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  • 1.
    Aasa, Jenny
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Törnqvist, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Abramsson-Zetterberg, Lilianne
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. National Food Agency, Sweden.
    Measurement of micronuclei and internal dose in mice demonstrates that 3-monochloropropane-1,2-diol (3-MCPD) has no genotoxic potency in vivo2017Inngår i: Food and Chemical Toxicology, ISSN 0278-6915, E-ISSN 1873-6351, Vol. 109, 414-420 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study 3-monochloropropane-1,2-diol (3-MCPD), a compound that appears as contaminant in refined cooking oils, has been studied with regard to genotoxicity in vivo (mice) with simultaneous measurement of internal dose using state-of-the-art methodologies. Genotoxicity (chromosomal aberrations) was measured by flow cytometry with dual lasers as the frequency of micronuclei in erythrocytes in peripheral blood from BalbC mice intraperitoneally exposed to 3-MCPD (0, 50, 75, 100, 125 mg/kg). The internal doses of 3-MCPD in the mice were calculated from N-(2,3-dihydroxypropyl)-valine adducts to hemoglobin (Hb), quantified at very low levels by high-resolution mass spectrometry.

    Convincing evidence for absence of genotoxic potency in correlation to measured internal doses in the mice was demonstrated, despite relatively high administered doses of 3-MCPD. The results are discussed in relation to another food contaminant that is formed as ester in parallel to 3-MCPD esters in oil processing, i.e. glycidol, which has been studied previously by us in a similar experimental setup. Glycidol has been shown to be genotoxic, and in addition to have ca. 1000 times higher rate of adduct formation compared to that observed for 3-MCPD. The conclusion is that at simultaneous exposure to 3-MCPD and glycidol the concern about genotoxicity would be glycidol.

  • 2.
    Abdi, Adel Hirmand
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Key aspects in winter highway operation and maintenance2010Rapport (Annet vitenskapelig)
  • 3.
    Achtel, Christian
    et al.
    Friedrich Schiller University of Jena.
    Heinze, Thomas
    Friedrich Schiller University of Jena.
    Homogenous modification of cellulose in the new solvent triethyloctylammonium chloride in combination with organic liquids2016Inngår i: The 7th Worskshop on Cellulose, Regenerated Cellulose and Cellulose Derivatives, 2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Recently, it has been demonstrated that triethyloctylammonium chloride (N2228Cl) bears great properties as cellulose solvent both as melt and in combination with organic solvents (Kostag et al. 2013; Kostag et al. 2014). On one hand, N2228Cl and N,N-dimethylacetamide (DMAc) dissolve cellulose within 2 h without prior activation of the polysaccharide. On the other, N2228Cl unexpectedly dissolves cellulose in the presence of acetone, which typically is known as precipitation agent for cellulose. On very recent studies, the novel solvent was applied for tosylation, acetylation and silylation of cellulose (Achtel 2016). These types of reactions were chosen, because tosylcellulose is an important intermediate for nucleophilic displacement reaction with cellulose, cellulose acetates are of industrial interest, and silylation of cellulose is commonly used to achieve products that form ultrathin films by spin-coating useful as model surface. The reactions were studied under different conditions and the resulted degree of substitutions (DS) were compared with values obtained in common cellulose solvents (LiCl/DMAc, DMSO/TBAF or ionic liquids).

  • 4. Adia, Madina Mohamed
    et al.
    Emami, Seyedeh Noushin
    Byamukama, Robert
    Faye, Ingrid
    Borg-Karlson, Anna-Karin
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Antiplasmodial activity and phytochemical analysis of extracts from selected Ugandan medicinal plants2016Inngår i: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 186, 14-19 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ethnopharmacological relevance: Resistance of the parasites to known antimalarial drugs has provided the necessity to find new drugs from natural products against malaria. The aim of the study was to evaluate the in vitro antiplasmodial activity of some plants used by Traditional Medical Practitioners (TMPs) of Prometra and Rukararwe in malaria treatment in Uganda to provide scientific proof of the efficacies claimed by these Herbalists. Materials and methods: The air dried samples of Clerodendrum rotundifolium (leaves), Microglossa pyrifolia (leaves), Momordica foetida (leaves) and Zanthoxylum chalybeum (stem bark) used for malaria treatment by TMPs were successively extracted with ethyl acetate, methanol and water to yield twelve extracts. The extracts were tested against the chloroquine-sensitive (NF54) and chloroquine-resistant (FCR3) Plasmodium falciparum strains in vitro using the micro Mark III test which is based on assessing the inhibition of schizont maturation. A compound A was extracted and purified from the stem bark of Z. chalybeum and its structure was identified and confirmed by spectroscopic methods. Results: Most of the extracts tested (92%) showed an antiplasmodial activity with IC50 < 50 mu g/mL. In spite of successive extractions with different solvents, potent anti-plasmodial activity (IC50 < 5 mu g/mL) was observed in the ethyl acetate, methanol and aqueous extracts of M. pyrifolia and C. rotundifolium. Preferential enrichments of activity into water (IC50 < 15 mu g/mL) and Ethyl acetate (IC50 < 5 mu g/mL) were seen in the case of M. foetida and Z chalybeum respectively. The most active extracts were from C rotundifolium and M. pyrifolia with IC50 values less than 2 mu g/mL. Phytochemical analysis of the extracts revealed the presence of saponins, tannins, flavonoids, alkaloids and cardiac glycocides. Fagaramide isolated from Z chalybeum had a higher activity (IC50 2.85 mu g/mL) against the chloroquine-resistant strain than against the chloroquine-senstive (IC50 16.6 mu g/mL) strain used in the study. Conclusion: The plant extracts analysed in this study presented an average antiplasmodial activity (58%). This study revealed for the first time the antiplasmodial activity of the plant C. rotundofolium. It's the first time the compound fagaramide (N-isobutyl-3-(3,4-methylene dioxyphenyl) - 2E-propenamide) has been isolated from Z. chalybeum as one of the compounds that contribute to the activity of this plant against P. falciparum.

  • 5.
    Ahlkvist, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Formic and Levulinic Acid from Cellulose via Heterogeneous Catalysis2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The chemical industry of today is under increased pressure to develop novel green materials, bio-fuels as well as sustainable chemicals for the chemical industry. Indeed, the endeavour is to move towards more eco-friendly cost efficient production processes and technologies and chemical transformation of renewables has a central role considering the future sustainable supply of chemicals and energy needed for societies. In the Nordic countries, the importance of pulping and paper industry has been particularly pronounced and the declining European demand on these products as a result of our digitalizing world has forced the industry to look at alternative sources of revenue and profitability. In this thesis, the production of levulinic and formic acid from biomass and macromolecules has been studied. Further, the optimum reaction conditions as well as the influence of the catalyst and biomass type were also discussed.

    Nordic sulphite and sulphate (Kraft) cellulose originating from two Nordic pulp mills were used as raw materials in the catalytic synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice used in this study was a macro-porous, cationic ion-exchange resin, Amberlyst 70, for which the optimal reaction conditions leading to best yields were determined. Cellulose from Nordic pulp mills were used as raw materials in the catalytic one-pot synthesis of ‘green’ levulinic and formic acid. The kinetic experiments were performed in a temperature range of 150–200 °C and an initial substrate concentration regime ranging from 0.7 to 6.0 wt %. It was concluded that the most important parameters in the one-pot hydrolysis of biomass were the reaction temperature, initial reactant concentration, acid type as well as the raw material applied. The reaction route includes dehydration of glucose to hydroxymethylfurfural as well as its further rehydration to formic and levulinic acids. The theoretical maximum yield can hardly be obtained due to formation of humins. For this system, maximum yields of 59 mol % and 68 mol % were obtained for formic and levulinic acid, respectively. The maximum yields were separately obtained in a straight-forward conversion system only containing cellulose, water and the heterogeneous catalyst. These yields were achieved at a reaction temperature of 180 °C and an initial cellulose intake of 0.7 wt % and belong to the upper range for solid catalysts so far presented in the literature.

    The reaction network of the various chemical species involved was investigated and a simple mechanistic approach involving first order reaction kinetics was developed. The concept introduces a one-pot procedure providing a feasible route to green platform chemicals obtained via conversion of coniferous soft wood pulp to levulinic and formic acids, respectively. The model was able to describe the behaviour of the system in a satisfactory manner (degree of explanation 97.8 %). Since the solid catalyst proved to exhibit good mechanical strength under the experimental conditions applied here and a one-pot procedure providing a route to green platform chemicals was developed. A simplified reaction network of the various chemical species involved was investigated and a mechanistic approach involving first order reaction kinetics was developed.

