Faculty Publications
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Item Characterization and proinflammatory response of airborne biological particles from wastewater treatment plants(2011) Gangamma, S.; Patil, R.S.; Mukherji, S.Wastewater contains a variety of microorganisms, and unit operations in the plants could release these biological components into the air environment. These airborne biological particles could have adverse health effects on plant workers and the downwind population. This study provides a first report on the concentration and characterization of the airborne biological particles in six wastewater treatment plants in Mumbai, India. The study indicates that 49% and 27% of the samples exceed, respectively, the exposure limit for airborne endotoxin and bacteria in occupational settings. Endotoxin was identified as the single most important component of the particulate matter responsible for induction of proinflammatory indicator (tumor necrosis factor-?) in in vitro assay. Identification of several clinically important bacterial species in the samples suggests that the workers at the treatment plant are exposed to opportunistic and infectious bacteria. Principal component analysis was used to identify the groups among the bacterial species which serves as the signature for transport study. Analysis also shows that the component related to spore-forming bacteria is present in all samples. © 2011 American Chemical Society.Item Item Characteristics of airborne bacteria in Mumbai urban environment(Elsevier, 2014) Gangamma, S.Components of biological origin constitute small but a significant proportion of the ambient airborne particulate matter (PM). However, their diversity and role in proinflammatory responses of PM are not well understood. The present study characterizes airborne bacterial species diversity in Mumbai City and elucidates the role of bacterial endotoxin in PM induced proinflammatory response in ex vivo. Airborne bacteria and endotoxin samples were collected during April-May 2010 in Mumbai using six stage microbial impactor and biosampler. The culturable bacterial species concentration was measured and factors influencing the composition were identified by principal component analysis (PCA). The biosampler samples were used to stimulate immune cells in whole blood assay. A total of 28 species belonging to 17 genera were identified. Gram positive and spore forming groups of bacteria dominated the airborne culturable bacterial concentration. The study indicated the dominance of spore forming and human or animal flora derived pathogenic/opportunistic bacteria in the ambient air environment. Pathogenic and opportunistic species of bacteria were also present in the samples. TNF-? induction by PM was reduced (35%) by polymyxin B pretreatment and this result was corroborated with the results of blocking endotoxin receptor cluster differentiation (CD14). The study highlights the importance of airborne biological particles and suggests need of further studies on biological characterization of ambient PM. © 2014 Elsevier B.V.Item Performance, emission, and combustion characteristics of twin-cylinder common rail diesel engine fuelled with butanol-diesel blends(Springer Verlag service@springer.de, 2017) Lamani, V.T.; Yadav, A.K.; Gottekere, K.N.Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~ 4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NOx), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NOx, and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel. © 2017, Springer-Verlag GmbH Germany.Item Source apportionment studies on particulate matter (PM10 and PM2.5) in ambient air of urban Mangalore, India(Academic Press, 2018) Kalaiarasan, G.; Mohan Balakrishnan, R.M.; Sethunath, N.A.; Manoharan, S.Particulate matter (PM10 and PM2.5) samples were collected from six sites in urban Mangalore and the mass concentrations for PM10 and PM2.5 were measured using gravimetric technique. The measurements were found to exceed the national ambient air quality standards (NAAQS) limits, with the highest concentration of 231.5 ?g/m3 for PM10 particles at Town hall and 120.3 ?g/m3 for PM2.5 particles at KMC Attavar. The elemental analysis using inductively coupled plasma optical emission spectrophotometer (ICPOES) revealed twelve different elements (As, Ba, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sr and Zn) for PM10 particles and nine different elements (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) for PM2.5 particles. Similarly, ionic composition of these samples measured by ion chromatography (IC) divulged nine different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, K+, Mg2+ and Ca2+) for PM10 particles and ten different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, NH4 +, K+, Mg2+ and Ca2+) for PM2.5 particles. The source apportionment study of PM10 and PM2.5 for urban Mangalore in accordance with these six sample sites using chemical mass balance model (CMBv8.2) revealed nine and twelve predominant contributors for both PM10 and PM2.5, respectively. The highest contributor of PM10 was found to be paved road dust followed by diesel and gasoline vehicle emissions. Correspondingly, PM2.5 was found to be contributed mainly from two-wheeler vehicle emissions followed by four-wheeler and heavy vehicle emissions (diesel vehicles). The current study depicts that the PM10 and PM2.5 in ambient air of Mangalore region has 70% of its contribution from vehicular emissions (both exhaust and non-exhaust). © 2018 Elsevier LtdItem Investigation on thermodynamic performance analysis and environmental effects of various new refrigerants used in air conditioners(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Vali, S.V.; Saboor, S.; Gorantla, K.; Mahapatra, D.; Setty, A.B.T.P.The main aim of this present investigation is to evaluate performance and environmental impact analysis of various novel mixture refrigerants as R22 replacements theoretically. Refrigerants with lower global warming potential (GWP) can be adequate for bringing down emissions which are concerned for air conditioners. In this investigation, twenty-seven refrigerants were developed at several compositions. Important studies such as computation of CO2 emissions using total equivalent warming impact (TEWI), toxicity and flammability analysis of various considered refrigerants were also carried out in this investigation. Performance analysis of refrigerants was conducted under different operating conditions. Results showed that the energy efficiency ratios (EERs) of refrigerants such as R1270, RM30 (R152a/R1270/RE170 of 25/71/4 by mass percentage) and RM50 (R152a/R1270/RE170 of 10/85/5 by mass percentage) were closer to that of R22 and they are relatively lower than R22 by 0.95%, 1.34% and 1.80%, respectively. Toxicity investigation exhibited that all the refrigerants studied were classified into nontoxic category (A) whereas flammability investigation revealed that all the novel refrigerant mixtures (RM10 to RM50) were classified into flammable category (A3). CO2 emissions (TEWI) released from air conditioner working with R1270, RM30 and RM50 were 7.41%, 6.85% and 6.51%, respectively, lower than that of R22. In terms of several thermodynamic aspects, the performance of refrigerants such as R1270, RM30 and RM50 were superior to those of R22 and its various considered alternatives working under different operating conditions, although their EERs are fairly lower than R22 and hence, these refrigerants could be considered suitable environment-friendly alternatives to R22 used in air conditioners. The present study gives essential information and a road map towards the development of low GWP R22 alternative refrigerant blends from the viewpoint of toxicity, flammability, performance aspects, environmental and safety aspects, respectively. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Particulate matter (PM10) enhances RNA virus infection through modulation of innate immune responses(Elsevier Ltd, 2020) Mishra, R.; Krishnamoorthy, P.; Gangamma, S.; Raut, A.A.; Kumar, H.Particulate matter (PM10) enhances severity of influenza virus infection through skewing innate immunity via modulation of metabolic pathways-related genes.; Sensing of pathogens by specialized receptors is the hallmark of the innate immunity. Innate immune response also mounts a defense response against various allergens and pollutants including particulate matter present in the atmosphere. Air pollution has been included as the top threat to global health declared by WHO which aims to cover more than three billion people against health emergencies from 2019 to 2023. Particulate matter (PM), one of the major components of air pollution, is a significant risk factor for many human diseases and its adverse effects include morbidity and premature deaths throughout the world. Several clinical and epidemiological studies have identified a key link between the PM existence and the prevalence of respiratory and inflammatory disorders. However, the underlying molecular mechanism is not well understood. Here, we investigated the influence of air pollutant, PM10 (particles with aerodynamic diameter less than 10 ?m) during RNA virus infections using Highly Pathogenic Avian Influenza (HPAI) – H5N1 virus. We thus characterized the transcriptomic profile of lung epithelial cell line, A549 treated with PM10 prior to H5N1infection, which is known to cause severe lung damage and respiratory disease. We found that PM10 enhances vulnerability (by cellular damage) and regulates virus infectivity to enhance overall pathogenic burden in the lung cells. Additionally, the transcriptomic profile highlights the connection of host factors related to various metabolic pathways and immune responses which were dysregulated during virus infection. Collectively, our findings suggest a strong link between the prevalence of respiratory illness and its association with the air quality. © 2020 Elsevier Ltd; © 2020 Elsevier LtdItem Assimilative capacity approach for air pollution control in automotive engines through magnetic field-assisted combustion of hydrocarbons(Springer Science and Business Media Deutschland GmbH, 2021) Oommen, L.P.; Gottekere Narayanappa, K.G.Deterioration of air quality through the combustion of hydrocarbon fuels has been one of the global transboundary problems put before the research community since last five decades. According to the updated statistics, 79% of energy needs in India are met by fossil fuel combustion which results in the emission of toxic pollutants like carbon monoxide, oxides of nitrogen, and unburned hydrocarbons. Air quality has seriously been affected in many parts of India, and statistically, 13 out of 15 most polluted cities in the world lie in India. Magnetic field-assisted combustion has been proven as a reliable technology in internal combustion engines for enhancing the combustion of fuels and reduction of harmful emissions that are the byproducts of incomplete combustion of fuels. In the present work, the magnetic field-assisted combustion of a liquid-phase and a gas-phase fuel (gasoline and LPG) has been studied in a multicylinder automobile engine replicating on road driving conditions in a laboratory focusing on the levels of emissions in comparison with normal combustion of both the fuels. The experimental study concludes that the applied magnetic field positively influences combustion, resulting in reduced level of emission of toxic components irrespective of the phase of hydrocarbon fuels. It is also observed that the percentage reduction in emissions increases with increase in intensity of magnetization. The maximum reduction obtained for CO and UBHC emissions through this technique is 20.58% and 14.47%, respectively. The effectiveness of MFAC in countering air pollution from vehicular exhaust is also studied with respect to fuel phase and mode of operation. The effectiveness of MFAC is observed to be more in high-speed operation of the engine and decreases in the order CO > UBHC > NO. The obtained emission results have a cumulative significance as 45% of total air pollution in India is caused by combustion of hydrocarbons in automotive engines. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.