SERVICES,SEMANTICS, AND STANDARDS: ELEMENTS OF A LEARNING GRID INFRASTRUCTURE

There has been considerable political pressure and much hope invested in the use of communication and information technologies to provide wider access to education, while improving quality and reducing costs. Unfortunately, many of the responses to the challenge of these aspirations have consisted of simple Web technology-driven products, which have failed to progress effective learning. In this paper we outline the characteristics and pedagogical goals of a learning paradigm that is used to drive the technical requirements, rather than being constrained by what is easily achieved in XHTML. We identify and explain the key roles played by services, semantics, and standards in meeting pedagogical goals of novel learning situations, and illustrate with some scenarios that build bridges between traditional learning contexts and future possibilities. Crucially, we explain why we have adopted Grid technologies in the European Learning Grid Infrastructure (ELeGI) research program.     

Stability of Nonlinear Differential-Algebraic Systems Via Additive Identity

The stability analysis for nonlinear differential-algebraic systems is addressed using tools from classical control theory. Sufficient stability conditions relying on matrix inequalities are established via Lyapunov Direct Method. In addition, a novel interpretation of differential-algebraic systems as feedback interconnection of a purely differential system and an algebraic system allows reducing the stability analysis to a small-gain-like condition. The study of stability properties for constrained mechanical systems, for a class of Lipschitz differential-algebraic systems and for an academic example is used to illustrate the theory.      

Optimal wind turbines placement within a distribution market environment

This paper proposes a hybrid optimization method for optimal allocation of wind turbines (WTs) that combines genetic algorithm (GA) and market-based optimal power flow (OPF). The method jointly maximizes net present value (NPV) related to WTs investment made by WTs’ developers and social welfare (SW) considering different combinations of wind generation and load demand over a year. The GA is used to choose the optimal size while the market-based OPF to determine the optimal number of WTs at each candidate bus. The stochastic nature of both load demand and wind power generation is modeled by hourly time series analysis. The effectiveness of the method is demonstrated with an 84-bus 11.4 kV radial distribution system.     

The Italian academic community’s electronic voting system

A new Italian law regarding the recruitment of university researchers and teaching staff provides for election, on a national basis, of the members of the selection committees. In order to handle such a process, an electronic voting system has been developed which offers the necessary guarantees in terms of legitimacy, security, anonymity and secrecy both in the voting process and in the scrutiny. The system presented is based on standard cryptographic algorithms and has been in use by all Italian universities since June 1999.     

Are Electrospun Fibrous Membranes Relevant Electrode Materials for Li‐Ion Batteries? The Case of the C/Ge/GeO2 Composite Fibers

Self‐supporting paper‐like membranes consisting of carbon/germanium dioxide (C/GeO₂) fibers are prepared via electrospinning of solutions with different germanium load (2.50?4.25 wt%), followed by carbonization at 550?700 °C, and are evaluated as anode materials in lithium ion batteries. The investigation of the physicochemical properties of the membranes by several characterization techniques shows that, as expected, with increasing carbonization temperature better graphitized and less nitrogen‐rich C fibers are obtained, containing Ge⁰ and/or reduced oxide phases along with GeO₂ nanoparticles. These characteristics, combined with the cold pressing of the as‐spun membrane that noticeably reduces the hollow space within the fibres giving rise to a more compact and tight structure, lead to initial discharge volumetric capacities (≈1390–3580 mAh cm^?3) much higher than commercial graphite anodes. In particular, the membrane prepared from solution with 4.25 wt% Ge‐load by cold‐pressing and carbonization at 700 °C, is able to deliver ≈1500 mAh cm^?3 after 50 cycles at 50 mA g^?1 with a Coulombic efficiency close to 100%. Nevertheless, the anodes exhibit poor rate capability. This is because the carbonization at high temperature promotes outward diffusion and subsequent coalescence of Ge‐clusters in larger particles, with the structure of the fibers made fragile by the formation of voids within them.     

Separation and purification of functionalised water-soluble multi-walled carbon nanotubes by flow field-flow fractionation

Water-soluble, functionalised multi-walled carbon nanotubes (MWNT) have been separated and purified from amorphous material through direct flow field-flow fractionation. MWNT subpopulations of relatively homogeneous, different length were obtained by collecting fractions of the raw, highly polydispersed (200-5000 nm) functionalised MWNT sample.     

Biomarker discovery in asthma and COPD by proteomic approaches

Asthma and chronic obstructive pulmonary disease (COPD) are multifactorial respiratory diseases, characterized by reversible and irreversible airway obstruction, respectively. Even if the primary causes of these diseases remain unknown, inflammation is a central feature that leads to progressive and permanent pulmonary tissue damage (airway remodeling) up to the total loss of lung function. Therefore, the elucidation of the inflammation mechanisms and the characterization of the biological pathways, involved in asthma and COPD pathogenesis, are relevant in finding new possible diagnostic/prognostic biomarkers and for the validation of new drug targets. In this context, current advances in proteomic approaches, especially those based on MS, provide new tools to facilitate the discovery-driven studies of new biomarkers in respiratory diseases and improve the clinical reliability of the next generation of biomarkers for these diseases consisting of multiple phenotypes. This review will report an overview of the current proteomic methods applied to the discovery of candidate biomarkers for asthma and COPD, giving a special emphasis to emerging MS-based techniques.     

Corrosion protection of AA6061 T6-10 % Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composite by molybdate conversion coatings

The corrosion protection performance of aluminum composite materials was investigated in 3.5% NaCl solution for time ranging between 1–60 days. Series of specimens were treated in molybdate solutions under different conditions. Free immersion and electrochemical activation techniques were used to apply the molybdate layer. The specimens which were directly treated or pickled before molybdate treatment showed severe pitting corrosion. Conversely, the specimens which were subjected to an oxide thickening step before the molybdate treatment showed outstanding corrosion protection. XPS revealed a higher amount of molybdate as MoO₄^2– for the specimens prepared by electrochemical activation technique than for the free immersion technique.     

Synthesis of alcohols from carbon oxides and hydrogen on ZnCrTi oxides: preparation and catalytic activity

Ternary systems of composition (1–x)ZnCrO_2.5·xZn₂TiO₄ were tested in the synthesis of higher alcohols from syngas. The catalysts after calcination were found to be solid solutions of Zn, Cr and Ti oxides of spinel like structure, with only a small amount of crystalline ZnO phase segregated. After the catalytic test more important quantities of crystalline ZnO were formed in the catalysts revealing an intrinsic instability of the system. However, a significant maximum in selectivity to higher alcohols was found forx = 0.1 and is associated with an increased rate of isobutanol (2-methylpropanol) formation observed on this system.     

Reinforcement delamination of metallic beams strengthened by FRP strips: Fracture mechanics based approach

The delamination failure of metallic beams reinforced by externally bonded fibres reinforced polymers (FRP) is addressed in this paper and a simplified fracture mechanics based approach for the edge delamination of the reinforcement strips is illustrated. The criterion is based on the evaluation of the energy release rate (ERR) using both analytical and numerical models. The analytical models consist of a simplified version of a “two parameters elastic foundation” and “transformed section” model while the numerical analyses refer to the modified virtual crack closure technique (MVCCT). The main aim of the paper is to establish a fracture mechanics failure criterion based on the ERR and the specific fracture energy of the bonded strips. The criterion is an alternative approach to the well known stress based method to asses the load carrying capacity of the adhesive joint. The accuracy of the simplified approaches is shown through a numerical example which refers to a steel beam strengthened by carbon fibres reinforced polymers (CFRP).