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1.
A numerical scheme is developed in order to simulate fluid flow in three dimensional (3‐D) microstructures. The governing equations for steady incompressible flow are solved using the semi‐implicit method for pressure‐linked equations (SIMPLE) finite difference scheme within a non‐staggered grid system that represents the 3‐D microstructure. This system allows solving the governing equations using only one computational cell. The numerical scheme is verified through simulating fluid flow in idealized 3‐D microstructures with known closed form solutions for permeability. The numerical factors affecting the solution in terms of convergence and accuracy are also discussed. These factors include the resolution of the analysed microstructure and the truncation criterion. Fluid flow in 2‐D X‐ray computed tomography (CT) images of real porous media microstructure is also simulated using this numerical model. These real microstructures include field cores of asphalt mixes, laboratory linear kneading compactor (LKC) specimens, and laboratory Superpave gyratory compactor (SGC) specimens. The numerical results for the permeability of the real microstructures are compared with the results from closed form solutions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
3.
Al. A. Suchkov 《Astrophysics》1985,23(1):452-458
4.
Multivariate analysis of heavy metal contents of sediments from Gumusler creek, Nigde, Turkey 总被引:2,自引:0,他引:2
In this study, heavy metal contents of samples from Gumusler creek in Turkey were studied and the metal contamination characteristics
were investigated. In this respect, considering the pollutant sites in the area, systematic sediment samples were collected
in a zone starting from the manifestation part of the water to the entrance of the Karasu creek in Gumusler town. Samples
were taken from lower section of the river bed at 30 stations along Gumusler creek, 13 km in length and their heavy metal
contents were analyzed with XRF Spectrometer. Correlation coefficients, element coefitic coefficient correlation, dendogram
hierarchical cluster, model summary and Annova analysis statistical methods were applied to data. Strong positive correlations
were determined for some elements which are believed to have possibly the same origin. In addition, mineralizations in the
area are thought to cause variation in metal contents. Results of chemical analysis show that soil limit values and clark
values were exceeded. The heavy metal accumulation in the creek is believed to be derived from non-operated Sb-Hg-W and Fe
quarries. 相似文献
5.
The Ras Al-Subiyah area is considered one of the most promising areas in Kuwait for future development. This development will
include a new town called Subiyah and its associated infrastructure. This area is also being considered as the location for
connection between Boubyan Island, which is now undergoing major development and the Kuwait mainland. The present study investigates
the geomorphology of the Ras Al-Sabiyah area in the northern sector of Kuwait. The study area is generally flat, and it is
located west of the Jal Az-Zor escarpment. It is bordered on the east by the Khor Al-Sabiyah tidal channel and on the south
by Kuwait Bay. The area receives sediments from several sources; currently the most important are aeolian sediments and the
deposition of mud delivered through the Khor Al-Sabiyah from the Iraqi marshes. The study area has been subjected to severe
environmental changes due to the Gulf wars and the drainage of Iraqi marshes and the associated artificial changes in fluvial
system. Twenty-two surface sediments were collected from the Ras Al-Subiyah area. Samples were collected to include the main
geomorphologic characteristic features of the study area. Field observations and remote sensing images from 1990 and 2001
were used to produce an updated geomorphologic map for the Ras Al-Subiyah and a map showing geomorphic changes between 1990
and 2001. Grain size of the surface sediment ranges from gravel to medium sand. In general, grain size statistical analysis
indicates that most of the areas are composed of two or more classes of sands transported and deposited from different sources
including aeolian, sabkhas, river and the bays. The variability in the grain size statistical parameters may be attributed
to the complexity of surface morphology as well as the diversity in the type of depositional environment in the Ras Al-Subiyah
area. The total area subjected to change during the 12-year period (1990–2001) is about 32 km2 as calculated using GIS techniques. 相似文献
6.
There could be some discontinuities in a soil media such as layers, earth structures, cracks, and fissures so that estimation
of stresses and deformations in these types of soil masses are somewhat different from continuous masses. The discontinuities
in a soil mass could be considered as a special link between two blocks. Transmitted swelling pressures affected by the soil
properties of the backfill especially at the interface between the backfill and retaining wall. In order to estimate the transmitted
swelling pressure distribution behind a retaining wall, using with interface element, a new finite element model and a code
(SWELPRES) have been developed. To evaluate the effect of backfill characteristics and interface element from the transmitted
lateral swelling pressures, four cases of thickness of backfills with or without interface elements are investigated. 相似文献
7.
