Search results for "GASES"

Structure, Spectroscopy, and Spectral Tuning of the Gas-Phase Retinal Chromophore: The β-Ionone "Handle" and Alkyl Group Effect

2005

The low-lying singlet states (i.e. S0, S1, and S2) of the chromophore of rhodopsin, the protonated Schiff base of 11-cis-retinal (PSB11), and of its all-trans photoproduct have been studied in isolated conditions by using ab initio multiconfigurational second-order perturbation theory. The computed spectroscopic features include the vertical excitation, the band origin, and the fluorescence maximum of both isomers. On the basis of the S0-->S1 vertical excitation, the gas-phase absorption maximum of PSB11 is predicted to be 545 nm (2.28 eV). Thus, the predicted absorption maximum appears to be closer to that of the rhodopsin pigment (2.48 eV) and considerably red-shifted with respect to that…

Micelles, Rods, Liposomes, and Other Supramolecular Surfactant Aggregates: Computational Approaches

2017

Surfactants are an interesting class of compounds characterized by the segregation of polar and apolar domains in the same molecule. This peculiarity makes possible a whole series of microscopic and macroscopic effects. Among their features, their ability to segregate particles (fluids or entire domains) and to reduce the surface/interfacial tension is the utmost important. The interest in the chemistry of surfactants never weakened; instead, waves of increasing interest have occurred every time a new field of application of these molecules has been discovered. All these special characteristics depend largely on the ability of surfactants to self-assemble and constitute supramolecular struc…

Superfluid density and quasi-long-range order in the one-dimensional disordered Bose–Hubbard model

2015

We study the equilibrium properties of the one-dimensional disordered Bose-Hubbard model by means of a gauge-adaptive tree tensor network variational method suitable for systems with periodic boundary conditions. We compute the superfluid stiffness and superfluid correlations close to the superfluid to glass transition line, obtaining accurate locations of the critical points. By studying the statistics of the exponent of the power-law decay of the correlation, we determine the boundary between the superfluid region and the Bose glass phase in the regime of strong disorder and in the weakly interacting region, not explored numerically before. In the former case our simulations are in agreem…

EVIDENCES OF ENRICHED MANTLE (EM-2) SOURCE CONTRIBUTION TO ETNEAN MAGMAS: A COMPREHENSIVE STUDY ON FLUID AND MELT INCLUSIONS OF 2001-2006 ERUPTIONS

2009

Determinazione in continuo di CO2, CH4 e H2Ov in ambiente atmosferico attraverso tecnica ad assorbimento laser (UGGA)

2015

Molti dei composti chimici presenti nell’atmosfera terrestre prendono il nome di “gas serra”. Queste specie gassose consentono alla radiazione solare di entrare liberamente nell’atmosfera e di trattenere parte della radiazione solare riflessa dalla superficie terrestre come energia termica. Nel corso del tempo si instaura un complesso equilibrio termico tra la quantità di energia inviata dal sole e quella irradiata dalla superficie. L’alterazione di questo equilibrio, con l’aumento di uno o più gas serra in atmosfera, porta a degli squilibri termici e un conseguente innalzamento delle temperature. Questo fenomeno è definito come “effetto serra”. I principali gas serra in natura che prendono…

Greenhouse gas emissions from integrated solid waste management: a new mathematical model

2016

Municipal solid waste management significantly contributes to the emission in the atmosphere of greenhouse gases (e.g. CO2, CH4, N2O) and therefore the management process from collection to treatment and disposal has to be optimized in order to reduce these emissions. Many literature models developed for the evaluation of greenhouses gases emissions from the waste management system are based on the analysis of the life cycle. These models are not optimized for evaluation of emissions. The aim of this study is to overcome these limitations by proposing a mathematical model to estimate greenhouse gas emissions resulting from the integrated waste management. The model is aimed to be a verifica…

Molecular and isotopic composition of free hydrocarbon gases from Sicily, Italy

2004

Chemical and isotopic data have been used as geochemical tracers for a genetic characterization of hydrocarbon gases from a total of eleven manifestations located in Eastern and Central-Southern Sicily (Italy). The molecular analysis shows that almost all the samples are enriched in methane (up to 93.2% Vol.), with the exception of four gas samples collected around Mt. Etna showing high mantle-derived CO2 content. Methane isotope signatures suggest that these are thermogenic gases or a mixture between thermogenic gases and microbial gases. Although samples from some mud volcanoes in Southern Sicily (Macalube di Aragona) show isotope signatures consistent with a mixing model between thermoge…

A TWO-COMPONENT MANTLE EXTENDING FROM MT ETNA TO HYBLEAN PLATEAU (EASTERN SICILY) AS INFERRED BY AN INTEGRATED APPROACH WITH NOBLE GASES, TRACE ELEME…

2012

Optofluidic taming of a colloidal dimer with a silicon nanocavity

2014

International audience; We report here the optical trapping of a heterogeneous colloidal dimer above a photonic crystal nanocavity used as an on-chip optical tweezer. The trapped dimer consists of a cluster of two dielectric microbeads of different sizes linked by van der Waals forces. The smallest bead, 1 μm in diameter, is observed to be preferentially trapped by the nanotweezer, leaving the second bead untrapped. The rotational nature of the trapped dimer Brownian motion is first evidenced. Then, in the presence of a fluid flow, control of its orientation and rotation is achieved. The whole system is found to show high rotational degrees of freedom, thereby acting as an effective flow-se…

A description based on languages of the final non-deterministic automaton

2014

The study of the behaviour of non-deterministic automata has traditionally focused on the languages which can be associated to the different states. Under this interpretation, the different branches that can be taken at every step are ignored. However, we can also take into account the different decisions which can be made at every state, that is, the branches that can be taken, and these decisions might change the possible future behaviour. In this case, the behaviour of the automata can be described with the help of the concept of bisimilarity. This is the kind of description that is usually obtained when the automata are regarded as labelled transition systems or coalgebras. Contrarily t…