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  • 451. Dau, H.
    et al.
    Fujita, E.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Artificial Photosynthesis: Beyond Mimicking Nature2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4228-4235Article in journal (Refereed)
    Abstract [en]

    In this Editorial, Guest Editors Holger Dau, Etsuko Fujita, and Licheng Sun introduce the Special Issue of ChemSusChem on “Artificial Photosynthesis for Sustainable Fuels”. They discuss the need for non-fossil based fuels, introduce both biological and artificial photosynthesis, and outline various important concepts in artificial photosynthesis, including molecular and solid-state catalysts for water oxidation and hydrogen evolution, catalytic CO2 reduction, and photoelectrochemical systems.

  • 452. Dax, Daniel
    et al.
    Soledad Chavez, Maria
    Xu, Chunlin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Process Chemistry Centre, C/o Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Finland .
    Willfor, Stefan
    Teixeira Mendonca, Regis
    Sanchez, Julio
    Cationic hemicellulose-based hydrogels for arsenic and chromium removal from aqueous solutions2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 111, p. 797-805Article in journal (Refereed)
    Abstract [en]

    In this work the synthesis of hemicellulose-based hydrogels and their application for the removal of arsenic and chromium ions is described. In a first step O-acetyl galactoglucomannan (GGM) was subjected to a transesterification applying glycidyl methacrylate (GMA) for the synthesis of novel GGM macromonomers. Two distinguished and purified GGM fractions with molar mass of 7.1 and 28 kDa were used as starting materials. The resulting GGM macromonomers (GGM-MA) contained well-defined amounts of methacrylate groups as determined by H-1 NMR spectroscopy. Selected GGM-MA derivatives were consecutively applied as a crosslinker in the synthesis of tailored hydrogels using [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) as monomer. The swelling rate of the hydrogels was determined and the coherence between the swelling rate and the hydrogel composition was examined. The morphology of the GGM-based hydrogels was analysed by SEM and the hydrogels revealed a high surface area and were assessed in respect to their ability to remove arsenate and chromate ions from aqueous solutions. The presented bio-based hydrogels are of high interest especially for the mining industries as a sustainable material for the treatment of their highly contaminated wastewaters.

  • 453.
    de Carvalho, Danila Morais
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Federal University of Viçosa, Brazil.
    Colodette, Jorge Luiz
    Comparative Study of Acid Hydrolysis of Lignin and Polysaccharides in Biomasses2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 4, p. 6907-6923Article in journal (Refereed)
    Abstract [en]

    Effects of different acid hydrolysis conditions were studied relative to the chemical transformations of lignin in eucalyptus, sugarcane bagasse, and sugarcane straw, and on the transformations of multiple polysaccharides in eucalyptus. The acid hydrolysis using 12 mol/L sulfuric acid followed by acid hydrolysis using approximately 0.41 mol/L sulfuric acid was used as the reference for the lignin and sugar analysis. During acid hydrolysis, the relative amount of lignin increased with longer reaction times and/or greater acid concentrations for all biomasses. The overestimation of lignin in harsher acidic conditions resulted from the summation of lignocellulosic-derivatives (pseudo- lignin) together with lignin itself. Lignin reactions (dissolution/deposition) for bagasse and straw occurred in a greater extent than for eucalyptus, considering similar conditions of acid hydrolysis. The sugar transformation during acid hydrolysis was also investigated for eucalyptus. The sugar content quantified in eucalyptus decreased as the acid concentration and/or reaction time in the second hydrolysis increased. Glucose, galactose, and mannose were more resistant to harsher acidic conditions than xylose and arabinose. However, the most severe conditions (121 degrees C, 90 min, and 6.15 mol/L H2SO4) caused complete sugar degradation.

  • 454.
    Decrop, Deborah
    et al.
    KU Leuven, Belgium.
    Pardon, Gaspard
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Kokalj, Tadej
    KU Leuven, Belgium.
    Robert, Puers
    KU Leuven, Belgium.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Lammertyn, Jeroen
    KU Leuven, Belgium.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Single-step manufacturing of femtoliter microwell arrays in a novel surface energy mimicking polymer2015In: 18th International Conference on Solid-State Sensors, Actuators and Microsystems (IEEE TRANSDUCER 2015), IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    We report a novel polymer material formulation and stamp-molding technique that enable rapid single-step manufacturing of hydrophilic-in-hydrophobic microwell arrays. We developed a modified thiol-ene-epoxy polymer (mOSTE+) formulation that mimics the surface energy of its mold during polymerization. The polymer inherits the surface energy from the mold through molecular self-assembly, in which functional monomers self-assemble at the interface between the liquid prepolymer and the mold surface. Combining this novel mOSTE+ material with a stamp-molding process leads to simultaneous surface energy mimicking and micro-structuring. This method was used to manufacture microwells with hydrophilic bottom and hydrophobic sidewall, depressed in a surrounding hydrophobic surface. The microwell arrays were successfully tested for the self-assembly of 62’000 femtoliter-droplets. Such femtoliter droplet arrays are useful for, e.g., digital ELISA and single cell/molecule analysis applications.

  • 455.
    Dedic, Dina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Iversen, Tommy
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Cellulose degradation in the Vasa: The role of acids and rust2013In: Studies in Conservation, ISSN 0039-3630, E-ISSN 2047-0584, Vol. 58, no 4, p. 308-313Article in journal (Refereed)
    Abstract [en]

    The oak timbers of the Swedish warship Vasa are deteriorating. High amounts of oxalic acid have been found along with a low pH and low molecular weight cellulose deep in the wood timbers. The iron-rich surface wood differs from the interior wood in that it displays higher pH and cellulose with higher molecular weight. The objective of this study was to determine why there is a difference in cellulose degradation, pH, and oxalic acid amount between the surface region and the interior of the Vasa timbers. Analysis of cellulose weight average molecular weight by size exclusion chromatography was performed, as well as quantification of oxalic acid and iron by high-performance anion exchange chromatography and atomic emission spectroscopy, respectively. It was found that a decrease in iron content coincides with an increase in oxalic acid concentration and a drop in pH at a certain depth from the wood surface. When iron-rich surface wood samples from the Vasa were mixed with an aqueous solution of oxalic acid, a fast increase of pH over time was observed. Neither interior wood poor in iron nor the fresh oak reference showed the same neutralizing effect during the time of measurement. This indicates that the presence of iron (rust) causes a neutralization of the wood, through the formation of iron(III) oxalato complexes, thus protecting the wood from oxalic acid hydrolysis. This effect was not observed to the same extent for other acids observed in Vasa wood (sulfuric, formic, glycolic, and acetic acids).

  • 456.
    Dedic, Dina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Iversen, Tommy
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Degradation reactions in vasa wood2011In: Shipwrecks 2011, 2011, p. 114-116Conference paper (Refereed)
  • 457.
    Dedic, Dina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Iversen, Tommy
    Sandberg, Teresia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Chemical analysis of wood extractives and lignin in the oak wood of the 380 year old Swedish warship Vasa2011Conference paper (Refereed)
    Abstract [en]

    In order to map the source of oxalic acid in the interior wood of the Vasa ship, an analysis of wood extractives (tannins) was conducted. Samples used for analysis were PEG-impregnated dry Vasa wood, waterlogged Vasa wood and a reference material (fresh oak). The wood material was ground and extracted with an acetone/water-mixture. In the reference sample, several types of tannins were found such as the isomers castalagin/vescalagin and grandinin and their dimmers roburin A/D and roburin B/C respectively. The results have been confirmed by NMR spectroscopy and MALDI-TOF. The interior of the waterlogged Vasa wood contained small amounts of monomers, whereas the dry, PEG treated Vasa revealed no discernible amounts of hydrolysable tannins or other easily soluble compounds. Furthermore, an analysis of lignin was made by means of chemical degradation (thioacidolysis). A decrease in the amount of β-O-4 bonds in the lignin structure would imply a formation of easily oxidized free phenolics. The products were analyzed by GC-MS, which revealed no dramatic differences between the Vasa samples and the reference. The results were confirmed by CP/MAS NMR by analyzing the differences in the aromatic region (150∼160 ppm) as well as the carbonyl region (190∼200 ppm).