  • 6.
    Ahlquist, Mårten S. G.
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Wang, Ying
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Xue, Liqin
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Sanchez-de-Armas, Rocio
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Proton transfers in first row transition metal complexes2013Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, 1381-INOR- s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 7. Aidas, Kestutis
    et al.
    Olsen, Jogvan Magnus H.
    Kongsted, Jacob
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Photoabsorption of Acridine Yellow and Proflavin Bound to Human Serum Albumin Studied by Means of Quantum Mechanics/Molecular Dynamics2013Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, nr 7, 2069-2080 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Attempting to unravel mechanisms in optical probing of proteins, we have performed pilot calculations of two cationic chromophores-acridine yellow and proflavin-located at different binding sites within human serum albumin, including the two primary drug binding sites as well as a heme binding site. The computational scheme adopted involves classical molecular dynamics simulations of the ligands bound to the protein and subsequent linear response polarizable embedding density functional theory calculations of the excitation energies. A polarizable embedding potential consisting of point charges fitted to reproduce the electrostatic potential and isotropic atomic polarizabilities computed individually for every residue of the protein was used in the linear response calculations. Comparing the calculated aqueous solution-to-protein shifts of maximum absorption energies to available experimental data, we concluded that the cationic proflavin chromophore is likely not to bind albumin at its drug binding site I nor at its heme binding site. Although agreement with experimental data could only be obtained in qualitative terms, our results clearly indicate that the difference in optical response of the two probes is due to deprotonation, and not, as earlier suggested, to different binding sites. The ramifications of this finding for design of molecular probes targeting albumin or other proteins is briefly discussed.

  • 8.
    Aigars, Juris
    Stockholms universitet.
    The role of sediments in the biogeochemical cycles of nutrients in the Gulf of Riga2001Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The sediment biogeochemistry of C, N, P and biologic silica (BSi) plays an important role in cycling of these elements in aquatic ecosystems. In shallow coastal and estuarine systems, water-sediment nutrient dynamics can influence biological processes (e.g., primary production) in overlying waters.

    The objectives of this study are:

    • characterize C, N, P and BSi geochemistry of the surface sediments in the Gulf of Riga,
    • estimate the spatial distribution, including net flux and sink, for organic C, N and P in the Gulf of Riga,
    • examine if there are any appropriate bulk, regional and/or vertical relationships between the nutrients,
    • examine if nutrient biogeochemistry in surface sediments vary as a response to naturally occurring processes i.e., intensity of sedimentation and bioturbation, oxygen deficiency, variation of temperature

    Spatial and vertical distribution reveals that organic C and N ratio is almost independent of sediment characteristics and location, and exhibit a stable value down the sediment core. Over 90 % of carbon and nitrogen in sediments is organic. In contrast, organic P constitutes less than 50 % of the total phosphorus pool. The organic C:N:P ratio in sediments indicate that N and P are decomposed preferentially to C, whereas P is decomposed preferentially to N. The stable C:N ratio in sediments indicates that preferential N decomposition occurs in water column and/or immediately upon settling at sediment surface. Distribution pattern of BSi suggests that accumulation rate of sediments controls BSi concentration. Although nutrient loading from drainage area increased drastically over the past 100 years, vertical profiles of C, N and BSi show no variation in element concentrations except in the top few centimeters. A corresponding increase of benthic biomass most likely results in low elemental accumulation in these sediments.

    Although Gulf of Riga is one of the most productive areas in the Baltic Sea, seasonal alterations of C and N levels were limited. However, during spring and autumn algae blooms total C and N concentrations increased in the study area. Limited data suggests that burrowing amphipods directly impact the C and N concentrations in the top 2-3 cm of sediments. The vertical distribution of P is more dependent on oxygen concentration, which is largely controlled by bioturbation and sedimentation rates. Moreover, the results suggest that bioturbation is largely responsible for temporal accumulation of inorganic P in surface sediments.

    The low unidirectional fluxes of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) in early spring is consistent with low water temperature and poor nutritional quality of experimentally added material. The high water temperature and better nutritional quality of material added in summer, comparatively to winter, resulted in large DIN and DIP fluxes. Moreover, flux experiments under low oxygen conditions and pulse input of large quantities of settling seston suggest that sediment surface might experience lack of oxygen despite availability of oxygen in the overlying water column.

  • 9.
    Akhlaghi, Shahin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Pourrahimi, Amir Masoud
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Hedenqvist, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Sjöstedt, C.
    Bellander, M.
    Gedde, Ulf
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Degradation of carbon-black-filled acrylonitrile butadiene rubber in alternative fuels: Transesterified and hydrotreated vegetable oils2016Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 123, 69-79 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The deterioration of acrylonitrile butadiene rubber (NBR), a common sealing material in automobile fuel systems, when exposed to rapeseed biodiesel and hydrotreated vegetable oil (HVO) was studied. The fuel sorption was hindered in HVO-exposed rubber by the steric constraints of bulky HVO molecules, but it was promoted in biodiesel-exposed rubber by fuel-driven cavitation in the NBR and by the increase in diffusivity of biodiesel after oxidation. The absence of a tan δ peak of the bound rubber and the appearance of carbon black particles devoid of rubber suggested that the cavitation was made possible in biodiesel-aged rubber by the detachment of bound rubber from particle surfaces. The HVO-exposed NBR showed a small decrease in strain-at-break due to the migration of plasticizer from the rubber, and a small increase in the Young’s modulus due to oxidative crosslinking. A drastic decrease in extensibility and Payne-effect amplitude of NBR on exposure to biodiesel was explained as being due to the damage caused by biodiesel to the continuous network of bound rubber-carbon black. A decrease in the ZnO crystal size with increasing exposure time suggested that the particles are gradually dissolved in the acidic components of oxidized biodiesel. The Zn2+ cations released from the dissolution of ZnO particles in biodiesel promoted the hydrolysis of the nitrile groups of NBR.

  • 10.
    Akpe, Victor
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Vernet, Erik
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Madu, Christian
    Obirai, Joseph C.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Understanding the Photochemical Pathway of In Vitro Target Delivery of Aluminium Phthalocyanine: A Mechanistic Approach Using Radical Reaction Chemistry2014Inngår i: ChemPlusChem, ISSN 2192-6506, Vol. 79, nr 5, 671-679 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A classical dye, aluminium phthalocyanine (AlPc), is used to study the photochemical processes involved in the chromophore-assisted laser inactivation technique. Both cell-free and cell-based systems are investigated by novel methods and radical reaction chemistry. Findings on the photochemical pathways in two models representing cell-free and a cell-based systems are reported. In the cell-free system, the unsubstituted, free, fluorescence-active photosensitiser AlPc recovers its fluorescence signal by means of phosphorescence through a reversible photobleaching process. In the cell-based system, photoactivation of substituted AlPc conjugated to an antibody results in the loss of fluorescence signal at the area examined. Reinjection of the AlPc-conjugated antibodies restores the fluorescence signal.

