| 1. |
- Wallinder, D., et al.
(författare)
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Influence of surface treatment of type 304L stainless steel on atmospheric corrosion resistance in urban and marine environments
- 2003
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Ingår i: Corrosion. - : NACE International. - 0010-9312 .- 1938-159X. ; 59:3, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- The influence of surface treatment of Type 304L (UNS S30403) stainless steel on atmospheric corrosion resistance in urban and marine environments was investigated during 2 months and 7 months of exposure. The surface conditions investigated included as-received, pickled, abraded, and bright-annealed samples. The surfaces were investigated before the exposures, and differences in surface composition, polarization resistance, surface roughness, and wettability were observed between the various surface treatments. During the exposures, all samples decreased in weight. Under the present conditions, the as-received samples showed the best performance in the urban environment, whereas the bright-annealed samples showed the best performance in the marine environment. Different effects of surface treatments on atmospheric corrosion resistance in both environments could be explained best by the resulting differences in passive film composition.
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| 2. |
- Alinejadian, Navid, et al.
(författare)
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Progress in additive manufacturing of MoS2-based structures for energy storage applications - A review
- 2022
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Ingår i: Materials Science in Semiconductor Processing. - : Elsevier BV. - 1369-8001 .- 1873-4081. ; 139
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Forskningsöversikt (refereegranskat)abstract
- Investigation of next-generation manufacturing methods for the processing of functional materials and offering products with improved performance/functionalities has always been a challenge in terms of energy efficiency, cost-effectiveness, and eco-friendliness. Additive manufacturing (AM) attributes to rapid prototyping techniques that provide new opportunities to test new concepts and design complex 3D structures from metals, ceramics, and composites. Moreover, as a well-known transition metal dichalcogenide, Molybdenum disulfide (MoS2) is a two-dimensional (2D) material with outstanding electrochemical, physical, and mechanical properties that make it a potential candidate for energy storage electrodes via intercalation of different H+, Li+, Na+, and K+ cations. In this review, we discuss the existing conventional MoS2-processing methodologies and compare them with the novel additive manufacturing processes (especially laser-based powder bed fusion). The authors are convinced that the processing of prominent MoS2-based functional structures by the novel additive manufacturing processes can provide complex structures for different electrochemical applications, particularly for energy conversion/ storage systems.
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| 3. |
- Alinejadian, Navid, et al.
(författare)
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SLM-processed MoS2/Mo2S3 nanocomposite for energy conversion/storage applications
- 2022
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- MoS2-based nanocomposites have been widely processed by a variety of conventional and 3D printing techniques. In this study, selective laser melting (SLM) has for the first time successfully been employed to tune the crystallographic structure of bulk MoS2 to a 2H/1T phase and to distribute Mo2S3 nanoparticles in-situ in MoS2/Mo2S3 nanocomposites used in electrochemical energy conversion/storage systems (EECSS). The remarkable results promote further research on and elucidate the applicability of laser-based powder bed processing of 2D nanomaterials for a wide range of functional structures within, e.g., EECSS, aerospace, and possibly high-temperature solid-state EECSS even in space.
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| 4. |
- Atapour, Masoud, et al.
