| 1. |
- Andersson, Simon, 1980-
(författare)
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Skälig misstanke
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral dissertation studies the legal standard of proof called reasonable suspicion (skälig misstanke). This standard is central for criminal investigations as the majority of state criminal procedural actions (tvångsmedel) are tied to it, as well as the majority of a suspect’s rights. Despite the central role played by this standard, it has not to any significant extent been researched previously. What the standard entails cannot be seen from either the law or legislative history, and there are no published cases discussing it. As the meaning of the standard is not clear, there is much room for discretion in assessments as to whether the standard has been met. There consequently is a need to clarify what reasonable suspicion entails. What is required to fulfill the standard? How is reasonable suspicion to be assessed? These questions are answered in this dissertation.My investigation demonstrates that reasonable suspicion is a three-pronged standard:A requirement of preponderance of the evidenceReasonable suspicion entails a requirement of a preponderance of the evidence (sannolikhetsövervikt). This means, somewhat simplified, that it should be more probable that the suspect is guilty than innocent. The hypothesis underlying the reasonable suspicion of alleged guilt (gärningshypotesen) should be more probable than all other plausible hypotheses combined.A requirement of individualizationThe evidence must be sufficiently individualized in order to reach the level of reasonable suspicion. The requirement of individualization is in place to prevent that persons are suspected on the basis of group membership. The same is true with respect to persons belonging to groups where the probability of crime is generally high. In such situations, there must be a concrete circumstance pointing to just that person committing a certain crime. It can be, however, circumstances having very low evidentiary value. Group membership can still be of significance with respect to the suspect, but reasonable suspicion cannot be solely based on group membership. A generally applicable concept as to that distinguishing the general from the individual cannot however be articulated. All evidentiary evaluations are in some form based on generalizations. Consequently, the issue of whether the evidence is sufficiently individualized must be assessed from case to case. The main premise is that suspicion cannot be solely based on group belonging. This is a legal-political requirement. Legal-political aspects consequently must also be taken into consideration when evaluating evidence.A requirement of robustnessEven in cases where the evidence is evaluated so that a preponderance of the evidence exists and is sufficiently individualized, the evidence still needs to be sufficiently robust. Robustness is a measure of whether good grounds exist for the conclusion. It is not a question of how ”strong” the evidence is, but rather how thoroughly the situation has been investigated. Somewhat simplified, it is a question of ”how much” evidence exists rather than the strength of the individual pieces of evidence. This requirement of robustness varies depending upon time in that it is very low at the commencement of an investigation, but as time goes by, higher requirements are placed as to the ”completeness” of the investigation.
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| 2. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Gårdebjer, Sofie, 1985, et al.
(författare)
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The impact of interfaces in laminated packaging on transport of carboxylic acids
- 2016
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Ingår i: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 518, s. 305-312
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Tidskriftsartikel (refereegranskat)abstract
- The permeability of oleic and acetic acid through low density polyethylene (LDPE) and ethylene acrylic acid (EAA) have been measured using diffusion cells. In addition, the permeability through combinations of LDPE and EAA in the form of laminates with different numbers of layers has been determined. Oleic acid shows an almost 30 times higher permeability compared to acetic acid, which was partly explained by the adsorption of oleic acid to the film surface during the permeability experiment. In addition, the permeability is lower for both oleic and acetic acid in the laminates compared to the pure films. The decreased permeability can be explained by the presence of crystalline domains close to the interface. This is supported by SAXS data which suggests an ordering of polymer chains in the EAA film close to the interface. In summary, the results show that it is possible to create barrier materials with decreased permeability, which is interesting for example in the packaging industry.
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| 4. |
- Strand, Magnus, 1977-
(författare)
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The Passing-On Problem in EU Law Damages and Restitution
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, the so-called passing-on problem is examined for the purposes of EU law. The passing-on problem may arise when an amount has been charged unlawfully, in whole or in part, and paid by a commercial enterprise. If the charge was contrary to EU law, the payer will usually claim the amount back by way of an action for restitution or damages. However, it has been counter argued that the amount cannot be claimed back by the payer, because it has been passed on to the next level of the supply chain. Under such circumstances, it must be determined who should be able to claim what portion of the original charge from whom, and whether it is also possible to claim for reduced sales due to an increased selling price.In this thesis, the main EU law issues triggered by passing-on are identified; ie access to court, substantive proximity (eg causation), and the estimation of awards. In the assessment, actions are distinguished with regard to the type of respondent targeted. Accordingly, actions against the EU, against a Member State, and against private individuals are all examined individually. In respect of actions brought against private individuals, EU law has so far only required for private individuals to be liable in damages for a breach of EU competition law. It is examined whether an action for restitution should equally be available under such circumstances. It is also separately examined whether horizontal liability in damages and/or restitution can be more generally available for a breach of EU law. Reasoned suggestions for solutions to all these EU law issues are offered, both in the course of discussions and in the final conclusions.It is emphasized that the passing-on problem in EU law does not only fall under the jurisdiction of the EU legislature and EU Courts, but also of the Member States. It is also noticed that the legal context has an impact on the EU law issues examined. It is finally submitted that a mixed restitution/damages approach offers the best opportunity to reconcile the various interests at stake in the passing-on problem.
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| 5. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 6. |
- Ahangari, Alebtekin, et al.
(författare)
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Acute intermittent porphyria symptoms during the menstrual cycle
- 2015
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Ingår i: Internal medicine journal (Print). - : Wiley. - 1444-0903 .- 1445-5994. ; 45:7, s. 725-731
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Tidskriftsartikel (refereegranskat)abstract
- Background: Acute intermittent porphyria (AIP), a life-threatening form of the disease, is accompanied by several pain, mental and physical symptoms.Aims: In this study, we evaluated the cyclicity of AIP and premenstrual syndrome (PMS) symptoms in 32 women with DNA-diagnosed AIP during their menstrual cycles, in northern Sweden.Methods: The cyclicity of AIP symptoms and differences in them between the follicularand luteal phases, and the cyclicity of each symptom in each individual woman indifferent phases of her menstrual cycle were analysed with a prospective daily ratingquestionnaire. PMS symptoms were also evaluated in the patients on a daily rating scale.Results: Of the 32 women, 30 showed significant cyclicity in at least one AIP or PMS symptom (P < 0.05–0.001). Back pain (10/32) was the most frequent AIP pain symptomand sweet craving (10/15) was the most frequent PMS symptom. Pelvic pain (F = 4.823,P = 0.036), irritability (F = 7.399, P = 0.011), cheerfulness (F = 5.563, P = 0.025), sexualdesire (F = 8.298, P = 0.007), friendliness (F = 6.157, P = 0.019), breast tenderness (F =21.888, P = 0.000) and abdominal swelling (F = 16.982, P = 0.000) showed significantcyclicity. Pelvic pain and abdominal swelling (rs= 0.337, P < 0.001) showed the strongest correlation. The age of women with latent AIP was strongly correlated with abdominal swelling during the luteal phase (rs= 0.493, P < 0.01).Conclusion: Our results suggest that the symptoms of AIP patients change during their menstrual cycles.
