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Leduc, J., Goenuellue, Y., Ghamgosar, P., You, S., Mouzon, J., Choi, H., . . . Mathur, S. (2019). Electronically-Coupled Phase Boundaries in α‑Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation. ACS APPLIED NANO MATERIALS, 2(1), 334-342
Open this publication in new window or tab >>Electronically-Coupled Phase Boundaries in α‑Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation
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2019 (English)In: ACS APPLIED NANO MATERIALS, E-ISSN 2574-0970, Vol. 2, no 1, p. 334-342Article in journal (Refereed) Published
Abstract [en]

Photoelectrochemical (PEC) water splittingreactions are promising for sustainable hydrogen productionfrom renewable sources. We report here, the preparation of α-Fe2O3/Fe3O4 composite films via a single-step chemical vapordeposition of [Fe(OtBu)3]2 and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidationactivity (0.48 mA/cm2 at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm2) standard illumination was found forhybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from ahigher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe2O3) and ferrimagnetic (Fe3O4) oxides, which in view of their differential chemical constitution andvalence states of Fe ions (Fe2+/Fe3+) can enhance the charge separation and thus the overall electrical conductivity of the layer.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
solar water splitting, valence dynamics, magnetite, Raman, single-source CVD, heterostructures
National Category
Composite Science and Engineering Chemical Process Engineering
Research subject
Experimental Physics; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-73139 (URN)10.1021/acsanm.8b01936 (DOI)000464491500036 ()
Note

Validerad;2019;Nivå 2;2019-03-13 (oliekm)

Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-08-23Bibliographically approved
Nabavi, M. S., Zhou, M., Mouzon, J., Grahn, M. & Hedlund, J. (2019). Stability of colloidal ZSM-5 catalysts synthesized in fluoride and hydroxide media. Microporous and Mesoporous Materials, 278, 167-174
Open this publication in new window or tab >>Stability of colloidal ZSM-5 catalysts synthesized in fluoride and hydroxide media
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2019 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 167-174Article in journal (Refereed) Published
Abstract [en]

ZSM-5 zeolite crystals with carefully controlled thicknesses in the range 20–110 nm, i.e. in the colloidal domain, were synthesized in fluoride and hydroxide media. The crystals were treated in steam at high temperature to evaluate the stability and evaluated by SEM, XRD, NMR and NH3-TPD. The results showed that the framework of crystals synthesized in fluoride media was more stable than the framework of crystals synthesized in hydroxide media. This should be an effect of lower concentration of structural defects and silanol groups in the former zeolites as reported by other groups. However, independently of the synthesis conditions, all crystals dealuminated rapidly when treated with steam at the conditions investigated in the present work.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
ZSM-5, Catalyst, Stability, Framework, Steam, Dealumination
National Category
Chemical Process Engineering
Research subject
Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-71897 (URN)10.1016/j.micromeso.2018.11.007 (DOI)000459841900020 ()2-s2.0-85057248871 (Scopus ID)
Note

Validerad;2019;Nivå 2;2018-12-05 (svasva)

Available from: 2018-12-05 Created: 2018-12-05 Last updated: 2019-04-12Bibliographically approved
Sefidari, H., Lindholm, B., Wiinikka, H., Nordin, L. O., Mouzon, J., Bhuiyan, I. U. & Öhman, M. (2018). The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part I: Characterization of process gas particles and deposits. Fuel processing technology, 177, 283-298
Open this publication in new window or tab >>The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part I: Characterization of process gas particles and deposits
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2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 177, p. 283-298Article in journal (Refereed) Published
Abstract [en]

o initiate the elucidation of deposit formation during the iron-ore pelletization process, a comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal-fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale grate-kiln setup. Particles and deposits were sampled from 3 positions of different temperature via a water-cooled sampling probe. Three distinct fragmentation modes were identified based on the aerodynamic particle diameter (Dp). The fine mode: Particles with 0.03 < Dp < 0.06 μm. The first fragmentation mode: Particles with 1 < Dp < 10 μm. The second fragmentation mode: Coarse particles (cyclone particles, Dp > 10 μm). A transition from a bimodal PSD (particle size distribution) to a trimodal PSD was observed when pellet dust was added (Case 3) and consequently the elemental bulk composition of the abovementioned modes was changed. The most extensive interaction between pellet dust and coal-ash particles was observed in the coarse mode where a significant number of coal ash globules were found attached to the surface of the hematite particles. The morphology of the sharp-edged hematite particles was changed to smooth-edged round particles which proved that hematite particles must have interacted with the surrounding aluminosilicate glassy phase originating from the coal ash. The short-term deposits collected during coal combustion (Case 1) were highly porous in contrast to the high degree of sintering observed in the experiments with pellet dust addition (Case 3) which is attributed to the dissolution of hematite particles in the aluminosilicate glassy phase. The results suggest that pellet dust itself (Case 2) has low slagging tendency, independent of temperature. However, when coal-ash is present (Case 3), auxiliary phases are added such that tenacious particles are formed and slagging occurs.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering Chemical Engineering Chemical Process Engineering
Research subject
Energy Engineering; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-68712 (URN)10.1016/j.fuproc.2018.05.004 (DOI)000437819600030 ()2-s2.0-85046802389 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-05-14 (andbra)

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2019-01-18Bibliographically approved
Sefidari, H., Lindblom, B., Wiinikka, H., Nordin, L. O., Lennartsson, A., Mouzon, J., . . . Öhman, M. (2018). The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part II: Thermochemical equilibrium calculations and viscosity estimations. Fuel processing technology, 180, 189-206
Open this publication in new window or tab >>The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part II: Thermochemical equilibrium calculations and viscosity estimations
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2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 180, p. 189-206Article in journal (Refereed) Published
Abstract [en]

Fly ash particles from the combustion of solid-fuels together with disintegrated particles arising from iron-ore pellets result in accumulation of deposits on the refractory linings of the grate-kiln induration machine during the iron-ore pelletizing process. The deposits amass in the high-temperature regions of the induration furnace thus disturbing the flow of gas and pellets. Therefore, to tackle the above-mentioned issues, an understanding of deposit formation mechanism is of crucial importance. This study was conducted with the objective of addressing the effect of disintegrated iron-ore pellet dust on deposit formation and the mechanisms behind deposition (slagging) in the grate-kiln process. A comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal- fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale setup. Fly ash particles and short-term deposits were characterized and deposition was addressed in Part I of this study. In light of the experimental observations (Part I) and the thermochemical equilibrium calculations (Part II), a scheme of ash transformation during the iron-ore pelletizing process was proposed. The dissolution of hematite particles into the Ca-rich-aluminosilicate melt (from the coal-ash constituents) decreased the viscosity and resulted in the formation of stronger (heavily sintered) deposits. Overall, this pilot-scale work forms part of a wider study which aims at deepening the understanding of ash transformation phenomena during the large-scale pelletizing process.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering Chemical Engineering Metallurgy and Metallic Materials Chemical Process Engineering
Research subject
Energy Engineering; Chemical Technology; Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-69019 (URN)10.1016/j.fuproc.2018.05.005 (DOI)000447580600020 ()2-s2.0-85047214684 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-05 (johcin) 

Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2019-01-18Bibliographically approved
Nyberg, E., Mouzon, J., Grahn, M. & Minami, I. (2017). Formation of Boundary Film from Ionic Liquids Enhanced by Additives. Applied Sciences, 7(5), Article ID 433.
Open this publication in new window or tab >>Formation of Boundary Film from Ionic Liquids Enhanced by Additives
2017 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 7, no 5, article id 433Article in journal (Refereed) Published
Abstract [en]

