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  • 101.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    Du, Sichen
    Possibility of Sulfur Removal from Ladle Slag by Oxidation in the Temperature Range 1373-1673 K2015In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 1, no 3, p. 229-239Article in journal (Refereed)
    Abstract [en]

    Experiments were conducted to investigate the possibility of removing sulfur from used ladle slag by oxidation. Slag samples (solid, two-phase mixture, and liquid with a small fraction of solid MgO particles) were subjected to an oxygen-rich atmosphere in the temperature range 1373–1673 K. The sulfur removal from the samples of solid and two-phase mixture was found to be a slow process due to the slow diffusion. The sulfur removal was found to have little dependence on temperature in the range 1373–1573 K. When the slag was mostly liquid (at 1673 K), the sulfur removal was significantly increased. More than 85 % of the sulfur could be removed after 60 min of oxidation in pure oxygen. An increase in oxygen partial pressure was found to increase the desulfurization slightly. Increasing the Al2O3 content in the slag decreased the degree of sulfur removal.

  • 102.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    Du, Sichen
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent SpeciesManuscript (preprint) (Other academic)
  • 103.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    Kojola, Niklas
    Hui, Wang
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    A Study of Nitrogen Pickup from the Slag during Waiting Time of Ladle Treatment2014In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 85, no 4, p. 689-696Article in journal (Refereed)
    Abstract [en]

    An investigation of the nitrogen pickup of liquid steel from ladle slag after vacuum degassing was made. Nitride capacities, C-N, of a number of ladle slags were determined at controlled nitrogen and oxygen potentials at 1873K. The nitride capacities in the composition range studied were found to be very low. In accordance with the literature, the nitride capacity was found to increase with increasing SiO2 content. Industrial trials were performed. The nitrogen content of the steel was determined before and after vacuum degassing as well as after the waiting period. Three different trends of the variation of nitrogen content in the steel were observed. Both the laboratory study and the industrial trials revealed that the transfer of nitrogen from slag to steel was not the reason for nitrogen pickup in the steel subsequent to vacuum degassing.

  • 104.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Li, Fan
    White, Jesse F.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Effect of carbon on the solubility of nitrogen in slag2015In: International Journal of Materials Research - Zeitschrift für Metallkunde, ISSN 1862-5282, E-ISSN 2195-8556, Vol. 106, no 8, p. 822-830Article in journal (Refereed)
    Abstract [en]

    The effect of carbon on nitrogen solubility in slag was investigated for the ternary CaO-MgO-SiO2 and the quaternary Al2O3-CaO-MgO-SiO2 slag systems at 1 873 K under controlled oxygen and nitrogen potentials. Gas-slag equilibration experiments were conducted using molybdenum and graphite crucibles. In the absence of carbon, the nitrogen solubility was very low. The presence of carbon greatly increased the nitrogen solubility in slag. The total nitrogen content was found to increase with SiO2 and MgO concentration for the carbon saturated slags. Low levels of cyanide were found by wet chemistry with considerable uncertainty. The results analyzed by different methods ruled out cyanide formation being the main reason for the large increase in nitrogen solubility in the presence of pure carbon.

  • 105.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Selleby, Malin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent Species2016In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 47, no 5, p. 3039-3045Article in journal (Refereed)
    Abstract [en]

    The dependence of sulfide capacity on the oxygen partial pressure for slags containing multivalent species was investigated experimentally using a slag containing vanadium oxide. Copper-slag equilibration experiments were carried out at 1873 K (1600 A degrees C) in the approximate oxygen partial pressure range 10(-15.4) to 10(-9) atm. The sulfide capacity was found to be strongly dependent on the oxygen potential in this slag system, increasing with the oxygen partial pressure. The sulfide capacity changed by more than two orders of magnitude over the oxygen partial pressure range. The effect of changing oxygen partial pressure was found to be much greater than the effect of changing slag composition at a fixed oxygen partial pressure.

  • 106.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sulfide Capacity in Ladle Slag at Steelmaking Temperatures2015In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 46, no 6, p. 2609-2615Article in journal (Refereed)
    Abstract [en]

    Sulfide capacity measurements were conducted at 1823 K and 1873 K (1550 degrees C and 1600 degrees C) for the quaternary Al2O3-CaO-MgO-SiO2 system, for typical compositions used in the ladle in steelmaking. A copper-slag equilibrium was used under controlled oxygen and sulfur potentials. The sulfide capacity is strongly dependent on the composition and it was found to increase with the basic oxides, while it decreases with increase of the acidic components. It was found that CaO is more effective in holding sulfur in the slag compared to MgO when replacing SiO2. For the present slag compositions, Al2O3 and SiO2 behaved similar with respect to sulfur, and no considerable effect could be recorded when replacing one for the other. The sulfide capacity was also found to be strongly dependent on the temperature, increasing with temperature. The present results were compared with industrial data from the ladle, after vacuum treatment, and they were in good agreement.

  • 107.
    Allertz, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    White, J. F.
    Du, Sichen
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Nitrogen solubility and the effect of carbon in ladle slag at 1873 K2015In: Proceedings of the 6th International Congress on the Science and Technology of Steelmaking, ICS 2015, Chinese Society for Metals , 2015, p. 316-319Conference paper (Refereed)
    Abstract [en]

    The solubility of nitrogen in ladle slag was determined at 1873K under controlled nitrogen and oxygen potentials. Gas- slag equilibrium experiments were conducted using molybdenum and graphite crucibles. In the absence of carbon, the nitrogen solubility was very low. The presence of carbon greatly increased the nitrogen solubility in the slag. Low levels of cyanide was detected by wet chemistry, with considerable uncertainty. Cyanide was ruled out as the main reason for the large increase of nitrogen in the presence of pure carbon. The nitrogen solubility was found to increase with increasing SiO2 content both in the absence and presence of carbon.

  • 108. Alm, Hajer Kamal
    et al.
    Ström, Göran
    Karlström, Katarina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Effect of excess dispersant on surface properties and liquid interactions on calcium carbonate containing coatings2010In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 25, no 1, p. 82-92Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to identify what effects excess amount of sodium polyacrylate, a commonly used dispersant, has on the coating properties and the interaction between ink and the paper coating in offset printing. Since polyacrylate strongly interacts with calcium ions, soluble calcium salt was added to some coating colours to illustrate the impact of charge neutralization by calcium ions. It was found that the coating structure was only slightly affected by the extra addition of polyacrylate, showing some weak flocculation, whereas the surface chemistry was strongly influenced. The coatings became more polar and interacted more strongly with water. This resulted in slower ink setting and reduced ink-paper coating adhesion, especially in the presence of applied water/dampening solution, which are identified as contributory factors in ink piling and print mottle.

