Ultrafast Molecular Transport on Carbon Surfaces: The Diffusion of Ammonia on Graphite

We present a combined experimental and theoretical study of the self-diffusion of ammonia on exfoliated graphite. Using neutron time-of-flight spectroscopy we are able to resolve the ultrafast diffusion process of adsorbed ammonia, NH$_3$, on graphite. Together with van der Waals corrected density functional theory calculations we show that the diffusion of NH$_3$ follows a hopping motion on a weakly corrugated potential energy surface with an activation energy of about 4 meV which is particularly low for this type of diffusive motion. The hopping motion includes further a significant number of long jumps and the diffusion constant of ammonia adsorbed on graphite is determined with D=3.9 \cdot 10^{-8}~\mbox{m}^2 /\mbox{s} at 94 K

Pyroclastic lumps: quick diapiric structures off the Naples Bay, Italy. European Geophysical Society (EGS), 25th General Assembly, Millenium Conference on Earth, Planetary & Solar Systems. Nice (France) 25-29 Aprii 2000.

Sacchi M., D'Argenio B., Morra V., Petrazzuoli S., Àiello G., Budillon F., Samacchiaro G. and Tonielli R., 2000. Pyroclastic lumps: quick diapiric structures off the Naples Bay, Italy. European Geophysical Society (EGS), 25th General Assembly, Millenium Conference on Earth, Planetary & Solar Systems. Nice (France) 25-29 Aprii 2000

Risultati preliminari della campagna oceanografica CAFE_07 – Leg 3 nei Golfi di Napoli e Pozzuoli, Mar Tirreno Orientale

Vengono presentati i risultati preliminari della campagna oceanografica CAFE_07 - Leg 3, svoltasi nei Golfi di Napoli e Pozzuoli, nel Gennaio 2008, a bordo della Nave Oceanografica (N/O) URANIA del CNR. Lo scopo della campagna è stato l’acquisizione di profili sismici multicanale di elevata risoluzione dedicati allo studio stratigrafico-strutturale degli apparati vulcanici affioranti e sepolti nell’offshore Napoletano, ed il rilievo batimetrico di dettaglio dell’area sommersa. I dati raccolti sono consistiti in circa 800 km di profili sismici a riflessione multicanale di alta risoluzione, con acquisizione sismica simultanea da due sorgenti GI-gun operanti con potenza e frequenze differenti,mediante due cavi idrofonici. Durante la navigazione sono stati anche acquisiti profili sismici a riflessione monocanale di altissima risoluzione (sub-bottom CHIRP) e dati batimetrici mediante ecoscandaglio multifascio (multibeam). Il grid di acquisizione sismica multicanale è consistito in alcuni profili lunghi attraverso il Golfo di Napoli e da una fitta griglia di profili più corti, con interasse di circa 150 m, allo scopo di ottenere una copertura sismica quasi 3-D del Golfo di Pozzuoli. Questo set di dati costituisce una parte delle indagini di dettaglio richieste per la stesura di una proposta di perforazione del settore sommerso dei Campi Flegrei da sottomettere all’Integrated Ocean Drilling Program (IODP) ed è di supporto alla realizzazione di un progetto di perforazione profonda dei Campi Flegrei presentato all’International Continental Drilling Program (ICDP). We present the preliminary results of the oceanographic cruise CAFE_07 – Leg 3, conducted in the Napoli and Pozzuoli Bays in January 2008, on board of the Research Vessel (R/V) URANIA of the CNR. The aim of the cruise was the acquisition of high resolution multi-channel seismic profiles to understand the stratigraphic-structural setting of the Pozzuoli Bay area, with specific reference to the major offshore volcanic features, as well as the acquisition of bathymetric data on the seafloor morphology of the Bay. About 800 km of seismic profiles were acquired simultaneously by two acquisition systems, each characterized by different seismic source and streamer configuration, operating at different frequency ranges. Moreover shallow high resolution seismic reflection profiles (sub-bottom CHIRP) and multibeam echo-sounder bathymetry data have been recorded. The seismic grid consisted in a number of assistant profiles acquired over the Bay of Naples, along with a dense network of profiles with average distance of about 150 m between navigation routes, in order to obtain a quasi 3-D seismic coverage of the Pozzuoli Bay. This data set represents a part of the requirements for on-site detailed investigations (“site survey”) that are necessary for the development of an Integrated Ocean Drilling Program (IODP) proposal dedicated to the offshore drilling of the Campi Flegrei and is a relevant complement in the site survey of an ongoing project that has been submitted to the International Continental Drilling Program (ICDP)

Individual quality of life description : definition and computation of wellness indexes

