Scheduled Invited Lectures +
Speaker Stavroula Kontoe (CV)
Reader, Imperial College London
Topic Pile design for the foundation of offshore wind turbines in challenging ground conditions (brochure) Date 26/5/2021, 12:00 (webinar (MS Teams), live streaming (DIAVLOS, YouTube)) Abstract The current worldwide drive towards renewable, low carbon energy has led to rapid expansion in the offshore wind energy sector, moving to deeper waters and larger turbines. The foundations of offshore wind turbines consume a substantial proportion of the capital cost and are designed to sustain axial and lateral loading under both monotonic and cyclic conditions, due to the wind and wave action. Existing design procedures are well developed for common ground conditions, involving sands and clays, but are lacking behind when encountering other challenging geomaterials. Chalk in particular, a weak, carbonate rock with distinctly brittle behaviour, is widespread in Northern Europe, posing severe challenges for the design of driven piles. The presentation will give an overview of advances that have been made in the design of piles driven in chalk, through a series of research projects at Imperial College involving laboratory and field testing as well as numerical analysis.
Speaker Dr. Maria Tsami
Post-doctoral Research Associate at the Hellenic Institute of Transport (HIT) - Centre for Research and Technology Hellas (CERTH)
Head of the Laboratory D1: Intelligent and personalized algorithms for combined transport and tourism services.
Topic Modeling the impact of transit quality of service on user mode and route choices (brochure) Date 2/6/2021, 12:00 (webinar (MS Teams), live streaming (DIAVLOS, YouTube)) Abstract The lecture focuses on the Transit Quality of Service both in terms of evaluating existing services and in terms of planning and predicting the impact of service quality on user’s decisions regarding mode and route choices. Taking into account the perceptions and expectations of both transit passengers and service operators, a) the service quality GAPs are being identified, b) the key quality of service parameters that are of high importance for service users are being analyzed, c) the relationship between users’ satisfaction from the performed quality with their intentions to use the services is examined and finally d) the impact of transit quality of service on user mode and route choices is underlined. Users’ behavior is being modeled by examining a number of quality scenarios, leading to a model that predicts user’s decisions that able to dynamically predict, wherever these quality conditions apply, decisions and transit assignment. This model acts as a reliable tool for predicting transit assignment under given quality conditions but also for managing quality and information to increase the level of satisfaction of existing and potential travelers in order to attract more users in the service.
2020 - 2021 +
Speaker Hariklia Tsalapatas
Instructor, Department of Electrical and Computer Engineering, University of Thessaly
Topic Problem-based learning in engineering education: experiences in Europe and Asia (brochure) Date 21/10/2020, 13:00 (video) Abstract Capacity Building in Higher Education project ALIEN: Active Learning in Engineering Education (projectalien.eu) aims at promoting active and problem-centred learning as strategic educational approaches in engineering education.
The advantages of active and problem-centred learning are many. They facilitate the development of fundamental knowledge as well as soft skills, such as analytical and critical thinking, entrepreneurial mindsets, the ability to collaborate in interdisciplinary groups, and much more. They prepare students for their transition from the academic environment to the world of work and build their ability to transfer knowledge to professional environments through non-trivial, open-ended learning scenarios inspired by real-life. And they are in line with the ET2020 targets for modernising education through emerging pedagogical design and digital technology.
Despite clear educational advantages, active and problem-based learning are not widely implemented. Reasons that inhibit their widespread development include inadequate physical infrastructures, the lack of open educational digital applications and simulations for supporting active learning, and the need to build trainer capacity on integrating digitally enabled, innovative learning design.
Project ALIEN aims at addressing these challenges by introducing a holistic learning intervention that promotes the broad adoption of active and problem-based learning in Europe and Asia. The project has developed problem-based learning laboratories at 12 universities in Malaysia, Vietnam, Nepal, Pakistan, and Cambodia. It has further developed a digital collaboration platform that acts as a repository of good practices while promoting reuse of educational content towards building value-added learning activities tailored to diverse educational needs. Finally, the project builds the capacity of instructors on deploying active learning through community building events and training that foster the exchange of positive experiences related to problem-based learning in engineering education.
Webinar participants will have the opportunity to deepen their understanding on the benefits of active and problem-based learning, experience the ALIEN learning intervention, and discuss its impact towards building the problem-solvers of tomorrow.