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| 7. |
- Aho-Mantila, L., et al.
(författare)
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Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET
- 2017
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 59:3
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Tidskriftsartikel (refereegranskat)abstract
- The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.
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| 8. |
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| 9. |
- Andersson, A., et al.
(författare)
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Electrical machine acoustic noise reduction based on rotor surface modifications
- 2017
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Ingår i: ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings. - 2329-3721. ; , s. Art. no. 7855075-
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Konferensbidrag (refereegranskat)abstract
- © 2016 IEEE.Electromagnetic acoustic noise from electrical machines has increasingly become an area of attention for both academia and industry. In electric propulsion systems, this is a main contributor to the total acoustic noise and it is usually perceived as annoying due to its tonal appearance. This paper presents an alternative rotor design for a permanent magnet synchronous machine with the objective to decrease prominent machine orders in the acoustic noise by force density harmonics minimization. Apart from this, torque characteristics and core losses are included in the study as well, in order to investigate possible adverse effects. In the proposed design, irregularities are introduced in the rotor surface to suppress harmonics in the flux density by locally altering the airgap permeance. The analysis is based on finite element modelling, using a sequentially solved, weak coupled, multi-physics approach which enables separation of the electromagnetic-, structural dynamical- and acoustic problems. The results show that the most prominent harmonics in the acoustic noise can be reduced without significantly deteriorating the dynamic performance. It is also demonstrated that the core losses of the machine is positively affected by the obtained harmonic magnitude reduction in the flux density. Although the paper focuses on minimization of radial force density harmonics, the results indicate that the approach and the methodology may also be used for torque harmonics minimization.
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| 10. |
- Andersson, A., et al.
(författare)
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Experimental determination of inverter losses and sound consequences of using DPWM in an HEV
- 2017
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Ingår i: Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC. ; , s. 1382-1388
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Konferensbidrag (refereegranskat)abstract
- This paper presents an experimental determination of the inverter losses and acoustic noise consequences of using discontinuous PWM in a hybrid/electric vehicle application. Acoustic noise and stator vibrations were evaluated using measurements and inverter losses were evaluated both with the use of measurements as well as simulations. The entire operational area for positive torque was covered in the analysis. The results show that the total inverter losses were decreased with about 10-20% when DPWM was used. The introduction of discontinuity in the voltage modulation affects the harmonic content of the phase current. This was further investigated, both electrically and acoustically, focusing on harmonics around the switching frequency, since these are acoustically challenging in the intended application. Measurements show that the magnitude of phase current harmonics around the switching frequency were increased when discontinuous PWM was used. This increase, in the magnitude of these phase current harmonics, amplifies the corresponding harmonics in the stator vibrations which also increased the associated acoustic noise. Therefore, the acoustic noise radiated from the machine and the inverter was enlarged when discontinuous PWM was used. However, the results also show that the adverse acoustic effects were significantly decreased as the machine was operated in the field weakening area.
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| 11. |
- Andersson, A., et al.
(författare)
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Motion sensorless IPMSM control using linear moving horizon estimation with luenberger observer state feedback
- 2018
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Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; 4:2, s. 464-473
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an investigation of motion sensorless control based on the frame work of moving horizon estimation (MHE), validated experimentally with a rear axle electrical drive unit used in automotive applications. Both steady-state performance and dynamic performance, including speed reversal, are investigated. In addition, a well-established active flux-based observer is implemented and referenced to objectively evaluate the proposed MHE. It is shown that the proposed solution is feasible, that the associated dynamic optimization problem can be solved in real time, while exploiting the attractiveness of the approach to obtain highly accurate estimates. Moreover, the absence of ${d}$-axis flux in the proposed solution is considered a significant strength. Conclusively, it turns the proposed solution into a universal solution for any synchronous motor, regardless of whether a PM, PM-assisted, or reluctance motor is used, nondependent on the presence of magnetic saliency.
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| 12. |
- Andersson, Björn, et al.
(författare)
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PARTIspace. WP2 – National Contexts Comparative Report UNIBO, Italy UGOT, Sweden
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The PARTISPACE study aims at undertaking a comparative analysis of youth participation or their involvement and engagement in decisions 'which concern them and, in general, the life of their communities' (European Commission, 2001a: 8). The central research question of the project is how and where 15- and 30 year-old young people do participate differently across social milieus and youth cultural scenes and across eight European cities (framed by different national welfare, education and youth policies). What styles of participation do they prefer, develop and apply and in what spaces does participation take place? Answers to these questions could improve the understanding of the complexities and contradictions of youth participation – on the side of policy makers as well as on the side of young people – and thereby help empowering young people in participating in society, renovating also concepts, definitions and discourses on what (youth) participation is, could and should be. The eight European cities in which we conduct the study are Bologna (IT), Eskisehir (TK), Frankfurt (DE), Gothenburg (SE), Manchester (UK), Plovdiv (BG), Rennes (FR) and Zurich (CH). They do not represent but secure contrasting contexts of young people’s growing up as well as differing orientations towards Europe. Although embedded in different national and local contexts, these eight cities are comparable in terms of dimension and relevance in the respective country. This ensures a sufficient provision and diversity of participatory settings without being too close to representative national government institutions and umbrella structures.
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| 13. |
- Andersson, Björn, 1952, et al.
(författare)
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WP2.PARTIspace. National Contexts. Comparative Report
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Describes and compares youth policies, social conditions for youth and frameworks for youth participations in eight European cities. The report is a part of the Horizon 2020 project PARTIspace.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Andersson, Sven, 1968, et al.
