239 research outputs found

    A decision support system based on Electre III for safety analysis in a suburban road network

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    The aim of this paper is to develop a method for supporting decision makers in transport planning. When funds are insufficient to cover the interventions required to ensure safe driving conditions, it is necessary to optimize resources for the most critical sections. In this analysis, the multicriteria ranking method based on the ELECTRE III algorithms is applied to a real case, involving different sections of a motorway. This analysis is based on a comparison of different road sections in regard to safety conditions. The rank of more critical sections identifies intervention priorities

    A decision support system for road safety analysis

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    The aim of this paper is to develop a procedure for supporting public administrations in planning safety interventions on the road network. Road safety conditions depend on several factors, represented by a variety of quantitative and qualitative data, including: number of traffic accidents, traffic flow, lane width, shoulder width, road curvature and grade, access-point density, road markings and road signs (Mooren et al., 2012; OECD, 2002). By analysing a set of given roads or different sections of the same road, each with specific safety conditions, this methodology allows to determine which sections require interventions to improve safe driving conditions. Specifically, the multicriteria analysis technique is used in decision-making processes to support the choice among different alternatives in complex problems (Fadda, 2002). Among the different multicriteria techniques available, the Concordance Analysis will be used here. This paper proposes a unique modelling tool that incorporates the different indicators to calculate safety conditions. The methodology has been applied to a real case study for evaluating road safety on sections of a motorway infrastructur

    Decision-Making for Maritime Networks: Evaluating Corporate and Social Profitability of an Integrated Short Sea Shipping Network in the Upper Tyrrhenian Sea

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    This study applies cost benefit analysis (CBA) approaches to evaluate corporate and social profitability of a coordinated management proposal for a Short Sea Shipping (SSS) network in the upper Tyrrhenian area. The profitability of the maritime network is assessed first for the shipping companies operating therein and then for society as a whole. Corporate profitability analysis reveals a supply system currently over-sized compared to actual demand. The reasons for this must be found in the corporate competition strategies that traditionally characterize the free maritime transport market in the area. Social profitability analysis proves the potential positive impact of services rescheduling and coordination in terms of time savings and emission reduction in port areas and demonstrates the benefits new integrated management policies could yield for achieving higher efficiency and sustainability in SSS Tyrrhenian networks

    Planning and design support tools for walkability: a guide for urban analysts

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    We present a survey of operational methods for walkability analysis and evaluation, which we hold to show promise as decision-support tools for sustainability-oriented planning and urban design. An initial overview of the literature revealed a subdivision of walkability studies into three main lines of research: transport and land use, urban health, and livable cities. A further selection of articles from the Scopus and Web of Science databases focused on scientific papers that deal with walkability evaluation methods and their suitability as planning and decision-support tools. This led to the definition of a taxonomy to systematize and compare the methods with regard to factors of walkability, scale of analysis, attention on profiling, aggregation methods, spatialization and sources of data used for calibration and validation. The proposed systematization aspires to offer to non-specialist but competent urban analysts a guide and an orienteering, to help them integrate walkability analysis and evaluation into their research and practice

    Walkability and street intersections in rural-urban fringes: a decision aiding evaluation procedure

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    We propose a decision-aiding evaluation procedure (i) for classifying road crossings based on their impact on walkability and, subsequently, (ii) for prioritising street improvements, in urban-rural fringe areas. In the peripheral urban-rural fringes, pedestrian mobility is usually less developed and people generally depend more on cars for their everyday chores. Partly this is inevitable given the structural features and supply of services and activities in such areas, but part is due to a frequent neglect of pedestrian mobility in planning and urban design. Measures to improve this state of affairs can include the design of more pedestrian-friendly environments offering to potential users a greater level of security, comfort and convenience when walking to their designated destinations. Our evaluation procedure combines a walkability assessment methodology with the ELECTRE TRI rating procedure, in order to assist planners and decision makers in designing physical streets to enhance the continuity, safety and quality of pedestrian paths. Improving the walking accessibility in the fringe areas of towns is a way to reduce the physical and perceptual distance which separates these contexts from the rest of the city, thus leading to a progressive integration of urban functions

    A new management scheme to support reverse logistics processes in the agrifood distribution sector

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    During the last decades, reverse logistics and reuse of products have received growing attention as profitable and sustainable business strategies. Looking at the agrifood distribution sector, every day thousands of agrifood stores throw away large quantities of food product no longer suitable for sale. This "waste product", in the majority of cases, could still find new uses as animal feed or fertilizer. The return flow of food product is a typical problem of reverse logistics. This study proposes a new bi-modular scheme for managing the process of collection of "food waste" resulting from the agribusiness distribution sector and its subsequent distribution to livestock farms and collection centers located in the area of interest. The proposed management scheme consists of two modules: - module 1: to cluster the observed area into convenient collection sectors by means of clustering algorithms; - module 2: to identify optimal retrieval routes within each cluster by using Vehicle Routing models. The province of Cagliari in Sardinia (Italy) has been identified as test area. An extensive data collection process has been performed in order to collect the information necessary to portray the existing scenario. The following businesses have been recorded: grocery stores and supermarkets with at least 400 sqm of retail area, livestock farms with at least 200 heads of cattle, feed mills. A number of variables concerning location, type, size and demand data have been collected for each recorded unit.The management scheme has been implemented in a software platform and successfully applied in the test area. The outcome provides useful insights to stakeholders and suggests avenues for further research in the area in order to develop a more general and intuitive tool for managing reverse logistics processes in agrifood chains

