293 research outputs found
Risk based characterization of a contaminated industrial site using multivariate and geostatistical tools
No full textHuman and ecological risk assessment requires the sources, distribution, mobility and environmental behaviour of contaminants
to be investigated on a site-speci®c basis. It often deals with data sets which are relatively small and a ected by sampling gaps. In
the case of a polycyclic aromatic hydrocarbon (PAH) contaminated industrial site, Kriging interpolation of spatial data and prin-
cipal component analysis (PCA) proved useful for extracting additional value from the data set. Kriging was adopted for assessing
the horizontal and vertical distribution and transport of PAHs in soil. PCA was applied to PAH concentration and relative abun-
dance in soil samples and interpreted on the basis of the PAH physico-chemical and bio-degradation properties. It revealed corre-
lation with the products of a neighbouring factory and the weathering of the lighter PAHs. The geo- and multivariate statistical
results were coupled with the previous hydrogeological characterisation of the site to develop a site-conceptual model for use in the exposure scenario modelling for risk assessment
Bayesian statistics-based procedure for sampling of contaminated sites
No full textA variable density sampling pattern based on Bayesian statistics is presented and compared to a uniform density statistical pattern and a judgmental approach in a real case study. The Bayesian statistics, supported by a software tool, supplied a soil sampling plan similar to the judgmental one, especially for the number of sampling points and their location. It allowed statistical goals to be set and expert judgment to be included in the sampling strategy in a transparent and systematic procedure. For these reasons, it appears quite suitable for inclusion into Quality Assurance Quality Control plans
Assessing the Impact of Changes in Mobility Behaviour to Evaluate Sustainable Transport Policies: Case of University Campuses of Politecnico di Milano
No full textStarted in 2011, the “Città Studi Campus Sostenibile” project (CSCS), promoted by Politecnico di Milano and Università degli Studi di Milano, is aimed at turning the common university district in a model for quality of life and environmental sustainability. One of the topics of this project relates with transport and sustainable mobility.
In this framework, during the last three years, the Sustainable Office of the University, in collaboration with the university mobility manager, carried out two surveys on mobility and commuting, among students, professors and administrative staff. In 2015 were surveyed about 12.000 people and about 14.000 in 2017, respectively 27% and 24% of the total population of each year.
Through the analysis of the data of the last survey, we firstly provide a description of the current mobility patterns of the university population, then we calculate CO2 emissions from mobility activities to access Politecnico campuses. In order to estimate CO2 emissions of every trip, we utilize local emission factors for each transport mode. Previous studies evidenced how this component accounts for more than 40% of the total emissions of Politecnico di Milano.
Lastly, in order to identify in which context policy packages, aimed at increasing the modal share of sustainable transport modes, are more effective and efficient in reducing CO2 emission, we analyse a set of scenarios involving both different territorial contexts inside Lombardy region and different campuses population
Quantification of thermal resilience in buildings: Evaluation of Building Envelope Performance and Operational Parameters
No full textClimate change and extreme heat are critical issues which have been faced all over the world. Consequently, designers strive to monitor and assess the performance of facades by developing environmental assessments at the early design stages, since design changes do not require many resources. Rapid urban expansion in many parts of the world is leading to increased exposure to extreme natural hazards, exacerbated by climate change. It is essential to come up with strategies for mitigating the vulnerability of the built environment. The concept of thermal resilience and adaptation to climate change have gained ground and international attention in the Architecture, Engineering and Construction (AEC) industry. Resilience is a multi-facet property which defines the vulnerability of the built environment. Although the qualitative assessment of resilience value, the quantification of urban resilience is not yet representative enough and there is a lack of calculating the resilience in the built environment. However, designers are called to develop building and planning proposals with taking into consideration the thermal resilience of buildings against extreme hazards. This thesis aims to fill the gap between the qualitative and quantitative evaluation of thermal resilience in buildings by considering the operational building performance and the thermal performance of the building envelope in case of extreme heat waves. Towards this direction, the most influential parameters of thermal resilience are identified by implementing a sensitivity analysis process, in the first part. Secondly, a quantification method is presented and the thermal resilience performance for buildings in Amsterdam is calculated. Last, this thesis attempts to develop a computational workflow in order to assist designers and engineers in defining the thermal resilience index from the early design stage. Defining a less computational cost and time-consuming workflow is also a goal. Due to time limitations, the multi-facet aspect of resilience and the difficulty of quantification of its indicators, this research focuses on the ex-ante evaluation of the building envelope by identifying its vulnerability to extreme heat waves.Architecture, Urbanism and Building Sciences | Borders and Territorie
