The Effect of Nano-SiO2 on the Structural, Electrical and Magnetic Properties of SiO2-LiFe5O8 Glass–ceramics Prepared by Sol Gel Auto-combustion Processing

The glass–ceramic with the composition x(LiFe5O8)/(100 – x) SiO2 (x = 20, 30, 40, 50, 100 wt. % ) were prepared by sol gel auto-combustion method. The influence of the SiO2 ratio in the glass-ceramics strucure prepared was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Crystalline phases (LiFe5O8, SiO2, Fe2O3) were observed by X-ray powder diffraction in the glasses annealed at 800°C for 2h. The crystallite size was found to increase from 27.29 nm (x = 20%) to 91.48 nm(x = 100 %). The microstructure of the formed powders was SiO2 ratio dependent. Increasing the SiO2 ratio was found to inhibit the grain growth of the formed ferrite. The electrical conductivity of glass-ceramics samples were raised with increasing the concentration of SiO2 ratio as the result of increasing the hopping of electrons between Fe2+ and Fe3+ ions. The magnetic characteristics of the prepared glass ceramics were performed using a vibrating sample magnetometer in function of the magnetic field. The samples heat -treated at 800°C for 2h present a ferrimagnetic behavior. Alongside, the formed crystalline silicate lithium ferrite had good magnetic properties. High saturation magnetization (51.9 emu/g) was attained the formed ferrite sample of x = 100 % ratio annealed at 800°C for 2h

The Effect of Nano-SiO2 on the Structural, Electrical and Magnetic Properties of SiO2-LiFe5O8 Glass–ceramics Prepared by Sol Gel Auto-combustion Processing

The glass–ceramic with the composition x(LiFe5O8)/(100 – x) SiO2 (x = 20, 30, 40, 50, 100 wt. % ) were prepared by sol gel auto-combustion method. The influence of the SiO2 ratio in the glass-ceramics strucure prepared was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Crystalline phases (LiFe5O8, SiO2, Fe2O3) were observed by X-ray powder diffraction in the glasses annealed at 800°C for 2h. The crystallite size was found to increase from 27.29 nm (x = 20%) to 91.48 nm(x = 100 %). The microstructure of the formed powders was SiO2 ratio dependent. Increasing the SiO2 ratio was found to inhibit the grain growth of the formed ferrite. The electrical conductivity of glass-ceramics samples were raised with increasing the concentration of SiO2 ratio as the result of increasing the hopping of electrons between Fe2+ and Fe3+ ions. The magnetic characteristics of the prepared glass ceramics were performed using a vibrating sample magnetometer in function of the magnetic field. The samples heat -treated at 800°C for 2h present a ferrimagnetic behavior. Alongside, the formed crystalline silicate lithium ferrite had good magnetic properties. High saturation magnetization (51.9 emu/g) was attained the formed ferrite sample of x = 100 % ratio annealed at 800°C for 2h

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Compatibilidade entre tratamento de sementes de amendoim com fungicidas, sobrevivência de Rhizobium e nodulação Compatibility between peanut seed preservation with fungicides, survival of rhizobia and nodulation

Conduziu-se um experimento para testar a compatibilidade dos fungicidas captã, PCNB e tirã com a inoculação de sementes de amendoim, cujo tratamento se efetuou simultaneamente com a inoculação ou dez dias antes desta. No momento da inoculação e quatro horas após, fez-se uma contagem de Rhizobium nas sementes, pelo método da diluição e inoculação de gotas em placas, mantendo-se um controle sem aplicação de fungicida. Para se estudar o efeito dos tratamentos na nodulação e fixação, plantaram-se as sementes em solo esterilizado, avaliando-se a nodulação e o teor de ureídeos nas folhas. Somente o captã aplicado simultaneamente à inoculação foi prejudicial à sobrevivência bacteriana nas sementes. De maneira geral, a aplicação dos fungicidas simultaneamente à inoculação mostrou-se prejudicial em relação à antecipada.<br>An experiment was carried out to test the compatibility between peanut seed treated with the fungicides captan, PCNB and thiram with rhizobia inoculation. The application of the fungicides was done either simultaneously or ten days before the inoculation of the seeds. A control, without inoculation, was included. Countings of rhizobia on the seed were made immediately after inoculation and four hours after, by dilution and drop plating technique. In order to study the effect of treatments on nodulation and nitrogen fixation, treated and untreated seeds were planted in gamma irradiated soil and nodulation and leaf ureid content were later evaluated. It was observed that only captan applied to the seed simultaneously with inoculation was significantly deleterious to survival of the rhizobia. In general the application of the fungicide ten days before inoculation caused no significant harmfull effect to survival of rhizobia on the seed