Search results for " confinement."
showing 10 items of 92 documents
Effect of FRP Wraps on the Compressive Behaviour of Slender Masonry Columns
2017
In the last decade, Fibre Reinforced Polymer (FRP) wrapping technique has become a common method to retrofit masonry piers or columns with poor structural performances. The passive confinement effect induced by the external wrap allows increasing the compressive strength and ductility of the member. Several studies highlighted as the efficacy of this technique is affected by several key parameters, including the shape of the transverse cross section, stress intensification at the strength corner of sharp sections, amount and mechanical properties of adopted composite. Despite this technique has been widely studied from both theoretical and experimental point of view, most of studies focused…
Concrete columns confined with fibre reinforced cementitious mortars: Experimentation and modelling
2014
Abstract The structural behaviour of concrete columns strengthened with a system made up of fibre nets embedded in an inorganic stabilized cementitious matrix under an uniaxial load was investigated. Medium size specimens with circular and square cross-section were cast and subjected to monotonic uniaxial compression, to investigate the efficiency of a p-Phenylene BenzobisOxazole (PBO) Fibre Reinforced Cementitious Mortar (FRCM) system in increasing both strength and ductility. The experimental results show that the confinement system adopted produced a noticeable increment in strength and ductility, though the low mechanical ratios of fibre considered were not always able to ensure hardeni…
EFFICACY OF PBO-FRCM STRENGTHENING OF RC COLUMNS IN MRFS
2019
Innovative materials and techniques are widespread used for the strengthening and rehabilita-tion of existing structures. Recent researches have been developed on new fiber reinforced composites in which epoxy resin is replaced by inorganic cementitious material. These kind of cement-based composite material is known as Fiber Reinforced Cementitious Matrices (FRCM) recently used also in combination with synthetic polymeric fibers named PBO. The efficiency of this new confining system has been demonstrated by a large number of com-pression tests on concrete specimens while there are only few experimental researches on the behaviour of large scale specimens under external action able to simul…
Core (XUV/VUV) and boundary (UV/vis/IR) plasma spectroscopy in fusion devices
2021
This contribution describes the basic applications of passive optical emission spectroscopy in the visible and far-UV region of electromagnetic radiation to diagnostics of the magnetic confinement fusion plasma. To simplify and condense the broad topic it presents the most common ways of analyzing the spectra of atoms, ions and molecules in fusion plasma and disseminating results of those analysis to the non-spectroscopists. It provides the reasons for choosing some particular regions, elements and charge states to determine the impurity content and plasma-surface interactions in MCF (Magnetic Confinement Fusion) reactor. Examples used in the contribution are predominantly from measurements…
Confinement, the gluon propagator and the interquark potential for heavy mesons
2012
The interquark static potential for heavy mesons described by a massive one-gluon exchange interaction obtained from the propagator of the truncated Dyson-Schwinger equations does not reproduced the expected Cornell potential. I show that no formulation based on a finite propagator will lead to confinement of quenched QCD. I propose a mechanism based on a singular nonperturbative coupling constant which has the virtue of giving rise to a finite gluon propagator and (almost) linear confinement. The mechanism can be slightly modified to produce the screened potentials of unquenched QCD.
Efficiency investigation of a negative hydrogen ion beam production with the use of the gasdynamic ECR plasma source
2020
Abstract Negative hydrogen ion sources are of great demand in modern physics as injectors into accelerators and drivers for neutral beam injectors for fusion devices. It has been shown earlier that the use of the gasdynamic ECR discharge provides the opportunity to extract up to 80 mA/cm2 of negative ion current density. We studied experimentally the volumetric negative hydrogen ion production and vacuum ultraviolet emission in a gasdynamic ECR discharge. The high-density plasma was sustained by the pulsed 37 GHz / 100 kW gyrotron radiation in a magnetic configuration consisting of two consecutive simple mirror traps. The future prospects of the volumetric H− source based on the gasdynamic …
Printing Biology for Advanced Synthetic Biosystem
2019
Printing technologies represent a powerful tool for the direct micro- and nano- fabrication of biomolecular structures at the interface between life and materials sciences (Arrabito et al., 2012). Their continuous development over the last years has permitted the onset of man-made biosystems with customizable dimensions (from the micron-scale down to the nanometer scale), composition (organic molecules, DNA, proteins, phospholipids), and relevant functions (molecular interactions, drug screening, cellular biointerfaces, cell-like compartments). In this work, we show the possibility to leverage the fabrication of a wide class of solid-supported or liquid-liquid based synthetic compartments b…
Major results from the first plasma campaign of the Wendelstein 7-X stellarator
2017
After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for t…
The assessment of lifestyle changes during the COVID-19 pandemic using a multidimensional scale
2020
Introduction Healthy lifestyles are relevant to several diseases and to maintain individuals’ mental health. Exposure to epidemics and confinement have been consistently associated with psychological consequences, but changes on lifestyle behaviours remain under-researched. Materials and Methods An online survey was conducted among the general population living in Spain during the COVID-19 home-isolation. In addition to demographic and clinical data, participants self-reported changes in seven lifestyle domains. The Short Multidimensional Inventory Lifestyle Evaluation was developed specifically to evaluate changes during the confinement (SMILE-C). Results A total of 1254 individuals comple…
The differences of Slovenian and Italian daily practices experienced in the first wave of covid-19 pandemic
2022
Abstract Background The COVID-19 pandemic situation with the lockdown of public life caused serious changes in people's everyday practices. The study evaluates the differences between Slovenia and Italy in health-related everyday practices induced by the restrictive measures during first wave of the COVID-19 pandemic. Methods The cross-sectional cohort study examined changes through an online survey conducted in nine European countries from April 15–28, 2020. The survey included questions from a simple activity inventory questionnaire (SIMPAQ), the European Health Interview Survey, and some other questions. To compare difference in changes between European countries we examined Italy with s…