Science.gov

Sample records for stationaere und transiente

  1. Transiente Abstrahlung, Einkopplung und Streuung der Schlitzantennen im EMV-Umfeld

    NASA Astrophysics Data System (ADS)

    Ehlen, T.

    2014-11-01

    The radiation, reception and reradiating of the thin slot antenna with arbitrary transient time waveforms are derived in time domain and compared with numerical field simulation results. The equations are suitable for estimating typical pulsed EMI-Interference responses and penetration through loaded and not loaded slots in metal shields like bluetooth and wlan antennas including the radiation impedance. Examples are given for LEMP, NEMP and HPEM waveforms. The derived formulas are transferred in system theory based block diagrams.

  2. Fische und Fischerzeugnisse

    NASA Astrophysics Data System (ADS)

    Oehlenschläger, Jörg

    Fische und Fischerzeugnisse lassen sich gemäß den "Leitsätzen für Fische, Krebs- und Weichtiere und Erzeugnisse daraus" des Deutschen Lebensmittelbuches einteilen. Tiefgefrorene Fische werden von den "Leitsätzen für tiefgefrorene Fische, Krebs- und Weichtiere und Erzeugnisse daraus" und Salate mit Fleisch von Fischen, Krebs- und/oder Weichtieren durch Abschnitt II.B. der "Leitsätze für Feinkostsalate" abgedeckt. Zu nennen sind: Frischfische, Getrocknete Fische, Räucherfische, Gesalzene Fische, Erzeugnisse aus gesalzenen Fischen, Anchosen, Marinaden, Bratfischwaren, Kochfischwaren, Fischerzeugnisse in Gelee, Pasteurisierte Fischerzeugnisse, Fischdauerkonserven, Erzeugnisse aus Surimi, Krebstiere und Krebstiererzeugnisse, Weichtiere und Weichtiererzeugnisse und tiefgekühlte Fischereierzeugnisse.

  3. Information und Kommunikation

    NASA Astrophysics Data System (ADS)

    Wesoly, Michael; Ohlhausen, Peter; Bucher, Michael; Hichert, Rolf; Korge, Gabriele; Schnabel, Ulrich; Gairola, Arun; Reichwald, Ralf; Habicht, Hagen; Möslein, Kathrin; Schwarz, Torsten; Schönsleben, Paul; Scherer, Eric; Schloske, Alexander; Adlbrecht, Gerald; Federhen, Jens

    Wissen ist mittlerweile unverzichtbar für den entscheidenden Vorsprung auf dem Markt. Unabhängig davon, ob sich das Wissen in Innovationen, neuen Produkten und Dienstleistungen oder in der Verbesserung interner Unternehmensprozesse manifestiert: Wissen ist Treiber von Innovation, Wissen bringt Schnelligkeit und Wissen ist die Voraussetzung für Problemlösungen [40]. Wissensmanagement ist daher der Schlüssel für Unternehmenserfolg und bezeichnet den "bewussten und systematischen Umgang mit der Ressource Wissen und den zielgerichteten Einsatz von Wissen in der Organisation“ [6]. In dieser umfassenden Sichtweise ist Wissensmanagement ein Begriff, der Konzepte, Strategien und Methoden umfasst.

  4. Ingenieurgeologie: Grundlagen und Anwendung

    NASA Astrophysics Data System (ADS)

    Genske, Dieter D.

    Geplünderter Planet? Die Ingenieurgeologie ist ein junges, interdisziplinäres Fachgebiet. Es befasst sich mit der Wechselwirkung zwischen Geosphäre und Mensch. Der Autor stellt Georisiken vor und diskutiert die Folgen menschlicher Eingriffe in die Natur. Er thematisiert aktuelle Herausforderungen und entwirft nachhaltige Lösungskonzepte für verschiedene Problembereiche: z.B. Naturgefahren wie Hangrutschungen und Bergfälle, die Ausbeute natürlicher Ressourcen, Bau- und Sanierungsvorhaben. Fallbeschreibungen und ausgearbeitete Beispiele vertiefen das Verständnis für diesen neuen, zukunftsweisenden Zweig der Wissenschaft.

  5. Lymph- und Immunsystem

    NASA Astrophysics Data System (ADS)

    Perry, Steven F.

    Alle Lebewesen müssen sich gegen Eindringlinge wehren. Ihre Abwehrmechanismen wirken auf verschiedenen Ebenen, von übergeordneten Feindvermeidungsstrategien und Putzverhalten bis hin zu molekularen Erkennungs- und Tötungsmechanismen. Da Eindringlinge über Kontaktflächen mit der Außenwelt, wie z.B. Körperoberfläche, Darmwand und Atmungsoberflächen, in den Organismus gelangen, sind an diesen Stellen immer primäre Abwehrmechanismen zu finden. Dazu zählen (1) Schleimabsonderung (Schleimhäute bei allen Schädeltieren, Fischkiemen, epidermale Schleimdrüsen (Fische, Amphibien)), (2) Stoffwechselgifte und antibakteriell wirkende Substanzen in der Haut (Fische, Amphibien) und im Speichel (Amnioten), (3) Flimmerepithelien zum Abtransport von Eindringlingen und (4) starke Keratinbildung in der mehrschichtigen Epidermis und schützende Strukturen wie Schuppen, Federn und Haare (Amnioten) (S. 20). Auch die starke Säurebildung im Magen kann als Schutz gegen Eindringlinge betrachtet werden.

  6. Zwergsatelliten und Sternriesen

    NASA Astrophysics Data System (ADS)

    Baade, Dietrich; Kuschnig, Rainer

    2017-03-01

    Leuchtkräftige Sterne sind schwierig: Fär Fotometrie mit großen Teleskopen sind sie zu hell, und ihre geringe Zahl macht konventionelle Lösungen unwirtschaftlich, besonders im Weltraum, wo die äußerste Präzision gegeben wäre. Mit einer Mini-Armada von Nanosatelliten haben Ingenieure und Astronomen aus Kanada, Österreich und Polen nun die Lösung gefunden - auch schon für viele wissenschaftliche Fragen.

  7. Neuausrichtung und Konsolidierung

    NASA Astrophysics Data System (ADS)

    Grohmann, Heinz

    Mit der Wahl von Wolfgang Wetzel zum Vorsitzenden der Deutschen Statistischen Gesellschaft im Jahre 1972 begann eine 32jährige Ära, in der die praktische und die theoretische Statistik in einem ausgewogenen Verhältnis gepflegt wurden. Ein regelmäßiger vierjähriger Wechsel im Vorsitz stärkte die Gemeinschaft und die praktische wie die wissenschaftliche Arbeit gleichermaßen. Die jährlichen Hauptversammlungen behandelten gesellschaftlich aktuelle wie zukunftsorientierte Themen, und die Ausschüsse sowie weitere Veranstaltungen gaben Gelegenheit zur Förderung und Pflege einer Vielzahl von Arbeitsgebieten der Statistik. Darüber wird nicht nur in diesem Kapitel, sondern auch in den Teilen II und III des Bandes berichtet.

  8. Tensoren und Felder

    NASA Astrophysics Data System (ADS)

    Dirschmid, Hans J.

    Das Lehrbuch soll Studierende mit Grundkenntnissen der Differential- und Integralrechnung in die klassische Feldtheorie mit modernen mathematischen Methoden einführen. Dementsprechend ist die Tensoranalysis das mathematische Thema, das Prinzip der Relativität das physikalische. Aus didaktischen Erwägungen gliedert sich der Text in zwei Teile. Um den Leser mit den Objekten vertraut zu machen, wird zunächst der affine und euklidische Raum zugrundegelegt, um verallgemeinernd zur Geometrie auf Mannigfaltigkeiten und Riemannschen Räumen überleiten zu können. Im Anschluß an die mathematische Theorie wird in die spezielle und allgemeine Relativitätstheorie eingeführt, wobei die Geometrie der Raum-Zeit, die Grundgesetze der Elektrodynamik und der Gravitation sowie Folgerungen zur Sprache kommen.

  9. Falten und fliegen: Papierflieger und ihre Physik

    NASA Astrophysics Data System (ADS)

    Gruber, Werner

    2004-09-01

    Mit Papierfliegern können wichtige Eigenschaften der Aerodynamik anschaulich vermittelt werden: ein Blatt Papier, ein paar Faltungen und schon kann man experimentieren. Allerdings sind beim Trimmen des Fliegers einige Punkte zu beachten. Besonders wichtig ist die Y-Stellung der Flügel, die ihm Flugstabilität verleiht. Ist der Flieger fertig, dann gilt es, die dem Modell am besten angepasste Wurftechnik herauszufinden. Dazu variiert man Wurfgeschwindigkeit und Abwurfwinkel. Den Boden kann ein Papierflieger auf vier prinzipiell verschiedenen Flugkurven erreichen: Optimal ist die Gerade, dann fliegt er am weitesten.

  10. Messung und Analyse

    NASA Astrophysics Data System (ADS)

    Bathelt, Hartmut; Scheinhardt, Michael; Sell, Hendrik; Sottek, Roland; Guidati, Sandro; Helfer, Martin

    Für die Beurteilung von Akustik und Fahrkomfort eines Fahrzeugs gilt in der Fahrzeugentwicklung immer noch der alte Grundsatz: "Der Kunde fährt nicht am Prüfstand, sondern auf der Straße“. Daher werden Gesamtbeurteilungen des Entwicklungsstandes und Konkurrenzvergleiche (Benchmarking) nach wie vor auf der Straße durchgeführt, meist auf ausgewählten Fahrbahnen am Prüfgelände oder im Rahmen der regelmäßigen Winter- und Sommererprobungen unter extremen Witterungsverhältnissen.

  11. Getreide, Brot und Feine Backwaren

    NASA Astrophysics Data System (ADS)

    von Grabowski, Hans-Uwe; Rolfe, Birgit

    Getreide und Getreideerzeugnisse sind ebenso wie Brot und Feine Backwaren nach dem Lebensmittel- und Futtermittel-Gesetzbuch (LFGB) [1] Lebensmittel im Sinne des Artikels 2 der VO (EG) Nr. 178/2002 (BasisVO) (s. auch Kap. 1.6/2.4.1/3.2). Gesetzlich festgelegte Begriffsbestimmungen gibt es für diese Lebensmittel nicht. Man muss sich daher allgemeiner Verkehrsauffassungen bedienen, wie sie von der Deutschen Lebensmittelbuch-Kommission in Form von Leitsätzen erarbeitet und veröffentlicht wurden [2]. Der Gesundheitsschutz und der Schutz des Verbrauchers vor Täuschung sind in der Basis-VO und dem LFGB geregelt.

  12. Instandhaltung und Normung

    NASA Astrophysics Data System (ADS)

    Rosenkranz-Wuttig, Angela

    Das DIN Deutsches Institut für Normung e.V. ist ein eingetragener Verein mit Sitz in Berlin. Das DIN erarbeitet gemeinsam mit den Experten der interessierten Kreise Normen und Standards als Dienstleistung für Wirtschaft, Staat und Gesellschaft. Die Kenntnis entsprechender Normen, Standards oder Regeln, sowie deren richtiger Einsatz, ist unter den heutigen Marktbedingungen für jedes Unternehmen ein nicht zu unterschätzender wirtschaftlicher Faktor. Normen schaffen Effizienz bei Produktionsabläufen und sorgen durch eine gleichbleibende sowie vergleichbare Produktqualität für Vertrauen bei den Endverbrauchern. Darüber hinaus stehen Normen unter rechtlichen Aspekten für mehr Sicherheit - Hersteller erreichen bei Anwendung und Einhaltung von Normen ein hohes Maß an rechtlicher Absicherung. Das DIN vertritt die deutschen Interessen in den europäischen und weltweiten Normungsorganisationen, siehe Abb. 1. Zuständig für die elektrotechnische Normung in Deutschland sowie als deutscher Repräsentant in den übernationalen Gremien ist die DKE Deutsche Kommission Elektrotechnik Elektronik Informationstechnik im DIN und VDE.

  13. Datenintegration und Deduplizierung

    NASA Astrophysics Data System (ADS)

    Bleiholder, Jens; Schmid, Joachim

    In Unternehmen liegen viele Daten heutzutage immer seltener vollständig an einem einzigen physikalischen Ort vor, sondern sind weltweit verteilt. Dies liegt zum einen an der immer besser gewordenen Infrastruktur, die eine solche Verteilung auf einfache Art und Weise ermöglicht, und zum anderen an der Tatsache, dass viele Unternehmen weltweit tätig sind. So fallen Daten weltweit an, werden aber jeweils lokal - vor Ort - gespeichert. Daher müssen oft mehrere Datenquellen genutzt werden, um einen aktuellen, vollständigen und genauen Überblick über die vorhandenen Daten zu gewinnen. Datenintegration hilft, indem sie Daten aus mehreren Quellen zusammenführt und einheitlich darstellt. Diese integrierten Daten können genutzt werden, um sich einen Überblick über das Unternehmen zu verschaffen, z.B. wenn Unternehmen fusionieren und nur noch eine Kundendatenbank bestehen bleiben soll, oder wenn zu einem Kunden die Daten aus den verschiedenen Fachabteilungen zusammengeführt werden sollen. Anhand eines solchen Beispiels, der Integration von Kundendaten zu Kfz- und Lebensversicherungen erläutern wir im Folgenden einzelne Techniken.

  14. Statistik in Naturwissenschaft und Technik

    NASA Astrophysics Data System (ADS)

    Wilrich, Peter-Theodor

    Mit dem Aufschwung von Naturwissenschaft und Technik zu Beginn des 19. Jahrhunderts entstand die mathematische Statistik, angeregt aus der Geodäsie (wie die Methode der kleinsten Quadrate) und der Anthropologie (wie die statistische Analyse mehrdimensionaler Beobachtungen und ihrer stochastischen Abhängigkeiten). Im Gegensatz zu den Wirtschafts- und Sozialwissenschaften, in denen Daten vorwiegend aus Beobachtungsstudien gewonnen werden, stehen in den Naturwissenschaften Experimente im Vordergrund. Daher gehört die statistische Versuchsplanung zu den insbesondere in Naturwissenschaft und Technik angewendeten statistischen Methoden, aber auch die Extremwertstatistik und Lebensdaueranalysen sowie die Methoden der räumlichen Statistik (insbesondere in der Umweltforschung). Im 20. Jahrhundert wurden Stichprobenpläne und Regelkarten (Kontrollkarten) zur Prozessregelung als Hilfsmittel der statistischen Qualitätssicherung entwickelt. Diese Methodenbündel, mit denen sich der Ausschuss Statistik in Naturwissenschaft und Technik immer wieder befasst, werden im Folgenden vorgestellt.

  15. Tipps und Tricks

    NASA Astrophysics Data System (ADS)

    Häger, Wolfgang; Bauermeister, Dirk

    Hier wollen wir einige uns nützlich erscheinende Hinweise zur Arbeit mit dem Inventor geben. Dabei geht es vor allem darum, das Arbeiten mit dem Inventor zu vereinfachen. Die Beispiele stellen eine unvollständige Aufzählung dar und sollen dazu anregen, nach alternativen Vorgehensweisen zu suchen (hier sei noch einmal ausdrücklich auf das Internet verwiesen).

  16. Arbeitsgestaltung und Mitarbeiterqualifizierung

    NASA Astrophysics Data System (ADS)

    Weiss-Oberdorfer, Werner; Hörner, Barbara; Holm, Ruth; Pirner, Evelin

    Die Wertkette gliedert ein Unternehmen in strategisch relevante Tätigkeiten, um dadurch Kostenverhalten sowie vorhandene und potenzielle Differenzierungsquellen zu verstehen. Wenn ein Unternehmen diese strategisch wichtigen Aktivitäten billiger oder besser als seine Konkurrenten erledigt, verschafft es sich einen Wettbewerbsvorteil." Michael Porter, 1985

  17. Wirkstoffe, Medikamente und Mathematische Bildverarbeitung

    NASA Astrophysics Data System (ADS)

    Bauer, Günter J.; Lorenz, Dirk A.; Maaß, Peter; Preckel, Hartwig; Trede, Dennis

    Die Entwicklung neuer Medikamente ist langwierig und teuer. Der erste Schritt ist hierbei die Suche nach neuen Wirkstoffkandidaten, die für die Behandlung bislang schwer therapierbarer Krankheiten geeignet sind. Hierfür stehen der Pharma- und Biotechnologieindustrie riesige Substanzbibliotheken zur Verfügung. In diesen Bibliotheken werden die unterschiedlichsten Substanzen gesammelt, die entweder synthetisch hergestellt oder aus Pilzen, Bakterienkulturen und anderen Lebewesen gewonnen werden können.

  18. Zusammenfassung und Ausblick

    NASA Astrophysics Data System (ADS)

    Knopp, Lothar; Wiegleb, Gerhard

    Mit dem vorliegenden Buch wird als Ergebnis eines durch die Deutsche BundesstiftungUmwelt (DBU) geförderten Forschungsprojektes an der Brandenburgischen Technischen Universität Cottbus eine erste Standardisierung der Vorgehensweise zur Erfassung, Risikoabschätzung und Bewertung eines Biodiversitätsschadens nach dem Umweltschadensgesetz (USchadG) vorgelegt. Damit kann eine erste Bewertung potentieller Schadenssituationen vorgenommen werden. Die Nutzung der hier erarbeiteten Vorgehensweise bietet sich daher für all diejenigen an, die mit der Frage einer möglichen Haftung für Biodiversitätsschäden nach dem USchadG konfrontiert sind, seien es die Unteren und Oberen Naturschutzbehörden der Länder, die Schadensversicherer, die potentiell Haftenden oder die Naturschutzverbände.

  19. Pyropheophorbide und a as a catabolite of ethylene-induced chlorophyll und a degradation

    SciTech Connect

    Shimokawa, Keishi; Hashizume, Akihito ); Shioi, Yuzo )

    1990-05-01

    An enzyme extract prepared from ethylene-induced degreening Citrus fruits contains chlorophyll (Chl) degrading enzymes. The fate of Chl carbons during an enzymatic degradation was investigated using Chl {und a}-{sup 14}C. Accompanying the disappearance of labelled Chl {und a}, pheophorbide {und a} and pyropheophorbide {und a} appeared and accumulation of pyropheophorbide {und a} was observed. HydroxyChl {und a} was also detected, but this is thought to be an artifact during chromatography. Unlike ethylene-induced Citrus fruits (in vivo), further degradation of pyropheophorbide {und a} did not occur in vitro enzyme system. This suggests that there is a lack of enzyme(s) and/or cofactor(s) for further degradation. It is concluded that Chl {und a} degraded enzymatically by the following order: Chl {und a}, chlorophyllide {und a}, pheophorbide {und a} and pyropheophorbide {und a}.

  20. Organe der Osmoregulation und Exkretion

    NASA Astrophysics Data System (ADS)

    Møbjerg, Nadja

    Die meisten Schädeltiere sind in der Lage, die Wasser- und Ionenkonzentration ihres Innenmilieus zu regulieren, sind also im Hinblick auf ihren Ionenhaushalt weitgehend unabhängig von der Umgebung. Sie halten die Konzentration von Wasser und anorganischen Ionen in ihren Körperflüssigkeiten (interstitielle Flüssigkeit und Blut) innerhalb enger Grenzen konstant (Osmoregulierer). Schleim aale (Myxinoida) können zwar die Konzentration einzelner anorganischer Ionen regulieren, sind aber insgesamt der hohen Osmolarität des Meerwassers angepasst, also isoosmostisch zu diesem. Isoosmotisch oder leic ht hyperosmostisch zur Umgebung sind auch marine Neoselachier und Latimeria chalumnae (Actinistia), die dazu organische Osmolyte (Harnstoff und Trimethylaminoxid) im Blut akkumulieren (Osmokonformer). Bei anderen aquatischen Schädeltieren sind die Körperflüssigkeiten zur Umgebung hypoosmotisch (im Meerwasser) — sie halten Wasser zurück und scheiden anorganiche Ionen aus — oder hyperosmotisch (im Süßwasser), indem sie Wasser abgeben und anorganische Ionen aufnehmen.

  1. Beschallungstechnik, Beschallungsplanung und Simulation

    NASA Astrophysics Data System (ADS)

    Ahnert, Wolfgang; Goertz, Anselm

    Die primäre Aufgabe einer Lautsprecheranlage ist es, Musik, Sprache oder auch Signaltöne und Geräusche wiederzugeben. Diese können von einem Tonträger kommen (CD, Sprachspeicher), von einem anderen Ort übertragen (Zuspielung über Radio, TV, Telefon) oder vor Ort erzeugt werden. Letzteres umfasst Konzerte, Ansprachen, Durchsagen oder künstlerische Darbietungen, bei denen es meist darum geht, eine bereits vorhandene Quelle einer größeren oder weiter verteilten Anzahl von Personen zugänglich zu machen.

  2. Entwicklung und Formulierung der Unternehmensstrategie

    NASA Astrophysics Data System (ADS)

    Crespo, Isabel; Bergmann, Lars; Lacker, Thomas

    Ursprünglich stammt der Begriff "Strategie“ aus dem Altgriechischen: "strategos“ bedeutete "Heer“, "Heeresmacht“ und damit auch "konzentrierte Kraft“; das Wort "agein“ bedeutete "tun, machen, treiben“. Ein Stratege war also eine Person, die ein Heer führte und damit Kraft, Macht und Stärke konzentrierte und einsetzen konnte. Strategie bezeichnete dementsprechend die Maßnahmen, die in dieser Funktion entwickelt wurden. Daher ist es leicht verständlich, dass der Begriff Strategie bis in die Mitte des letzten Jahrhunderts in erster Linie militärisch verstanden wurde. Anschließend wurde der Begriff in weiteren Bereichen, wie beispielsweise der Unternehmensführung, verwendet. Im betriebswirtschaftlichen Sinne bedeutet der Begriff Strategie die langfristig geplante Verhaltensweise eines Unternehmens zur Erreichung seiner Ziele.

  3. Welt und Wirkungsprinzip (2nd Aufl.)

    NASA Astrophysics Data System (ADS)

    Landgraf, Werner

    2010-03-01

    Modell einer kausalen Bewirkung der Welt, und logische, geometrische, physikalische Interprätation dieser Kausalmenge und Fortwirkung der frühsten ihrer sukzessiv als echt Neues bewirkten und durch Vorhandenes oder Späteres nicht darstellbaren oder widerrufbaren Ereignisse als Dimensionen und sie verkörpernde primäre Naturkräfte, mit Korrespondenz zur beobachteten Welt und ihrer grundlegendsten Eigenschaften. Wirklich ist nur was wirkt, wo und wie. Entsprechend ist im Bogenelement statt der Eigenzeit die variante Anzahl Wirkungen relevant, 0 ≈ 1/h2 dS2 - 1/tpl2 (dt2 - 1/c2 {dq12 + G02/G2 [dq2,32 - ...]}) mit G0 = c4lpl/Epl ≈ G. Die heutigen Dimensionen und Naturkräfte entstanden in dieser Reihenfolge, haben 'komplementäre' aber gleichwertige statische und dynamische Aspekte, entsprechend ihren Termen in Bogenelement bzw. Vierervektor, aus derem Vergleich sowie mit denen ihrer Nachbarn folgen Grundgleichungen bzw. Erhaltungssätze. Jeweils individuelle Eigenschaften wie ihre Naturkonstante konkretisieren sie und tragen zu gattungsmäßigen wie globale Affinität und Äquivalenzen bei. Ältestes Gebiet oder räumlicher Rand jeder Dimension sind die ersten vom Vorgänger bewirkten Ereignisse, selbst raumzeitlicher Ursprung des Nachfolgers, dort einmalig und ewig maximal rotverschoben fortwirkend und nicht lokalisierbar, um neue Elementareinheiten verschieden und lichtartig mit deren Verhältnis oder dem ihrer globalen Zustandsgrößen als konstanten Anfangsimpuls, Expansion, Längen- oder Ereignisdichte zueinander. Der Übergang vom diskreten Modell weniger Informationen zum Kontinuum und die Korrespondenz zur Physik ist problemlos, Details wie ein kontinuierlicher, abrupter oder ganz fehlender Abfall der Metrik beim ältesten Gebiet sind aber nur durch Beobachtungen entscheidbar. Erörtert werden allgemeine und individuelle Eigenschaften und ihre Konsequenzen der Dimensionen mit ihren Kräften, selbst und im Verhältnis zueinander, etwa ihrer begrenzten

  4. Restaurierung von Seen und Renaturierung von Seeufern

    NASA Astrophysics Data System (ADS)

    Grüneberg, Björn; Ostendorp, Wolfgang; Leßmann, Dieter; Wauer, Gerlinde; Nixdorf, Brigitte

    Süßwasserseen haben als ökosysteme und Lebensraum für Pflanzen und Tiere eine herausragende Bedeutung für die Artenvielfalt auf der Erde und prägen als Landschaftselemente unsere natürliche Umwelt. Seen fungieren als natürliche Stoffsenken, vor allem für Kohlenstoff und Nährstoffe, aber auch als Senken für in ihren Einzugsgebieten emittierte gelöste und feste Schadstoffe. Darüber hinaus ist Wasser eine wichtige Naturressource. Süßwasserseen stellen in den meisten Regionen der Erde lebenswichtige Quellen für die Versorgung mit Trinkwasser und tierischem Eiweiß (Fischfang) dar. Sie dienen als Wasserspeicher für die landwirtschaftliche und industrielle Nutzung. Auch für Erholungsaktivitäten des Menschen kommt ihnen eine große Bedeutung zu.

  5. Bewegungsapparat: Postcraniales Skelett und Muskulatur

    NASA Astrophysics Data System (ADS)

    Fischer, Martin S.

    Der Bewegungsapparat bestimmt die Form des Wirbeltierkörpers. So lässt sich z. B. aus der Gestalt eines Fisches auf seine bevorzugt e Schwimmweise schließen (S. 61). Bei den aquatisch en Schädeltieren dominiert die Fortbewegung mit axialem Antrieb; bei den meisten Tetrapoda findet sich eine Kombination aus axialem Antrieb und Bewegung durch Gliedmaßen. Selbst beim höchst spezialisierten Gang, der bipeden Bewegung des Menschen, sind Torsionsbewegungen des Rumpfes noch maßgeblich und bestimmen auch die Grundform des menschlichen Körpers (z. B. die Taille). Obwohl die verschiedenen Antriebsmechanismen eine funktionelle Einheit bilden, werden im Folgenden das Axialskelett sowie der Schulter- und Beckengürtel mit den zugehörigen Extremitäten getrennt besprochen.

  6. Kosmologie und Teilchenphysik.

    NASA Astrophysics Data System (ADS)

    Appenzeller, I.

    This book is a selection of 17 articles published in the journal "Spektrum der Wissenschaft". The original English versions of the papers were first published in "Scientific American". Contents: 1. Einführung (I. Appenzeller). 2. Sehr große Strukturen im Universum (J. O. Burns). 3. Die großräumigen Eigenbewegungen der Galaxien (A. Dressler). 4. Dunkle Materie im Universum (L. M. Krauss). 5. Der doppelte Beta-Zerfall (M. K. Moe, S. P. Rosen). 6. Quark-Lepton Familien (D. B. Cline). 7. Beschleunigerexperimente testen kosmologische Theorien (D. N. Schramm, G. Steigman). 8. Das Rätsel der kosmologischen Konstanten (L. Abbott). 9. Das Higgs-Boson (M. J. G. Veltman). 10. Die Suche nach dem Protonenzerfall (J. M. LoSecco, F. Reines, D. Sinclair). 11. Das inflationäre Universum (A. H. Guth, P. J. Steinhardt). 12. Die fünfte Dimension (E. Schmutzer). 13. Die verborgenen Dimensionen der Raumzeit (D. Z. Freedman, P. van Nieuwenhuizen). 14. Ist die Natur supersymmetrisch? (H. E. Haber, G. L. Kane). 15. Schwerkraft und Antimaterie (T. Goldman, R. J. Hughes, M. M. Nieto). 16. Superstrings (M. B. Green). 17. Kosmische Strings (A. Vilenkin).

  7. Der Forschungsflughafen und das Institut fuer Luft- und Raumfahrtsysteme

    DTIC Science & Technology

    2007-11-02

    Broitzem: Deutsche Verkehrsfliegerschule Völkenrode: Deutsche Forschungsanstalt für Luftfahrt (DFL) Waggum: Technische Hochschule Grundsteinlegung...Forschungsflughafen Aerodata Deutsches Zentrum für Luft- und Raumfahrt DLR VW Air Services TU Braunschweig Luftfahrt -Bundesamt LBA Deutscher Aeroclub

  8. Lineare und verzweigte Blockcopolymere aus Polypeptiden und synthetischen Polymeren

    NASA Astrophysics Data System (ADS)

    Kukula, Hildegard

    2001-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von linearen und verzweigten amphiphilen Polypeptid-Blockcopolymeren. Die Frage nach dem Einfluss der Topologie und Konformation der Blockcopolymere auf die supramolekularen und kolloidalen Eigenschaften bildete einen wichtigen Aspekt bei den Untersuchungen. Die Blockcopolymere wurden nach einem mehrstufigen Reaktionsschema durch Kombination von anionischer und ringöffnender Polymerisation von Aminosäuren-N-Carboxyanhydriden (NCA) synthetisiert. Die Untersuchung der Polypeptid-Blockcopolymere hinsichtlich ihres Aggregationsverhaltens in fester Phase sowie in verdünnter wässriger Lösung erfolgte mittels Streumethoden (SAXS, WAXS, DLS) sowie abbildender Methoden (TEM). Durch Einsatz der Blockcopolymere als polymere Stabilisatoren in der Emulsionspolymerisation wurden Oberflächen funktionalisierte Latizes erhalten. Als Beispiel für eine pharmazeutische Anwendung wurden bioverträgliche Polypeptid-Blockcopolymere als Wirkstoff-Trägersysteme in der Krebstherapie eingesetzt. This work describes the synthesis and characterization of linear and branched polypeptide block copolymers having amphiphilic character. The studies focused on the impact of the block copolymers' conformation and architecture on the supramolecular and colloidal properties. The polypeptide block copolymers were prepared in a multi-step process involving the anionic synthesis of (poly)amino-functional polymers (polystyrene and polybutadiene) which where used as macroinitiators for the ring-opening polymerization of N-carboxyanhydrides (NCA) of protected a-aminoacids. Supramolecular structures of the block copolymers in the solid state as well as in diluted aqueous solution were investigated using scattering (SAXS, WAXS, DLS) and microscopic (TEM) methods. Both linear and branched polypeptide block copolymers were used as polymeric stabilizers in the emulsion polymerization of styrene to yield polypeptide

  9. Transient tachypnea - newborn

    MedlinePlus

    TTN; Wet lungs - newborns; Retained fetal lung fluid; Transient RDS; Prolonged transition; Neonatal - transient tachypnea ... As the baby grows in the womb, the lungs make a special fluid. This fluid fills the ...

  10. Transient drainage summary report

    SciTech Connect

    1996-09-01

    This report summarizes the history of transient drainage issues on the Uranium Mill Tailings Remedial Action (UMTRA) Project. It defines and describes the UMTRA Project disposal cell transient drainage process and chronicles UMTRA Project treatment of the transient drainage phenomenon. Section 4.0 includes a conceptual cross section of each UMTRA Project disposal site and summarizes design and construction information, the ground water protection strategy, and the potential for transient drainage.

  11. Mittelwert- und Arbeitstaktsynchrone Simulation von Dieselmotoren

    NASA Astrophysics Data System (ADS)

    Zahn, Sebastian

    Getrieben durch die immer restriktiveren Anforderungen an das Emissions- und Verbrauchsverhalten moderner Verbrennungsmotoren steigt die Komplexität von Motormanagementsystemen mit jeder Modellgeneration an. Damit geht nicht nur eine Zunahme des Softwareumfangs von Steuergeräten sondern zugleich ein deutlicher Anstieg des Applikations-, Vermessungs- und Testaufwandes einher. Zur Effizienzsteigerung des Software- und Funktionsentwicklungsprozesses haben sich daher in der Automobilindustrie sowie in Forschungsinstituten verschiedene modell- und simulationsbasierte Methoden wie die Model-in-the-Loop (MiL) Simulation, die Software-in-the-Loop (SiL) Simulation, das Rapid Control Prototyping (RCP) sowie die Hardware-in-the-Loop (HiL) Simulation etabliert.

  12. Topika und deren Einsatz in der Dermatologie.

    PubMed

    Wohlrab, Johannes

    2016-11-01

    Grundkenntnisse zur Zusammensetzung und den regulatorischen Hintergründen von Topika gehören zu den alltäglich benötigten Herausforderungen dermatologisch-ärztlichen Handelns. Ein professioneller und indikationsgerechter Umgang bei der Auswahl, Verordnung und Anwendung topischer Präparate ist somit Voraussetzung für eine verantwortungsvolle fachärztliche Tätigkeit. Dabei bereiten die regulatorische Zuordnung (Arzneimittel, Medizinprodukt, Kosmetikum), die Feststellung der Erstattungsfähigkeit durch die GKV und die unzureichende Kennzeichnung des Vehikelsystems einzelner Präparate nicht selten Probleme. Bestreben sollte es sein, neben der Wahl des geeigneten Wirkstoffs und der geeigneten Konzentration ein an die Indikation der Therapie angepasstes galenisches System auszuwählen, um dessen Eigenwirkung für den therapeutischen Effekt nutzen zu können. Bei der Verschreibung von Rezepturarzneimitteln sollte nach Möglichkeit immer auf eine standardisierte Rezeptur (Magistralrezeptur) zurückgegriffen werden. Durch die Vielzahl der möglichen Inhaltsstoffe und der sich daraus ergebenden Komplexität eines galenischen Systems ist eine willkürliche Manipulation durch qualitative oder quantitative Veränderungen einzelner Komponenten mit hohen Risiken für eine Instabilität und damit für Sicherheit und Sinnhaftigkeit verbunden. Eine optimierte Anwendung von Topika setzt zudem Grundlagenkenntnisse zur Pharmakokinetik und zur evidenzbasierten Therapieplanung voraus.

  13. Ruhende Flüssigkeiten und Gase

    NASA Astrophysics Data System (ADS)

    Heintze, Joachim

    Das mechanische Verhalten von Flüssigkeiten und Gasen ist dadurch gekennzeichnet, dass sie keine statische Schubfestigkeit besitzen, andernfalls würden sie nicht beginnen, zu fließen. In ruhenden Flüssigkeiten und Gasen können daher keine Schubspannungen bestehen:

  14. Physik gestern und heute Das Eiskalorimeter

    NASA Astrophysics Data System (ADS)

    Heering, P.

    2003-07-01

    Kalorimetrische Messungen gehören heute zum experimentellen Standardrepertoire im Bereich der Thermodynamik und der physikalischen Chemie. Das erste Gerät für derartige Messungen entwickelten Ende des 18. Jahrhunderts die französischen Wissenschaftler Antoine Laurent Lavoisier und Pierre Simon de Laplace.

  15. Quantitative Analyse und Visualisierung der Herzfunktionen

    NASA Astrophysics Data System (ADS)

    Sauer, Anne; Schwarz, Tobias; Engel, Nicole; Seitel, Mathias; Kenngott, Hannes; Mohrhardt, Carsten; Loßnitzer, Dirk; Giannitsis, Evangelos; Katus, Hugo A.; Meinzer, Hans-Peter

    Die computergestützte bildbasierte Analyse der Herzfunktionen ist mittlerweile Standard in der Kardiologie. Die verfügbaren Produkte erfordern meist ein hohes Maß an Benutzerinteraktion und somit einen erhöhten Zeitaufwand. In dieser Arbeit wird ein Ansatz vorgestellt, der dem Kardiologen eine größtenteils automatische Analyse der Herzfunktionen mittels MRT-Bilddaten ermöglicht und damit Zeitersparnis schafft. Hierbei werden alle relevanten herzphysiologsichen Parameter berechnet und mithilfe von Diagrammen und Graphen visualisiert. Diese Berechnungen werden evaluiert, indem die ermittelten Werte mit manuell vermessenen verglichen werden. Der hierbei berechnete mittlere Fehler liegt mit 2,85 mm für die Wanddicke und 1,61 mm für die Wanddickenzunahme immer noch im Bereich einer Pixelgrösse der verwendeten Bilder.

  16. Dentalwerkstoffe und Dentalimplantate - Teil 2

    NASA Astrophysics Data System (ADS)

    Faltermeier, Andreas

    Wie in allen Bereichen der Medizin findet auch in der Zahnmedizin eine kontinuierliche Weiterentwicklung der verwendeten Werkstoffe statt. Gerade für Zahnersatz werden Werkstoffe gesucht, die zum einen ästhetisch, zum anderen haltbar und darüber hinaus auch körperverträglich sind. Auch steigt immer mehr der Wunsch der Patienten nach ästhetischen und zugleich biokompatiblen Materialien. Wurde früher fast ausschließlich als Füllungsmaterial im Seitenzahngebiet quecksilberhaltiges Amalgam verwendet, hat der Zahnarzt heutzutage eine große Auswahl an verschiedenen zahnfarbenen Materialien: zum einen werden sog. Komposite verwendet, das aus einer Polymermatrix mit eingebetteten Füllstoffen besteht, zum anderen können diverse Dentalkeramiken verwendet werden. Besonders die Verwendung von Hochleistungskeramiken, wie beispielsweise Zirkonoxid, das sich bereits als Bremsscheiben für Sportwägen, Hitzeschilde im Space Shuttle und als Kugelköpfe künstlicher Hüftgelenke bewährt hat, spielt heutzutage eine große Rolle bei der Verdrängung des Metalls aus der Mundhöhle. War es früher nur möglich, einen verloren gegangen Zahn mittels einer Brücke, die ein Beschleifen der Nachbarzähne zur Folge hat, oder durch herausnehmbaren Zahnersatz zu ersetzen, ist es heutzutage mit der modernen Implantologie möglich, Zahnersatz zahnschonend einzugliedern. Auch kann mittels Dentalimplantaten dem Wunsch vieler Patienten nach festem Zahnersatz anstelle eines herausnehmbaren Zahnersatzes entsprochen werden. So kann mit Hilfe neuer biokompatiblen Werkstoffe sowohl der ästhetische Anspruch befriedigt als auch das Selbstwertgefühl vieler Patienten angehoben werden.

  17. Aufbau und Anpassung der Motorsteuerungs-Software für Otto- und Dieselmotoren

    NASA Astrophysics Data System (ADS)

    Stuhler, Harald; Ricken, Volker; Diener, René

    Die Erfüllung steigender Kundenansprüche und strenger gesetzlicher Vorgaben hinsichtlich der Verringerung des Kraftstoffverbrauchs, der Reduzierung von Schadstoffemissionen, der Erhöhung von Fahrsicherheit, Fahrleistung und Fahrkomfort ist untrennbar mit dem Einzug elektronischer Systeme in moderne Kraftfahrzeuge verbunden. Die elektronischen Systeme bestimmen zunehmend den Kundennutzen und werden für die Differenzierung der Automobilhersteller untereinander immer wichtiger. Daher sind sie ein wesentlicher Erfolgsfaktor moderner Kraftfahrzeuge.

  18. [Transient epileptic amnesia].

    PubMed

    Muramatsu, Kazuhiro; Yoshizaki, Takahito

    2016-03-01

    Transient amnesia is one of common clinical phenomenon of epilepsy that are encountered by physicians. The amnestic attacks are often associated with persistent memory disturbances. Epilepsy is common among the elderly, with amnesia as a common symptom and convulsions relatively uncommon. Therefore, amnesia due to epilepsy can easily be misdiagnosed as dementia. The term 'transient epileptic amnesia (TEA)' was introduced in the early 1990s by Kapur, who highlighted that amnestic attacks caused by epilepsy can be similar to those occurring in 'transient global amnesia', but are distinguished by features brevity and recurrence. In 1998, Zeman et al. proposed diagnostic criteria for TEA.

  19. Luminous Extragalactic Transients

    NASA Astrophysics Data System (ADS)

    O'Brien, Paul; Jonker, Peter; Athena Explosive Transients Working Group

    2015-09-01

    The ESA Athena X-ray observatory mission will combine exceptionally high throughout with high spectral-energy resolution and will revolutionise many aspects of high-energy astrophysics. Many of the most powerful transient sources, including gamma-ray bursts and tidal disruptions events, are bright X-ray sources. Athena will be designed to have a fast-response capability permitting efficient observations of many transients. We will summarise the proposed capability of the mission and illustrate science programs to study transients ranging from the most distant GRBs to nuclear activity in nearby galaxies.

  20. Systemlieferant und OEM Hersteller für die Medizintechnik und Pharmabranche

    NASA Astrophysics Data System (ADS)

    Jakob, Thomas; Reichenberger, Robert

    Unter einem Original Equipment Manufacturer (OEM) versteht man einen Hersteller fertiger Komponenten oder Produkte, der diese in seinen eigenen Produktionsfabriken produziert, sie aber anschließend nicht selbst in den Handel bringt. Die Anforderungen an einen OEM für die Medizintechnik- und Pharmabranche sind weitaus komplexer und umfangreicher als in anderen Branchen. Diese zusätzlichen Anforderungen haben schließlich auch ihre Berechtigung, da es letztendlich immer um die Gesundheit und das Leben von Menschen geht. Ein OEM muss neben der heute immer stärker geforderten Flexibilität, Schnelligkeit und Wettbewerbsfähigkeit sämtliche für die Medizintechnik- und Pharmabranche erforderlichen Qualitäts- und Prozesssicherheitskriterien erfüllen. Entsprechende Nachweise sind durch regelmäßige Kunden- und Überwachungsaudits zu erbringen. Das Arbeitsumfeld eines OEM für die Medizintechnik- und Pharmabranche bezieht sich somit nicht nur auf die Herstellung der Produkte für seine Kunden, sondern auch auf die Einhaltung sämtlicher Normen, Sicherheitskriterien, regulatorischen Voraussetzungen und Gesetze die zur Herstellung der Produkte notwendig sind.

  1. PCR und Real-Time PCR

    NASA Astrophysics Data System (ADS)

    Konrad, Regina; Busch, Ulrich

    Die vielfältigen Anwendungsmöglichkeiten der Polymerasekettenreaktion (polymerase chain reaction, PCR) machen sie zu einer der wichtigsten und am häufigsten eingesetzten Methoden in der molekularbiologischen Forschung und Diagnostik. Für diese Technologie wurde der Erfinder der Methode, Kary Mullis, 1993 mit dem Nobelpreis ausgezeichnet. Die PCR erlaubt einen hochsensitiven und spezifischen in-vitro-Nachweis von Desoxyribonukleinsäuren (DNA), da im Zuge der Reaktion Sequenzabschnitte gezielt vermehrt werden. Innerhalb weniger Stunden können aus einem einzigen Zielmolekül 1012 identische Moleküle entstehen [1].

  2. Transient topographical amnesia.

    PubMed Central

    Stracciari, A; Lorusso, S; Pazzaglia, P

    1994-01-01

    Ten healthy middle aged or elderly women experienced isolated episodes of topographical amnesia without an obvious aetiology. It is likely a benign cognitive disorder, similar to transient global amnesia. PMID:7964826

  3. Transient Global Amnesia

    MedlinePlus

    ... global amnesia is a sudden, temporary episode of memory loss that can't be attributed to a ... know well. But that doesn't make your memory loss less disturbing. Fortunately, transient global amnesia is ...

  4. Transient Astrophysics Observatory (TAO)

    NASA Astrophysics Data System (ADS)

    Racusin, J. L.; TAO Team

    2016-10-01

    The Transient Astrophysics Observatory (TAO) is a NASA MidEx mission concept (formerly known as Lobster) designed to provide simultaneous wide-field gamma-ray, X-ray, and near-infrared observations of the sky.

  5. High energy transients

    NASA Technical Reports Server (NTRS)

    Woosley, S. E.

    1984-01-01

    A meeting was convened on the campus of the University of California at Santa Cruz during the two-week interval July 11 through July 22, 1983. Roughly 100 participants were chosen so as to give broad representation to all aspects of high energy transients. Ten morning review sessions were held in which invited speakers discussed the current status of observations and theory of the above subjects. Afternoon workshops were also held, usually more than one per day, to informally review various technical aspects of transients, confront shortcomings in theoretical models, and to propose productive courses for future research. Special attention was also given to the instrumentation used to study high energy transient and the characteristics and goals of a dedicated space mission to study transients in the next decade were determined. A listing of articles written by various members of the workshop is included.

  6. Transient multivariable sensor evaluation

    DOEpatents

    Vilim, Richard B.; Heifetz, Alexander

    2017-02-21

    A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.

  7. Gamma ray transients

    NASA Technical Reports Server (NTRS)

    Cline, Thomas L.

    1987-01-01

    The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

  8. Hochschule fur Film und Fernsehen (Babelsberg).

    ERIC Educational Resources Information Center

    Neumann, Roland

    1992-01-01

    Describes the Hochschule fur Film und Fernsehen, an institution of higher education for the study of film and television production in Babelsberg, Germany (formerly the German Democratic Republic). Discusses the major reorientations in the school caused by Germany's reunification. (SR)

  9. Satellitenbewegung, band III: Natiirliche und gesteuerte bewegung.

    NASA Astrophysics Data System (ADS)

    Jochim, E. F.

    2014-12-01

    Im dritten Band der Satellitenbewegung werden in fortlaufender Nummerierung einige für Untersuchungen der Bewegung der künstlichen Satelliten wichtige Grundlagen der Astrodynamik mit ausführlichen mathematischen Formelsystemen behandelt. Dazu zählen die unterschiedlichen Aspekte der Bewegung der natürlichen Himmelskörper, die Steuerung und Kontrolle von künstlichen Objekten, und insbesondere die für eine Satellitenbahnanalyse wichtigen physikalischen Beeinflussungen einer Satellitenbewegung. Mathematisch entscheidend ist die Wahl geeigneter Bahnparameter, die ein bestimmtes Bewegungsproblem widerspruchsfrei und singularitätenfrei zu behandeln gestatten. Für die Behandlung routinemäßiger Aufgabenstellungen der Satellitenbewegung, in erster Linie einer präzisen Bahnbestimmung und Bahnverbesserung, kann auf eine Fülle von lehrbuchartigen Monographien verwiesen werden, so dass diese Problematik in der vorliegenden Arbeit nur angedeutet werden soll.

  10. 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.

  11. Uniform National Discharge Standards (UNDS): Outreach

    EPA Pesticide Factsheets

    Describes the Federalism and Tribal consultation efforts related to the Uniform National Discharge Standards (UNDS) and links to copies of each presentation, both to state and local representatives, as well as federally-recognized tribes.

  12. Positionsbestimmung des Unternehmens: Interne und externe Analyse

    NASA Astrophysics Data System (ADS)

    Bergmann, Lars; Crespo, Isabel; Portmann, Stefan

    Die Initiierung und Lenkung von Maßnahmen zur integrierten Modernisierung zielen auf die Verbesserung der Wettbewerbsfähigkeit eines Unternehmens ab. Damit diese Maßnahmen zielgerichtet die Wettbewerbsfähigkeit verbessern können, ist Wissen über die bestehende Wettbewerbsfähigkeit sowie über die bestehenden Fähigkeiten eine zentrale Voraussetzung. Eine zielgerichtete Auswahl problemadäquater Maßnahmen zur Verbesserung der Wettbewerbsfähigkeit bedarf daher im Vorfeld einer Bewertung der aktuellen Situation des Unternehmens im Sinne einer Positionsbestimmung. Erst wenn die internen Stärken und Schwächen sowie die externen Chancen und Risiken identifiziert sind, kann ein ganzheitliches Bild von der Position eines Unternehmens in seiner Umwelt gewonnen werden. Auf Basis der Kenntnisse über die Position des Unternehmens können anschließend zielgerichtet Maßnahmen ausgewählt werden, die einen Beitrag zur Verbesserung der Wettbewerbsfähigkeit des Unternehmens haben. Damit kommt der Positionsbestimmung als initialer Schritt des Prozesses der strategischen Unternehmensplanung eine zentrale Bedeutung im Rahmen der integrierten Modernisierung zu. Erfolgt die Auswahl von Maßnahmen ohne eine vorherige Positionsbestimmung, also lediglich auf Basis drängender Probleme, so besteht die Gefahr einer unbedachten und nur auf das "hier und heute“ bezogenen Schwerpunktbildung ohne Berücksichtigung der mittel- und langfristigen Ziele des Unternehmens.

  13. Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Kulkarni, S.; Quimby, R.

    2010-12-01

    The Palomar Transient Factory (PTF) was designed to explicitly to chart the transient sky with a particular focus on events which lie in the nova-supernova gap. With its innovative two-telescope architecture it achieves both high cadence and large areal rate of coverage. PTF was commissioned during the summer of 2009. PTF is now finding an extragalactic transient every 20 minutes and a Galactic (strong) variable every 10 minutes. Spectroscopy undertaken at Keck and Palomar has allowed us: identify an emerging class of ultra-luminous supernovae, discover luminous red novae, undertake UV spectroscopy of Ia supernovae, discover supernovae powered by something other than Nickel-56, clarification of sub-classes of core collapse and thermo-nuclear explosions, map the systematics of core collapse supernovae, a trove of eclipsing binaries and many others.

  14. 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.

  15. Transient lingual papillitis.

    PubMed

    Kornerup, Ida M; Senye, Mireya; Peters, Edmund

    2016-01-01

    A case of recurrent, clinically innocuous, but painful papules involving the tongue dorsum of a 25-year-old man is presented. The lesions were interpreted to represent a transient lingual papillitis. This a poorly understood, but benign and self-limited condition involving the tongue fungiform papillae, which does not appear to be widely recognized.

  16. Transient familial hyperbilirubinemia

    MedlinePlus

    ... please enable JavaScript. Transient familial hyperbilirubinemia is a metabolic disorder that is passed down through families. Babies with ... M. Editorial team. Related MedlinePlus Health Topics Jaundice Metabolic Disorders Browse the Encyclopedia A.D.A.M., Inc. ...

  17. Lightning-Transient Recorder

    NASA Technical Reports Server (NTRS)

    Grumm, R. L.

    1984-01-01

    Battery-powered system operates for more than one year. Recorder digitizes and records up to 146 current samples at selected intervals during lightning stroke. System continues to store time tags of lightning strokes even if transient current memory is full.

  18. Photoacoustic transient imagery

    NASA Astrophysics Data System (ADS)

    Franceschi, J. L.; Marty-Dessus, D.; Severac, H.; Boucher, Jean-Marc; Bastie, A.

    1993-01-01

    A collimated laser diode associated with a small, short focal length objective lens produces a focused laser beam on the top of a sample glued onto a piezoelectric transducer. This laser beam is horizontally scanned on the surface and its intensity is modulated by a square wave using a TTL signal generator. This system induces acoustic waves in the sample. With a specially designed control circuitry, by combining this acoustic signal and the scanned laser beam, imaging of the subsurface is possible. The transient analysis developed is described and we show how to select cut-away views of the subsurface specimen with some applications in failure analysis of integrated circuits. We present the apparatus, the transient photoacoustic signal theory, and make a comparison between scanning photoacoustic (SPAM) and scanning electron acoustic microscopy (SEAM).

  19. Unusual CRTS Transient

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Mahabal, A.; Djorgovski, S. G.; Williams, R.; Graham, M. J.; Beshore, E. C.; Larson, S. M.; Christensen, E.; Christensen, E.; Beshore, E. C.; Larson, S. M.

    2008-10-01

    We have detected an optical transient of unknown nature in Catalina 0.7m Schmidt telescope images from 28 Sep 2008 UT. The object has the following parameters:

    CSS080928:160837+041626 2008-09-28 UT 02:50:49 RA 16:08:37.23 Dec 04:16:26.7 Mag 17.7 Type ?
    A possible uncataloged match to the transient is present in SDSS images with magnitude r~22.5.

  20. Synthesized light transients.

    PubMed

    Wirth, A; Hassan, M Th; Grguras, I; Gagnon, J; Moulet, A; Luu, T T; Pabst, S; Santra, R; Alahmed, Z A; Azzeer, A M; Yakovlev, V S; Pervak, V; Krausz, F; Goulielmakis, E

    2011-10-14

    Manipulation of electron dynamics calls for electromagnetic forces that can be confined to and controlled over sub-femtosecond time intervals. Tailored transients of light fields can provide these forces. We report on the generation of subcycle field transients spanning the infrared, visible, and ultraviolet frequency regimes with a 1.5-octave three-channel optical field synthesizer and their attosecond sampling. To demonstrate applicability, we field-ionized krypton atoms within a single wave crest and launched a valence-shell electron wavepacket with a well-defined initial phase. Half-cycle field excitation and attosecond probing revealed fine details of atomic-scale electron motion, such as the instantaneous rate of tunneling, the initial charge distribution of a valence-shell wavepacket, the attosecond dynamic shift (instantaneous ac Stark shift) of its energy levels, and its few-femtosecond coherent oscillations.

