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  • Univ. Berlin  (46)
  • Univ. Hamburg  (44)
  • English  (57)
  • German  (33)
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  • 2020-2023
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  • 2010  (90)
  • 1
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2020-10-07
    Description: The main topic of this work is the introduction of time dependence into PHOENIX. This has been achieved for both the radiation field and the matter in the SN Ia model atmosphere. First, time dependence in the radiative transfer equation has been implemented. Two discretization schemes have been used for the implementation of the time derivative. Test calculations have been performed to confirm the correctness of the implementations. The radiation time scale computed with the time dependent radiative transfer is comparable to a simple analytic approach. Perturbations of the inner boundary condition of the atmosphere move through the whole atmosphere. For instance, an atmosphere with a sinusoidally varying inner light bulb leads to an atmosphere where the luminosity varies sinusoidally everywhere. For the next extension of time dependence for the matter, a simple hydrodynamical solver has been implemented. It computes the changes in the energy of an SN Ia atmosphere by considering the homologous expansion, energy transport and the deposition of energy by g -ray emission due to the radioactive decay of 56Ni and 56Co. Test calculations verified that each part of the solver works correctly. The energy deposition heats the atmosphere and increases the observed luminosity, whereas the adiabatic e expansion cools the atmosphere. The energy transport always pushes the temperature structure of the atmosphere towards the radiative equilibrium state ...
    Description: thesis
    Keywords: 523 ; THI 000 ; THU 162 ; Helligkeit von Sternen {Astronomie} ; Supernovae {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 107 S.
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  • 2
    Publication Date: 2021-03-29
    Description: This work focuses on the distribution of atomic hydrogen in the exosphere of Saturns̉ moon Titan. This work is based on measurements performed by the Hydrogen Deuterium Absorption Cell (HDAC) aboard the Cassini spacecraft, that should directly determine the D/H ratio from the UV emission of atomic hydrogen and deuterium at 121.567 and 121.533 nm, respectively. HDAC measurements were performed on December 26, 2005 during the ninth Titan flyby of the Cassini orbiter. Unfortunately the amount of deuterium in the absorption cell could not be determined. Thus, the purpose, HDAC was designed for could not be achieved. For this reason, HDAC has performed measurements only once. However, the amount of atomic hydrogen in the absorption cell is well known, hence the data using only the hydrogen cell can be used in order to investigate Titans̉ exosphere. This work aims at simulating the HDAC measurements performed in order to investigate Titan’s exosphere, e.g. to determine the distribution of atomic hydrogen. A model of Titan’s exosphere including atomic hydrogen and methane has been developed and the transfer of solar radiation is calculated in order to simulate the HDAC measurements. The radiative transfer is solved using the Monte Carlo method. For the exospheric model, two different atomic hydrogen density distributions were applied, which determine the distribution in the exosphere by different approaches. Density profiles calculated by both models mainly differ in the lower exosphere ...
    Description: thesis
    Keywords: 523 ; TGG 655 ; Saturnmonde {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 171 S.
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  • 3
    Publication Date: 2021-03-29
    Description: Spectro-astrometry is a technique to obtain information about the structure of an astronomical source on sub-diffraction limited spatial scales down to milli- or micro-arcseconds. The method exploits the shift of the photocentre of a structured source over emission/absorption lines in its spectral energy distribution. Sub-diffraction limited resolution can be achieved because the method only uses wavelength-differential information of longslit spectra. Although spectro-astrometry has already been devised by Bailey (1998) and some studies have been performed to date on different astronomic targets, so far, no systematic analysis of the potential of this technique has been undertaken. The aim of this work was to analyse the potential of the method, develop the tools to exploit this potential and write the software which is needed to perform the analysis procedure. To verify the practical feasibility, observations were done with the VLT/CRIRES facility to demonstrate the capabilities of the method with respect to detecting structures on giant star surfaces. All steps of data reduction were analysed with respect to their influence on the spectro-astrometric quantities and a new method for bad pixel detection was devised and implemented ...
    Description: thesis
    Keywords: 523 ; THT 600 ; THK 000 ; THT 400 ; Riesensterne {Astronomie} ; Spektren und Spektroskopie von Sternen {Astronomie} ; Kalte Sterne {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 109 S.
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  • 4
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: This thesis deals with the high-energy emission from young stellar objects, which are on the one hand still actively accreting from their disk, and on the other hand are no longer deeply obscured by their natal cloud. Stars of spectral type B and A are called Herbig Ae/Be (HAeBe) stars in this stage, all stars of later spectral type are termed classical T Tauri stars (CTTS); strictly speaking both types are defined by spectroscopic signatures, which are equivalent to the evolutionary stage described above. In this thesis CTTS and HAeBes are studied through high-resolution X-ray and UV spectroscopy and through detailed physical simulations. Spectroscopic X-ray data is reduced and presented for two targets: The CTTS V4046 Sgr was observed with Chandra for 100 ks, using a high-resolution grating spectrometer. The lightcurve contains one flare and the He-like triplets of Si XIII, Ne IX and O VII indicate high densities in the X-ray emitting regions. The second target is the HAeBe HD 163296, which was observed with XMM-Newton for 130 ks. The lightcurve shows only moderate variability, the elemental abundance follows a pattern, that is usual for active stars. The He-like triplet of O VII exhibits line ratios similar to coronal sources, indicating that neither a high density nor a strong UV-field is present in the region of the X-ray emission ...
    Description: thesis
    Keywords: 523 ; THP 000 ; Thermodynamische Vorgänge in Sternen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 84 S.
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  • 5
    Publication Date: 2021-03-29
    Description: This thesis discusses dust formation in binary systems, in particular for binary systems consisting of a Mira like star and a brown dwarf. A Mira-like star is an intermediate mass star in a late stage of their stellar evolution on the Asymptotic Giant Branch (AGB), and a brown dwarf, is a sub-stellar object with a mass below that necessary to maintain hydrogen-burning nuclear fusion reactions in their cores. In their radial pulsating elevated convective atmospheres, Mira-stars often develop strong stellar winds, which are driven by radiation pressure on the dust and lead to a substantial mass-loss of the star. Stellar winds are of central importance for the development of medium-heavy-AGB stars. Also, they are a reliable source for the production of dust particles and heavy elements for the interstellar medium and the chemical evolution of galaxies. In fact, most stars are in binary or multiple star systems.For a complete description of the processes of dust formation in binary star systems it is necessary to study the perturbative influence of a second star in the vicinity of a AGB-star with a strong stellar wind. This endeavour is embedded in a long standing tradition of scientific investigation of dust formation at the Zentrum für Astronomie und Astrophysik (ZAA) at the Technical University of Berlin...
    Description: thesis
    Keywords: 523 ; THT 900 ; TII 900 ; Doppelsterne {Astronomie} ; Interstellarer Staub {Astronomie: Interstellare Materie}
    Language: English
    Type: monograph , publishedVersion
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  • 6
    Publication Date: 2021-03-29
    Description: Many stars evolve not alone but along one or more companions. While the evolution of single isolated stars is well predicted by theoretical calculations, close binary systems with their interactions are on the one hand far more difficult to handle, but on the other hand well constrained in their masses and sizes. One mechanism thought to produce such close binaries is the Common Envelope Evolution (CEE). Especially young post CEE binaries show great temperature differences between both components of about a factor 10 at a separation of just a few solar radii. This work focuses on close binary systems with a hot primary component (e.g. a subdwarf O-type star (sdO)) and a much cooler secondary component (e.g. a main-sequence star), which is heavily influenced by external radiation originating from the first. The technique to include external radiation into the stellar atmosphere code PHOENIX, i.e., the deviation of the outer boundary condition and the change in the temperature correction method, is described in detail. To concentrate on the irradiation effect, other difficulties such as asymmetric effects due to tear-drop shaped stars, ongoing mass accretion or shadows of a circumbinary disc, are avoided by selecting pre-cataclysmic variables (pre CVs) out of the class of close binaries as laboratory. The total eclipsing binary system UU~Sagittae is used as an example for massive irradiation and observed spectral features in the optical are fitted ...
    Description: thesis
    Keywords: 523 ; THK 000 ; THT 900 ; Spektren und Spektroskopie von Sternen {Astronomie} ; Doppelsterne {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 100 S.
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  • 7
    Publication Date: 2021-03-29
    Description: The first extrasolar planet 51 Peg b around the G-type star has been reported in 1995. The planet with few Jupiter masses orbiting its star very closely was detected by measurement of the oscillation in the radial velocity of the host star. In 1999 the first transit, when the planet is eclipsing the host star, of the extrasolar planet HD209458 b was observed with a small ground based photometric telescope. Ever since, new planets in distant systems are continuously being detected with new high precision instruments from the ground and from space. The department of Extrasolar Planets and Atmospheres at Deutsches Zentrum für Luft- und Raumfahrt, Berlin (DLR) is involved in the detection and characterization of extrasolar planets, through participation in the CoRoT space mission. Furthermore, two ground based photometric telescope systems are operated as a ground based support for the space mission CoRoT, dedicated to asteroseismology and to extrasolar planet search with the help of the transit method. The BEST project consists of two small aperture wide field-of-view photometric telescopes devoted to the search for transiting Jupiter-sized extrasolar planets and to the characterization of variable stars in CoRoT target fields...
    Description: thesis
    Keywords: 523 ; THX 100 ; TJ 900 ; TCE 220 ; Detektionsmethoden {Astronomie: Extrasolare Planetensysteme} ; Einzelne Weltraumprojekte ; Bodenständige UV-, Optische und Infrarotteleskope {Astronomische Instrumente}
    Language: English
    Type: monograph , publishedVersion
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  • 8
    Publication Date: 2021-03-29
    Description: Das Antarctic Muon And Neutrino Detector Array (AMANDA) ist ein Cherenkov Detektor, der sich im Gletscher der Antarktis am Südpol befindet. Wir präsentieren die Analyse von Daten, die in den Jahren 2000 bis 2004 gesammelt wurden, die einer effektiven Detektorlaufzeit von 1001 Tagen entsprechen. Die Suche zielt auf den Nachweis von elektomagnetische und hadronische Teilchenschauern, so gennante Kaskaden, die durch Elektron- und Tauneutrinowechselwirkung produziert werden können. Die hadronischen Kaskaden können auch über neutrale Ströme Wechselwirkung von Neutrinos aller Arten produziert werden. Der Kaskadenkanal hat einige Vorteile in der Suche nach einem diffusen Fluss von astrophysikalischen Neutrinos. Durch die gute Energieauflösung des AMANDA Detektors kann man zwischen einem harten astrophysikalische Spektrum und einem weichen atmosphärischen Spektrum unterscheiden. Außerdem ist der atmosphärischen Elektronneutrinos Fluss um eine Gößenordnung kleiner als der atmosphärische Myonneutrinofluss. Der Untergrund von atmosphärischem Myonen aus Luftschauern kann unterdrückt werden, weil diese als Spuren im Detektor erscheinen und leicht zu identifizieren sind...
