Global ETD Search

11	Temperature extension of NaCl Pitzer coefficients and ∆RG°(NaCl) Voigt, Wolfgang 20 April 2022 (has links) The general temperature range for THEREDA is currently limited to 0 to about 110°C. For the important electrolyte NaCl there are thermodynamic data available to 200°C and above. To cover this larger temperature range for the Pitzer coefficients, a refit of the temperature functions of Greenberg, J. P. and Møller, N. (Geochim. Cosmochim. Acta 53 (1989) 2503-2518) is presented. A corresponding function for the solubility constant of NaCl is deduced from IUPAC recommended data. The data set for NaCl, thus extended in its range of validity up to 200°C, is implemented in THEREDA. info:eu-repo/classification/ddc/540 ddc:540 Datensammlung Chloride Hydrochemie Meersalz Meerwasser Salz Salzlösung Thermochemie Thermodynamische Eigenschaft Thermodynamisches System
12	Hexary System of Oceanic Salts – Polythermal Pitzer Dataset (numerical supplement) Voigt, Wolfgang 20 April 2022 (has links) For the polythermal Pitzer dataset of the hexary system of oceanic salts (Na+, K+, Mg+2, Ca+2, Cl-, SO4-2 - H2O) including acids and hydroxides the data selection is documented in detail in the report “THEREDA - Thermodynamische Referenzdatenbasis” (Altmaier et al. 2011, https://www.grs.de/de/aktuelles/publikationen/grs-265-thereda-thermodynamische-referenzdatenbasis-abschlussbericht). The present short communication supplements this report by the numerical values of all temperature coefficients. info:eu-repo/classification/ddc/540 ddc:540 Datensammlung Chloride Hydrochemie Meersalz Meerwasser Salz Salzlösung Thermochemie Thermodynamische Eigenschaft Thermodynamisches System
13	Lower Ocean Crust beneath Slow-Spreading Ridges: a Combined Oxygen Isotopic and Elemental in-situ Study on Hole 735B Gabbros / Lower Ocean Crust beneath Slow-Spreading Ridges: a Combined Oxygen Isotopic and Elemental in-situ Study on Hole 735B Gabbros Gao, Yongjun 28 June 2004 (has links) No description available. Mathematics and Computer Science mittelozeanische Rücken untere Kruste Gabbros Meerwasser Sauerstoffisotopen diffusion 550 Geowissenschaften mid ocean ridges lower crust gabbros seawater oxygen isotope diffusion 38.32 VJJ 110: Geochemie der Stabilen Isotopen VJJ 300: Geochemie der Spurenelemente
14	Variable-Density Flow Processes in Porous Media On Small, Medium and Regional Scales Walther, Marc 03 November 2014 (has links) (PDF) Nowadays society strongly depends on its available resources and the long term stability of the surrounding ecosystem. Numerical modelling has become a general standard for evaluating past, current or future system states for a large number of applications supporting decision makers in proper management. In order to ensure the correct representation of the investigated processes and results of a simulation, verification examples (benchmarks), that are based on observation data or analytical solutions, are utilized to evaluate the numerical modelling tool. In many parts of the world, groundwater is an important resource for freshwater. While it is not only limited in quantity, subsurface water bodies are often in danger of contamination from various natural or anthropogenic sources. Especially in arid regions, marine saltwater intrusion poses a major threat to groundwater aquifers which mostly are the exclusive source of freshwater in these dry climates. In contrast to common numerical groundwater modelling, density-driven flow and mass transport have to be considered as vital processes in the system and in scenario simulations for fresh-saltwater interactions. In the beginning of this thesis, the capabilities of the modelling tool OpenGeoSys are verified with selected benchmarks to represent the relevant non-linear process coupling. Afterwards, variable-density application and process studies on different scales are presented. Application studies comprehend regional groundwater modelling of a coastal aquifer system extensively used for agricultural irrigation, as well as hydro-geological model development and parametrization. In two process studies, firstly, a novel method to model gelation of a solute in porous media is developed and verified on small scale laboratory observation data, and secondly, investigations of thermohaline double-diffusive Rayleigh regimes on medium scale are carried out. With the growing world population and, thus, increasing pressure on non-renewable resources, intelligent management strategies intensify demand for potent simulation tools and development of novel methods. In that way, this thesis highlights not only OpenGeoSys’ potential of density-dependent process modelling, but the comprehensive importance