LAUREA MAGISTRALELa definizione di benessere individuale è uno dei problemi più discussi nell'ultimo decennio tra i ricercatori. Gli strumenti per valutare lo stato di salute e le condizioni di vita sono stati descritti in letteratura e la maggior parte dei modelli proposti sono costruiti sulla convinzione che il benessere sia un costrutto multidimensionale e che i suoi elementi siano correlati alla salute fisica e mentale dell'individuo. La maggior parte dei ricercatori concorda sul fatto che le interazioni tra l'ambiente sociale e l'individuo hanno un forte contributo al benessere dell'uomo. Con l'avanzamento della tecnologia, l'uso di sensori intelligenti nei nostri ambienti quotidiani sta diventando sempre più comune. L'enorme quantità di dati raccolti dalle smart homes ha permesso la creazione di molte applicazioni che ci aiutano nelle nostre attività quotidiane. Alcuni di questi sistemi intelligenti utilizzano i dati raccolti per monitorare le persone che vivono nelle loro smart homes rilevando i loro bisogni e i loro problemi e intervenendo in situazioni di pericolo. Il nostro lavoro nasce da una ricerca della definizione del benessere e un'analisi degli elementi comuni tra le diverse interpretazioni e implementazioni dei modelli di benessere presenti in letteratura. La nostra revisione dei modelli e delle misurazioni del benessere ha portato alla scoperta di sei dimensioni comuni del benessere presenti nella maggior parte degli studi presi in considerazione. Il punto di partenza del nostro lavoro è il sistema di localizzazione precedentemente progettato e implementato nella struttura sanitaria ``Il Paese Ritrovato" di Monza. Noi proponiamo l'implementazione di un sistema per valutare il benessere individuale attraverso l'utilizzo di un gruppo di indici di benessere che vengono automaticamente calcolati dai dati raccolti dal sistema di localizzazione. Insieme agli indici, proponiamo l'implementazione di una misurazione del benessere che è descritta in letteratura: il questionario Perceived Wellness Survey. Inoltre, il nostro lavoro propone l'implementazione di un sistema automatico per il calcolo delle variazioni degli indici che abbiamo definito e la generazione di notifiche per il personale medico della struttura, che potrebbe offrire metodi rapidi e affidabili per scoprire problemi di salute per i pazienti della struttura sanitaria.The definition of individual wellness is one of the most discussed problems among researchers in the last decade. Instruments to evaluate the status of health and life conditions have been described in the literature and most of the proposed models are built on the belief that wellness is a multidimensional construct and its elements are related to the physical and mental health of the individual. Most researchers agree that the interactions between the social environment and the individual have a strong contribution to the human well-being. With the technology advancement, the use of smart sensors in our everyday environments is becoming more and more common. The huge quantity of data gathered by the smart homes allowed the creation of many applications that aid us in our daily tasks. Some of these smart systems use the gathered data to monitor the people living in their smart homes detecting their needs and problems and intervening in alarming situations. Our work originated with a research of wellness definition and an analysis of the common elements among the different interpretations and implementations of wellness models present in the literature. Our review of the models and measurements of wellness lead to the discovery of six common dimensions of wellness present among most of the studies taken into consideration. The starting point of our work is the indoor localization system previously designed and implemented in the ``Il Paese Ritrovato" healthcare facility structure located in Monza. We propose the implementation of a system to assess the individual wellness through the use of a set of wellness indexes that are automatically computed from the data gathered by the localization system. Together with the indexes, we propose the implementation of one measurement of wellness that is described in the literature: the Perceived Wellness Survey. Furthermore, our work proposes the implementation of an automatic system for the computation of the variations of the defined indexes and the generation of notifications for the medical staff of the structure that could offer fast and reliable methods to discover health-related problems for the patients of the healthcare facility

Weak intermolecular interactions in an ionically bound molecular adsorbate: cyclopentadienyl=Cu(111)

The dissociative adsorption of cyclopentadiene (C5H6) on Cu(111) yields a cyclopentadienyl (Cp) species with strongly anionic characteristics. The Cp potential energy surface and frictional coupling to the substrate are determined from measurements of dynamics of the molecule together with density functional calculations. The molecule is shown to occupy degenerate threefold adsorption sites and molecular motion is characterized by a low diffusional energy barrier of 40 +/- 3 meV with strong frictional dissipation. Repulsive dipole-dipole interactions are not detected despite charge transfer from substrate to adsorbate

Supramolecular self-assembled network formation containing N···Br halogen bonds in physisorbed overlayers.

