| 1. |
- Alakangas, Lena, et al.
(author)
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Project: ERA-MIN project "Tools for sustainable gold mining in EU"
- 2014
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Other publication (pop. science, debate, etc.)abstract
- This research identifies and evaluates environmental impacts and economical challenges of gold mining in Finland, Sweden, Portugal, Romania, Poland and Ireland. The focus of this project is in gold exploration, mineral processing, water treatment, waste management, environmental monitoring, risk assessment and socio-economic impacts of gold mining. Finasieras av Vinnova
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| 2. |
- Hamberg, Roger, et al.
(author)
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Cementation of cyanidation tailings : Effects on the release of As, Cu, Ni and Zn
- 2018
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In: Proceedings of the 11th ICARD | IMWA | MWD Conference. - : International Mine Water Association (IMWA). ; , s. 617-622
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Conference paper (peer-reviewed)abstract
- Maintaining saturated conditions in two cemented paste backfill (CPB)-mixtures (1-3 wt.% of binders) based on cyanidation tailings was vital for reducing the pyrrhotite oxidation rate and the release of Cu, Ni and Zn. The opposite was true for As, that desorbed from Fe-precipitates and formed soluble Ca-arsenates. Flooding of CPB-fillings could be a long-term process, where unsaturated zones can form within CPB-masses. At this stage, leachates from CPBs (1 wt. %), became acidic, causing As-release to decrease but the opposite for Cu. In CPBs (3wt. %), As-release was unaltered but the Zn-release increased as binder-related Zn-phases dissolved in alkaline conditions.
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| 3. |
- Hamberg, Roger
(author)
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Cementation of cyanidation tailings – effects on the release of As, Cu, Ni and Zn
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- Knowledge about mineralogy and chemical composition in sulfidic tailings is essential to predict how tailings management may affect the future leachate quality. At a gold mine in the north of Sweden, gold was extracted from inclusions in arsenopyrite and pyrrhotite by the use of cyanide. Sulfides in the ore dissolved to a large extent during the cyanide leaching process causing sulfide-related elements such as As, Cu, Ni and Zn to be mobilized to a various extent. In a subsequent water treatment process, a significant proportion of As and Cu was captured in secondary formed Fe-precipitates. Large proportions of water-soluble Ni- and Zn-species in tailings suggested that this treatment was insufficient to reduce the mobility of Ni and Zn. Maintaining oxidized, neutral conditions is of major importance for the immobility of As, Cu, Ni and Zn during further management of the cyanidation tailings (CT).Part of the CT were planned to be managed in underground cavities by the use of a cemented paste backfill (CPB) -application. In CPB, a monolithic mass is formed as tailings are mixed with small proportions (4-7 weight %) of pozzolanic materials and backfilled into underground excavated areas. Using a CPB-application may decrease the sulphide oxidation rate, reducing exposure of mineral surfaces to oxygen and increasing water saturation levels within the material. In this study, CT was mixed with binders (1-3 wt. %) for the formation of a low-strength (0.2 Mpa) CT-CPB-mass. These mixtures were stored at moisturized conditions and subsequently subjected to oxidized and flooded conditions in a laboratory-based study. During short-term storing, high water saturation levels were preserved in the CT-CPB-mixtures, but, sulfide oxidation still progressed, and the release of Zn, Cu, and Ni was still lower compared to that in CT. The opposite was true for As, probably due to a desorption from Fe-precipitates. The desorbed As was subsequently incorporated into less acid-tolerant species (i.e. Ca-arsenates and As bonded to cementitious phases) in the CT-CPB:s, that readily dissolved and released more As compared to that in CT.A complete flooding of CPB-filled workings may take a long time to be reached. During this transition period, zones with low levels of water saturation forms in the CPB-monoliths, which could increase the sulphide oxidation rate, lower pH and dissolve the cementitious binders. In this study, strength decreased along with the water saturation levels in the CPB-mixtures, due to a more extensive pyrrhotite oxidation. A minimal proportion (1 wt. %) of binders did not suppress Cu and As leaching during flooding, but Ni and Zn-leaching were still lower than from CT. In the CT-CPB:s, proportions of As, Cu, Ni and Zn associated with cementitious phases increased in tandem with the fraction of binders. Using higher binder proportions in the CPB, as water saturation levels were lowered, substantially increased the Zn-release while there was an insignificant change in the As-release, and substantially lower Cu- and Ni-release. Pyrrhotite oxidation proceeded in the CT-CPB-mixtures independent of water saturation level. So, increasing binder proportion in a CPB does not necessary mean that trace metals are more stabilized, due to the formation of acid-intolerant fractions. Results from this study, pinpoints the importance of having knowledge about trace element distribution and mineral assemblage in tailings before management methods are chosen and implemented.
