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  • 251. Shafiu, S.
    et al.
    Baykal, A.
    Sozeri, H.
    Toprak, Muhammet
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM. Yildirim Beyazit Univ, Dept Mat Sci & Engn, Ulus Ankara, Turkey.
    Triethanolamine Assisted Hydrothermal Synthesis of Superparamagnetic Co3O4 Nanoparticles and Their Characterizations2014Inngår i: Journal of Superconductivity and Novel Magnetism, ISSN 1557-1939, E-ISSN 1557-1947, Vol. 27, nr 9, s. 2117-2122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present, for the first time, on a facile route for the fabrication of highly crystalline Co3O4 nanoparticles using trietanolamine (TEA) assisted hydrothermal synthesis route and single precursor. Synthesized material has been evaluated for its structural, morphological and magnetic properties using x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The material has been identified as highly crystalline Co3O4, with superparamagnetic character due to size confinement. Estimated particle size from SEM is about 10 nm, which is close to the magnetic domain size (estimated from VSM as 8.4 +/- 1.7 nm) and the crystallite size (estimated from XRD as 11 pm 4 nm), which reveal nearly single crystalline character of Co3O4 nanoparticles. The suggested route is facile, which provides a good size control over the nanoparticles, and can be used for the fabrication of other ceramic materials.

  • 252.
    Shahid, Robina
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Gorlov, Mikhail
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    El-Sayed, Ramy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Toprak, Muhammet S.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Sugunan, Abhilash
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Kloo, Lars
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Microwave assisted synthesis of ZnS quantum dots using ionic liquids2012Inngår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 89, s. 316-319Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work we report results from microwave (MW) assisted synthesis of highly crystalline ZnS quantum dots (QDs) using ionic liquid (ILs) as MW absorbing medium. Two types of ionic liquids, imidazolium and phosphonium based, were used. The QDs are less than 5 nm in size and of wurtzite ZnS type, as characterized by high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) pattern. The optical properties were investigated by UV-vis absorption and show a blue shift in absorption as compared to bulk wurtzite ZnS due to quantum confinement effects. The photoluminescence (PL) spectra of the QDs show different trap state emissions.

  • 253.
    Shahkarami, Pirouz
    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.
    The effect of stagnant water zones on retarding radionuclide transport in fractured rocks: An extension to the Channel Network Model2016Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 540, s. 1122-1135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An essential task of performance assessment of radioactive waste repositories is to predict radionuclide release into the environment. For such a quantitative assessment, the Channel Network Model and the corresponding computer program, CHAN3D, have been used to simulate radionuclide transport in crystalline bedrocks. Recent studies suggest, however, that the model may tend to underestimate the rock retarding capability, because it ignores the presence of stagnant water zones, STWZs, situated in the fracture plane. Once considered, the STWZ can provide additional surface area over which radionuclides diffuse into the rock matrix and thereby contribute to their retardation.

    The main objective of this paper is to extend the Channel Network Model and its computer implementation to account for diffusion into STWZs and their adjacent rock matrices.

    In the first part of the paper, the overall impact of STWZs in retarding radionuclide transport is investigated through a deterministic calculation of far-field releases at Forsmark, Sweden. Over the time-scale of the repository safety assessments, radionuclide breakthrough curves are calculated for increasing STWZ width. It is shown that the presence of STWZs enhances the retardation of most long-lived radionuclides except for 36Cl and 129I.

    The rest of the paper is devoted to the probabilistic calculation of radionuclide transport in fractured rocks. The model that is developed for transport through a single channel is embedded into the Channel Network Model and new computer codes are provided for the CHAN3D. The program is used to (I) simulate the tracer test experiment performed at Äspö HRL, STT-1 and (II) investigate the short- and long-term effect of diffusion into STWZs. The required data for the model are obtained from detailed hydraulic tests in boreholes intersecting the rock mass where the tracer tests were made.

    The simulation results fairly well predict the release of the sorbing tracer 137Cs. It is found that over the short time-scale of the tracer experiment, the effect of diffusion into STWZs is not as pronounced as that of matrix diffusion directly from the flow channel, and the latter remains the main retarding mechanism. Predictions for longer time-scale, tens of years and more, show that the effect of STWZs becomes strong and tends to increase with transport time. It is shown that over the long times of interest for safety assessment of radioactive waste repositories, STWZs can substantially contribute to radionuclide retardation, though for the short time-scales the impact is not very strong and is not expected to affect the results of short-term field experiments.

  • 254.
    Shahkarami, Pirouz
    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.
    Analytical solution for N-member decay chain transport in fracture in rock2013Inngår i: Rock Characterisation, Modelling and Engineering Design Methods - Proceedings of the 3rd ISRM SINOROCK 2013 Symposium, Taylor & Francis Group, 2013, s. 323-328Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A model is developed to describe the transport of an N-member radionuclide decay chain along a discrete fracture situated in a porous matrix. An analytical solution is presented and a series of simulations are performed to study the relative significance of diffusion process into rock matrix, stagnant water, chain decay and hydrodynamic dispersion. The results show that a simplified model that ignores the effect of stagnant water zone can lead to significant error in the estimated time of arrival and peak value of the nuclides. The results demonstrate that for a two-member decay chain, neglecting the parent and modeling its daughter as a single species can result in significant overestimation of peak value of the nuclide. Moreover, it is found that as the dispersion increases, the arrival time and peak time of daughter decrease, while the peak value increases.

  • 255.
    Shahkarami, Pirouz
    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.
    Radionuclide migration through fractured rock for arbitrary-length decay chain: Analytical solution and global sensitivity analysis2015Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 520, s. 448-460Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presents an analytical approach to simulate nuclide migration through a channel in a fracture accounting for an arbitrary-length decay chain. The nuclides are retarded as they diffuse in the porous rock matrix and stagnant zones in the fracture. The Laplace transform and similarity transform techniques are applied to solve the model. The analytical solution to the nuclide concentrations at the fracture outlet is governed by nine parameters representing different mechanisms acting on nuclide transport through a fracture, including diffusion into the rock matrices, diffusion into the stagnant water zone, chain decay and hydrodynamic dispersion. Furthermore, to assess how sensitive the results are to parameter uncertainties, the Sobol method is applied in variance-based global sensitivity analyses of the model output. The Sobol indices show how uncertainty in the model output is apportioned to the uncertainty in the model input. This method takes into account both direct effects and interaction effects between input parameters. The simulation results suggest that in the case of pulse injections, ignoring the effect of a stagnant water zone can lead to significant errors in the time of first arrival and the peak value of the nuclides. Likewise, neglecting the parent and modeling its daughter as a single stable species can result in a significant overestimation of the peak value of the daughter nuclide. It is also found that as the dispersion increases, the early arrival time and the peak time of the daughter decrease while the peak value increases. More importantly, the global sensitivity analysis reveals that for time periods greater than a few thousand years, the uncertainty of the model output is more sensitive to the values of the individual parameters than to the interaction between them. Moreover, if one tries to evaluate the true values of the input parameters at the same cost and effort, the determination of priorities should follow a certain sequence.

  • 256.
    Shahkarami, Pirouz
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Liu, Longcheng
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Channel Network Concept — an Integrated Approach to Visualize Solute Transport in Fractured RocksManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The advection-dispersion equation, ADE, has commonly been used to visualize solute transport in fractured rock. However, there is one key question that has to be addressed before the mathematical form of the so-called Fickian dispersion that underlies the ADE takes on physical meaning in fractures. What is the travel distance, or travel time, required before the Fickian condition is met and the ADE becomes physically reasonable? A simple theory is presented in this study to address this question in tapered channels. It is shown that spreading of solute under forced-gradient flow conditions is mostly dominated by advective mechanisms, though the ADE might be valid in the channels under natural flow conditions. This implies that the use of the ADE and macro dispersion coefficient might be misleading when applied to interpret field tracer experiment results. Furthermore, several concerns are raised in this paper with regard to utilizing the concept of field-scale matrix diffusion coefficient in fractured rocks. The concerns are mainly directed toward the uncertainties and potential bias involved in finding the continuum model parameters.