    Description: thesis
    Keywords: 539.7215 ; 523 ; 550 ; TBN 000 ; TCE 500 ; Neutrino-Astronomie ; Sonstige Instrumente {Astronomische Instrumente}
    Language: English
    Type: monograph , publishedVersion
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  • 9
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: Magnetic cataclysmic variables, also called AM Her stars or 'polars', are close binaries with mass transfer (accretion), consisting of a late-type main-sequence star (commonly called secondary)and a more massive white dwarf with a strong magnetic field. The late-type star is losing mass to the white dwarf. The overflowing matter firstly follows a ballistic trajectory and is then captured by the magnetic field of the white dwarf and guided along the field lines onto the white dwarf. The released gravitational energy is radiated away in all wavelength ranges from infra-red to X-ray. The observed light of an AM Her system is composed of the contributions from the stellar components and the contributions of the accretion column and the accretion region on the white dwarf. The last two components are not only depending on the actual mass transfer rate but also from the spatial orientation of the magnetic field. Since the white dwarf is locked in synchronous rotation, this leads to emission that varies with orbital phase. The decomposition of the observed light from an AM Her system makes it possible to analyse the different components within this system...
    Description: thesis
    Keywords: 523 ; THK 000 ; Spektren und Spektroskopie von Sternen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 140 S.
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  • 10
    Publication Date: 2021-03-29
    Description: The term "stellar activity" summarizes a number of phenomena on the stellar surface and in the stellar atmosphere. The origin of many of these phenomena are changes in the structure of the stellar magnetic field. While it is possible to directly observe different forms of activity on the Sun in great detail, this remains impossible for other stars. However, by analyzing the spectra of these stars, information about their activity can be obtained. This thesis addresses two aspects of activity: First, the X-ray emission from the positions of A-type stars and a possible mechanism to produce these X-rays and second, the chromospheric activity in the spectral range from late A- to late K-type stars. Since the dynamo, which is responsible for the activity of solar-like stars, emerges in the range of late A- to early F-type stars, this spectral range is of special interest for the understanding of the activity phenomena. To study the X-ray activity of A-type stars, their optical positions as given in the Bright Star Catalogue were compared with the positions of the X-ray sources listed in the ROSAT catalogs. The matching criteria for the ROSAT All-Sky Survey data were 90 arcseconds, 36 arcseconds for the pointing observations with the PSPC and 18 arcseconds for HRI data. Those stars which could be associated with X-ray sources were tested for indications of hidden late-type companions. Variations in the radial velocity, the proper motion, and the light curve were interpreted as signs for binarity...
    Description: thesis
    Keywords: 523 ; THP 000 ; THN 400 ; Thermodynamische Vorgänge in Sternen {Astronomie} ; Sternatmosphären {Astronomie}
    Language: English
    Type: monograph , publishedVersion
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  • 11
    Publication Date: 2021-03-29
    Description: Die Natur der dunklen Materie ist nach wie vor ungeklart und stellt eine der fundamentalsten Fragen der aktuellen Kosmologie dar. In vielen verschiedenen Experimenten wird versucht, diese Teilchen, die sogenannten WIMPs (aus dem Englischen: Weakly Interacting Massive Particles), nachzuweisen. In einigen Modellen der dunklen Materie wird vorhergesagt, dass sehr hochenergetische -Strahlung durch Annihilation der WIMPs in konzentrierten Ansammlungen dunkler Materie produziert wird. Im Rahmen der vorliegenden Arbeit wurden anhand von Beobachtungen im Energiebereich von 100 GeV bis 100 TeV mit dem System abbildender Cherenkov-Teleskope des H.E.S.S.-Experiments (aus dem Englischen: High Energy Stereoscopic System) verschiedene Objekte untersucht, ob die gemessene Strahlung ihren Ursprung in der Annihilation von Teilchen dunkler Materie haben konnte. Das Zentrum unserer Galaxie ist ein in der Literatur viel diskutierter Bereich, in dem sehr hochenergetische -Strahlung aus Annihilation dunkler Materie entstehen konnte. Es wurde mit H.E.S.S. sehr hochenergetische -Strahlung aus dieser Richtung nachgewiesen. Es wird aber gezeigt, dass die gemessene Strahlung aus der Richtung des galaktischen Zentrums nicht ausschlie lich von dunkler Materie erzeugt wird. Daher wurde zusatzlich untersucht, welche Aussagen mit der Hypothese getro en werden konnen, dass nur ein Anteil aus dieser Strahlung besteht. Es konnten interessante Einschrankungen auf das Dichtepro l der hypothetischen DM-Ansammlung gewonnen werden; ein Dichtepro l nach Moore kann fur viele Parametersatze der untersuchten Modelle ausgeschlossen werden. Auf den Wirkungsquerschnitt der Annihilation kann keine relevante Einschrankung erzielt werden..
    Description: thesis
    Keywords: 523 ; 550 ; TII 100 ; TIE 650 ; Dunkle Materie {Astronomie: Interstellare Materie} ; Milchstrasse {Astronomie}
    Language: German
    Type: monograph , publishedVersion
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  • 12
    Publication Date: 2021-03-29
    Description: In this work, nonanalytical line profiles for both cool and hot, dense atmospheres are added to the opacity calculations of the multipurpose stellar atmosphere code PHOENIX. Their influence on model atmospheres and synthetic spectra is studied. Model atmospheres are necessary in order to calculate synthetic spectra and to derive reliable stellar parameters. For cool, dense atmospheres, i.e., of objects of spectral type similar to and lower than latetype M, vanderWaals broadening is the most important pressure broadening mechanism. The spectra of these objects below ~1 micro-meter are dominated by alkali resonance lines. The profiles of the alkali resonance lines, especially of Na ID and KI, determine mostly the pseudo continuum in this wavelength range. Up to this work, classical analytical impact approximated alkali near line wing profiles perturbed by H2, He, and HI, which are the dominant perturbing particles, have been applied. In this work, various nonanalytical alkali line profiles, including far line wing and near line wing profiles, for Na I D, Li I, KI, and Rb I are included in order to describe the strong alkali absorption features which are characteristic for latetype dwarfs. For the alkali resonance line profiles, different theoretical approaches were used describing the far and near line wings. Non analytical alkali profiles for the far and near line wings perturbed by H2 and He are provided in the unified semiclassical theory...
    Description: thesis
    Keywords: 523 ; 550 ; THN 400 ; THK 000 ; Sternatmosphären {Astronomie} ; Spektren und Spektroskopie von Sternen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 156 S.
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  • 13
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: This work covers the dominant aspects of landforms and processes related to the cold-climate (periglacial) and hyperarid environment of Mars and relates the knowledge obtained from terrestrial research to possible Martian analogue landforms. Among the plethora of landforms related to cold-climate environments and subsurface permafrost on Mars, those features have been investigated in detail that are related to the creep of ice and debris at the Martian dichotomy escarpment and the southern-hemispheric impact basins, especially Hellas Planitia, and which have been described controversially as either glacial or periglacial in nature. Structures related to seasonal freeze-thaw cycles on Mars which are generally known as thermal contraction polygons form a second major focus of this work. Research presented on this topic focuses on the northern hemispheric Utopia Planitia area and the south-polar cap of Mars. This work was carried out on the basis of observational and geomorphometrical analyses by utilizing imaging-sensor and topographic data in order to address questions regarding the history, development, and current state of cold-climate landforms on Mars. This work provides new insights with respect to age, composition, source of debris and ice, and the deformational and degradational history of lobate debris aprons and similar landforms. It is shown that processes which led to creep of debris and ice at the northern hemispheric dichotomy boundary are transitional in nature and are not easily categorized using standard definitions commonly used in terrestrial research...
    Description: thesis
    Keywords: 523 ; 550 ; V 600 ; VAR 800 ; TGG 545 ; Grenzgebiete. Beziehungen. Wirkungen. Einflüsse {Geologische Wissenschaften} ; Periglazialerscheinungen ; Marsoberfläche {Astronomie}
    Language: German
    Type: monograph , publishedVersion
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  • 14
    Publication Date: 2021-03-29
    Description: The subject of this work is the physical characterization of asteroids, with an emphasis on the thermal inertia of near-Earth asteroids (NEAs). Thermal inertia governs the Yarkovsky effect, a non-gravitational force which significantly alters the orbits of asteroids up to ~20 km in diameter. Yarkovsky-induced drift is important in the assessment of the impact hazard which NEAs pose to Earth. Yet, very little has previously been known about the thermal inertia of small asteroids including NEAs.Observational and theoretical work is reported. The thermal emission of asteroids has been observed in the mid-infrared (5-35 æm) wavelength range using the Spitzer Space Telescope and the 3.0 m NASA Infrared Telescope Facility, IRTF; techniques have been established to perform IRTF observations remotely from Berlin. A detailed thermophysical model (TPM) has been developed and extensively tested; this is the first detailed TPM shown to be applicable to NEA data.
    Description: thesis
    Keywords: 523 ; 550 ; TGG 900 ; Planetoide {Astronomie}
    Language: English
    Type: monograph , publishedVersion
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  • 15
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 523 ; 550 ; TH0 000 ; THP 000 ; THT 600 ; Asteroseismologie, Oszillation {Sterne} ; Thermodynamische Vorgänge in Sternen {Astronomie} ; Riesensterne {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 135 S.
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  • 16
    Publication Date: 2021-03-29
    Description: In dieser Doktorarbeit wurden im Rahmen des MAGIC Experimentes neue Datenanalysemethoden implementiert, die sich insbesondere fuer die Analyse von Ereignissen niedriger Gammastrahlungsenergie eignen. Die Methoden konnten erfolgreich in Monte Carlo Studien getestet und auf Beobachtungsdaten des Krebsnebels und der extragalaktischen Gammastrahlungsquelle PG1553+113 angewandt werden. Diese Methoden reichen von ''image cleaning'' Techniken und der Nutzung neuer Bildparameter bis zu fortgeschrittenen g/h-Separations- und Energieabschaetzungsverfahren. Zum ersten Mal wurden die Vorteile von Klassifikations- und Regressionsbaeumen in der Gamma-Astrophysik ausgenutzt, um existierende klassische Methoden zu verbessern. Die Analyse - getestet an Monte Carlo Daten - bewies ihre Zuverlaessigkeit bei der Untersuchung der Gammastrahlungsemission des Krebsnebels, wobei ein hochsignifikanter Exzess im Energiebereich unterhalb 100 GeV in nur 1.7 h nachgewiesen werden konnte. Die Analyse von Daten des BL Lac Objekts PG1553+113 ergab signifikante Exzesse fuer Beobachtungen in den Jahren 2005 und 2006. Das kombinierte alpha-Histogramm zeigt ein Signal mit einer Signifikanz, die 8 sigma ueberschreitet...
    Description: thesis
    Keywords: 523 ; TBK 000 ; THT 200 ; Hochenergieastronomie ; Sterne einzelner Spektralklassen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 195 S.
