Resumo Os autores investigaram as respostas elétricas de três diferentes espessuras de cerâmica de 0,5ZrO2-0,5TiO2 com adição de LiClO4. Os sensores foram obtidos seguindo a rota de processamento tradicional e a escolha por um estudo preliminar na variação na espessura deve-se ao fato de que a distância entre as placas paralelas influi na capacitância que é inversamente proporcional a distância entre as placas, sendo que, para criar o efeito capacitivo, as superfícies planas superior e inferior das pastilhas foram revestidas com fita adesiva de carbono, sendo esta escolha da fita uma forma inédita de montagem. A análise de difração de raios-X mostrou a presença de zircônia monoclínica, titânia rutilo e de uma terceira fase cristalina oriunda de uma reação entre o Li+ do perclorato de lítio e a titânia, formando uma nova fase, o titanato de lítio. O sensor com 2 mm de espessura apresenta potencial para uso como sensor de umidade relativa do ar. 0,5ZrO20,5TiO2 05ZrO205TiO2 ZrOTiO 0,5ZrO2 0,5TiO2 0 5ZrO2 5TiO2 ZrO TiO 0,5ZrO2-0,5TiO LiClO4 LiClO devese deve se capacitivo carbono montagem raiosX raios X monoclínica Li ar 5ZrO20 0,5ZrO20,5TiO 05ZrO205TiO 05ZrO2 0,5ZrO 05TiO2 0,5TiO 5ZrO 5TiO 05ZrO 05TiO

Abstract The authors investigated the electrical responses of three different thicknesses of ceramic 0.5ZrO2-0,5TiO2 with addition of LiClO4. The sensors were obtained following the traditional processing route and the choice for a preliminary study in variation in thickness is due to the fact that a distance between parallel plates influences the capacitance that is inversely proportional to the distance between as plates, being that, to create the capacitive effect, as flat surfaces above and below the plates were coated with carbon adhesive tape, being this choice of tape an unprecedented form of assembly. A X-ray diffraction analysis showed a presence of zirconia (monoclinic), titanium (rutile), and a third crystalline phase derived from a reaction between the Li+ of lithium perchlorate and a titanium, forming a new phase, the Lithium titanate. The 2 mm thick sensor has potential for use as a relative humidity sensor. 0.5ZrO20,5TiO2 05ZrO205TiO2 ZrOTiO 0.5ZrO2 0,5TiO2 0 5ZrO2 5TiO2 ZrO TiO 0.5ZrO2-0,5TiO LiClO4 LiClO effect assembly Xray X ray monoclinic, monoclinic , (monoclinic) rutile, rutile (rutile) Li titanate 5ZrO20 0.5ZrO20,5TiO 05ZrO205TiO 05ZrO2 0.5ZrO 05TiO2 0,5TiO 5ZrO 5TiO (monoclinic (rutile 05ZrO 05TiO

Abstract Li7-xLa3Zr2-xO12-Tax (x =0, 0.1, 0.2, 0.3) nanostructured powders were successfully synthesized using an innovative wet chemical route via spray pyrolysis technique at 800 °C for 10 seconds, followed by post heat treatment at 800 °C for 30 minutes in a muffle furnace. X-ray diffraction (XRD) analysis confirmed that Ta-doping increased the cubic phase up to 99%. Scanning Electron Microscopy (SEM) showed spherical particles with sizes ranging from slightly below 200 nm to 3 µm. The powders were then pressed at 50 MPa and sintered at 850 °C for 7 minutes using Spark Plasma Sintering, followed by post heat-treatment at 900 °C for 2 hours in a muffle furnace. XRD indicated the majority predominance of the garnet cubic phase, and SEM images showed coalescence and longitudinal growth of the particles, forming layers inside the samples. This study reports a fast synthesis and sintering method to obtain cubic garnet crystalline structure in contrast to conventional methods that are widely used and published in the literature, which require longer parameters in the synthesis stages (~24 hours) and sintering stages (over 12 hours). Li7xLa3Zr2xO12Tax LixLaZrxOTax Li7 xLa3Zr2 xO12 Tax Li xLa Zr xO x 0 =0 01 1 0.1 02 0.2 0.3 03 80 C seconds furnace Xray X ray (XRD Tadoping Ta doping 99 99% (SEM 20 µm 5 85 Sintering heattreatment 90 samples literature ~24 24 (~2 over hours. . xLaZr xLa3Zr xO1 = 0. 8 9 ~2 (~ ~ (

Abstract The thermal conductivity of engobed building ceramics was studied as a function of their microstructure. The following thermal conductivity coefficients of the samples were determined: clinker bricks with 5% water absorption - 1.04 W/(m·K) and facing bricks (ordinary) with 12% water absorption - 0.48 W/(m·K) (ignoring the voids in the samples). A comparison of the thermal conductivity of brick samples of uniform thickness without engobe and with engobe showed that the latter had a slight increase in thermal conductivity of 0.3% due to forming a denser outer layer on its surface with 2.0-0.3% water absorption. However, as the engobe coating is applied as an additional layer on the top of the ceramic bricks and the product has a greater thickness, the heat flow through the engobed bricks is 0.1-0.2 % lower. The results can be applied to technologies for achieving energy-efficient decorative and protective coatings for building ceramics. microstructure determined 5 104 1 04 1.0 W/m·K WmK W/ m·K W m K W/(m·K ordinary (ordinary 12 048 0 48 0.4 ignoring samples. . samples) 03 3 0.3 2.00.3% 2003 2.0 2 2.0-0.3 However 0.10.2 0102 0.1 0.2 0.1-0. lower energyefficient energy efficient 10 1. mK 4 0. 00 2.00.3 200 20 2. 2.0-0. 0.10. 010 01 02 0.1-0 2.00. 2.0-0 0.10 0.1- 2.00 2.0-

ABSTRACT The rice husk was chemically treated with acetic acid and calcined at 600 °C, in an uncontrolled atmosphere to obtain the ash (RHA), and in an oxygen-limited atmosphere to produce the biochar (BC). The influence of the thermal treatment on the adsorbent properties for removing cationic (methylene blue) and anionic (methyl orange) dyes was investigated. Both materials showed amorphous structures rich in silica, with acicular morphology and a high roughness. High surface areas (157.2 and 215.5 m²g-1) and pH at the point of zero charge close to neutrality (6.73 and 6.58) for RHA and BC were found, respectively. The anionic dye was adsorbed only by BC due to its contribution to the π- π stacking interaction between the C=C bonds of the adsorbent and the benzene rings of the dye. In contrast, the cationic dye was adsorbed by electrostatic interaction between the Si-O-Si and Si-OH groups of the adsorbents, with the positive charge of the dye. All adsorption isotherms adjusted better to the SIPS model, suggesting adsorption in homogeneous and heterogeneous sites. The observed results suggest good adsorption capacities and the interactions between surface groups on the adsorbents and functional groups of the contaminants are the most important mechanism in the adsorption of dyes of different ionic natures on surfaces derived from rice husk. 60 C °C RHA, , (RHA) oxygenlimited oxygen limited BC. . (BC) methylene blue methyl orange investigated silica roughness 157.2 1572 157 2 (157. 2155 215 5 215. m²g1 mg m²g 1 m g m²g-1 6.73 673 6 73 (6.7 6.58 658 58 found respectively CC contrast SiOSi Si O SiOH OH model sites (RHA (BC 157. 15 (157 21 m²g- 6.7 67 7 (6. 6.5 65 (15 6. (6 (1 (