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  • Ein temperaturabhängiges thermodynamisches Modell für das System H+ - NH_hn+4 - Na+ - SO2 -4 - NO-1hn3 - Cl- - H2O
    0000 0001 3139 F Dateiname Friese2008 pdf PDF 3 1 MB Google View Download Kategorien Thermodynamische Prozesse Verteilungskoeffizienten Physikalische Geochemie Zur Langanzeige Zusammenfassung Atmosphärische Aerosolpartikel spielen eine bedeutende Rolle in verschiedenen Fragestellungen der Luftreinhaltung Einen wesentlichen Bestandteil ihrer Masse bilden anorganische Komponenten wie Sulfat Ammonium und Nitrat die in der maritimen planetaren Grenzschicht u a durch Natrium und Chlorid ergänzt werden Die Wirkung eines Aerosols ist vom Phasenzustand der Partikel

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3139-F (2016-02-15)
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  • Behaviour of tiang tongkat foundation over Pontianak soft organic soil using 3D-finite element analysis
    386 Erstveröffentlichung 2008 Doktorarbeit Verlagsversion Englisch Zum Verlinken Bookmarken http hdl handle net 11858 00 1735 0000 0001 330E 1 Dateiname 386 pdf PDF 2 9 MB Google View Download Kategorien Bodenmechanik Erdbaumechanik Baugrunddynamik Zur Langanzeige Zusammenfassung Peat deposits are distributed mostly along the coast of West Kalimantan Indonesia particularly in and around the provincial capital of Pontianak There are many problems with constructing over peat soil as the existence of this type of soil always generates geotechnical engineering problems for regional development For light construction on peat land several variations of Indonesian traditional floating wood foundations commonly called tiang tongkat foundations are still being used today A tiang tongkat foundation of any dimension is constructed over different fields The foundation was modelled as three dimensional linear elastic and the Pontianak soft organic soil was modelled as undrained Soft Soil Creep Model All of the 324 models were made to be used for simulation by means of the Plaxis 3 Dimensional Foundation Program The purpose of this analysis is to predict the load settlement behaviour and the capacity of traditional foundations The comparison between field tests and numerical analysis and analytical solutions are also demonstrated Share on Das Dokument erscheint

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-330E-1 (2016-02-15)
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  • The effect of acidic polysaccharides on the biogeochemistry of iron in the marine environment
    report stated the effect of anthropogenic CO2 emissions on global warming and John Martin s Iron Hypothesis Martin and J H 1990 relating atmospheric dust deposition a major source of iron to the surface ocean to the CO2 concentration in the atmosphere and the last ice age culminating in the well known sentence Give me half a tanker of iron and I rsquo ll give you a new ice age Since then several large scale in situ Fe fertilisation experiments revealed that in large areas of the ocean the so called high nutrient low chlorophyll HNLC areas phytoplankton growth is partly limited by depleted Fe conditions Geider et al 1994 De Baar and Boyed 2000 Boyd et al 2007 The ocean receives Fe from upwelling riverine input melting icebergs atmospheric dust input input from anoxic sediments hydrothermal vents and direct recycling by organisms Tovar Sanchez et al 2007 However in HNLC regions the Fe input to surface waters is very low resulting in Fe limitation of phytoplankton growth Fe is an important nutrient for marine phytoplankton Geider et al 1994 Falkowski et al 1998 Morel and Price 2003 being essential in metabolic reactions like the photosynthetic electron transport and the

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-313C-9 (2016-02-15)
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  • Physical and chemical constraints on core-mantle differentiation in terrestrial planets
    6 0 MB Google View Download Kategorien Erdinneres insgesamt Geophysik Planeteninneres Astronomie Experimentelle Geochemie Zur Langanzeige Zusammenfassung In this study a physical mechanism and geochemical parameters have been examined in high pressure and high temperature experiments in order to place constraints on the conditions and the manner by which core mantle differentiation occurred on Earth and terrestrial planets The wetting characteristics of liquid Fe Si alloys in a matrix of the respective predominating stable silicate mantle mineral forsterite or silicate perovskite at pressures of 2 5 and 25 GPa and temperatures of 1600 2000 ʿC were studied by determining the liquid metal solid silicate contact angles The median angle values from texturally equilibrated samples were found to be independent of pressure temperature silicate mineralogy and the Si content in the metal fraction and range between 130ʿ and 140ʿ which is far above the critical wetting boundary of 60ʿ This shows that within the studied range of conditions dissolved Si does not lower the surface energies between Fe rich liquids and silicate mantle grains As a consequence under reducing conditions the presence of Si in the metal phase of planetary bodies would not have induced or aided percolative flow as the