(författare)
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High Temperature Corrosion and Dioxin Abatement Using Sulfur Recirculation in a Waste-to-Energy Plant
- 2019
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Ingår i: Detritus. - : Eurowaste SRL. - 2611-4127 .- 2611-4135. ; 5:Mars, s. 92-98
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur Recirculation is a novel technique for reducing the high temperature corrosion and dioxin formation in Waste-to-Energy plants by recirculating sulfur from the wet flue gas cleaning back to the boiler. This is achieved by separating SO2 from the flue gas in a wet scrubber downstream of a HCl scrubber. H2O2 dosed into the scrubber reacts with SO, in the gas and produces a 15-25 wt% H2SO4 solution, which is injected into the boiler producing SO2, thus creating a sulfur loop. The first permanent full-scale installation has been in operation in one of the two commercial full-scale Waste-to Energy boilers at Maabjerg Energy Center (MEC) in Denmark since October 2016. The recirculated sulfur increased the gas concentration of SO2 by a factor of 2-3 in the boiler, thereby enhancing the sulfation of corrosive alkali chlorides to non-corrosive alkali sulfates. The chlorine content of the superheater deposits decreased by 85%, and the superheater corrosion rate decreased by 40-90% during the first year of operation. The dioxin concentrations upstream of the dioxin removal system decreased by 75% and the dioxin emissions decreased by 72% with Sulfur Recirculation in operation. Furthermore, the sulfate containing effluent water was almost eliminated due to the increased sulfation of the ashes and deposits.
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| 18. |
- Andersson Sundén, Erik, et al.
(författare)
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An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor
- 2019
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Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 18, s. 147-152
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Tidskriftsartikel (refereegranskat)abstract
- The impurity concentration in the tokamak divertor plasma is a necessary input for predictive scaling of divertor detachment, however direct measurements from existing tokamaks in different divertor plasma conditions are limited. To address this, we have applied a recently developed spectroscopic N II line ratio technique for measuring the N concentration in the divertor to a range of H-mode and L-mode plasma from the ASDEX Upgrade and JET tokamaks, respectively. The results from both devices show that as the power crossing the separatrix, P-sep, is increased under otherwise similar core conditions (e.g. density), a higher N concentration is required to achieve the same detachment state. For example, the N concentrations at the start of detachment increase from approximate to 2% to approximate to 9% as P-sep, is increased from approximate to 2.5 MW to approximate to 7 MW. These results tentatively agree with scaling law predictions (e.g. Goldston et al.) motivating a further study examining the parameters which affect the N concentration required to reach detachment. Finally, the N concentrations from spectroscopy and the ratio of D and N gas valve fluxes agree within experimental uncertainty only when the vessel surfaces are fully-loaded with N.
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| 19. |
- Andersson, Torbjörn
(författare)
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1900-talets fotbollshuvudstad
- 2019
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Ingår i: Idrott. - : Carlsson Bokförlag. - 9789173319485 ; , s. 127-169
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 20. |
- Andersson, Torbjörn
(författare)
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Aesthetic Flexibility : Modularity of Visual Form in Product Portfolios and Branded Products
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increase in competition amongst companies that produce complex or large product portfolios has created a need to utilise modularity strategies not only to flexibly manage technical complexity in a costeffective manner but also for visual appearance. This research aims to understand how the visual appearance of products is affected by modular product development strategies. Specifically, the aim is to understand how such strategies induce constraints and generate possibilities for management of visual appearance in the design process.Five studies have been conducted during the course of this licentiate thesis. Two were conducted with professionals and students in design, while the remaining three are theoretical studies based on findings in the literature, theory building, and experimental research. The goal has been to investigate how designers work when they are put to the task of changing and developing the designs of complex products that are part of a portfolio. The challenge has been to study what suitable strategies exist that manage complex products and product brands, then investigate how these influence designers’ practices.The first study examined how coherence towards a product category influences the design of new products. The outcome of the study was a method to explore visual coherence and diversity in the appearance of a product category.The remaining four studies investigated how modularity, brand management and the redesign of product portfolios influence a design process. The second study described a design phenomenon known as aesthetic flexibility, which was further explored in studies three and five. The outcome from these studies was a proposal for four aesthetic flexibility strategies.The fourth study investigated in what way portfolio extension strategies found in brand management and design research are related, and how such strategies influence aesthetic flexibility. The results from study four were illustrated as a model.The main contribution of this work is the phenomenon of ‘aesthetic flexibility’, which helps understand the factors that influence designers when working with branded modular products. Understanding visual flexibility serves as a starting point in further investigations of how different development strategies affect the possibilities for visual product design.The findings of this work serve to illustrate and explain a complex and multi-facetted design phenomenon which many designers manage more or less intuitively today, thus advancing academics’, teachers’ and professional designers’ understanding of the field.
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| 21. |
- Andersson, Torbjörn, et al.
(författare)
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Aesthetic Flexibility in the Management of Visual Product Branding
- 2015
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Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 3, s. 2191-2198
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Tidskriftsartikel (refereegranskat)abstract
- This paper will investigate the strategic design decision-making of an in-house designer in a company with a large product portfolio, with respect to how designers plan for future visual alterations of the product. In-house designers have to think strategically about the creation of recognition and differentiation through design because they influence the company's overall strategies. Therefore, while balancing aesthetic and semiotic qualities of the product, designers have to consider current as well as future needs for recognition and product differentiation. The ability to do so is affected by cost and brand positioning strategy. An exploratory study was setup to investigate what design strategies could be found in an industrial design team employed by a company. The study exposed how in-house designers could strategically incorporate aesthetic flexibility in product parts in order to create opportunities for faster facelifts or redesigns. The importance of managing carry-over details in larger product portfolios was also discovered. To carry over parts from different products is an important way for a company to save money, development time and at the same time increase brand recognition through repetition. Carry-over can be an aid to enhance visual recognition, but it can also be a hindrance when the designer needs to create differencing design values. Most products have a lifespan before they need to be updated or redesigned, which depends on the competition in a product segment. This makes it extra important for designers to have an understanding of when to incorporate carry-over details and when not to. A model was created to describe how carry-over details, design cues and aesthetic flexibility could be managed in a product portfolio. The model is based on Rune Monö’s works and brand management literature, with an emphasis on the brand positioning framework of Point of Difference, Point of Parity and brand extension by Keller et al.
