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A simplified version of a volumetric apparatus for gas/liquid solubility measurements is proposed. The procedure familiarizes undergraduate students with the experimental study of the solubility of a gas in a liquid and contributes to the understanding of this important phase equilibrium concept. The experimental results report the determination of the solubility of carbon dioxide and nitrous oxide in water, in the temperature range [290 - 303K]. The accuracy of the method was found to be about 1% which is quite acceptable for didactic purposes. The determination of the solubility uncertainty provides use of the propagation law of errors, and enables the student to evaluate which of the experimental uncertainties affect more the final result. (Contains 2 tables and 3 figures.)

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In prestressed concrete, due to the application of the prestressing force, the anchorages zones are subjected to high stresses. Along a stretch, called anchorage zone, the distribution of these stresses is not uniform, with transversal stress acting in the structural element. To resist the transverse stresses, it is necessary to adopt complementary reinforcement, called anchorage zone reinforcement. In this context, this paper aimed to investigate the behavior and distribution of stresses along the regularization length of prestressed elements, numerically evaluating in the Abaqus® software the influence and importance of anchorage zone reinforcement on such elements. For this purpose, four numerical models were simulated, VE, VEF-3, VEF-4 and VEF-5, with the same area of longitudinal and transversal reinforcement, differing in the fact that the VEF-3, VEF-4 and VEF-5 have, respectively, 3, 4 and 5 additional stirrups at each end of the beam. It was found that the insertion of the additional stirrups did not promote significant changes in the compression failure in the anchorage region, however it did promote relevant reductions in the failure in the traction. In addition, in the VE model, the value of the stress in the armature reached the yield strength of the steel, while in the models VEF-3, VEF-4 and VEF-5 the stresses reduced 19.48%, 56.58% and 57.96 % in relation to VE. This fact highlights the importance of anchorage zone reinforcement to assegurate the safety of unbonded post-tensioned beams. [ABSTRACT FROM AUTHOR]

The article presents a laboratory experiment for the determination of the solubility of gas in a liquid. It cites that the solubility of gases in liquids can be a tool to investigate solute-solvent intermolecular forces in the liquid state. A volumetric method is used in the determination of the solubility of gas in a liquid. The authors advise the use of an equilibrium vessel with a greater volume when opting for less soluble gases.

The article provides molecular characterization of measles viruses detected in an outbreak in the northeast region of Brazil from 2013-2015 including measles caused by RNA virus, identification of 24 different measles genotypes, and first detection of measles virus in Pernambuco.