3D Transesophageal echocardiography using a fast-rotating transducer
No full textEchocardiography is a diagnostic modality which is widely used in cardiology, using ultrasound to image the living heart and assess its physiological function. Three-dimensional echocardiography surpasses the visual limitations of conventional echocar-diography, offering a three-dimensional perspective of the heart. Traditional techniques for acquiring three-dimensional echocardiographic images have been successfully applied to the transesophageal approach to echocardiography. The important clinical contribution of three-dimensional transesophageal echocardiography (3D TEE), as well as the unique diagnostic opportunities it offers, have been acknowledged. However, the applied tech-niques are based on a slow procedure, cumbersome for the patient and present certain pit-falls. Recent technological advancements have allowed more flexible approaches to 3D TEE. Such approaches are, nonetheless, based on an expensive solution with inherent limitations, available only with specialized, high-end imaging systems. The present thesis is a description of the authors work on the realization of three-dimensional transesophageal echocardiography using a TEE probe with a fast-rotating transducer array. It describes the entire endeavor of visualizing the heart and its inherent structures in three dimensions by implementing a novel approach in transesophageal echocardiographic imaging. The approach itself and subsequent research to implement and optimize it are portrayed. The authors work was carried out in its entirety at the Biomedical Engineering department of the Thoraxcenter, Erasmus Medical Center, Rot-terdam, the Netherlands, within the Experimental Echocardiography group (ExpEcho) in close cooperation with Oldelft Ultrasound B.V (Oldelft), Delft, the Netherlands. The organizational structure of the thesis attempts to introduce the reader to back-ground knowledge necessary for understanding the subject, present the technical aspects involved and discuss the results and conclusions of the work. The first chapter establishes the background for concepts and terminology related to the thesis subject. In the second chapter, the details on resources and devices used are illustrated, connecting them with the work involved. Further, the design concepts are justified according to specific re-quirements of the approach. Chapters 3 and 4 describe the associated experimental work. The outcome of that work and its implications about the success of the initial concept are portrayed. The images in these two chapters which correspond to avi-files located in the accompanying CD-ROM are marked with the tag Video available. Finally, chapter 5 sum-marizes the results of the work, presenting certain conclusions extracted from that work. Suggestions regarding the future direction of research on the topic are provided.Electrical Engineering, Mathematics and Computer Scienc
Appunti per una edizione dell’ opera di Nilos-Nathanail Bertos
No full textAlthough the monk Nilos Bertos holds great importance in the context of the early literary production of Crete under Venetian rule, studies related to his life and work are very limited. Most of his writings (about 20 prose homilies and 3 verse compositions) are still unpublished. This contribution aims to analyze the current state of research on Bertos, highlight some unresolved issues, and promote a comprehensive revision of his life and works, with the goal of producing an updated critical edition that takes into account the entire tradition of his work, which is preserved in about twenty manuscripts
Validating the Simulated Impacts of Urban Freight Transport
No full textThis paper provides a comprehensive guide for assessing the impacts of an urban freight transport system through traffic simulation software. Based on a calibrated and validated city wide urban traffic model that integrates the freight trips of six freight vehicles in the examined day, aim of the paper is to establish an impact assessment framework that evaluates model’s environmental and transport impacts. The analysis of the freight trips showed that they account for 22009.2 g of CO2 emissions and 84.17 h of total network delays on a daily basis. Other impact assessment indicators’ values such as average vehicle speed, first attempt successful deliveries, freight vehicles’ number of roundtrips, load factor, utilization factor, emissions, traffic throughput, etc. were also computed. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG
Magnetic field structure in the vicinity of a supermassive black hole in low-luminosity galaxies: the case of Sgr A∗
No full textObservations of have provided a lot of insight on low-luminosity accretion, with a handful of bright flares accompanied with orbital motion close to the horizon. It has been proposed that gas supply comes from stellar winds in the neighborhood of the supermassive black hole. We here argue that the flow at the vicinity of the black hole has a low magnetization and a structure of alternating polarity, totally dictated by the well-studied and long-ago proposed MRI turbulent process. This can be the case, provided that in larger distances from the black hole magnetic diffusivity is dominant, and thus, the magnetic field will never reach equipartition values. For , we show the immediate consequences of this specific magnetic field geometry, which are: (i) an intermittent flow that passes from quiescent states to flaring activity, (ii) no quasi-steady-state jet, (iii) no possibility of a magnetically arrested configuration. Moreover, a further distinctive feature of this geometry is the intense magnetic reconnection events, occurring as layers of opposite magnetic polarity, accreted in the vicinity of the black hole. Finally, we argue that the absence of a jet structure in such case will be a smoking gun in 43 and 86 GHz observations. © 2022 The Author(s)
- …
