142 research outputs found

    Evaluating the impacts of urban freight traffic: application of micro-simulation at a large establishment

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    Heavy Goods Vehicles, HGV, and Light Goods Vehicles, LGV, are a significant contributor to air pollution problems in urban areas. This paper quantifies the contribution to the environment of the deliveries to a single, large city employer addressing a research gap in the literature. Analysis of data from comprehensive surveys carried out over two years demonstrated that freight delivery traffic generated by an urban establishment with multiple properties in a compact urban setting, is characterised by a high proportion of LGV consistent with recent national and international trends. Also, despite freight traffic is only 10% of local traffic, more than 50% serves the single establishment, suggesting a different approach to policy making driven by the employer should be explored. The modelling results showed, relatively, the largest contribution to total emissions comes from HGVs in the AM peak, 13.8%, 43.7%, 9.2% for CO2, NOx and PM respectively. LGV contribute less, with 5.5%, 3.8%, 6% for CO2, NOx and PM respectively but more responsible for local congestion due to their numbers. This research is the first known study of its type and with the unique combination of measurement and traffic microsimulation allowed consideration of more effective traffic management strategies as well as providing evidence to support a consolidation centre for deliveries outside the city with fewer electric or low emissions last mile vehicles reducing substantially the environmental impact. The research outputs are relevant to many other similar cases in UK and Europe. The paper contributes to the ongoing development of research and policy looking to achieve sustainable urban logistics through receiver and purchasing led initiatives

    Rolling resistance contribution to a road pavement life cycle carbon footprint analysis

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    Purpose Although the impact of road pavement surface condition on rolling resistance has been included in the life cycle assessment (LCA) framework of several studies in the last years, there is still a high level of uncertainty concerning the methodological assumptions and the parameters that can affect the results. In order to adopt pavement carbon footprint/LCA as a decision-making tool, it is necessary to explore the impact of the chosen methods and assumptions on the LCA results. Methods This paper provides a review of the main models describing the impact of the pavement surface properties on vehicle fuel consumption and analyses the influence of the methodological assumptions related to the rolling resistance on the LCA results. It compares the CO2 emissions, calculated with two different rolling resistance models existing in literature, and performs a sensitivity test on some specific input variables (pavement deterioration rate, traffic growth, and emission factors/fuel efficiency improvement). Results and discussion The model used to calculate the impact of the pavement surface condition on fuel consumption significantly affects the LCA results. The pavement deterioration rate influences the calculation in both models, while traffic growth and fuel efficiency improvement have a limited impact on the vehicle CO2 emissions resulting from the pavement condition contribution to rolling resistance. Conclusions and recommendations Existing models linking pavement condition to rolling resistance and hence vehicle emissions are not broadly applicable to the use phase of road pavement LCA and further research is necessary before a widely-used methodology can be defined. The methods of modelling and the methodological assumptions need to be transparent in the analysis of the impact of the pavement surface condition on fuel consumption, in order to be interpreted by decision makers and implemented in an LCA framework. This will be necessary before product category rules (PCR) for pavement LCA can be extended to include the use phase

    Prioritizing Vehicle Cleanliness (PVC) using Key Green Performance Indicators (KGPI)

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    Climate catastrophes (e.g. hurricane, flooding and heat waves) are generating increasing impact on port operations and hence configuration of shipping networks. This paper formulates the routing problem to optimise the resilience of shipping networks, by taking into account the disruptions due to climate risks to port operations. It first describes a literature review with the emphasis on environmental sustainability, port disruptions due to climate extremes and routing optimisation in shipping operations. Second, a centrality assessment of port cities by a novel multi-centrality-based indicator is implemented. Third, a climate resilience model is developed by incorporating the port disruption days by climate risks into shipping route optimisation. Its main contribution is constructing a novel methodology to connect climate risk indices, centrality assessment, and shipping routing to observe the changes of global shipping network by climate change impacts

    Macrostructural Alterations of Subcortical Grey Matter in Psychogenic Erectile Dysfunction

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    Psychogenic erectile dysfunction (ED) has been defined as the persistent inability to attain and maintain an erection sufficient to permit sexual performance. It shows a high incidence and prevalence among men, with a significant impact on the quality of life. Few neuroimaging studies have investigated the cerebral basis of erectile dysfunctions observing the role played by prefrontal, cingulate, and parietal cortices during erotic stimulation. In spite of the well-known involvement of subcortical regions such as hypothalamus and caudate nucleus in male sexual response, and the key role of nucleus accumbens in pleasure and reward, poor attention was paid to their role in male sexual dysfunction. In this study, we determined the presence of grey matter (GM) atrophy patterns in subcortical structures such as amygdala, hippocampus, nucleus accumbens, caudate nucleus, putamen, pallidum, thalamus, and hypothalamus in patients with psychogenic ED and healthy men. After Rigiscan evaluation, urological, general medical, metabolic and hormonal, psychological and psychiatric assessment, 17 outpatients with psychogenic ED and 25 healthy controls were recruited for structural MRI session. Significant GM atrophy of nucleus accumbens was observed bilaterally in patients with respect to controls. Shape analysis showed that this atrophy was located in the left medial-anterior and posterior portion of accumbens. Left nucleus accumbens volumes in patients correlated with low erectile functioning as measured by IIEF-5 (International Index of Erectile Function). In addition, a GM atrophy of left hypothalamus was also observed. Our results suggest that atrophy of nucleus accumbens plays an important role in psychogenic erectile dysfunction. We believe that this change can influence the motivation-related component of sexual behavior. Our findings help to elucidate a neural basis of psychogenic erectile dysfunction

    Multiple bowel perforations complicating imatinib treatment for advanced gastrointestinal stromal tumor

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    An 82-year-old woman presented with acute abdominal pain, vomiting, and fever (38.8°C). One year earlier, she had an advanced gastrointestinal stromal tumor (GIST) with multiple intestinal and endoperitoneal localizations, not suitable for operation. Since then, she was treated with imatinib-mesylate, 400 mg once daily. On examination, her abdomen was diffusely tender with bulky elastic masses palpable in the middle and lower abdomen. Laboratory tests revealed moderate anemia (Hb 9.8 g/dL) with a white blood cell count of 16,200. Plain supine x-rays of the abdomen apparently showed some fluid levels with a marked dilatation of a bowel loop, simulating a closed-loop mechanical obstruction (A). CT scan showed neither bowel distention nor fluid levels, but there were contrast leaks from the small bowel communicating with large cavities (B, arrows). Urgent surgery was warranted. Multiple large soft masses, covered by inflamed serosa and containing gas and fluid, were found adhering to the small-bowel wall at laparotomy (C, arrows). Small, solid, nodular lesions were diffusely disseminated over the bowel wall and onto the peritoneum. An extended small-bowel resection with en bloc excision of the lesions and entero-entero anastomosis 38
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