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  • 17
    Publication Date: 2021-03-29
    Description: Die H.E.S.S. Kollaboration betreibt ein stereoskopisches System aus vier großen abbildenden Cherenkov-Teleskopen für den Nachweis sehr hochenergetischer Gamma-Strahlung (VHE; 〉 100 GeV). In dieser Arbeit wird über den Nachweis zweier neuer Quellen sehr hochenergetischer Gamma-Strahlung mit den H.E.S.S.-Teleskopen berichtet. Die extragalaktische Quelle 1ES0347-121 gehört zur Klasse der BL Lac Objekte und ist der aktive Kern einer entfernten Galaxie. Detektiert mit einer Signifikanz von mehr als 10 Standard-Abweichungen, ist es die bisher am weitesten entfernte Quelle sehr hochenergetischer Gamma-Strahlung (Rotverschiebung z = 0.1880). Ihr Energiespektrum läßt sich gut durch ein Potenzgesetz mit Photonindex Gamma = 3.08 +/- 0.23_stat +/- 0.1_sys beschreiben. Der integrale Fluss I(E 〉250GeV) entspricht ~2% des Flusses des Krebsnebels. Mit Hilfe des hochenergetische Gamma-Strahlungsspektrum von 1ES 0347-121 werden Einschränkungen auf die Dichte des extragalaktischen diffusen Photonfeldes bestimmt (s. unten). Bei der zweiten Quelle handelt es sich um die ausgehnte Quelle HESS J1023-577, die mit dem jungen, massiven Sternenhaufen Westerlund 2 und dessen Umgebung assoziert wird. Junge und massereichen Sterne strahlen starke Sternenwinde ab, die durch Schockbeschleunigung hochenergetische Teilchen produzieren können. Zum erstenmal konnte eine Quelle sehr hochenergetischer Gamma-Strahlung mit einer solchen Umgebung sicher identifiziert werden. Das Energiespekrum reicht von ~400GeV bis ~20TeV und läßt sich gut durch eine Potenzgesetz mit Photonindex Gamma=2.53 +/- 0.16_stat +/- 0.1_syst beschreiben.
    Description: thesis
    Keywords: 523 ; TIE 400 ; TBK 000 ; TCE 240 ; Spektren und Leuchtkraft von Sternsystemen {Astronomie} ; Hochenergieastronomie ; Röntgen- und Gammateleskope {Astronomische Instrumente}
    Language: English
    Type: monograph , publishedVersion
    Format: 123 S.
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  • 18
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 523 ; THP 000 ; Thermodynamische Vorgänge in Sternen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 76 S.
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  • 19
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: Comets belong to the most pristine objects in the Solar System. The study of comets therefore allows one to put constraints to the physical and chemical conditions in the pre-planetary disc. In this work, a one-dimensional simplified multi-fluid model for the analysis of the chemistry in cometary comae was constructed. This model was used for the study of the formation of the C3 and C2 radicals. For this purpose, radial profiles of the optical emissions of C3 and C2 in comets C/2001 Q4 NEAT, C/2002 T7 LINEAR, and 9P/Tempel 1 at heliocentric distances between 1.0 AU and 1.5 AU were analysed. These profiles were obtained by means of long-slit spectroscopy. A reaction network for the formation of C3 and C2 at larger heliocentric distances (Helbert 2002) was updated and extended. Molecules and radicals were identified for which photodissociation reaction rates have to be further constrained before the formation of C3 and C2 can be understood. As comets of special interest, the comets 67P/Churyumov-Gerasimenko and 9P/Tempel 1 were studied in more detail. Both comets are targets of space missions...
    Description: thesis
    Keywords: 523 ; TGL 200 ; Kometen {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 227 S.
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  • 20
    Publication Date: 2021-03-29
    Description: Diese Arbeit beschreibt die Verbesserung der Richtungsstabilisierung des Flugzeugteleskops SOFIA. Das Ziel des Flugzeugteleskops SOFIA sind astronomische Beobachtungen im Infrarotbereich. Da der Wasserdampf der Erdatmosphäre den Großteil der Infrarotstrahlung absorbiert, sind solche Beobachtungen mit herkömmlichen Teleskopen von der Erdoberfläche aus kaum möglich. Um unerwünschte Drehbewegungen des Flugzeugteleskops, z.B. hervorgerufen durch Luftturbulenzen, auszugleichen, ist zuerst eine genaue Messung bzw. Schätzung derselben notwendig. Diese Informationen werden dann mittels Computer in Echtzeit weiterverarbeitet. Anschließend sorgen dann Motoren dafür, das Teleskop wieder in die gewünschte Lage zu drehen. Die Motoren können das Teleskop nur so genau ausrichten, wie es die Genauigkeit des Meßsystems zuläßt. Die Messung der Drehbewegungen geschieht mit drei zueinander senkrecht angeordneten Gyroskopen. Diese weisen jedoch Fehler auf, so daß sich die Ausrichtgenauigkeit verschlechtert. Deshalb werden mit Hilfe einer auf das Teleskop montierten Kamera in regelmäßigen Zeitabständen Bilder des Sternhimmels aufgenommen. Aus diesen Bildern wird dann mit Hilfe der dort sichtbaren Sterne die aktuelle Orientierung des Teleskops bestimmt. Mittels dieser Orientierung werden dann die Fehler der Gyroskope korrigiert und der lineare Fehleranteil für die Zukunft extrapoliert. Dieser Fehler wird dann schon im Voraus vom Teleskoplageregler berücksichtigt. Dadurch wird der quasikonstante Fehleranteil minimiert. Je besser dieser Fehler geschätzt wird, desto geringer ist die Drift des Teleskops um seine Achsen. Dadurch erhöht sich die Richtungsstabilisierung ...
    Description: thesis
    Keywords: 522 ; TCE 200 ; Teleskope {Astronomische Instrumente}
    Language: German
    Type: monograph , publishedVersion
    Format: 125 S.
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  • 21
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: Unter stellarer Aktivität werden eine Reihe von Phänomenen in den unterschiedlichen Atmosphärenschichten zusammengefasst, die eng mit dem Magnetfeld des einzelnen Sterns verbunden sind. Da eine direkte Auflösung der Sternoberfläche, wie uns dies bei der Sonne möglich ist, für aktive Sterne noch in ferner Zukunft liegt, können diese Phänomene im Normalfall nicht direkt beobachtet werden. Es können aber aus der Spektralanalyse indirekt Informationen über die Aktivität eines Sterns gewonnen werden. Die vorliegende Arbeit beschäftigt sich mit koronaler und chromosphärischer Aktivität von mittleren und späten M Sternen und deren Nachweis und Analyse in UVES Echelle-Spektren von 3030 bis 3880 und 4580 bis 6680 A. Dabei widmet sich der erste Teil der Arbeit dem Nachweis der verbotenen koronalen Fe XIII Linie bei 3388 A. Das mehrere Millionen Kelvin heiße koronale Gas wird normalerweise - und am leichtesten - im Röntgenbereich beobachtet...
    Description: thesis
    Keywords: 523 ; THK 000 ; THN 400 ; Spektren und Spektroskopie von Sternen {Astronomie} ; Sternatmosphären {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 101 S.
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  • 22
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: The high ionization state of the intergalactic medium (IGM) is maintained by the metagalactic UV background radiation. This ionizing radiation field is supposed to be the integrated radiation of quasars and young star-forming galaxies, which is reprocessed and attenuated by the intergalactic gas. Since the UV background is inaccessible to direct observations, it is impossible to test theoretical predictions of its spectral energy distribution in great detail. However, constraints can be derived from studies of metal absorption systems, the HI Lyman alpha opacity, or the HeII Lyman alpha forest, respectively. Observations of the HeII/HI column density ratio eta particularly probe the variations of the UV background. Since unobscured quasars permitting observation of HeII absorption are rare, there are only two lines of sight, towards the quasars HE2347-4342 and HS1700+6416, where the HeII Lyman alpha forest can be resolved. This work presents a study of the UV background at redshifts z 〈 3 investigating the HeII absorption towards the quasars HS1700+6416 (z = 2.72), which provides the second line of sight where the HeII Lyman alpha forest is resolved. The numerous metal line systems detected in the spectra of this QSO are studied in order to avoid biases due to unrecognized metal line absorption in the HeII forest. In this connection, several shapes of the ionizing radiation are tested for each system. The majority of the considered systems, in particular those at z 〉 2, is best reproduced with an ionizing radiation similar to the UV background of Haardt & Madau (2001), where the HeII break, formally located at 4 Ryd, is shifted to lower energies (~ 3 Ryd), probably due to the opacity of the higher HeII Lyman series lines ...
    Description: thesis
    Keywords: 523 ; TIE 400 ; TBI 000 ; Spektren und Leuchtkraft von Sternsystemen {Astronomie} ; Ultraviolett-Astronomie
    Language: English
    Type: monograph , publishedVersion
    Format: 131 S.
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  • 23
    Publication Date: 2021-03-29
    Description: Die Untersuchung der Oberflächenzusammensetzung von Ganymed basiert auf Daten des abbildenden Spektrometers NIMS an Bord der Raumsonde Galileo, das die Ganymedoberfläche im Spektralbereich des Nahen Infrarot detektiert. Die Verarbeitung der vorliegenden Spektraldaten einschließlich der quantitativen Analyse der spektralen Signaturen in den Reflexionsspektren von Ganymed wie deren Charakterisierung in Abhängigkeit der geologischen Oberflächenstrukturen bildet den zentralen Teil der Arbeit. Die Ergebnisse zeigen, dass Veränderungen der Reflexionseigenschaften der Ganymedoberfläche auf den wechselnden Anteil von Wassereis und Gesteinsmaterial und dem Gehalt an CO2 zurückzuführen sind. Die simultane Analyse der Absorptionen von Wassereis erlaubt es ferner, erstmals Veränderungen des relativen Anteils und der Partikelgröße von Wassereis getrennt voneinander zu erfassen...
    Description: thesis
    Keywords: 523.45 ; 550 ; TGG 605 ; Jupitermonde {Astronomie}
    Language: German
    Type: monograph , publishedVersion
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  • 24
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 523 ; TIE 900 ; TBG 000 ; TC 200 ; Sonstige Sternensysteme {Astronomie} ; Infrarot-Astronomie ; Astronomische Beobachtungen vom Weltraum aus
    Language: English
    Type: monograph , publishedVersion
    Format: 181 S.
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  • 25
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: AM Herculis stars (or 'polars') are close binaries consisting of a white dwarf with a strong magnetic field and a main sequence star (the 'secondary') which is losing mass to the white dwarf. The magnetic field channels the matter to the magnetic poles, where the released potential energy is radiated away - mainly in X-rays and the UV. The spatial structure of these objects cannot be observed directly, because their apparent size is too small. Indirect imaging methods are capable of restoring information which is only contained in observational data as projections onto a sub-space. These tomographic methods are known from medicine, but can also be applied to astronomical data, when a number of measurements can be regarded as views of the same object under different aspect angles. In this work tomographic methods are applied to time-resolved spectroscopic data of polars. Spectral lines seen in the radiation emitted by the constituents of these systems are notably Doppler-shifted. The Doppler-shift is depending on the viewing angle of the system ('inclination') and is varying with orbital phase. Time-series of one-dimensional data (spectra) can be used to create a two-dimensional map of the intensity distribution in velocity-space (Doppler-tomography), or a map of the line-flux on the assumed surface of the mass-losing star (Roche-tomography) from the line profile changes ...
    Description: thesis
    Keywords: 523 ; THT 900 ; THU 155 ; Doppelsterne {Astronomie} ; Eruptionsveränderliche {Astronomie: Sterne}
    Language: English
    Type: monograph , publishedVersion
    Format: 124 S.