  • 458.
    Dedic, Dina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Sandberg, Teresia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Iversen, Tommy
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Larsson, Tomas
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Analysisof lignin and extractives in the oak wood of the 17th century warship Vasa2011Manuscript (preprint) (Other (popular science, discussion, etc.))
  • 459.
    Degerman Engfeldt, Johnny
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Predicting Electrochromic Smart Window Performance2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The building sector is one of the largest consumers of energy, where the cooling of buildings accounts for a large portion of the total energy consumption.

    Electrochromic (EC) smart windows have a great potential for increasing indoor comfort and saving large amounts of energy for buildings. An EC device can be viewed as a thin-film electrical battery whose charging state is manifested in optical absorption, i.e. the optical absorption increases with increased state-of-charge (SOC) and decreases with decreased state-of-charge. It is the EC technology's unique ability to control the absorption (transmittance) of solar energy and visible light in windows with small energy effort that can reduce buildings' cooling needs.

    Today, the EC technology is used to produce small windows and car rearview mirrors, and to reach the construction market it is crucial to be able to produce large area EC devices with satisfactory performance. A challenge with up-scaling is to design the EC device system with a rapid and uniform coloration (charging) and bleaching (discharging). In addition, up-scaling the EC technology is a large economic risk due to its expensive production equipment, thus making the choice of EC material and system extremely critical. Although this is a well-known issue, little work has been done to address and solve these problems.

    This thesis introduces a cost-efficient methodology, validated with experimental data, capable of predicting and optimizing EC device systems' performance in large area applications, such as EC smart windows. This methodology consists of an experimental set-up, experimental procedures and a twodimensional current distribution model. The experimental set-up, based on camera vision, is used in performing experimental procedures to develop and validate the model and methodology. The two-dimensional current distribution model takes secondary current distribution with charge transfer resistance, ohmic and time-dependent effects into account. Model simulations are done by numerically solving the model's differential equations using a finite element method. The methodology is validated with large area experiments.

    To show the advantage of using a well-functioning current distribution model as a design tool, some EC window size coloration and bleaching predictions are also included. These predictions show that the transparent conductor resistance greatly affects the performance of EC smart windows.

  • 460.
    Della Vedova, Luca
    KTH, School of Chemical Science and Engineering (CHE).
    Development of a Minimally Invasive Oxygen Measurement Catheter for Brain Monitoring Applications2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 461.
    Deng, Tengfei
    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.
    Study of Lime Dissolution Under Forced Convection2012In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 43, no 3, p. 578-586Article in journal (Refereed)
    Abstract [en]

    Dissolution of different CaO cubes under force convection in liquid CaO-"FeO"-SiO2 slag was studied at 1873 K (1600 A degrees C). A linear relationship between normalized lengths and time was obtained after the experiment. It was evidently observed that the removal of the interface layer(s) including 2CaO center dot SiO2 by shear stress was the main mechanism for the dissolution. A stirring rate of approximately 100 rpm was found to be efficient to remove the interface layer(s). The limes with different structures had different dissolution rates.

  • 462. Di Filippo, Maria
    et al.
    Alessi, Sabina
    Pitarresi, Giuseppe
    Sabatino, Maria Antonietta
    Zucchelli, Andrea
    Dispenza, Clelia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Univ Palermo, Italy.
    Hydrothermal aging of carbon reinforced epoxy laminates with nanofibrous mats as toughening interlayers2016In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 126, p. 188-195Article in journal (Refereed)
    Abstract [en]

    Electrospun mats have been applied as toughening interlayers in high performance carbon fiber epoxy composites. While the toughening mechanism exerted by the mat at the interface is the subject of several recent studies, no investigations are reported on the aging behaviour of laminates comprising these nanostructured elements. This work investigates the influence of the combined effect of water and temperature (90 degrees C) on laminates with Nylon 6,6 electrospun membranes placed either at the middle plane only or at each interlayer. The water-uptake behaviour is modelled by a two-stage diffusion model and compared with the behaviour of the neat resin and of the laminate without mats. Interestingly, a lower water uptake is observed for the laminates with mat-modified interfaces and this is possibly due to a significantly reduced porosity. The effect of hydrothermal aging on the thermal (Tg) and mechanical properties (transverse flexural modulus and interlaminar shear strength) of the various laminates is also investigated.

  • 463.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Tris(hydroxymethyl)aminomethane as a probe in heterogeneous TiO 2 photocatalysis2012In: Journal of AOTS. Advanced Oxidation Technologies, ISSN 1203-8407, Vol. 15, no 2, p. 392-398Article in journal (Refereed)
    Abstract [en]

    In this work we present a new route to probe the efficiency of aqueous TiO 2 photocatalysis using Tris(hydroxymethyl)aminomethane (Tris). Hydrogen abstracting species such as hydroxyl radicals react with Tris through hydrogen abstraction, which leads to the formation of formaldehyde. Formaldehyde was subsequently detected and quantified spectrophotometrically at 368 nm using a modified version of the Hantzsch reaction. The effect of Tris concentration on the photocatalytic production of formaldehyde was studied in the range 0.1-500 mM Tris. A strong concentration dependence was observed below 100 mM, which indicates that not all photo-produced (hydroxyl) radicals are scavenged at Tris concentrations below 100 mM. Therefore, in order to assess the maximum efficiency of the photocatalytic system, Tris concentrations above 100 mM are required. To evaluate the effect of O 2 on the formaldehyde yield in the reaction between Tris and the hydroxyl radical, a gamma radiolysis study was performed where Tris solutions saturated with O 2 and N 2, respectively, were irradiated in parallel and the yield of formaldehyde was compared. These results showed that O2 does not influence the formaldehyde yield.

  • 464.
    Dinko, Lukes
    KTH, School of Chemical Science and Engineering (CHE).
    Quantification of acid diffusion in fluoroplastic materials2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To improve the service reliability of polymeric materials used in corrosive environments more corrosion data such as diffusion of acids is needed. The aim of this research was to investigate the diffusion of acids mainly in fluoroplastic materials by optimizing quantitative and qualitative methods to measure the diffusion. It was found that ion chromatography could be used to measure the acid concentration found inside the different polymers by desorption into a water solution. The amount of ions was then recalculated and presented as gacid/gpolymer. The polymeric materials were exposed in hydrochloric acid, nitric acid, hydrobromic acid and mixed acid. Very large spreading was seen within each series for the polymers in the different acids resulting in very high standard deviations on the concentrations of acids. The cause of the spreading was not found,  but analyses on the acid concentration using inductively coupled plasma (ICP) verified the large spreading seen from the ion chromatograph and conclusions were drawn that the ion chromatography did not cause the spreading. Changes to the experimental procedure were made but did not resolve the problem. The solubility of hydrogen chloride was measured in the fluoropolymers: perfluoroalkoxy (PFA), polyvinylidene fluoride (PVDF) and ethylene-chlorotrifluoroethylene (ECTFE) and compared to the polyolefins: polyethylene (PE) and polypropylene (PP). It was found that the polyolefins had the highest solubility of hydrogen chloride and ECTFE had the lowest. Chlorine dioxide solubility in PVDF was established through a different approach, the LGB-method, but the problem with spreading was seen on these results as well. An indicator technique was used to calculate diffusion rates of HCl in polypropylene samples with successful results. However, the indicator technique did not work for the ECTFE samples.

