| 1. |
- Joshi, Bhupendra, et al.
(författare)
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A comparative survey between cascade correlation neural network (CCNN) and feedforward neural network (FFNN) machine learning models for forecasting suspended sediment concentration
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Suspended sediment concentration prediction is critical for the design of reservoirs, dams, rivers ecosystems, various operations of aquatic resource structure, environmental safety, and water management. In this study, two different machine models, namely the cascade correlation neural network (CCNN) and feedforward neural network (FFNN) were applied to predict daily-suspended sediment concentration (SSC) at Simga and Jondhara stations in Sheonath basin, India. Daily-suspended sediment concentration and discharge data from 2010 to 2015 were collected and used to develop the model to predict suspended sediment concentration. The developed models were evaluated using statistical indices like Nash and Sutcliffe efficiency coefficient (NES), root mean square error (RMSE), Willmott’s index of agreement (WI), and Legates–McCabe’s index (LM), supplemented by a scatter plot, density plots, histograms and Taylor diagram for graphical representation. The developed model was evaluated and compared with CCNN and FFNN. Nine input combinations were explored using different lag-times for discharge (Qt-n) and suspended sediment concentration (St-n) as input variables, with the current suspended sediment concentration as the desired output, to develop CCNN and FFNN models. The CCNN4 model with 4 lagged inputs (St-1, St-2, St-3, St-4) outperformed the other developed models with the lowest RMSE = 95.02 mg/l and the highest NES = 0.0.662, WI = 0.890 and LM = 0.668 for the Jondhara Station while the same CCNN4 model secure as the best with the lowest RMSE = 53.71 mg/l and the highest NES = 0.785, WI = 0.936 and LM = 0.788 for the Simga Station. The result shows the CCNN model was better than the FFNN model for predicting daily-suspended sediment at both stations in the Sheonath basin, India. Overall, CCNN showed better forecasting potential for suspended sediment concentration compared to FFNN at both stations, demonstrating their applicability for hydrological forecasting with complex relationships.
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| 2. |
- Kumar, Advitiya, et al.
(författare)
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Emulsion templated cellulosic porous scaffolds of superior oleophilicity
- 2023
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Ingår i: Cellulose. - : Springer Nature. - 0969-0239 .- 1572-882X. ; 30:14, s. 9047-9059
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Tidskriftsartikel (refereegranskat)abstract
- Oil spills and related environmental concerns have been dealt using various approaches including hydrophobic absorbents made of synthetic polymers. Disposal and secondary contamination from such polymeric absorbent however are issues due to non-degradable nature of synthetic polymers. A cellulose based oleophilic porous scaffold for oil sorption is thus fabricated in this work via emulsion templating. Pre-treated wood pulp cellulose based high internal phase emulsion was developed through judicious choice of solvent, emulsifiers, nature and volume fraction of dispersed phase, and crosslinker for cellulose. The scaffold showed a highly interconnected porous structure resulting in an oil sorption capacity up to 8.8 g/g for automobile engine oil (volumetric swelling of 30 ml/ml), matching with some of the previously reported hydrophobically modified cellulosic absorbents. The scaffold showed no structural disintegration or decline in sorption capacity during cyclic sorption-desorption test up to 5 cycles. The oleophilic character was introduced in the scaffold due to high surface area and interconnected macropores acting as microchannels and reservoir for oil sorption without any interaction of the hydrophilic cellulose with the oil. The efficiency of porous scaffold of a natural polymer for oil sorption can further be enhanced via hydrophobic functionalization and other vast applications.
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| 3. |
- Rai, Sanskriti, et al.
(författare)
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Circulating plasma miR-23b-3p as a biomarker target for idiopathic Parkinson's disease: comparison with small extracellular vesicle miRNA
- 2023
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media S.A.. - 1662-4548 .- 1662-453X. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: Parkinson's disease (PD) is an increasingly common neurodegenerative condition, which causes movement dysfunction and a broad range of non-motor symptoms. There is no molecular or biochemical diagnosis test for PD. The miRNAs are a class of small non-coding RNAs and are extensively studied owing to their altered expression in pathological states and facile harvesting and analysis techniques.Methods: A total of 48 samples (16 each of PD, aged-matched, and young controls) were recruited. The small extracellular vesicles (sEVs) were isolated and validated using Western blot, transmission electron microscope, and nanoparticle tracking analysis. Small RNA isolation, library preparation, and small RNA sequencing followed by differential expression and targeted prediction of miRNA were performed. The real-time PCR was performed with the targeted miRNA on PD, age-matched, and young healthy control of plasma and plasma-derived sEVs to demonstrate their potential as a diagnostic biomarker.Results: In RNA sequencing, we identified 14.89% upregulated (fold change 1.11 to 11.04, p < 0.05) and 16.54% downregulated (fold change −1.04 to −7.28, p < 0.05) miRNAs in PD and controls. Four differentially expressed miRNAs (miR-23b-3p, miR-29a-3p, miR-19b-3p, and miR-150-3p) were selected. The expression of miR-23b-3p was “upregulated” (p = 0.002) in plasma, whereas “downregulated” (p = 0.0284) in plasma-derived sEVs in PD than age-matched controls. The ROC analysis of miR-23b-3p revealed better AUC values in plasma (AUC = 0.8086, p = 0.0029) and plasma-derived sEVs (AUC = 0.7278, p = 0.0483) of PD and age-matched controls.Conclusion: We observed an opposite expression profile of miR-23b-3p in PD and age-matched healthy control in plasma and plasma-derived sEV fractions, where the expression of miR-23b-3p is increased in PD plasma while decreased in plasma-derived sEV fractions. We further observed the different miR-23b-3p expression profiles in young and age-matched healthy control.
