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  • 151.
    Kusar, Henrik
    et al.
    Laboratory of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia.
    Hocevar, S.
    Laboratory of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia.
    Levec, J.
    Laboratory of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia.
    Kinetics of the water-gas shift reaction over nanostructured copper-ceria catalysts2006Inngår i: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 63, nr 3-4, s. 194-200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water–gas shift reaction was studied over two nanostructured CuxCe1−xO2−y catalysts: a Cu0.1Ce0.9O2−ycatalyst prepared by a sol–gel method and a Cu0.2Ce0.8O2−y catalyst prepared by co-precipitation method. A commercial low temperature water–gas shift CuO–ZnO–Al2O3 catalyst was used as reference. The kinetics was studied in a plug flow micro reactor at an atmospheric pressure in the temperature interval between 298 and 673 K at two different space velocities: 5.000 and 30.000 h−1, respectively. Experimentally estimated activation energy, Eaf, of the forward water–gas shift reaction at CO/H2O = 1/3 was 51 kJ/mol over the Cu0.1Ce0.9O2−y, 34 kJ/mol over the Cu0.2Ce0.8O2−y and 47 kJ/mol over the CuO–ZnO–Al2O3 catalyst. A simple rate expression approximating the water–gas shift process as a single reversible surface reaction was used to fit the experimental data in order to evaluate the rate constants of the forward and backward reactions and of the activation energy for the backward reaction.

  • 152.
    Kusar, Henrik
    et al.
    Laboratory of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia.
    Hocevar, Stanko
    Levec, Janez
    Water-Gas Shift Reaction Kinetics Over Nanostructured Copper-Ceria Catalysts2006Konferansepaper (Fagfellevurdert)
  • 153.
    L'ABBATE, MARIO ENRICO
    KTH, Skolan för kemivetenskap (CHE).
    Hydrokrackning av FT vaxer på ädelmetall / kiseloxid - aluminiumoxidkatalysatorer: en experimentell och modelleringsstudie2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Synthetic fuel production employing the Fischer-Tropsch (FT) technology will, most likely, play an important role in the future energy system. FT waxes can be upgraded to middle distillates through a hydroprocessing step that combines isomerization and cracking reactions.

    Different catalysts can be employed in the hydroconversion of FT waxes. It is usually carried out on bifunctional catalysts that possess a metal and an acidic function. The former provides the hydrogenation/dehydrogenation activity while the latter catalyzes isomerization and cracking reactions. Due to the absence of poisoning compounds, noble metals (e.g. Pt, Pd) can be employed together with a mesoporous silica-alumina support. The aim of this study was to prepare and test noble metal/silica-alumina catalysts for the hydroconversion of Fischer-Tropsch waxes. A Pd- and a Pt-based catalyst were prepared and fully characterized according to commonly used techniques. From these analyses, it was found that a higher metal dispersion and a lower total acidity characterize the Pt-based catalyst. The experimental testing demonstrated that the Pt-based catalyst is the most suitable for the hydroconversion of FT waxes since it possesses higher activity (evaluated as C22+ conversion) and higher selectivity towards the middle-distillate fraction (i.e. the desired product). Furthermore, both catalysts were tested under about 200 hours on stream showing a good stability.

    The last part of this study was devoted to the modelling of the hydroconversion reaction. Firstly, a deep literature review of the already published models was carried out. Afterwards, the considered most advanced model was implemented in a commercial simulator in order to test its prediction power with respect to the main features of the reacting system. In addition, an improved version of this model was proposed considering the variability of a stoichiometric factor, previously kept constant. The former model and its improved version were tested and compared according to a statistical study. Thanks to this, it was possible to state that the improved hydroconversion model has a slightly better prediction power.

    Finally, a comparison of the two catalysts was carried out by evaluating their kinetic constants derived from the improved model. From this point of view, the Pd-based catalyst presents stronger Langmuir adsorption constants. This could explain its lower reactivity since the involved species have a higher energy barrier prior to desorb. Moreover, this catalytic system presents a higher probability of producing isomerized fragments after a cracking after (86% on Pd, 78% on Pt on average). This suggests that more isomerization steps occur in the case of the Pd-based catalyst prior to undergo cracking reactions. This aspect could add some further explanations to its lower activity since the conversion of high boiling point fractions is slower.

  • 154.
    Lazarevic, David
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630). CNRS Troyes University of Technology, France; Veolia Environnement Recherche et Innovation, France.
    Buclet, Nicolas
    University of Technology, Troyes.
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    The influence of the waste hierarchy in shaping European waste management: the case of plastic waste2010Inngår i: Regional Development Dialogue, ISSN 0250-6505, Vol. 31, nr 2, s. 124-148Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Waste management in Europe has experienced significant changes since the 1970s. The majority of Member State waste management regimes have shifted from policies based on the control of waste disposal activities, to include goals for waste prevention and recovery. The rapid increase of plastic packaging recycling in Germany had a number of unintended consequences. In the first years of the Packaging Ordinance, the majority of plastic packaging collected was exported to China, Eastern Europe, and other EU Member States due to lack of national capacity. The setting of high recycling targets for plastic packaging waste between 1991 and 1998 and the prohibition of incineration with energy recovery was a key driver of recycling technology innovation in Germany. When adopting new principles to serve as the foundation of belief, they should synchronize with the existing waste management myths of individual regions, as myths may differ from region to region illustrating different cultural ideals.

  • 155.
    Ledung, Greger
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Heterogenization of a Cobalt Porphyrin Catalyst Investigated by Scanning Probe Microscopy and X-Ray Photoelectron Spectroscopy: The Effect on Catalysis of Oxidation Reactions2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Construction of advanced materials through self-assembly on the molecular level is an important route to achieve novel functionality. Self-assembly of thiols onto gold has during the last decades shown greate promise in the creation of functional nanomaterials, such as sensors or catalysts, but for many applications silicon should be a better substrate since it offers semiconducting properties and better processing abilities in addition to being cheaper. This work describes an efficient novel method to incorporate reactive disulfide bonds onto a silica surface under mild reaction conditions. The reactive thiol groups introduced onto the silica surface will be oxidized but is then converted into highly reactive thiopyridyl groups, which can easily be utilized for further organic synthesis involving thiol-containing molecules.

    Cobalt tetraarylporphyrins with thioacetate-functionalized carbon chains on the aryl groups were synthesized (CoTPP-L) and were used as a model system for investigating catalytic activity in homogeneous and heterogeneous oxidation catalysis. For heterogeneous catalysis CoTPP-L was immobilized onto gold surfaces through thiol-gold self-assembly, and onto silica surfaces by the above mentioned disulfide exchange method.

    The properties of the molecular layers were characterized on the molecular level by means of X-ray photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM). The immobilization on gold surfaces took place through the formation of multiple thiolate bonds and it could be controlled by varying the preparation scheme. More thiolate bonds form if the thioacetyl protective groups of the thiol linkers are cleaved off prior to immobilization. The CoTPP-L molecules were in all cases found to form stable disordered monolayers on gold surfaces. On silica surfaces the CoTPP-L forms patchwise multilayers.

    The catalytic performance of the heterogenized systems (CoTPP-L immobilized onto gold or silicon wafers) was evaluated and it was found that the strong inactivation observed for their homogeneous congener was avoided. As a result, the turnover number per molecule in heterogeneous catalysis was at least 100 times higher than that of the corresponding homogeneous catalyst. It is thus demonstrated that the performance of these catalysts can be dramatically improved if the catalyst arrangement can be controlled on the molecular level. Work is ongoing to extend the system to high surface area materials.

  • 156. Leppänen, A.
    et al.
    Kinnunen, H.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Enestam, Sonja
    Condensation and deposit formation in the NaCl-Na2SO4 system, an experimental and modeling study2017Inngår i: International Chemical Recovery Conference (ICRC), Halifax, Canada, 2017; Halifax, Canada, 2017Konferansepaper (Fagfellevurdert)
  • 157.
    Li, Fei
    et al.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Du, Jian
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Li, Xiaona
    Dalian Univ Technol, Sch Environm Sci & Technol, Key Lab Ind Ecol & Environm Engn, Dalian 116024, Peoples R China..
    Shen, Junyu
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Wang, Yong
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Zhu, Yong
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Integration of FeOOH and Zeolitic Imidazolate Framework-Derived Nanoporous Carbon as an Efficient Electrocatalyst for Water Oxidation2018Inngår i: Advanced Energy Materials, ISSN 1614-6832, Vol. 8, nr 10, artikkel-id 1702598Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As a cost-effective catalyst for the oxygen evolution reaction (OER), the potential use of FeOOH is hindered by its intrinsic poor electron conductivity. Here, the significant enhancement of OER activity and long-term stability of electrodeposited FeOOH on zeolitic imidazolate framework-derived N-doped porous carbons (NPCs) are reported. In alkaline media, FeOOH/NPC supported on nickel foam as a 3D electrode delivers a current density of 100 mA cm(-2) at a small overpotential of 230 mV and exhibits a low Tafel slope of 33.8 mV dec(-1) as well as excellent durability, making it one of the most active OER catalysts. Such high performance is attributed to a combined effect of the excellent electron conductivity of NPC and the synergy between FeOOH and NiO derived from Ni substrate.