(författare)
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Corrosion and metal release investigations of selective laser melted 316L stainless steel in a synthetic physiological fluid containing proteins and in diluted hydrochloric acid
- 2020
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 354
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Tidskriftsartikel (refereegranskat)abstract
- The corrosion and metal release characteristics of additively manufactured stainless steels are key factors for their applicability in biomedical applications. The effect of building direction on the microstructure, corrosion behavior and metal release of selective laser melted (SLM) AISI 316L stainless steel were therefore investigated in a protein-rich synthetic body fluid (PBS+BSA, pH 7.3) and in diluted hydrochloric acid (HCl, pH 1.5). A multi-analytical approach was applied to characterize SLM 316L surfaces printed in different building directions (denoted XY and XZ) and a post heat treated SLM surface (XZ-HT) compared with wrought surfaces. All SLM specimens revealed an austenitic microstructure without any amounts of delta-ferrite and without large-angled grain boundaries in contrast to the wrought 316L surface. The building direction strongly affected the grain size distribution due to the temperature gradients in the melt pools. The SLM 316L specimens released initially slightly less Fe, Cr and Ni compared with the wrought 316L specimen. Slightly less metal was released from the heat treated SLM specimen (XZ-HT) specimen compared to the other SLM specimens. Relatively high amounts of released Cr were observed in PBS+BSA, most probably attributed to protein-bound Cr, whereas substantially more Ni was released in HCl compared to PBS+BSA due to pitting corrosion and a reduced surface oxide thickness. The surface oxide composition of as-printed SLM specimens was strongly dependent on the building direction and the post heat treatment, whereas no differences were observed after abrasion either among the SLM specimens or compared with the wrought 316L specimen. Cr became in all cases enriched within the outermost surface oxide in PBS+BSA and strongly enriched in the HCl solution, coupled to a strongly reduced amount of released metals with time. The heat treated SLM specimen (XZ-HT) gained a superior charge transfer resistance, the lowest passive current density, and the highest OCP value among all specimens. In HCl, the SLM specimens showed a lower pitting susceptibility compared to the wrought specimens. No pitting was observed in PBS+BSA. No differences in corrosion or metal release characteristics were observed related to the building direction of abraded SLM specimens.
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| 5. |
- Atapour, Masoud, et al.
(författare)
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Corrosion of Binder Jetting Additively Manufactured 316L Stainless Steel of Different Surface Finish
- 2020
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 167:13
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Tidskriftsartikel (refereegranskat)abstract
- One technique of additive manufacturing is the binder-jetting technique that has the advantages of low costs, printing at room temperature and in air, and no need of a support structure. The aim of this study was to investigate the corrosion behavior of printed 316L surfaces with and without different post surface treatments of blasting and superfinishing. Comparative studies were performed on abraded wrought 316L. Surface topography, porosity, surface oxide composition, and electrochemical characteristics, including pitting corrosion, were investigated at room temperature as a function of post surface treatments in diluted hydrochloric acid at pH 1.5. The blasting and superfinishing treatment significantly reduced the surface roughness and level of surface porosity. Blasting detrimentally affected on the pitting corrosion resistance. The superfinishing process induced an enrichment of chromium in the surface oxide and improved the pitting corrosion resistance. All surfaces revealed slightly reduced susceptibility to pit initiation and metastable pitting as compared to wrought 316L, possibly explained by the absence of inclusions. Once pitting propagation was induced, repassivation was hindered for all surfaces compared with the wrought surface. The pitting corrosion resistance of the as-superfinished 316L was improved compared with wrought 316L.
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| 6. |
- Atapour, Masoud, et al.
(författare)
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Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions
- 2019
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Ingår i: Food Control. - : ELSEVIER SCI LTD. - 0956-7135 .- 1873-7129. ; 101, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 hat room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks.
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| 7. |
- Atapour, Masoud, et al.
(författare)
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Stainless steel in simulated milk and whey protein solutions - Influence of grade on corrosion and metal release
- 2020
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Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Reactions at the biointerfaces between stainless steel and protein-rich dairy products, which contain whey proteins, are important to consider in terms of food safety and material grade selection. Changes in corrosion behavior, metal release, and surface composition of austenitic (AISI 316 L), ferritic (AISI 430), and lean duplex (LDX 2101) stainless steels in simulated milk (SMS) and whey protein solution were investigated. The amount of released metals and the corrosion susceptibility increased according to 2101 < 316 L < 430. All grades revealed low corrosion rates in the whey protein solution without any sign of active/metastable corrosion. Pitting corrosion was evident for 430 in SMS. The total amount of released metals (iron, chromium, and nickel) was significantly higher in whey protein solution compared with SMS. This suggests the metal release process to be mainly governed by complexation reactions. Nickel was preferentially released compared to its bulk composition fraction for both 316 L and 2101 in the highly complexing SMS. Reduced metal release rates with time correlated with the enrichment of chromium in the surface oxide. The extent of metal release was for all metals substantially lower than release limits of metals stipulated in health regulations related to the use of alloys and metals in food-related environments.
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| 8. |
- Bahar, Babak, et al.
