Статті в журналах: "Feux de surfaces"

1

KONKO, Yawo, Bareremna AFELU, and Kouami KOKOU. "Potentialité des données satellitaires Sentinel-2 pour la cartographie de l’impact des feux de végétation en Afrique tropicale : application au Togo." BOIS & FORETS DES TROPIQUES 347 (March 31, 2021): 59–73. http://dx.doi.org/10.19182/bft2021.347.a36349.

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Le réchauffement climatique est un phénomène d’envergure mondiale qui se répercute sur le système climatique. Une des conséquences du réchauffement climatique est l'extension de la période de sécheresse, favorisant ainsi l’augmentation des fréquences du phénomène des feux de végétation. Les feux incontrôlés perturbent l’écologie et la fonctionnalité des écosystèmes, entraînant parfois leur érosion. La présente étude est une contribution pour la gestion des feux de végétation au Togo et porte sur le suivi spatial pour la saison des feux 2018-2019. Elle explore la potentialité des nouvelles données satellitaires Sentinel-2 (S-2) en accès libre dans la gamme de la télédétection optique pour la détection des surfaces brûlées, la cartographie des feux utilitaires et des feux incontrôlés. Elle teste également la performance de la méthode de cartographie des feux de végétation à partir de l’indice NBR (Normalized Burn Ratio) initialement conçue pour les images Landsat et évalue la biomasse végétale brûlée. Les résultats révèlent que les images S-2 présentent du potentiel dans la restitution des surfaces brûlées. La performance de la méthode de l’indice NBR sur les images S-2 est satisfaisante. La cartographie des feux de végétation montre que les feux utilitaires représentent 21,75 % contre 78,25 % pour les feux incontrôlés. L’ensemble des feux de végétation enregistrés a occasionné l’incendie de 5 878 km2 du couvert végétal, soit 10,39 % du territoire national. Le couvert végétal brûlé est composé majoritairement de savanes (33,12 %), de cultures et jachères (24,48 %), de plantations (14,59 %), de forêts claires (14,43 %) et de forêts riveraines (13,02 %). Les résultats obtenus constituent des éléments tangibles pour le suivi, la sensibilisation, l’élaboration des plans d’aménagement, de prévention et de gestion des feux.

2

Rossi, Lucile. "Développement de systèmes de mesure basés sur la Stéréovision dédiés aux feux en propagation." Revue Française de Photogrammétrie et de Télédétection, no. 201 (April 16, 2014): 2–12. http://dx.doi.org/10.52638/rfpt.2013.41.

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Les feux de forêt représentent un risque majeur pour de nombreux pays dans le monde. Pour lutter contre ce danger, des actions de gestion, de prévention et de lutte sont réalisées. L'efficacité de ces trois types d'action est liée à la connaissance des phénomènes qui interviennent lors de la propagation des feux et à l'amélioration des modèles de comportement. Les feux sont caractérisés par l'évolution temporelle de leur position, vitesse, hauteur, surface et volume. Il est donc nécessaire de développer des systèmes permettant la mesure de ces caractéristiques géométriques. Depuis une dizaine d'années, des travaux utilisant le traitement d'image et la vision ont été menés pour obtenir des données estimées sur des feux expérimentaux. Trois familles de systèmes sont apparues : la première est dédiée aux feux se propageant en laboratoire. Elle utilise des informations 2D et ne permet l'estimation que d'un nombre restreint de caractéristiques. La deuxième est dédiée aux feux se propageant à l'extérieur sur de grands terrains de pente uniforme aménagés. Elle utilise des méthodes de traitement d'images et de vision et permet l'obtention d'un modèle de perception 3D du feu à partir d'information 2D. Ces méthodes nécessitent le positionnement sur le terrain de repères de position et de hauteur et sont difficilement transposables sur différentes configurations de terrain ; d'autre part, elles ne permettent pas l'estimation de la surface et du volume d'un feu. Une troisième famille de systèmes utilise la stéréovision pour obtenir un ensemble de points tridimensionnels de feu à partir desquels les caractéristiques géométriques des feux sont estimées. Cet article présente les travaux de recherche menés par l'auteur qui est à l'origine de la troisième famille de systèmes de mesure dédiés aux feux en propagation.

3

Faerber, Johanna. "De l'incendie destructeur à une gestion raisonnée de l'environnement : le rôle du feu dans les dynamiques paysagères dans les Pyrénées centrales françaises." Sud-Ouest européen 7, no. 1 (2000): 69–79. http://dx.doi.org/10.3406/rgpso.2000.2730.

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Dans les Pyrénées centrales, la déprise agricole a profondément modifié l'entretien traditionnel des pâturages par le feu. Soumis à une réglementation lourde, les brûlages ont dérivé dans la clandestinité. Leur nombre a diminué, mais la surface totale brûlée a fortement augmenté. Les conséquences paysagères des feux se sont diversifiées : dans les zones de parcours de mi-saison, le feu maintient le cortège floristique des landes et garantit à long terme leur pérennité, empêchant leur transformation en bois. Dans les forêts en soulane, les feux entraînent une altération progressive pour les hêtraies, et des destructions en surface pour les chênaies. Apparue depuis quelques années, une innovante politique du brûlage dirigé porte aujourd'hui ses premiers fruits : maintien voire restauration d'une technique efficace de conservation des paysages, baisse réelle des feux non contrôlés et diminution des dégradations des forêts en soulane.

4

Godmaire, Anne, and Serge Payette. "Dynamique spatio-temporelle d’une bande forestière près de la limite des forêts, rivière aux Feuilles, Nouveau-Québec." Géographie physique et Quaternaire 35, no. 1 (January 25, 2011): 73–85. http://dx.doi.org/10.7202/1000379ar.

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La répartition spatiale des individus vivants et morts des populations de mélèzes (Larix laricina (DuRoi) K. Koch) et d’épinettes noires (Picea mariana (Mill.) BSP.) d’une bande forestière a permis de préciser leur comportement depuis 1550 ans BP. L’influence des conditions climatiques et des feux sur ces populations forestières a pu être déterminée. La fluctuation du succès de régénération et celle de la répartition spatiale des individus des cinq dernières décennies sont attribuables aux conditions climatiques. Deux feux récents, il y a 100 ans et 160 ans, ont influencé en partie le patron de répartition ainsi que le succès de colonisation des individus plus âgés. Ces feux ont restreint les populations arborescentes à une dépression topographique humide en plus d’affecter la structure des populations. Les différents horizons de charbons de bois détectés sur le site (1550 ± 130 ans BP, 1170 ± 100 ans BP, 640 ± 80 ans BP) ainsi que leur répartition indiquent que les feux ont exercé une influence sur l’importance du couvert forestier. Avant 1550 ans BP, la bande forestière occupait une surface plus grande qu’actuellement. Après le feu de 1170 ans BP, un changement dans la fréquence et le comportement des feux associé aux manifestations du pergélisol pendant cette période suggèrent un refroidissement climatique Finalement, les fluctuations spatiales des populations sont reliées aux changements du climat depuis 1550 ans BP, mis en évidence par l’absence ou le succès de la régénération après feu du mélèze et de l’épinette noire.

5

Millet, Jeanne, and Serge Payette. "Influence des feux sur la déforestation des îles centrales du lac à l’Eau Claire, Québec nordique." Géographie physique et Quaternaire 41, no. 1 (December 18, 2007): 79–86. http://dx.doi.org/10.7202/032666ar.

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RÉSUMÉ Les îles et le pourtour du lac à l'Eau Claire (56°15'N, 74°30'O) montrent d'importantes différences au niveau de la structure et de la superficie occupée par les formations conifériennes. D'une île à l'autre, le pourcentage de recouvrement réel des conifères et des arboraies varie respectivement entre 10 et 35 % et 3 et 35 %. Cette végétation contraste avec les lichénaies situées au sommet des collines, où l'on trouve sous le couvert végétal des charbons d'épinette noire (Picea mariana (Mill.) BSP.), vestiges de formations conifériennes autrefois plus étendues. Une analyse des datations au radiocarbone de charbons de bois révèle que les îles centrales du lac à l'Eau Claire subissent une deforestation depuis au moins 2350 BP. En conjonction avec le climat, les feux ont profondément influencé la dynamique spatio-temporelle des formations conifériennes. Les îles centrales du lac à l'Eau Claire ont toutes connu une histoire des feux différente et, par conséquent, une deforestation variable. Cinq périodes d'ouverture du paysage ont été identifiées, soit 2350-2100,1650-1450, 1350-1050, 850-650 et 400-200 BP. Par ailleurs, on évalue à environ 5 % des deux plus grandes îles (Atkinson et Lepage) la surface déboisée par les feux de 400 BP; de plus, un feu d'il y a environ 200 ans a détruit 4 % de la surface boisée de l'île Atkinson. On en conclut que la faible représentation des conifères dans certaines îles du lac à l'Eau Claire illustre leurs difficultés d'établissement après feu. À l'inverse, leur présence dans les sites exposés souligne leur capacité de maintien en l'absence de perturbation majeure.

