Search results for "2300"
showing 10 items of 92 documents
Comparative life-cycle assessment of conventional (double lane) and non-conventional (turbo and flower) roundabout intersections
2016
Abstract This research studied and compared different construction techniques for the road subgrade, embankment and pavement of different types of roundabout intersections in order to assess their environmental sustainability. A Life Cycle Assessment (LCA) was carried out on double lane, turbo- and flower roundabouts. We considered virgin materials and reclaimed asphalt pavement (RAP) for the pavement construction. Also the environmental effects due to in situ lime stabilization of fine-grained soils were assessed in order to reduce the use of virgin material in road subgrades. The use of reclaimed asphalt pavement (RAP) can lead to a significant reduction in pollutant emissions and energy …
SUP R DSS: A sustainability-based decision support & system for road pavements
2019
Road pavement community members are increasingly becoming aware of the need to incorporating the principles of sustainable development into the sector. Policies are also going in this direction and as a consequence in the recent years researchers and practitioners are coming up with new materials, technologies and practices designed to reduce the negative impacts of their activities in the surroundings. Within this framework the road pavements sector is witnessing a paradigm shift towards the development of pavement technologies incorporating high-content of recycled materials, as well as best practices to decrease the overall carbon footprint. These are all promising solutions that to the …
Nitrous oxide emission in a University of Cape Town membrane bioreactor: The effect of carbon to nitrogen ratio
2017
Abstract The effect of the carbon-to-nitrogen (C/N) ratio in the influent on the nitrous oxide (N 2 O) emission from a University of Cape Town Membrane BioReactor pilot plant was investigated. The membrane was located in a separate tank to single out the production of N 2 O due to the biological processes from N 2 O stripping as a result of the extra aeration needed for the mitigation of membrane fouling. The experimental campaign was divided into two phases, each characterized by a different C/N ratio (namely, 10 and 5 mgCOD/mgTN, Phase I and Phase II, respectively). The decrease of the C/N ratio promoted the increase of N 2 O emissions in both gaseous and dissolved phases, mainly due to a…
The effect of the solids and hydraulic retention time on moving bed membrane bioreactor performance
2018
Abstract The aim of the present paper was to investigate the effect of solids (SRT) and hydraulic (HRT) retention time on Integrated Fixed Film Activated Sludge (IFAS) University of Cape Town (UCT) membrane Bioreactor (MBR). In particular, three different pairs of SRT and HRT values were analysed, namely, Phase I 56 d/30 h, Phase II 31 d/15 h and Phase III 7 d/13 h. The short-term effect of these three SRT/HRT conditions was assessed by analysing several system performance indicators: organic carbon and biological nutrient (nitrogen and phosphorus) removal, biomass respiratory activity, activated sludge filtration properties and membrane fouling. The results showed that the decrease of SRT/…
Testing the USLE-M family of models at the Sparacia experimental site in south Italy
2017
The modified Universal Soil Loss Equation (USLE-M) was empirically deduced by a statistical analysis of the original data set of soil loss measurements used to derive the Universal Soil Loss Equation (USLE). The USLE-M, including the effect of runoffin the event rainfall-runofferosivity factor, is characterized by a better capacity to predict event soil loss. At first, in this paper, using the soil erosion representative variables of USLE-M and the reference condition adopted in the USLE, the dimensional analysis and the self-similarity theory are applied to theoretically deduce a multiplicative equation similar to the USLE-M. Then using the database of the Sparacia experimental site, the a…
Life cycle assessment of roads: Material and process related energy savings
2018
The need for climate change mitigation calls for significant actions to match the sustainable development goals and, in this context, road construction and management play a relevant role (cf. EU Green Public Procurement Criteria for Road Design, Construction and Maintenance and Environmental Product Declarations - EPD). In such a context, the role of the Life Cycle Assessment (LCA) methodology is broadly recognized as a tool to quantify sustainability of processes and systems. This study aims at calculating the life-cycle energy and carbon footprint of a typical Italian urban road, including materials production, transportation, construction, maintenance, and rehabilitation. The LCA approa…
Plant and stink bug interactions at different trophic levels
2017
The interactions between plants and herbivores are among the most important ecological interactions in nature (Johnson 2011). Plants are sessile organisms and cannot run away from potential attackers, which are range from pathogenic microbes to grazing mammals. Among these attackers, arthropods, and in particular insects, comprise the largest and most diverse group of organisms with approximately 1-3 million species feeding on plants (Schoonhoven et al. 2005, Dicke 2009). Host-finding and acceptance or rejection of plants by herbivorous insects depend on their behavioral responses to physical and chemical plant features (Finch and Collier 2000). In this context, the insect-plant interaction…
Review of push-out and shear response of hybrid steel-trussed concrete beams
2018
The hybrid steel trussed concrete beams examined in the present study are comprised of two principal components, i.e., a steel joist with inclined rebars, realized in industry, which is welded to a smooth steel plate and then embedded within the concrete cast in situ. The paper presents first the state of the art on laboratory tests and analytical modeling of the steel-to-concrete stress transfer mechanism investigated by push-out tests. Next, the most relevant scientific contributions currently available in the technical literature regarding experimental investigation on actual shear behavior are summarized and discussed. Lastly codes and analytical models are reviewed.
Rolling resistance contribution to a road pavement life cycle carbon footprint analysis
2016
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…
Are Farmers in Alternative Food Networks Social Entrepreneurs? Evidence from a Behavioral Approach
2015
Social entrepreneurship, individual activities with a social objective, is used in this study as a conceptual tool for empirically examining farmers’ participation in alternative food networks (AFNs). This study verifies whether their participation is driven by the social entrepreneurship dimension to satisfy social and environmental needs. We develop a more inclusive view of how social entrepreneurship is present among farmers participating in AFNs by using a behavioural approach based on three main psychological constructs: attitude, objective, and behaviour. The empirical results show that two types of farmers participate in AFNs. One type is closer to commercial entrepreneurs; the main …