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| 2. |
- Ardehed, Angelica, et al.
(författare)
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Divergence within and among Seaweed Siblings (Fucus vesiculosus and F. radicans) in the Baltic Sea
- 2016
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Closely related taxa provide significant case studies for understanding evolution of new species but may simultaneously challenge species identification and definition. In the Baltic Sea, two dominant and perennial brown algae share a very recent ancestry. Fucus vesiculosus invaded this recently formed postglacial sea 8000 years ago and shortly thereafter Fucus radicans diverged from this lineage as an endemic species. In the Baltic Sea both species reproduce sexually but also recruit fully fertile new individuals by asexual fragmentation. Earlier studies have shown local differences in morphology and genetics between the two taxa in the northern and western Bothnian Sea, and around the island of Saaremaa in Estonia, but geographic patterns seemin conflict with a single origin of F. radicans. To investigate the relationship between northern and Estonian distributions, we analysed the genetic variation using 9 microsatellite loci in populations from eastern Bothnian Sea, Archipelago Sea and the Gulf of Finland. These populations are located in between earlier studied populations. However, instead of bridging the disparate genetic gap between N-W Bothnian Sea and Estonia, as expected from a simple isolation-by-distance model, the new populations substantially increased overall genetic diversity and showed to be strongly divergent from the two earlier analysed regions, showing signs of additional distinct populations. Contrasting earlier findings of increased asexual recruitment in low salinity in the Bothnian Sea, we found high levels of sexual reproduction in some of the Gulf of Finland populations that inhabit extremely low salinity. The new data generated in this study supports the earlier conclusion of two reproductively isolated but very closely related species. However, the new results also add considerable genetic and morphological complexity within species. This makes species separation at geographic scales more demanding and suggests a need for more comprehensive approaches to further disentangle the intriguing relationship and history of the Baltic Sea fucoids.
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| 3. |
- Enkirch, Theresa, et al.
(författare)
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Hepatitis A outbreak linked to imported frozen strawberries by sequencing, Sweden and Austria, June to September 2018
- 2018
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Ingår i: Eurosurveillance. - : European Centre for Disease Prevention and Control. - 1025-496X .- 1560-7917. ; 23:41
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Tidskriftsartikel (refereegranskat)abstract
- Between June-September 2018, 20 hepatitis A cases were notified in six counties in Sweden. Combined epidemiological and microbiological investigations identified imported frozen strawberries produced in Poland as the source of the outbreak. Sequence analysis confirmed the outbreak strain IB in the strawberries with 100 % identity and the respective batch was withdrawn. Sharing the sequence information internationally led to the identification of 14 additional cases in Austria, linked to strawberries from the same producer.
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| 4. |
- Ahmed, Hesham, et al.
(författare)
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Alternative Reducing Agents for Sustainable Blast Furnace Ironmaking
- 2017
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Ingår i: ESTAD 2017.
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Konferensbidrag (refereegranskat)abstract
- Lowering of CO2 emission from the integrated steel industry as well as minimizing theneed for landfill are important challenges in the focus for the integrated steel industry. With thisaim collaborative research projects have been conducted and are on-going on the possible useof renewable reducing agents or such with high content of H2 as well as for enabling recyclingof 1in-plant fines so far not possible to use. Due to contents of undesired impurities the blastfurnace (BF) sludge has to be pre-treated in an appropriate way before carbon and iron oxidecan be valorized. In order to understand the impact of alternative reducing agents as injectedthrough the tuyeres or part of top charged agglomerates containing iron oxide, samples oftorrefied biomass, plastic and in-plant fines have been analyzed by means of thermogravimetricanalyzer coupled with a mass spectrometer (TGA-MS).The results proved that effective utilization of carbon bearing BF dust and sludge as analternate reducing agent could be realized and can be implemented into BF after adequateupgrading. Plastic materials and biomass based reductants decomposition is associated with therelease of volatiles. The main contents of these volatiles are CO, H2 and hydrocarbon which areall known for their reduction potential. Moreover, injection of such materials is expected toimprove process efficiency and sustain the gas permeability along the BF cohesive zone. Onthe other hand, top charging of these materials would improve the energy and materialefficiency in the BF due to their higher reactivity compared to conventional carbon.
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| 5. |
- Ahmed, Hesham, et al.
(författare)
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Effect of the Ash from H2‐Rich Carbonaceous Materials on the Physicochemical Properties of Raceway Slag and Coke Reactivity
- 2020
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Ingår i: Steel Research International. - : John Wiley & Sons. - 1611-3683 .- 1869-344X. ; 91:11
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Tidskriftsartikel (refereegranskat)abstract
- The iron and steel industry is one of the most important sectors worldwide, and it has a great impact on the global economy; however, this sector is still highly dependent on fossil carbon. To decrease this dependency, approaches to partially replace the injected pulverized coal with secondary, highly reactive, renewable (biomass) and H2‐rich materials have been studied. The injection of such materials is expected to significantly decrease the emitted CO2 from blast furnaces. However, due to the different ash composition of these alternative materials (especially alkali and alkaline earth metals) compared to that of ordinary injected coal, these materials are expected to alter the raceway slag properties and affect the coke reactivity. In the present article, the effect of the ash from different hydrogen‐rich carbonaceous materials on the raceway slag physicochemical properties as well as coke reactivity is reported. The melting characteristics of the ash briquettes in contact with the coke and wettability of the melted ash on the coke surface are determined visually using an optical heating microscope. The effect of the ash on the coke reactivity is studied by means of thermogravimetry under a continuous flow of CO2.
