Metallic slabs: Perturbative treatments based on jellium

We examine first-order perturbative results based on jellium for the surface energy of slabs of simple metals, using various local pseudopotentials (Ashcroft, Heine-Abarenkov and evanescent core). The difference between the pseudopotential and the jellium potential is averaged along the plane parallel to the surface. We compare these perturbative results with those of the stabilized jellium model (a modification of the regular jellium model in which the perturbation appears in the energy functional right from the outset) and with the output of other perturbative and non-perturbative calculations.Comment: 15 pages, 2 figures, to appear in Prog. Surf. Sc

UCity: utopias and dystopias

A part of the Third International Conference for Young Urban Researchers (TICYUrb) held in June 2018, the track UCITY was designed to help participants reflect on the roles of Utopias, Dystopias and Heterotopias in reflecting about and rethinking the city in the present, past and future. Particularly, utopian and dystopian literature have influenced the debate throughout the nineteenth and twentieth centuries, helping to make the city the center of our most fertile imaginaries about the future, social progress and transformation. Cities evolved to symbolize the future of Humanity and thus utopian, dystopian and heterotopian scenarios became alternative reflections of who we wished to become. With the rise of the ubiquitous Smart Cities paradigm, it is extremely important that we collaborate with the Arts and Humanities to imagine and discuss alternative ideas for the future of our cities. From a collective project to an insurgent tool for urban inquiry, the term utopia is explored in the following discussions as a representation of the much needed space for dialogue about what is possible, desirable and valuable.info:eu-repo/semantics/publishedVersio

Liquid Polymorphism and Density Anomaly in a Lattice Gas Model

We present a simple model for an associating liquid in which polymorphism and density anomaly are connected. Our model combines a two dimensional lattice gas with particles interacting through a soft core potential and orientational degrees of freedom represented through thermal \char`\"{}ice variables\char`\"{} . The competition between the directional attractive forces and the soft core potential leads to a phase diagram in which two liquid phases and a density anomaly are present. The coexistence line between the low density liquid and the high density liquid has a positive slope contradicting the surmise that the presence of a density anomaly implies that the high density liquid is more entropic than the low density liquid

Diffusion anomaly and dynamic transitions in the Bell-Lavis water model

In this paper we investigate the dynamic properties of the minimal Bell-Lavis (BL) water model and their relation to the thermodynamic anomalies. The Bell-Lavis model is defined on a triangular lattice in which water molecules are represented by particles with three symmetric bonding arms interacting through van der Waals and hydrogen bonds. We have studied the model diffusivity in different regions of the phase diagram through Monte Carlo simulations. Our results show that the model displays a region of anomalous diffusion which lies inside the region of anomalous density, englobed by the line of temperatures of maximum density (TMD). Further, we have found that the diffusivity undergoes a dynamic transition which may be classified as fragile-to-strong transition at the critical line only at low pressures. At higher densities, no dynamic transition is seen on crossing the critical line. Thus evidence from this study is that relation of dynamic transitions to criticality may be discarded

Dynamic Transitions in a Two Dimensional Associating Lattice Gas Model

Using Monte Carlo simulations we investigate some new aspects of the phase diagram and the behavior of the diffusion coefficient in an associating lattice gas (ALG) model on different regions of the phase diagram. The ALG model combines a two dimensional lattice gas where particles interact through a soft core potential and orientational degrees of freedom. The competition between soft core potential and directional attractive forces results in a high density liquid phase, a low density liquid phase, and a gas phase. Besides anomalies in the behavior of the density with the temperature at constant pressure and of the diffusion coefficient with density at constant temperature are also found. The two liquid phases are separated by a coexistence line that ends in a bicritical point. The low density liquid phase is separated from the gas phase by a coexistence line that ends in tricritical point. The bicritical and tricritical points are linked by a critical $\lambda$-line. The high density liquid phase and the fluid phases are separated by a second $\tau$ critical line. We then investigate how the diffusion coefficient behaves on different regions of the chemical potential-temperature phase diagram. We find that diffusivity undergoes two types of dynamic transitions: a fragile-to-strong trans ition when the critical $\lambda$-line is crossed by decreasing the temperature at a constant chemical potential; and a strong-to-strong transition when the $\tau$-critical line is crossed by decreasing the temperature at a constant chemical potential.Comment: 22 page