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| 22. |
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| 23. |
- Andersson, Torbjörn, et al.
(författare)
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Glocal culture, sporting decline? Globalization and football in Scandinavia
- 2019
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Ingår i: Sport in Society. - : Routledge. - 1743-0437 .- 1743-0445. ; 22:4: Sport and Outdoor Life in the Nordic World, s. 704-716
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Tidskriftsartikel (refereegranskat)abstract
- This chapter looks at how globalization has affected and shaped the domestic elite level male football cultures of Scandinavia since the game turned more professional in the region. By drawing on empirical examples from the recent histories of Norwegian, Swedish and, to a lesser extent, Danish football, the authors analyse how the sporting cultures of these countries have changed since the 1970s. The amateur ideologies which had previously dominated football in Scandinavia faded during a period when influences from international and especially professional English football intensified. These influences stretched from playing styles to spectator cultures. While these influences initially made clubs and teams from Scandinavia more competitive in international football, the ‘hypercommodification’ which has dominated top level European football in the new millennium has to a large extent affected Scandinavian football in a negative way in term s of sporting competitiveness. Simultaneously the authors argue that global influences have injected significant fuel and new energy to the spectator cultures evident in a large number of Scandinavian football club communities.
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| 24. |
- Andersson, Torbjörn, et al.
(författare)
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Juridikens termer
- 2015. - 10
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Juridikens termer är ett klassikt uppslagsverk som kortfattat förklarar centrala juridiska termer. Boken är sedan många år ett värdefullt hjälpmedel för verksamma jurister och studerande samt för alla andra som kommer i kontakt med frågor av juridisk natur.
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| 25. |
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| 26. |
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| 27. |
- Angioni, C., et al.
(författare)
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Dependence of the turbulent particle flux on hydrogen isotopes induced by collisionality
- 2018
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Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674 .- 1070-6631 .- 1089-7666. ; 25:8
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Tidskriftsartikel (refereegranskat)abstract
- The impact of the change of the mass of hydrogen isotopes on the turbulent particle flux is studied. The trapped electron component of the turbulent particle convection induced by collisionality, which is outward in ion temperature gradient turbulence, increases with decreasing thermal velocity of the isotope. Thereby, the lighter is the isotope, the stronger is the turbulent pinch, and the larger is the predicted density gradient at the null of the particle flux. The passing particle component of the flux increases with decreasing mass of the isotope and can also affect the predicted density gradient. This effect is however subdominant for usual core plasma parameters. The analytical results are confirmed by means of both quasi-linear and nonlinear gyrokinetic simulations, and an estimate of the difference in local density gradient produced by this effect as a function of collisionality has been obtained for typical plasma parameters at mid-radius. Analysis of currently available experimental data from the JET and the ASDEX Upgrade tokamaks does not show any clear and general evidence of inconsistency with this theoretically predicted effect outside the errorbars and also allows the identification of cases providing weak evidence of qualitative consistency.
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| 28. |
- Angioni, C., et al.
(författare)
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Gyrokinetic study of turbulent convection of heavy impurities in tokamak plasmas at comparable ion and electron heat fluxes
- 2017
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Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 57:2
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Tidskriftsartikel (refereegranskat)abstract
- In tokamaks, the role of turbulent transport of heavy impurities, relative to that of neoclassical transport, increases with increasing size of the plasma, as clarified by means of general scalings, which use the ITER standard scenario parameters as reference, and by actual results from a selection of discharges from ASDEX Upgrade and JET. This motivates the theoretical investigation of the properties of the turbulent convection of heavy impurities by nonlinear gyrokinetic simulations in the experimentally relevant conditions of comparable ion and electron heat fluxes. These conditions also correspond to an intermediate regime between dominant ion temperature gradient turbulence and trapped electron mode turbulence. At moderate plasma toroidal rotation, the turbulent convection of heavy impurities, computed with nonlinear gyrokinetic simulations, is found to be directed outward, in contrast to that obtained by quasi-linear calculations based on the most unstable linear mode, which is directed inward. In this mixed turbulence regime, with comparable electron and ion heat fluxes, the nonlinear results of the impurity transport can be explained by the coexistence of both ion temperature gradient and trapped electron modes in the turbulent state, both contributing to the turbulent convection and diffusion of the impurity. The impact of toroidal rotation on the turbulent convection is also clarified.
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| 29. |
- Angioni, C., et al.
(författare)
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The impact of poloidal asymmetries on tungsten transport in the core of JET H-mode plasmas
- 2015
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Ingår i: Physics of Plasmas. - : AMER INST PHYSICS. - 1070-664X .- 1089-7674. ; 22:5
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Tidskriftsartikel (refereegranskat)abstract
- Recent progress in the understanding and prediction of the tungsten behaviour in the core of JET H-mode plasmas with ITER-like wall is presented. Particular emphasis is given to the impact of poloidal asymmetries of the impurity density. In particular, it is shown that the predicted reduction of temperature screening induced by the presence of low field side localization of the tungsten density produced by the centrifugal force is consistent with the observed tungsten behaviour in a JET discharge in H-mode baseline scenario. This provides first evidence of the role of poloidal asymmetries in reducing the strength of temperature screening. The main differences between plasma parameters in JET baseline and hybrid scenario discharges which affect the impact of poloidally asymmetric density on the tungsten radial transport are identified. This allows the conditions by which tungsten accumulation can be avoided to be more precisely defined.
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| 30. |
- Appel, L. C., et al.