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| 4. |
- Hamberg, Roger
(author)
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Characterization and solidification of arsenic-rich cyanided tailings
- 2014
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Licentiate thesis (other academic/artistic)abstract
- Information on the occurrence of As species and iron sulphide minerals in tailings is essential for predicting therelease of As over extended period of time. Tailings originating from a goldmine in northern Sweden with low content of trace elements except for As were used for this purpose. The dominating sulphides were pyrrhotite and arsenopyrite. The samples used in the study were post-cyanided, tailings slurries treated with Fe2(SO4)3 and H2O2 to form arsenates and Fe-hydrates for effective As-immobilization. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed Fe-hydrates. A minor part of the As retained in the tailings was assumed to be As (III)-species. Weathering cell tests (WCT) involving 32 weekly cycles of wetting and air exposure were conducted to assess the effect of weathering on the stability of As in the tailings. As-bearing Fe-hydrates remained intact during the early stages of the WCT; the low release of As during this period was probably due to the dissolution of solubleAs(III)-phases. During the later stages of the WCT, the release of As, Fe and S increased due to pyrrhotite oxidation and the destabilization of As-bearing Fe-hydrates. The majority of the originally present As was still associated with the tailings by the end of the test, but additional pyrrhotite oxidation with the pH falling to >3 could further destabilize these As-bearing Fe-hydrates. In the second part of the study,cyanided tailings were converted into a monolith by using a method called cemented paste backfill (CPB). Two mixtures of CPB were tested; CE with 1 wt. % of cement and CE-FA consisting 2 weight (wt.) % of cement together with 1 wt. % of biofuel fly ash. The stability of As in CPB-masses andun-amended tailings were evaluated using tank leaching tests (TLT) and WCT: s. TheTLT results showed that the CPB mixtures were not suitable for use inunderground backfilling because the As content of the CPB leachates increasedcontinuously over the course of the tests. The proportion of binders inCPB-materials is usually 3-7% because such loadings are required to create amonolithic mass that physically and chemically stabilizes arsenic species intailings. The addition of small quantities of binders in CE and CE-FA maytherefore have been insufficient to ensure that the monoliths were highly saturated, which is required to prevent the transport of oxygen and water through the CPB material. In the WCT, crushed CPB materials were used and the addition of binders caused only a minor increase in the leaching of As relative to that seen with unmodified tailings. The addition of binders has re-located a minor proportion of As in As-bearing Fe-hydrates into less acid-tolerant species. During the later stages of the WCTs, the CPB mixtures were treated with acid in order to consume the buffering minerals and simulate the formation of acid mine drainage (AMD). When acid was added to crushed CPB-materials, As-release increased due to the dissolution of Fe-hydrates. The addition of binders into tailings could pose more resistance to sulphide oxidation, which in turn means that the stability of As-bearing Fe-hydrates could be prolonged on long term. Results from the WCT suggested that the addition of low proportions of binders could have a positive effect on As-leaching in a long term perspective. A relatively new method called “Surfacepaste disposal” (SPD), where mixtures of low proportions of binders and tailings is placed as a cover on the un-amended tailings has shown promising results in terms of decreasing As-leaching and the generation of AMD. Future research will, therefore, focus on the stability of As in SPD-applications.
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| 5. |
- Hamberg, Roger, et al.
(author)
-
Lowering the water saturation level in cemented paste backfill mixtures : Effect on the release of arsenic
- 2017
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In: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 112, s. 84-91
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Journal article (peer-reviewed)abstract
- The Cemented Paste Backfill (CPB) method allows the mixing of dewatered tailings slurries with cementitious binders to backfill excavated underground workings. After mine closure, CPB workings are permanently flooded by rising groundwater. This flooding is considered beneficial for reducing the risk of acid generation associated with CPB containing sulphide minerals. In general, CPB workings are slowly flooded and the process may lead to regions with a low degree of water saturation to form within the CPB. This in turn, may increase oxygen ingress in the CPB, thereby prolonging oxidation of the minerals. To investigate the environmental impact of this oxidation, tailings containing elevated concentrations of arsenic (As) and pyrrhotite were handled via CPB. In this study, CPB mixtures containing 1–3 wt.% of cementitious binders and tailings was studied. The water saturation level in the CPB-mixtures was lowered as curing time extended. In mimicked flooded conditions, the mobility of As in the CPB mixtures was correlated with As-bearing cementitious phases that are sensitive to a reduction in the pH. In CPB-mixtures with lower proportions of binders, cementitious As-phases dissolved while the water saturation level decreased to form more stable As-phases. Increasing binder fractions, most of the cementitious As-phases persisted in the CPB while water saturation levels were lowered and release of As increased. Regardless of curing conditions, managing these tailings via the CPB method yielded increased mobility of As compared with that in the unmodified tailings; this resulted possibly from the formation of less acid-tolerant As species.
