RESUMO
As the main components of the building envelope, construction materials have a straight relation with air contaminants from anthropogenic origins. Titanium dioxide has been recently applied in construction industry products since its photocatalytic properties can be used for pollutant degradation purposes. This study evaluated the performance of cement-based mortars with the incorporation of TiO2 nanoparticles and mineral admixtures. Six mortar compositions were defined by considering two reference mixes (with and without TiO2 incorporation), two mineral admixtures (bentonite and metakaolin) as partial cement replacement and one waste from ornamental stone processing in two levels of partial substitution of natural sand. Consistency index, density, and entrained air content of mixtures were investigated at fresh state. Compressive strength, water absorption, sorptivity, and micrographs from scanning electron microscopy were used to characterize mortars at hardened state. It was observed that incorporation of TiO2 does not considerably change mortar's properties at fresh and hardened state, despite a denser microstructure and improved interfacial transition zone. In general, the relation between the water-to-cement ratio and porosity on the performances of TiO2-added mortars was shown, which is strongly related to their photocatalytic efficiency. Metakaolin mixtures were more efficient to NO conversion, and high selectivity was observed for the bentonite mortars.
Assuntos
Bentonita , Titânio , Titânio/química , Minerais , ÁguaRESUMO
O objetivo do presente trabalho foi caracterizar o desenvolvimento do processo de rigor mortis dos músculos Triceps brachii e Extensor/Flexor, de seis carcaças de javalis, criados semiextensivos, durante o pré-resfriamento industrial e a maciez da carne, utilizando medidas de temperatura de carcaças e da câmara de resfriamento, de pH, de comprimento de sarcômero e da força de cisalhamento, nos intervalos de tempo de 0,5; 3,0; 5,0; 7,0; 9,0; 12,0 e 24,0 horas após a sangria. A temperatura da câmara fria variou de 19,6oC (0,5h) a 0,5oC (24h) e a temperatura média das carcaças foi de 39,07oC e 0,28oC, respectivamente. O pH médio inicial do músculo Triceps brachii foi de 6,64 e o final 5,52 e nos músculos Extensor/Flexor foi de 6,79 (0,5h) e 5,68 (24h), sendo de maior valor nos músculos Extensor/Flexor. A caracterização da contração máxima de sarcômero durante o processo de rigor mortis ocorreu na 7a hora após sangria no músculo Triceps brachii (1,61mm) e na 9a hora nos músculos Extensor/Flexor (1,63 mm) e o músculo T. brachii apresentou maior tamanho de sarcômero. As perdas por cozimento foram proporcionais à força de cisalhamento onde as amostras de carne da paleta de javali foram consideradas macias, ou seja, inferiores a 5kg.
The objective of the present work was to characterize the development of the process of rigor mortis of the Triceps brachii and Extensor/Flexor muscles, of 06 wild boars, created semi-extensive, during the industrial pre-chilling and tenderness of the meat, using measures of temperature of carcasses and of the cold room, of pH, of sarcomere length and of the shear force, in the intervals of time of 0.5; 3.0; 5.0; 7.0; 9.0; 12.0 and 24.0 hours after exsanguination. The temperature of the cold room changed from 19.6oC (0.5h) to 0.5oC (24h) and the mean temperature of the carcasses was from 39.07oC to 0.28oC, respectively. The mean initial pH of the muscle Triceps brachii was of 6.64 and final of 5.52 and Extensor/Flexor muscles was 6.79 (0.5h) and 5.68 (24h), being a bigger value in the muscles . Extensor/Flexor. The characterization of maximum contraction of the sarcomere during the of rigor mortis process took place in the 7th hour after exsanguination in the muscle Triceps brachii and in the 9th hour in the muscles Extensor/Flexor and the muscle Triceps brachii presented bigger sarcomere lenght. The cooking loss was proportional to the shear force where the samples of meat of wild boar shoulder were considered tender, in other words, inferior to 5kg.
