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  • 601.
    Fahlén, Jesper
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    The cell wall ultrastructure of wood fibres: effects of the chemical pulp fibre line2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Knowledge of the ultrastructural arrangement within wood fibres is important for understanding the mechanical properties of the fibres themselves, as well as for understanding and controlling the

    ultrastructural changes that occur during pulp processing.

    The object of this work was to explore the use of atomic force microscopy (AFM) in studies of the cell wall ultrastructure and to see how this structure is affected in the kraft pulp fibre line. This is done in order to eventually improve fibre properties for use in paper and other applications, such as composites. On the ultrastructural level of native spruce fibres (tracheids), it was found that cellulose fibril aggregates exist as agglomerates of individual cellulose microfibrils (with a width

    of 4 nm). Using AFM in combination with image processing, the average side length (assuming a square cross-section) for a cellulose fibril aggregate was found to be 15–16 nm although with a broad distribution. A concentric lamella structure (following the fibre curvature) within the

    secondary cell wall layer of native spruce fibres was confirmed. These concentric lamellae were formed of aligned cellulose fibril aggregates with a width of about 15 nm, i.e. of the order of a single cellulose fibril aggregate. It was further found that the cellulose fibril aggregates had a

    uniform size distribution across the fibre wall in the transverse direction.

    During the chemical processing of wood chips into kraft pulp fibres, a 25 % increase in cellulose fibril aggregate dimension was found, but no such cellulose fibril aggregate enlargement occurred during the low temperature delignification of wood into holocellulose fibres. The high temperature in the pulping process, over 100 ºC, was the most important factor for the cellulose fibril aggregate enlargement. Neither refining nor drying of kraft or holocellulose pulp changed the cellulose fibril aggregate dimensions.

    During kraft pulping, when lignin is removed, pores are formed in the fibre cell wall. These pores were uniformly distributed throughout the transverse direction of the wood cell wall. The lamellae consisting of both pores and matrix material (“pore and matrix lamella”) became wider and their numeral decreased after chemical pulping. In holocellulose pulp, no such changes were seen.

    Refining of kraft pulp increased the width of the pore and matrix lamellae in the outer parts of the fibre wall, but this was not seen in holocellulose.

    Upon drying of holocellulose, a small decrease in the width of the pore and matrix lamellae was seen, reflecting a probable hornification of the pulp. Refining of holocellulose pulp led to pore closure probably due to the enhanced mobility within the fibre wall. Enzymatic treatment using

    hemicellulases on xylan and glucomannan revealed that, during the hydrolysis of one type of hemicellulose, some of the other type was also dissolved, indicating that the two hemicelluloses were to some extent linked to each other in the structure. The enzymatic treatment also decreased the pore volume throughout the fibre wall in the transverse direction, indicating enzymatic accessibility to the entire fibre wall.

    The results presented in this thesis show that several changes in the fibre cell wall ultrastructure occur in the kraft pulp fibre line, although the effects of these ultrastructural changes on the fibre properties are not completely understood.

  • 602.
    Fahlén, Jesper
    et al.
    STFI, Swedish Pulp and Paper Res. Inst..
    Salmén, Lennart
    STFI, Swedish Pulp and Paper Res. Inst..
    Cross-sectional structure of the secondary wall of wood fibers as affected by processing2003In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 38, no 1, p. 119-126Article in journal (Refereed)
    Abstract [en]

    Understanding the arrangement of wood polymers within the fiber wall is important for understanding the mechanical properties of the fibers themselves. Due to their high load bearing ability, the arrangement of cellulose fibrils within the cell wall are of special interest. In this work AFM-Atomic Force Microscopy-in combination with image processing has been used to obtain more information about the arrangement of cellulose aggregates (fibrils) in the secondary cell wall layer of spruce wood. The effects of chemical processing on the arrangement of these cellulose aggregates were also studied. Enlargement of cellulose aggregates was found in the initial phase of the kraft cook. This increase in cellulose aggregate dimensions depended mostly on temperature for treatment temperatures above 140degreesC, regardless of the amount of alkali present. Although hemicelluloses are lost to various degrees under alkaline conditions, the increase in cellulose aggregate size was mainly related to thermally induced rearrangement of the cellulose molecules. The mean side length of cellulose aggregates was found to be around 18 nm in unprocessed wood and 23 nm in processed wood. The cellulose aggregates were assumed to be square shaped in cross section in both cases.

  • 603.
    Fahlén, Jesper
    et al.
    STFI, Swedish Pulp and Paper Res. Inst..
    Salmén, Lennart
    STFI, Swedish Pulp and Paper Res. Inst..
    On the Lamellar Structure of the Tracheid Cell Wall2002In: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 4, no 3, p. 339-345Article in journal (Refereed)
    Abstract [en]

    It is clear that cross sections of wood cells show a lamellar structure. This paper investigates the orientation of this lamellar structure of spruce (Picea abies) tracheids using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross sections of spruce wood were produced through fracturing in longitudinal bending and tensile testing. When investigated with SEM, the fracture surfaces show a structure of mostly larger radial lamellae, in the order of 30-100 nm, i.e., agglomerations of a few cellulose aggregates. Thin transverse sections of the fracture zones investigated with atomic force microscopy show concentric lamellae with a width in the order of a single cellulose aggregate, i.e., 15-25 nm. No structural connection to the splinters in the radial direction can be seen. It is suggested that the radial lamellar structure is a consequence of the energy released during fracturing of the wood samples and that the undistorted wood has a concentric lamellar structure on a smaller structural level.

  • 604.
    Fahlén, Jesper
    et al.
    STFI-Packforsk AB.
    Salmén, Lennart
    STFI-Packforsk AB.
    Pore and Matrix Distribution in the Fiber Wall Revealed by Atomic Force Microscopy and Image Analysis2005In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 6, no 1, p. 433-438Article in journal (Refereed)
    Abstract [en]

    A method for the ultrastructural investigation of fiber cross-sections based on atomic force microscopy in combination with image analysis is presented. A uniform distribution of pores across the matrix material within the fiber wall was revealed by impregnation of pulp fibers with poly(ethylene glycol). The effects of chemical and mechanical processing on the pore and matrix structure and on the arrangement of the cellulose fibril aggregates were investigated. During chemical processing, changes in the fiber ultrastructure occur: a broadening of the pore and matrix lamella widths in combination with a reduction in their number and an enlargement of the cellulose fibril aggregates. It was found that pores formed during pulping are evenly distributed across the fiber wall in the transverse direction. In contrast, refining increases the pore and matrix lamella width in the fiber wall closest to the middle lamella an effect which gradually decrease in size toward the lumen side.