  • 465.
    Djahed, Cyrus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Molecular scale deformation mechanisms in cellulose crystals (I and II) by molecular dynamics - synergy between covalent and hydrogen bondsManuscript (preprint) (Other academic)
  • 466.
    Djahedi, Cyrus
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. Wallenberg Wood Science Center.
    Deformation of cellulose allomorphs studied by molecular dynamics2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cellulose-based materials draw their good mechanical properties from the cellu-lose crystal. Improved understanding of crystal properties could lead to a wider range of applications for cellulose-based materials, Cellulose crystals show high axial Youngs modulus. Cellulose can attain several allomorphic forms which show unique structural arrangements in terms of both intra-molecular and inter-molecular bonding, as well as unit cell parameters and chain packing. Although several studies have confirmed that mechanical tensile properties of cellulose differ between different allomorphic forms, few reports have investigated the deformation mechanisms explaining the differences.In the first part of this thesis, the tensile elastic Youngs modulus of cellulose allo-morphs Iβ, II and III I were calculated under uniform conditions using Molecular Dynamics simulation techniques. As expected, a difference in modulus valuesc ould be observed, and the cooperative nature of energy contributions to crys-tal modulus is apparent. The allomorphs also show large differences in terms of how contributions to elastic energy are distributed between covalent bonds,angles, dihedrals, electrostatic forces, dispersion and steric forces.In the second part of this thesis, the cellulose Iβ and II allomorphs were sub-jected to a more detailed structural study. The purpose was to clarify how the deformation of the central glucosidic linkage between the monomer units depends on the hydrogen-bonding structures. This was carried out by studying simulated vibrational spectra and local deformations in the crystals.The results presented in this thesis confirm the differences in the tensile elastic properties of these cellulose allomorphs. These differences can in part be explained by the different intra-molecular hydrogen bonding patterns between allomorphs. Deformation mechanisms are discussed. The results are in supportof the so called ”leverage effect” proposed in the literature. The present analysis shows significant differences in details of deformation mechanisms compared with previous simpler analyses.

  • 467. Djahedi, Cyrus
    et al.
    Bergenstrahle-Wohlert, Malin
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Role of hydrogen bonding in cellulose deformation: the leverage effect analyzed by molecular modeling2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 4, p. 2315-2323Article in journal (Refereed)
  • 468.
    Djahedi, Cyrus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wohlert, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Molecular deformation mechanisms in cellulose allomorphs and the role of hydrogen bondsManuscript (preprint) (Other academic)
  • 469.
    Done, Victoria
    KTH, School of Chemical Science and Engineering (CHE).
    General description of measures for environmental compliance of substations owned by Svenska kraftnät in protected areas with focus on oil spill2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Svenska kraftnät is the Swedish transmission system operator, responsible for the national electrical grid with power lines of 220 kV and 400 kV, and the electrical substations of the grid. In this master thesis an old substation located in a sensitive environmental area is inspected and its environmental risks defined and assessed. From this “worst case scenario” measures are recommended, that should be applicable on other existing substations, and for new constructed substations. This thesis is limited to a more detailed analysis on how oil spill can be handled. The insulating oil is used in different machines and equipment on the substation to avoid electrical charges.

    The inspected substation has a special feature; a pipe system that connects wells on the substation area, water pipes from the substation house, and transformer pits to an oil-water separation house. The oil pits are made of concrete and placed under machines with large amounts of oil to capture the oil in case of a breakdown or leakage. In the oil-water separation house oil is separated from water and the clean water is sent to a lake in the vicinity. The most severe environmental risks found are the filter in the oil-water separation house and the risk of oil leakage from the open water-cooling system of the synchronous generator. In addition, there is no way to catch oil spill from current and voltage transformers and it is not known if the pipe system that transports water and oil spills is completely sealed. Finally, there is no permanent installation to catch spills from tank filling areas and Svenska kraftnät does rarely follow up the environmental work of the entrepreneurs.

    Svenska kraftnät is recommended to use the products and services from the companies Qlean Scandinavia AB and TTL Miljöteknik AB to attend to the noted environmental risks. Qlean Scandinavia AB offers an environmental friendly cleaning procedure with ultraclean water and sealing of concrete, which can be used for the transformer pits and oil-water separation house. They also sell profile planks as a fire-extinguishing layer for transformer pits. These are considered better and safer than the conventional stones used. The price is almost the same, however the maintenance costs are lower for the profile planks, since they are easier to clean and do not require heavy transports to landfill. They also require less space than the stones, therefore a smaller transformer pit can be built, and cost savings can be made on concrete.

    TTL Miljöteknik AB has products based on environmental friendly oil solidifying polymers placed in different textiles and filters. They let water and other substances pass, but react with hydrocarbons, like oil, forming a tight rubberlike mass. These installations are new to Europe, but more than 12 000 installations have been made, mainly in the United States and Australia. For the inspected substation in this thesis it is recommended to manage oil spill at each machine and to clean the pipe system. An HFF-filter should be installed in cleaned and sealed transformer pits. The filter lets water from precipitation pass, but binds oil, thanks to the solidifying polymers. The clean water is further transported through the pipe system to the oil-water separation house and from there water is pumped to the lake. Wells must be sealed and the pipes from the substation house led to a septic tank. Agent X, a type of filter mat, should be placed on the substation area to catch oil spills from current and voltage transformers, since previous breakdowns show that oil can be spread over a large area.

    For plants without a pipe system the water will be released outside the transformer pits. For new constructions it is suggested that transformer pits are built with a polyvinyl mat in the bottom and a filter on the sides, which will capture the oil. A concrete fundament still needs to be built to support the machine; therefore the price will almost be the same as for the conventional transformer pit in concrete, although less concrete is needed. However, with this technique the transformer pit will not require any maintenance.

  • 470.
    Dong, Qian
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Transport in Oxides Studied by Gas Phase Analysis2007Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    The transport in oxides is studied by the use of gas phase analysis (GPA). An experimental method to identify transported species of gases and their contribution to the overall transport of gases in oxides and an experimental method to evaluate the parameters diffusivity, concentration, permeability of gases in oxides and effective pore size in oxides are developed, respectively.

    Pt has two effects on the thermal oxidation of metals. One is to enhance the oxidation of metals which takes place at the oxide-metal interface by promoting a high concentration gradient of dissociated oxygen across the oxide layer. The other effect is to suppress the oxidation of metals by decreasing the contact area between metal and oxygen. The overall effect of Pt on the oxidation of metals depends on the mechanism of oxide growth in the absence of Pt. It is suggested that an appropriate amount of Pt coating induces a balanced oxide growth resulting from stoichimetrical inward oxygen flux to outward metal flux, which leads to a reduced oxidation rate.

    The diffusion of diatomic gases in oxides such as vitreous silica and yttria stabilized zirconia (YSZ) takes place in both molecular and dissociated (atomic or/and ionic) form. The fraction of transport of molecular species decreases with temperatures, and the fraction of transport of dissociated species increases with temperatures. Measured permeabilities of diatomic gases in vitreous silica are higher than the expected permeabilities of their molecules, which are explained by diffusion of molecules combined with a retardation of dissociated species in reversible traps. The diffusion of hydrogen in vitreous silica is concentration dependent and increases with local concentration. Transport paths are shared among transported species and gases at all temperatures in YSZ. Helium shares transport path with molecular oxygen and nitrogen at low temperatures; whereas helium shares transport path with dissociated oxygen and also dissociated nitrogen at high temperatures.