  • 11.
    Alberius, Peter Carl Anders
    et al.
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Dye-loaded particles.2007Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Amorphous particles are provided comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, wherein the amorphous particle comprises from 3% to 20% dye, by wt. of the particle. [on SciFinder(R)]

  • 12. Alberius, Peter Carl Anders
    et al.
    Corkery, Robert W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi (stängd 20110630).
    Spray-drying process for the manufacture of dye-loaded particles.2007Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    According to a first aspect of the invention, a process is provided for the prepn. of amorphous particles comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, the process comprising: (a) providing a precursor of the encapsulating agent in liq. form; (b) providing the one or more dyes in liq. form; (c) mixing the liq. forms; (d) spraying the mixt. to form droplets comprising the one or more dyes and encapsulating agent; and (e) heating the droplets to form the particles comprising the one or more dyes encapsulated by the siliceous encapsulating agent; wherein at least one of the liq. forms provided is aq. and the or each aq. liq. form is acidic. According to a second aspect of the invention, encapsulated dyes made by the process of the first aspect of the invention are provided. [on SciFinder(R)]

  • 13.
    Alberius, Peter Carl Anders
    et al.
    Procter & Gamble Company.
    Corkery, Robert W.
    Procter & Gamble Company.
    Stephens, Alison Fiona.
    Procter & Gamble Company.
    Cosmetic compositions comprising dye-loaded particles.2007Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    According to the invention, a cosmetic compn. is provided comprising: (a) amorphous particles, each amorphous particle comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, wherein the amorphous particle comprises from 3% to 20%, preferably 5% to 15%, more preferably 8% to 12% dye, by wt. of the particle; (b) a cosmetically acceptable carrier. Silica loaded with tartrazine and other dyes are prepd. Cosmetic compns. such as lipsticks and mascaras are prepd. contg. encapsulated dyes, siloxanes and other ingredients. [on SciFinder(R)]

  • 14.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Wood hydrolysates turned valuable2012Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikkel i tidsskrift (Annet vitenskapelig)
  • 15.
    Albán Reyes, Diana Carolina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Eliasson, Bertil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Karlsson, Leif
    AkzoNobel.
    de Wit, Paul
    AkzoNobel.
    Svedberg, Anna
    MoRe Research.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Activation of dissolving celluloses pulp for viscose and cellulose ether production2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Mercerisation of cellulose by alkali treatment is the most common procedure used to activate natural cellulose fibres into many commercial cellulosic materials. During mercerisation, the NaOH solution enters the cellulose fibres, transforming them into a swollen and a highly reactive material called alkali cellulose (Na-Cell). In case NaOH is completely washed out of the cellulose structure, Na-Cell turns into Cellulose II upon drying.

    Traditionally the cellulose is mercerised by suspending it in a 15-20 % NaOH solution. The result is a high (15-25 mol/mol) NaOH: Anhydroglucose  molar ratio (r) and mercerisation in these conditions have been extensively studied. However, in modern production of cellulose ethers, the mercerisation conditions are often very different. The main reason is that any excess of water and OH--ions used during the mercerisation can later react with different chemicals in the process, thus forming unwanted by-products e.g. methanol. One way to avoid this kind of side reaction is by using low-water-content mercerisation conditions, i.e. low (r) = 0.8-1.8 mol/mol and high NaOH concentration (45-55% w/w). The traditional mercerisation is a suspension process while the cellulose during the latter process, i.e low-water-content mercerisation conditions, remains quite “dry”. Thus, although the chemical reaction principles of activation of cellulose for both viscose and cellulose ethers processes are the same, the activation conditions used are often very different. Therefore, the different dependencies of process parameters as well as any similarities between the processes are interesting.

    The presentation summarises the findings presented in two papers which described the influence of the different parameters on the mercerisation/activation of softwood Sulphite dissolving pulp in viscose production conditions (Albán Reyes et al. 2016) and cellulose derivatives production conditions (Albán Reyes et al.) respectively. In the individual studies this has been done by analysing the degree of transformation (DoT) of dissolving pulp to Na-cellulose (or more correctly cellulose II after washing and upon drying) as a function of simultaneous variation of [NaOH], temperature, and reaction time varied using design of experiment. Also the (r) was varied for samples mercerised at dry conditions. A combination of Raman imaging and multivariate data analysis have been used to study the DoT to Cellulose II.

    It was found that the mercerisation under the different conditions was dependent on different parameters. For traditional mercerisation, on the one hand, the temperature was shown to be important for the DoT and showed negative correlation with the data, while [NaOH] showed a positive correlation. On the other hand, at low-water-content mercerisation conditions the (r) was overall most important while the temperature showed no statistical importance in a Partial least squares analysis. Traditional mercerisation gave much higher DoT than the low-water-content mercerisation. Thus,  the data for low-water-content mercerisation was further examined at the different (r). The same chemistry is always expected and the different influences of the parameters seen is understood and discussed in terms of the different physical reaction mechanisms.  

  • 16.
    Albán Reyes, Diana Carolina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Eriksson, Bertil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Karlsson, Leif
    AkzoNobel.
    de Wit, Paul
    AkzoNobel.
    Svdberg, Anna
    MoRe Research.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Activation of dissolving celluloses pulp for viscose and cellulose ether production2016Inngår i: The 7th workshop on Cellulose, Regenerated cellulose and cellulose derivatives, 2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Mercerisation of cellulose by alkali treatment is the most common procedure used to activate natural cellulose fibres into many commercial cellulosic materials. During mercerisation, the NaOH solution enters the cellulose fibres, transforming them into a swollen and a highly reactive material called alkali cellulose (Na-Cell). In case NaOH is completely washed out of the cellulose structure, Na-Cell turns into Cellulose II upon drying.

    Traditionally the cellulose is mercerised by suspending it in a 15-20 % NaOH solution. The result is a high (15-25 mol/mol) NaOH: Anhydroglucose  molar ratio (r) and mercerisation in these conditions have been extensively studied. However, in modern production of cellulose ethers, the mercerisation conditions are often very different. The main reason is that any excess of water and OH--ions used during the mercerisation can later react with different chemicals in the process, thus forming unwanted by-products e.g. methanol. One way to avoid this kind of side reaction is by using low-water-content mercerisation conditions, i.e. low (r) = 0.8-1.8 mol/mol and high NaOH concentration (45-55% w/w). The traditional mercerisation is a suspension process while the cellulose during the latter process, i.e low-water-content mercerisation conditions, remains quite “dry”. Thus, although the chemical reaction principles of activation of cellulose for both viscose and cellulose ethers processes are the same, the activation conditions used are often very different. Therefore, the different dependencies of process parameters as well as any similarities between the processes are interesting.

    The presentation summarises the findings presented in two papers which described the influence of the different parameters on the mercerisation/activation of softwood Sulphite dissolving pulp in viscose production conditions (Albán Reyes et al. 2016) and cellulose derivatives production conditions (Albán Reyes et al.) respectively. In the individual studies this has been done by analysing the degree of transformation (DoT) of dissolving pulp to Na-cellulose (or more correctly cellulose II after washing and upon drying) as a function of simultaneous variation of [NaOH], temperature, and reaction time varied using design of experiment. Also the (r) was varied for samples mercerised at dry conditions. A combination of Raman imaging and multivariate data analysis have been used to study the DoT to Cellulose II.

    It was found that the mercerisation under the different conditions was dependent on different parameters. For traditional mercerisation, on the one hand, the temperature was shown to be important for the DoT and showed negative correlation with the data, while [NaOH] showed a positive correlation. On the other hand, at low-water-content mercerisation conditions the (r) was overall most important while the temperature showed no statistical importance in a Partial least squares analysis. Traditional mercerisation gave much higher DoT than the low-water-content mercerisation. Thus,  the data for low-water-content mercerisation was further examined at the different (r). The same chemistry is always expected and the different influences of the parameters seen is understood and discussed in terms of the different physical reaction mechanisms.  

  • 17.
    Albán Reyes, Diana Carolina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Schröder, Ulf
    AkzoNobel.
    Karlsson, Leif
    AkzoNobel.
    de Wit, Paul
    AkzoNobel.
    Eliasson, Bertil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Activation of dissolving cellulose pulp at low water content2015Inngår i: 4th EPNOE International Polysaccharide Conference: Polysaccharides and polysaccharide-based advance materials: from science to industry, 2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Mercerisation of cellulose by alkali treatment is the first step in modifying natural cellulose fibres into many commercial cellulosic materials. During treatment, the fiber transforms into a reactive and highly swollen material called alkali cellulose (Na-Cell). In case NaOH is washed out of the cellulose structure, Na-Cell turn into Cellulose II upon drying (Langan et al. 2001).

     

    The aim of the present study was to gain a better understanding of the mercerisation of dissolving cellulose pulp at low water content. This has been done by spraying NaOH onto milled cellulose in a kneader, then washing the cellulose to neutrality to stop the reaction. After drying the transformation degree to cellulose II was analysed. The experiments include variation of temperature (30-60°C), reaction time (5 and 25 min), [NaOH] (45-55%), and NaOH:Cellulose molar ratio (0.8- 1.8). A combination of NIR Raman imaging and multivariate data analysis have been used to study the transformation degree.

     

    To the authors’ knowledge, this is the first time the influence of NaOH: Cellulose molar ratio on the mercerisation process has been studied in a single model together with temperature, reaction time and [NaOH]. Our results indicate that increased NaOH: Cellulose molar ratio has a significant positive influence on transformation degree of dissolving cellulose pulp at low water content.