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| 6. |
- Hamberg, Roger, et al.
(author)
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Release of arsenic from cyanidation tailings
- 2016
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In: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 93, s. 57-64
-
Journal article (peer-reviewed)abstract
- At a gold mine in northern Sweden, gold occurring as inclusions in pyrrhotite and arsenopyrite is leached by cyanidation of the ore. The main sulphide minerals in the ore are pyrrhotite and arsenopyrite. Effluents from the cyanidation process are treated with Fe2(SO4)3 to form Fe-precipitates suitable for the co-precipitation of As. The aim of this study was to perform static and kinetic leaching tests on the ore and tailings to define geochemical processes governing As mobility. Sequential leaching tests suggested that the majority of dissolved As deriving from the sulphide fraction in the ore was incorporated in newly formed Fe-precipitates in the tailings. The mobility of As in the tailings was therefore mainly dependent on the stability of these As-bearing Fe-precipitates. Weathering cell tests (WCT) involving 31 weekly cycles of wetting and air exposure were conducted to assess the stability of the As in the tailings under accelerated weathering conditions. The first stage of the WCT was characterized by a pH ≈ 5 and low As leaching, probably driven by the dissolution of amorphous Fe-As species. In the second stage of the WCT, leaching of Fe, S and As increased and the pH decreased to <3.5. An increase of the leachate’s molar Fe/S-ratio suggested that pyrrhotite oxidation was occurring. The falling pH destabilized As-bearing Fe-precipitates, causing further As release. The total As release during the WCT corresponded to only a small proportion of the tailings’ total As content. The accelerated As-leaching observed towards the end of the WCT could thus indicate that its release could increase progressively over time.
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| 7. |
- Hamberg, Roger, et al.
(author)
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The formation of unsaturated zones within cemented paste backfill mixtures : Effects on the release of copper, nickel, and zinc
- 2018
-
In: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 25:21, s. 20809-20822
-
Journal article (peer-reviewed)abstract
- Flooding of cemented paste backfill (CPB) filled mine workings is, commonly, a slow process and could lead to the formation of unsaturated zones within the CPB-fillings. This facilitates the oxidation of sulfide minerals, and thereby increases the risk of trace-metal leaching. Pyrrhotitic tailings from a gold mine (CT), containing elevated concentrations of Ni, Cu and Zn, were mixed with cement and/or fly ash (1-3 wt. %) to form CT-CPB-mixtures. Pyrrhotite oxidation progressed more extensively during unsaturated conditions, where acidity resulted in dissolution of the Ni, Cu, and Zn associated with amorphous Fe-precipitates and/or cementitious phases. The establishment of acidic, unsaturated conditions in CT-CBP:s with low fractions (1 wt. %) of binders increased the Cu-release (to be higher than that from CT), owing to the dissolution of Cu-associated amorphous Fe-precipitates. In CT-CPB:s with relatively high proportions of binder, acidity from pyrrhotite oxidation was buffered to a greater extent. At this stage, Zn-leaching increased due the occurrence of fly ash-specific Zn-species soluble in alkaline conditions. Irrespective of binder proportion and water saturation level, the Ni- and Zn-release were lower, compared to that in CT. Fractions of Ni, Zn, and Cu associated with acid-soluble phases or amorphous Fe-precipitates, susceptible to remobilization under acidic conditions, increased in tandem with binder fractions. Pyrrhotite oxidation occurred irrespective of the water saturation level in the CPB-mixtures. That in turn, poses an environmental risk, whereas a substantial proportion of Ni, Cu and Zn were associated with acid-soluble phases.
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| 8. |
- Hamberg, Roger, et al.
