4,237 research outputs found

    Assessment of a Hydrogen-Fueled Heavy-Duty Yard Truck for Roll-On and Roll-Off Port Operations

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    The port-logistic industry has a significant impact on the urban environment nearby ports and on the surrounding coastal areas. This is due to the use of large auxiliary power systems on ships operating during port stays, as well as to the employment of a number of fossil fuel powered road vehicles required for port operations. The environmental impact related to the use of these vehicles is twofold: on one hand, they contribute directly to port emissions by fuel consumption; on the other hand, they require some of the ship auxiliary systems to operate intensively, such as the ventilation system, which must operate to remove the pollutants produced by the vehicle engines inside the ship. The pathway to achieve decarbonization and mitigation of energy use in ports involves therefore the adoption of alternative and cleaner technology solutions for the propulsion systems of such port vehicles. This paper presents the performance analysis of a hydrogen powered cargo-handling vehicle for roll-on and roll-off port operations in a real case scenario. The fuel cell/battery hybrid powertrain of the vehicle has been previously designed by the authors. On the base of real data acquired during an on-field measurement campaign, and by means of a validated numerical model of the vehicle dynamics, different mission profiles are defined, in terms of driving and duty cycles, in order to represent typical port operations. A rule-based energy management strategy is then used to estimate the energy and hydrogen consumptions required by the vehicle and to assess its suitability to accomplish the defined target port operations. Outputs from this study show the potential of the proposed solution to take the place, in a foreseeable future, of conventional Diesel-engine vehicles, today commonly used in port logistics, towards a zero-emission scenario

    Assessment of ageing effect on the mechanical behaviour of steel/aluminium self-piercing riveted joint

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    Self-piercing riveting (SPR) is a new performing technology able to joint several kinds of metal and non-metal supports together. The combined effect of joint configuration and environmental conditions could have detrimental effect on the ageing effect on mechanical behaviour of dissimilar metal SPR joints. The joining of dissimilar materials, such as steel and aluminium, realized by self-piercing riveting (SPR) technique was studied to evaluate the ageing effects on its mechanical behaviour in critical environmental conditions. The investigation was carried out on symmetrical or unsymmetrical joints at varying total thicknesses (i.e. 2.0, 2.5 and 3.0 mm). The joint resistance was determined by single-lap shear tests. A design of experiment (DoE) has been performed by using Minitab® followed by the statistical analysis (ANOVA) of the experimental data. Long-term ageing tests in salt spray environment were performed to evaluate the durability of the mechanical joint. The experimental results evidenced that the corrosion degradation phenomena influenced significantly both the performance and failure mechanisms of the joints; also, the joint configuration is a significant factor for the corrosion effect. In the salt spray, the aluminium sheet undergoes a noticeable degradation due to galvanic Al/Fe corrosion. The set characterized by thinner aluminium sheet evidenced a gradual reduction of the mechanical strength with increasing ageing time due to the prevalence of thinning induced by aluminium corrosion. Instead, for S10-A15 samples (characterized by a thicker thickness of aluminium sheet) during the first 7 weeks, stable mechanical performances were observed. The experimental results evidenced that the corrosion degradation phenomena influence significantly both performances and failure mechanisms of SPR joints. Furthermore, the durability of the SPR joint is strongly affected by the joint configuration, and the best results were observed in the unsymmetrical joint with thicker aluminium sheet

    Frequent use of emergency departments: an application to the paediatric context.