6

Zhang, Pengze, Jingyu Yan, Fei Han, Xianliang Qiao, Qingxin Guan, and Wei Li. "Controllable assembly of Fe₃O₄–Fe₃C@MC by in situ doping of Mn for CO₂ selective hydrogenation to light olefins." Catalysis Science & Technology 12, no. 7 (2022): 2360–68. http://dx.doi.org/10.1039/d2cy00173j.

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Mn in situ doped Fe3C anchored in mesoporous carbon was prepared and employed for converting CO2 to light olefins successfully. The in situ doped Mn modified the ratio of FeOx/FeCx and surface electron density, which optimized the C/H on active sites.

7

Yedmel, Memel S. Ch, Adjumane A. Kadio, Olivier J. Hardy, N’Guessan François Kouame, and Nicolas S. Barbier. "Impact du feu sur la structure et la composition floristique d’un peuplement forestier de Côte d’Ivoire et interaction avec les traitements sylvicoles." Canadian Journal of Forest Research 40, no. 10 (October 2010): 1904–13. http://dx.doi.org/10.1139/x10-117.

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La dynamique structurale et floristique des forêts tropicales humides en réponse aux perturbations reste très méconnue, en dépit des problématiques actuelles de stockage de carbone et de conservation de la biodiversité. Le dispositif de la Téné (Côte d’Ivoire) est un peuplement forestier suivi depuis 1978, afin d’étudier à long terme la dynamique des espèces à potentiel commercial. En 1983, il a été accidentellement parcouru par le feu, et plus de 65 % de la surface totale a été atteinte. L’objectif de cette étude est d’évaluer l’impact des modalités sylvicoles combinées au passage du feu sur la structure et la composition floristique du peuplement. Les variations structurales et floristiques ont été testées respectivement à l’aide d’un simple modèle d’ANCOVA et d’une ordination. Les résultats obtenus montrent que l’impact du feu, en termes de surface brûlée, de structure et de composition floristique, a été significativement accru par les perturbations induites par les traitements sylvicoles. Les modalités sylvicoles supposées bénéfiques à l’accroissement des espèces à potentiel commercial peuvent accroître la susceptibilité aux feux et entraîner à long terme des effets majeurs sur la structure et la composition floristique du peuplement.

8

Oloukoi, J., I. Yabi, and D. Johnson. "Influence des Facteurs Climatiques et Topograpbiques . Sur Les Risques de Feux de Vegetation au Centre du Benin." Journal of Geospatial Science and Technology 1, no. 1 (November 1, 2014): 31–51. http://dx.doi.org/10.54222/afrigist/jgst/v1i1.3.

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This paper analyzes the relationship between climatic and topographic parameters and fire risks in the center of Benin, using climatic and topographic data and the. fire radiative power of fires hotspots acquired by MODIS sensor. Spatial inte1polation with the Natural Neighbor algorithm and the Pearson correlation has helped analyze the contribution of each parameter in the ignition and propagation of fire. The vegetation Drought Index which links the surface temperature and the ND VI through a linear regression has helped assess the fire risk. An increase in temperature, sunshine period, and wind speed augment the fire radiative power while the correlation is rather negative with the relative humidity. Altitude and slope influence also positively the fire radiative power. Out of these parameters, only temperature, sunshine period, and slope are significant at 0.05. The drought index indicates that considering the magnitude of the surface temperature, any point of the area where exists dry vegetation could be affected by the fire. Cet article analyse la relation entre /es parametres climatiques . et topographiques et /es risques de feu au centre du Benin utilisant /es donnees climatiques et topographiques et lepouvoir radiatif des points de feux acquis par le capteur de MODIS. L 'interpolation spatiale de ces donnees par l'algorithme du Voisin Nature/ et la correlation de Pearson ont permis de mesurer la contribution de chaque parametre dans l 'eclosion et la propagation du feu. L 'indice de secheresse de la vegetation qui lie la temperature de surface et le ND VI a travers une regression lineaire, apermis d ,apprecier /es risques defeu. Au total, la temperature, l'humidite relative, l'insolation et la vitesse du vent injluencent le pouvoir radiatif desfeux. La pente et / 'altitude injl.uencent aussi positivement la propagation des feux. Mais de tous ces parametres, seules la temperature, l 'insolation et la pente sont significatives au seuil de 0,05 de niveau alpha. L 'indice de secheresse de la vegetation indique que selon le niveau de la temperature de surface, tout point ou existe de la vegetation seche peut etre affecte par lefeu.

9

Pan, Yueshen, Xiaoxu Ding, Chao Zhang, Minghui Zhu, Zixu Yang та Yi-Fan Han. "Effects of Different Reductive Agents on Zn-Promoted Iron Oxide Phases in the CO2–Fischer–Tropsch to Linear α-Olefins". Catalysts 13, № 3 (16 березня 2023): 594. http://dx.doi.org/10.3390/catal13030594.

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The pretreatment atmosphere has a significant impact on the performance of iron-based catalysts in carbon dioxide (CO2) hydrogenation. In this study, we investigated the effects of carbon monoxide (CO), syngas (H2/CO), and hydrogen (H2) on the performance of iron-based catalysts during the pretreatment process. To evaluate the structural changes in catalysts after activation and reaction, we analyzed their morphology and particle size, the surface and bulk phase composition, carbon deposition, the desorption of linear α-olefins and reaction intermediates using transmission electron microscope (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Mössbauer spectroscopy (MES), temperature-programmed desorption (TPD), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). Raman and XPS showed that the H2 pretreatment catalyst caused the absence of iron carbides due to the lack of carbon source, and the CO and syngas pretreatment catalysts promoted the formation of carbon deposits and iron carbides. While the bulk phase of the CO and syngas pretreatment catalyst mainly consists of iron carbide (FeCx), XRD and MES revealed that the bulk phase of the H2 pretreatment catalyst primarily consisted of metallic iron (Fe) and iron oxide (FeOx). The composition of the phase is closely associated with its performance at the initial stage of the reaction. The formation of olefins and C5+ products is more encouraged by CO pretreatment catalysts than by H2 and syngas pretreatment catalysts, according to in situ DRIFTS evidence. Ethylene (C2H4)/propylene (C3H6)-TPD indicates that the CO pretreatment catalyst is more favorable for the desorption of olefins which improves the olefins selectivity. Based on the analysis of the TEM images, H2 pretreatment stimulated particle agglomeration and sintering. In conclusion, the results show that the CO-pretreatment catalyst has higher activity due to the inclusion of more FeOX and Fe3C. In particular, the presence of Fe3C was found to be more favorable for the formation of olefins and C5+ hydrocarbons. Furthermore, carbon deposition was relatively mild and more conducive to maintaining the balance of FeOx/FeCx on the catalyst surface.

10

Jalal, W., B. Pinel-Alloul, and G. Méthot. "Suivi à moyen terme des impacts écologiques des feux et des coupes forestières sur la communauté zooplanctonique des lacs de l'écozone boréale." Revue des sciences de l'eau 18 (April 12, 2005): 221–48. http://dx.doi.org/10.7202/705585ar.

