| 1. |
- Jarvid, Markus, 1985, et al.
(författare)
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A New Application Area for Fullerenes: Voltage Stabilizers for Power Cable Insulation
- 2015
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 27:5, s. 897-902
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Tidskriftsartikel (refereegranskat)abstract
- Fullerenes are shown to be efficient voltage-stabilizers for polyethylene, i.e., additives that increase the dielectric strength of the insulation material. Such compounds are highly sought-after because their use in power-cable insulation may considerably enhance the transmission efficiency of tomorrow's power grids. On a molal basis, fullerenes are the most efficient voltage stabilizers reported to date.
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| 2. |
- Jarvid, Markus, 1985, et al.
(författare)
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High electron affinity: a guiding criterion for voltage stabilizer design
- 2015
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 3:14, s. 7273-7286
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Tidskriftsartikel (refereegranskat)abstract
- Voltage stabilizers are an emerging class of additives that enhance the dielectric strength of an insulating polymer such as polyethylene. Several partially conflicting reports ascribe the stabilizing effect to either a high electron affinity or low ionization potential of the additive. Here, we report a clear correlation of the electron affinity and to a lesser extent the EHOMO–ELUMO difference of various voltage stabilizers with electrical tree initiation in cross-linked polyethylene. To facilitate a fair evaluation, the voltage-stabilizing efficiency of a set of 13 previously reported voltage stabilizers, which strongly differ in their chemical composition, is compared at equal stabilizer concentration and equivalent test methodology. These results are correlated with the electron affinity and EHOMO–ELUMO difference, as obtained from density functional theory (DFT) modeling, which agreed well with available literature values. Moreover, based on the here established strong correlation between dielectric strength and electron affinity, a new molecule with exceptionally high electron affinity is selected from the extended literature on organic photovoltaics. This malononitrile–benzothiadiazole–triarylamine based molecule with a high electron affinity of 3.4 eV gives rise to a 148% increase in tree initiation field compared to 40% obtained using anthracene, one of the most efficient previously reported voltage-stabilizers, under equivalent test conditions. Thus, we here propose to use the electron affinity as a guiding criterion for identifying novel high-efficiency voltage stabilizers, which opens up the vast library of organic semiconductors as potential candidates, as well as associated synthesis routines for the design of yet unexplored materials.
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| 3. |
- Wutzel, Harald, 1976, et al.
(författare)
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Thioxanthone Derivatives as Stabilizers Against Electrical Breakdown in Cross-Linked Polyethylene for High Voltage Cable Applications
- 2015
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Ingår i: Polymer Degradation and Stability. - : Elsevier BV. - 0141-3910. ; 112, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- In the search of voltage stabilizers for high voltage underground cables the chemical synthesis and electrical tree inhibiting effect of a series of thioxanthone derivatives in cross-linked low-density polyethylene (XLPE) is reported. The strongest increase in electrical tree initiation field under high-voltage alternating current (HVAC) conditions was 55% compared to reference XLPE after the addition of 0.3 wt% 9-oxo-9H-thioxanthen-2-yl methacrylate. Thermal analysis, small angle X-ray scattering and gel content measurements showed that the addition of the stabilizers did not significantly influence the microstructure and gel fraction of XLPE. A comparison between the stabilizing effects of the thioxanthone derivatives and previously reported photophysical properties revealed that a short lifetime of the triplet excited state can be related to a good voltage-stabilizing effect.
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| 4. |
- Andersson, Mattias, 1985, et al.
(författare)
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Dielectric strength of γ-radiation cross-linked, high vinyl-content polyethylene
- 2015
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Ingår i: European Polymer Journal. - : Elsevier BV. - 0014-3057. ; 64, s. 101-107
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Tidskriftsartikel (refereegranskat)abstract
- We explore γ-radiation cross-linking of high vinyl-content low-density polyethylene (LDPE) and its potential use as a high-voltage insulation material. Of the three investigated resins containing 1, 0.5 and 0.17 vinyl groups per 1000 carbons, respectively, only the highest vinyl-content material featured a sufficiently high gel content of more than 70% and hot-set elongation below 175%, when cross-linked with a γ-radiation dose of at least 68 kGy. Differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) reveal that neither the crystallinity nor the lamellar thickness of the highest vinyl-content LDPE are negatively affected by γ-radiation cross-linking. As a result, we find that the dielectric strength, as characterized by electrical tree initiation experiments, can be maintained upon γ-radiation cross-linking.
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| 5. |
- Börve, Alexander, et al.
(författare)
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Smartphone Teledermoscopy Referrals: A Novel Process for Improved Triage of Skin Cancer Patients.
