Settlement Analysis of Açu Dam,Brazil     

de Souza  Andriele Nascimento  da Silva  Aline Ribeiro  Santos  Olavo F.  de Freitas Neto  Osvaldo 《Geotechnical and Geological Engineering》2022,40(3):1565-1583

Geotechnical and Geological Engineering - The Armando Ribeiro Gonçalves Dam, popularly known as The Açu Dam, is an important geotechnical construction in Rio Grande do Norte state,...  相似文献   

Suitability of GNSS for analysis of soil subsidence in Recife in a highly urbanized coastal area     

de Luna  Rejane Maria Rodrigues  dos Anjos Garnés  Silvio Jacks  da Silva Pereira Cabral  Jaime Joaquim  dos Santos  Sylvana Melo 《Natural Hazards》2021,106(3):1821-1837

Natural Hazards - Recife Metropolitan Region, in the northeast of Brazil, is formed by a coastal plain bounded by hills and by the Atlantic Ocean. Recife Metropolitan Region has about 4 million...  相似文献   

Land use and land cover dynamics in Leiria City: relation between peri-urbanization processes and hydro-geomorphologic disasters     

Barros  José Leandro  Tavares  Alexandre Oliveira  Santos  Pedro Pinto 《Natural Hazards》2021,106(1):757-784

Natural Hazards - The objective of the present study is to evaluate the relation between the spatial and temporal dynamics of Land Use and Land Cover (LULC) and the hydro-geomorphological processes...  相似文献   

Reply to Discussion “Geopolymers Based on Recycled Glass Powder for Soil Stabilization” Jair de Jesús Arrieta Baldovino,Ronaldo Luis dos Santos Izzo,Juliana Lundgren Rose,and Mônica Angélica Avanci     

de Jesús Arrieta Baldovino  Jair  dos Santos Izzo  Ronaldo Luis  Rose  Juliana Lundgren  Avanci  Mônica Angélica 《Geotechnical and Geological Engineering》2021,39(6):4655-4657

Geotechnical and Geological Engineering -  相似文献   

Core Jamming in Unconsolidated Formations     

Peixoto Filho  Flávio Tito  Vargas Junior  Euripedes do Amaral  Santos  Erick Slis Raggio  Ferreira  Francisco Henriques 《Geotechnical and Geological Engineering》2021,39(6):4127-4142

Geotechnical and Geological Engineering - In coring operations, core jamming is a permanent concern, taking place when the rock core sample becomes stuck within the inner core barrel, thus...  相似文献   

Ray-traced slant factors for mitigating the tropospheric delay at the observation level   总被引：3，自引：2，他引：1  

Landon?UrquhartEmail author  Felipe?G.?Nievinski  Marcelo?C.?Santos 《Journal of Geodesy》2012,86(2):149-160

Three-dimensional ray tracing through a numerical weather model has been applied to a global precise point positioning (PPP) campaign for modeling both the elevation angle- and azimuth-dependence of the tropospheric delay. Rather than applying the ray-traced slant delays directly, the delay has been parameterized in terms of slant factors, which are applied in a similar manner to traditional mapping functions, but which can account for the azimuthal asymmetry of the delay. Five strategies are considered: (1) Vienna Mapping Functions 1 (VMF1) and estimation of a residual zenith delay parameter; (2) VMF1, estimation of a residual zenith delay and estimation of two tropospheric gradient parameters; (3) three-dimensional ray-traced slant factors and estimation of a residual zenith delay; (4) using only ray-traced slant factors and no estimation of any tropospheric parameters and; (5) using both ray-traced slant factors and estimating a residual zenith delay and two tropospheric gradient parameters. The use of the ray-traced slant factors (solution 3) showed a 3.8% improvement in the repeatability of the up component when compared to the assumption of a symmetric atmosphere (solution 1), while the estimation of two tropospheric gradient parameters gave the best results showing an 7.6% improvement over solution 1 in the up component. Solution 4 performed well in the horizontal domain, allowing for sub-centimeter repeatability but the up component was degraded due to deficiencies in the modeling of the zenith delay, particularly for stations located at equatorial latitudes. The magnitude of the differences in the mean coordinates between solution 2 and solution 3, and the strong correlation with the differences between the north component and the ray-traced gradients (coefficient of correlation of 0.83), as well as the impact of observation geometry on the gradient solution indicate that the use of the ray-traced slant factors could have an implication on the realization of reference frames. The estimated tropospheric products from the PPP solutions were compared to those derived from ray tracing. For the zenith delay, a root mean square (RMS) of 5.4 mm was found, while for the gradient terms, a correlation coefficient of 0.46 for the N–S and 0.42 for the E–W was found for the north–south and east–west components, suggesting that there are still important differences in the gradient parameters which could be due to either errors in the NWM or to non-tropospheric error sources leaking into the PPP-estimated gradients.  相似文献   

