Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The electrocardiogram (ECG) signals represent the electrical activities of the heart. Noise and artifacts are inherent contaminating components of the ECG signal and denoising of these signals is quite an important issue, since the noise can hinder accurate diagnosis and detection of cardiac diseases. Also, automated noise detection and classification and selective removal of noises can play a vital role in the development of robust unsupervised ECG analysis systems. This paper mainly deals with the comparison of two different approaches for noise detection and classification of ECG signals. A unified framework is followed for noise detection and classification which consists of a signal decomposition method, short term temporal feature extraction and decision rules for detecting the noises. The two approaches for noise detection and classification only differ at the decomposition step, one uses the complete ensemble empirical mode decomposition and the other uses the wavelet packet decomposition. The decomposed signals are then analysed using certain short term temporal features for automatic detection, localization and classification of single and combined ECG noises. This framework is evaluated on MIT-BIH arrhythmia database and results for both the cases are compared. Results show that, the performance of wavelet based decomposition is comparable to CEEMD. This enables the proposed wavelet decomposition based approach to be an ideal candidate for real-time continuous monitoring systems such as ECG Holter monitors. © 2019 IEEE.

World University root node

Department of Electrical Engineering

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Automated Noise Detection and Classification for Unsupervised ECG Analysis Systems Using CEEMD and Wavelet Packet Decomposition

An event-based state estimation problem for a discrete-Time system when the measurements are corrupted with multiplicative noise is considered in this letter. A general event-based sampling is employed to obtain the measurements, where the event-based strategy is implicitly utilized to obtain state estimate and covariance. To deal with multiplicative noise, maximum a posteriori (MAP) estimator is used in conjunction with the Newton-Raphson iterative method. The proposed results are depicted using a numerical example. © 2017 IEEE.

IEEE Control Systems Letters

Event-based state estimation under the presence of multiplicative measurement noise

Photovoltaic (PV) system inverters have been frequently utilized for reactive power support in the literature. Although the benefits of PV reactive power for the grid have been quantified, the costs incurred by the PV owner have largely been ignored. This paper combines the findings from power electronics research and power system economics to formulate the cost of reactive power from PV inverters, considering the inverter degradation due to the reactive power provision. One-year simulations with real weather and load data for the case of Singapore for different levels of PV penetration have been conducted. Subsequently, the benefits of local reactive power provision to the system and its effect on the lifetime of PV inverters were analyzed. It was found that the cost of inverter lifetime reduction is a significant part of the reactive power cost (more than 50% at lower PV penetration), but decreases at higher PV penetration when the reactive power support is distributed over more PV systems. Through comprehensive analysis, the feasible range for monetary incentives for PV reactive power support has been identified. The results from this paper can, therefore, be used as a foundation for future research, formulating regulations, and for market analysis. © 2018 IEEE.

IEEE Transactions on Sustainable Energy

Reactive Power Cost From PV Inverters Considering Inverter Lifetime Assessment

Circulating current control is one of the critical issues in modular multilevel converters (MMCs). When a frequency-droop-regulated MMC is used to integrate an offshore wind farm into an high-voltage dc transmission system, the variation in its operating ac line frequency induces a change in circulating current harmonic frequencies. Hence, the conventional circulating current controllers, such as proportional-resonant or repetitive controller, which are tuned to a specific frequency, fail to alleviate the circulating current harmonics. In this paper, a new control architecture comprising of a spatial comb filter (SCF) and a spatial repetitive controller (SRC) is proposed to effectively attenuate the even-order harmonics in the circulating current independent of the operating ac line frequency of the MMC. The proposed controller incorporates the phase sampling technique to achieve the dynamic change in the sampling frequency, which is the key to strong periodic disturbance rejection capability of the SCF and SRC even under variable frequency operation. A system level simulation model has been developed on PLECS simulation software to demonstrate the performance of the proposed control architecture. In addition, a scaled-down laboratory prototype of a 1-kW, 400-V, five-level single-phase MMC is developed and the experimental results are presented to substantiate the performance of the proposed control scheme. © 1986-2012 IEEE.

IEEE Transactions on Power Electronics

A new control architecture with spatial comb filter and spatial repetitive controller for circulating current harmonics elimination in a droop-regulated modular multilevel converter for wind farm application

This paper has presented an extensive review of the bidirectional phase-modular and semi-modular Solid-State-Transformer (SST) topologies, specific to the matrix-type variants with single-stage AC-DC conversion. This includes a qualitative and mathematical explanation of each topology and the corresponding modulation(s). A comparative analysis incorporating the criteria of power density, failure rate, cost and component count is also done among all these topologies along with the conventional Cascaded-Modular-SST (CMSST) topology with two-stage AC-DC conversion. The matrix-based topologies clearly prove to be better than the CMSST topology in terms of power density and reliability, with the entirely phase-modular topologies proving to be superior overall. The AC-DC DAB type submodule has been estimated to have the best characteristics in terms of all the comparison indices and thus it can be considered to be the best among the grid-connected matrix-based SST topologies for the application-type under consideration. © 2019 IEEE.

