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  • 1.
    Alsins, J.
    et al.
    University of Uppsala, Department of Physical Chemistry, Uppsala, Sweden.
    Björling, Mikael
    Royal Institute of Technology, Physical Chemistry, Stockholm, Sweden.
    Furó, I.
    Royal Institute of Technology, Physical Chemistry, Stockholm, Sweden.
    Egle, V.
    University of Uppsala, Department of Physical Chemistry, Uppsala, Sweden; Latvian State Inst. of Wood Chem., Riga, Latvia.
    Dimer formation of a stilbenesulphonic acid salt in aqueous solution1999In: Journal of Physical Organic Chemistry, ISSN 0894-3230, E-ISSN 1099-1395, Vol. 12, no 3, p. 171-175Article in journal (Refereed)
    Abstract [en]

    The steady-state and time-resolved fluorescence and 1H NMR spectra of a stilbenesulphonic acid salt, commonly used as an optical brightening agent, was studied as a function of concentration in aqueous solution. The aggregates, formed at higher concentrations, were shown to be predominantly dimers with the central stilbene moieties of the molecules stacked plane-parallel. The equilibrium constant for the dimer formation at 25°C was obtained from both NMR and fluorescence measurements.

  • 2.
    Bergqvist, Ida
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Kemi som pedagogiskt verktyg: En studie som berör barnens utveckling och lärande i förskola2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 3.
    Björling, Mikael
    Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden .
    Interaction between Surfaces with Attached Poly(ethylene oxide) Chains1992In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 25, no 15, p. 3956-3970Article in journal (Refereed)
    Abstract [en]

    The paper presents a self-consistent mean-field lattice theory of the Scheutjens-Fleer type where segments may adapt to temperature and the local environment by changing their distribution among internal states. Some new features are introduced in the theoretical treatment of incompressible systems, and it is demonstrated how the chemical potential may be calculated without reference to a bulk system. The theory is applied to make a qualitative prediction for the interaction between surfaces with grafted poly-(ethylene oxide), or PEO, chains. A simple two-state model for the PEO segments is used. The attractive force between the PEO-covered surfaces in water is predicted to be related to the temperature-dependent solubility of PEO in water. The contributions to the force are illustrated by simple examples. The attractive force does not change monotonically upon changing the graft density. At low coverages a strong bridging attraction is predicted if the surfaces are hydrophobic. As the surfaces become more polar, repulsion sets in at a larger separation and the overall attraction becomes less strong. A calculated, closed, solubility gap for a crude model of micelles of nonionic surfactants is presented.

  • 4.
    Björling, Mikael
    Lunds universitet, Lund.
    Polymers at interfaces: or statistical thermodynamics for chain molecules subjected to constraints1991Doctoral thesis, comprehensive summary (Other academic)
  • 5.
    Björling, Mikael
    Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Using end-confined chains to model end-absorbing, triblock copolymers: 1. Analytical approach1998In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 31, no 25, p. 9026-9032Article in journal (Refereed)
    Abstract [en]

    The bridging attraction, mediated by associative, triblock copolymers with insoluble end blocks and a soluble spacer block, is analyzed using scaling arguments and analytical methods. Adsorbing these associative polymers (APs) onto a single surface, the approach of another, bare, surface results in a strong bridging attraction. When both slit surfaces bear adsorbed APs, the bridging attraction is much weaker. The main contribution is an entropic gain since bridge formation decreases the monomer number density in the crowded region near the surface.

  • 6.
    Björling, Mikael
    et al.
    Physical Chemistry, Department of Chemistry, Royal Institute of Technology, Sweden; Physical Pharmaceutical Chemistry, Uppsala University, Biomedical Center, Uppsala, Sweden; Royal Institute of Technology, Sweden.
    Herslöf-Björling, A.
    Physical Chemistry, Department of Chemistry, Royal Institute of Technology, Sweden; Physical Pharmaceutical Chemistry, Uppsala University, Biomedical Center, Uppsala, Sweden; Uppsala University, Sweden.
    Stilbs, P.
    Physical Chemistry, Department of Chemistry, Royal Institute of Technology, Sweden; Physical Pharmaceutical Chemistry, Uppsala University, Biomedical Center, Uppsala, Sweden; Royal Institute of Technology, Sweden.
    An NMR Self-Diffusion Study of the Interaction between Sodium Hyaluronate and Tetradecyltrimethylammonium Bromide1995In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 28, no 20, p. 6970-6975Article in journal (Refereed)
    Abstract [en]

