| 1. |
- Viklund, Peter, et al.
(författare)
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Effect of sulphur containing additive on initial corrosion of superheater tubes in waste fired boiler
- 2009
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Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 44:3, s. 234-240
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Tidskriftsartikel (refereegranskat)abstract
- The major drawback to generating electricity from waste fired boilers is the rapid corrosion of superheaters which increases the maintenance costs. Within the last few years, it has been shown that additions of ammonium sulphate to biomass fired boilers decrease the corrosion tendencies. This paper reports on the effects of ammonium sulphate on corrosion in a waste fired CFB boiler. Air cooled probes were exposed at a position corresponding to the one of superheater tubes. The probe temperature was 500 degrees C, corresponding to a steam temperature of similar to 450 degrees C. Both the austenitic steel EN1.4301 (Fe-18Cr-9Ni) and the low alloyed ferritic steel EN1.7380 (Fe-2.25Cr-1Mo) were tested. During exposure, the concentration of alkali chlorides in the flue gas was measured and a decrease was observed when adding ammonium sulphate. After 4 h of exposure, the probes were removed for detailed analysis with SEM-EDS, TOF-SIMS and XRD. The sides of the tubes facing the flue gas were covered with a calcium rich deposit, while relatively more sodium and potassium were present on the lee side. The results also show that ammonium sulphate shifted the deposit composition from chloride rich and highly corrosive, to one significantly less corrosive and dominated by sulphates of sodium, potassium and calcium. Metallography shows a marked difference in corrosion attack between the two steels. Iron chlorides accumulate at the metal/oxide interface of the ferritic steel, while the amounts of iron chlorides were significantly lower in the austenitic steel. These results indicate that ammonium sulphate has the potential to reduce corrosion in waste fired boilers and that austenitic stainless steels are more likely to resist corrosion in these environments than low alloyed ferritic steels.
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| 2. |
- Hammarstedt, Maria, et al.
(författare)
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Purification of infectious human herpesvirus 6A virions and association of host cell proteins
- 2007
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Ingår i: Virology Journal. - 1743-422X. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Viruses that are incorporating host cell proteins might trigger autoimmune diseases. It is therefore of interest to identify possible host proteins associated with viruses, especially for enveloped viruses that have been suggested to play a role in autoimmune diseases, like human herpesvirus 6A (HHV-6A) in multiple sclerosis (MS). RESULTS: We have established a method for rapid and morphology preserving purification of HHV-6A virions, which in combination with parallel analyses with background control material released from mock-infected cells facilitates qualitative and quantitative investigations of the protein content of HHV-6A virions. In our iodixanol gradient purified preparation, we detected high levels of viral DNA by real-time PCR and viral proteins by metabolic labelling, silver staining and western blots. In contrast, the background level of cellular contamination was low in the purified samples as demonstrated by the silver staining and metabolic labelling analyses. Western blot analyses showed that the cellular complement protein CD46, the receptor for HHV-6A, is associated with the purified and infectious virions. Also, the cellular proteins clathrin, ezrin and Tsg101 are associated with intact HHV-6A virions. CONCLUSION: Cellular proteins are associated with HHV-6A virions. The relevance of the association in disease and especially in autoimmunity will be further investigated.
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| 3. |
- Ryner, Martin, et al.
(författare)
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Identification and classification of human cytomegalovirus capsids in textured electron micrographs using deformed template matching
- 2006
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Ingår i: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Characterization of the structural morphology of virus particles in electron micrographs is a complex task, but desirable in connection with investigation of the maturation process and detection of changes in viral particle morphology in response to the effect of a mutation or antiviral drugs being applied. Therefore, we have here developed a procedure for describing and classifying virus particle forms in electron micrographs, based on determination of the invariant characteristics of the projection of a given virus structure. The template for the virus particle is created on the basis of information obtained from a small training set of electron micrographs and is then employed to classify and quantify similar structures of interest in an unlimited number of electron micrographs by a process of correlation. Results: Practical application of the method is demonstrated by the ability to locate three diverse classes of virus particles in transmission electron micrographs of fibroblasts infected with human cytomegalovirus. These results show that fast screening of the total number of viral structures at different stages of maturation in a large set of electron micrographs, a task that is otherwise both time-consuming and tedious for the expert, can be accomplished rapidly and reliably with our automated procedure. Using linear deformation analysis, this novel algorithm described here can handle capsid variations such as ellipticity and furthermore allows evaluation of properties such as the size and orientation of a virus particle. Conclusion: Our methodological procedure represents a promising objective tool for comparative studies of the intracellular assembly processes of virus particles using electron microscopy in combination with our digitized image analysis tool. An automated method for sorting and classifying virus particles at different stages of maturation will enable us to quantify virus production in all stages of the virus maturation process, not only count the number of infectious particles released from un infected cell.
