二相随机介质有效电导率的广义混合率模型研究(英文)

广义混合率模型目前多应用于岩石的流变、杨氏模量等力学性质的研究,较少应用于多相介质岩石的有效电导率研究。本文利用三维有限元方法计算得到大量二相随机介质模型的有效电导率数据,引入广义混合率的有效电导率模型进行数据拟合,发现广义混合率模型参数J与两相介质电导率比值有关,并首次获得参数 J 与两相介质电导率比值之间的关系式,据此可以快速准确的预测(计算)任意二相介质的有效电导率,其结果较已有的随机介质模型和有效介质理论模型公式更为准确,为精细储集层评价奠定坚实基础。     

Evolution of east coast of India — A plate tectonic reconstruction

The evolution of east coast of India sis discussed within the ambit of clearly identifiable four major tectonic stages which had a profound effect in shaping the tectonic grain of the east coast basins. The evolutionary process began with rift related crustal extension between India and Sri Lanka as a consequence of Africa-Antarctica rifting and development of Natal Basin. An arm of this rift led to initial extension in the Cauvery Basin and failed. Later, the India-West Australia rift propagated further in southwesterly direction initiating Mahanadi and Krishna-Godavari Basins. This extension was an oblique one with Nayudupeta high acting as pivot. The oblique extension followed by asymmetric seafloor spreading developed transpression along India-Sri Lanka and Antarctica junction, resulting in a NNW-SSE trending transcurrent fault along which Antarctica moved southward. Subsequently, entire east coast evolved through a more or less uniform post rift stage.     

Annual gametogenesis and reproductive effort of the limpet <Emphasis Type="Italic">Cellana grata</Emphasis> (Gould, 1859) (Gastropoda: Nacellidae) in a rocky intertidal beach at Ulleungdo Island off the east coast of Korea

Widely distributed from the northern coast of Vietnam to the northern Japan, the limpet Cellana grata (Gould, 1859) occurs commonly on the south and east coasts of Korea. Despite their wide distribution range, few studies have investigated the annual gametogenesis and reproductive effort of C. grata. In an attempt to understand the reproductive physiology of the limpet, we investigated the annual gametogenesis and reproductive effort of C. grata from Ulleungdo Island off the east coast of Korea. Histology revealed that the gonial mitosis commenced in January, as the female exhibited small oogonia (10–40 μm) in the follicle. From March to June, the oocyte size increased dramatically, and fully mature eggs (110–170 μm in diameter) appeared in early summer. First spawning males and females were observed in July, as the surface seawater temperature (SST) reached 22.1°C. The spawning male and females could be observed until the end of December. Gonad somatic index (GSI), a ratio of gonad mass to the total tissue weight, of the male ranged from 0.6 (April) to 17.9 (July), while the female GSI varied from 1.0 (February) to 18.3 (July). GSI of male and female declined rapidly from July to August, suggesting that the major purse of the spawning at the study site was between July and August. Our study suggested that the commercial catch of C. grata during July and August must be suspended at Ulleungdo Island, in order to protect the spawning limpets, which enhances C. grata recruitment and the population.     

Analysis of the Seasonal Variation of CO<Subscript>2</Subscript> Concentration in China Based on GOSAT Satellite Data

Carbon dioxide (CO₂) is one of the major gases that contribute to the global warming. Therefore, studying the distribution of CO₂ can help people understand the carbon cycle. Based on the GOSAT retrieved CO₂ products, the temporal and spatial distribution and seasonal variation of CO₂ concentration were analyzed from 2011 to 2015. CO₂ concentration has obvious seasonal variation. It was low in summer, and was high in spring, and the annual increase was about 2 ppm. Nevertheless, the annual growth rate of CO₂ concentration in summer was higher than that in spring, it was 0.5425% in summer and was 0.46% in spring. CO₂ concentration was low in the northwest and was high in the southeast. The growth rate of CO₂ was 2.8 ppm in the northwest and was 3.42 ppm in the southeast. More human’s activities made CO₂ concentration higher in the southeast than that in other regions.     

Investigation of waste disposal areas using electrical methods: a case study from Chania,Crete, Greece

A geophysical investigation of a landfill area was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical resistivity tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modeling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7 km east of Chania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36 m. The resulted images conduced, to overcome geotechnical problems since the spatial distribution of karstic voids was determined, to plan the future sites for waste disposal as the geological conditions were studied in detail and to reliably estimate the thickness of the already deposited wastes. The resulted images were confirmed using available borehole logs and ambient noise measurements.     

Hydraulic Conductivity Tests for Evaluating Compatibility of Lateritic Soil—Fly Ash Mixtures with Municipal Waste Leachate

Long term competent performance of liner systems is a critical issue in the design and construction of waste repositories due to adverse interactions associated with leachate generated by wastes. This study was conducted to verify the efficacy of fly ash stabilization in enhancing compatibility between lateritic soil and municipal waste leachate. Applications investigated include soil mixtures containing 0, 5, 10, 15, and 20% fly ash compacted at approximately 2% wet of optimum moisture content with modified proctor energy. Baseline hydraulic conductivity was first established at every level of fly ash content by permeating soil mixtures with tap water before permeation with leachate in a compaction mould permeameter using the falling head test method. Results show that the trend in hydraulic conductivity of specimen containing 0% fly ash was characterized by a gradual but erratic decrease which may suggests partial entry of the leachate cations into the double layer. Conversely, specimens containing fly ash showed a general trend consisting of an initial drop in k (up to an order of magnitude) that was followed by slight decrease sustained until k stabilized and later terminated. Above 10% fly ash content, the relatively high values of k observed was not connected with the reactivity of the soil mixtures with leachate, rather it may be attributed to excessive fly ash content that altered their textural and hydraulic properties. The result of this study is potentially significant in the assessment of fly ash as a compatibility enhancing agent which can be admixed in barrier materials that are susceptible to adverse reactions with the liquid to be contained.     

