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Sample records for dem gebiete der

  1. Neue Erkenntnisse auf dem Gebiete der Parasitologie und der parasitären Erkrankungen des Menschen

    NASA Astrophysics Data System (ADS)

    Piekarski, G.

    1980-01-01

    The increasing interest in the parasites of man in the Federal Republic of Germany is connected with the unbounded keenness of German people to travel. They favor southern regions with warm climates which are usually infested with parasites. Thus the general practitioner is nowadays confronted in his daily routine with “imported” pathogenic organisms and diseases as yet unknown to him or with which he need not have reckoned in the past. Furthermore, new information now exists on the development of well-known parasites of our regions, which can be pathogenic to man. Fortunately, new reliable drugs have come on the market, rendering some parasitic diseases harmless.

  2. Sterblichkeit: der paradoxe Kunstgriff des Lebens - Eine Betrachtung vor dem Hintergrund der modernen Biologie

    NASA Astrophysics Data System (ADS)

    Verbeek, Bernhard

    Leben gibt es auf der Erde seit fast 4 Mio. Jahren, trotz allen Katastrophen. Die Idee des Lebens scheint unsterblich. Der Tod aber offenbar auch. Jedes Lebewesen ist davon bedroht, ja für Menschen und andere "höhere“ Lebewesen ist er im Lebensprogramm eingebaut - todsicher. Diese Tatsache ist alles andere als selbstverständlich. Ist sie überhaupt kompatibel mit dem Prinzip der Evolution, nach dem der am besten Angepasste überlebt?

  3. Der Kalte Krieg in der Peripherie Griechische Physiker und Atomenergie nach dem Zweiten Weltkrieg

    NASA Astrophysics Data System (ADS)

    Vlahakis, George N.

    Die vorliegende Arbeit analysiert Ansichten griechischer Physiker zur Atomenergie und deren mögliche Anwendung nach dem Zweiten Weltkrieg, insbesondere während des Kalten Kriegs. Einerseits werden Ansichten von Physik- Professoren griechischer Universitäten präsentiert - beispielsweise von Dimitrios Hondros, der Student von Arnold Sommerfeld und Mitarbeiter von Peter Debye in München war, und andererseits wird die Politik der griechischen Regierung für die Etablierung eines Forschungsinstitutes diskutiert, das der Entwicklung der Atomenergie dienen sollte; ebenfalls wird eine öffentliche Meinungsumfrage zu diesen Thema, die in den Tageszeitungen der damaligen Zeit präsentiert wurde, diskutiert.

  4. Elektronenröhrenforschung nach 1945 Telefunkenforscher in Ost und West und das Scheitern des Konzepts der „Gnom-Röhren“ in Erfurt

    NASA Astrophysics Data System (ADS)

    Dörfel, Günter; Tobies, Renate

    Elektronenröhren standen wegen ihrer Rüstungsrelevanz nach Kriegsende unter dem Vorbehalt der Besatzungsmächte. Unter dem Druck eigener materieller Defizite erlaubte und initiierte die sowjetische Besatzungsmacht Entwicklungen dazu eher als die westlichen Alliierten. Daraus resultierten bemerkenswerte Innovationen und Vorsprünge im Gebiet von Miniaturröhren.

  5. Melker Meilensteine auf dem Weg in ein naturwissenschaftliches Zeitalter - Glanzlichter der Ausstellung zum Internationalen Astronomiejahr 2009 in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.; Zotti, Georg

    2009-06-01

    Das Mittelalter wird weithin als die dunkle Epoche in der Geschichte der Europäischen Wissenschaften betrachtet, und insbesondere das Leben in den Klöstern galt lange Zeit als frei von jeglichem Interesse für Naturwissenschaften abseits der Medizin. Im Mittelalter galt die Astronomie bloß als Mittel zum Zweck, um religiöse und zivile Kalender erstellen zu können. Durch den Bestand der Handschriftenkammer der Melker Stiftsbibliothek eröffnet sich uns eine neue Sichtweise auf das gegen Ende des Mittelalters wachsende Interesse an den Naturwissenschaften. Dies wurde durch die starke Aufwertung der Klosterbibliothek im Rahmen der 'Melker Reform' im 15. Jahrhundert noch weiter verstärkt. Diese Epoche fällt mit der Frühphase der Universität Wien und der 'ersten Wiener Schule der Astronomie' zusammen. Dieser Artikel beleuchtet ausgewählte astronomischen Werke in der Melker Stiftsbibliothek zwischen dem frühen 9 und dem 18. Jahrhundert. Einen Schwerpunkt stellt das Wirken der Wiener Schule der Astronomie dar, wobei wir u.a. die Melker Abschrift von Peuerbachs Gutachten über den Kometen von 1456 sowie die im Stift Melk durchgeführte Beobachtung der Mondfinsternis von 1457 durch Regiomontanus und Peuerbach beleuchten. Dieser Beitrag ist der einführende Übersichtsartikel zum Ausstellungsprojekt in der Melker Stiftsbibliothek im Rahmen des Internationalen Jahres der Astronomie 2009. The medieval period is commonly seen as a dark epoch for science in Europe. Especially monasteries were seen as institutions without interest in natural sciences except for medicine. Astronomy was allegedly only a tool to construct religious and civil calendars. The inventory of the medieval manuscript collection of the library of the Abbey of Melk allows a new view on the growing interest in the exact sciences towards the end of the medieval ages. This interest was intensified through the increased importance of the monastery library due to the monastery reform

  6. Ökophysik: Plaudereien über das Leben auf dem Land, im Wasser und in der Luft

    NASA Astrophysics Data System (ADS)

    Nachtigall, W.

    Prof. em. Dr. rer. nat. Werner Nachtigall, geb. 1934, war als Zoophysiologe und Biophysiker Leiter des Zoologischen Instituts der Universität des Saarlandes in Saarbrücken. In Forschung und Ausbildung hat er sich insbesondere mit Aspekten der Technischen Biologie und Bionik befasst und mit seinen Forschergruppen viele Basisdaten insbesondere zur Ökologie, Physiologie und Physik des Fliegens und Schwimmens aber auch zur Stabilität beispielsweise der Gräser erarbeitet. Lebewesen überraschen immer wieder durch ihre "Biodiversität", ihre hochspezifischen Ausgestaltungen und Anpassungen.

  7. Elektromagnetische Strahlung. Informationen aus dem Weltall.

    NASA Astrophysics Data System (ADS)

    Schäfer, H.

    Contents: Informationen aus dem Weltall. Neue und zukünftige Geräte. Wichtiges und Interessantes aus der Positionsastronomie. Die Helligkeit der Sterne und anderer astronomischer Objekte. Spektroskopie und Spektralanalyse. Beobachtungen außerhalb des optischen Bereiches.

  8. Wiederbeginn nach dem Zweiten Weltkrieg

    NASA Astrophysics Data System (ADS)

    Strecker, Heinrich; Bassenge-Strecker, Rosemarie

    Dieses Kapitel schildert zunächst die Ausgangslage für die Statistik in Deutschland nach dem Zweiten Weltkrieg: Der statistische Dienst in den Besatzungszonen musste teilweise erst aufgebaut und der statistische Unterricht an den Hochschulen wieder in Gang gebracht werden. In dieser Lage ergriff der Präsident des Bayerischen Statistischen Landesamtes, Karl Wagner, tatkräftig unterstützt von Gerhard Fürst, dem späteren Präsidenten des Statistischen Bundesamtes, die Initiative zur Neugründung der Deutschen Statistischen Gesellschaft (DStatG). Die Gründungsversammlung 1948 im München wurde zu einem Meilenstein in der Geschichte der DStatG. Ziel war es, alle Statistiker zur Zusammenarbeit anzuregen, ihre Qualifikation an das internationale Niveau heranzuführen und die Anwendung neuerer statistischer Methoden in der Praxis zu fördern. Es folgten 24 Jahre fruchtbarer Arbeit unter Karl Wagner (1948-1960) und Gerhard Fürst (1960-1972). Der Beitrag skizziert die Statistischen Wochen, die Tätigkeit der Ausschüsse und die Veröffentlichungen in dieser Zeit.

  9. Der Strahlenkranz im sonnigen Wasser

    NASA Astrophysics Data System (ADS)

    Schlichting, Hans Joachim

    2000-01-01

    Wie in der Kunst gibt es auch in der Natur neben dem kreisförmigen Heiligenschein einen strahlenförmigen Nimbus um den Kopfschatten "auserwählter" Personen. Er ist in leicht getrübtem Wasser zu beobachten.

  10. Entwicklungsperspektiven von Social Software und dem Web 2.0

    NASA Astrophysics Data System (ADS)

    Raabe, Alexander

    Der Artikel beschäftigt sich zunächst mit dem derzeitigen und zukünftigen Einsatz von Social Software in Unternehmen. Nach dem großen Erfolg von Social Software im Web beginnen viele Unternehmen eigene Social Software-Initiativen zu entwickeln. Der Artikel zeigt die derzeit wahrgenommenen Einsatzmöglichkeiten von Social Software im Unternehmen auf, erörtert Erfolgsfaktoren für die Einführung und präsentiert mögliche Wege für die Zukunft. Nach der Diskussion des Spezialfalles Social Software in Unternehmen werden anschließend die globalen Trends und Zukunftsperspektiven des Web 2.0 in ihren technischen, wirtschaftlichen und sozialen Dimensionen dargestellt. Wie aus den besprochenen Haupttrends hervorgeht, wird die Masse an digital im Web verfügbaren Informationen stetig weiterwachsen. So stellt sich die Frage, wie es in Zukunft möglich sein wird, die Qualität der Informationssuche und der Wissensgenerierung zu verbessern. Mit dem Einsatz von semantischen Technologien im Web wird hier eine revolutionäre Möglichkeit geboten, Informationen zu filtern und intelligente, gewissermaßen verstehende" Anwendungen zu entwerfen. Auf dem Weg zu einem intelligenten Web werden sich das Semantic Web und Social Software annähern: Anwendungen wie Semantic Wikis, Semantic Weblogs, lightweight Semantic Web-Sprachen wie Microformats oder auch kommerzielle Angebote wie Freebase von Metaweb werden die ersten Vorzeichen einer dritten Generation des Webs sein.

  11. Datenqualitäts-Modell der Volkswagen Financial Services AG

    NASA Astrophysics Data System (ADS)

    Moser, Helena

    Im Rahmen der Vertriebsaktivitäten und der umfangreichen rechtlichen und regulatorischen Anforderungen u. a. Basel II hat die Volkswagen Financial Services AG (nachfolgend VW FS AG) beschlossen, dem Thema Datenqualität und Datenqualitätsmanagement, insbesondere unter dem Blickwinkel der Konzern Leitlinien Kundennähe, Schaffung von Werten und Höchstleistung, eine hohe Priorität einzuräumen.

  12. ASTER DEM performance

    USGS Publications Warehouse

    Fujisada, H.; Bailey, G.B.; Kelly, Glen G.; Hara, S.; Abrams, M.J.

    2005-01-01

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument onboard the National Aeronautics and Space Administration's Terra spacecraft has an along-track stereoscopic capability using its a near-infrared spectral band to acquire the stereo data. ASTER has two telescopes, one for nadir-viewing and another for backward-viewing, with a base-to-height ratio of 0.6. The spatial resolution is 15 m in the horizontal plane. Parameters such as the line-of-sight vectors and the pointing axis were adjusted during the initial operation period to generate Level-1 data products with a high-quality stereo system performance. The evaluation of the digital elevation model (DEM) data was carried out both by Japanese and U.S. science teams separately using different DEM generation software and reference databases. The vertical accuracy of the DEM data generated from the Level-1A data is 20 m with 95% confidence without ground control point (GCP) correction for individual scenes. Geolocation accuracy that is important for the DEM datasets is better than 50 m. This appears to be limited by the spacecraft position accuracy. In addition, a slight increase in accuracy is observed by using GCPs to generate the stereo data. ?? 2005 IEEE.

  13. Discrete Element Modeling (DEM) of Triboelectrically Charged Particles: Revised Experiments

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Calle, Carlos I.; Curry, D. R.; Weitzman, P. S.

    2008-01-01

    In a previous work, the addition of basic screened Coulombic electrostatic forces to an existing commercial discrete element modeling (DEM) software was reported. Triboelectric experiments were performed to charge glass spheres rolling on inclined planes of various materials. Charge generation constants and the Q/m ratios for the test materials were calculated from the experimental data and compared to the simulation output of the DEM software. In this paper, we will discuss new values of the charge generation constants calculated from improved experimental procedures and data. Also, planned work to include dielectrophoretic, Van der Waals forces, and advanced mechanical forces into the software will be discussed.

  14. Jahr der Geowissenschaften

    NASA Astrophysics Data System (ADS)

    Wohnlich, Stefan

    2002-06-01

    Das System Erde ist Leitthema des "Jahres der Geowissenschaften", das von der Bundesministerin für Bildung und Forschung in den Vordergrund der Initiative "Wissenschaft im Dialog" für 2002 gestellt wurde. Es soll aufzeigen, dass wir in einer empfindlichen Umwelt leben, die auf die natürlichen Schwankungen, z. B. des Klimas, genauso empfindlich reagiert wie auf die rücksichtslose Nutzung der Erde durch den Menschen. Damit rückt auch das Thema Grundwasser als Teil des globalen Wasserkreislaufes in den Mittelpunkt der derzeitigen Öffentlichkeitsarbeit. Wenn wir uns die bisherige Resonanz auf das Jahr der Geowissenschaften anschauen, dann ist festzustellen, dass gerade die Bereitschaft aus den Medien zur Aufnahme von Geowissenschaftlichen Themen erstaunlich groß ist. Aus dem Bereich des Grund- und Trinkwassers snd vor allem in Universitätsstädten bereits größere Veranstaltungen durchgeführt worden oder stehen noch im Laufe des Jahres aus (Information unter: www.planeterde.de). Tatsächlich ist der Dialog von Wissenschaft und Praxis mit der Öffentlichkeit ein vorrangiges Ziel auch der Fachsektion Hydrogeologie. Nur allzu leicht tritt dieses Ziel im Alltagsbetrieb in den Hintergrund. Die deutschen Universitäten und Wissenschaftsorganisationen haben in die Öffentlichkeitsarbeit erst in den letzten Jahren verstärkt Ideen und Mittel investiert. Dabei ist gerade das Verständnis für die Chancen und Risiken der Forschung und damit auch der Hochschullehre in der breiten Öffentlichkeit eine unabdingbare Voraussetzung. Aber nicht nur die wissenschaftliche Organisationen sind auf die Akzeptanz einer breiten Öffentlichkeit für wissenschaftlich fundiertes Arbeiten angewiesen, sondern auch die von Fachwissen geprägten Aufgaben im Umfeld des Grundwassers brauchen das Verständnis für ihre oft aufwändigen Untersuchungen. Ich habe in den letzten Monaten mehrere Vorträge an verschiedenen Gymnasien zum Thema "Ressource Grundwasser" gehalten. Die Resonanz war f

  15. Akteure in der Renaturierung

    NASA Astrophysics Data System (ADS)

    Wiegleb, Gerhard; Lüderitz, Volker

    Dieses Kapitel behandelt die Bedeutung von Akteuren in Renaturierungsprojekten. Renaturierung ist die absichtliche Veränderung der Umwelt in Richtung auf einen von den Akteuren als "naturnäher“ erachteten Zustand (Kapitel 1). Betroffen davon ist nicht nur die Umwelt der Akteure, sondern auch die Umwelt anderer. Daraus ergeben sich sowohl aktive wie passive Bezüge zur Renaturierung. Aktive und passive Rollen sind je nach Ausdehnung, Zeithorizont und Trägerschaft nicht immer trennbar, sodass die Unterscheidung in Akteure und Betroffene nur begrenzte Gültigkeit hat. Methodisch basiert die Untersuchung der Teilhabe an Renaturierung auf Akteurs- und Akzeptanzanalysen (vgl. Segert und Zierke 2004, Newig 2004). Die vorliegenden Ausführungen befassen sich schwerpunktmäßig mit dem Aspekt der Akteursanalyse. Die Frage der Akzeptanz wird kurz angesprochen (Kapitel 15, Umweltethische Aspekte). Anhand der Analyse zweier Fallstudien werden dann einige Schlussfolgerungen gezogen. Die Darstellung soll im Wesentlichen das Feld für zukünftig nötige Forschungsarbeiten strukturieren.

  16. Werner Heisenberg zum 100. Geburtstag: Pionier der Quantenmechanik

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2001-11-01

    Werner Heisenberg war eine der prägendsten Gestalten der Physik des 20. Jahrhunderts. Zu seinen wichtigsten Verdiensten gehören die Grundlegung der Quantenmechanik, die Formulierung der Unschärferelationen sowie die Beteiligung an der Ausarbeitung der Kopenhagener Deutung der Quantenmechanik. Darüber hinaus lieferte er Arbeiten von fundamentalem Charakter zur Theorie des Atomkerns, zur kosmischen Strahlung und zur Quantenfeldtheorie. Während des Krieges war er an den Arbeiten des Uranvereins beteiligt, der die Möglichkeit einer Entwicklung von Kernwaffen untersuchte, jedoch über Vorarbeiten zur Reaktorphysik nicht hinauskam. Wegen dieser Tätigkeit wurde er bei Kriegsende für einige Monate in England interniert. Nach seiner Rückkehr widmete er sich vor allem dem Aufbau der Physik in Deutschland, die während der NS-Zeit nahezu ihrer gesamten Substanz beraubt worden war.

  17. TanDEM-X calibrated Raw DEM generation

    NASA Astrophysics Data System (ADS)

    Rossi, Cristian; Rodriguez Gonzalez, Fernando; Fritz, Thomas; Yague-Martinez, Nestor; Eineder, Michael

    2012-09-01

    The TanDEM-X mission successfully started on June 21st 2010 with the launch of the German radar satellite TDX, placed in orbit in close formation with the TerraSAR-X (TSX) satellite, and establishing the first spaceborne bistatic interferometer. The processing of SAR raw data to the Raw DEM is performed by one single processor, the Integrated TanDEM-X Processor (ITP). The quality of the Raw DEM is a fundamental parameter for the mission planning. In this paper, a novel quality indicator is derived. It is based on the comparison of the interferometric measure, the unwrapped phase, and the stereo-radargrammetric measure, the geometrical shifts computed in the coregistration stage. By stating the accuracy of the unwrapped phase, it constitutes a useful parameter for the determination of problematic scenes, which will be resubmitted to the dual baseline phase unwrapping processing chain for the mitigation of phase unwrapping errors. The stereo-radargrammetric measure is also operationally used for the Raw DEM absolute calibration through an accurate estimation of the absolute phase offset. This paper examines the interferometric algorithms implemented for the operational TanDEM-X Raw DEM generation, focusing particularly on its quality assessment and its calibration.

  18. Materialbereitstellung in der Montage

    NASA Astrophysics Data System (ADS)

    Nyhuis, Peter; Wiendahl, Hans-Peter; Fiege, Torsten; Mühlenbruch, Helge

    Die Montage verarbeitet eine sehr große Anzahl unterschiedlicher Teile und Baugruppen in zahlreichen Varianten. Sie müssen mit hoher Zuverläs-sigkeit am richtigen Ort zur richtigen Zeit in der richtigen Qualität and zu den richtigen Kosten bereit stehen. Im Gegensatz zum Ausgangsmaterial in einer Fertigung sind sie funktionsfähig and damit meist empfindlich. Bevor sie an einer Montageeinrichtung eintreffen, sind auf dem Wege vom Hersteller zum Verbauort drei unterschiedliche Abschnitte zu erkennen, die von unterschiedlichen inner- und außerbetrieblichen Akteuren geplant, durchgeführt and überwacht werden.

  19. Hydrologic enforcement of lidar DEMs

    USGS Publications Warehouse

    Poppenga, Sandra K.; Worstell, Bruce B.; Danielson, Jeffrey J.; Brock, John C.; Evans, Gayla A.; Heidemann, H. Karl

    2014-01-01

    Hydrologic-enforcement (hydro-enforcement) of light detection and ranging (lidar)-derived digital elevation models (DEMs) modifies the elevations of artificial impediments (such as road fills or railroad grades) to simulate how man-made drainage structures such as culverts or bridges allow continuous downslope flow. Lidar-derived DEMs contain an extremely high level of topographic detail; thus, hydro-enforced lidar-derived DEMs are essential to the U.S. Geological Survey (USGS) for complex modeling of riverine flow. The USGS Coastal and Marine Geology Program (CMGP) is integrating hydro-enforced lidar-derived DEMs (land elevation) and lidar-derived bathymetry (water depth) to enhance storm surge modeling in vulnerable coastal zones.

  20. Tycho Brahe - Instrumentenbauer und Meister der Beobachtungstechnik

    NASA Astrophysics Data System (ADS)

    Wolfschmidt, Gudrun

    Vor der Erfindung des Fernrohrs war der dänische Astronom Tycho Brahe (1546 - 1601) der bedeutendste beobachtende Astronom. Von seinem Observatorium Uraniborg auf der - damals dänischen - Insel Hven ist heute noch der Grundriß erkennbar, von Stjerneborg sind die Fundamente erhalten, die Kuppeln in den 1950er Jahren ergänzt. In der Astronomie-Ausstellung im Deutschen Museum gibt es ein Modell der Sternwarte Uraniborg und der zugehörigen Instrumente (Maßstab 1:10); das größere Modell wurde dem Technischen Museum in Malmö geschenkt. Die Instrumente, die er in den Observatorien Uraniborg und Stjerneborg benutzte, sind nicht erhalten. Aber es gibt gute Beschreibungen der Instrumente (Halbkreis, Quadranten, Sextanten, Armillarsphären, Triquetrum, Himmelsglobus) in seinem Buch Astronomiae instauratae mechanica (Wandsbek 1598). Eine Nachbildung des großen hölzernen Quadranten kann man im Runden Turm in Kopenhagen sehen. Zwei Sextanten, hergestellt für Tycho um 1600 von Jost Bürgi und Erasmus Habermel, gibt es noch im Nationalmuseum für Technik in Prag. Ähnlichkeiten von Tychos Instrumenten mit Groß-Instrumenten aus dem islamischen Kulturkreis sind auffällig. Tycho Brahes Meßgeräte markieren einen großen Fortschritt in der Entwicklung astronomischer Instrumente und Meßtechniken und bilden die Grundlage für den weiteren Fortschritt der Positionsastronomie und der damit verbundenen Tabellenwerke. Die Nachwirkungen sind bis ins 17. und 18. Jahrhundert nachweisbar.

  1. Symmetriebrechung und Emergenz in der Kosmologie.

    NASA Astrophysics Data System (ADS)

    Mainzer, K.

    Seit der Antike wird der Aufbau des Universums mit einfachen und regulären (symmetrischen) Grundstrukturen verbunden. Diese Annahme liegt selbst noch den Standardmodellen der relativistischen Kosmologie zugrunde. Demgegenüber läßt sich die Emergenz neuer Strukturen von den Elementarteilchen über Moleküle bis zu den komplexen Systemen des Lebens als Symmetriebrechung verstehen. Symmetriebrechung und strukturelle Komplexität bestimmen die kosmische Evolution. Damit zeichnet sich ein fachübergreifendes Forschungsprogramm von Physik, Chemie und Biologie ab, in dem die Evolution des Universums untersucht werden kann.

  2. Radar and Lidar Radar DEM

    NASA Technical Reports Server (NTRS)

    Liskovich, Diana; Simard, Marc

    2011-01-01

    Using radar and lidar data, the aim is to improve 3D rendering of terrain, including digital elevation models (DEM) and estimates of vegetation height and biomass in a variety of forest types and terrains. The 3D mapping of vegetation structure and the analysis are useful to determine the role of forest in climate change (carbon cycle), in providing habitat and as a provider of socio-economic services. This in turn will lead to potential for development of more effective land-use management. The first part of the project was to characterize the Shuttle Radar Topography Mission DEM error with respect to ICESat/GLAS point estimates of elevation. We investigated potential trends with latitude, canopy height, signal to noise ratio (SNR), number of LiDAR waveform peaks, and maximum peak width. Scatter plots were produced for each variable and were fitted with 1st and 2nd degree polynomials. Higher order trends were visually inspected through filtering with a mean and median filter. We also assessed trends in the DEM error variance. Finally, a map showing how DEM error was geographically distributed globally was created.

  3. Jahre Entwicklung der Instandhaltung - von der ausfallorientierten Instandhaltung zum gemeinsamen TPM und RCM

    NASA Astrophysics Data System (ADS)

    Iske, Friedhelm

    Zur Einleitung meines Beitrages möchte ich von einem Gespräch mit einem Mitarbeiter berichten, das ich als junger Vorgesetzter einer Instandhaltungsgruppe 1988 führte. Der engagierte Mitarbeiter feierte damals sein vierzigjähriges Dienstjubiläum und war stolz auf das von ihm Geleistete sowie auf den besonderen Einsatz seiner Altersgruppe, die nach dem Zweiten Weltkrieg das Werk wieder aufgebaut hatte. Auf meine Frage, was denn damals die erste Aufgabe in der Firma war, bekam ich kurz und knapp und mit einer Selbstverständlichkeit die selbstbewusste Antwort: "Unser Pferd füttern und mit dem Pferd die innerbetrieblichen Transporte erledigen“. Als junger, technisch orientierter Vorgesetzter war ich über diese Antwort sehr überrascht. Gedanklich weit entfernt war die Vorstellung, dass in der Vergangenheit Transporte mit einem Pferd erledigt wurden.

  4. Chirurgische Behandlung von Melanomen in der Schwangerschaft: eine praktische Anleitung.

    PubMed

    Crisan, Diana; Treiber, Nicolai; Kull, Thomas; Widschwendter, Peter; Adolph, Oliver; Schneider, Lars Alexander

    2016-06-01

    Als ein Tumor, der primär eine chirurgische Behandlung erfordert, ist ein neu diagnostiziertes oder vorbestehendes Melanom in der Schwangerschaft eine klinische Rarität. In solchen Fällen steht der Chirurg vor der Herausforderung, ein geeignetes therapeutisches Vorgehen festlegen zu müssen. Auf der Grundlage unserer klinischen Erfahrung und einer Übersicht über die Literatur geben wir in der vorliegenden Arbeit eine Anleitung für das praktische Vorgehen bei dieser seltenen klinischen Konstellation. Unserer Erfahrung nach müssen schwangere Melanom-Patientinnen im Hinblick auf ihre therapeutischen Optionen ausführlich beraten werden. Naturgemäß setzen sie ihr ungeborenes Kind an die erste Stelle und zögern, der erforderlichen Operation zuzustimmen, obwohl bei ihnen eine möglicherweise lebensbedrohliche Erkrankung diagnostiziert worden ist. Daher ist es entscheidend, diese Patientinnen klar darüber zu informieren, dass, wie die vorliegenden medizinischen Erfahrungen zeigen, eine Schwangerschaft per se kein Grund ist, eine notwendige Melanom-Operation aufzuschieben. Jedoch müssen bei einigen Parametern wie den präoperativen Bildgebungsverfahren, der Positionierung auf dem Operationstisch, der Überwachung, Anästhesie und der perioperativen Medikation bestimmte Anpassungen vorgenommen werden, um der speziellen Situation Rechnung zu tragen. PMID:27240063

  5. Convolutional Neural Network Based dem Super Resolution

    NASA Astrophysics Data System (ADS)

    Chen, Zixuan; Wang, Xuewen; Xu, Zekai; Hou, Wenguang

    2016-06-01

    DEM super resolution is proposed in our previous publication to improve the resolution for a DEM on basis of some learning examples. Meanwhile, the nonlocal algorithm is introduced to deal with it and lots of experiments show that the strategy is feasible. In our publication, the learning examples are defined as the partial original DEM and their related high measurements due to this way can avoid the incompatibility between the data to be processed and the learning examples. To further extent the applications of this new strategy, the learning examples should be diverse and easy to obtain. Yet, it may cause the problem of incompatibility and unrobustness. To overcome it, we intend to investigate a convolutional neural network based method. The input of the convolutional neural network is a low resolution DEM and the output is expected to be its high resolution one. A three layers model will be adopted. The first layer is used to detect some features from the input, the second integrates the detected features to some compressed ones and the final step transforms the compressed features as a new DEM. According to this designed structure, some learning DEMs will be taken to train it. Specifically, the designed network will be optimized by minimizing the error of the output and its expected high resolution DEM. In practical applications, a testing DEM will be input to the convolutional neural network and a super resolution will be obtained. Many experiments show that the CNN based method can obtain better reconstructions than many classic interpolation methods.

  6. Einsteins Spuren in den Archiven der Wissenschaft: Physikgeschichte

    NASA Astrophysics Data System (ADS)

    Marx, Werner

    2005-07-01

    Die Erwähnungen und Zitierungen von Einsteins Arbeiten dokumentieren lediglich den quantifizierbaren Anteil von Einsteins Beitrag zur Physik. Gleichwohl belegen sie die außergewöhnliche Resonanz und Langzeitwirkung seiner Arbeiten. Die Häufigkeit der Zitierungen entspricht nicht der allgemeinen Einschätzung ihrer Bedeutung. Insbesondere die Pionierarbeiten werden inzwischen als bekannt vorausgesetzt und nicht mehr explizit zitiert. Interessanterweise ist seine nach 1945 meist zitierte Arbeit nicht eine der Pionierarbeiten zur Quantenphysik oder Relativitätstheorie, sondern jene aus dem Jahr 1935 zum berühmten Einstein-Podolsky-Rosen-Paradoxon.

  7. A Comparison of Elevation Between InSAR DEM and Reference DEMs

    NASA Astrophysics Data System (ADS)

    Yun, Ye; Zeng, Qiming; Jiao, Jian; Yan, Dapeng; Liang, Cunren; Wang, Qing; Zhou, Xiao

    2013-01-01

    Introduction (1) DEM generation Space borne SAR interferometry is one of the methods for the generation of digital elevation model (DEM). (2) Common methods to generate DEMs • Same antenna with two passes: e.g. ERS1/2 • Single-pass interferometry : e.g. SRTM • Geometry of stereopairs : e.g. SPOT and ASTER • Combination of air-photograph, satellite image, topographic map and field measurement : e.g. NGCC (National Geomatics Center of China, which has completed the establishment of 1:50000 topographic databases of China) (3) Purpose of this study Compare DEMs derived from ERS1/2 and common methods by comparison of tandem and reference DEMs which are SRTM DEM, ASTER GDEM and NGCC DEM. Some qualitative and quantitative assessments of the elevation were used to estimate the difference.

  8. TanDEM-X high resolution DEMs and their applications to flow modeling

    NASA Astrophysics Data System (ADS)

    Wooten, Kelly M.

    Lava flow modeling can be a powerful tool in hazard assessments; however, the ability to produce accurate models is usually limited by a lack of high resolution, up-to-date Digital Elevation Models (DEMs). This is especially obvious in places such as Kilauea Volcano (Hawaii), where active lava flows frequently alter the terrain. In this study, we use a new technique to create high resolution DEMs on Kilauea using synthetic aperture radar (SAR) data from the TanDEM-X (TDX) satellite. We convert raw TDX SAR data into a geocoded DEM using GAMMA software [Werner et al., 2000]. This process can be completed in several hours and permits creation of updated DEMs as soon as new TDX data are available. To test the DEMs, we use the Harris and Rowland [2001] FLOWGO lava flow model combined with the Favalli et al. [2005] DOWNFLOW model to simulate the 3-15 August 2011 eruption on Kilauea's East Rift Zone. Results were compared with simulations using the older, lower resolution 2000 SRTM DEM of Hawaii. Effusion rates used in the model are derived from MODIS thermal infrared satellite imagery. FLOWGO simulations using the TDX DEM produced a single flow line that matched the August 2011 flow almost perfectly, but could not recreate the entire flow field due to the relatively high DEM noise level. The issues with short model flow lengths can be resolved by filtering noise from the DEM. Model simulations using the outdated SRTM DEM produced a flow field that followed a different trajectory to that observed. Numerous lava flows have been emplaced at Kilauea since the creation of the SRTM DEM, leading the model to project flow lines in areas that have since been covered by fresh lava flows. These results show that DEMs can quickly become outdated on active volcanoes, but our new technique offers the potential to produce accurate, updated DEMs for modeling lava flow hazards.

  9. Kommunikationsanforderungen an verteilte Echtzeitsysteme in der Fertigungsautomatisierung

    NASA Astrophysics Data System (ADS)

    Just, Roman; Trsek, Henning

    Kommunikationssysteme der Automatisierung müssen hohe zeitliche Anforderungen erfüllen, damit die entsprechenden industriellen Anwendungen realisiert werden können. Im Gegensatz zum IT-Bereich sind diese Anforderungen jedoch häufig nicht genau bekannt, was insbesondere beim Einsatz von drahtlosen Technologien Probleme bereiten kann1. In dieser Arbeit werden Verkehrsmuster einer realen Anlage aus dem Bereich der Fertigungsautomatisierung bestimmt. Die Zwischenankunfts- und Latenzzeiten einzelner Sensorund Aktorsignale ermöglichen Rückschlüsse auf zeitliche Anforderungen und Charakteristiken der untersuchten Anwendung. Im Anschluss werden die erzielten Erkenntnisse hinsichtlich ausgewählter Kommunikationsanforderungen analysiert und aktuell gültige Anforderungen von realen Automatisierungsanlagen abgeleitet. Weiterhin werden sie zukünftig zur Entwicklung realitätsnaher Simulationsmodelle genutzt.

  10. Urban DEM generation, analysis and enhancements using TanDEM-X

    NASA Astrophysics Data System (ADS)

    Rossi, Cristian; Gernhardt, Stefan

    2013-11-01

    This paper analyzes the potential of the TanDEM-X mission for the generation of urban Digital Elevation Models (DEMs). The high resolution of the sensors and the absence of temporal decorrelation are exploited. The interferometric chain and the problems encountered for correct mapping of urban areas are analyzed first. The operational Integrated TanDEM-X Processor (ITP) algorithms are taken as reference. The ITP main product is called the raw DEM. Whereas the ITP coregistration stage is demonstrated to be robust enough, large improvements in the raw DEM such as fewer percentages of phase unwrapping errors, can be obtained by using adaptive fringe filters instead of the conventional ones in the interferogram generation stage. The shape of the raw DEM in the layover area is also shown and determined to be regular for buildings with vertical walls. Generally, in the presence of layover, the raw DEM exhibits a height ramp, resulting in a height underestimation for the affected structure. Examples provided confirm the theoretical background. The focus is centered on high resolution DEMs produced using spotlight acquisitions. In particular, a raw DEM over Berlin (Germany) with a 2.5 m raster is generated and validated. For this purpose, ITP is modified in its interferogram generation stage by adopting the Intensity Driven Adaptive Neighbourhood (IDAN) algorithm. The height Root Mean Square Error (RMSE) between the raw DEM and a reference is about 8 m for the two classes defining the urban DEM: structures and non-structures. The result can be further improved for the structure class using a DEM generated with Persistent Scatterer Interferometry. A DEM fusion is thus proposed and a drop of about 20% in the RMSE is reported.

  11. Vollautomatische Segmentierung der Prostata aus 3D-Ultraschallbildern

    NASA Astrophysics Data System (ADS)

    Heimann, Tobias; Simpfendörfer, Tobias; Baumhauer, Matthias; Meinzer, Hans-Peter

    Diese Arbeit beschreibt ein modellbasiertes Verfahren zur Segmentierung der Prostata aus 3D-Ultraschalldaten. Kern der Methode ist ein statistisches Formmodell, das auf Beispieldaten der Prostata trainiert wird. Erster Schritt der Segmentierung ist ein evolutionärer Algorithmus, mit dem das Modell grob im zu segmentierenden Bild positioniert wird. Für die darauf folgende lokale Suche wurden mehrere Varianten des Algorithmus evaluiert, unter anderem Ausreißer-Unterdrückung, freie Deformation und Gewichtung der verwendeten Erscheinungsmodelle nach ihrer Zuverlässigkeit. Alle Varianten wurden auf 35 Ultraschallbildern getestet und mit manuellen Referenzsegmentierungen verglichen. Die beste Variante erreichte eine durchschnittliche Oberflächenabweichung von 1.1 mm.

  12. elecTUM: Umsetzung der eLearning-Strategie der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Rathmayer, Sabine; Gergintchev, Ivan

    An der TUM wurde ein umfassendes und integriertes eLearning-Konzept umgesetzt, welches Präsenzstudium und eLearning in allen Leistungsbereichen der Universität miteinander verzahnt. Ein besonderer Schwerpunkt lag dabei in der Schaffung einer effizienten und wettbewerbsfähigen integrierten eLearning Infrastruktur in Hinblick auf die noch weiter steigenden Studienanfängerzahlen ab dem Jahr 2011 sowie die Umsetzung von eBologna. Die Etablierung einer hochschulweiten Lernplattform stellte eine wesentliche Basis für die Umsetzung der eLearning-Strategie dar. Die wissenschaftliche und wirtschaftliche Anschlussfähigkeit im Hinblick auf eine Verwertung der Projektergebnisse wurde durch die aktive Beteiligung an einer Vielzahl hochschulübergreifender Arbeitskreise, Fachtagungen und Kooperationen, vor allem über Organisations- und Dienstleistungsmodelle sowie innovative technische Entwicklungen, sichergestellt.

  13. Nonlocal similarity based DEM super resolution

    NASA Astrophysics Data System (ADS)

    Xu, Zekai; Wang, Xuewen; Chen, Zixuan; Xiong, Dongping; Ding, Mingyue; Hou, Wenguang

    2015-12-01

    This paper discusses a new topic, DEM super resolution, to improve the resolution of an original DEM based on its partial new measurements obtained with high resolution. A nonlocal algorithm is introduced to perform this task. The original DEM was first divided into overlapping patches, which were classified either as "test" or "learning" data depending on whether or not they are related to high resolution measurements. For each test patch, the similar patches in the learning dataset were identified via template matching. Finally, the high resolution DEM of the test patch was restored by the weighted sum of similar patches under the condition that the reconstruction weights were the same in different resolution cases. A key assumption of this strategy is that there are some repeated or similar modes in the original DEM, which is quite common. Experiments were done to demonstrate that we can restore a DEM by preserving the details without introducing artifacts. Statistic analysis was also conducted to show that this method can obtain higher accuracy than traditional interpolation methods.

  14. Quality Test Various Existing dem in Indonesia Toward 10 Meter National dem

    NASA Astrophysics Data System (ADS)

    Amhar, Fahmi

    2016-06-01

    Indonesia has various DEM from many sources and various acquisition date spreaded in the past two decades. There are DEM from spaceborne system (Radarsat, TerraSAR-X, ALOS, ASTER-GDEM, SRTM), airborne system (IFSAR, Lidar, aerial photos) and also terrestrial one. The research objective is the quality test and how to extract best DEM in particular area. The method is using differential GPS levelling using geodetic GPS equipment on places which is ensured not changed during past 20 years. The result has shown that DEM from TerraSAR-X and SRTM30 have the best quality (rmse 3.1 m and 3.5 m respectively). Based on this research, it was inferred that these parameters are still positively correlated with the basic concept, namely that the lower and the higher the spatial resolution of a DEM data, the more imprecise the resulting vertical height.

  15. Quantenphysikalischer Ursprung der Eichidee

    NASA Astrophysics Data System (ADS)

    Bopp, Fritz

    Betrachtet man die Quantenphysik als Zusammenspiel von elementaren Erzeugungs- und Vernichtungsprozessen, so sind Eichfeldtheorien nicht nur möglich, sondern auch notwendig. Die komplex konjugierten Phasenfaktoren jedes Paares von Erzeugungs- und Vernichtungsoperatoren sind nämlich. willkürlich wählbar. Darum müssen Quantenfeldtheorien vollständig phaseninvariant sein. Das ist ohne Eichfelder nicht möglich.Dem steht im Wege, daß die Diracgleichung nicht einmal global vollständig phaseninvariant ist. Multipliziert man nämlich die Komponenten der Erzeugungs- und Vernichtungsoperatoren mit verschiedenen konstanten Phasenfaktoren, so ändern sich die Diracmatrizen. Nur die Diracschen Vertauschungsrelationen bleiben invariant. Doch sind die Diracgleichungen vor und nach der Transformation physikalisch äquivalent. Man kann also sagen: Systeme freier Fermionen werden erst durch die Klasse aller äquivalenten Diracgleichungen vollständig dargestellt.Da die Diracschen Vertauschungsrelationen gegen beliebige unitäre Transformationen invariant sind, ist die Klasse äquivalenter Diracgleichungen U 4-invariant. Unitäre Diagonalmatrizen liefern willkürliche Phasentransformationen der Spinorkomponenten, so daß die zur Gruppe U 4 gehörigen Eichfelder zu eine allgemein phaseninvarianten Theorie führen. Sie ist so eng mit der QED verwandt, daß wir von einer erweiterten Quantenelektrodynamik, EQE, sprechen können.Hier soll nur gezeigt werden, daß die EQE existiert. Dabei liefert die invariante Untergruppe U 1 von U 4 die QED. Die komplementäre Untergruppe SU 4 umschließt vier Untergruppen SU 3, drei Untergruppen O 4 und sechs Untergruppen SU 2. Letztere könnten den drei Paaren von Quarks und den drei Paaren von Leptonen entsprechen, wobei sich die Quarkpaare zu einer Gruppe SU 3 zusammenschließen. Mehr als zweimal drei Paare von elementaren Fermionen gibt es in der EQE nicht. Sie wird zwar kaum mit der vereinigten QED und QCD identisch sein. Doch sollte sie

  16. Skeletonizing a DEM into a drainage network

    NASA Astrophysics Data System (ADS)

    Meisels, Amnon; Raizman, Sonia; Karnieli, Arnon

    1995-02-01

    A new method for extracting drainage systems from Digital Elevation Models (DEMs) is presented. The main algorithm of the proposed method performs a skeletonization process of the set of elevations in the DEM and produces a skeleton of flow paths. An enumeration algorithm performs the removal of loops from the initial flow path. A preprocess for filling depressions is described as is the necessary postprocessing for determining the drainage network through depressions. The new method does not suffer from any of the maladies of former methods described in the literature, such as flow cutoffs, loops of flow, and basin flooding. The new method is tested on several real-world DEMs and produced connected, complete, and loopless networks.

  17. Umsetzung der Unternehmensstrategie mit der Balanced Scorecard

    NASA Astrophysics Data System (ADS)

    Crespo, Isabel; Bergmann, Lars; Portmann, Stefan; Lacker, Thomas; Lacker, Michael; Fleischmann, Jürgen; Kozó, Hans

    Die Balanced Scorecard (BSC) ist ein Ansatz zum strategischen Management, der neben der Ausrichtung des Unternehmens auf finanzielle Zielwerte ebenso großes Gewicht auf so genannte weiche Faktoren legt, die den wirtschaftlichen Erfolg eines Unternehmens erst ermöglichen. Das entscheidende Merkmal der Balanced Scorecard ist dabei, dass sie ein ausgewogenes System strategischer Ziele herstellt, welches das Unternehmen hinsichtlich der vier Perspektiven Finanzen, Kunden, interne Prozesse und Mitarbeiter und Potenziale strategisch ausrichtet (Kaplan u. Norton 1997).

  18. Kanban - der Weg ist das Ziel

    NASA Astrophysics Data System (ADS)

    Aull, Florian; Berlak, Joachim; Dickmann, Eva; Dickmann, Philipp; Fischäder, Holm; Gerlach, Joachim; Henneberg, Jens; Kapalla, Klaus; Kress, Oliver; Kuttler, Robert; Schneider, Herfried M.; Schürle, Philipp; Stellpflug, Franz-Josef; Wannenwetsch, Ralph; Wulz, Johannes; Zäh, Michael F.

    Wenn man aktuell Produktionsbereiche in Deutschland und Europa besucht, fallen im Zusammenhang mit modernen Produktionsmethoden immer öfter die Begriffe Kanban (jap. Karte, Signal) und Pull-Produktion, und dies nicht ohne Stolz, da diese mit dem schillernden Vorbild des Toyota Produktionssystems in Zusammenhang stehen. Tatsächlich ist Kanban ein integraler Bestandteil moderner Produktionssysteme. Blickt man aber im Rahmen von Prozessanalysen hinter die Fassaden", d. h. in die tägliche Praxis der Arbeitsprozesse, wird man schnell desillusioniert - die viel gepriesenen klassischen Kanban-Regeln werden im Tagesgeschäft nicht eingehalten.

  19. Zu einer inhaltsorientierten Theorie des Lernens und Lehrens der biologischen Evolution

    NASA Astrophysics Data System (ADS)

    Wallin, Anita

    Der Zweck dieser Studie (zwecks Überblick siehe dazu Abb. 9.1) war zu untersuchen, wie die Schüler der Sekundarstufe II ein Verständnis von der Theorie der biologischen Evolution entwickeln. Vom Ausgangspunkt "Vorurteile der Schüler“ ausgehend wurden Unterrichtssequenzen entwickelt und drei verschiedene Lernexperimente in einem zyklischen Prozess durchgeführt. Das Wissen der Schüler wurde vor, während und nach den Unterrichtssequenzen mit Hilfe von schriftlichen Tests, Interviews und Diskussionsrunden in kleinen Gruppen abgefragt. Etwa 80 % der Schüler hatten vor dem Unterricht alternative Vorstellungen von Evolution, und in dem Nachfolgetest erreichten circa 75 % ein wissenschaftliches Niveau. Die Argumentation der Schüler in den verschiedenen Tests wurde sorgfältig unter Rücksichtnahme auf Vorurteile, der konzeptionellen Struktur der Theorie der Evolution und den Zielen des Unterrichts analysiert. Daraus konnten Einsichten in solche Anforderungen an Lehren und Lernen gewonnen werden, die Herausforderungen an Schüler und Lehrer darstellen, wenn sie anfangen, evolutionäre Biologie zu lernen oder zu lehren. Ein wichtiges Ergebnis war, dass das Verständnis existierender Variation in einer Population der Schlüssel zum Verständnis von natürlicher Selektion ist. Die Ergebnisse sind in einer inhaltsorientierten Theorie zusammengefasst, welche aus drei verschiedenen Aspekten besteht: 1) den inhaltsspezifischen Aspekten, die einzigartig für jedes wissenschaftliche Feld sind; 2) den Aspekten, die die Natur der Wissenschaft betreffen; und 3) den allgemeinen Aspekten. Diese Theorie kann in neuen Experimenten getestet und weiter entwickelt werden.

  20. Statistic Tests Aided Multi-Source dem Fusion

    NASA Astrophysics Data System (ADS)

    Fu, C. Y.; Tsay, J. R.

    2016-06-01

    Since the land surface has been changing naturally or manually, DEMs have to be updated continually to satisfy applications using the latest DEM at present. However, the cost of wide-area DEM production is too high. DEMs, which cover the same area but have different quality, grid sizes, generation time or production methods, are called as multi-source DEMs. It provides a solution to fuse multi-source DEMs for low cost DEM updating. The coverage of DEM has to be classified according to slope and visibility in advance, because the precisions of DEM grid points in different areas with different slopes and visibilities are not the same. Next, difference DEM (dDEM) is computed by subtracting two DEMs. It is assumed that dDEM, which only contains random error, obeys normal distribution. Therefore, student test is implemented for blunder detection and three kinds of rejected grid points are generated. First kind of rejected grid points is blunder points and has to be eliminated. Another one is the ones in change areas, where the latest data are regarded as their fusion result. Moreover, the DEM grid points of type I error are correct data and have to be reserved for fusion. The experiment result shows that using DEMs with terrain classification can obtain better blunder detection result. A proper setting of significant levels (α) can detect real blunders without creating too many type I errors. Weighting averaging is chosen as DEM fusion algorithm. The priori precisions estimated by our national DEM production guideline are applied to define weights. Fisher's test is implemented to prove that the priori precisions correspond to the RMSEs of blunder detection result.

  1. DEM interpolation based on artificial neural networks

    NASA Astrophysics Data System (ADS)

    Jiao, Limin; Liu, Yaolin

    2005-10-01

    This paper proposed a systemic resolution scheme of Digital Elevation model (DEM) interpolation based on Artificial Neural Networks (ANNs). In this paper, we employ BP network to fit terrain surface, and then detect and eliminate the samples with gross errors. This paper uses Self-organizing Feature Map (SOFM) to cluster elevation samples. The study area is divided into many more homogenous tiles after clustering. BP model is employed to interpolate DEM in each cluster. Because error samples are eliminated and clusters are built, interpolation result is better. The case study indicates that ANN interpolation scheme is feasible. It also shows that ANN can get a more accurate result by comparing ANN with polynomial and spline interpolation. ANN interpolation doesn't need to determine the interpolation function beforehand, so manmade influence is lessened. The ANN interpolation is more automatic and intelligent. At the end of the paper, we propose the idea of constructing ANN surface model. This model can be used in multi-scale DEM visualization, and DEM generalization, etc.

  2. Der Weltraum. Die Originalfotografien der NASA.

    NASA Astrophysics Data System (ADS)

    Klotz, H.

    This book is based on an exhibition in 1985 of many of the spectacular images obtainedby NASA's planetary missions and Earth reconnaissance satellites during the past two decades. The exhibition was organized by the Baxter Art Gallery, California Institute of Technology, Pasadena. The photographs have been prepared by the Jet Propulsion Laboratory, Pasadena.Contents: Das Sonnensystem - eine geowissenschaftliche Betrachtung (W. Ziegler). Der beharrliche Beobachter (C. Knight).Der Weltraum. Ranger - Der Mond. Surveyor - Der Mond. Lunar-Orbiter -Der Mond. Mariner 4, 6, 7 - Mars. Mariner 10 - Venus, Merkur. Viking - Mars. Voyager - Jupiter. Voyager - Saturn. Voyager - Uranus. Voyager - Neptun. Seasat. IRAS. SIR-A und SIR-B. Galileo. Beta Pictoris. Laufende Weltraumprojekte. Zukünftige Weltraumprojekte. Ein Blick zurück... und nach vorn (M. Maegraith). Anhang - Die Probleme der Bildübertragung. Chronologie der Weltraumflüge.

  3. „Überholen ohne einzuholen“ Die Entwicklung von Technologien für übermorgen in Kernenergie und Mikroelektronik der DDR

    NASA Astrophysics Data System (ADS)

    Barkleit, Gerhard

    Dem nuklearen Patt zwischen Ostblock und westlichem Staatenbündnis ist es nach weitgehend übereinstimmender Auffassung von Politik und Wissenschaft zu danken, dass der "Kalte Krieg" in der zweiten Hälfte des 20. Jahrhunderts nicht zum weltumfassenden Flächenbrand eskalierte. An der raschen Herstellung dieses Patts waren zwei Dresdner Physiker maßgeblich beteiligt, deren einer im Manhattan-Projekt in den USA gearbeitet hatte und später in England der Spionage für die Sowjetunion und des Verrats des Know-how der Atombombe überführt wurde.

  4. Kosmische Katastrophen und der Ursprung der Religion.

    NASA Astrophysics Data System (ADS)

    Hoyle, F.

    This book is a German translation, by V. Delavre, from the English original "The origin of the Universe and the origin of religion", published in 1993. Contents: E. Sens: Die unterbrochene Musikstunde. Einleitung zur deutschen Ausgabe. C. Ryskamp: Einführung. R. N. Anshen: Vorwort. F. Hoyle: Kosmische Katastrophen und der Ursprung der Religion - Die Folgen der Respektabilität; Eiszeiten und Kometen; Die allgemeine Situation in den Nacheiszeiten; Kometen und der Ursprung der Religionen; Der Übergang zu Mittelalter und Neuzeit. Diskussionsbeiträge: Ruth Nanda Anshen, Freeman Dyson, Paul Oscar Kristeller, John Archibald Wheeler, James Schwartz, Roger Shinn, Milton Gatch, Philip Solomon, Norman Newell. F. Hoyle: Schlußwort. A. Tollmann: Nachwort zur deutschen Ausgabe.

  5. Incorporating DEM Uncertainty in Coastal Inundation Mapping

    PubMed Central

    Leon, Javier X.; Heuvelink, Gerard B. M.; Phinn, Stuart R.

    2014-01-01

    Coastal managers require reliable spatial data on the extent and timing of potential coastal inundation, particularly in a changing climate. Most sea level rise (SLR) vulnerability assessments are undertaken using the easily implemented bathtub approach, where areas adjacent to the sea and below a given elevation are mapped using a deterministic line dividing potentially inundated from dry areas. This method only requires elevation data usually in the form of a digital elevation model (DEM). However, inherent errors in the DEM and spatial analysis of the bathtub model propagate into the inundation mapping. The aim of this study was to assess the impacts of spatially variable and spatially correlated elevation errors in high-spatial resolution DEMs for mapping coastal inundation. Elevation errors were best modelled using regression-kriging. This geostatistical model takes the spatial correlation in elevation errors into account, which has a significant impact on analyses that include spatial interactions, such as inundation modelling. The spatial variability of elevation errors was partially explained by land cover and terrain variables. Elevation errors were simulated using sequential Gaussian simulation, a Monte Carlo probabilistic approach. 1,000 error simulations were added to the original DEM and reclassified using a hydrologically correct bathtub method. The probability of inundation to a scenario combining a 1 in 100 year storm event over a 1 m SLR was calculated by counting the proportion of times from the 1,000 simulations that a location was inundated. This probabilistic approach can be used in a risk-aversive decision making process by planning for scenarios with different probabilities of occurrence. For example, results showed that when considering a 1% probability exceedance, the inundated area was approximately 11% larger than mapped using the deterministic bathtub approach. The probabilistic approach provides visually intuitive maps that convey

  6. Methodik der Erfassung und Bewertung von Biodiversitätsschäden aus ökologischer Sicht

    NASA Astrophysics Data System (ADS)

    Wiegleb, Gerhard; Krawczynski, René; Wagner, Hans-Georg

    Mit der Verabschiedung des Umweltschadensgesetzes (USchadG) hat der Schutz der Biodiversität in Deutschland ein neues Stadium erreicht. Zum ersten Male wird selbst die Vermeidung und Restitution der nichtintendierten Schädigung der Biodiversität in Gestalt bestimmter Arten und Lebensräume in ein umfassendes Naturschutzkonzept einbezogen. Das USchadG geht damit über die bisherigen Ansätze zum Schutz der belebten Natur hinaus, da es gleichzeitig neben der Erhaltung eines als günstig erkannten Ist-Zustandes der Biodiversität der Vermeidung vorhersehbarer Schäden sowie auch der Restitution nach einem eingetretenen Schaden verpflichtet ist. Naturschutzsystematisch gehört es wegen der Betonung der Vermeidung und Sanierung zum Bereich des reaktiven Naturschutzes (Gefahrenabwehr und Gefahrenbeseitigung), dem auch die Eingriffsregelung des Bundesnaturschutzgesetzes (BNatSchG), die Umweltverträglichkeitsprüfung nach Umweltverträglichkeitsprüfungsgesetz (UVPG) sowie die FFH-Verträglichkeitsprüfung nach Fauna-Flora-Habitat-Richtlinie (FFH-RL) zuzurechnen sind. Stärker noch als in den genannten Regelungen tritt im USchadG das Verursacherprinzip gegenüber der allgemeinen Umweltvorsorge in den Vordergrund.

  7. Spaceborne radar interferometry for coastal DEM construction

    USGS Publications Warehouse

    Hong, S.-H.; Lee, C.-W.; Won, J.-S.; Kwoun, Oh-Ig; Lu, Zhiming

    2005-01-01

    Topographic features in coastal regions including tidal flats change more significantly than landmass, and are characterized by extremely low slopes. High precision DEMs are required to monitor dynamic changes in coastal topography. It is difficult to obtain coherent interferometric SAR pairs especially over tidal flats mainly because of variation of tidal conditions. Here we focus on i) coherence of multi-pass ERS SAR interferometric pairs and ii) DEM construction from ERS-ENVISAT pairs. Coherences of multi-pass ERS interferograms were good enough to construct DEM under favorable tidal conditions. Coherence in sand dominant area was generally higher than that in muddy surface. The coarse grained coastal areas are favorable for multi-pass interferometry. Utilization of ERS-ENVISAT interferometric pairs is taken a growing interest. We carried out investigation using a cross-interferometric pair with a normal baseline of about 1.3 km, a 30 minutes temporal separation and the height sensitivity of about 6 meters. Preliminary results of ERS-ENVISAT interferometry were not successful due to baseline and unfavorable scattering conditions. ?? 2005 IEEE.

  8. Volcanic geomorphology using TanDEM-X

    NASA Astrophysics Data System (ADS)

    Poland, Michael; Kubanek, Julia

    2016-04-01

    Topography is perhaps the most fundamental dataset for any volcano, yet is surprisingly difficult to collect, especially during the course of an eruption. For example, photogrammetry and lidar are time-intensive and often expensive, and they cannot be employed when the surface is obscured by clouds. Ground-based surveys can operate in poor weather but have poor spatial resolution and may expose personnel to hazardous conditions. Repeat passes of synthetic aperture radar (SAR) data provide excellent spatial resolution, but topography in areas of surface change (from vegetation swaying in the wind to physical changes in the landscape) between radar passes cannot be imaged. The German Space Agency's TanDEM-X satellite system, however, solves this issue by simultaneously acquiring SAR data of the surface using a pair of orbiting satellites, thereby removing temporal change as a complicating factor in SAR-based topographic mapping. TanDEM-X measurements have demonstrated exceptional value in mapping the topography of volcanic environments in as-yet limited applications. The data provide excellent resolution (down to ~3-m pixel size) and are useful for updating topographic data at volcanoes where surface change has occurred since the most recent topographic dataset was collected. Such data can be used for applications ranging from correcting radar interferograms for topography, to modeling flow pathways in support of hazards mitigation. The most valuable contributions, however, relate to calculating volume changes related to eruptive activity. For example, limited datasets have provided critical measurements of lava dome growth and collapse at volcanoes including Merapi (Indonesia), Colima (Mexico), and Soufriere Hills (Montserrat), and of basaltic lava flow emplacement at Tolbachik (Kamchatka), Etna (Italy), and Kīlauea (Hawai`i). With topographic data spanning an eruption, it is possible to calculate eruption rates - information that might not otherwise be available

  9. Grundlagen der Mechatronik

    NASA Astrophysics Data System (ADS)

    Roddeck, Werner

    Der Begriff Mechatronik ist ein Kunstwort, welches durch Eindeutschung des englischen Wortes "Mechatronics“ entstanden ist. Dieses ist wiederum eine Zusammenziehung der englischen Bezeichnungen für "Mechanics“ (Maschinenbau) und "Electronics“ (Elektrotechnik). Der Begriff wurde durch einen japanischen Ingenieur 1969 geprägt und durch eine japanische Firma bis 1972 als Warenzeichen gehalten.

  10. Die Deutsche Statistische Gesellschaft in der Weimarer Republik und während der Nazidiktatur

    NASA Astrophysics Data System (ADS)

    Wilke, Jürgen

    Nach anfänglichen Schwierigkeiten durch den 1. Weltkrieg erlangte die Deutsche Statistische Gesellschaft (DStatG) unter dem renommierten Statistiker und Vorsitzenden der DStatG, Friedrich Zahn, durch eine Vielzahl von Aktivitäten hohes Ansehen. Es gab Bestrebungen, Statistiker aus allen Arbeitsfeldern der Statistik in die DStatG zu integrieren, wobei die "Mathematische Statistik" nur zögerlich akzeptiert wurde (Konjunkturforschung, Zeitreihenanalyse). Nach der Machtübernahme 1933 durch Adolf Hitler geriet die DStatG in das Fahrwasser nationalsozialistischer Ideologie und Politik (Führerprinzip, Gleichschaltung des Vereinswesens). Damit war eine personelle Umstrukturierung in der DStatG verbunden. Politisch Missliebige und rassisch Verfolgte mussten die DStatG verlassen (Bernstein, Freudenberg, Gumbel u.a.). Unter den Statistikern gab es alle Abstufungen im Verhalten zum Regime von Ablehnung und zwangsweiser Anpassung über bereitwilliges Mitläufertum bis zu bewusster Täterschaft. Besonders die Bevölkerungsstatistik wurde durch die NS- Rassenpolitik auf lange Sicht diskreditiert. Im Rahmen von Wirtschaftsplanung und Aufrüstung wurden neue zukunftsträchtige statistische Modelle (Grünig, Bramstedt, Leisse) entwickelt.

  11. Evaluation of DEM-assisted SAR coregistration

    NASA Astrophysics Data System (ADS)

    Nitti, D. O.; Hanssen, R. F.; Refice, A.; Bovenga, F.; Milillo, G.; Nutricato, R.

    2008-10-01

    Image alignment is without doubt the most crucial step in SAR Interferometry. Interferogram formation requires images to be coregistered with an accuracy of better than 1/8 pixel to avoid significant loss of phase coherence. Conventional interferometric precise coregistration methods for full-resolution SAR data (Single-Look Complex imagery, or SLC) are based on the cross-correlation of the SLC data, either in the original complex form or as squared amplitudes. Offset vectors in slant range and azimuth directions are computed on a large number of windows, according to the estimated correlation peaks. Then, a two-dimensional polynomial of a certain degree is usually chosen as warp function and the polynomial parameters are estimated through LMS fit from the shifts measured on the image windows. In case of rough topography and long baselines, the polynomial approximation for the warp function becomes inaccurate, leading to local misregistrations. Moreover, these effects increase with the spatial resolution and then with the sampling frequency of the sensor, as first results on TerraSAR-X interferometry confirm. An improved, DEM-assisted image coregistration procedure can be adopted for providing higher-order prediction of the offset vectors. Instead of estimating the shifts on a limited number of patches and using a polynomial approximation for the transformation, this approach computes pixel by pixel the correspondence between master and slave by using the orbital data and a reference DEM. This study assesses the performance of this approach with respect to the standard procedure. In particular, both analytical relationships and simulations will evaluate the impact of the finite vertical accuracy of the DEM on the final coregistration precision for different radar postings and relative positions of satellites. The two approaches are compared by processing real data at different carrier frequencies and using the interferometric coherence as quality figure.

  12. Kants Theorie der Sonne: Physikgeschichte

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2005-01-01

    Im Rahmen seiner Kosmogonie entwickelte der junge Immanuel Kant eine Theorie der Sonne. Sie ist ein einzigartiges Zeugnis seiner intuitiven Vorstellungskraft und beweist auch die Leistungsfähigkeit der damaligen, vorwiegend von Newton geprägten Weltsicht. Entstehung, Aufbau und Dynamik der Sonne werden in Kants Theorie ebenso erklärt wie etwa das Phänomen der Sonnenflecken.

  13. DEM time series of an agricultural watershed

    NASA Astrophysics Data System (ADS)

    Pineux, Nathalie; Lisein, Jonathan; Swerts, Gilles; Degré, Aurore

    2014-05-01

    In agricultural landscape soil surface evolves notably due to erosion and deposition phenomenon. Even if most of the field data come from plot scale studies, the watershed scale seems to be more appropriate to understand them. Currently, small unmanned aircraft systems and images treatments are improving. In this way, 3D models are built from multiple covering shots. When techniques for large areas would be to expensive for a watershed level study or techniques for small areas would be too time consumer, the unmanned aerial system seems to be a promising solution to quantify the erosion and deposition patterns. The increasing technical improvements in this growth field allow us to obtain a really good quality of data and a very high spatial resolution with a high Z accuracy. In the center of Belgium, we equipped an agricultural watershed of 124 ha. For three years (2011-2013), we have been monitoring weather (including rainfall erosivity using a spectropluviograph), discharge at three different locations, sediment in runoff water, and watershed microtopography through unmanned airborne imagery (Gatewing X100). We also collected all available historical data to try to capture the "long-term" changes in watershed morphology during the last decades: old topography maps, soil historical descriptions, etc. An erosion model (LANDSOIL) is also used to assess the evolution of the relief. Short-term evolution of the surface are now observed through flights done at 200m height. The pictures are taken with a side overlap equal to 80%. To precisely georeference the DEM produced, ground control points are placed on the study site and surveyed using a Leica GPS1200 (accuracy of 1cm for x and y coordinates and 1.5cm for the z coordinate). Flights are done each year in December to have an as bare as possible ground surface. Specific treatments are developed to counteract vegetation effect because it is know as key sources of error in the DEM produced by small unmanned aircraft

  14. Robust methods for assessing the accuracy of linear interpolated DEM

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Shi, Wenzhong; Liu, Eryong

    2015-02-01

    Methods for assessing the accuracy of a digital elevation model (DEM) with emphasis on robust methods have been studied in this paper. Based on the squared DEM residual population generated by the bi-linear interpolation method, three average-error statistics including (a) mean, (b) median, and (c) M-estimator are thoroughly investigated for measuring the interpolated DEM accuracy. Correspondingly, their confidence intervals are also constructed for each average error statistic to further evaluate the DEM quality. The first method mainly utilizes the student distribution while the second and third are derived from the robust theories. These innovative robust methods possess the capability of counteracting the outlier effects or even the skew distributed residuals in DEM accuracy assessment. Experimental studies using Monte Carlo simulation have commendably investigated the asymptotic convergence behavior of confidence intervals constructed by these three methods with the increase of sample size. It is demonstrated that the robust methods can produce more reliable DEM accuracy assessment results compared with those by the classical t-distribution-based method. Consequently, these proposed robust methods are strongly recommended for assessing DEM accuracy, particularly for those cases where the DEM residual population is evidently non-normal or heavily contaminated with outliers.

  15. Sitzungsberichte der Heidelberger Akademie der Wissenschaften> " Jahrgang 1990 Sitzungsber.Heidelberg 90 " "Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  16. Die Kosmologie der Griechen.

    NASA Astrophysics Data System (ADS)

    Mittelstraß, J.

    Contents: 1. Mythische Eier. 2. Thales-Welten. 3. "Alles ist voller Götter". 4. Griechische Astronomie. 5. "Rettung der Phänomene". 6. Aristotelische Kosmololgie. 7. Aristoteles-Welt und Platon-Welt. 8. Noch einmal: die Göttlichkeit der Welt. 9. Griechischer Idealismus.

  17. Aspects of dem Generation from Uas Imagery

    NASA Astrophysics Data System (ADS)

    Greiwe, A.; Gehrke, R.; Spreckels, V.; Schlienkamp, A.

    2013-08-01

    Since a few years, micro UAS (unmanned aerial systems) with vertical take off and landing capabilities like quadro- or octocopter are used as sensor platform for Aerophotogrammetry. Since the restricted payload of micro UAS with a total weight up of 5 kg (payload only up to 1.5 kg), these systems are often equipped with small format cameras. These cameras can be classified as amateur cameras and it is often the case, that these systems do not meet the requirements of a geometric stable camera for photogrammetric measurement purposes. However, once equipped with a suitable camera system, an UAS is an interesting alternative to expensive manned flights for small areas. The operating flight height of the above described UAS is about 50 up to 150 meters above ground level. This low flight height lead on the one hand to a very high spatial resolution of the aerial imagery. Depending on the cameras focal length and the sensor's pixel size, the ground sampling distance (GSD) is usually about 1 up to 5 cm. This high resolution is useful especially for the automatic generation of homologous tie-points, which are a precondition for the image alignment (bundle block adjustment). On the other hand, the image scale depends on the object's height and the UAV operating height. Objects like mine heaps or construction sites show high variations of the object's height. As a result, operating the UAS with a constant flying height will lead to high variations in the image scale. For some processing approaches this will lead to problems e.g. the automatic tie-point generation in stereo image pairs. As precondition to all DEM generating approaches, first of all a geometric stable camera, sharp images are essentially. Well known calibration parameters are necessary for the bundle adjustment, to control the exterior orientations. It can be shown, that a simultaneous on site camera calibration may lead to misaligned aerial images. Also, the success rate of an automatic tie-point generation

  18. Mit Mathematik zu Mehr Intelligenz in der Logistik

    NASA Astrophysics Data System (ADS)

    Möhring, Rolf H.; Schenk, Michael

    Die Lösung logistischer Probleme ist ein wichtiger Aspekt menschlichen Handelns seit Menschen gemeinsam zielgerichtet tätig wurden. Die Grundlagen dessen, was wir heute Logistik nennen, entstammen dem militärischen Bereich. So basierte z. B. das römische Imperium in starkem Maße auf militärisch-logistischen Glanzleistungen. Ob damals bereits mathematische Überlegungen eine Rolle spielten, wissen wir heute nicht. Jedoch versuchte z. B. Napoleon, der mit den bedeutendsten Mathematikern seiner Zeit befreundet war, den Transport seiner Truppen und die Verbreitung von Informationen zu optimieren und strategisch einzusetzen.1,2

  19. Evaluation of on-line DEMs for flood inundation modeling

    NASA Astrophysics Data System (ADS)

    Sanders, Brett F.

    2007-08-01

    Recent and highly accurate topographic data should be used for flood inundation modeling, but this is not always feasible given time and budget constraints so the utility of several on-line digital elevation models (DEMs) is examined with a set of steady and unsteady test problems. DEMs are used to parameterize a 2D hydrodynamic flood simulation algorithm and predictions are compared with published flood maps and observed flood conditions. DEMs based on airborne light detection and ranging (LiDAR) are preferred because of horizontal resolution, vertical accuracy (˜0.1 m) and the ability to separate bare-earth from built structures and vegetation. DEMs based on airborne interferometric synthetic aperture radar (IfSAR) have good horizontal resolution but gridded elevations reflect built structures and vegetation and therefore further processing may be required to permit flood modeling. IfSAR and shuttle radar topography mission (SRTM) DEMs suffer from radar speckle, or noise, so flood plains may appear with non-physical relief and predicted flood zones may include non-physical pools. DEMs based on national elevation data (NED) are remarkably smooth in comparison to IfSAR and SRTM but using NED, flood predictions overestimate flood extent in comparison to all other DEMs including LiDAR, the most accurate. This study highlights utility in SRTM as a global source of terrain data for flood modeling.

  20. Herausforderungen und Best Practices bei der Speicherung von multi-valued Attributen in LDAP-basierten Verzeichnisdiensten

    NASA Astrophysics Data System (ADS)

    Hommel, Wolfgang; Pluta, Daniel

    LDAP-basierte Verzeichnisdienste unterscheiden sich von relationalen Datenbankmanagementsystemen unter anderem stark bezüglich der Datenmodellierung. Dieser Artikel vertieft eingangs die Herausforderungen bei der LDAP-spezifischen Abbildung von Relationen zwischen mehreren multivalued Attributen. Die Diskussion erfolgt vor dem Hintergrund, dass einerseits Verzeichnisdienste generell nur bedingt zur Speicherung von Relationen geeignet sind und dass andererseits multi-valued Attribute ein mächtiges LDAP-Instrument sind, zu dem es in relationalen Datenbanksystemen keine direkte Entsprechung gibt. Anschließend werden Lösungskonzepte vorgestellt und mögliche Weiterentwicklungen des IntegraTUM-LDAP-Schemas zu deren Umsetzung skizziert, eine exemplarische Implementierung präsentiert und die Ergebnisse der bisherigen Entwicklung des IntegraTUM-Schemas gegenübergestellt.

  1. Cyber-Physical Systems - Wissenschaftliche Herausforderungen Bei Der Entwicklung

    NASA Astrophysics Data System (ADS)

    Broy, Manfred

    Cyber-Physical Systems adressieren die enge Verbindung eingebetteter Systeme zur Überwachung und Steuerung physikalischer Vorgänge mittels Sensoren und Aktuatoren über Kommunikationseinrichtungen mit den globalen digitalen Netzen (dem Cyberspace"). Dieser Typus von Systemen ermöglicht über Wirkketten eine Verbindung zwischen Vorgängen der physischen Realität und den heute verfügbaren digitalen Netzinfrastrukturen. Dies erlaubt vielfältige Applikationen mit hohem wirtschaftlichen Potential, und mit starker Innovationskraft. Die vollständige Ausschöpfung des Potentials erfordert aber gezielte wissenschaftliche Anstrengungen bei der Entwicklung solcher Systeme im Hinblick auf Methodik, Technologie, Kostenbeherrschung und funktionale Angemessenheit.

  2. Die Amtliche Sammlung von Untersuchungsverfahren nach § 64 LFGB, § 35 Vorläufiges Tabakgesetz und § 28b Gentechnikgesetz - ein Instrument der amtlichen Lebensmittelüberwachung

    NASA Astrophysics Data System (ADS)

    Renger, Silke; Stachel, Carolin

    Immer wieder werden Skandale in Zusammenhang mit Lebensmitteln bekannt. Schlagworte wie BSE, Gammelfleisch, Acrylamid, Cumarin oder auch Melamin, Dioxin sind den Verbrauchern geläufig und erschüttern das Vertrauen in ein gesundes und ernährungsphysiologisch wertvolles Lebensmittel. Das Bewusstsein des Verbrauchers hinsichtlich der Ernährung und der Auswahl beim Kauf der Lebensmittel hat sich in den vergangenen Jahren deutlich verändert. Bei der Auswahl seiner Lebensmittel liegt sein Augenmerk verstärkt auf gesunden, qualitativ hochwertigen und vor allem sicheren Lebensmitteln. Dies wurde insbesondere bei dem verhaltenen Kauf von Fleisch und Fleischerzeugnissen während der BSE-Krise oder auch dem kürzlich aufgetretenen Gammelfleischskandal deutlich.

  3. EMDataBank unified data resource for 3DEM

    PubMed Central

    Lawson, Catherine L.; Patwardhan, Ardan; Baker, Matthew L.; Hryc, Corey; Garcia, Eduardo Sanz; Hudson, Brian P.; Lagerstedt, Ingvar; Ludtke, Steven J.; Pintilie, Grigore; Sala, Raul; Westbrook, John D.; Berman, Helen M.; Kleywegt, Gerard J.; Chiu, Wah

    2016-01-01

    Three-dimensional Electron Microscopy (3DEM) has become a key experimental method in structural biology for a broad spectrum of biological specimens from molecules to cells. The EMDataBank project provides a unified portal for deposition, retrieval and analysis of 3DEM density maps, atomic models and associated metadata (emdatabank.org). We provide here an overview of the rapidly growing 3DEM structural data archives, which include maps in EM Data Bank and map-derived models in the Protein Data Bank. In addition, we describe progress and approaches toward development of validation protocols and methods, working with the scientific community, in order to create a validation pipeline for 3DEM data. PMID:26578576

  4. DEM simulation of granular flow in a Couette device

    NASA Astrophysics Data System (ADS)

    Vidyapati, Vidyapati; Kheripour Langrudi, M.; Tardos, Gabriel; Sun, Jin; Sundaresan, Sankaran; Subramaniam, Shankar

    2009-11-01

    We study the shear motion of granular material in an annular shear cell operated in batch and continuous modes. In order to quantitatively simulate shear behavior of granular material composed of spherical shaped grains, a 3D discrete element method (DEM) is used. The ultimate goal of the present work is to compare DEM results for the normal and shear stresses in stationary and moving granular beds confined in Couette device with experimental results. The DEM captures the experimental observation of transition behavior from quasi-- static (in batch mode operation) to rapid flow (in continuous mode operation) regime of granular flows. Although there are quantitative differences between DEM model predictions and experiments, the qualitative features are nicely reproduced. It is observed (both in experiments and in simulations) that the intermediate regime is broad enough to require a critical assessment of continuum models for granular flows.

  5. High-resolution DEM Effects on Geophysical Flow Models

    NASA Astrophysics Data System (ADS)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (<10-15°) slope angles are involved. At these slope angles, multiple adjacent DEM cell elevation values are equal due to the need for the DEM to approximate the low slope with a limited set of integer values for elevation. The first derivative of the elevation surface thus becomes zero. In these cases, flow propagation is inhibited by these spurious zero-slope conditions. Here we present evidence for this "terracing effect" from 1) a mathematically defined simulated elevation model, to demonstrate the terracing effects of integer valued data, and 2) a real-world DEM where terracing must be

  6. The TanDEM-X Digital Elevation Model and the Terrestrial Impact Crater Record

    NASA Astrophysics Data System (ADS)

    Gottwald, M.; Fritz, T.; Breit, H.; Schättler, B.; Harris, A.

    2016-08-01

    The German TanDEM-X mission provides a new high-quality DEM of the Earth's surface. We present the current status of this DEM, show how it compares with existing DEMs from spaceborne sensors and illustrate results of our global mapping project.

  7. Shading-based DEM refinement under a comprehensive imaging model

    NASA Astrophysics Data System (ADS)

    Peng, Jianwei; Zhang, Yi; Shan, Jie

    2015-12-01

    This paper introduces an approach to refine coarse digital elevation models (DEMs) based on the shape-from-shading (SfS) technique using a single image. Different from previous studies, this approach is designed for heterogeneous terrain and derived from a comprehensive (extended) imaging model accounting for the combined effect of atmosphere, reflectance, and shading. To solve this intrinsic ill-posed problem, the least squares method and a subsequent optimization procedure are applied in this approach to estimate the shading component, from which the terrain gradient is recovered with a modified optimization method. Integrating the resultant gradients then yields a refined DEM at the same resolution as the input image. The proposed SfS method is evaluated using 30 m Landsat-8 OLI multispectral images and 30 m SRTM DEMs. As demonstrated in this paper, the proposed approach is able to reproduce terrain structures with a higher fidelity; and at medium to large up-scale ratios, can achieve elevation accuracy 20-30% better than the conventional interpolation methods. Further, this property is shown to be stable and independent of topographic complexity. With the ever-increasing public availability of satellite images and DEMs, the developed technique is meaningful for global or local DEM product refinement.

  8. Generating DEM from LIDAR data - comparison of available software tools

    NASA Astrophysics Data System (ADS)

    Korzeniowska, K.; Lacka, M.

    2011-12-01

    In recent years many software tools and applications have appeared that offer procedures, scripts and algorithms to process and visualize ALS data. This variety of software tools and of "point cloud" processing methods contributed to the aim of this study: to assess algorithms available in various software tools that are used to classify LIDAR "point cloud" data, through a careful examination of Digital Elevation Models (DEMs) generated from LIDAR data on a base of these algorithms. The works focused on the most important available software tools: both commercial and open source ones. Two sites in a mountain area were selected for the study. The area of each site is 0.645 sq km. DEMs generated with analysed software tools ware compared with a reference dataset, generated using manual methods to eliminate non ground points. Surfaces were analysed using raster analysis. Minimum, maximum and mean differences between reference DEM and DEMs generated with analysed software tools were calculated, together with Root Mean Square Error. Differences between DEMs were also examined visually using transects along the grid axes in the test sites.

