| 1. |
- Allgurén, Thomas, 1986, et al.
(författare)
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Investigation of the Behavior of Alkali Chlorides during Sulfur Recirculation in a Waste-to-Energy Facility
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- High temperature corrosion related issues are known problems for Waste-to-Energy facilities where the formation of alkali chlorides is among the most problematic species formed during the combustion. Sulfur Recirculation is a novel technology developed to reduce the chlorine content in the ash and in that way also the corrosivity of the ash. This concept has been installed at the Maabjerg Energy Center (MEC) in Denmark. This work aims to take a first step towards a reaction kinetics based model that can describe systems like the MEC boiler and to evaluate the impact of Sulfur Recirculation. This is done by implementing a plug flow reactor model in the software Chemkin. Previously obtained data from on-site experiments and CFD simulations is used as input to the model. The model is focused on describing the sulfation of alkali chlorides and the result from the model is compared to experiments. The model is able to predict the degree of sulfation with less than 10% deviation from the experimental results. Both the experiment and the model show a clear benefit from implementing sulfur recirculation which lowers the chlorine content in the up to as much as 70%. It is, however, also shown that the results are sensitive towards several of the assumptions made. Even though there is a relatively good agreement in final sulfation between model and experiments the model is not able to represent the detailed chemistry in a realistic way in its current state; further development is required.
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| 2. |
- Gäre, Klas, 1948-, et al.
(författare)
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Evidence informed healthcare improvement : Design and evaluation
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Healthcare is in constant change with fast development in knowledge, new technology and varying needs and expectations from patients, citizens, management, and politicians. There is a challenge in balancing the involved actors´ focus, needs, preferences, and resources for healthcare improvement. Improvement of healthcare is an ongoing activity, sometimes managed and controlled, often not. A key ingredient for success is competence where the need for competence varies with perspectives of the improving actors. Actors in healthcare improvement are professionals, patients, politicians, management, citizens, researchers, research foundations and others. In this report a review of frameworks in healthcare improvement are presented together with management myths and questions around needs for healthcare improvement competence and capabilities currently on the agenda.Most improvement initiatives of some size have substantial parts of IT and have had so for a considerable time. This rather long experience of more and less successful IT implementation and use is transparent and useful in all kinds of healthcare improvement. One important issue in this report is what has real impact is the actual understanding and use of innovations and artefacts by healthcare actors in a broad sense for healthcare improvement (e.g., new clinical evidence, clinical guidelines, process changes, information systems and more). The aim in this report is to review frameworks which can be useful in healthcare improvement as well as in the study of healthcare improvement.Conclusions concern what is found to be important to study and understand healthcare improvement, considering the presented frameworks. Improvement of healthcare is present in all the frameworks but in different ways and what is emphasized concerning scope and focus. Improving healthcare take place in the interaction of at least two parts, one of which is healthcare professionals, and another is the patient/next-of-kin. Professionals and patient populations interact in processes of social networks and structures. Actors and context are useful concepts for understanding action (use) and its social contexts. The actual use of innovations is best understood in terms of integration into clinical activities and processes – actors’ interaction, coordination and communication activities and processes.Theoretical implications are that there is a need for more research concerning meso and macro perspectives on methods for healthcare improvement, and the interplay of perspectives regarding the understanding of improvement in healthcare. Of course, a challenge is that the objects of improvement are complex adaptive systems of healthcare is not easily to catch in simple rules. They are genuinely difficult both to change and evaluate changes. Practical implications of the report support design and contents of education programs in improvement of healthcare, in better understanding usefulness, practice, use, and experience base. To help the understanding of the need and usefulness of integrating different perspectives for successful healthcare improvement, e.g., micro, meso, and macro perspectives, use of mixed methods and more.
