Speaker	Dimitrios Razis (CV) Post-Doctoral Researcher, Department of Civil Engineering
Topic	Nonlinear Waves in Open Channel Flow: A Dynamical Systems Approach (brochure)
Date	30/11/2022, 11:15 (video (DIAVLOS, YouTube))
Abstract	Monoclinal Flood Waves, Undular Bores, Roll Waves and Solitons are among the most iconic travelling wavefoms observed in Open Channel Flow. On the other side of the spectrum, the Hydraulic Jump, often encountered in open channels, constitutes a paradigmatic example of a standing waveform. In this lecture we will show how the generalized Saint‒Venant Equations ―governing shallow water flow― reduce to a 2nd order nonlinear Ordinary Differential Equation (ODE) capturing the shape of all standing and travelling waveforms appearing in Open Channel Flow. To analyze the aforementioned 2nd order ODE we adopt a Dynamical Systems approach, i.e. we treat it as a set of two coupled 1st order ODEs. From this perspective, all travelling waveforms manifest themselves as bounded trajectories in the phase space (local slope vs. local flow depth of a wave) of the dynamical system. The Dynamical Systems approach provides an unprecidented, tangible geometrical insight on the structure of the various waveforms in Open Channel Flow.

Speaker	Ioannis Kakaras (CV) Professor Emeritus, Department of Forestry, Wood Sciences & Design
Topic	Wood products as building materials (brochure)
Date	7/12/2022, 11:15 (video (DIAVLOS, YouTube))
Abstract	A brief holistic approach of the application of wood building materials in Greece is presented using the appropriate wood species and wooden products. An examination of the wood building constructions is presented, and material failures are highlighted. Techniques and rules of applications which ensure the quality and long lifespan of the wood building constructions are suggested. The rules for the combined use of wood building materials with other building materials as concrete, metals, aluminum and glass are presented. The basic wood structure failures that must be avoided are presented, as well as methods and techniques for the efficient control of errors that can be handled. Simple techniques and methods are suggested for the initial prevention or in situ conservation of wood building contractions, such as roofs, windows, doors, outdoor constructions exposed to the rain, humidity, extreme temperatures and/or in contact with the water or the ground. The necessity for correct specialization of all the participants that are involved in the design or production of wooden building constructions (civil engineers, architects, wood technologists, technicians, wood product merchants) in Greece is emphasized.

Speaker	Anastasia Angelaki (CV) Instructor, Department of Agriculture Crop Production and Rural Environment
Topic	Estimation of hydraulic parameters using laboratory experiments and simulation models (brochure)
Date	11/1/2023, 11:15 (video (DIAVLOS, YouTube))
Abstract	Series of laboratory experiments and mathematical modeling that led to estimation of crucial hydraulic parameters which play significant role to water motion into different soil types are going to be presented. Firstly, experiments were carried out, in order to obtain the particle size distribution of the porous media, while basic hydraulic parameters were determined, such as saturated hydraulic conductivity, soil moisture at saturation, etc. Subsequently, two circles of experiments were carried out: During the first circle, the incoming water volumes were measured, while at the same time, soil moisture at various depths was recorded via electromagnetic waves (TDR). Cumulative infiltration curves and soil moisture profiles were extracted and comparison of the infiltrated water volumes with the volumes that came out from the integration of the moisture profiles was derived. At the second experimental circle, soil moisture along with soil pore pressure was measured and recorded using a ceramic capsule-pressure transducer system, during drainage and imbibition processes. Comparative evaluation of two infiltration models was held using the experimental data, while the effect of the hydraulic parameters on water motion was investigated. Also, the characteristic curves of the 1st drainage, the 2nd imbibition and the 2nd drainage were extracted and the not-injective relationship of soil moisture-pressure was confirmed. Specific software was used to simulate the imbibition process and the hydraulic parameters that affect the shape and form of the characteristic curve were derived. In addition, hydraulic capacity (C), diffusivity (D), unsaturated hydraulic conductivity (K) and sorptivity (S) were also determined using algebraic, numerical and graphical methods. Theoretical research on the mathematical models that were used, along with the correlation of the experimental results with the predictions of the theoretical research was also carried out. Finally, the results of a recent research (2022) will be presented, where the above methods have been extended to soils contaminated with heavy metals, in order to investigate the impact of the presence of the heavy metal cations on hydraulic parameters and water motion.

