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Crystallization kinetics parameters of a stoichiometric glass with the composition Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 were investigated by subjecting parallelepipedonal samples (3 × 3 × 1.5 mm) to heat treatment in a differential scanning calorimeter at different heating rates (3, 5, 8 and 10 °C/min). The data were analyzed using Ligero's and Kissinger's methods to determine the activation energy (E) of crystallization, which yielded, respectively, E = 415 ± 37 kJ/mol and 378 ± 19 kJ/mol. Ligero's method was also employed to calculate the Avrami coefficient (n), which was found to be n = 3.0. A second set of samples were heat-treated in a tubular furnace at temperatures above the glass transition temperature, T g , to induce crystallization. The X-ray diffraction analysis of these samples indicated the presence of LiGe 2 (PO 4 ) 3 which displays a NASICON-type structure. An analysis by optical microscopy revealed the presence of spheric crystals located primarily in the volume, in agreement with the crystallization mechanism predicted by the Avrami coefficient.

This paper proposes the glass-ceramics method for obtaining lithium ion (Li + ) solid electrolytes. This technique provides high chemical and microstructural homogeneity as well as low porosity. Glass samples were subjected to either single or double heat treatments, between 700 °C and 1000 °C, in order to obtain the glass-ceramics. Differential Scanning Calorimetry -DSC -results evidenced the possibility of fabricating these ceramics from glass in the system Li2O·Al2O3·TiO2·P2O5. Samples observed by Scanning Electron Microscopy -SEMshowed a finely grained microstructure which was homogeneously distributed and non-porous. X-ray Diffraction -XRD -patterns showed the formation of the high conducting phase LiTi2(PO4)3. A high ionic conductivity, in the order of 10 -3 S/cm at 1000 °C, was measured by Impedance Spectroscopy -IS. It suggests that the synthesis method used in this research is useful for fabricating lithium ion glass-ceramics and opens up a new alternative for manufacturing different electrical ceramics.

The present study is focused on the chemical and nano-mineralogical characterization of sludge from gold mine activities, in order to put forward diverse solution alternatives, where lack of knowledge has been found. The sample was collected from "La Estrella" mine of Suarez, located in Department of Cauca, south-west Colombia. The sludge micro-structure and chemical composition were analyzed using a high resolution transmission electron microscopy (HR-TEM) equipped with a dispersive X-ray detector (EDS). X-ray diffraction technique was employed to identify the mineralogical phases present in the sludge. Additional mineralogical characterization was done by using RAMAN spectroscopy. Main findings points to its potential to be used as a fertilizer, this is why, mine sludge contains macronutrients such as P, Ca and S, together with micronutrients like Cu. However, the presence of goethite could decrease the mobilization of nutrients to soils, thus additional alternatives, for instance, a mixture with humus or another material containing Humic Acids should be done, in order to minimizing its retention effect. Additionally, another possible uses to explore could be as construction and ceramic material or in the wastewater treatment for nutrient retention and organic material removal. Rutile (TiO nanoparticles) particles have been also detected, what could cause health concern due to its nanoparticle toxic character, mainly during gold extraction process.

Bovine mastitis is defined as inflammation of the udder caused mainly by bacterial pathogens and depending on the degree of inflammation it is classified as subclinical and clinical. Particularly in the subclinical form, there are no alterations in milk, udder or animal, but it does affect its components, impairing its use in the dairy industry, and leading to significant economic losses due to discard and decrease in production. Therefore, the detection of subclinical mastitis is based on field and laboratory tests. Currently, there are several methods, mostly based on the measurement of somatic cells present in milk because of the inflammatory process. In this paper, an approach is made on the different methods of detection of subclinical mastitis in milk from conventional or traditional to alternative methods with greater precision.

<p>In this work was obtained solid electrolytes of fully stabilized zircônia with doped of 10 and 12 mol% of <em>Re₂O₃</em> (mixed oxides rare earth), for use in oxygen sensors and or fuel cells. The specimens were prepared by uniaxial pressing and sintered using two heating schedules, <em>S1</em> and <em>S2</em>. Impedance diagrams show that the crystalline phases and the grain size change the electrical behavior of the ceramics. The sample with the best electrical performance was obtained with 10 mol% doped and was sintered with the curve S1. The value of the total conductivity of this sample was 2,85x10^-3 <span style="font-family: Symbol;">W</span>^-1.cm^-1 (taken at 600 ° C). When making a comparison between this values of conductivity with the reported in the literature is identified similarity with or traditional system zirconia-yttria the most widely used commercially as electrolyte oxygen sensors and fuel cells, confirming the potential use of the oxides mixed rare earth for these specific applications.</p>

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Solid electrolytes based on stabilized zirconia have been studied a long time ago in its cubic phase because of its electrical properties, which make them excellent candidates to be used in applications such as oxygen sensors and solid oxide fuel cells [1], [2]. Lambda sensor or oxygen sensor, as it is also known, is a device that measures the oxygen concentration of the gases that flow through the exhaust pipe. Physically, the lambda sensor has two electrodes. The outer which is exposed to the exhaust gases and the inner to the air (reference) [3]; these electrodes are made, generally, of porous platinum. The ceramic material, i.e., zirconium oxide, is placed in between the electrodes, so the oxygen ions can move from one electrode to another. As one of the electrodes is exposed to the reference gas, the voltage generated is a measure of the concentration of oxygen in the exhaust gases [4].