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The vault of Villaviciosa is one of the oldest existing examples of a true ribbed vault, and is the first of the crossed-arch type. Although its perfection suggests earlier trials, none has been found so far. It predates the oldest Romanesque ribbed vaults by more than a century. Notwithstanding its importance, no construction and structural study has ever been done; neither has an accurate survey been published. The purpose of this article is to fill this gap in the history of vault construction. A detailed survey has been made, providing the first accurate drawings of the vault. A close inspection of the extrados, completed with a visual inspection of interior damages, has allowed ascertaining the main construction features. With the geometry and the material data a structural analysis has been carried out. This analysis explains the fundamental structural behavior of the vault and throws new light into some historical issues; for example, it leads to discarding the widespread belief that the ribs are decorative: they are supporting the weight of the vault. 相似文献
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The debate about the complex issues of human development during the Middle to Upper Palaeolithic transition period (45–35 ka BP) has been hampered by concerns about the reliability of the radiocarbon dating method. Large 14C anomalies were postulated and radiocarbon dating was considered flawed. We show here that these issues are no longer relevant, because the large anomalies are artefacts beyond plausible physical limits for their magnitude. Previous inconsistencies between 14C radiocarbon datasets have been resolved, and a new radiocarbon calibration curve, IntCal09 (Reimer et al., 2009), was created. Improved procedures for bone collagen extraction and charcoal pre-treatment generally result in older ages, consistent with independently dated time markers. 相似文献
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The emotional geography of a mine closure: a study of the Ravensthorpe nickel mine in Western Australia 总被引:1,自引:0,他引:1
This paper engages with the literature on emotional geographies to report on a case study of the emotions surrounding the closure of a nickel mine in the shire of Ravensthorpe in the south-west of Western Australia in January 2009. Two themes from the affect-infused narratives of pre- and post-mine community members are outlined. The first, which challenges constructions of the closure as a purely industrial and economic concern, focuses on the intense feelings the shut-down invoked amongst participants. The second theme explores the way in which the owner of the mine, BHP Billiton, worked to suppress and regulate affective reactions to the closure and thus reveals the highly political nature of emotions. 相似文献
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The Evolution of Administrative Systems in Kuwait,Saudi Arabia,and Qatar: The Challenge of Implementing Market Based Reforms 下载免费PDF全文
Mhamed Biygautane MA Paula Gerber PhD Graeme Hodge PhD 《Domes : digest of Middle East studies》2017,26(1):97-126
The dramatic plunge in oil prices since the second half of 2014 poses serious challenges for the oil dependent states of Kuwait, Saudi Arabia, and Qatar, and revives their interest in accelerating the implementation of market‐based reforms such as outsourcing, privatization, and public–private partnerships. This article challenges the assumption that these reforms offer a panacea for administrative change, and argues that while they might appear to be a solution to the growing fiscal constraints in the three Gulf states, considerable administrative, cultural, economic, and political barriers hinder their effective implementation. The conclusion reached is that western labels of market‐based reforms offer limited options for the three states in the absence of strong political will to make fundamental reforms that could alter the state–society relations. It is suggested that further theorization of administrative change is required in cultural contexts, such as the Gulf region, where administration and society are intertwined, and where trying to minimize the role and size of the state, poses a direct threat to the political legitimacy of the ruling elites. 相似文献
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João Pedro dos Santos Laranjeira Helena Cruz Ana Paula Ferreira Pinto Carlos Pina dos Santos Joana Filipa Pereira 《International Journal of Architectural Heritage》2015,9(7):866-882
Fire safety is an important issue of building safety, especially when the building’s fire load contents enhance the risks of fire deflagration. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardants. This study focuses on the surface protection of existing timber roof structures against fire, through the use of fire retardant (FR) treatments applied on site. An experimental investigation was carried out to study the effect of FR treatments on timber reaction to fire, with a special emphasis on timber members with biological deterioration and previously treated with preservative products. The behaviour and effectiveness of intumescent and non-intumescent treatments was also investigated. The study showed that the application of FR treatments improved the reaction to fire of timber, even in the presence of previous preservative treatments. However, the choice of the specific FR treatment should take into account the substrate conditions. In addition, test results suggest that protection systems involving multi layers (intumescent and non-intumescent) with different functioning modes each are likely to have a good global performance on the protection of timber elements against fire. 相似文献
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Vibeke Vandrup Martens Ove Bergersen Michel Vorenhout Paula Utigard Sandvik Jørgen Hollesen 《Conservation and Management of Archaeological Sites》2013,15(1-3):8-29
This paper presents archaeological observations and results of palaeoecological and geo-chemical analyses of archaeological deposits from two rural sites in northernmost Norway. These are combined with climate data and the first period of continuous monitoring of soil temperature, moisture, and redox potential in sections. This data constitutes the basic research material for evaluations of conservation state and preservation conditions. The data has been collected in collaboration with the partners of a cross-disciplinary project: ‘Archaeological Deposits in a Changing Climate. In situ Preservation of Farm Mounds in Northern Norway’ funded by the Norwegian Council for Research (http://www.niku.no/en/archaeology/environmental_monitoring/archaeological_deposits_in_a_changing_climate_in_situ_preservation_of_farm_mounds/). This is an important Norwegian research initiative on monitoring of rural archaeological deposits, and the results have consequences for heritage management of a large number of sites from all periods. Palaeoecological analyses and redox measurements have revealed ongoing decay that might not otherwise have been detected. Decay studies indicate that both site types may be at risk with the predicted climate change. Some mitigating acts are suggested. 相似文献
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