  • 605.
    Fahlén, Jesper
    et al.
    STFI-Packforsk AB.
    Salmén, Lennart
    STFI-Packforsk AB.
    Ultrastructural changes in a holocellulose pulp revealed by enzymes, thermoporosimetry and atomic force microscopy2005In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 59, no 6, p. 589-597Article in journal (Refereed)
    Abstract [en]

    To increase our knowledge of the ultrastructure within softwood fibres, enzymatic treatment, thermoporosimetry, light microscopy, and atomic force microscopy with image analysis were used to investigate the structure of holocellulose softwood pulp fibres. The size of the average cellulose fibril aggregates and the width of pore and matrix lamellae were found to be uniform across the secondary cell-wall layer in the transverse direction of the wood fibre wall. In holocellulose, these dimensions were very similar to those in the native wood, whereas in kraft pulp the cellulose fibril aggregates were larger and the pore and matrix lamellae broader. These differences between holocellulose and kraft pulp fibres suggest that a high temperature is needed for cellulose fibril aggregation to occur. Neither refining nor drying of the holocellulose pulp changed the cellulose fibril aggregate size. Upon drying and enzymatic treatment, a small decrease in the pore and matrix lamella width was evident throughout the fibre wall. This indicated not only uniform distribution of pores throughout the fibre wall, but also enzymatic accessibility to the entire fibre wall. The holocellulose pulp had a somewhat larger pore volume than the kraft pulp. Refining of the holocellulose pulp led to pore closure, probably due to increased mobility of the fibre wall. The enzymatic treatment revealed that during hydrolysis of one hemicellulose, part of the other was also dissolved, indicating that the two hemicelluloses are to some extent linked to each other in the structure.

  • 606.
    Fan, Liangdong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Chen, Mingming
    Tianjin University, China.
    Wang, Chengyang
    Tianjin University, China.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Pr2NiO4–Ag composite cathode for low temperature solid oxide fuel cells with ceria-carbonate composite electrolyte2012In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 37, no 24, p. 19388-19394Article in journal (Refereed)
    Abstract [en]

    Pr2NiO4-Ag composite was synthesized and evaluated as cathode component for low temperature solid oxide fuel cells based on ceria-carbonate composite electrolyte. X-ray diffraction analysis reveals that the formation of a single phase K2NiF4-type structure occurs at 1000 °C and Pr2NiO4-Ag composite shows chemically compatible with the composite electrolyte. Symmetrical cells impedance measurements prove that Ag displays acceptable electrocatalytic activity toward oxygen reduction reaction at the temperature range of 500-600 °C. Single cells with Ag active component electrodes present better electrochemical performances than those of Ag-free cells. An improved maximum power density of 695 mW cm-2 was achieved at 600 °C using Pr 2NiO4-Ag composite cathode, with humidified hydrogen as fuel and air as the oxidant. Preliminary results suggest that Pr 2NiO4-Ag composite could be adopted as an alternative cathode for low temperature solid oxide fuel cells.

  • 607.
    Fan, Liangdong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Wang, Chengyang
    Chemical engineering and technology.
    Chen, Mingming
    Di, Jing
    Zheng, Jiaming
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM).
    Potential low-temperature application and hybrid-ionic conducting property of ceria-carbonate composite electrolytes for solid oxide fuel cells2011In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 36, no 16, p. 9987-9993Article in journal (Refereed)
    Abstract [en]

    Ceria-carbonate composite materials have been widely investigated as candidate electrolytes for solid oxide fuel cells operated at 300-600 degrees C. However, fundamental studies on the composite electrolytes are still in the early stages and intensive research is demanded to advance their applications. In this study, the crystallite structure, microstructure, chemical activity, thermal expansion behavior and electrochemical properties of the samaria doped ceria-carbonate (SCC) composite have been investigated. Single cells using the SCC composite electrolyte and Ni-based electrodes were assembled and their electrochemical performances were studied. The SCC composite electrolyte exhibits good chemical compatibility and thermal-matching with Ni-based electrodes. Peak power density up to 916 mW cm(-2) was achieved at 550 degrees C, which was attributed to high electrochemical activity of both electrolyte and electrode materials. A stable discharge plateau was obtained under a current density of 1.5 A cm(-2) at 550 degrees C for 120 min. In addition, the ionic conducting property of the SCC composite electrolyte was investigated using electrochemical impedance spectroscopy technique. It was found that the hybrid-ionic conduction improves the total ionic conductivity and fuel cell performance. These results highlight potential low-temperature application of ceria-carbonate composite electrolytes for solid oxide fuel cells.

  • 608.
    Faramarzi, Simin
    KTH, School of Chemical Science and Engineering (CHE).
    Effect of Alternative Fuels on SCR Chemistry2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the time line of world industrial age, the most important era begins in the late 18th century when the use of fossil fuels was growing intensively. This approach has continued and developed up to the 20th century. Besides, this trend has had side effects like polluting environment. Air pollution is one of the critical issues nowadays that stems from using hydrocarbon fuels.

    One type of the problematic compounds in polluting air is nitrogen oxides that can be produced in combustion process from engines and industrial plants. Different solutions have been suggested to remove air polluting compounds. One method for removing nitrogen oxides is using the mechanism of Selective Catalytic Reduction in silencer of engines. This method has become practical in trucks’ engines.

    Therefore, research on SCR chemistry is important for improving the usage of this method in removing nitrogen oxides. SCR has its own problems when used in trucks. One of the problems is formation of white clumps on pipe wall of silencers using SCR which can cause back pressure in the engines and costs a lot to remove them from engines.

     This report evaluates the effect of alternative fuels on SCR chemistry .Different parameters affecting deposit formation are studied and evaluated. Ethanol is one of the controversial fuels used in engines and acetic acid is one its byproducts. Also, urea and its by products are important materials in SCR chemistry, too. Consequently, the first part of the report studies the influence of acetic acid and Ferrite steel, one of the usual steels in silencers of engines, on urea, biuret and cyanuric acid decomposition. The instruments used in the first part include TGA-DSC (Thermo Gravimetric Analysis-Differential Scanning Calorimetric) which is connected to FTIR (Fourier Transform Infrared Spectroscopy).In the second part of the report, the effect of diesel exhaust and ethanol exhaust on cyanuric acid evaporation rate is evaluated. Cyanuric acid is the main compound forming deposit in silencers. The instrument used in the second part is TGA. The third part consists surveying effect of Adblue, aqueous solution of urea, and additivised Adblue, surfactant added Adblue to improve its efficiency, in a patented rig that is scaled down of a silencer of truck.

    The most important result for the first part includes the effect of Ferrite steel treated with acetic acid that accelerated the decomposition of cyanuric acid. This result can be investigated more in order to be used in silencers to accelerate the decomposition rate of clumps formed. In the second part, it is found out that cyanuric acid evaporates faster under ethanol exhaust than diesel exhaust. The third part’s results shows that in the current assembly of pipes in the rig, Additivised Adblue loses its improved efficiency which is an interesting result for engine welding in order to avoid this type of connection in engines.