    A decrease of the NMR self-diffusion coefficient of sodium hyaluronate (NaHy) upon increasing tetradecyltrimethylammonium bromide (TTAB) concentration in 202 mM NaCl (just enough to attain single phase conditions irrespective of the TTAB concentration) is interpreted in terms of the formation of NaHy–TTAB complexes containing several NaHy chains. The complexes are judged to be induced by multiple-site electrostatic condensation of TTAB micelles onto the Hy chains. Thus, the TTAB micelles may act as bridging points between, and within, the NaHy chains. For a 1% wt NaHy solution, at 202 mM NaCl, the fraction of adsorbed TTAB has a maximum at 10 mM TTAB where an estimated 54% of all the added TTAB is bound. At 70 mM TTAB, the fraction of bound TTAB has decreased to 42%. The decrease of the binding constant with increasing TTAB concentration is attributed to a more efficient electrostatic screening; i.e., the ionic strength (due to uncondensed species) increases. The observed NaHy–TTAB complexes are likely to be precursors of the precipitated phase formed at lower salt concentrations.

  • 7.
    Björling, Mikael
    et al.
    Physical Chemistry 1, Chemical Center, Lund, Sweden.
    Karlström, G.
    Physical Chemistry 1, Chemical Center, Lund, Sweden; Theoretical Chemistry, Chemical Center, Lund, Sweden.
    Linse, P.
    Physical Chemistry 1, Chemical Center, Lund, Sweden.
    Conformational adaption of poly(ethylene oxide). A 13C NMR study1991In: Journal of Physical Chemistry, ISSN 0022-3654, Vol. 95, no 17, p. 6706-6709Article in journal (Refereed)
    Abstract [en]

    The 13C NMR chemical shift was used as a probe for the average partition of rotational conformers around the C-C bond in the O-CH2-CH2-O segments of polyethylene oxide). Dividing the conformers into a large group of trans and a smaller group of gauche conformers, we concluded that the trans conformers have a higher (downfield) average chemical shift than the gauche conformers. The shift of the main PEO 13C line with changing environment was interpreted as an adaption in the partition between the two groups of conformers. Furthermore, the trans conformers had nonpolar character and were favored at high temperatures, whereas the gauche conformers had polar character. The measurements were compared to the predictions of a model proposed by Karlström, and a semiquantitative agreement was found.

  • 8.
    Björling, Mikael
    et al.
    Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden; Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Linse, P.
    Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden.
    Self-consistent-field theory for hard-sphere chains close to hard walls1992In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 97, no 9, p. 6890-6900Article in journal (Refereed)
    Abstract [en]

    A continuum theory for confined hard-sphere polymers is presented. Starting from fundamental relations and applying defined approximations, a constitutive relation for the conformation probability (analogous to the result in mean-field lattice theories) is developed. The main problem of hard-sphere correlations is attacked by two approximate methods: First, using the Carnahan-Starling equation of state and local volume fractions (CS). Second, by an extension of the lattice theory to spherical components with unequal volumes (LATT). The agreement with Monte Carlo simulations is good for both approximations at low densities, but becomes only qualitative at the higher concentrations. The CS approximation seems to be favored over the LATT approach at the higher concentrations when correlation becomes more important. Both free and grafted chains are treated. The influence of chain length, grafting density, solvent concentration, solvent chain length, and surface curvature on the segment distribution is investigated.

  • 9.
    Björling, Mikael
    et al.
    Division of Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden.
    Linse, P.
    Division of Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden.
    Karlström, G.
    Division of Theoretical Chemistry, Chemical Center, University of Lund, Lund, Sweden.
    Distribution of segments for terminally attached poly(ethylene oxide) chains1990In: Journal of Physical Chemistry, ISSN 0022-3654, Vol. 94, no 1, p. 471-481Article in journal (Refereed)
    Abstract [en]

    A theory for describing the equilibrium ethylene oxide (EO) segment distribution for terminally attached poly(ethylene oxide) (PEO) chains is presented. It is based on Scheutjens and Fleer's lattice model for polymer solutions in heterogeneous systems and a two-state model for the EO segments. The two-state model provides one explanation of the solubility gap of homogeneous PEO solutions. The segment distribution is examined as a function of temperature, grafting density, and curvature. The present theory predicts distributions, which cannot be reproduced with the use of temperature-dependent interaction parameters in a one-state model. Specifically, the segments tend to be more accumulated at the surface but also far away from the surface at the expense of the intervening transition region. Calculation on a model of a micelles formed by the nonionic surfactant C 12E 8 supports the experimental conclusions that the EO segments are preferentially accumulated nearby the hydrocarbon core and not completely extended into the water region.