  9. Arzt und Hobby-Astronom in stürmischen Zeiten Der Büchernachlass des Doktor Johannes Häringshauser, Viertelsmedicus in Mistelbach (1630-1641) in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Davison, Giles; Glaßner, Gottfried

    2009-06-01

    Auf der Suche nach astronomischer Literatur stieß Giles Davison in der Melker Stiftsbibliothek auf den Namen "Doctor Johannes Häringshauser“ als Besitzer seltener und interessanter astronomischer Werke u.a. von Johannes Regiomontan, Georg von Peuerbach, Michael Mästlin, Johannes Kepler und Daniel Sennert. Weitere in den Jahren 2007-2009 durchgeführte Nachforschungen ergaben, dass es sich um den von 1630-1641 in Mistelbach, Niederösterreich, als Landschaftsarzt tätigen Vater des Melker Konventualen und Bibliothekars Sigismund Häringshauser (1631-1698) handelt. Er wurde 1603 als Sohn des aus Magdeburg stammenden Apothekers Johannes Häringshauser geboren und starb 1642 in Mistelbach. Johannes Häringshauser Sen. bekleidete von 1613-1640 eine Reihe wichtiger Ämter in der Wiener Stadtregierung und starb 1647. Der Studienaufenthalt von Dr. Johannes Häringshauser Jun. in Padua (1624-1626) dürfte das Interesse für Astronomie geweckt haben, das sich in seiner in die Bestände der Melker Stiftsbibliothek eingegangenen Privatbibliothek widerspiegelt. Der Großteil der 10 dem Fachbereich der Astronomie und Astrologie zuzuweisenden Titel wurde von ihm in den Jahren 1636 und 1637 erworben.

  10. Evaluating the Accuracy of dem Generation Algorithms from Uav Imagery

    NASA Astrophysics Data System (ADS)

    Ruiz, J. J.; Diaz-Mas, L.; Perez, F.; Viguria, A.

    2013-08-01

    In this work we evaluated how the use of different positioning systems affects the accuracy of Digital Elevation Models (DEMs) generated from aerial imagery obtained with Unmanned Aerial Vehicles (UAVs). In this domain, state-of-the-art DEM generation algorithms suffer from typical errors obtained by GPS/INS devices in the position measurements associated with each picture obtained. The deviations from these measurements to real world positions are about meters. The experiments have been carried out using a small quadrotor in the indoor testbed at the Center for Advanced Aerospace Technologies (CATEC). This testbed houses a system that is able to track small markers mounted on the UAV and along the scenario with millimeter precision. This provides very precise position measurements, to which we can add random noise to simulate errors in different GPS receivers. The results showed that final DEM accuracy clearly depends on the positioning information.

  11. The effects of wavelet compression on Digital Elevation Models (DEMs)

    USGS Publications Warehouse

    Oimoen, M.J.

    2004-01-01

    This paper investigates the effects of lossy compression on floating-point digital elevation models using the discrete wavelet transform. The compression of elevation data poses a different set of problems and concerns than does the compression of images. Most notably, the usefulness of DEMs depends largely in the quality of their derivatives, such as slope and aspect. Three areas extracted from the U.S. Geological Survey's National Elevation Dataset were transformed to the wavelet domain using the third order filters of the Daubechies family (DAUB6), and were made sparse by setting 95 percent of the smallest wavelet coefficients to zero. The resulting raster is compressible to a corresponding degree. The effects of the nulled coefficients on the reconstructed DEM are noted as residuals in elevation, derived slope and aspect, and delineation of drainage basins and streamlines. A simple masking technique also is presented, that maintains the integrity and flatness of water bodies in the reconstructed DEM.

  12. Extract relevant features from DEM for groundwater potential mapping

    NASA Astrophysics Data System (ADS)

    Liu, T.; Yan, H.; Zhai, L.

    2015-06-01

    Multi-criteria evaluation (MCE) method has been applied much in groundwater potential mapping researches. But when to data scarce areas, it will encounter lots of problems due to limited data. Digital Elevation Model (DEM) is the digital representations of the topography, and has many applications in various fields. Former researches had been approved that much information concerned to groundwater potential mapping (such as geological features, terrain features, hydrology features, etc.) can be extracted from DEM data. This made using DEM data for groundwater potential mapping is feasible. In this research, one of the most widely used and also easy to access data in GIS, DEM data was used to extract information for groundwater potential mapping in batter river basin in Alberta, Canada. First five determining factors for potential ground water mapping were put forward based on previous studies (lineaments and lineament density, drainage networks and its density, topographic wetness index (TWI), relief and convergence Index (CI)). Extraction methods of the five determining factors from DEM were put forward and thematic maps were produced accordingly. Cumulative effects matrix was used for weight assignment, a multi-criteria evaluation process was carried out by ArcGIS software to delineate the potential groundwater map. The final groundwater potential map was divided into five categories, viz., non-potential, poor, moderate, good, and excellent zones. Eventually, the success rate curve was drawn and the area under curve (AUC) was figured out for validation. Validation result showed that the success rate of the model was 79% and approved the method's feasibility. The method afforded a new way for researches on groundwater management in areas suffers from data scarcity, and also broaden the application area of DEM data.

  13. Der vollständige Brief Brahes an Sørensen über das Erscheinen des Kometen von 1577

    NASA Astrophysics Data System (ADS)

    Kirschner, Stefan

    Es ist erstaunlich, daß sowohl Friis als auch Dreyer in ihrer Ausgabe der Briefe Tycho Brahes den Brief vom 14. November 1577 an Peter Sørensen, die erste bekannte Nachricht Brahes von seiner Entdeckung des Kometen von 1577, nur unvollständig, und zwar ohne den astronomischen Inhalt, ediert haben. Der Brief, dessen Original sehr wahrscheinlich nicht mehr existiert, wurde von dem Kieler Arzt und Medizinprofessor Johann Daniel Major (1634 - 1693) in Kopenhagen in sein Reisetagebuch kopiert. Das Original des Majorschen Reisetagebuches ist verschollen, doch es existieren zwei Abschriften davon (Kopenhagen, Königl. Bibl., Ny Kgl. Sml., 365, Fol. u. Ledreborg, 410, Fol.). Im folgenden wird nach einer kurzen Beschreibung des Stellenwerts, den der Komet von 1577 für Brahe besaß, der Brief nach diesen beiden Abschriften kritisch ediert, mit einer deutschen Übersetzung versehen und kurz kommentiert.

  14. Zum Stellenwert der Unterdruck-Instillationstherapie in der Dermatologie.

    PubMed

    Müller, Cornelia Sigrid Lissi; Burgard, Barbara; Zimmerman, Monika; Vogt, Thomas; Pföhler, Claudia

    2016-08-01

    Die Methoden zur Behandlung akuter und chronischer Wunden unterliegen einer steten Weiterentwicklung, Reevaluierung und Anwendung innovativer Therapieformen. Die Vakuumtherapie zur Wundbehandlung gehört zu den etablierten Behandlungsmodalitäten. Ein innovatives Verfahren kombiniert die Vakuumtherapie mit der automatisierten, kontrollierten Zufuhr und Drainage wirkstoffhaltiger Lösungen zur topischen Wundbehandlung im Wundbett und auch wirkstofffrei durch Instillation physiologischer Kochsalzlösung (Unterdruck-Instillationstherapie). Hierdurch können die Effekte der konventionellen Vakuumtherapie mit denen der lokalen Antisepsis kombiniert werden. Hierdurch kommt es zu einer Reduktion der Wundfläche, einer Induktion von Granulationsgewebe sowie einer Reduktion der Keimbesiedelung der Wunden. Bisher publizierte Studien konzentrieren sich auf die Anwendung dieses Therapieverfahrens zur Behandlung orthopädisch-chirurgischer Krankheiten. Die Datenlage bezüglich der Vakuum-Instillationstherapie in der Dermatochirurgie beschränkt sich derzeit auf Fallberichte und Einzelfallerfahrungen. Randomisierte, prospektive Studien zum Vergleich der Vakuum-Instillationstherapie zur Behandlung dermatologischer Krankheitsbilder existieren bislang nicht. Ziele des vorliegenden Artikels sind die Vorstellung der Vakuumtherapie mit Instillation einschließlich ihres Wirkprinzips, deren mögliche Komplikationen, die Diskussion erdenklicher Kontraindikationen sowie eine Übersicht über die aktuell verfügbare Datenlage. Zusammenfassend scheint sich die Evidenz zu verdichten, dass mittels Unterdruck-Instillationstherapie sowohl einfache als auch komplizierte Wunden effizient behandelt werden können, was sich in einer deutlichen Beschleunigung der Wundgranulation mit konsekutiv früher möglichem Defektverschluss äußert. PMID:27509413

  15. Precise baseline determination for the TanDEM-X mission

    NASA Astrophysics Data System (ADS)

    Koenig, Rolf; Moon, Yongjin; Neumayer, Hans; Wermuth, Martin; Montenbruck, Oliver; Jäggi, Adrian

    The TanDEM-X mission will strive for generating a global precise Digital Elevation Model (DEM) by way of bi-static SAR in a close formation of the TerraSAR-X satellite, already launched on June 15, 2007, and the TanDEM-X satellite to be launched in May 2010. Both satellites carry the Tracking, Occultation and Ranging (TOR) payload supplied by the GFZ German Research Centre for Geosciences. The TOR consists of a high-precision dual-frequency GPS receiver, called Integrated GPS Occultation Receiver (IGOR), and a Laser retro-reflector (LRR) for precise orbit determination (POD) and atmospheric sounding. The IGOR is of vital importance for the TanDEM-X mission objectives as the millimeter level determination of the baseline or distance between the two spacecrafts is needed to derive meter level accurate DEMs. Within the TanDEM-X ground segment GFZ is responsible for the operational provision of precise baselines. For this GFZ uses two software chains, first its Earth Parameter and Orbit System (EPOS) software and second the BERNESE software, for backup purposes and quality control. In a concerted effort also the German Aerospace Center (DLR) generates precise baselines independently with a dedicated Kalman filter approach realized in its FRNS software. By the example of GRACE the generation of baselines with millimeter accuracy from on-board GPS data can be validated directly by way of comparing them to the intersatellite K-band range measurements. The K-band ranges are accurate down to the micrometer-level and therefore may be considered as truth. Both TanDEM-X baseline providers are able to generate GRACE baselines with sub-millimeter accuracy. By merging the independent baselines by GFZ and DLR, the accuracy can even be increased. The K-band validation however covers solely the along-track component as the K-band data measure just the distance between the two GRACE satellites. In addition they inhibit an un-known bias which must be modelled in the comparison, so the

  16. Sitzungsberichte der Heidelberger Akademie der Wissenschaften¬Jahrgang 1990 Sitzungsber.Heidelberg 90¬"Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  17. Van der Waals Forces

    NASA Astrophysics Data System (ADS)

    Parsegian, V. Adrian

    2006-03-01

    This should prove to be the definitive work explaining van der Waals forces, how to calculate them and take account of their impact under any circumstances and conditions. These weak intermolecular forces are of truly pervasive impact, and biologists, chemists, physicists and engineers will profit greatly from the thorough grounding in these fundamental forces that this book offers. Parsegian has organized his book at three successive levels of mathematical sophistication, to satisfy the needs and interests of readers at all levels of preparation. The Prelude and Level 1 are intended to give everyone an overview in words and pictures of the modern theory of van der Waals forces. Level 2 gives the formulae and a wide range of algorithms to let readers compute the van der Waals forces under virtually any physical or physiological conditions. Level 3 offers a rigorous basic formulation of the theory. Author is among the most highly respected biophysicists Van der Waals forces are significant for a wide range of questions and problems in the life sciences, chemistry, physics, and engineering, ranging up to the macro level No other book that develops the subject vigorously, and this book also makes the subject intuitively accessible to students who had not previously been mathematically sophisticated enough to calculate them

  18. Spatial Characterization of Landscapes through Multifractal Analysis of DEM

    PubMed Central

    Aguado, P. L.; Del Monte, J. P.; Moratiel, R.; Tarquis, A. M.

    2014-01-01

    Landscape evolution is driven by abiotic, biotic, and anthropic factors. The interactions among these factors and their influence at different scales create a complex dynamic. Landscapes have been shown to exhibit numerous scaling laws, from Horton's laws to more sophisticated scaling of heights in topography and river network topology. This scaling and multiscaling analysis has the potential to characterise the landscape in terms of the statistical signature of the measure selected. The study zone is a matrix obtained from a digital elevation model (DEM) (map 10 × 10 m, and height 1 m) that corresponds to homogeneous region with respect to soil characteristics and climatology known as “Monte El Pardo” although the water level of a reservoir and the topography play a main role on its organization and evolution. We have investigated whether the multifractal analysis of a DEM shows common features that can be used to reveal the underlying patterns and information associated with the landscape of the DEM mapping and studied the influence of the water level of the reservoir on the applied analysis. The results show that the use of the multifractal approach with mean absolute gradient data is a useful tool for analysing the topography represented by the DEM. PMID:25177728

  19. SAR interferometry for DEM generation: wide-area error assessment

    NASA Astrophysics Data System (ADS)

    Carrasco, Daniel; Broquetas, Antoni; Pena, Ramon; Arbiol, Roman; Castillo, Manuel; Pala, Vincenc

    1998-11-01

    The present work consists on the generation of a DEM using ERS satellites interferometric data over a wide area (50 X 50 Km) with an error study using a high accuracy reference DEM, focusing on the atmosphere induced errors. The area is heterogeneous with flat and rough topography ranging from sea level up to 1200 m in the inland ranges. The ERS image has a 100 X 100 Km2 area and has been divided in four quarters to ease the processing. The phase unwrapping algorithm, which is a combination of region growing and least squares techniques, worked out successfully the rough topography areas. One quarter of the full scene was geocoded over a local datum ellipsoid to a UTM grid. The resulting DEM was compared to a reference one provided by the Institut Cartografic de Catalunya. Two types of atmospheric error or artifacts were found: a set of very localized spots, up to one phase cycle, which generated ghost hills up to 100, and a slow trend effect which added up to 50 m to some areas in the image. Besides of the atmospheric errors, the quality of the DEM was assessed. The quantitative error study was carried out locally at several areas with different topography.

  20. DEMS - a second generation diabetes electronic management system.

    PubMed

    Gorman, C A; Zimmerman, B R; Smith, S A; Dinneen, S F; Knudsen, J B; Holm, D; Jorgensen, B; Bjornsen, S; Planet, K; Hanson, P; Rizza, R A

    2000-06-01

    Diabetes electronic management system (DEMS) is a component-based client/server application, written in Visual C++ and Visual Basic, with the database server running Sybase System 11. DEMS is built entirely with a combination of dynamic link libraries (DLLs) and ActiveX components - the only exception is the DEMS.exe. DEMS is a chronic disease management system for patients with diabetes. It is used at the point of care by all members of the diabetes team including physicians, nurses, dieticians, clinical assistants and educators. The system is designed for maximum clinical efficiency and facilitates appropriately supervised delegation of care. Dispersed clinical sites may be supervised from a central location. The system is designed for ease of navigation; immediate provision of many types of automatically generated reports; quality audits; aids to compliance with good care guidelines; and alerts, advisories, prompts, and warnings that guide the care provider. The system now contains data on over 34000 patients and is in daily use at multiple sites.

  1. Qualität auf dem Prüfstand

    NASA Astrophysics Data System (ADS)

    Michaelis, Michael

    An einem Wochenende im Dezember 2009 beendete der chinesische Eisenbahn-Vizeminister Hu Yadong in Begleitung einer hochrangigen Delegation aus Experten des Department of Safety seines Ministeriums eine mehrtägige Europareise mit einem Besuch in der Konzernzentrale des weltweit führenden Herstellers von Bremssystemen für Schienen- und Nutzfahrzeuge in München. Schon in wenigen Jahren wird China über die weltweit größte Flotte an Hochgeschwindigkeitszügen verfügen und dabei sind Sicherheit und Qualität vorrangige Anforderungen. Knorr-Bremse liefert 100% der Bremsanlagen dieser Züge und hat vor kurzem mit rund 500 Millionen Euro den größten Auftrag in der Firmengeschichte erhalten. Das Unternehmen wird zusammen mit seinen chinesischen Partnern insgesamt 2.720 neue Wagen des chinesischen Hochgeschwindigkeitszuges CRH3 mit Brems- und Türsystemen ausrüsten.

  2. Evaluation der zentralen TUM-Lernplattform

    NASA Astrophysics Data System (ADS)

    Schulze, Elvira; Baume, Matthias; Graf, Stephan; Gergintchev, Ivan

    Die Notwendigkeit der Qualitätssicherung und -kontrolle für innovative universitäre Lehr-/Lernszenarien ist in der Praxis unbestritten. Die Wirksamkeit der Einführung der zentralen Lernplattform CLIX Campus der imc AG an der TUM wurde mittels quantitativer und qualitativer Evaluation überprüft. Als statistische Bewertungsgrundlage wurde der Erreichungsgrad bestimmter Projektziele herangezogen. Aufbauend auf den theoretischen Grundlagen der Evaluation von Bildungsangeboten gibt diese Studie Aufschluss über die Ergebnisse der Datenerhebungen sowie die Einschätzung der Plattform aus Nutzersicht und belegt die wesentliche Bedeutung der durchgängigen IT-Infrastruktur und speziell der einheitlichen Verfügbarkeit der eLearning Angebote.

  3. Entwicklung und methodische Verbesserung der Arbeitssicherheit in der Instandhaltung

    NASA Astrophysics Data System (ADS)

    Galinski, Marek

    Die Hüttenwerke Krupp Mannesmann gehören zu den führenden Stahlherstellern in Europa. Die Instandhaltung ist einerseits den Anlagen vor Ort zugeordnet, andererseits gibt es für werksweite bzw. spezielle Themen eine zentrale Instandhaltung. Die im Folgenden beschriebenen Methoden wurden für das gesamte Unternehmen entwickelt, jedoch je nach Organisationseinheit unterschiedlich adaptiert und unterschiedlich intensiv verfolgt. Die zentrale Instandhaltung hat insbesondere in den letzten 12 Jahren der Arbeitssicherheit einen hohen Stellenwert beigemessen, und hervorragende Ergebnisse erzielt. So ist die Unfallhäufigkeit in der zentralen Instandhaltung von ca. 30 anzeigepflichtigen Unfällen pro eine Million verfahrener Stunden vor ca. 15 Jahren auf Null in 2007 gesunken! In 2008 konnte dieses hervorragende Ergebnis gehalten werden. Zwei Jahre unfallfrei! Wer hätte das vor 15 Jahren gedacht? Der Schwerpunkt des Beitrags liegt auf der Erläuterung der Ansatzpunkte mit denen dieses Ergebnis erreicht wurde und der Darstellung der Methoden incl. der Anpassung an die veränderten Ansatzpunkte in den betroffenen Bereichen. Die beschriebenen Methoden sind in der zentralen Instandhaltung so angewendet worden.

  4. Neue Entwicklungen in der Berufsdermatologie.

    PubMed

    Diepgen, Thomas L

    2016-09-01

    Berufsbedingte Hautkrankheiten nach BK-Nr. 5101 stehen in Deutschland seit vielen Jahren an der Spitze der angezeigten Berufskrankheiten. Durch die Optimierung von Maßnahmen der primären, sekundären und tertiären Prävention können heutzutage die meisten Betroffenen im Beruf verbleiben. Zum 01.01.2015 wurde die Berufskrankheitenverordnung (BKV) novelliert und es wurde die BK-Nr. 5103 "Plattenepithelkarzinome oder multiple aktinische Keratosen der Haut durch natürliche UV-Strahlung" als neue Berufskrankheit in die BK-Liste der BKV aufgenommen. Die Definition von "multipel" bedeutet dabei entweder mehr als fünf einzelne aktinische Keratosen innerhalb eines Zeitraums von 12 Monaten oder das Vorliegen einer Feldkanzerisierung von größer 4 cm(2) . Wichtige Aspekte dieser neuen Berufskrankheit werden aufgezeigt und diskutiert sowie Neuerungen bei der BK 5101 angesprochen. PMID:27607028

  5. Development of parallel DEM for the open source code MFIX

    SciTech Connect

    Gopalakrishnan, Pradeep; Tafti, Danesh

    2013-02-01

    The paper presents the development of a parallel Discrete Element Method (DEM) solver for the open source code, Multiphase Flow with Interphase eXchange (MFIX) based on the domain decomposition method. The performance of the code was evaluated by simulating a bubbling fluidized bed with 2.5 million particles. The DEM solver shows strong scalability up to 256 processors with an efficiency of 81%. Further, to analyze weak scaling, the static height of the fluidized bed was increased to hold 5 and 10 million particles. The results show that global communication cost increases with problem size while the computational cost remains constant. Further, the effects of static bed height on the bubble hydrodynamics and mixing characteristics are analyzed.

  6. DEM interpolation weight calculation modulus based on maximum entropy

    NASA Astrophysics Data System (ADS)

    Chen, Tian-wei; Yang, Xia

    2015-12-01

    There is negative-weight in traditional interpolation of gridding DEM, in the article, the principle of Maximum Entropy is utilized to analyze the model system which depends on modulus of space weight. Negative-weight problem of the DEM interpolation is researched via building Maximum Entropy model, and adding nonnegative, first and second order's Moment constraints, the negative-weight problem is solved. The correctness and accuracy of the method was validated with genetic algorithm in matlab program. The method is compared with the method of Yang Chizhong interpolation and quadratic program. Comparison shows that the volume and scaling of Maximum Entropy's weight is fit to relations of space and the accuracy is superior to the latter two.

  7. A description of rotations for DEM models of particle systems

    NASA Astrophysics Data System (ADS)

    Campello, Eduardo M. B.

    2015-06-01

    In this work, we show how a vector parameterization of rotations can be adopted to describe the rotational motion of particles within the framework of the discrete element method (DEM). It is based on the use of a special rotation vector, called Rodrigues rotation vector, and accounts for finite rotations in a fully exact manner. The use of fictitious entities such as quaternions or complicated structures such as Euler angles is thereby circumvented. As an additional advantage, stick-slip friction models with inter-particle rolling motion are made possible in a consistent and elegant way. A few examples are provided to illustrate the applicability of the scheme. We believe that simple vector descriptions of rotations are very useful for DEM models of particle systems.

  8. Effect of DEM mesh size on AnnAGNPS simulation and slope correction.

    PubMed

    Wang, Xiaoyan; Lin, Q

    2011-08-01

    The objective of this paper is to study the impact of the mesh size of the digital elevation model (DEM) on terrain attributes within an Annualized AGricultural NonPoint Source pollution (AnnAGNPS) Model simulation at watershed scale and provide a correction of slope gradient for low resolution DEMs. The effect of different grid sizes of DEMs on terrain attributes was examined by comparing eight DEMs (30, 40, 50, 60, 70, 80, 90, and 100 m). The accuracy of the AnnAGNPS stimulation on runoff, sediments, and nutrient loads is evaluated. The results are as follows: (1) Rnoff does not vary much with decrease of DEM resolution whereas soil erosion and total nitrogen (TN) load change prominently. There is little effect on runoff simulation of AnnAGNPS modeling by the amended slope using an adjusted 50 m DEM. (2) A decrease of sediment yield and TN load is observed with an increase of DEM mesh size from 30 to 60 m; a slight decrease of sediment and TN load with the DEM mesh size bigger than 60 m. There is similar trend for total phosphorus (TP) variation, but with less range of variation, the simulation of sediment, TN, and TP increase, in which sediment increase up to 1.75 times compared to the model using unadjusted 50 m DEM. In all, the amended simulation still has a large difference relative to the results using 30 m DEM. AnnAGNPS is less reliable for sediment loading prediction in a small hilly watershed. (3) Resolution of DEM has significant impact on slope gradient. The average, minimum, maximum of slope from the various DEMs reduced obviously with the decrease of DEM precision. For the grade of 0∼15°, the slopes at lower resolution DEM are generally bigger than those at higher resolution DEM. But for the grade bigger than 15°, the slopes at lower resolution DEM are generally smaller than those at higher resolution DEM. So it is necessary to adjust the slope with a fitting equation. A cubic model is used for correction of slope gradient from lower resolution to

  9. Separability of soils in a tallgrass prairie using SPOT and DEM data

    NASA Technical Reports Server (NTRS)

    Su, Haiping; Ransom, Michel D.; Yang, Shie-Shien; Kanemasu, Edward T.

    1990-01-01

    An investigation is conducted which uses a canonical transformation technique to reduce the features from SPOT and DEM data and evaluates the statistical separability of several prairie soils from the canonically transformed variables. Both SPOT and DEM data was gathered for a tallgrass prairie near Manhattan, Kansas, and high resolution SPOT satellite images were integrated with DEM data. Two canonical variables derived from training samples were selected and it is suggested that canonically transformed data were superior to combined SPOT and DEM data. High resolution SPOT images and DEM data can be used to aid second-order soil surveys in grasslands.

  10. BOREAS Regional DEM in Raster Format and AEAC Projection

    NASA Technical Reports Server (NTRS)

    Knapp, David; Verdin, Kristine; Hall, Forrest G. (Editor)

    2000-01-01

    This data set is based on the GTOPO30 Digital Elevation Model (DEM) produced by the United States Geological Survey EROS Data Center (USGS EDC). The BOReal Ecosystem-Atmosphere Study (BOREAS) region (1,000 km x 1000 km) was extracted from the GTOPO30 data and reprojected by BOREAS staff into the Albers Equal-Area Conic (AEAC) projection. The pixel size of these data is 1 km. The data are stored in binary, image format files.

  11. Mapping debris-flow hazard in Honolulu using a DEM

    USGS Publications Warehouse

    Ellen, Stephen D.; Mark, Robert K.

    1993-01-01

    A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree of hazard over the area.

  12. Development of a 'bare-earth' SRTM DEM product

    NASA Astrophysics Data System (ADS)

    O'Loughlin, Fiachra; Paiva, Rodrigo; Durand, Michael; Alsdorf, Douglas; Bates, Paul

    2015-04-01

    We present the methodology and results from the development of a near-global 'bare-earth' Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM) data. Digital Elevation Models are the most important input for hydraulic modelling, as the DEM quality governs the accuracy of the model outputs. While SRTM is currently the best near-globally [60N to 60S] available DEM, it requires adjustments to reduce the vegetation contamination and make it useful for hydrodynamic modelling over heavily vegetated areas (e.g. tropical wetlands). Unlike previous methods of accounting for vegetation contamination, which concentrated on correcting relatively small areas and usually applied a static adjustment, we account for vegetation contamination globally and apply a spatial varying correction, based on information about canopy height and density. In creating the final 'bare-earth' SRTM DEM dataset, we produced three different 'bare-earth' SRTM products. The first applies global parameters, while the second and third products apply parameters that are regionalised based on either climatic zones or vegetation types, respectively. We also tested two different canopy density proxies of different spatial resolution. Using ground elevations obtained from the ICESat GLA14 satellite altimeter, we calculate the residual errors for the raw SRTM and the three 'bare-earth' SRTM products and compare performances. The three 'bare-earth' products all show large improvements over the raw SRTM in vegetated areas with the overall mean bias reduced by between 75 and 92% from 4.94 m to 0.40 m. The overall standard deviation is reduced by between 29 and 33 % from 7.12 m to 4.80 m. As expected, improvements are higher in areas with denser vegetation. The final 'bare-earth' SRTM dataset is available at 3 arc-second with lower vertical height errors and less noise than the original SRTM product.

  13. Ein statistisches Modell zum Einfluß der thermischen Bewegung auf NMR-Festkörperspektren

    NASA Astrophysics Data System (ADS)

    Ploss, W.; Freude, D.; Pfeifer, H.; Schmiedel, H.

    Es wird ein statistisches Modell zum Einfluß der thermischen Bewegung auf die NMR-Linienform vorgestellt, das die Verschmälerung von Festkörper-Spektren bei wachsender Temperatur beschreibt. Das Modell geht von der Annahme aus, daß nach einer Ortsveränderung eines Kerns infolge thermischer Bewegung jede beliebige Kernresonanzfrequenz mit der durch das Festkörperspektrum vorgegebenen Wahrscheinlichkeit angenommen werden kann. Am Beispiel der Festkörper-Gaußlinie wird der Unterschied zu dem bekannten Modell von ANDERSON und WEISS verdeutlicht.Translated AbstractA Statistical Model for the Influence of Thermal Motion on N. M. R. Spectra in SolidsA theory is proposed which allows to describe the narrowing of n. m. r.-line width in the presence of thermal motions of the spins. The model is based on the assumption, that the local resonance frequency of a given spin immediately after the jump is distributed according to the n. m. r.-line shape of the rigid lattice. The difference to the well-known ANDERSON-WEISS-model of spectral narrowing is demonstrated for a gaussian line shape.

  14. Efficient parallel CFD-DEM simulations using OpenMP

    NASA Astrophysics Data System (ADS)

    Amritkar, Amit; Deb, Surya; Tafti, Danesh

    2014-01-01

    The paper describes parallelization strategies for the Discrete Element Method (DEM) used for simulating dense particulate systems coupled to Computational Fluid Dynamics (CFD). While the field equations of CFD are best parallelized by spatial domain decomposition techniques, the N-body particulate phase is best parallelized over the number of particles. When the two are coupled together, both modes are needed for efficient parallelization. It is shown that under these requirements, OpenMP thread based parallelization has advantages over MPI processes. Two representative examples, fairly typical of dense fluid-particulate systems are investigated, including the validation of the DEM-CFD and thermal-DEM implementation with experiments. Fluidized bed calculations are performed on beds with uniform particle loading, parallelized with MPI and OpenMP. It is shown that as the number of processing cores and the number of particles increase, the communication overhead of building ghost particle lists at processor boundaries dominates time to solution, and OpenMP which does not require this step is about twice as fast as MPI. In rotary kiln heat transfer calculations, which are characterized by spatially non-uniform particle distributions, the low overhead of switching the parallelization mode in OpenMP eliminates the load imbalances, but introduces increased overheads in fetching non-local data. In spite of this, it is shown that OpenMP is between 50-90% faster than MPI.

  15. Validation of DEM prediction for granular avalanches on irregular terrain

    NASA Astrophysics Data System (ADS)

    Mead, Stuart R.; Cleary, Paul W.

    2015-09-01

    Accurate numerical simulation can provide crucial information useful for a greater understanding of destructive granular mass movements such as rock avalanches, landslides, and pyroclastic flows. It enables more informed and relatively low cost investigation of significant risk factors, mitigation strategy effectiveness, and sensitivity to initial conditions, material, or soil properties. In this paper, a granular avalanche experiment from the literature is reanalyzed and used as a basis to assess the accuracy of discrete element method (DEM) predictions of avalanche flow. Discrete granular approaches such as DEM simulate the motion and collisions of individual particles and are useful for identifying and investigating the controlling processes within an avalanche. Using a superquadric shape representation, DEM simulations were found to accurately reproduce transient and static features of the avalanche. The effect of material properties on the shape of the avalanche deposit was investigated. The simulated avalanche deposits were found to be sensitive to particle shape and friction, with the particle shape causing the sensitivity to friction to vary. The importance of particle shape, coupled with effect on the sensitivity to friction, highlights the importance of quantifying and including particle shape effects in numerical modeling of granular avalanches.

  16. DEM processing for the analysis of hydraulic hazards

    NASA Astrophysics Data System (ADS)

    Dresen, M.

    2003-04-01

    The digital analysis of hydrological processes and hydraulic hazards requires high data accuracy especially for topographic data that can not be insured by standard digital elevation models (DEMs). For this reason the terrain analysis and the analysis of topographical factors are highly significant for the modelling of hydrological processes. Most of the common GIS do not fulfill these requirements and do not allow detailed process oriented analysis. As a result, the estimation of hazard potential as well as the derivation of possible effects of catastrophic events are not possible. Due to this the improvement of DEM creation and expansion of placeable methods and functionalities have high priority in hydraulic hazard assessment. We can demonstrate that the quality of DEMs can be clearly improved with the help of different extensions and adaptations. The comparison of different flood events in Europe reveal the better accuracy of topographical factors and the derived hydrological parameters. In this way the simulation of hydrological processes and hydraulic hazards can be improved.

  17. Interpolation and elevation errors: the impact of the DEM resolution

    NASA Astrophysics Data System (ADS)

    Achilleos, Georgios A.

    2015-06-01

    Digital Elevation Models (DEMs) are developing and evolving at a fast pace, given the progress of computer science and technology. This development though, is not accompanied by an advancement of knowledge on the quality of the models and their indigenous inaccuracy. The user on most occasions is not aware of this quality thus in not aware of the correlating product uncertainty. Extensive research has been conducted - and still is - towards this direction. In the research presented in this paper there is an analysis of elevation errors behavior which are recorded in a DEM. The behavior of these elevation errors, is caused by altering the DEM resolution upon the application of the algorithm interpolation. Contour lines are used as entry data from a topographical map. Elevation errors are calculated in the positions of the initial entry data and wherever the elevation is known. The elevation errors that are recorded, are analyzed, in order to reach conclusions about their distribution and the way in which they occur.

  18. A NEW INSAR DERIVED DEM OF BLACK RAPIDS GLACIER

    NASA Astrophysics Data System (ADS)

    Shugar, D. H.; Rabus, B.; Clague, J. J.

    2009-12-01

    We have constructed a new digital elevation model representing the 1995 surface of surge-type Black Rapids Glacier and the surrounding central Alaska Range, using ERS-1/2 repeat-pass interferometry. First, we isolated the topographic phase from three interferograms with contrasting perpendicular baselines. Next we attempted to automatically unwrap this topographic phase but encountered numerous errors due to the terrain containing areas of poor coherence from fringe aliasing, radar layover or shadow. We then consistently corrected these persistent phase-unwrapping errors in all three interferograms using an iterative semi-automated approach that capitalizes on the multi-baseline nature of the data set. Over the surface of Black Rapids Glacier, the accuracy of the new DEM is estimated at better than +/- 12 m. Ground-surveyed spot elevations from 1995 corroborate this accuracy estimate. Comparison of the new DEM with a 1951 U.S. Geological Survey topographic map, and with ground survey data from other years, shows the gradual return of Black Rapids Glacier to pre-surge conditions. In the 44-year period between 1951 and 1995 the observed average steepening of the longitudinal profile is ~0.6°. The maximum elevation changes in the ablation and accumulation zones are -256 m and +75 m, respectively, suggesting corresponding average rates of elevation change of about -5.8 m/yr and +1.7 m/yr. These rates are 1.5-2 times higher than those indicated by the ground survey spot elevation measurements over the period 1975 to 2005. Considering the significant overlap of the two periods of measurement, the inferred average rates for 1951-1975 would have to be very large (-7.5 m/yr and +2.3 m/yr, respectively) for these two findings to be consistent. A second comparison with the recently released ASTER G-DEM (data from 2001) led to no glaciologically usable results due to major artifacts in the ASTER G-DEM. We therefore conclude that the 1951 U.S. Geological Survey map and the

  19. Kosten der Renaturierung

    NASA Astrophysics Data System (ADS)

    Hampicke, Ulrich

    Die Kapitel 3 bis 14 dieses Buches verdeutlichen die Verschiedenartigkeit der Renaturierungsprozesse in unterschiedlichen Ökosystemen und lassen keinen Zweifel daran, dass deren Kosten auch sehr weit auseinanderklaffen können. Die Kosten können gering sein, wenn die Renaturierung nur darin besteht, ein Biotop, das niemand braucht, sich selbst zu überlassen. Sie können aber auch sehr hoch sein, wenn etwa Sedimente eines Sees ausgebaggert und als Sondermüll entsorgt und aufwändige Klärkapazitäten installiert werden müssen.

  20. Zeit im Wandel der Zeit.

    NASA Astrophysics Data System (ADS)

    Aichelburg, P. C.

    Contents: Einleitung(P. C. Aichelburg). 1. Über Zeit, Bewegung und Veränderung (Aristoteles). 2. Ewigkeit und Zeit (Plotin). 3. Was ist die Zeit? (Augustinus). 4. Von der Zeit (Immanuel Kant). 5. Newtons Ansichten über Zeit, Raum und Bewegung (Ernst Mach). 6. Über die mechanische Erklärung irreversibler Vorgänge (Ludwig Boltzmann). 7. Das Maß der Zeit (Henri Poincaré). 8. Dauer und Intuition (Henri Bergson). 9. Die Geschichte des Unendlichkeitsproblems (Bertrand Russell). 10. Raum und Zeit (Hermann Minkowski). 11. Der Unterschied von Zeit und Raum (Hans Reichenbach). 12. Newtonscher und Bergsonscher Zeitbegriff (Norbert Wiener). 13. Die Bildung des Zeitbegriffs beim Kinde (JeanPiaget).14. Eine Bemerkung über die Beziehungen zwischen Relativitätstheorie und der idealistischen Philosophie (Kurt Gödel). 15. Der zweite Hauptsatz und der Unterschied von Vergangenheit und Zukunft (Carl Friedrich v. Weizsäcker). 16. Zeit als physikalischer Begriff (Friedrich Hund). 17. Zeitmessung und Zeitbegriff in der Astronomie (Otto Heckmann). 18. Kann die Zeit rückwärts gehen? (Martin Gardner). 19. Zeit und Zeiten (Ilya Prigogine, Isabelle Stengers). 20. Zeit als dynamische Größe in der Relativitätstheorie (P. C. Aichelburg).

  1. Assessment of Reference Height Models on Quality of Tandem-X dem

    NASA Astrophysics Data System (ADS)

    Mirzaee, S.; Motagh, M.; Arefi, H.

    2015-12-01

    The aim of this study is to investigate the effect of various Global Digital Elevation Models (GDEMs) in producing high-resolution topography model using TanDEM-X (TDX) Coregistered Single Look Slant Range Complex (CoSSC) images. We selected an image acquired on Jun 12th, 2012 over Doroud region in Lorestan, west of Iran and used 4 external digital elevation models in our processing including DLR/ASI X-SAR DEM (SRTM-X, 30m resolution), ASTER GDEM Version 2 (ASTER-GDEMV2, 30m resolution), NASA SRTM Version 4 (SRTM-V4, 90m resolution), and a local photogrammetry-based DEM prepared by National Cartographic Center (NCC DEM, 10m resolution) of Iran. InSAR procedure for DEM generation was repeated four times with each of the four external height references. The quality of each external DEM was initially assessed using ICESat filtered points. Then, the quality of, each TDX-based DEM was assessed using the more precise external DEM selected in the previous step. Results showed that both local (NCC) DEM and SRTM X-band performed the best (RMSE< 9m) for TDX-DEM generation. In contrast, ASTER GDEM v2 and SRTM C-band v4 showed poorer quality.

  2. Ökologische Grundlagen und limitierende Faktoren der Renaturierung

    NASA Astrophysics Data System (ADS)

    Rosenthal, Gert; Eichberg, Carsten

    In den dicht besiedelten und agrarisch besonders intensiv genutzten Regionen Mittel- und Westeuropas ist seit Ende des Zweiten Weltkrieges ein fortschreitender Verlust an naturnahen ökosystemen mit hoher biologischer Vielfalt zu verzeichnen. Spätestens seit den 1970er-Jahren ist daher die Neuschaffung und Wiederherstellung gefährdeter Lebensräume und Biozönosen zunehmend in den Mittelpunkt von Naturschutzmaßnahmen gerückt (Bakker 1989, Muller et al. 1998, Bakker und Berendse 1999). Aufgrund fehlender wissenschaftlicher Grundlagen und praktischer Erfahrungen wurden Renaturierungsmaßnahmen anfangs fast durchweg nach dem trial and error-Prinzip durchgeführt. Im Vordergrund standen dabei zunächst die Wiederherstellung adäquater abiotischer Standortbedingungen sowie die Reorganisation traditioneller Nutzungsmanagements. Bei Ersterem ging es neben der Wiedervernässung entwässerter Feuchtgebiete (Pfadenhauer und Grootjans 1999) vor allem darum, Eutrophierungseffekte zu beseitigen und die Produktivität des Standortes auf das Niveau der Zielgemeinschaft zurückzuführen (Gough und Marrs 1990, Oomes et al. 1996, Snow et al. 1997, Tallowin et al. 1998).

  3. 3D DEM analyses of the 1963 Vajont rock slide

    NASA Astrophysics Data System (ADS)

    Boon, Chia Weng; Houlsby, Guy; Utili, Stefano

    2013-04-01

    The 1963 Vajont rock slide has been modelled using the distinct element method (DEM). The open-source DEM code, YADE (Kozicki & Donzé, 2008), was used together with the contact detection algorithm proposed by Boon et al. (2012). The critical sliding friction angle at the slide surface was sought using a strength reduction approach. A shear-softening contact model was used to model the shear resistance of the clayey layer at the slide surface. The results suggest that the critical sliding friction angle can be conservative if stability analyses are calculated based on the peak friction angles. The water table was assumed to be horizontal and the pore pressure at the clay layer was assumed to be hydrostatic. The influence of reservoir filling was marginal, increasing the sliding friction angle by only 1.6˚. The results of the DEM calculations were found to be sensitive to the orientations of the bedding planes and cross-joints. Finally, the failure mechanism was investigated and arching was found to be present at the bend of the chair-shaped slope. References Boon C.W., Houlsby G.T., Utili S. (2012). A new algorithm for contact detection between convex polygonal and polyhedral particles in the discrete element method. Computers and Geotechnics, vol 44, 73-82, doi.org/10.1016/j.compgeo.2012.03.012. Kozicki, J., & Donzé, F. V. (2008). A new open-source software developed for numerical simulations using discrete modeling methods. Computer Methods in Applied Mechanics and Engineering, 197(49-50), 4429-4443.

  4. A global database of volcano edifice morphometry using SRTM DEMs

    NASA Astrophysics Data System (ADS)

    Grosse, P.; van Wyk de Vries, B.; Petrinovic, I. A.; Euillades, P. A.

    2009-12-01

    The morphometry of volcanic edifices reflects the aggradational and degradational processes that interact during their evolution. In association with VOGRIPA, a global risk identification project, we are currently constructing a database on the morphometry of volcanic edifices using digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM). Our aim is to compile and make available a global database of morphometric parameters that characterize the shape and size of volcanic edifices. The 90-meter SRTM DEM is presently the best public-access DEM dataset for this task because of its near-global coverage and spatial resolution that is high enough for the analysis of composite volcanic edifices. The Smithsonian Institution database lists 1536 active/potentially active volcanoes worldwide. Of these, ~900 volcano edifices can be analyzed with the SRTM DEMs, discarding volcanoes not covered by the dataset above latitudes 60°N and 56°S, submarine volcanoes, volcanoes with mostly negative topographies (i.e. calderas, maars) and monogenetic cones and domes, which are too small to accurately study with the 90-meter resolution. Morphometric parameters are acquired using an expressly written IDL-language code named MORVOLC. Edifice outline is determined via a semi-automated algorithm that identifies slope-breaks between user-estimated maximum and minimum outlines. Thus, volcanic edifices as topographic entities are considered, excluding aprons or ring plains and other far-reaching volcanic products. Several morphometric parameters are computed which characterize edifice size and shape. Size parameters are height (from base to summit), volume, base and summit areas and widths (average, minimum, maximum). Plan shape is summarized using two independent dimensionless indexes that describe the shape of the elevation contours, ellipticity (quantifies the elongation of each contour) and irregularity (quantifies the irregularity or complexity of each contour

  5. Processing, validating, and comparing DEMs for geomorphic application on the Puna de Atacama Plateau, northwest Argentina

    NASA Astrophysics Data System (ADS)

    Purinton, Benjamin; Bookhagen, Bodo

    2016-04-01

    This study analyzes multiple topographic datasets derived from various remote-sensing methods from the Pocitos Basin of the central Puna Plateau in northwest Argentina at the border to Chile. Here, the arid climate and clear atmospheric conditions and lack of vegetation provide ideal conditions for remote sensing and Digital Elevation Model (DEM) comparison. We compare the following freely available DEMs: SRTM-X (spatial resolution of ~30 m), SRTM-C v4.1 (90 m), and ASTER GDEM2 (30 m). Additional DEMs for comparison are generated from optical and radar datasets acquired freely (ASTER Level 1B stereo pairs and Sentinal-1A radar), through research agreements (RapidEye Level 1B scenes, ALOS radar, and ENVISAT radar), and through commercial sources (TerraSAR-X / TanDEM-X radar). DEMs from ASTER (spatial resolution of 15 m) and RapidEye (~5-10 m) optical datasets are produced by standard photogrammetric techniques and have been post-processed for validation and alignment purposes. Because RapidEye scenes are captured at a low incidence angle (<20°) and stereo pairs are unavailable, merging and averaging methods of two to four overlapping scenes is explored for effective DEM generation. Sentinal-1A, TerraSAR-X / TanDEM-X, ALOS, and ENVISAT radar data is processed through interferometry resulting in DEMs with spatial resolutions ranging from 5 to 30 meters. The SRTM-X dataset serves as a control in the creation of further DEMs, as it is widely used in the geosciences and represents the highest-quality DEM currently available. All DEMs are validated against over 400,000 differential GPS (dGPS) measurements gathered during four field campaigns in 2012 and 2014 to 2016. Of these points, more than 250,000 lie within the Pocitos Basin with average vertical and horizontal accuracies of 0.95 m and 0.69 m, respectively. Dataset accuracy is judged by the lowest standard deviations of elevation compared with the dGPS data and with the SRTM-X control DEM. Of particular interest in

  6. [Van-der-Woude Syndrome].

    PubMed

    Del Frari, B; Amort, M; Janecke, A R; Schutte, B C; Piza-Katzer, H

    2008-01-01

    We report on two families with different expression of a Van-der-Woude-Syndrome (VWS) and with proven mutation of the IRF6- gene. The Van-der-Woude syndrome is a rare disease, typically consisting of congenital pits of the lower lip in combination with cleft lip or cleft palate or both. The Van-der-Woude syndrome is an autosomal dominant syndrome with variable expression. The penetrance is between 0,89 and 0,99. It is important to establish the correct diagnosis by careful investigation of patients with cleft lip or cleft palate and their parents. Genetic counselling is recommended in such cases. PMID:18095255

  7. The Importance of Precise Digital Elevation Models (DEM) in Modelling Floods

    NASA Astrophysics Data System (ADS)

    Demir, Gokben; Akyurek, Zuhal

    2016-04-01

    Digital elevation Models (DEM) are important inputs for topography for the accurate modelling of floodplain hydrodynamics. Floodplains have a key role as natural retarding pools which attenuate flood waves and suppress flood peaks. GPS, LIDAR and bathymetric surveys are well known surveying methods to acquire topographic data. It is not only time consuming and expensive to obtain topographic data through surveying but also sometimes impossible for remote areas. In this study it is aimed to present the importance of accurate modelling of topography for flood modelling. The flood modelling for Samsun-Terme in Blacksea region of Turkey is done. One of the DEM is obtained from the point observations retrieved from 1/5000 scaled orthophotos and 1/1000 scaled point elevation data from field surveys at x-sections. The river banks are corrected by using the orthophotos and elevation values. This DEM is named as scaled DEM. The other DEM is obtained from bathymetric surveys. 296 538 number of points and the left/right bank slopes were used to construct the DEM having 1 m spatial resolution and this DEM is named as base DEM. Two DEMs were compared by using 27 x-sections. The maximum difference at thalweg of the river bed is 2m and the minimum difference is 20 cm between two DEMs. The channel conveyance capacity in base DEM is larger than the one in scaled DEM and floodplain is modelled in detail in base DEM. MIKE21 with flexible grid is used in 2- dimensional shallow water flow modelling. The model by using two DEMs were calibrated for a flood event (July 9, 2012). The roughness is considered as the calibration parameter. From comparison of input hydrograph at the upstream of the river and output hydrograph at the downstream of the river, the attenuation is obtained as 91% and 84% for the base DEM and scaled DEM, respectively. The time lag in hydrographs does not show any difference for two DEMs and it is obtained as 3 hours. Maximum flood extents differ for the two DEMs

  8. Pre-Conditioning Optmization Methods and Display for Mega-Pixel DEM Reconstructions

    NASA Astrophysics Data System (ADS)

    Sette, A. L.; DeLuca, E. E.; Weber, M. A.; Golub, L.

    2004-05-01

    The Atmospheric Imaging Assembly (AIA) for the Solar Dynamics Observatory will provide an unprecedented rate of mega-pixel solar corona data. This hastens the need for faster differential emission measure (DEM) reconstruction methods, as well as scientifically useful ways of displaying this information for mega-pixel datasets. We investigate pre-conditioning methods, which optimize DEM reconstruction by making an informed initial DEM guess that takes advantage of the sharing of DEM information among the pixels in an image. In addition, we evaluate the effectiveness of different DEM image display options, including single temperature emission maps and time-progression DEM movies. This work is supported under contract SP02D4301R to the Lockheed Martin Corp.

  9. Biochips und ihr Einsatz in der Lebensmittelanalytik

    NASA Astrophysics Data System (ADS)

    Huber, Ingrid; Zeltz, Patric

    Mit der Verbreitung des Begriffes "Biochip“ in den biotechnologischen Medien wurde Ende der 1990er-Jahre zunächst der Eindruck erweckt, dass die Computerelektronik in die molekularbiologischen Anwendungen eingestiegen ist [18]. In nur wenigen Jahren hat sich die Biochiptechnologie zu einem Verfahren entwickelt, das aus der molekularbiologischen Grundlagenforschung nicht mehr wegzudenken ist und über eine Vielzahl von Einsatzbereichen verfügt. Die Biochiptechnologie ermöglicht die Miniaturisierung von DNA-, RNA- bzw. Proteinanalytik in hochparallelen Formaten. Dieser hohe Parallelisierungsgrad ist einer der wesentlichen Vorteile dieser Technik gegenüber klassischen molekularbiologischen Methoden. Sie wird heutzutage vor allem in der Genomforschung eingesetzt, für Genexpressionsstudien, zum Screening von single nucleotide polymorphisms (SNPs), in der pharmakogenetischen Forschung sowie in der Erforschung von Erbkrankheiten und in der Krebsforschung [1, 7, 19]. Neben vielen weiteren Bereichen finden Biochips auch spezielle Anwendungen in der Lebensmittelanalytik.

  10. A photogrammetric DEM of Greenland based on 1978-1987 aerial photos: validation and integration with laser altimetry and satellite-derived DEMs

    NASA Astrophysics Data System (ADS)

    Korsgaard, N. J.; Kjaer, K. H.; Nuth, C.; Khan, S. A.

    2014-12-01

    Here we present a DEM of Greenland covering all ice-free terrain and the margins of the GrIS and local glaciers and ice caps. The DEM is based on the 3534 photos used in the aero-triangulation which were recorded by the Danish Geodata Agency (then the Geodetic Institute) in survey campaigns spanning the period 1978-1987. The GrIS is covered tens of kilometers into the interior due to the large footprints of the photos (30 x 30 km) and control provided by the aero-triangulation. Thus, the data are ideal for providing information for analysis of ice marginal elevation change and also control for satellite-derived DEMs.The results of the validation, error assessments and predicted uncertainties are presented. We test the DEM using Airborne Topographic Mapper (IceBridge ATM) as reference data; evaluate the a posteriori covariance matrix from the aero-triangulation; and co-register DEM blocks of 50 x 50 km to ICESat laser altimetry in order to evaluate the coherency.We complement the aero-photogrammetric DEM with modern laser altimetry and DEMs derived from stereoscopic satellite imagery (AST14DMO) to examine the mass variability of the Northeast Greenland Ice Stream (NEGIS). Our analysis suggests that dynamically-induced mass loss started around 2003 and continued throughout 2014.

  11. Numerical Simulation of High Velocity Impact Phenomenon by the Distinct Element Method (dem)

    NASA Astrophysics Data System (ADS)

    Tsukahara, Y.; Matsuo, A.; Tanaka, K.

    2007-12-01

    Continuous-DEM (Distinct Element Method) for impact analysis is proposed in this paper. Continuous-DEM is based on DEM (Distinct Element Method) and the idea of the continuum theory. Numerical simulations of impacts between SUS 304 projectile and concrete target has been performed using the proposed method. The results agreed quantitatively with the impedance matching method. Experimental elastic-plastic behavior with compression and rarefaction wave under plate impact was also qualitatively reproduced, matching the result by AUTODYN®.

  12. Der evolutionäre Naturalismus in der Ethik

    NASA Astrophysics Data System (ADS)

    Kaiser, Marie I.

    Charles Darwin hat eindrucksvoll gezeigt, dass der Mensch ebenso wie alle anderen Lebewesen ein Produkt der biologischen Evolution ist. Die sich an Darwin anschließende Forschung hat außerdem plausibel gemacht, dass sich nicht nur viele der körperlichen Merkmale des Menschen, sondern auch (zumindest einige) seiner Verhaltensdispositionen in adaptiven Selektionsprozessen herausgebildet haben. Die Vorstellung, dass auch die menschliche Moralität evolutionär bedingt ist, scheint daher auf den ersten Blick ganz überzeugend. Schließlich hat die Evolutionstheorie in den vergangenen Jahrzehnten in vielen Bereichen (auch außerhalb der Biologie) ihre weitreichende Bedeutung unter Beweis gestellt. Warum sollte, so könnte man beispielsweise fragen, gerade die Fähigkeit des Menschen, moralische Normen aufzustellen und gemäß ihnen zu handeln, nicht evolutionär erklärt werden können? Und warum sollte eine solche evolutionäre Erklärung der menschlichen Moralität irrelevant für die Rechtfertigung moralischer Normen sein? Warum sollte die Ethik eine Bastion der Philosophen bleiben, für die evolutionsbiologische Forschungsergebnisse über den Menschen und seine nächsten Verwandten keinerlei Relevanz besitzen?

  13. DEM modeling of flexible structures against granular material avalanches

    NASA Astrophysics Data System (ADS)

    Lambert, Stéphane; Albaba, Adel; Nicot, François; Chareyre, Bruno

    2016-04-01

    This article presents the numerical modeling of flexible structures intended to contain avalanches of granular and coarse material (e.g. rock slide, a debris slide). The numerical model is based on a discrete element method (YADE-Dem). The DEM modeling of both the flowing granular material and the flexible structure are detailed before presenting some results. The flowing material consists of a dry polydisperse granular material accounting for the non-sphericity of real materials. The flexible structure consists in a metallic net hanged on main cables, connected to the ground via anchors, on both sides of the channel, including dissipators. All these components were modeled as flexible beams or wires, with mechanical parameters defined from literature data. The simulation results are presented with the aim of investigating the variability of the structure response depending on different parameters related to the structure (inclination of the fence, with/without brakes, mesh size opening), but also to the channel (inclination). Results are then compared with existing recommendations in similar fields.

  14. DEM, tide and velocity over sulzberger ice shelf, West Antarctica

    USGS Publications Warehouse

    Baek, S.; Shum, C.K.; Lee, H.; Yi, Y.; Kwoun, Oh-Ig; Lu, Zhiming; Braun, Andreas

    2005-01-01

    Arctic and Antarctic ice sheets preserve more than 77% of the global fresh water and could raise global sea level by several meters if completely melted. Ocean tides near and under ice shelves shifts the grounding line position significantly and are one of current limitations to study glacier dynamics and mass balance. The Sulzberger ice shelf is an area of ice mass flux change in West Antarctica and has not yet been well studied. In this study, we use repeat-pass synthetic aperture radar (SAR) interferometry data from the ERS-1 and ERS-2 tandem missions for generation of a high-resolution (60-m) Digital Elevation Model (DEM) including tidal deformation detection and ice stream velocity of the Sulzberger Ice Shelf. Other satellite data such as laser altimeter measurements with fine foot-prints (70-m) from NASA's ICESat are used for validation and analyses. The resulting DEM has an accuracy of-0.57??5.88 m and is demonstrated to be useful for grounding line detection and ice mass balance studies. The deformation observed by InSAR is found to be primarily due to ocean tides and atmospheric pressure. The 2-D ice stream velocities computed agree qualitatively with previous methods on part of the Ice Shelf from passive microwave remote-sensing data (i.e., LANDSAT). ?? 2005 IEEE.

  15. a Near-Global Bare-Earth dem from Srtm

    NASA Astrophysics Data System (ADS)

    Gallant, J. C.; Read, A. M.

    2016-06-01

    The near-global elevation product from NASA's Shuttle Radar Topographic Mission (SRTM) has been widely used since its release in 2005 at 3 arcsecond resolution and the release of the 1 arcsecond version in late 2014 means that the full potential of the SRTM DEM can now be realised. However the routine use of SRTM for analytical purposes such as catchment hydrology, flood inundation, habitat mapping and soil mapping is still seriously impeded by the presence of artefacts in the data, primarily the offsets due to tree cover and the random noise. This paper describes the algorithms being developed to remove those offsets, based on the methods developed to produce the Australian national elevation model from SRTM data. The offsets due to trees are estimated using the GlobeLand30 (National Geomatics Center of China) and Global Forest Change (University of Maryland) products derived from Landsat, along with the ALOS PALSAR radar image data (JAXA) and the global forest canopy height map (NASA). The offsets are estimated using several processes and combined to produce a single continuous tree offset layer that is subtracted from the SRTM data. The DEM products will be made freely available on completion of the first draft product, and the assessment of that product is expected to drive further improvements to the methods.

  16. A seamless, high-resolution digital elevation model (DEM) of the north-central California coast

    USGS Publications Warehouse

    Foxgrover, Amy C.; Barnard, Patrick L.

    2012-01-01

    A seamless, 2-meter resolution digital elevation model (DEM) of the north-central California coast has been created from the most recent high-resolution bathymetric and topographic datasets available. The DEM extends approximately 150 kilometers along the California coastline, from Half Moon Bay north to Bodega Head. Coverage extends inland to an elevation of +20 meters and offshore to at least the 3 nautical mile limit of state waters. This report describes the procedures of DEM construction, details the input data sources, and provides the DEM for download in both ESRI Arc ASCII and GeoTIFF file formats with accompanying metadata.

  17. A New DEM Generalization Method Based on Watershed and Tree Structure

    PubMed Central

    Chen, Yonggang; Ma, Tianwu; Chen, Xiaoyin; Chen, Zhende; Yang, Chunju; Lin, Chenzhi; Shan, Ligang

    2016-01-01

    The DEM generalization is the basis of multi-dimensional observation, the basis of expressing and analyzing the terrain. DEM is also the core of building the Multi-Scale Geographic Database. Thus, many researchers have studied both the theory and the method of DEM generalization. This paper proposed a new method of generalizing terrain, which extracts feature points based on the tree model construction which considering the nested relationship of watershed characteristics. The paper used the 5 m resolution DEM of the Jiuyuan gully watersheds in the Loess Plateau as the original data and extracted the feature points in every single watershed to reconstruct the DEM. The paper has achieved generalization from 1:10000 DEM to 1:50000 DEM by computing the best threshold. The best threshold is 0.06. In the last part of the paper, the height accuracy of the generalized DEM is analyzed by comparing it with some other classic methods, such as aggregation, resample, and VIP based on the original 1:50000 DEM. The outcome shows that the method performed well. The method can choose the best threshold according to the target generalization scale to decide the density of the feature points in the watershed. Meanwhile, this method can reserve the skeleton of the terrain, which can meet the needs of different levels of generalization. Additionally, through overlapped contour contrast, elevation statistical parameters and slope and aspect analysis, we found out that the W8D algorithm performed well and effectively in terrain representation. PMID:27517296

  18. A New DEM Generalization Method Based on Watershed and Tree Structure.

    PubMed

    Chen, Yonggang; Ma, Tianwu; Chen, Xiaoyin; Chen, Zhende; Yang, Chunju; Lin, Chenzhi; Shan, Ligang

    2016-01-01

    The DEM generalization is the basis of multi-dimensional observation, the basis of expressing and analyzing the terrain. DEM is also the core of building the Multi-Scale Geographic Database. Thus, many researchers have studied both the theory and the method of DEM generalization. This paper proposed a new method of generalizing terrain, which extracts feature points based on the tree model construction which considering the nested relationship of watershed characteristics. The paper used the 5 m resolution DEM of the Jiuyuan gully watersheds in the Loess Plateau as the original data and extracted the feature points in every single watershed to reconstruct the DEM. The paper has achieved generalization from 1:10000 DEM to 1:50000 DEM by computing the best threshold. The best threshold is 0.06. In the last part of the paper, the height accuracy of the generalized DEM is analyzed by comparing it with some other classic methods, such as aggregation, resample, and VIP based on the original 1:50000 DEM. The outcome shows that the method performed well. The method can choose the best threshold according to the target generalization scale to decide the density of the feature points in the watershed. Meanwhile, this method can reserve the skeleton of the terrain, which can meet the needs of different levels of generalization. Additionally, through overlapped contour contrast, elevation statistical parameters and slope and aspect analysis, we found out that the W8D algorithm performed well and effectively in terrain representation. PMID:27517296

  19. Monte Carlo Markov chain DEM reconstruction of isothermal plasmas

    NASA Astrophysics Data System (ADS)

    Landi, E.; Reale, F.; Testa, P.

    2012-02-01

    Context. Recent studies carried out with SOHO and Hinode high-resolution spectrometers have shown that the plasma in the off-disk solar corona is close to isothermal. If confirmed, these findings may have significant consequences for theoretical models of coronal heating. However, these studies have been carried out with diagnostic techniques whose ability to reconstruct the plasma distribution with temperature has not been thoroughly tested. Aims: In this paper, we carry out tests on the Monte Carlo Markov chain (MCMC) technique with the aim of determining: 1) its ability to retrieve isothermal plasmas from a set of spectral line intensities, with and without random noise; 2) to what extent can it discriminate between an isothermal solution and a narrow multithermal distribution; and 3) how well it can detect multiple isothermal components along the line of sight. We also test the effects of 4) atomic data uncertainties on the results, and 5) the number of ions whose lines are available for the DEM reconstruction. Methods: We first use the CHIANTI database to calculate synthetic spectra from different thermal distributions: single isothermal plasmas, multithermal plasmas made of multiple isothermal components, and multithermal plasmas with a Gaussian DEM distribution with variable width. We then apply the MCMC technique on each of these synthetic spectra, so that the ability of the MCMC technique at reconstructing the original thermal distribution can be evaluated. Next, we add a random noise to the synthetic spectra, and repeat the exercise, in order to determine the effects of random errors on the results. We also we repeat the exercise using a different set of atomic data from those used to calculate synthetic line intensities, to understand the robustness of the results against atomic physics uncertainties. The size of the temperature bin of the MCMC reconstruction is varied in all cases, in order to determine the optimal width. Results: We find that the MCMC

  20. High-precise DEM Generation Using Envisat/ERS-2 Cross-interferometry

    NASA Astrophysics Data System (ADS)

    Lee, W.; Jung, H.; Lu, Z.; Zhang, L.

    2010-12-01

    Cross-interferometric synthetic aperture radar (CInSAR) technique from ERS-2 and Envisat images is capable of generating submeter-accuracy digital elevation model (DEM). However, it is very difficult to produce high-quality CInSAR-derived DEM due to the difference in the azimuth and range pixel size between ERS-2 and Envisat images as well as the small height ambiguity of CInSAR interferogram. In this study, we have proposed an efficient method to overcome the problems, produced a high-quality DEM over northern Alaska, and assessed the accuracy of the CInSAR-derived DEM with an airborne InSAR-derived DEM, which has the spatial resolution of 5 meters, from U.S. Geological Survey. In the proposed method, azimuth common band filtering in the radar raw data processing and DEM-assisted SAR coregistration are applied to mitigate the mis-registration due to the difference in the azimuth and range pixel size and large baseline, and differential SAR interferogram (DInSAR) created by using the low-quality DEM is used for reducing the unwrapping error occurred by the high fringe rate of CInSAR interferogram. From accuracy assessment, in flat area, the precision of CInSAR-derived DEM was approximately 4.2 m and 70cm in the horizontal and vertical directions, respectively, and the ground resolution estimated by the wave number analysis was about 15m. However, most errors occurred in around water area (like lake). And generating time is different between Airborne DEM (July, 2002) and CInSAR DEM(January, 2008). Focus on land area (not around water), vertical accuracy is highly improved about submeter unit. Our results indicate that high-precise DEM of submeter-accuracy can be generated by the proposed method.

  1. Shuttle radar DEM hydrological correction for erosion modelling in small catchments

    NASA Astrophysics Data System (ADS)

    Jarihani, Ben; Sidle, Roy; Bartley, Rebecca

    2016-04-01

    Digital Elevation Models (DEMs) that accurately replicate both landscape form and processes are critical to support modelling of environmental processes. Catchment and hillslope scale runoff and sediment processes (i.e., patterns of overland flow, infiltration, subsurface stormflow and erosion) are all topographically mediated. In remote and data-scarce regions, high resolution DEMs (LiDAR) are often not available, and moderate to course resolution digital elevation models (e.g., SRTM) have difficulty replicating detailed hydrological patterns, especially in relatively flat landscapes. Several surface reconditioning algorithms (e.g., Smoothing) and "Stream burning" techniques (e.g., Agree or ANUDEM), in conjunction with representation of the known stream networks, have been used to improve DEM performance in replicating known hydrology. Detailed stream network data are not available at regional and national scales, but can be derived at local scales from remotely-sensed data. This research explores the implication of high resolution stream network data derived from Google Earth images for DEM hydrological correction, instead of using course resolution stream networks derived from topographic maps. The accuracy of implemented method in producing hydrological-efficient DEMs were assessed by comparing the hydrological parameters derived from modified DEMs and limited high-resolution airborne LiDAR DEMs. The degree of modification is dominated by the method used and availability of the stream network data. Although stream burning techniques improve DEMs hydrologically, these techniques alter DEM characteristics that may affect catchment boundaries, stream position and length, as well as secondary terrain derivatives (e.g., slope, aspect). Modification of a DEM to better reflect known hydrology can be useful, however, knowledge of the magnitude and spatial pattern of the changes are required before using a DEM for subsequent analyses.

  2. Near-automatic generation of lava dome DEMs from photos

    NASA Astrophysics Data System (ADS)

    James, M. R.; Varley, N.

    2012-04-01

    Acquiring accurate digital elevation models (DEMs) of growing lava domes is critical for hazard assessment. However, most techniques require expertise and time (e.g. photogrammetry) or expensive equipment (e.g. laser scanning and radar-based techniques). Here, we use a photo-based approach developed within the computer vision community that offers the potential for near-automatic DEM construction using a consumer-grade digital camera and freely available software. The technique is based on a combination of structure-from-motion and multi-view stereo algorithms (SfM-MVS) and can generate dense 3D point clouds (millions of points) from multiple photographs of a scene taken from different positions. Processing is carried out by automated 'reconstruction pipeline' software downloadable from the internet, e.g. http://blog.neonascent.net/archives/bundler-photogrammetry-package/. Such reconstructions are initally un-scaled and un-oriented so additional software (http://www.lancs.ac.uk/ staff/jamesm/software/sfm_georef.htm) has been developed to permit scaling or full georeferencing. Although this step requires the presence of some control points or knowledge of scale within the scene, it does not have the relatively strict image acquisition and control requirements of traditional photogrammetry. For accuracy and to allow error analysis, georeferencing observations are made within the image set, rather than requiring feature matching within the point cloud. Here we demonstrate the results of using the technique for deriving 3D models of the Volcán de Colima lava dome. 5 image sets have been collected by different people over a period of 12 months during overflights in a light aircraft. Although the resulting imagery is of variable quality for 3D reconstruction, useful data can be extracted from each set. Scaling and georeferencing is carried out using a combination of ortho-imagery (downloaded from Bing) and a few GPS points. Overall precisions are ~1 m and DEM qualities

  3. Extraction of Hydrological Proximity Measures from DEMs using Parallel Processing

    SciTech Connect

    Tesfa, Teklu K.; Tarboton, David G.; Watson, Daniel W.; Schreuders, Kimberly A.; Baker, Matthew M.; Wallace, Robert M.

    2011-12-01

    Land surface topography is one of the most important terrain properties which impact hydrological, geomorphological, and ecological processes active on a landscape. In our previous efforts to develop a soil depth model based upon topographic and land cover variables, we extracted a set of hydrological proximity measures (HPMs) from a Digital Elevation Model (DEM) as potential explanatory variables for soil depth. These HPMs may also have other, more general modeling applicability in hydrology, geomorphology and ecology, and so are described here from a general perspective. The HPMs we derived are variations of the distance up to ridge points (cells with no incoming flow) and variations of the distance down to stream points (cells with a contributing area greater than a threshold), following the flow path. These HPMs were computed using the D-infinity flow model that apportions flow between adjacent neighbors based on the direction of steepest downward slope on the eight triangular facets constructed in a 3 x 3 grid cell window using the center cell and each pair of adjacent neighboring grid cells in turn. The D-infinity model typically results in multiple flow paths between 2 points on the topography, with the result that distances may be computed as the minimum, maximum or average of the individual flow paths. In addition, each of the HPMs, are calculated vertically, horizontally, and along the land surface. Previously, these HPMs were calculated using recursive serial algorithms which suffered from stack overflow problems when used to process large datasets, limiting the size of DEMs that could be analyzed using that method to approximately 7000 x 7000 cells. To overcome this limitation, we developed a message passing interface (MPI) parallel approach for calculating these HPMs. The parallel algorithms of the HPMs spatially partition the input grid into stripes which are each assigned to separate processes for computation. Each of those processes then uses a

  4. Ganymede crater dimensions from Galileo-based DEMs

    NASA Astrophysics Data System (ADS)

    Bray, V. J.; Schenk, P.; Melosh, H. J.; McEwen, A. S.; Morgan, J. V.; Collins, G. S.

    2010-12-01

    Images returned from the Voyager mission have allowed the analysis of crater morphology on the icy satellites and the construction of both diameter and depth-related scaling laws. Higher resolution Galileo data has since been used to update the diameter-related scaling trends, and also crater depths on the basis of shadow measurements. Our work adds to this wealth of data with new depth and slope information extracted from digital elevation models (DEMs) created from Galileo Solid State Imager (SSI) images, with the use of the stereo scene-recognition algorithm developed by Schenk et al. (2004), and from photoclinometry incorporating the combined lunar-Lambert photometric function as defined by McEwen et al. (1991). We profiled ~80 craters, ranging from 4 km to 100 km in diameter. Once each DEM of a crater was obtained, spurious patterns or shape distortions created by radiation noise or data compression artifacts were removed through the use of standard image noise filters, and manually by visual inspection of the DEM and original image(s). Terrain type was noted during profile collection so that any differences in crater trends on bright and dark terrains could be documented. Up to 16 cross-sectional profiles were taken across each crater so that the natural variation of crater dimensions with azimuth could be included in the measurement error. This already incorporates a systematic error on depth measurements of ~ 5%, an improvement from Voyager depth uncertainties of 10-30%. The crater diameter, depth, wall slope, rim height, central uplift height, diameter and slope, and central pit depth, diameter and slope were measured from each profile. Our measurements of feature diameters and of crater depth are consistent with already published results based on measurement from images and shadow lengths. We will present example topographic profiles and scaling trends, specifically highlighting the new depth and slope information for different crater types on Ganymede

  5. Einleitung

    NASA Astrophysics Data System (ADS)

    Walther-Klaus, Ellen

    Deutschland hat sich in den letzten Jahrzehnten den internationalen Ruf erworben, auf dem Gebiet der Technologie führend zu sein. Große, weitreichende Erfindungen sind in Deutschland gemacht worden. Viele Nobelpreise gehen nach Deutschland: Robert Bosch, Nikolaus Otto und Konrad Zuse gehören genauso zu den großen Erfindern, wie Melitta Bentz und Emmy Noether. 85 % aller Nobelpreise, die seit 1901 nach Deutschland gingen, sind in den Kategorien Chemie, Physik und Medizin vergeben worden. Allein im Jahr 2007 wurden in Deutschland fast 50.000 Patente angemeldet.

  6. Sinn und Möglichkeiten der Theoretischen Physik. Zum 300. Jahrestag von Newtons Philosophiae Naturalis Principia Mathematica

    NASA Astrophysics Data System (ADS)

    Rompe, R.; Thiessen, P. A.; Treder, H.-J.

    Die Newtonschen Prinzipien und die aus ihnen gewonnene Erkenntnis der Existenz von Elementarkonstanten nach Planck, Einstein und Bohr erweisen sich zunehmend als tragfähiges Fundament nicht nur der Physik und ihrer Anwendung in der Technik, sondern überhaupt aller exakten Wissenschaften in breitestem Sinne des Wortes.Die physikalisch inhaltliche Klärung der Begriffe erfolgt seit Newton in engem Verbund mit der Entwicklung mathematischer Methoden. Diese Kombination erweist sich weiterhin als produktiv und sichert den Fortschritt der Physik und der exakten Wissenschaften.Wohl alle Probleme, die im Bereich der Technik Bedeutung haben können, lassen sich bei entsprechendem Aufwand bereits mit dem vorhandenen Fundus an Erkenntnissen und Methoden erfolgreich angehen.Der in der Wirklichkeit verankerte Zusammenhang von Gesetz und Zufall erweist sich als eine Manifestation der Dialektik in der Natur. Es gibt keinen absoluten Zufall. Sie kommt in allen Zweigen der Physik, nicht nur in der Thermodynamik und Quantenphysik, zutage, und muß bereits auf dem Niveau der Newtonschen Prinzipien und der Elementarkonstanten behandelt werden.Die theoretische Physik, so wie sie von Newton initiiert worden ist, wurde so angelegt, daß sie alle Seiten der Wirklichkeit, so weit sie in die Kompetenz der Physik fallen, umfaßt. Es besteht darum kein Gegensatz zwischen der klassischen Physik und der Quantenphysik. Es handelt sich lediglich um eine Differenzierung nach den unterschiedlichen physikalischen Inhalten und den angemessenen mathematischen Methoden, die natürlich von der Wahl der Probleme abhängen.Die theoretische Physik stellt eine allgemein zugängliche Zusammenfassung des gesicherten Wissens der Physik dar, das zugleich das Fundament der exakten Wissenschaften ist.Die theoretische Physik ist damit das Mittel der Verständigung innerhalb der Kooperation, die notwendig ist zur Lösung der großen komplexen Aufgaben der Wissenschaft und Technik.

  7. Influence of dem in Watershed Management as Flood Zonation Mapping

    NASA Astrophysics Data System (ADS)

    Alrajhi, Muhamad; Khan, Mudasir; Afroz Khan, Mohammad; Alobeid, Abdalla

    2016-06-01

    Despite of valuable efforts from working groups and research organizations towards flood hazard reduction through its program, still minimal diminution from these hazards has been realized. This is mainly due to the fact that with rapid increase in population and urbanization coupled with climate change, flood hazards are becoming increasingly catastrophic. Therefore there is a need to understand and access flood hazards and develop means to deal with it through proper preparations, and preventive measures. To achieve this aim, Geographical Information System (GIS), geospatial and hydrological models were used as tools to tackle with influence of flash floods in the Kingdom of Saudi Arabia due to existence of large valleys (Wadis) which is a matter of great concern. In this research paper, Digital Elevation Models (DEMs) of different resolution (30m, 20m,10m and 5m) have been used, which have proven to be valuable tool for the topographic parameterization of hydrological models which are the basis for any flood modelling process. The DEM was used as input for performing spatial analysis and obtaining derivative products and delineate watershed characteristics of the study area using ArcGIS desktop and its Arc Hydro extension tools to check comparability of different elevation models for flood Zonation mapping. The derived drainage patterns have been overlaid over aerial imagery of study area, to check influence of greater amount of precipitation which can turn into massive destructions. The flow accumulation maps derived provide zones of highest accumulation and possible flow directions. This approach provide simplified means of predicting extent of inundation during flood events for emergency action especially for large areas because of large coverage area of the remotely sensed data.

  8. Evaluating Error of LIDAR Derived dem Interpolation for Vegetation Area

    NASA Astrophysics Data System (ADS)

    Ismail, Z.; Khanan, M. F. Abdul; Omar, F. Z.; Rahman, M. Z. Abdul; Mohd Salleh, M. R.

    2016-09-01

    Light Detection and Ranging or LiDAR data is a data source for deriving digital terrain model while Digital Elevation Model or DEM is usable within Geographical Information System or GIS. The aim of this study is to evaluate the accuracy of LiDAR derived DEM generated based on different interpolation methods and slope classes. Initially, the study area is divided into three slope classes: (a) slope class one (0° - 5°), (b) slope class two (6° - 10°) and (c) slope class three (11° - 15°). Secondly, each slope class is tested using three distinctive interpolation methods: (a) Kriging, (b) Inverse Distance Weighting (IDW) and (c) Spline. Next, accuracy assessment is done based on field survey tachymetry data. The finding reveals that the overall Root Mean Square Error or RMSE for Kriging provided the lowest value of 0.727 m for both 0.5 m and 1 m spatial resolutions of oil palm area, followed by Spline with values of 0.734 m for 0.5 m spatial resolution and 0.747 m for spatial resolution of 1 m. Concurrently, IDW provided the highest RMSE value of 0.784 m for both spatial resolutions of 0.5 and 1 m. For rubber area, Spline provided the lowest RMSE value of 0.746 m for 0.5 m spatial resolution and 0.760 m for 1 m spatial resolution. The highest value of RMSE for rubber area is IDW with the value of 1.061 m for both spatial resolutions. Finally, Kriging gave the RMSE value of 0.790m for both spatial resolutions.

  9. Digital elevation model (DEM) of Cascadia, latitude 39N-53N, longitude 116W-133W

    USGS Publications Warehouse

    Haugerud, Ralph A.

    1999-01-01

    This report contains a 250-meter digital elevation model (DEM) for Cascadia (latitude 39N - 53N, longitude 116W - 133W), a region that encompasses the Cascade volcanic arc, the Cascadia subduction zone, and the Juan de Fuca Ridge system. The DEM is distributed as file cascdem.tar.gz (39 MB; 78MB uncompressed).

  10. Icesat Validation of Tandem-X I-Dems Over the UK

    NASA Astrophysics Data System (ADS)

    Feng, L.; Muller, J.-P.

