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21.
Joaquim Alves Gaspar 《The Cartographic journal》2013,50(4):318-324
In this paper, the results of a cartometric analysis of a number of Portuguese and Spanish charts of the sixteenth and seventeenth centuries are presented and conclusions are drawn concerning the length of the degree of latitude adopted in the Iberian nautical cartography of the Renaissance. Under the light of what we know about the navigational and charting methods of the time, a new interpretation of the textual and cartographic sources is proposed. Rather than being the result of technical considerations or precise measurements, the adoption of the various standards during this long period appears to be no more than the echoes of the traditional models of the Earth and of the political disputes between Portugal and Spain. 相似文献
22.
Chiara Del Ventisette Nicola Casagli Joaquim Fortuny-Guasch Dario Tarchi 《Landslides》2012,9(4):497-509
The active Ruinon rockslide is located on the left bank of the Frodolfo River valley (Valfurva, Italian Alps) and is developed on the Confinale deep-seated gravitational slope deformation. Ruinon landslide is a major hazard for valley inhabitants in that rapid movement might dam the stream and create a debris flow. The landslide is strongly controlled by preexisting structural features and is believed to have been triggered by postglacial debuttressing. Ground-based radar interferometry has been used to map surface deformation over time of the entire unstable zone of Ruinon landslide with high spatial resolution and at a very high temporal acquisition rate (about five images per hour). The activity of the landslide shows strong periodicity, with summer and autumn accelerations and winter deceleration. From a correlation between the landslide acceleration and a class of rainfall event, we deduce the specific rainfall conditions that accelerate the instability of the landslide area. The study results suggest an improved tool for early warning of events of potentially catastrophic landslide instability. 相似文献
23.
Sylvana Melo dos Santos Jaime Joaquim da Silva Pereira Cabral Ivaldo Dario da Silva Pontes Filho 《Natural Hazards》2012,64(1):421-439
The global positioning system (GPS) is widely used for determining the three-dimensional position of points on earth surface. In the last few years, its use has also been increasingly employed for obtaining vertical geometric coordinates, which associated with the orthometrical altitude of the point can be employed in various civil engineering applications, as has been seen in diverse localities throughout the world. The satisfactory performance of this technology for obtaining excellent precision in vertical coordinates demands some conditions, related to the satellites, such as transmission of signals and, principally, in the case of urbanized areas, the presence of obstructions in the proximity of the equipment, which interferes with the quality and quantity of the information collected. GPS is an efficient technique for the detection of small movements, including the monitoring of soil subsidence. The present article describes adequate forms of the use of GPS in such a way as to guarantee good precision of the resulting vertical coordinates, even under unfavorable situations, such as in coastal areas, where the reference networks for monitoring are implanted in only one of the sides of the point?Cobject region, which makes the situation more difficult and requires careful planning so that the use of GPS reaches the desired precision. 相似文献
24.
Jorge Proen?a António Sousa Gago Joaquim Cardoso Vítor Cóias Raquel Paula 《Bulletin of Earthquake Engineering》2012,10(1):113-133
Traditional non-reinforced masonry walls are particularly prone to failure when subjected to out-of-plane loads and displacements
caused by earthquakes. Moreover, singularities such as openings in fa?ades may trigger local collapse, for either in-plane
or out-of plane motion. Bearing in mind all the former limitations, STAP, with the scientific support of ICIST and LNEC, has
been developing a reduced intrusiveness seismic strengthening methodology for traditional masonry structures. The technique
consists in externally applying Glass Fibre Reinforced Polymer (GFRP) composite strips to one or both faces of walls. Connection
between GFRP composite strips and masonry substrate is enhanced through specifically detailed anchorages or confinement connectors.
This technique has been developed and studied through an extensive series of experimental tests, which are briefly reviewed.
This paper focuses more deeply on the latest experimental program, aimed at the characterization of the masonry-GFRP composite
interface behaviour. This testing program comprised 29 masonry specimens, strengthened with externally bonded GFRP composite
strips with anchorages. The testing variables were the number and spacing of anchorages as well as the loading history type:
monotonic or repeated. Results clearly show that the use of anchorages dramatically enhances bond behaviour and that its number
and spacing have a significant effect on deformation capacity and a less pronounced effect on strength. Based on experimental
evidence, this paper also provides a calculation model and ULS safety assessment procedure for out-of-plane strength of reinforced
masonry walls. This calculation model leads to interaction curves on strengthened masonry walls subjected to compression and
out-of-plane flexure. 相似文献
25.
