Geothermal Potential of the Brenner Base Tunnel—Initial Evaluations

Increasing demands on mobility and transport, but limited space above ground, lead to new traffic routes being built, even more underground in the form of tunnels. In addition to improving the traffic situation, tunnels offer the possibility of contributing to climate-friendly heating by indirectly serving as geothermal power plants. In this study, the geothermal potential of the future longest railway tunnel in the world, the Brenner Base Tunnel, was evaluated. At the Brenner Base Tunnel, warm water naturally flows from the apex of the tunnel towards the city of Innsbruck, Austria. In order to estimate its geothermal potential, hydrological data of discharge rates and temperatures were investigated and analyzed. The investigations indicated the highest geothermal potential in the summertime, while the lowest occurs during winter. It could be shown that these variations were a result of cooling during discharge through areas of low overburden (mid mountain range), where the tunnel atmosphere is increasingly influenced by the air temperatures outside the tunnel. Nevertheless, the calculations showed that there will be a usable potential after completion of the tunnel

Extensional crustal-scale shear zones in the Western Cyclades (Kea, Greece)

Intense seismicity and intensely developed active and ancient fault systems are common to the Aegean Region. Extending/ thinning crust involves a complex interplay of (1) Gulf of Corinth riftexpansion, (2) west- and south-ward retreat of the Hellenic Trench, (3) westward impingement of the Anatolian Platen, and/or (4) propagation of the Anatolian Fault system into the Aegean. New geological/structural investigations on Kea (also known as Tzia), in the Western Cyclades reveal a low angle crustal-scale, detachment-type ductile shear zone probably formed during Miocene extension and thinning of the continental crust...conferenc

Kinematics and deformation structures in a crustal-scale shear zone on Kea (W. Cyclades, Greece)

It is generally agreed upon that the exhumation of metamorphic rocks in the Aegean is caused by post orogenic extension in the late Oligocene to early Miocene. This extension is in principle largely accommodated by low-angle crustal detachment faulting possibly resulting in the formation of metamorphic core complexes (MCC). Here, we present data from recent structural investigations on the island of Kea in the W. Cyclades, Greece. Our work focussed in the north of the island. Of the ca. 270m total structural thickness that was mapped, the entire section of rocks are highly strained. Exhumation during progressive deformation is recorded by the transition from ductile to brittle/ductile to brittle conditions. The regional characteristics and types of deformation structures vary depending on the protolith and the intensity of strain...conferenc

Late stage evolution of the Serifos Metamorphic Core Complex (Cyclades, Greece)

The island of Serifos is located in the Western Cyclades within the Attic- Cycladic metamorphic belt. It represents the westward continuation of an arcuate belt of Metamorphic Core Complexes with intrusions of late syn-post tectonic intrusions younging from East (e.g. Naxos main activity ca. 12Ma) to West (e.g. Serifos with 9–8Ma). In scientific discussions the dominance of probably continuous extension since ca. 30Ma (e.g. Jolivet & Faccenna, 2000) and the presence of Metamorphic Core Complexes (Lister et al. 1984) is accepted. The speculated roll-back of the subducting plate possibly started due to the slowing down of absolute plate convergence rate between Africa and Eurasia. This model is attractive, because it would also explain the shift from a compressional Andean-type regime to an extensional Mariana-type regime (Jolivet & Faccenna 2000). Contrary to the kinematic directions reported from the Central and Eastern Cyclades, the movement of the hanging wall of the Serifos Metamorphic Core Complex is south directed. The island’s main part is occupied by an undeformed granodiorite. Early granitic intrusions intruded into low-grade M2-crystalline rocks that have been overprinted to as high as amphibolite facies conditions due to contact metamorphism. Parts of these rocks (gneisses and amphibolites) as well as the early intrusions are deformed to mylonites (Grasemann et al. 2004).conferenc

