Are you looking for a thesis theme?

On the following pages you will find ideas for a thesis theme including contact person.

If you are not really into any of these ideas, but still think DHI is an interesting place or maybe you have an idea of your own you are very welcome to give it a try and contact us. Contact person: Ole Mark (omj@dhigroup.com).

Updated 29-11-2012

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M.Sc.: Renewable Energy production from tidal currents in the Strait of Messina, ItalyTo continually support the future harvesting of renewable energy resources, it is expected that tidal current constitute an important contribution in selected geographic areas. Tidal currents and ranges in the Mediterranean basin are generally low from a tidal energy perspective. The narrows through the Strait of Messina are an exception, exhibiting intensive tidal currents that have the potential for the economic exploitation. Maximum current velocities at spring peak tides through the Strait vary between 1.8m/s to more than 3m/s. The Master thesis will be based on establishing a 3D baroclinic model using the DHI software MIKE 3 FM to study the stratified flow in the area and map the potential tidal energy in three dimensions. Good physical understanding and modeling capability will be developed to address this challenge.

Contact: Jacob Tornfeldt Sørensen, jts@dhigroup.com

M.Sc.: Current modeling in the KattegatThe Kattegat is a very dynamic transition area between brackish Baltic water and saline North Atlantic water. The combination of wind and pressure driven circulation, tides, strong stratification and fronts lead to strong variations in water level, temperature, salinity and currents ultimately setting the conditions for marine ecosystems, oxygen depletion etc. The master student will model the area in different resolutions to determine the role of horizontal and vertical resolution and hence resolved physical processes on stratification and current patterns near Anholt and Læsø. The thesis will conclude on the impact of high resolution processes for the Kattegat circulation.

Contact: Jacob Tornfeldt Sørensen, jts@dhigroup.com

Ph.D.: Prediction of mesoscale circulation and tides in local high resolution in the North AtlanticAt North Atlantic basin scale, oceanographic models typically do not include tidal dynamics. Shelf scale oceanographic models (e.g. MIKE 3 FM) normally use tidal and wind driven circulation as part of their prime forcing. Satellite altimetry missions measure the relative sea surface quite accurately and this has been used to calculate tidal constituents at global scale. Recently, the geoid and its uncertainty have become much more accurately described through the GOCE and GRACE satellite missions. Prediction of currents and water level in deep sea, shelf and shelf break regions in general requires combining the large and mesoscale ocean circulation from regional models with local model downscaling and inclusion of tidal as well as mesoscale signals measured by satellite altimetry and its absolute interpretation via recent geoid estimates.

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The Ph.D. student will address the following questions:- How are mesoscale and submesoscale ocean currents and tidal signals best combined with

altimetry, geoid models and sea surface temperature observation via data assimilation to predict the three-dimensional velocity structure in deep seas and at the shelf break?

- How is basin scale models best combined with novel finite volume modelling techniques (MIKE 3 FM) for modelling submesoscale dynamics including tidal dynamics?

Contact: Jacob Tornfeldt Sørensen, jts@dhigroup.com - Note: this is only a suggestion for a theme, scholarship has to be arranged.

M.Sc.: Properties of cohesive sediments in the marine environmentFine grained sediments are different from sand in being cohesive. This means that in the marine environment the single mineral grains can adhere into larger aggregated known as sediment flocs. These flocs have completely different properties than either sand grains or the individual grains that compose the floc.

Institute for Geography and Geology have during the recent decades collected and analysed a large number of sediment data from a range of locations in Denmark and the rest of Europe. DHI has used numerical models in connection with collected data to describe erosion, transport and deposition of fine grained sediment.

In connection with the increasing number of offshore constructions (e.g. bridges, tunnels, wind farms etc) there is currently a huge demand for detailled knowledge about sediment dispersion in connection with the construction works.

The project is proposed in collaboration between IGG and DHI. The work can focus on detailled measurements made before or during construction work or numerical modelling of processes or general transport patterns. Contact: Ulrik Lumborg, DHI. ulu@dhigroup.com

M.Sc.: Nanomaterials environmental fate and effectsNanotechnology has opened up new and exciting uses of chemical substances. The explanation is that materials in their nanoform behave differently than chemicals and materials in their bulk form. This also means that, our knowledge of the fate and hazards of chemicals in their bulk form cannot directly be transferred to nanomaterials. DHI is examining the ecotoxicological profile of different nanomaterials e.g. in the EU-project Nanopolytox (www.nanopolytox.eu).

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Project proposal: Evaluation of the environmental fate and effects of nanomaterials including the adjustment of existing test methods, in order to make them applicable for the evaluation of nanomaterials. Focus will be on methods that aim to clarify the environmental fate of nanomaterials i.e. studies on transport in soil, water and sediment as well as bioaccumulations. It will also be possible to work with in-vitro testing with zebra fish embryos.

Contact: Margrethe Winther-Nielsen, mwn@dhigroup.com

M.Sc.: Persuasive e-leaning resources to understand chemical exposure scenariosLearning objectives and technologies are currently limited in their adaptability and how far they support active engagement from the learner. DHI is a partner of the EU supported project EuroPLOT (Persuasive Learning Objects and Technologies for Lifelong Learning in Europe) lead by Leeds Metropolitan University. The project will develop a pedagogical framework for active engagement, based on persuasive design and demonstrate its value by creating authoring tools and exemplars of persuasive learning objects and technologies that are easy to create and adapt. One of these learning objects is focusing on e-learning activities directed to employees in the European chemical industry.