New working spaces in Lisbon from a chrono-urbanism planning perspective

In the last two decades, scholars and planning practitioners have been discussing chrono-urbanism approaches trying to respond to urban sprawl and proposing new urban models based on proximity and access to essential goods, services and welfare opportunities for city residents (Guzman et al., 2021). The COVID-19 pandemic brought this theme to the spotlight, mainly through the 15 minute (15’) city concept (Moreno et al., 2021; Pozoukidou and Chatziyiannaki, 2021) as a way to promote more sustainable, livable and healthy cities. Furthermore, the pandemic has significantly impacted how and where people live and work (Florida, Rodríguez-Pose and Storper, 2021), which is expected to extend beyond the present moment. However, the role of New Workspaces (NWS) that proliferate in our cities (e.g., coworking spaces, fab labs, incubators, maker spaces, etc.) and their potential for creating more sustainable and livable neighbourhoods have not been satisfactorily discussed in these approaches. Choosing a working space to work at a 15' distance (on foot or by bike) from home and accessible to a variety of urban functions can have various impacts on our neighbourhoods, as well as changing mobility patterns and improving people's quality of life (e.g., promoting work-life balance and leaving space for healthier lifestyles. The study presented here is part of a broader investigation (see Di Marino et al., 2022). Driven by increased remote work and flexible work arrangements for a wide range of work activities and users, it has favoured the emergence of new types of workspaces. Some of these reflect the specificities of other sectors, such as the tourism and hospitality industry or the new demands of the workforce (e.g. coliving spaces). To discuss the recent chrono-urban approaches applied to urban planning and the growing and increasingly diverse phenomenon of NWS, the city of Lisbon is empirically examined. To this end, the investigation carried out included identifying and mapping the diversity of NWS, a qualitative analysis of Lisbon planning documents and interviews with key informants, as well as a spatial analysis of accessibility, proximity, density and diversity of different urban functions in the 15' around the NWS.info:eu-repo/semantics/publishedVersio

Liquid polymorphism and density anomaly in a three-dimensional associating lattice gas

We investigate the phase diagram of a three-dimensional associating gas $(ALG)$ model. This model combines orientational ice-like interactions and ``van der Waals'' that might be repulsive, representing, in this case, a penalty for distortion of hydrogen bonds. These interactions can be interpreted as two competing distances making the connection between this model and continuous isotropic soft-core potentials. We present Monte Carlo studies of the $ALG$ model showing the presence of two liquid phase, two critical points and A density anomaly

Hydration and anomalous solubility of the Bell-Lavis model as solvent

We address the investigation of the solvation properties of the minimal orientational model for water, originally proposed by Bell and Lavis. The model presents two liquid phases separated by a critical line. The difference between the two phases is the presence of structure in the liquid of lower density, described through orientational order of particles. We have considered the effect of small inert solute on the solvent thermodynamic phases. Solute stabilizes the structure of solvent, by the organization of solvent particles around solute particles, at low temperatures. Thus, even at very high densities, the solution presents clusters of structured water particles surrounding solute inert particles, in a region in which pure solvent would be free of structure. Solute intercalates with solvent, a feature which has been suggested by experimental and atomistic simulation data. Examination of solute solubility has yielded a minimum in that property, which may be associated with the minimum found for noble gases. We have obtained a line of minimum solubility (TmS) across the phase diagram, accompanying the line of maximum in density (TMD). This coincidence is easily explained for non-interacting solute and it is in agreement with earlier results in the literature. We give a simple argument which suggests that interacting solute would dislocate TmS to higher temperatures

The Lista APDIS Online: a new vision for an existent service

The Lista APDIS Online (LAO) is a platform for scientific journals in Portuguese health science libraries launched in 2002, allowing efficiency in Inter-library loan services, journals searching, copy requests and their management among institutions. The evolution to a new version was essential. To develop and implement this new platform, the workflow of technical development was defined and the processes of upgrade and migration from the previous to the new database planned. Besides all functionalities of the previous version, the new version has a new database structure, a renewed layout, the ability forf libraries to update their contents and the existence of a user workstation allowing catalog search and requests. Success is predictable by over 1600 orders in only 5 months