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

In a rotor bearing system operating with constant angular acceleration, after passing through the critical speed, typical beat characteristics are observed because the transverse vibration response contains both excited and natural motion, and shortly after passing resonance, vibrations with close frequencies appear. The present study explains a method for estimating damping of rotor bearing systems from transient beat vibration signals observed during run up stage. A mathematical derivation to prove that a part of run-up vibration of the rotor system consists of beat phenomenon when the system crosses critical speed. It is also observed from the mathematical model that the beat vibrations depend on the damping in the system. This beat response is considered for Hilbert analysis and the damping is estimated. Increase in angular acceleration of the rotor will increase the damping. This paper investigates how the damping varies with respect to different angular acceleration values of the rotor bearing system. Experimental validation of the beat phenomenon and damping estimation are done for the rotor system. The proposed method is validated by using half-power band width method applied to run-up response. © 2014, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

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Department of Mechanical Engineering

Journal of Mechanical Science and Technology

Damping identification in rotors from run-up beat responses using Hilbert transforms

Many types of rotating components commonly operate above the first or second critical speed and they are subjected to run-ups and shutdowns frequently. The present study focuses on developing FRF of rotor bearing systems for damping estimation from swept-sine excitation. The principle of active vibration control states that with increase in angular acceleration, the amplitude of vibration due to unbalance will reduce and the FRF envelope will shift towards the right (or higher frequency). The frequency response function (FRF) estimated by tracking filters or Co-Quad analyzers was proved to induce an error into the FRF estimate. Using Fast Fourier Transform (FFT) algorithm and stationary wavelet transform (SWT) decomposition FRF distortion can be reduced. To obtain a theoretical clarity, the shifting of FRF envelope phenomenon is incorporated into conventional FRF expressions and validation is performed with the FRF estimated using the Fourier Transform approach. The half-power bandwidth method is employed to extract damping ratios from the FRF estimates. While deriving half-power points for both types of responses (acceleration and displacement), damping ratio (ζ) is estimated with different approximations like classical definition (neglecting damping ratio of order higher than 2), third order (neglecting damping ratios with order higher than 4) and exact (no assumptions on damping ratio). The use of stationary wavelet transform to denoise the noise corrupted FRF data is explained. Finally, experiments are performed on a test rotor excited with different sweep rates to estimate the damping ratio. © 2013 Elsevier Ltd.

Journal of Sound and Vibration

Swept sine testing of rotor-bearing system for damping estimation

Department of Civil Engineering

7th International congress on environmental geotechnics, Australia, November {\ldots}

Tensile strength and permeability behaviour of soil barrier material with and without polyester fibers

High-k dielectric oxides are supposedly ideal gate-materials for ultra-high doping in graphene and other 2D-crystals. Here, we report a temperature-dependent electronic transport study on chemical vapor deposited-graphene gated with SrTiO3 (STO) thin film substrate. At carrier densities away from charge neutrality point the temperature-dependent resistivity of our graphene samples on both STO and SiO2/Si substrates show metallic behavior with contributions from Coulomb scattering and flexural phonons attributable to the presence of characteristic quasi-periodic nano-ripple arrays. Significantly, for graphene samples on STO substrates we observe an anomalous 'slope-break' in the temperature-dependent resistivity for T550 to 100 K accompanied by a decrease in mobility above 30 K. Furthermore, we observe an unusual decrease in the gate-induced doping-rate at low temperatures, despite an increase in dielectric constant of the substrate. We believe that a complex mechanism is at play as a consequence of the structural phase transition of the underlying substrate showing an anomalous transport behavior in graphene on STO. The anomalies are discussed in the context of Coulomb as well as phonon scattering.

Department of Physics

Fulltext

Scientific Reports

Unconventional transport through graphene on SrTiO 3: A plausible effect of SrTiO3 phase-transitions

3D-MPSoC offer great performance and scalability benefits. However, due to strong vertical thermal correlation and increased power density, thermal challenges in 3D-MPSoC are critical. In this paper, we propose a novel thermal aware task scheduling technique that combine intelligent task mapping with DVFS to minimize the peak temperature of the system. Particularly, our approach leverages on the fundamental thermal characteristics of 3D architecture when mapping tasks to processing cores and employing DVFS at design time followed by a simple thermal optimization step at run time. Our experiments validate the efficiency of our approach in peak temperature minimization up to 14°C compared to other existing methods. © 2014 IEEE.

Department of Computer Science and Engineering

Proceedings - IEEE International Symposium on Rapid System Prototyping, RSP

Thermal-aware task scheduling for peak temperature minimization under periodic constraint for 3D-MPSoCs