Project proposal: Developing of persuasive learning objects for training vocational learners to understand regulations for exposure scenarios for handling of chemical mixtures according to the EU chemical regulation REACH. Manufactures and importers of chemical substances are developing exposure scenarios as part of their registration dossiers. How to handle these exposure scenarios downstream in the supply chain, especially for formulators of a mixture, is a big challenges and calls for new instruments including persuasive learning.

Contact: Margrethe Winther-Nielsen, mwn@dhigroup.com

M.Sc.: Lake modelling and lake restorationLake Furesø (the deepest lake in Denmark) are under restoration with oxygenation. Nutrient load have been reduces during the last decades. DHI have established a 3D hydrodynamic model and a water quality and eutrophication model. The model have to a certain extent been calibrated. However there is still room for improvement both in relation to describing the water circulation within the lake, the oxygenation of deep water masses as well as improvement in the ecological model and the interaction between sediment and water column. After modification of the existing model and recalibration, the model can potentially be used for better understanding the dynamic in the lake, consequences of human induces impact and more general expectation to for future development. Impact of changed nutrient load, climate changes, biomanipulation could be issues to

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be analyses. It is furthermore relevant to evaluated the strength and limitation of using modelling approached in water management of lakes.

The existing model have been set-up in DHI model software MIKE3 utilisation of the ecological modelling module ECOLab. Depending on focus for the project background in hydrodynamic and/or lake ecology is required. Basic knowledge about modelling is an advantage but not an absolute request. Basic knowledge about mathematics is required.

Contact: Jørgen Krogsgaard Jensen, jok@dhigroup.com and Rikke Margrethe Closter, rmc@dhigroup.com

M.Sc.: Describing and predicting the dynamic habitat of pelagic feeding birdsThe distribution of species can be explained by relating environmental variables to observed occurrences or abundance of species. Species distribution models are usually static, describing a snapshot in time. The habitat of, particularly, pelagic feeding birds are highly dynamic, however. This can be accounted for by extracting oceanographic variables based on both position and time. The models can thereafter be used for predicting the distribution of birds during different conditions, for example high or low tides. The relationship between pelagic species and their environment is still poorly understood and needs to be studied more closely. Key questions are for example: Which variables are the most important? How can different states of the pelagic environment be defined to get most out of species distribution models?. At DHI seabird observations and oceanographic model data are available from several case studies in the Danish waters, North Sea and the North Atlantic.

Contact: Henrik Skov, hsk@dhigroup.com

M.Sc.: Investigating the relationship between weather and bird migrationAlthough it is generally known that weather conditions influence the migration of birds it remains a challenge to quantify the nature of this relationship. This is partly due to the obvious difficulties in

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making systematic recordings of migrating birds beyond the visual range of human observations as well as during the night. Intensive studies of bird migration from southeastern Denmark have provided a large amount of radar-based, acoustic and visual observations which may be analysed with the aim to throw new light on the relationship between the migration intensity of different bird species and weather parameters. Key questions are: how important are local weather conditions as compared to regional migration intensities in determining the number of birds migrating at specific sites ?. Under which wind conditions do birds choose to depart land and cross the Baltic Sea ?.

Contact: Henrik Skov, hsk@dhigroup.com

M.Sc.: Modeling behavior of marine mammals and their response to noise pollution from human activities using Agent-Based modelling

Human activities at sea such as drilling, pile driving, seismic surveys and ship traffic all creates noise pollution which may have a potential impact on the distribution and migration patterns of large marine organisms including marine mammals. In severe cases physical damages to the animals have been observed. Prior to all larger marine constructions or activities producing significant noise levels environmental impact assessments need to be conducted including the potential impact on marine mammals. The project aims at testing and developing agent-based models describing the basic behavior and migration patterns of specific species of marine mammals prior to and during periods of noise exposure. The tools applied will be DHIs newly developed Agent-based modeling platform for combining agent-based modeling with hydro-dynamic modeling and classical water quality modeling. The model can be tested and validated based on existing data on species distribution and published studies on movement behavior derived from satellite tagging.

Contact: Flemming Thorbjørn Hansen, fth@dhigroup.com

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M.Sc.: Predicting the behaviour of freshwater fish in a small lake using agent-based modellingIndepth understanding on how to describe and model individual fish behavior and schooling has wide applications within area such as environmental impact assessment, management of fisheries, nature conservation and aquaculture production optimization. In particular the link between individual behavior and schooling, internal physiological processes (e.g. bioenergetics, growth) and external environmental parameters (e.g. temperature, food abundance, water transparancy) is important to understand. Based on an extensive data set from a recent phd study including acoustic tagging of several species of freshwater fish (e.g. pike, roach and perch) in a small Danish lake this project will aim at developing agent-based models linking the observed behavior of individual fish with both internal and external parameters.

Contact: Flemming Thorbjørn Hansen, fth@dhigroup.com

Some other ideas - Environmental impact assessment (EIA) of wind mill farms. Comparison of methods in e.g.

Poland, Germany and Denmark.- Behavioural modelling of birds and marine mammals- Benthic fauna at oil drilling platforms in the North Sea- Water Framework Plans, implementing tools and dynamic models in Danish estuaries- Modelling of aquaculture and mussel farms

Contact: Andreas Brogaard Buhl (abb@dhigroup.com)

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