  • 18. Aldongarov, Anuar
    et al.
    Irgibaeva, Irina
    Hermansson, Kersti
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Theoretical study on passivation of small CdS clusters2014Inngår i: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 112, nr 5-6, 674-682 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We use density functional theory quantum chemical calculations to model optical properties of small cadmium sulphide clusters in order to explore the formation of trap states and the possibility to achieve surface passivation. The addition of capping oxygen ions on the surface of the CdS quantum dots is found to passivate the single-bonded Cd atoms. Added Cu ions resulted in the formation of deep trap states for certain locations of the copper impurity, while removal of single-bonded Cd atoms by adding S or SH groups leads to a band gap increase.

  • 19. Alexander, Jan
    et al.
    Benford, Diane
    Boobis, Alan
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för miljökemi.
    Scientific Opinion on Hexabromocyclododecanes (HBCDDs) in Food2011Inngår i: EFSA Journal, ISSN 1831-4732, Vol. 9, nr 7, 2296- s.Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    EFSA was asked by the European Commission to deliver a scientific opinion on hexabromocyclododecanes (HBCDDs) in food. HBCDDs are additive flame retardants primarily used in expanded and extruded polystyrene applied as construction and packing materials, and in textiles. Technical HBCDD predominantly consists of three stereoisomers (α-, β- and γ-HBCDD). Also δ- and ε-HBCDD may be present but at very low concentrations. HBCDDs are present in the environment and likewise in biota and in food and feed. Data from the analysis of HBCDDs in 1,914 food samples were provided to EFSA by seven European countries, covering the period from 2000 to 2010. The Panel on Contaminants in the Food Chain (CONTAM Panel) selected α-, β- and γ-HBCDD to be of primary interest. Since all toxicity studies were carried out with technical HBCDD, a risk assessment of individual stereoisomers was not possible. Main targets were the liver, thyroid hormone homeostasis and the reproductive, nervous and immune systems. HBCDDs are not genotoxic. The CONTAM Panel identified neurodevelopmental effects on behaviour as the critical endpoint, and derived a benchmark dose lower confidence limit for a benchmark response of 10 % (BMDL10) of 0.79 mg/kg body weight. Due to the limitations and uncertainties in the current data base, the CONTAM Panel concluded that it was inappropriate to use this BMDL to establish a health based guidance value, and instead used a margin of exposure (MOE) approach for the health risk assessment of HBCDDs. Since elimination characteristics of HBCDDs in animals and humans differ, the Panel used the body burden as starting point for the MOE approach. The CONTAM Panel concluded that current dietary exposure to HBCDDs in the European Union does not raise a health concern. Also additional exposure, particularly of young children, to HBCDDs from house dust is unlikely to raise a health concern

  • 20. Alexander, Jan
    et al.
    Benford, Diane
    Boobis, Alan
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för miljökemi.
    Scientific Opinion on Polybrominated Diphenyl Ethers (PBDEs) in Food2011Inngår i: EFSA Journal, ISSN 1831-4732, Vol. 9, nr 5, 2156- s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 21. Alexander, Jan
    et al.
    Benford, Diane
    Boobis, Alan
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för miljökemi.
    Scientific Opinion on Tetrabromobisphenol A (TBBPA) and its derivatives in food: EFSA Panel on Contaminants in the Food Chain (CONTAM)2011Inngår i: EFSA Journal, ISSN 1831-4732, Vol. 9, nr 12, 2477- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    EFSA was asked by the European Commission to deliver a scientific opinion on tetrabromobisphenol A (TBBPA) and its derivatives in food. TBBPA and its derivatives are widely used as flame retardants. TBBPA is primarily used as reactive flame retardant covalently bound to epoxy and polycarbonate resins. TBBPA derivatives are used as either reactive or additive intermediates in polymer manufacture. Data from the analysis of TBBPA in 344 food samples were submitted to EFSA by two European countries (Norway and Spain), covering the period from 2007 to 2010. All samples were in the food group “Fish and other seafood”, and all analytical results were reported as less than the limit of quantification (LOQ) (about 1 ng/g wet weight). Toxicological studies with TBBPA have been carried out using different experimental designs with single or repeated administration during gestation, postnatally or in adulthood. The main target is thyroid hormone homeostasis. TBBPA is not genotoxic. There are no indications that TBBPA might be carcinogenic. The Panel on Contaminants in the Food Chain (CONTAM Panel) identified a lower confidence limit for a benchmark response of 10 % (BMDL10) of 16 mg/kg b.w. reported for changes in thyroid hormones as the critical reference point. Due to the limitations and uncertainties in the database, the CONTAM Panel concluded that it was inappropriate to use this BMDL to establish a health based guidance value, and therefore used a margin of exposure (MOE) approach for the health risk assessment of TBBPA. In view of the large MOEs, the CONTAM Panel concluded that current dietary exposure to TBBPA in the European Union does not raise a health concern. Also exposure of infants via human milk does not raise a health concern. Additional exposure, particularly of young children, to TBBPA from house dust is unlikely to raise a health concern.

  • 22.
    Alriksson, Björn
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Ethanol from lignocellulose: Alkali detoxification of dilute-acid spruce hydrolysates2006Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Detoxification of dilute-acid lignocellulose hydrolysates by treatment with Ca(OH)2 (overliming) efficiently improves the production of fuel ethanol, but is associated with drawbacks like sugar degradation and CaSO4 precipitation. In factorial designed experiments, in which pH and temperature were varied, dilute-acid spruce hydrolysates were treated with Ca(OH)2, NH4OH or NaOH. The concentrations of sugars and inhibitory compounds were measured before and after the treatments. The fermentability was examined using the yeast Saccharomyces cerevisiae and compared with reference fermentations of synthetic medium without inhibitors. The treatment conditions were evaluated by comparing the balanced ethanol yield, which takes both the degradation of sugars and the ethanol production into account. Treatment conditions resulting in excellent fermentability and minimal sugar degradation were possible to find regardless of whether Ca(OH)2, NH4OH or NaOH was used. Balanced ethanol yields higher than those of the reference fermentations were achieved for hydrolysates treated with all three types of alkali. As expected, treatment with Ca(OH)2 gave rise to precipitated CaSO4. The NH4OH treatments gave rise to a brownish precipitate but the amounts of precipitate formed were relatively small. No precipitate was observed in treatments with NaOH. The possibility that the ammonium ions from the NH4OH treatments gave a positive effect as an extra source of nitrogen during the fermentations was excluded after experiments in which NH4Cl was added to the medium. The findings presented can be used to improve the effectiveness of alkali detoxification of lignocellulose hydrolysates and to minimize problems with sugar degradation and formation of precipitates.

  • 23.
    Alriksson, Björn
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Ethanol from lignocellulose: Management of by-products of hydrolysis2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Fuel ethanol can be produced from lignocellulosic materials, such as residues from agriculture and forestry. The polysaccharides of lignocellulose are converted to sugars by hydrolysis and the sugars can then be fermented to ethanol using microorganisms. However, during hydrolysis a wide range of by-products are also generated. By-product formation can affect ethanol yield and productivity. Management of by-products of hydrolysis is therefore important in the development of commercially viable production of cellulosic ethanol.

    Detoxification of inhibitory dilute-acid lignocellulose hydrolysates by treatment with Ca(OH)2 (overliming) efficiently improves the fermentability, but is associated with drawbacks like sugar degradation and CaSO4 precipitation. In factorial designed experiments, in which pH and temperature were varied, dilute-acid spruce hydrolysates were treated with Ca(OH)2, NH4OH or NaOH. The concentrations of sugars and inhibitory compounds were measured before and after the treatments. The fermentability was examined using the yeast Saccharomyces cerevisiae and compared with reference fermentations of synthetic medium without inhibitors. The treatment conditions were evaluated by comparing the balanced ethanol yield, which takes both the degradation of sugars and the ethanol production into account. Treatment conditions resulting in excellent fermentability and minimal sugar degradation were possible to find regardless of whether Ca(OH)2, NH4OH or NaOH was used. Balanced ethanol yields higher than those of the reference fermentations were achieved for hydrolysates treated with all three types of alkali. As expected, treatment with Ca(OH)2 gave rise to precipitated CaSO4. The NH4OH treatments gave rise to a brownish precipitate but the amounts of precipitate formed were relatively small. No precipitate was observed in treatments with NaOH. The findings presented can be used to improve the effectiveness of alkali detoxification of lignocellulose hydrolysates and to minimize problems with sugar degradation and formation of precipitates.