  • 10.
    Björling, Mikael
    et al.
    Royal Institute of Technology, Physical Chemistry, Stockholm, Sweden.
    Pellicane, G.
    Dipartimento di Fisica, Sez. Teorica, Messina, Italy; Ist. Nazionale Fisica della Materia, Messina, Italy.
    Caccamo, C.
    Dipartimento di Fisica, Sez. Teorica, Messina, Italy; Ist. Nazionale Fisica della Materia, Messina, Italy.
    On the application of Flory-Huggins and integral equation theories to asymmetric hard sphere mixtures1999In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 111, no 15, p. 6884-6889Article in journal (Refereed)
    Abstract [en]

    Flory-Huggins (FH) and integral equation theories (IETs) are used to describe the equation of state and the relevant mixing properties of hard sphere binary mixtures in the limit of high size-asymmetry. The results are compared with those obtained from the heuristic equation of state of Mansoori et al. (BMCSL) [J. Chem. Phys. 54, 1523 (1971)] and with the Flory-Huggins scheme of other authors. By choosing a physical recipe for the volume fractions of the two species in the mixture FH theory is shown to be a good approximation to the entropy and the Gibbs free energy of mixing, which shows improvement at high size-asymmetry. In addition, the results of the IETs are found to be in overall quantitative agreement with BMCSL. The implications of our study concerning colloidal systems are discussed.

  • 11.
    Björling, Mikael
    et al.
    Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Stilbs, P.
    Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Using end-confined chains to model end-absorbing, triblock copolymers: 2. Numerical approach1998In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 31, no 25, p. 9033-9043Article in journal (Refereed)
    Abstract [en]

    The bridging attraction mediated by end-absorbing, triblock copolymers in a good solvent is analyzed using numerical methods and compared to analytical results. Good agreement is found. The main deviations may be attributed to the neglect of thermal fluctuations in the extension of the loops at the brush edge in the analytical treatment. With a suitable choice of "natural" units, the numerical results for the bridging probability and the free energy of interaction per chain collapse onto universal master curves in the two arrangements considered: symmetric and asymmetric adsorption of associative polymers (APs) on the surfaces of a planar slit.

  • 12.
    Bustad, Johnny
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    CO Adsorption on Cu(l00) Systems: A Theoretical Shake-Up Study1996Report (Other academic)
  • 13.
    Bustad, Johnny
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Shake-Up Structures Calculated with the INDO/CI Method: CO Adsorbed on Ni(100) Clusters1996Report (Other academic)
    Abstract [en]

    In the chemisorption system CO/Ni(100), a comparison between available high resolution core level photoelectron spectra and spectra calculated by the INDO/CI method done for different nickel cluster sizes. A reassignment of some of the satellites is made. It is found that the asymmetry and the broadening of the main line mainly depends on substrate-substrate excitations, predominantly from the d-band to the s-band within the nickelsubstrate.

  • 14.
    Bustad, Johnny
    University of Gävle, Department of Mathematics, Natural and Computer Sciences. Natur.
    Shake-up studies of model systems for adsorbates: Department of Quantum Chemistry, Uppsala University1993Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    Shake-up studies of model systems for adsorbates are presented. The molecule CO adsorbed on transition metal surfaces belong to one of the most studied systems in surface science. The interest is motivated by fundamental questions about the adsorbate-substrate interaction as well as technical applications, such as catalysis. A good starting point in order to get more detailed understanding of the CO-metal interaction is to study the transition metal carbonyls, where CO is coordinated to metal atoms. It has been found that many aspects of the adsorbate systems can be modelled by these molecules. These are the main reasons for studying the molecules Mo(CO)6 and Cr(CO)6, for which results are reported in this thesis.

  • 15.
    Bustad, Johnny
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Theoretical Shake-Up Studies of N2 Adsorbed on Ni(100) Clusters1996Report (Other academic)
  • 16.
    Bustad, Johnny
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Lunell, Sten
    Semi-Empirical Configurational Interaction Calculations of XPS Shake-Up Satellites in Ni(CO)41996Report (Other academic)
  • 17.
    Domanders, Sofie
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Kemi i förskolan2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna undersökning har som syfte att ta reda på vad barnen i förskolan anser om att delta i kemiexperiment och vad som händer i barngruppen under experimenten. För att studera dessa frågor har jag gjort observationer med hjälp av videokamera och intervjuer av barnen som deltagit i experimenten. Barnen har visat stort intresse, engagemang, glädje och nyfikenhet vilket har genomsyrat experimenttillfällena. Resultaten i denna undersökning visar att kemiexperiment kan vara ett bra verktyg i förskolan. Barnen interagerar med varandra, associerar till tidigare erfarenheter i livet och ger uttryck för att uppleva, med många av sina sinnen.

