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Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Ecology, Ecologie, Geology, Géologie, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Sciences de la terre, Earth sciences, Géochimie, Geochemistry, Géochimie des sols et des roches, Soil and rock geochemistry, Formations superficielles, Surficial geology, Quaternaire marin et continental, Marine and continental quaternary, Europe, Europa, Actuel, modern, Actual, Calcium, calcium, Calcio, Carbohydrate, carbohydrates, Matière particulaire, particulate matters, Partícula elemental, Milieu intertidal, intertidal environment, Medio intertidal, Particule, particles, Rhéologie, rheology, Reología, Sorption, sorption, Sorción, Stabilisation, stabilization, Estabilización, Sédimentation estuaire, estuarine sedimentation, Sedimentación estuario, Vasière, mud flats, and Marisma

Extracellular Polymeric Substances (EPS) are considered to play an important role in the stabilization of intertidal mudflats. In this study the role of EPS as a binding agent in intertidal sediments was investigated. For this purpose two EPS fractions (termed coll-SF and EDTA-SF) were isolated from intertidal sediment and characterized in terms of monosaccharide- and size distribution. In slurry addition experiments the sorption characteristics of these EPS-fractions as well as their effect on sediment properties were examined under varying Ca2+-concentrations. Results showed more EDTA-SF adsorbed to the sediment compared to coll-SF. For both fractions more EPS adsorbed to the sediment when Ca2+-concentration increased. This effect was stronger for EDTA-SF. The differences in sorption between the two fractions could not be explained in terms of monosaccharide- and size distribution, which were largely similar. The addition of EPS in the presence or absence of Ca2+ did not alter the rheology of the sediment slurries indicating that there was no effect of EPS on the sediment properties. This contradicts results of experiments with bacterial EPS as well as field observations in which the presence of EPS/ biofilms leads to an increase in the erosion resistance of the sediment. Possible causes for this discrepancy in results are discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Structure et morphologie; épaisseur, Structure and morphology; thickness, Diffraction RX, XRD, Dépôt physique phase vapeur, Physical vapor deposition, Etude expérimentale, Experimental study, Frottement, Friction, Magnétron, Magnetrons, Microscopie électronique balayage, Scanning electron microscopy, Microstructure, Molybdène sulfure, Molybdenum sulfides, Propriété mécanique, Mechanical properties, Pulvérisation irradiation, Sputtering, Revêtement, Coatings, Tribologie, Tribology, Usure, and Wear

MoSx coatings were prepared with an unbalanced DC magnetron-sputtering system by varying the DC power mode, target type and liquid nitrogen trap. The composition and surface morphology were examined by energy dispersive X-ray and scanning electron microscopy; structural characterization was determined by X-ray diffraction. The friction and wear properties were evaluated with a fretting tester in dry (< 10% relative humidity) and humid (50% and 90% relative humidity) air. MoSx coatings deposited by simple DC power tended to form rougher surfaces, and had a higher edge orientation of crystallites with worse tribological performance than those by bipolar pulsed DC power. MoSx coatings made by a cold pressed target had a lower deposition rate, and were inclined to form (002) basal orientations parallel to the surface especially at higher argon pressures. The contents of oxygen and carbon in the MoSx coating with the use of liquid nitrogen trap were greatly reduced, but MoSx coatings had lower coefficients of friction and shorter wear life at higher relative humidity. The role of these deposition variables in the formation process is discussed.

Electronics, Electronique, Condensed state physics, Physique de l'état condensé, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Dispositifs optoélectroniques, Optoelectronic devices, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Domaines d'application, Application fields, Caractéristique temporelle, Time curve, Característica temporal, Caractéristique électrique, Electrical characteristic, Característica eléctrica, Diode électroluminescente, Light emitting diode, Diodo electroluminescente, Effet champ électrique, Electric field effect, Efecto campo eléctrico, Electroluminescence, Electroluminiscencia, Etude expérimentale, Experimental study, Estudio experimental, Mécanisme, Mechanism, Mecanismo, Phénylènevinylène polymère, Phenylenevinylene polymer, Fenilenovinileno polímero, Polymère conjugué, Conjugated polymer, Polímero conjugado, Vieillissement, Ageing, and Envejecimiento

