653 research outputs found

    Modelling tracer dispersion from landfills

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    Several wind tunnel experiments of tracer dispersion from reduced-scale landfill models are presented in this paper. Different experimental set-ups, hot-wire anemometry, particle image velocimetry and tracer concentration measurements were used for the characterisation of flow and dispersion phenomena nearby the models. The main aim of these experiments is to build an extensive experimental data set useful for model validation purposes. To demonstrate the potentiality of the experimental data set, a validation exercise on several mathematical models was performed by means of a statistical technique. The experiments highlighted an increase in pollutant ground level concentrations immediately downwind from the landfill because of induced turbulence and mean flow deflection. This phenomenon turns out to be predominant for the dispersion process. Tests with a different set-up showed an important dependence of the dispersion phenomena from the landfill height and highlighted how complex orographic conditions downwind of the landfill do not affect significantly the dispersion behaviour. Validation exercises were useful for model calibration, improving code reliability, as well as evaluating performances. The Van Ulden model proved to give the most encouraging results

    Testing a gravity-based accessibility instrument to engage stakeholders into integrated LUT planning

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    The paper starts from the concern that while there is a large body of literature focusing on the theoretical definitions and measurements of accessibility, the extent to which such measures are used in planning practice is less clear. Previous reviews of accessibility instruments have in fact identified a gap between the clear theoretical assumptions and the infrequent applications of accessibility instruments in spatial and transport planning. In this paper we present the results of a structured-workshop involving private and public stakeholders to test usability of gravity-based accessibility measures (GraBaM) to assess integrated land-use and transport policies. The research is part of the COST Action TU1002 “Accessibility Instruments for Planning Practice” during which different accessibility instruments where tested for different case studies. Here we report on the empirical case study of Rome

    The learning process of accessibility instrument developers: Testing the tools in planning practice

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    Many planning support tools have recently been developed aimed at measuring and mod- elling accessibility (Accessibility Instrument or AI). The main difficulty for tool developers is designing an AI that is at the same time technically rigorous and usable in practice. Measuring accessibility is indeed a complex task, and AI outputs are difficult to communi- cate to target end-users, in particular, because these users are professionals from several disciplines with different languages and areas of expertise, such as urban geographers, spa- tial planners, transport planners, and budgeting professionals. In addition to this, AI devel- opers seem to have little awareness of the needs of AI end-users, which in turn tend to have limited ability for using these tools. Against this complex background, our research focuses on the viewpoint of AI developers, with two aims: (1) to provide insights into how AI devel- opers perceive their tools and (2) to understand how their perceptions might change after testing their AI with end-users. With this in mind, an analysis of 15 case studies was per- formed: groups of end-users tested different AI in structured workshops. Before and after the workshops, two questionnaires explored the AI developers’ perceptions on the tools and their usability. The paper demonstrates that the workshops with end-users were crit- ical for developers to appreciate the importance of specific characteristics the tool should have, namely practical relevance, flexibility, and ease of use. The study provides evidence that AI developers were prone to change their perceptions about AI after interacting directly with end-users

    Urban Form and Sustainability: the Case Study of Rome

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    This paper investigates the relation between sustainability and urban form. To this aim a system of Land-Use and Transport Interactions (LUTI) models has been designed and applied to the metropolitan area of Rome, to understand the interdependence of key variables such as travel behavior, transport supply, property values, jobs and residential location. The models represent the behavior of both dwellers and transport users and how they react to changing conditions. A system of assessment indicators has been defined to systematically test and compare alternative scenarios of urban form and to evaluate to what extent different locations and density distributions of activities achieve sustainability in terms of transport performances, social and environmental impacts

    Five years on: research, development and changing practice

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    Observations on the reproductive cycle, age and growth of the salema, <em>Sarpa salpa</em> (Osteichthyes: Sparidae) along the western central coast of Italy

