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A method for comparing the levelized cost of energy (LCoE) of different superconducting drive trains is introduced. The properties of a 10-MW MgB2 superconducting direct-drive generator and the cost break down of the nacelle components are presented and scaled up to a turbine with a rotor diameter of up to 280 m. The partial load efficiency of the generator is evaluated for a constant cooling power of 0, 50, and 100 kW, and the annual energy production is used to determine the impact on the LCoE., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses theDutch legislation to make this work public., DC systems, Energy conversion & Storage, Transport Engineering and Logistics

A method for comparing the Levelized Cost of Energy (LCoE) of different superconducting drive trains is introduced. The properties of a 10 MW MgB$_{2}$ superconducting direct drive generator are presented in terms weight scaled to a turbine with a rotor diameter up of 280 m and the cost break down of the nacelle components. The partial load efficiency of the generator is evaluated for a constant cooling power of 0, 50 kW and 100 kW and the annual energy production is used to determine the impact on Levelized Cost of Energy.

Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight, and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in full-scale generators, tests of different winding methodologies and techniques are needed. In this paper, we describe in detail the steps used to wind a racetrack coil with a length of 1 m and a width of 0.5 m out of 4.5 km of MgB2 superconducting tape. The width corresponds to a full-scale pole of a 10-MW generator, whereas the length of the straight section is shorter than the corresponding full-scale pole. The coil was built up of ten double pancake coils. Each double pancake coil was wet wound using a semiautomatic winding process, where Stycast 2850 was applied directly to the MgB2 tape without any other dedicated electrical insulation. The strengths and weaknesses of the winding process are discussed and compared to the dry-winding method.

Innovative drive trains targeted at 10-20 MW offshore turbines are investigated in the INNWIND.EU project in order to determine the impact on the Levelized Cost of Energy (LCoE) resulting when installed in the ,North sea at 50 m of water [1]. The two main technologies studied are superconducting direct drive (SCDD)[2] and the magnetic pseudo direct drive (PDD) [3] generators, which are both capable to providing compact drive trains with low weight and a small number of moving parts compared to a gearbox based drive train (see figure 1a). Superconducting field coils are used to provide the torque in the direct drive generators, where the armature windings are based on conventional copper wire and magnetic steel laminates operated at ambient temperature. Magnetic pseudo direct drive generators consist of a magnetic gearbox made of an inner free rotor (rotating at a geared up speed to the blade input) and an intermediate drive rotor inserted into an outer static armature winding, where the electricity is harvested., DC systems, Energy conversion & Storage

Gaseller kallas företag som växer i en enormt snabb takt. Det finns idag ingen allmänt vedertagen definition av vad ett gasellföretag är, men vanligtvis brukar man inom forskningen säga att ett gasellföretag har en säljökning med minst 20 % per år i 2-5 år. Trots att dessa företag endast utgör 2-10 % av alla små och medelstora företag fast de endast utgör en så liten del så utgör det till mer än 40 % av alla nya jobb som skapas på arbetsmarknaden. Problematiken för dessa företag som kallas för gaseller är att en stor del av dessa företag inte har någon längre livscykel. Lika snabbt som de kommer in på marknaden lika snabbt försvinner de igen. Skillnaden mellan företagen är dock stor och vissa lyckas mycket bättre än andra.Just det faktum att vissa gasellföretag lyckas så mycket bättre än andra är en intressant sak att undersöka. I denna studie undersöks om det kan vara så att ett företags strategiska val kan påverka ett gasellföretags möjlighet att utvecklas och förbli ett gasellföretag och i så fall på vilket sätt det kan påverka. Studien tar sin utgångspunkt i Mintzbergs (1993) superstruktur och använder sig även av de tankar och idéer som Markiewicz (2011) har utvecklat angående barriärer som kan tänkas finnas vid ett strategiimplementerande i organisationer.Studiens syfte att undersöka hur ett företags strategival påverkar dess möjlighet att utvecklas och förbli ett gasellföretag har fordrat en kvalitativ metod. Därför bygger det empirska materialet på observationer på det utvalda företaget samt intervjuer med personer på de olika nivåerna i företaget.Uppsatsen visar hur ett speciellt företag som har en brant tillväxtkurva som ett gasellföretag agerar för att på ett så bra sätt som möjligt implementera en strategi som ska göra det möjligt för företaget att förbli ett gasellföretag. Mintzbergs (1993) superstruktur och Markiewicz (2011) fyra barriärer angående strategiimplementering i organisationer har varit det teoretiska stödet i uppsatsen., Gazelles are companies which have an annual increase in sales of at least 20 %, for a running period of 2 to 5 years. Despite all this these companies only stands for 2-10 % of the entire market of small to medium sized business. Despite this small number they are accounted for more than 40 % of all the new jobs who are created. The problem these companies are experiencing is that their lifecycle are short. As fast as they enter the market they disappear. The differences between the companies are large and some of them succeed better than the others.The fact that some gazelles do better than others is an interesting subject to investigate. This study investigates if a company’s strategic decisions may affect it´s possibilities to evolve into a gazelle company and how it does it. The study has its base in Mintzbergs (1993) superstructure and it uses the thoughts and ideas of Markiewicz (2011) resolving around his implementation barriers.The purpose of this study is to investigate how a company´s strategic choice affects their capability of sustaining the levels required to be called gazelles, this have steered the study in the direction of a qualitative study. That is why the empirical studies are built up from observations and interviews with individuals from different hierarchical levels.This essay shows how a specific gazelle company acts to implement strategies to make sure that they will remain a gazelle. Mintzbergs (1993) superstructure and Markiewicz (2011) four barriers regarding strategy implementation has been the theoretical support in the essay.The essay itself is written in Swedish.

