NUMERICAL MODELING DISTRIBUTION OF CONTAMINATING SUBSTANCES IN STREET CANYONS

In this study, we simulated the dynamics of the gas flow near a one-parameter model of the building. To study the gas tracing process, several types of barriers of various heights were applied. Ethylene - С2Н4 was chosen as an indicator gas. Numerical modeling was performed using the time-averaged Navier-Stokes (RANS) equations, with the Boussinesq approximation, by comparing the simulation results with the experimental results of famous authors. According to the results of the study, it was found that the use of the RANS model in conjunction with k-e Realizable (RLZ), kw SST (SST), DES k-e (DES) turbulence models yielded practically comparable results with small deviations, which made it possible to choose k-e Realizable turbulence models. In addition, it was found that with an increase in the height of the barrier, an increase in the retention properties in the region between the structure and the barrier is observed. In general, the numerical results are commensurate with the experimental values, which confirms the correctness of the mathematical and numerical models used. These studies can be applied in the future for a more detailed study of the influence of perpendicular flows of the spread of pollutants within the urban canyon.

Dispositivo automatizado para control de micro corrosión generada en convertidor de ozono instalado en área de producción de industria aeroespacial de Mexicali

Due to failures in ozone converters used in the aerospace industry and manufactured in a company located in the city of Mexicali, and that generated a health problem in commercial aircraft interiors due to the malfunction of ozone converters, the internal environment was evaluated of the company mentioned and located in the desert area of the northwest of the Mexican Republic. The analysis was carried out with specialized equipment and a device for detecting and controlling chemical substances derived from sulfur and deposited on metallic surfaces of electrical connections of ozone converters installed in a section of aircraft cabins. With the monitoring equipment, the corrosive environment in the interiors of the company was quickly detected and with the development of an electrical fault detection device in the ozone converters, the failures were reduced by 70%. Microanalysis was performed using the Electronic Scanning Microscopy (MBE) technique, to identify the contaminating substances deposited on the metallic surfaces of the electrical connections of the ozone converters, as well as the concentration levels of said substances. The automated device for micro corrosion control was designed, manufactured and tested, to detect periods of deposition of sulfur-derived chemicals. In addition, specialized filters were installed to reduce the entrance to the interiors of the company in Mexicali, and thus have a regulated environment and thus avoid the generation of micro corrosion. The study was conducted from 2017 to 2018.

Spatial Clusters of Children with Cleft Lip and Palate and Their Association with Polluted Zones in the Monterrey Metropolitan Area

This study examines the spatial structure of children with cleft lip and palate (CLP) and its association with polluted areas in the Monterrey Metropolitan Area (MMA). The Nearest Neighbor Index (NNI) and the Spatial Statistical Scan (SaTScan) determined that the CLP cases are agglomerated in spatial clusters distributed in different areas of the city, some of them grouping up to 12 cases of CLP in a radius of 1.2 km. The application of the interpolation by empirical Bayesian kriging (EBK) and the inverse distance weighted (IDW) method showed that 95% of the cases have a spatial interaction with values of particulate matter (PM10) of more than 50 points. The study also shows that 83% of the cases interacted with around 2000 annual tons of greenhouse gases. This study may contribute to other investigations applying techniques for the identification of environmental and genetic factors possibly associated with congenital malformations and for determining the influence of contaminating substances in the incidence of these diseases, particularly CLP.

Agricultural Use of Sewage Sludge in Paraná State, Brazil: A Decade of National Regulation

The agricultural use of sewage sludge brings benefits to soil and plant crops, but due to the possible presence of contaminating substances and pathogenic organisms it is necessary to follow the criteria for safe use for health and the environment. In Brazil, the Conama 375/06 Resolution established criteria and procedures for agricultural use of sewage sludge and Paraná is one of the few states in the country to use this alternative. This case study presents the management process and the results of the agricultural destination of the sludge in Paraná State, Brazil, from 2007, year in which the resolution came into force, to 2017. The management is carried out in two spheres of action: one in the context of the sludge management units (SMU) and another in the agricultural sphere. The sludge is provided free of charge to farmers, which reduces expenses with fertilizers and soil acidity correctives, resulting in economic and social benefits to the communities where it is used. However, from the year 2011 there was a reduction in the amount destined for agricultural use. The requirements of the national regulation make the process complex, overly bureaucratic and burdensome, requiring a review of its criteria.