    2016-06-01

    From the latest TanDEM-X mission (bistatic X-Band interferometric SAR), globally consistent Digital Elevation Model (DEM) will be available from 2017, but their accuracy has not yet been fully characterised. This paper presents the methods and implementation of statistical procedures for the validation of the vertical accuracy of TanDEM-X iDEMs at grid-spacing of approximately 12.5 m, 30 m and 90 m based on processed ICESat data over the UK in order to assess their potential extrapolation across the globe. The accuracy of the TanDEM-X iDEM in UK was obtained as follows: against ICESat GLA14 elevation data, TanDEM-X iDEM has -0.028±3.654 m over England and Wales and 0.316 ± 5.286 m over Scotland for 12 m, -0.073 ± 6.575 m for 30 m, and 0.0225 ± 9.251 m at 90 m. Moreover, 90 % of all results at the three resolutions of TanDEM-X iDEM data (with a linear error at 90 % confidence level) are below 16.2 m. These validation results also indicate that derivative topographic parameters (slope, aspect and relief) have a strong effect on the vertical accuracy of the TanDEM-X iDEMs. In high-relief and large slope terrain, large errors and data voids are frequent, and their location is strongly influenced by topography, whilst in the low- to medium-relief and low slope sites, errors are smaller. ICESat derived elevations are heavily influenced by surface slope within the 70 m footprint as well as there being slope dependent errors in the TanDEM-X iDEMs.

  11. FORS am Very Large Telescope der Europäischen Südsternwarte

    NASA Astrophysics Data System (ADS)

    1998-09-01

    Erstes wissenschaftliches Beobachtungsinstrument liefert eindrucksvolle Bilder Entsprechend dem straffen Zeitplan wird das ESO Very Large Teleskop Projekt (VLT-Projekt) auf dem Cerro Paranal in Nord-Chile verwirklicht: die volle Betriebsbereitschaft des ersten der vier 8,2m-Einzelteleskope wird Anfang des nächsten Jahres erreicht sein. Am 15. September 1998 wurde ein weiterer wichtiger Meilenstein erfolgreich, rechtzeitig und innerhalb des Kostenplans erreicht. Nur wenige Tage nach seiner Montage am ersten 8,2m-Einzelteleskop des VLT (UT1) konnte FORS1 ( FO cal R educer and S pectrograph) als erstes einer Gruppe leistungsfähiger und komplexer wissenschaftlicher Instrumente seine Beobachtungstätigkeit beginnen. Von Anfang an konnte es eine Reihe exzellenter astronomischer Bilder aufnehmen. Dieses bedeutende Ereignis eröffnet eine Fülle neuer Möglichkeiten für die europäische Astronomie. FORS - ein Höhepunkt an Komplexität FORS1 und das zukünftige Zwillingsinstrument (FORS2) sind das Ergebnis einer der eingehendsten und fortschrittlichsten technologischen Studien, die je für ein Instrument der bodengebundenen Astronomie durchgeführt wurden. Dieses einzigartige Instrument ist nun im Cassegrain-Fokus installiert und verschwindet beinahe, trotz seiner Dimensionen von 3 x 1.5m (Gewicht 2.3t), unterhalb des riesigen 53 m 2 großen Zerodurspiegels. Um die große Spiegelfläche und die hervorragende Bildqualität von UT1 optimal auszunützen, wurde FORS speziell so konstruiert, daß es die lichtschwächsten und entferntesten Objekte im Weltall untersuchen kann. Bald wird dieses komplexe VLT-Instrument den europäischen Astronomen erlauben, die derzeitigen Beobachtungshorizonte entscheidend zu erweitern. Die beiden FORS-Instrumente sind Vielzweck-Beobachtungsinstrumente, die in mehreren unterschiedlichen Beobachtungsarten eingesetzt werden können. Beispielsweise können Bilder mit zwei verschiedenen Abbildungsmaßstäben (Vergrößerungen) sowie Spektren mit

  12. Profiles of IgE Sensitization to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20 in Korean House Dust Mite Allergy Patients

    PubMed Central

    Jeong, Kyoung Yong; Lee, June Yong; Son, Mina; Yi, Myung-hee; Yong, Tai-Soon; Shin, Jung U; Lee, Kwang Hoon; Kim, Yoon-Ju; Park, Kyung Hee; Park, Hye Jung; Lee, Jae-Hyun

    2015-01-01

    Purpose Measurement of IgE specific to purified house dust mite (HDM) allergens may improve allergy diagnosis. This study aimed to investigate the sensitization profiles of Korean HDM allergic subjects suffering from respiratory allergy and atopic dermatitis (AD) to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20. Methods Recombinant HDM allergens were produced in Pichia pastoris (Der f 1) or Escherichia coli (5 allergens). IgE reactivity to the individual recombinant allergens and total extract of mite was assessed by ELISA. Results Der f 1 was recognized by 79.1%, Der f 2 by 79.1%, Der f 6 by 9.3%, Der f 8 by 6.2%, Der f 10 by 6.2%, and Der f 20 by 6.6% of the patients' sera tested, while the prevalence of IgE reactivity to total mite extract was 94.7%. Combination of Der f 1 and Der f 2 had a sensitivity of 87.6%. Specific IgE to Der f 2 alone was detected from 89.4% of HDM-sensitized respiratory allergy subjects and 92.3% to the combination of the 2 major allergens Der f 1 and Der f 2. However, sera from fewer patients with AD, namely 72.4% and 71.0%, recognized Der f 1 and Der f 2, respectively. The combination of 2 major allergens allowed diagnosis of 84.5% of the AD patients. No correlation between sensitization to specific allergens and HDM allergy entity was found. Conclusions Der f 2 was the most frequently sensitized allergen among the HDM-sensitized respiratory and AD patients in Korea, and the combination of the group 1 and 2 major allergens increased the diagnostic sensitivity. Minor allergens did not significantly improve diagnostic sensitivity. However, further studies are needed to analyze the relationship between sensitization to other HDM allergens and the disease entity of the HDM allergy. PMID:25749773

  13. Strategische Planung in der Medizintechnik

    NASA Astrophysics Data System (ADS)

    Leewe, Jörn

    Für den Aufstieg und den Niedergang der Unternehmen spielt die Über- oder Unterlegenheit der Technologie eine zentrale Rolle. Mindestens im gleichen Maße ist jedoch auch ein umsichtiges Management und eine sorgfältige strategische Planung für den Erfolg verantwortlich. Nur ein profitables Unternehmen, welches nachhaltige Gewinne erzielt, ist in der Lage, eine Spitzenforschung aus eigener Kraft zu finanzieren. Dies klingt zunächst trivial. In der langjährigen Consulting-Praxis sind wir jedoch diversen Unternehmen begegnet, die diese Maxime vernachlässigt haben und aufgrund mangelhafter Planungen eine Insolvenz dann nicht mehr abwenden konnten. Damit es erst gar nicht dazu kommt, sollten unterschiedliche Handlungsalternativen im voraus entwickelt und bewertet werden. Die Strategie, also das systematische Aufbauen von Wettbewerbsvorteilen, sollte regelmässig überprüft werden und eine finanzielle Entwicklung des Produktes oder des Unternehmens sollte regelmäßig antizipiert und simuliert werden. Dieser Beitrag soll Einblicke in die strategische Planung erlauben, erhebt allerdings aufgrund der Komplexität des Themas keinen Anspruch auf Vollständigkeit.

  14. Evaluating SRTM and ASTER DEM accuracy for the broader area of Sparti, Greece

    NASA Astrophysics Data System (ADS)

    Nikolakopoulos, Konstantinos G.; Tsombos, Panagiotis I.; Zervakou, Alexandra

    2007-10-01

    One of the major projects of the Institute of Geology & Mineral Exploration (IGME) is called "Urban Geology". In the frame of that project there is need for a high accuracy DEM covering the whole country. The DEM should be used for the orthorectification of high resolution images and other applications such as slope map creation, environmental planning et.c. ASTER and SRTM are two possible sources for DEM covering the whole country. According to the specifications the ASTER vertical accuracy of DEM is about 20m with 95% confidence while the horizontal geolocation accuracy appears to be better than 50 m. More recent studies have shown that the use of GCP's resulted in a plannimetric accuracy of 15 m and in a near pixel size vertical accuracy. The Shuttle Radar Topography Mission (SRTM), used an Interferometric Synthetic Aperture Radar (IFSAR) instrument to produce a near-global digital elevation map of the earth's land surface with 16 m absolute vertical height accuracy at 30 meter postings. An SRTM 3-arc-second product (90m resolution) is available for the entire world. In this paper we examine the accuracy of SRTM and ASTER DEMs in comparison to the accuracy of the 1/5.000 topographic maps. The area of study is the broader area of Sparti, Greece. After a first control for random or systematic errors a statistical analysis was done. A DEM derived from digitized contours of the 1:5.000 topographic maps was created and compared with ASTER and SRTM derived DEMs. Fifty-five points of known elevation have been used to estimate the accuracy of these three DEMs. Slope and aspect maps were created and compared. The elevation difference between the three DEMs was calculated. 2D RMSE, correlation and the percentile value were also computed. The three DEMs were used for the orthorectification of very high resolution data and the final orthophotos were compared.

  15. Open-Source Digital Elevation Model (DEMs) Evaluation with GPS and LiDAR Data

    NASA Astrophysics Data System (ADS)

    Khalid, N. F.; Din, A. H. M.; Omar, K. M.; Khanan, M. F. A.; Omar, A. H.; Hamid, A. I. A.; Pa'suya, M. F.

    2016-09-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer-Global Digital Elevation Model (ASTER GDEM), Shuttle Radar Topography Mission (SRTM), and Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) are freely available Digital Elevation Model (DEM) datasets for environmental modeling and studies. The quality of spatial resolution and vertical accuracy of the DEM data source has a great influence particularly on the accuracy specifically for inundation mapping. Most of the coastal inundation risk studies used the publicly available DEM to estimated the coastal inundation and associated damaged especially to human population based on the increment of sea level. In this study, the comparison between ground truth data from Global Positioning System (GPS) observation and DEM is done to evaluate the accuracy of each DEM. The vertical accuracy of SRTM shows better result against ASTER and GMTED10 with an RMSE of 6.054 m. On top of the accuracy, the correlation of DEM is identified with the high determination of coefficient of 0.912 for SRTM. For coastal zone area, DEMs based on airborne light detection and ranging (LiDAR) dataset was used as ground truth data relating to terrain height. In this case, the LiDAR DEM is compared against the new SRTM DEM after applying the scale factor. From the findings, the accuracy of the new DEM model from SRTM can be improved by applying scale factor. The result clearly shows that the value of RMSE exhibit slightly different when it reached 0.503 m. Hence, this new model is the most suitable and meets the accuracy requirement for coastal inundation risk assessment using open source data. The suitability of these datasets for further analysis on coastal management studies is vital to assess the potentially vulnerable areas caused by coastal inundation.

  16. Mathematik im Kontext Bericht aus dem Projekt "Fächerkonzepte und Bildung"

    NASA Astrophysics Data System (ADS)

    Vohns, Andreas

    "Mathematik - das hab ich nie verstanden". Wenn man diese Aussage im Alltag hört, dann ist damit in der Regel mehr gemeint als der bloße Hinweis auf gewisse individuelle Wissenslücken. Es geht auch (vielleicht sogar vorrangig) um eine mangelnde Vorstellung davon, worin eigentlich die Bedeutung dessen liegt, was man unter der Überschrift "Mathematik" in der Schule gelernt hat.

  17. Twisted Van der Waals Systems

    NASA Astrophysics Data System (ADS)

    Gani, Satrio; Rossi, Enrico

    Van der Waals systems formed by two-dimensional (2D) crystals and nanostructures possess electronic properties that make them extremely interesting for basic science and for possible technological applications. By tuning the relative angle (the twist angle) between the layers, or nanostructures, forming the Van der Waals systems experimentalists have been able to control the stacking configuration of such systems. We study the dependence on the twist angle of the electronic properties of two classes of Van der Waals systems: double layers formed by two, one-atom thick, layers of a metal dichalcogenide such as molybdenum disulfide (MoS2), and graphene nanoribbons on a hexagonal boron nitride substrate. We present results that show how, for both classes of systems, the electronic properties can be strongly tuned via the twist angle. Work supported by ACS-PRF-53581-DNI5 and NSF-DMR-1455233.

  18. Historisches Rätsel Der rastlose Amerikaner

    NASA Astrophysics Data System (ADS)

    Loos, Andreas

    2004-09-01

    In der Schule, die er mit acht Jahren zum ersten Mal von innen sah, hielt man ihn nicht für allzu helle - schließlich hinkte der Kleine oft hinter der Klasse her. Und es hat etwas Tragisches, wenn der wohl berühmteste Erfinder aller Zeiten und Halter von 2000 Patenten im Alter über seinen Vater sagt: Er dachte, ich sei dumm. Und ich meinte schon fast selbst, ich sei ein Dummkopf.

  19. Impacts of DEM uncertainties on critical source areas identification for non-point source pollution control based on SWAT model

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Dong, Guangxia; Wang, Qingrui; Liu, Lumeng; Yu, Wenwen; Men, Cong; Liu, Ruimin

    2016-09-01

    The impacts of different digital elevation model (DEM) resolutions, sources and resampling techniques on nutrient simulations using the Soil and Water Assessment Tool (SWAT) model have not been well studied. The objective of this study was to evaluate the sensitivities of DEM resolutions (from 30 m to 1000 m), sources (ASTER GDEM2, SRTM and Topo-DEM) and resampling techniques (nearest neighbor, bilinear interpolation, cubic convolution and majority) to identification of non-point source (NPS) critical source area (CSA) based on nutrient loads using the SWAT model. The Xiangxi River, one of the main tributaries of Three Gorges Reservoir in China, was selected as the study area. The following findings were obtained: (1) Elevation and slope extracted from the DEMs were more sensitive to DEM resolution changes. Compared with the results of the 30 m DEM, 1000 m DEM underestimated the elevation and slope by 104 m and 41.57°, respectively; (2) The numbers of subwatersheds and hydrologic response units (HRUs) were considerably influenced by DEM resolutions, but the total nitrogen (TN) and total phosphorus (TP) loads of each subwatershed showed higher correlations with different DEM sources; (3) DEM resolutions and sources had larger effects on CSAs identifications, while TN and TP CSAs showed different response to DEM uncertainties. TN CSAs were more sensitive to resolution changes, exhibiting six distribution patterns at all DEM resolutions. TP CSAs were sensitive to source and resampling technique changes, exhibiting three distribution patterns for DEM sources and two distribution patterns for DEM resampling techniques. DEM resolutions and sources are the two most sensitive SWAT model DEM parameters that must be considered when nutrient CSAs are identified.

  20. Der Begriff der Verständlichkeit in der modernen Physik (1948).

    PubMed

    Feyerabend, Paul K

    2016-06-01

    This is a critical transcription of Paul Feyerabend's earliest extant essay "Der Begriff der Verständlichkeit in der modernen Physik" (1948) recovered from the European Forum Alpbach archives. In it, Feyerabend defends positivism as a progressive framework for scientific research in certain stages of scientific development. He argues that in physics visualizability (Anschaulichkeit) and intelligibility (Verständlichkeit) are time-conditioned concepts: what is deemed visualizable in the development of physical theories is relative to a specific historical context and changes over time. He concludes that from time to time the abandonment of visualizability is crucial for progress in physics, as it is conducive to major theory change, illustrating the point on the basis of advances in atomic theory. PMID:27269264

  1. Comparative Influence of Terrain Slope and Canopy Closure on Lidar DEM Accuracy

    NASA Astrophysics Data System (ADS)

    Tinkham, W.; Smith, A. M.; Hudak, A. T.; Gessler, P.; Swanson, M.

    2009-12-01

    The use of Lidar (Light Detection and Ranging) technology is becoming one of the most effective and reliable means of collecting a variety of terrain and vegetation data. Most Lidar based estimates come from the creation of digital elevation models (DEM). As a result of the DEM’s importance in using Lidar data as a management tool, it is necessary to understand the variables that influence the DEM accuracy. Two of these variables, terrain slope and percent canopy closure, were investigated in a mixed conifer forest and woodland area in central Idaho. Following the creation of a DEM from the last return Lidar points, a series of 54 fixed radius plots were stratified by 3 slope classes from 0% to 45% and 3 canopy closures classes from 0% to 95% and surveyed using a laser total station and differential GPS for DEM accuracy analysis. Within each tenth acre plot a grid consisting of 80 ground points was collected along with a point for each tree and each 1,000 hour fuel, further data was collected to classify the canopy and the fuel loading. Each plot was processed to create a DEM for comparison to the Lidar derived DEM. These results will have implications in the development and use of high-resolution DEM models derived from Lidar data for natural resource managers.

  2. Improving Cartosat-1 DEM accuracy using synthetic stereo pair and triplet

    NASA Astrophysics Data System (ADS)

    Giribabu, D.; Srinivasa Rao, S.; Krishna Murthy, Y. V. N.

    2013-03-01

    Cartosat-1 is the first Indian Remote Sensing Satellite capable of providing along-track stereo images. Cartosat-1 provides forward stereo images with look angles +26° and -5° with respect to nadir for generating Digital Elevation Models (DEMs), Orthoimages and value added products for various applications. A pitch bias of -21° to the satellite resulted in giving reverse tilt mode stereo pair with look angles of +5° and -26° with respect to nadir. This paper compares DEMs generated using forward, reverse and other possible synthetic stereo pairs for two different types of topographies. Stereo triplet was used to generate DEM for Himalayan mountain topography to overcome the problem of occlusions. For flat to undulating topography it was shown that using Cartosat-1 synthetic stereo pair with look angles of -26° and +26° will produce improved version of DEM. Planimetric and height accuracy (Root Mean Square Error (RMSE)) of less than 2.5 m and 2.95 m respectively were obtained and qualitative analysis shows finer details in comparison with other DEMs. For rugged terrain and steep slopes of Himalayan mountain topography simple stereo pairs may not provide reliable accuracies in DEMs due to occlusions and shadows. Stereo triplet from Cartosat-1 was used to generate DEM for mountainous topography. This DEM shows better reconstruction of elevation model even at occluded region when compared with simple stereo pair based DEM. Planimetric and height accuracy (RMSE) of nearly 3 m were obtained and qualitative analysis shows reduction of outliers at occluded region.

  3. Assessment of Uncertainty Propagation from DEM's on Small Scale Typologically-Differentiated Landslide Susceptibility in Romania

    NASA Astrophysics Data System (ADS)

    Cosmin Sandric, Ionut; Chitu, Zenaida; Jurchescu, Marta; Malet, Jean-Philippe; Ciprian Margarint, Mihai; Micu, Mihai

    2015-04-01

    An increasing number of free and open access global digital elevation models has become available in the past 15 years and these DEMs have been widely used for the assessment of landslide susceptibility at medium and small scales. Even though the global vertical and horizontal accuracies of each DEM are known, what it is still unknown is the uncertainty that propagates from the first and second derivatives of DEMs, like slope gradient, into the final landslide susceptibility map For the present study we focused on the assessment of the uncertainty propagation from the following digital elevation models: SRTM 90m spatial resolution, ASTERDEM 30m spatial resolution, EUDEM 30m spatial resolution and the latest release SRTM 30m spatial resolution. From each DEM dataset the slope gradient was generated and used in the landslide susceptibility analysis. A restricted number of spatial predictors are used for landslide susceptibility assessment, represented by lithology, land-cover and slope, were the slope is the only predictor that changes with each DEM. The study makes use of the first national landslide inventory (Micu et al, 2014) obtained from compiling literature data, personal or institutional landslide inventories. The landslide inventory contains more than 27,900 cases classified in three main categories: slides flows and falls The results present landslide susceptibility maps obtained from each DEM and from the combinations of DEM datasets. Maps with uncertainty propagation at country level and differentiated by topographic regions from Romania and by landslide typology (slides, flows and falls) are obtained for each DEM dataset and for the combinations of these. An objective evaluation of each DEM dataset and a final map of landslide susceptibility and the associated uncertainty are provided

  4. Incorporating the effect of DEM resolution and accuracy for improved flood inundation mapping

    NASA Astrophysics Data System (ADS)

    Saksena, Siddharth; Merwade, Venkatesh

    2015-11-01

    Topography plays a major role in determining the accuracy of flood inundation areas. However, many areas in the United States and around the world do not have access to high quality topographic data in the form of Digital Elevation Models (DEM). For such areas, an improved understanding of the effects of DEM properties such as horizontal resolution and vertical accuracy on flood inundation maps may eventually lead to improved flood inundation modeling and mapping. This study attempts to relate the errors arising from DEM properties such as spatial resolution and vertical accuracy to flood inundation maps, and then use this relationship to create improved flood inundation maps from coarser resolution DEMs with low accuracy. The results from the five stream reaches used in this study show that water surface elevations (WSE) along the stream and the flood inundation area have a linear relationship with both DEM resolution and accuracy. This linear relationship is then used to extrapolate the water surface elevations from coarser resolution DEMs to get water surface elevations corresponding to a finer resolution DEM. Application of this approach show that improved results can be obtained from flood modeling by using coarser and less accurate DEMs, including public domain datasets such as the National Elevation Dataset and Shuttle Radar Topography Mission (SRTM) DEMs. The improvement in the WSE and its application to obtain better flood inundation maps is dependent on the study reach characteristics such as land use, valley shape, reach length and width. Application of the approach presented in this study on more reaches may lead to development of guidelines for flood inundation mapping using coarser resolution and less accurate topographic datasets.

  5. Ancillary Services Provided from DER

    SciTech Connect

    Campbell, J.B.

    2005-12-21

    Distributed energy resources (DER) are quickly making their way to industry primarily as backup generation. They are effective at starting and then producing full-load power within a few seconds. The distribution system is aging and transmission system development has not kept up with the growth in load and generation. The nation's transmission system is stressed with heavy power flows over long distances, and many areas are experiencing problems in providing the power quality needed to satisfy customers. Thus, a new market for DER is beginning to emerge. DER can alleviate the burden on the distribution system by providing ancillary services while providing a cost adjustment for the DER owner. This report describes 10 types of ancillary services that distributed generation (DG) can provide to the distribution system. Of these 10 services the feasibility, control strategy, effectiveness, and cost benefits are all analyzed as in the context of a future utility-power market. In this market, services will be provided at a local level that will benefit the customer, the distribution utility, and the transmission company.

  6. Evaluation of DEM generation accuracy from UAS imagery

    NASA Astrophysics Data System (ADS)

    Santise, M.; Fornari, M.; Forlani, G.; Roncella, R.

    2014-06-01

    The growing use of UAS platform for aerial photogrammetry comes with a new family of Computer Vision highly automated processing software expressly built to manage the peculiar characteristics of these blocks of images. It is of interest to photogrammetrist and professionals, therefore, to find out whether the image orientation and DSM generation methods implemented in such software are reliable and the DSMs and orthophotos are accurate. On a more general basis, it is interesting to figure out whether it is still worth applying the standard rules of aerial photogrammetry to the case of drones, achieving the same inner strength and the same accuracies as well. With such goals in mind, a test area has been set up at the University Campus in Parma. A large number of ground points has been measured on natural as well as signalized points, to provide a comprehensive test field, to check the accuracy performance of different UAS systems. In the test area, points both at ground-level and features on the buildings roofs were measured, in order to obtain a distributed support also altimetrically. Control points were set on different types of surfaces (buildings, asphalt, target, fields of grass and bumps); break lines, were also employed. The paper presents the results of a comparison between two different surveys for DEM (Digital Elevation Model) generation, performed at 70 m and 140 m flying height, using a Falcon 8 UAS.

  7. Investigation of the Critical State in Soil Mechanics Using DEM

    SciTech Connect

    Pena, Andres A.; Garcia-Rojo, Ramon; Alonso-Marroquin, Fernando; Herrmann, Hans J.

    2009-06-18

    The existence and uniqueness of the so-called critical state in soil mechanics is validated in our DEM simulations of irregular polygonal particles. For different particle shape characteristics, the critical state is independent of the initial stress and density conditions. We retain low stress levels, since we do not take into account the crushing of particles. In biaxial test simulations isotropic particles evolve toward a limiting state in which the system reaches a critical void ratio and deforms with constant volume, deviatoric stress, fabric anisotropy, and mechanical coordination number. The last one has been found to be the first variable to attain a critical value making possible for the rest of micro-and-macro-mechanical variables the convergence to the critical state. In periodic shear cell tests, for large shear deformations samples with anisotropic particles reach at the macro-mechanical level the same critical value for both shear force and void ratio. At the micro-mechanical level the components of the stress tensor, the fabric tensor and the inertia tensor of the particles also reach the same stationary state. By varying the aspect ratio of the particles we stated the strong influence of particle shape anisotropy on the parameters that the granular packing attained at the critical state.

  8. SRTM DEM levels over papyrus swamp vegetation - a correction approach

    NASA Astrophysics Data System (ADS)

    Petersen, G.; Lebed, I.; Fohrer, N.

    2009-08-01

    The SRTM DEM, a digital elevation model based on the Shuttle Radar Topography Mission of February 2000 is a source of elevation data with nearly worldwide coverage. It has proven its usefulness in various regions but problems persist for densely vegetated areas where, caused by the organic matter and water content of the vegetation, the radar signal is reflected at some level between the vegetation canopy and the ground level. This level varies with different types and densities of vegetation cover and has so far not been assessed for papyrus areas. The paper describes the approach and establishment of a correction factor for a pilot area in the Sudd swamps of southern Sudan based on comparison of SRTM reference levels and ground control points collected during field surveys between 2004 and 2006. Results show a correction factor between the sensed and the real surface of 4.66 m and a average penetration depth of the radar signal into the dense papyrus vegetation of 0.34 m.

  9. Penetration strength of coarse granular materials from DEM simulations

    NASA Astrophysics Data System (ADS)

    Quezada, Juan Carlos; Saussine, Gilles; Breul, Pierre; Radjai, Farhang

    2013-06-01

    Field tests are widely used for soil characterization in geotechnical applications in spite of implementation difficulties. The light penetrometer test is a well-known testing tool for fine soils, but the physical interpretation of the output data in the case of coarse granular materials is far less evident. In fact, the data are considerably more sensitive to various parameters such as fabric structure, particles shape or the applied impact energy. In order to achieve a better understanding of the underlying phenomena, we performed a numerical study by means contact dynamics DEM simulations. We consider the penetration of a moving tip into a sample composed of irregular grain shapes and we analyze the influence of the driving velocity and applied energy on the penetration strength. We find that the latter grows with both the penetration rate and energy. Force fluctuations on the tip involve a jamming-unjamming process. The typology of contact network and inter-granular friction play a major role in the fluctuations and measured values of the cone penetration strength.

  10. DEM Simulation of Particle Clogging in Fiber Filtration

    NASA Astrophysics Data System (ADS)

    Tao, Ran; Yang, Mengmeng; Li, Shuiqing

    2015-11-01

    The formation of porous particle deposits plays a crucial role in determining the efficiency of filtration process. In this work, an adhesive discrete element method (DEM), in combination with CFD, is developed to dynamically describe these porous deposit structures and the changed flow field between two parallel fibers under the periodic boundary conditions. For the first time, it is clarified that the structures of clogged particles are dependent on both the adhesion parameter (defined as the ratio of interparticle adhesion to particle inertia) and the Stokes number (as an index of impaction efficiency). The relationship between the pressure-drop gradient and the coordination number along the filtration time is explored, which can be used to quantitatively classify the different filtration regimes, i.e., clean filter stage, clogging stage and cake filtration stage. Finally, we investigate the influence of the fiber separation distance on the particle clogging behavior, which affects the collecting efficiency of the fibers significantly. The results suggest that changing the arrangement of fibers can improve the filter performance. This work has been funded by the National Key Basic Research and Development Program (2013CB228506).

  11. SPH-DEM simulations of grain dispersion by liquid injection

    NASA Astrophysics Data System (ADS)

    Robinson, Martin; Luding, Stefan; Ramaioli, Marco

    2013-06-01

    We study the dispersion of an initially packed, static granular bed by the injection of a liquid jet. This is a relevant system for many industrial applications, including paint dispersion or food powder dissolution. Both decompaction and dispersion of the powder are not fully understood, leading to inefficiencies in these processes. Here we consider a model problem where the liquid jet is injected below a granular bed contained in a cylindrical cell. Two different initial conditions are considered: a two-phase case where the bed is initially fully immersed in the liquid and a three-phase case where the bed and cell are completely dry preceding the injection of the liquid. The focus of this contribution is the simulation of these model problems using a two-way coupled SPH-DEM granularliquid method [M. Robinson, M. Ramaioli, and S. Luding, submitted (2013) and http://arxiv.org/abs/1301.0752 (2013)]. This is a purely particle-based method without any prescribed mesh, well suited for this and other problems involving a free (liquidgas) surface and a partly immersed particle phase. Our simulations show the effect of process parameters such as injection flow rate and injection diameter on the dispersion pattern, namely whether the granular bed is impregnated bottom-up or a jet is formed and compare well with experiments.

  12. Scenario-Based Validation of Moderate Resolution DEMs Freely Available for Complex Himalayan Terrain

    NASA Astrophysics Data System (ADS)

    Singh, Mritunjay Kumar; Gupta, R. D.; Snehmani; Bhardwaj, Anshuman; Ganju, Ashwagosha

    2016-02-01

    Accuracy of the Digital Elevation Model (DEM) affects the accuracy of various geoscience and environmental modelling results. This study evaluates accuracies of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global DEM Version-2 (GDEM V2), the Shuttle Radar Topography Mission (SRTM) X-band DEM and the NRSC Cartosat-1 DEM V1 (CartoDEM). A high resolution (1 m) photogrammetric DEM (ADS80 DEM), having a high absolute accuracy [1.60 m linear error at 90 % confidence (LE90)], resampled at 30 m cell size was used as reference. The overall root mean square error (RMSE) in vertical accuracy was 23, 73, and 166 m and the LE90 was 36, 75, and 256 m for ASTER GDEM V2, SRTM X-band DEM and CartoDEM, respectively. A detailed error analysis was performed for individual as well as combinations of different classes of aspect, slope, land-cover and elevation zones for the study area. For the ASTER GDEM V2, forest areas with North facing slopes (0°-5°) in the 4th elevation zone (3773-4369 m) showed minimum LE90 of 0.99 m, and barren with East facing slopes (>60°) falling under the 2nd elevation zone (2581-3177 m) showed maximum LE90 of 166 m. For the SRTM DEM, pixels with South-East facing slopes of 0°-5° in the 4th elevation zone covered with forest showed least LE90 of 0.33 m and maximum LE90 of 521 m was observed in the barren area with North-East facing slope (>60°) in the 4th elevation zone. In case of the CartoDEM, the snow pixels in the 2nd elevation zone with South-East facing slopes of 5°-15° showed least LE90 of 0.71 m and maximum LE90 of 1266 m was observed for the snow pixels in the 3rd elevation zone (3177-3773 m) within the South facing slope of 45°-60°. These results can be highly useful for the researchers using DEM products in various modelling exercises.

  13. TecDEM: A MATLAB based toolbox for tectonic geomorphology, Part 1: Drainage network preprocessing and stream profile analysis

    NASA Astrophysics Data System (ADS)

    Shahzad, Faisal; Gloaguen, Richard

    2011-02-01

    We present TecDEM, a software shell implemented in MATLAB that applies tectonic geomorphologic tasks to digital elevation models (DEMs). The first part of this paper series describes drainage partitioning schemes and stream profile analysis. The graphical user interface of TecDEM provides several options: determining flow directions, stream vectorization, watershed delineation, Strahler order labeling, stream profile generation, knickpoints selection, Concavity, Steepness and Hack indices calculations. The knickpoints along selected streams as well as stream profile analysis, and Hack index per stream profile are computed using a semi-automatic method. TecDEM was used to extract and investigate the stream profiles in the Kaghan Valley (Northern Pakistan). Our interpretations of the TecDEM results correlate well with previous tectonic evolution models for this region. TecDEM is designed to assist geoscientists in applying complex tectonic geomorphology tasks to global DEM data.

  14. What is the effect of LiDAR-derived DEM resolution on large-scale watershed model results?

    SciTech Connect

    Ping Yang; Daniel B. Ames; Andre Fonseca; Danny Anderson; Rupesh Shrestha; Nancy F. Glenn; Yang Cao

    2014-08-01

    This paper examines the effect of raster cell size on hydrographic feature extraction and hydrological modeling using LiDAR derived DEMs. LiDAR datasets for three experimental watersheds were converted to DEMs at various cell sizes. Watershed boundaries and stream networks were delineated from each DEM and were compared to reference data. Hydrological simulations were conducted and the outputs were compared. Smaller cell size DEMs consistently resulted in less difference between DEM-delineated features and reference data. However, minor differences been found between streamflow simulations resulted for a lumped watershed model run at daily simulations aggregated at an annual average. These findings indicate that while higher resolution DEM grids may result in more accurate representation of terrain characteristics, such variations do not necessarily improve watershed scale simulation modeling. Hence the additional expense of generating high resolution DEM's for the purpose of watershed modeling at daily or longer time steps may not be warranted.

  15. Automated sinkhole detection using a DEM subsetting technique and fill tools at Mammoth Cave National Park

    NASA Astrophysics Data System (ADS)

    Wall, J.; Bohnenstiehl, D. R.; Levine, N. S.

    2013-12-01

    An automated workflow for sinkhole detection is developed using Light Detection and Ranging (Lidar) data from Mammoth Cave National Park (MACA). While the park is known to sit within a karst formation, the generally dense canopy cover and the size of the park (~53,000 acres) creates issues for sinkhole inventorying. Lidar provides a useful remote sensing technology for peering beneath the canopy in hard to reach areas of the park. In order to detect sinkholes, a subsetting technique is used to interpolate a Digital Elevation Model (DEM) thereby reducing edge effects. For each subset, standard GIS fill tools are used to fill depressions within the DEM. The initial DEM is then subtracted from the filled DEM resulting in detected depressions or sinkholes. Resulting depressions are then described in terms of size and geospatial trend.

  16. Verbesserung der Prozessbedingungen beim Einlippentiefbohren durch unterschiedliche Formen der Vorschubmodulation

    NASA Astrophysics Data System (ADS)

    Eisseler, Rocco

    Das Tiefbohren mit Einlippenwerkzeugen ist bei vielen Anwendungen das Verfahren der ersten Wahl, vor allem wenn kleine und kleinste Bohrungsdurchmesser, ein sehr großes Verhältnis zwischen Bohrtiefe und Durchmesser (l/D) und eine hohe Bearbeitungsqualität gefordert werden. Der erreichbare Durchmesserbereich des Verfahrens liegt zwischen D = 0,5 mm und 40 mm, wobei die möglichen Bohrtiefen von l = 3 x D bis 250 x D reichen. Diese Werte beziehen sich auf das Vollbohren, beim Aufbohren können noch größere Durchmesser erreicht werden [1]. Die erreichbare Oberflächenqualität ist so hoch, dass in den meisten Fällen auf eine nachfolgende Feinbearbeitung verzichtet werden kann.

  17. Glacier Volume Change Estimation Using Time Series of Improved Aster Dems

    NASA Astrophysics Data System (ADS)

    Girod, Luc; Nuth, Christopher; Kääb, Andreas

    2016-06-01

    Volume change data is critical to the understanding of glacier response to climate change. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system embarked on the Terra (EOS AM-1) satellite has been a unique source of systematic stereoscopic images covering the whole globe at 15m resolution and at a consistent quality for over 15 years. While satellite stereo sensors with significantly improved radiometric and spatial resolution are available to date, the potential of ASTER data lies in its long consistent time series that is unrivaled, though not fully exploited for change analysis due to lack of data accuracy and precision. Here, we developed an improved method for ASTER DEM generation and implemented it in the open source photogrammetric library and software suite MicMac. The method relies on the computation of a rational polynomial coefficients (RPC) model and the detection and correction of cross-track sensor jitter in order to compute DEMs. ASTER data are strongly affected by attitude jitter, mainly of approximately 4 km and 30 km wavelength, and improving the generation of ASTER DEMs requires removal of this effect. Our sensor modeling does not require ground control points and allows thus potentially for the automatic processing of large data volumes. As a proof of concept, we chose a set of glaciers with reference DEMs available to assess the quality of our measurements. We use time series of ASTER scenes from which we extracted DEMs with a ground sampling distance of 15m. Our method directly measures and accounts for the cross-track component of jitter so that the resulting DEMs are not contaminated by this process. Since the along-track component of jitter has the same direction as the stereo parallaxes, the two cannot be separated and the elevations extracted are thus contaminated by along-track jitter. Initial tests reveal no clear relation between the cross-track and along-track components so that the latter seems not to be

  18. Hydrologic validation of a structure-from-motion DEM derived from low-altitude UAV imagery

    NASA Astrophysics Data System (ADS)

    Steiner, Florian; Marzolff, Irene; d'Oleire-Oltmanns, Sebastian

    2015-04-01

    The increasing ease of use of current Unmanned Aerial Vehicles (UAVs) and 3D image processing software has spurred the number of applications relying on high-resolution topographic datasets. Of particular significance in this field is "structure from motion" (SfM), a photogrammetric technique used to generate low-cost digital elevation models (DEMs) for erosion budgeting, measuring of glaciers/lava-flows, archaeological applications and others. It was originally designed to generate 3D-models of buildings, based on unordered collections of images and has become increasingly common in geoscience applications during the last few years. Several studies on the accuracy of this technique already exist, in which the SfM data is mostly compared with Lidar-generated terrain data. The results are mainly positive, indicating that the technique is suitable for such applications. This work aims at validating very high resolution SfM DEMs with a different approach: Not the original elevation data is validated, but data on terrain-related hydrological and geomorphometric parameters derived from the DEM. The study site chosen for this analysis is an abandoned agricultural field near the city of Taroudant, in the semi-arid southern part of Morocco. The site is characterized by aggressive rill and gully erosion and is - apart from sparsely scattered shrub cover - mainly featureless. An area of 5.7 ha, equipped with 30 high-precision ground control points (GCPs), was covered with an unmanned aerial vehicle (UAV) in two different heights (85 and 170 m). A selection of 160 images was used to generate several high-resolution DEMs (2 and 5 cm resolution) of the area using the fully automated SfM software AGISOFT Photoscan. For comparison purposes, a conventional photogrammetry-based workflow using the Leica Photogrammetry Suite was used to generate a DEM with a resolution of 5 cm (LPS DEM). The evaluation is done by comparison of the SfM DEM with the derived orthoimages and the LPS DEM

  19. The topographic grain concept in DEM-based geomorphometric mapping

    NASA Astrophysics Data System (ADS)

    Józsa, Edina

    2016-04-01

    A common drawback of geomorphological analyses based on digital elevation datasets is the definition of search window size for the derivation of morphometric variables. The fixed-size neighbourhood determines the scale of the analysis and mapping, which can lead to the generalization of smaller surface details or the elimination of larger landform elements. The methods of DEM-based geomorphometric mapping are constantly developing into the direction of multi-scale landform delineation, but the optimal threshold for search window size is still a limiting factor. A possible way to determine the suitable value for the parameter is to consider the topographic grain principle (Wood, W. F. - Snell, J. B. 1960, Pike, R. J. et al. 1989). The calculation is implemented as a bash shell script for GRASS GIS to determine the optimal threshold for the r.geomorphon module. The approach relies on the potential of the topographic grain to detect the characteristic local ridgeline-to-channel spacing. By calculating the relative relief values with nested neighbourhood matrices it is possible to define a break-point where the increase rate of local relief encountered by the sample is significantly reducing. The geomorphons approach (Jasiewicz, J. - Stepinski, T. F. 2013) is a cell-based DEM classification method for the identification of landform elements at a broad range of scales by using line-of-sight technique. The landforms larger than the maximum lookup distance are broken down to smaller elements therefore the threshold needs to be set for a relatively large value. On the contrary, the computational requirements and the size of the study sites determine the upper limit for the value. Therefore the aim was to create a tool that would help to determine the optimal parameter for r.geomorphon tool. As a result it would be possible to produce more objective and consistent maps with achieving the full efficiency of this mapping technique. For the thorough analysis on the

  20. HELI-DEM portal for geo-processing services

    NASA Astrophysics Data System (ADS)

    Cannata, Massimiliano; Antonovic, Milan; Molinari, Monia

    2014-05-01

    HELI-DEM (Helvetia-Italy Digital Elevation Model) is a project developed in the framework of Italy/Switzerland Operational Programme for Trans-frontier Cooperation 2007-2013 whose major aim is to create a unified digital terrain model that includes the alpine and sub-alpine areas between Italy and Switzerland. The partners of the project are: Lombardy Region, Piedmont Region, Polytechnic of Milan, Polytechnic of Turin and Fondazione Politecnico from Italy; Institute of Earth Sciences (SUPSI) from Switzerland. The digital terrain model has been produced by integrating and validating the different elevation data available for the areas of interest, characterized by different reference frame, resolutions and accuracies: DHM at 25 m resolution from Swisstopo, DTM at 20 m resolution from Lombardy Region, DTM at 5 m resolution from Piedmont Region and DTM LiDAR PST-A at about 1 m resolution, that covers the main river bed areas and is produced by the Italian Ministry of the Environment. Further results of the project are: the generation of a unique Italian Swiss geoid with an accuracy of few centimeters (Gilardoni et al. 2012); the establishment of a GNSS permanent network, prototype of a transnational positioning service; the development of a geo-portal, entirely based on open source technologies and open standards, which provides the cross-border DTM and offers some capabilities of analysis and processing through the Internet. With this talk, the authors want to present the main steps of the project with a focus on the HELI-DEM geo-portal development carried out by the Institute of Earth Sciences, which is the access point to the DTM outputted from the project. The portal, accessible at http://geoservice.ist.supsi.ch/helidem, is a demonstration of open source technologies combined for providing access to geospatial functionalities to wide non GIS expert public. In fact, the system is entirely developed using only Open Standards and Free and Open Source Software (FOSS

  1. An improved method to represent DEM uncertainty in glacial lake outburst flood propagation using stochastic simulations

    NASA Astrophysics Data System (ADS)

    Watson, Cameron S.; Carrivick, Jonathan; Quincey, Duncan

    2015-10-01

    Modelling glacial lake outburst floods (GLOFs) or 'jökulhlaups', necessarily involves the propagation of large and often stochastic uncertainties throughout the source to impact process chain. Since flood routing is primarily a function of underlying topography, communication of digital elevation model (DEM) uncertainty should accompany such modelling efforts. Here, a new stochastic first-pass assessment technique was evaluated against an existing GIS-based model and an existing 1D hydrodynamic model, using three DEMs with different spatial resolution. The analysis revealed the effect of DEM uncertainty and model choice on several flood parameters and on the prediction of socio-economic impacts. Our new model, which we call MC-LCP (Monte Carlo Least Cost Path) and which is distributed in the supplementary information, demonstrated enhanced 'stability' when compared to the two existing methods, and this 'stability' was independent of DEM choice. The MC-LCP model outputs an uncertainty continuum within its extent, from which relative socio-economic risk can be evaluated. In a comparison of all DEM and model combinations, the Shuttle Radar Topography Mission (SRTM) DEM exhibited fewer artefacts compared to those with the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), and were comparable to those with a finer resolution Advanced Land Observing Satellite Panchromatic Remote-sensing Instrument for Stereo Mapping (ALOS PRISM) derived DEM. Overall, we contend that the variability we find between flood routing model results suggests that consideration of DEM uncertainty and pre-processing methods is important when assessing flow routing and when evaluating potential socio-economic implications of a GLOF event. Incorporation of a stochastic variable provides an illustration of uncertainty that is important when modelling and communicating assessments of an inherently complex process.

  2. 2D DEM model of sand transport with wind interaction

    NASA Astrophysics Data System (ADS)

    Oger, L.; Valance, A.

    2013-06-01

    The advance of the dunes in the desert is a threat to the life of the local people. The dunes invade houses, agricultural land and perturb the circulation on the roads. It is therefore very important to understand the mechanism of sand transport in order to fight against desertification. Saltation in which sand grains are propelled by the wind along the surface in short hops, is the primary mode of blown sand movement [1]. The saltating grains are very energetic and when impact a sand surface, they rebound and consequently eject other particles from the sand bed. The ejected grains, called reptating grains, contribute to the augmentation of the sand flux. Some of them can be promoted to the saltation motion. We use a mechanical model based on the Discrete Element Method to study successive collisions of incident energetic beads with granular packing in the context of Aeolian saltation transport. We investigate the collision process for the case where the incident bead and those from the packing have identical mechanical properties. We analyze the features of the consecutive collision processes made by the transport of the saltating disks by a wind in which its profile is obtained from the counter-interaction between air flow and grain flows. We used a molecular dynamics method known as DEM (soft Discrete Element Method) with a initial static packing of 20000 2D particles. The dilation of the upper surface due to the consecutive collisions is responsible for maintaining the flow at a given energy input due to the wind.

  3. Monitoring lava dome changes by means of differential DEMs from TanDEM-X interferometry: Examples from Merapi, Indonesia and Volcán de Colima, Mexico

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2013-12-01

    Estimating the amount of erupted material during a volcanic crisis is one of the major challenges in volcano research. One way to do this and to discriminate between juvenile and non-juvenile fraction is to assess topographic changes before and after an eruption while using area-wide 3D data. LiDAR or other airborne systems may be a good source, but the recording fails when clouds due to volcanic activity obstruct the sight. In addition, costs as well as logistics are high for local observatories. When dealing with dome-building volcanoes, acquiring the data gets further complicated. As the volcano dome can change rapidly in active phases, it is nearly impossible to collect data at the right time. However, when dealing with gross volume change estimates, at least two data sets - taken directly before and after the eruption - are essential. The innovative German Earth observation mission TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is of great importance to overcome some of these problems. The two almost identical radar satellites TerraSAR-X and TanDEM-X fly in a close formation, thus recording images of the same place on the Earth surface at the same time (bistatic mode). As the radar signal penetrates clouds, digital elevation models (DEMs) of the area of investigation can be generated without problems even with cloud cover. A time series analysis of the differential DEMs therefore opens the possibility to assess volume changes at active lava domes. We choose Merapi in Indonesia and Volcán de Colima in Mexico as test sites. Both volcanoes reside in a state of long term effusive eruption, interrupted every few years by phases of dome destruction, generation of pyroclastic flows and deposition of volcanic material. The availability of extensive ground truth data for both test sites further enables to validate the spaceborne data and results. Here, we analyze lava dome changes due to the hazardous Merapi 2010 eruption. We show a series of DEMs

  4. Comparison and Co-Registration of Dems Generated from HiRISE and Ctx Images

    NASA Astrophysics Data System (ADS)

    Wang, Yiran; Wu, Bo

    2016-06-01

    Images from two sensors, the High-Resolution Imaging Science Experiment (HiRISE) and the Context Camera (CTX), both on-board the Mars Reconnaissance Orbiter (MRO), were used to generate high-quality DEMs (Digital Elevation Models) of the Martian surface. However, there were discrepancies between the DEMs generated from the images acquired by these two sensors due to various reasons, such as variations in boresight alignment between the two sensors during the flight in the complex environment. This paper presents a systematic investigation of the discrepancies between the DEMs generated from the HiRISE and CTX images. A combined adjustment algorithm is presented for the co-registration of HiRISE and CTX DEMs. Experimental analysis was carried out using the HiRISE and CTX images collected at the Mars Rover landing site and several other typical regions. The results indicated that there were systematic offsets between the HiRISE and CTX DEMs in the longitude and latitude directions. However, the offset in the altitude was less obvious. After combined adjustment, the offsets were eliminated and the HiRISE and CTX DEMs were co-registered to each other. The presented research is of significance for the synergistic use of HiRISE and CTX images for precision Mars topographic mapping.

  5. ArcGeomorphometry: A toolbox for geomorphometric characterisation of DEMs in the ArcGIS environment

    NASA Astrophysics Data System (ADS)

    Rigol-Sanchez, Juan P.; Stuart, Neil; Pulido-Bosch, Antonio

    2015-12-01

    A software tool is described for the extraction of geomorphometric land surface variables and features from Digital Elevation Models (DEMs). The ArcGeomorphometry Toolbox consists of a series of Python/Numpy processing functions, presented through an easy-to-use graphical menu for the widely used ArcGIS package. Although many GIS provide some operations for analysing DEMs, the methods are often only partially implemented and can be difficult to find and used effectively. Since the results of automated characterisation of landscapes from DEMs are influenced by the extent being considered, the resolution of the source DEM and the size of the kernel (analysis window) used for processing, we have developed a tool to allow GIS users to flexibly apply several multi-scale analysis methods to parameterise and classify a DEM into discrete land surface units. Users can control the threshold values for land surface classifications. The size of the processing kernel can be used to identify land surface features across a range of landscape scales. The pattern of land surface units from each attempt at classification is displayed immediately and can then be processed in the GIS alongside additional data that can assist with a visual assessment and comparison of a series of results. The functionality of the ArcGeomorphometry toolbox is described using an example DEM.

  6. Shape and Albedo from Shading (SAfS) for Pixel-Level dem Generation from Monocular Images Constrained by Low-Resolution dem

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Chung Liu, Wai; Grumpe, Arne; Wöhler, Christian

    2016-06-01

    Lunar topographic information, e.g., lunar DEM (Digital Elevation Model), is very important for lunar exploration missions and scientific research. Lunar DEMs are typically generated from photogrammetric image processing or laser altimetry, of which photogrammetric methods require multiple stereo images of an area. DEMs generated from these methods are usually achieved by various interpolation techniques, leading to interpolation artifacts in the resulting DEM. On the other hand, photometric shape reconstruction, e.g., SfS (Shape from Shading), extensively studied in the field of Computer Vision has been introduced to pixel-level resolution DEM refinement. SfS methods have the ability to reconstruct pixel-wise terrain details that explain a given image of the terrain. If the terrain and its corresponding pixel-wise albedo were to be estimated simultaneously, this is a SAfS (Shape and Albedo from Shading) problem and it will be under-determined without additional information. Previous works show strong statistical regularities in albedo of natural objects, and this is even more logically valid in the case of lunar surface due to its lower surface albedo complexity than the Earth. In this paper we suggest a method that refines a lower-resolution DEM to pixel-level resolution given a monocular image of the coverage with known light source, at the same time we also estimate the corresponding pixel-wise albedo map. We regulate the behaviour of albedo and shape such that the optimized terrain and albedo are the likely solutions that explain the corresponding image. The parameters in the approach are optimized through a kernel-based relaxation framework to gain computational advantages. In this research we experimentally employ the Lunar-Lambertian model for reflectance modelling; the framework of the algorithm is expected to be independent of a specific reflectance model. Experiments are carried out using the monocular images from Lunar Reconnaissance Orbiter (LRO

  7. ALOS DEM quality assessment in a rugged topography, A Lebanese watershed as a case study

    NASA Astrophysics Data System (ADS)

    Abdallah, Chadi; El Hage, Mohamad; Termos, Samah; Abboud, Mohammad

    2014-05-01

    Deriving the morphometric descriptors of the Earth's surface from satellite images is a continuing application in remote sensing, which has been distinctly pushed with the increasing availability of DEMs at different scales, specifically those derived from high to very high-resolution stereoscopic and triscopic image data. The extraction of the morphometric descriptors is affected by the errors of the DEM. This study presents a procedure for assessing the quality of ALOS DEM in terms of position and morphometric indices. It involves evaluating the impact of the production parameters on the altimetric accuracy through checking height differences between Ground Control Points (GCP) and the corresponding DEM points, on the planimetric accuracy by comparing extracted drainage lines with topographic maps, and on the morphometric indices by comparing profiles extracted from the DEM with those measured on the field. A twenty set of triplet-stereo imagery from the PRISM instrument on the ALOS satellite has been processed to acquire a 5 m DEM covering the whole Lebanese territories. The Lebanese topography is characterized by its ruggedness with two parallel mountainous chains embedding a depression (The Bekaa Valley). The DEM was extracted via PCI Geomatica 2013. Each of the images required 15 GCPs and around 50 tie points. Field measurements was carried out using differential GPS (Trimble GeoXH6000, ProXRT receiver and the LaserACE 1000 Rangefinder) on Al Awali watershed (482 km2, about 5% of the Lebanese terrain). 3545 GPS points were collected at all ranges of elevation specifying the Lebanese terrain diversity, ranging from cliffy, to steep and gently undulating terrain along with narrow and wide flood plains and including predetermined profiles. Moreover, definite points such as road intersections and river beds were also measured in order to assess the extracted streams from the DEM. ArcGIS 10.1 was also utilized to extract the drainage network. Preliminary results

  8. Bathymetric survey of water reservoirs in north-eastern Brazil based on TanDEM-X satellite data.

    PubMed

    Zhang, Shuping; Foerster, Saskia; Medeiros, Pedro; de Araújo, José Carlos; Motagh, Mahdi; Waske, Bjoern

    2016-11-15

    Water scarcity in the dry season is a vital problem in dryland regions such as northeastern Brazil. Water supplies in these areas often come from numerous reservoirs of various sizes. However, inventory data for these reservoirs is often limited due to the expense and time required for their acquisition via field surveys, particularly in remote areas. Remote sensing techniques provide a valuable alternative to conventional reservoir bathymetric surveys for water resource management. In this study single pass TanDEM-X data acquired in bistatic mode were used to generate digital elevation models (DEMs) in the Madalena catchment, northeastern Brazil. Validation with differential global positioning system (DGPS) data from field measurements indicated an absolute elevation accuracy of approximately 1m for the TanDEM-X derived DEMs (TDX DEMs). The DEMs derived from TanDEM-X data acquired at low water levels show significant advantages over bathymetric maps derived from field survey, particularly with regard to coverage, evenly distributed measurements and replication of reservoir shape. Furthermore, by mapping the dry reservoir bottoms with TanDEM-X data, TDX DEMs are free of emergent and submerged macrophytes, independent of water depth (e.g. >10m), water quality and even weather conditions. Thus, the method is superior to other existing bathymetric mapping approaches, particularly for inland water bodies. The proposed approach relies on (nearly) dry reservoir conditions at times of image acquisition and is thus restricted to areas that show considerable water levels variations. However, comparisons between TDX DEM and the bathymetric map derived from field surveys show that the amount of water retained during the dry phase has only marginal impact on the total water volume derivation from TDX DEM. Overall, DEMs generated from bistatic TanDEM-X data acquired in low water periods constitute a useful and efficient data source for deriving reservoir bathymetry and show

  9. Recent Release of the ASTER Global DEM Product

    NASA Astrophysics Data System (ADS)

    Behnke, J.; Hall, A.; Meyer, D.; Sohre, T.; Doescher, C.

    2009-12-01

    On June 29th, the ASTER Global Digital Elevation Model (DEM) release was announced to the public and to a very eager audience. ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is an imaging instrument flying on Terra, a satellite launched in December 1999 as part of NASA's Earth Observing System (EOS). ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI) and Japan's Earth Remote Sensing Data Analysis Center (ERSDAC). On June 21, NASA Headquarters along with colleagues in Japan (METI) signed a plan for distribution of this product. The global digital elevation model of Earth is available online to users everywhere at no cost from NASA's Land Processes Distributed Active Archive Center (DAAC) located at Sioux Falls, SD. The DAAC is a joint project of NASA and the USGS and is a key component of NASA's EOSDIS. The new ASTER GDEM was created from nearly 1.3 million individual stereo-pair images acquired by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) instrument aboard NASA’s Terra satellite. The ASTER elevation model was jointly developed by NASA and METI under contract to Sensor Information Laboratory Corp., Tsukuba, Japan. On June 29, the NASA press release was picked up quickly by numerous news organizations and online sites. Response to the product was incredible! The news of the release of the product was carried on websites across the globe, this fueled a tremendous response from users. Here are a few interesting metrics about the release: - over 41,000 unique visitors to website in first week following release - top countries in order were: US (approx. 20%), Germany, U.K., Brazil, Austria, Canada, Spain, Switzerland, Japan - approximately 29,000 visitors came to the news page in the first week and about 11,000 of these users downloaded the actual press release - by the end of August, over 2 Million ASTER GDEM files had been downloaded from the Land

  10. Friedrich Möglich - sein Beitrag zum Aufbau der Physik in der DDR. Friedrich Möglich - langjähriger Mitherausgeber und Chefredakteur der Annalen der Physik

    NASA Astrophysics Data System (ADS)

    Rompe, Robert

    Friedrich Möglich, ein Schüler von Max von Laue und Erwin Schrödinger, übernahm 1947 die Chefredaktion der Annalen der Physik.Translated AbstractFriedrich Möglich - His Contributions to the Formation of Physics in GDRFriedrich Möglich a student of Max von Laue and Erwin Schrödinger took over as editor in chief of Annalen der Physik in 1947.

  11. CFD-DEM simulations of current-induced dune formation and morphological evolution

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Xiao, Heng

    2016-06-01

    Understanding the fundamental mechanisms of sediment transport, particularly those during the formation and evolution of bedforms, is of critical scientific importance and has engineering relevance. Traditional approaches of sediment transport simulations heavily rely on empirical models, which are not able to capture the physics-rich, regime-dependent behaviors of the process. With the increase of available computational resources in the past decade, CFD-DEM (computational fluid dynamics-discrete element method) has emerged as a viable high-fidelity method for the study of sediment transport. However, a comprehensive, quantitative study of the generation and migration of different sediment bed patterns using CFD-DEM is still lacking. In this work, current-induced sediment transport problems in a wide range of regimes are simulated, including 'flat bed in motion', 'small dune', 'vortex dune' and suspended transport. Simulations are performed by using SediFoam, an open-source, massively parallel CFD-DEM solver developed by the authors. This is a general-purpose solver for particle-laden flows tailed for particle transport problems. Validation tests are performed to demonstrate the capability of CFD-DEM in the full range of sediment transport regimes. Comparison of simulation results with experimental and numerical benchmark data demonstrates the merits of CFD-DEM approach. In addition, the improvements of the present simulations over existing studies using CFD-DEM are presented. The present solver gives more accurate prediction of sediment transport rate by properly accounting for the influence of particle volume fraction on the fluid flow. In summary, this work demonstrates that CFD-DEM is a promising particle-resolving approach for probing the physics of current-induced sediment transport.

  12. Error modeling of DEMs from topographic surveys of rivers using fuzzy inference systems

    NASA Astrophysics Data System (ADS)

    Bangen, Sara; Hensleigh, James; McHugh, Peter; Wheaton, Joseph

    2016-02-01

    Digital elevation models (DEMs) have become common place in the earth sciences as a tool to characterize surface topography and set modeling boundary conditions. All DEMs have a degree of inherent error that is propagated to subsequent models and analyses. While previous research has shown that DEM error is spatially variable it is often represented as spatially uniform for analytical simplicity. Fuzzy inference systems (FIS) offer a tractable approach for modeling spatially variable DEM error, including flexibility in the number of inputs and calibration of outputs based on survey technique and modeling environment. We compare three FIS error models for DEMs derived from TS surveys of wadeable streams and test them at 34 sites in the Columbia River basin. The models differ in complexity regarding the number/type of inputs and degree of site-specific parameterization. A 2-input FIS uses inputs derived from the topographic point cloud (slope, point density). A 4-input FIS adds interpolation error and 3-D point quality. The 5-input FIS adds bed-surface roughness estimates. Both the 4 and 5-input FIS model output were parameterized to site-specific values. In the wetted channel we found (i) the 5-input FIS resulted in lower mean δz due to including roughness, and (ii) the 4 and 5-input FIS resulted in a higher standard deviation and maximum δz due to the inclusion of site-specific bank heights. All three FIS gave plausible estimates of DEM error, with the two more complicated models offering an improvement in the ability to detect spatially localized areas of DEM uncertainty.

  13. Perspective - synthetic DEMs: A vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Sofia, G.; Conway, S. J.

    2015-12-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g. Earth's). A fundamental tenet of geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Artificial or synthetic digital elevation models (DEMs) might be vital in progressing further with this endeavour in two ways. First, synthetic DEMs can be built (e.g. by directly using governing equations) to encapsulate the processes, making predictions from theory. A second, arguably underutilised, role is to perform checks on accuracy and robustness that we dub "synthetic tests". Specifically, synthetic DEMs can contain a priori known, idealised morphologies that numerical landscape evolution models, DEM-analysis algorithms, and even manual mapping can be assessed against. Some such tests, for instance examining inaccuracies caused by noise, are moderately commonly employed, whilst others are much less so. Derived morphological properties, including metrics and mapping (manual and automated), are required to establish whether or not conceptual models represent reality well, but at present their quality is typically weakly constrained (e.g. by mapper inter-comparison). Relatively rare examples illustrate how synthetic tests can make strong "absolute" statements about landform detection and quantification; for example, 84 % of valley heads in the real landscape are identified correctly. From our perspective, it is vital to verify such statistics quantifying the properties of landscapes as ultimately this is the link between physics-driven models of processes and morphological observations that allows quantitative hypotheses to be tested. As such the additional rigour possible with this second usage of synthetic DEMs feeds directly into a problem central to the validity of much of geomorphology. Thus, this note introduces synthetic tests and DEMs and then outlines a typology of synthetic DEMs along with their benefits

  14. Kosmische Weiten. Kurze Geschichte der Entfernungsmessung im Weltall.

    NASA Astrophysics Data System (ADS)

    Herrmann, D. B.

    Contents: 1. Einleitung. 2. Trigonometrische (jährliche) Fixsternparallaxen. 3. Fotometrische Parallaxen. 4. Überblick über weitere Methoden der Entfernungsbestimmung. 5. Entfernungen der extragalaktischen Objekte. 6. Ausblick. 7. Elementare Grundlagen der Entfernungsbestimmung.

  15. Von Humboldt bis Einstein. Berlin als Weltzentrum der exakten Wissenschaften.

    NASA Astrophysics Data System (ADS)

    Meschkowski, H.

    Contents: 1. Die Anfänge. 2. Die Ära Dirichlet-Jacobi. 3. Der Ausbau der experimentellen Naturwissenschaften. 4. Alexander von Humboldt. 5. Berlin wird "Weltzentrum" der Mathematik. 6. Die Ära Helmholtz. 7. Neue Arbeitsweisen der Astronomie. 8. Chemie: Forschung und Industrie. 9. Max Planck. 10. Ins technische Zeitalter. 11. Zur Mathematik der zwanziger Jahre. 12. Albert Einstein. 13. Fortschritte der Grundlagenforschung. 14. Erwin Schrödinger: Physiker, Philosoph und Poet. 15. Zum Schluß.

  16. Acute environmental toxicity and persistence of DEM, a chemical agent simulant: Diethyl malonate. [Diethyl malonate

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, Shu-mei W.; Van Voris, P.; Wentsel, R.S.

    1990-05-01

    The purpose of the following chemical simulant studies is to assess the potential acute environmental effects and persistence of diethyl malonate (DEM). Deposition velocities for DEM to soil surfaces ranged from 0.04 to 0.2 cm/sec. For foliar surfaces, deposition velocities ranged from 0.0002 cm/sec at low air concentrations to 0.05 cm/sec for high dose levels. The residence times or half-lives of DEM deposited to soils was 2 h for the fast component and 5 to 16 h for the residual material. DEM deposited to foliar surfaces also exhibited biphasic depuration. The half-life of the short residence time component ranged from 1 to 3 h, while the longer time component had half-times of 16 to 242 h. Volatilization and other depuration mechanisms reduce surface contaminant levels in both soils and foliage to less than 1% of initial dose within 96 h. DEM is not phytotoxic at foliar mass loading levels of less than 10 {mu}m/cm{sup 2}. However, severe damage is evident at mass loading levels in excess of 17 {mu}g/cm{sup 2}. Tall fescue and sagebrush were more affected than was short-needle pine, however, mass loading levels were markedly different. Regrowth of tall fescue indicated that the effects of DEM are residual, and growth rates are affected only at higher mass loadings through the second harvest. Results from in vitro testing of DEM indicated concentrations below 500 {mu}g/g dry soil generally did not negatively impact soil microbial activity. Short-term effects of DEM were more profound on soil dehydrogenase activity than on soil phosphatase activity. No enzyme inhibition or enhancement was observed after 28 days in incubation. Results of the earthworm bioassay indicate survival to be 86 and 66% at soil doses of 107 and 204 {mu}g DEM/cm{sup 2}, respectively. At higher dose level, activity or mobility was judged to be affected in over 50% of the individuals. 21 refs., 10 figs., 15 tabs.

  17. Optimizing grid computing configuration and scheduling for geospatial analysis: An example with interpolating DEM

    NASA Astrophysics Data System (ADS)

    Huang, Qunying; Yang, Chaowei

    2011-02-01

    Many geographic analyses are very time-consuming and do not scale well when large datasets are involved. For example, the interpolation of DEMs (digital evaluation model) for large geographic areas could become a problem in practical application, especially for web applications such as terrain visualization, where a fast response is required and computational demands exceed the capacity of a traditional single processing unit conducting serial processing. Therefore, high performance and parallel computing approaches, such as grid computing, were investigated to speed up the geographic analysis algorithms, such as DEM interpolation. The key for grid computing is to configure an optimized grid computing platform for the geospatial analysis and optimally schedule the geospatial tasks within a grid platform. However, there is no research focused on this. Using DEM interoperation as an example, we report our systematic research on configuring and scheduling a high performance grid computing platform to improve the performance of geographic analyses through a systematic study on how the number of cores, processors, grid nodes, different network connections and concurrent request impact the speedup of geospatial analyses. Condor, a grid middleware, is used to schedule the DEM interpolation tasks for different grid configurations. A Kansas raster-based DEM is used for a case study and an inverse distance weighting (IDW) algorithm is used in interpolation experiments.

  18. TecDEM: A MATLAB Based Toolbox for understanding Tectonics from Digital Elevation Models

    NASA Astrophysics Data System (ADS)

    Shahzad, F.; Mahmood, S. A.; Gloaguen, R.

    2009-04-01

    TecDEM is a MATLAB based tool box for understanding the tectonics from digital elevation models (DEMs) of any area. These DEMs can be derived from data of any spatial resolution (Low, medium and High). In the first step we extract drainage network from the DEMs using flow grid approach. Drainage network is a group of streams having elevation and catchment area information as a function of spatial locations. We implement an array of stream structure to study this drainage network. Knickpoints can be identified on each stream of the drainage network by a graphical user interface and are helpful for understanding stream morphology. Stream profile analysis in steady state condition is applied on all streams to calculate geomorphic parameters and regional uplift rates. Hack index is calculated for all the profiles at a certain interval and over the change of knickpoints. Reports menu of this tool box generates detailed statistics report, complete tabulated report, graphical output of each analyzed stream profile and Hack index profile. All the calculated values are part of stream structure and is saved as .mat file for later use with this tool box. The spatial distribution of geomorphic parameters, uplift rates and knickpoints are exported as a shape files for visualization in professional GIS software. We test this tool box on DEMs from different tectonic settings worldwide and received verifiable results with other studies.

  19. DEM Extraction from High-Resolution Stereoscopic Worldview 1 & 2 Imagery of Polar Outlet Glaciers

    NASA Astrophysics Data System (ADS)

    Porter, C. C.; Morin, P. J.; Howat, I. M.; Niebuhr, S.; Smith, B. E.

    2011-12-01

    There are few reliable digital elevation models (DEMs) in polar regions and most are of low resolution (on the order of 100's of meters to km) or of poor quality. Polar environments are changing rapidly and accurate DEMs are critical for correcting imagery, measuring glacier thickness changes and modeling ice flow and surface melt water drainage. Using in-track stereoscopic images from Worldview-1 and Worldview-2, we derived high-resolution DEMs for outlet glaciers and other areas of interest in Antarctica and the Arctic. We used ERDAS Imagine's LPS eATE (enhanced automated terrain extraction) algorithm to derive a dense point cloud of matches. The resulting point cloud is comparable in density to that obtained by LiDAR flown at 10,000 feet. Preliminary comparisons of our results to ground control points collected by field teams and airborne and satellite laser altimeters show 0.5 - 10 meter vertical error over glaciers and 2 - 10 meter error over ice-free terrain. The error is primarily due to approximations in the sensor model and is consistent across the DEM. Our results indicate that refinements in the sensor model and point matching algorithm will improve accuracy. Given the increasing interest in glacier change detection around the globe, DEMs extracted from frequent satellite stereo pairs can be used to monitor and quantify changes in both movement and volume.

  20. Perspective - synthetic DEMs: a vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Sofia, G.; Conway, S. J.

    2015-07-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g., Earth's). A fundamental tenet of Geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Artificial or synthetic Digital Elevation Models (DEMs) might be vital in progressing further with this endeavour. Morphological data, including metrics and mapping (manual and automated) are a key resource, but at present their quality is typically weakly constrained (e.g., by mapper inter-comparison). In addition to examining inaccuracies caused by noise, relatively rare examples illustrate how synthetic DEMs containing a priori known, idealised morphologies can be used perform "synthetic tests" to make strong "absolute" statements about landform detection and quantification; e.g., 84 % of valley heads in the real landscape are identified correctly. From our perspective, it is vital to verify such statistics as ultimately they link physics-driven models of processes to morphological observations, allowing quantitative hypotheses to be formulated and tested. Synthetic DEMs built by directly using governing equations that encapsulate processes are another key part of forming this link. Thus, this note introduces synthetic tests and DEMs, then it outlines a typology of synthetic DEMs along with their benefits, challenges and future potential to provide constraints and insights. The aim is to discuss how we best proceed with uncertainty-aware landscape analysis to examine physical processes.

  1. Geomorphic change detection using historic maps and DEM differencing: The temporal dimension of geospatial analysis

    NASA Astrophysics Data System (ADS)

    James, L. Allan; Hodgson, Michael E.; Ghoshal, Subhajit; Latiolais, Mary Megison

    2012-01-01

    The ability to develop spatially distributed models of topographic change is presenting new capabilities in geomorphic research. High resolution maps of elevation change indicate locations, processes, and rates of geomorphic change, and provide a means of calibrating temporal simulation models. Methods of geomorphic change detection (GCD), based on gridded models, may be applied to a wide range of time periods by utilizing cartometric, remote sensing, or ground-based topographic survey data to measure volumetric change. Advantages and limitations of historical DEM reconstruction methods are reviewed with a focus on coupling them with subsequent DEMs to construct DEMs of difference (DoD), which can be created by subtracting one elevation model from another, to map erosion, deposition, and volumetric change. The period of DoD analysis can be extended to several decades if accurate historical DEMs can be generated by extracting topographic data from historical data and selecting areas where geomorphic change has been substantial. The challenge is to recognize and minimize uncertainties in data that are particularly elusive with early topographic data. This paper reviews potential sources of error in digitized topographic maps and DEMs. Although the paper is primarily a review of methods, three brief examples are presented at the end to demonstrate GCD using DoDs constructed from data extending over periods ranging from 70 to 90 years.

  2. Wilhelm Julius Foerster und die "Vereinigung von Freunden der Astronomie und kosmischen Physik" (1891 bis 1914).

    NASA Astrophysics Data System (ADS)

    Tiemann, K.-H.

    Am 19. Mai 1891 wurde ins Leben gerufen die "Vereinigung von Freunden der Astronomie und der kosmischen Physik (nachfolg.: V.A.P.) - eine der beiden institutionellen Vorläufer der sich 1953 konstituierenden "Vereinigung der Sternfreunde".

  3. Erlebniseinkauf in der Innenstadt mit hoher Akzeptanz

    NASA Astrophysics Data System (ADS)

    Pangels, Rolf

    2002-03-01

    Im Oktober 2000 führte die BAG zum zehnten Mal die über die Grenzen des Einzelhandels bekannte Untersuchung "Kundenverkehr" in mehr als hundertfünfzig deutschen Städten durch. In Kooperation mit der Swiss Retail Federation sowie mit Unterstützung der femged (European Federation of Medium-size and Major Retailers) wurde die Untersuchung erstmals auch in der Schweiz und in Österreich durchgeführt. Es beteiligten sich insgesamt 463 Unternehmen an der Untersuchung, die knapp 9,5 Mio. Besucher gezählt haben und davon mehr als 360.000 Kunden nach bestimmten Parametern befragten. Die Daten für Deutschland wurden, wie in den Jahren zuvor, vom Institut für Handelsforschung an der Universität Köln ausgewertet. Die Zahlen der Untersuchung in der Schweiz und Österreich wurden von der wirtschafts- und sozialwissenschaftlichen Beratungsgesellschaft ECON-Consult in Köln zusammengetragen und analysiert.

  4. A simple FEM-DEM technique for fracture prediction in materials and structures

    NASA Astrophysics Data System (ADS)

    Zárate, Francisco; Oñate, Eugenio

    2015-09-01

    This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method (FEM) and the discrete element method (DEM). Onset of cracking at a point is governed by a simple damage model. Once a crack is detected at an element side in the FE mesh, discrete elements are generated at the nodes sharing the side and a simple DEM mechanism is considered to follow the evolution of the crack. The combination of the DEM with simple 3-noded linear triangular elements correctly captures the onset of fracture and its evolution, as shown in several examples of application in two and three dimensions.

  5. A Detailed Observation of a LMC SNR, DEM L241, with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bamba, Aya; Ueno, Masaru; Nakajima, Hiroshi; Mori, Koji; Koyama, Katsuji

    We report on an XMM-Newton observation of the supernova remnant (SNR) DEM L241 in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish (Head and Tail), with a central point source, named as XMMU J053559.3-673509 (Eye). The Eye's spectrum is well reproduced with a power-law model. The source has neither significant coherent pulsations nor time variabilities. Its luminosity and spectrum remind us that the source might be a pulsar and/or pulsar wind nebula in DEM L241. The spectra of Head and Tail are well reproduced by a non-equilibrium ionization plasma model with over-abundant Ne and under-abundant Fe, suggesting that the progenitor of DEM L241 is a very massive star.

  6. GPS-Based Precision Baseline Reconstruction for the TanDEM-X SAR-Formation

    NASA Technical Reports Server (NTRS)

    Montenbruck, O.; vanBarneveld, P. W. L.; Yoon, Y.; Visser, P. N. A. M.

    2007-01-01

    The TanDEM-X formation employs two separate spacecraft to collect interferometric Synthetic Aperture Radar (SAR) measurements over baselines of about 1 km. These will allow the generation ofa global Digital Elevation Model (DEM) with an relative vertical accuracy of 2-4 m and a 10 m ground resolution. As part of the ground processing, the separation of the SAR antennas at the time of each data take must be reconstructed with a 1 mm accuracy using measurements from two geodetic grade GPS receivers. The paper discusses the TanDEM-X mission as well as the methods employed for determining the interferometric baseline with utmost precision. Measurements collected during the close fly-by of the two GRACE satellites serve as a reference case to illustrate the processing concept, expected accuracy and quality control strategies.

  7. The Effect of DEM Quality on Sea Level Rise Exposure Analysis

    NASA Astrophysics Data System (ADS)

    Kulp, S. A.; Strauss, B.

    2015-12-01

    Sea level rise (SLR) caused by climate change could cause significant disruptions in coastal communities across the world. Current projections estimate that we may see in the vicinity of 1 meter of SLR by the end of the century, and due to collapsing ice sheets in West Antarctica, more than 3 meters of global SLR appear very likely in the long run. It is therefore crucial that we begin to accurately understand both the short- and long-term effects this level of flooding could have on each country's land area and population. However, while we have high-resolution digital elevation models (DEMs) publicly available for some parts of the world, such as the coastal lidar datasets distributed by NOAA for the US, most of the rest of the world is only covered by much poorer-quality data, such as data from SRTM (3 arcsec, or roughly 90m, horizontal resolution). In this work, we perform SLR analysis using both NOAA lidar- and SRTM-derived DEMs in the United States, in order to understand how using low-quality DEMs affect the final analysis results. We find that in many states, the computed population exposure at 1 meter SLR is over 2x higher when using the Lidar DEM, compared to the results computed from SRTM. In addition to the clear differences in horizontal resolution, this very large difference in computed exposure could likely be explained by the fact that SRTM is based on surface elevation, while the Lidar DEM is based on bare earth elevation. We therefore conclude that any worldwide SLR analysis using SRTM would produce exposure estimates that are far too low, and higher-quality global DEMs are necessary in order to generate exposure analysis of reasonable accuracy.

  8. Sediment Transport Simulations Coupling DEM with RANS Fluid Solver in Multi- dimensions

    NASA Astrophysics Data System (ADS)

    Calantoni, J.; Torres-Freyermuth, A.; Hsu, T.

    2008-12-01

    Multiphase simulations of the sediment-water interface in a wave bottom boundary layer are accomplished by using a Reynolds averaged Navier Stokes (RANS) fluid solver for water motions coupled to the discrete element method (DEM) for modeling the motions of individual sediment grains. Turbulence closure in the ensemble-averaged fluid-phase equations uses balance equations for fluid turbulent kinetic energy and its dissipation rate. Both 1DV and 2DV implementations of the RANS fluid solver have been coupled to the DEM. In both cases, the DEM is fully three-dimensional where sediment particles have spherical shape and point contacts are assumed with normal and tangential forces at the contact point between particle pairs modeled with springs and friction, respectively. Coupling between sediment-water phases varies from simple one-way coupling where fluid drives sediment motions with no feedback from the sediment, up to fully coupled continuity equations and turbulence closure as well as in the fluid momentum equations where Newton's Third Law is strictly enforced at every fluid time step. Fluid-particle interaction forces include drag, added mass, pressure gradient forces, and turbulent suspension implemented through an eddy-particle interaction model based on a random walk. The 1DV DEM-RANS coupled model was used to simulate sheet flow transport conditions under oscillatory flows. The 2DV DEM-RANS coupled model was used to simulate suspension and transport over small-scale sand ripples. For all cases, the DEM used coarse to fine (0.4 mm - 0.2 mm diameter) sized sediments where grain-grain interactions model viscous dissipation through an effective coefficient of restitution as a function of the collisional Stokes number estimated from published laboratory measurements of particle-particle and particle-wall collisions. Initial comparisons were made with laboratory U-tube measurements for bulk transport rates and time-dependent concentration profiles for sheet flow

  9. Leitbilder und Handlungsstrategien für die Raumentwicklung in Deutschland. Entwicklungs-, Umsetzungs- und Fortschreibungsprozess der Bund-Länder-Strategie für Städte und Regionen

    NASA Astrophysics Data System (ADS)

    Issaoui, Mariam; Sinz, Manfred

    2010-09-01

    Die Ministerkonferenz für Raumordnung stellte im Mai 2010 fest, dass sich die „Leitbilder und Handlungsstrategien für die Raumentwicklung in Deutschland“ (2006) bewährt haben und bei der Gestaltung der räumlichen Entwicklung umgesetzt werden. Um die Leitbilder den sich verändernden wirtschaftlichen, sozialen und naturräumlichen Rahmenbedingungen anzupassen und die Erkenntnisse aus dem bisherigen Diskussions- und Umsetzungsprozess in Politik und Praxis einzubeziehen, sind sie zu ergänzen und weiterzuentwickeln. Im Mittelpunkt der Fortschreibung werden die Themen „Partnerschaften und Strategien für Stadtregionen und ländliche Räume“, „Mobilität und Logistik“ sowie „Klimaschutz und Energieversorgung“ stehen.

