| 1. |
- Ahlbäck Öberg, Shirin, et al.
(author)
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Projektsamhället och hoten mot akademin
- 2016
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In: Det hotade universitetet. - Stockholm : Dialogos Förlag. - 9789175042992 ; , s. 9-26
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Book chapter (other academic/artistic)
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| 2. |
- Bennich-Björkman, Li, 1960-, et al.
(author)
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Dags för Lemne att lämna
- 2015
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In: Upsala Nya Tidning. ; march 13
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Journal article (pop. science, debate, etc.)
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| 3. |
- Björnsson, Lars Henrik, 1984, et al.
(author)
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Electrification of the two-car household: PHEV or BEV?
- 2017
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In: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 85, s. 363-376
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Journal article (peer-reviewed)abstract
- In previous works, we have shown two-car households to be better suited than one-car households for leveraging the potential benefits of the battery electric vehicle (BEV), both when the BEV simply replaces the second car and when it is used optimally in combination with a conventional car to overcome the BEV’s range limitation and increase its utilization. Based on a set of GPS-measured car movement data from 64 two-car households in Sweden, we here assess the potential electric driving of a plug-in hybrid electric vehicle (PHEV) in a two-car household and compare the resulting economic viability and potential fuel substitution to that of a BEV. Using estimates of near-term mass production costs, our results suggest that, for Swedish twocar households, the PHEV in general should have a higher total cost of ownership than the BEV, provided the use of the BEV is optimized. However, the PHEV will increasingly be favored if, for example, drivers cannot or do not want to optimize usage. In addition, the PHEV and the BEV are not perfect substitutes. The PHEV may be favored if drivers require that the vehicle be able to satisfy all driving needs (i.e., if drivers don’t accept the range and charge-time restrictions of the BEV) or if drivers requires an even larger battery in the BEV to counter range anxiety. We find that, given a particular usage strategy, the electric drive fraction (EDF) of the vehicle fleet is less dependent on whether PHEVs or BEVs are used to replace one of the conventional cars in two-car households. Instead, the EDF depends more on the usage strategy, i.e., on whether the PHEV/BEV is used to replace the conventional car with the higher annual mileage (“the first car”), the less used car (“the second car”), or is used flexibly to substitute for either in order to optimize use. For example, from a fuel replacement perspective it is often better to replace the first car with a PHEV than to replace the second with a BEV.
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| 4. |
- Björnsson, Lars Henrik, 1984, et al.
(author)
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Objective functions for plug-in hybrid electric vehicle battery range optimization and possible effects on the vehicle fleet
- 2018
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In: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 86, s. 655-669
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Journal article (peer-reviewed)abstract
- While a hybrid electric vehicle (HEV) mainly runs on the same fuel as a conventional combustion engine, a plug-in hybrid electric vehicle (PHEV) has the potential to replace most of that fuel with electricity from the grid. Further, the driving-range limitations associated with a pure battery electric vehicle (BEV) do not apply to the PHEV. This makes the PHEV an interesting option for reducing greenhouse gas (GHG) emissions and local air pollutants as well as energy dependence, without sacrificing performance. However, how large fuel reduction that could be expected from PHEVs strongly depends on the battery range and driving and charging patterns (Björnsson and Karlsson, 2015). To maximize fuel reduction, battery capacity should be designed to reach a high share of electric driving. However, maximizing fuel reduction might not be the main objective for all stakeholders when optimizing battery range. Car owners could be more interested in reaching a low total cost of ownership (TCO), while manufacturers might focus on a battery range that suits as many potential buyers as possible. In this study, we analyze how the optimal battery range for the PHEV and the resulting vehicle fleet properties vary with the choice of objective function under various techno-economic conditions and policy options.
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| 5. |
- Björnsson, Lars Henrik, 1984, et al.
