227 research outputs found
Mechanical performance of epoxy coated AR-glass fabric Textile Reinforced Mortar: Influence of coating thickness and formulation
No full textThe mechanical performance of epoxy coated AR-glass fabric reinforced composite is investigated. A three-stage manufacturing process is considered, which involves fabric surface functionalization, liquid coating deposition and long-term setting and finally fabric embedment in the mortar matrix. Two epoxy coatings are considered, which only differ by the hardening agent. However, coating thickness is significantly diverse as a result of modified viscosity during liquid deposition. Performance is assessed in uni-axial tension as well as in three-point bending and it is expressed in terms of strength curves, data dispersion, crack pattern and failure mechanism. Remarkably, despite being very similar, the analyzed coatings produce a significantly different performance, especially when data dispersion is incorporated and design limits are considered. Indeed, although both coatings are able to consistently deliver fabric rupture at failure, only the thinnest is associated with small data scattering and an almost plastic post-peak behavior in bending. The associated design elongation limit reaches the maximum allowed value according to the ICC guidelines. In fact, it appears that coating thickness plays a crucial role in determining mechanical performance and fabric flexibility. The proposed manufacturing process proves extremely effective at enhancing matrix-to-fabric adhesion and thereby prevent telescopic failure
Sulla natura risarcitoria di danno emergente dell'indennità erogata per prestazione lavorativa svolta oltre l'orario massimo di lavoro
No full textTra flessibilità e regole: un primo bilancio della legislatura
No full textIl saggio discute l'evoluzione dell'economia italiana e in particolare della finanza pubblica nel corso della legislatura 2013-2017 (effetti delle principali interventi in termini di imposte e spese). Si dà particolare enfasi ai vincoli fiscali definiti a livello europeo e la "fiscal stance" viene valutata anche in termini comparati con gli altri paesi dell'eurozona
Authoring the 'Intelligence' of an Educational Game
No full textIn this paper, we describe a frame-based production rules system that works ad the Artificial intelligence Engine of an educational computer game. We discuss the need of an authoring environment clearly separated by the game in order to allow a technical staff without any skills in either AI or Computer Science to encode the intelligence of the game. Finally, we briefly introduce two graphical interfaces for authoring and testing frame hierarchies and production rules. The production rule system and the authoring tool have been developed in the context of a project funded by the European Community to develop a prototypical educational computer gam
Some remarks on the coincidence set for the Signorini problem
No full textWe study some properties of the coincidence set for the boundary Signorini problem, improving some results from previous works by the second author and collaborators. Among other new results, we show here that the convexity assumption on the domain made previously in the literature on the location of the coincidence set can be avoided under suitable alternative conditions on the data
New sol-gel materials for high energy applications in nonlinear optics
No full textOrganic-inorganic hybrid materials, composed of inorganic oxide structures and interpenetrated cross-linked organic polymers, are promising candidates for electro/optical applications, combining the most important glasslike and
polymerlike properties. This is particularly true when large laser power density is used: these materials show high laser
damage resistance compared with that of polymeric systems.
A deep study of effects and causes of laser damage has never been done, especially for hybrid materials. The
mechanisms of optical damage depend on different factors like laser experimental parameters, such as pulse duration,
beam size and wavelength, or the microstructural characteristics and defects of the material.
Hybrid materials possessing desired shapes and optical and mechanical properties are well synthesized by the sol-gel
technique. The use of Glycidoxypropyltrimethoxysilane (GPTMS) allows preparing heterogeneous and resistant
materials, with good optical properties.
Different sol-gel matrices have been prepared in order to study their laser damage resistance. The possibility of varying
the catalysts and precursors or the synthesis protocol allows obtaining materials with similar chemical composition and
different microscopical properties. By this way, it is possible to study the laser damage threshold of these samples and to
find the way to enhance and optimize the laser damage resistance, useful in non-linear optical devices
Laser damage of glycidoxypropyltrimethoxysilane based hybrid materials
No full textThe preparation of solid samples, having specific optical properties, is one of the main goals for the realization of devices in the photonic
field. To this end, it is important to attain the best control of the optical properties in the final materials. The sol–gel technique is a
powerful synthesis method allowing the preparation of matrices with high stability, mechanical resistance and high optical quality. The
use of hybrid organic–inorganic precursors permits samples with different thicknesses, ranging from films of hundreds of nanometers to
bulk samples of millimeters, to be obtained. The control of the synthesis protocol and the choice of precursors and catalyst allows the
control of the final matrix microstructure, which is related to optical properties, like the laser damage threshold. In this work four different
matrices, based on glycidoxypropyltrimethoxysilane and Zr alcoxide, have been prepared through sol–gel synthesis. An interpenetrating
organic and inorganic network, controlled by the synthesis protocol, characterizes these matrices. The obtained materials show
high resistance to the optical damage and long term stability
Sul S. Pantaleo 8 della Biblioteca Nazionale Centrale di Roma: una miscellanea dantesca di metà Trecento
No full textThe article discusses the MS S. Pantaleo 8, a remarkable collection of Dante’s works now
kept at the Biblioteca Nazionale Centrale in Rome. By investigating how the manuscript
was prepared, and on the basis of the eight different writings of the scribes who copied
the texts, as well as of the work of the three illuminators involved in the decoration of the
book, the author suggests that the manuscript might have been copied around the mid-14th
century either in eastern Tuscany or in Umbria
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