  • 158.
    Li, Lin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Functional Photo-electrochemical Devices for Solar Cellsand Solar Fuels Based on Molecular Components2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis concerns the development and the study of molecular functional photo-electrochemical cells (PEC) for solar cells and solar fuels.

    The first chapter gives a general introduction about photosynthesis, dye-sensitized solar cell and photo-electrochemical device for water splitting.

    The second chapter describes a TiO2-Co-catalyst electrode manufactured by a direct photo-deposition method. The electrode showed activity for electrochemical water oxidation in an electrochemical device.

    In the third chapter, a photo-electrochemical cell (PEC) with two-electrodes for visible light driven water splitting has been successfully demonstrated. One electrode was a photo-anode, which assembled a ruthenium water oxidation catalyst (complex 1) into a dye-sensitized porous nanostructured TiO2 electrode by employing a cation-exchange membrane (Nafion). The other electrode was platinum which was used as a passive cathode for proton reduction.

    In the fourth chapter, an earth abundant metal complex with an anchoring group (cobalt complex 2) was synthesized and investigated as water oxidation catalyst. This complex was further applied into a photo-anode in a PEC. The photo-anode was assembled by co-sensitization of complex 2 to a dye-sensitized porous nanostructured TiO2 electrode. The PEC device gave ca. 250 υA/cm2 photo-current and 7.2 % IPCE without applying any bias voltage, which is much higher than the reported results in the sample type of PEC. Meanwhile, we have shown that the catalytic effect is not from free cobalt ions, CoOx film or nanoparticles formed in situ by using complex 2 in the device.

    The last two chapters describe an optimization of the NiO films prepared in two steps rather than one step film and applied in p-type DSSCs. This optimized film could adsorb more dye (P1), leading to a significant light harvesting efficiency (LHE) and IPCE in DSSCs. We further combined this P1 sensitized photo-cathode with a hydrogen evolution catalyst (complex 3) and applied this photo-cathode into a PEC for visible light hydrogen evolution.

  • 159.
    Li, Yulin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Analysis of green-house gas emission in China2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today China produces most GHG emissions in the world, which continues increasing the average temperature of the Earth. For the purpose of reducing the emission and reaching the peak of GHG emission before 2030, Chinese government promotes several policies, such as developing renewable energy, importing advanced emission reduction technology and encouraging the production and sales of new energy vehicles.

    In order to estimate the tendency of Chinese GHG emission, a review has been conducted. This review has considered the current Chinese situation, making necessary assumptions and calculating total emission in several relevant sectors independently. By adjusting several key figures, the end result of peak year may be changed.

    The review has proved that the peak year for Chinese GHG emissions will be 2035 under normal condition. If other optimized factors are considered, the peak year could be moved up.

  • 160.
    Lim, Eunhee
    et al.
    University of Cambridge, England; Korea Institute Ind Technology KITECH, South Korea.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Schwartz, Erik
    Radboud University of Nijmegen, Netherlands.
    Cornelissen, Jeroen J. L. M.
    Radboud University of Nijmegen, Netherlands.
    Nolte, Roeland J. M.
    Radboud University of Nijmegen, Netherlands.
    Rowan, Alan E.
    Radboud University of Nijmegen, Netherlands.
    Greenham, Neil C.
    University of Cambridge, England.
    Do, Lee-Mi
    Elect and Telecommun Research Institute ETRI, South Korea.
    Carbazole Functionalized Isocyanide Brushes in Heterojunction Photovoltaic Devices2012Inngår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 12, nr 1, s. 503-507Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, carbazole-containing polyisocyanide (PIACz) brushes were used for photovoltaic devices. A photovoltaic device was fabricated on top of the brushes by spin-coating a suitable acceptor and evaporating an Al cathode. Devices with a poly(N-vinylcarbazole) (PVK) bulk polymer were also prepared for comparison. Interestingly, the brushes showed better photovoltaic characteristics as compared to the blended PVK system. This is attributed to the specific morphologies of the polyisocyanide brushes, which provide a large interfacial area between the donor and acceptor for efficient photogeneration. It was found that the device performance varied according to the molecular size of the incorporated acceptors.

  • 161.
    Lindahl, Niklas
    et al.
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Eriksson, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Groenbeck, Henrik
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Wreland Lindström, Rakel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Wickman, Bjoern
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Fuel Cell Measurements with Cathode Catalysts of Sputtered Pt3Y Thin Films2018Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, nr 9, s. 1438-1445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fuel cells are foreseen to have an important role in sustainable energy systems, provided that catalysts with higher activity and stability are developed. In this study, highly active sputtered thin films of platinum alloyed with yttrium (Pt3Y) are deposited on commercial gas diffusion layers and their performance in a proton exchange membrane fuel cell is measured. After acid pretreatment, the alloy is found to have up to 2.5 times higher specific activity than pure platinum. The performance of Pt3Y is much higher than that of pure Pt, even if all of the alloying element was leached out from parts of the thin metal film on the porous support. This indicates that an even higher performance is expected if the structure of the Pt3Y catalyst or the support could be further improved. The results show that platinum alloyed with rare earth metals can be used as highly active cathode catalyst materials, and significantly reduce the amount of platinum needed, in real fuel cells.

  • 162.
    Lindberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Electrochemical Investigation of the Reaction Mechanism in Lithium-Oxygen Batteries2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Lithium-oxygen batteries, also known as Lithium-air batteries, could possibly revolutionize energy storage as we know. By letting lithium react with ambient oxygen gas very large theoretical energy densities are possible. However, there are several challenges remaining to be solved, such as finding suitable materials and understanding the reaction, before the lithium-oxygen battery could be commercialized. The scope of this thesis is focusing on the latter of these challenges.

    Efficient ion transport between the electrodes is imperative for all batteries that need high power density and energy efficiency. Here the mass transport properties of lithium ions in several different solvents was evaluated. The results showed that the lithium  mass transport in electrolytes based on the commonly used lithium-oxygen battery solvent dimethyl sulfoxide (DMSO) was very similar to that of conventional lithium-ion battery electrolytes. However, when room temperature ionic liquids were used the performance severely decreased.

    Addition of Li salt will effect the oxygen concentration in DMSO-based electrolytes. The choice of lithium salt influenced whether the oxygen concentration increased or decreased. At one molar salt concentration the highest oxygen solubility was 68 % larger than the lowest one.

    Two model systems was used to study the electrochemical reaction: A quartz crystal microbalance and a cylindrical ultramicroelectrode. The combined usage of these systems showed that during discharge soluble lithium superoxide was produced. A consequence of this was that not all discharge product ended up on the electrode surface.

    During discharge the cylindrical ultramicroelectrodes displayed signs of passivation that previous theory could not adequately describe. Here the passivation was explained in terms of depletion of active sites. A mechanism was also proposed.

    The O2 and Li+ concentration dependencies of the discharge process were evaluated by determining the reactant reaction order under kinetic and mass transport control. Under kinetic control the system showed non-integer reaction orders with that of oxygen close to 0.5 suggesting that the current determining step involves adsorption of oxygen. At higher overpotentials, at mass transport control, the reaction order of lithium and oxygen was zero and one, respectively. These results suggest that changes in oxygen concentration will influence the current more than that of lithium.

    During charging not all of the reaction product was removed. This caused an accumulation when several cycles was examined. The charge reaction pathway involved de-lithiation and bulk oxidation, it also showed an oxygen concentration dependence.

