| 11. |
- Ferrara, R, et al.
(författare)
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Mercury Emissions Into the Atmosphere From A Chlor-alkali Complex Measured With the Lidar Technique
- 1992
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Ingår i: Atmospheric Environment Part A-general Topics. - 0004-6981. ; 26:7, s. 1253-1258
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Tidskriftsartikel (refereegranskat)abstract
- Data are reported on atmospheric mercury flux measured by a lidar system at a chlor-alkali plant located in central Italy. Two mercury sources were identified over the electrolytic cell rooms. A flux value of 36 g h-1 was determined during the daytime while at night the value increase to 56 g h-1. The mercury emitted into the atmosphere was found to be 4 g per 1000 kg of chlorine produced. Atmospheric mercury concentrations were supplemented with some determinations made with the point monitor technique.
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| 12. |
- Ferrara, R, et al.
(författare)
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Vertical Profiles of Atmospheric Mercury Concentration
- 1992
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Ingår i: Environmental Technology. - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 13:11, s. 1061-1068
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Tidskriftsartikel (refereegranskat)abstract
- Vertical profiles of atmospheric mercury concentration determined with a lidar and point monitor systems in the mineralized region of Mt. Amiata (Italy) are reported. Measurements were performed over a large flat area, without arboreal and herbaceous vegetation, constituting a roasted cinnabar deposit which still contains about two parts per thousand of mercury. The determinations carried out with the two techniques yielded comparable results for the working conditions used. Data demonstrate the presence of a vertical gradient of atmospheric mercury concentration, which is particularly large in the layers of air nearest the soil. The highest values (45-1000 ng m-3) were measured a few centimeters from the soil, while background values (2-3 ng m-3) were reached at heights of 10-20 m. The vertical gradient proved to be strongly dependent on ambient temperature.
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| 13. |
- Forsberg, Johan, et al.
(författare)
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System for in situ studies of atmospheric corrosion of metal films using soft x-ray spectroscopy and quartz crystal microbalance
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:8
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Tidskriftsartikel (refereegranskat)abstract
- We present a versatile chamber (atmospheric corrosion cell) for soft x-ray absorption/emission spectroscopy of metal surfaces in a corrosive atmosphere allowing novel in situ electronic structure studies. Synchrotron x rays passing through a thin window separating the corrosion cell interior from a beamline vacuum chamber probe a metal film deposited on a quartz crystal microbalance (QCM) or on the inside of the window. We present some initial results on chloride induced corrosion of iron surfaces in humidified synthetic air. By simultaneous recording of QCM signal and soft x-ray emission from the corroding sample, correlation between mass changes and variations in spectral features is facilitated.
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| 14. |
- Hedberg, Yolanda S., et al.
(författare)
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Electrochemical surface oxide characteristics of metal nanoparticles (Mn, Cu and Al) and the relation to toxicity
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 212, s. 360-371
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Tidskriftsartikel (refereegranskat)abstract
- Most metal nanoparticles (NPs), except noble metal NPs, rapidly form a thin surface oxide in ambient conditions. The protective properties of these oxides improve or worsen depending on the environment, e.g., the human lung. Several properties, including the chemical/electrochemical stability and defect density, determine the capacity of these surface oxides to hinder the bulk metal from further oxidation (corrosion). The aim of this study was to investigate whether electrochemical surface oxide characterization of non-functionalized base metal NPs of different characteristics (Al, Mn and Cu) can assist in understanding their bioaccessibility (metal release) in cell media (DMEM+) and their cytotoxic properties following exposure in lung epithelial (A549) cells. The composition and valence states of surface oxides of metal NPs and their electrochemical activity were investigated using an electrochemical technique based on a graphite paste electrode to perform cyclic voltammetry in buffer solutions and open circuit potential measurements in DMEM+. The electrochemical surface oxide characterization was complemented and verified by Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The open circuit potential trends in DMEM+ correlated well with metal release results in the same solution, and provided information on the kinetics of oxide dissolution in the case of Cu NPs. Extensive particle agglomeration in cell medium (DMEM+) was observed by means of photon-cross correlation spectroscopy for all metal NPs, with sedimentation taking place very quickly. As a consequence, measurements of the real dose of added non-functionalized metal NPs to cell cultures for cytotoxicity testing from a sonicated stock solution were shown necessary. The cytotoxic response was found to be strongly correlated to changes in physico-chemical and electrochemical properties of the surface oxides of the metal NPs, the most potent being Cu NPs, followed by Mn NPs. No cytotoxicity was observed for Al NPs. The electrochemical surface oxide characterization corresponded well with other tools commonly used for nanotoxicological characterization and provided additional information.