(författare)
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Equilibrium reconstruction in an iron core tokamak using a deterministic magnetisation model
- 2018
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Ingår i: Computer Physics Communications. - : ELSEVIER. - 0010-4655 .- 1879-2944. ; 223, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- In many tokamaks ferromagnetic material, usually referred to as an iron-core, is present in order to improve the magnetic coupling between the solenoid and the plasma. The presence of the iron core in proximity to the plasma changes the magnetic topology with consequent effects on the magnetic field structure and the plasma boundary. This paper considers the problem of obtaining the free-boundary plasma equilibrium solution in the presence of ferromagnetic material based on measured constraints. The current approach employs, a model described by O'Brien et al. (1992) in which the magnetisation currents at the iron-air boundary are represented by a set of free parameters and appropriate boundary conditions are enforced via a set of quasi-measurements on the material boundary. This can lead to the possibility of overfitting the data and hiding underlying issues with the measured signals. Although the model typically achieves good fits to measured magnetic signals there are significant discrepancies in the inferred magnetic topology compared with other plasma diagnostic measurements that are independent of the magnetic field. An alternative approach for equilibrium reconstruction in iron-core tokamaks, termed the deterministic magnetisation model is developed and implemented in EFIT++. The iron is represented by a boundary current with the gradients in the magnetisation dipole state generating macroscopic internal magnetisation currents. A model for the boundary magnetisation currents at the iron-air interface is developed using B-Splines enabling continuity to arbitrary order; internal magnetisation currents are allocated to triangulated regions within the iron, and a method to enable adaptive refinement is implemented. The deterministic model has been validated by comparing it with a synthetic 2-D electromagnetic model of JET. It is established that the maximum field discrepancy is less than 1.5 mT throughout the vacuum region enclosing the plasma. The discrepancies of simulated magnetic probe signals are accurate to within 1% for signals with absolute magnitude greater than 100 mT; in all other cases agreement is to within 1 mT. The effect of neglecting the internal magnetisation currents increases the maximum discrepancy in the vacuum region to >20 mT, resulting in errors of 5%-10% in the simulated probe signals. The fact that the previous model neglects the internal magnetisation currents (and also has additional free parameters when fitting the measured data) makes it unsuitable for analysing data in the absence of plasma current. The discrepancy of the poloidal magnetic flux within the vacuum vessel is to within 0.1 Wb. Finally the deterministic model is applied to an equilibrium force-balance solution of a JET discharge using experimental data. It is shown that the discrepancies of the outboard separatrix position, and the outer strike-point position inferred from Thomson Scattering and Infrared camera data are much improved beyond the routine equilibrium reconstruction, whereas the discrepancy of the inner strike-point position is similar.
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| 31. |
- Arnichand, H., et al.
(författare)
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Discriminating the trapped electron modes contribution in density fluctuation spectra
- 2015
-
Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 55:9
-
Tidskriftsartikel (refereegranskat)abstract
- Quasi-coherent (QC) modes have been reported for more than 10 years in reflectometry fluctuations spectra in the core region of fusion plasmas. They have characteristics in-between coherent and broadband fluctuations as they oscillate at a marked frequency but have a wide spectrum. This work presents further evidences of the link recently established between QC modes and the trapped electron modes (TEM) instabilities (Arnichand et al 2014 Nucl. Fusion 54 123017). In electron cyclotron resonance heated discharges of Tore Supra, an enhancement of QC modes amplitude is observed in a region where TEM cause impurity transport and turbulence. In JET Ohmic plasmas, QC modes disappear during density ramp-up and current ramp-down. This is reminiscent of Tore Supra and TEXTOR observations during transitions from the linear Ohmic confinement (LOC) to the saturated Ohmic confinement (SOC) regimes. Evidencing TEM activity then becomes experimentally possible via analysis of fluctuation spectra.
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| 32. |
- Aslanyan, V, et al.
(författare)
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Gyrokinetic simulations of toroidal Alfven eigenmodes excited by energetic ions and external antennas on the Joint European Torus
- 2019
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Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 59:2
-
Tidskriftsartikel (refereegranskat)abstract
- The gyrokinetic toroidal code (GTC) has been used to study toroidal Alfven eigenmodes (TAEs) in high-performance plasmas. Experiments performed at the Joint European Torus (JET), where TAEs were driven by energetic particles arising from neutral beams, ion cyclotron resonant heating, and resonantly excited by dedicated external antennas, have been simulated. Modes driven by populations of energetic particles are observed, matching the TAE frequency seen with magnetic probes in JET experiments. A synthetic antenna, composed of one toroidal and two neighboring poloidal harmonics has been used to probe the modes' damping rates and quantify mechanisms for this damping in GTC simulations. This method was also applied to frequency and damping rate measurements of stable TAEs made by the Alfven eigenmode active diagnostic in these discharges.
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| 33. |
- Babajan, Tigran, 1986-
(författare)
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Oligarchs, State Power and Mass Opinion : A Study of the Role of Oligarchs in Post-Soviet Pseudo-democracies
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis attempts to understand the role of oligarchs in post-Soviet pseudo-democratic regime trajectories. The two dominant, competing streams of prior work have emphasized either the importance of state power or that of mass opinion in these processes in order to explain why some regimes successfully maintain their grip on power, while others make gradual steps towards democratization. However, the role of oligarchs has been largely overlooked; a gap filled by this study. It employs both widely accepted, as well as unique data to approach the research problem. The work presented in this thesis involves large-N surveys, analyses of media reports and an in-depth case study. There are three key findings:First, for an overwhelming majority of citizens in post-Soviet pseudo-democracies, oligarchs’ actual, negative influence on the political system as well as popular perceptions of unfair wealth concentration are conducive to beliefs that a non-democratic regime is what is needed in order to set things right in their country.Second, the findings from Armenia, Georgia, Russia and Ukraine demonstrate that four politically motivated, rival oligarchs focused on enhancing their reputation and organizational capacity in their struggles for power. In all four countries, regimes used their state power to counter the rival oligarchs. Evidence from Armenia and Russia provides a nuanced understanding of these interactions. In particular, incumbents in these countries used their state power to manipulate public opinion in order to damage the reputation and credibility of the rival oligarchs. This thesis suggests that the main regime leaders do so in order to portray themselves as more trustworthy than their oligarch rivals.Third, a survey analysis of Kyiv university students shows that they view most oligarchs as corrupt and harmful to their political system. According to the survey results, oligarchs’ concentration of wealth appears to disqualify them from being legitimate political players. Yet, further evidence from this thesis suggests that people differentiate between oligarchs as a group and as individuals, which allows at least some oligarchs to enhance their reputation by using their vast material wealth. I conclude this thesis by discussing possible policy and societal implication of the results and by setting out some new venues of future research.
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| 34. |
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| 35. |
- Baiocchi, B., et al.
