Repositório RCAAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

This study evaluated the ceramic tiling in three distinct aspects, impermeabilty to water, water vapor permeability and tensile adhsion strength. For this study, four boxes in concrete structural blocks were built, and each box received a ceramic tiling system. Box 1 reproduced the tradicional system, composed of concrete block, roughcast, plaster, adhsive mortar, tile and grout. In Box 2, the tile was applied in roughcast. In the Box 3 the tile was applied on a rigid waterproofing layer and Box 4 had the ceramic tiling applied directly on the concrete block. As conclusions of this study, all systems presented a good performance regarding the adhseion resistance to traction, with results above the minimum required by standard. The Box 4 presented the biggest adhrence resistance followed by Box 1, Box 2 and Box 3. No system proved effective for watertightness, all showed infiltration points. The system with less water loss was the Box 3, followed by boxes 1, 4 and 2. For testing permeability to water vapour, the boxes were subjected to water vapor during 6 hours, no moisture stain on the outside of the boxes has been verified, however, all registered a temperature increase in the external faces, this increase in temperature was greater the lower was the number of system layers, thus, Box 4 presented the highest mean temperature, followed by Box 2, Box 3 and Box 1. With the results presented in this study , it becomes evidente the need to develop improvements in the performance os the ceramic tiling system, making it na effective system as much as the adhesion, as the watertightness and permeability to water vapor.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Intraocular pressure (IOP) is checked using tonometry, which helps in the diagnosis of diseases that lead to hypotension or ocular hypertension. Being, uveitis and glaucoma, the main eye diseases that alter IOP and generate the need for an early diagnosis and treatment for more satisfactory results and patient comfort. It is known that this test is still little used in the routine of production animals, because, in the literature, there are few data on the subject. For a reliable diagnosis of diseases that cause changes in IOP, it is necessary to have knowledge of the normal values of this parameter and its physiological variations at different times of the day. The objective of the test was to analyze the IOP values during a period of 24 hours, obtaining data for the elaboration of the daily tension curve (CTD) and mini curve of the sheep species. In addition, compare the IOP with the cortisol levels of the studied species, in each hour during a period of one day, in order to correlate the data of these two variables. This study was carried out with the number of animals suitable for this proposal, being 12 Texel ewes, under minimal restraint and in their natural habitat, aiming at minimal external interference in the data presented. With this, it was possible to affirm that there is no statistically significant difference between the IOPs of the right eye (OD) and left eye (LE), considering the 24 measurements performed over 24 hours. However, in the values of the IOPs of both eyes, every hour, there was a statistically significant difference between different times of the day. Furthermore, the maximum and minimum IOP peaks during the 24 hours of the day followed the cortisol levels at the same times. In addition, these variables were correlated with the daily luminosity rate. After analyzing the data obtained, it was possible to determine the physiological CTD of Texel sheep, noting a positive feedback relationship between IOP and blood cortisol rates. Then, a mini daily tension curve was proposed, with IOP measurements at 04:00h (average IOP value), at 12:00h (maximum IOP peak) and at 22:00h (minimum IOP peak).

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Titanium and its alloys allow a wide range of applications as they have a distinct combination of characteristics, such as low density, high mechanical strength and excellent corrosion resistance. In addition, they also allow the combination of different phases and microstructures, which can be obtained as a function of the addition of alloying elements and through different processing parameters. In this context, the aim of this work has been the microstructural and mechanical evaluation of the Ti-16Nb alloy obtained by tape casting, having as object of comparison the different sintering temperatures and size of the niobium particles. The work was carried out through the development of five steps: i) preparation of powders and organic binders, which involves the separation and mixing of materials; ii) molding and cutting of samples; iii) sintering according to heating and cooling rates, temperatures and exposure time; iv) metallographic preparation, performed by grinding and polishing the samples v) metallographic and mechanical characterization, which involves optical and electronic microscopy tests, energy dispersive spectroscopy, X-ray diffractometry and Vickers hardness test. Regarding the evaluation of the samples, the results show that the sintering temperature is an important parameter, because at higher temperatures the samples showed greater changes in the microstructure and in the phases present in the alloy. The size of the niobium particle also influenced the study, and the samples with smaller particles were the ones that showed greater hardness and less porosity. In general, the porosity of the samples was between 30.8% and 14.1% and it decreased as the sintering temperature increased, contrary to what occurred with the hardness, which increased as the samples were sintered at higher temperatures. Microscopic evaluation showed few microstructural changes in samples sintered at 900 °C and 1000 °C, while at temperatures of 1100 °C and 1200 °C there was greater densification of the alloy and an increase in the  phase content of titanium in the samples. The mapping of the elements carried out in the energy dispersive spectroscopy test allowed us to determine that the  phase of titanium is rich in niobium, with this diffusion occurring more significantly at 1200 °C. X-ray diffraction highlighted the influence of temperature and particle size on the emergence of the  phase. Finally, Vickers hardness tests show that samples sintered at higher temperatures and with smaller grains have higher hardness values.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES