The Experts below are selected from a list of 1626 Experts worldwide ranked by ideXlab platform
Raffaella Noschese - One of the best experts on this subject based on the ideXlab platform.
-
Radar sounding of Lucus Planum, Mars, by MARSIS
Journal of Geophysical Research: Planets, 2017Co-Authors: Roberto Orosei, Angelo Pio Rossi, Federico Cantini, Graziella Caprarelli, Lynn M. Carter, Irene Papiano, Marco Cartacci, Andrea Cicchetti, Raffaella NoscheseAbstract:Lucus Planum, extending for a radius of approximately 500 km around 181° E, 5° S, is part of the Medusae Fossae Formation (MFF), a set of several discontinuous deposits of fine-grained, Friable Material straddling across the Martian highland-lowland boundary. The MFF has been variously hypothesized to consist of pyroclastic flows, pyroclastic airfall, paleopolar deposits, or atmospherically-deposited icy dust driven by climate cycles. MARSIS, a low-frequency subsurface-sounding radar carried by ESA's Mars Express, acquired 238 radar swaths across Lucus Planum, providing sufficient coverage for the study of its internal structure and dielectric properties. Subsurface reflections were found only in three areas, marked by a distinctive surface morphology, while the central part of Lucus Planum appears to be made of radar-attenuating Material preventing the detection of basal echoes. The bulk dielectric properties of these areas were estimated and compared with those of volcanic rocks and ice-dust mixtures. Previous interpretations that east Lucus Planum and the deposits on the north-western flanks of Apollinaris Patera consist of high-porosity pyroclastic Material are strongly supported by the new results. The north-western part of Lucus Planum is likely to be much less porous, although interpretations about the nature of the subsurface Materials are not conclusive. The exact origin of the deposits cannot be constrained by radar data alone, but our results for east Lucus Planum are consistent with an overall pyroclastic origin, likely linked to Tharsis Hesperian and Amazonian activity.
Roberto Orosei - One of the best experts on this subject based on the ideXlab platform.
-
Radar sounding of Lucus Planum, Mars, by MARSIS
Journal of Geophysical Research: Planets, 2017Co-Authors: Roberto Orosei, Angelo Pio Rossi, Federico Cantini, Graziella Caprarelli, Lynn M. Carter, Irene Papiano, Marco Cartacci, Andrea Cicchetti, Raffaella NoscheseAbstract:Lucus Planum, extending for a radius of approximately 500 km around 181° E, 5° S, is part of the Medusae Fossae Formation (MFF), a set of several discontinuous deposits of fine-grained, Friable Material straddling across the Martian highland-lowland boundary. The MFF has been variously hypothesized to consist of pyroclastic flows, pyroclastic airfall, paleopolar deposits, or atmospherically-deposited icy dust driven by climate cycles. MARSIS, a low-frequency subsurface-sounding radar carried by ESA's Mars Express, acquired 238 radar swaths across Lucus Planum, providing sufficient coverage for the study of its internal structure and dielectric properties. Subsurface reflections were found only in three areas, marked by a distinctive surface morphology, while the central part of Lucus Planum appears to be made of radar-attenuating Material preventing the detection of basal echoes. The bulk dielectric properties of these areas were estimated and compared with those of volcanic rocks and ice-dust mixtures. Previous interpretations that east Lucus Planum and the deposits on the north-western flanks of Apollinaris Patera consist of high-porosity pyroclastic Material are strongly supported by the new results. The north-western part of Lucus Planum is likely to be much less porous, although interpretations about the nature of the subsurface Materials are not conclusive. The exact origin of the deposits cannot be constrained by radar data alone, but our results for east Lucus Planum are consistent with an overall pyroclastic origin, likely linked to Tharsis Hesperian and Amazonian activity.
Mark E. Smith - One of the best experts on this subject based on the ideXlab platform.
