Study of the EFILE diagnostic under radiofrequency electric field

The electric field is a parameter of special relevance in plasma physics. Its fluctuations are responsible for various macroscopic phenomena, such as anomalous transport in fusion plasmas or plasma-wall interactions, and its measure is therefore required. At present, most diagnostic tools perturb the field (like Langmuir probes) or require multiple simultaneous measures to achieve a good spatial resolution (like spectroscopy and tomography). The EFILE diagnostic (Electric Field Induced Lyman-alpha Emission) is currently under development at PIIM laboratory at Aix-Marseille Université (France) and aims to provide a non intrusive and precise measurement of the electric field in the plasma edge region, using a beam of hydrogen atoms prepared in the metastable 2s state. The metastable particles are obtained by means of a proton beam extracted from a hydrogen plasma source, and neutralised by interaction with vaporised caesium. When a 2s atom enters a region where an electric field is present, it undergoes a transition to the 2p state (Stark mixing). It then quickly decays to the ground level, emitting Lyman-alpha radiation, which is collected by a photomultiplier. The 2s->2p transition rate is proportional to the square of the magnitude of the electric field, and depends on the field oscillation frequency (with peaks around 1 GHz). By measuring the intensity of the Lyman-alpha radiation emitted by the beam it is possible to determine the magnitude of the field in a defined region. In this work, an analysis of the behaviour of the diagnostic under static or radiofrequency electric field is presented. Electric field simulations obtained with a finite element solver of Maxwell equations, combined with theoretical calculations of the Stark mixing transition rate, are used to develop a model for the interpretation of photomultiplier data. This method shows good agreement with experimental results for the static field case, and allows to measure the field magnitude for the oscillating case. Issues linked to the experimental set-up and limits of the diagnostic itself are shown and possible design implementations are given.ope

in situ experimental tests on masonry panels strengthened with textile reinforced mortar composites

Abstract Textile Reinforced Mortar (TRM) composites are a retrofitting techniques used for strengthening masonry structures. The system is composed of dry fibers grids embedded in two layers of inorganic matrix. The paper describes the results of an in-situ experimental campaign on ancient masonry panels reinforced with different TRM systems. The tests were performed in a building located in Finale Emilia (north of Italy) built at the beginning of the last century. Four diagonal compressive tests were performed on unreinforced and reinforced walls. The walls were strengthened with different configurations: two panels were reinforced with a TRM systems composed of a lime mortar and two different types of glass fiber grids and twist steel bars used as anchors; one panel was reinforced with a layer of TRM on one side and a Near Surface Mounted (NSM) system on the other one. The results of the tests are described and a complete mechanical characterization of the reinforcement systems and of the masonry was performed to analyze the experimental results and validate simple analytical models

Ancient masonry arches and vaults strengthened with TRM, SRG and FRP composites: Numerical analyses

[EN] The two arches and the three vaults experimentally described in Carozzi et al. (2017) are here analyzed with a novel robust FE lower bound limit analysis code, suitable to predict active failure mechanisms, lines of thrust and collapse loads in absence and presence of TRM, SRG and FRP reinforcement. The approach relies into a discretization into rigid-infinitely resistant quadrilateral elements for masonry, interfaces between contiguous elements exhibiting limited strength and perfectly bonded rigid-plastic trusses representing the reinforcement. For masonry, a No Tension Material NTM model can be adopted to compare with classic Heyman¿s results, but also a limited compressive and tensile strength with a cohesive frictional behavior in shear may be accounted for in a relatively simple fashion, i.e. in principle with the possibility to model shear sliding and compression crushing. Debonding and delamination of the reinforcement are considered in a conventional way, assuming trusses with a limited tensile strength derived from either experimental data available or consolidated formulas from the literature. With the knowledge of the exact position of the hinges provided by limit analysis, 2D FE static analyses with non-linearity and softening concentrated exclusively on hinges are carried out, to simply extend the knowledge beyond collapse loads estimation towards a prediction of initial stiffness and ultimate displacements. In all cases, promising agreement with experiments is observed.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.Bertolesi, E.; Milani, G.; Carozzi, FG.; Poggi, C. (2018). Ancient masonry arches and vaults strengthened with TRM, SRG and FRP composites: Numerical analyses. Composite Structures. 187:385-402. https://doi.org/10.1016/j.compstruct.2017.12.021S38540218