     

     

  • 18.
    Halle, B.
    et al.
    Condensed Matter Magnetic Resonance Group, Lund University, Chemical Center, Lund, Sweden.
    Björling, Mikael
    Laboratoire S.R.S.I., U.R.A. C.N.R.S. 1662, Université P. et M. Curie, Paris, France; Division of Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Microemulsions as macroelectrolytes1995In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 103, no 4, p. 1655-1668Article in journal (Refereed)
    Abstract [en]

    Water-in-oil microemulsions, composed of discrete aqueous droplets dispersed in a continuous oil medium, constitute a special class of electrolyte solutions. Such macroelectrolytes are analogous to conventional electrolyte solutions in most respects, with the notable difference that, in a microemulsion, the ionic (droplet) charge is not fixed but depends on the droplet interactions. Describing the microemulsion as a primitive-model electrolyte mixture with ions of variable charge and evaluating the statistical mechanics within the mean-spherical approximation (MSA), we construct a self-consistent theory of charge fluctuations and droplet interactions in ionic microemulsions. The droplet charge distribution is calculated as a function of the size, shape, polydispersity, and volume fraction of the droplets. We argue that the net droplet charges can have a decisive influence on microemulsion structure, especially at the higher volume fractions where clustering and spinodal decomposition are observed. At lower volume fractions, where the MSA treatment should be quantitatively accurate, the Coulomb interaction between charged droplets has no effect on the structure factor deduced from scattering data.

  • 19.
    Herslöf-Björling, Å.
    et al.
    Physical Pharmaceutical Chemistry, Uppsala University, Biomedical Center, Uppsala, Sweden; Medical Products Agency, Uppsala, Sweden.
    Björling, Mikael
    Physical Chemistry, Department of Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Sundelöf, L.-O.
    Physical Pharmaceutical Chemistry, Uppsala University, Biomedical Center, Uppsala, Sweden.
    The Counter- and Colon Influence on the Interaction between Sodium Hyaluronate and Tetradecyltrimethylammonium Bromide1999In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 15, no 2, p. 353-357Article in journal (Refereed)
    Abstract [en]

    The minimum concentration of salt (critical electrolyte concentration, CEC) required to suppress precipitation/coacervation in an aqueous solution of sodium hyaluronate (NaHy) and tetradecyltrimethylammonium bromide (TTAB) has been studied and CEC diagrams constructed for a set of inorganic salts, as a function of TTAB concentration. An initial rapid increase in the CEC is observed for low TTAB concentrations at the onset of the coacervation region. When the TTAB concentration is increased, a CEC plateau is reached at a certain TTAB concentration. Thereafter, the CEC value stays fairly constant, independent of TTAB concentration, until finally the CEC value starts to decrease at a sufficiently high TTAB concentration. The CEC plateau value and the onset of the decrease of CEC are shown to depend strongly on the valence of the ions constituting the salt. For ions of equal valency, ion-specific effects are observed.

  • 20.
    King, George A
    et al.
    CSIRO-DBCE.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    A Methodology for Quantifying the Atmospheric Corrosion Performance of Fabricated Metal Products in Marine Environments2000In: Marine Corrosion in Tropical Environments, West Conshohocken, PA: American Society for Testing and Materials , 2000, p. 114-132Chapter in book (Refereed)
    Abstract [en]

    In Australia a long-term project is studying the marine atmospheric corrosion performance of several metals and alloys, and a range of generic classes of coatings and finishes (metallic and organic) on steel and aluminum. Specimens have been exposed for over nine years at three marine sites, both in the open and under a specially designed glass shelter which has greatly accelerated deterioration. The sheet product test pieces include a range of features designed to simulate the types of distress introduced during manufacture and building, and at which corrosion defects initially manifest. A methodology is described for the development of quantitative performance indices for these formed specimens. The general philosophy involves using the collected data to determine appropriate weighting to different types of defects on features, or to the relative contribution of different features to overall defect indices and in turn their relative contribution to a total performance index. A rigorous mathematical procedure was followed to calculate defect indices and total performance indices for all products. Some results for the two-year specimens are discussed.

  • 21.
    Kus, Hulya
    et al.
    Institutionen för teknik och byggd miljö.
    Marteinsson, Björn
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Temperature and moisture conditions in materials: effects on risk for degradation of rendered autoclaved aerated concrete2005In: Paper TT1-107, 2005, p. 60-67Conference paper (Other academic)
    Abstract [en]

    Temperature and moisture conditions are, in general, the two major factors influencing the long-term performance of external walls made of porous mineral building materials. Degradation of wall components is accelerated by temperature and moisture induced stresses which lead to cracks and in turn a surface more vulnerable to other degradation agents. The degradation rate depends on both the environmental conditions and the material-inherent and component design properties. Extreme and rapid temperature fluctuations as well as moderate diurnal and seasonal temperature cycles cause thermal stresses and strains in the material, resulting in expansion or contraction and eventual deformation such as cracking or fracture. Material properties such as thermal expansion, elasticity and tensile strength determine if cracking occurs either immeadiately when the surface temperature drops below the initial temperature after rapid cooling or after a period of time if alternating or repeated stresses result in creep and fatigue.