(author)
-
The release of arsenic from cyanidation tailings
- 2016
-
In: Arsenic Research and Global Sustainability. - London : CRC Press. - 9781315629438 ; , s. 201-202
-
Conference paper (peer-reviewed)abstract
- Tailings from a gold mine containing 1000 mg/kg of As were used to predict the release of As over an extended period of time. Post-cyanide mine processes were aiming to form arsenates and Fe-hydrates for effective As-immobilization. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed Fe-hydrates. Weathering Cell Tests (WCT) were conducted to assess the effect of weathering on the stability of As in the tailings. As-bearing Fe-hydrates remained intact during the early stages of the WCT. During later stages of the WCT, the release of As, Fe and S increased due to pyrrhotite oxidation and the destabilization of As-bearing Fe-hydrates. Low proportions of As was released in WCT, but additional pyrrhotite oxidation as pH falling to < 3 could further destabilize As-bearing Fe-hydrates
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| 9. |
- Hamberg, Roger, et al.
(author)
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The use of low binder proportions in cemented paste backfill : Effects on As-leaching
- 2015
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In: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 78, s. 74-82
-
Journal article (peer-reviewed)abstract
- Gold is extracted by cyanide leaching from inclusions in arsenopyrite at a mine in the north of Sweden. The major ore mineral assemblage consists of pyrrhotite and arsenopyrite–loellingite. Arsenopyrite is assumed to be oxidized during cyanidation and the stability of secondary As-phases needs to be assessed. One way of managing such tailings is to convert them into a monolithic mass by using a method called cemented paste backfill (CPB). In CPB, tailings are traditionally mixed with water (typically 25% by weight) and small amounts (3–7%) of binders, and backfilled into excavated underground areas. To investigate the release of arsenic (As) from CPB prepared from As-rich tailings, tailings containing approx. 1000 ppm of As, mainly in the form of As-bearing iron (Fe)-precipitates (FEP), were mixed with small quantities (1–3%) of biofuel fly ash (BFA), ordinary cement, and water to produce monolithic CPB masses. CPB-recipes were designed to meet the strength demand of 200 kPa, stated by the mine operators. Tank leaching tests (TLT) and the weathering cell test (WCT) were used to compare the leaching behavior of As in unmodified tailings and CPB-materials. Results from the leaching tests (TLT and WCT) showed that the inclusion of As-rich tailings into a cementitious matrix increased leaching of As. This behavior could partially be explained by an increase of pH where As sorbed to FEPs becomes unstable. In the CPB mixtures, small (>1%) proportions of the total As in the solid material was released from less acid-tolerant species (i.e. Ca-arsenates and As bonded to cementitious phases). Unmodified tailings generated an acidic environment in flooded conditions at which As-bearing FEPs were stable. Acid was added to the crushed CPB materials during later stages of the WCTs to mimic the effects of weathering. This increased the leaching of Fe and had minor effects on that of As but did not affect S-leaching.
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| 10. |
- Hamberg, Viggo, et al.
(author)
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Anti-Ro52 positivity is associated with progressive interstitial lung disease in systemic sclerosis-an exploratory study
- 2023
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In: Arthritis Research & Therapy. - : BioMed Central (BMC). - 1478-6362 .- 1478-6354. ; 25, s. 1-13
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Journal article (peer-reviewed)abstract
- Background: Interstitial lung disease (ILD) is the most common cause of death in patients with systemic sclerosis (SSc). Prognostic biomarkers are needed to identify SSc-ILD patients at risk for progressive pulmonary fibrosis. This study investigates autoantibodies measured in bronchoalveolar lavage (BAL) fluid and in serum in reference to the clinical disease course of SSc-ILD.Methods: Fifteen patients with new onset SSc-ILD underwent bronchoscopy. Autoantibody levels were analyzed using addressable laser bead immunoassay from BAL fluid and the serum. In a separate longitudinal cohort of 43 patients with early SSc-ILD, autoantibodies in serum were measured at baseline and pulmonary function tests were performed at least 2 times over the course of at least 2 or more years. Linear mixed effect models were created to investigate the relationship between specific autoantibodies and progression of SSc-ILD. Finally, lung tissue from healthy controls and from subjects with SSc was analyzed for the presence of the Ro52 antigen using immunohistochemistry.Results: Among SSc-ILD patients who were positive for anti-Ro52 (N = 5), 3 (60%) had enrichment of anti-Ro52 in BAL fluid at a ratio exceeding 50x. In the longitudinal cohort, 10/43 patients (23%) were anti-Ro52 positive and 16/43 (37%) were anti-scl-70 positive. Presence of anti-Scl-70 was associated with a lower vital capacity (VC) at baseline (-12.6% predicted VC [%pVC]; 95%CI: -25.0, -0.29; p = 0.045), but was not significantly associated with loss of lung function over time (-1.07%pVC/year; 95%CI: -2.86, 0.71; p = 0.230). The presence of anti-Ro52 was significantly associated with the loss of lung function over time (-2.41%pVC/year; 95% CI: -4.28, -0.54; p = 0.013). Rate of loss of lung function increased linearly with increasing anti-Ro52 antibody levels (-0.03%pVC per arbitrary units/mL and year; 95%CI: -0.05, -0.02; p < 0.001). Immunohistochemical staining localized the Ro52 antigen to alveolar M2 macrophages in peripheral lung tissue both in subjects with and without SSc.Conclusions: This study suggests that antibodies targeting Ro52 are enriched in the lungs of patients with new-onset SSc-ILD, linking Ro52 autoimmunity to the pulmonary pathology of SSc. Clinical and immunohistochemical data corroborates these findings and suggest that anti-Ro52 may serve as a potential biomarker of progressive SSc-ILD.
