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2,048 results on '"Legrand J."'

5. Comparative evaluation of freeze-dried and hot air-dried Spirulina Platensisextracts as green inhibitors for mild steel corrosion

Author

Seghiri, R., Rbaa, M., Rouifi, Z., Moussaif, A., Berdimurodov, E., Demir, M., Aliev, N., and Legrand, J.

Abstract

ABSTRACTSpirulina, a commercially farmed cyanobacteria, offers potential as a nontoxic corrosion inhibitor. However, traditional drying methods deteriorate its protective feature and this challenge must be overcome to enhance corrosive resistance. The present study compares the corrosive inhibitor performance of Spirulina extracts from freeze (SP1) and hot air drying (SP2). The electrochemical and microscopic techniques revealed that freeze-dried-derived Spirulina inhibited over 90% of corrosion through the chemisorption process where freeze-dried-derived Spirulina maximises the inhibitory compounds binding to steel. Polarisation measurements showed that SP1 provided higher inhibition efficiencies of over 93% at certain concentrations compared to around 88% for SP2. At the optimal concentration of 2 g/L, Rp values increased from 35.17 Ω/cm2(uninhibited) to 531.3 Ω/cm2for SP1 and 282.7 Ω/cm2for SP2. Negative ΔGadsvalues (−42.4 kJ/mol for SP2, −46.3 kJ/mol for SP1) and Langmuir isotherm fit indicated chemisorption-controlled adsorption. SEM/EDX showed SP1 and SP2 formed barrier layers inhibiting surface damage compared to blank steel. SP1 layer provided better protection. In short, through innovative applications of marine resources, greener corrosion management is enabled.

Published
2024
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16. Investigating liquid surfaces down to the nanometer scale using grazing incidence x-ray scattering

Author

Fradin, C., Braslau, A., Luzet, D., Alba, M., Gourier, C., Daillant, J., Gruebel, G., Vignaud, G., Legrand, J. -F., Petit, J. Lal J. -M., and Rieutord, F.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Grazing incidence x-ray surface scattering has been used to investigate liquid surfaces down to the molecular scale. The free surface of water is well described by the capillary wave model ( ~ q-2 spectrum) up to wavevectors > 10^8 m^-1. At larger wavevectors near-surface acoustic waves must be taken into account. When the interface is bounded by a surfactant monolayer, it exhibits a bending stiffness and the bending rigidity modulus can be measured. However, bending effects generally cannot be described using the Helfrich Hamiltonian and the characteristic exponent in the roughness power spectrum can smaller than 4. Finally, upon compression, tethered monolayers formed on a subphase containing divalent ions are shown to buckle in the third dimension with a characteristic wavelength on the order of 10^8 m^-1.

Published
1997
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25. Regional integration of long-term national dense GNSS network solutions

Author

Kenyeres, Ambrus, Bellet, J. G., Bruyninx, C., Caporali, A., de Doncker, F., Droscak, B., Duret, A., Franke, P., Georgiev, I., Bingley, R., Huisman, L., Jivall, L., Khoda, O., Kollo, K., Kurt, A. I., Lahtinen, S., Legrand, J., Magyar, B., Mesmaker, D., Morozova, K., Nágl, J., Özdemir, S., Papanikolaou, X., Parseliunas, E., Stangl, G., Ryczywolski, M., Tangen, O. B., Valdes, M., Zurutuza, J., and Weber, M.

Published
2019
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26. Demokratische Öffentlichkeit – eine medienpolitische Gestaltungsaufgabe

Author

Legrand, Jupp, Linden, Benedikt, Arlt, Hans-Jürgen, Legrand, J ( Jupp ), Linden, B ( Benedikt ), Arlt, H ( Hans-Jürgen ), Jarren, Otfried, Fischer, Renate; https://orcid.org/0000-0003-0584-2349, Legrand, Jupp, Linden, Benedikt, Arlt, Hans-Jürgen, Legrand, J ( Jupp ), Linden, B ( Benedikt ), Arlt, H ( Hans-Jürgen ), Jarren, Otfried, and Fischer, Renate; https://orcid.org/0000-0003-0584-2349

