(SoE) School of Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

Aeroelastic systems with hardening nonlinearity exhibit supercritical Hopf bifurcation when the flow velocity exceeds a critical velocity leading to self-sustaining large amplitude limit cycle oscillations known as flutter. This study investigates the effects of irregular fluctuations in the flow on the dynamical stability characteristics of a two-degree-of-freedom pitch-plunge aeroelastic system with hardening nonlinearity. Dynamical or D-bifurcations are investigated through the computation of the largest Lyapunov exponent, while phenomenological or P-bifurcation analysis is carried out by examining the structure of the joint probability density function of the response quantities and their instantaneous time derivatives. The qualitative nature of P-bifurcation analysis makes it difficult to pinpoint the regimes of different response dynamics. In the light of this difficulty, a quantitative analysis using the Shannon entropy measure has been undertaken to quantify the P-bifurcation regime. This regime is shown to be coincident with the intermittency regime observed in the response time histories prior to flutter oscillations in fluctuating flows. © 2018, Springer Science+Business Media B.V., part of Springer Nature.

Mechanical Engineering

World University root node

Nonlinear Dynamics

Intermittency in pitch-plunge aeroelastic systems explained through stochastic bifurcations

In this work, we have added p-type and n-type Si nanoparticles (NPs) obtained from cryomilling, in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) organic photovoltaic cell at different weight ratios and their effect on organic-inorganic hybrid solar cell device parameters has been evaluated. It is observed that the addition of p-type nanoparticles tailors the energy band alignment at the P3HT/NP interface which provides efficient charge carrier transport enhancing the photo-conversion efficiency by more than 21%. Enhancement is reflected by an improvement in short-circuit current by ∼35% with respect to reference P3HT:PC61BM device without Si NPs. However, for n-type NPs where the optimum cascading band alignment does not occur, only 10% improvement in photo-conversion efficiency is observed. This work provides insight into how the performance of organic solar cells can be tailored by size factor as well as byenergy level tuning of the added nanoparticles. © 2018

Electrical Engineering

Solar Energy

Doped silicon nanoparticles for enhanced charge transportation in organic-inorganic hybrid solar cells

This paper presents a new approach to physical relocation of photovoltaic (PV) modules in Totally Cross Tied (TCT) configuration of an array without altering the electrical connection. This proposed arrangement is a one time arrangement at the time of installation and this arrangement ensures for the enhancement of power generation of the PV array under partial shading conditions. In this arrangement, the shading effects are distributed over the entire array and hence reduce the multiple peaks in the power-voltage characteristics. The power generated by the proposed arrangement of a PV array is compared with the TCT configuration under different shading patterns. Also, the mismatch loss in the proposed configuration is compared with existing configurations under different shading patterns. © 2018 IEEE.

ITEC Asia-Pacific 2018 - 2018 IEEE Transportation Electrification Conference and Expo, Asia-Pacific: E-Mobility: A Journey from Now and Beyond

Maximum Power Output from a Solar PV Array under Partially Shaded Conditions

The paper presents the development of a new device for measuring continuous pulse pressure waveforms (PPW) from the radial artery via applanation tonometry. The development focuses on improved accuracy, open and affordable design using off-the-shelf components, and greater user control in setting operational and calibration parameters to address user variability. The device design parameters are optimized through a tissue device interaction study based on a computational model. The design incorporates modular components and includes a sensor module for arterial flattening and pressure pickup, a differential screw mechanism and a related algorithm for controlled stepwise motion and data collection during flattening, and a brace for wrist-flexion adjustment. Maximum pulse amplitude (PA) was used as an indicator of the optimum level of arterial flattening for recording the PPW. The PPW was observed to distort due to changes in parameters like gel-head placement, hold-down pressure (HDP), and wrist extension. The pressure waveforms collected using the device were validated using limited data against established products and showed good correlation within 61.96 standard deviation of the mean difference in a Bland-Altman plot. This paper thus details the development of a simple and validated mechanical design to measure PPW using arterial tonometry. © 2018 by ASME.

Journal of Medical Devices, Transactions of the ASME

A novel modular tonometry-based device to measure pulse pressure waveforms in radial artery

The rising energy demand and climate change issues have warranted the inclusion of renewable energy resources with existing conventional fuel based generation system. The intermittent renewable generation require adequate battery support in order to minimize load deficit issues in electrical grid. Hence, an attempt has been made in this paper to formulate a short term deterministic Unit Commitment problem in renewable integrated environment with battery storage. Ten thermal generators are scheduled with a 500 MW wind energy generation system supported by 200 MWh battery with backup of four hours. A three stage solution methodology is evolved involving hybrid Particle Swarm Optimization (PSO) technique to provide techno-economic solution to this complex optimization problem. The charge/ discharge scheduling of battery energy storage integrated to wind generation system is taken up as a co-optimization problem. The generation of battery energy storage integrated wind energy system is so scheduled that it relieves the costlier thermal generating units in the most economic manner. © 2018, International Journal of Renewable Energy Research.