    Overexpression of different S. cerevisiae genes was investigated with the aim to engineer a biocatalyst with increased inhibitor tolerance. Overexpression of YAP1, a gene encoding a transcription factor, conveyed increased resistance to lignocellulose-derived inhibitors as well as to a dilute-acid hydrolysate of spruce.

    Recombinant Aspergillus niger expressing the Hypocrea jecorina endoglucanase Cel7B was cultivated on spent lignocellulose hydrolysate (stillage). The fungus simultaneously removed inhibitors present in the stillage and produced higher amounts of endoglucanase than when it was grown in a standard medium with comparable monosaccharide content. The concept can be applied for on-site production of enzymes in a cellulose-to-ethanol process and facilitate recycling of the stillage stream.

  • 24. Alriksson, Björn
    et al.
    Eskilsson, Martin
    Johansson, Emma
    Lapidot, Shaul
    Norström,, Markus
    Schultz-Eklund, Ola
    Shkedi, Yoram
    Svedberg, Anna
    Svensson, Stefan
    Swerin, Agne
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Europe’s first pilot facility for cellulose nanocrystals (CNC)2016Inngår i: Annual Surface and Materials Chemistry Symposium and Materials for tomorrow, ASMCS 2016, November 8-10, 2016, Gothenburg, Sweden, 2016Konferansepaper (Fagfellevurdert)
  • 25.
    Alriksson, Björn
    et al.
    Karlstads universitet, Institutionen för kemi.
    Horváth, Ilona Sárvári
    Karlstads universitet, Institutionen för kemi.
    Sjöde, Anders
    Karlstads universitet, Institutionen för kemi.
    Nilvebrant, Nils-Olof
    Karlstads universitet, Institutionen för kemi.
    Jönsson, Leif J
    Karlstads universitet, Institutionen för kemi.
    Ammonium hydroxide detoxification of spruce acid hydrolysates.2005Inngår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1599-0291, Vol. 121-124, 911-22 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When dilute-acid hydrolysates from spruce are fermented to produce ethanol, detoxification is required to make the hydrolysates fermentable at reasonable rates. Treatment with alkali, usually by overliming, is one of the most efficient approaches. Several nutrients, such as ammonium and phosphate, are added to the hydrolysates prior to fermentation. We investigated the use of NH4OH for simultaneous detoxification and addition of nitrogen source. Treatment with NH4OH compared favorably with Ca(OH)2, Mg(OH)2, Ba(OH)2, and NaOH to improve fermentability using Saccharomyces cerevisiae. Analysis of monosaccharides, furan aldehydes, phenols, and aliphatic acids was performed after the different treatments. The NH4OH treatments, performed at pH 10.0, resulted in a substantial decrease in the concentrations of furfural and hydroxymethylfurfural. Under the conditions studied, NH4OH treatments gave better results than Ca(OH)2 treatments. The addition of an extra nitrogen source in the form of NH4Cl at pH 5.5 did not result in any improvement in fermentability that was comparable to NH4OH treatments at alkaline conditions. The addition of CaCl2 or NH4Cl at pH 5.5 after treatment with NH4OH or Ca(OH)2 resulted in poorer fermentability, and the negative effects were attributed to salt stress. The results strongly suggest that the highly positive effects of NH4OH treatments are owing to chemical conversions rather than stimulation of the yeast cells by ammonium ions during the fermentation.

  • 26.
    Alriksson, Björn
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Rose, Shaunita, H
    Department of Microbiology, University of Stellenbosch, South Africa.
    van Zyl, Wilhelm, H
    Department of Microbiology, University of Stellenbosch, South Africa.
    Sjöde, Anders
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Nilvebrant, Nils-Olof
    STFI-Packforsk AB, Stockholm, Sweden.
    Jönsson, Leif J.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Cellulase Production from Spent Lignocellulose Hydrolysates with Recombinant Aspergillus niger.2009Inngår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 75, nr 8, 2366-2374 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 27.
    Amadei, Damien
    et al.
    Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, UMR 5248, F-33600 Pessac, France..
    Chatzidaki, Maria D.
    Örebro universitet, Institutionen för naturvetenskap och teknik. Natl Hellen Res Fdn, Inst Theoret & Phys Chem, Inst Biol Med Chem & Biotechnol, GR-11635 Athens, Greece.
    Devienne, Julia
    Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, UMR 5248, F-33600 Pessac, France..
    Monteil, Julien
    Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, UMR 5248, F-33600 Pessac, France..
    Cansell, Maud
    Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, UMR 5248, F-33600 Pessac, France..
    Xenakis, Aristotelis
    Natl Hellen Res Fdn, Inst Theoret & Phys Chem, Inst Biol Med Chem & Biotechnol, GR-11635 Athens, Greece.;Univ Orebro, MTM Res Ctr, Sch Sci & Technol, S-31705 Orebro, Sweden..
    Leal-Calderon, Fernando
    Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, UMR 5248, F-33600 Pessac, France..
    Low shear-rate process to obtain transparent W/O fine emulsions as functional foods2014Inngår i: Food Research International, ISSN 0963-9969, E-ISSN 1873-7145, Vol. 62, 533-540 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Edible transparent emulsions of the water-in-oil (W/O) type are highly sought after and currently not available. In such materials, the water droplets can be advantageously used as reservoirs to encapsulate biologically active hydrophilic substances (minerals, antioxidants, etc.). The emulsions must remain transparent, fluid and kinetically stable to meet consumers' requirements. In this paper, we describe a simple yet versatile process to fabricate food grade transparent W/O emulsions. Our method involves the preparation of coarse emulsions which are submitted to shear under laminar flow conditions to reduce their average droplet size. The process generates negligible heat and consequently, it preserves the integrity of thermally sensitive compounds. The obtained emulsions contain between 5 and 10 wt.% of aqueous droplets whose average droplet size is lower than 200 nm. They are kinetically stable for at least 2 months. Transparency results from the relatively low droplet size and the incorporation in the aqueous phase of hydrophilic solutes that decrease the refractive index mismatch between the two immiscible phases.

  • 28.
    An, Junxue
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Dédinaité, Andra
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Nilsson, Anki
    Holgersson, Jan
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Comparison of a Brush-with-Anchor and a Train-of-Brushes Mucin on Poly(methyl methacrylate) Surfaces: Adsorption, Surface Forces, and Friction2014Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, nr 4, 1515-1525 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interfacial properties of two types of mucins have been investigated at the aqueous solution/poly(methyl methacrylate) (PMMA) interface. One is commercially available bovine submaxillary mucin, BSM, which consists of alternating glycosylated and nonglycosylated regions. The other one is a recombinant mucin-type fusion protein, PSGL-1/mIgG(2b), consisting of a glycosylated mucin part fused to the Fc part of an immunoglobulin. PSGL-1/mIgG(2b) is mainly expressed as a (timer upon production. A quartz crystal microbalance with dissipation was used to study the adsorption of the mucins to PMMA surfaces. The mass of the adsorbed mucin layers, including the adsorbed mucin and water trapped in the layer, was found to be significantly higher for PSGL-1/mIgG(2b) than for BSM. Atomic force microscopy with colloidal probe was employed to study interactions and frictional forces between mucin-coated PMMA surfaces. Purely repulsive forces of steric origin were Observed between PSGL-1/mIgG(2b) mucin layers, whereas a small adhesion was detected between BSM layers and attributed to bridging. Both mucin layers reduced the friction force between PMMA surfaces in aqueous solution. The reduction was, however, significantly more pronounced for PSGL-1/mIgG(2b). The effective friction coefficient between PSGL-1/mIgG(2b)-coated PMMA surfaces is as low as 0.02 at low loads, increasing to 0.24 at the highest load explored, 50 nN. In contrast, a friction coefficient of around 0.7 was obtained between BSM-coated PMMA surfaces. The large differences in interfacial properties for the two mucins are discussed in relation to their structural differences.