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  • 26
    Publication Date: 2021-03-29
    Description: The aim of this thesis is to obtain as much information as possible, about global solutions of the Cauchy problem for the Einstein-Vlasov-scalar field system with spherical, plane and hyberbolic symmetries written in areal coordinates. The sources of this system are generated by both a distribution function and a linear scalar field subject to the Vlasov and wave equations respectively. This system describes the evolution of self-gravitating collisionless matter and scalar waves within the context of general relativity. We consider the cosmological case. That is spacetimes possess a compact Cauchy hypersurface and then, data are given on a compact 3-manifold. We extend the local-in-time results obtained by G. Rein for the Einstein-Vlasov system with collisionless matter alone. This extension concerns pointwise estimates for hyperbolic equations by the method of characteristics. This means that the system is transformed to a system of ordinary differential equations which are integrated along characteristics ...
    Description: thesis
    Keywords: 523 ; TFA 000 ; Relativistische Astrophysik, Gravitation
    Language: English
    Type: monograph , publishedVersion
    Format: 85 S.
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  • 27
    Publication Date: 2021-03-29
    Description: Die physikalischen Ursachen für das Auftreten massiver Winde bei entwickelten Sternen sind weitgehend unverstanden. Aus diesem Grund ist es bisher noch nicht gelungen, von einer empirischen Beschreibung des Phänomens zu einem befriedigenden hydrodynamischen Ansatz überzugehen. Auch die üblichen diagnostischen Methoden ergeben kein einheitliches Bild der Windeigenschaften und können charakteristische Feinstrukturen in hochaufgelösten Spektren nicht erklären. Zudem ist nicht verstanden, ob die widersprüchlichen Ergebnisse der Analysen von Einzelsternen und Doppelsternsystemen von intrinsischer Natur sind oder methodische Unzulänglichkeiten widerspiegeln. Die in den Winden beobachteten Überschallturbulenzen scheinen eine zentrale Rolle für das Verständnis der dynamischen Prozesse zu spielen. In den üblichen Analyseverfahren wird diese Geschwindigkeitskomponente in der einfachen mikroturbulenten Approximation beschrieben. Es ist allerdings fraglich, ob die komplexe Struktur der Winde dadurch adäquat erfasst wird. Ein von Traving (1975) entwickeltes alternatives Turbulenzmodell gestattet es, Geschwindigkeitskorrelationen in einer stochastischen Näherung zu berücksichtigen ...
    Description: thesis
    Keywords: 523 ; THP 000 ; Thermodynamische Vorgänge in Sternen {Astronomie}
    Language: German
    Type: monograph , publishedVersion
    Format: 137 S.
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  • 28
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; VBQ 900 ; VBQ 800 ; VEO 170 ; Hydrogeologie einzelner Regionen ; Aquifere {Hydrogeologie} ; Sudan {Geologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 133 S.
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  • 29
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 560 ; VDH 200 ; VEX 100 ; VWH 200 ; VZX 100 ; VKB 380 ; Jura ; Anden {Geologie} ; Jura {Stratigraphische Paläontologie} ; Anden {Paläontologie} ; Sedimente bestimmter Regionen
    Language: German
    Type: monograph , publishedVersion
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  • 30
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 910 ; 551 ; VBQ 900 ; VEB 213 ; VJC 110 ; Hydrogeologie einzelner Regionen ; Brandenburg, Sachsen-Anhalt & Mecklenburg-Vorpommern {Geologie} ; Geochemie des Grundwassers, Porenwassers
    Language: German
    Type: monograph , publishedVersion
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  • 31
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 549 ; VGB 700 ; VGA 300 ; VHB 820 ; Spektroskopische Methoden {Mineralogie} ; Kristallstrukturen ; Inselsilikate {Mineralogie}
    Language: German
    Type: monograph , publishedVersion
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  • 32
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 549 ; VHB 850 ; VGF 200 ; Kettensilikate {Mineralogie} ; Phasengleichgewichte und Umbildungen {Mineralogie}
    Language: English
    Type: monograph , publishedVersion
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  • 33
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; VQC 000 ; VRA 110 ; VTG 000 ; Lagerstättengenese ; Eisenerz {Lagerstättenkunde} ; Osteuropa und Asiatische Teile der ehemaligen Sowjetrepubliken {Rohstoffgeologie}
    Language: German
    Type: monograph , publishedVersion
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  • 34
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; VGA 420 ; Optische Methoden {Mineralogie: Kristallographie}
    Language: German
    Type: monograph , publishedVersion
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  • 35
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: The Levantine Basin - a seismic investigation of the crustal structure and the evolution of the Messinian evaporites ABSTRACT This work presents an analysis of the crustal structure of the Levantine Basin, based on refraction seismic and gravity data, and an analysis of the evolution of the Messinian evaporites, based on reflection seismic data. Forward and inverse modelling of refraction seismic traveltimes along two profiles yielded 2-D velocity-depth-profiles. Gravity modelling along these profiles provided further information on the crustal structure. A great number of reflection seismic profiles was used for the analysis of the Messinian evaporites, which allowed an exhaustive investigation of the geometry of the evaporite layers, depositional phases of the evaporites and of their structural evolution. The Levantine Basin is located in the Southeastern Mediterranean Sea. The basin and its margin are key areas for the understanding of the geodynamic evolution of the Eastern Mediterranean. The opening of the Levantine Basin is closely related to the opening of the Neo-Tethys. Many geodynamic reconstructions of this area have been developed, but the key question, the origin of the crust, remained open. The Levantine Basin is also a world class site for studying the initial stages of salt tectonics driven by differential sediment load. The Messinian evaporites are comparatively young (deposited during the Messinian Salinity Crisis 5.9 - 5.3 Ma ago), the sediment load varies along the basin margin, they are hardly tectonically overprinted, and the geometry of the basin and the overburden is well-defined...
    Description: thesis
    Keywords: 550 ; TSF 000 ; VAE 820 ; VEF 000 ; Südeuropa und Mittelmeergebiet {Geophysik} ; Sedimentationsbecken als Erdkrustentypen {Geologie} ; Südeuropa und Mittelmeergebiet {Geologie}
    Language: English
    Type: monograph , publishedVersion
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  • 36
    Publication Date: 2021-03-29
    Description: Central Asia is characterized by a number of spectacular tectonic units such as the Tibetan Plateau, the Tien Shan intra-continental mountain belt and the Altyn Tagh strike-slip fault. Deformation of the lithosphere of these units is not well understood. In this dissertation, an attempt is made to answer the following tectonic questions: To what extent do the tectonic units formed in the upper crust in the course of the convergence between India and Eurasia weaken the underlying lithosphere? How is the Tibetan Plateau gravita-tionally compensated along its northern boundary? Do the Altyn Tagh and/or West Kunlun faults persist as vertical strike-slips throughout the crust and mantle lithosphere, thus representing a fundamental plate boundary? Which dynamic processes in the crust and mantle of the Tien Shan are responsible for intra-continental mountain building? What characterizes the local stress field in the Tien Shan and what causes the deformation of these mountains? To answer these questions, the elastic plate theory is used to interpret gravity and topography data, and in turn to derive specific characteristics of the lithospheric structure in Central Asia. Theoretical deflection of the elastic plate or plates were calculated using the 3D and 2D finite-difference methods. Variable-rigidity elastic plates are subjected to vertical and horizontal loads, shear forces, and terminal bending moments. Surface topo-graphic data from the Topo30 dataset is used as vertical surface loading to calculate the flexure of the elastic lithosphere...
    Description: thesis
    Keywords: 551.8 ; 622.15 ; 551 ; 550 ; VAE 400 ; VEK 000 ; TQA 000 ; TSK 000 ; VAE 400 ; VEK 000 ; TQA 000 ; TSK 000 ; Tektogenese {Geologie} ; Zentralasien {Geologie} ; Gravimetrische Verfahren {Geophysik} ; Zentralasien {Geophysik}
    Language: English
    Type: monograph , publishedVersion
    Format: 136 Bl.
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  • 37
    Publication Date: 2021-03-29
    Description: Mit der Annahme schwacher Anisotropie vereinfachen sich die Lösungen der Modellierung und Inversion anisotroper Medien. Üblicherweise werden Perturbation-Methoden zur Beschreibung der Wellen-Ausbreitung in schwach anisotropen Medien verwendet, ein anisotropes Medium wird ersetzt durch ein isotropes Hintergrundmodell. Hier lässt sich die Wellenausbreitung leicht behandeln und die anisotropen Effekte werden mit Hilfe der Perturbations-Methode berechnet. Um die jeder Perturbations-Methode anhaftenden Fehler zu minimieren, sollte das gewählte isotrope Hintergrundmedium dem korrektem anisotropen Medium so ähnlich wie möglich sein. Zur Bestimmung des optimalen isotropen Mediums wurden Formeln für sektoriell best angepasste isotrope Medien entwickelt. Deren Anwendung wurde anhand von Modellen mit transversal isotropen und orthorombischen Symmetrien gezeigt...
    Description: thesis
    Keywords: 551.22 ; 550 ; Seismische Wellen {Geophysik} ; Übertragungsmedien {Seismologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 134 S.
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  • 38
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.1 ; 550 ; VKA 150 ; TOO 000 ; Physikalische Petrologie ; Geothermik {Geophysik}
    Language: German
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  • 39
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 622.15 ; 552.5 ; 624.51 ; 550 ; VBP 800 ; TQJ 000 ; Ingenieurgeologie bei der unterirdischen Speicherung und Lagerung ; Geophysikalische Methoden in anderen Wissenschaftsgebieten
    Language: German
    Type: monograph , publishedVersion
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  • 40
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.5 ; 550 ; TUA 700 ; TVH 300 ; Verfahren zur Untersuchung der freien Atmosphäre {Meteorologie} ; Lufttemperatur {Meteorologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 153 S.
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  • 41
    Publication Date: 2021-03-29
    Description: With regard to geodesy optimizing procedures for nonlinear adjustment problems are presented. The procedures can be divided into local and global optimization techniques according to the type of the problem. If good initial values are given, the usage of local optimization techniques, (e.g., the Gauß-Newton procedure) is justified. If this is not the case, and the minimizing function has various local minimums, a global strategy must be implemented. Applying global optimization techniques one will not yield the global solution with certainty; only a probabilistic solution will be obtained. Nevertheless, combining local and global strategy and inclusion of all available a priori-information, a global optimizing system can be established that yields practical results for a wide area of problems. With the increase of the capacity of modern computers the efficiency of global optimization algorithms comes along ...
    Description: thesis
    Keywords: 526.9 ; 550 ; UND 000 ; Fehlertheorie {Praktische Geodäsie}
    Language: German
    Type: monograph , publishedVersion
    Format: 85 S.