Purpose: The aim of the present study was to assess the outcome results after reoperation for persistent pain after hernia surgery in a population-based setting. Methods: All patients who had undergone surgery for persistent pain after previous groin hernia surgery 1999-2006 were identified in the Swedish Hernia Register (n = 237). Data on the surgical technique used were abstracted from the medical records. The patients were asked to answer a set of questions including SF-36 to evaluate the prevalence of pain after reoperation. Results: The study group consisted of 95 males and 16 females, mean age 53 years. In 27 % of cases an intervention aimed at suspected ilioinguinal neuralgia was performed. The mesh was removed completely in 28 % and partially in 13 %. A suture at the pubic tubercle was removed in 13 % of cases. Decrease in pain after the most recent reoperation was reported by 69 patients (62 %), no change in pain by 21 patients (19 %) and increase in pain in 21 patients (19 %). There was no significant difference in outcome between mesh removal, removal of sutures at the tubercle or interventions aimed at the ilioinguinal nerve. All subscales of SF-36 were significantly reduced when compared to the age-and gender-matched general population (p < 0.05). Conclusions: Patients reoperated for persistent pain after hernia surgery often report a reduction in pain, but the natural course of persistent pain, the relatively low response rate and selection of patients make it difficult to draw definite conclusions., Funding Agencies:Center for Clinical Research, Dalarna, SwedenOlle Engqvist research foundation

Topologies of superconducting direct drive wind turbine generators are based on a combination of superconducting wires wound into field coils, copper armature windings, steel laminates to shape the magnetic flux density and finally structural materials as support. But what is the most optimal topology for superconducting wind turbine generators? This question is investigated by assuming some unit cost of the different materials and then minimizing the cost of the active materials of a 10 MW and 9.65 rpm direct drive wind turbine generator intended to be mounted in front of the INNWIND.EU King-Pin concept nacelle. A series of topologies are investigate by adding more iron components to the generator, such as rotor back iron, field winding pole, magnetic teeth and armature back iron. This method is used to investigate 6 topologies and to determine the optimal cost of the different topologies by using the current cost of 4 €/m for the MgB2 wire from Columbus Superconductors and also a possible future cost of 1 €/m if a superconducting offshore wind power capacity of 10 GW has been introduced by 2030 as suggested in a roadmap. The obtained topologies are compared to what is expected from a permanent magnet direct drive generators and the further development directions are discussed. Finally an experimental INNWIND.EU demonstration showing that the current commercial MgB2 wires can be wound into functional field coils for wind turbine generators is discussed.

An MgB2 race track coil intended for demonstrating a down scaled pole of a 10 MW direct drive wind turbine generator has been designed. The coil consists of 10 double pancake coils stacked into a race track coil with a cross section of 84 mm × 80 mm. The length of the straight section is 0.5 m and the diameter of the end sections is 0.3 m. Expanded to a straight section of 3.1 m it will produce about 1.5 T magnetic flux density in the air gap of the 10 MW 32 pole generator and about 3.0 T at the edge of the superconducting coil with an operation current density of the coil of 70 A/mm2.

