Dynamic Change Evaluation for Ontology Evolution in the Semantic Web

Changes in an ontology may have a disruptive impact on any system using it. This impact may depend on structural changes such as introduction or removal of concept definitions, or it may be related to a change in the expected performance of the reasoning tasks. As the number of systems using ontologies is expected to increase, and given the open nature of the Semantic Web, introduction of new ontologies and modifications to existing ones are to be expected. Dynamically handling such changes, without requiring human intervention, becomes crucial. This paper presents a framework that isolates groups of related axioms in an OWL ontology, so that a change in one or more axioms can be automatically localised to a part of the ontology

C3N4 for CO2 photoreduction: catalyst performance and stability in batch and continuous reactor

In this study, various C3N4 samples were prepared and characterized. CO2 photoreduction was carried out by using C3N4 as powder and coated on glass support in a batch reactor or embedded in a Nafion membrane in a continuous reacto

Nanochemistry aspects of titania in dye-sensitized solar cells

We analyze the main nanochemistry factors affecting photovoltaic performance in TiO2 employed as wide bandgap semiconductor in dye-sensitized solar cells (DSCs). What is the best morphology of the oxide? Which processes yield the required structures? Finally, putting the discussion in the context of the rapid evolution of photovoltaic technologies, we argue that new titania nanostructures will form the basic component of second-generation solar modules based on dye solar cells

The classical Lenz vector and the two-dimensional quantum harmonic oscillator

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FineCat : a meeting fostering progress in frontier research and sustainable development from and within Sicily

Scientific meetings on topics of socioeconomic and environmental global relevance such as the \u201cFineCat Symposium on heterogeneous catalysis for fine chemicals\u201d held in Sicily between 2012 and 2017 may actively promote sustainable development and progress in frontier research from and within developing areas of the world

N-TiO2 Photocatalysts highly active under visible irradiation for NOX abatement and 2-propanol oxidation

N-doped TiO2 powders were prepared by two different sol–gel methods. Samples were characterised by X-ray diffraction (XRD), BET specific surface area measurements (SSA), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR). XPS measurements revealed a signal at 400 eV assignable to nitrogen in the form of Ti N O. EPR signals are attributed to molecular NO trapped with cavities/defects possibly interacting with oxygen vacancies. The photocatalytic activity under UV and visible light was determined following the abatement of NOx and the photodegradation of 2-propanol in gas–solid systems. N-doped TiO2 showed a higher activity compared with the pristine commercial and home prepared samples under visible light irradiation. A good photoactivity in the abatement of both NOx and 2-propanol is also observed for mechanical dispersions of N-TiO2 in CaCO3 serving as a model in view of perspective application in photocatalytically active construction and architectural materials

Photocatalytic degradation of dyes by using a membrane reactor

Dyes are organic compounds used in textile, food and drug industries, and their abatement represents one of the main problems in the treatment processes because generally they are very stable toxic compounds. In this work, two commercial azo-dyes, i.e. Congo Red (C32H22N6Na2O6S2) and Patent Blue (C27H31N2NaO6S2), in aqueous solution were degraded in a photocatalytic membrane reactor by using TiO2 Degussa P25 as the catalyst. Different system con\ufb01gurations and irradiating sources were studied, and the in\ufb02uence of some operational parameters such as the pressure in the membrane cell and the initial concentration of the substrates was determined. A comparison between suspended and entrapped TiO2 was also done. The experimental results showed a satisfactory degradation ef\ufb01ciency of the photocatalytic membrane process. The in\ufb02uence of various parameters (e.g. feed concentration, recirculation rate) has been discussed to obtain high reaction rates, operating stability and high membrane rejection, both for substrates and by-products. Congo Red was photodegraded with higher rate under the same experimental conditions probably due to its higher adsorption onto the catalyst surface. It was possible to treat successfully highly concentrated solutions (500 mg/L) of both dyes by means of a continuous process obtaining good values of permeate \ufb02uxes (30\u201370 L/m2 h); this could be interesting for industrial applications. The reactor containing the suspended photocatalyst was signi\ufb01cantly more ef\ufb01cient than the reactor containing the catalyst entrapped into the membrane

Photocatalytic CO 2 Valorization by Using Ti O2 , ZrO2 and Graphitic Based Semiconductors

In this century, a broad scientific interest has been devoted to fulfill sustainable industrial processes and climatic change remediation. In this prospective, various green technologies have been studied to valorize CO 2• The aim of this research is the CO 2 reduction in presence of water by using the photocatalytic technology with nanomaterials as the photocatalysts. The present work overviews the main outcomes obtained by using graphitic and oxide based photocatalysts both in gas/solid and liquid/solid batch reactors under simulated solar light. In all gas/solid regime tests the major products detected were methane, carbon monoxide, and acetaldehyde