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  • 42
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 622.15 ; 550 ; Elektrische Verfahren {Geophysik} ; Mitteleuropa {Geophysik}
    Language: German
    Type: monograph , publishedVersion
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  • 43
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.6 ; 550 ; TVF 000 ; TWB 000 ; TWH 100 ; Allgemeine Zirkulation der Atmosphäre {Meteorologie} ; Statistische Klimatologie und Klimatologische Modelle ; Einfluss der Verteilung von Land und Meer {Klimatologie}
    Language: German
    Type: monograph , publishedVersion
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  • 44
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.5 ; 550 ; EIGA 100 ; TVH 100
    Language: German
    Type: monograph , publishedVersion
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  • 45
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.701 ; 549 ; 550 ; VBN 500 ; Geochronologie einzelner Regionen im allgemeinen
    Language: German
    Type: monograph , publishedVersion
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  • 46
    Publication Date: 2021-03-29
    Description: Am Ausgangspunkt dieser Arbeit stand die Frage, ob und in welcher Form beim Bau der Autobahnen vor 1933 in Deutschland, Frankreich und Italien die Wahrnehmung von Landschaft' berücksichtigt wurde. Da die Diskussion um die veränderte Wahrnehmung von Landschaft' bei steigender Reisegeschwindigkeit erstmals intensiv im Zusammenhang mit dem Bau der Eisenbahnen im 19. Jahrhundert geführt wurde, leitet ein Rückblick auf diese Zeit die Arbeit ein. Hier konnte die historische Dimension des Untersuchungsthemas verdeutlicht sowie dessen wesentliche Diskussionspunkte aufzeigt werden, die - in modifizierter Form - ein knappes Jahrhundert später bei der Planung und beim Bau der Autobahnen erneut aufgegriffen wurden. Der italienische Futurismus wurde anschließend daraufhin untersucht, ob er neue Darstellungsformen für die veränderte Wahrnehmung von Landschaft' hervorgebracht hat. Das nachfolgende Kapitel diente dazu, die Bedeutung des Themas der Arbeit aufzuzeigen. Eine zusammenstellende Übersicht über den Status des Autobahnbaus und der Autobahnplanungen in Deutschland Frankreich und Italien vor 1933, die bis dato fehlte, wurde hier gegeben. Von zentraler Bedeutung war im Rahmen dieser Arbeit die Analyse der Gestaltungselemente ...
    Description: thesis
    Keywords: 944 ; QEB 000 ; Geographische Umweltwahrnehmung und Raumbewertung
    Language: German
    Type: monograph , publishedVersion
    Format: 307 S.
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  • 47
    Publication Date: 2021-03-29
    Description: The Aggregated Carbon Cycle, Atmospheric Chemistry, and Climate model (ACC2) (Tanaka and Kriegler et al., 2007a) describes physical-biogeochemical processes in the Earth system at a global-annual-mean level. Compared to its predecessors NICCS (Hooss, 2001) and ICM (Bruckner et al., 2003), ACC2 adopts more detailed parameterizations of atmospheric chemistry involving a set of agents (CO2, CH4, N2O, O3, SF6, 29 species of halocarbons, sulfate aerosols (direct effect), carbonaceous aerosols (direct effect), all aerosols (indirect effect), stratospheric H2O, OH, and pollutants NOx, CO, and VOC). In contrast to the Impulse Response Function (IRF) approaches in the predecessor models, ACC2 uses DOECLIM (Kriegler, 2005), a land-ocean Energy Balance Model (EBM), to calculate temperature change. The carbon cycle is described by box models based on the IRF approach. A temperature feedback is newly implemented to ocean and land CO2 uptake. The most novel aspect of ACC2 is its inverse estimation, the first attempt to estimate uncertain parameters simultaneously for the carbon cycle, atmospheric chemistry, and climate system by taking their interactions into account. Theoretical underpinning of the ACC2 inversion is the probabilistic inverse estimation theory (Tarantola, 2005), which characterizes the ACC2 inversion as an integration of the existing Earth system knowledge. This includes parameter estimates, observational databases, reconstructions, and physical-biogeochemical laws...
    Description: thesis
    Keywords: 551.5 ; TUA 500 ; TOY 000 ; TVA 200 ; VJD 000 ; Meteorologische Modelle ; Energiebilanzen in der Geodynamik {Geophysik} ; Zusammensetzung der Atmosphäre {Meteorologie} ; Geochemie der Atmosphäre
    Language: English
    Type: monograph , publishedVersion
    Format: 300 S.
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  • 48
    Publication Date: 2021-03-29
    Description: Durch den Prozess der Urbanisierung verändert die Menschheit die Erdoberfläche in großem Ausmaß und auf unwiederbringliche Weise. Die optische Fernerkundung ist eine Art der Erdbeobachtung, die das Verständnis dieses dynamischen Prozesses und seiner Auswirkungen erweitern kann. Die vorliegende Arbeit untersucht, inwiefern hyperspektrale Daten Informationen über Versiegelung liefern können, die der integrierten Analyse urbaner Mensch-Umwelt-Beziehungen dienen. Hierzu wird die Verarbeitungskette von Vorverarbeitung der Rohdaten bis zur Erstellung referenzierter Karten zu Landbedeckung und Versiegelung am Beispiel von Hyperspectral Mapper Daten von Berlin ganzheitlich untersucht. Die traditionelle Verarbeitungskette wird mehrmals erweitert bzw. abgewandelt. So wird die radiometrische Vorverarbeitung um die Normalisierung von Helligkeitsgradienten erweitert, welche durch die direktionellen Reflexionseigenschaften urbaner Oberflächen entstehen. Die Klassifikation in fünf spektral komplexe Landnutzungsklassen wird mit Support Vector Maschinen ohne zusätzliche Merkmalsextraktion oder Differenzierung von Subklassen durchgeführt...
    Description: thesis
    Keywords: 550.28 ; 622.159 ; 550 ; TQH 000 ; Aerogeophysik
    Language: English
    Type: monograph , publishedVersion
    Format: 276 S.
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  • 49
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; 550 ; TOD 400 ; TOE 000 ; TSB 000 ; Erdmantel {Geophysik} ; Physikalisches Verhalten der Erde {Geophysik} ; Mitteleuropa {Geophysik}
    Language: English
    Type: monograph , publishedVersion
    Format: 147 S.
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  • 50
    Publication Date: 2021-03-29
    Description: Aim of the study was to test the capability of multiple trace gas analyses for the assessment of regional carbon budgets. Therefore, air samples were taken by airborne and ground level activities during several field campaigns within Europe. Basic elements for the data acquisition were the development of an adapted sampling system and of an enhanced investigation strategy. By the study important processes like insufficient mixing and advection were identified which could seriously effect the measurements and thus the calculated budgets. The concluding results prompt for improvements regarding appropriate flux estimation techniques and application of the enhanced investigation strategy within a frame of combined measurement activities.
    Description: thesis
    Keywords: 551.5 ; 550 ; TUA 700 ; VJI 000 ; VJD 100 ; TVA 210 ; Verfahren zur Untersuchung der freien Atmosphäre {Meteorologie} ; Geochemische Kreislaufmodelle ; Geochemie der Ungestörten Atmosphäre ; Chemische Zusammensetzung der Atmosphäre {Meteorologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 344 S.
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  • 51
    Publication Date: 2021-03-29
    Description: The southeastern Mediterranean Sea and the northern section of Egypt constitutes one of the most complex tectonic areas in the Mediterranean. This study is an attempt to achieve a better understanding of tectonics, and geodynamical processes along a complex tectonization region. These include crustal structure, thickness of sediments, transition between oceanic and continental crust and regional integrated model of the gravity field observed. A wide range of field work from the geophysical data has been acquired and used in this study with respect to the gravity and magnetic data as well as the results of deep seismic soundings. A comparison between the marine gravity data and the gravity data derived from satellite altimetry was made to ensure that the marine gravity data compiled from different marine surveys were compatible...
    Description: thesis
    Keywords: 622.15 ; 551.1 ; 550 ; TSZ 100 ; VAE 880 ; TSZ 100 ; VAE 880 ; Atlantischer Ozean {Geophysik} ; Passive und aktive Kontinentalränder {Geologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 184 Bl.
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  • 52
    Publication Date: 2021-03-29
    Description: Die dynamische Entwicklung des neotektonisch und vulkanisch aktiven südchilenischen Plattenrandes wird durch die schiefe Subduktion der ozeanischen Nazca Platte unter den südamerikanischen Kontinent gesteuert. Die Deformationen in der Oberplatte sind von der Verformungsaufteilung (strain partitioning) des Konvergenzvektors in Bewegungen und Deformationen senkrecht und parallel zum Plattenrand sowie von diversen anderen in Wechselwirkung zueinander stehenden exogenen und endogenen Faktoren abhängig. Das Untersuchungsgebiet (Arauco-Bíobío Trench-Arc-System), das sich zwischen den Küstenstädten Concepción und Valdivia (36ʿ45`-40ʿS) und bis in den magmatischen Bogen an der chilenisch-argentinischen Grenze (73ʿ30`-71ʿW) erstreckt, bietet die Möglichkeit, die neogene Entwicklung eines Subduktionssystems zu studieren und die für die differenzierten Deformationen verantwortlichen Faktoren zu evaluieren. Mit Hilfe von detaillierten strukturgeologischen Untersuchungen der räumlichen und zeitlichen Zusammenhänge der andinen und auch prä-andinen Strukturen konnten kinematische Modelle für die verschiedenen Einheiten des Trench-Arc-Systems entwickelt werden. Tektonische Untersuchungsmethoden wurden durch die Analyse von Fernerkundungsdaten sowie geomorphologischen und sedimentologischen Studien ergänzt. Die neotektonische Aktivität wurde durch gängige paläoseismologische Beobachtungen,..
    Description: thesis
    Keywords: 550 ; TOH 800 ; VAE 880 ; TSX 500 ; VEX 500 ; Paläoerdbeben {Geophysik} ; Passive und aktive Kontinentalränder {Geologie} ; Chile {Geophysik} ; Chile {Geologie}
    Language: German
    Type: monograph , publishedVersion
    Format: 169 S.
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  • 53
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 910 ; QGJ 120 ; Teilfragen zu Indien {Geographie}
    Language: German
    Type: monograph , publishedVersion
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  • 54
    Publication Date: 2021-03-29
    Description: The search for extrasolar planets is a relatively new field in astronomical and astrophysical sciences that was boosted by the first discovery of the exoplanet 51 Peg b in 1995 by radial velocity measurements. The short orbital period of 4.2 days determined for this giant exoplanet encouraged the accelerated development of another search method due to the high probability that such a Hot Jupiter planet would cross its host star in the line of sight yielding a photometrically detectable signal during this crossing. This transit method (also known as the occultation or eclipse method) measures such a darkening signal as an evidence for an orbiting planet allowing the determination of the radius of the planet. Combined with the information obtained with radial velocity measurements the mass and the density of the planet can be calculated. This unique opportunity to study detailed physical properties of exoplanets is advantageous compared to planets proven only by other search methods. In this thesis the establishing of the new ground-based transit survey Berlin Exoplanet Search Telescope (BEST) is described. This system consists of a 20cm Schmidt telescope and a CCD camera covering a field of view (FOV) of 3.1ʿ x 3.1ʿ. The set-up and the successful implementation of the BEST system are described in this work. Furthermore the developed strategies for the photometric observations, the calibration and analysis of the data, follow-up observations and their optimization are commented. During the 2-year observational campaign (2001-2003) from the Thüringer Landessternwarte (TLS) Tautenburg, Germany, three target fields were observed for 90 nights ...
    Description: thesis
    Keywords: 523 ; THX 100 ; Detektionsmethoden {Astronomie: Extrasolare Planetensysteme}
    Language: English
    Type: monograph , publishedVersion
    Format: 269 S.
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  • 55
    Publication Date: 2021-03-29
    Description: Context Extragalactic absorbers with column densities exceeding NH I 〉 2 × 1020 hydrogen atoms cm-2 are generally termed damped Ly alpha (DLA) systems. The absorbers are basically comprised of predominantly neutral gas, which is an essential prerequisite for the formation of stars. The spectroscopy of absorbers offers the best possibility to study the chemical composition of the supposed equivalents of the interstellar medium of local galaxies at an earlier stage of cosmic evolution. Absorbers in the sub-DLA range with NH I 〉 1019 cm-2 may consist of predominantly neutral gas, if the cosmic UV background is reduced...