Speaker Yannis N. Krestenitis
Professor, Aristotle University of Thessaloniki
Topic Sea-level changes & coastal floods. Sort-time forecasts. Climatic changes (brochure) Date 4/11/2020, 13:00 (video) Abstract The presentation focuses on coastal floods and inundations of coastal zones, as a result of rising sea levels due to the combined action of astronomical tide, meteorological tide and the action of waves. The operational process of short-term prediction of the phenomena of the total rise of the sea level is presented, with the combined use of meteorological and oceanographic mathematical models. The operational forecast concerns the Mediterranean, the Aegean and the Thermaikos Gulf. The aim is to forecast floods in low-lying coastal areas.
Also presented is the study of the evolution of meteorological tide phenomena (storm surge) for the next hundred years, with the combined use of climate and oceanographic models, considering forecasts (scenarios) of climate change, with reference to the Mediterranean and the Aegean.
Speaker Haris Stamatopoulos
Associate Professor, Norwegian University of Science and Technology, Trondheim, Norway
Topic Timber Buildings: Modeling, Design and Challenges (brochure) Date 11/11/2020, 13:00 (video) Abstract This lecture presents modeling and design aspects of timber buildings. The most common engineering wood products and timber structural systems are briefly presented. The main ultimate limit state (ULS) and serviceability limit state (SLS) design checks according to Eurocode 5 (EN1995-1-1) and other standards are briefly discussed. Some critical issues with respect to modeling of timber structures are presented with focus on modeling of connections. Then, the lecture presents some of the main challenges of the design of tall timber buildings (wind-induced acceleration and deformation and human-induced vibration of floors at the SLS and seismic design timber buildings). Finally, two research projects at NTNU related to the design of tall timber buildings are briefly presented. The WOODSOL project which aims in the development of multi-storey timber buildings with innovative semi-rigid moment-resisting connections; and the DynaTTB project which aims in the determination of the properties (damping and stiffness) of timber buildings subjected to dynamic loading, by use of component tests and forced vibration of buildings with horizontal shakers.
Speaker Nikolaos Mellios
Topic Environmental informatics for modelling of freshwater ecosystems: dynamics and impacts of eutrophication and sustainable agricultural water use (brochure) Date 18/11/2020, 13:00 (video) Abstract The potential of ecological modelling under the frame of environmental informatics to define the factors that affect water quality and quantity parameters on lake ecosystems, will be presented. Karla Reservoir, a Greek hypertrophic constructed lake, suffers from continuous water degradation because of excessive nutrients loading, unaccomplished works, and operational malfunctions. Ecological modelling is conducted to simulate in-lake nutrient dynamics and to reveal the factors affecting its trophic state, while several operational scenarios and a climatic one is applied to estimate the fate of the lake under these hypothetical circumstances. Moreover, cyanotoxins (microcystins) are being modelled through a current artificially intelligence algorithm (ANFIS). Next, cyanobacteria biomass and recreational health risk levels associated to cyanobacterial abundance are modelled on a network of Northern European lakes. Stepwise linear regression, a series of machine learning algorithms and Bayesian hierarchical modelling are applied to test their efficiency in producing reliable results. Lastly, an analysis in terms of which types of crops export the most virtual water through trade, in relation to the benefit in Greek economy, is conducted.
Speaker Marios Anagnostou
Topic Methods and State-of-the-art technologies on the hydrometeorological extremes observations and forecasting: The flash-flood case of Mandra, Attikis (brochure) Date 25/11/2020, 13:00 (video) Abstract Severe hydrometeorological hazards such as floods, droughts, and thunderstorms are expected to increase in the future due to climate change. Due to the significant impacts of these phenomena, it is essential to develop new and advanced early warning systems for advance preparation of the population and local authorities (civil protection, government agencies, etc.). In very short time-periods (up to 6 h), small-scale phenomena can be described accurately by adopting a “nowcasting” approach, providing reliable short-term forecasts and warnings. To this end, a novel nowcasting system is presented in this study, combining a data assimilation system (LAPS), a large amount of observed data, including X- band dual-polarization (XPOL) radar precipitation measurements, the Chemical Hydrological Atmospheric Ocean wave System (CHAOS), and the WRF-Hydro model. The system is evaluated on a case study of the catastrophic flash flood event that occurred in the sub-urban area of Mandra in Western Attica, Greece, on 15 November 2017. The update of the simulations with assimilated radar data improved the initial precipitation description and led to an improved simulation of the evolution of the phenomenon. Comparison with flood data from the FloodHub Service showed that the nowcasting system could have provided reliable early warning of the flood event at least 1 hour in advance, giving vital time to the local authorities to mobilize and even prevent fatalities and injuries to the local population.