A. A. Schreider Al. A. Schreider A. A. Bulychev J. Galindo-Zaldivar A. Maldonado G. L. Kashintsev 《Oceanology》2006,46(1):114-122
A new map of chrons for the American-Antarctic Ridge area has been compiled. Its analysis and the calculations performed showed that the seafloor spreading with respect to its axis started before 85 My B.P. The spreading directions were 115° (chrons C34-C29), 145° (chrons C29-C21), 110° (chrons C21-C5C), and 85° (chrons C5C-C1). The maximum rates of about 4 cm/year were reached earlier than 52 My B.P.; subsequently, a progressive general decrease in the spreading rate has been observed. According to our forecast, the spreading may cease in the following 3.5 My. 相似文献
8.
Erdal Dolu Erkan Gökaşan Engin Meriç Mustafa Ergin Tolga Görüm Hüseyin Tur Berkan Ecevitoğlu Niyazi Avşar Muhittin Görmüş Fatmagül Batuk Buğser Tok Oktay Çetin 《Geo-Marine Letters》2007,27(6):355-381
The Quaternary evolution of the Gulf of İzmit, situated on the tectonically active North Anatolian Fault Zone (NAFZ), was
investigated using seismic reflection, paleontologic, and sediment textural data. On the basis of seismic stratigraphic and
sedimentologic-paleontologic interpretations, four depositional units were distinguished within the Plio-Quaternary sequence
of the Gulf of İzmit. According to these data, Plio-Quaternary deposits supplied from the northern terrestrial area started
to accumulate during a progradational phase, in a south-facing half-graben. A coarse-grained sedimentary unit prograding into
the gulf from the south since 200 ka b.p. indicates a dramatic variation in the evolution of the gulf, with the initiation of a new strike-slip fault of the NAFZ
and a corresponding uplift of the Armutlu Peninsula in the south of the gulf. During the evolution of this fault from a wide
shear zone consisting of right-stepped strike-slip faults and pull-apart basins to a localized principal fault zone, sediments
were deposited under the influence of northerly prograding terrestrial and shallow-marine conditions due to relative sea-level
fluctuations in the Marmara Sea. During this period, the Gulf of İzmit was invaded mainly by Mediterranean and partly by Black
Sea waters. In the latest glacial period, shallow areas in the gulf became subaerially exposed, whereas the central and western
sub-basins of the gulf turned into lakes. The present evolution of the Gulf of İzmit is controlled by the after effects of
the new rupture of the NAFZ and the estuarine nature of the gulf environment. 相似文献
9.
Until recently, the ideas about the age of the Black Sea deep-water basin have been based on land geological observations in the coastal areas at the interaction periphery, underwater observations from manned submersibles, and on the data of seismic reflection and refraction studies and drilling. Formerly, the scarcity of the information led to a wide scattering of the age determinations: from the Jurassic to the Eocene. Recently, with the appearance of reliable geological and geophysical data, the range of the age estimates has been considerably reduced during the last few years, although there is no commonly accepted opinion on this issue. Therefore, the first attempt to determine the age of the Western Black Sea basin using an analysis of the anomalous magnetic field is of certain interest. The following results were obtained: the basin probably opened between 71.338 and 71.587 My B.P. (subchron C32n.1r). During the interval 68.737–71.071 My B.P. (subchron C31r), extinction of the spreading axes took place. Thus, the total duration of the Campanian-Maestrichtian phase of the opening was about 3 My (interval from 71.587 to 68.737 My B.P.). This result does not agree with the geological and geophysical data available to date. To solve this problem, collection of new geological data and further studies of the structure of the anomalous magnetic field are required. 相似文献
10.
K. S. Rao Y. S. Rao H. K. Al Jassar 《Journal of the Indian Society of Remote Sensing》2008,36(2):123-136
Spaceborne Imaging Radar (SIR-C) data acquired over Gujarat, India in 1994 were processed and analysed using differnet techniques
applicable to polarimetric SAR data such as polarization signatures, polarization index, decomposition of the signal and polarization
phase difference and limited groundtruth data. It has been observed that multi-frequency polarimetric data enhances the potential
of retrieving geo-physical parameters. The polarization signatures are found to vary with the nature of the target. Target
decomposition of the returned signal will be useful for the classification of various features. Polarization Phase Difference
(PPD) gives good information about the vegetation parameters. 相似文献