    Description: thesis
    Keywords: 523 ; TII 040 ; Physikalische Eigenschaften {Astronomie: Interstellare Materie}
    Language: English
    Type: monograph , publishedVersion
    Format: 68 S.
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  • 56
    Publication Date: 2021-03-29
    Description: With the last generation of X-ray satellites, such as XMM-Newton and Chandra, our knowledge about the X-ray properties of Active Galactic Nuclei (AGN) has greatly improved. Detailed spectroscopy and long-term observations of hundreds of kilo-seconds have provided new insights into the mechanisms of X-ray production, its modification by intervening matter, and X-ray variability. In this thesis I present radiative transfer modeling of AGN in the Far-UV and X-ray range. The modeling considers several aspects of the observed X-ray properties: the Compton reflection/reprocessed component, X-ray variability and flares, and the effects of the warm absorber. For the X-ray reprocessing, I investigate in detail the magnetic flare model assuming solar-like magnetic reconnections above the accretion disk
    Description: thesis
    Keywords: 523 ; TEG 440 ; TBK 000 ; Schwarze Löcher {Astronomie: Kosmogonie} ; Hochenergieastronomie
    Language: English
    Type: monograph , publishedVersion
    Format: 151 S.
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  • 57
    Publication Date: 2021-03-29
    Description: PHOENIX has been used to calculate model atmospheres of classical novae in the X-ray spectral range. The models account for an expanding, one-dimensional spherically symmetric medium in full non-local thermodynamic equilibrium. Nova atmospheres have been modeled with PHOENIX since the early 90's to fit the early nova spectra in the ultraviolet and infrared spectral ranges. In this work the PHOENIX-code has been enhanced to also model X-ray spectra. This was accomplished by accounting for atomic data and physical processes. The synthetic spectra were compared to observations from the LETGS onboard the CHANDRA X-ray satellite. The template is the observation of nova V4743 Sagittarii in March 2003. The spectrum is very spectacular because of the nova brightness and CHANDRA's spectral resolution. Further observations from July2003, September 2003, and February 2004 were taken. Models with solar and non-solar abundances have been calculated and the synthetic spectra have been fitted to the four observations. The fits were used to discuss discrepancies between models and observations. The effective temperature of the atmosphere, the hydrogen column density, and the abundances ofhelium, carbon, nitrogen, oxygen, and iron in the shell were determined by the fits. It was examined how the parameters evolve with time. With the models the atmosphere structure and NLTE effects were determined. The models were compared to the previous nova model atmospheres from PHOENIX ...
    Description: thesis
    Keywords: 523 ; THU 155 ; THN 400 ; Eruptionsveränderliche {Astronomie: Sterne} ; Sternatmosphären {Astronomie}
    Language: English
    Type: monograph , publishedVersion
    Format: 196 S.
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  • 58
    Publication Date: 2021-03-29
    Description: Optical counterparts of X-ray selected sources to a large part consist of active galactic nuclei (AGN). A large proportion of these counterparts turns out to be optically variable, and because the timescales and manner of this variability can give important clues regarding the physical nature and structure of the counterparts, searching for variable AGN is a worthwhile undertaking. In order to perform such an optical variability survey, a subset of 167 X-ray sources in an area around the NEP was selected in this work from the X-ray catalogues derived from the ROSAT all-sky survey (RASS). Contemporaneous optical observations were available from a collaboration with the Karl-Schwarzschildt observatory (KSO) Tautenburg. A total of 89 plates were analyzed, covering an area of 35 degrees square around the NEP and spanning a timebase of 30 month ...
    Description: thesis
    Keywords: 523 ; TBK 000 ; TC 200 ; Hochenergieastronomie ; Astronomische Beobachtungen vom Weltraum aus
    Language: English
    Type: monograph , publishedVersion
    Format: 283 S.
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  • 59
    Publication Date: 2021-03-29
    Description: The Sun shows a variety of transient surface features which are summarized as solar activity. Activity phenomena, apparently similar to the solar case, are also observed on stars other than the Sun. Stellar activity is closely related to magneto-hydrodynamic processes in a stars̉ convection zone. A dynamo is believed to operate in the outer convection zone of solar-like stars, generating magnetic fields by complex motions of the convecting plasma under the influence of rotation. Differential (i.e. non-rigid) rotation of the stellar surface is an important indicator of the overall dynamics of a stars̉ outer convection zone. Sunspots are a conspicuous token of solar activity; dark spots can also be observed on the surface of stars other than the Sun. To which degree starspots are analogues of sunspots is presently only poorly known; the processes governing their lifetime and structure are largely unexplored. Doppler imaging overcomes the diffraction-limitations of direct and interferometric imaging techniques by making use of information that is modulated into a star’s spectrum due to its rotation. Doppler imaging is currently the only method to produce well-resolved images of solar-like stars. After a selective review of the observational and theoretical foundation,
    Description: thesis
    Keywords: 523 ; THN 400 ; THE 400 ; Sternatmosphären {Astronomie} ; Rotation, Eigenbewegung {Astronomie: Sterne}
    Language: English
    Type: monograph , publishedVersion
    Format: 187 S.
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  • 60
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 549 ; VGF 200 ; VHB 830 ; Phasengleichgewichte und Umbildungen {Mineralogie} ; Gruppensilikate {Mineralogie}
    Language: German
    Type: monograph , publishedVersion
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  • 61
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.9 ; VOBC 700 ; VBQ 400 ; Transportvorgänge in Böden ; Grundwassergefährdung {Hydrogeologie}
    Language: German
    Type: monograph , publishedVersion
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  • 62
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.9 ; VJF 000 ; VJC 400 ; VEB 217 ; Umweltgeochemie insgesamt ; Fluid-Gestein-Wechselwirkungen {Geochemie} ; Sachsen {Geologie}
    Language: German
    Type: monograph , publishedVersion
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  • 63
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; VAE 850 ; VAE 400 ; VDE 000 ; VEO 170 ; Festländische Lineamente {Geologie} ; Tektogenese {Geologie} ; Proterozoikum ; Sudan {Geologie}
    Language: English
    Type: monograph , publishedVersion
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  • 64
    Publication Date: 2021-03-29
    Description: In der vorliegenden Arbeit wurde untersucht, welche Parameter die Anwendbarkeit der Geothermometer für Wasserstoff, im System Wasserstoff/ Methan/ Wasser, und Kohlenstoff, im System Methan/ Kohlendioxid, bestimmen. Dazu wurden die Hydrothermalsysteme Turtle Pits, Red Lion, Comfortless Cove, Wideawake, Lilliput, Nibelungen und Logatchev untersucht. Analysen der Wassersäule zeigten hydrothermale Prägung, wie erhöhte Konzentration von Wasserstoff und Methan, sowie eine erhöhte Trübe des Seewassers bei schwarzen Rauchern. Diese Untersuchungen führten auch zur Entdeckung des südlichsten bekannten Hydrothermalfeldes im Atlantik, dem Lilliputfeld. Es wurden Messungen der Konzentration und der Isotopensignatur von Wasserstoff und Methan durchgeführt. Die Hydrothermalsysteme wurden zusätzlich mit Hilfe von weiteren fluidchemischen Daten und geologischen Eigenschaften der Quellen charakterisiert. Aus den Isotopendaten konnte mit Hilfe der Gleichung für die isotopische Gleichgewichtsfraktionierung eine apparente Isotopentemperatur berechnet werden. Es wurde untersucht inwieweit diese apparente Temperatur den realen Temperaturen in den Hydrothermalsystemen entspricht. Beim Wasserstoffthermometer konnte eine gute Vereinbarkeit mit der Austrittstemperatur fokussierter Quellen festgestellt werden. Für diffuse Quellen gilt dies jedoch nicht, da bei diesen häufg eine Vermischung mit Seewasser unterhalb des Meeresbodens stattfindet ...
    Description: thesis
    Keywords: 550 ; TQF 000 ; VGF 400 ; TSZ 100 ; VEZ 100 ; Geothermische Verfahren {Geophysik} ; Druck- und Temperaturbestimmungen {Mineralogie} ; Atlantischer Ozean {Geophysik} ; Atlantischer Ozean {Geologie}
    Language: German
    Type: monograph , publishedVersion
    Format: 116 S.
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  • 65
    Publication Date: 2021-03-29
    Description: Reflection seismic is one of the most commonly used geophysical method for the oil and gas exploration. In this thesis I show the application of the Common Reflection Surface (CRS) stack technique to improve the quality of reflection seismic images. Conventional seismic imaging method based on the CMP stacking does not use the full potential of the dataset due to reflection point dispersal in the presence of dipping reflectors or laterally inhomogeneous media. Application of the CRS stack technique is advantageous in complex areas, since it involves information about the shape of seismic reflectors, i.e., dip and curvature, into processing. Moreover, a multiparameter formula allows to sum up more traces during the stack. All together, this leads to better imaging results, especially to an improvement of the signal-to-noise (S/N) ratio. Reflection events in the CRS stack sections appear clearer and more continuous compared to conventional CMP stack sections...
    Description: thesis
    Keywords: 622.15 ; TQC 220 ; VRE 110 ; Reflexionsseismik {Geophysik} ; Geophysikalische Verfahren
    Language: English
    Type: monograph , publishedVersion
    Format: 129 S.
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  • 66
    Publication Date: 2021-03-29
    Description: Interpretation of high and very high resolution reflection seismic data from the western Black Sea shelf yielded a seismic stratigraphic model of the Late Quaternary deposits on the southwestern Black Sea shelf. This model was combined with borehole information to carry out a regional subsidence analysis, so that the influence of tectonics and sediment compaction could be ruled out in the estimation of sea-level changes in the Black Sea. Mio-Pliocene sediments form the baseline of the interpretation. On top of it four Quaternary seismic stratigraphic units were identified on the western Black Sea shelf; they are named in chronological order Unit 4 to Unit 1 (U4 U1). Pliocene deposits are built up by gently basinward dipping layers of relatively high and approximately uniform thickness. Buried graben structures attest to the influence of extensional tectonics until the Upper Pliocene. Later, strong erosion left a rugged surface on the inner and middle shelf that was later overlain by a thin layer of Quaternary to Holocene sediments. The Pliocene is followed by the oldest observed Quaternary seismic sequence (Unit 4, U4); it comprises layers of Lower Quaternary age that dip towards the basin at a steeper angle than those of the Pliocene. Within U4 the oldest of three Quaternary shelfedge delta systems in the study area was found, that supposedly marks an Early Quaternary sea-level lowstand...
    Description: thesis
    Keywords: 551 ; 551 ; 550 ; VDI 200 ; VEZ 120 ; TSZ 100 ; Quartär ; Randmeere {Geologie} ; Atlantischer Ozean {Geophysik}
    Language: English
    Type: monograph , publishedVersion
    Format: 170 S.