(author)
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Plug-in hybrid electric vehicles: How individual movement patterns affect battery requirements, the potential to replace conventional fuels, and economic viability
- 2015
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In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 143, s. 336-347
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Journal article (peer-reviewed)abstract
- Using GPS data logged for a representative sample of individual vehicles in private use, we assess the viability of plug-in hybrid electric vehicles (PHEVs) in Sweden for a wide range of techno-economic conditions. We determine requirements for PHEVs with the aid of a simple parameterization used to analyze the GPS data covering number of trips, driving distance per trip, and parking times, logged for 30 days or longer, for 432 conventional Swedish cars. Good opportunities for charging and regular distances traveled between rechargings increase the potential for battery-powered driving and, along with a high annual mileage, enhance the viability of the PHEV. Therefore, commuters are likely to be the first drivers for whom the PHEV will be cost-effective. Making charging infrastructure available at work places would enhance the opportunity for this group of early adopters, as we show that charging while at work is comparable at the-initial stage to halving the marginal battery costs for the average commuter.
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| 6. |
- Björnsson, Lars Henrik, 1984, et al.
(author)
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The potential for brake energy regeneration under Swedish conditions
- 2016
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In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 168, s. 75-84
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Journal article (peer-reviewed)abstract
- The ability to regenerate energy when braking is a valuable advantage of hybrid and fully electric vehicles. The regeneration potential mainly depends on how a car is driven and on the capacity of the drivetrain. Detailed studies of the regeneration potential based on brake energy in real-world driving are needed to better understand the potential gains of car-electrification, since test cycles do not take individual driving characteristics or route elevation into account. This study uses a model of a normalized vehicle and a highly detailed and representative data set of individual car movements including elevation to analyze the potential for energy regeneration in cars when driven under current real-world Swedish conditions.The ultimate energy regeneration potential (defined as the braking energy at the wheels) varies by about a factor of six among individual movement patterns, with an average of 0.033 kW h/km, corresponding to 27% of the total average energy supplied at the wheels. Earlier studies have shown a higher energy regeneration potential per km for cars driving under urban conditions with low average velocity and many starts and stops. Our results confirm this but also point out that a low average velocity and a high share of city driving are not very well correlated with the yearly energy savings; for this the yearly mileage is a more important indicator. This suggests that drivers who rack up the miles should be targeted as potential early adopters of regenerative technologies rather than city drivers per se. The results from real-world driving are compared to the NEDC and WLTP test cycles.
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| 7. |
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| 8. |
- Böiers, Charlotta, et al.
(author)
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A Human IPS Model Implicates Embryonic B-Myeloid Fate Restriction as Developmental Susceptibility to B Acute Lymphoblastic Leukemia-Associated ETV6-RUNX1
- 2018
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In: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 44:3, s. 7-377
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Journal article (peer-reviewed)abstract
- ETV6-RUNX1 is associated with childhood acute B-lymphoblastic leukemia (cALL) functioning as a first-hit mutation that initiates a clinically silent pre-leukemia in utero. Because lineage commitment hierarchies differ between embryo and adult, and the impact of oncogenes is cell-context dependent, we hypothesized that the childhood affiliation of ETV6-RUNX1 cALL reflects its origins in a progenitor unique to embryonic life. We characterize the first emerging B cells in first-trimester human embryos, identifying a developmentally restricted CD19−IL-7R+ progenitor compartment, which transitions from a myeloid to lymphoid program during ontogeny. This developmental series is recapitulated in differentiating human pluripotent stem cells (hPSCs), thereby providing a model for the initiation of cALL. Genome-engineered hPSCs expressing ETV6-RUNX1 from the endogenous ETV6 locus show expansion of the CD19−IL-7R+ compartment, show a partial block in B lineage commitment, and produce proB cells with aberrant myeloid gene expression signatures and potential: features (collectively) consistent with a pre-leukemic state. Böiers, Richardson et al. explore the potential for a developmental susceptibility to childhood acute lymphoblastic leukemia. Characterization of earliest B cell progenitors in human fetal liver identified a unique progenitor compartment that can be recapitulated using human pluripotent stem cells to model the impact of the pre-leukemia-initiating oncogene ETV6-RUNX1.