  • 163.
    Lindbergh, Göran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Wreland Lindström, Rakel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Teknikbevakning av polymera bränsleceller (PEMFC) 20082008Rapport (Annet (populærvitenskap, debatt, mm))
  • 164.
    Lindelöf, Åsa
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Metangasutsläpp från deponier och osäkerheter i beräkningsmodeller kring detta2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I Sverige finns uppskattningsvis mellan 4000 och 8000 stycken deponier. De flesta av deponierna är nedlagda och år 2001 fanns det 142 stycken aktiva deponier för hushållsavfall. År 2010 hade antalet minskat till 76 stycken.  Vid nedbrytning av organiskt material i deponier bildas metanhaltig deponigas som bidrar till växthuseffekten. Utsläppens omfattning prognostiseras med hjälp av beräkningsmodeller, exempelvis IPCCs. Dessa modeller fordrar att antaganden görs av exempelvis andelen gas som utvinns via gasuppsamlingsutrustningen, det organiska materialets halveringstid och avfallets sammansättning och mängd. I Sverige görs antagandet att 60 procent av deponigasen samlas upp på deponier med gasuppsamlingsutrustning. Rapportens övergripande syfte var att undersöka hur osäkerheterna i de antaganden som görs kan inverka på de prognostiserade deponigasemissionerna. Syftet var också att bedöma om metangasutsläpp från deponier utgör ett stort eller försumbart tillskott av växthusgasutsläpp i jämförelse med andra källor. Detta gjordes genom en känslighetsanalys som baserades på en litteraturstudie, IPCC- prognostiserade metanmängder samt genom intervjuer med deponiägare.

     

    Prognostiserad metangasproduktion från landets deponier jämfördes med uppskattad metangasproduktion, där det senare baserades på utvunna mängder i landet och en uppskattad utvinningsgrad på 60 procent. Prognostiserad metangasmängd jämfördes med en uppskattad mängd metan, där den senare baserades på utvunna gasmängder i landet och uppskattad utvinningsgrad. Omfattningen av emissionerna gjordes genom känslighetsanalys där utvinningsgrad hos gasuppsamlingssystemets varierades mellan 30 och 80 procent. De utvunna gasmängderna har varit relativt konstanta de senaste tio åren trots att antalet deponier med gasuppsamlingsutrustning minskat från 75 till 47 stycken och att deponeringsförbud har instiftats. Den antagna halveringstiden på 7,5 år torde därför vara för lågt ansatt vilket också styrks av den dåliga nedbrytningen i flera äldre deponier, minskade mängder deponerat avfall samt att inget organiskt material deponeras sedan 2005. Sveriges huvudsakliga metankällor är jordbrukssektorn och deponier från avfallssektorn. År 1990 var de prognostiserade utsläppen från de två sektorerna ungefär lika stora. Fram till år 2010 har de prognostiserade utsläppen från deponier halverats medan utsläpp från jordbruket ligger på ungefär samma nivå som tidigare.

     

    Ur den enskilda deponins perspektiv kan det konstateras att utvinningsgraden hos gasuppsamlingssystemet varierar i både ett kortsiktigt och i ett långsiktigt perspektiv. Beroende på när en mätning utförs kommer en viss variation uppvisas i gasutvinningssystemets utvinningsgrad dvs både emitterade och uppsamlade gasmängder varierar mellan mättillfällena.  Det kan konstateras att en stor osäkerhet byggs in i den beräknade årsproduktionen av metangas när metanmängderna beräknas med hjälp av medelvärden från ett fåtal mätningar utförda under korta mätperioder. Statistiska Centralbyrån har gjort beräkningar av den årliga utvinningsgraden. Dessa beräkningar har grundats på faktiska utvunna mängder som jämförts med beräknade totala mängder. För en enskild deponi kan skillnaderna mellan de beräknade och faktiska mängderna vara stora vilket medför att utvinningsgraden eller produktionen är svårbedömd både för den enskilda deponin och på nationell nivå.

     

    Potentialen för gasutvinning i deponier bedöms i det här examensarbetet vara större än vad som har prognostiserats. Perioden för gasuttag sträcker sig längre än vad man trott med anledning av att mycket av det organiska materialet i gamla deponier fortfarande inte har brutits ner, samt att gasproduktion fortfarande sker. Med anledning av de låga driftskostnaderna bör deponigasutvinning fortskrida så länge som det är tekniskt möjligt och ekonomiskt hållbart. Genom provtagningar av avfallet i kombination med mätningar som sträcker sig över längre perioder, skulle bättre kännedom om metangasproduktionen i deponier kunna fås.

  • 165.
    Lindström, Rakel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Kortsdottir, Katrin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Active area determination for porous Pt-electrodes used in PEM fuel cells: Temperature and humidity effects2009Inngår i: Proton Exchange Membrane Fuel Cells 9 / [ed] T. Fuller, C. Hartnig, V. Ramani, H. Uchida, H. Gasteiger, S. Cleghorn, P. Strasser, T. Zawodzinski, D. Jones, P. Shirvanian, T. Jarvi, P. Zelenay, C. Lamy, P. Bele, 2009, s. 1211-1220Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper aim to discuss a proper measure of the electrochemical active area of carbon supported Pt nanoparticle catalyst used in polymer electrolyte membrane (PEM) fuel cells. The cyclic voltammetric determination of hydrogen under potential deposition (Hupd) and carbon monoxide monolayer oxidation (CO stripping) performed in a fuel cell at fuel cell relevant conditions are compared and the influences of operation temperature (25-80 {degree sign}C) and relative humidity (RH) (40-90% RH) are discussed. The results show that both the shape and the charge of the Hupd are strongly dependent on operating conditions. However, for the CO stripping experiments only a negative shift in potential with increasing temperature or humidity was observed in accordance with results from aqueous electrolytes, whereas the charges for CO monolayer oxidation were almost constant for the temperatures investigated.

  • 166.
    Linnas, Ingrid
    KTH, Skolan för kemivetenskap (CHE).
    Catalyst performance in high temperature catalytic combustion2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis was carried out in co-operation between KTH- Royal Institute of Technology, Tallinn University of Technology and ReformTech Heating Technologies Sweden AB. The purpose of this thesis was to evaluate catalyst performance in a catalytic heater developed by ReformTech Heating Technologies Sweden AB. Different catalysts were tested for the combustion of diesel at 5 KW adiabatic power during 1 hour. The catalysts were evaluated based on the temperature profiles, emission results and mechanical durability. The catalyst with ceramic support showed the most promising results for this application with the highest mechanical durability and exhaust emissions below 0,5 ppm for diesel and CO, NOX content in the exhaust gas was negligible .

  • 167.
    Liora, Jackson
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för analytisk farmaceutisk kemi.
    Characterization of the equine metabolites of LGD-4033 in urine using UHPLC-MS(/MS) for doping control purposes2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this project was to study and characterize the metabolitesof LGD-4033 in equine urine, with the final aim of using the results indoping controls in equestrian sports. Urine samples had been taken atdifferent points in time from three horses that had received thesubstance intravenously. The samples were both directly analysed usinga so called dilute-and-shoot approach and were also prepared with amixed mode anion exchange solid phase extraction. All analysis weredone with UHPLC-ESI-MS(/MS) in negative mode. A total of eightmetabolites were found, which were all combinations of phase Ihydroxylation and/or phase II glucuronidation. Of these a total of four(one that is both monohydroxylated and glucuronidated, one that isdihydroxylated, as well as two glucuronidated metabolites) would besuitable for doping control.

  • 168.
    Liu, Jia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Northeast Normal Univ, Natl & Local United Engn Lab Power Batteries, Fac Chem, Changchun 130024, Peoples R China..
    Ma, Yue
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Roberts, Matthew
    Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England..
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Zhu, Jiefang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Highly efficient Ru/MnO2 nano-catalysts for Li-O2 batteries: Quantitative analysis of catalytic Li2O2 decomposition by operando synchrotron X-ray diffraction2017Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 352, s. 208-215Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In-situ or operando quantitative analysis is very important for Li-O2 batteries, in order to properly, accurately and comprehensively evaluate electrocatalysts and characterize Li-O2 electrochemistry in real-time. Synchrotron XRD can provide much higher X-ray intensity and time resolution than traditional in-house diffractometers, and therefore can contribute to quantitative analysis for Li-O2 batteries. Here, operando synchrotron XRD is further developed to quantitatively study Li-O2 batteries with nano catalysts, Ru/MnO2. The time-resolved oxygen evolution reaction (OER) kinetics for Li-O2 cells with Ru/MNT was systematically investigated using operando synchrotron radiation powder X-ray diffraction (SR-PXD). Li2O2 decomposition in the electrodes with Ru/MNT catalysts during galvanostatic and potentiostatic charge processes followed pseudo-zero-order kinetics and showed ideal Coulombic efficiency (close to 100%). Furthermore, it was found that the OER kinetics for a cell with 2 wt% Ru/MNT charged at a constant potential of 4.3 V was even faster than that for a cell with the same amount of pure Ru nanoparticles, which have been considered as a highly active catalyst for Li-O2 batteries. These results indicated that Ru/MNT with a special nanostructure represented a very efficient electrocatalyst for promoting the OER in Li-O2 batteries. We also demonstrate that synchrotron radiation XRD can "highlight" a way to quantitative analysis for Li-O2 batteries.