  • 29.
    An, Junxue
    et al.
    KTH Royal Institute of Technology,Stockholm, Sweden.
    Liu, Xiaoyan
    KTH Royal Institute of Technology,Stockholm, Sweden.
    Dedinaite, Andra
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor. KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science.
    Korchagina, Evgeniya
    University of Montreal, Montreal, Canada .
    Winnik, Francoise M.
    University of Montreal, Montreal, Canada ; WPI International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Tsukuba, Ibaraki, Japan ; University of Helsinki, Helsinki, Finland.
    Claesson, Per M.
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor. KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science.
    Dedinaite, Andra
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor. KTH Royal Institute of Technology,Stockholm, Sweden.
    Effect of solvent quality and chain density on normal and frictional forces between electrostatically anchored thermoresponsive diblock copolymer layers2017Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 487, 88-96 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Equilibration in adsorbing polymer systems can be very slow, leading to different physical properties at a given condition depending on the pathway that was used to reach this state. Here we explore this phenomenon using a diblock copolymer consisting of a cationic anchor block and a thermoresponsive block of poly(2-isopropyl-2-oxazoline), PIPOZ. We find that at a given temperature different polymer chain densities at the silica surface are achieved depending on the previous temperature history. We explore how this affects surface and friction forces between such layers using the atomic force microscope colloidal probe technique. The surface forces are purely repulsive at temperatures <40 °C. A local force minimum at short separation develops at 40 °C and a strong attraction due to capillary condensation of a polymer-rich phase is observed close to the bulk phase separation temperature. The friction forces decrease in the cooling stage due to rehydration of the PIPOZ chain. A consequence of the adsorption hysteresis is that the friction forces measured at 25 °C are significantly lower after exposure to a temperature of 40 °C than prior to heating, which is due to higher polymer chain density on the surface after heating.

  • 30.
    An, Wei
    et al.
    Brookhaven National Laboratory, USA.
    Baber, Ashleigh E.
    Brookhaven National Laboratory, USA.
    Xu, Fang
    Stony Brook University, USA.
    Soldemo, Markus
    KTH.
    Weissenrieder, Jonas
    KTH.
    Stacchiola, Dario
    Brookhaven National Laboratory, USA.
    Liu, Ping
    Brookhaven National Laboratory, USA.
    Mechanistic Study of CO Titration on CuxO/Cu(111) (x <= 2) Surfaces2014Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, nr 8, 2364-2372 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reducibility of metal oxides is of great importance to their catalytic behavior. Herein, we combined ambient-pressure scanning tunneling microscopy (AP-STM), X-ray photoemission spectroscopy (AP-XPS), and DFT calculations to study the CO titration of CuxO thin films supported on Cu(111) (CuxO/Cu(111)) aiming to gain a better understanding of the roles that the Cu(111) support and surface defects play in tuning catalytic performances. Different conformations have been observed during the reduction, namely, the 44 structure and a recently identified (5-7-7-5) Stone-Wales defects (5-7 structure). The DFT calculations revealed that the Cu(111) support is important to the reducibility of supported CuxO thin films. Compared with the case for the Cu2O(111) bulk surface, at the initial stage CO titration is less favorable on both the 44 and 5-7 structures. The strong CuxO <-> Cu interaction accompanied with the charge transfer from Cu to CuxO is able to stabilize the oxide film and hinder the removal of O. However, with the formation of more oxygen vacancies, the binding between CuxO and Cu(111) is weakened and the oxide film is destabilized, and Cu2O(111) is likely to become the most stable system under the reaction conditions. In addition, the surface defects also play an essential role. With the proceeding of the CO titration reaction, the 5-7 structure displays the highest activity among all three systems. Stone-Wales defects on the surface of the 5-7 structure exhibit a large difference from the 44 structure and Cu2O(111) in CO binding energy, stability of lattice oxygen, and, therefore, the reduction activity. The DFT results agree well with the experimental measurements, demonstrating that by adopting the unique conformation, the 5-7 structure is the active phase of CuxO, which is able to facilitate the redox reaction and the Cu2O/Cu(111)<-> Cu transition.

  • 31. An, Wei
    et al.
    Baber, Ashleigh E.
    Xu, Fang
    Soldemo, Markus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Weissenrieder, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Stacchiola, Dario
    Liu, Ping
    Mechanistic Study of CO Titration on CuxO/Cu(111) (x <= 2) Surfaces2014Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, nr 8, 2364-2372 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reducibility of metal oxides is of great importance to their catalytic behavior. Herein, we combined ambient-pressure scanning tunneling microscopy (AP-STM), X-ray photoemission spectroscopy (AP-XPS), and DFT calculations to study the CO titration of CuxO thin films supported on Cu(111) (CuxO/Cu(111)) aiming to gain a better understanding of the roles that the Cu(111) support and surface defects play in tuning catalytic performances. Different conformations have been observed during the reduction, namely, the 44 structure and a recently identified (5-7-7-5) Stone-Wales defects (5-7 structure). The DFT calculations revealed that the Cu(111) support is important to the reducibility of supported CuxO thin films. Compared with the case for the Cu2O(111) bulk surface, at the initial stage CO titration is less favorable on both the 44 and 5-7 structures. The strong CuxO <-> Cu interaction accompanied with the charge transfer from Cu to CuxO is able to stabilize the oxide film and hinder the removal of O. However, with the formation of more oxygen vacancies, the binding between CuxO and Cu(111) is weakened and the oxide film is destabilized, and Cu2O(111) is likely to become the most stable system under the reaction conditions. In addition, the surface defects also play an essential role. With the proceeding of the CO titration reaction, the 5-7 structure displays the highest activity among all three systems. Stone-Wales defects on the surface of the 5-7 structure exhibit a large difference from the 44 structure and Cu2O(111) in CO binding energy, stability of lattice oxygen, and, therefore, the reduction activity. The DFT results agree well with the experimental measurements, demonstrating that by adopting the unique conformation, the 5-7 structure is the active phase of CuxO, which is able to facilitate the redox reaction and the Cu2O/Cu(111)<-> Cu transition.

  • 32. Anderbrant, Olle
    et al.
    Lyons, D. Barry
    Bång, Joakim
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Sex Pheromone of the Introduced Pine Sawfly, Diprion similis (Diprionidae), Revisited: No Activity of Earlier Reported SynergistsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Extracts of Diprion similis females were found to contain about 15 ng of the sex pheromone precursor 3,7-dimethylpentadecan-2-ol per female. When analysing the extracts after derivatisation with (2S)-2-acetoxypropionyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)-3,7-dimethylpentadecan-2-ol. Also other stereoisomers of 3,7-dimethylpentadecan-2-ol were identified in the extract namely, 1% of (2R,3S,7S) , 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed an identical spectrum to 3,7-dimethylpentadecan-2-ol, both in SIM and full scan mode. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)-3,7-dimethylpentadecan-2-ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. In none of the tests were any synergistic effects detected and the threo four-isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo-blend without losing efficiency.

  • 33.
    Anderson, Fredrik
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Rheological changes at the air-liquid interface and examining different kind of magnetic needles2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The main objective in this work was to learn how the instrument, the Interfacial Shear

    Rheometer (ISR400), worked and to investigate how the rheological properties, storage

    modulus (elasticity), G' and loss modulus (viscous), G'', changes when the surface

    pressure at the air-liquid interphase changes. The second objective were to examine the

    different kind of magnetic needles used in the experiments and to conclude which type of

    needle is best for its specific field of analysis.

    It was concluded that the relative heavy needle with mass 70.6 mg and length 50 mm

    was best for systems where the viscous and elastic components are significantly large,

    where the inertia of the needle is not dominant. It also worked of using the heavier needle

    for a system of phospholipids.

    For the hydroxystearic acid (HSA) experiment that were tested on NaCl sub-phase there

    was a clear improvement after switching from the heavy needle (mass 41.5 mg; length 51

    mm) to the relative lighter needle (mass 6.94 mg; length 34.7 mm). The values for the

    dynamic modulus therefore had a better agreement with reference literature.

    A spread layer of class II hydrophobins (HFBII) could be compressed to a surface

    pressure of 46 mNm-1. The G' and G'' values from the frequency sweep were discarded

    because the monolayer turned into a very viscous-like liquid, and the oscillating needle,

    after compression, was kind of stuck in the sub-phase and moved very staggering during

    a frequency sweep.