(författare)
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Transport analysis and modelling of the evolution of hollow density profiles plasmas in JET and implication for ITER
- 2015
-
Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 55:12
-
Tidskriftsartikel (refereegranskat)abstract
- The density evolution during the transient phase just after the L-H transition is investigated using theoretical transport models. Cases characterized by core densities which evolve in longer timescales than the edge densities, leading to hollow density profiles (R/L-n = -R del n/n < 0) are modelled. This density evolution is particularly interesting because it has been shown to be beneficial in the view of the access to burning plasma conditions in ITER (Loarte et al 2013 Nucl. Fusion 53 083031). Self-consistent simulations of the JET discharge 79676 of the density-only, and of the density and the temperatures are carried out using a quasilinear gyrokinetic code, QuaLiKiz (Bourdelle et al 2007 Phys. Plasmas 14 112501), coupled with a transport code CRONOS (Artaud et al 2010 Nucl. Fusion 50 043001). The slow evolution of the hollow density, associated with the self-consistently calculated hollow NBI particle deposition, is well reproduced in the plasma core. Indeed, QuaLiKiz is shown to reproduce nonlinear gyrokinetic heat and particle fluxes well for both positive and negative R/L-n. That gives a theoretical and general basis for the persistence of the hollowness, laying the groundwork for the extrapolation to ITER.
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| 36. |
- Baiocchi, B., et al.
(författare)
-
Turbulent transport analysis of JET H-mode and hybrid plasmas using QuaLiKiz and Trapped Gyro Landau Fluid
- 2015
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 57:3
-
Tidskriftsartikel (refereegranskat)abstract
- The physical transport processes at the basis of JET typical inductive H-mode scenarios and advanced hybrid regimes, with improved thermal confinement, are analyzed by means of some of the newest and more sophisticated quasi-linear transport models: trapped gyro Landau fluid (TGLF) and QuaLiKiz. The temporal evolution of JET pulses is modelled by CRONOS where the turbulent transport is modelled by either QuaLiKiz or TGLF. Both are first principle models with a more comprehensive physics than the models previously developed and therefore allow the analysis of the physics at the basis of the investigated scenarios. For H-modes, ion temperature gradient (ITG) modes are found to be dominant and the transport models are able to properly reproduce temperature profiles in self-consistent simulations. However, for hybrid regimes, in addition to ITG trapped electron modes (TEM) are also found to be important and different physical mechanisms for turbulence reduction play a decisive role. Whereas E x B flow shear and plasma geometry have a limited impact on turbulence, the presence of a large population of fast ions, quite important in low density regimes, can stabilize core turbulence mainly when the electromagnetic effects are taken into account. The TGLF transport model properly captures these mechanisms and correctly reproduces temperatures.
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| 37. |
- Baron-Wiechec, A., et al.
(författare)
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Thermal desorption spectrometry of beryllium plasma facing tiles exposed in the JET tokamak
- 2018
-
Ingår i: Fusion engineering and design. - : ELSEVIER SCIENCE SA. - 0920-3796 .- 1873-7196. ; 133, s. 135-141
-
Tidskriftsartikel (refereegranskat)abstract
- The phenomena of retention and de-trapping of deuterium (D) and tritium (T) in plasma facing components (PFC) and supporting structures must be understood in order to limit or control total T inventory in larger future fusion devices such as ITER, DEMO and commercial machines. The goal of this paper is to present details of the thermal desorption spectrometry (TDS) system applied in total fuel retention assessment of PFC at the Joint European Torus (JET). Examples of TDS results from beryllium (Be) wall tile samples exposed to JET plasma in PFC configuration mirroring the planned ITER PFC is shown for the first time. The method for quantifying D by comparison of results from a sample of known D content was confirmed acceptable. The D inventory calculations obtained from Ion Beam Analysis (IBA) and TDS agree well within an error associated with the extrapolation from very few data points to a large surface area.
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| 38. |
- Basiuk, V., et al.
(författare)
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Towards self-consistent plasma modelisation in presence of neoclassical tearing mode and sawteeth : effects on transport coefficients
- 2017
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 59:12
-
Tidskriftsartikel (refereegranskat)abstract
- The neoclassical tearing modes (NTM) increase the effective heat and particle radial transport inside the plasma, leading to a flattening of the electron and ion temperature and density profiles at a given location depending on the safety factor q rational surface (Hegna and Callen 1997 Phys. Plasmas 4 2940). In burning plasma such as in ITER, this NTM-induced increased transport could reduce significantly the fusion performance and even lead to a disruption. Validating models describing the NTM-induced transport in present experiment is thus important to help quantifying this effect on future devices. In this work, we apply an NTM model to an integrated simulation of current, heat and particle transport on JET discharges using the European transport simulator. In this model, the heat and particle radial transport coefficients are modified by a Gaussian function locally centered at the NTM position and characterized by a full width proportional to the island size through a constant parameter adapted to obtain the best simulations of experimental profiles. In the simulation, the NTM model is turned on at the same time as the mode is triggered in the experiment. The island evolution is itself determined by the modified Rutherford equation, using self-consistent plasma parameters determined by the transport evolution. The achieved simulation reproduces the experimental measurements within the error bars, before and during the NTM. A small discrepancy is observed on the radial location of the island due to a shift of the position of the computed q = 3/2 surface compared to the experimental one. To explain such small shift (up to about 12% with respect to the position observed from the experimental electron temperature profiles), sensitivity studies of the NTM location as a function of the initialization parameters are presented. First results validate both the transport model and the transport modification calculated by the NTM model.
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| 39. |
- Batistoni, P., et al.
(författare)
-
Overview of neutron measurements in jet fusion device
- 2018
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Ingår i: Radiation Protection Dosimetry. - : OXFORD UNIV PRESS. - 0144-8420 .- 1742-3406. ; 180:1-4, s. 102-108
-
Tidskriftsartikel (refereegranskat)abstract
- The design and operation of ITER experimental fusion reactor requires the development of neutron measurement techniques and numerical tools to derive the fusion power and the radiation field in the device and in the surrounding areas. Nuclear analyses provide essential input to the conceptual design, optimisation, engineering and safety case in ITER and power plant studies. The required radiation transport calculations are extremely challenging because of the large physical extent of the reactor plant, the complexity of the geometry, and the combination of deep penetration and streaming paths. This article reports the experimental activities which are carried-out at JET to validate the neutronics measurements methods and numerical tools used in ITER and power plant design. A new deuterium-tritium campaign is proposed in 2019 at JET: the unique 14 MeV neutron yields produced will be exploited as much as possible to validate measurement techniques, codes, procedures and data currently used in ITER design thus reducing the related uncertainties and the associated risks in the machine operation.