  • 169.
    Liu, Longcheng
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Shahkarami, Pirouz
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Meng, Shuo
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Solute transport along a single fracture in a porous rock: a simple analytical solution and its extension for modeling velocity dispersion2017Inngår i: Hydrogeology Journal, ISSN 1431-2174, E-ISSN 1435-0157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A simple and robust solution is developed for the problem of solute transport along a single fracture in a porous rock. The solution is referred to as the solution to the single-flow-path model and takes the form of a convolution of two functions. The first function is the probability density function of residence-time distribution of a conservative solute in the fracture-only system as if the rock matrix is impermeable. The second function is the response of the fracture-matrix system to the input source when Fickian-type dispersion is completely neglected; thus, the effects of Fickian-type dispersion and matrix diffusion have been decoupled. It is also found that the solution can be understood in a way in line with the concept of velocity dispersion in fractured rocks. The solution is therefore extended into more general cases to also account for velocity variation between the channels. This leads to a development of the multi-channel model followed by detailed statistical descriptions of channel properties and sensitivity analysis of the model upon changes in the model key parameters. The simulation results obtained by the multi-channel model in this study fairly well agree with what is often observed in field experiments—i.e. the unchanged Peclet number with distance, which cannot be predicted by the classical advection-dispersion equation. In light of the findings from the aforementioned analysis, it is suggested that forced-gradient experiments can result in considerably different estimates of dispersivity compared to what can be found in natural-gradient systems for typical channel widths.

  • 170.
    Lloyd Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Darmastuti, Zhafira
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Bjorklund, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Bur, Christian
    Saarland University, Saarbrücken, Germany.
    Schütze, Andreas
    Saarland University, Saarbrücken, Germany.
    Huotari, Joni
    University of Oulu, Finland.
    Jantunen, Heli
    University of Oulu, Finland.
    Lindqvist, Niclas
    Alstom Power AB, Växjö, Sweden.
    Improved chemical sensors track and control emissions2013Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Sensitive, low-cost silicon carbide-based gas sensors can detect toxic emissions and hazardous nanoparticulate matter in previously untenable environments.

  • 171.
    Lloyd Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Darmastuti, Zhafira
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Bur, Christian
    Saarland University, Saarbrücken, Germany.
    Huotari, Joni
    University of Oulu, Finland.
    Bjorklund, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Lindqvist, Niclas
    Alstom Power AB, Växjö, Sweden.
    Lappalainen, Jyrki
    University of Oulu, Finland.
    Jantunen, Heli
    University of Oulu, Finland.
    Schütze, Andreas
    Saarland University, Saarbrücken, Germany.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Chemical sensor systems for environmental and emission control2013Inngår i: Proc. SPIE Defence, Security + Sensors, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Focusing on environment and health aspects, the importance of monitoring and controlling dangerous gases and particulate matter increases. For this purpose we present a new version of silicon carbide based gas sensors with improved properties and suitable for high temperature and harsh environments such as power plants or car exhausts. Development of sulfur dioxide sensors for a power plant application is described as well as sensors for detection of ammonia in connection with the SCR process where urea is converted to ammonia, which reduces nitric oxide components in the exhausts. We also describe progress on nanoparticle detection, especially related to detection of the content of adsorbed particles through heating and detection of emitted molecules by a sensor array. Some results are also presented from impedance spectroscopy for detection of the concentration of nanoparticles but with the potential to reveal more details about the particles such as shape and kind of particles. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  • 172.
    Lloyd Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Huotari, Joni
    University of Oulu, Finland.
    Bur, Christian
    Saarland University, Saarbrücken, Germany.
    Bjorklund, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Lappalainen, Jyrki
    University of Oulu, Finland.
    Jantunen, Heli
    University of Oulu, Finland.
    Schütze, Andreas
    Saarland University, Saarbrücken, Germany.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Chemical sensor systems for emission control from combustions2013Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 187, nr SI, s. 184-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Environmental and health concern has increased the importance to monitor and control emissions like toxic gases and particulate matter from combustion processes. The silicon carbide-field effect transistor (SiC-FET) technology offers versatile and powerful sensors for gas detection also in combination with combustion of particles. Emission control has been demonstrated e. g. for small and medium sized power plants and diesel exhausts. The potential danger of nanoparticles makes such detectors interesting not only for detection of concentration and size of particles but also detection of the content of particles. Due to the possibility of operating the sensor devices in different independent modes (e. g. temperature- and bias-modulated) the SiC-FET technology also lends itself for the future development of sensor adaptation, self-diagnosis and auto calibration, which is expected to improve the performance of such a combined gas/particle sensor system. Here we report progress on the sensor technology itself, the application of a sensor system as an alarm for ammonia emission and preliminary results of particle detection in diesel exhausts and particles from a power plant and a steel plant.

  • 173.
    Lloyd Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Huotari, Joni
    University of Oulu, Finland.
    Bur, Christian
    Saarland University, Saarbrücken, Germany.
    Lappalainen, Jyrki
    University of Oulu, Finland.
    Schütze, Andreas
    Saarland University, Saarbrücken, Germany.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska högskolan.
    Chemical sensor systems for emission control from combustions2012Inngår i: IMCS 2012, 2012, s. 635-638Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Environmental and health concern has increased the importance to monitor and control emissions from combustion processes like toxic gases and particulate matter. The SiC-FET technology offers versatile and powerful sensors for gas detection also in combination with combustion of particles. Emission control has been demonstrated e.g. for small and medium sized power plants and diesel exhausts. The potential danger of nanoparticles makes such detectors interesting not only for detection of concentration and size of particles but also detection of the content of particles. The SiC-FET technology lends itself for smart sensing and smart data evaluation, which largely improves the information from such a sensor system. Here we report progress on the sensor technology itself, the application of a sensor system as an alarm for ammonia emission and preliminary results of particle detection.

  • 174.
    Lloyd Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten. Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Sobocinski, Maciej
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Halonen, Niina
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Puglisi, Donatella
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten.
    Juuti, Jari
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Jantunen, Heli
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten. Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    LTCC, new packaging approach for toxic gas and particle detection2015Inngår i: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 120, s. 484-487Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Packaging of chemical sensors is still an area, which is not much explored. Low temperature co-fired ceramic, LTCC, packaging offers large advantages in terms of 3D design, integration of advanced functionality and fast processing. SiC based FET gas sensors are possible to integrate directly in the LTCC co-firing process at 850 °C, whereby both high temperature and other advanced applications like ultra-low detection of toxic gases are greatly improved. The LTCC packaging is also used for development of particle detectors as well as packaging for an electrical method to detect toxic effect on cells by particles.

  • 175.
    Lu, Huiran
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Hagberg, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Cornell, Ann M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Flexible and Lightweight Lithium-Ion Batteries Based on Cellulose Nanofibrils and Carbon Fibers2018Inngår i: BATTERIES-BASEL, ISSN 2313-0105, Vol. 4, nr 2, artikkel-id 17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Flexible, low-weight electrodes with integrated current collectors based on chopped polyacrylonitrile carbon fibers (CF) were produced using an easy, aqueous fabrication process, where only 4 wt% of TEMPO-oxidized cellulose nanofibrils (CNF) were used as the binder. A flexible full cell was assembled based on a LiFePO4 (LFP) positive electrode with a CF current collector and a current collector-free CF negative electrode. The cell exhibited a stable specific capacity of 121 mAh g(-1) based on the LFP weight. The CF in the negative electrode acted simultaneously as active material and current collector, which has a significant positive impact on energy density. Stable specific capacities of the CF/CNF negative electrode of 267 mAh g(-1) at 0.1 C and 150 mAh g(-1) at 1 C are demonstrated. The LFP/CNF with CF/CNF, as the current collector positive electrode (LFP-CF), exhibited a good rate performance with a capacity of -150 mAh g(-1) at 0.1 C and 133 mAh g(-1) at 1 C. The polarization of the LFP-CF electrode was similar to that of a commercial Quallion LFP electrode, while much lower compared to a flexible LFP/CNF electrode with Al foil as the current collector. This is ascribed to good contact between the CF and the active material.