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| 11. |
- Jia, Yu, et al.
(author)
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Variation of green liquor dregs from different pulp and paper mills for use in mine waste remediation
- 2019
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In: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 26:30, s. 31284-31300
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Journal article (peer-reviewed)abstract
- The geotechnical, chemical, and mineralogical properties of green liquor dregs (GLDs) generated as byproducts from five paper mills were investigated to assess their buffering and heavy metal immobilization capacities and their roles as water and oxygen barriers. One type of GLD was further studied to test the effects of the retrieval process and the storage, drying, and hydration of GLD. The high water retention capacity of the GLDs is valuable for limiting O2diffusion. Laboratory results showed that the GLDs had hydraulic conductivities of 3.7 × 10−9–4.6 × 10−8 m/s and varied regularly in plasticity. The chemical and mineralogical compositions of the GLDs varied greatly, reflecting the raw material used to produce paper and the process used to retrieve GLDs. Although they had high total heavy metal contents, none of the leached elements from the GLDs (L/S 10 cm3/kg) exceeded the European Union’s limits for landfills of non-hazardous waste. The GLDs exhibited high buffering capacities. In a supplementary test, the buffering capacities varied (0.0041–0.0114 M H+/g GLD) over 72 d after acid was added to the GLD. Changing the filtration process did not greatly affect the GLDs’ properties but mainly affected the hydraulic conductivity, total heavy metal contents and sulfur content. Analyzing the storage of GLDs is necessary in the mining industry because remediation measures require large amounts of material over short periods. The buffering capacity of the dried GLD decreased slightly. The effect of dewatering caused by the mixing of 2% Na-lignosulfate with GLD (w/w) was low.
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| 12. |
- Kumpiene, Jurate, et al.
(author)
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Leaching of arsenic, copper and chromium from thermally treated soil
- 2016
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In: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 183:3, s. 460-466
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Journal article (peer-reviewed)abstract
- Thermal treatment, if properly performed, is an effective way of destroying organic compounds in contaminated soil, while impact on co-present inorganic contaminants varies depending on the element. Leaching of trace elements in thermally treated soil can be altered by co-combusting different types of materials. This study aimed at assessing changes in mobility of As, Cr and Cu in thermally treated soil as affected by addition of industrial by-products prior to soil combustion. Contaminated soil was mixed with either waste of gypsum boards, a steel processing residue (Fe3O4), fly ash from wood and coal combustion or a steel abrasive (96.5% Fe0). The mixes and unamended soil were thermally treated at 800 °C and divided into a fine fraction <0.125 mm and a coarse fraction >0.125 mm to simulate particle separation occurring in thermal treatment plants. The impact of the treatment on element behaviour was assessed by a batch leaching test, X-ray absorption spectroscopy and dispersive X-ray spectrometry. The results suggest that thermal treatment is highly unfavourable for As contaminated soils as it increased both the As leaching in the fine particle size fraction and the mass of the fines (up to 92%). Soil amendment with Fe-containing compounds prior to the thermal treatment reduced As leaching to the levels acceptable for hazardous waste landfills, but only in the coarse fraction, which does not justify the usefulness of such treatment. Among the amendments used, gypsum most effectively reduced leaching of Cr and Cu in thermally treated soil and could be recommended for soils that do not contain As. Fly ash was the least effective amendment as it increased leaching of both Cr and As in majority of samples.
