53 research outputs found
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
Funktionelle hochverzweigte Polyester mit Anwendungen in Blends, Beschichtungen und in dünnen Filmen
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
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