  • 609.
    Fasanya, Opeoluw A.
    et al.
    Natl Res Inst Chem Technol, Petrochem Div, Zaria, Nigeria..
    Al-Hajri, Rashid
    Sultan Qaboos Univ, Petr & Chem Engn, Muscat, Oman..
    Ahmed, Omar U.
    Natl Res Inst Chem Technol, Petrochem Div, Zaria, Nigeria..
    Myint, Myo T. Z.
    Sultan Qaboos Univ, Dept Phys, Muscat, Oman..
    Atta, Abdulazeez Y.
    Ahmadu Bello Univ, Dept Chem Engn, Zaria, Nigeria..
    Jibril, Baba Y.
    Ahmadu Bello Univ, Dept Chem Engn, Zaria, Nigeria..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Copper zinc oxide nanocatalysts grown on cordierite substrate for hydrogen production using methanol steam reforming2019In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 44, no 41, p. 22936-22946Article in journal (Refereed)
    Abstract [en]

    Hydrogen production from methanol rather than the traditional source, methane, is considered to be advantageous in ease of transportation and storage. However, the current copper-based catalysts utilized in methanol steam reforming are associated with challenges of sintering at high temperature and production of CO which could poison fuel cells. In addressing these challenges, ZnO nanorods were grown hydrothermally on the surface of cordierite and impregnated with Cu to produce catalysts for methanol steam reforming. The catalysts were characterized using SEM, XRD, FTIR, XPS, BET and Raman Spectroscopy. A fixed-bed reactor was used for testing the catalysts while the reaction products were characterized using a GC fitted with FID and TCD. The effects of temperature, methanol concentration and particle size of catalysts on methanol steam reforming were investigated. The experiments were carried out between 180 and 350 degrees C. CO selectivity of 0% was observed for temperatures between 180 and 230 degrees C for 0.8 MeOH:1H(2)O with an average H-2 selectivity of 98% for that temperature range. XPS showed that the catalyst was relatively unchanged after reaction while Raman spectroscopy revealed coke formation on the catalyst surface for reactions carried out above 300 degrees C. This shows that the catalyst is active and selective for the reaction. Publications LLC. Published by Elsevier Ltd. All rights reserved.

  • 610.
    FAT MAN, CHI
    KTH, School of Chemical Science and Engineering (CHE).
    Korrosion vid svetsfogning med hjälp av transient smältfasteknik2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In many areas of engineering industries there are necessary to bond steel, where traditional bonding processes such as welding and brazing are neither efficient enough nor possible. Alternative technique is transient liquid phase bonding (TLPB). In this study, carbon steel (IRAM 1010/1040) have been welded using transient liquid phase bonding method with Fe-B amorphous as filling material. The joints were performed by induction heating with argon flux, set pressure and different temperature and bonding times. The welded bars were then analysed using optical and scanning electronic microscopy (SEM).

     

    The bars with good microstructures and optimal parameters were then tested with galvanostatic corrosion test against each other and non-welded bar to study the corrosion behaviours.  The study shows that the IRAM 1010 steel corroded slightly faster than the IRAM 1040 but comparing with the non-welded bars, still consider having good corrosion resistance.

     

    In this study, TLP bonding shows to be a relevant method to weld low and medium carbon steel, regarding to the microstructure of the weld, corrosion behaviour, bonding time and temperature.   

  • 611.
    Fateh-Alavi, Kamyar
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Gedde, Ulf W.
    KTH, Superseded Departments, Polymer Technology.
    Effect of stabilizers on surface oxidation of silicone rubber by corona discharge2004In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 84, no 3, p. 469-474Article in journal (Refereed)
    Abstract [en]

    Crosslinked polydimethylsiloxane (PDMS) containing Irganox(R) 1076, Tinuvin(R) 770 or lrganox(R) 565, prepared by swelling PDMS in a solution of one of these stabilizers in n-hexane, was exposed to a corona discharge and the corona exposure time (tau(crit)) to form a brittle, silica-like layer was determined by optical microscopy. The critical corona exposure time showed a linear increase with increasing stabilizer concentration; Tinuvin 770 showed the highest efficiency and Irganox 1076 the lowest. The increase in tau(crit) on corona exposure of the stabilized samples with reference to the value for unstabilized PDMS was similar to that reported earlier for air plasma exposed samples. The efficiency of the stabilizers towards corona-induced surface oxidation of PDMS was also confirmed by X-ray photoelectron spectroscopy.

  • 612.
    Fateh-Alavi, Kamyar
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Gedde, Ulf W.
    KTH, Superseded Departments, Polymer Technology.
    A rapid microwave-assisted solvent extraction method for assessment of stabilizer concentration in crosslinked polydimethylsiloxane2004In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 93, no 5, p. 2185-2192Article in journal (Refereed)
    Abstract [en]

    Crosslinked polyclimethylsiloxanes were prepared containing 0.05 to 0.2 wt % of either a phenolic antioxidant (Irganox(R) 1010) or a hindered amine stabilizer (Tinuvin(R) 144). The stabilizer concentration was assessed by HPLC and UV-Vis spectroscopy of Soxhlet and microwave-assisted solvent extracts. Almost complete recovery of stabilizer was achieved with Soxhlet extraction. High stabilizer recovery was achieved when acetone was used as the solvent in the microwave-assisted extraction. HPLC was shown to be an efficient method for determining the concentration of Irganox 1010. For Tinuvin 144 the selectivity of both UV-Vis spectroscopy and HPLC was poor, leading to imprecise evaluation of the antioxidant concentration. The loss of stabilizer by migration from polymer to hot water (75 and 95degreesC) was monitored for the systems stabilized with Irganox 1010 and the diffusion coefficient of the antioxidant in the polymer was determined.

  • 613. Fathy, Marwa
    et al.
    El Nady, Jehan
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ebrahim, Shaker
    Soliman, Moataz B.
    Kashyout, Abd El-Hady B.
    Quasi-solid-state Electrolyte for Dye Sensitized Solar Cells Based on Nanofiber PMA-PVDF and PMA-PVDF/PEG Membranes2016In: International Journal of Electrochemical Science, ISSN 1452-3981, E-ISSN 1452-3981, Vol. 11, no 7, p. 6064-6077Article in journal (Refereed)
    Abstract [en]

    Novel electrospun membranes quasi-solid electrolytes based on blends of polymethylacrylate (PMA) - polyvinylidene fluoride (PVDF), and PMA-PVDF/PEG (polyethylene glycol) are prepared by electrospinning technique and applied as quasi-solid state electrolytes in dye sensitized solar cells (DSSCs). The membranes are characterized by Fourier transform infrared (FT-IR) spectrophotometer, differential scanning calorimeter (DSC), Scanning electron microscopy (SEM), and Electrochemical impedance spectroscopy. The crystallinity obtained from the DSC data increased with the increase of PVDF wt% in PMA-PVDF blend and then decreased for the PMA-PVDF/PEG membranes. The fully interconnected porous structure of the host polymer membranes of PMA-PVDF (4: 6 wt%) exhibited a high electrolyte uptake reached to similar to 265% and an ionic conductivity of 2.1x10(-3) S cm(-1), which is increased to 406.3%, and 3.2 x 10(-3) S cm(-1), respectively for PMA-PVDF/PEG (4: 6: 4 wt%) membrane. DSSC is assembled by PMA-PVDF(4: 6 wt%) and attained an overall energy conversion efficiency of 6.6% at light intensity of 100 mW cm(-2). The presence of 4 w% PEG in the electrolyte membrane increased the energy conversion efficiency to 7 % giving a promise candidate for scaling up this type of DSSCs.