Chest pain caused by multiple exostoses of the ribs: A case report and a review of literature

Abstract The aim of this paper is to report an exceptional case of multiple internal exostoses of the ribs in a young patient affected by multiple hereditary exostoses (MHE) coming to our observation for chest pain as the only symptom of an intra-thoracic localization. A 16 years old patient with familiar history of MHE came to our observation complaining a left-sided chest pain. This pain had increased in the last months with no correlation to a traumatic event. The computed tomography (CT) scan revealed the presence of three exostoses located on the left third, fourth and sixth ribs, all protruding into the thoracic cavity, directly in contact with visceral pleura. Moreover, the apex of the one located on the sixth rib revealed to be only 12 mm away from pericardium. Patient underwent video-assisted thoracoscopy with an additional 4-cm mini toracotomy approach. At the last 1-year followup, patient was very satisfied and no signs of recurrence or major complication had occured. In conclusion, chest pain could be the only symptom of an intra-thoracic exostoses localization, possibly leading to serious complications. Thoracic localization in MHE must be suspected when patients complain chest pain. A chest CT scan is indicated to confirm exostoses and to clarify relationship with surrounding structures. Video-assisted thoracoscopic surgery can be considered a valuable option for exostoses removal, alone or in addiction to a mini-thoracotomy approach, in order to reduce thoracotomy morbidity

new italian guidelines for design of externally bonded fabric reinforced cementitious matrix frcm systems for repair and strengthening of masonry and concrete structures

Abstract The paper summarizes the main features of a standardization activity carried out in Italy by the Ministry of Public Works, to which two of the authors have taken part, for the homologation and the acceptance of Fabric-Reinforced Cementitious Matrix (FRCM) composites. During the last years, such composite materials have becoming increseangly popular in the civil engineering field for strengthening existing constructions, even if difficulties can occur in their mechanical characterization that is strongly affected by different and complex failure mechanisms. The American ACI 549.4R-13 is currently the only available guideline for design and construction of these systems. In this framework, the paper describes the Italian proposals for the homologation process of FRCM materials as well as for the design of strengthening interventions with these composites. Comparisons with the American guideline are also reported together with some considerations regarding the different partial safety factors

Antioxidant Strategies and Respiratory Disease of the Preterm Newborn: An Update

Preterm newborns are challenged by an excessive oxidative burden, as a result of several perinatal stimuli, as intrauterine infections, resuscitation, mechanical ventilation, and postnatal complications, in the presence of immature antioxidant capacities. “Oxygen radical disease of neonatology” comprises a wide range of conditions sharing a common pathway of pathogenesis and includes bronchopulmonary dysplasia (BPD) and other main complications of prematurity. Antioxidant strategies may be beneficial in the prevention and treatment of oxidative stress- (OS-) related lung disease of the preterm newborn. Endotracheal supplementation or lung-targeted overexpression of superoxide dismutase was proved to reduce lung damage in several models; however, the supplementation in preterm newborn failed to reduce the risk of BPD, although long-term respiratory outcomes were improved. Also melatonin administration to small cohorts of preterm newborns suggested beneficial effects on lung OS. The possibility to identify single nucleotide polymorphism affecting the risk of BPD may help to identify specific populations with particularly high risk of OS-related diseases and may pose the basis for individually targeted treatments. Finally, surfactant replacement may lead to local anti-inflammatory and antioxidant effects, thanks to specific enzymatic and nonenzymatic antioxidants naturally present in animal surfactants

Case-specific parametric analysis as research-directing tool for analysis and design of GFRP-RC structures