  • 109. Almcrantz, M.
    et al.
    Andersson, Margareta A.T.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Determination of inclusion characteristics in the Asea-SKF process using the modified spark-induced OES technique as a complement in studying the influence of top slag composition2005In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 76, no 9, p. 624-634Article in journal (Refereed)
    Abstract [en]

    The spark-induced modified optical emission spectroscopy (OES) technique developed by Ovako Steel makes it possible to rapidly determine inclusion characteristics in steel samples. In earlier investigations using the modified spark-induced OES technique for steel samples taken from billets, predicted oxygen contents agreed well with results from conventional melt extraction analyses. In this investigation, samples taken during ladle treatment in an ASEA-SKF ladle furnace were analysed using the modified OES technique. When comparing the results with inclusion characteristics determined by conventional analysis, similar trends were found. Plant trials were also carried out where three different top slag compositions were used. The purpose was to evaluate if the modified OES technique can be used to study the effect of changes in the refining operation on inclusion characteristics. Results indicated that the modified OES technique could be used to determine the effect of a changed slag composition on the inclusion characteristics in the steel. Since the modified OES method provides rapid feedback of inclusion characteristics, it has the potential of being used for faster optimisation of ladle refining operations.

  • 110. Almgren, Karin
    et al.
    Gamstedt, Kristofer E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nygård, P.
    Malmberg, F.
    Lindblad, J.
    Lindström, M.
    Role of fibre-fibre and fibre-matrix adhesion in stress transfer in composites made from resin-impregnated paper sheets.2009In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 29, no 5, p. 551-557Article in journal (Refereed)
    Abstract [en]

    Paper-reinforced plastics are gaining increased interest as packaging materials, where mechanical properties are of great importance. Strength and stress transfer in paper sheets are controlled by fibre-fibre bonds. In paper-reinforced plastics, where the sheet is impregnated with a polymer resin, other stress-transfer mechanisms may be more important. The influence of fibre-fibre bonds on the strength of paper-reinforced plastics was therefore investigated. Paper sheets with different degrees of fibre-fibre bonding were manufactured and used as reinforcement in a polymeric matrix. Image analysis tools were used to verify that the difference in the degree of fibre-fibre bonding had been preserved in the composite materials. Strength and stiffness of the composites were experimentally determined and showed no correlation to the degree of fibre-fibre bonding, in contrast to the behaviour of unimpregnated paper sheets. The degree of fibre-fibre bonding is therefore believed to have little importance in this type of material, where stress is mainly transferred through the fibre-matrix interface.

  • 111.
    Almgren, Karin M.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Wood-fibre composites: Stress transfer and hygroexpansion2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wood fibres is a type of natural fibres suitable for composite applications. The abundance of wood in Swedish forests makes wood-fibre composites a new and interesting application for the Swedish pulp and paper industry. For large scale production of composites reinforced by wood fibres to be realized, the mechanical properties of the materials have to be optimized. Furthermore, the negative effects of moisture, such as softening, creep and degradation, have to be limited. A better understanding of how design parameters such as choice of fibres and matrix material, fibre modifications and fibre orientation distribution affect the properties of the resulting composite material would help the development of wood-fibre composites.

    In this thesis, focus has been on the fibre-matrix interface, wood-fibre hygroexpansion and resulting mechanical properties of the composite. The importance of an efficient fibre-matrix interface for composite properties is well known, but the determination of interface properties in wood-fibre composites is difficult due to the miniscule dimensions of the fibres. This is a problem also when hygroexpansion of wood fibres is investigated. Instead of tedious single-fibre tests, more straightforward, macroscopic approaches are suggested. Halpin-Tsai’s micromechanical models and laminate analogy were used to attain efficient interface characteristics of a wood-fibre composite. When Halpin-Tsai’s model was replaced by Hashin’s concentric cylinder assembly model, a value of an interface parameter could be derived from dynamic mechanical analysis. A micromechanical model developed by Hashin was used also to identify the coefficient of hygroexpansion of wood fibres. Measurements of thickness swelling of wood-fibre composites were performed. Back-calculation through laminate analogy and the micromechanical model made it possible to estimate the wood-fibre coefficient of hygroexpansion. Through these back-calculation procedures, information of fibre and interface properties can be gained for ranking of e.g. fibre types and modifications.

    Dynamic FT-IR (Fourier Transform Infrared) spectroscopy was investigated as a tool for interface characterization at the molecular level. The effects of relative humidity in the test chamber on the IR spectra were studied. The elastic response of the matrix material increased relative to the motion of the reinforcing cellulose backbone. This could be understood as a stress transfer from fibres to matrix when moisture was introduced to the system, e.g. as a consequence of reduced interface efficiency in the moist environment. The method is still qualitative and further development is potentially very useful to measure stress redistribution on the molecular level.

  • 112.
    Almgren, Karin M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gamstedt, E. Kristofer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Characterization of interfacial stress transfer ability by dynamic mechanical analysis of cellulose fiber based composite materials2010In: Composite interfaces (Print), ISSN 0927-6440, E-ISSN 1568-5543, Vol. 17, no 9, p. 845-861Article in journal (Refereed)
    Abstract [en]

    The stress transfer ability at the fiber-matrix interface of wood fiber composites is known to affect the mechanical properties of the composite. The evaluation of interface properties at the level of individual fibers is however difficult due to the small dimensions and variability of the fibers. The dynamical mechanical properties of composite and constituents, in this case wood fibers and polylactide matrix, was here used together with micromechanical modeling to quantify the stress transfer efficiency at the fiber-matrix interface. To illustrate the methodology, a parameter quantifying the degree of imperfection at the interface was identified by inverse modeling using a micromechanical viscoelastic general self-consistent model with an imperfect interface together with laminate analogy on the composite level. The effect of moisture was assessed by comparison with experimental data from dynamic mechanical analysis in dry and moist state. For the wood fiber reinforced polylactide, the model shows that moisture absorption led to softening and mechanical dissipation in the hydrophilic wood fibers and biothermoplastic matrix, rather than loss of interfacial stress transfer ability.

  • 113.
    Almgren, Karin M.
    et al.
    Innventia.
    Gamstedt, E. Kristofer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Berthold, Fredrik
    Innventia.
    Lindström, Mikael
    Innventia.
    Moisture uptake and hygroexpansion of wood fiber composite materials with polylactide and polypropylene matrix materials2009In: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 30, no 12, p. 1809-1816Article in journal (Refereed)
    Abstract [en]

    Effects of butantetracarboxylic acid (BTCA) modification, choice of matrix, and fiber volume fraction on hygroexpansion of wood fiber composites have been investigated. Untreated reference wood fibers and BTCA-modified fibers were used as reinforcement in composites with matrices composed of polylactic acid (PLA), polypropylene (PP), or a mixture thereof. The crosslinking BTCA modification reduced the out-of-plane hygroexpansion of PLA and PLA/PP composites, under water-immersed and humid conditions, whereas the swelling increased when PP was used as matrix material. This is explained by difficulties for the BTCA-modified fibers to adhere to the PP matrix. Fiber volume fraction was the most important parameter as regards out-of-plane hygroexpansion, with a high-fiber fraction leading to large hygroexpansion. Fiber-matrix wettability during processing and consolidation also showed to have a large impact on the dimensional stability and moisture uptake. POLYM. COMPOS., 30:1809-1816, 2009.