  • 471.
    Dong, Qian
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Transport of gases in yttria-stabilized zirconia2007Article in journal (Other academic)
  • 472.
    Dong, Qian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Tang, Qing
    Li, Wenchao
    Al2O3-TiC-ZrO2 nanocomposites fabricated by combustion synthesis followed by hot pressing2008In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 475, no 1-2, p. 68-75Article in journal (Refereed)
    Abstract [en]

    Al2O3-TiC-ZrO2 nanocomposites were prepared by combustion synthesis followed by hot pressing with TiO2, Al, C and ZrO2 as raw materials. Combustion synthesis is favorable to obtain in situ formed powder with TiC and ZrO2 nanoparticles distributed in Al2O3 matrix. The effects of varying amount of ZrO2 nano-scale additives on the mechanical properties and microstructure of Al2O3-TiC composite were studied. An appropriate amount of ZrO2 nanoparticle additive improves the mechanical properties. The flexural strength and fracture toughness of Al2O3-TiC-10 wt.% ZrO2 composite were approximately 20% higher than that of Al2O3-TiC composite. The addition of ZrO2 nanoparticles reduced the grain size and improved the distribution of different phases. With the ZrO2 addition, the fracture mode changes from intergranular to mixed inter/transgranular fracture. The residual stresses are generated by the thermal expansion coefficient mismatch between different phases, which leads to the generation of dislocations and microcracks around the nanoparticles. The effects of nanoparticles on the deflected propagation, nailing and blocking of the dislocation and microcracks are believed to contribute to the improvement of the strength and toughness of Al2O3-TiC-ZrO2 composite.

  • 473.
    Du, Jian
    et al.
    Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China..
    Li, Fei
    Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China..
    Wang, Yong
    Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China..
    Zhu, Yong
    Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China..
    Cu3P/CuO Core-Shell Nanorod Arrays as High-Performance Electrocatalysts for Water Oxidation2018In: Chemelectrochem, ISSN 2196-0216, Vol. 5, no 15, p. 2064-2068Article in journal (Refereed)
    Abstract [en]

    Earth-abundant transition-metal-based oxides are potential candidates to replace the state-of-the-art noble-metal-based oxygen evolution catalysts (OECs) such as IrO2 and RuO2. Despite the low cost and large abundance, copper-based OER catalysts have been less frequently studied, mainly owing to the low electrical conductivity of copper oxides that results in large overpotential and sluggish kinetics for oxygen evolution. We report here the insitu fabrication of semi-metallic Cu3P nanorod arrays on commercial copper foam via a template approach; the resulting self-supported core-shell Cu-Cu3P/CuO electrode has the merits of high electrical conductivity, large active area, and short diffusion paths for electrolyte and evolved oxygen, exhibiting a low overpotential of 315mV and high durability over 50h at a current density of 10mAcm(-2) for OER in 1.0 M KOH. The remarkable OER performance reported here is not only superior to that of analogous Cu-CuO foam electrode, but also outperforms those of copper-based OER electrocatalysts in the literature.

  • 474.
    Du, Xueyu
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Eugenio Martin, Maria E.
    Instituto Nacional de Investigacion y Tecnologias Agrarias y Alimentarias.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Improvement of kraft pulp bleaching by treatments with laccase, urea, and refining2013In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 67, no 6, p. 651-658Article in journal (Refereed)
    Abstract [en]

    Unbleached Eucalyptus kraft pulps were treated by three methods and the bleaching effects have been evaluated. The treatments were performed by a laccase mediator system (LMS), refining (R), and urea (U) alone and in combination of these methods. The bleached pulps were characterized in terms of κ number, hexenuronic acid content, brightness, and viscosity. In addition, the lignin-carbohydrate complexes (LCCs) were fractionated and characterized with regard to the fractionation yield, lignin content, and carbohydrate composition. Moreover, the 1 H nuclear magnetic resonance spectra were recorded and the thioacidolysis-gas chromatography and thioacidolysis-size exclusion chromatography analyses were performed. The LMS treatment resulted mainly in a slightly better delignification as manifested by a κ number (K no.) reduction of 0.8 units. The effects of the U treatment included delignification (1.4 κ units), hexenuronic acid removal (3 μ mol g-1), and improved pulp brightness (3.4 ISO units). The R treatment darkened the pulp (3 ISO units), whereas the bleaching of the R-pulp by subsequent LMS or U treatment enhanced the brightness (0.5 unit more) or delignification (0.3 unit more). The residual lignin in the pulp samples was present mainly as xylan-lignin. The Klason lignin content from the xylan lignin fraction decreased as the degree of delignification increased. The pulp darkening followed by the R treatment was interpreted as the result of the formation of condensed lignin structures, but these condensed lignins were substantially removed by the subsequent LMS or U treatment.

  • 475. Duanmu, Jie
    et al.
    Gamstedt, E. Kristofer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Pranovich, Andrey
    Rosling, Ari
    Studies on mechanical properties of wood fiber reinforced cross-linked starch composites made from enzymatically degraded allylglycidyl ether-modified starch2010In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 41, no 10, p. 1409-1418Article in journal (Refereed)
    Abstract [en]

    In a previous work we introduced a new family of thermoset composites of softwood fiber and allylglycidyl ether modified potato starch (AGE-starch with a degree of substitution of 1.3 and 2.3) prepared by hot pressing. To improve the processability of AGE-starch with a DS = 1.3 (LDS-3) and to increase hygromechanical properties, the LDS-3 matrix has now been partially degraded by a-amylase at 45 degrees C (pH 6) for 0.5, 6 and 18 h. The study shows that already a 30 min enzymatic hydrolysis has a marked effect on the modified starch molecular weight and its thermal properties. The new composites with enzyme hydrolyzed AGE-starch, generically named D-LDS-3, showed good fiber dispersion and excellent interface between the fiber and matrix as studied by SEM. Premixes of D-LDS-3 matrix and fiber showed improved processability. The water vapor absorption was evaluated at 43.2% and 82.2% RH and the stiffness and strength properties were measured. The water uptake was shown to be reduced. The strength of neat matrix D-LDS-3-6 at ambient 68% RH reached 63 MPa and Young's modulus 3200 MPa and with 40 wt.% wood fiber reinforcement impressive 128 MPa and 4500 MPa, respectively.

  • 476.
    Duman, Isa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Coke characterization on HZSM-5, Fe/ZSM-5, Ni/ZSM-5, and Fe-Ni/ZSM-5 from Catalytic Fast Pyrolysis of Biomass2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The combustion of fossil fuels has for a long time been a problem from an environmental and sustainability point of view, especially when it comes to the emissions of atmospheric carbon dioxide. The environmental concern has for instance shifted the attention towards finding new sustainable alternatives for producing chemicals and fuels, as a substitute to today’s dependence on fossil based crude oil. Catalytic Fast Pyrolysis of biomass is an excellent way to produce valuable chemicals and fuels using renewable resources. However, the process has some drawbacks, for example rapid deactivation of catalysts due to coke formation. Little is known about the characteristics of the formation of catalytic coke from pyrolysis processes, which should be a vital concern in future industrial processes. This thesis is dedicated to investigate the chemical coke characteristics found on zeolitic catalysts. Four zeolites of the type ZSM-5 were chosen for this thesis to deduce any chemical differences in the coke: HZSM-5, Fe/ZSM-5, Ni/ZSM-5, and Fe-Ni/ZSM-5. The coke were characterized by TGA, GC/MS, and FTIR.

    The results show that Fe/ZSM-5 produced the highest amount of coke compared to the other zeolites, where HZSM-5 had the lowest amount of coke formation. The coke consisted mainly of aromatic and cyclic hydrocarbons, dominated by polycyclic aromatic hydrocarbons. The content of ketones and alcohols in the coke found on HZSM-5 was higher compared to the metal-doped zeolites, while the formation of naphthalenes was lower. The FTIR results also show that coke was mainly comprised of aromatic hydrocarbons. However, traces of alkanes and alkenes reveal that the coke may have a greater variety than the GC/MS analysis suggests.

    The results show interesting features when metals are introduced to the zeolitic structure, at least when it comes to coke formation. The metal-doping of zeolites certainly seems to alter the chemistry of the catalytic reactions, compared to the parent zeolite. The differences in the chemical characteristics found in the coke are certainly interesting, and it could mean that the chemistry of the bio-oil also varies depending on the metals chosen for the ZSM-5. The new properties that metals introduce to the parent catalyst may open up new possibilities in industrial catalytic processes, and allow industries to take more advantage of the great benefits that biomass has to offer.