  10. Developmental Eye Movement (DEM) Test Norms for Mandarin Chinese-Speaking Chinese Children

    PubMed Central

    Tong, Meiling; Zhang, Min; Li, Tingting; Xu, Yaqin; Guo, Xirong; Hong, Qin; Chi, Xia

    2016-01-01

    The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool to screen and diagnose reading problems at the onset. No established norm exists for using the DEM test with Mandarin Chinese-speaking Chinese children. This study aims to establish the normative values of the DEM test for the Mandarin Chinese-speaking population in China; it also aims to compare the values with three other published norms for English-, Spanish-, and Cantonese-speaking Chinese children. A random stratified sampling method was used to recruit children from eight kindergartens and eight primary schools in the main urban and suburban areas of Nanjing. A total of 1,425 Mandarin Chinese-speaking children aged 5 to 12 years took the DEM test in Mandarin Chinese. A digital recorder was used to record the process. All of the subjects completed a symptomatology survey, and their DEM scores were determined by a trained tester. The scores were computed using the formula in the DEM manual, except that the “vertical scores” were adjusted by taking the vertical errors into consideration. The results were compared with the three other published norms. In our subjects, a general decrease with age was observed for the four eye movement indexes: vertical score, adjusted horizontal score, ratio, and total error. For both the vertical and adjusted horizontal scores, the Mandarin Chinese-speaking children completed the tests much more quickly than the norms for English- and Spanish-speaking children. However, the same group completed the test slightly more slowly than the norms for Cantonese-speaking children. The differences in the means were significant (P<0.001) in all age groups. For several ages, the scores obtained in this study were significantly different from the reported scores of Cantonese-speaking Chinese children (P<0.005). Compared with English-speaking children, only the vertical score of the 6-year-old group, the vertical

  11. Stochastic Discrete Equation Method (sDEM) for two-phase flows

    SciTech Connect

    Abgrall, R.; Congedo, P.M.; Geraci, G.; Rodio, M.G.

    2015-10-15

    A new scheme for the numerical approximation of a five-equation model taking into account Uncertainty Quantification (UQ) is presented. In particular, the Discrete Equation Method (DEM) for the discretization of the five-equation model is modified for including a formulation based on the adaptive Semi-Intrusive (aSI) scheme, thus yielding a new intrusive scheme (sDEM) for simulating stochastic two-phase flows. Some reference test-cases are performed in order to demonstrate the convergence properties and the efficiency of the overall scheme. The propagation of initial conditions uncertainties is evaluated in terms of mean and variance of several thermodynamic properties of the two phases.

  12. PRO DEM: A Community-Based Approach to Care for Dementia

    PubMed Central

    Hesse, Eberhard

    2005-01-01

    Physicians in a region south of Bremen, Germany, created PRO DEM (for patients with dementia), a service coordinating medical care and social intervention for patients with dementia. The program now serves about 125 outpatients and their families, along with 360 patients in nursing homes. Two nurse consultants coordinate patient care. Treatment strategies are decided during a multidisciplinary case conference among physicians, nurses, and other professionals. Social intervention modules include various care groups for patients and respite services for caregivers. PRO DEM aims to provide fully coordinated care for a better quality of life for patients and caregivers, delaying nursing home admission as long as possible. PMID:17288081

  13. Developmental Eye Movement (DEM) Test Norms for Mandarin Chinese-Speaking Chinese Children.

    PubMed

    Xie, Yachun; Shi, Chunmei; Tong, Meiling; Zhang, Min; Li, Tingting; Xu, Yaqin; Guo, Xirong; Hong, Qin; Chi, Xia

    2016-01-01

    The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool to screen and diagnose reading problems at the onset. No established norm exists for using the DEM test with Mandarin Chinese-speaking Chinese children. This study aims to establish the normative values of the DEM test for the Mandarin Chinese-speaking population in China; it also aims to compare the values with three other published norms for English-, Spanish-, and Cantonese-speaking Chinese children. A random stratified sampling method was used to recruit children from eight kindergartens and eight primary schools in the main urban and suburban areas of Nanjing. A total of 1,425 Mandarin Chinese-speaking children aged 5 to 12 years took the DEM test in Mandarin Chinese. A digital recorder was used to record the process. All of the subjects completed a symptomatology survey, and their DEM scores were determined by a trained tester. The scores were computed using the formula in the DEM manual, except that the "vertical scores" were adjusted by taking the vertical errors into consideration. The results were compared with the three other published norms. In our subjects, a general decrease with age was observed for the four eye movement indexes: vertical score, adjusted horizontal score, ratio, and total error. For both the vertical and adjusted horizontal scores, the Mandarin Chinese-speaking children completed the tests much more quickly than the norms for English- and Spanish-speaking children. However, the same group completed the test slightly more slowly than the norms for Cantonese-speaking children. The differences in the means were significant (P<0.001) in all age groups. For several ages, the scores obtained in this study were significantly different from the reported scores of Cantonese-speaking Chinese children (P<0.005). Compared with English-speaking children, only the vertical score of the 6-year-old group, the vertical-horizontal time

  14. Developmental Eye Movement (DEM) Test Norms for Mandarin Chinese-Speaking Chinese Children.

    PubMed

    Xie, Yachun; Shi, Chunmei; Tong, Meiling; Zhang, Min; Li, Tingting; Xu, Yaqin; Guo, Xirong; Hong, Qin; Chi, Xia

    2016-01-01

    The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool to screen and diagnose reading problems at the onset. No established norm exists for using the DEM test with Mandarin Chinese-speaking Chinese children. This study aims to establish the normative values of the DEM test for the Mandarin Chinese-speaking population in China; it also aims to compare the values with three other published norms for English-, Spanish-, and Cantonese-speaking Chinese children. A random stratified sampling method was used to recruit children from eight kindergartens and eight primary schools in the main urban and suburban areas of Nanjing. A total of 1,425 Mandarin Chinese-speaking children aged 5 to 12 years took the DEM test in Mandarin Chinese. A digital recorder was used to record the process. All of the subjects completed a symptomatology survey, and their DEM scores were determined by a trained tester. The scores were computed using the formula in the DEM manual, except that the "vertical scores" were adjusted by taking the vertical errors into consideration. The results were compared with the three other published norms. In our subjects, a general decrease with age was observed for the four eye movement indexes: vertical score, adjusted horizontal score, ratio, and total error. For both the vertical and adjusted horizontal scores, the Mandarin Chinese-speaking children completed the tests much more quickly than the norms for English- and Spanish-speaking children. However, the same group completed the test slightly more slowly than the norms for Cantonese-speaking children. The differences in the means were significant (P<0.001) in all age groups. For several ages, the scores obtained in this study were significantly different from the reported scores of Cantonese-speaking Chinese children (P<0.005). Compared with English-speaking children, only the vertical score of the 6-year-old group, the vertical-horizontal time

  15. Influence of Lossy Compressed DEM on Radiometric Correction for Land Cover Classification of Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Moré, G.; Pesquer, L.; Blanes, I.; Serra-Sagristà, J.; Pons, X.

    2012-12-01

    World coverage Digital Elevation Models (DEM) have progressively increased their spatial resolution (e.g., ETOPO, SRTM, or Aster GDEM) and, consequently, their storage requirements. On the other hand, lossy data compression facilitates accessing, sharing and transmitting large spatial datasets in environments with limited storage. However, since lossy compression modifies the original information, rigorous studies are needed to understand its effects and consequences. The present work analyzes the influence of DEM quality -modified by lossy compression-, on the radiometric correction of remote sensing imagery, and the eventual propagation of the uncertainty in the resulting land cover classification. Radiometric correction is usually composed of two parts: atmospheric correction and topographical correction. For topographical correction, DEM provides the altimetry information that allows modeling the incidence radiation on terrain surface (cast shadows, self shadows, etc). To quantify the effects of the DEM lossy compression on the radiometric correction, we use radiometrically corrected images for classification purposes, and compare the accuracy of two standard coding techniques for a wide range of compression ratios. The DEM has been obtained by resampling the DEM v.2 of Catalonia (ICC), originally having 15 m resolution, to the Landsat TM resolution. The Aster DEM has been used to fill the gaps beyond the administrative limits of Catalonia. The DEM has been lossy compressed with two coding standards at compression ratios 5:1, 10:1, 20:1, 100:1 and 200:1. The employed coding standards have been JPEG2000 and CCSDS-IDC; the former is an international ISO/ITU-T standard for almost any type of images, while the latter is a recommendation of the CCSDS consortium for mono-component remote sensing images. Both techniques are wavelet-based followed by an entropy-coding stage. Also, for large compression ratios, both techniques need a post processing for correctly

  16. Evaluating DEM conditioning techniques, elevation source data, and grid resolution for field-scale hydrological parameter extraction

    NASA Astrophysics Data System (ADS)

    Woodrow, Kathryn; Lindsay, John B.; Berg, Aaron A.

    2016-09-01

    Although digital elevation models (DEMs) prove useful for a number of hydrological applications, they are often the end result of numerous processing steps that each contains uncertainty. These uncertainties have the potential to greatly influence DEM quality and to further propagate to DEM-derived attributes including derived surface and near-surface drainage patterns. This research examines the impacts of DEM grid resolution, elevation source data, and conditioning techniques on the spatial and statistical distribution of field-scale hydrological attributes for a 12,000 ha watershed of an agricultural area within southwestern Ontario, Canada. Three conditioning techniques, including depression filling (DF), depression breaching (DB), and stream burning (SB), were examined. The catchments draining to each boundary of 7933 agricultural fields were delineated using the surface drainage patterns modeled from LiDAR data, interpolated to a 1 m, 5 m, and 10 m resolution DEMs, and from a 10 m resolution photogrammetric DEM. The results showed that variation in DEM grid resolution resulted in significant differences in the spatial and statistical distributions of contributing areas and the distributions of downslope flowpath length. Degrading the grid resolution of the LiDAR data from 1 m to 10 m resulted in a disagreement in mapped contributing areas of between 29.4% and 37.3% of the study area, depending on the DEM conditioning technique. The disagreements among the field-scale contributing areas mapped from the 10 m LiDAR DEM and photogrammetric DEM were large, with nearly half of the study area draining to alternate field boundaries. Differences in derived contributing areas and flowpaths among various conditioning techniques increased substantially at finer grid resolutions, with the largest disagreement among mapped contributing areas occurring between the 1 m resolution DB DEM and the SB DEM (37% disagreement) and the DB-DF comparison (36.5% disagreement in mapped

  17. Lidar DEM error analyses and topographic depression identification in a hummocky landscape in the prairie region of Canada

    NASA Astrophysics Data System (ADS)

    Li, Sheng; MacMillan, R. A.; Lobb, David A.; McConkey, Brian G.; Moulin, Alan; Fraser, Walter R.

    2011-06-01

    Topographic depressions are abundant in topographically complex landscapes. A common practice with earlier, low resolution Digital Elevation Models (DEMs) was to remove all depressions to ensure that water flowed continuously to the edge of the DEM domain. The assumption was that most depressions were created due to errors in the DEMs. This practice is no longer justified with the increasing availability of high accuracy DEMs. However, very few studies have addressed how DEM processing options such as smoothing and coarsening and setting area and depth thresholds can affect depression identification. In this study, a site located in the Prairie Region of Canada was examined. The site is a hummocky glaciated landscape with many in-field wetlands. Lidar topographic data were collected and were used to generate a 1 m by 1 m square-grid DEM. Detailed error analyses of the lidar DEM were conducted. A set of DEMs were generated after different degrees of smoothing and coarsening. FlowMapR, an established terrain analysis tool, was used to identify depressions in each DEM with various user-defined area and depth thresholds. The results were validated against a field wetland survey. We determined that the problems associated with depression identification using a lidar DEM are two-fold. On one hand, artefactual depressions created due to DEM errors need to be eliminated, for which the raw lidar DEM need to be smoothed. On the other hand, it is also desirable to remove those topographic depressions that do not function as closed basins at the spatial or temporal scale of the processes of interest. Setting area and depth thresholds appeared to be the preferred choice for this. We suggested using the un-autocorrelated lidar DEM error as the criterion for DEM smoothing and considering depression connections in the selection of area and depth thresholds. Using lidar data on a hummocky landscape with loamy soils in the Prairie Region of Canada, 10 to 20 times smoothing

  18. Nonsingular van der Waals potentials

    NASA Astrophysics Data System (ADS)

    Lu, J. X.; Marlow, W. H.

    1995-09-01

    Universal, spherical, nonsingular van der Waals interactions including retardation effect are developed for atoms and small molecules through a semiclassical field approach. Consideration of the finite molecular size effect removes the short-distance singular behavior inherent in the widely used potentials obtained from the point-molecule approximation. Physical arguments lead to the molecular size parameter a (in atomic units) as 1/a=1.25(I/IH)1/2, except for a system that involves at least an atom or a molecule with very different first and second ionization potentials, and for such a system the above numerical factor 1.25 is replaced by unity. Here I and IH are the first ionization potentials for the atom or molecule considered and for a hydrogen atom, respectively. The nonsingular potentials have been tested for the following representative systems: H2 (3Σ+u), He2, Ar2, NaK (3Σ+), LiHg (2Σ+), He-HF, Ne-HF, HF-HF, and Ar-HCl. Very good agreement has been found for each of the systems. Based on the above systems studied, an empirical relation has been obtained between the parameter b in the Born-Mayer repulsive potential Ae-bR and the molecular size parameters (a1 and a2). Applying this relation to dozens of systems with known b from either self-consistent-field calculations or experiments, surprisingly good agreements have been obtained. By the same token, another empirical formula is obtained that relates the van der Waals minimum well parameter Rm to the molecular size parameters (a1 and a2) and the first ionization potentials (Ix and Iy) of interacting species. Again, very good agreements have been achieved in comparison with dozens of systems with known experimental Rm's.

  19. Qualitätsmanagement in der Lebensmittelindustrie

    NASA Astrophysics Data System (ADS)

    Thorn, Volker

    Die wesentlichen Kunden der Lebensmittelindustrie sind der Einzel- und Großhandel und die Verbraucher. Jedes Unternehmen kann mittel- und langfristig nur existieren, wenn seine Kunden zufrieden sind. Kunden sind zufrieden, wenn ihre Erwartungen, die sie an Produkt, Service und Preis stellen, erfüllt werden. Also die bestimmte erwartete Qualität (Leistung) sichergestellt wird. Trotz aller Bemühungen und Anstrengungen der Anbieter, Qualitätsprodukte auf den Markt zu bringen, kames in den letzten Jahren immer wieder zu Lebensmittelskandalen.

  20. A simplified DEM-CFD approach for pebble bed reactor simulations

    SciTech Connect

    Li, Y.; Ji, W.

    2012-07-01

    In pebble bed reactors (PBR's), the pebble flow and the coolant flow are coupled with each other through coolant-pebble interactions. Approaches with different fidelities have been proposed to simulate similar phenomena. Coupled Discrete Element Method-Computational Fluid Dynamics (DEM-CFD) approaches are widely studied and applied in these problems due to its good balance between efficiency and accuracy. In this work, based on the symmetry of the PBR geometry, a simplified 3D-DEM/2D-CFD approach is proposed to speed up the DEM-CFD simulation without significant loss of accuracy. Pebble flow is simulated by a full 3-D DEM, while the coolant flow field is calculated with a 2-D CFD simulation by averaging variables along the annular direction in the cylindrical geometry. Results show that this simplification can greatly enhance the efficiency for cylindrical core, which enables further inclusion of other physics such as thermal and neutronic effect in the multi-physics simulations for PBR's. (authors)

  1. Discrete element modelling (DEM) input parameters: understanding their impact on model predictions using statistical analysis

    NASA Astrophysics Data System (ADS)

    Yan, Z.; Wilkinson, S. K.; Stitt, E. H.; Marigo, M.

    2015-09-01

    Selection or calibration of particle property input parameters is one of the key problematic aspects for the implementation of the discrete element method (DEM). In the current study, a parametric multi-level sensitivity method is employed to understand the impact of the DEM input particle properties on the bulk responses for a given simple system: discharge of particles from a flat bottom cylindrical container onto a plate. In this case study, particle properties, such as Young's modulus, friction parameters and coefficient of restitution were systematically changed in order to assess their effect on material repose angles and particle flow rate (FR). It was shown that inter-particle static friction plays a primary role in determining both final angle of repose and FR, followed by the role of inter-particle rolling friction coefficient. The particle restitution coefficient and Young's modulus were found to have insignificant impacts and were strongly cross correlated. The proposed approach provides a systematic method that can be used to show the importance of specific DEM input parameters for a given system and then potentially facilitates their selection or calibration. It is concluded that shortening the process for input parameters selection and calibration can help in the implementation of DEM.

  2. Extracting DEM from airborne X-band data based on PolInSAR

    NASA Astrophysics Data System (ADS)

    Hou, X. X.; Huang, G. M.; Zhao, Z.

    2015-06-01

    Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) is a new trend of SAR remote sensing technology which combined polarized multichannel information and Interferometric information. It is of great significance for extracting DEM in some regions with low precision of DEM such as vegetation coverage area and building concentrated area. In this paper we describe our experiments with high-resolution X-band full Polarimetric SAR data acquired by a dual-baseline interferometric airborne SAR system over an area of Danling in southern China. Pauli algorithm is used to generate the double polarimetric interferometry data, Singular Value Decomposition (SVD), Numerical Radius (NR) and Phase diversity (PD) methods are used to generate the full polarimetric interferometry data. Then we can make use of the polarimetric interferometric information to extract DEM with processing of pre filtering , image registration, image resampling, coherence optimization, multilook processing, flat-earth removal, interferogram filtering, phase unwrapping, parameter calibration, height derivation and geo-coding. The processing system named SARPlore has been exploited based on VC++ led by Chinese Academy of Surveying and Mapping. Finally compared optimization results with the single polarimetric interferometry, it has been observed that optimization ways can reduce the interferometric noise and the phase unwrapping residuals, and improve the precision of DEM. The result of full polarimetric interferometry is better than double polarimetric interferometry. Meanwhile, in different terrain, the result of full polarimetric interferometry will have a different degree of increase.

  3. Rockslide and Impulse Wave Modelling in the Vajont Reservoir by DEM-CFD Analyses

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Utili, S.; Crosta, G. B.

    2016-06-01

    This paper investigates the generation of hydrodynamic water waves due to rockslides plunging into a water reservoir. Quasi-3D DEM analyses in plane strain by a coupled DEM-CFD code are adopted to simulate the rockslide from its onset to the impact with the still water and the subsequent generation of the wave. The employed numerical tools and upscaling of hydraulic properties allow predicting a physical response in broad agreement with the observations notwithstanding the assumptions and characteristics of the adopted methods. The results obtained by the DEM-CFD coupled approach are compared to those published in the literature and those presented by Crosta et al. (Landslide spreading, impulse waves and modelling of the Vajont rockslide. Rock mechanics, 2014) in a companion paper obtained through an ALE-FEM method. Analyses performed along two cross sections are representative of the limit conditions of the eastern and western slope sectors. The max rockslide average velocity and the water wave velocity reach ca. 22 and 20 m/s, respectively. The maximum computed run up amounts to ca. 120 and 170 m for the eastern and western lobe cross sections, respectively. These values are reasonably similar to those recorded during the event (i.e. ca. 130 and 190 m, respectively). Therefore, the overall study lays out a possible DEM-CFD framework for the modelling of the generation of the hydrodynamic wave due to the impact of a rapid moving rockslide or rock-debris avalanche.

  4. The Relative Importance of Inserting TIN Topographic Breaklines in DEM Creation

    NASA Astrophysics Data System (ADS)

    Portugal, E. W.; Bangen, S. G.; Wheaton, J. M.

    2011-12-01

    The application of digital elevation models (DEM's) for geomorphic change detection and assessment of instream freshwater anadromous fish habitat has grown considerably in the last decade. Recent advances in remote sensing technologies such as LiDAR, as well as ground-based, high-resolution topographic survey equipment allow for rapid collection of high accuracy point data at a finer spatial scale than was previously available. Additionally, modern computational efficiency allows for an increased number of users to manipulate the large data sets produced from the aforementioned technologies. The post processing tools and methodologies necessary to meaningfully apply these data are increasingly recognized as vital. This work quantifies the elevational effects on DEM's of topographic breakline insertion during the editing of triangulated irregular networks (TIN's). Geomorphic change detection software including the use of a fuzzy inference system was used to compare the elevational differences between DEM's with and without the addition of breaklines. Results vary outside the active channel but from within the active channel there was a relatively small net elevational loss to both total area and volume for the breakline inserted DEM's. The significance of this net loss will continue to be explored but our current findings suggest the value of topographic breaklines to reduce elevational error in terrain model accuracy

  5. Perspective - Synthetic DEMs: A vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, John K.; Sofia, Giulia; Conway, Susan

    2015-04-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g., Earth's). A fundamental tenet of Geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Morphological data, including metrics and mapping (manual and automated), are a key resource in this endeavour. However, how good are these data that analyses rely on? Artificial or synthetic DEMs are widely used to examine the distortions of 'noise' (e.g., on topographic parameters), but only rarely to make strong 'absolute' statements about landform detection and quantification; e.g., 84% of the river channels in the real landscape are found, or 47% of all actual drumlins H > 3 m are mapped. In theory synthetic DEMs a priori containing known, idealised components can give such absolute conclusions regarding effectiveness if they can be constructed so as to represent well the actual landscapes. So, do we need good realistic synthetic DEMs, how can we best construct them, and what for? From our perspective, they are vital to verify the statistics that will link physics-driven models of processes to morphological observations, allowing quantitative hypotheses to be formulated and tested. We will outline current approaches, and some speculations about the future, but we are seeking a discussion on how best to construct realistic synthetic DEMs and proceed with uncertainty-aware landscape analysis to examine physical processes.

  6. The effect of DEM resolution on slope estimation and sediment predictions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moderate resolution (30 m) digital elevation models (DEMs) are normally used to estimate slope for the parameterization of non-point source process-based water quality models. These models, such as the Soil and Water Assessment Tool (SWAT), utilize the Modified Universal Soil Loss Equation (MUSLE) ...

  7. DEM-based Watershed Delineation - Comparison of Different Methods and applications

    NASA Astrophysics Data System (ADS)

    Chu, X.; Zhang, J.; Tahmasebi Nasab, M.

    2015-12-01

    Digital elevation models (DEMs) are commonly used for large-scale watershed hydrologic and water quality modeling. With aid of the latest LiDAR technology, submeter scale DEM data are often available for many areas in the United States. Precise characterization of the detailed variations in surface microtopography using such high-resolution DEMs is crucial to the related watershed modeling. Various methods have been developed to delineate a watershed, including determination of flow directions and accumulations, identification of subbasin boundaries, and calculation of the relevant topographic parameters. The objective of this study is to examine different DEM-based watershed delineation methods by comparing their unique features and the discrepancies in their results. Not only does this study cover the traditional watershed delineation methods, but also a new puddle-based unit (PBU) delineation method. The specific topics and issues to be presented involve flow directions (D8 single flow direction vs. multi-direction methods), segmentation of stream channels, drainage systems (single "depressionless" drainage network vs. hierarchical depression-dominated drainage system), and hydrologic connectivity (static structural connectivity vs. dynamic functional connectivity). A variety of real topographic surfaces are selected and delineated by using the selected methods. Comparisons of their delineation results emphasize the importance of selection of the methods and highlight their applicability and potential impacts on watershed modeling.

  8. Application of multi-temporal DEM data in calculating the Earth's surface deformation

    NASA Astrophysics Data System (ADS)

    Lan, Qiuping; Fei, Lifan; Liu, Yining; Zhang, Kun

    2009-10-01

    This paper suggests a method of calculating the elevation and the volume change of the terrain based on the multitemporal digital elevation model (DEM) data sets for the same area. Two methods for calculating the surface change are introduced: One is based on the regular square grids (RSG), another uses the triangulated irregular network (TIN) generalized from the original source data by the 3D Douglas-Peucker algorithm so that not only the accuracy of generalization using 3D Douglas-Peucker is verified, but also the kinds of data formats of DEM for this purpose have been expanded. Finally, the formulae used by these two methods are introduced, and the experimental results calculated from the same original DEM data acquired in 1971 and 2000 respectively form the area of Bayanbulak in Xinjiang are compared. The experiments have shown that the results of the two methods are relatively identical even if under the great generalization degree of DEM for the second method. Therefore, it shows that the second method can greatly heighten the efficiency of the calculation while insuring its accuracy.

  9. 387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; TOWERS 2, 3, 5 & 6; BRACING DETAILS - LOWER DECK; CONTRACT NO. 6; DRAWING NO. 27 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  10. 388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; SUSPENDED STRUCTURE; SIDE SPAN TRUSSES AT ANCHORAGES; CONTRACT NO. 6; DRAWING NO. 40 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  11. A problem-oriented approach for DEM data management and manipulation

    NASA Astrophysics Data System (ADS)

    Huang, Fengru; Fang, Yu; Chen, Bin

    2009-10-01

    For the last decades, GIS software technologies have made tremendous development and applied to many special fields when their targets are relevant to geographical locations. But the basis of cartographic mapping of GIS is a restriction for more development in GIS data modelling, storage and manipulation. Recently, much attention is being paid on ORDBMS(Object Relational Database Management System) to represent and manage GIS Data. New approaches have earned acceptance in many research communities and several proposals have emerged in commercial software for solving the management and manipulation on GIS vector data. Though the storage and management of field-based model data(e.g. raster, DEM, TIN) have got less achievement and people still use files and procedural ways to manipulation field-based GIS data in common applications. In this paper a new structure model using ORDBMS technology for field-based data's storage and management was proposed on the basis of full discussion on several GIS data management technologies, then a problem-oriented approach for DEM data management and manipulation was designed and implemented through open source software systems PostgreSQL and Python language. Experimental examples of different DEM data souces were stored, managed and used by using the extended spatial database system. The experiments illustrated that this solution would be a useful supplement to spatial database and it provided an effective way to DEM data management and analysis, and support the interoperability between vector data and field data.

  12. A problem-oriented approach for DEM data management and manipulation

    NASA Astrophysics Data System (ADS)

    Huang, Fengru; Fang, Yu; Chen, Bin

    2008-10-01

    For the last decades, GIS software technologies have made tremendous development and applied to many special fields when their targets are relevant to geographical locations. But the basis of cartographic mapping of GIS is a restriction for more development in GIS data modelling, storage and manipulation. Recently, much attention is being paid on ORDBMS(Object Relational Database Management System) to represent and manage GIS Data. New approaches have earned acceptance in many research communities and several proposals have emerged in commercial software for solving the management and manipulation on GIS vector data. Though the storage and management of field-based model data(e.g. raster, DEM, TIN) have got less achievement and people still use files and procedural ways to manipulation field-based GIS data in common applications. In this paper a new structure model using ORDBMS technology for field-based data's storage and management was proposed on the basis of full discussion on several GIS data management technologies, then a problem-oriented approach for DEM data management and manipulation was designed and implemented through open source software systems PostgreSQL and Python language. Experimental examples of different DEM data souces were stored, managed and used by using the extended spatial database system. The experiments illustrated that this solution would be a useful supplement to spatial database and it provided an effective way to DEM data management and analysis, and support the interoperability between vector data and field data.

  13. E-Learning an der TUM: Entwicklung - Status Quo - Perspektiven

    NASA Astrophysics Data System (ADS)

    Stross, Manfred; Baume, Matthias; Schulze, Elvira

    E-Learning an der Technischen Universität München (TUM) hat sich ähnlich wie an den meisten anderen Hochschulen als ein wesentliches Element der Hochschullehre etabliert. Seit mehr als einem Jahrzehnt werden in diesem Themenfeld Erfahrungen gesammelt und Entwicklungen vorangetrieben. Der Artikel beschäftigt sich zunächst mit E-Learning aus einer allgemeinen Perspektive und greift unterschiedliche Entwicklungsphasen der vergangenen Jahre auf. Im Anschluss daran wird der Fokus auf die TUM gesetzt. Der Beitrag zeigt die spezifische Entwicklung von E-Learning im Verlauf der vergangenen Jahre auf, nennt Funktionen und Verfahren von E-Learning und beschreibt Zielsetzungen für E-Learning an der TUM. Im Anschluss daran wird die aktuelle Situation anhand verschiedener Perspektiven analysiert. Den Abschluss des Beitrags bilden die Darstellung der zukünftigen Herausforderungen von E-Learning an der TUM und ein Ausblick auf weitere Entwicklungen.

  14. Effect of DEM resolution and comparison between different weighting factors for hydrologic connectivity index

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent; Cavalli, Marco; Degré, Aurore

    2016-04-01

    The emerging concept of hydrological connectivity is difficult to quantify. Some indices have been proposed. The most cited is Borselli's one. It mainly uses the DEM as input. The pixel size may strongly impacts the result of the calculation. It has not been studied yet in silty areas. Another important aspect is the choice of the weighting factor which strongly influences the index value. The objective of this poster is so to compare 8 different DEM's resolutions (12, 24, 48, 72, 96, 204, 504 and 996cm) and 3 different weighting factors (factor C of Wischmeier, Manning's factor and rugosity index) in the Borselli's index calculation. The IC was calculated in a 124ha catchment (Hevillers), in the loess belt, in Belgium. The DEM used is coming from a UAV with a maximum resolution of 12 cm. Permanent covered surfaces are not considered in order to avoid artefact due to the vegetation (2% of the surface). Regarding the DEM pixel size, the IC increases for a given pixel when the pixel size decreases. That confirms some results observed in the Alpine region by Cavalli (2014). The mean difference between 12 cm and 10 m resolution is 35% with higher values up to 100% for higher connectivity zones (flow paths). Another result is the lower impact of connections in the watershed (grass strips…) at lower pixel sizes. This is linked to the small width of some connections which are sometimes comparing to cell size. Furthermore, a great loss of precision is observed from the 500 cm pixel size and upper. That remark is quite intuitive. Finally, some very well disconnected zones appear for the highest resolutions. Regarding the weighting factor, IC values calculated using C factor are lower than with the rugosity index which is only a topographic factor. With very high resolution DEM, it permits to represent the fine topography. For the C factor, the zones up to very well disconnected areas (grass strips, wood…) are well represented with lower index values than downstream

  15. Comparison of Morphometry of Active Landslides in Differing Geological Settings Using LiDAR-derived DEMs

    NASA Astrophysics Data System (ADS)

    Kasai, M.; Kuda, T.; Okuda, S.; Fujisawa, K.; Asahina, T.; Matsuda, M.

    2008-12-01

    Deep seated landslides develop fine-scale geomorphic forms such as cracks and internal scars, forming rough surfaces as they move. Because the data density of LiDAR measurement is of sufficient detail to extract these forms, DEM-derived surface fabric filters can be used to estimate their recent activity. To utilize LiDAR data for this purpose, it is first necessary to establish the relationships that exist between filter values and actual surface features, and slide activities. These relationships are expected to differ between sites, reflecting the local geological and topographic characteristics, and the resolution and grid size of DEMs. In this presentation, these relationships are investigated at three study sites in Japan. The major geologies were Tertiary Tuff at two sites and sheared Mesozoic sedimentary rocks at the other. DEM cell sizes ranged from 1 to 5 m. The eigenvalue ratio, which represents the 3-dimensional surface roughness, was calculated from the DEMs. The spatial pattern of cell values within landslide blocks was compared with local surface features and slide conditions observed in the field. Results suggest that similar surface features were likely to be expressed in a higher and wider range of eigenvalue ratios as DEM grid size increased. Change in grid size, however, did not greatly alter their spatial distribution patterns. Consequently, the different major hillslope processes could be highlighted by comparing the patterns of recently active blocks from each site. In the Mesozoic sedimentary rock site, active slides contained steep slope parts which were characterized by a higher proportion of cells with an eigenvalue ratio < 2.5, when compared with surrounding areas. These low values mostly represent cracks in bedrock outcrops and scars. In contrast, the softer underlying rocks at the Tuff sites, has allowed landslides to evolve with gentle slopes, while maintaining a slow but consistent downslope motion. Here, there were a high proportion

  16. Inter-agency comparison of TanDEM-X baseline solutions

    NASA Astrophysics Data System (ADS)

    Jäggi, A.; Montenbruck, O.; Moon, Y.; Wermuth, M.; König, R.; Michalak, G.; Bock, H.; Bodenmann, D.

    2012-07-01

    TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the first Synthetic Aperture Radar (SAR) mission using close formation flying for bistatic SAR interferometry. The primary goal of the mission is to generate a global digital elevation model (DEM) with 2 m height precision and 10 m ground resolution from the configurable SAR interferometer with space baselines of a few hundred meters. As a key mission requirement for the interferometric SAR processing, the relative position, or baseline vector, of the two satellites must be determined with an accuracy of 1 mm (1D RMS) from GPS measurements collected by the onboard receivers. The operational baseline products for the TanDEM-X mission are routinely generated by the German Research Center for Geosciences (GFZ) and the German Space Operations Center (DLR/GSOC) using different software packages (EPOS/BSW, GHOST) and analysis strategies. For a further independent performance assessment, TanDEM-X baseline solutions are generated at the Astronomical Institute of the University of Bern (AIUB) on a best effort basis using the Bernese Software (BSW). Dual-frequency baseline solutions are compared for a 1-month test period in January 2011. Differences of reduced-dynamic baseline solutions exhibit a representative standard deviation (STD) of 1 mm outside maneuver periods, while biases are below 1 mm in all directions. The achieved baseline determination performance is close to the mission specification, but independent SAR calibration data takes acquired over areas with a well known DEM from previous missions will be required to fully meet the 1 mm 1D RMS target. Besides the operational solutions, single-frequency baseline solutions are tested. They benefit from a more robust ambiguity fixing and show a slightly better agreement of below 1 mm STD, but are potentially affected by errors caused by an incomplete compensation of differential ionospheric path delays.

  17. Enhancements to TauDEM to support Rapid Watershed Delineation Services

    NASA Astrophysics Data System (ADS)

    Sazib, N. S.; Tarboton, D. G.

    2015-12-01

    Watersheds are widely recognized as the basic functional unit for water resources management studies and are important for a variety of problems in hydrology, ecology, and geomorphology. Nevertheless, delineating a watershed spread across a large region is still cumbersome due to the processing burden of working with large Digital Elevation Model. Terrain Analysis Using Digital Elevation Models (TauDEM) software supports the delineation of watersheds and stream networks from within desktop Geographic Information Systems. A rich set of watershed and stream network attributes are computed. However limitations of the TauDEM desktop tools are (1) it supports only one type of raster (tiff format) data (2) requires installation of software for parallel processing, and (3) data have to be in projected coordinate system. This paper presents enhancements to TauDEM that have been developed to extend its generality and support web based watershed delineation services. The enhancements of TauDEM include (1) reading and writing raster data with the open-source geospatial data abstraction library (GDAL) not limited to the tiff data format and (2) support for both geographic and projected coordinates. To support web services for rapid watershed delineation a procedure has been developed for sub setting the domain based on sub-catchments, with preprocessed data prepared for each catchment stored. This allows the watershed delineation to function locally, while extending to the full extent of watersheds using preprocessed information. Additional capabilities of this program includes computation of average watershed properties and geomorphic and channel network variables such as drainage density, shape factor, relief ratio and stream ordering. The updated version of TauDEM increases the practical applicability of it in terms of raster data type, size and coordinate system. The watershed delineation web service functionality is useful for web based software as service deployments

  18. Entwicklung von umwelt- und naturschutzgerechten Verfahren der landwirtschaftlichen Landnutzung für das Biosphärenreservat Schorfheide-Chorin

    NASA Astrophysics Data System (ADS)

    Meyer-Aurich, Andreas

    1999-11-01

    Mit der vorliegenden Arbeit werden exemplarisch Chancen und Grenzen der Integration von Umwelt- und Naturschutz in Verfahren der ackerbaulichen Landnutzung aufgezeigt. Die Umsetzung von Zielen des Umwelt- und Naturschutzes in Verfahren der Landnutzung ist mit verschiedenen Schwierigkeiten verbunden. Diese liegen zum einen in der Konkretisierung der Ziele, um diese umsetzen zu können, zum anderen in vielfach unzulänglichem Wissen über den Zusammenhang zwischen unterschiedlichen Formen der Landnutzung und insbesondere den biotischen Naturschutzzielen. Zunächst wird die Problematik der Zielfestlegung und Konkretisierung erörtert. Das Umweltqualitätszielkonzept von Fürst et al. (1992) stellt einen Versuch dar, Ziele des Umwelt- und Naturschutzes zu konkretisieren. Dieses Konzept haben Heidt et al. (1997) auf einen Landschaftsausschnitt von ca. 6000 ha im Biosphärenreservat Schorfheide-Chorin im Nordosten Brandenburgs angewendet. Eine Auswahl der von Heidt et al. (1997) formulierten Umweltqualitätsziele bildet die Basis dieser Arbeit. Für die ausgewählten Umweltqualitätsziele wurden wesentliche Einflussfaktoren der Landnutzung identifiziert und ein Bewertungssystem entwickelt, mit dem die Auswirkungen von landwirtschaftlichen Anbauverfahren auf diese Umweltqualitätsziele abgebildet werden können. Die praktizierte Landnutzung von 20 Betrieben im Biosphärenreservat Schorfheide-Chorin wurde von 1994 bis 1997 hinsichtlich ihrer Auswirkungen auf die Umweltqualitätsziele analysiert. Die Analyse ergab ein sehr differenziertes Bild, das zum Teil Unterschiede in der Auswirkung auf die Umweltqualitätsziele für den Anbau einzelner Kulturen oder für bestimmte Betriebstypen zeigte. Es zeigte sich aber auch, dass es bei der Gestaltung des Anbaus einzelner Kulturarten große Unterschiede gab, die für Umweltqualitätsziele Bedeutung haben. Neben der Analyse der Landnutzung im Biosphärenreservat Schorfheide-Chorin wurde ein System entwickelt, mit dem die modellhafte

  19. AMES Stereo Pipeline Derived DEM Accuracy Experiment Using LROC-NAC Stereopairs and Weighted Spatial Dependence Simulation for Lunar Site Selection

    NASA Astrophysics Data System (ADS)

    Laura, J. R.; Miller, D.; Paul, M. V.

    2012-03-01

    An accuracy assessment of AMES Stereo Pipeline derived DEMs for lunar site selection using weighted spatial dependence simulation and a call for outside AMES derived DEMs to facilitate a statistical precision analysis.

  20. Genetics Home Reference: van der Woude syndrome

    MedlinePlus

    ... people with this disorder are born with a cleft lip , a cleft palate (an opening in the roof ... People with van der Woude syndrome who have cleft lip and/or palate, like other individuals with these ...

  1. Wirkungen biogener Amine auf die Erregungs-Sekretions-Kopplung in der Speicheldrüse von Periplaneta americana (L.)

    NASA Astrophysics Data System (ADS)

    Rietdorf, Katja

    2003-07-01

    habe gefunden, dass die Aktivität der Na+-K+-ATPase wichtig für die Modifikation des DA-stimulierten Primärspeichels ist. Im Gegensatz dazu ist sie für die Modifikation des 5-HT-stimulierten Primärspeichels nicht von Bedeutung. Bezüglich der Flüssigkeitssekretion habe ich keinen Einfluss der Na+-K+-ATPase-Aktivität auf die DA-stimulierten Sekretionsraten gefunden, dagegen ist die 5-HT-stimulierte Sekretionsrate in Anwesenheit von Ouabain gesteigert. Die Aktivität des NKCC ist für beide sekretorische Prozesse, die Ionen- und die Flüssigkeitssekretion, wichtig. Eine Hemmung des NKCC bewirkt eine signifikante Verringerung der Raten der Flüssigkeitssekretion nach DA- und 5-HT-Stimulierung sowie in beiden Fällen einen signifikanten Abfall der Ionenkonzentrationen im Endspeichel. Im zweiten Teil meiner Arbeit habe ich versucht, Änderungen der intrazellulären Ionenkonzentrationen in den Acinuszellen während einer DA- oder 5-HT-Stimulierung zu messen. Diese Experimente sollten mit der Methode des "ratiometric imaging" durchgeführt werden. Messungen mit dem Ca2+-sensitiven Fluoreszenzfarbstoff Fura-2 zeigten keinen globalen Anstieg in der intrazellulären Ca2+-Konzentration der P-Zellen. Aufgrund von Problemen mit einer schlechten Beladung der Zellen, einer starken und sich während der Stimulierung ändernden Autofluoreszenz der Zellen sowie Änderungen im Zellvolumen wurden keine Messungen mit Na+- und K+-sensitiven Fluoreszenzfarbstoffen durchgeführt. Im dritten Teil dieser Arbeit habe ich die intrazellulären Signalwege untersucht, die zwischen einer 5-HT-Stimulierung der Drüse und der Proteinsekretion vermitteln. Dazu wurde der Proteingehalt im Endspeichel biochemisch mittels eines modifizierten Bradford Assay gemessen. Eine erstellte Dosis-Wirkungskurve zeigt, dass die Rate der Proteinsekretion von der zur Stimulierung verwendeten 5-HT-Konzentration abhängt. In einer Serie von Experimenten habe ich die intrazellulären Konzentrationen von Ca2+, c

  2. Comparison of the SRTM DEM for the Olympic Mountains to Existing DEMs of Varying Resolutions: Results and General Implications for Application of SRTM data to Models of Hillslope and Fluvial Processes in Mountainous Regions

    NASA Astrophysics Data System (ADS)

    Montgomery, D. R.; Aalto, R.

    2001-12-01

    Predicting the spatial patterns and rates of many geomorphic processes such as hillslope erosion and down-valley sediment transport requires an accurate representation of the land surface at a scale appropriate to the particular process model. Until now, Digital Elevation Models (DEMs) throughout much of the world were of very coarse resolution (1 km) and inconsistent quality (a number of elevation sources were often quilted together to form starkly heterogeneous products). A much-anticipated solution to this problem, SRTM provides a high-resolution global DEM derived using a single instrument and standardized techniques. To explore the quality and significance of SRTM for geomorphic process models of mountainous regions, we compare the SRTM DEM to an existing suite of DEMs of varying resolutions (10 - 1,000 m) for the Olympic Mountains, Washington State. As an accessible and familiar region with prior geomorphic analysis of a wide range of DEMs of known quality, the Olympics provide an ideal locality for early application and comparison of SRTM to existing geomorphic models. We first present the similarities and differences between the three-arc-second and one-arc-second SRTM and the 100-meter and 30-meter USGS DEMs for a variety of important geomorphic parameters, including: elevation and relief, hillslope gradients, curvature, valley slope, ridge and valley volumes, and drainage area per unit contour length. We also discuss the implications of the greater SRTM resolution for modeling geomorphic processes in areas previously covered by only lower-resolution DEMs. We motivate this discussion by comparing geomorphic models for hillslope stability and wetness, as calculated with the SRTM and conventional DEMs at varying resolutions. We conclude with a summary of the benefits of SRTM and enhanced DEM resolution for modeling geomorphic processes in the Olympics, and, by extension, in other mountainous regions throughout the world.

  3. Testing DEM-based atmospheric corrections to SAR interferograms over the Los Angeles basin

    NASA Astrophysics Data System (ADS)

    Jin, L.; Funning, G. J.; Floyd, M. A.

    2009-12-01

    Atmospheric water vapor delay is the major source of noise in SAR interferograms. It is considered a prime disadvantage of high-precision InSAR technology. Without the atmospheric delay being corrected, it is hard to see any slow surface movements of the ground, e.g. fault creep; and it is impossible to validate Permanent Scatters InSAR method either, which assumes that water vapor can be estimated and removed by considering time series of interferograms. As long as the water vapor delay is estimated or measured, not only can we solve the previous two problems, but also reduce the errors in geodetic measurements, and improve the accuracy in generating Digital Elevation Models (DEMs) with ERS-1/2 tandem data. In order to reduce water vapor delay, there are some possible solutions using different data sets, including GPS, MODIS, and MERIS etc. This project is a method based on DEMs. It intends to find the relationship between topography and atmospheric water vapor delay in SAR interferograms so the water vapor signals can be reduced in interferograms. It is assumed that the atmospheric water vapor delay is linearly related to the topography over a certain distance. For example, the low phase delay appears over the places where the elevation is high; or low elevation leads to high phase delay. We tested 17 interferograms over the LA basin -- 5 from the ERS-1/2 tandem mission between 1995 and 1996; 12 from EnviSAT between 2005 and 2007 with the time spans from 35 days to 8 months. The basic idea was to divide each interferogram and DEM into a series of small windows. Then the coefficients of the relationship between the phase and the corresponding elevation in each same window were found. After interpolating these coefficients across the interferogram area, we obtained the water vapor correction by multiplying the coefficients by elevations. In this project, we tested three interpolation methods -- linear, spline, and cubic, but we found that there was little

  4. Charakterisierung von Sulfotransferasen im Gastrointestinaltrakt von Mensch und Ratte und Aktivierung von Promutagenen in V79-Zellen, die eine intestinale Form (1B1) des Menschen und der Ratte exprimieren

    NASA Astrophysics Data System (ADS)

    Teubner, Wera

    2001-05-01

    Die Ausstattung der gastrointestinalen Mukosa des Menschen und der Ratte mit Sulfotransferasen wurde mit Hilfe von Immunodetektion und Enzymaktivitätsmessungen untersucht. In Proben aus Colon und Rektum von 39 Personen wurden die Formen h1A1, h1A3 und h1B1 identifiziert, wobei in einer weiteren Probe, die als einzige von einem an Colitis Ulcerosa erkrankten Patienten stammte, keine Sulfotransferasen nachgewiesen werden konnten. Bei der Immunblot-Analyse war das Expressionsmuster der einzelnen Formen in allen Proben ähnlich. In wenigen Proben waren die relativen Signalintensitäten der h1A1 und der h1B1 um die Hälfte erniedrigt. Der Gehalt von SULT an zytosolischem Protein zeigte einen bis zu 8 - 10fachen Unterschied, er betrug jedoch bei zwei Dritteln der Proben zwischen 0,15 und 0,3 (h1A1 und h1A3) bzw. 0,6 und 0,8 Promille (h1B1). Die Variation konnte nicht auf Alter, Geschlecht oder Krankheitsbild der Patienten zurückgeführt werden. Auch der für die allelischen Varianten der h1A1 beschriebene Effekt auf die Enzymaktiviät bzw. Stabilität konnte in der Menge an immunreaktivem Protein nicht in diesem Ausma detektiert werden. Die Allelhäufigkeit von h1A1*R und h1A1*H war gegenüber der gesunden Bevölkerung nicht verändert. In den sieben Proben aus dem Dünndarm (Coecum, viermal Ileum, Jejunum) konnten zusätzlich die Formen h1E1 und h2A1 identifiziert werden. Ein möglicherweise der Form h1C1 entsprechendes Protein wurde im Magen detektiert. Im Vergleich zum Menschen war die Expression in der Ratte stärker auf die Leber konzentriert. Während beim Menschen in allen untersuchten Abschnitten Sulfotransferasen in Mengen detektiert wurden, die in zwei Fällen (h1B1 und h1A3) sogar den Gehalt in der Leber überstiegen, beschränkte sich die Expression in der Ratte auf im Vergleich zur Leber geringe Mengen im Magen und Dickdarm. Nachgewiesen wurden die r1B1, r1A1 sowie eine nicht identifizierte Form von 35kD, bei der es sich vermutlich um die r1C2 handelt. Im

  5. Effects of DEM scale on the spatial distribution of the TOPMODEL topographic wetness index and its correlations to watershed characteristics

    NASA Astrophysics Data System (ADS)

    Drover, D. R.; Jackson, C. R.; Bitew, M.; Du, E.

    2015-11-01

    Topographic wetness indices (TWIs) calculated from digital elevation models (DEMs) are meant to predict relative landscape wetness and should have predictive power for soil and vegetation attributes. While previous researchers have shown cumulative TWI distributions shift to larger values as DEM resolution decreases, there has been little work assessing how DEM scales affect TWI spatial distributions and correlations with soil and vegetation properties. We explored how various DEM resolutions (2, 5, 10, 20, 30, and 50 m) subsampled from high definition LiDAR altered the spatial distribution of TWI values and the correlations of these values with soil characteristics determined from point samples, Natural Resources Conservation Service (NRCS) soil units, depths to groundwater, and managed vegetation distributions within a first order basin in the Upper Southeastern Coastal Plain with moderate slopes, flat valleys, and several wetlands. Point-scale soil characteristics were determined by laboratory analysis of point samples collected from riparian transects and hillslope grids. DEM scale affected the spatial distribution of TWI values in ways that affect our interpretation of landscape processes. At the finest DEM resolutions, valleys disappeared as TWI values were driven by local microtopography and not basin position. Spatial distribution of TWI values most closely matched the spatial distribution of soils, depth to groundwater, and vegetation stands for the 10, 20, and 30 m resolutions. DEM resolution affected the shape and direction of relationships between soil nitrogen and carbon contents and TWI values, but TWI values provided poor prediction of soil chemistry at all resolutions.

  6. Reanalysis of the DEMS nested case-control study of lung cancer and diesel exhaust: suitability for quantitative risk assessment.

    PubMed

    Crump, Kenny S; Van Landingham, Cynthia; Moolgavkar, Suresh H; McClellan, Roger

    2015-04-01

    The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to "carcinogenic to humans." The Diesel Exhaust in Miners Study (DEMS) cohort and nested case-control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC's determination. We conducted a reanalysis of the DEMS case-control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE.

  7. Visualising DEM-related flood-map uncertainties using a disparity-distance equation algorithm

    NASA Astrophysics Data System (ADS)

    Brandt, S. Anders; Lim, Nancy J.

    2016-05-01

    The apparent absoluteness of information presented by crisp-delineated flood boundaries can lead to misconceptions among planners about the inherent uncertainties associated in generated flood maps. Even maps based on hydraulic modelling using the highest-resolution digital elevation models (DEMs), and calibrated with the most optimal Manning's roughness (n) coefficients, are susceptible to errors when compared to actual flood boundaries, specifically in flat areas. Therefore, the inaccuracies in inundation extents, brought about by the characteristics of the slope perpendicular to the flow direction of the river, have to be accounted for. Instead of using the typical Monte Carlo simulation and probabilistic methods for uncertainty quantification, an empirical-based disparity-distance equation that considers the effects of both the DEM resolution and slope was used to create prediction-uncertainty zones around the resulting inundation extents of a one-dimensional (1-D) hydraulic model. The equation was originally derived for the Eskilstuna River where flood maps, based on DEM data of different resolutions, were evaluated for the slope-disparity relationship. To assess whether the equation is applicable to another river with different characteristics, modelled inundation extents from the Testebo River were utilised and tested with the equation. By using the cross-sectional locations, water surface elevations, and DEM, uncertainty zones around the original inundation boundary line can be produced for different confidences. The results show that (1) the proposed method is useful both for estimating and directly visualising model inaccuracies caused by the combined effects of slope and DEM resolution, and (2) the DEM-related uncertainties alone do not account for the total inaccuracy of the derived flood map. Decision-makers can apply it to already existing flood maps, thereby recapitulating and re-analysing the inundation boundaries and the areas that are uncertain

  8. Methodologies for watershed modeling with GIS and DEMs for the parameterization of the WEPP model

    NASA Astrophysics Data System (ADS)

    Cochrane, Thomas Arey

    Two methods called the Hillslope and Flowpath methods were developed that use geographical information systems (GIS) and digital elevation models (DEMs) to assess water erosion in small watersheds with the Water Erosion Prediction Project (WEPP) model. The Hillslope method is an automated method for the application of WEPP through the extraction of hillslopes and channels from DEMs. Each hillslope is represented as a rectangular area with a representative slope profile that drains to the top or sides of a single channel. The Hillslope method was further divided into the Calcleng and Chanleng methods, which are similar in every way except on how the hillslope lengths are calculated. The Calcleng method calculates a representative length of hillslope based on the weighted lengths of all flowpaths in a hillslope as identified through a DEM. The Chanleng method calculates the length of hillslopes adjacent to channels by matching the width of the hillslope to the length of adjacent channel. The Flowpath method works by applying the WEPP model to all possible flowpaths within a watershed as identified from a DEM. However, this method does not currently have a channel routing component, which limits its use to predicting spatially variable erosion on hillslopes within the watershed or from watersheds whose channels are not in a depositional or erodible mode. These methods were evaluated with six research watersheds from across the U.S., one from Treynor, Iowa, two from Watkinsville, Georgia, and three from Holly Springs, Mississippi. The effects of using different-sized DEM resolutions on simulations and the ability to accurately predict sediment yield and runoff from different event sizes were studied. Statistical analyses for all methods, resolutions, and event sizes were performed by comparing predicted vs. measured runoff and sediment yield from the watershed outlets on an event by event basis. Comparisons to manual applications by expert users and comparisons of

  9. A global vegetation corrected SRTM DEM for use in hazard modelling

    NASA Astrophysics Data System (ADS)

    Bates, P. D.; O'Loughlin, F.; Neal, J. C.; Durand, M. T.; Alsdorf, D. E.; Paiva, R. C. D.

    2015-12-01

    We present the methodology and results from the development of a near-global 'bare-earth' Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM) data. Digital Elevation Models are the most important input for hazard modelling, as the DEM quality governs the accuracy of the model outputs. While SRTM is currently the best near-globally [60N to 60S] available DEM, it requires adjustments to reduce the vegetation contamination and make it useful for hazard modelling over heavily vegetated areas (e.g. tropical wetlands). Unlike previous methods of accounting for vegetation contamination, which concentrated on correcting relatively small areas and usually applied a static adjustment, we account for vegetation contamination globally and apply a spatial varying correction, based on information about canopy height and density. Our new 'Bare-Earth' SRTM DEM combines multiple remote sensing datasets, including ICESat GLA14 ground elevations, the vegetation continuous field dataset as a proxy for penetration depth of SRTM and a global vegetation height map, to remove the vegetation artefacts present in the original SRTM DEM. In creating the final 'bare-earth' SRTM DEM dataset, we produced three different 'bare-earth' SRTM products. The first applies global parameters, while the second and third products apply parameters that are regionalised based on either climatic zones or vegetation types, respectively. We also tested two different canopy density proxies of different spatial resolution. Using ground elevations obtained from the ICESat GLA14 satellite altimeter, we calculate the residual errors for the raw SRTM and the three 'bare-earth' SRTM products and compare performances. The three 'bare-earth' products all show large improvements over the raw SRTM in vegetated areas with the overall mean bias reduced by between 75 and 92% from 4.94 m to 0.40 m. The overall standard deviation is reduced by between 29 and 33 % from 7.12 m to 4.80 m. As

  10. Wie wissenschaftlich ist der Evolutionsgedanke?

    NASA Astrophysics Data System (ADS)

    Vollmer, Gerhard

    Darwin war ein besonnener Mann; alles Aufsehen war ihm zuwider. Trotzdem hat er eine Revolution ausgelöst, deren Wirkung nicht auf die Biologie beschränkt blieb. Seine Theorie lässt sich in fünf Teiltheorien zerlegen, die sich durch die Begriffe Artenwandel, Verwandtschaft alles Lebendigen und gemeinsamer Ursprung, Artenaufspaltung und Artenvielfalt, Gradualismus, natürliche Auslese charakterisieren lassen. Dadurch wurden mehrere religiöse und weitere weltanschauliche Überzeugungen in Frage gestellt. Deshalb wird die Evolutionstheorie auch heute noch vielfach kritisiert, ja bekämpft. Die Vorwürfe lassen sich ordnen nach den Kriterien, mit denen wir erfahrungswissenschaftliche Theorien beurteilen. Haltbar ist daran nur, dass es für die Evolutionstheorie zwar beliebig viele Bestätigungen gibt, aber nur wenige Widerlegungsmöglichkeiten. Durch die neuerdings entwickelten und durchgeführten Evolutionsexperimente ist die empirische Situation allerdings deutlich besser geworden. Am (erfahrungs)wissenschaftlichen Charakter der Evolutionstheorie besteht deshalb kein Zweifel.

  11. Checkpoint-Inhibitoren in der Immuntherapie: Ein Meilenstein in der Behandlung des malignen Melanoms.

    PubMed

    Wilden, Sophia M; Lang, Berenice M; Mohr, Peter; Grabbe, Stephan

    2016-07-01

    Seit Jahrzehnten ist bekannt, dass Tumoren vom Immunsystem erkannt und zerstört werden können. Diese, vor allem in Tierversuchen gewonnene Erkenntnis konnte jedoch in der Vergangenheit nicht zum Nutzen unserer Patienten umgesetzt werden, da immunonkologische Therapieansätze in den letzten Jahrzehnten in der Anwendung beim Menschen stets versagt haben. Daher hat, mit Ausnahme der adjuvanten Interferontherapie, keines dieser Verfahren den Einzug in die klinische Versorgung gefunden. Langzeitüberleben unter guter Lebensqualität war dabei sehr wenigen Patienten vorbehalten. Mit den neuen immunologischen Therapieansätzen wird jedoch sowohl das Langzeitüberleben als auch die Lebensqualität onkologischer Patienten neu definiert. Auf die neuen "Immun-Checkpoint-Inhibitoren" spricht erstmals ein relevanter Teil der behandelten Patienten an und diese zeigen in der Regel langandauernde Remissionen bis hin zur Heilung. Schon jetzt ist klar, dass die Immuntherapie in Zukunft eine der wesentlichen Therapiesäulen bei der Behandlung des metastasierten Melanoms und auch vieler anderer fortgeschrittener Tumoren bilden wird. In dieser Übersicht werden die wichtigsten neuen Therapiemodalitäten besprochen und sowohl deren Wirkprinzip als auch klinische Daten zum Therapieansprechen und zu erwartenden Nebenwirkungen der Therapie referiert. PMID:27373243

  12. A hybrid FEM-DEM approach to the simulation of fluid flow laden with many particles

    NASA Astrophysics Data System (ADS)

    Casagrande, Marcus V. S.; Alves, José L. D.; Silva, Carlos E.; Alves, Fábio T.; Elias, Renato N.; Coutinho, Alvaro L. G. A.

    2016-01-01

    In this work we address a contribution to the study of particle laden fluid flows in scales smaller than TFM (two-fluid models). The hybrid model is based on a Lagrangian-Eulerian approach. A Lagrangian description is used for the particle system employing the discrete element method (DEM), while a fixed Eulerian mesh is used for the fluid phase modeled by the finite element method (FEM). The resulting coupled DEM-FEM model is integrated in time with a subcycling scheme. The aforementioned scheme is applied in the simulation of a seabed current to analyze which mechanisms lead to the emergence of bedload transport and sediment suspension, and also quantify the effective viscosity of the seabed in comparison with the ideal no-slip wall condition. A simulation of a salt plume falling in a fluid column is performed, comparing the main characteristics of the system with an experiment.

  13. Análisis DEM 3D de arcos en regiones activas solares

    NASA Astrophysics Data System (ADS)

    Nuevo, F. A.; Mandrini, C. H.; Vásquez, A. M.; López Fuentes, M.

    2016-08-01

    The solar corona is highly organized by the magnetic field. Because of their temperature and density, magnetic loops are directly observable in active regions (ARs) in the extreme ultraviolet (EUV) and soft X-ray images. The observational determination of the three-dimensional (3D) distribution of basic physical parameters (electronic density and temperature, and magnetic field) is a fundamental constraint of coronal heating models. In this work we develop a technique of differential emission measure (DEM) analysis and we apply it an EUV loop identified in the images of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The DEM is determined after background subtraction and the electronic density and temperature in the loop are estimated from its moments. The 3D structure of the magnetic field in the loop and its intensity are modeled using linear force free field extrapolations based on AR magnetograms. In this work we show preliminary results of this technique.

  14. Coupled DEM-CFD Investigation of Granular Transport in a Fluid Channel

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Dai, F.; Xu, N. W.

    2015-09-01

    This paper presents three dimensional numerical investigations of granular transport in fluids, analysed by the Discrete Element Method (DEM) coupled with Computational Fluid Mechanics (CFD). By employing this model, the relevance of flow velocity and granular depositional morphology has been clarified. The larger the flow velocity is, the further distance the grains can be transported to. In this process, the segregation of solid grains has been clearly identified. This research reveals that coarse grains normally accumulate near the grain source region, while the fine grains can be transported to the flow front. Regardless of the different flow velocities used in these simulations, the intensity of grains segregation remains almost unchanged. The results obtained from the DEM-CFD coupled simulations can reasonably explain the grain transport process occurred in natural environments, such as river scouring, evolution of river/ocean floor, deserts and submarine landslides.

  15. The slowly varying corona from DEMs with the EVE data set

    NASA Astrophysics Data System (ADS)

    Schonfeld, Samuel J.; White, Stephen M.; Hock, Rachel A.; McAteer, James

    2016-05-01

    We present a differential emission measure (DEM) analysis of the slowly varying corona during the first half of solar cycle 24. Using the Extreme ultraviolet Variability Experiment (EVE) and the CHIANTI atomic line database we identify strong isolated iron emission lines present in the non-flaring spectrum with peak emissions covering the coronal temperature range of 5.7 < log(T) < 6.5. These lines are used to generate daily DEMs from EVE spectra to observe the long term variability of global coronal thermal properties. We discuss the choice of emission lines and the implications of this data set for the relationship between EUV and the F10.7 radio flux.

  16. DEM generation and tidal deformation detection for sulzberger ice shelf, West Antarctica using SAR interferometry

    USGS Publications Warehouse

    Baek, S.; Kwoun, Oh-Ig; Bassler, M.; Lu, Zhiming; Shum, C.K.; Dietrich, R.

    2004-01-01

    In this study we generated a relative Digital Elevation Model (DEM) over the Sulzberger Ice Shelf, West Antarctica using ERS1/2 synthetic aperture radar (SAR) interferometry data. Four repeat pass differential interferograms are used to find the grounding zone and to classify the study area. An interferometrically derived DEM is compared with laser altimetry profile from ICESat. Standard deviation of the relative height difference is 5.12 m and 1.34 m in total length of the profile and at the center of the profile respectively. The magnitude and the direction of tidal changes estimated from interferogram are compared with those predicted tidal differences from four ocean tide models. Tidal deformation measured in InSAR is -16.7 cm and it agrees well within 3 cm with predicted ones from tide models.

  17. A time series of TanDEM-X digital elevation models to monitor a glacier surge

    NASA Astrophysics Data System (ADS)

    Wendt, Anja; Mayer, Christoph; Lambrecht, Astrid; Floricioiu, Dana

    2016-04-01

    Bivachny Glacier, a tributary of the more than 70 km long Fedchenko Glacier in the Pamir Mountains, Central Asia, is a surge-type glacier with three known surges during the 20th century. In 2011, the most recent surge started which, in contrast to the previous ones, evolved down the whole glacier and reached the confluence with Fedchenko Glacier. Spatial and temporal glacier volume changes can be derived from high-resolution digital elevation models (DEMs) based on bistatic InSAR data from the TanDEM-X mission. There are nine DEMs available between 2011 and 2015 covering the entire surge period in time steps from few months up to one year. During the surge, the glacier surface elevation increased by up to 130 m in the lower part of the glacier; and change rates of up to 0.6 m per day were observed. The surface height dataset was complemented with glacier surface velocity information from TerraSAR-X/ TanDEM-X data as well as optical Landsat imagery. While the glacier was practically stagnant in 2000 after the end of the previous surge in the 1990s, the velocity increase started in 2011 in the upper reaches of the ablation area and successively moved downwards and intensified, reaching up to 4.0 m per day. The combination of surface elevation changes and glacier velocities, both of high temporal and spatial resolution, provides the unique opportunity to describe and analyse the evolution of the surge in unprecedented detail. Especially the relation between the mobilization front and the local mass transport provides insight into the surge dynamics.

  18. Disentangling conformational states of macromolecules in 3D-EM through likelihood optimization.

    PubMed

    Scheres, Sjors H W; Gao, Haixiao; Valle, Mikel; Herman, Gabor T; Eggermont, Paul P B; Frank, Joachim; Carazo, Jose-Maria

    2007-01-01

    Although three-dimensional electron microscopy (3D-EM) permits structural characterization of macromolecular assemblies in distinct functional states, the inability to classify projections from structurally heterogeneous samples has severely limited its application. We present a maximum likelihood-based classification method that does not depend on prior knowledge about the structural variability, and demonstrate its effectiveness for two macromolecular assemblies with different types of conformational variability: the Escherichia coli ribosome and Simian virus 40 (SV40) large T-antigen.

  19. a Hadoop-Based Algorithm of Generating dem Grid from Point Cloud Data

    NASA Astrophysics Data System (ADS)

    Jian, X.; Xiao, X.; Chengfang, H.; Zhizhong, Z.; Zhaohui, W.; Dengzhong, Z.

    2015-04-01

    Airborne LiDAR technology has proven to be the most powerful tools to obtain high-density, high-accuracy and significantly detailed surface information of terrain and surface objects within a short time, and from which the Digital Elevation Model of high quality can be extracted. Point cloud data generated from the pre-processed data should be classified by segmentation algorithms, so as to differ the terrain points from disorganized points, then followed by a procedure of interpolating the selected points to turn points into DEM data. The whole procedure takes a long time and huge computing resource due to high-density, that is concentrated on by a number of researches. Hadoop is a distributed system infrastructure developed by the Apache Foundation, which contains a highly fault-tolerant distributed file system (HDFS) with high transmission rate and a parallel programming model (Map/Reduce). Such a framework is appropriate for DEM generation algorithms to improve efficiency. Point cloud data of Dongting Lake acquired by Riegl LMS-Q680i laser scanner was utilized as the original data to generate DEM by a Hadoop-based algorithms implemented in Linux, then followed by another traditional procedure programmed by C++ as the comparative experiment. Then the algorithm's efficiency, coding complexity, and performance-cost ratio were discussed for the comparison. The results demonstrate that the algorithm's speed depends on size of point set and density of DEM grid, and the non-Hadoop implementation can achieve a high performance when memory is big enough, but the multiple Hadoop implementation can achieve a higher performance-cost ratio, while point set is of vast quantities on the other hand.

  20. High resolution DEM from Tandem-X interferometry: an accurate tool to characterize volcanic activity

    NASA Astrophysics Data System (ADS)

    Albino, Fabien; Kervyn, Francois

    2013-04-01

    Tandem-X mission was launched by the German agency (DLR) in June 2010. It is a new generation high resolution SAR sensor mainly dedicated to topographic applications. For the purpose of our researches focused on the study of the volcano-tectonic activity in the Kivu Rift area, a set of Tandem-X bistatic radar images were used to produce a high resolution InSAR DEM of the Virunga Volcanic Province (VVP). The VVP is part of the Western branch of the African rift, situated at the boundary between D.R. Congo, Rwanda and Uganda. It has two highly active volcanoes, Nyiragongo and Nyamulagira. A first task concerns the quantitative assessment of the vertical accuracy that can be achieved with these new data. The new DEMs are compared to other space borne datasets (SRTM, ASTER) but also to field measurements given by differential GPS. Multi-temporal radar acquisitions allow us to produce several DEM of the same area. This appeared to be very useful in the context of an active volcanic context where new geomorphological features (faults, fissures, volcanic cones and lava flows) appear continuously through time. For example, since the year 2000, time of the SRTM acquisition, we had one eruption at Nyiragongo (2002) and six eruptions at Nyamulagira (2001, 2002, 2004, 2006, 2010 and 2011) which all induce large changes in the landscape with the emplacement of new lava fields and scoria cones. From our repetitive Tandem-X DEM production, we have a tool to identify and also quantify in term of size and volume all the topographic changes relative to this past volcanic activity. These parameters are high value information to improve the understanding of the Virunga volcanoes; the accurate estimation of erupted volume and knowledge of structural features associated to past eruptions are key parameters to understand the volcanic system, to ameliorate the hazard assessment, and finally contribute to risk mitigation in a densely populated area.

  1. Aster Global dem Version 3, and New Aster Water Body Dataset

    NASA Astrophysics Data System (ADS)

    Abrams, M.

    2016-06-01

    In 2016, the US/Japan ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) project released Version 3 of the Global DEM (GDEM). This 30 m DEM covers the earth's surface from 82N to 82S, and improves on two earlier versions by correcting some artefacts and filling in areas of missing DEMs by the acquisition of additional data. The GDEM was produced by stereocorrelation of 2 million ASTER scenes and operation on a pixel-by-pixel basis: cloud screening; stacking data from overlapping scenes; removing outlier values, and averaging elevation values. As previously, the GDEM is packaged in ~ 23,000 1 x 1 degree tiles. Each tile has a DEM file, and a NUM file reporting the number of scenes used for each pixel, and identifying the source for fill-in data (where persistent clouds prevented computation of an elevation value). An additional data set was concurrently produced and released: the ASTER Water Body Dataset (AWBD). This is a 30 m raster product, which encodes every pixel as either lake, river, or ocean; thus providing a global inland and shore-line water body mask. Water was identified through spectral analysis algorithms and manual editing. This product was evaluated against the Shuttle Water Body Dataset (SWBD), and the Landsat-based Global Inland Water (GIW) product. The SWBD only covers the earth between about 60 degrees north and south, so it is not a global product. The GIW only delineates inland water bodies, and does not deal with ocean coastlines. All products are at 30 m postings.

  2. A Seamless, High-Resolution, Coastal Digital Elevation Model (DEM) for Southern California

    USGS Publications Warehouse

    Barnard, Patrick L.; Hoover, Daniel

    2010-01-01

    A seamless, 3-meter digital elevation model (DEM) was constructed for the entire Southern California coastal zone, extending 473 km from Point Conception to the Mexican border. The goal was to integrate the most recent, high-resolution datasets available (for example, Light Detection and Ranging (Lidar) topography, multibeam and single beam sonar bathymetry, and Interferometric Synthetic Aperture Radar (IfSAR) topography) into a continuous surface from at least the 20-m isobath to the 20-m elevation contour. This dataset was produced to provide critical boundary conditions (bathymetry and topography) for a modeling effort designed to predict the impacts of severe winter storms on the Southern California coast (Barnard and others, 2009). The hazards model, run in real-time or with prescribed scenarios, incorporates atmospheric information (wind and pressure fields) with a suite of state-of-the-art physical process models (tide, surge, and wave) to enable detailed prediction of water levels, run-up, wave heights, and currents. Research-grade predictions of coastal flooding, inundation, erosion, and cliff failure are also included. The DEM was constructed to define the general shape of nearshore, beach and cliff surfaces as accurately as possible, with less emphasis on the detailed variations in elevation inland of the coast and on bathymetry inside harbors. As a result this DEM should not be used for navigation purposes.

  3. A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

    2010-01-01

    As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

  4. Can Anything be Done to Improve the Geomorphological Value of off-the-Shelf DEM Products?

    NASA Astrophysics Data System (ADS)

    Milledge, D. G.; Lane, S.; Warburton, J.

    2007-12-01

    Elevation models are a fundamental requirement for distributed, process-based modelling in hydrology and geomorphology. The increased accessibility of high resolution elevation data makes them an easily accessible and potentially powerful tool in many studies. However, the quality of these data are closely linked to the processes used to derive them. These processes are rarely explicit and can be difficult to untangle. The associated errors often propagate into geomorphic variables in a highly non-linear fashion. This study examines the processes of DEM generation, the associated error and its effect on geomorphic variables in relation to modelling shallow landslide processes. Using data collected from digital photogrammetry and Airborne Interferometric Synthetic Aperture Radar (IfSAR), we show that for the same raw data, processing techniques can alter vertical precision in the elevation model by an order of magnitude. We calculate the hydrogeomorphic variables: slope, contributing area, topographic index and probability of slope instability from DEMs with different error properties to demonstrate the resulting variablilty. Based on these results we make a series of recommendations for minimising uncertainty in the DEM generation process with specific reference to airborne IfSAR and digital photogrammetry.

  5. Fusion of Laser Altimetry Data with Dems Derived from Stereo Imaging Systems

    NASA Astrophysics Data System (ADS)

    Schenk, T.; Csatho, B. M.; Duncan, K.

    2016-06-01

    During the last two decades surface elevation data have been gathered over the Greenland Ice Sheet (GrIS) from a variety of different sensors including spaceborne and airborne laser altimetry, such as NASA's Ice Cloud and land Elevation Satellite (ICESat), Airborne Topographic Mapper (ATM) and Laser Vegetation Imaging Sensor (LVIS), as well as from stereo satellite imaging systems, most notably from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Worldview. The spatio-temporal resolution, the accuracy, and the spatial coverage of all these data differ widely. For example, laser altimetry systems are much more accurate than DEMs derived by correlation from imaging systems. On the other hand, DEMs usually have a superior spatial resolution and extended spatial coverage. We present in this paper an overview of the SERAC (Surface Elevation Reconstruction And Change detection) system, designed to cope with the data complexity and the computation of elevation change histories. SERAC simultaneously determines the ice sheet surface shape and the time-series of elevation changes for surface patches whose size depends on the ruggedness of the surface and the point distribution of the sensors involved. By incorporating different sensors, SERAC is a true fusion system that generates the best plausible result (time series of elevation changes) a result that is better than the sum of its individual parts. We follow this up with an example of the Helmheim gacier, involving ICESat, ATM and LVIS laser altimetry data, together with ASTER DEMs.

  6. Dissipation consistent fabric tensor definition from DEM to continuum for granular media

    NASA Astrophysics Data System (ADS)

    Li, X. S.; Dafalias, Y. F.

    2015-05-01

    In elastoplastic soil models aimed at capturing the impact of fabric anisotropy, a necessary ingredient is a measure of anisotropic fabric in the form of an evolving tensor. While it is possible to formulate such a fabric tensor based on indirect phenomenological observations at the continuum level, it is more effective and insightful to have the tensor defined first based on direct particle level microstructural observations and subsequently deduce a corresponding continuum definition. A practical means able to provide such observations, at least in the context of fabric evolution mechanisms, is the discrete element method (DEM). Some DEM defined fabric tensors such as the one based on the statistics of interparticle contact normals have already gained widespread acceptance as a quantitative measure of fabric anisotropy among researchers of granular material behavior. On the other hand, a fabric tensor in continuum elastoplastic modeling has been treated as a tensor-valued internal variable whose evolution must be properly linked to physical dissipation. Accordingly, the adaptation of a DEM fabric tensor definition to a continuum constitutive modeling theory must be thermodynamically consistent in regards to dissipation mechanisms. The present paper addresses this issue in detail, brings up possible pitfalls if such consistency is violated and proposes remedies and guidelines for such adaptation within a recently developed Anisotropic Critical State Theory (ACST) for granular materials.

  7. Pre-2014 mudslides at Oso revealed by InSAR and multi-source DEM analysis

    NASA Astrophysics Data System (ADS)

    Kim, J. W.; Lu, Z.; QU, F.

    2014-12-01

    The landslide is a process that results in the downward and outward movement of slope-reshaping materials including rocks and soils and annually causes the loss of approximately $3.5 billion and tens of casualties in the United States. The 2014 Oso mudslide was an extreme event costing nearly 40 deaths and damaging civilian properties. Landslides are often unpredictable, but in many cases, catastrophic events are repetitive. Historic record in the Oso mudslide site indicates that there have been serial events in decades, though the extent of sliding events varied from time to time. In our study, the combination of multi-source DEMs, InSAR, and time-series InSAR analysis has enabled to characterize the Oso mudslide. InSAR results from ALOS PALSAR show that there was no significant deformation between mid-2006 and 2011. The combination of time-series InSAR analysis and old-dated DEM indicated revealed topographic changes associated the 2006 sliding event, which is confirmed by the difference of multiple LiDAR DEMs. Precipitation and discharge measurements before the 2006 and 2014 landslide events did not exhibit extremely anomalous records, suggesting the precipitation is not the controlling factor in determining the sliding events at Oso. The lack of surface deformation during 2006-2011 and weak correlation between the precipitation and the sliding event, suggest other factors (such as porosity) might play a critical role on the run-away events at this Oso and other similar landslides.

  8. Applying DEM-SRTM for reconstructing a late Quaternary paleodrainage in Amazonia

    NASA Astrophysics Data System (ADS)

    Hayakawa, Ericson H.; Rossetti, Dilce F.; Valeriano, Márcio M.

    2010-08-01

    Remote sensing is a particularly invaluable tool that has helped the detection of paleomorphologies produced by river dislocation in a variety of landscapes, which has contributed in reconstructing the geological evolution of many fluvial systems. This technique might provide useful information to discuss the evolution of large fluvial systems, in special those located in areas of difficult access where the acquisition of field data is difficult. Application of remote sensing for paleodrainage characterization in densely vegetated tropical areas is scarce in the literature. This work records processing of the Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM), which succeeded in revealing an ancient drainage complex of the Madeira River, one of the main Amazonas tributaries, where other remote sensing products failed the detection. Analysis of this paleodrainage and of its modern counterpart within the geological framework available for this region leads to propose that activity along pre-existent faults during the latest Quaternary would have promoted the southeastward dislocation of a nearly 200 km long segment of the Madeira River. During this process, an impressive paleodrainage network was left behind, which was only able to be detected using the DEM-SRTM. Application of this technique might be of great help to the detection of paleodrainage morphologies in densely vegetated areas similar to the Amazonas lowland. The dynamics of channel migration in this and many other large scale tropical river systems might benefit from the investigation based on data derived from DEM-SRTM.

  9. Newtons Wissenschaftslehre als Basis der Quantenphysik

    NASA Astrophysics Data System (ADS)

    Bopp, Fritz

    Es ist richtig zu sagen, die Quantenphysik folge nicht aus der auf Newtons Prinzipien beruhenden klassischen Physik. Es ist aber auch richtig, daß Newtons Wissenschaftslehre, die eng mit der Platonschen zusammenhängt und über diese hinausgeht, von der Quantenphysik nicht berührt wird, wie an anderer Stelle gezeigt ist. Hier wird Newtons Wissenschaftslehre genauer analysiert und der Unterschied zur kartesischen herausgearbeitet, was durch die Newtontradition verschleiert wird. Am Ende werden die Ergebnisse an Beispielen aus der Quantenoptik erläutert.Translated AbstractNewton's Epistemology as Basic Concept of Quantum PhysicsIt is correct to say that quantum physics cannot be derived from classical physics, which is founded on Newton's principles. However, it is also correct that Newton's epistemology, a more developed Platonian one, can be considered as basic for quantum physics. That is previously shown. Here, we remember Newton's epistemology more thoroughly, and consider particularly the difference to the Cartesian epistemology, a difference often veiled in the Newton tradition. Finally, we apply the result on some phenomena of quantum optics.

