Academic literature on the topic 'Tula Site (Tula de Allende, Mexico)'

ABSTRACTSpectroscopy technique is used for various applications, for example in archaeology, in order to analyze samples of floors, including material excavation sites. In this work the floor samples that were found in two rooms belonging to a house in a residential Hispanic area, at different stratigraphic levels corresponding to the classical period, as well as samples that were collected in two deposits of lime (El Refugio and El Llano) around the site mentioned were analyzed. The characterization of the samples of the archaeological site Chingú in Tula de Allende in the state of Hidalgo was carried out by using Scanning Electron Microscopy (SEM) to observe the morphology of the samples and Energy Dispersive X-ray Spectroscopy (EDS) to analyze the composition of cementitious material of the floors and natural material of lime deposits. Comparing these samples with other archaeological works of literature, the morphology and composition of manufactured floors will be discussed.

Pollutant emissions and their contribution to local and regional air quality at the industrial area of Tula were studied during a four-week period as part of theMILAGROinitiative. A recurrent shallow stable layer was observed in the morning favoring air pollutants accumulation in the lower 100 m atmospheric layer. In the afternoon the mixing layer height reached 3000 m, along with a featuring low level jet which was responsible of transporting air pollutants at regional scales. Average PM10at Jasso (JAS) and Tepeji (TEP) was 75.1 and 36.8 μg/m3, respectively while average PM2.5was 31.0 and 25.7 μg/m3. JAS was highly impacted by local limestone dust, while TEP was a receptor of major sources of combustion emissions with 70% of the PM10constituted by PM2.5. Average hourly aerosol light absorption was 22 Mm−1, while aerosol scattering (76 Mm−1) was higher compared to a rural site but much lower than at Mexico City.δ13C values in the epiphyteTillandsia recurvatashow that the emission plume directly affects the SW sector of Mezquital Valley and is then constrained by a mountain range preventing its dispersion. Air pollutants may exacerbate acute and chronic adverse health effects in this region.