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    Frequent users of Emergency Departments (EDs) represent a particularly interesting category of users since they account to a small percentage of patients but they affect considerably accesses, overcrowding and the overall costs of ED activities. The literature on the topic is vast and it allows to delineate a profile of frequent users identifying socio-demographic (age, gender, nationality) and clinical (chronic diseases, drugs and alcohol abuse; psychic illnesses) risk factors. However, most of the studies on the topic limit the analysis to one-year period or to a single study site and there is no consensus on the definition of frequent use. Frequent users are generally defined as those patients reporting a number of accesses per year beyond a certain threshold. The selection of the threshold is often based on previous literature or on percentiles but the definitions vary considerably and the choice tends to be subjective. In this study, the focus will be placed on paediatric patients, with reference to which the contributions in the literature are still very limited. The objective is to identify the most important drivers of ED frequent use in the 19 EDs of Liguria region (Italy) during a three-year period (2013-2015). The dataset contains 287,242 accesses referred to 144,895 under 14 patients and it includes information on patients\u2019 characteristics and on their clinical pathway. To overcome the limitations connected to previous definitions of frequent use, we exploit the availability of data on three years; this allows to define, not only frequent use, but also its duration (i.e. One-shot / Multiple shot frequent use) and intensity (Normal, High, Very high). By the use of logit and multinomial logit regressions we identify a set of risk factors associated to frequent use and to the different forms of frequent use. Results show that even if frequent users represent a small share of patients (9%) they contribute to roughly 25% of accesses. Chronic conditions are the most relevant determinants of frequent use (particularly mental disorders, diseases of the respiratory system) but also foreign nationality turns out to be an important predictor. Differences emerge in the impact of regressors on the different forms of frequent use defined according to its duration and intensity. The study represents an important tool to support policy-making and to discriminate between the potentially preventable frequent use (i.e. inapFrequent users of Emergency Departments (EDs) represent a particularly interesting category of users since they account to a small percentage of patients but they affect considerably accesses, overcrowding and the overall costs of ED activities. The literature on the topic is vast and it allows to delineate a profile of frequent users identifying socio-demographic (age, gender, nationality) and clinical (chronic diseases, drugs and alcohol abuse; psychic illnesses) risk factors. However, most of the studies on the topic limit the analysis to one-year period or to a single study site and there is no consensus on the definition of frequent use. Frequent users are generally defined as those patients reporting a number of accesses per year beyond a certain threshold. The selection of the threshold is often based on previous literature or on percentiles but the definitions vary considerably and the choice tends to be subjective. In this study, the focus will be placed on paediatric patients, with reference to which the contributions in the literature are still very limited. The objective is to identify the most important drivers of ED frequent use in the 19 EDs of Liguria region (Italy) during a three-year period (2013-2015). The dataset contains 287,242 accesses referred to 144,895 under 14 patients and it includes information on patients\u2019 characteristics and on their clinical pathway. To overcome the limitations connected to previous definitions of frequent use, we exploit the availability of data on three years; this allows to define, not only frequent use, but also its duration (i.e. One-shot / Multiple shot frequent use) and intensity (Normal, High, Very high). By the use of logit and multinomial logit regressions we identify a set of risk factors associated to frequent use and to the different forms of frequent use. Results show that even if frequent users represent a small share of patients (9%) they contribute to roughly 25% of accesses. Chronic conditions are the most relevant determinants of frequent use (particularly mental disorders, diseases of the respiratory system) but also foreign nationality turns out to be an important predictor. Differences emerge in the impact of regressors on the different forms of frequent use defined according to its duration and intensity. 150 05 March 2018, IISES Annual Conference, Sevilla ISBN ISBN 978-80-87927-45-8, IISES The study represents an important tool to support policy-making and to discriminate between the potentially preventable frequent use (i.e. inapFrequent users of Emergency Departments (EDs) represent a particularly interesting category of users since they account to a small percentage of patients but they affect considerably accesses, overcrowding and the overall costs of ED activities. The literature on the topic is vast and it allows to delineate a profile of frequent users identifying socio-demographic (age, gender, nationality) and clinical (chronic diseases, drugs and alcohol abuse; psychic illnesses) risk factors. However, most of the studies on the topic limit the analysis to one-year period or to a single study site and there is no consensus on the definition of frequent use. Frequent users are generally defined as those patients reporting a number of accesses per year beyond a certain threshold. The selection of the threshold is often based on previous literature or on percentiles but the definitions vary considerably and the choice tends to be subjective. In this study, the focus will be placed on paediatric patients, with reference to which the contributions in the literature are still very limited. The objective is to identify the most important drivers of ED frequent use in the 19 EDs of Liguria region (Italy) during a three-year period (2013-2015). The dataset contains 287,242 accesses referred to 144,895 under 14 patients and it includes information on patients\u2019 characteristics and on their clinical pathway. To overcome the limitations connected to previous definitions of frequent use, we exploit the availability of data on three years; this allows to define, not only frequent use, but also its duration (i.e. One-shot / Multiple shot frequent use) and intensity (Normal, High, Very high). By the use of logit and multinomial logit regressions we identify a set of risk factors associated to frequent use and to the different forms of frequent use. Results show that even if frequent users represent a small share of patients (9%) they contribute to roughly 25% of accesses. Chronic conditions are the most relevant determinants of frequent use (particularly mental disorders, diseases of the respiratory system) but also foreign nationality turns out to be an important predictor. Differences emerge in the impact of regressors on the different forms of frequent use defined according to its duration and intensity. 150 05 March 2018, IISES Annual Conference, Sevilla ISBN ISBN 978-80-87927-45-8, IISES The study represents an important tool to support policy-making and to discriminate between the potentially preventable frequent use (i.e. inapappropriate use) and that associated to complex medical conditions, such as chronic conditions

    Identification of predatory arthropods of the invasive Halyomorpha halys through molecular gut content analysis

