Rock Damage and Fluid Transport, Part I     

Georg Dresen  Ove Stephansson  Arno Zang 《Pure and Applied Geophysics》2006,163(5-6):915-916

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Geothermal investigations in the Bohus granite area in southwestern Sweden     

Ove Landstrm  Sven ke Larson  Gustaf Lind  David Malmqvist 《Tectonophysics》1980,64(1-2)

Heat generation and heat flow were determined for the Bohus granite massif in western Sweden. This is the start of a major program concerning geothermal energy in Sweden. Neutron activation analyses, temperature measurements, thermal conductivity measurements have been carried out. As was expected the result, 76 mW m⁻², shows that even old Precambrian shields locally exhibit much higher values than normal.  相似文献   

The capture of comets by Jupiter     

Ove Havnes 《Astrophysics and Space Science》1969,5(3):272-282

The capture of comets with parabolic orbits by Jupiter is investigated. The influence of the gravitational force of the Sun on the cometary orbit during the passage of Jupiter's sphere of influence is taken into account. A comparison of the present results with previous calculations demonstrate the importance of the solar perturbations.It is also shown that captures of comets with parabolic orbits and repeated close passages to Jupiter cannot explain all of the observed cometary orbits found in the family of Jupiter.  相似文献   

Determining the equivalent permeability tensor for fractured rock masses using a stochastic REV approach: Method and application to the field data from Sellafield,UK   总被引：5，自引：0，他引：5  

Ki-Bok?MinEmail author  Lanru?Jing  Ove?Stephansson 《Hydrogeology Journal》2004,12(5):497-510

A numerical procedure to determine the equivalent permeability tensor of a fractured rock is presented, using a stochastic REV (Representative Elementary Volume) concept that uses multiple realizations of stochastic DFN (Discrete Fracture Network) models. Ten square DFN models are generated using the Monte Carlo simulations of the fracture system based on the data obtained from a site characterization program at Sellafield, Cumbria, UK. Smaller models with varying sizes of from 0.25 m×0.25 m to 10 m×10 m are extracted from the generated DFN models and are used as two-dimensional geometrical models for calculation of equivalent permeability tensor. The DFN models are also rotated in 30º intervals to evaluate the tensor characteristics of calculated directional permeability. Results show that the variance of the calculated permeability values decreases significantly as the side lengths of the DFN models increase, which justifies the existence of a REV. The REV side length found in this analysis is about 5 m and 8 m with 20% and 10% acceptable variations, respectively. The calculated directional permeability values at the REV size have tensor characteristic that is confirmed by a close approximation of an ellipse in a polar plot of the reciprocal of square roots of the directional permeability.

Ki-Bok MinEmail: Phone: +46-8-7907919Fax: +46-8-7906810

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DECOVALEX Project: from 1992 to 2007   总被引：3，自引：0，他引：3  

Chin-Fu Tsang  Ove Stephansson  Lanru Jing  Fritz Kautsky 《Environmental Geology》2009,57(6):1221-1237

The DECOVALEX project is a unique international research collaboration, initiated in 1992, for advancing the understanding and mathematical modelling of coupled thermo-hydro-mechanical (THM) and thermo-hydro-mechanical-chemical (THMC) processes in geological systems—subjects of importance for performance assessment of radioactive waste repositories in geological formations. From 1992 up to 2007, the project has made important progress and played a key role in the development of numerical modelling of coupled processes in fractured rocks and buffer/backfill materials. The project has been conducted by research teams supported by a large number of radioactive-waste-management organizations and regulatory authorities, including those of Canada, China, Finland, France, Japan, Germany, Spain, Sweden, UK, and the USA. Through this project, in-depth knowledge has been gained of coupled THM and THMC processes associated with nuclear waste repositories, as well as numerical simulation models for their quantitative analysis. The knowledge accumulated from this project, in the form of a large number of research reports and international journal and conference papers in the open literature, has been applied effectively in the implementation and review of national radioactive-waste-management programmes in the participating countries. This paper presents an overview of the project.  相似文献   

On the SAR derived alert in the detection of oil spills according to the analysis of the EGEMP     

Guido Ferraro  Björn Baschek  Ove Njoten  Michele Vespe 《Marine pollution bulletin》2010,60(1):91-102