2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019

A Review on Bidirectional Matrix-Based AC-DC Conversion for Modular Solid-State-Transformers

We study the uniform time-reversal-invariant U(1) quantum spin liquid (QSL) with low-energy fermionic quasiparticles for rare-earth pyrochlore magnets and explore its magnetic instability, employing an augmented fermionic parton mean field theory approach. Self-consistent calculations stabilize a uniform U(1) QSL with both gapped and gapless parton excitations as well as fractionalized magnetically ordered phases in an experimentally relevant part of the phase diagram near the classical phase boundaries of the magnetically ordered phases. The gapped QSL has a band structure with a nonzero Z2 topological invariant. The fractionalized magnetically ordered phases bear signatures of both QSL through fermionic excitations as well as magnetic order. Thus, this provides a possible way to understand the unconventional diffuse neutron scattering in rare-earth pyrochlores such as Yb2Ti2O7, Er2Sn2O7, and Er2Pt2O7 at low or zero external magnetic fields. We calculate the dynamic spin structure factor to understand the nature of the diffuse two-particle continuum. © 2019 American Physical Society.

Department of Physics

Fulltext

Physical Review B

Interplay of uniform U (1) quantum spin liquid and magnetic phases in rare-earth pyrochlore magnets: A fermionic parton approach

The use of crude oil as a backup fuel in gas turbines remains an economical option for power plants in petroleum-rich countries like Saudi Arabia. However, operating gas turbines with crude oil can corrode their Hot-Gas-Path (HGP) components due to the formation of vanadium oxides and alkali metal vanadates, when preventative measures are not employed. While the pre-combustion treatment of crude oil fuel is effective at reducing the content of sodium (Na) and potassium (K) in the fuel and, therefore, their resulting combustion products, any pre-combustion removal of vanadium has remained unviable on a commercial scale. Typically, a best practice limit of 0.5 ppmw vanadium is imposed on liquid fuels when inhibitors are not employed, and the total alkali content is limited to 1.0 ppmw. To evaluate the effects of incremental exceedances of such limits on the structural materials and coatings of gas turbines, a high-pressure hot-corrosion test rig was built at King Abdullah University of Science and Technology (KAUST). Arabian Extra Light (AXL) crude oil with a vanadium content of up to 2 ppm was chosen as the test fuel. This burner rig was designed to accommodate high temperatures (~1173 K/ 900 °C) and the combustion of unrefined crude oils at an elevated pressure of up to 15 bar. Highly reduced flow velocities (~1 m/s) were employed to deconvolute erosional effects from corrosion. This experiment exposed the tested materials to combustion products under these conditions for extended periods (up to 500 hours). The development of the rig included several design iterations and changes to the configuration of various sub-systems, owing to some challenges in maintaining stable combustion at low flow rates, management of coke/ash formation from the burning of crude oil, and adequate control over the pressure and temperature during extended experimental campaigns. The present publication summarizes the design and commissioning of this high-pressure hot-corrosion rig facility, and the successful demonstration of several long duration (400+ hour) experimental runs with AXL crude oil, where the environment of the sample section with test coupons was maintained at 5.5 bar and 1173 K. The pressure and temperature inside the sample section of the rig were continuously monitored. The batch of material coupons was removed from the sample section after the runs and sent for corrosion analysis. Deposits resulting from the AXL combustion and fouling were collected from several sections of the rig for analytical analysis. The fuel wash procedure, the design of components in the burner rig, and best practices of operation were also documented. Copyright © 2019 ASME.

Department of Mechanical Engineering

Proceedings of the ASME Turbo Expo

Development of a high-pressure hot-corrosion burner rig for testing structural materials following long exposures to Arabian extra light crude oil combustion products

International Journal of Aerospace and Mechanical Engineering

Mixed mode fracture analyses using finite element method of edge cracked heavy spinning annulus pulley

This study investigated the cracking mechanism of Asphalt-Rubber Gap-graded (AR-Gap) mixtures with various material properties. The research focused on using a monotonic semicircular bending (SCB) test to estimate the cracking potential of AR-Gap mixtures at 0°C and 25°C. A total of 28 asphalt mixtures, including 27 AR-Gap mixtures and 1 conventional dense-graded (DG) mix, covering over 220 data points were utilized for evaluation. The outcome parameter, fracture toughness, KIC, calculated from the SCB test was used to compare and contrast the mixtures’ resistance to cracking at low and intermediate temperatures. At both test temperatures, the results indicated that AR-Gap mixtures have higher fracture resistance (~60 %) than the DG mix. Furthermore, statistical analyses confirmed that asphalt binder type, aggregate gradation, and binder content had significant effects on cracking performance. Aggregate gradation had a more pronounced effect on cracking performance than binder type, followed by binder content. In addition, a KIC predictive model was developed that had excellent statistical goodness-of-fit measures (R2 ≥ 90 %), which can be conveniently utilized in case of unavailability of the test setup. Overall, the findings revealed superior performance characteristics of AR-Gap mixtures that had high potential to resist cracking. Based on the various outcomes, the study was able to recommend aggregate gradation, binder type, and binder content as the parameters that would exhibit higher resistance against cracking failure. It is envisaged that this research would further the state of the art in designing crack-resistant asphalt mixtures. © 2019 by ASTM International.

Department of Civil Engineering

Journal of Testing and Evaluation

Investigation of cracking performance of asphalt-rubber gap-graded mixtures: Statistical overview on materials’ interface

This study evaluated the performance of asphalt-rubber gap-graded (AR-Gap) mixtures under various test conditions and established a novel design toolkit that was proficient to rank the mixtures, which helped recommend the best performing material. A total of 28 asphalt mixtures, including, one dense-graded and 27 AR-Gap mixtures were considered. Euclidean distance approach was utilized to determine the best AR-Gap mixture based on ten pavement material design parameters. It is envisaged that this toolkit will help researchers and practitioners to prioritize the desired combinations of asphalt mixture materials properties, thereby assisting in selection of best performing pavement system for field implementation. © 2019 Elsevier Ltd