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

A 77 GHz polarization-agile radio frequency microelectromechanical system (RF MEMS) patch antenna integrated with single-pole single throw switches is presented. The polarization of the proposed antenna can be switched among linear polarization, right-hand circular polarization, and left-hand circular polarization. The RF MEMS antenna is fabricated on 25 mil alumina with permittivity of 9.8. The reflection and radiation parameters of antenna including return loss, radiation patterns, gain, and axial ratio are measured and are found to be in correlation with simulated results. The proposed work is useful for automotive radar applications. © 2020 Wiley Periodicals, Inc.

World University root node

Department of Electrical Engineering

Microwave and Optical Technology Letters

A 77-GHz polarization-agile microelectromechanical system antenna

Doppler ultrasound based methods are widely used in investigating the vascular hemodynamics and to quantize the blood flow dynamics. But conventional Doppler ultrasound techniques are limited to the investigation of axial flows as it is not sensitive to the transverse flow component. When it comes to non-invasive imaging of the human vasculature, as most of the blood vessels are parallel to the skin surface, the flow is transverse and hence conventional Doppler estimates are not reliable. To tackle this, various methods like cross beam Doppler, cross-correlation methods and multi-transmit multi-receive schemes have been developed in the recent past. Most of the strategies in this regard use plane waves which are electronically steered at different angles for insonification. In this work, the performance of a triangulation based algorithm with non-steered plane wave transmit is investigated for transverse flows. The algorithm makes a best fit out of the triangulation estimates with different receive angles so that the variability in vector estimation with the receive angles are reduced. The performance of the developed algorithm is evaluated with extensive simulations using Field II. The algorithm is tested with different flow profiles at different velocities and the estimates are shown to be promising and the accuracy is comparable with that of other vector flow imaging methods. © 2020 SPIE.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE

Triangulation based vector flow imaging with non-steered plane waves for transverse flows

In ultrasound imaging, a non-linear beamforming algorithm called filtered delay multiply and sum (F-DMAS) has been demonstrated to provide improved contrast and resolution compared to the commonly employed delay and sum (DAS) algorithm. In F-DMAS, the delay compensated radio-frequency narrowband signals from the transducer channels is pairwise multiplied to generate baseband and higher-order harmonic components in the output spectrum. The final image is reconstructed by filtering the second harmonic component to provide better contrast and resolution. However, other generated harmonic components, which are not utilized in the standard F-DMAS could be employed for improved contrast and resolution. In this work, a modification to standard F-DMAS is proposed where the different frequency bands generated through pairwise multiplications are selectively combined through additive or difference compounding techniques to form the final image. The results show that the proposed approach outperforms the standard F-DMAS in terms of contrast and resolution. © 2020 IEEE.

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Delay multiply and sum based selective compounding for enhanced ultrasound imaging

Perovskite-based solar cells are one of the most rapidly emerging photovoltaic devices in terms of their ability to convert sunlight into electrical energy. Although extensively researched upon, their efficiency is still less than the thermo-dynamic limit due to various electrical losses in the device and optical losses in the stack layers that make a perovskite solar cell (PSC). This work focuses on optimizing the thickness of the transport layers (electron and hole transport layers) in the stack for planar PSCs, by accounting for different optical losses in each layer analytically. © 2020 IEEE.

2020 5th IEEE International Conference on Emerging Electronics, ICEE 2020

Optimization of Transport Layer Thickness for Perovskite Solar Cells: An Optical Analysis

This paper proposes a Modular Solid-State-Transformer (SST) topology consisting of bidirectional Matrix-Based AC-DC Dual-Active-Bridge (DAB) submodules. Unlike the conventional SST topologies, the proposed topology offers a single stage Medium Voltage AC (MVAC) - Low Voltage DC (LVDC) conversion. The discussion is focused on the AC-DC DAB submodule of a 1 MVA SST for the Energy Control Centre (ECC) of a microgrid/nanogrid. The possible modulation modes along with the corresponding power transfer limits are presented and a suitable steady-state modulation scheme is identified for the required operating point. The modeling and small-signal analysis of the AC-DC submodule is comprehensively explained. Simulation results including the steady-state operation and the frequency response of the 17.6 kW submodule are presented. © 2020 IEEE.

IECON Proceedings (Industrial Electronics Conference)

A Bidirectional Matrix-Based AC-DC Dual-Active Bridge for Modular Solid-State-Transformers

Cascaded Modular Solid-State Transformer (CMSST) is proposed as an alternative to the conventional transformer for smart grids where controlled bidirectional power flow, provision to integrate distributed generation, grid support with ancillary services and feasibility for islanded operation have become absolute necessity. Even though CMSST is modular in design (both phase-wise and system-wise), voltage balance controllers (VBC) and power balance controllers (PBC) are still required to compensate the mismatches in passive elements of various modules. The design and control philosophy of VBC and PBC are well understood in the literature, however, influence of these balance controllers on steady-state and fault performance is less studied. In this paper, analysis of balance controllers during steady-state, transient and faulty conditions are studied interms of harmonics in grid current, bandwidth of system and choice of fault indicators. The presented analysis is substantiated with experimental results from a 1 kV A CMSST prototype. These findings can serve as a good starting guidelines while choosing appropriate balance controllers for CMSST. © 2020 IEEE.