  • 614.
    Fejzic, Emir
    KTH, School of Chemical Science and Engineering (CHE).
    Utveckling av ny analysmetod för detektion av proteinrester i rengjord produktionsutrustning2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 615.
    Femenia, Marc
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Corrosion Studies of Duplex Stainless Steels with Micrometer Resolution2004In: Journal of Corrosion Science & Engineering, ISSN 1466-8858, E-ISSN 1466-8858, Vol. 6, p. paper 28-Article in journal (Refereed)
    Abstract [en]

    The local corrosion behavior of duplex stainless steel (DSS) is affected by a wide variety of factors. Localized corrosion of DSS frequently starts at micrometer scale inclusions or precipitates, which are often segregated in the austenite-ferrite boundary regions. Moreover, due to the partitioning of the key alloying elements of ferrite (Cr and Mo) and austenite (N and Ni), the local interactions between the phases must also be considered. The aim of this doctoral study was to increase the knowledge about the local dissolution behavior of DSS in acidic-chloride environments. The recent developments of new local probing techniques have opened a new frontier in corrosion science, providing valuable local information not accessible in the past. The local techniques used include electrochemical scanning tunneling microscopy (EC-STM), scanning probe force microscopy (SKPFM), magnetic force microscopy (MFM), and scanning Auger electron Spectroscopy (SAES), all with micrometer or sub-micrometer resolution. With EC-STM, it was possible to monitor local dissolution processes on DSS in situ, and in real time. MFM was capable of imaging the phase distribution in DSS without the need of the traditional surface etching, while SKPFM revealed that the Volta potential difference between the two phases was measurable and significant. SAES showed that the composition gradient at the phase boundaries is narrower than 2 µm. Different types of DSSs have been studied, from low-alloyed DSS to superduplex. Higher contents of Cr, Mo and N strengthened both phases as well as the phase boundaries, resulting in phases having similar corrosion resistance that showed a more uniform dissolution behavior. However, the Volta potential difference between the phases proved to be of the same order for all the DSSs studied. Austenite was in general associated to regions displaying a more noble Volta potential than ferrite, resulting in a higher dissolution rate of the ferrite next to the austenite phase.

  • 616.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Tunable chitosan hydrogels for adsorption: Property control by biobased modifiers2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 196, p. 135-145Article in journal (Refereed)
    Abstract [en]

    A sustainable strategy to fabricate chitosan-based composite hydrogels with tunable properties and controllable adsorption capacity of trace pharmaceuticals was demonstrated. Two biobased modifiers were utilized to tune the properties, nano-graphene oxide (nGO) derived from chitosan via microwave-assisted carbonization and oxidation, and genipin as the crosslinking agent. An increase in genipin content facilitated an increase in the degree of crosslinking as shown by improved storage modulus and decreased swelling ratio. Increasing nGO content changed the surface microtopography of the hydrogel which correlated with the surface wettability. nGO also catalyzed the genipin-crosslinking reaction. The hydrogel was further shown to be an effective adsorbent for a common anti-inflammatory drug, diclofenac sodium (DCF), with the removal efficiency ranging from 91 to 100% after 48 h. DCF adsorption efficiency could be tuned through simple alteration of nGO and genipin concentration, which provides promising potential for this environmental-friendly adsorbent in removal of DCF from pharmaceutical waste water.

  • 617.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Microwave carbonized cellulose for trace pharmaceutical adsorption2018In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 346, p. 557-566Article in journal (Refereed)
    Abstract [en]

    A promising sustainable strategy to valorize cellulose to high-value adsorbents for trace pharmaceuticals, like diclofenac sodium (DCF), in the water is demonstrated. Carbon nanospheres (CN) as the DCF adsorbent were derived from cellulose through a one-pot microwave-assisted hydrothermal carbonization method. CN exhibited efficient DCF removal (100% removal of 0.001 mg/mL DCF in 30 s and 59% removal of 0.01 mg/mL DCF in 1 h). The adsorption kinetics and isotherm data were well-fitted with the pseudo-second-order kinetic model and Langmuir model, respectively. The adsorption process was endothermic and spontaneous as confirmed by the thermodynamic parameters. Multiple characterization techniques including SEM/EDS, FTIR, FTIR-imaging and zeta potential were applied to qualitatively investigate the adsorption process. π-π stacking and hydrogen bonding were proposed as the dominant adsorption interactions. CN also demonstrated effective adsorption capacity towards three other commonly-detected contaminants in the wastewater including ketoprofen (KP), benzophenone (BZP), and diphenylamine (DPA), each bearing partial structural similarity with DCF. The affinity of the contaminants towards CN followed the order DPA > BZP > DCF > KP, which could be explained by the different configurations and chemical units. It was speculated that for DCF and KP, the steric hindrance and electrostatic repulsion produced by dissociated carboxyl groups can impede the adsorption process as compared to DPA and BZP. This methodology could offer further insights into the drug adsorption on the cellulose-derived carbon adsorbents and the use of bioderived carbons for treatment of wastewaters contaminated with pharmaceuticals.

  • 618.
    Feng, Zhaoxuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Simeone, Antonio
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Biobased Nanographene Oxide Creates Stronger Chitosan Hydrogels with Improved Adsorption Capacity for Trace Pharmaceuticals2017In: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 5, no 12, p. 11525-11535Article in journal (Refereed)
    Abstract [en]

    A promising green strategy for the fabrication of fully biobased chitosan adsorbents for wastewater purification is presented. Nanographene oxide (nGO)-type carbon dots were derived from chitosan (nGOCS) or from cellulose (nGOCL) through a two-step process including microwave-assisted hydrothermal carbonization and oxidation. Finally, nGO were evaluated as biobased property enhancers in chitosan hydrogel adsorbents. Macroporous chitosan hydrogels were synthesized by cross-linking with genipin, and the incorporation of nGO into these hydrogels was shown to facilitate the cross-linking reaction leading to more robust 3D cross-linked networks. This was evidenced by the increased storage modulus and by the swelling ratio that decreased from 5.7 for pristine chitosan hydrogel to 2.6 for hydrogel with 5 mg/mL nGOCS and 3.3 for hydrogel with 5 mg/mL nGOCL. As a further proof of the concept the hydrogels were shown to be effective adsorbent for the common anti-inflammatory drug diclofenac sodium (DCF). Here, the addition of nGO promoted the DCF adsorption process leading to 100% removal of DCF after only 5 h. The synergistic effect of electrostatic interactions, hydrogen bonding, and pi-pi stacking could explain the high adsorption of DCF on the hydrogels. The developed biobased CS/nGO hydrogels are thus promising adsorbents with great potential for purification of trace pharmaceuticals from wastewater.

  • 619. Fernandes, Susana C. M.
    et al.
    Freire, Carmen S. R.
    Silvestre, Armando J. D.
    Pascoal Neto, Carlos
    Gandini, Alessandro
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Salmén, Lennart
    Transparent chitosan films reinforced with a high content of nanofibrillated cellulose2010In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 81, no 2, p. 394-401Article in journal (Refereed)
    Abstract [en]

    This paper reports the preparation and characterization of nanocomposite films based on different chitosan matrices and nanofibrillated cellulose (NFC) for the purpose of improving strength properties. The nanocomposite films were prepared by a simple procedure of casting a water-based suspension of chitosan and NFC, and were characterized by several techniques: namely SEM, X-ray diffraction, visible spectrophotometry, TGA, tensile and dynamic-mechanical analysis. The films obtained were shown to be highly transparent (transmittance varying between 90 and 20% depending on the type of chitosan and NFC content), flexible, displayed better mechanical properties, with a maximum increment on the Young's modulus of 78% and 150% for high molecular weight (HCH) and water-soluble high molecular weight (WSHCH) filled chitosans, respectively; and of 200% and 320% for low molecular weight (LCH) and water-soluble filled (WSLCH) chitosans, respectively. The filled films also showed increased thermal stability, with, for example, an increase in the initial degradation temperature (Td(i)) from 227 degrees C in the unfilled LCH film up to 271 degrees C in filled LCHNFC50% nanocomposite films, and a maximum degradation temperature (Tdi) raising from 304 degrees C to 313 degrees C for the same materials.