Abstract

Der aktuelle Medienwandel verändert die Struktur der Öffentlichkeit und beeinflusst dadurch auch politische Prozesse, die für die Konstitution der Demokratie relevant sind. Treibende Kraft des Wandels ist der erfolgreiche Zutritt global agierender privater Plattformen in den Medienmarkt. Ausgehend von der These der Gestaltungsbedürftigkeit von Öffentlichkeit systematisiert der Beitrag demokratische Gewinne und Gefährdungen des plattformisierten Mediensystems: Die Artikulationsmöglichkeiten aller steigen, während die Chancen zur nachvollziehbaren Kontextualisierung, Aggregation und Bewertung von Interessenanmeldungen abnehmen und der Gesamtinklusionsgrad der Öffentlichkeit sinkt. Die zukünftige Medienordnung wird daher zu einer demokratiepolitischen Aufgabe ersten Ranges. Sie muss den funktionalen Besonderheiten, Stärken und Schwächen der jeweiligen Medien, allen voran der Plattformen, Rechnung tragen und das Gesamtsystem der Medien bezogen auf seinen Beitrag zu einer vielfältigen und auf Inklusion angelegten Öffentlichkeit regulieren.

Published
2023

32. IAG WG SC1.3 on Regional Dense Velocity Fields: First Results and Steps Ahead

Author

Bruyninx, C., Legrand, J., Altamimi, Z., Becker, M., Craymer, M., Combrinck, L., Combrink, A., Dawson, J., Dietrich, R., Fernandes, R., Govind, R., Griffiths, J., Herring, T., Kenyeres, A., King, R., Kreemer, C., Lavallée, D., Sánchez, L., Sella, G., Shen, Z., Santamaría-Gómez, A., Wöppelmann, G., Altamimi, Zuheir, editor, and Collilieux, Xavier, editor

Published
2013
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33. A Dense Global Velocity Field Based on GNSS Observations: Preliminary Results

Author

Bruyninx, C., Altamimi, Z., Becker, M., Craymer, M., Combrinck, L., Combrink, A., Dawson, J., Dietrich, R., Fernandes, R., Govind, R., Herring, T., Kenyeres, A., King, R., Kreemer, C., Lavallée, D., Legrand, J., Sánchez, L., Sella, G., Shen, Z., Santamaría-Gómez, A., Wöppelmann, G., Kenyon, Steve, editor, Pacino, Maria Christina, editor, and Marti, Urs, editor

Published
2012
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35. The IAG combined global GNSS velocity field (JWG 3.2)

Author

Santamaria, A., Rietbroek, R., Frederikse, T., Rebischung, P., and Legrand, J.

Abstract

Estimates of GNSS velocities are significantly impacted by the choices made concerning the GNSS data processing (corrections applied and noise level of the series), the completeness of the series and the alignment to a reference frame. In particular, position discontinuities, that populate the GNSS time series, have probably the biggest impact on the velocity error. All these effects may produce, at least, an increased velocity uncertainty, but it may also lead to biased velocity estimates. The result is that GNSS velocities estimated by different analysts can significantly differ from each other, even when using exactly the same position series.The objective of the IAG Joint Working Group 3.2 is to provide a combined global GNSS velocity field that takes into account the dispersion of the different velocity estimates at the same sites provided by different groups together with their alignment and their relative weighting. We expect that this IAG combined GNSS velocity field will be useful for the scientific community inside, but especially outside, the geodetic community in areas such as tectonics, sea-level change and GIA modeling among others. In this contribution, we present the latest global combined velocity field based on the available global and regional velocity fields provided by several groups, and show the level of agreement between the velocity fields., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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37. Surface Methods

Author

Altschuh, D., Ricard-Blum, S., Ball, V., Gaillet, M., Schaaf, P., Senger, B., Desbat, B., Lavalle, P., Legrand, J.-F., Boisseau, Patrick, editor, Houdy, Philippe, editor, and Lahmani, Marcel, editor

Published
2009
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