(författare)
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Corrosion-induced copper release from rain gutters
- 2008
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Ingår i: Metall (Berlin. 1947). - 0026-0746. ; 62:3, s. 129-135
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Tidskriftsartikel (refereegranskat)abstract
- While runoff rates from copper roofs have been extensively studied during the last years, corresponding studies from copper rain gutters have been missing. A laboratory investigation has been undertaken to examine the influence of important runoff water parameters on the copper runoff from rain gutters. At a given rainfall quantity, the release rate of copper increases with decreasing runoff water intensity and decreasing degree of gutter inclination, and with increasing runoff acidity and increasing Cu2+-ion concentration in the runoff water. A comparison of the predicted long-term copper release from the gutter-system compared to the roof on a real building suggests that less than 5% of the total copper runoff originates from the gutter. However, single rain events may result in higher release rates, especially during the initial rain portion.
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| 9. |
- Bahar, B., et al.
(författare)
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The interaction between concrete pavement and corrosion-induced copper runoff from buildings
- 2008
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Ingår i: Environmental Monitoring & Assessment. - : Springer Science and Business Media LLC. - 0167-6369 .- 1573-2959. ; 140:1-3, s. 175-189
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Tidskriftsartikel (refereegranskat)abstract
- Changes in chemical speciation of copper and the capacity of concrete pavement to retain copper in runoff water from external buildings have been investigated at urban field conditions, and in parallel laboratory experiments simulating outdoor scenarios. The research study showed the concrete surface to form a copper rich surface layer (approximate to 50 mu m thick) upon exposure, and a high capacity to significantly reduce the bioavailable fraction of released copper (20-95%). The retention capacity of copper varied between 5 and 20% during single runoff events in the laboratory, and between 10 and 40% of the total copper release during single natural runoff events. The capacity to retain and reduce the bioavailable fraction of non-retained copper increased with increasing wetness of the concrete surfaces, increasing pH of the runoff water and decreasing flow rates. Bioassay testing with bacterial and yeast bioreporters showed the bioavailable fraction of non-retained copper to be significantly lower than the total copper concentration in the runoff water, between 22 and 40% for bacteria and between 8 and 31% for yeast. The application of generated data to simulate a fictive outdoor scenario, suggests a significant reduction of bioavailable and total copper to background values during environmental entry as a result of dilution, and the interaction with solid surfaces, organic matter and complexing agents already in the drainage system.
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| 10. |
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| 11. |
- Bertling, Sofia, 1970-
(författare)
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Corrosion-included metal runoff from external constructions and its environmental interaction : a combined field and laboratory investigation of Zn, Cu, Cr and Ni for risk assessment
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The 1990s has seen an increased awareness of possible environmental effects of corrosion-induced metal release from outdoor constructions. Considerable efforts have been initiated to perform critical assessments of possible risks of selected metals. Gaps of knowledge have been identified and research investigations started. This doctoral thesis is the result of an interdisciplinary research effort in which scientific insight into corrosion, soil chemistry and ecotoxicology has been integrated. The work comprises atmospheric exposure of pure metals and commercial materials for outdoor use. The focus is on release of four metals, copper, zinc, chromium and nickel. Their chemical speciation and bioavailable fraction in metal runoff were determined, both at the release moment and after environmental interaction with, e.g., soil and limestone. Total metal concentrations in runoff are influenced both by material properties (e.g., corrosion product solubility, and specific surface area) and by exposure parameters (e.g., rain volume, intensity, contact time and pollutants). Long-term runoff rates of copper, zinc, chromium and nickel were based on exposures (4-8 years) at standardized conditions (45o inclination facing south) in Stockholm, Sweden. Runoff rates for pure copper range from 1.2 to 1.5 g m-2 yr-1, depending on year. At the copper release moment the potential environmental effect was evaluated using 72 hours growth inhibition test with the green algae Raphidocelis subcapitata. This resulted in a mean value of 15 μg L-1 causing a 50% growth reduction (EC50). Long-term runoff rates for pure zinc range from 1.9 to 2.5 g m-2 yr-1. A considerable variation in