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| 9. |
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Det hotade universitetet
- 2016. - 1
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Editorial collection (peer-reviewed)abstract
- Under de drygt två hundra år som förflutit sedan det moderna forskningsuniversitetet såg dagens ljus i dåtida Preussen har vetenskap bevisligen gjort världen bättre. Fyra k:n – kunskap, kreativitet, kritikoch kollegialitet – har utgjort nyckeln till denna exempellösa framgång. Akademins framsteg har dock inte vilat på den demokratisk-politiska logik som genomsyrar dagens samhälle, utan på en parallell och alldeles egen verklighet där ett fritt sökande upprätthållits genom att forskare drivits av sitt engagemang och sin nyfikenhet. När denna anda får råda inom vetenskapen blir det också bra för samhället i stort. Men i det projektsamhälle som alltmer tar form och där tiden, resultaten och utvärderingen är centrala, framstår akademins och vetenskapens sätt att fungera som provocerande. Liksom stora delar av den offentliga verksamheten lever i dag akademin under trycket av kortsiktig resultatleverans.Hur kunde det bli så, och vad gör vi åt det?Denna problematik är temat för Det hotade universitetet, som är redigerad och författad av engagerade forskare, tidigare universitetsrektorer och ämbetsmän som är förskräckta över en utveckling där djup kunskap, vildsint kreativitet, kritiska samtal och kollegialt ansvar kastas på sophögen. Denna utveckling kan inte, och får inte, fortsätta. Då rycker vi undan mattan för mänskliga framsteg och ett civiliserat samhälle. Det är hög tid att försvara de värden som akademin har stått för sedan lång tid tillbaka – inte för att de är traditionella, utan för att de är det modernaste vi har.
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| 10. |
- Granquist, Linda, et al.
(author)
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Optimization of peak area precision of a GC-MS drug screening method using a nonparametric sign test
- 2019
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In: Accreditation and Quality Assurance. - : SPRINGER. - 0949-1775 .- 1432-0517. ; 24:3, s. 215-226
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Journal article (peer-reviewed)abstract
- The optimization of a number ofgas chromatography-mass spectrometry (GC-MS) parameters in order to improve peak area precision through the application of a nonparametric statistical test (the sign test) is demonstrated. As an example, the drug screening method used at the Swedish National Forensic Centre (NFC) is optimized, but in principle, any GC-MS method could be optimized using this approach. The GC-MS parameters investigated were those often overlooked in the optimization process, namely injection volume, liner type, oven temperature program, final oven temperature, MS scan range and MS scan rate. The influence of these parameters on the precision of the peak area responses of 11 different compounds in a test mixture was evaluated using the sign test for pairwise comparison. This nonparametric test provides probability values which facilitate the ranking of parameters according to their influence on peak area variation as well as providing a measure of their statistical significance. This study presents the resulting optimized method and shows that the decreased total variation depended predominantly on liner type and MS scan rate settings. This work also shows that optimization of analytical methods can be achieved using simple and easily accessible statistical tools.
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| 11. |
- Haghighi, Mona, et al.
(author)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Hosseini, Vahid A., 1987-, et al.