  • 114. Almgren, Karin M.
    et al.
    Gamstedt, E. Kristofer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Varna, Janis
    Luleå tekniska universitet, LTU.
    Contribution of wood fiber hygroexpansion to moisture induced thickness swelling of composite plates2010In: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 31, no 5, p. 762-771Article in journal (Refereed)
    Abstract [en]

    One of the main drawbacks of wood fiber-based composite materials is their propensity to swell due to moisture uptake. Because the wood fibers are usually the main contributor to hygroexpansion, it is of interest to quantify the hygroexpansion coefficient of wood fibers, to compare and rank different types of fibers. This investigation outlines an inverse method to estimate the transverse hygroexpansion coefficient of wood fibers based on measurements of moisture induced thickness swelling of composite plates. The model is based on composite micromechanics and laminate theory. Thickness swelling has been measured on polylactide matrix composites with either bleached reference fibers or crosslinked fibers. The crosslinking modification reduced the transverse hygroexpansion of the composites and the transverse coefficient of hygroexpansion of the fibers was reduced from 0.28 strain per relative humidity for reference fibers to 0.12 for cross-linked fibers

  • 115. Almgren, Karin M.
    et al.
    Åkerholm, Margaretha
    Gamstedt, Kristofer
    Salmén, Lennart
    Lindström, Mikael
    Effects of Moisture on Dynamic Mechanical Properties of Wood Fiber Composites Studied by Dynamic FT-IR Spectroscopy2008In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 27, no 16-17, p. 1709-1721Article in journal (Refereed)
    Abstract [en]

    Wood fiber reinforced polylactide is a biodegradable composite where both fibers and matrix are from renewable resources. In the development of such new materials, information on mechanical behavior on the macroscopic and the molecular level is useful. In this study, dynamic Fourier transform infrared (FT-IR) spectroscopy is used to measure losses at the molecular level during cyclic tensile loading for bonds that are characteristic of the cellulosic fibers and the polylactid matrix. This molecular behavior is compared with measured macroscopic hysteresis losses for different moisture levels. The results show that moisture ingress will transfer the load from the fibers to the matrix, and that a more efficient fiber-matrix interface would diminish mechanical losses. Although the dynamic FT-IR spectroscopy method is still qualitative, this investigation shows that it can provide information on the stress transfer of the constituents in wood fiber reinforced plastics.

  • 116.
    Almjashev, V.I.
    et al.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Barrachin, M.
    Institut de Radioprotection et Suˆrete´ Nucle´aire (IRSN).
    Bechta, Sevostian
    AP Aleksandrov Res Inst Technol, Sosnovyi Bor 188540, Russia.
    Bottomley, D.
    European Commission – DG – Joint Research Centre, Institute for Transuranium Elements.
    Defoort, F.
    Laboratoire de Physico-chimie et Thermohydraulique Multiphasiques (LPTM), CEA/Grenoble, DTN/SE2T/LPTM – 17 rue des Martyrs.
    Fischer, M.
    Framatome ANP GmbH.
    Gusarov, V.V.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Hellmann, S.
    Framatome ANP GmbH.
    Khabensky, V.B.
    A.P. Aleksandrov Research Institute of Technology.
    Krushinov, E.V.
    A.P. Aleksandrov Research Institute of Technology.
    Lopukh, D.B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Mezentseva, L.P.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Miassoedov, A.
    Institute for Nuclear and Energy Technologies, Forschungszentrum Karlsruhe.
    Petrov, Yu.B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Vitol, S.A
    A.P. Aleksandrov Research Institute of Technology.
    Eutectic crystallization in the FeO(1.5)-UO(2+x)-ZrO(2) system2009In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 389, no 1, p. 52-56Article in journal (Refereed)
    Abstract [en]

    Results of the investigation of the FeO(1.5)-UO(2+x)-ZrO(2) system in air are presented. The eutectic position and the content of the phases crystallized at this point have been determined. The temperature and the composition of the ternary eutectic are 1323 +/- 7 degrees C and 67.4 +/- 1.0 FeO(1.5), 30.5 +/- 1.0 UO(2+x), 2.1 +/- 0.2 ZrO(2) mol.%, respectively. The solubilities of FeO(1.5) and ZrO(2) in the UO(2+x)(FeO(1.5), ZrO(2)) solid solution correspond to respectively 3.2 and 1.1 mol.%. The solubilities of UO(2) and ZrO(2) in FeO(1.5) are not significant. The existence of a solid solution on the basis of U(Zr)FeO(4) compound is found. The ZrO(2) Solubility in this solid solution is 7.0 mol.%.

  • 117.
    Almjashev, V.I.
    et al.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Barrachin, M.
    Institut de Radioprotection et Suˆrete´ Nucle´aire (IRSN).
    Bechta, Sevostian
    DSAR, AP Aleksandrov Res Inst Technol, NITI, Sosnovyi Bor 188540, Russia .
    Bottomley, D.
    European Commission – DG – Joint Research Centre, Institute for Transuranium Elements.
    Defoort, F.
    Laboratoire de Physico-chimie et Thermohydraulique Multiphasiques (LPTM), CEA/Grenoble, DTN/SE2T/LPTM – 17 rue des Martyrs.
    Fischer, M.
    Framatome ANP GmbH.
    Gusarov, V.V.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Hellmann, S.
    Framatome ANP GmbH.
    Khabensky, V.B.
    A.P. Aleksandrov Research Institute of Technology.
    Krushinov, E.V.
    A.P. Aleksandrov Research Institute of Technology.
    Lopukh, D.B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Mezentseva, L.P.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Miassoedov, A.
    Institute for Nuclear and Energy Technologies, Forschungszentrum Karlsruhe.
    Petrov, Yu.B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Vitol, S.A
    A.P. Aleksandrov Research Institute of Technology.
    Phase equilibria in the FeO(1+x)-UO(2)-ZrO(2) system in the FeO(1+x)-enriched domain2010In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 400, no 2, p. 119-126Article in journal (Refereed)
    Abstract [en]

    Experimental results of the investigation of the FeO(1+x)UO(2)-ZrO(2) system in neutral atmosphere are presented. The ternary eutectic position and the composition of the phases crystallized at this point have been determined. The phase diagram is constructed for the FeO(1+x)-enriched region and the onset melting temperature of 1310 degrees C probably represents a local minimum and so will be a determining factor in this system and its application to safety studies in nuclear reactors.

  • 118.
    Almjashev, V.I.
    et al.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Barrachin, M.
    Institut de Radioprotection et Suˆrete´ Nucle´aire (IRSN).
    Bechta, Sevostian
    A.P. Aleksandrov Research Institute of Technology.
    Bottomley, D.
    European Commission – DG – Joint Research Centre, Institute for Transuranium Elements.
    Vitol, S.A
    A.P. Aleksandrov Research Institute of Technology.
    Gusarov, V.V.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Defoort, F.
    Laboratoire de Physico-chimie et Thermohydraulique Multiphasiques (LPTM), CEA/Grenoble, DTN/SE2T/LPTM – 17 rue des Martyrs.
    Krushinov, E.V.
    A.P. Aleksandrov Research Institute of Technology.
    Lopukh, D.B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Lysenko, A.V.
    Alexandrov Research Institute of Technology, Federal State Unitary Enterprise.
    Martynov, A.P.
    St. Petersburg Electrotechnical University.
    Mezentseva, L.P.
    Institute of Silicate Chemistry of Russian Academy of Sciences.
    Miassoedov, A.
    Institute for Nuclear and Energy Technologies, Forschungszentrum Karlsruhe.
    Petrov, Yu. B.
    Saint-Petersburg Electrotechnical University ‘LETI’.
    Fischer, M.
    Framatome ANP GmbH.
    Khabensky, V.B.
    A.P. Aleksandrov Research Institute of Technology.
    Hellmann, S.
    Framatome ANP GmbH.
    Ternary eutectics in the systems FeO-UO2-ZrO2 and Fe2O3-U3O8-ZrO212011In: Radiochemistry, ISSN 1066-3622, Vol. 53, no 1, p. 13-18Article in journal (Refereed)
    Abstract [en]