Speaker	George Mantanis (CV) Professor, Department of Forestry, Wood Sciences & Design - Laboratory of Wood Science & Technology
Topic	Traditional and modern techniques for wood protection (brochure)
Date	15/3/2023, 11:15 (video (DIAVLOS, YouTube))
Abstract	The lecture is related to the traditional and modern techniques used in the protection of wood. In the beginning, fundamentals respecting the wood as a biological material, its main disadvantages, and the main biotic and abiotic factors deteriorating the wood, are discussed. Then, the speaker analyses the biological durability of wood and the subsequent use-classes, in accordance with the European standard EN 350. He attempts to present a review of the wooden structures as used in the past, as well as to analyse the traditional techniques for wood protection and conservation relating to pine tar, natural oils and resins. Also, the method of wood protection through impregnation under high pressure, is described and several technical and non- technical aspects of it are discussed. Finally, the old traditional Japanese protection technique called Yakisugi is shortly presented.

Speaker	Hariklia Tsalapatas (CV) Instructor, Department of Electrical and Computer Engineering
Topic	Design Thinking in Engineering Education (brochure)
Date	3/5/2023, 12:00 (video (DIAVLOS, YouTube))
Abstract	Engineering innovation is a driver of growth and well-being today and in the future. By considering feasibility, desirability, and emerging technology it enables the introduction of solutions to business and societal issues of the 21st century, such as climate change, clean and affordable energy, health for all, quality education, poverty mitigation, responsible management of natural resources, and more to drive future growth. Given that today’s students are the problem solvers of tomorrow, who will be challenged to design responses to emerging challenges, higher education as a sector has a responsibility of building student innovation capacity for turning ideas into action. This work presents a gamified design thinking learning intervention for promoting the development of innovation competences among engineering students for introducing solutions to difficult challenges, even if none appears to exist at first glance. Design thinking achieves this through a process of problem-discovery that allows designers to put themselves in the position of users either literally, by immersing themselves in the users’ environment, or through an engagement process that helps them better understand actual, as opposed to perceived, needs. The process allows for the definition of a more accurate problem statement, which in turn may allow the design more effective solutions. Design thinking encourages brainstorming for introducing a broad toolset of potential solutions, from which the design team selects the most viable for developing and evaluating prototypes by further engaging users. A digital collaboration service has been developed that encourages students to engage in problem-solving in teams anywhere and anytime. Through the learning service under development students work in jointly owned digital workspaces in which they may share their work on problem discovery and understanding, analysis of user needs, problem definition, and solution design. The proposed service is flexible and encourages students to share and build on each other’s ideas through small notes posted on a common canvas. The educator has broad flexibility in designing exercises for engaging students as well as in highlighting specific steps of the design thinking process. Finally, gamification elements, such as clear goals, feedback, recognition, rewards, and a sense of affiliation, promote student long-term engagement in the learning process. The work is implemented in project ICT-INOV: Modernizing ICT Higher Education for Harvesting Innovation that is funded by the Erasmus+ Capacity Building in Higher Education program. It is implemented in Greece, Portugal, Italy, Estonia, Malaysia, Vietnam, Pakistan, and Nepal encouraging the exchange of know-how and experiences towards modernizing higher education practices.

Speaker	Nikolaos Maniotis (CV) Post-Doctoral Researcher (AUTH), Academic fellow (UTH)
Topic	Computational study of separation of magnetic nanoparticles from fluids in biomedical and environmental applications (brochure)
Date	12/5/2023, 14:00 (video (DIAVLOS, YouTube))
Abstract	The process of migration of magnetic nanoparticles and colloids in solution under the influence of magnetic field gradients is an essential step in separation technology used in various biomedical applications. In addition, several environmental applications of magnetic nanoparticles have already been implemented on a large scale, such as wastewater treatment and pollutant removal. In some of these applications, magnetic nanoparticles are added to circulating water to purify it from toxic substances such as hexavalent chromium. The first objective of this lecture is to approach the artificial removal of magnetic nanoparticles from the blood circulation under the influence of an external magnetic field, through a mathematical model corresponding to the model of targeted drug delivery and to determine the conditions under which their separation becomes possible. The second objective is to study the removal of magnetic nanoparticles from drinking water with the further development of a pilot device. This consists of a rotating disc on which rectangular NdFeB permanent magnets are hosted in a Halbach arrangement (Figure). In both cases presented, the study is done computationally in two and three dimensions by numerically solving the differential equations and simulating the trajectories of the particles, for different combinations of values of the parameters that affect the movement, estimating each time the percentage of the particles that are being removed by the magnetic field, with the aim of identifying the optimal conditions for their complete elimination.