  10. Integrable extended van der Waals model

    NASA Astrophysics Data System (ADS)

    Giglio, Francesco; Landolfi, Giulio; Moro, Antonio

    2016-10-01

    Inspired by the recent developments in the study of the thermodynamics of van der Waals fluids via the theory of nonlinear conservation laws and the description of phase transitions in terms of classical (dissipative) shock waves, we propose a novel approach to the construction of multi-parameter generalisations of the van der Waals model. The theory of integrable nonlinear conservation laws still represents the inspiring framework. Starting from a macroscopic approach, a four parameter family of integrable extended van der Waals models is indeed constructed in such a way that the equation of state is a solution to an integrable nonlinear conservation law linearisable by a Cole-Hopf transformation. This family is further specified by the request that, in regime of high temperature, far from the critical region, the extended model reproduces asymptotically the standard van der Waals equation of state. We provide a detailed comparison of our extended model with two notable empirical models such as Peng-Robinson and Soave's modification of the Redlich-Kwong equations of state. We show that our extended van der Waals equation of state is compatible with both empirical models for a suitable choice of the free parameters and can be viewed as a master interpolating equation. The present approach also suggests that further generalisations can be obtained by including the class of dispersive and viscous-dispersive nonlinear conservation laws and could lead to a new type of thermodynamic phase transitions associated to nonclassical and dispersive shock waves.

  11. Das Lektin aus der Erbse Pisum sativum : Bindungsstudien, Monomer-Dimer-Gleichgewicht und Rückfaltung aus Fragmenten

    NASA Astrophysics Data System (ADS)

    Küster, Frank

    2002-11-01

    nicht-denaturierenden Bedingungen die Untereinheiten zwischen den Dimeren ausgetauscht werden. Die Renaturierung der unprozessierten Variante ist unter stark nativen Bedingungen zu 100 % möglich. Das prozessierte Protein dagegen renaturiert nur zu etwa 50 %, und durch die Prozessierung ist die Faltung stark verlangsamt, der Faltungsprozess ist erst nach mehreren Tagen abgeschlossen. Im Laufe der Renaturierung wird ein Intermediat populiert, in dem die längere der beiden Polypeptidketten ein Homodimer mit nativähnlicher Untereinheitenkontaktfläche bildet. Der geschwindigkeitsbestimmende Schritt der Renaturierung ist die Assoziation der entfalteten kürzeren Kette mit diesem Dimer. The lectin from Pisum sativum (garden pea) is a member of the family of legume lectins. These proteins share a high sequence homology, and the structure of their monomers, an all-ß-motif, is highly conserved. Their quaternary structures, however, show a great diversity which has been subject to cristallographic and theoretical studies. Pea lectin is a dimeric legume lectin with a special structural feature: After folding is completed in the cell, a short amino acid sequence is cut out of a loop, resulting in two independent polypeptide chains in each subunit. Both chains are closely intertwined and form one contiguous structural domain. Like all lectins, pea lectin binds to complex oligosaccharides, but its physiological role and its natural ligand are unknown. In this study, experiments to establish a functional assay for pea lectin have been conducted, and its folding, stability and monomer-dimer-equilibrium have been characterized. To investigate the specific role of the processing for stability and folding, an unprocessed construct was expressed in E. coli and compared to the processed form. Both proteins have the same kinetic stability against chemical denaturant. They denature extremely slowly, because only the isolated subunits can unfold, and the monomer-dimer-equilibrium favors

  12. Validation Of DEM Data Dvied From World View 3 Stero Imagery For Low Elevation Majuro Atoll, Marchall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a "massive" data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are nee...

  13. DEM modelling, vegetation characterization and mapping of aspen parkland rangeland using LIDAR data

    NASA Astrophysics Data System (ADS)

    Su, Guangquan

    Detailed geographic information system (GIS) studies on plant ecology, animal behavior and soil hydrologic characteristics across spatially complex landscapes require an accurate digital elevation model (DEM). Following interpolation of last return LIDAR data and creation of a LIDAR-derived DEM, a series of 260 points, stratified by vegetation type, slope gradient and off-nadir distance, were ground-truthed using a total laser station, GPS, and 27 interconnected benchmarks. Despite an overall mean accuracy of +2 cm across 8 vegetation types, it created a RMSE (square root of the mean square error) of 1.21 m. DEM elevations were over-estimated within forested areas by an average of 20 cm with a RMSE of 1.05 m, under-estimated (-12 cm, RMSE = 1.36 m) within grasslands. Vegetation type had the greatest influence on DEM accuracy, while off-nadir distance (P = 0.48) and slope gradient (P = 0.49) did not influence DEM accuracy; however, the latter factors did interact (P < 0.10) to effect accuracy. Vegetation spatial structure (i.e., physiognomy) including plant height, cover, and vertical or horizontal heterogeneity, are important factors influencing biodiversity. Vegetation over and understory were sampled for height, canopy cover, and tree or shrub density within 120 field plots, evenly stratified by vegetation formation (grassland, shrubland, and aspen forest). Results indicated that LIDAR data could be used for estimating the maximum height, cover, and density, of both closed and semi-open stands of aspen (P < 0.001). However, LIDAR data could not be used to assess understory (<1.5 m) height within aspen stands, nor grass height and cover. Recognition and mapping of vegetation types are important for rangelands as they provide a basis for the development and evaluation of management policies and actions. In this study, LIDAR data were found to be superior to digital classification schedules for their mapping accuracy in aspen forest and grassland, but not shrubland

  14. Dem Extraction from WORLDVIEW-3 Stereo-Images and Accuracy Evaluation

    NASA Astrophysics Data System (ADS)

    Hu, F.; Gao, X. M.; Li, G. Y.; Li, M.

    2016-06-01

    This paper validates the potentials of Worldview-3 satellite images in large scale topographic mapping, by choosing Worldview-3 along-track stereo-images of Yi Mountain area in Shandong province China for DEM extraction and accuracy evaluation. Firstly, eighteen accurate and evenly-distributed GPS points are collected in field and used as GCPs/check points, the image points of which are accurately measured, and also tie points are extracted from image matching; then, the RFM-based block adjustment to compensate the systematic error in image orientation is carried out and the geo-positioning accuracy is calculated and analysed; next, for the two stereo-pairs of the block, DSMs are separately constructed and mosaicked as an entirety, and also the corresponding DEM is subsequently generated; finally, compared with the selected check points from high-precision airborne LiDAR point cloud covering the same test area, the accuracy of the generated DEM with 2-meter grid spacing is evaluated by the maximum (max.), minimum (min.), mean and standard deviation (std.) values of elevation biases. It is demonstrated that, for Worldview-3 stereo-images used in our research, the planimetric accuracy without GCPs is about 2.16 m (mean error) and 0.55 (std. error), which is superior to the nominal value, while the vertical accuracy is about -1.61 m (mean error) and 0.49 m (std. error); with a small amount of GCPs located in the center and four corners of the test area, the systematic error can be well compensated. The std. value of elevation biases between the generated DEM and the 7256 LiDAR check points are about 0.62 m. If considering the potential uncertainties in the image point measurement, stereo matching and also elevation editing, the accuracy of generating DEM from Worldview-3 stereo-images should be more desirable. Judging from the results, Worldview-3 has the potential for 1:5000 or even larger scale mapping application.

  15. Creating High Quality DEMs of Large Scale Fluvial Environments Using Structure-from-Motion

    NASA Astrophysics Data System (ADS)

    Javernick, L. A.; Brasington, J.; Caruso, B. S.; Hicks, M.; Davies, T. R.

    2012-12-01

    During the past decade, advances in survey and sensor technology have generated new opportunities to investigate the structure and dynamics of fluvial systems. Key geomatic technologies include the Global Positioning System (GPS), digital photogrammetry, LiDAR, and terrestrial laser scanning (TLS). The application of such has resulted in a profound increase in the dimensionality of topographic surveys - from cross-sections to distributed 3d point clouds and digital elevation models (DEMs). Each of these technologies have been used successfully to derive high quality DEMs of fluvial environments; however, they often require specialized and expensive equipment, such as a TLS or large format camera, bespoke platforms such as survey aircraft, and consequently make data acquisition prohibitively expensive or highly labour intensive, thus restricting the extent and frequency of surveys. Recently, advances in computer vision and image analysis have led to development of a novel photogrammetric approach that is fully automated and suitable for use with simple compact (non-metric) cameras. In this paper, we evaluate a new photogrammetric method, Structure-from-Motion (SfM), and demonstrate how this can be used to generate DEMs of comparable quality to airborne LiDAR, using consumer grade cameras at low costs. Using the SfM software PhotoScan (version 0.8.5), high quality DEMs were produced for a 1.6 km reach and a 3.3 km reach of the braided Ahuriri River, New Zealand. Photographs used for DEM creation were acquired from a helicopter flying at 600 m and 800 m above ground level using a consumer grade 10.1mega-pixel, non-metric digital camera, resulting in object space resolution imagery of 0.12 m and 0.16 m respectively. Point clouds for the two study reaches were generated using 147 and 224 photographs respectively, and were extracted automatically in an arbitrary coordinate system; RTK-GPS located ground control points (GCPs) were used to define a 3d non

  16. Coastal Digital Elevation Models (DEMs) for tsunami hazard assessment on the French coasts

    NASA Astrophysics Data System (ADS)

    Maspataud, Aurélie; Biscara, Laurie; Hébert, Hélène; Schmitt, Thierry; Créach, Ronan

    2015-04-01

    Building precise and up-to-date coastal DEMs is a prerequisite for accurate modeling and forecasting of hydrodynamic processes at local scale. Marine flooding, originating from tsunamis, storm surges or waves, is one of them. Some high resolution DEMs are being generated for multiple coast configurations (gulf, embayment, strait, estuary, harbor approaches, low-lying areas…) along French Atlantic and Channel coasts. This work is undertaken within the framework of the TANDEM project (Tsunamis in the Atlantic and the English ChaNnel: Definition of the Effects through numerical Modeling) (2014-2017). DEMs boundaries were defined considering the vicinity of French civil nuclear facilities, site effects considerations and potential tsunamigenic sources. Those were identified from available historical observations. Seamless integrated topographic and bathymetric coastal DEMs will be used by institutions taking part in the study to simulate expected wave height at regional and local scale on the French coasts, for a set of defined scenarii. The main tasks were (1) the development of a new capacity of production of DEM, (2) aiming at the release of high resolution and precision digital field models referred to vertical reference frameworks, that require (3) horizontal and vertical datum conversions (all source elevation data need to be transformed to a common datum), on the basis of (4) the building of (national and/or local) conversion grids of datum relationships based on known measurements. Challenges in coastal DEMs development deal with good practices throughout model development that can help minimizing uncertainties. This is particularly true as scattered elevation data with variable density, from multiple sources (national hydrographic services, state and local government agencies, research organizations and private engineering companies) and from many different types (paper fieldsheets to be digitized, single beam echo sounder, multibeam sonar, airborne laser

  17. Coupling photogrammetric data with DFN-DEM model for rock slope hazard assessment

    NASA Astrophysics Data System (ADS)

    Donze, Frederic; Scholtes, Luc; Bonilla-Sierra, Viviana; Elmouttie, Marc

    2013-04-01

    Structural and mechanical analyses of rock mass are key components for rock slope stability assessment. The complementary use of photogrammetric techniques [Poropat, 2001] and coupled DFN-DEM models [Harthong et al., 2012] provides a methodology that can be applied to complex 3D configurations. DFN-DEM formulation [Scholtès & Donzé, 2012a,b] has been chosen for modeling since it can explicitly take into account the fracture sets. Analyses conducted in 3D can produce very complex and unintuitive failure mechanisms. Therefore, a modeling strategy must be established in order to identify the key features which control the stability. For this purpose, a realistic case is presented to show the overall methodology from the photogrammetry acquisition to the mechanical modeling. By combining Sirovision and YADE Open DEM [Kozicki & Donzé, 2008, 2009], it can be shown that even for large camera to rock slope ranges (tested about one kilometer), the accuracy of the data are sufficient to assess the role of the structures on the stability of a jointed rock slope. In this case, on site stereo pairs of 2D images were taken to create 3D surface models. Then, digital identification of structural features on the unstable block zone was processed with Sirojoint software [Sirovision, 2010]. After acquiring the numerical topography, the 3D digitalized and meshed surface was imported into the YADE Open DEM platform to define the studied rock mass as a closed (manifold) volume to define the bounding volume for numerical modeling. The discontinuities were then imported as meshed planar elliptic surfaces into the model. The model was then submitted to gravity loading. During this step, high values of cohesion were assigned to the discontinuities in order to avoid failure or block displacements triggered by inertial effects. To assess the respective role of the pre-existing discontinuities in the block stability, different configurations have been tested as well as different degree of

  18. On the COSMO-SkyMed Exploitation for Interferometric DEM Generation

    NASA Astrophysics Data System (ADS)

    Teresa, C. M.; Raffaele, N.; Oscar, N. D.; Fabio, B.

    2011-12-01

    DEM products for Earth observation space-borne applications are being to play a role of increasing importance due to the new generation of high resolution sensors (both optical and SAR). These new sensors demand elevation data for processing and, on the other hand, they provide new possibilities for DEM generation. Till now, for what concerns interferometric DEM, the Shuttle Radar Topography Mission (SRTM) has been the reference product for scientific applications all over the world. SRTM mission [1] had the challenging goal to meet the requirements for a homogeneous and reliable DEM fulfilling the DTED-2 specifications. However, new generation of high resolution sensors (including SAR) pose new requirements for elevation data in terms of vertical precision and spatial resolution. DEM are usually used as ancillary input in different processing steps as for instance geocoding and Differential SAR Interferometry. In this context, the recent SAR missions of DLR (TerraSAR-X and TanDEM-X) and ASI (COSMO-SkyMed) can play a promising role thanks to their high resolution both in space and time. In particular, the present work investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. The recent scientific works, [2] and [3], have shown the advantages of using CSK in the monitoring of terrain deformations caused by landslides, earthquakes, etc. On the other hand, thanks to the high spatial resolution, CSK appears to be very promising in monitoring man-made structures, such as buildings, bridges, railways and highways, thus enabling new potential applications (urban applications, precise DEM, etc.). We present results obtained by processing both SPOTLIGHT and STRIPMAP acquisitions through standard SAR Interferometry as well as multi-pass interferometry [4] with the aim of measuring ground elevation. Acknowledgments

  19. TÜV - Zertifizierungen in der Life Science Branche

    NASA Astrophysics Data System (ADS)

    Schaff, Peter; Gerbl-Rieger, Susanne; Kloth, Sabine; Schübel, Christian; Daxenberger, Andreas; Engler, Claus

    Life Sciences [1] (Lebenswissenschaften) sind ein globales Innovationsfeld mit Anwendungen der Bio- und Medizinwissenschaften, der Pharma-, Chemie-, Kosmetik- und Lebensmittelindustrie. Diese Branche zeichnet sich durch eine stark interdisziplinäre Ausrichtung aus, mit Anwendung wissenschaftlicher Erkenntnisse und Einsatz von Ausgangsstoffen aus der modernen Biologie, Chemie und Humanmedizin sowie gezielter marktwirtschaftlich orientierter Arbeit.

  20. Darwin, Engels und die Rolle der Arbeit in der biologischen und kulturellen Evolution des Menschen

    NASA Astrophysics Data System (ADS)

    Reichholf, Josef H.

    Im Jahre 1876, 5 Jahre nach Erscheinen von Darwins Buch über die Evolution des Menschen und die sexuelle Selektion (Darwin 1871), veröffentlichte Friedrich Engels den berühmt gewordenen Essay "Anteil der Arbeit an der Menschwerdung des Affen“ (Engels 1876). Die Kernfrage darin lautet in Kurzform: Warum hat der Mensch eigentlich ein Bedürfnis nach Arbeit? Engels Antwort wird nachfolgend näher betrachtet und vom gegenwärtigen Kenntnisstand aus beurteilt. Wie sich zeigen wird, beantworten seine Überlegungen die Frage nicht wirklich. Sie ist weiterhin offen. Es können lediglich einige zusätzliche Anhaltspunkte zur Diskussion gestellt werden. Angesichts des drängenden Problems millionenfacher Arbeitslosigkeit und der Forderungen nach einem "Grundrecht auf Arbeit“ kommt den Überlegungen zum möglichen Ursprung des Bedürfnisses nach Arbeit mehr als nur akademisches Interesse zu.

  1. Ben van der Veken Honor Issue

    NASA Astrophysics Data System (ADS)

    Durig, James

    2015-02-01

    In acclamation of Ben van der Veken, a former editor of Spectrochimica Acta, many co-authors and friends have submitted papers in his honor. He has collaborated with many scientists from the United States, Russia, England, Scotland as well as some in other countries. His research is known throughout the world.

  2. Auf der Suche nach extrasolaren Transitplaneten

    NASA Astrophysics Data System (ADS)

    Heller, René

    2010-06-01

    Planeten um andere Sonnen, die von der Erde aus gesehen einmal während ihres Orbits vor ihrem Zentralstern vorbeiziehen, eröffnen eine bis vor Kurzem ungeahnte Palette an Möglichkeiten zu ihrer Untersuchung. Nur: Wo am Himmel lassen sich diese Kandidaten für Sternbedeckungen eigentlich finden?

  3. Note on a van der Waals Gas.

    ERIC Educational Resources Information Center

    Bauman, Robert P.; Harrison, Joseph G.

    1996-01-01

    Discusses the difficulties with the standard model for introduction of attractive forces into the van der Waals equation. Presents an analysis in terms of force and time delays and an alternative analysis for more advanced students in terms of energy. (JRH)

  4. The Forced van der Pol Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2009-01-01

    We report on a study of the forced van der Pol equation x + [epsilon](x[superscript 2] - 1)x + x = F cos[omega]t, by solving numerically the differential equation for a variety of values of the parameters [epsilon], F and [omega]. In doing so, many striking and interesting trajectories can be discovered and phenomena such as frequency entrainment,…

  5. Obituary for Jan van der Pers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    After a short but valiant struggle against cancer, Jan van der Pers died on 29 April, 2006 in the hospital in Hilversum, The Netherlands, close to his home. Our conversations with Jan during the last months of his life showed the remarkable strength and positive attitude typical of him. Discussions...

  6. Computer vision: automating DEM generation of active lava flows and domes from photos

    NASA Astrophysics Data System (ADS)

    James, M. R.; Varley, N. R.; Tuffen, H.

    2012-12-01

    Accurate digital elevation models (DEMs) form fundamental data for assessing many volcanic processes. We present a photo-based approach developed within the computer vision community to produce DEMs from a consumer-grade digital camera and freely available software. Two case studies, based on the Volcán de Colima lava dome and the Puyehue Cordón-Caulle obsidian flow, highlight the advantages of the technique in terms of the minimal expertise required, the speed of data acquisition and the automated processing involved. The reconstruction procedure combines structure-from-motion and multi-view stereo algorithms (SfM-MVS) and can generate dense 3D point clouds (millions of points) from multiple photographs of a scene taken from different positions. Processing is carried out by automated software (e.g. http://blog.neonascent.net/archives/bundler-photogrammetry-package/). SfM-MVS reconstructions are initally un-scaled and un-oriented so additional geo-referencing software has been developed. Although this step requires the presence of some control points, the SfM-MVS approach has significantly easier image acquisition and control requirements than traditional photogrammetry, facilitating its use in a broad range of difficult environments. At Colima, the lava dome surface was reconstructed from recent and archive images taken from light aircraft over flights (2007-2011). Scaling and geo-referencing was carried out using features identified in web-sourced ortho-imagery obtained as a basemap layer in ArcMap - no ground-based measurements were required. Average surface measurement densities are typically 10-40 points per m2. Over mean viewing distances of ~500-2500 m (for different surveys), RMS error on the control features is ~1.5 m. The derived DEMs (with 1-m grid resolution) are sufficient to quantify volumetric change, as well as to highlight the structural evolution of the upper surface of the dome following an explosion in June 2011. At Puyehue Cord

  7. Analysis and Validation of Grid dem Generation Based on Gaussian Markov Random Field

    NASA Astrophysics Data System (ADS)

    Aguilar, F. J.; Aguilar, M. A.; Blanco, J. L.; Nemmaoui, A.; García Lorca, A. M.

    2016-06-01

    Digital Elevation Models (DEMs) are considered as one of the most relevant geospatial data to carry out land-cover and land-use classification. This work deals with the application of a mathematical framework based on a Gaussian Markov Random Field (GMRF) to interpolate grid DEMs from scattered elevation data. The performance of the GMRF interpolation model was tested on a set of LiDAR data (0.87 points/m2) provided by the Spanish Government (PNOA Programme) over a complex working area mainly covered by greenhouses in Almería, Spain. The original LiDAR data was decimated by randomly removing different fractions of the original points (from 10% to up to 99% of points removed). In every case, the remaining points (scattered observed points) were used to obtain a 1 m grid spacing GMRF-interpolated Digital Surface Model (DSM) whose accuracy was assessed by means of the set of previously extracted checkpoints. The GMRF accuracy results were compared with those provided by the widely known Triangulation with Linear Interpolation (TLI). Finally, the GMRF method was applied to a real-world case consisting of filling the LiDAR-derived DSM gaps after manually filtering out non-ground points to obtain a Digital Terrain Model (DTM). Regarding accuracy, both GMRF and TLI produced visually pleasing and similar results in terms of vertical accuracy. As an added bonus, the GMRF mathematical framework makes possible to both retrieve the estimated uncertainty for every interpolated elevation point (the DEM uncertainty) and include break lines or terrain discontinuities between adjacent cells to produce higher quality DTMs.

  8. ArcticDEM; A Publically Available, High Resolution Elevation Model of the Arctic

    NASA Astrophysics Data System (ADS)

    Morin, Paul; Porter, Claire; Cloutier, Michael; Howat, Ian; Noh, Myoung-Jong; Willis, Michael; Bates, Brian; Willamson, Cathleen; Peterman, Kennith

    2016-04-01

    A Digital Elevation Model (DEM) of the Arctic is needed for a large number of reasons, including: measuring and understanding rapid, ongoing changes to the Arctic landscape resulting from climate change and human use and mitigation and adaptation planning for Arctic communities. The topography of the Arctic is more poorly mapped than most other regions of Earth due to logistical costs and the limits of satellite missions with low-latitude inclinations. A convergence of civilian, high-quality sub-meter stereo imagery; petascale computing and open source photogrammetry software has made it possible to produce a complete, very high resolution (2 to 8-meter posting), elevation model of the Arctic. A partnership between the US National Geospatial-intelligence Agency and a team led by the US National Science Foundation funded Polar Geospatial Center is using stereo imagery from DigitalGlobe's Worldview-1, 2 and 3 satellites and the Ohio State University's Surface Extraction with TIN-based Search-space Minimization (SETSM) software running on the University of Illinois's Blue Water supercomputer to address this challenge. The final product will be a seemless, 2-m posting digital surface model mosaic of the entire Arctic above 60 North including all of Alaska, Greenland and Kamchatka. We will also make available the more than 300,000 individual time-stamped DSM strip pairs that were used to assemble the mosaic. The Arctic DEM will have a vertical precision of better than 0.5m and can be used to examine changes in land surfaces such as those caused by permafrost degradation or the evolution of arctic rivers and floodplains. The data set can also be used to highlight changing geomorphology due to Earth surface mass transport processes occurring in active volcanic and glacial environments. When complete the ArcticDEM will catapult the Arctic from the worst to among the best mapped regions on Earth.

  9. High mobility of large mass movements: a study by means of FEM/DEM simulations

    NASA Astrophysics Data System (ADS)

    Manzella, I.; Lisjak, A.; Grasselli, G.

    2013-12-01

    Large mass movements, such as rock avalanches and large volcanic debris avalanches are characterized by extremely long propagation, which cannot be modelled using normal sliding friction law. For this reason several studies and theories derived from field observation, physical theories and laboratory experiments, exist to try to explain their high mobility. In order to investigate more into deep some of the processes recalled by these theories, simulations have been run with a new numerical tool called Y-GUI based on the Finite Element-Discrete Element Method FEM/DEM. The FEM/DEM method is a numerical technique developed by Munjiza et al. (1995) where Discrete Element Method (DEM) algorithms are used to model the interaction between different solids, while Finite Element Method (FEM) principles are used to analyze their deformability being also able to explicitly simulate material sudden loss of cohesion (i.e. brittle failure). In particular numerical tests have been run, inspired by the small-scale experiments done by Manzella and Labiouse (2013). They consist of rectangular blocks released on a slope; each block is a rectangular discrete element made of a mesh of finite elements enabled to fragment. These simulations have highlighted the influence on the propagation of block packing, i.e. whether the elements are piled into geometrical ordinate structure before failure or they are chaotically disposed as a loose material, and of the topography, i.e. whether the slope break is smooth and regular or not. In addition the effect of fracturing, i.e. fragmentation, on the total runout have been studied and highlighted.

  10. Development and Evaluation of Simple Measurement System Using the Oblique Photo and dem

    NASA Astrophysics Data System (ADS)

    Nonaka, H.; Sasaki, H.; Fujimaki, S.; Naruke, S.; Kishimoto, H.

    2016-06-01

    When a disaster occurs, we must grasp and evaluate its damage as soon as possible. Then we try to estimate them from some kind of photographs, such as surveillance camera imagery, satellite imagery, photographs taken from a helicopter and so on. Especially in initial stage, estimation of decent damage situation for a short time is more important than investigation of damage situation for a long time. One of the source of damage situation is the image taken by surveillance camera, satellite sensor and helicopter. If we can measure any targets in these imagery, we can estimate a length of a lava flow, a reach of a cinder and a sediment volume in volcanic eruption or landslide. Therefore in order to measure various information for a short time, we developed a simplified measurement system which uses these photographs. This system requires DEM in addition to photographs, but it is possible to use previously acquired DEM. To measure an object, we require only two steps. One is the determination of the position and the posture in which the photograph is shot. We determine these parameters using DEM. The other step is the measurement of an object in photograph. In this paper, we describe this system and show the experimental results to evaluate this system. In this experiment we measured the top of Mt. Usu by using two measurement method of this system. Then we can measure it about one hour and the difference between the measurement results and the airborne LiDAR data are less than 10 meter.

  11. A detailed observation of a LMC supernova remnant DEM L241 with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bamba, A.; Ueno, M.; Nakajima, H.; Mori, K.; Koyama, K.

    2006-05-01

    We report on an XMM-Newton observation of the supernova remnant (SNR) DEM L241 in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish, with a central compact source. The compact source is point-like, and named XMMU J053559.3-673509. The source spectrum is reproduced well by a power-law model with a photon index of Γ = 1.57 (1.51-1.62); and the intrinsic luminosity is 2.2 × 1035~erg~s-1 in the 0.5-10.0 keV band, with an assumed distance of 50 kpc. The source has neither significant coherent pulsations in 2.0 × 10-3-8.0 Hz nor time variabilities. Its luminosity and spectrum suggest that the source might be a pulsar wind nebula (PWN) in DEM L241. The spectral feature classifies this source as rather bright and hard PWN, which is similar to those in Kes 75 and B0540-693. The elongated diffuse structure can be divided into a "Head" and "Tail", and both have soft and line-rich spectra. Their spectra are reproduced well by a plane-parallel shock plasma (vpshock) model with a temperature of 0.3-0.4 keV, over-abundance in O and Ne, and a relative under-abundance in Fe. Such an abundance pattern and the morphology imply both that the emission is from the ejecta of the SNR and that the progenitor of DEM L241 is a very massive star, more than 20 M_⊙. This result is also supported by the existence of the central point source and an OB star association, LH 88. The total thermal energy and plasma mass are ~4 × 1050 erg and ~200~M_⊙, respectively.

  12. Sensitivity of watershed attributes to spatial resolution and interpolation method of LiDAR DEMs in three distinct landscapes

    NASA Astrophysics Data System (ADS)

    Goulden, T.; Hopkinson, C.; Jamieson, R.; Sterling, S.

    2014-03-01

    This study investigates scaling relationships of watershed area and stream networks delineated from LiDAR DEMs. The delineations are tested against spatial resolution, including 1, 5, 10, 25, and 50 m, and interpolation method, including Inverse Distance Weighting (IDW), Moving Average (MA), Universal Kriging (UK), Natural Neighbor (NN), and Triangular Irregular Networks (TIN). Study sites include Mosquito Creek, Scotty Creek, and Thomas Brook, representing landscapes with high, low, and moderate change in elevation, respectively. Results show scale-dependent irregularities in watershed area due to spatial resolution at Thomas Brook and Mosquito Creek. The highest sensitivity of watershed area to spatial resolution occurred at Scotty Creek, due to high incidence of LiDAR sensor measurement error and subtle changes in elevation. Length of drainage networks did not show a scaling relationship with spatial resolution, due to algorithmic complications of the stream initiation threshold. Stream lengths of main channels at Thomas Brook and Mosquito Creek displayed systematic increases in length with increasing spatial resolution, described through an average fractal dimension of 1.059. The scaling relationship between stream length and DEM resolution allows estimation of stream lengths from low-resolution DEMs in the absence of high-resolution DEMs. Single stream validation at Thomas Brook showed the 1 m DEM produced the lowest length error and highest spatial accuracy, at 3.7% and 71.3%, respectively. Single stream validation at Mosquito Creek showed the 25 m DEM produced the lowest length error, and the 1 m DEM the highest spatial accuracy, at 0.6% and 61.0%, respectively.

  13. Reanalysis of the DEMS Nested Case-Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment

    PubMed Central

    Crump, Kenny S; Van Landingham, Cynthia; Moolgavkar, Suresh H; McClellan, Roger

    2015-01-01

    The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case-control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC’s determination. We conducted a reanalysis of the DEMS case-control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE. PMID:25857246

  14. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    SciTech Connect

    Seward, F. D.; Charles, P. A.; Foster, D. L.; Dickel, J. R.; Romero, P. S.; Edwards, Z. I.; Perry, M.; Williams, R. M.

    2012-11-10

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

  15. Temporal monitoring of Bardarbunga volcanic activity with TanDEM-X

    NASA Astrophysics Data System (ADS)

    Rossi, C.; Minet, C.; Fritz, T.; Eineder, M.; Erten, E.

    2015-12-01

    On August 29, 2014, a volcanic activity started in the lava field of Holuhraun, at the north east of the Bardarbunga caldera in Iceland. The activity was declared finished on February 27, 2015, thus lasting for about 6 months. During these months the magma chamber below the caldera slowly emptied, causing the rare event of caldera collapse. In this scenario, TanDEM-X remote sensing data is of particular interest. By producing high-resolution and accurate elevation models of the caldera, it is possible to evaluate volume losses and topographical changes useful to increase the knowledge about the volcanic activity dynamics. 5 TanDEM-X InSAR acquisitions have been commanded between August 01, 2014 and November 08, 2014. 2 acquisitions have been commanded before the eruption and 3 acquisitions afterwards. To fully cover the volcanic activity, also the lava flow area at the north-west of the caldera has been monitored and a couple of acquisitions have been employed to reveal the subglacial graben structure and the lava path. In this context, the expected elevation accuracy is studied on two levels. Absolute height accuracy is analyzed by inspecting the signal propagation at X-band in the imaged medium. Relative height accuracy is analyzed by investigating the InSAR system parameters and the local geomorphology. It is shown how the system is very well accurate with mean height errors below the meter. Moreover, neither InSAR processing issues, e.g. phase unwrapping errors, nor complex DEM calibration aspects are problems to tackle. Caldera is imaged in its entirety and new cauldron formations and, in general, the complete restructuring of the glacial volcanic system is well represented. An impressive caldera volume loss of about 1 billion cubic meters is measured in about two months. The dyke propagation from the Bardarbunga cauldron to the Holuhraun lava field is also revealed and a graben structure with a width of up to 1 km and a sinking of a few meters is derived

  16. A 3D DEM-LBM approach for the assessment of the quick condition for sands

    NASA Astrophysics Data System (ADS)

    Mansouri, M.; Delenne, J.-Y.; El Youssoufi, M. S.; Seridi, A.

    2009-09-01

    We present a 3D numerical model to assess the quick condition (the onset of the boiling phenomenon) in a saturated polydisperse granular material. We use the Discrete Element Method (DEM) to study the evolution of the vertical intergranular stress in a granular sample subjected to an increasing hydraulic gradient. The hydrodynamic forces on the grains of the sample are computed using the Lattice Boltzmann Method (LBM). The principal assumption used is that grains remain at rest until the boiling onset. We show that the obtained critical hydraulic gradient is close to that defined in classical soil mechanics. To cite this article: M. Mansouri et al., C. R. Mecanique 337 (2009).

  17. Evaluation of TanDEM-X elevation data for geomorphological mapping and interpretation in high mountain environments - A case study from SE Tibet, China

    NASA Astrophysics Data System (ADS)

    Pipaud, Isabel; Loibl, David; Lehmkuhl, Frank

    2015-10-01

    Digital elevation models (DEMs) are a prerequisite for many different applications in the field of geomorphology. In this context, the two near-global medium resolution DEMs originating from the SRTM and ASTER missions are widely used. For detailed geomorphological studies, particularly in high mountain environments, these datasets are, however, known to have substantial disadvantages beyond their posting, i.e., data gaps and miscellaneous artifacts. The upcoming TanDEM-X DEM is a promising candidate to improve this situation by application of state-of-the-art radar technology, exhibiting a posting of 12 m and less proneness to errors. In this study, we present a DEM processed from a single TanDEM-X CoSSC scene, covering a study area in the extreme relief of the eastern Nyainqêntanglha Range, southeastern Tibet. The potential of the resulting experimental TanDEM-X DEM for geomorphological applications was evaluated by geomorphometric analyses and an assessment of landform cognoscibility and artifacts in comparison to the ASTER GDEM and the recently released SRTM 1″ DEM. Detailed geomorphological mapping was conducted for four selected core study areas in a manual approach, based exclusively on the TanDEM-X DEM and its basic derivates. The results show that the self-processed TanDEM-X DEM yields a detailed and widely consistent landscape representation. It thus fosters geomorphological analysis by visual and quantitative means, allowing delineation of landforms down to footprints of ~ 30 m. Even in this premature state, the TanDEM-X elevation data are widely superior to the ASTER and SRTM datasets, primarily owing to its significantly higher resolution and its lower susceptibility to artifacts that hamper landform interpretation. Conversely, challenges toward interferometric DEM generation were identified, including (i) triangulation facets and missing topographic information resulting from radar layover on steep slopes facing toward the radar sensor, (ii) low

  18. Finding the service you need: human centered design of a Digital Interactive Social Chart in DEMentia care (DEM-DISC).

    PubMed

    van der Roest, H G; Meiland, F J M; Haaker, T; Reitsma, E; Wils, H; Jonker, C; Dröes, R M

    2008-01-01

    Community dwelling people with dementia and their informal carers experience a lot of problems. In the course of the disease process people with dementia become more dependent on others and professional help is often necessary. Many informal carers and people with dementia experience unmet needs with regard to information on the disease and on the available care and welfare offer, therefore they tend not to utilize the broad spectrum of available care and welfare services. This can have very negative consequences like unsafe situations, social isolation of the person with dementia and overburden of informal carers with consequent increased risk of illness for them. The development of a DEMentia specific Digital Interactive Social Chart (DEM-DISC) may counteract these problems. DEM-DISC is a demand oriented website for people with dementia and their carers, which is easy, accessible and provides users with customized information on healthcare and welfare services. DEM-DISC is developed according to the human centered design principles, this means that people with dementia, informal carers and healthcare professionals were involved throughout the development process. This paper describes the development of DEM-DISC from four perspectives, a domain specific content perspective, an ICT perspective, a user perspective and an organizational perspective. The aims and most important results from each perspective will be discussed. It is concluded that the human centered design was a valuable method for the development of the DEM-DISC.

  19. GEOEYE-1 Satellite Stereo-Pair DEM Extraction Using Scale-Invariant Feature Transform on a Parallel Processing Platform

    NASA Astrophysics Data System (ADS)

    Daliakopoulos, Ioannis; Tsanis, Ioannis

    2013-04-01

    A module for Digital Elevation Model (DEM) extraction from Very High Resolution (VHR) satellite stereo-pair imagery was developed. A procedure for parallel processing of cascading image tiles is used for handling the large datasets requirements of VHR satellite imagery. The Scale-Invariant Feature Transform (SIFT) algorithm is used to detect potentially homogeneous features in the members of the stereo-pair. The resulting feature pairs are filtered using the RANdom SAmple Consensus (RANSAC) algorithm by using a variable distance threshold. Finally, homogeneous pairs are converted to point cloud ground coordinates for DEM generation. The module is tested with a 0.5mx0.5m Geoeye-1 stereo-pair acquired over an area of 25sqkm in the island of Crete, Greece. A sensitivity analysis is performed to determine the optimum module parameterization. The criteria of average point spacing irregularity is introduced to evaluate the quality and assess the effective resolution of the produced DEMs. The resulting 1.5mx1.5m DEM has superior detail over the 2m and 5m DEMs used as reference and yields a Root Mean Square Error (RMSE) of about 1m compared to ground truth measurements.

  20. Visualizing impact structures using high-resolution LiDAR-derived DEMs: A case study of two structures in Missouri

    USGS Publications Warehouse

    Finn, Michael P.; Krizanich, Gary W.; Evans, Kevin R.; Cox, Melissa R.; Yamamoto, Kristina H.

    2015-01-01

    Evidence suggests that a crypto-explosive hypothesis and a meteorite impact hypothesis may be partly correct in explaining several anomalous geological features in the middle of the United States. We used a primary geographic information science (GIScience) technique of creating a digital elevation model (DEM) of two of these features that occur in Missouri. The DEMs were derived from airborne light detection and ranging, or LiDAR. Using these DEMs, we characterized the Crooked Creek structure in southern Crawford County and the Weaubleau structure in southeastern St. Clair County, Missouri. The mensuration and study of exposed and buried impact craters implies that the craters may have intrinsic dimensions which could only be produced by collision. The results show elevations varying between 276 and 348 m for Crooked Creek and between 220 and 290 m for Weaubleau structure. These new high- resolution DEMs are accurate enough to allow for precise measurements and better interpretations of geological structures, particularly jointing in the carbonate rocks, and they show greater definition of the central uplift area in the Weaubleau structure than publicly available DEMs.

  1. Development of high-resolution coastal DEMs: Seamlessly integrating bathymetric and topographic data to support coastal inundation modeling

    NASA Astrophysics Data System (ADS)

    Eakins, B. W.; Taylor, L. A.; Warnken, R. R.; Carignan, K. S.; Sharman, G. F.

    2006-12-01

    The National Geophysical Data Center (NGDC), an office of the National Oceanic and Atmospheric Administration (NOAA), is cooperating with the NOAA Pacific Marine Environmental Laboratory (PMEL), Center for Tsunami Research to develop high-resolution digital elevation models (DEMs) of combined bathymetry and topography. The coastal DEMs will be used as input for the Method of Splitting Tsunami (MOST) model developed by PMEL to simulate tsunami generation, propagation and inundation. The DEMs will also be useful in studies of coastal inundation caused by hurricane storm surge and rainfall flooding, resulting in valuable information for local planners involved in disaster preparedness. We present our methodology for creating the high-resolution coastal DEMs, typically at 1/3 arc-second (10 meters) cell size, from diverse digital datasets collected by numerous methods, in different terrestrial environments, and at various scales and resolutions; one important step is establishing the relationships between various tidal and geodetic vertical datums, which may vary over a gridding region. We also discuss problems encountered and lessons learned, using the Myrtle Beach, South Carolina DEM as an example.

  2. Application of the PROMETHEE technique to determine depression outlet location and flow direction in DEM

    NASA Astrophysics Data System (ADS)

    Chou, Tien-Yin; Lin, Wen-Tzu; Lin, Chao-Yuan; Chou, Wen-Chieh; Huang, Pi-Hui

    2004-02-01

    With the fast growing progress of computer technologies, spatial information on watersheds such as flow direction, watershed boundaries and the drainage network can be automatically calculated or extracted from a digital elevation model (DEM). The stubborn problem that depressions exist in DEMs has been frequently encountered while extracting the spatial information of terrain. Several filling-up methods have been proposed for solving depressions. However, their suitability for large-scale flat areas is inadequate. This study proposes a depression watershed method coupled with the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEEs) theory to determine the optimal outlet and calculate the flow direction in depressions. Three processing procedures are used to derive the depressionless flow direction: (1) calculating the incipient flow direction; (2) establishing the depression watershed by tracing the upstream drainage area and determining the depression outlet using PROMETHEE theory; (3) calculating the depressionless flow direction. The developed method was used to delineate the Shihmen Reservoir watershed located in Northern Taiwan. The results show that the depression watershed method can effectively solve the shortcomings such as depression outlet differentiating and looped flow direction between depressions. The suitability of the proposed approach was verified.

  3. Investigating sediment budgets and pathways using LiDAR DEMs of difference and a geomorphological map

    NASA Astrophysics Data System (ADS)

    Hilger, Ludwig; Becht, Michael; Heckmann, Tobias

    2014-05-01

    In alpine catchments sediment is moved from one landform to another as long as they are coupled by the activity of geomorphic processes. The spatial and functional interaction of these processes forms sediment cascades reaching from sediment sources or stores to sediment sinks, and ultimately to the catchment outlet. In study presented here, multitemporal high-resolution LiDAR datasets are used to establish morphological sediment budgets. These can be calculated on the raster cell scale, i.e. by differencing digital elevation models (DEM), and on the landform scale, by establishing the net balance of eroded and accumulated material; in the latter case, the spatial unit is a polygon identifying a particular landform on a detailed geomorphological map. The flow of mobilised sediment can be estimated on a DEM using a variety of flow routing algorithms, and the net balance (sediment eroded - sediment deposited) is accumulated along specific pathways. The results of landform-based sediment budgets can be used to validate the flow routing algorithms and to assess functional connectivity between landforms that are arranged along a toposequence. Graph theory is used to store and investigate resulting sediment pathways on different aggregation levels. The incorporation of the geomorphological map highlights potential advantages of object-based over pixel-based approaches to generating graph nodes and analysing sediment cascades.

  4. Rapid visualization of global image and dem based on SDOG-ESSG

    NASA Astrophysics Data System (ADS)

    Bo, H. G.; Wu, L. X.; Yu, J. Q.; Yang, Y. Z.; Xie, L.

    2013-10-01

    Due to the limit of the two-dimension and small scale issues, it's impossible for the conventional planar and spherical global spatial grid to provide a unified real three-dimensional (3D) data model for Earth System Science research. The surface of the Earth is an important interface between lithosphere and atmosphere. Usually, the terrain should be added into the model in global changes and tectonic plates movement researches. However, both atmosphere and lithosphere are typical objects of three-dimension. Thus, it is necessary to represent and visualize the terrain in a real 3D mode. Spheroid Degenerated Octree Grid based Earth System Spatial Grid (SDOG-ESSG) not only solve the problem small-scale issues limited, but also solve the problem of two-dimension issues oriented. It can be used as real 3D model to represent and visualize the global image and DEM. Owing to the complex spatial structure of SDOG-ESSG, the visual efficiency of spatial data based on SDOG-ESSG is very low. Methods of layers and blocks data organization, as well as data culling, Level of Detail (LOD), and asynchronous scheduling, were adopted in this article to improve the efficiency of visualization. Finally, a prototype was developed for the quick visualization of global DEM and image based SDOG-ESSG.

  5. Kinematic behaviour of a large earthflow defined by surface displacement monitoring, DEM differencing, and ERT imaging

    NASA Astrophysics Data System (ADS)

    Prokešová, Roberta; Kardoš, Miroslav; Tábořík, Petr; Medveďová, Alžbeta; Stacke, Václav; Chudý, František

    2014-11-01

    Large earthflow-type landslides are destructive mass movement phenomena with highly unpredictable behaviour. Knowledge of earthflow kinematics is essential for understanding the mechanisms that control its movements. The present paper characterises the kinematic behaviour of a large earthflow near the village of Ľubietová in Central Slovakia over a period of 35 years following its most recent reactivation in 1977. For this purpose, multi-temporal spatial data acquired by point-based in-situ monitoring and optical remote sensing methods have been used. Quantitative data analyses including strain modelling and DEM differencing techniques have enabled us to: (i) calculate the annual landslide movement rates; (ii) detect the trend of surface displacements; (iii) characterise spatial variability of movement rates; (iv) measure changes in the surface topography on a decadal scale; and (v) define areas with distinct kinematic behaviour. The results also integrate the qualitative characteristics of surface topography, in particular the distribution of surface structures as defined by a high-resolution DEM, and the landslide subsurface structure, as revealed by 2D resistivity imaging. Then, the ground surface kinematics of the landslide is evaluated with respect to the specific conditions encountered in the study area including slope morphology, landslide subsurface structure, and local geological and hydrometeorological conditions. Finally, the broader implications of the presented research are discussed with particular focus on the role that strain-related structures play in landslide kinematic behaviour.

  6. Open-source MFIX-DEM software for gas-solids flows: Part II Validation studies

    SciTech Connect

    Li, Tingwen; Garg, Rahul; Galvin, Janine; Pannala, Sreekanth

    2012-01-01

    With rapid advancements in computer hardware and numerical algorithms, computational fluid dynamics (CFD) has been increasingly employed as a useful tool for investigating the complex hydrodynamics inherent in multiphase flows. An important step during the development of a CFD model and prior to its application is conducting careful and comprehensive verification and validation studies. Accordingly, efforts to verify and validate the open-source MFIX-DEM software, which can be used for simulating the gas solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles, have been made at the National Energy Technology Laboratory (NETL). In part I of this paper, extensive verification studies were presented and in this part, detailed validation studies of MFIX-DEM are presented. A series of test cases covering a range of gas solids flow applications were conducted. In particular the numerical results for the random packing of a binary particle mixture, the repose angle of a sandpile formed during a side charge process, velocity, granular temperature, and voidage profiles from a bounded granular shear flow, lateral voidage and velocity profiles from a monodisperse bubbling fluidized bed, lateral velocity profiles from a spouted bed, and the dynamics of segregation of a binary mixture in a bubbling bed were compared with available experimental data, and in some instances with empirical correlations. In addition, sensitivity studies were conducted for various parameters to quantify the error in the numerical simulation.

  7. Open-Source MFIX-DEM Software for Gas-Solids Flows: Part II - Validation Studies

    SciTech Connect

    Li, Tingwen

    2012-04-01

    With rapid advancements in computer hardware and numerical algorithms, computational fluid dynamics (CFD) has been increasingly employed as a useful tool for investigating the complex hydrodynamics inherent in multiphase flows. An important step during the development of a CFD model and prior to its application is conducting careful and comprehensive verification and validation studies. Accordingly, efforts to verify and validate the open-source MFIX-DEM software, which can be used for simulating the gas–solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles, have been made at the National Energy Technology Laboratory (NETL). In part I of this paper, extensive verification studies were presented and in this part, detailed validation studies of MFIX-DEM are presented. A series of test cases covering a range of gas–solids flow applications were conducted. In particular the numerical results for the random packing of a binary particle mixture, the repose angle of a sandpile formed during a side charge process, velocity, granular temperature, and voidage profiles from a bounded granular shear flow, lateral voidage and velocity profiles from a monodisperse bubbling fluidized bed, lateral velocity profiles from a spouted bed, and the dynamics of segregation of a binary mixture in a bubbling bed were compared with available experimental data, and in some instances with empirical correlations. In addition, sensitivity studies were conducted for various parameters to quantify the error in the numerical simulation.

  8. DEM-based Modeling at the Hillslope Scale: Recent Results and Future Process Research Needs

    NASA Astrophysics Data System (ADS)

    McDonnell, J.; Coles, A.; Gabrielli, C. P.; Appels, W. M.; Ameli, A.

    2015-12-01

    Hillslope scale patterns of overland flow, infiltration, subsurface stormflow and groundwater recharge are all topographically mediated. However, the mechanisms by which macro-, meso- and micro-topographies control filling and spilling of lateral flow, and vertical infiltration, are still poorly understood. Here we present high-resolution DEMs derived from ground-based LiDAR, airborne LiDAR, and GPR (ground penetrating rebar!) with model analysis to examine the topographic controls on water flow at three distinct hillslopes. We explore surface topographic effects on rainfall- and snowmelt-infiltration and overland flow on the Canadian Prairies; the surface and subsurface topographic controls on lateral subsurface stormflow generation and groundwater recharge at a steep, wet temperate rainforest in New Zealand; and subsurface topographic controls on patterns of groundwater recharge at a forested hillslope on the Georgia Piedmont in the United States. We demonstrate how these studies reveal future research needs for improving DEM-based watershed delineation and modeling along with some surprising similarities between topographic controls on soil surface infiltration and overland flow and twin subsurface processes at the soil-bedrock interface.

  9. Region-growing segmentation to automatically delimit synthetic drumlins in 'real' DEMs

    NASA Astrophysics Data System (ADS)

    Eisank, Clemens; Smith, Mike; Hillier, John

    2013-04-01

    Mapping or 'delimiting' landforms is one of geomorphology's primary tools. Computer-based techniques, such as terrain segmentation, may potentially provide terrain units that are close to the size and shape of landforms. Whether terrain units represent landforms heavily depends on the segmentation algorithm, its settings and the type of underlying land-surface parameters (LSPs). We assess a widely used region-growing technique, i.e. the multiresolution segmentation (MRS) algorithm as implemented in object-based image analysis software, for delimiting drumlins. Supervised testing was based on five synthetic DEMs that included the same set of perfectly known drumlins at different locations. This, for the first time, removes subjectivity from the reference data. Five LSPs were tested, and four variants were computed for each using two pre- and post-processing options. The automated method (1) employs MRS to partition the input LSP into 200 ever coarser terrain unit patterns, (2) identifies the spatially best matching terrain unit for each reference drumlin, and (3) computes four accuracy metrics for quantifying the aerial match between delimited and reference drumlins. MRS performed best on LSPs that are regional, derived from a decluttered DEM and then normalized. Median scale parameters (SPs) for segments best delineating drumlins were relatively stable for the same LSP, but varied significantly between LSPs. Larger drumlins were generally delimited at higher SPs. MRS indicated high robustness against variations in the location and distribution of drumlins.

  10. Automatic Detection and Boundary Extraction of Lunar Craters Based on LOLA DEM Data

    NASA Astrophysics Data System (ADS)

    Li, Bo; Ling, ZongCheng; Zhang, Jiang; Wu, ZhongChen

    2015-07-01

    Impact-induced circular structures, known as craters, are the most obvious geographic and geomorphic features on the Moon. The studies of lunar carters' patterns and spatial distributions play an important role in understanding geologic processes of the Moon. In this paper, we proposed a method based on digital elevation model (DEM) data from lunar orbiter laser altimeter to detect the lunar craters automatically. Firstly, the DEM data of study areas are converted to a series of spatial fields having different scales, in which all overlapping depressions are detected in order (larger depressions first, then the smaller ones). Then, every depression's true boundary is calculated by Fourier expansion and shape parameters are computed. Finally, we recognize the craters from training sets manually and build a binary decision tree to automatically classify the identified depressions into craters and non-craters. In addition, our crater-detection method can provides a fast and reliable evaluation of ages of lunar geologic units, which is of great significance in lunar stratigraphy studies as well as global geologic mapping.

  11. Improvement of dem Generation from Aster Images Using Satellite Jitter Estimation and Open Source Implementation

    NASA Astrophysics Data System (ADS)

    Girod, L.; Nuth, C.; Kääb, A.

    2015-12-01

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system embarked on the Terra (EOS AM-1) satellite has been a source of stereoscopic images covering the whole globe at a 15m resolution at a consistent quality for over 15 years. The potential of this data in terms of geomorphological analysis and change detection in three dimensions is unrivaled and needs to be exploited. However, the quality of the DEMs and ortho-images currently delivered by NASA (ASTER DMO products) is often of insufficient quality for a number of applications such as mountain glacier mass balance. For this study, the use of Ground Control Points (GCPs) or of other ground truth was rejected due to the global "big data" type of processing that we hope to perform on the ASTER archive. We have therefore developed a tool to compute Rational Polynomial Coefficient (RPC) models from the ASTER metadata and a method improving the quality of the matching by identifying and correcting jitter induced cross-track parallax errors. Our method outputs more accurate DEMs with less unmatched areas and reduced overall noise. The algorithms were implemented in the open source photogrammetric library and software suite MicMac.

  12. Tectonic development of the Northwest Bonaparte Basin, Australia by using Digital Elevation Model (DEM)

    NASA Astrophysics Data System (ADS)

    Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Ragab Gaafar, Gamal; Yusoff, AP Wan Ismail Wan

    2016-02-01

    The Bonaparte Basin consist of majorly offshore part is situated at Australia's NW continental margin, covers an area of approx. 270,000km2. Bonaparte Basin having a number of sub-basins and platform areas of Paleozoic and Mesozoic is structurally complex. This research established the geologic and geomorphologic studies using Digital Elevation Model (DEM) as a substitute approach in morphostructural analysis to unravel the geological complexities. Although DEMs have been in practice since 1990s, they still have not become common tool for mapping studies. The research work comprised of regional structural analysis with the help of integrated elevation data, satellite imageries, available open topograhic images and internal geological maps with interpreted seismic. The structural maps of the study area have been geo-referenced which further overlaid onto SRTM data and satellite images for combined interpretation which facilitate to attain Digital Elevation Model of the study area. The methodology adopts is to evaluate and redefine development of geodynamic processes involved in formation of Bonaparte Basin. The main objectives is to establish the geological histories by using digital elevation model. The research work will be useful to incorporate different tectonic events occurred at different Geological times in a digital elevation model. The integrated tectonic analysis of different digital data sets benefitted substantially from combining them into a common digital database. Whereas, the visualization software facilitates the overlay and combined interpretation of different data sets which is helpful to reveal hidden information not obvious or accessible otherwise for regional analysis.

  13. Hydrological modeling using high resolution dem to level control on highways

    NASA Astrophysics Data System (ADS)

    Akbulut, Zeynep; Cömert, Çetin

    2016-04-01

    Floods are natural disasters that must be managed, controlled and taken precautions before it happens considering the damage they inflicted to environment and human lives. As to highways, the main vein of urban life flow, must be taken into consideration as a different entity that affected by excessive rainfalls and floods. Due to inadequate drainage that allow rainfall to form water ponds on highways cause vehicles to lose control and that lead vehicles to have traffic accidents. To reduce the traffic accidents caused by ponding waters on highways we need to know area of inundation and water depths. In this context we used FLO-2D Basic Model (2009) to hydrological modeling of Black Sea Coastal Highway with meteorological and hydrological data using a Digital Elevation Model (DEM). In this study, ponding areas on highways determined by simulating the rainfall with a high resolution DEM that can represent the actual road surface correctly. With this information, General Directorate of Highways (GDH) in Turkey can adjust the cross-sectional and longitudinal slope or build better and bigger drainage structures where water accumulated to prevent ponding. With the results obtained from Hydrological Model, GDH can rapidly control highways conformity to regulations before highways come into service. Also these ponding areas acquired by reveals where to prioritize in flood risk managements. Key Words: Area of Inundation, Digital Elevation Model, FLO-2D, Hydrological Modeling, Highway, Rainfall-Runoff Simulation, Water Depth.

  14. Soil properties and environmental tracers: A DEM based assessment in an Australian Mediterranean environment

    NASA Astrophysics Data System (ADS)

    Hancock, G. R.; Murphy, D. V.; Li, Y.

    2013-02-01

    Terrain properties vary at the hillslope and catchment scale and play a significant role in the distribution of water and sediment. Of particular interest in recent years has been the role of hillslope and catchment properties in the spatial and temporal distribution of soil organic carbon (SOC) and the ability to predict SOC from DEM terrain analysis. SOC plays a significant role in soil health and productivity as well as providing a significant store of terrestrial carbon. This study examined SOC concentration along representative pasture transects in a catchment located in southern Western Australia with a Mediterranean climate. Results demonstrate that the majority of SOC (%) is located in the near-surface (300 mm) and is concentrated in the top 0.2 m. There was no relationship found between SOC (or microbial biomass) and topography or topographic derivatives such as wetness and terrain indices from DEMs. Significant relationships were however found between SOC and environmental tracers (137Cs and 210Pbex) down the soil profile. Weak, yet significant, relationships were found between SOC and the environmental tracers along the hillslope transects, suggesting that organic carbon moves along the same pathways as clay particles in soil. An erosion assessment using 137Cs and also a numerical soil erosion and landscape evolution model found low and comparable erosion rates at the site. The results demonstrate that SOC concentration is relatively uniform across the study site and that a transect scale assessment can provide a measure of hillslope and catchment scale SOC in this environment.

  15. DEM generation from digital photographs using computer vision: Accuracy and application

    NASA Astrophysics Data System (ADS)

    James, M. R.; Robson, S.

    2012-12-01

    Data for detailed digital elevation models (DEMs) are usually collected by expensive laser-based techniques, or by photogrammetric methods that require expertise and specialist software. However, recent advances in computer vision research now permit 3D models to be automatically derived from unordered collections of photographs, and offer the potential for significantly cheaper and quicker DEM production. Here, we review the advantages and limitations of this approach and, using imagery of the summit craters of Piton de la Fournaise, compare the precisions obtained with those from formal close range photogrammetry. The surface reconstruction process is based on a combination of structure-from-motion and multi-view stereo algorithms (SfM-MVS). Using multiple photographs of a scene taken from different positions with a consumer-grade camera, dense point clouds (millions of points) can be derived. Processing is carried out by automated 'reconstruction pipeline' software downloadable from the internet. Unlike traditional photogrammetric approaches, the initial reconstruction process does not require the identification of any control points or initial camera calibration and is carried out with little or no operator intervention. However, such reconstructions are initially un-scaled and un-oriented so additional software has been developed to permit georeferencing. Although this step requires the presence of some control points or features within the scene, it does not have the relatively strict image acquisition and control requirements of traditional photogrammetry. For accuracy, and to allow error analysis, georeferencing observations are made within the image set, rather than requiring feature matching within the point cloud. Application of SfM-MVS is demonstrated using images taken from a microlight aircraft over the summit of Piton de la Fournaise volcano (courtesy of B. van Wyk de Vries). 133 images, collected with a Canon EOS D60 and 20 mm fixed focus lens, were

  16. BOREAS HYD-8 DEM Data Over the NSA-MSA and SSA-MSA in the UTM Projection

    NASA Technical Reports Server (NTRS)

    Wang, Xue-Wen; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Band, L. E.; Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS HYD-8 team focused on describing the scaling behavior of water and carbon flux processes at local and regional scales. These DEMs were produced from digitized contours at a cell resolution of 100 meters. Vector contours of the area were used as input to a software package that interpolates between contours to create a DEM representing the terrain surface. The vector contours had a contour interval of 25 feet. The data cover the BOREAS MSAs of the SSA and NSA and are given in a UTM map projection. Most of the elevation data from which the DEM was produced were collected in the 1970s or 1980s. The data are stored in binary, image format files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  17. The EVE plus RHESSI DEM for Solar Flares, and Implications for Residual Non-Thermal X-Ray Emission

    NASA Astrophysics Data System (ADS)

    McTiernan, James; Caspi, Amir; Warren, Harry

    2016-05-01

    Solar flare spectra are typically dominated by thermal emission in the soft X-ray energy range. The low energy extent of non-thermal emission can only be loosely quantified using currently available X-ray data. To address this issue, we combine observations from the EUV Variability Experiment (EVE) on-board the Solar Dynamics Observatory (SDO) with X-ray data from the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI) to calculate the Differential Emission Measure (DEM) for solar flares. This improvement over the isothermal approximation helps to resolve the ambiguity in the range where the thermal and non-thermal components may have similar photon fluxes. This "crossover" range can extend up to 30 keV.Previous work (Caspi et.al. 2014ApJ...788L..31C) concentrated on obtaining DEM models that fit both instruments' observations well. For this current project we are interested in breaks and cutoffs in the "residual" non-thermal spectrum; i.e., the RHESSI spectrum that is left over after the DEM has accounted for the bulk of the soft X-ray emission. As in our earlier work, thermal emission is modeled using a DEM that is parametrized as multiple gaussians in temperature. Non-thermal emission is modeled as a photon spectrum obtained using a thin-target emission model ('thin2' from the SolarSoft Xray IDL package). Spectra for both instruments are fit simultaneously in a self-consistent manner.For this study, we have examined the DEM and non-thermal resuidual emission for a sample of relatively large (GOES M class and above) solar flares observed from 2011 to 2014. The results for the DEM and non-thermal parameters found using the combined EVE-RHESSI data are compared with those found using only RHESSI data.

  18. The Use of DEM to Capture the Dynamics of the Flow of Solid Pellets in a Single Screw Extruder

    NASA Astrophysics Data System (ADS)

    Hong, He; Covas, J. A.; Gaspar-Cunha, A.

    2007-05-01

    Despite of the numerical developments on the numerical modeling of polymer plasticating single screw extrusion, the initial stages of solids conveying are still treated unsatisfactorily, a simple plug flow condition being assumed. It is well known that this produces poor predictions of relevant process parameters, e.g., output. This work reports on attempt to model the process using the Discrete Element Method (DEM) with the aim of unveiling the dynamics of the process. Using DEM each pellet is taken as a separate unit, thus predictions of flow patterns, velocity fields and degree of filling are possible. We present the algorithm and a few preliminary results.

  19. Zum Wissenschaftsverständnis der modernen Evolutionsbiologie

    NASA Astrophysics Data System (ADS)

    Sommer, Ralf J.

    Die moderne Evolutionsbiologie hat ihren Ursprung in den Arbeiten von Charles Darwin und Alfred Wallace (Darwin 1963). Der gemeinsame Ausgangspunkt des Evolutionsgedanken ist dabei die Beobachtung, dass die biologische Welt nicht konstant ist. Biologische Systeme und alle darin lebenden Organismen unterliegen über längere Zeiträume hinweg einer stetigen Veränderung. Diese grundlegende Eigenschaft biologischer Systeme macht die Biologie zu einer historischen Wissenschaft und stellt einen wichtigen Gegensatz zu großen Teilen der Physik dar. Obwohl die Aussage von der Veränderlichkeit der Arten heute trivial klingt, war sie im 19. Jahrhundert eine Revolution, da die Konstanz der Arten und der Welt eine vorherrschende Stellung im damaligen Weltbild hatte (Amundson 2005).

  20. High-resolution Pleiades DEMs and improved mapping methods for the E-Corinth marine terraces

    NASA Astrophysics Data System (ADS)

    de Gelder, Giovanni; Fernández-Blanco, David; Delorme, Arthur; Jara-Muñoz, Julius; Melnick, Daniel; Lacassin, Robin; Armijo, Rolando

    2016-04-01

    The newest generation of satellite imagery provides exciting new possibilities for highly detailed mapping, with ground resolution of sub-metric pixels and absolute accuracy within a few meters. This opens new venues for the analysis of geologic and geomorphic landscape features, especially since photogrammetric methods allow the extraction of detailed topographic information from these satellite images. We used tri-stereo imagery from the Pleiades platform of the CNES in combination with Euclidium software for image orientation, and Micmac software for dense matching, to develop state-of-the-art, 2m-resolution digital elevation models (DEMs) for eight areas in Greece. Here, we present our mapping results for an area in the eastern Gulf of Corinth, which contains one of the most extensive and well-preserved flights of marine terraces world-wide. The spatial extent of the terraces has been determined by an iterative combination of an automated surface classification model for terrain slope and roughness, and qualitative assessment of satellite imagery, DEM hillshade maps, slope maps, as well as detailed topographic analyses of profiles and contours. We determined marine terrace shoreline angles by means of swath profiles that run perpendicularly to the paleo-seacliffs, using the graphical interface TerraceM. Our analysis provided us with a minimum and maximum estimate of the paleoshoreline location on ~750 swath profiles, by using the present-day cliff slope as an approximation for its paleo-cliff counterpart. After correlating the marine terraces laterally we obtained 16 different terrace-levels, recording Quaternary sea-level highstands of both major interglacial and several interstadial periods. Our high-resolution Pleiades-DEMs and improved method for paleoshoreline determination allowed us to produce a marine terrace map of unprecedented detail, containing more terrace sub-levels than hitherto. Our mapping demonstrates that we are no longer limited by the

  1. Structural and Volumetric re-evaluation of the Vaiont landslide using DEM techniques

    NASA Astrophysics Data System (ADS)

    Superchi, Laura; Pedrazzini, Andrea; Floris, Mario; Genevois, Rinaldo; Ghirotti, Monica; Jaboyedoff, Michel

    2010-05-01

    On the 9th October 1963 a catastrophic landslide occurred on the southern slope of the Vaiont dam reservoir. A mass of approximately 270 million m3 collapsed into the reservoir generating a wave which overtopped the dam and hit the town of Longarone and other villages: almost 2000 people lost their lives. The large volume and high velocity of the landslide combined with the great destruction and loss of life that occurred make the Vaiont landslide as a natural laboratory to investigate landslide failure mechanisms and propagation. Geological, structural, geomorphological, hydrogeological and geomechanical elements should be, then, re-analyzed using methods and techniques not available in the '60s. In order to better quantify the volume involved in the movement and to assess the mechanism of the failure, a structural study is a preliminary and necessary step. The structural features have been investigated based on a digital elevation model (DEM) of the pre- and post-landslide topography at a pixel size of 5m and associated software (COLTOP-3D) to create a colored shaded relief map revealing the orientation of morphological features. Besides,the results allowed to identify on both pre- and post-slide surface six main discontinuity sets, some of which influence directly the Vaiont landslide morphology. Recent and old field surveys allowed to validate the COLTOP-3D analysis results. To estimate the location and shape of the sliding surface and to evaluate the volume of the landslide, the SLBL (Sloping Local Base Level) method has been used, a simple and efficient tool that allows a geometric interpretation of the failure surface based on a DEM. The SLBL application required a geological interpretation to define the contours of the landslide and to estimate the possible curvature of the sliding surface, that is defined by interpolating between points considered as limits of the landslide. The SLBL surface of the Vaiont landslide, was obtained from the DEM reconstruction

  2. MARE2DEM: a 2-D inversion code for controlled-source electromagnetic and magnetotelluric data

    NASA Astrophysics Data System (ADS)

    Key, Kerry

    2016-08-01

    This work presents MARE2DEM, a freely available code for 2-D anisotropic inversion of magnetotelluric (MT) data and frequency-domain controlled-source electromagnetic (CSEM) data from onshore and offshore surveys. MARE2DEM parameterizes the inverse model using a grid of arbitrarily shaped polygons, where unstructured triangular or quadrilateral grids are typically used due to their ease of construction. Unstructured grids provide significantly more geometric flexibility and parameter efficiency than the structured rectangular grids commonly used by most other inversion codes. Transmitter and receiver components located on topographic slopes can be tilted parallel to the boundary so that the simulated electromagnetic fields accurately reproduce the real survey geometry. The forward solution is implemented with a goal-oriented adaptive finite element method that automatically generates and refines unstructured triangular element grids that conform to the inversion parameter grid, ensuring accurate responses as the model conductivity changes. This dual-grid approach is significantly more efficient than the conventional use of a single grid for both the forward and inverse meshes since the more detailed finite element meshes required for accurate responses do not increase the memory requirements of the inverse problem. Forward solutions are computed in parallel with a highly efficient scaling by partitioning the data into smaller independent modeling tasks consisting of subsets of the input frequencies, transmitters and receivers. Non-linear inversion is carried out with a new Occam inversion approach that requires fewer forward calls. Dense matrix operations are optimized for memory and parallel scalability using the ScaLAPACK parallel library. Free parameters can be bounded using a new non-linear transformation that leaves the transformed parameters nearly the same as the original parameters within the bounds, thereby reducing non-linear smoothing effects. Data

  3. MARE2DEM: a 2-D inversion code for controlled-source electromagnetic and magnetotelluric data

    NASA Astrophysics Data System (ADS)

    Key, Kerry

    2016-10-01

    This work presents MARE2DEM, a freely available code for 2-D anisotropic inversion of magnetotelluric (MT) data and frequency-domain controlled-source electromagnetic (CSEM) data from onshore and offshore surveys. MARE2DEM parametrizes the inverse model using a grid of arbitrarily shaped polygons, where unstructured triangular or quadrilateral grids are typically used due to their ease of construction. Unstructured grids provide significantly more geometric flexibility and parameter efficiency than the structured rectangular grids commonly used by most other inversion codes. Transmitter and receiver components located on topographic slopes can be tilted parallel to the boundary so that the simulated electromagnetic fields accurately reproduce the real survey geometry. The forward solution is implemented with a goal-oriented adaptive finite-element method that automatically generates and refines unstructured triangular element grids that conform to the inversion parameter grid, ensuring accurate responses as the model conductivity changes. This dual-grid approach is significantly more efficient than the conventional use of a single grid for both the forward and inverse meshes since the more detailed finite-element meshes required for accurate responses do not increase the memory requirements of the inverse problem. Forward solutions are computed in parallel with a highly efficient scaling by partitioning the data into smaller independent modeling tasks consisting of subsets of the input frequencies, transmitters and receivers. Non-linear inversion is carried out with a new Occam inversion approach that requires fewer forward calls. Dense matrix operations are optimized for memory and parallel scalability using the ScaLAPACK parallel library. Free parameters can be bounded using a new non-linear transformation that leaves the transformed parameters nearly the same as the original parameters within the bounds, thereby reducing non-linear smoothing effects. Data

  4. Implementation of large-scale landscape evolution modelling to real high-resolution DEM

    NASA Astrophysics Data System (ADS)

    Schroeder, S.; Babeyko, A. Y.

    2012-12-01

    We have developed a surface evolution model to be naturally integrated with 3D thermomechanical codes like SLIM-3D to study coupled tectonic-climate interaction. The resolution of the surface evolution model is independent of that of the underlying continuum box. The surface model follows the concept of the cellular automaton implemented on a regular Eulerian mesh. It incorporates an effective filling algorithm that guarantees flow direction in each cell, D8 search for flow directions, computation of discharges and bedrock incision. Additionally, the model implements hillslope erosion in the form of non-linear, slope-dependent diffusion. The model was designed to be employed not only to synthetic topographies but also to real Digital Elevation Models (DEM). In present work we report our experience with model implication to the 30-meter resolution ASTER GDEM of the Pamir orogen, in particular, to the segment of the Panj river. We start with calibration of the model parameters (fluvial incision and hillslope diffusion coefficients) using direct measurements of Panj incision rates and volumes of suspended sediment transport. Since the incision algorithm is independent on hillslope processes, we first adjust the incision parameters. Power-law exponents of the incision equation were evaluated from the profile curvature of the main Pamir rivers. After that, incision coefficient was adjusted to fit the observed incision rate of 5 mm/y. Once the model results are consistent with the measured data, the calibration of hillslope processes follows. For given critical slope, diffusivity could be fitted to match the observed sediment discharge. Applying of surface evolution model to real DEM reveals specific problems which do not appear when working with synthetic landscapes. One of them is the noise of the satellite-measured topography. In particular, due to the non-vertical observation perspective, satellite may not be able to detect the bottom of the river channel, especially

  5. Semi-automated extraction of landslides in Taiwan based on SPOT imagery and DEMs

    NASA Astrophysics Data System (ADS)

    Eisank, Clemens; Hölbling, Daniel; Friedl, Barbara; Chen, Yi-Chin; Chang, Kang-Tsung

    2014-05-01

    The vast availability and improved quality of optical satellite data and digital elevation models (DEMs), as well as the need for complete and up-to-date landslide inventories at various spatial scales have fostered the development of semi-automated landslide recognition systems. Among the tested approaches for designing such systems, object-based image analysis (OBIA) stepped out to be a highly promising methodology. OBIA offers a flexible, spatially enabled framework for effective landslide mapping. Most object-based landslide mapping systems, however, have been tailored to specific, mainly small-scale study areas or even to single landslides only. Even though reported mapping accuracies tend to be higher than for pixel-based approaches, accuracy values are still relatively low and depend on the particular study. There is still room to improve the applicability and objectivity of object-based landslide mapping systems. The presented study aims at developing a knowledge-based landslide mapping system implemented in an OBIA environment, i.e. Trimble eCognition. In comparison to previous knowledge-based approaches, the classification of segmentation-derived multi-scale image objects relies on digital landslide signatures. These signatures hold the common operational knowledge on digital landslide mapping, as reported by 25 Taiwanese landslide experts during personal semi-structured interviews. Specifically, the signatures include information on commonly used data layers, spectral and spatial features, and feature thresholds. The signatures guide the selection and implementation of mapping rules that were finally encoded in Cognition Network Language (CNL). Multi-scale image segmentation is optimized by using the improved Estimation of Scale Parameter (ESP) tool. The approach described above is developed and tested for mapping landslides in a sub-region of the Baichi catchment in Northern Taiwan based on SPOT imagery and a high-resolution DEM. An object

  6. Sediment micromechanics in sheet flows induced by asymmetric waves: A CFD-DEM study

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Xiao, Heng

    2016-11-01

    Understanding the sediment transport in oscillatory flows is essential to the investigation of the overall sediment budget for coastal regions. This overall budget is crucial for the prediction of the morphological change of the coastline in engineering applications. Since the sediment transport in oscillatory flows is dense particle-laden flow, appropriate modeling the particle interaction is critical. Although traditional two-fluid approaches have been applied to the study of sediment transport in oscillatory flows, the approaches do not capture the interaction of the particles. The study of the motion of individual sediment particles and their micromechanics (e.g., packing and contact force) in oscillatory flows is still lacking. In this work, a parallel CFD-DEM solver SediFoam that can model the inter-particle collision is applied to study the granular micromechanics of sediment particles in oscillatory flows. The results obtained from the CFD-DEM solver are validated by using the experimental data of coarse and medium sands. The comparison with experimental results suggests that the flow velocity, the sediment flux and the net sediment transport rate predicted by SediFoam are satisfactory. Moreover, the micromechanic quantities of the sediment bed are presented in detail, including the Voronoi concentration, the coordination number, and the particle interaction force. It is demonstrated that the variation of these micromechanic quantities at different phases in the oscillatory cycle is significant, which is due to different responses of the sediment bed. To investigate the structural properties of the sediment bed, the correlation of the Voronoi volume fraction and coordination number is compared to the results from the fluidized bed simulations. The consistency in the comparison indicates the structural micromechanics of sediment transport and fluidized bed are similar despite the differences in flow patterns. From the prediction of the CFD-DEM model, we

  7. Bereits nach Ablauf der Halbwertszeit droht der vollständige Zerfall Die britische Atomic Scientists’ Association, die Ideologie der „objektiven” Wissenschaft und die H-Bombe

    NASA Astrophysics Data System (ADS)

    Laucht, Christoph

    Präsident Harry Trumans Verlautbarung vom 31.1.1950, seine Regierung wolle die Entwicklung der Wasserstoffbombe vorantreiben, fand große Beachtung in den britischen Medien. Die illustrierte Zeitschrift Picture Post widmete der HBombe einen Artikel, der unter anderem kurze Stellungnahmen der britischen Atomwissenschaftler Eric Burhop, Kathleen Lonsdale, Harrie Massey, Rudolf Peierls und Maurice Pryce enthielt, die alle Mitglieder der Atomic Scientists' Association (ASA) waren.

  8. Phänomenologische Grundlagen der Wärmelehre

    NASA Astrophysics Data System (ADS)

    Heintze, Joachim

    Die Physik der Wärme lässt sich auf zweierlei Weise formulieren: Einmal als Mechanik eines Systems, das eine enorm große Zahl von Teilchen enthält (statistische Mechanik), und einmal mit Hilfe von ad hoc eingeführten Größen, den sogenannten Zustandsgrößen, die geeignet sind, das Verhalten eines solchen Systems zu beschreiben, ohne dass man die Teilchen selbst und ihre Bewegungen betrachten muss (Thermodynamik). Wir werden beide Ansätze in ihrer einfachsten und anschaulichsten Ausprägung in Kap. 5 (kinetische Gastheorie) bzw. in Kap. 8 (Grundbegriffe der Thermodynamik) behandeln. Obgleich sich die volle Durchführung des Programms als begrifflich und mathematisch recht schwierig erweist - die Vorlesung "Thermodynamik und Statistik" steht gewöhnlich am Ende der Kursvorlesungen über theoretische Physik - werden wir doch auf der Grundlage der Kap. 5 und 8 eine Menge über die Physik der Wärme lernen können. Den Ausgangspunkt der Wärmelehre bilden jedoch allemal die Naturerscheinungen, die wir hier in Kap. 4 behandeln wollen: Wärme, Kälte, Temperaturausgleich. Wir werden untersuchen, wie man diese Begriffe quantifizieren kann, und was bei der Erwärmung oder Abkühlung eines Körpers vor sich geht. Dabei werden wir auf den I. und II. Hauptsatz der Wärmelehre stoßen.

  9. Information Interaction Study for DER and DMS Interoperability

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Lu, Yiming; Lv, Guangxian; Liu, Peng; Chen, Yu; Zhang, Xinhui

    The Common Information Model (CIM) is an abstract data model that can be used to represent the major objects in Distribution Management System (DMS) applications. Because the Common Information Model (CIM) doesn't modeling the Distributed Energy Resources (DERs), it can't meet the requirements of DER operation and management for Distribution Management System (DMS) advanced applications. Modeling of DER were studied based on a system point of view, the article initially proposed a CIM extended information model. By analysis the basic structure of the message interaction between DMS and DER, a bidirectional messaging mapping method based on data exchange was proposed.

  10. 3DEM Loupe: Analysis of macromolecular dynamics using structures from electron microscopy.