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| 15. |
- Hedberg, Yolanda, Docent, 1985-, et al.
(författare)
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Welding fume nanoparticles from solid and flux-cored wires : Solubility, toxicity, and role of fluorides
- 2021
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 413
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Tidskriftsartikel (refereegranskat)abstract
- Welding fume particles are hazardous. Their toxicity likely depends on their composition and reactivity. This study aimed at exploring the role of sodium or other fluorides (NaF), which are intentionally added to flux-cored wire electrodes for stainless steel welding, on the solubility (in phosphate buffered saline) and toxicity of the generated welding fume particles. A multi-analytical particle characterization approach along with in-vitro cell assays was undertaken. The release of Cr(VI) and Mn from the particles was tested as a function of fluoride solution concentration. The welding fume particles containing NaF released significantly higher amounts of Cr (VI) compared with solid wire reference fumes, which was associated with increased cytotoxicity and genotoxicity in-vitro. No crystalline Na or potassium (K) containing chromates were observed. Cr(VI) was incorporated in an amorphous mixed oxide. Solution-added fluorides did not increase the solubility of Cr(VI), but contributed to a reduced Mn release from both solid and flux-cored wire fume particles and the reduction of Cr (VI) release from solid wire fume particles. Chemical speciation modeling suggested that metal fluoride complexes were not formed. The presence of NaF in the welding electrodes did not have any direct, but possibly an indirect, role in the Cr(VI) solubility of welding fumes.
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| 16. |
- Henderson, Rayetta G., et al.
(författare)
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Inter-laboratory validation of bioaccessibility testing for metals
- 2014
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Ingår i: Regulatory toxicology and pharmacology. - : Elsevier BV. - 0273-2300 .- 1096-0295. ; 70:1, s. 170-181
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Tidskriftsartikel (refereegranskat)abstract
- Bioelution assays are fast, simple alternatives to in vivo testing. In this study, the intra- and inter-laboratory variability in bioaccessibility data generated by bioelution tests were evaluated in synthetic fluids relevant to oral, inhalation, and dermal exposure. Using one defined protocol, five laboratories measured metal release from cobalt oxide, cobalt powder, copper concentrate, Inconel alloy, leaded brass alloy, and nickel sulfate hexahydrate. Standard deviations of repeatability (S-r) and reproducibility (S-R) were used to evaluate the intra- and inter-laboratory variability, respectively. Examination of the s(R):s(r) ratios demonstrated that, while gastric and lysosomal fluids had reasonably good reproducibility, other fluids did not show as good concordance between laboratories. Relative standard deviation (RSD) analysis showed more favorable reproducibility outcomes for some data sets; overall results varied more between- than within-laboratories. RSD analysis of s(r) showed good within-laboratory variability for all conditions except some metals in interstitial fluid. In general, these findings indicate that absolute bioaccessibility results in some biological fluids may vary between different laboratories. However, for most applications, measures of relative bioaccessibility are needed, diminishing the requirement for high inter-laboratory reproducibility in absolute metal releases. The inter-laboratory exercise suggests that the degrees of freedom within the protocol need to be addressed.
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| 17. |
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| 18. |
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| 19. |
- Jarfors, Anders, 1963-, et al.
(författare)
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Reactions during infiltration of graphite fibres by molten Al-Ti alloy
- 1993
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Ingår i: Metallurgical and Materials Transactions. A. - 1073-5623 .- 1543-1940. ; 24:11, s. 2577-2583
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Tidskriftsartikel (refereegranskat)abstract
- The infiltration sequence of graphite fibers with liquid aluminum alloyed with titanium was studied. The titanium concentration was chosen such that a severe reaction occurred between the fibers and the melt. Aluminum carbide and titanium carbide, as well as an aluminide phase were formed. The phenomenon occurring during the infiltration sequence was explained with the aid of the ternary-phase diagram Al-Ti-C. The effect of the reaction on the infiltration height is discussed.
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| 20. |
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