  1. Transient Pulse Monitor

    DTIC Science & Technology

    1988-05-20

    connection to the test solar array pannels . One radiated electromagnetic signal sensor will be placed on one of the solar array panels (Figures 6 and 7). The...22 02 Spacecraft, Charging , Discharge, Transient, Environment 19. ABSTRACT (Cmntnue on mromN ifesor AWMI endwtfr by blok numfber) SRI International is...6 2.1.2 Particle Interactions with Satellite Materials: Charging ........................ 6 2.1.3 Discharges and Their Effects on Systems

  2. Coherent Transient Systems Evaluation

    DTIC Science & Technology

    1993-06-17

    europium doped yttrium silicate in collaboration with IBM Almaden Research Center. Research into divalent ion doped crystals as photon gated materials...demonstration of the coherent transient continuous optical processor was performed in europium doped yttrium silicate. Though hyperfine split ground...materials. Research into divalent samarium doped into other hosts is incomplete and may produce better results. Preliminary measurements on Tm:KCl revealed

  3. Transient Detection Using Wavelets.

    DTIC Science & Technology

    1995-03-01

    signaL and transients are nonstationary. A new technique for the analysis of this type of signal, called the Wavelet Transform , was applied to artificial...and real signals. A brief theoretical comparison between the Short Time Fourier Transform and the Wavelet Transform is introduced A multisolution...analysis approach for implementing the transform was used. Computer code for the Discrete Wavelet Transform was implemented. Different types of wavelets to use as basis functions were evaluated. (KAR) P. 2

  4. Lunar transient phenomena

    NASA Astrophysics Data System (ADS)

    Cameron, W. S.

    1991-03-01

    Lunar transient phenomena (LTP) sightings are classified into five categories: brightenings, darkenings, reddish colorations, bluish colorations, and obscurations. There is evidence that the remaining LTP's are of lunar origin. A substantial number of sightings are independently confirmed. They have been recorded on film and spectrograms, as well as with photoelectric photometers and polarization equipment. It suggested that the LTP's may be gentle outgassings of less-than-volcanic proportions.

  5. ON DETECTING TRANSIENT PHENOMENA

    SciTech Connect

    Belanger, G.

    2013-08-10

    Transient phenomena are interesting and potentially highly revealing of details about the processes under observation and study that could otherwise go unnoticed. It is therefore important to maximize the sensitivity of the method used to identify such events. In this article, we present a general procedure based on the use of the likelihood function for identifying transients which is particularly suited for real-time applications because it requires no grouping or pre-processing of the data. The method makes use of all the information that is available in the data throughout the statistical decision-making process, and is suitable for a wide range of applications. Here we consider those most common in astrophysics, which involve searching for transient sources, events or features in images, time series, energy spectra, and power spectra, and demonstrate the use of the method in the case of a weak X-ray flare in a time series and a short-lived quasi-periodic oscillation in a power spectrum. We derive a fit statistic that is ideal for fitting arbitrarily shaped models to a power density distribution, which is of general interest in all applications involving periodogram analysis.

  6. Workshop on Radio Transients

    NASA Astrophysics Data System (ADS)

    Croft, Steve; Gaensler, Bryan

    2012-04-01

    abstract-type="normal">SummaryWe are entering a new era in the study of variable and transient radio sources. This workshop discussed the instruments and the strategies employed to study those sources, how they are identified and classified, how results from different surveys can be compared, and how radio observations tie in with those at other wavelengths. The emphasis was on learning what common ground there is between the plethora of on-going projects, how methods and code can be shared, and how best practices regarding survey strategy could be adopted. The workshop featured the four topics below. Each topic commenced with a fairly brief introductory talk, which then developed into discussion. By way of preparation, participants had been invited to upload and discuss one slide per topic to a wiki ahead of the workshop. 1. Telescopes, instrumentation and survey strategy. New radio facilities and on-going projects (including upgrades) are both studying the variability of the radio sky, and searching for transients. The discussion first centred on the status of those facilities, and on projects with a time-domain focus, both ongoing and planned, before turning to factors driving choices of instrumentation, such as phased array versus single pixel feeds, the field of view, spatial and time resolution, frequency and bandwidth, depth, area, and cadence of the surveys. 2. Detection, pipelines, and classification. The workshop debated (a) the factors that influence decisions to study variability in the (u,v) plane, in images, or in catalogues, (b) whether, and how much, pipeline code could potentially be shared between one project and another, and which software packages are best for different approaches, (c) how data are stored and later accessed, and (d) how transients and variables are defined and classified. 3. Statistics, interpretation, and synthesis. It then discussed how (i) the choice of facility and strategy and (ii) detection and classification schemes

  7. Transient transformation of plants.

    PubMed

    Jones, Huw D; Doherty, Angela; Sparks, Caroline A

    2009-01-01

    Transient expression in plants is a valuable tool for many aspects of functional genomics and promoter testing. It can be used both to over-express and to silence candidate genes. It is also scaleable and provides a viable alternative to microbial fermentation and animal cell culture for the production of recombinant proteins. It does not depend on chromosomal integration of heterologous DNA so is a relatively facile procedure and can lead to high levels of transgene expression. Recombinant DNA can be introduced into plant cells via physical methods, via Agrobacterium or via viral vectors.

  8. Thermal transient anemometer

    DOEpatents

    Bailey, J.L.; Vresk, J.

    1989-07-18

    A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

  9. Thermal transient anemometer

    DOEpatents

    Bailey, James L.; Vresk, Josip

    1989-01-01

    A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

  10. The Rapid Transient Surveyor

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Tonry, John; Wright, Shelley; Tully, R. Brent; Lu, Jessica R.; Takamiya, Marianne Y.; Hunter, Lisa

    2016-01-01

    The next decade of astronomy will be dominated by large area surveys (see the detailed discussion in the Astro-2010 Decadal survey and NRC's recent OIR System Report). Ground-based optical transient surveys, e.g., LSST, ZTF and ATLAS and space-based exoplanet, supernova, and lensing surveys such as TESS and WFIRST will join the Gaia all-sky astrometric survey in producing a flood of data that will enable leaps in our understanding of the universe. There is a critical need for further characterization of these discoveries through high angular resolution images, deeper images, spectra, or observations at different cadences or periods than the main surveys. Such follow-up characterization must be well matched to the particular surveys, and requires sufficient additional observing resources and time to cover the extensive number of targets.We describe plans for the Rapid Transient Surveyor (RTS), a permanently mounted, rapid-response, high-cadence facility for follow-up characterization of transient objects on the U. of Hawai'i 2.2-m telescope on Maunakea. RTS will comprise an improved robotic laser adaptive optics system, based on the prototype Robo-AO system (formerly at the Palomar 1.5-m and now at the Kitt Peak 2.2-m telescope), with simultaneous visible and near-infrared imagers as well as a near-infrared integral field spectrograph (R~100, λ = 850 - 1830 nm, 0.15″ spaxels, 8.7″×6.0″ FoV). RTS will achieve an acuity of ~0.07″ in visible wavelengths and < 0.16″ in the near infrared leading to an increase of the infrared point-source sensitivity against the sky background by a factor of ~9, crucial for efficient near-infrared spectroscopy.RTS will allow us to map the dark matter distribution in the z < 0.1 local universe with ten times better accuracy and precision than previous experiments. ATLAS will discover several thousand SNIae per year, measuring SNIa peak brightness, and decline rates, while RTS will measure reddening by dust, confirm SN type and

  11. Periodisches Hitzdrahtverfahren zur Messung von Wärme- und Temperaturleitfähigkeit von geringen Stoffmengen

    NASA Astrophysics Data System (ADS)

    Griesinger, A.; Spindler, K.; Hahne, E.

    Zusammenfassung Es wird ein Meßverfahren zur gleichzeitigen Bestimmung der Wärme- und der Temperaturleitfähigkeit von geringen Stoffmengen beschrieben. Neben Messungen an hochviskosen Flüssigkeiten eignet sich das Verfahren besonders für Messungen an Pulver-Schüttungen. Das Meßverfahren basiert auf dem transienten Hitzdraht-Verfahren. In einem dünnen Platindraht fließt ein sinusförmiger Wechselstrom, der den Draht periodisch erwärmt. Es entstehen thermische Wellen, die in die umgebende Probe eindringen. Die Amplitude und die Phasenlage der thermischen Wellen in der Probe hängen von der Temperaturleitfähigkeit a und der Wärmeleitfähigkeit λ der Probe ab. Die Temperaturschwingung in der Probe wird mit Hilfe des Platindrahtes gemessen, der gleichzeitig als Widerstandsthermometer eingesetzt wird. Meßwerte von Wasser und Glycerin zeigen eine gute Übereinstimmung mit Literaturwerten. Das Meßverfahren zeichnet sich dadurch aus, daß zur Bestimmung der Wärme- und Temperaturleitfähigkeit nur 13 ml einer Probe benötigt werden. Es werden Meßwerte einer Zeolith-Schüttung unter Wasserstoffbeladung dargestellt. A measuring procedure for the simultaneous determination of the thermal conductivity and thermal diffusivity of small quantities is described. The procedure is suited for high-viscous fluids and for powdery material. The measuring principle is based on the transient hot-wire method. A sinusoidal alternating current flows through a thin platinum wire and heats up the wire periodically. This results in thermal waves, which penetrate into the surrounding sample. The amplitude and the phase shift of the thermal waves depend on the thermal diffusivity ``a'' and the thermal conductivity ``λ'' of the sample. The temperature oscillation in the sample is measured by means of the platinum wire, which is simultaneously applied as a resistance thermometer. The values measured for water and glycerine correspond well to those given in literature. Results of the

  12. Calculating transient rates from surveys

    NASA Astrophysics Data System (ADS)

    Carbone, D.; van der Horst, A. J.; Wijers, R. A. M. J.; Rowlinson, A.

    2017-03-01

    We have developed a method to determine the transient surface density and transient rate for any given survey, using Monte Carlo simulations. This method allows us to determine the transient rate as a function of both the flux and the duration of the transients in the whole flux-duration plane rather than one or a few points as currently available methods do. It is applicable to every survey strategy that is monitoring the same part of the sky, regardless the instrument or wavelength of the survey, or the target sources. We have simulated both top-hat and Fast Rise Exponential Decay light curves, highlighting how the shape of the light curve might affect the detectability of transients. Another application for this method is to estimate the number of transients of a given kind that are expected to be detected by a survey, provided that their rate is known.

  13. The joy of transient chaos

    SciTech Connect

    Tél, Tamás

    2015-09-15

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  14. The Zwicky Transient Facility

    NASA Astrophysics Data System (ADS)

    Kulkarni, Shrinivas R.

    2016-01-01

    The Zwicky Transient Facility (ZTF) has been designed with a singular focus: a systematic exploration of the night sky at a magnitude level well suited for spectral classification and follow up with the existing class of 4-m to 10-m class telescopes. ZTF is the successor to the Palomar Transient Factory (PTF). The discovery engine for ZTF is a 47 square degree camera (realized through 16 e2V monolithic CCDs) that fills the entire focal plane of the 48-inch Oschin telescope of the Palomar Observatory. Single 30-s epoch sensitivity is about 20.5 in g and R bands. The Infarared Processing & Analysis Center (IPAC) is the data center for ZTF. ZTF is a public-private partnership with equal contributions from a consortium of world-wide partners and an NSF MSIP grant. Forty percent of ZTF time is set aside for two major community surveys: a 3-day cadence survey of high latitudes (to mimic LSST) and a time domain survey of the entire Northern Galactic plane. We expect first light in February 2017 and begin a 3-year survey starting summer of 2017. The first year will be spent on building up deep reference images of the sky (a must for transient surveys). During the second year IPAC will deliver near archival quality photometric products within 12 hours of observations. By comparison to reference images photometric alerts will be sent out. Year 3 will see the near real-time release of image differencing products. A Community Science Advisory Committee (CSAC), chaired by S. Ridgway (NOAO), has been set up to both advise the PI and to ensure that the US community's interests are well served. Astronomers interested in getting a head start on ZTF may wish to peruse the data releases from PTF. Young people (or young at heart) may wish to attend the annual summer school on PTF/ZTF (August, Caltech campus). The Principal Investigator (PI) for the project is S. Kulkarni and the Project Scientist is Eric Bellm.For further details please consult http://www.ptf.caltech.edu/ztf

  15. Ökologische Grundlagen und limitierende Faktoren der Renaturierung

    NASA Astrophysics Data System (ADS)

    Hölzel, N.; Rebele, F.; Rosenthal, G.; Eichberg, C.

    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).

  16. Modellgestützte Hybrid Systementwicklung - Modellierung und Optimierung

    NASA Astrophysics Data System (ADS)

    Huber, Thomas

    Im Bereich der Hybridfahrzeugentwicklung wird nach wie vor intensiv an Konzepten zur Verbrauchseinsparung und Reduzierung von Emissionen gearbeitet. Gleichzeitig sollen "Fahrspaß" und Komfort solcher Fahrzeuge verbessert werden. Für verschiedene Anwendungen sind unterschiedlichste Hybridkonzepte denkbar und sinnvoll. Trotz dieser Variantenvielfalt und den daraus resultierenden technischen Anforderungen sind die Kosten eines Hybridfahrzeugs zu minimieren, wobei ein wesentlicher Aspekt bei der Kostenreduzierung die Stückzahl ist. Bei der Entwicklung von Komponenten steht daher, neben den technischen Anforderungen, deren vielseitige Einsetzbarkeit im Vordergrund.

  17. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S. E-mail: hipolito@ceunes.ufes.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  18. DSN Transient Observatory

    NASA Astrophysics Data System (ADS)

    Kuiper, T. B. H.; Monroe, R. M.; White, L. A.; Miro, C. Garcia; Levin, S. M.; Majid, W. A.; Soriano, M.

    The Deep Space Network (DSN) Transient Observatory (DTO) is a signal processing facility that can monitor up to four DSN downlink bands for astronomically interesting signals. The monitoring is done commensally with reception of deep space mission telemetry. The initial signal processing is done with two CASPERa ROACH1 boards, each handling one or two baseband signals. Each ROACH1 has a 10 GBe interface with a GPU-equipped Debian Linux workstation for additional processing. The initial science programs include monitoring Mars for electrostatic discharges, radio spectral lines, searches for fast radio bursts and pulsars and SETI. The facility will be available to the scientific community through a peer review process.

  19. Unexpected transient effect.

    PubMed

    Chame, A; Villain, J

    2001-02-01

    When a grooved periodic profile cut in a crystalline surface relaxes through surface diffusion, flatter parts appear at the top and bottom in the transient state which precedes complete smoothing. This has been attributed to a tendency of successive steps of identical sign to draw closer to one another. This kind of kinetic interaction is a consequence of the finite value of the interatomic distance, and is present even if no interaction between steps is taken into account. We investigate this effect in a very simplified model, namely, a one-dimensional profile with alternating pairs of up and down steps, where no annihilation of steps is allowed. The quantitative effect is partly treated analytically.

  20. Transient heliosheath modulation

    NASA Astrophysics Data System (ADS)

    Quenby, J. J.; Webber, W. R.

    2015-10-01

    Voyager 1 has explored the solar wind-interstellar medium interaction region between the terminal shock and heliopause, following the intensity distribution of Galactic cosmic ray protons above 200 MeV energy. Before this component reached the expected galactic flux level at 121.7 au from the Sun, four episodes of rapid intensity change occurred with a behaviour similar to that found in Forbush Decreases in the inner Solar system, rather than that expected from a mechanism related to models for the long-term modulation found closer to the Sun. Because the mean solar wind flow is both expected and observed to be perpendicular to the radial direction close to the heliopause, an explanation is suggested in terms of transient radial flows related to possible heliopause boundary flapping. It is necessary that the radial flows are of the order either of the sound speed found for conditions downstream of the terminal shock or of the fluctuations found near the boundary by the Voyager 1 Low Energy Charged Particle detector and that the relevant cosmic ray diffusion perpendicular to the mean field is controlled by `slab' fluctuations accounting for about 20 per cent of the total power in the field variance. However, additional radial drift motion related to possible north to south gradients in the magnetic field may allow the inclusion of some diffusion according to the predictions of a theory based upon the presence of 2D turbulence. The required field gradients may arise due to field variation in the field carried by solar plasma flow deflected away from the solar equatorial plane. Modulation amounting to a total 30 per cent drop in galactic intensity requires explanation by a combination of transient effects.

  1. 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.

  2. Implantate und Verfahren in der Augenheilkunde

    NASA Astrophysics Data System (ADS)

    Neuhann, Tobias H.

    Das in der Medizin mit am häufigsten verwendete Implantat weltweit ist die Intraokulare Linse (IOL). Die Gründe hierfür sind vielschichtig: einmal haben die Operationstechniken in den letzten 30 Jahren eine wesentliche Steigerung an Gleichmäßigkeit, Erfolg und Effizienz erfahren, zum anderen verursachen die gestiegenen Anforderungen des Alltags in den Industrienationen und im Berufsleben den höheren Anspruch an das Sehvermögen. Ist die menschliche Linse Ursache für schlechtes Sehvermögen, besteht meist eine Trübung des Linsenproteins. Diese Trübung nennt wird Volksmund Grauer Star genannt, wissenschaftlich die Katarakt (cataracta). Es gibt unterschiedliche Formen wie angeborene (congenita) oder erworbene, traumatische, krankheitsoder altersbedingte Formen [45]. Wird die eingetrübte Linse nun mittels moderner Operationsverfahren entfernt, muss für Ersatz dieses lichtbrechenden Mediums gesorgt werden [2].

  3. Haptische Modellierung und Deformation einer Kugelzelle

    NASA Astrophysics Data System (ADS)

    Schippritt, Darius; Wiemann, Martin; Lipinski, Hans-Gerd

    Haptische Simulationsmodelle dienen in der Medizin in erster Linie dem Training operativer Eingriffe. Sie basieren zumeist auf physikalischen Gewebemodellen, welche eine sehr genaue Simulation der biomechanischen Eigenschaften des betreffenden Gewebes erlauben, aber gleichzeitig sehr rechenintensiv und damit zeitaufwändig in der Ausführung sind. Die menschliche Wahrnehmung kann allerdings auch eine ungenaue haptische Modellierung psychooptisch ausgleichen. Daher kann es sinnvoll sein, haptische Simulationen auch mit nicht vollständig physikalisch definierten Deformationsmodellen durchzuführen. Am Beispiel der haptischer Simulation einer in-vitro Fertilisation wird gezeigt, dass durch die Anwendung eines geometrischen Deformationsmodells eine künstliche Befruchtung unter realistischen experimentellen Bedingungen in Echtzeit haptisch simuliert und damit trainiert werden kann.

  4. The MWA Transients Survey (MWATS).

    NASA Astrophysics Data System (ADS)

    Bell, M.; Murphy, T.; Kaplan, D. L.; Croft, S. D.; Hancock, P.; Rowlinson, A.; Wayth, R.; Gaensler, B.; Hurley-Walker, N.; Offringa, A.; Loi, C.; Bannister, K.; Trott, C.; Marquart, J.

    2017-01-01

    We propose the continuation of the MWA transients survey to search for and monitor low frequency transient and variable radio sources in the southern sky. This proposal is aimed at commensally utilising data from the GLEAM-X (G0008) project in semester 2017-A. The aim of this commensal data acquisition is to commission long baseline observations for transient science. In particular this will involve studying the impact of the ionosphere on calibration and imaging, and developing the techniques needed to produce science quality data products. The proposed drift scans with LST locking (see G0008 proposal) are particularly exciting as we can test image subtraction for transient and variable identification. This survey is targeted at studying objects such as AGN (intrinsic and extrinsic variability), long duration synchrotron emitters, pulsars and transients of unknown origin. The maps generated from this survey will be analysed with the Variables and Slow Transients (VAST) detection pipeline. The motivation for this survey is as follows: (i) To obtain temporal data on an extremely large and robust sample of low frequency sources to explore and quantify both intrinsic and extrinsic variability; (ii) To search and find new classes of low frequency radio transients that previously remained undetected and obscured from multi-wavelength discovery; (iii) To place rigorous statistics on the occurrence of both transients and variables prior to the Australian SKA era.

  5. Summer 1993 Transient Student Report.

    ERIC Educational Resources Information Center

    Kent State Univ., Warren, OH. Office of Institutional Research.

    A study was conducted by the Trumbull Campus (TC) of Kent State University, in Ohio, to determine the motivations, objectives, and level of satisfaction of transient students, or students pursuing a degree at another institution but enrolled in courses at TC. Surveys were mailed to 50 transient students enrolled in summer 1993, with completed…

  6. Transient catalytic combustor model

    NASA Technical Reports Server (NTRS)

    Tien, J. S.

    1981-01-01

    A quasi-steady gas phase and thermally thin substrate model is used to analyze the transient behavior of catalytic monolith combustors in fuel lean operation. The combustor response delay is due to the substrate thermal inertia. Fast response is favored by thin substrate, short catalytic bed length, high combustor inlet and final temperatures, and small gas channel diameters. The calculated gas and substrate temperature time history at different axial positions provides an understanding of how the catalytic combustor responds to an upstream condition change. The computed results also suggest that the gas residence times in the catalytic bed in the after bed space are correlatable with the nondimensional combustor response time. The model also performs steady state combustion calculations; and the computed steady state emission characteristics show agreement with available experimental data in the range of parameters covered. A catalytic combustor design for automotive gas turbine engine which has reasonably fast response ( 1 second) and can satisfy the emission goals in an acceptable total combustor length is possible.

  7. MULTIMOMENT RADIO TRANSIENT DETECTION

    SciTech Connect

    Spitler, L. G.; Cordes, J. M.; Chatterjee, S.; Stone, J.

    2012-04-01

    We present a multimoment technique for signal classification and apply it to the detection of fast radio transients in incoherently dedispersed data. Specifically, we define a spectral modulation index in terms of the fractional variation in intensity across a spectrum. A signal whose intensity is distributed evenly across the entire band has a lower modulation index than a spectrum whose intensity is localized in a single channel. We are interested in broadband pulses and use the modulation index to excise narrowband radio frequency interference by applying a modulation index threshold above which candidate events are removed. The technique is tested both with simulations and using data from known sources of radio pulses (RRAT J1928+15 and giant pulses from the Crab pulsar). The method is generalized to coherent dedispersion, image cubes, and astrophysical narrowband signals that are steady in time. We suggest that the modulation index, along with other statistics using higher order moments, should be incorporated into signal detection pipelines to characterize and classify signals.

  8. Transient internal probe

    NASA Astrophysics Data System (ADS)

    Jarboe, Thomas R.; Mattick, Arthur T.

    1993-12-01

    The Transient Internal Probe (TIP) diagnostic is a novel method for probing the interior of hot magnetic fusion plasmas that are inaccessible with ordinary stationary probes. A small probe of magneto-optic (Verdet) material is fired through a plasma at speeds of several km/sec, illuminated by a laser beam. The beam's polarization is rotated in the probe by the local magnetic field and retroreflection back to a polarimetry detector allows determination of the B-field profile across the diameter of a plasma at a spatial resolution of better than 1-cm and an absolute B-field resolution of a few tens of Gauss. The principal components of a TIP diagnostic system were developed and tested. A two-stage light gas gun was constructed that accelerates 30-caliber projectiles to 3 km/sec, and methods were examined for stripping a lexan sabot from a probe prior to entry into a plasma. Probes of CdMnTe and FR-5 Verdet glass were fabricated, and a polarimetry system was constructed for resolving polarization to within 0.25 deg. The diagnostic was validated by measuring a static B-field with a moving (dropped) TIP probe, and finding agreement with Hall-probe measurements to within experimental accuracy (40 Gauss).

  9. Transient catalytic combustor model

    NASA Astrophysics Data System (ADS)

    Tien, J. S.

    1981-05-01

    A quasi-steady gas phase and thermally thin substrate model is used to analyze the transient behavior of catalytic monolith combustors in fuel lean operation. The combustor response delay is due to the substrate thermal inertia. Fast response is favored by thin substrate, short catalytic bed length, high combustor inlet and final temperatures, and small gas channel diameters. The calculated gas and substrate temperature time history at different axial positions provides an understanding of how the catalytic combustor responds to an upstream condition change. The computed results also suggest that the gas residence times in the catalytic bed in the after bed space are correlatable with the nondimensional combustor response time. The model also performs steady state combustion calculations; and the computed steady state emission characteristics show agreement with available experimental data in the range of parameters covered. A catalytic combustor design for automotive gas turbine engine which has reasonably fast response ( 1 second) and can satisfy the emission goals in an acceptable total combustor length is possible.

  10. Herstellung von Chitosan und einige Anwendungen

    NASA Astrophysics Data System (ADS)

    Struszczyk, Marcin Henryk

    2001-05-01

    1. Die Deacetylierung von crabshell - Chitosan führte gleichzeitig zu einem drastischen Abfall der mittleren viscosimetrischen Molmasse ( Mv), insbesondere wenn die Temperatur und die Konzentration an NaOH erhöht werden. Diese Parameter beeinflussten jedoch nicht den Grad der Deacetylierung (DD). Wichtig ist jedoch die Quelle des Ausgangsmaterials: Chitin aus Pandalus borealis ist ein guter Rohstoff für die Herstellung von Chitosan mit niedrigem DD und gleichzeitig hoher mittlerer Mv, während Krill-Chitin (Euphausia superba) ein gutes Ausgangsmaterial zur Herstellung von Chitosan mit hohem DD und niedrigem Mv ist. Chitosan, das aus Insekten (Calliphora erythrocephala), unter milden Bedingungen (Temperatur: 100°C, NaOH-Konzentration: 40 %, Zeit: 1-2h ) hergestellt wurde, hatte die gleichen Eigenschaften hinsichtlich DD und Mv wie das aus Krill hergestellte Chitosan. Der Bedarf an Zeit, Energie und NaOH ist für die Herstellung von Insekten-Chitosan geringer als für crabshell-Chitosan vergleichbare Resultaten für DD und Mv. 2. Chitosan wurde durch den Schimmelpilz Aspergillus fumigatus zu Chitooligomeren fermentiert. Die Ausbeute beträgt 25%. Die Chitooligomere wurden mit Hilfe von HPLC und MALDI-TOF-Massenspektrmetrie identifiziert. Die Fermentationsmischung fördert die Immunität von Pflanzen gegen Bakterien und Virusinfektion. Die Zunahme der Immunität schwankt jedoch je nach System Pflanze-Pathogen. Die Fermentation von Chitosan durch Aspergillus fumigatus könnte eine schnelle und billige Methode zur Herstellung von Chitooligomeren mit guter Reinheit und Ausbeute sein. Eine partiell aufgereinigte Fermentationsmischung dieser Art könnte in der Landwirtschaft als Pathogeninhibitor genutzt werden. Durch kontrollierte Fermentation, die Chitooligomere in definierter Zusammensetzung (d.h. definierter Verteilung des Depolymerisationsgrades) liefert, könnte man zu Mischungen kommen, die für die jeweilige Anwendung eine optimale Bioaktivität besitzen. 3

  11. Initiation of a coronal transient

    SciTech Connect

    Low, B.C.; Munro, R.H.; Fisher, R.R.

    1982-03-01

    This paper analyzes the coronal transient/eruptive prominence event of 1980 August 5 observed by the Mauna Loa experiment system. This event yielded data on the early development of the transient in the low corona between 1.2 R/sub sun/ and 2.2 R/sub sun/, information which was not available when earlier attempts were made to explain transient phenomena. The transient's initial appearance in the form of a rising density-depleted structure, prior to the eruption of the associated prominence, can be explained as an effect of magnetic buoyancy. The data indicate that this transient has a density depletion of 17% to 33% relative to an undisturbed corona which is approximately isothermal with a temperature of 1.5 x 10/sup 6/ K and a coronal density of 1.0 x 10/sup 9/ cm/sup -3/ at the base of the corona. The height versus base length relationship of the evolving transient resembles, remarkably well, the theoretical predictions obtained from a quasi-static model of a margnetically buoyant loop system. By matching this relationship with the theoretical model, we estimate the magnetic field at the base of the transient to be between 2 and 3 gauss. It is also shown that the initial, nearly constant speed of the top of the transient, 80 +- 20 km s/sup -1/, is consistent with a theoretical estimate calculated from the quasi-static model. These results suggest that some transients are not initiated impulsively, the initial stage of the development being driven by a quasi-static response to a slow change in magnetic field conditions at the base of the corona.

  12. The rapid transient surveyor

    NASA Astrophysics Data System (ADS)

    Baranec, C.; Lu, J. R.; Wright, S. A.; Tonry, J.; Tully, R. B.; Szapudi, I.; Takamiya, M.; Hunter, L.; Riddle, R.; Chen, S.; Chun, M.

    2016-07-01

    The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of 4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with an acuity of 0.07-0.10" across the entire visible spectrum (20% i'-band Strehl in median conditions) and <0.16" in the near infrared, and will detect companions at 0.5" at contrast ratio of 500. The system will include a high-efficiency prism integral field unit spectrograph: R = 70-140 over a total bandpass of 840-1830nm with an 8.7" by 6.0" field of view (0.15" spaxels). The AO correction boosts the infrared point-source sensitivity of the spectrograph against the sky background by a factor of seven for faint targets, giving the UH 2.2-m the H-band sensitivity of a 5.7-m telescope without AO.

  13. Transient Effects in Turbulence Modelling.

    DTIC Science & Technology

    1979-12-01

    field data are reported for recirculat- !I " " Ing water flows under steady-state and transient flow conditions in en 0I, Improved 1/15 scale FFTF ...15 scale FFTF outlet plenum test-cell. A dual-channel Laser Doppler Anemometer is used, and a unique method for performing transient measurements is...Description of Loop 26 3.1.2 Repeatable Flow Transient Generator (RFTG) 27 3.1.3 FFTF Test Cell 28 3.2 Laser Doppler Anemometer (LOA) 31 5 3.2.1 General

  14. CHARACTERIZATION OF TRANSIENT PUFF EMISSIONS ...

    EPA Pesticide Factsheets

    Symposium Paper Transient puff emissions were characterized from burning carpet charges that were fed to a pilotscale rotary kiln combustor to assess the potential impact on emissions of using post-consumer carpet as an alternative fuel in cement kilns.

  15. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  16. Transient Alerts in LSST

    NASA Astrophysics Data System (ADS)

    Kantor, J.

    During LSST observing, transient events will be detected and alerts generated at the LSST Archive Center at NCSA in Champaign-Illinois. As a very high rate of alerts is expected, approaching ˜ 10 million per night, we plan for VOEvent-compliant Distributor/Brokers (http://voevent.org) to be the primary end-points of the full LSST alert streams. End users will then use these Distributor/Brokers to classify and filter events on the stream for those fitting their science goals. These Distributor/Brokers are envisioned to be operated as a community service by third parties who will have signed MOUs with LSST. The exact identification of Distributor/Brokers to receive alerts will be determined as LSST approaches full operations and may change over time, but it is in our interest to identify and coordinate with them as early as possible. LSST will also operate a limited Distributor/Broker with a filtering capability at the Archive Center, to allow alerts to be sent directly to a limited number of entities that for some reason need to have a more direct connection to LSST. This might include, for example, observatories with significant follow-up capabilities whose observing may temporarily be more directly tied to LSST observing. It will let astronomers create simple filters that limit what alerts are ultimately forwarded to them. These user defined filters will be possible to specify using an SQL-like declarative language, or short snippets of (likely Python) code. We emphasize that this LSST-provided capability will be limited, and is not intended to satisfy the wide variety of use cases that a full-fledged public Event Distributor/Broker could. End users will not be able to subscribe to full, unfiltered, alert streams coming directly from LSST. In this session, we will discuss anticipated LSST data rates, and capabilities for alert processing and distribution/brokering. We will clarify what the LSST Observatory will provide versus what we anticipate will be a

  17. Catalina/Palomar Optical Transient

    NASA Astrophysics Data System (ADS)

    Ganeshalingam, M.; Griffith, C. V.; Filippenko, A. V.; Foley, R. J.

    2008-07-01

    Inspection of a CCD spectrum (range 330-1000 nm), obtained on July 7 UT with the 3-m Shane reflector (+ Kast spectrograph) at Lick Observatory, shows that the transient reported in ATel 1604 has a very blue, featureless continuum. This could be a very young Type II supernova (though at this time no clear hydrogen Balmer features are present), or some kind of Galactic transient. Further observations are encouraged.

  18. Grundlagen und Vollzug der amtlichen Lebensmittelkontrolle in der Schweiz

    NASA Astrophysics Data System (ADS)

    Hübner, Philipp; Spinner, Christoph

    In der Schweiz wird die Mehrheit der hoheitlichen Aufgaben von den 26 Kantonen, die zusammen die schweizerische Eidgenossenschaft bilden, autonom vollzogen. So liegt zum Beispiel die Kompetenz in den Bereichen Steuern, Gesundheit, Schulen oder Polizei grundsätzlich bei den Kantonen. Im Gegensatz dazu ist die Lebensmittelgesetzgebung national durch eidgenössische Erlasse harmonisiert. Die Vollzugsaufgaben liegen aber auch in diesem Bereich, abgesehen vom Vollzug an der Grenze und von einer nationalen Vollzugsaufsicht und Weisungsberechtigung, in kantonaler Kompetenz. Die Kantone können anhand kantonaler Erlasse das Bundesrecht präzisieren - insbesondere die organisatorischen Aspekte - und Regelungen im nicht harmonisierten Bereich treffen.

  19. Cohabitation Duration and Transient Domesticity.

    PubMed

    Golub, Andrew; Reid, Megan; Strickler, Jennifer; Dunlap, Eloise

    2013-01-01

    Research finds that many impoverished urban Black adults engage in a pattern of partnering and family formation involving a succession of short cohabitations yielding children, a paradigm referred to as transient domesticity. Researchers have identified socioeconomic status, cultural adaptations, and urbanicity as explanations for aspects of this pattern. We used longitudinal data from the 2001 Survey of Income and Program Participation to analyze variation in cohabitation and marriage duration by race/ethnicity, income, and urban residence. Proportional hazards regression indicated that separation risk is greater among couples that are cohabiting, below 200% of the federal poverty line, and Black but is not greater among urban dwellers. This provides empirical demographic evidence to support the emerging theory of transient domesticity and suggests that both socioeconomic status and race explain this pattern. We discuss the implications of these findings for understanding transient domesticity and make recommendations for using the Survey of Income and Program Participation to further study this family formation paradigm.

  20. Transient voltage oscillations in coils

    SciTech Connect

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated.

  1. Transient Faults in Computer Systems

    NASA Technical Reports Server (NTRS)

    Masson, Gerald M.

    1993-01-01

    A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

  2. Methodik und Qualität statistischer Erhebungen

    NASA Astrophysics Data System (ADS)

    Krug, Walter; Schmidt, Jürgen; Wiegert, Rolf

    Kapitel 8 wirft einen Blick hinter die Kulissen statistischer Arbeit und ihrer Methoden, insbesondere auch hinter die der amtlichen Statistik: Wie kommen die Myriaden von Zahlen zustande, die heute aus statistischen Quellenwerken aller Art und aus Datenbanken abgerufen werden können? Dabei wird deutlich, welche Schwierigkeiten bei Erhebungen, insbesondere bei Stichprobenerhebungen, zu überwinden sind, wie man Antwortverweigerer kooperativer stimmt, wie sich auch aus kleinen Stichproben auf intelligente Weise verlässliche Ergebnisse erzielen lassen und wie Großstichproben auf europäischer Ebene harmonisiert werden. Am Beispiel des Zensus 2011 wird gezeigt, wie sich eine Kombination von Stichproben und Registerauswertungen als Ersatz für eine Volkszählung nutzen lässt. Mitglieder der Deutschen Statistischen Gesellschaft waren daran kooperativ beteiligt.

  3. Studies of Transient Meteor Activity

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter M. M.

    2002-01-01

    Meteoroids bombard Earth's atmosphere daily, but occasionally meteor rates increase to unusual high levels when Earth crosses the relatively fresh ejecta of comets. These transient events in meteor activity provide clues about the whereabouts of Earth-threatening long-period comets, the mechanisms of large-grain dust ejection from comets, and the particle composition and size distribution of the cometary ejecta. Observations of these transient events provide important insight in natural processes that determine the large grain dust environment of comets, in natural phenomena that were prevalent during the time of the origin of life, and in processes that determine the hazard of civilizations to large impacts and of man-made satellites to the periodic blizzard of small meteoroids. In this proposal, three tasks form a coherent program aimed at elucidating various aspects of meteor outbursts, with special reference to planetary astronomy and astrobiology. Task 1 was a ground-based effort to observe periods of transient meteor activity. This includes: (1) stereoscopic imaging of meteors during transient meteor events for measurements of particle size distribution, meteoroid orbital dispersions and fluxes; and (2) technical support for Global-MS-Net, a network of amateur-operated automatic counting stations for meteor reflections from commercial VHF radio and TV broadcasting stations, keeping a 24h vigil on the level of meteor activity for the detection of new meteor streams. Task 2 consisted of ground-based and satellite born spectroscopic observations of meteors and meteor trains during transient meteor events for measurements of elemental composition, the presence of organic matter in the meteoroids, and products generated by the interaction of the meteoroid with the atmosphere. Task 3 was an airborne effort to explore the 2000 Leonid meteor outbursts, which are anticipated to be the most significant of transient meteor activity events in the remainder of the

  4. Konstruieren von Pkw-Karosserien: Grundlagen, Elemente und Baugruppen, Vorschriftenübersicht, Beispiele mit CATIA V4 und V5

    NASA Astrophysics Data System (ADS)

    Grabner, Jörg; Nothhaft, Richard

    Die Faszination, die vom Auto ausgeht, ist und bleibt ungebrochen. Entsprechend interessant ist es, sich vor dem Hintergrund konventioneller Konstruktionstechniken über die virtuelle Produktentwicklung von Pkw-Karosserien an modernen CAD-Arbeitsplätzen informieren zu können. Die Autoren führen in die Grundlagen ein und zeigen anhand von Beispielen und zahlreichen Abbildungen, wie mit dem System CATIA der Rohbau sowie die Ausstattung innen und au=C3=9Fen konstruiert werden. Darüber hinaus wird das so genannte "Package" an Beispielen beschrieben, also das Management und die Harmonisierung der Anforderungen an die Bauräume (z.

  5. Charting the Transient Sky: The Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Kulkarni, Shri

    2010-11-01

    Only about a hundred years ago astronomers came to recognize cosmic explosive events. What was once termed as Stella Nova are now divided into two major families, novae and supernovae (with real distinct classes in each). The variables and the explosions have been interesting in their own right and contributed richly to key problems in modern astrophysics: distances to galaxies and cosmography. The area of transient and variable stars is once again undergoing a renaissance due to wide field optical surveys. The Palomar Transient Factory (PTF) was designed to explicitly to chart the transient sky with a particular focus on events which lie in the nova-supernova gap.. With its innovative two-telescope architecture it achieves both high cadence and large areal rate of coverage. PTF was commissioned during the summer of 2009. PTF is now finding an extragalactic transient every 20 minutes and a Galactic (strong) variable every 10 minutes. Spectroscopy undertaken at Keck and Palomar has allowed us: identify an emerging class of ultra-luminous supernovae, discover luminous red novae, undertake UV spectroscopy of Ia supernovae, discover supernovae powered by something other than Nickel-56, clarification of sub-classes of core collapse and thermo-nuclear explosions, map the systematics of core collapse supernovae, a trove of eclipsing binaries and many others.

  6. Physik gestern und heute Von der Metallstange zum Hochenergielaser

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2002-05-01

    Im Mai 1752 wurde in Marly bei Paris auf Anregung des amerikanischen Forschers und Politikers Benjamin Franklin erstmals die elektrische Natur des Blitzes nachgewiesen. Damals beschrieb Franklin auch eine technische Vorrichtung, die als Schutz von Gebäuden vor Blitzschlägen dienen sollte: den Blitzableiter. Diese aus heutiger Sicht scheinbar triviale Vorrichtung wurde aber keineswegs unmittelbar akzeptiert. Und bis heute ist die Forschung zum Schutz von Einrichtungen vor Blitzschlägen nicht abgeschlossen.

  7. 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.

  8. Zahlen und Rechenvorgänge auf unterschiedlichen Abstraktionsniveaus

    NASA Astrophysics Data System (ADS)

    Rödler, Klaus

    "Das Verständnis geht langsam vor sich!" Diesen wichtigen Satz hörte ich bei einem Vortrag von Martin Lowsky. Auf die hier behandelte Fragestellung übertragen heißt das: Was eine Zahl ist und wie ich sie im Rechenvorgang einsetzen und interpretieren kann, das erschließt sich erst allmählich. Die Zahl des Rechenanfängers ist nicht dieselbe wie die des kompetenten Rechners und es ist nicht die Zahl des Lehrers oder der Lehrerin. Die Zahlen sind nur auf der Oberfläche der Worte und Zeichen gleich. Im Innern, im Verständnis, sind sie völlig verschieden! Ich glaube, dass die Missachtung dieser Divergenz dazu führt, dass manche Kinder in für den Lehrer und Lehrerin nicht nachvollziehbaren Routinen stecken bleiben, einfachste Informationen nicht wirklich integrieren. Die auf beiden Seiten wachsende Verunsicherung durch die nicht erkannte und daher nicht kommunizierbare Diskrepanz im inneren Zahlkonzept stört den allmählichen Aufbau strukturierter Zahlvorstellungen.

  9. Modifications of und rbcS in und Synechococcus sp. PCC7942 resulted in high CO sub 2 requiring mutants

    SciTech Connect

    Schwarz, R.; Liehman-Hurwitz, J.; Martinez, F.; Reinhold, L.; Kaplan, A. )

    1990-05-01

    High CO{sub 2} requiring mutants (HCR), capable of growing in the presence of kanamycin, were obtained following transformation with a construct containing {und nptII} in the coding region of rbcS (encoding for the small subunit (SS) of Rubisco). The apparent photosynthetic affinity for inorganic carbon was very low in mutant EK6 whereas in mutant JR12 it was only slightly lower than in high-CO{sub 2}-grown wild type. Southern analysis indicated double crossing over in the case of EK6. In mutant JR12 Southern analysis revealed some rearrangement and a deletion of a region downstream fro {und rbcS}. Western analysis demonstrated normal SS in JR12 but a larger (by about 3 kD) SS in EK6. Sequence analysis indicated that the latter was the result of fusion between {und rbcS} and the flanking region of {und nptII}.

  10. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-03-01

    We report the following transients found by the ATLAS survey (Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is robotically operational on Haleakala (see http://www.fallingstar.com).

  11. Metastable Packaging For Transient Electronics

    DTIC Science & Technology

    2014-09-01

    dated 16 Jan 09. Report contains color. 14. ABSTRACT Metastable polymeric materials were synthesized, formulated with additives and microcapsules ...photoacid generation, thermal activation, and mechanical rupture of acid-filled microcapsules -- were investigated. 15. SUBJECT TERMS transient...carbonate sulfone) (PVBCS)... 11  3.3  Thermal and Mechanical Triggered Transience of Electronic Devices via Embedded Microcapsules

  12. [Transient neonatal diabetes (author's transl)].

    PubMed

    de Ureta, A; Jiménez, M; Arroyos, A; Alonso, J A; Sánchez de León, L; Félix, V

    1980-07-01

    A case of transient diabetes "mellitus" in a newborn infant with secondary hypertonic dehydration is presented. Authors review the problematical ethiology of this rare disease and a commentary is made on the adequate control of their case with continuous endovenous infusion of insulin.

  13. Regelungen im Verkehr mit Lebensmitteln und Bedarfsgegenständen in Deutschland

    NASA Astrophysics Data System (ADS)

    Thomas, Gundula; Freund, Astrid; Gründig, Friedrich

    Im Zuge der Globalisierung von Produktion und Handel ändert sich auch der Charakter der Vorschriften im Lebensmittelrecht. Zunehmend treten internationale Rechtsbestimmungen, Abkommen, Standards und andere Normen an die Stelle nationaler Regelungen.

  14. VDI-Richtlinien - mit Technischen Regeln Wirtschaftlichkeit erhöhen und Standards setzen

    NASA Astrophysics Data System (ADS)

    Mandelartz, Johannes

    Der Verein Deutscher Ingenieure e.V. (VDI) ist ein gemeinnütziger, wirtschaftlich und politisch unabhängiger, technisch-wissenschaftlicher Verein von Ingenieuren und Naturwissenschaftlern. Mit über 137 000 persönlich zugeordneten Mitgliedern ist er eine der größten Ingenieur-Vereinigungen Europas und gilt in Deutschland als führender Sprecher der Technik und der Ingenieure. 1856 gegründet, hat er viele für die Technik wesentliche Entwicklungen in Gang gesetzt, so im Bereich der technischen Überwachung, der technischen Regelsetzung und Normung, der Arbeitsstudien, im gewerblichen Rechtsschutz und im Patentwesen. Seit seiner Gründung sieht es der VDI als seine Aufgabe, "das Zusammenwirken aller geistiger Kräfte der Technik im Bewusstsein ethischer Verantwortung zu fördern“ und die Lebensmöglichkeiten aller Menschen durch Entwicklung und sinnvoller Anwendung technischer Mittel zu verbessern.

  15. Exploring the Optical Transient Sky with the Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Rau, Arne; Kulkarni, Shrinivas R.; Law, Nicholas M.; Bloom, Joshua S.; Ciardi, David; Djorgovski, George S.; Fox, Derek B.; Gal-Yam, Avishay; Grillmair, Carl C.; Kasliwal, Mansi M.; Nugent, Peter E.; Ofek, Eran O.; Quimby, Robert M.; Reach, William T.; Shara, Michael; Bildsten, Lars; Cenko, S. Bradley; Drake, Andrew J.; Filippenko, Alexei V.; Helfand, David J.; Helou, George; Howell, D. Andrew; Poznanski, Dovi; Sullivan, Mark

    2009-12-01

    The Palomar Transient Factory (PTF) is a wide-field experiment designed to investigate the optical transient and variable sky on time scales from minutes to years. PTF uses the CFH12k mosaic camera, with a field of view of 7.9 deg2 and a plate scale of 1″ pixel-1, mounted on the Palomar Observatory 48 inch Samuel Oschin Telescope. The PTF operation strategy is devised to probe the existing gaps in the transient phase space and to search for theoretically predicted, but not yet detected, phenomena, such as fallback supernovae, macronovae,. Ia supernovae, and the orphan afterglows of gamma-ray bursts. PTF will also discover many new members of known source classes, from cataclysmic variables in their various avatars to supernovae and active galactic nuclei, and will provide important insights into understanding galactic dynamics (through RR Lyrae stars) and the solar system (asteroids and near-Earth objects). The lessons that can be learned from PTF will be essential for the preparation of future large synoptic sky surveys like the Large Synoptic Survey Telescope. In this article we present the scientific motivation for PTF and describe in detail the goals and expectations for this experiment.

  16. Verbesserte Ausbildung für neue Betriebsleiter und -ingenieure - eine wichtige Investition in die Zukunft

    NASA Astrophysics Data System (ADS)

    Franta, Oliver

    Bedingt durch die Globalisierung und die damit einhergehende Verschärfung des Wettbewerbs befinden sich die Produktionsbetriebe der chemischen Industrie in stetigem Wandel. Für Betriebsleiter und Betriebsingenieure werden damit Fähigkeiten wie Kostenmanagement, Sozial- und Organisationskompetenz, Führungsqualifikationen und unternehmerisches Handeln immer wichtiger. Neben den Anforderungsprofilen bei Neueinstellungen ist dies auch bei der Fortbildung zu berücksichtigen. Das Trainingsprogramm der Evonik Degussa wurde daher durch die Konzeption neuer Seminare und die Anpassung bestehender Weiterbildungsmaßnahmen weiterentwickelt. Neben Vorträgen und Fallbeispielen sind ebenfalls die Durchführung von Planspielen sowie das Kennenlernen eines Produktionsbetriebes einer anderen Organisationseinheit enthalten. Ziel ist es vor allem die unternehmerische Orientierung neuer Betriebsleiter und -ingenieure zu fördern, die Innovationsgeschwindigkeit zu erhöhen und durch Kenntnis und Nutzung bereits anderweitig entwickelter Lösungen und Methoden die Produktivität zu steigern. Die Produktionsmeister werden aufgrund der Bedeutung dieser Funktion für die Führung der Mitarbeiter und bei der Umsetzung von Veränderungsprojekten in das Ausbildungsprogramm einbezogen. Der Erfolg des Trainingsprogramms zeigt sich an den Teilnehmerzahlen und den ausgesprochen positiven Rückmeldungen.

  17. Nicolaus Copernicus Gesamtausgabe. Band VI/1. Documenta Copernicana: Briefe (Texte und Übersetzungen).

    NASA Astrophysics Data System (ADS)

    Kühne, A.

    Im Auftrage der Kommission für die Copernicus-Gesamtausgabe, herausgegeben von H. M. Nobis und M. Folkerts. Band VI/1 wurde bearbeitet von A. Kühne unter Mitarbeit von F. Boockmann und S. Kirschner und Verwendung der Vorarbeiten von H. M. Nobis.

  18. Spectroscopic Classifications of Optical Transients with SOAR

    NASA Astrophysics Data System (ADS)

    Hounsell, R. A.; Miller, J. A.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2016-06-01

    We report the following classifications of optical transients from spectroscopic observations with the Goodman spectrograph on the SOAR 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  19. Superresolution microscopy with transient binding.

    PubMed

    Molle, Julia; Raab, Mario; Holzmeister, Susanne; Schmitt-Monreal, Daniel; Grohmann, Dina; He, Zhike; Tinnefeld, Philip

    2016-06-01

    For single-molecule localization based superresolution, the concentration of fluorescent labels has to be thinned out. This is commonly achieved by photophysically or photochemically deactivating subsets of molecules. Alternatively, apparent switching of molecules can be achieved by transient binding of fluorescent labels. Here, a diffusing dye yields bright fluorescent spots when binding to the structure of interest. As the binding interaction is weak, the labeling is reversible and the dye ligand construct diffuses back into solution. This approach of achieving superresolution by transient binding (STB) is reviewed in this manuscript. Different realizations of STB are discussed and compared to other localization-based superresolution modalities. We propose the development of labeling strategies that will make STB a highly versatile tool for superresolution microscopy at highest resolution.

  20. Model refinement using transient response

    SciTech Connect

    Dohrmann, C.R.; Carne, T.G.

    1997-12-01

    A method is presented for estimating uncertain or unknown parameters in a mathematical model using measurements of transient response. The method is based on a least squares formulation in which the differences between the model and test-based responses are minimized. An application of the method is presented for a nonlinear structural dynamic system. The method is also applied to a model of the Department of Energy armored tractor trailer. For the subject problem, the transient response was generated by driving the vehicle over a bump of prescribed shape and size. Results from the analysis and inspection of the test data revealed that a linear model of the vehicle`s suspension is not adequate to accurately predict the response caused by the bump.

  1. Nonlinear Diffusion and Transient Osmosis

    NASA Astrophysics Data System (ADS)

    Akira, Igarashi; Lamberto, Rondoni; Antonio, Botrugno; Marco, Pizzi

    2011-08-01

    We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call “transient osmosis". We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes.

  2. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-03-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  3. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-09-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  4. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-10-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  5. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-08-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  6. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-06-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  7. 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.

  8. Spectral signatures of penumbral transients

    SciTech Connect

    Reardon, K.; Tritschler, A.

    2013-12-20

    In this work we investigate the properties of penumbral transients observed in the upper photospheric and chromospheric region above a sunspot penumbra using two-dimensional spectroscopic observations of the Ca II 854.21 nm line with a 5 s cadence. In our 30 minutes of observations, we identify several penumbral-micro jets (PMJs) with cotemporal observations from Dunn Solar Telescope/IBIS and Hinode/SOT. We find that the line profiles of these PMJ events show emission in the two wings of the line (±0.05 nm), but little modification of the line core. These are reminiscent of the line profiles of Ellerman bombs observed in plage and network regions. Furthermore, we find evidence that some PMJ events have a precursor phase starting 1 minute prior to the main brightening that might indicate initial heating of the plasma prior to an acoustic or bow shock event. With the IBIS data, we also find several other types of transient brightenings with timescales of less than 1 minute that are not clearly seen in the Hinode/SOT data. The spectral profiles and other characteristics of these events are significantly different from those of PMJs. The different appearances of all these transients are an indicator of the general complexity of the chromospheric magnetic field and underscore the highly dynamic behavior above sunspots. It also highlights the care that is needed in interpreting broadband filter images of chromospheric lines, which may conceal very different spectral profiles, and the underlying physical mechanisms at work.

  9. Transient virulence of emerging pathogens.

    PubMed

    Bolker, Benjamin M; Nanda, Arjun; Shah, Dharmini

    2010-05-06

    Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

  10. Herschel und die Zukunft der Fern-Infrarot-Astronomie

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik

    2015-06-01

    Schon lange ist die beobachtende Astronomie den engen Grenzen des optisch Sichbaren entwachsen und hat fast alle Bereiche des elektromagnetischen Spektrums für sich dienstbar gemacht. Im sogenannten nahen und mittleren Infrarot (Wellenlängen zwischen 1-30 μm) sowie im Millimeter- und Radio-Regime (Wellenlängen zwischen 1 mm und 10 m) ist die Erdatmosphäre relativ gut durchlässig für elektromagnetische Signale oder hat zumindest eine Vielzahl von spektral begrenzten Transmissionsfenstern, die astronomische Beobachtungen zumindest von höheren Bergen aus möglich machen. Allerdings ist das sogenannte Ferne Infrarot (FIR, 30-300 μm Wellenlänge) von der Erde aus fast völlig unzugänglich für astronomische Beobachtungen. Selbst für die besten Beobachtungsplätze der Erde bleibt die atmosphärische Transmission durch die immense Wasserdampf- Absorption auf ein absolutes Minimum beschränkt. Jedoch erlaubt uns das FIR Zugang zu Informationen, die sehr nützlich sind für die astrophysikalische Forschung und komplementär zu anderen Wellenlängen-Bereichen.

