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Academic literature on the topic 'Hydroxydes à base de Co'

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Published: 25 May 2024

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Journal articles on the topic "Hydroxydes à base de Co"

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Boukari, Y., G. Matejka, B. Parinet, and P. Simon. "La mise à l'équilibre des eaux tropicales : conséquences sur la déferrisation." Revue des sciences de l'eau 1, no. 4 (April 12, 2005): 339–53. http://dx.doi.org/10.7202/705016ar.

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L'étude de l'équilibre calco-carbonique d'une eau souterraine de l'Afrique de l'Ouest par la méthode de LEGRAND et POIRIER, a conduit à la détermination des conditions de traitement pour neutraliser l'agressivité naturelle de l'eau, due essentiellement à une forte teneur en acide carbonique et réduire ainsi son caractère corrosif. le problème de l'évolution du fer présent en relation avec la mise à l'équilibre a été également étudiée. L'application réalisée sur un pilote de laboratoire a permis d'optimiser les principales étapes du traitement, c'est-à-dire l'addition d'une base forte, la précipitation et la filtration des hydroxydes ferriques qui se forment à la suite de la neutralisation de l'acide carbonique.
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Martínez T, L. M., A. Muñoz, A. Pérez, O. H. Laguna, L. F. Bobadilla, M. A. Centeno, and J. A. Odriozola. "The effect of support surface hydroxyls on selective CO methanation with Ru based catalysts." Applied Catalysis A: General 641 (July 2022): 118678. http://dx.doi.org/10.1016/j.apcata.2022.118678.

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Wu, Yingquan, Li Tan, Tao Zhang, Hongjuan Xie, Guohui Yang, Noritatsu Tsubaki, and Jiangang Chen. "Effect of Preparation Method on ZrO2-Based Catalysts Performance for Isobutanol Synthesis from Syngas." Catalysts 9, no. 9 (September 6, 2019): 752. http://dx.doi.org/10.3390/catal9090752.

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Two types of amorphous ZrO2 (am-ZrO2) catalysts were prepared by different co-precipitation/reflux digestion methods (with ethylenediamine and ammonia as the precipitant respectively). Then, copper and potassium were introduced for modifying ZrO2 via an impregnation method to enhance the catalytic performance. The obtained catalysts were further characterized by means of Brunauer-Emmett-Teller surface areas (BET), X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), and In situ diffuse reflectance infrared spectroscopy (in situ DRIFTS). CO hydrogenation experiments were performed in a fixed-bed reactor for isobutanol synthesis. Great differences were observed on the distribution of alcohols over the two types of ZrO2 catalysts, which were promoted with the same content of Cu and K. The selectivity of isobutanol on K-CuZrO2 (ammonia as precipitant, A-KCZ) was three times higher than that on K-CuZrO2 (ethylenediamine as precipitant, E-KCZ). The characterization results indicated that the A-KCZ catalyst supplied more active hydroxyls (isolated hydroxyls) for anchoring and dispersing Cu. More importantly, it was found that bicarbonate species were formed, which were ascribed as important C1 species for isobutanol formation on the A-KCZ catalyst surface. These C1 intermediates had relatively stronger adsorption strength than those adsorbed on the E-KCZ catalyst, indicating that the bicarbonate species on the A-KCZ catalyst had a longer residence time for further carbon chain growth. Therefore, the selectivity of isobutanol was greatly enhanced. These findings would extend the horizontal of direct alcohols synthesis from syngas.
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Feng, Longsheng, D. Lv, R. K. Rhein, J. G. Goiri, M. S. Titus, A. Van der Ven, T. M. Pollock, and Y. Wang. "Shearing of γ’ particles in Co-base and Co-Ni-base superalloys." Acta Materialia 161 (December 2018): 99–109. http://dx.doi.org/10.1016/j.actamat.2018.09.013.

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Koriko, Moursalou, Sanonka Tchegueni, Fouad Alassani, Koffi Agbegnigan Degbe, and Gado Tchangbedji. "Extraction Et Caractérisation Physico-Chimique D’un Sel Végétal À Partir De La Cendre Du Palmier À Huile Du Nord Du Togo." European Scientific Journal ESJ 17, no. 43 (December 31, 2021): 102–15. http://dx.doi.org/10.19044/esj.2021.v17n43p102.

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Ce présent travail a porté sur l’extraction et la caractérisation physico-chimique d’un sel végétal fabriqué à base du palmier à huile. L’incinération des branches de palmier à huile donne une cendre qui, par lavage et évaporation donne du sel de palme. L’analyse de la solution obtenue après lavage de cette cendre à l’eau distillée par photométrie à flamme, spectrométrie à absorption atomique et par volumétrie révèle la présence de sodium (84,500 mg/L), potassium (1120 mg/L), calcium (44 mg/L) et magnésium (0,022 mg/L). Ce résultat indique que cette solution est très riche en potassium qu’en sodium et calcium ; le magnésium est présent sous forme de trace. En outre, l’analyse de la cendre obtenue à base de la rafle a révélé que les teneurs en potassium (3331,410 mg/L) et en sodium (497 mg/L) de la rafle sont plus élevées que celles de la branche du palmier à huile. Cependant, le dosage des anions dans une solution obtenue par dissolution de 10 grammes de sel de palme dans un litre d’eau distillée révèle la présence de chlorures (3153,460 mg/L), des hydroxydes (0,289 mg/L), des carbonates (0,180 mg/L) et des hydrogénocarbonates (12,017mg/L). Les concentrations de ces anions indiquent que cette solution est très riche en chlorure qu’aux autres anions trouvés. Par conséquent, le sel de palme est un mélange de sels riche en chlorure de potassium. La quantité de sel végétal obtenue à la préparation contrôlée rapportée à la biomasse végétale est de l’ordre de 1,24% donc assez faible.
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Szuromi, Phil. "CO 2 reduction off base." Science 355, no. 6327 (February 23, 2017): 809.6–810. http://dx.doi.org/10.1126/science.355.6327.809-f.

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Podhorná, Božena, Irena Andršová, Jana Dobrovská, Vlastimil Vodárek, and Karel Hrbáček. "Structure Stability of Ni-Base and Co-Base Alloys." Materials Science Forum 782 (April 2014): 431–36. http://dx.doi.org/10.4028/www.scientific.net/msf.782.431.

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This article summarises results of structure stability investigation of cast Ni-base and Co-base alloys after prolonged high temperature exposure at 900-1100 °C. Cast Ni (Co)-Cr-W-C alloys are resistant to high-temperature corrosion, due to high chromium content. Their heat resistance is caused by presence of carbides, which are stable at very high temperatures. Carbides precipitate in shape of large plate-like particles or carbide eutectics at casting cell boundaries, thus forming carbide skeleton of the alloy. Carbide morphology and temperature stability depends on chemical composition of the alloy, e.g. carbide content, type and content of carbide-forming elements. Microstructure changes were evaluated by stereological analysis and X ray-spectral microanalysis.
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Sahay, S. K., and B. Goswami. "Recent Developments in Co-Base Alloys." Solid State Phenomena 150 (January 2009): 197–219. http://dx.doi.org/10.4028/www.scientific.net/ssp.150.197.

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Cobalt base alloys are being designed and developed to produce the best possible combinations of high temperature properties. Existence of martensite forms consisting of various intermetallic compounds has been described along with the variables associated with fcc-hcp transition at respective conditions of formation. Achievements of cobalt base alloys have been primarily due to various thermodynamic and kinetic parameters for most suitable combinations of alloying. The phase transformations in this review include the study of defect structure, martensite transformation, order-disorder kinetics, and recrystallization and grain growth mechanisms. The improvements in mechanical properties stem from the contribution of additional alloying elements to discontinuous precipitation, diffusion mechanism at grain boundaries and changes in compressive strength, yield strength, elongation and brittleness. L12-compound in cobalt base alloys possesses an important identity, which changes the characteristics of usable compositions.
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Gao, Lisheng, Hanzheng Guo, Shujun Zhang, and Clive Randall. "Base Metal Co-Fired Multilayer Piezoelectrics." Actuators 5, no. 1 (March 1, 2016): 8. http://dx.doi.org/10.3390/act5010008.

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Hougland, Dana, and Kelly Stumpf. "Buckley Air Force Base Chapel CO." Journal of the Acoustical Society of America 119, no. 5 (May 2006): 3371. http://dx.doi.org/10.1121/1.4786547.

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Dissertations / Theses on the topic "Hydroxydes à base de Co"

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Duan, Yan. "Understanding the oxygen evolution reaction (OER) for Co based transition metal oxides / hydroxides in alkaline electrolytes." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS416.

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Le développement d'électrocatalyseurs efficaces pour la réaction de libération d'oxygène (OER) est important pour améliorer l'efficacité globale du processus d'électrolyse de l'eau. Les oxydes / hydroxydes de métaux de transition présentent une activité et une stabilité raisonnables lorsqu’utilisés dans un milieu alcalin. Ils ont le potentiel de remplacer les oxydes à base d'Ir et de Ru. Comprendre la réaction d’OER pour les oxydes / hydroxydes de métaux de transition dans les électrolytes alcalins aide à la conception d'électrocatalyseurs peu coûteux et très efficaces. Avec trois travaux différents sur les oxydes / hydroxydes à base de Co, cette thèse approfondit la compréhension des propriétés de surface des matériaux et des propriétés interfaciales sur la cinétique de la réaction d’OER. Tout d'abord, la substitution au fer régule par exemple la configuration des cations métalliques dans LaCoO3. Cela ajuste la covalence de la liaison oxygène 2p – métal 3d et améliore les performances. Deuxièmement, la substitution au Ni dans ZnCo2O4 modifie la position relative du centre de la bande O 2p et du centre de la bande métallique dans un environnement octahédrique MOh. Cela modifie la stabilité et la possibilité pour l'oxygène du réseau de participer à la réaction de dégagement d’oxygène. Enfin, en étudiant les séries La1-xSrxCoO3, CoOOH et CoOOH contenant Fe, l'impact de l'électrolyte sur les paramètres de la cinétique de réaction a été exploré. Avec une meilleure compréhension de la façon dont les propriétés des matériaux et l'environnement dynamique influencent l'activité et le mécanisme des OER, nous pouvons obtenir des catalyseurs de OER plus efficaces pour une meilleure infrastructure énergétique
The development of efficient electrocatalysts to lower the overpotential of oxygen evolution reaction (OER) is of fundamental importance in improving the overall efficiency of fuel production by water electrolysis. Among a plethora of catalysts being studied on, transition metal oxides / hydroxides that exhibit reasonable activity and stability in alkaline electrolyte have been identified as catalysts to potentially overpass the activity of expensive Ir- and Ru- based oxides. Understanding the OER for transition metal oxides / hydroxides in alkaline electrolytes paves the way for better design of low cost and highly efficient electrocatalysts. This dissertation, with three different work on Co-based oxides / hydroxides, studies and deepens the understanding of the bulk properties, surface properties of materials and interfacial properties on OER. Firstly, with Fe substitution, it addresses tuning the eg configuration of metal cations in LaCoO3 where adjusting the metal 3d oxygen 2p covalency can bring benefits to the OER performance. Secondly, with Ni substitution in ZnCo2O4, it demonstrates a change in relative position of O p-band and MOh d-band centre which induces a change in stability as well as the possibility for lattice oxygen to participate in the OER. Finally, with La1-xSrxCoO3 series, CoOOH and Fe-containing CoOOH as examples, the impact of the electrolyte has been explored by the study of reaction kinetics parameters. With a better understanding of how material properties and dynamic environment influence the OER activity and mechanism, we can obtain more efficient OER catalysts for better energy infrastructure
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Landemaine, Benoît. "Contribution au développement d'un nouveau retardateur de flamme sans halogène à base d'hydroxyde de magnésium." Le Mans, 2001. http://cyberdoc.univ-lemans.fr/theses/2001/2001LEMA1011.pdf.

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Les polymères accroissent les risques d'incendies, du fait de leurs natures inflammables. Ce risque est réduit par ajout de retardateur de flamme (FR). Les FR halogénés présentent l'inconvénient de libérer des fumées opaques et toxiques. La réglementation internationale tente de limiter leur utilisation et favorise le développement de charges nùnérales comme l'hydroxyde de magnésium (MGH) car il dégage peu de gaz toxiques et/ou corrosifs. Le but de ce travail réside dans la caractérisation et l'optimisation de formulations à base de copolymère éthylène-propylène (EPc) et de MGH en terme de tenue au feu et de propriétés mécaniques pour le remplacement des câbles automobile en PVC. Afin d'anticiper les changements législatifs, FL-,%,WMAG a développé une synthèse hydrotherinale de MGH permettant le recyclage d'une partie des réactifs, limitant ainsi, le coût de production et les rejets dans l'environnement. Le remplacement du PVC par des EPc fortement chargés en MGH (60,Vo wlw pour la même tenue au feu) génère une perte des propriétés mécaniques. U modification de surface du MGH par l'ac. Stéarique améliore la compatibilité entre le MGH (polaire) et l'EPc (apolaire) et donc les propriétés mécaniques (tenue aux chocs). L'analyse de surface du MGII enrobé par l'ac. Stéarique montre la présence d'un sel mixte, ce qui montre le caractère réactif de l'enrobage. Les tests au calorimètre à cône montrent une baisse du CO, du C02, du volume de fumée et la diminution de la quantité de chaleur produite par rapport aux MGH références. Dans le cas Flainemag, le MgO issu de la déshydratation du MGH adsorbe le carbone provenant de la décomposition de l'EPc (limitation fumée) mais, contrairement aux autres MGH, ne catalyse pas l'oxydation du carbone, limitant la production de gaz. Les formulations références libèrent donc plus de COIC02 et une quantité de chaleur supplémentaire en raison de l'oxydation exothermique du carbone.
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Muller, Pascal. "Gestion des déchets minéraux industriels : de l'inertage à la valorisation matière : application aux effluents et boues d'hydroxydes à base de fer, zinc et nickel." Metz, 1997. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1997/Muller.Pascal.SMZ9721.pdf.

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La gestion actuelle des effluents liquides contenant des métaux lourds passe par des traitements qui conduisent à l'obtention de boues d'hydroxydes métalliques dont la mise en décharge pose un problème de cout et de capacité d'accueil des sites de stockage. La recherche de nouvelles voies de traitement de ces déchets minéraux, principalement ceux charges en fer et en zinc, doit permettre, par des opérations d'inertage chimique et de valorisation matière, de limiter voir d'éviter la mise en décharge. Leur principe repose sur une sélectivité de la réactivité chimique des espèces métalliques présentes. La première voie envisagée correspond à une recherche de stabilisation chimique sous forme de sulfure insoluble des formes minéralogiques du zinc présents dans les boues d'hydroxydes métalliques en mettant à profit la réactivité de solutions de polysulfures. Le procédé appliqué à des boues synthétiques puis industrielles démontre que le déchet peut être inerte à température ambiante et pour des temps de traitement compatibles avec les impératifs industriels. Un second procédé permet la détoxication du déchet par extraction des éléments polluants et le recyclage des produits obtenus en vue d'une valorisation matière. L'utilisation de ligands minéraux comme les thiosulfates et de ligands organiques de la famille des polyéthylène-polyamines permet l'obtention de réactifs lixiviants conjuguant effet de pH et de complexation. La solubilité importante des formes ZnO et Zn(OH)2 dans ces milieux permet d'envisager un traitement similaire sur les boues d'hydroxydes. Une étude cinétique de la lixiviation montre qu'il est possible d'extraire dans des conditions économiques et technologiques acceptables la quasi-totalité du zinc présent dans le solide sans entrainement de fer. La dernière voie étudiée propose de mener des opérations de précipitation sélective des cations métalliques présents dans l'effluent, en amont des traitements physico-chimiques classiques. Les propriétés oxydoréductrices et sulfurantes des polysulfures permettent de précipiter, dans des solutions mixtes de fer-zinc-nickel, le sulfure de zinc ou de nickel sans entrainer la précipitation du fer. Ce type de protocole appliqué à des effluents industriels conduit à la récupération des sulfures des métaux lourds avant la précipitation des hydroxydes de fer. Les résidus sulfures ainsi que les hydroxydes de fer pourraient être réorientés vers des filières de valorisation ou de recyclage
The treatment process of liquid waste containing heavy metals by metal hydroxyde precipitation is the most commonly employed. At the present time, the sludge are an ultimate waste wich are stored in landfilling. In a first time, the objective is the inertizing of heavy metal like zinc. The principle of transformation of leaching forms containing heavy metal in metallic sulfides slightly soluble appears like a way to explore. The present work confirms that a sulfurization of mineralogic form of zinc containing in sludge is faisable from polysulfides solutions. The performance of this process is confirmed in the case of real sample stemming from industry. In a second time, we studied the possibility of the selective extraction method by leaching of zinc-bearing phases. Chemical leaching of ZnO and Zn(OH)2 with a solution of inorganic ligand as thiosulphate and organic ligand such as polyethylene-polyamine appeared to be an efficient method. This detoxication method has been validated using these reagents on the real hydroxyde sludge stemming from industry. The result confirms that this treatment led to the extraction of the potential polluting zinc fraction contained in the waste. The last method studied the possibility of selective precipitation of heavy metal contained in liquid waste before classical physicochemical treatment. The reducing power of polysulfides and the formation possibility of metallic sulfides slighthly soluble bring about the selective precipitation of zinc sulfide and nickel in mixte solution of fer-zinc-nickel. The treatment of liquid waste containing heavy metal is possible. The final-products are a sulfur-metallic sulfur heavy metal mixture and an hydroxie ferric cake. The use of this products as new materials in different industries is actually under study
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Ribet, Solange. "Propriétés catalytiques d'hydroxydes doubles lamellaires multicomposants (Co, Ni, Mg, Al). Application à l'hydrogénation de l'acétonitrile." Montpellier 2, 1999. http://www.theses.fr/1999MON20051.

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Des hydroxydes doubles lamellaires (hdl) multicomposants, contenant les cations co 2 +, ni 2 +, mg 2 + et al 3 +, obtenus par coprecipitation a ph constant, en controlant les parametres de synthese, ont ete utilises comme precurseurs de catalyseurs d'hydrogenation. L'etude de l'activation montre que les stabilites thermiques des echantillons sont fonction de leur teneur en magnesium et de leur densite de charge dans les feuillets. Les phases cristallines obtenues apres calcination sont un melange de phases oxydes mixtes et spinelles. Les reductibilites dependent largement de leur composition. De ce fait, le cobalt se reduit dans deux types d'especes bien identifiables, alors que le profil de reduction attribuable au nickel traduit une plus large distribution d'especes. Les proprietes acido-basiques et metalliques des catalyseurs sont reliees a leurs activite dans l'hydrogenation de l'acetonitrile. Ils presentent une selectivite elevee pour la formation de l'amine primaire, et permettent dans le meilleur des cas d'atteindre 96% d'ethylamine a 98% de conversion. L'etude comparative des divers solides ne met en evidence aucune correlation nette entre leur acido-basicite et la selectivite. Par contre, l'association du nickel et du cobalt induit un effet de synergie, attribue a une dilution des ensembles nickel par le cobalt, ce qui limite la formation des produits secondaires de condensation.
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Touati, Souad. "Elaboration d'aérogels d'hydroxydes doubles lamellaires et de bionanocomposites à base d'alginate." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00975932.

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Cette thèse présente un travail sur l'obtention d'aérogels d'HDL par séchage en conditions CO2 supercritique et l'élaboration de nouveaux bionanocomposites formés par la coprécipitation d'hydroxydes doubles lamellaire (HDL) dans l'espace confiné des billes d'alginate. Grâce à la combinaison d'une synthèse par coprécipitation Flash et d'un séchage en conditions supercritiques au CO2, des aérogels d'HDL possédant des surfaces spécifiques élevées sont élaborés. Parallèlement, l'alginate est utilisé comme une matrice de confinement pour la précipitation inorganique d'HDL. D'une part, les billes d'alginate sont synthétisées par complexation des ions Ca2+ et la coprécipitation des phases HDL s'effectue en réalisant des imprégnations successives de réactifs. D'autre part, des billes d'alginate sont formées directement en présence des cations divalents (Mg2+, Ni2++, Co2+, ...) et des cations des métaux trivalents (Al3+), précurseurs des composés inorganiques. La coprécipitation des HDL se produit dans ce cas lors d'une étape d'imprégnation dans une solution d'hydroxyde de sodium. Tous les composés HDL, aérogels ou encore bionanocomposites sont caractérisés en détail par DRX, spectroscopie IR, MEB/MET, adsorption/désorption d'azote et ATG/DTG, pour obtenir un meilleur aperçu de la structure des particules, de leur taille et de leur morphologie. Des études menées sur l'adsorption de la trypsine pour les aérogels ou encore sur les performances d'électrodes modifiées HDL-alginate ont permis de montrer qu'il était possible d'améliorer les performances des HDL en augmenter leur porosité et en élaborant des bionanocomposites.
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Carli, Larissa Nardini. "Nanocompósitios poliméricos biodegradáveis à base de poli(hidroxibutirato-co-hidroxivalerato)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/61256.

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O objetivo deste trabalho foi a obtenção de nanocompósitos de poli(hidroxibutirato-co-hidroxivalerato) (PHBV) com diferentes filossilicatos – montmorilonita (OMMT) e haloisita (HNT), na proporção de 1, 3 e 5% em massa, através de processamento no estado fundido. A influência do tipo e teor de nanopartícula, das condições de processamento e da modificação com organosilanos sobre a morfologia e propriedades térmicas e mecânicas dos nanocompósitos foi avaliada. A cristalização dos nanocompósitos apresentou dependência no tipo de nanopartícula: a OMMT dificultou a formação dos esferulitos, enquanto que a HNT promoveu a formação de estruturas mais regulares e orientadas, com maior temperatura de fusão. Os nanocompósitos preparados com teores mais elevados de nanopartículas e em maior intensidade de cisalhamento apresentaram melhor dispersão, o que foi refletido em um aumento nas propriedades mecânicas e de barreira. As nanopartículas modificadas apresentaram diferentes resultados, dependendo do grau de interação do grupo funcional com o polímero. Interações mais fracas promoveram aumento na ductilidade e tenacidade dos nanocompósitos. Por outro lado, a degradação da matriz na presença de sais de amônio quaternário ou de aminosilanos influenciou negativamente o desempenho térmico e mecânico dos nanocompósitos. O conjunto de resultados revelou o potencial da haloisita comparada à montmorilonita. Os nanocompósitos com HNT não modificada apresentaram melhores características de processamento e balanço de propriedades, com aumento no alongamento na ruptura e resistência ao impacto, mantendo elevada rigidez, além de uma diminuição de 93% nos valores de permeabilidade ao oxigênio.
In this work, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposites were prepared by melt intercalation process using 1, 3 and 5 wt% of different phyllosilicates – montmorillonite (OMMT) and halloysite (HNT). The effect of the clay type and content, as well as the processing conditions and the modification with organosilanes on the morphology and thermal and mechanical properties of the nanocomposites were evaluated. The crystallization characteristics of the nanocomposites were dependent on the clay type: OMMT prevented the formation of the spherulites, while HNT promoted the formation of a regular and oriented structure with higher melting temperature. The nanocomposites prepared with high clay content and high shear intensity presented a better dispersion, which resulted in an improvement in the mechanical properties and barrier property. The modified nanoparticles presented different results, depending on its degree of interaction with the polymer matrix. For weak interactions, it was observed an increase in ductility and toughness of the nanocomposites. The degradation of the polymer matrix in the presence of aminosilanes or quaternary ammonium salts negatively influenced the thermal and mechanical performance of the nanocomposites. The set of results revealed the potential of halloysite in comparison to montmorillonite. The nanocomposites with unmodified HNT presented the best set of properties, with improved processing characteristics, strain at break and impact strength while maintaining a high stiffness, and a reduction of 93% in the oxygen permeability.
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Погребняк, Олександр Дмитрович, Александр Дмитриевич Погребняк, Oleksandr Dmytrovych Pohrebniak, Ігор Анатолійович Кулик, Игорь Анатольевич Кулик, Ihor Anatoliiovych Kulyk, V. M. Rogoz, et al. "Phase composition and physical properties of Co-Cr base coating." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20651.

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Coating structure was mainly composed of α-fcp- and β-fcc-cobalt. Selected temperature interval for coating formation, according to XRD analysis, allowed us to form inter-metalloid compounds of CoxCry-type cobalt with chromium. Subsequent melting of a surface layer by a plasma jet resulted to doping of the coating surface by Mo atoms (compounds) from doping electrodes. It was demonstrated that essential improvement of servicing characteristics was due phase transformations induced by high-temperature plasma jet, Mo doping, redistribution of elements in the coating, and appearance of micro- and nano-grained structure, as well as decreasing porosity due to repeated melting. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20651
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Djebbi, Mohamed Amine. "Les Hydroxydes Doubles Lamellaires au coeur de la biotechnologie : évaluation des applications médicales et environnementales." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1049/document.

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Les matériaux hydroxydes doubles lamellaires (HDL) sont une classe d'argiles anioniques synthétiques dont la structure est basée sur celle du brucite Mg(OH)2 dans lesquelles une partie des cations métalliques divalents sont été remplacés par des ions trivalents donnant ainsi des feuillets chargés positive. Cette charge est équilibrée par l'intercalation d'anions dans la région interlamellaire hydratée. Les identités et les rapports des cations di- et trivalents et l'anion interlamellaire peuvent être varié sur une large gamme, donnant lieu à une large classe de matériaux isostructurales. Le matériau d’origine de cette classe est l’hydrotalcite (HT) et les HDL sont par conséquent également connus comme des matériaux de type hydrotalcite. Bien que les caractéristiques de base de la structure soient bien comprises, des aspects structurels détaillés ont fait l'objet de certaine controverse dans la littérature afin de maîtriser leurs propriétés et leurs applications potentielles. Dans ce travail de thèse nous avons retenu deux types de HDL MgAl et ZnAl qui ont été largement introduits dans diverses applications, tels que la sorption des molécules d'intérêt biologique (enzyme et médicament) et l'élaboration d'électrodes. La spécificité de ce travail repose sur l’immobilisation d’une enzyme modèle, la lactate déshydrogénase dans ces deux matrices ainsi qu’un médicament anti-bactérien, la berbérine, afin d’étudier les interactions entre ces deux biomolécules et la phase HDL introduite et de répondre à leurs exigences d'applications dans le domaine médical. Dans un second temps nous avons tenté d’étudier les deux phases mentionnées de plus en plus fine en termes de structure, morphologie et profil électrochimique en vue de les employer en tant que matériaux d’électrode pour le développement de biopile
DHs are a class of synthetic anionic clays whose structure is based on brucite-like layers Mg(OH)2 inwhich some of the divalent cations have been replaced by trivalent ions giving positively-charged sheets.This charge is balanced by intercalation of anions in the hydrated interlayer regions. The identities andratios of the di- and trivalent cations and the interlayer anion may be varied over a wide range, giving rise toa large class of isostructural materials. The parent material of this class is the naturally occurring mineralhydrotalcite and LDHs are consequently also known as hydrotalcite-like materials. Although the basicfeatures of the structure are well understood, detailed structural aspects have been the subject of somecontroversy in the literature. In this thesis, we have selected two types of LDH, MgAl and ZnAl, which havebeen widely introduced in various applications, such as sorption of molecules of biological interest (enzymeand drug) and the development of electrodes. The specificity of this work lies on the immobilization of amodel enzyme, lactate dehydrogenase in both matrices as well as an anti-bacterial drug, berberine, inorder to study the interactions between these two biomolecules and the introduced LDH phase and tobetter address their challenges of applications in the medical field. Second, we have tried to study the twophases mentioned above more and more accurately in terms of structure, morphology and electrochemicalprofile in order to use them as electrode materials for microbial fuel cell device
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Morale, Francesca. "Metallomesogens derived from Schiff-base chelates and related co-ordination chemistry." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269486.

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Daix, Nicolas. "Mécanismes de base dans la co-implantation hélium - hydrogène du silicium." Toulouse 3, 2009. http://www.theses.fr/2009TOU30238.

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Parmi les matériaux de base utilisés en microélectronique, le SOI (silicium sur isolant), fabriqué par la technologie Smart CutTM, a réussi à tirer son épingle du jeu. Cette technologie enchaîne plusieurs étapes clés, dont l'une est l'implantation ionique d'hydrogène. Pour des raisons économiques, l'utilisation d'hydrogène à forte dose a été remplacée par une co-implantation hélium / hydrogène. La co-implantation est un " système " complexe, récent et donc relativement peu compris. Nous avons proposé un scénario décrivant la transformation des platelets en microfissures puis en onde de fracture. Les populations de défauts croissent en moyenne selon un mûrissement d'Ostwald, mais une faible partie des défauts interagit par coalescence. Nous avons trouvé un critère d'interaction basé sur la taille des défauts et la distance les séparant. Nous avons testé et validé la spectroscopie Raman comme technique permettant d'identifier les complexes hydrogénés mis en jeu après implantation et en cours de recuit. Nous avons ainsi pu vérifier l'étape de nucléation des platelets dans plusieurs conditions d'implantation. Nous avons montré que la redistribution de l'hélium est essentiellement due à la diffusion et au piégeage de l'hélium sur les platelets générées par l'implantation d'hydrogène, à l'aide d'un modèle physique simple. La réduction de dose spectaculaire de la co-implantation par rapport à l'implantation standard d'hydrogène provient majoritairement du fait que l'hélium est un gaz monoatomique, contrairement au dihydrogène. Nous avons également montré que le retard sur les cinétiques de fracture avec l'ordre d'implantation inversé est un effet purement balistique
Among the different substrates used in the microelectronic industry, the SOI (Silicon On Insulator), manufactured by Smart CutTM technology, is used more and more. This technology involves several process steps, one of which is the ion implantation of hydrogen. For cost-effective reasons, the co-implantation of helium / hydrogen has replaced the hydrogen only step. The co-implantation is a " complex " and recent system and it is not well understood. We have suggested a global picture that describes the defect formation process: some of the platelets are transformed into microcracks and then result in fracture wave. Both populations of defects evolve in average following an Ostwald ripening, but few of the defects interact by coalescence. We have found a criterion of interaction based on the size of the defects and the distance between them. We have tested and approved the Raman spectroscopy as a technique allowing the identification of the hydrogenated complexes playing a role after implant and during the annealing. We have then checked the nucleation step of platelets for several implantation conditions. We have shown that the helium redistribution is mainly due to diffusion and gettering of helium on hydrogenated platelets, thanks to a simple physical model. The drastic dose reduction in co-implantation as compared to hydrogen only case, comes mainly from the fact that helium is a monatomic gas, as oppose to hydrogen gas. We have also shown that the delay in fracture kinetics with the reverse order of implantation is a pure ballistic effect
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Books on the topic "Hydroxydes à base de Co"

1

Aspen, Harald. Competition and co-operation: North Ethiopian peasant households and their resource base. Trondheim: UNIT Centre for Environment and Development, 1993.

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Ramesh, B. R. Biotik: Biodiversity informatics and co-operation in taxonomy for interactive shared knowledge base. Pondicherry: Institut français de Pondichéry, 2010.

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Varley, Rita. The government household transfer data base, 1960-1984. Paris, France: OECD, Dept. of Economics and Statistics, 1986.

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Varley, Rita. The government household transfer data base, 1960-1984. [Paris]: Organisation for Economic Co-operation and Development, 1986.

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Statistics, Organisation for Economic Co-operation and Development Dept of Economics and. An international sectoral data base for thirteen OECD countries. Paris: OECD, 1988.

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M, Wheeler R., and United States. National Aeronautics and Space Administration., eds. A data base of nutrient use, water use, CO₂ exchange, and ethylene production by soybeans in a controlled environment. [Washington, D.C: National Aeronautics and Space Administration, 1998.

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United States. National Aeronautics and Space Administration., ed. 10,000-hour cyclic oxidation behavior at 982 C (1800 F) of 68 high-temperature Co, Fe-, and Ni-base alloys. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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United States. National Aeronautics and Space Administration., ed. 10,000-hour cyclic oxidation behavior at 982 C (1800 F) of 68 high-temperature Co, Fe-, and Ni-base alloys. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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United States. National Aeronautics and Space Administration., ed. 10,000-hour cyclic oxidation behavior at 982 C (1800 F) of 68 high-temperature Co, Fe-, and Ni-base alloys. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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A, Barrett Charles, and United States. National Aeronautics and Space Administration., eds. The effect of Cr, Co, Al, Mo, and Ta on a series of cast Ni-base superalloys on the stability of an aluminide coating during cyclic oxidation in Mach 0.3 burner rig. [Washington, D.C.]: National Aeronautics and Space Administration, 1986.

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Book chapters on the topic "Hydroxydes à base de Co"

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Robinson, Tim, David White, and Ross Grassi. "Acid Mist Abatement in Base Metal Electrowinning." In Ni-Co 2013, 143–53. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-48147-0_9.

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Robinson, Tim, David White, and Ross Grassi. "Acid Mist Abatement in Base Metal Electrowinning." In Ni-Co 2013, 141–53. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118658826.ch9.

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Eherer, Stefan, and Matthias Jarke. "Knowledge Base Support for Hypermedia Co-Authoring." In Database and Expert Systems Applications, 465–70. Vienna: Springer Vienna, 1991. http://dx.doi.org/10.1007/978-3-7091-7555-2_78.

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Wilson, Douglas Clyde. "Fisheries Co-Management and the Knowledge Base for Management Decisions." In The Fisheries Co-management Experience, 265–79. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-3323-6_16.

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Kerr, Carolyn L. "Perioperative Fluid, Electrolyte, and Acid-Base Disorders." In Canine and Feline Anesthesia and Co-Existing Disease, 129–50. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118834305.ch7.

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Chatterjee, M., A. Pani Kishore, P. Sarkar, and M. Narayana Rao. "Effect of Processing Conditions on Structure, Properties and Performance of a Nickel Base Cast Superalloy for High Temperature Applications." In Ni-Co 2013, 357–63. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-48147-0_28.

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Chatterjee, M., A. Pani Kishore, P. Sarkar, and M. Narayana Rao. "Effect of Processing Conditions on Structure, Properties and Performance of a Nickel Base Cast Superalloy for High Temperature Applications." In Ni-Co 2013, 357–63. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118658826.ch28.

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Black, Jonathan. "In vivo Corrosion of a Cobalt-Base Alloy and Its Biological Consequences." In Biocompatibility of Co-Cr-Ni Alloys, 83–100. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0757-0_8.

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Volz, N., C. H. Zenk, T. Halvaci, K. Matuszewska, S. Neumeier, and M. Göken. "Castability and Recrystallization Behavior of γ′-Strengthened Co-Base Superalloys." In Superalloys 2020, 901–8. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-51834-9_88.

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Hammerschmidt, T., J. Koßmann, C. H. Zenk, S. Neumeier, M. Göken, I. Lopez-Galilea, L. Mujica Roncery, et al. "The Role of Local Chemical Composition for TCP Phase Precipitation in Ni-Base and Co-Base Superalloys." In Superalloys 2016, 89–96. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119075646.ch10.

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Conference papers on the topic "Hydroxydes à base de Co"

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AFOLABI, Akindele Segun, Chikara OHTA, and Hisashi TAMAKI. "A Base Station Co-operation Protocol for Indoor Base Stations." In Annual International Conference on Advances in Distributed and Parallel Computing ADPC 2010. Global Science and Technology Forum, 2010. http://dx.doi.org/10.5176/978-981-08-7656-2_ntc2010-30.

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Cao, Xiaochun, Yupeng Cheng, Zhiqiang Tao, and Huazhu Fu. "Co-Saliency Detection via Base Reconstruction." In MM '14: 2014 ACM Multimedia Conference. New York, NY, USA: ACM, 2014. http://dx.doi.org/10.1145/2647868.2655007.

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Liao, W. B., and Y. Zhang. "Processing and properties of Cu-base and Co-base amorphous wires." In High Density Packaging (ICEPT-HDP). IEEE, 2009. http://dx.doi.org/10.1109/icept.2009.5270553.

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Jerković, Sanja, and Nives Škreblin. "BASE EARTHQUAKE." In 1st Croatian Conference on Earthquake Engineering. University of Zagreb Faculty of Civil Engineering, 2021. http://dx.doi.org/10.5592/co/1crocee.2021.277.

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Gupta, Parul, Arun Vishwanath, Shivkumar Kalyanaraman, and Yong Hua Lin. "Unlocking wireless performance with co-operation in co-located base station pools." In 2010 Second International Conference on COMmunication Systems and NETworks (COMSNETS 2010). IEEE, 2010. http://dx.doi.org/10.1109/comsnets.2010.5431996.

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Song, Shuangyong, Qingliang Miao, Zhiwei Shi, Yao Meng, and Haiqing Chen. "Co-occurrence semantic knowledge base construction for abbreviation disambiguation." In 2017 International Conference on Asian Language Processing (IALP). IEEE, 2017. http://dx.doi.org/10.1109/ialp.2017.8300609.

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Deng, Kai, Jianjiang Zhou, and ZhiWei Zhou. "Multitarget detection for single-base co-prime MIMO radar." In Fifteenth International Conference on Signal Processing Systems (ICSPS 2023), edited by Zhenkai Zhang and Cheng Li. SPIE, 2024. http://dx.doi.org/10.1117/12.3023181.

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Ping, D. H., C. Y. Cui, Y. F. Gu, and H. Harada. "Microstructural Evolution of a Newly Developed ¿' Strengthened Co-base Superalloy." In 2006 19th International Vacuum Nanoelectronics Conference. IEEE, 2006. http://dx.doi.org/10.1109/ivnc.2006.335302.

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Ishida, K. "RECENT PROGRESS ON CO-BASE ALLOYS: PHASE DIAGRAMS AND APPLICATION." In 62º Congresso anual da ABM. São Paulo: Editora Blucher, 2007. http://dx.doi.org/10.5151/2594-5327-0485.

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Govender, Preyin, Deborah Clare Blaine, and Natasha Sacks. "Influence Of Base Plate Coating On LPBF Of WC-Co." In World Powder Metallurgy 2022 Congress & Exhibition. EPMA, 2022. http://dx.doi.org/10.59499/wp225371527.

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While additive manufacturing (AM) is rapidly gaining ground as an established manufacturing process for many industries, understanding and controlling process parameters in order to develop validated process chains remains an area for research and development. A critical parameter that is relevant to laser powder bed fusion (LPBF), the most widely used metal AM technology, is baseplate material selection. This is especially relevant for uncommon build materials such as cemented carbides. In this study, LPBF of WC-Co cemented carbides is investigated, evaluating the influence of baseplate coating on the build. A DIN 1.2343 tool steel baseplate was used for WC-Co LPBF builds, both in the uncoated and coated state. WC-CoCr (1350VM) powder was used to coat the baseplate, while two WC-Co powders with different Co content (17 and 12 wt%, respectively) were used to compare builds of these alloys. The WC-Co powders were characterized to establish their suitability for LPBF. Cuboids were printed, with and without supports, on the coated and uncoated baseplates. Low density builds were built (~88% dense) relating to poor printing parameters. Evaporation of Co is present, yet WC-17Co samples on supports showed little evaporation and good build volume.
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Reports on the topic "Hydroxydes à base de Co"

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ME Petrichek. Experimental Design for Evaluation of Co-extruded Refractory Metal/Nickel Base Superalloy Joints. Office of Scientific and Technical Information (OSTI), December 2005. http://dx.doi.org/10.2172/884672.

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Mallon, B., D. Layton, R. Fish, P. Hsieh, L. Hall, L. Perry, and G. Snyder. Conventional weapons demilitarization: A health and environmental effects data base assessment: Propellants and their co-contaminants. Office of Scientific and Technical Information (OSTI), August 1988. http://dx.doi.org/10.2172/5873712.

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Young, Allison, Carey Baxter, Joseph Murphey, Karlee Feinen, Madison Story, and Adam Smith. US Air Force Academy Gallagher and Massey ranch houses : Historic American Buildings Surveys CO-237, CO-237-A, and CO-238. Engineer Research and Development Center (U.S.), June 2023. http://dx.doi.org/10.21079/11681/47190.

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The US Congress codified the National Historic Preservation Act of 1966 (NHPA), the nation’s most effective cultural resources legislation to date, mostly through establishing the National Register of Historic Places (NRHP). The NHPA requires federal agencies to address their cultural resources, which are defined as any prehistoric or historic district, site, building, structure, or object. Section 110 of the NHPA requires federal agencies to inventory and evaluate their cultural resources, and Section 106 requires them to determine the effect of federal undertakings on those potentially eligible for the NRHP. The US Air Force Academy is located at the base of the Front Range within El Paso County. The US Air Force Academy has been used for training US Air Force officers since 1954. The Gallagher Ranch House and its associated garage, erected circa 1953, and the Massey Ranch House, erected 1941, are eligible for the National Register of Historic Places. This report documents the buildings to the standards of the Historic American Buildings Survey and includes a historic context, architectural descriptions, photographs, and measured drawings. This report satisfies Sections 106 and 110 of the National Historic Preservation Act of 1966 as amended and will be used by the US Air Force Academy for mitigation, allowing for the demolition of the three buildings.
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Tomova, Zlatina, Angelina Vlahova, Christo Kissov, Rada Kazakova, and Dimitar D. Radev. Corrosion Resistance and Biocompatibility of Multicomponent Ni- and Co ‑ Base Dental Alloys Obtained by Methods of Powder Metallurgy. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, July 2018. http://dx.doi.org/10.7546/crabs.2018.07.05.

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Chepeliev, Maksym. Development of the Air Pollution Database for the GTAP 10A Data Base. GTAP Research Memoranda, June 2020. http://dx.doi.org/10.21642/gtap.rm33.

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The purpose of this note is to document data sources and steps used to develop the air pollution database for the GTAP Data Base Version 10A. Emissions for nine substances are reported in the database: black carbon (BC), carbon monoxide (CO), ammonia (NH3), non-methane volatile organic compounds (NMVOC), nitrogen oxides (NOx), organic carbon (OC), particulate matter 10 (PM10), particulate matter 2.5 (PM2.5) and sulfur dioxide (SO2). The dataset covers four reference years – 2004, 2007, 2011 and 2014. EDGAR Version 5.0 database is used as the main data source. To assist with emissions redistribution across consumption-based sources, IIASA GAINS-based model and IPCC-derived emission factors are applied. Each emission flow is associated with one of the four sets of emission drivers: output by industries, endowment by industries, input use by industries and household consumption. In addition, emissions from land use activities (biomass burning) are estimated by land cover types. These emissions are reported separately without association with emission drivers.
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Page, Kelly, Alexandra Merritt Johnson, Kristen Franklin, Bria Carter, Marilys Galindo, Teresa Solorzano, Sangyeon Lee, and Zohal Shah. Principios de Aprendizaje de la Transición de Diseño para los Expedientes de Aprendizaje y Empleo: Co-diseño para la Equidad. Digital Promise, July 2023. http://dx.doi.org/10.51388/20.500.12265/186.

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Las tecnologías emergentes, como los registros de aprendizaje y empleo (LER), se han identificado como una solución prometedora para que los alumnos y trabajadores histórica y sistemáticamente excluidos (HSE) compartan y accedan a sus datos de aprendizaje y competencias a partir de sus itinerarios de aprendizaje y transiciones individuales. Sin embargo, los itinerarios de aprendizaje rara vez son lineales; la forma en que los alumnos y los trabajadores pueden demostrar y obtener reconocimiento por sus habilidades y competencias puede evolucionar con el tiempo. Además, las barreras sistémicas y las desigualdades arraigadas en los itinerarios de aprendizaje de las comunidades de HSE afectan de manera desproporcionada a su capacidad para acceder y persistir en el ecosistema educativo y laboral. Es fundamental que los LER se diseñen de forma accesible y equitativa para las comunidades de HSE a fin de mitigar las desigualdades sistémicas y estructurales en el ecosistema educativo y laboral. Con el generoso apoyo de la Fundación Bill y Melinda Gates, Digital Promise colaboró con alumnos adultos y trabajadores de la ESS para establecer un conjunto de principios de diseño que sirvieran de base para el desarrollo de tecnologías de REA para su uso a lo largo de la trayectoria profesional y de aprendizaje de las personas, incluidas sus transiciones de aprendizaje. Mediante entrevistas individuales y talleres de grupo con alumnos adultos y trabajadores de la HSE, se han identificado los principios de diseño clave para influir en la infraestructura de datos LER desde la educación hasta la fuerza laboral.
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Price, Roz. Nature-based Solutions (NbS) – What are They and What are the Barriers and Enablers to Their Use? Institute of Development Studies (IDS), May 2021. http://dx.doi.org/10.19088/k4d.2021.098.

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This rapid review examines literature around Nature-based Solutions (NbS), what are NbS, the pros and cons of NbS, design and implementation issues (including governance, indigenous knowledge), finance and the enabling environment. The breadth of NbS and the evidence base means that this rapid review only provides a snapshot of the information available, and therefore does not consider all types of NbS, nor all sectors that they have been used in. Considering this limited scope, this report highlights many issues, some of which are that Covid-19 has highlighted the importance of NbS, Pros of NbS include the low cost compared to infrastructure alternatives; the flexibility in addressing multiple climate challenges; potential co-benefits such as better water quality, improved health, cultural benefits, biodiversity conservation. The literature also notes the cons of NbS including slow adaptation or co-benefits, very context specific making effectiveness difficult to measure and many of the benefits are non-monetary and hard to measure. The literature consulted suggest a number of knowledge gaps in the evidence base for NbS effectiveness including lack of: robust and impartial assessments of current NbS experiences; site specific knowledge of field deployment of NbS; timescales over which benefits are seen and experienced; cost-effectiveness of interventions compared to or in conjunction with alternative solutions; and integrated assessments considering broader social and ecological outcomes
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Olsen. PR-179-10203-R01 Characterization of Oxidation Catalyst Performance - VOCs and Temperature Variation. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), June 2012. http://dx.doi.org/10.55274/r0010753.

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Oxidation catalysts are typically specified to reduce carbon monoxide (CO), Hazardous Air Pollutants (HAPs) and/or Volatile Organic Compounds (VOCs) from lean-burn engines. The application of catalysts to HAPs and VOC destruction is more recent, so greater effort has been placed on optimizing for CO oxidation than HAPs or VOC oxidation. In general, the catalysts consist of a porous, high surface area -alumina carrier material on a ceramic (typically cordierite) or stainless steel substrate. Although the alumina has some effectiveness in oxidation at high temperature, its primary role here is to provide a high surface area support for a well dispersed layer of platinum (Pt) and/or palladium (Pd) which provides numerous catalytic sites for oxidation activity. This work extends the current knowledge-base for application of oxidation catalysts in three areas: (1) species specific removal efficiencies, (2) temperature dependence, and (3) space velocity.
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Güemes, Cecilia. Experiencia como fuente de solidaridad: los espacios públicos de socialización informal. Fundación Carolina, January 2024. http://dx.doi.org/10.33960/ac_01.2024.

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Un nuevo contrato social requiere activar compromisos solidarios y, para ello, resulta clave contar con imaginarios de co-implicación que surjan de la experiencia y vivencia del otro. En vez de elaborar una argumentación de base moral abstracta que mueva las conciencias, o centrar los esfuerzos en desarrollar una visión sobre el contrato social, este trabajo se focaliza en la generación de sentidos de responsabilidad común desde la convivencia y encuentro en espacios públicos de socialización informal. A tales fines, explora las razones que justifican una revisión del foco de análisis, del mundo de las razones morales al de las experiencias concretas, así como las coyunturas adversas que toca enfrentar en América Latina para fortalecer tales espacios.
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Kamrath, Matthew, Vladimir Ostashev, D. Wilson, Michael White, Carl Hart, and Anthony Finn. Vertical and slanted sound propagation in the near-ground atmosphere : amplitude and phase fluctuations. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40680.

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Sound propagation along vertical and slanted paths through the near-ground atmosphere impacts detection and localization of low-altitude sound sources, such as small unmanned aerial vehicles, from ground-based microphone arrays. This article experimentally investigates the amplitude and phase fluctuations of acoustic signals propagating along such paths. The experiment involved nine microphones on three horizontal booms mounted at different heights to a 135-m meteorological tower at the National Wind Technology Center (Boulder, CO). A ground-based loudspeaker was placed at the base of the tower for vertical propagation or 56m from the base of the tower for slanted propagation. Phasor scatterplots qualitatively characterize the amplitude and phase fluctuations of the received signals during different meteorological regimes. The measurements are also compared to a theory describing the log-amplitude and phase variances based on the spectrum of shear and buoyancy driven turbulence near the ground. Generally, the theory correctly predicts the measured log-amplitude variances, which are affected primarily by small-scale, isotropic turbulent eddies. However, the theory overpredicts the measured phase variances, which are affected primarily by large-scale, anisotropic, buoyantly driven eddies. Ground blocking of these large eddies likely explains the overprediction.
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