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The deterioration of materials due to the effect of atmospheric pollution generates a cost to society because the maintenance and replacement of degraded materials. Galvanised steel is used in electrical industry to build electrical transmission towers (ETT). The objective of the study was to estimate the annual maintenance cost of galvanised steel used in the construction of ETT. The maintenance cost for galvanised steel was estimated considering the cost of the material surface area and the difference between the maintenance interval of clean and contaminated areas. Maps of intervals and maintenance costs were obtained for galvanised steel (85 and 100 µm), which are the thicknesses regulated in Mexico for ETT. In addition, an ArcGis geographic information system was used for a spatial representation of data from the anthropogenic environment. The mapping of areas at risk of corrosion shows that in the northwest zone, ETT presents the highest maintenance costs for the year 2019. For galvanised steel thicknesses of 85 and 100 µm, there are annual costs of, respectively, 8.68 and 10.16 USD/m2. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has long been attributed mainly to the effect of pollutants such as sulfur dioxide. There are changes in the urban atmosphere's chemical composition due to the implementation of air quality policies focused on reducing the emission of sulfur dioxide and other pollutants. This study's objectives were to estimate and map the contribution of nitric acid on zinc's atmospheric corrosion process. METHODS: The impact of nitric acid on zinc is feasible to estimate using a function for a multi-pollutant situation. This function contemplates the sum of two contributions: one of nitric acid and another that includes sulfuric acid and climatic parameters. The multi- pollutant function is suitable to apply in areas without the strong influence of chlorides and tropical and subtropical climates, comparable to the Mexico City Metropolitan area. FINDINGS: The results showed that spatial and temporal estimation of corrosion rates in grams per square meter of zinc was made for 2015-2019, using data modeling in a geographic information system. The maps of corrosion rates allowed us to visualize that, in general, the "southwest" zone has the most significant effects and that the lowest corrosion rates were presented in 2019 as an outcome of the implementation of air quality programs. Furthermore, a contribution of nitric acid up to 32% to the zinc corrosion rate was estimated. CONCLUSION: The construction of corrosion rate maps provides a spatial and temporal estimate that allows visualizing areas where zinc materials are at risk corrosion due to the dispersion of atmospheric pollutants and climatic parameters. Likewise, it can represent a decision-making tool for the implementation of atmospheric corrosion studies of materials. [ABSTRACT FROM AUTHOR]

Aluminum pieces are often used in various industrial processes like automotive and aerospace manufacturing, as well as in ornamental applications, so it is necessary to develop processes to protect these materials, processes that can be industrialized to protect the aluminum as well or better than chromate treatments. The purpose of this research is to evaluate boric acid as an accelerator by optimizing its concentration in cerium conversion coatings (CeCC) with 10-minute immersion time with a concentration of 0.1 g L-1 over aluminum to protect it. The evaluation will be carried out by measuring anticorrosion properties with electrochemical techniques (polarization resistance, Rp, polarization curves, PC, and electrochemical impedance spectroscopy, EIS) in NaCl 3.5% wt. aqueous solution and surface characterization with scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

The morphology, composition, and corrosion performance of chromate conversion coatings (CCCs) formed on GALVALUME (Fe-Al-Zn) and galvanized steel (Fe-Zn) samples have been studied, and different immersion times (0, 10, 30, and 60 seconds) have been compared. The coated surfaces were analyzed using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements in a NaCl solution (3 wt pct). The electrochemical measurements were carried out using the polarization resistance, Tafel, and ac impedance methods. A nonuniform growth of the CCCs having a porous morphology and cracks that appear extended to the base metal was observed. The XRD patterns show that the coatings mainly consist of CrO3, Cr2O3, and traces of Cr2O. The electrochemical results show that GALVALUME presents a better behavior than that of the galvanized steel alloys at each dipping time. The SEM micrographs show that the galvanized steel treatments resulted in the formation of a more uniform film, but their protection barrier broke down faster than that of the GALVALUME samples in contact with the aggressive media. The samples that underwent the lowest degree of dissolution were those with a dipping time of 30 seconds. The difference in the corrosion protection given by the two substrate types could be attributed to the structural properties, grain size, composition, and roughness, which affect oxygen diffusion. [ABSTRACT FROM AUTHOR]

The article discusses pleural empyema due to salmonella enteritidis in a non-immunocompromised patient. Case report of a 54 year old man with a history of mitral valvulopathy; Manifestations of the disease; Medicine for treatment.