Change search
Refine search result
6789101112 401 - 450 of 2474
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 401.
    Chidambaram, R
    et al.
    Karobio.
    Garg, N
    Karobio.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Gracin, Sandra
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Improved crystalline material2006Patent (Other (popular science, discussion, etc.))
  • 402.
    Chinungi, Don
    KTH, School of Chemical Science and Engineering (CHE).
    Surface Treatment of Photocatalyst Metal Supports for VOCs Abatement Applications2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this work, the preparation of photocatalysts’ metal support for applications in purification

    of industrial gas emissions has been studied. The supports normally used in literature are

    ceramics, but they are not suitable for industrial applications. Stainless steel and aluminium

    are much more common in full-scale reactors and were therefore chosen in this investigation.

    Chemical etching, anodisation, electrochemical DC etching and AC etching treatment methods

    were used to modify the surface morphology of aluminium and stainless steel plates in

    order to improve the mechanical stability of photocatalyst (TiO2) coating. Two-part epoxysiloxane

    hybrid (ESH) and sodium silicate adhesives have been evaluated for use as TiO2

    binder. Dip and spray coating techniques were employed for preparing TiO2 coatings on

    blank plates, pretreated plates, ESH and sodium silicate coated plates. Stainless steel electrochemically

    etched in dilute aqua regia gave the most mechanically stable coating. It was

    demonstrated that a high microscale surface roughness of the support improves the mechanical

    stability of TiO2. Additionally, photocatalytic performance of the coating was higher

    than that coated on ceramic support. The mechanical stability of TiO2 coated on ESH and

    sodium silicate using dip and spray coating techniques was exceedingly improved. However,

    Energy Dispersive Spectroscopy (EDS) analysis showed that TiO2 was embedded in the adhesives.

    Nevertheless, sprinkling of TiO2 powder on sodium silicate presented a very stable

    coating regardless of high TiO2 loading. It was also shown that coating of sodium silicate on

    pretreated plates did not a↵ect the mechanical stability of TiO2 coating. A well coated and

    uniform surface of TiO2 was achieved by spray coating technique.

  • 403. Chisti, Yusuf
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy from algae: Current status and future trends: Algal biofuels - A status report2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 10, p. 3277-3279Article in journal (Other academic)
  • 404.
    Cho, Sung-Woo
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Protein-based Packaging Films, Sheets and Composites: Process Development and Functional Properties2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The depletion of the petroleum resources and a number of environmental concerns led to considerable research efforts in the field of biodegradable materials over the last few decades. Of the diverse range of biopolymers, wheat gluten (WG) stands out as an alternative to synthetic plastics in packaging applications due to its attractive combination of flexibility and strength, high gas barrier properties under low humidity conditions and renewability. The availability of raw materials has also been largely increased with an increase in the production of WG as a low-cost surplus material due to increasing demand for ethanol as fuel. In this study, WG was processed into films, sheets and composites using some of the most widely used techniques including solution casting, compression molding, extrusion and injection molding, accompanying process optimizations and characterization of their functional properties. This thesis consists mainly of six parts based on the purpose of the study. The first part addresses the aging and optical properties of the cast film in order to understand the mechanisms and reasons for the time-dependant physical and chemical changes. The films plasticized with glycerol were cast from acidic (pH 4) and basic (pH11) solutions. The film prepared from the pH 11 solution was mechanically more stable upon aging than the pH 4 film, which was initially very ductile but became brittle with time. It was revealed that the protein structure of the pH 4 film was initially less polymerized/aggregated and the polymerization increased during storage but it did not reach the degree of aggregation of the pH 11 film. During aging, the pH 4 film lost more mass than the pH 11 film mainly due to migration of glycerol but also due to some loss of volatile mass. In addition the greater plasticizer loss of the pH 4 film was presumably due to its initial lower degree of protein aggregation/polymerization. Glycerol content did not significantly change the opacity and pH 4 films showed good contact clarity because of less Maillard reaction. In the second part, the heat-sealability of WG films was investigated, using an impulse-heat sealer, as the sealability is one of the most important properties in the use of flexible packaging materials. It was observed that the WG films were readily sealable while preserving their mechanical integrity. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed. The third part describes the possibility of using industrial hemp fibers to reinforce wheat gluten sheets based on evaluation of the fiber contents, fiber distribution and bonding between the fibers and matrix. It was found that the hemp fibers enhanced the mechanical properties, in which the fiber contents played a significant role in the strength. The fiber bonding was improved by addition of diamine as a cross-linker, while the fiber distribution needed to be improved. The fourth part presents a novel approach to improve the barrier and mechanical properties of extruded WG sheets with a single screw extruder at alkaline conditions using 3-5wt.% NaOH with or without 1 wt.% salicylic acid. The oxygen barrier, at dry conditions, was improved significantly with the addition of NaOH, while the addition of salicylic acid yielded poorer barrier properties. It was also observed that the WG sheets with 3 wt.% NaOH had the most suitable combination of low oxygen permeability and relatively small time-dependant changes in mechanical properties, probably due to low plasticizer migration and an optimal protein aggregation/polymerization. In the fifth part WG/PLA laminates were characterized for the purpose of improving the water barrier properties. The lamination was performed at 110°C and scanning electron microscopy showed that the laminated films were uniform in thickness. The laminates significantly suppressed the mass loss and showed promising water vapor barrier properties in humid conditions indicating possible applications in packaging. The final part addresses the development of injection molding processes for WG. Injection-molded nanocomposites of WG/MMT were also characterized. WG sheets were successively processed using injection molding and the process temperatures were found to preferably be in a range of 170-200°C, which was varied depending on the sample compositions. The clay was found to enhance the processability, being well dispersed in the matrix. The natural clay increased the tensile stiffness, whereas the modified clay increased the surface hydrophobicity. Both clays decreased the Tg and increased the thermal stability of the nanocomposites. The overall conclusion was that injection molding is a promising method for producing WG items of simple shapes. Further studies will reveal if gluten can also be used for making more complex shapes.

  • 405.
    Cho, Sung-Woo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Blomfeldt, Thomas O. J.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Halonen, Helena
    Gällstedt, Mikael
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wheat Gluten-Laminated Paperboard with Improved Moisture Barrier Properties: A New Concept Using a Plasticizer (Glycerol) Containing a Hydrophobic Component (Oleic Acid)2012In: International Journal of Polymer Science, ISSN 1687-9422, p. 454359-Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel approach to reduce the water vapor transmission rate (WVTR) and water absorbance of wheat gluten/paperboard laminates by introducing a hydrophobic component (oleic acid (OA)) into the hydrophilic plasticizer (glycerol). Whereas the paperboard showed immeasurably high WVTR, the laminate with gluten/glycerol yielded finite values. More importantly, by incorporating 75wt.% OA into the plasticizer, the WVTR and water absorbance were reduced by, respectively, a factor of three and 1.5-2. Of particular interest was that the mechanical properties were not changing dramatically between 0 and 50 wt.% OA. The results showed clear benefits of combining a gluten film with paperboard. Whereas the paperboard provided toughness, the WG layer contributed with improved moisture barrier properties. In addition, WVTR indicated that the paperboard reduced the swelling of the outer gluten/glycerol layer in moist conditions; a free standing gluten/glycerol film would yield infinite, rather than finite, WVTR values.

  • 406.
    Cho, Sung-Woo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gällstedt, Mikael
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Effects of glycerol content and film thickness on the properties of vital wheat gluten films cast at pH 4 and 12010In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 117, no 6, p. 3506-3514Article in journal (Refereed)
    Abstract [en]

    This study deals with the optical properties and plasticizer migration properties of vital wheat gluten (WG) films cast at pH 4 and 11. The films contained initially 8, 16, and 25 wt % glycerol and were aged at 23 degrees C and 50% relative humidity for at least 17 weeks on a paper support to simulate a situation where a paper packaging is laminated with an oxygen barrier film of WG. The films, having target thicknesses of 50 and 250 mu m, were characterized visually and with ultraviolet/visible and infrared spectroscopy; the mass loss was measured by gravimetry or by a glycerol-specific gas chromatography method. The thin films produced at pH 4 were, in general, more heterogeneous than those produced at pH 11. The thin pH 4 films consisted of transparent regions surrounding beige glycerol-rich regions, the former probably rich in gliadin and the latter rich in glutenin. This, together with less Maillard browning, meant that the thin pH 4 films, in contrast to the more homogeneous (beige) thin pH 11 films, showed good contact clarity. The variations in glycerol content did not significantly change the optical properties of the films. All the films showed a significant loss of glycerol to the paper support but, after almost 9 months, the thick pH 11 film containing initially 25 wt % glycerol was still very flexible and, despite a better contact to the paper, had a higher residual glycerol content than the pH 4 film, which was also more brittle.

