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71.
This article aims at presenting and discussing the strategies for updating the finite element numerical modeling of stone masonry arch bridges using operational modal analysis. The study comprehended three bridges: two old ones, the St. Lázaro and the Lagoncinha bridges, and a recently constructed bridge in Vila Fria, Portugal. Updating of the bridge models is performed by comparing the numerical and experimental modal parameters. Three-dimensional detailed numerical models are used to perform modal analysis of the bridges. Experimental modal identification of the bridges is based on the measurement of their acceleration responses during normal operation. The assigned material properties are also based on available results obtained from in situ and laboratory tests and on the results of visual inspection and historical research carried out for both old bridges.  相似文献   
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武友德 《人文地理》2000,15(3):69-72
西部不发达区域是我国自然资源密集地区,极具开发潜力,其经济成长采取自然资源转换模式具有客观必然性。但是传统的自然资源要素转换模式已严重制约着西部地区经济的持续发展。本通过对西部地区自然资源优势、资源开发中的技术结构和利益分配机制以及资源转换模式等问题的系统思考,提出了提升区域自然资源转换模式的构想。  相似文献   
73.
Are there traditions of folk ritual practice in Australian historical contexts, and are they observable in the archaeological record? Studies from the US and UK have documented a range of practices suggesting the persistence of British and European traditions of folk magic well into the twentieth century and previous historical work has identified numerous examples of ritual concealments in Australian buildings. In examining over 4,500 Australian historical archaeological sources, however, we found very few examples of possible folk ritual practices. This raises the question of why such practices are not being captured by current archaeological recording methods. As counterpoint, a general model is constructed from US, UK and Australian work that raises intriguing possibilities for the situating of superstitious behavior in Australian historical archaeology, including the contexts in which people might be more prone to practise such behaviors and how they might be materially identifiable.  相似文献   
74.
The aim of the paper is to summarise the present state of knowledge concerning bitumen trade in the Near East from the Palaeolithic (70,000 BP) to the Early Islamic period. During the Palaeolithic and Early Neolithic period, bitumen utilisation was mostly concentrated in settlements close to oil seeps. From the Ubaid 3 period, bitumen from the Mosul area became more important and was traded as far as the southern Persian Gulf. The Uruk period is a turning point for Mesopotamian history as settlements evolved into city‐states. These cities had a great need for raw materials, and this marks the beginning of large‐scale exploitation of Hit bitumen. This bitumen was traded at settlements along the Euphrates, where a large trade network was established. Hit bitumen entered the Persian Gulf at the turn of the second millennium (Dilmun period). Bitumen from Iraq (Mosul and Hit) became predominantly used in most settlements along the southern coast of the Gulf. During this period Iranian bitumen was also exported and this supply tended to increase, especially during the Partho‐Sasanian period. Dead Sea bitumen had its own exchange network, which was concentrated across present‐day Israel and Egypt where it was extensively used for mummification.  相似文献   
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The rock art in Altamira Cave was the first ensemble of Palaeolithic parietal art to be identified scientifically (Sautuola, 1880). Due to the great thematic, technical and stylistic variety of the art in the cave, which constitutes one of the most complete Palaeolithic art ensembles, Altamira was listed as World Heritage by UNESCO in 1985. Uranium-series dating has recently been applied to figures on the decorated ceiling in the cave. Several motifs are partly covered by thin layers of calcite precipitates, whose formation process is datable by this method. The results provide the date when the calcite formed, which gives a minimum age for the underlying depictions. These results confirm that the parietal art at Altamira was produced during a prolonged period of time, at least 20,000 years (between 35,000 and 15,200 years ago), and that part of the ensemble corresponds to the Aurignacian period.  相似文献   
77.
ABSTRACT

Giovanni Freppa (1795–1870), a well-known antiquarian, was instrumental in propelling the Ginori maiolica firm to reinvent the technique of Renaissance lustreware. The so-called ‘Freppa Scandal’ resulted after he sold as authentic Renaissance pieces a number of plates made by Ginori. Freppa was also famous, or rather infamous, for his exploitation of the young sculptor Giovanni Bastianini, whose remarkable neo-Renaissance portrait busts were sometimes sold as authentic Renaissance works. The Louvre purchased for an enormous price a bust believed to be a Renaissance masterpiece; but it was actually executed by Bastianini in 1864 on commission from Freppa, resulting in ‘the Benivieni Affair’. But this article is not primarily intended to expand on Freppa’s transactions in the art world; rather, it highlights his activities in many other spheres, including a failed publishing project with Giacomo Leopardi, among other activities. Freppa was a more complex individual than indicated merely by the two above-mentioned scandals.  相似文献   
78.
There is an increasing awareness of the potentials of nonlinear modeling in regional science. This can be explained partly by the recognition of the limitations of conventional equilibrium models in complex situations, and also by the easy availability and accessibility of sophisticated computational techniques. Among the class of nonlinear models, dynamic variants based on, for example, chaos theory stand out as an interesting approach. However, the operational significance of such approaches is still rather limited and a rigorous statistical-econometric treatment of nonlinear dynamic modeling experiments is lacking. Against this background this paper is concerned with a methodological and empirical analysis of a general misspecification test for spatial regression models that is expected to have power against nonlinearity, spatial dependence, and heteroskedasticity. The paper seeks to break new research ground by linking the classical diagnostic tools developed in spatial econometrics to a misspecification test derived directly from chaos theory—the BDS test, developed by Brock, Dechert, and Scheinkman (1987). A spatial variant of the BDS test is introduced and applied in the context of two examples of spatial process models, one of which is concerned with the spatial distribution of regional investments in The Netherlands, the other with spatial crime patterns in Columbus, Ohio.  相似文献   
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