| 1. |
- Kordas, Olga, et al.
(författare)
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A study on mathematical short-term modelling of environmental pollutant transport by sea currents : The lagrangian approach
- 2017
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Ingår i: Journal of Environmental Accounting and Management. - : L and H Scientific Publishing, LLC. - 2325-6192 .- 2325-6206. ; 5:2, s. 87-104
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with short-term modelling of pollutant transport on the sea surface after environmental accidents. Using the Lagrangian approach, a two-dimensional model of pollutant flow is developed to determine the average velocity field of the flow in the presence of tidal currents and sea surface wind stress for an arbitrarily shaped coastline. This approach assumes that the main transport mechanism is convection. Short-term scenarios are considered, where diffusion effects on pollutant transport can be neglected. The hydrodynamic problem is solved by the method of discrete singularities adapted to fluid advection problems. The problem of environmental pollutant transport by sea currents is reduced to integration of the advection equations to determine the spatio-temporal properties of the spreading pollution. The model was verified through comparison of the results against natural observations on the spread of an oil spill on the sea surface following a collision between the Chinese bulk carrier Fu Shan Hai and the Cyprian container ship Gdynia near the island of Bornholm in the Baltic Sea (May 31, 2003). Satisfactory agreement was found between results of a 7-day numerical simulation and observed data. The proposed model can therefore be used for real-time prediction of short-term pollutant transport on a sea surface with an arbitrarily shaped coastline, to support decision-making processes during maritime accidents, in particular oil spills.
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| 2. |
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| 3. |
- Kordas, Olga, et al.
(författare)
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Similarity problems for steady state geothermal systems
- 2014
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Ingår i: International Journal of Fluid Mechanics Research. - : Begell House. - 1064-2277. ; 41:6, s. 547-555
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Tidskriftsartikel (refereegranskat)abstract
- Increasing energy efficiency of the geothermal systems (GS) is an important task for further development and implementation of the geothermal energy for industrial and domestic heating and cooling. Achieving the higher efficiency, in its turn, requires insight into thermodynamic interaction of all elements of GS. Mathematical modeling of such systems, as well as the development of similarity methods for such modeling is highly relevant because of the high cost of the GS. The presented in the paper mathematical model of a strongly non-equilibrium thermodynamic systems Ground - Borehole Heat Exchanger - Ground Source Heat Pump has been elaborated to describe the energy exchange between the ground, BHE and GSHP. Based on this model a stationary problem of such system operation has been solved. A new type of non-equilibrium spatial scales for this problem, not depending on its geometric parameters and that are determined by energy characteristics of GS are introduced. It is shown that in the special variables considered problem is characterized by a unique dimensionless parameter - the ratio of the thermal conductivity of the ground and brine. This allows us to formulate new approaches to GS modeling.The physical interpretation of the received results is provided.
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| 4. |
- Mulder, K. K., et al.
(författare)
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being scared is not enough! motivators for education for sustainable development
- 2013
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Ingår i: Sustainability Assessment Tools in Higher Education Institutions: Mapping Trends and Good Practices Around the World. - Cham : Springer Berlin/Heidelberg. - 9783319023755 ; , s. 29-45
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter presents an overview of positive motivators for students, lecturers, and educational managers to prioritize Sustainable Development in education. Very often, we implicitly assume that students and colleagues should all be motivated by the great challenges that the world faces. And if they appear not to react sufficiently to these challenges, we sometimes tend to give these challenges an apocalyptic character. But is this the right motivator for students and colleagues to work on Sustainable Development? We all know that if you only use a stick and no carrot… So why don’t we use more carrots? The bureaucracy that comes with tools for checking/auditing/evaluating the (SD content of) programs/curricula is not particularly a strong motivator for university lecturers. And building courses that add another subject to the erudition of the graduate might not be the right motivators for students that want to make a difference. We are often still in the process of convincing university managers to add SD to the curriculum, convincing colleagues to address SD, and convincing students to pick SD electives and address SD in their projects. How to motivate them to do this when this gives them no direct personal reward and even might increase their workload? The paper will explore options to develop motivating educating by reviewing case studies on educational renewal in four universities. It concludes that there are various options for more motivating education. However, to fully utilize these options, more priority should be given to education.
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| 5. |
- Voloshchuk, V., et al.
(författare)
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Comprehensive energy and exergy analysis of the Ground Source Heat Pump evaporator
- 2021
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Ingår i: ECOS 2021 - 34th International Conference on Efficency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - : ECOS 2021 Program Organizer. ; , s. 1436-1445
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Konferensbidrag (refereegranskat)abstract
- The paper deals with the elaboration and application of the phenomenological mathematical model of the vertical ground heat source and comprehensive energy and exergy analysis of ground heat source-evaporator system of the ground source heat pump. The novelty of the proposed model, with comparison to the conventional engineering approaches, is derived from the description of a ground source and evaporator as a nonequilibrium thermodynamic system consisting of ground (a source of low temperature energy) and a finite cylindrical borehole filled with fluid (the energy carrier) flowing through it and with continuity of temperature and energy fluxes boundary conditions between ground and fluid. It is shown that the studied problem is characterized by only dimensionless parameter - the ratio of the thermal conductivities of the ground and flowing fluid. The designed mathematical model has been used for study of quantitative and qualitative characteristics of extractable energy. Further, a thermodynamic scheme of the heat pump evaporator as a converter of low potential geothermal energy of secondary fluid into freon energy due to phase transition is proposed. A definition of an exergy efficiency of the evaporator of the ground source heat pump and the fundamental energy characteristic of the ground source of heat have been introduced in the paper and the physical interpretation of the received results has been provided. The designed mathematical model has been used for study of quantitative and qualitative characteristics of extractable energy using exergy analysis. The proposed ground heat source and evaporator models for heat pumps enables the creation of new engineering techniques for calculations of energy capacity of borehole heat exchangers for Ground Source Heat Pumps (GSHP). Besides, the suggested theory can be used for elaboration of the new scientific–technological approaches to creating optimum strategies for design, control and operation of Heat Pumps.
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