Numerical simulations of the Warm-Hot Intergalactic Medium

In this paper we review the current predictions of numerical simulations for the origin and observability of the warm hot intergalactic medium (WHIM), the diffuse gas that contains up to 50 per cent of the baryons at z~0. During structure formation, gravitational accretion shocks emerging from collapsing regions gradually heat the intergalactic medium (IGM) to temperatures in the range T~10^5-10^7 K. The WHIM is predicted to radiate most of its energy in the ultraviolet (UV) and X-ray bands and to contribute a significant fraction of the soft X-ray background emission. While O VI and C IV absorption systems arising in the cooler fraction of the WHIM with T~10^5-10^5.5 K are seen in FUSE and HST observations, models agree that current X-ray telescopes such as Chandra and XMM-Newton do not have enough sensitivity to detect the hotter WHIM. However, future missions such as Constellation-X and XEUS might be able to detect both emission lines and absorption systems from highly ionised atoms such as O VII, O VIII and Fe XVII.Comment: 18 pages, 5 figures, accepted for publication in Space Science Reviews, special issue "Clusters of galaxies: beyond the thermal view", Editor J.S. Kaastra, Chapter 14; work done by an international team at the International Space Science Institute (ISSI), Bern, organised by J.S. Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke

Thermal conduction in cosmological SPH simulations

Thermal conduction in the intracluster medium has been proposed as a possible heating mechanism for offsetting central cooling losses in rich clusters of galaxies. In this study, we introduce a new formalism to model conduction in a diffuse ionised plasma using smoothed particle hydrodynamics (SPH), and we implement it in the parallel TreePM/SPH-code GADGET-2. We consider only isotropic conduction and assume that magnetic suppression can be described in terms of an effective conductivity, taken as a fixed fraction of the temperature-dependent Spitzer rate. We also account for saturation effects in low-density gas. Our formulation manifestly conserves thermal energy even for individual and adaptive timesteps, and is stable in the presence of small-scale temperature noise. This allows us to evolve the thermal diffusion equation with an explicit time integration scheme along with the ordinary hydrodynamics. We use a series of simple test problems to demonstrate the robustness and accuracy of our method. We then apply our code to spherically symmetric realizations of clusters, constructed under the assumptions of hydrostatic equilibrium and a local balance between conduction and radiative cooling. While we confirm that conduction can efficiently suppress cooling flows for an extended period of time in these isolated systems, we do not find a similarly strong effect in a first set of clusters formed in self-consistent cosmological simulations. However, their temperature profiles are significantly altered by conduction, as is the X-ray luminosity.Comment: 14 pages, 7 figures, accepted by MNRAS, high resolution version available at http://www.mpa-garching.mpg.de/~jubelgas/conduction.pdf. Fixed typos in eq. 20,22,2

Instandsetzung und bauliche Sanierung von Eisenbahntunnel am Beispiel des Arlbergbahntunnels

