1,720,966 research outputs found
Étude multidisciplinaire pour la caractérisation du fonctionnement hydrogéologique d’aquifères volcaniques : cas du volcan Bromo-Tengger, Java Est, Indonésie
No full textAbstractVolcanoes are environments combining hazards and natural resources, the latter justifying the high population density living on many active volcanoes in tropical contexts. More than a source of construction materials, some volcanoes are considered as "water castles", providing important possibilities for drinking groundwater supply through complex and sometimes artesian aquifer systems. The Bromo-Tengger volcano aquifer system in East Java, Indonesia, is a strategic resource with its main artesian spring Umbulan, which partly supplies the second biggest city of Indonesia (Surabaya). For more than a decade, this resource has been under increasing pressure with an increase of water abstraction for agricultural practices, industrial development, population growth and is amplified by increasingly accessible drilling techniques. Known as one of the most visited stratovolcanoes in worldwide, the aquifer potential of the Bromo-Tengger was barely studied until now.As part of this thesis, a multidisciplinary approach was used to characterize the hydrogeology of the northern flank of the volcano and its downstream artesian plain. Geological and geophysical results have highlighted the lithology and the geometry of the volcano's aquifer formations. The outflow context of natural major artesian springs of volcanic piedmonts area such as Umbulan has been identified.The climatic conditions were characterized with the installation of new meteorological stations along the northern flank and completed by the monitoring of a representative watershed. Compared with hydrochemical and isotopic data, they allowed a quantitative analysis of the distribution of the recharge and the elaboration of a first hydrogeological conceptual model. The recharge covers the whole northern flank of the volcano (≈66% of the rain) with a preferential recharge zone identified at about 1000 m elevation mainly due to orographic effects. Conceptually, infiltrated waters supply a binary system composed of: a network of high elevation perched aquifers feeding all or part of a low-lying basal aquifer. This latter becomes confined towards the plain through a multi-layer artesian aquifer, explaining the high aquifer productivity of the area.A new measurement device at free-flowing artesian well has been developed, combining hydraulic tests and piezometric measurement. Their interpretation allows both estimating the hydrodynamic parameters and drawing a piezometric map of the artesian aquifer of Pasuruan. These last results, made it possible to define the main flow directions and systems as well as an estimate of groundwater transit time.A first steady-state numerical flow model shows good consistency with the conceptual model previously developed. It allows a better understanding of the hydrogeological functioning in the present and pre-exploitation conditions. Compared with the water age dating analyses, it allows to discuss the most realistic flow model to consider at the scale of the volcano.This research provides new insights in the understanding of hydrogeology of andesitic stratovolcanoes in volcanic arc position under tropical climate including a caldera, high-elevation perched aquifers with a multi-layered and artesian volcano-sedimentary plain.Keywords: Hydrogeology, Bromo-Tengger volcano, conceptual hydrogeolgoical model of volcanic aquifer, volcano-sedimentary plain, artesianism, recharge, multidisciplinaryLes volcans sont des espaces qui combinent aléas et ressources naturelles, cette dernière justifiant la forte densité de population vivant sur de nombreux volcans actifs en milieu tropical. Au-delà d’une source de matériaux de construction, certains volcans sont considérés comme de véritables châteaux d’eau, offrant d’importantes possibilités d’adduction d’eau potable au travers de systèmes aquifères complexes et parfois artésiens. Le système aquifère du volcan Bromo-Tengger à l’Est de l’Ile de Java en Indonésie représente une ressource stratégique grâce à sa principale source artésienne Umbulan qui alimente en partie la deuxième plus grande ville d’Indonésie (Surabaya). Depuis plus d’une décennie, cette ressource subit une pression croissante avec une augmentation des besoins en eau pour les pratiques agricoles, le développement industriel, l’augmentation de la population et est accentuée par des techniques de forage de plus en plus accessibles. Connu comme l’un des stratovolcans les plus visités au monde, le potentiel aquifère du Bromo-Tengger n’était jusqu’ici que très peu étudié.Dans le cadre de ce travail, une approche multidisciplinaire a été utilisée pour