Explaining the CMS eejjeejj and e missing pT jje\ \rm{missing}\ p_T \ jj excess and leptogenesis in superstring inspired E6E_6 models

We show that superstring inspired $E_6$ models can explain both the recently detected excess $eejj$ and $e\ \rm{missing}\ p_T \ jj$ signals at CMS, and also allow for leptogenesis. Working in a R-parity conserving low energy supersymmetric effective model, we show that the excess CMS events can be produced via the decay of exotic sleptons in Alternative Left-Right Symmetric Model of $E_6$, which can also accommodate leptogenesis at a high scale. On the other hand, either the $eejj$ excess or the $e\ \rm{missing}\ p_T \ jj$ excess can be produced via the decays of right handed gauge bosons, but some of these scenarios may not accommodate letptogenesis as there will be strong $B-L$ violation at low energy, which, along with the anomalous fast electroweak $B+L$ violation, will wash out all baryon asymmetry. Baryogenesis below the electroweak scale may then need to be implemented in these models.Comment: v3: 9 pages, 9 figures, matches published versio

Transition boundaries and an order-to-chaos map for the flow field past a flapping foil

peer reviewedThe present study focuses on identifying dynamical transition boundaries and presents an order-to-chaos map for the unsteady flow field of a flapping foil in the low Reynolds number regime. The effect of an extensive parametric space, covering a large number of kinematic conditions, has been investigated. It is shown that the conventional non-dimensional parameters cannot effectively capture the changes in the flow field due to the variations in the relevant kinematic parameters and are unable to demarcate the dynamical transition boundaries. Two new non-dimensional measures - maximum effective angle of attack and a leading-edge amplitude-based Strouhal number - are proposed here, which can capture the physical effect of the parametric variations on the wake dynamics. The study proposes generalised transition boundaries and an order-to-chaos map through a transitional regime in terms of these two newly proposed parameters. Published data from the existing literature have also been tested to verify the proposed transition model. It is seen that despite the wide variety of the parametric combinations, the dynamical states from both the new and the published data corroborate well the proposed boundaries, giving credibility to the order-to-chaos map

A new approach to ward off Error Propagation Effect of AES – Redundancy Based Technique Redefined

Advanced Encryption Standard (AES) [1, 2] is a great research challenge. It has been developed to replace the Data Encryption Standard (DES). AES suffers from a major limitation of Error propagation effect. To tackle this limitation, two methods are available. One is Redundancy Based Technique and the other one is Bite Based Parity Technique. The first one has a significant advantage of correcting any error on definite term over the second one but at the cost of higher level of overhead and hence lowering the processing speed. In this paper we have proposed a new approach based on the Redundancy Based Technique that would certainly speed up the process of reliable encryption and hence the secured communication. Keywords Advanced Encryption Standard, Error Propagation Effect, Redundancy Based Technique, Longitudinal Redundancy Check Cod

Interplay between Co-3d and Ce-4f magnetism in CeCoAsO

We have investigated the ground state properties of polycrystalline CeCoAsO by means of magnetization, specific heat and solid state NMR. Susceptibility and specific-heat measurements suggest a ferromagnetic order at about, $T_\mathrm{C}$=75 K. No further transitions are found down to 2 K. At 6.5 K a complex Schottky type of anomaly shows up in the specific heat results. The interplay between Ce-4f and Co-3d magnetism being responsible for that anomaly is discussed. Furthermore $^{75}$As NMR investigations have been performed to probe the magnetism on a microscopic scale. As-NMR spectra are analysed in terms of first and second order quadrupolar interaction. The anisotropic shift component $K_{\mathrm{ab}}$ and $K_{\mathrm{c}}$ could be derived from the $^{75}$As powder spectra. Towards lower temperature a strong shift anisotropy was found. Nonetheless $K_{\mathrm{iso}}$ tracks the bulk susceptibility down to $T=$50 K very well. Furthermore the presence of weak correlations among the Ce ions in the ferromagnetic state is discussed. The observed increase of $C/T$ towards lower temperatures supports this interpretation.Comment: 6 pages, 4 figures, Accepted in Physical Review