    The needle comparison experiment with silica particles 10 wt% Bindzil CC30 (BCC30),

    at pH 3.5 was done to see if there was any difference in the sensitivity for the needles at

    the interface which consisted of a pure 10 mM NaCl solution or a 10 mM NaCl solution

    with BCC30 added to it. The differences were negligible in terms of surface tension but

    there was a clear difference between the heavy needle and the light needle, when

    oscillating at higher frequencies (>≈6 rad/s).

    With this study, the understanding of ISR400 has increased largely. Several issues have

    been addressed and the results provide a good basis for further studies within the many

    areas the instrument can be used for. Despite the project's time limit, and the fact that the

    instrument was new and untested where the project was carried out, focus areas were

    prioritized so good results could be achieved within reasonable goals.

  • 34.
    Andersson, Håkan S.
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för kemi och biomedicin (KOB).
    Jacobsson, Erik
    Uppsala University.
    Eriksson, Camilla
    Uppsala University.
    Hedström, Martin
    Lund University.
    Seth, Henrik
    Gothenburg University.
    McEvoy, Eric G
    Sundberg, Per
    Gothenburg University.
    Strand, Malin
    Swedish agricultural university (SLU).
    Göransson, Ulf
    Uppsala University.
    Discovery of peptide toxins in ribbon worms: challenging claims of tetrodotoxin production2015Konferansepaper (Annet vitenskapelig)
  • 35.
    Andersson, Håkan S.
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för kemi och biomedicin (KOB).
    Jacobsson, Erik
    Uppsala University.
    Eriksson, Camilla
    Uppsala University.
    Rosengren, K. Johan
    University of Queensland.
    Andrén, Per
    Uppsala University.
    Strand, Malin
    Swedish agricultural university (SLU).
    Göransson, Ulf
    Uppsala University.
    Discovery of peptide toxins in the bootlace worm, the world's longest animal2015Konferansepaper (Annet vitenskapelig)
  • 36.
    Andersson, Nina
    et al.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Corkery, Robert W.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Alberius, Peter C. A.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    One-pot synthesis of well ordered mesoporous magnetic carriers2007Inngår i: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 17, nr 26, 2700-2705 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The facile preparation of a mesoporous magnetic carrier technology is demonstrated. The micron-sized spherical mesostructured particles are prepared using a newly-developed, one-step, combined emulsion and solvent evaporation (ESE) method. The surfactant-templated silica matrix display a well-ordered internal pore architecture. Very limited pore blocking, and only to a limited degree disordered- or worm-like structures are observed, induced by the iron oxide nanoparticles added to provide the superparamagnetic properties.The iron oxide content was precisely controlled, and themagnetic properties were well preserved during the process. Finally we demonstrate the applicability of the magnetically separable mesoporous material as an adsorbent for specific dissolved materials from dilute aqueous solutions.

  • 37.
    Andersson, Nina
    et al.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Kronberg, Bengt
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Corkery, Robert W.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Alberius, Peter
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Combined Emulsion and Solvent Evaporation (ESE) Synthesis Route to Well-Ordered Mesoporous Materials2007Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, nr 3, 1459-1464 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Control over morphol. and internal mesostructure of surfactant templated silicas remains a challenge, esp. when considering scaling lab. syntheses up to industrial vols. Here we report a method combining emulsification with the evapn.-induced self-assembly (EISA) method for prepg. spherical, mesoporous silica particles. This emulsion and solvent evapn. (ESE) method has several potential advantages over classic pptn. routes: it is easily scaled while providing superior control over stoichiometric homogeneity of templating surfactants and inorg. precursors, and particle sizes and distributions are detd. by principles developed for manipulating droplet sizes within water-in-oil emulsions. To demonstrate the method, triblock copolymer P104 is used as a templating amphiphile, generating unusually well-ordered 2D hexagonal (P6mm) mesoporous silica, while particle sizes and morphologies were controlled by varying the type of emulsifier and the method for emulsification. [on SciFinder(R)]

  • 38.
    Andrén, Daniel
    et al.
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Shao, Lei
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Länk, Nils Odebo
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Acimovic, Srdjan S.
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Johansson, Peter
    Örebro universitet, Institutionen för naturvetenskap och teknik. Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Käll, Mikael
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Probing Photothermal Effects on Optically Trapped Gold Nanorods by Simultaneous Plasmon Spectroscopy and Brownian Dynamics Analysis2017Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, nr 10, 10053-10061 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plasmonic gold nanorods are prime candidates for a variety of biomedical, spectroscopy, data storage, and sensing applications. It was recently shown that gold nanorods optically trapped by a focused circularly polarized laser beam can function as extremely efficient nanoscopic rotary motors. The system holds promise for-applications ranging from nanofluidic flow control and nanorobotics to biomolecular actuation and analysis. However, to fully exploit this potential, one needs to be able to control and understand heating effects associated with laser trapping. We investigated photothermal heating of individual rotating gold nanorods by simultaneously probing their localized surface plasmon resonance spectrum and rotational Brownian dynamics over extended periods of time. The data reveal an extremely slow nanoparticle reshaping process, involving migration of the order of a few hundred atoms per minute, for moderate laser powers and a trapping wavelength close to plasmon resonance. The plasmon spectroscopy and Brownian analysis allows for separate temperature estimates based on the refractive index and the viscosity of the water surrounding a trapped nanorod. We show that both measurements yield similar effective temperatures, which correspond to the actual temperature at a distance of the order 10-15 nm from the particle surface. Our results shed light on photothermal processes on the nanoscale and will be useful in evaluating the applicability and performance of nanorod motors and optically heated nanoparticles for a variety of applications.

  • 39.
    Ankerfors, Caroline
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Johansson, Erik
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Pettersson, Torbjörn
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Use of polyelectrolyte complexes and multilayers from polymers and nanoparticles to create sacrificial bonds between surfaces2013Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 391, 28-35 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, particle polyelectrolyte complexes (PPECs) were formed by mixing cationic polyacrylamide (CPAM) and silica nanoparticles using the jet mixing technique. Within certain limits, the size of the formed PPECs could be controlled. The aim was to prepare PPECs with embedded sacrificial bonds, similar to those found in bones. Examination of PPEC adsorption to silica model surfaces indicated that,smaller PPECs adsorbed to a higher level than larger ones, due to the higher diffusion speed of smaller complexes. Adsorption studies of the same components as in the PPECs, but arranged in multilayers, that is, particle polyelectrolyte multilayers (PPEMs), indicated a stable, gradual build-up of material on the surface with smaller nanoparticles, whereas PPEMs comprising elongated nanoparticles appeared to be more loosely adsorbed onto the surface when the nanoparticles were in the outer layer, due to repulsive forces within the adsorbed layer. The AFM colloidal probe technique was used to study the interaction between surfaces treated with PPECs, multilayers, or polyelectrolyte complexes (PECs). The results showed that the expected long-range disentanglement could be achieved with PPECs but that the pull-off forces were generally low. Treatment with PPEMs comprising the same polymer and nanoparticle components produced higher pull-off values, together with disentanglement behaviour, possibly due to better contact between the surfaces. Adhesion experiments with polymer PECs showed significantly higher pull-off values than with the PPECs, probably due to polymer interdiffusion across the surface boundary.

  • 40. Annergren, Göran
    et al.
    Kvarnlöf, Niklas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sulfitmassa: Översikt kring Processfrågor, Marknad och Framtid2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Karlstads universitet har tagit på sig uppgiften att försöka sammanställa det kunnande som idag finns inom landet kring sulfitmassa och sulfitprocesser. Eftersom antalet massabruk som tillverkar sulfitmassa sakta sjunker är detta en viktig uppgift för att i någon mån kunna behålla det stora kunnande som en gång fanns kring denna process.

    Denna rapport belyser bl.a. viktiga processfrågor kring framställningen av pappers- och dissolvingmassor från sulfitprocessen.

  • 41.
    Anoshkin, Ilya
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Nefedova, Irina
    Dmitri, Lioubtchenko
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Nefedov, Igor
    Räisänen, Antti
    Single walled carbon nanotube quantification method employing the Raman signal intensity2017Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 116, 547-552 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new technique for measuring the number of single walled carbon nanotubes (SWCNTs) and their concentration in a carbon nanotube layer is developed in this work. It is based on the G peak intensity of the Raman spectrum, together with precise mass and optical absorbance measurements. The dependence of the number of the carbon nanotubes on the phonon scattering intensity is observed. This method opens an opportunity for the quantitative mapping of sp2 carbon atom distribution in the SWCNT layers with a resolution limited by the focused laser spot size.

