Mechanism of organization increase in complex systems

This article proposes a variational approach to describe the evolution of organization of complex systems from first principles, as increased efficiency of physical action. Most simply stated, physical action is the product of the energy and time necessary for motion. When complex systems are modeled as flow networks, this efficiency is defined as a decrease of action for one element to cross between two nodes, or endpoints of motion—a principle of least unit action. We find a connection with another principle, that of most total action, or a tendency for increase of the total action of a system. This increase provides more energy and time for minimization of the constraints to motion to decrease unit action, and therefore, to increase organization. Also, with the decrease of unit action in a system, its capacity for total amount of action increases. We present a model of positive feedback between action efficiency and the total amount of action in a complex system, based on a system of ordinary differential equations, which leads to an exponential growth with time of each and a power law relation between the two. We present an agreement of our model with data for core processing units of computers. This approach can help to describe, measure, manage, design, and predict future behavior of complex systems to achieve the highest rates of self‐organization and robustness. © 2014 Wiley Periodicals, Inc. Complexity 21: 18–28, 2015     

Boosted UV emission at 349 nm from mesoporous ZnS

Relatively oxygen-free mesoporous cubic ZnS particles were synthesised via a facile solvo-hydrothermal route using a water–acetonitrile combination. Boosted UV emission at 349 nm is observed from the ZnS prepared by the solvo-hydrothermal route. The increased intensity of this UV emission is attributed to activation of whispering gallery modes of almost elliptical microstructures made of porous nanostructures.     

An introduction to percolation theory

Percolation theory, the theory of the properties of classical particles interacting with a random medium, is of wide applicability and provides a simple picture exhibiting critical behaviour, the features of which are well understood and amenable to detailed calculation. In this review the concepts of percolation theory and the general features associated with the critical region about the onset of percolation are developed in detail. In particular, several dimensional invariants are examined which make it possible to unify much of the available information, and to extend the insights of percolation theory to processes which have not yet received numerical study. The compilation of the results of percolation theory, both exact and numerical, is believed to be complete through 1970. A selective bibliography is given. In a concluding chapter several recent applications of percolation theory to classical and to quantum mechanical problems are discussed.     

Investigation on interchannel crosstalk at ADM for an optical ring network

In this paper, we investigated the effect of interchannel crosstalk at ADM of a ring network at sweeping bandwidth of filters. Analysis has been done in a ring network [G.P. Agrawal, Fiber Optic Communication System, Wiley-interscience, New York, 1997; Tim Gyselings et al., Crosstalk analyses of multi-wavelength optical cross connects, J. Lightwave Technol. 17 (1999) 1273; R. Ramaswami, K.N. Sivarajan, Optical Networks: A Practical Perspective, Morgan Kaufmann, Los Altos, CA, 1998] that contains four nodes communication signal over two channels at 1552.2 nm. At the bit rate of 10 Gbps, ADMs at each node is modeled by using WDM add and WDM drop components. The distance between nodes is taken 12.5 and 25 km and an ideal amplifier is inserted just before one of the node to compensate for the total fiber loss in the ring. Dispersion and nonlinear effects of fibers are disabled to observe the crosstalk effect of ADM at sweeping bandwidth from 10 to 40 GHz of fourth-order Bessel filters.     

Kinetic and mechanistic studies of some aliphatic amines' oxidation by sodium N‐bromo‐p‐toluenesulfonamide in hydrochloric acid medium

Oxidations of n‐propyl, n‐butyl, isobutyl, and isoamyl amines by bromamine‐T (BAT) in HCl medium have been kinetically studied at 30°C. The reaction rate shows a first‐order dependence on [BAT], a fractional‐order dependence on [amine], and an inverse fractional‐order dependence on [HCl]. The additions of halide ions and the reduction product of BAT, p‐toluenesulfonamide, have no effect on the reaction rate. The variation of ionic strength of the medium has no influence on the reaction. Activation parameters have been evaluated from the Arrhenius and Eyring plots. Mechanisms consistent with the preceding kinetic data have been proposed. The protonation constant of monobromamine‐T has been evaluated to be 48 ± 1. A Taft linear free‐energy relationship is observed for the reaction with ρ* = −12.6, indicating that the electron‐donating groups enhance the reaction rate. An isokinetic relationship is observed with β = 350 K, indicating that enthalpy factors control the reaction rate. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 776–783, 2000     

Poptube approach for ultrafast carbon nanotube growth

Microwave irradiation can be used to heat conductive materials and metallocene precursors to initiate ultrafast CNT growth. It takes only 15-30 seconds to grow CNTs at room temperature in air, without the need for any inert gas protection and additional feed stock gases.     

On the behaviour of Er3+ ion in tetragonal crystalline field

Crystal field parameters for ErGaG and Er³⁺ YAlG and used to compute the temperature dependence of Schottky specific heat, paramagnetic susceptibility, magnetic anisotropy,μ _eff and quadrupole splitting in the range 10–400 K. The hyperfine interaction parametersA andB for¹⁶⁶Er and¹⁶⁷Er in both the systems are also obtained and in turn used to estimate the nuclear specific heat contribution. The studied parameters compare well with the available experimental results.     

Crystal field in the rare earth hydroxides. Model calculations

The crystalline fields in concentrated as well as dilute rare-earth hydroxides are discussed in the light of theoretical models using recent crystallographic data.