  • 176.
    Lualdi, Matteo
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Fischer-Tropsch Synthesis over Cobalt-based Catalysts for BTL applications2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Fischer-Tropsch synthesis is a commercial technology that allows converting synthesis gas, a mixture of CO and H2, into fuels and chemicals. This process could be one of the actors in the reduction of oil dependency of the transportation sector. In fact, it has great potential for producing synthetic fuels also from renewable sources, such as biomass, after its thermochemical conversion (gasification) into synthesis gas. Concerning the quality of a diesel fuel produced with this technology, it has a lower local environmental impact than conventional diesel, since it is practically free of sulphur and nitrogen compounds and yields lower exhaust emissions of hydrocarbons, CO and particulates. The present study focuses on the use of cobalt-based catalysts for the production of diesel. In particular, it looks upon correlation between product selectivities when varying the catalyst properties and the effect of process parameters, such as a low H2/CO ratio, typical of a biomass-derived synthesis gas, and the water partial pressure.

    Different cobalt-based catalysts, with different properties, such as conventional 3-dimensional porous network supports (γ-Al2O3, α-Al2O3, TiO2, SiO2), Co-loading, preparation technique, etc., were investigated in the Fischer–Tropsch reaction at industrially relevant process conditions. For a set of process conditions, a linear relationship seems to exist between the selectivity to methane (and other light products) and higher hydrocarbons (identified by the industrially relevant parameter SC5+, selectivity to hydrocarbons with more than 4 carbon atoms) indicating a common precursor.

    Ordered mesoporous materials (SBA-15), characterized by a 1-dimensional mesoporous network, were tested as model supports and showed the possibility of occurrence of CO-diffusion limitations at diffusion distances much shorter than those required for conventional 3-dimensional porous network supports. The linear relationship mentioned above, derived for conventional supports, was shown to be an efficient tool for indicating whether measured selectivities are affected by CO-diffusion limitations. Some of the catalysts were exposed to H2-poor syngas and to external water addition and the effects on the selectivity relationships were investigated.

    Furthermore, the possibility of internal water-gas shift of a H2-poor syngas with mixtures of Co/γ-Al2O3 and a Cu/ZnO/Al2O3 catalyst was investigated both as a technical solution for direct use of a model bio-syngas in the Fischer-Tropsch synthesis, and as a means to study the effect of indigenous water removal on the reaction rate to hydrocarbons. It was found that removal of indigenously produced water slows down the reaction rate significantly. Lastly, the effect of water partial pressure on the Fischer–Tropsch rate of the Co catalyst supported on narrow-pore γ-Al2O3, on its own, was studied. Inlet water partial pressure was varied by external water vapor addition at different H2/CO molar ratios ranging from 1 to 3. The effect of water showed to be positive on the rate for all the H2/CO ratios, but more significantly at H2-poor conditions. The nature of this positive effect on the rate seems to be unrelated to changes in amounts of amorphous polymeric carbon detectable by temperature-programmed hydrogenation of the spent catalyst.

  • 177.
    Lualdi, Matteo
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Lögdberg, Sara
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Boutonnet, Magali
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    On the effect of water on the Fischer-Tropsch rate over a Co-based catalyst: The influence of the H2/CO ratio2013Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 214, s. 25-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of water partial pressure on the Fischer-Tropsch (FT) rate of a cobalt catalyst supported on narrow-pore γ-Al2O3 was investigated at industrially relevant process conditions (483 K, 30 bar, pellet size: 53-90 μm). Inlet water partial pressure was varied up to 9 bar by external water vapour addition at different H2/CO molar ratios ranging from 1 to 3. The effect of water was found to be positive on FT-rate independently of the H2/CO ratio, but more significantly at H 2-poor condition. Temperature-programmed hydrogenation (TPH) was used to verify the presence of unreactive carbon species on the catalyst after 22 h on stream at the different conditions with and without exposure to about 9 bar water. A higher temperature feature that could be associated to amorphous polymeric carbon was detected at H2-poor conditions but remained unchanged upon 2 h of water exposure which did not result in a change in the amount of amorphous polymeric carbon detectable by TPH.

  • 178.
    Lualdi, Matteo
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Lögdberg, Sara
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Di Carlo, G.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Boutonnet, Magali
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Venezia, A. M.
    Blekkan, E. A.
    Holmen, A.
    Evidence for diffusion-controlled hydrocarbon selectivities in the fischer-tropsch synthesis over cobalt supported on ordered mesoporous silica2011Inngår i: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 54, nr 16-18, s. 1175-1184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of four cobalt-based catalysts (two of which promoted with ruthenium) supported on SiO2 or SBA-15 were prepared and tested in the Fischer-Tropsch synthesis at industrially relevant process conditions (483 K, 20 bar, H2/CO ratio = 2.1, pellet size: 53-90 μm). The catalysts were characterized by N2-adsorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR), H2-chemisorption and transmission electron microscopy (TEM). Ru as promoter enhanced the activity but not the selectivity to long-chain hydrocarbons ({S}-{C}-{ 5+}). The {{S}}-{{C}}-{5+}} values of the SBA-supported catalysts were very low, especially at low conversion levels (i.e. low water partial pressure), suggesting that CO diffusion limitation increased the H2/CO ratio inside the 1-dimensional (1-D) porous network. A superimposition of the selectivity results on the correlations found in our recent study, derived for Co-based catalysts supported on γ-Al2O3, α-Al2O3 and TiO2 free from diffusion limitations, was made. While the SiO2-supported catalysts with a 3-D porous structure followed the correlations, the SBA-catalysts deviated significantly at low conversions, giving a further indication that the selectivity results of these catalysts were affected by CO diffusion limitations. Hence, it may be concluded that the kinetically significant diffusion distances (i.e. those long enough to cause an intrapore H 2/CO ratio higher than that of the bulk gas phase) are probably much shorter for 1-D porous networks than for conventional 3-D supports. This is explained by a significantly lower effective diffusivity in 1-D porous networks. The potential of using the correlations between non-ASF distributed hydrocarbons and C5+, to give insight on the occurrence of diffusion limitations, was confirmed by superimposing data from the literature that were anticipated to be influenced by CO diffusion limitations.

  • 179.
    Lualdi, Matteo
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Lögdberg, Sara
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Regali, Francesco
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Boutonnet, Magali
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Investigation of mixtures of a Co-based catalyst and a Cu-based catalyst for the fischer-tropsch synthesis with Bio-Syngas: The importance of indigenous water2011Inngår i: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 54, nr 13-15, s. 977-985Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of different mechanical mixtures of a narrow-pore Co/γ-Al2O3 catalyst and a Cu-based WGScatalyst has been investigated in the low-temperature Fischer-Tropsch synthesis (483 K, 20 bar) with a model bio-syngas (H2/CO = 1.0) in a fixed-bed reactor. The higher the fraction of WGS-catalyst in the mixture, the lower is the Co-catalyst-time yield to hydrocarbons. This is ascribed to a strong positive kinetic effect of water on the Fischer-Tropsch rate of the Co-catalyst, showing the importance of the indigenously produced water, especially in fixed-bed reactors where the partial pressure of water is zero at the reactor inlet. A preliminary kinetic modeling suggests that the reaction order in PH2O is 0.3 for the Co/γ-Al2O3 catalyst in the range of the studied reactor-average partial pressures of water (i.e., 0.04-1.2 bar).

  • 180.
    Mahmoudzadeh, Batoul
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Modeling Solute Transport in Fractured Rocks-Role of Heterogeneity, Stagnant Water Zone and Decay Chain2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A model is developed to describe solute transport and retention in fractured rocks. It accounts for the fact that solutes not only can diffuse directly from the flowing channel into the adjacent rock matrix composed of different geological layers but can also at first diffuse into the stagnant water zone occupied in part of the fracture and then from there into the rock matrix adjacent to it. Moreover, the effect of radioactive decay-chain has also been studied in the presence of matrix comprising different geological layers. In spite of the complexities of the system, the analytical solution obtained for the Laplace-transformed concentration at the outlet of the flowing channel can conveniently be transformed back to the time domainby use of e.g. De Hoog algorithm. This allows one to readily include it into a fracture network modelorachannelnetwork model to predictnuclide transport through channels in heterogeneous fracturedmedia consisting of an arbitrary number of rock units withpiecewise constant properties. Simulations made in this study indicate that, in addition to the intact wall rock adjacent to the flowing channel, the stagnant water zone and the rock matrix adjacent to it may also lead to a considerable retardation of solute in cases with a narrow channel. The results further suggest that it is necessary to account for decay-chain and also rock matrix comprising at least two different geological layers in safety and performance assessment of the repositories for spent nuclear fuel. The altered zone may cause a great decrease of the nuclide concentration at the outlet of the flowing channel. The radionuclide decay, when accounted for, will drastically decrease the concentration of nuclides, while neglecting radioactive ingrowth would underestimate the concentration of daughter nuclides.