    In light of the findings of this study and empirical evidences, it is suggested that it is feasible and more realistic to describe flow and solute transport in fractured rocks as taking place in three-dimensional networks of channels, as embodied in the channel network concept, CN-concept. It is argued that this conceptualization provides a convenient framework to capture the impacts of spatial heterogeneities in fractured rocks and can accommodate the physical mechanisms underlying the behavior of solute transport in such porous media. All these issues are discussed in this paper in relation to analyzing and predicting actual tracer tests in fractured crystalline rocks.

  • 257.
    Sharifi, Tiva
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Kwong, Wai Ling
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Berends, Hans-Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Larsen, Christian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Messinger, Johannes
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Maghemite nanorods anchored on a 3D nitrogen-doped carbon nanotubes substrate as scalable direct electrode for water oxidation2016Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 41, nr 1, s. 69-78Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A hybrid catalyst 3D electrode for electrochemical water oxidation to molecular oxygen is presented. The electrode comprises needle shaped maghemite nanorods firmly anchored to nitrogen doped carbon nanotubes, which in turn are grown on a conducting carbon paper that acts as efficient current collector. In 0.1 M KOH this hybrid electrode reaches a current density of 1 mA/cm(2) (geometric surface) at an overpotential of 362 mV performing high chronoamperometric stability. The electrochemical attributes point toward efficient catalytic processes at the surface of the maghemite nanorods, and demonstrate a very high surface area of the 3D electrode, as well as a firm anchoring of each active component enabling an efficient charge transport from the surface of the maghemite rods to the carbon paper current collector. The latter property also explains the good stability of our hybrid electrode compared to transition metal oxides deposited on conducting support such as fluorine doped tin oxide. These results introduce maghemite as efficient, stable and earth abundant oxygen evolution reaction catalyst, and provide insight into key issues for obtaining practical electrodes for oxygen evolution reaction, which are compatible with large scale production processes. 

  • 258. Shen, Hangjia
    et al.
    Gracia-Espino, Eduardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Wang, Le
    Qin, Danfeng
    Gao, Sanshuang
    Mamat, Xamxikamar
    Ren, Wei
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hu, Guangzhi
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Urumqi 830011, Peoples R China.
    Microwave-assisted synthesis of multimetal oxygen-evolving catalysts2017Inngår i: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 81, s. 116-119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxygen evolution reaction (OER) plays a pivotal role in water-splitting. Here, we report a facile method to synthesize multimetal supported on commercial carbon black via a time-saving microwave process. Crystalline FeNi3 nanoparticles homogeneously doped with Mo are formed via a microwave treatment and activated to metal oxyhydroxide in-situ during cyclic voltammetry test with overpotential of only 280 mV at 10 mA cm(-2) for OER in alkaline electrolyte, outperforming RuO2. Our synthesis methodology is a promising alternative for large-scale production, delivering a valuable contribution to catalyst preparation and electrocatalytic water oxidation research.

  • 259.
    Silveira, Jose Luz
    et al.
    Sao Paulo State University (UNESP), Campus Guaratinguetá.
    Braga, Lucia Bollini
    Sao Paulo State University (UNESP), Campus Guaratinguetá.
    Caetano de Souza, Antonio Carlos
    Sao Paulo State University (UNESP), Campus Guaratinguetá.
    Antunes, Julio Santana
    Sao Paulo State University (UNESP), Campus Guaratinguetá.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    The benefits of ethanol use for hydrogen production in urban transportation2009Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 13, nr 9, s. 2525-2534Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to describe the benefits of sugar cane ethanol in Brazil, appointing the productivity of this type of fuel based on hectares of plantation, its carbon dioxide cycle and the contribution to reduce the greenhouse effect. In the following step the uses of ethanol for hydrogen production by steam reforming is analyzed and some comparison with natural gas steam reforming is performed. The sugar cane industry in Brazil, in a near future, in the hydrogen era, could be modified according to our purpose, since besides the production of sugar, and ethylic and anhydric alcohol, Brazilian sugar cane industry will also be able to produce biohydrogen. Fuel cells appear like a promising technology for energy generation. Among several technologies in the present, the PEMFC (proton exchange membrane fuel cell) is the most appropriate for vehicles application, because it combines durability, high power density, high efficiency, good response and it works at relatively low temperatures. Besides that it is easy to turn it on and off and it is able to support present vibration in vehicles. A PEMFC's problem is the need of noble catalysts like platinum. Another problem is that CO needs to be in low concentration, requiring a more clean hydrogen to avoid fuel cell deterioration. One part of this paper was developed in Stockholm, where there are some buses within the CUTE (clean urban transport for Europe) project that has been in operation with FC since January 2004. Another part was developed in Guaratingueta, Brazil. Brazil intends to start up a program of FC buses. As conclusion, this paper shows the economical analysis comparing buses moved by fuel cells using hydrogen by different kinds of production. Electrolyze with wind turbine, natural gas steam reforming and ethanol steam reforming.

  • 260. Silveira, Jose Luz
    et al.
    Martinelli, Valdisley Jose
    Vane, Lucas Fachini
    Freire Junior, Jose Celso
    Zanzi Vigouroux, Rolando A.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Tuna, Celso Eduardo
    Lamas, Wendell de Queiroz
    Silva Paulino, Regina Francielle
    Incorporation of hydrogen production process in a sugar cane industry: Steam reforming of ethanol2014Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 71, nr 1, s. 94-103Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents a technical, ecological and economic analysis of hydrogen production incorporation through ethanol steam reforming at a traditional sugarcane industry (sugar, ethanol). This proposal is reached through a reduction in the amount of fuel (bagasse) that is normally utilized to generate electricity without affecting the sugar and ethanol production processes, however. This surplus bagasse is utilized to produce steam for hydrogen production. In order to achieve this, it is calculated the available bagasse and maximum hydrogen amount and their inputs (hydrated and anhydrous ethanol). Based on the aforementioned, the investment needs are estimated, where the operation and maintenance cost, the operation period, the interest rate, and the annuity are considered. The incorporation of this new process is assessed through a comparison of this innovative plant with the traditional ones.

  • 261.
    Singh, Jagdeep
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Frostell, Björn
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Wennersten, Ronald
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Waste management as a part of a broader systems approach to production and consumption2011Inngår i: Book of Proceedings of the 1st International Conference: WASTES: Solutions, Treatments and Opportunities / [ed] Fernando Castro, Cândida Vilarinho & Joana Carvalho, Guimarães, Portugal: CVR – Centro para a valorização de Resíduos , 2011, s. 124-129Konferansepaper (Fagfellevurdert)
  • 262.
    Sobocinski, Maciej
    et al.
    Microelectronics and Material Physics Laboratories University of Oulu, Finland.
    Khajavizadeh, Lida
    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.
    Lloyd Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten. Microelectronics and Material Physics Laboratories University of Oulu, Finland.
    Juuti, Jari
    Microelectronics and Material Physics Laboratories University of Oulu, Finland.
    Jantunen, Heli
    Microelectronics and Material Physics Laboratories University of Oulu, Finland.
    Performance of LTCC embedded SiC gas sensors2015Inngår i: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 120, s. 253-256Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel approach to encapsulation/packaging of SiC field effect transistor gas sensors for high temperature applications, such as exhaust and fuel gas emissions monitoring, based on direct co-firing of sensor devices and Low-Temperature Co-fired Ceramics (LTCC) has been investigated. Structural (SEM, EDX, XPS), electrical (I/V, C/V) as well as gas sensing characterization of packaged devices has shown that the “one-step” packaging process forms a hermetic package with retained transducer functionality and gas sensing characteristics without the need for any separate die attachment, (wire) bonding, and/or sealing of the package. Long-term stability testing at elevated temperatures of packaged devices has also shown promising results.