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Cet article vise à évaluer les effets à moyen terme des feux et des coupes de forêt sur la biomasse, la richesse spécifique et la composition du zooplancton des lacs de la forêt boréale au Québec. L'étude a été réalisée durant trois ans (1996-1998) après les perturbations sur 3 sous-ensembles de lacs similaires au niveau de leur morphométrie, incluant 7 lacs naturels non perturbés sur leur bassin versant, 7 lacs affectés par des coupes sur plus de 43% de la surface du bassin versant et 7 lacs affectés par des feux sur plus de 50% de la surface du bassin versant. Notre étude indique que le zooplancton a une forte résilience aux perturbations des lacs de la forêt boréale par les feux et les coupes. Les assemblages d'espèces sont très stables et varient peu entre les lacs naturels et les lacs perturbés. Les Rotifères sont le seul groupe affecté par les perturbations; leur richesse spécifique et leur biomasse sont plus fortes dans les lacs perturbés que dans les lacs naturels. Les feux ont un effet d'eutrophisation plus marqué que les coupes. Dans les lacs affectés par les feux, les apports accrus de nutriments favorisent la croissance du phytoplancton puis des rotifères. Toutefois, dans les lacs affectés par les coupes, la forte couleur de l'eau due aux apports accrus en carbone organique dissous est un facteur limitant, et la hausse du phytoplancton et des rotifères est moins accentuée. La richesse spécifique et la biomasse des Crustacés (Cladocères, Copépodes Calanoïdes et Cyclopoïdes) ne varient pas avec les perturbations. Sur l'ensemble du suivi, le niveau de perturbation n'est pas fortement relié aux changements dans la biomasse des groupes taxinomiques qui s'expliquent plutôt par les variations annuelles de la température de l'eau et des concentrations en chlorophylle a.

11

Al-Qodami, Bilquis Ali, Heba H. Farrag, Sayed Youssef Sayed, Nageh K. Allam, Bahgat E. El-Anadouli, and Ahmad M. Mohammad. "Bifunctional Tailoring of Platinum Surfaces with Earth Abundant Iron Oxide Nanowires for Boosted Formic Acid Electro-Oxidation." Journal of Nanotechnology 2018 (December 3, 2018): 1–10. http://dx.doi.org/10.1155/2018/4657040.

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To expedite the marketing of direct formic acid fuel cells, a peerless inexpensive binary FeOx/Pt nanocatalyst was proposed for formic acid electro-oxidation (FAO). The roles of both catalytic ingredients (FeOx and Pt) were inspired by testing the catalytic performance of FAO at the FeOx/Au and FeOx/GC analogies. The deposition of FeOx proceeded electrochemically with a post‐activating step that identified the catalyst’s structure and performance. With a proper adaptation for the deposition and activation processes, the FeOx/Pt nanocatalyst succeeded to mitigate the typical CO poisoning that represents the principal element deteriorating the catalytic performance of the direct formic acid fuel cells. It also provided a higher (eightfold) catalytic efficiency than the bare Pt substrates toward FAO with a much better durability. Field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) were all employed to inspect, respectively, the surface morphology, bulk composition, and crystal structure of the catalyst. The electrochemical impedance spectra could correlate the charge transfer resistances for FAO over the inspected set of catalysts to explore the role of FeOx in mediating the reaction mechanism.

12

Камзин, А. С., I. M. Obaidat, В. С. Козлов, Е. В. Воронина, V. Narayanaswamy та I. A. Al-Omari. "Нанокомпозиты оксид графена/оксид железа (GrO/FeOx) для биомедицины: синтез и исследования". Физика твердого тела 63, № 6 (2021): 807. http://dx.doi.org/10.21883/ftt.2021.06.50944.004.

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Представлены исследования свойств и структуры магнитных нанокомпозитов оксид графена GrO/оксид железа FeOx, синтезированных механохимическим методом с различным содержанием компонент в весовых процентах, GrO : FeOx, а именно: 20 : 80, 50 : 50 и 80 : 20. Метод механохимического синтеза представляет собой механический процесс измельчения в шаровой мельнице в водной среде порошка оксида железа вместе с оксидом графена. Синтезированные магнитные нанокомпозиты GrO/FeOx исследованы методами рамановской спектроскопии, магнитометра с вибрирующим образцом и мёссбауэровской спектроскопии. Мёссбауэровские исследования позволили определить фазовый состав и структуру синтезированных магнитных нанокомпозитов GrO/FeOx. Данные мёссбауэровской спектроскопии показали, что композиты GrO/FeOx состоят из фазы магнетита Fe3O4 и магнитных наночастиц в парамагнитном состоянии, что согласуется с данными рентгеноструктурных исследований. По результатам мёссбауэровской спектроскопии установлено, что кроме магнетита в магнитных нанокомпозитах GrO/FeOx присутствует гематит alpha-Fe2O3, а также фазы, идентифицированные как карбиды железа и обедненные железом кластеры углерода. Последние не были обнаружены методом рентгеновской дифракции, по-видимому, потому, что их количество незначительно и они находятся в аморфном состоянии. Полученные результаты показывают, что графен является не просто источником углерода при помоле в шаровой мельнице, но обладает собственной реакционной способностью и способностью генерировать новые фазы при механохимической активации. На основании проведенных мёссбауэровских исследований получена уникальная и важная информация о магнитной структуре магнитных нанокомпозитов GrO/FeOx. Результаты исследований позволяют объяснить магнитные свойства магнитных нанокомпозитов GrO/магнитные частицы, что важно для разработки и синтеза с использованием оксида графена высокоэффективных магнитных нанокомпозитов для различных применений, в том числе, для биомедицины. Ключевые слова: нанокомпозит оксид графена/феррооксид, механохимический метод синтеза, мёссбауэровская спектроскопия.

13

Bailly, Sean. "Des feux de camp à la surface du Soleil." Pour la Science N° 515 - septembre, no. 9 (May 5, 2020): 10–11. http://dx.doi.org/10.3917/pls.515.0010.

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Rtimi, S., C. Pulgarin, R. Sanjines, and J. Kiwi. "Novel FeOx–polyethylene transparent films: synthesis and mechanism of surface regeneration." RSC Advances 5, no. 98 (2015): 80203–11. http://dx.doi.org/10.1039/c5ra14503a.

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15

Vannière, Boris, Didier Galop, Christine Rendu, and Bernard Davasse. "Feu et pratiques agro-pastorales dans les Pyrénées-Orientales : le cas de la montagne d'Enveitg (Cerdagne, Pyrénées-Orientales, France)." Sud-Ouest européen 11, no. 1 (2001): 29–42. http://dx.doi.org/10.3406/rgpso.2001.2765.

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La montagne d'Enveitg (Cerdagne, Pyrénées-Orientales) est depuis une dizaine d'années le cadre d'une recherche pluridisciplinaire intégrant archéologie pastorale et études paléoenvironnementales (palynologie, anthracologie, carpologie). Ces travaux ont permis d'appréhender la conquête et l'exploitation du milieu montagnard par les communautés agro-pastorales depuis le Néolithique. Cet article présente de nouveaux résultats acquis sur l'histoire des feux. Celle-ci peut être reconstituée par une étude des microcharbons de bois sédimentes dans un remplissage tourbeux (la tourbière d'altitude du Pla de l'Orri). L'analyse est réalisée sur la base d'une nouvelle méthodologie fondée sur des observations en microscopie à réflexion. Une reconstruction de l'occurrence des feux sur plus de sept millénaires est proposée et discutée en termes d'origine et d'intensité du signal.

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Pylarinou, Martha, Alexia Toumazatou, Elias Sakellis, Evangelia Xenogiannopoulou, Spiros Gardelis, Nikos Boukos, Athanasios Dimoulas, and Vlassis Likodimos. "Visible Light Trapping against Charge Recombination in FeOx–TiO2 Photonic Crystal Photocatalysts." Materials 14, no. 23 (November 23, 2021): 7117. http://dx.doi.org/10.3390/ma14237117.

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Tailoring metal oxide photocatalysts in the form of heterostructured photonic crystals has spurred particular interest as an advanced route to simultaneously improve harnessing of solar light and charge separation relying on the combined effect of light trapping by macroporous periodic structures and compositional materials’ modifications. In this work, surface deposition of FeOx nanoclusters on TiO2 photonic crystals is investigated to explore the interplay of slow-photon amplification, visible light absorption, and charge separation in FeOx–TiO2 photocatalytic films. Photonic bandgap engineered TiO2 inverse opals deposited by the convective evaporation-induced co-assembly method were surface modified by successive chemisorption-calcination cycles using Fe(III) acetylacetonate, which allowed the controlled variation of FeOx loading on the photonic films. Low amounts of FeOx nanoclusters on the TiO2 inverse opals resulted in diameter-selective improvements of photocatalytic performance on salicylic acid degradation and photocurrent density under visible light, surpassing similarly modified P25 films. The observed enhancement was related to the combination of optimal light trapping and charge separation induced by the FeOx–TiO2 interfacial coupling. However, an increase of the FeOx loading resulted in severe performance deterioration, particularly prominent under UV-Vis light, attributed to persistent surface recombination via diverse defect d-states.

