References of "1996"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailTelechelic ionomers studied by light scattering and dynamic mechanical measurements
Chassenieux, Christophe; Johannsson, Ragnar; Durand, Dominique et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (1996), 112(2-3), 155-162

The formation of a transient network by sulfonato polyisoprene and sulfonato polystyrene in toluene is studied using static and dynamic light scattering and dynamic mechanical analysis. It is shown that ... [more ▼]

The formation of a transient network by sulfonato polyisoprene and sulfonato polystyrene in toluene is studied using static and dynamic light scattering and dynamic mechanical analysis. It is shown that at low concentrations aggregates are formed with increasing molar mass and polydispersity as the polymer concentration is increased. Above a certain concentration well below the overlap concentration of the polymer chains (C*), a transient network is formed. This is characterised by a plateau modulus at high frequencies and a relatively narrow viscoelastic relaxation time distribution. The intensity auto-correlation function of the transient network shows two relaxational modes: a relatively fast diffusional mode close to the co-operative diffusional mode of semidilute solutions of the unfunctionalised polymers, and a slow broader mode which becomes independent of the scattering angle at concentrations close to C*. The relation between this slow mode and the viscoelastic relaxation is discussed. [less ▲]

Detailed reference viewed: 40 (1 ULg)
Full Text
Peer Reviewed
See detailTriblock copolymer based thermoreversible gels. 2. Analysis of the sol-gel transition
Yu, Jian Ming; Dubois, Philippe ULg; Teyssié, Philippe et al

in Macromolecules (1996), 29(16), 5384-5391

Syndiotactic poly(methyl methacrylate) (sPMMA)−polybutadiene (PBD)−sPMMA triblock copolymers of various chemical compositions and different molecular weights have been studied in the presence of o-xylene ... [more ▼]

Syndiotactic poly(methyl methacrylate) (sPMMA)−polybutadiene (PBD)−sPMMA triblock copolymers of various chemical compositions and different molecular weights have been studied in the presence of o-xylene, which is a selective solvent for the central PBD block. Thermoreversible gels can be formed in a suitable curing temperature range (<35 °C) and at a high enough concentration (>1 wt %). The time dependence of the storage (G‘) and the loss (G‘‘) moduli has been measured in a frequency range of 0.08−1 Hz. The static and dynamic properties of the gels have been discussed on the basis of the scaling theory. At the gel point, where the loss angle (tan δc = G‘‘/G‘) is independent of frequency, typical power laws G‘(ω) G‘‘(ω) ωΔ have been observed. The scaling exponent Δ has been found equal to 0.70 ± 0.02 independently of the PBD and PMMA molecular weight, i.e., 36 000 < Mn (PBD) < 100 000 and 20 000 < Mn (PMMA) < 51 000. This exponent is also independent of the copolymer concentration and temperature in the investigated range, i.e., 2−7 wt % and 8−24 °C, respectively. This value of Δ agrees with theoretical predictions as well as with experimental values reported for some chemical gels; it is however different from the experimental values published for most physical gels. A PBD−PMMA diblock copolymer also forms a gel in o-xylene, although at higher concentration and lower temperature compared to the parent triblock copolymer. The scaling exponent Δ is then somewhat smaller, i.e., 0.61. [less ▲]

Detailed reference viewed: 29 (5 ULg)
Full Text
See detailTransition metal aerogel-supported catalyst
Heinrichs, Benoît ULg; Pirard, Jean-Paul ULg; Pirard, René ULg

Patent (1996)

A process for preparing a supported catalyst comprising a transition metal selected from palladium, platinum, nickel, cobalt or copper on an aerogel support, which includes the steps of providing a ... [more ▼]

A process for preparing a supported catalyst comprising a transition metal selected from palladium, platinum, nickel, cobalt or copper on an aerogel support, which includes the steps of providing a mixture containing an alkoxide precursor of the aerogel, a chelate complex of the transition metal with a chelating agent having Si(OR)3 anchor groups, and an organic solvent in which the chelate complex is soluble; hydrolyzing the mixture by admixing it with water to form a gel; and converting the gel under supercritical conditions into the transition metal aerogel-supported catalyst. The supported catalyst has an especially homogeneous distribution of the metal component and is suitable, for example, for use as a hydrogenation catalyst. [less ▲]

Detailed reference viewed: 47 (34 ULg)
Full Text
Peer Reviewed
See detailA Global Understanding of Transient Surface Flows Applied to Hydrology and River Processes
Pirotton, Michel ULg

in XI International Conference on Computational Methods in Water Resources (1996, July 22)

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailTraining the rehearsal strategy in Down syndrome and normal children. Effects on memory span, word-length and phonological similarity effect
Comblain, Annick ULg