The formation of a halogen bonded self-assembled co-crystal physisorbed monolayer containing N···Br interactions is reported for the first time. The co-crystal monolayer is identified experimentally by synchrotron X-ray diffraction and the structure determined. Density functional theory (DFT) calculations are also employed to assess the magnitudes of the different interactions in the layer. Significantly, compared to other halogen bonds in physisorbed monolayers we have reported recently, the N···Br bond here is found to be non-linear. It is proposed that the increasing importance of the lateral hydrogen bond interactions, relative to the halogen bond strength, leads to the bending of the halogen bonds.We acknowledge financial support for AB from EPSRC DTA award from the Department of Chemistry, University of Cambridge. We acknowledge Diamond Light Source for time on beamline I11 under proposals EE6511 and EE7761.This is the final version of the article. It first appeared from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C4CP03379

“Pop-on and pop-off” surface chemistry of alanine on Ni{111} under elevated hydrogen pressures

The co-adsorption of hydrogen with a simple chiral modifier, alanine, on Ni{111} was studied using Density Functional Theory in combination with ambient-pressure X-ray photoelectron spectros opy and X-ray absorption spectroscopy at temperatures of 300 K and above, which are representative of chiral hydrogenation reactions. Depending on the hydrogen pressure, the surface enables protons to ''pop on and off'' the modifier molecules, thus significantly altering the adsorption geometry and chemical nature of alanine from anionic tridentate in ultra-high vacuum to predominantly zwitterionic bidentate at hydrogen pressures above 0.1 Torr. This hydrogen-stabilised modifier geometry allows alternative mechanisms for proton transfer and the creation of enatioselective reaction environments

The effect of molecular vibrations and surface structure on the chemisorption of methane on platinum

In this thesis, I report state-resolved measurements of the chemisorption probability of CH4 on Pt(111) and Pt(110)-(1×2) for several rovibrationally excited states (2ν3, ν1+ν4, and 2ν2+ν4) in addition to the ground state. Measurements of the state resolved reactivity as function of the incident translational energy lead to state-resolved reactivity curves for each of the states under study. The relative efficacy of activating the dissociation reaction is obtained for each excited state by comparing the increase in reactivity observed upon excitation of a particular state to the effect of increasing the translational energy of CH4 in the ground state. The results provide clear evidence for mode specific reactivity with the highest efficacy for the stretch-bend combination (ν1+ν4), followed by the stretch overtone (2ν3) and the bend overtone state (2ν2+ν4). The results demonstrate that vibrational activation of CH4/Pt chemisorption process does not simply scale with the total internal energy of the incident CH4 molecule, which is a central assumption of the PC-MURT statistical model for dissociative chemisorption reactions developed by the group of Harrison [Ukraintsev et al., Chem. Phys., 1994. 101(2): p. 1564]. On the contrary, the qualitative predictions of the vibrationally adiabatic model proposed by Halonen et al. [J. Chem. Phys., 2001. 115(12): p. 5611] are in good agreement with our results. The higher efficacy of the ν1+ν4 state can also be rationalized by observing that, at the transition state, the breaking C-H bond is both stretched and bent from its equilibrium geometry, therefore I suggest that this state might have a significant projection on the reaction coordinate [Psofogiannakis et al., J. Phys. Chem. B, 2006. 110 : p. 24593 ; Anghel et al., Phys. Rev. B, 2005. 71 : p. 4]. Comparison between the state-resolved reactivity for CH4(2ν3) on Pt(111) and Ni(111) is used to obtain information about differences in barrier height and transition state location for the dissociation on the two different metals [Bisson et al., J. Phys. Chem., 2007. 111: p. 12679]. Finally, for the more corrugated Pt(110)-(1×2) surface, I determined the state-resolved sticking coefficients for different polar and azimuthal angles of incidence. Comparison between the reaction probability for incidence parallel and perpendicular to the missing rows of this surface shows shadowing effects that are consistent with predominant reactivity of the top layer Pt atoms

Colour variation of the Maltese wall lizards (Podarcis filfolensis) at population and individual levels in the Linosa island

AbstractThe research on animal colouration has always been of great interest for biologists but since the last decades it has grown exponentially thanks to multidisciplinary approaches. Animals have found several ways to deal with the camouflage/communication trade-off in colouration, leading to the evolution of alternative patterns of variation of colourations at different levels including signal partitioning and spatial resolution of colouration. In this paper we analyse the variability of dorsal and ventral colouration in males and females of Maltese wall lizards in three populations on Linosa. We collected high-resolution digital images of dorsal, ventral and throat colouration from 61 lizards (32 males and 29 females). We showed that the colouration differs among sexes and body regions within the same individual. Colourations are also variable among individuals within population, as well as among different populations across the Island. Finally, we detected a lizard's colouration shifts with increasing body size. Those result supports the hypothesis that colouration in this species evolved under the competing pressures of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators. Graphic abstrac