Smart cities have been recently pointed out by M2M experts as an emerging market with enormous potential, which is expected to drive the digital economy forward in the coming years. However, most of the current city and urban developments are based on vertical ICT solutions leading to an unsustainable sea of systems and market islands. In this work we discuss how the recent vision of the Future Internet (FI), and its particular components, Internet of Things (IoT) and Internet of Services (IoS), can become building blocks to progress towards a unified urban-scale ICT platform transforming a Smart City into an open innovation platform. Moreover, we present some results of generic implementations based on the ITU-T's Ubiquitous Sensor Network (USN) model. The referenced platform model fulfills basic principles of open, federated and trusted platforms (FOTs) at two different levels: the infrastructure level (IoT to support the complexity of heterogeneous sensors deployed in urban spaces), and at the service level (IoS as a suit of open and standardized enablers to facilitate the composition of interoperable smart city services). We also discuss the need of infrastructures at the European level for a realistic large-scale experimentally-driven research, and present main principles of the unique-in-the-world experimental test facility under development within the SmartSantander EU project.

Herein, we describe a new class of porous composites comprising metal–organic framework (MOF) crystals confined in single spherical matrices made of packed covalent‐organic framework (COF) nanocrystals. These MOF@COF composites are synthesized through a two‐step method of spray‐drying and subsequent amorphous (imine‐based polymer)‐to‐crystalline (imine‐based COF) transformation. This transformation around the MOF crystals generates micro‐ and mesopores at the MOF/COF interface that provide far superior porosity compared to that of the constituent MOF and COF components added together. We report that water sorption in these new pores occurs within the same pressure window as in the COF pores. Our new MOF@COF composites, with their additional pores at the MOF/COF interface, should have implications for the development of new composites.

We present a density functional (DF) analysis for the entropic force in Atomic Force Microscopy (AFM) across the layers of a dense fluid. Previous theoretical analysis, based on the ideal gas entropy, was apparently supported by the similarity in the oscillatory decay for the force and density profile. We point out that such similarity is a generic DF result, which carries no information on the interface, since the decaying mode is characteristic of the bulk fluid correlation. The truly interfacial information, from the layering measured by AFM, comes in its amplitude and not in the decay mode. With our rigorous study of a simple hard sphere model, we find semiempirical clues to disentangle the role of the tip radius and to relate the amplitude of the molecular layering to the oscillatory force on the AFM tip.

We analyze the density correlations in a liquid-vapor surface to establish a quantitative connection between the Density Functional (DF) formalism, Molecular Dynamic (MD) simulations, and the Capillary Wave (CW) theory. Instead of the integrated structure factor, we identify the CW fluctuations as eigenmodes of the correlation function. The square-gradient DF approximation appears as fully consistent with the use of the thermodynamic surface tension to describe the surface fluctuations for any wavevector because it misses the upper cutoff in the surface Hamiltonian from the merging of the CW mode with the non-CW band. This mesoscopic cutoff may be accurately predicted from the main peak in the structure factor of the bulk liquid. We explore the difference between the full density-density correlation mode and the bare CW that represents the correlation between the corrugation of the intrinsic surface and the density at the interfacial region. The non-local decay of the CW effects, predicted from DF analysis and observed in MD simulations with the intrinsic sampling method, is found to characterize the bare CW fluctuations, which also require a wavevector-dependent surface tension.

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Abstract. The Smart City concept relates to improving efficiency of city services and facilitating a more sustainable development of cities. However, it is important to highlight that, in order to effectively progress towards such smart urban environments, the people living in these cities must be tightly engaged in this endeavour. This paper presents two novel services that have been implemented in order to bring the Smart City closer to the citizen. The Participatory Sensing service we are proposing exploits the advanced features of smartphones to make the user part of the ubiquitous sensing infrastructure over which the Smart City concept is built. The Augmented Reality service is connected to the smart city platform in order to create an advanced visualization tool where the plethora of available information is presented to citizens embedded in their natural surroundings. A brief description of the smart city platform on top of which these services are built is also presented.

Three-dimensional force microscopy generates atomically resolved 3D images of solid–liquid interfaces. Here, we investigated the components of the interfacial force exerted by a tip on a mica–liquid interface by comparing density functional theory and experiments. The study involved two liquids: an aqueous solution of KCl (polar) and n-octane as a nonpolar solvent. The comparison between theory and experiments shows the presence of oscillatory and monotonically decaying terms. The periodicity of the oscillation arises from entropic effects associated with the molecular packing of the liquid, while its amplitude carries information on the solid surface (substrate and tip)–liquid interactions. The exponent of the monotonic term comes from cohesive interactions between the liquid molecules, while its amplitude reflects the interactions with the solid surfaces.

Wertheim predicted strong density-density correlations at free liquid surfaces, produced by capillary wave fluctuations of the interface [M. S. Wertheim, J. Chem. Phys. 65, 2377 (1976)JCPSA60021-960610.1063/1.433352]. That prediction has been used to search for a link between capillary wave (CW) theory and density functional (DF) formalism for classical fluids. In particular, Parry et al. have recently analyzed the decaying tails of these CW effects moving away from the interface as a clue for the extended CW theory [A. O. Parry et al., J. Phys.: Condens. Matter 28, 244013 (2016)JCOMEL0953-898410.1088/0953-8984/28/24/244013], beyond the strict long-wavelength limit studied by Wertheim. Some apparently fundamental inconsistencies between the CW and the DF theoretical views of the fluid interfaces arose from the asymptotic analysis of the CW signal. In this paper we revisit the problem of the CW asymptotic decay with a separation of local non-CW surface correlation effects from those that are a truly nonlocal propagation of the CW fluctuations from the surface towards the liquid bulk.