Poster (1996, July 18)

Verbal short-term memory skills of Down's syndrome subjects are very poor. As in normal children, it seems possible to increase memory span by using a rehearsal training strategy. Memory span tasks have ... [more ▼]

Verbal short-term memory skills of Down's syndrome subjects are very poor. As in normal children, it seems possible to increase memory span by using a rehearsal training strategy. Memory span tasks have been proposed to two experimental groups (Down's syndrome subjects / normally developping children) and two control groups (Down's syndrome subjects / normally developping children). The experimental groups were intensively trained to rehearse during 8 weeks. Two post-tests were proposed to the subjects: 1] directly after the training session and 2] six weeks after the training session. We observe an increase of the experimental groups' memory span. The weak modifications of word-length effect and phonological similarity effect seem to confirm that these effects are not due to the rehearsal strategy use. [less ▲]

Detailed reference viewed: 35 (0 ULg)
See detailModeling the Structural Behavior in Case of Fire
Franssen, Jean-Marc ULg

Scientific conference (1996, July 15)

Detailed reference viewed: 5 (1 ULg)
Peer Reviewed
See detailInner patterns and front propagation of dynamic random impurity model
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg

in Physical Review Letters (1996), 77(3), 510-513

We investigate a simple model, the so-called dynamic epidemic model, for the evolution of an advancing interface through a medium containing mobile impurities. A short range repulsion between the front ... [more ▼]

We investigate a simple model, the so-called dynamic epidemic model, for the evolution of an advancing interface through a medium containing mobile impurities. A short range repulsion between the front and the impurities leads to an aggregation process along the front, and to the trapping of aggregates. The amplitude of this self-organization for collective impurity trapping is analyzed in two dimensions. A relationship exists between individual motion and the aggregation of particles. The results indicate that self-organizing features are different behind and on the front. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailDiblock Copolymers as Emulsifying Agents in Polymer Blends: Influence of Molecular Weight, Architecture, and Chemical Composition
Cigana, P.; Favis, B. D.; Jérôme, Robert ULg

in Journal of Polymer Science. Part B, Polymer Physics (1996), 34(9), 1691-1700

Interfacial agents used in the compatibilization of immiscible polymer blends often consist of block copolymers containing at least one segment compatible with each of the two phases of the blend. This ... [more ▼]

Interfacial agents used in the compatibilization of immiscible polymer blends often consist of block copolymers containing at least one segment compatible with each of the two phases of the blend. This work examines the influence of the molecular weight, architecture, and chemical composition of the interfacial agent on its ability to emulsify a polymer blend. The system chosen is a blend containing 80% polystyrene and 20% ethylene-propylene rubber, compatibilized by diblock copolymers of poly(styrene-hydrogenated butadiene). The emulsification curve, which relates the dispersed phase particle size to the concentration of interfacial agent added to the system, was used as a tool to characterize the efficacy of the different interfacial agents. The observed behavior is similar to that of classical emulsions: a rapid drop in phase size at low concentrations of interfacial modifier, followed by a levelling off to an equilibrium diameter value once a critical concentration has been reached. For systems compatibilized by symmetrical diblocks (i.e., containing approximately 50% styrene by weight), the volume average particle diameter decreased from 2.7 m for the unmodified system to about 0.4 m once interfacial saturation is reached. The critical concentration for emulsification decreased with increasing interfacial agent molecular weight, due to the higher interfacial area occupied by longer molecules; however, this parameter did not affect the equilibrium particle diameter. The asymmetrical diblock copolymer (30% styrene) was found to be less effective than the symmetrical ones over the entire range of concentrations studied (5 to 35% modifier, based on the volume of the minor phase). Asymmetrical diblock copolymers would tend to form micelles, whereas symmetrical copolymers are less constrained at the interface. No significant difference was observed between the emulsifying capability of tapered and pure diblocks of similar composition and molecular weight. [less ▲]

Detailed reference viewed: 28 (1 ULg)
See detailEthnic Politicians in Belgium
Martiniello, Marco ULg

Scientific conference (1996, July 03)

See detailBuckling of Hot-Rolled H-Section Columns at Elevated Temperature
Franssen, Jean-Marc ULg

Scientific conference (1996, July 02)

Detailed reference viewed: 15 (5 ULg)
Full Text
See detailTheorie laserinduzierter Rekombinationsprozesse
Schlagheck, Peter ULg

Master's dissertation (1996)