Ana C. Costa Jo?o A. Santos Joaquim G. Pinto 《Theoretical and Applied Climatology》2012,108(1-2):217-234
Precipitation indices are commonly used as climate change indicators. Considering four Climate Variability and Predictability-recommended indices, this study assesses possible changes in their spatial patterns over Portugal under future climatic conditions. Precipitation data from the regional climate model Consortium for Small-Scale Modelling–Climate version of the Local Model (CCLM) ensemble simulations with ECHAM5/MPI-OM1 boundary conditions are used for this purpose. For recent–past, medians and probability density functions of the CCLM-based indices are validated against station-based and gridded observational dataset from ENSEMBLES-based (gridded daily precipitation data provided by the European Climate Assessment & Dataset project) indices. It is demonstrated that the model is able to realistically reproduce not only precipitation but also the corresponding extreme indices. Climate change projections for 2071–2100 (A1B and B1 SRES scenarios) reveal significant decreases in total precipitation, particularly in autumn over northwestern and southern Portugal, though changes exhibit distinct local and seasonal patterns and are typically stronger for A1B than for B1. The increase in winter precipitation over northeastern Portugal in A1B is the most important exception to the overall drying trend. Contributions of extreme precipitation events to total precipitation are also expected to increase, mainly in winter and spring over northeastern Portugal. Strong projected increases in the dry spell lengths in autumn and spring are also noteworthy, giving evidence for an extension of the dry season from summer to spring and autumn. Although no coupling analysis is undertaken, these changes are qualitatively related to modifications in the large-scale circulation over the Euro-Atlantic area, more specifically to shifts in the position of the Azores High and associated changes in the large-scale pressure gradient over the area. 相似文献
26.
Joaquim C.B. Queiroz José R. Sturaro Augusto C.F. Saraiva Paulo M.B. Landim 《Journal of Geochemical Exploration》2009
This paper presents a methodology based on geostatistical theory for quantifying the risks associated with heavy-metal contamination in the harbor area of Santana, Amapá State, Northern Brazil. In this area there were activities related to the commercialization of manganese ore from Serra do Navio. Manganese and arsenic concentrations at unsampled sites were estimated by postprocessing results from stochastic annealing simulations; the simulations were used to test different criteria for optimization, including average, median, and quantiles. For classifying areas as contaminated or uncontaminated, estimated quantiles based on functions of asymmetric loss showed better results than did estimates based on symmetric loss, such as the average or the median. The use of specific loss functions in the decision-making process can reduce the costs of remediation and health maintenance. The highest global health costs were observed for manganese. 相似文献
27.
Rejane Maria Rodrigues de Luna Silvio Jacks dos Anjos Garnés Jaime Joaquim da Silva Pereira Cabral Sylvana Melo dos Santos 《Natural Hazards》2017,85(3):1363-1392
Facing natural disasters is a priority challenge for cities, exacerbated by increases in urban population and climate change. Improving the resilience of cities is a critical need for the international community and especially for territories exposed to multiple risks, such as Chile. Although disasters are always tragic, the recovery and reconstruction post-disaster may provide a unique opportunity to prevent future suffering, enhancing the resilience of local communities. This paper presents the analysis of two Chilean reconstruction programmes applied in Mehuin and Dichato, after the earthquake and tsunami of 22 May 1960 and 27 February 2010, respectively. In both cases, reconstruction programmes were supported by the Chilean Government, but using different approaches: one focused on providing housing for people injured in the earthquake, while the other also included urban amenities and services. This article proposes an urban morphology analysis framework; in addition, it presents the assessment of the two case studies before and after a disaster, thus evaluating their resilience. By comparing urban morphology resilience pre- and post-disaster, a discussion about the effectiveness of two reconstruction approaches is presented. Finally, conclusions and recommendations to better integrate resilience into urban planning are proposed, with the aim of opening the discussion about how to make cities more resilient to natural disasters. 相似文献
28.