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    Halyomorpha halys (StĂĄl, 1855) is an invasive agricultural pest in North America and Europe. Most of the information on H. halys predators in invaded areas comes from North America. This work focused on the molecular identification of arthropod predator species capable of feeding on H. halys in northern Italy. Predatory arthropods were collected in the field in four urban parks using the tree-beating technique. A real-time PCR workflow was applied to detect H. halys DNA from the gut content of predators. Of the 190 predator individuals analysed, 46 were positive for H. halys DNA and belonged to 10 insect taxa (1 Dermaptera, 3 Coleoptera, 2 Hemiptera and 4 Orthoptera) and six arachnid taxa (2 Opiliones and 6 Araneae). The integration of gut content analysis with laboratory bioassays and field observations allows the identification of a greater number of predators and therefore a better understanding of how the invaded ecosystem is responding to the introduction of a new species, given that samples are taken from the invaded environment itself. Therefore, the gut content analysis provides essential elements for conservation biocontrol in integrated pest management programmes

    Benthic foraminifera as environmental indicators in extreme environments. The marine cave of Bue Marino (Sardinia, Italy)

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    The coast of the Gulf of Orosei (Sardinia, Italy) consists of impressive cliffs set up on dolostones and limestones characterized by wide karst systems connected to the sea. Marine caves, which are part of these system flooded by seawater through marine entrances, may be considered as extreme environments because of wide spatial and temporal environmental variability due to changing marine and terrestrial contributions. This study presents the results of the third survey carried out in summer 2016 in the Bue Marino cave, as part of a research project started in 2014 aimed at the application of Benthic Foraminifera (BF) as ecological indicators in Mediterranean marine caves for the identification of different habitats and their environmental interpretation. Sediment and water samples were collected from a total of 25 stations from two distinct sectors of the cave (North Branch and Middle Branch); sediments were analysed for living and dead BF and grain size, while Temperature, Salinity, pH and Dissolved Oxygen were measured in water samples collected close to sediment water interface. Two main foraminiferal assemblages, with distinct characteristics with respect to the typical Mediterranean shallow-water ones, were recognized by means of Hierarchical Cluster Analysis and Non-metric Multidimensional Scaling, and a Canonical Correspondence Analysis deduced their environmental significance. A well oxygenated, less saline environment with coarse bottom sediment, correlated with a mixed calcareous-agglutinated assemblage (Gavelinopsis praegeri, Rosalina spp., Eggerelloides advenus and Reophax dentaliniformis) with high species diversity (H-index 2.32–3.57) and low foraminiferal density, was exclusive of the North Branch. A scarcely oxygenated, more saline environment with fine bottom sediment enriched in vegetal debris was related to a prevalently agglutinated assemblage characterized by low species diversity (H-index 1.60–2.68), with high dominance of E. advenus (up to 83.6%) associated to Ammonia tepida, and high foraminiferal density, recognized in the Middle Branch. These different environments were interpreted considering the different modes of feeding the karst systems of the two branches. They also corresponded to two distinct ecozones, Entrance and Confluence, already recognized in earlier studies. The environmental significance of the foraminiferal ecozones recognized in this study and their comparison with the ones identified in the previous years, helped to consider the ecological zonation as a tool for detecting seasonal and, possibly, long term annual environmental variability in the marine system

    Surgical complications after pancreatic transplantation: A computed tomography imaging pictorial review

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    pancreatic transplantation should start with the evaluation of the arterial Y-graft, the venous anastomosis and the duodenojejunostomy. With regard to complications, CT allows for the identification of vascular complications, such as thrombosis or stenosis of blood vessels supplying the graft, the detection of pancreatic fluid collections, including pseudocysts, abscesses, or leaks, the assessment of bowel complications (anastomotic leaks, ileus or obstruction), and the identification of bleeding. The aim of this pictorial review is to illustrate CT findings of surgical-related complications after pancreatic transplantation. The knowledge of surgical techniques is of key importance to understand postoperative anatomic changes and imaging evaluation. Therefore, we first provide a short summary of the main techniques of pancreatic transplantation. Then, we provide a practical imaging approach to pancreatic transplantation and its complications providing tips and tricks for the prompt imaging diagnosis on CT.Pancreatic transplantation is considered by the American Diabetes Association and the European Association for the Study of Diabetes an acceptable surgical procedure in patients with type 1 diabetes also undergoing kidney transplantation in pre-final or end-stage renal disease if no contraindications are present. Pancreatic transplantation, however, is a complex surgical procedure and may lead to a range of postoperative complications that can significantly impact graft function and patient outcomes. Postoperative computed tomography (CT) is often adopted to evaluate perfusion of the transplanted pancreas, identify complications and as a guide for interventional radiology procedures. CT assessment afte

    A vegetations map of south America.

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