  • 477. Durruty, J.
    et al.
    Mattsson, T.
    Theliander, Hans
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Local filtration properties of Kraft lignin: The influence of residual xylan2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 179, p. 455-466Article in journal (Refereed)
    Abstract [en]

    The influence of lignin and xylan interactions on the filtration properties of precipitated LignoBoost lignin was investigated. LignoBoost lignin was (i) suspended in acid water with xylan added and (ii) dissolved together with xylan and then re-precipitated. The resulting lignin-xylan mixtures were more difficult to filter than the original LignoBoost lignin, although the formed filter cake was also found more porous in the case of re-precipitated solids. Furthermore, the pressure dependency of the filtration properties was shown to increase after the addition of xylan. One possible explanation based on the findings presented in this paper is that xylan is sorbed at the surface of the lignin agglomerates: it increases the contact area between solid and liquid, thus making the particle structure more porous. The influence of ionic strength was also investigated through the addition of sodium sulphate: it was found that increasing the ionic strength of the slurries made the solids easier to separate, possibly due to a decrease in electrostatic repulsive interactions between the solids and the formation of a denser solid structure.

  • 478.
    Duval, Antoine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    A review on lignin-based polymeric, micro- and nano-structured materials2014In: Reactive & functional polymers, ISSN 1381-5148, E-ISSN 1873-166X, Vol. 85, no SI, p. 78-96Article, review/survey (Refereed)
    Abstract [en]

    Next to cellulose, lignin is the second most abundant biopolymer, and the main source of aromatic structures on earth. It is a phenolic macromolecule, with a complex structure which considerably varies depending on the plant species and the isolation process. Lignin has long been obtained as a by-product of cellulose in the paper pulp production, but had rather low added-value applications. Changes in the paper market have however stimulated the need to focus on other applications for lignins. In addition, the emergence of biorefinery projects to develop biofuels, bio-based materials and chemicals from carbohydrate polymers should also generate large amounts of lignin with the potential for value addition. These developments have brought about renewed interest in the last decade for lignin and its potential use in polymer materials. This review covers both the topics of the direct use of lignin in polymer applications, and of the chemical modifications of lignin, in a polymer chemistry perspective. The future trend toward micro- and nanostructured lignin-based materials is then addressed.

  • 479.
    Dånmark, Staffan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Polyester scaffold: Material design and cell-protein-material interaction2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tissue engineering has emerged as a valid approach for the regeneration and restoration of bone defects. The concept of bone tissue engineering includes degradable scaffolds, osteogenic cells and osteoinductive growth factors either alone or in any combination of these three. The scaffold bulk material and its design, in particular, are essential for reaching clinically relevant treatments. It is essential that the scaffold is biocompatible and acts as a temporary extra-cellular matrix with a porous 3-dimensional structure, supporting adhesion, proliferation and differentiation of osteogenic cells. Yet another criterion of the scaffold is that is must have sufficient mechanical stability to maintain structural integrity and protect the cells with a gradual transfer of mechanical load to the developing tissue. At the same time, the scaffolds needs to be bioresorbable with a controllable degradation rate depending on its application and the rate of tissue regrowth.

    In this thesis, aliphatic polyester scaffolds have been modified and shown to be suitable for bone tissue engineering applications. In addition, a new microfluidic device for live imaging of cell behavior within porous 3-dimensional scaffolds has been developed.

              Highly porous and degradable aliphatic polyester scaffolds with varying pore sizes and interconnected pores were fabricated. The polyesters assayed were random co-polyesters poly(L-lactide-co-ε-caprolactone) [poly(LLA-co-CL)] and poly(L-lactide-co-1,5-dioxepan-2-one) [poly(LLA-co-DXO] and the homopolymer poly(L-lactide) [poly(LLA)]. The inherently different polymers yielded scaffolds with a wide range of properties with respect to surface chemistry, thermal properties, mechanical stability and degradation rate.

    The polyester scaffolds were shown to support the increased proliferation of bone marrow-derived stromal cells (BMSC) as well as enhanced osteogenic differentiation, with increased levels of osteocalcin gene expression, which emphasized their potential to act as cells carriers in bone tissue engineering. The potential of poly(LLA-co-CL) scaffolds and common biomedical polyesters in bone tissue engineering was further enhanced by surface functionalization. This involved two different methods of immobilization of bone morphogenetic protein-2 (BMP-2), a potent bone-growth-inducing factor, to the assayed polyesters. The first method used BMP-2 immobilized to heparin functionalized polyesters, while the second method covalently bonded BMP-2 to grafted linker groups on polyesters. Both immobilization techniques retain the bioactivity of BMP-2, and growth-factor-modified polyesters showed an increasing expression of osteogenic genes and production of osteocalcin in osteoblasts-like cells as well as increased proliferation in the mouse cell line, C3H10T1/2.

    The rate of degradation of electron-beam-sterilized polyester scaffolds and the subsequent loss of mechanical stability were strongly dependent on the chemical, physical and macroscopic architecture of the samples. The degradation rate and loss of mechanical integrity were much greater in porous scaffolds with hydrophilic co-monomers. By incorporating hydrophobic co-monomers with a limited ability to crystalize instead of hydrophilic co-monomers, the mechanical stability was retained for a longer time during the degradation process.

    The polyester supported spreading and flattened the morphology of both BMSC and osteoblast-like cells. The early cell adhesion to synthetic surfaces is mainly governed by the proteins adsorbed from its surrounding fluids. Early adhesion of BMSC to blood-plasma-coated polyesters was limited, despite the ability of the polyesters to adsorb adhesive proteins and expression of appropriate integrins on BMSC. However, adhesion to a purified adhesive matrix protein on the polyesters did occur, suggesting that pretreatment of polyester scaffolds with adhesive proteins or peptides is a feasible way to enhance the efficiency of cell loading into polyester scaffolds. 

                           Polyester scaffolds were combined with microfluidics and soft lithography to develop a new method for high-resolution imaging of live cells within porous scaffolds. The microfluidic device was used to frequently follow live cell proliferation and differentiation on the same spatial location within 3-dimansional porous scaffolds over a period of more than four weeks. This device is attractive for the evaluation of cells and materials intended for tissue engineering.

    We conclude that degradable aliphatic co-polyester scaffolds carefully designed with respect to macroscopic structure, bulk material and surface chemistry are able to meet the specific requirements of various bone tissue engineering applications. In addition, microfluidic devices permit reoccurring high resolution imaging of live cells within porous scaffolds and have a potential as a method of evaluating tissue engineering constructs.

  • 480.
    Dånmark, Staffan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Schander, K.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Arvidson, K.
    Mustafa, K.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    In vitro and in vivo degradation profile of aliphatic polyesters subjected to electron beam sterilization2011In: ACTA BIOMATERIALIA, ISSN 1742-7061, Vol. 7, no 5, p. 2035-2046Article in journal (Refereed)
    Abstract [en]

    Degradation characteristics in response to electron beam sterilization of designed and biodegradable aliphatic polyester scaffolds are relevant for clinically successful synthetic graft tissue regeneration Scaffold degradation in vitro and in vivo were documented and correlated to the macroscopic structure and chemical design of the original polymer The materials tested were of inherently diverse hydrophobicity and crystallinity poly(L-lactide) (poly(LLA)) and random copolymers from L-lactide and epsilon-caprolactone or 1.5-dioxepan-2-one, fabricated into porous and non-porous scaffolds After sterilization, the samples underwent hydrolysis in vitro for up to a year In vivo, scaffolds were surgically implanted into rat calvarial defects and retrieved for analysis after 28 and 91 days In vitro, poly(L-lactide-co-1, 5-dioxepan-2-one) (poly(LLA-co-DXO)) samples degraded most rapidly during hydrolysis, due to the pronounced chain-shortening reaction caused by the sterilization. This was indicated by the rapid decrease in both mass and molecular weight of poly(LLA-co-DXO). Poly(L-lactide-co-epsilon-caprolactone) (poly(LLA-co-CL)) samples were also strongly affected by sterilization, but mass loss was more gradual; molecular weight decreased rapidly during hydrolysis Least affected by sterilization were the poly(LLA) samples, which subsequently showed low mass loss rate and molecular weight decrease during hydrolysis. Mechanical stability varied greatly. poly(LLA-co-CL) withstood mechanical testing for up to 182 days, while poly(LLA) and poly(LLA-co-DXO) samples quickly became too brittle Poly(LLA-co-DXO) samples unexpectedly degraded more rapidly in vitro than in vivo. After sterilization by electron beam irradiation, the three biodegradable polymers present widely diverse degradation profiles, both in vitro and in vivo. Each exhibits the potential to be tailored to meet diverse clinical tissue engineering requirements