  11. Aufnahme, Analyse und Visualisierung von Bewegungen nativer Herzklappen in-vitro

    NASA Astrophysics Data System (ADS)

    Weiß, Oliver; Friedl, Sven; Kondruweit, Markus; Wittenberg, Thomas

    Die hohe Zahl an Transplantationen von Herzklappen und viele nötige Re-Operationen machen eine detaillierte Analyse der Strömungen und Klappenbewegungen klinisch interessant. Ein neuer Ansatz ist hierbei der Einsatz von Hochgeschwindigkeitskameras um Bewegungsabl äufe der Herzklappen beobachten und auswerten zu können. Die hohen Datenraten erfordern allerdings eine möglichst automatisierte Analyse und möglichst komprimierte Darstellung des Schwingungsverhaltens. In dieser Arbeit wird ein Ansatz vorgestellt, bei dem Bewegungen nativer Herzklappen in-vitro aufgenommen, analysiert und kompakt visualisiert werden.

  12. Searches for Fast Radio Transients

    NASA Astrophysics Data System (ADS)

    Cordes, J. M.; McLaughlin, M. A.

    2003-10-01

    We discuss optimal detection of fast radio transients from astrophysical objects while taking into account the effects of propagation through intervening ionized media, including dispersion, scattering, and scintillation. Our analysis applies to the giant-pulse phenomenon exhibited by some pulsars, for which we show examples, and to radio pulses from other astrophysical sources, such as prompt radio emission from gamma-ray burst sources and modulated signals from extraterrestrial civilizations. We estimate scintillation parameters for extragalactic sources that take into account scattering both in the host galaxy and in foreground Galactic plasma.

  13. Transient Idiopathic Primary Penoscrotal Edema

    PubMed Central

    Namir, Sody A; Trattner, Akiva

    2013-01-01

    We present the case of a male born prematurely at 32 weeks gestation by cesarean section following overt symptoms of maternal preeclampsia. He developed severe penoscrotal edema anew one month from birth. No remarkable exposure or trauma was identified. This unexplained swelling remained uniform till 4 months of age, while the penile edema resolved spontaneously. A small benign hydrocele remained unchanged, since onset of the edema and continued after the edema subsided. This is the first report of persistent, but transient penoscrotal edema resolving in a 3 months course, without any apparent explanation, a possible pathogenetic mechanism was suggested. PMID:24082210

  14. Observations of Solar Radio Transients

    NASA Astrophysics Data System (ADS)

    Paige, Giorla

    2011-05-01

    A low frequency radio telescope has been recently been constructed on the campus of the The College of New Jersey (TCNJ) and has begun conducting observations at 20MHz as part of NASA'a Radio Jove program. This instrument is capable of observations of solar radio emission including strong prompt radio emission associated with solar burst events. We will discuss solar observations conducted with this instrument as well as an effort to conduct coincident observations with the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  15. Preprocessing Techniques in Transient Analysis.

    DTIC Science & Technology

    1982-04-01

    with the problem of numerically determining the poles sl’s2’ .. associated with the Laplace trans- form of a given real transient y(t) = av exp~svt...97) D = " d d d ro rl ... rm (having do , dlT ,..**. d T as rows) can be factored in tne form 56 4) 98) D = B C where B is an (r+l)x (r+l)square...B,S have the same null space. In particular, exactly p of the diagonal elements si of S vanish, the corresponding p columns of B must vanish, and

  16. Light Echoes of Historic Transients

    NASA Astrophysics Data System (ADS)

    Rest, Armin; Sinnott, B.; Welch, D. L.; Prieto, J. L.; Bianco, F.

    2014-01-01

    Light echoes, light from a variable source scattered off dust, have been observed for over a century. The recent discovery of light echoes around centuries-old supernovae in the Milky Way and the Large Magellanic Cloud have allowed the spectroscopic characterization of these events, even without contemporaneous photometry and spectroscopy using modern instrumentation. Here we review the recent scientific advances using light echoes of ancient and historic transients, and focus on our latest work on SN 1987A's and Eta Carinae's light echoes.

  17. Hinderniserkennung und -verfolgung mit einer PMD-kamera im automobil

    NASA Astrophysics Data System (ADS)

    Schamm, Thomas; Vacek, Stefan; Natroshvilli, Koba; Marius Zöllner, J.; Dillmann, Rüdiger

    Die Detektion von Hindernissen vor dem Automobil ist eine Hauptanforderung an moderne Fahrerassistenzsysteme (FAS). In dieser Arbeit wird ein System vorgestellt, das mit Hilfe einer PMDKamera (Photomischdetektor) Hindernisse auf der Fahrspur erkennt und deren relevante Parameter bestimmt. Durch die PMD-Kamera werden zunächst 3D-Tiefenbilder der Fahrzeugumwelt generiert. Nach einem initialen Filterprozess werden im Tiefenbild mit Hilfe eines Bereichswachstumsverfahrens Hindernisse gesucht. Zur Stabilisierung des Verfahrens und zur Parameterberechnung wird ein Kaiman Filter eingesetzt. Das Ergebnis ist eine Liste aller Hindernisse im Fahrbereich des Automobils.

  18. Terror mit Atomwaffen: reale Gefahr? Nukleare und Radiologische Waffen

    NASA Astrophysics Data System (ADS)

    Harigel, Gert G.

    2006-01-01

    Können Terroristen sich nukleare Massenvernichtungswaffen beschaffen? Dazu müssten sie ausreichende Mengen an waffenfähigem, spaltbarem Material stehlen. Selbst der Bau einer primitiven Atombombe erfordert einen hohen technischen Aufwand und Spezialisten. Wahrscheinlicher ist deshalb der Diebstahl einer kleinen taktischen Kernwaffe. Alternativ könnten Terroristen sich radioaktives Material aus zivilen Quellen beschaffen und daraus eine Schmutzige Bombe bauen. Eine solche radiologische Waffe wäre keine echte Massenvernichtungswaffe, doch ihre psychologische Wirkung könnte stark sein. Das macht sie für Terroristen attraktiv, weswegen diese Gefahr ernst genommen werden muss.

  19. Reflexionseigenschaften von Windenergieanlagen im Funkfeld von Funknavigations- und Radarsystemen

    NASA Astrophysics Data System (ADS)

    Sandmann, S.; Divanbeigi, S.; Garbe, H.

    2015-11-01

    Die hier behandelte Untersuchung befasst sich mit den Störungen des elektrischen Feldes einer Doppler Very High Frequency Omnidirectional Radio Range Navigationsanlage (DVOR) in der Gegenwart von Windenergieanlagen (WEA). Hierfür wird die Feldstärke auf 25 konzentrischen Kreisbahnen, sog. Orbit Flights verschiedener Höhen und mit verschiedenen Radien rund um die DVOR-Anlage numerisch simuliert. Insbesondere werden die Einflüsse diverser Parameter der WEA wie deren Anzahl, Position, Rotorwinkel, Turmhöhe und Rotordurchmesser auf die Feldverteilung herausgestellt, sowie die Anwendbarkeit der Simulationsmethode Physical Optics (PO) durch Vergleich der Simulationsergebnisse mit denen der Multi Level Fast Multipol Method (MLFMM) untersucht.

  20. Transient effects in Herschel/PACS spectroscopy

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Jacobson, Jeffery D.; Appleton, Philip N.

    2016-10-01

    Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident flux with a certain delay. This generates transient effects on the resulting signal which can be important and last for up to an hour. Aims: The paper presents a study of the effects of transients on the detected signal and proposes methods to mitigate them especially in the case of the unchopped mode. Methods: Since transients can arise from a variety of causes, we classified them in three main categories: transients caused by sudden variations of the continuum due to the observational mode used; transients caused by cosmic ray impacts on the detectors; transients caused by a continuous smooth variation of the continuum during a wavelength scan. We propose a method to disentangle these effects and treat them separately. In particular, we show that a linear combination of three exponential functions is needed to fit the response variation of the detectors during a transient. An algorithm to detect, fit, and correct transient effects is presented. Results: The solution proposed to correct the signal for the effects of transients substantially improves the quality of the final reduction with respect to the standard methods used for archival reduction in the cases where transient effects are most pronounced. Conclusions: The programs developed to implement the corrections are offered through two new interactive data reduction pipelines in the latest releases of the Herschel Interactive Processing Environment.

  1. PRISMATIC CORE COUPLED TRANSIENT BENCHMARK

    SciTech Connect

    J. Ortensi; M.A. Pope; G. Strydom; R.S. Sen; M.D. DeHart; H.D. Gougar; C. Ellis; A. Baxter; V. Seker; T.J. Downar; K. Vierow; K. Ivanov

    2011-06-01

    The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.

  2. Postseismic relaxation and transient creep

    USGS Publications Warehouse

    Savage, J.C.; Svarc, J.L.; Yu, S.-B.

    2005-01-01

    Postseismic deformation has been observed in the epicentral area following the 1992 Landers (M = 7.3), 1999 Chi-Chi (M = 7.6), 1999 Hector Mine (M = 7.1), 2002 Denali (M = 7.9), 2003 San Simeon (M = 6.5), and 2004 Parkfield (M = 6.0) earthquakes. The observations consist of repeated GPS measurements of the position of one monument relative to another (separation ???100 km). The early observations (t < 0.1 year) are well fit by the function a' + c'log(t), where t is the time after the earthquake and a' and c' are constants chosen to fit the data. Because a log(t) time dependence is characteristic of transient (primary) creep, the early postseismic response may be governed by transient creep as Benioff proposed in 1951. That inference is provisional as the stress conditions prevailing in postseismic relaxation are not identical to the constant stress condition in creep experiments. The observed logarithmic time dependence includes no characteristic time that might aid in identifying the micromechanical cause.

  3. Special issue on transient plasmas

    NASA Astrophysics Data System (ADS)

    Bailey, James; Hoarty, David; Mancini, Roberto; Yoneda, Hitoki

    2015-11-01

    This special issue of Journal of Physics B: Atomic, Molecular and Optical Physics is dedicated to the "spectroscopy of transient plasmas" covering plasma conditions produced by a range of pulsed laboratory sources including short and long pulse lasers, pulsed power devices, and free electron lasers (FELs). The full range of plasma spectroscopy up to high energy bremsstrahlung radiation, including line broadening analysis for application to data recorded with the ChemCam instrument on the Mars Science Laboratory rover Curiosity, is covered. This issue is timely as advances in optical lasers and x-ray FELs (XFEL) are enabling transient plasma to be probed at higher energies and shorter durations than ever before. New XFEL facilities being commissioned in Europe and Asia are adding to those operating in the US and Japan and the ELI high power laser project in Europe, due to open this year, will provide short pulse lasers of unprecedented power. This special issue represents a snapshot of the theoretical and experimental research in dense plasmas, electron kinetics, laser-induced breakdown spectroscopy of low temperature plasmas, inertial confinement fusion and non-equilibrium atomic physics using spectroscopy to diagnose plasmas produced by optical lasers, XFELs and pulsed-power machines.

  4. Transient osteoporosis of the hip.

    PubMed

    Vernon, L F; Dooley, J C; Neidorf, D L

    1997-06-01

    Transient osteoporosis of the hip is an uncommon but probably underdiagnosed condition. There appears to be a predisposition for the condition in middle-aged males and in women in their third trimester of pregnancy. The etiology remains unclear, with theories that include vascular and neurologic disturbances. Clinical signs are usually pain in the hip area with functional disability of the affected limb. Plane film radiographs may be completely normal or show only minimal osteopenia. This report describes a 40-year-old male in whom transient osteoporosis of the hip was diagnosed. The patient's symptoms were initially interpreted as being due to sciatica; however, careful evaluation, further diagnostic work-up in the form of magnetic resonance imaging, and the clinical course of the disease ultimately led to the correct diagnosis. Resolution occurred gradually with non-steroidal anti-inflammatory drug therapy and rest. This case demonstrates the need for further evaluation of patients with hip-area pain who may have negative x-rays of the hip joint but continue to be symptomatic.

  5. The Zwicky Transient Facility Camera

    NASA Astrophysics Data System (ADS)

    Dekany, Richard; Smith, Roger M.; Belicki, Justin; Delacroix, Alexandre; Duggan, Gina; Feeney, Michael; Hale, David; Kaye, Stephen; Milburn, Jennifer; Murphy, Patrick; Porter, Michael; Reiley, Daniel J.; Riddle, Reed L.; Rodriguez, Hector; Bellm, Eric C.

    2016-08-01

    The Zwicky Transient Facility Camera (ZTFC) is a key element of the ZTF Observing System, the integrated system of optoelectromechanical instrumentation tasked to acquire the wide-field, high-cadence time-domain astronomical data at the heart of the Zwicky Transient Facility. The ZTFC consists of a compact cryostat with large vacuum window protecting a mosaic of 16 large, wafer-scale science CCDs and 4 smaller guide/focus CCDs, a sophisticated vacuum interface board which carries data as electrical signals out of the cryostat, an electromechanical window frame for securing externally inserted optical filter selections, and associated cryo-thermal/vacuum system support elements. The ZTFC provides an instantaneous 47 deg2 field of view, limited by primary mirror vignetting in its Schmidt telescope prime focus configuration. We report here on the design and performance of the ZTF CCD camera cryostat and report results from extensive Joule-Thompson cryocooler tests that may be of broad interest to the instrumentation community.

  6. Mass flow in loop type coronal transients

    NASA Technical Reports Server (NTRS)

    Anzer, U.; Poland, A. I.

    1979-01-01

    Coronal transients having characteristics of a well-defined loop structure are examined, particularly with respect to temporal changes in the density and mass per unit length along the loop over periods of several days after the initial eruption. Measurements of mass distributions as a function of time are presented for eight transients, and one particular transient with a fairly simple configuration is investigated in more detail. Theoretical calculations are combined with the masses and densities derived from the observations to obtain estimates of the material flow in the transients; this flow is modeled on the assumption that magnetic forces drive and confine the loop. The flow field is found to be diverging everywhere, indicating that the density decreases in time. It is inferred that the transient legs are approximately in hydrostatic equilibrium and that most of the mass of the transient is lost from the sun during the initial phase.

  7. Fast Transient Behavior of Thyristor Switches.

    DTIC Science & Technology

    1985-02-01

    FAST TRANSIENT BEHAVIOR OF THYRISTOR SWITCHES(U) TEXAS i/tl TECH UNIV LUBBOCK DEPT OF ELECTRICAL ENGINEERING PROTNOV FEB 85 RADC-TR-85-20...8217 , " , - ." .- ., .-, ..., .., . ., , ." ’ ’ , ’ , ., " " , ’ ., ., .., ..’ ..’ , .’ .. ., [ ." -.-.-, . ’ .J ,Z . ’ .’ , , . ,. C ; RADC-TR85-20 4 Final Technical Report February 1965 Lf) FAST TRANSIENT BEHAVIOR OF 4 ~THYRISTOR SWITCHES Texas Tech...Ctawaficaitonp FAST TRANSIENT BEHAVIOR OF THYRISTOR SWITCHES 12. PERSONAL AUTHOR(S)

  8. FERMI-LAT Observations of Galatic Transients

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2010-01-01

    This slide presentation reviews the use of the Large Area Telescope on the Fermi Observatory observations of Galactic Transients. LAT all-sky monitoring is producing spectacular results for the GeV transient sky: (1) New blazars and unidentified transients (2) Probing the jet of the Cygnus X-3 microquasar (3) Discovery of gamma rays from V407 Cygni nova (4) Fast high-energy gamma-ray flares from the Crab Nebula.

  9. Numerical Simulation of Heliospheric Transients Approaching Geospace

    DTIC Science & Technology

    2009-12-01

    12/15/08 – 12/14/09 Numerical Simulation of Heliospheric Transients Approaching Geospace Report by Dusan Odstrcil, University of Colorado...simulations of heliospheric transients approaching geospace . The project was supervised by Dr. Dusan Odstrcil at the University of Colorado (CU...plays a key role in the prediction accuracy of heliospheric transients approaching geospace . This report presents main results achieved within the

  10. Diorganostyrylzinndiorganophosphine und Ihre Tricarbonylnickelkomplexe (Diorganostyryltin Phosphines and its Tricarbonylnickel Complexes).

    DTIC Science & Technology

    1979-12-03

    Umkristallisieren aus Pentan/Benzol/Toluol gereinigt werden konnen; IVb zeigt bereits ab 0°C Polym erisationserschei- nungen. Vb und VIb werden als heligelbe...einem Rar.ger Engeneering M6ssbauer Spectrometer benutzt wurde. in C 6 D 6c) die Ha lbwertsbreiten wurden als glei~h vorausgesetzt , um dos Si gnal als

  11. Increasing Pragmatic Awareness: Die Vagheit der Sprache "und so"

    ERIC Educational Resources Information Center

    Overstreet, Maryann; Tran, Jennie; Zietze, Sylvia

    2006-01-01

    This article presents a description of some pragmatic expressions ("oder so," "und so," "oder wie") rarely found in textbooks, but common in everyday conversation. Though often treated as vague or superfluous, these expressions perform important functions in interpersonal communication. Focusing on these easily identifiable phrases can help…

  12. Denken in Wertschöpfung und Verschwendung

    NASA Astrophysics Data System (ADS)

    Bergmann, Lars; Lacker, Michael

    Eine Antwort auf die Frage welche Arbeitsschritte, Aktivitäten und Prozesse als wertschöpfend betrachtet werden können, erhält man durch die Überlegung, ob der Kunde bereit ist dafür zu zahlen. Kunden sind sicher bereit dafür zu zahlen, dass z.B. die Räder an ihrem neuen PKW sicher montiert sind. Die im Unternehmen notwendigen logistischen Prozesse, die die Räder zu ihrem Montageort transportieren, sind aus Sicht des Kunden dagegen mit keinem Wert verbunden. Insofern ist er nicht bereit dafür zu zahlen und sämtliche internen logistischen Aktivitäten sind entsprechend nicht wertschöpfend. Verschwendung bzw. nicht wertschöpfende Arbeit umfasst alle Aktivitäten, Tätigkeiten und Prozesse, die Zeit, Ressourcen und/oder Raum kosten, aber nicht zur Erfüllung der Kundenanforderungen beitragen. Verschwendung ist damit der Teil der Arbeit, für den der Kunde nicht zahlt, z.B. den internen Transport von Bauteilen zum Montageort.

  13. Transient Transport in Binary and Ternary Semiconductors.

    DTIC Science & Technology

    1986-02-27

    transport; Semiconductors, Microelectronics, Quantum transport , Boltzmann transport, Drift and diffusion, Gallium arsende, Aluminum gallium arsenide, Indium gallium arsenide, and Transient transport.

  14. Spectroscopic Classifications of Optical Transients with SOAR

    NASA Astrophysics Data System (ADS)

    Foley, R. J.; Hounsell, R. A.; Downing, S.; Pan, Y.-C.; Scolnic, D.; Jha, S. W.; Rest, A.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2015-07-01

    We report the following classifications of optical transients from spectroscopic observations with the Goodman spectrograph (wavelength range 3100 - 7100) on the Southern Astrophysical Research (SOAR) telescope.

  15. A Case of Transient Global Amnesia

    PubMed Central

    Mccroskey, Aidan L.; Deyerle, Branden A.

    2016-01-01

    Transient global amnesia is a clinical syndrome characterized by the sudden onset of anterograde amnesia, accompanied by repetitive questioning, sometimes with a retrograde component, lasting up to 24 hours, without compromise of other neurologic function. Neuroimaging after an acutetransient global amnesia event often shows transient perturbation of specific hippocampal circuits that are involved in memory processing. Critical clinical distinctions, such as between transient global amnesia and other forms of transient amnesic episodes, as well as important clues to the underlying pathophysiologies are herein reviewed. Finally, we discuss the role of hippocampal insufficiency in the neurobiology of delusions. PMID:27354927

  16. Adaptation to transient postural perturbations

    NASA Technical Reports Server (NTRS)

    Andres, Robert O.

    1992-01-01

    This research was first proposed in May, 1986, to focus on some of the problems encountered in the analysis of postural responses gathered from crewmembers. The ultimate driving force behind this line of research was the desire to treat, predict, or explain 'Space Adaptation Syndrome' (SAS) and hence circumvent any adverse effects of space motion sickness on crewmember performance. The aim of this project was to develop an easily implemented analysis of the transient responses to platform translation that can be elicited with a protocol designed to force sensorimotor reorganization, utilizing statistically reliable criterion measures. This report will present: (1) a summary of the activity that took place in each of the three funded years of the project; (2) discussion of experimental results and their implications for future research; and (3) a list of presentations and publications resulting from this project.

  17. X33 Transient Liftoff Analysis

    NASA Technical Reports Server (NTRS)

    Peck, Jeff; Brunty, Joseph

    2000-01-01

    The successful design of a launch vehicle requires the careful characterization of the various loads the structure will experience over its lifetime. Many of the most demanding load environments occur during the launch/ascent phase of a mission, typically defined as the point of engine start through engine cut off. One of the critical events during the launch phase is the liftoff event. This event imparts high loads on the vehicle due to transient events such as thrust build-up and vehicle release. This paper describes the theory and procedures used to calculate structural loads due to the liftoff event for the Lockheed-Martin X33 technology demonstrator vehicle. These procedures were developed at NASA's Marshall Space Flight Center and verified previously on other advanced launch system concepts and the Space Shuttle system.

  18. Catalina/Palomar Optical Transient

    NASA Astrophysics Data System (ADS)

    Mahabal, A.; Drake, A. J.; Djorgovski, S. G.; Williams, R.; Graham, M. J.; Beshore, E. C.; Larson, S. M.; Christensen, E.

    2008-07-01

    We have detected a brightening optical transient in Catalina and Palomar images starting from 23 Jun 2008 UT. The object has the following parameters:

    CSS080623:142206+334546 2008-06-23 UT 06:53:42 RA 14:22:05.77 Dec 33:45:46.1 Mag 18.3 Type SN?
    A very faint uncataloged source appears to be located near this position in SDSS images.

  19. Regulatory Analysis of Reactivity Transients

    SciTech Connect

    Beyer, Carl E.; Clifford, Paul M.; Geelhood, Kenneth J.; Voglewede, John C.

    2009-08-01

    This paper will describe modifications made to the FRAPCON-3 and FRAPTRAN fuel performance codes and models that impact reactivity initiated accident (RIA) analyses. The modified models include an upper bound empirical and best estimate release models for fast transients, and a revised fuel failure model that accounts for ductile and brittle failure. Because experimental data exists for discrete test conditions, the codes and models are used to interpolate and to some extent, to extrapolate these test conditions. An upper bound empirical model for release is used to establish new recommended release fractions for long-lived and short lived (radioactive) isotopes for RIA events in Regulatory Guide 1.183. A best estimate release model is used in FRAPTRAN 1.4 based on grain boundary gas concentrations from FRAPCON-3.4 to predict release for RIA events. Code and model predictions will be compared to failure and release data from RIA tests to demonstrate accuracy.

  20. Transient thermal stress recovery for structural models

    NASA Technical Reports Server (NTRS)

    Walls, William

    1992-01-01

    A method for computing transient thermal stress vectors from temperature vectors is described. The three step procedure involves the use of NASTRAN to generate an influence coefficient matrix which relates temperatures to stresses in the structural model. The transient thermal stresses are then recovered and sorted for maximum and minimum values. Verification data for the procedure is also provided.

  1. Transient thermoregulatory model with graphics output

    NASA Technical Reports Server (NTRS)

    Grounds, D. J.

    1974-01-01

    A user's guide is presented for the transient version of the thermoregulatory model. The model is designed to simulate the transient response of the human thermoregulatory system to thermal inputs. The model consists of 41 compartments over which the terms of the heat balance are computed. The control mechanisms which are identified are sweating, vaso-constriction and vasodilation.

  2. Transient age distributions in subsurface hydrologic systems

    NASA Astrophysics Data System (ADS)

    Engdahl, Nicholas B.; McCallum, James L.; Massoudieh, Arash

    2016-12-01

    Transient age distributions have received relatively little attention in the literature over the years compared to their steady-state counterparts. All natural systems are transient given enough time and it is becoming increasingly clear that understanding these effects and how they deviate from steady conditions will be important in the future. This article provides a high-level overview of the equations, techniques, and challenges encountered when considering transient age distributions. The age distribution represents the amount of water in a sample belonging to a particular age and the transient case implies that sampling the same location at two different times will result in different age distributions. These changes may be caused by transience in the boundary conditions, forcings (inputs), or physical changes in the geometry of the flow system. The governing equation for these problems contains separate dimensions for age and time and its solutions are more involved than the solute transport or steady-state age equations. Despite the complexity, many solutions have been derived for simplified, but transient, approximations and several numerical techniques exist for modeling more complex transient age distributions. This paper presents an overview of the existing solutions and contributes new examples of transient characteristic solutions and transient particle tracking simulations. The limitations for applying the techniques described herein are no longer theoretical or technological, but are now dominated by uncertainty in the physical properties of the flow systems and the lack of data for the historic inputs.

  3. Stability Test for Transient-Temperature Calculations

    NASA Technical Reports Server (NTRS)

    Campbell, W.

    1984-01-01

    Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

  4. Circuit protection devices for transient suppression

    NASA Technical Reports Server (NTRS)

    Childers, Richard

    1991-01-01

    The Electromer Corporation has developed a series of transient voltage suppression components based on a patented, specially formulated PolyClamp (trademark) material. PolyClamp components are a new class of transient voltage surge suppressors that extend the range of protection offered by transients protectors. The PolyClamp transient surge suppressors provide low capacitance, high energy capability, and packaging flexibility. A wide variety of applications can be protected. A tube and ferrule configuration was designed to be used with MIL/Aerospace style connectors and is designed to meet the applicable environmental, mechanical, and electrical requirements as defined by the United States and European defence standards performance requirements. Here, PolyClamp is compared with current transient surge suppressors. Typical performance and design are discussed.

  5. Galactic transients from the OGLE survey

    NASA Astrophysics Data System (ADS)

    Mroz, Przemek

    2016-07-01

    For many years, there were not any systematic, large-scale surveys for transients in the Milky Way and the Magellanic Clouds. This gap is being filled by discoveries from the OGLE survey, which has been regularly monitoring the densest sky regions (the Galactic bulge and disk, the Magellanic System) for over twenty years. The OGLE collection of Galactic transients contains several dozen classical novae and over a thousand other cataclysmic variables. I will tell how to select transients from billions of sources observed by the OGLE every night. I will show how the properties of classical novae depend on the underlying stellar population (and the star formation history). I will also discuss the preliminary results of the search for transients in the Milky Way disk from the OGLE-IV Galaxy Variability Survey. Finally, I will show some transients of yet unknown origin and present the OGLE-IV real time monitoring systems.

  6. Current status of the Explosive Transient Camera. [automated sky survey instument sensitive to optical transients

    NASA Technical Reports Server (NTRS)

    Vanderspek, Roland; Doty, John P.; Ricker, George R.

    1992-01-01

    The current configuration and performance of the Explosive Transient Camera (ETC), a wide-field sky monitor capable of detecting short-timescale optical transients, are briefly reviewed, as are plans for future improvements. The primary objective of the ETC is to detect an optical transient that is spatially and temporally coincident with a gamma-ray burster. However, the ETC is sensitive to all sources of short-timescale optical transients and will conduct a systematic survey of the night sky for all optical transients. Results of preliminary observations of the night sky conducted since January 1991 are summarized, and long-term variability searches with the ETC are discussed.

  7. Transient liquid phase ceramic bonding

    DOEpatents

    Glaeser, Andreas M.

    1994-01-01

    Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.

  8. Transient shocks beyond the heliopause

    DOE PAGES

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-30

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may bemore » interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.« less

  9. Transient shocks beyond the heliopause

    SciTech Connect

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-30

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.

  10. Transient spirals as superposed instabilities

    SciTech Connect

    Sellwood, J. A.; Carlberg, R. G. E-mail: carlberg@astro.utoronto.ca

    2014-04-20

    We present evidence that recurrent spiral activity, long manifested in simulations of disk galaxies, results from the superposition of a few transient spiral modes. Each mode lasts between 5 and 10 rotations at its corotation radius where its amplitude is greatest. The scattering of stars as each wave decays takes place over narrow ranges of angular momentum, causing abrupt changes to the impedance of the disk to subsequent traveling waves. Partial reflections of waves at these newly created features allows new standing-wave instabilities to appear that saturate and decay in their turn, scattering particles at new locations, creating a recurring cycle. The spiral activity causes the general level of random motion to rise, gradually decreasing the ability of the disk to support further activity unless the disk contains a dissipative gas component from which stars form on near-circular orbits. We also show that this interpretation is consistent with the behavior reported in other recent simulations with low-mass disks.

  11. Monitoring of Transient Lunar Phenomena

    NASA Astrophysics Data System (ADS)

    Barker, Timothy; Farber, Ryan; Ahrendts, Gary

    2014-06-01

    Transient Lunar Phenomena (TLP’s) are described as short-lived changes in the brightness of areas on the face of the Moon. TLP research is characterized by the inability to substantiate, reproduce, and verify findings. Our current research includes the analysis of lunar images taken with two Santa Barbara Instrument Group (SBIG) ST8-E CCD cameras mounted on two 0.36m Celestron telescopes. On one telescope, we are using a sodium filter, and on the other an H-alpha filter, imaging approximately one-third of the lunar surface. We are focusing on two regions: Hyginus and Ina. Ina is of particular interest because it shows evidence of recent activity (Schultz, P., Staid, M., Pieters, C. Nature, Volume 444, Issue 7116, pp. 184-186, 2006). A total of over 50,000 images have been obtained over approximately 35 nights and visually analyzed to search for changes. As of March, 2014, no evidence of TLPs has been found. We are currently developing a Matlab program to do image analysis to detect TLPs that might not be apparent by visual inspection alone.

  12. Clinical applications of transient elastography

    PubMed Central

    Jung, Kyu Sik

    2012-01-01

    Chronic liver disease represents a major public health problem, accounting for significant morbidity and mortality worldwide. As prognosis and management depend mainly on the amount and progression of liver fibrosis, accurate quantification of liver fibrosis is essential for therapeutic decision-making and follow-up of chronic liver diseases. Even though liver biopsy is the gold standard for evaluation of liver fibrosis, non-invasive methods that could substitute for invasive procedures have been investigated during past decades. Transient elastography (TE, FibroScan®) is a novel non-invasive method for assessment of liver fibrosis with chronic liver disease. TE can be performed in the outpatient clinic with immediate results and excellent reproducibility. Its diagnostic accuracy for assessment of liver fibrosis has been demonstrated in patients with chronic viral hepatitis; as a result, unnecessary liver biopsy could be avoided in some patients. Moreover, due to its excellent patient acceptance, TE could be used for monitoring disease progression or predicting development of liver-related complications. This review aims at discussing the usefulness of TE in clinical practice. PMID:22893866

  13. Transient effects in laser cooling

    SciTech Connect

    Padua, S.; Xie, C.; Gupta, R.; Batelaan, H.; Bergeman, T.; Metcalf, H.

    1993-05-01

    Transient laser cooling (TLC) can produce cooling and heating, but often with the opposite detuning from that found in steady state. In TLC the time scale is set by the optical pumping (OP) rate to a state not coupled by the laser field. The combination of such OP processes and the conservative light shift potential U{sub o}sin{sup 2}kz leads to TLC. The average PE of atoms entering a standing wave is U{sub o}/2. They experience the optical force until undergoing OP to an uncoupled state, which is more likely to happen at high light intensity, near an antinode. For {delta} > 0 this means higher PE and thus lower KE, and conversely for {delta} < 0. In TLC there is no final {open_quotes}temperature{close_quotes} resulting from competition between a damping force and diffusive heating. Instead the changes in KE are bounded by U{sub o} so that the signal widths decrease with intensity. This can result in sub-Doppler widths. We have made two independent theoretical studies of these experiments. In a semiclassical calculation we evolve the motion for a calculated OP time and calculate the velocity distribution. We have also performed fully quantum mechanical calculations of the motion of atoms in the standing wave whose basis set consists of product states of internal and external atomic coordinates.

  14. POET: POlarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; McConnell, M. L.; Bloser, P.; Legere, J.; Macri, J.; Ryan, J.; Barthelmy, S.; Angelini, L.; Sakamoto, T.; Black, J. K.; Hartmann, D. H.; Kaaret, P.; Zhang, B.; Ioka, K.; Nakamura, T.; Toma, K.; Yamazaki, R.; Wu, X.

    2008-01-01

    POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. POET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  15. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    The figure shows a prototype of a relatively inexpensive electronic monitoring apparatus that measures and records selected parameters of lightning-induced transient voltages on communication and power cables. The selected parameters, listed below, are those most relevant to the ability of lightning-induced transients to damage electronic equipment. This apparatus bridges a gap between some traditional transient-voltage recorders that record complete waveforms and other traditional transient-voltage recorders that record only peak values: By recording the most relevant parameters and only those parameters this apparatus yields more useful information than does a traditional peak-value (only) recorder while imposing much smaller data-storage and data-transmission burdens than does a traditional complete-waveform recorder. Also, relative to a complete-waveform recorder, this apparatus is more reliable and can be built at lower cost because it contains fewer electronic components. The transients generated by sources other than lightning tend to have frequency components well below 1 MHz. Most commercial transient recorders can detect and record such transients, but cannot respond rapidly enough for recording lightning-induced transient voltage peaks, which can rise from 10 to 90 percent of maximum amplitude in a fraction of a microsecond. Moreover, commercial transient recorders cannot rearm themselves rapidly enough to respond to the multiple transients that occur within milliseconds of each other on some lightning strikes. One transient recorder, designed for Kennedy Space Center earlier [ Fast Transient-Voltage Recorder (KSC- 11991), NASA Tech Briefs, Vol. 23, No. 10, page 6a (October 1999)], is capable of sampling transient voltages at peak values up to 50 V in four channels at a rate of 20 MHz. That recorder contains a trigger circuit that continuously compares the amplitudes of the signals on four channels to a preset triggering threshold. When a trigger signal

  16. Transient Effects and Disturbed Conditions

    NASA Astrophysics Data System (ADS)

    Wibberenz, G.; Le Roux, J. A.; Potgieter, M. S.; Bieber, J. W.

    1998-01-01

    In the present phase of the solar cycle no big transients leading to strong modulation had been observed after 1991. Apart from a few minor disturbances cosmic rays were still recovering to a new intensity maximum. It was suggested, therefore, that existing literature from previous cycles should be critically reviewed. The scene was set by the introductory papers on - phenomenology of cosmic ray modulation in successive solar cycles throughout the heliosphere, - the present state of models for long term modulation and their shortcomings, - the relation between cosmic ray variations and the magnitude of the interplanetary magnetic field (the CR-B-relation), - charge dependent effects. In the discussions, the study of propagating diffusive disturbances and the CR-B-relation played a central role. The difference was stressed between isolated transient disturbances in the inner solar system (Forbush decreases), and the long lasting, step-like decreases caused by merged interaction regions in the outer heliosphere. The recovery rates following the step-like decreases vary with the phase in the 22-year solar cycle. In some cases this requires a modification of existing drift models. In the outer heliosphere, the CR-B-relation leads to the result Κ alpha 1/Β between the diffusion coefficient Κ and the field magnitude Β. This simple result is a challenge for theoreticians to derive the perpendicular diffusion coefficient fromfirst principles. The three articles in this report essentially follow the list of open points and arguments just presented. The article "Observations and Simple Models" is organised around the model of a propagating diffusive barrier, its application to Forbush effects in the inner heliosphere and to decreases caused by merged interaction regions in the outer heliosphere. Acomparison of observed Forbush decreases with model predictions requires a careful separation of the two steps related to the turbulent region behind the shock front and the

  17. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    EPA Science Inventory

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  18. Fermi-LAT Observations of Galactic Transients

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2011-01-01

    This slide presentation reviews the observations of Galactic transients by the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope. The LAT is producing spectacular results for the GeV transient sky, some of which are shown and reviewed. Some of the results in the GeV range that are discussed in this presentation are: (1) New blazars and unidentified transients (2) the jet of the Cygnus X-3 microquasar (3) gamma rays from V407 Cygni nova (4) Fast high-energy gamma-ray flares from the Crab Nebula

  19. Transients in a circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  20. Modeling of Transient Heat Pipe Operation

    NASA Technical Reports Server (NTRS)

    Colwell, G. T.; Hartley, J. G.

    1984-01-01

    The major goal of this project is to develop mathematical models of heat pipes which can be used to predict transient behavior under normal and adverse conditions. The models and solution techniques are to be formulated so that they can be incorporated into existing NASA structural design codes. The major parameters of interest are heat flux distribution, temperature distribution, working fluid pressure distribution, fluid and containment thermal and mechanical properties and geometry. Normal transient operation is taken to be operating conditions where the capillary structure remains fully wetted. Adverse transient operation occurs when drying, re-wetting, choking, non-continuum flow, thawing, freezing, etc., occur in the internal heat pipe working fluid.

  1. Transient epileptic amnesia: a concise review.

    PubMed

    Asadi-Pooya, Ali A

    2014-02-01

    Transient epileptic amnesia (TEA) is a distinctive syndrome and comprises episodic transient amnesia with an epileptic basis, without impairment of other aspects of cognitive function. Additional interictal memory deficits are common in TEA. An epileptic origin, after other etiologies have been excluded, should be considered and carefully investigated in patients complaining of isolated memory disturbances, particularly with recurrent short-lasting amnesic attacks. In all suspected cases of epilepsy, a detailed clinical history is of paramount importance, but ancillary tests including EEG and MRI could be very helpful. Transient epileptic amnesia is typically a benign and treatable condition. Future studies should investigate the exact mechanism(s) of this unique syndrome.

  2. Single-Event Transients in Voltage Regulators

    NASA Technical Reports Server (NTRS)

    Johnston, Allan H.; Miyahira, Tetsuo F.; Irom, F.; Laird, Jamie S.

    2006-01-01

    Single-event transients are investigated for two voltage regulator circuits that are widely used in space. A circuit-level model is developed that can be used to determine how transients are affected by different circuit application conditions. Internal protection circuits-which are affected by load as well as internal thermal effects-can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. Although conventional output transients can be reduced by adding load capacitance, that approach is ineffective for dropouts from protection circuitry.

  3. Kraft-Wärmekopplung und Blockheiz-Kraftwerke BHKW

    NASA Astrophysics Data System (ADS)

    Zahoransky, Richard; Allelein, Hans-Josef; Bollin, Elmar; Oehler, Helmut; Schelling, Udo

    Die thermischen Wirkungsgrade von Kraftwerken zur Stromerzeugung sind relativ gering. Beispielsweise erreichen moderne Kohlekraftwerke heute bis etwa 45 %, Gasturbinen maximal 40 % und Diesel-Motoren nicht über 50 %. Kombinations-Kraftwerke, Gas- und Dampfturbinen-Prozesse können an die 60 % thermischer Wirkungsgrad bei der Umwandlung der zugeführten Wärme in mechanische bzw. elektrische Energie erzielen. Ein ähnlich hoher Wert wird in Zukunft von den Brennstoffzellen erwartet. Der nicht in Arbeit umgewandelte Anteil der zugeführten Wärme fällt als Abwärme an und geht ungenutzt in die Umgebung. Ein Teil dieser Abwärme lässt sich durch entsprechende Installationen bei allen Kraftwerksprozessen zur Wassererwärmung oder zur Dampferzeugung für industrielle Zwecke nutzen. Für Heizzwecke genügt eine Temperatur der Abwärme von 60 %C bis 80 %C, während die Erzeugung von Industriedampf deutlich höhere Temperaturen voraussetzt.

  4. TRACE spectroscopic classification of optical transients

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Childress, M.; Sullivan, M.; Kotak, R.; Maguire, K.; Young, D.; Smith, K. W.; Smartt, S. J.; Mazzali, P.; Tonry, J.; Chambers, K.; Stalder, B.; Denneau, L.; Heinze, A.; Huber, M.; Weiland, H.; Rest, A.

    2017-03-01

    TRACE, the Transient RApid Classification Experiment (PI: Inserra, ATel #10055), reports the following supernova classifications. The targets were supplied by ATLAS survey, see Tonry et al. (2011, PASP, 123, 58) and Tonry et al. (ATel #8680).

  5. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    NASA Technical Reports Server (NTRS)

    Justak, John F.

    1992-01-01

    Proposed bearing assembly for shaft of high-speed turbopump includes both hydrostatic and rolling-element bearings. Rolling-element bearing unloaded at high speed by centrifugal expansion of outer race and transient retainer.

  6. TRACE spectroscopic classification of optical transient

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Childress, M.; Sullivan, M.; Kotak, R.; Maguire, K.; Young, D.; Smith, K. W.; Smartt, S. J.; Mazzali, P.; Tonry, J.; Chambers, K.; Stalder, B.; Huber, M.; Denneau, L.; Heinze, A.; Weiland, H.; Rest, A.

    2017-02-01

    TRACE, the Transient RApid Classification Experiment (PI: Inserra), reports the following supernova classification. The target was supplied by ATLAS survey, see Tonry et al. (2011, PASP, 123, 58) and Tonry et al. (ATel #8680).

  7. TRACE spectroscopic classification of optical transient

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Childress, M.; Sullivan, M.; Kotak, R.; Maguire, K.; Young, D.; Smith, K. W.; Smartt, S. J.; Mazzali, P.; Tonry, J.; Chambers, K.; Stalder, B.; Denneau, L.; Heinze, A.; Huber, M.; Weiland, H.; Rest, A.

    2017-02-01

    TRACE, the Transient RApid Classification Experiment (PI: Inserra, ATel #10055), reports the following supernova classification. The target was supplied by ATLAS survey, see Tonry et al. (2011, PASP, 123, 58) and Tonry et al. (ATel #8680).

  8. Transient effects on stimulated Brillouin scattering

    SciTech Connect

    Faris, G.W.; Dyer, M.J.; Hickman, A.P. )

    1992-08-01

    We present a detailed comparison of theory and experiment for transient stimulated Brillouin scattering for a pump pulse with Gaussian temporal profile. A new approach for measuring Brillouin linewidths is demonstrated, and an unexplained asymmetry is observed.

  9. Boiling water reactor licensing basis transient

    SciTech Connect

    Cheng, H. S.; Lu, M. S.; Shier, W. G.; Diamond, D. J.; Levine, M. M.; Odar, F.

    1980-01-01

    An analysis is presented of the licensing basis transient for a boiling water reactor where a turbine trip occurs without steam bypass. The analysis was performed by means of the two-dimensional (R,Z) core dynamics code BNL-TWIGL in conjunction with the system transient code RELAP-3B. Two plant models were used and produced similar results for the analysis of the Peach Bottom turbine trip tests. The models differed in the representation of the steam separator. The analysis of the licensing basis transient produced somewhat different results. The results of sensitivity studies to help explain the differences are presented as well as an analysis of the licensing basis transient with recirculation pump trip. 2 refs., 17 figs., 1 tab.

  10. Wavelet Signal Processing for Transient Feature Extraction

    DTIC Science & Technology

    1992-03-15

    Research was conducted to evaluate the feasibility of applying Wavelets and Wavelet Transform methods to transient signal feature extraction problems... Wavelet transform techniques were developed to extract low dimensional feature data that allowed a simple classification scheme to easily separate

  11. Transient loads analysis for space flight applications

    NASA Technical Reports Server (NTRS)

    Thampi, S. K.; Vidyasagar, N. S.; Ganesan, N.

    1992-01-01

    A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example.

  12. On transient rheology and glacial isostasy

    NASA Technical Reports Server (NTRS)

    Yuen, David A.; Sabadini, Roberto C. A.; Gasperini, Paolo; Boschi, Enzo

    1986-01-01

    The effect of transient creep on the inference of long-term mantle viscosity is investigated using theoretical predictions from self-gravitating, layered earth models with Maxwell, Burgers' body, and standard linear solid rheologies. The interaction between transient and steady-state rheologies is studied. The responses of the standard linear solid and Burgers' body models to transient creep in the entire mantle, and of the Burgers' body and Maxwell models to creep in the lower mantle are described. The models' responses are examined in terms of the surface displacement, free air gravity anomaly, wander of the rotation pole, and the secular variation of the degree 2 zonal coefficient of the earth's gravitational potential field. The data reveal that transient creep cannot operate throughout the entire mantle.

  13. Transient thermal analysis of fluid systems

    NASA Technical Reports Server (NTRS)

    Chandler, G. D.; Trust, R. D.

    1977-01-01

    Computer program performs transient thermal analysis of any 2-node to 200-node-thermal network, which transports heat by fluid flow convection. Program can be modified to add conduction along tubes and radiation.

  14. Q-Bursts: Natural ELF Radio Transients

    NASA Astrophysics Data System (ADS)

    Nickolaenko, A. P.; Hayakawa, M.; Hobara, Y.

    2010-07-01

    We overview resonance spectra and present analytical expressions for the waveforms of natural extremely low frequency transient events (Q-bursts). It is shown that model and observed waveforms are similar when a wideband receiver is used at a place with low level of industrial interference. We also describe how to detect a natural ELF transient signal embedded in the man-made noise by using the singular spectral analysis.

  15. Detection of Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Schmitt, Christian

    2011-05-01

    A core-collapse supernova (SN) would produce an expanding shell of charged particles which interact with the surrounding magnetic field of the progenitor star producing a transient radio pulse. Approximately one supernova event per century is expected in a galaxy. The radio waves emitted are detectable by a new generation of low-frequency radio telescope arrays. We present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  16. Two-phase pump transient behaviour

    SciTech Connect

    Bratu, Ch.

    1995-12-31

    Concerns regarding the efficiency, stability and safety margins of the rotodynamic pump POSEIDON P300 unit has prompted the investigation of steady state and transient behaviour. Bench tests, carried out on the IFP - Solaize multiphase loop, precede long term field endurance trial (TOTAL - Tunisia). The paper introduces a global analytical model enabling the understanding of the transient pump behaviour. Experimental results are analyzed and gathered practical conclusions enable the design of the control-regulation system.

  17. Method for Transducer Transient Suppression. I. Theory

    DTIC Science & Technology

    1992-09-01

    Vol. 92, No. 3, September 1992 Method for transducer transient suppression. I: Theory Jean C. Piquette Naval Research Laboratory. Underwater Sound...TITLE AND SUBTITLE 5. FUNDING NUMBERS Method for transducer transient suppression. I: Theo:y PE - 61153N TA - RROII-08-42 WU - DN220-161 6. AUTHOR(S) Jean...STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution unlimited. 13. ABSTRACT (Maximum 200 words) The problem of driving a transducer in

  18. Physik gestern und heute: Fragwürdiges beim Millikan-Versuch

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-09-01

    Robert A. Millikan erhielt 1923 als erster amerikanischer Physiker den Nobelpreis für Physik. Geehrt wurde er für seine Präzisionsmessungen zum Photoeffekt und zur experimentellen Bestimmung der elektrischen Elementarladung. Millikans Experimente zur Elementarladung sind auch heute noch ein Standardthema im schulischen Physikunterricht, gleichzeitig werfen sie aber eine Reihe von wissenschaftstheoretischen und ethisch relevanten Fragen auf.

  19. Transient Rechargeable Batteries Triggered by Cascade Reactions.

    PubMed

    Fu, Kun; Liu, Zhen; Yao, Yonggang; Wang, Zhengyang; Zhao, Bin; Luo, Wei; Dai, Jiaqi; Lacey, Steven D; Zhou, Lihui; Shen, Fei; Kim, Myeongseob; Swafford, Laura; Sengupta, Louise; Hu, Liangbing

    2015-07-08

    Transient battery is a new type of technology that allows the battery to disappear by an external trigger at any time. In this work, we successfully demonstrated the first transient rechargeable batteries based on dissoluble electrodes including V2O5 as the cathode and lithium metal as the anode as well as a biodegradable separator and battery encasement (PVP and sodium alginate, respectively). All the components are robust in a traditional lithium-ion battery (LIB) organic electrolyte and disappear in water completely within minutes due to triggered cascade reactions. With a simple cut-and-stack method, we designed a fully transient device with an area of 0.5 cm by 1 cm and total energy of 0.1 J. A shadow-mask technique was used to demonstrate the miniature device, which is compatible with transient electronics manufacturing. The materials, fabrication methods, and integration strategy discussed will be of interest for future developments in transient, self-powered electronics. The demonstration of a miniature Li battery shows the feasibility toward system integration for all transient electronics.

  20. Modellierung und Simulation des Substrat-Rauschens in integrierten RF CMOS-Schaltungen

    NASA Astrophysics Data System (ADS)

    Lin, L.; Xiong, J.; Mathis, W.

    2009-05-01

    Im integrierten CMOS-Schaltungsentwurf kann das Substrat-Rauschen, das vom digitalen Teil entsteht, die Funktionalität des analogen Teils stark beeinflussen. Es wird daher immer wichtiger, das Substrat als ein Medium der Rauschen-Propagation genau zu modellieren. Im vorliegenden Artikel wird ein auf der Finite Elemente Methode (FEM) und Modellordnungsreduktion (MOR) basiertes Modellierungsverfahren zur Admittanzen-Extraktion im Halbleitersubstrat vorgestellt. Nach der Diskretisierung mit FEM wird das Substrat im Allgemeinen als ein resistives/kapazitives Netz angesehen. Durch Bestimmung der Admittanz-Matrix und MOR ist es möglich ein äquivalentes Dreipol-Modell zwischen digitalem und analogem Teil über das Substrat zu bilden. Das Ergebnis der Modellierung wird dargestellt und mit numerischer Simulation des Substrat-Rauschens verglichen. Die Modellierung ermöglicht es, die Einflüsse des Substrat-Rauschens im Schaltungsentwurf zu berücksichtigen und so bestehende CMOS-Schaltungsarchitekturen zu optimieren.

  1. Variationeller Ansatz für eine integrierte Segmentierung und nicht-lineare Registrierung

    NASA Astrophysics Data System (ADS)

    Schmidt-Richberg, Alexander; Ehrhardt, Jan; Handels, Heinz

    Vierdimensionale tomographische Bilddaten ermöglichen neuartige Therapie- und Diagnoseverfahren in der medizinischen Praxis. Voraussetzung dafür sind oft die räumlich-zeitliche Segmentierung anatomischer Strukturen in den 4D- Daten und die Bestimmung ihrer dynamischen Eigenschaften durch Schätzung der 3D-Bewegungsfelder mittels nicht-linearer Registrierungsverfahren. In dieser Arbeit wird ein Ansatz vorgestellt, mit dem sich Level-Set-Segmentierung und diffusive, nicht-lineare Registrierung unter Berücksichtigung ihrer wechelseitigen Abhängigkeiten integriert lösen lassen. Die Aufgabe wird als Energieminimierung formuliert und ein variationelles Lösungsverfahren angegeben. Anschließend wird der Ansatz an Phantom- und CT-Patientendaten am Beispiel der Leber validiert.

  2. Transient diabetes insipidus in pregnancy

    PubMed Central

    Gunawardana, Kavinga; Grossman, Ashley

    2015-01-01

    Summary Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remitting spontaneously 4–6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed by placental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requires desmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria, nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, well-controlled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; her blood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m2). Laboratory data revealed low urine osmolality 89 mOsmol/kg (350–1000), serum osmolality 293 mOsmol/kg (278–295), serum sodium 144 mmol/l (135–145), potassium 4.1 mmol/l (3.5–5.0), urea 2.2 mmol/l (2.5–6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alanine transaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin with improvement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively). A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had no further evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum were normal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically, with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off all medication. This case illustrates some challenges in the diagnosis and management of transient gestational DI. Learning points Gestational DI is a rare complication of

  3. Four RNA families with functional transient structures

    PubMed Central

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5′ flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5′ UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM

  4. Four RNA families with functional transient structures.

    PubMed

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All

  5. Transient triggering of near and distant earthquakes

    USGS Publications Warehouse

    Gomberg, J.; Blanpied, M.L.; Beeler, N.M.

    1997-01-01

    We demonstrate qualitatively that frictional instability theory provides a context for understanding how earthquakes may be triggered by transient loads associated with seismic waves from near and distance earthquakes. We assume that earthquake triggering is a stick-slip process and test two hypotheses about the effect of transients on the timing of instabilities using a simple spring-slider model and a rate- and state-dependent friction constitutive law. A critical triggering threshold is implicit in such a model formulation. Our first hypothesis is that transient loads lead to clock advances; i.e., transients hasten the time of earthquakes that would have happened eventually due to constant background loading alone. Modeling results demonstrate that transient loads do lead to clock advances and that the triggered instabilities may occur after the transient has ceased (i.e., triggering may be delayed). These simple "clock-advance" models predict complex relationships between the triggering delay, the clock advance, and the transient characteristics. The triggering delay and the degree of clock advance both depend nonlinearly on when in the earthquake cycle the transient load is applied. This implies that the stress required to bring about failure does not depend linearly on loading time, even when the fault is loaded at a constant rate. The timing of instability also depends nonlinearly on the transient loading rate, faster rates more rapidly hastening instability. This implies that higher-frequency and/or longer-duration seismic waves should increase the amount of clock advance. These modeling results and simple calculations suggest that near (tens of kilometers) small/moderate earthquakes and remote (thousands of kilometers) earthquakes with magnitudes 2 to 3 units larger may be equally effective at triggering seismicity. Our second hypothesis is that some triggered seismicity represents earthquakes that would not have happened without the transient load (i

  6. Transient simulation of molten salt central receiver

    NASA Astrophysics Data System (ADS)

    Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael

    2016-05-01

    Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.

  7. Transient processes in two-barrier nanostructures

    NASA Astrophysics Data System (ADS)

    Elesin, V. F.