    PubMed

    Nogales-Cadenas, R; Jonic, S; Tama, F; Arteni, A A; Tabas-Madrid, D; Vázquez, M; Pascual-Montano, A; Sorzano, C O S

    2013-07-01

    Electron microscopy (EM) provides access to structural information of macromolecular complexes in the 3-20 Å resolution range. Normal mode analysis has been extensively used with atomic resolution structures and successfully applied to EM structures. The major application of normal modes is the identification of possible conformational changes in proteins. The analysis can throw light on the mechanism following ligand binding, protein-protein interactions, channel opening and other functional macromolecular movements. In this article, we present a new web server, 3DEM Loupe, which allows normal mode analysis of any uploaded EM volume using a user-friendly interface and an intuitive workflow. Results can be fully explored in 3D through animations and movies generated by the server. The application is freely available at http://3demloupe.cnb.csic.es.

  11. Issues with using high-resolution DEMs for fluvial geomorphology modelling

    NASA Astrophysics Data System (ADS)

    Castro, Andres

    2015-04-01

    It is widely recognized that undertaking detailed fluvial morphology studies can be a difficult and expensive task due to the high amount of resources, such as time and highly trained personnel, that such studies requires in order to obtain accurate results. Yet, for a wide range of projects that in one way or another require the understanding fluvial systems, engineers are frequently challenged with the daunting task of managing expenses within tight budgets and expecting high quality results. It is with this perspective that it is often desired to simplify processes while maintaining a high reliability of results. In an attempt to tackle this issue the current PhD research presents an alternative methodology to undertake river geomorphology studies, by applying an automated procedure to model stream power from DEMs generated from high resolution LiDAR data. The main aim of the research is to estimate the stream power distribution along selected UK catchments and link the estimated stream power values to floodplain development processes. The raw LiDAR data, in the form of ASCII text files, used for the study correspond to 1m, 2m and 10m resolutions. During the process of creating the DEM of one of the selected rivers, the River Teme, the presence of a number of "blank spots" within the mosaic was noted. These areas corresponded to NoData zones generated presumably from the deflection of the laser beam on a water surface. Given that the GIS software didn't consider the missing data areas as part of the DEM, even though most of the "blank spots" were located on the river channel, it was necessary to develop a procedure in order to eliminate the NoData zones and correct the DEM, prior to undertaking the hydrological analysis of the catchment, without compromising the quality of the rest of the data. In search of an improved quality of results it has been commonly assumed that the higher resolution of the data the better and more accurate results are to be obtained

  12. Mechanical behavior modeling of sand-rubber chips mixtures using discrete element method (DEM)

    NASA Astrophysics Data System (ADS)

    Eidgahee, Danial Rezazadeh; Hosseininia, Ehsan Seyedi

    2013-06-01

    Rubber shreds in mixture with sandy soils are widely used in geotechnical purposes due to their specific controlled compressibility characteristics and light weight. Various studies have been carried out for sand or rubber chips content in order to restrain the compressibility of the mass in different structures such as backfills, road embankments, etc. Considering different rubber contents, sand-rubber mixtures can be made which lead mechanical properties of the blend to go through changes. The aim of this paper is to study the effect of adding different rubber portions on the global engineering properties of the mixtures. This study is performed by using Discrete Element Method (DEM). The simulations showed that adding rubber up to a particular fraction can improve maximum bearing stress characteristics comparing to sand alone masses. Taking the difference between sand and rubber stiffness into account, the result interpretation can be developed to other soft and rigid particle mixtures such as powders or polymers.

  13. A coupled DEM-DFN approach to rock mass strength characterization

    NASA Astrophysics Data System (ADS)

    Harthong, Barthelemy; Scholtes, Luc; Donze, Frederic

    2013-04-01

    An enhanced version of the discrete element method (DEM) has been specifically developed for the analysis of fractured rock masses [Scholtes L, Donze F, 2012]. In addition to the discrete representation of the intact medium which enables the description of the localized stress-induced damage caused by heterogeneities inherent to rocks, structural defects can be explicitly taken into account in the modeling to represent pre-existing fractures or discontinuities of size typically larger than the discrete element size. From laboratory scale simulations to slope stability case studies, the capability of this approach to simulate the progressive failure mechanisms occurring in jointed rock are presented is assessed on the basis of referenced experiments and in situ observations. For instance, the challenging wing crack extension, typical of brittle material fracturing, can be successfully reproduced under both compressive and shear loading path, as a result of the progressive coalescence of micro-cracks induced by stress concentration at the tips of pre-existing fractures. In this study, the dedicated DEM is coupled to a discrete fracture network (DFN) model to assess the influence of DFN properties on the mechanical behavior of fractured rock masses where progressive failure can occur. The DFN model assumes the distribution of fractures barycentres to be fractal and the distribution of fracture sizes to follow a power-law distribution [Davy P, Le Goc P, Darcel C, Bour O, de Dreuzy JR, Munier R, 2010]. The proposed DEM/DFN model is used to characterize the influence of clustering and size distribution of pre-existing fractures on the strength of fractured rock masses. The results show that the mechanical behaviour of fractured rock masses is mainly dependent on the fracture intensity. However, for a given fracture intensity, the strength can exhibit a 50 per cent variability depending on the size distribution of the pre-existing fractures. This difference can be

  14. Mechanistic Based DEM Simulation of Particle Attrition in a Jet Cup

    SciTech Connect

    Xu, Wei; DeCroix, David; Sun, Xin

    2014-02-01

    The attrition of particles is a major industrial concern in many fluidization systems as it can have undesired effects on the product quality and on the reliable operation of process equipment. Therefore, to accomodate the screening and selection of catalysts for a specific process in fluidized beds, risers, or cyclone applications, their attrition propensity is usually estimated through jet cup attrition testing, where the test material is subjected to high gas velocities in a jet cup. However, this method is far from perfect despite its popularity, largely due to its inconsistency in different testing set-ups. In order to better understand the jet cup testing results as well as their sensitivity to different operating conditions, a coupled computational fluid dynamic (CFD) - discrete element method (DEM) model has been developed in the current study to investigate the particle attrition in a jet cup and its dependence on various factors, e.g. jet velocity, initial particle size, particle density, and apparatus geometry.

  15. Robust 3D Quantification of Glacial Landforms: A Use of Idealised Drumlins in a Real DEM

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Smith, M. S.

    2012-04-01

    Drumlins' attributes, such as height (h) and volume (V ), may preserve important information about the dynamics of former ice sheets. However, measurement errors are large (e.g., 39.2% of V within ±25% of their real values for the 'cookie cutter') and, in general, poorly understood. To accurately quantify the morphology of glacial landforms, the relief belonging to that landform must be reliably isolated from other components of the landscape (e.g. buildings, hills). A number of techniques have been proposed for this regional-residual separation (RRS). Which is best? Justifications for those applied remain qualitative assertions. A recently developed, novel method using idealised drumlins of known size (hin, V in) in a real digital elevation model (DEM) is used to quantitatively determine the best RRS technique, allowing general guidelines for quantifying glacial landforms to be proposed. 184 drumlins with digitised outlines in western Central Scotland are used as a case study. The NEXTMap surface model (DSM) is the primary dataset employed. A variety of techniques are then investigated for their ability to recover sizes (hr, V r). A metric, ɛ, is used that maximises the number of Hr/Hin values near 1.0 whilst giving equal weight to different drumlin sizes: a metric dominated by the large number of small drumlins is not desirable. For simplicity, the semi-automated 'cookie cutter' technique is used as a baseline for comparison. This removes heights within a drumlin from a DEM, cuts a hole, then estimates its basal surface by interpolating across the space with a fully tensioned bi-cubic spline (-T1). Metrics for h and V are ɛh = 0.885 and ɛV = 0.247. Other tensions do not improve this significantly, with ɛV of 0.245 at best, but using Delauney triangulation reduces ɛV to 0.206. Windowed 'sliding median' filters, which do not require heights within drumlins to be removed, attain a minimum ɛV of 0.470 at a best width of 340 m (-Fm340). Finally, even crudely

  16. Split-Band Interferometric SAR Processing Using TanDEM-X Data

    NASA Astrophysics Data System (ADS)

    De Rauw, Dominique; Kervyn, Francois; d'Oreye, Nicolas; Smets, Benoit; Albino, Fabien; Barbier, Christian

    2015-05-01

    Most recent SAR sensors use wide band signals to achieve metric range resolution. One can also take advantage of wide band to split it into sub-bands and generate several lower-resolution images, centered on slightly different frequencies, from a single acquisition. This process, named Multi Chromatic Analysis (MCA) corresponds to performing a spectral analysis of SAR images. Split-Band SAR interferometry (SBInSAR) is based on spectral analysis performed on each image of an InSAR pair, yielding a stack of sub-band interferograms. Scatterers keeping a coherent behaviour in each sub-band interferogram show a phase that varies linearly with the carrier frequency, the slope being proportional to the absolute optical path difference. This potentially solves the problems of phase unwrapping on a pixel-per-pixel basis. In this paper, we present an SBInSAR processor and its application using TanDEM-X data over the Nyiragongo volcano.

  17. Revealing topographic lineaments through IHS enhancement of DEM data. [Digital Elevation Model

    NASA Technical Reports Server (NTRS)

    Murdock, Gary

    1990-01-01

    Intensity-hue-saturation (IHS) processing of slope (dip), aspect (dip direction), and elevation to reveal subtle topographic lineaments which may not be obvious in the unprocessed data are used to enhance digital elevation model (DEM) data from northwestern Nevada. This IHS method of lineament identification was applied to a mosiac of 12 square degrees using a Cray Y-MP8/864. Square arrays from 3 x 3 to 31 x 31 points were tested as well as several different slope enhancements. When relatively few points are used to fit the plane, lineaments of various lengths are observed and a mechanism for lineament classification is described. An area encompassing the gold deposits of the Carlin trend and including the Rain in the southeast to Midas in the northwest is investigated in greater detail. The orientation and density of lineaments may be determined on the gently sloping pediment surface as well as in the more steeply sloping ranges.

  18. A Progressive Black Top Hat Transformation Algorithm for Estimating Valley Volumes from DEM Data

    NASA Astrophysics Data System (ADS)

    Luo, W.; Pingel, T.; Heo, J.; Howard, A. D.

    2013-12-01

    The amount of valley incision and valley volume are important parameters in geomorphology and hydrology research, because they are related to the amount erosion (and thus the volume of sediments) and the amount of water needed to create the valley. This is not only the case for terrestrial research but also for planetary research as such figuring out how much water was on Mars. With readily available digital elevation model (DEM) data, the Black Top Hat (BTH) transformation, an image processing technique for extracting dark features on a variable background, has been applied to DEM data to extract valley depth and estimate valley volume. However, previous studies typically use one single structuring element size for extracting the valley feature and one single threshold value for removing noise, resulting in some finer features such as tributaries not being extracted and underestimation of valley volume. Inspired by similar algorithms used in LiDAR data analysis to separate above ground features and bare earth topography, here we propose a progressive BTH (PBTH) transformation algorithm, where the structuring elements size is progressively increased to extract valleys of different orders. In addition, a slope based threshold was introduced to automatically adjust the threshold values for structuring elements with different sizes. Connectivity and shape parameters of the masked regions were used to keep the long linear valleys while removing other smaller non-connected regions. Preliminary application of the PBTH to Grand Canyon and two sites on Mars has produced promising results. More testing and fine-tuning is in progress. The ultimate goal of the project is to apply the algorithm to estimate the volume of valley networks on Mars and the volume of water needed to form the valleys we observe today and thus infer the nature of the hydrologic cycle on early Mars. The project is funded by NASA's Mars Data Analysis program.

  19. Interannual surface evolution of an Antarctic blue-ice moraine using multi-temporal DEMs

    NASA Astrophysics Data System (ADS)

    Westoby, Matthew J.; Dunning, Stuart A.; Woodward, John; Hein, Andrew S.; Marrero, Shasta M.; Winter, Kate; Sugden, David E.

    2016-06-01

    Multi-temporal and fine-resolution topographic data products are increasingly used to quantify surface elevation change in glacial environments. In this study, we employ 3-D digital elevation model (DEM) differencing to quantify the topographic evolution of a blue-ice moraine complex in front of Patriot Hills, Heritage Range, Antarctica. Terrestrial laser scanning (TLS) was used to acquire multiple topographic datasets of the moraine surface at the beginning and end of the austral summer season in 2012/2013 and during a resurvey field campaign in 2014. A complementary topographic dataset was acquired at the end of season 1 through the application of structure from motion with multi-view stereo (SfM-MVS) photogrammetry to a set of aerial photographs acquired from an unmanned aerial vehicle (UAV). Three-dimensional cloud-to-cloud differencing was undertaken using the Multiscale Model to Model Cloud Comparison (M3C2) algorithm. DEM differencing revealed net uplift and lateral movement of the moraine crests within season 1 (mean uplift ~ 0.10 m) and surface lowering of a similar magnitude in some inter-moraine depressions and close to the current ice margin, although we are unable to validate the latter. Our results indicate net uplift across the site between seasons 1 and 2 (mean 0.07 m). This research demonstrates that it is possible to detect dynamic surface topographical change across glacial moraines over short (annual to intra-annual) timescales through the acquisition and differencing of fine-resolution topographic datasets. Such data offer new opportunities to understand the process linkages between surface ablation, ice flow and debris supply within moraine ice.

  20. Open-source MFIX-DEM software for gas-solids flows: Part 1 - Verification studies

    SciTech Connect

    Garg, Rahul; Galvin, Janine; Li, Tingwen; Pannala, Sreekanth

    2012-04-01

    With rapid advancements in computer hardware, it is now possible to perform large simulations of granular flows using the Discrete Element Method (DEM). As a result, solids are increasingly treated in a discrete Lagrangian fashion in the gas–solids flow community. In this paper, the open-source MFIX-DEM software is described that can be used for simulating the gas–solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles. This method is referred to as the continuum discrete method (CDM) to clearly make a distinction between the ambiguity of using a Lagrangian or Eulerian reference for either continuum or discrete formulations. This freely available CDM code for gas–solids flows can accelerate the research in computational gas–solids flows and establish a baseline that can lead to better closures for the continuum modeling (or traditionally referred to as two fluid model) of gas–solids flows. In this paper, a series of verification cases is employed which tests the different aspects of the code in a systematic fashion by exploring specific physics in gas–solids flows before exercising the fully coupled solution on simple canonical problems. It is critical to have an extensively verified code as the physics is complex with highly-nonlinear coupling, and it is difficult to ascertain the accuracy of the results without rigorous verification. These series of verification tests set the stage not only for rigorous validation studies (performed in part II of this paper) but also serve as a procedure for testing any new developments that couple continuum and discrete formulations for gas–solids flows.

  1. Open Source MFIX-DEM Software for Gas-Solids Flows: Part 1 - Verification Studies

    SciTech Connect

    Garg, Rahul; Galvin, Janine; Li, Tingwen; Pannala, Sreekanth

    2012-04-01

    With rapid advancements in computer hardware, it is now possible to perform large simulations of granular flows using the Discrete Element Method (DEM). As a result, solids are increasingly treated in a discrete Lagrangian fashion in the gas–solids flow community. In this paper, the open-source MFIX-DEM software is described that can be used for simulating the gas–solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles. This method is referred to as the continuum discrete method (CDM) to clearly make a distinction between the ambiguity of using a Lagrangian or Eulerian reference for either continuum or discrete formulations. This freely available CDM code for gas–solids flows can accelerate the research in computational gas–solids flows and establish a baseline that can lead to better closures for the continuum modeling (or traditionally referred to as two fluid model) of gas–solids flows. In this paper, a series of verification cases is employed which tests the different aspects of the code in a systematic fashion by exploring specific physics in gas–solids flows before exercising the fully coupled solution on simple canonical problems. It is critical to have an extensively verified code as the physics is complex with highly-nonlinear coupling, and it is difficult to ascertain the accuracy of the results without rigorous verification. These series of verification tests set the stage not only for rigorous validation studies (performed in part II of this paper) but also serve as a procedure for testing any new developments that couple continuum and discrete formulations for gas–solids flows.

  2. Open-source MFIX-DEM software for gas-solids flows: Part I verification studies

    SciTech Connect

    Garg, Rahul; Galvin, Janine; Li, Tingwen; Pannala, Sreekanth

    2012-01-01

    With rapid advancements in computer hardware, it is now possible to perform large simulations of granular flows using the Discrete Element Method (DEM). As a result, solids are increasingly treated in a discrete Lagrangian fashion in the gas solids flow community. In this paper, the open-source MFIX-DEM software is described that can be used for simulating the gas solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles. This method is referred to as the continuum discrete method (CDM) to clearly make a distinction between the ambiguity of using a Lagrangian or Eulerian reference for either continuum or discrete formulations. This freely available CDM code for gas solids flows can accelerate the research in computational gas solids flows and establish a baseline that can lead to better closures for the continuum modeling (or traditionally referred to as two fluid model) of gas solids flows. In this paper, a series of verification cases is employed which tests the different aspects of the code in a systematic fashion by exploring specific physics in gas solids flows before exercising the fully coupled solution on simple canonical problems. It is critical to have an extensively verified code as the physics is complex with highly-nonlinear coupling, and it is difficult to ascertain the accuracy of the results without rigorous verification. These series of verification tests set the stage not only for rigorous validation studies (performed in part II of this paper) but also serve as a procedure for testing any new developments that couple continuum and discrete formulations for gas solids flows.

  3. Supernova Remnants in the Magellanic Clouds. VI. The DEM L316 Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Williams, R. M.; Chu, Y.-H.

    2005-12-01

    The DEM L316 system contains two shells, both with the characteristic signatures of supernova remnants (SNRs). We analyze Chandra and XMM-Newton data for DEM L316, investigating its spatial and spectral X-ray features. Our Chandra observations resolve the structure of the northeastern SNR (shell A) as a bright inner ring and a set of ``arcs'' surrounded by fainter diffuse emission. The spectrum is well fit by a thermal plasma model with a temperature of ~1.4 keV; we do not find significant spectral differences for different regions of this SNR. The southwestern SNR (shell B) exhibits an irregular X-ray outline, with a brighter interior ring of emission including a bright knot of emission. Overall, the emission of the SNR is well described by a thermal plasma of temperature ~0.6 keV. The bright knot, however, is spectrally distinct from the rest of the SNR, requiring the addition of a high-energy spectral component consistent with a power-law spectrum of photon index 1.6-1.8. We confirm the findings of Nishiuchi and coworkers that the spectra of these shells are notably different, with shell A requiring a high iron abundance for a good spectral fit, implying a Type Ia origin. We further explicitly compare abundance ratios to model predictions for Type Ia and Type II supernovae. The low ratios for shell A (O/Fe of 1.5 and Ne/Fe of 0.2) and the high ratios for shell B (O/Fe of 30-130 and Ne/Fe of 8-16) are consistent with Type Ia and Type II origins, respectively. The difference between the SNR progenitor types casts some doubt on the suggestion that these SNRs are interacting with one another.

  4. Quality of DEMs derived from Kite Aerial Photogrammety System: a case study of Dutch coastal environments.

    NASA Astrophysics Data System (ADS)

    Paron, Paolo; Smith, Mike J.; Anders, Niels; Meesuk, Vorawit

    2014-05-01

    Coastal protection is one of the main challenges for the Netherlands, where a large proportion of anthropogenic activity is located below sea level (both residential and economic). The Dutch government is implementing an innovative method of coastal replenishment using natural waves and winds to relocate sand from one side to the other of the country. This requires close monitoring of the spatio-temporal evolution of beaches in order to correctly model the future direction and amount of sand movement. To do so -on the onshore beach- we tested a Kite-Aerial Photography System for monitoring the beach dynamics at Zandmotor (http://www.dezandmotor.nl/en-GB/). The equipment used for data collection were a commercial DSLR camera (Nikon D7000 with a 20mm lens), gyro-levelled rig, Sutton Flowform 16 kite and Leica GNSS Viva GS10, with GSM connection to the Dutch geodetic network. We flew using a 115 m line with an average inclination of 40 to 45°; this gave a camera vertical distance of ~80 m and pixel size of ~20 mm. The methodology follows that of Smith et al. (2009), and of Paron & Smith (2013), applied to a highly dynamic environment with low texture and small relief conditions. Here we present a comparison of the quality of the digital elevation model (DEM) generated from the same dataset using two different systems: Structure from Motion (SfM) using Agisoft Photoscan Pro and traditional photogrammetry using Leica Photograpmmetry Suite. In addition the outputs from the two data processing methods are presented, including both an image mosaic and DEM, and highlighting pros and cons of both methods. References Smith, M. J. et al. 2009. High spatial resolution data acquisition for the geosciences: kite aerial photography. ESPL, 34(1), 155-161. Paron, P., Smith, M.J. 2013. Kite aerial photogrammetry system for monitoring coastal change in the Netherlands. 8th IAG International Conference on Geomorphology, Paris, August.

  5. Exploring the Potential of TanDEM-X Data in Rice Monitoring

    NASA Astrophysics Data System (ADS)

    Erten, E.

    2015-12-01

    In this work, phenological parameters such as growth stage, calendar estimation, crop density and yield estimation for rice fields are estimated employing TanDEM-X data. Currently, crop monitoring is country-dependent. Most countries have databases based on cadastral information and annual farmer inputs. Inaccuracies are coming from wrong or missing farmer declarations and/or coarsely updated cadastral boundary definitions. This leads to inefficient regulation of the market, frauds as well as to ecological risks. An accurate crop calendar is also missing, since farmers provide estimations in advance and there is no efficient way to know the growth status over large plantations. SAR data is of particular interest for these purposes. The proposed method includes two step approach including field detection and phenological state estimation. In the context of precise farming it is substantial to define field borders which are usually changing every cultivation period. Linking the SAR inherit properties to transplanting practice such as irrigation, the spatial database of rice-planted agricultural crops can be updated. Boundaries of agricultural fields will be defined in the database, and assignments of crops and sowing dates will be continuously updated by our monitoring system considering that sowing practice variously changes depending on the field owner decision. To define and segment rice crops, the system will make use of the fact that rice fields are characterized as flooded parcels separated by path networks composed by soil or rare grass. This natural segmentation is well detectable by inspecting low amplitude and coherence values of bistatic acquisitions. Once the field borders are defined, the phenology estimation of crops monitored at any time is the key point of monitoring. In this aspect the wavelength and the polarization option of TanDEM-X are enough to characterize the small phenological changes. The combination of bistatic interferometry and Radiative

  6. S1-Leitlinie zur UV-Phototherapie und Photochemotherapie.

    PubMed

    Herzinger, Thomas; Berneburg, Mark; Ghoreschi, Kamran; Gollnick, Harald; Hölzle, Erhard; Hönigsmann, Herbert; Lehmann, Percy; Peters, Thorsten; Röcken, Martin; Scharffetter-Kochanek, Karin; Schwarz, Thomas; Simon, Jan; Tanew, Adrian; Weichenthal, Michael

    2016-08-01

    Die heilsame Wirkung des Sonnenlichts war teilweise schon im Altertum bekannt und fand in der zweiten Hälfte des 19. Jahrhunderts wieder zunehmend Beachtung. Den Beginn der modernen Phototherapien markiert die Entwicklung einer Apparatur zur ultravioletten Bestrahlung der Hauttuberkulose durch Finnsen zu Beginn des zwanzigsten Jahrhunderts. Zur Therapie von Hauterkrankungen finden beinahe ausschließlich die spektralen Bereiche unterhalb des sichtbaren Lichtes (ultraviolett) Anwendung. Seit den 1970er Jahren stehen zunehmend leistungsfähige künstliche Strahlenquellen bereit für die Therapie mit UVB, UVA und die Kombination von UVA mit Photosensibilisatoren (Photochemotherapie). Hohe strukturelle und prozedurale Qualitätsstandards sind unabdingbare Voraussetzung für die Durchführung einer gleichermaßen wirkungsvollen wie auch sicheren Phototherapie. Die Leitlinie formuliert den aktuellen Konsens führender Experten auf dem Gebiet der Phototherapie in Bezug auf die Indikationen für die jeweiligen Therapieverfahren, deren Gegenanzeigen und Nebenwirkungen und insbesondere für die Wahl der korrekten Dosis zu Beginn und im Verlauf einer Therapie sowie das Management von Nebenwirkungen. PMID:27509439

  7. Comparison of SIFT and SURF based DEM extraction approaches on a GEOEYE-1 satellite stereo-pair

    NASA Astrophysics Data System (ADS)

    Daliakopoulos, Ioannis; Tsanis, Ioannis

    2014-05-01

    A MATLAB module for Digital Elevation Model (DEM) extraction from Very High Resolution (VHR) satellite stereo-pair imagery is used to compare the efficiency of two well established feature detection and description algorithms. A procedure for parallel processing of cascading image tiles is used for handling the large datasets requirements of VHR satellite imagery. Scale-Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF) algorithms are used to detect potentially tentative feature matches in the members of the stereo-pair. The resulting feature pairs are filtered using the RANdom SAmple Consensus (RANSAC) algorithm by using a variable distance threshold. Finally, tentative feature matches are converted to point cloud ground coordinates for DEM generation. A 0.5 m × 0.5 m Geoeye-1 stereo-pair acquired over an area of 25 km2 in the island of Crete, Greece is used as input for the module. The resulting 2 m × 2 m DEMs has superior detail over previously developed 2 m and 5 m DEMs that are used as reference, and yields a Root Mean Square Error (RMSE) of about 1 m compared to ground truth measurements. Results suggest that SURF's superior runtime performance outweighs the slightly better feature quality attained with SIFT.

  8. BOREAS HYP-8 DEM Data Over The NSA-MSA and SSA-MSA in The AEAC Projection

    NASA Technical Reports Server (NTRS)

    Knapp, David E.; Hall, Forrest G. (Editor); Wang, Xue-Wen; Band, L. E.; Smith, David E. (Technical Monitor)

    2000-01-01

    These data were derived from the original Digital Elevation Models (DEMs) produced by the Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-8 team. The original DEMs were in the Universal Transverse Mercator (UTM) projection, while this product is projected in the Albers Equal-Area Conic (AEAC) projection. The pixel size of the data is 100 meters, which is appropriate for the 1:50,000-scale contours from which the DEMs were made. The original data were compiled from information available in the 1970s and 1980s. This data set covers the two Modeling Sub-Areas (MSAs) that are contained within the Southern Study Area (SSA) and the Northern Study Area (NSA). The data are stored in binary, image format files. The DEM data over the NSA-MSA and SSA-MSA in the AEAC projection are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  9. Accuracy assessment of land cover dynamic in hill land on integration of DEM data and TM image

    NASA Astrophysics Data System (ADS)

    Li, Yunmei; Wang, Xin; Wang, Qiao; Wu, Chuanqing; Huang, Jiazhu

    2010-04-01

    To accurately assess the area of land cover in hill land, we integrated DEM data and remote sensing image in Lihe River Valley, China. Firstly, the DEM data was combined into decision tree to increase the accuracy of land cover classification. Secondly, a slope corrected model was built to transfer the projected area to surface area by DEM data. At last, the area of different land cover was calculated and the dynamic of land cover in Lihe River Valley were analyzed from 1998 to 2003. The results show that: the area of forestland increased more than 10% by the slope corrected model, that indicates the area correcting is very important for hill land; the accuracy of classification especially for forestland and garden plot is enhanced by integrating of DEM data. It can be greater than 85%. The indexes of land use extent were 266.2 in 1998, 273.1 in 2001, and 276.7 in 2003. The change rates of land use extent were 2.59 during 1998 to 2001 and 1.34 during 2001 to 2003.

  10. Validation of DEM Data Derived from World View 3 Stereo Imagery for Low Elevation Majuro Atoll, Marshall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a “massive” data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are need...

  11. Capturing Micro-topography of an Arctic Tundra Landscape through Digital Elevation Models (DEMs) Acquired from Various Remote Sensing Platforms

    NASA Astrophysics Data System (ADS)

    Vargas, S. A., Jr.; Tweedie, C. E.; Oberbauer, S. F.

    2013-12-01

    The need to improve the spatial and temporal scaling and extrapolation of plot level measurements of ecosystem structure and function to the landscape level has been identified as a persistent research challenge in the arctic terrestrial sciences. Although there has been a range of advances in remote sensing capabilities on satellite, fixed wing, helicopter and unmanned aerial vehicle platforms over the past decade, these present costly, logistically challenging (especially in the Arctic), technically demanding solutions for applications in an arctic environment. Here, we present a relatively low cost alternative to these platforms that uses kite aerial photography (KAP). Specifically, we demonstrate how digital elevation models (DEMs) were derived from this system for a coastal arctic landscape near Barrow, Alaska. DEMs of this area acquired from other remote sensing platforms such as Terrestrial Laser Scanning (TLS), Airborne Laser Scanning, and satellite imagery were also used in this study to determine accuracy and validity of results. DEMs interpolated using the KAP system were comparable to DEMs derived from the other platforms. For remotely sensing acre to kilometer square areas of interest, KAP has proven to be a low cost solution from which derived products that interface ground and satellite platforms can be developed by users with access to low-tech solutions and a limited knowledge of remote sensing.

  12. Contemporary ice-elevation changes on central Chilean glaciers using SRTM1 and high-resolution DEMs

    NASA Astrophysics Data System (ADS)

    Vivero, Sebastian; MacDonell, Shelley

    2016-04-01

    Glaciers located in central Chile have undergone significant retreat in recent decades. Whilst studies have evaluated area loss of several glaciers, there are no detailed studies of volume losses. This lack of information restricts not only estimations of current and future contributions to sea level rise, but also has limited the evaluation of freshwater resource availability in the region. Recently, the Chilean Water Directorate has supported the collection of field and remotely sensed data in the region which has enabled glacier changes to be evaluated in greater detail. This study aims to compare high-resolution laser scanning DEMs acquired by the Chilean Water Directorate in April 2015 with the recently released SRTM 1 arc-second DEM (˜30 m) acquired in February 2000 to calculate geodetic mass balance changes for three glaciers in a catchment in central Chile over a 15-year period. Detailed analysis of the SRTM and laser scanning DEMs, together with the glacier outlines enable the quantification of elevation and volume changes. Glacier outlines from February 2000 were obtained using the multispectral analysis of a Landsat TM image, whereas outlines from April 2015 were digitised from high resolution glacier orthophotomosaics. Additionally, we accounted for radar penetration into snow and/or ice by evaluating elevation differences between SRTM C-and X-bands, as well as mis-registration between SRTM DEM and the high-resolution DEMs. Over the period all glaciers show similar ice wastage in the order of 0.03 km3 for the debris-covered and non-covered glaciers. However, whilst on the non-covered glaciers mass loss is largely related to elevation and the addition of surface sediment, on the debris-covered glacier, losses are related to the development of thermokarst features. By analysing the DEM in conjunction with Landsat images, we have detected changes in the sediment cover of the non-covered glaciers, which is likely to change the behaviour of the surface mass

  13. Vertical Accuracy Assessment of 30-M Resolution Alos, Aster, and Srtm Global Dems Over Northeastern Mindanao, Philippines

    NASA Astrophysics Data System (ADS)

    Santillan, J. R.; Makinano-Santillan, M.

    2016-06-01

    The ALOS World 3D - 30 m (AW3D30), ASTER Global DEM Version 2 (GDEM2), and SRTM-30 m are Digital Elevation Models (DEMs) that have been made available to the general public free of charge. An important feature of these DEMs is their unprecedented horizontal resolution of 30-m and almost global coverage. The very recent release of these DEMs, particularly AW3D30 and SRTM- 30 m, calls for opportunities for the conduct of localized assessment of the DEM's quality and accuracy to verify their suitability for a wide range of applications in hydrology, geomorphology, archaelogy, and many others. In this study, we conducted a vertical accuracy assessment of these DEMs by comparing the elevation of 274 control points scattered over various sites in northeastern Mindanao, Philippines. The elevations of these control points (referred to the Mean Sea Level, MSL) were obtained through 3rd order differential levelling using a high precision digital level, and their horizontal positions measured using a global positioning system (GPS) receiver. These control points are representative of five (5) land-cover classes namely brushland (45 points), built-up (32), cultivated areas (97), dense vegetation (74), and grassland (26). Results showed that AW3D30 has the lowest Root Mean Square Error (RMSE) of 5.68 m, followed by SRTM-30 m (RMSE = 8.28 m), and ASTER GDEM2 (RMSE = 11.98 m). While all the three DEMs overestimated the true ground elevations, the mean and standard deviations of the differences in elevations were found to be lower in AW3D30 compared to SRTM-30 m and ASTER GDEM2. The superiority of AW3D30 over the other two DEMS was also found to be consistent even under different landcover types, with AW3D30's RMSEs ranging from 4.29 m (built-up) to 6.75 m (dense vegetation). For SRTM-30 m, the RMSE ranges from 5.91 m (built-up) to 10.42 m (brushland); for ASTER

  14. Biological activity of recombinant Der p 2, Der p 5 and Der p 7 allergens of the house-dust mite Dermatophagoides pteronyssinus.

    PubMed

    Lynch, N R; Thomas, W R; Garcia, N M; Di Prisco, M C; Puccio, F A; L'opez, R I; Hazell, L A; Shen, H D; Lin, K L; Chua, K Y

    1997-09-01

    Der p 2, Der p 5 and Der p 7 are three allergens of the house-dust mite Dermatophagoides pteronyssinus that have been cloned and expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST). We showed that these recombinant allergens produced immediate hypersensitivity skin-test reactions in 70, 60 and 52% respectively of a group of mite-sensitive allergic patients who were strongly positive to whole mite extract (WME). Comparable positivities were found for serum levels of specific IgE antibody against these allergens, as measured by the radioallergosorbant test (RAST). Overall, for the group of allergic patients that we evaluated, the serum IgE antibody concentrations against Der p 2, 5 and 7 were calculated to represent about one third, one quarter and one fifth respectively of the levels measured against the WME. However, for some patients the activity determined against the separate allergens was far higher than that detected against the WME, thus indicating that the concentration of these can be limiting in the WME. We found no significant correlations between the RAST levels against Derp 2 and either Derp 5 or 7, and RAST-inhibition tests indicated a lack of cross-reactivity between Der p 2 and the other two allergens. In contrast, the RAST results revealed the existence of a significant immunological relationship between Der p 5 and 7. Although a certain degree of reactivity against the GST fusion partner was found in the allergic patients studied, this was not a significant influence in determining the positivity against the recombinant allergens. These results confirm the in vivo biological activity of recombinant Der p 2, 5 and 7, and indicate that whilst Der p 2 is undoubtedly a major mite allergen, both Der p 5 and 7 make important contributions toward the overall allergenic activity of house-dust mites. PMID:9303332

  15. Lava flow mapping and volume calculations for the 2012-2013 Tolbachik, Kamchatka, fissure eruption using bistatic TanDEM-X InSAR

    NASA Astrophysics Data System (ADS)

    Kubanek, Julia; Richardson, Jacob A.; Charbonnier, Sylvain J.; Connor, Laura J.

    2015-12-01

    The bistatic acquisition mode of the German TanDEM-X radar satellite mission provides a reliable source for measuring morphological changes associated with volcanic activity. We present the use of this system to measure key lava flow parameters including thickness, volume, runout, and flow extent by using two TanDEM-X data pairs to generate digital elevation models (DEMs) prior to and immediately following the 2012-2013 eruption of Tolbachik Volcano, Kamchatka. Morphometric parameters and areal distribution of the new lava flow field are determined using a cell-by-cell elevation difference between the two DEMs. A total flow volume of 0.53 ± 0.07 km3, a mean flow thickness of 14.5 m, and a modal thickness of 7.8 m are calculated. We use these calculated flow parameters as input to a volume-limited lava flow emplacement model. Model simulations are able to reproduce the SW portion of the 2012-2013 Tolbachik lava flow using a 75-m Shuttle Radar Topography Mission (SRTM) DEM and the 15-m TanDEM-X derived DEM, with goodness-of-fit measures of 56.3 and 59.6 %, respectively, based on the Jaccard similarity coefficient. The flow simulation done using SRTM data underestimates the observed 14.4 km flow runout by over 3 km, while the simulation with TanDEM-X data overestimates flow runout by about 1.5 km. Performance of the lava flow modeling algorithm is highly dependent on the modal lava thickness, highlighting the importance of using TanDEM-X DEMs to provide precise lava flow measurements in order to constrain input parameters for numerical modeling of lava flows.

  16. der(16)t(1;16)/der(1;16) in breast cancer detected by fluorescence in situ hybridization is an indicator of better patient prognosis.

    PubMed

    Tsuda, H; Takarabe, T; Fukutomi, T; Hirohashi, S

    1999-01-01

    By two-color fluorescence in situ hybridization (FISH), der(16)t(1;16) or der(1;16) was frequently detected in low-grade papillary carcinoma but not in benign intraductal papilloma of the breast. In order to clarify the incidence and clinicopathological significance of der(16)t(1;16)/der(1;16) in common breast cancers, der(16)t(1;16)/der(1;16) was examined by two-color FISH in breast cancers resected from 51 patients by using DNA probes for 16cen, 16q11.2, and 1q12 labeled with biotin or digoxigenin. der(16)t(1;16)/der(1;16) was clonally detected in 16 cancers (31%), being more frequent in ductal carcinomas of lower grade and invasive lobular carcinoma than in high-grade invasive ductal carcinoma (P<0.001). der(16)t(1;16)/der(1;16) was also correlated with a higher amount of hormone receptors in the tumor (P<0.05). Disease-free and overall survival rates of the patient group with der(16)t(1;16)/der(1;16)-positive cancer were higher (88% and 94%) than those of the group with der(16)t(1;16)/der(1; 16)-negative cancer (39% and 68%) (P<0.05). Among the 16 patients with lymph node metastasis who received one of two similar forms of postsurgical adjuvant chemo-endocrine therapy, the prognosis of those with der(16)t(1;16)/der(1;16)-positive cancer was better than that of those with der(16)t(1;16)/der(1;16)-negative cancer (P<0.05). der(16)t(1;16)/der(1;16) detected by FISH is considered helpful in identifying patients with a better prognosis and for stratification of patients in randomized clinical trials of adjuvant chemo-endocrine therapies. PMID:9892111

  17. van der Waals Heterostructures Grown by MBE

    NASA Astrophysics Data System (ADS)

    Hinkle, Christopher

    In this work, we demonstrate the high-quality MBE heterostructure growth of various layered 2D materials by van der Waals epitaxy (VDWE). The coupling of different types of van der Waals materials including transition metal dichalcogenide thin films (e.g., WSe2, WTe2, HfSe2) , insulating hexagonal boron nitride (h-BN), and topological insulators (e.g., Bi2Se3) allows for the fabrication of novel electronic devices that take advantage of unique quantum confinement and spin-based characteristics. The relaxed lattice-matching criteria of van der Waals epitaxy has allowed for high-quality heterostructure growth with atomically abrupt interfaces, allowing us to couple these materials based primarily on their band alignment and electronic properties. We will discuss the impact of sample preparation, surface reactivity, and lattice mismatch of various substrates (sapphire, graphene, TMDs, Bi2Se3) on the growth mode and quality of the films and will discuss our studies of substrate temperature and flux rates on the resultant growth and grain size. Structural and chemical characterization was conducted via reflection high energy electron diffraction (RHEED, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning tunneling microscopy/spectroscopy (STM/S), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Experimentally determined band alignments have been determined and compared with first-principles calculations allowing the design of novel low-power logic and magnetic memory devices. Initial results from the electrical characterization of these grown thin films and some simple devices will also be presented. These VDWE grown layered 2D materials show significant potential for fabricating novel heterostructures with tunable band alignments and magnetic properties for a variety of nanoelectronic and optoelectronic applications.

  18. <5cm Ground Resolution DEMs for the Atacama Fault System (Chile), Acquried With the Modular Airborne Camera System (MACS)

    NASA Astrophysics Data System (ADS)

    Zielke, O.; Victor, P.; Oncken, O.; Bucher, T. U.; Lehmann, F.

    2011-12-01

    A primary step towards assessing time and size of future earthquakes is the identification of earthquake recurrence patterns in the existing seismic record. Geologic and geomorphic data are commonly analyzed for this purpose, reasoned by the lack of sufficiently long historical or instrumental seismic data sets. Until recently, those geomorphic data sets encompassed field observation, local total station surveys, and aerial photography. Over the last decade, LiDAR-based high-resolution topographic data sets became an additional powerful mean, contributing distinctly to a better understanding of earthquake rupture characteristics (e.g., single-event along-fault slip distribution, along-fault slip accumulation pattern) and their relation to fault geometric complexities. Typical shot densities of such data sets (e.g., airborne-LiDAR data along the San Andreas Fault) permit generation of digital elevation models (DEM) with <50 cm ground resolution, sufficient for depiction of meter-scale tectonic landforms. Identification of submeter-scale features is however prohibited by DEM resolution limitation. Here, we present a high-resolution topographic and visual data set from the Atacama fault system near Antofagasta, Chile. Data were acquired with Modular Airborne Camera System (MACS) - developed by the DLR (German Aerospace Center) in Berlin, Germany. The photogrammetrically derived DEM and True Ortho Images with <5cm ground resolution permit identification of very small-scale geomorphic features, thus enabling fault zone and earthquake rupture characterization at unprecedented detail. Compared to typical LiDAR-DEM, ground resolution is increased by an order of magnitude while the spatial extend of these data set is essentially the same. Here, we present examples of the <5cm resolution data set (DEM and visual results) and further explore resolution capabilities and potential with regards to the aforementioned tectono-geomorphic questions.

  19. Crystal Structures of Mite Allergens Der f 1 and Der p 1 Reveal Differences in Surface-Exposed Residues that May Influence Antibody Binding

    SciTech Connect

    Chruszcz, Maksymilian; Chapman, Martin D.; Vailes, Lisa D.; Stura, Enrico A.; Saint-Remy, Jean-Marie; Minor, Wladek; Pomés, Anna

    2009-12-01

    The Group 1 mite allergens, Der f 1 and Der p 1, are potent allergens excreted by Dermatophagoides farinae and Dermatophagoides pteronyssinus, respectively. The human IgE antibody responses to the Group 1 allergens show more cross-reactivity than the murine IgG antibody responses which are largely species-specific. Here, we report the crystal structure of the mature form of Der f 1, which was isolated from its natural source, and a new, high-resolution structure of mature recombinant Der p 1. Unlike Der p 1, Der f 1 is monomeric both in the crystalline state and in solution. Moreover, no metal binding is observed in the structure of Der f 1, despite the fact that all amino acids involved in Ca{sup 2+} binding in Der p 1 are completely conserved in Der f 1. Although Der p 1 and Der f 1 share extensive sequence identity, comparison of the crystal structures of both allergens revealed structural features which could explain the differences in murine and human IgE antibody responses to these allergens. There are structural differences between Der f 1 and Der p 1 which are unevenly distributed on the allergens' surfaces. This uneven spatial arrangement of conserved versus altered residues could explain both the specificity and cross-reactivity of antibodies against Der f 1 and Der p 1.

  20. Physik gestern und heute: Visualisierung mit der Schlierenmethode

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-07-01

    Der Name des österreichischen Forschers Ernst Mach ist heute noch mit der Schallgeschwindigkeit verbunden. Diese Auszeichnung resultiert aus Machs Untersuchungen, wie sich Projektile mit Überschallgeschwindigkeit durch die Luft bewegen. Gerade in jüngster Zeit hat die Anwendung derartiger Methoden durch technische Modifikationen wieder einen Aufschwung erfahren.

  1. Endoskopie, minimal invasive chirurgische und navigierte Verfahren in der Urologie

    NASA Astrophysics Data System (ADS)

    Grosse, Joachim; von Walter, Matthias; Jakse, Gerhard

    Betrachtet man die letzten 100 Jahre der Urologie in Deutschland seit Gründung ihrer Fachgesellschaft 1906 in Stuttgart, so sind sicherlich die letzten 25 Jahre von umfassenden Entwicklungen mit z. T. vollständigen Umwälzungen bisheriger Therapien und Methoden auf urologischen Fachgebiet gekennzeichnet. In erster Linie handelte es sich dabei um minimal invasive endoskopische Techniken wie perkutane Nierenchirurgie, Ureterorenoskopie, videoendoskopisch unterstütze transurethrale Elektroresektionen der Prostata und von Blasentumore sowie die Laparoskopie. Sie führten zu besseren operativen Ergebnissen und einer deutlichen Senkung der Morbidität der entsprechenden Behandlung urologischer Krankheitsbilder, mit der Konsequenz, dass einige bisher als Standard gültige offene Operationsverfahren abgelöst wurden.

  2. Fast 3D-EM reconstruction using Planograms for stationary planar positron emission mammography camera.

    PubMed

    Motta, A; Guerra, A Del; Belcari, N; Moehrs, S; Panetta, D; Righi, S; Valentini, D

    2005-12-01

    At the University of Pisa we are building a PEM prototype, the YAP-PEM camera, consisting of two opposite 6 x 6 x 3 cm3 detector heads of 30 x 30 YAP:Ce finger crystals, 2 x 2 x 30 mm3 each. The camera will be equipped with breast compressors. The acquisition will be stationary. Compared with a whole body PET scanner, a planar Positron Emission Mammography (PEM) camera allows a better, easier and more flexible positioning around the breast in the vicinity of the tumor: this increases the sensitivity and solid angle coverage, and reduces cost. To avoid software rejection of data during the reconstruction, resulting in a reduced sensitivity, we adopted a 3D-EM reconstruction which uses all of the collected Lines Of Response (LORs). This skips the PSF distortion given by data rebinning procedures and/or Fourier methods. The traditional 3D-EM reconstruction requires several times the computation of the LOR-voxel correlation matrix, or probability matrix {p(ij)}; therefore is highly time-consuming. We use the sparse and symmetry properties of the matrix {p(ij)} to perform fast 3D-EM reconstruction. Geometrically, a 3D grid of cubic voxels (FOV) is crossed by several divergent 3D line sets (LORs). The symmetries occur when tracing different LORs produces the same p(ij) value. Parallel LORs of different sets cross the FOV in the same way, and the repetition of p(ij) values depends on the ratio between the tube and voxel sizes. By optimizing this ratio, the occurrence of symmetries is increased. We identify a nucleus of symmetry of LORs: for each set of symmetrical LORs we choose just one LOR to be put in the nucleus, while the others lie outside. All of the possible p(ij) values are obtainable by tracking only the LORs of this nucleus. The coordinates of the voxels of all of the other LORs are given by means of simple translation rules. Before making the reconstruction, we trace the LORs of the nucleus to find the intersecting voxels, whose p(ij) values are computed and

  3. The accuracy of photo-based structure-from-motion DEMs

    NASA Astrophysics Data System (ADS)

    James, M. R.; Robson, S.

    2012-04-01

    Data for detailed digital elevation models (DEMs) are usually collected by expensive laser-based techniques, or by photogrammetric methods that require expertise and specialist software. However, recent advances in computer vision research now permit 3D models to be automatically derived from unordered collections of photographs, offering the potential for significantly cheaper and quicker DEM production. Here, we assess the accuracy of this approach for geomorphological applications using examples from a coastal cliff and a volcanic edifice. The reconstruction process is based on a combination of structure-from-motion and multi-view stereo algorithms (SfM-MVS). Using multiple photographs of a scene taken from different positions with a consumer-grade camera, dense point clouds (millions of points) can be derived. Processing is carried out by automated 'reconstruction pipeline' software downloadable from the internet, e.g. http://blog.neonascent.net/archives/bundler-photogrammetry-package/. Unlike traditional photogrammetric approaches, the initial reconstruction process does not require the identification of any control points or initial camera calibration and is carried out with little or no operator intervention. However, such reconstructions are initally un-scaled and un-oriented so additional software (http://www.lancs.ac.uk/staff/jamesm/software/sfm_georef.htm) has been developed to permit georeferencing. Although this step requires the presence of some control points or features within the scene, it does not have the relatively strict image acquisition and control requirements of traditional photogrammetry. For accuracy, and to allow error analysis, georeferencing observations are made within the image set, rather than requiring feature matching within the point cloud. In our coastal example, 133 photos taken with a Canon EOS 450D and 28 mm prime lens, from viewing distances of ~20 m, were used to reconstruct a ~60 m long section of eroding cliff. The

  4. Van der Waals heterostructures and devices

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Weiss, Nathan O.; Duan, Xidong; Cheng, Hung-Chieh; Huang, Yu; Duan, Xiangfeng

    2016-09-01

    Two-dimensional layered materials (2DLMs) have been a central focus of materials research since the discovery of graphene just over a decade ago. Each layer in 2DLMs consists of a covalently bonded, dangling-bond-free lattice and is weakly bound to neighbouring layers by van der Waals interactions. This makes it feasible to isolate, mix and match highly disparate atomic layers to create a wide range of van der Waals heterostructures (vdWHs) without the constraints of lattice matching and processing compatibility. Exploiting the novel properties in these vdWHs with diverse layering of metals, semiconductors or insulators, new designs of electronic devices emerge, including tunnelling transistors, barristors and flexible electronics, as well as optoelectronic devices, including photodetectors, photovoltaics and light-emitting devices with unprecedented characteristics or unique functionalities. We review the recent progress and challenges, and offer our perspective on the exploration of 2DLM-based vdWHs for future application in electronics and optoelectronics.

  5. Toward a simple, DEM-based model for linking channel morphology with Atlantic salmon habitat

    NASA Astrophysics Data System (ADS)

    Snyder, N. P.; Wilkins, B. C.; Wright, J. R.

    2008-12-01

    Atlantic salmon require swiftwater gravel-bedded rivers for rearing and spawning. Morphology of the rivers in coastal New England and Atlantic Canada is strongly influenced by glacial and land-use history. Longitudinal profiles are characterized by relatively steep (gradient >0.002) and flat (gradient <0.0005) segments, with length scales of several km. This heterogeneity corresponds to strong variations in channel form (boulder cascades, pools and riffles, plane beds, low-gradient wetlands, mainstem lakes), substrate grain size, and aquatic habitat characteristics. We seek to develop methods to use simple GIS-based measurements to investigate relationships between channel processes and habitat characteristics. The near extirpation of Atlantic salmon from U.S. rivers motivates restoration efforts, including the removal of barriers to migration and instream habitat restoration projects. Resource managers desire GIS-based methods to facilitate rapid identification of potential spawning and rearing habitat within channel networks. We develop methods for predicting channel conditions using traditional (10-30 m pixels) and lidar (1-m pixels) digital elevation models (DEMs). We calibrate and test our methods using field surveys of habitat, channel form and bed grain size in coastal Maine and New Brunswick. A statistical approach uses stream gradient measured over segments defined by channel centerline intersections with contour lines (3-6 m intervals) on digitized topographic maps, contributing area, and physiographic province. This model explains 73% of the variation in field-identified rearing habitat. Commonly available GIS data allows this model to be applied over large areas, making it useful for regional habitat assessments. We present preliminary results from a process- based model that predicts bed grain size using morphologic measurements from lidar DEMs and the Shields equation. We compare these predictions to field grain size and habitat mapping. The lidar

  6. Creation of a Multiresolution and Multiaccuracy Dtm: Problems and Solutions for Heli-Dem Case Study

    NASA Astrophysics Data System (ADS)

    Biagi, L.; Carcano, L.; Lucchese, A.; Negretti, M.

    2013-01-01

    The work is part of "HELI-DEM" (HELvetia-Italy Digital Elevation Model) project, funded by the European Regional Development Fund within the Italy-Switzerland cooperation program. The aim of the project is the creation of a unique DTM for the alpine and subalpine area between Italy (Piedmont, Lombardy) and Switzerland (Ticino and Grisons Cantons); at present, different DTMs, that are in different reference frames and have been obtained with different technologies, accuracies, and resolutions, have been acquired. The final DTM should be correctly georeferenced and produced validating and integrating the data that are available for the project. DTMs are fundamental in hydrogeological studies, especially in alpine areas where hydrogeological risks may exist. Moreover, when an event, like for example a landslide, happens at the border between countries, a unique and integrated DTM which covers the interest area is useful to analyze the scenario. In this sense, HELI-DEM project is helpful. To perform analyses along the borders between countries, transnational geographic information is needed: a transnational DTM can be obtained by merging regional low resolution DTMs. Moreover high resolution local DTMs should be used where they are available. To be merged, low and high resolution DTMs should be in the same three dimensional reference frame, should not present biases and should be consistent in the overlapping areas. Cross-validation between the different DTMs is therefore needed. Two different problems should be solved: the merging of regional, partly overlapping low and medium resolution DTMs into a unique low/medium resolution DTM and the merging with other local high resolution/high accuracy height data. This paper discusses the preliminary processing of the data for the fusion of low and high resolution DTMs in a study-case area within the Lombardy region: Valtellina valley. In this region the Lombardy regional low resolution DTM is available, with a horizontal

  7. Die qualitätskontrolle als hilfsmittel zur festlegung der produktionsparameter bei der herstellung von lwr-brennstoffen

    NASA Astrophysics Data System (ADS)

    Sondermann, T.

    1982-04-01

    ZusammenfassungDer bekannte Vorteil des AUC-Verfahrens, ein UO 2-Pulver zu liefern, das ohne Zwischenschritte direkt zu Tabletten verpreβt werden kann, geht mit einer weiteren, weniger bekannten positiven Eigenschaft einher: Mit der Wahl der Produktionsparameter bei der UO 2-Pulverherstellung können die Qualitätsmerkmale der Brennstofftabletten direkt gesteuert werden. Wie umfangreiche Untersuchungen gezeigt haben, besteht ein mathematisch formulierbarer Zusammenhang zwischen den Produktionsparametern und den Pulver-bzw. Tablettenqualitäten. Das so erhaltene mathematische Modell gestattet es nun, exakt die Produktionsparameter einzustellen, die zur gewünschten Qualität führen, wobei gleichzeitig die wirtschaftliche Fahrweise gewählt werden kann.

  8. Application of CryoSat-2 data product for DEM generation in Dome-A summit area, Antarctica

    NASA Astrophysics Data System (ADS)

    fang, W.; Cheng, X.; Hui, F.

    2012-12-01

    Currently available Digital Elevation Models (DEMs) of Dome A were originally derived from radar altimetry data (ERS-1/2, GLAS/ICESat), and later improved by GPS measurements. The relatively low resolution and coverage poses a problem, especially for the regional research. CryoSat-2 with SIRAL (SAR/Interferometric Altimeter) was launched on 8 April 2010, providing an alternative for high-density and high-accuracy acquisition of terrain point data. The inclination of the satellite's orbit is 92°, and the orbit can approach latitude of 88°. The repeat period of 369 days provides a high orbit crossover density (10 crossovers km-2 year-1 at 87°) with a 30-day sub-cycle. In this study, we collected ten months (March to December 2011) of successive CryoSat-2 Low Rate Mode level 2 (LRM L2) datasets. Two types of filters were applied to remove additional elevation outliers. These filtering procedures excluded 5.95% of the original data. According to the distribution of the point data, terrain modeling of grid DEM, interpolation method of Kriging (ordinary Kriging), and a grid resolution of 200m is chosen for DEM generation in this study. Finally, we used the satellite's monthly revisits with non-repeated coverage and present a novel DEM of 900 km2 in the Dome A region centered at Kunlun Station (80°25‧01″S, 77°06‧58″E). It shows that the topography of the Dome A region is saddle-shaped, with a northern peak and a southern peak. We used a subtraction method to compare the novel DEM with the previous DEM of GPS measurements. The elevation differences exhibit a positive average elevation bias. It may be due to the penetration of the Ku-band radar wave into the soft snow. As a first approximation based on the statistics of the height differences, we estimate that the average penetration depth of the CryoSat-2 Ku-band wave in this area is 1 m. Map of surface topography over the Dome A region generated from CryoSat-2 data. Contours are smoothed. The contour interval

  9. Influence of the external DEM on PS-InSAR processing and results on Northern Appennine slopes

    NASA Astrophysics Data System (ADS)

    Bayer, B.; Schmidt, D. A.; Simoni, A.

    2014-12-01

    We present an InSAR analysis of slow moving landslide in the Northern Appennines, Italy, and assess the dependencies on the choice of DEM. In recent years, advanced processing techniques for synthetic aperture radar interferometry (InSAR) have been applied to measure slope movements. The persistent scatterers (PS-InSAR) approach is probably the most widely used and some codes are now available in the public domain. The Stanford method of Persistent Scatterers (StamPS) has been successfully used to analyze landslide areas. One problematic step in the processing chain is the choice of an external DEM that is used to model and remove the topographic phase in a series of interferograms in order to obtain the phase contribution caused by surface deformation. The choice is not trivial, because the PS InSAR results differ significantly in terms of PS identification, positioning, and the resulting deformation signal. We use four different DEMs to process a set of 18 ASAR (Envisat) scenes over a mountain area (~350 km2) of the Northern Appennines of Italy, using StamPS. Slow-moving landslides control the evolution of the landscape and cover approximately 30% of the territory. Our focus in this presentation is to evaluate the influence of DEM resolution and accuracy by comparing PS-InSAR results. On an areal basis, we perform a statistical analysis of displacement time-series to make the comparison. We also consider two case studies to illustrate the differences in terms of PS identification, number and estimated displacements. It is clearly shown that DEM accuracy positively influences the number of PS, while line-of-sight rates differ from case to case and can result in deformation signals that are difficult to interpret. We also take advantage of statistical tools to analyze the obtained time-series datasets for the whole study area. Results indicate differences in the style and amount of displacement that can be related to the accuracy of the employed DEM.

  10. DEM simulation of undrained behaviour with preshearing history for saturated granular media

    NASA Astrophysics Data System (ADS)

    Gong, Guobin; Zha, Xiaoxiong

    2013-03-01

    This paper presents the results of the three-dimensional (3D) discrete element method (DEM) simulations of undrained axisymmetric/triaxial tests on loose assemblies of polydisperse spheres with and without preshearing history using a periodic cell. Undrained tests are modelled by deforming the samples under constant volume conditions. The simulations show that the preshearing process will not induce initial structural anisotropy, and that the presheared and unpresheared samples follow the same initial stress path along a unique limiting boundary in the q-p space, as observed in the published experimental literature, which was not crossed over by any of the stress paths of the presheared samples. It is also shown that the presheared samples are denser compared with the original unpresheared one, and therefore exhibit higher resistance to (temporary) liquefaction. At the grain scale, such higher resistance is found to be attributed to the evolution of a redundancy factor, a microscopic definition of liquefaction (temporary liquefaction). The Lade instability (peak deviator stress) is found to correspond to a unique mechanical coordination number of 4.5, independent of preshearing history. It is also found that the onset of liquefaction (temporary liquefaction) in terms of the redundancy factor lags behind the onset of macroscopic strain softening in terms of the Lade instability for the presheared and unpresheared samples under undrained conditions.

  11. Classification of topography using DEM data and its correlation with the geology of Greece

    NASA Astrophysics Data System (ADS)

    Zargli, Eleni; Liodakis, Stelios; Kyriakidis, Phaedon; Savvaidis, Alexandros

    2013-08-01

    Continuous topography from Digital Elevation Model (DEM) data is frequently segmented into terrain classes based on local morphological characteristics of terrain elevation, e.g., local slope gradient and convexity. The resulting classes are often used as proxies for the average shear wave velocity up to 30 m, and the determination of ground types as required by the Eurocode (EC8) for computing elastic design spectra. In this work, we investigate the links between terrain related variables, particularly slope gradient, extracted for the area of Greece from the Shuttle Radar Topography Mission (SRTM) 30 arc second global topographic data available from the United States Geological Survey (USGS), with: (a) the global terrain classification product of Iwahashi and Pike (2007) in which 16 terrain types are identified for the same spatial resolution, and (b) information on geological units extracted at the same resolution from the geological map of Greece at a scale of 1/500000 as published from the Institute of Geology and Mineral Exploration (IGME). An interpretation of these links is presented within the context of understanding the reliability of using geology, slope and terrain classes for site characterizations of earthquake risk in a high seismicity area like Greece. Our results indicate that slope is a somewhat biased proxy for solid rocks, whereas in Alluvial deposits the distance to and type of the nearest geological formation appears to provide qualitative information on the size of the sedimentary deposit.

  12. Astronomical solar radiation simulation based on DEM in Wuyishan mountainous areas

    NASA Astrophysics Data System (ADS)

    Wang, Shaogang; He, Guojin; Liu, Dingsheng; Wang, Xiaoqin

    2008-12-01

    Digital Elevation Models (DEM) data (90mx90m) reflected by the NASA Shuttle Radar Topography Mission (SRTM) are used as basic information source to overlay digital slope models and digital aspect models, which are applicable to the mountainous terrain of astronomical solar radiation distributed model. This paper uses ray-tracing method and integral by subparagraph to calculate the conditions of terrain shading information, and through an integral way to make a visualization of monthly astronomical solar radiation (ASR). The result shows that the geographical and topographical factors do visible effect to the spatial distribution of astronomical solar radiation over Wuyishan area, especially in January, it does the most obvious effect to terrain shading, while in July it does the lightest effect to terrain shading. This method can accurately reflect regional differences of solar radiation, and through accumulating daily solar radiation in the region, we can obtain the total amount of solar radiation in every month of the year. This result can provide prerequisite conditions as an important reference and then be useful to biomass estimating of vegetation, agricultural production, climatic resources development and exploiture.

  13. Phenological tracking og agricultural feilds investigated by using dual polarimetry tanDEM-X images

    NASA Astrophysics Data System (ADS)

    Mirzaee, S.; Motagh, M.; Arefi, H.; Nooryazdan, A.

    2015-04-01

    Remote sensing plays a key role in monitoring and assessing environmental changes. Because of its special imaging characteristics such as high-resolution, capabilities to obtain data in all weather conditions and sensitivity to geometrical and dielectric properties of the features, Synthetic Aperture Radar (SAR) technology has become a powerful technique to detect small scale changes related to earth surface.SAR images contain the information of both phase and intensity in different modes like single, dual and full polarimetric states which are important in order to extract information about various targets. In this study we investigate phenological changes in an agricultural region using high-resolution X-band SAR data. The case study is located in Doroud region of Lorestan province, west of Iran. The purpose is to investigate the ability of copolar and interferometric coherence extracted from TanDEM-X dual polarimetry (HH/VV) in bistatic StripMap mode for tracking the phenological changes of crops during growing season. The data include 11 images acquired between 12.06.2012 and 02.11.2012 and 6 images acquired between 30.05.2013 and 04.08.2013 in the CoSSC format. Results show that copolar coherence is almost able to follow phenological changes but interferometric coherence has a near constant behaviour with fluctuations mainly related to baseline variations.

  14. New insights into high resolution DEM structural analysis with Coltop3D software

    NASA Astrophysics Data System (ADS)

    Metzger, R.; Jaboyedoff, M.; Oppikofer, T.

    2009-04-01

    Modern measurement devices such a terrestrial laser scanning (TLS) systems allow for collecting tremendous amount of (x,y,z) points (up to 20 millions) within a few minutes. However, data analysis still may be impaired because of software limitations, which are usually not designed to handle such huge data sets. To overcome this shortcoming, a software - Coltop3D - was written from scratch. Coltop3D aims at providing the geosciences community a powerful tool to visually handle seamlessly large point clouds and large regular grids DEM, at allowing for straightforward visual analysis of the data with different colour scheme, and at providing specific geologist and/or geoscientist treatment methods such as structural analysis. The main features of Coltop3D are as follow: 1) Ability to handle huge data sets (up to 150 millions points); 2) Coloring the surface with a color scheme linking computer graphics HSV wheel and Schmidt-Lambert stereonet projection; 3) Ability to select a subset of a point cloud with complex geometric shapes; 4) Ability to select a subset of a point cloud with dip and dip direction values; 5) Creating density stereonets with selected subset; 6) Easily import from or export point cloud data to third party software. Besides the technical and basic capabilities of Coltop3D, specific case studies such as structural analysis and rock fall analysis will be presented.

  15. The value of a UAV-acquired DEM for flood inundation mapping and modeling

    NASA Astrophysics Data System (ADS)

    Schumann, Guy J.-P.; Muhlhausen, Joseph; Andreadis, Konstantinos

    2016-04-01

    Remotely Piloted Systems also known as Unmanned Aerial Vehicle have rapidly developed as tools for remote sensing and mapping and publications referring to RPS remote sensing applications is increasing each year. In particular Structure from Motion (SfM), a relatively new photogrammetry approach has been documented for various applications. Some papers have focused on the accuracy of the output generated by SfM by validating relative and absolute accuracy using ground control points, others have looked at various applications. Yet we argue that a major aspect of SfM has been overlooked, its ability to generate highly accurate point cloud models without the use of ground control points. We demonstrate this by comparing with a LIDAR DEM, a dataset which has been transformative in flood inundation research and applications. Our results demonstrate that a point cloud collected using a RPS and a 16M pixel Bayer sensor camera using a rolling shutter can achieve a RMSE of 39 cm compared to LIDAR. We conclude that a SfM model is not only highly accurate but could complement LIDAR for floodplain mapping and modelling, especially in cases where smaller coverage is sufficient and LiDAR acquisition via airplane may be too costly or impractical.

  16. New DEMs may stimulate significant advancements in remote sensing of soil moisture

    NASA Astrophysics Data System (ADS)

    Nolan, Matt; Fatland, Dennis R.

    From Napoleon's defeat at Waterloo to increasing corn yields in Kansas to greenhouse gas flux in the Arctic, the importance of soil moisture is endemic to world affairs and merits the considerable attention it receives from the scientific community. This importance can hardly be overstated, though it often goes unstated.Soil moisture is one of the key variables in a variety of broad areas critical to the conduct of societies' economic and political affairs and their well-being; these include the health of agricultural crops, global climate dynamics, military trafficability planning, and hazards such as flooding and forest fires. Unfortunately the in situ measurement of the spatial distribution of soil moisture on a watershed-scale is practically impossible. And despite decades of international effort, a satellite remote sensing technique that can reliably measure soil moisture with a spatial resolution of meters has not yet been identified or implemented. Due to the lack of suitable measurement techniques and, until recently digital elevation models (DEMs), our ability to understand and predict soil moisture dynamics through modeling has largely remained crippled from birth [Grayson and Bloschl, 200l].

  17. Mapping Landslides in Lunar Impact Craters Using Chebyshev Polynomials and Dem's

    NASA Astrophysics Data System (ADS)

    Yordanov, V.; Scaioni, M.; Brunetti, M. T.; Melis, M. T.; Zinzi, A.; Giommi, P.

    2016-06-01

    Geological slope failure processes have been observed on the Moon surface for decades, nevertheless a detailed and exhaustive lunar landslide inventory has not been produced yet. For a preliminary survey, WAC images and DEM maps from LROC at 100 m/pixels have been exploited in combination with the criteria applied by Brunetti et al. (2015) to detect the landslides. These criteria are based on the visual analysis of optical images to recognize mass wasting features. In the literature, Chebyshev polynomials have been applied to interpolate crater cross-sections in order to obtain a parametric characterization useful for classification into different morphological shapes. Here a new implementation of Chebyshev polynomial approximation is proposed, taking into account some statistical testing of the results obtained during Least-squares estimation. The presence of landslides in lunar craters is then investigated by analyzing the absolute values off odd coefficients of estimated Chebyshev polynomials. A case study on the Cassini A crater has demonstrated the key-points of the proposed methodology and outlined the required future development to carry out.

  18. Numerical modelling by the Stokes--DEM coupled simulation for a roof at hot magma chamber

    NASA Astrophysics Data System (ADS)

    Furuichi, M.; Nishiura, D.

    2014-12-01

    The dynamics of a granular media has been suggested to play an important role in a reheated magma chamber by a hot intrusion (e.g. Burgisser and Bergantz, 2011). Although several mechanisms, such as Rayleigh Taylor instability, unzipping, and rhythmic convection (e.g. Shibano et.al. 2012, 2013), have been proposed for characterizing upward migration process in a crystalline magma chamber, their contributions in the long geodynamical time scale are not clear yet. Thus we perform numerical simulations to investigate the thermal evolution of the magma chamber with basal intrusion in three dimensions. In order to solve high-viscosity fluid and particle dynamics for modelling a melt--crystal jammed state of the magma, we have developed a coupled Stokes--DEM simulation code with two key techniques: formulation of particle motion without inertia and semi-implicit treatment of particle motion in the fluid equation (Furuichi and Nishiura 2014). Our simulation can successfully handle sinking particles in a high-viscosity fluid. We examine different types of the granular media heated from the bottom with varying parameters. We especially focus on pattern of the settling particles against the melt density contrast between upper and lower region.

  19. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    SciTech Connect

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  20. Cooperative dynamics of a group of intruders subsiding in granular media: A DEM study

    NASA Astrophysics Data System (ADS)

    Goey, Cher Hui; Wu, Chuan-Yu

    2013-06-01

    We numerically investigated the subsidence of a group of solid intruders in a randomly generated granular bed using discrete element method (DEM) in 2D and explored the cooperative behaviour of these intruders. Five intruders with a specified separation distance were placed on the surface of the granular bed and released to subside with zero impact velocity. Dynamics of the intruders was analysed. In addition, the effects of friction, boundary constraints, and the diameter and density ratio of the intruders to particles in the granular bed on the cooperative dynamics were also examined. It was found that friction and boundary constraints significantly affected the subsiding kinematics of the intruders. Most interestingly, it was shown that the intruders subside in a cooperative manner as they initially split from each other, and then move toward each other, resembling the flying pattern of a flock of birds in the air. This cooperative behaviour is in broad agreement with the experimental observations of Pacheco-Vazquez and Ruiz-Suarez (2010).

  1. Satellite-derived Digital Elevation Model (DEM) selection, preparation and correction for hydrodynamic modelling in large, low-gradient and data-sparse catchments

    NASA Astrophysics Data System (ADS)

    Jarihani, Abdollah A.; Callow, John N.; McVicar, Tim R.; Van Niel, Thomas G.; Larsen, Joshua R.

    2015-05-01

    Digital Elevation Models (DEMs) that accurately replicate both landscape form and processes are critical to support modelling of environmental processes. Topographic accuracy, methods of preparation and grid size are all important for hydrodynamic models to efficiently replicate flow processes. In remote and data-scarce regions, high resolution DEMs are often not available and therefore it is necessary to evaluate lower resolution data such as the Shuttle Radar Topography Mission (SRTM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for use within hydrodynamic models. This paper does this in three ways: (i) assessing point accuracy and geometric co-registration error of the original DEMs; (ii) quantifying the effects of DEM preparation methods (vegetation smoothed and hydrologically-corrected) on hydrodynamic modelling relative accuracy; and (iii) quantifying the effect of the hydrodynamic model grid size (30-2000 m) and the associated relative computational costs (run time) on relative accuracy in model outputs. We initially evaluated the accuracy of the original SRTM (∼30 m) seamless C-band DEM (SRTM DEM) and second generation products from the ASTER (ASTER GDEM) against registered survey marks and altimetry data points from the Ice, Cloud, and land Elevation Satellite (ICESat). SRTM DEM (RMSE = 3.25 m,) had higher accuracy than ASTER GDEM (RMSE = 7.43 m). Based on these results, the original version of SRTM DEM, the ASTER GDEM along with vegetation smoothed and hydrologically corrected versions were prepared and used to simulate three flood events along a 200 km stretch of the low-gradient Thompson River, in arid Australia (using five metrics: peak discharge, peak height, travel time, terminal water storage and flood extent). The hydrologically corrected DEMs performed best across these metrics in simulating floods compared with vegetation smoothed DEMs and original DEMs. The response of model performance to grid size was non

  2. Der f 21, a novel allergen from dermatophagoides farina.

    PubMed

    Wu, Yulan; Jiang, Congli; Li, Meng; Yu, Haiqiong; Xiao, Xiaojun; Fan, Xiaoqin; Lin, Jianli; Liu, Xiaoyu; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2016-01-01

    The Dermatophagoides farina (D. farina) allergens are an important factor contributing to allergic disease. To identify new allergens is important for diagnosis and treatment of allergic diseases. In this study, we sought to characterize the biological activity of Der f 21 of D. farina. The recombinant Der f 21 protein was characterized by western-blot, ELISA and Skin prick test using clinic patient's serum.An allergic asthma mouse model was established with the rDer f 21 as a specific antigen. The results showed that the sera from 28.9% in 38 dust mite allergic children displayed positive results in response to rDer f 21, and 42% in 98 dust mite allergic patients displayed positive response in skin prick test. In addition, Immune inhibition assays showed there was IgE cross-reactivity between rDer f 21 and rDer f 5. Moreover, an allergic asthma mouse model was established. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice, interleukin-4(IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased in the allergic mice. The results demonstrate that Der f 21 is a novel allergen.

  3. Development of a coupled discrete element (DEM)-smoothed particle hydrodynamics (SPH) simulation method for polyhedral particles

    NASA Astrophysics Data System (ADS)

    Nassauer, Benjamin; Liedke, Thomas; Kuna, Meinhard

    2016-03-01

    In the present paper, the direct coupling of a discrete element method (DEM) with polyhedral particles and smoothed particle hydrodynamics (SPH) is presented. The two simulation techniques are fully coupled in both ways through interaction forces between the solid DEM particles and the fluid SPH particles. Thus this simulation method provides the possibility to simulate the individual movement of polyhedral, sharp-edged particles as well as the flow field around these particles in fluid-saturated granular matter which occurs in many technical processes e.g. wire sawing, grinding or lapping. The coupled method is exemplified and validated by the simulation of a particle in a shear flow, which shows good agreement with analytical solutions.

  4. Tunnelling in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Mishchenko, Artem; Novoselov, Kostya; Geim, Andre; Eaves, Laurence; Falko, Vladimir

    When graphene and other conductive two-dimensional (2D) materials are separated by an atomically thin insulating 2D crystal, quantum mechanical tunnelling leads to appreciable current between two 2D conductors due to the overlap of their wavefunctions. These tunnel devices demonstrate interesting physics and potential for applications: such effects as resonant tunnelling, negative differential conductance, light emission and detection have already been demonstrated. In this presentation we will outline the current status and perspectives of tunnelling transistors based on 2D materials assembled into van der Waals heterostructures. Particularly, we will present results on mono- and bilayer graphene tunnelling, tunnelling in 2D crystal-based quantum wells, and tunnelling in superconducting 2D materials. Such effects as momentum and chirality conservation, phonon- and impurity-assisted tunnelling will also be discussed. Finally, we will ponder the implications of discovered effects for practical applications.

  5. Effect of DEM source on equivalent Horton-Strahler ratio based GIUH for catchments in two Indian river basins

    NASA Astrophysics Data System (ADS)

    Chavan, Sagar Rohidas; Srinivas, V. V.

    2015-09-01

    Horton-Strahler (H-S) concept has been extensively used for quantification of characteristics of a stream network since several decades. The quantified values are often sensitive to threshold area specified for initiation of streams to demarcate the network, and to the position of outlet of a catchment. This implies that inferences drawn based on derived characteristics for a stream network are likely to be inconsistent, which is undesirable. To address this, a strategy based on self-similarity properties of channel network was proposed recently by Moussa (2009), which involves estimation of equivalent H-S ratios using catchment shape descriptors that are independent of threshold area. This study investigates effectiveness of the strategy on 42 catchments of various sizes in two Indian river basins (Cauvery and Mahanadi). Effect of digital elevation model (DEM) source on estimates of equivalent H-S ratios and characteristics of Geomorphologic Instantaneous Unit Hydrograph (GIUH) derived based on the same are examined by considering SRTM and ASTER DEMs. Results indicate that self-similarity assumptions are valid for the Indian catchments. Comparison of equivalent GIUH derived for each of the catchments based on real channel network with that derived using different DEM sources indicated differences that could be attributed to DEM-based uncertainty associated with estimates of: (i) equivalent H-S ratios that are functions of the self-similarity properties of channel network, and (ii) equivalent length of highest order stream that depends on self-similarity properties and configuration/characteristics of stream network. This uncertainty cannot be ignored in hydrological studies.

  6. Precise Determination of the Baseline Between the TerraSAR-X and TanDEM-X Satellites

    NASA Astrophysics Data System (ADS)

    Koenig, Rolf; Rothacher, Markus; Michalak, Grzegorz; Moon, Yongjin

    TerraSAR-X, launched on June 15, 2007, and TanDEM-X, to be launched in September 2009, both carry the Tracking, Occultation and Ranging (TOR) category A payload instrument package. The TOR consists of a high-precision dual-frequency GPS receiver, called Integrated GPS Occultation Receiver (IGOR), for precise orbit determination and atmospheric sounding and a Laser retro-reflector (LRR) serving as target for the global Satellite Laser Ranging (SLR) ground station network. The TOR is supplied by the GeoForschungsZentrum Potsdam (GFZ) Germany, and the Center for Space Research (CSR), Austin, Texas. The objective of the German/US collaboration is twofold: provision of atmospheric profiles for use in numerical weather predictions and climate studies from the occultation data and precision SAR data processing based on precise orbits and atmospheric products. For the scientific objectives of the TanDEM- X mission, i.e., bi-static SAR together with TerraSAR-X, the dual-frequency GPS receiver is of vital importance for the millimeter level determination of the baseline or distance between the two spacecrafts. The paper discusses the feasibility of generating millimeter baselines by the example of GRACE, where for validation the distance between the two GRACE satellites is directly available from the micrometer-level intersatellite link measurements. The distance of the GRACE satellites is some 200 km, the distance of the TerraSAR-X/TanDEM-X formation will be some 200 meters. Therefore the proposed approach is then subject to a simulation of the foreseen TerraSAR-X/TanDEM-X formation. The effect of varying space environmental conditions, of possible phase center variations, multi path, and of varying center of mass of the spacecrafts are evaluated and discussed.

  7. Constructing a prior information base for river mapping from digital images and DEMs by an advanced image interpretation system

    NASA Astrophysics Data System (ADS)

    Demirkesen, Ali Can

    The purpose of this dissertation is to describe the construction of a prior information-base (interpretation of river characteristics) for river mapping from digital representations, such as remotely sensed digital images and DEMs, by an advanced image interpretation system. More reliable prior information availability in an advanced image interpretation system enables GIS and remote sensing facilities to locate rivers in an easier, more accurate and more straightforward way. In this study, the author proposes a prior information-base including some rules and facts for river mapping from the use of both remotely sensed multi-spectral images and DEMs. These rules not only allow water-related applications in both GIS and remote sensing to be more accurate, but also construct the information-base for river mapping by an advanced image interpretation system. These rules were constructed as a synthesis from searching the literature and experiments with both digital images and DEMs. These rules are employed in an advanced image interpretation system which requires (1) a prior information-base; (2) a working memory; (3) an inference module (Caelli and Bischof, 1997; Schenk and Zilberstein, 1990). A prior information-base is formed by a set of rules (qualitative or quantitative or relationships). A working memory has the basic function of holding features in the form of spatial data and their attribute values. These spatial and attribute data are used by interpreters to activate the rules. Inference module refers to software and hardware that connect the user's questions to the prior information-base and instruct the user (interpreter) about the process. In this dissertation, a prior information-based river mapping was implemented and the proposed rules were tested studying both images and DEMs in IDRISI, as well as RiverTools.