  • 407.
    Cho, Sung-Woo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gällstedt, Mikael
    KTH.
    Hedenqvist, Mikael S
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Properties of Wheat Gluten/Poly(lactic acid) Laminates2010In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 58, no 12, p. 7344-7350Article in journal (Refereed)
    Abstract [en]

    Laminates of compression-molded glycerol-plasticized wheat gluten (WG) films surrounded and supported by poly(lactic acid) (PLA) films have been produced and characterized. The objective was to obtain a fully renewable high gas barrier film with sufficient mechanical integrity to function in, for example, extrusion-coating paper/board applications. It was shown that the lamination made it possible to make films with a broad range of glycerol contents (0-30 wt %) with greater strength than single unsupported WG films. The low plasticizer contents yielded laminates with very good oxygen barrier properties. In addition, whereas the unsupported WO films had an immeasurably high water vapor transmission rate (WVTR), the laminate showed values that were finite and surprisingly, in several cases, also lower than that of PLA. Besides being a mechanical support (as evidenced by bending and tensile data) and a shield between the WG and surrounding moisture, the PLA layer also prevented the loss of the glycerol plasticizer from the WG layer. This was observed after the laminate had been aged on an "absorbing" blotting paper for up to 17 weeks. The interlayer adhesion (peel strength) decreased with decreasing glycerol content and increasing WG film molding temperature (130 degrees C instead of 110 degrees C). The latter effect was probably due to a higher protein aggregation, as revealed by infrared spectroscopy. The lamination temperature (110-140 degrees C) did not, however, have a major effect on the final peel strength.

  • 408.
    Cho, Sung-Woo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Ullsten, Henrik
    STFI Packforsk AB.
    Gällstedt, Mikael
    STFI Packforsk AB.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Heat-sealing properties of compression-molded wheat gluten films2007In: Journal of Biobased Materials and Bioenergy, ISSN 1556-6560, Vol. 1, no 1, p. 56-63Article in journal (Refereed)
    Abstract [en]

    The impulse heat-sealing properties of wheat gluten films were investigated. Films containing 30 wt% glycerol were compression molded at 100-130 degrees C and then sealed in a lap-shear or peel-test geometry at 120-175 degrees C. The tensile properties of the pristine films and the lap-shear and peel strength of the sealed films were evaluated and the seals were examined by scanning electron microscopy. Glycerol was added to the film surfaces prior to sealing in an attempt to enhance the seal strength. It was observed that the wheat gluten films were readily sealable. At a 120 degrees C sealing temperature and without glycerol as adhesive, the lap-shear strength was greater than or similar to that of polyethylene film, although the peel strength was poorer. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed, especially in the absence of glycerol adhesive, from a cohesive (material failure) to an adhesive type. From previous results, it is known that the high-temperature (130 degrees C) compression-molded film was highly cross-linked and aggregated, and this prevents molecular interdiffusion and entanglement and thus leads to incomplete seal fusion and, in general, adhesive failure. The presence of glycerol adhesive had a beneficial affect on the peel strength but no, or only a minor, effect on the lap-shear strength.

  • 409.
    Chondrogiannis, Georgios
    KTH, School of Chemical Science and Engineering (CHE).
    Pretreatmenteffect on induction time and polymorphic outcome of tolbutamide crystallizationin 1-propanol2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this project, the effect of solution thermal and structural history on nucleation was investigated. Many researchers have shown that temperature and duration of pretreatment has an influence on induction time, polymorphic outcome and metastable zone width. Here, solution of tolbutamide in 1-propanol was first prepared with same conditions, to “standardize” and control the initial solution history. Next, pretreatment of varied duration and temperature was applied to introduce different solution history. Then, nucleation began in 9℃, and induction time and polymorphic outcome were measured. Two batches of 30 isolated nucleation experiments each, were done per set of conditions. The results showed an impact on induction time and polymorphic outcome. However, this change cannot be clearly correlated with the conditions of pretreatment. Furthermore, the deviation between series of experiments that were performed under the same set of conditions, showed that the parameters affecting induction time and polymorphism were not controlled sufficiently to reach a safe conclusion.

    Moreover, the effect of solution filtration right before nucleation was investigated. This filtration step decreased experimental induction time from 160 minutes to less than 5. It is possible that this filtration step removed the solution’s structural memory, which accelerated nucleation. However, the effect of evaporation on concentration for example, or other parameters was not investigated.

    Furthermore, the effect of using filtration with 0.1 and 0.2 μm filters was examined. It was found that using 0.1 filter results in decreased median induction time by a factor of 4. Finally, filtration before standardization resulted in a 1.5% increase in concentration compared to solution that was not filtered. Filtration with 0.1 μm filter before standardization decreased median induction time by a factor of 4, as compared to using a 0.2 μm filter.

  • 410. Christou, Stavroula Y.
    et al.
    Birgersson, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Efstathiou, Angelos M.
    Reactivation of severely aged commercial three-way catalysts by washing with weak EDTA and oxalic acid solutions2007In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 71, no 3-4, p. 185-198Article in journal (Refereed)
    Abstract [en]

    Ethylene diamine tetraacetic acid (EDTA) which is a well-known reagent for its metal extraction efficiency was studied for the first time towards the improvement of the catalytic activity and oxygen storage and release properties (OSC) of severely aged commercial three-way catalysts (TWC) on a laboratory scale. Optimization of the experimental parameters of EDTA-washing procedure of TWC was carried out by varying the washing time, volumetric flow rate, and temperature of EDTA solution. The EDTA-washing procedure of TWC was compared with that of oxalic acid-washing regarding their efficiency in removing P, Pb, S, Ca, Zn, Fe, Cu, Cr, Ni, and Mn, all known TWC contaminants that many of them cause severe deterioration of TWC's activity and oxygen storage and release properties. EDTA appears to be significantly efficient in removing Pb, Zn, Ca, Mn, Fe, Cu and Ni metal contaminants and sulfur but not of phosphorus (P). Phosphorus-containing species were found to be efficiently removed from the aged TWCs after oxalic acid washing. All regeneration procedures applied led to a significant partial recovery of catalytic activity of TWC (CO, CxHy and NOx conversions) under real exhaust gas conditions (dynamometer tests) due to the removal of large amounts of contaminants accumulated on the aged TWC. The washing procedures using oxalic acid alone or in combination with EDTA led to more significant improvements of both catalytic and OSC performance compared with those of EDTA washing alone. This was due to the ability of oxalic acid to remove P-containing compounds which appear to be one of the main causes of commercial three-way catalyst deactivation. (C) 2006 Elsevier B.V. All rights reserved.

  • 411.
    Chroona, Gustaf
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Duman, Isa
    KTH, School of Chemical Science and Engineering (CHE).
    Luftrening för industriella processer - Dimensionering av ett luftreningssystem i pilotskala2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Industrial processes in the food industry very often produce airstreams of contaminated air. The impurities can be both particulates and gaseous compounds. Controlling these emissions is of a great concern both regarding governmental and social requirements.

    The overall aim with the thesis was to construct an easily portable, pilot scale air purification system. The main purpose with the pilot scale system was to enable testing of contaminated air generated from industries. The results from the industry tests with the pilot scale system would reveal valuable information that could be used later for the design of a large scale cleaning system.

    The work was assigned by Ozone Tech Systems. The company is specialized in ozone treat-ments intended for industrial and domestic uses. The work done within the thesis project was performed in close relations with equipment suppliers and Ozone Tech System personnel.

    The design of the pilot scale air purification system was based on contaminated air, generated from fish smokehouses. The smoke that is involved in the hot smoking process is derived in conjunction with alder chips smoldering. Although the pilot scale system was designed for purifying air generated from fish smokehouses, it should also suit other processes that gener-ate similar air emissions. Emission factors, literature data and measured values played an im-portant role for estimating the air composition in the air generated from the specific process. The treatment objective was determined by European regulations as well as a desired reduc-tion of unwanted odors. The odor was found to mainly be caused by volatile organic com-pounds (VOC).

    The pilot system was predefined to consist of a primary step of particle separation, oxidation with ozone, particle separation consisting of a HEPA 13 filtration stage and at last adsorption with activated carbon. During the design process it was decided to use a venturi scrubber as the primary particle separator and to add a pre-filter stage before the HEPA 13 filter.

    The work has resulted in a theoretical design of the air purification system. The units are de-tachable which provides a simple transportation as well as the possibility to use an adaptable combination of the units.

    The purchase of equipment was not a part of the thesis, but the coordination of the purchase has been completed ensuring that the purchase could be done after the end of the project. In order for the system to work, a fan needs to be installed and pipe connections between the units have to be designed and purchased, but this was not a part in the project.

  • 412.
    Chung, Kevin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Effekten av gammastrålning på svällningskapaciteten för bentonitlera2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SKB (Swedish Nuclear Fuel and Waste Management Company) is planning to store used nuclear fuel deep down in the bedrock, KBS-3 method. The repository will consist of 3 protective barriers, the copper canister, the bentonite clay and the bedrock. Bentonite clay has excellent barrier properties and is used to enclose the canister. The clay expands when it’s adsorbing water and has as function to act as a sealing material to prevent leakage of radionuclides. This work is focused on the gamma-ray effects on bentonite clays swelling capacity. The work is done in the department of Applied Physical Chemistry at the Royal Institute of Technology.

    Bentonite clay of the type Wyoming MX-80 and a total gamma-dose of 34,56 kGy with a Caesium-137 source where used in this work. To study the swelling capacity of bentonite clay, it was pressed to pellets with a dry density of 2260 kg/m3 and were put in into measuring tubes filled with deionized water. The swelling was documented with a camera.

    The results from the swelling capacity experiment showed no noticeable difference in swelling capacity between irradiated and nonirradiated clay.

  • 413. Cieślik, M.
    et al.
    Zimowski, Sławomir
    Golda, M.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Rakowski, W.
    Kotarba, A.
    Engineering of bone fixation metal implants biointerface - Application of parylene C as versatile protective coating2012In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 32, no 8, p. 2431-2435Article in journal (Refereed)
    Abstract [en]

    The tribological and protective properties of parylene C coatings (2-20 ÎŒm) on stainless steel 316L implant materials were investigated by means of electrochemical measurements and wear tests. The thickness and morphology of the CVD prepared coatings were characterized by scanning electron and laser confocal microscopy. The stability of the coatings was examined in contact with Hanks' solution and H 2O 2 (simulating the inflammatory response). It was concluded that silane-parylene C coating with the optimum thickness of 8 ÎŒm exhibits excellent wear resistance properties and limits the wear formation. The engineered versatile coating demonstrates sufficient elastomer properties, essential to sustain the implantation surgery strains and micromotions during long-term usage in the body.

  • 414. Ciosek Högström, Katarzyna
    et al.
    Lundgren, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Wilken, Susanne
    Zavalis, Tommy G.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Edström, Kristina
    Jacobsson, Per
    Johansson, Patrik
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Impact of the flame retardant additive triphenyl phosphate (TPP) on the performance of graphite/LiFePO4 cells in high power applications2014In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 256, p. 430-439Article in journal (Refereed)
    Abstract [en]

    This study presents an extensive characterization of a standard Li-ion battery (LiB) electrolyte containing different concentrations of the flame retardant triphenyl phosphate (TPP) in the context of high power applications. Electrolyte characterization shows only a minor decrease in the electrolyte flammability for low TPP concentrations. The addition of TPP to the electrolyte leads to increased viscosity and decreased conductivity. The solvation of the lithium ion charge carriers seem to be directly affected by the TPP addition as evidenced by Raman spectroscopy and increased mass-transport resistivity. Graphite/LiFePO4 full cell tests show the energy efficiency to decrease with the addition of TPP. Specifically, diffusion resistivity is observed to be the main source of increased losses. Furthermore, TPP influences the interface chemistry on both the positive and the negative electrode. Higher concentrations of TPP lead to thicker interface layers on LiFePO4. Even though TPP is not electrochemically reduced on graphite, it does participate in SEI formation. TPP cannot be considered a suitable flame retardant for high power applications as there is only a minor impact of TPP on the flammability of the electrolyte for low concentrations of TPP, and a significant increase in polarization is observed for higher concentrations of TPP.

  • 415.
    Claesson, Hans
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Doyle, M.
    Manson, J. A. E.
    Rheological behaviour during UV-curing of a star-branched polyester2002In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 44, no 1, p. 63-67Article in journal (Refereed)
    Abstract [en]

    Using a rheometer coupled with an UV-light generator, the viscoelastic behaviour during the fast cure of star-branched polyester is investigated. The 32 arm star polymers consist of a hyperbranched polyester core, Boltorn(TM) and linear grafts of poly(E-caprolactone) (degree of polymerisation: 20-52) with methacrylate end groups. The resins are crystalline and the melting points range from 34 to 50degreesC; films can be formed and cured below 80degreesC. The crossover of G' and G was used as the gel point. The time to reach the gel point, a few seconds, increases linearly with molecular weight.

  • 416.
    Claesson, Hans
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Scheurer, Curzio
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Paulus, W.
    Schwalm, R.
    Semi-crystalline thermoset resins: tailoring rheological properties in melt using comb structures with crystalline grafts2004In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 49, no 1, p. 13-22Article in journal (Refereed)
    Abstract [en]

    Thermosetting resins with semi-crystalline grafts have been synthesized. An amorphous resin with epoxide groups was first functionalized with hydroxyl groups using 2,2-bis(methylol) propionic acid, bis-MPA in bulk at 155 degreesC. Functionalization with bis-MPA was monitored using FT-IR, FT-Raman and SEC. The reaction was complete in 30 min. Grafts of poly(epsilon-caprolactone) were then grown from the hydroxyl functional resin and end capped with methacrylate groups. The polymerization Of epsilon-caprolactone, performed in bulk at 110 degreesC using Sn(Oct)(2), was characterized using H-1 NMR and SEC. The obtained molecular weights agreed well with theoretical values. The final end capping was performed using methacrylic anhydride, and monitored with SEC and H-1 NMR, which indicated full substitution. Two combs were synthesized with different arm lengths, DP 10 and 20, and the obtained M-W were close to calculated values. The complex viscosity was measured from low to high temperature for the crystalline resins, the amorphous resin and blends thereof. Rheological data show a rapid decrease in viscosity within a temperature change of 10-15 degreesC for the crystalline resins while the amorphous resin exhibited a slow softening. The blends exhibited a behavior in-between that of the crystalline and the amorphous resin. Films were prepared from the pure resins and the blends. The films were cured using UV irradiation. The comb architecture of these resins has advantages such as crystallinity, high molecular weight and low viscosity, facilitating leveling and resulting in smooth films. The final film properties varied with the ratio of crystalline to amorphous resin, where increase in the amount of crystalline resin correlated with increased the flexibility.

  • 417.
    Claisse, Antoine
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Physics.
    Van Uffelen, P.
    Towards the inclusion of open fabrication porosity in a fission gas release model2015In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 466, p. 351-356Article in journal (Refereed)
    Abstract [en]

    A model is proposed for fission product release in oxide fuels that takes into account the open porosity in a mechanistic manner. Its mathematical framework, assumptions and limitations are presented. It is based on the model for open porosity in the sintering process of crystalline solids. More precisely, a grain is represented by a tetrakaidecahedron and the open porosity is represented by a continuous cylinder along the grain edges. It has been integrated in the TRANSURANUS fuel performance code and applied to the first case of the first FUMEX project as well as to neptunium and americium containing pins irradiated during the SUPERFACT experiment and in the JOYO reactor. The results for LWR and FBR fuels are consistent with the experimental data and the predictions of previous empirical models when the thermal mechanisms are the main drivers of the release, even without using a fitting parameter. They also show a different but somewhat expected behaviour when very high porosity fuels are irradiated at a very low burn-up and at low temperature.