    2014-06-01

    An analytic solution to the problem on transient processes in a two-barrier nanostructure is found. Explicit expressions are obtained for a transient current produced by an instantly applied weak electric field. The current relaxes to a stationary state for a time ħ/Γ (Γ is the width of a resonance level), oscillating at a frequency of ξ = ɛ - ɛ R , where ɛ is the energy of electrons coming from an emitter and ɛ R is the resonance level energy. The transient current for interacting electrons is found in the quasi-classical approximation. It is shown that interaction between electrons can drastically change the transient current, especially in the presence of hysteresis of the current-voltage characteristic (CVC). Near extreme CVC values in the region of negative differential conductivity, the oscillation frequency tends to zero and becomes imaginary, compensating the decay. Thus, the transient current relaxes with very large times without oscillations. In contrast, in the case of positive differential conductivity, the oscillation frequency becomes very high, while the relaxation time remains the same, 1/Γ.

  8. A Quantitative Study of the Characteristics of Transient and Non-Transient Students in Nevada Elementary Schools

    ERIC Educational Resources Information Center

    Parr, Andrew Joseph

    2010-01-01

    The purpose of this research was to determine whether transient or mobile students attain lower levels of academic achievement than non-transient students and to identify the characteristics distinguishing transient from non-transient students. The study analyzed the assessment results, student characteristics, and school factors for approximately…

  9. Chemotaxis Control of Transient Cell Aggregation.

    PubMed

    Alexandre, Gladys

    2015-10-01

    Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding.

  10. Nonequilibrium transient dynamics of photon statistics

    NASA Astrophysics Data System (ADS)

    Ali, Md. Manirul; Zhang, Wei-Min

    2017-03-01

    We investigate the transient dynamics of photon statistics through two-time correlation functions for optical field coupled to a non-Markovian environment, described by the Fano-type Hamiltonian. We exactly solve the time-evolution of an initially nonclassical state which exhibits photon antibunching. We find that the transient correlations at different times t yield a smooth transition from antibunching to bunching photon statistics in the weak system-environment coupling regime. In the strong-coupling regime, the two-time correlations exhibit oscillations that persists both in the transient process and in the steady-state limit. The oscillatory behavior of photon statistics is a manifestation of strong non-Markovian memory dynamics where the system remains in nonequilibrium from its environment. We also find that the antibunching-to-bunching transition in the weak-coupling regime and the photon statistical oscillations in the strong-coupling regime are strongly influenced by the environment temperature.

  11. Transient cortical blindness after coronary angiography.

    PubMed

    Alp, B N; Bozbuğa, N; Tuncer, M A; Yakut, C

    2009-01-01

    Transient cortical blindness is rarely encountered after angiography of native coronary arteries or bypass grafts. This paper reports a case of transient cortical blindness that occurred 72 h after coronary angiography in a 56-year old patient. This was the patient's fourth exposure to contrast medium. Neurological examination demonstrated cortical blindness and the absence of any focal neurological deficit. A non-contrast-enhanced computed tomographic scan of the brain revealed bilateral contrast enhancement in the occipital lobes and no evidence of cerebral haemorrhage, and magnetic resonance imaging of the brain showed no pathology. Sight returned spontaneously within 4 days and his vision gradually improved. A search of the current literature for reported cases of transient cortical blindness suggested that this is a rarely encountered complication of coronary angiography.

  12. Ultrafast transient absorption measurements of heme proteins

    NASA Astrophysics Data System (ADS)

    Ye, Xiong; Demidov, Andrey; Wang, Wei; Christian, James; Champion, Paul

    1998-03-01

    Transient absorption spectra reveal the dynamics and intermediate states of the heme active site after ligand photodissociation, which helps clarify the physical process of ligand dissociation and geminate recombination. To measure the transient absorption spectra, we apply a femtosecond pump-probe technique with frequency resolved detection using a multichannel diode array. The femtosecond pulse output from a regenerative laser amplifier system is split in two; one beam pumps the optical parametric amplifier to produce a tunable wavelength pump pulse, the other beam generates a white light continuum that is varied in time with respect to pump pulse and probe the transient absorbance of the sample. We make a comparative study of myoglobin with different ligands, mutants and pH conditions.

  13. Three Optical Transients From the PQ Survey

    NASA Astrophysics Data System (ADS)

    Mahabal, A.; Drake, A. J.; Djorgovski, S. G.; Glikman, E.; Donalek, C.; Graham, M. J.; Williams, R.; Baltay, C.; Rabinowitz, D.; Bauer, A.; Scalzo, R.; Elman, N.; Jerke, J.; PQ Survey Team

    2007-07-01

    We have detected three strong optical transient in the Palomar- Quest (PQ) survey drift scans obtained at the Palomar 48-inch Samuel Oschin Telescope on 19/20/21 July 2007 UT. The transients are unresolved, and at the following J2000 coordinates: PQT070719:151221+123004 19Jul07 UT: 05:58:52 RA: 15:12:21.38 Dec: +12:30:04.0 PQT070721:221303-043900 21Jul07 UT: 08:21:22 RA: 22:13:03.91 Dec: -04:39:00.3 PQT070721:231237-051343 21Jul07 UT: 09:20:03 RA: 23:12:37.23 Dec: -05:13:43.7 For finding charts, offsets etc., please see: http://palquest.org/transients/ None of the three sources are present in the previous PQ images (reaching down to ~ 21 - 22 mag), the archival SDSS or DSS images, in NED, or the FIRST and NVSS radio surveys.

  14. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  15. Transient misfolding dominates multidomain protein folding

    PubMed Central

    Borgia, Alessandro; Kemplen, Katherine R.; Borgia, Madeleine B.; Soranno, Andrea; Shammas, Sarah; Wunderlich, Bengt; Nettels, Daniel; Best, Robert B.; Clarke, Jane; Schuler, Benjamin

    2015-01-01

    Neighbouring domains of multidomain proteins with homologous tandem repeats have divergent sequences, probably as a result of evolutionary pressure to avoid misfolding and aggregation, particularly at the high cellular protein concentrations. Here we combine microfluidic-mixing single-molecule kinetics, ensemble experiments and molecular simulations to investigate how misfolding between the immunoglobulin-like domains of titin is prevented. Surprisingly, we find that during refolding of tandem repeats, independent of sequence identity, more than half of all molecules transiently form a wide range of misfolded conformations. Simulations suggest that a large fraction of these misfolds resemble an intramolecular amyloid-like state reported in computational studies. However, for naturally occurring neighbours with low sequence identity, these transient misfolds disappear much more rapidly than for identical neighbours. We thus propose that evolutionary sequence divergence between domains is required to suppress the population of long-lived, potentially harmful misfolded states, whereas large populations of transient misfolded states appear to be tolerated. PMID:26572969

  16. Transient cavitation in fluid-structure interactions

    SciTech Connect

    Kot, C.A.; Hsieh, B.J.; Youngdahl, C.K.; Valentin, R.A.

    1981-11-01

    A generalized column separation model is extended to predict transient cavitation associated with fluid-structure interactions. The essential feature of the combined fluid-structure interaction calculations is the coupling between the fluid transient, which is computed one dimensionally, and the structural response which can be multidimensional. Proper coupling is achieved by defining an average, one-dimensional, structural velocity and by assuming a spatially uniform pressure loading of the structure. This procedure is found to be effective even for complex finite element structural models for which the required computational time step is orders of magnitude smaller than that for the fluid transient. Computational examples and comparison with experimental data show that neglecting cavitation and setting the fluid velocity at all times equal to that of the structural boundary leads to unreal negative pressure predictions. A properly coupled column separation model reproduces the important features of fluid-structure interactions, converges rapidly, and gives reasonable fluid and structural response predictions. 9 refs.

  17. Transient performance of permanent magnet synchronous motors

    NASA Astrophysics Data System (ADS)

    Borger, W. U.

    The performance of a permanent magnet synchronous machine is presented for transient conditions including: starting, load application and load removal. The machine studied possesses asynchronous torque for starting as well as synchronous torque for high efficiency and high power factor during normal operation. The transient performance of the synchronous machine is compared with a high efficiency induction machine of the same rating. The comparison presented is strictly analytical and is approached by developing the required equations for the idealized synchronous and induction machines. Solutions for the equations are approximated on the digital computer. Although the study is not universal in scope, it shows that the permanent magnet synchronous motor rivals the induction machine in weight and in transient performance while at the same time besting the induction machine from an efficiency and power factor standpoint.

  18. Transient misfolding dominates multidomain protein folding

    NASA Astrophysics Data System (ADS)

    Borgia, Alessandro; Kemplen, Katherine R.; Borgia, Madeleine B.; Soranno, Andrea; Shammas, Sarah; Wunderlich, Bengt; Nettels, Daniel; Best, Robert B.; Clarke, Jane; Schuler, Benjamin

    2015-11-01

    Neighbouring domains of multidomain proteins with homologous tandem repeats have divergent sequences, probably as a result of evolutionary pressure to avoid misfolding and aggregation, particularly at the high cellular protein concentrations. Here we combine microfluidic-mixing single-molecule kinetics, ensemble experiments and molecular simulations to investigate how misfolding between the immunoglobulin-like domains of titin is prevented. Surprisingly, we find that during refolding of tandem repeats, independent of sequence identity, more than half of all molecules transiently form a wide range of misfolded conformations. Simulations suggest that a large fraction of these misfolds resemble an intramolecular amyloid-like state reported in computational studies. However, for naturally occurring neighbours with low sequence identity, these transient misfolds disappear much more rapidly than for identical neighbours. We thus propose that evolutionary sequence divergence between domains is required to suppress the population of long-lived, potentially harmful misfolded states, whereas large populations of transient misfolded states appear to be tolerated.

  19. Transient Pressure Test Article (TPTA) Test

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at the Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

  20. Transient Pressure Test Article (TPTA) Test Stand

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at thw Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

  1. Spectroscopic investigation of highly transient pinch plasmas

    SciTech Connect

    Bergmann, K.; Engel, A.; Lebert, R.; Rosmej, O.N.; Rosmej, F.B.; Gavrilescu, C.; Neff, W.

    1997-11-01

    The temporal evolution of neon pinch plasmas, generated in a 2 kJ plasma focus device, has been investigated by x-ray spectroscopic methods for two sets of device parameters. These two sets lead to characteristic differences of the K-shell emission. Stationary models are shown to fail to explain the experimental observations even qualitatively. Transient spectra analysis shows that the characteristic differences observed can be referred to different transient modes of plasma dynamics. The spectra analysis includes beside resonance lines also dielectronic satellites and recombination continua. The results concerning the development of the plasma parameters achieved by the spectra modeling are supported by independent measurements of the time resolved K-shell emission and by optical streak images of the pinch plasma dynamics, which confirms the reliability of the transient spectroscopic analysis presented. {copyright} {ital 1997} {ital The American Physical Society}

  2. Earthquake triggering by transient and static deformations

    USGS Publications Warehouse

    Gomberg, J.; Beeler, N.M.; Blanpied, M.L.; Bodin, P.

    1998-01-01

    Observational evidence for both static and transient near-field and far-field triggered seismicity are explained in terms of a frictional instability model, based on a single degree of freedom spring-slider system and rate- and state-dependent frictional constitutive equations. In this study a triggered earthquake is one whose failure time has been advanced by ??t (clock advance) due to a stress perturbation. Triggering stress perturbations considered include square-wave transients and step functions, analogous to seismic waves and coseismic static stress changes, respectively. Perturbations are superimposed on a constant background stressing rate which represents the tectonic stressing rate. The normal stress is assumed to be constant. Approximate, closed-form solutions of the rate-and-state equations are derived for these triggering and background loads, building on the work of Dieterich [1992, 1994]. These solutions can be used to simulate the effects of static and transient stresses as a function of amplitude, onset time t0, and in the case of square waves, duration. The accuracies of the approximate closed-form solutions are also evaluated with respect to the full numerical solution and t0. The approximate solutions underpredict the full solutions, although the difference decreases as t0, approaches the end of the earthquake cycle. The relationship between ??t and t0 differs for transient and static loads: a static stress step imposed late in the cycle causes less clock advance than an equal step imposed earlier, whereas a later applied transient causes greater clock advance than an equal one imposed earlier. For equal ??t, transient amplitudes must be greater than static loads by factors of several tens to hundreds depending on t0. We show that the rate-and-state model requires that the total slip at failure is a constant, regardless of the loading history. Thus a static load applied early in the cycle, or a transient applied at any time, reduces the stress

  3. Positron beam studies of transients in semiconductors

    NASA Astrophysics Data System (ADS)

    Beling, C. D.; Ling, C. C.; Cheung, C. K.; Naik, P. S.; Zhang, J. D.; Fung, S.

    2006-02-01

    Vacancy-sensing positron deep level transient spectroscopy (PDLTS) is a positron beam-based technique that seeks to provide information on the electronic ionization levels of vacancy defects probed by the positron through the monitoring of thermal transients. The experimental discoveries leading to the concept of vacancy-sensing PDLTS are first reviewed. The major problem associated with this technique is discussed, namely the strong electric fields establish in the near surface region of the sample during the thermal transient which tend to sweep positrons into the contact with negligible defect trapping. New simulations are presented which suggest that under certain conditions a sufficient fraction of positrons may be trapped into ionizing defects rendering PDLTS technique workable. Some suggestions are made for techniques that might avoid the problematic electric field problem, such as optical-PDLTS where deep levels are populated using light and the use of high forward bias currents for trap filling.

  4. 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.

  5. Was leistet ein Sportler? Kraft, Leistung und Energie im Muskel

    NASA Astrophysics Data System (ADS)

    Thaller, Sigrid; Mathelitsch, Leopold

    2006-01-01

    Der Leistungsbegriff ist im Sport weiter gefasst als in der Physik. In beiden Fällen liegt der Fokus jedoch auf einer pro Zeiteinheit erfolgten Energieumsetzung. Allerdings gibt die rein physikalische Leistung nicht immer Auskunft über den Energieumsatz der Muskeln. Die Muskelkraft hängt von der Kontraktionsgeschwindigkeit des Muskels ab. Ein Muskel verhält sich also anders als eine Feder. Für den Hochleistungssport müssen die Energieumsätze der Muskeln durch spezielle Trainings- und Nahrungsprogramme optimiert werden.

  6. Transient thermal camouflage and heat signature control

    NASA Astrophysics Data System (ADS)

    Yang, Tian-Zhi; Su, Yishu; Xu, Weikai; Yang, Xiao-Dong

    2016-09-01

    Thermal metamaterials have been proposed to manipulate heat flux as a new way to cloak or camouflage objects in the infrared world. To date, however, thermal metamaterials only operate in the steady-state and exhibit detectable, transient heat signatures. In this letter, the theoretical basis for a thermal camouflaging technique with controlled transient diffusion is presented. This technique renders an object invisible in real time. More importantly, the thermal camouflaging device instantaneously generates a pre-designed heat signature and behaves as a perfect thermal illusion device. A metamaterial coating with homogeneous and isotropic thermal conductivity, density, and volumetric heat capacity was fabricated and very good camouflaging performance was achieved.

  7. Computer animation of modal and transient vibrations

    NASA Technical Reports Server (NTRS)

    Lipman, Robert R.

    1987-01-01

    An interactive computer graphics processor is described that is capable of generating input to animate modal and transient vibrations of finite element models on an interactive graphics system. The results from NASTRAN can be postprocessed such that a three dimensional wire-frame picture, in perspective, of the finite element mesh is drawn on the graphics display. Modal vibrations of any mode shape or transient motions over any range of steps can be animated. The finite element mesh can be color-coded by any component of displacement. Viewing parameters and the rate of vibration of the finite element model can be interactively updated while the structure is vibrating.

  8. Transient behavior of ultracapacitors and supercapacitors

    SciTech Connect

    Huggins, R.A.

    1995-12-31

    Several different mechanisms can be used to provide short term high power pulses from electrochemical systems. Their fundamental characteristics and applicability to the different types of transient output requirements will be discussed. When significant amounts of energy must be delivered, the most favorable materials operate by means of insertion reactions. The methods that can be employed to quantitatively evaluate the critical materials parameters will be described. Spreadsheet techniques are especially useful for modeling the transient transport behavior of components containing such materials under various boundary conditions. LaPlace transform methods can then be used to convert information about the parameters of individual components into the dynamic response of the total system.

  9. Transient analysis using conical shell elements

    NASA Technical Reports Server (NTRS)

    Yang, J. C. S.; Goeller, J. E.; Messick, W. T.

    1973-01-01

    The use of the NASTRAN conical shell element in static, eigenvalue, and direct transient analyses is demonstrated. The results of a NASTRAN static solution of an externally pressurized ring-stiffened cylinder agree well with a theoretical discontinuity analysis. Good agreement is also obtained between the NASTRAN direct transient response of a uniform cylinder to a dynamic end load and one-dimensional solutions obtained using a method of characteristics stress wave code and a standing wave solution. Finally, a NASTRAN eigenvalue analysis is performed on a hydroballistic model idealized with conical shell elements.

  10. Transient Molecular Transfer During Vacuum Testing

    NASA Technical Reports Server (NTRS)

    Perry, Radford L.

    2011-01-01

    A common question in contamination budgeting involves the loss of collected volatiles during ambient I&T activity under vacuum and the resultant cross-contamination from outgassing. (1) How much of the material collected under ambient conditions evaporates under vacuum? (2) Why do pristine surfaces sometimes show increased molecular contamination after vacuum bakeout? (3) How much of the collected molecular contamination is transient (i.e. migratory) and how much is permanent? Measuring the transient deposition may be accomplished using a thermally passive QCM

  11. Transient aspects of stream interface signatures

    SciTech Connect

    Crooker, N.U.; Shodhan, S.; Forsyth, R.J.; Burton, M.E.; Gosling, J.T.; Fitzenreiter, R.J.; Lepping, R.P.

    1999-06-01

    Although stream interfaces are steady-state, corotating boundaries between slow and fast solar wind, their signatures are sometimes associated with transient features. Here the authors illustrate two modes of association: interfaces trailing interplanetary coronal mass ejections (ICMEs) at 1 AU and interfaces within ICMEs in the range 4--5 AU. The former are readily understood as boundaries between transient slow wind and steady-state fast wind, where the ICMEs add variability to the interface signatures. The latter are puzzling and may be related to evolution of interfaces.

  12. Transient astronomy with the Gaia satellite.

    PubMed

    Hodgkin, Simon T; Wyrzykowski, Łukasz; Blagorodnova, Nadejda; Koposov, Sergey

    2013-06-13

    Gaia is a cornerstone European Space Agency astrometry space mission and a successor to the Hipparcos mission. Gaia will observe the whole sky for 5 years, providing a serendipitous opportunity for the discovery of large numbers of transient and anomalous events, e.g. supernovae, novae and microlensing events, gamma-ray burst afterglows, fallback supernovae, as well as theoretical or unexpected phenomena. In this paper, we discuss our preparations to use Gaia to search for transients at optical wavelengths, and briefly describe the early detection, classification and prompt publication of anomalous sources.

  13. Wavelet analysis of fusion plasma transients

    SciTech Connect

    Dose, V.; Venus, G.; Zohm, H.

    1997-02-01

    Analysis of transient signals in the diagnostic of fusion plasmas often requires the simultaneous consideration of their time and frequency information. The newly emerging technique of wavelet analysis contains both time and frequency domains. Therefore it can be a valuable tool for the analysis of transients. In this paper the basic method of wavelet analysis is described. As an example, wavelet analysis is applied to the well-known phenomena of mode locking and fishbone instability. The results quantify the current qualitative understanding of these events in terms of instantaneous frequencies and amplitudes and encourage applications of the method to other problems. {copyright} {ital 1997 American Institute of Physics.}

  14. Transient Detections from Pan-STARRS

    NASA Astrophysics Data System (ADS)

    Rodney, Steven A.

    2009-01-01

    The first Pan-STARRS telescope, PS1, is now collecting survey data on a nightly basis, for the first time producing new transient detections. One of the primary branches of the PS1 science strategy is the Medium Deep survey, which will detect thousands of supernovae and other explosive transients. This extraordinary yield from a single survey will allow us to put new constraints on the nature of Dark Energy and to improve our understanding of the progenitor systems that produce Type Ia Supernovae. We present early detections from the Fall 2008 PS1 campaign.

  15. Integrierte Segmentierung und Trajektorienberechnung mittels diffeomorpher Registrierung in räumlich-zeitlichen CT-Bildfolgen

    NASA Astrophysics Data System (ADS)

    Schmidt-Richberg, Alexander; Ehrhardt, Jan; Werner, René; Handels, Heinz

    Verfahren zur integrierten Segmentierung und Registrierung von 4D-Bilddaten ermöglichen die Berücksichtigung der gegenseitigen Abhängigkeiten beider Komponenten. Bestehende Ansätze konzentrieren sich dabei meist auf die Betrachtung zweier 3D-Bilder und lassen sich nicht direkt auf vollständige Bildfolgen übertragen. In dieser Arbeit wird ein Verfahren vorgestellt, in dem ein diffeomorpher Registrierungsansatz verwendet wird, um eine integrierte Berechnung von Segmentierungen und 3D-Voxeltrajektorien in 4D-Daten zu ermöglichen.

  16. 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.

  17. Laser spectroscopy and dynamics of transient species

    SciTech Connect

    Clouthier, D.J.

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  18. Circuit controls transients in SCR inverters

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1964-01-01

    Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

  19. Linac RF control at transient beamloading

    NASA Astrophysics Data System (ADS)

    Chernogubovsky, M. A.; Sugimoto, M.

    1999-06-01

    Effective RF control design is carried out under electrodynamic property analysis of the transient beam excitation, which gives the basic principle and support method for RF control. The main parameters of the RF system are defined under the directional selective coupling application; the beam dynamics with control characteristics are optimized for operating mode electrodynamics.

  20. Transient cortical blindness after coronary artery angiography.

    PubMed

    Terlecki, Michał; Wojciechowska, Wiktoria; Rajzer, Marek; Jurczyszyn, Artur; Bazan-Socha, Stanisława; Bryniarski, Leszek; Czarnecka, Danuta

    2013-01-01

    Coronary angiography is the current gold standard for the diagnosis of ischemic heart disease and therefore the prevalence of percutaneous coronary procedures such as angiography and angioplasty is high. The occurrence of cerebral complications after coronary angiography and coronary angioplasty is low and it mainly includes transient ischemic attack and stroke. The prevalence of transient cortical blindness after X-ray contrast media is low and it is usually seen after cerebral angiography. Until now only a few cases of transient cortical blindness have been described after coronary artery angiography. Regarding the spread of coronary angiography worldwide and in Poland this complication is uniquely rare. A 32-year-old man with multiple extrasystolic ventricular arrhythmia suggesting Brugada syndrome diagnosis according to morphology of the left bundle branch block and with decreased left ventricular ejection fraction was admitted to the First Department of Cardiology and Hypertension, Medical College of the Jagiellonian University in Krakow. Coronary angiography was performed in order to exclude ischemic etiology of the observed abnormalities. No arteriosclerotic lesions were found in coronary arteries. Transient cortical blindness was observed directly after angiography which may have been caused by the neurotoxic effect of the used X-ray contrast medium. In ophthalmologic and neurologic examination as well as in the cerebral computed tomography scan no pathologies were found. Visual impairment disappeared totally within several hours.

  1. Intermittent/transient faults in digital systems

    NASA Technical Reports Server (NTRS)

    Masson, G. M.; Glazer, R. E.

    1982-01-01

    Containment set techniques are applied to 8085 microprocessor controllers so as to transform a typical control system into a slightly modified version, shown to be crashproof: after the departure of the intermittent/transient fault, return to one proper control algorithm is assured, assuming no permanent faults occur.

  2. The pathology of transient regional osteoporosis.

    PubMed

    McCarthy, E F

    1998-01-01

    Biopsy specimens from 19 patients with transient regional osteoporosis were studied. All patients presented with pain. There were nine patients with transient osteoporosis of the hip. Six of these specimens were therapeutic core biopsies, and three were femoral heads removed during total hip replacement. The other patients with osteoporosis in different locations had biopsies to rule out infection or neoplasm. Five of these patients had transient osteoporosis of the knee. Three had ankle involvement and two had involvement of the tibial shaft. Plain radiographs were available for study in all cases, and either a bone scan or an MRI was studied in each case. Except for one patient who was lost to follow-up, all had resolution of symptoms and radiographic changes. The histologic changes in the biopsies were distinctive, although they were present in varying degrees. There was edema and reactive bone formation in the marrow spaces. In addition, osteoclastic bone resorption was active in 14 of the 19 cases. Although lipid cysts were sometimes found in the marrow spaces, there was no evidence of fat necrosis or bone necrosis. The high bone turnover and absence of fat necrosis suggests that this disorder is a vasomotor response rather than an early stage of osteonecrosis. Awareness of these characteristic histologic changes should enable the pathologist to make a specific diagnosis of transient regional osteoporosis when a biopsy is required.

  3. Interpreting signals from astrophysical transient experiments

    PubMed Central

    O’Brien, Paul T.; Smartt, Stephen J.

    2013-01-01

    Time-domain astronomy has come of age with astronomers now able to monitor the sky at high cadence, both across the electromagnetic spectrum and using neutrinos and gravitational waves. The advent of new observing facilities permits new science, but the ever-increasing throughput of facilities demands efficient communication of coincident detections and better subsequent coordination among the scientific community so as to turn detections into scientific discoveries. To discuss the revolution occurring in our ability to monitor the Universe and the challenges it brings, on 25–26 April 2012, a group of scientists from observational and theoretical teams studying transients met with representatives of the major international transient observing facilities at the Kavli Royal Society International Centre, UK. This immediately followed the Royal Society Discussion Meeting ‘New windows on transients across the Universe’ held in London. Here, we present a summary of the Kavli meeting at which the participants discussed the science goals common to the transient astronomy community and analysed how to better meet the challenges ahead as ever more powerful observational facilities come on stream. PMID:23630383

  4. Transient Microphonic Effects In Superconducting Cavities

    SciTech Connect

    Thomas Powers; G. Davis; Lawrence King

    2005-07-10

    A number of experiments were performed on an installed and operational 5-cell CEBAF cavity to determine the minimum time required to reestablish stable gradient after a cavity window arc trip. Once it was determined that gradient could be reestablished within 10 ms by applying constant power RF signal in and a voltage controlled Oscillator-phase locked loop based system (VCO-PLL), a second experiment was performed to determine if stable gradient could be reestablished using a fixed frequency RF system with a simple gradient based closed loop control system. During this test, instabilities were observed in the cavity forward power signal, which were determined to be microphonic in nature. These microphonic effects were quantified using a cavity resonance monitor and a VCO{_}PLL RF system. Two types of microphonic effects were observed depending on the type of arc event. If the arc occurred in the vacuum space between the warm and cold windows, the transient frequency shift was about 75 Hz peak-to-peak. If the arc occurred on the cavity side of the cold window the transient frequency shift was about 400 Hz peak-to-peak. The background microphonics level for the tested cavity was approximately 30 Hz peak-to-peak. Experimental results, analysis of the resultant klystron power transients, the decay time of the transients, and the implications with respect to fast reset algorithms will be presented.

  5. Inhomogeneous Forcing and Transient Climate Sensitivity

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.

    2014-01-01

    Understanding climate sensitivity is critical to projecting climate change in response to a given forcing scenario. Recent analyses have suggested that transient climate sensitivity is at the low end of the present model range taking into account the reduced warming rates during the past 10-15 years during which forcing has increased markedly. In contrast, comparisons of modelled feedback processes with observations indicate that the most realistic models have higher sensitivities. Here I analyse results from recent climate modelling intercomparison projects to demonstrate that transient climate sensitivity to historical aerosols and ozone is substantially greater than the transient climate sensitivity to CO2. This enhanced sensitivity is primarily caused by more of the forcing being located at Northern Hemisphere middle to high latitudes where it triggers more rapid land responses and stronger feedbacks. I find that accounting for this enhancement largely reconciles the two sets of results, and I conclude that the lowest end of the range of transient climate response to CO2 in present models and assessments (less than 1.3 C) is very unlikely.

  6. Transient global amnesia and left frontal haemorrhage.

    PubMed Central

    Jacome, D. E.; Yanez, G. F.

    1988-01-01

    A patient developed spontaneous, acute, dominant frontal lobe haemorrhage neighbouring on a zone of pre-existing post-traumatic encephalomalacia manifesting clinically as transient global amnesia. Amnesia can be secondary to disease of the frontal lobe, affecting pathways interconnecting the basal forebrain and hippocampus of the temporal lobe. Images Figure 1 PMID:3174526

  7. Detecting aseismic strain transients from seismicity data

    NASA Astrophysics Data System (ADS)

    Llenos, A. L.; McGuire, J. J.

    2011-06-01

    Aseismic deformation transients such as fluid flow, magma migration, and slow slip can trigger changes in seismicity rate. We present a method that can detect these seismicity rate variations and utilize these anomalies to constrain the underlying variations in stressing rate. Because ordinary aftershock sequences often obscure changes in the background seismicity caused by aseismic processes, we combine the stochastic Epidemic Type Aftershock Sequence model that describes aftershock sequences well and the physically based rate- and state-dependent friction seismicity model into a single seismicity rate model that models both aftershock activity and changes in background seismicity rate. We implement this model into a data assimilation algorithm that inverts seismicity catalogs to estimate space-time variations in stressing rate. We evaluate the method using a synthetic catalog, and then apply it to a catalog of M ≥ 1.5 events that occurred in the Salton Trough from 1990 to 2009. We validate our stressing rate estimates by comparing them to estimates from a geodetically derived slip model for a large creep event on the Obsidian Buttes fault. The results demonstrate that our approach can identify large aseismic deformation transients in a multidecade long earthquake catalog and roughly constrain the absolute magnitude of the stressing rate transients. Our method can therefore provide a way to detect aseismic transients in regions where geodetic resolution in space or time is poor.

  8. Detecting aseismic strain transients from seismicity data

    USGS Publications Warehouse

    Llenos, A.L.; McGuire, J.J.

    2011-01-01

    Aseismic deformation transients such as fluid flow, magma migration, and slow slip can trigger changes in seismicity rate. We present a method that can detect these seismicity rate variations and utilize these anomalies to constrain the underlying variations in stressing rate. Because ordinary aftershock sequences often obscure changes in the background seismicity caused by aseismic processes, we combine the stochastic Epidemic Type Aftershock Sequence model that describes aftershock sequences well and the physically based rate- and state-dependent friction seismicity model into a single seismicity rate model that models both aftershock activity and changes in background seismicity rate. We implement this model into a data assimilation algorithm that inverts seismicity catalogs to estimate space-time variations in stressing rate. We evaluate the method using a synthetic catalog, and then apply it to a catalog of M???1.5 events that occurred in the Salton Trough from 1990 to 2009. We validate our stressing rate estimates by comparing them to estimates from a geodetically derived slip model for a large creep event on the Obsidian Buttes fault. The results demonstrate that our approach can identify large aseismic deformation transients in a multidecade long earthquake catalog and roughly constrain the absolute magnitude of the stressing rate transients. Our method can therefore provide a way to detect aseismic transients in regions where geodetic resolution in space or time is poor. Copyright 2011 by the American Geophysical Union.

  9. Design and transient behavior of magnetic gears

    NASA Astrophysics Data System (ADS)

    Zheng, Ping; Bai, Jingang; Lin, Jia; Fu, Zhenxing; Song, Zhiyi; Lin, Fei

    2014-05-01

    The torque density is a key factor for magnetic gears. To obtain maximum torque density, the design principle of magnetic gears is proposed and the maximum transmitting torque is investigated under different combinations of the inner and outer permanent magnets (PM) rotor pole pairs. The research proves that the maximum transmitting torque and the minimum torque ripple can be obtained only when the ratio of the outer and inner PM pole pair numbers is fractional. Then, the optimal selection of the span ratio and thickness of magnetic blocks in the stationary modulating ring is investigated to obtain the maximum torque. Meanwhile, analyses of the losses of various parts in the magnetic gear show that the loss of the PMs is about 70% of the total losses. Therefore, the method of dividing the PM into several pieces along the circumferential direction is employed to reduce the PM loss, which makes the PM loss reduced by 73%. Additionally, the transient behavior of the magnetic gear is analyzed, indicating that the lower torsional stiffness is the main reason for oscillations during transient changes in speed and load. To suppress oscillations due to transients, damper windings are employed and the transient time and the maximum oscillation amplitude are reduced by 25% and 20%, respectively.

  10. Transient Ultrasonic Spectroscopy Using Metal Wire Explosions

    NASA Astrophysics Data System (ADS)

    Kim, Min G.; Kim, Yong T.

    1989-06-01

    A transient ultrasonic spectroscopy system has been developed using a sound pulse generated by a metal explosion and optical detection of the sound. The electric explosion of metal wire produces a short-duration acoustic pulse containing a broad Fourier frequency spectrum in the range 10 to 200 kHz. The acoustic pulse profiles at two distances are monitored by the transient photorefractive deflection of collimated probe laser beams, one of which is displaced from but parallel to the other. An angular magnification(an increase in sensitivity of detection) of the deflection is achieved by refracting the deflected laser beam through a peripheral section of a converging lens. The transient deflection is observed by using a knife-edge to block half of the probe beam and detecting the signal with a fast photodiode. By taking the difference between the electronic signal outputs of the two photodiodes, a pair of noise free transient deflection signals is recorded. Fourier analysis of these probe deflection signals provides the absorption spectrum, and an example for atmospheric air is given. The experimental results are attributed to combined absorption due to the classical effects of thermal conduction and viscosity, absorption due to rotational relaxation and due to the humidity dependent vibrational relaxation of nitrogen and oxygen.

  11. The Zwicky transient facility observing system

    NASA Astrophysics Data System (ADS)

    Smith, Roger M.; Dekany, Richard G.; Bebek, Christopher; Bellm, Eric; Bui, Khanh; Cromer, John; Gardner, Paul; Hoff, Matthew; Kaye, Stephen; Kulkarni, Shrinivas; Lambert, Andrew; Levi, Michael; Reiley, Dan

    2014-07-01

    The Zwicky Transient Facility (ZTF) is a synoptic optical survey for high-cadence time-domain astronomy. Building upon the experience and infrastructure of the highly successful Palomar Transient Factory (PTF) team, ZTF will survey more than an order of magnitude faster than PTF in sky area and volume in order to identify rare, rapidly varying optical sources. These sources will include a trove of supernovae, exotic explosive transients, unusual stellar variables, compact binaries, active galactic nuclei, and asteroids. The single-visit depth of 20.4 mag is well matched to spectroscopic follow-up observations, while the co-added images will provide wide sky coverage 1.5 - 2 mag deeper than SDSS. The ZTF survey will cover the entire Northern Sky and revisit fields on timescales of a few hours, providing hundreds of visits per field each year, an unprecedented cadence, as required to detect fast transients and variability. This high-cadence survey is enabled by an observing system based on a new camera having 47 deg2 field of view - a factor of 6.5 greater than the existing PTF camera - equipped with fast readout electronics, a large, fast exposure shutter, faster telescope and dome drives, and various measures to optimize delivered image quality. Our project has already received an initial procurement of e2v wafer-scale CCDs and we are currently fabricating the camera cryostat. International partners and the NSF committed funds in June 2014 so construction can proceed as planned to commence engineering commissioning in 2016 and begin operations in 2017. Public release will allow broad utilization of these data by the US astronomical community. ZTF will also promote the development of transient and variable science methods in preparation for the seminal first light of LSST.

  12. Diagnosing transient ionization in dynamic events

    NASA Astrophysics Data System (ADS)

    Doyle, J. G.; Giunta, A.; Madjarska, M. S.; Summers, H.; O'Mullane, M.; Singh, A.

    2013-09-01

    Aims: The present study aims to provide a diagnostic line ratio that will enable the observer to determine whether a plasma is in a state of transient ionization. Methods: We use the Atomic Data and Analysis Structure (ADAS) to calculate line contribution functions for two lines, Si iv 1394 Å and O iv 1401 Å, formed in the solar transition region. The generalized collisional-radiative theory is used. It includes all radiative and electron collisional processes, except for photon-induced processes. State-resolved direct ionization and recombination to and from the next ionization stage are also taken into account. Results: For dynamic bursts with a decay time of a few seconds, the Si iv 1394 Å line can be enhanced by a factor of 2-4 in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature due to transient ionization compared to ionization equilibrium conditions. On the other hand, the O iv 1401 Å does not show such any enhancement. Thus the ratio of these two lines, which can be observed with the Interface Region Imaging Spectrograph, can be used as a diagnostic of transient ionization. Conclusions: We show that simultaneous high-cadence observations of two lines formed in the solar transition region may be used as a direct diagnostic of whether the observed plasma is in transient ionization. The ratio of these two lines can change by a factor of four in a few seconds owing to transient ionization alone.

  13. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics.

    PubMed

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L

    2016-04-14

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g(-1) is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.

  14. 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.

  15. Modellgestützte Fehlererkennung und Diagnose für Common-Rail-Einspritzsysteme

    NASA Astrophysics Data System (ADS)

    Clever, Sebastian

    Moderne Pkw-Dieselmotoren sind mit verschiedensten komplexen mechatronischen Komponenten ausgestattet. So kommen neben Abgasrückführsystemen zur Minderung der Stickoxidemissionen und Turboladern zur Steigerung der Leistungsdichte insbesondere elektronisch gesteuerte Mehrfach-Einspritzsysteme zum Einsatz. Deshalb erhöht sich die Bedeutung einer umfassenden Fehlererkennung und Diagnose, zusätzlich zu den bekannten OBD- und EOBD-Vorgaben, im Rahmen steigender Anforderungen an die Zuverlässigkeit und Verfügbarkeit. Um diese Anforderungen zu erfüllen, bieten sich modellbasierte Verfahren an. Ihr Stand in verschiedenen Gebieten wird zum Beispiel in [1-6] beschrieben. Mit dem Einsatz modellgestützter Fehlererkennungsverfahren bei Verbrennungsmotoren beschäftigen sich beispielsweise [7-18].

  16. Zur ethischen Dimension von Renaturierungsökologie und Ökosystemrenaturierung

    NASA Astrophysics Data System (ADS)

    Ott, Konrad

    Die wissenschaftlich angeleitete Ökosystemrena-turierung kann mittlerweile als eine etablierte Praxis im Bereich des Naturschutzes gelten. Diese Praxis bezieht sich notwendigerweise auf Ziele und Werte und weist damit auch eine naturethische Dimension auf. Daher hat diese Praxis die Aufmerksamkeit auch von Sozialwissenschaftlern und Ethikern auf sich gezogen. Dieses Kapitel geht der Frage nach, wie sich die naturethische Dimension der Ökosystemrenaturierung analysieren und inhaltlich bestimmen lässt. Hierzu erweist sich auch die Auseinandersetzung mit Philosophen als hilfreich, die der Ökosystemrenaturierung ein technizistisches Naturverständnis vorgeworfen haben. Am Ende des Kapitels wird ein in sich gestuftes mögliches naturethisches Selbstverständnis der Ökosystemrenaturierung diskutiert, das den an dieser Praxis Beteiligten Freiheitsgrade der Positionierung belässt.

  17. Exploring the transient sky: from surveys to simulations

    NASA Astrophysics Data System (ADS)

    Carbone, Dario

    2016-01-01

    The transient sky is very important to study the dynamics of the Universe on human timescales. Transient sources are seen in every band of the electromagnetic spectrum, from low radio frequencies to gamma-ray energies, and produced by nearby flare stars to cosmological gamma-ray bursts.We have performed a transient survey of four different fields with the LOw Frequency Array (LOFAR) at 150 MHz. LOFAR is a new generation radio interferometer which is observing at very low radio frequencies, a so far relatively unexplored frequency domain for transient searches. No credible transients were detected in our survey, but we were able to set stringent upper limits on the transient surface density using three new statistical methods. We also calculated the transient surface density as a function of the timescale of the transients, and established that the upper limits we can set vary up to two orders of magnitude for different timescales.We have explored the complex relation between flux density, timescale and transient surface density, and developed a simulation method to calculate the transient rate as a function of both the flux and the duration of transients for different shapes of their lightcurves and for a given observing strategy. This method is independent of the nature of transient sources, and the instrument or the frequency of the observations. Therefore, this provides a tool for transient surveys carried out by current and future observatories across the electromagnetic spectrum.

  18. Toolmanagement - Werkzeuge und Prozesse als Schlüssel für eine effiziente Produktion

    NASA Astrophysics Data System (ADS)

    Enßle, Magnus

    In Bezug auf die Fertigungskosten nehmen die Werkzeugkosten mit 3% einen sehr kleinen und daher vermeintlich unwichtigen Posten ein. HoheKosten ergeben sich aber meist indirekt durch Maschinenstillstandszeiten wegen fehlender oder falscher Werkzeuge, wegen ineffektiven Rüstvorgängen, umständlicher Werkzeuglogistik, unnötig hoher Bestände, unabgestimmter Abläufe, nicht aktueller Fertigungsunterlagen sowie mangelhafter Informationsflüsse zwischen Planung, Vorbereitung und Ausführung in der Fertigung [1].

  19. Single Event Transients in Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; McMorrow, Dale

    2005-01-01

    On November 5, 2001, a processor reset occurred on board the Microwave Anisotropy Probe (MAP), a NASA mission to measure the anisotropy of the microwave radiation left over from the Big Bang. The reset caused the spacecraft to enter a safehold mode from which it took several days to recover. Were that to happen regularly, the entire mission would be compromised, so it was important to find the cause of the reset and, if possible, to mitigate it. NASA assembled a team of engineers that included experts in radiation effects to tackle the problem. The first clue was the observation that the processor reset occurred during a solar event characterized by large increases in the proton and heavy ion fluxes emitted by the sun. To the radiation effects engineers on the team, this strongly suggested that particle radiation might be the culprit, particularly when it was discovered that the reset circuit contained three voltage comparators (LM139). Previous testing revealed that large voltage transients, or glitches appeared at the output of the LM139 when it was exposed to a beam of heavy ions [NI96]. The function of the reset circuit was to monitor the supply voltage and to issue a reset command to the processor should the voltage fall below a reference of 2.5 V [PO02]. Eventually, the team of engineers concluded that ionizing particle radiation from the solar event produced a negative voltage transient on the output of one of the LM139s sufficiently large to reset the processor on MAP. Fortunately, as of the end of 2004, only two such resets have occurred. The reset on MAP was not the first malfunction on a spacecraft attributed to a transient. That occurred shortly after the launch of NASA s TOPEX/Poseidon satellite in 1992. It was suspected, and later confirmed, that an anomaly in the Earth Sensor was caused by a transient in an operational amplifier (OP-15) [KO93]. Over the next few years, problems on TDRS, CASSINI, [PR02] SOHO [HA99,HA01] and TERRA were also attributed

  20. Transient tracer applications in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Stöven, T.; Tanhua, T.; Hoppema, M.

    2014-10-01

    Transient tracers can be used to constrain the Inverse-Gaussian transit time distribution (IG-TTD) and thus provide information about ocean ventilation. Individual transient tracers have different time and application ranges which are defined by their atmospheric history (chronological transient tracers) or their decay rate (radioactive transient tracers). The classification ranges from tracers for highly ventilated water masses, e.g. sulfur hexafluoride (SF6), the decay of Tritium (δ3H) and to some extent also dichlorodifluoromethane (CFC-12) to tracers for less ventilated deep ocean basins, e.g. CFC-12, Argon-39 (39Ar) and radiocarbon (14C). The IG-TTD can be empirically constrained by using transient tracer couples with sufficiently different input functions. Each tracer couple has specific characteristics which influence the application limit of the IG-TTD. Here we provide an overview of commonly used transient tracer couples and their validity areas within the IG-TTD by using the concept of tracer age differences (TAD). New measured CFC-12 and SF6 data from a section along 10° E in the Southern Ocean in 2012 are presented. These are combined with a similar data set of 1998 along 6° E in the Southern Ocean as well as with 39Ar data from the early 1980s in the western Atlantic Ocean and the Weddell Sea for investigating the application limit of the IG-TTD and to analyze changes in ventilation in the Southern Ocean. We found that the IG-TTD can be constrained south to 46° S which corresponds to the Subantarctic Front (SAF) denoting the application limit. The constrained IG-TTD north of the SAF shows a slight increase in mean ages between 1998 and 2012 in the upper 1200 m between 42-46° S. The absence of SF6 inhibits ventilation analyses below this depth. The time lag analysis between the 1998 and 2012 data shows an increase in ventilation down to 1000 m and a steady ventilation between 2000 m-bottom south of the SAF between 51-55° S.

  1. SPIRITS Discoveries of New Infrared Transients and Variables

    NASA Astrophysics Data System (ADS)

    Jencson, J. E.; Kasliwal, M. M.; Tinyanont, S.; Cao, Y.; Prince, T.; Lau, R. M.; Perley, D.; Masci, F.; Helou, G.; Armus, L.; Surace, J.; Van Dyk, S. D.; Cody, A.; Boyer, M. L.; Khan, R.; Bond, H. E.; Monson, A.; Bally, J.; Levesque, E.; Williams, R.; Whitelock, P. A.; Mohamed, S.; Gehrz, R. D.; Amodeo, S.; Shenoy, D.; Carlon, R.; Cass, A.; Corgan, D.; Dykhoff, D.; Faella, J.; Gburek, T.; Smith, N.; Cantiello, M.; Langer, N.; Ofek, E.; Johansson, J.; Parthasarathy, M.; Fox, O.; Hsiao, E.; Phillips, M.; Morrell, N.; Gonzalez, C.; Contreras, C.

    2016-04-01

    We report several recently discovered mid-infrared transients/strong variables found in the course of the Spitzer InfraRed Intensive Transients Survey (SPIRITS), using Spitzer Early Release Data (ATel #6644, #7929, #8688).

  2. Design und Analyse elektrisch kleiner Antennen für den Einsatz in UHF RFID Transpondern

    NASA Astrophysics Data System (ADS)

    Herschmann, R.; Camp, M.; Eul, H.

    2006-09-01

    RFID Systeme werden seit Anfang der neunziger Jahre mit stetig zunehmender Verbreitung im Bereich der automatischen Produktidentifikation, der Diebstahlsicherung (EAS, Electronic Article Surveillance) und für automatische Zutrittskontrollsysteme eingesetzt. Objekte werden hierzu mit einem Transponder ausgestattet, der aus einer Antenne und einem Chip auf einem Trägermaterial besteht. Von großem Interesse ist die Entwicklung und Optimierung von passiven Transpondern für den Einsatz in UHF RFID Systemen. Diese Transponder beziehen die Energie zum Betrieb des Chips aus dem elektromagnetischen Feld einer Schreib-Leseeinheit. Hierfür ist neben der Anpassung der Eingangsimpedanz der Antenne an die Chipimpedanz auch eine möglichst hohe Bandbreite der Antennen wünschenswert, um die Funktion des Transponders bei Schwankungen der Chipimpedanz und variablen Umgebungsparametern zu gewährleisten. Der aus Platzgründen notwendige Einsatz elektrisch kleiner Antennen bedingt eine möglichst optimale Ausnutzung der zur Verfügung stehenden Fläche auf dem Trägermaterial zur Aufnahme der Antenne. Die vorliegende Arbeit beschreibt ein Verfahren zur Analyse und Synthese neuartiger Antennendesigns auf der Basis parametrisierter meandrierter, spiralförmiger und logarithmisch periodischer Dipole.

  3. Schönheit und andere Provokationen - Eine neue evolutionsbiologische Theorie der Kunst

    NASA Astrophysics Data System (ADS)

    Junker, Thomas

    Die Evolution hat viele spektakuläre Phänomene hervorgebracht - von der Eleganz des Vogelflugs über die gigantischen Körper der Dinosaurier und die farbenprächtige Vielfalt der Korallenriffe bis hin zu ihrem jüngsten Geniestreich - der menschlichen Kunst. Die schönen Künste - Malerei, Bildhauerei und Architektur, Theater, Tanz, Oper und Filmkunst, Musik und Literatur - Produkte der Evolution? Diese Vorstellung mutet vielen Menschen fremd an, aber wie könnte es anders sein? Denn wenn Charles Darwin recht hat, dann sind nicht nur die körperlichen Merkmale der Menschen als Antworten auf die Erfordernisse des Lebens entstanden, sondern auch ihre geistigen Fähigkeiten und Verhaltensweisen. Im Jahr 1859 hatte er auf den letzten Seiten seines berühmten Buches über die Entstehung der Arten eine kühne Prophezeiung gemacht: Durch die Evolutionstheorie werde es "zu einer bemerkenswerten Revolution in der Naturwissenschaft kommen […]. Die Psychologie wird auf die neue Grundlage gestellt, dass jede geistige Kraft und Fähigkeit notwendigerweise durch graduelle Übergänge erworben wird“ (Darwin 1859, S. 484, 488; Junker 2008).

  4. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

    NASA Astrophysics Data System (ADS)

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

    2016-03-01

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

  5. Transient disturbance growth in a corrugated channel

    NASA Astrophysics Data System (ADS)

    Szumbarski, J.; Floryan, J. M.

    2006-12-01

    Transient growth of small disturbances may lead to the initiation of the laminar turbulent transition process. Such growth in a two-dimensional laminar flow in a channel with a corrugated wall is analysed. The corrugation has a wavy form that is completely characterized by its wavenumber and amplitude. The maximum possible growth and the form of the initial disturbance that leads to such growth have been identified for each form of the corrugation. The form that leads to the largest growth for a given corrugation amplitude, i.e. the optimal corrugation, has been found. It is shown that the corrugation acts as an amplifier for disturbances that are approximately optimal in the smooth channel case but has little effect in the other cases. The interplay between the modal (asymptotic) instability and the transient growth, and the use of the variable corrugation for modulation of the growth are discussed.

  6. Electromagnetic Counterparts of Gravitational Wave Transients

    NASA Astrophysics Data System (ADS)

    Branchesi, Marica

    2015-03-01

    In the near future the ground-based gravitational wave detectors will reach sensitivities that should make it possible for the first time to directly observe gravitational waves. The simultaneous availability of gravitational wave detectors observing together with space and ground-based electromagnetic telescopes will offer a great opportunity to explore the Universe in a new multi-messenger perspective. Promising sources of gravitational waves are the most energetic astrophysical events such as the merger of neutron stars and/or stellar-mass black holes and the core collapse of massive stars. These events are believed to produce electromagnetic transients in the sky, like gamma-ray bursts and supernovae. An overview of the expected electromagnetic counterparts of the gravitational wave sources is presented, focusing on the challenges, opportunities and strategies for starting transient gravitational wave astronomy.

  7. Characterization of highly transient EUV emitting discharges

    NASA Astrophysics Data System (ADS)

    van der Mullen, Joost; Kieft, Erik; Broks, Bart

    2006-07-01

    The method of disturbed Bilateral Relations (dBR) is used to characterize highly transient plasmas that are used for the generation of Extreme Ultra Violet (EUV), i.e. radiation with a wavelength around 13.5 nm. This dBR method relates equilibrium disturbing to equilibrium restoring processes and follows the degree of equilibrium departure from the global down to the elementary plasma-level. The study gives global values of the electron density and electron temperature. Moreover, it gives a method to construct the atomic state distribution function (ASDF). This ASDF, which is responsible for the spectrum generated by the discharge, is found to be far from equilibrium. There are two reasons for this: first, systems with high charge numbers radiate strongly, second the highly transient behaviour makes that the distribution over the various ionization stages lags behind the temperature evolution.

  8. Transient phenomena in rotary-kiln incineration

    SciTech Connect

    Linak, W.P.; Kilgroe, J.D.; McSorley, J.A.; Wendt, J.O.L.; Dunn, J.E.

    1989-01-01

    This paper describes results of an ongoing experimental investigation at the U.S. EPA into the waste properties and kiln parameters that determine both the instantaneous intensity and the total magnitude of transient puffs leaving the kiln. (NOTE: The batch introduction of waste-filled drums or containers into practical rotary-kiln incinerators can lead to transient overcharging conditions which, for brevity, are here denoted as 'puffs.') The experimental apparatus utilized was a 73-kW laboratory rotary-kiln simulator. Surrogate solid wastes (plastic rods) and surrogate liquid wastes (on corncob sorbent in cardboard containers) were investigated. A statistically designed parametric study was used to determine the extent to which waste and kiln variables (e.g., charge mass, charge surface area, charge composition, kiln temperature, and kiln rotation speed) affected the intensity (hydrocarbon peak height) and magnitude (hydrocarbon peak area) of puffs.

  9. Deflagration transient study of the CIF incinerator

    SciTech Connect

    Hang, T.

    2000-01-03

    The Consolidated Incineration Facility (CIF) treats solid and liquid RCRA hazardous and mixed wastes generated at the Savannah River Site (SRS). The transient responses of the CIF system to a deflagration, caused by an accidental charge of a modest quantity of solvent (e.g. toluene) into the rotary kiln, were a major safety concern. Using a dynamic computer model, a study was conducted to analyze the transient system responses to the rapid temperature and pressure surge in the kiln. The objective of the study was to determined the maximum pressure, temperature, and gas flow rate in each CIF component (rotary kiln, secondary combustion chamber, quencher, scrubber/cyclone, mist eliminator, reheaters, HEPAs, and ID fans). The resulting data provided a basis for the subsequent structural analysis. This paper will describe the CIF deflagration study in some detail, and present the results of the simulation scenarios.

  10. Ultrahigh resolution photoacoustic microscopy via transient absorption

    PubMed Central

    Shelton, Ryan L.; Applegate, Brian E.