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| 40. |
- Batistoni, P., et al.
(författare)
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Technical preparations for the in-vessel 14 MeV neutron calibration at JET
- 2017
-
Ingår i: Fusion engineering and design. - : ELSEVIER SCIENCE SA. - 0920-3796 .- 1873-7196. ; 117, s. 107-114
-
Tidskriftsartikel (refereegranskat)abstract
- The power output of fusion devices is measured from their neutron yields which relate directly to the fusion yield. In this paper we describe the devices and methods that have been prepared to perform a new in situ 14 MeV neutron calibration at JET in view of the new DT campaign planned at JET in the next years. The target accuracy of this calibration is 10% as required for ITER, where a precise neutron yield measurement is important, e.g., for tritium accountancy. In this paper, the constraints and early decisions which defined the main calibration approach are discussed, e.g., the choice of 14 MeV neutron source and the deployment method. The physics preparations, source issues, safety and engineering aspects required to calibrate directly the JET neutron detectors are also discussed. The existing JET remote-handling system will be used to deploy the neutron source inside the JET vessel. For this purpose, compatible tooling and systems necessary to ensure safe and efficient deployment have been developed. The scientific programme of the preparatory phase is devoted to fully characterizing the selected 14 MeV neutron generator to be used as the calibrating source, obtain a better understanding of the limitations of the calibration, optimise the measurements and other provisions, and to provide corrections for perturbing factors (e.g., anisotropy of the neutron generator, neutron energy spectrum dependence on emission angle). Much of this work has been based on an extensive programme of Monte-Carlo calculations which provide support and guidance in developing the calibration strategy.
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| 41. |
- Beal, J., et al.
(författare)
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Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall
- 2016
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Ingår i: Physica Scripta. - : IOP PUBLISHING LTD. - 0031-8949 .- 1402-4896. ; T167
-
Tidskriftsartikel (refereegranskat)abstract
- Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used to investigate erosion/deposition during JET-C carbon operation and JET-ILW (ITER-like wall) beryllium/tungsten operation. A simple geometrical model utilising experimental data is used to model the time-dependent collector deposition profiles, demonstrating good qualitative agreement with experimental results. Overall, the JET-ILW collector deposition is reduced by an order of magnitude relative to JET-C, with beryllium replacing carbon as the dominant deposit. However, contrary to JET-C, in JET-ILW there is more deposition on the outer collector than the inner. This reversal of deposition asymmetry is investigated using an analysis of QMB data and is attributed to the different chemical properties of carbon and beryllium.
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| 42. |
- Bellander, Henrik, 1978-
(författare)
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Rättegångskostnader : Om kostnadsbördan i dispositiva tvistemål
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rättegångskostnader – Costs in Civil ProcedureThe rules on costs in Chapter 18 of the Swedish Code of Legal Procedure (Sw: Rättegångsbalken) have an impact on several procedural questions but have rarely been thoroughly discussed in legal practice or theory since their adoption in 1942. On the other hand, since the Code was adopted civil procecedure scholars have considerably focused on the development and changes in society and how they affect civil procedure.This thesis aims at examining both these lines of development. The impact of the theoretical discussions during the 20th century is critically addressed, with special attention to cost-related questions, and the application of rules on costs in some current and actual situations are examined and evaluated from a pragmatic perspective.The inquiry shows that costs have been of indirect relevance for the theoretical discussion in procedural law and that this theoretical development in turn has had effects on cost rules. Changing views on civil procedure have led to altered framings of cost problems and to shifts in how the rules have been comprehended and applied. The inquiry covers questions on cost assessment and cost shifting between the parties, as well as problems connected to possibilities to spread costs and risk on legal representatives, funders and others.It is argued that a more compromising and pluralistic application of the rules combined with more explicit communication in cost issues between the parties and the court during early stages of the proceedings may facilitate and lead to more nuanced cost decisions without burdening the final stages of the proceedings with extensive legal argumentation.
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| 43. |
- Berglund, Martina, et al.
(författare)
-
Understanding the user beyond ‘common sense’ – teaching Product Ergonomics to design engineering students
- 2015
-
Ingår i: Proceedings 19th Triennial Congress of the IEA. - : International Ergonomics Association.
-
Konferensbidrag (refereegranskat)abstract
- Multidisciplinary frameworks are needed to develop products that fit the human. Ergonomics is a multifaceted field that encompasses physical, cognitive and organizational aspects, and it is therefore a suitable subject to be taught to design engineering students.The objective of this paper was to describe and reflect upon how a systems perspective on Ergonomics is developed and conveyed in a course in Product Ergonomics to engineering students at the Design and Product Development (DPD) programme at Linköping University, Sweden. The paper is based on the authors’ experiences from teaching the course in Product Ergonomicsas well ason 52 students’ written reflections about their view on Ergonomics before and after taking the course.Means and ideas for teaching Ergonomics with a systems perspective included organizing a theoretical introduction into weekly themes and thereafter integrating and applying these themes in a product concept project under supervision of a multidisciplinary teacher team.The paper also reflects on how the systems perspective of Ergonomics is planned for and realized in the intended, implemented and attained curriculum.
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| 44. |
- Bergsåker, Henric, et al.
(författare)
-
Assessment of the strength of kinetic effects of parallel electron transport in the SOL and divertor of JET high radiative H-mode plasmas using EDGE2D-EIRENE and KIPP codes
- 2018
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 60:11
-
Tidskriftsartikel (refereegranskat)abstract
- The kinetic code for plasma periphery (KIPP) was used to assess the importance of the kinetic effects of parallel electron transport in the scrape-off layer (SOL) and divertor of JET high radiative H-mode inter-ELM plasma conditions with the ITER-like wall and strong nitrogen (N-2) injection. Plasma parameter profiles along a magnetic field from one of the EDGE2D-EIRENE simulation cases were used as an input for KIPP runs. Profiles were maintained by particle and power sources. KIPP generated electron distribution functions, f(e), parallel power fluxes, electron-ion thermoforces, Debye sheath potential drops and electron sheath transmission factors at divertor targets. For heat fluxes in the main SOL, KIPP results showed deviations from classical (e.g. Braginskii) fluxes by factors typically of similar to 1.5, sometimes up to 2, with the flux limiting for more upstream positions and flux enhancement near entrances to the divertor. In the divertor, at the same time, for radial positions closer to the separatrix, very large heat flux enhancement factors of up to ten or even higher, indicative of a strong nonlocal heat transport, were found at the outer target, with heat power flux density exhibiting bump-on-tail features at high energies. Under such extreme conditions, however, contributions of conductive power fluxes to total power fluxes were strongly reduced, with convective power fluxes becoming comparable, or sometimes exceeding, conductive power fluxes. Electron-ion thermoforce, on the other hand, which is known to be determined mostly by thermal and subthermal electrons, was found to be in good agreement with Braginskii formulas, including the Z(eff) dependence. Overall, KIPP results indicate, at least for the plasma conditions used in this modelling, a sizable, but not dominant, effect of kinetics on parallel electron transport.
