Search results for "Confinement"
showing 3 items of 213 documents
Physicochemical investigation of surfactant-coated gold nanoparticles synthesized in the confined space of dry reversed micelles
2006
Abstract Gold nanoparticle/surfactant composites have been synthesized by a novel reduction reaction in the confined space of dry sodium bis(2- ethylhexyl)sulfosuccinate (AOT) or lecithin reversed micelles dispersed in n-heptane and cyclohexane, respectively. The reaction was carried out by adding an opportune amount of anhydrous hydrazine/tetrahydrofuran solution to a suspension of HAuCl4-containing dry reversed micelles dispersed in organic solvent. UV–vis investigation ascertained the formation of stable metal gold nanoparticles and the analysis of FT-IR spectra highlighted the formation of an oriented surfactant monolayer at the nanoparticle surface. Simple evaporation under vacuum of t…
Child Well-Being in Times of Confinement: The Impact of Dialogic Literary Gatherings Transferred to Homes
2020
The COVID-19 pandemic has created an unexpected situation that has forced people to find educational alternatives to support learning and ensure child well-being. The need for practices that 'open doors' at home as a way to promote a quality education and to foster an environment of supportive relationships and a sense of community, has led to the in-depth analysis of successful educational actions, particularly the Dialogic Literary Gatherings (DLGs). The aim of this article is to show how the transference of DLGs to the home environment has had an impact on child subjective well-being in times of confinement, promoting a safe and supportive environment for learning, interacting, coexistin…
Laser fluence, repetition rate and pulse duration effects on paint ablation
2006
Abstract The efficiency (mm3/(J pulse)) of laser ablation of paint was investigated with nanosecond pulsed Nd:YAG lasers (λ = 532 nm) as a function of the following laser beam parameters: pulse repetition rate (1–10,000 Hz), laser fluence (0.1–5 J/cm2) and pulse duration (5 ns and 100 ns). In our study, the best ablation efficiency (η ≅ 0.3 mm3/J) was obtained with the highest repetition rate (10 kHz) at the fluence F = 1.5 J/cm2. This ablation efficiency can be associated with heat accumulation at high repetition rate, which leads to the ablation threshold decrease. Despite the low thermal diffusivity and the low optical absorption of the paint (thermal confinement regime), the ablation th…