Exact results for quench dynamics and defect production in a two-dimensional model

We show that for a d-dimensional model in which a quench with a rate \tau^{-1} takes the system across a d-m dimensional critical surface, the defect density scales as n \sim 1/\tau^{m\nu/(z\nu +1)}, where \nu and z are the correlation length and dynamical critical exponents characterizing the critical surface. We explicitly demonstrate that the Kitaev model provides an example of such a scaling with d=2 and m=\nu=z=1. We also provide the first example of an exact calculation of some multispin correlation functions for a two-dimensional model which can be used to determine the correlation between the defects. We suggest possible experiments to test our theory.Comment: 4 pages including 4 figures; generalized the discussion of the defect density scaling to the case of arbitrary critical exponents, and added some references; this version will appear in Physical Review Letter

A robot design for wind generator support structure inspection

In recent time, the development of wind tower inspection has been very crucial for the overall performance of the wind turbine. In order to maintain, monitor and determine the life span of the tower, an investigation of robot design is discussed. It presents how to design and construct a robot that can climb the tower and rotate 360° . A ring system which is in a circular shape robot is designed that allows the device to fit in the structure of the wind generator tower. The rotational module is designed to allow the wheels to rotate and be able to go in a circular motion. Also it is designed with a suspension that allows the robot to go through any obstacle. This paper also presents the FEA spring stress analysis and Simulink control system model to find the optimal parameters that are required for the wind tower climbing robot

On Upward Drawings of Trees on a Given Grid

Computing a minimum-area planar straight-line drawing of a graph is known to be NP-hard for planar graphs, even when restricted to outerplanar graphs. However, the complexity question is open for trees. Only a few hardness results are known for straight-line drawings of trees under various restrictions such as edge length or slope constraints. On the other hand, there exist polynomial-time algorithms for computing minimum-width (resp., minimum-height) upward drawings of trees, where the height (resp., width) is unbounded. In this paper we take a major step in understanding the complexity of the area minimization problem for strictly-upward drawings of trees, which is one of the most common styles for drawing rooted trees. We prove that given a rooted tree $T$ and a $W\times H$ grid, it is NP-hard to decide whether $T$ admits a strictly-upward (unordered) drawing in the given grid.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

Aadhaar (Индия): национальная программа биометрической идентификации (опыт и реализация)

The scope of this paper is to paint a word picture of the National Biometric Identificatio

Digital India: E-government initiative

Digital India is an initiative by the government of India, along with several other parties to provide a digital interface to the government’s services to citizens electronically, by improved online infrastructure and by increasing Internet connectivity

Analysis of Mechanical Adhesion Climbing Robot Design for Wind Tower Inspection

Maintenance of wind turbine farms is a huge task, with associated significant risks and potential hazard to the safety and well-being of people who are responsible for carrying the tower inspection tasks. Periodic inspections are required for wind turbine tower to ensure that the wind turbines are in full working order, with no signs of potential failure. Therefore, the development of an automated wind tower inspection system has been very crucial for the overall performance of the renewable wind power generation industry. In order to determine the life span of the tower, an investigation of robot design is discussed in this paper. It presents how a mechanical spring-loaded climbing robot can be designed and constructed to climb and rotate 360° around the tower. An adjustable circular shape robot is designed that allows the device to fit in different diameters of the wind generator tower. The rotational module is designed to allow the wheels to rotate and be able to go in a circular motion. The design further incorporates a suspension that allows the robot to go through any obstacle. This paper also presents a finite element spring stress analysis and Simulink control system model to find the optimal parameters that are required for the wind tower climbing robot

High-temperature oxidation behaviour of a TiAl-based alloy subjected to aluminium hot-dipping

In this research the oxidation resistance at high temperature of a TiAl-based alloy has been improved by hot-dipping the alloy in molten aluminium and by performing an interdiffusion process. After selecting the best process parameters, a compact TiAl3 coating characterized by an almost constant thickness was formed on the surface. Isothermal oxidation tests, carried out at 900, 950 and 1000 °C, showed that the coated alloy is able to form a continuous and thin alumina layer that is very protective. Microstructural investigations highlighted that, above 900 °C, long residence times at high temperature determine the diffusion through the TiAl3 layer of Cr that favours migration toward the outer surface of Al and thus the formation of a self-healing alumina layer

Universal transition of spectral fluctuation in particle-hole symmetric system

We study the spectral properties of a multiparametric system having particle-hole symmetry in random matrix setting. We observe a crossover from Poisson to Wigner-Dyson like behavior in average local ratio of spacing within a spectrum of single matrix as a function of effective single parameter referred to as complexity parameter. The average local ratio of spacing varies logarithmically in complexity parameter across the transition. This behavior is universal for different ensembles subjected to same matrix constraint like particle-hole symmetry. The universality of this dependence is further established by studying interpolating ensemble connecting systems with particle-hole symmetry to that with chiral symmetry. For each interpolating ensemble the behavior remains logarithmic in complexity parameter. We verify this universality of spectral fluctuation in case of a 2D Su-Schrieffer-Heeger (SSH) like model along with the logarithmic dependence on complexity parameter for ratio of spacing during transition from integrable to non-integrable limit

Construction of the Soudan 2 detector

Progress in the construction of the Soudan 2 nucleon decay detector which is being built at the Soudan iron mine in Minnesota is discussed. The expected event rate and characteristics of low energy neutrino events, muon events, multiple muon events, and other cosmic ray phenomena are discussed