Integrated Two-Dimensional Modeling of Fluid Flow and Compaction in a Sedimentary Basin     

Zhangxin Chen  Richard E. Ewing  Hao Lu  Stephen L. Lyons  Serguei Maliassov  Michael B. Ray  Tong Sun 《Computational Geosciences》2002,6(3-4):545-564

In this paper we employ mixed finite elements and numerically study an integrated two-dimensional model of fluid flow and compaction in a sedimentary basin. This model describes a single phase incompressible flow in a two-dimensional section of a sedimentary basin with vertical compaction. At each time step, an iterative algorithm is used to solve this model. The determination of the grid movement is based on the mass conservation and movement of sediments in the basin, while the mixed method is utilized to solve the fluid flow over the moving grid. Numerical experiments are presented to verify this iterative algorithm and show representative solutions for the model under consideration.  相似文献   

Dublin days: the 2003 NAM     

Mark E Bailey  Tom Ray 《Astronomy& Geophysics》2003,44(3):3.07-3.08

Mark E Bailey and Tom Ray give an overview of the National Astronomy Meeting in Dublin, where record numbers of astronomers went to talk, listen and network.  相似文献   

A Local Example of Land‐Use Change: Southern Illinois—1807, 1938, and 1993*     

Leslie A. Duram  Jon Bathgate  Christina Ray 《The Professional geographer》2004,56(1):127-140

This article provides an analysis of a wetland site in southern Illinois from presettlement to the present. The study area is part of the Cache River‐Cypress Creek Wetland, which has international importance, as recognized by the Ramsar Convention on Wetlands. Land‐cover data for 1807, 1938, and 1993 were created and analyzed with a geographic information system (GIS). Land‐use change by topographic setting (uplands, transitional, and bottomlands) and soil productivity was quantified and studied. Interviews with local experts informed this analysis. Results illustrate the complexity of environmental change and its driving forces. First, notable forest and swamp acreage was converted to cropland between 1807 and 1938 and, to a lesser degree, from 1938 to 1993. Second, there were land‐use variations by topographic region. Between 1807 and 1938, the largest transformation occurred in the uplands, with substantial acreage converted from forest to cropland. Between 1938 and 1993, however, agriculture decreased in the upland areas as hilly areas reverted to forest cover. At the same time, agriculture expanded in the bottomlands as this land was drained for farming. Third, there are interesting patterns within these categories of land‐use change, as soil productivity is an indicator of what lands were taken out of cropland and converted back to grassland and forest.  相似文献   

40Ar/39Ar geochronology of subaerial lava flows of Barren Island volcano and the deep crust beneath the Andaman Island Arc,Burma Microplate     

Jyotiranjan S. Ray  Kanchan Pande  Rajneesh Bhutani 《Bulletin of Volcanology》2015,77(6):1-10

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Charged isotropic model with conformal symmetry     

D. Kileba Matondo  S. D. Maharaj  S. Ray 《Astrophysics and Space Science》2018,363(9):187

We investigate the behaviour of a charged isotropic model with conformal symmetry. The relationship between the gravitational potentials arising from the conformal condition is used to generate a new class of exact solutions to the Einstein-Maxwell equations. A specific form of the electric field intensity and the metric potential is required to avoid a singularity at the centre. We can find simple elementary functions for the matter variables and the potentials with realistic profiles. The causality conditions, stability conditions and energy conditions are satisfied. Masses, radii, central densities and surface redshifts are generated, and the values are consistent with the compact stars 4U 1538-52 and PSR J1614-2230.  相似文献   

Modeling regional landslide susceptibility using dynamic soil moisture profiles     

Ram L. Ray  Jennifer M. Jacobs  Ellen M. Douglas 《山地科学学报》2018,15(8):1807-1824

A landslide susceptibility mapping study was performed using dynamic hillslope hydrology. The modified infinite slope stability model that directly includes vadose zone soil moisture (SM) was applied at Cleveland Corral, California, US and Krishnabhir, Dhading, Nepal. The variable infiltration capacity (VIC-3L) model simulated vadose zone soil moisture and the wetness index hydrologic model simulated groundwater (GW). The GW model predictions had a 75% NASH-Sutcliffe efficiency when compared to California’s in-situ GW measurements. The model performed best during the wet season. Using predicted GW and VIC-3L vadose zone SM, the developed landslide susceptibility maps showed very good agreement with mapped landslides at each study region. Previous quasi-dynamic model predictions of Nepal’s hazardous areas during extreme rainfall events were enhanced to improve the spatial characterization and provide the timing of hazardous conditions.  相似文献   

