Texte remanié de: Dissertation--Fachbereich Literaturwissenschaft--Universität Konstanz, 2002. / Bibliogr. p. 193-204.

Texte remanié de: Diss.--University of Helsinki, 1995. / Bibliogr. p. 139-160. Index.

Diss.--Fachbereich Neuere Fremdsprachen und Literaturen--Marburg an der Lahn--Philipps-Universität, 1988.

The thesis examines the presence of Demeter in Hellenistic poetry, while it also considers the way contemporary Demeter cult informs the poetic image of the goddess. My research focuses on certain poems in which Demeter is in the foreground, that is, Philitas’ Demeter, Callimachus’ Hymn to Demeter, Theocritus’ Idyll 7, and Philicus’ Hymn to Demeter, supplemented by the epilogue of Callimachus’ Hymn to Apollo and Philicus’ Hymn to Demeter. The first part of my study is dedicated to the presentation of the evidence for Demeter’s role in the religious life of places that are directly or indirectly associated with the poems I discuss, that is, Egypt, Cyrene, Cos and Cnidus, in order to establish the cultic and historical framework within which Demeter’s literary figure appears. In the second part I closely examine the poems that feature Demeter and conclude that the goddess and motifs closely linked with her have poetological significance, which supports the view that Demeter functions as a symbol of poetics. Furthermore, I examine the social elements in the narrative of the most extant Hellenistic poem on Demeter, i.e. Callimachus’ Hymn to Demeter, and propose that these reflect Demeter’s role as a ‘social’ goddess.

Th.--University of Pennsylvania, 1976. / Bibliogr. à la fin de chaque chap. et p. 243-249. Index.

Texte abrégé de: Diss.--Philosophische Fakultät--Universität zu Köln, 1995. / Résumé en italien. Bibliogr. p. 10-16. Index.

Researchers at the NASA Langley Research Center (LaRC) are developing a next-generation instrument for monitoring the Earth radiation budget (ERB) from low Earth orbit. This instrument is called the DEMonstrating the Emerging Technology for measuring the Earth's Radiation (DEMETER) instrument. DEMETER is a candidate to replace the Clouds and Earth's Radiant Energy System (CERES) instruments which currently monitor the ERB. LaRC has partnered with the Thermal Radiation Group at Virginia Tech to model and evaluate the thermal and optical design of the DEMETER instrument. The effort reported here deals with the numerical modeling of the optical and thermal radiative performance the DEMETER instrument. The numerical model is based on the Monte Carlo Ray-Trace (MCRT) method. The major optical components of the instrument are incorporated into the ray-trace model using 3-D surface equations. A CAD model of the instrument baffle is imported directly into the ray-trace environment using an STL triangular mesh. The instrument uses a single freeform mirror to focus radiation on the detector. A method for incorporating freeform surfaces into a ray-trace model is described. The development and capabilities of the model are reported. The model is used to run several ray-traces to compare two different quasi-black surface coatings for the DEMETER telescope baffle. Included is a list of future tests the Thermal Radiation Group will use the model to accomplish. / Master of Science / For decades NASA has used satellite-mounted scientific instruments to monitor the Earth radiation budget (ERB). The ERB is the energy balance of the planet Earth with its surroundings. Radiation from the sun is absorbed and reflected by the Earth. The Earth also emits radiation. The balance between these heat transfer components drives the planetary climate. Researchers at the NASA Langley Research Center (LaRC) are developing a new instrument for monitoring the ERB from low Earth orbit. This Earth observing instrument is called the DEMonstrating the Emerging Technology for measuring the Earth's Radiation (DEMETER) instrument. NASA has partnered with the Thermal Radiation Group at Virginia Tech to model and evaluate the thermal and optical design of the DEMETER instrument. The effort reported here deals with the numerical modeling of radiation heat transfer in the DEMETER instrument. The numerical model uses the Monte Carlo Ray-Trace (MCRT) method to evaluate the thermal and optical behavior of the DEMETER instrument. The development and capabilities of the model are reported. The model is used to run a series of simulations to compare the performance of two different quasi-black surface coatings for the DEMETER telescope baffle. Included is a list of future tasks the Thermal Radiation Group will accomplish using the model.