    In this paper an attempt is made to evaluate the temperature effects on the risk for degradation of external walls made of rendered autoclaved aerated concrete (AAC) based on temperature measurement data and the material properties. The measurement results are obtained from the continuous microenvironment monitoring carried out on a test cabin built on the roof of the Centre for Built Environment building in Gävle, Sweden. A finite element model (FEM) is used to simply calculate the temperature induced stresses in two different cases; with and without creep and relaxation in the material. According to the microenvironment measurement results the test panels attain maximum surface temperatures up to about 60 °C during summer and experience surface temperature fluctuations between day and night up to about 55 °C during winter. Rapid changes in surface temperatures frequently occur particularly throughout late spring and early summer. The preliminary calculated results indicate that the tensile forces built up during cold spells may be sufficient to crack the surface of AAC panels but the risk for fatigue damages due to combined moisture and temperature cycles induced by radiation from the sun seems to be small. Further studies are needed for better knowledge and reliable information on the degradation mechanisms related to temperature by complementary measurements of stress-strain, stress relaxation, creep and fatigue behaviour of AAC panels under different and cyclic temperature loading.

  • 22. Kus, Hulya
    et al.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Monitoring of moisture in rendered autoclaved aerated concrete wall by nail electrodes2001In: The international conference on building envelope systems and technologies (ICBEST) 2001, Vol 1, 2001, p. 237-242Conference paper (Other academic)
  • 23.
    Kus, Hulya
    et al.
    University of Gävle, Department of Technology and Built Environment.
    Nygren, Kjell
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    In-use performance of rendered autoclaved aerated concrete walls by long-term moisture monitoring2004In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 39, no 6, p. 677-687Article in journal (Refereed)
    Abstract [en]

    The importance of long-term performance and durability of building materials and components has received increasing consideration with regard to a sustainable built environment. Degradation due to exposure to environment conditions, particularly driving rain, play a significant role in the service life of porous materials used in external wall components. Microenvironment monitoring data are presented in this paper to show how different surface coatings can contribute to moisture performance of external walls made of autoclaved aerated concrete (AAC). Renderings modifed with hydrophobic products on AAC substrate prove to have less wetting and better drying properties than unmodified renderings according to the performance assessment based on the amount and duration of moisture measured in the material.

  • 24.
    Lefez, B.
    et al.
    Laboratoire D'analyse, Université de Rouen, Mont Saint Aignan, France.
    Kartouni, K.
    Laboratoire D'analyse, Université de Rouen, Mont Saint Aignan, France.
    Lenglet, M.
    Laboratoire D'analyse, Université de Rouen, Mont Saint Aignan, France.
    Rönnow, Daniel
    Institute of Technology, Uppsala University, Uppsala, Sweden.
    Ribbing, C. G.
    Institute of Technology, Uppsala University, Uppsala, Sweden.
    Application of reflectance spectrophotometry to the study of copper (I) oxides (Cu2O and Cu3O2) on metallic substrate1994In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 22, no 1-12, p. 451-455Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to characterize the compounds grown on copper during the oxidation at low temperature (T < 523 K) by optical methods: photoluminescence and UV‐Visible‐NIR diffuse reflectance spectroscopy. Two cuprous oxides Cu2O and Cu3O2 have been studied. The absorption of Cu2O films in the range 450–630 nm is mainly due to non‐stoichiometry bands associated with copper and oxygen vacancies. Cu3O2 is characterized by an optical band gap greater than that of Cu2O (respectively 2.25 and 1.95 eV) and by an intense luminescence emission at 760–780 nm. Cu3O2 may be considered as a gross defect structure of Cu2O (a Cu 2O = 0.427 nm, a Cu 3O 2 = 0.431 nm). The experimental approach of the oxidation mechanism reveals that at 423 K Cu2O is the primary product which later on is transformed into Cu3O2. Experimental and calculated optical absorption curves disclose the nucleation of CuO inside the cuprous oxides layer for oxidation in the range 473–523 K.

