Bridge deck aerodynamics: A case study in full-scale

PhD thesis in Mechanical and Structural Engineering and Materials ScienceOne of the key aspects of bridge deck aerodynamics is the transformation of the incident wind flow into fluctuating surface pressures around a bridge deck. The atmospheric turbulence generates fluctuating loads on bridge decks, i.e. the buffeting wind action. The state-of-the-art knowledge about bridge deck aerodynamics, as well as the bases for the design of long-span bridges, relies primarily on wind-tunnel testing. By contrast, full-scale studies concentrating on the surface pressure distributions around bridge girders are rare. The central thrust of this work is to develop an experimental setup to investigate the aerodynamics of a closed-box girder bridge deck in full-scale. A bespoke pressure measuring system is designed and developed to monitor wind-induced surface pressures around three chords of the Lysefjord Bridge in Norway, previously instrumented by a number of wind and vibration sensors. The one- and two-point statistics of the undisturbed turbulence are simultaneously measured, thereby facilitating the study of the spatial structure of the gust loading in the atmosphere. The experimental setup is aided by 3D sonic anemometers placed within the disturbed flow regions, upstream of the bridge deck nose and in the near wake. The overall distortion of the atmospheric turbulence induced by the bridge deck body is examined, as well as the related vortex shedding process. In particular, the flow in the near-wake region of the bridge deck is investigated, in both model- and full-scale. For skewed incident winds, the near-wake flow exhibits highly three-dimensional features, including a significant axial flow on the leeward side of the full-scale bridge deck. Also, the frequency-dependent energy redistribution within the near wake is examined with emphasis on wavelengths associated with the periodic formation of vortex structures. The Strouhal number associated with the deck cross-section studied is found to be similar in both full- and model-scale. The turbulence level in the inflow is found to impact significantly the value of the non-dimensional vortex shedding frequency in full-scale. Specifically, the higher the turbulence intensity, the higher the Strouhal number. Lastly, the “anatomy” of the vortex shedding process is described based on the surface pressure measurements undertaken on the trailing edges of the deck. Investigating the gust loading generation in full-scale is central to this research. Fluctuating drag, lift and twisting moment are estimated on three chord-wise strips, based on a limited number of pressure sensing points. The analysis of the monitored surface pressures underpins the limits of the strip assumption in modelling the correlation along the bridge span of the lift and moment. Specifically, the span-wise coherence of the turbulence-driven lift and moment is observed to be higher than the span-wise coherence of the incident vertical velocity fluctuations. This result, which is deemed original given its full-scale framework, is in an overall agreement with the wind tunnel studies focusing on the gust loading on motionless section models of closedbox girder bridge decks. Also, a pronounced amplification of the vertical velocity fluctuations is observed upstream of the bridge deck nose, thereby providing a link between the undisturbed turbulence and the resulting gust loading on the deck. Keywords: Bridge deck aerodynamics, Full-scale, Wind turbulence, Nearwake flow, Wind buffeting, Surface pressure measurement

Innovative engine configurations and waste heat recovery solutions employed on large cruise ship to meet new environmental regulations

Due to recent regulations imposed by IMO (Int. Maritime Org.), pollution emissions produced by large ships are now under strict control, and a widening part of the seas (called SECA) is now accessible only by ships with a limited SOx and NOx output. To meet the new regulations, ships propelled by HFO burning Internal Combustion Engines (ICEs) can be equipped with abatement devices such as scrubbers and SCR systems. Although the employment of those devices seems to be the route ship-owners will prefer, other methods can be considered such as the use of MGO, a more expensive fuel but with lower sulphur content. The use of MGO allows considering a further and more drastic modification of the power system, namely the use of Gas Turbines (GTs) in place of ICEs. Gas Turbines, despite of being less efficient, are much lighter, more compact, and can easier reach low NOx emissions than ICEs. Even if these aspects are theoretically well known, there are still difficulties in finding studies reporting quantitative analysis (weight, dimensions, fuel consumption) that compare GTs and ICEs power systems employed on board. The present thesis aims at providing these data by analyzing different solutions applied to a real case. Unlike other studies, the work is focused on a cruise ship rather than on a cargo ship, because cruise ship\u2019s operation profile is more variable during the trip. Finally, solutions to minimize the gap of fuel consumption between GTs and ICEs is also discussed

