Consideraciones geotécnicas en la construcción de 200 metros de túnel de la Mina "Escobal", en el nivel 1265, ubicado en el municipio de San Rafael Las Flores, departamento de Santa Rosa, Guatemala

La investigación compila una serie de estudios geotécnicos, para evaluar un tramo crítico, dentro del túnel de la mina Escobal. Dichos estudios, presentan las consideraciones geotécnicas generales, que las obras subterráneas de cualquier tipo deben preveer y llevar a cabo. La sección típica de este túnel es de 5 m de ancho por 6 m de altura tipo bóveda. El sostenimiento que utiliza de manera general es electromalla, pernos de anclaje o bulones y concreto lanzado. Se realizó un análisis de la geología regional, para emplazar el sitio de estudio en el contexto general geotécnico y proyectar el comportamiento del macizo rocoso como una estructura general y llevarnos hasta la geología local, donde se describen cada una de las formaciones geológicas y sus características litológicas que se encuentran donde se desarrolla el proyecto miner

Assessment of NAAPS-RA performance in Maritime Southeast Asia during CAMP2Ex

Monitoring and modeling aerosol particle life cycle in Southeast Asia (SEA) is challenged by high cloud cover, complex meteorology, and the wide range of aerosol species, sources, and transformations found throughout the region. Satellite observations are limited, and there are few in situ observations of aerosol extinction profiles, aerosol properties, and environmental conditions. Therefore, accurate aerosol model outputs are crucial for the region. This work evaluates the Navy Aerosol Analysis and Prediction System Reanalysis (NAAPS-RA) aerosol optical thickness (AOT) and light extinction products using airborne aerosol and meteorological measurements from the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) conducted in 2019 during the SEA southwest monsoon biomass burning season. Modeled AOTs and extinction coefficients are compared to those retrieved with a high spectral resolution lidar (HSRL-2). Agreement between simulated and retrieved AOT (R2Combining double low line 0.78, relative bias Combining double low line-5 %, normalized root mean square error (NRMSE) Combining double low line 48 %) and aerosol extinction coefficients (R2Combining double low line 0.80, 0.81, and 0.42; relative bias Combining double low line 3 %, -6 %, and -7 %; NRMSE Combining double low line 47 %, 53 %, and 118 % for altitudes between 40-500, 500-1500, and >1500 m, respectively) is quite good considering the challenging environment and few opportunities for assimilations of AOT from satellites during the campaign. Modeled relative humidities (RHs) are negatively biased at all altitudes (absolute bias Combining double low line-5 %, -8 %, and -3 % for altitudes 1500 m, respectively), motivating interest in the role of RH errors in AOT and extinction simulations. Interestingly, NAAPS-RA AOT and extinction agreement with the HSRL-2 does not change significantly (i.e., NRMSE values do not all decrease) when RHs from dropsondes are substituted into the model, yet biases all move in a positive direction. Further exploration suggests changes in modeled extinction are more sensitive to the actual magnitude of both the extinction coefficients and the dropsonde RHs being substituted into the model as opposed to the absolute differences between simulated and measured RHs. Finally, four case studies examine how model errors in RH and the hygroscopic growth parameter, γ, affect simulations of extinction in the mixed layer (ML). We find NAAPS-RA overestimates the hygroscopicity of (i) smoke particles from biomass burning in the Maritime Continent (MC) and (ii) anthropogenic emissions transported from East Asia. This work mainly provides insight into the relationship between errors in modeled RH and simulations of AOT and extinction in a humid and tropical environment influenced by a myriad of meteorological conditions and particle types. These results can be interpreted and addressed by the modeling community as part of the effort to better understand, quantify, and forecast atmospheric conditions in SEA. Copyright © 2022 Eva-Lou Edwards et al.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Aircraft Observations of Turbulence in Cloudy and Cloud-Free Boundary Layers Over the Western North Atlantic Ocean From ACTIVATE and Implications for the Earth System Model Evaluation and Development

This study examines boundary layer turbulence derived from high temporal resolution meteorological measurements from 40 research flights over the western North Atlantic Ocean during the 2020 deployments of ACTIVATE. Frequency distributions of various turbulent quantities reveal stronger turbulence during the winter deployment than in summer and for cloud-topped than in cloud-free boundary layers during the summer deployment. Maximum turbulence kinetic energy (TKE) is most often within cloud from observations in winter and summer, whereas it is mostly below cloud in both seasons by a global model turbulence parameterization. Bivariate frequency distributions are consistent with the bivariate Gaussian probability distribution functions assumed for the closure of higher-order turbulence/shallow convection parameterizations used by some global models. Turbulence simulated by the Community Atmosphere Model version 6 and the Energy Exascale Earth System Model Atmosphere Model version 2 using such parameterizations is not as strong as observed, with more TKE going into vertical wind perturbations rather than into zonal wind perturbations as observed, suggesting that the treatment of turbulence in Earth system models still needs to be further improved. © 2022. American Geophysical Union. All Rights Reserved.6 month embargo; first published: 15 September 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Influence of fillers concentration on electrical properties of polystyrene matrix doped by gold nanoparticles and 8HQ

34.70.+e Charge transfer, 77.80.Fm Switching phenomena, 91.60.Tn Transport properties, 82.35.Np Nanoparticles in polymers,