  • 263.
    Sotolongo, José Angel
    et al.
    CADETES, CITMA, Guantánamo, Cuba.
    Beatón Soler, Pedro
    CITMA, Santiago de Cuba, Cuba.
    Díaz, Armando
    Oriente University, Cuba.
    Montes de Oca, Sofía
    CADETES, CITMA, Guantánamo, Cuba.
    del Vallel, Yadiris
    CADETES, CITMA, Guantánamo, Cuba.
    García Pavón, Soraya
    CADETES, CITMA, Guantánamo, Cuba.
    Zanzi Vigouroux, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Jatropha Curcas L. as a source for the production of biodiesel: a Cuban Experience2007Inngår i: 15th European Biomass Conference and Exhibition”, 2007, 7-10 May, Berlin, Germany, 2007, s. 2631-2633Konferansepaper (Fagfellevurdert)
  • 264. Sotres, J.
    et al.
    Pettersson, Torbjörn
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindh, L.
    Arnebrant, T.
    NanoWear of Salivary Films vs. Substratum Wettability2012Inngår i: Journal of Dental Research, ISSN 0022-0345, E-ISSN 1544-0591, Vol. 91, nr 10, s. 973-978Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The pellicle serves as a multifunctional protective layer, providing, e.g., lubrication and remineralization and also acting as a diffusion barrier. In addition, since the formation of the pellicle precedes the adhesion of micro-organisms, it is also important as a conditioning film. We present a novel approach to study the influence of the water wettability of solid surfaces on the strength of adsorbed salivary films. It is based on studying the wear resistance of the films with an atomic force microscope operated in the friction force spectroscopy mode. This methodology provides the strength of the films in terms of the forces needed for breaking and removing them. Our results indicate that these forces are highly dependent on the water wettability of the underlying substrata, decreasing with increasing hydrophobicity. Thus, this study provides valuable information for the design of materials exposed in the oral cavity, i.e., materials that will minimize plaque formation and be easy to clean.

  • 265.
    Souza Filho, Pedro
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Zamani, Akram
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Solid Precipitation from Potato Protein Liquor by Ethanol2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The production of starch in European Union (EU 28) was around 10 million tonnes in 2013, 12.6% of them being from potato1. During the potato processing, two main by-products which have high Biological Oxygen Demand (BOD) are formed, i.e. potato pulp (PP) and potato liquor (PL)2. Proteins can be partially recovered from PL, resulting in a concentrated residual material known as potato protein liquor (PoPL)2,3. The use of PoPL has been investigated to cultivate fungal4 and yeast3 biomass, and produce enzymes2. However, presence of nitrogen and phosphate containing materials as well as suspended solids at high concentrations4 limits its application in bioprocesses. The present study was proposed to investigate the precipitation of components from PoPL by ethanol in order to get an easily fermentable solution. PoPL from Lyckeby Starch AB was mixed with different amounts of ethanol and centrifuged at 3000 g for 5 min. The liquid obtained was put under a fume hood for 48 h at room temperature for ethanol evaporation. All the samples had their volumes adjusted to the same value using distilled water. The precipitate was dried at 105 °C. All experiments were done in duplicate. The precipitation of solids improved almost 500% for a mixture of equal volumes of PoPL and ethanol compared to PoPL without ethanol addition. The protein and ash contents of the precipitate were respectively higher than 245 g/kg and 420 g/kg in all the cases, making it eligible for production of fertilizer or animal feed. Most of the analysed sugars (glucose, fructose, and sucrose) stayed in the liquid phase. Ethanol concentration in the liquid phase remained close to initial value after the 48-hour evaporation. This indicates the need for a distillation column for ethanol recovery before the remaining sugar solution can be used for fermentation purposes.

  • 266.
    Spencer, Maximilian
    KTH, Skolan för kemivetenskap (CHE).
    Fuel Cell for Food Preservation2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    As foodstuffs are being produced, transported and stored in greater quantities than ever before in human history and with an alarming amount of food products being lost to spoilage every year, new, environmentally friendly ways of preserving food products are being actively researched and developed in today’s world.

    Oxygen is a key pathway towards food decay and destruction, due to its dual roles as a source of respiration for the multitude of microorganisms that can cause food spoilage and through direct destruction through oxidation reactions within food products that cause oxidative deterioration.

    Fuel cells have the theoretical potential to be an energy efficient and environmentally friendly way of preserving food, such as fish, fruit and vegetables.  Because of their nature to consume oxygen through the electrochemical reactions that produces their electrical power, they have the potential to be used to reduce localised oxygen content for the storage and transportation of foods, minimising their spoilage, as well as potentially providing electrical energy for other components in potential control systems for the fuel cell.

    The purpose of this project is to design and build a PEM fuel cell and examine its potential for lowering of oxygen concentrations at the gas output at the cathode.  The outcome of these experiments are designed to validate the  theoretical capacity of fuel cells to reduce output oxygen concentrations to levels that are able to aid in the preservation of foodstuffs.  It is hoped that this study, in conjunction with the researched literature, can be used as a guide for future food shipping and storage methods.

    The experimental stage of this diploma work was unsatisfactory. The fuel cell was unable to produce a voltage and the reactant gases were unable to flow through the fuel cell due to a design flaw. Therefore the effectiveness of a fuel cell for depletion of oxygen to levels able to preserve food is based on the theoretical basis of the internal PEM fuel cell reactions, as well as studying past literature and patents.

    If the theoretical ability of the fuel cell is proven, it can be asserted that PEM fuel cells have the potential to be a real contender in the field of food preservation in shipping and storage, as well as offering greater levels of control for supplies for how and when they can ship their product. However this will require more independent research development work on the effects of low oxygen concentrations on a fuel cell operation as well as the preservation effects on a greater variety of foodstuffs. Furthermore, more research is required for more efficient and cheaper fuel cell catalysts or innovative designs are required to avoid concentration losses that arise from oxygen reduction at low oxygen levels.

  • 267.
    Staffas, Louise
    et al.
    IVL, Sweden.
    Karlfeldt Fedje, Karin
    Chalmers, Gothenburg, Sweden.
    Pettersson, Anita
    Högskolan i Borås, Borås, Sweden.
    Johansson, Inge
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Energi och cirkulär ekonomi.
    Behandling och återvinning av outnyttjade resurser i flygaska2016Rapport (Annet vitenskapelig)
    Abstract [sv]

    Föreliggande projekt har utgått från frågan "Hur kan användbara ämnen i flygaska från avfallsförbränning återföras till det industriella kretsloppet och restprodukten klassas som icke farligt avfall?"

    Sju askor har ingått i studien: en returträaska från fluidbäddpanna, en avfallsflygaska från fluidbäddpanna och fem avfallsflygaskor från rosterpannor.

    Askornas totalhalter av olika ämnen har mätts i syfte att undersöka vilka möjligt värdefulla substanser som finns. Cu, Ag, Al, Zn och Sb bedömdes som mest intressanta att återvinna. Metallhalterna i askorna är ofta låga utifrån återvinningsprocessaspekt, vilket gör att askorna ger mycket ballast i återvinningsaktörernas processer. Det finns andra sekundära råvaror, som t.ex. elektronik-skrot och slaggrus, som är mer intressanta för metall-återvinningsaktörer. För att kunna konkurrera med dessa strömmar måste askan upparbetas och/eller anrikas för att kunna passa i metallåtervinnings-processerna, vilket kan vara en framkomlig väg för några askor.

    Askorna lakades enligt SS-EN-127457-3 för att, tillsammans med totalhalterna, ge klarhet i vilka ämnen som förhindrar askorna att utgöra icke farliga avfall. Det är halterna av Cr och Pb, samt utlakningen av Cl-, Pb och SO42- som i de flesta fall utgör hinder för IFA-deponi av originalaskor.

    I syfte att undersöka möjligheten att laka ut metaller för återvinning lakades askorna med syra; dels olika koncentrationer av syra och dels med olika pH. Ingen av dessa metoder visade sig ge utlakning i sådan omfattning att det skulle vara en generellt framkomlig väg att utnyttja resurserna i flygaskorna från avfallsförbränning. I enskilda fall kan lakning för utvinning vara framgångsrikt.

    Som prioritet två låg att behandla askorna så att de uppfyller mottagningskriterierna för deponi för icke farligt avfall. Som ett första behandlingssteg tvättades askorna med vatten. Två tvätt-omgångar med vatten visade sig i vissa fall ge askor som uppfyller kriterierna. I andra fall skulle dispens för lakning av ett eller två ämnen per aska (Cl-, Cr, Pb, Sb och SO42-) behövas för att få tillstånd för deponering på IFA-deponi.

