31 research outputs found

    Применение нейросетевых технологий для измерений параметров вибрации объектов с неплоской поверхностью

    Get PDF
    Было проведено компьютерное моделирование электродинамической системы интерференционного измерителя параметров вибраций объектов с неплоской поверхностью. Показано, что применение нейросетевых технологий позволяет использовать интерференционный метод для измерения параметров перемещений объектов с неплоской поверхностью. Полученные результаты обработки данных компьютерного моделирования свидетельствуют об эффективности практического применения нейронных сетей для обработки сигналов трёхзондового интерференционного сверхвысокочастотного измерителя.Було проведено комп'ютерне моделювання електродинамічної системи інтерференційного вимірювача параметрів вібрацій об'єктів з неплоскою поверхнею. Показано, що застосування нейромережевих технологій дозволяє використовувати інтерференційний метод для вимірювання параметрів переміщень об'єктів з неплоскою поверхнею. Отримані результати обробки даних комп'ютерного моделювання свідчать про ефективність практичного застосування нейронних мереж для обробки сигналів тризондового інтерференційного надвисокочастотного вимірювача.An electrodynamical system of an interference vibration meter for objects with a non-planar surface is simulated using a computer. It is shown that neural technologies allow to use an interference method for measuring parameters of the moving objects with a non-planar surface. The results obtained of processing data of a computer simulation show the effectiveness of the practical application of neural networks for processing signals of the trisounder interference microwave meter

    A New Pterosaur (Pterodactyloidea: Azhdarchidae) from the Upper Cretaceous of Morocco

    Get PDF
    The Kem Kem beds in South Eastern Morocco contain a rich early Upper (or possibly late Lower) Cretaceous vertebrate assemblage. Fragmentary remains, predominantly teeth and jaw tips, represent several kinds of pterosaur although only one species, the ornithocheirid Coloborhynchus moroccensis, has been named. Here, we describe a new azhdarchid pterosaur, Alanqa saharica nov. gen. nov. sp., based on an almost complete well preserved mandibular symphysis from Aferdou N'Chaft. We assign additional fragmentary jaw remains, some of which have been tentatively identified as azhdarchid and pteranodontid, to this new taxon which is distinguished from other azhdarchids by a remarkably straight, elongate, lance-shaped mandibular symphysis that bears a pronounced dorsal eminence near the posterior end of its dorsal (occlusal) surface. Most remains, including the holotype, represent individuals of approximately three to four meters in wingspan, but a fragment of a large cervical vertebra, that probably also belongs to A. saharica, suggests that wingspans of six meters were achieved in this species. The Kem Kem beds have yielded the most diverse pterosaur assemblage yet reported from Africa and provide the first clear evidence for the presence of azhdarchids in Gondwana at the start of the Late Cretaceous. This, the relatively large size achieved by Alanqa, and the additional evidence of variable jaw morphology in azhdarchids provided by this taxon, indicates a longer and more complex history for this clade than previously suspected

    Variations in the global water budget

    No full text

    Complex coacervates formed across liquid interfaces : A self-consistent field analysis

    No full text
    The Scheutjens-Fleer self-consistent field (SF-SCF) theory is used to study complexation between two oppositely charged polyelectrolytes across an interface formed by two solvents, here called oil and water. The focus is on the composition and the lateral stability of such interfacial coacervate. One polyelectrolyte is chosen to be oil soluble and the other one prefers water, whereas the counter and salt ions are taken to distribute ideally over all phases. There exists an electrostatic associative driving force for the formation of the coacervate phase which increases with decreasing ionic strength and may be assisted by some specific affinity between the associating units and an effective poor solvency for the coacervate. As with respect to the lateral stability an unusual wetting scenario, called pseudo-partial wetting, presents itself, which results from interactions on two different length scales. On the segmental length the screening of oil-water contacts promotes the wetting by the coacervate: a pre-wetting jump-like transition takes place off-coexistence from a microscopically thin to a mesoscopically thin film. Usually this implies complete wetting. However, the mesoscopically thin film is exposed to long-ranged attractive electrostatic interactions and therefore cannot grow to macroscopic dimensions upon approach towards coexistence. Hence the system remains partial wet. The bulk correlation length controls the thickness of the mesoscopically thin film and as a result the wetting transition occurs extremely close to the bulk critical point. We therefore expect that a thick coacervate film typically is laterally inhomogeneous: there are drops on top of a mesoscopically thin coacervate film. This conclusion qualitatively explains the experimental observation that such a coacervate film scatters visible light

    Marqueurs biogéochimiques d'aridité dans l'estuaire du Sénégal et le Manga nigérien(Biogeochemical process of aridity in the Senegal estuary and the nigerian Manga plain)

    No full text
    In the Manga, of Niger (North-West of Lake Chad), the depressions between dunes have kept the mark of water table fluctuation related to climate. The succession of events is : sedimentation of diatomite, nodulation of concretions of sodium silicates, leaching of sodium from silicates. - In the Senegal valley, brackish water mollusc extention are related to marine water invasion. They indicate repeated arid years as shown by hydrologic and climatic survey of the last 80 years.Dans le Manga nigérien (Nord-Ouest du lac Tchad) les dépressions interdunaires gardent la trace de variations sensibles de la nappe phréatique liées au climat avec la succession des événements suivants : mise en place des diatomites, concrétionnement silicaté sodique, évacuation du sodium des silicates. - Dans la vallée du fleuve Sénégal, les faunes saumâtres de Mollusques sont à rapporter à des périodes suffisamment arides pour que la remontée saline annuelle ait atteint une ampleur, une durée dans l'année et une répétition d'une année à l'autre suffisantes, ainsi que le montre l'analyse hydrologique et climatique des 80 dernières années.Icole Michel, Gac J.-Y., Monteillet J., Faure Hugues. Marqueurs biogéochimiques d'aridité dans l'estuaire du Sénégal et le Manga nigérien(Biogeochemical process of aridity in the Senegal estuary and the nigerian Manga plain). In: Bulletin de l'Association de géographes français, N°483-484, 59e année, Janvier-février 1982. pp. 61-64
    corecore