Estimation of flood damage functions for river basin planning: a case study in Bangladesh     

Y. C. Ethan Yang  Patrick A. Ray  Casey M. Brown  Abedalrazq F. Khalil  Winston H. Yu 《Natural Hazards》2015,75(3):2773-2791

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Experimental studies to constrain parental magma of Malangtoli volcanics from Singhbhum craton of the eastern Indian shield     

Mousumi Banerjee  Jyotisankar Ray  Nupur Adhikary  Sandip Nandy  C. Manikyamba  Madhuparna Paul  Dola Chakraborty  Alireza Eslami 《Journal of the Geological Society of India》2016,88(2):245-255

Malangtoli volcanics of the Singhbhum craton of the eastern Indian shield is one of the important Proterozoic lava suites. Experimental studies on 1 atmosphere pressure constrain the parental magma type and temperature range of crystallization of the parent magma (deduced to be in the range of 1500°C to 1200°C). The experimental studies show that at 1500°C, plagioclase is the first phase to crystallize, followed by few opaques which join along with plagioclase at 1450°C. At subsequent lower temperature (1400°C-1300°C), plagioclase and opaque continue to crystallize. At 1250°C plagioclase and opaque still persist while pyroxene appears first and liquid (glass) still remains. Appearance of opaque minerals (magnetite and illmenite) at both ~1400°C and ~1300°C indicate oscillation of oxygen fugacity in the parent magma, petrographically documented by coarser phenocrysts as well as finer or peripheral tiny grains. Use of tectonic discrimination diagrams (based on discrimination factors F₁-F₂ and FeO^t/MgO vs. TiO₂) shows an island arc tholeiitic affinity for Malangtoli volcanic, suggests that the role of proto-plate convergence in Singhbhum architecture played an important role to build up Malangtoli volcanics during Proterozoic.  相似文献   

Response of low‐angle dunes to variable flow          下载免费PDF全文

Megan L. Hendershot  Jeremy G. Venditti  Ryan W. Bradley  Ray A. Kostaschuk  Michael Church  Mead A. Allison 《Sedimentology》2016,63(3):743-760

Current understanding of bedform dynamics is largely based on field and laboratory observations of bedforms in steady flow environments. There are relatively few investigations of bedforms in flows dominated by unsteadiness associated with rapidly changing flows or tides. As a consequence, the ability to predict bedform response to variable flow is rudimentary. Using high‐resolution multibeam bathymetric data, this study explores the dynamics of a dune field developed by tidally modulated, fluvially dominated flow in the Fraser River Estuary, British Columbia, Canada. The dunes were dominantly low lee angle features characteristic of large, deep river channels. Data were collected over a field ca 1·0 km long and 0·5 km wide through a complete diurnal tidal cycle during the rising limb of the hydrograph immediately prior to peak freshet, yielding the most comprehensive characterization of low‐angle dunes ever reported. The data show that bedform height and lee angle slope respond to variable flow by declining as the tide ebbs, then increasing as the tide rises and the flow velocities decrease. Bedform lengths do not appear to respond to the changes in velocity caused by the tides. Changes in the bedform height and lee angle have a counterclockwise hysteresis with mean flow velocity, indicating that changes in the bedform geometry lag changes in the flow. The data reveal that lee angle slope responds directly to suspended sediment concentration, supporting previous speculation that low‐angle dune morphology is maintained by erosion of the dune stoss and crest at high flow, and deposition of that material in the dune trough.  相似文献   

Has the Largest Field Been Discovered Yet? PETRIMES and GRASP 25 Years Later     

Gordon M. Kaufman  Ray Faith  John H. Schuenemeyer 《Mathematical Geosciences》2016,48(8):873-890

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