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991.
992.
Polymer injection is a widespread strategy in enhanced oil recovery. Polymer increases the water viscosity and creates a more favorable mobility ratio between the injected water and the displaced oil. The computational cost of simulating polymer injection can be significantly reduced if one splits the governing system of two-phase equations into a pressure equation and a set of saturation/component equations and use a Gauss–Seidel algorithm with optimal cell ordering to solve the nonlinear systems arising from an implicit discretization of the saturation/component equations. This approach relies on a robust single-cell solver that computes the saturation and polymer concentration of a cell, given the total flux and the saturation and polymer concentration of the neighboring cells. In this paper, we consider a relatively comprehensive polymer model used in an industry-standard simulator, and show that, in the case of a discretization using a two-point flux approximation, the single-cell problem always admits a solution that is also unique.  相似文献   
993.
Modeling geological carbon storage represents a new and substantial challenge for the subsurface geosciences. To increase understanding and make good engineering decisions, containment processes and large-scale storage operations must be simulated in a thousand-year perspective. Large differences in spatial and temporal scales make it prohibitively expensive to compute the fate of injected CO2 using traditional 3D simulators. Instead, accurate forecast can be computed using simplified models that are adapted to the specific setting of the bouyancy-driven migration of the light fluid phase. This paper presents a family of vertically integrated models for studying the combined large-scale and long-term effects of structural, residual, and solubility trapping of CO2. The models are based on an assumption of a sharp interface separating CO2 and brine and can provide a detailed inventory of the injected CO2 volumes over periods of thousands of years within reasonable computational time. To be compatible with simulation tools used in industry, the models are formulated in a black-oil framework. The models are implemented in MRST-co2lab, which is an open community software developed especially to study and optimize large-scale, long-term geological storage of CO2. The resulting simulators are fully implicit and handle input from standard geomodeling tools.  相似文献   
994.
Crucian carp were exposed to three combinations of pH and inorganic aluminium concentrations for 25 days. Mortality, plasma chloride and haematocrit, and gill aluminium content were investigated. No mortality was observed in any of the three exposures. Crucian carp survived acidic Al-rich water (pH 5.17) with a high concentration of low-molecular weight inorganic Al species (242 µgl–1) for 25 days. These fish had lowered plasma chloride levels and high amounts of aluminium on their gills compared to fish exposed to acidic Al-poor water (pH 5.16 and 12 µgl–1 Ali) and control water (pH 6.29 and 4 µgl–1 Ali). Haematocrit was the same in all three exposures. Because aluminium was not acutely toxic to the anoxia tolerant crucian carp, the present results give support to the hypothesis that Al polymerization with subsequent hypoxia is of high importance for the mechanism of acute Al toxicity to fish.  相似文献   
995.
Three new U-Pb zircon age determinations are reported from the Horred region, south-southeast of Göteborg, SW Sweden. This is a region of the Southwest Scandinavian Domain, within which a major NS trending shear zone and tectonic boundary, the Mylonite Zone, juxtaposes comparatively weakly migmatised lithologies in the west against more intensely migmatised gneisses in the east.West of the Mylonite Zone, a metavolcanic rock (the Mjösjödacite) yields an age of 1643 ± 29 Ma, whereas a cross-cutting plutonic rock (the Idala tonalite) has an age of 1584 ± 15 Ma. Together with a recent age for a volcanic rock from theÅmål region farther north (1.61 Ga, Lundqvist and Skiöld, 1992), these ages help to establish the existence of a coherent calc-alkaline igneous belt of 1.6 Ga age for which the nameÅmål-Horred Belt is proposed.East of the Mylonite Zone, a presumably metavolcanic rock (the Grimmared gneiss) yields an age of 1.61 Ga. The obtained age and the compositional similarity of rocks on each side of the Mylonite Zone indicate that more deformed and more strongly metamorphosed equivalents of the rocks in theÅmål-Horred Belt may occur also to the east of the Mylonite Zone in what is termed the Eastern Segment of the Southwest Scandinavian Domain.The new results establish theÅmål-Horred Belt as a major geological unit younger than most other crustal components in southern Sweden such as theÖstfold-Marstrand Belt ( 1.76 Ga), the Eastern Segment gneisses (> 1.66 Ga) and the three age groups of the Transscandinavian Igneous Belt ( 1.81 – 1.65 Ga; Larson and Berglund, 1992). The configuration of the crustal units in SW Sweden appears to necessitate more complex Proterozoic models than those with a persistent younging from the present east to the west.The present concept of the “Gothian orogeny” must be revised since at least two different orogenic episodes at 1.7 and 1.6 Ga can now be distinguished.  相似文献   
996.
