| 1. |
- Hellberg, P., et al.
(författare)
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A mathematical model of a blast furnace injection tuyere
- 2005
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 76:11, s. 755-763
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Tidskriftsartikel (refereegranskat)abstract
- One way to further utilise produced gases in an integrated metallurgical plant is to replace oil with gas as a reducing agent in a modern blast furnace. Accordingly, it is of great interest to study the injection of reducing gas into the blast furnace. Therefore, a three-dimensional mathematical model has been developed which simulates the injection of the gas by lances into the tuyere. The model includes the coupled solution of the flow field and the chemical reaction of the gases in the tuyere. Two different types of fuel gas, coke oven gas (COG) and basic oxygen furnace gas (BOF) have been modelled using one injection lance. The modelling technique is presented and discussed as well as the implied results. Furthermore, process parameters such as different gas compositions etc. are investigated using the developed model. Not surprisingly, the main results show that the COG is combusted more completely than BOF gas, which leads to higher flame temperature of the blast putting demand forward to lower the heat load of the tuyere. However, the modelling of the raceway is as far not included in the model, hence the influence of the outlet boundary condition at the tuyere is not reflected in the presented results.
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| 2. |
- Ballesteros, I., et al.
(författare)
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Lack of specificity of the molecular diagnosis method for identification of Aphanomyces astaci
- 2007
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Ingår i: BFPP-CONNAISSANCE ET GESTION DU PATRIMOINE AQUATIQUE. - : EDP Sciences. - 1297-6318. ; :385, s. 17-24
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Tidskriftsartikel (refereegranskat)abstract
- A recent PCR-test developed for identification of Aphanomyces astaci, the organism responsible for crayfish plague, provided false positives for Aphanomyces frigidophilus, Aphanomyces repetans, and some Saprolegnia spp. Real-time PCR showed that with the designed primers, A. astaci and A. frigidophilus cannot be distinguished. The results of this study show that this particular crayfish plague PCR-test ought to be improved and that molecular-based techniques need to be contrasted to histological evidences and disease history.
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| 3. |
- Bishop, Kevin, et al.
(författare)
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The Effects of Forestry on Hg Bioaccumulation in Nemoral/Boreal Waters and Recommendations for Good Silvicultural Practice
- 2009
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Ingår i: Ambio. - : Royal Swedish Academy of Sciences. - 0044-7447 .- 1654-7209. ; 38:7, s. 373-380
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Tidskriftsartikel (refereegranskat)abstract
- Mercury (Hg) levels are alarmingly high in fish from lakes across Fennoscandia and northern North America. The few published studies on the ways in which silviculture practices influence this problem indicate that forest operations increase Hg in downstream aquatic ecosystems. From these studies, we estimate that between one-tenth and one-quarter of the Hg in the fish of high-latitude, managed forest landscapes can be attributed to harvesting. Forestry, however, did not create the elevated Hg levels in the soils, and waterborne Hg/MeHg concentrations downstream from harvested areas are similar to those from wetlands. Given the current understanding of the way in which silviculture impacts Hg cycling, most of the recommendations for good forest practice in Sweden appear to be appropriate for high-latitude regions, e.g., leaving riparian buffer zones, as well as reducing disturbance at stream crossings and in moist areas. The recommendation to restore wetlands and reduce drainage, however, will likely increase Hg/MeHg loadings to aquatic ecosystems
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| 4. |
- Dieguez-Uribeondo, Javier, et al.
(författare)
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Pathogens, parasites and ectocommensals.
- 2006
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Ingår i: Atlas of crayfish in Europe. - : Publications Scientifiques du Muséum National d'Histoire Naturelle Vol. 64 “Patrimoines Naturels”. - 9782856535790 - 2856535798 ; , s. 135-155
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Bokkapitel (populärvet., debatt m.m.)
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| 5. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes)
- 2009
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 46:5, s. 365-376
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Tidskriftsartikel (refereegranskat)abstract
- Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.
