scholarly journals Hydrogeochemical characterization of reservoir waters undergoing salinization processes in Northeastern Brazil

RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
José do Patrocinio Hora Alves ◽  
Maria Hortência Rodrigues Lima ◽  
Josefa Raimunda Dória ◽  
Igor Santos Silva ◽  
Adnivia Santos Costa Monteiro

ABSTRACT The geochemical processes that potentially control the chemical characteristics of the waters of three reservoirs located in the state of Sergipe, Northeastern Brazil, were evaluated using the Gibbs diagram, correlation analysis, ionic ratios and geochemical modeling. The results of the reverse geochemical modeling applied between two water samples from each reservoir were in agreement with the observations of the correlation analysis and ionic ratios, which indicated sea salt dissolution, silicate weathering and, to a lesser extent, carbonate dissolution, as the main geochemical processes responsible for the chemical characteristics of the waters of the three reservoirs, also confirming the importance of ion exchange for the Macela and Ribeirópolis reservoirs. These findings therefore suggest that the growing salinization process of the reservoirs is mainly controlled by water-rock interactions and may also be influenced by contributions from evaporation and anthropogenic inputs.

Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.


Ecohydrology ◽  
2011 ◽  
Vol 4 (4) ◽  
pp. 597-607 ◽  
Author(s):  
V. Marconi ◽  
M. Antonellini ◽  
E. Balugani ◽  
E. Dinelli

Author(s):  
Ana Veruska Cruz da Silva ◽  
Jéssica Monalisa S. P. Oliveira ◽  
Milena Nascimento Cardoso ◽  
Ana Letícia Sirqueira Nascimento ◽  
Tássia Fernanda S. N. Soares ◽  
...  

Author(s):  
Rafael Nakamura-Silva ◽  
Mariana Oliveira-Silva ◽  
João Pedro Rueda Furlan ◽  
Eliana Guedes Stehling ◽  
Carlos Eduardo Saraiva Miranda ◽  
...  

2013 ◽  
Author(s):  
T. Mikunthan ◽  
M. Vithanage ◽  
S. Pathmarajah ◽  
S. Arasalingam ◽  
R. Ariyaratne ◽  
...  

2006 ◽  
Vol 05 (3) ◽  
pp. 8-20
Author(s):  
José Carlos Oliveira SANTOS ◽  
Lionete Dantas NUNES ◽  
Sylvia Berenice NÓBREGA ◽  
Dantas José Pires PUZINSKI ◽  
Antonio Gouveia SOUZA

A thermal analysis has been applied to characterization of food and food products. Taking into account the problems of desertification and agricultural practices able to provide income to the population at the semi-arid region of Northeastern Brazil, this work presents the results of the chemical, thermal and kinetic characterization by thermogravimetry and differential scanning calorimetry of the seed derivatives of favelone (cnidoscolus quercifolius), aiming at the application of these materials as an alternative of food source for animals and for the human population at this brazilian region.


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