- 2015
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Ingår i: Acta dermato-venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 95:2, s. 186-190
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Tidskriftsartikel (refereegranskat)abstract
- In this open, controlled, multicentre and prospective observational study, smartphone teledermoscopy referrals were sent from 20 primary healthcare centres to 2 dermatology departments for triage of skin lesions of concern using a smartphone application and a compatible digital dermoscope. The outcome for 816 patients referred via smartphone teledermoscopy was compared with 746 patients referred via the traditional paper-based system. When surgical treatment was required, the waiting time was significantly shorter using teledermoscopy for patients with melanoma, melanoma in situ, squamous cell carcinoma, squamous cell carcinoma in situ and basal cell carcinoma. Triage decisions were also more reliable with teledermoscopy and over 40% of the teledermoscopy patients could potentially have avoided face-to-face visits. Only 4 teledermoscopy referrals (0.4%) had to be excluded due to poor image quality. Smartphone teledermoscopy referrals allow for faster and more efficient management of patients with skin cancer as compared to traditional paper referrals.
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| 6. |
- Ellonen, Hanna-Kaisa, et al.
(författare)
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Magazine management : Publishing as a business
- 2015
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Ingår i: The Routledge Handbook of Magazine Research. - New York : Routledge. - 9781138854161
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Bokkapitel (refereegranskat)abstract
- Magazine management as a field of study lies within the area of Media Management and Economics (MME). MME research is producing a growing body of literature focusing on economic, management and business issues in the media industries, based largely on traditional concepts and theories in the two related disciplines of management and economics. Study of media management and economics has grown in stature since the 1990s pioneering works of Robert Picard and Alan Albarran. Several seminal books have been published in the 2000s, including the Handbook of Media Management and Economics and Annet Aris and Jacques Bughin’s Managing Media Companies. The founding of three academic journals, namely the Journal of Media Economics (in 1988), the International Journal of Media Management (in 1999), and the Journal of Media Business Studies (in 2007), has established the field by providing industry-specific publication outlets for research on journalism and media-based business and economics.This chapter comprises a review of the current research on the magazine industry, segmented in the following five categories: media economics, management research, business modeling, innovation and brand management. These categories reflect the main body of research related to magazines and magazine publishing from a business perspective. Research specific to magazine publishing is scarce in comparison with that in other media sectors, such as the newspaper industry. However, a strength is that the body of magazine-related research includes both global and digital studies, with theory and applications continuing to mature. Included in this review is management research that focuses on magazine publishers, as well as research in which magazine publishing is the empirical context for a larger theoretical approach.
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| 7. |
- Ellonen, Hanna-Kaisa, et al.
(författare)
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The interplay of dominant logic and dynamic capabilities in innovation activities
- 2015
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Ingår i: International Journal of Innovation Management. - : Imperial College Press. - 1363-9196 .- 1757-5877. ; 19:5, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Within the strategic management literature, both managerial cognition and dynamic capabilities have been identified as drivers of change and transition in changing business environments. The purpose of this study is to explore the interplay of dominant logic and dynamic capabilities in the magazine publishing industry. We investigated four magazine publishing business units of a large media corporation situated in four different countries, namely Finland, the Netherlands, Hungary and Russia. A total of 40 magazine managers were interviewed. The results imply that dominant logic and dynamic capabilities coevolve in a reciprocal relationship, and the interplay of cognition and capabilities seems to be most visible in the seizing and reconfiguring capabilities. The results of the present study also illustrate that there may be several contradictory dominant logics within a single company. Dynamic capabilities useful to innovation processes are developed in the areas that are pinpointed by the managers as the locus of attention. Industry transition does not automatically change what companies think and do. That requires managerial attention and an active reconceptualization of the business and active development of not only day-to-day operations, but capabilities needed to change the way we work.
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| 8. |
- Ellonen, Hanna-Kaisa, et al.
(författare)
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The role of the website in a magazine business – revisiting old truths
- 2015
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Ingår i: Journal of Media Business Studies. - : Taylor & Francis Group. - 1652-2354 .- 2376-2977. ; 12:4, s. 238-249
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores consumer behavioural patterns on a magazine website. By using a unique dataset of real-life click stream data from 295 magazine website visitors, interesting behavioural patterns are noted: most importantly, 86% of all sessions only visit the blogs hosted by the magazine. This means that the visitors short-circuit the start page and are not exposed to any editorial content at all, and consequently not to any commercial content on those pages. Sessions visiting editorial content, commercial content or social media links actually represent only 1% or less of all sessions recorded. Consequently, the online platform gives very limited support for the business model. Our data questions the general assumption that online platforms are key components of a contemporary magazine’s business model.