Satellite services that deliver information about possible oil spills at sea currently use different labels of “confidence” to describe the detections based on radar image processing. A common approach is to use a classification differentiating between low, medium and high levels of confidence. There is an ongoing discussion on the suitability of the existing classification systems of possible oil spills detected by radar satellite images with regard to the relevant significance and correspondence to user requirements. This paper contains a basic analysis of user requirements, current technical possibilities of satellite services as well as proposals for a redesign of the classification system as an evolution towards a more structured alert system. This research work offers a first review of implemented methodologies for the categorisation of detected oil spills, together with the proposal of explorative ideas evaluated by the European Group of Experts on satellite Monitoring of sea-based oil Pollution (EGEMP).  相似文献   

ISRM Suggested Method for the Determination of Mode II Fracture Toughness     

Tobias Backers  Ove Stephansson 《Rock Mechanics and Rock Engineering》2012,45(6):1011-1022

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World Stress Map Database as a Resource for Rock Mechanics and Rock Engineering     

Arno Zang  Ove Stephansson  Oliver Heidbach  Silke Janouschkowetz 《Geotechnical and Geological Engineering》2012,30(3):625-646

Knowledge of the in situ stress state is of key importance for rock engineering. We inform the reader about the World Stress Map (WSM) database and its application to rock mechanics and rock engineering purpose, and in particular the orientation of maximum horizontal stress. We discuss the WSM and the quality ranking system of stress orientation data. We show one example of discrete-measured and computed-smoothed stress orientations from central and northern Europe with respect to relative plate velocity trajectories. We give first insights into ongoing development of a second, more Quantitative World Stress Map database which compiles globally rock-type specific stress magnitudes versus depth. We discuss the vertical stress component, and the lateral stress coefficient versus depth for different rock types. We display stress magnitudes in 2D and 3D stress space, and investigate stress ratios in relation to depth, lithology and tectonic faulting regime.  相似文献   

The dynamism of clustering: Interweaving material and discursive processes     

Arnt Fløysand  Stig-Erik Jakobsen  Ove Bjarnar 《Geoforum》2012,43(5):948-958

The aim of this paper is to contribute to an understanding of clusters, including both the material and discursive dynamism of cluster construction, and shed light on how clusters—once established—affect the actors, institutions and processes that constitute them. It does this by viewing clusters as an actant, i.e. something that acts or to which activity is granted by others. The empirical analysis examines two clusters in the public cluster programme Norwegian Centre of Expertise (NCE): the Møre maritime cluster and the Hordaland subsea cluster. It focuses on the type of development paths they are following and how the material and discursive processes are interweaved in these paths. The clusters are related to the concept of cluster construction, which is triggered by ideas, representations, policy and industry practice. The Møre maritime cluster is characterized by bottom-up clustering processes and illustrates how the material practices of firms can trigger clustering processes such as the establishment of a cluster and the identification of a prototype of best cluster practice. On the other hand, the Hordaland subsea cluster expresses a top-down process and how the ideal world of academics and policy-making can encourage processes of clustering among co-located firms. Based on these observations of material and discursive interweaved clustering processes and how they affect both those who are practicing and those who are promoting them, we find it reasonable to argue for a stronger awareness of such feedback loops in cluster studies.  相似文献   

Accumulation in Svalbard glaciers deduced from ice cores with nuclear tests and Chernobyl reference layers   总被引：1，自引：0，他引：1  

Jean Francis Pinglot  Michel Pourchet  Bernard Lefauconnier  Jon Ove Hagen  Elisabeth Isaksson  Rein Vaikmäe  Kokichi Kamiyama 《Polar research》1999,18(2):315-321

Mean net annual balance and the related spatio-temporal variations have been determined on the basis of well-dated artificial layers in shallow ice cores (Chernobyl, 1986, and atmospheric thermonuclear tests, mainly in 1961-62 in Novaya Zemlya). Seventy ice cores from 13 Svalbard glaciers have been analysed. On each glacier, in its accumulation area and at the highest elevation, one ice core was recovered down to about 40 m and sampled for radioactivity measurements to determine the 1986 and 1962-63 layer (1954 was the initial date of the nuclear tests). For each glacier, at least five complementary ice cores from the accumulation area were analysed to determine the Chernobyl reference layer. Six ice cores exhibit both the Chernobyl and nuclear tests layers and are of special interest in this study.
This work provides new data on the deposition rates of natural and artificial radioisotopes. Using ice cores samples from the Arctic glaciers, even with superimposed ice accumulation, it is possible to distinguish between the Chernobyl and the nuclear tests fallouts. This work also shows that the mean annual net balance did not significantly change for at least five ice core locations in the Svalbard glaciers for the two periods extending from 1963 to 1986 to the recent date of drilling.  相似文献