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| 13. |
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| 14. |
- Vahlne, Jan-Erik, et al.
(author)
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Management under uncertainty : the unavoidable risk-taking
- 2017
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In: Multinational Business Review. - 1525-383X. ; 25:2, s. 91-109
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Journal article (peer-reviewed)abstract
- Purpose - Accentuating the concept of management under uncertainty in the Uppsala internationalization process model, the purpose of this paper is to develop a model for describing how managers act while keeping uncertainty at an acceptable level. Design/methodology/approach - The authors perform two empirical studies to underpin the model they construct. First, a survey of 309 chief executive officers and chief financial officers in large, publicly listed international firms in the Nordic region on managerial risk perceptions and, second, a case study of Volvo Car Corporation and its endeavors when developing new car models for the Chinese market on a new platform - a process characterized by unprecedented uncertainty. Findings - The proposed model describing managers' behavior under uncertainty contains elements such as adjusting/proceeding in small steps, reducing uncertainty via learning, building relationships with important parties in the environment to avoid unforeseen changes and re-dos (i.e. starting all over again) and, perhaps most important, acting despite uncertainty. Originality/value - The paper highlights a central, though forgotten, concept of the Uppsala internationalization process model, i.e. management under uncertainty, and, thereby, opens a new path for research on how manager behave under the sway of uncertainty.
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| 15. |
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| 16. |
- Vahlne, Jan-Erik, 1941, et al.
(author)
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Management under uncertainty - the unavoidable risk-taking
- 2017
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In: Multinational Business Review. - : Emerald. - 1525-383X. ; 25:2, s. 91-109
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Journal article (peer-reviewed)abstract
- Purpose - Accentuating the concept of management under uncertainty in the Uppsala internationalization process model, the purpose of this paper is to develop a model for describing how managers act while keeping uncertainty at an acceptable level. Design/methodology/approach - The authors perform two empirical studies to underpin the model they construct. First, a survey of 309 chief executive officers and chief financial officers in large, publicly listed international firms in the Nordic region on managerial risk perceptions and, second, a case study of Volvo Car Corporation and its endeavors when developing new car models for the Chinese market on a new platform - a process characterized by unprecedented uncertainty. Findings - The proposed model describing managers' behavior under uncertainty contains elements such as adjusting/proceeding in small steps, reducing uncertainty via learning, building relationships with important parties in the environment to avoid unforeseen changes and re-dos (i.e. starting all over again) and, perhaps most important, acting despite uncertainty. Originality/value - The paper highlights a central, though forgotten, concept of the Uppsala internationalization process model, i.e. management under uncertainty, and, thereby, opens a new path for research on how manager behave under the sway of uncertainty.
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| 17. |
- Wildt, Marie, et al.
(author)
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Treatment with mycophenolate mofetil is associated with improved nailfold vasculature in systemic sclerosis
- 2024
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In: Rheumatology (Oxford, England). - 1462-0332. ; 63:2, s. 385-391
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate the evolution of nailfold capillary density in patients with systemic sclerosis (SSc) in relation to immunosupressive treatment and autoantibodies.METHODS: Prospective study cohort. Consecutive newly diagnosed SSc patients were included into this study who, in a retrospective review, had at least 2 nailfold capillary microscopy (NCM) measurements performed during the first 48 months of follow-up. Capillary density per 3 mm was measured with widefield NCM. Improvement of capillary density per finger and mean capillary density were analysed. Longitudinal measurements of mean capillary density were analysed by generalized estimating equation (GEE).RESULTS: Eighty patients (68 women, 12 men) met the inclusion criteria. The median follow-up time was 27 months. Twenty-eight patients had an improved capillary density in per finger analysis. Mycophenolate mofetil (MMF) was associated with less numbers of fingers that had worsened in capillary density. Anti-topoisomerase antibodies were associated with low mean capillary density. Anti-RNA polymerase III antibodies were associated with improvement and anti-centromere antibodies with worsening of capillary density in per finger analysis. MMF treatment was associated with less steep capillary density decline in a moderated GEE model including presence of anti-topoisomerase antibodies and the interaction of MMF with follow-up time.CONCLUSION: Nailfold capillary density improved over time in a substantial proportion of SSc patients. MMF treatment had a positive impact on the evolution of capillary density in these patients. SSc autoantibody phenotype may affect the capillary density development. The data support previous hypotheses that early immunosuppression may favourably affect vascular regeneration in SSc.
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