26,211 research outputs found
International Year of the Planet Earth (IYPE) und unsere FH-DGG-Tagung in Göttingen, Mai 2008
No full textA review on challenges in the assessment of geomechanical rock performance for deep geothermal reservoir development
No full textControls on runoff generation along a steep climatic gradient in the Eastern Mediterranean
No full textAbstractStudy regionLower Jordan River.Study focusThe main aim of this study was to identify differences in catchment runoff reactions across a variety of scales and a strong climatic gradient and to correlate them to physical catchment properties. For this purpose we observed rainfall and runoff responses on a hillslope (1000m2) and in several nested catchments (3.2–129km2) over a period of five years. Catchment characteristics and surface cover types were derived from high-resolution aerial images. To gain process understanding a single high magnitude event was analysed in detail using information from soil moisture plots.New hydrological insights for the regionOur results show that runoff in the semi-arid headwater area is strongly related to long lasting rainfall events of high amounts and is predominantly generated by saturation excess overland flow (SOF). Observations from the arid runoff plot indicated a strongly contrasting behaviour with dominating Hortonian overland flow (HOF). At catchment scale we found an accentuated runoff response when we compared arid with semi-arid conditions, which can be attributed to different geological substrate, more abundant rock surfaces, shallower soil and sparser vegetation cover. Identified strong correlations between event rainfall and runoff volumes may provide promising options for the assessment and management of surface runoff as a water resource
Studying the Flow Dynamics of a Karst Aquifer System with an Equivalent Porous Medium Model
No full textThe modeling of groundwater flow in karst aquifers is a challenge due to the extreme heterogeneity of its hydraulic parameters and the duality in their discharge behavior, that is, rapid response of highly conductive karst conduits and delayed drainage of the low-permeability fractured matrix after recharge events. There are a number of different modeling approaches for the simulation of the karst groundwater dynamics, applicable to different aquifer as well as modeling problem types, ranging from continuum models to double continuum models to discrete and hybrid models. This study presents the application of an equivalent porous model approach (EPM, single continuum model) to construct a steady-state numerical flow model for an important karst aquifer, that is, the Western Mountain Aquifer Basin (WMAB), shared by Israel and the West-Bank, using MODFLOW2000. The WMAB was used as a catchment since it is a well-constrained catchment with well-defined recharge and discharge components and therefore allows a control on the modeling approach, a very rare opportunity for karst aquifer modeling. The model demonstrates the applicability of equivalent porous medium models for the simulation of karst systems, despite their large contrast in hydraulic conductivities. As long as the simulated saturated volume is large enough to average out the local influence of karst conduits and as long as transport velocities are not an issue, EPM models excellently simulate the observed head distribution. The model serves as a starting basis that will be used as a reference for developing a long-term dynamic model for the WMAB, starting from the pre-development period (i.e., 1940s) up to date
The SALAM Initiative: Strategies for Solving the Water Deficit Problem in the Middle East
No full textIm Rahmen der "Forschung für Nachhaltigkeit" (FONA) werden in den Jahren 2020 bis 2025 vom Bundesministerium für Bildung und Forschung (BMBF) 4 Mrd. Euro an Fördermitteln bereitgestellt, um die Umsetzung der Nachhaltigkeitsziele voranzutreiben. Die Verminderung von Wasserkrisen auf globaler Ebene ist dabei ein Themenschwerpunkt der neuen FONA-Strategie, wobei dem Nahen Osten, bedingt durch den extremen Wasserstress der Region, eine besondere Bedeutung beigemessen wird
The SALAM Initiative: Strategies for Solving the Water Deficit Problem in the Middle East
No full textIm Rahmen der "Forschung für Nachhaltigkeit" (FONA) werden in den Jahren 2020 bis 2025 vom Bundesministerium für Bildung und Forschung (BMBF) 4 Mrd. Euro an Fördermitteln bereitgestellt, um die Umsetzung der Nachhaltigkeitsziele voranzutreiben. Die Verminderung von Wasserkrisen auf globaler Ebene ist dabei ein Themenschwerpunkt der neuen FONA-Strategie, wobei dem Nahen Osten, bedingt durch den extremen Wasserstress der Region, eine besondere Bedeutung beigemessen wird