of variable-density flow and transport processes connecting, both, avant-garde scientific research, and real-world application challenges. Dichteabhängig Strömung Stofftransport Wärmetransport Grundwasser Numerische Simulation Finite-Elemente-Verfahren FEM OpenGeoSys OGS Open Source Benchmark IWAS Oman Al-Batinah Arid Fallstudie Viskosität Gel Dichte thermohaline Stabilität Variable-Density Density-Driven Density-Dependent Flow Mass Transport Heat Transport Numerical Simulation Finite-Element-Method FEM OpenGeoSys OGS Open Source Benchmark IWAS Oman Al-Batinah Case Study Arid Viscosity Gel Density Thermohaline Stability ddc:550 rvk:AR 22140 rvk:AR 22600 Grundwasser Finite-Elemente-Methode Viskosität Temperatur Transportprozess Simulation Dichte <Physik> Fallstudie Salzwasser-Süßwasser-Grenze Salzwasser Meerwasser Oman Open Source Benchmark Semiarides Gebiet Gel Stabilität
15	Variable-Density Flow Processes in Porous Media On Small, Medium and Regional Scales Walther, Marc 07 May 2014 (has links) Nowadays society strongly depends on its available resources and the long term stability of the surrounding ecosystem. Numerical modelling has become a general standard for evaluating past, current or future system states for a large number of applications supporting decision makers in proper management. In order to ensure the correct representation of the investigated processes and results of a simulation, verification examples (benchmarks), that are based on observation data or analytical solutions, are utilized to evaluate the numerical modelling tool. In many parts of the world, groundwater is an important resource for freshwater. While it is not only limited in quantity, subsurface water bodies are often in danger of contamination from various natural or anthropogenic sources. Especially in arid regions, marine saltwater intrusion poses a major threat to groundwater aquifers which mostly are the exclusive source of freshwater in these dry climates. In contrast to common numerical groundwater modelling, density-driven flow and mass transport have to be considered as vital processes in the system and in scenario simulations for fresh-saltwater interactions. In the beginning of this thesis, the capabilities of the modelling tool OpenGeoSys are verified with selected benchmarks to represent the relevant non-linear process coupling. Afterwards, variable-density application and process studies on different scales are presented. Application studies comprehend regional groundwater modelling of a coastal aquifer system extensively used for agricultural irrigation, as well as hydro-geological model development and parametrization. In two process studies, firstly, a novel method to model gelation of a solute in porous media is developed and verified on small scale laboratory observation data, and secondly, investigations of thermohaline double-diffusive Rayleigh regimes on medium scale are carried out. With the growing world population and, thus, increasing pressure on non-renewable resources, intelligent management strategies intensify demand for potent simulation tools and development of novel methods. In that way, this thesis highlights not only OpenGeoSys’ potential of density-dependent process modelling, but the comprehensive importance of variable-density flow and transport processes connecting, both, avant-garde scientific research, and real-world application challenges.:Abstract Zusammenfassung Nomenclature List of Figures List of Tables I Background and Fundamentals 1 Introduction 1.1 Motivation 1.2 Structure of the Thesis 1.3 Variable-Density Flow in Literature 2 Theory and Methods 2.1 Governing Equations 2.2 Fluid Properties 2.3 Modelling and Visualization Tools 3 Benchmarks 3.1 Steady-state Unconfined Groundwater Table 3.2 Theis Transient Pumping Test 3.3 Transient Saltwater Intrusion 3.4 Development of a Freshwater Lens II Applications 4 Extended Inverse Distance Weighting Interpolation 4.1 Motivation 4.2 Extension of IDW Method 4.3 Artificial Test and Regional Scale Application 4.4 Summary and Conclusions 5 Modelling Transient Saltwater Intrusion 5.1 Background and Motivation 5.2 Methods and Model Setup 5.3 Simulation Results and Discussion 5.4 Summary, Conclusion and Outlook 6 Gelation of a Dense Fluid 6.1 Motivation 6.2 Methods and Model Setup 6.3 Results and Conclusions 7 Delineating Double-Diffusive Rayleigh Regimes 7.1 Background and Motivation 7.2 Methods and Model Setup 7.3 Results 7.4 Conclusions and Outlook III Summary and Conclusions 8 Important Achievements 9 Conclusions and Outlook Bibliography Publications Acknowledgements Appendix info:eu-repo/classification/ddc/550 ddc:550

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