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- Alfsen, K. H., et al.
(författare)
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Electric field and plasma observations near the magnetopause and bow shock during a rapid compression.
- 1984
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Ingår i: Achievements of the International Magnetospheric Study (IMS). ; , s. 99-104
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Tidskriftsartikel (refereegranskat)abstract
- A fast compressional motion of the magnetopause resulting from the interaction of an interplanetary shock and the Earth's magnetosphere is discussed. The ISEE-1 and 2 satellites were in the frontside magnetosphere before the shock. A magnetosonic wave front, the magnetopause, and the bow shock passed them in a very short time. By a combination of electric and magnetic field data it is possible to determine the magnetosonic and the magnetopause velocity. -from STAR, 23(14), 1985
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6. |
- Lindqvist, Per-Arne, et al.
(författare)
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Behaviour of the crushed zone in rock indentation
- 1983
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Ingår i: Rock Mechanics and Rock Engineering. - 0723-2632 .- 1434-453X. ; 16:3, s. 199-207
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Tidskriftsartikel (refereegranskat)abstract
- Micro hardness tests of compressed crushed rock indicate that the plastic behavior of powder of ductile rocks, in this case a marble, resembles that of intact rock, irrespective of the deformation history of the crushed material. The inelastic deformation of such rocks under a bit can then be treated by plasticity theory. The deformation properties of crushed material of granite and sandstone are of a brittle nature.
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7. |
- Lindqvist, Per-Arne
(författare)
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Energy consumption in disc cutting of hard rock
- 1982
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Ingår i: Tunnelling '82. - London : The Institution of Mining and Metallurgy. - 090048862X ; , s. 189-196
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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8. |
- Lindqvist, Per-Arne, et al.
(författare)
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Indentation fracture development in rock continuously observed with scanning electron microscope
- 1984
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Ingår i: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. - : Elsevier BV. - 0148-9062 .- 1879-2073. ; 21:4, s. 165-182
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Tidskriftsartikel (refereegranskat)abstract
- Indentation tests observed in a scanning electron microscope (SEM) using a sharp and a truncated wedge in three different rocks are reported. By indenting at the edge of one surface and scanning the neighboring surface perpendicular to the direction of loading, it was possible to study the continuous development of cracks throughout the tests. Cracks initiated mainly at the edge and corners of wedges but initiation in the interior of the rock was also observed. Crack initiation and crack paths observed in all rocks are in good agreement with assumed theoretical elastic stress fields, although the nature of the fractures is greatly influenced by different material properties such as grain size, cleavage planes and grain bonding. Recorded force-displacement curves allowed distinction between different fracture processes.
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10. |
- Lindqvist, Per-Arne, 1954-
(författare)
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POTENTIAL OF ISEE IN DIFFERENT PLASMA ENVIRONMENTS.
- 1983
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Ingår i: European Space Agency, (Special Publication) ESA SP. ; , s. 25-33
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Konferensbidrag (refereegranskat)abstract
- The quasistatic electric field experiment on the ISEE-1 satellite uses spherical double probes to measure the electric field. The potential of each probe relative to the plasma potential can be controlled with a bias current, which compensates for the loss of photoelectrons from the probe. Thus, keeping a probe at plasma potential, the satellite potential is measured with reference to the probe. The dependence of the satellite potential on the ambient plasma electron flux is discussed. It is shown theoretically and found experimentally that the satellite potential is proportional to log(n//eT//e** one-half ). Examples are given of how the satellite potential varies in different regions of space penetrated by ISEE.
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