Room temperature ionic liquids (RTILs) have several properties that make them interesting candidates as base fluids for extreme conditions. However, a lack of compatibility with tribo-improving additives combined with an often overly aggressive nature is limiting their use as base fluids. To overcome these drawbacks, hydrocarbon-imitating RTIL base fluids have recently been developed. In this study, the effects of several common additives in the novel RTIL (P-SiSO) were examined by laboratory tribotesting. A reciprocating steel-steel ball-on-flat setup in an air atmosphere was used, where the lubricant performance was evaluated over a range of loads and temperatures. Surface analyses after testing were carried out using optical profilometry, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Neat P-SiSO displayed high performance in the tribotests. At an elevated load and temperature, a shift in lubrication mode was observed with an accompanying increase in friction and wear. Surface analysis revealed a boundary film rich in Si and O in the primary lubrication mode, while P was detected after a shift to the secondary lubrication mode. An amine additive was effective in reducing wear and friction under harsh conditions. The amine was determined to increase formation of the protective Si–O film, presumably by enhancing the anion activity.

Place, publisher, year, edition, pages
Basel: MDPI, 2017
Keywords
gränsskiktssmörjning, jonvätska, friktion, nötning, tribologi
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Chemical Process Engineering
Research subject
Machine Elements; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-63211 (URN)10.3390/app7050433 (DOI)000404449000002 ()2-s2.0-85018920929 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-05-10 (rokbeg)

Available from: 2017-05-02 Created: 2017-05-02 Last updated: 2018-11-26Bibliographically approved
Melk, L., Mouzon, J., Turon-Vinas, M., Akhtar, F., Antti, M.-L. & Anglada, M. (2016). Surface microstructural changes of Spark Plasma Sintered Zirconia after grinding and annealing (ed.). Ceramics International, 42(14), 15610-15617
Open this publication in new window or tab >>Surface microstructural changes of Spark Plasma Sintered Zirconia after grinding and annealing
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2016 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 42, no 14, p. 15610-15617Article in journal (Refereed) Published
Abstract [en]

Spark plasma sintered zirconia (3Y-TZP) specimens have been produced of 140 nm 372 nm and 753 nm grain sizes by sintering at 1250 C, 1450 C and 1600 C, respectively. The sintered zirconia specimens were grinded using a diamond grinding disc with an average diamond particle size of about 60 µm, under a pressure of 0.9 MPa. The influence of grinding and annealing on the grain size has been analysed. It was shown that thermal etching after of ruff grinding of specimens at 1100 C for one hour induced an irregular surface layer of about a few hundred nanometres in thickness of recrystallized nano-grains, independently of the initial grain size. However, if the ground specimens were exposed to higher temperature, e.g. annealing at 1575 °C for one hour, the nano-grain layer was not observed and the final grain size was similar to that achieved by the same heat treatments on carefully polished specimens. Therefore, by appropriate grinding and thermal etching treatments, nanograined surface layer can be obtained which increases the resistance to low temperature degradation.

National Category
Other Materials Engineering Chemical Process Engineering
Research subject
Engineering Materials; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-7853 (URN)10.1016/j.ceramint.2016.07.014 (DOI)000382269800061 ()2-s2.0-84994234920 (Scopus ID)64656baf-1342-4451-92db-db1edc6357de (Local ID)64656baf-1342-4451-92db-db1edc6357de (Archive number)64656baf-1342-4451-92db-db1edc6357de (OAI)
Note

Validerad; 2016; Nivå 2; 20160331 (latmel)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Garcia, G., Cardenas, E., Cabrera, S., Hedlund, J. & Mouzon, J. (2016). Synthesis of zeolite Y from diatomite as silica source (ed.). Microporous and Mesoporous Materials, 219, 29-37
Open this publication in new window or tab >>Synthesis of zeolite Y from diatomite as silica source
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2016 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 219, p. 29-37Article in journal (Refereed) Published
Abstract [en]