Speaker Panos Gourgiotis
Topic Applications of generalized continua to materials with microstructure (brochure) Date 2/12/2020, 13:00 (video) Abstract It is well known that classical continuum theories possess no intrinsic length scale and thus fail to predict the scale effects experimentally observed in problems with geometric lengths comparable to the lengths of the material microstructure. On the other hand, generalized continuum theories intend to capture effects of microstructure by enriching the classical continuum with additional material characteristic length scales, and, thus, extending the range of applicability of the ’continuum’ concept in an effort to bridge the gap between classical continuum theories and atomic-lattice theories. The significance of these theories is that they enrich the classical continuum with additional material characteristic length scales in order to describe the scale effects that emerge from the underlying microstructure. In this way, size effects can be incorporated in the stress analysis in a manner that classical theories cannot afford.
In this presentation, the theory of couple-stress elasticity will be examined starting from first principles. The theory of couple stress elasticity is the simplest gradient type generalized continuum theory that extends the applicability of the classical theory of elasticity and has been extensively used in the last decade to predict the experimentally observed size effects in many stress concentration problems for microstrucrured materials. Here, we will employ the couple-stress theory to examine crack propagation problems in materials with microstructrure and explain the strengthening effects that are observed in fracture of ceramics. Moreover, we will examine instability problems such as folding and stress channelling that can been explained as a failure of ellipticity in a Cosserat material, in a manner similar to that of the formation of shear bands in a plastic material.
Speaker Dimitris Kofinas (CV)
Topic Advanced tools for urban water demand simulation and forecasting at multiple spatio-temporal scales (brochure) Date 9/12/2020, 13:00 (video) Abstract At the current lecture, an investigation on the modeling potential of variable components of the WDNs from the drilling to the tap will be presented. Towards this end, a number of traditional statistical methods will be presented, as well as some AI and hybrid approaches. A number of innovative tools built for specific purposes will also be presented. Among the multiple objectives, on high level, the overall objective is to develop an innovative methodological framework on improving urban water management based on simulation tools that provide detailed overview of the system on multiple scales. The presented investigation is implemented and validated on an actual case study, the WDS of Skiathos Island. This offers some specifications that led to interesting results. Skiathos is a touristic resort with intense touristic influx and intense weather seasonality according to the Mediterranean profile. A series of KPIs has also been applied or introduced and visualised spatio-temporally to reveal hidden cause-effect relations.
Speaker Georgios Tziatzios (CV)
Topic Assessment and prediction of climate change impact on groundwater resources (brochure) Date 16/12/2020, 13:00 (video) Abstract This research aims to assess the quantity and evaluate the quality of the Karla basin groundwater system that is under heavy pressure from both extensive exploitation of the available groundwater resources as well as application of agro-chemical products.
The groundwater status investigation consists of a mathematical simulation of the groundwater flow as well as the transport of nitrates in the lake Karla aquifer using different management scenarios. The Modflow code is used to simulate the subsurface flow and the MT3DMS code for the simulation of groundwater contamination, both codes are part of the Groundwater Modeling System (GMS) suite. Groundwater nitrate pollution is examined at the municipal districts level. The nitrate loading, which varies seasonally, was applied for each type of crop and nitrate leaching was calculated for each crop utilizing the agronomic model GIS-based Environmental Policy Integrated Climate model (GEPIC). Finally, climate change impact on groundwater system is analyzed through SRES scenarios.
Speaker Konstantinos Papoutsis (CV)
Logistics Manager - Sustainability, Nike EMEA Operations
Topic Retail Logistics Costs and Policy Impact: What is the Total Cost to Secure Innovation for a Greener Retail Supply Chain? (brochure) Date 3/3/2021, 12:00 (video) Abstract Public-policies on freight mobility record tangible cost impacts on supply chains and in logistics processes such as goods handling, transportation, etc. Especially for the retail sector which requires a more responsive performance, the effects are even more critical. Thus, society is impacted by air pollution, noise nuisance, etc. for which they are not accountable, and decision-makers are trying to tackle via new policies. Therefore, sustainability has a cost that should be paid by polluters. On the contrary, retailers seek for innovation to offset the additional operational implications. A holistic approach on pinpointing and estimating the total costs that retailers pay in order to ship their products to customers embedding the policy adoption cost is the main scope of the presentation. A cost model of a retail supply chain is built focusing on urban context and the effects of policies and innovations on total costs and sustainability performance of a retailer’s B2B supply chain are estimated. External costs constitute integral part of sustainability and thus, a sustainability analysis is performed between scenarios, encompassing service and social perspectives.