    The systems FeO–UO2–ZrO2 (in inert atmosphere) and Fe2O3–U3O8–ZrO2 (in air) were studied. Forthe FeO–UO2–ZrO2 system, the eutectic temperature was found to be 1310°С, with the following componentconcentrations (mol %): 91.8 FeO, 3.8 UO2, and 4.4 ZrO2. For the Fe2O3–U3O8–ZrO2 system, the eutectictemperature was found to be 1323°С, with the following component concentrations (mol %): 67.4 FeO1.5,30.5 UO2.67, and 2.1 ZrO2. The solubility limits of iron oxides in the phases based on UO2(ZrO2,FeO) andUO2.67(ZrO2,FeO1.5) were determined

  • 119. Al-Naamani, Laila
    et al.
    Muthukrishnan, Thirumahal
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM. KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dobretsov, Sergey
    Antifouling properties or chitosan coatings on plastic substrates2019In: Journal of Agricultural and Marine Sciences, Vol. 23, no 1, p. 92-98Article in journal (Refereed)
  • 120.
    Al-Saadi, Munir
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Microstructures and mechanical properties: Forged vs rolled bar in Sanmac 22052016In: Stainless Steel World, ISSN 1383-7184, Vol. 28, no July/August, p. 45-48Article in journal (Refereed)
  • 121.
    Al-Saadi, Munir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Sandberg, Fredrik
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jonsson, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Microstructure characterisation in alloy 8252018Conference paper (Refereed)
  • 122.
    Al-Saadi, Munir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Sandberg, Fredrik
    Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression2018In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October, 2018, article id 114Conference paper (Refereed)
  • 123.
    Al-Saadi, Munir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing. R&D, AB Sandvik Materials Technology, SE-811 81Sandviken, Sweden..
    Sandberg, Fredrik
    R&D, AB Sandvik Materials Technology, SE-811 81Sandviken, Sweden..
    Hulme-Smith, Christopher
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    A study of the static recrystallization behaviour of cast Alloy 825 after hot-compressions2019In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Journal of Physics, Vol. 1270Article in journal (Refereed)
    Abstract [en]

    The static recrystallization behaviour of a columnar and equiaxed Alloy 825 material was studied on a Gleeble-3800 thermo-simulator by single-hit compression experiments. Deformation temperatures of 1000-1200 °C, a strain of up to 0.8, a strain rate of 1s-1, and relaxation times of 30, 180, and 300 s were selected as the deformation conditions to investigate the effects of the deformation parameters on the SRX behaviour. Furthermore, the influences of the initial grain structures on the SRX behaviors were studied. The microstructural evolution was studied using optical microscopy and EBSD. The EBSD measurements showed a relaxation time of 95 % for fractional recrystallization grains, 𝑡95, in both structures, was less than 30 seconds at the deformation temperatures 1100 °C and 1200 °C. However, fewer than 95% of recrystallized grains recrystallized when the deformation temperature was lowered to 1000 °C. From the grain-boundary misorientation distribution in statically recrystallized samples, the fraction of high-angle grain boundaries decreased with an increasing deformation temperature from 1000 °C to 1200 °C for a given relaxation time. This was attributed to grain coarsening

  • 124. Altimira, M.
    et al.
    Fuchs, Laszlo
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Numerical investigation of throttle flow under cavitating conditions2015In: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 75, p. 124-136Article in journal (Refereed)
    Abstract [en]

    The present paper shows the importance of the resolution of large unsteady flow structures in numerical simulations of cavitating flows. Three-dimensional simulations of the flow through a throttle geometry representative for fuel injectors have been performed to characterise the inception and development of cavitation, adopting the implicit Large Eddy Simulation approach. The two-phase flow has been handled by the Volume of Fluid method; whilst the simplified Rayleigh equation has been adopted to handle bubble dynamics. The mathematical model has been solved in the open source C++ toolbox OpenFOAM 2.0.1. Results obtained with the mathematical model are compared with those from RANS-based simulations and validated against experimental measurements. The performed Large Eddy Simulations not only are able to reproduce vortex cavitation, but also give further insight into the complex interaction between cavitation and turbulence through the assessment of the different terms of the vorticity equation.

  • 125. Altincekic, T. G.
    et al.
    Boz, I.
    Baykal, A.
    Kazan, S.
    Topkaya, R.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis and characterization of CuFe2O4 nanorods synthesized by polyol route2010In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 493, no 1-2, p. 493-498Article in journal (Refereed)
    Abstract [en]

    Uniform, high quality, CuFe2O4 nanorods with high aspect ratios were synthesized by a surfactant-free single step polyol process at 220 degrees C. The structure of the product was characterized by XRD and FT-IR, and the morphology of the product was analyzed by SEM. The results showed that the as-prepared nanorods have a uniform cross-section and with average diameter of similar to 100 nm and aspect ratio in the range of 13-52. X-ray line profile fitting resulted in crystallite size of 15 nm, which reveals the polycrystalline nature of these nanorods. Magnetic characterization of product was performed by EPR and VSM techniques and the results show that the CuFe2O4 nanorods are ferromagnetic. The line width of the resonance lines in FMR is about 1.8 kOe which may originate from different resonance fields of randomly distributed nanocrystals which have different orientation of magnetic easy axes.

  • 126.
    Altzar, Oskar
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Crack initiation in hydro power plant rotor rim sheets: A failure case study for Juktan hydro power plant2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2013, cracks were found in the radius of the dovetail slots of the rotor rim sheets in generator 1 of Juktan hydro power plant in Västerbotten, Sweden. The cracks were estimated to be too deep to be able to repair and Alstom conducted an investigation on the cause of fracture. The investigation came to the conclusion that the radius was too small and that the new rotor rim sheets should have a six times greater fillet radius. However, it has not been investigated whether the material structure or the manufacturing process may have an impact on the crack initiation and following propagation that is the focus of this report.Parts of the dovetail slots were cut out and characterized with XRF, SEM and LOM. Further mechanical characterizations were done according to Vickers.From the SEM and LOM micrographs a high amount of large (10μm) and cubic particles were found in the microstructure. The micrographs also showed a deformation of the microstructure and the hardness test showed a deformation hardening near the edge where the sheet had been punched. The edge surface of the sheet also had notches.The large and hard particles in the microstructure impair the mechanical properties of the steel. Furthermore, the hardening effect combined with the notches will make a good crack initiation point. Therefore, there is a higher possibility that a crack will initiate in the radius of the dovetail slots where large stresses occur.