  • 181.
    Mahmoudzadeh, Batoul
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Liu, Longcheng
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Solute transport in a single fracture involving an arbitrary length decay chain with rock matrix comprising different geological layers2014Inngår i: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 164, s. 59-71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A model is developed to describe solute transport and retention in fractured rocks. It accounts for advection along the fracture, molecular diffusion from the fracture to the rock matrix composed of several geological layers, adsorption on the fracture surface, adsorption in the rock matrix layers and radioactive decay-chains. The analytical solution, obtained for the Laplace-transformed concentration at the outlet of the flowing channel, can conveniently be transformed back to the time domain by the use of the de Hoog algorithm. This allows one to readily include it into a fracture network model or a channel network model to predict nuclide transport through channels in heterogeneous fractured media consisting of an arbitrary number of rock units with piecewise constant properties. More importantly, the simulations made in this study recommend that it is necessary to account for decay-chains and also rock matrix comprising at least two different geological layers, if justified, in safety and performance assessment of the repositories for spent nuclear fuel.

  • 182.
    Mahmoudzadeh, Batoul
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Liu, Longcheng
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Solute transport in fractured rocks with stagnant water zone and rock matrix composed of different geological layers-Model development and simulations2013Inngår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, nr 3, s. 1709-1727Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A model is developed to describe solute transport and retention in fractured rocks. It accounts for the fact that solutes can not only diffuse directly from the flowing channel into the adjacent rock matrix composed of different geological layers but also at first diffuse into the stagnant water zone occupied in part of the fracture and then from there into the rock matrix adjacent to it. In spite of the complexities of the system, it is shown that the analytical solution to the Laplace-transformed concentration at the outlet of the flowing channel is a product of two exponential functions, and it can be easily extended to describe solute transport through channels in heterogeneous fractured media consisting of an arbitrary number of rock units with piecewise constant geological properties. More importantly, by numerical inversion of the Laplace-transformed solution, the simulations made in this study help to gain insights into the relative significance and the different contributions of the rock matrix and the stagnant water zone in retarding solute transport in fractured rocks. It is found that, in addition to the intact wall rock adjacent to the flowing channel, the stagnant water zone and the rock matrix adjacent to it may also lead to a considerable retardation of solute in cases with a narrow channel.

  • 183.
    Malmström Jonsson, Eva E.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Bruce, Carl
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Carlsson, Linn
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Larsson, Emma
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Fogelström, Linda
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Modification of cellulose substrates using polymers obtained by controlled radical polymerization: Covalent grafting or physiosorption of polyelectrolytes2014Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Artikkel i tidsskrift (Annet vitenskapelig)
  • 184. Matindoust, Samaneh
    et al.
    Farzi, Ali
    Nejad, Majid Baghaei
    Abadi, Mohammad Hadi Shahrokh
    Zou, Zhuo
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zheng, Li-Rong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektronik, Integrerade komponenter och kretsar.
    Ammonia gas sensor based on flexible polyaniline films for rapid detection of spoilage in protein-rich foods2017Inngår i: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 28, nr 11, s. 7760-7768Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work details the fabrication and performance of a sensor for ammonia gas, based on conducting polymer. The fabrication procedure consists following steps; polyaniline synthesis via oxidative polymerization technique, then a sensitive polyaniline film was deposited on a printed circuit board and finally, polyaniline microdevice were assembled on an interdigitated electrode arrays to fabricate the sensor for amomonia gas detection. Response time of this chemiresistive devices and humidity impact were examined for NH3 sensitivity and compared with commercial gas sensors (Taguchi Model 826). Data export from sensor to the computer was carried out via data logger model ADC-24 and analyzed using SPSS software. The sensor was found to have a rapid (t = 40 s) and stable linear response to ammonia gas in the concentration range of interest (50-150 ppm) under room temperature operation condition. It was reviled also reliable results to the variation of environment humidity. Power consumption, sensitivity, dimension, flexibility and fabrication cost were used as most important parameters to compare the new polymer based device with those of other similar works and the results showed that small size, low cost, flexibility, low power consumption and high sensitivity are from the benefits of this innovative device. In real-time application conditions flexible polyaniline based gas sensor with polyimide substrate in thickness 0.25 mm exhibits relatively good performance and accurate evaluation of food spoilage.

  • 185. Mattsson, Tuve
    et al.
    Richards, Tobias
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    The separation of green liquor sludge: A comparison between liquors produced in a gasifier and a recovery boiler2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Green liquor is produced as when chemicals are recovered in the kraft pulp process. The industrial formed green liquor contains a solid, non-solvable phase, called green liquor dregs and are removed either by filtration, or by sedimentation. This work compares separation properties of green liquor produced in a gasifier unit with green liquor produced in a recovery boiler. The two types of green liquors were found to have almost similar separation properties with respect to both sedimentation and filtration. For filtration, the average specific filtration resistance was about 1012 m/kg at 1 bar filtration pressure.

  • 186. Mealey, Donal
    et al.
    Svärd, Michael
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära. University of Limerick, Castletroy, Ireland .
    Rasmuson, Åke C.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära. University of Limerick, Castletroy, Ireland .
    Thermodynamics of risperidone and solubility in pure organic solvents2014Inngår i: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 375, s. 73-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The solid-liquid solubility of the thermodynamically stable form I of the drug risperidone has been determined by a gravimetric method in nine pure organic solvents in the temperature range 278.15-323.15 K. The melting temperature and associated enthalpy of fusion of risperidone form I has been determined by differential scanning calorimetry (DSC) to be 442.38 K and 43.94 kJ mol(-1), respectively. The heat capacity of the solid form I and the melt have been determined over a range of temperatures by temperature-modulated DSC, and extrapolated data has been used to calculate the Gibbs energy, enthalpy and entropy of fusion from ambient temperature up to the melting point. The ideal solubility within a Raoult's law framework is obtained from the Gibbs energy of fusion, and the solution activity coefficient at equilibrium in the nine solvents quantified. Solutions in all solvents exhibit positive deviation from Raoult's law, with the highest solubility (closest to ideality) in toluene, an aprotic apolar solvent. The solubility curves plotted in a van't Hoff graph show non-linear behaviour and are well-approximated by a second order polynomial.

  • 187.
    Melios, Christos
    et al.
    Natl Phys Lab, England; Univ Surrey, England.
    Panchal, Vishal
    Natl Phys Lab, England.
    Edmonds, Kieran
    Royal Holloway Univ London, England.
    Lartsev, Arseniy
    Chalmers Univ Technol, Sweden.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Kazakoya, Olga
    Natl Phys Lab, England.
    Detection of Ultralow Concentration NO2 in Complex Environment Using Epitaxial Graphene Sensors2018Inngår i: ACS SENSORS, ISSN 2379-3694, Vol. 3, nr 9, s. 1666-1674Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate proof-of-concept graphene (a) sensors for environmental monitoring of ultralow concentration NO2 in complex environments. Robust detection in a wide range of NO2 concentrations, 10-154 ppb, was achieved, highlighting the great potential for graphene-based NO2 sensors, with applications in environmental pollution monitoring, portable monitors, automotive and mobile sensors for a global real-time monitoring network. The measurements were performed in a complex environment, combining NO2/synthetic air/water vapor, traces of other contaminants, and variable temperature in an attempt to fully replicate the environmental conditions of a working sensor. It is shown that the performance of the graphene-based sensor can be affected by coadsorption of NO2 and water on the surface at low temperatures (amp;lt;= 70 degrees C). However, the sensitivity to NO2 increases significantly when the sensor operates at 150 degrees C and the cross-selectivity to water, sulfur dioxide, and carbon monoxide is minimized. Additionally, it is demonstrated that single-layer graphene exhibits two times higher carrier concentration response upon exposure to NO2 than bilayer graphene.

