89 research outputs found
Stainless steel-FRCM system for strengthening of RC beams: towards a sustainable strengthening technique
Fabric-Reinforced Cementitious Matrix (FRCM) systems for strengthening concrete structures are an alternative to traditional techniques. The FRCM system is a composite material consisting of two or more layers of cement-based matrix reinforced with dry fibres in the form of open mesh or fabric. When adhered to concrete structural members the FRCM system acts as supplemental external reinforcement. Many existing Reinforced Concrete (RC) members exhibit degradation due to the carbonation of concrete and/or corrosion of internal reinforcing steel bars. These RC members can be strengthened using stainless steel, in strip format (unidirectional fibres), embedded in a cementitious based matrix. The system, named Stainless Steel-FRCM, can be applied according to the Externally Bonded (EB) technique. In order to reduce times and costs of intervention, number of used materials, as well as the amount of chemical compounds, a novel Inhibiting-Repairing-Strengthening (IRS) technique is proposed and experimentally tested. Using a suitable matrix (thixotropic mortar with passivation properties) the main three operations of steel bars corrosion inhibition/protection, restoring of deteriorated concrete, and installation of the external strengthening can be carried out in one-step. For evaluating the effectiveness of both new strengthening system and installation technique an extensive experimental investigation was planned and developed. A part of the experimental research includes two groups of three RC beams (3.00 m and 4.80 m long): one strengthened withIRS technique, one strengthened with EB technique and one control beam. These beams were tested under monotonic loading. Further two beams, one beam for each group, strengthened according to IRS technique, were also tested under cyclic loading. The experimental results show the validity of the proposed solution in terms of structural performance and environmental sustainability
FRP-RC/PC members subjected to combined actions
The capacity provisions of conventional Reinforced Concrete (RC) and Prestressed Concrete (PC) beams subjected to combined action of torsion, shear and flexure are well known and stated by international/national codes. Similar provisions lack for concrete members containing Fibre Reinforced Polymer (FRP) reinforcements. In general, there is paucity of research on the treatment of torsion combined with other stress resultants for FRP-RC/PC members. In this paper the theoretical method proposed by the Canadian standard CSA S806 for FRP-RC/PC structures is presented. The critical issues, related to this topic, such as the appropriate strength and inclination of the diagonal struts and failure criteria are critically analyzed and addressed. In order to assess the reliability of this study a comparison between available experimental data regarding FRP-RC/PC beams subjected to combined actions and their corresponding theoretical provisions derived by the CSA S806 standard is shown. Furthermore, another approach, available in literature, which is based on the space truss model, is examined and used for comparison in order to evaluate the theoretical provisions offered by this model against the tests value of the set of the beams analyzed in this study. Based on the critical analysis of the results, it can be highlighted that the CSA method is able to conservatively predict the capacity of these beams
A Chemical Transport Model Emulator for the Interactive Evaluation of Mercury Emission Reduction Scenarios
Implementation of the Minamata Convention on Mercury requires all parties to "control, and where feasible, reduce" mercury (Hg) emissions from a convention-specified set of sources. However, the convention does not specify the extent of the measures to be adopted, which may only be analysed by decision-makers using modelled scenarios. Currently, the numerical models available to study the Hg atmospheric cycle require significant expertise and high-end hardware, with results which are generally available on a time frame of days to weeks. In this work we present HERMES, a statistical emulator built on the output of a global Chemical Transport Model (CTM) for Hg (ECHMERIT), to simulate changes in anthropogenic Hg (Hganthr) deposition fluxes in a source-receptor framework, due to perturbations to Hganthr emissions and the associated statistical significance of the changes. The HERMES emulator enables stakeholders to evaluate the implementation of different Hganthr emission scenarios in an interactive and real-time manner, simulating the application of the different Best Available Technologies. HERMES provides the scientific soundness of a full CTM numerical framework in an interactive and user-friendly spreadsheet, without the necessity for specific training or formation and is a first step towards a more comprehensive, and integrated, decision support system to aid decision-makers in the implementation of the Minamata Convention
The GOS4M Knowledge Hub: A web-based effectiveness evaluation platform in support of the Minamata Convention on Mercury
Abstract The Minamata Convention on Mercury was established to reduce the pressure on the environment caused by mercury by significantly reducing its emissions from anthropogenic activities. However, knowledge gaps still exist concerning emission inventories, emission factors and their integration in modelling frameworks. In addition, tools to facilitate communication between decision-makers and research groups providing measurement and modelling data are still scarce. This work presents the GOS4M Knowledge Hub, a public web application that provides an interactive and user friendly experience to access state-of-the-art modelling tools and data available in the literature. The Knowledge Hub currently integrates a Chemical Transport Model emulator, HERMES, coupled with a biogeochemical model, although it has been designed to house and deploy any number of different modelling components. Using the integrated dashboard, non-experts can perturb mercury releases from different anthropogenic emission sectors, simulating, for example, the application of Best Available Technologies, and then visualise in real-time the short- and long-term effects of the consequent reductions within a source-receptor framework. The dashboard also furnishes an estimate of the statistical significance of the changes in the model results. The analysis of a set of anthropogenic Hg emission reduction scenarios shows how an internationally coordinated effort would be necessary to achieve significant policy goals. It is important to note that the GOS4M Knowledge Hub yields the analysis presented here in a matter of seconds, compared to the days or weeks required by traditional modelling tools
Single-lap shear bond tests on Steel Reinforced Geopolymeric Matrix-concrete joints
