A Functional and Lagrangian Formulation of Two-Dimensional Topological Gravity

We reconsider two-dimensional topological gravity in a functional and lagrangian framework. We derive its Slavnov-Taylor identities and discuss its (in)dependence on the background gauge. Correlators of reparamerization invariant observables are shown to be globally defined forms on moduli space. The potential obstruction to their gauge-independence is the non-triviality of the line bundle on moduli space ${\cal L}_x$, whose first Chern-class is associated to the topological invariants of Mumford, Morita and Miller. Based on talks given at the Fubini Fest, Torino, 24-26 February 1994, and at the Workshop on String Theory, Trieste, 20-22 April 1994.Comment: 11 pages, harvmac, CERN-TH-7302/94, GEF-Th-6/199

Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge

This paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge

LCA of Zero Valent Iron Nanoparticles Encapsulated in Algal Biomass for Polishing Treated Effluents

Research data produced within the CARIPLO IMAP and Perform Water 2030 projects were processed using the SimaPro software to carry out the Life Cycle Assessment according to ISO 14040-44 of an innovative process of treated effluents' polishing. The study aims to evaluate the integration of a microalgae culture as a side-stream process into the baseline layout of a wastewater treatment plant to remove nitrogen from the supernatant of sludge centrifugation from an environmental perspective. In particular, the investigated system focuses on using the algal biomass produced as an organic matrix for encapsulating zero-valent iron nanoparticles to be used for the final refinement of the effluent. Zero-valent iron (ZVI) is a reactive metal and an effective reducing agent. It can be used to remove organic and inorganic pollutants (e.g., chlorinated organics, pharmaceuticals, metals, textile dyestuffs). The encapsulation of ZVI by hydrothermal carbonization (HTC) in a carbonaceous matrix allows for overcoming the problems related to its lack of stability, easy aggregation, and difficulty in separating the ZVI nanoparticles from the treated solution. The case study refers to Bresso wastewater treatment plant (Milan province, Northern Italy). The environmental performances of the study were assessed following the Life Cycle Impact Assessment methods IMPACT 2002+. According to the results, the new process integration does not affect the environmental performance of the WWTP, still implying a significant improvement in the removal of metals and micropollutants. In fact, due to the ability of ZVI nanoparticles to remove organic and inorganic pollutants, the outflowing load will be significantly reduced, which will improve the environmental performance of the entire Bresso wastewater treatment plant

Application of martensitic SMA alloys as passive dampers of GFRP laminated composites

This paper describes the application of SMA (Shape Memory Alloy) materials to enhance the passive damping of GFRP (Glass Fiber Reinforced Plastic) laminated composite. The SMA has been embedded as reinforcement in the GFRP laminated composite and a SMA/GFRP hybrid composite has been obtained. Two SMA alloys have been studied as reinforcement and characterized by thermo-mechanical tests. The architecture of the hybrid composite has been numerically optimized in order to enhance the structural damping of the host GFRP laminated, without significant changes of the specific weight and of the flexural stiffness. The design and the resultant high damping material are interesting and will be useful in general for applications related to passive damping. The application to a new designed lateral horn of railway collector of the Italian high speed trains is discussed

Large Deviation Approach to the Randomly Forced Navier-Stokes Equation

The random forced Navier-Stokes equation can be obtained as a variational problem of a proper action. By virtue of incompressibility, the integration over transverse components of the fields allows to cast the action in the form of a large deviation functional. Since the hydrodynamic operator is nonlinear, the functional integral yielding the statistics of fluctuations can be practically computed by linearizing around a physical solution of the hydrodynamic equation. We show that this procedure yields the dimensional scaling predicted by K41 theory at the lowest perturbative order, where the perturbation parameter is the inverse Reynolds number. Moreover, an explicit expression of the prefactor of the scaling law is obtained.Comment: 24 page

A PRELIMINARY FEASIBILITY ANALYSIS ABOUT THE STRUCTURAL HEALTH MONITORING OF RAILWAY CONCRETE SLEEPERS BY ACOUSTIC EMISSION AND DIGITAL IMAGE CORRELATION

Railway concrete sleepers are made out of steel reinforced concrete and are a safety critical component of the railway track. Different kinds of failure are observed during service and this requires a maintenance plan involving non-destructive testing. Nevertheless, shifting from a non-destructive approach to structural health monitoring has shown relevant opportunities to increase in-service reliability and to decrease the costs of maintenance. From this point of view, the present paper describes a preliminary feasibility analysis about the application of acoustic emission for detection of cracks in prestressed concrete sleepers. For the purpose of assessment, obtained results are compared with other methods, such as digital image correlation and visual testing. Encouraging results indicate the possibility to carry out more validating tests in order to get the engineering of a suitably cheap monitoring system for in-service applications

Double-Stranded RNA Targeting Dicer-Like Genes Compromises the Pathogenicity of Plasmopara viticola on Grapevine

Downy mildew caused by Plasmopara viticola is one of the most devastating diseases of grapevine, attacking all green parts of the plant. The damage is severe when the infection at flowering stage is left uncontrolled. P. viticola management consumes a significant amount of classical pesticides applied in vineyards, requiring efficient and environmentally safe disease management options. Spray-induced gene silencing (SIGS), through the application of exogenous double-stranded RNA (dsRNA), has shown promising results for the management of diseases in crops. Here, we developed and tested the potential of dsRNA targeting P. viticola Dicer-like (DCL) genes for SIGS-based crop protection strategy. The exogenous application of PvDCL1/2 dsRNA, a chimera of PvDCL1 and PvDCL2, highly affected the virulence of P. viticola. The reduced expression level of PvDCL1 and PvDCL2 transcripts in infected leaves, treated with PvDCL1/2 dsRNA, was an indication of an active RNA interference mechanism inside the pathogen to compromise its virulence. Besides the protective property, the PvDCL1/2 dsRNA also exhibited a curative role by reducing the disease progress rate of already established infection. Our data provide a promising future for PvDCL1/2 dsRNA as a new generation of RNA-based resistant plants or RNA-based agrochemical for the management of downy mildew disease in grapevine