http://hdl.handle.net/2080/17 Sun, 12 Jul 2026 13:51:33 GMT 2026-07-12T13:51:33Z http://hdl.handle.net/2080/5858 Title: Degradation of Chromium (VI) from Wastewater via Biological Route Using Inverse Fluidized Bed Reactor Authors: Mohanty, Rakesh; Gouda, Mitali; Nanda, Debasis; Mohapatra, Soumya Sanjeeb; Sahoo, Abanti Abstract: Background: In the present work, Cr (VI) has been degraded from wastewater by using an inverse fluidized bed reactor (IFBR) through biological route. Methodology: For the experimentation, a mixed type bacteria was cultured in the laboratory by using the bacteria present in the wastewater sample collected from mines. Initial hydrodynamic study was carried out using mine-water in IFBR containing poly-propylene beads up to certain bed height. The mixed bacteria culture was inoculated in IFBR for a particular concentration of synthetic wastewater. The experiments were performed at the minimum fluidization velocities for different concentrations of Cr(VI) varying from 1ppm to 10 ppm. The samples collected at different time intervals were analysed to measure the Cr(VI) concentration using UV-Spectrophotometer. Significant Findings: The minimum fluidization velocity for liquid medium and optimum air flow rate were determined as 0.0071 m/s and 0.042 m3/h respectively. The Cr(VI) degradation efficiency was found to be in the range of 98.9% to 99.3% for synthetic water sample and 77.6% for mine-water sample. Formation of bacteria layer on the surface of polypropylene beads was confirmed through confocal microscope. Various other characterizations like, SEM, EDX and FTIR were carried out by analysing bacteria samples before and after the experiments. The changes in morphology, elemental analysis and functional groups on the surface of bacteria before and after the experiments confirmed degradation of Cr (VI). The experimental results indicated the effectiveness of IFBR for removal of Cr (VI) from wastewater implying its suitability for removal of other heavy metals from industrial effluents in an eco-friendly manner. Description: Copyright belongs to proceeding publisher Mon, 01 Jun 2026 00:00:00 GMT http://hdl.handle.net/2080/5858 2026-06-01T00:00:00Z http://hdl.handle.net/2080/5857 Title: Investigation on Multiferroic Behavior of Brownmillerite Composite by Thermal and Magnetic Field Perturbation Authors: Sahoo, Durga Prasad; Mohanty, A; Palai, G; Mahapatra, C; Singh, A K Abstract: Our investigation on the auto combustion sol-gel synthesized (1 − x)KBiF e2O5 − (x)NiF e2O4 composite, where 0 ≤ x ≤ 1, has been performed through the tempera-ture, magnetic field, and frequency-dependent scientific methods. Rietveld refinement analysis with a proper χ2 value confirms the purity, phase formation, and lattice pa-rameters. The surface morphology shows a drastic change in grain size from in x=0.1 (1.48 ± 0.05 µm) to x=0.2 (0.77 ± 0.03 µm). The progressive addition of NFO ran-domizes the grain size and produces slight variations. In the x=0.2 composite, the 113% improved dielectric permittivity is (17.46×104) saw in composite. The 4 times enhanced MR (5.04±0.09 emu/g); however, the trivial variation in the HC (15%) of 182±3 Oe in x=0.4. The magnetic anisotropy of NFO is reflected in the LAS fitting, yielding a value of 5.52×104 erg/cm3 for the x=0.4 composite. Diffuse reflectance spectroscopy (DRS) and the Kubelka-Munk (KM) method figure out the direct band gap (n=2) of 1.74 eV for x=0.4 composite, suitable for photovoltaic applications. A maximum of 2.01% magnetodielectric (MD) coupling at 10 kHz is seen for the x=0.1 composite. Investigation suggests that a composite with high dielectric and moderate magnetization properties is suitable for low-magnetic-field-controlled data storage, sensor, and spintronic device applications. Description: Copyright belongs to the proceeding publisher Mon, 01 Jun 2026 00:00:00 GMT http://hdl.handle.net/2080/5857 2026-06-01T00:00:00Z http://hdl.handle.net/2080/5856 Title: Bifurcation Analysis of PLL-Based Grid-Following VSC for Robust Transient Synchronization Stability Authors: Singh, Amit Kumar; Maity, Somnath; Rudra, Shubhobrata; Aroudi, Abdelali El Abstract: The widespread integration of renewable energy sources with grid-following voltage source converters (VSCs) has introduced new challenges in synchronization stability of mod-ern power systems. Unlike synchronous generators in classical power systems, VSCs with a phase-locked loop (PLL) rely on grid voltage measurements for synchronization, making them particularly sensitive to significant grid disturbances. This paper investigates the transient synchronization stability of a PLL-based grid-following VSC subjected to symmetrical faults. A reduced-order generalized swing equation is used to analyze the dynamics of the PLL-based VSC system. Using bifurcation analysis, we examine here the existence and stability of the equilibria after faults and identify the critical fault-clearing conditions that can lead to the loss of synchronism. Moreover, time-domain simulations, validated against analytical predictions, demonstrate that symmetrical faults can cause rapid desynchronization and lead to system instability. Description: Copyright belongs to the proceeding publisher Mon, 01 Jun 2026 00:00:00 GMT http://hdl.handle.net/2080/5856 2026-06-01T00:00:00Z http://hdl.handle.net/2080/5855 Title: Design of a Sensorless Photovoltaic MPPT System Using PI-Observer Authors: Maity, Somnath; She, Jinhua Abstract: This paper aims to develop a two-loop modular pho-tovoltaic (PV) maximum power point tracking (MPPT) system that does not rely on any current sensors. The approach involves decomposing the PV system into two separate time scales: an open-loop system with a fast inner peak-current mode controller and a slower outer voltage control loop for MPPT operation. By applying this decomposition, we can accurately model the open-loop PVS by treating the duty-ratio dynamics as a state variable and reducing it to a second-order system. We also provide systematic design guidelines for the proportional-integral observer (PIO) for the PVS to achieve optimal performance in the presence of input disturbances and model uncertainties, and compare it with that of the classical P-observer. Description: Copyright belongs to the proceeding publisher Mon, 01 Jun 2026 00:00:00 GMT http://hdl.handle.net/2080/5855 2026-06-01T00:00:00Z