(author)
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Nitrogen loss and effects on microstructure in multipass TIG welding of a super duplex stainless steel
- 2016
-
In: Materials & design. - : Elsevier Ltd. - 0264-1275 .- 1873-4197. ; 98, s. 88-97
-
Journal article (peer-reviewed)abstract
- Nitrogen loss is an important phenomenon in welding of super duplex stainless steels. In this study, a super duplex stainless steel was autogenously TIG-welded with one to four bead-on-plate passes with low or high heat inputs using pure argon shielding gas. The goal was to monitor nitrogen content and microstructure for each weld pass. Nitrogen content, measured by wavelength dispersive X-ray spectrometry, was after four passes reduced from 0.28 wt% in the base metal to 0.17 wt% and 0.10 wt% in low and high heat input samples, respectively. Nitrogen loss resulted in a more ferritic structure with larger grains and nitride precipitates. The ferrite grain width markedly increased with increasing number of passes and heat input. Ferrite content increased from 55% in base metal to 75% at low and 79% at high heat inputs after four passes. An increasing amount of nitrides were seen with increasing number of weld passes. An equation was suggested for calculation of the final nitrogen content of the weld metal as functions of initial nitrogen content and arc energy. Acceptable ferrite contents were seen for one or two passes. The recommendation is to use nitrogen in shielding gas and proper filler metals.
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| 18. |
- Hosseini, Vahid, 1987-, et al.
(author)
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Correction to : Time-temperature-precipitation and property diagrams for super duplex stainless steel weld metals (Welding in the World, (2018), 62, 3, (517-533), 10.1007/s40194-018-0548-z)
- 2018
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In: Welding in the World. - : Springer Science and Business Media LLC. - 0043-2288 .- 1878-6669. ; 62:4, s. 893-
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Journal article (peer-reviewed)abstract
- Unfortunately due to typesetting mistakes, Tables 4-€“6 have been displayed erroneously in the article. © 2018, International Institute of Welding.
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| 19. |
- Hosseini, Vahid, 1987-, et al.
(author)
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Effect of sigma phase morphology on the degradation of properties in a super duplex stainless steel
- 2018
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In: Materials. - : MDPI AG. - 1996-1944. ; 11:6
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Journal article (peer-reviewed)abstract
- Sigma phase is commonly considered to be the most deleterious secondary phase precipitating in duplex stainless steels, as it results in an extreme reduction of corrosion resistance and toughness. Previous studies have mainly focused on the kinetics of sigma phase precipitation and influences on properties and only a few works have studied the morphology of sigma phase and its influences on material properties. Therefore, the influence of sigma phase morphology on the degradation of corrosion resistance and mechanical properties of 2507 super duplex stainless steel (SDSS) was studied after 10 h of arc heat treatment using optical and scanning electron microscopy, electron backscattered diffraction analysis, corrosion testing, and thermodynamic calculations. A stationary arc was applied on the 2507 SDSS disc mounted on a water-cooled chamber, producing a steady-state temperature gradient covering the entire temperature range from room temperature to the melting point. Sigma phase was the major intermetallic precipitating between 630 °C and 1010 °C and its morphology changed from blocky to fine coral-shaped with decreasing aging temperature. At the same time, the average thickness of the precipitates decreased from 2.9 μm to 0.5 μm. The chemical composition of sigma was similar to that predicted by thermodynamic calculations when formed at 800-900 °C, but deviated at higher and lower temperatures. The formation of blocky sigma phase introduced local strain in the bulk of the primary austenite grains. However, the local strain was most pronounced in the secondary austenite grains next to the coral-shaped sigma phase precipitating at lower temperatures. Microstructures with blocky and coral-shaped sigma phase particles were prone to develop microscale cracks and local corrosion, respectively. Local corrosion occurred primarily in ferrite and in secondary austenite, which was predicted by thermodynamic calculations to have a low pitting resistance equivalent. To conclude, the influence of sigma phase morphology on the degradation of properties was summarized in two diagrams as functions of the level of static load and the severity of the corrosive environment.
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| 20. |
- Hosseini, Vahid, 1987-, et al.