  • 620.
    Fernandez, Hanna
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Johansson, Tova
    KTH, School of Chemical Science and Engineering (CHE).
    Renholm, Pontus
    KTH, School of Chemical Science and Engineering (CHE).
    Stauber Alfredsson, Malin
    KTH, School of Chemical Science and Engineering (CHE).
    Design och tillverkning av automatiserat bryggverk2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Alkoholhaltiga drycker har konsumerats länge i Sverige, idag är öl en av de mest förekommande dryckerna. Med tanke på hur få ingredienser öl innehåller och att smaken trots detta kan varieras i det oändliga är det lätt att förstå att alla delsteg måste genomföras med precision. De olika delstegen i ölbryggningsprocessen är mältning, mäskning, lakning, humlekokning och jäsning.

    Ett försök till att bygga ett automatiserat bryggverk har gjorts. Komponenter till bryggverket har köpts in och bryggverket har byggts från grunden. Det var inte möjligt att göra alla delsteg i processen automatiserade, till exempel flödesstyrningar och tillsats av ingredienser. Detta gjorde att manuella insatser krävdes. För att styra bryggningen programmerades mikrokontrollerkortet Arduino Uno i programmeringsspråket C. Med hjälp av programmeringen har de delsteg av bryggningen, som går att automatisera, automatiserats.

    Vid testbryggningen uppstod praktiska problem som inte kunde förutsägas i teorin, exempelvis gick pumpen torrt ibland, reläerna fungerade inte som tänkt samt att en oväntad temperaturgradient uppstod. Dessa problem kan eventuellt lösas med ytterligare insatser i framtida försök. Vidare genomfördes tester innan bryggningen med endast vatten i kärlen för att undersöka temperaturregleringen. Det visade sig dock vara stora skillnader mellan vatten och mäsk, vilket gjorde att dessa tester inte kunde förutsäga alla problem. Trots detta resulterade bryggningen i en besk men drickbar öl.

  • 621.
    Ferraris, Sara
    et al.
    Politecnico di Torino.
    Perero, S.
    Politecnico di Torino.
    Miola, M.
    Politecnico di Torino.
    Vernè, E.
    Politecnico di Torino.
    Rosiello, A.
    Aero Sekur S.p.A.
    Ferrazzo, V.
    Aero Sekur S.p.A.
    Valletta, G.
    Aero Sekur S.p.A.
    Sanchez, Javier
    Bactiguard AB.
    Ohrlander, Mattias
    Bactiguard AB.
    Tjörnhammar, Staffan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Fokine, Michael
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, Sweden.
    Skoglund, Sara
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ferraris, M.
    Politecnico di Torino.
    Chemical, mechanical and antibacterial properties of silver nanocluster/silica composite coated textiles for safety systems and aerospace applications2014In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 317, p. 131-139Article in journal (Refereed)
    Abstract [en]

    This work describes the chemical, mechanical and antibacterial properties of a novel silver nanocluster/silica composite coating, obtained by sputtering, on textiles for use in nuclear bacteriological and chemical (NBC) protection suites and for aerospace applications.

    The properties of the coated textiles were analyzed in terms of surface morphology, silver concentration and silver release in artificial sweat and synthetic tap water, respectively. No release of silver nanoparticles was observed at given conditions.

    The water repellency, permeability, flammability and mechanical resistance of the textiles before and after sputtering demonstrated that the textile properties were not negatively affected by the coating.

    The antibacterial effect was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus and compared with the behavior of uncoated textiles.

    The coating process conferred all textiles a good antibacterial activity. Optimal deposition conditions were elaborated to obtain sufficient antibacterial action without altering the aesthetical appearance of the textiles.

    The antibacterial coating retained its antibacterial activity after one cycle in a washing machine only for the Nylon based textile.

  • 622. Ferrero, B.
    et al.
    Boronat, T.
    Moriana, Rosana
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Fenollar, O.
    Balart, R.
    Green composites based on wheat gluten matrix and posidonia oceanica waste fibers as reinforcements2013In: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 34, no 10, p. 1663-1669Article in journal (Refereed)
    Abstract [en]

    In this work, green composites from renewable resources were manufactured and characterized. A fibrous material derived from Posidonia oceanica wastes with high cellulose content (close to 90 wt% of the total organic component) was used as reinforcing material. The polymeric matrix to bind the fibers was a protein (wheat gluten) type material. Composites were made by hot-press molding by varying the gluten content on composites in the 10-40 wt% range. Mechanical properties were evaluated by standardized flexural tests. Thermo-mechanical behavior of composites was evaluated with dynamic mechanical analysis (torsion DMA) and determination of heat deflection temperature. Morphology of samples was studied by scanning electronic microscopy and the water uptake in terms of the water submerged time was evaluated to determine the maximum water uptake of the fibers in the composites. Composites with 10-40 wt% gluten show interesting mechanical performance, similar or even higher to many commodity and technical plastics, such as polypropylene. Water resistance of these composites increases with the amount of gluten. Therefore, the sensitiveness to the water of the composites can be tailored with the amount of gluten in their formulation.

  • 623.
    Filip, Kvarnlöf
    KTH, School of Chemical Science and Engineering (CHE).
    Nya kompositfilmer genom sammanpressning av Layer-by-Layer modifierade aerogeler av nanocellulosa2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 624.
    Fillman, Benny
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    System studies of MCFC power plants2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    A fuel cell is an electrochemical reactor, directly converting chemically bound energy to electrical energy. In stationary power production the fuel cell stack itself is only a small component of the whole system. The integration of all the auxiliary components, the Balance-of-Plant (BoP), is one of the main issues in the study of fuel cell power plants.

    This thesis concerns the systems studies of molten carbonate fuel cell (MCFC) based power plants. The system studies has been performed with the simulation software Aspen PlusTM.

    Paper I describes on the implementation of a developed MCFC stack model into Aspen PlusTM in order to study an MCFC power plant fueled with natural gas.

    Paper II describes how different process parameters, such as fuel cell fuel utilization, influence the performance of an MCFC power plant.

  • 625.
    Fillman, Benny
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Björnbom, Pehr
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sylwan, Christopher
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sparr, Mari
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Influence of process parameters on the system efficiency of anatural gas or a gasified biomass fueled MCFC systemManuscript (preprint) (Other academic)
  • 626.
    Finne Wistrand, Anna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Polylactide:  2011In: Handbook of Engineering and Speciality Thermoplastics: Polyethers and Polyesters / [ed] S. Thomas and V. P.M., Hoboken, NJ, USA: John Wiley & Sons, 2011, p. 349-376Chapter in book (Other academic)
    Abstract [en]

    The production of durable functional products without using petroleumbased raw materials is a focus of much academic research today but it is also prioritized by many industries. Many questions still remain concerning the use, production and properties of bio-based and/or degradable polymers and whether or not they are more environmentally friendly than oil-based products. Polylactide is a bio-based compostable thermoplastic that is considered as one of the most promising materials for replacement of traditional volume plastics. The properties of polylactide can be tuned to resemble polystyrene, poly(ethylene terephthalate) or polyolefins by controlling the stereochemistry by copolymerization or blending. This chapter reviews the life-cycle of polylactide based materials as well as the properties and applications. The recent trends in the area are also discussed.