    2010-01-01

    We have developed a novel, hybrid imaging modality, Transient Absorption Ultrasonic Microscopy (TAUM), which takes advantage of the optical nonlinearities afforded by transient absorption to achieve ultrahigh-resolution photoacoustic microscopy. The theoretical point spread function for TAUM is functionally equivalent to confocal and two-photon fluorescence microscopy, potentially enabling cellular/subcellular photoacoustic imaging. A prototype TAUM system was designed, built, and used to image a cross-section through several capillaries in the excised cheek pouch of a Syrian Hamster. The well-resolved capillaries in the TAUM image provided experimental evidence of the spatial resolution. These results suggest that TAUM has excellent potential for producing volumetric images with cellular/subcellular resolution in three dimensions deep inside living tissue. PMID:21258499

  11. Transient Pressure Test Article (TPTA) Test Firing

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Marshall Space Flight Center (MSFC) successfully test fired the third in a series of Transient Pressure Test Articles (TPTA) in its east test area. The test article was a short-stack solid rocket motor 52-feet long and 12-feet in diameter. The TPTA tests were designed to evaluate the effects of temperature, pressure and external loads encountered by the SRM, primarily during ignition transients. Instrumentation on the motor recorded approximately 1,000 charnels of data to verify the structural performance, thermal response, sealing capability of the redesign field, and case-to-nozzle joints. The TPTA test stand, 14-feet wide by 26-feet long by 33-feet high, was built in 1987. The TPTA series was a joint effort among Morton Thiokol, Inc., United Space Boosters, Inc., Wyle Laboratories, and MSFC. Wyle Laboratories conducted the tests for the MSFC, which manages the redesigned SRM program for NASA.

  12. Ignition transient analysis of solid rocket motor

    NASA Technical Reports Server (NTRS)

    Han, Samuel S.

    1991-01-01

    Measurement data on the performance of Space Shuttle Solid Rocket Motor show wide variations in the head-end pressure changes and the total thrust build-up during the ignition transient periods. To analyze the flow and thermal behavior in the tested solid rocket motors, a 1-dimensional, ideal gas flow model via the SIMPLE algorithm was developed. Numerical results showed that burning patterns in the star-shaped head-end segment of the propellant and the erosive burning rate are two important factors controlling the ignition transients. The objective of this study is to extend the model to include the effects of aluminum particle commonly used in solid propellants. To treat the effects of aluminum-oxide particles in the combustion gas, conservation of mass, momentum, and energy equations for the particles are added in the numerical formulation and integrated by an inter-phase-slip algorithm.

  13. Transient photothermal spectra of plasmonic nanobubbles.

    PubMed

    Lukianova-Hleb, Ekaterina Y; Sassaroli, Elisabetta; Jones, Alicia; Lapotko, Dmitri O

    2012-03-13

    The photothermal efficacy of near-infrared gold nanoparticles (NP), nanoshells, and nanorods was studied under pulsed high-energy optical excitation in plasmonic nanobubble (PNB) mode as a function of the wavelength and duration of the excitation laser pulse. PNBs, transient vapor nanobubbles, were generated around individual and clustered overheated NPs in water and living cells. Transient PNBs showed two photothermal features not previously observed for NPs: the narrowing of the spectral peaks to 1 nm and the strong dependence of the photothermal efficacy upon the duration of the laser pulse. Narrow red-shifted (relative to those of NPs) near-infrared spectral peaks were observed for 70 ps excitation laser pulses, while longer sub- and nanosecond pulses completely suppressed near-infrared peaks and blue shifted the PNB generation to the visual range. Thus, PNBs can provide superior spectral selectivity over gold NPs under specific optical excitation conditions.

  14. Transient Diabetes Insipidus Following Cardiopulmonary Bypass.

    PubMed

    Ekim, Meral; Ekim, Hasan; Yilmaz, Yunus Keser; Bolat, Ali

    2015-04-01

    Diabetes insipidus (DI) results from inadequate output of Antidiuretic Hormone (ADH) from the pituitary gland (central DI) or the inability of the kidney tubules to respond to ADH (nephrogenic DI). ADH is an octapeptide produced in the supraoptic and paraventricular nuclei of the hypothalamus and stored in the posterior lobe of the pituitary gland. Cardiopulmonary Bypass (CPB) has been shown to cause a six-fold increased circulating ADH levels 12 hours after surgery. However, in some cases, ADH release may be transiently suppressed due to cardioplegia (cardiac standstill) or CPB leading to DI. We present the postoperative course of a 60-year-old man who developed transient DI after CPB. He was successfully treated by applying nasal desmopressin therapy. Relevant biochemical parameters should be monitored closely in patients who produce excessive urine after open heart surgery.

  15. Transient Response of FGM Pressure Vessels

    NASA Astrophysics Data System (ADS)

    Pekel, Hakan; Keles, Ibrahim; Temel, Beytullah; Tutuncu, Naki

    The present study aims to investigate the transient behavior of thick-walled cylinders under dynamic internal pressure. Analytical solutions are possible only for simple time-dependent pressure functions. The solution procedure presented is general in the sense that the pressure applied may be an arbitrary continuous function of time, impulsive or given in a discrete form. The material considered is isotropic and heterogeneous with properties varying in the radial direction termed as Functionally Graded Material (FGM). Laplace transform method is used and the inversion into the time domain is performed using the modified Durbin's method. Verification of the numerical procedure is performed by comparing the results with those of an analytical solution available in the literature for a simple exponentially-varying pressure. The inhomogeneity constant in the material property model is shown to have a significant effect on the transient response.

  16. Steady and transient regimes in hydropower plants

    NASA Astrophysics Data System (ADS)

    Gajic, A.

    2013-12-01

    Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

  17. Transient One-dimensional Pipe Flow Analyzer

    SciTech Connect

    1986-04-08

    TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and various form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.

  18. A physically transient form of silicon electronics.

    PubMed

    Hwang, Suk-Won; Tao, Hu; Kim, Dae-Hyeong; Cheng, Huanyu; Song, Jun-Kyul; Rill, Elliott; Brenckle, Mark A; Panilaitis, Bruce; Won, Sang Min; Kim, Yun-Soung; Song, Young Min; Yu, Ki Jun; Ameen, Abid; Li, Rui; Su, Yewang; Yang, Miaomiao; Kaplan, David L; Zakin, Mitchell R; Slepian, Marvin J; Huang, Yonggang; Omenetto, Fiorenzo G; Rogers, John A

    2012-09-28

    A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via resorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon-based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system-level example.

  19. Sprites, elf transients, and positive ground strokes

    SciTech Connect

    Boccippio, D.J.; Boldi, R.; Williams, E.R.

    1995-08-25

    In two summertime mesoscale convective systems (MCSs), mesospheric optical sprite phenomena were often coincident with both large-amplitude positive cloud-to-ground lightning and transient Schumann resonance excitations of the entire Earth-ionosphere cavity. These observations, together with earlier studies of MCS electrification, suggest that sprites are triggered when the rapid removal of large quantities of positive charge from an areally extensive charge layer stresses the mesosphere to dielectric breakdown. 46 refs., 7 figs., 1 tab.

  20. Transient Cognitive Dynamics, Metastability, and Decision Making

    DTIC Science & Technology

    2008-05-02

    793–810. 39. Wagatsuma H, Yamaguchi Y (2007) Neural dynamics of the cognitive map in the hippocampus. Cognitive Neurodynamics 1: 119–141. 40. Kifer Y...Transient Cognitive Dynamics, Metastability, and Decision Making Mikhail I. Rabinovich1*, Ramón Huerta1,2, Pablo Varona2, Valentin S. Afraimovich3 1...Óptica, UASLP, San Luis de Potosı́, Mexico Abstract The idea that cognitive activity can be understood using nonlinear dynamics has been intensively

  1. ATLAS discovery of an optical transient

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-08-01

    We report the following transient found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  2. Validity of Darcy's law under transient conditions

    USGS Publications Warehouse

    Mongan, C.E.

    1985-01-01

    Darcy 's Law, which describes fluid flow through porous materials, was developed for steady flow conditions. The validity of applying this law to transient flows has been mathematically verified for most ground-water flow conditions. The verification was accomplished through application of Hankel transforms to linearized Navier-Stokes equations which described flow in a small diameter cylindrical tube. The tube was chosen to represent a single pore in a porous medium. (USGS)

  3. Monitoring transients in low inductance circuits

    DOEpatents

    Guilford, R.P.; Rosborough, J.R.

    1985-10-21

    The instant invention relates to methods of and apparatus for monitoring transients in low inductance circuits and to a probe utilized to practice said method and apparatus. More particularly, the instant invention relates to methods of and apparatus for monitoring low inductance circuits, wherein the low inductance circuits include a pair of flat cable transmission lines. The instant invention is further directed to a probe for use in monitoring pairs of flat cable transmission lines.

  4. Transient Pressure Test Article test program

    NASA Technical Reports Server (NTRS)

    Vibbart, Charles M.

    1988-01-01

    The Transient Pressure Test Article test program being conducted at NASA-Marshall is described. The main goal of the TPTA test program is to provide data to verify the sealing capability of the redesigned SRM field joints, the nozzle-to-case joint, and the igniter joint. The TPTA test program can be used to demonstrate the assembly/disassembly and reusability of the redesigned joints along with the adequacy of assembly/disassembly tooling, procedures, and inspections.

  5. Transient Model for Keyhole During Laser Welding

    SciTech Connect

    Bragg, W.D.; Damkroger, B.; Kempka, S.; Semak, V.V.

    1999-03-05

    A novel approach to simulating the dominant dynamic processes present during concentrated energy beam welding of metals is presented. A model for transient behavior of the front keyhole wall is developed. It is assumed that keyhole propagation is dominated by evaporation recoil-driven melt expulsion from the beam interaction zone. Results from the model show keyhole instabilities consistent with experimental observations of metal welding, metal cutting and ice welding.

  6. Coherent Transient Effect Studies of Rydberg Atoms.

    DTIC Science & Technology

    1982-09-01

    occurs in a Rydberg gas at the densities requil for transient experiments (NA1.2 atoms/cmut). The-decay process was studied using ion collection and...rather than in the visible. Although experiments with (visible) tunable dye lasers are therefore not possible, one can use powerful, stable cw...construction of atomic Rydberg lasers, the use of Rydberg atoms as high-sensitivity microwave detectors (already demonstrated by Figger et al), 14 and

  7. Transient Analysis of X-34 Pressurization System

    NASA Technical Reports Server (NTRS)

    Hedayat, A.; Knight, K. C.; Champion, R. H., Jr.

    1998-01-01

    Two transient operational modes of the X-34 pressurization system were analyzed using the ROCket Engine Transition Simulation (ROCETS) program. The first operational mode considers the normal operation. For the engine burn period, the required helium mass and pressure of each propellant tank were calculated. In the second case, the possibility of failure of the pressurization system solenoid valves, its consequence on the over-pressurization, and simultaneous operation of pressurization and vent/relief systems were evaluated.

  8. iPTF report of bright transients

    NASA Astrophysics Data System (ADS)

    Cannella, Chris; Kuesters, Daniel; Ferretti, Raphael; Blagorodnova, Nadejda; Adams, Scott; Kupfer, Thomas; Neill, James D.; Walters, Richard; Yan, Lin; Kulkarni, Shri

    2017-02-01

    The intermediate Palomar Transient Factory (iPTF; ATel #4807) reports the following bright ( Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R), and RB5 (Wozniak et al. 2013AAS...22143105W).

  9. Reactivity Transients in Nuclear Research Reactors

    SciTech Connect

    2015-01-01

    Version 01 AIREMOD-RR is a point kinetics code which can simulate fast transients in nuclear research reactor cores. It can also be used for theoretical reactor dynamics studies. It is used for research reactor kinetic analysis and provides a point neutron kinetic capability. The thermal hydraulic behavior is governed by a one-dimensional heat balance equation. The calculations are restricted to a single equivalent unit cell which consists of fuel, clad and coolant.

  10. TRANSIENT SOUNDING INVESTIGATION OF NEWBERRY VOLCANO, OREGON.

    USGS Publications Warehouse

    Fitterman, David V.; Neev, Deborah K.

    1985-01-01

    Transient electromagnetic soundings were used to map the geoelectrical structure of Newberry Volcano in central Oregon. An extensive conductor was found to underlie the volcano and to have resistivities from 20 OMEGA m to 72 OMEGA m. The depth to the conductor ranges from 410 m to 870 m. Inside the caldera, low basement resistivities are the result of hot fluids. The cause of the conductor outside the caldera is not known; however, we speculate that it is due to the water table.

  11. Transient Thermal Stability of Polymer Nanocomposites

    DTIC Science & Technology

    2012-08-01

    Temperatures exceed melting point and degradation temp of base polymer • Nanoclay and Nanotubes provide degradation resistance • Novel TGA-LPH...difference in heating rate 0 500 1000 1500 2000 0 4 8 12 time (ms) S u rf a c e t e m p e ra tu re ( K ) 120mm cannon Use polypropylene as a model...system to investigate degradation kinetics during transient heating Goal of this project Materials Isotactic Polypropylene + 0-50 wt % nanoclay

  12. Nonlinear transient analysis via energy minimization

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.; Knight, N. F., Jr.

    1978-01-01

    The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose.

  13. Transient dynamics for sequence processing neural networks

    NASA Astrophysics Data System (ADS)

    Kawamura, Masaki; Okada, Masato

    2002-01-01

    An exact solution of the transient dynamics for a sequential associative memory model is discussed through both the path-integral method and the statistical neurodynamics. Although the path-integral method has the ability to give an exact solution of the transient dynamics, only stationary properties have been discussed for the sequential associative memory. We have succeeded in deriving an exact macroscopic description of the transient dynamics by analysing the correlation of crosstalk noise. Surprisingly, the order parameter equations of this exact solution are completely equivalent to those of the statistical neurodynamics, which is an approximation theory that assumes crosstalk noise to obey the Gaussian distribution. In order to examine our theoretical findings, we numerically obtain cumulants of the crosstalk noise. We verify that the third- and fourth-order cumulants are equal to zero, and that the crosstalk noise is normally distributed even in the non-retrieval case. We show that the results obtained by our theory agree with those obtained by computer simulations. We have also found that the macroscopic unstable state completely coincides with the separatrix.

  14. Transient birefringence effects in electromagnetically induced transparency

    SciTech Connect

    Parshkov, O M

    2015-11-30

    We report the results of numerical modelling of transient birefringence that arises as a result of electromagnetically induced transparency on degenerate quantum transitions between the states with J = 0, 1 and 2 in the presence of the Doppler broadening of spectral lines. It is shown that in the case of a linearly polarised control field, the effect of transient birefringence leads to a decay of the input circularly polarised probe pulse into separate linearly polarised pulses inside a medium. In the case of a circularly polarised control field, the effect of transient birefringence manifests itself in a decay of the input linearly polarised probe pulse into separate circularly polarised pulses. It is shown that the distance that a probe pulse has to pass in a medium before decaying into subpulses is considerably greater in the first case than in the second. The influence of the input probe pulse power and duration on the process of spatial separation into individual pulses inside a medium is studied. A qualitative analysis of the obtained results is presented. (nonlinear optical phenomena)

  15. Imaging transient events at high angular resolution

    NASA Astrophysics Data System (ADS)

    Schaefer, Gail H.

    2016-08-01

    Resolving the spatial structure of transient events provides insights into their physical nature and origin. Recent observations using long baseline optical/infrared interferometry have revealed the size, shape, and angular expansion of bright novae within a few days after their outbursts. This has implications for understanding the timescale for the development of asymmetric features in novae ejecta. Additionally, combining spectroscopic measurements of the expansion velocity with the angular expansion rate provides a way to measure a geometric distance to the nova. In this paper, I provide a review of interferometric observations of novae, with a focus on recent results on the expansion and spatial structure of nova V339 Del in 2013. I also discuss other promising applications of interferometry to transient sources, such as measuring the image size and centroid displacements to measure planetary masses in gravitational microlensing events. Given the timescales of transient events, it is critical for interferometric arrays to respond rapidly to targets of opportunity in order to optimize the instrumental sensitivity and baselines required to resolve the source while its brightness and size change over time.

  16. Aeroelastic Modeling of a Nozzle Startup Transient

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  17. Transient selection in multicellular immune networks

    NASA Astrophysics Data System (ADS)

    Ivanchenko, M. V.

    2011-03-01

    We analyze the dynamics of a multi-clonotype naive T-cell population competing for survival signals from antigen-presenting cells. We find that this competition provides with an efficacious selection of clonotypes, making the less able and more repetitive get extinct. We uncover the scaling principles for large systems the extinction rate obeys and calibrate the model parameters to their experimental counterparts. For the first time, we estimate the physiological values of the T-cell receptor-antigen presentation profile recognition probability and T-cell clonotypes niche overlap. We demonstrate that, while the ultimate state is a stable fixed point, sequential transients dominate the dynamics over large timescales that may span over years, if not decades, in real time. We argue that what is currently viewed as "homeostasis" is a complex sequential transient process, while being quasi-stationary in the total number of T-cells only. The discovered type of sequential transient dynamics in large random networks is a novel alternative to the stable heteroclinic channel mechanism.

  18. Transient Peripapillary Retinoschisis in Glaucomatous Eyes

    PubMed Central

    Vermeer, Koenraad A.; Lemij, Hans G.

    2017-01-01

    Purpose. To investigate transient focal microcystic retinoschisis in glaucomatous eyes in images obtained with several imaging techniques used in daily glaucoma care. Methods. Images of 117 glaucoma patients and 91 healthy subjects participating in a large prospective follow-up study into glaucoma imaging were reviewed. Participants were measured with spectral domain optical coherence tomography (SD-OCT), scanning laser polarimetry (SLP), scanning laser tomography (SLT), and standard automated perimetry (SAP). The presence of a focal retinoschisis in SD-OCT was observed and correlated to SLP, SLT, and SAP measurements, both cross-sectionally and longitudinally. Results. Seven out of 117 glaucoma patients showed a transient, localised, peripapillary, heterogeneous microcystic schisis of the retinal nerve fiber layer (RNFL) and sometimes other retinal layers as well in SD-OCT. None of the healthy eyes showed this phenomenon nor did any of the other imaging techniques display it as detailed and consistently as did the SD-OCT. SAP showed a temporarily decreased focal retinal sensitivity during the retinoschisis and we found no signs of glaucomatous progression related to the retinoschisis. Conclusions. Transient microcystic retinoschisis appears to be associated with glaucomatous wedge defects in the RNFL. It was best observed with SD-OCT and it was absent in healthy eyes. We found no evidence that the retinoschisis predicted glaucomatous progression. PMID:28168045

  19. Transient eddies in the MACDA Mars reanalysis

    NASA Astrophysics Data System (ADS)

    Mooring, Todd A.; Wilson, R. John

    2015-10-01

    We present a survey of the transient eddy activity in the Mars Analysis Correction Data Assimilation (MACDA) reanalysis. The spatial structure and propagation characteristics of the eddies are emphasized. Band-pass-filtered variance and covariance fields are found to be zonally modulated, indicating a longitude dependence of the typical amplitudes of Martian transient eddies. Considerable repeatability of the eddy field spatial structures is found across Mars years, including a roughly wave number 3 pattern of low-level eddy meridional temperature transport (v'T'¯) in the northern hemisphere that is evident before and after winter solstice and a possible tendency for northern hemisphere eddy kinetic energy maxima to be located above low-lying areas. Southern hemisphere eddy fields tend to feature two local maxima, one roughly south of Tharsis and the other associated with Hellas. Eddies are weakened near winter solstice in both hemispheres and were generally weakened in the northern hemisphere during the 2001 (Mars year 25) global dust storm, albeit with little change in spatial patterns. Because the transient eddies propagate in space, we also used a teleconnection map-based technique to estimate their phase velocities. Eddy propagation at the surface is found to follow topography, a phenomenon less evident at higher altitude. Possible physical mechanisms underlying the documented eddy phenomena are discussed.

  20. TRANSIENT AMORPHOUS CALCIUM PHOSPHATE IN FORMING ENAMEL

    PubMed Central

    Beniash, Elia; Metzler, Rebecca A.; Lam, Raymond S.K.; Gilbert, P.U.P.A.

    2009-01-01

    Enamel, the hardest tissue in the body, begins as a three-dimensional network of nanometer size mineral particles, suspended in a protein gel. This mineral network serves as a template for mature enamel formation. To further understand the mechanisms of enamel formation we characterized the forming enamel mineral at an early secretory stage using x-ray absorption near-edge structure (XANES) spectromicroscopy, transmission electron microscopy (TEM), FTIR microspectroscopy and polarized light microscopy. We show that the newly formed enamel mineral is amorphous calcium phosphate (ACP), which eventually transforms into apatitic crystals. Interestingly, the size, shape and spatial organization of these amorphous mineral particles and older crystals are essentially the same, indicating that the mineral morphology and organization in enamel is determined prior to its crystallization. Mineralization via transient amorphous phases has been previously reported in chiton teeth, mollusk shells, echinoderm spicules and spines, and recent reports strongly suggest the presence transient amorphous mineral in forming vertebrate bones. The present finding of transient ACP in murine tooth enamel suggests that this strategy might be universal. PMID:19217943

  1. Transient Clumps in Saturn's F Ring

    NASA Astrophysics Data System (ADS)

    Meinke, B. K.; Esposito, L. W.; Sremcevic, M.

    2011-10-01

    The Cassini Ultraviolet Imaging Spectrograph has detected 27 statistically significant features in 101 occultations by Saturn's F ring since July 2004. Of those 27 features, 17 likely correspond to transient clumps of material. We calculate from these observations the total number and total mass of transient clumps in the F ring. Constraints from observations place an upper limit on the number and total mass of such clumps. In turn, an upper limit on mass indicates that the clumps are not solid, spherical objects, rather they are loosely-packed, triaxial ellipsoids elongated in azimuth and vertically flattened. The total mass of clumps in the F ring is thus 6.1 x 1014 kg, the equivalent of a 6.8 km icy moon with a density equivalent to that of Prometheus. The differences in optical depth and morphology of the 17 significant features considered here also lead us to believe porosity differences exist among clumps. We investigate how the size distribution of clumps of different porosities evolves and how compaction of such clumps could lead to denser states that resemble moonlets, which describes 2 of the 17 features observed. The results presented here lead to a better model of how transient clumps form, evolve, and survive.

  2. Magnetic Flux Transients during Solar Flares

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, K. S.; Delgado, F.; Hock, R. A.

    2013-12-01

    Solar flares result from the sudden release of energy stored in the magnetic field of the solar atmosphere, attributed to magnetic reconnection. In this work, we use line-of-sight magnetograms to study the changes in photospheric magnetic field during large solar flares. The magnetograms are derived from observations using NASA's Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory, and have a cadence of 3 minutes at a 0.5 arcsecond spatial resolution. We studied the inferred magnetic flux changes in 11 X-class flares from (2011-2012) and 26 M-class flares (2011). Of the 37 flares, 32 exhibited short-lived (less than 30 minutes) magnetic flux transients (MFTs) during the progress of the flare, similar to those by Maurya et al. (2012). We note that MFTs were co-temporal with GOES X-ray peaks. Flares with rapid rises (impulsive flares) had stronger transients while those with slower rises (gradual flares) had weak or no MFTs. Finally, flares with stronger GOES X-ray peaks (flare class) showed stronger MFTs. We believe that these changes are non-physical because the changes in the magnetic field are transient (the magnetic field returns to the pre-flare state) and coincide with the impulsive phase of the flare. This work supported by the US Airforce Office of Scientific Research and the AFRL/RV Space Scholar Program.

  3. Cometary Impacts Produce Transient Atmospheres on Charon

    NASA Astrophysics Data System (ADS)

    Stern, S. A.; Gladstone, R.

    2013-10-01

    Introduction: Although Charon’s H2O-ice surface has long suggested a lack of a permanent atmosphere (e.g., Stern et al. 1988), impacts from KBO comets must import N2, CO, CH4, and other cometary super-volatiles that create temporary atmospheres around Charon from time to time. Impacts may also excavate volatiles below Charon’s surface, also sourcing transient atmospheres. Synopsis: In this report we estimate the frequency of cometary impacts on Charon and the imported mass of super-volatiles from each such impact, finding a mean time between impacts of d=1 km comets to be of order 1x106 years. We then examine certain characteristics of such atmospheric transients, including their expected column densities, scale heights, loss timescales, and dynamical regimes. We then evaluate the detectability of such transient atmospheres by the Alice UV spectrograph aboard New Horizons. References: Stern, S.A., Trafton, L.M., and Gladstone, G.R., 1988. Icarus, 75, 485-498.

  4. Experimental Investigation of Transient Sublimator Performance

    NASA Technical Reports Server (NTRS)

    Sheth, Rubik B.; Stephan, Ryan A.; Leimkuehler, Thomas O.

    2012-01-01

    Sublimators have been used as heat rejection devices for a variety of space applications including the Apollo Lunar Module and the Extravehicular Mobility Unit (EMU). Sublimators typically operate with steady-state feedwater utilization at or near 100%. However, sublimators are currently being considered for operations in a cyclical topping mode, which represents a new mode of operation for sublimators. Sublimators can be used as a supplemental heat rejection device during mission phases where the environmental temperature or heat rejection requirement changes rapidly. This scenario may occur during low lunar orbit, low earth orbit, or other planetary orbits. In these mission phases, the need for supplemental heat rejection will vary between zero and some fraction of the overall heat load. In particular, supplemental heat rejection is required for the portion of the orbit where the radiative sink temperature exceeds the system setpoint temperature. This paper will describe the effects of these transient starts and stops on the feedwater utilization during various feedwater timing scenarios. Experimental data from various scenarios is analyzed to investigate feedwater consumption efficiency under the cyclical conditions. Start up utilization tests were conducted to better understand the transient performance. This paper also provides recommendations for future sublimator design and transient operation.

  5. Transient Thermoelectric Solution Employing Green's Functions

    NASA Technical Reports Server (NTRS)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    The study works to formulate convenient solutions to the problem of a thermoelectric couple operating under a time varying condition. Transient operation of a thermoelectric will become increasingly common as thermoelectric technology permits applications in an increasing number of uses. A number of terrestrial applications, in contrast to steady-state space applications, can subject devices to time varying conditions. For instance thermoelectrics can be exposed to transient conditions in the automotive industry depending on engine system dynamics along with factors like driving style. In an effort to generalize the thermoelectric solution a Greens function method is used, so that arbitrary time varying boundary and initial conditions may be applied to the system without reformulation. The solution demonstrates that in thermoelectric applications of a transient nature additional factors must be taken into account and optimized. For instance, the materials specific heat and density become critical parameters in addition to the thermal mass of a heat sink or the details of the thermal profile, such as oscillating frequency. The calculations can yield the optimum operating conditions to maximize power output andor efficiency for a given type of device.

  6. Probabilistic projections of transient climate change

    NASA Astrophysics Data System (ADS)

    Harris, Glen R.; Sexton, David M. H.; Booth, Ben B. B.; Collins, Mat; Murphy, James M.

    2013-06-01

    This paper describes a Bayesian methodology for prediction of multivariate probability distribution functions (PDFs) for transient regional climate change. The approach is based upon PDFs for the equilibrium response to doubled carbon dioxide, derived from a comprehensive sampling of uncertainties in modelling of surface and atmospheric processes, and constrained by multiannual mean observations of recent climate. These PDFs are sampled and scaled by global mean temperature predicted by a Simple Climate Model (SCM), in order to emulate corresponding transient responses. The sampled projections are then reweighted, based upon the likelihood that they correctly replicate observed historical changes in surface temperature, and combined to provide PDFs for 20 year averages of regional temperature and precipitation changes to the end of the twenty-first century, for the A1B emissions scenario. The PDFs also account for modelling uncertainties associated with aerosol forcing, ocean heat uptake and the terrestrial carbon cycle, sampled using SCM configurations calibrated to the response of perturbed physics ensembles generated using the Hadley Centre climate model HadCM3, and other international climate model simulations. Weighting the projections using observational metrics of recent mean climate is found to be as effective at constraining the future transient response as metrics based on historical trends. The spread in global temperature response due to modelling uncertainty in the carbon cycle feedbacks is determined to be about 65-80 % of the spread arising from uncertainties in modelling atmospheric, oceanic and aerosol processes of the climate system. Early twenty-first century aerosol forcing is found to be extremely unlikely to be less than -1.7 W m-2. Our technique provides a rigorous and formal method of combining several lines of evidence used in the previous IPCC expert assessment of the Transient Climate Response. The 10th, 50th and 90th percentiles of our

  7. Transients in reactors for power systems compensation

    NASA Astrophysics Data System (ADS)

    Abdul Hamid, Haziah

    This thesis describes new models and investigations into switching transient phenomena related to the shunt reactors and the Mechanically Switched Capacitor with Damping Network (MSCDN) operations used for reactive power control in the transmission system. Shunt reactors and MSCDN are similar in that they have reactors. A shunt reactor is connected parallel to the compensated lines to absorb the leading current, whereas the MSCDN is a version of a capacitor bank designed as a C-type filter for use in the harmonic-rich environment. In this work, models have been developed and transient overvoltages due to shunt reactor deenergisation were estimated analytically using MathCad, a mathematical program. Computer simulations used the ATP/EMTP program to reproduce both single-phase and three-phase shunt reactor switching at 275 kV operational substations. The effect of the reactor switching on the circuit breaker grading capacitor was also examined by considering various switching conditions.. The main original achievement of this thesis is the clarification of failure mechanisms occurring in the air-core filter reactor due to MSCDN switching operations. The simulation of the MSCDN energisation was conducted using the ATP/EMTP program in the presence of surge arresters. The outcome of this simulation shows that extremely fast transients were established across the air-core filter reactor. This identified transient event has led to the development of a detailed air-core reactor model, which accounts for the inter-turn RLC parameters as well as the stray capacitances-to-ground. These parameters are incorporated into the transient simulation circuit, from which the current and voltage distribution across the winding were derived using electric field and equivalent circuit modelling. Analysis of the results has revealed that there are substantial dielectric stresses imposed on the winding insulation that can be attributed to a combination of three factors. (i) First, the

  8. Transient Numerical Modeling of Catalytic Channels

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    This paper presents a transient model of catalytic combustion suitable for isolated channels and monolith reactors. The model is a lumped two-phase (gas and solid) model where the gas phase is quasi-steady relative to the transient solid. Axial diffusion is neglected in the gas phase; lateral diffusion, however, is accounted for using transfer coefficients. The solid phase includes axial heat conduction and external heat loss due to convection and radiation. The combustion process utilizes detailed gas and surface reaction models. The gas-phase model becomes a system of stiff ordinary differential equations while the solid phase reduces, after discretization, into a system of stiff ordinary differential-algebraic equations. The time evolution of the system came from alternating integrations of the quasi-steady gas and transient solid. This work outlines the numerical model and presents some sensitivity studies on important parameters including internal transfer coefficients, catalytic surface site density, and external heat-loss (if applicable). The model is compared to two experiments using CO fuel: (1) steady-state conversion through an isothermal platinum (Pt) tube and (2) transient propagation of a catalytic reaction inside a small Pt tube. The model requires internal mass-transfer resistance to match the experiments at lower residence times. Under mass-transport limited conditions, the model reasonably predicted exit conversion using global mass-transfer coefficients. Near light-off, the model results did not match the experiment precisely even after adjustment of mass-transfer coefficients. Agreement improved for the first case after adjusting the surface kinetics such that the net rate of CO adsorption increased compared to O2. The CO / O2 surface mechanism came from a sub-set of reactions in a popular CH4 / O2 mechanism. For the second case, predictions improved for lean conditions with increased external heat loss or adjustment of the kinetics as in the

  9. Transient Sub-Poissonian Distribution for Single-Mode Lasers

    NASA Technical Reports Server (NTRS)

    Zang, J. Y.; Gu, Q.; Tian, L. K.

    1996-01-01

    In this paper, the transient photon statistics for single-mode lasers is investigated by making use of the theory of quantum electrodynamics. By taking into account of the transitive time l,we obtain the master equation for Jaynes-Cummings model. The relation between the Mandel factor and the time is obtained by directly solving the master equation. The result shows that a transient phenomenon from the transient super-Poissonian distribution to the transient sub-Poissonian distribution occurs for single-mode lasers. In addition, the influences of the thermal light field and the cavity loss on the transient sub-Poissonian distribution are also studied.

  10. Fragwuerdige Luxussteuern: Statusstreben und Demonstratives Konsumverhalten in der Geschichte Oekonomischen Denkens (Questionable Luxury Taxes: Status Seeking and Conspicuous Consumption in the History of Economic Thought)

    DTIC Science & Technology

    2008-05-01

    England immer mehr, und der Markt ffir Luxusgiiter und Mode begann zu florieren. Die Kommerzialisierung des Handels im England des 18. Jahrhunderts...der insbesondere Hirsch (1976) in seinen Social Limits to Growth wieder Nachdruck verleihen sollte. Siehe hierzu Abschnitt 2.9. 5 auf seinen...klassischen Schule ibertriebenes statusbedingtes Konsumverhalten als social waste an und pladiert fdr eine Lenkung statusbedingten Konsumverhaltens in

  11. Transient fault behavior in a microprocessor: A case study

    NASA Technical Reports Server (NTRS)

    Duba, Patrick

    1989-01-01

    An experimental analysis is described which studies the susceptibility of a microprocessor based jet engine controller to upsets caused by current and voltage transients. A design automation environment which allows the run time injection of transients and the tracing from their impact device to the pin level is described. The resulting error data are categorized by the charge levels of the injected transients by location and by their potential to cause logic upsets, latched errors, and pin errors. The results show a 3 picoCouloumb threshold, below which the transients have little impact. An Arithmetic and Logic Unit transient is most likely to result in logic upsets and pin errors (i.e., impact the external environment). The transients in the countdown unit are potentially serious since they can result in latched errors, thus causing latent faults. Suggestions to protect the processor against these errors, by incorporating internal error detection and transient suppression techniques, are also made.

  12. Explorer for Transient Astrophysics: an X-ray transient mission for the 2020s

    NASA Astrophysics Data System (ADS)

    Camp, Jordan

    2016-04-01

    Explorer for Transient Astrophysics (ETA) is a wide-field X-ray transient mission proposed for flight starting in 2023. Through its unique imaging X-ray optics that allow a 30 deg by 20 deg FoV in three separate modules, a 1 arc min position resolution and a 10-11 erg/(sec cm2) sensitivity in 2000 sec, ETA will observe numerous events per year of X-ray transients related to compact objects, including: tidal disruptions of stars, supernova shock breakouts, neutron star bursts and superbursts, high redshift Gamma-Ray Bursts, and perhaps most exciting, X-ray counterparts of gravitational wave detections involving stellar mass and possibly supermassive black holes. The mission includes an IR Telescope that allows on-board redshift determination of gamma-ray bursts, and a small gamma-ray burst monitor to be contributed by the Technion (Israel Institute of Technology.)

  13. Transient Pressure Test Article Test Program

    NASA Technical Reports Server (NTRS)

    Vibbart, Charles M.

    1989-01-01

    The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

  14. Detection of Transient Signals from Extraterrestrial Technologies

    NASA Astrophysics Data System (ADS)

    Tarter, J. C.

    2003-05-01

    If you were an engineer and wanted to build a beacon with which to attract the attention of any emerging technological civilizations in the Milky Way galaxy, how would you do it? SETI 2020: A Roadmap for the Search for Extraterrestrial Intelligence (a recent report of the SETI Science and Technology Working Group) describes a number of different beacon scenarios, as well as examples of leakage radiation, all of which would lead to signal types that appear as transients in the sky of any given receiving civilization. Most SETI searches to date have been ill-matched to the problem of finding transient signals; the dwell time on source has been short, and the same directions have not been revisited very often. Both the Omnidirectional SETI System (OSS) proposed in SETI 2020, and the Allen Telescope Array (ATA) will offer greatly improved opportunities for detecting radio transients, whether they are from technological or astrophysical sources. The ATA should be operational within a few years, but the OSS will not be affordable until Moore's Law has significantly reduced the cost for the compute power needed to form all beams on the sky and all frequency channels in the spectrometers. This is estimated to be { ˜ 1016}-10{21} ops depending on the total collecting area of the array. Nevertheless, the opportunity to build a radio-fly's-eye or radio camera (suggested by Robert Dixon in 1988) is now getting close enough to warrant prototyping and construction of small size arrays and receivers; several programs are underway.

  15. Sleep Modifications in Acute Transient Global Amnesia

    PubMed Central

    Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

    2013-01-01

    Study Objective: Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events (“minor stroke” or transient ischemic attack [TIA]) clinically and neuroradiologically “similar” to the TGA. Methods: TGA group: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. Results: In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Conclusions: Microstructural modification associated with TGA could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress. Citation: Della Marca G; Mazza M; Losurdo A; Testani E; Broccolini A; Frisullo G; Marano G; Morosetti R; Pilato F; Profice P; Vollono C; Di Lazzaro V. Sleep modifications in acute transient global amnesia. J Clin Sleep Med 2013;9(9):921-927. PMID:23997704

  16. Modeling seismic swarms triggered by aseismic transients

    NASA Astrophysics Data System (ADS)

    Llenos, Andrea L.; McGuire, Jeffrey J.; Ogata, Yosihiko

    2009-04-01

    The rate of earthquake occurrence varies by many orders of magnitude in a given region due to variations in the stress state of the crust. Our focus here is on variations in seismicity rate triggered by transient aseismic processes such as fluid flow, fault creep or magma intrusion. While these processes have been shown to trigger earthquakes, converting observed seismicity variations into estimates of stress rate variations has been challenging. Essentially aftershock sequences often obscure changes in the background seismicity rate resulting from aseismic processes. Two common approaches for estimating the time dependence of the underlying driving mechanisms are the stochastic Epidemic Type Aftershock Sequence model (ETAS) [Ogata, Y., (1988), Statistical models for earthquake occurrences and residual analysis for point processes, J. Am. Stat. Assoc., 83, 9-27.] and a physical approach based on the rate- and state-model of fault friction [Dieterich, J., (1994), A constitutive law for rate of earthquake production and its application to earthquake clustering, J. Geophys. Res., 99, 2601-2618.]. The models have different strengths that could be combined to allow more quantitative studies of earthquake triggering. To accomplish this, we identify the parameters that relate to one another in the two models and examine their dependence on stressing rate. A particular conflict arises because the rate-state model predicts that aftershock productivity scales with stressing rate while the ETAS model assumes that it is time independent. To resolve this issue, we estimate triggering parameters for 4 earthquake swarms contemporaneous with geodetically observed deformation transients in various tectonic environments. We find that stressing rate transients increase the background seismicity rate without affecting aftershock productivity. We then specify a combined model for seismicity rate variations that will allow future studies to invert seismicity catalogs for variations in

  17. Blade loss transient dynamic analysis of turbomachinery

    NASA Technical Reports Server (NTRS)

    Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

    1982-01-01

    This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

  18. Emittance growth from transient coherent synchrotron radiation

    SciTech Connect

    Bohn, C.L.; Li, R.; Bisognano, J.J.

    1996-10-01

    If the energies of individual particles in a bunch change as the bunch traverses a bending system, even if it is achromatic, betatron oscillations can be excited. Consequently, the transverse emittance of the bunch will grow as it moves downstream. Short bunches may be particularly susceptible to emission of coherent synchrotron radiation which can act back on the particles to change their energies and trajectories. Because a bend spans a well-defined length and angle, the bunch-excited wakefield and its effect back on the bunch are inherently transient. We outline a recently developed theory of this effect and apply it to example bending systems.

  19. Propagation of transients in a random medium

    NASA Technical Reports Server (NTRS)

    Wenzel, A. R.

    1975-01-01

    The propagation of transient scalar waves in a three-dimensional random medium is considered. The analysis is based on the smoothing method. An integro-differential equation for the coherent (or average) wave is derived and solved for the case of a statistically homogeneous and isotropic medium and a delta-function source. This yields the coherent Green's function of the medium. It is found that the waveform of the coherent wave depends generally on the distance from the source measured in terms of a certain dimensionless parameter. Based on the magnitude of this parameter, three propagation zones, called the near zone, the far zone, and the intermediate zone, are defined.

  20. Contrast-induced transient cortical blindness.

    PubMed

    Shah, Parth R; Yohendran, Jayshan; Parker, Geoffrey D; McCluskey, Peter J

    2013-05-01

    We present a case of transient cortical blindness secondary to contrast medium toxicity. A 58-year-old man had successful endovascular coiling of a right posterior inferior cerebellar artery aneurysm but became confused and unable to see after the procedure. His visual acuity was no light perception bilaterally. Clinically, there was no new intra-ocular pathology. An urgent non-contrast computed tomography scan of the brain showed cortical hyperdensity in both parieto-occipital cortices, consistent with contrast medium leakage through the blood-brain barrier from the coiling procedure. The man remained completely blind for 72 hours, after which his visual acuity improved gradually back to his baseline level.

  1. Extrapontine myelinolysis resulting in transient cortical blindness.

    PubMed

    Langer, Jennifer E; Wilson, William G; Raghavan, Prashant; Rust, Robert S; Goodkin, Howard P

    2010-02-01

    Central pontine myelinolysis and extrapontine myelinolysis are characterized by symmetric demyelination subsequent to rapid shifts in serum osmolality. Described here is a novel case of transient cortical blindness in association with imaging features of extrapontine myelinolysis, which occurred in a child with carbamoyl phosphate synthetase deficiency after rapid correction of hyperammonemia. Serum sodium levels were within normal limits at presentation and throughout the period of ammonia correction. A potential pathogenic mechanism of osmotic demyelination in the setting of acute treatment for hyperammonemia in a patient with a urea cycle abnormality includes disruption of the blood-brain barrier and re-equilibration of organic osmolytes, particularly glutamine.

  2. Three Decades of Explosive High Energy Transients

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2013-01-01

    Gamma-Ray Bursts are the most brilliant explosions in space. The first GRB was discovered on 1967, just 40 years ago. It took several years and multiple generations of space and ground instruments to unravel some of the mysteries of this phenomenon. However, many questions remain open today. I will discuss the history, evolution and current status of the GRB field and its contributions in our understanding of the transient high energy sky. Finally, I will describe how GRBs can be utilized in future missions as tools, to probe the cosmic chemical evolution of the Universe and the star formation rates.

  3. Transient absorption spectroscopy of laser shocked explosives

    SciTech Connect

    Mcgrane, Shawn D; Dang, Nhan C; Whitley, Von H; Bolome, Cindy A; Moore, D S

    2010-01-01

    Transient absorption spectra from 390-890 nm of laser shocked RDX, PETN, sapphire, and polyvinylnitrate (PVN) at sub-nanosecond time scales are reported. RDX shows a nearly linear increase in absorption with time after shock at {approx}23 GPa. PETN is similar, but with smaller total absorption. A broad visible absorption in sapphire begins nearly immediately upon shock loading but does not build over time. PVN exhibits thin film interference in the absorption spectra along with increased absorption with time. The absorptions in RDX and PETN are suggested to originate in chemical reactions happening on picosecond time scales at these shock stresses, although further diagnostics are required to prove this interpretation.

  4. Transient Mixed Convection Validation for NGNP

    SciTech Connect

    Smith, Barton; Schultz, Richard

    2015-10-19

    The results of this project are best described by the papers and dissertations that resulted from the work. They are included in their entirety in this document. They are: (1) Jeff Harris PhD dissertation (focused mainly on forced convection); (2) Blake Lance PhD dissertation (focused mainly on mixed and transient convection). This dissertation is in multi-paper format and includes the article currently submitted and one to be submitted shortly; and, (3) JFE paper on CFD Validation Benchmark for Forced Convection.

  5. Sustained Perceptual Deficits from Transient Sensory Deprivation

    PubMed Central

    Sanes, Dan H.

    2015-01-01

    Sensory pathways display heightened plasticity during development, yet the perceptual consequences of early experience are generally assessed in adulthood. This approach does not allow one to identify transient perceptual changes that may be linked to the central plasticity observed in juvenile animals. Here, we determined whether a brief period of bilateral auditory deprivation affects sound perception in developing and adult gerbils. Animals were reared with bilateral earplugs, either from postnatal day 11 (P11) to postnatal day 23 (P23) (a manipulation previously found to disrupt gerbil cortical properties), or from P23-P35. Fifteen days after earplug removal and restoration of normal thresholds, animals were tested on their ability to detect the presence of amplitude modulation (AM), a temporal cue that supports vocal communication. Animals reared with earplugs from P11-P23 displayed elevated AM detection thresholds, compared with age-matched controls. In contrast, an identical period of earplug rearing at a later age (P23-P35) did not impair auditory perception. Although the AM thresholds of earplug-reared juveniles improved during a week of repeated testing, a subset of juveniles continued to display a perceptual deficit. Furthermore, although the perceptual deficits induced by transient earplug rearing had resolved for most animals by adulthood, a subset of adults displayed impaired performance. Control experiments indicated that earplugging did not disrupt the integrity of the auditory periphery. Together, our results suggest that P11-P23 encompasses a critical period during which sensory deprivation disrupts central mechanisms that support auditory perceptual skills. SIGNIFICANCE STATEMENT Sensory systems are particularly malleable during development. This heightened degree of plasticity is beneficial because it enables the acquisition of complex skills, such as music or language. However, this plasticity comes with a cost: nervous system development

  6. Transient infantile hyperthyrotropinaemia. Report of a case.

    PubMed Central

    Miyai, K; Amino, N; Nishi, K; Fujie, T; Nakatani, K; Nose, O; Harada, T; Yabuuchi, H; Doi, K; Yamamoto, T; Satake, R; Tsuruhara, T; Oura, T

    1979-01-01

    A case of transient hyperthyrotropinaemia was found by mass screening for neonatal hypothyroidism using the paired TSH assay method. The patient was a baby boy born at term after a normal pregnancy who grew without any abnormal signs or symptoms. For the first 7 months after birth, his serum TSH was abnormally high while his total serum T4, T3, and free T4, T3 were within normal limits, exept for slightly low free T4 level at 7 months. The raised serum TSH decreased spontaneously to within normal limits after he was 9 months old. PMID:533303

  7. Modeling of transient heat pipe operation

    NASA Technical Reports Server (NTRS)

    Colwell, G. T.; Hartley, J. G.

    1985-01-01

    The overall goal is to gain a better understanding of the transient behavior of heat pipes operating under both normal and adverse conditions. Normal operation refers to cases where the capillary structure remains fully wetted. Adverse operation occurs when drying, re-wetting, choking, noncontinuum flow, freezing, thawing etc., occur within the heat pipe. The work was redirected towards developing the capability to predict operational behavior of liquid metal heat pipes used for cooling aerodynamic structures. Of particular interest is the startup of such heat pipes from an initially frozen state such as might occur during re-entry of a space vehicle into the Earth's atmosphere or during flight of hypersonic aircraft.

  8. Optical "anti-transient" detected by MASTER

    NASA Astrophysics Data System (ADS)

    Denisenko, D.; Gorbovskoy, E.; Lipunov, V.; Balanutsa, P.; Yecheistov, V.; Tiurina, N.; Kornilov, V.; Belinski, A.; Shatskiy, N.; Chazov, V.; Kuznetsov, A.; Zimnukhov, D.; Krushinsky, V.; Zalozhnih, I.; Popov, A.; Bourdanov, A.; Punanova, A.; Ivanov, K.; Yazev, S.; Budnev, N.; Konstantinov, E.; Chuvalaev, O.; Poleshchuk, V.; Gress, O.; Parkhomenko, A.; Tlatov, A.; Dormidontov, D.; Senik, V.; Yurkov, V.; Sergienko, Y.; Varda, D.; Sinyakov, E.; Shurpakov, S.; Shumkov, V.; Podvorotny, P.; Levato, H.; Saffe, C.; Mallamaci, C.; Lopez, C.; Podest, F.

    2013-02-01

    We have started the search for the disappearing stars (optical "anti-transients", OATs) in the MASTER database. The first result is the detection of a deep (~3.5 magnitudes) fading of the bright star TYC 2505-672-1 whose variability was previously unknown. This star has the coordinates 09 53 10.00 +33 53 52.7 and magnitudes V=10.71, B=12.51 in Tycho2 catalogue and J=7.61, H=6.78, K=6.57 in 2MASS.

  9. Transient acceleration in f(T) gravity

    NASA Astrophysics Data System (ADS)

    Qi, Jing-Zhao; Yang, Rong-Jia; Zhang, Ming-Jian; Liu, Wen-Biao

    2016-02-01

    Recently an f(T) gravity based on the modification of teleparallel gravity was proposed to explain the accelerated expansion of the universe. We use observational data from type Ia supernovae, baryon acoustic oscillations, and cosmic microwave background to constrain this f(T) theory and reconstruct the effective equation of state and the deceleration parameter. We obtain the best-fit values of parameters and find an interesting result that the constrained f(T) theory allows for the accelerated Hubble expansion to be a transient effect.

  10. Resolving AGN with PanSTARRS transients

    NASA Astrophysics Data System (ADS)

    Lawrence, Andy

    2012-10-01

    With PanSTARRS we have discovered a new class of slow, blue nuclear transients which we believe to be rare examples of background AGN microlensed by stars in foreground galaxies, amplified by a factor of 10--100. The background AGN should be somewhat resolved by the foreground lens, providing a unique new diagnostic of AGN size and structure - the UV, optical, IR, BLR, and X-ray regions should have differing evolutions during the event. This proposal is a first step towards understanding the structure of the X-ray source : testing the microlensing hypothesis, characterising the SED, and establishing the first two epochs in an expected gradual decline.

  11. Future Transient Testing of Advanced Fuels

    SciTech Connect

    Jon Carmack

    2009-09-01

    The transient in-reactor fuels testing workshop was held on May 4–5, 2009 at Idaho National Laboratory. The purpose of this meeting was to provide a forum where technical experts in transient testing of nuclear fuels could meet directly with technical instrumentation experts and nuclear fuel modeling and simulation experts to discuss needed advancements in transient testing to support a basic understanding of nuclear fuel behavior under off-normal conditions. The workshop was attended by representatives from Commissariat à l'Énergie Atomique CEA, Japanese Atomic Energy Agency (JAEA), Department of Energy (DOE), AREVA, General Electric – Global Nuclear Fuels (GE-GNF), Westinghouse, Electric Power Research Institute (EPRI), universities, and several DOE national laboratories. Transient testing of fuels and materials generates information required for advanced fuels in future nuclear power plants. Future nuclear power plants will rely heavily on advanced computer modeling and simulation that describes fuel behavior under off-normal conditions. TREAT is an ideal facility for this testing because of its flexibility, proven operation and material condition. The opportunity exists to develop advanced instrumentation and data collection that can support modeling and simulation needs much better than was possible in the past. In order to take advantage of these opportunities, test programs must be carefully designed to yield basic information to support modeling before conducting integral performance tests. An early start of TREAT and operation at low power would provide significant dividends in training, development of instrumentation, and checkout of reactor systems. Early start of TREAT (2015) is needed to support the requirements of potential users of TREAT and include the testing of full length fuel irradiated in the FFTF reactor. The capabilities provided by TREAT are needed for the development of nuclear power and the following benefits will be realized by the

  12. Transient magmatic convection prolonged by solidification

    NASA Technical Reports Server (NTRS)

    Brandeis, Genevieve; Marsh, Bruce D.

    1990-01-01

    Fluid dynamic experiments have been conducted on the solidification of a paraffin layer, in order to elucidate the transient stage of convection created in cooling magma by the fact that strong changes in viscosity with crystallization lock up within an inwardly propagating crust much buoyancy that would otherwise be available to drive convection. The interior of the magma remains isothermal, and the temperature decreases uniformly until it is locked at the convective liquidus; the crystals are fine hairlike dendrites without major compositional differentiations. Measurements over time are presented of crust thickness, convective velocity, and heat transfer.

  13. Transient simulation of ram accelerator flowfields

    NASA Astrophysics Data System (ADS)

    Drabczuk, Randall P.; Rolader, G.; Dash, S.; Sinha, N.; York, B.

    1993-01-01

    This paper describes the development of an advanced computational fluid dynamic (CFD) simulation capability in support of the USAF Armament Directorate ram accelerator research initiative. The state-of-the-art CRAFT computer code has been specialized for high fidelity, transient ram accelerator simulations via inclusion of generalized dynamic gridding, solution adaptive grid clustering, and high pressure thermo-chemistry. Selected ram accelerator simulations are presented that serve to exhibit the CRAFT code capabilities and identify some of the principle research/design Issues.

  14. Transient simulation of ram accelerator flowfields

    NASA Astrophysics Data System (ADS)

    Sinha, N.; York, B. J.; Dash, S. M.; Drabczuk, R.; Rolader, G. E.

    1992-10-01

    This paper describes the development of an advanced computational fluid dynamic (CFD) simulation capability in support of the U.S. Air Force Armament Directorate's ram accelerator research initiative. The state-of-the-art CRAFT computer code has been specialized for high fidelity, transient ram accelerator simulations via inclusion of generalized dynamic gridding, solution adaptive grid clustering, high pressure thermochemistry, etc. Selected ram accelerator simulations are presented which serve to exhibit the CRAFT code's capabilities and identify some of the principal research/design issues.

  15. Pressure transient method for front tracking

    SciTech Connect

    Benson, S.M.; Bodvarsson, G.S.

    1983-08-01

    A pressure transient technique for tracking the advance of cold water fronts during water flooding and goethermal injection operations has been developed. The technique is based on the concept that the steady state pressure buildup in the reservoir region inside the front can be calculated by a fluid skin factor. By analyzing successive pressure falloff tests, the advance of the front in the reservoir can be monitored. The validity of the methods is demonstrated by application to three numerically simulated data sets, a nonisothermal step-rate injection test, a series of pressure falloffs in a multilayered reservoir, and a series of pressure falloff tests in a water flooded oil reservoir.

