Person | TU Delft Repository

Marin van Regteren

View Pure Profile

Authored

2 records found

Beneficial use of dredged sediment to enhance salt marsh development by applying a ‘Mud Motor’

Evaluation based on monitoring

Report - Martin Baptist, Julia Vroom, Pim W.J.M. Willemsen, Pim W.J.M. Willemsen, Pim W.J.M. Willemsen, M.E.B. van Puijenbroek, Bas van Maren, Pim van Steijn, Marin van Regteren, I. Colosimo

Bij de haven van Harlingen is een innovatieve methode beproefd voor hergebruik van baggerslib om de ontwikkeling van een kwelder te stimuleren: de slibmotor. Bij een slibmotor wordt baggerspecie als een semi-continue bron van sediment zo dicht mogelijk bij een kwelder verspreid o ...

Limited seed retention during winter inhibits vegetation establishment in spring, affecting lateral marsh expansion capacity

Journal article - Marin van Regteren, I. Colosimo, Pepijn de Vries, M.E.B. van Puijenbroek, Victor Sebastiaan Freij, Martin Baptist, Kelly Elschot

Coastal systems worldwide deliver vital ecosystem services, such as biodiversity, carbon sequestration, and coastal protection. Effectivity of these ecosystem services increases when vegetation is present. Understanding the mechanisms behind vegetation establishment in bio-geomorphic systems is necessary to understand their ability to recover after erosive events and potential adaptations to climate change. In this study, we examined how seed availability affects vegetation establishment in the salt marsh–intertidal flat transition zone: the area with capacity for lateral marsh expansion. This requires vegetation establishment; therefore, seed availability is essential. In a 6-month field experiment, we simulated a before and after winter seed dispersal at two locations, the salt-marsh vegetation edge and the intertidal flat, and studied seed retention, the seed bank, and the seed viability of three pioneer marsh species: Salicornia procumbens, Aster tripolium, and Spartina anglica. During winter storm conditions, all supplied seeds eroded away with the sediment surface layer. After winter, supplied seeds from all three species were retained, mostly at the surface while 9% was bioturbated downwards. In the natural seed bank, A. tripolium and S. anglica were practically absent while S. procumbens occurred more frequently. The viability of S. procumbens seeds was highest at the surface, between 80% and 90%. The viability quickly decreased with depth, although viable S. procumbens seeds occurred up to 15 cm depth. Only when seeds were supplied after winter, many S. procumbens and some S. anglica individuals did establish successfully in the transition zone. Viable seed availability formed a vegetation establishment threshold, even with a local seed source. Our results suggest that, although boundary conditions such as elevation, inundation, and weather conditions were appropriate for vegetation establishment in spring, the soil surface in winter can be so dynamic that it limits lateral marsh expansion. These insights can be used for designing effective nature-based coastal protection.@en

Contributed

1 records found

Recycling permanent magnets from offshore wind turbines

An e-waste approach

Master thesis - F.F. de Waal, S.T. Abrahami, Marin van Regteren, Jonas P. Jensen

OWTs and WEEEs have both been found to contain NdFeB permanent magnets, which are both valuable sources for the recovery of REEs. At the same time, OWTs have been found to contain many electrical components that may not officially fall under the WEEE direct but share many similarities with WEEE. While there is little known about the recycling of OWTs and their electrical components due to their recent introduction, the recycling of WEEE has been studied more extensively and is a more mature industry. To determine the preferred recycling route for permanent magnets from OWTs, a comparison was made with the characteristics and the recycling routes of permanent magnets from WEEE. The disassembly was found to be the most critical part to enable an efficient recycling process, leading to the objective of how can permanent magnets be disassembled from OWT generators. It was found that the disassembly of magnetised magnets at the scale of OWTs is challenging due to the forces required to move them and the brittleness of the materials. For efficient disassembly, the permanent magnets need to be locally and thermally demagnetised. Through a series of interviews, desk research, a lab visit and a site visit to Cuxhaven a concept for the disassembly of permanent magnets from OWTs was developed. It was found that induction heating a copper coil wrapped around U shaped core to transfer heat to the permanent magnet via conduction is a potential scalable, automatable and time-efficient solution for demagnetisation. The power required to heat the coil depended predominantly on the time taken to heat the core as well as the contact surface area of the core with the permanent magnet, the mass of the conductor and the material chosen for the conductor. After thermal demagnetisation, the magnet can be removed while the magnetic is still hot or after cooling, dependent on the thermal expansion coefficient, effect of re-magnetisation and remanence of the magnet. Depending on the acceptable remanence to be able to handle the magnet, it may not be necessary to heat the magnet up all the way to the Curie temperature. The solution proposed in this study is just one of many options towards the recycling of permanent magnets, thus alternative solutions such as direct induction of complete thermal demagnetisation should also be considered.