Polymer light-emitting diodes (PLEDs) made with poly(p-phenylene vinylene) (PPV) using a non-ionic precursor route with indium-tin oxide (ITO) as anode and Al as cathode have been examined during continuous electrical stress in an oxygen-rich atmosphere. Three distinct regions in the time evolution of the equivalent electrical resistance and the light output of PLEDs are identified. Various electrical and analytical measurement results are presented to explain the main failure mechanisms. The most severe degradation mode can be identified as dielectric breakdown, resulting in 'hot spots' and ohmic leakage paths. The inhibition of the ohmic path formation by oxidation under ambient conditions results in a local delamination of the electrode, shrinking the active area of the device. This loss of active area caused by these oxidative burn-outs can clearly be observed by scanning electron microscopy ( SEM) and is consistent with secondary ion mass spectroscopy (SIMS) results. Emission microscopy (EMMI) inspection provides evidence for electric field induced ageing at defects present in the device. These defects are already present in the as-produced samples, e.g. particle impurities, interface roughness and structural weakness (edges of the Al electrodes).

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Propriétés physiques non électroniques de couches minces, Physical properties of thin films, nonelectronic, Propriétés mécaniques et acoustiques, Mechanical and acoustical properties, Coefficient frottement, Friction factor, Dépôt physique phase vapeur, Physical vapor deposition, Essai usure, Wear testing, Etude expérimentale, Experimental study, Magnétron, Magnetrons, Microstructure, Molybdène sulfure, Molybdenum sulfides, Propriété mécanique, Mechanical properties, Propriété surface, Surface properties, Revêtement, Coatings, SEM, Tribologie, Tribology, Usure petit débattement, Fretting wear, Desgate pequinio desplazamiento, Usure, and Wear

MoSx coatings were prepared by bipolar pulse DC (balanced and unbalanced) magnetron-sputtering systems. Deposition parameters, cathode current density, argon pressure, bias voltage and magnetron sputtering conditions, were varied in order to obtain low friction and wear-resistant coatings. Composition and surface morphology were determined by energy dispersive X-rays and scanning electron microscopy, while the structure was investigated by X-ray diffraction. The friction and wear properties were investigated by fretting tests in ambient air of < 10% and 50% relative humidity. On proper selection of the argon pressure and the cathode current density, MoSx coatings characterised by a strong (002) basal plane orientation parallel to the substrate were obtained in a reproducible way. Such coatings deposited under optimised conditions exhibit very good lubricity and high wear-resistance, even in ambient air with a relative humidity of 50%. Conversely, when deposition parameters such as higher argon pressure and larger cathode current density result in the deposition of a MoSx coatings with a needle-like structure and preferential (100) and (110) plane orientations, a lower wear resistance is achieved especially in air of 50% relative humidity. Ion bombardment, achieved by applying a negative voltage bias or unbalanced sputtering conditions, improves the friction and wear performance. Conversely, a positive bias voltage deteriorates the tribological performance of the coatings. Experimental data on the friction and sliding wear resistance for MoSx coatings indicate that the best tribological properties are obtained with low sulfur and featureless MoSx coatings.

Marine biology, limnology, Biologie marine, limnologie, Ecology, Ecologie, Environment, Environnement, Oceanography, Océanographie, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Sciences de la terre, Earth sciences, Formations superficielles, Surficial geology, Quaternaire marin et continental, Marine and continental quaternary, Europe, Europa, Océan Atlantique, Atlantic Ocean, Océano Atlántico, Procaryote, prokaryotes, Bactérie, bacteria, Carbone organique, organic carbon, Carbono orgánico, Effet biogène, biogenic effects, Effet tampon, buffer effects, Efecto tampón, Fer, iron, Hierro, Milieu littoral, coastal environment, Medio litoral, Oxydation, oxidation, Oxidación, Porosité, porosity, Porosidad, Réduction chimique, chemical reduction, Reducción química, Sulfate, sulfates, Sulfato, Sulfure, sulfides, Sulfuro, Sédiment marin, marine sediments, Sedimento marino, Variation verticale, and vertical variations

The Bassin d'Arcachon (south-west France) was chosen as a model ecosystem to study the chemical and microbiological buffering towards free sulphide. Data were collected on the vertical distribution of oxygen, sulphur and iron compounds and the vertical distribution of colourless sulphur bacteria and sulphide-producing bacteria. In addition, data on the chemical and biological buffering capacity towards free sulphide were collected in sediment slurries from defined depth layers using a biological sulphide and oxygen monitor (BOSM) equipped with electrodes for oxygen, sulphide, redox and pH. The data showed that a substantial population of aerobic sulphide-oxidizing bacteria was present, yet buffering towards free sulphide could mainly be attributed to chemical processes: in particular, reactions with iron were of importance. Interestingly, the potential microbiological rate of sulphide oxidation was orders of magnitude higher than the rate of sulphate reduction reported for this ecosystem. The ecological implications of these observations for the Bassin d'Arcachon are that the powerful biological buffering capacity towards the free sulphide present will become effective after the chemical buffering capacity has been depleted. Under such conditions the colourless sulphur bacteria will no longer face the competition with iron, and thus may be expected to proliferate. The crucial factor then becomes the availability of oxygen.