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| 3. |
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| 4. |
- Andersson, Klas, 1968-
(författare)
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Improving Fixed Wing UAV Endurance, by Cooperative Autonomous Soaring
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ever-expanding use and development of smaller UAVs (Unmanned Aerial Vehicles) has highlighted an increasing demand for extended range and endurance for this type of vehicles. In this thesis, the development of a concept and system for autonomous soaring of cooperating unmanned aerial vehicles is presented. The purpose of the developed system is to extend endurance by harvesting energy available in the atmosphere in the form of thermal updrafts, in a similar way that some birds and manned gliders do. By using this “free” energy, considerable improvements in maximum achievable endurance can be realized under a wide variety of atmospherical and weather conditions. The work included theoretical analysis, simulations, and finally flight test- ing of the soaring controller and the system. The system was initially devel- oped as a single-vehicle concept and thereafter extended into a system consist- ing of two cooperating gliders. The purpose of the extension to cooperation, was to further improve the performance of the system by increasing the ability to locate the rising air of thermal updrafts. The theoretical analysis proved the soaring algorithm’s thermal centering controller to be stable. The trials showed the concept of autonomous soaring to function as expected from the simulations. Further it revealed that, by applying the idea, extensive performance gains can be achieved under a fairly wide variety of conditions. The cooperative soaring, likewise, functioned as anticipated and the glid- ers found, cooperated, and climbed together in updrafts. This represents the first and presumably only time cooperative autonomous soaring in this way, has been successfully demonstrated in flight. To draw further conclusions on the advantages of cooperative soaring additional flight trials would, however, be beneficial. Possible issues and limitations were highlighted during the trials and a number of potential improvements were identified. As a part of the work, trials were conducted to verify the viability to implement the system into “real world” operational scenarios. As a proof of concept this was done by tasking the autonomous gliders to perform data/communications relay missions for other UAV systems sending imagery to the ground-station from beyond line of sight (BLOS). The outcome of the trials was positive and the concept appeared to be well suited for these types of missions. The comms relay system was further developed into a hybrid system where the optimal location concerning relay performance was autonomously sought out, after-which the attentiveness then switched to autonomous thermal soaring in the vicinity of this ideal relay position. The hybrid system was tested in simulation and partially flight tested.
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| 5. |
- Andersson, Klas, 1968-, et al.
(författare)
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Thermal highs and pitfall lows - notes on the journey to the first cooperative autonomous soaring flight
- 2012
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Ingår i: 2012 IEEE 51st IEEE Conference on Decision and Control (CDC). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3392-3397
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Konferensbidrag (refereegranskat)abstract
- This paper discusses the development and flight testing of an algorithm for cooperative soaring by multiple autonomous gliders. Flight test results confirmed that the algorithm functioned as expected and that the gliders worked cooperatively to find and utilize the same updrafts during the test. However, the flight also indicated that the effectiveness of the strategy depends largely on the existing thermal conditions in combination with how restrictively the limits of separation be tween the cooperating gliders are set. To the best of the authors' knowledge this was the world's first cooperative autonomous thermal soaring flight.
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| 6. |
- Andree, Maria, et al.
(författare)
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Knowledge Products from Close-To-Practice Research
- 2024
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Ingår i: Round table presentation at the NERA-conference, 6-8 March, Malmö University.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- ‘Close-to-practice research’ has received increased attention across the Nordic countries. Following the British Education Research Association (BERA), the notion of ‘close-to-practice research’ is used to refer to educational research that is based on problems in practice, often involves researchers working in partnership with practitioners in schools and addresses issues of relevance to practitioners. This roundtable focuses on how close-to-practice research can contribute to the knowledge base of the teaching profession by bringing together perspectives from didactics, school improvement and educational policy. More specifically, the interest is directed toward what characterizes the knowledge produced through practice-based research that may have significance for teachers' professional knowledge base and practice. The roundtable conversation builds on a previous analysis of what kinds of knowledge products are generated in didactic close-to-practice research where teachers and researchers work together within the research environment Stockholm Teaching & Learning Studies. As a result of this analysis a typology of knowledge products was proposed including: (i) descriptions of knowing, (ii) teaching design, (iii) didactic examples and (iv) methodological tools. It has been proposed that additional knowledge products may be developed, such as artifacts to be used in teaching (e.g. lesson plans, visual representations). The roundtable will include the following points of discussion: 1) a brief presentation of the typology, 2) challenging and developing the typology of knowledge products proposed by previous research by investigating different cases of close-to-practice research from traditions of action research and practice-developing research within subject-didactics, and 3) discussing how the notion of knowledge products may contribute to advancing the conversation on cumulativity in the field of educational research in general, and in relation to syntheses of close-to-practice research in particular. The participants will be engaged in conversations on the desirability and feasibility of striving towards cumulativity.
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| 7. |
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| 8. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 9. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 10. |
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