An interoperable ICT tool for asset and maintenance management -Advances in research –

Asset and maintenance management needs to store and use much information about the behaviour over time of different building materials, products and components. Service life planning and data capitalization from facility management are only the first steps for an efficient asset management because it is necessary to develop specific ICT tools for life cycle data use and sharing. Managing information related with actual maintenance works and inspection activity (condition assessment) allow handling Building Information Systems and this is fundamental in order to fit the reliability and service life evaluations for maintenance planning. For this reason, an ongoing research activity is developing some methods and tools for Service Life Planning and Management, which can be easily integrated by maintenance data to be used during planning, design, facility and maintenance activities. The aim is to develop an interoperable Life Cycle Management System (LCMS) platform where this kind of data are available and where different stakeholders can store and share information about building and constructed assets. The interoperable LCMS platform can be then used on actual maintenance works management to demonstrate the benefit as for economic (Life Cycle Costs) and environmental achievements (Life Cycle Assessment). This operation has been done according to the international standard for service life planning of building and constructed asset procedures ISO 15686, in particular in conformity with the fifth part on Life-cycle Costing, which allows a cost analysis of the entire building life cycle (maintenance included). Eventually, this ICT-tool is being developed using the standard IFC (Industrial Foundation Classes) of IAI (International Alliance for Interoperability) to define Building Information Models (BIM). In particular, interoperability will be guarantee by sharing file .ifcxml and therefore using eXtensible Mark-up Language (XML). Service life data, maintenance information, costs and each parameter for sustainability have in fact to be matched with Building Information Models attributes, upgrading BIM objects themselves in case of lack of some attributes. This database will be accessible online from a web platform, which is thought to become an interactive footbridge among different stakeholders. As the quantity of collected information will be huge, there are different views of the database according to the stakeholder profile: the aim is to facilitate its use, filtering only useful data for the considered stakeholder, but leaving the possibility to search, visualize and, possibly, modify any other information of the database. Hereafter the advances in research to structure this database and to enhance existing methods and tools for Life Cycle management are described

Gas Turbines for Power Generation on Board of Cruise Ships: A Possible Solution to Meet the New IMO Regulations?

AbstractIn order to reduce the environmental impact caused by merchant ships, the International Maritimes Organization is imposing new and stricter regulations on NOx and SOx emissions. Therefore, ships propelled by Internal Combustion Engines (ICEs) burning HFO must adopt abatement devices or switch to a cleaner fuel such as MGO. If the use of MGO is considered, a further and more drastic modification of the power system can be analyzed, namely the use of Gas Turbines (GTs) in place of ICEs. GTs are an attractive solution thanks to a reduced weight, size and NOx emissions, but are penalized by a lower electric efficiency. The case of a real cruise ship is considered in the present paper and a detailed quantification of the above mentioned differences is provided by simulating the ship operation for a reference trip

Maximum Entropy Approach for the Prediction of Urban Mobility Patterns

The science of cities is a relatively new and interdisciplinary topic. It borrows techniques from agent-based modeling, stochastic processes, and partial differential equations. However, how the cities rise and fall, how they evolve, and the mechanisms responsible for these phenomena are still open questions. Scientists have only recently started to develop forecasting tools, despite their importance in urban planning, transportation planning, and epidemic spreading modeling. Here, we build a fully interpretable statistical model that, incorporating only the minimum number of constraints, can predict different phenomena arising in the city. Using data on the movements of car-sharing vehicles in different Italian cities, we infer a model using the Maximum Entropy (MaxEnt) principle. With it, we describe the activity in different city zones and apply it to activity forecasting and anomaly detection (e.g., strikes, and bad weather conditions). We compare our method with different models explicitly made for forecasting: SARIMA models and Deep Learning Models. We find that MaxEnt models are highly predictive, outperforming SARIMAs and having similar results as a Neural Network. These results show how relevant statistical inference can be in building a robust and general model describing urban systems phenomena. This article identifies the significant observables for processes happening in the city, with the perspective of a deeper understanding of the fundamental forces driving its dynamics.Comment: 14 pages, 7 figure

