Browsing by Author "Anuradha Shukla"

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Assessment of atmospheric aerosols over Varanasi: Physical, optical and chemical properties and meteorological implications
(Elsevier Ltd, 2020) Pradeep Kumar; Vineet Pratap; Akhilesh Kumar; Arti Choudhary; Rajendra Prasad; Anuradha Shukla; R.P. Singh; Abhay Kumar Singh
The present paper reports the results derived from PM2.5 and PM10 concentrations during October 2016–May 2018 using MICROTOPS-II Sunphotometer and high volume samplers at Varanasi. Observed data were categorized and analyzed in order to understand the nature, source of origin and variability with seasons. Observations showed aerosol mass loading during the post-monsoon 2016 and winter 2017 as compared to the pre-monsoon 2018 values, which typically exceed national standard. The close relationships between PM2.5 and PM10 during post-monsoon (r = 0.571) and winter (r = 0.799) suggested that both type of particulates might have originated from the same source. Further, the PM2.5/PM10 indicated that the fine particles were dominantly present during the post-monsoon and winter season where as coarse particles were found dominant in the pre-monsoon season. The measured high values of aerosol optical depth (AOD) and angstrom exponent (AE) during post-monsoon and winter attributed to the accumulation of aerosols from sources and biomass/crop residue burning in the surrounding region and low dispersal due to shallow boundary layer and lower wind velocity. In contrast during pre-monsoon months the aerosols were accumulated as a mixture of transported from deserts and other far away regions including mineral from earth crust. The effect of meteorological parameters (temperature, wind speed and relative humidity) was also studied. Temperature did not show any relation during the pre monsoon when it was quite high, whereas during the winter months it showed negative trend with concentration. Wind showed negative correlation during the whole observation period. Relative humidity showed weak positive correlation during winter months for PM2.5 and PM10 where as PM2.5 did not show any relation during pre and post monsoon. PM10 showed weak negative relation during pre monsoon months. In order to understand elemental and ionic composition Scanning electron microscope (SEM) coupled with energy dispersive X-ray microanalyzer (EDX) analysis were done which showed dominant presence of C, F, O, Si, N, Na, K, Al, Ca and S. The following trend SO42− > NO3− > Na+> Ca2+> K+> Cl− > F− > Mg2+> Li+ was observed from the Ion chromatograph (IC) analysis. The source for these elements may have been different industrial activities, biomass burning and vehicular emissions. The results are useful for further planning of city developments and climate studies. © 2020 Elsevier Ltd
Rapid immobilization of viable Bacillus pseudomycoides in polyvinyl alcohol/glutaraldehyde hydrogel for biological treatment of municipal wastewater
(Springer, 2020) Tithi Mehrotra; Mohammad Nawaid Zaman; Bhim Bali Prasad; Anuradha Shukla; Srijan Aggarwal; Rachana Singh
A new approach for easy synthesis of Bacillus pseudomycoides immobilized polyvinyl alcohol (PVA)/glutaraldehyde (GA) hydrogel for application in a wastewater treatment system is reported. Optimization studies revealed that GA/PVA mass ratio of 0.03 and acidic pH of 2 were required for hydrogel synthesis and eventually for bacterial cell immobilization. The synthesized crosslinked matrix possessed a pore size suitable for microbial cell entrapment while maintaining cell accessibility to external environment for bioremediation. Possible crosslinking and bacterial cell immobilization in the hydrogel were evidenced by FTIR, XRD, and SEM studies, respectively. Further, the extent of crosslinking of GA with PVA was investigated and confirmed by transmittance and permeability experiments. The viability and proliferation of hydrogel embedded cells (after 25 days) was confirmed by confocal fluorescence microscopy which also indicated that acidic pH of polymer solution did not affect the immobilized live cells. B. pseudomycoides immobilized hydrogel were demonstrated to be effective for treatment of municipal wastewater and reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and protein content below the recommended levels. Overall, the results from this bench-scale work show that employing bacteria-embedded PVA/GA hydrogel for the treatment of municipal wastewater yield promising results which should be further explored in pilot/field-scale studies. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Real world driving dynamics characterization and identification of emission rate magnifying factors for auto-rickshaw
(Technoscience Publications, 2020) Arti Choudhary; Pradeep Kumar; Manisha Gaur; Vignesh Prabhu; Anuradha Shukla; Sharad Gokhale
Most urgent transport related problems in India are traffic congestion and concomitant air pollutant emissions. During traffic flow, the common causes of congestion in urban centres are pedestrian interruption, unregulated traffic signals, unregulated bus stoppages and unauthorized roadside parking, which together, particularly during peak hours, create erratic traffic pattern causing higher emissions. In this study, we characterized auto-rickshaw driving dynamics by instantaneous measurements of speed and emission at different times of the day. Traffic speed is an important factor that is perceived by commuters. The speed variables and traffic volume are used as a base variable to examine the traffic flow patterns. The speed variables such as average speed (AS), velocity noise (VN, standard deviation of speed), and the coefficient of variation of speed (CV, the ratio of VN and AS) were examined with respect to traffic volume. The polynomial fit of CV shows three distinct zones of variations with increasing traffic volume, explaining the dynamics of traffic flow. Further, time, speed and mileage variable were investigated for the emission rate analysis in different traffic flow pattern. The analysis depicted that the combined factor of lower speed (speed ≤12 km/h) and higher time of travel in correspondence cause higher emission rate. Similarly, vehicle mileage of ≥52, 000 km has significant impact on emission for pollutants CO, HC and NOx. The results provide real-time information on traffic flow characteristics and impacts of dynamic and age variables on emission rate in on-road driving condition, which may be useful for the public and transport related agencies. © 2020 Technoscience Publications. All rights reserved.