  • 418.
    Cobo Sanchez, Carmen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Inorganic and organic polymer-grafted nanoparticles: their nanocomposites and characterization2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanocomposites (NCs) have been widely studied in the past decades due to the promising properties that nanoparticles (NPs) offer to a polymer matrix, such as increased thermal stability and non-linear electrical resistivity. It has also been shown that the interphase between the two components is the key to achieving the desired improvements. In addition, polymer matrices are often hydrophobic while NPs are generally hydrophilic, leading to NP aggregation. To overcome these challenges, NPs can be surface-modified by adding specific molecules and polymers. In the present work, a range of organic and inorganic NPs have been surface-modified with polymers synthesized by atom transfer radical polymerization (ATRP) or surface-initiated ATRP (SI-ATRP).Cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) are highly crystalline NPs that can potentially increase the Young’s modulus of the NC. In this study, a matrix-free NC was prepared by physisorption of a block-copolymer containing a positively charged (quaternized poly(2-(dimethylamino)ethyl methacrylate), qPDMAEMA) and a thermo-responsive (poly di(ethylene glycol) methyl ether methacrylate, PDEGMA). The modified CNF exhibited a thermo-responsive, reversible behavior. CNCs were polymer-modified either via SI-ATRP or physisorbed with poly (butyl methacrylate) (PBMA) to improve the dispersion and interphase between them and a polycaprolactone (PCL) matrix during extrusion. The mechanical properties of the NCs containing CNC modified via SI-ATRP were superior to the reference and unmodified materials, even at a high relative humidity.Reduced graphene oxide (rGO) and aluminum oxide (Al2O3) are interesting for electrical and electronic applications. However, the matrices used for these applications, such as poly(ethylene-co-butyl acrylate) (EBA) and low density polyethylene (LDPE) are mainly hydrophobic, while the NPs are hydrophilic. rGO was modified via SI-ATRP using different chain lengths of PBMA and subsequently mixed with an EBA matrix. Al2O3 was modified with two lengths of poly(lauryl methacrylate) (PLMA), and added to LDPE prior to extrusion. Agglomeration and dispersion of the NCs were dependent on the lengths and miscibilities of the grafted polymers and the matrices. rGO-EBA NCs showed non-linear direct current (DC) resistivity upon modification, as the NP dispersion improved with increasing PBMA length. Al2O3-LDPE systems improved the mechanical properties of the NCs when low amounts of NPs (0.5 to 1 wt%) were added, while decreasing power dissipation on the material.Finally, PLMA-grafted NPs with high polymer quantities and two grafting densities in Al2O3 and silicon oxide (SiO2) nanoparticles were synthesized by de-attaching some of the silane groups from the surfaces, either by hydrolysis or by a mild tetrabutylammonium fluoride (TBAF) cleavage. These compounds were characterized and compared to the bulk PLMA, and were found to have very interesting thermal properties.

    The full text will be freely available from 2020-04-24 14:42
  • 419.
    Cobo Sanchez, Carmen
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Matrix-free Nanocomposites based on Poly(lauryl methacrylate)-Grafted Nanoparticles: Effect of Graft Length and Grafting DensityManuscript (preprint) (Other academic)
    The full text will be freely available from 2020-04-24 14:17
  • 420. Codan, L.
    et al.
    Casillo, S.
    Bäbler, Matthäus U.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Mazzotti, M.
    Phase diagram of a chiral substance exhibiting oiling out. 2. Racemic compound forming ibuprofen in water2012In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, no 11, p. 5298-5310Article in journal (Refereed)
    Abstract [en]

    This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. The two enantiomers crystallize as a racemic compound and exhibit a thermodynamically stable liquid-liquid phase separation (LLPS), which extends over the entire enantiomeric composition range. First, the generic phase behavior of racemic compound forming systems exhibiting a stable LLPS is derived by exploiting the consolidated knowledge of conglomerate forming systems obtained in the first part of this series. Below the onset temperature of the LLPS, the system behaves like a typical racemic compound forming system. As for conglomerate forming systems, the onset of the LLPS is found to occur through a ternary monotectic equilibrium, where a new, solute-rich liquid phase emerges inside each solid-solid-liquid phase region. Then, the ternary phase diagram of the ibuprofen/water system in the temperature range from 40 to 82 °C is presented together with the outcome of a thorough experimental investigation. Our theoretical considerations are in excellent agreement with experimental results.

  • 421. Codan, Lorenzo
    et al.
    Bäbler, Matthäus
    Institute of Process Engineering, ETH Zurich.
    Mazzotti, Marco
    Phase Diagram of a Chiral Substance Exhibiting Oiling Out in Cyclohexane2010In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, no 9, p. 4005-4013Article in journal (Refereed)
    Abstract [en]

    This work investigates the ternary phase diagram of the enantiomers of ethyl-2-ethoxy-3-(4-hydroxyphenyl)propanoate (EEHP) in cyclohexane. The enantiomers of EEHP form aconglomerate, and both the pure enantiomer and the racemic mixture exhibit stable oilingout in cyclohexane. Our analysis shows that the ternary phase diagram of such a system assumes a unique structural evolution around the onset temperature of oiling out; that is, we found that the onset of oiling out strictly occurs through the emergence of a second liquid phase of racemic composition. Furthermore, we found that the further evolution of the ternary phase diagram, i.e., above the onset temperature of oiling out, is dictated by the properties of the phase diagrams pure enantiomer/solvent and racemic mixture/solvent. Our theoretical considerations are in excellent agreement with experimental measurements of EEHP in cyclohexane. 

  • 422.
    Colson, Jerome
    et al.
    Univ Nat Resources & Life Sci Vienna, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulin, Austria..
    Pettersson, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Asaadi, Shirin
    Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, Vuorimiehentie 1, Espoo 02150, Finland..
    Sixta, Herbert
    Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, Vuorimiehentie 1, Espoo 02150, Finland..
    Nypelo, Tiina
    Chalmers Univ Technol, Dept Chem & Chem Technol, Kemigarden 4, S-41296 Gothenburg, Sweden..
    Mautner, Andreas
    Univ Vienna, Fac Chem, Inst Mat Chem & Res, Wahringer Str 42, A-1090 Vienna, Austria..
    Konnerth, Johannes
    Univ Nat Resources & Life Sci Vienna, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulin, Austria..
    Adhesion properties of regenerated lignocellulosic fibres towards poly (lactic acid) microspheres assessed by colloidal probe technique2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 532, p. 819-829Article in journal (Refereed)
    Abstract [en]

    In the field of polymer reinforcement, it is important to understand the interactions involved between the polymer matrix and the reinforcing component. This paper is a contribution to the fundamental understanding of the adhesion mechanisms involved in natural fibre reinforced composites. We report on the use of the colloidal probe technique for the assessment of the adhesion behaviour between poly(lactic acid) microspheres and embedded cross-sections of regenerated lignocellulosic fibres. These fibres consisted of tailored mixtures of cellulose, lignin and xylan, the amount of which was determined beforehand. The influence of the chemical composition of the fibres on the adhesion behaviour was studied in ambient air and in dry atmosphere. In ambient air, capillary forces resulted in larger adhesion between the sphere and the fibres. Changing the ambient medium to a dry nitrogen atmosphere allowed reducing the capillary forces, leading to a drop in the adhesion forces. Differences between fibres of distinct chemical compositions could be measured only on freshly cut surfaces. Moreover, the surface energy of the fibres was assessed by inverse gas chromatography. Compared to fibres containing solely cellulose, the presence of lignin and/or hemicellulose led to higher adhesion and lower surface energy, suggesting that these chemicals could serve as natural coupling agents between hydrophobic and hydrophilic components.

