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Jayakumar N.,University of Malaya | Hashim M.A.,University of Malaya | Thomas M.T.,Institute of Science and Technology for Advanced Studies and Research ISTAR
Chemical Engineering and Technology | Year: 2010

Multiplicity analysis gives practical guidance for process design to eliminate difficult operating regions associated with input and output multiplicities. Continuous stirred tank reactors (CSTRs) present challenging operational problems due to complex behavior such as input and output multiplicities, ignition/extinction, parametric sensitivity, and nonlinear oscillations. In the absence of a unified mathematical theory for representing various nonlinear system characteristics, the present study was aimed at understanding the dynamic behavior of CSTRs by means of experiments and to link the experimental data to theoretical considerations for further detection and elimination of operating problems. Theoretical modeling and analysis of a non-isothermal CSTR with acid-catalyzed hydrolysis of an acetic anhydride system for input multiplicity are discussed. Theoretical modeling of a non-isothermal CSTR using a root-finding technique was carried out for predicting steady-state temperatures. Alternatively, a mathematical model for a non-isothermal CSTR using unsteady-state mass and energy balance equations is proposed. Computer-based simulation was carried out using a program developed in MATLAB for final transient temperature and time-temperature data of the CSTR system under investigation. The results of a theoretical analysis conducted for confirming the existence of input multiplicity in non-isothermal CSTRs with acid-catalyzed hydrolysis of acetic anhydride were compared with experimental investigations for validation. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Kumar J.I.N.,Institute of Science and Technology for Advanced Studies and Research ISTAR
Environmental Monitoring and Assessment | Year: 2013

The objective of the study is to reveal the seasonal variations in the river water and sediment quality with respect to heavy metal contamination. To get the extent of trace metals contamination, water and sediment samples were collected from five different sites along the course of Sabarmati River and its tributary Kharicut canal in pre-monsoon, monsoon and post-monsoon seasons. The concentration of trace metals such as chromium, copper, lead, nickel and zinc was determined using inductively coupled plasma spectroscopy. The concentrations of heavy metals were found to be higher in the pre-monsoon season than in the monsoon and post-monsoon seasons in water samples. The pollution load index, contamination factor and degree of contamination (C d) in sediments were calculated to know the extent of anthropogenic pressures. The values of C d clearly indicated very high degree of contamination at Kharicut canal (S-4: 32.25 and S-5: 54.52) and considerable degree of contamination at three sites of Sabarmati river viz; S-1, S-2 and S-3 with values 14.30, 14.42 and 17.21, respectively. Lead and nickel could not be traced in any of the river water samples. © 2012 Springer Science+Business Media B.V. Source


Chaubey N.K.,Institute of Science and Technology for Advanced Studies and Research ISTAR
International Journal of Security and its Applications | Year: 2016

Vehicular Ad-hoc Networks (VANETs) is a technology that has been recently emerged, and brings a lot of research interests. Security is one of the important issues in VANET, it is considered a critical point in the development of robust VANET applications. In this paper, various dimensions of VANETs including its emerging applications, security issues, challenges, security threats and the existing solutions proposed by the different researchers are studied. Also author reviewed various type of VANET simulator available and presented possible key research area of VANETs. © 2016 SERSC. Source


Verma S.,Institute of Science and Technology for Advanced Studies and Research ISTAR | De B.K.,Institute of Science and Technology for Advanced Studies and Research ISTAR
European Journal of Lipid Science and Technology | Year: 2010

The soil-derived fungus Emericella sp. was explored for its potential to produce lipid. Lipid profile, fatty acid composition, production of proteins and carbohydrates from lipid-extracted biomass were determined. The effects of variations in the contents of carbon sources (glucose, dextrose), the salt content (NaCl) and the growth period were studied. A study on the effect of different growing media on the abovementioned parameters was also carried out. Although the maximum amount of lipid (6.14 ± 0.42 g/L) and protein (5.99 ± 0.47 g/L) was produced after 13 days in medium A containing 10% wt/vol glucose, the optimum lipid (2.90 ± 0.21 g/L) and protein (3.23 ± 0.28 g/L) production was observed in 2% wt/vol glucose medium considering the glucose content in the medium. The principal fatty acids found were 16:0 (14.4 ± 1.0 to 24.5 ± 2.4 wt-%), 18:0 (12.1 ± 0.4 to 27.7 ± 2.7 wt-%), 18:1 (13.5 ± 2.1 to 25.2 ± 2.8wt-%) and 18:2 (30.9 ± 2.0 to 47.0 ± 2.8 wt-%). Some of the lipids, especially those grown for 7 days in less glucose-containing (1 and 2% wt/vol) medium were found to contain nearly 9.0 wt-% of long-chain PUFA 18:4, 20:4, 20:5, 22:4, and 22:5). © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


George B.,Institute of Science and Technology for Advanced Studies and Research ISTAR | Nirmal Kumar J.I.,Institute of Science and Technology for Advanced Studies and Research ISTAR
Egyptian Journal of Aquatic Research | Year: 2012

Physicochemical properties play a major role in determining the density, diversity and occurrence of phytoplankton in an estuarine ecosystem. The present study is conducted to assess the relationship between physicochemical parameters and phytoplankton assemblages which in turn can serve as a suitable method to assess the quality of estuarine ecosystem. Results showed an increased concentration in physicochemical parameters and phytoplankton density during post-monsoon season followed by pre-monsoon and monsoon season. Canonical correspondence Analysis (CCA) between environmental variables and dominant taxa of phytoplankton indicated the influence of freshwater on phytoplankton distribution in the estuarine precinct. © 2013 National Institute of Oceanography and Fisheries. Source

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