The Experts below are selected from a list of 72429 Experts worldwide ranked by ideXlab platform
P. Lundgren - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Deformation of Etna volcano observed by satellite radar interferometry
IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174), 1998Co-Authors: E. Sansosti, R. Lanari, P. LundgrenAbstract:The authors use radar interferometry of Mt. Etna volcano, Sicily, Italy, to reveal a sequence of Deformation characterized by deflation during the end of the 1993 eruption, inflation from 1993-1995 with an increase in the inflation rate immediately before its resumed eruptive activity in late 1995. This was followed by very low Deformation levels during the following year. They model the Deformation as a point source and find a systematic change in its depth from 9 km during deflation to around 13 km during the subsequent inflation, suggesting a model in which deflation at shallower levels is followed by inflation at greater depth as the volcano system recharges from below before its next eruption. This study demonstrates that radar interferometry provides an important contribution towards understanding the Dynamic Deformation of volcanoes. By revealing large scale changes in their pre-eruption Deformation rates, radar interferometry could play an important role in volcano eruption monitoring.
-
Dynamic Deformation of Etna volcano observed by satellite radar interferometry
IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174), 1998Co-Authors: E. Sansosti, R. Lanari, P. LundgrenAbstract:The authors use radar interferometry of Mt. Etna volcano, Sicily, Italy, to reveal a sequence of Deformation characterized by deflation during the end of the 1993 eruption, inflation from 1993-1995 with an increase in the inflation rate immediately before its resumed eruptive activity in late 1995. This was followed by very low Deformation levels during the following year. They model the Deformation as a point source and find a systematic change in its depth from 9 km during deflation to around 13 km during the subsequent inflation, suggesting a model in which deflation at shallower levels is followed by inflation at greater depth as the volcano system recharges from below before its next eruption. This study demonstrates that radar interferometry provides an important contribution towards understanding the Dynamic Deformation of volcanoes. By revealing large scale changes in their pre-eruption Deformation rates, radar interferometry could play an important role in volcano eruption monitoring.
M T Perezprado - One of the best experts on this subject based on the ideXlab platform.
-
twinning and grain subdivision during Dynamic Deformation of a mg az31 sheet alloy at room temperature
Acta Materialia, 2011Co-Authors: N V Dudamell, I Ulacia, F Galvez, Jan Bohlen, Dietmar Letzig, I Hurtado, M T PerezpradoAbstract:Abstract The microstructural evolution of an AZ31 rolled sheet during Dynamic Deformation at strain rates of ∼103 s−1 has been investigated by electron backscatter diffraction, X-ray and neutron diffraction. The influence of orientation on the predominant Deformation mechanisms and on the recovery processes taking place during Deformation has been systematically examined. The results have been compared with those corresponding to the same alloy tested quasi-statically under equivalent conditions. It has been found that strain rate enhances the activation of { 1 0 1 ¯ 2 } extension twinning dramatically, while contraction and secondary twinning are not significantly influenced. The polarity of { 1 0 1 ¯ 2 } extension twinning is even reversed in some grains under selected testing conditions. Significant grain subdivision by the formation of geometrically necessary boundaries (GNBs) takes place during both quasi-static and Dynamic Deformation of this AZ31 alloy. It is remarkable that GNBs of high misorientations form even at the highest strain rates. The phenomenon of recovery has been found to be orientation dependent.
William F. Teskey - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Deformation monitoring of tall structure using gps technology
Journal of Surveying Engineering-asce, 1995Co-Authors: J W Lovse, William F. Teskey, Gerard Lachapelle, M E CannonAbstract:Dynamic Deformation monitoring of structures such as long bridges, towers, and tall buildings, for the purpose of determining structural vibrations, is now possible using global-positioning-system (GPS) technology. Current non–GPS techniques for measuring structural vibrations (these include vibration measurement with accelerometers, vibration measurement with a laser interferometer, and vibration measurement with an electronic distance measurement instrument) are first briefly outlined, with advantages and disadvantages noted. The specific application, measurement of structural vibrations in the Calgary Tower, Calgary, Alberta, Canada, using GPS receivers in differential mode, is then described. The results show that the Calgary Tower, under wind loading, vibrates with a frequency of about 0.3 Hz in both north-south and east-west directions. The 0.3 Hz vibration frequency measured on the Calgary Tower is within the range of 0.1 Hz to 10Hz expected for structures of this type. When the capability of GPS to monitor structural vibrations is verified by further tests, it could be adopted as a standard technique.
-
Three-dimensional Dynamic Deformation monitoring using a laser-scanning system
Videometrics III, 1994Co-Authors: Nedal N. Al-hanbali, William F. TeskeyAbstract:Non-contact Dynamic Deformation monitoring (e.g. with a laser scanning system) is very useful in monitoring changes in alignment and changes in size and shape of coupled operating machines. If relative movements between coupled operating machines are large, excessive wear in the machines or unplanned shutdowns due to machinery failure will occur. The purpose of non-contact Dynamic Deformation monitoring is to identify the causes of large movements and point to remedial action that can be taken to prevent them. The laser scanning system is a laser-based 3D vision system. The system-technique is based on an auto- synchronized triangulation scanning scheme. The system provides accurate, fast, and reliable 3D measurements and can measure objects between 0.5 m to 100 m with a field of view of 40 degree(s) X 50 degree(s). The system is flexible in terms of providing control over the scanned area and depth. The system also provides the user with the intensity image in addition to the depth coded image. This paper reports on the preliminary testing of this system to monitor surface movements and target (point) movements. The monitoring resolution achieved for an operating motorized alignment test rig in the lab was 1 mm for surface movements and 0.50 m for target movements. Raw data manipulation, local calibration, and the method of relating measurements to control points will be discussed. Possibilities for improving the resolution and recommendations for future development will also be presented.
