Insulator superconductor transition on solid inert gas substrates

We present observations of the insulator-superconductor transition in ultrathin films of Bi on solid xenon condensed on quartz and on Ge on quartz. The relative permeability $\epsilon_{r}$ ranges from 1.5 for Xe to 15 for Ge. Though we find screening effects as expected, the I-S transition is robust, and unmodified by the substrate. The resistance separatrix is found to be close to $h/4e^2$ and the crossover thickness close to 25 $\AA$ for all substrates. I-V studies and Aslamazov-Larkin analyses indicate superconductivity is inhomogeneous. The transition is best described in terms of a percolation model.Comment: Submitted to LT23 Proceeding

The Particle Swarm Optimization Based Linear Cryptanalysis of Advanced Encryption Standard Algorithm

The tremendous development in internet technology, wireless communication and the type of internet capable devices has increased the amount of network usage .Millions of users are associated with the network and thus there is need for network security. The sensitive data that is deposited and transmitted on the internet need protection from attackers and eavesdroppers who perform illegal actions. Cryptography algorithms are the key factor of the security mechanisms used for data storage and uninterrupted network transmissions. The data security purely depends on the Cryptography algorithm hence the keys must be managed in a good way. Security mechanisms are developed when a threat to security is identified. To identify the security risk associated with AES algorithm, a computational intelligence based approach for known cryptanalysis of Advanced Encryption Standard algorithm is introduced. Particle swarm optimization based cryptanalysis is used much now a days because of its fast convergence rate. A PSO oriented cryptanalysis technique for breaking the key used in advance encryption standard algorithm is introduced. This approach is for known cipher text-only attack for an AES encryption system, where the key is deduced in a minimum search space in contrast to the Brute Force Attack. The key used in AES can be detected effectively with Particle Swarm Optimization DOI: 10.17762/ijritcc2321-8169.16040

Local economic effects of Brexit

This paper studies local economic impacts of the increases in trade barriers associated with Brexit. Predictions of the local impact of Brexit are presented under two different scenarios, soft and hard Brexit, which are developed from a structural trade model. Average effects are predicted to be negative under both scenarios, and to be more negative under hard Brexit. The spatial variation in negative shocks across areas is higher in the latter case as some local areas are particularly specialised in sectors that are predicted to be badly hit by hard Brexit. Areas in the South of England, and urban areas, are harder hit by Brexit under both scenarios. Again, this pattern is explained by sector specialisation. Finally, the areas that were most likely to vote remain are those that are predicted to be most negatively impacted by Brexit

Anomalous lithium adsorption propensity of monolayer carbonaceous materials: a density functional study

Interaction between lithium and carbonaceous materials has gained a lot of importance in lithium battery industry as an important source of energy and storage. The size, dimension, curvature and chirality of the carbonaceous materials are found to be very important factors in controlling the sequential binding of lithium. The propensity of lithium binding to the monolayer carbonaceous materials has been studied using Density functional theory (DFT). Structural and energetical parameters of the complexes have been analyzed through interaction energy, sequential energy, Mulliken population analysis and spin density distribution. Spindensity of odd Li doped systems reveals the preferences for addition of further lithium atoms on the surface. Upon analyzing the interaction energy in armchair carbon nanotubes (A-CNTs) and zigzag carbon nanotubes (Z-CNTs), it has been observed that external and internal surfaces of CNTs have contrasting binding preferences for sequential addition of Li atoms. Internal surface is found to be more feasible site for lithium adsorption than the external surface. This current study provides fundamental understanding of the mechanism of lithium adsorption in lithium battery

Vortices and the mixed state of ultrathin Bi films

Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These show hysteresis for all films, grown both with and without thin Ge underlayers. Films on Ge underlayers, close to superconductor-insulator transition, show a peak in the critical current, indicating a structural transformation of the vortex solid. These underlayers, used to make the films more homogeneous, are found to be more effective in pinning the vortices. The upper critical fields ($B_{c2}$) of these films are determined from the resistive transitions in perpendicular magnetic field. The temperature dependence of the upper critical field is found to differ significantly from Ginzburg-Landau theory, after modifications for disorder.Comment: Submitted to LT23 Proceeding

Analysis of Flow Fields in a Flexible Tube with Periodic Constriction

Numerical techniques based on pressure-velocity formulation have been adopted to solve approximately, the governing equations for viscous flows through a tube (simulating an artery) with a periodic constriction. The effect of the constriction as well as the rigid of the tube, on the flow characteristics, and its consequences for arterial disease is the focus of this investigation. The unsteady incompressible Navier-Stokes equations are solved by using the finite-difference technique in staggered grid distribution. The haemodynamic factors like wall shear stress, pressure and velocity are analyzed through their graphical representations. Maximum resistance is attained in case of rigid stenosed tube rather than the flexible one. The main result is to contribute that the recirculating region is larger in case of a rigid tube than that of flexible one

Evolution of Glassy Carbon Microstructure: In Situ Transmission Electron Microscopy of the Pyrolysis Process

Glassy carbon is a graphene-rich form of elemental carbon obtained from pyrolysis of polymers, which is composed of three-dimensionally arranged, curved graphene fragments alongside fractions of disordered carbon and voids. Pyrolysis encompasses gradual heating of polymers above 900 degree C under inert atmosphere, followed by cooling to room temperature. Here we report on an experimental method to perform in situ high-resolution transmission electron microscopy (HR-TEM) for the direct visualization of microstructural evolution in a pyrolyzing polymer in the 500-1200 degree C temperature range. The results are compared with the existing microstructural models of glassy carbon. Reported experiments are performed at 80 kV acceleration voltage using MEMS-based heating chips as sample substrates to minimize any undesired beam-damage or sample preparation induced transformations. The outcome suggests that the geometry, expansion and atomic arrangement within the resulting graphene fragments constantly change, and that the intermediate structures provide important cues on the evolution of glassy carbon. A complete understanding of the pyrolysis process will allow for a general process tuning specific to the precursor polymer for obtaining glassy carbon with pre-defined properties.Comment: Revised version due to minor corrections in the text and addition of an autho