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| 4. |
- Bálint, Adám, et al.
(författare)
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The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant
- 2009
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Ingår i: Virology Journal. - 1743-422X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The European swine influenza viruses (SIVs) show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority of the European H1N2 swine influenza viruses described so far possess haemagglutinin (HA) of the human-like H1N2 SIV viruses and the neuraminidase (NA) of either the European H1N2 or H3N2 SIV-like viruses. The Swedish isolate has an avian-like SIV HA and a H3N2 SIV-like NA, which is phylogenetically more closely related to H3N2 SIV NAs from isolates collected in the early '80s than to the NA of H3N2 origin of the H1N2 viruses isolated during the last decade, as depicted by some German strains, indicative of independent acquisition of the NA genes for these two types of reassortants. The internal genes proved to be entirely of avian-like SIV H1N1 origin. The prevalence of this SIV variant in pig populations needs to be determined, as well as the suitability of the routinely used laboratory reagents to analyze this strain.The description of this H1N2 SIV adds further information to influenza epidemiology and supports the necessity of surveillance for influenza viruses in pigs.
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| 5. |
- Christenson, Brith, et al.
(författare)
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Effect of influenza and pneumococcal vaccines in elderly persons in years of low influenza activity
- 2008
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Ingår i: Virology Journal. - 1743-422X. ; 5, s. 52-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The present prospective study was conducted from 2003-2005, among all individuals 65 years and older in Uppsala County, a region with 300 000 inhabitants situated close to the Stockholm urban area.The objective of this study was to assess the preventive effect of influenza and pneumococcal vaccination in reducing hospitalisation and length of hospital stay (LOHS) even during periods of low influenza activity. The specificity of the apparent vaccine associations were evaluated in relation to the influenza seasons. RESULTS: In 2003, the total study population was 41,059, of which 12,907 (31%) received influenza vaccine of these, 4,447 (11%) were administered the pneumococcal vaccine. In 2004, 14,799 (34%) individuals received the influenza vaccine and 8,843 (21%) the pneumococcal vaccine and in 2005 16,926 (39%) individuals were given the influenza vaccine and 12,340 (28%) the pneumococcal vaccine.Our findings indicated that 35% of the vaccinated cohort belonged to a medical risk category (mainly those persons that received the pneumococcal vaccine). Data on hospitalisation and mortality during the 3-year period were obtained from the administrative database of the Uppsala county council.During the influenza seasons, reduction of hospital admissions and significantly shorter in-hospital stay for influenza was observed in the vaccinated cohort (below 80 years of age). For individuals who also had received the pneumococcal vaccine, a significant reduction of hospital admissions and of in-hospital stay was observed for invasive pneumococcal disease and for pneumococcal pneumonia. Effectiveness was observed for cardiac failure even in persons that also had received the pneumococcal vaccine, despite that the pneumococcal vaccinated mainly belonged to a medical risk category. Reduction of death from all causes was observed during the influenza season of 2004, in the 75-84-year old age group and in all age-groups during the influenza season 2005. CONCLUSION: The present study confirmed the additive effect of the two vaccines in the elderly, which was associated with a reduced risk in hospitalisation and a reduction in mean LOHS in seasons with low influenza activity.
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| 6. |
- Hellström, Ulla B., et al.