  8. Direct micromechanics derivation and DEM confirmation of the elastic moduli of isotropic particulate materials: Part I No particle rotation

    NASA Astrophysics Data System (ADS)

    Fleischmann, J. A.; Drugan, W. J.; Plesha, M. E.

    2013-07-01

    We derive the macroscopic elastic moduli of a statistically isotropic particulate aggregate material via the homogenization methods of Voigt (1928) (kinematic hypothesis), Reuss (1929) (static hypothesis), and Hershey (1954) and Kröner (1958) (self-consistent hypothesis), originally developed to treat crystalline materials, from the directionally averaged elastic moduli of three regular cubic packings of uniform spheres. We determine analytical expressions for these macroscopic elastic moduli in terms of the (linearized) elastic inter-particle contact stiffnesses on the microscale under the three homogenization assumptions for the three cubic packings (simple, body-centered, and face-centered), assuming no particle rotation. To test these results and those in the literature, we perform numerical simulations using the discrete element method (DEM) to measure the overall elastic moduli of large samples of randomly packed uniform spheres with constant normal and tangential contact stiffnesses (linear spring model). The beauty of DEM is that simulations can be run with particle rotation either prohibited or unrestrained. In this first part of our two-part series of papers, we perform DEM simulations with particle rotation prohibited, and we compare these results with our theoretical results that assumed no particle rotation. We show that the self-consistent homogenization assumption applied to the locally body-centered cubic (BCC) packing most accurately predicts the measured values of the overall elastic moduli obtained from the DEM simulations, in particular Poisson's ratio. Our new analytical self-consistent results lead to significantly better predictions of Poisson's ratio than all prior published theoretical results. Moreover, our results are based on a direct micromechanics analysis of specific geometrical packings of uniform spheres, in contrast to all prior theoretical analyses, which were based on difficult-to-verify hypotheses involving overall inter

  9. Kernschmelze Der nachhaltige Einfluss von Nuklearwaffen auf Politik und Wirtschaft

    NASA Astrophysics Data System (ADS)

    Greiner, Bernd

    "Was sollen wir von einer Kultur halten, der die Ethik stets als wesentliches Element des menschlichen Lebens galt, die aber - außer in fachlicher oder spieltheoretischer Terminologie - nicht in der Lage war, über die Möglichkeit zu sprechen, nahezu alle Menschen zu töten?" Der Fragesteller gehört zu den berühmtesten Physikern des 20. Jahrhunderts und zu den nach wie vor Umstrittensten. über ihn wurde in den 1960er Jahren ein international viel beachtetes Theaterstück geschrieben, vor wenigen Jahren gar eine Oper.

  10. Development of New Accurate, High Resolution DEMs and Merged Topographic-Bathymetric Grids for Inundation Mapping in Seward Alaska

    NASA Astrophysics Data System (ADS)

    Marriott, D.; Suleimani, E.; Hansen, R.

    2004-05-01

    The Geophysical Institute of the University of Alaska Fairbanks and the Alaska Division of Geological and Geophysical Surveys continue to participate in the National Tsunami Hazard Mitigation Program by evaluating and mapping potential inundation of selected coastal communities in Alaska. Seward, the next Alaskan community to be mapped, has excellent bathymetric data but very poor topographic data available. Since one of the most significant sources of errors in tsunami inundation mapping is inaccuracy of topographic and bathymetric data, the Alaska Tsunami Modeling Team cooperated with the local USGS glaciology office to perform photogrammetry in the Seward area to produce a new DEM. Using ten air photos and the APEX photogrammetry and analysis software, along with several precisely located GPS points, we developed a new georeferenced and highly accurate DEM with a 5-meter grid spacing. A variety of techniques were used to remove the effects of buildings and trees to yield a bald earth model. Finally, we resampled the new DEM to match the finest resolution model grid, and combined it with all other data, using the most recent and accurate data in each region. The new dataset has contours that deviate by more than 100 meters in some places from the contours in the previous dataset, showing significant improvement in accuracy for the purpose of tsunami modeling.

  11. Observations of glacier mass changes and their system inherent drivers over Western Himalaya (Himachal Pradesh, India) during 2000-2013 using TanDEM-X and SRTM-C DEMs

    NASA Astrophysics Data System (ADS)

    Vijay, Saurabh; Braun, Matthias

    2016-04-01

    The glaciers in Himachal Pradesh (HP), India (Western Himalaya) are a part of widely spread Hindu Kush-Karakoram-Himalaya mountain ranges. The glacier mass changes depend on system inherent (size, topography, aspect etc.) and climatic factors (precipitation, temperature etc.). The glaciers in this region are mostly debris-covered with supraglacial ponds. They are mostly land-terminating but few of them terminate at the lakes. The two different precipitation regimes namely, Indian summer monsoon and mid-latitude winter westerlies, influence the glaciers in the region. The continuous observations of such glacier changes using field experiments are often limited and repeat pass satellite data potentially fills this gap. Previous studies notified that the bench mark glacier, called Chhota Shigri Glacier, experienced a transition from mass gain (or equilibrium) to loss around 1999. This study aims to estimate the mass change of glaciers in HP at two different time scales. During 2000-2012, we subtract TanDEM-X DEMs of Feb, 2012 from the SRTM C/X band DEM of Feb, 2000. The published ice thickness change of Chhota Shigri Glacier from field observations is compared with ice thickness change derived from DEM differencing. This potentially estimates the bias in thickness change due to different radar frequencies (C band for SRTM, X band for TanDEM-X). For 2012-2013, we use repeat pass TanDEM-X DEMs which don't require any further bias correction. We perform hypsometry analysis (25 m elevation bin) of thickness change of ~800 km2 of ice covered area during these times scales. The analysis shows a transition of thickness change -2.0 myr-1 (4000-4200 m elevation) to -2.7 myr-1 at higher elevations (4200-4800) and further transits upstream. This clearly shows that the presence of thick debris at the glacier tongue act as insulator and reduce the downwasting. The downwasting increases as the surface consists of thin debris and exposed more to radiation. The downwasting linearly

  12. Volcanic geomorphology of Tambora (Sumbawa island, Indonesia) on the basis of SRTM DEM data

    NASA Astrophysics Data System (ADS)

    Favalli, Massimiliano; Karátson, David; Gertisser, Ralf; Fornaciai, Alessandro

    2016-04-01

    Tambora volcano (ca. 2700 m a.s.l.), famous for its great 1815 eruption, is located at the western tip of Sanggar Peninsula, Sumbawa. It is characterized by trachybasalts, trachyandesites and tephriphonolites that build up a 30 x 40 km and >1000 km3 large shield-like volcano (Self et al. 1984), inferred to be up to 4,300 m high prior to 1815. The volcano was truncated during the 1815 eruption by a 6 x 7 km wide, 1.2 km deep caldera, revealing pre-eruptive units in the caldera walls (e.g. 1-5 ka tuff layers and <43 ka lava series) and minor features of post-1815 activity on the caldera floor. In our study we use 30 m-resolution SRTM DEM data to constrain the pre-1815 volcanic geomorphology of the volcano. Representative sections along the volcano flanks show that 1) the volcano shape can be best constrained by exponential and not linear profiles, pointing to an original composite- rather than a shield-like volcano, and 2) the edifice is somewhat elongated in NNW-SSE direction, thus having an elliptical and not circular shape. With these findings, we attempted to construct the palaeo-topography of the volcano by fitting a regular surface onto the existent one using the method of Favalli et al. (2014). Our results show that, when fitting the surface to all topography data of the flanks, the reconstructed summit has an elevation of <3,500 m a.s.l., whereas fitting a regular surface from above (i.e. by enhancing topographic outliers), the original volcano summit has an elevation of ~3,900 m. When assessing the altitude, we need to take into account that prior to 1815 the volcano may not have been a simple cone, but a rather more complex edifice with two peaks and/or perhaps a small caldera, so we prefer an original elevation ~3,700 m. This still makes Tambora one of the highest volcanoes along the Sunda arc, comparable to Semeru or Rinjani. Interpretation of the SRTM DEM surface also allows other volcano-geomorphic features to be inferred. The relatively undissected

  13. Looking Through the Ice: Searching for Past and Present Habitable Zones in the Martian North Polar Region Using MOLA DEMs

    NASA Astrophysics Data System (ADS)

    Payne, M. C.; Farmer, J. D.

    2002-12-01

    Hydrothermal systems have been acknowledged as important gateways to accessing a potential subsurface biology (extant or extinct) on Mars. Groundwater circulation, sustained for up to one billion years by large plutonic bodies (as modeled by previous authors), might well be capable of tapping into a deep subsurface biosphere and subsequently carrying members of microbial communities to the surface. Hence, future robotic missions with near surface drilling capabilities may be able to unearth cryopreserved biosignatures, or perhaps extant organisms, in the midst of the hydrothermal system itself. Digital Elevation Models (DEMs) constructed from Mars Orbiter Laser Altimeter (MOLA) data have proved to be a valuable tool in the search for potential habitable zones for extant and extinct life, and the detection of possible hydrothermal systems on Mars. When formatted for use in a Geographical Information Systems (GIS) software package such as ESRI's ArcView, MOLA data can be used to compose DEMs. Those DEMs can, in turn, be used to create contour maps, to allow profiling through features of interest, and to generate hillshaded views, which provide an image-like perspective of a selected area. Furthermore, DEMs eliminate many problems associated with photographic images such as over-/underexposure, poor focus, and albedo values too high or low for optimal observations. During this study, DEMs were used in the analysis of several regions north of 70° N latitude, in the Martian north polar cap and polar cap margin. The regions were selected during a Viking image survey that concentrated on the location of surface expressions of potential magma-ice interactions, and hence past or present hydrothermal activity. Specific features sought included individual volcanoes and volcanic fields, as well as pseudocrater fields, subglacial volcanic constructs (such as tuyas and tindar ridges), fluvial channels and outwash plains (indicative of j”kulhlaup flooding events), possible

  14. Analysis of Influence of Terrain Relief Roughness on dem Accuracy Generated from LIDAR in the Czech Republic Territory

    NASA Astrophysics Data System (ADS)

    Hubacek, M.; Kovarik, V.; Kratochvil, V.

    2016-06-01

    Digital elevation models are today a common part of geographic information systems and derived applications. The way of their creation is varied. It depends on the extent of area, required accuracy, delivery time, financial resources and technologies available. The first model covering the whole territory of the Czech Republic was created already in the early 1980's. Currently, the 5th DEM generation is being finished. Data collection for this model was realized using the airborne laser scanning which allowed creating the DEM of a new generation having the precision up to a decimetre. Model of such a precision expands the possibilities of employing the DEM and it also offers new opportunities for the use of elevation data especially in a domain of modelling the phenomena dependent on highly accurate data. The examples are precise modelling of hydrological phenomena, studying micro-relief objects, modelling the vehicle movement, detecting and describing historical changes of a landscape, designing constructions etc. Due to a nature of the technology used for collecting data and generating DEM, it is assumed that the resulting model achieves lower accuracy in areas covered by vegetation and in built-up areas. Therefore the verification of model accuracy was carried out in five selected areas in Moravia. The network of check points was established using a total station in each area. To determine the reference heights of check points, the known geodetic points whose heights were defined using levelling were used. Up to several thousands of points were surveyed in each area. Individual points were selected according to a different configuration of relief, different surface types, and different vegetation coverage. The sets of deviations were obtained by comparing the DEM 5G heights with reference heights which was followed by verification of tested elevation model. Results of the analysis showed that the model reaches generally higher precision than the declared one in

  15. Application of Bistatic TanDEM-X Interferometry to Measure Lava Flow Volume and Lava Extrusion Rates During the 2012-13 Tolbachik, Kamchatka Fissure Eruption

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2015-12-01

    Aerial imaging methods are a well approved source for mapping lava flows during eruptions and can serve as a base to assess the eruption dynamics and to determine the affected area. However, clouds and smoke often hinder optical systems like the Earth Observation Advanced Land Imager (EO-1-ALI, operated by NASA) to map lava flows properly, which hence affects its reliability. Furthermore, the amount of lava that is extruded during an eruption cannot be determined from optical images - however, it can significantly contribute to assess the accompanying hazard and risk. One way to monitor active lava flows is to quantify the topographic changes over time while using up-to-date high-resolution digital elevation models (DEMs). Whereas photogrammetric methods still fail when clouds and fume obstruct the sight, innovative radar satellite missions have the potential to generate high-resolution DEMs at any time. The innovative bistatic TanDEM-X (TerraSAR-X Add-on for Digital Elevation Measurements) satellite mission enables for the first time generating high-resolution DEMs from synthetic aperture radar satellite data repeatedly with reasonable costs and high resolution. The satellite mission consists of the two nearly identical satellites TerraSAR-X and TanDEM-X that build a large synthetic aperture radar interferometer with adaptable across- and along-track baselines aiming to generate topographic information globally. In the present study, we apply the TanDEM-X data to study the lava flows that were emplaced during the 2012-13 Tolbachik, Kamchatka fissure eruption. The eruption was composed of very fluid lava flows that effused along a northeast-southwest trending fissure. We used about fifteen bistatic data pairs to generate DEMs prior to, during, and after the eruption. The differencing of the DEMs enables mapping the lava flow field at different times. This allows measuring the extruded volume and to derive the changes in lava extrusion over time.

  16. Integration of SRTM DEM and Hydraulic Analysis for Flood Response Planning.

    NASA Astrophysics Data System (ADS)

    Pervez, M.; Asante, K. O.; Smith, J. L.; Verdin, J. P.; Rowland, J.

    2006-12-01

    The ability to delineate potential flood inundation areas is one of the most important requirements for flood response planning. Historical hydrologic records and high-resolution topographic data are essential to model flood inundation and to map areas at risk of inundation. For Afghanistan, historical hydrologic data enable the analysis of flood frequency, but the accurate delineation of flood inundation zones is limited by the lack of high- resolution elevation data. This study has developed a method for coupling hydraulic analysis and Geographic Information System (GIS) technology to delineate flood risk maps of the Helmand and Kabul drainage basins in Afghanistan. Land surface elevation data from the Shuttle Radar Topography Mission (SRTM) were used to create an area-elevation profile with respect to the rivers that flow into these two basins. Using the profile, we computed cross-sectional area and wetted perimeter for each 1-m increment in elevation. Manning's equation was applied to compute river discharge for each 1-m increment in water level using cross-sectional area, wetted perimeter and slope of the respective river reach. Results for the gauged river reaches were compared with 25, 50, and 100-year return period floods based on a flood frequency from the historical stream flow data, and associated depths of water were estimated for each return period flood. Peak flows at gauge stations were extrapolated to ungauged river reaches based on upstream drainage area. The estimated depths of water for each river reach were used as thresholds to identify areas subject to flood inundation, using the SRTM Digital Elevation Model (DEM) with respect to the rivers. The resulting flood inundation polygons were combined in a GIS with roads, infrastructure, settlements, and higher resolution satellite imagery to identify potential hazards due to flooding, and provide detailed information for flood response planning.

  17. Integrated use of satellite images, DEMs, soil and substrate data in studying mountainous lands

    NASA Astrophysics Data System (ADS)

    Giannetti, Fabio; Montanarella, Luca; Salandin, Roberto

    A method based on the integration into a GIS of satellite images of different spatial resolution (Landsat TM and SPOT), Digital Elevation Models, geo-lithological maps and some soil-landscape data was developed and applied to a test area on a sector of the Italian northwestern Alps in the Piemonte region (Pellice, Po, Varaita and Maira valleys southwest of Torino). The main working steps performed (using GIS software) in this area were: (1) acquisition of geo-lithological and geomorphological maps available and a first definition of homogeneous zones obtained by joining different classes with pedogenic criteria; (2) processing and classification of satellite images to define homogeneous areas with reference to prevailing land cover, land use pattern, relief shape and spectral characters; (3) integration of the previous two layers to obtain a first set of cartographic units showing a distinctive and often repetitive pattern of land form, land cover and parent material; and (4) processing DEMs (slope and aspect), soil or soil-landscape data in order to refine data and characterise the units. The resulting cartographic units were superimposed on a soil-landscape map realised by means of stereoscopic interpretation of aerial photographs by IPLA at the same scale (1:250,000). This comparison was used to verify the correctness of the satellite image processing steps and consistency with the map scale used. A larger scale application was also developed for grassland at 1:50,000 scale to demonstrate the practical use of remote sensing and GIS data in assisting mountainous land development.

  18. Global DEM Errors Underpredict Coastal Vulnerability to Sea Level Rise and Flooding

    NASA Astrophysics Data System (ADS)

    Kulp, Scott; Strauss, Benjamin

    2016-04-01

    Elevation data based on NASA's Shuttle Radar Topography Mission (SRTM) have been widely used to evaluate threats from global sea level rise, storm surge, and coastal floods. However, SRTM data are known to include large vertical errors in densely urban or densely vegetated areas. The errors may propagate to derived land and population exposure assessments. We compare assessments based on SRTM data against references employing high-accuracy bare-earth elevation data generated from lidar data available for coastal areas of the United States. We find that both 1-arcsecond and 3-arcsecond horizontal resolution SRTM data systemically underestimate exposure across all assessed spatial scales and up to at least 10m above the high tide line. At 3m, 1-arcsecond SRTM underestimates U.S. population exposure by more than 60%, and under-predicts population exposure in 90% of coastal states, 87% of counties, and 83% of municipalities. These fractions increase with elevation, but error medians and variability fall to lower levels, with national exposure underestimated by just 24% at 10m. Results using 3-arcsecond SRTM are extremely similar. Coastal analyses based on SRTM data thus appear to greatly underestimate sea level and flood threats, especially at lower elevations. However, SRTM-based estimates may usefully be regarded as providing lower bounds to actual threats. We additionally assess the performance of NOAA's Global Land One-km Base Elevation Project (GLOBE), another publicly-available global DEM, but do not reach any definitive conclusion because of the spatial heterogeneity in its quality.

  19. Formation of fluvial knickzones in Japanese mountainous areas: A spatial analysis using GIS and DEMs

    NASA Astrophysics Data System (ADS)

    Hayakawa, Y. S.; Oguchi, T.

    2006-12-01

    Fluvial knickzones are the elements of bedrock rivers that can enhance stream erosion into bedrock, and they can be key morphologies highlighting interactions among earth surface processes such as erosion, tectonics, and volcanism. This study examines the longitudinal profiles of Japanese mountain rivers to illustrate the distribution of knickzones and discusses their role in the landscape development. Using 50-m DEMs, knickzones were extracted based on a quantitative criterion, and 5,753 knickzones were identified in the rivers of ca. 65,000 km long. The location of the knickzones was then examined along with other GIS data including topography, geology and precipitation. Overall, topographical conditions have the strongest influences on knickzone abundance, and upstream steep reaches of the rivers are more favorable for knickzone existence. The knickzone abundance for each rock type is also controlled by stream gradients, and lighologic boundaries do not show significant correlations with the knickzone locations. The controls of lithologic substrate on the knickzone locations are therefore limited. The abundant knickzones in steep river reaches indicate a hydraulic origin of knickzones, where stream erosions have enough strength in shaping the bedrock. Moreover, the knickzones are frequently observed in reaches slightly upstream from the major confluences at which stream discharge abruptly increases, indicating that the hydraulic anomalies of water flows at the confluences can cause knickzones which may later migrate upstream. The other possible causes of knickzone initiation including volcanic, tectonic and climatic effects are also suggested. The abundant knickzones in Japanese mountain rivers, resulted from the interactions among surface processes, suggest that river morphology modeling needs to consider the initiation and development of knickzones. tokyo.ac.jp/~hayakawa/

  20. Isotope separation by photodissociation of Van der Waal's molecules

    DOEpatents

    Lee, Yuan T.

    1977-01-01

    A method of separating isotopes based on the dissociation of a Van der Waal's complex. A beam of molecules of a Van der Waal's complex containing, as one partner of the complex, a molecular species in which an element is present in a plurality of isotopes is subjected to radiation from a source tuned to a frequency which will selectively excite vibrational motion by a vibrational transition or through electronic transition of those complexed molecules of the molecular species which contain a desired isotope. Since the Van der Waal's binding energy is much smaller than the excitational energy of vibrational motion, the thus excited Van der Waal's complex dissociate into molecular components enriched in the desired isotope. The recoil velocity associated with vibrational to translational and rotational relaxation will send the separated molecules away from the beam whereupon the product enriched in the desired isotope can be separated from the constituents of the beam.

  1. Quantifizierung neurodegenerativer Veränderungen bei der Alzheimer Krankheit

    NASA Astrophysics Data System (ADS)

    Fritzsche, Klaus H.; Giesel, Frederik L.; Thomann, Philipp A.; Hahn, Horst K.; Essig, Marco; Meinzer, Hans-Peter

    Die objektive Bewertung neurodegenerativer Prozesse stellt für die Diagnose und Therapiebegutachtung neuropsychiatrischer Krankheiten eine wichtige Grundlage dar. Computerbasierte radiodiagnostische Verfahren können pathologische Veränderungen in verschiedenen Hirnarealen quantifizieren und hierbei die rein visuelle Beurteilung der Bilddaten ergänzen. Inhalt dieser Studie ist die Evaluation einer voll automatischen Methode zur voxelbasierten Messung atrophischer Veränderungen im Gehirn, wie sie bei der Alzheimer-Demenz (AD) oder der leichten kognitiven Störung (LKS) auftreten. Es wurde eine signifikante Korrelation mit den semiautomatisch extrahierten Volumina der Temporalhörner festgestellt. Die Präzision, Benutzerfreundlichkeit, Beobachterunabh ängigkeit sowie die kurze Rechenzeit des automatischen Verfahrens sind wichtige Voraussetzungen für den routinemäßigen klinischen Einsatz.

  2. The influence of accuracy, grid size, and interpolation method on the hydrological analysis of LiDAR derived dems: Seneca Nation of Indians, Irving NY

    NASA Astrophysics Data System (ADS)

    Clarkson, Brian W.

    Light Detection and Ranging (LiDAR) derived Digital Elevation Models (DEMs) provide accurate, high resolution digital surfaces for precise topographic analysis. The following study investigates the accuracy of LiDAR derived DEMs by calculating the Root Mean Square Error (RMSE) of multiple interpolation methods with grid cells ranging from 0.5 to 10-meters. A raster cell with smaller dimensions will drastically increase the amount of detail represented in the DEM by increasing the number of elevation values across the study area. Increased horizontal resolutions have raised the accuracy of the interpolated surfaces and the contours generated from the digitized landscapes. As the raster grid cells decrease in size, the level of detail of hydrological processes will significantly improve compared to coarser resolutions including the publicly available National Elevation Datasets (NEDs). Utilizing a LiDAR derived DEM with the lowest RMSE as the 'ground truth', watershed boundaries were delineated for a sub-basin of the Clear Creek Watershed within the territory of the Seneca Nation of Indians located in Southern Erie County, NY. An investigation of the watershed area and boundary location revealed considerable differences comparing the results of applying different interpretation methods on DEM datasets of different horizontal resolutions. Stream networks coupled with watersheds were used to calculate peak flow values for the 10-meter NEDs and LiDAR derived DEMs.

  3. Demographische Entwicklung in der Metropolregion Berlin-Brandenburg

    NASA Astrophysics Data System (ADS)

    Beyer, Wolf; Bluth, Friedrich

    〝Denn eins ist sicher: Die Rente.`` Der vielzitierte Satz des früheren Arbeits- und Sozialministers Norbert Blüm klingt heute vielen wie Hohn. Der Altersaufbau der deutschen Bevölkerung erinnert grafisch immer mehr an einen Baum auf dünnem Stämmchen als an eine Pyramide. Angesichts dessen rücken demographische Entwicklungen mehr und mehr in den Fokus der Öffentlichkeit. Besonders die neuen Bundesländer sind massiv von Abwanderung und einem nie dagewesenen Geburtenrückgang betroffen.DIPL.-GEOGR. UTE C. BAUERsprach mitFRIEDRICH BLUTHundWOLF BEYERüber die Besonderheiten der demographischen Prozesse in Berlin und Brandenburg. Beyer leitete bis Anfang 2004 das brandenburgische Referat für Raumbeobachtung. Seine Aufgabe bestand darin, Planungsgrundlagen für die Gemeinsame Landesplanung Berlin-Brandenburg(GL) zu schaffen. Dazu zählen auch Bevölkerungsprognosen für die Kreise und Städte Brandenburgs. Bluth ist in der Senatsverwaltung für Stadtentwicklung Berlin beschäftigt und leitet dort die Gruppe 〝Stadtwissen, Stadtentwicklungsmonitoring, Bevölkerungsprognose.``

  4. Ripplocations in van der Waals layers.

    PubMed

    Kushima, Akihiro; Qian, Xiaofeng; Zhao, Peng; Zhang, Sulin; Li, Ju

    2015-02-11

    Dislocations are topological line defects in three-dimensional crystals. Same-sign dislocations repel according to Frank's rule |b1 + b2|(2) > |b1|(2) + |b2|(2). This rule is broken for dislocations in van der Waals (vdW) layers, which possess crystallographic Burgers vector as ordinary dislocations but feature "surface ripples" due to the ease of bending and weak vdW adhesion of the atomic layers. We term these line defects "ripplocations" in accordance to their dual "surface ripple" and "crystallographic dislocation" characters. Unlike conventional ripples on noncrystalline (vacuum, amorphous, or fluid) substrates, ripplocations tend to be very straight, narrow, and crystallographically oriented. The self-energy of surface ripplocations scales sublinearly with |b|, indicating that same-sign ripplocations attract and tend to merge, opposite to conventional dislocations. Using in situ transmission electron microscopy, we directly observed ripplocation generation and motion when few-layer MoS2 films were lithiated or mechanically processed. Being a new subclass of elementary defects, ripplocations are expected to be important in the processing and defect engineering of vdW layers.

  5. Supercurrent in van der Waals Josephson junction.

    PubMed

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency.

  6. Dielectric Genome of van der Waals Heterostructures.

    PubMed

    Andersen, Kirsten; Latini, Simone; Thygesen, Kristian S

    2015-07-01

    Vertical stacking of two-dimensional (2D) crystals, such as graphene and hexagonal boron nitride, has recently lead to a new class of materials known as van der Waals heterostructures (vdWHs) with unique and highly tunable electronic properties. Ab initio calculations should in principle provide a powerful tool for modeling and guiding the design of vdWHs, but in their traditional form such calculations are only feasible for commensurable structures with a few layers. Here we show that the dielectric properties of realistic, incommensurable vdWHs comprising hundreds of layers can be efficiently calculated using a multiscale approach where the dielectric functions of the individual layers (the dielectric building blocks) are computed ab initio and coupled together via the long-range Coulomb interaction. We use the method to illustrate the 2D-3D transition of the dielectric function of multilayer MoS2 crystals, the hybridization of quantum plasmons in thick graphene/hBN heterostructures, and to demonstrate the intricate effect of substrate screening on the non-Rydberg exciton series in supported WS2. The dielectric building blocks for a variety of 2D crystals are available in an open database together with the software for solving the coupled electrodynamic equations.

  7. Supercurrent in van der Waals Josephson junction

    PubMed Central

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency. PMID:26830754

  8. Van der Waals Interactions Involving Proteins

    NASA Technical Reports Server (NTRS)

    Roth, Charles M.; Neal, Brian L.; Lenhoff, Abraham M.

    1996-01-01

    Van der Waals (dispersion) forces contribute to interactions of proteins with other molecules or with surfaces, but because of the structural complexity of protein molecules, the magnitude of these effects is usually estimated based on idealized models of the molecular geometry, e.g., spheres or spheroids. The calculations reported here seek to account for both the geometric irregularity of protein molecules and the material properties of the interacting media. Whereas the latter are found to fall in the generally accepted range, the molecular shape is shown to cause the magnitudes of the interactions to differ significantly from those calculated using idealized models. with important consequences. First, the roughness of the molecular surface leads to much lower average interaction energies for both protein-protein and protein-surface cases relative to calculations in which the protein molecule is approximated as a sphere. These results indicate that a form of steric stabilization may be an important effect in protein solutions. Underlying this behavior is appreciable orientational dependence, one reflection of which is that molecules of complementary shape are found to exhibit very strong attractive dispersion interactions. Although this has been widely discussed previously in the context of molecular recognition processes, the broader implications of these phenomena may also be important at larger molecular separations, e.g., in the dynamics of aggregation, precipitation, and crystal growth.

  9. Modern theory of van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Dobson, John

    2014-03-01

    van der Waals (vdW, dispersion) interactions are important in diverse areas such as colloid, surface and nano science, cohesion of molecular crystals, and biomolecular science. They also provide competition in experiments to discover the fifth fundamental force.While vdW interactions have been understood in principle for a century, their quantitative first-principles prediction and modelling down to chemical contact separations have proven stubbornly difficult because the quantal many-electron problem is involved. After some brief historical material, the current state of the art will be discussed with particular reference to several approaches: pairwise additive, perturbative quantum chemical, vdW-DF, Lifshitz-like scattering, RPA-like, Adiabatic Connection Fluctuation Dissipation / Time Dependent DFT based etc.. A potentially useful classification will be introduced to aid in understanding the physical causes of departures from pairwise additivity, that is from the usual sum of C6R-6 contributions. These departures result in non-standard power law decays of nanostructure vdW interactions as a function of separation D, as well as surprising dependences of the attraction on the number, N, of atoms within each vdW-interacting fragment. Some further recent results on non-additivity will also be presented. Work supported by an Australian Research Council Discovery Grant.

  10. Van der Waals Interactions in Aspirin

    NASA Astrophysics Data System (ADS)

    Reilly, Anthony; Tkatchenko, Alexandre

    2015-03-01

    The ability of molecules to yield multiple solid forms, or polymorphs, has significance for diverse applications ranging from drug design and food chemistry to nonlinear optics and hydrogen storage. In particular, aspirin has been used and studied for over a century, but has only recently been shown to have an additional polymorphic form, known as form II. Since the two observed solid forms of aspirin are degenerate in terms of lattice energy, kinetic effects have been suggested to determine the metastability of the less abundant form II. Here, first-principles calculations provide an alternative explanation based on free-energy differences at room temperature. The explicit consideration of many-body van der Waals interactions in the free energy demonstrates that the stability of the most abundant form of aspirin is due to a subtle coupling between collective electronic fluctuations and quantized lattice vibrations. In addition, a systematic analysis of the elastic properties of the two forms of aspirin rules out mechanical instability of form II as making it metastable.

  11. Forecasting of Storm-Surge Floods Using ADCIRC and Optimized DEMs

    NASA Technical Reports Server (NTRS)

    Valenti, Elizabeth; Fitzpatrick, Patrick

    2006-01-01

    eight-node Linux computer cluster. Each node contained dual 2-GHz processors, 2GB of memory, and a 40GB hard drive. The digital elevation model (DEM) for this region was specified using a combination of Navy data (over water), NOAA data (for the coastline), and optimized Interferometric Synthetic Aperture Radar data (over land). This high-resolution topographical data of the Mississippi coastal region provided the ADCIRC model with improved input with which to calculate improved storm-surge forecasts.

  12. Forecasting Rainfall Induced Landslide using High Resolution DEM and Simple Water Budget Model

    NASA Astrophysics Data System (ADS)

    Luzon, P. K. D.; Lagmay, A. M. F. A.

    2014-12-01

    Philippines is hit by an average of 20 typhoons per year bringing large amount of rainfall. Monsoon carrying rain coming from the southwest of the country also contributes to the annual total rainfall that causes different hazards. Such is shallow landslide mainly triggered by high saturation of soil due to continuous downpour which could take up from hours to days. Recent event like this happened in Zambales province September of 2013 where torrential rain occurred for 24 hours amounting to half a month of rain. Rainfall intensity measured by the nearest weather station averaged to 21 mm/hr from 10 pm of 22 until 10 am the following day. The monsoon rains was intensified by the presence of Typhoon Usagi positioned north and heading northwest of the country. A number of landslides due to this happened in 3 different municipalities; Subic, San Marcelino and Castillejos. The disaster have taken 30 lives from the province. Monitoring these areas for the entire country is but a big challenge in all aspect of disaster preparedness and management. The approach of this paper is utilizing the available forecast of rainfall amount to monitor highly hazardous area during the rainy seasons and forecasting possible landslide that could happen. A simple water budget model following the equation Perct=Pt-R/Ot-∆STt-AETt (where as the terms are Percolation, Runoff, Change in Storage, and Actual Evapotraspiration) was implemented in quantifying all the water budget component. Computations are in Python scripted grid system utilizing the widely used GIS forms for easy transfer of data and faster calculation. Results of successive runs will let percolation and change in water storage as indicators of possible landslide.. This approach needs three primary sets of data; weather data, topographic data, and soil parameters. This research uses 5 m resolution DEM (IfSAR) to define the topography. Soil parameters are from fieldworks conducted. Weather data are from the Philippine

  13. Coupled LBM-DEM Three-phase Simulation on Gas Flux Seeping from Marine Sediment

    NASA Astrophysics Data System (ADS)

    Kano, Y.; Sato, T.

    2014-12-01

    One of the main issues of the geological storage of CO2 under the seabed is a risk of CO2 leakage. Once CO2seeps into the ocean, it rises in water column dissolving into seawater, which results in the acidification of seawater and/or returning to the air. Its behaviour significantly depends on flow rate and bubble size (Kano et al., 2009; Dewar et al., 2013). As for porous media, bubble size is generally predicted through simple force balance based on flow rate, surface tension and channel size which is estimated by porosity and grain size. However, in shallow marine sediments, grains could be mobilised and displaced by buoyant gas flow, which causes distinctive phenomena such as blow-out or formation of gas flow conduit. As a result, effective gas flux into seawater can be intermissive, and/or concentrated in narrow area (QICS, 2012; Kawada, 2013). Bubble size is also affected by these phenomena. To predict effective gas flux and bubble size into seawater, three-phase behaviour of gas-water-sediment grains should be revealed. In this presentation, we will report the results of gas-liquid-solid three-phase simulations and their comparisons with experimental and observation data. Size of solid particles is based on grain size composing marine sediments at some CCS project sites. Fluid-particle interactions are solved using the lattice Boltzmann method (LBM), while the particle-particle interactions are treated by coupling with the Discrete Element method (DEM). References: Dewar, M., Wei, W., McNeil, D., Chen, B., 2013. Small-scale modelling of the physiochemical impacts of CO2leaked from sub-seabed reservoirs or pipelines within the North Sea and surrounding waters. Marine Pollution Bulletin 73(2), 504-515. Kano, Y., Sato, T., Kita, J., Hirabayashi, S., Tabeta, S., 2009. Model prediction on the rise of pCO2 in uniform flows by leakage of CO2purposefully stored under the seabed. Int. J. Greenhouse Gas Control, Vol. 3(5), 617-625. Kawada, R. 2014. A study on the

  14. Large Area Mountain Permafrost Simulation at DEM Resolution. Results from the European Alps and Himalaya

    NASA Astrophysics Data System (ADS)

    Fiddes, J.

    2015-12-01

    We present a system that is able to simulate land-surface conditions at continental scales while accounting for parameters that vary on order of 10's of metres (e.g., topography or surface cover) by using a statistical subgrid scheme (Fiddes and Gruber 2012). The model chain is driven by output from atmospheric datasets with a simple in-house downscaling scheme which uses only data on atmospheric pressure-levels and a DEM (Fiddes and Gruber 2014). The scheme has been tested in the case of mountain permafrost in the European Alps (Fiddes and Gruber 2015) with good results. However the strength of the scheme is application to remote data-sparse regions. Recently we have applied the scheme to simulate permafrost conditions in the Western Himalaya. This included a simple approach to correct snow mass balance using MODIS products, as input precipitation from atmospheric models may often have bias. The scheme is flexible in choice of atmospheric model input data, numerical surface model and surface data. In this abstract we will (1) present the model chain, (2) show the results of simulating permafrost conditions over large areas using only global datasets as input and (3) give an outlook to simulating future conditions. Fiddes, J., Endrizzi, S., and Gruber, S. 2015: Large-area land surface simulations in heterogeneous terrain driven by global data sets: application to mountain permafrost, The Cryosphere, 9, 411-426, doi:10.5194/tc-9-411-2015, 2015. http://dx.doi.org/10.5194/tc-9-411-2015Fiddes, J. & Gruber, S. 2014: TopoSCALE v.1.0: downscaling gridded climate data in complex terrain, Geoscientific Model Development, 7, 387-405, http://dx.doi.org/10.5194/gmd-7-387-2014Fiddes, J. & Gruber, S. 2012: TopoSUB: a tool for efficient large area numerical modelling in complex topography at sub-grid scales, Geoscientific Model Development, 5, 1245-1257,http://dx.doi.org/10.5194/gmd-5-1245-2012

  15. Diffusive modeling of global river and floodplain dynamics based on 1km-resolution DEM

    NASA Astrophysics Data System (ADS)

    Yamazaki, D.; Kanae, S.; Oki, T.

    2009-12-01

    Terrestrial water circulation is important both as a component of the climate system and as a freshwater supplying system for human beings. Recent advances in remote sensing have achieved global-scale observation of surface water storage and movement from satellites (e.g. inundated area extent by microwave imagers, terrestrial water storage by GRACE, water surface altitude and river discharge possibly by SWOT). On the other hand, global river routing models, which are practically the only available tool for simulating terrestrial water circulation, have not adequately represented the physical mechanism of terrestrial water storage and movement, such as floodplain inundation dynamics regulated by much smaller-scale topography than global model resolution. A newly developed global river routing model named “Catchment-based Macro-scale Floodplain model” (CaMa-Flood) overcomes this drawback by detailed representation of sub-grid-scale topography (ex. river channel cross-section, catchment boundaries, and floodplain elevation profile). These sub-grid features regulating surface water dynamics are objectively parameterized based on 1km-resolution global DEM and flow direction map. This approach enables explicit prediction of surface water altitude, which is essential for diffusive wave modeling of floodplain inundation dynamics. Thus, CaMa-Flood is expected to simulate not only realistic river discharge but also water depth, inundated area extent, and surface water storage. Improvements from previous global river routing models achieved by CaMa-Flood are summarized as follows: (1) objective parameterization of sub-grid topographies using 1km-resolution datasets, (2) explicit representation of floodplain inundation dynamics, (3) diffusive wave modeling for flow computation instead of kinematic wave modeling, and (4) two dimensional expression of inundated area extent which can be validated against satellite observations. Ability of CaMa-Flood is tested by comparing

  16. Stufenweise Integration von eLearning an der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Pätzold, Sebastian; Graf, Stephan; Gergintchev, Ivan; Pongratz, Hans; Rathmayer, Sabine

    Der vorliegende Beitrag beschreibt als Best Practice Beispiel die stufenweise Integration eines Learning Management Systems (LMS) in die Infrastruktur von Information und Kommunikation (IuK) der Technischen Universität München (TUM). Dabei wird sowohl die Konsolidierung mehrfach angebotener Funktionalitäten und Dienste in den verschiedenen Portalen der Universität als auch die sukzessive Optimierung der Abläufe aufgezeigt. Gleichzeitig wird auf zukünftige weitere Entwicklungen hin zu einer vollständigen Integration der IuK, aber auch auf die Probleme in den unterschiedlichen Stadien der Entwicklung eingegangen.

  17. Dem Assessment Derived from Close Range Photogrammetry: a Case Study from Kadavur Area, Karur District, Tamil Nadu, India

    NASA Astrophysics Data System (ADS)

    Anbarasan, S.; Sakthivel, R.

    2012-07-01

    Close-Range Photogrammetry is an accurate, cost effective technique of collecting measurements of real world objects and conditions, directly from photographs. Photogrammetry utilizes digital images to obtain accurate measurements and geometric data of the object or area of interest, in order to provide spatial information for Engineering design, spatial surveys or 3D modeling. The benefits of close-range Photogrammetry over other field procedures are purported to be: Increased accuracy; complete as-built information; reduced costs; reduced on-site time; and effective for small and large projects. The same basic principle of traditional Aerial Photogrammetry can be applied to stereoscopic pictures taken from lower altitudes or from the ground. Terrestrial, ground-based, and close-range are all descriptive terms that refer to photos taken with an object-to-camera distance less than 300m (1000 feet). (Matthews, N.A, 2008). Close range Photogrammetry is a technique for obtaining the geometric information (e.g. position, distance, size and shape) of any object in 3D space that was imaged on the two dimensional (2D) photos, (Wolf, P.R, et.al, 2000) DEM Generation requires many processing and computation, such as camera calibration, stereo matching, editing, and interpolation. All the mentioned steps contribute to the quality of DEM. Image on close range Photogrammetry can be captured using three kind of camera: metric camera, semi-metric camera, and non-metric camera (Hanke, K., et.al, 2002). In this paper DEM quality assessed at Kadavur area, Karur district, Tamil Naudu, India using Close Range Photogrammetry technique, Commercial Digital Camera and Leica Photogrammetry Suite.

  18. Advanced Communication and Control Solutions of Distributed Energy Resources (DER)

    SciTech Connect

    Asgeirsson, Haukur; Seguin, Richard; Sherding, Cameron; de Bruet, Andre, G.; Broadwater, Robert; Dilek, Murat

    2007-01-10

    This report covers work performed in Phase II of a two phase project whose objective was to demonstrate the aggregation of multiple Distributed Energy Resources (DERs) and to offer them into the energy market. The Phase I work (DE-FC36-03CH11161) created an integrated, but distributed, system and procedures to monitor and control multiple DERs from numerous manufacturers connected to the electric distribution system. Procedures were created which protect the distribution network and personnel that may be working on the network. Using the web as the communication medium for control and monitoring of the DERs, the integration of information and security was accomplished through the use of industry standard protocols such as secure SSL,VPN and ICCP. The primary objective of Phase II was to develop the procedures for marketing the power of the Phase I aggregated DERs in the energy market, increase the number of DER units, and implement the marketing procedures (interface with ISOs) for the DER generated power. The team partnered with the Midwest Independent System Operator (MISO), the local ISO, to address the energy market and demonstrate the economic dispatch of DERs in response to market signals. The selection of standards-based communication technologies offers the ability of the system to be deployed and integrated with other utilities’ resources. With the use of a data historian technology to facilitate the aggregation, the developed algorithms and procedures can be verified, audited, and modified. The team has demonstrated monitoring and control of multiple DERs as outlined in phase I report including procedures to perform these operations in a secure and safe manner. In Phase II, additional DER units were added. We also expanded on our phase I work to enhance communication security and to develop the market model of having DERs, both customer and utility owned, participate in the energy market. We are proposing a two-part DER energy market model--a utility

  19. Extracting Precise and Affordable Dems Despite of the Clouds. Ajax: the Joining of Radar and Optical Strengths

    NASA Astrophysics Data System (ADS)

    Cunin, 1 L.; Nonin, 2 P.; Janoth, 3 J.; Bernard, 4 M.

    2012-07-01

    On the one hand, onboard SPOT 5, the HRS instrument systematically collects stereopairs around the Globe since 2002. Each stereopair can encompass an area up to 600 km x 120 km within a single pass (i.e. 72 000 km² stereoscopic strips). Covering now more than 120 millions sq.km of the Earth landmasses, SPOT 5 stereoscopic imagery has become one of main satellite data sources for accurate DEM extraction, at least where the cloud coverage leaves a chance to do so ! On the other hand, the TerraSAR-X satellite, launched in June 2007, is able to collect radar data through the clouds in several modes. An approach to extract height information by radargrammetry was developed, and the commercial distribution of Digital Elevation Models based on TerraSAR-X StripMap and SpotLight Modes (resp. 3m and 1m resolution) has started in 2010. To improve the overall height accuracy of the DEM, acquisitions from both orbit directions are utilised, each point on the ground being thus imaged at least 4 times by TerraSAR-X. Since 2002, Spot Image and French National Cartographic Institute (IGN) are building a worldwide database called Elevation30/Reference3D™, which includes a Digital Elevation Model at 1-arc-second resolution (DTED level 2) extracted from HRS stereopairs. To answer the wide demand of precise DEMs over Tropical and Northern areas, frequently covered by clouds, a study was performed to integrate StripMap radargrammetric TerraSAR-X data into the Reference3D process, and two prototype products were issued, over Colombia and Congo areas. During this experiment, efforts have been made to stick to technical steps that could be integrated within a standardized production process, in order to keep offering affordable prices while maintaining a high standard of horizontal and vertical accuracy. The DEMs extracted from TerraSAR-X and HRS proved extremely consistent with each other, showing a mean difference of 0.80m. This allows to propose a unified Elevation30 product to the

  20. The Discrete Equation Method (DEM) for Fully Compressible Two-Phase Flows in Ducts of Spatially Varying Cross-Section

    SciTech Connect

    Ray A. Berry; Richard Saurel; Tamara Grimmett

    2009-07-01

    Typically, multiphase modeling begins with an averaged (or homogenized) system of partial differential equations (traditionally ill-posed) then discretizes this system to form a numerical scheme. Assuming that the ill-posedness problem is avoided by using a well-posed formulation such as the seven-equation model, this presents problems for the numerical approximation of non-conservative terms at discontinuities (interfaces, shocks) as well as unwieldy treatment of fluxes with seven waves. To solve interface problems without conservation errors and to avoid this questionable determination of average variables and the numerical approximation of the non-conservative terms associated with 2 velocity mixture flows we employ a new homogenization method known as the Discrete Equations Method (DEM). Contrary to conventional methods, the averaged equations for the mixture are not used, and this method directly obtains a (well-posed) discrete equation system from the single-phase system to produce a numerical scheme which accurately computes fluxes for arbitrary numbers of phases and solves non-conservative products. The method effectively uses a sequence of single phase Riemann equation solves. Phase interactions are accounted for by Riemann solvers at each interface. Flow topology can change with changing expressions for the fluxes. Non-conservative terms are correctly approximated. Some of the closure relations missing from the traditional approach are automatically obtained. Lastly, we can often times identify the continuous equation system, resulting from taking the continuous limit with weak wave assumptions, of the discrete equations. This can be very useful from a theoretical standpoint. As a first step toward implict integration of the DEM method in multidimensions, in this paper we construct a DEM model for the flow of two compressible phases in 1-D ducts of spatially varying cross-section to test this approach. To relieve time step size restrictions due to

  1. Die Evolution des Universums. Eine Geschichte der Kosmologie.

    NASA Astrophysics Data System (ADS)

    Hiller, H.

    This volume covers in an elementary course a historical overview on cosmology ranging from the ancient aspects up to big bang theory and the concepts of inflationary universe and grand unified theories. Contents: 1. Auf dem Wege zur Wissenschaft. 2. Die neue Kosmologie. 3. Die Struktur des Weltalls. 4. Dramatik im Weltall. 5. Die endliche Welt. 6. Die Evolution des frühen Universums. 7. Die Zukunft. 8. Die neue Teleologie. 9. Das Leben.

  2. [Beweggründe von Krebspatienten für und gegen die Inanspruchnahme der Misteltherapie].

    PubMed

    Gschwendtner, Kathrin M; Holmberg, Christine; Weis, Joachim

    2016-01-01

    Einleitung: Die Misteltherapie ist im deutschsprachigen Raum ein häufig angewandtes komplementärmedizinisches Verfahren (KM) in der Onkologie. Diese Studie hatte das Ziel, die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie zu untersuchen und Themenfeldern zuzuordnen. Patienten und Methoden: Es wurden qualitative leitfadengestützte Interviews mit Krebspatienten geführt. Der Interviewleitfaden fragte nach der Inanspruchnahme von KM, der Motivation zur Inanspruchnahme, Informationsverhalten und -bedürfnissen zu KM sowie nach der Krebserkrankung. Um die Beweggründe für die Inanspruchnahme oder Nichtinanspruchnahme der Misteltherapie zu verstehen, wurden die Interviews inhaltsanalytisch ausgewertet. Ergebnisse: Insgesamt wurden Interviews mit 88 Krebspatienten geführt, davon nutzen 18 (20,5%) die Misteltherapie. Die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie ließen sich den 2 Themenfeldern «Wahrgenommene Indikation» und «Abwägungen bei der Entscheidungsfindung» zuordnen. Diskussion und Schlussfolgerungen: Mit der Misteltherapie wird sowohl ein Einfluss auf das Tumorwachstum als auch eine supportive Wirkung assoziiert. Anwender sehen die Misteltherapie als sicheres Verfahren; Nichtnutzer befürchten eher Neben- oder Wechselwirkungen. Die Empfehlung von Fachpersonal spielt eine wichtige Rolle bei der Inanspruchnahme. Zum Teil waren die Nichtnutzer interessiert an der Anwendung der Misteltherapie, befanden sich jedoch noch im Klärungsprozess.

  3. Structure-based design and screening of inhibitors for an essential bacterial GTPase, Der.

    PubMed

    Hwang, Jihwan; Tseitin, Vladimir; Ramnarayan, Kal; Shenderovich, Mark D; Inouye, Masayori

    2012-05-01

    Der is an essential and widely conserved GTPase that assists assembly of a large ribosomal subunit in bacteria. Der associates specifically with the 50S subunit in a GTP-dependent manner and the cells depleted of Der accumulate the structurally unstable 50S subunit, which dissociates into an aberrant subunit at a lower Mg(2+) concentration. As Der is an essential and ubiquitous protein in bacteria, it may prove to be an ideal cellular target against which new antibiotics can be developed. In the present study, we describe our attempts to identify novel antibiotics specifically targeting Der GTPase. We performed the structure-based design of Der inhibitors using the X-ray crystal structure of Thermotoga maritima Der (TmDer). Virtual screening of commercially available chemical library retrieved 257 small molecules that potentially inhibit Der GTPase activity. These 257 chemicals were tested for their in vitro effects on TmDer GTPase and in vivo antibacterial activities. We identified three structurally diverse compounds, SBI-34462, -34566 and -34612, that are both biologically active against bacterial cells and putative enzymatic inhibitors of Der GTPase homologs. We also presented the possible interactions of each compound with the Der GTP-binding site to understand the mechanism of inhibition. Therefore, our lead compounds inhibiting Der GTPase provide scaffolds for the development of novel antibiotics against antibiotic-resistant pathogenic bacteria. PMID:22377538

  4. [Beweggründe von Krebspatienten für und gegen die Inanspruchnahme der Misteltherapie].

    PubMed

    Gschwendtner, Kathrin M; Holmberg, Christine; Weis, Joachim

    2016-01-01

    Einleitung: Die Misteltherapie ist im deutschsprachigen Raum ein häufig angewandtes komplementärmedizinisches Verfahren (KM) in der Onkologie. Diese Studie hatte das Ziel, die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie zu untersuchen und Themenfeldern zuzuordnen. Patienten und Methoden: Es wurden qualitative leitfadengestützte Interviews mit Krebspatienten geführt. Der Interviewleitfaden fragte nach der Inanspruchnahme von KM, der Motivation zur Inanspruchnahme, Informationsverhalten und -bedürfnissen zu KM sowie nach der Krebserkrankung. Um die Beweggründe für die Inanspruchnahme oder Nichtinanspruchnahme der Misteltherapie zu verstehen, wurden die Interviews inhaltsanalytisch ausgewertet. Ergebnisse: Insgesamt wurden Interviews mit 88 Krebspatienten geführt, davon nutzen 18 (20,5%) die Misteltherapie. Die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie ließen sich den 2 Themenfeldern «Wahrgenommene Indikation» und «Abwägungen bei der Entscheidungsfindung» zuordnen. Diskussion und Schlussfolgerungen: Mit der Misteltherapie wird sowohl ein Einfluss auf das Tumorwachstum als auch eine supportive Wirkung assoziiert. Anwender sehen die Misteltherapie als sicheres Verfahren; Nichtnutzer befürchten eher Neben- oder Wechselwirkungen. Die Empfehlung von Fachpersonal spielt eine wichtige Rolle bei der Inanspruchnahme. Zum Teil waren die Nichtnutzer interessiert an der Anwendung der Misteltherapie, befanden sich jedoch noch im Klärungsprozess. PMID:27606463

  5. [Professor Hans Otto Lüders].

    PubMed

    Tsuji, Sadatoshi

    2014-11-01

    Professor Lüders has made significant contributions to Clinical Neurology and particularly to Epilepsy and Clinical Neurophysiology. Some of his most important contributions include the following: 1.He pioneered the use of chronically implanted, large plates of subdural electrodes in the presurgical evaluation of patient who were candidates for epilepsy surgery. These electrodes were used to record epileptic seizures and by electrical stimulation to establish the location of eloquent cortex. Lately he has also advocated the use in the USA of stereotactically implanted depth electrodes for presurgical evaluation of epilepsy patients who had deep seated epileptic foci which were impossible to assess with subdural electrodes. These techniques were imported from Europe. 2.Mapping studies with subdural electrodes led to the discovery of a number of cortical eloquent areas that had not been described before: a. The basal temporal language area located in the dominant fusiform gyrus. b. The "negative motor areas" located in the caudal region of the inferior frontal gyrus (bilaterally) and immediately in mesial frontal pre-SMA region (also bilaterally). He concluded that these "negative motor areas" most likely correspond to praxis regions. c. The dominant posterior fusiform gyrus which plays a crucial role in processing reading material. Stimulation of that area produces "alexia without agraphia". 3.He developed a new classification of epileptic seizures based exclusively on semiological ictal characteristics. With the development of the semiological seizure classification he also defined several new seizure types: a. Dialeptic seizures, b. Hypnopompic seizures, c. Hypomotor seizures. 4.Working with general epilepsy principles, he established the existence of 6 zones that characterize the epilepsies: the epileptogenic zone, the irritative zone, the seizure onset zone, the epileptogenic lesion, the symptomatogenic zone and functional deficit zone. 5.He described the ictal

  6. [Professor Hans Otto Lüders].

    PubMed

    Tsuji, Sadatoshi

    2014-11-01

    Professor Lüders has made significant contributions to Clinical Neurology and particularly to Epilepsy and Clinical Neurophysiology. Some of his most important contributions include the following: 1.He pioneered the use of chronically implanted, large plates of subdural electrodes in the presurgical evaluation of patient who were candidates for epilepsy surgery. These electrodes were used to record epileptic seizures and by electrical stimulation to establish the location of eloquent cortex. Lately he has also advocated the use in the USA of stereotactically implanted depth electrodes for presurgical evaluation of epilepsy patients who had deep seated epileptic foci which were impossible to assess with subdural electrodes. These techniques were imported from Europe. 2.Mapping studies with subdural electrodes led to the discovery of a number of cortical eloquent areas that had not been described before: a. The basal temporal language area located in the dominant fusiform gyrus. b. The "negative motor areas" located in the caudal region of the inferior frontal gyrus (bilaterally) and immediately in mesial frontal pre-SMA region (also bilaterally). He concluded that these "negative motor areas" most likely correspond to praxis regions. c. The dominant posterior fusiform gyrus which plays a crucial role in processing reading material. Stimulation of that area produces "alexia without agraphia". 3.He developed a new classification of epileptic seizures based exclusively on semiological ictal characteristics. With the development of the semiological seizure classification he also defined several new seizure types: a. Dialeptic seizures, b. Hypnopompic seizures, c. Hypomotor seizures. 4.Working with general epilepsy principles, he established the existence of 6 zones that characterize the epilepsies: the epileptogenic zone, the irritative zone, the seizure onset zone, the epileptogenic lesion, the symptomatogenic zone and functional deficit zone. 5.He described the ictal

  7. Van der Waals interaction in uniaxial anisotropic media

    NASA Astrophysics Data System (ADS)

    Kornilovitch, Pavel E.

    2013-01-01

    Van der Waals interactions between flat surfaces in uniaxial anisotropic media are investigated in the nonretarded limit. The main focus is the effect of nonzero tilt between the optical axis and the surface normal on the strength of the van der Waals attraction. General expressions for the van der Waals free energy are derived using the surface mode method and the transfer-matrix formalism. To facilitate numerical calculations a temperature-dependent three-band parameterization of the dielectric tensor of the liquid crystal 5CB is developed. A solid slab immersed in a liquid crystal experiences a van der Waals torque that aligns the surface normal relative to the optical axis of the medium. The preferred orientation is different for different materials. Two solid slabs in close proximity experience a van der Waals attraction that is strongest for homeotropic alignment of the intervening liquid crystal for all the materials studied. The results have implications for the stability of plate-like colloids in liquid crystal hosts.

  8. Van der Waals interaction in uniaxial anisotropic media.

    PubMed

    Kornilovitch, Pavel E

    2013-01-23

    Van der Waals interactions between flat surfaces in uniaxial anisotropic media are investigated in the nonretarded limit. The main focus is the effect of nonzero tilt between the optical axis and the surface normal on the strength of the van der Waals attraction. General expressions for the van der Waals free energy are derived using the surface mode method and the transfer-matrix formalism. To facilitate numerical calculations a temperature-dependent three-band parameterization of the dielectric tensor of the liquid crystal 5CB is developed. A solid slab immersed in a liquid crystal experiences a van der Waals torque that aligns the surface normal relative to the optical axis of the medium. The preferred orientation is different for different materials. Two solid slabs in close proximity experience a van der Waals attraction that is strongest for homeotropic alignment of the intervening liquid crystal for all the materials studied. The results have implications for the stability of plate-like colloids in liquid crystal hosts. PMID:23234868

  9. SediFoam: A general-purpose, open-source CFD-DEM solver for particle-laden flow with emphasis on sediment transport

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Xiao, Heng

    2016-04-01

    With the growth of available computational resource, CFD-DEM (computational fluid dynamics-discrete element method) becomes an increasingly promising and feasible approach for the study of sediment transport. Several existing CFD-DEM solvers are applied in chemical engineering and mining industry. However, a robust CFD-DEM solver for the simulation of sediment transport is still desirable. In this work, the development of a three-dimensional, massively parallel, and open-source CFD-DEM solver SediFoam is detailed. This solver is built based on open-source solvers OpenFOAM and LAMMPS. OpenFOAM is a CFD toolbox that can perform three-dimensional fluid flow simulations on unstructured meshes; LAMMPS is a massively parallel DEM solver for molecular dynamics. Several validation tests of SediFoam are performed using cases of a wide range of complexities. The results obtained in the present simulations are consistent with those in the literature, which demonstrates the capability of SediFoam for sediment transport applications. In addition to the validation test, the parallel efficiency of SediFoam is studied to test the performance of the code for large-scale and complex simulations. The parallel efficiency tests show that the scalability of SediFoam is satisfactory in the simulations using up to O(107) particles.

  10. DEM-based Approaches for the Identification of Flood Prone Areas

    NASA Astrophysics Data System (ADS)

    Samela, Caterina; Manfreda, Salvatore; Nardi, Fernando; Grimaldi, Salvatore; Roth, Giorgio; Sole, Aurelia

    2013-04-01

    The remarkable number of inundations that caused, in the last decades, thousands of deaths and huge economic losses, testifies the extreme vulnerability of many Countries to the flood hazard. As a matter of fact, human activities are often developed in the floodplains, creating conditions of extremely high risk. Terrain morphology plays an important role in understanding, modelling and analyzing the hydraulic behaviour of flood waves. Research during the last 10 years has shown that the delineation of flood prone areas can be carried out using fast methods that relay on basin geomorphologic features. In fact, the availability of new technologies to measure surface elevation (e.g., GPS, SAR, SAR interferometry, RADAR and LASER altimetry) has given a strong impulse to the development of Digital Elevation Models (DEMs) based approaches. The identification of the dominant topographic controls on the flood inundation process is a critical research question that we try to tackle with a comparative analysis of several techniques. We reviewed four different approaches for the morphological characterization of a river basin with the aim to provide a description of their performances and to identify their range of applicability. In particular, we explored the potential of the following tools. 1) The hydrogeomorphic method proposed by Nardi et al. (2006) which defines the flood prone areas according to the water level in the river network through the hydrogeomorphic theory. 2) The linear binary classifier proposed by Degiorgis et al. (2012) which allows distinguishing flood-prone areas using two features related to the location of the site under exam with respect to the nearest hazard source. The two features, proposed in the study, are the length of the path that hydrologically connects the location under exam to the nearest element of the drainage network and the difference in elevation between the cell under exam and the final point of the same path. 3) The method by

  11. Sediment budget estimation in a small torrential catchment using DEM of difference approach

    NASA Astrophysics Data System (ADS)

    Bezak, Nejc; Grigillo, Dejan; Rusjan, Simon; Šraj, Mojca; Urbančič, Tilen; Kozmus Trajkovski, Klemen; Petrovič, Dušan; Mikoš, Matjaž

    2015-04-01

    The aim of the study was to estimate the sediment budget (net erosion change) in a small torrential catchment using the DEM of difference (DoD) approach. The Kuzlovec torrent (~ 0.7 km2; in the Gradaščica River catchment) is located approximately 20 km west of the City of Ljubljana and is part of the Sava River basin. The elevation ranges between 394 and 847 m.a.s.l, the mean catchment slope is 27.3°, the mean annual precipitation typically ranges between 1600 to 1800 mm, forest covers more than 85% of the area, and the predominant soil type is Rendzic Leptosol (according to the FAO classification). Using the Terestrical Laser Scanning (TLS) a digital terrain model (DTM) with a 5 cm grid cell was obtained. A smaller (about 25 m wide and 160 m long) specific study site with a mean slope of 37° was selected in order to ensure the high quality of data. A high resolution (several million points) surveys were performed in April 2013 and August 2014. In the night from 4th to 5th of August 2014 an extreme flash flood happened in the investigated area. Three tipping bucket rain gauges and one disdrometer, which are located in the Gradaščica River catchment, measured 110 to 185 mm of rainfall in less than 10 hours. Two rain gauges measured about 110 mm, one rain gauge (the closest to the Kuzloved torrent) recorded approximately 140 mm of rainfall, while the disdrometer measured 185 mm of rainfall. The estimated return period of this rainfall event (based on the rain gauge data) was between 100 and 250 years, however based on the disdrometer observations the return period was larger than 250 years. The Gumbel distribution was used in order to construct the intensity-duration-frequency (IDF) relationship and the data from 1976 to 2008 was used for this purpose. Furthermore, the maximum one minute rainfall intensity measured by the disdrometer was 288 mm/h. This high rainfall intensities triggered several shallow landslides and caused intense soil erosion processes

  12. Hydrography change detection: the usefulness of surface channels derived From LiDAR DEMs for updating mapped hydrography

    USGS Publications Warehouse

    Poppenga, Sandra K.; Gesch, Dean B.; Worstell, Bruce B.

    2013-01-01

    The 1:24,000-scale high-resolution National Hydrography Dataset (NHD) mapped hydrography flow lines require regular updating because land surface conditions that affect surface channel drainage change over time. Historically, NHD flow lines were created by digitizing surface water information from aerial photography and paper maps. Using these same methods to update nationwide NHD flow lines is costly and inefficient; furthermore, these methods result in hydrography that lacks the horizontal and vertical accuracy needed for fully integrated datasets useful for mapping and scientific investigations. Effective methods for improving mapped hydrography employ change detection analysis of surface channels derived from light detection and ranging (LiDAR) digital elevation models (DEMs) and NHD flow lines. In this article, we describe the usefulness of surface channels derived from LiDAR DEMs for hydrography change detection to derive spatially accurate and time-relevant mapped hydrography. The methods employ analyses of horizontal and vertical differences between LiDAR-derived surface channels and NHD flow lines to define candidate locations of hydrography change. These methods alleviate the need to analyze and update the nationwide NHD for time relevant hydrography, and provide an avenue for updating the dataset where change has occurred.

  13. Co-seismic landslide topographic analysis based on multi-temporal DEM-A case study of the Wenchuan earthquake.

    PubMed

    Ren, Zhikun; Zhang, Zhuqi; Dai, Fuchu; Yin, Jinhui; Zhang, Huiping

    2013-01-01

    Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively.

  14. Using the DEM-based Xin'anjiang hydrologic model to simulate hydrologic characteristics in SiheRiver Basin

    NASA Astrophysics Data System (ADS)

    Qi, C. S.; Liu, D. D.; Tan, L. Y.; Zhu, L.

    2016-08-01

    In order to consider the spatial distribution of precipitation, the basin is generally divided by the Thiessen polygon method with the same concentration parameters in all divided units in Xin'anjiang hydrologic model, without considering the impact of terrain. The runoff concentration characteristics depend on the terrain condition to a great extent.Therefore, it is necessary to consider the impact of terrain condition in the model. The purpose of this article is to consider the impact of terrain condition to improve the Xin'anjiang hydrologic model. The basin is divided, and then the slopes of the divided sub-basins and the distances to the basin outlet are extracted based on the DEM. Twofunction relations between the terrain slope and the runoff concentration are established, and the application results of Sihe river basin show that the Xin'anjiang hydrologic model simulation precision is improved greatly based on the DEM,and it is more reasonable that the recession coefficient and the average gradient of the basin is an exponential relationship.

  15. Correction of the SRTMGL1 Space-Borne Dem and Flooding Dynamics On The Lower Amazon Floodplain

    NASA Astrophysics Data System (ADS)

    Satgé, F.; Pinel, S. S.; Bonnet, M. P.; Moreira, D. M.; Santos da Silva, J.; Calmant, S.; Seyler, F.

    2015-12-01

    Modeling floods events across large floodplains is challenging because flows respond to dynamic hydraulic controls from several water sources, complex geomorphology, and vegetation. In the Amazon basin, the recently liberated SRTM Global 1 arc-second (SRTMGL1) remains the best topographic information in view of hydrodynamic modeling purposes. Its accuracy is however hindered by errors partly due to vegetation leading to erroneous simulations. Previous efforts to remove the vegetation signal do not account for its spatial variability or relied on upon single assumed percentage of penetration of the SRTM signal. In this study, we propose to a systematic approach, over an Amazonian floodplain (Fig. 1), to remove the vegetation signal, which consider its heterogeneity combining estimates of vegetation height and land cover map. We improve this approach by interpolating first results with drainage network, field and altimetry data to obtain a hydrological conditioned DEM. Averaged interferometric and vegetation bias over the forest zone were found to be -2.0 m and 7.4 m, respectively (Fig. 2). Comparing original DEM and corrected one, vertical validation against Ground Control Points shows a RMSE diminution of 64%. Floodplain inundation was simulated using the 3D model IPH-ECO model. Flood extent accuracy, controlled against ALOS-PALSAR and JERS-1 images, stresses improvements at low and high waters (Fig. 3). This study also highlights that a ground truth drainage network as unique input during the interpolation permits reaching reasonable in terms of flood extent and hydrological characteristics.

  16. Catchment properties in the Kruger National Park derived from the new TanDEM-X Intermediate Digital Elevation Model (IDEM)

    NASA Astrophysics Data System (ADS)

    Baade, J.; Schmullius, C.

    2015-04-01

    Digital Elevation Models (DEM) represent fundamental data for a wide range of Earth surface process studies. Over the past years the German TanDEM-X mission acquired data for a new, truly global Digital Elevation Model with unpreceded geometric resolution, precision and accuracy. First processed data sets (i. e. IDEM) with a geometric resolution of 0.4 to 3 arcsec have been made available for scientific purposes. This includes four 1° x 1° tiles covering the Kruger National Park in South Africa. Here we document the results of a local scale IDEM validation exercise utilizing RTK-GNSS-based ground survey points from a dried out reservoir basin and its vicinity characterized by pristine open Savanna vegetation. Selected precursor data sets (SRTM1, SRTM90, ASTER-GDEM2) were included in the analysis and highlight the immense progress in satellite-based Earth surface surveying over the past two decades. Surprisingly, the high precision and accuracy of the IDEM data sets have only little impact on the delineation of watersheds and the calculation of catchment size. But, when it comes to the derivation of topographic catchment properties (e.g. mean slope, etc.) the high resolution of the IDEM04 is of crucial importance, if - from a geomorphologist's view - it was not for the disturbing vegetation.

  17. Effective Thermal Property Estimation of Unitary Pebble Beds Based on a CFD-DEM Coupled Method for a Fusion Blanket

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Chen, Youhua; Huang, Kai; Liu, Songlin

    2015-12-01

    Lithium ceramic pebble beds have been considered in the solid blanket design for fusion reactors. To characterize the fusion solid blanket thermal performance, studies of the effective thermal properties, i.e. the effective thermal conductivity and heat transfer coefficient, of the pebble beds are necessary. In this paper, a 3D computational fluid dynamics discrete element method (CFD-DEM) coupled numerical model was proposed to simulate heat transfer and thereby estimate the effective thermal properties. The DEM was applied to produce a geometric topology of a prototypical blanket pebble bed by directly simulating the contact state of each individual particle using basic interaction laws. Based on this geometric topology, a CFD model was built to analyze the temperature distribution and obtain the effective thermal properties. The current numerical model was shown to be in good agreement with the existing experimental data for effective thermal conductivity available in the literature. supported by National Special Project for Magnetic Confined Nuclear Fusion Energy of China (Nos. 2013GB108004, 2015GB108002, 2014GB122000 and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

  18. A web-based platform for simulating seismic wave propagation in 3D shallow Earth models with DEM surface topography

    NASA Astrophysics Data System (ADS)

    Luo, Cong; Friederich, Wolfgang

    2016-04-01

    Realistic shallow seismic wave propagation simulation is an important tool for studying induced seismicity (e.g., during geothermal energy development). However over a long time, there is a significant problem which constrains computational seismologists from performing a successful simulation conveniently: pre-processing. Conventional pre-processing has often turned out to be inefficient and unrobust because of the miscellaneous operations, considerable complexity and insufficiency of available tools. An integrated web-based platform for shallow seismic wave propagation simulation has been built. It is aiming at providing a user-friendly pre-processing solution, and cloud-based simulation abilities. The main features of the platform for the user include: revised digital elevation model (DEM) retrieving and processing mechanism; generation of multi-layered 3D shallow Earth model geometry (the computational domain) with user specified surface topography based on the DEM; visualization of the geometry before the simulation; a pipeline from geometry to fully customizable hexahedral element mesh generation; customization and running the simulation on our HPC; post-processing and retrieval of the results over cloud. Regarding the computational aspect, currently the widely accepted specfem3D is chosen as the computational package; packages using different types of elements can be integrated as well in the future. According to our trial simulation experiments, this web-based platform has produced accurate waveforms while significantly simplifying and enhancing the pre-processing and improving the simulation success rate.

  19. Co-seismic landslide topographic analysis based on multi-temporal DEM-A case study of the Wenchuan earthquake.

    PubMed

    Ren, Zhikun; Zhang, Zhuqi; Dai, Fuchu; Yin, Jinhui; Zhang, Huiping

    2013-01-01

    Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively. PMID:24171155

  20. An Investigation of Transgressive Deposits in Late Pleistocene Lake Bonneville using GPR and UAV-produced DEMs.

    NASA Astrophysics Data System (ADS)

    Schide, K.; Jewell, P. W.; Oviatt, C. G.; Jol, H. M.

    2015-12-01

    Lake Bonneville was the largest of the Pleistocene pluvial lakes that once filled the Great Basin of the interior western United States. Its two most prominent shorelines, Bonneville and Provo, are well documented but many of the lake's intermediate shoreline features have yet to be studied. These transgressive barriers and embankments mark short-term changes in the regional water budget and thus represent a proxy for local climate change. The internal and external structures of these features are analyzed using the following methods: ground penetrating radar, 5 meter auto-correlated DEMs, 1-meter DEMs generated from LiDAR, high-accuracy handheld GPS, and 3D imagery collected with an unmanned aerial vehicle. These methods in mapping, surveying, and imaging provide a quantitative analysis of regional sediment availability, transportation, and deposition as well as changes in wave and wind energy. These controls help define climate thresholds and rates of landscape evolution in the Great Basin during the Pleistocene that are then evaluated in the context of global climate change.

  1. Drainage density, slope angle, and relative basin position in Japanese bare lands from high-resolution DEMs

    NASA Astrophysics Data System (ADS)

    Lin, Zhou; Oguchi, Takashi

    2004-12-01

    Relationships between drainage density and slope angle for three bare lands in Japan were analyzed with special attention to channels at early erosion stages and channels in a badland-type terrain. Two of the bare lands were caused by volcanic eruptions 1 or 30-40 years ago, and the other one is a landslide scar formed more than 100 years ago. Raster digital elevation models (DEMs) with a 1-m resolution and ortho aerial photos were generated using digital photogrammetry to enable detailed stream-net extraction and topographic analyses. Data for drainage density, slope angle, and relative height for 88 subwatersheds were obtained from the DEMs and derived stream-nets. The relationship between drainage density and slope angle for each subwatershed can be divided into two types: downward sloping and convex upward. Although previous studies suggested that drainage density positively correlates with slope angle if overland flow is dominant, this correlation seldom occurs in the study areas. The two types of drainage density-slope angle relationships correspond to differing channelization stages that reflect the extension and integration of existing channels, as well as the formation of new low-order streams in response to base-level lowering. The location of subwatersheds within each study area seems to play a major role in determining the stages of channel development and, in turn, the types of drainage density-slope angle relationships.

  2. Van der woude syndrome with short review of the literature.

    PubMed

    Deshmukh, Pallavi K; Deshmukh, Kiran; Mangalgi, Anand; Patil, Subhash; Hugar, Deepa; Kodangal, Saraswathi Fakirappa

    2014-01-01

    Van der Woude syndrome (VWS) is a rare autosomal dominant condition with high penetrance and variable expression. Clinical manifestation of this autosomal dominant clefting syndrome includes bilateral midline lower lip pits, cleft lip, and cleft palate along with hypodontia. These congenital lip pits appear as a malformation in the vermilion border of the lip, with or without excretion. Discomfort caused by spontaneous or induced drainage of saliva/mucus when pressure is applied or during a meal as well as poor aesthetic match is one of the main complaints of patients with congenital lip fistula. The pits are treated by surgical resection. Dentists should be aware of the congenital lip pits as in Van der Woude syndrome because they have been reported to be associated with a variety of malformations or other congenital disorders. Here, the authors report a rare case of Van der Woude syndrome with short review of the literature. PMID:25050184

  3. A cartography of the van der Waals territories.

    PubMed

    Alvarez, Santiago

    2013-06-28

    The distribution of distances from atoms of a particular element E to a probe atom X (oxygen in most cases), both bonded and intermolecular non-bonded contacts, has been analyzed. In general, the distribution is characterized by a maximum at short E···X distances corresponding to chemical bonds, followed by a range of unpopulated distances--the van der Waals gap--and a second maximum at longer distances--the van der Waals peak--superimposed on a random distribution function that roughly follows a d(3) dependence. The analysis of more than five million interatomic "non-bonded" distances has led to the proposal of a consistent set of van der Waals radii for most naturally occurring elements, and its applicability to other element pairs has been tested for a set of more than three million data, all of them compared to over one million bond distances.

  4. Spontaneous stacking faults in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Boussinot, G.

    2016-08-01

    The rapid developments in the manipulation of two-dimensional monoatomic layers such as graphene or h-BN allow one to create heterostructures consisting of possibly many chemically different layers, stacked owing to van der Waals attraction. We propose a Frenkel-Kontorova model including a transverse degree of freedom in order to describe local deformations in these heterostructures. We study the case where two dissimilar monolayers are alternatively stacked, and find that stacking faults may emerge spontaneously for a large enough number of stacked layers as a result of the competition between adhesion and elastic energies. This symmetry-breaking transition should become of fundamental importance for the description of three-dimensional van der Waals heterostructures as soon as a precise control on the lattice orientation of the van der Waals layers is achieved.

  5. van der Waals interactions between excited atoms in generic environments

    NASA Astrophysics Data System (ADS)

    Barcellona, Pablo; Passante, Roberto; Rizzuto, Lucia; Buhmann, Stefan Yoshi

    2016-07-01

    We consider the van der Waals force involving excited atoms in general environments, constituted by magnetodielectric bodies. We develop a dynamical approach studying the dynamics of the atoms and the field, mutually coupled. When only one atom is excited, our dynamical theory suggests that for large distances the van der Waals force acting on the ground-state atom is monotonic, while the force acting in the excited atom is spatially oscillating. We show how this latter force can be related to the known oscillating Casimir-Polder force on an excited atom near a (ground-state) body. Our force also reveals a population-induced dynamics: for times much larger that the atomic lifetime the atoms will decay to their ground states leading to the van der Waals interaction between ground-state atoms.

  6. Collisional stabilization of van der Waals states of ozone.

    PubMed

    Ivanov, Mikhail V; Babikov, Dmitri

    2011-05-01

    The mixed quantum-classical theory developed earlier [M. Ivanov and D. Babikov, J. Chem. Phys. 134, 144107 (2011)] is employed to treat the collisional energy transfer and the ro-vibrational energy flow in a recombination reaction that forms ozone. Assumption is that the van der Waals states of ozone are formed in the O + O(2) collisions, and then stabilized into the states of covalent well by collisions with bath gas. Cross sections for collision induced dissociation of van der Waals states of ozone, for their stabilization into the covalent well, and for their survival in the van der Waals well are computed. The role these states may play in the kinetics of ozone formation is discussed.

  7. Collisional stabilization of van der Waals states of ozone

    NASA Astrophysics Data System (ADS)

    Ivanov, Mikhail V.; Babikov, Dmitri

    2011-05-01

    The mixed quantum-classical theory developed earlier [M. Ivanov and D. Babikov, J. Chem. Phys. 134, 144107 (2011)] is employed to treat the collisional energy transfer and the ro-vibrational energy flow in a recombination reaction that forms ozone. Assumption is that the van der Waals states of ozone are formed in the O + O2 collisions, and then stabilized into the states of covalent well by collisions with bath gas. Cross sections for collision induced dissociation of van der Waals states of ozone, for their stabilization into the covalent well, and for their survival in the van der Waals well are computed. The role these states may play in the kinetics of ozone formation is discussed.

  8. Van der Waals stacked 2D layered materials for optoelectronics

    NASA Astrophysics Data System (ADS)

    Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.

    2016-06-01

    The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.