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| 45. |
- Bernardo, J., et al.
(författare)
-
Ion temperature and toroidal rotation in JET's low torque plasmas
- 2016
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 87:11
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the procedure developed as the best method to provide an accurate and reliable estimation of the ion temperature T-i and the toroidal velocity v(phi) from Charge-eXchange Recombination Spectroscopy (CXRS) data from intrinsic rotation experiments at the Joint European Torus with the carbon wall. The low impurity content observed in such plasmas, resulting in low active CXRS signal, alongside low Doppler shifts makes the determination of Ti and v(phi) particularly difficult. The beam modulation method will be discussed along with the measures taken to increase photon statistics and minimise errors from the absolute calibration and magneto-hydro-dynamics effects that may impact the CXRS passive emission.
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| 46. |
- Bernert, M., et al.
(författare)
-
Power exhaust by SOL and pedestal radiation at ASDEX Upgrade and JET
- 2017
-
Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 12, s. 111-118
-
Tidskriftsartikel (refereegranskat)abstract
- Future fusion reactors require a safe, steady state divertor operation. A possible solution for the power exhaust challenge is the detached divertor operation in scenarios with high radiated power fractions. The radiation can be increased by seeding impurities, such as N for dominant scrape-off-layer radiation, Ne or Ar for SOL and pedestal radiation and Kr for dominant core radiation. Recent experiments on two of the all-metal tokamaks, ASDEX Upgrade (AUG) and JET, demonstrate operation with high radiated power fractions and a fully-detached divertor by N, Ne or Kr seeding with a conventional divertor in a vertical target geometry. For both devices similar observations can be made. In the scenarios with the highest radiated power fraction, the dominant radiation originates from the confined region, in the case of N and Ne seeding concentrated in a region close to the X-point. Applying these seed impurities for highly radiative scenarios impacts local plasma parameters and alters the impurity transport in the pedestal region. Thus, plasma confinement and stability can be affected. A proper understanding of the effects by these impurities is required in order to predict the applicability of such scenarios for future devices.
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| 47. |
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| 48. |
- Binda, Federico, 1987-, et al.
(författare)
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Calculation of the profile-dependent neutron backscatter matrix for the JET neutron camera system
- 2017
-
Ingår i: Fusion engineering and design. - : ELSEVIER SCIENCE SA. - 0920-3796 .- 1873-7196. ; 123, s. 865-868
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the dependence of the backscatter component of the neutron spectrum on the emissivity profile. We did so for the JET neutron camera system, by calculating a profile-dependent backscatter matrix for each of the 19 camera channels using a MCNP model of the JET tokamak. We found that, when using a low minimum energy for the summation of the counts in the neutron pulse height spectrum, the backscatter contribution can depend significantly on the emissivity profile. The maximum variation in the backscatter level was 24% (8.0% when compared to the total emission). This effect needs to be considered when a correction for the backscatter contribution is applied to the measured profile. (C) 2017 The Authors. Published by Elsevier B.V.
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| 49. |
- Binda, Federico, 1987-, et al.
(författare)
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Generation of the neutron response function of an NE213 scintillator for fusion applications
- 2017
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : ELSEVIER. - 0168-9002 .- 1872-9576. ; 866, s. 222-229
-
Tidskriftsartikel (refereegranskat)abstract
- In this work we present a method to evaluate the neutron response function of an NE213 liquid scintillator. This method is particularly useful when the proton light yield function of the detector has not been measured, since it is based on a proton light yield function taken from literature, MCNPX simulations, measurements of gammarays from a calibration source and measurements of neutrons from fusion experiments with ohmic plasmas. The inclusion of the latter improves the description of the proton light yield function in the energy range of interest (around 2.46 MeV). We apply this method to an NE213 detector installed at JET, inside the radiation shielding of the magnetic proton recoil (MPRu) spectrometer, and present the results from the calibration along with some examples of application of the response function to perform neutron emission spectroscopy (NES) of fusion plasmas. We also investigate how the choice of the proton light yield function affects the NES analysis, finding that the result does not change significantly. This points to the fact that the method for the evaluation of the neutron response function is robust and gives reliable results. (C) 2017 Published by Elsevier B.V.
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| 50. |
- Bisoffi, Andrea, et al.
(författare)
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Hybrid cancellation of ripple disturbances arising in AC/DC converters
- 2017
-
Ingår i: Automatica. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0005-1098 .- 1873-2836. ; 77, s. 344-352
-
Tidskriftsartikel (refereegranskat)abstract
- In AC/DC converters, a peculiar periodic nonsmooth waveform arises, the so-called ripple. In this paper we propose a novel model that captures this nonsmoothness by means of a hybrid dynamical system performing state jumps at certain switching instants, and we illustrate its properties with reference to a three phase diode bridge rectifier. As the ripple corrupts an underlying desirable signal, we propound two observer schemes ensuring asymptotic estimation of the ripple, the first with and the second without knowledge of the switching instants. Our theoretical developments are well placed in the context of recent techniques for hybrid regulation and constitute a contribution especially for our second observer, where the switching instants are estimated. Once asymptotic estimation of the ripple is achieved, the ripple can be conveniently canceled from the desirable signal, and thanks to the inherent robustness properties of the proposed hybrid formulation, the two observer schemes require only that the desirable signal is slowly time varying compared to the ripple. Exploiting this fact, we illustrate the effectiveness of our second hybrid observation law on experimental data collected from the Joint European Torus tokamak.
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