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Dry-spell assessment through rainfall downscaling comparing deep-learning algorithms and conventional statistical frameworks

Full title: Dry-spell assessment through rainfall downscaling comparing deep-learning algorithms and conventional statistical frameworks in a data scarce region: The case of Northern Ghana By Panagiotis Mavritsakis Large parts of the world rely on rainfed agriculture for their food security. In Africa, 90% of the agricultural yields rely only on precipitation for irrigation purposes and approximately 80% of the population’s livelihood is highly dependent on its food production. Parts of Ghana are prone to droughts and flood events due to increasing variability of precipitation phenomena. Crop growth is sensitive to the wet- and dry-spell phenomena during the rainy season. To support rural communities and small farmer in their efforts to adapt to climate change and natural variability, it is crucial to have good predictions of rainfall and related dry/wet spell indices. This research constitutes an attempt to assess the dry-spell patterns in the northern region of Ghana, near Burkina Faso. We aim to develop a model which by exploiting satellite products overcomes the poor temporal and spatial coverage of existing ground precipitation measurements. The main objective is to reproduce the dry spell sequences as seen by the rain gauges (point scale) in the region of Northern Ghana based on satellite precipitation products (CMORPH, TAMSAT, IMERG). We will compare conventional statistical tools and Machine Learning classification models and deep-learning algorithms to establish a link between satellite products and field rainfall data for dry-spell assessment. The deep-learning architecture used should be able to process satellite images efficiently. Hence, several Convolutional Neural Network architectures were tested as classifiers. Using these models we will attempt to exploit the long temporal coverage of the satellite products in order to overcome the poor temporal and spatial coverage of existing ground precipitation measurements. Doing that, our final objective is to enhance our knowledge about the dry-spell characteristics and, thus, provide more reliable climatic information to the smallholder farmers in the area of Northern Ghana.

Automatic Extraction of Ridge Structures from Digital Elevation Models for the modelling software D-HYDRO

Automatic Extraction of Ridge Structures from Digital Elevation Models for the modelling software D-HYDRO By Thirza van Noppen with supervisor: Ruud van der Ent In order to avoid substantial damage as a result of flooding and extreme water discharges, it is of considerable importance to model flood events as it can help in flood risk reduction and mitigation. Numerous hydrodynamic simulation models have been designed for the purpose of modelling the movement of water and are widely used to assess flooding risk. The simplest and most common practice in these models is to use one-dimensional (1D) models that treat flow one-dimensionally along the river channel. Alternatively, two-dimensional (2D) models can provide more detailed results but they remain computationally demanding and data intensive. Recent advances and software developments resulted in novel mechanisms that can reduce computation costs. One of these mechanisms is the incorporation of fixed weirs in a hydrodynamic model. Fixed weirs represent abrupt changes in altitude that have an impact on the local flow during flooding. The fixed weirs can be incorporated into modelling software such as 3Di, HEC-RAS and D-HYDRO Suite. The weir elements are aligned on the 2D-grid network, hence the resolution of the model can be kept large while sudden changes in depth are taken into account. Until now, fixed weirs are still drawn manually or with the aid of existing data of roads or railways, which is a labor-intensive and time consuming process. In addition, the process of manually drawing fixed weirs is a subjective process and is therefore largely dependent on the interpretation of the modeler. The main objective of this study is to develop a tool that can automatically detect ridge structures based on a digital elevation model (DEM). Subsequently, the results of the tool will be evaluated in a D-HYDRO model developed for the river Roer (which is located in the province Limburg in The Netherlands). In order to do so, three approaches will be compared: a model with fixed weirs detected by the tool, a model containing no fixed weirs, and one with manually drawn fixed weirs.

Develop a monitoring scheme for the WaterStreet’s living lab

By Alexandra Vyrini, with supervisor Dr.ir. M.M. Rutten Climate and land use change pose a threat to urban environments as they are positively correlated with the increase in extreme phenomena. Sustainable urban drainage systems (SUDS) can provide an alternative way to reduce the discharge of water to the stormwater sewer system by increasing the permeability of the pavement and creating storage underneath. Although these sustainable urban drainage systems sound very promising, they are often facing many obstacles before full-scale implementation. Lack of public awareness and the inertia of system’s change due to governance, regulations and institutional constraints put a brake towards the implementation of innovative solutions. In this regard, WaterStreet (https://thegreenvillage.org/project/waterstraat/) is a living lab that tries to reduce the effect of the factors mentioned before, by demonstrating and testing new solutions towards a sustainable urban stormwater management, without the involvement of the government. The aim of WaterStreet is to make the jump to the market smaller. From a technological perspective the reliability of SUDS’s performance is regarded the most important factor for end users to incorporate them in city planning. Maintenance of the systems, underlying soil type and vegetation are some of the factors that can affect the long-term performance of SUDS. Monitoring can be an important tool to investigate the performance of new SUDS before pilot implementation reducing the uncertainty for end users. It is therefor proposed to develop a monitoring scheme for the WaterStreet’s living lab that will enhance the knowledge on how these systems work in real live situations. A parallel study will be performed in order to include the need of data for simulation purposes. Simulation of those SUDS can be an important tool for city planning further accelerating the possibility of implementation of SUDS.