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| 6. |
- Ahmed, Hesham, et al.
(författare)
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Energy Efficient Recycling of in-Plant Fines
- 2014
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Ingår i: Proceedings of World Academy of Science, Engineering and Technology. - 2010-376X .- 2070-3740. ; 8:6, s. 485-491
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Tidskriftsartikel (refereegranskat)abstract
- Numerous amounts of metallurgical dusts and sludge containing iron as well as some other valuable elements such as Zn, Pb and C are annually produced in the steelmaking industry. These alternative iron ore resources (fines) with unsatisfying physical and metallurgical properties are difficult to recycle. However, agglomerating these fines to be further used as a feed stock for existing iron and steelmaking processes is practiced successfully at several plants but for limited extent.In the present study, briquettes of integrated steelmaking industry waste materials (namely, BF-dust and sludge, BOF-dust and sludge) were used as feed stock to produce direct reduced iron (DRI). Physical and metallurgical properties of produced briquettes were investigated by means of TGA/DTA/QMS in combination with XRD. Swelling, softening and melting behavior were also studied using heating microscope.
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| 7. |
- Ahmed, Hesham, et al.
(författare)
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Reduction Behaviour of Self-reducing Blends of In-plant Fines in Inert Atmosphere
- 2015
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Ingår i: ISIJ International. - 0915-1559 .- 1347-5460. ; 55:10, s. 2082-2089
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Tidskriftsartikel (refereegranskat)abstract
- Large amount of dust and sludge recovered during cleaning of iron and steel making process gases are annually put on landfill or intermediate storage. These by-products have high contents of iron (Fe) and carbon (C) that potentially could be utilized in the steel industry. However, due to the presence of impuritycompounds as well as the unsuitable physical properties, these by-products cannot be recycled directly. The main objective of the present study is to investigate the possibilities to recover the valuable components Fe and C in these by-products and thereby decrease the need of landfills at the steel plants as well as reduce the consumption of virgin materials, including fossil coal, and reduce CO2 emissions. A recycling route has been investigated by means of laboratory trials and FactSage thermodynamic modeling. Four different blends of BF and BOF dusts and sludges are prepared in predetermined ratios. Reduction behavior of each blend is studied using TG/DTA/QMS and in-situ high temperature X-ray diffraction. High temperature physical properties like softening, swelling and melting are also investigated by means of heatingmicroscope. The obtained results indicate the feasibility of both minimizing the impurity elements as well as recovering of valuable components.
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| 8. |
- Ahmed, Hesham, et al.
(författare)
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Utilization of Steelmaking Industry Waste Materials in Producing Direct Reduced Iron
- 2014
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Konferensbidrag (refereegranskat)abstract
- The depletion of coke reserves and the raised environmental concerns motivated researchers to work on alternative iron-making processes. Large amount of metallurgical dusts and sludge containing iron and C are produced in the steelmaking industry. These alternative iron ore resources (fines) with poor hydrophilicity are difficult to recycle. The idea of briquetting such wastes containing iron to be used as a feed stock for steelmaking industry is practiced successfully at several plants.In the present study, agglomerates of integrated steelmaking industry waste materials were used as feed stock to produce direct reduced iron (DRI). The reduction behavior of blends of different waste materials (namely, BF dust and sludge, BOF dust and sludge) were investigated thoroughly utilizing TGA/DTA/QMS in combination with XRD.
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| 9. |
- Andersson, Anton, et al.
(författare)
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A holistic and experimentally-based view on recycling of off-gas dust within the integrated steel plant
- 2018
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Ingår i: Metals. - Basel : MDPI AG. - 2075-4701. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Ore-based ironmaking generates a variety of residues, including slags and fines such as dust and sludges. Recycling of these residues within the integrated steel plant or in other applications is essential from a raw-material efficiency perspective. The main recycling route of off-gas dust is to the blast furnace (BF) via sinter, cold-bonded briquettes and tuyere injection. However, solely relying on the BF for recycling implicates that certain residues cannot be recycled in order to avoid build-up of unwanted elements, such as zinc. By introducing a holistic view on recycling where recycling via other process routes, such as the desulfurization (deS) station and the basic oxygen furnace (BOF), landfilling can be avoided. In the present study, process integration analyses were utilized to determine the most efficient recycling routes for off-gas dust that are currently not recycled within the integrated steel plants of Sweden. The feasibility of recycling was studied in experiments conducted in laboratory, pilot, and full-scale trials in the BF, deS station, and BOF. The process integration analyses suggested that recycling to the BF should be maximized before considering the deS station and BOF. The experiments indicated that the amount of residue that are not recycled could be minimized.
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| 10. |
- Andersson, Anton, et al.
(författare)
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Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments
- 2021
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Konferensbidrag (refereegranskat)abstract
- In the present work, a full factorial design of experiments with three factors was performed studying the evaporation of potassium (K) from synthetic blast furnace (BF) slag. The experiments showed that slag temperature and B2 basicity (%CaO/%SiO2) had the greatest effect on the evaporation kinetics, while the effect of the MgO content was comparatively less. The regression model developed based on the experimental design could describe the evaporation of K from actual BF slags fairly well, provided that they were within the experimental matrix of the design of experiments.
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