  • 188.
    Minkova, V.
    et al.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Marinov, S. P.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Zanzi, Rolando
    KTH, Tidigare Institutioner, Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Bjornbom, E.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Stefanova, M.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Lakov, L.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Thermochemical treatment of biomass in a flow of steam or in a mixture of steam and carbon dioxide2000Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 62, nr 1, s. 45-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simultaneous pyrolysis and gasification of biomass samples of different origin is performed in a flow of steam or in a mixture of steam and carbon dioxide. Wastes from birch wood, olive stones, bagasse, and pellets from straw and Miscanthus are used as feedstock. The raw materials are heated with 10 degrees C/min to 750 degrees C at atmospheric pressure and kept for a period of 2 h at this temperature, Laboratory experimental equipment with a horizontal rotating stainless steel reactor is used. The oxygen-containing functional groups in the solid products (-COOH, =CO and -OH) are determined using the method of Boehm. The results are compared with those obtained in treatment in inert atmosphere as well as with those obtained in a stationary reactor. The rotating pyrolysis reactor seems suitable for production of energy-rich gaseous products and activated carbons.

  • 189.
    Minkova, V.
    et al.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Razvigorova, M.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Bjornbom, E.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Zanzi, Rolando
    KTH, Tidigare Institutioner, Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Petrov, N.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Effect of water vapour and biomass nature on the yield and quality of the pyrolysis products from biomass2001Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 70, nr 1, s. 53-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Slow pyrolysis/activation of biomass in a flow of steam is studied in laboratory equipment supplied with a fixed bed reactor. Forestry and agricultural residues of different origin are selected as raw materials (birch wood, olive stones, bagasse, pelletised straw and miscanthus). The final pyrolysis temperature is varied in the range 700-800 degreesC and the duration of the activation is 1 or 2 h. The effect of both the nature of the investigated biomass samples and the presence of water vapour on the quality of the pyrolysis products is in the focus of interest of this work. Column chromatography is used to characterize the liquid products. The surface area and the acid-base neutralization capacity of the solid products are determined by the adsorption capacity towards iodine and reactions with EtONa and HCl. The results are compared with those obtained in pyrolysis in inert atmosphere of nitrogen. It is shown that the presence of steam has strong effect on the yield and properties of the products. Significant part of the liquid product is found dissolved in the water phase obtained after condensation of the volatiles. The solid products obtained in the presence of steam have the properties of activated carbons.

  • 190.
    Mitraka, Evangelia
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Conducting Polymer Electrodes for Oxygen Reduction Reaction2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Both the pollution level of the environment and the increasing energy demands have stimulated intense research on the development of low-cost environmentally-friendly energy conversion and storage systems with high efficiency, such as metal-air batteries and fuel cells.

    One of the most essential parts of both fuel cells and metal–air batteries is the air-electrode which is responsible for the reduction of O2. The air-electrode can use O2 from air facilitating the layout of the device; however, the process taking place on it is significantly complex. Currently, platinum (Pt) is the benchmark for air-electrodes in such technologies, although it is expensive and exhibits other important disadvantages which diminish the fuel cell performance. Therefore, extensive research has been devoted to reduce the amount of Pt used in air-electrodes and to develop a noble metal-free version of these electrodes.

    The area of printed electronics could facilitate the development of low-cost electrodes produced in high volume for such applications. Conducting polymers are attractive materials for this technology because they may combine several desired properties, like electronic conduction, ionic conduction and catalysis of electrochemical reactions.

    Among other conducting polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) emerged as an alternative cathode catalyst material to Pt, due to its ability to effectively catalyze the oxygen reduction reaction (ORR), while it also exhibits high electrical and ionic conductivity.

    The focus of this thesis is to study the electrocatalytic activity and mechanism of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) when employed as an airelectrode in energy storage devices, such as fuel cells and metal-air batteries. Although PEDOT is extensively studied during the last decade as an air-electrode for fuel cell and metal-air batteries, vital pieces of the catalytic mechanism that PEDOT follows remain unknown, namely: (i) the sites of PEDOT on which O2 interacts and (ii) the intermediate species which are formed during the ORR. The content of this thesis tackles these topics, both from experimental and theoretical point of view. Moreover, it investigates the use of PEDOT as an active electrocatalyst in a polymer exchange membrane (PEM) fuel cell, by embedding the polymer in a cellulose matrix, aiming to fabricate a gas diffusion electrode for the ORR side of the device. Finally, the goal of the thesis surpasses the limit of the p-doped PEDOT and undertakes the evaluation of a n-type conjugated polymer of high electron affinity as a cathode in reduction processes.  

  • 191.
    Mogensen, Ronnie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    PTMC: A polycarbonate candidate for polymer electrolytes in sodium batteries?: A characterisation of the PTMC–NaFSI system2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The poly(trimethylene carbonate)–sodium bis(fluorosulfonyl)imide system has been

    investigated as polymer electrolytes for sodium batteries. The properties of

    poly(trimethylene carbonate) with salt concentrations ranging from 8.7wt% to 67wt%

    have been measured by DSC, FTIR, and EIS. Half-cells based on both high-salt and

    low-salt electrolytes have been tested in order to determine their performance in a

    realistic environment. The tests reveal two distinct regions in salt concentration and

    the best-performing electrolytes show a conductivity of 50 μS/cm at 25 °C and 1mS/

    cm at 100 °C. The report presents cell data from sodium–prussian blue half-cells

    with only 10% capacity fade after 80 cycles at 60 °C and additional tests of high-salt

    cells capable of cycling at reduced temperature with good rate capability.

  • 192.
    Mohsenzadeh, Abas
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Richards, Tobias
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Bolton, Kim
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    DFT study of the water gas shift reaction on Ni (111), Ni (100) and Ni (110) surfaces2016Inngår i: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 644, s. 53-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Density functional theory (DFT) calculations were used to study the water gas shift (WGS) reaction on Ni(111), Ni(100) and Ni(110) surfaces. The adsorption energy for ten species involved in thereaction together with activation barriers and reaction energies for the nine most important elementary steps were determined using the same model and DFT methods. The results reveal that these energies are sensitive to the surface structure. In spite of this, the WGS reaction occurs mainly via the direct (also referred to as redox) pathway with the CO + O → CO2 reaction as the rate determining step on all three surfaces. The activation barrier obtained for this rate limiting step decreases in the order Ni(110) > Ni(111) > Ni(100). Therefore, if O species are present on the surfaces then the WGSreaction is fastest on the Ni(100) surface. However, the barrier for desorption of H2O (which is the source of the O species) is lower than its dissociation reaction on the Ni(111) and Ni(100) surfaces, but not on the Ni(110) surface. Hence, at low H2O(g) pressures, the direct pathway on the Ni(110) surface will dominate and will be the rate limiting step. The calculations also show that the reason that the WGS reaction does not primarily occur via the formate pathway is that this species is a stable intermediate on all surfaces. The reactions studied here support the Brønsted-Evans-Polanyi (BEP) principles with an R2 value of 0.99. © 2015 Elsevier B.V. All rights reserved.

  • 193. Montes, V.
    et al.
    Boutonnet, M.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Lualdi, Matteo
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Marinas, A.
    Marinas, J. M.
    Urbano, F. J.
    Mora, M.
    Preparation and characterization of Pt-modified Co-based catalysts through the microemulsion technique: Preliminary results on the Fischer-Tropsch synthesis2014Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 223, s. 66-75Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of the addition of small amounts of platinum (0.1-0.25% wt) to cobalt-based systems on Fischer-Tropsch synthesis was investigated. The solids were synthesized through microemulsion technique using TiO2 as the support. The best catalytic performance was achieved using Synperonic 13/6.5 as the surfactant. In all cases, the presence of platinum led to an increase in CO conversion which could be ascribed to the promotion of cobalt reducibility as evidenced by XPS. Moreover, the simultaneous reduction of cobalt and platinum precursors during synthetic procedure (ME1) was preferable to the consecutive one (ME2) probably as a result of a better Co-Pt interaction in the former case, as evidenced by TPR. TPR, Raman and XPS data also suggested that not only the presence of Co-0 but also the appearance of Co-TiO2 interactions favor the catalytic performance and that in general those interactions are stronger for ME1 solids.

  • 194. Montes, V.
    et al.
    Boutonnet, Magali
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Marinas, A.
    Marinas, J. M.
    Urbano, F. J.
    Selective transformation of glycerol into 1,2-propanediol on several Pt/ZnO solids: Further insight into the role and origin of catalyst acidity2015Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 257, s. 246-258Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microemulsion technique allowed us to synthesize different ZnO solids with similar particle sizes and textural properties. Platinum was subsequently incorporated by deposition-precipitation and impregnation methods and solids tested for glycerol selective transformation into 1,2-PDO. Incorporation of platinum led to the creation of new (mainly Lewis) acid sites. A good correlation between conversion and acidity of Pt/ZnO solids was obtained. Interestingly, despite exhibiting some acidity, supports alone were inactive in the process which evidenced the role of the metal in dehydration of glycerol into acetol. Furthermore, as the reaction proceeded some chlorine coming from the precursor (H2PtCl6) was leached which led to the disappearance of the strongest acid sites, associated to side reactions (catalytic cracking) thus resulting in an increase in selectivity to 1,2-PDO. Eventual formation of Pt-Zn alloy upon reduction of the systems at ca. 400 degrees C was beneficial to 1,2-PDO selectivity.