  9. The Economics of van der Waals Force Engineering

    NASA Astrophysics Data System (ADS)

    Pinto, Fabrizio

    2008-01-01

    As micro-electro-mechanical system (MEMS) fabrication continues on an ever-decreasing scale, new technological challenges must be successfully negotiated if Moore's Law is to be an even approximately valid model of the future of device miniaturization. Among the most significant obstacles is the existence of strong surface forces related to quantum mechanical van der Waals interatomic interactions, which rapidly diverge as the distance between any two neutral boundaries decreases. The van der Waals force is a contributing factor in several device failures and limitations, including, for instance, stiction and oscillator non-linearities. In the last decade, however, it has been conclusively shown that van der Waals forces are not just a MEMS limitation but can be engineered in both magnitude and sign so as to enable classes of proprietary inventions which either deliver novel capabilities or improve upon existing ones. The evolution of van der Waals force research from an almost exclusively theoretical field in quantum-electro-dynamics to an enabling nanotechnology discipline represents a useful example of the ongoing paradigm shift from government-centered to private-capital funded R&D in cutting-edge physics leading to potentially profitable products. In this paper, we discuss the reasons van der Waals force engineering may lead to the creation of thriving markets both in the short and medium terms by highlighting technical challenges that can be competitively addressed by this novel approach. We also discuss some notable obstacles to the cultural transformation of the academic research community required for the emergence of a functional van der Waals force engineering industry worldwide.

  10. Curves of growth for van der Waals broadened spectral lines

    NASA Technical Reports Server (NTRS)

    Park, C.

    1980-01-01

    Curves of growth are evaluated for a spectral line broadened by the van der Waals interactions during collisions. The growth of the equivalent widths of such lines is shown to be dependent on the product of the perturber density and the 6/10 power of the van der Waals potential coefficient. When the parameter is small, the widths grow as the 1/2 power of the optical depth as they do for the Voigt profile: but when the parameter is large, they grow as 2/3 power and, hence, faster than the Voigt profile. An approximate analytical expression for the computed growth characteristics is given.

  11. A FEM-DEM technique for studying the motion of particles in non-Newtonian fluids. Application to the transport of drill cuttings in wellbores

    NASA Astrophysics Data System (ADS)

    Celigueta, Miguel Angel; Deshpande, Kedar M.; Latorre, Salvador; Oñate, Eugenio

    2016-04-01

    We present a procedure for coupling the finite element method (FEM) and the discrete element method (DEM) for analysis of the motion of particles in non-Newtonian fluids. Particles are assumed to be spherical and immersed in the fluid mesh. A new method for computing the drag force on the particles in a non-Newtonian fluid is presented. A drag force correction for non-spherical particles is proposed. The FEM-DEM coupling procedure is explained for Eulerian and Lagrangian flows, and the basic expressions of the discretized solution algorithm are given. The usefulness of the FEM-DEM technique is demonstrated in its application to the transport of drill cuttings in wellbores.

  12. Low-altitude remote sensing dataset of DEM and RGB mosaic for AB corridor on July 13 2013 and L2 corridor on July 21 2013

    DOE Data Explorer

    Baptiste Dafflon

    2015-04-07

    Low-altitude remote sensing dataset including DEM and RGB mosaic for AB (July 13 2013) and L2 corridor (July 21 2013).Processing flowchart for each corridor:Ground control points (GCP, 20.3 cm square white targets, every 20 m) surveyed with RTK GPS. Acquisition of RGB pictures using a Kite-based platform. Structure from Motion based reconstruction using hundreds of pictures and GCP coordinates. Export of DEM and RGB mosaic in geotiff format (NAD 83, 2012 geoid, UTM zone 4 north) with pixel resolution of about 2 cm, and x,y,z accuracy in centimeter range (less than 10 cm). High-accuracy and high-resolution inside GCPs zone for L2 corridor (500x20m), AB corridor (500x40) DEM will be updated once all GCPs will be measured. Only zones between GCPs are accurate although all the mosaic is provided.

  13. Web-gestütztes Social Networking am Beispiel der Plattform Wissensmanagement"

    NASA Astrophysics Data System (ADS)

    Lindstaedt, Stefanie; Thurner, Claudia

    Anhand der Plattform Wissensmanagement, der größten deutschsprachigen Community im Themenfeld Wissensmanagement, werden organisationale Rahmenbedingungen, technische Werkzeuge und Rollen der Moderatorin diskutiert, die Bedingungen für den erfolgreichen Betrieb einer Community im Web 2.0 sind. Weiters wird dargestellt, wie Communities für das betriebliche Wissensmanagement eingesetzt werden können.

  14. Landslide-dammed lakes detection via ALOS/PALSAR InSAR DEM: A case study of the Iwate-Miyagi Nairiku earthquake

    NASA Astrophysics Data System (ADS)

    Asaka, Tomohito; Yamamoto, Yoshiyuki; Iwashita, Keishi; Kudou, Katsuteru; Fujii, Hisao; Nishikawa, Hajime; Sensing Specialist Yukihiro Suzuoki, Remote

    On 14th June 2008, the Japan Meteorological Agency recorded a 7.2 magnitude (Richter scale) earthquake with an epicenter depth of 8 km in the southern Iwate prefecture of the Tohoku region of Japan. In the hardest hit prefectures of Iwate and Miyagi, the earthquake produced 15 new landslide-dammed lakes; a phenomenon common when the earthquake hypocenter is within inland areas. In our last study, we demonstrated that interferometric SAR (InSAR) technique can detect surface displacements within centimeter accuracy and create detailed three-dimensional terrain information. In this study, we developed a new methodology to detect landslide-dammed lakes using Digital Drainage Models (DDMs) generated from the DEM's cre-ated with InSAR data. Using our technique, small scale topographical change was detected by comparing pre-earthquake DEM's such as created from the Shuttle Radar Topographic Mission (SRTM) data and post-earthquake DEM's created from the Advanced Land Observing System (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data. Pre-and post-earthquake changes in the drainage networks were detected by comparing DDM features derived from an existing DEM to DDM features derived from a post-earthquake DEM created from ALOS InSAR data. It was verified that landslide-dammed lakes were detected specifically in the area where drainage network with more than three of the river-order computed from DDM's shifted before and after the earthquake. Thus, InSAR DEM generated from ALOS/PALSAR can provide timely and useful spatial information for detecting landslide-dammed lakes.

  15. Amundsen Sea sector ice shelf thickness, melt rates, and inland response from annual high-resolution DEM mosaics

    NASA Astrophysics Data System (ADS)

    Shean, D. E.; Joughin, I. R.; Smith, B. E.; Alexandrov, O.; Moratto, Z.; Porter, C. C.; Morin, P. J.

    2014-12-01

    Significant grounding line retreat, acceleration, and thinning have occurred along the Amundsen Sea sector of West Antarctica in recent decades. These changes are driven primarily by ice-ocean interaction beneath ice shelves, but existing observations of the spatial distribution, timing, and magnitude of ice shelf melt are limited. Using the NASA Ames Stereo Pipeline, we generated digital elevation models (DEMs) with ~2 m posting from all ~450 available WorldView-1/2 along-track stereopairs for the Amundsen Sea sector. A novel iterative closest point algorithm was used to coregister DEMs to filtered Operation IceBridge ATM/LVIS data and ICESat-1 GLAS data, offering optimal sub-meter horizontal/vertical accuracy. The corrected DEMs were used to produce annual mosaics for the entire ~500x700 km region with focused, sub-annual products for ice shelves and grounding zones. These mosaics provide spatially-continuous measurements of ice shelf topography with unprecedented detail. Using these data, we derive estimates of ice shelf thickness for regions in hydrostatic equilibrium and map networks of sub-shelf melt channels for the Pine Island (PIG), Thwaites, Crosson, and Dotson ice shelves. We also document the break-up of the Thwaites ice shelf and PIG rift evolution leading up to the 2013 calving event. Eulerian difference maps document 2010-2014 thinning over fast-flowing ice streams and adjacent grounded ice. These data reveal the greatest thinning rates over the Smith Glacier ice plain and slopes beyond the margins of the fast-flowing PIG trunk. Difference maps also highlight the filling of at least two subglacial lakes ~30 km upstream of the PIG grounding line in 2011. Lagrangian difference maps reveal the spatial distribution of ice shelf thinning, which can primarily be attributed to basal melt. Preliminary results show focused ice shelf thinning within troughs and large basal channels, especially along the western margin of the Dotson ice shelf. These new data

  16. Statistical complexity, virial expansion, and van der Waals equation

    NASA Astrophysics Data System (ADS)

    Pennini, F.; Plastino, A.

    2016-09-01

    We investigate the notion of LMC statistical complexity with regards to a real gas and in terms of the second virial coefficient. The ensuing results are applied to the van der Waals equation. Interestingly enough, one finds a complexity-interpretation for the associated phase transition.

  17. Excited nucleon as a van der Waals system of partons

    SciTech Connect

    Jenkovszky, L. L.; Muskeyev, A. O. Yezhov, S. N.

    2012-06-15

    Saturation in deep inelastic scattering (DIS) and deeply virtual Compton scattering (DVCS) is associated with a phase transition between the partonic gas, typical of moderate x and Q{sup 2}, and partonic fluid appearing at increasing Q{sup 2} and decreasing Bjorken x. We suggest the van der Waals equation of state to describe properly this phase transition.

  18. Analysis of the seasonal and interannual evolution of Jakobshavn Isbrae from 2010-2013 using high spatial/temporal resolution DEM and velocity data

    NASA Astrophysics Data System (ADS)

    Shean, D. E.; Joughin, I. R.; Smith, B. E.; Moratto, Z. M.; Alexandrov, O.; Floricioiu, D.; Morin, P. J.; Porter, C. C.; Beyer, R. A.; Fong, T.

    2013-12-01

    Greenland's large marine-terminating outlet glaciers have displayed marked retreat, speedup, and thinning in recent decades. Jakobshavn Isbrae, one of Greenland's largest outlet glaciers, has retreated ~15 km, accelerated ~150%, and thinned ~200 m since the early 1990s. Here, we present the first comprehensive analysis of high spatial (~2-5 m/px) and temporal (daily-monthly) resolution elevation and velocity data for Jakobshavn from 7/2010 to 7/2013. We have developed an automated processing pipeline using open-source software (Ames Stereo Pipeline, GDAL/OGR, NumPy/SciPy, etc.) to produce orthoimage, digital elevation model (DEM), and surface velocity products from DigitalGlobe WorldView-1/2 stereo imagery (~0.5 m/px, ~17 km swath width). Our timeseries consists of 35 WV DEMs (~2-4 m/px) covering the lower trunks of the main+north branches and fjord, but also extending >110 km inland. We supplement this record with 7 TanDEM-X DEMs (~5 m/px, ~35 km swath width) between 6/2011-9/2012. Elevation data from IceBridge ATM/LVIS, ICESat GLAS, and GPS campaigns provide absolute control data over fixed surfaces (i.e., exposed bedrock). Observed WV DEM offsets are consistent with DigitalGlobe's published value of 5.0 m CE90/LE90 horizontal/vertical accuracy. After DEM co-registration, we observe sub-meter horizontal and vertical absolute accuracy. Velocity data are derived from TerraSAR-X data with 11 day repeat interval. Supplemental velocity data are derived through correlation of high-resolution WV DEM/image data. The contemporaneous DEM and velocity data provide full 3D displacement vectors for each time interval, allowing for the analysis of both Eulerian and Lagrangian elevation change. The lower trunk of Jakobshavn displays significant seasonal velocity variations, with recent rates of ~8 km/yr during winter to >17 km/yr during summer. DEM data show corresponding elevation changes of -30 to -45 m in summer and +15 to +20 m in winter, corresponding to integrated volumes

  19. DEM-PFV analysis of solid-fluid transition in granular sediments under the action of waves

    NASA Astrophysics Data System (ADS)

    Catalano, E.; Chareyre, B.; Barthélémy, E.

    2013-06-01

    Solid-fluid transition is a very active area of investigations. It is linked to many applications in geomechanics and near-shore or off-shore engineering. Micromechanical models can give useful insight into the governing mechanisms of this phenomenon, provided they can reflect the role of pore fluids accurately. We present the application of a new hydromechanical model, combining the Discrete Element Method (DEM) to a flow model based on a pore-scale discretization in finite volumes (PFV) for incompressible pore fluids, to simulate the response of near-shore granular sediments subjected to the action of stationary waves. The model reproduces a wide range of physical processes observed in the experiments, including temporary liquefaction events.

  20. The evaluation of unmanned aerial system-based photogrammetry and terrestrial laser scanning to generate DEMs of agricultural watersheds

    NASA Astrophysics Data System (ADS)

    Ouédraogo, Mohamar Moussa; Degré, Aurore; Debouche, Charles; Lisein, Jonathan

    2014-06-01

    Agricultural watersheds tend to be places of intensive farming activities that permanently modify their microtopography. The surface characteristics of the soil vary depending on the crops that are cultivated in these areas. Agricultural soil microtopography plays an important role in the quantification of runoff and sediment transport because the presence of crops, crop residues, furrows and ridges may impact the direction of water flow. To better assess such phenomena, 3-D reconstructions of high-resolution agricultural watershed topography are essential. Fine-resolution topographic data collection technologies can be used to discern highly detailed elevation variability in these areas. Knowledge of the strengths and weaknesses of existing technologies used for data collection on agricultural watersheds may be helpful in choosing an appropriate technology. This study assesses the suitability of terrestrial laser scanning (TLS) and unmanned aerial system (UAS) photogrammetry for collecting the fine-resolution topographic data required to generate accurate, high-resolution digital elevation models (DEMs) in a small watershed area (12 ha). Because of farming activity, 14 TLS scans (≈ 25 points m- 2) were collected without using high-definition surveying (HDS) targets, which are generally used to mesh adjacent scans. To evaluate the accuracy of the DEMs created from the TLS scan data, 1098 ground control points (GCPs) were surveyed using a real time kinematic global positioning system (RTK-GPS). Linear regressions were then applied to each DEM to remove vertical errors from the TLS point elevations, errors caused by the non-perpendicularity of the scanner's vertical axis to the local horizontal plane, and errors correlated with the distance to the scanner's position. The scans were then meshed to generate a DEMTLS with a 1 × 1 m spatial resolution. The Agisoft PhotoScan and MicMac software packages were used to process the aerial photographs and generate a DEMPSC

  1. Morphotectonic control of the Białka drainage basin (Central Carpathians): Insights from DEM and morphometric analysis.

    NASA Astrophysics Data System (ADS)

    Wołosiewicz, Bartosz

    2016-06-01

    The Białka river valley is directly related to a deep NNW-SSE oriented fault zone. According to the results of previous morphometric analyses, the Białka drainage basin is one of the most tectonically active zones in the Central Carpathians. It is also located within an area of high seismic activity. In this study Digital Elevation Model (DEM) based, morphometric analyses were used to investigate the morphotectonic conditions of the watershed. The results reveal the relationships between the main tectonic feature and the landforms within the research area. The lineaments, as obtained from the classified aspect map, seem to coincide with the orientation of the main structures as well as the trends revealed by the theoretical Riedel-Skempton shear model. Base-level and isolong maps support the conclusion that the Białka and Biały Dunajec fault zones exert a strong influence on the morphology of the adjacent area.

  2. Das Universum der Sterne. Himmelsbeobachtungen und Streifzüge durch die moderne Astronomie.

    NASA Astrophysics Data System (ADS)

    Rowan-Robinson, M.

    This book is a German translation, by M. Röser, of the English original published in 1990 (see 52.003.046). Contents: 1. Der Halleysche Komet. 2. Alpha Centauri - Der sonnennächste Stern. 3. Sirius und sein Begleiter, ein Weißer Zwerg. 4. Polaris - Der Polarstern. 5. Wega - Ein Planetensystem im Entstehen? 6. Mira - Der erste bekannte veränderliche Stern. 7. Der Ring-Nebel - "Todeskampf" eines sonnenähnlichen Sterns. 8. Der Orion-Nebel - Die Geburt neuer Sterne. 9. Delta Cephei - Die Meßlatte des Weltalls. 10. Algol - Der Teufelsstern. 11. Nova Aquilae - Der neue Stern von 1918. 12. Der Krebs-Nebel - Die Supernova des Jahres 1054. 13. Die Hyaden und Plejaden - Sternhaufen. 14. Die Milchstraße - Unsere Galaxis. 15. Die Magellanschen Wolken - Unsere Nachbarn im Weltall. 16. Der Andromeda-Nebel - Zwilling unserer Galaxis. 17. Messier 87 - Eine Radiogalaxie. 18. 3C 273 - Rätselhafter Quasar. 19. Messier 82 - Eine "Starburst"-Galaxie. 20. Der Virgo-Haufen - Ein reicher Galaxienhaufen. 21. Das Universum.

  3. Einstellung und Wissen von Lehramtsstudierenden zur Evolution - ein Vergleich zwischen Deutschland und der Türkei

    NASA Astrophysics Data System (ADS)

    Graf, Dittmar; Soran, Haluk

    Es wird eine Untersuchung vorgestellt, in der Wissen und Überzeugungen von Lehramtsstudierenden aller Fächer zum Thema Evolution an zwei Universitäten in Deutschland und der Türkei erhoben worden sind. Die Befragung wurde in Dortmund und in Ankara durchgeführt. Es stellte sich heraus, dass ausgeprägte Defizite im Verständnis der Evolutionsmechanismen herrschen. Viele Studierende, insbesondere aus der Türkei, sind nicht von der Faktizität der Evolution überzeugt. Dies gilt sowohl für Studierende mit Fach Biologie als auch für Studierende mit anderen Fächern. Näher untersucht worden sind die Faktoren, die die Überzeugungen zur Evolution beeinflussen können, was ja in Anbetracht der hohen Ablehnungsrate der Evolution von besonderem Interesse ist. Das Vertrauen in die Wissenschaft spielt hierbei eine besondere Rolle: Wer der Wissenschaft vertraut, ist auch eher von der Evolution überzeugt, als diejenigen, die skeptisch gegenüber der Wissenschaft sind.

  4. Inter-annual surface evolution of an Antarctic blue-ice moraine using multi-temporal DEMs

    NASA Astrophysics Data System (ADS)

    Westoby, M. J.; Dunning, S. A.; Woodward, J.; Hein, A. S.; Marrero, S. M.; Winter, K.; Sugden, D. E.

    2015-11-01

    Multi-temporal and fine resolution topographic data products are being increasingly used to quantify surface elevation change in glacial environments. In this study, we employ 3-D digital elevation model (DEM) differencing to quantify the topographic evolution of a blue-ice moraine complex in front of Patriot Hills, Heritage Range, Antarctica. Terrestrial laser scanning (TLS) was used to acquire multiple topographic datasets of the moraine surface at the beginning and end of the austral summer season in 2012/2013 and during a resurvey field campaign in 2014. A complementary topographic dataset was acquired at the end of season 1 through the application of Structure-from-Motion (SfM) photogrammetry to a set of aerial photographs taken from an unmanned aerial vehicle (UAV). Three-dimensional cloud-to-cloud differencing was undertaken using the Multiscale Model to Model Cloud Comparison (M3C2) algorithm. DEM differencing revealed net uplift and lateral movement of the moraine crests within season 1 (mean uplift ∼ 0.10 m), with lowering of a similar magnitude in some inter-moraine depressions and close to the current ice margin. Our results indicate net uplift across the site between seasons 1 and 2 (mean 0.07 m). This research demonstrates that it is possible to detect dynamic surface topographical change across glacial moraines over short (annual to intra-annual) timescales through the acquisition and differencing of fine-resolution topographic datasets. Such data offer new opportunities to understand the process linkages between surface ablation, ice flow, and debris supply within moraine ice.

  5. Automated classifications of topography from DEMs by an unsupervised nested-means algorithm and a three-part geometric signature

    USGS Publications Warehouse

    Iwahashi, J.; Pike, R.J.

    2007-01-01

    An iterative procedure that implements the classification of continuous topography as a problem in digital image-processing automatically divides an area into categories of surface form; three taxonomic criteria-slope gradient, local convexity, and surface texture-are calculated from a square-grid digital elevation model (DEM). The sequence of programmed operations combines twofold-partitioned maps of the three variables converted to greyscale images, using the mean of each variable as the dividing threshold. To subdivide increasingly subtle topography, grid cells sloping at less than mean gradient of the input DEM are classified by designating mean values of successively lower-sloping subsets of the study area (nested means) as taxonomic thresholds, thereby increasing the number of output categories from the minimum 8 to 12 or 16. Program output is exemplified by 16 topographic types for the world at 1-km spatial resolution (SRTM30 data), the Japanese Islands at 270??m, and part of Hokkaido at 55??m. Because the procedure is unsupervised and reflects frequency distributions of the input variables rather than pre-set criteria, the resulting classes are undefined and must be calibrated empirically by subsequent analysis. Maps of the example classifications reflect physiographic regions, geological structure, and landform as well as slope materials and processes; fine-textured terrain categories tend to correlate with erosional topography or older surfaces, coarse-textured classes with areas of little dissection. In Japan the resulting classes approximate landform types mapped from airphoto analysis, while in the Americas they create map patterns resembling Hammond's terrain types or surface-form classes; SRTM30 output for the United States compares favorably with Fenneman's physical divisions. Experiments are suggested for further developing the method; the Arc/Info AML and the map of terrain classes for the world are available as online downloads. ?? 2006 Elsevier

  6. A hierarchical pyramid method for managing large-scale high-resolution drainage networks extracted from DEM

    NASA Astrophysics Data System (ADS)

    Bai, Rui; Tiejian, Li; Huang, Yuefei; Jiaye, Li; Wang, Guangqian; Yin, Dongqin

    2015-12-01

    The increasing resolution of Digital Elevation Models (DEMs) and the development of drainage network extraction algorithms make it possible to develop high-resolution drainage networks for large river basins. These vector networks contain massive numbers of river reaches with associated geographical features, including topological connections and topographical parameters. These features create challenges for efficient map display and data management. Of particular interest are the requirements of data management for multi-scale hydrological simulations using multi-resolution river networks. In this paper, a hierarchical pyramid method is proposed, which generates coarsened vector drainage networks from the originals iteratively. The method is based on the Horton-Strahler's (H-S) order schema. At each coarsening step, the river reaches with the lowest H-S order are pruned, and their related sub-basins are merged. At the same time, the topological connections and topographical parameters of each coarsened drainage network are inherited from the former level using formulas that are presented in this study. The method was applied to the original drainage networks of a watershed in the Huangfuchuan River basin extracted from a 1-m-resolution airborne LiDAR DEM and applied to the full Yangtze River basin in China, which was extracted from a 30-m-resolution ASTER GDEM. In addition, a map-display and parameter-query web service was published for the Mississippi River basin, and its data were extracted from the 30-m-resolution ASTER GDEM. The results presented in this study indicate that the developed method can effectively manage and display massive amounts of drainage network data and can facilitate multi-scale hydrological simulations.

  7. Numerical slope stability simulations of chasma walls in Valles Marineris/Mars using a distinct element method (dem).

    NASA Astrophysics Data System (ADS)

    Imre, B.

    2003-04-01

    NUMERICAL SLOPE STABILITY SIMULATIONS OF CHASMA WALLS IN VALLES MARINERIS/MARS USING A DISTINCT ELEMENT METHOD (DEM). B. Imre (1) (1) German Aerospace Center, Berlin Adlershof, bernd.imre@gmx.net The 8- to 10-km depths of Valles Marineris (VM) offer excellent views into the upper Martian crust. Layering, fracturing, lithology, stratigraphy and the content of volatiles have influenced the evolution of the Valles Marineris wallslopes. But these parameters also reflect the development of VM and its wall slopes. The scope of this work is to gain understanding in these parameters by back-simulating the development of wall slopes. For that purpose, the two dimensional Particle Flow Code PFC2D has been chosen (ITASCA, version 2.00-103). PFC2D is a distinct element code for numerical modelling of movements and interactions of assemblies of arbitrarily sized circular particles. Particles may be bonded together to represent a solid material. Movements of particles are unlimited. That is of importance because results of open systems with numerous unknown variables are non-unique and therefore highly path dependent. This DEM allows the simulation of whole development paths of VM walls what makes confirmation of the model more complete (e.g. Oreskes et al., Science 263, 1994). To reduce the number of unknown variables a proper (that means as simple as possible) field-site had to be selected. The northern wall of eastern Candor Chasma has been chosen. This wall is up to 8-km high and represents a significant outcrop of the upper Martian crust. It is quite uncomplex, well-aligned and of simple morphology. Currently the work on the model is at the stage of performing the parameter study. Results will be presented via poster by the EGS-Meeting.

  8. Geospatial approach in mapping soil erodibility using CartoDEM - A case study in hilly watershed of Lower Himalayan Range

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Gupta, Surya

    2016-09-01

    Soil erodibility is one of the most important factors used in spatial soil erosion risk assessment. Soil information derived from soil map is used to generate soil erodibility factor map. Soil maps are not available at appropriate scale. In general, soil maps at small scale are used in deriving soil erodibility map that largely generalized spatial variability and it largely ignores the spatial variability since soil map units are discrete polygons. The present study was attempted to generate soil erodibilty map using terrain indices derived from DTM and surface soil sample data. Soil variability in the hilly landscape is largely controlled by topography represented by DTM. The CartoDEM (30 m) was used to derive terrain indices such as terrain wetness index (TWI), stream power index (SPI), sediment transport index (STI) and slope parameters. A total of 95 surface soil samples were collected to compute soil erodibility factor (K) values. The K values ranged from 0.23 to 0.81 t ha-1R-1 in the watershed. Correlation analysis among K-factor and terrain parameters showed highest correlation of soil erodibilty with TWI (r 2= 0.561) followed by slope (r 2= 0.33). A multiple linear regression model was developed to derive soil erodibilty using terrain parameters. A set of 20 soil sample points were used to assess the accuracy of the model. The coefficient of determination (r 2) and RMSE were computed to be 0.76 and 0.07 t ha-1R-1 respectively. The proposed methodology is quite useful in generating soil erodibilty factor map using digital elevation model (DEM) for any hilly terrain areas. The equation/model need to be established for the particular hilly terrain under the study. The developed model was used to generate spatial soil erodibility factor (K) map of the watershed in the lower Himalayan range.

  9. An automated, open-source pipeline for mass production of digital elevation models (DEMs) from very-high-resolution commercial stereo satellite imagery

    NASA Astrophysics Data System (ADS)

    Shean, David E.; Alexandrov, Oleg; Moratto, Zachary M.; Smith, Benjamin E.; Joughin, Ian R.; Porter, Claire; Morin, Paul

    2016-06-01

    We adapted the automated, open source NASA Ames Stereo Pipeline (ASP) to generate digital elevation models (DEMs) and orthoimages from very-high-resolution (VHR) commercial imagery of the Earth. These modifications include support for rigorous and rational polynomial coefficient (RPC) sensor models, sensor geometry correction, bundle adjustment, point cloud co-registration, and significant improvements to the ASP code base. We outline a processing workflow for ∼0.5 m ground sample distance (GSD) DigitalGlobe WorldView-1 and WorldView-2 along-track stereo image data, with an overview of ASP capabilities, an evaluation of ASP correlator options, benchmark test results, and two case studies of DEM accuracy. Output DEM products are posted at ∼2 m with direct geolocation accuracy of <5.0 m CE90/LE90. An automated iterative closest-point (ICP) co-registration tool reduces absolute vertical and horizontal error to <0.5 m where appropriate ground-control data are available, with observed standard deviation of ∼0.1-0.5 m for overlapping, co-registered DEMs (n = 14, 17). While ASP can be used to process individual stereo pairs on a local workstation, the methods presented here were developed for large-scale batch processing in a high-performance computing environment. We are leveraging these resources to produce dense time series and regional mosaics for the Earth's polar regions.

  10. TanDEM-X IDEM precision and accuracy assessment based on a large assembly of differential GNSS measurements in Kruger National Park, South Africa

    NASA Astrophysics Data System (ADS)

    Baade, J.; Schmullius, C.

    2016-09-01

    High resolution Digital Elevation Models (DEM) represent fundamental data for a wide range of Earth surface process studies. Over the past years, the German TanDEM-X mission acquired data for a new, truly global Digital Elevation Model with unprecedented geometric resolution, precision and accuracy. First TanDEM Intermediate Digital Elevation Models (i.e. IDEM) with a geometric resolution from 0.4 to 3 arcsec have been made available for scientific purposes in November 2014. This includes four 1° × 1° tiles covering the Kruger National Park in South Africa. Here, we document the results of a local scale IDEM height accuracy validation exercise utilizing over 10,000 RTK-GNSS-based ground survey points from fourteen sites characterized by mainly pristine Savanna vegetation. The vertical precision of the ground checkpoints is 0.02 m (1σ). Selected precursor data sets (SRTMGL1, SRTM41, ASTER-GDEM2) are included in the analysis to facilitate the comparison. Although IDEM represents an intermediate product on the way to the new global TanDEM-X DEM, expected to be released in late 2016, it allows first insight into the properties of the forthcoming product. Remarkably, the TanDEM-X tiles include a number of auxiliary files providing detailed information pertinent to a user-based quality assessment. We present examples for the utilization of this information in the framework of a local scale study including the identification of height readings contaminated by water. Furthermore, this study provides evidence for the high precision and accuracy of IDEM height readings and the sensitivity to canopy cover. For open terrain, the 0.4 arcsec resolution edition (IDEM04) yields an average bias of 0.20 ± 0.05 m (95% confidence interval, Cl95), a RMSE = 1.03 m and an absolute vertical height error (LE90) of 1.5 [1.4, 1.7] m (Cl95). The corresponding values for the lower resolution IDEM editions are about the same and provide evidence for the high quality of the IDEM products

  11. Jakobshavn Isbrae, Greenland: DEMs, orthophotos, surface velocities, and ice loss derived from photogrammetric re-analysis of July 1985 repeat aerial photography

    NASA Astrophysics Data System (ADS)

    Motyka, R.; Fahnestock, M.; Howat, I.; Truffer, M.; Brecher, H.; Luethi, M.

    2008-12-01

    Jakobshavn Isbrae drains about 7 % of the Greenland Ice Sheet and is the ice sheet's largest outlet glacier. Two sets of high elevation (~13,500 m), high resolution (2 m) aerial photographs of Jakobshavn Isbrae were obtained about two weeks apart during July 1985 (Fastook et al, 1995). These historic photo sets have become increasingly important for documenting and understanding the dynamic state of this outlet stream prior to the rapid retreat and massive ice loss that began in 1998 and continues today. The original photogrammetric analysis of this imagery is summarized in Fastook et al. (1995). They derived a coarse DEM (3 km grid spacing) covering an area of approximately 100 km x 100 km by interpolating several hundred positions determined manually from block-aerial triangulation. We have re-analyzed these photos sets using digital photogrammetry (BAE Socet Set©) and significantly improved DEM quality and resolution (20, 50, and 100 m grids). The DEMs were in turn used to produce high quality orthophoto mosaics. Comparing our 1985 DEM to a DEM we derived from May 2006 NASA ATM measurements showed a total ice volume loss of ~ 105 km3 over the lower drainage area; almost all of this loss has occurred since 1997. Ice stream surface velocities derived from the 1985 orthomosaics showed speeds of 20 m/d on the floating tongue, diminishing to 5 m/d at 50 km further upstream. Velocities have since nearly doubled along the ice stream during its current retreat. Fastook, J.L., H.H. Brecher, and T.J. Hughes, 1995. J.of Glaciol. 11 (137), 161-173.

  12. Characterization of arginine kinase, anovel allergen of dermatophagoides farinae (Der f 20)

    PubMed Central

    Xing, Peng; Yu, Haiqiong; Li, Meng; Xiao, Xiaojun; Jiang, Congli; Mo, Lihua; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2015-01-01

    Objective: To characterize a novel allergen, the Dermatophagoides farinae-derived arginine kinase (Der f 20). Methods: The protein of Der f 20 was synthesized by genetic engineering approaches. The allergenicity of Der f 20 was tested by enzyme-linked immunosorbent assay and an airway allergy mouse model. Results: The Der f 20 gene was cloned andpresented in the Gene Bank with an accession number of AAP57094. The Der f 20 is an arginine kinase (AK), whichshowed a close relationship with D. pteronyssinus AK and Aleuroglyphusovatus AK. Western-blot and ELISA studies showed the IgE binding capacity of Der f 20 was 66.7% in the sera from 6 dust mite allergic patients. Immune inhibition assayresults showed the IgE cross-reactivity between Der f 20 and DME (Dust mite extract). Positive responses to Der f 20 were 41.2% as shown by skin prick tests in 17 DME-allergic patients. In vitro experimental results showed that Der f 20 induced Th2 cell differentiation and the expression of T cell Ig mucin domain molecule-4 (TIM4) in DCs. Conclusions; The Der f 20 protein is a novel subtype of thedust mite allergen. PMID:26885278

  13. Expression, purification and characterization of Der f 27, a new allergen from dermatophagoides farinae.

    PubMed

    Lin, Jianli; Li, Meng; Liu, Yulin; Jiang, Congli; Wu, Yulan; Wang, Yuanyuan; Gao, Anjian; Liu, Zhigang; Yang, Pingchang; Liu, Xiaoyu

    2015-01-01

    The house dust mite (HDM), Dermatophagoidesfarinae (D. farina), is one of the most important indoor allergen sources and a major elicitor of allergic asthma; itscharacterization is important in the diagnosis and immunotherapy of mite allergen-relevant diseases. This study aims to characterize a novel allergen, the D. farinae-derived serpin (Der f 27). In this study, the total RNA of D. farinae was extracted, and the Der f 27 gene was cloned and expressed. The allergenicity of recombinant Der f 27 protein was determined by enzyme-linked immunosorbent assay, and Western-blotting with the sera of asthma patients, and skin prick test (SPT) in allergic human subjects. A r-Der f 27 allergic asthma mouse model was established. The cloned Der f 27 gene has been presented at the Gene Bank with an accession number of KM009995. The IgE levels of r-Der f 27 in the serum from r-Der f 27 SPT positive allergic patients were 3 folds more than healthy subjects. The Der f 27 SPT positive ratewas 42.1% in 19 DM-SPT positive patients. Airway hyperresponsiveness, serum specific IgE, and levels of interleukin-4 in the spleen cell culture supernatant were significantly increased in allergic asthma mice sensitized to r-Der f 27. In conclusion, Der f 27 is a new subtype of house mite allergen.

  14. Generalized van der Waals density functional theory for nonuniform polymers

    SciTech Connect

    Patra, Chandra N.; Yethiraj, Arun

    2000-01-15

    A density functional theory is presented for the effect of attractions on the structure of polymers at surfaces. The theory treats the ideal gas functional exactly, and uses a weighted density approximation for the hard chain contribution to the excess free energy functional. The attractive interactions are treated using a van der Waals approximation. The theory is in good agreement with computer simulations for the density profiles at surfaces for a wide range of densities and temperatures, except for low polymer densities at low temperatures where it overestimates the depletion of chains from the surface. This deficiency is attributed to the neglect of liquid state correlations in the van der Waals term of the free energy functional. (c) 2000 American Institute of Physics.

  15. Photovoltaic effect in an electrically tunable van der Waals heterojunction.

    PubMed

    Furchi, Marco M; Pospischil, Andreas; Libisch, Florian; Burgdörfer, Joachim; Mueller, Thomas

    2014-08-13

    Semiconductor heterostructures form the cornerstone of many electronic and optoelectronic devices and are traditionally fabricated using epitaxial growth techniques. More recently, heterostructures have also been obtained by vertical stacking of two-dimensional crystals, such as graphene and related two-dimensional materials. These layered designer materials are held together by van der Waals forces and contain atomically sharp interfaces. Here, we report on a type-II van der Waals heterojunction made of molybdenum disulfide and tungsten diselenide monolayers. The junction is electrically tunable, and under appropriate gate bias an atomically thin diode is realized. Upon optical illumination, charge transfer occurs across the planar interface and the device exhibits a photovoltaic effect. Advances in large-scale production of two-dimensional crystals could thus lead to a new photovoltaic solar technology.

  16. van der Waals explosion of cold Rydberg clusters

    NASA Astrophysics Data System (ADS)

    Faoro, R.; Simonelli, C.; Archimi, M.; Masella, G.; Valado, M. M.; Arimondo, E.; Mannella, R.; Ciampini, D.; Morsch, O.

    2016-03-01

    We report on the direct measurement in real space of the effect of the van der Waals forces between individual Rydberg atoms on their external degrees of freedom. Clusters of Rydberg atoms with interparticle distances of around 5 μ m are created by first generating a small number of seed excitations in a magneto-optical trap, followed by off-resonant excitation that leads to a chain of facilitated excitation events. After a variable expansion time the Rydberg atoms are field ionized, and from the arrival time distributions the size of the Rydberg cluster after expansion is calculated. Our experimental results agree well with a numerical simulation of the van der Waals explosion.

  17. Charge Transfer Excitons at van der Waals Interfaces.

    PubMed

    Zhu, Xiaoyang; Monahan, Nicholas R; Gong, Zizhou; Zhu, Haiming; Williams, Kristopher W; Nelson, Cory A

    2015-07-01

    The van der Waals interfaces of molecular donor/acceptor or graphene-like two-dimensional (2D) semiconductors are central to concepts and emerging technologies of light-electricity interconversion. Examples include, among others, solar cells, photodetectors, and light emitting diodes. A salient feature in both types of van der Waals interfaces is the poorly screened Coulomb potential that can give rise to bound electron-hole pairs across the interface, i.e., charge transfer (CT) or interlayer excitons. Here we address common features of CT excitons at both types of interfaces. We emphasize the competition between localization and delocalization in ensuring efficient charge separation. At the molecular donor/acceptor interface, electronic delocalization in real space can dictate charge carrier separation. In contrast, at the 2D semiconductor heterojunction, delocalization in momentum space due to strong exciton binding may assist in parallel momentum conservation in CT exciton formation. PMID:26001297

  18. Photovoltaic Effect in an Electrically Tunable van der Waals Heterojunction

    PubMed Central

    2014-01-01

    Semiconductor heterostructures form the cornerstone of many electronic and optoelectronic devices and are traditionally fabricated using epitaxial growth techniques. More recently, heterostructures have also been obtained by vertical stacking of two-dimensional crystals, such as graphene and related two-dimensional materials. These layered designer materials are held together by van der Waals forces and contain atomically sharp interfaces. Here, we report on a type-II van der Waals heterojunction made of molybdenum disulfide and tungsten diselenide monolayers. The junction is electrically tunable, and under appropriate gate bias an atomically thin diode is realized. Upon optical illumination, charge transfer occurs across the planar interface and the device exhibits a photovoltaic effect. Advances in large-scale production of two-dimensional crystals could thus lead to a new photovoltaic solar technology. PMID:25057817

  19. Van der Waals interaction-tuned heat transfer in nanostructures.

    PubMed

    Sun, Tao; Wang, Jianxiang; Kang, Wei

    2013-01-01

    Interfaces usually impede heat transfer in heterogeneous structures. Recent experiments show that van der Waals (vdW) interactions can significantly enhance thermal conductivity parallel to the interface of a bundle of nanoribbons compared to a single layer of freestanding nanoribbon. In this paper, by simulating heat transfer in nanostructures based on a model of nonlinear one-dimensional lattices interacting via van der Waals interactions, we show that the vdW interface interaction can adjust the thermal conductivity parallel to the interface. The efficiency of the adjustment depends on the intensity of interactions and temperature. The nonlinear dependence of the conductivity on the intensity of interactions agrees well with experimental results for carbon nanotube bundles, multi-walled carbon nanotubes, multi-layer graphene, and nanoribbons.

  20. Quantum field theory of van der Waals friction

    SciTech Connect

    Volokitin, A. I.; Persson, B. N. J.

    2006-11-15

    van der Waals friction between two semi-infinite solids, and between a small neutral particle and semi-infinite solid is studied using thermal quantum field theory in the Matsubara formulation. We show that the friction to linear order in the sliding velocity can be obtained from the equilibrium Green functions and that our treatment can be extended for bodies with complex geometry. The calculated friction agrees with the friction obtained using a dynamical modification of the Lifshitz theory, which is based on the fluctuation-dissipation theorem. We show that it should be possible to measure the van der Waals friction in noncontact friction experiment using state-of-the-art equipment.

  1. Spin-Flavor van der Waals Forces and NN interaction

    SciTech Connect

    Alvaro Calle Cordon, Enrique Ruiz Arriola

    2011-12-01

    A major goal in Nuclear Physics is the derivation of the Nucleon-Nucleon (NN) interaction from Quantum Chromodynamics (QCD). In QCD the fundamental degrees of freedom are colored quarks and gluons which are confined to form colorless strongly interacting hadrons. Because of this the resulting nuclear forces at sufficiently large distances correspond to spin-flavor excitations, very much like the dipole excitations generating the van der Waals (vdW) forces acting between atoms. We study the Nucleon-Nucleon interaction in the Born-Oppenheimer approximation at second order in perturbation theory including the Delta resonance as an intermediate state. The potential resembles strongly chiral potentials computed either via soliton models or chiral perturbation theory and has a van der Waals like singularity at short distances which is handled by means of renormalization techniques. Results for the deuteron are discussed.

  2. Persistent hysteresis in graphene-mica van der Waals heterostructures.

    PubMed

    Mohrmann, Jens; Watanabe, Kenji; Taniguchi, Takashi; Danneau, Romain

    2015-01-01

    We report the study of electronic transport in graphene-mica van der Waals heterostructures. We have designed various graphene field-effect devices in which mica is utilized as a substrate and/or gate dielectric. When mica is used as a gate dielectric we observe a very strong positive gate voltage hysteresis of the resistance, which persists in samples that were prepared in a controlled atmosphere down to even millikelvin temperatures. In a double-gated mica-graphene-hBN van der Waals heterostructure, we found that while a strong hysteresis occurred when mica was used as a substrate/gate dielectric, the same graphene sheet on mica substrate no longer showed hysteresis when the charge carrier density was tuned through a second gate with the hBN dielectric. While this hysteretic behavior could be useful for memory devices, our findings confirm that the environment during sample preparation has to be controlled strictly.

  3. Isolated lower lip fistulas in Van der Woude syndrome.

    PubMed

    Etöz, Osman A; Etöz, Abdullah

    2009-09-01

    Van der Woude syndrome (VWS) is a dominantly inherited disease of orofacial region. Characteristic features of this syndrome are bilateral lower lip sinuses along with cleft lip or palate deformity. However, isolated lower lip pits in VWS without any cleft syndrome is uncommon. Lip pits in VWS are usually asymptomatic; however, patients may complain of watery drainage and/or infection. In this report, asymptomatic isolated lower lip sinuses without any cleft syndrome in a patient and his father are presented. PMID:19816310

  4. Van der Woude syndrome with an unusual intraoral finding.

    PubMed

    Sarode, Gargi S; Desai, Rajiv S; Sarode, Sachin C; Kulkarni, Meena A

    2011-01-01

    Orofacial manifestations of Van der Woude syndrome (VWS) include cleft lip or palate, lower lip pits, hypodontia, hypernasal voice, cleft or bifid uvula, syngnathia, narrow high arched palate, and ankyloglossia. Extraoral manifestations include limb anomalies, popliteal webs, accessory nipples, congenital heart defects, and Hirschsprung disease. We report an interesting case of VWS with characteristic orofacial features along with an unusual additional finding of fusion of primary mandibular left lateral incisor and canine in a 7-year-old boy. PMID:21525698

  5. Van der Waals interactions: accuracy of pair potential approximations.

    PubMed

    Cole, Milton W; Kim, Hye-Young; Liebrecht, Michael

    2012-11-21

    Van der Waals interactions between single atoms and solids are discussed for the regime of large separation. A commonly employed approximation is to evaluate this interaction as a sum of two-body interactions between the adatom and the constituent atoms of the solid. The resulting potentials are here compared with known results in various geometries. Analogous comparisons are made for diatomic molecules near either single atoms or semi-infinite surfaces and for triatomic molecules' interactions with single atoms. PMID:23181315

  6. Twilight of the gods: John Henry Mackay's Der Unschuldige.

    PubMed

    Kennedy, H

    1993-01-01

    The writings of the Scotch-German John Henry Mackay are important for the early cultural history of the modern gay movement. This article recalls this unjustly neglected anarchist writer and advocate of man/boy love by tracing his biography and pointing out his contacts with others in the movement. His late novella Der Unschuldige is analyzed to show that Mackay has encoded homosexuality there in a unique and individual way. PMID:8113599

  7. Laboratory tests of IEC DER object models for grid applications.

    SciTech Connect

    Blevins, John D.; Menicucci, David F.; Byrd, Thomas, Jr.; Gonzalez, Sigifredo; Ginn, Jerry W.; Ortiz-Moyet, Juan

    2007-02-01

    This report describes a Cooperative Research and Development Agreement (CRADA) between Salt River Project Agricultural Improvement and Power District (SRP) and Sandia National Laboratories to jointly develop advanced methods of controlling distributed energy resources (DERs) that may be located within SRP distribution systems. The controls must provide a standardized interface to allow plug-and-play capability and should allow utilities to take advantage of advanced capabilities of DERs to provide a value beyond offsetting load power. To do this, Sandia and SRP field-tested the IEC 61850-7-420 DER object model (OM) in a grid environment, with the goal of validating whether the model is robust enough to be used in common utility applications. The diesel generator OM tested was successfully used to accomplish basic genset control and monitoring. However, as presently constituted it does not enable plug-and-play functionality. Suggestions are made of aspects of the standard that need further development and testing. These problems are far from insurmountable and do not imply anything fundamentally unsound or unworkable in the standard.

  8. Messen, Kalibrieren, Eichen in der Radiologie: Prinzipien und Praxis

    NASA Astrophysics Data System (ADS)

    Wagner, Siegfried R.

    Nach einleitender Erläuterung der unterschiedlichen Meßbedingungen in der Strahlentherapie und im Strahlenschutz werden die metrologischen Probleme am Beispiel der Größenkategorie Äquivalentdosis diskutiert. Als spezielle Größen werden effektive Äquivalentdosis und Umgebungs-Äquivalentdosis eingeführt. Es wird gezeigt, wie richtiges Messen durch ein konsistentes System von Bauartanforderungen an Meßgeräte, durch Kalibrieren und durch Eichen gewährleistet werden kann. Die Bedeutung von Meßunsicherheiten und Fehlergrenzen wird erläutert und ihre Auswirkung auf die Interpretation von Meßergebnissen behandelt.Translated AbstractMeasurements, Calibration, Verification in Radiology: Principles and PracticeThe different measuring conditions in radiotherapy and in radiation protection are discussed in the introduction. Then, the metrological problems are discussed exemplarily with the dose equivalent as a category of quantity. Effective dose equivalent and ambient dose equivalent are introduced as special quantities. It is demonstrated, how correct measurements can be secured by a consistent system of instrument pattern requirements, by calibration and verification. The importance of uncertainties of measurements and of error limits is illustrated and their influence on the interpretation of the results of measurements is treated.

  9. Nonadiabatic Van der Pol oscillations in molecular transport

    NASA Astrophysics Data System (ADS)

    Kartsev, Alexey; Verdozzi, Claudio; Stefanucci, Gianluca

    2014-01-01

    The force exerted by the electrons on the nuclei of a current-carrying molecular junction can be manipulated to engineer nanoscale mechanical systems. In the adiabatic regime a peculiarity of these forces is negative friction, responsible for Van der Pol oscillations of the nuclear coordinates. In this work we study the robustness of the Van der Pol oscillations against high-frequency sources. For this purpose we go beyond the adiabatic approximation and perform full Ehrenfest dynamics simulations. The numerical scheme implements a mixed quantum-classical algorithm for open systems and is capable to deal with arbitrary time-dependent driving fields. We find that the Van der Pol oscillations are extremely stable. The nonadiabatic electron dynamics distorts the trajectory in the momentum-coordinate phase space but preserves the limit cycles in an average sense. We further show that high-frequency fields change both the oscillation amplitudes and the average nuclear positions. By switching the fields off at different times one obtains cycles of different amplitudes which attain the limit cycle only after considerably long times.

  10. Identifying hydrologically sensitive areas using LiDAR DEMs to mitigate critical source areas of diffuse pollution: development and application

    NASA Astrophysics Data System (ADS)

    Thomas, Ian; Jordan, Phil; Mellander, Per-Erik; Fenton, Owen; Shine, Oliver; hUallacháin, Daire Ó.; Creamer, Rachel; McDonald, Noeleen; Dunlop, Paul; Murphy, Paul

    2016-04-01

    Identifying critical source areas (CSAs) of diffuse pollution in agricultural catchments requires the accurate identification of hydrologically sensitive areas (HSAs) at highest propensity for generating surface runoff and transporting pollutants such as phosphorus (P). A new GIS-based HSA Index is presented that identifies HSAs at the sub-field scale. It uses a soil topographic index (STI) and accounts for the hydrological disconnection of overland flow via topographic impediment from flow sinks such as hedgerows and depressions. High resolution (0.25-2 m) LiDAR Digital Elevation Models (DEMs) are utilised to capture these microtopographic controls on flow pathways and hydrological connectivity. The HSA Index was applied to four agricultural catchments (~7.5-12 km2) with contrasting topography and soil types. Catchment HSA sizes were estimated using high resolution rainfall-quickflow measurements during saturated winter storm events in 2009-2014, and mapped using the HSA Index. HSA sizes ranged from 1.6-3.4% of the catchment area during median storm events and 2.9-8.5% during upper quartile events depending on whether well or poorly drained soils dominated, which validated HSA Index value distributions. Total flow sink volume capacities ranged from 8,298-59,584 m3 and caused 8.5-24.2% of overland-flow-generating-areas and 16.8-33.4% of catchment areas to become hydrologically disconnected from the open drainage channel network. HSA maps identified 'delivery points' along surface runoff pathways where transported pollutants such as P are delivered to the open drainage network. Using these as proposed locations for targeting mitigation measures such as riparian buffer strips (RBS) reduced costs compared to blanket implementation within an example agri-environment scheme by 66% and 91% over 1 and 5 years respectively, which included LiDAR DEM acquisition costs. Considering that HSAs are often the dominant P CSA factor in agricultural catchments and can override

  11. Auf dem Weg zu einem neuen Weltcurriculum? Zum Grundbildungskonzept von PISA und der Aufgabenzuweisung an die Schule (Towards a World Curriculum? -- The Concept of Basic Education (Literacy) underlying PISA and the tasks allocated to Schooling).

    ERIC Educational Resources Information Center

    Fuchs, Hans-Werner

    2003-01-01

    Recognizes that the debate on the Program for International Student Assessment 2000 (PISA) has been dominated by comparisons of the ranks achieved and by the question of the consequences to be drawn from the results. Discusses the educational concept forming the basis for the investigation and aims of PISA. (CAJ)

  12. Fine Resolution Tree Height Estimation from Lidar Data and Its Application in SRTM DEM Correction across Forests of Sierra Nevada, California, USA

    NASA Astrophysics Data System (ADS)

    Su, Y.; Guo, Q.; Ma, Q.; Li, W.

    2015-12-01

    Sierra Nevada (SN) is a mountain range located in the northeastern California, USA, covering an area of 63,100 km2. As one of the most diverse temperate conifer forests on the Earth, forests of SN serve a series of ecosystem functions and are valuable natural heritages for the region and even the country. The still existed gap of accurate fine-resolution tree height estimation has lagged ecological, hydrological and forestry studies within the region. Moreover, the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM), as one of the most frequently used land surface elevation product in the region, has been proved systematically higher than actual land surface in vegetated mountain areas due to the absorption and reflection effects of canopy on the SRTM radar signal. An accurate fine resolution tree height product across the region is urgently needed for developing models to correct SRTM DEM. In this study, we firstly developed a method to estimate SN tree height distribution (defined by Lorey's height) through the combination of airborne lidar data, spaceborne lidar data, optical imagery, climate surfaces, and field measurements. Over 5 470 km2airborne lidar data and 1 000 plot measurements were collected across the SN to address this mission. Our method involved three main steps: 1) estimate tree heights within airborne lidar footprints using step-wise regression; 2) link the airborne lidar derived tree height to spaceborne lidar data and compute tree heights at spaceborne lidar footprints; 3) extrapolate tree height estimation from spaceborne lidar footprints to the whole region using Random Forest. The obtained SN tree height product showed good correspondence with independent field plot measurements. The coefficient of determination is higher than 0.65, and the root-mean-square error is around 5 m. With the obtained tree height product, we further explored the possibility of correcting SRTM DEM. The results showed that the obtained tree height

  13. Muldrow Glacier and the effect of debris cover on geodetic volume change estimates from DEM and LiDAR elevation measurements

    NASA Astrophysics Data System (ADS)

    Murphy, N.; Larsen, C. F.; Herreid, S. J.

    2011-12-01

    Since 1993, the University of Alaska (UAF) Glaciers Group has monitored glacier volume changes across Alaska and northern Canada using light aircraft laser altimetry surveys. These surveys are currently part of NASA's Operation IceBridge. As part of the ongoing study, we examine the volume and topography changes in Muldrow Glacier, located in the Central Alaska Range, from 1952 through 2010 using a combination of DEMs, centerline laser altimetry (1994, 2001, and 2008) and LiDAR data (2010), and debris cover maps. Current data show that the volume loss rate for Muldrow Glacier has increased significantly during this period from a mean rate of ~-0.02 km3/yr from 1952 to 1976 to a mean rate of ~-0.19 km3/yr from 2008 to 2010. Flight path laser altimetry data are used to track elevations when no DEM data are available. Laser altimetry and LiDAR measure elevation changes along the centerline of the glacier with an accuracy of ±30cm and are then extrapolated over the entire glacier using the best available DEM. Debris cover on glaciers often has significant and spatially variable effects on the melt rate of glaciers. Due to the spatial variability of debris cover on a glacier, it can represent a source of uncertainty when extrapolating the centerline elevation data to the entire glacier. In order to improve the extrapolation of the centerline elevation data for all glaciers currently being surveyed by UAF, we concentrate on the elevation changes of and spatial distribution of rock debris on Muldrow Glacier. We compare elevation changes based on DEMs from 1952 (from the National Elevation Database), 1976 (a digitized version of Bradford Washburn's topographic map of Muldrow), and 2006 (from AeroMetric, Inc.). We use debris field maps acquired during the mid-1970s and ~2006 in combination with the DEMs to investigate the insulation effects of debris on differential melt rates across the glacier. By also comparing the DEM and debris cover data with data from the aircraft

  14. Developing sub 5-m LiDAR DEMs for forested sections of the Alpine and Hope faults, South Island, New Zealand: Implications for structural interpretations

    NASA Astrophysics Data System (ADS)

    Langridge, R. M.; Ries, W. F.; Farrier, T.; Barth, N. C.; Khajavi, N.; De Pascale, G. P.

    2014-07-01

    Kilometre-wide airborne light detection and ranging (LiDAR) surveys were collected along portions of the Alpine and Hope faults in New Zealand to assess the potential for generating sub 5-m bare earth digital elevation models (DEMs) from ground return data in areas of dense rainforest (bush) cover as an aid to mapping these faults. The 34-km long Franz-Whataroa LiDAR survey was flown along the densely-vegetated central-most portion of the transpressive Alpine Fault. Six closely spaced flight lines (200 m apart) yielded survey coverage with double overlap of swath collection, which was considered necessary due to the low density of ground returns (0.16 m-2 or a point every 6 m2) under mature West Coast podocarp-broadleaf rainforest. This average point spacing (˜2.5 m) allowed for the generation of a robust, high quality 3-m bare earth DEM. The DEM confirmed the zigzagged form of the surface trace of the Alpine Fault in this area, originally recognised by Norris and Cooper (1995, 1997) and highlights that the surface strike variations are more variant than previously mapped. The 29-km long Hurunui-Hope LiDAR survey was flown east of the Main Divide of the Southern Alps along the dextral-slip Hope Fault, where the terrain is characterised by lower rainfall and more open beech forest. Flight line spacings of ˜275 m were used to generate a DEM from the ground return data. The average ground return values under beech forest were 0.27 m-2 and yielded an estimated cell size suitable for a 2-m DEM. In both cases the LiDAR revealed unprecedented views of the surface geomorphology of these active faults. Lessons learned from our survey methodologies can be employed to plan cost-effective, high-gain airborne surveys to yield bare earth DEMs underneath vegetated terrain and multi-storeyed canopies from densely forested environments across New Zealand and worldwide.

  15. van der Waals coefficients for systems with ultracold polar alkali-metal molecules

    NASA Astrophysics Data System (ADS)

    Żuchowski, P. S.; Kosicki, M.; Kodrycka, M.; Soldán, P.

    2013-02-01

    A systematic study of the leading isotropic van der Waals coefficients for the alkali-metal atom+molecule and molecule+molecule systems is presented. Dipole moments and static and dynamic dipole polarizabilities are calculated employing high-level quantum chemistry calculations. The dispersion, induction, and rotational parts of the isotropic van der Waals coefficient are evaluated. The known van der Waals coefficients are then used to derive characteristics essential for simple models of the collisions involving the corresponding ultracold polar molecules.

  16. Application of Diffusion Monte Carlo to Materials Dominated by van der Waals Interactions

    SciTech Connect

    Benali, Anouar; Shulenburger, Luke; Romero, Nichols A.; Kim, Jeongnim; von Lilienfeld, O. Anatole

    2014-06-12

    Van der Waals forces are notoriously difficult to account for from first principles. We perform extensive calculation to assess the usefulness and validity of diffusion quantum Monte Carlo when applied to van der Waals forces. We present results for noble gas solids and clusters - archetypical van der Waals dominated assemblies, as well as a relevant pi-pi stacking supramolecular complex: DNA + intercalating anti-cancer drug Ellipticine.

  17. DEM analyses of the whole failure process of shallow foundation in plate load test on dense sand

    NASA Astrophysics Data System (ADS)

    Li, L.; Jiang, M. J.; Li, T.; Chen, S. L.

    2015-09-01

    Shallow foundations are widely used in civil engineering practice, but the instability mechanism is still unclear yet. Previously, the Finite Element Method (FEM) was commonly used to analyze the failure process of shallow foundations, but it meets difficulty in properly simulating the whole failure process of shallow foundation on the strain-softening material. Hence, the Discrete Element Method (DEM) is employed in this paper to study the instability mechanism of the shallow foundation via numerical plate load test with focus on the microscopic features evolution during vertical loading. In the simulation, an amplified gravity was applied to a dense granular ground to reproduce a gravity stress state at a large scale. Then, a plate was put on the granular ground to simulate the plate load test. Deformation pattern, particle velocity and distribution of void ratio in the ground were examined to illustrate the microscopic features in the whole failure process of the granular ground. The results show that: 1) There are a marked peak value and a settlement softening branch in the stress-settlement relationship. 2) The grids close to the edge of the plate are peculiarly extended and twisted. 3) Four particle motion patterns were observed in the velocity fields and the percentage of each motion pattern changes during loading. 4) The void ratio field varies during loading, and the distinguishing interface tends to be similar to Terzaghi's shear failure surface.

  18. DEMS study of gas evolution at thick graphite electrodes for lithium-ion batteries: the effect of γ-butyrolactone

    NASA Astrophysics Data System (ADS)

    Lanz, Martin; Novák, Petr

    Differential electrochemical mass spectrometry (DEMS) was used to study the reductive decomposition of an electrolyte based on ethylene carbonate/dimethyl carbonate (EC/DMC), as well as the formation of a solid electrolyte interphase (SEI) in this electrolyte, at thick (75-100 μm) porous graphite composite electrodes. A number of graphite electrodes differing in their electrochemical lithium intercalation properties were investigated in potential-sweep experiments. They proved to be similar with respect to the evolution of ethylene and hydrogen gas during the first two charge/discharge cycles. Due to an incomplete coulombic conversion, a high irreversible capacity, as well as slow diffusion kinetics and an enhanced ohmic resistance of the electrodes, SEI formation on these thick electrodes was not yet complete after the first charge/discharge cycle. Undesired gas evolution can be reduced by adding γ-butyrolactone (GBL) as an electrolyte co-solvent. The amount of ethylene and hydrogen gas evolved decreases with increasing percentages of GBL in an EC/DMC electrolyte, indicating that the SEI layer is built up from GBL rather than from EC decomposition products.

  19. Integrated Optical and SAR Imagery with DEM to Quantify Glacier Water Storage Change in Upper Mekong River Basin

    NASA Astrophysics Data System (ADS)

    Liu, G. T.; Chen, J. B.; Le, T. S.; Chang, C. P.; Shum, C. K.; Tseng, K. H.

    2015-12-01

    In the past few decades, regional increase in air temperature has accelerated the ice melting in polar, sub-polar, and major land glacial areas. The glaciers in Tibetan Plateau, the largest glaciers outside Polar Regions and the sources of several trans-boundary major rivers, are now showing aggravated terminus retreat and thinning. The variation of freshwater availability is crucial for the economic development in Mainland Southeast Asia, especially in hydroelectric generation and agriculture irrigation. These rives, including the Mekong River, is also subject to upstream-downstream conflict and transboundary issues. In this study, we propose to estimate the remaining glacier water storage in Mekong River basin, and further analyze the impact of glacier retreat on these dams/reservoirs for the next decade. By calculating the Modified Normalized Difference Water Index (MNDWI), the water surface area (WSA) can thus be extracted from optical satellite images. On the other hand, the ice surface area (ISA) can be derived from the Polarimetric Synthetic Aperture Radar (POLSAR) images. With different polarization states of electromagnetic wave reflected by earth surface, POLSAR image can effectively identify glacier/ice from snow. Combined WSA and ISA information with digital elevation model (DEM), the change of freshwater storage in glaciers can be estimated. In the end, the influence on dams/reservoirs in the Mekong River caused by glacier retreat can be forecasted. The result can also be applied to hydrology, water allocation, and economy/agriculture policy determination.

  20. Bewertung von Fahrerassistenzsystemen mittels der Vehicle in the Loop-Simulation

    NASA Astrophysics Data System (ADS)

    Bock, Thomas

    Mit der Vehicle in the Loop-Simulation hat Audi eine Test- und Simulationsumgebung für Fahrerassistenzsysteme entwickelt, welche die Vorzüge eines realen Versuchsfahrzeugs mit der Sicherheit und Reproduzierbarkeit von Fahrsimulatoren kombiniert. Virtueller Fremdverkehr, Straßenbegrenzungen oder sonstige simulierte Gegenstände werden durch ein "Optical see through Head Mounted Display“ während der Fahrt realitätsnah und kontaktanalog für den Fahrer eingeblendet. Besonders bei der Erprobung aktiver Fahrerassistenzsysteme eröffnen sich durch das Konzept des virtuellen Fremdverkehrs im realen Versuchsfahrzeug neue Möglichkeiten.

  1. Abenteuer Weltall.

    NASA Astrophysics Data System (ADS)

    Kippenhahn, R.

    Contents: 1. Die Rätsel der Venus. 2. Der rote Planet. 3. Aus dem Logbuch der Voyager-Sonden. 4. Das Schicksal von Sonne und Sternen. 5. Der Friedhof der Sterne. 6. Sterne, die man hören kann. 7. Röntgensterne und Schwarze Löcher. 8. Im Reich der Galaxien. 9. Radiosender des Himmels. 10. Fremdes Leben in der Milchstraße? 11. Alarm aus dem Weltall. 12. Quasare. 13. Der Anfang der Welt.

  2. The role of method of production and resolution of the DEM on slope-units delineation for landslide susceptibility assessment - Ubaye Valley, French Alps case study

    NASA Astrophysics Data System (ADS)

    Schlögel, Romy; Marchesini, Ivan; Alvioli, Massimiliano; Reichenbach, Paola; Rossi, Mauro; Malet, Jean-Philippe

    2016-04-01

    Landslide susceptibility assessment forms the basis of any hazard mapping, which is one of the essential parts of quantitative risk mapping. For the same study area, different susceptibility maps can be achieved depending on the type of susceptibility mapping methods, mapping unit, and scale. In the Ubaye Valley (South French Alps), we investigate the effect of resolution and method of production of the DEM to delineate slope units for landslide susceptibility mapping method. Slope units delineation has been processed using multiple combinations of circular variance and minimum area size values, which are the input parameters for a new software for terrain partitioning. We rely on this method taking into account homogeneity of aspect direction inside each unit and inhomogeneity between different units. We computed slope units delineation for 5, 10 and 25 meters resolution DEM, and investigate statistical distributions of morphometric variables within the different polygons. Then, for each different slope units partitioning, we calibrated a landslide susceptibility model, considering landslide bodies and scarps as a dependent variable (binary response). This work aims to analyse the role of DEM resolution on slope-units delineation for landslide susceptibility assessment. Area Under the Curve of the Receiver Operating Characteristic is investigated for the susceptibility model calculations. In addition, we analysed further the performance of the Logistic Regression Model by looking at the percentage of significant variable in the statistical analyses. Results show that smaller slope units have a better chance of containing a smaller number of thematic and morphometric variables, allowing for an easier classification. Reliability of the models according to the DEM resolution considered as well as scarp area and landslides bodies presence/absence as dependent variable are discussed.

  3. An efficient and comprehensive method for drainage network extraction from DEM with billions of pixels using a size-balanced binary search tree

    NASA Astrophysics Data System (ADS)

    Bai, Rui; Li, Tiejian; Huang, Yuefei; Li, Jiaye; Wang, Guangqian

    2015-06-01

    With the increasing resolution of digital elevation models (DEMs), computational efficiency problems have been encountered when extracting the drainage network of a large river basin at billion-pixel scales. The efficiency of the most time-consuming depression-filling pretreatment has been improved by using the O(NlogN) complexity least-cost path search method, but the complete extraction steps following this method have not been proposed and tested. In this paper, an improved O(NlogN) algorithm was proposed by introducing a size-balanced binary search tree (BST) to improve the efficiency of the depression-filling pretreatment further. The following extraction steps, including the flow direction determination and the upslope area accumulation, were also redesigned to benefit from this improvement. Therefore, an efficient and comprehensive method was developed. The method was tested to extract drainage networks of 31 river basins with areas greater than 500,000 km2 from the 30-m-resolution ASTER GDEM and two sub-basins with areas of approximately 1000 km2 from the 1-m-resolution airborne LiDAR DEM. Complete drainage networks with both vector features and topographic parameters were obtained with time consumptions in O(NlogN) complexity. The results indicate that the developed method can be used to extract entire drainage networks from DEMs with billions of pixels with high efficiency.

  4. Leveraging the power of multi-core platforms for large-scale geospatial data processing: Exemplified by generating DEM from massive LiDAR point clouds

    NASA Astrophysics Data System (ADS)

    Guan, Xuefeng; Wu, Huayi

    2010-10-01

    In recent years improvements in spatial data acquisition technologies, such as LiDAR, resulted in an explosive increase in the volume of spatial data, presenting unprecedented challenges for computation capacity. At the same time, the kernel of computing platforms the CPU, also evolved from a single-core to multi-core architecture. This radical change significantly affected existing data processing algorithms. Exemplified by the problem of generating DEM from massive air-borne LiDAR point clouds, this paper studies how to leverage the power of multi-core platforms for large-scale geospatial data processing and demonstrates how multi-core technologies can improve performance. Pipelining is adopted to exploit the thread level parallelism of multi-core platforms. First, raw point clouds are partitioned into overlapped blocks. Second, these discrete blocks are interpolated concurrently on parallel pipelines. On the interpolation run, intermediate results are sorted and finally merged into an integrated DEM. This parallelization demonstrates the great potential of multi-core platforms with high data throughput and low memory footprint. This approach achieves excellent performance speedup with greatly reduced processing time. For example, on a 2.0 GHz Quad-Core Intel Xeon platform, the proposed parallel approach can process approximately one billion LiDAR points (16.4 GB) in about 12 min and produces a 27,500×30,500 raster DEM, using less than 800 MB main memory.

  5. Analyse der Plasmakoma des Kometen P/Halley mittels Bildverarbeitung der Bochumer Photoplatten

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    1993-12-01

    Photographic and photoeletric observations of comet P/Halley's ion gas coma from CO+ at 4250 A were part of the Bochum Halley Monitoring Program, conducted from 1986 February 17, to April 17 at the European Southern Observatory on La Silla (Chile). In this spectral range it is possible to watch the continuous formation, motion and expansion of plasma structures. To observe the morphology of these structures 32 CO+ photos (glass plates) from P/Halley's comet have been analysed. They have a field of view of 28.6 X 28.6 degrees and were obtained from 1986 March 29, to April 17 with exposure times between 20 and 120 minutes. All photos were digitized with a PDS 2020 GM (Photometric Data System) microdensitometer at the Astronomisches Institut der Westfalischen Wilhelms-Universitaet in Muenster (one pixel = 25 X 25 microns approximately 46.88 X 46.88 arcsec). After digitization the data were reduced to relative intensities, and the part with proper calibrations were also converted to absolute intensities, expressed in terms of column densities using the image data systems MIDAS (Munich Image Data Analysis System; ESO - Image Processing Group, 1988) and IHAP (Image Handling And Processing; Middleburg, 1983). With the help of the Stellingwerf-Theta-Minimum-Method (Stellingwerf, 1978) a period of (2.22 +/- 0.09) days result from analysis of structures in the plasma-coma by subtracting subsequent images. The idea behind subtracting subsequent images is that rotation effects are only 10% phenomena on gas distribution. Difference images are than used to supress the static component of the gas cloud. The CO+ column density data (in molecules cm^-2) were compared with the data of CN column density from Schulz (1990) in all common days. The results show that the relations between CO+ and CN in average column density values (N_CO^+/N_CN) are 11.6 for a circular slit with average diameter (Phi) of 6.1 arcminute which corresponds to a distance from the nucleus (rho) equal to 6.3 X

  6. Van der Waals interaction between two crossed carbon nanotubes.

    PubMed

    Zhbanov, Alexander I; Pogorelov, Evgeny G; Chang, Yia-Chung

    2010-10-26

    The analytical expressions for the van der Waals potential energy and force between two crossed carbon nanotubes are presented. The Lennard-Jones potential between pairs of carbon atoms and the smeared-out approximation suggested by L. A. Girifalco (J. Phys. Chem. 1992, 96, 858) were used. The exact formula is expressed in terms of rational and elliptical functions. The potential and force for carbon nanotubes were calculated. The uniform potential curves for single- and multiwall nanotubes were plotted. The equilibrium distance, maximal attractive force, and potential energy have been evaluated. PMID:20863127

  7. Schröder Triangles, Paths, and Parallelogram Polyominoes

    NASA Astrophysics Data System (ADS)

    Pergola, Elisa; Sulanke, Robert A.

    1998-05-01

    This paper considers combinatorial interpretations for two triangular recurrence arrays containing the Schröder numbers s_n = 1, 1, 3, 11, 45 197, ... and r_n = 1, 2, 6, 22, 90, 394, ... , for n = 0, 1, 2, .... These interpretations involve the enumeration of constrained lattice paths and bicolored parallelogram polyominoes, called zebras. In addition to two recent inductive constructions of zebras and their associated generating trees, we present two new ones and a bijection between zebras and constrained lattice paths. We use the constructions with generating function methods to count sets of zebras with respect to natural parameters.

  8. Reconstruction of the lower lip in Van der Woude syndrome.

    PubMed

    Bozkurt, Mehmet; Kulahci, Yalcin; Zor, Fatih; Kapi, Emin; Yucetas, Altan

    2009-04-01

    Van der Woude syndrome (VWS) is a congenital disease characterized by labial cysts, accessory salivary glands, congenital lower lip pits, fistula, and paramedian sinuses, and is often accompanied by cleft lip and palate. VWS is an autosomal dominant craniofacial syndrome, which represents only lower lip pits due to variable gene expression. The principles of VWS surgery include excision of lower lip pits and accessory glands, reconstruction of the lip and nose, and correction of accompanying anomalies. In this article, we present a technique with dermal allograft reconstruction to prevent deformities after excision of the accessory gland in the lower lip pit. PMID:19325355

  9. Lower lip pits: van der woude or kabuki syndrome?

    PubMed

    David-Paloyo, Ferri P; Yang, Xuecai; Lin, Ju-Li; Wong, Fen-Hwa; Wu-Chou, Yah-Huei; Lo, Lun-Jou

    2014-11-01

    Kabuki syndrome (KS) is a multiple congenital anomaly/mental retardation syndrome with characteristic facial features. Despite more than 350 documented cases and recent correlation of MLL2 mutations as a genetic cause, its full clinical spectrum is still being defined. This report describes two patients who were initially diagnosed with Van der Woude syndrome (VWS) based on the presence of lower lip pits. However, this finding can occur with KS, albeit infrequently. For patients with lower lip pits, a thorough evaluation should be made to distinguish between VWS and KS, as there are differences in long-term prognosis. PMID:24088119

  10. Nonadditivity of van der Waals forces on liquid surfaces

    NASA Astrophysics Data System (ADS)

    Venkataram, Prashanth S.; Whitton, Jeremy D.; Rodriguez, Alejandro W.

    2016-09-01

    We present an approach for modeling nanoscale wetting and dewetting of textured solid surfaces that exploits recently developed, sophisticated techniques for computing exact long-range dispersive van der Waals (vdW) or (more generally) Casimir forces in arbitrary geometries. We apply these techniques to solve the variational formulation of the Young-Laplace equation and predict the equilibrium shapes of liquid-vacuum interfaces near solid gratings. We show that commonly employed methods of computing vdW interactions based on additive Hamaker or Derjaguin approximations, which neglect important electromagnetic boundary effects, can result in large discrepancies in the shapes and behaviors of liquid surfaces compared to exact methods.

  11. Hybrid Meson Potentials and the Gluonic van der Waals Force

    SciTech Connect

    O. Lakhina; E.S. Swanson

    2004-03-01

    The chromoelectric polarizability of mesons governs the strength of the gluonic van der Waals force and therefore of non-quark-exchange processes in hadronic physics. We compute the polarizability of heavy mesons with the aid of lattice gauge theory and the Born--Oppenheimer adiabatic expansion. We find that the operator product expansion breaks down at surprisingly large quarks masses due to nonperturbative gluodynamics and that previous conclusions concerning J/{psi}--nuclear matter interactions and J/{psi} dissociation in the quark-gluon plasma must be substantially modified.

  12. Spaceborne Autonomous and Ground Based Relative Orbit Control for the TerraSAR-X/TanDEM-X Formation

    NASA Technical Reports Server (NTRS)

    Ardaens, J. S.; D'Amico, S.; Kazeminejad, B.; Montenbruck, O.; Gill, E.

    2007-01-01

    TerraSAR-X (TSX) and TanDEM-X (TDX) are two advanced synthetic aperture radar (SAR) satellites flying in formation. SAR interferometry allows a high resolution imaging of the Earth by processing SAR images obtained from two slightly different orbits. TSX operates as a repeat-pass interferometer in the first phase of its lifetime and will be supplemented after two years by TDX in order to produce digital elevation models (DEM) with unprecedented accuracy. Such a flying formation makes indeed possible a simultaneous interferometric data acquisition characterized by highly flexible baselines with range of variations between a few hundreds meters and several kilometers [1]. TSX has been successfully launched on the 15th of June, 2007. TDX is expected to be launched on the 31st of May, 2009. A safe and robust maintenance of the formation is based on the concept of relative eccentricity/inclination (e/i) vector separation whose efficiency has already been demonstrated during the Gravity Recovery and Climate Experiment (GRACE) [2]. Here, the satellite relative motion is parameterized by mean of relative orbit elements and the key idea is to align the relative eccentricity and inclination vectors to minimize the hazard of a collision. Previous studies have already shown the pertinence of this concept and have described the way of controlling the formation using an impulsive deterministic control law [3]. Despite the completely different relative orbit control requirements, the same approach can be applied to the TSX/TDX formation. The task of TDX is to maintain the close formation configuration by actively controlling its relative motion with respect to TSX, the leader of the formation. TDX must replicate the absolute orbit keeping maneuvers executed by TSX and also compensate the natural deviation of the relative e/i vectors. In fact the relative orbital elements of the formation tend to drift because of the secular non-keplerian perturbations acting on both satellites

  13. Mapping SOC content and bulk density of a disturbed peatland relict with electromagnetic induction and DEM data

    NASA Astrophysics Data System (ADS)

    Altdorff, Daniel; Bechtold, Michel; van der Kruk, Jan; Tiemeyer, Bärbel; von Hebel, Christian; Huisman, Johan Alexander

    2014-05-01

    Peatlands represent a huge storage of soil organic carbon (SOC), and there is considerable interest to assess the total amount of carbon stored in these ecosystems. However, reliable field-scale information about peat properties, particularly SOC content and bulk density (BD) necessary to estimate C stocks, remains difficult to obtain. A potential way to acquire information on these properties and its spatial variation is the non-invasive mapping of easily recordable physical variables that correlate with peat properties, such as bulk electrical conductivity (ECa) measured with electromagnetic induction (EMI). However, ECa depends on a range of soil properties, including BD, soil and water chemistry, and water content, and thus results often show complex and site-specific relationships. Therefore, a reliable prediction of SOC and BD from ECa data is not necessarily given. In this study, we aim to explore the usefulness of Multiple Linear Regression (MLR) models to predict the peat soil properties SOC and BD from multi-offset EMI and high-resolution DEM data. The quality of the MLR models is assessed by cross-validation. We use data from a medium-scale disturbed peat relict (approximately 35ha) in Northern Germany. The potential explanatory variables considered in MLR were: EMI data of six different integral depths (approximately 0.25, 0.5, 0.6, 0.9, 1, and 1.80 m), their vertical heterogeneity, as well as several topographical variables extracted from the DEM. Ground truth information for SOC, BD content and peat layer thickness was obtained from 34 soil cores of 1 m depth. Each core was divided into several 5 to 20 cm thick layers so that integral information of the upper 0.25, 0.5, and 1 m as well as from the total peat layer was obtained. For cross-validation of results, we clustered the 34 soil cores into 4 classes using K-means clustering and selected 8 cores for validation from the clusters with a probability that depended on the size of the cluster. With the

  14. Improved analysis of the marine terraces and rivers of E-Corinth based on high-resolution Pleiades DEMs

    NASA Astrophysics Data System (ADS)

    de Gelder, Giovanni; Fernández-Blanco, David; Jara-Muñoz, Julius; Melnick, Daniel; Lacassin, Robin; Armijo, Rolando

    2016-04-01

    The Corinth rift, one of the fastest extending regions in the world, is a key area to understand the large-scale mechanics of an evolving rift system. It comprises a complicated en-echelon pattern of normal faults that shape a large, mostly asymmetric E-W-trending graben driven by large north-dipping faults located along the southern shore of the rift. The footwall of one of these faults in eastern Gulf of Corinth, the Xylokastro Fault, has been uplifted by ~2000m during Pleistocene times, which is ev