(author)
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Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method
- 2018
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In: Materials Characterization. - : Elsevier BV. - 1044-5803 .- 1873-4189. ; 139, s. 390-400
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Journal article (peer-reviewed)abstract
- A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to a steady state temperature gradient for 10 h. A new experimental approach was used to map precipitation in microstructure, covering aging temperatures of up to 1430 °C. The microstructure was characterized and functionality was evaluated via hardness mapping. Nitrogen depletion adjacent to the fusion boundary depressed the upper temperature limit for austenite formation and influenced the phase balance above 980 °C. Austenite/ferrite boundaries deviating from Kurdjumov–Sachs orientation relationship (OR) were preferred locations for precipitation of σ at 630–1000 °C, χ at 560–1000 °C, Cr2N at 600–900 °C and R between 550 °C and 700 °C. Precipitate morphology changed with decreasing temperature; from blocky to coral-shaped for σ, from discrete blocky to elongated particles for χ, and from polygonal to disc-shaped for R. Thermodynamic calculations of phase equilibria largely agreed with observations above 750 °C when considering nitrogen loss. Formation of intermetallic phases and 475 °C-embrittlement resulted in increased hardness. A schematic diagram, correlating information about phase contents, morphologies and hardness, as a function of exposure temperature, is introduced for evaluation of functionality of microstructures.
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| 21. |
- Hosseini, Vahid, 1987-, et al.
(author)
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Predicting ferrite fractions in single pass super duplex stainless steel welds : thermal cycle analysis and phase transformation modeling
- 2019
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In: ESSC and DUPLEX 2019. - Wien : Austrian Society for Metallurgy and Materials (ASMET). ; , s. 180-197
-
Conference paper (peer-reviewed)abstract
- The relationship between welding process parameters, welding thermal cycle, and the final microstructure is of great importance for reliable fabrication of welded super duplex stainless steels (SDSS) structures. The present study was primarily aimed at investigating the relationship for root/single pass welding of type 2507 SDSS. Fourteen welds were produced using GMAW, GTAW, SAW, and SMAW with different joints geometries, plate thicknesses, and welding parameters. Thermal cycles were recorded using several thermocouples attached to the plates and thermocouples were also harpooned into the weld pool. Weld pool geometries and base metal dilution in the weld metal were determined for all welds. The general trend was that the ferrite fraction of the weld zone increased with increasing cooling rate and base metal dilution in the weld metal. The ferrite fraction was in the range 49-64% for all welds. Kinetics of austenite formation was modeled using computational thermodynamics (Thermo-Calc & DICTRA) to predict the ferrite fractions in the weld zone and calculated fractions were in good agreement with experimental results. Some conflicting results showed that in addition to dilution and cooling rate, the possible nitrogen loss must be taken into account when evaluating and predicting ferrite fraction. It was concluded that the above approach can be used for prediction of the ferrite fraction of super duplex stainless steel single pass welds. Â 2019 ESSC and DUPLEX 2019 - 10th European Stainless Steel Conference - Science and Market, 6th European Duplex Stainless Steel Conference and Exhibition. All rights reserved.
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| 22. |
- Hosseini, Vahid, 1987-, et al.
(author)
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Spinodal Decomposition in Functionally Graded Super Duplex Stainless Steel and Weld Metal
- 2018
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In: Metallurgical and Materials Transactions. A. - : Springer Science and Business Media LLC. - 1073-5623 .- 1543-1940. ; 49A:7, s. 2803-2816
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Journal article (peer-reviewed)abstract
- Low-temperature phase separations (T < 500 °C), resulting in changes in mechanical and corrosion properties, of super duplex stainless steel (SDSS) base and weld metals were investigated for short heat treatment times (0.5 to 600 minutes). A novel heat treatment technique, where a stationary arc produces a steady state temperature gradient for selected times, was employed to fabricate functionally graded materials. Three different initial material conditions including 2507 SDSS, remelted 2507 SDSS, and 2509 SDSS weld metal were investigated. Selective etching of ferrite significantly decreased in regions heat treated at 435 °C to 480 °C already after 3 minutes due to rapid phase separations. Atom probe tomography results revealed spinodal decomposition of ferrite and precipitation of Cu particles. Microhardness mapping showed that as-welded microstructure and/or higher Ni content accelerated decomposition. The arc heat treatment technique combined with microhardness mapping and electrolytical etching was found to be a successful approach to evaluate kinetics of low-temperature phase separations in SDSS, particularly at its earlier stages. A time-temperature transformation diagram was proposed showing the kinetics of 475 °C-embrittlement in 2507 SDSS.
