Search results for " Confinement"

Plasma diagnostic tools for ECR ion sources : What can we learn from these experiments for the next generation sources

2019

International audience; The order-of-magnitude performance leaps of ECR ion sources over the past decades result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency, and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves, significant effort has been directed into the development of their plasma diagnostic tools. We review the recent results of Electron Cyclotron Resonance Ion Source (ECRIS) plasma diagnostics highlighting a number of selected examples of plasma density, electron energy distribution, and ion confinement time measurements, obtained mostly with the second-gener…

COVID-19, Gender Housework Division and Municipality Size in Spain

2022

The COVID-19 health crisis brought with it an increase in the workload on family members due to the restriction of services and the suspension of formal and informal care networks. Numerous studies have analyzed how home confinement have affected different gender gaps, including the gender gap related to chores within the home. This research aims to contribute to the existing literature from the perspective of gender geography by introducing the variable municipality size in the analyses. Our research in the case of Spain shows the COVID-19 health crisis to have had a significant impact on gender gaps, albeit to varying degrees. Women, especially those living in small municipalities, experi…

A Theoretical Model to Evaluate the Compressive Behaviour of RС Jacketed Columns

2016

Reinforced concrete (RC) jacketing is becoming increasingly common among the different retrofit techniques for poor RC members, due to its economical and practical advantages. Experimental investigations in the literature have shown that the actual axial capacity of RC jacketed members can be substantially lower than that analytically evaluated by adapting the most common theoretical models for confined concrete. This fact can be explained by taking into account the presence of tensile stresses developing in the concrete, due to a mutual interaction between the inner core and the external jacket. This phenomenon is relevant especially in members where the concrete properties of the jacket a…

RC column externally strengthened with RC jackets

2013

In this paper the behaviour in compression of RC columns externally strengthened with concrete jacketing is analysed and a cross-section analysis of the jacketed member under axial load and bending moment is developed. The focus was to study the effect of confinement of concrete jacket on concrete core and the behaviour of compressed bars with buckling effects. Some other important aspects such as shrinkage, creep, old to new concrete surfaces and bond split effects were not included in the model because: the use of thick non-shrink grout jacket and a well-roughened surface of old-to-new concrete was supposed; long term effects were included though corrective coefficients for monolithic beh…

Observer for a thick layer of solid deuterium-tritium using backlit optical shadowgraphy and interferometry.

2007

Our work is in the context of the French "laser megajoule" project, about fusion by inertial confinement. The project leads to the problem of characterizing the inner surface, of the approximately spherical target, by optical shadowgraphy techniques. Our work is entirely based on the basic idea that optical shadowgraphy produces "caustics" of systems of optical rays, which contain a great deal of 3D information about the surface to be characterized. We develop a method of 3D reconstruction based upon this idea plus a "small perturbations" technique. Although computations are made in the special "spherical" case, the method is in fact general and may be extended to several other situations.

Analisi Sperimentale del Comportamento Ciclico di Elementi in Calcestruzzo a Bassa Resistenza Confinati con FRCM

2013

Vengono riportati i principali risultati di una campagna sperimentale finalizzata alla caratterizzazione della risposta sotto carichi assiali ciclici di colonne di calcestruzzo a bassa resistenza con sezione circolare, quadrata e rettangolare, rinforzate con fibre di carbonio immerse in matrice cementizia (CFRCM). Sono state condotte prove di compressione assiale su 30 campioni di altezza 600 mm, 10 a sezione cilindrica di diametro 300 mm, 10 quadrata di lato 200 mm, e 10 rettangolare di lato 200x400 mm. Le prove sono finalizzate a indagare gli effetti del carico ciclico, della forma della sezione, del raggio di curvatura degli spigoli e del numero di strati di tessuto di rinforzo sul legam…

PBO textile embedded in FRCM for confinement of r.c. columns

2014

Results of experimental tests on two reinforced concrete columns confined with PBO-FRCM jacketing subject to axial load and bending moments are presented, showing the effectiveness of the confinement system. Comparison of test results against theoretical results derived by a fiber model stress the ability of the confinement system to enhance both strength and deformation capacity of the confined concrete

A Handy Stress-Strain Law for FRP Confined Concrete

2006

An experimental study on the compressive behaviour of calcarenite masonry columns wrapped by fiber reinforced mortar wraps

2018

The use of Fiber Reinforced Cementitious Mortar (FRCM) systems for structural retrofitting of masonry structures has become increasingly popular in the last years, due to the capability of this technique in overcoming some of the drawbacks related to the adoption of resin-based composites. In fact, FRCM systems ensure good compatibility between the reinforcing layers and the substrate, achieving also the removability requirement, which is of fundamental importance for historical constructions. Recent research studies focused on the mechanical performance of FRCM materials, by studying its tensile behaviour and bond between the strengthening layer and masonry, pointing out as failure is alwa…

First observation of trapped high-field seeking ultracold neutron spin states

2011

Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement. ISSN:0370-2693 ISSN:0031-9163 ISSN:1873-2445