  • 423.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Chlorate cathodes and electrode design2014In: Encyclopedia of applied electrochemistry / [ed] R.F. Savinell,K. Ota,G. Kreysa, Springer, 2014, p. 175-181Chapter in book (Refereed)
  • 424.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Chlorate synthesis cells and technology2014In: Encyclopedia of applied electrochemistry / [ed] R.F. Savinell, K. Ota, G. Kreysa, Springer, 2014, p. 181-187Chapter in book (Refereed)
  • 425.
    Cornell, Ann
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Electrode reactions in the chlorate process2002Doctoral thesis, comprehensive summary (Other scientific)
  • 426.
    Cornell, Ann
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Simonsson, Daniel
    KTH, Superseded Departments, Chemical Engineering and Technology.
    The effect of addition of chromate on the hydrogen evolution reaction and on iron oxidation in hydroxide and chlorate solutions1992In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 37, no 10, p. 1873-1881Article in journal (Refereed)
    Abstract [en]

    The addition of chromate to the electrolyte has been shown in previous papers to hinder almost completely the electroreduction of hypochlorite, while the hydrogen evolution reaction can still proceed on the cathode surface. The effect of chromate on the latter reaction has been studied with cyclic voltammetry and by measuring polarization curves for iron electrodes in both chlorate and hydroxide electrolyte. For the sake of comparison, the investigations have also included the effects on the gold electrode in hydroxide solution. The results showed that the kinetics is changed in a way that decreases the differences in electrocatalytic activity between different electrode materials. Also, the innermost layer of the chromium hydroxide film seems to be the most active part in the HER. The chromate also affects the oxidation of the iron surface. A practical result of this is that the activity for the HER on corroded iron in chlorate electrolyte depends on whether the electrolyte contained chromate during the period of corrosion. The activation becomes much smaller if chromate is present.

  • 427.
    Cornell, Ann
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Simonsson, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ruthenium Dioxide as Cathode Material for Hydrogen Evolution in Hydroxide and Chlorate Solutions1993In: Chlor-Alkali and Chlorate Production/New Mathematical and Computational Methods in Electrochemical Engineering / [ed] T. Jeffrey, K. Ota, J. Fenton och H. Kawamoto, Pennington, New Jersey, USA: The Electrochemical Society , 1993, p. 191-Chapter in book (Refereed)
  • 428.
    Cornell, Ann
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Simonsson, Daniel
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Ruthenium Dioxide as Cathode Material for Hydrogen Evolution in Hydroxide and Chlorate Solutions1993In: Journal of The Electrochemical Society, Vol. 140, no 11, p. 3123-3129Article in journal (Refereed)
    Abstract [en]

    Ruthenium dioxide as electrocatalyst on an activated cathode for chlorate production was investigated with respect toits activity towards hydrogen evolution, hypochlorite reduction, and chlorate reduction, respectively. Investigations weremade in the presence, as well as in the absence, of a chromium hydroxide film in 1M NaOH and in typical chlorateelectrolyte. Low overvoltages for hydrogen evolution were found and, at technical current densities, an effect of catalystcoating thickness. Commercial DSA® electrodes with RuO2 as the active compound were tested as cathodes and were lessactive but more stable than the coatings produced by us. Hypochlorite and chlorate were reduced in the absence ofchromate, chlorate reduction being fast on ruthenium dioxide compared to the other electrode materials and by far thedominating cathodic reaction in chlorate electrolyte without chromate and hypochlorite at 70°C, 3 kA/m2

  • 429. Coronado, Christian Rodriguez
    et al.
    Tuna, Celso Eduardo
    Zanzi, Rolando
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Vane, Lucas F.
    Silveira, Jose Luz
    Development of a thermoeconomic methodology for the optimization of biodiesel production-Part I: Biodiesel plant and thermoeconomic functional diagram2013In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 23, p. 138-146Article in journal (Refereed)
    Abstract [en]

    This work developed a methodology that uses the thermoeconomic functional diagram applied for allocating the cost of products produced by a biodiesel plant. The first part of this work discusses some definitions of exergy and thermoeconomy, with a detailed description of the biodiesel plant studied, identification of the system functions through Physical Diagram, calculation of the irreversibilities of the plant, construction of the Thermoeconomic Functional Diagram and determination of the expressions for the plant's exergetic functions. In order to calculate the exergetic increments and the physical exergy of certain flows in each step, the Chemical Engineering Simulation Software "HYSYS 3.2" was used. The equipments that have the highest irreversibilities in the plant were identified after the exergy calculation. It was also found that the lowest irreversibility in the system refers to the process with a molar ratio of 6:1 and a reaction temperature of 60 degrees C in the transesterification process. In the second part of this. work (Part II), it was calculated the thermoeconomic cost of producing biodiesel and related products, including the costs of carbon credits for the CO2 that is not released into the atmosphere, when a percentage of biodiesel is added to the petroleum diesel used by Brazil's internal diesel fleet (case study).

  • 430. Cozzolino, Carlo A.
    et al.
    Campanella, Gaetano
    Ture, Hasan
    Olsson, Richard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Farris, Stefano
    Microfibrillated cellulose and borax as mechanical, O-2-barrier, and surface-modulating agents of pullulan biocomposite coatings on BOPP2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 143, p. 179-187Article in journal (Refereed)
    Abstract [en]

    Multifunctional composite coatings on bi-oriented polypropylene (BOPP) films were obtained using borax and microfibrillated cellulose (MFC) added to the main pullulan coating polymer. Spectroscopy analyses suggested that a first type of interaction occurred via hydrogen bonding between the C-6-OH group of pullulan and the hydroxyl groups of boric acid, while monodiol and didiol complexation represented a second mechanism. The deposition of the coatings yielded an increase in the elastic modulus of the entire plastic substrate (from similar to 2 GPa of the neat BOPP to similar to 3.1 GPa of the P/B+/MFC-coated BOPP). The addition of MFC yielded a decrease of both static and kinetic coefficients of friction of approximately 22% and 25%, respectively, as compared to the neat BOPP. All composite coatings dramatically increased the oxygen barrier performance of BOPP, especially under dry conditions. The deposition of the high hydrophilic coatings allowed to obtain highly wettable surfaces (water contact angle of similar to 18 degrees).

  • 431. Cracknell, R. F.
    et al.
    Head, R. A.
    McAllister, L. J.
    Andrae, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Octane sensitivity in gasoline fuels containing nitro-alkanes: A possible means of controlling combustion phasing for HCCI2009In: SAE technical paper series, ISSN 0148-7191Article in journal (Refereed)
    Abstract [en]

    Addition of nitroalkanes to gasoline is shown to reduce the octane quality. The reduction in the Motor Octane Number (MON) is greater than the reduction in the Research Octane Number (RON). In other words addition of nitroalkanes causes an increase in octane sensitivity. The temperature of the compressed air/fuel mixture in the MON test is higher then in the RON test. Through chemical kinetic modelling, we are able to show how the temperature dependence of the reactions responsible for break-up of the nitroalkane molecule can lead to an increase in octane sensitivity. Results are presented from an Homogenous Charge Compression Ignition (HCCI) engine with a homogeneous charge in which the air intake temperature was varied. When the engine was operated on gasoline-like fuels containing nitroalkanes, it was observed that the combustion phasing was much more sensitive to the air intake temperature. This suggests a possible means of controlling combustion phasing for HCCI.

  • 432.
    Crawford, James
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Moreno, Luis
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Neretnieks, Ivars
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Harmonisation of site characterisation and performance assessment modelling - The relative importance of surface sorption and matrix interaction phenomena2004In: Scientific Basis For Nuclear Waste Management XXVII / [ed] Oversby, VM; Werme, LO, 2004, Vol. 807, p. 551-556Conference paper (Refereed)
    Abstract [en]

    In the context of geological repositories for nuclear waste disposal, the goal of site characterisation (SC) is to obtain input data that can later be used as a basis for performance assessment calculations (PA). Performance assessment is required to give an indication as to whether the repository will behave as intended over the geological timescales relevant for risk analysis. Processes that may be important in a PA setting for constraining radionuclide transport may not necessarily be dominating, or indeed may not even be observable during SC investigations. In this paper it is shown that the migration of sorbing tracers is governed largely by surface sorption phenomena in typical SC-type field experiments whereas in a PA scenario, matrix interaction instead can be expected to play an overwhelmingly important role. This study uses data and settings that are representative for fractured rocks in Sweden, but the method used and the conclusions may have more general applicability.