  • 25.
    Linse, Per
    et al.
    Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden .
    Björling, Mikael
    Physical Chemistry 1, Chemical Center, University of Lund, Lund, Sweden .
    Lattice Theory for Multicomponent Mixtures of Copolymers with Internal Degrees of Freedom in Heterogeneous Systems1991In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 24, no 25, p. 6700-6711Article in journal (Refereed)
    Abstract [en]

    We have generalized the lattice theory recently presented by Evers, Scheutjens, and Fleer (Macromolecules 1990, 23, 5221) by extending it to the case where the polymer segments possess internal degrees of freedom. The theory is able to describe the adsorption from a multicomponent mixture of arbitrary composition of polymers and solvents where the segments of a polymer may be of different types and possess internal degrees of freedom. The use of internal states results in effective segment-segment interaction parameters, which are temperature and density dependent. This simple polymer model has previously been useful for describing the existence of a lower consolute point occurring in some aqueous polymer solutions and for predicting the conformational equilibrium of poly(ethylene oxide) in homogeneous solutions. We also present results from an application of our extended theory on the adsorption of Pluronic (a triblock copolymer) from aqueous solution. The nontrivial and prominent increase of the Pluronic adsorption as the temperature of the solution reaches the cloud point from below is accurately reproduced by the theory.

  • 26.
    Lisiecki, I.
    et al.
    Laboratoire SRSI, Universite Pierre et Marie Curie, Paris, France; CEN Saclay, DRECAM-SCM Bat 522, Gifsur Yvette, France; Depagrtment of Applied Mathematics, Canberra, Australia; Universite Pierre et Marie Curie, France; CEN Saclay, France.
    Bjorling, Mikael
    Laboratoire SRSI, Universite Pierre et Marie Curie, Paris, France; CEN Saclay, DRECAM-SCM Bat 522, Gifsur Yvette, France; Depagrtment of Applied Mathematics, Canberra, Australia; Universite Pierre et Marie Curie, France; CEN Saclay, France.
    Motte, L.
    Laboratoire SRSI, Universite Pierre et Marie Curie, Paris, France; CEN Saclay, DRECAM-SCM Bat 522, Gifsur Yvette, France; Depagrtment of Applied Mathematics, Canberra, Australia; Universite Pierre et Marie Curie, France; CEN Saclay, France.
    Ninham, B.
    Laboratoire SRSI, Universite Pierre et Marie Curie, Paris, France; CEN Saclay, DRECAM-SCM Bat 522, Gifsur Yvette, France; Depagrtment of Applied Mathematics, Canberra, Australia.
    Pileni, M. P.
    Laboratoire SRSI, Universite Pierre et Marie Curie, Paris, France; CEN Saclay, DRECAM-SCM Bat 522, Gifsur Yvette, France; Depagrtment of Applied Mathematics, Canberra, Australia; Universite Pierre et Marie Curie, France; CEN Saclay, France; Department of Applied Mathematics, France.
    Synthesis of Copper Nanosize Particles in Anionic Reverse Micelles: Effect of the Addition of a Cationic Surfactant on the Size of the Crystallites1995In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 11, no 7, p. 2385-2392Article in journal (Refereed)
    Abstract [en]

    The size of copper nanoparticles in reverse micelles can be controlled by varying the water content of anionic reverse micelles (AOT = sodium bis(2-ethylhexyl)sulfosuccinate). In the presence of cetyltrim-ethylammonium chloride (CTAC), depending on the concentration, the size of the particles is strongly affected. At a low CTAC concentration ([CTAC] = 4 × 10-4 M), an unexpectedly large increase in the size is observed. At the other extreme, a decrease in the size is observed at higher CTAC concentration ([CTAC] = 6.4 × 10-3 M). The increase in the size at low CTAC concentration could be explained in terms of the formation of superaggregates containing most of the cationic surfactant. At higher CTAC concentrations, a random distribution of the positively charged surfactant takes place and the decrease in the size could be due to a decreasein the intermicellar attraction. Furthermore, the yield of particles drastically increases which is attributed to a change in the redox potential.

  • 27.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Surface Moisture and Time of Wetness Measurements2002In: Service Life Prediction: Methodology and Metrologies, Washington, DC: American Chemical Society , 2002, p. 23-36Chapter in book (Refereed)
    Abstract [en]

    Surface moisture plays an important role in the deterioration of building surfaces. The extent and duration of surface moisture is generally impossible to predict from meteorological data. The limitations of the ISO 9223 standard for estimating the time of wetness (TOW; RH>80%, T>0°C) is evident in climates with sub-zero temperatures, in environments with significant deposition of pollutants and salt, and in situations where the exchange of radiation between building surfaces and the surrounding environment creates large temperature differences. Consequently, direct measurement of TOW is essential, e.g. using the WETCORR method. This method is suitable for measurements of surface moisture and TOW on building materials in general. The actual sensor consists of an inert electrolytic cell with Au/Au-electrodes combined with a Pt-1000 surface temperature-sensing element.