Control theory, operational research, Automatique, recherche opérationnelle, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Essais, mesure, bruit et fiabilité, Testing, measurement, noise and reliability, Diélectrique, Dielectric materials, Dieléctrico, Essai en place, In situ test, Ensayo en sitio, Essai vieillissement accéléré, Accelerated aging test, Ensayo envejecimiento acelerado, Fiabilité, Reliability, Fiabilidad, Mesure, Measurement, Medida, Métallisation, Metallizing, Metalización, Optimisation, Optimization, Optimización, Résistance électrique, Resistor, and Resistencia eléctrica(componente)

Electronics, Electronique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Circuits intégrés, Integrated circuits, Conception. Technologies. Analyse fonctionnement. Essais, Design. Technologies. Operation analysis. Testing, Aluminium, Aluminio, Circuit intégré, Integrated circuit, Circuito integrado, Electrodiffusion, Electrodifusión, Encapsulation, Encapsulación, Etude expérimentale, Experimental study, Estudio experimental, Fiabilité, Reliability, Fiabilidad, Interconnexion, Interconnection, Interconección, Métallisation, Metallizing, Metalización, Or, Gold, Oro, Phénomène transport, Transport process, and Fenómeno transporte

Control theory, operational research, Automatique, recherche opérationnelle, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Circuits intégrés, Integrated circuits, Conception. Technologies. Analyse fonctionnement. Essais, Design. Technologies. Operation analysis. Testing, Aluminium, Bille, Caractéristique temporelle, Circuit intégré, Contact métal métal, Contrainte thermique, Electrodiffusion, Essai vieillissement accéléré, In situ, Interconnexion, Mesure, Or, and Résistance contact

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Propriétés et caractérisation, Properties and characterization, Propriétés des solutions et des gels, Solution and gel properties, Activité catalytique, Catalyst activity, Actividad catalítica, Agrégation moléculaire, Molecular aggregation, Agregación molecular, Aldolisation, Aldol condensation, Aldolización, Aminoacide, Aminoacid, Aminoácido, Catalyse asymétrique, Asymmetric catalysis, Catálisis asimétrica, Composé chiral, Chiral compound, Compuesto quiral, Composé marqué, Labelled compound, Compuesto marcado, Copolymère greffé, Graft copolymer, Copolímero injertado, Cyclanone, Cycloalkanone, Ciclanona, Dérivé du benzaldéhyde, Benzaldehyde derivatives, Benzaldehído derivado, Enantiosélectivité, Enantioselectivity, Enantioselectividad, Ethylène oxyde copolymère, Ethylene oxide copolymer, Etileno óxido copolímero, Etude expérimentale, Experimental study, Estudio experimental, Marqueur fluorescent, Fluorescent tracer, Marcador fluorescente, Méthacrylate copolymère, Methacrylate copolymer, Metacrilato copolímero, Nanoencapsulation, Nanoencapsulación, Nanoparticule, Nanoparticle, Nanopartícula, Polymère amphiphile, Amphiphilic polymer, Polímero amfifilo, Reconnaissance moléculaire, Molecular recognition, Reconocimiento molecular, Solution aqueuse, Aqueous solution, Solución acuosa, Spectre dichroïsme circulaire, Circular dichroism spectrum, Espectro dicroismo circular, Dérivé de la proline, Particule monomoléculaire, aldol reaction, benzene-1,3,5-tricaboxamide, molecular recognition, organocatalysis, and single-chain polymeric nanoparticles

Here, a modular approach is reported to introduce a specific function into single-chain polymeric nanoparticles (SCPNs). Hereto, an amphiphilic polymer with pendant benzene-1,3,5-tri-carboxamide (BTA) units is mixed with a free BTA that contains a functional group, either a fluorescent naphthalimide or a catalytically active L-proline. Taking advantage of hydrophobic interactions and self-recognition properties of the BTA units, the free BTAs are captured into the interior of the SCPN in water as evidenced by fluorescence studies. To illustrate that function can be readily introduced using a modular approach, L-proline-based BTAs are incorporated to procure a catalytically active SCPN in water. The aldol reaction between p-nitrobenzaldehyde and cyclohexanone shows good conversions at low catalyst loadings and substrate concentrations, and high stereoselectivities are obtained (de = 91% and ee = 98%).