Develop a monitoring scheme for the WaterStreet’s living lab

By Alexandra Vyrini, with supervisor Dr.ir. M.M. Rutten Climate and land use change pose a threat to urban environments as they are positively correlated with the increase in extreme phenomena. Sustainable urban drainage systems (SUDS) can provide an alternative way to reduce the discharge of water to the stormwater sewer system by increasing the permeability of the pavement and creating storage underneath. Although these sustainable urban drainage systems sound very promising, they are often facing many obstacles before full-scale implementation. Lack of public awareness and the inertia of system’s change due to governance, regulations and institutional constraints put a brake towards the implementation of innovative solutions. In this regard, WaterStreet (https://thegreenvillage.org/project/waterstraat/) is a living lab that tries to reduce the effect of the factors mentioned before, by demonstrating and testing new solutions towards a sustainable urban stormwater management, without the involvement of the government. The aim of WaterStreet is to make the jump to the market smaller. From a technological perspective the reliability of SUDS’s performance is regarded the most important factor for end users to incorporate them in city planning. Maintenance of the systems, underlying soil type and vegetation are some of the factors that can affect the long-term performance of SUDS. Monitoring can be an important tool to investigate the performance of new SUDS before pilot implementation reducing the uncertainty for end users. It is therefor proposed to develop a monitoring scheme for the WaterStreet’s living lab that will enhance the knowledge on how these systems work in real live situations. A parallel study will be performed in order to include the need of data for simulation purposes. Simulation of those SUDS can be an important tool for city planning further accelerating the possibility of implementation of SUDS.

Assess the potential of a weir as mechanism for contributing to a sustainable sand balance on the Volta River

By Jon Arends, with supervisor Prof. dr. ir. Nick Van de Giesen Tamale, a city in the Northern Region of Ghana is rapidly urbanizing resulting in a large demand for residential and commercial construction, roads and infrastructure to meet the needs of the growing population. This infrastructure is primarily composed of concrete, which requires large volumes of sands and aggregates in its production. These sands and aggregates come primarily from two sources: marine and terrestrial. Terrestrial sand is used which is generally sourced from river channels and flood plains. When sand and aggregates are extracted at volumes that far exceed the rate of replenishment, it often causes grave environmental consequences. In Tamale, terrestrial sand is used for concrete works. It is estimated that between 50-65% of sand and aggregates is excavated from the river beds and walls of the Volta River with volumes expected to grow to meet the cities demands. Without proper guidance to maintain a sustainable sand balance, the Tamale region of the Volta River may experience habitat transformation, erosion, channel incision, decreased water supply and increased flood risk. Weirs are being explored to regulate the water supply for the city. Consequently, sand and aggregates will settle upstream of the weir. Can these weirs be used to sustainably remove sand from the Volta River without long term damage? How much sand could safely be removed? Questions like these hope to be answered in this research.

Assess the potential of a weir as mechanism for contributing to a sustainable sand balance on the Volta River

By Jon Arends, with supervisor Prof. dr. ir. Nick Van de Giesen Tamale, a city in the Northern Region of Ghana is rapidly urbanizing resulting in a large demand for residential and commercial construction, roads and infrastructure to meet the needs of the growing population. This infrastructure is primarily composed of concrete, which requires large volumes of sands and aggregates in its production. These sands and aggregates come primarily from two sources: marine and terrestrial. Terrestrial sand is used which is generally sourced from river channels and flood plains. When sand and aggregates are extracted at volumes that far exceed the rate of replenishment, it often causes grave environmental consequences. In Tamale, terrestrial sand is used for concrete works. It is estimated that between 50-65% of sand and aggregates is excavated from the river beds and walls of the Volta River with volumes expected to grow to meet the cities demands. Without proper guidance to maintain a sustainable sand balance, the Tamale region of the Volta River may experience habitat transformation, erosion, channel incision, decreased water supply and increased flood risk. Weirs are being explored to regulate the water supply for the city. Consequently, sand and aggregates will settle upstream of the weir. Can these weirs be used to sustainably remove sand from the Volta River without long term damage? How much sand could safely be removed? Questions like these hope to be answered in this research.

