COMPARISON OF TWO STAINING METHODS FOR ANODIZING IN ALLOY 6063 ALUMINUM PROFILES
Background: Aluminum stands out for being a light, corrosion-resistant, and recyclable metal, achieving wide coverage in the market. When incorporated into alloying elements, it is possible to acquire other desirable characteristics. Alloy 6063, intended for architectural purposes, has aesthetic, structural, and strength functions. Anodized finishing is performed through an electrolytic process, ensuring a more resistant aluminum oxide film than that formed naturally. For decorative purposes, the anodic film coloration can be performed by several methodologies, in this case, for the coloration by organic adsorption, with the use of aniline, and the electrolytic coloration, composed of tin sulfate salts, both for obtaining the black color. Aim: Compare of two different staining methods on the surface of anodized profiles of aluminum alloy 6063. Methods: Profile samples were collected and tests were carried out to measure the thickness of the anodic layer, immersion tests with 3,5 percent sodium chloride, for 1000 hours, and neutral saline mist, for 600 hours. Results and Discussion: Both methodologies proved to be resistant to immersion tests with sodium chloride, as well as with neutral saline mist, and these tests are quite aggressive and provide corrosion of the material when not well treated. Corrosion points were only seen at the intersections performed, and in the rest of thearea, no points were detected. Conclusions: The result of both methodologies was positive, considering tht there was no corrosion in the tested samples, except in the intersections performed, as well as the maintenance of the color in both tested methodologies, which was not expected in the literature. For future work, it is suggested to deepen the study to perform electrochemical impedance spectroscopy tests for exaluate the strength of the anodic film and perform anodizing with the same parameters, however, with different anilines to analyze their behavior.
Read ArticleMODELING OF THE NITROGEN PARAMETER OF THE PARAÍBA DO SUL RIVER USING THE QUAL-UFMG METHOD
Background: Due to population growth and increased use of water resources, there has been a need to implement management measures to control and monitor river parameters. Aims: This study aims to demonstrate the application of mathematical modeling using the QUAL-UFMG model for studying nitrogen concentration in the Paraíba do Sul River located in Volta Redonda. Methods: Through mathematical modeling, it is possible to identify areas of greater impact, evaluate the effectiveness of control measures, and propose a strategy to improve water quality and preserve the balance of local aquatic ecosystems. Results: The results obtained during the study showed that the nitrogen parameters and their derivatives are within the pre-established limits set by CONAMA. Discussion: During the modeling, it was observed that there is a tendency for nitrate levels to increase along the points, indicating good self-purification of the river. Organic nitrogen values increase along the points, which is due to the contribution of sewage discharge along the course of the river, as organic nitrogen and ammonia have a physiological origin in domestic sewage. Conclusions: Through the QUAL-UFMG model, it was possible to validate the conducted analyses and create future projections of the water quality in the Paraíba do Sul River along the studied points.
Read ArticleCOMPARATIVE STUDY ON ANTIOXIDANT ACTIVITY OF SALVIA NEMOROSA L. FROM TWO DIFFERENT LOCATIONS
In order to investigate the antioxidant activity of Salvia nemorosa L. collected from Ahar and Urmia regionsin Iran at different growth stages, aerial parts of sage after collecting were dried, and for measurement, the abilityof scavenge DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical in different concentrations (0.025, 0.05, 0.07,0.1, 0.2, 0.04 and 0.6) of methanolic extracts were prepared. The result showed that the ability to scavenge DPPHradical and amount of inhibition percent of vegetative stage leaves, flowering stage leaves, and flowers increasedwith increasing concentrations of methanolic extracts from 0.25 to 0.6 mg/mL. In the region of Urmia, the highestamount of DPPH inhibition there was in vegetative stage leaves, and the lowest amount of DPPH inhibition wasseen in flowers. In Ahar regions, unlike the Urmia region, the highest amount of DPPH inhibition there was inflowers, but the lowest of DPPH inhibition was seen in flowering stage leaves. Also, the content of inhibition ofDPPH in Ahar and Urmia regions similarly increased between two phenological stages (vegetative stage leaves,flowering stage leaves, and flowers) in 0.4 mg/mL and 0.6 mg/mL concentrations.
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