    Ett antal användningsområden för det salt som tvättas ut i vattentvättstegen har identifierats; bl.a. vägsalt, aluminiumåtervinning, PVC-tillverkning. Kravspecifikationer för dessa har jämförts med saltsammansättningen för saltet från askorna. PVC-tillverkning och aluminiumåtervinning är de två applikationer som bedöms vara mest intressanta att undersöka vidare.

    Flygaskor från avfallsförbränning måste undergå omfattande upparbetning för att utgöra attraktiva substrat för återvinning eller andra användningar.

  • 268.
    Strand, Michael
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    Gustafsson, Eva
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    Lin, Leteng
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    Yang, Jingjing
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    High-Temperature extraction of aerosol particles from biomass combustion and gasification2011Inngår i: European Aerosol Conference 2011, 2011Konferansepaper (Fagfellevurdert)
  • 269.
    Strandberg, Anna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Holmgren, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wagner, David R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Molinder, Roger
    Wiinikka, Henrik
    Umeki, Kentaro
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Effects of pyrolysis conditions and ash formation on gasification rates of biomass char2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 6, s. 6507-6514Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pyrolysis conditions and the presence of ash-forming elements significantly influence char properties and its oxidation or gasification reactivity. In this study, intrinsic gasification rates of char from high heating rate pyrolysis were analyzed with isothermal thermogravimetry. The char particles were prepared from two biomasses at three size ranges and at two temperatures. Reactivity dependence on original particle size was found only for small wood particles that had higher intrinsic char gasification rates. Pyrolysis temperature had no significant effect on char reactivity within the range tested. Observations of ash formation highlighted that reactivity was influenced by the presence of ash-forming elements, not only at the active char sites but also through prohibition of contact between char and gasification agent by ash layer formation with properties highly depending on ash composition.

  • 270.
    Suarez, J. A.
    et al.
    Universidad de Oriente, Santiago de Cuba, Cuba.
    Beaton, P. A.
    Universidad de Oriente, Santiago de Cuba, Cuba.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    A phenomenological energy model of biomass pyrolysis under autothermal fluidized bed conditions2006Inngår i: Energy Sources Part a-Recovery Utilization and Environmental Effects, ISSN 1556-7036, Vol. 28, nr 8, s. 705-714Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Cuba a variety of types of biomass is being investigated for energy conversion through thermochemical processes into solid, liquid, and gas products. A continuous bench fluidized bed pyrolysis has been designed and is currently under testing. In this article, a transport model has been developed to simulate the axial temperature fields in a bench. The model and experimental results indicated that (1) two zones exist inside of the fluidization column, the dense bed where the exothermic and endothermic reactions are active, and the freeboard zone where the temperature of the pyrolysis product decreases continuously; (2) the bed temperature increases with an increase in the air factor. The predicted temperature is in quantitative agreement with experimental measurements.

  • 271.
    Suarez, J. A.
    et al.
    Universidad de Oriente, Santiago de Cuba, Cuba.
    Beaton, P. A.
    Universidad de Oriente, Santiago de Cuba, Cuba.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Grimm, A.
    Autothermal fluidized bed pyrolysis of Cuban pine sawdust2006Inngår i: Energy Sources Part a-Recovery Utilization and Environmental Effects, ISSN 1556-7036, Vol. 28, nr 8, s. 695-704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxidative pyrolysis of Cuban pine sawdust was investigated using an autothermal fluidized bed reactor. Biomass particles were fed continuously (8.13 Kg/h) in a bed, fluidized by air gas. Experiments were conduced at three different dimensionless air factors 1, 1.5, and 2 (defined as ratio of actual air flow rate to stoichiometric air flow rate). The various physical and chemical characteristics of the pyrolysis products acquired in these conditions were identified. The results indicated that (1) the operating temperature can be correlated with the air factor; (2) the higher air factor promotes high temperature and contributes to the secondary reactions, which lead to less liquid; (3) the physicochemical characterization of the pyrolysis products indicated that the air factor, in the range studied, does not have a notable influence in their properties; (4) the liquid and char products obtained may be a potentially valuable source of chemical feedstocks.

  • 272.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Methods for Testing and Analyzing Lithium-Ion Battery Cells intended for Heavy-Duty Hybrid Electric Vehicles2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Lithium-ion batteries designed for use in heavy-duty hybrid vehicles are continuously improved in terms of performance and longevity, but they still have limitations that need to be considered when developing new hybrid vehicles.               

    The aim of this thesis has been to study and evaluate potential test and analysis methods suitable for being used in the design process when maximizing lifetime and utilization of batteries in heavy-duty hybrid vehicles.

    A concept for battery cell cycling on vehicles has been evaluated. The work included development of test equipment, verification of hardware and software as well as an extended period of validation on heavy-duty trucks. The work showed that the concept has great potential for evaluating strategies for battery usage in hybrid vehicles, but is less useful for accelerated aging of battery cells.                            

    Battery cells encapsulated in flexible packaging material have been investigated with respect to the durability of the encapsulation in a demanding heavy-duty hybrid truck environment. No effect on water intrusion was detected after vibration and temperature cycling of the battery cells.                   

    Aging of commercial battery cells of the type lithium manganese oxide - lithium cobalt oxide / lithium titanium oxide (LMO-LCO/LTO) was investigated with different electrochemical methods to gain a deeper understanding of the origin of performance deterioration, and to understand the consequences of aging from a vehicle manufacturer's perspective. The investigation revealed that both capacity loss and impedance rise were largely linked to the positive electrode for this type of battery chemistry.                          

    Postmortem analysis of material from cycle-aged and calendar-aged battery cells of the type LMO-LCO/LTO and LiFePO4/graphite was performed to reveal details about aging mechanisms for those cell chemistries. Analysis of cycle-aged LMO-LCO/LTO cells revealed traces of manganese in the negative electrode and that the positive electrode exhibited the most severe aging. Analysis of cycle-aged LFP/graphite cells revealed traces of iron in the negative electrode and that the negative electrode exhibited the most severe aging.

  • 273. Syed, Hanif Uddin
    et al.
    Nebamoh, Ikechukwu Patrick
    BillerudKorsnäs AB.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    A comparison of cold and hot caustic extraction of a spruce dissolving sulfite pulp prior to final bleaching2013Inngår i: Appita journal, ISSN 1038-6807, Vol. 66, nr 3, s. 229-234Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A magnesium sulfite pulp producer modified its pulping process to dissolving pulping in 2011 and needed a purification stage after the digester to obtain a sufficiently low hemicellulose content. The dissolving pulp was intended for viscose production and an R-18 value of at least 95% and an intrinsic viscosity below 550 dm(3)/kg was requested. The results showed, as could be expected, a correlation between lower dissolving pulp yield and a higher degree Of purification with respect to cellulose. The R-18 values and the intrinsic viscosities of the dissolving pulps were found to increase with increasing sodium hydroxide concentration and/or higher temperature in the extraction Stage. The pulp yield was found to be higher with higher temperature for the cold caustic extraction stage (CCE); for hot caustic extraction (HQ E) the pulp yield became lower with higher temperature. The specified R-18 value was easiest to reach using hot caustic extraction.

  • 274.
    Tammela, Petter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Preparation and characterization of a metal hydride electrode2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Metal hydrides are used as anode material in nickel metal hydride batteries and are of particular interest because of the potential to be a part of energy systems completely involving renewable sources (e.g. solar power, wind power etc.). Preparation and electrochemical characterization of metal hydride electrodes have not previously been performed at the Department of Chemistry – Ångström Laboratory. Two basic techniques that are desired to be used in the characterization are cyclic voltammetry and chronopotentiometry. This thesis work is aimed at preparation and electrochemical characterization of a metal hydride electrode and, as a complement, study the electrode with X-ray diffraction.