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in engl. SpracheBei der Thematik der Tunnelsanierung handelt es sich um eine sehr aktuelle und praxisbezogene Fragestellung, was u.a. daran zu erkennen ist, dass der Umfang an Tunnelsanierungen in den letzten Jahren stetig ansteigt. Alleine in Österreich sind in den nächsten zehn bis fünfzehn Jahren insgesamt ca. 90 Tunnelbauwerke von einem umfangreicheren Sanierungs- oder Erneuerungsbedarf betroffen. Die Ursachen hierfür sind vielfältig. Zum einen sind es der alterungsbedingte Zustand der gemauerten Gewölbe, der einen gefahrlosen Betrieb der Tunnelanlage nicht mehr ermöglicht sowie ein unzureichendes, nach neuen Normen und Richtlinien nicht mehr zulässiges Lichtraumprofil. Auch aus Gründen des Brandschutzes und anderen sicherheitstechnischen Fragestellungen werden in Zukunft noch zahlreiche Tunnel an die aktuellen Sicherheitsbestimmungen adaptiert werden müssen. Die rechtlichen Vorschriften und technischen Rahmenbedingungen, welche bei der Sanierung von Tunnelanlagen eingehalten werden müssen, sind dabei sehr komplex. Neben gesetzlichen Vorgaben von zentralen Stellen, wie z.B. der Europäischen Union, existieren eine Reihe nationaler Vorschriften und Regelungen. Auch die Baumaßnahmen und angewendeten Bauverfahren selbst sind einem ständigen Wandel unterworfen und werden laufend an den neuesten Stand der Technik angepasst. In der vorliegenden Diplomarbeit werden deshalb Ursachen, die eine Tunnelsanierung erforderlich machen sowie Maßnahmen und Bauverfahren zur Tunnelsanierung im Detail erörtert und anhand von verschiedenen Beispielen aus der Praxis ausgeführt. Weiters werden die derzeit gültigen Richtlinien und Vorschriften sowie der aktuelle Stand der Sicherheits- und Brandschutzmaßnahmen besprochen und auf die Notwendigkeit detaillierter Vorerkundungsmaßnahmen hingewiesen. Auch die Versinterungsproblematik, welche in der Tunnelentwässerung oft zu Bauschäden und schlussendlich zur Notwendigkeit der Durchführung von Sanierungsmaßnahmen führt, wird im Zuge dieser Diplomarbeit eingegangen. Die angeführten Themengebiete werden zunächst allgemein und anschließend am aktuellen Fallbeispiel des Arlberg-Eisenbahntunnels behandelt.Tunnel refurbishment of railway tunnels using the example of the Arlberg rail tunnel Currently, tunnel refurbishment measures concern a large number of tunnel buildings. In Austria alone, there are 90 Tunnels that need to be modernized or rehabilitated extensively over the next ten to fifteen years due to different reasons. Besides the fact that the age-related condition of the brick-built arches and vaults is inadequate and a safe operation cannot be ensured any longer, the minimum clearance outline doesn't meet the requirements of the newest standards and guidelines. Also for fire protection reasons and other technical safety problems, numerous tunnel buildings require rehabilitation of their physical fabric and safety equipment in the near future. Legal standards and technical framework conditions concerning the refurbishment of a tunnel are very complex. Besides legal regulations from a central unit, like the European Union, there are a number of relevant national safety standards. Also the building measures and construction methods are continuously developing and are constantly upgraded to the latest technological standards. This thesis deals with the reasons that make tunnel renovation work necessary and describes the building measures and construction methods for tunnel refurbishment in general terms and using specific examples from practice. Furthermore, the currently valid guidelines and appropriate safety and fire protection measures are outlined. Moreover, the necessity of detailed preliminary reconnaissance measures are indicated. The subject matter sintering and clogging of the drainage system is also discussed in the course of this work. The mentioned topics are described in general terms at first and by using the current example of the Arlberg railway tunnel.8

High-Durability Concrete Using Eco-Friendly Slag-Pozzolanic Cements and Recycled Aggregate

Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon dioxide (CO2) into the atmosphere, and the exploitation of aggregate for concrete results in a reduction in natural resources. This contrasts with infrastructure development, surging urbanization, and the demand for construction materials with increasing requirements in terms of durability and strength. A possible answer to this is eco-efficient, high-performance concrete. This article illustrates basic material investigations to both, using eco-friendly cement and recycled aggregate from tunneling to produce structural concrete and inner shell concrete, showing high impermeability and durability. By replacing energy- and CO2-intensive cement types by slag-pozzolanic cement (CEM V) and using recycled aggregate, a significant contribution to environmental sustainability can be provided while still meeting the material requirements to achieve a service lifetime for the tunnel structure of up to 200 years. Results of this research show that alternative cements (CEM V), as well as processed tunnel spoil, indicate good applicability in terms of their properties. Despite the substitution of conventional clinker and conventional aggregate, the concrete shows good workability and promising durability in conjunction with adequate concrete strengths