Abstract. One of the most challenging tasks for chemical transport models (CTMs) is the prediction of the formation and partitioning of the major semi-volatile inorganic aerosol components (nitrate, chloride, ammonium) between the gas and particulate phases. In this work the PMCAMx-2008 CTM, which includes the recently developed aerosol thermodynamic model ISORROPIA-II, is applied in the Mexico City Metropolitan Area in order to simulate the formation of the major inorganic aerosol components. The main sources of SO2 (such as the Miguel Hidalgo Refinery and the Francisco Perez Rios Power Plant) in the Mexico City Metropolitan Area (MCMA) are located in Tula, resulting in high predicted PM1 (particulate matter with diameter less than 1 μm) sulfate concentrations (over 25 μg m-3) in that area. The average predicted PM1 nitrate concentrations are up to 3 μg m−3 (with maxima up to 11 μg m−3) in and around the urban center, mostly produced from local photochemistry. The presence of calcium coming from the Tolteca area (7 μg m−3) as well as the rest of the mineral cations (1 μg m−3 potassium, 1 μg m−3 magnesium, 2 μg m−3 sodium, and 3 μg m−3 calcium) from the Texcoco Lake resulted in the formation of a significant amount of aerosol nitrate in the coarse mode with concentrations up to 3 μg m−3 over these areas. PM1−10 (particulate matter with diameter between 1 and 10 μm) chloride is also high and its concentration exceeds 2 μg m−3 in Texcoco Lake. PM1 ammonium concentrations peak at the center of Mexico City (2 μg m−3) and the Tula vicinity (2.5 μg m−3). The performance of the model for the major inorganic PM components (sulfate, ammonium, nitrate, chloride, sodium, calcium, and magnesium) is encouraging. At the T0 measurement site, located in the Mexico City urban center, the average measured values of PM1 sulfate, nitrate, ammonium, and chloride are 3.5 μg m−3, 3.5 μg m−3, 2.1 μg m−3, and 0.36 μg m−3, respectively. The corresponding predicted values are 3.7 μg m−3, 2.7 μg m−3, 1.7 μg m−3, and 0.25 μg m−3. High sulfate concentrations are associated with the transport of sulfate from the Tula vicinity, while in periods where southerly winds are dominant; the concentrations of sulfate are low. The underprediction of nitrate can be attributed to the underestimation of OH levels by the model during the early morning. Ammonium is sensitive to the predicted sulfate concentrations and the nitrate levels. The performance of the model is also evaluated against measurements taken from a suburban background site (T1) located north of Mexico City. The average predicted PM2.5 (particulate matter with diameter less than 2.5 μm) sulfate, nitrate, ammonium, chloride, sodium, calcium, and magnesium are 3.3, 3.2, 1.4, 0.5, 0.3, 1.2, and 0.15 μg m−3, respectively. The corresponding measured concentrations are 3.7, 2.9, 1.5, 0.3, 0.4, 0.6, and 0.15 μg m−3. The overprediction of calcium indicates a possible overestimation of its emissions and affects the partitioning of nitric acid to the aerosol phase resulting occasionally in an overprediction of nitrate. Additional improvements are possible by improving the performance of the model regarding the oxidant levels, and revising the emissions and the chemical composition of the fugitive dust. The hybrid approach in which the mass transfer to the fine aerosol is simulated using the bulk equilibrium assumption and to the remaining aerosol sections using a dynamic approach, is needed in order to accurately simulate the size distribution of the inorganic aerosols. The bulk equilibrium approach fails to reproduce the observed coarse nitrate and overpredicts the fine nitrate. Sensitivity tests indicate that sulfate concentration in Tula decreases by up to 0.5 μg m−3 after a 50% reduction of SO2 emissions while it can increase by up to 0.3 μg m−3 when NOx emissions are reduced by 50%. Nitrate concentration decreases by up to 1 μg m−3 after the 50% reduction of NOx or NH3 emissions. Ammonium concentration decreases by up to 1 μg m−3, 0.3 μg m−3, and 0.1 μg m−3 after the 50% reduction of NH3, NOx, and SO2 emissions, respectively.

AbstractDiscovery of dozens of broken ceramic roof ornaments (almenas) on the floor abutting the front (western) margin of an elite residence (Structure Q-1) at Cihuatan, El Salvador provides a new context for this category of artifacts. While relatively well-known from sites in the Valley of Mexico, elsewhere in Mesoamericaalmenashave been documented only from a single Teotihuacan-style structure at the lowland Maya site of Tikal, one structure at Mayapan, and possibly at a few other sites in Yucatan. A preliminary program to reconstruct a portion of the many box-likealmenasat Cihuatan, of a date much later than the one from Tikal, generated seven relatively complete examples of this form, indicated that fragments of perhaps another 50 had been recovered, and that they were used in pairs. The reconstructed sample provides an important demonstration of the ornamentation on an elite residence and also reveals much about how Structure Q-1 and surrounding buildings came to an end, arounda.d.1200. At least eight other buildings at Cihuatan had been adorned withalmenas,each building having examples of one specific shape, possibly unique to this city. Comparisons with Aztec and earlier Mexican forms suggest cultural connections, perhaps via Tula. These findings strongly suggest Mexican influences for the use and forms of roof ornaments at Cihuatan.

Technical and financial analysis are essential in every industrial process for decision-making in the optimization of results. However, they need to increase their efficiency, as well as greater use of security and reliability resources and enforcement in cost control systems, are guidelines that increase day by day, compared to this; electricity production is of great importance in terms of progress in Mexico, because both commercial businesses, industrial enterprises and households depend heavily on their proper management. This theoretical work is developed from a technical-financial methodology, carried out within the national electricity system of the Federal Electricity Commission, in this case analyzes the Francisco Pérez Ríos thermoelectric plant, which at present has five electric power generating units, located in Tula de Allende, Hidalgo, the contribution of this research is to seek the benefit in saving chemical treatment in the cooling towers from the information generated from the area Financial.