1,945 research outputs found

    Passive house optimization for Southern Italy based on the “New Passivhaus Standard”

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    The IEE Passive-On project has drafted a proposal to adapt that Standard to the conditions that characterize Southern Europe, which is described in this paper together with its rationale. Compared with the original definition, one of the main changes is the introduction of explicit requirements on internal comfort during summer, in parallel to a limit to energy needs for cooling. The dynamic simulations conducted to test the new definition of the Standard in the context of Southern Italy (e.g. Palermo) show that the requirements identified by the Passivhaus Standard can be met by simplifying the envelope technologies (e.g. relaxing air-tightness design value) used in the context of Central Europe and adopting passive cooling strategies appropriately adjusted. Some simplifications of the ventilation system can be compensated by an increased role of thermal insulation of the building envelope and some of the choices can make energy needs tend to zero. In accordance with EN15251, thermal comfort is characterized according to Fanger’s PMV in cases where mechanical cooling is still required for peak situations, and according to the adaptive model where no mechanical cooling is required

    Image restoration using the Q-Ising spin glass

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    We investigate static and dynamic properties of gray-scale image restoration (GSIR) by making use of the Q-Ising spin glass model, whose ladder symmetry allows to take in account the distance between two spins. We thus give an explicit expression of the Hamming distance between the original and restored images as a function of the hyper-parameters in the mean field limit. Finally, numerical simulations for real-world pictures are carried out to prove the efficiency of our model.Comment: 27pages, 13figures, revte

    Digital business models in cultural tourism

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    Purpose Digitalization had a relevant impact on the cultural tourism sector, both demand and supply. If, on the one hand, advances in digital technologies provided tourists with new mobile services able to amplify the cultural experience, on the other hand, they catalyzed the development of new business models by digital enterprises. This paper has a twofold purpose: to detect business models and key characteristics of mobile apps for cultural tourism and to analyze the offering of app-based services in this sector. Design/methodology/approach The authors defined a methodology to identify, characterize and analyze a particular category of digital products for cultural tourism: app-based services. They are studied in terms of value creation, proposition and capture with the aim to identify the distinctive features of business models. As a result, the authors identified a classification framework on three main dimensions, namely "how to exploit mobile app features to create value for cultural tourists" (value creation), "which valuable services are delivered to cultural tourists" (value proposition) and "how companies are rewarded for the value they offered" (value capture). The authors apply the framework to perform a situation analysis of app-based services in the cultural tourism market. Findings The analysis highlights that digital enterprises offering app-based services do not fully exploit advances in technologies about users' value requirements. Hence, the results of our work suggest some directions that digital enterprises may follow to better exploit mobile app technology. Originality/value To date, little research has been devoted to investigating cultural tourism business models involving the exploitation of mobile app-based services. This research provides a useful framework to analyze fundamental aspects of business models in this sector. Such a framework represents a practical tool that provides fruitful insights for the design of a new generation of app-based services within the so-called "Internet of things" domain

    Application of the quantum spin glass theory to image restoration

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    Quantum fluctuation is introduced into the Markov random fields (MRF's) model for image restoration in the context of Bayesian approach. We investigate the dependence of the quantum fluctuation on the quality of BW image restoration by making use of statistical mechanics. We find that the maximum posterior marginal (MPM) estimate based on the quantum fluctuation gives a fine restoration in comparison with the maximum a posterior (MAP) estimate or the thermal fluctuation based MPM estimate.Comment: 19 pages, 9 figures, 1 table, RevTe

    Light inhibition of nitrification in sea-surface films

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    Nitrifying bacteria (ammonia- and nitrite-oxidizers) were isolated from sea-surface films collected in the Gulf of California. Laboratory studies indicate substrate oxidation by these isolates is inhibited by light. Ammonia-oxidizers showed lower nitrifying activity and a longer lag time when held in an 8-hr light:16-hr dark regime compared to those held completely in the dark, and nitrite-oxidizers showed nitrifying activity only when held in the dark. Tracer studies using 15N-ammonia corroborate that little or no nitrification occurs in the surface films of subtropical seas

    Porosity and crystal morphology of heterometallic coordination networks from β-diketonate ligands

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    Porous coordination polymers (PCPs) or metal-organic-frameworks (MOFs) are considered very promising porous materials that can be exploited in many different technological fields such as gas storage, heterogeneous catalysis and separation of mixtures. In the field of MOF materials, many efforts are devoted to the search of rational synthetic procedures. Among others, a useful synthetic strategy is the so-called Metalloligand (MLs) approach. MLs are coordination complexes containing suitably oriented exo donor-groups that, used in place of organic linkers, can orient the formation of desired homo and heterometallic polymeric architectures [1]. Functionalized chelating ligands suited to obtain useful MLs are \uf062-diketonate molecules.[2] We report the synthesis and the structural characterization of two families of coordination frameworks obtained through the use of different \uf062-diketonate ligands with copper salts of several counter-ions. The first family of polymers have a two-dimensional layered structure whereas the members of the second family adopt a three-dimensional flexible framework structure. We have focused our attention to the correlations between the crystal structure, the dimensionality, the topology and porosity of the networks and the crystal morphologies, as well as to the investigation of the surface phenomena during the crystal growing process. Moreover, we have mapped a continuous set of crystal morphologies by controlling experimental variables such as the solvent system, the metal-ligand molar ratio and the nature of the counter-anion. The aim is to develop a method to tune the crystal habit according to the specific requirement of some important applications.[3] [1] S. Kitagawa, R. Kitaura, S. Noro Angew. Chem., Int. Ed., 43 (2004) 2334. [2] L. Carlucci, G. Ciani, S. Maggini, D.M. Proserpio, M. Visconti, Chem. Eur. J, 16 (2010) 12328. [3] L. Carlucci, G. Ciani, J. M. Garc\ueca-Ruiz, M. Moret, D. M. Proserpio and S. Rizzato , Cryst. Growth Des., 2009, 9(12), 5024-5034
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