The spatial implications of the functional proximity deriving from air passenger flows between European metropolitan urban regions

Until recently the traditional spatial configuration of the European geography was based upon the core-periphery model. The ‘pentagon’, broadly defined as lying between London, Paris, Milan, Munich and Hamburg, was seen as the core area characterised by having the highest concentration of economic development in the European Union (EU), with the remainder of the European territory viewed as peripheral, albeit to varying degrees. In a number of cases such peripheral areas equated with clear regional disparities. The elaboration of the European Spatial Development Perspective (ESDP) (CEC, European spatial development perspective, towards balanced and sustainable development in the territory of the European Union, 1999) challenged this core-periphery model. European spatial planning policies, aimed at encouraging social and economic, and with ever increasing importance, territorial cohesion, seek amongst other aspects to encourage the development of a balanced and polycentric urban system. This paper adopts a network analysis approach to the analysis of air passenger flows between some 28 principal European metropolitan urban regions. The evaluation of these flows contributes to an enhanced comprehension of the spatial dynamics of the European metropolitan territory which goes beyond that deriving from the more standard analyses of the individual components of the urban system. Several indicators are used, deriving from gravitational modelling techniques, to analyse the complexity of the air passenger flows. A multidimensional scaling (MDS) technique is introduced in order to interpret and visualise the resulting spatial configuration and positioning of the different metropolitan centres within the conceptual European ‘space of air passenger flows’, thereby contrasting with the more traditional map-based geographical image of Europe, based upon Cartesian coordinates.

Application of bacteria-plant association in biodegradation of diesel oil pollutants in soil

The bacteria and plants were associated to remove diesel oil pollutants from soil.Three efficiently degrading bacteria(named strains Q10,Q14 and Q18,respectively) were isolated.Two plants(alfalfa and Indian mustard) were selected to form the association.Biodegradation of diesel oil pollutants in soil was accelerated by bacteria-plants association.The main results are summarized as follows.The plants-bacteria association was more effective in biodegradation of diesel oil pollutants in soil than in respective experiments carried out with plants or bacteria alone.Strain Q18-Indian mustard association resulted in the maximum diesel oil reduction(69.18%).The activities of catalase and polyphenol oxidase in soil were enhanced and microbial populations in soil,especially in rhizosphere,were also stimulated in the treatment of bacteria-plant association.Overall,the soil conditions might be improved by alfalfa or Indian mustard to benefit the growth of bacteria,which resulted in degradation of diesel oil pollutants more effective by the bacteria-plant association.The bacteria-plants association may be a better approach to the removal of diesel oil pollutants from soil.     

Separate lead isotope analyses of leachate and residue rock fractions: implications for metal source tracing in ore deposit studies

Separate lead isotope analyses of leachate and residue fractions are applied to a broad spectrum of rocks commonly investigated in metallogenic studies. Resulting data highlight a systematic behavior of leachate and residue fractions with respect to lead isotope compositions, which essentially depends on the mineralogical composition of the rock. Granitoid and high-grade metamorphic rocks have residue compositions virtually identical to common lead. In contrast, low-grade metasedimentary rocks may have residue compositions swamped by radiogenic lead of leach-resistant zircons. Mafic magmatic rocks have residues that are often more radiogenic than leachates, depending on the ratio of leach-refractory zircons to common lead in the residual fraction of these rocks. Separate leachate and residue analyses of source rocks provide two lead isotope end members whose mixture may represent lead with the appropriate ore fluid composition. Our leaching experiments indicate that hot acid solutions (and by inference hydrothermal fluids) preferentially leach radiogenic lead from medium- to high-grade metamorphic and granitoid rocks, whereas they preferentially leach common lead from low-grade metasedimentary and mafic magmatic rocks. The method presented in this study provides a reliable alternative to other methods (i.e., age-correction of bulk-rock compositions) for the determination of the common lead signature of felsic to intermediate magmatic rocks. This may be preferable to age-corrected bulk-rock analyses, where ages to apply for corrections of bulk-rock data are not known or where moderately to highly altered rocks must be used. Case studies of orogenic gold and MVT districts of Peru (Pataz and San Vicente, respectively) show that separate leachate and residue lead isotope analyses carried out systematically on whole rocks allow a more thorough evaluation of metal source reservoirs than does the standard method of age-corrected or uncorrected bulk-rock analyses.     

Field and Laboratory Tests Investigating Settlements of Foundations on Weathered Keuper Marl

Measured settlements of buildings on the weathered Keuper Marl appeared to be much smaller than calculated settlements, which were based on stiffness modulus from standard oedometer tests. Therefore, both special triaxial K ₀-tests and oedometer tests were carried out for an accurate determination of stiffness moduli. Modulus obtained in the triaxial K ₀-tests were at least two to three times the values obtained in the oedometer tests. To verify observations from the laboratory tests, the loads and the settlements of two single footings on weathered Keuper mudstone have been measured during construction of a building over 1 year. Also, a large scale footing load test with measurements of deformations were conducted on the weathered Keuper mudstone. The measured settlements of the two single footings and the tested foundation were compared with the settlements based on conventional calculations with moduli from oedometer tests and triaxial K ₀-tests. Up to a foundation pressure of σ_v = 500 kN/m2 the calculated settlement based on E _S-modulus obtained from triaxial K ₀-tests was found to correspond well to the measured deformation. For foundation pressure beyond 500 kN/m2, the foundation response was highly non-linear and it could not be described any more with the linear-elastic model. Therefore the footing load test was also simulated by FEM analyses.