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Prognosis of TiO2 abundance in lunar soil using a non-linear analysis of Clementine and LSCC data 总被引：1，自引：0，他引：1
Viktor V. Korokhin Vadym G. Kaydash Dmitry G. Stankevich 《Planetary and Space Science》2008,56(8):1063-1078
We suggest a technique to determine the chemical and mineral composition of the lunar surface using artificial neural networks (ANNs). We demonstrate this powerful non-linear approach for prognosis of TiO2 abundance using Clementine UV-VIS mosaics and Lunar Soil Characterization Consortium data. The ANN technique allows one to study correlations between spectral characteristics of lunar soils and composition parameters without any restrictions on the character of these correlations. The advantage of this method in comparison with the traditional linear regression method and the Lucey et al. approaches is shown. The results obtained could be useful for the strategy of analyzing lunar data that will be acquired in incoming lunar missions especially in case of the Chandrayaan-1 and Lunar Reconnaissance Orbiter missions. 相似文献
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Phase-ratio imagery is a new tool of qualitative photometric analyses of the upper layer of the lunar regolith, which allows the identification of natural surface structure anomalies and artificially altered regolith. We apply phase-ratio imagery to analyze the Apollo-14, -15, and -17 landing sites. This reveals photometric anomalies of ∼170 × 120 m size that are characterized by lower values of the phase-function steepness, indicating a smoothing of the surface microstructure caused by the engine jets of the landing modules. Other photometric anomalies characterized by higher phase-function slopes are the result of regolith loosening by astronaut boots and the wheels of the Modular Equipment Transporter and the Lunar Roving Vehicle. We also provide a possible explanation for the high brightness of the wheel tracks seen in on-surface images acquired at very large phase angles. 相似文献
3.
We established an equation of state for nanocrystalline forsterite using multi-anvil press and diamond anvil cell. Comparative
high-pressure and high-temperature experiments have been performed up to 9.6 GPa and 1,300°C. We found that nanocrystalline
forsterite is more compressible than macro-powder forsterite. The bulk modulus of nanocrystalline forsterite is equal to 123.3
(±3.4) GPa whereas the bulk modulus of macro-powder forsterite is equal to 129.6 (±3.2) GPa. This difference is attributed
to a weakening of the elastic properties of grain boundary and triple junction and their significant contribution in nanocrystalline
sample compare to the bulk counterpart. The bulk modulus at zero pressure of forsterite grain boundary was determined to be
83.5 GPa. 相似文献
4.
Vadym Aizinger Jennifer Proft Clint Dawson Dharhas Pothina Solomon Negusse 《Ocean Dynamics》2013,63(1):89-113
In this work, we present results of a numerical study of Corpus Christi Bay, Texas and surrounding regions and compare simulated model results to recorded data. The validation data for the year 2000 include the water elevation, velocity, and salinity at selected locations. The baroclinic computations were performed using the University of Texas Bays and Estuaries 3D (UTBEST3D) simulator based on a discontinuous Galerkin finite element method for unstructured prismatic meshes. We also detail some recent advances in the modeling capabilities of UTBEST3D, such as a novel turbulence scheme and the support for local vertical discretization on parts of the computational domain. All runs were conducted on parallel clusters; an evaluation of parallel performance of UTBEST3D is included. 相似文献
5.
In this paper, we continue our analysis of upwind‐mixed methods for advection–diffusion equations, which have been developed
and analyzed by the first author over the past several years. In previous work, our analysis has been limited to low order
approximating spaces, positive definite diffusion coefficients and Dirichlet boundary conditions. In this paper, we extend
our results to higher order approximating spaces, possibly zero diffusion, and more physically realistic boundary conditions.
Moreover, unlike previous papers, we avoid the use of Gronwall's Inequality, which can result in extremely large constants
in the stability and error bounds. Numerical results are presented for constant, linear and quadratic approximating spaces.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Viktor V. Korokhin Yuriy I. Velikodsky Yuriy G. Shkuratov Vadym G. Kaydash Sergey Y. Gerasimenko Nikolai V. Opanasenko Gorden Videen Carle Pieters 《Planetary and Space Science》2010,58(10):1298-1306
Lunar images acquired at non-zero phase angles show brightness variations caused by both albedo heterogeneities and local topographic slopes of the surface. To distinguish between these two factors, altimetry measurements or photoclinometry data can be used. The distinction is especially important for imagery of phase-function parameters of the Moon. The imagery is a new tool that can be used to study structural anomalies of the lunar surface. To illustrate the removal of the topographic effects from photometric images, we used Earth-based telescopic observations, altimetry measurements carried out with the Kaguya (JAXA) LALT instrument, and a new photoclinometry technique that includes analysis of several images of the same scenes acquired at different phase angles. Using this technique we have mapped the longitudinal component of lunar topography slopes (the component measured along the lines of constant latitude). We have found good correlations when comparing our map with the corresponding data from Kaguya altimetry. The removal of the topographic surface properties allows for the study of the phase-function parameters of the lunar surface, not only for flat mare regions, but for highlands as well. 相似文献
7.
Vadym Aizinger Andreas Rupp Jochen Schütz Peter Knabner 《Computational Geosciences》2018,22(1):179-194
We present an a priori stability and convergence analysis of a new mixed discontinuous Galerkin scheme applied to the instationary Darcy problem. The analysis accounts for a spatially and temporally varying permeability tensor in all estimates. The proposed method is stabilized using penalty terms in the primary and the flux unknowns. 相似文献
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Alex Shevchenko Vadym Gudzenko Igor Nasedkin Edward Panasevitch 《Environmental Geology》2001,40(10):1177-1184
The left bank of the Pripiat' river, opposite of the Chernobyl Nuclear Power Plant (ChNPP) is covered with a developed network of drainage canals, built for the reclamation of the swampy floodplain. This area is highly contaminated after the disaster in 1986. Concentrations of the most mobile radionuclide, 90Sr, are comparable with 137Cs, and reach many MBq m-2. Their ratio in the upper 10 cm of soil is about 1. The high surface contamination as well as precipitation and flooding have been responsible for the water pollution in this area. Some specifics of 90Sr behaviour in surface and groundwater, controlled by the hydrological regime, are described. 相似文献
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