The Environmental Attitudes and Behaviours of European Golf Tourists

Environmental attitudes and behaviours have received relatively little attention in golf tourism, compared to other tourism research areas. Golf tourism provides products and services based on nature, and they should focus on the environment. Golf has become increasingly important in the development of European tourism within the last decade. Moreover, golf is one of the primary motivations for European tourists in the sports tourism sector. This study is based on a sample of 431 golf tourists, from different nationalities, who visit Andalusia, Spain. This research examines the relationship between environmental attitudes and behavioural intentions for three subsamples of European nationalities: British, German, and Spanish. This relationship was corroborated in the three subsamples. However, the national citizenship of European golf tourists was not a moderator effect on the relationship between environmental attitudes and behavioural intentions

Molecular dynamics simulations of the meltinglike transition in Li13Na42 and Na13Cs42 clusters

Producción CientíficaEquilibrium geometries and the meltinglike transition of Na13Cs42 and Li13Na42 are studied by means of orbital-free density-functional-theory molecular dynamics simulations. A polyicosahedral structure is found to be energetically favored for Na13Cs42, with a core shell formed by Na atoms and complete segregation of Cs atoms to the cluster surface. Li13Na42 adopts an amorphouslike structure, albeit with significant local polyicosahedral order, with the Na atoms preferentially occupying surface sites but with partial mixing of Li and Na species at the cluster core. Analysis of the thermal properties reveals that premelting effects are more important for heterogeneous than for homogeneous alkali clusters. The nature of these premelting effects is discussed in detail. For Na13Cs42, they involve isomerizations without significant atom diffusion; for Li13Na42, they also include partial melting of the surface formed by Na atoms. The mixing of Li and Na species is significantly enhanced above the melting temperature, while surface segregation of Cs in Na13Cs42 is maintained in the liquid state. From the study of these two clusters, we attemp to extract some general trends about the structural and thermal behaviors of heterogeneous alkali clusters

Characterization of electrical crosstalk in 4T-APS arrays using TCAD simulations

TCAD simulations have been conducted on a CMOS image sensor in order to characterize the electrical component of the crosstalk between pixels through the study of the electric field distribution. The image sensor consists on a linear array of five pinned photodiodes (PPD) with their transmission gates, floating diffusion and reset transistors. The effect of the variations of the thickness of the epitaxial layer has been addressed as well. In fact, the depth of the boundary of the epitaxial layer affects quantum efficiency (QE) so a correlation with crosstalk has been identified.Ministerio de Economía y Competitividad TEC2015-66878-C3-1RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

Small sodium clusters that melt gradually: Melting mechanisms in Na30

Producción CientíficaThe meltinglike transition of Na30 is studied by orbital-free density-functional molecular dynamics simulations. The potential energy surface of Na30 is sampled by simulated annealing and regular quenchings performed along the dynamical trajectories. Both the ground-state structure and low-energy structural excitations are found to exhibit substantial polyicosahedral ordering. The most relevant feature of the potential energy landscape for the melting problem is the existence of many different structural isomers within an energy range of 1 meV/atom, resembling that of a glassy system (yet the structures have a high symmetry). The liquid phase is accessed gradually, with some isomerizations observed at a temperature as low as 30 K, while melting can be considered complete above approximately 200 K. The different dynamical mechanisms that allow the smooth opening of phase space available to the system as a function of temperature are identified and discussed. They can be classified in two different categories: (a) those that allow the exploration of isomers similar to the ground state, involving mainly surface isomerizations and surface melting, and leaving the structure of the cluster core unchanged; and (b) those associated with a more substantial structural change, more similar to the usual solid-solid phase transition in bulk phases; the structure of the cluster core changes only in this second type of transition. Mechanism (a) results in surface melting of the corresponding isomer upon heating; at that stage, mechanism (b) acts to transfer some excess energy from the surface to the core region, so that the surface melting is transiently avoided. Even in the fully developed liquid state, there are important differences from the bulk liquid due to the presence of the surface

Structural and thermal behavior of compact core-shell nanoparticles: Core instabilities and dynamic contributions to surface thermal stability

Producción CientíficaAn orbital-free density-functional-theory molecular dynamics technique is applied to investigate the minimum-energy structure and meltinglike transition of Cs55, Li13Na32Cs42, and Li55Cs42 nanoparticles. Icosahedral packing is found to be optimal for homogeneous Cs55, as expected. Heterogeneous particles show a complete segregation of Cs atoms to the cluster surface, and form perfect core-shell structures, that is, structures where each atomic species occupies and completes a different concentric atomic shell. For Li13Na32Cs42, the size mismatch between atomic species forming different shells leads to polyicosahedral packing. For Li55Cs42, however, the size mismatch is huge and perfect polyicosahedral ordering is frustrated, resulting in more complex structural behavior. The three clusters investigated share the same surface shell, formed by 42 Cs atoms, and comparison of their melting behaviors helps to rationalize the increased thermal stability of the cluster surface upon alloying. Cs55 melts homogeneously at approximately 85 K. Both Li13Na32Cs42 and Li55Cs42 show a substantial thermal stability, compared to Cs55 and other alloy compositions where a perfect core-shell structure does not appear. We demonstrate that an important contribution to this increased thermal stability in the nanoalloys comes from the large difference in the atomic masses of the constituent particles, which results in a poor coupling of atomic vibrations along the radial direction. We also give arguments to show that the meltinglike transition in these clusters is triggered by the thermal instability of interior rather than surface atoms. Segregation of Cs atoms to the cluster surface is fully maintained in the liquid state, so that core and surface shells form two inmiscible liquid layers

Anomalous Size Dependence in the Melting Temperatures of Free Sodium Clusters: An Explanation for the Calorimetry Experiments

Producción CientíficaThe meltinglike transition in unsupported NaN clusters (N=55, 92, 147, 181, 189, 215, 249, 271, 281 and 299) is studied by first-principles isokinetic molecular dynamics simulations. The irregular size dependence of the melting temperatures Tm observed in the calorimetry experiments of Schmidt et al. [ Nature (London) 393 238 (1998)] is quantitatively reproduced. We demonstrate that structural effects alone can explain all broad features of experimental observations. Specifically, maxima in Tm(N) correlate with high surface stability and with structural features such as a high compactness degree