  • 433. Croker, D. M.
    et al.
    Davey, R. J.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Univ Limerick, Mat & Surface Sci Inst, Dept Chem & Environm Sci.
    Seaton, C. C.
    Nucleation in the p-toluenesulfonamide/triphenylphosphine oxide co-crystal system2013In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, no 8, p. 3754-3762Article in journal (Refereed)
    Abstract [en]

    Nucleation has been studied in pure co-crystal and mixed co-crystal phase regions of the ternary phase diagram (TPD) in acetonitrile at 20 C using cooling crystallization experiments. Direct nucleation of each of the co-crystal phases in this system was independently observed in regions of the TPD where each is stable. In mixed regions, regions where either a co-crystal and a coformer, or both co-crystals, are stable, the phase that initially nucleated was a function of the mass composition in that region. The relative amount of each phase nucleating could be controlled by adjusting the relative mass fraction of each component. The kinetic return to equilibrium was also observed as the systems were held over time, with the selected mass fractions always returning to the equilibrium dictated by the TPD after 24 h

  • 434. Croker, D. M.
    et al.
    Davey, R. J.
    Rasmuson, Åke Christoffer
    Univ Limerick, Mat & Surface Sci Inst, Dept Chem & Environm Sci.
    Seaton, C. C.
    Solution mediated phase transformations between co-crystals2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 11, p. 2044-2047Article in journal (Refereed)
    Abstract [en]

    A solution mediated transformation between two co-crystal phases has been observed for the p-toluensulfonamide-triphenylphosphine oxide co-crystal system. This system has two known co-crystals with 1 : 1 and 3 : 2 stoichiometry respectively, and the ternary phase diagram (TPD) for the system has been determined in acetonitrile previously. By manipulating the solution composition in this solvent to a region of the TPD where the 1 : 1 co-crystal is stable, the 3 : 2 co-crystal could be observed to convert to the 1 : 1 co-crystal. The corresponding transformation was true for the 1 : 1 co-crystal in a region of the TPD where the 3 : 2 co-crystal is stable; the 1 : 1 co-crystal converted to the 3 : 2 co-crystal.

  • 435. Croker, D. M.
    et al.
    Kelly, D. M.
    Horgan, D. E.
    Hodnett, B. K.
    Lawrence, S. E.
    Moynihan, H. A.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. University of Limerick.
    Demonstrating the Influence of Solvent Choice and Crystallization Conditions on Phenacetin Crystal Habit and Particle Size Distribution2015In: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 19, no 12, p. 1826-1836Article in journal (Refereed)
    Abstract [en]

    Phenacetin was used as a model pharmaceutical compound to investigate the impact of solvent choice and crystallization conditions on the crystal habit and size distribution of the final crystallized product. The crystal habit of phenacetin was explored using crash-cooling crystallization (kinetically controlled) and slow evaporative crystallization (thermodynamically controlled) in a wide range of organic solvents. In general, a variety of needle-type shapes (needles, rods, or blades) were recovered from fast-cooling crystallizations, in contrast to hexagonal blocks obtained from slow evaporative crystallizations. The solubility of phenacetin was measured in five solvents from 10-70 degrees C to allow for the design of larger-scale crystallization experiments. Supersaturation and the nucleation temperature were independently controlled in isothermal desupersaturation experiments to investigate the impact of each on crystal habit and size. The crystal size (needle cross-sectional area) decreased with increasing supersaturation because of higher nucleation rates at higher supersaturation, and elongated needles were recovered: Increasing the nucleation temperature resulted in the production of larger crystals with decreased needle aspect ratios. Antisolvent phenacetin crystallizations were developed for three solvent/antisolvent systems using four different antisolvent addition rates to simultaneously probe the crystal habit and size of the final product. In general, increasing the antisolvent addition rate, associated with increased rate of generation of supersaturation, resulted in the production of shorter needle crystals.

  • 436. Croker, D. M.
    et al.
    Rasmuson, Åke Christoffer
    University of Limerick.
    Isothermal suspension conversion as a route to cocrystal production: One-pot scalable synthesis2014In: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 18, no 8, p. 941-946Article in journal (Refereed)
    Abstract [en]

    Isothermal suspension conversion is presented as a suitable method for the manufacture of pure cocrystal products once the ternary phase diagram (TPD) for the cocrystal system in the desired solvent is available. One:one and 3:2 cocrystals of p-toluenesulphonamide/triphenylphosphine oxide were produced in acetonitrile and dichloromethane using this method. Eight individual batches of product were prepared with complete conversion to pure product achieved in seven batches. Product recovery (77-99%), reaction conversion (17-89%), and volumetric productivity (0.03-0.63 g/cm(3)) were calculated for each product batch. These parameters are essentially determined by the batch operating mass fraction composition selected from the TPD, allowing for tailoring of processing conditions to suit process requirements and capabilities by careful selection of the optimum operating mass fraction composition.

  • 437.
    Cunha, Ana Gisela
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Larsson, Per Tomas
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. INNVENTIA AB, Sweden.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 4, p. 2773-2787Article in journal (Refereed)
    Abstract [en]

    Moisture sorption decreases dimensional stability and mechanical properties of polymer matrix biocomposites based on plant fibers. Cellulose nanofiber reinforcement may offer advantages in this respect. Here, wood-based nanofibrillated cellulose (NFC) and bacterial cellulose (BC) nanopaper structures, with different specific surface area (SSA), ranging from 0.03 to 173.3 m(2)/g, were topochemically acetylated and characterized by ATR-FTIR, XRD, solid-state CP/MAS C-13-NMR and moisture sorption studies. Polymer matrix nanocomposites based on NFC were also prepared as demonstrators. The surface degree of substitution (surface-DS) of the acetylated cellulose nanofibers is a key parameter, which increased with increasing SSA. Successful topochemical acetylation was confirmed and significantly reduced the moisture sorption in nanopaper structures, especially at RH = 53 %. BC nanopaper sorbed less moisture than the NFC counterpart, and mechanisms are discussed. Topochemical NFC nanopaper acetylation can be used to prepare moisture-stable nanocellulose biocomposites.

  • 438.
    Cunha, Gisera
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. INRA, Biopolymeres Interact & Assemblages, France.
    Mougel, Jean-Bruno
    Cathala, Bernard
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Capron, Isabelle
    Preparation of Double Pickering Emulsions Stabilized by Chemically Tailored Nanocelluloses2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 31, p. 9327-9335Article in journal (Refereed)
    Abstract [en]

    Nanocelluloses are bio-based nanoparticles of interest as stabilizers for oil-in-water (o/w) Pickering emulsions. In this work, the surface chemistry of nanocelluloses of different length, nanofibrillated cellulose (NFC, long) and cellulose nanocrystals (CNC, short), was successfully tailored by chemical modification with lauroyl chloride (C12). The resulting nanofibers were less hydrophilic than the original and able to stabilize water-in-oil (w/o) emulsions. The combination of the two types of nanocelluloses (C12-modified and native) led to new surfactant-free oil-in-water-in-oil (o/w/o) double emulsions stabilized by nanocellulose at both interfaces. Characterization was performed with respect to droplet size distribution, droplet stability over time, and stability after centrifugation. Nanocellulose-based Pickering emulsions can be designed with a substantial degree of control, as demonstrated by the stability of the chemically tailored NFC double emulsions. Furthermore, it was demonstrated that increased nanofiber length leads to increased stability.

