil. Soils can vary from being sufficiently strong to resist all likely applied loads to being so weak that they are compacted by even light loads

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Not AvailableAn experiment was carried out on nutrient dynamics and biochemical changes during decomposition of leaf litter of six selected forest species grown on Alfisol in GKVK, University of Agricultural Sciences, Bangalore, during Apri1 2010 to April 2011. Chemical characteristics and decomposition patterns of six forest tree species, leaf litter viz., Simaruba glauca (Simaruba), Tectona grandis (Teak wood), Ailanttius maiabarica, (White bean), Aphanamyxis polystachya (Amoora), Sweitenia macrophylla (Mahagany) and mixed leaf litter (Accacia. Eucalyptus, Bamboo) were analysed. The content of cellulose, hemi cellulose, polyphenol and lignin varied among species recording higher values. Results of the decomposition study using litter bag revealed that residual litter mass declined exponentially with time in case of Simaruba, Teak, White bean, Amoora, Sweitenia and Mixed leaf litter. In terms of nutrient release N & P recorded maximum releaseNot Availabl

Discovery of syllabic percussion patterns in tabla solo recordings

We address the unexplored problem of percussion pattern/ndiscovery in Indian art music. Percussion in Indian art music uses onomatopoeic oral mnemonic syllables for the transmission of repertoire and technique. This is utilized for the/ntask of percussion pattern discovery from audio recordings./nFrom a parallel corpus of audio and expert curated scores/nfor 38 tabla solo recordings, we use the scores to build a/nset of most frequent syllabic patterns of different lengths./nFrom this set, we manually select a subset of musically representative query patterns. To discover these query patterns/nin an audio recording, we use syllable-level hidden Markov/nmodels (HMM) to automatically transcribe the recording/ninto a syllable sequence, in which we search for the query/npattern instances using a Rough Longest Common Subsequence (RLCS) approach. We show that the use of RLCS/nmakes the approach robust to errors in automatic transcrip-/ntion, significantly improving the pattern recall rate and F-/nmeasure. We further propose possible enhancements to improve the results.This work is partly supported by the European Research/nCouncil under the European Union’s Seventh Framework/nProgram, as a part of the CompMusic project (ERC grant/nagreement 267583

Discovery of syllabic percussion patterns in tabla solo recordings

We address the unexplored problem of percussion pattern/ndiscovery in Indian art music. Percussion in Indian art music uses onomatopoeic oral mnemonic syllables for the transmission of repertoire and technique. This is utilized for the/ntask of percussion pattern discovery from audio recordings./nFrom a parallel corpus of audio and expert curated scores/nfor 38 tabla solo recordings, we use the scores to build a/nset of most frequent syllabic patterns of different lengths./nFrom this set, we manually select a subset of musically representative query patterns. To discover these query patterns/nin an audio recording, we use syllable-level hidden Markov/nmodels (HMM) to automatically transcribe the recording/ninto a syllable sequence, in which we search for the query/npattern instances using a Rough Longest Common Subsequence (RLCS) approach. We show that the use of RLCS/nmakes the approach robust to errors in automatic transcrip-/ntion, significantly improving the pattern recall rate and F-/nmeasure. We further propose possible enhancements to improve the results.This work is partly supported by the European Research/nCouncil under the European Union’s Seventh Framework/nProgram, as a part of the CompMusic project (ERC grant/nagreement 267583

Mechanical property and microstructure development in alkali activated fly ash slag blends due to efflorescence

Efflorescence of alkali activated materials (AAMs) is caused by alkali leaching and precipitation of carbonated salts, which occurs concurrently with leaching and natural carbonation. Efflorescence is specifically driven by precursor and activator variability in AAMs vis-a-vis phase changes, microstructure, and mechanical properties are not well understood. To that end, this study analyses the effects of long-term (90 days) efflorescence on AAMs with eight varied calcium and activator contents and correlated with compressive and splitting tensile strengths. Microstructural features including N-A-S-H/C, N-A-S-H gel change are analysed using Fourier-transform infrared spectroscopy (FTIR), magic-angle spinning nuclear magnetic resonance (MAS-NMR) and thermogravimetric analysis (TGA). AAMs with 9 wt% Na2O and Ca/(Si + Al) ratio of 0.0 to 0.25 exhibit enhanced efflorescence and dealumination of Al[IV] in N-A-S-H/C,N-A-S-H gels, higher mobility of Na+ ions, and natural carbonation. AAMs with 5 wt% Na2O and Ca/(Si + Al) ratio of 0.0 to 0.25 exhibit lower efflorescence and higher stability, in contrast. Under efflorescence, the binder with 5 wt% Na2O and Ca/(Si + Al) ratio of 0.25 exhibited dealumination and carbonation, and the binders with 5 wt% Na2O and Ca/(Si + Al) of 0.0 to 0.10 showed less dealumination and higher concentration of Al[IV] in aluminosilicate gel, indicative of greater phase stability. This study highlights the criticality of calcium and activator doses in controlling the stability of phase composition and mechanical property, which is essential for the industrial application of AAMs