caractériser l’hydrogéologie du flanc Nord du Bromo-Tengger et sa plaine artésienne.Les résultats géologiques et géophysiques ont permis de préciser la lithologie et la géométrie des formations aquifères du volcan mais également d’identifier le contexte d’émergence des exutoires naturels telles que les grandes sources artésiennes de piedmonts volcaniques.Les conditions climatiques ont été caractérisées avec la mise en place de stations météorologiques le long du flanc Nord du volcan et complétées par l’instrumentation d’un bassin versant représentatif. Confrontées aux données hydrochimiques et isotopiques, elles ont permis une analyse quantitative de la distribution de la recharge et l’élaboration d’un premier modèle conceptuel hydrogéologique. La recharge s’effectue sur tout le flanc du volcan (≈66% de la pluie) avec une zone préférentielle de recharge identifiée vers 1000 m d’altitude due principalement aux effets orographiques. Conceptuellement, les eaux infiltrées alimentent un système binaire composé d’un réseau d’aquifères perchés alimentant tout ou partie un aquifère libre de base dont la partie terminale devient captive vers la plaine au travers d’un aquifère artésien multicouche, expliquant les fortes productivités aquifères de la zone.Un nouveau dispositif de mesure sur forages artésiens a été développé, combinant essai par pompage et mesure du charge hydraulique. Leur interprétation permet d’estimer les paramètres hydrodynamiques ainsi que la réalisation une carte piézométrique de l’aquifère artésien de Pasuruan. Ces derniers résultats, ont permis de définir les principales directions et systèmes d’écoulement ainsi que les temps de transit.Un premier modèle numérique d’écoulement en régime permanent montre une bonne cohérence avec le modèle conceptuel précédemment développé. Il permet une meilleure compréhension du fonctionnement hydrogéologique dans la situation présente et celle de pré-exploitation. Confronté aux données d’analyse d’âge de l’eau souterraine dans la plaine, il permet de discuter du modèle d’écoulement le plus réaliste à considérer à l’échelle du volcan.Ces travaux de recherche contribuent à améliorer la connaissance hydrogéologique des stratovolcans andésitiques en position d’arc volcanique sous climat tropical, incluant une caldera, des aquifères perchés de haute altitude ainsi qu’une plaine volcano-sédimentaire multicouche et artésienne
Étude multidisciplinaire pour la caractérisation du fonctionnement hydrogéologique d’aquifères volcaniques : cas du volcan Bromo-Tengger, Java Est, Indonésie
No full textAbstractVolcanoes are environments combining hazards and natural resources, the latter justifying the high population density living on many active volcanoes in tropical contexts. More than a source of construction materials, some volcanoes are considered as "water castles", providing important possibilities for drinking groundwater supply through complex and sometimes artesian aquifer systems. The Bromo-Tengger volcano aquifer system in East Java, Indonesia, is a strategic resource with its main artesian spring Umbulan, which partly supplies the second biggest city of Indonesia (Surabaya). For more than a decade, this resource has been under increasing pressure with an increase of water abstraction for agricultural practices, industrial development, population growth and is amplified by increasingly accessible drilling techniques. Known as one of the most visited stratovolcanoes in worldwide, the aquifer potential of the Bromo-Tengger was barely studied until now.As part of this thesis, a multidisciplinary approach was used to characterize the hydrogeology of the northern flank of the volcano and its downstream artesian plain. Geological and geophysical results have highlighted the lithology and the geometry of the volcano's aquifer formations. The outflow context of natural major artesian springs of volcanic piedmonts area such as Umbulan has been identified.The climatic conditions were characterized with the installation of new meteorological stations along the northern flank and completed by the monitoring of a representative watershed. Compared with hydrochemical and isotopic data, they allowed a quantitative analysis of the distribution of the recharge and the elaboration of a first hydrogeological conceptual model. The recharge covers the whole northern flank of the volcano (≈66% of the rain) with a preferential recharge zone identified at about 1000 m elevation mainly due to orographic effects. Conceptually, infiltrated waters supply a binary system composed of: a network of high elevation perched aquifers feeding all or part of a low-lying basal aquifer. This latter becomes confined towards the plain through a multi-layer artesian aquifer, explaining the high aquifer productivity of the area.A new measurement