An automated web crawl methodology to analyze the online privacy landscape

Protecting end-users privacy and building trust are the two most important factors needed to support the growth of ecommerce. The increased dependence on the Internet for a wide variety of daily transactions causes a corresponding loss in privacy for many users, as virtually all websites collect data from users directly or indirectly while performing business with them. In this thesis I have used a web crawler named “iWatch” which serves as an instrument to collect basic statistics on the state of privacy, security, and data-collection practices on the web. I have looked at several interesting practices, and ways of examining the data. This thesis is also meant to serve as a point for reflection and discussion about which practices to observe, and how the raw data from such a system can and should be evolved and made available to a wider audience. The purpose of this thesis is to show web-crawling is a valid approach to mass data collection over the internet with the aim of predicting privacy practices and analyzing how they have evolved in the last three years in terms of geography, legislation, risks, biases and flows. Finally I demonstrate methods to show how to control bias while collecting data, and I propose a probabilistic mathematical model to limit the depth of search to achieve wider breadth for web crawling techniques in the future

GUEST EDITORIAL

Nanoelectronic devices of various kinds of are essential for VLSI circuits. The struggle to follow Moore’s law is becoming increasingly difficult and complex, requiring multitudinous novel approaches in order to continue decreasing dimensions of the devices which are already firmly established in the nano-world. As an example, the most advanced state of the art VLSI’s (microprocessors) currently can contain more than 50 billion transistors per chip. As far as the actual physical dimensions are concerned, in 2021 the IBM company announced their 2 nm chip.The efforts behind such achievements are enormous. This special issue on advanced planar nanoelectronics investigates some points of interest related to the physics of such devices, as well as their simulation, thus giving its contribution to the existing trends in this rapidly evolving and constantly expanding field

Controlling the chaotic wake of a flapping foil by tuning its chordwise flexibility

Effects of chord-wise flexibility as an instrument to control chaotic transitions in the wake of a flexible flapping foil have been studied here using an immersed boundary method-based in-house fluid-structure-interaction solver. The ability of the flapping foil at an optimum level of flexibility to inhibit chaotic transition, otherwise encountered in a similar but rigid configuration, has been highlighted. The rigid foil manifests chaotic transition through a quasi-periodic-intermittency route at high dynamic plunge velocities; whereas, increasing the level of flexibility gradually regularises the aperiodic behaviour through a variety of interesting wake patterns. If flexibility is increased beyond an optimum level, aperiodicity sets in again and robust chaos is restored at very high flexibility levels. The mechanisms of triggering the order-to-chaos transition are different between the rigid and the high flexibility cases. Along the route to order and back to chaos, the flexible foil exhibits different flow-field behaviours, including far-wake switching, primary \& secondary vortex streets, bifurcated wakes and interactive vortices between the bifurcated wakes. The underlying interaction mechanisms of the flow-field vortices responsible for the associated dynamical signatures of the wake have been closely tracked. This study further examines the optimum propulsive performance range of the flexible flapper and investigates its connection with the periodicity/regularity of the system

Chordwise flexible aft-tail suppresses jet-switching by reinstating wake periodicity in a flapping foil

peer reviewedThe effect of a chordwise flexible aft-tail of a rigid heaving aerofoil on the dynamical transitions of the trailing-wake is studied here. The two-way coupled fluid-solid dynamics is simulated using an in-house fluid-structure interaction (FSI) platform, comprising a discrete forcing immersed boundary method based incompressible Navier-Stokes solver, weakly coupled with a finite difference method based structural solver. The FSI dynamics is studied in comparison to the corresponding rigid tail configuration. For the latter, mild jet-switching due to quasi-periodic movement of the wake vortices gives way to vigorous jet-switching as the dynamics transitions to a state of intermittency, where the quasi-periodic behaviour gets interspersed with chaotic windows. Introduction of a moderately flexible tail regularises this intermittent dynamics, eliminating jet-switching. The wake exhibits a deflected reverse Kármán pattern with fluctuating angles, governed by quasi-periodicity. With a highly flexible tail (very low rigidity), the wake shows almost a symmetric reverse Kármán street as periodicity is restored. Flexibility of the aft-tail is next controlled by changing its length, and flow is regularised and periodicity retained for moderate rigidity for increased length. Different dynamical states are established through robust nonlinear dynamical tools. The underlying flow-field behaviour, instrumental in suppressing the jet-switching phenomenon, is identified through a detailed investigation of the near-field vortex interactions dictated by the dynamics. A suite of measures has also been derived from the unsteady flow field to quantify the interactions of the key near-field vortices with a view to understanding the mechanism of switching and its subsequent suppression through flexibility