average annual runoff rates (0.07-2.5 mg zinc m2yr-1) was observed between different investigated commercial zinc-based materials. An average 72 hour (EC50) value of 69 μg L-1 towards Raphidocelis subcapitata was found for runoff water from zinc-based materials. Long-term runoff rates from stainless steel of grade 304 and 316 range from 0.23 to 0.30 chromium and 0.28 to 0.52 nickel mg m-2 yr-1, with corresponding concentrations in the runoff at the release moment far below reported ecotoxic concentrations for chromium and nickel. Two predictive runoff rate models were successfully developed for transforming copper runoff rate data from Stockholm to other exposure sites. One model is based on rain pH, yearly precipitation and building geometry, and the other on average annual SO2 concentration, yearly precipitation and building geometry. In addition to total metal concentration, adequate effect assessments also require information on chemical speciation of the released metal and its bioavailability. Metal chemical speciation in runoff was determined experimentally through an ion selective electrode (for copper), and also modelled with the Windermere Humic Aquatic model (WHAM (V)). Bioavailability assessments were generated through bioassay tests. At the moment of metal release, all methods show that the majority (60-99%) of the metal in runoff exists in its most bioavailable form, the hydrated metal ion. During subsequent environmental entry the metal undergoes major reductions in concentration and bioavailability. This was evidenced by model column studies of the capacity of soil to retain and immobilize the metal in runoff water, and by model and field column studies of the capacity of limestone to retain copper. The retention by soil of all metals investigated is very high (96-99.8%) until each materials retention capacity is reached. Limestone also exhibits a substantial capacity (5- 47%) to retain copper. The capacity is significantly increased by increased amount and decreased fraction of limestone particles. Any outer or inner surface with significant retention ability and with low possibility of subsequent mobilization is an excellent candidate for neutralizing metal release and its potential ecotoxic effects. This was demonstrated through computer modelling (WHAM(V)) and biosensor tests (Biomet™), which showed the most bioavailable and ecotoxic metal species to be reduced during passage through soil and limestone. Predictions based on the computer model HYDRUS-1D suggest a time-period of between 4 and 8000 years, depending on runoff water and soil characteristics, before saturation in soil retention capacity of copper and zinc is reached. A significant fraction of the retained metal is extractable towards the strong complexing agent EDTA, indicating possible future mobilisation. It is also available for plant uptake, as shown by DGT- (Diffuse Gradients in Thin films-) analysis of copper and zinc in soil. The data generated, presented and discussed are all believed to be important for risk assessment work related to corrosion-induced metal release from outdoor constructions. As evidenced from this doctoral thesis, such work requires a complete set of data on annual runoff rates, concentrations, chemical speciation and bioavailability and its changes during environmental entry, together with knowledge on, e.g., type of material, service life of coating, building geometry, and dewatering system.
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| 12. |
- Bertling, Sofia, et al.
(författare)
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Environmental effects of zinc runoff from roofing materials : a new multidisciplinary approach
- 2002
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Ingår i: Outdoor Atmospheric Corrosion. - 0803128967 ; , s. 200-215
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Konferensbidrag (refereegranskat)abstract
- The objective of this work is to study changes in concentration and bioavailability of zinc-containing runoff water, released from roofing materials, upon passage through soil. The experimental approach is based on simulating the interaction between zinc in artificial runoff water and soil in a column system. The total zinc concentration of runoff was substantially reduced when passing through the soil and suggests marked zinc retention, During a constant flow and supply of zinc into the soil, equivalent to three and a half years of precipitation in Stockholm, a zinc retention capacity of approximately 99% was recorded, Not only the total concentration, but also the bio-available portion of the total zinc concentration was reduced after passage through soil, Most of the retained zinc was located in top 3 cm of the soil core and suggests the total capacity for zinc retention of the investigated soil to be about 140 years per kilogram soil in an isolated system in real systems, changes of temperature, pH, microbial activity, weathering of minerals and deposition of new organic material must be considered. The results form part of the effect assessment, preceding future risk assessment of the environmental effects of dispersed zinc.
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| 13. |
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| 14. |
- Bertling, Sofia, et al.