  • 481. Dörr, H.
    et al.
    Koturbash, Taras
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. GasQuaL AB, Brinellvägen 68, 114 28 Stockholm, Sweden.
    Kutcherov, Vladimir G.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Review of impacts of gas qualities with regard to quality determination and energy metering of natural gas2019In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 30, no 2, article id 022001Article in journal (Refereed)
    Abstract [en]

    Diversification of gas supply via the liberalization of the gas trade, the discovery of new fossil gas sources, and the increasing use of renewable gases, are favoring pronounced and more frequent fluctuations in gas quality. The knowledge of gas quality is crucial for custody transfer, and safe, efficient and low-emission operation of gas-driven processes. The onsite measurement of gas quality by the operators of gas production facilities, gas grids, gas storage and gas utilization facilities is an emerging requirement. This paper describes several different approaches for determining gas quality by direct, indirect and inferential methods based on the physicochemical properties of gas. Special emphasis is devoted to a discussion on the miniaturization of gas quality sensors and the incorporation of hydrogen detection and measurement into these sensors, due to potential hydrogen admixture to natural gas. In addition, an overview and analysis of the regulatory and normative requirements for gas quality measurements are presented. Furthermore, an overview of gas quality measurement devices and sensors, recent developments as well as challenges and benefits associated with gas quality measurement instrumentation, are provided.

  • 482.
    Ebadat, Afrooz
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Valenzuela, Patricio Esteban
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Rojas, Cristian R.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Wahlberg, Bo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Model Predictive Control oriented experiment design for system identification: A graph theoretical approach2017In: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 52, p. 75-84Article in journal (Refereed)
    Abstract [en]

    We present a new approach to Model Predictive Control (MPC) oriented experiment design for the identification of systems operating in closed-loop. The method considers the design of an experiment by minimizing the experimental cost, subject to probabilistic bounds on the input and output signals due to physical limitations of actuators, and quality constraints on the identified model. The excitation is done by intentionally adding a disturbance to the loop. We then design the external excitation to achieve the minimum experimental effort while we are also taking care of the tracking performance of MPC. The stability of the closed-loop system is guaranteed by employing robust MPC during the experiment. The problem is then defined as an optimization problem. However, the aforementioned constraints result in a non-convex optimization which is relaxed by using results from graph theory. The proposed technique is evaluated through a numerical example showing that it is an attractive alternative for closed-loop experiment design.

  • 483. Ebin, B.
    et al.
    Gümen, S.
    Arslan, C.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Electrochemical properties of nanocrystalline LiFe xMn 2-xO 4 (x = 0.2-1.0) cathode particles prepared by ultrasonic spray pyrolysis method2012In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 76, p. 368-374Article in journal (Refereed)
    Abstract [en]

    The nanocrystalline LiFe xMn 2-xO 4 (x = 0.2-1.0) particles were prepared by ultrasonic spray pyrolysis method using nitrate salts of ingredients at 800°C in air atmosphere. Particle properties were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. Besides, cyclic voltammetry and galvanostatic tests were performed to investigate the effects of the iron substituent amount on electrochemical behavior. Particle characterization studies show that nanocrystalline particles have spinel structure and they are in submicron size range with spherical morphology. The lowest iron doped sample (LiFe 0.2Mn 1.8O 4) exhibits 117 mAh g -1 cumulative discharge capacity at 0.5 C and 88% capacity retention for 4 V plateau after 50 cycles. At higher iron concentrations, substituent tends to occupy the 8a tetrahedral sites, which prevent the lithium transport in the lattice during charge-discharge process. Increasing of the iron amount in the spinel structure causes the deterioration of the electrochemical performance.

  • 484. Ebin, B.
    et al.
    Gürmen, S.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Electrochemical properties of nanocrystalline LiCu xMn 2-xO 4 (x = 0.2-0.6) particles prepared by ultrasonic spray pyrolysis method2012In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 136, no 2-3, p. 424-430Article in journal (Refereed)
    Abstract [en]

    The nanocrystalline LiCu xMn 2-xO 4 (x = 0.2-0.6) particles were prepared by ultrasonic spray pyrolysis method using lithium nitrate, manganese nitrate and copper nitrate salts at 800 °C in air atmosphere. Particle properties were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. Besides, voltammetric and galvanostatic tests were performed to investigate the effects of the copper substituted on electrochemical behavior. Particle characterization studies showed that low copper substituted nanocrystalline particles had single spinel structure, and increasing amount caused tendency of second spinel phase formation. Particles, ranging between 250 nm and 1.5 μm size, were formed by aggregation of nanoparticles. The cumulative discharge capacities of LiCu 0.2Mn 1.8O 4 were determined as 122, 105 and 87 mAh g -1 at 0.5, 1 and 2 C rates, respectively between 4.8 and 3 V potential range. The capacity fade is 44% of initial capacity after 50 cycles at 0.5C rate. Results showed that electrochemical properties of LiCu xMn 2-xO 4 (x = 0.2-0.6) particles were impaired by increasing Cu substitute due to the second phase formation and ionic displacement in the lattice.

  • 485. Ebin, Burcak
    et al.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Gurmen, Sebahattin
    Preparation and electrochemical properties of nanocrystalline LiBxMn2-xO4 cathode particles for Li-ion batteries by ultrasonic spray pyrolysis method2015In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 620, p. 399-406Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline LiBxMn(2-x)O(4) (x = 0.1-0.4) particles are prepared by ultrasonic spray pyrolysis using lithium nitrate, manganese nitrate and boric acid at 800 degrees C in an air atmosphere. The materials properties are characterized by X-ray diffraction, scanning electron microscopy, and atomic absorption spectroscopy. The electrochemical behaviors are investigated with cyclic voltammetry and galvanostatic techniques. The particle characterization studies show that nanocrystalline particles have spinel structure of submicron size with spherical morphology. All boron substituted lithium manganese oxide spinels show improved cycling performance. Among them, LiB0.3Mn1.7O4 particles exhibit 92 mAh g(-1) discharge capacity and 82% capacity retention after 50 cycles at a 0.5 C rate. The higher degree of atomic ordering and the avoidance of the formation of a glass phase in LiBxMn2-xO4 materials are responsible for the better electrochemical performance.

  • 486. Edberg, Jesper
    et al.
    Malti, Abdellah
    Granberg, Hjalmar
    Hamedi, Mahiar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Crispin, Xavier
    Engquist, Isak
    Berggren, Magnus
    Electrochemical circuits from 'cut and stick' PEDOT: PSS-nanocellulose composite2017In: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 2, no 4, article id 045010Article in journal (Refereed)
    Abstract [en]

    We report a flexible self-standing adhesive composite made from PEDOT:PSS and nanofibrillated cellulose. The material exhibits good combined mechanical and electrical characteristics (an elastic modulus of 4.4 MPa, and an electrical conductivity of 30 S cm(-1)). The inherent self-adhesiveness of the material enables it to be laminated and delaminated repeatedly to form and reconfigure devices and circuits. This modular property opens the door for a plethora of applications where reconfigurability and ease-of-manufacturing are of prime importance. We also demonstrate a paper composite with ionic conductivity and combine the two materials to construct electrochemical devices, namely transistors, capacitors and diodes with high values of transconductance, charge storage capacity and current rectification. We have further used these devices to construct digital circuits such as NOT, NAND and NORlogic.