High concentrations of mercury were measured in sediment and animals collected in the immediate vicinity of a closed-down chemical factory. Sediment contained up to 22 ppm (dry wt) of mercury, deposit-feeding bivalves between 1.4 and 4.4 ppm (wet wt), suspension-feeding bivalves between 0.9 and 1.9 ppm and predatory fish between 0.3 and 0.8 ppm. Outside the ‘hot spot’ area, the mercury concentration in sediment and mussels (Mytilus edulis) rapidly decreased with increasing distance from the former factory. Mercury concentration in flounders (Platichthys flesus) also decreased with distance from the source; the decline was, however, much less marked.  相似文献   
997.
Behavioural effects of marine sediment contaminated with pesticides (6000 ppm parathion, 200 ppm methyl parathion, 200 ppm malathion) were studied in a number of marine organisms in laboratory tests and in situ. The burrowing behaviour in Macoma baltica, Cerastoderma edule, Abra alba, Nereis diversicolor and Scoloplos armiger was impaired in the contaminated sediment compared to control. The impairment was most pronounced in the laboratory tests, where almost no burrowing occured. In a very simple laboratory set-up, highly significant avoidance of the contaminated sediment was demonstrated for Crangon crangon and Solea solea, but not for Carcinus meanas and Pomatoschistus minutus. The validity of both behavioural tests was supported by in situ observations and investigations on the distribution of the species. It is concluded that both tests are useful tools in the assessment of the impact of contaminated sediments.  相似文献   
998.
A simplified model is given which computes the wind distribution over an arbitrary mountain range for a given upwind boundary-layer profile. The method has been adopted for the HP-41C calculator and results include the distribution of the amplification factor along the wind direction for various topographies.  相似文献   
999.
Hypolimnetic oxygen in the highly eutrophic Swiss lake Greifensee (area 8 km2, maximum depth 33 m) was almost entirely depleted during summer stratification. We found a strong empirical relation between wind action across the lake surface and hypolimnetic reoxygenation in the cold half year. Long periods of ice cover severely limited anemogenic reoxygenation.   相似文献   
1000.
Major and trace element analyses of metabasalts from five of the Lower Palaeozoic Caledonian ophiolite fragments along a strike distance of some 800 km of the west Norwegian coast are presented. Characteristically the REE patterns show depletion of both LREE and HREE relative to intermediate REE, giving an upward convex shape, but nearly flat, LREE depleted or enriched patterns occur. The REE patterns of the metabasalts from three of these sequences, i.e. the Lykling, Solund and Stavfjorden ophiolite fragments show little within-sequence but large between-sequence variation. The REE patterns of the metabasalts from the Gullfjellet (Major Bergen Arc) and Skålvær ophiolite fragments, however, show significant within-sequence variations, indicative of local source heterogeneties.When incompatible trace elements such as Ta, Nb, Ce, P, Zr, Hf, Sm, Ti, Y and Yb are normalized against average MORB, the metabasalts can be subdivided into two major groups. One group, geographically comprising the ophiolite fragments north of Bergen (i.e. Solund, Stavfjorden og Skålvær) show trace element ratios similar to average MORB, whereas the other group, defined by the Gullfjellet and Lykling ophiolite fragments (from Bergen southwards) differ significantly with respect to Yb/Y, Ti/Y and Nb/Ce ratios. These features are discussed in terms of trace element patterns in basalts from oceanic islands, island arcs and back-arc basins, and it is tentatively concluded that they reflect partial melts from a mid-oceanic mantle, or probably a back-arc basin mantle, which differed chemically from that of the northwestern Norwegian ophiolite fragments.  相似文献   
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