  • 28.
    Norberg, Peter
    et al.
    University of Gävle, Department of Technology and Built Environment.
    Lindahl, Lars G
    Abrahamsson, Jörgen
    University of Gävle, Department of Technology and Built Environment.
    En metod för framställning av agglomerat av utfällt silikamaterial, ett mikroporöst material innefattande sådan agglomerat och användning därav2007Patent (Other (popular science, discussion, etc.))
    Abstract [sv]

    Föreliggande uppfinning avser en metod att producera ett material som innefattar agglomererade partiklar av utfälld kiseldioxid, innefattande framställning av en lösning av åtminstone ett metallsalt (M), där metalljonen/-jonerna är tvåvärd(a) eller flervärd(a). En lösning av alkalimetall (M) silikat med ett molförhållande SiO2/M2O om 0.5 - 100 framställs. Lösningarna blandas och blandningen omrörs, och ett koagel tillåts bildas. Koaglet uppsamlas och behandlas för att tillhandahålla ett material som har en torrsubstans om >15, företrädesvis >97%. Ett material som kan erhållas med processen tillhandahålles också.

  • 29.
    Söderlind, E.
    et al.
    Department of Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Björling, M.
    Department of Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Stilbs, P.
    Department of Physical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Molecular Mobility and Order of Didodecyldimethylammonium Chloride Adsorbed on Silica Particles from 2H Nuclear Spin Relaxation1994In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 10, no 3, p. 890-898Article in journal (Refereed)
    Abstract [en]

    Didodecyldimethylammonium chloride (DDAC) was adsorbed onto two different silicas with different particle radii at pH 10. Bulk adsorption studies for Cab-O-Sil M5 suggest that the surfactant forms a complete bilayer on the solid surface, as judged from the observed plateau adsorption level (Γ = 1.25 mmol/g) and the calculated surface density. In order to further elucidate the structure and dynamics of the adsorbed surfactant, 2H NMR studies on selectively labeled DDAC (DDAC-d6, deuterium labeled in the nitrogen bound methyls) were undertaken. Spectra and spin relaxation parameters were recorded for the surfactant adsorbed on silica, in reference to those for DDAC-d6 dispersed in water and in lamellar liquid crystals. These studies reveal that the exchange between the solid surface and solution is slow on the pertinent NMR time scale. For DDAC-d6 adsorbed on large particles a quadrupole splitting corresponding to an order parameter of SDF = 0.0156 is clearly visible. Longitudinal (T1) spin relaxation measurements at different temperatures are consistent with a higher degree of motional constraints in the adsorbed state, as compared to the dissolved state. Transverse (T2) spin relaxation measurements and the observed deuterium bandshapes point to the existence of modes of slow molecular motions. An attempt was made to characterize these slow motions further, by studying the dependence of T on the pulse dispersion in the quadrupolar CPMG (Q-CPMG) pulse sequence. The correlation time for slow molecular motions so-obtained suggests that additional modes of slow motions are more important for adsorbed DDAC-d6 than for aggregates in solution, the most likely candidate being related to motions caused by a mismatch of the preferred structure of the surfactant bilayer and the silica surface.

  • 30.
    Twumasi, Ebenezer
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Forslund, Mikael
    Norberg, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Sjöström, Christer
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Textural and adsorption properties of a carbon-silica composite adsorbent for air filtration2010In: World Journal of Engineering, ISSN 1708-5284, Vol. 7, no 2, p. 227-228Article in journal (Other academic)
  • 31.
    Twumasi, Ebenezer
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Norberg, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Forslund, Mikael
    Materials Technology KTH Reserch School.
    Sjöström, Christer
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Carbon–silica composites prepared by the precipitation method: Effect of the synthesis parameters on textural characteristics and toluene dynamic adsorption2012In: Journal of porous materials, ISSN 1380-2224, E-ISSN 1573-4854, Vol. 19, no 3, p. 333-343Article in journal (Refereed)
    Abstract [en]

    Three synthesis routes are presented here that leads to carbon–silica composites. These were characterized by nitrogen physisorption, by thermogravimetric analysis and by dynamic toluene adsorption test similar to Ashrae standard I45.1. The carbon–silica composites possess high microporosity and mesoporosity as well as large surface areas. Furthermore, the control of the microporosity as well as pore size distribution is possible because they depend on the amount of carbon used and of the synthesis route. Following routes I and III a wide micro-mesoporous pore size (1–32 nm) was obtained where as by route II narrow micro-mesoporous pore size (1–4 nm) was observed. In addition, pore diameters center in the range of 1.13–1.17 nm was observed when carbon content was 32 or 45 wt%. The dynamic adsorption of toluene was evaluated for carbon–silica composites obtained by three preparation routes at two different carbon contents, 32 and 45 wt%. The results showed that a composite with 45 wt% carbon content and obtained via preparation route I gave the highest toluene adsorption capacity (27.6 wt% relative to carbon content). The large uptake capacity of this composite was attributed to the presence of high microporosity volume and a wide (1–32 nm) bimodal pore system consisting of extensive mesopore channels (2–32 nm) as well as large surface area. These capacity values of carbon–silica composites are by weight relative to carbon content and are competitive to, results obtained for commercial coconut activated carbon (31.1 wt%) and significantly better than a commercial alumina-carbon composite(9.5 wt%) at 0% efficiency.