International Journal of Renewable Energy Research

Optimized generation scheduling of thermal generators integrated to wind energy system with storage

Wireless Power Transfer System (WPTS) is gaining more attention across low power to high power applications. It is a convenient, safer, reliable, and user-friendly solution to wireless Electric Vehicle (EV) charger users. In WPTS, large air-gap between coils may cause high leakage of magnetic fields and it may also lower the coupling factor (k). In such systems, selection of coil structure and core configuration plays a key role to reduce the magnetic leakage. In this paper, a thorough mathematical analysis of various coil structures has been presented and observed the change in inductance from one coil structure to another. A finite element method is used in this paper to study the effect of coil structure on self-inductance, mutual inductance and coupling factor between the coils. This paper also provides the numerous core configurations, which have been added to WPTS and simulated to find its effect on power transfer efficiency between transmitter and receiver. The analysis on various coil-core configurations are performed for distinct air gaps between the transmitter and the receiver and found the supreme coil-core configuration to achieve the better coupling between them. © 2017 IEEE.

2017 IEEE Transportation Electrification Conference, ITEC-India 2017

A study on effect of coil structures and core configurations on parameters of wireless EV charging system

In this paper we present a novel analytical expression for the bit error rate under ON-OFF Keying (OOK) modulation for Free Space Optical Communication using α-μ distribution. We perform numerical comparison between the PDF, CDF and BER using α-μ and Gamma-Gamma distribution. The relative error between PDF and CDF of Gamma Gamma and α-μ demonstrates the viability of α-μ as a alternative to Gamma-Gamma distribution. © 2018 IEEE.

Computer Science and Engineering

2018 27th Wireless and Optical Communication Conference, WOCC 2018

Exact analytical BER expression in FSO using α-μ Distribution proposed as an approximation of gamma-gamma PDF

Tribo-corrosion is an issue of concern for marine and other fluid machinery. High entropy alloys (HEAs) represent a new category of materials possessing exceptional properties. We investigated the erosion-corrosion behavior of Al0.1CoCrFeNi HEA. For comparison, stainless steel SS316L is also evaluated. Results indicate that despite low hardness and yield strength, HEA exhibits high erosion-corrosion resistance compared to steel. The HEA also shows high pitting and passive potentials compared to steel. The superior erosion-corrosion resistance of HEA is due to high corrosion resistance, and work hardenability. The degradation mechanism investigated using SEM show ploughing as the primary material removal mode (MRM) for HEA at an oblique angle compared to micro-cutting for SS316L steel. At normal impingement, platelet mechanism is observed to be the dominant MRM. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Advanced Engineering Materials

High Entropy Alloys: Prospective Materials for Tribo-Corrosion Applications

A theoretical investigation is presented that characterizes the emerging sub-threshold membrane potential and inter-spike interval (ISI) distributions of an ensemble of IF neurons that group together and fire together. The squared-noise intensity σ2 of the ensemble of neurons is treated as a random variable to account for the electrophysiological variations across population of nearly identical neurons. Employing superstatistical framework, both ISI distribution and sub-threshold membrane potential distribution of neuronal ensemble are obtained in terms of generalized K-distribution. The resulting distributions exhibit asymptotic behavior akin to stretched exponential family. Extensive simulations of the underlying SDE with random σ2 are carried out. The results are found to be in excellent agreement with the analytical results. The analysis has been extended to cover the case corresponding to independent random fluctuations in drift in addition to random squared-noise intensity. The novelty of the proposed analytical investigation for the ensemble of IF neurons is that it yields closed form expressions of probability distributions in terms of generalized K-distribution. Based on a record of spiking activity of thousands of neurons, the findings of the proposed model are validated. The squared-noise intensity σ2 of identified neurons from the data is found to follow gamma distribution. The proposed generalized K-distribution is found to be in excellent agreement with that of empirically obtained ISI distribution of neuronal ensemble. © 2018 Elsevier B.V.

BioSystems

Characterizing ISI and sub-threshold membrane potential distributions: Ensemble of IF neurons with random squared-noise intensity

The tropical cyclones (TCs) are often associated with unprecedented heavy rainfall, and have a pronounced impact over East coast states of India. This study has done comprehensive investigation on contribution of two episodic TCs rainfall to the annual rainfall using satellite based rainfall estimates from TMPA-3B42 (daily product), and rainfall data from India Meteorological Department (IMD) observations. We analyzed both rainfall distribution and inundation extent induced by two episodic severe cyclonic events (Super–cyclone 1999 and Phailin 2013), and assessed their impacts on hydro-meteorological parameters and agricultural productivity. Our findings suggest that rainfall originated from two episodic TCs significantly contributed to the annual rainfall, accounting for about 5–25\% over the coastal districts of Odisha state. Howbeit, it was subjected to underestimation owing to rainfall biases of TMPA-3B42 during TCs, which was evident when it was compared with IMD measurements. Along the TCs track, intense rainfall followed by peak discharge from the river basins caused substantial flooding and inundation of croplands over the coastal regions. The TC related rainfall, strong winds, and storm surges have diminished kharif season's agricultural production, as crops were submerged during these periods. Overall, the rice production has been diminished by 57\%, and this rice production even lowered by more than 70\% in some of the districts. Most severely affected districts (Ganjam, Puri, Cuttack, Jajpur, Bhadrak, Baleshwar) were located close to landfall, where croplands are dominating land use type. These results inferred that the isolated severe TCs could bring significant amount of rainfall, which would cause widespread impacts on agricultural activities. Finally, the findings of this unique study recommends that the satellite based rainfall estimate data can act as a valuable input for flood modeling and crop monitoring at different scales to alleviate hydro–meteorological and agricultural impacts. © 2018 Elsevier B.V.

Civil Engineering

Remote Sensing Applications: Society and Environment

Investigating the effects of episodic Super-cyclone 1999 and Phailin 2013 on hydro-meteorological parameters and agriculture: An application of remote sensing