  • 627. Finnveden, G
    et al.
    Albertsson, A-C.
    Berendson, J.
    Eriksson, E.
    Höglund, L-O.
    Karlsson, S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Sundquist, J-O.
    Solid waste treatment within the framework of life-cycle assessment1995In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 3, p. 189-Article in journal (Refereed)
  • 628.
    Fischer, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Nordström, Fredrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    (2/1) p-Hydroxybenzoic acid-1,4-Dioxane SolvateManuscript (Other academic)
  • 629.
    Fjordefalk, Vera
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Reningsmetoder för dagvatten innehållande mikroplaster från konstgräsplaner2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The number of artificial turfs in Sweden has increased significantly since the year 2000. Today there are about 1255 outdoor pitches made from artificial turf and the annual increase is estimated at 100 pitches. Artificial turfs provide many benefits for sporting activities such as longer game seasons and more playing hours. To gain characteristics as close to natural turfs as possible, infill is used on top of the artificial grass. The infill is usually made out of styrene-butadien rubber (SBR), ethylene-propylene-diene-monomer-rubber (EPDM) or thermoplastic estalomer (TPE). However, there is also organic alternativs made from cork or coconut. Since the filling materials mostly consist of plastic polymers, some environmental concerns have been raised in the connection of the use of infill.

    The manufacturing size of infill is between 2-3 mm and is thereby classified as primary microplastics. The Swedish Environment Institute performed a study to map the sources of microplastic emissions to the marine environment. The study concluded that artificial turfs was the second largest land-based source of microplastic emission. The conclusion was based on the suggested annual amount for refill of infill for a full-size pitch. The amount of microplastics ending up in the sea, lakes and streams was not answered in the study, as it would require a more extensive mapping of routes. Former studies have shown that a certain amount of infill ends up in the stormwater wells which is placed around the turfs to prevent water collection.

    In order to prevent continued spreading via stormwater wells out to marine environments, treatment methods for stormwater runoff from artificial turfs has been requested.The objective of this study is to identify suitable methods for treatment of stormwater containing microplastics from artificial turfs. To find out what methods are used today, four manufacturers of granulate traps and filters were contacted. The municipalities that have installed or planned to install any of the stormwater treatment methods was also contacted to get an understanding of how these methods works in practice. From the study it is apparent that the development of treatment methods mentioned is in an early stage where efficiency is not tested for any of the methods. In order to determine what a suitable stormwater treatment method is in this case, further studies on how water flows vary between different pitch designs and surrounding surfaces are required. In this study the amount of microplastics found in the stormwater wells is solely based on ocular inspection and often described as "small" by the interviewees. To determine the exact amount of microplastics that can occur in stormwater wells, it would be necessary to weigh the microplastics found in the wells on every single plant. Because of differences in maintenance routines and depending on the existence of available surfaces for storage of snow and infill, the amount of microplastics found in the wells varies.

    The size of microplastics found was estimated to be of manufacturing size (2-3 mm). However, microplastics can become very small, down to 1 μm and hard to see with the naked eye. Further studies are recommended to set up a grain size distribution curve which can be used to manufacture the mesh in a reasonable size. The small sizes of microplastics makes it unreasonable to expect a purification degree f 100%, the mesh size would make it impossible for water to flow through. This calls for establishing guidance values for microplastics in stormwater.

    In order to establish guidance values and carry out necessary studies to develope the existing methods, a better cooperation between institution and trade and industry is needed. A method can be considered to be suitable for microplastics if the largest percentage part by weight of microplastics is caught. The suitability of the current methods cannot be judged until this is determined.

  • 630. Flamme, Michael
    et al.
    Milani, Ambrogio
    Wünning, Joachim
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Szewczyk, Dariusz
    Sudo, Jun
    Mochida, Susumu
    Radiant Tube Burners2010In: Industrial Combustion Testing / [ed] Charles E Baukal, Taylor & Francis Group, 2010, p. 487-504Chapter in book (Other academic)
  • 631. Flink, Johannes
    et al.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    The effects of lignin structure from treatment of pulp with activated 1-hydroxybenzotrazole.1997In: Proceedings 9th Int. Symp. Wood Pulp Chem., 1997Conference paper (Refereed)
  • 632.
    Flock, Sofia
    KTH, School of Chemical Science and Engineering (CHE).
    Comparison of enzymatic and refining treatment of pulp fibres for strength improvement2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, in pulp and paper industry, refining is used for strength improvement. This process requires energy and therefore, alternative methods with less energy consumption are of interest for the industry. In tissue production, only small energy consumption is used for refining and an enzymatic treatment could possibly replace the refining process. Therefore, a quantitative comparison between refining and enzymatic treated pulp as a function of grammage was done in this study. To find out if it was possible to replace refining by enzymes, a bleached kraft softwood pulp from pine and spruce was used. The pulp was subjected to enzymatic treatments of two different monocomponent endoglucanases and by mechanical treatment by a Voith laboratory refiner for comparison. To investigate different properties of the samples, tensile test, stretch at break and Schopper-Riegler was performed. The experiments in this study demonstrated that the enzymatic treatment did not give any effect on strength or dewatering. Therefore, enzymes cannot replace refining by the method used in this study.

  • 633.
    Fogelström, Linda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hansson, Susanne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Linear vs. Hyperbranched Polymers in the Preparation of Polymer/Clay NanocompositesManuscript (preprint) (Other academic)
  • 634.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Towards sustainable urban transportation: Test, demonstration and development of fuel cell and hybrid-electric buses2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Several aspects make today’s transport system non-sustainable:

    • Production, transport and combustion of fossil fuels lead to global and local environmental problems.

    • Oil dependency in the transport sector may lead to economical and political instability.

    • Air pollution, noise, congestion and land-use may jeopardise public health and quality of life, especially in urban areas.

    In a sustainable urban transport system most trips are made with public transport because high convenience and comfort makes travelling with public transport attractive. In terms of emissions, including noise, the vehicles are environmentally sustainable, locally as well as globally. Vehicles are energy-efficient and the primary energy stems from renewable sources. Costs are reasonable for all involved, from passengers, bus operators and transport authorities to vehicle manufacturers. The system is thus commercially viable on its own merits.

    This thesis presents the results from three projects involving different concept buses, all with different powertrains. The first two projects included technical evaluations, including tests, of two different fuel cell buses. The third project focussed on development of a series hybrid-bus with internal combustion engine intended for production around 2010. The research on the fuel cell buses included evaluations of the energy efficiency improvement potential using energy mapping and vehicle simulations. Attitudes to hydrogen fuel cell buses among passengers, bus drivers and bus operators were investigated. Safety aspects of hydrogen as a vehicle fuel were analysed and the use of hydrogen compared to electrical energy storage were also investigated.

    One main conclusion is that a city bus should be considered as one energy system, because auxiliaries contribute largely to the energy use. Focussing only on the powertrain is not sufficient. The importance of mitigating losses far down an energy conversion chain is emphasised. The Scania hybrid fuel cell bus showed the long-term potential of fuel cells, advanced auxiliaries and hybrid-electric powertrains, but technologies applied in that bus are not yet viable in terms of cost or robustness over the service life of a bus. Results from the EU-project CUTE show that hydrogen fuelled fuel cell buses are viable for real-life operation. Successful operation and public acceptance show that focus on robustness and cost in vehicle design were key success factors, despite the resulting poor fuel economy. Hybrid-electric powertrains are feasible in stop-and-go city operation. Fuel consumption can be reduced, comfort improved, noise lowered and the main power source downsized and operated less dynamically. The potential for design improvements due to flexible component packaging is implemented in the Scania hybrid concept bus. This bus and the framework for its hybrid management system are discussed in this thesis.