YesNowadays Fiber Reinforced Polymers (FRPs) represent a well-established technique for rehabilitation of Reinforced Concrete (RC) and masonry structures. However, the severe degradation of mechanical properties of FRP under high temperature and fire as well as poor sustainability represents major weak points of organic-based systems. The use of eco-friendly inorganic geopolymeric matrices, alternative to the polymeric resins, would be highly desirable to overcome these issues. The present work aims to investigate the bond characteristic of a novel Steel Reinforced Geopolymeric Matrix (SRGM) strengthening system externally bonded to a concrete substrate having low mechanical properties. SRGM composite material consists of stainless steel cords embedded into a fireproof geopolymeric matrix. Single-lap shear tests by varying the bonded length were carried out. The main failure mode observed of SRGM-concrete joints was debonding at the fiber-matrix interface. Test results also suggest the effective bond length. On the basis of the experimental results, a cohesive bond-slip law was proposed.Part of the analyses were developed within the activities of Rete dei Laboratori Universitari di Ingegneria Sismica (ReLUIS) for the research program funded by the Dipartimento di Protezione Civile (DPC), Progetto DPC/ReLUIS 2016–AQ DPC/ReLUIS 2014–2016
An Assessment of Stratospheric Intrusions in Italian Mountain Regions Using STEFLUX
The Mediterranean basin is considered a global hot-spot region for climate change and air quality, especially concerning summer-time ozone (O3). Previous investigations indicated that the Mediterranean basin is a preferred region for stratosphere-to-troposphere exchange (STE) and deep stratospheric intrusion (SI) events. The Lagrangian tool STEFLUX, based on a STE climatology that uses the ERA Interim data, was hereby used to diagnose the occurrence of deep SI events in four mountain regions over the Italian peninsula, spanning from the Alpine region to the southern Apennines. By using near-surface O3 and relative humidity (RH) observations at three high-mountain observatories, we investigated the performance of STEFLUX in detecting deep SI events. Both experimental and STEFLUX detections agreed in describing the seasonal cycle of SI occurrence. Moreover, STEFLUX showed skills in detecting "long-lasting" SI events, especially in the Alps and in the northern Apennines. By using STEFLUX, we found positive tendencies in the SI occurrence during 1979–2017. However, in contrast to similar studies carried out in the Alpine region, the negative long-term (1996–2016) trend of O3 in the northern Apennines did not appear to be related to the SI's variability
Coexistence of Vagus Nerve Stimulation and Epicardial Implantable Cardioverter-Defibrillator System, Possible Interference: A Case Report and Systematic Review of the Literature
Vagus nerve stimulation (VNS) is an effective treatment for drug-resistant epilepsies in adults [1] and children [2]. Although VNS is generally well tolerated, rare cases of severe bradycardia..
translational challenges from the 2014 gastrointestinal cancers symposium toward a true tailored therapy through effective research
Gastrointestinal Cancers Symposium 2014, San Francisco, CA, USA, 16–18 January 2014 The Gastrointestinal Cancers Symposium represents an indisputable occasion for sharing results and research opportunities for investigators around the globe. Across the years along with clinical trials presentations the meeting increasingly acquired a distinct role as a scientific arena for translational research. Also, this year the need for predictive markers for first-generation targeted agents and research about novel biologically driven therapeutic options characterized most of the studies presented. We focus here on reports from the 2014 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium indicating an opportunity for biological selection of either the pharmacological target or the patient population in order to enhance clinical outcome
Successful ventricular tachycardia radioablation in a patient with previous chemical pleurodesis: A case report
IntroductionStereotactic arrhythmia radioablation (STAR) is a novel technique for the ablation of ventricular tachycardia in patients with contraindications to standard procedures, i.e., radiofrequency ablation.Case presentationWe report the case of a 73-year-old man with non-ischemic dilated cardiomyopathy and recurrent VT episodes. Electroanatomic mapping showed VT prevalently of epicardial origin, but direct epicardial access through subxyphoid puncture could not be performed due to pleuropericardial adhesions from a past history of chemical pleurodesis. STAR was performed, with no VT recurrence at 6 months follow-up.ConclusionsPrevious experiences with STAR have demonstrated its importance in the management of patients with refractory VT in whom other ablation strategies were not successful. Our case report highlights the use of STAR as a second choice in a patient with an unfavorable VT anatomical location and technical limitations to an optimal radiofrequency ablation. Moreover, it confirms STAR's effectiveness in the ablation of complex transmural lesions, which are more often associated with non-ischemic structural heart disease
Increasing the maturity of measurements of essential climate variables (ECVs) at Italian atmospheric WMO/GAW observatories by implementing automated data elaboration chains
In the framework of the National Project of Interest NextData, we developed automatic procedures for the flagging and formatting of trace gases, atmospheric aerosols and meteorological data to be submitted to the World Data Centers (WDCs) of the Global Atmosphere Watch program of the World Meteorological Organization (WMO/GAW). In particular, the atmospheric Essential Climate Variables (ECVs) covered in this work are observations of near-surface trace gas concentrations, aerosol properties and meteorological variables, which are under the umbrella of the World Data Center for Greenhouse Gases (WDCGG), the World Data Center for Reactive Gases, and the World Data Center for Aerosol (WDCRG and WDCA). We developed an overarching processing chain to create a number of data products (data files and reports) starting from the raw data, finally contributing to increase the maturity of these measurements. To this aim, we implemented specific routines for data filtering, flagging, format harmonization, and creation of data products, useful for detecting instrumental problems, particular atmospheric events and quick data dissemination towards stakeholders or citizens. Currently, the automatic data processing is active for a subset of ECVs at 5 measurement sites in Italy. The system represents a valuable tool to facilitate data originators towards a more efficient data production. Our effort is expected to accelerate the process of data submission to WMO/GAW or to other reference data centers or repositories. Moreover, the adoption of automatic procedures for data flagging and data correction allows to keep track of the process that led to the final validated data, and makes data evaluation and revisions more efficient by improving the traceability of the data production process
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