| 1. |
- Over, H, et al.
(författare)
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Visualization of atomic processes on ruthenium dioxide using scanning tunneling microscopy
- 2004
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Ingår i: ChemPhysChem. - : Wiley. - 1439-7641 .- 1439-4235. ; 5:2, s. 167-174
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Forskningsöversikt (refereegranskat)abstract
- The visualization of surface reactions on the atomic scale provides direct insight into the microscopic reaction steps taking place in a catalytic reaction at a (model) catalyst's surface. Employing the technique of scanning tunneling microscopy (STM), we investigated the CO oxidation reaction over the RuO2(110) and RuO2(100) surfaces. For both surfaces the protruding bridging O atoms are imaged in STM as bright features. The reaction mechanism is identical on both orientations of RuO2. CO molecules adsorb on the undercoordinated surface Ru atoms from where they recombine with undercoordinated O atoms to form CO2 at the oxide surface. In contrast to the RuO2(110) surface, the RuO2(100) surface stabilizes also a catalytically inactive c(2 x 2) phase may play an important role in the deactivation of RuO2 catalysts in the electrochemical Cl-2 evolution and other heterogeneous reactions.
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| 2. |
- Mupeta, Henry, et al.
(författare)
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Techno-economic analysis of PV-Diesel hybrid system as an option for rural electrification in Zambia
- 2021
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Ingår i: 13<sup>th</sup> Internationational conference on Sustainable Energy and Environmental Protection: Solar Energy, Vienna, Austria, September 13-16, 2021. - 9783900932879
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Konferensbidrag (refereegranskat)abstract
- The study explores the viability of the PV-Diesel Hybrid system for rural electrification in Sub-Sahara Africa with a study case of a remote district without access to electricity in the Northern Province of Zambia. Using HOMER (Hybrid Optimization of Multiple Electric Renewables) software, the study investigates the best and most feasible technical solution through different hybrid system configurations and combinations, taking into account the least Levelized Cost of Electricity of the project. The results show that operating diesel generators as stand-alone is not economically sustainable and gives a high LCoE due to variability in diesel pump prices, and a high cost of operation and maintenance. Furthermore, the study shows that the initial capital cost of solar energy projects in Zambia is relatively high compared to the equivalent diesel-based plants. However, the authors project that this will likely change because of the continued downward trend in capital costs of PV per kWp. Additionally, the high initial capital costs are offset by the low operational costs and the clean/environmentally friendly energy from PV systems.
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| 3. |
- Engwall, Olov, et al.
(författare)
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Identification of Low-engaged Learners in Robot-led Second Language Conversations with Adults
- 2022
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Ingår i: ACM Transactions on Human-Robot Interaction. - : Association for Computing Machinery (ACM). - 2573-9522. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- The main aim of this study is to investigate if verbal, vocal, and facial information can be used to identify low-engaged second language learners in robot-led conversation practice. The experiments were performed on voice recordings and video data from 50 conversations, in which a robotic head talks with pairs of adult language learners using four different interaction strategies with varying robot-learner focus and initiative. It was found that these robot interaction strategies influenced learner activity and engagement. The verbal analysis indicated that learners with low activity rated the robot significantly lower on two out of four scales related to social competence. The acoustic vocal and video-based facial analysis, based on manual annotations or machine learning classification, both showed that learners with low engagement rated the robot's social competencies consistently, and in several cases significantly, lower, and in addition rated the learning effectiveness lower. The agreement between manual and automatic identification of low-engaged learners based on voice recordings or face videos was further found to be adequate for future use. These experiments constitute a first step towards enabling adaption to learners' activity and engagement through within- and between-strategy changes of the robot's interaction with learners.
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| 4. |
- Joffard, Nina, et al.
(författare)
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Digest : The role of postzygotic isolation in Mimulus speciation
- 2021
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Ingår i: Evolution: international journal of organic evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 75:3, s. 756-758
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Tidskriftsartikel (refereegranskat)abstract
- Recently diverged species often show incomplete reproductive isolation and subsequently experience hybridization and introgression. The plant genus Mimulus includes many such examples of closely related taxa that prove useful for studying incipient speciation. However, Sandstedt et al. show that in contrast to other Mimulus species, species of the M. tilingii complex are characterized by strong postzygotic isolation mediated by multiple barriers. This finding highlights the diverse speciation histories of related plant groups.
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| 5. |
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| 6. |
- Over, H., et al.
(författare)
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In situ structure-activity correlation experiments of the ruthenium catalyzed CO oxidation reaction
- 2009
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861. ; 145:3-4, s. 236-242
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Konferensbidrag (refereegranskat)abstract
- The complex structure-activity correlation of the CO oxidation on ruthenium has been studied in a batch reactor by using in situ surface X-ray diffraction (SXRD) and on-line mass spectrometry. Two distinct active phases are identified at higher pressures in the mbar range depending on the reaction conditions: a non-oxidic phase and a RuO2(1 1 0) layer of variable thickness ranging from 1.5 nm to 10 nm. For reaction temperatures lower than 520 K the experimental turnover frequency (TOF) numbers are shown to be almost identical for the two types of active phases. Above 520 K the RuO2(1 1 0) layer turned out to be much more active than the non-oxidic phase. Kinetic reaction experiments on the RuO2(1 1 0) phase reveal an activation energy of 78 +/- 10 kJ/mol which is in perfect agreement with corresponding reactivity experiments on supported and powder RuO2 catalyst. Under oxidizing reaction conditions and high concentration of CO2 in the gas mixture, the RuO2(1 1 0) model catalyst shows reversible product-poisoning. (C) 2008 Elsevier B.V. All rights reserved.
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| 9. |
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| 10. |
- Falasca, Kajsa, 1976-
(författare)
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Not minimal but more difficult to measure : A panel study of media effects
- 2018
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Ingår i: Observatorio (OBS*). - 1646-5954. ; 12:3, s. 48-65
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Tidskriftsartikel (refereegranskat)abstract
- Traditional media effect theories as agenda-setting theory have recently been questioned due to the development of the media environment with media fragmentation and individualized media consumption. Other scholars disagree and suggest that a distinction has to be made between actual media effects and the ease with which they can be measured. Given this scholarly discussion the purpose of this study is to investigate and compare the agenda-setting effects of different media consumption measures on individual issue salience. The study is based on a panel survey that includes different measures of consumption: (1) general news media attention, (2) exposure to different media types such as traditional news media, online news media, and political social media. Overall, the findings suggest that general news media attention might be a more significant measure for consumption in a high-choice media environment. In essence, this study suggests that agenda-setting effects are not becoming non-significant but rather difficult to measure.
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