    The development of buses for a more sustainable urban transport should be made in small steps to secure technical and economical realism, which both are needed to guarantee commercialisation and volume of production. This is needed for alternative products to have a significant influence. Hybrid buses with internal combustion engines running on renewable fuel is tomorrow’s technology, which paves the way for plug-in hybrid, battery electric and fuel cell hybrid vehicles the day after tomorrow.

  • 635.
    Folkesson, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Andersson, Christian
    Lund Univ, Dept Ind Elect Engn & Automat.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alaküla, Mats
    Lund Univ, Dept Ind Elect Engn & Automat.
    Overgaard, Lars
    Bus Chassis Pre Dev Dept, Scania.
    Real life testing of a hybrid PEM fuel cell bus2003In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 118, no 1-2, p. 349-357Article in journal (Refereed)
    Abstract [en]

    Fuel cells produce low quantities of local emissions, if any, and are therefore one of the most promising alternatives to internal combustion engines as the main power source in future vehicles. It is likely that urban buses will be among the first commercial applications for fuel cells in vehicles. This is due to the fact that urban buses are highly visible for the public, they contribute significantly to air pollution in urban areas, they have small limitations in weight and volume and fuelling is handled via a centralised infrastructure.

    Results and experiences from real life measurements of energy flows in a Scania Hybrid PEM Fuel Cell Concept Bus are presented in this paper. The tests consist of measurements during several standard duty cycles. The efficiency of the fuel cell system and of the complete vehicle are presented and discussed. The net efficiency of the fuel cell system was approximately 40% and the fuel consumption of the concept bus is between 42 and 48% lower compared to a standard Scania bus. Energy recovery by regenerative braking saves up 28% energy. Bus subsystems such as the pneumatic system for door opening, suspension and brakes, the hydraulic power steering, the 24 V grid, the water pump and the cooling fans consume approximately 7% of the energy in the fuel input or 17% of the net power output from the fuel cell system.

    The bus was built by a number of companies in a project partly financed by the European Commission's Joule programme. The comprehensive testing is partly financed by the Swedish programme "Den Grona Bilen" (The Green Car). A 50 kW(el) fuel cell system is the power source and a high voltage battery pack works as an energy buffer and power booster. The fuel, compressed hydrogen, is stored in two high-pressure stainless steel vessels mounted on the roof of the bus. The bus has a series hybrid electric driveline with wheel hub motors with a maximum power of 100 kW.

    Hybrid Fuel Cell Buses have a big potential, but there are still many issues to consider prior to full-scale commercialisation of the technology. These are related to durability, lifetime, costs, vehicle and system optimisation and subsystem design. A very important factor is to implement an automotive design policy in the design and construction of all components, both in the propulsion system as well as in the subsystems.

  • 636.
    Folkesson, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Study of the fuel economy improvement potential of fuel cell buses by vehicle simulationArticle in journal (Other academic)
  • 637.
    Folkesson, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Neuman, Magnus
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Gravesen, Christian
    Scania, Bus Development.
    Targets, constraints and rules for hybrid management in a series hybrid bus intended for commercial introduction2008In: SAE Technical Papers, 2008, no 2008-01-1563Conference paper (Refereed)
  • 638. Fonseca, R. D.
    et al.
    Correa, D. S.
    Paris, E. C.
    Tribuzi, V.
    Dev, Apurba
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Voss, T.
    Aoki, P. H. B.
    Constantino, C. J. L.
    Mendonca, C. R.
    Fabrication of zinc oxide nanowires/polymer composites by two-photon polymerization2014In: Journal of Polymer Science Part B: Polymer Physics, ISSN 0887-6266, E-ISSN 1099-0488, Vol. 52, no 4, p. 333-337Article in journal (Refereed)
    Abstract [en]

    We present an approach to fabricate ZnO nanowires/polymer composite into three-dimensional microstructures, based on two-photon polymerization direct laser writing, a fabrication method that allows submicrometric spatial resolution. The structural integrity of the structures was inferred by scanning electron microscopy, while the presence and distribution of ZnO nanowires was investigated by energy dispersive X-ray, Raman spectroscopy, and X-ray diffraction. The optical properties of the produced composite microstructures were verified by imaging the characteristic ZnO emission using a fluorescence microscope. Hence, such approach can be used to develop composite microstructures containing ZnO nanowires aiming at technological applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 333-337 Zinc oxide (ZnO) has proven to be a promising material for optoelectronic devices operating in the blue to near-UV spectral region. While ZnO/polymer composite films have been readily produced via cast and spin coating, these standard approaches do not allow the fabrication of three-dimensional (3D) microstructures due to the lack of spatial resolution. In this work, 3D microstructures of composites made up of acrylic resin and ZnO nanowires are created by using two-photon polymerization.

  • 639.
    Forcyde, Ness
    KTH, School of Chemical Science and Engineering (CHE).
    Removal of Residual Monomers from Polymer Suspensions2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the challenges with suspension polymerization is the removal of residual monomers. Environmental regulations and market preferences are the main driving forces behind the development of novel methods and improvement of current methods. In this work, the removal of monomers has been studied using two types of chemistries: post-polymerization with radical initiators, and aza-Michael addition. Two radical initiators with different degrees of hydrophobicity were used to polymerize residual monomers in polymer particle dispersions. Results show that both initiators succeeded in removing residual monomers, but the hydrophilic initiator is more efficient than the hydrophobic initiator. Two different substrates have been amine-functionalized and reacted with methyl acrylate (monomer) in water. The functionalized substrates were characterized using Kaiser test and UV/Vis spectroscopy. The heterogeneous nature of one of the substrates seems to affect the reproducibility of the analysis results. Data suggest that the amine-functionalized substrates react with methyl acrylate at 60 °C in water and full conversion may be achieved using stoichiometric ratios. However, the amount of results was limited and more experiments are needed.

  • 640.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of Metal Fluoride Hydrates from Mixed Acid Solutions2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this work crystal growth and nucleation of b-FeF3×3H2O and crystallization of chromium (III), iron (III) and nickel (II) fluoride hydrates from mixed acid (1-3 mol/kg HNO3 and 1-6 mol/kg free HF) have been investigated.

    The solubility of b-FeF3×3H2O has been determined in solutions of different hydrofluoric acid (1-7mol/ kg) and nitric acid (0-7mol/ kg) concentrations at 30, 40 and 50°C. The total iron concentration at equilibrium ranges from about 1 to 35 g/kg solution. In the range of investigated conditions the solubility in terms of total iron content increases with increasing temperature and decreases with increasing concentration of hydrofluoric acid and nitric acid. The results are analysed by examining the chemical speciation in the solutions.

    The crystal growth kinetics of b-FeF3×3H2O crystals have been studied by performing seeded isothermal desupersaturation experiments in solutions of 1.5-3.0 mol/ kg nitric acid and 1.4- 5.6 mol/ kg free hydrofluoric acid at 30, 40 and 50°C. The results show that the crystal growth is surface integration controlled. When the driving force is based on a proper speciation no clear correlation of the growth rate with hydrofluoric acid or nitric acid concentration is found. The rate is about the same in industrial pickle liquor as in pure acid solutions. The growth rate at a supersaturation ratio (c(FeF3)free/cs(FeF3)free) of 2 was found to be 5.2×10-12m/s at 30°C, 7.9×10-12m/s at 40°C and 20×10-12m/s at 50°C. Thus, the crystal growth rate at 50°C is about four times higher than at 30°C. The temperature dependence of the rate constant corresponds to an activation energy of 55kJ/ mol.