  • 127.
    Altzar, Oskar
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Mechanical Metallurgy.
    Surface Characteristics and Their Impact on Press Joint Strength2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Press fitting is a commonly used method in the assembly of shafts and gearwheels in gearboxes andare using the friction created between them to hold them together. To increase productivity Scania CVAB in Södertälje, Sweden, are going to replace the current hard machining method for layshafts. Whiletesting the new methods in rig it occurred that the gearwheel slipped in tangential direction towardsthe layshaft at a lower torque then with the current method even through all requirements on thelayshafts surface was meet. The purpose and aim with this study is to investigate differences betweenthe methods and to find new requirements for the layshaft. The torque of slip, (Ms) established in atorque test rig and analysis of surface roughness, hardness and microstructure conducted of both thelayshafts and gearwheels. The characteristics of the layshaft surface was also analysed and comparedbetween the different hard machining methods. The study concludes that no correlation between thesurface parameters and the Ms occurred and no major differences in the material between themethods. The study also concluded that the Ms between the layshaft and gearwheel is lower if thelayshaft surface is harder and smoother than the gearwheel surface.

  • 128.
    Ameen, Ahamed
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Optimization of annealing parameters for SANDVIK 13C26 and 20C strip steels: By MODDE analysis and modified JMAK method2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The process optimization of continuous annealing furnace, RHF 125, for recrystallization annealing of two steel grades, Sandvik 13C26 and Sandvik 20C has been carried out. To recreate the continuous annealing process carried out in the roller hearth furnace in the industry, samples with different cold reduction rates were chosen from ongoing production lines. An experimental heat treatment model was chosen by the ‘Design of Experiments’ approach from MODDE (from U-Metrics). The annealing temperature was chosen below the austenitization temperature for both steel grades and soaking time of 30 seconds to 240 seconds were chosen. Microscopic estimation of fraction recrystallized was performed with the help of Electron Back Scattered Diffraction, accompanied by mechanical testing methods to measure the hardness and yield strength of the steel strips. The experimental output was used to create a model to correlate between the different cold reduction rates and annealing parameters to achieve a higher degree of recrystallization along with desirable mechanical properties. Also, a modified Johnson-Mehl-Avrami-Kolomogrov model, based on hardness values, to determine the transformation kinetics by tracking the progress of recrystallization was developed. The model was verified with EBSD measurements for Sandvik 13C26 strip steels. For 20C, inhomogeneous recrystallization was observed, thus limiting the model’s adaptability to steels which exhibit homogeneous recrystallization behavior and negligible change in precipitation and/or coarsening of secondary phases.

  • 129.
    Aminlashgari, Nina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Pal, Jit
    Sanwaria, Sunita
    Nandan, Bhanu
    Srivastava, Rajiv K.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Degradation product profiles of melt spun in situ cross-linked poly(epsilon-caprolactone) fibers2015In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 156, p. 82-88Article in journal (Refereed)
    Abstract [en]

    In situ cross-linking of poly(epsilon-caprolactone) (PCL) fiber with bis-(epsilon-caprolactone-4-yl) (BCY) was shown to be a feasible approach to compensate for reduction in molar mass of PCL during melt-spinning. The effect of in situ cross-linking on the degradation profile of melt spun PCL fibers with different amounts of BCY was evaluated using electrospray ionization-mass spectrometry. Degradation of the cross-linked fibers was carried out in aqueous medium at 37 degrees C and 60 degrees C for different periods of time. The degradation profiles were then compared with uncross-linked fiber and 3D porous cross-linked film of PCL Interesting differences in the degradation product profiles with linear, cyclic or BCY-related low molar mass compounds were observed, clearly demonstrating the effect of cross-linking and processing on the degradation process and formation of water-soluble products. In addition the degradation product profiles demonstrated that in situ cross-linking is a feasible technique for counteracting degradation reactions during melt-spinning.

  • 130.
    Aminzadeh, Selda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Valorization of Kraft Lignin by Fractionation and Chemical Modifications for Different Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Abstract

    Lignin is one of the most abundant biopolymers. Approximately 70 million tons of technical lignin is generated annually, but only little is used for products other than energy. The complexity of lignin hinders full utilization in high-value products and materials. In spite of the large recent progress of knowledge of lignin structure and biosynthesis, much is still not fully understood, including structural inhomogeneity. We made synthetic lignin at different pH’s and obtained structural differences that might explain the structural inhomogeneity of lignin.

    Technical lignins from the chemical pulping are available in large scale, but the processes result in alterations, such as oxidation and condensation. Therefore, to utilize technical lignin, modifications, such as fractionation and/or chemical modifications are necessary. Fractionation with ceramic membranes is one way to lower the polydispersity of lignin. The main advantage is their tolerance towards high temperature and harsh conditions. We demonstrated that low Mw lignin was extracted from industrially produced LignoBoost lignin aiming: i) to investigate the performance of the membrane over time; ii) to analyze the antioxidant properties of the low Mw lignin.

    Chemical modification can also improve the properties of lignin. By adding moieties, different properties can be obtained. Amination and methacrylation of kraft lignin were performed, as well as lignin-silica hybrid materials with potential for the adsorption were produced and investigated.

    Non-modified and methacrylated lignin were used to synthesize lignin-St-DVB porous microspheres to be utilized as a sorbent for organic pollutants. The possibility to substitute styrene with methacrylated lignin was evaluated, demonstrating that interaction between lignin and DVB, and porosity increased.

    Lignin has certain antibacterial properties. Un-modified and modified (aminated) lignin samples and sphere nanoparticles of lignin were tested for their effect against gram-positive and gram-negative bacteria’s and an injectable hydrogel was developed with encapsulated lignin for being used as an injectable gel for the open wounds. Results demonstrated promising antibacterial efficiency of lignins against gram-positive, more especially better inhibition with aminated lignins against gram-positive and negative bacterium.

     

     

    The full text will be freely available from 2019-11-22 11:08
  • 131.
    Aminzadeh, Selda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Zhang, Liming
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    A possible explanation for the structural inhomogeneity of lignin in LCC networks2017In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 51, no 6, p. 1365-1376Article in journal (Refereed)
    Abstract [en]

    Lignin has a very complex structure, and this is partly due to the monomers being connected by many different types of covalent bonds. Furthermore, there are multiple covalent bonds between lignin and polysaccharides in wood, and it is known that the structure of lignin covalently bound to the hemicellulose xylan is different to lignin bound to the hemicellulose glucomannan. Here, synthetic lignin (DHP) is synthesized at different pH and it is shown that lignin made at lower pH has a structure more similar to the lignin bound to xylan, i.e., having higher relative content of beta-O-4 ethers. It is hypothesized that xylan due to its carboxylic acids forms a locally lower pH and thus "direct" the lignin structure to have more beta-O-4 ethers. The biological significance of these results is discussed.