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    La maduración sexual y crecimiento de Sarpa salpa (Linnaeus, 1758) en las costas del Mediterráneo italiano (Italia central) fueron estudiadas a partir de la recolecta de ejemplares muertos accidentalmente (n = 105) como consecuencia de las explosiones submarinas acaecidas durante la construcción del puerto de Civitavecchia en 1999, así como de ejemplares recolectados mediante redes de arrastre (n = 339). Esta especie se caracteriza por un hermafroditismo protándrico, ocurriendo el proceso de cambio sexual entre los 24 y 31 cm TL, los cuales corresponden a un amplio rango de edades (3-7 años). La talla de maduración (L50) fue de 19,5 cm, siendo la casi la totalidad de los individuos eran de sexo masculino. Se observaron dos períodos diferentes de reproducción: uno en primavera, de marzo a mayo y otro en otoño, de finales de septiembre a noviembre. Se observó, durante el primer año, un crecimiento compensatorio ocurrido entre los individuos nacidos en los dos períodos. Se identificó en los otolitos un modelo anual y regular de deposición de anillos. Se observó el depósito de un anillo translúcido durante los meses invernales, mientras que otro opaco se formó durante los meses de verano. Las composición por edades y tallas retrocalculadas se utilizaron para estimar los parámetros de la ecuación de crecimiento de Von Bertalanffy, es decir: L∞ = 37,27 cm, K = 0,27 año-1 y t0 = -0,53 año. S. salpa demostró un crecimiento isométrico (b = 3,04; P = 0,84; t = 0,19)

    Experimentation of a PVA-Borax hydrogel for the removal of Paraloid B72® from artifacts of archaeological interest from the National Archaeological Museum in Naples, Italy

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    This paper shows the results of an experimentation aimed at the removal of a polymeric film of aged Paraloid B72® originally placed to protect some wooden artifacts belonging to the Egyptian collection of the National Archaeological Museum of Naples (MANN). The study was conducted on two shabtis dated to the 19th Dynasty and a sculpture of Ptah-Sokar-Osiris dating to the late period. Thanks to the collaboration between the National Archaeological Museum of Naples and the Laboratory of Restoration of Wooden Artifacts of the University of Naples Suor Orsola Benincasa, it was possible to conduct an in-depth study of the artifacts, from both an archaeological-historical point of view and from a conservation point of view. This led to the development of the above-mentioned experimentation and to the planning of a proper restoration intervention. The study and experimentation were supported by several diagnostic techniques. In a first stage, non-invasive investigations were carried out to study the execution technique and the state of conservation of the artifacts. This allowed the recognition of the wood species that constituted the three sculptures through optical microscopy, whereas IR reflectography, UV induced fluorescence and X-ray radiation (XRF) were conducted to identify the type and the chemical nature of the pigments. Based on the above analysis, different restoration strategies, based on the removal of Paraloid B72® through a methodology that would act in full respect of the wooden support of the artifacts, were considered. Pros and cons of the different methodologies applied in the recent past for the removal of aged Paraloid from artifact surfaces were analysed. A removal technique based on the use PVA-Borax hydrogel loaded with a solvent mixture was selected. Experiments were conducted to validate the effectiveness of the selected method

    DNA metabarcoding of trawling bycatch reveals diversity and distribution patterns of sharks and rays in the central Tyrrhenian Sea

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    Conservation and management of chondrichthyans are becoming increasingly important, as many species are particularly vulnerable to fishing activities, primarily as bycatch, which leads to incomplete catch reporting, potentially hiding the impact on these organisms. Here, we aimed at implementing an eDNA metabarcoding approach to reconstruct shark and ray bycatch composition from 24 hauls of a bottom trawl fishing vessel in the central Mediterranean. eDNA samples were collected through the passive filtration of seawater by simple gauze rolls encapsulated in a probe (the "metaprobe"), which already showed great efficiency in detecting marine species from trace DNA in the environment. To improve molecular taxonomic detection, we enhanced the 12S target marker reference library by generating sequences for 14 Mediterranean chondrichthyans previously unrepresented in public repositories. DNA metabarcoding data correctly identifies almost all bycaught species and detected five additional species not present in the net, highlighting the potential of this method to detect rare species. Chondrichthyan diversity showed significant association with some key environmental variables (depth and distance from the coast) and the fishing effort, which are known to influence demersal communities. As DNA metabarcoding progressively positions itself as a staple tool for biodiversity monitoring, we expect that its melding with opportunistic, fishery-dependent surveys could reveal additional distribution features of threatened and elusive megafauna
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