| 1. |
- Kokko, K., et al.
(författare)
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Atomistic study of surfaces and interfaces of Fe-Cr and Fe-Cr-Al alloys
- 2013
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Ingår i: Physical and numerical simulation of materials processing VII. - : Trans Tech Publications Inc.. - 9783037857281 ; , s. 728-733
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Konferensbidrag (refereegranskat)abstract
- Surface and interface properties of Fe-Cr, Fe-Al, and Fe-Cr-Al are studied using Exact Muffin-Tin Orbitals and Monte Carlo methods and with x-ray photoelectron and Auger electron techniques. Surface composition is investigated as a function of oxidation (heating) time. Hard x ray photoelectron spectroscopy (HAXPES) is used to scan non destructively the compositions below the surface. It is found that Cr boosts the Al segregation to the surface.
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| 2. |
- Airiskallio, E., et al.
(författare)
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Magnetic origin of the chemical balance in alloyed Fe-Cr stainless steels : First-principles and Ising model study
- 2014
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Ingår i: Computational materials science. - : Elsevier BV. - 0927-0256 .- 1879-0801. ; 92, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- Iron-chromium is the base material for most of the stainless steel grades. Recently, new insights into the origins of fundamental physical and chemical characteristics of Fe-Cr based alloys have been achieved. Some of the new results are quite unexpected and call for further investigations. The present study focuses on the magnetic contribution in the atomic driving forces related to the chemical composition in Fe-Cr when alloyed with Al, Ti, V, Mn, Co, Ni, and Mo. Using the ab initio exact muffin-tin orbitals method combined with an Ising-type spin model, we demonstrate that the magnetic moment of the solute atoms with the induced changes in the magnetic moments of the host atoms form the main factor in determining the mixing energy and chemical potentials of low-Cr Fe-Cr based alloys. The results obtained in the present work are related to the designing and tuning of the microstructure and corrosion protection of low-Cr steels.
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| 3. |
- Airiskallio, E., et al.
(författare)
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Tuning the surface chemistry of Fe-Cr by V doping
- 2009
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 80:15
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Tidskriftsartikel (refereegranskat)abstract
- The reversal of the magnitudes of the bulk and surface chemical-potential differences induces the outburst of Cr on the otherwise pure Fe surface of Fe-Cr alloys. This threshold value for the Cr content is about 10 at. %. It is found that vanadium addition to Fe-Cr shifts the Cr threshold to a substantially lower value suggesting V having a positive effect on the corrosion resistance of low Cr steels. The obtained shift in the Cr threshold is shown to be connected to the change in volume of the alloy.
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| 4. |
- Privalova, E, et al.
(författare)
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CO2 removal with ‘switchable’ versus ‘classical’ ionic liquids
- 2012
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Ingår i: Separation and Purification Technology. - Amsterdam : Elsevier. - 1383-5866 .- 1873-3794. ; 97, s. 42-50
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Tidskriftsartikel (refereegranskat)abstract
- Switchable ionic liquids (SILs) are promising solvents for CO2 separation due to their high CO2 capturing efficiency and easy preparation compared to ‘classical’ ionic liquids. Considering viscosity, the present study has demonstrated that SILs formed at least two times stronger chemical bonds with CO2 than studied classical ionic liquids (ILs). Furthermore, the reversible properties of SILs were confirmed by evaluation of different regeneration methods. On average, molar fractions of CO2 were more than 0.3 outperforming acetate-based ILs (molar fraction of CO2 around 0.25) and more than ten times the capacity of physical ionic liquids (molar fraction 0.02). Consequently, SILs are found to be efficient CO2 absorbents operating at atmospheric pressure.HighlightsComparison of ionic liquid systems acting as chemical vs. physical solvents in practical terms. ► Recycling and reuse issues of ionic liquids in carbon dioxide capture. ► Introduction of new types of switchable ionic liquids. ► Studying the capture-release cycle behavior of the aforementioned ionic liquids. ► In essence, we have focused on engineering aspects.
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| 5. |
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| 6. |
- Airiskallio, E., et al.
(författare)
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Third element effect in the surface zone of Fe-Cr-Al alloys
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:3
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Tidskriftsartikel (refereegranskat)abstract
- The third element effect to improve the high temperature corrosion resistance of the low-Al Fe-Cr-Al alloys is suggested to involve a mechanism that boosts the recovering of the Al concentration to the required level in the Al-depleted zone beneath the oxide layer. We propose that the key factor in this mechanism is the coexistent Cr depletion that helps to maintain a sufficient Al content in the depleted zone. Several previous experiments related to our study support that conditions for such a mechanism to be functional prevail in real oxidation processes of Fe-Cr-Al alloys.