Glycosylation of glycolipids in cancer: basis for development of novel therapeutic approaches

Altered networks of gene regulation underlie many pathologies, including cancer. There are several proteins in cancer cells that are turned either on or off, which dramatically alters the metabolism and the overall activity of the cell, with the complex machinery of enzymes involved in the metabolism of glycolipids not being an exception. The aberrant glycosylation of glycolipids on the surface of the majority of cancer cells, associated with increasing evidence about the functional role of these molecules in a number of cellular physiological pathways, has received considerable attention as a convenient immunotherapeutic target for cancer treatment. This has resulted in the development of a substantial number of passive and active immunotherapies, which have shown promising results in clinical trials. More recently, antibodies to glycolipids have also emerged as an attractive tool for the targeted delivery of cytotoxic agents, thereby providing a rationale for future therapeutic interventions in cancer. This review first summarizes the cellular and molecular bases involved in the metabolic pathway and expression of glycolipids, both in normal and tumor cells, paying particular attention to sialosylated glycolipids (gangliosides). The current strategies in the battle against cancer in which glycolipids are key players are then described.Fil: Daniotti, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Vilcaes, Aldo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Torres Demichelis, Vanina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Ruggiero, Fernando Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Rodríguez Walker, Macarena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin

The building materials’ and components’ database for an evidences-based design approach

The design process has always to meet, since the preliminary approaching step, every specific requirement which is foreseen for the building to realize. In a certain way, this operation represents an every time different prototype which varies according to the design demands for the considered room and the carried function, but also according to the used building materials: such an approach is already difficult by itself, but if we consider that at present the availability of technical information about building materials, components and systems is often incomplete or lost among many documents or even absent, it is evident that the designer’s activity becomes very uneven. That is the reason why, the definition of a database for building materials in which indicating each informative attribute to be considered becomes fundamental in order to: - provide a correct, univocal, clear and complete information for every building stakeholder; - help manufacturers to individualize the real needed information to join to their products, so to allow an easier comparison among products themselves and, as a consequence, to push towards a better quality of the entire building process (improving production, design, but also management). The paper deals with an analysis of the necessary information for designers and for maintenance planners, providing different levels of deepening according to the intended use. A particular attention will be paid on the so called “evidences-based design” which gives the opportunity to point out and to consider the most meaningful design matters, making an aware choice of building materials, components and systems. The International Service Life Data Base developed by CSTB with Politecnico di Milano will be reported as a tool for service life prediction, and buildings’ management

AUTOMATED IFC-BASED PROCESSES IN THE CONSTRUCTION SECTOR: A METHOD FOR IMPROVING THE INFORMATION FLOW

One of the main challenges in the implementation of BIM-based processes concerns interoperability issues. In fact, even if IFC format is recognised as an ISO standard, different barriers and problems are often encountered in IFC adoption. Generally, obstacles are due to the difficulty of users in personalising import and export options of IFC formats in BIM authoring tools with the consequent possibility of information loss. The paper presents a method for improving the information flow, based on the connection of information stored in IFC files and in external databases through automated processes. Therefore, information concerning one single project can be stored in BIModels and linked to external sources or, conversely, referred from external databases to objects in BIModels. Benefits deriving from the adoption of the proposed solutions concern the limited size of BIModels, the possibility to store information not considered in the IFC schema, and the reduction of IT skills required to building operators for exchanging information in an interoperable way