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  • 67
    Publication Date: 2021-03-29
    Description: For seismic imaging of complex 3-D structures by e.g. prestack Kirchhoff depth migration large amounts of traveltime tables are required. This work provides a wavefront-oriented ray tracing technique for multi-valued traveltimes in smooth 3-D heterogeneous anisotropic media. In this method, wavefronts are propagated stepwise through the model and output quantities are interpolate (e.g., traveltimes, slowness) from rays to gridpoints. In contrast to isotropic media, where the input is a velocity model, the model for an anisotropic medium is defined by 21 elastic parameters at each gridpoint. To provide an efficient, accurate and fast algorithm for the interpolation of the elastic parameters to arbitrary points, the Cardinal Spline interpolation has been used, which produces an interpolated function that is continuous through the second derivative. The insertion of a new ray is performed by tracing it directly from the source. To calculate traveltimes at gridpoints a distance-weighted averaging method is used. To demonstrate the accuracy of the method the traveltimes computed for a homogeneous anisotropic model with elliptical symmetry are compared to exact traveltimes available for this medium. Since it exists no analytical solution for an inhomogeneous anisotropic model, I compare the results with an alternative method for traveltime computation, the FD perturbation method...
    Description: thesis
    Keywords: 622.1592 ; 550 ; TQC 200 ; Prospektionsseismik {Geophysik}
    Language: English
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  • 68
    Publication Date: 2021-03-29
    Description: To understand processes and dynamics linked to the volumetric water content of soils thorough knowledge of the water distribution inside soils is required. The applicability of the georadar technique for small scale soil heterogeneity mapping and monitoring is investigated using four different methods. Since the uppermost meter of the soil lacks a sufficient amount of spacious reflectors no standard georadar methods can supply adequate coverage of the investigated area under field conditions. Therefore four methods were evaluated to present an assortment of the most promising methods for different case specific problems. Owing to the averaging nature of the georadar technique the introduced methods needed to be adapted to small scale investigations. Based on numerical simulations and concise measurements new processing procedures are applied to achieve the required spatial resolution of less than 0.3 m. All four methods were successfully applied during realistic field measurement conditions. The transmission method is applied to a soil column experiment filled with undisturbed natural soil. In the course of an irrigation experiment the infiltration of the water front as well as the water dynamics afterwards were reproduced. The application of georadar transmission tomography provided spatial allocatable water content distributions over the time of the water seepage with spatial accuracies of approximately 0.1 m and a temporal resolution of approximately 30 min...
    Description: thesis
    Keywords: 551.48 ; 550.28 ; 550 ; TQD 800 ; Georadar {Geophysik}
    Language: English
    Type: monograph , publishedVersion
    Format: 146 S.
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  • 69
    Publication Date: 2021-03-29
    Description: Im Rahmen verschiedener Drittelmittelprojekte waren vom Autor Wechselstrommessungen bei z.T. sehr kleinen Signal- zu Rauschverhältnissen durchzuführen. In den ariden Messgebieten (Ägypten, Sudan) waren hierfür die schlechten Ankopplungsbedingungen verantwortlich, in den dicht besiedelten Gebieten (Stadtgebiet Berlin) die hohen Störspannungspegel. Trotz konsequenter Anwendung von Filter- und Stapelungstechniken, blieb die Datenqualität bisweilen unakzeptabel niedrig. Inspiriert durch multivariate Zeitreihenanalysentechniken der Audiomagnetotellurik wurde vom Autor eine geoelektrische Referenztechnik mathematisch formuliert und mit Hilfe von speziell hierfür gefertigten mehrkanaligen Geoelektrikapparaturen erfolgreich eingesetzt. Anhand von Fallbeispielen wurde demonstriert, dass die Anwendung der geoelektrischen Referenztechnik den statistischen Messfehler sowohl im Gelände als auch im Labor um bis zu 2 Größenordnungen verringern kann. Anders als Stapelungstechniken vermindert die Referenztechnik den Messfortschritt jedoch nicht. Ein ungünstig gewählter Referenzstationsstandort kann zu systematisch verfälschten Messwerten führen. Anhand von Modellrechnungen wurde untersucht welche Anordnungen vorteilhaft sind...
    Description: thesis
    Keywords: 537 ; 550 ; TQD 000
    Language: German
    Type: monograph , publishedVersion
    Format: 325 S.
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  • 70
    Publication Date: 2021-03-29
    Description: Organotin compounds are variously used industrial chemicals. One of the most toxicological relevant compounds is tributyltin (TBT). TBT has been used as an effective component in antifouling paints for decades. Thus, it is set free into the water column in considerable amounts and affects also non-target organismens in very low concentrations. Molluscs like snails and mussels are particularly sensitive and reproduction can be influenced significantly thereby. Once released into the water column, TBT accumulates in sediments and will remain there beyond years due to its high persistence. Several guideline values, target levels and quality standards were specified for TBT, its degradation products monobutyltin (MBT) and dibutyltin (DBT) as well as for other organotin compounds in sediments...
    Description: thesis
    Keywords: 551.9 ; VJF 000 ; Umweltgeochemie insgesamt
    Language: German
    Type: monograph , publishedVersion
    Format: 214 S.
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  • 71
    Publication Date: 2021-03-29
    Description: Merapi volcano in Central Java, Indonesia, is considered one of the most dangerous volcanoes worldwide. Due to the high viscosity of its magma, the lava emerging at the top the volcano cannot flow silently down the flanks of the volcano but builds a lava dome. An indicator for the stability of the lava dome are rockfalls and block and ash flows, which are caused by local instabilities at the dome. When the lava dome reaches a critical size, it collapses. This results in dangerous block and ash flows, which can reach several kilometers into the proximity of the volcano. In the past rockfall and block and ash flow activity has been observed visually or by seismic networks. However, visual observations are often impossible due to bad visibility conditions and until now seismic measurements allow only few insights into the dynamic processes that are involved in instability events, i.e. events of material breaks off the lava dome. In order to enhance monitoring of lava dome activity, a first prototype Doppler radar system has been installed at the western of the Merapi in October 2001. This system consists of a frequency modulated continuous wave (FMCW) 24GHz Doppler radar. The Doppler spectra recorded by the system give a relative measure of the amount of material moving through the beam as well as information about its velocities. Because the radar system is insensitive for clouds, the system provides first continuous "quasi-visual" observations of dome instabilities...
    Description: thesis
    Keywords: 551.21 ; TQD 800 ; TSJ 300 ; VAD 700 ; VAD 100 ; TSJ 300 ; VAD 700 ; VAD 100 ; Indonesien {Geophysik} ; Regionaler Vulkanismus {Geologie} ; Methodik in der Vulkanologie {Geologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 156 S.
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  • 72
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: In this thesis, the 1997 Vogtland/NW-Bohemia swarm has been selected for the analysis of inhomogeneities in the stress field because two predominant nearly perpendicular flat zones of seismicity are visible in the hypocentre distribution implying inhomogeneities in the stress field. This is unusual compared to other swarms originating from this area. An existing dataset of waveform data, P- and S-phase picks, and master event locations has been analysed regarding similarity of waveforms, location refinement, and estimation of relative moment tensors. The latter are used together with a regional dataset of 50 single focal mechanisms and 125 focal mechanisms from the 2000 hydraulic fracturing experiment at the KTB for an estimate of the regional homogeneous and the locally inhomogeneous stress field. An automated processing procedure consisting of coherence analysis,precise relocation, relative moment tensor inversion, and stress trajectory determination has been set up. The coherence analysis has been successfully applied using a new method that uses three component seismograms. 457 events are separated into 13 multiplets of similar waveforms of at least size 8. Another result are precise relative arrival time measurements which are fed into the precise relocation program "hypoDD". Two nearly perpendicular structures are found in the hypocentre distribution. 352 moment tensors are estimated using a relative moment tensor inversion. Three different algorithms to distinguish between fault plane and auxiliary plane are successfully applied to them...
    Description: thesis
    Keywords: 551.22 ; 550 ; VAE 130 ; TOH 400 ; Geomechanik ; Übertragungsmedien {Seismologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 184 S.
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  • 73
    Publication Date: 2021-03-29
    Description: Mittelozeanische Rücken finden sich in allen größeren Ozeanbecken der Erde. Sie besitzen die weltweit höchste Produktionsrate an Extrusiv- und Intrusivgesteinen. Bildung ozeanischer Kruste und Vulkanismus an divergenten Plattengrenzen sind fundamentale Prozesse, deren Grundverständnis wichtig ist. Magmatische Dykes bauen einen Großteil ozeanischer Kruste auf. Ihr Vorkommen ist besonders augenfällig im sogenannten Sheeted-Dyke-Komplex der oberen Kruste. In dieser Arbeit wird die Wechselwirkung zwischen Magmakammern und Dykes aufgrund von Spannungsfeldern untersucht. Die Ergebnisse werden zur Analyse ozeanischer Krustenbildung im allgemeinen und des Sheeted-Dyke-Komplexes im besonderen benutzt. Da nur wenig Daten über die Geologie mittelozeanischer Rücken und den Verlauf magmatischer Prozesse verfügbar sind und analytische Modelle zumeist an der Berücksichtigung inhomogener Medien und heterogener Spannungsfelder scheitern, stellen numerische Modelle ein wichtiges Werkzeug zur weiteren Erforschung dieser Abläufe dar. Um den Aufstieg von Dykes als Fortbewegung fluidgefüllter Risse zu berechnen, wurde eine Randelementmethode verwendet. Modelle für den Magmaaufstieg im Mantel müssen sowohl die hohen Transportgeschwindigkeiten als auch die Trennung von Schmelze und Mantelgestein zur Verhinderung chemischer Ausgleichsreaktionen und die Fokussierung des Magmas von der breiten Schmelzzone in der Tiefe zur schmalen Austrittszone an der Rückenachse leisten...
    Description: thesis
    Keywords: 551.1 ; 550.28 ; 550 ; VAE 130 ; VAE 890 ; TSZ 000 ; Geomechanik ; Ozeanische Kruste {Tektonik} ; Meeresräume {Geophysik}
    Language: English
    Type: monograph , publishedVersion
    Format: 178 S.
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  • 74
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 622.15 ; 553.28 ; 550 ; TSI 000 ; VRE 160 ; VSI 000 ; TSI 000 ; VRE 160 ; VSI 000 ; Vorderasien {Geophysik} ; Regionale Exploration und Prospektion {Kohlenwasserstofflagerstätten} ; Vorderasien {Fossile Energieträger}
    Language: English
    Type: monograph , publishedVersion
    Format: 93 Bl.
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  • 75
    Publication Date: 2021-03-29
    Description: In this thesis, I propose several methods for an efficient computation of 2D and 3D traveltimes of transmitted waves in smooth media. Traveltimes are needed in several seismic processing methods such as Kirchhoff prestack and poststack migration, migration velocity analysis, Kirchhoff modelling, or traveltime tomography. The greatest number of traveltimes are needed by 3D prestack Kirchhoff depth migration (PKDM). Despite the continuous increase in computing capacities, the computation of traveltimes for 3D PKDM is still a challenge. Since the wavefront is usually folded, the same wave may arrive at a subsurface point more than one time, i.e., we have multivalued traveltimes...
    Description: thesis
    Keywords: 551.22 ; 550
    Language: German
    Type: monograph , publishedVersion
    Format: 126 S.
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  • 76
    facet.materialart.
