Correlation of the liquid–liquid equilibrium data for specific ternary systems with one or two partially miscible binary subsystems

This paper presents the results of a liquid–liquid equilibrium data correlation for 11 ternary systems which have not been previously fitted using the NRTL model or, when they have, the results presented in the literature are inconsistent with the experimental behavior of the system. These ternary systems include mixtures with one or two partially miscible pairs. During the correlation process, new restrictions were imposed on the values for the NRTL binary parameters to ensure correct prediction of the total or partial miscibility for the binary pairs involved. In addition, topological concepts related to the Gibbs stability test have been applied in order to validate the results in the whole range of compositions.

Correlation of the Corneal Toricity Between Anterior and Posterior Corneal Surfaces in the Normal Human Eye

Purpose: To evaluate the correlation of the magnitude of corneal toricity and power vector components of both corneal surfaces measured with a Scheimpflug photography-based system. Methods: A total of 117 healthy normal eyes of 117 subjects selected randomly with ages ranging from 7 to 80 years were included. All eyes received an anterior segment and corneal analysis with the Sirius system (CSO) evaluating the anterior and posterior mean toricity for 3 and 7 mm (aAST and pAST). The vector components J0 and J45 as well as the overall strength blur (B) were calculated for each keratometric measurement using the procedure defined by Thibos and Horner. Results: The coefficient of correlation between aAST and pAST was 0.52 and 0.62 and the mean anteroposterior ratio for toricity was 0.46 ± 0.39 and 0.57 ± 0.75 for 3 and 7 mm, respectively. These ratios correlated significantly with aAST, anterior corneal J0, and manifest refraction J0 (r ≥ 0.39, P < 0.01). The coefficient of correlation was 0.69 and 0.81 between anterior and posterior J0 for 3 and 7 mm, respectively. For J45, the coefficients were 0.62 and 0.71, respectively. The linear regression analysis revealed that the pAST and power vectors could be predicted from the anterior corneal data (R2 ≥ 0.40, P < 0.01). Conclusions: The toricity and astigmatic power vector components of the posterior corneal surface in the human healthy eye are related to those of the anterior and therefore can be predicted consistently from the anterior toricity and astigmatic power vectors.

Correlation of Anterior and Posterior Corneal Shape in Keratoconus

Purpose: To evaluate the correlation of the mean curvature and shape factors of both corneal surfaces for different corneal diameters measured with the Scheimpflug photography–based system in keratoconus eyes. Methods: A total of 61 keratoconus eyes of 61 subjects, aged 14 to 64 years, were included in this study. All eyes received a comprehensive ophthalmologic examination including anterior segment and corneal analysis with the Sirius system (CSO): anterior and posterior mean corneal radius for 3, 5, and 7 mm (aKM, pKM), anterior and posterior mean shape factor for 4.5 and 8 mm (ap, pp), central and minimal corneal thickness, and anterior chamber depth. Results: Mean aKM/pKM ratio around 1.20 (range, 0.95–1.48) was found for all corneal diameters (P = 0.24). Weak but significant correlations of this ratio with pachymetric parameters were found (r between −0.28 and −0.34, P < 0.04). The correlation coefficient between aKM and pKM was ≥0.92 for all corneal diameters. A strong and significant correlation was also found between ap and pp (r ≥ 0.86, P < 0.01). The multiple regression analysis revealed that central pKM was significantly correlated with aKM, central corneal thickness, anterior chamber depth, and spherical equivalent (R2 ≥ 0.88, P < 0.01) and that 8 mm pp was significantly correlated with 8 mm ap and age (R2 = 0.89, P < 0.01). Conclusions: Central posterior corneal curvature and shape factor in the keratoconus eye can be consistently predicted from the anterior corneal curvature and shape factor, respectively, in combination with other anatomical and ocular parameters.

Kinetic study of the decompositions involved in the thermal degradation of commercial azodicarbonamide

The transitions and reactions involved in the thermal treatment of several commercial azodicarbonamides (ADC) in an inert atmosphere have been studied by dynamic thermogravimetry analysis (TGA), mass spectrometry and Fourier transform infrared (FTIR) spectroscopy. A pseudo-mechanistic model, involving several competitive and non-competitive reactions, has been suggested and applied to the correlation of the weight loss data. The model applied is capable of accurately representing the different processes involved, and can be of great interest in the understanding and quantification of such phenomena, including the simulation of the instantaneous amount of gases evolved in a foaming process. In addition, a brief discussion on the methodology related to the mathematical modeling of TGA data is presented, taking into account the complex thermal behaviour of the ADC.

Tectonic control on the sedimentary record of the central Moldavidian Basin (Eastern Carpathians, Romania)

The sedimentary record of the Tarcău and Vrancea Nappes, belonging to the flysch accretionary zone of the Eastern Carpathians (Eastern Carpathian Outer Flysch), registered Cretaceous-Miocene events during the evolution of the Moldavidian Basin. Our biostratigraphic data indicate that the deposits studied are younger than previously reported. The comparison of sedimentary record studied with the Late Cretaceous-Early Miocene global eustatic curve indicates that eustatic factor played a secondary role, after the tectonic one. Four main stages of different processes influenced by tectonics are recognized in the sedimentary record: (1) Campanian-Maastrichtian-earliest Paleocene; (2) latest Ypresian-Lutetian; (3) late Chattian-earliest Aquitanian, and (4) late Aquitanian-early Burdigalian. The late Chattian- earliest Aquitanian and late Aquitanian-early Burdigalian records indicate a high tectonic influence. The first event was related to the foredeep stage of the sedimentary domain studied, and the second one to the deformation stage of the same domain. The sedimentary records of tectonic influence recognized during these stages are useful tools for geodynamic reconstructions. The stratigraphic correlation of Tarcău and Vrancea sedimentary records are used