  • 487.
    Edlund, Ulrica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    A controlled radical polymerization route to polyepoxidated grafted hemicellulose materials2014In: Polimery, ISSN 0032-2725, Vol. 59, no 1, p. 60-65Article in journal (Refereed)
    Abstract [en]

    Polyfunctional copolymers were prepared from the major softwood hemicellulose polysaccharide, i.e. O-acetylated galactoglucomannan (AcGGM) through a grafting-from controlled radical polymerization. AcGGM was functionalized with brominated pendant groups that served as initiating species in the subsequent Cu(0) mediated radical polymerization of glycidyl methacrylate (GMA). A linear relationship of ln[GMA](0)/[GMA] (the index 0 refers to the initial value) versus reaction time up to conversions of 80 % suggests a first order rate of propagation and a "living" polymerization.

  • 488.
    Edlund, Ulrica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Sauter, Tilman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Covalent VEGF protein immobilization on resorbable polymeric surfaces2011In: Polymers for Advanced Technologies, ISSN 1042-7147, E-ISSN 1099-1581, Vol. 22, no 12, p. 2368-2373Article in journal (Refereed)
    Abstract [en]

    Vascular endothelial growth factor type protein (VEGF), a potent angiogenic effector molecule, was successfully covalently immobilized onto the surfaces of the resorbable polymers poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) (PCL) through a three-step strategy. The surfaces were first covalently grafted with poly(acrylic acid) using non-destructive and solvent free vapor-phase grafting. A diamine spacer was coupled to the carboxylic acid pendant groups on the graft chains using EDC/NHS chemistry and VEGF was finally covalently attached to the amine linkers. The chemistry and topography of the modified substrates were quantitatively and qualitatively verified with XPS, ATR-FTIR, UV-VIS, SEM, and ELISA.

  • 489.
    Edlund, Ulrica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Svensson, Marie
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Microsphere valorization of forestry derived hydrolysates2012In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 48, no 2, p. 372-383Article in journal (Refereed)
    Abstract [en]

    A value-adding approach to the material utilization of non-cellulosic polysaccharides (NCPs) released from the lignocellulosic feedstock was realized via the formulation of renewable microspheres from wood hydrolysates using a purposely elaborated all edible water-in-oil emulsion technique. Four compositionally different hemicellulose rich wood hydrolysates were recovered from process waters in pulping and other hydrothermal treatments of hardwood and softwood. Multivariate screening designs were employed allowing for the identification and quantitation of significant process parameters and interaction effects governing the conversion of hydrolysates into small, smooth and well-defined microspheres with narrow size dispersity.

  • 490.
    EDRISI, KEYVAN
    KTH, School of Chemical Science and Engineering (CHE).
    Fastställande av PGM-tillgänglighet för dieseloxidationskatalysator med hjälp av kemisorption2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Diesel Oxidation Catalyst (DOC) is subjected to harsh conditions, causing its performance to

    diminish over time as the result of different aging mechanisms, which either decreases or lowers the

    accessibility to the catalyst’s active sites. Previous work using chemisorption to quantify aging progression

    has resulted in a reproducibility of 17%. In this study it has been attempted to lower this, while

    also performing performance evaluations to see if correlations exist between dispersion and Light-Off

    Temperature (LOT).

    Two catalysts have been investigated, LLC (Low Loading Catalyst) and HLC (High Loading Catalyst).

    These were hydrothermally aged at 600 C, 700 C and 800 C. In addition to these, two HLC engine cell

    samples were also investigated.

    To ensure sample homogeneity, different sample preparation methods were investigated. Catalyst samples

    were crushed, or had their washcoat layer removed, or were milled and then sieved. A total of 5 runs were

    done using fresh catalysts of LLC and HLC to calculate the standard deviation. Evaluation of performance

    was done on all samples using Synthetic Catalyst Activity Testing (SCAT).

    It was deemed that the only viable sample preparation method was to mill and sieve as other methods

    would be hard to reproduce. The results showed that the reproducibility for LLC was %STD = 4% and

    for HLC %STD = 2%. For LLC, a correlation between catalytic activity and dispersion was found. The

    activity dropped with respect to the dispersion in a close to linear fashion without a large effect on BET

    surface area. For HLC the dispersion decreased largely upon hydrothermal aging, however no correlation

    was found with the activity; only when aged at 800 C a significant change in LOT was noted. The BET

    surface area measurements were inconsistent. Lower dispersion sometimes resulted in higher surface area.

    Engine cell samples exhibited notable decrease in dispersion, but not in surface area, and did not correlate

    to the hydrothermally aged catalysts, which might be due to other effects inhibiting CO chemisorption

    during measurements.

  • 491. Ehrl, Lyonel
    et al.
    Soos, Miroslav
    Morbidelli, Massimo
    Bäbler, Matthäus
    Institute of Process Engineering, Dept. of Mechanical and Process Engineering, ETH Zurich.
    Dependence of Initial Cluster Aggregation Kinetics on Shear Rate for Particles of Different Sizes Under Turbulence2009In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 55, no 12, p. 3076-3087Article in journal (Refereed)
    Abstract [en]

    Initial aggregation kinetics for three particle sizes and broad range of Péclet numbers were investigated under turbulent conditions in stirred tank. This allowed us to observe the transition from diffusion-controlled to purely shear-induced aggregation. The evolution of the root-mean-square radius of gyration, zero-angle intensity of scattered light, and obscuration was obtained by small-angle static light scattering. For a given particle sizethe measured evolution of all integral quantities obtained for various volume averageshear rates (G), scales with a dimensionless time, τexp = αexp × (G) × φ × t. The experimentally obtained aggregation efficiency αexp, follows the power law αexp = Pe-n, where Pe is the primary particle Péclet number. With increasing particle size a decrease in n is observed in accordance with theory and literature data. As previously predicted by population balance equation simulations three aggregationregimes were observed experimentally.

  • 492.
    Eita, Mohamed
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    In situ study of the adsorption of humic acid on the surface of aluminium oxide by QCM-D reveals novel features2011In: SOFT MATTER, ISSN 1744-683X, Vol. 7, no 2, p. 709-715Article in journal (Refereed)
    Abstract [en]

    Novel features of the adsorption of humic acid on the surface of aluminium oxide were revealed by means of an in situ study by quartz crystal microbalance with dissipation (QCM-D). The adsorption of humic acid on the surface of aluminium oxide shows a special case at pH 3 where the adsorption takes place in two steps. Each step has characteristic thickness, kinetics and viscoelasticity. While the first step shows low thickness, fast kinetics and almost no viscoelastic character, indicating a rigidly adsorbed humic acid monolayer, the second step is of much higher thickness, slower kinetics and with significant viscoelastic character, indicating a large diffuse layer with significant bulk contributions. In contrast, adsorption at pH 5 and 6.8 was found to be limited to a monolayer which is more rigid at pH 5 than at pH 6.8. Ellipsometry and X-ray photoelectron spectroscopy (XPS) were used to prove and quantify the adsorption in the dry state. The monolayer thickness measured by ellipsometry is close to the Sauerbrey thickness obtained by QCM-D. Adsorption takes place at a dilute concentration of 1 mg L-1, followed by saturation at a concentration of 10-20 mg L-1. XPS spectra of the carbon 1s peak indicated almost no desorption of the adsorbed humic acid layer after immersion in water for 48 hours, implying irreversible adsorption based on a strong binding between humic acid and aluminium oxide.