Bolivian diatomite was successfully used as a silica source for the synthesis of zeolite Y. Prior to synthesis, the diatomite was leached with sulfuric acid to remove impurities and aluminum sulfate was used as an aluminum source. The raw materials were reacted hydrothermally at 100 °C in water with sodium hydroxide and different Na2O/SiO2 ratios were investigated. The final products were characterized by scanning electron microscopy, X-ray diffraction, gas adsorption and inductively coupled plasma-atomic emission spectroscopy. Diatomites originating from different locations and therefore containing different types and amounts of minerals and clays as impurities were investigated. After optimization of synthesis time, zeolite Y with low SiO2/Al2O3 ratio (3.0–3.9) was obtained at a high yield for high alkalinity conditions (Na2O/SiO2 = 0.85–2.0). Lower Na2O/SiO2 ratios resulted in incomplete dissolution of diatomite and lower yield. Nevertheless, decreasing alkalinity resulted in a steady increase of the SiO2/Al2O3 ratio in zeolite Y. Consequently, it was possible to synthesize almost pure zeolite Y with a SiO2/Al2O3 ratio of 5.3 for a Na2O/SiO2 ratio of 0.6, albeit at a low yield. In this respect, diatomite enables the synthesis of high silica zeolite Y and behaves similarly to colloidal silica in traditional syntheses, with both sources of silica having in common a high degree of polymerization. Interestingly, the presence of minerals and clays in the starting diatomite had marginal effects on the outcome of the synthesis. However, their dissolution resulted in presence of calcium and magnesium in the zeolite Y crystals. Finally, overrun of all investigated compositions resulted in the formation of zeolite P nucleating and growing onto dissolving zeolite Y crystals, which was shown to be triggered when aluminum was completely depleted at high alkalinity

National Category
Chemical Process Engineering
Research subject
Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-12926 (URN)10.1016/j.micromeso.2015.07.015 (DOI)000363353800004 ()2-s2.0-84938800962 (Scopus ID)c129064d-2137-4d37-b6c4-b3ffd68a2c1b (Local ID)c129064d-2137-4d37-b6c4-b3ffd68a2c1b (Archive number)c129064d-2137-4d37-b6c4-b3ffd68a2c1b (OAI)
Note

Validerad; 2015; Nivå 2; 20150819 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2019-10-11Bibliographically approved
Mouzon, J., Bhuiyan, I. U. & Hedlund, J. (2016). The structure of montmorillonite gels revealed by sequential cryo-XHR-SEM imaging (ed.). Paper presented at . Journal of Colloid and Interface Science, 465, 58-66
Open this publication in new window or tab >>The structure of montmorillonite gels revealed by sequential cryo-XHR-SEM imaging
2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 465, p. 58-66Article in journal (Refereed) Published
Abstract [en]

Imaging by extreme high resolution-scanning electron microscopy (XHR-SEM) with a monochromated and decelerated beam was applied on 5% (wt/wt) Na and Ca-montmorillonite gels frozen by high pressure freezing (HPF). In order to visualize the three-dimensional structure and the contacts between clay platelets, a new approach was developed. It consists in recording a sequence of micrographs on a region of interest during controlled sublimation. This simple method allows to rewind and to relate the instantaneous configuration between several particles to their original position in the hydrated state. Consequently, aggregates of parallel platelets (i.e. curved tactoids) were present in the Ca-sample and the instantaneous position of these aggregates in the course of sedimentation was revealed. The Na-sample consisted of a continuous network of flexible platelets sharing mostly face-to-face (FF) contacts caused by jamming at the relatively high concentration of the suspension (5% (wt/wt)), which was above the gel transition. Yet individual platelets belonging to the smallest size fraction were observed to be fully dispersed within the entangled structure, which confirmed the repulsive character of the gel. Substructures consisting of several platelets connected by FF-associations were also evidenced. The origin and potential impact of such substructures on the occurrence of the sol–gel transition and birefringence are discussed.