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Students Amos Yusuf, Mick Dam & Bas Brouwer winners of Mekel Prize 2024

Master students Amos Yusuf, from the ME faculty (Mick Dam, from the EEMCS faculty and graduate Bas Brouwer have won the Mekel Prize 2024 for the best extra scientific activity at TU Delft: the development of an initiative that brings master students into the classroom teaching sciences to the younger generations. The prize was ceremonially awarded by prof Tim van den Hagen on 13 November after the Van Hasselt Lecture at the Prinsenhof, Delft. They received a statue of Professor Jan Mekel and 1.500,- to spend on their project. Insights into climate change are being openly doubted. Funding for important educational efforts and research are being withdrawn. Short clips – so called “reels” – on Youtube and TikTok threaten to simplify complex political and social problems. AI fakes befuddle what is true and what is not. The voices of science that contribute to those discussion with modesty, careful argument and scepticism, are drowned in noise. This poses a threat for universities like TU Delft, who strive to increase student numbers, who benefit from diverse student populations and aim to pass on their knowledge and scientific virtues to the next generation. It is, therefore, alarming that student enrolments to Bachelor and Master Programs at TU Delft have declined in the past year. Students in front of the class The project is aimed to make the sciences more appealing to the next generation. They have identified the problem that students tend miss out on the opportunity of entering a higher education trajectory in the Beta sciences – because they have a wrong picture of such education. In their mind, they depict it as boring and dry. In his pilot lecture at the Stanislas VMBO in Delft, Amos Yusuf has successfully challenged this image. He shared his enthusiasm for the field of robotics and presented himself as a positive role model to the pupils. And in return the excitement of the high school students is palpable in the videos and pictures from the day. The spark of science fills their eyes. Bas Brouwer Mick Dam are the founders of NUVO – the platform that facilitates the engagement of Master Students in high school education in Delft Their efforts offer TU Delft Master Students a valuable learning moment: By sharing insights from their fields with pupils at high school in an educational setting, our students can find identify their own misunderstandings of their subject, learn to speak in front of non-scientific audiences and peak into education as a work field they themselves might not have considered. An extraordinary commitment According to the Mekel jury, the project scored well on all the criteria (risk mitigation, inclusiveness, transparency and societal relevance). However, it was the extraordinary commitment of Amos who was fully immersed during his Master Project and the efforts of Brouwer and Dam that brought together teaching and research which is integral to academic culture that made the project stand out. About the Mekel Prize The Mekel Prize will be awarded to the most socially responsible research project or extra-scientific activity (e.g. founding of an NGO or organization, an initiative or realization of an event or other impactful project) by an employee or group of employees of TU Delft – projects that showcase in an outstanding fashion that they have been committed from the beginning to relevant moral and societal values and have been aware of and tried to mitigate as much as possible in innovative ways the risks involved in their research. The award recognizes such efforts and wants to encourage the responsible development of science and technology at TU Delft in the future. For furthermore information About the project: https://www.de-nuvo.nl/video-robotica-pilot/ About the Mekel Prize: https://www.tudelft.nl/en/tpm/our-faculty/departments/values-technology-and-innovation/sections/ethics-philosophy-of-technology/mekel-prize

New catheter technology promises safer and more efficient treatment of blood vessels

Each year, more than 200 million catheters are used worldwide to treat vascular diseases, including heart disease and artery stenosis. When navigating into blood vessels, friction between the catheter and the vessel wall can cause major complications. With a new innovative catheter technology, Mostafa Atalla and colleagues can change the friction from having grip to completely slippery with the flick of a switch. Their design improves the safety and efficiency of endovascular procedures. The findings have been published in IEEE. Catheter with variable friction The prototype of the new catheter features advanced friction control modules to precisely control the friction between the catheter and the vessel wall. The friction is modulated via ultrasonic vibrations, which overpressure the thin fluid layer. This innovative variable friction technology makes it possible to switch between low friction for smooth navigation through the vessel and high friction for optimal stability during the procedure. In a proof-of-concept, Atalla and his team show that the prototype significantly reduces friction, averaging 60% on rigid surfaces and 11% on soft surfaces. Experiments on animal aortic tissue confirm the promising results of this technology and its potential for medical applications. Fully assembled catheters The researchers tested the prototype during friction experiments on different tissue types. They are also investigating how the technology can be applied to other procedures, such as bowel interventions. More information Publicatie DOI : 10.1109/TMRB.2024.3464672 Toward Variable-Friction Catheters Using Ultrasonic Lubrication | IEEE Journals & Magazine | IEEE Xplore Mostafa Atalla: m.a.a.atalla@tudelft.nl Aimee Sakes: a.sakes@tudelft.nl Michaël Wiertlewski: m.wiertlewski@tudelft.nl Would you like to know more and/or attend a demonstration of the prototype please contact me: Fien Bosman, press officer Health TU Delft: f.j.bosman@tudelft.nl/ 0624953733