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| 23. |
- Hosseini, Vahid, 1987-, et al.
(author)
-
Time-temperature-precipitation and property diagrams for super duplex stainless steel weld metals
- 2018
-
In: Welding in the World. - : Springer Science and Business Media LLC. - 0043-2288 .- 1878-6669. ; 62:3, s. 517-533
-
Journal article (peer-reviewed)abstract
- Super duplex stainless steel (SDSS) weld metal microstructures, covering the complete temperature range from ambient to liquidus, were produced by arc heat treatment for 1 and 10 min. Temperature modeling and thermodynamic calculations complemented microstructural studies, hardness mapping and sensitization testing. After 1 min, intermetallics such as sigma and chi phase had precipitated, resulting in moderate sensitization at 720–840 °C. After 10 min, larger amounts of intermetallics resulted in hardness up to 400 HV0.5 and more severe sensitization at 580–920 °C. Coarse and fine secondary austenite precipitated at high and low temperatures, respectively: The finer secondary austenite was more detrimental to corrosion resistance due to its lower content of Cr, Mo, and N as predicted by thermodynamic calculations. Increased hardness and etching response suggest that 475 °C embrittlement had occurred after 10 min. Results are summarized as time-temperature-precipitation and property diagrams for hardness and sensitization.
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| 24. |
- Jakobsson, Niklas, 1985, et al.
(author)
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Are multi-car households better suited for battery electric vehicles? - Driving patterns and economics in Sweden and Germany
- 2016
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In: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 65, s. 1-15
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Journal article (peer-reviewed)abstract
- Battery electric vehicles (BEVs) could reduce CO2 emissions from the transport sector but their limited electric driving range diminishes their utility to users. The effect of the limited driving range can be reduced in multi-car households where users could choose between a BEV and a conventional car for long-distance travel. However, to what extent the driving patterns of different cars in a multi-car household’s suit the characteristics of a BEV needs further analysis. In this paper we analyse the probability of daily driving above a fixed threshold for conventional cars in current Swedish and German car driving data. We find second cars in multi-car households to require less adaptation and to be better suited for BEV adoption compared to first cars in multi-car households as well as to cars in single-car households. Specifically, the share of second cars that could fulfil all their driving is 20 percentage points higher compared to first cars and cars from single-car households. This result is stable against variation of driving range and of the tolerated number of days requiring adaptation. Furthermore, the range needed to cover all driving needs for about 70% of the vehicles is only 220 km for second cars compared to 390 km for the average car. We can further confirm that second cars have higher market viability from a total cost of ownership perspective. Here, the second cars achieve a 10 percentage points higher market share compared to first cars, and to cars in single-car households for Swedish economic conditions, while for Germany the corresponding figure is 2 percentage points. Our results are important for understanding the market viability of current and near-future BEVs.
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| 25. |
- Jakobsson, Niklas, 1985, et al.
(author)
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How are driving patterns adjusted to the use of a battery electric vehicle in two-car households?
- 2016
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In: Electric Vehicle Symposium 29, Montreal, 2016-06-20. - 9781510832701 ; 2, s. 1021-1030
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Conference paper (peer-reviewed)abstract
- We have supplied two-car households with a Volkswagen e-Golf to replace one of their conventional cars for 3-4 months and measured their driving with GPS equipment. The measurements contain data of the driving of both household cars, before, and after they obtained an EV. Our analysis focus on the uptake of driving for the EV, as well as the driving adaptation the households made when acquiring the EV. Results show a small uptake of driving for the EV and a large heterogeneity in adaptation, where some household increase the EV driving compared to the removed car, and some decrease it.
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