Although lightning-generated whistlers have been studied for nearly a century, there are still questions to be answered. It is clear that, at least in a certain frequency range, these waves significantly contribute to the overall wave intensity in the inner magnetosphere. They also influence distribution functions of energetic particles in the Van Allen radiation belts. Thanks to the on-board implemented neural network for automated whistler detection, we can relate electromagnetic wave and energetic particle flux measurements performed by the low-altitude DEMETER spacecraft with the number and dispersion of whistlers detected during a certain time interval. We distinguish the cases with high and low whistler occurrence and we use this information to determine the overall effect of lightning-generated whistlers. Powered by TCPDF (www.tcpdf.org)

David PÍŠA Study of electromagnetic emissions recorded by the DEMETER satellite Abstract : This thesis presents results based on wave measurements performed by the DEMETER space- craft. This French spacecraft was operating between 2004 and 2010 at the altitude of ∼660 km. We focus on measurements of the electromagnetic waves and plasma density in the vicinity of imminent earthquakes. In the first part, we present a study of plasma density variations in the vicinity of a very powerful earthquake in Chile (Mw 8.8) which occurred on February 27, 2010. Data recorded before the main shock along orbits close to the future epicenter showed increasing plasma den- sities. A statistical analysis using 4 years of data to monitor density variations under similar conditions has been performed. This study shows that a large increase of the plasma density is very uncommon at this location. In the second part, a statistical study (∼6.5 years) of variations of VLF wave intensity is shown. We have analyzed all available data measured close (in time and space) to large earth- quakes (M≥5). Data related to more than 12000 earthquakes have been compared with an unperturbed background distribution. We confirm the previously reported results of a statis- tically significant decrease of the wave intensity at frequencies of about...

Cette thèse présente des résultats basés sur les mesures d'ondes réalisées par le satellite DEMETER. Ce satellite français a été exploité entre les années 2004 et 2010 à l'altitude de ~660 km. Nous nous sommes concentrés sur les mesures des ondes électromagnétiques et de la densité du plasma au voisinage des tremblements de terre imminents .Dans la première partie, nous présentons une étude des variations de la densité du plasma dans le voisinage d'un tremblement de terre très puissant au Chili ( Mω 8.8) qui a eu lieu le 27 Février 2010. Les données enregistrées avant le choc principal le long des orbites proches de l'épicentre ont montré des augmentations de densité du plasma. Dans une deuxième étape, une analyse statistique a été effectuée en utilisant 4 ans de données pour suivre les variations saisonnières de densité. Cette étude montre qu'une augmentation forte de la densité du plasma est très rare dans cette région à l'époque du séisme. Dans la deuxième partie, une étude statistique (~6,5 ans) des variations de l'intensité des ondes TBF est montrée. Nous avons analysé toutes les données mesurées disponibles à proximité (en temps et en distance) de grands séismes (M> ou = 5). Les données relatives à plus de 12000 tremblements de terre ont été comparées avec une distribution de référence non perturbée. Nous confirmons les résultats déjà rapportés de la diminution statistiquement significative de l'intensité des ondes à des fréquences de l'ordre de ~1,7 kHz. Cet effet semble être lié à une diminution de la limite inférieure de l'ionosphére qui affecte les ondes TBF qui se propagent dans le guide Terre-ionosphère. / This thesis presents results based on wave measurements performed by the DEMETER spacecraft. This French spacecraft was operating between 2004 and 2010 at the altitude of ~660 km. We focus on measurements of the electromagnetic waves and plasma density in the vicinity of imminent earthquakes. In a first part, we present a study of plasma density variations in the vicinity of a very powerful earthquake in Chile ( Mω 8.8) which occurred on February 27, 2010. Data recorded before the main shock along orbits close to the future epicenter showed increasing plasma densities. In a second step, a statistical analysis using 4 years of data to monitor density variations under similar conditions has been performed. This study shows that a large increase of the plasma density is very uncommon at this location and at this time. In a second part, a statistical study (~6.5 years) of variations of VLF wave intensity is shown. We have analyzed all available data measured close (in time and in distance) to large earthquakes (M> ou = 5). Data related to more than 12000 earthquakes have been compared with an unperturbed background distribution. We confirm the previously reported results of a statistically significant decrease of the wave intensity at frequencies of about ~1.7kHz. This effect seems to be related to a decrease of the lower ionospheric boundary which affects the VLF waves propagating in the Earth-ionosphere waveguide.