Energy, Énergie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Installations de production et de conversion d'énergie: énergie électrique, énergie thermique., Installations for energy generation and conversion: thermal and electrical energy., Centrales nucléaires à fission, Fission nuclear power plants, America, South America, Amérique du Sud, Amérique, America del sur, Analyse, Analysis, Arbre événement, Brésil, Brazil, Brasil, Centrale nucléaire, Nuclear power plant, Planta nuclear, Evaluation probabiliste, Programme ordinateur, Computer program, Risque, Risk, Riesgo, Sécurité, Safety, and Securidad

Description de la méthodologie utilisée dans le programme d'ordinateur d'analyse d'arbres d'événements pour des évaluations probabilistes de risques. Description détaillée de la structure du programme et de ses entrées et sorties. Discussion de quelques limitations de la version actuelle du programme.

Crystallography, Cristallographie cristallogenèse, Electronics, Electronique, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Propriétés physiques non électroniques de couches minces, Physical properties of thin films, nonelectronic, Propriétés mécaniques et acoustiques, Mechanical and acoustical properties, Contrainte compression, Compressive stress, Tensión compresión, Contrainte résiduelle, Residual stresses, Contrainte traction, Tensile stress, Tensión traccíon, Densité énergie, Energy density, Dépôt physique phase vapeur, Physical vapor deposition, Etude théorique, Theoretical study, Faisceau ion, Ion beams, Film, Films, Modèle, Models, Modelo, Propriété mécanique, Mechanical properties, Relation fabrication propriété, Fabrication property relation, Relación fabricación propiedad, Revêtement, and Coatings

A relative simple model is elaborated for the overall behaviour of the residual stress in a coating layer, grown under continuous bombarding of energetic particles. It concentrates on the transition from tensile to compressive stress under increasing energetic particle flux, a phenomenon frequently observed in experiments. The energy density E in the film is written as a sum of an elastic deformation contribution, and a contribution due to depletion zones between the growing columns. Minimization of E leads to the value of the lateral stress in the film. It is found that the film stress shows a characteristic behaviour on the ratio Jion/Jat (ion to atom flux ratio). Generally, for increasing Jion/Jat the stress will first attain a maximum tensile value, and then will change from tensile to compressive values. Further we find that the maximum tensile stress and the tensile/compressive transition occur at lower Jion/Jat ratios for higher energies of the incoming energetic particles. These findings agree with a number of experimental results.

Mechanical engineering, Génie mécanique, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Essais sur les matériaux, Materials testing, Sciences appliquees, Applied sciences, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Métrologie industrielle. Contrôle, Industrial metrology. Testing, Contrôle non destructif: méthodes et appareillages, Non-destructive testing: methods and equipments, Acier électrique, Electric furnace steel, Acero horno eléctrico, Conversion onde, Wave conversion, Conversión onda, Dispositif électromagnétique, Electromagnetic devices, Effet Barkhausen, Barkhausen effect, Effet champ magnétique, Magnetic field effects, En ligne, On line, En línea, Essai courant Foucault, Eddy current testing, Essai non destructif, Nondestructive testing, Essai perte magnétique, Magnetic leakage field testing, Control pérdida magnética, Fer, Iron, Grosseur grain, Grain size, Joint grain, Grain boundaries, Mesure électrique, Electrical measurement, Medida eléctrica, Métrologie, Metrology, Processus fabrication, Production process, Proceso fabricación, Procédé fabrication, Manufacturing processes, Visualisation, and Visualization

The results of investigation of the relation between the grain size in the intermediate stages of manufacturing electrical steel and various physical characteristics are given. The investigations are carried out for the purpose of clarifying the possibility of using these characteristics for arranging nondestructive testing of the grain size in the process of steel manufacturing. The paper contains the results of tests performed with the use of the methods of measuring the leakage magnetic fields on the grain boundaries by means of yttrium iron garnet films employed for visualization of the magnetic fields, the Barkhausen effect, the ultrasonic and eddy-current methods, the electromagnetic-acoustic conversion (EMAC) method, and the use of the relation between the grain size and the value of the coercive force.