Faculty Publications
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Item Impact of Aquaculture Solid Waste on Environment in the Delta Region of Andhra Pradesh: A Case Study(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.Aquaculture solid waste (ASW) from the aquaculture ponds is emerging waste which impacts on the environment due to intensive culture practices. In intensive aquaculture ponds, 45–65% of the dry weight of waste (shells, fins, and bones), surplus feed, chemicals, and minerals. This has led to a decline in the quality of the water used for aquaculture, environmental pollution, the occurrence of aquatic diseases, and even ecological imbalance, which has become a significant concern. This study presents the leachate characteristics and groundwater characteristics of the nearby dump sites. Field surveys were carried to know the source and disposal of ASW and to identify the lacunae of practice. Based on the leachate characteristics, it has been suggested that proper management of ASW is needed. This study also explores the Indian ASW and its impact on environment. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of Nitrate Fluxes in Intensive Aquaculture Region in Godavari Delta Using Spatial Interpolation Kriging(Springer Science and Business Media Deutschland GmbH, 2024) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.; Rambabu, T.In areas with a high concentration of intense aquaculture, nitrate pollution and nutrient enrichment are growing concerns. With predicted future climate changes, these problems are expected to intensify for aquifers and surface waters. The possibility exists to reduce some of these worries through land management and utilization modifications. However, there is much ambiguity surrounding how these alterations will relate. This article uses conventional kriging and empirical Bayesian kriging (EBK) to estimate nitrate levels in India’s intensive aquaculture zone, the Godavari delta. The stable, exponential, rational quadratic, and Gaussian models were used to fit experimental variograms using weighted least squares. The number of neighbors that generated the best cross-validation outcome has been further investigated for the model with the shortest residual sum of the squares. Kriging’s statistical approaches provided the best root mean square error (RMSE) values overall. No additional summary statistics shed any light on the regression method’s selection or settings. After thorough testing, we concluded that many parameters might be better detected using cross-validation. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Prediction of Inland Aquaculture Ammonia Using Hybrid Intelligent Soft Computing(Springer Science and Business Media Deutschland GmbH, 2024) Thotakura, T.V.; Bala, G.; Durga Prasad, C.; Sunil, B.M.One of the crucial factors in assessing the pond's intensive inland aquaculture water quality condition is ammonia. The excessive ammonia content will likely worsen water quality and result in the mass mortality of cultured individuals. For aquaculture management, it is therefore vital to accurately identify the ammonia nitrogen level of cultured water. However, the accuracy of technology for monitoring the ammonia content of aquaculture water currently needs to be improved to satisfy the demands of intensive aquaculture. This paper presents the prediction of the ammonia concentration of aquaculture water in real time using a hybrid intelligent soft computing algorithm. Radial basis function neural networks (RBFNN) and a hybrid model combining RBFNN, and particle swarm optimization (PSO) are used in this technique. Root mean square error (RMSE) and correlation coefficient (R2) were two separate statistical metrics used to compare the two methodologies and assess how well the soft computing strategies performed. The ammonia prediction results showed that the PSO-RBFNN method outperformed the RBFNN. The PSO-RBFNN model offers a real-time ammonia prediction value in inland farming waters that is moderately and generally accurate. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Multivariate Statistical Approach for Assessment of Surface Water Quality in the Intensive Inland Aquaculture Region in India(Springer Science and Business Media Deutschland GmbH, 2024) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.; Bala, G.Andhra Pradesh's western Godavari Delta region is India's primary inland aquaculture zone, with a well-developed canal network. The Venkaya-Vayyeru canal is the most important canal stream depending on aquaculture catchment. It also serves as a drinking water supply for villages, aquaculture, and irrigation. As a result, the quality of the canal's water is essential. To determine the probable location as a pollution source, this study considered eight physicochemical water quality characteristics at three distinctive places along the canal for principal component analysis (PCA). Most parameters show significant geographical variation, indicating anthropogenic influence. According to PCA findings, the principal pollution sources are aquaculture ponds, processing businesses, and urban activities. Aquaculture intensively may contaminate canal water with salinity, ammonia, and Ca2+. Aquaculture effluents, soluble salts, nutrients, and organic matter were found to be the essential parameters responsible for changes in water quality using PCA and factor analysis. The study demonstrates the usefulness of multivariate statistical methods in understanding a pattern of feature variability and devising management techniques to enhance canal water quality by identifying prevailing characteristics that cause the most degradation in the water quality. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Thermodynamic simulation of ammonia-water absorption refrigeration system(Serbian Society of Heat Transfer Engineers, 2008) Sathyabhama, A.; Ashok Babu, T.P.The ammonia-water absorption refrigeration system is attracting increasing research interests, since the system can be powered by waste thermal energy, thus reducing demand on electricity supply. The development of this technology demands reliable and effective system simulations. In this work, a thermodynamic simulation of the cycle is carried out to investigate the effects of different operating variables on the performance of the cycle. A computer program in C language is written for the performance analysis of the cycle.Item Modelling for organics and nutrients release during benthal sludge stabilisation part il - Nutrients(2009) Bhargava, D.S.; Shrihari, S.Settleable solids from untreated or partially treated domestic and industrial effluents undergoing stabilisation in stream beds contain significant amount or nutrients such as ammonia and phosphates apart from carbonaceous organic material. An experimental investigation was carried out to study the contribution of biochemical oxygen demand (BOD) and nutrients by this benthal-sludge undergoing stabillisation in steam beds. Sludge was collected from a sewage channel and placed at the bottom of an experimental reactor, and a continuous flow of clean tap water was maintained, in such a manner that the sludge was not disturbed. The first part of this work contained a discussion on degreadation of carbonaceous matter. The degradation of the nutrients, such as ammonia and phosphates being released from the sediments into the overlying waters at different flow rates of over laying waters is evaluated. It was noticed that the ammonia and phosphates released from the sediments into the overlying waters become more or less uniform after some days. The ammonia release and phosphate release were found to be affected by changes in the flowrates of overlying waters. The ammonia and phosphates remaining in the top and bottom layers of the sediments also showed similar trends. Predictive models have been presented for the variation of ammonia and phophate release into the overlying water, ammonia and phosphates remaining in the sediment layers at different times and different flow rates.Item Experimental investigation in pool boiling heat transfer of ammonia/water mixture and heat transfer correlations(2011) Sathyabhama, A.; Ashok Babu, T.P.A.The nucleate pool boiling heat transfer coefficient of ammonia/water mixture was investigated on a cylindrical heated surface at low pressure of 4-8bar and at low mass fraction of 0NH3<0.3 and at different heat flux. The effect of mass fraction, heat flux and pressure on boiling heat transfer coefficient was studied. The results indicate that the heat transfer coefficient in the mixture decreases with increase in ammonia mass fraction, increases with increase in heat flux and pressure in the investigated range. The measured heat transfer coefficient was compared with existing correlations. The experimental data were predicted with an accuracy of ±20% by the correlation of Calus&Rice, correlation of Stephan-Koorner and Inoue-Monde correlation for ammonia/water mixture in the investigated range of low ammonia mass fraction. The empirical constant of the first two correlations is modified by fitting the correlation to the present experimental data. The modified Calus&Rice correlation predicts the present experimental data with an accuracy of ±18% and the modified Stephan-Koorner correlation with an accuracy of ±16%. © 2011 Elsevier Inc.Item Vapor-liquid equilibrium of ammonia-water-lithium nitrate solutions(2011) Sathyabhama, A.; Ashok Babu, T.P.Experimental results on the pressure-temperature data for the NH3-H2O binary and NH3-H2O-LiNO3 ternary solutions are reported. The pressure was varied between 100 and 800 kPa, while the mass fraction of ammonia was varied in the range 0-0.30. The lithium nitrate concentration of the solution was chosen in the range of 10-50% of mass ratio of lithium nitrate in pure water. An analytical equation for the equilibrium pressure as a function of temperature and concentration was obtained with a good fit to experimental data. © 2011 Wiley Periodicals, Inc.Item Experimental study of nucleate pool boiling heat transfer to ammonia-water-lithium bromide solution(2011) Sathyabhama, A.; Ashok Babu, T.P.Visualization of bubble nucleation during nucleate pool boiling outside a vertical cylindrical heated surface was done for ammonia-water binary and ammonia-water-lithium bromide ternary mixture in order to obtain a descriptive behavior of the boiling which was directly compared with the measured heat transfer coefficient at low pressure of 4-8. bar and at low ammonia mass fraction of 0Item Nucleate pool boiling heat transfer measurement and flow visualization for ammonia-water mixture(2011) Sathyabhama, A.; Ashok Babu, T.P.Visualization of bubble nucleation during nucleate pool boiling outside a vertical cylindrical heated surface was done for ammonia-water binary mixture in order to obtain a descriptive behavior of the boiling, which was directly compared with the measured heat transfer coefficient data at low pressure of 4-8 bar and at low mass fraction of 0 < x < 0.3 and at different heat flux. Still images taken with high speed camera are used to demonstrate the decrease in boiling heat transfer coefficient with increase in ammonia mass fraction. Jensen and Memmel model has better agreement with experimental bubble diameter. Further work is required to obtain quantitative information about bubble nucleation parameters. It is found that both Calus and Rice and Stephan-Koorner correlation can predict the experimental heat transfer coefficient values with a maximum deviation of ±20%. © 2011 American Society of Mechanical Engineers.