High-pressure neutron diffraction study on H–D isotope effects in brucite     

Juske Horita  António M. dos Santos  Christopher A. Tulk  Bryan C. Chakoumakos  Veniamin B. Polyakov 《Physics and Chemistry of Minerals》2010,37(10):741-749

A neutron powder diffraction study of hydrogenated and deuterated brucite was conducted at ambient temperature and at pressures up to 9 GPa, using a Paris–Edinburgh high-pressure cell at the WAND instrument of the ORNL High Flux Isotope Reactor. The two materials were synthesized by the same method and companion measurements of neutron diffraction were conducted under the same conditions. Our refinement results show that the lattice-parameters of the a axis, parallel to the sheets of Mg–O octahedra, decrease only slightly with pressure with no effect of H–D substitution. However, the c axis of Mg(OD)₂ is shorter and may exhibit greater compressibility with pressure than that of Mg(OH)₂. Consequently, the unit-cell volume of deuterated brucite is slightly, but systematically smaller than that of hydrogenated brucite. When fitted to a third-order Birch–Murnaghan equation in terms of the normalized unit-cell volume, values of the bulk modulus for hydrogenated and deuterated brucite (K ₀ = 39.0 ± 2.8 and 40.4 ± 1.3 GPa, respectively) are, however, indistinguishable from each other within the experimental errors. The measured effect of H–D substitution on the unit-cell volume also demonstrates that brucite (and other hydrous minerals) preferentially incorporate deuterium over hydrogen under pressure, suggesting that the distribution of hydrogen isotopes in deep-earth conditions may differ significantly from that in near-surface environments.  相似文献   

Integrated spectroscopic study of 7 star clusters in the Small Magellanic Cloud     

M.L. Talavera  A.V. Ahumada  J.F.C. Santos  Jj. Clari  E. Bica  M.C. Parisi  M.C. Torres 《Astronomische Nachrichten》2010,331(3):323-329

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Efforts to reduce sea turtle bycatch in the shrimp fishery in Northeastern Brazil through a co-management process     

Augusto César Coelho Dias da Silva  Jaqueline Comin de Castilhos  Erik Allan Pinheiro dos Santos  Luciana Sonnewend Brondízio  Leandro Bugoni 《Ocean & Coastal Management》2010,53(9):570-576

The neritic waters of the state of Sergipe in Northeastern Brazil is adjacent to the main nesting area of the olive ridley sea turtles (Lepidochelys olivacea) in the Western Atlantic Ocean and an important area for shrimp trawl fishery. To address the problem of incidental mortality of sea turtles captured during trawling and reduce the risk of overexploitation of shrimp stocks, Projeto TAMAR/ICMBio, a Brazilian sea turtle conservation program, has adopted two main strategies: (1) the implementation of a marine monitoring program and (2) active participation in local forums. This paper describes the conflicts among stakeholders, the arrangements and established mechanisms of negotiation aimed to protect sea turtles and shrimp grounds, and strategies to reduce conflicts between user groups. The analysis of this co-management process highlights the importance of stakeholder participation in resource management decision-making through a cooperative process, the role assumed by non-governmental organizations as mediators, and the factors that influence this system. The key factors and actions learnt from the current study include clear identification of the conflicts, identification of stakeholders – both local and external, and local leaders, encouragement of actors and leaders to participate, support and strengthening of local groups, legitimization of the discussion forums through involvement with government, formalization of decisions taken through legislation, and monitoring of the management efficacy.  相似文献   

Gold deposits of the Carajás mineral province: deposit types and metallogenesis     

Raimundo NetunoVillas  Marcio Santos 《Mineralium Deposita》2001,36(3-4):300-331

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