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Li, Guobo, Weiwei Feng, Yiwei Luo, Jie Yan, Yining Cai, Yiling Wang, Shule Zhang, Wenming Liu, and Honggen Peng. "Unraveling FeOx Nanoparticles Confined on Fibrous Mesoporous Silica Catalyst Construction and CO Catalytic Oxidation Performance." Catalysts 14, no. 1 (January 14, 2024): 63. http://dx.doi.org/10.3390/catal14010063.

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Catalytic oxidation is used to control carbon monoxide (CO) emissions from industrial exhaust. In this study, a mesoporous silica material, KCC-1, was synthesized and used as a carrier with a high specific surface area to confine active component FeOx nanoparticles (NPs), and the CO catalytic oxidation performance of x%Fe@KCC-1 catalysts (x represents the mass loading of Fe) was studied. The experimental results showed that due to its large specific surface area and abundant mesopores, the FeOx NPs were highly dispersed on the surface of the KCC-1 carrier. The particle size of FeOx was very small, resulting in strong interactions between FeOx NPs and KCC-1, which enhanced the catalytic oxidation reaction on the catalyst. The FeOx loading improved the CO adsorption capability of the catalyst, which facilitated the catalytic oxidation of CO, with the 7%Fe@KCC-1 catalyst achieving 100% CO conversion at 160 °C. The CO catalytic removal mechanism was investigated by a combination of in-situ DRIFTS and DFT calculations. This study advances scientific understanding of the application potential of nano-catalysts in important oxidation reactions and provides valuable insights into the development of efficient CO oxidation catalysts.

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Waheed, Ammara, Quanquan Shi, Nobutaka Maeda, Daniel M. Meier, Zhaoxian Qin, Gao Li, and Alfons Baiker. "Strong Activity Enhancement of the Photocatalytic Degradation of an Azo Dye on Au/TiO2 Doped with FeOx." Catalysts 10, no. 8 (August 13, 2020): 933. http://dx.doi.org/10.3390/catal10080933.

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The doping of Au/TiO2 with FeOx is shown to result in a strong enhancement of its photocatalytic activity in the degradation of the azo dye Orange II. In order to examine the source of this enhancement, Au-FeOx/TiO2 nanocomposites containing different molar ratios of Au:Fe were synthesized, and X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), and high-resolution transmission electron microscope (HRTEM) analyses indicated that the TiO2-supported Au nanoparticles were partially covered with an amorphous layer of FeOx species, in which the iron was present as Fe2+ and Fe3+. The metal-semiconductor system, i.e., Au/TiO2, showed only a moderate degradation rate, whereas doping with FeOx strongly enhanced the degradation activity. The bandgap energy decreased gradually from Au/TiO2 (3.13 eV) to the catalyst with the highest FeOx loading Au-FeOx (1:2)/TiO2 (2.23 eV), and this decrease was accompanied by a steady increase in the degradation activity of the catalysts. XPS analyses revealed that compared to Au/TiO2, on Au-FeOx/TiO2 a much higher population density of chemisorbed and/or dissociated oxygen species was generated, which together with the decreased bandgap resulted in the highest photocatalytic activity observed with Au-FeOx (1:2)/TiO2. The processes occurring during reaction on the catalyst surface and in the bulk liquid phase were investigated using operando attenuated total reflection IR spectroscopy (ATR-IR) combined with modulation excitation spectroscopy (MES), which showed that the doping of Au/TiO2 with FeOx weakens the interaction of the dye with the catalyst surface and strongly enhances the cleavage of the azo bond.

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Kiwi, John, and Sami Rtimi. "Mechanisms of the Antibacterial Effects of TiO2–FeOx under Solar or Visible Light: Schottky Barriers versus Surface Plasmon Resonance." Coatings 8, no. 11 (November 4, 2018): 391. http://dx.doi.org/10.3390/coatings8110391.

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This study reports the significant mechanistic difference between binary-oxide antibacterial films with the same composition but different microstructures. Binary TiO2-FeOx films were found to present a faster bacterial inactivation kinetics under visible light irradiation than each single oxide acting independently. The interaction between the film active surface species and the bacteria within the disinfection period was followed by X-ray photoelectron spectroscopy (XPS) and provided the evidence for a redox catalysis taking place during the bacterial inactivation time. The optical and surface properties of the films were evaluated by appropriate surface analytical methods. A differential mechanism is suggested for each specific microstructure inducing bacterial inactivation. The surface FeOx plasmon resonance transferred electrons into the conduction band of TiO2 because of the Schottky barrier after Fermi level equilibration of the two components. An electric field at the interface between TiO2 and FeOx, favors the separation of the photo-generated charges leading to a faster bacterial inactivation by TiO2–FeOx compared to the bacterial inactivation kinetics by each of the single oxides.

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Batu, Matius Stefanus, Maria Magdalena Kolo, and Adolvina Kono. "Pemanfaatan Ekstrak Biji Feun Kase (Thevetia peruviana) sebagai Inhibitor Korosi Logam Seng dalam Media HCl." Jurnal Riset Kimia 13, no. 2 (September 30, 2022): 188–97. http://dx.doi.org/10.25077/jrk.v13i2.520.

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Feun Kase seed extract can be used as a corrosion inhibitor on zinc metal in HCl solution. This study aims to determine the secondary metabolites contained in Feun Kase seed extract, inhibition efficiency and corrosion rate, and surface morphology of zinc metal in the inhibition process using Feun Kase seed extract in HCl media. Feun Kase seed extract was obtained by maceration extraction using methanol. In the corrosion inhibition test, the concentration and temperature variations were carried out to determine the effect on the inhibition efficiency and the corrosion rate per year. The results showed that the methanol extract of Feun Kase seeds contained secondary metabolites of alkaloids, flavonoids and saponins. The optimum inhibition efficiency was obtained at an inhibitor concentration of 30 ppm of 82.70% with a corrosion rate of 5.80 mm/year and at a temperature of 35ºC of 75.84% with a corrosion rate of 7.28 mm/year in the test of increasing the temperature of the corrosion medium. The morphological analysis of the zinc plate using the SEM instrument showed that the zinc plate without surface treatment (not immersed in HCl media) was still smooth. This is indicated by the surface of the zinc plate which is still clearly visible because it has not been affected by the corrosion medium. The zinc plate when immersed in HCl media, is damaged which is indicated by the presence of pores or holes. Zinc plate when added with Feun Kase seed extract in HCl media, the zinc surface was damaged but the damage was not as prominent as in HCl media without using an inhibitor.

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Dong, Yaxin, Chenguang Su, Kai Liu, Haomeng Wang, Zheng Zheng, Wei Zhao, and Suhong Lu. "The Catalytic Oxidation of Formaldehyde by FeOx-MnO2-CeO2 Catalyst: Effect of Iron Modification." Catalysts 11, no. 5 (April 27, 2021): 555. http://dx.doi.org/10.3390/catal11050555.

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A series of FeOx-MnO2-CeO2 catalysts were synthesized by the surfactant-templated coprecipitation method and applied for HCHO removal. The influence of Fe/Mn/Ce molar ratio on the catalytic performance was investigated, and the FeOx-MnO2-CeO2 catalyst exhibited excellent catalytic activity, with complete HCHO conversion at low temperatures (40 °C) when the molar ratio of Fe/Mn/Ce was 2/5/5. The catalysts were characterized by N2 adsorption and desorption, XRD, H2-TPR, O2-TPD and XPS techniques to illustrate their structure–activity relationships. The result revealed that the introduction of FeOx into MnO2-CeO2 formed a strong interaction between FeOx-MnO2-CeO2, which facilitated the improved dispersion of MnO2-CeO2, subsequently increasing the surface area and aiding pore development. This promotion effect of Fe enhanced the reducibility and produced abundant surface-active oxygen. In addition, a great number of Oα is beneficial to the intermediate decomposition, whereas the existence of Ce3+ favors the formation of oxygen vacancies on the surface of the catalyst, all of which contributed to HCHO oxidation at low temperatures.

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Huang, Yao-Hui, Chun-Ping Huang, Yu-Wen Lu, and Chun-Yu Lo. "Oxidation and immobilization of iron and manganese by a fluidized bed reactor." Water Supply 9, no. 6 (December 1, 2009): 619–25. http://dx.doi.org/10.2166/ws.2009.677.