(författare)
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Long-term corrosion-induced copper runoff from natural and artificial patina and its environmental impact
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 25:3, s. 891-898
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Tidskriftsartikel (refereegranskat)abstract
- The overall objective of this paper is to present an extensive set of data for corrosion-induced copper dispersion and its environmental interaction with solid surfaces in the near vicinity of buildings. Copper dispersion is discussed in terms of total copper flows, copper speciation and bioavailability at the immediate release situation, and its changes during transport from source to recipient. Presented results are based on extensive field exposures (eight years) at an urban site, laboratory investigations of the runoff process, published field data, generated predictive site-specific runoff rate models, and reactivity investigations toward various natural and manmade surfaces, such as those in soil, limestone, and concrete. Emphasis is placed on the interaction of copper-containing runoff water with different soil systems through long-term laboratory column investigations. The fate of copper is discussed in terms of copper retention, copper chemical speciation, breakthrough capacities, and future mobilization based on changes in copper concentrations in the percolate water, computer modeling using the Windermere Humic Aqueous Model, and sequential extractions. The results illustrate that, for scenarios where copper comes in extensive contact with solid surfaces, such as soil and limestone, a large fraction of released copper is retained already in the immediate vicinity of the building. In all, both the total copper concentration in runoff water and its bioavailable part undergo a significant and rapid reduction.
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| 15. |
- Bertling, Sofia, et al.
(författare)
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Model studies of corrosion induced copper runoff fate in soil
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 25:3, s. 683-691
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Tidskriftsartikel (refereegranskat)abstract
- Laboratory experiments have been performed with 3-cm soil columns simulating the fate of corrosion-induced copper runoff in contact with soil. The investigation simulates approximately 30 years (assuming an infiltration surplus of 25 cm/year) of continuous percolation of copper containing runoff water of a concentration realistic at the immediate release situation (4.8 mg/L) into four soils representative of urban conditions. Two of the three investigated topsoils reached their breakthrough of copper within the simulated time, while the third topsoil did not show a breakthrough. The subsoil reached a breakthrough after approximately 10 years of simulated exposure. To simulate more realistic outdoor scenarios, the laboratory-obtained breakthrough curves were modeled with Hydrus-1D (R) using a Langmuir-Freundlich model to describe copper sorption, the parameters of which were estimated from soil properties (pH, organic carbon content). The model predicts longer breakthrough times with increasing pH and organic content of the soil and with decreasing concentrations of copper and dissolved organic carbon in the runoff water. The time span for copper in runoff water (at concentrations of 0.01-10 mg/L) to reach a soil depth of 50 cm varied between 170 and more than 8,000 years for the predicted field scenarios.
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| 16. |
- Bertling, Sofia, et al.
(författare)
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Occurrence and fate of corrosion-induced zinc in runoff water from external structures
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 367:2-3, s. 908-923
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Tidskriftsartikel (refereegranskat)abstract
- This paper comprises data from an extensive cross-disciplinary research project aiming to elucidate the environmental fate of corrosion-induced zinc release from external structures. It includes an exposure assessment that provide long-term runoff rates, concentrations and chemical speciation of zinc, from 14 zinc-based materials exposed during 5 years in Stockholm, Sweden, and an effect assessment including bioavailability and ecotoxicity measurements, both at the immediate release situation and after soil interaction.Runoff rates of total zinc ranged from 0.07 to 2.5g Znm(-2) yr(-1) with zinc primarily released as the free ion for all materials investigated. The average effect concentration, causing a 50% growth reduction after 72h to the green algae Raphidocelis subcapitata, was at the immediate release situation 69 mu g ZnL-1. Upon interaction of runoff water with soil, which simulated 18 to 34years of exposure, the total zinc concentration was significantly reduced, from milligram per litre to microgram per litre levels. Simultaneously, the most bioavailable fraction of zinc in runoff, the hydrated zinc(II)-ion, decreased from more than 95% to about 30%. The major fraction, 98-99%, of the introduced total zinc concentration in the runoff water was retained within the soil. As long as the soil retention capacity was not reached, this resulted in zinc concentrations in the percolate water transported through the soil layer, close to background values and below growth inhibition concentrations for the green algae investigated. Zinc retained in soil was to a large extent (85-99.9%) extractable with EDTA, and available for plant uptake after 5 to 7months of ageing.
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| 17. |
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| 18. |
- Besharat, Zahra, et al.