  16. Die Tabellen von Ulugh Beg. Die Sternkataloge des Ptolemäus, Ulugh Beg und Tycho Brahe im Vergleich

    NASA Astrophysics Data System (ADS)

    Schwan, Heiner

    2002-09-01

    Im 15. Jahrhundert schuf Ulugh Beg, der Herrscher von Samarkand (1394 - 1449), ein wichtiges Tabellenwerk. Das Kernstück dieses Werks (Zij Ulugh Beg, "Tabellen Ulugh Begs") ist ein Katalog mit 1018 Sternen, ihren Helligkeiten und Positionen. In diesem Bericht werden die Zij Ulugh Beg mit den großen Katalogen von Ptolemäus und Tycho Brahe verglichen.

  17. 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.

  18. Missbrauchspotential von Verzeichnisdienst-Metadaten in LDAP-basierten System- und Benutzerverwaltungen

    NASA Astrophysics Data System (ADS)

    Pluta, Daniel

    Metadaten stellen Zusatzinformationen über elektronisch gespeicherte Kerninformationen zur Verfügung. Sie ergänzen die eigentliche Hauptinformation um nützliche Details. In vielen Bereichen werden Metadaten gespeichert und stehen zur Auswertung zur Verfügung. Alle IT-nahen Systeme, angefangen im Konsumerbereich (z.B. digitale Kameras) bis hin zu unternehmenskritischen Applikationen führen im Hintergrund Metadaten - parallel zu den eigentlichen Hauptdaten. Metadaten im Allgemeinen sind per se als neutral, d.h. weder positiv noch negativ, zu bewerten. So wirken sich diese häufig positiv auf das Finden und Sortieren von digitalen Dokumenten aus. Negativ treten Metadaten eigentlich immer nur dann in Erscheinung, sobald diese ursprünglich zusätzlichen und nützlichen (und daher im Gegensatz zu den Hauptdaten nicht besonders beachteten bzw. geschützten) Informationen entgegen ihrer Bestimmung, zweckentfremdet werden. Auch Verzeichnisdienste verfügen über solche nützlichen Metadaten zu den jeweils in ihnen gespeicherten Inhalten. Ob, und wenn ja wie weit diese nützlichen Inhalte auch ein Risiko darstellen können wird im Rahmen dieses Artikels anhand eines konkreten Szenarios aus dem Umfeld des Systemmanagements gezeigt.

  19. Molekulare Methoden zum Nachweis, zur Quantifizierung und zum Monitoring der Mykotoxinbildung lebensmittelrelevanter Pilze

    NASA Astrophysics Data System (ADS)

    Geisen, Rolf

    Schimmelpilze kommen ubiquitär vor und spielen besonders bei pflanzlichen Lebensmitteln und Rohprodukten eine besondere Rolle als Verderbsorganismen. Es wird geschätzt, dass 20-25 % der jährlichen Produktion an pflanzlichen Produkten durch Schimmelpilze verdorben werden (Smith et al., 1994). Viele der lebensmittelrelevanten Schimmelpilze sind zudem in der Lage, Mykotoxine, toxische Sekundärmetabolite, zu bilden, was das Ausmaß des Problems deutlich macht. Die wichtigsten mykotoxinbildenden Spezies gehören zu den Fusarien (Trichothecene, Fumonisine, Zearalenon), Aspergillen (Aflatoxin, Ochratoxin, Cyclopiazonsäure) und Penicillien (Patulin, Ochratoxin). Für viele Mykotoxine, wie die Aflatoxine, Ochratoxin, Fumonisine und Trichothecene sind Grenzwerte erlassen worden, die die Verkehrsfähigkeit betroffener Produkte regeln. Die Einhaltung der Grenzwerte kann sehr genau durch offizielle chemisch-analytische Methoden, wie HPLC, GC-MS etc. kontrolliert werden. Diese analytischen Methoden sind aber für die Anwendung eines HACCP-Ansatzes zur Kontrolle der Mykotoxinbildung nur bedingt geeignet, da sie Endpunktkontrollen darstellen und nur das über eine längere Zeit gebildete Mykotoxin bestimmen. Sie sagen daher nichts über die biologischen Bedingungen zur Zeit der Bildung durch den Pilz aus.

  20. Photovoltaic-electrolyzer system transient simulation results

    SciTech Connect

    Leigh, R.W.; Metz, P.D.; Michalek, K.

    1986-05-01

    Brookhaven National Laboratory has developed a Hydrogen Technology Evaluation Center to illustrate advanced hydrogen technology. The first phase of this effort investigated the use of solar energy to produce hydrogen from water via photovoltaic-powered electrolysis. A coordinated program of system testing, computer simulation, and economic analysis has been adopted to characterize and optimize the photovoltaic-electrolyzer system. This paper presents the initial transient simulation results. Innovative features of the modeling include the use of real weather data, detailed hourly modeling of thermal characteristics of the PV array and of system control strategies, and examination of systems over a wide range of power and voltage ratings. The transient simulation system TRNSYS was used, incorporating existing, modified or new component subroutines as required. For directly coupled systems, the authors found the PV array voltage which maximizes hydrogen production to be quite near the nominal electrolyzer voltage for a wide range of PV array powers. The array voltage which maximizes excess electricity production is slightly higher. The use of an ideal (100 percent efficient) maximum power tracking system provides only a six percent increase in annual hydrogen production. An examination of the effect of the PV array tilt indicates, as expected, that annual hydrogen production is insensitive to tilt angle within +-20 deg of latitude. Summer production greatly exceeds winter generation. Tilting the array, even to 90 deg, produces no significant increase in winter hydrogen production.

  1. Automated Classification of Transient and Variable Sources

    NASA Astrophysics Data System (ADS)

    Donalek, Ciro; Graham, M.; Mahabal, A. A.; Djorgovski, S. G.; Drake, A. J.; Yang, M.; Maker, A.; Duan, V.

    2013-01-01

    Better and faster technology is increasing the amount of collected data in many scientific fields, all of them requiring a common task: extract knowledge from massive, multi parametric data sets, as rapidly and efficiently possible. Most systems today rely on a delayed human judgment and this “manual” approach will simply not scale to the next generation of surveys thus the need of a machine learning approach. We present a sleeping expert framework that makes use of many different ensembles of classifiers (eg, kNN, Neural Networks, Bayesian Networks, Decision Trees) that can be activated according to the input data; results from the single classifiers are then combined in order to achieve a better classification rate. Using data sets extracted from the ongoing Catalina Real-Time Transient Surveys (CRTS), we show the results obtained applying this framework to different astronomical problems (eg, classifying transients on the basis of features describing the light curves, systematic search of CV). Moreover, we illustrate a variety of feature selection strategies used to identify the subsets that give the most information; given the high number of parameters this is quickly becoming a crucial task in analyzing astronomical data sets.

  2. Enhancing photocurrent transient spectroscopy by electromagnetic modeling.

    PubMed

    Diesinger, H; Panahandeh-Fard, M; Wang, Z; Baillargeat, D; Soci, C

    2012-05-01

    The shape and duration of photocurrent transients generated by a photoconductive switch depend on both the intrinsic response of the active material and the geometry of the transmission line structure. The present electromagnetic model decouples both shape forming contributions. In contrast to previously published work, it accounts for the particular operating mode of transient spectroscopy. The objective is to increase the time resolution by two approaches, by optimizing structural response and by deconvolving it from experimental data. The switch structure is represented by an effective transimpedance onto which the active material acts as current generator. As proof of concept, the response of a standard microstrip switch is modeled and deconvolved from experimental data acquired in GaAs, yielding a single exponential material response and hence supporting the validity of the approach. Beyond compensating for the response deterioration by the structure, switch architectures can be a priori optimized with respect to frequency response. As an example, it is shown that a microstrip gap that can be deposited on materials incompatible with standard lithography reduces pulse broadening by an order of magnitude if it is provided with transitions to coplanar access lines.

  3. Optimal Transient Growth of Submesoscale Baroclinic Instabilities

    NASA Astrophysics Data System (ADS)

    White, Brian; Zemskova, Varvara; Passaggia, Pierre-Yves

    2016-11-01

    Submesoscale instabilities are analyzed using a transient growth approach to determine the optimal perturbation for a rotating Boussinesq fluid subject to baroclinic instabilities. We consider a base flow with uniform shear and stratification and consider the non-normal evolution over finite-time horizons of linear perturbations in an ageostrophic, non-hydrostatic regime. Stone (1966, 1971) showed that the stability of the base flow to normal modes depends on the Rossby and Richardson numbers, with instabilities ranging from geostrophic (Ro -> 0) and ageostrophic (finite Ro) baroclinic modes to symmetric (Ri < 1 , Ro > 1) and Kelvin-Helmholtz (Ri < 1 / 4) modes. Non-normal transient growth, initiated by localized optimal wave packets, represents a faster mechanism for the growth of perturbations and may provide an energetic link between large-scale flows in geostrophic balance and dissipation scales via submesoscale instabilities. Here we consider two- and three-dimensional optimal perturbations by means of direct-adjoint iterations of the linearized Boussinesq Navier-Stokes equations to determine the form of the optimal perturbation, the optimal energy gain, and the characteristics of the most unstable perturbation.

  4. Transient ponderomotive effects in superconducting cavities

    SciTech Connect

    Kirk Davis; Thomas Powers

    2005-07-10

    A number of experiments were performed on an installed and operational 5-cell CEBAF cavity to determine the minimum time required to re-establish stable gradient after a cavity window arc trip. Once it was determined that gradient could be re-established within 10 ms by applying constant power RF signal in a voltage controlled Oscillator-phase locked loop based system (VCO-PLL), a second experiment was performed to determine if stable gradient could be re-established using a fixed frequency RF system with a simple gradient based closed loop control system. During this test, fluctuations were observed in the cavity forward power signal, the source of which was later determined to be pondero-motive in nature. These ponderomotive induced vibrations were quantified using a cavity resonance monitor and a VCO-PLL RF system. Experimental results, analysis of the resultant klystron power transients, the decay time of the transients, and the implications with respect to fast reset algorithms will be presented.

  5. Direct Numerical Simulations of Transient Dispersion

    NASA Astrophysics Data System (ADS)

    Porter, M.; Valdes-Parada, F.; Wood, B.

    2008-12-01

    Transient dispersion is important in many engineering applications, including transport in porous media. A common theoretical approach involves upscaling the micro-scale mass balance equations for convection- diffusion to macro-scale equations that contain effective medium quantities. However, there are a number of assumptions implicit in the various upscaling methods. For example, results obtained from volume averaging are often dependent on a given set of length and time scale constraints. Additionally, a number of the classical models for dispersion do not fully capture the early-time dispersive behavior of the solute for a general set of initial conditions. In this work, we present direct numerical simulations of micro-scale transient mass balance equations for convection-diffusion in both capillary tubes and porous media. Special attention is paid to analysis of the influence of a new time- decaying coefficient that filters the effects of the initial conditions. The direct numerical simulations were compared to results obtained from solving the closure problem associated with volume averaging. These comparisons provide a quantitative measure of the significance of (1) the assumptions implicit in the volume averaging method and (2) the importance of the early-time dispersive behavior of the solute due to various initial conditions.

  6. Detecting Thermal Cloaks via Transient Effects

    PubMed Central

    Sklan, Sophia R.; Bai, Xue; Li, Baowen; Zhang, Xiang

    2016-01-01

    Recent research on the development of a thermal cloak has concentrated on engineering an inhomogeneous thermal conductivity and an approximate, homogeneous volumetric heat capacity. While the perfect cloak of inhomogeneous κ and inhomogeneous ρcp is known to be exact (no signals scattering and only mean values penetrating to the cloak’s interior), the sensitivity of diffusive cloaks to defects and approximations has not been analyzed. We analytically demonstrate that these approximate cloaks are detectable. Although they work as perfect cloaks in the steady-state, their transient (time-dependent) response is imperfect and a small amount of heat is scattered. This is sufficient to determine the presence of a cloak and any heat source it contains, but the material composition hidden within the cloak is not detectable in practice. To demonstrate the feasibility of this technique, we constructed a cloak with similar approximation and directly detected its presence using these transient temperature deviations outside the cloak. Due to limitations in the range of experimentally accessible volumetric specific heats, our detection scheme should allow us to find any realizable cloak, assuming a sufficiently large temperature difference. PMID:27605153

  7. Transient expression of doublecortin during adult neurogenesis.

    PubMed

    Brown, Jason P; Couillard-Després, Sébastien; Cooper-Kuhn, Christiana M; Winkler, Jürgen; Aigner, Ludwig; Kuhn, H Georg

    2003-12-01

    During development of the central nervous system, expression of the microtubule binding protein doublecortin (DCX) is associated with migration of neuroblasts. In addition to this developmental role, expression of DCX remains high within certain areas of the adult mammalian brain. These areas, mainly the dentate gyrus and the lateral ventricle wall in conjunction with the rostral migratory stream and olfactory bulb, retain the capacity to generate new neurons into adulthood. Adult neurogenesis is typically detected by incorporation of bromodeoxyuridine (BrdU) into dividing cells and colabeling of BrdU-positive cells with markers for mature neurons. To elucidate whether DCX could act as an alternative indicator for adult neurogenesis, we investigated the temporal expression pattern of DCX in neurogenic regions of the adult brain. Analysis of newly generated cells showed that DCX is transiently expressed in proliferating progenitor cells and newly generated neuroblasts. As the newly generated cells began expressing mature neuronal markers, DCX immunoreactivity decreased sharply below the level of detection and remained undetectable thereafter. The transient expression pattern of DCX in neuronal committed progenitor cells/neuroblasts indicates that DCX could be developed into a suitable marker for adult neurogenesis and may provide an alternative to BrdU labeling. This assumption is further supported by our observation that the number of DCX-expressing cells in the dentate gyrus was decreased with age according to the reduction of neurogenesis in the aging dentate gyrus previously reported.

  8. Transient QED effects in absorbing dielectrics

    NASA Astrophysics Data System (ADS)

    Wubs, Martijn; Suttorp, L. G.

    2001-04-01

    The spontaneous-emission rate of a radiating atom reaches its time-independent equilibrium value after an initial transient regime. In this paper, we consider the associated relaxation effects of the spontaneous-decay rate of atoms in dispersive and absorbing dielectric media for atomic-transition frequencies near material resonances. A quantum mechanical description of such media is furnished by a damped-polariton model in which absorption is taken into account through coupling to a bath. We show how all field and matter operators in this theory can be expressed in terms of the bath operators at an initial time. The consistency of these solutions for the field and matter operators are found to depend on the validity of certain velocity sum rules. The transient effects in the spontaneous-decay rate are studied with the help of several specific models for the dielectric constant, which are shown to follow from the general theory by adopting particular forms of the bath coupling constant.

  9. Transient phenomena in rotary kiln incineration

    SciTech Connect

    Linak, W.P.; Kilgroe, J.D.; Wendt, J.O.; Mc Sorley, J.A.; Dunn, J.E.

    1986-01-01

    This paper describes results of an ongoing experimental investigation at the U.S. Environmental Protection Agency into the waste properties and kiln parameters that determine both the instantaneous intensity and the total magnitude of transient puffs leaving the kiln. The experimental apparatus utilized was a 73 kW (250,000 Btu/hr) laboratory rotary kiln simulator. Surrogate solid wastes in the form of plastic rods and surrogate liquid wastes on corncob sorbent in cardboard containers were investigated. A statistically designed parametric study was used to determine the extent to which waste and kiln variables (such as charge mass, charge surface area, charge composition, kiln temperature, and kiln rotation speed) affected the intensity (hydrocarbon peak height) and magnitude (hydrocarbon peak area) of puffs. Results demonstrate the relative ease with which failure conditions are achieved, even at high excess air values and high kiln temperatures. Transient puffs arising from even innocuous surrogate wastes can contain a number of hazardous compounds. Increasing kiln temperature and kiln rotation speed can cause an adverse effect on puff intensity, probably due to increased devolatilization rates.

  10. Light Echoes of Transients and Variables

    NASA Astrophysics Data System (ADS)

    Rest, Armin

    2012-04-01

    abstract-type="normal">SummaryTycho Brahe's observations of a supernova in 1572 challenged the contemporaneous European view of the cosmos that the celestial realm was unchanging. 439 years later we have once again seen the light that Tycho saw, as some of the light from the 1572 supernova is reflected off dust and is only now reaching Earth. These light echoes, as well as ones detected from other transients and variables, give us a very rare opportunity in astronomy: direct observation of the cause (the supernova explosion) and the effect (the supernova remnant) of the same astronomical event. Furthermore, in some cases we can compare light echoes at different angles around a supernova remnant, and thus investigate possible asymmetry in the supernova explosion. In addition, in cases where the scattering dust is favorably positioned, the geometric distance to the SN remnant can be determined using polarization measurements. These techniques have been successfully applied to various transients in the last decade, and the talk gave an overview of the scientific results and techniques, with a particular focus on the challenges we will face in the current and upcoming wide-field time-domain surveys.

  11. Inferring sparse networks for noisy transient processes

    NASA Astrophysics Data System (ADS)

    Tran, Hoang M.; Bukkapatnam, Satish T. S.

    2016-02-01

    Inferring causal structures of real world complex networks from measured time series signals remains an open issue. The current approaches are inadequate to discern between direct versus indirect influences (i.e., the presence or absence of a directed arc connecting two nodes) in the presence of noise, sparse interactions, as well as nonlinear and transient dynamics of real world processes. We report a sparse regression (referred to as the -min) approach with theoretical bounds on the constraints on the allowable perturbation to recover the network structure that guarantees sparsity and robustness to noise. We also introduce averaging and perturbation procedures to further enhance prediction scores (i.e., reduce inference errors), and the numerical stability of -min approach. Extensive investigations have been conducted with multiple benchmark simulated genetic regulatory network and Michaelis-Menten dynamics, as well as real world data sets from DREAM5 challenge. These investigations suggest that our approach can significantly improve, oftentimes by 5 orders of magnitude over the methods reported previously for inferring the structure of dynamic networks, such as Bayesian network, network deconvolution, silencing and modular response analysis methods based on optimizing for sparsity, transients, noise and high dimensionality issues.

  12. Transient magnetic field signatures at high latitudes

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    1993-01-01

    We survey GOES 2/5/6 geosynchronous and Huancayo, Peru, ground magnetometer observations at the times of 70 transient (2-10 min) events recorded at South Pole Station, Antarctica. The simultaneous observations indicate that most South Pole events correspond to sudden sharp variations in the equatorial magnetospheric and low-latitude ground magnetic field. The exceptions occur when the South Pole events have weak amplitudes and/or Huancayo and GOES 2/5/6 are far from local noon. The corresponding features observed at GOES 5 and GOES 6 are generally similar, with a lag indicating antisunward motion. A similar antisunward motion may be inferred from the ground observations themselves. On a case-by-case and statistical basis, the characteristics of the events observed in South Pole ground magnetograms resemble those previously interpreted as sudden impulse and sudden storm commencement signatures at other high-latitude stations. These observations suggest that the transient events at South Pole form part of the magnetospheric and ionospheric response to a sudden change in the fraction of the solar wind dynamic pressure applied to the magnetosphere.

  13. Solarwind Transient flows and Associated Forbush Decrease

    NASA Astrophysics Data System (ADS)

    Kaushik, S. C.; Subhash Chandra Kaushik

    2011-12-01

    In this study we discuss the behavior of cosmic rays during the phase of highly intense or ultra intense geomagnetic storms, as shocks driven by energetic coronal mass ejections (CME's) and other interplanetary (IP) transients are mainly responsible for initiating large and intense geomagnetic storms. Observational results indicate that galactic cosmic rays (CR) coming from deep surface interact with these abnormal solar and IP conditions and suffer modulation effects. In this paper a systematic study has been performed to analyze the CRI variation during super storms i.e. very intense geomagnetic storms with Dst index ≥ -100 nT. The neutron monitor data of three stations Oulu (Rc = 0.77 GV), Climax (Rc = 2.97 GV) and Huancayo (Rc = 13.01 GV) well distributed over different latitudes and hourly values of IMF parameters derived from satellite observations near Earth IP medium from OMNI Data base is used for the period spanning over solar cycles 20, 21, 22 and 23. It is found that AP and AE indices show rise before the forward turnings of IMF, while the Dst index shows a classic storm time decrease. The analysis indicates that the magnitude of all the responses depends on BZ component of IMF being well correlated with solar maximum and minimum periods. Transient decrease in CRI with slow recovery is observed during the storm phase duration.

  14. Transient magnetic field signatures at high latitudes

    SciTech Connect

    Sibeck, D.G. )

    1993-01-01

    We survey GOES 2/5/6 geosynchronous and Huancayo, Peru, ground magnetometer observations at the times of 70 transient (2-10 min) events recorded at South Pole Station, Antarctica. The simultaneous observations indicate that most South Pole events correspond to sudden sharp variations in the equatorial magnetospheric and low-latitude ground magnetic field. The exceptions occur when the South Pole events have weak amplitudes and/or Huancayo and GOES 2/5/6 are far from local noon. The corresponding features observed at GOES 5 and GOES 6 are generally similar, with a lag indicating antisunward motion. A similar antisunward motion may be inferred from the ground observations themselves. On a case-by-case and statistical basis, the characteristics of the events observed in South Pole ground magnetograms resemble those previously interpreted as sudden impulse and sudden storm commencement signatures at other high-latitude stations. These observations suggest that the transient events at South Pole form part of the magnetospheric and ionospheric response to a sudden change in the fraction of the solar wind dynamic pressure applied to the magnetosphere. 57 refs., 14 figs.

  15. Nonlinear transient analysis of joint dominated structures

    NASA Technical Reports Server (NTRS)

    Chapman, J. M.; Shaw, F. H.; Russell, W. C.

    1987-01-01

    A residual force technique is presented that can perform the transient analyses of large, flexible, and joint dominated structures. The technique permits substantial size reduction in the number of degrees of freedom describing the nonlinear structural models and can account for such nonlinear joint phenomena as free-play and hysteresis. In general, joints can have arbitrary force-state map representations but these are used in the form of residual force maps. One essential feature of the technique is to replace the arbitrary force-state maps describing the nonlinear joints with residual force maps describing the truss links. The main advantage of this replacement is that the incrementally small relative displacements and velocities across a joint are not monitored directly thereby avoiding numerical difficulties. Instead, very small and 'soft' residual forces are defined giving a numerically attractive form for the equations of motion and thereby permitting numerically stable integration algorithms. The technique was successfully applied to the transient analyses of a large 58 bay, 60 meter truss having nonlinear joints. A method to perform link testing is also presented.

  16. GTRAN- TRANSIENT ANALYSIS OF GAS PIPING SYSTEMS

    NASA Technical Reports Server (NTRS)

    TROVILLION T A

    1994-01-01

    The GTRAN program was developed to solve transient, as well as steady state, problems for gas piping systems. GTRAN capabilities allow for the analysis of a variety of system configurations and components. These include: multiple pipe junctions; valves that change position with time; fixed restrictions (orifices, manual valves, filters, etc.); relief valves; constant pressure sources; and heat transfer for insulated piping and piping subjected to free or forced convection. In addition, boundary conditions can be incorporated to simulate specific components. The governing equations of GTRAN are the one-dimensional transient gas dynamic equations. The three equations for pressure, velocity, and density are reduced to numerical equations using an implicit Crank-Nicholson finite difference technique. Input to GTRAN includes a description of the piping network, the initial conditions, and any events (e.g. valve closings) occuring during the period of analysis. Output includes pressure, velocity, and density versus time. GTRAN is written in FORTRAN 77 for batch execution and has been implemented on a DEC VAX series computer. GTRAN was developed in 1983.

  17. Current transients in single nanoparticle collision events.

    PubMed

    Xiao, Xiaoyin; Fan, Fu-Ren F; Zhou, Jiping; Bard, Allen J

    2008-12-10

    Electrochemical hydrazine oxidation and proton reduction occur at a significantly higher rate at Pt than at Au or C electrodes. Thus, the collision and adhesion of a Pt particle on a less active Au or C electrode leads to a large current amplification by electrocatalysis at single nanoparticles (NPs). At low particle concentrations, the collision of Pt NPs was characterized by current transients composed of individual current profiles that rapidly attained a steady state, signaling single NP collisions. The characteristic steady-state current was used to estimate the particle size. The fluctuation in collision frequency with time indicates that the collision of NPs at the detector electrodes occurs in a statistically random manner, with the average frequency a function of particle concentration and diffusion coefficient. A longer term current decay in single current transients, as opposed to the expected steady-state behavior, was more pronounced for proton reduction than for hydrazine oxidation, revealing microscopic details of the nature of the particle interaction with the detector electrode and the kinetics of electrocatalysis at single NPs. The study of single NP collisions allows one to screen particle size distributions and estimate NP concentrations and diffusion coefficients.

  18. CUTIE: Cubesat Ultraviolet Transient Imaging Experiment

    NASA Astrophysics Data System (ADS)

    Cenko, Stephen B.; Bellm, Eric Christopher; Gal-Yam, Avishay; Gezari, Suvi; Gorjian, Varoujan; Jewell, April; Kruk, Jeffrey W.; Kulkarni, Shrinivas R.; Mushotzky, Richard; Nikzad, Shouleh; Piro, Anthony; Waxman, Eli; Ofek, Eran Oded

    2017-01-01

    We describe a mission concept for the Cubesat Ultraviolet Transient Imaging Experiment (CUTIE). CUTIE will image an area on the sky of ~ 1700 square degrees every ~ 95 min at near-UV wavelengths (260-320 nm) to a depth of 19.0 mag (AB). These capabilities represent orders of magnitude improvement over past UV imagers, allowing CUTIE to conduct the first true synoptic survey of the transient and variable sky in the UV bandpass. CUTIE will uniquely address key Decadal Survey science questions such as how massive stars end their lives, how super-massive black holes accrete material and influence their surroundings, and how suitable habitable-zone planets around low-mass stars are for hosting life. By partnering with upcoming ground-based time-domain surveys, CUTIE will further leverage its low-Earth orbit to provide a multi-wavelength view of the dynamic universe that can only be achieved from space. The remarkable sensitivity for such a small payload is achieved via the use of large format delta-doped CCDs; space qualifying this technology will serve as a key milestone towards the development of future large missions (Explorers and Surveyors). Finally, our innovative design in a 6U cubesat form factor will enable significant cost savings, accelerating the timeline from conception to on-sky operation (5 years; well matched for graduate student participation).

  19. Thermonuclear model for high energy transients

    SciTech Connect

    Woosley, S.E.

    1982-01-01

    The thermonuclear model for x- and ..gamma..-ray bursts is discussed. Different regimes of nuclear burning are reviewed, each appropriate to a given range of (steady state) accretion rate. Accretion rates in the range 10/sup -14/ to 10/sup -8/ Msub solar y/sup -1/ all appear capable of producing x-ray transients of various durations and intervals. Modifications introduced by radiatively driven mass loss, the thermal inertia of the envelope, different burning mechanisms, and two-dimensional considerations are discussed as are difficulties encountered when the thermonuclear model is confronted with observations of rapidly recurrent bursts (less than or equal to 10 min), and super-Eddington luminosities and temperatures. Results from a numerical simulation of a combined hydrogen-helium runaway initiated at pycnonuclear density are presented for the first time. The thermonuclear model for ..gamma..-ray bursts is also reviewed and updated, particularly with regard to the breakdown of the steady state hypothesis employed in previous work. Solely on the basis of nuclear instability, ..gamma..-ray bursts of various types appear possible for a very broad variety of accretion rates (approx. 10/sup -17/ to approx. 10/sup -11/ Msub solar y/sup -1/) although other considerations may restrict this range. The thermonuclear model appears capable of yielding a great diversity of high energy transient phenomena for various accretion rates, magnetic field configurations, and neutron star envelope histories.

  20. Transient inter-cellular polymeric linker.

    PubMed

    Ong, Siew-Min; He, Lijuan; Thuy Linh, Nguyen Thi; Tee, Yee-Han; Arooz, Talha; Tang, Guping; Tan, Choon-Hong; Yu, Hanry

    2007-09-01

    Three-dimensional (3D) tissue-engineered constructs with bio-mimicry cell-cell and cell-matrix interactions are useful in regenerative medicine. In cell-dense and matrix-poor tissues of the internal organs, cells support one another via cell-cell interactions, supplemented by small amount of the extra-cellular matrices (ECM) secreted by the cells. Here we connect HepG2 cells directly but transiently with inter-cellular polymeric linker to facilitate cell-cell interaction and aggregation. The linker consists of a non-toxic low molecular-weight polyethyleneimine (PEI) backbone conjugated with multiple hydrazide groups that can aggregate cells within 30 min by reacting with the aldehyde handles on the chemically modified cell-surface glycoproteins. The cells in the cellular aggregates proliferated; and maintained the cortical actin distribution of the 3D cell morphology while non-aggregated cells died over 7 days of suspension culture. The aggregates lost distinguishable cell-cell boundaries within 3 days; and the ECM fibers became visible around cells from day 3 onwards while the inter-cellular polymeric linker disappeared from the cell surfaces over time. The transient inter-cellular polymeric linker can be useful for forming 3D cellular and tissue constructs without bulk biomaterials or extensive network of engineered ECM for various applications.

  1. Neutronics and Transient Calculations for the Conversion of the Transient Reactor Rest Facility (TREAT)

    SciTech Connect

    Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Papadias, Dionissios D.; Wright, Arthur E.

    2015-01-01

    The Transient Reactor Test Facility (TREAT) is a graphite-reflected, graphitemoderated, and air-cooled reactor fueled with 93.1% enriched UO2 particles dispersed in graphite, with a carbon-to-235U ratio of ~10000:1. TREAT was used to simulate accident conditions by subjecting fuel test samples placed at the center of the core to high energy transient pulses. The transient pulse production is based on the core’s selflimiting nature due to the negative reactivity feedback provided by the fuel graphite as the core temperature rises. The analysis of the conversion of TREAT to low enriched uranium (LEU) is currently underway. This paper presents the analytical methods used to calculate the transient performance of TREAT in terms of power pulse production and resulting peak core temperatures. The validation of the HEU neutronics TREAT model, the calculation of the temperature distribution and the temperature reactivity feedback as well as the number of fissions generated inside fuel test samples are discussed.

  2. The Palomar Transient Factory View of the Transient and Variable Sky

    NASA Astrophysics Data System (ADS)

    Prince, Thomas A.; PTF Collaboration

    2013-01-01

    The Palomar Transient Factory (PTF) is an automated wide-field optical survey designed to detect and characterize transient and variable sources. PTF has been in operation since early 2009, and has covered more than 20,000 square degrees in multiple epochs. It has detected and spectroscopically confirmed over 2000 supernovae and over 200 cataclysmic variables (CVs). Variable objects detected by PTF include several new compact AM CVn binaries, a redback milisecond pulsar system, as well as intermediate polar (IP) systems. The survey consists of a 7 sq deg CCD imager mounted on the Palomar Samuel Oschin Schmidt 48" telescope, a dedicated photometric follow-up telescope, and two data pipelines: an image-subtraction pipeline for prompt detection of transients, and a photometric/astrometric pipeline for point source identification and light-curve generation. PTF achieves a single epoch limiting magnitude in R-band of about 20.5 and an astrometric precision of about 0.1'' FWHM. Co-added images typically reach an R-band magnitude of 22 or fainter. This talk will describe the PTF survey with particular emphasis on PTF detections and observations of high-energy transients and other sources for which relativistic astrophysics plays an important role.

  3. Transient analysis of the 1991 Hijiori Shallow Reservoir Circulation Test

    SciTech Connect

    Hyodo, M.; Shinohara, N.; Takasugi, S.; Wright, C.A.; Conant, R..

    1996-01-24

    Like any dynamic system, HDR reservoirs cannot be fully characterized by their steady-state behavior. Circulation tests analysis should be performed on both the steady-state response and the transient response of HDR systems. Transient analysis allows not only estimation of critical reservoir parameters and how these parameters change with operating conditions / history, but transient analysis also aids in evaluating the feasibility of various modes of HDR system operation (base load, load following, etc.). This paper details the transient analysis of NEDO's FY 1991 Shallow Reservoir Circulation Test at the Hijiori HDR site in Japan. Reservoir fluid storage is carefully bounded through the employment of two distinct methods for calculation of the fluid storage from the observed transient response. A brief discussion is also included of the distribution of reservoir fluid storage; the relationship between pressure, reservoir stress, and apparent reservoir capacitance; and appropriate circulation test design to facilitate transient analysis.

  4. Planeten beobachten. Praktische Anleitung für Amateurbeobachter und solche, die es werden wollen.

    NASA Astrophysics Data System (ADS)

    Roth, G. D.

    Contents: 1. Amateurastronomie und Planetenbeobachtung (H.-J. Mettig, G. D. Roth). 2. Die visuelle Beobachtung (G. D. Roth). 3. Mond- und Planetenphotographie (B. Koch). 4. Die CCD-Bildbearbeitung (R. A. Hillebrecht). 5. Tabellen zur Ermittlung der Belichtungszeiten für Mond- und Planetenaufnahmen (W. Gruschel). 6. Die lichtelektrische Beobachtung (G. D. Roth). 7. Die Objekte in Einzeldarstellungen: Merkur (D. Niechoy); Venus (D. Niechoy); Erdmond (G. D. Roth); Mars (C. M. Schambeck); Kleine Planeten (M. Hoffmann, G. D. Roth, J. Meeus); Jupiter (H.-J. Mettig, R. C. Stoyan, A. Nikolai, C. Kowalec, G. Hahn); Saturn (R. C. Stoyan, G. Hahn, H.-J. Mettig); Uranus (R. C. Stoyan); Neptun (R. C. Stoyan); Pluto (R. C. Stoyan). 8. Adressen, Literaturhinweise, Register.

  5. Highlights of Transient Plume Impingement Model Validation and Applications

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2011-01-01

    This paper describes highlights of an ongoing validation effort conducted to assess the viability of applying a set of analytic point source transient free molecule equations to model behavior ranging from molecular effusion to rocket plumes. The validation effort includes encouraging comparisons to both steady and transient studies involving experimental data and direct simulation Monte Carlo results. Finally, this model is applied to describe features of two exotic transient scenarios involving NASA Goddard Space Flight Center satellite programs.

  6. Coronal transient--eruptive prominence of 1980 August 5

    SciTech Connect

    Fisher, R.; Garcia, C.J.; Seagraves, P.

    1981-06-15

    A coronal transient was observed in association with an eruptive prominence event using the Mauna Loa experiment system. The transient, a rarefaction, formed before the acceleration of the eruptive prominence. Upward velocities of various features, as seen in the plane of the sky, show a marked difference as a function of time between the transient and the eruptive prominence. A region of enhanced electron density formed slowly in front of the rarefaction.

  7. Laser-induced transient grating setup with continuously tunable period

    SciTech Connect

    Vega-Flick, A.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Khanolkar, A.; Abi Ghanem, M.; Boechler, N.; Alvarado-Gil, J. J.

    2015-12-15

    We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

  8. Searching for Low-Frequency Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Tsai-Wei, Jr.; Cutchin, Sean; Kothari, Manthan; Schmitt, Christian; Kavic, Michael; Simonetti, John

    2011-10-01

    Supernovae events may be accompanied by prompt emission of a low-frequency electromagnetic transient. These transient events are created by the interaction of a shock wave of charged particles created by SN core-collapse with a stars ambient magnetic field. Such events can be detected in low-frequency radio array. Here we discuss an ongoing search for such events using two radio arrays: the Long Wavelength Array (LWA) and Eight-meter-wavelength Transient Array (ETA).

  9. Classification of Transient Phenomena in Distribution System using wavelet Transform

    NASA Astrophysics Data System (ADS)

    Sedighi, Alireza

    2014-05-01

    An efficient procedure for classification of transient phenomena in distribution systems is proposed in this paper. The proposed method has been applied to classify some transient phenomena such as inrush current, load switching, capacitor switching and single phase to ground fault. The new scheme is based on wavelet transform algorithm. All of the events for feature extraction and test are simulated using Electro Magnetic Transient Program (EMTP). Results show high accuracy of proposed method.

  10. Active Region Transient Brightenings : EIT Versus SXT

    NASA Astrophysics Data System (ADS)

    Berghmans, D.; McKenzie, D.; Clette, F.

    1999-10-01

    On May 13, 1998, the Extreme-Ultraviolet Imaging Telescope (EIT, on board SOHO) has produced a unique image sequence operating in 'shutterless mode' (SOHO JOP 80). In JOP 80, EIT is the leading instrument, followed by several space born instruments (SXT, TRACE, MDI, CDS, SUMER), as well as two observatories on the ground (in La Palma and Sac Peak). The target of the campaign was a relatively small but rapidly evolving active region (AR 8218). For the EIT contribution, a 15 s cadence was achieved in the Fe XII bandpass at 195 deg by leaving EIT's shutter open for 1 hour and operating the CCD in frame transfer mode. We have started the analysis of the huge data set, by making an inventory of the transients observed in the EIT image sequence. These transients range from a B3.5 flare producing a large plasma flow along pre-existing loops, to smaller EUV brightenings of active region loops. In addition, a new class of weaker footpoint brightenings was discovered that produce wave-like disturbances propagating along quasi-open field lines (see the presentation by Eva Robbrecht at this workshop). In this paper we take the opportunity provided by JOP 80, to investigate the correspondence of the transient brightenings observed by EIT in this active region, with the ARTB previously observed by SXT and studied by Shimizu (1992). Within the simultaneous high cadence SOHO JOP 80 image sequences, both EIT and SXT accummulated a few tens of brightening events. At the time of the writing of this abstract, we can say that most of the SXT events have indeed 1 or more EIT counterparts. Typically the SXT events are somewhat bigger than the EIT events where the latter are ussualy located toward the point of origin of the SXT events. Whereas a few brightenings exist in one dataset without any trace in the other dataset (in both directions), we have additionally for a few brightenings in the SXT data, a corresponding EIT darkening as if the plasma is suddenly heated and dissappears from

  11. Technische Systeme für den Herzersatz und die Herzunterstützung

    NASA Astrophysics Data System (ADS)

    Schöb, Reto; Loree, Howard M.

    Herzkrankheiten verursachen allein in den Vereinigten Staaten jährlich mehr als 700’000 Todesfälle. Ungefähr 3 Millionen Patienten in den U.S.A. leiden gemäss der American Heart Association (AHA) und dem National Heart, Lung and Blood Institute (NHLBI) an kongestivem Herzversagen (Congestive Heart Failure, CHF), welches eine chronische, sehr entkräftende und degenerative Krankheit ist: Das Herz ist dabei unfähig, hinreichend Blut zu den Organen des Körpers zu pumpen. Über 400’000 Fälle von CHF werden jedes Jahr diagnostiziert. Ähnliche Zahlen werden für Europa und Japan zusammen geschätzt. Basierend auf Daten vom AHA und NHLBI beträgt die fünfjährige Überlebensrate für CHF-Patienten lediglich etwa 50% [1]. 70’000-120’000 dieser Patienten könnten von einer Herzverpflanzung profitieren. 1999 wurden in den USA aber nur 2185 Herztransplantationen durchgeführt während die Warteliste über 4000 Patienten beträgt [2]. Ein akuter Mangel an Spenderherzen und die enormen Kosten (250’000-400’000 USD pro Patient) sind die begrenzenden Faktoren für Herztransplantationen [3]. Dies bedeutet, dass eine riesige Anzahl von Patienten durch ein zuverlässiges und verschleissfreies, nichtthrombotisches, total implantierbares, künstliches Herz gerettet werden könnten. Bis heute jedoch kein derartiges Implantat kommerziell verfügbar.

  12. Transients in the synchronization of asymmetrically coupled oscillator arrays

    NASA Astrophysics Data System (ADS)

    Cantos, C. E.; Hammond, D. K.; Veerman, J. J. P.

    2016-09-01

    We consider the transient behavior of a large linear array of coupled linear damped harmonic oscillators following perturbation of a single element. Our work is motivated by modeling the behavior of flocks of autonomous vehicles. We first state a number of conjectures that allow us to derive an explicit characterization of the transients, within a certain parameter regime Ω. As corollaries we show that minimizing the transients requires considering non-symmetric coupling, and that within Ω the computed linear growth in N of the transients is independent of (reasonable) boundary conditions.

  13. Computer analysis of transient voltages in large grounding systems

    SciTech Connect

    Grcev, L.D.

    1996-04-01

    A computer model for transient analysis of a network of buried and above ground conductors is presented. The model is based on the electromagnetic field theory approach ad the modified image theory. Validation of the model is achieved by comparison with field measurements. The model is applied for computation of transient voltages to remote ground of large grounding grid conductors. Also computation of longitudinal and leakage currents, transient impedance, electromagnetic fields, and transient induced voltages is possible. This model is aimed to help in EMC and lightning protection studies that involve electrical and electronic systems connected to grounding systems.

  14. Radioactive powered transients from compact object mergers

    NASA Astrophysics Data System (ADS)

    Roberts, Luke

    2017-01-01

    The origin of the r-process elements remains the biggest unsolved question in our understanding of chemical evolution in the Milky Way. The most likely astrophysical sites for the formation of these nuclei involve dynamical events in the lives of neutron stars: the merger of a neutron star and another compact object. In these environments, nuclear physics plays a paramount role in determining both the evolution of the dense object itself and what nuclei are synthesized in material that is ejected from the system. When the radioactive nuclei produced in these events decay, they can heat material that is unbound during the merger and power optical or infrared transients. In this talk, I will discuss nucleosynthesis and matter ejection in neutron star mergers, with an eye toward electromagnetic observables associated with these events that may give us a direct window into the formation of the r-process elements.

  15. Monitoring transients in low inductance circuits

    DOEpatents

    Guilford, Richard P.; Rosborough, John R.

    1987-01-01

    A pair of flat cable transmission lines are monitored for transient current spikes by using a probe connected to a current transformer by a pickup loop and monitoring the output of the current transformer. The approach utilizes a U-shaped pickup probe wherein the pair of flat cable transmission lines are received between the legs of the U-shaped probe. The U-shaped probe is preferably formed of a flat coil conductor adhered to one side of a flexible substrate. On the other side of the flexible substrate there is a copper foil shield. The copper foil shield is connected to one end of the flat conductor coil and connected to one leg of the pickup loop which passes through the current transformer. The other end of the flat conductor coil is connected to the other leg of the pickup loop.

  16. A magnetohydrodynamic theory of coronal loop transients

    NASA Technical Reports Server (NTRS)

    Yeh, T.

    1982-01-01

    The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

  17. Transient Analysis of a Magnetic Heat Pump

    NASA Technical Reports Server (NTRS)

    Schroeder, E. A.

    1985-01-01

    An experimental heat pump that uses a rare earth element as the refrigerant is modeled using NASTRAN. The refrigerant is a ferromagnetic metal whose temperature rises when a magnetic field is applied and falls when the magnetic field is removed. The heat pump is used as a refrigerator to remove heat from a reservoir and discharge it through a heat exchanger. In the NASTRAN model the components modeled are represented by one-dimensional ROD elements. Heat flow in the solids and fluid are analyzed. The problem is mildly nonlinear since the heat capacity of the refrigerant is temperature-dependent. One simulation run consists of a series of transient analyses, each representing one stroke of the heat pump. An auxiliary program was written that uses the results of one NASTRAN analysis to generate data for the next NASTRAN analysis.

  18. Direct integration of transient rotor dynamics

    NASA Technical Reports Server (NTRS)

    Kascak, A. F.

    1980-01-01

    An implicit method was developed for integrating the equations of motion for a lumped mass model of a rotor dynamics system. As an aside, a closed form solution to the short bearing theory was also developed for a damper with arbitrary motion. The major conclusions are that the method is numerically stable and that the computation time is proportional to the number of elements in the rotor dynamics model rather than to the cube of the number. This computer code allowed the simulation of a complex rotor bearing system experiencing nonlinear transient motion and displayed the vast amount of results in an easily understood motion picture format - a 10 minute, 16 millimeter, color, sound motion picture supplement. An example problem with 19 mass elements in the rotor dynamics model took 0.7 second of central processing unit time per time step on an IBM 360-67 computer in a time sharing mode.

  19. Electron Acceleration by Transient Ion Foreshock Phenomena

    NASA Astrophysics Data System (ADS)

    Wilson, L. B., III; Turner, D. L.

    2015-12-01

    Particle acceleration is a topic of considerable interest in space, laboratory, and astrophysical plasmas as it is a fundamental physical process to all areas of physics. Recent THEMIS [e.g., Turner et al., 2014] and Wind [e.g., Wilson et al., 2013] observations have found evidence for strong particle acceleration at macro- and meso-scale structures and/or pulsations called transient ion foreshock phenomena (TIFP). Ion acceleration has been extensively studied, but electron acceleration has received less attention. Electron acceleration can arise from fundamentally different processes than those affecting ions due to differences in their gyroradii. Electron acceleration is ubiquitous, occurring in the solar corona (e.g., solar flares), magnetic reconnection, at shocks, astrophysical plasmas, etc. We present new results analyzing the dependencies of electron acceleration on the properties of TIFP observed by the THEMIS spacecraft.

  20. TRUMP. Transient & S-State Temperature Distribution

    SciTech Connect

    Elrod, D.C.; Turner, W.D.

    1992-03-03

    TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady-state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complex shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position, and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time-steps or on the computer time, and attainment of steady state.

  1. Transient growth of damped baroclinic waves

    NASA Technical Reports Server (NTRS)

    Farrell, B.

    1985-01-01

    A solution of the linear initial value problem for the model of Eady with the inclusion of Ekman damping is presented. This model exhibits large transient growth of perturbations for synoptic cyclone spatial scales and a realistic value of the vertical turbulent viscosity coefficient despite the fact that all normal modes are exponentially decaying. Similar results are found for the model of Charney, implying that exponential instability cannot, in general, serve to explain the occurrence of cyclone scale disturbances in midlatiudes. Rather these are seen to arise additionally and perhaps predominantly from the release of mean flow potential energy by favorably configured initial perturbations. The Petterssen criterion for midlatitude cyclogenesis results naturally from this development as does its extension to the formation of subtropical monsoon depressions. Implications for the maintenance of midlatitude temperature gradients are discussed.

  2. Transient engine performance with water ingestion

    NASA Technical Reports Server (NTRS)

    Haykin, T.; Murthy, S. N. B.

    1986-01-01

    The immediate effects on the transient performance of a generic, high bypass ratio jet engine on account of water ingestion are discussed. The air compression subsystem has been analyzed with respect to four aerothermodynamic and mechanical processes associated with two-phase fluid flow and the engine simulation has been carried out under three limiting cases of interest in practice, one pertaining to draining of water at the end of compression and the other two, to partial evaporation at two different locations in the burner. General observations are made on engine operability as a function of engine and control design under various engine and (control input) sensor operating conditions, with various mass fractions of water in the air-water mixture entering the engine, during various pilot-initiated power demand changes.

  3. Development of a transient internal probe diagnostic

    NASA Astrophysics Data System (ADS)

    Jarboe, Thomas R.; Mattick, Arthur T.

    1994-12-01

    A research effort was carried out to develop and test key components of the transient internal probe, a diagnostic tool for measuring internal magnetic fields in a plasma. A gasdynamic sabot separation method was developed for discarding the sabot upstream of the plasma. Separation is effected in a vented 50-caliber gun barrel, and the sabot is deflected upstream of the plasma, reliably removing the sabot without disrupting the probe trajectory. A vacuum interface was constructed to isolate the plasma from gun gases, which uses a very fast trap-door valve to prevent gas from entering the plasma chamber. A full-up test of the diagnostic was made using a 2.2 km/sec probe to measure a static field in a vacuum. This yielded excellent agreement with Hall probe measurements, with a resolution of 20 Gauss, and the gun gas entering the measurement chamber is to be acceptably small for application to plasma devices.

  4. Transient leukoencephalopathy after intrathecal methotrexate mimicking stroke.

    PubMed

    Agarwal, Amit; Vijay, Kanupriya; Thamburaj, Krishnamoorthy; Ouyang, Tao

    2011-08-01

    Methotrexate (MTX) is an indispensable antimetabolite for the treatment of oncological and immunological disorders in all age groups. It can be administrated intravenously as well as intrathecally and may be used alone or in combination with other drugs. Chronic leukoencephalopathy is a well-known side effect of MTX, especially in conjunction with intrathecal administration. However, acute neurotoxicity with confusion, disorientation, seizures, and focal deficits may also be seen. This can clinically mimic stroke with restricted diffusion on MRI. However, unlike stroke, there is resolution of clinical and imaging findings within 1-4 weeks. We report two cases of transient leukoencephalopathy following intrathecal methotrexate, with complete clinical and radiological resolutions on follow-up.

  5. Transient response of a laminated composite plate

    NASA Technical Reports Server (NTRS)

    Datta, S. K.; Ju, T. H.; Bratton, R. L.; Shah, A. H.

    1992-01-01

    Results are presented from an investigation of the effect of layering on transient wave propagation in a laminated cross-ply plate, giving attention to the case of 2D plane strain in the case where a line vertical force is applied on a free surface of the plate; the line may be either parallel or perpendicular to the fibers in a ply. The results are in both the time and frequency domains for the normal stress component in the x direction, at a point on the surface of the plate on which the force is applied. Comparative results are also presented for a homogeneous plate whose properties are the static effective ones, when the number of plies is large.

  6. Brane assisted quintessential inflation with transient acceleration

    SciTech Connect

    Bento, M. C.; Santos, N. M. C.; Gonzalez Felipe, R.

    2008-06-15

    A simple model of quintessential inflation with the modified exponential potential e{sup -{alpha}}{sup {phi}}[A+({phi}-{phi}{sub 0}){sup 2}] is analyzed in the braneworld context. Considering reheating via instant preheating, it is shown that the evolution of the scalar field {phi} from inflation to the present epoch is consistent with the observational constraints in a wide region of the parameter space. The model exhibits transient acceleration at late times for 0.96 < or approx. A{alpha}{sup 2} < or approx. 1.26 and 271 < or approx. {phi}{sub 0}{alpha} < or approx. 273, while permanent acceleration is obtained for 2.3x10{sup -8} < or approx. A{alpha}{sup 2} < or approx. 0.98 and 255 < or approx. {phi}{sub 0}{alpha} < or approx. 273. The steep parameter {alpha} is constrained to be in the range 5.3 < or approx. {alpha} < or approx. 10.8.

  7. Modeling of transient heat pipe operation

    NASA Technical Reports Server (NTRS)

    Colwell, Gene T.

    1987-01-01

    The use of heat pipes is being considered as a means of reducing the peak temperature and large thermal gradients at the leading edges of reentry vehicles and hypersonic aircraft and in nuclear reactors. In the basic cooling concept, the heat pipe covers the leading edge, a portion of the lower wing surface, and a portion of the upper wing surface. Aerodynamic heat is mainly absorbed at the leading edge and transported through the heat pipe to the upper and lower wing surface, where it is rejected by thermal radiation and convection. Basic governing equations are written to determine the startup, transient, and steady state performance of a haet pipe which has initially frozen alkali-metal as the working fluid.

  8. Ignition transient analysis of solid rocket motor

    NASA Technical Reports Server (NTRS)

    Han, Samuel S.

    1990-01-01

    To predict pressure-time and thrust-time behavior of solid rocket motors, a one-dimensional numerical model is developed. The ignition phase of solid rocket motors (time less than 0.4 sec) depends critically on complex interactions among many elements, such as rocket geometry, heat and mass transfer, flow development, and chemical reactions. The present model solves the mass, momentum, and energy equations governing the transfer processes in the rocket chamber as well as the attached converging-diverging nozzle. A qualitative agreement with the SRM test data in terms of head-end pressure gradient and the total thrust build-up is obtained. Numerical results show that the burning rate in the star-segmented head-end section and the erosive burning are two important parameters in the ignition transient of the solid rocket motor (SRM).

  9. Transient absorption of vibrationally excited ice Ih

    NASA Astrophysics Data System (ADS)

    Dokter, Adriaan M.; Bakker, Huib J.

    2008-01-01

    The ultrafast dynamics of HDO :D2O ice Ih at 180K is studied by midinfrared ultrafast pump-probe spectroscopy. The vibrational relaxation of HDO :D2O ice is observed to proceed via an intermediate state, which has a blueshifted absorption spectrum. Polarization resolved measurements reveal that the intermediate state is part of the intramolecular relaxation pathway of the HDO molecule. In addition, slow dynamics on a time scale of the order of 10-100ps is observed, related to thermally induced collective reorganizations of the ice lattice. The transient absorption line shape is analyzed within a Lippincott-Schroeder model for the OH-stretch potential. This analysis identifies the main mechanism behind the strong spectral broadening of the vOH=1→2 transition.

  10. Cosmological perturbations in transient phantom inflation scenarios

    NASA Astrophysics Data System (ADS)

    Richarte, Martín G.; Kremer, Gilberto M.

    2017-01-01

    We present a model of inflation where the inflaton is accommodated as a phantom field which exhibits an initial transient pole behavior and then decays into a quintessence field which is responsible for a radiation era. We must stress that the present unified model only deals with a single field and that the transition between the two eras is achieved in a smooth way, so the model does not suffer from the eternal inflation issue. We explore the conditions for the crossing of the phantom divide line within the inflationary era along with the structural stability of several critical points. We study the behavior of the phantom field within the slow-climb approximation along with the necessary conditions to have sufficient inflation. We also examine the model at the level of classical perturbations within the Newtonian gauge and determine the behavior of the gravitational potential, contrast density and perturbed field near the inflation stage and the subsequent radiation era.