A key solution to grid congestion

On behalf of the TU Delft PowerWeb Institute, researchers Kenneth Brunninx and Simon Tindemans are handing over a Position Paper to the Dutch Parliament on 14 November 2024, with a possible solution to the major grid capacity problems that are increasingly cropping up in the Netherlands. The Netherlands is unlikely to meet the 2030 climate targets, and one of the reasons for this is that large industry cannot switch to electricity fast enough, partly because of increasingly frequent problems around grid capacity and grid congestion. In all likelihood, those problems will actually increase this decade before they can decrease, the researchers argue. The solution offered by the TU Delft PowerWeb Institute researchers is the ‘flexible backstop’. With a flexible backstop, the current capacity of the power grid can be used more efficiently without sacrificing safety or reliability. A flexible backstop is a safety mechanism that automatically and quickly reduces the amount of electricity that an electric unit can draw from the grid (an electric charging station or a heat pump) or deliver (a PV installation). It is a small device connected or built into an electrical unit, such as a charging station or heat pump, that ‘communicates’ with the distribution network operator. In case of extreme stress on the network, the network operator sends a signal to the device to limit the amount of power. Germany recently introduced a similar system with electric charging stations. The backstop would be activated only in periods of acute congestion problems and could help prevent the last resort measure, which is cutting off electricity to users. ‘Upgrading the electricity network remains essential, but in practice it will take years. So there is a need for short-term solutions that can be integrated into long-term planning. We, the members of the TU Delft PowerWeb Institute, call on the government, network operators and regulator to explore the flexible backstop as an additional grid security measure,’ they said. The entire Paper can be read here . Kenneth Brunninx Associate Professor at the Faculty of Engineering, Governance and Management, where he uses quantitative models to evaluate energy policy and market design with the aim of reducing CO2 emissions. Simon Tindemans is Associate Professor in the Intelligent Electrical Power Grids group at Faculty of Electrical Engineering, Mathematics and Computer Science. His research interests include uncertainty and risk management for power grids. TU Delft PowerWeb Institute is a community of researchers who are investigating how to make renewable energy systems reliable, future proof and accessible to everyone.

25 year celebration of formal collaboration between Delft University of Technology and the University of Campinas

On 25 October 2024 we celebrated 25 years of formal collaboration between Delft University of Technology and the University of Campinas. What began as a project to exchange some students in chemical engineering has now grown to a multifaceted and broad academic collaboration which accumulated into 24 joint research projects (>20 M Euro); 16 advanced courses and 15 Doctors with a Dual Degree PhD. Patricia Osseweijer, TU Delft Ambassador Brazil explained, “We are proud to show and reflect on this special day the added value we created resulting from our joint activities. The lessons we learned demonstrate that especially continuity of funds and availability for exchanges has contributed to joint motivation and building trust which created strong relations. This is the foundation for academic creativity and high-level achievements.” The program presented showcases of Dual Degree projects; research activities and education. It discussed the future objectives and new fields of attention and agree on the next steps to maintain and strengthen the foundation of strong relations. Telma Franco, Professor UNICAMP shared that “joint education and research has substantially benefitted the students, we see that back in the jobs they landed in,” while UNICAMP’s Professor Gustavo Paim Valenca confirmed that “we are keen to extend our collaboration to more engineering disciplines to contribute jointly to global challenges” Luuk van der Wielen highlighted that “UNICAMP and TU Delft provide valuable complementary expertise as well as infrastructures to accelerate research and innovation. Especially our joint efforts in public private partnerships brings great assets” To ensure our future activities both University Boards have launched a unique joint program for international academic leadership. This unique 7-month program will accommodate 12 young professors, 6 from each university. The programme began on 4 November 2024 in Delft, The Netherlands.