  • 439.
    Cuvilas, Carlos Alberto
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mild Wet Torrefaction and Characterization of Woody Biomass from Mozambique for Thermal Applications2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mozambique has vast forestry resources and also considerable biomass waste material such as bagasse, rice husks, sawdust, coconut husks and shells, cashew nut shell and lump charcoal waste. The potential of the total residues from the agricultural sector and the forest industry is estimated to be approximately 13 PJ. This amount of energy covers totally the production of charcoal which amounted to approximately 12.7 PJ in 2006. Although biomass is an attractive renewable source of energy, it is generally difficult to handle, transport, storage and use due to its lower homogeneity, its lower energy density and the presence of non-combustible inorganic constituents, which leads to different problems in energy conversion units such as deposition, sintering, agglomeration, fouling and corrosion. Therefore, a pretreatment of the biomass to solve these problems could lead to a change of current biomass utilization situation. The aim of this study is to convert Mozambican woody biomass residue into a solid biochar that resembles low-grade coal.

    In this work the current energy situation in Mozambique has been reviewed, and the available and potential renewable sources including residues from agricultural crops and forest industry as energy have been assessed. It was found that the country is endowed with great potential for biofuel, solar, hydro and wind energy production. However, the production today is still far from fulfilling the energy needs of the country, and the majority of people are still not benefiting from these resources. Charcoal and firewood are still the main sources of energy and will continue to play a very important role in the near future. Additionally, enormous amounts of energy resources are wasted, especially in the agricultural sector. These residues are not visible on national energy statistics. The chemical composition and the fuelwood value index (FVI) showed that by failing to efficiently utilise residues from Afzelia quanzensis, Millettia stuhlmannii and Pterocarpus angolensis, an opportunity to reduce some of the energy related problems is missed. An evaluation of effect of a mild wet torrefaction pretreatment showed that the chemical composition of the biochar is substantially different than the feedstock. The use of diluted acid as catalysts improves the biochar quality, namely in terms of the energy density and ash characteristics; however, the increment of the S content in the final product should be considered for market acceptance (because the fuels have a maximum allowance for S concentration). The thermal behaviour of the untreated and treated biomass was also investigated. The pyrolytic products of umbila and spruce were affected by the treatment and catalyst in terms of yield and composition of the vapours.

  • 440.
    Cömert, Engin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Utvärdering av karboniserad LDPE som egenskapsförbättrande tillsats i nya LDPE-filmer2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Previous research has shown that with the assistance of a specially formed microwave oven you can degrade low density polyethylene (LDPE) to chemicals with more value, so this project will try to reform plastic waste (LDPE) to a product with more value.

    Being able to recycle plastic is a question that has grown these past years and is still growing. As things stand there is an interest in being able to produce plastics that can be recycled. Because plastics lose some of their mechanical properties every time they are heated the companies who produce them find it easier and cheaper to just use new plastic. Therefore, to be able to produce a plastic which does not lose its mechanical properties is something that is being strived for. Carbon dots is a new kind of nanomaterial that has fascinating properties and research on it and its properties has been done during the last 10 years. During this project the main focus will therefore be to evaluate whether LDPE can be carbonized to carbon dot like materials and whether addition of these affects the mechanical properties of new LDPE products.

    By using the special microwave, the synthesis of carbon dots was successful. In addition, solid particles we gained from LDPE. The structural properties of the carbon dots and solid particles were analysed by using FT-IR, NMR and XRD. There was also an analysis on the particle sizes which was done by using DLS and morphological evaluation which was performed by SEM. The synthesized particles were also put into TGA to evaluate their thermal stability. The synthesis was successful, and you could see a change in the particles structure because new functional groups could be found by using FT-IR, NMR and XRD. The particle size was also measured, and the consensus was that the particles were coarse and not that homogenous.

    Making of the composites with the carbon dots and solid particles is also something that was successfully done. The composites contained 0.5 wt-% of synthesized carbon dots and 99.5 wt-% of LDPE powder and another one where 2.5 wt-% of synthesized carbon dots was mixed with 97.5 wt-% of LDPE powder. The solid particle composites were created by mixing 5 wt-% and 10 wt-% solid particles mixed with 95 wt-% and 90 wt-% of LDPE powder.

    The mechanical properties were analysed with a tensile testing machine, the result that was retrieved from the machine was that the films made of the composites with DP gave a stiffer material than the film made only by LDPE. The composite films with FP gave a much higher modulus than the other films made by addition of DP. The results show that the films with FP were also a lot stiffer than the film with only LDPE. The conclusion is that you can use this method to create a material that is stronger and stiffer.

  • 441.
    Dahlin, Oskar
    KTH, School of Chemical Science and Engineering (CHE).
    Ecological Analysis of Hydrogen Production by Photovoltaic Electrolysis2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 442.
    Dahlin, Sandra
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lantto, Cornelia
    Luleå University of Technology, Knightec AB.
    Englund, Johanna
    Chalmers University of Technology.
    Westerberg, Björn
    Scania CV.
    Regali, Francesco
    Scania CV.
    Skoglundh, Magnus
    Chalmers University of Technology.
    Pettersson, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Chemical aging of Cu-SSZ-13 SCR catalysts for heavy-duty vehicles –Influence of sulfur dioxide2018In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 320, p. 72-83Article in journal (Refereed)
    Abstract [en]

    Selective catalytic reduction of nitrogen oxides is an efficient technique for emission abatement in heavy-dutyvehicles. Cu-SSZ-13 SCR catalysts are more active than vanadium-based catalysts at low temperatures, but aremore sensitive to deactivation by sulfur. Consequently, there is a need to study poisoning by sulfur for thiscatalyst material. This experimental investigation focuses on the effect of sulfur on the low-temperature per-formance of Cu-SSZ-13 SCR catalysts. The effect of sulfur exposure temperature, and the influence of the NO 2 /NO x ratio, are considered and two different regeneration temperatures are compared. In addition, catalystsamples from an engine-aged catalyst are evaluated. The SO 2 exposure temperature is shown to have an im-portant impact on the deactivation of the Cu-SSZ-13 catalyst. The lowest sulfur exposure temperature (220 °C)results in the most severe deactivation, while the highest temperature during sulfur exposure (400 °C) results inthe lowest degree of deactivation. This was found to be related to the amount of sulfur on the catalyst.Additionally, SO 2 exposure was shown to decrease the N 2 O selectivity. The engine-aged catalyst has a decreasedperformance in terms of both decreased activity and increased N 2 O selectivity. For this catalyst, impurities fromfuel and engine-oil can play a role in the deactivation. Different deactivation mechanisms are seen for the lab-and engine-aged catalysts.

  • 443.
    Dahlin, Sandra
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Nilsson, Marita
    Backstrom, Daniel
    Bergman, Susanna Liljegren
    Bengtsson, Emelie
    Bernasek, Steven L.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology. Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, South Africa.
    Multivariate analysis of the effect of biodiesel-derived contaminants on V2O5-WO3/TiO2 SCR catalysts2016In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 183, p. 377-385Article in journal (Refereed)
    Abstract [en]

    This study investigates the effect of biodiesel-derived contaminants on vanadia-based NH3-SCR catalysts in heavy-duty exhaust aftertreatment. The aim was to study, not only the effect of single contaminants on the catalyst performance, but also of possible interaction effects between poisons. The effect of six potential catalyst poisons (Na, K, Mg, P, S and Zn) was evaluated using an experimental design and multivariate data analysis. Monolithic V2O5-WO3/TiO2 catalysts were subjected to accelerated laboratory-scale aging, where the six contaminants were fed simultaneously using a wet impregnation method. In addition to NO conversion tests, the catalysts were characterized by means of ICP-OES, SEM-EDX, XPS, N-2 physisorption and NH3-TPD. The lab-aged samples were compared to fresh and vehicle-aged catalysts. The accelerated aging method showed good reproducibility and gave rise to surface compounds similar to those found in vehicle-aged catalysts. Despite plausible differences regarding penetration depth of the contaminants into the walls of the catalyst, the aging method appears to be an efficient way to point out significant chemical poisons. The model obtained from the experimental design was found to correlate well with the experimental data and can therefore be used to predict effects of the various poisons and poison interactions. Significant effects on the NOx conversion were found for P, S, Na, Mg and K as well as for the interactions P x Na, P x K and S x Na. A poisoning effect was found for Mg, Na, K, P x K, and P x Na, where Na and K exhibited the strongest poisoning effect. The deactivating effect of alkali was lowered in the presence of phosphorus and sulfur, which is explained by the formation of phosphates and sulfates, preventing the interaction of the alkali metals with the vanadia active sites.