  • 132. Amir, M.
    et al.
    Baykal, A.
    Güner, S.
    Sertkol, M.
    Sözeri, H.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Synthesis and Characterization of CoxZn1−xAlFeO4 Nanoparticles2015In: Journal of Inorganic and Organometallic Polymers and Materials, ISSN 1574-1443, Vol. 25, no 4, p. 747-754Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline powders of cobalt and aluminum co-substituted zinc ferrites with general formula CoxZn1−xAlFeO4 (x = 0.0–1.0) have been synthesized for the first time. Using the citrate-microwave technique and the citric acid as combustion–complexion agent (fuel), materials with spinel mono-phase cubic spinel structure were successfully prepared. The characterization of products was done by XRD, SEM and VSM. The crystallite size estimated by Scherrer formula has been found in the range of 7.7–9.6 nm. The magnetic properties were studied by room temperature (RT) VSM magnetization measurements. The small remanent magnetization (Mr) and coercivity (Hc) values reveal the superparamagnetic nature of nanoparticles (NPs) at RT. The extrapolated saturation magnetization (Ms) is maximum for Co0.8Zn0.2AlFeO4 (17.15 emu/g) and minimum for ZnAlFeO4 particles (4.22 emu/g). This case is attributed to high or low amount of cation distribution change from normal to mixed spinel structure. The average magnetic diameters (Dmag) were calculated from magnetic fit studies of M–H spectra. Dmag values are between 8.17 and 8.46 nm and this range is in great accordance with the obtained diameters from XRD measurements. The small Mr/Ms ratios (maximum, 0.219) specify the uniaxial anisotropy according to Stoner–Wohlfarth model for CoxZn1−xAlFeO4 NPs. RT effective anisotropy constants (Keff) were calculated by using Ms and Hc values. Keff constants increased with increasing Co content in the spinel NPs.

  • 133.
    An, Junxue
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jin, Chunsheng
    Dedinaite, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden.
    Holgersson, Jan
    Karlsson, Niclas G.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden.
    Influence of Glycosylation on Interfacial Properties of Recombinant Mucins: Adsorption, Surface Forces, and Friction2017In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 33, no 18, p. 4386-4395Article in journal (Refereed)
    Abstract [en]

    Interfacial properties of two brush-with-anchor mucins, C-P55 and C-PSLex, have been investigated at the aqueous solution/poly(methyl methacrylate) (PMMA) interface. Both are recombinant mucin-type fusion proteins, produced by fusing the glycosylated mucin part of P-selectin glycoprotein ligand-1 (PSLG-1) to the Fc part of a mouse immunoglobulin in two different cells. They are mainly expressed as dimers upon production. Analysis of the O-glycans shows that the C-PSLex mucin has the longer and more branched side chains, but C-P55 has slightly higher sialic acid content. The adsorption of the mucins to PMMA surfaces was studied by quartz crystal microbalance with dissipation. The sensed mass, including the adsorbed mucin and water trapped in the layer, was found to be similar for these two mucin layers. Atomic force microscopy with colloidal probe was employed to study surface and friction forces between mucin-coated PMMA surfaces. Purely repulsive forces of steric origin were observed between mucin layers on compression, whereas a small adhesion was detected between both mucin layers on decompression. This was attributed to chain entanglement. The friction force between C-PSLex-coated PMMA is lower than that between C-P55-coated PMMA. at low loads, but vice versa at high loads. We discuss our results in terms of the differences in the glycosylation composition of these two mucins.

  • 134.
    Anantha, Krishnan Hariramabadran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Örnek, Cem
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ejnermark, Sebastian
    Medvedeva, Anna
    Sjöström, Johnny
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Correlative Microstructure Analysis and In Situ Corrosion Study of AISI 420 Martensitic Stainless Steel for Plastic Molding Applications2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 4, p. C85-C93Article in journal (Refereed)
    Abstract [en]

    In this work, the corrosion behavior of tempered AISI 420 martensitic stainless steel (MSS) was studied by in-situ atomic force microscopy (AFM) in 0.1M NaCl and correlated with the microstructure. Thermocalc simulation, dilatometry, and X-ray diffraction (XRD) were performed to investigate phase transformation which showed the formation of M3C, M7C3, and M23C6 type of carbides and also retained austenite. Optical microscopy, scanning electron microscopy (SEM), and AFM characterization revealed undissolved carbides and tempering carbides in the martensitic matrix. Volta potential mapping measured by scanning Kelvin probe force microscopy (SKPFM) indicated higher electrochemical (practical) nobility of the carbides with respect to the martensitic matrix whereas regions adjacent to carbides showed lower nobilities due to chromium depletion. Open circuit potential and cyclic potentiodynamic polarization measurements showed metastable corrosion activities associated with a weak passive behavior and a risk for localized corrosion along certain carbide boundaries. In-situ AFM measurements revealed selective dissolution of certain carbide interphases and martensitic inter-lath regions indicating higher propensity to localized corrosion.

  • 135.
    Anderfors, Mikael
    et al.
    Innventia AB, Sweden.
    Llindström, Tom
    Innventia AB, Sweden.
    On the manufacture of carboxymethylated microfibrillated cellulose from different pulp typesManuscript (preprint) (Other academic)
  • 136.
    Anderfors, Mikael
    et al.
    Innventia AB, Sweden.
    Llindström, Tom
    Innventia AB, Sweden.
    Söderberg, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden.
    The use of microfibrillated cellulose in fine paper manufacturing: Results from a pilot scale papermaking trial2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 3, p. 476-483Article in journal (Refereed)
    Abstract [en]

    In this work the strength enhancing capabilities of microfibrillated cellulose (MFC) in highly filled papers was studied. Both the MFC production and the paper making were done in pilot scale under realistic industrial conditions. The results clearly show that MFC (2.5 - 5.0wt-%) could improve the mechanical properties of highly filled papers (20 - 35 wt-% filler contents). All studied dry mechanical properties were improved and the improvements were most pronounced for Z-strength and fracture toughness. By combining the MFC with a C-starch dosage further improvements in mechanical properties could be achieved. The improvements in mechanical properties enabled increased filler content with retained properties. The filler increase could be achieved at the same time as the sheet formation and the dry content after pressing were improved.

  • 137. Andersson, A. J.
    et al.
    Andersson, Margareta A.T.
    KTH, Superseded Departments, Materials Science and Engineering.
    Jonsson, P. G.
    Use of an optimisation model for the burden calculation for the blast furnace process2004In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 33, no 3, p. 172-182Article in journal (Refereed)
    Abstract [en]

    The aim of a burden calculation in the blast furnace process is to compute the amounts of burden materials to be charged for obtaining desired hot-metal and slag composition. Burden calculations are normally based on trial-and-error instead of optimisation. In this study, the use of an optimisation model for a typical blast furnace operation is presented. The yield factors of some components, such as Mn, Si, S, P and V, used in the model have been determined. The more common distribution coefficients have also been studied. Both the yield factor and distribution coefficient values were generally good and showed stable behaviour for repeated periods under similar operational conditions. In this study, the model was found to be an excellent tool for determining burden material amounts and hot-metal and slag compositions for a blast furnace under steady and normal operation conditions. Using an optimising burden calculation model is time efficient, because it demands only 1 calculation procedure instead of a couple calculations as in the case with a trial-and-error method.

  • 138.
    Andersson, Annika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Andersson, Margareta A.T.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    A study of some elemental distributions between slag and hot metal during tapping of the blast furnace2004In: Steel research, ISSN 0177-4832, Vol. 75, no 5, p. 294-301Article in journal (Refereed)
    Abstract [en]

    This paper investigates the distribution of elements between slag and hot metal from a blast furnace through calculation of distribution coefficients from actual production data. First, samples of slag and hot metal tapped from a commercial blast furnace were taken continually at 10-minute intervals for a production period of 68 hours. Distribution coefficients of manganese, silicon, sulphur and vanadium were then calculated from the results of the sample analyses. A major conclusion drawn from examination of the results was that the behaviour of the studied elements was as could be expected when approaching the equilibrium reactions from thermodynamic theory. The distributions of the elements in the slag-metal system showed clear tendencies which did not appear to be influenced by the operational conditions of the furnace. For example, for manganese, vanadium and sulphur, it was found that a higher basicity led to a decreased distribution coefficient L-Mn and L-V, but an increased L-S, which is according to theory. Another observed relationship was that slag basicity increased with an increased carbon content in the hot metal, which indicated that SiO2 was reduced to [Si] when the oxygen potential decreased. Furthermore, it was found that sulphur and silica behaviour likened that of acidic slag components, while the manganese oxide and vanadium oxide behaviour was similar to that of basic slag components.