Detailed reference viewed: 27 (11 ULg)
Full Text
Peer Reviewed
See detailThe electroreduction of acrylonitrile : a new insight into the mechanism
Mertens, Marc; Calberg, Cédric ULg; Martinot, Lucien et al

in Macromolecules (1996), 29(14), 4910-4918

Several complementary electrochemical techniques have been used in order to clear up the mechanism of the electrochemical reduction of acrylonitrile (AN) on nickel. According to Lecayon et al., the ... [more ▼]

Several complementary electrochemical techniques have been used in order to clear up the mechanism of the electrochemical reduction of acrylonitrile (AN) on nickel. According to Lecayon et al., the electropolymerization of AN occurs in acetonitrile in the presence of tetraethylammonium perchlorate in such a way that polyacrylonitrile (PAN) is “grafted” onto the cathode. This electrochemical reaction has been reinvestigated both in acetonitrile, a nonsolvent of PAN, and in N,N-dimethylformamide (DMF), a good solvent for the polymer. The key role of the reduction potential on the electrografting reaction has been emphasized. The two electrochemical phenomena previously reported by Lecayon et al. have indeed been confirmed, but now it is clear that the “electrografting” of PAN selectively occurs at the less cathodic potential. At this potential, a PAN film is formed by a radical process and firmly secured onto the electrode, even in DMF. If the cathodic potential is further increased, the PAN film is easily removed from the metal and dissolves quickly in DMF. The transfer of one electron from the metal to the monomer occurs when the reduction is carried out at the more cathodic potential. A nonadherent PAN film is then formed onto Ni in acetonitrile, although the AN polymerization occurs in solution when acetonitrile is replaced by DMF. The AN polymerization is then consistent with an anionic process. [less ▲]

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailA Strategy for Multiple Immunophenotyping by Image Cytometry: Model Studies Using Latex Microbeads Labeled with Seven Streptavidin-Bound Fluorochromes
Gothot, André ULg; Grosdent, J. C.; Paulus, Jean-Michel ULg

in Cytometry (1996), 24(3), 214-25

Multiple immunophenotyping is aimed at identifying several cell populations in a single labeling procedure by their ability to bind combinations of specific labeled antibodies. The present work ... [more ▼]

Multiple immunophenotyping is aimed at identifying several cell populations in a single labeling procedure by their ability to bind combinations of specific labeled antibodies. The present work demonstrates the simultaneous discrimination by using image cytometry of aminomethylcoumarin acetate (AMCA), Lucifer yellow (LY), fluorescein isothiocyanate (FITC), R-phycoerythrin (PE), PE-Texas red tandem (Red613), peridinin-chlorophyll protein (PerCP), and allophycocyanin (APC), which were all bound to latex beads as streptavidin-conjugated fluorochromes. This has been the result of a step-by-step optimization of the several factors affecting the sensitivity and specificity of multiple immunofluorescence analysis. First, 14 streptavidin-conjugated fluorochromes were evaluated by using spectrofluorometry. A primary selection was then made of ten spectrally separable dyes that could be evaluated by using image cytometry. These dyes were bound to latex particles, and specific filter combinations were assembled to minimize crosstalk between fluorophores while preserving sufficient fluorescence intensity and counting statistics. Potential probe associations were then assessed by measuring the emissions of all fluorochromes that were detected by each filter combination. The resulting crosstalk matrix served as the basic tool both for final selection of the optimal filter combination and for dye set (composed, in this case, of the seven fluorochromes described above) and for mathematical correction of residual spectral overlap. Next, an image cytometry system was adapted to collect seven images of matched brightness with the selected combination of excitation/emission filters and dichroic mirrors. Finally, seven-parameter synthetic images were generated by digital image processing. [less ▲]

Detailed reference viewed: 26 (1 ULg)
Full Text
Peer Reviewed
See detailDistributive Justice and Social Equity: Québécois and French Students' Perceptions
Hudon, Raymond; Fournier, Bernard ULg

Conference (1996, July)

Detailed reference viewed: 11 (0 ULg)
Peer Reviewed
See detailIGF-I and IGFBPs in plasma of growing Landrace and large withe pigs.
Messina, M.; Prandi, A.; Nicolas, Nathalie et al

in Proceedings of the 14th IPVS Congress (1996, July)

Detailed reference viewed: 2 (0 ULg)
Peer Reviewed
See detailTAQ1 restriction fragment length polymorphism for pig growth hormone in pigs.
Nicolas, Nathalie; Fumiere, Olivier; Prandi, A. et al

in Proceedings of the 14th IVPS Congress (1996, July)

Detailed reference viewed: 134 (1 ULg)
Full Text
Peer Reviewed
See detailSimulation-based analysis of the renewal of a passive solar commercial building
Andre, Philippe ULg; Nicolas, Jacques ULg

in Proceedings PLEA 96 International conference (1996, July)

Detailed reference viewed: 3 (0 ULg)