device at free-flowing artesian well has been developed, combining hydraulic tests and piezometric measurement. Their interpretation allows both estimating the hydrodynamic parameters and drawing a piezometric map of the artesian aquifer of Pasuruan. These last results, made it possible to define the main flow directions and systems as well as an estimate of groundwater transit time.A first steady-state numerical flow model shows good consistency with the conceptual model previously developed. It allows a better understanding of the hydrogeological functioning in the present and pre-exploitation conditions. Compared with the water age dating analyses, it allows to discuss the most realistic flow model to consider at the scale of the volcano.This research provides new insights in the understanding of hydrogeology of andesitic stratovolcanoes in volcanic arc position under tropical climate including a caldera, high-elevation perched aquifers with a multi-layered and artesian volcano-sedimentary plain.Keywords: Hydrogeology, Bromo-Tengger volcano, conceptual hydrogeolgoical model of volcanic aquifer, volcano-sedimentary plain, artesianism, recharge, multidisciplinaryLes volcans sont des espaces qui combinent aléas et ressources naturelles, cette dernière justifiant la forte densité de population vivant sur de nombreux volcans actifs en milieu tropical. Au-delà d’une source de matériaux de construction, certains volcans sont considérés comme de véritables châteaux d’eau, offrant d’importantes possibilités d’adduction d’eau potable au travers de systèmes aquifères complexes et parfois artésiens. Le système aquifère du volcan Bromo-Tengger à l’Est de l’Ile de Java en Indonésie représente une ressource stratégique grâce à sa principale source artésienne Umbulan qui alimente en partie la deuxième plus grande ville d’Indonésie (Surabaya). Depuis plus d’une décennie, cette ressource subit une pression croissante avec une augmentation des besoins en eau pour les pratiques agricoles, le développement industriel, l’augmentation de la population et est accentuée par des techniques de forage de plus en plus accessibles. Connu comme l’un des stratovolcans les plus visités au monde, le potentiel aquifère du Bromo-Tengger n’était jusqu’ici que très peu étudié.Dans le cadre de ce travail, une approche multidisciplinaire a été utilisée pour caractériser l’hydrogéologie du flanc Nord du Bromo-Tengger et sa plaine artésienne.Les résultats géologiques et géophysiques ont permis de préciser la lithologie et la géométrie des formations aquifères du volcan mais également d’identifier le contexte d’émergence des exutoires naturels telles que les grandes sources artésiennes de piedmonts volcaniques.Les conditions climatiques ont été caractérisées avec la mise en place de stations météorologiques le long du flanc Nord du volcan et complétées par l’instrumentation d’un bassin versant représentatif. Confrontées aux données hydrochimiques et isotopiques, elles ont permis une analyse quantitative de la distribution de la recharge et l’élaboration d’un premier modèle conceptuel hydrogéologique. La recharge s’effectue sur tout le flanc du volcan (≈66% de la pluie) avec une zone préférentielle de recharge identifiée vers 1000 m d’altitude due principalement aux effets orographiques. Conceptuellement, les eaux infiltrées alimentent un système binaire composé d’un réseau d’aquifères perchés alimentant tout ou partie un aquifère libre de base dont la partie terminale devient captive vers la plaine au travers d’un aquifère artésien multicouche, expliquant les fortes productivités aquifères de la zone.Un nouveau dispositif de mesure sur forages artésiens a été développé, combinant essai par pompage et mesure du charge hydraulique. Leur interprétation permet d’estimer les paramètres hydrodynamiques ainsi que la réalisation une carte piézométrique de l’aquifère artésien de Pasuruan. Ces derniers résultats, ont permis de définir les principales directions et systèmes d’écoulement ainsi que les temps de transit.Un premier modèle numérique d’écoulement en régime permanent montre une bonne cohérence avec le modèle conceptuel précédemment développé. Il permet une meilleure compréhension du fonctionnement hydrogéologique dans la situation présente et celle de pré-exploitation. Confronté aux données d’analyse d’âge de l’eau souterraine dans la plaine, il permet de discuter du modèle d’écoulement le plus réaliste à considérer à l’échelle du volcan.Ces travaux de recherche contribuent à améliorer la connaissance hydrogéologique des stratovolcans andésitiques en position d’arc volcanique sous climat tropical, incluant une caldera, des aquifères perchés de haute altitude ainsi qu’une plaine volcano-sédimentaire multicouche et artésienne
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