  • 32.
    Wahlborg, Dan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Björling, Mikael
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Andersson, Lars T.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Allergenic potency of birch pollen2016In: Indoor Air 2016: The 14th International Conference of Indoor Air Quality and Climate, July 3-8 2016, Ghent, Belgium. Conference Proceedings / [ed] E. Van Kenhove, J. Laverge, P. De Vlieger, ISIAQ , 2016, article id 553Conference paper (Refereed)
    Abstract [en]

    The number of people sensitized to the major birch pollen allergen Bet v 1 in industrialized countries is vast and still rising. The purpose of this study was to develop a method with sensitivity high enough to measure the Bet v 1 content of a few birch pollen grains without the interference of environmental factors such as diesel particles, ozone level, humidity, temperature and precipitation. Grains were collected from catkins at two locations in Sweden over a period of 5 years. Allergens were extracted over polytetrafluoroethylene (PTFE) filters and Bet v 1 quantification was made with a luminescence immunoassay. The average content of Bet v 1 was 3.6 ± 0.6 pg per pollen grain for samples collected in three different pollination seasons. This is the first in a series of controlled experiments on the release of the major allergen Bet v 1 from birch pollen grains.

  • 33.
    Wang, Zhao
    et al.
    KTH, Kemisk apparatteknik.
    Liu, Longcheng
    KTH, Kemisk apparatteknik.
    Hard-sphere fluid-mediated interaction: a novel pressure expression with application of the weighted correlation approachIn: Article in journal (Other academic)
  • 34.
    Wang, Zhao
    et al.
    KTH, Kemisk apparatteknik.
    Liu, Longcheng
    KTH, Kemisk apparatteknik.
    The swelling pressure of Na-bentonite: Study with a density functional approach2012In: Chemistry Letters, ISSN 0366-7022, E-ISSN 1348-0715, Vol. 41, no 10, p. 1346-1348Article in journal (Refereed)
    Abstract [en]

    The combination of the fundamental measure theory (FMT) and the weighted correlation approach (WCA) within the framework of the density functional theory, i.e., the FMT/ WCA approach, is applied to study the swelling pressure of Nabentonite at different salt conditions. Good agreement between the FMT/WCA simulations and the results from both experiments and a Donnan-equilibrium-based DLVO model suggests that the hydration repulsion between charged surfaces can be well accounted by the ionion correlations effect.

  • 35.
    Wang, Zhao
    et al.
    KTH.
    Liu, Longcheng
    KTH, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Kemisk apparatteknik.
    A novel method to describe the interaction pressure between charged plates with application of the weighted correlation approach2011In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 135, no 24, p. 244107-Article in journal (Refereed)
    Abstract [en]

    Based on the Euler-Lagrange equation for ion density distribution in an inhomogeneous, charged, and hard-sphere fluid, a novel method is proposed to determine the interaction pressure between charged plates. The resulting expression is a sum of distinct physical contributions to the pressure, which involves different contributions to the single-particle direct correlation function. It can, therefore, be conveniently used in any density functional approach to facilitate analysis of the pressure components. In this study, the so-called fundamental measure theory (FMT)/weighted correlation approach (WCA) approach is applied to estimate both the hard-sphere and the electric residual contributions to the single-particle direct correlation function, upon the calculation of the ionic density profiles between charged plates. The results, against the Monte Carlo simulations, show that the FMT/WCA approach is superior to the typical FMT/mean spherical approximation approach of the density functional theory in predicting the interaction pressure between charged plates immersed in an electrolyte solution upon various conditions in the primitive model. The FMT/WCA approach can well capture the fine features of the pressure-separation dependence, to reproduce not only the shoulder shape and the weak attractions in monovalent electrolytes but also the strongly oscillatory behavior of pressure in divalent electrolytes where pronounced attractions are observed. In addition, it is found that the FMT/WCA approach even has an advantage over the anisotropic, hyper-netted chain approach in that it agrees with the Monte Carlo results to a very good extent with, however, much less computational effort.

1 - 35 of 35
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