    Multi-Analytical Techniques to Define the Mineralogical and Petrophysical Characteristics and Provenance of Siliceous Lithic Findings: The Case Study of La Calvera Rock Shelter (Cantabria, Spain)

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    This archaeometric study aims at characterizing the archaeological finds belonging to the lithic industry from La Calvera rock shelter (Camaleño, Cantabria) and at hypothesizing the possible provenance of each material. The site, located in the mountainous area of Picos de Europa National Park (more than 1000 m a.s.l.) close to the megalithic complex of Peña Oviedo, is characterized by the presence of hearths and charcoal remains, ancient pottery, and a rich lithic assemblage composed of siliceous rocks dating back to >8000 BP and linked to the first Holocene occupations of the Cantabrian Mountains. For the study of the rock shelter’s lithic assemblage, a multi-analytical approach was used: SEM-EDS and XRD analyses were performed to define the microtextural characteristics of samples and to identify the amorphous/crystalline phases; physical and mechanical tests were conducted to define the petrophysical properties (density, porosity, imbibition and saturation indexes, mechanical strength) of the samples. Preliminary data of chemical compositions, obtained by portable XRF, are also presented. The results show that the different siliceous materials (quartzite, cherts, hyaline quartz) can be distinguished through the basic analytical techniques used here. In addition, most of the archaeological samples have mineralogical and petrographic features similar to the natural samples coming from nearby outcrops, corroborating the hypothesis of a local material supply. The presence of local sources of useful raw materials could have favoured the site’s occupation. Finally, the diverse compositional and textural feature of the analysed materials result in different mechanical properties (porosity, density, hardness, workability), so they likely had different uses and technical functions

    From mining wastes to mineral sources - investigating the REE-bearing occurrences in the Arburèse District (SW Sardinia)

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    In recent years, the search for possible sources of REE minerals in Europe involved numerous old mine areas with high volumes of mining wastes that may offer significant amounts of Critical Raw Materials (CRMs). In some cases, strong evidence of CRMs anomalous concentrations arises from environmental characterization of wastes, so that an interesting problem is that of finding their sources, i.e., the original CRMs - rich mineral phases in the residual ore. An excellent example is provided by the Arburèse district of SW Sardinia, for about 150 years a major Pb-Zn source in Italy, now an area under study for remediation of its severe environmental problems, including >10 Mt of waste deposits. The district exploited a large system (>10 km) of low-temperature polymetallic veins hosted in Lower Paleozoic siliciclastic rocks belonging to the Variscan Nappe zone, arranged in two main geometrical trends relative to the late Variscan Arbus pluton: “peripheral” and “intersecting”. Recent investigations in the Montevecchio mine area discovered high Zn (up to 2.65 wt.%) and Pb (1.23 wt.%) grades in stratified tailing materials belonging to the Sanna old processing plant. Remarkably, ICP-MS analyses on the same materials revealed total REE+ Y contents attaining about 600 ppm. XRD studies confirmed a tailing composition essentially made of gangue minerals (quartz, siderite and micas) with goethite, baryte and traces of Zn carbonates and Pb sulfates. Chondrite-normalized REE patterns are coherent with the hydrothermal character of the source: however, both the REE mineralogical host(s) in tailings and in the Montevecchio ore are still undetermined. In the search of REE-bearing phases in the ores, some relevant insights are provided by studies on the southern branch of the Arburèse system, where the veins of “peripheral” system are hosted in late Ordovician-Silurian sedimentary sequences. In this part of the district the polymetallic veins assume the character of five-elements (Ni-Co-As-Bi-Ag) veins, with a rich Ni-Co-Fe arsenide – quartz association (1) overprinted by a Zn-Pb-Cu sulfide – siderite – quartz association (2), very similar to that dominating in Montevecchio. Investigations in the Pira Inferida mine sector highlighted the presence of LREE fluorocarbonates (synchysite-Ce and bastnaesite-Ce) and phosphates (monazite) associated with rutile and apatite. LREE minerals have been detected by SEM-EDS as tiny crystals in the quartz-sericitic gangue of the Montevecchio-type (2) mineral association. The same minerals are found in millimetric aggregates in the oxide zone of the veins, sporadically reported by mineral collectors in other mine sites of the same system. Overall, these occurrences, similar to those found in other low-temperature vein systems of Sardinia (e.g., Silius vein system), appear reliable mineral REE sources for Montevecchio mine wastes; they may be therefore used as proxies for REE exploration and assessment in the district

    Dissolved fluoride removal by OCP, a precursor of apatite

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    The consumption of water with fluoride concentration higher than 1.5 mg/L (WHO recommended limit) is recognized to cause serious diseases. Fluoride removal from natural contaminated waters is a worldwide priority for more than 200 million people. The octacalcium phosphate (OCP), a mineralogical precursor of bio-apatite, is here tested as a fluoride remover. A new two-step method for the synthesis of OCP is proposed; it consists of 1) synthesis of brushite from calcium carbonate and phosphoric acid and, 2) subsequent hydrolysis of brushite. Fluoride removal experiments were performed in batch-mode using 200 mg of OCP in 50 ml solutions with different initial concentrations of fluoride (from 40 to 140 mg/L). Most of fluoride is removed within the first two hours, whereas the WHO limit of 1.5 mg/L is reached within a minimum of 3 hours for a starting Fconcentration of 40 mg/L, and in about 12 hours for a starting F-concentration of 80 mg/L. One gram of OCP can remove up to 26 mg of fluoride. The pH of the solution after the treatment is within the range of drinking water. XRD characterization of the solid phases, before and after the experiments, indicates that OCP transforms into fluorapatite via Fremoval from solution
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