  11. Cavity Enhanced Ultrafast Transient Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Allison, Thomas K.; Reber, Melanie Roberts; Chen, Yuning

    2015-06-01

    Ultrafast spectroscopy on gas phase systems is typically restricted to techniques involving photoionization, whereas solution phase experiments utilize the detection of light. At Stony Brook, we are developing new techniques for performing femtosecond time-resolved spectroscopy using frequency combs and high-finesse optical resonators. A large detection sensitivity enhancement over traditional methods enables the extension of all-optical ultrafast spectroscopies, such as broad-band transient absorption spectroscopy (TAS) and 2D spectroscopy, to dilute gas phase samples produced in molecular beams. Here, gas phase data can be directly compared to solution phase data. Initial demonstration experiments are focusing on the photodissociation of iodine in small neutral argon clusters, where cluster size strongly influences the effects solvent-caging and geminate recombination. I will discuss these initial results, our high power home-built Yb:fiber laser systems, and also extensions of the methods to the mid-IR to study the vibrational dynamics of hydrogen bonded clusters.

  12. Spontaneous transient ultrafast coherent raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Meiselman, Seth

    I explore the application of Transient Coherent Ultrafast Phonon Spectroscopy (TCUPS) to the measurement of vibrational coherence dynamics of liquid alcohols. The demonstrated technique is complementary to and, in some cases, simpler than traditional stimulated spectroscopy techniques in that it does not require more than one laser and is free of non-resonant background. I demonstrate coherence measurements of single-photon-level collective excitations: a single vibrational state at 1033 (1/cm) in; a pair of simultaneous excited vibrational states at 2834 and 2944 (1/cm) in methanol; and three simultaneous excited states at 2885, ˜2930, and 2976 (1/cm) in isopropanol. I develop a Fourier-transform-based analysis of the TCUPS data that overcomes poor signal-to-noise ratio and signal degradation due to etaloning and fluorescence. The coherence lifetimes and oscillation frequencies agree with frequency-domain line-shape measurements and femtosecond Coherent anti-Stokes Raman Scattering (CARS) measurements.

  13. Transient Radiation Darkening Features in VISAR Window

    SciTech Connect

    G. D. Stevens; K. J. Moy

    2001-06-01

    We have studied and characterized radiation-induced changes in the index of refraction of materials used in Z experiments. Interferometric measurements of the radiation-induced change in the real part, n, of the complex index of refraction, N = n + iK, have been made in lithium fluoride (LiF), sapphire, and fused silica samples. Our results indicate that the index changes are small, with {delta}n/n {approx} 1 x 10{sup -5}/kGy. In addition, we have characterized the dose dependence of the radiation-induced transient radiation darkening (TRD) of these materials, which is related to K, the imaginary part of the refractive index. We have also measured time-resolved spectral profiles of TRD in LiF and sapphire, and have examined the results in terms of known color centers and possible colloid aggregation.

  14. Transient receptor potential vanilloid 1 and xenobiotics.

    PubMed

    Cuypers, E; Dabrowski, M; Horoszok, L; Terp, G E; Tytgat, J

    2008-04-01

    Over the last couple of years, transient receptor potential vanilloid 1(TRPV1) channels have been a hot topic in ion channel research. Since this research field is still rather new, there is not much known about the working mechanism of TRPV1 and its ligands. Nevertheless, the important physiological role and therapeutic potential are promising. Therefore, extensive research is going on and a lot of natural as well as synthetic compounds are already described. In this review, we briefly give an overview of capsaicin's history and the current knowledge of its working mechanism and physiological role. We discuss the best known plant molecules acting on TRPV1 and highlight the latest discovery in TRPV1 research: animal venoms and toxins acting on TRPV1 channels. In an effort to give the complete image of TRPV1 ligands known today, the most promising synthetic compounds are presented. Finally, we present a novel pharmacophore model describing putative ligand binding domains.

  15. Transient Loschmidt echo in quenched Ising chains

    NASA Astrophysics Data System (ADS)

    Lupo, Carla; Schiró, Marco

    2016-07-01

    We study the response to sudden local perturbations of highly excited quantum Ising spin chains. The key quantity encoding this response is the overlap between time-dependent wave functions, which we write as a transient Loschmidt Echo. Its asymptotics at long time differences contain crucial information about the structure of the highly excited nonequilibrium environment induced by the quench. We compute the echo perturbatively for a weak local quench but for arbitrarily large global quench, using a cumulant expansion. Our perturbative results suggest that the echo decays exponentially, rather than power law as in the low-energy orthogonality catastrophe, a further example of quench-induced decoherence already found in the case of quenched Luttinger liquids. The emerging decoherence scale is set by the strength of the local potential and the bulk excitation energy.

  16. The Transient Response of Cooling Ponds

    NASA Astrophysics Data System (ADS)

    Adams, E. Eric

    1982-10-01

    Cooling ponds are a form of closed cycle cooling used for steam-electric power plants. Because of their thermal inertia they provide an advantage over cooling towers in filtering fluctuations in intake temperature, which results in improved plant efficiency. By using linear systems theory, the transient behavior of various types of ponds is analyzed in response to periodic meteorological conditions (characterized by equilibrium temperature) and plant operational conditions (characterized by condenser temperature rise). Frequency response is expressed in terms of dimensionless ratios involving frequency of input forcing, characteristic hydraulic residence and surface response times, and appropriate mixing parameters. Results are also interpreted with respect to physical design variables, such as pond area, depth, degree of stratification, intake submergence, discharge entrance mixing, condenser flow rate, and temperature rise.

  17. Time lag in transient cosmic accreting sources

    NASA Astrophysics Data System (ADS)

    Bisnovatyi-Kogan, G. S.; Giovannelli, F.

    2017-02-01

    Context. We develop models for time lag between the maxima of the source brightness in different wavelengths during a transient flash of luminosity that is connected with a short-period increase of the mass flux onto the central compact object. Aims: We derive a simple formula for finding the time delay among events in different wavelengths which is valid in general for all disk-accreting cosmic sources. We quantitatively also discuss a model for time-lag formation in active galactic nuclei (AGNs). Methods: In close binaries with accretion disks, the time lag is connected with effects of viscosity that define a radial motion of matter in the accretion disk. In AGN flashes, the infalling matter has a low angular momentum, and the time lag is defined by the free-fall time to the gravitating center. Results: We show the validity of these models by means of several examples of galactic and extragalactic accreting sources.

  18. Transient aero-thermal simulations for TMT

    NASA Astrophysics Data System (ADS)

    Vogiatzis, Konstantinos

    2014-08-01

    Aero-thermal simulations are an integral part of the design process for the Thirty Meter Telescope (TMT). These simulations utilize Computational Solid-Fluid Dynamics (CSFD) to estimate wind jitter and blur, dome and mirror seeing, telescope pointing error due to thermal drift, and to predict thermal effects on performance of components such as the primary mirror segments. Design guidance obtained from these simulations is provided to the Telescope, Enclosure, Facilities and Adaptive Optics groups. Computational advances allow for model enhancements and inclusion of phenomena not previously resolved, such as transient effects on wind loading and thermal seeing due to vent operation while observing or long exposure effects, with potentially different flow patterns corresponding to the beginning and end of observation. Accurate knowledge of the Observatory aero-thermal environment will result in developing reliable look-up tables for effective open loop correction of key active optics system elements, and cost efficient operation of the Observatory.

  19. The Swift Burst and Transient Telescope (BAT)

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard

    2008-01-01

    The Swift Burst and Transient telescope (BAT) has surveyed the entire sky for the last 3.5 years obtaining the first sensitive all sky survey of the 14-195 kev sky. At high galactic latitudes the vast majority of the detected sources are AGN. Since hard x-rays penetrate all but Compton thick obscuring material (Column densities of 1.6324 atms/sq cm) this survey is unbiased with respect to obscuration, host galaxy type, optical , radio or IR properties. We will present results on the broad band x-ray properties, the nature of the host galaxies, the luminosity function and will discuss a few of the optical, IR and x-ray results in detail.

  20. Harnessing quantum transport by transient chaos.

    PubMed

    Yang, Rui; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso; Pecora, Louis M

    2013-03-01

    Chaos has long been recognized to be generally advantageous from the perspective of control. In particular, the infinite number of unstable periodic orbits embedded in a chaotic set and the intrinsically sensitive dependence on initial conditions imply that a chaotic system can be controlled to a desirable state by using small perturbations. Investigation of chaos control, however, was largely limited to nonlinear dynamical systems in the classical realm. In this paper, we show that chaos may be used to modulate or harness quantum mechanical systems. To be concrete, we focus on quantum transport through nanostructures, a problem of considerable interest in nanoscience, where a key feature is conductance fluctuations. We articulate and demonstrate that chaos, more specifically transient chaos, can be effective in modulating the conductance-fluctuation patterns. Experimentally, this can be achieved by applying an external gate voltage in a device of suitable geometry to generate classically inaccessible potential barriers. Adjusting the gate voltage allows the characteristics of the dynamical invariant set responsible for transient chaos to be varied in a desirable manner which, in turn, can induce continuous changes in the statistical characteristics of the quantum conductance-fluctuation pattern. To understand the physical mechanism of our scheme, we develop a theory based on analyzing the spectrum of the generalized non-Hermitian Hamiltonian that includes the effect of leads, or electronic waveguides, as self-energy terms. As the escape rate of the underlying non-attracting chaotic set is increased, the imaginary part of the complex eigenenergy becomes increasingly large so that pointer states are more difficult to form, making smoother the conductance-fluctuation pattern.

  1. Transient Lunar Phenomena: Regularity and Reality

    NASA Astrophysics Data System (ADS)

    Crotts, Arlin P. S.

    2009-05-01

    Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunar surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: ~50% of reports originate from near Aristarchus, ~16% from Plato, ~6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a "feature" as defined). TLP count consistency for these features indicates that ~80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. These reports begin almost exclusively after 1955, when TLPs became widely known and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites to transient outgassing (seen by Apollo and Lunar Prospector instruments). To a high confidence, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs.

  2. Robust Transient Dynamics and Brain Functions

    PubMed Central

    Rabinovich, Mikhail I.; Varona, Pablo

    2011-01-01

    In the last few decades several concepts of dynamical systems theory (DST) have guided psychologists, cognitive scientists, and neuroscientists to rethink about sensory motor behavior and embodied cognition. A critical step in the progress of DST application to the brain (supported by modern methods of brain imaging and multi-electrode recording techniques) has been the transfer of its initial success in motor behavior to mental function, i.e., perception, emotion, and cognition. Open questions from research in genetics, ecology, brain sciences, etc., have changed DST itself and lead to the discovery of a new dynamical phenomenon, i.e., reproducible and robust transients that are at the same time sensitive to informational signals. The goal of this review is to describe a new mathematical framework – heteroclinic sequential dynamics – to understand self-organized activity in the brain that can explain certain aspects of robust itinerant behavior. Specifically, we discuss a hierarchy of coarse-grain models of mental dynamics in the form of kinetic equations of modes. These modes compete for resources at three levels: (i) within the same modality, (ii) among different modalities from the same family (like perception), and (iii) among modalities from different families (like emotion and cognition). The analysis of the conditions for robustness, i.e., the structural stability of transient (sequential) dynamics, give us the possibility to explain phenomena like the finite capacity of our sequential working memory – a vital cognitive function –, and to find specific dynamical signatures – different kinds of instabilities – of several brain functions and mental diseases. PMID:21716642

  3. LONG GAMMA-RAY TRANSIENTS FROM COLLAPSARS

    SciTech Connect

    Woosley, S. E.; Heger, Alexander E-mail: alex@physics.umn.edu

    2012-06-10

    In the collapsar model for common gamma-ray bursts (GRBs), the formation of a centrifugally supported disk occurs during the first {approx}10 s following the collapse of the iron core in a massive star. This only occurs in a small fraction of massive stellar deaths, however, and requires unusual conditions. A much more frequent occurrence could be the death of a star that makes a black hole and a weak or absent outgoing shock, but in a progenitor that only has enough angular momentum in its outermost layers to make a disk. We consider several cases where this is likely to occur-blue supergiants with low mass-loss rates, tidally interacting binaries involving either helium stars or giant stars, and the collapse to a black hole of very massive pair-instability supernovae. These events have in common the accretion of a solar mass or so of material through a disk over a period much longer than the duration of a common GRB. A broad range of powers is possible, 10{sup 47}-10{sup 50} erg s{sup -1}, and this brightness could be enhanced by beaming. Such events were probably more frequent in the early universe where mass-loss rates were lower. Indeed, this could be one of the most common forms of gamma-ray transients in the universe and could be used to study first generation stars. Several events could be active in the sky at any one time. Recent examples of this sort of event may have been the Swift transients Sw-1644+57, Sw-2058+0516, and GRB 101225A.

  4. TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY

    SciTech Connect

    Crotts, Arlin P. S.

    2009-05-20

    Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunar surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: {approx}50% of reports originate from near Aristarchus, {approx}16% from Plato, {approx}6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a 'feature' as defined). TLP count consistency for these features indicates that {approx}80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. These reports begin almost exclusively after 1955, when TLPs became widely known and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites to transient outgassing (seen by Apollo and Lunar Prospector instruments). To a high confidence, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs.

  5. Transient ulnar artery compression facilitates transradial access

    PubMed Central

    Zhou, Zhi-ming; Yan, Zhen-xian; Nie, Bin; Guo, Yong-he; Zhou, Yu-jie

    2016-01-01

    Abstract Background: Unsuccessful radial artery puncture is one of the important causes of transradial procedure failure. Ulnar artery compression made the radial artery pulse stronger. Whether it would make transradial access easier, however, is uncertain. Methods: A prospective randomized controlled trial was conducted among 446 patients who planned for transradial cardiac catheterization. Patients were randomized to receiving either transient ulnar artery compression (UC) or standard treatment (standard) for half an hour prior to needle insertion (217 UC, 229 standard). The diameters of right radial artery and ulnar artery were measured by ultrasound on admission and before artery puncture. Primary endpoints included the number of attempts to access, the rate of first-pass success, and time for a successful access. Secondary endpoints were the number of difficult procedures, and the incidence of puncture failure. Results: The diameters of radial artery were larger after half an hour's ulnar artery compression, but there were no obvious changes in that of ulnar artery. As compared with standard group, the number of attempts was significantly decreased (1.42 ± 1.10 vs 2.97 ± 2.38, P <0.001), and the rate of first-pass success was greatly enhanced (73.27% vs 57.64%, P <0.001) in UC group. Meanwhile, the time for access was decreased (59 ± 15 seconds vs 71 ± 18 seconds, P <0.001) with UC. In addition, the proportion of difficult procedures of UC group was less than that of standard group (4.61% vs 10.92%, P = 0.013). No significant differences were found in failure rates of sheath insertion and puncture between the 2 groups. Conclusion: Transient ulnar artery compression enhances the efficacy and feasibility of radial artery intubatton in transradial catheterization. PMID:27902608

  6. Impaired picture recognition in transient epileptic amnesia.

    PubMed

    Dewar, Michaela; Hoefeijzers, Serge; Zeman, Adam; Butler, Christopher; Della Sala, Sergio

    2015-01-01

    Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Transient epileptic amnesia is often associated with the rapid decline in recall of new information over hours to days (accelerated long-term forgetting - 'ALF'). It remains unknown how recognition memory is affected in TEA over time. Here, we report a systematic study of picture recognition in patients with TEA over the course of one week. Sixteen patients with TEA and 16 matched controls were presented with 300 photos of everyday life scenes. Yes/no picture recognition was tested 5min, 2.5h, 7.5h, 24h, and 1week after picture presentation using a subset of target pictures as well as similar and different foils. Picture recognition was impaired in the patient group at all test times, including the 5-minute test, but it declined normally over the course of 1week. This impairment was associated predominantly with an increased false alarm rate, especially for similar foils. High performance on a control test indicates that this impairment was not associated with perceptual or discrimination deficits. Our findings suggest that, at least in some TEA patients with ALF in verbal recall, picture recognition does not decline more rapidly than in controls over 1week. However, our findings of an early picture recognition deficit suggest that new visual memories are impoverished after minutes in TEA. This could be the result of deficient encoding or impaired early consolidation. The early picture recognition deficit observed could reflect either the early stages of the process that leads to ALF or a separable deficit of anterograde memory in TEA. Lastly, our study suggests that at least some patients with TEA are prone to falsely recognizing new everyday visual information that they have not in fact seen previously. This deficit, alongside their ALF in free recall, likely affects everyday memory performance.

  7. Dynamische Satzgenerierung und Sprachausgabe für einen mobilen Serviceroboter

    NASA Astrophysics Data System (ADS)

    Parlitz, Christopher; Amann, Bernd; Hägele, Martin

    Die vorliegende Arbeit befasst sich mit der Entwicklung einer Sprachausgabe für ein mobiles Robotersystem. Dazu wurde zum einen ein auf die Anwendung zugeschittenes Text-To-Speech Verfahren und zum anderen eine Grammatik, die eine dynamische Satzgenerierung ermöglicht, implementiert. Die Verfahren arbeiten unabhängig voneinander und können daher auch gegen andere Komponenten ausgetauscht werden. Die Programme wurden als Client-Server Applikationen programmiert, um möglichst flexibel die Sprachausgabe einsetzen zu können.

  8. Biologie statt Philosophie? Evolutionäre Kulturerklärungen und ihre Grenzen

    NASA Astrophysics Data System (ADS)

    Illies, Christian

    Vor über siebzig Jahren fand man in einer Höhle nahe Hohlenstein-Stadel, im heutigen Baden-Württemberg, eine Frau, die keiner bekannten Spezies und nicht einmal eindeutig den Hominiden zugeordnet werden konnte. Wegen ihres Aussehens wurde sie schon bald als "Löwenfrau“ bekannt (unterdessen wird sie als "Löwenmensch“ bezeichnet, da die in solchen Fragen Klarheit schaffenden Geschlechtsteile bei der Figur fehlen und in Zeiten von gender mainstreaming derartige Festlegungen gerne vermieden werden), denn sie hatte eine menschlich-aufrechte, unbehaarte Gestalt mit weiblichen Rundungen, aber zugleich eine Mähne, sowie Augen, Ohren und Schnauze eines Löwen. Eine sehr weitläufige Verwandte des Minotaurus, so schien es, und doch wesentlich älter als alle Bewohner des Olymps, denn vermutlich wurde die knapp 30 cm große Skulptur bereits in der Altsteinzeit vor etwa 32.000 Jahren aus Mammut-Elfenbein geschnitzt. Wir wissen nicht, ob sie kultischen Zwecken diente oder ein Kind mit ihr spielte, ob sie als Glücksbringer für die Jagd oder als Schamanin mit Löwenmaske verehrt und gefürchtet wurde. Aber die Löwenfrau legt nahe, dass der Mensch schon im Morgendämmern seiner Kultur über die eigene Nähe, aber auch Distanz zum Tier nachgedacht haben muss. Die Frage nach der menschlichen Selbstverortung begegnet uns in dieser Figur, und sie bestimmt viele Zeugnisse menschlichen Nachdenkens, welche uns die Altertumswissenschaften vorlegen. Mit dem Begriff "animal rationale“, wie er unter Bezug auf Aristoteles geprägt wurde, findet sie schließlich ihre klassische, für das Abendland lange Zeit maßgebliche Antwort: Der Mensch als Tier, dessen spezifisches Merkmal die Vernunftbegabtheit ist, die ihn zugleich von allen anderen Tieren abgrenzt und über sie stellt. Aber wo genau verläuft die Grenze? Und wie kann der Mensch beides zugleich sein? Die aristotelische Definition beantwortet diese Fragen nach der Doppelnatur nicht, sondern erhebt das offene R

  9. Vom Referat bis zur Examensarbeit: Naturwissenschaftliche Texte perfekt verfassen und gestalten

    NASA Astrophysics Data System (ADS)

    Kremer, Bruno P.

    Welches Thema eignet sich für mein Referat oder meine Seminararbeit? Wie sammle ich Stoff? Wie gliedere ich den Text? Bruno P. Kremer beantwortet auf nur 200 Seiten alle wichtigen Fragen zur wissenschaftlichen Arbeit in den naturwissenschaftlichen Fächern. Dabei beschränkt er sich auf das für Studenten und Schüler wirklich notwendige Wissen und lässt jeglichen unnützen Ballast beiseite. Dieser praktische Ratgeber verhilft Ihnen zur erfolgreichen wissenschaftlichen Arbeit - vom Referat bis zur Examensarbeit.

  10. Wer entdeckte die Allgemeine Relativitätstheorie? Prioritätsstreit zwischen Hilbert und Einstein

    NASA Astrophysics Data System (ADS)

    Sommer, Klaus P.

    2005-09-01

    Im November 1915 arbeiteten Albert Einstein und David Hilbert an den Feldgleichungen der Gravitationstheorie. Im Jahre 1997 behaupteten die Wissenschaftshistoriker Corry, Renn und Stachel in einer viel beachteten Arbeit, Hilbert habe die entscheidenden Formeln von Einstein gestohlen. Grundlage ihrer Argumentation war eine wieder gefundene Korrekturfahne von Hilberts entscheidender Arbeit. Die Physikhistorikerin Daniela Wuensch bringt jedoch detaillierte Argumente dafür vor, dass die entscheidende Quelle, nämlich die Korrekturfahne, in neuerer Zeit manipuliert worden ist, um Einsteins Priorität unangetastet zu lassen. Einstein bleibt aber der Entdecker der Allgemeinen Relativitätstheorie.

  11. Multiscale Transient Signal Detection: Localizing Transients in Geodetic Data Through Wavelet Transforms and Sparse Estimation Techniques

    NASA Astrophysics Data System (ADS)

    Riel, B.; Simons, M.; Agram, P.

    2012-12-01

    Transients are a class of deformation signals on the Earth's surface that can be described as non-periodic accumulation of strain in the crust. Over seismically and volcanically active regions, these signals are often challenging to detect due to noise and other modes of deformation. Geodetic datasets that provide precise measurements of surface displacement over wide areas are ideal for exploiting both the spatial and temporal coherence of transient signals. We present an extension to the Multiscale InSAR Time Series (MInTS) approach for analyzing geodetic data by combining the localization benefits of wavelet transforms (localizing signals in space) with sparse optimization techniques (localizing signals in time). Our time parameterization approach allows us to reduce geodetic time series to sparse, compressible signals with very few non-zero coefficients corresponding to transient events. We first demonstrate the temporal transient detection by analyzing GPS data over the Long Valley caldera in California and along the San Andreas fault near Parkfield, CA. For Long Valley, we are able to resolve the documented 2002-2003 uplift event with greater temporal precision. Similarly for Parkfield, we model the postseismic deformation by specific integrated basis splines characterized by timescales that are largely consistent with postseismic relaxation times. We then apply our method to ERS and Envisat InSAR datasets consisting of over 200 interferograms for Long Valley and over 100 interferograms for Parkfield. The wavelet transforms reduce the impact of spatially correlated atmospheric noise common in InSAR data since the wavelet coefficients themselves are essentially uncorrelated. The spatial density and extended temporal coverage of the InSAR data allows us to effectively localize ground deformation events in both space and time with greater precision than has been previously accomplished.

  12. Electromagnetic transients program (EMTP): Volume 4, Workbook IV (TACS) (Transients Analysis of Control Systems): Final report

    SciTech Connect

    Lasseter, R.H.

    1989-06-01

    This workbook represents an introduction to the use of TACS (Transients Analysis of Control Systems) in the EMTP. The material progresses from an overview of basic TACS concepts and components to a detailed HVDC model. The following application of TACS are covered: a variable load problem, static Var systems, thyristor models, TCR, basic HVDC models and a detailed HVDC model. Complete data files are given for most examples.

  13. Explosive and Radio-Selected Transients: Transient Astronomy with Square Kilometre Array and its Precursors

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Anupama, G. C.; Arun, K. G.; Iyyani, Shabnam; Misra, Kuntal; Narasimha, D.; Ray, Alak; Resmi, L.; Roy, Subhashis; Sutaria, Firoza

    2016-12-01

    With the high sensitivity and wide-field coverage of the Square Kilometre Array (SKA), large samples of explosive transients are expected to be discovered. Radio wavelengths, especially in commensal survey mode, are particularly well-suited for uncovering the complex transient phenomena. This is because observations at radio wavelengths may suffer less obscuration than in other bands (e.g. optical/IR or X-rays) due to dust absorption. At the same time, multiwaveband information often provides critical source classification rapidly than possible with only radio band data. Therefore, multiwaveband observational efforts with wide fields of view will be the key to progress of transients astronomy from the middle 2020s offering unprecedented deep images and high spatial and spectral resolutions. Radio observations of Gamma Ray Bursts (GRBs) with SKA will uncover not only much fainter bursts and verifying claims of sensitivity-limited population versus intrinsically dim GRBs, they will also unravel the enigmatic population of orphan afterglows. The supernova rate problem caused by dust extinction in optical bands is expected to be lifted in the SKA era. In addition, the debate of single degenerate scenario versus double degenerate scenario will be put to rest for the progenitors of thermonuclear supernovae, since highly sensitive measurements will lead to very accurate mass loss estimation in these supernovae. One also expects to detect gravitationally lensed supernovae in far away Universe in the SKA bands. Radio counterparts of the gravitational waves are likely to become a reality once SKA comes online. In addition, SKA is likely to discover various new kinds of transients.

  14. Selective ion changes during spontaneous mitochondrial transients in intact astrocytes.

    PubMed

    Azarias, Guillaume; Chatton, Jean-Yves

    2011-01-01

    The bioenergetic status of cells is tightly regulated by the activity of cytosolic enzymes and mitochondrial ATP production. To adapt their metabolism to cellular energy needs, mitochondria have been shown to exhibit changes in their ionic composition as the result of changes in cytosolic ion concentrations. Individual mitochondria also exhibit spontaneous changes in their electrical potential without altering those of neighboring mitochondria. We recently reported that individual mitochondria of intact astrocytes exhibit spontaneous transient increases in their Na(+) concentration. Here, we investigated whether the concentration of other ionic species were involved during mitochondrial transients. By combining fluorescence imaging methods, we performed a multiparameter study of spontaneous mitochondrial transients in intact resting astrocytes. We show that mitochondria exhibit coincident changes in their Na(+) concentration, electrical potential, matrix pH and mitochondrial reactive oxygen species production during a mitochondrial transient without involving detectable changes in their Ca(2+) concentration. Using widefield and total internal reflection fluorescence imaging, we found evidence for localized transient decreases in the free Mg(2+) concentration accompanying mitochondrial Na(+) spikes that could indicate an associated local and transient enrichment in the ATP concentration. Therefore, we propose a sequential model for mitochondrial transients involving a localized ATP microdomain that triggers a Na(+)-mediated mitochondrial depolarization, transiently enhancing the activity of the mitochondrial respiratory chain. Our work provides a model describing ionic changes that could support a bidirectional cytosol-to-mitochondria ionic communication.

  15. [THERAPY OF TRANSIENT LACTASE INSUFFICIENCY OF CHILDREN IN PECTORAL AGE].

    PubMed

    Marushko, Yu V; Iovitsa, T V

    2015-01-01

    Thus, we have discovered that the children of the first half-year of life have different degrees of severity of transient lactase insufficiency basing on the results of hydrogen respiratory test. It was set that the starting dose of enzyme lactase must depend on the degree of severity of displays of transient lactase insufficiency, taking into account the indexes of hydrogen respiratory test.

  16. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Kilpatrick, C. D.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2017-02-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN), the ATLAS project (ATel #8680), and the Pan-STARRS Survey for Transients (PSST).

  17. Spectroscopic Classifications of Optical Transients with SOAR/Goodman

    NASA Astrophysics Data System (ADS)

    Miller, J. A.; Hounsell, R. A.; Pan, Y.-C.; Kilpatrick, C. D.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report a classification of optical transients from spectroscopic observations with the Goodman spectrograph on the SOAR telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN) and the Pan-STARRS Survey for Transients (PSST).

  18. Transient water stress in a vegetation canopy - Simulations and measurements

    NASA Technical Reports Server (NTRS)

    Carlson, Toby N.; Belles, James E.; Gillies, Robert R.

    1991-01-01

    Consideration is given to observational and modeling evidence of transient water stress, the effects of the transpiration plateau on the canopy radiometric temperature, and the factors responsible for the onset of the transpiration plateau, such as soil moisture. Attention is also given to the point at which the transient stress can be detected by remote measurement of surface temperature.

  19. iPTF discovery and identification of bright transients

    NASA Astrophysics Data System (ADS)

    Kupfer, Thomas; Ho, Anna; Karamehmetoglu, Emir; Petrushevska, Tanja; Adams, Scott; Neill, James D.; Walters, Richard; Cannella, Chris; Blagorodnova, Nadejda; Yan, Lin; Kulkarni, Shri

    2017-02-01

    The intermediate Palomar Transient Factory (ATel #4807) reports the discovery of the following bright transients. We report as ATel alerts all objects brighter than 19 mag. Our discoveries are reported in two filters: sdss-g and Mould-I, denoted as g, and I. Both are in the AB magnitude system.

  20. iPTF discovery and classification of bright transients

    NASA Astrophysics Data System (ADS)

    Blagorodnova, Nadejda; Ho, Anna; Karamehmetoglu, Emir; Petrushevska, Tanja; Kupfer, Thomas; Adams, Scott; Cannella, Chris; Yan, Lin; Kasliwal, Mansi; Kulkarni, Shri; Neill, James D.; Walters, Richard

    2017-01-01

    The intermediate Palomar Transient Factory (ATel #4807) reports the discovery of the following bright transients. We report as ATel alerts all objects brighter than 19 mag. Our discoveries are reported in three filters: sdss-r, Mould-R and Mould-I, denoted as g, r and i. All three are in the AB magnitude system.

  1. Centrifugal Modelling of Transient Water Flow in Earth Embankments.

    DTIC Science & Technology

    1980-05-07

    Redshaw [10] in their recent book and the transient flow net technique described by Cedergren Approximate Solutions The solution of the transient flow...and Foundation Engineering, Paris, Vol. II, pp. 551-554. 3. Cedergren , H.R., Seepage, Drainage, and Flow Nets, 2nd Ed., New York, John Wiley & Sons

  2. Transient flow thrust prediction for an ejector propulsion concept

    NASA Technical Reports Server (NTRS)

    Drummond, Colin K.

    1989-01-01

    A method for predicting transient thrust augmenting ejector characteristics is introduced. The analysis blends classic self-similar turbulent jet descriptions with a mixing region control volume analysis to predict transient effects in a new way. Details of the theoretical foundation, the solution algorithm, and sample calculations are given.

  3. Static and Transient Cavitation Threshold Measurements for Mercury

    SciTech Connect

    Moraga, F.; Taleyarkhan, R.P.

    1999-11-14

    Transient and static cavitation thresholds for mercury as a function of the cover gas (helium or air), and pressure are reported. Both static and transient cavitation onset pressure thresholds increase linearly with cover gas pressure. Additionally, the cavitation thresholds as a function of dissolved gases were also measured and are reported.

  4. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Transient investment companies. 270.3a-2 Section 270.3a-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment...

  5. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Transient investment companies. 270.3a-2 Section 270.3a-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment...

  6. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Transient investment companies. 270.3a-2 Section 270.3a-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment...

  7. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Transient investment companies. 270.3a-2 Section 270.3a-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment...

  8. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Transient investment companies. 270.3a-2 Section 270.3a-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment...

  9. Network Connectivity for Permanent, Transient, Independent, and Correlated Faults

    NASA Technical Reports Server (NTRS)

    White, Allan L.; Sicher, Courtney; henry, Courtney

    2012-01-01

    This paper develops a method for the quantitative analysis of network connectivity in the presence of both permanent and transient faults. Even though transient noise is considered a common occurrence in networks, a survey of the literature reveals an emphasis on permanent faults. Transient faults introduce a time element into the analysis of network reliability. With permanent faults it is sufficient to consider the faults that have accumulated by the end of the operating period. With transient faults the arrival and recovery time must be included. The number and location of faults in the system is a dynamic variable. Transient faults also introduce system recovery into the analysis. The goal is the quantitative assessment of network connectivity in the presence of both permanent and transient faults. The approach is to construct a global model that includes all classes of faults: permanent, transient, independent, and correlated. A theorem is derived about this model that give distributions for (1) the number of fault occurrences, (2) the type of fault occurrence, (3) the time of the fault occurrences, and (4) the location of the fault occurrence. These results are applied to compare and contrast the connectivity of different network architectures in the presence of permanent, transient, independent, and correlated faults. The examples below use a Monte Carlo simulation, but the theorem mentioned above could be used to guide fault-injections in a laboratory.

  10. Transient platoon aerodynamics and bluff body flows

    NASA Astrophysics Data System (ADS)

    Tsuei, Lun

    There are two components of this experimental work: transient vehicle platoon aerodynamics and bluff-body flows. The transient aerodynamic effects in a four-vehicle platoon during passing maneuvers and in-line oscillations are investigated. A vehicle model is moved longitudinally parallel to a four-car platoon to simulate passing maneuvers. The drag and side forces experienced by each platoon member are measured using strain gauge balances. The resulting data are presented as dimensionless coefficients. It is shown that each car in the platoon experiences a repulsive side force when the passing vehicle is in the neighborhood of its rear half. The side force reverses its direction and becomes an attractive force when the passing vehicle moves to the neighborhood of its front half. The drag force experienced by each platoon member is increased when the passing vehicle is in its proximity. The effects of the lateral spacing and relative velocity between the platoon and the passing vehicle, as well as the shape of the passing vehicle, are also investigated. Similar trends are observed in simulations of both a vehicle passing a platoon and a platoon overtaking a vehicle. During the in-line oscillation experiments, one of the four platoon members is forced to undergo longitudinal periodic motions. The drag force experienced by each platoon member is determined simultaneously during the oscillations. The effects of the location of the oscillating vehicle, the shape of the vehicles and the displacement and velocity amplitudes of the oscillation are examined. The results from the transient conditions are compared to those from the steady tests in the same setup. In the case of a four-car platoon, the drag variations experienced by the vehicles adjacent to the oscillating vehicle are discussed using a cavity model. It is found that when the oscillating car moves forward and approaches its upstream neighbor, itself and its downstream neighbor experiences an increased drag

  11. Transient sodium current at subthreshold voltages: activation by EPSP waveforms.

    PubMed

    Carter, Brett C; Giessel, Andrew J; Sabatini, Bernardo L; Bean, Bruce P

    2012-09-20

    Tetrodotoxin (TTX)-sensitive sodium channels carry large transient currents during action potentials and also "persistent" sodium current, a noninactivating TTX-sensitive current present at subthreshold voltages. We examined gating of subthreshold sodium current in dissociated cerebellar Purkinje neurons and hippocampal CA1 neurons, studied at 37°C with near-physiological ionic conditions. Unexpectedly, in both cell types small voltage steps at subthreshold voltages activated a substantial component of transient sodium current as well as persistent current. Subthreshold EPSP-like waveforms also activated a large component of transient sodium current, but IPSP-like waveforms engaged primarily persistent sodium current with only a small additional transient component. Activation of transient as well as persistent sodium current at subthreshold voltages produces amplification of EPSPs that is sensitive to the rate of depolarization and can help account for the dependence of spike threshold on depolarization rate, as previously observed in vivo.

  12. MASTER-SAAO: optical transient detections and followups

    NASA Astrophysics Data System (ADS)

    Buckley, David A. H.; Lipunov, Vladimir; Gorbovskoy, Evgeny; Gress, Oleg; Potter, Stephen Brian; Kniazev, Alexei

    2015-08-01

    Following its installation at Sutherland in late Dec 2014, the SAAO node of the MASTER optical transient detection network has been busy discovering new optical transient sources and following up on other transient triggers. This is the first general transient detection system to be installed at SAAO, allowing for the rapid detection and followup of the likes of CVs, GRBs, SNe and flaring blazars. Up to mid-March 2015, some 40 transients have been discovered by MASTER-SAAO. In addition several Gamma Ray Burst (GRB) follow-up observations were conducted with MASTER-SAAO, leading to the identification of optical counterparts and the determination of the afterglow decay light curves for two of them, and upper limits for the rest. We discuss the MASTER-SAAO system and future plans to automate followup observations with SALT and a new 1.0 m robotic telescope at SAAO.

  13. A New Adaptive Mother Wavelet for Electromagnetic Transient Analysis

    NASA Astrophysics Data System (ADS)

    Guillén, Daniel; Idárraga-Ospina, Gina; Cortes, Camilo

    2016-01-01

    Wavelet Transform (WT) is a powerful technique of signal processing, its applications in power systems have been increasing to evaluate power system conditions, such as faults, switching transients, power quality issues, among others. Electromagnetic transients in power systems are due to changes in the network configuration, producing non-periodic signals, which have to be identified to avoid power outages in normal operation or transient conditions. In this paper a methodology to develop a new adaptive mother wavelet for electromagnetic transient analysis is proposed. Classification is carried out with an innovative technique based on adaptive wavelets, where filter bank coefficients will be adapted until a discriminant criterion is optimized. Then, its corresponding filter coefficients will be used to get the new mother wavelet, named wavelet ET, which allowed to identify and to distinguish the high frequency information produced by different electromagnetic transients.

  14. Analysis and Simulations of Space Radiation Induced Single Event Transients

    NASA Astrophysics Data System (ADS)

    Perez, Reinaldo

    2016-05-01

    Spacecraft electronics are affected by the space radiation environment. Among the different types of radiation effects that can affect spacecraft electronics is the single event transients. The space environment is responsible for many of the single event transients which can upset the performance of the spacecraft avionics hardware. In this paper we first explore the origins of single event transients, then explore the modeling of a single event transient in digital and analog circuit. The paper also addresses the concept of crosstalk that could develop among digital circuits in the present of a SET event. The paper ends with a brief discussion of SET hardening. The goal of the paper is to provide methodologies for assessing single event transients and their effects so that spacecraft avionics engineers can develop either hardware or software countermeasures in their designs.

  15. Ultrafast transient absorption spectroscopy: principles and application to photosynthetic systems.

    PubMed

    Berera, Rudi; van Grondelle, Rienk; Kennis, John T M

    2009-01-01

    The photophysical and photochemical reactions, after light absorption by a photosynthetic pigment-protein complex, are among the fastest events in biology, taking place on timescales ranging from tens of femtoseconds to a few nanoseconds. The advent of ultrafast laser systems that produce pulses with femtosecond duration opened up a new area of research and enabled investigation of these photophysical and photochemical reactions in real time. Here, we provide a basic description of the ultrafast transient absorption technique, the laser and wavelength-conversion equipment, the transient absorption setup, and the collection of transient absorption data. Recent applications of ultrafast transient absorption spectroscopy on systems with increasing degree of complexity, from biomimetic light-harvesting systems to natural light-harvesting antennas, are presented. In particular, we will discuss, in this educational review, how a molecular understanding of the light-harvesting and photoprotective functions of carotenoids in photosynthesis is accomplished through the application of ultrafast transient absorption spectroscopy.

  16. Transient sodium current at subthreshold voltages: activation by EPSP waveforms

    PubMed Central

    Carter, Brett C.; Giessel, Andrew J.; Sabatini, Bernardo L.; Bean, Bruce P.

    2012-01-01

    Summary Tetrodotoxin (TTX)-sensitive sodium channels carry large transient currents during action potentials and also “persistent” sodium current, a non-inactivating TTX-sensitive current present at subthreshold voltages. We examined gating of subthreshold sodium current in dissociated cerebellar Purkinje neurons and hippocampal CA1 neurons, studied at 37 °C with near-physiological ionic conditions. Unexpectedly, in both cell types small voltage steps at subthreshold voltages activated a substantial component of transient sodium current as well as persistent current. Subthreshold EPSP-like waveforms also activated a large component of transient sodium current, but IPSP-like waveforms engaged primarily persistent sodium current with only a small additional transient component. Activation of transient as well as persistent sodium current at subthreshold voltages produces amplification of EPSPs that is sensitive to the rate of depolarization and can help account for the dependence of spike threshold on depolarization rate, as previously observed in vivo. PMID:22998875

  17. Transient High-Pressure Fuel Injection

    NASA Astrophysics Data System (ADS)

    Jarrahbashi, Dorrin

    Break-up and atomization of liquid fuel jet during transient injection process has a significant effect on the Diesel engine combustion efficiency and pollution. The mechanisms responsible for liquid jet instability and break-up at high pressure, during the transient start-up and steady mass flux periods, has been investigated using Navier-Stokes and level-set computations. Via post-processing, the role of vorticity dynamics is examined and shown to reveal crucial new insights. An unsteady, axisymmetric full-jet case is solved. Then, a less computationally intensive case is studied with a segment of the jet core undergoing temporal instability; agreement with the full-jet calculation is satisfactory justifying the segment analysis for three-dimensional computation. The results for surface-shape development are in agreement with experimental observations and other three-dimensional computations; the initial, axisymmetric waves at the jet surface created by Kelvin-Helmholtz instability distort to cone shapes; next, three-dimensional character develops through an azimuthal instability that leads to the creation of streamwise vorticity, lobe shapes on the cones, and formation of liquid ligaments which extend from lobes on the cones. The cause of this azimuthal instability has been widely described as a Rayleigh-Taylor instability. However, additional and sometimes more important causes are identified here. Counter-rotating, streamwise vortices within and around the ligaments show a relationship in the instability behavior for jets flowing into like-density fluid; thus, density difference cannot explain fully the three-dimensional instability as previously suggested. Furthermore, the formation of ligaments that eventually break into droplets and the formation of streamwise vorticity are caused by the same vortical dynamics. Waviness is identified on the ligaments which should result in droplet formation. The nonlinear development of the shorter azimuthal waves and

  18. Stress induces transient auditory hypersensitivity in rats.

    PubMed

    Mazurek, Birgit; Haupt, Heidemarie; Joachim, Ricarda; Klapp, Burghard F; Stöver, Timo; Szczepek, Agnieszka J

    2010-01-01

    Exposure to harsh environment induces stress reactions that increase probability of survival. Stress influences the endocrine, nervous and immune systems and affects the functioning of a variety of organs. Numerous researchers demonstrated that a 24-h exposure to an acoustic rodent repellent provokes stress reaction in exposed animals. In addition to the activated hypothalamic-pituitary-adrenal (HPA) axis, exposed animals had pathological reactions in the reproductive organs, bronchia and skin. Here, we examined the effect of above stress model on the auditory system of Wistar rats. We found that 24-h stress decreases the thresholds and increases the amplitudes of auditory brainstem responses and distortion product otoacoustic emissions. Resultant auditory hypersensitivity was transient and most pronounced between 3 and 6h post-stress, returning to control levels one week later. The concentration of corticosterone and tumor necrosis factor alpha was systemically elevated in stressed animals between 3 and 6h post-stress, confirming the activation of the HPA axis. In addition, expression of the HPA-axis-associated genes: glucocorticoid receptor (GR) and hypoxia-inducible factor 1 alpha (Hif1a) was modulated in the auditory tissues. In detail, in the inferior colliculus, we found an up-regulation of GR mRNA 3h post-stress and continuous up-regulation of Hif1a up to 24h post-stress. In the spiral ganglion, we found no differences in gene expression between stressed and control animals. In the organ of Corti, expression of GR mRNA remained stable, whereas that of Hif1a was significantly down-regulated one week after stress. In addition, the expression of an outer hair cell marker prestin was significantly up-regulated 6h post-stress. We conclude that 24-h stress induces transient hypersensitivity of the auditory system and modulates gene expression in a tissue-specific manner. Stress-induced auditory hypersensitivity could have evolutionary consequence by giving animals

  19. Transient Point Infiltration In The Unsaturated Zone

    NASA Astrophysics Data System (ADS)

    Buecker-Gittel, M.; Mohrlok, U.

    The risk assessment of leaking sewer pipes gets more and more important due to urban groundwater management and environmental as well as health safety. This requires the quantification and balancing of transport and transformation processes based on the water flow in the unsaturated zone. The water flow from a single sewer leakage could be described as a point infiltration with time varying hydraulic conditions externally and internally. External variations are caused by the discharge in the sewer pipe as well as the state of the leakage itself. Internal variations are the results of microbiological clogging effects associated with the transformation processes. Technical as well as small scale laboratory experiments were conducted in order to investigate the water transport from an transient point infiltration. From the technical scale experiment there was evidence that the water flow takes place under transient conditions when sewage infiltrates into an unsaturated soil. Whereas the small scale experiments investigated the hydraulics of the water transport and the associated so- lute and particle transport in unsaturated soils in detail. The small scale experiment was a two-dimensional representation of such a point infiltration source where the distributed water transport could be measured by several tensiometers in the soil as well as by a selective measurement of the discharge at the bottom of the experimental setup. Several series of experiments were conducted varying the boundary and initial con- ditions in order to derive the important parameters controlling the infiltration of pure water from the point source. The results showed that there is a significant difference between the infiltration rate in the point source and the discharge rate at the bottom, that could be explained by storage processes due to an outflow resistance at the bottom. This effect is overlayn by a decreasing water content decreases over time correlated with a decreasing infiltration

  20. Detecting Strain Transients in the Salton Trough (Invited)

    NASA Astrophysics Data System (ADS)

    McGuire, J. J.; Segall, P.; Herring, T.

    2009-12-01

    The Salton Trough region routinely experiences fault creep transients with time-scales of days to weeks, and previous studies have documented a temporal relationship between these aseimsic transients and earthquake swarms. The Plate Boundary Observatory has greatly increased the density of continuous geodetic data available in the Salton Trough, and we are analyzing this dataset to detect time periods when aseismic transients occurred in the Salton Trough. We are searching the daily GPS solutions for the time period from 2005-2009 for transients using Kalman Filter based detection algorithm called the Network Strain Filter [Ohtani, McGuire, and Segall, 2009]. The NSF solves for estimates of the secular velocity field and a time-vary transient displacement field that are expanded in basis functions. We utilize two dimensional wavelets as the basis functions. Spatial smoothing of the transient and secular velocity field are achieved by weighting the prior covariance matrix elements based on the scale of the individual wavelet basis. Site specific colored noise (seasonal terms, etc) is estimated as an random walk for each component. The vast majority of the Salton Trough GPS records are well explained by a combination of secular velocity and seasonal terms. However, we do find two spatially coherent transient episodes visible at multiple stations in the GPS data. The largest occurs near the southern extension of the Superstition Hills fault (Weinert Fault) during the second half of 2007. About 1 cm of extra motion to the northwest is observed at station P494, P496, and P497. The time scale of this transient is a few months. A second, smaller more abrupt transient is observed at stations P500 and P744 at the time of the February 2008 earthquake swarm at Cerro Prieto. We are investigating whether these two transients can be explained by slip on the Superstition Hills and Imperial faults respectively.

  1. Physik gestern und heute Suprafluidität - Von den Schwierigkeiten einer Messung

    NASA Astrophysics Data System (ADS)

    Sichau, Christian

    2003-03-01

    Der Vater der Tieftemperaturphysik, Heike Kammerlingh Onnes, benötigte zu Beginn des 20. Jahrhunderts für die Verflüssigung von wenigen Litern Heliums noch mehrere Jahre, eine riesige Apparatur und viel Geld. Heute gelingt dies routinemäßig. Die Untersuchung der Materie bei tiefen Temperaturen, insbesondere zur Suprafluidität, bietet viele Überraschungen.

  2. Rosazea-Management: Update über allgemeine Maßnahmen und topische Therapieoptionen.

    PubMed

    Schaller, M; Schöfer, H; Homey, B; Hofmann, M; Gieler, U; Lehmann, P; Luger, T A; Ruzicka, T; Steinhoff, M

    2016-12-01

    Obwohl bislang für die Rosazea keine kurative Therapie besteht, können verschiedene Optionen zur Behandlung der Symptome und zur Vorbeugung von Exazerbationen empfohlen werden. Neben Selbsthilfemaßnahme wie der Vermeidung von Triggerfaktoren und einer geeigneten Hautpflege sollte das Rosazea-Management bei Patienten mit erythematöser und leichter bis schwerer papulopustulöser Rosazea die Anwendung topischer Präparate als First-Line-Therapie umfassen. Da Überlappungen der charakteristischen Rosazea-Symptome im klinischen Alltag die Regel sind, sollte die medikamentöse Therapie auf die individuellen Symptome zugeschnitten werden; auch eine Kombinationstherapie kann erforderlich sein. Zu den für die Behandlung der Hauptsymptome der Rosazea zugelassenen Wirkstoffen gehören Brimonidin gegen das Erythem sowie Ivermectin, Metronidazol oder Azelainsäure gegen entzündliche Läsionen. Ihre Wirksamkeit wurde in zahlreichen validen, gut kontrollierten Studien belegt. Darüber hinaus existieren verschiedene nicht zugelassene topische Behandlungsmöglichkeiten, deren Wirksamkeit und Sicherheit noch in größeren, kontrollierten Studien zu untersuchen ist.

  3. Matthias Falter und die frühe Halbleitertechnik in der DDR

    NASA Astrophysics Data System (ADS)

    Dittmann, Frank

    Nach einer ganzen Reihe von Vorarbeiten weltweit1 konnten im Dezember 1947 die amerikanischen Physiker Walter H. Brattain, John Bardeen und William Shockley in den Bell Laboratories den Transistoreffekt demonstrieren. Damit legten sie den Grundstein für die Mikroelektronik als Basistechnologie des Informationszeitalters.

  4. Hippocampal CA1 Ripples as Inhibitory Transients

    PubMed Central

    Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-01-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network. PMID:27093059

  5. Transient reducing greenhouse warming on early Mars

    NASA Astrophysics Data System (ADS)

    Wordsworth, R.; Kalugina, Y.; Lokshtanov, S.; Vigasin, A.; Ehlmann, B.; Head, J.; Sanders, C.; Wang, H.

    2017-01-01

    The evidence for abundant liquid water on early Mars despite the faint young Sun is a long-standing problem in planetary research. Here we present new ab initio spectroscopic and line-by-line climate calculations of the warming potential of reduced atmospheres on early Mars. We show that the strength of both CO2-H2 and CO2-CH4 collision-induced absorption (CIA) has previously been significantly underestimated. Contrary to previous expectations, methane could have acted as a powerful greenhouse gas on early Mars due to CO2-CH4 CIA in the critical 250-500 cm-1 spectral window region. In atmospheres of 0.5 bar CO2 or more, percent levels of H2 or CH4 raise annual mean surface temperatures by tens of degrees, with temperatures reaching 273 K for pressures of 1.25-2 bars and 2-10% of H2 and CH4. Methane and hydrogen produced following aqueous alteration of Mars' crust could have combined with volcanically outgassed CO2 to form transient atmospheres of this composition 4.5-3.5 Ga. Our results also suggest that inhabited exoplanets could retain surface liquid water at significant distances from their host stars.

  6. TRANSIENT FEEDBACK AND ROBUST SIGNALING GRADIENTS

    PubMed Central

    Simonyan, Aghavni; Wan, Frederic Y. M.

    2016-01-01

    Robust development of biological organisms in the presence of genetic and epi-genetic perturbations is important for time spans short relative to evolutionary time. Gradients of receptor bound signaling morphogens are responsible for patterning formation and development. A variety of inhibitors for reducing ectopic signaling activities are known to exist and their specific role in down-regulating the undesirable ectopic activities reasonably well understood. However, how a developing organism manages to adjust inhibition/stimulation in response to genetic and/or environmental changes remains to be uncovered. The need to adjust for ectopic signaling activities requires the presence of one or more feedback mechanisms to stimulate the needed adjustment. As the ultimate effect of many inhibitors (including those of the nonreceptor type) is to reduce the availability of signaling morphogens for binding with signaling receptors, a negative feedback on signaling morphogen synthesis rate based on a root-mean-square measure of the spatial distribution of signaling concentration offers a simple approach to robusness and has been demonstrated to be effective in a proof-of-concept implementation. In this paper, we complement the previous investigation of feedback in steady state by examining the effect of one or more feedback adjustments during the transient phase of the biological development. PMID:27840649

  7. The 100 year DASCH Transient Search

    NASA Astrophysics Data System (ADS)

    Miller, George F.; Grindlay, J. E.; Tang, S.; Los, E.

    2014-01-01

    The Digital Access to a Sky Century at Harvard (DASCH) project is currently digitizing the roughly 500,000 photographic plates maintained by the Harvard College Observatory. The Harvard plate collection covers each point of the sky roughly 500 to 3000 times from 1885 to 1992, with limiting magnitudes ranging from B=14-18 mag and photometric accuracy within ±0.1 mag. Production scanning (up to 400 plates/day) is proceeding in Galactic coordinates from the North Galactic Pole and is currently at roughly 50 degrees galactic latitude. The vastness of these data makes the DASCH project ideal to search for transient behavior. In particular, the large time base of the DASCH collection gives an unprecedented advantage when searching for outbursting systems with recurrence rates of decades or longer. These include recurrent novae, rare WZ Sge Cataclysmic Variables, blazars, X-Ray binaries, and supernovae in the Virgo Supercluster. We report here the discovery of previously unidentified stellar-like objects that underwent abnormally large (Δm=5-9) outbursts discovered with DASCH. We also report the discovery of outbursts from previously quiet AM CVn stars, as well as attempt to characterize their recurrence rates.

  8. Solar activity and explosive transient eruptions

    NASA Astrophysics Data System (ADS)

    Ambastha, Ashok

    2016-07-01

    We discuss active and explosive behavior of the Sun observable in a wide range of wavelengths (or energies) and spatio-temporal scales that are not possible for any other star. On the longer time scales, the most notable form of solar activity is the well known so called 11-year solar activity cycle. On the other hand, at shorter time scales of a few minutes to several hours, spectacular explosive transient events, such as, solar flares, prominence eruptions, and coronal mass ejections (CMEs) occur in the outer layers of solar atmosphere. These solar activity cycle and explosive phenomena influence and disturb the space between the Sun and planets. The state of the interplanetary medium, including planetary and terrestrial surroundings, or "the space weather", and its forecasting has important practical consequences. The reliable forecasting of space weather lies in continuously observing of the Sun. We present an account of the recent developments in our understanding of these phenomena using both space-borne and ground-based solar observations.