(författare)
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Mixed monolayers of alkane thiols with polar terminal group on gold : Investigation of structure dependent surface properties
- 2016
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 484, s. 279-290
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption of thiols with cationic or anionic terminal group on gold has been studied from mixed solutions of 11-Amino-1-undecanethiol (AUT) and 3-Mercaptopropionic acid (MPA) using Quartz Crystal Microbalance with Dissipation (QCM-D), X-ray Photoelectron Spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The goal is to probe the nature of such layers, and the additivity or otherwise of the pH responsiveness, with a view to evaluate their suitability as smart materials. For each of the two pure (unmixed) cases, ordered molecular monolayers are formed with sulfur binding to gold and the alkane chain pointing out from the surface as expected. Adsorption from the thiol mixtures, however, leads to a more complex behaviour. The surface concentration of thiols from the mixtures, as determined by QCM-D, is considerably lower than for the pure cases and it reaches a minimum at a 3:1 MPA/AUT relative concentration in the solution. The XPS results confirm a reduction in adsorbed amount in mixtures with the lowest overall intensity for the 3:1 ratio. Monolayers formed from mixtures display a wettability which is much lower and less pH sensitive. Collectively these results confirm that for adsorption from mixed systems, the configuration is completely different. Complex formation in the mixed solutions leads to the adsorption of molecules parallel to the surface in an axially in-plane configuration. This parallel layer of thiols is mechanically relatively robust to nano-shaving based on AFM measurements. These results will have a significant impact on the design of biomimetic surface coatings particularly when mixtures of oppositely charged molecules are present on the surface, as is commonly the case in biological, proteinaceous surfaces (e.g. hair and skin).
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| 19. |
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| 20. |
- Cappellini, Francesca, et al.
(författare)
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Dry Generation of CeO2 Nanoparticles and Deposition onto a Co-Culture of A549 and THP-1 Cells in Air-Liquid Interface-Dosimetry Considerations and Comparison to Submerged Exposure
- 2020
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Relevant in vitro assays that can simulate exposure to nanoparticles (NPs) via inhalation are urgently needed. Presently, the most common method employed is to expose lung cells under submerged conditions, but the cellular responses to NPs under such conditions might differ from those observed at the more physiological air-liquid interface (ALI). The aim of this study was to investigate the cytotoxic and inflammatory potential of CeO2 NPs (NM-212) in a co-culture of A549 lung epithelial cells and differentiated THP-1 cells in both ALI and submerged conditions. Cellular dose was examined quantitatively using inductively coupled plasma mass spectrometry (ICP-MS). The role of serum and LPS-priming for IL-1 beta release was further tested in THP-1 cells in submerged exposure. An aerosol of CeO2 NPs was generated by using the PreciseInhale (R) system, and NPs were deposited on the co-culture using XposeALI (R). No or minor cytotoxicity and no increased release of inflammatory cytokines (IL-1 beta, IL-6, TNF alpha, MCP-1) were observed after exposure of the co-culture in ALI (max 5 mu g/cm(2)) or submerged (max 22 mu g/cm(2)) conditions. In contrast, CeO2 NPs cause clear IL-1 beta release in monocultures of macrophage-like THP-1, independent of the presence of serum and LPS-priming. This study demonstrates a useful approach for comparing effects at various in-vitro conditions.
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| 21. |
- Cappellini, Francesca, et al.
(författare)
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Mechanistic insight into reactivity and (geno)toxicity of well-characterized nanoparticles of cobalt metal and oxides
- 2018
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Ingår i: Nanotoxicology. - : Taylor & Francis. - 1743-5390 .- 1743-5404. ; 12:6, s. 602-620
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Tidskriftsartikel (refereegranskat)abstract
- An increasing use of cobalt (Co)-based nanoparticles (NPs) in different applications and exposures at occupational settings triggers the need for toxicity assessment. Improved understanding regarding the physiochemical characteristics of Co metal NPs and different oxides in combination with assessment of toxicity and mechanisms may facilitate decisions for grouping during risk assessment. The aim of this study was to gain mechanistic insights in the correlation between NP reactivity and toxicity of three different Co-based NPs (Co, CoO, and Co3O4) by using various tools for characterization, traditional toxicity assays, as well as six reporter cell lines (ToxTracker) for rapid detection of signaling pathways of relevance for carcinogenicity. The results showed cellular uptake of all NPs in lung cells and induction of DNA strand breaks and oxidative damage (comet assay) by Co and CoO NPs. In-depth studies on the ROS generation showed high reactivity of Co, lower for CoO, and no reactivity of Co3O4 NPs. The reactivity depended on the corrosion and transformation/dissolution properties of the particles and the media highlighting the role of the surface oxide and metal speciation as also confirmed by in silico modeling. By using ToxTracker, Co NPs were shown to be highly cytotoxic and induced reporters related to oxidative stress (Nrf2 signaling) and DNA strand breaks. Similar effects were observed for CoO NPs but at higher concentrations, whereas the Co3O4 NPs were inactive at all concentrations tested. In conclusion, our study suggests that Co and CoO NPs, but not Co3O4, may be grouped together for risk assessment.