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| 7. |
- Delczeg-Czirjak, Erna, et al.
(författare)
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Effect of long-range order on elastic properties of Pd(0.5)Ag(0.5) alloy from first principles
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 84:9, s. 094205-
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Tidskriftsartikel (refereegranskat)abstract
- The effect of long-range order on single-crystal elastic constants of Pd(0.5)Ag(0.5) alloy has been investigated using first-principles electronic structure calculations. The lowest energy among the considered ordered, partially ordered, and disordered structures is found to be the L1(1) layered structure, which is formed by alternate (111) Pd and Ag layers. The ordering effect is found to follow a clear trend: in contrast to the disordered phase, for which the K(a) and K(c) compressibilities are equal, the L1(1) structure becomes less compressible along the c axis than along the a axis.
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| 8. |
- Lagerspetz, E., et al.
(författare)
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Pervasive Communities in the Internet of People
- 2018
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Ingår i: 2018 IEEE International Conference on Pervasive Computing and Communications Workshops, PerCom Workshops 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538632277 ; , s. 40-45
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Konferensbidrag (refereegranskat)abstract
- The Internet has traditionally been a device-oriented architecture where devices with IP addresses are first-class citizens, able to serve and consume content or services, and their owners take part in the interaction only through those devices. The Internet of People (IoP) is a recent paradigm where devices become proxies of their users, and can act on their behalf. To realize IoP, new policies and rules for how devices can take actions are required. The role of context information grows as devices act autonomously based on the environment and existing social relationships between their owners. In addition, the social profiles of device owners determine e.g. how altruistic or resourceconserving they are in collaborative computing scenarios. In this paper we focus on community formation in IoP, a prerequisite for enabling collaborative scenarios, and discuss main challenges and propose potential solutions. © 2018 IEEE.
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| 9. |
- Heinonen, M. H., et al.
(författare)
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Initial Oxidation of Fe-Al and Fe-Cr-Al Alloys : Cr as an Alumina Booster
- 2011
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Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 0030-770X .- 1573-4889. ; 76:3-4, s. 331-346
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Tidskriftsartikel (refereegranskat)abstract
- The boosting effect of Cr on the growth of the protective alumina scale on Fe-Al alloys is investigated by X-ray photoelectron spectroscopy. Using low oxygen pressure the surface chemistry of the alloys is monitored starting from the first moments of oxidation. Chromium affects the Fe/Al surface-bulk exchange which is clearly detected by analyzing the measured surface concentrations within the atomic concentration models. Experimental results presented are in good agreement with the previous ones obtained by experiments at ambient conditions and ab initio calculations.
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| 10. |
- Plötner, Björn, et al.
(författare)
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Chlorosis caused by two recessively interacting genes reveals a role of RNA helicase in hybrid breakdown in Arabidopsis thaliana
- 2017
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Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 91:2, s. 251-262
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Tidskriftsartikel (refereegranskat)abstract
- Hybrids often differ in fitness from their parents. They may be superior, translating into hybrid vigour or heterosis, but they may also be markedly inferior, because of hybrid weakness or incompatibility. The underlying genetic causes for the latter can often be traced back to genes that evolve rapidly because of sexual or host-pathogen conflicts. Hybrid weakness may manifest itself only in later generations, in a phenomenon called hybrid breakdown. We have characterized a case of hybrid breakdown among two Arabidopsis thaliana accessions, Shahdara (Sha, Tajikistan) and Lövvik-5 (Lov-5, Northern Sweden). In addition to chlorosis, a fraction of the F2 plants have defects in leaf and embryo development, and reduced photosynthetic efficiency. Hybrid chlorosis is due to two major-effect loci, of which one, originating from Lov-5, appears to encode an RNA helicase (AtRH18). To examine the role of the chlorosis allele in the Lövvik area, in addition to eight accessions collected in 2009, we collected another 240 accessions from 15 collections sites, including Lövvik, from Northern Sweden in 2015. Genotyping revealed that Lövvik collection site is separated from the rest. Crosses between 109 accessions from this area and Sha revealed 85 cases of hybrid chlorosis, indicating that the chlorosis-causing allele is common in this area. These results suggest that hybrid breakdown alleles not only occur at rapidly evolving loci, but also at genes that code for conserved processes.
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