    LaNi3.55Co0.75Mn0.4Al0.3, a standard material for metal hydride electrodes previously studied by Khaldi et al. was chosen, to ensure that electrochemical absorption of hydrogen was possible, and to be able to compare electrochemical results [1-3]. LaNi3.55Co0.75Mn0.4Al0.3 was synthesized with arc melting, with additional annealing at 900˚C for five days, ground in a cemented carbide ball mill and sieved to less than 56 µm.

    Electrodes were prepared containing 90 wt.-% of LaNi3.55Co0.75Mn0.4Al0.3 powder, 5 wt.-% of polytetrafluoroethylene and 5 wt.-% of carbon black. The hydrogen absorption and desorption capabilities of the electrode were studied electrochemically with cyclic voltammetry and chronopotentiometry, and the structural changes associated with absorption of hydrogen was studied with X-ray diffraction.

    The capacity increased, probably from activation of the material, during initial cycling up to the maximum capacity of 294 mAh/g, obtained after 9 cycles, followed by a small decrease, probably caused by corrosion and passivation of the material, in capacity of the remaining 11 cycles. Activation of the material causes the charge and the discharge potential to shift to a more positive and a more negative value, respectively. The final values for the charge potential and the discharge potential were -841mV and -945 mV vs. Hg/HgO, respectively, after 16 cycles. Khalid et al. [1-3]reported a maximum capacity of 300 mAh/g, a charge potential of about -960 mV and a discharge potential of about -840 mV after 16 cycles the results obtained in this study are considered to be in good agreement with those reported.

    X-ray diffraction of the electrodes revealed, as expected, a cell volume change of the charged electrode compared to the discharged electrode. The change in cell volume corresponds to an estimated capacity of 303 mAh/g, which is very close to the, above mentioned, electrochemically obtained maximum capacity of 294 mAh/g.

  • 275.
    Tavast, Daniel
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Improved Usage of Wood Raw Material through Modification of the Kraft Process2015Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

       The kraft process is a complex system with many variables, and though the process is fairly well understood, there is still much we do not know.

     

       This thesis examines some aspects of the kraft process that could prove to be of interest for the pulp and paper industry, specifically, the impact of wood chip impregnation and of the chemical structure of xylan on spruce kraft pulp. The intent is to suggest modifications to the kraft process as it is used today.

     

       The effect of wood chip impregnation varies with the prevalent conditions, and increases the effect of the subsequent kraft cook. Longer impregnation at a lower temperature was found to increase screened pulp yield, reduce shives content, make it possible to reach a certain kappa number at a lower H-factor, and make it possible to reach a certain kappa number at a lower total alkali consumption.

     

       Xylan has previously been found to have a strength-enhancing effect on pulp, and the chemical structure of the xylan in question was found to be the main strength-enhancing factor. For spruce xylan, the structure that provides the largest increase in strength is not the same as the structure that increases the yield the most. Removing xylan was determined to have a negative impact on pulp strength.

     

       Xylan extracted from agro waste can be used as an additive to increase pulp strength. This could be viable, especially when combined with the production of green plastics from hemicelluloses extracted from the agro waste.

     

       A suggested configuration of a future pulp mill is presented, incorporating the following modifications to the now standard kraft cooking system:

    • impregnation at a lower temperature for a longer time;
    • extracting xylan-enriched black liquor at an early stage of the impregnation or cook, and adding this liquor at a late stage of the cook;
    • terminating the cook at a higher kappa number;
    • increasing oxygen delignification to compensate for the increased kappa number at the end of the cook, keeping the kappa number constant going into the bleaching plant; and
    • adding agro-waste xylan during oxygen delignification.
  • 276.
    TENGQVIST, MARIA
    KTH, Skolan för kemivetenskap (CHE).
    Teknoekonomisk studie för fullskalig produktion av biomassa från mikroalger2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Microalgae have received a surge in attention in the past decade as a source for renewable

    energy. They are currently used to produce high-value products but have the

    potential to produce biofuels such as bioethanol, biodiesel and biohydrogen among

    others. The present work is an evaluation of the feasibility of a process producing

    microalgae as a wet biomass paste through modeling of a real process. The production

    process of microalgal-derived low-value products has yet to be realized due to

    the low productivity in current culture systems, the high cost of such systems and

    the high cost of harvesting the microalgal biomass. An accurate and efficient model

    of this process is key in allowing for scale up to where it can contribute sufficiently

    to a more sustainable society.

    The model constructed evaluates the best alternative out of twelve configurations

    using data supplied by the user. The model is flexible in that it allows for modeling

    of different microalgae and different scales of production. Genetic engineering of the

    microalgae is modeled as three different cases: a reduction in the light-harvesting

    antennae, the expression of a fluorescent protein that by absorbing UV light emits

    photosynthetically active radiation and a combination of the two. The model is then

    run for the case relevant to the user. To evaluate the performance of the model and

    the viability of the modeled process, it was ran for the microalgae P. tricornutum and

    an annual production demand of 1000 ton wet biomass paste. The break-even price

    of the biomass was 8.79 Ä for the base case and 5.68 Ä with both cases of genetic

    engineering of the microalgal cell. The best configuration was found to be a tubular

    photobioreactor in the cultivation stage with flocculation-sedimentation followed by

    filtration in the harvesting stage.

    The model is capable of producing results that are in line with the current research

    and are thus deemed reasonable. With the level of accuracy that the model presently

    contains, it is a good representation of the production of microalgal biomass as a

    whole. However, to be able to draw definitive conclusions, more time and research

    is required.

  • 277.
    Trubetskaya, Anna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Kling, J.
    Brown, A.
    Tompsett, G.
    Umeki, K.
    Effects of Lignocellulosic Compounds on the Yield, Nanostructure and Reactivity of Soot from Fast Pyrolysis at High Temperatures2017Inngår i: Nordic Flame Days, Stockholm, 10-11 October, 2017Konferansepaper (Annet vitenskapelig)
  • 278.
    Trubetskaya, Anna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Talbot Barsberg, S.
    Development of CO2 neutral reductants in metallurgical industry from thermochemically produced biochar using DFT calculations2017Inngår i: ECI Meeting, Alba, Italy, August 20-25, 2017, 2017Konferansepaper (Annet vitenskapelig)
  • 279.
    Uddin, Arth
    et al.
    KTH, Skolan för kemivetenskap (CHE).
    Hosseini, Ashkan
    KTH, Skolan för kemivetenskap (CHE).
    Modeling a computational program with mass and energy balances2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    After the extension of the boiler 6 at Högdalenverket during 2010, there has been some problems in the form of increased carbon monoxide levels. There may be several explanations for this problem, which means that complete combustion doesent take place. There have also been problems with the ash-handling system and the sand returning systemt, this results in higher operating costs because it requires a higher consumption of inert material.The project was first divided into two phases, the first phase was to develop material and energy balances for the boiler but also introduce the parameters that we wanted to investigate further in order to possibly identify the causes of the problems that the boiler had. In the second phase experiments were going to be designed in consultation with the contact staff at Fortum to explore these parameters.During the project changes have been made in the project description, as it will require more time and more accurate planning to perform  the desired tests on the boiler. Three proposals on parameters that could be the cause of carbon monoxide problem was presented at the end of phase one and it was found that two of the proposals was not possible to carry out during the project because it would have affected economically and the availibility of the boilier.The third parameter, the bed quality effect on combustion experiment was designed in consultation with those responsible at Fortum.This experiment could also not be performed as there was some operational difficulties with the boiler during the project time. Instead, a description of the design for the experiment has been added to this project, which may at a later stage be used to investigate the bed quality impact on the carbon monoxide issues.Recent changes to the project description meant that purpose instead was to further develop the computational program created during the project's first phase and at the end of the project shall be submitted to the operators at Fortum. This calculation program takes into account the significant parameters that the boiler regulator is governed by today. The simulation program is developed using Microsoft Excel and is based on material and energy balances. This program can be used internally by Fortum to get an idea of ​​how the different mass flow rates would vary at different operating conditions and how the energy balance for the boiler would look like during the changes.When compared with materials and energy made by the boiler supplier revealed that the deviations are very small compared to what the program come up with and is caused mainly due to the assumptions made. These assumptions can be eliminated by performing experiments and collecting more data.The results gained by the calculation program has been compared with the results that was presented by the supplier during their boiler mapping, comparisons have been made regarding flue gas flows, fuel flows, combustion air flow, ash production and energy balances. It has apperad that the deviations are relatively small and the presented scheme provides a theoretical overall perspective of the boiler in line with reality.Although discussions have taken into consideration for the problem of elevated levels of carbon monoxide, and whether the measurement program can be developed further in the future.