(författare)
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PreS1 epitope recognition in newborns after vaccination with the third-generation Sci-B-Vac (TM) vaccine and their relation to the antibody response to hepatitis B surface antigen
- 2009
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Ingår i: Virology Journal. - 1743-422X. ; 6, s. 7-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sci-B-Vac T is a recombinant, hepatitis B vaccine derived from a mammalian cell line and containing hepatitis B surface antigen (HBsAg) as well as preS1 and preS2 antigens. Few studies have been performed on the antibody responses to preS1 in relation to the antibody to hepatitis B surface antigen (anti-HBs) response during immunisation of healthy children with preS-containing vaccines. Results: In this study 28 healthy newborns were randomly selected to receive either 2.5 ug or 5.0 ug of the Sci-B-Vac vaccine. Children received three doses of vaccine according to a 0-, 1-, 6- month scheme. Antibodies against the S-protein and three synthetic peptides mimicking three B-cell preS1 epitopes, (21-32 amino acid epitope), (32-47 amino acid epitope) and the C-terminal (amino acid epitope 94-117) were determined at 6 and 9 months. Fourteen (50%) of the 28 newborns had detectable levels of anti-preS1 (21-32) antibodies; 15 ( 54%) were anti-preS1 (32-47) reactive and 12 (43%) were anti-preS1 (94-117) reactive at 6 or 9 months after initiation of the vaccination. Significantly higher levels of anti-HBs were observed in the sera of patients with detectable anti-preS1 (32-47) reactivity (24 550 +/- 7375 IU/L, mean +/- SEM) as compared with the non-reactive sera (5991 +/- 1530 IU/L, p < 0.05). The anti-HBs levels were significantly lower if none (p < 0.05) or one (p < 0.025) of the preS1 (21-32, 32-47, 94-117) peptides were recognised compared with the anti-HBs levels if two or three peptides were recognised. Conclusion: Recognition of several preS1 epitopes, and in particular, the epitope contained within the second half of the hepatocyte binding site localised in the hepatitis B surface protein of the third-generation hepatitis B vaccine is accompanied by a more pronounced antibody response to the S-gene-derived protein in healthy newborns.
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| 7. |
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| 8. |
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| 9. |
- Jonsson, Nina, et al.
(författare)
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A rapid and efficient method for studies of virus interaction at the host cell surface using enteroviruses and real-time PCR
- 2009
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Ingår i: Virology Journal. - 1743-422X. ; 6:Article ID: 217
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Tidskriftsartikel (refereegranskat)abstract
- Background: Measuring virus attachment to host cells is of great importance when trying to identify novel receptors. The presence of a usable receptor is a major determinant of viral host range and cell tropism. Furthermore, identification of appropriate receptors is central for the understanding of viral pathogenesis and gives possibilities to develop antiviral drugs. Attachment is presently measured using radiolabeled and subsequently gradient purified viruses. Traditional methods are expensive and time-consuming and not all viruses are stable during a purification procedure; hence there is room for improvement. Real-time PCR (RT-PCR) has become the standard method to detect and quantify virus infections, including enteroviruses, in clinical samples. For instance, primers directed to the highly conserved 5' untranslated region (5'UTR) of the enterovirus genome enable detection of a wide spectrum of enteroviruses. Here, we evaluate the capacity of the RT-PCR technology to study enterovirus host cell interactions at the cell surface and compare this novel implementation with an established assay using radiolabeled viruses. Results: Both purified and crude viral extracts of CVB5 generated comparable results in attachment studies when analyzed with RT-PCR. In addition, receptor binding studies regarding viruses with coxsackie- nd adenovirus receptor (CAR) and/or decay accelerating factor (DAF) affinity, further demonstrated the possibility to use RT-PCR to measure virus attachment to host cells. Furthermore, the RT-PCR technology and crude viral extracts was used to study attachment with low multiplicity of infection (0.05 x 10(-4)TCID(50)/cell) and low cell numbers (250), which implies the range of potential implementations of the presented technique. Conclusion: We have implemented the well-established RT-PCR technique to measure viral attachment to host cells with high accuracy and reproducibility, at low cost and with less effort than traditional methods. Furthermore, replacing traditional methods with RT-PCR offers the opportunity to use crude virus containing extracts to investigate attachment, which could be considered as a step towards viral attachment studies in a more natural state.