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| 6. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Re-evaluation of the enigmatic species complex Saprolegnia diclina-Saprolegnia parasitica based on morphological, physiological and molecular data
- 2007
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 44:7, s. 585-601
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships among isolates of the Saprolegnia diclina-Saprolegnia parasitica complex were investigated based on ITS rDNA sequences, and correlated with morphological and physiological characters. The isolates studied belong to five phylogenetically separate clades. The majority of presumed parasitic isolates, mostly isolated from fish lesions, fell within a clade that comprises isolates which has been variously named as S. diclina Type 1, S. parasitica, Saprolegnia salmonis or just as unnamed Saprolegnia sp. Presence of bundles of long-hooked hairs on secondary cysts, high frequency of retracted germination, and oogonia production at 7 degrees C (when occurring) were characteristic of this clade. A single isolate identified as S. diclina Type 2 clustered in a clade along with Saprolegnia ferax isolates. The isolates identified as S. diclina s. str. (S. diclina Type 3) distributed in two clades and appeared closely related to Saprolegnia multispora and to a number of Chilean isolates identified as Saprolegnia australis. The ITS sequences of clade I were almost identical even though the isolates were of diverse geographical origins and showed physiological and morphological differences and variations in their pathogenicity. This suggest these species reproduces clonally even in apparently sexually competent isolates. Adaptation to parasitism in Saprolegnia might have occurred at spore level by the development of long-hooked hairs to facilitate host attachment and selection of a retracting germination. The use of the name S. parasitica should be assigned to isolates of clade I that contained isolates forming cysts with bundles of long-hooked hairs.
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| 7. |
- Hallberg, M., et al.
(författare)
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Process model of inclusion separation in a stirred steel ladle
- 2005
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Ingår i: Scandinavian journal of metallurgy. - : Wiley. - 0371-0459 .- 1600-0692. ; 34:1, s. 41-56
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model, which can be used as a process model in production, was developed to predict total oxygen content and size distribution of non-metallic inclusions in an agitated steel melt. Using a given pre-deoxidation total-oxygen-content value and calculated velocity and turbulence data (induction or gas stirring), model output can be generated as a function of stirring time. Predicted initial inclusion size distributions were in good agreement with inclusion size distributions quantitatively determined by light optical microscopy and classification according to the Swedish standard SS 11 11 16. Results from simulations carried out for the two types of stirring indicated that the model can predict total oxygen content and inclusion size distribution as a function of time for induction and gas stirring in an acceptable way.
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| 8. |
- Hallberg, Malin, et al.
(författare)
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Sulphur and hydrogen refining during vacuum degassing : a new concept for process control
- 2005
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Ingår i: Stahl und Eisen (1881). - 0340-4803. ; 125:5, s. 39-48
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to discuss how a fundamental mathematical model for prediction of hydrogen and sulphur refining during vacuum degassing can be used to develop on-line process control models. It has first been shown how predictions of sulphur and hydrogen using fundamental mathematical models agree well with measured values from plant trials. These models and analytical equations have thereafter been used to predict hydrogen and sulphur refining for new heats. Here, it was shown that these analytical predictions give very similar results as the fundamental predictions. Thus, it is possible to use the analytical equations in production. It is also discussed how the analytical process models can be used both as on-line or off-line tools in industry.
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| 9. |
- Stein, G.J., et al.
(författare)
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Modelling and simulation of a fore-and-aft driver’s seat suspension system with road excitation
- 2008
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 38:5-6, s. 396-409
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a simplified simulation of two configurations of the fore-and-aft seat suspension system. A fore-and-aft suspension system model was proposed based on the laboratory measurements of the seat vibration isolation performance. Friction was identified as an important parameter, so different approaches to simulating the suspension friction were investigated. Predicted seat vibration mitigation properties were compared with those measured in the laboratory in response to the recordings of the fore-and-aft vibration measured at the base of the driver's seat in an on-road tractor-trailer combination (articulated truck). Optimisation of the suspension elements parameters was then performed to identify the maximum attainable attenuation. A solution incorporating supercritical suspension damping predicted to give an improvement of the order of 10% in the x-direction mitigation properties as compared to a fixed (locked) horizontal suspension system.Relevance to the industry: Simulations conducted in this study are of use to seat manufacturers in developing the fore-and-aft seat suspension systems with improved vibration mitigation properties and for predicting its dynamic performance. The optimisation study shows the attainable vibration mitigation limits for a horizontal suspension system.
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