Abstract:The entropy generation in unsteady three-dimensional axisymmetric magnetohydrodynamics (MHD) nanofluid flow over a non-linearly stretching sheet is investigated. The flow is subject to thermal radiation and a chemical reaction. The conservation equations are solved using the spectral quasi-linearization method. The novelty of the work is in the study of entropy generation in three-dimensional axisymmetric MHD nanofluid and the choice of the spectral quasi-linearization method as the solution method. The effects of Brownian motion and thermophoresis are also taken into account. The nanofluid particle volume fraction on the boundary is passively controlled. The results show that as the Hartmann number increases, both the Nusselt number and the Sherwood number decrease, whereas the skin friction increases. It is further shown that an increase in the thermal radiation parameter corresponds to a decrease in the Nusselt number. Moreover, entropy generation increases with respect to some physical parameters.

Air pollution has become an environmental problem of public concern worldwide. In the present over Gopalpur village in Durgapur situated at 23°29ʹ52.67ʺ N and 87°23ʹ46.08ʺE. Meteorological parameters like temperature, humidity, wind speed and wind direction were also simultaneously recorded over the chosen site.Various statistical tools have been used for the analysis of the obtained result. The data obtained from the field work have been compared with the secondary data obtained from Durgapur Station of Central Pollution Control Board (CPCB). The temporal variations of the concentrations of PM 10 , SO X , NO X and O 3 have been explored and their relationships with different meteorological parameters have been identified. Concentration of PM 10 ranged from 53.803 to 271.325µg/m 3 , with a mean value of 136.689± 54.873 µg/m 3 ,80% of the monitored data exceeded the National Ambient Air Quality Standards (NAAQS) for PM 10 in the ambient atmosphere. The concentration of SO X over the site is found to lie between 14.219µg/m 3 to 390.041µg/m 3 , with a mean value of 104.601±103.860 µg/m 3 and 45 % of the total data exceeded the NAAQS for the concentration of SO X in the ambient air. The recorded concentration of NO X lies between 32.50 µg/m 3 -112.79 µg/m 3 , with a mean value of 66.99± 21.63 µg/m 3 and 20% of the monitored data is found to exceed the NAAQS for NO X in the atmosphere. Record of eight hour 00h). Detailed study shows that ozone has high positive correlation with temperature and high negative correlation with humidity. Atmospheric concentration of selected heavy metals including Lead (Pb), Copper (Cu), Manganese(Mn) and Cadmium (Cd) were also measured followed by the analysis of their probable sources. Wind rose has been constructed using WindRose PRO (Version 3.1.x). Industrial emission (Sponge Iron industries, Steel industries etc.), vehicular exhausts, open biomass burning, mining etc have been identified as the probable sources of the pollutants in the ambient atmosphere of Gopalpur.

The present study focuses on the spatio-temporal variation of nitrogen dioxide (NO2) during June 2013 to May 2015 and its futuristic emission scenario over an urban area (Durgapur) of eastern India. The concentration of ambient NO2 shows seasonal as well as site specific characteristics. The site with high vehicular density (Muchipara) shows highest NO2 concentration followed by industrial site (DVC- DTPS Colony) and the residential site (B Zone), respectively. The seasonal variation of ambient NO2 over the study area is portrayed by means of Geographical Information System based Digital Elevation Model. Out of the total urban area under consideration (114.982 km2), the concentration of NO2 exceeded the National Ambient Air Quality Standard (NAAQS) permissible limit over an area of 5.000 km2, 0.786 km2 and 0.653 km2 in post monsoon, winter and pre monsoon, respectively. Wind rose diagrams, correlation and regression analyses show that meteorology plays a crucial role in dilution and dispersion of NO2 near the earth’s surface. Principal component analysis identifies vehicular source as the major source of NO2 in all the seasons over the urban region. Coupled AMS/EPA Regulatory Model (AERMOD)–Weather Research and Forecasting (WRF) model is used for predicting the concentration of NO2. Comparison of the observed and simulated data shows that the model overestimates the concentration of NO2 in all the seasons (except winter). The results show that coupled AERMOD–WRF model can overcome the unavailability of hourly surface as well as upper air meteorological data required for predicting the pollutant concentration, but improvement of emission inventory along with better understanding of the sinks and sources of ambient NO2 is essential for capturing the more realistic scenario.

RESUMENDe abril a mayo de 2014 se llevó a cabo el monitoreo y análisis de varios contaminantes atmosféricos como material particulado (PM 10 ), dióxido de azufre (SO 2 ), dióxido de nitrógeno (NO 2 ), ozono (O 3 ), monóxido de carbono (CO) y amoniaco (NH 3 ), así como de parámetros meteorológicos (temperatura, humedad, y velocidad y dirección del viento), en tres sitios diferenciados (un área con alta densidad de tráfico vehicular, un área residencial y un área industrial) en una zona urbana del este de la India. El promedio máximo de la concentración ), así como la concentración promedio por hora más alta de CO (3.846 mg/m 3 ) en el sitio industrial pueden atribuirse a las emisiones de las industrias circundantes. El cálculo de los índices de calidad del aire (AQI, por sus siglas en inglés) muestra que tanto el sitio 1 (un área de tráfico congestionado con AQI = 71.68) corresponden a una categoría moderada de contaminación, en tanto que el sitio 2 (un área residencial con AQI = 22.69) se considera limpio. Este estudio detallado revela que la variación en las concentraciones de diversos contaminantes es una manifestación del efecto combinado de fuentes y patrones de emisión, la altura de la capa limítrofe planetaria y la meteorología. ABSTRACTMonitoring and analyses of various air pollutants like particulate matter (PM 10 ), sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), ozone (O 3 ), carbon monoxide (CO) and ammonia (NH 3 ), as well as meteorological parameters (temperature, humidity, wind speed and direction) have been performed for the period between April and May, 2014 at three different sites (an area with high vehicular density, a residential area and an industrial area) of an urban area in eastern India. The hourly average concentration of surface ozone is found maximum at the industrial site (70.085 µg/m