-
Three-dimensional Dynamic Deformation monitoring using a laser-scanning system
Videometrics III, 1994Co-Authors: Nedal N. Al-hanbali, William F. TeskeyAbstract:Non-contact Dynamic Deformation monitoring (e.g. with a laser scanning system) is very useful in monitoring changes in alignment and changes in size and shape of coupled operating machines. If relative movements between coupled operating machines are large, excessive wear in the machines or unplanned shutdowns due to machinery failure will occur. The purpose of non-contact Dynamic Deformation monitoring is to identify the causes of large movements and point to remedial action that can be taken to prevent them. The laser scanning system is a laser-based 3D vision system. The system-technique is based on an auto- synchronized triangulation scanning scheme. The system provides accurate, fast, and reliable 3D measurements and can measure objects between 0.5 m to 100 m with a field of view of 40 degree(s) X 50 degree(s). The system is flexible in terms of providing control over the scanned area and depth. The system also provides the user with the intensity image in addition to the depth coded image. This paper reports on the preliminary testing of this system to monitor surface movements and target (point) movements. The monitoring resolution achieved for an operating motorized alignment test rig in the lab was 1 mm for surface movements and 0.50 m for target movements. Raw data manipulation, local calibration, and the method of relating measurements to control points will be discussed. Possibilities for improving the resolution and recommendations for future development will also be presented.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
E. Sansosti - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Deformation of Etna volcano observed by satellite radar interferometry
IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174), 1998Co-Authors: E. Sansosti, R. Lanari, P. LundgrenAbstract:The authors use radar interferometry of Mt. Etna volcano, Sicily, Italy, to reveal a sequence of Deformation characterized by deflation during the end of the 1993 eruption, inflation from 1993-1995 with an increase in the inflation rate immediately before its resumed eruptive activity in late 1995. This was followed by very low Deformation levels during the following year. They model the Deformation as a point source and find a systematic change in its depth from 9 km during deflation to around 13 km during the subsequent inflation, suggesting a model in which deflation at shallower levels is followed by inflation at greater depth as the volcano system recharges from below before its next eruption. This study demonstrates that radar interferometry provides an important contribution towards understanding the Dynamic Deformation of volcanoes. By revealing large scale changes in their pre-eruption Deformation rates, radar interferometry could play an important role in volcano eruption monitoring.
-
Dynamic Deformation of Etna volcano observed by satellite radar interferometry
IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174), 1998Co-Authors: E. Sansosti, R. Lanari, P. LundgrenAbstract:The authors use radar interferometry of Mt. Etna volcano, Sicily, Italy, to reveal a sequence of Deformation characterized by deflation during the end of the 1993 eruption, inflation from 1993-1995 with an increase in the inflation rate immediately before its resumed eruptive activity in late 1995. This was followed by very low Deformation levels during the following year. They model the Deformation as a point source and find a systematic change in its depth from 9 km during deflation to around 13 km during the subsequent inflation, suggesting a model in which deflation at shallower levels is followed by inflation at greater depth as the volcano system recharges from below before its next eruption. This study demonstrates that radar interferometry provides an important contribution towards understanding the Dynamic Deformation of volcanoes. By revealing large scale changes in their pre-eruption Deformation rates, radar interferometry could play an important role in volcano eruption monitoring.
N V Dudamell - One of the best experts on this subject based on the ideXlab platform.
-
twinning and grain subdivision during Dynamic Deformation of a mg az31 sheet alloy at room temperature
Acta Materialia, 2011Co-Authors: N V Dudamell, I Ulacia, F Galvez, Jan Bohlen, Dietmar Letzig, I Hurtado, M T PerezpradoAbstract:Abstract The microstructural evolution of an AZ31 rolled sheet during Dynamic Deformation at strain rates of ∼103 s−1 has been investigated by electron backscatter diffraction, X-ray and neutron diffraction. The influence of orientation on the predominant Deformation mechanisms and on the recovery processes taking place during Deformation has been systematically examined. The results have been compared with those corresponding to the same alloy tested quasi-statically under equivalent conditions. It has been found that strain rate enhances the activation of { 1 0 1 ¯ 2 } extension twinning dramatically, while contraction and secondary twinning are not significantly influenced. The polarity of { 1 0 1 ¯ 2 } extension twinning is even reversed in some grains under selected testing conditions. Significant grain subdivision by the formation of geometrically necessary boundaries (GNBs) takes place during both quasi-static and Dynamic Deformation of this AZ31 alloy. It is remarkable that GNBs of high misorientations form even at the highest strain rates. The phenomenon of recovery has been found to be orientation dependent.
