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| 2. |
- Allard, Bert, 1945-, et al.
(author)
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Metal Exchangeability in the REE-Enriched Biogenic Mn Oxide Birnessite from Ytterby, Sweden
- 2023
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In: Minerals. - : MDPI. - 2075-163X. ; 13:8
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Journal article (peer-reviewed)abstract
- A black substance exuding from fractures was observed in 2012 in Ytterby mine, Sweden, and identified in 2017 as birnessite with the composition Mx[Mn(III,IV)](2)O-4 center dot(H2O)n. M is usually calcium and sodium, with x around 0.5. The Ytterby birnessite is unique, with M being calcium, magnesium, and also rare earth elements (REEs) constituting up to 2% of the total metal content. The biogenic origin of the birnessite was established in 2018. Analysis of the microbial processes leading to the birnessite formation and the REE enrichment has continued since then. The process is fast and dynamic, as indicated by the depletion of manganese and of REE and other metals in the fracture water during the passage over the precipitation zone in the mine tunnel. Studies of the exchangeability of metals in the structure are the main objective of the present program. Exposure to solutions of sodium, calcium, lanthanum, and iron led to exchanges and altered distribution of the metals in the birnessite, however, generating phases with almost identical structures after the exchanges, and no new mineral phases were detected. Exchangeability was more efficient for trivalent elements (REE) over divalent (calcium) and monovalent (sodium) elements of a similar size (ionic radii 90-100 pm).
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| 3. |
- Allard, Bert, et al.
(author)
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On the formation and metal exchangeability of the rare earth element enriched birnessite from the Ytterby mine, Sweden
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Other publication (other academic/artistic)abstract
- A porous black substance exuding from fractures in an underground tunnel leading to the shaft of the Ytterby mine, Sweden, was observed in 2012 and characterized as a secondary manganese (Mn) oxide in 2015. The oxide was identified in 2017 as a birnessite variety, Mx[Mn(III,IV)]2O4∙(H2O)n where M usually is Ca, Na and x is around 0.5, but the Ytterby birnessite appears to be unique with M being Ca, Mg but also yttrium and rare earth elements (YREE), constituting up to 2% of the metal content. The biogenic origin of the Ytterby birnessite was established in 2018. Studies of the formation of this unique birnessite phase has progressed during 2018-19 with detailed studies of the hydrochemistry of the fracture water as well of the exchangeability of the metals M in the structure: Na, Ca, Fe and La representing the YREE. Exposure to solutions of Na, Ca, Fe, and La, respectively (1 M) led to exchanges and altered distribution of the metals constituting M, with a preference of YREE (trivalent) over Ca (divalent) over Na (monovalent), all of similar ionic radii, as well as higher affinity for YREE over Fe(III), being smaller. Fe(III) did not replace Mn(III) in the structure, despite the fact that their radii are almost identical. No discrete new Fe phase was indicated, and the structure of the birnessite phase was almost identical after exchanges of M, as indicated from XRD. The formation of birnessite in the fracture opening on the tunnel wall appears to be a fast and dynamic process, as indicated by a significant depletion of Mn as well as of YREE in the fracture water during the passage over the precipitation zone, from top to bottom.
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| 4. |
- Bäcklund, Stefan, 1961-
(musician, creator_code:cre_t)
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Du och jag
- 2002
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Artistic work (peer-reviewed)abstract
- CD-inspelning med sångarna Gunnel och Fred SjöbergMedverkande musiker;Lennart Jerlestrand - piano, orgelMagnus Spångberg - keyboardStefan Bäcklund - basJonas Kahnberg - gitarrStefan Gräsberg - perc
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| 5. |
- Cedergren, Stefan, 1982, et al.
(author)
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The effects of grain size and feed rate on notch wear and burr formation in wrought Alloy 718
- 2013
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In: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 67:5-8, s. 1501-1507
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Journal article (peer-reviewed)abstract
- The effect of two different workpiece material grain sizes, 16 and 127 μm, on the depth-of-cut notch wear, chip morphology, and burr formation was studied in a turning operation. A material from the same batch of wrought superalloy Alloy 718 was heat-treated to achieve the two microstructures. The machining was performed at two feed rates, 0.1 and 0.2 mm/revolution. Uncoated cemented carbide tools were used. Both grain size and feed rate were found to influence the chip morphology and the sideflow which were also associated with both the notch wear and the burr formation. The effect of the grain size on the notch wear was larger than that of the feed rate under the tested conditions, with larger grains being more detrimental than smaller ones.