Viscoelastic dampers (VEDs) are one of the most common passive control devices used in new and retrofit building projects which reduce the structure responses and dissipate seismic energy during an earthquake. Various methods to design this kind of dampers have been proposed based on the desired level of additional damping, eigenvalue assignment, modal strain energy, linear quadratic regulator control theories, and other approaches. In the current engineering practice, the popular method is the one based on the modal strain energy that uses the inter-story lateral stiffness as one of the main variables for damper design. However, depending on the configuration of the structure, in some cases the resulting interstory lateral stiffness can be very large. Consequently, the dampers size would also be large producing much more damping than that effectively necessary, resulting in an increase of the overall cost of the supplemental damping system and causing excessive stress on the structural elements connected to the dampers. In this paper an alternative practical design method for structures with VEDs is proposed. This method uses the inter-story shear forces as one of the main variables to accomplish the damper design compared to what was done in previous studies. Nonlinear time-history analyses were conducted on a 7-story reinforced concrete (RC) structure to check the reliability and effectiveness of the proposed method. Comparisons on the seismic performance between the structure without dampers and that equipped with VEDs were carried out. It is concluded that the proposed method results in a very suitable size of dampers, which are able to improve the performance of the structure at all levels of earthquake ground motions and satisfying the drift requirement prescribed in the codes. 相似文献
29.
Cheila Almeida Rui CoelhoMarco Silva Luís BentesPedro Monteiro Joaquim RibeiroKarim Erzini Jorge M.S. Gonçalves 《Estuarine, Coastal and Shelf Science》2008
The faunal communities of four intertidal habitats namely sand, mud, seagrass (Zostera noltii) and seagrass patches (mixSM) of a temperate coastal lagoon, Ria Formosa (southern Portugal), were sampled. A total of 47 species were taken in 428 bottomless drop sampler samples, with the highest number of species and the more commonly occurring species belonging to the Mollusca phylum. The dominance of these gastropod species underlines the importance of the grazing food chain in these habitats. Bittium reticulatum was the most abundant species, being especially abundant in the seagrass habitat. The most frequent and highest biomass species in the community was Carcinus maenas, a predator that makes use of the available resources and that is adapted to the highly variable intertidal environment. Pomatoschistus microps was the most abundant fish species, with highest densities in the mud habitat, which demonstrates an ability to occupy a low depth area. The seagrass habitat had the highest diversity, abundance and biomass, followed by the mixSM habitat and was different from all the others. Assemblages were highly influenced by the presence of vegetation, providing forage and refuge from predation. A well defined summer group was identified in all habitats. These results highlight the importance of seagrass beds and the idea that their decrease implies the decrease of lagoon production through the impoverishment of the trophic structure of the lagoon. 相似文献
30.
Adnan R. Al-Azri Sergey A. Piontkovski Khalid A. Al-Hashmi Joaquim I. Goes Helga do R. Gomes Patricia M. Glibert 《Estuaries and Coasts》2014,37(2):325-338
Cochlodinium polykrikoides formed large blooms in the coastal waters of Oman from October 2008 through mid-January 2009, and satellite images from Aqua-MODIS and region-wide reports suggest that this bloom was found throughout the Arabian Gulf and Sea of Oman for more than 10 months. The unusual occurrence of this species appears to have supplanted the more regularly occurring bloom species, Noctiluca scintillans, in 2008–2009. For the first 2 weeks of the coastal Omani bloom, C. polykrikoides abundance was near monospecific proportions, with cell densities ranging from 4.6?×?103 to 9?×?106 cells L?1 and very high levels of chlorophyll a (78.0 μg L?1) were also recorded. The regional progression of the bloom likely began with stronger than normal upwelling along the Iranian and northern Omani coasts during the southwest monsoon in late summer, followed by discharge of unusually warm coastal plume water along the coast of Oman with the reversal of monsoonal winds in late October. The occurrence and persistence of high densities of C. polykrikoides in Oman coastal water were also significantly influenced by an elevated nutrient load and warmer than normal temperatures. Concentrations of nutrients, especially NH4 +, urea, PO4 3?, and organic nitrogen and phosphorus, were manyfold higher than observed in the year prior or since. These findings suggest that mesoscale features were important in bloom dynamics more regionally, but locally the bloom was sustained by nutrient enrichment supplemented by its mixotrophic capabilities. 相似文献