  • 493.
    Eita, Mohamed
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Insight into the adsorption of humic acid/Gd(3+) complex on the surface of Al(2)O(3) studied in situ by QCM-D and ex situ by ellipsometry and XPS2011In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 7, no 16, p. 7424-7430Article in journal (Refereed)
    Abstract [en]

    The adsorption of humic acid (HA) on an Al(2)O(3) surface in the presence of Gd(3+) was studied in situ by quartz crystal microbalance with dissipation (QCM-D) and ex situ by ellipsometry and XPS. Adsorption of a HA/Gd(3+) complex yielded an adlayer of a mass of 354 ng cm(-2), the adlayer is characterized by a relatively high dissipation indicating a significant viscoelastic character. The viscoelasticity is enhanced by the salt and water molecules penetrating the adlayer causing it to stretch. The dry state average thickness of the adlayer is about 23 angstrom as measured by ellipsometry. Ellipsometry revealed a slower kinetics in the case of HA/Gd(3+) adsorption than that of HA alone. XPS spectra proves the adsorption and demonstrates quantitatively that the adsorption of HA/Gd(3+) and HA show the same trend, except for the higher adsorption in the case of HA/Gd(3+) compared with HA. The structure of the HA/Gd(3+) adlayer may be assumed according to the results of the three techniques to consist of a monolayer of HA bound directly to the surface of Al(2)O(3) and connected via a Gd(3+) bridge to a HA upper layer.

  • 494.
    Ejdeholm, Daniel
    KTH, School of Chemical Science and Engineering (CHE).
    Mechanical Properties of Corroded Polypropylene2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To improve the service reliability of polymeric materials used in pickling environments the aim for this research project was to investigate how the corrosion of PP, exposed to mixed acid, changes its mechanical properties. It was found that PPH-β and PPB has a better resistance to the mixed acid environment both in the corrosion rate and impact strength compared to PPH-α and PPR. Further investigation showed that the penetration depth of the nitration is equal in the material exposed to only nitric acid. A useful method has been developed that can, in a relative short time period, give answers to the selected material´s adequacy for this specific environment. Materials that were tested were in the form of commercially available pipes. The samples were exposed to mixed acid from the inside for 7-27 days at temperatures of 60°C and 80°C. The corrosion rates were determined by pH-indicator and FTIR line-scans. The results were compared to pipes that had been in service for 2 years. The impact strength was determined by Charpy impact testing both on the inside and outside of the pipe walls. No changes in impact properties were found from impacts made to the inside of the pipe.

  • 495.
    Ejenstam, Jesper
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Corrosion resistant alumina-forming alloys for lead-cooled reactors2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Generation IV nuclear power technologies provide attractive solutions to the common issues related to conventional nuclear power plants currently in operation worldwide. Through a significant reduction of the long-term radiotoxicity of nuclear waste, a more efficient use of nuclear fuel resources, and implementation of inherent safety features, Generation IV will make nuclear power sustainable and thus increase the public acceptance of nuclear power. Due to its attractive safety features, the lead-cooled fast reactor (LFR) is one of the most studied Generation IV reactor concepts currently. It is well known that liquid lead is corrosive to steels at elevated temperatures, thus limiting the operation temperature of the LFR. The use of alumina-forming FeCrAl alloys has been proposed to mitigate oxidation and corrosion issues. Commercial FeCrAl alloys have Cr-concentrations typically about 20 wt. % and are thus prone to α-α’ phase separation and embrittlement at temperatures up to about 500 °C. Reducing the Cr-concentration to levels around 10 wt. % would theoretically resolve the said issue. However, the oxidation and corrosion resistance may be impaired. In the scientific literature, compositional limits indicating the formation of protective alumina layers at various temperatures have been presented. Long-term corrosion studies are however scarce. Moreover, in-depth studies on the compositional limits regarding α-α’ phase separation are lacking. In this thesis, the long-term (up to 10,000 h) corrosion resistance and phase stability of alumina-forming alloys are studied at temperatures up to 550 °C. In addition, the influence of reactive elements (RE), e.g. Ti, Zr, and Y, on the liquid lead corrosion resistance of Fe10CrAl alloys is evaluated. By balancing the reactive element and the carbon content, with respect to carbide formation, it is demonstrated in this thesis that it is possible to form protective alumina layers on Fe10Cr4Al alloys from 450 °C, despite the low Al and Cr concentrations. It was found that the RE/carbon ratio needed to form protective alumina layers on Fe10Cr4Al alloys must be larger than unity to mitigate the detrimental effect of Cr-carbide formation.  The underlying phenomena are discussed, and a mechanism is suggested based on the outcome of the long-term oxidation studies. The phase stability of Fe10CrAl alloys was studied through thermal aging experiments in the temperature interval of 450 to 550 °C. In addition, the results were well reproducible using a developed Kinetic Monte Carlo (KMC) model of the FeCrAl system. Furthermore, the model indicated that the Cr-concentration should be limited to about 11 wt. % in a FeCr4Al alloy to mitigate α-α’ phase separation at all temperatures of interest for an LFR. The liquid lead corrosion resistance of alumina-forming austenitic stainless steels was shown to be superior compared to regular stainless steels, albeit the effect of ferrite stabilizing elements needs to be further addressed. The results included in this thesis provide a valuable input on the key issues related to the development of corrosion resistant alumina-forming alloys of interest for liquid lead applications. Moreover, the superior oxidation properties of the studied alumina-forming alloys make them of interest for use in other energy applications, where corrosion issues limits the operation temperature and thus the efficiency.

     

  • 496.
    Ejenstam, Jesper
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Thuvander, Mattias
    Olsson, Pär
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Physics.
    Rave, Fernando
    Szakalos, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Microstructural stability of Fe–Cr–Al alloys at 450–550 °C2015In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 457, p. 291-297Article in journal (Refereed)
    Abstract [en]

    Iron–Chromium–Aluminium (Fe–Cr–Al) alloys have been widely investigated as candidate materials for various nuclear applications. Albeit the excellent corrosion resistance, conventional Fe–Cr–Al alloys suffer from α–α′ phase separation and embrittlement when subjected to temperatures up to 500 °C, due to their high Cr-content. Low-Cr Fe–Cr–Al alloys are anticipated to be embrittlement resistant and provide adequate oxidation properties, yet long-term aging experiments and simulations are lacking in literature. In this study, Fe–10Cr–(4–8)Al alloys and a Fe–21Cr–5Al were thermally aged in the temperature interval of 450–550 °C for times up to 10,000 h, and the microstructures were evaluated mainly using atom probe tomography. In addition, a Kinetic Monte Carlo (KMC) model of the Fe–Cr–Al system was developed. No phase separation was observed in the Fe–10Cr–(4–8)Al alloys, and the developed KMC model yielded results in good agreement with the experimental data.

  • 497.
    Ek, Mattias
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    Shu, Q. F.
    van Boggelen, J.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
    A new approach towards dynamic modelling of dephosphorisation in converter process2012In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 39, p. 77-84Article in journal (Refereed)
    Abstract [en]

    A new approach was made to model the dephosphorisation process in a 300 tons basic oxygen furnace converter with three argon gas inlets. The main feature of the new approach was to utilise the velocity vectors obtained by computational fluid dynamics (CFD) simulation in a standalone model. The CFD simulation was carried out using commercial software COMSOL Multiphysics. In the standalone model, the steel melt domain was sliced into 1000 cells. The calculated velocity vector in each cell was assumed constant. Based on the imported velocity vectors from the CFD calculation, the mass transfer of carbon and phosphorus was calculated by taking into account the slag-metal reactions. The mass exchange between slag and metal was considered to be dominated by the metal droplet formation due to the oxygen jet. The convergence of the model calculation and the promising comparison between the model prediction and the industrial data strongly suggested that the proposed approach would be a powerful tool in dynamic process control. As a preliminary step, the model only simulated the process after the formation of slag-metal-gas emulsion. Note that the present work is intended to establish a structure of the model. More precise descriptions of other process aspects need to be included before the model can be practically employed in a dynamic controlling system.

  • 498.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Cellulose, cellulose regenerates and derivatives2009Conference paper (Refereed)
  • 499.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Delignification and bleaching of the future pulp mill2002Conference paper (Refereed)
  • 500.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    New Cell. Innovative Biopolymers2006Conference paper (Refereed)
78910111213 451 - 500 of 2454
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