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| 10. |
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| 11. |
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| 12. |
- Lagerqvist, Nina, 1979-, et al.
(författare)
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Characterisation of immune responses and protective efficacy in mice after immunisation with Rift Valley Fever virus cDNA constructs
- 2009
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Ingår i: Virology Journal. - 1743-422X. ; 6, s. 6-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Affecting both livestock and humans, Rift Valley Fever is considered as one of the most important viral zoonoses in Africa. However, no licensed vaccines or effective treatments are yet available for human use. Naked DNA vaccines are an interesting approach since the virus is highly infectious and existing attenuated Rift Valley Fever virus vaccine strains display adverse effects in animal trials. In this study, gene-gun immunisations with cDNA encoding structural proteins of the Rift Valley Fever virus were evaluated in mice. The induced immune responses were analysed for the ability to protect mice against virus challenge. RESULTS: Immunisation with cDNA encoding the nucleocapsid protein induced strong humoral and lymphocyte proliferative immune responses, and virus neutralising antibodies were acquired after vaccination with cDNA encoding the glycoproteins. Even though complete protection was not achieved by genetic immunisation, four out of eight, and five out of eight mice vaccinated with cDNA encoding the nucleocapsid protein or the glycoproteins, respectively, displayed no clinical signs of infection after challenge. In contrast, all fourteen control animals displayed clinical manifestations of Rift Valley Fever after challenge. CONCLUSION: The appearance of Rift Valley Fever associated clinical signs were significantly decreased among the DNA vaccinated mice and further adjustment of this strategy may result in full protection against Rift Valley Fever.
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| 13. |
- Mistry, Nitesh, et al.
(författare)
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Cutaneous and mucosal human papillomaviruses differ in net surface charge, potential impact on tropism.
- 2008
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Ingår i: Virology Journal. - 1743-422X. ; 5, s. 118-
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Tidskriftsartikel (refereegranskat)abstract
- Papillomaviruses can roughly be divided into two tropism groups, those infecting the skin, including the genus beta PVs, and those infecting the mucosa, predominantly genus alpha PVs. The L1 capsid protein determines the phylogenetic separation between beta types and alpha types and the L1 protein is most probably responsible for the first interaction with the cell surface. Virus entry is a known determinant for tissue tropism and to study if interactions of the viral capsid with the cell surface could affect HPV tropism, the net surface charge of the HPV L1 capsid proteins was analyzed and HPV-16 (alpha) and HPV-5 (beta) with a mucosal and cutaneous tropism respectively were used to study heparin inhibition of uptake. The negatively charged L1 proteins were all found among HPVs with cutaneous tropism from the beta- and gamma-PV genus, while all alpha HPVs were positively charged at pH 7.4. The linear sequence of the HPV-5 L1 capsid protein had a predicted isoelectric point (pI) of 6.59 and a charge of -2.74 at pH 7.4, while HPV-16 had a pI of 7.95 with a charge of +2.98, suggesting no interaction between HPV-5 and the highly negative charged heparin. Furthermore, 3D-modelling indicated that HPV-5 L1 exposed more negatively charged amino acids than HPV-16. Uptake of HPV-5 (beta) and HPV-16 (alpha) was studied in vitro by using a pseudovirus (PsV) assay. Uptake of HPV-5 PsV was not inhibited by heparin in C33A cells and only minor inhibition was detected in HaCaT cells. HPV-16 PsV uptake was significantly more inhibited by heparin in both cells and completely blocked in C33A cells.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Zohari, Siamak, et al.
