998 resultados para atmospheric trace gases
Resumo:
En el vídeo se explica com en muchos de los yacimientos hay cantidades importantes de gas de materia aislada, es el llamado gas natural. Este se compone básicamente de metano, junto con otras pequeñas cantidades de etano, propano y butano.
Resumo:
Resumen tomado de la revista
Resumo:
Resumen basado en el de la publicaciòn
Resumo:
Este título se ha desarrollado específicamente para la enseñanza de la Química en el nuevo Nivel Avanzado (A2) de septiembre del año dos mil y aprobado por el OCR (uno de los tres órganos que ofrece la gama completa de las cualificaciones académicas y profesionales del Reino Unido). Está dividido en cuatro secciones:estados de la materia ; diagramas de fases ; distribución entre las fases ; ley de Raoult y destilación. El módulo se basa en el material del libro de texto Química 1, sin embargo, el material de apoyo se puede encontrar en la publicación Química 2. Al final de cada capítulo hay ejercicios con preguntas de autoevaluación para el estudio independiente. Tiene las respuestas a las preguntas de auto-evaluación, glosario, e índice .
Resumo:
Resumen basado en el de la publicación
Resumo:
Atmospheric downwelling longwave radiation is an important component of the terrestrial energy budget; since it is strongly related with the greenhouse effect, it remarkably affects the climate. In this study, I evaluate the estimation of the downwelling longwave irradiance at the terrestrial surface for cloudless and overcast conditions using a one-dimensional radiative transfer model (RTM), specifically the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). The calculations performed by using this model were compared with pyrgeometer measurements at three different European places: Girona (NE of the Iberian Peninsula), Payerne (in the East of Switzerland), and Heselbach (in the Black Forest, Germany). Several studies of sensitivity based on the radiative transfer model have shown that special attention on the input of temperature and water content profiles must be held for cloudless sky conditions; for overcast conditions, similar sensitivity studies have shown that, besides the atmospheric profiles, the cloud base height is very relevant, at least for optically thick clouds. Also, the estimation of DLR in places where radiosoundings are not available is explored, either by using the atmospheric profiles spatially interpolated from the gridded analysis data provided by European Centre of Medium-Range Weather Forecast (ECMWF), or by applying a real radiosounding of a nearby site. Calculations have been compared with measurements at all sites. During cloudless sky conditions, when radiosoundings were available, calculations show differences with measurements of -2.7 ± 3.4 Wm-2 (Payerne). While no in situ radiosoundings are available, differences between modeling and measurements were about 0.3 ± 9.4 Wm-2 (Girona). During overcast sky conditions, when in situ radiosoundings and cloud properties (derived from an algorithm that uses spectral infrared and microwave ground based measurements) were available (Black Forest), calculations show differences with measurements of -0.28 ± 2.52 Wm2. When using atmospheric profiles from the ECMWF and fixed values of liquid water path and droplet effective radius (Girona) calculations show differences with measurements of 4.0 ± 2.5 Wm2. For all analyzed sky conditions, it has been confirmed that estimations from radiative transfer modeling are remarkably better than those obtained by simple parameterizations of atmospheric emissivity.
Resumo:
The North Atlantic Oscillation (NAO) is an important large-scale atmospheric circulation that influences the European countries climate. This study evaluated NAO impact in air quality in Porto Metropolitan Area (PMA), Portugal, for the period 2002-2006. NAO, air pollutants and meteorological data were statistically analyzed. All data were obtained from PMA Weather Station, PMA Air Quality Stations and NOAA analysis. Two statistical methods were applied in different time scale : principal component and correlation coefficient. Annual time scale, using multivariate analysis (PCA, principal component analysis), were applied in order to identified positive and significant association between air pollutants such as PM10, PM2.5, CO, NO and NO2, with NAO. On the other hand, the correlation coefficient using seasonal time scale were also applied to the same data. The results of PCA analysis present a general negative significant association between the total precipitation and NAO, in Factor 1 and 2 (explaining around 70% of the variance), presented in the years of 2002, 2004 and 2005. During the same years, some air pollutants (such as PM10, PM2.5, SO2, NOx and CO) present also a positive association with NAO. The O3 shows as well a positive association with NAP during 2002 and 2004, at 2nd Factor, explaining 30% of the variance. From the seasonal analysis using correlation coefficient, it was found significant correlation between PM10 (0.72., p<0.05, in 2002), PM2.5 (0 74, p<0.05, in 2004), and SO2 (0.78, p<0.01, in 2002) with NAO during March-December (no winter period) period. Significant associations between air pollutants and NAO were also verified in the winter period (December to April) mainly with ozone (2005, r=-0.55, p.<0.01). Once that human health and hospital morbidities may be affected by air pollution, the results suggest that NAO forecast can be an important tool to prevent them, in the Iberian Peninsula and specially Portugal.
Resumo:
La presente investigación basó su estudio y aplicación al proceso de “control de costos” de gases líquidos, realizados por la empresa British Oxigen Company - BOC Gases Venezuela, y determinó como la eficiencia propuesta como una alternativa en la gestión, se basa en el control de los procesos productivos, enfocándose en la reducción de costos y la generación de valor en el producto. En cuanto al objetivo de la investigación es “Contribuir en la gestión más eficaz de los procesos en una empresa privada”, mediante la aplicación de la herramienta gerencial de administración de costos, para optimizar los recursos en el cumplimiento de las necesidades del mercado y evaluar la incidencia del cambio de los procesos sobre los resultados de la empresa. En el 2006, British Oxigen Company - BOC Gases Venezuela participa en un proceso de fusión, que generó oportunidades de mejoras y cambios a sus procesos internos y externos, y a su vez las disposiciones gerenciales se enfocaron en la optimización de los procesos de producción, logística, administración y ventas, mediante la optimización por el uso adecuado de sus recursos. Al aplicarse el mejoramiento del proceso de “Control de Costos” mediante la aplicación de la herramienta de costeo y gestión gerencial, la cual sirvió de apoyo en la identificación de oportunidades y en la toma de decisiones gerenciales. Los resultados de la investigación demostraron un mejoramiento del proceso a través del cambio de las actividades del proceso de “Control de Costos” para generar valor en el resultado final del proceso
National Oceanic and Atmospheric Administration: Center for Operational Oceanographic Products and S