  • 280.
    Valavi, Masood
    et al.
    University of Limerick, Ireland.
    Svärd, Michael
    University of Limerick, Ireland.
    Rasmuson, Åke C.
    University of Limerick, Ireland.
    Improving Estimates of the Crystallization Driving Force: Investigation into the Dependence on Temperature and Composition of Activity Coefficients in Solution2016Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 16, nr 12, s. 6951-6960Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of temperature and composition on solution activity coefficients has been investigated. Under most conditions, the temperature dependence of the activity coefficient is much weaker than the composition dependence. A novel and more accurate approach to estimate crystallization driving forces is proposed, where, rather than neglecting the activity coefficient ratio, it can be estimated from solid−liquid equilibrium data.

  • 281.
    Vera, C. M.
    et al.
    Phenomenex Australia, Pty Ltd, Lane Cove, NSW 2067, Australia.
    Shock, D.
    Phenomenex Australia, Pty Ltd, Lane Cove, NSW 2067, Australia.
    Dennis, G. R.
    Australian Centre for Research on Separation Science, School of Science and Health, University of Western Sydney, Penrith, NSW 2751, Australia.
    Samuelsson, Jörgen
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Enmark, Martin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Shalliker, R. Andrew
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper. Australian Centre for Research on Separation Science, School of Science and Health, University of Western Sydney, Penrith, NSW 2751, Australia.
    A preliminary study on the selectivity of linear polynuclear aromatic hydrocarbons in SFC using phenyl-type stationary phases2015Inngår i: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 121, s. 136-140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The retention behaviour of a homologous series of polyaromatic hydrocarbons was evaluated on two phenyl-type stationary phases in reversed phase supercritical fluid chromatography (SFC). These phases were the Synergi polar-RP phase and the Cosmosil 5PBB phase, both of which are polar end-capped and incorporate an ether in a propyl chain that tethers the phenyl ring to the silica surface. The Cosmosil 5PBB phase also has five bromine atoms on the phenyl ring. The retention capacity of the Cosmosil column was substantially greater than the Synergi column. However, selectivity on the Cosmosil column was effectively independent of the acetonitrile modifier composition in the CO2 mobile phase, whereas, selectivity on the Synergi column was greatly affected by the acetonitrile modifier in the CO2 mobile phase. The results from this study showed that selectivity and retention studies in HPLC cannot be used to predict selectivity and retention behaviour in SFC. (C) 2015 Elsevier B.V. All rights reserved.

  • 282.
    Vilaplana, Francisco
    et al.
    Division of Glycoscience, School of Biotechnology, AlbaNova University Centre, KTH Royal Institute of Technology, Stockholm, Sweden / Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Nilsson, Johanna
    Department of CollectionsThe Royal Armoury, Skokloster Castle, Hallwyl Museum, Stockholm, Sweden.
    Sommer, Dorte V. P.
    School of Conservation, Royal Danish Academy of Fine Arts Schools of Architecture, Design and Conservation, Copenhagen, Denmark.
    Karlsson, Sigbritt
    Högskolan i Skövde. Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Analytical markers for silk degradation: comparing historic silk and silk artificially aged in different environments2015Inngår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, nr 5, s. 1433-1449Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Suitable analytical markers to assess the degree of degradation of historic silk textiles at molecular and macroscopic levels have been identified and compared with silk textiles aged artificially in different environments, namely (i) ultraviolet (UV) exposure, (ii) thermo-oxidation, (iii) controlled humidity and (iv) pH. The changes at the molecular level in the amino acid composition, the formation of oxidative moieties, crystallinity and molecular weight correlate well with the changes in the macroscopic properties such as brightness, pH and mechanical properties. These analytical markers are useful to understand the degradation mechanisms that silk textiles undergo under different degradation environments, involving oxidation processes, hydrolysis, chain scission and physical arrangements. Thermo-oxidation at high temperatures proves to be the accelerated ageing procedure producing silk samples that most resembled the degree of degradation of early seventeenth-century silk. These analytical markers will be valuable to support the textile conservation tasks currently being performed in museums to preserve our heritage.

  • 283. Wang, Baoyuan
    et al.
    Cai, Yixiao
    Xia, Chen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Kim, Jung-Sik
    Liu, Yanyan
    Dong, Wenjing
    Wang, Hao
    Afzal, Muhammad
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Li, Junjiao
    Raza, Rizwan
    Zhu, Bin
    KTH, Skolan för datavetenskap och kommunikation (CSC), Medieteknik och interaktionsdesign, MID.
    Semiconductor-ionic Membrane of LaSrCoFe-oxide-doped Ceria Solid Oxide Fuel Cells2017Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 248, s. 496-504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel semiconductor-ionic La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-Sm/Ca co-doped CeO2 (SCDC) nanocomposite has been developed as a membrane, which is sandwiched between two layers of Ni0.8Co0.15Al0.05Li-oxide (NCAL) to construct semiconductor-ion membrane fuel cell (SIMFC). Such a device presented an open circuit voltage (OCV) above 1.0 V and maximum power density of 814 mW cm(-2) at 550 degrees C, which is much higher than 0.84 V and 300 mW cm(-2) for the fuel cell using the SCDC membrane. Moreover, the SIMFC has a relatively promising long-term stability, the voltage can maintain at 0.966 V for 60 hours without degradation during the fuel cells operation and the open-circuit voltage (OCV) can return to 1.06 V after long-term fuel cell operation. The introduction of LSCF electronic conductor into the membrane did not cause any short circuit but brought significant enhancement of fuel cell performances. The Schottky junction is proposed to prevent the internal electrons passing thus avoiding the device short circuiting problem.

  • 284.
    Wang, Yuming
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Jafari, Mohammad Javad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Wang, Nana
    Nanjing Tech Univ, Peoples R China.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Moons, Ellen
    Karlstad Univ, Sweden.
    Wang, Jianpu
    Nanjing Tech Univ, Peoples R China.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Huang, Wei
    Nanjing Tech Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Light-induced degradation of fullerenes in organic solar cells: a case study on TQ1:PC71BM2018Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 25, s. 11884-11889Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stability of organic solar cells (OSCs) is critical for practical applications of this emerging technology. Unfortunately, in spite of intensive investigations, the degradation mechanisms in OSCs have not been clearly understood yet. In this report, we employ a range of spectroscopic and transport measurements, coupled with drift-diffusion modelling, to investigate the light-induced degradation mechanisms of fullerene-based OSCs. We find that trap states formed in the fullerene phase under illumination play a critical role in the degradation of the open-circuit voltage (V-OC) in OSCs. Our results indicate that the degradation is intrinsic to the fullerenes in OSCs and that alternative acceptor materials are desired for the development of stable OSCs.

  • 285. Watterson, Samuel
    et al.
    Hudson, Sarah
    Svärd, Michael
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära. SSPC, University of Limerick, Ireland.
    Rasmuson, Åke C.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära. University of Limerick, Ireland.
    Thermodynamics of fenofibrate and solubility in pure organic solvents2014Inngår i: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 367, s. 143-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Calorimetric data on the melting of 1-methylethyl 2-[4-(4-chlorobenzoyl)-phenoxyl-2-methylpropanoate (fenofibrate) and the heat capacity of the solid and the melt have been determined, from which the Gibbs energy, enthalpy and entropy of fusion are calculated. Solid-liquid solubility data have been collected by a gravimetric method in seven pure solvents (methanol, ethanol, 1-propanol, 2-propanol, ethyl acetate, acetonitrile, and acetone) across a range of temperatures. Fenofibrate is much more soluble in ethyl acetate, acetonitrile and acetone compared to alcohols. In the alcohols the solubility increases with aliphatic chain length. The Gibbs energy of fusion is used to estimate the activity of the solid within a Raoult's law framework. Except for ethyl acetate solutions which are almost ideal, solutions in all evaluated solvents exhibit positive deviation from Raoult's law, and in the alcohols the activity coefficient ranges up to 25. It is shown that the heat capacity component of the enthalpy of fusion is not negligible at room temperature, in spite of the proximity to the melting point, and furthermore that the temperature dependence of the activity coefficient in the saturated solution has a governing influence on the van't Hoff enthalpy of solution in acetonitrile and the alcohols. Crystals obtained by two different methods from a range of solvents have been analysed by PXRD, FTIR and NMR spectroscopy, TGA and DSC, and have in all cases been shown to consist of the stable polymorph (form l).