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| 7. |
- Sjöberg, S., et al.
(author)
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Putative Biogenic Signature found in Extremely REE Enriched Black Substance, Ytterby Mine, Sweden
- 2015
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In: Goldschmidt Abstracts.
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Conference paper (peer-reviewed)abstract
- Characterization of a black substance seeping from fractured bedrock in a subterranean tunnel revealed a manganese and calcium bearing substance highly enriched in rare earth elements (REE). This tunnel is dry and at shallow depth and was built to convert the former Ytterby mine, into a fuel deposit for the Swedish Armed Forces. To keep the tunnel dry, groundwater level is kept below its natural level which has resulted in oxidizing conditions in a previously dysoxic or anoxic environment. The deposition of the substance therefore occurs in a dark and moist environment which was exposed to changing redox conditions.Geochemical analysis show that the substance is enriched in REEs with concentrations one to two orders of magnitude higher than in the surrounding rocks. X-ray diffraction spectra indicate that the main component is birnessite. SEM revealed an internal lamination of these Mn-oxides implying an iterative change in production. Previous results show that REE occurrences in Ytterby are localized within pegmatites in the mine. It is thus suggested that Mn colloids, suspended in the local groundwater, work as metal traps and contribute to the mobility of the REEs. The black substance is suspected to act as a sink for these metals in the Ytterby mine area.The influence of microorganisms on the accumulation of Mn-oxides appears to be important. The occurrence of the C31 to C35 extended side chain hopanoids among the identified biomarkers provides evidence of bacterial presence in the depositional environment. The abiotic vs biotic origin of the precipitated manganese was investigated by electron paramagnetic resonance spectroscopy. The substance is composed of two or more components, with one part having a biogenic signature. Ongoing investigations of the microbial communities and the REE accumulation processes include δ13C analysis of the extracted lipids, DNA deep sequencing, quantitative PCR and sequential leaching
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| 8. |
- Sjöberg, Susanne, et al.
(author)
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Rare Earth element enriched birnessite in water-bearing fractures, the Ytterby mine, Sweden
- 2017
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In: Applied Geochemistry. - Amsterdam : Elsevier. - 0883-2927 .- 1872-9134. ; 78, s. 158-171
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Journal article (peer-reviewed)abstract
- Characterization of a black substance exuding from fractured bedrock in a subterranean tunnel revealed a secondary manganese oxide mineralisation exceptionally enriched in rare earth elements (REE). Concentrations are among the highest observed in secondary ferromanganese precipitates in nature. The tunnel is located in the unsaturated zone at shallow depth in the former Ytterby mine, known for the discovery of yttrium, scandium, tantalum and five rare earth elements.Elemental analysis and X-ray diffraction of the black substance establish that the main component is a manganese oxide of the birnessite type. Minor fractions of calcite, other manganese oxides, feldspars, quartz and about 1% organic matter were also found, but no iron oxides were identified. The Ytterby birnessite contains REE, as well as calcium, magnesium and traces of other metals. The REE, which constitute 1% of the dry mass and 2% of the metal content, are firmly included in the mineral structure and are not released by leaching at pH 1.5 or higher. A strong preference for the trivalent REE over divalent and monovalent metals is indicated by concentration ratios of the substance to fracture water. The REE-enriched birnessite has the general formula Mx(Mn3+,Mn4+)2O4·(H2O)n with M = (0.37–0.41) Ca + 0.02 (REE + Y), 0.04 Mg and (0.02–0.03) other metals, and with [Mn3+]/[Mn4+] = 0.86–1.00.The influence of microorganisms on the accumulation of this REE enriched substance is demonstrated by electron paramagnetic resonance spectroscopy. Results show that it is composed of two or more manganese phases, one of which has a biogenic signature. In addition, the occurrence of C31 to C35 extended side chain hopanoids among the identified lipid biomarkers combined with the absence of ergosterol, a fungal lipid biomarker, indicate that the in-situ microbial community is bacterial rather than fungal.