Speaker Leonidas Alexandros Kouris (CV)
Dr Civil Engineer, Joint Research Centre, European Commission
Topic Seismic and energy upgrading of unreinforced masonry buildings (brochure) Date 10/3/2021, 12:00 (video) Abstract There is an always more demanding need to upgrade the existing unreinforced masonry (URM) buildings due to their poor seismic performance during earthquakes which has resulted in severe human and economic losses and their low energy performance which significantly increases their energy consumption. The issue of upgrading the URM buildings is of great priority for EE since they are unengineered vernacular structures and far from the levels of the current standards for seismic capacity and energy consumption. Moreover, the latter combined with deterioration due to ageing of materials, environmental degradation, experience of several earthquakes and lack of maintenance, yield to an even higher vulnerability and energy deficiency. Every recent moderate to high seismic shaking caused damage ranging from cracks to partial or total collapse with a high death toll and economic loss. Therefore, innovative techniques integrating advanced materials for the simultaneous seismic and energy retrofitting of the masonry building stock this should be develop. In masonry buildings there are some more requirements for the targets of the retrofitting related to their traditional nature apart from the structural and energy performance; these can be summarised in the reversibility and compatibility of the strengthening materials. Moreover, cost effectiveness remains an important aspect which should be added to them. SPEctRUM, an EU funded by Marie Skłodowska-Curie Actions project hosted in JRC (EC), proposed a hybrid structural-plus-energy retrofitting solution which combines inorganic textile-based composites with thermal insulation systems for masonry building envelopes to meet all the aforementioned requirements. The use of natural material including lime mortars and natural fibers has been investigated and it has been shown that the capacity can be increased substantially. The cost efficiency of the proposed retrofitting system has been explored in a large-scale EU investigation and short payoff times have been found especially in regions of moderate to high seismicity.
Speaker George Mantanis
Professor, Department of Forestry, Wood Sciences and Design Laboratory of Wood Science & Technology, University of Thessaly
Topic Wood and wooden structures (brochure) Date 31/3/2021, 12:00 (video (DIAVLOS, YouTube)) Abstract This lecture is related mainly to wood as a construction material, and to wooden structures. The lecturer, following a short introduction, attempts to cover both the general and specific fundamental principles in regard to this natural lignocellulosic material, which should be well understood by the new engineer – designer – project manager, so as to effectively utilise wood materials in several applications and constructions. The physical, macroscopic, as well as the microscopic characteristics of wood will be analysed. In addition, technical terms respecting the wooden structures will be given in detail, in correlation with the effect of hazard level in constructions, both in wooden and mixed ones. In that respect, the junior engineer will be informed about the natural durability of the most important timber species, and also, the relevant Use-classes will be briefly discussed. All these are directly related with the European standard ΕΝ 350. Further, some technical details of the European standard EN 338 -which is in conjunction with the mechanical properties of woods- will be presented. Last, few of the typical conservation techniques used in wooden structures, will be briefly displayed.
Speaker Olympia Panagouli
Topic Three-dimensional dynamic response of classical columns consisted of drums connected by dowels (brochure) Date 21/4/2021, 12:00 (video (DIAVLOS, YouTube)) Abstract A numerical investigation on the dynamic response of multi-drum classical columns will be presented. The motivation for this study originates from the need to understand how the 3D dynamic behavior of these columns, surviving in most cases in the form of free-standing columns, is affected by a connection system that was implemented during their construction. For that, the complex dynamic response of multi-drum columns which are part of the colonnade system of the ancient Messene Gymnasium in Greece, is simulated numerically with the finite element code MSC-MARC. In the 3D models, which are based on archaeological information data, special attention is given to the modeling of the iron dowels which were used to connect adjacent drums. The columns are subjected to harmonic ground motions having different acceleration amplitudes and different frequencies. The aim of this parametric study is to investigate the response of the selected columns in both cases, with and without the iron dowels, to understand their role in the overall stability of the column.
Speaker Ioannis Karmpadakis
Lecturer, Imperial College London
Topic Ocean2Coast: Advancements in the statistical representation of waves in the coastal zone (brochure) Date 12/5/2021, 12:00 (video (DIAVLOS, YouTube)) Abstract Hurricanes Rita and Katrina destroyed 113 offshore platforms, 87 of which were in water depths less than 60 m. In this talk, Dr. Karmpadakis will present new physical understanding of the extreme shallow-water waves responsible. This is combined with analyses of an extensive field database and a large set of long, random experimental wave simulations. Key results include an improved description of the largest waves for engineering design and the development of new probabilistic models for extreme waves. In developing these, new light is shed on the competing effects of wave breaking and nonlinear changes. Key aspects of this study have been introduced in the state-of-the-art design of marine and coastal installations, such as offshore wind farms; the reliability assessment of offshore oil and gas platforms; and the improved estimation of coastal flooding.