  9. Cascade flutter analysis with transient response aerodynamics

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Mahajan, Aparajit J.; Keith, Theo G., Jr.; Stefko, George L.

    1991-01-01

    Two methods for calculating linear frequency domain aerodynamic coefficients from a time marching Full Potential cascade solver are developed and verified. In the first method, the Influence Coefficient, solutions to elemental problems are superposed to obtain the solutions for a cascade in which all blades are vibrating with a constant interblade phase angle. The elemental problem consists of a single blade in the cascade oscillating while the other blades remain stationary. In the second method, the Pulse Response, the response to the transient motion of a blade is used to calculate influence coefficients. This is done by calculating the Fourier Transforms of the blade motion and the response. Both methods are validated by comparison with the Harmonic Oscillation method and give accurate results. The aerodynamic coefficients obtained from these methods are used for frequency domain flutter calculations involving a typical section blade structural model. An eigenvalue problem is solved for each interblade phase angle mode and the eigenvalues are used to determine aeroelastic stability. Flutter calculations are performed for two examples over a range of subsonic Mach numbers.

  10. Three Decades of High Energy Transients

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2012-01-01

    Gamma-Ray Bursts are the most brilliant explosions in space. The first GRB was discovered on 1967, just over 40 years ago. It took several years and multiple generations of space and ground instruments to unravel some of the mysteries of this phenomenon. However, many questions remain open today. I will discuss the history, evolution and current status of the GRB field and its contributions in our understanding of the transient high energy sky. Finally, I will describe how GRBs can be utilized in future missions as tools, to probe the cosmic chemical evolution of the Universe Magnetars are magnetically powered rotating neutron stars with extreme magnetic fields (over 10(exp 14) Gauss). They were discovered in the X- and gamma-rays where they predominantly emit their radiation. Very few sources (roughly 24) have been found since their discovery in 1987. NASA's Fermi Gamma-ray Space Telescope was launched June 11, 2009; since then the Fermi Gamma-ray Burst Monitor (GBM) recorded emission from several magnetar sources. In total, six new sources were discovered between 2008 and 2011, with a synergy between Swift, RXTE, Fermi and the Interplanetary Network (IPN). I will give a short history of magnetars and describe how this, once relatively esoteric field, has emerged as a link between several astrophysical areas including Gamma-Ray Bursts.

  11. Arresting a Transient Receptor Potential (TRP) Channel

    PubMed Central

    Shukla, Arun K.; Kim, Jihee; Ahn, Seungkirl; Xiao, Kunhong; Shenoy, Sudha K.; Liedtke, Wolfgang; Lefkowitz, Robert J.

    2010-01-01

    β-Arrestins, originally discovered to desensitize activated G protein-coupled receptors, (aka seven-transmembrane receptors, 7TMRs) also mediate 7TMR internalization and G protein-independent signaling via these receptors. More recently, several regulatory roles of β-arrestins for atypical 7TMRs and non-7TM receptors have emerged. Here, we uncover an entirely novel regulatory role of β-arrestins in cross-talk between the angiotensin receptor (AT1aR) and a member of the transient receptor potential (TRP) ion channel family, TRPV4. AT1aR and TRPV4 form a constitutive complex in the plasma membrane, and angiotensin stimulation leads to recruitment of β-arrestin 1 to this complex. Surprisingly, angiotensin stimulation results in ubiquitination of TRPV4, a process that requires β-arrestin 1, and subsequently to internalization and functional down-regulation of TRPV4. β-Arrestin 1 interacts with, and acts as an adaptor for AIP4, an E3 ubiquitin ligase responsible for TRPV4 ubiquitination. Thus, our data provide the first evidence of a functional link between β-arrestins and TRPV4 and uncovers an entirely novel mechanism to maintain appropriate intracellular Ca2+ concentration to avoid excessive Ca2+ signaling. PMID:20650893

  12. Transient particle acceleration associated with solar flares.

    PubMed

    Chupp, E L

    1990-10-12

    Understanding how individual charged particles can be accelerated to extreme energies (10(20) electron volts), remains a foremost problem in astrophysics. Within our solar system, the active sun is capable of producing, on a short time scale, ions with energies higher than 25 gigaelectron volts. Satellite and ground-based observation over the past 30 years have greatly increased our knowledge of the properties of transient bursts of energetic particles emitted from the sun in association with solar flares, but a real understanding of the solar flare particle acceleration process requires greatly refined experimental data. On the practical side, it is also imperative that this problem be solved if man is to venture, for long periods of time, beyond the protective umbrella of Earth's magnetic field, which excludes much of the biologically damaging solar energetic particles. It is only through an understanding of the basic acceleration problem that we can expect to be able to predict the occurrence of a solar flare with lethal solar radiations. For our knowledge of these effects to advance, a new space mission dedicated to studying the high-energy aspects of solar flares at high spatial and energy resolution will be required.

  13. High-energy emission from transients.

    PubMed

    Hinton, J A; Starling, R L C

    2013-06-13

    Cosmic explosions dissipate energy into their surroundings on a very wide range of time scales: producing shock waves and associated particle acceleration. The historical culprits for the acceleration of the bulk of Galactic cosmic rays are supernova remnants: explosions on approximately 10(4) year time scales. Increasingly, however, time-variable emission points to rapid and efficient particle acceleration in a range of different astrophysical systems. Gamma-ray bursts have the shortest time scales, with inferred bulk Lorentz factors of approximately 1000 and photons emitted beyond 100 GeV, but active galaxies, pulsar wind nebulae and colliding stellar winds are all now associated with time-variable emission at approximately teraelectron volt energies. Cosmic photons and neutrinos at these energies offer a powerful probe of the underlying physical mechanisms of cosmic explosions, and a tool for exploring fundamental physics with these systems. Here, we discuss the motivations for high-energy observations of transients, the current experimental situation, and the prospects for the next decade, with particular reference to the major next-generation high-energy observatory, the Cherenkov Telescope Array.

  14. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert

    1998-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one 'snap-shot' of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: Shocks; Vortex ores; Regions of Recirculation; Boundary Layers; Wakes.

  15. Large Angle Transient Dynamics (LATDYN) user's manual

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. Louis; Chang, Che-Wei; Powell, Michael G.; Wu, Shih-Chin; Bingel, Bradford D.; Theophilos, Paula M.

    1991-01-01

    A computer code for modeling the large angle transient dynamics (LATDYN) of structures was developed to investigate techniques for analyzing flexible deformation and control/structure interaction problems associated with large angular motions of spacecraft. This type of analysis is beyond the routine capability of conventional analytical tools without simplifying assumptions. In some instances, the motion may be sufficiently slow and the spacecraft (or component) sufficiently rigid to simplify analyses of dynamics and controls by making pseudo-static and/or rigid body assumptions. The LATDYN introduces a new approach to the problem by combining finite element structural analysis, multi-body dynamics, and control system analysis in a single tool. It includes a type of finite element that can deform and rotate through large angles at the same time, and which can be connected to other finite elements either rigidly or through mechanical joints. The LATDYN also provides symbolic capabilities for modeling control systems which are interfaced directly with the finite element structural model. Thus, the nonlinear equations representing the structural model are integrated along with the equations representing sensors, processing, and controls as a coupled system.

  16. Analysis of electrical transients created by lightning

    NASA Technical Reports Server (NTRS)

    Nanevicz, J. E.; Vance, E. F.

    1980-01-01

    A series of flight tests was conducted using a specially-instrumented NASA Learjet to study the electrical transients created on an aircraft by nearby lightning. The instrumentation included provisions for the time-domain and frequency-domain recording of the electrical signals induced in sensors located both on the exterior and on the interior of the aircraft. The design and calibration of the sensors and associated measuring systems is described together with the results of the flight test measurements. The results indicate that the concept of providing instrumentation to follow the lightning signal from propagation field, to aircraft skin current, to current on interior wiring is basically sound. The results of the measurement indicate that the high frequency signals associated with lightning stroke precursor activity are important in generating electromagnetic noise on the interior of the aircraft. Indeed, the signals produced by the precursors are often of higher amplitude and of longer duration that the pulse produced by the main return stroke.

  17. Transient thermal analysis of micromachined silicon bridge

    NASA Astrophysics Data System (ADS)

    Yuasa, Hiroyasu; Ohya, Seishiro; Karasawa, Shiro; Kodato, Setsuo; Akimoto, Kenji

    1996-09-01

    We investigate the transient thermal response of micromachined silicon microbridges. The silicon microbridge has a large potential for sensors relating to heat because silicon has large thermal conductivity. The silicon microbridge is stable in heat cycle compared with the other hetero-structures. The silicon process has an advantage of mass production and good controllability. The silicon microbridge is abruptly heated by its Joule's heat when a voltage pulse is applied. The measured time constant was less than 1 ms because the heat capacity of the microbridge is small. A heavily doped silicon layer which is made by ion implantation works as stopping layer for anisotropic etching process. Furthermore the dependence of resistance on temperature is metallic such that the drive current is automatically controlled with negative feedback. We could easily control the temperature of silicon microbridge by electric signal up to the frequency range of 1 kHz. The temperature modulation was more than 700 degree(s)C at 100 Hz. The microbridge is one of the fastest heater driven by Joule's heat because of the small heat capacity and the large thermal conductivity of silicon.

  18. Transient pulsed radio emission from a magnetar

    NASA Astrophysics Data System (ADS)

    Camilo, Fernando; Ransom, Scott M.; Halpern, Jules P.; Reynolds, John; Helfand, David J.; Zimmerman, Neil; Sarkissian, John

    2006-08-01

    Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >1014 G, according to the `magnetar' model. The radio pulsations that have been observed from more than 1,700 neutron stars with weaker magnetic fields have never been detected from any of the dozen known magnetars. The X-ray pulsar XTE J1810 - 197 was revealed (in 2003) as the first AXP with transient emission when its luminosity increased 100-fold from the quiescent level; a coincident radio source of unknown origin was detected one year later. Here we show that XTE J1810 - 197 emits bright, narrow, highly linearly polarized radio pulses, observed at every rotation, thereby establishing that magnetars can be radio pulsars. There is no evidence of radio emission before the 2003 X-ray outburst (unlike ordinary pulsars, which emit radio pulses all the time), and the flux varies from day to day. The flux at all radio frequencies is approximately equal-and at >20GHz XTE J1810 - 197 is currently the brightest neutron star known. These observations link magnetars to ordinary radio pulsars, rule out alternative accretion models for AXPs, and provide a new window into the coronae of magnetars.

  19. Transient dynamics capability at Sandia National Laboratories

    NASA Technical Reports Server (NTRS)

    Attaway, Steven W.; Biffle, Johnny H.; Sjaardema, G. D.; Heinstein, M. W.; Schoof, L. A.

    1993-01-01

    A brief overview of the transient dynamics capabilities at Sandia National Laboratories, with an emphasis on recent new developments and current research is presented. In addition, the Sandia National Laboratories (SNL) Engineering Analysis Code Access System (SEACAS), which is a collection of structural and thermal codes and utilities used by analysts at SNL, is described. The SEACAS system includes pre- and post-processing codes, analysis codes, database translation codes, support libraries, Unix shell scripts for execution, and an installation system. SEACAS is used at SNL on a daily basis as a production, research, and development system for the engineering analysts and code developers. Over the past year, approximately 190 days of CPU time were used by SEACAS codes on jobs running from a few seconds up to two and one-half days of CPU time. SEACAS is running on several different systems at SNL including Cray Unicos, Hewlett Packard PH-UX, Digital Equipment Ultrix, and Sun SunOS. An overview of SEACAS, including a short description of the codes in the system, are presented. Abstracts and references for the codes are listed at the end of the report.

  20. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert; Lovely, David

    1999-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snap-shot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: (1) Shocks, (2) Vortex cores, (3) Regions of recirculation, (4) Boundary layers, (5) Wakes. Three papers and an initial specification for the (The Fluid eXtraction tool kit) FX Programmer's guide were included. The papers, submitted to the AIAA Computational Fluid Dynamics Conference, are entitled : (1) Using Residence Time for the Extraction of Recirculation Regions, (2) Shock Detection from Computational Fluid Dynamics results and (3) On the Velocity Gradient Tensor and Fluid Feature Extraction.

  1. PoET: Polarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    McConnell, Mark; Barthelmy, Scott; Hill, Joanne

    2008-01-01

    This presentation focuses on PoET (Polarimeters for Energetic Transients): a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The PoET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. PoET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  2. Transient Receptor Potential Channels in the Vasculature

    PubMed Central

    Earley, Scott; Brayden, Joseph E.

    2015-01-01

    The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca2+ levels or subcellular Ca2+ signaling events. In addition to directly mediating Ca2+ entry, TRP channels influence intracellular Ca2+ dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions. PMID:25834234

  3. Transient nuclear Prospero induces neural progenitor quiescence

    PubMed Central

    Lai, Sen-Lin; Doe, Chris Q

    2014-01-01

    Stem cells can self-renew, differentiate, or enter quiescence. Understanding how stem cells switch between these states is highly relevant for stem cell-based therapeutics. Drosophila neural progenitors (neuroblasts) have been an excellent model for studying self-renewal and differentiation, but quiescence remains poorly understood. In this study, we show that when neuroblasts enter quiescence, the differentiation factor Prospero is transiently detected in the neuroblast nucleus, followed by the establishment of a unique molecular profile lacking most progenitor and differentiation markers. The pulse of low level nuclear Prospero precedes entry into neuroblast quiescence even when the timing of quiescence is advanced or delayed by changing temporal identity factors. Furthermore, loss of Prospero prevents entry into quiescence, whereas a pulse of low level nuclear Prospero can drive proliferating larval neuroblasts into quiescence. We propose that Prospero levels distinguish three progenitor fates: absent for self-renewal, low for quiescence, and high for differentiation. DOI: http://dx.doi.org/10.7554/eLife.03363.001 PMID:25354199

  4. Transient evoked otoacoustic emissions in the elderly.

    PubMed

    Stenklev, Niels Christian; Laukli, Einar

    2003-04-01

    The purpose of this study was to analyse the changes in transient evoked otoacoustic emissions (TEOAEs) with age. We studied 232 subjects above 60 years of age with a battery of audiological tests, including TEOAEs Our criterion for the presence of TEOAEs was based on a cut-off at overall wave reproducibility 55% or overall response level 4 dB SPL. The prevalence of TEOAEs in left ears was 55.6%. No TEOAEs were found in subjects with a pure-tone average (PTA) above 40 dB HL. In the subgroup with TEOAEs, a significant decrease in overall wave reproducibility with age was found. We compared 45 normal-hearing elderly subjects with TEOAEs with a control group of 20 normal-hearing young adults The elderly had significantly lower mean overall response levels and mean overall wave reproducibility. Average hearing level was significantly higher in the elderly than in controls We conclude that the prevalence of TEOAEs decreases with age, and that the overall response level and overall reproducibility decrease with age. This decrease may not be seen in isolation from the increase in hearing threshold level.

  5. Extreme Transients in the High Energy Universe

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2013-01-01

    The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

  6. Transient Mixing Driven by Buoyancy Flows

    NASA Technical Reports Server (NTRS)

    Duval, W. M. B.; Batur, C.; Zhong, H.

    2002-01-01

    Mixing driven by buoyancy-induced flows is of particular interest to microgravity processes, as the body force that governs the intensity of flow fields can be directly controlled. We consider a model experimental system to explore the dynamics of mixing which employs two miscible liquids inside a cavity separated initially by a divider. The two liquids are oriented vertically inside a rectangular cavity with constant width and height, and varying depths to span the range of a Hele-Shaw cell to a 3-D configuration. The two miscible liquids can be sufficiently diluted and died, for example water and deuterium oxide, such that a distinct interface exists across the divider. The transient mixing characteristic of the two fluids is addressed by following the Lagrangian history of the interface for various aspect ratios in the z-plane (depth variation) as well as a range of pulling velocities of the divider. The mixing characteristics of the two fluids are quantified from measurement of the length stretch of the interface and its flow field using respectively image processing techniques and Particle Imaging Velocimetry. Scaling analysis shows that the length stretch depends on four governing parameters, namely the Grashof number (Gr), Schmidt number (Sc), aspect ratio (Ar), and Reynolds number (Re). Variation of the Schmidt number is taken into account through thermophysical property variation. Thus our problem reduces to a codimension three bifurcation in parametric space for Gr, Ar, and Re.

  7. Clusters of mutations from transient hypermutability.

    PubMed

    Drake, John W; Bebenek, Anna; Kissling, Grace E; Peddada, Shyamal

    2005-09-06

    Collections of mutants usually contain more mutants bearing multiple mutations than expected from the mutant frequency and a random distribution of mutations. This excess is seen in a variety of organisms and also after DNA synthesis in vitro. The excess is unlikely to originate in mutator mutants but rather from transient hypermutability resulting from a perturbation of one of the many transactions that maintain genetic fidelity. The multiple mutations are sometimes clustered and sometimes randomly distributed. We model some spectra as populations comprising a majority with a low mutation frequency and a minority with a high mutation frequency. In the case of mutants produced in vitro by a bacteriophage RB69 mutator DNA polymerase, mutants with two mutations are in approximately 10-fold excess and mutants with three mutations are in even greater excess. However, phenotypically undetectable mutations seen only as hitchhikers with detectable mutations are approximately 5-fold more frequent than mutants bearing detectable mutations, indicating that they arose in a subpopulation with a higher mutation frequency. Excess multiple mutations may contribute critically to carcinogenesis and to adaptive mutation, including the adaptations of pathogens as they move from host to host. In the case of the rapidly mutating riboviruses, the viral population appears to be composed of a majority with a mutation frequency substantially lower than the average and a minority with a huge mutational load.

  8. Transient pulsed radio emission from a magnetar.

    PubMed

    Camilo, Fernando; Ransom, Scott M; Halpern, Jules P; Reynolds, John; Helfand, David J; Zimmerman, Neil; Sarkissian, John

    2006-08-24

    Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >10(14) G, according to the 'magnetar' model. The radio pulsations that have been observed from more than 1,700 neutron stars with weaker magnetic fields have never been detected from any of the dozen known magnetars. The X-ray pulsar XTE J1810-197 was revealed (in 2003) as the first AXP with transient emission when its luminosity increased 100-fold from the quiescent level; a coincident radio source of unknown origin was detected one year later. Here we show that XTE J1810-197 emits bright, narrow, highly linearly polarized radio pulses, observed at every rotation, thereby establishing that magnetars can be radio pulsars. There is no evidence of radio emission before the 2003 X-ray outburst (unlike ordinary pulsars, which emit radio pulses all the time), and the flux varies from day to day. The flux at all radio frequencies is approximately equal--and at >20 GHz XTE J1810-197 is currently the brightest neutron star known. These observations link magnetars to ordinary radio pulsars, rule out alternative accretion models for AXPs, and provide a new window into the coronae of magnetars.

  9. Hippocampal CA1 Ripples as Inhibitory Transients.

    PubMed

    Malerba, Paola; Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-04-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  10. Transient translational quiescence in primordial germ cells.

    PubMed

    Oulhen, Nathalie; Swartz, S Zachary; Laird, Jessica; Mascaro, Alexandra; Wessel, Gary

    2017-02-24

    Stem cells in animals often exhibit a slow cell cycle and/or low transcriptional activity referred to as quiescence. Here we report that the translational activity in the primordial germ cells (PGCs) of the sea urchin embryo (Strongylocentrotus purpuratus) is quiescent. We measured new protein synthesis with O-propargyl-puromycin, and L-homopropargylglycine, Click-iT technologies and determined that these cells synthesize protein at only 6% the level of their adjacent somatic cells. Knock-down of translation of the RNA-binding protein Nanos2 by morpholino anti-sense oligonucleotides, or knock-out of the Nanos2 gene by CRISPR/Cas9 resulted in a significant, but partial increase (47%) in general translation specifically in the PGCs. We found that the mRNA of the translation factor eEF1A is excluded from the PGCs in a Nanos2-dependent manner, a consequence of a Nanos/Pumilio response element (PRE) in its 3'UTR. In addition to eEF1A, the cytoplasmic pH of the PGCs appears to repress translation and simply increasing the pH also significantly restores translation selectively in the PGCs. We conclude that the PGCs of this sea urchin institute parallel pathways to quiesce translation thoroughly but transiently.

  11. [Naturheilkunde und Komplementärmedizin in medizinischen Leitlinien - können europäische Normen Leitlinien für Naturheilkunde und Komplementärmedizin verdrängen?].

    PubMed

    Jütte, Robert

    2016-01-01

    Leitlinien machen in der Komplementärmedizin, wie das Beispiel der Naturheilkunde zeigt, durchaus Sinn. Sie ergänzen zum Wohle des Patienten und zur besseren Orientierung des Therapeuten die bislang, auch auf europäischer Ebene, bereits bestehenden Leitlinien, die ständig weiterentwickelt werden. Diese Ergänzung ist dringend notwendig, weil die meisten der vorliegenden Leitlinien einzelner Fachgesellschaften die Forschungsergebnisse der Komplementärmedizin, die zum Teil beachtlich und auch evidenzbasiert sind, zum Nachteil des Patienten ignorieren. Es ist bedauerlich, dass einige Richtungen der Komplementärmedizin jedoch meinen, dass eine europäische Norm, wie sie beispielsweise Osteopathen und Homöopathen mithilfe des europäischen Normungsinstituts (CEN) durchzusetzen hoffen, sie in ihrem Kampf um Anerkennung weiterbringen wird. Der Patient, der auf eine individuelle und bestmögliche Behandlung wert legt, wird jedenfalls davon nicht profitieren.

  12. Capture-recapture survival models taking account of transients

    USGS Publications Warehouse

    Pradel, R.; Hines, J.E.; Lebreton, J.D.; Nichols, J.D.

    1997-01-01

    The presence of transient animals, common enough in natural populations, invalidates the estimation of survival by traditional capture- recapture (CR) models designed for the study of residents only. Also, the study of transit is interesting in itself. We thus develop here a class of CR models to describe the presence of transients. In order to assess the merits of this approach we examme the bias of the traditional survival estimators in the presence of transients in relation to the power of different tests for detecting transients. We also compare the relative efficiency of an ad hoc approach to dealing with transients that leaves out the first observation of each animal. We then study a real example using lazuli bunting (Passerina amoena) and, in conclusion, discuss the design of an experiment aiming at the estimation of transience. In practice, the presence of transients is easily detected whenever the risk of bias is high. The ad hoc approach, which yields unbiased estimates for residents only, is satisfactory in a time-dependent context but poorly efficient when parameters are constant. The example shows that intermediate situations between strict 'residence' and strict 'transience' may exist in certain studies. Yet, most of the time, if the study design takes into account the expected length of stay of a transient, it should be possible to efficiently separate the two categories of animals.

  13. Transient response characteristics in a biomolecular integral controller.

    PubMed

    Sen, Shaunak

    2016-04-01

    The cellular behaviour of perfect adaptation is achieved through the use of an integral control element in the underlying biomolecular circuit. It is generally unclear how integral action affects the important aspect of transient response in these biomolecular systems, especially in light of the fact that it typically deteriorates the transient response in engineering contexts. To address this issue, the authors investigated the transient response in a computational model of a simple biomolecular integral control system involved in bacterial signalling. They find that the transient response can actually speed up as the integral gain parameter increases. On further analysis, they find that the underlying dynamics are composed of slow and fast modes and the speed-up of the transient response is because of the speed-up of the slow-mode dynamics. Finally, they note how an increase in the integral gain parameter also leads to a decrease in the amplitude of the transient response, consistent with the overall improvement in the transient response. These results should be useful in understanding the overall effect of integral action on system dynamics, particularly for biomolecular systems.

  14. Walker circulation in a transient climate

    NASA Astrophysics Data System (ADS)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  15. Air Heating Associated with Transient Luminous Events

    NASA Astrophysics Data System (ADS)

    Riousset, J. A.; Pasko, V. P.; Bourdon, A.

    2009-12-01

    The understanding of ambient gas heating processes initiated by needle-shaped filaments of ionization, called streamers, embedded in originally cold air (near room temperature) represents a long standing problem, which is of interest for studies of long laboratory sparks and natural lightning discharges [e.g., Gallimberti et al., C. R. Physique, 3, 1335, 2002]. The observed phenomenology of a subset of the recently observed transient luminous events in the middle atmosphere, which originate from thundercloud tops [e.g, Wescott et al., JGR, 106, 21549, 2001; Pasko et al., Nature, 416, 152, 2002; Su et al., Nature, 423, 974, 2003; Krehbiel et al., Nature Geoscience, 1, 233, 2008; Cummer et al., Nature Geoscience, 2, 617, 2009, Riousset et al., JGR, 10.1029/2009JA014286, 2009, in press], indicate that these events may be related to conventional lightning leader processes and therefore are associated with significant heating of the air in the regions of atmosphere through which they propagate [Pasko and George, JGR, 107, 1458, 2002]. Many of the small scale features observed in sprites at higher altitudes [e.g., Stenbaek-Nielsen et al., GRL, 104, L11105, 2007, and references therein] can be interpreted in terms of corona streamers, which, after appropriate scaling with air density, are fully analogous to those, which initiate spark discharges in relatively short (several cm) gaps at near ground pressure [Liu et al., JGR, 114, A00E03, 2009, and references therein] and which constitute building blocks of streamer zones of conventional lightning leaders in long gaps [Gallimberti et al., 2002]. The recent reports of infrasound bursts originating from 60-80 km altitudes in sprites, with durations consistent with the optical widths of the sprites [e.g., Farges, in Lightning: Principles, Instruments and Applications, p. 417, Betz et al., (eds.), Springer, 2009], provide an additional motivation for studies of the heating of the ambient air and associated chemical effects

  16. Acute transient hemiparesis induced by lightning strike.

    PubMed

    Rahmani, Seyed Hesam; Faridaalaee, Gholamreza; Jahangard, Samira

    2015-07-01

    According to data from the National Oceanic and Atmospheric Administration,in the years from 1959 to 1994, lightning was responsible for more than 3000 deaths and nearly 10,000 casualties. The most important characteristic features of lightning injuries are multisystem involvement and widely variable severity. Lightning strikes are primarily a neurologic injury that affects all 3 components of the nervous system: central, autonomic,and peripheral. Neurologic complications of lightning strikes vary from transient benign symptoms to permanent disability. Many patients experience a temporary paralysis called keraunoparalysis. Here we reported a 22-year-old mountaineer man with complaining of left sided hemiparesis after being hit by a lightning strike in the mountain 3 hours ago. There was no loss of consciousness at hitting time. On arrival the patient was alert, awake and hemodynamically stable. In neurologic examination cranial nerves were intact, left sided upper and lower extremity muscle force was I/V with a combination of complete sensory loss, and right-sided muscle force and sensory examination were normal. There is not any evidence of significant vascular impairment in the affected extremities. Brain MRI and CT scan and cervical MRI were normal. During 2 days of admission, with intravenous hydration, heparin 5000 unit SC q12hr and physical therapy of the affected limbs, motor and sensory function improved and was normal except mild paresthesia. He was discharged 1 day later for outpatient follow up while vitamin B1 100mg orally was prescribed.Paresthesia improved after 3 days without further sequels.

  17. The SCEC geodetic transient detection validation exercise

    USGS Publications Warehouse

    Lohman, Rowena B.; Murray, Jessica R.

    2013-01-01

    Over the past decade the number and size of continuously operating Global Positioning System (GPS) networks has grown substantially worldwide. A steadily increasing volume of freely available GPS measurements, combined with the application of new approaches for mining these data for signals of interest, has led to the identification of a large and diverse collection of time‐varying Earth processes. One phenomenon that has been observed is transient fault slip (also termed slow slip events or silent earthquakes) occurring over time spans of days to years (e.g., Linde et al., 1996; Hirose et al., 1999; Dragert et al., 2001; Miller et al., 2002; Kostoglodov et al., 2003; Douglas et al., 2005; Shelly et al., 2006; Ide et al., 2007; Lohman and McGuire, 2007; Schwartz and Rokosky, 2007; Szeliga et al., 2008). Such events have been widely observed in subduction zones but are also found in other tectonic settings (Linde et al., 1996; Cervelli et al., 2002; Murray and Segall, 2005; Lohman and McGuire, 2007; Montgomery‐Brown et al., 2009; Shelly, 2010; and references therein). Although retrospective study of slow‐slip events using geodetic observations is driving the formulation of new models for fault‐zone behavior and constitutive laws (e.g., Lapusta et al., 2000; Liu and Rice, 2007; Lapusta and Liu, 2009; Segall and Bradley, 2012a), much of the research on near‐real‐time detection and characterization of anomalous behaviors along fault zones has focused solely on the use of seismic tremor (e.g., Rogers and Dragert, 2003; Shelly et al., 2006; Ito et al., 2007).

  18. Recharge estimation for transient ground water modeling.

    PubMed

    Jyrkama, Mikko I; Sykes, Jon F; Normani, Stefano D

    2002-01-01

    Reliable ground water models require both an accurate physical representation of the system and appropriate boundary conditions. While physical attributes are generally considered static, boundary conditions, such as ground water recharge rates, can be highly variable in both space and time. A practical methodology incorporating the hydrologic model HELP3 in conjunction with a geographic information system was developed to generate a physically based and highly detailed recharge boundary condition for ground water modeling. The approach uses daily precipitation and temperature records in addition to land use/land cover and soils data. The importance of the method in transient ground water modeling is demonstrated by applying it to a MODFLOW modeling study in New Jersey. In addition to improved model calibration, the results from the study clearly indicate the importance of using a physically based and highly detailed recharge boundary condition in ground water quality modeling, where the detailed knowledge of the evolution of the ground water flowpaths is imperative. The simulated water table is within 0.5 m of the observed values using the method, while the water levels can differ by as much as 2 m using uniform recharge conditions. The results also show that the combination of temperature and precipitation plays an important role in the amount and timing of recharge in cooler climates. A sensitivity analysis further reveals that increasing the leaf area index, the evaporative zone depth, or the curve number in the model will result in decreased recharge rates over time, with the curve number having the greatest impact.

  19. Transient gene expression in electroporated Solanum protoplasts.

    PubMed

    Jones, H; Ooms, G; Jones, M G

    1989-11-01

    Electroporation was used to evaluate parameters important in transient gene expression in potato protoplasts. The protoplasts were from leaves of wild potato Solanum brevidens, and from leaves, tubers and suspension cells of cultivated Solanum tuberosum cv. Désirée. Reporter enzyme activity, chloramphenicol acetyl transferase (CAT) under the control of the cauliflower mosaic virus (CaMV) 35S promoter, depended on the field strength and the pulse duration used for electroporation. Using field pulses of 85 ms duration, the optimum field strengths for maximum CAT activity were: S. brevidens mesophyll protoplasts--250 V/cm; Désirée mesophyll protoplasts--225 V/cm; Désirée suspension culture protoplasts--225 V/cm; and Désirée tuber protoplasts--150 V/cm. The optimum field strengths correlated inversely with the size of the protoplasts electroporated; this is consistent with biophysical theory. In time courses, maximum CAT activity (in Désirée mesophyll protoplasts) occurred 36-48 h after electroporation. Examination at optimised conditions of a chimaeric gene consisting of a class II patatin promoter linked to the beta-glucuronidase (gus) gene, showed expression (at DNA concentrations between 0-10 pmol/ml) comparable to the CaMV 35S promoter in both tuber and mesophyll protoplasts. At higher DNA concentrations (20-30 pmol/ml) the patatin promoter directed 4-5 times higher levels of gus expression. Implications and potential contributions towards studying gene expression, in particular of homologous genes in potato, are discussed.

  20. Spatial fluctuations in transient creep deformation

    NASA Astrophysics Data System (ADS)

    Laurson, Lasse; Rosti, Jari; Koivisto, Juha; Miksic, Amandine; Alava, Mikko J.

    2011-07-01

    We study the spatial fluctuations of transient creep deformation of materials as a function of time, both by digital image correlation (DIC) measurements of paper samples and by numerical simulations of a crystal plasticity or discrete dislocation dynamics model. This model has a jamming or yielding phase transition, around which power law or Andrade creep is found. During primary creep, the relative strength of the strain rate fluctuations increases with time in both cases—the spatially averaged creep rate obeys the Andrade law epsilont ~ t - 0.7, while the time dependence of the spatial fluctuations of the local creep rates is given by Δepsilont ~ t - 0.5. A similar scaling for the fluctuations is found in the logarithmic creep regime that is typically observed for lower applied stresses. We review briefly some classical theories of Andrade creep from the point of view of such spatial fluctuations. We consider these phenomenological, time-dependent creep laws in terms of a description based on a non-equilibrium phase transition separating evolving and frozen states of the system when the externally applied load is varied. Such an interpretation is discussed further by the data collapse of the local deformations in the spirit of absorbing state/depinning phase transitions, as well as deformation-deformation correlations and the width of the cumulative strain distributions. The results are also compared with the order parameter fluctuations observed close to the depinning transition of the 2d linear interface model or the quenched Edwards-Wilkinson equation.

  1. Nonlinear damping identification from transient data

    NASA Astrophysics Data System (ADS)

    Smith, Clifford B.; Wereley, Norman M.

    1999-06-01

    To study new damping augmentation methods for helicopter rotor systems, accurate and reliable nonlinear damping identification techniques are needed. For example, current studies on applications of magnetorheological (MR) dampers for rotor stability augmentation suggest that a strong Coulomb damping characteristic will be manifested as the field applied to the MR fluid is maximized. Therefore, in this work, a single degree of freedom (SDOF) system having either nonlinear Coulomb or quadratic damping is considered. This paper evaluates three analyses for identifying damping from transient test data; an FFT-based moving block analysis, an analysis based on a periodic Fourier series decomposition, and a Hilbert transform based technique. Analytical studies are used to determine the effects of block length, noise, and error in identified modal frequency on the accuracy of the identified damping level. The FFT-based moving block has unacceptable performance for systems with nonlinear damping. These problems were remedied in the Fourier series based analysis and acceptable performance is obtained for nonlinear damping identification from both this technique and the Hilbert transform based method. To more closely simulate a helicopter rotor system test, these techniques were then applied to a signal composed of two closely spaced modes. This data was developed to simulate a response containing the first lag and 1/rev modes. The primary mode of interest (simulated lag mode) had either Coulomb or quadratic damping, and the close mode (1/rev) was either undamped or had a specified viscous damping level. A comprehensive evaluation of the effects of close mode amplitude, frequency, and damping level was performed. A classifier was also developed to identify the dominant damping mechanism in a signal of 'unknown' composition. This classifier is based on the LMS error of a fit of the analytical envelope expression to the experimentally identified envelope signal. In most

  2. Remote Sensing of Transient Luminous Events

    NASA Astrophysics Data System (ADS)

    Fullekrug, M.; Whitley, T.; Mezentsev, A.; van der Velde, O. A.; Soula, S.; Chanrion, O.; Neubert, T.; Roussel-Dupre, R. A.

    2012-12-01

    Transient Luminous Events are investigated by remote sensing with several networks of radio receivers. Spectacular sprites are detected by use of their characteristic signatures following the continuing current of their parent positive cloud to ground lightning discharges which are recorded with a global network of four radio receivers operating at a frequency range from ~1-1000 Hz. This novel data set reveals a new class of sprites, where the intensity of the sprite exceeds the intensity of the parent lightning discharge, presumably as a result of continued horizontal lightning activity. These Mega-Sprites occur mainly during night-time and with a likelihood of less than ~10% during day-time. The spectra of Mega-Sprites are inferred from the electromagnetic recordings. Sprites with more moderate luminousity are occaisonally associated with weak electromagnetic signatures in the frequency range from ~40-400 kHz. It is shown that one of these signatures coincides with an extremely weak rebrightening of an ongoing sprite. The rebrightening exhibits an emission of ~50 photons over ~1 ms as measured with a fast scanning photomultiplier tube. This optical signature may result from relativisitc electrons in the mesosphere in agreement with corresponding model calculations. To test this hypothesis in more detail, a network of ten wideband digital radio receivers is deployed in southern France to operate as a small scale interferometer. The first results are obatined at a frequency of 100 kHz and show the bearings to radio transmitters and lightning discharges from distant thunderstorms and reveal an anisotropic wave propagation velocity.

  3. Secondary porosity in a transient vadose zone

    SciTech Connect

    Frederick, W.T.; Grasso, T.X. Jr. )

    1993-03-01

    The Western New York Nuclear Service Center is the site of low and high level radioactive waster buried in a series of trenches excavated in a 28 m thick, Lavery-age silty clay diamicton that exhibits a 6 meter thick transient vadoes zone where exposed at the surface. Hydrostratigraphy of this till includes a 0.25 m thick poorly developed macroporous soil, a 3.5 m thick weathered zone of densely spaced and randomly orientated horizontal and vertical fractures, a 2 m thick unweathered zone of intermittently spaced fractures exhibiting east-west orientations, and a massive 23 m thick unweathered till zone that exhibits isolated, east-west orientated fractures. Bulk hydraulic conductivity of this active flow zone decreases with depth from 10[sup [minus]5] to 10[sup [minus]8] cm/s. The specific discharge of vertically flowing groundwater in the massive till zone is 1.25 cm/yr. A water surplus in the recharge season saturates the fractured zone to grade with up to 7.37 cm/yr of net infiltration. Tritium and radionuclides from the waste trenches and surrounding soil matrix hydrodynamically disperse into the field-saturated fracture network that contains meteoric recharge water. A soil moisture deficit in discharge season produces a vadose zone of widened fractures that via capillarity enhances the diffusion of contaminants into the soil matrix. These enlarged connecting conduits laterally channel the excess infiltration from the recharge season and diffused contaminants to local lowlands and incised streams that truncate the unweathered till. The current vadose and phreatic zone flow study will be used in numeric simulations that will delineate the areal extend and temporal duration of these seepage faces and the time frame of possible surfaces water contamination.

  4. Searching for Strain Transients in PBO data

    NASA Astrophysics Data System (ADS)

    Wei, M.; McGuire, J. J.; Richardson, E.; Kraft, R. L.; Hardwig, M. D.

    2011-12-01

    We applied a recently developed strain anomaly detector, the Network Stain Filter [Ohtani et al., 2010], to the continuous GPS datasets from the PBO in Alaska and Salton Trough. The strategy of the filter is to find spatially and temporally coherent signals by processing data from the entire network simultaneously. Compared to previous Network Inversion Filter [Segall and Matthews, 1997], the new detector does not require the knowledge of potential sources, which can be either unknown and/or very numerous in a large tectonically active area. At Alaska, we find a strain anomaly between Kodiak Island and Kenai Peninsula that began in early 2010. There are earthquakes that are likely related to the strain anomaly. The physical interpretation of the strain anomaly is still in progress. The secular motion since 2006 that PBO recorded is consistent with a model that consist of two locked patches on Kodiak Island and Kenai Peninsula and a creeping patch near Cook Inlet as determined earlier by Zweck et al. [2002]. Seasonal signals dominate in the data and are highly correlated between stations in the horizontal components. The reason for this correlation in seasonal term azimuths between stations is not clear. At Salton Trough, the post-seismic deformation of the 2010 Mw 7.2 El Mayor Earthquake dominates the transient signals. The maximum post-seismic slip recorded by the GPS is 23 mm during 1.5 years after the earthquake (Site ID P494). Additionally, we are exploring using InSAR data as a complimentary method for detecting strain anomaly in areas with shallow sources, such as in the Salton Trough. A creep event on the Superstition Hills Fault in October 2006 has been observed by InSAR but missed by nearby GPS stations due to low amplitude at the location [Wei et al., 2009].

  5. Transient burning of a convective fuel droplet

    SciTech Connect

    Wu, Guang; Sirignano, William A.

    2010-05-15

    The transient burning of an n-octane fuel droplet in a hot gas stream at 20 atmosphere pressure is numerically studied, with considerations of droplet regression, deceleration due to the drag of the droplet, internal circulation inside the droplet, variable properties, non-uniform surface temperature, and the effect of surface tension. An initial envelope flame is found to remain envelope in time, and an initial wake flame is always transitioned into an envelope flame at a later time, with the normalized transition delay controlled by the initial Reynolds number and the initial Damkohler number. The initial flame shape is primarily determined by the initial Damkohler number, which has a critical value of Da{sub 0}=1.02. The burning rates are modified by the transition, and are influenced by the intensity of forced convection which is determined by initial Reynolds number. The influence of surface tension is also studied as the surface temperature is non-uniform. Surface tension affects the liquid motion at the droplet surface significantly and affects the change of surface temperature and burning rate modestly. The influence of surface tension generally increases with increasing initial Reynolds number within the range without droplet breakup. We also studied cases with constant relative velocity between the air stream and the droplet. The results show that in these cases the initial envelope flame still remains envelope, but the evolution from an initial wake flame to an envelope flame is inhibited. Validation of our analysis is made by comparing with a published porous-sphere experiment Raghavan et al. (2005) which used methanol fuel. (author)

  6. Transient response of premixed methane flames

    SciTech Connect

    Vagelopoulos, Christina M.; Frank, Jonathan H.

    2006-08-15

    The response of premixed methane-air flames to transient strain and local variations in equivalence ratio is studied during isolated interactions between a line-vortex pair and a V-flame. The temporal evolution of OH and CH is measured with planar laser-induced fluorescence for N{sub 2}-diluted flames with equivalence ratios ranging from 0.8 to 1.2. One-dimensional laminar flame calculations are used to simulate the flame response to unsteady strain and variations in reactant composition. When the reactant composition of the vortex pair and the V-flame are identical, the measurements and predictions show that the peak mole fractions of OH and CH decay monotonically in lean, stoichiometric, and rich flames. We also investigate the effects of a vortex pair with a leaner composition than the V-flame. In a stoichiometric flame, the leaner vortex enhances the decay of both OH and CH. In a rich flame, we observe an abrupt increase in OH-LIF signal and a disappearance of CH-LIF signal that are consistent with a previous experimental investigation. Our results indicate that the previously observed OH burst and CH breakage were caused by a difference in the equivalence ratios of the vortex pair and the main reactant flow. A numerical study shows that N{sub 2} dilution enhances the response of premixed flames to unsteady strain and variations in stoichiometry. Reaction-path and sensitivity analyses indicate that the peak OH and CH mole fractions exhibit significant sensitivity to the main branching reaction, H+O{sub 2} {r_reversible}OH+O. The sensitivity of OH and CH to this and other reactions is enhanced by N{sub 2} dilution. As a result, N{sub 2}-diluted flames provide a good test case for studying the reliability of chemical kinetic and transport models. (author)

  7. Transient design of landfill liquid addition systems.

    PubMed

    Jain, Pradeep; Townsend, Timothy G; Tolaymat, Thabet M

    2014-09-01

    This study presents the development of design charts that can be used to estimate lateral and vertical spacing of liquids addition devices (e.g., vertical well, horizontal trenches) and the operating duration needed for transient operating conditions (conditions until steady-state operating conditions are achieved). These design charts should be used in conjunction with steady-state design charts published earlier by Jain et al. (2010a, 2010b). The data suggest that the liquids addition system operating time can be significantly reduced by utilizing moderately closer spacing between liquids addition devices than the spacing needed for steady-state conditions. These design charts can be used by designers to readily estimate achievable flow rate and lateral and vertical extents of the zone of impact from liquid addition devices, and analyze the sensitivity of various input variables (e.g., hydraulic conductivity, anisotropy, well radius, screen length) to the design. The applicability of the design charts, which are developed based on simulations of a continuously operated system, was also evaluated for the design of a system that would be operated intermittently (e.g., systems only operated during facility operating hours). The design charts somewhat underestimates the flow rate achieved and overestimates the lateral extent of the zone of impact over an operating duration for an intermittently operated system. The associated estimation errors would be smaller than the margin of errors associated with measurement of other key design inputs such as waste properties (e.g., hydraulic conductivity) and wider variation of these properties at a given site due to heterogeneous nature of waste.

  8. Observations of some X-ray transients with RXTE

    NASA Astrophysics Data System (ADS)

    Borozdin, Konstantin N.; Priedhorsky, William C.; Revnivtsev, Mikhail G.; Emelyanov, Artem N.; Trudolyubov, Sergey P.; Titarchuk, Lev G.; Vikhlinin, Alexey A.

    2000-04-01

    We present results of observations of several X-ray transients with RXTE in 1996-1998, namely, GRS 1739-278, XTE J1748-288, GS 1354-64. 2S1803-245 and XTE J0421+560 (CI Cam). We studied light curves and spectra of their outbursts and compared them with observations of other X-ray transients. We discuss fits of high state spectra with BMC model, and similarities and differences between black holes and neutron stars in their low state. Special attention is paid to CI Cam as possible legate for new class of X-ray transients. .

  9. Observations of some x-ray transients with RXTE

    NASA Astrophysics Data System (ADS)

    Borozdin, K.; Priedhorsky, W.

    1999-11-01

    We present results of observations of several X-ray transients with RXTE in 1996-1998, namely, GRS 1739-278, XTE J1748-288, GS 1354-64, 2S1803-245 and XTE J0421+560 (CI Cam). We studied light curves and spectra of their outbursts and compared them with observations of other X-ray transients. We discuss fits of high state spectra with BMC model, and similarities and differences between black holes and neutron stars in their low state. Special attention is paid to CI Cam as possible legate for new class of X-ray transients.

  10. Detecting unstable periodic orbits from transient chaotic time series

    PubMed

    Dhamala; Lai; Kostelich

    2000-06-01

    We address the detection of unstable periodic orbits from experimentally measured transient chaotic time series. In particular, we examine recurrence times of trajectories in the vector space reconstructed from an ensemble of such time series. Numerical experiments demonstrate that this strategy can yield periodic orbits of low periods even when noise is present. We analyze the probability of finding periodic orbits from transient chaotic time series and derive a scaling law for this probability. The scaling law implies that unstable periodic orbits of high periods are practically undetectable from transient chaos.

  11. Characterization of surface states by SPV-transient

    NASA Astrophysics Data System (ADS)

    Sinkkonen, J.; Novikov, S.; Varpula, A.

    2008-11-01

    A model for the slow, large signal SPV-transient is developed which accounts for carrier trapping to surface states. Both majority and minority carrier processes are included. SPV-transients are measured from various epiready n +-GaAs wafers using Kelvin probe. Typically the transients take place in 1-1000 s time scale. By fitting the model with experimental results trapping parameters, i.e. surface potential barrier height, energy and density of surface states and electron and hole capture cross-sections are determined.

  12. Grounding system analysis in transients programs applying electromagnetic field approach

    SciTech Connect

    Heimbach, M.; Grcev, L.D.

    1997-01-01

    Lightning protection studies of substations and power systems require knowledge of the dynamic behavior of large grounding grids during electromagnetic transients. This paper presents strategies which allow to incorporate complex grounding structures computed using a rigorous electromagnetic model in transients programs. A novel technique for rational function representation of frequency-dependent grounding system impedances in the EMTP is described. An arbitrary number of feeding points can be modeled as mutual coupling is taken into account. Overvoltages throughout electrical power systems and the transient ground potential rise in the surroundings of grounding structures can be computed.

  13. Metabolic studies of transient tyrosinemia in premature infants

    NASA Technical Reports Server (NTRS)

    Fernbach, S. A.; Summons, R. E.; Pereira, W. E.; Duffield, A. M.

    1975-01-01

    The recently developed technique of gas chromatography-mass spectrometry supported by computer has considerably improved the analysis of physiologic fluids. This study attempted to demonstrate the value of this system in the investigation of metabolite patterns in urine in two metabolic problems of prematurity, transient tyrosinemia and late metabolic acidosis. Serial 24-hr urine specimens were analyzed in 9 infants. Transient tyrosinemia, characterized by 5- 10-fold increases over basal excretion of tyrosine, p-hydroxyphenyllactate, and p-hydroxyphenylpyruvate in urine, was noted in five of the infants. Late metabolic acidosis was seen in four infants, but bore no relation to transient tyrosinemia.

  14. Transient chaos in two coupled, dissipatively perturbed Hamiltonian Duffing oscillators

    NASA Astrophysics Data System (ADS)

    Sabarathinam, S.; Thamilmaran, K.; Borkowski, L.; Perlikowski, P.; Brzeski, P.; Stefanski, A.; Kapitaniak, T.

    2013-11-01

    The dynamics of two coupled, dissipatively perturbed, near-integrable Hamiltonian, double-well Duffing oscillators has been studied. We give numerical and experimental (circuit implementation) evidence that in the case of small positive or negative damping there exist two different types of transient chaos. After the decay of the transient chaos in the neighborhood of chaotic saddle we observe the transient chaos in the neighborhood of unstable tori. We argue that our results are robust and they exist in the wide range of system parameters.

  15. OBSERVATIONS OF SOME X-RAY TRANSIENTS WITH RXTE

    SciTech Connect

    K. BOROZDIN; W. PRIEDHORSKY; ET AL

    1999-11-01

    We present results of observations of several X-ray transients with RXTE in 1996-1998, namely, GRS 1739-278, XTE J1748-288, GS 1354-64, 2S1803-245 and XTE J0421+560 (CI Cam). We studied light curves and spectra of their outbursts and compared them with observations of other X-ray transients. We discuss fits of high state spectra with BMC model, and similarities and differences between black holes and neutron stars in their low state. Special attention is paid to CI Cam as possible legate for new class of X-ray transients.

  16. Transient Storage in Zero-Order Channels Draining Arctic Hillslopes

    NASA Astrophysics Data System (ADS)

    Cook, C. L.; Harms, T.; Wlostowski, A. N.; Gooseff, M. N.

    2015-12-01

    Water tracks are linear regions of preferential hydrologic flow on arctic hillslopes that discharge to lakes and higher-order streams. In comparison to headwater streams, which encompass flow velocities of 0.1 - 1.0 + m/s, water velocity in water tracks ranges 0.001 - 0.1 m/s, suggesting the potential for significant interaction of water and solutes with transient storage zones in hillslopes compared to streams. Transient storage, the temporary retention of water and solutes in slow-flowing water, contributes to increased water residence time and thus the exposure of water and associated solutes to biochemically reactive substrates. Seasonal patterns in thaw depth of hillslope soils and discharge from hillslopes in the Arctic suggest that the relative contribution of transient storage zones might show predictable seasonal- and event-scale patterns. We conducted slug injections of a conservative solute (NaCl) in two water tracks in the Kuparuk River watershed, Alaska, during two summers to characterize how transient storage varied with thaw depth and discharge. The resulting break-through curves were separated into three dominant processes using an analytical advection-dispersion model: 1) salt mass primarily moved by advection and dispersion, 2) salt mass experiencing transient storage, and 3) a mass loss term. Across all tracer experiments, the mean percentage of total injected tracer mass associated with transient storage was 54%. This is comparable to a peat-bottomed stream but greater than a cobble-lined channel in a nearby catchment. However, transient storage was variable among experiments (1.3 - 72%). Discharge was also variable across experiments, ranging 0.05 - 3.5 L/s, and there was a negative correlation between transient storage and discharge. Thus, we expect significant interaction of solutes with soils in water tracks during inter-storm periods, when the majority of water moving through water tracks enters transient storage zones. We did not see a

  17. Transient radiative energy transfer in incompressible laminar flows

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Singh, D. J.

    1987-01-01

    Analysis and numerical procedures are presented to investigate the transient radiative interactions of nongray absorbing-emitting species in laminar fully-developed flows between two parallel plates. The particular species considered are OH, CO, CO2, and H2O and different mixtures of these. Transient and steady-state results are obtained for the temperaure distribution and bulk temperature for different plate spacings, wall temperatures, and pressures. Results, in general, indicate that the rate of radiative heating can be quite high during earlier times. This information is useful in designing thermal protection systems for transient operations.

  18. „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.

  19. Werk und Leben Walter Christallers . Auszüge aus der Festrede anläßlich der Verleihung des Walter-Christaller-Preises 1996

    NASA Astrophysics Data System (ADS)

    Hottes, Ruth

    1997-03-01

    Unter der Betreuung und Federführung von Robert Gradmann promovierte am Erlanger Geographischen Institut 1932 Walter Christaller mit seiner Dissertation `Die Zentralen Orte in Süddeutschland'. Diese mit summa cum laude bewertete Monographie sollte die vielleicht berühmteste geographische Doktorarbeit unseres Jahrhunderts werden. Sie hat in den vergangenen Jahrzehnten einen beispiellosen Siegeszug angetreten. Heute gilt sie für Geographie, Raumwirtschaftslehre, Stadtforschung und Standorttheorie als eine bahnbrechende Grundkonzeption, und sie ist von größter Bedeutung für Raumordnungspolitik und Planungspraxis."

  20. Transient Global Amnesia: Emergency Department Evaluation And Management.

    PubMed

    Faust, Jeremy Samuel; Nemes, Andreea

    2016-08-01

    Transient global amnesia is a clinically distinct syndrome characterized by the acute inability to form new memories. It can last up to 24 hours. The diagnosis is dependent on eliminating other more serious etiologies including toxic ingestions, acute strokes, complex partial seizures, and central nervous system infections. Transient global amnesia confers no known long-term risks; however, when abnormal signs or symptoms are present, they take precedence and guide the formulation of a differential diagnosis and investigation. In witnessed transient global amnesia with classic features, a minimalist approach is reasonable, avoiding overtesting, inappropriate medication, and medical interventions in favor of observation, ensuring patient safety, and reassuring patients and their families. This review provides a detailed framework for distinguishing transient global amnesia from its dangerous mimics and managing its course in the emergency department.