Room temperature Cl(2) sensing using thick nanoporous films of Sb-doped SnO(2)

Thick film resistive Cl(2) sensors were fabricated using SnO(2) doped with Sb. The nanocrystalline powders of Sb-doped SnO(2) synthesized by a sol-gel method were compressed into an 800?μm thick pellet. The fabricated sensors were tested against gases like Cl(2), Br(2), HCl, NO, NO(2), CHCl(3), NH(3) and H(2). The highest response to Cl(2) was achieved in 0.1% Sb doping where an exposure to 3?ppm of Cl(2) gas led to a 500-fold increase in device resistance. The high sensitivity to Cl(2) is accompanied by minor interference due to other gases at room temperature. It was found that the SnO(2) doped with 0.1% Sb exhibited high response, selectivity (>100 in comparison to the gases described above) and short response time (～60?s) to Cl(2) at 3?ppm level at room temperature.     

Enabling autonomicity in wireless mesh networks with the ETSI AFI GANA reference model

The distributed nature of wireless mesh networks (WMNs) allows them to benefit from multiple autonomic functionalities. However, the existing landscape of self‐x solutions (eg, self‐configuration) is fragmented and the lack of a standardized framework through which interoperable autonomics can be developed has been hampering adoption and deployment of autonomics in real‐world service networks. There is a need for a standardized architectural framework that enables to comprehensively support and integrate interoperable components for autonomicity in WMNs. Such an architecture (autonomicity‐enabled wireless mesh architecture) is currently being standardized by the working group called Evolution of Management towards Autonomic Future Internet (AFI) in the European Telecommunications Standards Institute within the Network Technologies Technical Committee. The proposed autonomic wireless mesh architecture is an instantiation of the AFI GANA (Generic Autonomic Network Architecture) reference model, a standards‐based approach to autonomics. This paper complements and extends the early version of the architecture by further detailing the architectural principles and providing experimental and validation results. First, we provide a brief overview of the AFI GANA reference model and then show how each of its building blocks can be instantiated for WMNs. We evaluate the proposed architecture by implementing and testing the 4 basic self‐x functionalities defined by the GANA model. The provided guidelines can now help researchers and engineers build autonomicity‐enabled WMNs using a standardized framework that enables adoption and deployment of autonomics by industry, thereby enabling researchers and engineers to contribute to the further evolution of the standard in the European Telecommunications Standards Institute.     

UniFAFF: a unified framework for implementing autonomic fault management and failure detection for self‐managing networks

Today's network management, as known within the Fault, Configuration, Accounting, Performance, Security (FCAPS) management framework, is moving towards the definition and implementation of ‘self‐managing’ network functions, with the aim of eliminating or drastically reducing human intervention in some of the complex aspects or daunting tasks of network management. The fault management plane of the FCAPS framework deals with the following functions: fault detection, fault diagnosis, localization or isolation, and fault removal. Task automation is at the very heart of self‐managing (autonomic) nodes and networks, meaning that all functions and processes related to fault management must be automated as much as possible within the functionalities of self‐managing (autonomic) nodes and networks, in order for us to talk about autonomic fault management. At this point in time there are projects calling for implementing new network architectures that are flexible to support on‐demand functional composition for context‐ or situation‐aware networking. A number of such projects have started, under the umbrella of the so‐called clean‐slate network designs. Therefore, this calls for open frameworks for implementing self‐managing (autonomic) functions across each of the traditional FCAPS management planes. This paper presents a unified framework for implementing autonomic fault management and failure detection for self‐managing networks, a framework we are calling UniFAFF. Copyright © 2008 John Wiley & Sons, Ltd.     

Adsorption kinetics, isotherms and thermodynamics of atrazine removal using a banana peel based sorbent

Atrazine removal from water by treated banana peels was studied. The effect of pH, contact time, initial atrazine concentration, and temperature were investigated. Batch experiments demonstrated that 15 g L(-1) adsorbent dosage removed 90-99% of atrazine from 1-150 ppm aqueous solutions. The removal was both pH and temperature dependent with the most atrazine removed between pH 7 and 8.2 and increased with increasing temperature. Equilibrium data fitted well to the Langmuir and Redlich-Peterson models in the concentration and temperature ranges investigated, with a maximum adsorption capacity of 14 mg g(-1). Simple mass transfer models were applied to the experimental data to examine the adsorption mechanism and it was found that both external mass transfer and intraparticle diffusion played important roles in the adsorption mechanisms. The enthalpy of atrazine adsorption was evaluated to be 67.8 ± 6.3 kJ mol(-l) with a Gibbs free energy of -5.7 ± 1.2 kJ mol(-1).