    Unknown
    Univ. Berlin
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 550.28 ; 550 ; VBH 000 ; VBH 000 ; Fernerkundung
    Language: English
    Type: monograph , publishedVersion
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  • 77
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.22 ; 550 ; TQC 100 ; Physikalische und mathematische Grundlagen {Geophysik: Seismik}
    Language: English
    Type: monograph , publishedVersion
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  • 78
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 622.15 ; 551.1 ; 550 ; TQG 000 ; TOO 000 ; TOD 410 ; TSV 000 ; TSZ 300 ; TQG 000 ; TOO 000 ; TOD 410 ; TSV 000 ; TSZ 300 ; Geophysikalische Bohrlochmessungen ; Geothermik {Geophysik} ; Oberer Erdmantel {Geophysik} ; Nordamerika {Geophysik} ; Pazifischer Ozean {Geophysik}
    Language: German
    Type: monograph , publishedVersion
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  • 79
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551.701 ; 549 ; VBN 200 ; VHC 200 ; VBN 200 ; VHC 200 ; Radiometrische Altersbestimmung ; Schwerminerale
    Language: English
    Type: monograph , publishedVersion
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  • 80
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 551 ; VAE 840 ; VEO 170 ; Rifts {Geologie} ; Sudan {Geologie}
    Language: German
    Type: monograph , publishedVersion
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  • 81
    Publication Date: 2021-03-29
    Description: During several marine geophysical data acquisition cruises in the western Baltic Sea, for the Baltseis and NeoBaltic projects, a dense grid of 2D high-resolution multichannel seismics and to some extend gravity and magnetic data were acquired in the German and Danish territorial waters of the region. The western Baltic Sea comprises the northern part of the Northeast German Basin on the southern flank of the Ringkøbing-Fyn High. Furthermore, parts of the suture zone between the Avalonia and Baltica plates (the Caledonian Deformation Front) and the Sorgenfrei Tornquist Zone were investigated during these research cruises. Adjacent to the study area two structures are located, which are important for the structural evolution in the region. To the west the N-S trending Glückstadt Graben and in the eastern part the E-W running Grimmen High...
    Description: thesis
    Keywords: 550 ; VBM 000 ; VAE 820 ; TSB 000 ; VEB 110 ; TQC 200 ; Geologische Interpretation geophysikalischer Beobachtungen ; Sedimentationsbecken als Erdkrustentypen {Geologie} ; Mitteleuropa {Geophysik} ; Norddeutsche Senke {Geologie} ; Prospektionsseismik {Geophysik}
    Language: English
    Type: monograph , publishedVersion
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  • 82
    Publication Date: 2021-03-29
    Description: Zu einem aktuellen Thema der Geodäsie werden in Form geeigneter Berechnungsverfahren im Spektralbereich wie auch im Zeitbereich Auswertestrategien zur Bestimmung globaler Erdschwerefeldmodelle anhand von Satellitenbeobachtungsdaten diskutiert. Die praktische Aufgabenstellung zur Bewältigung solcher hochgenauer, automatisierter Messtechniken erfordert ein allgemeines Lösungskonzept mittels dem irregulär verteilte, heterogene Messdaten über ein theoretisch einwandfreies Verfahren miteinander verknüpft werden können. Zur Bildung der Normalgleichungssysteme im Sinne einer Ausgleichung mit voller Korrelation müssen dazu die Beobachtungspositionen anhand der Kugelfunktionen integriert werden. Durch die Zerlegung der Kugelfunktionen in deren spektrale Basisfunktionen lässt sich der notwendige Arbeitsaufwand in zwei grundlegende Arbeitsschritte aufteilen, einmal in Abhängigkeit von der Anzahl der Daten und einmal Abhängig von der Grösse des Rechenmodelles. Die Integration der Daten kann daher im ersten Schritt äusserst effizient vollzogen werden, während die daran anschliessende Berechnung der Normalgleichungen und deren Inversion in Abhängigkeit von der jeweiligen Auflösung als konstant zu betrachten ist...
    Description: thesis
    Keywords: 526.7 ; 550.28 ; 622.15 ; 550 ; TQA 000 ; Gravimetrische Verfahren {Geophysik}
    Language: German
    Type: monograph , publishedVersion
    Format: 123 S.
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  • 83
    Publication Date: 2021-03-29
    Description: In dieser Arbeit werden zwei mesoskopische Systeme untersucht, zum ersten die ferroelastischen Domänen in Calcium-dotiertem Bleiphosphat, zum zweiten die oszillatorische Biomineralisation im Calcit und Aragonit von Molluskenschalen. Beide Systeme weisen trotz ihrer offensichtlichen Verschiedenheit wesentliche Gemeinsamkeiten auf, da mesoskopische Strukturen ihren Aufbau bestimmen und somit ihre Eigenschaften beeinflussen. In dieser Arbeit wird gezeigt, daß sich Verunreinigungen durch Fremdatome in den untersuchten Materialien stets in den mesoskopischen Wandstrukturen anreichern. Domänenstrukturen werden bereits seit Jahrzehnten erforscht, über ihre Transporteigenschaften und ihr PoƯtential als chemische Mikrostrukturen wird jedoch erst in neueren Arbeiten berichtet. Die Topographie und die elektrische Leitfähigkeit der Domänenwände sowie des Bulk-Materials von Calcium-dotiertem Bleiphosphat und reinem Bleiphosphat wurde mit Hilfe eines modifizierten Rasterkraftmikroskops (CAFM) studiert. Der Leitfähigkeitsunterschied zwischen Wänden und Bulk beträgt etwa 7% für dotiertes Bleiphosphat, während für undotiertes Referenzmaterial kein Unterschied nachweisbar ist. Die Leitfähigkeit der dotierten Domänenwände erwies sich als vermindert...
    Description: thesis
    Keywords: 549 ; 551.1 ; TOR 000 ; VGD 000 ; Erdelektrizität {Geophysik} ; Mineralphysik
    Language: German
    Type: monograph , publishedVersion
    Format: 89 S.
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  • 84
    Publication Date: 2021-03-29
    Description: In this study different full waveform techniques was developed for the investigation of seismic ocean bottom single station data. These techniques were applied to data obtained in a pilot ocean bottom experiment in the Tyrrhenian Sea/Italy (TySea experiment) from December 2000 to May 2001. A network of broadband seven ocean bottom seismometers and seven ocean bottom hydrophones was installed above the subducting Ionian plate which descends from Southeast to Northwest. Local and teleseismic earthquakes were recorded by the stations. The newly developed techniques produce very promising results in reconstructing the sea floor structure beneath the stations and in attenuating waveform effects generated by water layer multiples. Additionally the techniques offer a possibility to determine the orientation of free fall ocean bottom seismometers. The main results are: 1. The waveform recorded at the seafloor differs from waveforms recorded at land stations. This is primarily due to multiple reflections in the water layer. These multiple reflections show different patterns on seismometer and hydrophone recordings depending on the seafloor structure. This opens the possibility to constrain the P-wave velocity structure beneath the station by means of a full waveform inversion...
    Description: thesis
    Keywords: 550 ; TSZ 100 ; VAE 890 ; TQC 700 ; Atlantischer Ozean {Geophysik} ; Ozeanische Kruste {Tektonik} ; Seismische Verfahren zur Feststellung von Atomexplosionen {Geophysik}
    Language: English
    Type: monograph , publishedVersion
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  • 85
    Publication Date: 2021-03-29
    Description: This work presents multichannel seismic and hydroacoustic data of four survey areas along the Red Sea Rift and the Dead Sea Transform Fault. Sedimentary Basins that developed due to the rifting of the Red Sea and the strike-slip displacement of the Dead Sea Transform Fault were investigated and models for their evolution were derived. The Red Sea Rift and the Dead Sea Transform Fault are the main tectonic features in the Middle East. The rifting process of the Red Sea that initiated in the late Oligocene and early Miocene separated the African Plate from the Arabian Plate. In the Middle Miocene, the extension was compensated in the northern part of the Red Sea with the initiation of the left lateral Dead Sea Transform Fault. Along the Red Sea, different stages of evolution can be observed. Whereas the southern part comprises already seafloor spreading, the northern part is assumed to be in the late stage of continental rifting. Because of huge evaporitic sediment layers within the entire Red Sea, direct basement observations are sparse. Surficial features like ocean deeps along the axis of the Red Sea are interpreted as first seafloor spreading cells in the transition process between seafloor spreading and continental rifting. Along the Dead Sea Transform Fault, 105 km of left lateral displacement are observed within the last 20 Ma. The displacement is most likely not continuous since its onset. The Dead Sea Transform Fault may have experienced a break in its history before 5 Ma...
    Description: thesis
    Keywords: 622.15 ; 551.8 ; 550 ; TSI 000 ; VAE 840 ; TSI 000 ; VAE 840 ; Vorderasien {Geophysik} ; Rifts {Geologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 127 S.
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  • 86
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: The purpose of the first part of this dissertation was to develop a migration algorithm for converted waves, and a tomographic method for estimating an interval shear wave velocity model. The developed algorithm is based on the Kirchhoff formalism. The elastic Kirchhoff integral and its implementation were discussed and summarised in Chapter 2. The derived migration integral was generalised for all types of multicomponent data. For practical reasons, multicomponent data are decomposed into their corresponding components (z,x, and y components), and the migration is performed separately for each component. Normally it is assumed that the decomposed wave components are free from other wave types. The migration result of each component shows particular characteristics of the subsurface. For example, PS data give the shear wave characteristics of the subsurface...
    Description: thesis
    Keywords: Reflexionsseismik {Geophysik} ; 622.15 ; 550 ; TQC 220
    Language: English
    Type: monograph , publishedVersion
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  • 87
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 522 ; TCE 320 ; Photometer, Polarimeter, spektroskopische Instrumente {Astronomische Instrumente}
    Language: German
    Type: monograph , publishedVersion
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  • 88
    Publication Date: 2021-03-29
    Description: This work presents the first three-dimensional gravity and magnetic investigation along the convergent Peruvian margin. Three-dimensional magnetic modelling is still a relatively untried and challenging technique. The gravity and magnetic models image nearly the whole margin which has been only partly resolved with geophysical methods up to now. The gravity and magnetic models are constructed for three areas between 7.25ʿS and 16.75ʿS and are based on the available wide-angle seismic velocity models (Hampel et al., 2002a; Broser et al., 2002). The continental margin is characterised by positive free-air anomalies of varying amplitudes, indicating that the margin has been shaped by the subduction of different features on the Nazca Plate...
    Description: thesis
    Keywords: 551.1 ; 622.15 ; 550 ; TSX 800 ; TQA 000 ; TQB 000 ; VAE 880 ; VEX 800 ; Peru und Ecuador {Geophysik} ; Gravimetrische Verfahren {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Passive und aktive Kontinentalränder {Geologie} ; Peru und Ecuador {Geologie}
    Language: English
    Type: monograph , publishedVersion
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  • 89
    facet.materialart.
    Unknown
    Univ. Hamburg
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 525.35 ; 551.1 ; 550 ; TOB 100 ; TOB 100 ; Drehbewegungen {Geophysik: Erde}
    Language: German
    Type: monograph , publishedVersion
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  • 90
    Publication Date: 2021-03-29
    Description: thesis
    Keywords: 910 ; QBD 700 ; QER 800 ; QBD 700 ; QER 800 ; Geoinformationssysteme {Geographie} ; Verkehrsgeographie {Wirtschaftsgeographie}
    Language: English
    Type: monograph , publishedVersion
    Format: 131 S.
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