  • 139. Andersson, Annika J.
    et al.
    Andersson, Margareta A. T.
    KTH, Superseded Departments, Materials Science and Engineering.
    Jönsson, Pär G.
    KTH, Superseded Departments, Materials Science and Engineering.
    Variation in hot metal and stag composition during tapping of blast furnace2004In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 31, no 3, p. 216-226Article in journal (Refereed)
    Abstract [en]

    To determine the quality of the hot metal and the thermal conditions inside the blast furnace, the composition of the hot metal and slag must be known. Obtaining representative metal and slag samples during tapping is thus highly important to blast furnace operation. The study covered in the present report focused on hot metal and slag composition variation during tapping from a commercial blast furnace. From the results, optimal sampling time points for obtaining elemental concentrations that can be taken as representative for the whole tapping sequence were identified. It was furthermore concluded, that the reliability of hot metal composition data is significantly improved by averaging elemental concentrations determined from two samples, each taken at a particular time point. One sampling, however, was found to be adequate for slag. Results from the study also showed a fairly strong correlation between amounts of silicon and carbon, sulphur and carbon, and silicon and sulphur in the hot metal, while a weaker correlation between hot metal temperature and each of these elements was observed.

  • 140.
    Andersson, Axel
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Built-up edge formation in stainless steel milling2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Milling tests were performed in stainless steel to investigate the formation of built-up edge (BUE). Three variants of tests were conducted which were divided as high-, medium, and low temperature milling tests. These tests were run in the austenitic stainless steel SS2343. The medium temperature milling tests were run in duplex SS2343 and precipitation hardened CORRAX. BUE was found for all tests. With the exception of the high temperature milling tests, BUE was formed locally on the main cutting edge. When milling at higher temperature the BUE covered the entire edge. All inserts used, each with different technologies had the same amount of BUE formation. The tool wear was similar for the CVD-coated inserts used, while the PVD-coated insert suffered less coating detachment along the edge.

     

    Cross sections showed that in addition to BUE, smearing had occurred on the rake face of the inserts, showing that multiple layers of material adhered to the tool surface. Cross sections also showed that the tool wear was similar for the different milling methods, even though it was known that tool failure eventually would be caused by different wear types.

     

    Microhardness tests of the BUE gave results where the austenitic- and duplex stainless steel had in average almost doubled their hardness. Work hardening for CORRAX was lower with an average hardness increase below 9 percent. As CORRAX gave the same amount of BUE formation as the other steels it could be concluded that work hardening did not affect the amount of BUE formation.

     

    For one sample milled at high temperature a new phase had formed on the insert surface. Analysis in EPMA and EDS indicated that it contained chromium, manganese and oxygen. This indicated that the stainless steel had oxidized when milled at higher temperature. When comparing the composition, it was similar for both BUE and the workpiece material SS2343. The only exception was that titanium could be found in the bulk of the BUE, having higher amount when milled at higher temperature. This indicated that the BUE had interacted with the coating, as this was the only source of titanium.

  • 141.
    Andersson, D. C.
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Lindskog, P.
    Larsson, Per-Lennart
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Inverse modeling applied for material characterization of powder materials2015In: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 43, no 5, p. 1005-1019Article in journal (Refereed)
    Abstract [en]

    An investigation is performed concerning the applicability of inverse procedures, using optimization and simple experiments, for characterization of WC/Co powder materials. The numerical procedure is combined with uniaxial die-compaction experiments using an instrumented die, which allows direct measurement of the distribution of radial stress during the experiments. Finite-element (FE) methods and an advanced constitutive description of powder materials are relied upon to model the compaction experiment. Optimization using a surrogate model is used to determine some of the parameters in the constitutive description. These parameters in the material model are said to be found (with some accuracy) if the output from the FE simulation is similar to the experimental data. It is found that even though a complete constitutive description of the powder materials investigated cannot be achieved using this approach, many important material parameters can be determined with good accuracy.

  • 142.
    Andersson, Daniel C.
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.).
    Lindskog, Per
    Staf, Hjalmar
    Larsson, Per-Lennart
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.).
    A Numerical Study of Material Parameter Sensitivity in the Production of Hard Metal Components Using Powder Compaction2014In: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 23, no 6, p. 2199-2208Article in journal (Refereed)
    Abstract [en]

    Modeling of hard metal powder inserts is analyzed based on a continuum mechanics approach. In particular, one commonly used cutting insert geometry is studied. For a given advanced constitutive description of the powder material, the material parameter space required to accurately model the mechanical behavior is determined. These findings are then compared with the corresponding parameter space that can possibly be determined from a combined numerical/experimental analysis of uniaxial die powder compaction utilizing inverse modeling. The analysis is pertinent to a particular WC/Co powder and the finite element method is used in the numerical investigations of the mechanical behavior of the cutting insert.

  • 143.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Korzhavyi, Pavel A.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    First-principles based calculation of binary and multicomponent phase diagrams for titanium carbonitride2008In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 32, no 3, p. 543-565Article in journal (Refereed)
    Abstract [en]

    In this paper we have used a combined first principles and Calphad approach to calculate phase diagrams in the titanium-carbon-nitrogen system, with particular focus on the vacancy-induced ordering of the substoichiometric carbonitride phase, TiCxNy (x + y <= 1). Results from earlier Monte Carlo simulations of the low-temperature binary phase diagrams are used in order to formulate sublattice models for TiCxNy within the compound energy formalism (CEF) that are capable of describing both the low temperature ordered and the high-temperature disordered state. We parameterize these models using first-principles calculations and then we demonstrate how they can be merged with thermodynamic descriptions of the remaining Ti-C-N phases that are derived within the Calphad method by fitting model parameters to experimental data. We also discuss structural and electronic properties of the ordered end-member compounds, as well as short range order effects in the TiCxNy phase.

  • 144.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Korzhavyi, Pavel A.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Thermodynamics of structural vacancies in titanium monoxide from first principles calculations2005In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 71, no 14, p. 144101-Article in journal (Refereed)
    Abstract [en]

    The structure, stability and electronic properties of the low oxygen oxides of titanium, TiOx with 1/3 <= x <= 3/2, have been studied by means of accurate first-principles calculations. In both stoichiometric and nonstoichiometric TiO there are large fractions of vacant lattice sites. These so-called structural vacancies are essential for understanding the properties and phase stability of titanium oxides. Structures with an ordered arrangement of vacancies were treated with a plane wave pseudo-potential method, while calculations for structures with disordered vacancies were performed within the framework of the Korringa-Kohn-Rostoker Green's function technique. The relaxed structural parameters in general compare well with experimental data, though some discrepancies exist for stoichiometric TiO in the ideal B1 structure, i.e., without any vacancies. The equation of state as well as the elastic properties are also derived. A monoclinic, vacancy-containing, structure of stoichiometric TiO is confirmed to be stable at low temperature and pressure. Experimentally a transition from a stoichiometric cubic structure with disordered vacancies to the ideal B1 structure without any vacancies has been observed at high pressure. It is discussed how this experimental observation relates to the present theoretical results for defect-containing and defect-free TiO.