This paper presents a parametric analysis of the ACI440 (2015) and AASHTO (2009) algorithms governing the flexural design of a one-way concrete member internally reinforced with glass fiber-reinforced polymer (GFRP) bars. The influence of specific design parameters on the required amount of reinforcement is investigated. The aim is to identify variables and requirements governing the design of a large-section GFRP reinforced concrete (RC) member. The member considered for this case-specific analysis is the reinforced concrete pile cap of the Halls River Bridge (Homosassa, FL), which is deemed representative of large-section GFRP-RC members operating as bent caps in short-span bridges. The influence of four critical parameters on the required amount of reinforcement is assessed. Salient analysis and design implications are discussed with respect to creep and fatigue rupture stress limits, minimum amount of flexural reinforcement, and applicable strength reduction factors. The outcomes of the parametric analysis highlight an untapped potential to reduce the required amount of reinforcement, and prioritize research areas to advance the development of rational design algorithms. Cyclic fatigue and creep rupture are identified as governing mechanisms

Unexpected episodes of cyanosis in late preterm and term neonates prompted admission to a neonatal care unit

Abstract Background We studied late preterm and term infants who were admitted to our neonatal care unit in a tertiary hospital for unexpected episodes of cyanosis that occurred during rooming-in for evaluation of their frequency, most frequent associated diseases, and documentation of the diagnostic clinical approach. Methods We carried out a retrospective study of infants with a gestational age ≥35 weeks who were admitted from the nursery with the diagnosis of cyanosis from January 2009 to December 2016. Exclusion criteria were the occurrence of acrocyanosis and the diagnosis of sudden unexpected postnatal collapse (SUPC). Results We studied 49 infants with a mean gestational age of 38 ± 2 weeks. The frequency of admission for cyanosis was 1.8/1000 live births and was similar (p = 0.167) in late preterm and term infants. The majority of episodes occurred during the first 24 h of life (57%). Only 16 infants (33%) were discharged with a diagnosis, that was mostly (n = 5;10%) gastro-esophageal reflux. Conclusions Unexpected episodes of cyanosis caused admission of 1.8/1000 live births to the neonatal care unit without differences between late preterm and term infants. These episodes occurred mainly during the first day of life and infants were mostly discharged without a known diagnosis

Copper(II) Complexes of Cyclams Containing Nitrophenyl Substituents: Push–Pull Behavior and Scorpionate Coordination of the Nitro Group

The three nitrophenyl–cyclam derivatives (nitrocyclams): 1-(4-nitrophenyl)-1,4,8,11-tetraazacyclotetradecane (2), 1-(2-nitrophenyl)-1,4,8,11-tetraazacyclotetradecane (3), and 1-(2,4-dinitrophenyl)-1,4,8,11-tetraazacyclotetradecane (4), in an MeCN solution, specifically incorporate the CuII ion according to an irreversible process signaled by disappearance of the yellow color for a concentration c < 1 × 10–4 M and by a yellow-to-red color change for c ≥ 1 × 10–3, and must be considered efficient and specific dosimeters of copper(II) salts. When present in the ortho position of the nitrophenyl substituent, the −NO2 group coordinates the CuII according to a scorpionate mode, while the metallocyclam system exhibits a trans-I configuration. In an MeCN solution the red trans-I-[CuII(3)]2+ and trans-I-[CuII(4)]2+ scorpionate complexes slowly convert into the violet trans-III scorpionate complexes. Kinetic aspects of the trans-I-to-trans-III configurational rearrangement were investigated in detail for the [CuII(4)]2+ system. In particular, the conversion is spectacularly accelerated by catalytic amounts of Cl–, NCO–, and F–. While for Cl– and NCO– the effect can be associated with the capability of the anion to stabilize through coordination a possible dissociative intermediate, the amazingly powerful effect of F– must be related to the preliminary deprotonation of one N–H fragment of the macrocycle, driven by the formation of the HF2– ion. Most of the metal complex species studied in solution were isolated in a crystalline form, and their molecular structures were elucidated through X-ray diffraction studies. This study documents the first examples of effective metal coordination by the nitro groupThe financial support of the Italian Ministry of University and Research (PRIN−InfoChem) is gratefully acknowledgedS