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An iron and manganese species immobilization technology was developed in a fluidized bed reactor (FBR) with a new fluidized media, immobilized iron oxide (namely FeOx-30). The FeOx-30 catalyst exhibited excellent performance as a catalyst for the oxidation of Mn2 + . About 95% and 30% of the manganese species were immobilized on FeOx-30 and silica sand in FBR, respectively. The oxidation rates of Fe2 + and Mn2 + and the immobilization efficiencies of iron and manganese oxides strongly depend on pH value. Usually during oxidization the pH values of the solution containing Fe2 + must be above 7, and Mn2 + must be above 9. During this study, large amounts of iron species leached from the surface of FeOx-30 only when manganese was in the system. The surface of the FeOx-30 became fragile in a single system. However, the removal of iron and manganese species simultaneously was better than only the removal of manganese in an FBR. In the binary system, the optimum pH condition for immobilization of both iron and manganese species was pHi 9. The higher catalyst loading in the binary system led to a higher removal efficiency of iron and manganese.

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Sun, Hong Gang, Hong Xia Li, and Wen Bin Jiao. "Corrosion of MgAl₂O₄Spinel with Different Al₂O₃ Contents in Iron-Containing Gasifier Slag." Solid State Phenomena 281 (August 2018): 118–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.118.

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The MgAl2O4 spinel ceramic specimens with five different alumina contents ( w(Al2O3)=66%,72%,78%,85%,90%) were prepared using alumina micropowder and magnesia micropowder as raw materials, after mixing, shaping, drying, and heating at 1800 °C. The crucible specimens were tested for slag corrosion with commercial gasifier slag at 1500 °C for 2 h under oxidazing and reducing atmosphere. The specimens before and after slag test were studied by analyzing the microstructure and element distributions of corroded specimens with XRD, SEM and EDS. The results show that the slow dissolution of spinel into slag was observed because a low melting point material was formed by spinel reacting with CaO and SiO2 in slag on the surface of the spinel block. Meanwhile, FeOx in the slag was absorbed around the surface of spinel block to form the multiple solid solution, which was composed of MgO-Al2O3-FeOx and had a denser microstructure. The absorption of FeOx in slag had contributed to the resistance to slag penetration for the spinel. The relationship between the absorption capacity of spinel on FeOx and the chemical composition of spinel was discussed.

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Presson, Jefry, Yakobus P. E. S. Agu, Marselina T. D. Tea, Lukas Pardosi, Eduardus Yosef Neonbeni, Risna Erni Yati Adu, Maria Magdalena Kolo, and Nugraha Kristiano Floresda Dethan. "Pelatihan Pembuatan Biodiesel Bagi Pemuda Di Desa Oeolo Provinsi NTT." Jurnal Pengabdian Masyarakat MIPA dan Pendidikan MIPA 7, no. 1 (March 24, 2023): 8–15. http://dx.doi.org/10.21831/jpmmp.v7i1.57356.

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Minyak Feun Kase merupakan bahan baku pembuatan biodiesel yang efektif karena tidak bersaing dengan sektor pangan. Walaupun tanaman Feun Kase banyak tersebar di Desa Oeolo, masyarakat setempat tidak mengetahui potensi dari tanaman ini. Oleh karena itu, kegiatan pelatihan pembuatan biodiesel ini penting dilakukan dengan tujuan meningkatkan pengetahuan masyarakat muda mengenai potensi Feun Kase sebagai biodiesel, dan meningkatkan minat terhadap disiplin ilmu berbasis teknologi. Dengan demikian, kerja keras Pemerintah Indonesia dan para peneliti dapat berjalan lancar karena didukung oleh masyarakat yang memiliki pengetahuan dan ketrampilan. Kegiatan ini dilakukan dalam 6 urutan dari persiapan material sampai survei akhir dengan metode yang bervariasi seperti ceramah, kuesioner, dan pendampingan. Peserta kegiatan ini adalah anak – anak muda Desa Oeolo dengan rentang umur 20 – 30 tahun. Melalui survei menggunakan kuesioner, terlihat bahwa terjadi peningkatan pengetahuan peserta dari nilai 25 (sebelum pelatihan) menjadi 83 (sesudah pelatihan). Dari hasil survei, dapat disimpulkan bahwa kegiatan ini berdampak pada peningkatan pengetahuan sebesar 233%.

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Lavoie, Martin, Alayn C. Larouche, and Pierre J. H. Richard. "Conditions du développement de la tourbière de Farnham, Québec." Géographie physique et Quaternaire 49, no. 2 (November 30, 2007): 305–16. http://dx.doi.org/10.7202/033044ar.

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RÉSUMÉ Les analyses polliniques et macrofossiles d'une carotte de sédiments provenant de la marge de la tourbière de Farnham ont permis de retracer cinq étapes dans le développement de la tourbière. L'accumulation des sédiments a débuté au sein d'un marais situé au centre de la dépression à la suite du retrait de la Mer de Champlain vers 8500 ans BP. L'entourbement centrifuge subséquent a atteint le point d'échantillonnage vers 8100 ans BP. À cette époque, un mélèzin (1) a laissé place en quelques décennies à un fen arboré (2) jusque vers 6900 ans BP. Par la suite, un fen au couvert arborescent très ouvert (3) s'est mis en place et des mares se sont constituées à la surface de la tourbière jusque vers 5800 ans BP. L'accumulation de la tourbe a provoqué (4) l'ombrotrophication de la tourbière, ce changement trophique ayant persisté jusqu'à nos jours. L'action des feux et l'activité anthropique ont entraîné récemment (5) l'implantation d'espèces arborescentes de milieux perturbés. L'entourbement et les différentes étapes du développement de la marge de la tourbière ont été déterminés par l'accumulation de la tourbe, l'hydrologie locale, le climat et les feux. La formation des mares à la surface de la tourbière vers 6900 ans BP, à la charnière entre les régimes de fen et de bog, ainsi que l'expansion synchrone de Tsuga canadensis au sein des forêts environnantes, témoignent de conditions climatiques plus humides associées à une hausse des précipitations ou à une baisse de l'évapotranspiration.

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Li, Jingkun, Qingying Jia, Sanjeev Mukerjee, Moulay-Tahar Sougrati, Goran Drazic, Andrea Zitolo, and Frédéric Jaouen. "The Challenge of Achieving a High Density of Fe-Based Active Sites in a Highly Graphitic Carbon Matrix." Catalysts 9, no. 2 (February 2, 2019): 144. http://dx.doi.org/10.3390/catal9020144.

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As one of the most promising platinum group metal-free (PGM-free) catalysts for oxygen reduction reaction (ORR), Fe–N–C catalysts with a high density of FeNx moieties integrated in a highly graphitic carbon matrix with a proper porous structure have attracted extensive attention to combine the high activity, high stability and high accessibility of active sites. Herein, we investigated a ZnCl2/NaCl eutectic salts-assisted ionothermal carbonization method (ICM) to synthesize Fe–N–C catalysts with tailored porous structure, high specific surface area and a high degree of graphitization. However, it was found to be challenging to anchor a high density of FeNx sites onto highly graphitized carbon. Iron precursors with preexisting Fe–N coordination were required to form FeNx sites in the nitrogen-doped carbon with a high degree of graphitization, while individual Fe and N precursors led to a Fe–N–C catalyst with poor-ORR activity. This provides valuable insights into the synthesis-structure relationship. Moreover, the FeNx moieties were identified as the major active sites in acidic conditions, while both FeNx sites and Fe2O3 were found to be active in alkaline medium.

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Hirai, Tomomi, Yosuke Hayashi, and Shinji Iwamoto. "Visible-Light Sensitive Photocatalytic Activity of FeO_x- and P-Modified TiO₂ with Rutile Structure." Advanced Engineering Forum 38 (November 2020): 23–27. http://dx.doi.org/10.4028/www.scientific.net/aef.38.23.

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Nanocrystalline rutile TiO2 particles were prepared via hydrothermal treatment of Ti-containing precursors obtained by low-temperature aging for a transparent diluted HCl solution of amorphous TiO2. The products were modified with FeOx and phosphoric acid, and the photocatalytic activities of the obtained catalysts under visible-light irradiation were examined. By the addition of FeOx or phosphoric acid, the photocatalytic activity of the rutile TiO2 was slightly increased. On the contrary, by the FeOx loading and subsequent addition of phosphoric acid, significant increases in the photocatalytic activity were attained. Results of UV-vis suggest that the iron oxides formed on the surface of rutile TiO2 were changed into highly dispersed iron phosphate species by the addition of phosphoric acid. It was presumed that these species effectively suppress the recombination reaction between the photogenerated electrons and holes and contribute to the high photocatalytic activity of the rutile TiO2 photocatalysts modified with FeOx and phosphoric acid.

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Li, Zhaoyang, Geng Chen, Zhenghua Shao, Haonan Zhang, and Xiujuan Guo. "The Effect of Iron Content on the Ammonia Selective Catalytic Reduction Reaction (NH3-SCR) Catalytic Performance of FeOx/SAPO-34." International Journal of Environmental Research and Public Health 19, no. 22 (November 10, 2022): 14749. http://dx.doi.org/10.3390/ijerph192214749.

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Iron-based catalysts are regarded as promising candidates for the ammonia selective catalytic reduction reaction (NH3-SCR) which show good catalytic activity at medium and high temperatures, whereas SAPO-34 molecular sieves have a micro-pore structure and are ideal catalyst carriers. In this paper, four FeOx/SAPO-34 molecular sieve catalysts with different iron contents (Fe = 1%, 2%, 3%, 4%) were prepared using an impregnation method. The effect of iron content on the surface properties and catalytic activity was investigated by a series of characterization techniques including XRD, SEM, BET, XPS, H2-TPR and NH3-TPD. Iron species in the FeOx/SAPO-34 catalysts exist in the form of isolated iron ions or well-dispersed small crystals and iron oxide species clusters. With the addition of iron content, the integrity of CHA (chabazite) zeolite structure remained, but the crystallinity was affected. The FeOx/SAPO-34 catalyst with 3% Fe loading showed a relatively flat surface with no large-diameter particles and strong oxidation-reduction ability. Meanwhile, more acidic sites are exposed, which accelerated the process of catalytic reaction. Thus, the FeOx/SAPO-34 catalyst with 3% Fe showed the best NO conversion performance among the four catalysts prepared and maintained more than 90% NO conversion efficiency in a wide temperature range from 310 °C to 450 °C.

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Choi, Boyun, Gun-Woo Park, Jong-Ryul Jeong, and Nari Jeon. "Comparative Study of Thermal and Plasma-Enhanced Atomic Layer Deposition of Iron Oxide Using Bis(N,N′-di-butylacetamidinato)iron(II)." Nanomaterials 13, no. 12 (June 14, 2023): 1858. http://dx.doi.org/10.3390/nano13121858.

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Only a few iron precursors that can be used in the atomic layer deposition (ALD) of iron oxides have been examined thus far. This study aimed to compare the various properties of FeOx thin films deposited using thermal ALD and plasma-enhanced ALD (PEALD) and to evaluate the advantages and disadvantages of using bis(N,N′-di-butylacetamidinato)iron(II) as an Fe precursor in FeOx ALD. The PEALD of FeOx films using iron bisamidinate has not yet been reported. Compared with thermal ALD films, PEALD films exhibited improved properties in terms of surface roughness, film density, and crystallinity after they were annealed in air at 500 °C. The annealed films, which had thicknesses exceeding ~ 9 nm, exhibited hematite crystal structures. Additionally, the conformality of the ALD-grown films was examined using trench-structured wafers with different aspect ratios.

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Clément, Vincent. "Les feux de forêt en Méditerranée : un faux procès contre Nature." Espace géographique 34, no. 4 (2005): 289. http://dx.doi.org/10.3917/eg.344.0289.

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Parks, W. Hays. "Le protocole sur les armes incendiaires." Revue Internationale de la Croix-Rouge 72, no. 786 (December 1990): 584–604. http://dx.doi.org/10.1017/s0035336100005128.

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Depuis le jour où l'homme a découvert le feu et commencé à imaginer différents moyens de l'utiliser pour assurer à la fois la survie de l'espèce et le progrès, il a eu aussi recours au feu comme arme de destruction. Dans l'Art de la Guerre, Sun Tsu (500 av.J.-C.) parle de flèches incendiaires, tandis que, dans La Guerre du Péloponèse, Thucydide décrit une arme incendiaire utilisée à Sparte en 42 av.J.-C. Dans Le Déclin et la Chute de l'Empire romain, Edward Gibbon attribue le succès emporté par les Romains à Constantinople en 1453 ap.J.-C. au «feu grec», ce feu grégeois obtenu en enflammant un mélange de naphte, de poix et de résine et en le répandant à la surface des eaux. Près de cinq siècles plus tard, craignant une invasion, la Grande-Bretagne a utilisé le feu grégeois pour défendre ses côtes en 1940.

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Xu, Xuejun, Qiang Fu, Lin Gan, Jing Zhu, and Xinhe Bao. "Interface-Confined FeOx Adlayers Induced by Metal Support Interaction in Pt/FeOx Catalysts." Journal of Physical Chemistry B 122, no. 2 (September 26, 2017): 984–90. http://dx.doi.org/10.1021/acs.jpcb.7b07644.

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Gannavarapu, Krishna Prasad, Megha Thakkar, Sidhartha Veerapaga, Liping Wei, Rajesh Babu Dandamudi, and Somenath Mitra. "Novel diatom-FeOx composite as highly active catalyst in photodegradation of Rhodamine-6G." Nanotechnology Reviews 7, no. 3 (June 27, 2018): 247–55. http://dx.doi.org/10.1515/ntrev-2017-0218.

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Abstract We report the study of nanoporous silica-iron oxide composite generated from diatom frustules as a highly active catalyst for the photodegradation of the dye Rhodamine-6G. The unique architecture and high surface area of diatoms were utilized to immobilize iron oxide on their surface to form the composite. Photodegradation was carried out under 365-nm radiation and was observed using the absorption spectrum of the dye. The reaction was found to follow pseudo-first-order kinetics. The results were compared with commercially available granular iron oxide. The rate constant K (min−1) for photodegradation by the diatom composite was found to be as high as 0.0584 min−1 for diatom-FeOx composites, which is 52% higher than 0.0273 min−1 for granular FeOx at a dye concentration of 0.02 mm. The unique structural morphology and the synthetic strategy have led to the composites showing superior activity in the degradation of the dye Rhodamine-6G.

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MATSUURA, Hiroyuki, and Fumitaka TSUKIHASHI. "Surface Active Effect of Na2O on the Rate of CO2 Dissociation on the Surface of Molten FeOx-Na2O and FeOx-SiO2-Na2O Systems." ISIJ International 45, no. 7 (2005): 1035–40. http://dx.doi.org/10.2355/isijinternational.45.1035.

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Kamal, Sanarya K., and Ammar S. Abbas. "Textural Properties Characterization for NaX and FeX Zeolites by Nitrogen Adsorption-desorption Technique." Iraqi Journal of Chemical and Petroleum Engineering 23, no. 4 (December 30, 2022): 33–41. http://dx.doi.org/10.31699/ijcpe.2022.4.5.

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The zeolite's textural properties have a significant effect on zeolite's effectiveness in the different industrial processes. This research aimed to study the textual properties of the NaX and FeX zeolites using the nitrogen adsorption-desorption technique at a constant low temperature. According to the International Union of Pure and Applied Chemistry, the adsorption-desorption isotherm showed that the studied materials were mixed kinds I/II isotherms and H3 type hysteresis. The Brunauer-Emmett-Teller isotherm was the best model to describe the nitrogen adsorption-desorption better than the Langmuir and Freundlich isotherms. The obtained adsorption capacity and Brunauer-Emmett-Teller surface area values for NaX were greater than FeX. According to the Kelvin equation, Barrett, Joyner, and Halenda model was used to determine pore size distribution, diameter, and average pore volume for the selected zeolites. The pore size distribution for NaX was wider than FeX zeolites, the pore diameter for NaX was less than FeX, and the average pore volume for FeX was greater than the value of NaX average pore volume. The comparative study was carried out with the previous studies, and the comparison showed that the textual properties of the modified zeolites agreed with other studies.

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Dorso, Franck. "Feux nocturnes d'Edirnekapı. Territoires de l'informel et évolutions des régulations urbaines à Istanbul." Annales de géographie 700, no. 6 (2014): 1285. http://dx.doi.org/10.3917/ag.700.1285.

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Nolan, Michael, Anna Iwaszuk, and Hiroaki Tada. "Molecular Metal Oxide Cluster-Surface Modified Titanium(IV) Dioxide Photocatalysts." Australian Journal of Chemistry 65, no. 6 (2012): 624. http://dx.doi.org/10.1071/ch11451.

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The surface modification of TiO2 with molecular sized metal oxide clusters has recently been shown to be a promising approach for providing TiO2 with visible-light activity and/or improved UV activity. This short review summarizes the effects of the surface modification of TiO2 with the oxides of iron and tin selected from d- and p-blocks, respectively, on the photocatalytic activity. Fe(acac)3 and [Sn(acac)2]Cl2 chemisorption on the TiO2 surface occurs by ligand-exchange and ion-exchange, respectively. Taking advantage of the strong adsorption, we formed extremely small metal oxide clusters on TiO2 by the chemisorption–calcination cycle (CCC) technique with their loading amount strictly controlled. The iron oxide surface modification of P-25 (anatase/rutile = 4 : 1, w/w, Degussa) gives rise to a high level of visible-light activity and a concomitant increase in the UV-light activity for the degradation of model organic pollutants. On the other hand, only the UV-light activity is increased by the tin oxide surface modification of ST-01 (anatase, Ishihara Sangyo). This striking difference can be rationalized on the basis of the material characterization and DFT calculations, which show that FeOx surface modification of rutile leads to visible-light activity, while SnO2-modified anatase enhances only the UV-light activity. We propose the mechanisms behind the FeOx and SnO2 surface modification, where the surface-to-bulk and bulk-to-surface interfacial electron transfer are taken into account in the former and the latter, respectively.

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Sourav, Sagar, and Israel E. Wachs. "Cr-Free, Cu Promoted Fe Oxide-Based Catalysts for High-Temperature Water-Gas Shift (HT-WGS) Reaction." Catalysts 10, no. 3 (March 6, 2020): 305. http://dx.doi.org/10.3390/catal10030305.

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Ca, Ni, Co, and Ge promoters were examined as potential candidates to substitute for the current toxic Cr in Cu-promoted Fe oxide-based catalysts for the HT-WGS reaction. The Ca and Ni promoters were found to improve catalyst performance relative to promotion with Cr. The HS-LEIS surface analysis data demonstrate that Ca and Ge tend to segregate on the surface, while Ni, Co, and Cr form solid solutions in the Fe3O4 bulk lattice. The corresponding number of catalytic active sites, redox, and WGS activity values of the catalysts were determined with CO-TPR, CO+H2O-TPSR, and SS-WGS studies, respectively. The poorer HT-WGS performances of the Ge and Co promoters are related to the presence of surface Ge and Co that inhibits catalyst redox ability, with the Co also not stabilizing the surface area of the Fe3O4 support. The Ni promoter uniformly disperses the Cu nanoparticles on the catalyst surface and increases the number of FeOx-Cu interfacial redox sites. The Ca promoter on the catalyst surface, however, enhances the activity of the FeOx-Cu interfacial redox sites. The CO+H2O TPSR results reveal that the redox ability of the active sites follows the SS-WGS performance of the catalysts and show the following trend: 3Cu8CaFe > 3Cu8NiFe ≥ 3Cu8CrFe > 3Cu8CoFe >> 3Cu8GeFe. Furthermore, all the catalysts followed a redox-type reaction mechanism for the HT-WGS reaction.

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Chen, Chunlin, Ling Zhang, Liming Lu, and Shouyi Sun. "Thermodynamic Calculation of Liquidus Surface of FeOx–CaO–SiO2 System." ISIJ International 50, no. 11 (2010): 1523–31. http://dx.doi.org/10.2355/isijinternational.50.1523.

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40

Melese, Asmare, Heluf Gebrekidan, Markku Yli-Halla, and Birru Yitaferu. "Phosphorus Status, Inorganic Phosphorus Forms, and Other Physicochemical Properties of Acid Soils of Farta District, Northwestern Highlands of Ethiopia." Applied and Environmental Soil Science 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/748390.

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Soil acidity and low availability of P limit crop production in the highlands of Ethiopia. The objective of this study was to determine the P status, distribution and forms of inorganic P and relate them to selected chemical properties of eight representative acidic surface soil samples from Farta District. Soil pH (H2O) varied between 4.74 and 5.50. The moderate to high CEC suggests that besides kaolinite, the soils also contain expandable 2 : 1 clay minerals. Though the total P content was high, the available Olsen P content was very low or low in all soils except one. In most soils, the abundance of inorganic P fractions was as follows: P bound by oxalate extractable iron (Feox-P)>reductant soluble Fe-P>occluded Al-Fe-P>P bound by oxalate extractable aluminum (Alox-P)>calcium bound P (Ca-P). Olsen P had a very strong positive correlation (P≤0.01) withAlox-P (r=0.98),Feox-P (r=0.96), and oxalate extractable P (r=0.94). Though Fe bound P reserves were quite abundant and the degree of P saturation ofAlox+Feox(median 3.3%) was moderate, the extremely low P saturation ofAlox(median 0.5%) explains the P deficiency of the soils.

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Sanchis, Rut, Daniel Alonso-Domínguez, Ana Dejoz, María Pico, Inmaculada Álvarez-Serrano, Tomás García, María López, and Benjamín Solsona. "Eco-Friendly Cavity-Containing Iron Oxides Prepared by Mild Routes as Very Efficient Catalysts for the Total Oxidation of VOCs." Materials 11, no. 8 (August 9, 2018): 1387. http://dx.doi.org/10.3390/ma11081387.

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Iron oxides (FeOx) are non-toxic, non-expensive and environmentally friendly compounds, which makes them good candidates for many industrial applications, among them catalysis. In the present article five catalysts based on FeOx were synthesized by mild routes: hydrothermal in subcritical and supercritical conditions (Fe-HT, Few200, Few450) and solvothermal (Fe-ST1 and Fe-ST2). The catalytic activity of these catalysts was studied for the total oxidation of toluene using very demanding conditions with high space velocities and including water and CO2 in the feed. The samples were characterized by X-ray diffraction (XRD), scanning and high-resolution transmission electron microscopy (SEM and HRTEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. It was observed that the most active catalyst was a cavity-containing porous sample prepared by a solvothermal method with a relatively high surface area (55 m2 g−1) and constituted by flower-like aggregates with open cavities at the catalyst surface. This catalyst displayed superior performance (100% of toluene conversion at 325 °C using highly demanding conditions) and this performance can be maintained for several catalytic cycles. Interestingly, the porous iron oxides present not only a higher catalytic activity than the non-porous but also a higher specific activity per surface area. The high activity of this catalyst has been related to the possible synergistic effect of compositional, structural and microstructural features emphasizing the role of the surface area, the crystalline phase present, and the properties of the surface.

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Xu, Hong, Qiang Fu, and Xinhe Bao. "Nanosized FeOx overlayers on Pt-skin surfaces for low temperature CO oxidation." Chinese Journal of Catalysis 34, no. 11 (November 2013): 2029–35. http://dx.doi.org/10.1016/s1872-2067(12)60673-1.

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43

Tang, Ke Qin, Ke Hua Zhong, Yan Ming Cheng, Zhi Gao Chen, and Zhi Gao Huang. "The Influence of Spin Orientation and Alloying on Magnetism and Work Function for Fe_x-1Mn_x/Fe (001) Films." Advanced Materials Research 629 (December 2012): 229–35. http://dx.doi.org/10.4028/www.scientific.net/amr.629.229.

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By using first-principles methods based on density functional theory (DFT), we investigated the magnetism and work function of Fex-1Mnx/Fe (001) films with different spin arrangements (parallel (PL), antiparallel (APL1) and mixed (APL2)) for Mn and Fe atoms. The calculation shows that the spin arrangement and alloying have evident impact on the work function and moment of Fex-1Mnx/Fe (001) films. For Mn/Fe (001), the spin arrangement affects evidently the geometrical structure, work function and magnetism of the system. Moreover, the work function for non-magnetic (NM) state is found to be higher than that for magnetic state, and the work function of Mn/Fe (001) with PL state is less than that with APL2 state. For Fex-1Mnx/Fe (001), with increased Mn doping content, the Fe moments in the second layer decrease and their values are all less than the bulk value of Fe atom, which is due to the antiferromagnetic coupling between Mn and Fe atoms. Furthermore, we found that the surface alloying can have an impact on the work function of Fex-1Mnx/Fe (001), but the role of spin polarization is also quite important.

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Mayrand, Maxence. "Hyperkähler metrics near Lagrangian submanifolds and symplectic groupoids." Journal für die reine und angewandte Mathematik (Crelles Journal) 2022, no. 782 (October 26, 2021): 197–218. http://dx.doi.org/10.1515/crelle-2021-0059.

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Abstract The first part of this paper is a generalization of the Feix–Kaledin theorem on the existence of a hyperkähler metric on a neighborhood of the zero section of the cotangent bundle of a Kähler manifold. We show that the problem of constructing a hyperkähler structure on a neighborhood of a complex Lagrangian submanifold in a holomorphic symplectic manifold reduces to the existence of certain deformations of holomorphic symplectic structures. The Feix–Kaledin structure is recovered from the twisted cotangent bundle. We then show that every holomorphic symplectic groupoid over a compact holomorphic Poisson surface of Kähler type has a hyperkähler structure on a neighborhood of its identity section. More generally, we reduce the existence of a hyperkähler structure on a symplectic realization of a holomorphic Poisson manifold of any dimension to the existence of certain deformations of holomorphic Poisson structures adapted from Hitchin’s unobstructedness theorem.

45

Rey, Violette. "Feu l'Europe de l'Est ?" Annales de Géographie 99, no. 555 (1990): 564–78. http://dx.doi.org/10.3406/geo.1990.20996.

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46

Hong, Sung-Jei, Ajin Jo, Sang Hyeok Hong, Byeong Jun Kim, Young Sung Kim, Suwon Yang, and Jae-Yong Lee. "Effect of Polyvinylpolypyrrolidone Surfactant on Characteristics of Iron-Oxide Nanoparticles Synthesized by Using Recycled Waste Permanent Magnets." Micromachines 13, no. 11 (November 19, 2022): 2020. http://dx.doi.org/10.3390/mi13112020.

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In this study, iron oxide nanoparticles (FeOx NPs) were synthesized by using Fe solution recycled from NdFeB permanent magnet scrap. Furthermore, the effect of polyvinylpolypyrrolidone (PVP) as a surfactant on the characteristics of the FeOx NPs was investigated. Firstly, Fe solution was prepared by using 10% H2SO4 solution and Na2SO4 salt. In addition, three reducing agent solutions were prepared by dissolving PVP in 0.5 M NH4OH solution in distilled (D.I.) water with concentrations of 0 wt%, 1 wt%, and 2 wt%, respectively. Each reducing agent solution was added dropwise into the Fe solution to precipitate three precursors of FeOx NPs, and they were heat-treated at 400 °C to prepare three FeOx NPs samples, P0, P1, and P2. In X-ray diffractometer (XRD) analysis, diffraction peaks of P0 sample are consistent with the Fe3O4 with (311) preferred orientation. The XRD peak shifted from Fe3O4 to Fe2O3 structure as PVP concentration increased, and the crystal structure of P2 sample was transformed to Fe2O3 with (104) preferred orientation. Brunauer, Emmett, and Teller (BET) specific surface area increased in proportional to PVP concentration. HRTEM observation also supported the tendency; the particle size of the P0 sample was less than 40 nm, and particle size decreased as PVP concentration increased, leading to the particle size of the P2 sample being less than 20 nm in width. In addition, particle morphology started to be transformed from particle to rod shape as PVP concentration increased and, in the P2 sample, all the morphology of particles was transformed to a rod shape. Magnetic properties analysis revealed that the P0 sample exhibited the highest value of magnetic moment, 65.6 emu/g, and the magnetic moment was lowered in the P1 sample, and the P2 sample exhibited the lowest value of magnetic moment, 2.4 emu/g.

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Uzoho, Bethel, Nnaemeka Okoli, and Ugochi Ekwugha. "Impact of Texture on Sesquioxide Distribution in Southeastern Nigerian Soils." International Journal of Environment 8, no. 1 (March 16, 2019): 43–58. http://dx.doi.org/10.3126/ije.v8i1.23148.

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Sesquioxides which play significant roles in soil classification and dominant soil properties vary in soils with particle size fractions. Using randomized complete block design, this study was conducted in the month of June 2018 to evaluate the impact of texture on sesquioxide distribution in humid rainforest soils of Southeastern Nigeria. Four mini-pedons were dug at four landscape positions (upslope, midslope, downslope and flat surface) and triplicate soil samples taken from 0-20, 20-40 and 40-60 cm depths, summing to total of 36 samples. Crystalline and amorphous Al, Fe, Mn and Si oxides were then determined at a depth of 0-20 cm using Dithionate Citrate Bicarbonate (DCB) and ammonium oxalate reagents. Dithionate and oxalate fractions in bulk soil ranged between 9300-11,400 (Fed), 390-1580 (Feox), 4600-6700 (Ald), 660-890 (Alox), 3300-5600 (Mnd), 350-580 (Mnox) and 9600-13,500 (Sid) and 1690-1790 mg kg-1 (Siox), with dithionate superior indicating high crystallinity and low mobility of the sesquioxides. Ratios of bulk soil oxalate/dithionate fractions were low and ranged between 0.04-0.17 (Feox/Fed), 0.11-0.15 (Alox/Ald), 0.10-0.16(Mnox/Mnd) and 0.13-0.18 (Siox/Sid) and confirming their crystallinity. Low Feox/Fed ratios signified that soils were well drained (< 0.35), old (< 0.65) and highly weathered (< 0.50) with the order being a decreasing sequence of upslope > flat surface > down slope > midslope. Sesquioxide contents and reactivity in soil particle size fractions (sand, silt and clay) varied with landscapes. Regression models indicated that particle size fractions accounted for 50% of 2/3rd of the bulk soil sesquioxide concentrations and that averaged over landscapes, sand fraction was more enriched with various sesquioxides than the other soil particle size fractions. Correlations between most bulk soil sesquioxide fractions and sesquioxide fractions with selected soil properties (sand, silt, clay, moisture content, total porosity, organic matter, pH, Ca and ECEC) were significant (P < 0.05).

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Liu, Shiyang, Quentin Meyer, Yibing Li, Tingwen Zhao, Zhen Su, Karin Ching, and Chuan Zhao. "Fe–N–C/Fe nanoparticle composite catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells." Chemical Communications 58, no. 14 (2022): 2323–26. http://dx.doi.org/10.1039/d1cc07042h.

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49

Métailié, Jean-Paul, and Johanna Faerber. "Quinze années de gestion des feux pastoraux dans les Pyrénées : du blocage à la concertation." Sud-Ouest européen 16, no. 1 (2003): 37–51. http://dx.doi.org/10.3406/rgpso.2003.2837.

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Fiftteen years of pastoral fires management : from mental block to consultation. Management of pastures by the use of fire is a common practice in the Pyrenees, linked to moorlands vegetation dynamics. Fallow lands spreading and changes in land use are increasing difficulties for the traditional burning practice. This evolution provoked during the last 15 years the creation of local prescribed burning commitées, to improve the use of fire, decrease the risks and conciliate the various land uses. The evolution of fire practices emphazises the mountain management problems : fallow lands and maintenance of livestock farming, tourism development, management of landscape, woodlands and ecological resources, etc.

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Ramazanov, Shikhgasan, Ştefan Ţălu, Dinara Sobola, Farid Orudzev, Guseyn Ramazanov, Daud Selimov, Pavel Kaspar, Robert Macků, and Anton Nazarov. "Crack resistance of bismuth ferrite films obtained on a flexible substrate." E3S Web of Conferences 295 (2021): 04008. http://dx.doi.org/10.1051/e3sconf/202129504008.

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Ultrathin BiOx and FeOx layers were obtained by Atomic Layer Deposition (ALD) on the surface of a flexible Kapton substrate (poly (4,4’-oxydiphenylene-pyromellitimide)) at a temperature of 250 °C. The layer thickness was 50 - 100 nm. Surface morphology, electrical polarization, and mechanical properties were investigated by Atomic Force Microscope, Piezoelectric Force Microscopy and Force Modulation Microscopy. Chemical analysis was performed by X-ray Photoelectron Spectroscopy, where the formation of Bi2O3 and Fe2O3 phases, as well as intermediate phases in the Bi-Fe-O system, was observed. With a small increase in the Bi content of the film, the BFO / Kapton structure becomes more crack resistant. Modification of the Kapton surface with bismuth and iron oxides showed that such a composition exhibits multiferroic behavior.

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