首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11篇
  免费   1篇
  2018年   3篇
  2017年   1篇
  2016年   4篇
  2015年   2篇
  2014年   1篇
  2008年   1篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
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   
2.
In recent decades in Europe, municipalities have promoted many poorly qualified and widespread industrial parks. These policies have caused various problems such as oversupply of industrial land, obsolescence and high vacancy rates. The future of these sites is uncertain and has become a key issue in planning. Nowadays, policies are focused on upgrading these sites and on implementing regional coordinated practices. This paper describes a methodological approach to identifying a subregional network of industrial parks in the Ave valley, Portugal. The network is based on the parks’ attractiveness and has the purpose of supporting planning policies in terms of upgrading and providing new sites. The approach was based on a multi-criteria analysis whereby the parks were ranked according to their attractiveness considering their coverage in terms of infrastructures, services and accessibility. Results show that the majority of the existing and planned parks, even if upgraded, will not be very attractive and will be limited to a municipal scale due to structural problems related to their location and poor coverage. Moreover, the paper also discusses the challenges in implementing this planning approach at a subregional level. Despite the specificities of the case study, this methodology could be adopted in similar studies.  相似文献   
3.
We apply GIS techniques to analyze a carefully selected database of 93 Early Neolithic sites in the Iberian Peninsula. This allows us to study the spatial dynamics of the Neolithic transition in Iberia. We study how the Neolithic was introduced into the peninsula in order to test the hypothesis that the Neolithic was introduced almost simultaneously from two sources: one at the northeast (via the Mediterranean coast) and another one at the south (possibly from Northern Africa). We also analyze how the expansion of the Neolithic transition took place within the Iberian Peninsula and measure local rates of spread in order to identify regions with fast and slow rates (such as the slowdown at the Cantabrian coast). In addition, we attempt to reproduce the main results obtained from the GIS analysis by applying reaction–dispersal models to the expansion of the Neolithic transition in the Iberian Peninsula. We conclude that a model with two sources is a reasonable assumption that agrees better with the archaeological data available at present than a model with a single source.  相似文献   
4.
This article discusses the legacy of Amílcar Cabral. The main question it deals with is how to read Cabral today when the system that prompted the emergence of his theory, colonialism, is no longer there. The main argument of this article is, therefore, that a disjuncture exists in the ways Cabral is discussed today. Cabral was certainly a great nationalist and revolutionary, and his contribution crucial for the ways in which revolution in Africa has been apprehended. However, his theoretical contribution should be ascertained alongside the analyses of the realities his emancipatory project addressed. Basically, this article suggests a reading of Cabral's theory in the context of the practices and context his theory was addressing. For doing this, this article examines the main tenets of Cabral's theory, on nationalism, alongside the responses the Portuguese had come up with under the rubric of counter-insurgency strategies. The contribution this article tries to put forward is that critical purchase in reading Cabral today has to take into account the complexities of the anticolonial past that brought us to our postcolonial present.  相似文献   
5.
The most serious form of degradation of historical azulejos is the spall of the glaze and it is widely accepted that the crystallization of salts dissolved in water circulating in the masonry is its main cause. This article reports the results of an accelerated aging test aimed at studying the physical deterioration of azulejos caused by cycles of dissolution and re-crystallization of sodium chloride (NaCl). Experiments were carried out on 26 Portuguese azulejos from the 17th–19th century, some of which with original manufacturing defects or with varying degrees of previous decay.

The results of 75 cycles over 18 months did not verify that the action of NaCl could trigger an accelerated loss of glaze in a healthy azulejo. Furthermore, the results lead to the induction that there must be other, eventually concurring, causes for the spall of glaze than a simple challenge with salts that crystallize by evaporation.  相似文献   

6.
7.
What factors account for local government land use practices and their choices among specific growth management policy instruments? We apply the political market framework to examine how land use policy choices in Florida are shaped by institutional features of county governments and the demands of organizations and interests in a community. Local policy decisions reflect a balance of the conflicting interests and responses to economic and political pressures. The results demonstrate that county government structure and election rules play critical roles in the adoption of urban service boundaries, incentive zoning, and transfer of development rights programs. We report evidence consistent with the argument that these “second‐generation” growth management policies are motivated by exclusionary goals.  相似文献   
8.
It is stated that 3D recording and modeling of heritage buildings entail accurate building models (as-built). However, this paper presents an analysis of the 3D modeling accuracy for the creation of historical building information models (HBIM), considering the complexity and the deformations of historical buildings, using point cloud data and BIM tools. The 3D modeling processes analyzed are based on a three-stage semi-automatic approach leading to the generation of HBIM, including manual and automatic processes. The three stages consist of: (a) optical and terrestrial laser scanning; (b) meshing processes; and finally (c) 3D solid modeling to be assembled into HBIM. Next, this approach analyzed the mesh deformations generated automatically in comparison to the initial point cloud data. The deformations and the accuracy evaluation have been undertaken using different commercial software. Finally, our modeling approach shows that it can improve the accuracy of the 3D models achieved using existing BIM technologies.  相似文献   
9.
Do local policymakers strategically use delay in permitting development to forestall the growth machine? The mantras of smart growth and sustainable development assume local governments can balance the competing values of economic development, ecology, and equity interests in a community. We employ a political market framework to explain differences in local government land use decisions. This framework conceptualizes policy choices as resulting from the interplay between the aggregate policy demand by residents, developers, and environmental interests and the aggregate supply by government authorities. Delays can be imposed strategically through processes of development approval by city governments where industry strength and form of government vary within county‐level service‐delivery fragmentation. We utilize novel Bayesian multilevel modelling of data collected from 2007 and 2015 surveys of Florida city planners and find strong institutional effects and multilevel relationships.  相似文献   
10.
In this study, Monte Carlo (MC) simulations combined with energy dispersive X-ray fluorescence (EDXRF) spectroscopy have been used to characterize non-destructively a collection of Cu-based artifacts recovered from two archeological sites in southern Portugal: (a) the Chalcolithic E.T.A.R. site of Vila Nova de Mil Fontes and (b) the Middle Bronze Age site of Quinta do Estácio 6. The metal artifacts show a multilayered structure made up of three distinct layers: (a) brownish carbonate soil-derived crust, (b) green oxidized corrosion patina, and (c) bulk metal. In order to assess the reliability of the EDXRF-based Monte Carlo simulations to reproduce the composition of the alloy substrate in archeological bronze artifacts without the need to previously remove the superficial corrosion and soil derived patinas, EDXRF analysis together with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was also performed on cleaned and patina-/crust-coated areas of the artifacts. Characterization of the mineralogical composition of the corrosion products in the surface patinas was further determined by means of X-ray diffraction (XRD). Results suggest that the adopted EDXRF/Monte Carlo protocol may represent a safe and fast analytical approach in the quantitative characterization of the bulk chemical composition of Cu-based metal artifacts even in the presence of fairly thick corrosion patinas and/or soil-derived encrustations at the surface of the archeological objects.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号