IEEE PES Innovative Smart Grid Technologies Conference Europe

Analysis of balance controllers for cascaded modular solid-state transformer during steady-state, transient and fault conditions

The current practice of factor of safety computation of pile-stabilised slopes depends substantially on either the extension of methods for normal slopes with the pile-contribution introduced as an additional term or finite-element modelling. Extending conventional methods to analyse pile-stabilised slopes fails to capture the key mechanisms like soil arching, gradual transfer of resistance offered by the pile through the slope, change in slip surface due to introduction of piles and so on. In this paper, a new algorithm is proposed to compute the factor of safety of pile-stabilised slopes, in which the Morgenstern–Price method is modified to incorporate the effect of a pile. The resistance offered by the pile is obtained using a pressure-based method which considers the soil-arching effect in horizontal and vertical directions. The gradual propagation of this resistance offered by the pile is incorporated through an iterative procedure, unlike the conventional methods. The algorithm considers the change in slip surface due to the introduction of the pile. The factor of safety values computed using the proposed algorithm were found to be in close agreement with that obtained from finite-element modelling. Moreover, a simple technique to determine the optimal location of stabilising piles and pile-spacing is also presented.

Department of Civil Engineering

Fulltext

Geotechnical Research

Factor of safety of pile-stabilised slopes: an algorithm incorporating soil-arching effect

We study four problems namely, Campbell's source coding problem, Arikan's guessing problem, Huieihel et al.'s memoryless guessing problem, and Bunte and Lapidoth's task partitioning problem. We observe a close relationship among these problems. In all these problems, the objective is to minimize moments of some functions of random variables, and Rényi entropy and Sundaresan's divergence arise as optimal solutions. This motivates us to establish a connection among these four problems. In this paper, we study a more general problem and show that Rényi and Shannon entropies arise as its solution. We show that the problems on source coding, guessing and task partitioning are particular instances of this general optimization problem, and derive the lower bounds using this framework. We also refine some known results and present new results for mismatched version of these problems using a unified approach. We strongly feel that this generalization would, in addition to help in understanding the similarities and distinctiveness of these problems, also help to solve any new problem that falls in this framework.

Department of Computer Science and Engineering

Deep AI

A Unified Framework for Problems on Guessing, Source Coding and Task Partitioning

We report a new site for the \textsl{s}-process in rotating massive metal-poor stars. Above a critical rotation speed, such stars evolve in a quasi-chemically-homogeneous fashion, which gives rise to a prolific \textsl{s}-process. Rotation-induced mixing results in primary production of $^{13}$C, which subsequently makes neutrons via $^{13}\mathrm{C}(\alpha,\mathrm{n})^{16}\mathrm{O}$ during core He burning. Neutron capture can last up to $\sim 10^{13}\,\mathrm{s}$ with the peak central neutron density ranging from $\sim10^7$ to $10^{8}\,\mathrm{cm}^{-3}$. Depending on the rotation speed and the mass loss rate, a strong \textsl{s}-process can occur with production of elements up to Bi for progenitors with initial metallicities of $[Z]\lesssim -1.5$. This result suggests that rapidly-rotating massive metal-poor stars are likely the first site for the main \textsl{s}-process. We find that these stars can potentially explain the early onset of the \textsl{s}-process and some of the carbon-enhanced metal-poor (CEMP-\textsl{s} and CEMP-\textsl{r/s}) stars with strong enrichment attributed to the \textsl{s}-process or a mixture of the \textsl{r}-process and the \textsl{s}-process.

Department of Physics

Scanning Electron Microsc Meet

New s-process Site in Rapidly-Rotating Massive Pop II Stars

We propose a framework to model ferroelectric negative capacitance: electrostatic Micro Electro Mechanical Systems (MEMS) hybrid actuators and analyze their dynamic (step input) response. Using this framework, we report the first proposal for reduction in the dynamic pull-in and pull-out voltages of the hybrid actuators due to the negative capacitance of the ferroelectric. The proposed model also reveals the effect of ferroelectric thickness on the dynamic pull-in and pull-out voltages and the effect of ferroelectric damping on the energy dissipated during actuation. We infer from our analysis that the hybrid actuators are better than the standalone MEMS actuators in terms of operating voltage and energy dissipation. Further, we show that one can trade-off a small part of the reduction in actuation voltage to achieve identical pull-in times in the hybrid and standalone MEMS actuators, while still consuming substantially lower energy in the former as compared to the latter. The circuit compatibility of the proposed hybrid actuator model makes it suitable for analysis and evaluation of various heterogeneous systems consisting of hybrid MEMS actuators and other electronic devices.