Groundwater occurrence and flow pattern in the Enugu coal-mine area,Anambra State,Nigeria     

G. I. NWANKWOR  B. C. EGBOKA  I. P. ORAJAKA 《水文科学杂志》2013,58(5):465-482

Abstract

The distribution of major geological units, static water level data, water chemistry data, and observations of surface features influenced by groundwater seepage were used to ascertain the nature of groundwater occurrence and flow pattern in the Enugu coal field, Nigeria. Considerations of the geological units, the static groundwater levels and groundwater seepages in the mines indicate that the coal sequence is a multiaquifer system in which sandstone and coal aquifers alternate with shale aquitards. Based on the hydraulic head data, the groundwater flow is predominantly downwards. Groundwater velocity calculation across the multiaquifer system using the Darcy equation gave a flow velocity of about 1 m day^?1. For groundwater systems, such a calculated velocity is considered high. The high velocity is most probably due to the high fracture porosity as well as the presence of other stratigraphic and structural features such as alluvial fills that provide high hydraulic conductivity pathways across the aquifer system. The pattern of groundwater inflow into the mines is also influenced by these stratigraphie and structural features.  相似文献   

Using psychophysiological indices to estimate the effect of cosmophysical factors (Review)     

N. I. Khorseva 《Izvestiya Atmospheric and Oceanic Physics》2013,49(8):839-852

This review first summarizes estimates of the functional response of the central nervous system (CNS) to variations in cosmophysical factors using different psychophysiological indices (electrical activity of the brain, sensorimotor and motor reactions, and higher mental functions such as attention and memory). We analyze the applicability of information technologies to record different physiological parameters.  相似文献   

U-Pb ages of detrital zircons from modern sediments of the Yangtze River and stages of orogeny in Southeast Asia   总被引：1，自引：0，他引：1  

I. Yu. Safonova  Sh. Rino  Sh. Maruyama 《Doklady Earth Sciences》2010,431(1):280-284

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On the magnetic field diffusion in mhd modeling of the inner coma of comet halley     

M. D. Kartalev  V. I. Nikolova 《地球物理与天体物理流体动力学》2013,107(1-2):145-168

Abstract

Some approaches of one-dimensional time-dependent magneto-hydrodynamic modeling of the structure of the inner coma of comet Halley are considered. The influence of the magnetic field diffusion on this structure is studied. The solution of Cravens (1989) approach containing classic magnetic diffusion is compared with an approach containing a specific diffusion, caused by non-instantaneous mass-loading of new ions. A case with no magnetic field is also considered. Common features of all the solutions are obtained. Special attention is paid to the sharp velocity jump, synchronized with a local density pick. Some differences between two types of magnetic field diffusion are discussed. A possible connection is supposed between this consideration and the large-scale shock fitting modeling of the solar plasma-comet interaction.  相似文献   

Multifractal behaviour of long‐term karstic discharge fluctuations     

D. Labat  C. T. Hoang  J. Masbou  A. Mangin  I. Tchiguirinskaia  S. Lovejoy  D. Schertzer 《水文研究》2013,27(25):3708-3717

Karstic watersheds are highly complex hydrogeological systems that are characterized by a multiscale behaviour corresponding to the different pathways of water in these systems. The main issue of karstic spring discharge fluctuations consists in the presence and the identification of characteristic time scales in the discharge time series. To identify and characterize these dynamics, we acquired, for many years at the outlet of two karstic watersheds in South of France, discharge data at 3‐mn, 30‐mn and daily sampling rate. These hydrological records constitute to our knowledge the longest uninterrupted discharge time series available at these sampling rates. The analysis of the hydrological records at different levels of detail leads to a natural scale analysis of these time series in a multifractal framework. From a universal class of multifractal models based on cascade multiplicative processes, the time series first highlights two cut‐off scales around 1 and 16 h that correspond to distinct responses of the aquifer drainage system. Then we provide estimates of the multifractal parameters α and C₁ and the moment of divergence q_D corresponding to the behaviour of karstic systems. These results constitute the first estimates of the multifractal characteristics of karstic spingflows based on 10 years of high‐resolution discharge time series and should lead to several improvements in rainfall‐karstic springflow simulation models. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

An indirect lead isotope age determination of gold mineralization at the Corinthia mine,Yilgarn Block,Western Australia     

E. J. M. Bloem  N. J. McNaughton  D. I. Groves  J. R. Ridley 《Australian Journal of Earth Sciences》2013,60(5):447-451

The Corinthia lode‐gold deposit in amphibolite‐facies greenstone belt rocks in the Southern Cross Province of the Archaean Yilgarn Block contains a largely undeformed pegmatite dyke emplaced during the last phases of movement along the Fraser's‐Corinthia shear zone. Gold mineralization and shear zone development were synchronous, and a Pb‐Pb isochron age of 2620 ±6 Ma for pegmatite emplacement either indirectly dates mineralization, or places a minimum age constraint on the timing of mineralization. This age is in accord with a broadly synchronous dominant episode of Archaean lode‐gold mineralization throughout the Yilgarn Block.  相似文献   

On the Mean Flow Behaviour in the Presence of Regional-Scale Surface Roughness Heterogeneity   总被引：2，自引：2，他引：0  

Xiang I. A. Yang 《Boundary-Layer Meteorology》2016,161(1):127-143

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MAPPING AND ASSESSMENT OF WATER POLLUTION IN IRKUTSK OBLAST     

A. I. Aseyeva 《地理信息系统科学与遥感》2013,50(1)

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Operational applications of remote sensing in hydrology: success,prospects and problems     

ALBERT RANGO  AHLAM I. SHALABY 《水文科学杂志》2013,58(6):947-968

Abstract

The use of remote sensing information in operational hydrology is relatively limited, but specific examples can be cited for determining precipitation, soil moisture, groundwater, snow, surface water and basin characteristics. The application of remote sensing in hydrology can be termed operational if at least one of two conditions are met: (a) the application produces an output on a regular basis, or (b) the remote sensing data are used regularly on a continuing basis as part of a procedure to solve a problem or make decisions. When surveying the various operational applications, simple approaches and simple remote sensing data sets are the most successful. In the data-sparse developing countries, many operational remote sensing approaches exist (out of necessity) that may not be needed in developed countries because of existing data networks. To increase the use of remote sensing in operational hydrology in developed countries, pilot projects need to be increased and information services must be improved. Increased utilization of GIS to combine remote sensing with other information will promote new products and applications. End user training must be improved by focusing on satellite data processing and manipulation. In developing countries the same improvements are needed plus some more basic ones. There is a need for international monetary assistance to establish long-term remote sensing data, improved database systems and image processing capabilities. There is also the need to set up innovative regional training centres throughout the developing world.  相似文献   

Dynamics of unsaturated poroelastic solids at finite strain     

Ryosuke Uzuoka  Ronaldo I. Borja 《国际地质力学数值与分析法杂志》2012,36(13):1535-1573

We derive the governing equations for the dynamic response of unsaturated poroelastic solids at finite strain. We obtain simplified governing equations from the complete coupled formulation by neglecting the material time derivative of the relative velocities and the advection terms of the pore fluids relative to the solid skeleton, leading to a so‐called u^s ? p^w ? p^a formulation. We impose the weak forms of the momentum and mass balance equations at the current configuration and implement the framework numerically using a mixed finite element formulation. We verify the proposed method through comparison with analytical solutions and experiments of quasi‐static processes. We use a neo‐Hookean hyperelastic constitutive model for the solid matrix and demonstrate, through numerical examples, the impact of large deformation on the dynamic response of unsaturated poroelastic solids under a variety of loading conditions. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献