The boxicity (resp. cubicity) of a graph G(V,E) is the minimum integer k such that G can be represented as the intersection graph of axis parallel boxes (resp. cubes) in Rk. Equivalently, it is the minimum number of interval graphs (resp. unit interval graphs) on the vertex set V, such that the intersection of their edge sets is E. The problem of computing boxicity (resp. cubicity) is known to be inapproximable, even for restricted graph classes like bipartite, co-bipartite and split graphs, within an O(n1-ε)-factor for any ε&gt;0 in polynomial time, unless NP=ZPP. For any well known graph class of unbounded boxicity, there is no known approximation algorithm that gives n1-ε-factor approximation algorithm for computing boxicity in polynomial time, for any ε&gt;0. In this paper, we consider the problem of approximating the boxicity (cubicity) of circular arc graphs - intersection graphs of arcs of a circle. Circular arc graphs are known to have unbounded boxicity, which could be as large as Ω(n). We give a (2+1/k)-factor (resp.(2+ logn/k)-factor) polynomial time approximation algorithm for computing the boxicity (resp. cubicity) of any circular arc graph, where k≥1 is the value of the optimum solution. For normal circular arc (NCA) graphs, with an NCA model given, this can be improved to an additive two approximation algorithm. The time complexity of the algorithms to approximately compute the boxicity (resp. cubicity) is O(mn+n2) in both these cases, and in O(mn+kn2)=O(n3) time we also get their corresponding box (resp. cube) representations, where n is the number of vertices of the graph and m is its number of edges. Our additive two approximation algorithm directly works for any proper circular arc graph, since their NCA models can be computed in polynomial time. © 2014 Elsevier Ltd. All rights reserved.

Discrete Applied Mathematics

A constant factor approximation algorithm for boxicity of circular arc graphs

We have investigated, experimentally and theoretically, the series (Na1-xLix)2IrO3. Contrary to what has been believed so far, only for x≤0.25 does the system form uniform solid solutions where Li preferentially goes to the Ir2Na planes, as observed in our density functional theory calculations and consistent with x-ray diffraction analysis. For larger Li content, as evidenced by powder x-ray diffraction, scanning electron microscopy, and density functional theory calculations, the system shows a miscibility gap and a phase separation into an ordered Na3LiIr2O6 phase with alternating Na3 and LiIr2O6 planes, and a Li-rich phase close to pure Li2IrO3. For x≤0.25 we observe (1) an increase of c/a with Li doping up to x=0.25, despite the fact that c/a in pure Li2IrO3 is smaller than in Na2IrO3, and (2) a gradual reduction of the antiferromagnetic ordering temperature TN and ordered moment. In view of our results showing clear evidence for phase separation for 0.25≤x≤0.6, more detailed studies are needed to confirm the presence or absence of phase separation at the higher doping x∼0.7, where a continuum quantum phase transition has been proposed previously. © 2014 American Physical Society.

Physical Review B - Condensed Matter and Materials Physics

Effect of isoelectronic doping on the honeycomb-lattice iridate A2 IrO3

In this paper a fault based attack on MDS-AES has been proposed. It has been shown that inducing random byte fault at the input of the ninth round of the MDS-AES algorithm the key can be retrieved. Simulation shows that two faulty cipher text pairs are required to deduce the key without any brute-force search. If one faulty encryption is considered then the actual key can be ascertained with a brute-force search of complexity 216. To the best of our knowledge, this work is the first attempt to explore fault based attack on MDS-AES.

Department of Data Science

International Journal of Network Security

A fault based attack on MDS-AES

We present a cache-timing attack on the Advanced Encryption Standard (AES) [14] with the potential to be applied remotely and develop an evaluation framework for comparing the relative performance of the attacks under various simulated network conditions. We examine Bernstein's original AES cache-timing attack [3], and its variants [6, 12, 10]. We conduct an analysis of network noise and develop a hypothesis fishing concept in order to reduce the number of samples required to recover a key in our implementation of the attacks of [3]. Our rough estimate for the number of samples required is about 2 × 10 9 which is comparable to the estimate 4 × 109 of our month-long experiment using Bernstein's technique [3]. Copyright © 2014 ACM.

ACM International Conference Proceeding Series

Remote cache-timing attacks against AES

Equimolar combination of a series of binuclear half-sandwich p-cymene ruthenium(II) building units [Ru2(μ-η4-C 2O4)(MeOH)2(η6-p-cymene) 2](OTf)2 [1a](OTf)2, [Ru2(μ- η4-N,N′-diphenyloxamidato)( MeOH)2(η6-p- cymene)2](OTf)2 [1b](OTf)2 and [Ru 2(μ-η4-C6H2O 4)(MeOH)2(η6-p-cymene)2](OTf) 2 [1c](OTf)2 separately with imidazole-based ditopic ligands (L1-L2) in methanol yielded a series of tetranuclear metallamacrocycles [2-7](OTf)4, respectively [L 1 = 1,4-bis(imidazole-1-yl)benzene; L2 = 4,4′-bis(imidazole-1-yl)biphenyl; OTf- = O3SCF3 -]. Similarly, the reaction of [Ru2(μ- η4-C2O4)(MeOH)2(η 6-pcymene)2](OTf)2 [1a](OTf)2 with a triazine-based tritopic ligand 1,3,5-tris(imidazole-1-yl)triazine (L 3) in 3:2 M ratio afforded an unexpected tetranuclear macrocycle [8](OTf)4 instead of an expected trigonal prismatic cage [8a](OTf)6. All the self-assembled macrocycles [2-8](OTf)4 were isolated in moderate to high yields and were fully characterized by multinuclear [1H, 19F] NMR, IR and electrospray ionization mass spectrometry (ESI-MS). In addition, X-ray diffraction study on the single crystals of [3](OTf)4 and [8](OTf)4 also indicated the formation [2+2] self-assembled macrocycles. Despite the possibility of formation of different conformational isomeric macrocycles (syn-and anti) and polymeric product due to free rotation of ligand sites of imidazole linkers, the selective formation of single conformational isomer (anti) as the only product is quite interesting. Furthermore, the photo-and electrochemical properties of these assemblies have been studied using UV/Vis absorption and cyclic voltammetry analysis. © 2013 Elsevier B.V. All rights reserved.