High Pressure And High Magnetic Field Studies Of The Electronic Transport Properties Of The Antiferromagnet Eu3ir4sn13

In this work we report the effects of hydrostatic pressure and magnetic field on the electronic transport properties of the antiferromagnetic compound Eu(3)Ir(4)Sni(3) (T-N similar to 10 K). Single crystals of Eu3Ir4Sn13 were synthesized using the Sn self-flux technique. DC electrical resistivity measurements as a function of temperature were performed by means of the four-probe technique. The high-temperature anomaly at T* similar to 57 K attributed to a structural distortion of the Sn1Sn2(12) cages in Eu3Ir4Sn13 is rapidly decreased to lower temperatures at a rate dT*/dP = 2 K/kbar, while the antiferromagnetic transition due to the Eu2+ ions is only weakly affected. Our data do not indicate any magnetoelastic effect associated with the structural instability at T*. Furthermore, the suppression of the lattice distortion by application of external pressure is not accompanied by the emergence of superconductivity, possibly due to strong magnetic correlations between the Eu2+ localized magnetic moments.59

New sol-gel-derived magnetic bioactive glass-ceramics containing superparamagnetic hematite nanocrystals for hyperthermia application

Although the three main phases of iron oxide – hematite, maghemite, and magnetite – exhibit superparamagnetic properties at the nanoscale, only maghemite and magnetite phases have been explored in magnetic bioactive glass-ceramics aimed at applications in cancer treatment by hyperthermia. In this work, it is reported for the first time the superparamagnetic properties of hematite nanocrystals grown in a 58S bioactive glass matrix derived from sol-gel synthesis. The glass-ceramics are based on the (100-x)(58SiO2-33CaO-9P2O5)-xFe2O3 system (x = 10, 20 and 30 wt%). A thermal treatment leads to the growth of hematite (α-Fe2O3) nanocrystals, conferring superparamagnetic properties to the glass-ceramics, which is enough to produce heat under an external alternating magnetic field. Besides, the crystallization does not inhibit materials bioactivity, evidenced by the formation of calcium phosphate onto the glass-ceramic surface upon soaking in simulated body fluid. Moreover, their cytotoxicity is similar to other magnetic bioactive glass-ceramics reported in the literature. Finally, these results suggest that hematite nanocrystals' superparamagnetic properties may be explored in multifunctional glass-ceramics applied in bone cancer treatment by hyperthermia allied to bone regeneration

High pressure and high magnetic field studies of the electronic transport properties of the antiferromagnet Eu3ir4sn13

In this work we report the effects of hydrostatic pressure and magnetic field on the electronic transport properties of the antiferromagnetic compound Eu(3)Ir(4)Sni(3) (T-N similar to 10 K). Single crystals of Eu3Ir4Sn13 were synthesized using the Sn self-flux technique. DC electrical resistivity measurements as a function of temperature were performed by means of the four-probe technique. The high-temperature anomaly at T* similar to 57 K attributed to a structural distortion of the Sn1Sn2(12) cages in Eu3Ir4Sn13 is rapidly decreased to lower temperatures at a rate dT*/dP = 2 K/kbar, while the antiferromagnetic transition due to the Eu2+ ions is only weakly affected. Our data do not indicate any magnetoelastic effect associated with the structural instability at T*. Furthermore, the suppression of the lattice distortion by application of external pressure is not accompanied by the emergence of superconductivity, possibly due to strong magnetic correlations between the Eu2+ localized magnetic moments592International Conference on Strongly Correlated Electron Systems (SCES)2014-07FrançaUniversité Grenoble Alpe

Avaliação do tratamento de efluente da extração do óleo de dendê e potencial de produção de biogás.

O óleo de palma ou dendê é o óleo comestível mais consumido mundialmente, sendo o dendê a oleaginosa que apresenta a maior produtividade por área. Os resíduos e efluentes gerados durante o processo produtivo do óleo vêm sendo utilizados como bioinsumos e biocombustíveis, a partir de diversos métodos físicos, químicos e biológicos de aproveitamento destes coprodutos. O presente estudo tem como objetivo avaliar o tratamento do efluente da extração do óleo de dendê (POME), visando a diminuição da carga orgânica e o potencial de produção de biogás, a partir do processo de digestão anaeróbia. Foram avaliados diferentes volumes de inóculo (30, 40 e 50%), a fim de determinar o volume ideal para a redução da carga orgânica do efluente e produção de biogás. Os experimentos foram conduzidos em 10 reatores anaeróbios de bancada, acoplados a manômetros para verificar a pressão interna exercida pelo biogás gerado. Foi utilizado o volume de 100 mL para as misturas de efluente com inóculo, ajustado para pH igual a 7, durante 10 dias de operação, sob temperatura de 35±2°C. Os resultados sugerem que o POME apresenta elevado potencial para a produção de biogás. O tratamento que aplicou 30% de inóculo gerou o volume de 338 mL com concentração de 65% de gás metano, além de reduzir a DQO em 47,3%, indicando assim uma diminuição significativa na carga orgânica do efluente. Adicionalmente, o POME após o processo de tratamento pode ser utilizado como biofertilizante através de fertirrigação para o cultivo de dendê, agregando valor a esta cadeia produtiva agroindustrial

Conduction electron spin resonance in AlB2

ABSTRACT: This work reports on electron spin resonance experiments in oriented single crystals of the hexagonal AlB2 diboride compound (P6/mmm, D16h structure) which display conduction electron spin resonance. The X-band electron spin resonance spectra showed a metallic Dysonian resonance with g-value and intensity independent of temperature. The thermal broadening of the anisotropic electron spin resonance linewidth 1H tracks the T-dependence of the electrical resistivity below T ' 100 K. These results confirm the observation of a conduction electron spin resonance in AlB2 and are discussed in comparison with other boride compounds. Based on our main findings for AlB2 and the calculated electronic structure of similar layered honeycomb-like structures, we conclude that any array of covalent B–B layers potentially results in a conduction electron spin resonance signal. This observation may shed new light on the nature of the non-trivial conduction electron spin resonance-like signals of complex f-electron systems such as β-YbAlB4. Keywords: AlB2, Conduction electron, Dysonian resonance, Spin resonance