  • 286.
    Wiezell, Katarina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Holmström, Nicklas
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Studying Low-Humidity Effects in PEFCs Using EIS II: Modeling2012Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, nr 8, s. F379-F392Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical impedance spectroscopy (EIS) and steady-state models have been developed to investigate the influence of water transport on the membrane and electrode performance, with focus on the low-frequency impedance. Models for the membrane, hydrogen anode and oxygen cathode were connected in order to take the influence of water concentration on proton conductivity and hydrogen kinetics into account. At low frequencies, below 1 Hz, a pseudo-inductive loop was predicted, resulting from the overlap of the responses from anode and membrane. The anode response could be coupled to changes in the kinetics and polymer conductivity in the active layer, and the membrane response to changes in conductivity with changing water profile. The low frequency capacitive part was attributed to drying of the anode side of the membrane, while the inductive part was attributed to the rehydration of the membrane with water produced at the cathode. The loop appeared at a frequency proportional to 1/L-2, where L is the membrane thickness. The model was successfully fitted to experimental data at different membrane thicknesses, relative humidities and current densities. The modeled data follow the same trends as experimental data, giving an increase in impedance at dry conditions and with thicker membranes.

  • 287.
    Wikström, Martina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Hansson, Lisa
    Linköpings Universitet.
    Alvfors, Per
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Socio-technical experiences from electric vehicle utilisation in commercial fleets2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 123, s. 82-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Commercial vehicle fleets are in many ways an attractive entry for electric vehicles into the transport system. In total, 174 electric vehicles have operated in commercial vehicle fleets and gathered socio-technical data over a period of 18 months, resulting in 302,000 all electric kilometres. This paper presents two perspectives regarding electric vehicle operations in commercial vehicle fleets - the functionality perspective, illustrated by the vehicle actions, and the user perspective that addresses the implementation of the task. The socio-technical analysis has resulted in four major findings. With time, the overall usage and the driving distance between charging occasions increase. It is not the passage of time that has influenced this behaviour but it may be explained as the result of accumulated experience. Swedish winter conditions show regression in usage, foremost due to users not familiar with the range reduction caused by the heating system. The need for public charging has been shown to be modest, which in an introductory phase with limited development of charging infrastructure, makes commercial vehicle fleets favourable to electrify over private vehicle fleets. According to deployment strategy, the different user groups' ability to incorporate the electric vehicles in their daily activities has been explored and this paper shows large potential for substituting traditional internal combustion engine vehicles within commercial vehicle fleets. Electric vehicles have been made available through a technology procurement scheme and have generated both kilometres and experience, which has come to increase the understanding of the usage of electric vehicles in commercial vehicle fleets.

  • 288.
    Willgert, Markus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Leijonmarck, Simon
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi. Swerea SICOMP AB, Sweden.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Malmström Jonsson, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Johansson, Mats K. G.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Cellulose nanofibril reinforced composite electrolytes for lithium ion battery applications2014Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, nr 33, s. 13556-13564Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study describes the synthesis and characterization of a series of four composite electrolytes for lithium ion battery applications. The two-phase electrolytes are composed of a soft, ionic conductive poly(ethylene glycol) (PEG) matrix having stiff nanofibrillated cellulose (CNF) paper as reinforcement to provide mechanical integrity. The reinforcing CNF is modified in order to create covalent bonds between the phases which is particularly beneficial when swelling the composite with a liquid electrolyte to enhance the ionic conductivity. After swelling the composite polymer electrolyte, forming a gelled structure, values of ionic conductivity at 5 x 10(-5) S cm(-1) and an elastic modulus around 400 MPa at 25 degrees C are obtained.

  • 289.
    Wreland Lindström, Rakel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Bränsleceller och material: Rapport från arbetsseminarium 16 juni 20112011Rapport (Annet (populærvitenskap, debatt, mm))
  • 290.
    Wreland Lindström, Rakel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Aguinaga, Luis Guerrero
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Oyarce, Alejandro
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Ubeda, Diego
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Ingratta, Mark
    Jannasch, Patric
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Fuel cell performance using a phosphonated polysulphone ionomer (PSUgPVPA) in the PEM cathode electrode2013Inngår i: Fuel Cell Membranes, Electrode Binders, And Mea Performance, Electrochemical Society, 2013, nr 23, s. 33-45Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Inexpensive and environmentally friendly electrolyte polymers that can be operated at higher temperatures and drier conditions are highly interesting for PEM fuel cells for automotive, portable power and stationary electricity generation applications. In this study an ionomer based on polysulfone grafted with poly(vinylphosphonic acid) (PSUgPVPA) in the cathode Pt/C catalyst layer (CL) was electrochemically characterized and compared to Nafion (R). The performance at different levels of humidity at 80 degrees C was evaluated by polarization and cyclic voltammetry. The results show that the performance of the PSUgPVPA-based cathode CL is comparable to that of Nafion (R) at 100% relative humidity (RH) but with some instabilities. However, at drier conditions significant losses of performance for the PSUgPVPA-based cathode was observed, concomitant to a reduced electrochemical surface area. The lower performance at low humidity is concluded to be due to a combination of lower proton conductivity and wettability or interference with oxygen reduction reaction at lower RH.

  • 291.
    Wreland Lindström, Rakel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Hildebrandt, Lars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Polymera bränsleceller (PEMFC): Teknikbevakningsrapport 20092009Rapport (Annet (populærvitenskap, debatt, mm))
  • 292.
    Wreland Lindström, Rakel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Kortsdottir, Katrin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Pérez Ferriz, Francisco Javier
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Conde Lopez, Julio Jose
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    The Effect of Hydrocarbon Impurities in the Hydrogen Fuel on the Anode Activity in PEMFC2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The reformate fuel cell has recently gained increasing attention both for APUs in vehicles

    operating on diesel and in stationary applications such as micro-CHP operating on natural

    or biogas. In addition to hydrogen gas, reformate contain considerable amounts of CO2,

    nitrogen, water vapour and traces of CO, sulphur species and hydrocarbons. CO and H2S

    are well known poisons to the anode [1] but the influence of hydrocarbon species in the

    fuel cell has not been much investigated. We have previously investigated toluene [2] and

    ethene [3] on the anode Pt/C catalyst in the PEM fuel cell. In this paper we will discuss the

    influences of alkenes and alkanes in the light of some novel results on the effect of

    propene, propane and methane in the PEM fuel cell. We have especially focused on the

    adsorption and deactivation phenomena of low concentrations of contaminant on a Pt/C

    catalyst. In the experiments, in situ stripping voltammetry and on-line mass spectrometer

    were employed. The effects of adsorption potential and temperature are discussed. We

    show that propene is more poisonous to the Pt/C catalyst than ethene as it is adsorbed on

    the catalyst surface within the Hupd region and forms an adlayer that can be oxidized in two

    steps between 0.5-1 V (at 80°C, 90%RH) or be hydrogenated to propane in the Hupd region

    and in the presence of hydrogen.

