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991.
This study reconstructs the palaeohydrogeologic evolution of the shallow‐to‐moderate Mesozoic subsidence history for the Mecsekalja Zone (MZ), a narrow metamorphic belt in the eastern Mecsek Mountains, Hungary. Brittle deformation of the MZ produced a vein system with a cement history consisting of five sequential carbonate generations and one quartz phase. Vein textures suggest different fluid‐flow mechanisms for the parent fluids of subsequent cement generations. Combined microthermometric and stable‐isotope measurements permit reconstruction of the character of subsequent fluid generations with different flow types, as defined by vein textures, yielding new information regarding the hydraulic behaviour of a metamorphic crystalline complex. Textural observations and geochemical data suggest that fracture‐controlled flow pathways and externally derived fluids were typical of some flow events, while percolation through the rock matrix and the relationship to the Cretaceous volcanism and dyke emplacement were typical of others. The difference in the mode of calcite deposition from pervasive fluids (i.e. pervasive carbonatisation along grain boundaries versus deposition in antitaxial veins) between two calcite generations related to the volcanism inspired a stress‐dependent model of antitaxial vein growth. Textural and isotope variations in a vein generation produced by the same parent fluid indicate rock‐dependent hydraulic behaviour for different rock types, distinct action of the contemporaneous fracture systems and different extents of fluid–rock interaction. Cathodoluminescence microscopy and fluid‐inclusion microthermometry shed light on the possible role of hydraulic fracturing in the formation of massive calcite. The time of formation was estimated from the isotope composition of the oldest calcite generation and its presumptive relationship with the sedimentary sequences to the north, whereas microthermometry permitted conciliation of the reconstructed flow sequence with the Mesozoic subsidence history of the Mórágy Block (including the MZ). 相似文献
992.
The objective of this study is to obtain quantitative evidence of pore‐scale immiscible fluid distribution in oil‐wet and water‐wet porous media using X‐ray computed microtomography. Temporal and spatial saturation profiles, as well as surface and interfacial areas, are thoroughly analyzed through cycles of drainage and imbibition using samples with different wetting characteristics but similar pore structures. The population of individual immiscible fluid structures (‘blobs’) was also evaluated. The specific nonwetting phase surface areas of both porous media are found to be in close correlation with the specific solid surface area. On the other hand, the differing wetting strengths of the two porous media affect the curvature of the fluid–fluid interface and thus the specific meniscus interfacial area of the two porous media. Although the magnitude of the specific meniscus interfacial areas is different, they both trend toward a maximum at wetting phase saturations of 0.35–0.55. The differences in wetting characteristics are also apparent in the blob populations. The number of blobs in the oil‐wet porous media is three times greater than that of the water‐wet porous media at similar saturations; the increase in population is a result of the increase in the amount of smaller blobs inhabiting the smaller pore spaces. The surface areas of individual blobs as a function of the individual blob volumes are found to closely agree with the specific surface area of a sphere at blob volumes below the minimum individual grain volume and with the specific pore space surface area above this volume. These results show how wettability and saturation history influence the distribution of immiscible fluids within the pore space. 相似文献
993.
P. CHAMBERLAIN R. DREWELLO L. KORN W. BAUER T. GOUGH A. AL‐FOUZAN M. COLLINS N. VAN DOORN O. CRAIG C. HERON 《Archaeometry》2011,53(4):830-841
As part of an ongoing project at the World Heritage Site of Bukhara, we investigated the glue used in the construction of the Khoja Zaynuddin mosque. Analysis by a range of techniques confirmed that it consisted of a collagen‐based glue. However, the glue contained many non‐protein constituents. The presence of lipid material suggests that the glue was produced by a relatively unsophisticated process. More surprisingly, various marker compounds of urine were found. Study of the viscosity of a mixture of a modern collagen‐based glue and urea showed that the presence of urea at a concentration typical of human urine reduced the viscosity of the glue, thus improving its spreading characteristics and enabling its use at a lower temperature. Whilst the advantages of adding urea to glue were known to craftsmen in Europe and America in the 19th century, it would appear that the builders of Bukhara were aware of the technique, using less pure components, at a significantly earlier date. 相似文献
994.