Tracer design for tracking thermal fronts in geothermal reservoirs
No full textThis paper describes the first steps in the design of new custom-made tracers for the investigation of thermal characteristics in deep geothermal reservoirs. Based on ester hydrolysis, the influences of different substituents on the reaction kinetics are studied in detail using the analog phenol acetates under the influence of varying pH and temperatures. Furthermore, a 2-ethylbutyl-2-naphthol-6-sulfonic ester is tested in laboratory experiments for its applicability as a practical thermo-sensitive tracer, considering also the influences of brine and rock matrix. The reaction is shown to be strongly thermo-sensitive while the reaction kinetics can be varied by two orders of magnitude by altering the sterical hindrance groups. These changes in the reaction kinetics are found to be predictable by using the results of this work. It has been found that the half-life can be decreased by the factor of three, if the reacting group is sterically hindered from one side and by the factor of ten, if the reacting group is hindered from both sides. Also mesomeric and inductive effects of substituents on the aromatic ring have significant effects on reaction rates. The pH-dependency on the reaction speed could be quantified and it is shown that the reaction complete alkaline catalyzed. Therefore, this reaction fulfills the many considerations of a tracer-test, such as varying absolute temperature, test durations, and temperature gradients. (C) 2012 Elsevier Ltd. All rights reserved
A career retrospective of Eddie Sauter, jazz’s overlooked composer and innovator
No full textWith a career that spanned nearly four decades during the height of jazz’s popularity, Eddie Sauter contributed arrangements and compositions to some of the most significant jazz groups in the music’s history. Through his unique style, his constant desire to expand upon his compositional prowess through studies with various classical composers, and his general willingness to experiment with unusual melodic and harmonic gestures, Sauter produced music vastly different from that of most of his contemporaries. It is for this reason that the pensive composer was deemed “twenty years ahead of his time” by several critics of the day. As the chief architect for much of Red Norvo’s songbook in the 1930s, dozens of arrangements and compositions for Benny Goodman in the early 1940s, creative originals for Ray McKinley in the late 1940s, a unique repertoire with co- conspirator Bill Finegan in their jointly led “expanded” big band of the 1950s, and a handful of gems for Stan Getz with orchestral accompaniment in the 1960s, “prolific” barely begins to describe the output of Eddie Sauter. This thesis examines the life of the obscure yet influential composer/arranger Eddie Sauter from his curious beginning in 1914 as the adopted son of a German florist in Nyack, NY, through his forty year career spent among some of jazz’s most important individuals, until his untimely death at the age of 66 in 1981.M.A.Includes bibliographical referencesIncludes vitaby Alex Chilowic
Permeability evolution of Bentheim Sandstone at simulated georeservoir conditions
No full textAbstract Bentheim Sandstone is considered a suitable conventional georeservoir rock even at great depth because of its mineral composition, homogeneity, micro- and macrostructure, and is also used as a reference material in rock deformation tests. However, a full characterization of the permeability at representative depths has never been performed. Here we report new experimental data where the permeability of Bentheim Sandstone is measured both with a simultaneous variation and with a sequential variation of three different variables to simulate georeservoir conditions. The results indicate a decrease in permeability with simulated increasing depth until 2–3 km, followed by a partial permeability recovery until 4–5 km depth. During the exhumation path, initially, permeability is unaffected, but at shallow depths, a sharp increase in permeability is observed, likely due to microcracking. These variations are a consequence of a complex interaction between stress, pore pressure and temperature, highlighting the importance of experiments considering all three variables when studying the evolution of permeability at depth. These results will aid with the accurate estimation of permeability at different georeservoir conditions
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