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| 9. |
- Engström, Annika, 1964-, et al.
(författare)
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Embracing the unplanned : Organizational ambidexterity within manufacturing SMEs
- 2019
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Ingår i: Academy of Management Proceedings. - : Academy of Management.
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Konferensbidrag (refereegranskat)abstract
- Organizational Ambidexterity (OA)–the ability to simultaneously pursue exploration and exploitation–is increasingly being advocated as a way to gain competitive advantage. Most of the work on OA has focused on large, multi-divisional organizations, resulting in frameworks and prescriptions that have little utility for small to medium-sized enterprises (SMEs). With this in mind, we report on the first year of an exploratory, quasi-experimental study of ambidexterity within six small-to-medium manufacturing enterprises in Sweden. The research is characterized by an emic, ‘invented here’ approach, where companies closely examine their current exploration and exploitation practices, use their findings to formulate more advanced OA approaches uniquely suited to their values and circumstances, and iteratively apply and refine these over a four year period. It appears that the construct of ‘unplanned’ and associated sub-constructs such as ‘disturbance, crashes, and interruption’ could be an important key to framing and improving OA within these SMEs and perhaps more generally.
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| 10. |
- Johansson, Anette, 1977
(författare)
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Characterising Resistance to Electrical Treeing in New XLPE-Based Materials for High-Voltage Cables
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work looks into electrical treeing in cross-linked polyethylene-based materials (XLPE), where the ability to resist tree development is considered as an indicator of improved applicability for insulation in high voltage power cables. The thesis presents results of a twin PhD project involving joint work of two students. One of the students (author of this thesis with a background in electrical engineering) concentrated on developing new methodology for testing the resistance to electrical treeing in XLPE modified by addition of voltage stabilising agents, while the design and syntheses of these agents was the domain of the second student, Markus Jarvid (having his background in chemical engineering). The latter work has been published in a separate thesis.In contrast to the traditionally used needle-electrode test objects, a wire-electrode geometry has been introduced for creating the highly divergent electric field distribution in the insulation, necessary for initiation of an electrical treeing process. The wire-electrode object has shown a benefit of producing several trees during each individual test, therefore providing more data for further analyses. These objects also allow for exposing a larger volume of the material and let trees incept in weak-spot locations. How to conveniently analyse the resulting treeing data from performed experiments is further analysed in the thesis. To increase the applicability of the elaborated methodology for testing materials characterised by different degree of transparency, optical observations of the treeing process were complimented by simultaneous detection of partial discharges (PDs). Analyses of the latter have allowed an interpretation scheme practical for measuring resistance to treeing in non-transparent materials.To evaluate how voltage stabilisers influence the resistance to treeing in XLPE, a broad range of stabilisers have been identified and tested. A detailed analysis demonstrates a positive effect imposed by addition of 4,4’-didocyloxybenzil. This compound is thereafter compared with the effect of various other stabilisers, including benzil-, thiaxanthone- fullerene- and melamine-types. Finally the stabiliser efficiencies are correlated with molecular ionisation potential and electron affinity, where it has been found that the stabilising efficiency increases with electron affinity of the added molecules. The results from this twin PhD project opens up a possibility to design new types of practically useful voltage stabilisers and test their suitability for improving the insulation in future high voltage cables.
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| 11. |
- Johansson, Jakob, 1990, et al.
(författare)
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Gas-Phase Chemistry of the NO-SO2-ClO2 System Applied to Flue Gas Cleaning
- 2018
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 57:43, s. 14347-14354
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Tidskriftsartikel (refereegranskat)abstract
- The chemical interactions that occur between NO, SO2, and ClO2 are investigated. In focus is the oxidation of NO with gaseous ClO2 for simultaneous removal of NOx and SOx from combustion-derived flue gases. Laboratory-scale experiments were conducted to examine the conversion of NO to NO2, under the following conditions: temperature range of 100-180 °C; H2O concentrations in the range of 0%-25%; ClO2-NO molar ratios in the range of 0.2-0.6; and NO and SO2 flue gas concentrations in the ranges of 0-250 ppm and 0-1000 ppm, respectively. The results show that NO is oxidized efficiently by ClO2, whereas the ClO2-SO2 reactions are insignificant. The water concentration had no effect on oxidation, and the temperature had a limited effect, within the investigated ranges. The outcomes favor the process economics of the studied application, since ClO2 consumption is negligible with respect to SO2 oxidation.
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| 12. |
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| 13. |
- Paoli, John, 1975, et al.
(författare)
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Response to the letter by Leitch et al.
- 2015
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Ingår i: Acta dermato-venereologica. - 1651-2057. ; 95:7, s. 870-1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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