A. DOMÉNECH‐CARBÓ M. T. DOMÉNECH‐CARBÓ M. A. PEIRÓ‐RONDA L. OSETE‐CORTINA 《Archaeometry》2011,53(6):1193-1211
An essentially non‐invasive electrochemical methodology addressed to the authentication of archaeological lead is described. The method is based on the record of the voltammetric response of nanosamples from the archaeological artefact mechanically transferred to a graphite ‘pencil’ electrode in contact with aqueous buffers. Three diagnostic criteria for authentication are described based on the appearance of: (i) oxidative dissolution signals for trace metals like copper, arsenic, antimony and, often, tin and silver accompanying stripping peaks for lead, (ii) peak potential shifts for reduction peaks for patination products, and (iii) the presence of reduction peaks for PbO2. The method is applied to the authentication of an Iberian lead plate from the Tossal de Sant Miquel (Llíria, Spain) site using a series of genuine and false pieces from different provenances in the Valencian region (Spain). 相似文献
995.
996.
997.
Elizabeth R. Alexandrin 《Iranian studies》2011,44(1):99-115
As a key primary source for the history of the eleventh-century Isma‘ili majlis, the Fatimid chief missionary al-Mu'ayyad fi al-Din al-Shirazi's autobiographical Sira offers a prime opportunity to consider the application of centralizing features of the Fatimid state in eleventh-century Buyid Shiraz. Previous studies on the Fatimid majlis have raised questions about an Isma‘ili core curriculum as well as the intended audience/s of Fatimid da‘wa teachings. This article situates al-Mu'ayyad's memoir in the broader context of the Persian and Arabic historiographical traditions in order to provide new insights into the transmission of Isma‘ili doctrines in different social settings outside of Fatimid Cairo. It concludes that Abu Kalijar's study sessions with al-Mu'ayyad suggest that Qadi al-Nu‘man's Kitab Da‘a'im al-Islam was used as a core text for introducing some of the main principles of Fatimid religio-political rule in addition to Isma‘ili doctrines to non-Isma‘ili audiences. 相似文献
998.
999.
Joseph T. Ripberger 《政策研究杂志》2011,39(2):239-259
While scholars have made great strides in formulating theories and measuring public attention, “most important problem” and media‐based indicators are less than ideal measures. In order to address this shortcoming, this article borrows from health‐care epidemiology to measure public attention based on Internet search trends. In doing so, it reviews the innovative ways in which scientists have used search activity to track the spread of infectious disease, discusses the ease and flexibility with which search data can be gathered, and then subjects a Google‐based search measure to a series of validity tests. In particular, the analysis subjects the proposed measure to a battery of visual and statistical tests for convergent validity by comparing it with the most commonly used media‐based measure of public attention—issue coverage in the New York Times. Across a range of policy issues (health care, global warming, and terrorism), the proposed measure demonstrates convergent validity. The article concludes by posing a series of important questions that the new measure will allow researchers to address. 相似文献
1000.
Assessing the impact of prehistoric sites on their local environment is difficult to accomplish with standard archaeological methods. Simulation modeling offers a solution to this issue, but it is first necessary to delimit a site catchment, or “zone of impact”, around archaeological sites in which to carry out human–environment interaction modeling. To that end, I have developed a new method for GIS-based catchment reconstruction and distilled it into a custom module (r.catchment) for GRASS GIS, which calculates catchments of a given area based on anisotropic travel costs from a point of origin. One method of applying this new module in exploratory catchment modeling is discussed using the pastoral economy of the Late Neolithic period in Wadi Ziqlâb, Northern Jordan as a test case. A model of Late Neolithic herding economy and ecology is constructed, which combines data from archaeology, phytogeography, range science, agronomy, and ethnohistory. Four sizes of pastoral catchments are then derived using r.catchment, and the herd ecology model is used to estimate the stocking-rate (carrying capacity) of mixed goat and sheep herds for each catchment. The human populations these herd numbers could support (between 3 and 630 people in the Wadi) are then compared with human population estimates derived from household architectural analyses (between 18 and 54 people in the Wadi) to determine the most probable catchment configurations. The results indicate that the most probable zone of impact around the known Late Neolithic sites in Wadi Ziqlâb was somewhere between 9 and 20 square kilometers, delineated by 3 and 4.5 km pasture radii respectively. 相似文献