A Study on the Surface Wettability of Clastic Rocks with Potential Application for CO2 Storage Sites

Natural Resources Research - There have been many studies carried out in the past decades attempting to develop strategies for a safe injection of CO2 into storage sites without leakage and...     

Longitudinal dispersion compensation for the Very Large Telescope Interferometer

The Very Large Telescope Interferometer [1,13] will be operated in air which will introduce small optical path fluctuations due to internal turbulence [4,6] and dispersion effects. Both may contribute to fringe contrast decrease. Longitudinal dispersion effects can be corrected by inserting an appropriate glass of variable thickness in one arm of the interferometer [3,5,11,12]. This paper presents a new method applied to VLTI in order to select the optimum glass, according to both the observing wavelength and the spectral bandpath, and to calculate its thickness. Results are presented in terms of improvement on the fringe contrast.     

Determinants and characteristics of female migration: a case study of Salem City in Tamil Nadu,India

A random sample of 521 male and 481 female migrants surveyed in Salem city in Tamil Nadu, India, during 1980-1981 was analyzed on the basis of a classification related to reasons (association, marriage, distress, and voluntary) for migration. Women were found to outnumber males in associational migration, both in rural to urban and urban to urban streams. They also formed almost all the marriage migrants. They were more numerous in distress migration as well. There were, however, comparatively few women among voluntary migrants. The incidence of illiteracy among migrant women was generally high, except for voluntary migrants who had completed high school. The share of working women was not negligible, but in most cases present work status was achieved after migrating.     

Assessment of sandstone deterioration at Ta Keo temple (Angkor): first results and future prospects

A first application of geomorphological methods to the assessment of sandstone deterioration at Angkor is presented. Damage diagnosis was carried out on the first eastern tier of the central pyramid of the 1,000 year-old Ta Keo temple. Methods combine field observations and measurements at 230 sampling points, high-resolution lasergrammetry and stereophotogrammetry on a 2-m² test zone, and SEM observations. The first results indicate that decay operates through a synergistic combination of weathering phenomena dominated by scaling and solution, and exhibits a high spatial variability. Percentages of deteriorated surfaces vary from 17.6 to 93.8%, and average stone recession values from 0.00 to 2.71 cm (minimum) and 0.34 to 5.49 cm (maximum). On the test-zone, stereophotogrammetry and 3D-mapping of the present and reconstructed initial states using lasergrammetry indicate that erosion scars up to 6 cm deep have formed since 1963. On the whole, the amount of deteriorated surfaces more than tripled between 1963 and 2008. The degree of implication of salts in stone decay remains unclear for most efflorescences are composed of calcite (CaCO3), with secondary importance of barite (BaSO4) and gypsum (CaSO₄·2H₂O). Future prospects aim to evaluate the impact on stone decay of the clearing out of the temple from the forest in the 1920s.     

Flexural isostatic response of the Alps to increased Quaternary erosion recorded by foreland basin remnants,SE France

We test the hypothesis that flexural isostatic compensation of the mass removed by enhanced Quaternary erosion is responsible for uplift of the Western European Alps and their forelands. We use two well‐preserved and well‐dated (1.8 Ma) abandonment surfaces of foreland basin remnants in SE France (the Chambaran and Valensole plateaux) as passive benchmarks for tilting of the foreland. Estimating their initial slope from morphometric scaling relationships, we determine bulk post‐depositional tilting of 0.5–0.8% for these surfaces. The calculated isostatic response of the Alpine lithosphere to erosional unloading, using the method recently proposed by Champagnac et al. [Geology 35 (2007) 195–198] , yields a predicted tilting of 0.3–0.4% in the considered areas, explaining approximately half of the determined post‐depositional tilting. Such long‐term deformation being insensitive to cyclic loading/unloading because of glaciations, we suspect the other half to be related to as yet undetermined long‐wavelength and long‐lived tectonic process(es).     

Microbiological and chitinoclastic activities associated withPenaeus setiferus

Analysis of microbiological and chitinase activities relative to the white shrimpPenaeus setiferus, and its chitinoclastic endosymbionts, have demonstrated the relevance of total chitinolytic processes in penaeid biology. Microorganisms may serve as a direct source of nutrients for the animal as well as in the elaboration of extracellularin situ chitinase enzymes. The enzyme produced by the predominant gut bacteria,Beneckea neptuna, is a moderately actively inducible chitinase while the shrimp has an indigenous constitutive chitinase and chitobiase system. Factors of temperature, pH, ion inhibition and reducing sugar ratios have been compared for the bacterial and animal enzymes. This dual enzyme system suggests that metabolic chitin transformation may play a vital role in crustacean metabolism.     

Inertial and hydrodynamic inertial loads on floating units

The analysis of the dynamic behavior of floating units usually employs a coordinate system with origin in the unit's center of gravity, which significantly simplifies the global mass matrix. Hydrodynamic coefficients are then computed considering the same coordinate system. However, to analyze other conditions of mass distribution and maintain the simplicity of a global mass matrix, it is necessary to determine again the hydrodynamic coefficients, thereby reducing the efficiency of the entire process. Another important point is that the geometries frequently used in floating units are such that the cross-terms of an added mass are relatively unimportant when compared with the main terms, and it is, therefore, common to use only some of them to analyze the unit's dynamic behavior. Recently, however, in the search for production systems suitable for water depths greater than 3000 m, other geometries have been considered in technical and economic feasibility studies. It is possible that for these new geometries all terms of the added mass matrix must be included in the analysis. This paper presents the full development used to determine the complete global mass matrix, the inertial and hydrodynamic inertial loads that make use of the added mass matrices considering any coordinate system and the six degrees of freedom, including all cross-terms.     

Nutrient budgets and trophic state in a hypersaline coastal lagoon: Lagoa de Araruama, Brazil

Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline lagoon with salinity varying spatially from 45 to 56. We collected water samples during monthly cruises throughout the lagoon, and along the streams feeding the system, from April 1991 to March 1992. Nutrients and other water quality parameters exhibited great spatial and temporal variations. Mass balance calculations indicate large amounts of anthropogenic nutrient inputs. The data indicate that the lagoon currently is oligotrophic but is in a state of transition to become a mesotrophic system. Molar dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN/DIP) varied between 2.2:1 and 659:1 with a volume-weighted average of 22:1. The high DIN/DIP ratio contrasts with that found in nearby lagoons, suggesting that phytoplankton primary production is limited by phosphorus in Lagoa de Araruama. The major loss of DIP is apparently driven by biological assimilation and diagenic reactions in the sediments. Calculations indicate that the lagoon is slightly net autotrophic at +0.9 mol C m⁻² yr⁻¹. This suggests that the biomass of the primary producers is restricted by phosphorus availability. Phosphorus retention in the sediment and the hypersaline state of the lagoon prevent changes in autotrophic communities and the formation of eutrophic conditions.