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| 9. |
- Sjöberg, Susanne, et al.
(author)
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REE-Enriched Mn-Oxide Precipitates in Water-Bearing Fractures in the Ytterby Mine, Sweden
- 2016
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In: Mining Meets Water – Conflicts and Solutions. - Freiberg : TU Bergakademie Freiberg, Institute of Mining and Special Civil Engineering. - 9783860125335 ; , s. 346-352
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Conference paper (peer-reviewed)abstract
- The Ytterby mine, Sweden, is known for the discovery of eight elements, including yttrium and five of the rare earth elements (REE). The mine was in operation from 1750 to 1933 and was after closure used as a storage depot for fuel from the 1950s to 1995. A tunnel was opened in the 1950s through the bedrock into the mine to allow access to the storage depot. Recent water monitoring campaigns (20122015) in the mine revealed a black substance (denoted YBS) in some fractures opening into the tunnel. Analysis of the YBS (elemental analysis, phase analysis by XRD, SEM with energy dispersive X-ray spectrometry, IR-and EPR-spectroscopy, preferential leaching at pH 4) showed that the main mineral component of the YBS is the manganese oxide birnessite. Also minor quantities of other less well defined manganese oxides were found, as well as silicates (quartz grains, possibly feldspar grains) and calcite. Birnessite has typically the composition Mx(Mn3+, Mn(2)(4+))O(4)xAq, with M= Na, Ca and x= 0.5. The birnessite component in YBS had a Mn3+/Mn4+ ratio of 1.04/0.96 with M = 0.42 Ca + 0.03 (REE+Y), 0.03 Mg and 0.03 other metals. All of these metals were firmly associated with the structure, since no release was observed at pH 4, except for significant fractions of the total Na, Mg, Ca-contents. Thus, REE+Y correspond to 1% of the total YBS mass and up to 3% of the metal content in the birnessite phase. This corresponds to an REE enrichment factor of the order 106 (YBS-birnessite/ fracture water). Birnessite with a substantial fraction of REE in the lattice has not previously been reported. The formation of birnessite is a microbial process. Identification of the microorganisms present in the Ytterby system is in progress.
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| 10. |
- Abdelrahman, Islam, 1982-, et al.
(author)
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Development of delirium : Association with old age, severe burns, and intensive care
- 2020
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In: Burns. - : Elsevier. - 0305-4179 .- 1879-1409. ; 46:4, s. 797-803
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Journal article (peer-reviewed)abstract
- Background Delirium is defined as a disturbance of attention and awareness that develops over a short period of time, is a change from the baseline, and typically fluctuates over time. Burn care involves a high prevalence of known risk factors for delirium such as sedation, inflammation, and prolonged stay in hospital. Our aim was to explore the extent of delirium and the impact of factors associated with it for adult patients who have been admitted to hospital with burns. Methods In this retrospective study, all adult patients who had been admitted with burns during a four-year period were studied, including both those who were treated with intensive care and intermediate care only (no intensive care). Daily records of the assessment of delirium using the Nursing Delirium Screening Scale (Nu-DESC) were analysed together with age, sex, the percentage of total body surface area burned, operations, and numbers of wound care procedures under anaesthesia, concentrations of plasma C-reactive protein, and other clinical variables. Logistic regression was used to analyse factors that were associated with delirium and its effect on mortality, and linear regression was used to analyse its effect on the duration of hospital stay. Results Fifty-one patients (19%) of the total 262 showed signs of delirium (Nu-DESC score of 2 or more) at least once during their stay in hospital. Signs of delirium were recorded in 42/89 patients (47%) who received intensive care, and in 9/173 (5%) who had intermediate care. Independent factors for delirium in the multivariable regression were: age over 74 years; number of operations and wound care procedures under anaesthesia; and the provision of intensive care (area under the curve 0.940, 95% CI 0.899–0.981). Duration of hospital stay, adjusted for age and burn size, was 13.2 (95% CI 7.4–18.9, p < 0.001) days longer in the group who had delirium. We found no independent effects of delirium on mortality. Conclusion We found a strong association between delirium and older age, provision ofr intensive care, and number of interventions under anaesthesia. A further 5% of patients who did not receive intensive care also showed signs of delirium, which is a finding that deserves to be thoroughly investigated in the future.
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