    Crystallization from solutions supersaturated with both Cr(III) and Fe(III) has been investigated and it has been observed that Fe(III) and Cr(III) crystallizes in the form of Cr(Fe)F3×3H2O which is isostructural with CrF3×3H2O. Iron(III) and nickel(II) crystallizes into an unidentified fluoride hydrate crystal.

    The crystal growth rate of CrF3×3H2O at 50°C is about the same as the growth rate of b-FeF3×3H2O crystals.

  • 641.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Valorisation of phosphate rock by hydrometallurgical processing2017In: 16ème Congrès de la Société Française de Génie des Procédés SFGP (16th Congress of the French Chemical Engineering Society), 2017Conference paper (Refereed)
  • 642.
    Forsberg, Kerstin M.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mohammadi, M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ghafarnejad Parto, S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Martínez de la Cruz, Joaquin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Fredriksson, A.
    LKAB.
    Recovery of REE from an apatite concentrate2014Conference paper (Refereed)
  • 643.
    Forsberg, Kerstin M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    The influence of hydrofluoric acid and nitric acid on the growth kinetics of iron(III) fluoride trihydrate2015In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 423, p. 16-21Article in journal (Refereed)
    Abstract [en]

    The influence of hydrofluoric acid and nitric acid concentration on the growth rate of beta-FeF3 center dot 3H(2)O crystals has been studied in different hydrofluoric acid (4.7-10.7 mol/(kg H2O)) and nitric acid (2.1-4.6 mol/(kg H2O)) mixtures at 50 degrees C. Seeded desupersaturation experiments were performed and the results were evaluated by considering the chemical speciation using two different speciation programs. The growth rate at 50 degrees C at a supersaturation ratio of 2, expressed in terms of free FeF3, was found to be in the range of (0.4-3.8) x 10(-11) m/s. The growth rate order was found to be two or higher in all experiments. The low growth rate and high growth rate order indicate that the growth rate is governed by the surface integration step. The growth rate was found to be independent of variations in acid concentrations: this is in accordance with the assumption of a surface integration controlled growth rate.

  • 644.
    Forsberg, Kerstin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mohammadi, M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ghafarnejad Parto, S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Alemrajabi, Mahmoud
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Korkmaz, Kivanc
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Martínez De La Cruz, Joaquin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Novel hydrometallurgical methods for recovery and separation of REE2014Conference paper (Refereed)
  • 645.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystal growth of iron(III) flouride trihydrate in mixed acidManuscript (preprint) (Other academic)
  • 646.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization in hydrofluoric acid and nitric acid solutions containing iron(III), chronium(III) and nickel(II).Manuscript (preprint) (Other academic)
  • 647.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of metal fluoride hydrates from mixed hydrofluoric and nitric acid solutions, Part I: Iron (III) and Chromium (III)2010In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 312, no 16-17, p. 2351-2357Article in journal (Refereed)
    Abstract [en]

    Crystallization from hydrofluoric acid/nitric acid solutions supersaturated with Fe(III) and Cr(III) has been investigated. Iron and chromium crystallizes into a solid solution in the form of Cr(Fe)F-3 center dot 3H(2)O, which is isostructural with CrF3 center dot 3H(2)O and alpha-FeF3 center dot 3H(2)O. By seeded isothermal desupersaturation experiments, the growth rate of beta-FeF3 center dot 3H(2)O crystals at 50 degrees C has been studied in hydrofluoric acid and nitric acid solutions containing Cr(III). It is found that the growth rate of beta-FeF3 center dot 3H(2)O is essentially uninfluenced by the presence of 5 g/kg Cr(III). At 50 degrees C and a supersaturation ratio of 2 (c(FeF3)(free)/c(s)(FeF3)(free)), the growth rate is (0.8-2.2) x 10(-11) m/s in 3 mol/(kg solution) HFfree and 3 mol/(kg solution) HNO3.

  • 648.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of metal fluoride hydrates from mixed hydrofluoric and nitric acid solutions, part II: Iron (III) and nickel (II)2010In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 312, no 16-17, p. 2358-2362Article in journal (Refereed)
    Abstract [en]

    Crystallization of nickel fluoride hydrate from mixed pickle acid and the influence of Ni(II) on growth rate of beta-FeF3 center dot 3H(2)O have been studied. Iron and nickel crystallize into an unidentified Fe/Ni fluoride hydrate crystal having the overall mol ratio of Ni, Fe, and F equal to 1:2:8, which is in accordance with the number of fluoride ions needed to balance the positive charges of Ni and Fe. The most probable empirical formula of this material is (FeF3)(2)NiF2(H2O)(6-10). By seeded isothermal desupersaturation experiments, growth rate of beta-FeF3 center dot 3H(2)O crystals at 50 degrees C has been studied in a hydrofluoric acid and nitric acid solution containing Ni(II). It is found that the growth rate of beta-FeF3 center dot 3H(2)O is essentially uninfluenced by the presence of 4 g/kg Ni(II).

  • 649.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystal growth kinetics of iron fluoride trihydrate2006In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 296, no 2, p. 213-220Article in journal (Refereed)
    Abstract [en]

    Crystal growth of beta-FeF3 • 3H(2)O has been investigated in mixtures of 3 mol kg(-1) hydrofluoric acid and 3 mol kg(-1) nitric acid at 30, 40 and 50 degrees C. Seeded isothermal desupersaturation experiments have been performed in the range: 1.3 < S < 3.6. Solution samples were analysed for total iron concentration with inductively coupled plasma atomic emission spectroscopy. The true supersaturation driving force was estimated by a proper speciation using the software SSPEC using appropriate stability constants. Growth rate parameters of the BCF surface diffusion growth rate equation and the empirical power-law equation have been estimated by fitting the supersaturation balance equation using a nonlinear optimization procedure. The results show that the growth rate is surface integration controlled. The growth rate at a supersaturation ratio of 2 was found to be 3.5 x 10(-12) m s(-1) at 30 degrees C, 7.4 x 10(-12) m s(-1) at 40 degrees C and 16 x 10(-12) m s(-1) at 50 degrees C. The activation energy of the rate constant of crystal growth was found to be 61 kJ mol(-1). .

  • 650.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Recycling of waste pickle acid by precipitation of metal fluoride hydrates2007In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 20, no 9, p. 950-955Article in journal (Refereed)
    Abstract [en]

    Stainless steel is pickled in mixed acid solutions (1-3 M HNO3 and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of beta-FeF3 . 3H(2)O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of beta-FeF3 . 3H(2)O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of beta-FeF3 . 3H(2)O has been determined in industrial pickle bath solutions at 50 degrees C and the results have been compared to previous measurements in pure HF/HNO3 solutions prepared in the laboratory. The growth rate of beta-beta eF(3) . 3H(2)O crystals at 50 degrees C is in the order of 10(-11) m/s in both industrial and pure acid mixtures.

10111213141516 601 - 650 of 2463
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