  • 293.
    Wreland Lindström, Rakel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Teknikbevakning av polymera bränsleceller (PEFC)2011Rapport (Annet (populærvitenskap, debatt, mm))
  • 294.
    Xu, Johanna
    et al.
    Lulea Univ Technol, Dept Engn Sci & Math, S-97189 Lulea, Sweden..
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Varna, Janis
    Lulea Univ Technol, Dept Engn Sci & Math, S-97189 Lulea, Sweden..
    Multiphysics modeling of mechanical and electrochemical phenomena in structural composites for energy storage: Single carbon fiber micro-battery2018Inngår i: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 37, nr 10, s. 701-715Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a framework for multiphysics modeling of a novel type of multifunctional composite material, structured on microscale, with ability to function as battery cell in addition to carry mechanical load. The micro-battery consists of a single carbon fiber surrounded by very thin solid electrolyte coating and embedded in a matrix which is a porous material containing active particles able to intercalate lithium. During battery operation (discharging and charging) the structural battery constituents undergo volume changes, caused by lithium-ion movement. The presented mathematical model is solved numerically using COMSOL software and results are used to analyze the physical phenomena occurring in the structural battery material. Parametric analysis is performed to reveal the significance of geometrical parameters like fiber volume fraction in the battery and the porosity content in the matrix on the multifunctional performance of the composite unit including its swelling/shrinking during charging/discharging.

  • 295.
    Xu, Xingxing
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Uppsala University.
    Makaraviciute, Asta
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Pettersson, Jean
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Considerations for the Cyclic Voltammetry of Gold in Sulfuric Acid Solutions2018Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A comprehensive understanding of the cyclic voltammetry (CV) for gold surfaces is essential for advanced applications. In the present study, a series of experiments were designed to investigate CV for gold under different experimental conditions when using a conventional configuration of a Ag/AgCl/sat. KCl reference electrode and a platinum wire counter electrode. The interferences introduced by the configuration were reflected in the three fingerprint regions of the voltammograms. It was found that the shape of the voltammograms was less reproducible at a lower sample volume when the cycle number was increased. This observation could be explained by different concentrations of Cl- leaking from the reference electrode and platinum dissolved from the counter electrode. The reproducibility of the gold oxidation and reduction (Ox/Re) region in the voltammograms was improved when gold dissolution and re-deposition caused by Cl- leakage was eliminated by using a bridge. In the hydrogen evolution and oxidation reactions (HER/HOR) region the catalytic performance of the gold electrode could be minimized by replacing the platinum counter electrode with a graphite rod. Alternatively, it could be enhanced by increasing the surface ratio of the co-deposited platinum to gold. In the electric double layer (EDL) region, peaks dependent on the concentrations of Cl- and SO42- were observed. To account for the occurrence of these peaks, a new mechanism based on the formation of neutral gold (I) complexes at very low Au+ concentrations, was proposed. 

  • 296.
    Yakkala, Bhaskarrao
    et al.
    Saveetha Univ, Saveetha Sch Engn, Dept Elect & Commun Engn, Chennai, Tamil Nadu, India..
    Narayanan, R.
    Sch Mech & Business Sci, VIT Chennai Campus, Chennai, Tamil Nadu, India..
    Sreejith,
    KTH.
    COMPUTATIONAL DENSITY FUNCTIONAL THEORY (DFT) APPROACH ON SMART CATALYSTS UTILIZED IN FUEL CELL TECHNOLOGY2018Inngår i: The IIOAB Journal, ISSN 0976-3104, Vol. 9, s. 14-17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Concepts of nanotechnology are utilized in numerous fields. Sustainable or non-conventional source of power is one area in which this smart technology is widely applied. The catalytic property of nanomaterials in Fuel Cell Technology (FCT) is worth mentioning as it would increase efficiency to a great extent. In this work, Monte-Carlo calculations are carried out to check the adsorption of OH-molecule on various platinum catalysts doped with Ru, W, Co and Pd. The catalyst was then made to adsorb on two separate amorphous carbon blocks that acted as cathode and anode respectively. The Membrane Electrode Assembly (MEA) of the fuel cell was made with nafion membrane and Co-doped Pt electrodes. Adsorption of OH- molecule on the final restructured MEA of the fuel cell was studied.

  • 297. Yang, Lin
    et al.
    Li, Xin
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Qu, Yi
    Qu, Weisong
    Zhang, Xiao
    Hang, Yandi
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Hua, Jianli
    Red turn-on fluorescent phenazine-cyanine chemodosimeters for cyanide anion in aqueous solution and its application for cell imaging2014Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 203, s. 833-847Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two chemodosimeters PDMI and PMI for cyanide detection were designed and synthesized based onphenazinecyanine dyes with N-methyl indolium group as receptor unit. According to the specific reactivity of indolium C-N+ bond against cyanide anion, both of them featured high sensitivity with detectionlimit of 1.4 mu M and 200 nM, respectively, and high selectivity against other anions. The quenching effecton phenazine-cyanine fluorophore by strong intramolecular charge transfer (ICT) from phenazine donorto indolium receptor made both PDMI and PMI non-emissive at the original state. After addition ofcyanide, the ICT effect decreased and vanished leading to dramatic " off-on" fluorescence enhancement. PDMI which proceeded bilateral electrophilic reaction toward cyanide anion provided an emission signal at 580 nm in HEPES buffer with naked-eye detectable color change. Probe PMI utilized an unreactiveformyl group instead of one reactive N-methyl indolium group as the electron-withdrawing component. Due to the unilateral recognition process for cyanide the ICT orientation of PMI was redirectedthus exhibited fluorescence enhancement with maximum emission at 630 nm. Meanwhile, PMI wasapplied for monitoring intracellular cyanide in Hela cells and proved to achieve "off-on" fluorescentsignal confirmed by confocal laser scanning microscopic imaging.

  • 298.
    Yang, Weihong
    et al.
    KTH, Tidigare Institutioner, Materialvetenskap.
    Blasiak, Wlodzimierz
    KTH, Tidigare Institutioner, Materialvetenskap.
    Length and volume in LPG flame using high-temperature and low oxygen oxidizer2004Inngår i: International Symposium on Combustion, Abstracts of Works-in-Progress Posters, 2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of a high temperature combustion oxidizer at different oxygen concentration on flame length and volume was numerically studied. LPG was used as the fuel. Flame length increased with either the decrease of oxygen content, or increase of oxidizer temperature, or decrease of fuel temperature. The flame length was independent of the fuel flow rate and the diameter of the fuel nozzle for studies cases. Flame volume increased either with the decrease of oxygen content and increase of oxidizer temperature, or with the reduction of fuel temperature, or with the increasing in fuel firing rate. Flame volume depended very much on the oxygen concentration in the oxidizer. This is an abstract of a paper presented at the 30th International Symposium on combustion (Chicago, IL 7/25-30/2004).

  • 299.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Birbas, Daniella
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Márquez Montesino, Francisco
    niversidad de Pinar del Río, Departamento de Quimica, Pinarde de Río, Cuba,.
    Preparation of Activated Carbon: Forest residues activated with Phosphoric Acid and ZincSulfate2011Inngår i: VII EDICIÓN DE LA CONFERENCIA CIENTÍFICA INTERNACIONAL MEDIOAMBIENTE SIGLO XXI, MAS XXI 2011, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the preparation of activated carbon by chemical activation. The selected biomass used as precursor is sawdust from both Cuban and Swedish Pine tree. Phosphoric acid and Zinc Sulphate are the chemical reagents. The objective is to study the influence of acid concentration, impregnation ratio and activation temperature on adsorption performance of the obtained activated carbon.

    The experiments with phosphoric acid activation show that treatment with 40% acid concentration at 400 °C produce an activated carbon with good properties for ammonia adsorption and good iodine number. If a 30% phosphoric acid is used for activation, an activation temperature of 500 °C is recommended. With an impregnation ratio of 1, good adsorption was obtained in the activated carbon produced from Swedish pine while using Cuban pine a higher adsorption was obtained with an impregnation ratio of 2.

    The experiments with Zinc Sulphate activation show that activation conditions of 20% zinc sulphate concentration, 400 °C and impregnation ratio: 1 are enough to produce an activated carbon with good properties for ammonia adsorption. The adsorption of carbon tetrachloride was lower. Activated carbons produced with 10 % zinc sulphate concentration, 0.5 impregnation ratio and 400 °C activation temperature (the mildest studied conditions) show already good iodine number and BET surface area.    

  • 300.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Grimm, Alejandro
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Biosorbentes para la remoción de cobre (II) en soluciones acuosas2005Konferansepaper (Fagfellevurdert)
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