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| 22. |
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| 23. |
- Chang, Tingru, et al.
(författare)
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A mechanistic study of stratified patina evolution on Sn-bronze in chloride-rich atmospheres
- 2020
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Ingår i: Corrosion Science. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0010-938X .- 1879-0496. ; 166
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Tidskriftsartikel (refereegranskat)abstract
- The complex stratified patina formed on Sn-bronze in chloride-rich atmospheres has been explored through long-term field exposures and short-term laboratory investigations using a multi-analytical approach. The stratified patina is composed of Cu2O- and Cu-2(OH)(3)Cl-rich sublayers intercalated by Sn-oxides, mainly SnO2. The stratification is triggered by events of high chloride deposition, resulting in repeated dissolution and solidification of sublayers, whereby redox reactions between the intermediate products of Sn- and Cu-chlorides play a crucial role. Sn-induced patina stratification is a major reason for enhanced patina flaking on Sn-bronze and its accelerated corrosion rate compared to Cu metal in marine environments.
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| 24. |
- Chang, Tingru, et al.
(författare)
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A novel methodology to study antimicrobial properties of high-touch surfaces used for indoor hygiene applications-A study on Cu metal
- 2021
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Metal-based high-touch surfaces used for indoor applications such as doorknobs, light switches, handles and desks need to remain their antimicrobial properties even when tarnished or degraded. A novel laboratory methodology of relevance for indoor atmospheric conditions and fingerprint contact has therefore been elaborated for combined studies of both tarnishing/corrosion and antimicrobial properties of such high-touch surfaces. Cu metal was used as a benchmark material. The protocol includes pre-tarnishing/corrosion of the high touch surface for different time periods in a climatic chamber at repeated dry/wet conditions and artificial sweat deposition followed by the introduction of bacteria onto the surfaces via artificial sweat droplets. This methodology provides a more realistic and reproducible approach compared with other reported procedures to determine the antimicrobial efficiency of high-touch surfaces. It provides further a possibility to link the antimicrobial characteristics to physical and chemical properties such as surface composition, chemical reactivity, tarnishing/corrosion, surface roughness and surface wettability. The results elucidate that bacteria interactions as well as differences in extent of tarnishing can alter the physical properties (e.g. surface wettability, surface roughness) as well as the extent of metal release. The results clearly elucidate the importance to consider changes in chemical and physical properties of indoor hygiene surfaces when assessing their antimicrobial properties.
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| 25. |
- Chang, Tingru, et al.
(författare)
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Analysis of historic copper patinas. Influence of inclusions on patina uniformity
- 2017
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- The morphology and elemental composition of cross sections of eight historic copper materials have been explored. The materials were taken from copper roofs installed in different middle and northern European environments from the 16th to the 19th century. All copper substrates contain inclusions of varying size, number and composition, reflecting different copper ores and production methods. The largest inclusions have a size of up to 40 μm, with most inclusions in the size ranging between 2 and 10 μm. The most common element in the inclusions is O, followed by Pb, Sb and As. Minor elements include Ni, Sn and Fe. All historic patinas exhibit quite fragmentized bilayer structures, with a thin inner layer of cuprite (Cu2O) and a thicker outer one consisting mainly of brochantite (Cu4SO4(OH)6). The extent of patina fragmentation seems to depend on the size of the inclusions, rather than on their number and elemental composition. The larger inclusions are electrochemically nobler than the surrounding copper matrix. This creates micro-galvanic effects resulting both in a profound influence on the homogeneity and morphology of historic copper patinas and in a significantly increased ratio of the thicknesses of the brochantite and cuprite layers. The results suggest that copper patinas formed during different centuries exhibit variations in uniformity and corrosion protection ability.
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