  • 195. Montes, V.
    et al.
    Checa, M.
    Marinas, A.
    Boutonnet, Magali
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Marinas, J. M.
    Urbano, F. J.
    Järås, Sven
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Pinel, C.
    Synthesis of different ZnO-supported metal systems through microemulsion technique and application to catalytic transformation of glycerol to acetol and 1,2-propanediol2014Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 223, s. 129-137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Different systems consisting of diverse metals (Au, Pt, Pd, Rh) supported on ZnO (5% by weight) were synthesized through the microemulsion technique (ME) and tested for glycerol hydrogenolysis, the main products being hydroxyacetone (acetol) and 1,2-propanediol (1,2-PDO). The solids synthesized using sodium borohydride as the reducing agent (B series) had smaller particle sizes as compared to the use of hydrazine (H series) which, in turn, resulted in a better catalytic performance. This synthetic method allowed us to obtain similar metal particle sizes (2-4 nm) for Pt, Pd and Rh solids in B series, whereas average gold metal particle was higher (> 8 nm) which probably accounts for Au-containing systems being inactive under our experimental conditions. Reactivity order followed the sequence Rh > Pt > Pd. A comparison of the systems synthesized in the present paper through ME technique with those obtained in a previous work through the deposition-precipitation process revealed a higher activity and selectivity to acetol for the former solids which could be related to the presence of surfactant. Moreover, results suggested that metal sites could participate not only in hydrogenation of acetol to 1,2-propanediol but also in the previous dehydration step of glycerol to acetol.

  • 196.
    Moro, Fabrizio
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten. Univ Nottingham, England.
    Bhuiyan, Mahabub A.
    Univ Nottingham, England.
    Kudrynskyi, Zakhar R.
    Univ Nottingham, England.
    Puttock, Robert
    Natl Phys Lab, England.
    Kazakova, Olga
    Natl Phys Lab, England.
    Makarovsky, Oleg
    Univ Nottingham, England.
    Fay, Michael W.
    Univ Nottingham, England.
    Parmenter, Christopher
    Univ Nottingham, England.
    Kovalyuk, Zakhar D.
    Natl Acad Sci Ukraine, Ukraine.
    Fielding, Alistar J.
    Sch Pharm and Biomol Sci, England.
    Kern, Michal
    Univ Stuttgart, Germany; Univ Stuttgart, Germany.
    van Slageren, Joris
    Univ Stuttgart, Germany; Univ Stuttgart, Germany.
    Patane, Amalia
    Univ Nottingham, England.
    Room Temperature Uniaxial Magnetic Anisotropy Induced By Fe-Islands in the InSe Semiconductor Van Der Waals Crystal2018Inngår i: ADVANCED SCIENCE, ISSN 2198-3844, Vol. 5, nr 7, artikkel-id 1800257Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moores law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.

  • 197.
    Mussa, Abdilbari Shifa
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Klett, Matilda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Wreland Lindström, Rakel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Effects of external pressure on the performance and ageing of single-layer lithium-ion pouch cells2018Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 385, s. 18-26Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of external compression on the performance and ageing of NMC(1/3)/Graphite single-layer Li-ion pouch cells are investigated using a spring-loaded fixture. The influence of pressure (0.66, 0.99, 1.32, and 1.98 MPa) on impedance is characterized in fresh cells that are subsequently cycled at the given pressure levels. The aged cells are analyzed for capacity fade and impedance rise at the cell and electrode level. The effect of pressure distribution that may occur in large-format cells or in a battery pack is simulated using parallel connected cells. The results show that the kinetic and mass transport resistance increases with pressure in a fresh cell. An optimum pressure around 1.3 MPa is shown to be beneficial to reduce cyclable-lithium loss during cycling. The minor active mass losses observed in the electrodes are independent of the ageing pressure, whereas ageing pressure affects the charge transfer resistance of both NMC and graphite electrodes and the ohmic resistance of the cell. Pressure distribution induces current distribution but the enhanced current throughput at lower pressures cell does not accelerate its ageing. Conclusions from this work can explain some of the discrepancies in non-uniform ageing reported in the literature and indicate coupling between electrochemistry and mechanics.

  • 198.
    Ngo, Carolin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    In Vitro Starch Digestion for Analysis of Healthy Carbohydrates2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The health impact of carbohydrates is often debated in questions regarding nutrition and health. One reason is that intake of carbohydrates affect the blood glucose level to different extent depending on the characteristics of the carbohydrate. Starch is the most common carbohydrate and it can be categorized as rapidly digested starch (RDS), slowly digested starch (SDS) and resistant starch (RS) where the speed parameter refers to how easily enzymes hydrolyze the starch is and thus how fast the blood glucose level is affected.

    However, RS does not affect the blood glucose level but instead becomes substrate for microbial fermentation of the gut microbiota. Long term consumption of resistant starch decreases the risk of intestinal diseases. The aim of this project was therefore to investigate different in vitro methods for determination of RS content in samples. The impact which particle size and extrusion have on the amount of RS were investigated since the factors can increase or decrease the amount of RS.

    Sorghum and cowpea were of interest to analyze since the crops are important nutrient sources in both Africa and Asia. Two methods were investigated for determination of RS content where the method developed by Megazyme International Ireland Ltd. was more stable than the method developed by Goñi et al. Modifications of the Megazyme method were performed in order to obtain more reliable values which was achieved when enzymes from Sigma-Aldrich were used. Samples of sorghum of the particle sizes 125 µm and 250 µm resulted in values ranging between 11.44 – 11.94 g RS/100 g sample and 8.49 – 9.02 g RS/100 g sample after extrusion was performed. Samples of the larger particle size resulted in lower amount of RS, most likely due to starch-protein associations. Cowpea resulted in 11.05 g RS/100 g sample and 9.20 g RS/100 g sample before and after extrusion.

    Determination of the amylose and amylopectin ratio showed that sorghum contained 53.3 – 59.3 % (w/w) amylose and cowpea 53.2 % (w/w) amylose. A ratio favoring amylose also favors the formation of RS. However, the particle size has larger impact on the RS content than the amylose content and sorghum of particle size 125 µm was shown to be the healthiest regarding amount of RS. Cowpea showed the lowest amount of amylose yet the highest amount of RS among the extrudates and the lowest set back value of -0.5 which leads to an assumption towards unstable methods.

    Further development of the methods should be carried out in forms of modifications. Optimization of treatments regarding sorghum of particle size 125 µm should be continued in order to obtain even higher RS content.

  • 199.
    Niklasson, Lovisa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Characterization of the gas composition inside NiMH batteries during charge using GC-MS2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of the project was to develop a method to measure and studythe degree of activation of the negative electrode (MH) in a NiMH battery.This was done by characterization of the gases produced during charge of a battery – O2 and H2 – using a Gas Chromatograph. The current applied in the very first charge of the battery was varied in order to examine how this affects the gas evolution. In the developed method, batteries were charged to 8Ah with 9A, after which a gas sample was taken and analyzed with Gas Chromatography. An additional goal was to use the method to examine the difference in activation between virgin and recycled negative electrode material. A module charged stepwise with 0.07C followed by 0.2C had the lowest share of H2 after two cycles, indicated best activation. However, a higher amount of H2 in the beginning of the activation process could possibly enhance the degree of activation during the following cycles. The method indicated that the module with recycled MH was better activated than the virgin MH. To improve the technique, repeated measurements to get better statistics should be done. Gas samples should be taken at dV/dt=0 in order to take samples at same SoC. The charge current should be adjusted so that the same C rate is always used. This would make the results easier to interpret.

  • 200.
    Nilsson, Oskar
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Radiation induced corrosion of steel2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this thesis was to investigate the influence of aqueous radiation induced oxidants on stainless steel. This was done by exposing the steel to both radiation and chemically added oxidants under ambient conditions, i.e. in and near room temperature. When water is exposed to radiation several oxidizing species are formed, including hydrogen peroxide, which have been known to increase the risk for corrosion of other materials. Stainless steel is used in many parts in a nuclear power plant, and the results from this thesis could be useful when elucidating whether the steel is an appropriate material to use for these applications.

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