  • 42.
    Ansari, Farhan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Galland, Sylvain
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Johansson, Mats K. G.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Skrivfars, Mikael
    Plummer, Christopher
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Biocomposites of nanofibrillated cellulose with thermoset resins2014Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, 41-CELL- s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 43. Ao, Xianyu
    et al.
    Wang, Xuyue
    Yin, Guanbo
    Dang, Kangkang
    Xue, Yali
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. Zhejiang University, China.
    Broadband Metallic Absorber on a Non-Planar Substrate2015Inngår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 11, nr 13, 1526-1530 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Absorbers for visible and near-infrared light are realized by depositing a thin iron layer on arrays of cones which are replicated from a porous template. The replicated conic structure itself is of several micrometers and ineffective at antireflection, but the subsequent deposition of iron on top generates nanometer-size columnar structures, and thus broadband absorption enhancement is achieved.

  • 44.
    Apaydin, Dogukan H.
    et al.
    Johannes Kepler University of Linz, Austria.
    Gora, Monika
    University of Warsaw, Poland.
    Portenkirchner, Engelbert
    University of Innsbruck, Austria.
    Oppelt, Kerstin T.
    Johannes Kepler University of Linz, Austria.
    Neugebauer, Helmut
    Johannes Kepler University of Linz, Austria.
    Jakesoya, Marie
    Johannes Kepler University of Linz, Austria.
    Glowacki, Eric D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Kunze-Liebhaeuser, Julia
    University of Innsbruck, Austria.
    Zagorska, Malgorzata
    Warsaw University of Technology, Poland.
    Mieczkowski, Jozef
    University of Warsaw, Poland.
    Serdar Sariciftci, Niyazi
    Johannes Kepler University of Linz, Austria.
    Electrochemical Capture and Release of CO2 in Aqueous Electrolytes Using an Organic Semiconductor Electrode2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 15, 12919-12923 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Developing efficient methods for capture and controlled release of carbon dioxide is crucial to any carbon. capture and utilization technology. Herein we present an approach using an organic. semiconductor electrode to electrochemically capture dissolved CO2 in aqueous electrolytes. The process relies on electrochemical reduction of a thin film of a naphthalene bisimide derivative, 2,7,bis (4-(2- (2-ethylhexyl)thiazol-4-yl)phenyObenzo [lmn][3,8] phenanthroline-1,3,6,8(2H,7H)-tetraone (NBIT). This molecule is specifically tailored to afford one-electron reversible and one-electron quasi-reversible reduction in aqueous conditions while, not dissolving or degrading. The reduced NBIT reacts with CO2 to form a stable aemicarbonate salt, which can be subsequently oxidized electrochemically to release CO2. The semicarbonate structure is confirmed by in situ IR spectroelectrochemistry. This process of capturing and releasing carbon dioxide can be realized in an oxygen-free environment under ambient pressure and temperature, with uptake efficiency for CO2 capture of similar to 2.3 mmol g(-1). This is on par with the best solution-phase amine chemical capture technologies available today.

  • 45. Arabasadi, Z.
    et al.
    Khorasani, M.
    Akhlaghi, Shahin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Fazilat, H.
    Gedde, Ulf W.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Shiri, M. E.
    Prediction and optimization of fireproofing properties of intumescent flame retardant coatings using artificial intelligence techniques2013Inngår i: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 61, 193-199 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multi-structured architecture of artificial intelligence techniques including artificial neural network (ANN), adaptive neuro-fuzzy-inference-system (ANFIS) and genetic algorithm (GA) were developed to predict and optimize the fireproofing properties of a model intumescent flame retardant coating including ammonium polyphosphate, pentaerythritol, melamine, thermoplastic acrylic resin and liquid hydrocarbon resin. By implementing ANN on heat insulation results of coating samples, prepared based on a L16 orthogonal array, mean fireproofing time (MFPT) values were properly predicted. The predicted data were then proved to be valid through performing closeness examinations on fuzzy inference systems results regarding their experimental counterparts. However, the possible deviations tapped into phenomena like foam detachment and char cracking were alleviated by ANFIS modeling embedded with pertinent fuzzy rules based on the sole and associative practical role of used additives. The contribution of each intumescent coating component on the formulation with optimized fireproofing behavior was then explored using GA modeling. A similar optimization procedure was also conducted using conventional Taguchi experimental design but the GA based optimized intumescent coating was found to exhibit higher MFPT value than that suggested by the Taguchi method.

  • 46.
    Arjmand, Mehdi
    et al.
    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.
    Energy Saving in Crude Oil Atmospheric Distillation Columns by Modifying the Vapor Feed Inlet Tray2011Inngår i: Chemical Engineering & Technology, ISSN 0930-7516, E-ISSN 1521-4125, Vol. 34, nr 8, 1359-1367 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimization of a typical crude oil atmospheric distillation unit and reduction of energy conservation were carried out through modifying the implementation and change in the flash zone of the tower. A conventional procedure in such units involves the combination of liquid and vapor product of the prefractionation train surge drum upon introduction to the tower. However, it is theoretically illustrated and represented by simulation means that introducing the vapor feed into the upper stages of the distillation column separately can lead to an energy saving of 12.6% in the condenser duty, an increased liquid-to-gas flow (L/G) at certain points of the column, and hence to a reduction in diameter and investment costs of new tower designs of approximately US$ 0.7 million a(-1). The proposal can be put into practice without the need of additional equipments or additional cost of difficult rerouting the streams. An industrial case study of a steadystate crude oil distillation unit is given by simulation provision of AspenHysys (TM).

  • 47.
    Arjmand, Mehdi
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Liu, Longcheng
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Optimization for energy conservation of crude oil atmospheric distillation columns by modifying vapour feed inlet tray from pre-fractionation train2010Inngår i: 2010 AIChE Annual Meeting, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optimization of a typical crude oil atmospheric distillation unit and reduction of energy conservation were carried out through modifying the implementation and change in the flash zone of the tower. Conventional procedure in such units involves combination of liquid and vapour product of the pre-fractionation train surge drum upon insertion to the tower. However it is theoretically illustrated and represented by simulation means that introducing the vapour feed into the upper stages of the distillation column separately can lead to an energy saving of 12.6% in the condenser duty, increased liquid to gas flow (L/G) at certain points of the column and hence a reduction in diameter and investment costs of new tower designs of approximately 0.7 × 10 6 $/y. The proposal can be put into practice without the need of additional equipments or additional cost of difficult re-routing the streams. An industrial case study of a steady-state crude oil distillation unit is given by simulation provision of AspenHysys™.

  • 48.
    Arvidsson, Martin
    et al.
    Department of Psychology, Stockholm University.
    Skedung, Lisa
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Aikala, Maiju
    Oy Keskuslaboratorio - Centrallaboratorium Ab.
    Danerlöv, Katrin
    YKI Institute for Surface Chemistry.
    Kettle, John
    Oy Keskuslaboratorio - Centrallaboratorium Ab.
    Rutland, Mark
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Berglund, Birgitta
    Department of Psychology, Stockholm University.
    Haptic perception of fine surface texture: Psychophysical interpretation of the multidimensional spaceManuskript (preprint) (Annet vitenskapelig)
  • 49.
    Asiimwe, Savina
    et al.
    Makerere Univ, Sch Biosci, Kampala, Uganda.
    Borg-Karlson, Anna-Karin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Azeem, Muhammad
    Mugisha, Maud Kamatenesi
    Namutebi, Agnes
    Gakunga, Ndukui James
    Chemical composition and Toxicological evaluation of the aqueous leaf extracts of Plectranthus amboinicus Lour: Spreng2014Inngår i: International Journal of Pharmaceutical Science Invention, ISSN 2319-6718, Vol. 3, nr 2, 19-27 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Asiimwe, Savina
    et al.
    Makerere Univ, Sch Biosci, Kampala, Uganda.
    Borg-Karlson, Anna-Karin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Azeem, Muhammad
    Sofrata, Abier Hamed
    Byamukama, Robert
    Mugisha, Maud Kamatenesi
    Namutebi, Agnes
    Chemical composition and antimicrobial evaluation of the essential oil and fractions obtained from Plectranthus amboinicus(Lour.): Spreng traditionally used in the management of HIV/AIDS opportunistic infectionsManuskript (preprint) (Annet vitenskapelig)
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