Faculty Publications
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Item Agent-based approach for the management of dynamic QoS violations in the inter-cloud environments(Springer Verlag service@springer.de, 2018) Thomas, M.V.; Chandrasekaran, K.; Mugeraya, G.Nowadays, considerable attention has been given by the researchers in the field of Cloud Computing to the emerging Inter-Cloud computing paradigm, where different cloud service providers collaborate or federate to achieve better QoS and cost efficiency. In this context, in order to prevent the unauthorized access of the distributed system components, authentication and authorization functions are to be enforced effectively. In this paper, we propose the conceptual model of the agent-based approach for the identity and access management in the dynamic inter-cloud environments where the Cloud Service Providers or the partners of the inter-cloud federation join and leave the federation dynamically. We further discuss the architectural model for the agent-based approach for solving the policy conflicts in the inter-cloud scenario while dealing with the access requests of cloud consumers in the inter-cloud environments. A few open issues in the area of identity and access management in the inter-cloud environment are also discussed. © 2018, Springer Nature Switzerland AG.Item Halophilic bacteria and their compatible solutes -osmoregulation and potential applications(2011) Shivanand, P.; Mugeraya, G.Halophilic bacteria grow over an extended range of salt concentrations. Their metabolic patterns are distinct compared to their terrestrial counterparts and obligate halophiles. The possibility of rapid adjustment to changes in the external salt concentration makes them potential candidates for bioprocessing. Halophilic bacteria produce enzymes, metabolites, solutes, exopolysaccharides and pigments which have high commercial value. However, compared to the obligate halophilic archaea, they have been less studied with only a few reports available on designing the production processes. Compatible solutes are the highly soluble, low-molecular weight organic compounds that make halophilic bacteria versatile in their adaptation to salinity. Halophilic bacteria either take in the solutes from the medium or synthesize them de novo. Compatible solutes include amino acids, carbohydrates or their derivatives, sugars and polyols. In addition to their stabilizing effects, they offer a multitude of physiological and potential biotechnological applications ranging from stabilizers of biomolecules, stress-protective agents to therapeutic agents and cosmetic actives. Exploring the significant applications of compatible solutes could be an attractive proposition towards commercialization. Moreover, it would enlighten the bases of adaptations of moderately halophilic bacteria.Item Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India(2006) Balakrishna, K.; Kumar, I.A.; Srinikethan, G.; Mugeraya, G.Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO2 emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. © Springer Science+Business Media, Inc. 2006.Item Characterization of the MSW leachate at Mangalore dump yard, India(2006) Ravishankar, R.; Madhuri, B.; Mugeraya, G.In India, solid waste generation is about 1,00,000 MT per day, of which over 90% is land filled. Landfills are nothing but dump yards without top and bottom impermeable layers. All types of wastes viz., Hazardous, Industrial and even biomedical waste are dumped in these yards. Municipal agencies, responsible for handling wastes, are constructing engineered land fills wherever additional land is available as per MSW (Handling & Management) Rules 2000. The rule stipulates the same limits for leachate discharge as that of industrial wastes. But the characteristics of leachate are not available with the authorities to decide on the system of treatment process. As new landfills are being constructed it is very essential to have a data on the MSW leachate characteristics for deciding on the best treatment method. Therefore in this study the characteristics of the leachate generating from Mangalore MSW landfill was studied during July 2004 to November 2004. pH of the leachate is on the basic side with the value around 8.1±0.2. There is no much variation in the temperature as it was 27°C during July'04 and increased only by 2°C to 29.2°C. towards the end of the study period. Total solids initially decreased from 12800 mg/L to 10300 mg/L due to post monsoon season and as the rainwater dilution decreases, the value of solids increased to 14530 ppm. Total dissolved solids gradually increased from 6700ppm to 10,530 ppm, which is very high compared to standards (2100 ppm). BOD and COD values gradually increased from 200 to 1200 ppm and 2000 to 7200 ppm respectively. This gradual increase can be attributed to the decreased amount of infiltration. These values are much higher than the stipulated standards. Copyright © Enviromedia.Item Isolation of Thiobacillus sp from aerobic sludge of distillery and dairy effluent treatment plants and its sulfide oxidation activity at different concentrations(Triveni Enterprises, 2007) Ravichandra, P.; Mugeraya, G.; Rao, A.G.; Ramakrishna, M.; Jetty, A.In the present study two strains of Thiobacillus sp were isolated from aerobic sludge of distillery and dairy effluent treatment plant using standard methods of isolation and enrichment. Experiments were conducted using isolated cultures in batch bioreactor with initial sulfide concentration of 75 and 150 mg/l. The effect of initial sulfide concentration on the activity of isolated Thiobacillus sp was studied. Sulfide oxidizing capacity was also determined at different initial sulfide concentrations. The results from the study indicate the possible isolation of Thiobacillus cultures from native source and application in the full-scale reactor. © Triveni Enterprises.Item Continuous operation of fluidized bed bioreactor for biogenic sulfide oxidation using immobilized cells of Thiobacillus sp(Asian Network for Scientific Information, 2007) Ravichandra, P.; Mugeraya, G.; Anupoju, G.R.; Ramakrishna, M.; Jetty, A.In the present study, obligate autotrophic Thiobacillus sp. was isolated from aerobic sludge distillery effluent treatment plant and the experiments were conducted in a fluidized bed bioreactor for the biological oxidation of sulfide using Ca-alginate immobilized Thiobacillus sp. All the experiments were conducted in continuous mode at different sulfide loading rates 0.018, 0.02475, 0.03375, 0.03825 and 0.054 and different hydraulic retention times 5, 3.67, 2.67, 2.35 and 1.67 h by varying flow rates 2.4×10-4, 3.3×10-4, 4.5×10-4, 5.1 × 10-4 and 7.2×10-4. Sulfide conversions higher than 90% were obtained at almost all sulfide loading rates and hydraulic retention times. All the experiments were conducted at constant pH of around 6 and temperature of 30±5°C. © 2007 Asian Network for Scientific Information.Item Spatial and temporal variations in water quality, major ions and trace metals(2007) Deepa, V.J.; Balakrishna, K.; Mugeraya, G.; Srinkethan, G.; Krishnakumar, P.K.Godavari river at Rajahmundry is monitored for a period of seven months at five stations along its course for the physicochemical parameters, major ions and trace metals. This study is made to obtain a baseline data of the existing pollutants in this 'hotspot', which is set to become the industrial hub of Andhra Pradesh. Results indicate that A P Paper Mills may not be polluting the river at this period, contrary to what was expected. Clear picture will emerge, once the data for the rainy season is available. Local pollution from detergents and soap in the river is seen in the downstream (station VIP) as lot of bathing and washing activity is done on the banks. There is no pollution of Cu, Ni, Pb, As and Co in the Godavari river at Rajahmundry. In general the pollutant levels in all the stations analysed is within the prescribed limits set by BIS and WHO standards. Copyright © Enviromedia.Item Biological treatment of toxic petroleum spent caustic in fluidized bed bioreactor using immobilized cells of thiobacillus RAI01(2008) Potumarthi, R.; Mugeraya, G.; Jetty, A.In the present studies, newly isolated Thiobacillus sp was used for the treatment of synthetic spent sulfide caustic in a laboratory-scale fluidized bed bioreactor. The sulfide oxidation was tested using Ca-alginate immobilized Thiobacillus sp. Initially, response surface methodology was applied for the optimization of four parameters to check the sulfide oxidation efficiency in batch mode. Further, reactor was operated in continuous mode for 51 days at different sulfide loading rates and retention times to test the sulfide oxidation and sulfate and thiosulfate formation. Sulfide conversions in the range of 90-98% were obtained at almost all sulfide loading rates and hydraulic retention times. However, increased loading rates resulted in lower sulfide oxidation capacity. All the experiments were conducted at constant pH of around 6 and temperature of 30?±?5 °C. © 2008 Humana Press.Item Hydrogen Sulfide Removal in Biofilter: Evaluation of a new filter material by immobilization of thiobacillus sp(Walter de Gruyter GmbH peter.golla@degruyter.com, 2009) Potumarthi, R.; Anupoju, G.R.; Mugeraya, G.; Jetty, A.Different agricultural residue was evaluated as a biofilter material for the removal of Hydrogen sulfide (H2S) using Thiobacillus sp. A Combination of four different agricultural residues, viz., sugarcane bagasse, coconut coir pith, rice husk and saw dust were evaluated as biofilter material. From results, it was observed that filter material having composition of 2:4:2:2, 4:4:2:2 and 4:2:2:4 has resulted in retaining 70% moisture content at the end of 10 days. The biofilter was operated for 128 days in three phases by varying inlet H2S concentration from 321 to 2020 ppmv. Biofilter exhibited 100% removal efficiency (RE) at an inlet concentration of 570 ppmv, 99% RE at an inlet concentration of 1416 ppmv and 66% RE at a maximum inlet concentration of 2020 ppmv. The filter performance in terms of RE, dropped to 48% when the air was not humidified before sending to the filter, which has direct relation with the MC of the filter material. The RE recovered to 66% with recovery of moisture content (MC) to 57% upon subsequent re-introduction of the humidifier in to the circuit. The pH has dropped from 7.8 to 4.8 during the course of operation of the filter. H2S was effectively removed under different operating conditions using mixed agricultural residue as filter material. However humidification was most essential to maintain the required moisture content in the biofilter. SEM analysis has shown the good growth of Thiobacillus sp. in the filter bed and hence the new material proved to be good support for the immobilization of Thiobacillus sp. Copyright © 2009 The Berkeley Electronic Press. All rights reserved.Item Screening and optimisation of bioconversion parameters for the reduction of 3-[5-[(4-flurophenyl)-1,5, di-oxopentol]-yl] -4-(S) phenyl oxazolidin-2-one(2009) Brahmani Priyadarshini, S.R.; Mugeraya, G.; Sandhyavali, M.S.The reduction of ketones is one of the most important and practical reaction for producing non racemic alcohols, which are needed to synthesize industrially important chemicals such as pharmaceuticals, agrochemicals and natural products. Biocatalysis has turned out to be a highly competitive technology for asymmetric ketone reduction. In the present work, an attempt was made to identify a potential microorganism for the reduction of 3-[5-[(4-flurophenyl)-1,5, di-oxopentol]-yl] -4-(S) phenyl oxazolidin-2-one. Some of the fungi screened were Saccharomyces cerevisiae, Aspergillus niger(2 strains), Pichia farinosa, Candida vishwanathii, Rhizopus stolonifer and Penicillin species. The experimental results showed that S. cerevisiae, Aspergillus niger and C. viswanathii strains were able to bring about the conversion of selected ketone to alcohol. As Saccharomyces cerevisiae was found to be more effective in bringing about reduction, it was selected for further experiment. In order to improve the yield certain bioconversion parameters like pH of reaction medium, time of incubation, incubation temperature and biomass to substrate ratio were studied. The results showed that the bioreduction of the above mentioned substrate was maximum in pH 7.6 at 30°C when incubated for 48 h. The conversion increased with increase in biomass, however it reached saturation at the ratio of 300:1.