  • 444. Dahlquist, Erik
    et al.
    Mirmoshtaghi, Guilnaz
    Larsson, Eva K.
    Thorin, Eva
    Yan, Jinyue
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Liliedahl, Truls
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Dong, C.
    Hu, X.
    Lu, Q.
    Modelling and simulation of biomass conversion processes2015In: 2013 8TH EUROSIM CONGRESS ON MODELLING AND SIMULATION (EUROSIM), 2015, p. 506-512Conference paper (Refereed)
    Abstract [en]

    By utilizing biomass gasification, the energy content of the biomass can be utilized to produce gas to be used for cogeneration of heat and power as well as other energy carriers such as fuels for vehicles. The concept is suitable for application to existing CHP plants as well as for utilizing spent liqour in small scale pulp and paper mills. The introduction would enable flexible energy utilization, use of problematic fuels as well as protects the environment by e.g. avoiding the release of toxic substances. In this paper, the possibilities to develop this concept is discussed. In this paper we compare different gasification processes with respect to what gas quality we get, and how the gasification can be modelled using different modelling approaches, and how these can be combined. Results from simulations are compared to experimental results from pilot plant operations in different scales and with different processes like CFB and BFB Technologies, athmospheric and pressurized, and using steam, air and oxygen as oxidizing media.

  • 445.
    Dai, Jing
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ferreira Fernandes, Ricardo Manuel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Univ Porto, CIQUP, Dept Chem & Biochem, Fac Sci, P-4169007 Porto, Portugal..
    Regev, Oren
    Ben Gurion Univ Negev, Dept Chem Engn, IL-84105 Beer Sheva, Israel.;Ben Gurion Univ Negev, Ilse Katz Inst Nanotechnol, IL-84105 Beer Sheva, Israel..
    Marques, Eduardo F.
    Univ Porto, CIQUP, Dept Chem & Biochem, Fac Sci, P-4169007 Porto, Portugal..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Dispersing Carbon Nanotubes in Water with Amphiphiles: Dispersant Adsorption, Kinetics, and Bundle Size Distribution as Defining Factors2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 42, p. 24386-24393Article in journal (Refereed)
    Abstract [en]

    Debundling and dispersing single-walled carbon nanotubes (SWNTs) is essential for applications, but the process is not well understood. In this work, aqueous SWNT dispersions were produced by sonicating pristine SWNT powder in the presence of an amphiphilic triblock copolymer (Pluronic F127) as dispersant. Upon centrifugation, one obtains a supernatant with suspended individual tubes and thin bundles and a precipitate with large bundles (and impurities). In the supernatant, that constitutes the final dispersion, we determined the dispersed SWNT concentration by thermogravi-metric analysis (TGA) and UV-vis spectroscopy, and the dispersant concentration by NMR The fraction of dispersant adsorbed at the SWNT surface was obtained by H-1 diffusion NMR Sigmoidal dispersion curves recording the concentration of dispersed SWNTs as a function of supernatant dispersant concentration were obtained at different SWNT loadings and sonication times. As SWNT bundles are debundled into smaller and smaller ones, the essential role of the dispersant is to sufficiently quickly cover the freshly exposed surfaces created by shear forces induced during sonication. Primarily kinetic reasons are behind the need for dispersant concentrations required to reach a substantial SWNT concentration. Centrifugation sets the size threshold below which SWNT particles are retained in the dispersion and consequently determines the SWNT concentration as a function of sonication time.

  • 446. Daianova, L.
    et al.
    Dotzauer, E.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Evaluation of a regional bioenergy system with local production of biofuel for transportation, integrated with a CHP plant2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 739-749Article in journal (Refereed)
    Abstract [en]

    The share of renewable liquid fuels (ethanol, fatty acid methyl ester, biogas, and renewable electricity) in the total transportation fuel in Sweden, has increased by the end of 2009 to such level that e.g. domestic bioethanol production is unable to satisfy current ethanol fuel demand. Regional small-scale ethanol production can assist the region in covering the regional needs in transport fuel supply. Current case study system includes the production of ethanol, biogas, heat and power from locally available cereals straw. A mixed integer programming (MIP) model is developed for cost optimization of regional transport fuel supply (ethanol, biogas and petrol). The model is applied for two cases, one when ethanol production plant is integrated with an existing CHP plant (polygeneration), and one with a standalone ethanol production plant. The optimization results show that for both cases the changes in ethanol production costs have the biggest influence on the costs for supplying regional passenger car fleet with transport fuel. Petrol fuel price and straw production costs have also a significant effect on costs for supplying cars with transport fuel for both standalone ethanol production and integrated production system. By integrating the ethanol production process with a CHP plant, the costs for supplying regional passenger car fleet with transport fuel can be cut by 31%, from 150 to 104 (sic)/MW h fuel, which should be compared with E5 costs of 115 E/MW h (excl VAT).

  • 447. D'Alessandro, Fabrizio
    et al.
    Pacchiarotta, Giovanna
    Rubino, Alberto
    Sperandio, Mauro
    Villa, Pierluigi
    Carrera, Arturo Manrique
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Fakhrai, Reza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Marra, Gianluigi
    Congiu, Annalisa
    Lean Catalytic Combustion for Ultra-low Emissions at High Temperature in Gas-Turbine Burners2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, p. 136-143Article in journal (Refereed)
    Abstract [en]

    Catalytic systems for methane combustion, with Rh and Pt in a BaZrO3-based perovskite, were synthesized at the University of L'Aquila and tested at close to industrial conditions at the KTH Energy Centre in Stockholm. Because of the resistance to high temperature of BaZrO3 (up to similar to 2600 degrees C), such systems are suitable for resolving stability problems frequently encountered with high-temperature operations. Furthermore, these perovskites contain the noble metal in a high oxidation state, giving rise to very active compounds. They also result in ultra-low emissions, compatible with legislation in such places as southern California and Japan.

  • 448.
    Dalla-Santa, Oscar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Catalyzed Synthesis of Aromatic Esters2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    The full text will be freely available from 2020-06-04 16:54
  • 449. Danielsson, Carl-Ola
    et al.
    Dahlkild, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Velin, Anna
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    A Model for the Enhanced Water Dissociation On Monopolar Membranes2009In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 54, no 11, p. 2983-2991Article in journal (Refereed)
    Abstract [en]

    A model for the enhanced water dissociation that takes place at the solution/membrane interface in electromembrane processes is presented. The mechanisms behind the enhanced water dissociation are poorly understood and therefore a semi-empirical approach is suggested. The enhanced water dissociation is introduced as a heterogeneous surface reaction similar to the well established Butler–Volmer law for electrode reactions. In the model there are two parameters that need to be determined through experiments. A 1D diffusion boundary layer problem is presented and solved in order to show that a sufficient rate of water dissociation can be obtained with the model. The advantage of the presented model is that it can easily be incorporated into simulations of electromembrane processes such as electrodialysis, electrodeionization and electropermutation. The influence of the enhanced water dissociation on these processes can then be studied.

  • 450. Danielsson, Carl-Ola
    et al.
    Dahlkild, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Velin, Anna
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Modeling Continuous Electropermutation with Effects of Water Dissociation Included2010In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 56, no 9, p. 2455-2467Article in journal (Refereed)
    Abstract [en]

    The repeating unit consisting of a cell pair of one concentrate and one feed compartment of an electropermutation stack is modeled. Both the feed and the concentrate compartments are filled with an ion-exchange textile material. Enhanced water dissociation taking place at the surface of the membrane is included in the model as a hetrogeneous surface reaction. Results from simulations of nitrate removal for drinking water production are presented and comparisons with previous experimental results are made. The influence of both conductive and inert textile spacers on the process is investigated via simulations

6789101112 401 - 450 of 2474
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf