Academic literature on the topic 'Zones de flux de voyageurs'
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Journal articles on the topic "Zones de flux de voyageurs"
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Pereira, Denis Biolkino de Sousa, and William Rodrigues Ferreira. "REFLEXOS DAS OCUPAÇÕES URBANAS NA MOBILIDADE ÀS MARGENS DA RODOVIA ESTADUAL GO-060 ENTRE GOIÂNIA (GO) E TRINDADE (GO)." Revista Cerrados 18, no. 01 (May 19, 2020): 189–219. http://dx.doi.org/10.22238/rc2448269220201801189219.
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O estudo pretende compreender a dinâmica dos diversos tipos de ocupações implantadas no entorno da Rodovia Estadual GO- 060, entre a cidade de Goiânia (GO) e Trindade (GO), e os seus reflexos na mobilidade urbana. O problema se identifica na relação causa e efeito no conflito entre o espaço urbano e o sistema de transportes, em áreas conurbadas da Região Metropolitana de Goiânia (GO). O objetivo consiste em analisar as áreas de ocupação do recorte espacial, o fluxo veicular dos modos de transportes e o índice de mobilidade, em função das tipologias de ocupação, caracterizadas como polos geradores de viagens (PGVs). Para se identificar tais ocorrências, foram utilizadas metodologias adaptadas para análise espaço-temporal e redes. Os resultados mostraram as diferenças em áreas de ocupação nos PGVs Tipo Comércio/Indústria 25,74% e 30,77% e Tipo Residencial 11,41% e 38,78% para as Regiões Oeste/Mendanha e Trindade 2, para os períodos (2011/2016) e (2009/2015), respectivamente. Essa dinâmica ocupacional gerou um aumento de +87% no total de viagens do fluxo dos diversos modos de transporte e um acréscimo de +79% no índice de mobilidade para o período de 2013 a 2016, mostrando a tendência de motorização das regiões e os reflexos na mobilidade urbana.
Palavras-chave: Ocupação espacial. Sistema viário. Fluxo veicular. Transporte. Mobilidade.
REFLEXES OF URBAN OCCUPATIONS ON MOBILITY TO THE MARGINS OF THE STATE ROAD GO-060 BETWEEN GOIÂNIA (GO) AND TRINDADE (GO)
ABSTRACT
The study aims to understand the dynamics of the various types of occupations implanted around the State Highway GO-060, between the city of Goiânia (GO) and Trindade (GO), and their reflexes on urban mobility. The problem is identified in the cause and effect relationship in the conflict between urban space and the transport system in conurbated areas of the Metropolitan Region of Goiânia (GO). The objective is to analyze the areas of occupation of the spatial area, the vehicular flow of the modes of transport and the mobility index, according to the types of occupation, characterized as travel generating poles (TGPs). To identify such occurrences, methodologies adapted for spatiotemporal analysis and networks were used. The results showed the differences in occupation areas in the Trade / Industry Type 25.74% and 30.77% and Residential Type 11.41% and 38.78% for the West / Mendanha and Trindade 2 Regions for the periods (2011/2016) and (2009/2015) respectively. This occupational dynamic generated an increase of + 87% in the total travel flow of the different modes of transport and an increase of + 79% in the mobility index for the period from 2013 to 2016, showing the trend of motorization in the regions and the reflexes in urban mobility.
Keywords: Spatial occupation. Road system. Vehicular flow. Transport. Mobility.
REFLETS DES OCCUPATIONS URBAINES SUR LA MOBILITÉ LE LONG DE LA ROUTE D’ÉTAT GO-60 ENTRE GOIANIA (GO) ET TRINDADE (GO)
RÉSUMÉ
L’étude prétend comprendre la dynamique des divers types d’occupations implantées le long de la Route d’État GO-060, entre les villes de Goiânia (GO) et Trindade (GO), et ses retombées sur la mobilité urbaine. Le problème s’identifie dans la relation de cause à effet dans le conflit entre espace urbain et système de transport, dans les aires urbanisées de la Région Métropolitaine de Goiânia (GO). L’objectif est d’analyser les zones d’occupation du découpage spatial, le flux routier des modes de transport et l’indice de mobilité selon les typologies d’occupation, caractérisées comme pôles générateurs de voyages (PGVs). L’identification de ces faits s’est réalisée par l’utilisation de méthodologies adaptées à l’analyse spatio-temporelle et de réseaux. Les résultats montrent des différences de PGVs dans les zones d’occupation du type Commerce/Industrie 25,74% et 30,77% et du type résidentiel 11,41% et 38,78% pour les régions Ouest/Mendanha et Trindade 2, respectivement pour les périodes (2011/2016) et (2009/2015). Cette dynamique d’occupation révèle une augmentation de +87% du total de voyages de flux des différents modes de transport et une croissance de +79% de l’indice de mobilité pour la période de 2013 à 2016, montrant la tendance de motorisation des régions et ses reflets sur la mobilité urbaine.
Mots clés: Occupation spatial. Système routier. Flux de véhicules. Transport. Mobilité.
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Lugiéry, Charles, Guillaume Lacquement, and Coline Perrin. "Des interstices agricoles investis par les Gitans et Voyageurs." Mélanges de l'École française de Rome. Italie et Méditerranée 135-2 (2023): 313–30. http://dx.doi.org/10.4000/11r7x.
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Cet article étudie la mobilisation des ressources agricoles par des groupes sociaux souvent identifiés comme Gitans ou Gens du voyage autour de Montpellier et de Perpignan. Il s’appuie sur une enquête par entretiens conduite auprès d’acteurs institutionnels et d’agriculteurs visant à comprendre le regard qu’ils portent sur les pratiques agricoles de ces groupes. La question de l’informalité est ici abordée en géographie par le prisme de l’interstice. De cette enquête se dégagent trois modalités d’investissement des interstices agricoles par les Gitans et Voyageurs : pour habiter, produire et valoriser économiquement les ressources agricoles des interstices. Cette lecture géographique des interstices montre l’ambivalence des expressions et des dynamiques socio-spatiales de l’informalité en agriculture dans les zones périurbaines quand sont concernés des groupes sociaux minoritaires.
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Larroque, Dominique, Michel Margairaz, and Pierre Zembri. "Nombre de voyageurs transportés dans Paris et sa region de 1871 à 1996." Flux 50, no. 4 (2002): 91. http://dx.doi.org/10.3917/flux.050.0091.
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Moroni, Thomas. "La régulation ordinaire des flux de voyageurs en gare : l’infrastructure à l’épreuve permanente." Flux N° 129-130, no. 3 (December 14, 2022): 29–43. http://dx.doi.org/10.3917/flux1.129.0029.
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Garedaghi, Yagoob, Patrice Bourée, and Francine Bisaro. "Cryptosporidiose au retour d’un voyage sous les tropiques, à propos de deux cas." Revue de biologie médicale N° 380, no. 5 (May 1, 2024): 51–56. http://dx.doi.org/10.3917/rbm.380.0051.
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Plus fréquente dans les zones tropicales défavorisées, la cryptosporidiose est une zoonose cosmopolite due à Cryptosporidium , un protozoaire responsable de diarrhées. Nous rapportons le cas de deux voyageurs, revenant d’une zone tropicale, confrontés à une diarrhée persistante causée par ce parasite et à la difficulté d’obtenir un traitement ad hoc par le nitazoxanide qui dispose d’une autorisation temporaire d’utilisation. La prévention de cette infection liée au péril fécal est difficile et il faut éviter d’absorber de l’eau de boisson non embouteillée et de consommer des crudités lors d’un séjour sous les tropiques.
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Ning, Jia. "Effects of Cropland Expansion on the Regional Land Surface Radiative Energy Balance and Heat Fluxes in Northern China." Applied Sciences 11, no. 4 (February 9, 2021): 1556. http://dx.doi.org/10.3390/app11041556.
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Land use change can impact the land surface radiation budget and energy balance by changing surface biophysical processes. Based on satellite remote sensing data and land use data from 2000 to 2015, we quantitatively estimated radiative forcing induced by cropland expansion during the early 21st century in northern China. The results showed that heat flux from the land surface to the atmosphere due to cropland expansion was quite variable in different climate zones. The heat flux increased in humid North China, whereas it decreased in arid Northwest China, semiarid Inner Mongolia, and humid Northeast China. Cropland expansion from woodland areas led to a general decline in the land surface heat flux to the atmosphere, which led to a cooling effect on the climate. The surface heat flux to the atmosphere due to cropland expansion in grassland areas displayed significant variations in different climate zones. The surface heat flux decreased only in humid Northeast China and arid Northwest China. The net surface radiation and latent heat flux both increased when grasslands were changed into cropland, but to different extents, which produced the differences in the surface heat flux to the atmosphere between different zones.
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Hatz, Christoph, Sarra Inoubli, Louis Loutan, Blaise Genton, Ron Behrens, and Markus Hufnagel. "[b]Encéphalite[/b] japonaise : risque pour les populations vivant en zones d’endémie et pour les voyageurs." Revue Médicale Suisse 6, no. 248 (2010): 956–59. http://dx.doi.org/10.53738/revmed.2010.6.248.0956.
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Cariou, Jean-Pierre, and Ludovic Thobois. "Détection et analyse automatique des aérosols atmosphériques par lidar infrarouge." Photoniques, no. 97 (July 2019): 30–35. http://dx.doi.org/10.1051/photon/20199730.
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Le changement climatique récent est attribué entre autres à l'impact des particules atmosphériques d’origine naturelle ou des activités humaines d’après le dernier rapport du GIEC [IPCC, Climate Change 2014: Synthesis Report]. Les aérosols affectent également les propriétés des nuages et influencent le cycle de l'eau, pouvant intensifier les moussons. En avril 2010, le volcan Eyjafjallajökull a créé un panache de plusieurs milliers de kilomètres sur l’Europe et causé la fermeture de plusieurs aéroports internationaux, clouant au sol des millions de voyageurs et causant une perte économique globale de 1,7 milliard de dollars. Tous les jours, les aérosols transfrontaliers (panaches de sable du Sahara, résidus de combustion des forêts canadiennes) affectent la santé des populations habitant notamment en zones urbaines ainsi que les activités économiques.
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O’Reilly, Carrie, Mauricio Silva, Samira Daneshgar Asl, William P. Meurer, and Ian R. MacDonald. "Distribution, Magnitude, and Variability of Natural Oil Seeps in the Gulf of Mexico." Remote Sensing 14, no. 13 (June 30, 2022): 3150. http://dx.doi.org/10.3390/rs14133150.
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The Gulf of Mexico is a hydrocarbon-rich region characterized by the presence of floating oil slicks from persistent natural hydrocarbon seeps, which are reliably captured by synthetic aperture radar (SAR) satellite imaging. Improving the state of knowledge of hydrocarbon seepage in the Gulf of Mexico improves the understanding and quantification of natural seepage rates in North America. We used data derived from SAR scenes collected over the Gulf of Mexico from 1978 to 2018 to locate oil slick origins (OSOs), cluster the OSOs into discrete seep zones, estimate the flux of individual seepage events, and calculate seep recurrence rates. In total, 1618 discrete seep zones were identified, primarily concentrated in the northern Gulf of Mexico within the Louann salt formation, with a secondary concentration in the Campeche region. The centerline method was used to estimate flux based on the drift length of the slick (centerline), the slick area, and average current and wind speeds. Flux estimates from the surface area of oil slicks varied geographically and temporally; on average, seep zones exhibited an 11% recurrence rate, suggesting possible intermittent discharge from natural seeps. The estimated average instantaneous flux for natural seeps is 9.8 mL s−1 (1.9 × 103 bbl yr−1), with an annual discharge of 1.73–6.69 × 105 bbl yr−1 (2.75–10.63 × 104 m3 yr−1) for the entire Gulf of Mexico. The temporal variability of average flux suggests a potential decrease following 1995; however, analysis of flux in four lease blocks indicates that flux has not changed substantially over time. It is unlikely that production activities in the Gulf of Mexico impact natural seepage on a human timescale. Of the 1618 identified seep zones, 1401 are located within U.S. waters, with 70 identified as having flux and recurrence rates significantly higher than the average. Seep zones exhibiting high recurrence rates are more likely to be associated with positive seismic anomalies. Many of the methods developed for this study can be applied to SAR-detected oil slicks in other marine settings to better assess the magnitude of global hydrocarbon seepage.
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Khamouli, Farida, Mosbah Zidani, Hichem Farh, Adel Saoudi, and L'hadi Atoui. "Effects of Cellulosic and Basic Flux on the Structure, Composition and Hardness of SMAW Welds on Steel X42." International Journal of Engineering Research in Africa 27 (December 2016): 11–19. http://dx.doi.org/10.4028/www.scientific.net/jera.27.11.
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This paper studied the effects of cellulosic and basic flux on the chemical composition, microstructure, formation of inclusions and micro hardness of X42 steel SMAW welds. The commercialized chemical compositions of flux used are: E6010, E8010-P1 and E8018-G, with electrodes of low carbon content. Welding conditions are not constant. The microstructure of the fusion zone for each flux consists mainly of acicular ferrite. It is found that manganese increases in the fusion zones (C, B and A) respectively .The change in mass concentration of manganese is homogeneous through the three points with all the used flux. Regardless of the flux used, the non-metallic inclusions observed are of two types: white and black. The micro-hardness decreasing values were obtained in the fusion zones (C, B and A).
Dissertations / Theses on the topic "Zones de flux de voyageurs"
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Vinson, Jean-Philippe. "Pôles générateurs de flux de déplacements non pendulaires dans une agglomération multipolarisée : contribution à une nouvelle approche des transports publics à travers le cas de la Métropole d’Aix-Marseille Provence." Electronic Thesis or Diss., Université Gustave Eiffel, 2025. https://these.univ-paris-est.fr/intranet/2025/UEFL-2025/TH2025UEFL2010.pdf.
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De nos jours, les déplacements dans une agglomération sont souvent abordés selon les phénomènes de pointe avec des heures éponymes calquées sur les déplacements pendulaires (MUNCH, 2017). Or, sur certains territoires, les « autres motifs » deviennent prépondérants. C’est le cas des Bouches-du-Rhône, dont la Métropole d'Aix-Marseille Provence s’y confond quasi-intégralement (EMD BDR 2009). Cette dernière intéresse de par sa taille (1,9 millions d’habitants), sa jeunesse institutionnelle (créée le 1er janvier 2016) et son caractère multipolaire unique englobant le grand périurbain. Le but de ce travail croisant aménagement, mobilité, ingénierie et sociologie a été d’évaluer puis optimiser la gestion des flux de déplacements non pendulaires (DNP) engendrés par les pôles générateurs métropolitains afférents, en vue de l'adaptation des réseaux de transport public soumis à des objectifs de report modal.Nous avons tâché d’y répondre en deux parties. Il y a d’abord une première partie de cadrage avec la définition des pôle générateurs de déplacements non-pendulaires (PG DNP) puis du contexte géographique et institutionnel de notre terrain d’études en montrant son caractère hétérogène et encore mouvant avant de s’intéresser aux enquêtes de déplacements et leur conception vis-à-vis des DNP, offrant une connaissance macroscopique des déplacements locaux. Puis, la deuxième partie voit la création d’un protocole d’étude des DNP à travers l’idée que les PG DNP exercent une pression résultante de la fréquentation d’usage ainsi que de son environnement dont une meilleure connaissance peut permettre une réduction de cette pression d’usage. Une approche catégorielle des DNP a ainsi été appliqué et a abouti à cinq types de PG DNP que nous avons tâché de caractériser plus finement à travers l’étude de nouvelles données (billettique, circulation et GPS), ce qui a eu pour résultat de révéler les différents rythmes de fonctionnement des catégories de PG DNP. Enfin le dernier chapitre traitant des flux de DNP à l’aune des visions opérationnelles et citoyennes a révélé les difficultés d’adaptation aux DNP d’un outil de simulation tel que Metropolis 13+ si ces flux ne sont pas pensés nativement, ainsi que la prise en compte des DNP de manière indifférenciée vis-à-vis des autres types de déplacement, dans un contexte d’offre locale de transports en commun encore considéré insuffisanteNowadays, commuting in an urban area is often addressed according to peak phenomena with eponymous hours modelled on commuting (MUNCH, 2017). In some jurisdictions, the “other grounds” become predominant. This is the case of the Bouches-du-Rhône, where the Aix-Marseille Provence Metropolis is almost entirely merged (EMD BDR 2009). The latter is interesting because of its size (1.9 million inhabitants), its institutional youth (created on January 1, 2016) and its unique multipolar character encompassing the large peri-urban. The aim of this work, which combines planning, mobility, engineering and sociology, was to evaluate and then optimize the management of non-commuting travel flows (NCT) generated by the related metropolitan generating poles, for the adaptation of public transport networks subject to modal shift objectives. We tried to answer it in two parts. There is first a first part of framing with the definition of non-commuting movement generating poles (NCT GP) the geographical and institutional context of our field of study by showing its heterogeneous character and still moving before being interested in travel surveys and their conception vis-à-vis the NCT, offering a macroscopic knowledge of local travel. The second part sees the creation of a protocol for studying NCT through the idea that GP NCT exert a pressure resulting from the use of frequentation and its environment, which a better knowledge can allow a reduction in this pressure. A categorical approach of the NCT was applied and resulted in five types of GP NCT that we tried to characterize more finely through the study of new data (ticketing, traffic and GPS), which resulted in revealing the different operating rhythms of GP NCT grades. Finally, the last chapter dealing with NCT flows in terms of operational and citizen visions revealed the difficulties of adapting to the NCT a simulation tool such as Metropolis 13+ if these flows are not thought natively, as well as the consideration of the NCT in an undifferentiated way vis-à-vis other types of travel, in a context of local public transport offer still considered insufficient
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Roos, Jérémy. "Prévision à court terme des flux de voyageurs : une approche par les réseaux bayésiens." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1170/document.
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Dans ces travaux de thèse, nous proposons un modèle de prévision à court terme des flux de voyageurs basé sur les réseaux bayésiens. Ce modèle est destiné à répondre à des besoins opérationnels divers liés à l'information voyageurs, la régulation des flux ou encore la planification de l'offre de transport. Conçu pour s'adapter à tout type de configuration spatiale, il permet de combiner des sources de données hétérogènes (validations des titres de transport, comptages à bord des trains et offre de transport) et fournit une représentation intuitive des relations de causalité spatio-temporelles entre les flux. Sa capacité à gérer les données manquantes lui permet de réaliser des prédictions en temps réel même en cas de défaillances techniques ou d'absences de systèmes de collecteIn this thesis, we propose a Bayesian network model for short-term passenger flow forecasting. This model is intended to cater for various operational needs related to passenger information, passenger flow regulation or operation planning. As well as adapting to any spatial configuration, it is designed to combine heterogeneous data sources (ticket validation, on-board counts and transport service) and provides an intuitive representation of the causal spatio-temporal relationships between flows. Its ability to deal with missing data allows to make real-time predictions even in case of technical failures or absences of collection systems
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Fure, Adrian D. "Relationships between mass and flux in dense nonaqueous phase liquid source zones." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011060.
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Marini, Jean-Christophe. "L'Hafnium dans les zones de subduction: Bilan isotopique des flux entrant et sortant." Phd thesis, Université Joseph Fourier (Grenoble), 2004. http://tel.archives-ouvertes.fr/tel-00006357.
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Dans les zones de subduction, le recyclage de sédiments vers le manteau et la remontée de magmas depuis le manteau jusqu'à la croûte des arcs insulaires représentent des échanges de matière entre la croûte continentale et le manteau terrestre. Nous avons examiné ces échanges de masse en utilisant les compositions isotopiques de l'Hafnium et du Néodyme. Dans la zone de subduction d'Izu-Mariannes, les sédiments subduits présentent des compositions isotopiques de l'Hf et du Nd équivalentes aux compositions de l'eau de mer du Pacifique. La croûte océanique altérée présente des compositions isotopiques identiques à une croûte océanique non-altérée. Dans les zones de subduction de Luzon et de Java, les laves d'arc présentent des compositions isotopiques de l'Hf très radiogéniques par rapport à leurs compositions isotopiques du Nd. Ces compositions des laves d'arc de Luzon et de Java semblent conditionnées par la contamination de leurs sources par des sédiments océaniques subduits.
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Gille, Julian. "Suivi et modélisation des flux dans un marais maritime : essais et tentative d'application sur la partie nord du marais breton." Nantes, 2013. http://www.theses.fr/2013NANT3025.
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Le Marais Breton est un marais littoral situé au sud de l'estuaire de la Loire. Son rôle bénéfique sur la qualité de l’eau est souvent mis en avant, mais jamais quantifié. Les habitats côtiers fournissent des services écosystémiques essentiels aux personnes et à l’environnement, notamment pour la qualité de l’eau. L’estimation du pouvoir épurateur de tels milieux est la plupart du temps basée sur un bilan des entrées et des sorties. La présente étude cherche à aller plus loin en tentant de tenir compte des processus de dégradation mis en jeu au cours du transit des masses d’eau dans le marais. La méthodologie proposée est basée sur la modélisation des flux d’eau et d’un pesticide (glyphosate) dans les principaux chenaux à l’aide d’un modèle hydraulique monodimentionnel (1D). Les simulations réalisées prouvent qu’il est possible de calculer des temps de concentration, de résidence et de transfert dans le marais, fonction des usages, des conditions hydro-météorologiques et des manœuvres d’ouverture / fermeture des ouvrages hydrauliques. Ces simulations révèlent également la possibilité de différencier les processus de dégradation et de dilution, et de les spatialiser. L’intégration de ce modèle dans une chaîne de modèles sur le continuum terre-mer s’avère possible et démontre l’intérêt de cet outil dans l’aide à la décision pour la gestion de ces milieux.
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Suchomel, Eric John. "Partial Mass Recovery from DNAPL Source Zones: Contaminant Mass Flux Reductions and Reductive Dechlorination of Residual DNAPL." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-08172006-160337/.
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Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2007.Koros, William, Committee Member ; Huang, Ching-Hua, Committee Member ; Hughes, Joseph, Committee Member ; Pennell, Kurt, Committee Chair ; Loeffler, Frank, Committee Member.
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Grasset, Charlotte. "Eutrophisation des zones humides : conséquences pour la qualité, la décomposition des plantes aquatiques et les flux de carbone." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10032.
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L'eutrophisation est une des principales menaces pesant sur les écosystèmes aquatiques. Cette thèse a pour objectifs de déterminer le rôle des paramètres abiotiques liés à l'eutrophisation, notamment la concentration en phosphore total, sur 1) la composition chimique des communautés végétales aquatiques, 2) leur décomposition et 3) les flux de C dans les zones humides. 1. Trois espèces aquatiques représentatives des trois stratégies adaptatives de Grime (i.e. compétitive, rudérale et stress tolérante) sont sélectionnées dans des zones humides distribuées le long d'un gradient de phosphore. Les espèces compétitives et rudérales ont une concentration en lignine significativement plus faible que l'espèce stress tolérante. Pour une même espèce, la teneur en eau augmente avec la concentration en phosphore de l'habitat et l'allocation en composés carbonés (amidon et/ou lignine) varie également significativement. 2. La composition des plantes aquatiques a un fort effet sur leur décomposition, les espèces rudérales et compétitives se décomposant plus vite, d'autant plus si elles se sont développées dans des sites riches en nutriments. 3. Dans les milieux eutrophes, les communautés végétales contribuent à l'augmentation des émissions de CH4 et diminuent les émissions de CO2 mesurées pendant la journée, probablement directement, au travers de leur qualité, de leur vitesse de décomposition, et des quantités de matières produites, et indirectement, au travers de leur position dans la lame d'eau. Le niveau d'eutrophisation des écosystèmes doit donc être pris plus explicitement en compte dans les modèles d'estimation des flux de carbone des milieux aquatiques d'eau douceEutrophication is a current threat for wetlands. This phD thesis aims at determining the role of the abiotic parameters of eutrophication, mainly the phosphorus content, 1) on aquatic plant quality, 2) on aquatic plant decomposition, and 3) on carbon fluxes. 1. Three aquatic plant species representative of the Grime strategies, i.e. competitive, ruderal and stress tolerant, were collected in wetlands dispatched along a phosphorus gradient. For the three species, water content of populations increased with the nutrient content of the habitat. Carbon allocation (starch and/or lignin) also varied according to habitat. 2. The three species were collected and decomposed in wetlands dispatched along a nutrient gradient. Aquatic plant quality significantly affected their decomposition, in particular the ruderal and competitive species were more rapidly decomposed when they grew in nutrient rich sites. 3. Daytime CO2 and CH4 fluxes were measured in 6 floristic zones. Daytime CO2 emissions were negatively correlated with net primary productivity and CH4 emissions were positively correlated. The abundance of floating vegetation also increased CH4 emissions probably because macroalgae and to a lower extent vascular plants with floating leaves favor anoxic conditions. Eutrophication may affect aquatic plant chemical composition and increase their decomposition rate. Moreover, in eutrophic wetlands, floating vegetation may affect carbon fluxes because of their quality, their decomposition rate and the quantities produced, and indirectly because of their location in water column. Therefore the eutrophication should be taken into account in the global C budgets of softwater ecosystems
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Labiadh, Mohamed Taieb. "Quantification de l'érosion éolienne sur des surfaces anthropisées : simulations des flux en masse à l'échelle des zones arides Tunisiennes." Paris 7, 2011. http://www.theses.fr/2011PA077072.
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The aim of this work is to present a methodology permitting to quantify wind erosion, in particular the fluxes in mass on the southern Tunisian arid regions, A particular attention has been carried to the description and the assessment of the modifications of land use {extension of culture, change of agricultural practices, etc. ). An approach combining simulations in laboratory, experiences on parcels and modelling is implemented. Otherwise, this last technique, modelling, is considered like one main tools of investigating permitting to give elements of answer to the final objectives of this work. Some specific parametrisations bas been developed on the laboratory permitting, consequequently to describe the erosion fluxes on agricultural surfaces (Kardous. 2005a, 2005b). These relations, allow to derive solely from the geometric features of the ridged surfaces (the height, RH, and the spacing, RS) the aerodynamic roughness height (-„), the erosion threshold friction velocity and the saltation fluxes. To validate these parametrisation in situ, we had conduct in southern Tunisian arid region three experiences (2003. 2008 and 2009} on parcels plowed by three different tools (the disc, the moulboard and the tiller). These experiences show, on one hand that the model developed on the laboratory' reproduces very well the experimental results and describes on a satisfying way the saltation fluxes on agricultural surfaces in Tunisian arid zones. On the other hand, theses results indicate also that erosion fluxes are smaller for the mouldboard, intermediate with the tiller and the higher for the disc. To simulate the emission of erosion fluxes the scale of arid and desert Tunisian zones, we used a meso-scale model, the regional Atmospheric Modeling System (RAMS) coupled on line with the Dust production model (DPM) developed by Marticorena and Bergametti (1995) and Laurent (2005). We had, first identified the most frequent and intense simulated zones sources of clust emission, We evaluated also the relative contribution of both natural surfaces and land agricultural uses to the fluxes in mass. The results suggest that the wind erosion stays predominant on the natural surfaces. Finally. A very marked seasonal cycle of the emissions is simulated with a maximum in the spring and in the beginning of the summer. This cycle is mainly due to the high wind speed generally observed on this period of year. Iron dust solubility in atmospheric waters is critical to estimate the effect of its deposition on primary production, especially on global carbon cycle. My PhD studies the effect of atmospheric organic complexation on iron dust dissolution. First of all, I studied the water soluble fraction of collected aerosols in the source region during strong biomass burning event, an important source of organic compounds. Second of all, I performed laboratory experiments with dust particles from different African sources and different organic compounds measured in the atmosphere. This work have highlight that the variability of iron dust solubility could be linked to the organic complexation. Oxalic acid is the most important iron ligand in the atmosphère and is the one with the most important effect on iron solubility, but others organic compounds such as malonic, tartane, glycolic acids or HULIS could enhanced the dissolution of iron. This dissolution, without light, is reductive and lead to the formation of Fe(II). I found a linear dissolution for dust iron in presence of increasing concentration of oxalate and HULIS, but for the other compounds the dissolution seems to be limited. I also found that the mineralogical composition of iron contained in dust is very important, and the dissolution is controlled by me presence of iron from clay minerals rather than iron from (hydr-)oxides.
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Wang, Runying. "Phytoépuration de boues biologiques provenant de l'industrie agroalimentaire : traitement par un système de marais artificiels à flux vertical en région méditerranéenne française." Aix-Marseille 1, 2009. http://www.theses.fr/2009AIX11028.
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Une expérimentation a été menée en mésocosmes pour simuler un marais artificiel à flux vertical pour traiter une boue biologique provenant d’une usine agroalimentaire. Un substrat organique (tourbe et écorces de pin) a été utilisé et trois espèces hélophytes (Phragmites australis Cav. , Typha latifolia L. Et Iris pseudacorus L. ) ont été testées. L’étude confirme la faisabilité de l’utilisation du substrat organique, sans colmatage à déplorer. Mais des matières organiques solubles sont libérées et présentent un risque d’enrichissement pour les eaux en sortie. Le système montrent des performances satisfaisantes : réduction hydrique entre 25% et 65%, élimination supérieure à 90% pour MES et DCO, et supérieure à 80% pour NTK. Phragmites est l’espèce la plus efficace en termes de traitement, suivie par Typha puis Iris, tous devant le système sol nu. Ceci met en avant le rôle positif du végétal et la variabilité entre les espèces. Le principal processus épuratoire est la filtration. Les plantes ont des effets positifs sur le traitement. De façon indirecte, le système racinaire intensifie la filtration et stimule les activités microbiennes ; les racines exsudent des substances organiques, telles que peroxydases, qui peuvent participer à la dégradation des contaminants. De façon directe, les plantes absorbent des éléments puis les stockent dans la biomasse; ce rôle direct des plantes est mineur mais non négligeable. Phragmites est l’espèce la plus efficace en raison de ses caractères les plus appropriés au traitement, comme par exemple une évapotranspiration forte, une forte capacité d’absorption, un système racinaire dense, extensif et profond et une forte activité enzymatiqueWe performed an experiment using a vertical-flow wetland system to treat a liquid sewage sludge from a food industry (producing soft drinks from fruit concentrates). An organic substrate (peat/crushed pine bark, 1/1) was used as growing medium and three helophyte species (Phragmites australis Cav. , Typha latifolia L. , and Iris pseudacorus L. ) were tested. Results confirmed that the organic substrate can be used in treatment system, without clogging observed. However, the substrate released soluble organic matter, which enriched outflow water. The treatment system showed high performance: water reduction varied from 25% to 65%; removal efficiency was more than 90% for MES and COD, and more than 80% for TKN. Overall, the system planted with Phragmites had the highest performance, followed by Typha and then by Iris, all beyond unplanted system. This highlights positive role of plants in the treatment and differences between species. The main purifying process was filtration of particles by substrate. Plants had positive impacts on treatment. Indirectly, plant root system strengthened filtration effect of substrate and enhanced microbial activity; roots released organic substances, such as peroxidises, which can participate in the degradation of organic contaminants. Directly, plants took up elements and stored them in their biomass; this direct role of plants was minor while not negligible. Phragmites was the species the most efficient because of its characteristics suitable for treatment, such as high evapotranspiration, high uptake capacity of nutrients, dense, extensive and deep root system and more active enzymes
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Raufaste, Nathalie. "Barrières au flux génique et sélection dans une zone hybride : étude théorique et expérimentale chez la souris domestique." Montpellier 2, 2001. http://www.theses.fr/2001MON20145.
Full textBooks on the topic "Zones de flux de voyageurs"
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Musielak, Z. E. Generation of flux tube waves in stellar convection zones. [Washington, DC: National Aeronautics and Space Administration, 1988.
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Jobs and Skills Programme for Africa. and World Employment Programme, eds. Les Flux migratoires et l'utilisation de la main-d'oeuvre dans les zones limitrophes de la CEPGL: Optique de l'application de la convention sur la libre circulation des personnes dans les états-membres de la CEPGL. Addis Ababa: Programme des emplois et des competences techniques pour l'Afrique, 1992.
Find full textBook chapters on the topic "Zones de flux de voyageurs"
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Meakin, Casey A., and W. David Arnett. "Some properties of the kinetic energy flux and dissipation in turbulent stellar convection zones." In Synergies between Solar and Stellar Modelling, 219–23. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9198-7_37.
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Singer, Bradley S., William P. Leeman, Matthew F. Thirlwall, and Nicholas W. Rogers. "Does Fracture Zone Subduction Increase Sediment Flux and Mantle Melting in Subduction Zones? Trace Element Evidence from Aleutian Arc Basalt." In Subduction Top to Bottom, 285–91. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm096p0285.
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SICARD, S., M. TANTI, C. FICKO, S. WATIER, R. MICHEL, and G. BÉDUBOURG. "Risques infectieux émergents ou ré-émergents pour les militaires en opération." In Médecine et Armées Vol. 46 No.1, 37–44. Editions des archives contemporaines, 2018. http://dx.doi.org/10.17184/eac.7367.
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Depuis le début des années 2000, les autorités sanitaires internationales ont observé une accélération de l’apparition ou la réapparition de maladies au fort potentiel épidémique. Ces émergences, ou réémergences, sont liées à plusieurs facteurs favorisants : le dérèglement climatique, la mondialisation de l’activité humaine et les importants flux de voyageurs ou de migrants. Les Forces armées françaises en opération sont exposées au risque de ces maladies émergentes. La compréhension de ces phénomènes est essentielle pour orienter la mise en place de mesures de prévention, ou de contre-mesures efficaces en cas d’épidémie au sein des forces. Dans cet article, après avoir expliqué les facteurs favorisants l’apparition des maladies émergentes et leur propagation, nous revenons sur plusieurs exemples récents d’émergence ou de réémergence virale et sur le risque encouru par les militaires français. Puis nous exposons quelques exemples d’outils pour la détection précoce de ces maladies.
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GAUTIER, Emmanuèle. "Les impacts du changement climatique sur les dynamiques hydrologiques des milieux périglaciaires de hautes latitudes." In Les impacts spatiaux du changement climatique, 145–68. ISTE Group, 2021. http://dx.doi.org/10.51926/iste.9009.ch7.
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La réponse des milieux périglaciaires de haute latitude au changement climatique est très marquée. La forte élévation des températures et la présence d’un pergélisol entraînent un bouleversement du fonctionnement hydrologique. L’accélération de la fonte du pergélisol augmente les flux d’eau des versants aux lits fluviaux. Ainsi la surface des lacs, des zones humides s’accroît et le débit des fleuves augmente.
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BEAUSSAC, M., V. POMMIER DE SANTI, H. SAVINI, F. SIMON, and R. MICHEL. "La bilharziose, problème de santé publique sous-évalué chez les militaires français ?" In Médecine et Armées Vol. 46 No.1, 45–52. Editions des archives contemporaines, 2018. http://dx.doi.org/10.17184/eac.7368.
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La bilharziose est une affection parasitaire due à un plathelminthe du genre Schistosoma. On estime que plus de 260 millions de personnes dans le monde sont infectées par ce parasite. De nombreux voyageurs (migrants, touristes ou militaires) se contaminent en zones d’endémie par contact avec de l’eau douce. La bilharziose est une pathologie de diagnostic difficile du fait d’une latence et d’une faible spécificité clinique, ainsi que d’une relative performance des examens biologiques. Elle est donc sous-estimée, y compris dans les armées. Malgré cela, plusieurs épidémies ont été rapportées dans les armées françaises depuis 2012. Il nous apparaît donc indispensable de mettre en place un dépistage de la bilharziose dans les armées françaises, visant entre autres à éviter les complications liées à cette affection par une prise en charge précoce des militaires infectés. Un projet d’étude clinique ayant pour objectif d’estimer la prévalence de l’exposition à la bilharziose et de mesurer la proportion d’infections bilharziennes parmi les militaires au retour de zone d’endémie a donc été élaboré. Après quelques rappels sur la bilharziose, les auteurs présentent ici les dernières investigations menées autour de cas de bilharziose ainsi que le projet d’étude clinique.
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Lodge, Sara. "Fantastic Books and Where to Find Them." In Libraries in Literature, 233–44. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192855732.003.0016.
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Abstract In Fantasy, libraries are often labyrinthine, like the brain itself; they are attractive repositories of magical power and secrets, but also dangerous zones where characters can become trapped. Books are frequently imaged as living forms that may fly, bite, or shriek. Authors of Fantasy sometimes stage conflict in the library between a conception of texts as static, orderly, authoritative repositories of predominantly male knowledge and a more fluid conception of texts as organic, generative bundles of cells whose implicitly female corpus revels in perpetual flux and multivalent modes of knowing. These authors stage metatextual debate between the genres of History and Fantasy in the library that asserts the power of Fantasy and its status within the Academy. In this genre, the book one finds in the library typically relates to one’s inner life: a text that can transform the dead language of knowledge into the living dialogue of action.
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Muniraj, Navya, Weixuan Gong, Muthu Kumaran Selvaraj, and Albert Simeoni. "A study of fire and plume dynamics for static pool fires and their interaction with vegetation." In Advances in Forest Fire Research 2022, 1566–71. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_238.
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Prescribed burns are an essential tool of fire management to reduce the impact and occurrence of wildfires. While managing prescribed burns, the smoke trajectory and downwind exposure to smoke are intimately coupled with the smoke production dynamics and the development of the fire plume in the vicinity of the fire front. In turn, the fire plume development is strongly coupled to fire behavior and the flow environment near the fire. This work aims at understanding fire behavior and plume development while interacting with vegetation at the large laboratory scale through experiments and modeling. In order to investigate these coupled processes, initially, flame and plume behavior from a static fire source will be characterized. A rectangular pool fire fueled by diesel is used and point measurements of flow, temperature and heat flux will be conducted. The burning rate will be measured using a load cell. K-type thermocouples and bi-directional pressure probes will be used for measuring the temperature and velocity, respectively in the flame and plume zones. These data will be used for validating a numerical model for simulating pool fires and the model will be subsequently used for predicting the plume interaction with vegetation. A Douglas fir tree, whose properties are well defined in the literature, will be used as vegetation. The Lagrangian particle model available in the Fire Dynamics Simulator (FDS) will be used to model the tree. The tree will be of regular shape and size with foliage and different classes of wood segregated based on typical size (diameter) range. The bulk density of the tree will be varied to replicate the systematic and controlled variation of the flow obstruction encountered by the plume and gives a realistic prediction of velocity, temperature, and heat flux within the vegetation. In the future, experiments with vegetation located in the plume region will be conducted to validate the numerical predictions.
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Lundstrom, C. C., X. Lin, K. Brueckel, C. Campe, X. Nan, K. Ortega, P. Akrie, M. Yu, and S. Marshak. "New mechanism for forming thick granitic continental crust at Phanerozoic convergent margins." In In the Footsteps of Warren B. Hamilton: New Ideas in Earth Science. Geological Society of America, 2022. http://dx.doi.org/10.1130/2021.2553(20).
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ABSTRACT Phanerozoic continental subduction zones have produced thick continental crust composed almost entirely of granitoid plutons. While ideas about how plutons form have evolved from models that envisioned large, highly molten magma bodies, the exact processes involved remain debated. Geochronology and seismology have led to the view that plutons form by incremental emplacement; stacked sills represent one type of incremental model whereby granitoids grow top-down by sills underplating their predecessor. Still, many questions remain unanswered, including why sill-like contacts are not often seen in more mature plutons, why the mafic residuum is not observed with many granitoid plutons, why some plutons are compositionally zoned (and others are not), and why geochemical characteristics of intrusions systematically change during magmatic cycles. Here, we propose a hypothesis for the construction of batholiths by amalgamation of plutons formed in a two-stage process. During stage 1, intermediate-composition sills underplate previous sills, forming a moving reaction zone mafic complex that produces a thickening granitoid as the process moves downward. The top of this mafic complex also releases a water-rich, low-temperature silicate liquid (LTSL), which begins ascent by reactive porous flow. During stage 2, the upward flux of LTSL further differentiates the overlying granitoids, increasing silica by 5%–10% and resulting in linear “mixing-like” behavior on Harker diagrams. Multiple plutons building downward in a magmatic cycle thicken the crust, leading to garnet gabbro mafic complexes forming at ~20 km depth. Their high density leads to delamination and net silicification of continental crust. The continuous flux of LTSL up through the arc crust can explain many geochemical spatial-temporal trends found in magmatic cycles, including Pb isotope evolution and increasing Fe3+, and provides a mechanism for addition of water to the upper crust, leading to sustained volcanism through time.
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Hamill, Chad S. "The Earth Is (Still) Our Mother." In Transforming Ethnomusicology Volume II, 115–25. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197517550.003.0007.
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As many large-scale protests by Indigenous people have articulated, lands inhabited by Indigenous communities (such as desert margins, small islands, lakes and rivers, high-altitude zones, and the circumpolar Arctic) are particularly vulnerable to the dramatic shifts in climate currently underway. The delicate ecosystems upon which Indigenous communities rely are in flux, and the accelerating rate of climate change—outpacing the direst scientific projections—amounts to a crisis that is every bit as threatening as the legacy of European colonialism. Fortunately, for millennia Indigenous communities have cultivated an intimate awareness of their ecology and have remained, throughout the era of world-wide industrial devastation, adept at adapting to environmental change. This awareness and adaptive power has been discussed within the framework of Traditional Ecological Knowledge (TEK). Using traditional stories and songs in Indigenous communities as a touchstone, this chapter will explore three interrelated aspects of TEK: (1) its role in assisting Indigenous communities in adapting to the effects of climate change; (2) its potential to inform and influence Western-generated climate science; and (3) its promise as a unifying thread tying Indigenous communities together, strengthening global self-determination.
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Tian, Wenjing, Herman Peiffer, Benny Malengier, Gang Liu, and Qingchao Cheng. "Numerical Investigation of Rainfall Infiltration-Induced Slope Stability Considering Water-Air Two-Phase Flow." In Current Perspectives on Applied Geomorphology [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.113723.
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For insights into rainfall infiltration on soil slopes and coupled transmission mechanisms, two-phase flow and finite element analysis were employed to examine water and air movement during the Shuping landslide. The results indicated a division of the landslide surface into two zones: an upper inflow area and a lower overflow area, driven by contrasting inflow and outflow directions. The total water and air flux remained stable, minimally affected by external factors such as rainfall attributes, surface runoff, and air temperature variations. In the inflow area of the slope surface, when rainfall intensity was greater than the total rate of the infiltration of water and air, the magnitude of infiltration equalled to the total rate infiltration of water and air, and runoff generation occurred in this area. Conversely, when infiltration matched rainfall intensity, runoff was absent in this area. In addition, water pressure in the saturated area of the slope surface can be transferred to the groundwater of the slope by pore air pressure, which could also increase the pressure head of the groundwater, and this was also detrimental to slope stability. Regarding uniform rainfall, it significantly reduces the safety factor, potentially making it the most hazardous pattern for slope failure.
Conference papers on the topic "Zones de flux de voyageurs"
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Simek, James C. "The Effects of Angular Displacement on Magnetic Flux Leakage Metal Loss Signals." In CORROSION 2009, 1–10. NACE International, 2009. https://doi.org/10.5006/c2009-09122.
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Abstract Magnetic flux leakage is one of the most common and robust methods of ILI (In Line Inspection) used by pipeline operators worldwide to detect and characterize a broad range of pipeline features and anomalies. Magnetic flux leakage data signals are influenced by the shape and configuration of metal loss zones; with the feature shapes used as a basis for algorithm development and interpretation techniques developed to provide estimates of metal loss lengths, widths and depths. For pipelines, primary lengths and widths of features may be oriented in any random direction with respect to the pipeline axis and applied magnetic fields. In addition to field levels, material properties, velocity effects, length, width, and depth, feature orientation will also influence the magnetic field data acquired for typical pipeline metal loss anomalies. Difficulties encountered in characterizing specific classes of metal loss features have led to the development, implementation, and use of tools employing multiple axis sensors in an effort to improve performance for these categories of metal loss features. To demonstrate the effects of feature orientation, examples will be presented with the results providing insights into the signal response for metal loss zones as the angular orientation of the features are varied within the applied magnetic field.
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O’Kane, J. M., T. F. Rudd, D. Cooke, F. W. H. Dean, and S. W. Powell. "Detection and Monitoring of Naphthenic Acid Corrosion in a Visbreaker Unit Using Hydrogen Flux Measurements." In CORROSION 2010, 1–15. NACE International, 2010. https://doi.org/10.5006/c2010-10351.
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Abstract Corrosion rates of up to 0.8 mm/per month were detected on a Visbreaker fractionation column. Internal examination of the column showed that the shell corrosion was confined to the vicinity of four trays situated approximately two thirds of the way up the column, with the highest rates being seen within the downcomers. Examination of the corroded areas within the downcomers indicated the presence of smooth, uniform zones of metal loss characteristic of organic acid corrosion. Further analyses of both the internal deposits and sections of shell plate taken from the areas of high corrosion indicated that organic acids were present. While the column was on-line, hydrogen flux measurements were recorded in the areas of active corrosion in order to provide an estimate of the corrosion rate in real time, to monitor the extent of active corrosion, to determine the probable cause of corrosion and to assess the effectiveness of a newly-initiated corrosion inhibitor program. The corrosion rate estimations were found to correlate well with ultrasonic thickness measurements. Hydrogen flux measurements also confirmed that the injection of a filming amine inhibitor was effective in reducing the corrosion rate of the affected area by 10-fold, despite the high temperature of up to 220°C
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Chung, H. M., J. h. Park, W. E. Ruther, J. E. Sanecki, R. V. Strain, and N. J. Zaluzec. "Stress Corrosion Cracking of Austenitic Stainless Steel Core Internal Weld." In CORROSION 1999, 1–23. NACE International, 1999. https://doi.org/10.5006/c1999-99443.
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Abstract Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L as well as 304 SS core shroud welds and mockup shielded-metal-arc welds were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on grain boundaries. However, as a result of exposure to weld fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests indicate also that fluorine exacerbate the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds.
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Hargrave, Robert, and Norris Johnston. "A Deposit-Related Problem in the Lower Wall of a Kraft Recovery Boiler." In CORROSION 2006, 1–19. NACE International, 2006. https://doi.org/10.5006/c2006-06464.
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Abstract Following a deposit-related overheating failure of a smelt spout opening tube in a single-drum Kraft recovery boiler, an investigation was initiated to focus on deposit mechanisms in the waterwall tubing. During the next scheduled outage, a similar spout opening was removed for destructive testing. Highly localized zones of thick deposit were documented inside the composite tube opening, while immediately adjacent areas inside the tubing were clean. The deposit morphology suggests steam pockets formed inside the spout opening tubes because of departure from nucleate boiling (DNB), which is a function of heat flux and circulation. Additional damaged composite tubes from this unit were evaluated over an eight-year period. Nearly all of the problem tubes contained excessive levels of waterside deposits, which led to corrosion thinning of the stainless steel cladding, overheating, and thermal fatigue cracking. Video probe inspections and deposit-weight density (DWD) tests revealed the vast majority of the boiler was clean. There was no evidence that the recurring tube problems were caused by water quality or water treatment issues. A Pitot tube study confirmed poor circulation in a composite spout opening tube during a period of upset operations, which suggests inadequate circulation was the probable root cause for the deposition and tube damage in the lower wall of this unit. Modification of the boiler design did not remedy the problem.
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Johnson, Kristian C., Daniel T. MacLauchlan, H. Josiah Phan, B. Blake Wiggins, Cody D. Williams, and Jonathan Tatman. "Evaluation of Highly Irradiated Stainless Steel and Nickel-based Materials using Phased Array Ultrasonic Inspections." In AM-EPRI 2024, 397–408. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.am-epri-2024p0397.
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Abstract Nuclear reactor inspections occasionally identify degraded materials in irradiated reactor components. Although mechanical repair options are possible, these repair solutions may be cost prohibitive or impractical to implement due to access restraints and/or the severity of the degradation. Welding repair of reactor components may input excessive heat into these irradiated materials resulting in diffusion of trace amounts of helium within the grain boundaries of the weld heat-affected zone (HAZ). Intergranular HAZ cracking can then result from the combination of this helium diffusion and high localized tensile stresses generated during weld cooling. It is therefore critical to characterize these zones and understand limitations for welding highly irradiated components to prevent helium-induced cracking. To accomplish this, typical reactor structural materials including Types 304L and 316L stainless steels and nickel-based Alloy 600/182 materials irradiated within the High Flux Isotope Reactor facility at Oak Ridge National Laboratory were used in this study for welding and evaluation. A phased array ultrasonic inspection system has been developed to characterize cracking in the weld samples. It provides remote controlled scanning and minimizes handling the samples, minimizing operator dose. The samples are inspected from the side opposite of the welds. The material and weld grain noise were evaluated at 10 MHz and found to be conducive to detecting cracking in the material and welds. Inspection of the samples comprises a 10 MHz phased array probe sweeping a focused longitudinal wave from -60° to 60° while the probe is raster scanned over the sample in small increments. The collected data is analyzed using UltraVision 3. Several of the irradiated samples were inspected prior to welding. Some of the samples had what appear to be small lamination defects in them. One irradiated welded sample has been tested to date with no cracking detected, which has been confirmed by destructive examination.
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Peng, Li, Zhao Qi-Jun, and Zhu Qiu-xian. "CFD Calculations on the Unsteady Aerodynamic Force of Tilt-rotor in Conversion Mode." In Vertical Flight Society 70th Annual Forum & Technology Display, 1–12. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9422.
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In order to calculate the unsteady aerodynamic force of tilt-rotor in conversion mode, VBM (Virtual Blade Model), RBM (Real Blade Model) and HBM (Hybrid Blade Model) are established respectively. A new multi-layer moving-embedded grid technique is presented to reduce the numerical dissipation of the tilt-rotor wake. In this method, grid generated abound the rotor accounts for rigid blade motions and a new searching scheme is implemented to search suitable donor elements in moving-embedded grids to translate information between the viscous flow and inviscid flow zones. In these CFD methods, a dual-time method is employed to fulfil the calculation of unsteady flowfield of tilt-rotor, and a second-order centred difference scheme by introducing artificial viscosity is used to calculate the flux. In order to improve the computing efficiency, the SMPD model parallel acceleration technology adopted, according to the characteristics of the current grid system. The lift and drag distributions of NACA0012 airfoil, the dynamic pressure distributions on a typical rotor and the sectional pressure distributions on XV-15 tilt-rotor in hovering flight are calculated respectively, and the developed VBM and RBM model are validated by comparing the calculated results with available experimental data. Then, unsteady aerodynamic force and flowfield of XV-15 tilt-rotor in different modes, such as fixed conversion mode at different tilt angles (15-deg, 30-deg, 60-deg), and full conversion cases from 0-deg to 90-deg, are numerically simulated by the VBM/RBM/HBM respectively. By analyses and comparisons on the simulated results about unsteady aerodynamic forces of tilt-rotor in different modes, some meaningful conclusions about distorted blade-tip vortex distribution and unsteady aerodynamic force variation in conversion mode are obtained, and these investigated results could provide a good foundation for tilt-rotor aircraft design in the future.
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Pierrel, F., and M. Newborough. "Heat Flux Maps for Ovens: Concept of Baking Comfort Zones." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41891.
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Achieving rapid baking in industrial tunnel ovens, while maintaining adequate product quality is a significant challenge. The application of excessive heat fluxes to a low-diffusivity heterogeneous food product can easily yield a product of poor quality (color, texture, flavour). It is desirable to optimize the application of heat on a transient basis during the baking process in order to minimize bake times and achieve an acceptable set of product responses (e.g. color, height, crust hardness, crumb moisture, weight loss). The magnitudes of the convective, radiative, condensing/evaporating and conductive heat fluxes dictate the quality of the baked product and the process efficiency. By mapping the applied fluxes with time a “baking comfort zone” can be established. The map can be developed to indicate minima and maxima flux values and/or to identify an optimal heating profile. The baking comfort zone for a given product provides a useful visual indicator, which can be related to a similar indicator of product responses to improve understanding of the baking process. Furthermore, provided adequate instrumentation is available, the baking comfort zone can be utilized (i) by the operator of an oven at the process control interface to ensure that an appropriate heating profile is being achieved in practice; and (ii) to replicate products in different ovens. This concept is based upon baking tests conducted on a high performance research oven manufactured by APV Baker (UK) and installed in their research centre in Peterborough England.
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Gollahalll, S. R., and B. Nanjundappa. "Turbulent Gas Jet Flames in Cross-Flow at Low Momentum Flux Ratios." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-442.
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An experimental study of the stability and structure of a propane gas jet flame in cross-flow at a low jet to cross-flow momentum flux ratio (0.024) is presented. The flame structure is characterized by two distinct zones. A two-dimensional flow recirculation zone attached to the burner tube in its wake forms the first zone. An axisymmetric flow follows the first zone downstream. The junction of the two zones is characterized by an intense mixing of jet and cross-flow streams. This paper deals with the structure of the first zone. The temperature and concentration profiles show that the physico-chemical processes and combustion in that zone are diffusion controlled.
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Tian, Weixue, and Wilson K. S. Chiu. "Calculation of Direct Exchange Areas for Non-Uniform Zones." In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47479.
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This paper presents a special transformation of variables to reduce a double integral into three single integrals and its use for calculating Direct Exchange Areas (DEA) in Zonal method. This technique was originally presented for calculation of DEA using a uniform zone system in a cylindrical enclosure. However, non-uniform zones are needed for applications with large thermal gradients. Thus we extended this technique to calculate the DEA for non-uniform zones in an axisymmetrical cylinder system. At least six times of saving in computational time was observed in calculating DEA compared with cases without transforming of variables. It is shown that accuracy and efficiency of estimation of radiation heat flux is improved when using a non-uniform zone system. Reasonable accuracy of all DEA are calculated without resorting to the conservative equations. Results compared well with analytical solutions and numerical results of previous researchers. A brief discussion of its application in calculating DEA in a 3-D rectangular enclosure is also provided.
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Sahai, Vivek, and Salvador M. Aceves. "Analysis of Heat Transfer During Quenching of a Gear Blank." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-1073.
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Abstract This paper presents experimental and numerical results for the quench of a gear blank in agitated and stagnant oil. Temperatures within the gear blank are determined with a whole domain-optimizer technique inverse solution method, to calculate the time history at every point in the gear blank. The development of this procedure represents the first stage in an overall analysis of the quench process that will later include material phase transformations and deformation. The paper presents ten variations in setting up the inverse problem, to analyze which combination of independent variables and decision variables results in the best match between experimental and numerical results. The results indicate that dividing the boundary of the gear blank into four zones and assigning a fixed heat transfer coefficient or heat flux to each zone yields an average RMS error (average difference between experimental and numerical results) of the order of 40 K. This error can be reduced by either increasing the number of zones, by reducing the number of thermocouples being matched, or by allowing the heat transfer or heat flux to vary within the zones. Of these possibilities, variation of heat transfer within the zones gives the best improvement in the quality of the match for the amount of extra computational effort required to run the problem.
Reports on the topic "Zones de flux de voyageurs"
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Chen, Z., S. E. Grasby, W. Yuan, M. Colpron, and X. Liu. Methodology study of geothermal resource evaluation using remote-sensing and ground-surface temperature data, Burwash Landing, Yukon – status and preliminary results. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/p15d0hqc2g.
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Trouver des ressources énergétiques renouvelables pour atteindre les objectifs du gouvernement visant à atteindre zéro émission nette d’ici 2050 est l’un des plus grands défis auxquels nous sommes confrontés, en particulier dans le Nord. Les communautés du Nord sont en grande partie déconnectées du réseau énergétique nord-américain et dépendent plutôt des hydrocarbures importés pour leur chauffage et leur électricité. Une étude antérieure (par exemple Grasby et al., 2011) suggérait que le Yukon et le nord-est de la Colombie-Britannique constituaient des régions à fort potentiel pour les ressources géothermiques. Des travaux supplémentaires montrent le potentiel de l'énergie géothermique pour soutenir les communautés du Nord (Grasby et al., 2012). De nouvelles techniques de géophysique, de télédétection et de surveillance de la température de surface du sol (GST) pour l'évaluation géothermique ont été développées dans le cadre du projet géothermique Garibaldi (Grasby et al., 2021 ; Chen et al. 2023). Cette étude explore la faisabilité de l'utilisation d'images multispectrales de télédétection de Landsat 8 et des séries chronologiques GST du réseau de surveillance GST pour révéler la relation entre le système de failles profondes et le flux de chaleur souterrain en tant qu'outil d'évaluation des ressources géothermiques pour le nord du Canada. GSC et YSG ont déployé un réseau de surveillance de la température à la surface du sol au cours de l'été 2022, et les données de 65 stations ont été récupérées au cours de la saison de terrain 2023. Un traitement préliminaire a été effectué pour détecter les zones de flux de chaleur élevé. Deux ensembles d'images multispectrales Landsat-8 dans la zone de Burwash Landing de différentes saisons ont été collectées et traitées pour l'extraction de caractéristiques à l'aide d'algorithmes ML. Les données GST et les caractéristiques extraites des images Landsat ont été analysées pour déterminer si les anomalies géothermiques sont liées à des caractéristiques géologiques spécifiques, telles que des systèmes de failles profondes. Nous rapportons ici les résultats préliminaires en mettant l'accent sur l'analyse des données sur la TPS.
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Chen, Z., S. E. Grasby, C. Deblonde, and X. Liu. AI-enabled remote sensing data interpretation for geothermal resource evaluation as applied to the Mount Meager geothermal prospective area. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330008.
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The objective of this study is to search for features and indicators from the identified geothermal resource sweet spot in the south Mount Meager area that are applicable to other volcanic complexes in the Garibaldi Volcanic Belt. A Landsat 8 multi-spectral band dataset, for a total of 57 images ranging from visible through infrared to thermal infrared frequency channels and covering different years and seasons, were selected. Specific features that are indicative of high geothermal heat flux, fractured permeable zones, and groundwater circulation, the three key elements in exploring for geothermal resource, were extracted. The thermal infrared images from different seasons show occurrence of high temperature anomalies and their association with volcanic and intrusive bodies, and reveal the variation in location and intensity of the anomalies with time over four seasons, allowing inference of specific heat transform mechanisms. Automatically extracted linear features using AI/ML algorithms developed for computer vision from various frequency bands show various linear segment groups that are likely surface expression associated with local volcanic activities, regional deformation and slope failure. In conjunction with regional structural models and field observations, the anomalies and features from remotely sensed images were interpreted to provide new insights for improving our understanding of the Mount Meager geothermal system and its characteristics. After validation, the methods developed and indicators identified in this study can be applied to other volcanic complexes in the Garibaldi, or other volcanic belts for geothermal resource reconnaissance.
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Swanson and Kilman. L51506 Development of Improved Methods for Inspecting Gas Storage Well Downhole Casing. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 1986. http://dx.doi.org/10.55274/r0010199.
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Casing corrosion in storage wells is a matter of considerable concern to the gas storage industry. Such wells are typically flowed through the casing rather than through production tubing, to facilitate high flow capacities. When failures occur, gas leakage to surrounding formations, freshwater zones and to the surface can pose a sizable economic loss as well as a serious safety hazard. For these reasons, monitoring corrosion in down-hole casing in gas storage fields has become a major concern of many storage field operators, and the in situ detection and assessment of corrosion damage by means of logging instruments is a significant part of this effort. The study reported in this document has sought to investigate in detail the objectives, methods and results of currently available commercial logging devices as a first step in determining whether down-hole corrosion damage can be more accurately characterized by improved logging methods. Of the several methods potentially capable of meeting the through-wall measurement requirement, only two form the basis for current commercial corrosion logs: the flux leakage, or magnetic perturbation technique, and the remote field eddy current approach. In seeking to provide reasonably short term performance improvements to the industry, it was decided in this project to pursue refinements of magnetic perturbation logs for two reasons: first, the shortcomings evidenced by present logs of this type appear to be amenable to relatively simple improvement, and second, the remote field eddy current approach, while useful as an adjunct to damage assessment, offers little promise of sizing individual corrosion flaws.
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Goerzen, C., H. Kao, R. Visser, R. M. H. Dokht, and S. Venables. A comprehensive earthquake catalogue for northeastern British Columbia, 2021 and 2022. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/332532.
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Ce rapport de fichier ouvert présente les résultats de la surveillance sismique globale menée dans le nord-est de la Colombie-Britannique (NE BC) en 2021 et 2022. L'effort de surveillance englobe deux zones primaires d'observation sismique : la zone de surveillance etd'atténuation sismique de Kiskatinaw (KSMMA) et la zone de condition de permis de surveillance du mouvement du sol (GMMPCA), chacune étant caractérisée par des opérations pétrolières et gazières différentes, ainsi que par des densités de population. Un flux de travail de pointe basé surl'apprentissage automatique a été utilisé pour la détection des tremblements de terre et la détermination des phases. Une étape de révision manuelle a été incluse pour garantir la qualité de toutes les détections et localisations de tremblements de terre. Du 1er janvier 2021 au 31 décembre 2022, untotal de 9655 événements sismiques ont été détectés, avec un taux mensuel moyen de 420 événements. Le KSMMA a enregistré 8468 événements au cours de cette période, caractérisés par un regroupement serré, tandis que le GMMPCA a enregistré 899 événements. Des variations dans les taux de sismicité ontété observées par rapport aux rapports précédents, potentiellement influencées par des changements dans les activités industrielles et les capacités de surveillance sismique. L'ampleur de l'exhaustivité pour le KSMMA est passée à 1,01, reflétant les changements dans le réseau de surveillancesismique, tandis que le GMMPCA a affiché une ampleur de l'exhaustivité de 1,45, légèrement supérieure à celle de la période de rapport précédente. Ce rapport souligne la nature dynamique de la sismicité induite dans le nord-est de la Colombie-Britannique, en insistant sur la nécessité d'unesurveillance continue, de mesures d'atténuation adaptatives et d'une collecte robuste de données sismiques pour éclairer la prise de décision et améliorer la préparation aux tremblements de terre.
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Sakulneya, Apidej, and Jeffery Roesler. Smart Construction Work-Zone Safety with V2I Passive Material Sensing. Illinois Center for Transportation, December 2024. https://doi.org/10.36501/0197-9191/24-027.
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This study explored new vehicle to infrastructure (V2I) technology in construction work zones (CWZ), where speeding, unsafe driving behaviors, and drivers' failure to obey traffic signs contribute significantly to elevated accident rates and fatalities. The objective of this research to advance CWZ safety by evaluating the potential of 3-axis magnetometers attached to a moving cart and traversing over a pavement-assisted passive sensing system can improve vehicle lateral positioning and warning in CWZ. Secondly, to develop a process to implement a programmable ferromagnetic oxide material for roadway coatings to interface with vehicles containing magnetometers on a field site. The research testing used a custom-built cart equipped with multiple 3-axis magnetometer to detect EM signals from invisible markings composed of 10% and 20% CrO₂, that were created to alert for speed, lane merges, and lane-keeping. The invisible marking strips were oriented and positioned in various ways to test the repeatability and ability to reliable detect a signal and signature that could be interpreted with automated algorithm. The experimental test results were acquired in a parking and signal-processing technique was established that normalized the raw signals, removed background EM signals not related to the created EM signatures, filtered high- and low-frequency noise, and took the derivative of the EM flux density with respect to the number of points. The V2I signals in the Y and Z-axes occasionally failed to exceed the minimum threshold set for the experiments, but the X-axis signals consistently exceeded the minimum value of ±200nT throughout the testing. The minimum threshold signals were used to calculate the speed of the cart, indicate a lane merge, and determine the lateral lane position of the cart. The detected speed signals closely correlated with the GPS speed measurements on the cart as well as provided accurate cart positioning and maneuvering actions. This pilot study demonstrated the potential of V2I communication specifically EM pavement signatures to enhance CWZ safety and provide detectable and actionable feedback to the vehicle.