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| 4. |
- Khullar, Subodh, et al.
(författare)
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Influence of the runner cone design on the pressure fluctuations in the draft tube of a low head Francis turbine
- 2021
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Ingår i: OP Conference Series: Earth and Environmental Science. - : Institute of Physics (IOP). - 1755-1307.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a preliminary numerical investigation on the design of the runner cone for a small turbine test rig under development at IIT Roorkee, India. The test rig is designed to study the formation and mitigation of rotating vortex rope (RVR) in the draft tube of a low head Francis turbine. The original runner cone design needs to be modified to include the provision for axial jet injection. Three different configurations, namely, a truncated cone and two original length cones with different nozzle positions, have been compared with the original cone to choose a suitable one for further investigations. The entire three-dimensional flow passage of the turbine unit has been simulated using the shear stress transport turbulence model after carrying out a mesh independence test on the original design. The proposed designs are compared at three different operating points. The amplitude and frequency of the pressure pulsations in the draft tube have been analyzed using the fast Fourier transform (FFT) method.
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| 5. |
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| 6. |
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| 7. |
- Kumar, Sandeep, et al.
(författare)
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Repeatability in Measurements and Control Settings of a Small Francis Turbine Test Rig
- 2024
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Ingår i: Journal of Verification, Validation and Uncertainty Quantification. - : American Society of Mechanical Engineers (ASME). - 2377-2158 .- 2377-2166. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- A reduced scaled-down hydraulic turbine test setup has been designed. The test setup is made to investigate the mitigation of pressure pulsations like the rotating vortex rope (RVR) and its formation and problems related to prototype operation. The setup arrangements and instrumentations follow mostly the International Electrotechnical Commission (IEC) standards. This paper presents the runner hub modification, calibration procedure, repeatability and systematic uncertainty estimation, and measurement methods per the guidelines in IEC 60193 and IEC 60041. The calibration and regression errors of all instruments are presented. A LABVIEW program for open-loop operation at a constant head and closed-loop operation at constant discharge is also presented. Finally, the systematic and random uncertainty of hydraulic efficiency is discussed.
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| 8. |
- Kumar, Sandeep, et al.
(författare)
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Retracted: Repeatability in measurements and control settings of a small francis turbine test rig
- 2022
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Ingår i: Flow Measurement and Instrumentation. - : Elsevier. - 0955-5986 .- 1873-6998. ; 88
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Tidskriftsartikel (refereegranskat)abstract
- A reduced scaled-down hydraulic turbine test setup has been designed. The test setup is made to investigate the mitigation of pressure pulsations like the rotating vortex rope (RVR) and its formation and problems related to prototype operation. The setup arrangements and instrumentations follow mostly the international electro-technical commission (IEC) standards. This paper presents the runner hub modification, calibration procedure, repeatability and systematic uncertainty estimation, and measurement methods as per the guidelines given in IEC 60193 and IEC 60041. The calibration and regression curves of all devices are presented. A LABVIEW program for open-loop operation at a constant head and closed-loop operation at constant discharge is also presented. Finally, the systematic and random uncertainty of hydraulic efficiency is discussed.
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| 9. |
- Kumar, Sandeep, et al.
(författare)
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Rotating vortex rope formation and mitigation in draft tube of hydro turbines – A review from experimental perspective
- 2021
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 136
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Forskningsöversikt (refereegranskat)abstract
- Hydropower is a clean and renewable source of energy which is widely used to generate electric power and stabilize the power grid. It can respond quickly to any change in demand with the flexibility to operate over a wide range of time scales. At steady-state part-load operation, a flow structure known as precessing vortex rope develops in the draft tube of singly regulated reaction turbines, which causes large pressure pulsations. The vortex rope develops pressure pulsations in the draft tube cone, structural vibrations, power swings, pulsative pressure recovery, which are the main concerns in the hydropower sector. Studies were carried out to understand the inception as well as mitigation of these detrimental effects due to the rotating vortex rope (RVR) development. The primary focus of the present study is to comprehensively review the experimental investigations carried out to study the formation of RVR, its effects on turbine performance, and the methodologies developed to mitigate its impact.
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