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- Abdel-Khalek, N.A., et al.
(författare)
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Effect of starch type on selectivity of cationic flotation of iron ore
- 2012
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Ingår i: Mineral Processing and Extractive Metallurgy. - 0371-9553 .- 1743-2855. ; 121:2, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- Cationic flotation is one of the most widely accepted technologies for upgrading siliceous iron ore using polysaccharides (mainly starches) as depressing agents for iron bearing minerals while floating silica with amines. In this paper, a group of starches are investigated as depressants for haematite. These starches are wheat, corn, rice, potato and dextrin. The role of starch type on the selectivity of the separation process has been studied through zeta potential, adsorption measurements as well as flotation tests. The effects of type of starch and pH of the medium have been studied. The results indicate that the selectivity of the separation process is strongly affected by the type of starch used, where better results are obtained with corn starch or wheat starch in comparison to the other types. Fourier transform infrared spectroscopy measurements indicated that the interaction between starches and haematite surface is intermolecular interaction.
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- Abhale, Prakash Bansi, et al.
(författare)
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Efficient computation of gas flow in blast furnace in 3-D
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012. - 9781627480215 ; , s. 722-732
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Konferensbidrag (refereegranskat)abstract
- Blast furnace continues to occupy prominent place among iron making technologies as it accounts for more than 90% of the hot metal produced in the world. In India, as a part of initiative from Ministry of Steel, efforts are being made to develop offline as well as online models with an aim to improve blast furnace performance. As a part of this effort, offline comprehensive models simulating the internal state of an operating blast furnace are being developed. Such comprehensive models involve systematic integration of various sub-models for gas flow, solid flow, reaction kinetics, enthalpy balance etc. Unlike in many other systems, these sub-processes are highly interlinked in blast furnace and hence call for large number of iteration among the sub-models which ultimately results in significant computation time. Our efforts in integration of these sub-models have indicated that the gas flow is one of the important bottle necks in achieving faster computation. This has led to a development of new and efficient computation scheme to simulate the gas flow in 2-D [1]. This new scheme provided efficient way of handling complex burden profile in a blast furnace. This paper presents the extension of this 2-D gas flow model to 3-D. Further, the 3-D model has been used to investigate the asymmetry in gas flow which can arise from blanking the tuyeres, asymmetric fusion or cohesive zone or formation scabs or scaffolds in the furnace behavior
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- Abitew, Aymiro, et al.
(författare)
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Hydraulic conductivity of tailings sand used for dam construction at Aitik mine in Sweden
- 2012
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Ingår i: SWEMP 2012.
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Konferensbidrag (refereegranskat)abstract
- Distribution of vertical and horizontal hydraulic conductivity and their correlation to geotechnical parameters affecting the hydraulic conductivity of tailings deposit at Aitik mine have been determined. The investigation was carried out along three sections which cover approximately 3km2 of area and 4-5meters of thickness. 3-5 test pits have been excavated in each section and samples are collected from various levels. The horizontal hydraulic conductivity has been found to have a good relation with fraction of fine particles in the deposit and void ratio. However, similar to the results of Jantzer et al (2008) from the same mine, the vertical hydraulic conductivity did not correspond to void ratio. According to evaluation of existing empirical relations to estimate hydraulic conductivity from particle size analysis, Hazen formula (1911) gives 25 and 45 times the measured values of vertical and horizontal hydraulic conductivity respectively. On the other hand, Chapuis et al (2003) has not been succeeded for prediction of hydraulic conductivity of undisturbed samples from the investigated area. However, it gives comparatively good prediction of hydraulic conductivity for disturbed samples which are compacted to their field dry density.
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- Abolmasoumi, Amirhossein, et al.
(författare)
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Observer design for a class of nonlinear delayed systems with unknown inputs and Markovian jump parameters
- 2012
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Ingår i: ICCAS 2012. - 9781467322478 ; , s. 1848-1852
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Konferensbidrag (refereegranskat)abstract
- The problem of full-order observer design for a class of delayed nonlinear systems with unknown inputs and Markovian jumping parameters is considered. The design method is formulated as solving a set of linear matrix inequalities (LMI's). Extending the results of nonlinear observer design to Markovian jump systems with time-varying delays is the main advantages of this paper. The sufficient LMI conditions are dependent on both the upper and lower bounds of delay. The effectiveness of the proposed method is shown via an illustrative example.
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- Abrahamsson, Lena, et al.
(författare)
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Projekt: Framtidsoperatören
- 2012
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Annan publikation (populärvet., debatt m.m.)abstract
- Detta projekt syftar till utveckla en verktygslåda som ger vidgade sinnen, ökad styrka och virtuell förmåga att röra sig fritt i tid och rum för framtidens operatör (process- och produktionsnära personal). Projektet syftar även till att omdefiniera roller, kompetenskrav och organisationsformer för att skapa ökad kommunikation, stöd och förbättrade förutsättningar för decentraliserat beslutsfattande. Projektet inleddes som ett ”A-projekt” 2011-2012 (600 000 kr) och pågår nu som ett ”B-projekt” 2012-2014 (10 milj. kr) med finansiering från VINNOVA. Projektet är ett samarbete med Chalmers. Från LTU medverkar Lena Abrahamsson (forskningsledare), Jan Johansson och Camilla Grane. Forskargruppen vid Chalmers leds av Johan Stahre som också är övergripande projektledare. I projektet ingår även företag som Volvo, LKAB, AstraTech, Boliden, Sandvik, SKF mfl.
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| 10. |
- Abrahamsson, Lena, et al.
(författare)
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Projekt: Genus och jämställdhet i skogsbruket
- 2012
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Annan publikation (populärvet., debatt m.m.)abstract
- Projektet syftade till att utarbeta förslag för ökad jämställdhet inom skogsnäringens arbetsorganisationer. Projektet pågick 2011 och var ett uppdrag från Landsbygdsdepartementet och ingick i den nationella jämställdhetsstrategin för skogsbrukssektorn som togs fram 2010-2011. I projektet medverkade doktorand Kristina Johansson och Lena Abrahamsson (LTU) samt forskargrupp vid SLU, Umeå.
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