National Category
Chemical Process Engineering
Research subject
Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-8088 (URN)10.1016/j.jcis.2015.11.031 (DOI)000367770100009 ()26641566 (PubMedID)2-s2.0-84948158099 (Scopus ID)68763d65-c146-42ff-8480-1e85e3854ece (Local ID)68763d65-c146-42ff-8480-1e85e3854ece (Archive number)68763d65-c146-42ff-8480-1e85e3854ece (OAI)
Note
Validerad; 2015; Nivå 2; 20151130 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karimi, S., Korelskiy, D., Yu, L., Mouzon, J., Khodadadi, A. A., Mortazavi, Y., . . . Hedlund, J. (2015). A simple method for blocking defects in zeolite membranes (ed.). Paper presented at . Journal of Membrane Science, 489, 270-274
Open this publication in new window or tab >>A simple method for blocking defects in zeolite membranes
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2015 (English)In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 489, p. 270-274Article in journal (Refereed) Published
Abstract [en]

The abatement of defects in zeolite membranes is essential for achieving high selectivity. In the present work, a simple and effective method for blocking defects in ultra-thin (ca. 0.5 μm) MFI zeolite membranes has been developed. The method is based on deposition of an ultra-thin (∼15 nm) layer of amorphous silica on the top surface of the membrane. Permporometry data indicated that the amount of defects, especially defects larger than 4 nm, in the membranes was significantly reduced after the modification. In mixture separation experiments, the CO2/H2 separation factor increased dramatically after blocking the defects in a defective membrane that was selected for the experiments. For instance, at 263 K and 9 bar feed pressure, the CO2/H2 separation factor increased from 8.5 to 36 after modification of the membrane, whereas the CO2 flux only decreased by ca. 40%.

National Category
Chemical Process Engineering
Research subject
Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-7226 (URN)10.1016/j.memsci.2015.04.038 (DOI)000355209300032 ()2-s2.0-84938496874 (Scopus ID)58f3c157-abda-4f09-9571-e3ea491e7be5 (Local ID)58f3c157-abda-4f09-9571-e3ea491e7be5 (Archive number)58f3c157-abda-4f09-9571-e3ea491e7be5 (OAI)
Note
Validerad; 2015; Nivå 2; 20150413 (dankor)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zhou, H., Mouzon, J., Farzaneh, A., Antzutkin, O., Grahn, M. & Hedlund, J. (2015). Colloidal Defect-Free Silicalite-1 Single Crystals: Preparation, Structure Characterization, Adsorption, and Separation Properties for Alcohol/Water Mixtures (ed.). Paper presented at . Langmuir, 31(30), 8488-8494
Open this publication in new window or tab >>Colloidal Defect-Free Silicalite-1 Single Crystals: Preparation, Structure Characterization, Adsorption, and Separation Properties for Alcohol/Water Mixtures
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2015 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 30, p. 8488-8494Article in journal (Refereed) Published
Abstract [en]

In this work, colloidal silicalite-1 single crystals are for the first time synthesized using fluoride as mineralizing agent at near neutral pH. SEM, TEM, DLS, XRD, solid-state 29Si MAS NMR, and adsorption/desorption experiments using nitrogen, water, n-butanol, and ethanol as adsorbates were used to characterize the crystals. The single crystals have a platelike habit with a length of less than 170 nm and an aspect ratio (length/width) of about 1.2, and the thickness of the crystals is less than 40 nm. Compared with silicalite-1 crystals grown using hydroxide as mineralizing agent, the amount of structural defects in the lattice is significantly reduced and the hydrophobicity is increased. Membrane separation and adsorption results show that the synthesized defect-free crystals present high selectivity to alcohols from alcohol/water mixtures. The n-butanol/water adsorption selectivities were ca. 165 and 14 for the defect-free crystals and a reference sample containing defects, respectively, illustrating the improvement in n-butanol/water selectivity by eliminating the polar silanol defects.

National Category
Chemical Process Engineering Physical Chemistry
Research subject
Chemical Technology; Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-7846 (URN)10.1021/acs.langmuir.5b02520 (DOI)000359278000034 ()2-s2.0-84938674785 (Scopus ID)64403f34-d43d-43de-9d6f-b5e17b81fbdc (Local ID)64403f34-d43d-43de-9d6f-b5e17b81fbdc (Archive number)64403f34-d43d-43de-9d6f-b5e17b81fbdc (OAI)
Note
Validerad; 2015; Nivå 2; 20150725 (magr)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4582-0902

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