Search results for " DEGRADATION"

showing 10 items of 510 documents

SHEAR STRENGTH DEGRADATION DUE TO FLEXURAL DUCTILITY DEMAND IN R.C. ELEMENTS

2014

A proposal is formulated that allows to evaluate the residual shear strength of reinforced concrete columns and beams for an assigned flexural ductility demand by limiting the range of the deviation angle between the inclinations of the yield  and the crack lines. In order to take into account the degradation due to cyclic loads, the reduction of the range of the deviation angle is related to the value of cinematic ductility

Settore ICAR/09 - Tecnica Delle Costruzionishear strength; Ductility; degradation; cyclic loadscyclic loadsshear strength ductility degradation cyclic loads.shear strengthDuctilitydegradation
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Sistemazione in situ o musealizzazione dei frammenti architettonici: problemi di conservazione dopo il terremoto di Messina del 1908

2012

After the big earthquake of Messina in 1908, a lot of important fragments of the ancient city, coming from destroyed palaces and churches, were transported in a open space near the ancient church of SS. Salvatore, where in an old silk factory was born the actual Regional Museum of Messina. The arrangement of those elements - as Marble sculptures, big fragments of architectural decorations, stone portals - was long debated and different architects, art historians and archaeologists produced ideas and projects about the costruction of a new museum and the arrangement in open space of many fragments, so important to maintaining the memory of the ancient city of Messina, destroyed by the earthq…

Settore ICAR/19 - RestauroEarthquake Messina architectural fragments degradation
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Environmental aging effects on high-performance biocomposites reinforced by sisal fibers

2023

Among the innovative materials, an important role is played by the so-called biocomposites, generally made by an eco-friendly matrix reinforced with natural fibers. Unfortunately, due to the degradability of the green matrixes as well as to hydrophilicity of the natural fibers, the resistance of such innovative materials to the environmental agents is, in general, relativity low, and it can significantly limit their use in outdoor conditions. To contribute to the knowledge of the effects of the leading environmental agents on the mechanical properties of highperformance biocomposites made of a green epoxy matrix reinforced by agave fibers, a systematic experimental testing campaign has been…

Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di MacchinePolymers and PlasticsMechanics of MaterialsMaterials ChemistryMechanical propertiesCondensed Matter PhysicsBiocompositeSisal fiberEnvironmental degradationPolymer Degradation and Stability
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Degradation od Mater-Bi/wood flour biocomposites in active sewage sludge

2009

Settore ING-IND/22 - Scienza E Tecnologia Dei MaterialiInjection mouldingExtrusionScanning Electron MicroscopyPolymer compositeEnvironmental degradation
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Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle

2022

The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…

Settore ING-IND/22 - Scienza E Tecnologia Dei MaterialiMechanics of MaterialsMechanical EngineeringCeramics and CompositesIndustrial and Manufacturing EngineeringEnvironmental degradation Hybrid composites Mechanical testing Moisture desorption Polymer-matrix composites (PMCs)
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Flax–Glass Fiber Reinforced Hybrid Composites Exposed to a Salt-Fog/Dry Cycle: A Simplified Approach to Predict Their Performance Recovery

2023

Despite natural fibers gaining significant attention in recent decades, their limited performance and poor durability under humid environments cannot allow them to fully replace their synthetic counterparts as reinforcement for structural composites. In such a context, this paper aims to investigate how exposure to a humid/dry cycle affects the mechanical response of epoxy laminates reinforced with flax and glass fibers. In particular, the main goal is to assess the performance evolution of a glass–flax hybridized stacking sequence in comparison with the full glass and flax fiber reinforced composites. To this end, the investigated composites were first exposed to salt-fog for 15 or 30 days…

Settore ING-IND/22 - Scienza E Tecnologia Dei Materialienvironmental degradation flax fibers forecasting modeling hybrid composites mechanical properties moisture sorption
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Graphite-supported TiO2 for 4-nitrophenol degradation in a photoelectrocatalytic reactor

2009

WOS: 000274769500044

Settore ING-IND/24 - Principi Di Ingegneria ChimicaAnataseMaterials scienceAqueous solutionScanning electron microscopePhotoelectrocatalytic degradation photoelectrocatalytic reactor graphite supported TiO2 4-nitropheol oxidationGeneral Chemical EngineeringContinuous reactorAnalytical chemistryGraphite-Supported Tio2General Chemistry4 Nitrophenol OxidationIndustrial and Manufacturing EngineeringAmorphous solidPhotoelectrocatalytic ReactorElectrodeEnvironmental ChemistrySettore CHIM/07 - Fondamenti Chimici Delle TecnologieGraphiteEnergy sourcePhotoeletrocatalytic DegradationChemical Engineering Journal
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Photocatalytic degradation of 4-nitrophenol in a continuous reactor containing titanium dioxide supported on glass beads

2008

WOS: 000258975200009

Settore ING-IND/24 - Principi Di Ingegneria ChimicaTitanium DioxideMaterials scienceContinuous reactor4-NitrophenolElectrochemistryContinuous PhotoreactorCatalysischemistry.chemical_compoundchemistryChemical engineering4-NitrophenolTitanium dioxideOxidationPhotocatalysis4-Nitrophenol Photocatalysis Oxidation Titanium dioxide Continuous photoreactorPhysical and Theoretical ChemistryPhotocatalysisPhotocatalytic degradationSelf-cleaning glass
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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An evaluation of recent local image descriptors for real-world applications of image matching

2019

This paper discusses and compares the best and most recent local descriptors, evaluating them on increasingly complex image matching tasks, encompassing planar and non-planar scenarios under severe viewpoint changes. This evaluation, aimed at assessing descriptor suitability for real-world applications, leverages the concept of approximated overlap error as a means to naturally extend to non-planar scenes the standard metric used for planar scenes. According to the evaluation results, most descriptors exhibit a gradual performance degradation in the transition from planar to non-planar scenes. The best descriptors are those capable of capturing well not only the local image context, but als…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniSettore INF/01 - InformaticaImage matchingComputer sciencebusiness.industryVisual descriptorsComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONPattern recognition02 engineering and technology03 medical and health sciences0302 clinical medicineLocal Image Descriptors; Image MatchingRobustness (computer science)Computer Science::Computer Vision and Pattern RecognitionComputer Science::Multimedia030221 ophthalmology & optometry0202 electrical engineering electronic engineering information engineering020201 artificial intelligence & image processingArtificial intelligencebusinessImage matching Data-driven approach Descriptors Evaluation results Local descriptors Local image descriptors Performance degradation Real-worldScene structure Computer vision
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