Search results for " confinement."
showing 10 items of 92 documents
Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating
2017
We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed ‘three-ion’ scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen–deuterium mixtures.…
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…
Efficiency of Stress-Strain Models of Confined Concrete With and Without Steel Jacketing to Reproduce Experimental Results
2016
The improvement and the capacity assessment of existing buildings has become the main topic of the last years so that different studies can be found devoted to damaged structures or structures not having a capacity compatible with the safety levels of the actual codes. Reinforced concrete framed structure buildings represent a conspicuous rate of the existing constructions so many efforts are addressed to them. Referring to this type of buildings, a good prediction of strength and deformation capacity requests models able to interpret the constitutive law of concrete confined by internal reinforcement or by eventual external reinforcement applied to increase capacity of cross-sections. Cons…
Physicochemical investigation of cobalt?iron cyanide nanoparticles synthesized by a novel solid?solid reaction in confined space
2004
Cobalt–iron cyanide (Cox[Fe(CN)6]) nanoparticles have been synthesized by a novel solid–solid reaction in the confined space of dry sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reversed micelles dispersed in n-heptane. The reaction has been carried out by mixing two dry AOT/n-heptane solutions containing CoCl2 and K4Fe(CN)6 or K3Fe(CN)6 nanoparticles in the micellar core, respectively. By UV-Vis spectroscopy it was ascertained that, after the mixing process, the formation of stable nanoparticles is fast and complete. Microcalorimetric measurements of the thermal effect due to the Cox[Fe(CN)6] nanoparticle formation allowed the determination of the stoichiometric ratio (x) and of the molar e…
#Io resto a casa, Nuove forme dell’abitare domestico
2020
Le regolamentazioni igienico-sanitarie hanno influenzato da sempre le teorie urbanistiche, le trasformazioni delle città e le forme dell’abitare. Nell’attesa della soluzione medica, la risposta al Covid19 passa da considerazioni sugli spazi. I cambiamenti più immediati possono avviarsi dalla casa, con un pensiero poietico e in opposizione all’idea che tutto dipenda unicamente dalla tecnologia. Il ragionamento sullo spazio domestico implica la riflessione sui nuovi bisogni (che l’emergenza ha acuito) e sulla ricerca della qualità, con una revisione dei minimi dell’abitare. L’isolamento ha aperto lo sguardo a possibili paesaggi domestici e, se la casa è ancora principio dell’abitare, da essa …
Compressive response of concrete columns under service conditions strengthened by confining devices: from the local to the global behavior.
Il rinforzo di colonne in calcestruzzo armato tramite materiali polimerici fibrorinforzati (FRP) o tramite incamiciature in acciaio conferisce agli elementi strutturali degli edifici esistenti un elevato incremento di capacità portante e deformativa grazie alle proprietà dei materiali che svolgono la funzione di confinamento. Conoscere adeguatamente le proprietà meccaniche degli elementi in calcestruzzo confinato risulta di fondamentale importanza nell’ambito di un progetto di sistemi di rinforzo strutturale. Tuttavia, le normative attualmente vigenti non forniscono prescrizioni su come tenere in considerazione la presenza dei carichi di esercizio sugli elementi strutturali al momento dell’…
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…
QCD Confinement and the Meson Spectrum
2003
From QCD and lattice calculations two specific forms of quark confining potential, a strict linear and a screened linear confinement, come out. Both forms of the potential, implemented by the one gluon exchange interaction, are applied to the description of heavy quarkonia: cc and bb. Applications to light hadrons, mesons and baryons, are also commented.
From capillary condensation to interface localization transitions in colloid-polymer mixtures confined in thin-film geometry.
2008
Monte Carlo simulations of the Asakura-Oosawa (AO) model for colloid-polymer mixtures confined between two parallel repulsive structureless walls are presented and analyzed in the light of current theories on capillary condensation and interface localization transitions. Choosing a polymer to colloid size ratio of q=0.8 and studying ultrathin films in the range of D=3 to D=10 colloid diameters thickness, grand canonical Monte Carlo methods are used; phase transitions are analyzed via finite size scaling, as in previous work on bulk systems and under confinement between identical types of walls. Unlike the latter work, inequivalent walls are used here: while the left wall has a hard-core rep…
Localization and interactions of melatonin in dry cholesterol/lecithin mixed reversed micelles used as cell membrane models
2005
The state of melatonin confined in dry cholesterol/lecithin mixed reversed micelles dispersed in CCl4 was investigated using 1H-NMR and FT-IR spectroscopies as a function of the melatonin to lecithin molar ratio (R(MLT)) and of the cholesterol to lecithin molar ratio (R(CHL)). An analysis of experimental results leads to the hypothesis that, independent of R(MLT) and as a consequence of anisotropic melatonin/lecithin, melatonin/cholesterol and cholesterol/lecithin interactions, melatonin is totally solubilized in reversed micelles. Melatonin is mainly located in and oriented in the nanodomain constituted by the hydrophilic groups of cholesterol and lecithin. A competition of melatonin and c…