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-31AD-D (2016-02-15)
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  • Microbial ecology of anaerobic carbon mineralization in Namibian shelf sediments
    an essential component of the Namibia Gas NAMIBGAS project which aims to improve the understanding of the rate and fluxes of hydrogen sulfide and methane to the sediment surface and into the water column on the Namibian shelf which is one of the most productive upwelling systems on Earth Organic matter degradation in the sediment drives hydrogen sulfide production the maintenance of anoxia and methane formation Therefore the primary aims of the thesis are to study carbon transformation processes within the sediment determine the reactivity of organic carbon in the sediment and investigate the control of microbial community structure and activity by the amount and accessibility of carbon sources The emphasis is on linking microbial community structure identity to their function activity to provide new insights into the microbial ecology that controls carbon turnover in these upwelling sediments By studying the stepwise degradation of organic carbon a complete process overview of organic carbon mineralization could be obtained Firstly the diagenetic transformation of dissolved organic carbon DOC in particular dissolved carbohydrates was studied by using both biogeochemical methods and molecular techniques The bulk sediment composition pore water chemistry polysaccharide hydrolysis rates 35S sulfate reduction rates and the abundance of active bacteria

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3142-A (2016-02-15)
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  • Seasonal dynamics and characterization of coccolithophore export production in two major upwelling regions
    Geochemische Kreislaufmodelle Zur Langanzeige Zusammenfassung Coccolithophores a major group of the nanophytoplankton belong to the class Prymnesiophyceae The cells of coccolithophores are typically surrounded by layer s of calcium carbonate plates the coccoliths Certain coccolithophores can be assigned to particular water masses or to photic zone characteristics and therefore single species as well as whole assemblages can be used as oceanographical indicators for the present and the past Due to

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-313A-D (2016-02-15)
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  • 3D-Modellierungen der strukturellen Entwicklung der Vorerzgebirgssenke im Raum der Altbergbaugebiete Zwickau und Lugau, Oelsnitz
    Oelsnitz Steinborn Henry Erstveröffentlichung 2008 Univ Freiberg Sachsen Doktorarbeit Verlagsversion Deutsch Zum Verlinken Bookmarken http hdl handle net 11858 00 1735 0000 0001 313E 5 Dateiname Steinborn2008 pdf PDF 31 9 MB Google View Download Kategorien Hydrogeologie einzelner Regionen Saxothuringikum Geologie Zur Langanzeige Zusammenfassung Die geologische Entwicklung der Vorerzgebirgs Senke war bereits mehrfach Gegenstand geowissenschaftlicher Arbeiten Darauf aufbauend war es möglich unter erstmaliger Verwendung von computergenerierten 3D Modellen die Kenntnisse über die Vorerzgebirgs Senke unter Einbindung neuer Gesichtspunkte zu erweitern Auf der Basis der vom Autor entwickelten geologisch tektonischen 3D Modellen der Steinkohlenreviere von Zwickau einschließlich des Mülsenfeldes sowie Lugau Oelsnitz und unter Berücksichtigung der Ergebnisse neuerer Kartierungen und Untersuchungen in diesen Gebieten werden Vorstellungen zur möglichen geologischen Entwicklung der Vorerzgebirgs Senke dargelegt Dabei wird ein vollständiges Bild der Beckenentwicklung beginnend ab Westfal B C Flöha Becken bis rezent für den Senkungsraum dargestellt Insgesamt flossen in die Auswertung 27 Flözverbreitungskarten M 1 5 000 der ehemaligen Steinkohlenreviere 121 Schachtprofile 139 Bohrungen 100 m und ca 50 geologischtektonische Profilschnitte unterschiedlicher Orientierung ein Weiterhin konnten die Ergebnisse der Revisionskartierungen der Meßtischblätter Zwickau Zwickau Ost Wilkau Haslau und Planitz mit in die Analyse und Modellierung eingebunden werden Share on Das Dokument erscheint in

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-313E-5 (2016-02-15)
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  • Inorganic geochemical redox proxies - indicators for rapid paleoenvironmental changes and related diagenetic processes in recent and ancient marine sediments
    marine sediments März Christian Erstveröffentlichung 2008 Univ Bremen Doktorarbeit Verlagsversion Deutsch Zum Verlinken Bookmarken http hdl handle net 11858 00 1735 0000 0001 3141 C Dateiname Maerz2007 pdf PDF 3 6 MB Google View Download Kategorien Meeresablagerungen Geologie Geochemie der ozeanischen Sedimente Zur Langanzeige Zusammenfassung Deep sea fan early diagenesis susceptibility anaerobic oxidation of methane black shale anoxia oceanic anoxic event trace elements iron phosphorus sediment source redox changes enrichment factors sequential extraction In the context of present day changes of atmo hydro geo and biosphere processes there is growing interest to decipher rapid paleoenvironmental changes in the geological past Marine deposits provide valuable insights into paleoenvironmental conditions that prevailed during their deposition if we know how to read the respective signals in the sedimentary record However caution is demanded as primary signals of past environmental conditions can be altered by postdepositional diagenetic processes In the presented work we will show the potentials but also limitations of inorganic geochemical proxies to record signals of abrupt paleoenvironmental shifts in the terrestrially dominated Late Quaternary deposits of the Zambesi deep sea fan SE African margin and in a fully marine Late Cretaceous black shale succession on Demerara Rise NW South American margin

    Original URL path: http://e-docs.geo-leo.de/handle/11858/00-1735-0000-0001-3141-C (2016-02-15)
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