BACKGROUND: Post-operative pain and nausea may be a problem in day-case surgery. This study aims to investigate the effect of betamethasone on pain and nausea in inguinal hernia surgery. METHODS: Patients aged 18-70 years scheduled for open inguinal hernia surgery at two Swedish hospitals, March 2005-December 2009, were eligible for inclusion. Patients were randomized, to either treatment with 12 mg betamethasone intravenously or placebo. Post-operative pain was assessed using a visual analogue scale on the recovery ward, each day the first post-operative week and at 1 month after surgery. One year after surgery, residual pain was estimated by the Inguinal Pain Questionnaire. RESULTS: A total of 398 patients were included (21 women, 377 men). Pain at rest on the day of surgery was significantly lower in the treatment group (p = 0.012). The pain was also significantly lower in the treatment group the day after surgery (p < 0.001), but not during the remaining part of the first post-operative week. Bleeding complications were reported by 17 patients (8.5%) in the Betamethasone group and seven (3.5%) in the placebo group (p = 0.028). One month after surgery, 21 out of 173 (12%) in the betamethasone group still had pain, compared to 33 out of 159 (21%) in the placebo arm (p = 0.049). After 1 year, no significant difference in pain was seen. CONCLUSION: A 12 mg betamethasone reduced pain during the first 24 h and at 1 month after inguinal hernia surgery. If combined with diclofenac, however, this dose may increase the risk for bleeding complications., This study was supported by research grants from the county council of Dalarna and the county council of Örebro, Sweden.Ingår i avhandling: Magnusson, Niklas. Postoperative aspects of inguinal hernia surgery: pain and recurrences. 2012.

PURPOSE: If the pathogeneses of the development of a recurrence varies following the different methods of hernia repair, the time required to develop a recurrence could be expected to vary. The aim of the study was to identify risk factors affecting the time interval between the primary repair and the reoperation. METHODS: Data from the Swedish Hernia Register were used. Each year of the 5-year follow-up period was treated as a separate subgroup and merged together into one large group. For each risk factor, we performed a Cox proportional hazard analysis, testing for interactions between the year and the risk factor, with reoperation as the endpoint. RESULTS: Altogether, 142,578 repairs were recorded, of which 7.7% were performed on women. The mean age of the cohort was 59 years. The overall recurrence rate in the 5-year period was 4.3%. Multivariate analysis showed that recurrence following surgery for recurrent hernia occurred relatively early (P < 0.05).Recurrence also appeared early if postoperative complications were registered (P < 0.05). Recurrence after suture repair or laparoscopic repair appeared relatively early compared to recurrence following open mesh repair (P < 0.05). In a separate analysis, a relatively higher risk for early recurrence was seen for all sutured repairs compared to all mesh repairs (P < 0.05). CONCLUSIONS: The pathogenesis behind the development of recurrence probably differs depending on the technique applied during the hernia repair. The higher proportion of early recurrences following laparoscopic repair, suture repair and recurrent repair may be explained by the high proportion of technical failures.

AC losses are of great importance when designing devices for electric power applications based on high-temperature superconducting (HTS) tapes. In order to obtain an optimized design one needs to be able to calculate the AC losses that appear in an actual application. One important quantity is the AC losses that appear at the ends of a coil where the magnetic field contains a component perpendicular to the face of the tape. In this study we calculate the AC losses due to the combined action of a perpendicular magnetic field and a transport current. The results are compared to calorimetrically measured data of the AC losses in a BSCCO/Ag HTS tape.

When high-temperature superconducting tapes are used in electrotechnical applications, they have an optimal working point in temperature. In the winding of e.g. a transformer the conductor carrying an AC current is exposed to an AC magnetic field oriented differently in separate parts of the winding. To determine the optimal working temperature it is essential to study the temperature dependence of the AC losses under these conditions. In this study, we present experimental results of the losses in a multi-filamentary silver-sheathed Bi-2223 high-temperature superconducting tape carrying an AC transport current in an AC magnetic field applied in different orientations perpendicular to the current path. The losses were measured calorimetrically in the temperature interval 40-85 K. The experimental results are compared to semi-empirical models of the AC losses., 5th European Conference on Applied Superconductivity (EUCAS 2001) Location: TECH UNIV DENMARK, LYNGBY, DENMARK Date: AUG 26-30, 2001

QC 20111117