-
Magnesium analogues of aluminosilicate inorganic polymers (geopolymers) from magnesium minerals
Journal of Materials Science, 2012Co-Authors: Kenneth J. D. Mackenzie, Siobhan J. Bradley, John V. Hanna, Mark E. SmithAbstract:Attempts to synthesise magnesium-containing analogues of aluminosilicate geopolymers from the 1:1 and 2:1 layer magnesiosilicate minerals chrysotile and talc, as well as the magnesium mineral sepiolite are reported. The effect of pre-treating these starting minerals by grinding and/or dehydroxylation was also investigated by XRD, 29Si and natural-abundance 25Mg solid-state magic angle spinning (MAS) NMR spectroscopy. The products from sepiolite most closely resembled an aluminosilicate geopolymer, setting at 40 °C to an X-ray amorphous product containing a broad characteristic 29Si MAS NMR resonance at −90 ppm. The 25Mg MAS NMR spectrum of this product also showed evidence that some of the Mg was located in tetrahedral sites, as expected for a conventional geopolymer. A similar 25Mg MAS NMR result was obtained for chrysotile, but talc proved to be extremely resistant to geopolymer synthesis, requiring treatment at 120 °C for 3 days to set to a Friable Material retaining the XRD and NMR characteristics of the original talc or its crystalline dehydroxylation products. This lack of reactivity may be related to the 2:1 layer-lattice talc structure, or to the fact that a suitably reactive amorphous product is not formed upon dehydroxylation.
Angelo Pio Rossi - One of the best experts on this subject based on the ideXlab platform.
-
Radar sounding of Lucus Planum, Mars, by MARSIS
Journal of Geophysical Research: Planets, 2017Co-Authors: Roberto Orosei, Angelo Pio Rossi, Federico Cantini, Graziella Caprarelli, Lynn M. Carter, Irene Papiano, Marco Cartacci, Andrea Cicchetti, Raffaella NoscheseAbstract:Lucus Planum, extending for a radius of approximately 500 km around 181° E, 5° S, is part of the Medusae Fossae Formation (MFF), a set of several discontinuous deposits of fine-grained, Friable Material straddling across the Martian highland-lowland boundary. The MFF has been variously hypothesized to consist of pyroclastic flows, pyroclastic airfall, paleopolar deposits, or atmospherically-deposited icy dust driven by climate cycles. MARSIS, a low-frequency subsurface-sounding radar carried by ESA's Mars Express, acquired 238 radar swaths across Lucus Planum, providing sufficient coverage for the study of its internal structure and dielectric properties. Subsurface reflections were found only in three areas, marked by a distinctive surface morphology, while the central part of Lucus Planum appears to be made of radar-attenuating Material preventing the detection of basal echoes. The bulk dielectric properties of these areas were estimated and compared with those of volcanic rocks and ice-dust mixtures. Previous interpretations that east Lucus Planum and the deposits on the north-western flanks of Apollinaris Patera consist of high-porosity pyroclastic Material are strongly supported by the new results. The north-western part of Lucus Planum is likely to be much less porous, although interpretations about the nature of the subsurface Materials are not conclusive. The exact origin of the deposits cannot be constrained by radar data alone, but our results for east Lucus Planum are consistent with an overall pyroclastic origin, likely linked to Tharsis Hesperian and Amazonian activity.
Graziella Caprarelli - One of the best experts on this subject based on the ideXlab platform.
-
Radar sounding of Lucus Planum, Mars, by MARSIS
Journal of Geophysical Research: Planets, 2017Co-Authors: Roberto Orosei, Angelo Pio Rossi, Federico Cantini, Graziella Caprarelli, Lynn M. Carter, Irene Papiano, Marco Cartacci, Andrea Cicchetti, Raffaella NoscheseAbstract:Lucus Planum, extending for a radius of approximately 500 km around 181° E, 5° S, is part of the Medusae Fossae Formation (MFF), a set of several discontinuous deposits of fine-grained, Friable Material straddling across the Martian highland-lowland boundary. The MFF has been variously hypothesized to consist of pyroclastic flows, pyroclastic airfall, paleopolar deposits, or atmospherically-deposited icy dust driven by climate cycles. MARSIS, a low-frequency subsurface-sounding radar carried by ESA's Mars Express, acquired 238 radar swaths across Lucus Planum, providing sufficient coverage for the study of its internal structure and dielectric properties. Subsurface reflections were found only in three areas, marked by a distinctive surface morphology, while the central part of Lucus Planum appears to be made of radar-attenuating Material preventing the detection of basal echoes. The bulk dielectric properties of these areas were estimated and compared with those of volcanic rocks and ice-dust mixtures. Previous interpretations that east Lucus Planum and the deposits on the north-western flanks of Apollinaris Patera consist of high-porosity pyroclastic Material are strongly supported by the new results. The north-western part of Lucus Planum is likely to be much less porous, although interpretations about the nature of the subsurface Materials are not conclusive. The exact origin of the deposits cannot be constrained by radar data alone, but our results for east Lucus Planum are consistent with an overall pyroclastic origin, likely linked to Tharsis Hesperian and Amazonian activity.