  • 145.
    Andersson, Emma
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Effect of CaF2 in the Slag in Ladle Refining2009In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 80, no 8, p. 544-551Article in journal (Refereed)
    Abstract [en]

    Industrial experiments were conducted in ladle treatment at SSAB Oxelosund aiming at a reduction and even elimination of CaF2 as a component in synthetic slag formers. The effects of the presence of CaF2 on sulphur refining, lining wear as well as types and amount of inclusions were examined. The results of the plant trials indicated that the new slag without CaF2 had enough capacity for sulphur removal. On the other hand, the presence of CaF2 as a flux in the slag resulted in profound lining wear. It was also found that both the number and the types of non-metallic inclusions were not affected by the elimination of CaF2 from synthetic slag. The origins of different types of inclusions were also analysed on the basis of the experimental results. The analysis supported the finding that the presence of CaF2 had little effect on inclusions.

  • 146.
    Andersson, Erik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of argon stirring on separation of oxidic inclusions in the ladle furnace at Sandvik Materials Technology AB2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The effect of gas stirring in the ladle furnace on inclusion content in austenitic and duplex stainless steel has been investigated at Sandvik Materials Technology AB. The effect was mainly investigated by varying duration of stirring time and intensity of stirring. Any effect on inclusion content was determined by examining total oxygen content before and after the ladle treatment, along with mapping the chemical composition, size and size distribution of the inclusions. Any effect on slag composition was also determined. The effect of gas stirring was measured on a number of heats with continuous sampling during normal production. Data regarding oxygen content during the ladle refining process and the duration of the processes was used to determine a quantifiable relationship between stirring time, stirring intensity and resulting change in oxygen content. The result of the investigation was recommendations regarding the use of varied stirring intensities and duration of gas stirring for achieving negative net loss in oxygen content before and after ladle treatment.

  • 147.
    Andersson, Erik
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Johansson, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of driving force in Gibbs energy on the fraction of martensite2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background to this bachelor thesis is an on-going project within the VINN Excellence Center Hero-m. The task in this thesis is to perform a literature survey about the martensite transformation and investigate how the resulting fraction depends on cooling below the Ms-temperature. Instead of calculating the undercooling for each of the known fractions of martensite the driving force will be evaluated. Several efforts have been made through the years to describe the relationships between fraction transformed austenite and temperature. The approaches to the first models were empirical and derived from collections of data regarding the amount of retained austenite at different quenching temperatures. Lately, studies have been made to derive a thermodynamical relationship using how the Gibbs energy is affected by increments in volume transformed austenite. Two equations are derived by calculating the resulting driving force at different known quenching temperatures and the respective percentage transformed martensite found in previous works. The data for the steels used show a characteristic slope when linearised. A trend for the steels which have a high characteristic slope is that they also have a high Ms temperature, and the steels which have a low characteristic slope tend to have a low Ms. Previous relationships which describe the martensitic transformation have considered the importance of the Ms temperature only in it being a starting temperature for the transformation. To further incorporate the Ms temperature in the equations presented, further research of the martensitic transformation is required. The approach in this thesis of using thermodynamically calculated data is a base for further investigation of the range of the martensite transformation.

  • 148. Andersson, G.
    et al.
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    "Steel eco-cycle" - A Swedish cross-pollination environmental research program2013In: Materials Science and Technology Conference and Exhibition 2013, MS and T 2013, Warrendale , 2013, p. 1784-1791Conference paper (Refereed)
    Abstract [en]

    In 2004, Swedish steel industry launched the first truly holistic research program in one of the world's most energy intensive industries with the aim to drastically increase the energy and resource efficiency by governing and reinforce (closing) the loop in the steel life cycle. The inter-disciplinary approach of the program has led to a significant cross-pollination in environmental steel technology and related areas apart from the impact in the educational field. The program, alongside the development of resource-efficient production of steel, has led to offshoots in aluminium remelting industry, recovery of rare earths from magnetic scrap and recovery of lead from CRT glasses. The research efforts led to the successful recovery of vanadium and magnetically important manganese nanoferrites from (waste) steel slags. The results, in fact, even provide insights into declarations of human attitudes, future raw material prognoses, process optimizations and pilot plant trials along with instrument and model developments.

  • 149.
    Andersson, Henrik C.M.
    et al.
    Swedish Institute for Metals Research.
    Sandström, Rolf
    Swedish Institute for Metals Research.
    Segle, P.
    SAQ Kontroll.
    Andersson, Peter
    SAQ Kontroll.
    Creep crackgrowth in ex service weld metal of 0.5CrMoV1999In: Cape 99: Wilderness, Cape province, South Africa, 12-16 April (1999), 1999Conference paper (Refereed)
    Abstract [en]

    Accurate assessment of the integrity of high temperature components will be of ever increasing importance. The reason for this is that many power plants have reached and exceeded their design life and the number of detected defects increases. This is accentuated by the improvement of the methods for non-destructive testing which means that more and smaller defects will be detected. The possibility to assess the influence of defects on the integrity of high temperature components, will be of vital importance to maintain safe and cost effective power plants.

    The aim of the present work is to increase the understanding of the influence of service exposure on the remaining life of components in a high temperature plant. The investigation aims to creep test exserviceweld material, 14MoV 6 3, from a Swedish power plant. Thematerial has been in service for a period of about 80 000 hours at atemperature of 530-540 °C and with a nominal hoop stress of 52MPa.Both uniaxial and compact tension creep tests have been performedat a temperature of 550 °C. The stress range used was between 130MPa and 170 MPa for the uniaxial creep tests. For the creep crack growth tests the reference stress was ranging between 122 MPa and146 MPa.

    A remaining life assessment according to the R5 procedure is included, where material data from the present experimental study is used. The analysis suggests that a defect or a crack with a depth of 2 mm and a length of 5 mm can be left unattended for a season of service under the condition that the service parameters are not changed. A comparison with the assessment of cracks, found in the same plant as the material for the experimental studies came from, and their known extension during service, is included. A parametric study where load level and type of initial defect/crack are varied is also included.

  • 150. Andersson, J.
    et al.
    Raza, S.
    KTH.
    Eliasson, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Surreddi, K. B.
    Solidification of alloy 718, ati 718Plus® and waspaloy2014In: 8th International Symposium on Superalloy 718 and Derivatives 2014, 2014, p. 181-192Conference paper (Refereed)
    Abstract [en]

    Alloy 718, ATI 718Plus® and Waspaloy have been investigated in terms of what their respective solidification process reveals. Differential thermal analysis was used to approach the task together with secondary electron and back scattered electron detectors equipped with an energy dispersive X-ray spectroscopy detector. These experimental methods were used to construct pseudo binary phase diagrams that could aid in explaining solidification as well as liquation mechanisms in processes such as welding and casting. Furthermore, it was seen that Waspaloy has the smallest solidification range, followed by Alloy 718, and finally ATI 718Plus® possessing the largest solidification interval in comparison.

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