(författare)
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Phylogenetic analysis of the non-structural (NS) gene of influenza A viruses isolated from mallards in Northern Europe in 2005
- 2008
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Ingår i: Virology Journal. - 1743-422X. ; 5:Article ID: 147
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although the important role of the non-structural 1 (NS) gene of influenza A in virulence of the virus is well established, our knowledge about the extent of variation in the NS gene pool of influenza A viruses in their natural reservoirs in Europe is incomplete. In this study we determined the subtypes and prevalence of influenza A viruses present in mallards in Northern Europe and further analysed the NS gene of these isolates in order to obtain a more detailed knowledge about the genetic variation of NS gene of influenza A virus in their natural hosts. Results: A total number of 45 influenza A viruses of different subtypes were studied. Eleven haemagglutinin-and nine neuraminidase subtypes in twelve combinations were found among the isolated viruses. Each NS gene reported here consisted of 890 nucleotides; there were no deletions or insertions. Phylogenetic analysis clearly shows that two distinct gene pools, corresponding to both NS allele A and B, were present at the same time in the same geographic location in the mallard populations in Northern Europe. A comparison of nucleotide sequences of isolated viruses revealed a substantial number of silent mutations, which results in high degree of homology in amino acid sequences. The degree of variation within the alleles is very low. In our study allele A viruses displays a maximum of 5% amino acid divergence while allele B viruses display only 2% amino acid divergence. All the viruses isolated from mallards in Northern Europe possessed the typical avian ESEV amino acid sequence at the C-terminal end of the NSI protein. Conclusion: Our finding indicates the existence of a large reservoir of different influenza A viruses in mallards population in Northern Europe. Although our phylogenetic analysis clearly shows that two distinct gene pools, corresponding to both NS allele A and B, were present in the mallards populations in Northern Europe, allele B viruses appear to be less common in natural host species than allele A, comprising only about 13% of the isolates sequenced in this study.
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| 19. |
- Goidanich, Sara, et al.
(författare)
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Corrosion induced metal release from copper based alloys compared to their pure elements
- 2008
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Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 43:2, s. 134-141
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Tidskriftsartikel (refereegranskat)abstract
- Despite numerous studies on atmospheric corrosion of copper and copper based alloys, the corrosion induced release processes of individual alloy constituents suffer from significant knowledge gaps. This investigation comprises metal release rate measurements of copper, zinc and tin from some copper based alloys including brass (20 wt-% Zn) and bronze (6 wt-% Sn), and their pure alloying metals, copper, zinc and tin. Data have been generated during a 2.5 year urban field exposure in Stockholm, Sweden and parallel laboratory investigations in a specially designed rain chamber using artificial rain. Brass shows significantly lower annual release rates of both copper and zinc compared to pure metal sheets of its alloy constituents. Zinc is preferentially released compared to copper. Dezincification of brass occurs both at field and laboratory conditions, a process influenced by rain characteristics. Alloying with tin does not largely reduce the release rate of copper from bronze compared to pure copper. No measurable amount of tin is released from the bronze surface.
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| 20. |
- Pettersson, Rachel, et al.
(författare)
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Materials performance in simulated waste combustion environments
- 2008
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Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 43:2, s. 123-128
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Tidskriftsartikel (refereegranskat)abstract
- Combustion of waste for power generation gives increased fouling and corrosion compared to fossil fuels, and leads to higher operating and maintenance costs. New materials solutions to increase lifetime include austenitic stainless steels, nickel base alloys, coatings and weld overlaying. In this work a simulated waste incineration environment with regularly renewed deposits of KCl - ZnCl(2) has been used to evaluate the performance of candidate materials and to elucidate the operative degradation mechanisms.
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| 21. |
- Prosek, Tomas, et al.
(författare)
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Real time corrosion monitoring in atmosphere using automated battery driven corrosion loggers
- 2008
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Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 43:2, s. 129-133
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Tidskriftsartikel (refereegranskat)abstract
- A logger enabling continuous measurement of corrosion rate of selected metals in indoor and outdoor atmospheres has been developed. Principle of the measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross-sectional area diminishes due to corrosion. Zinc, iron, copper and nickel sensors at several thicknesses are available. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be thus detected within hours or even tens of minutes. The logger lifetime in medium corrosive environments is designed to be 2 years with full autonomy. Data on the sensor corrosion rate are available any time through GPRS connection or by a non-contact inductive reading without the need of retracting the logger from the exposure site.
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