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Steady and time dependent natural convection of water confined in a vertical cylindrical container heated from below is studied experimentally and numerically. The container has a circular cross-section and an aspect ratio (height/diameter) of 1.25. Convective motions are analyzed for a constant Prandtl number of 6.7 and a range of Rayleigh numbers from 3.0 × 10 5 to 2.0 × 10 6 . These conditions include steady and time-dependent flows and in all cases, flow patterns present complex three-dimensional structures. Experimental observations were made with a composed PIV system capable of simultaneously obtaining velocity distributions in two mutually perpendicular planes. The numerical model comprises the solution of the three-dimensional time-dependent Boussinesq equations in cylindrical coordinates. Experimental observations are compared with the numerical model and a satisfactory agreement is obtained for steady flow and averaged values in unsteady flow. The general structure of the present study follows the procedure required for the verification of the numerical model and its validation with experimental observations.

The elaboration of bilayerTiO2/CNTfilms dried under terrestrial gravity conditions (g) and on a centrifuge with 1.3gand 7gis reported. The changes in microstructure and thickness of these coatings under supergravity environment cause a red-shift tendency in the optical properties at increasing values of acceleration. Experiments of a drop under enhanced gravity force in the range of 3.7 < Bo (bond number) < 51.5 suggest the incomplete elimination of surfactant-water molecules in theTiO2/CNTbilayer film. Increasing acceleration up to 14gwill widen the optical differences found, proving the layer-by-layer solution-chemical method in combination with these drying protocols, an alternative to produce thickness-sensitive solar-selective absorbing coatings.

We present a numerical and experimental study of steady natural convection in a small aspect ratio cylindrical cavity with circular cross section. The main objective of the present communication is to highlight some difficulties encountered when a comparison of theoretical and experimental velocity results is attempted. We keep the aspect ratio (radius/height), the Prandtl number and the Rayleigh number fixed to 0.28, 6 and 2.25 × 106 respectively and make observations in a vertical plane that contains the axis of symmetry of the cylinder with a particle image velocimetry (PIV) technique. The main structure present in the flow is a single non-axisymmetric cell with a horizontal rotation axis. Due to the symmetry of the geometry of the cavity and of the heating and cooling systems, the orientation of the convective structure is undefined by the boundaries. In order to make a theoretical-experimental comparison, it is necessary to make a full description of the three dimensional velocity field to find the plane that corresponds to the one observed in the experiment.

SUMMARYEhNCABP166 is an Entamoeba histolytica actin-binding protein that localizes to the nucleus and cytoplasm. Bioinformatic analysis of the EhNCABP166 amino acid sequence shows the presence of 3 bipartite nuclear localization signals (NLS) and a nuclear export signal (NES). The present study aimed to investigate the functionality of these signals in 3 ways. First, we fused each potential NLS to a cytoplasmic domain of ehFLN to determine whether the localization of this domain could be altered by the presence of the NLSs. Furthermore, the localization of each domain of EhNCABP166 was determined. Similarly, we generated mutations in the first block of bipartite signals from the domains that contained these signals. Additionally, we added an NES to 2 constructs that were then evaluated. We confirmed the intranuclear localization of EhNCABP166 using transmission electron microscopy. Fusion of each NLS resulted in shuttling of the cytoplasmic domain to the nucleus. With the exception of 2 domains, all of the evaluated domains localized within the nucleus. A mutation in the first block of bipartite signals affected the localization of the domains containing an NLS. The addition of an NES shifted the localization of these domains to the cytoplasm. The results presented here establish EhNCABP166 as a protein containing functional nuclear localization signals and a nuclear export signal.

We present linear perturbation analysis of the mass, momentum and energy conservation equations for a compressible fluid to obtain quantitative bounds for the validity of the Boussinesq approximation for a rotating flow. We have used the methodology developed by Gray and Giorgini [11] and generalized it to include the effects of rotation. We consider cases where the axis of rotation is contained in the body of fluid and also those where the axis of rotation is located far away from the region occupied by the fluid.

We present an experimental and numerical study of the flow patterns that occur in natural convection inside a cylindrical cavity of aspect ratio (radius to height) of 0.25. The working fluid was water with a Prandtl number of 6.0. Observations made for a cavity fixed in the laboratory frame of reference at a Rayleigh number of 2.3 × 106 indicate that the convective pattern was steady and organized in a single asymmetric cell. Observations were also made with the cavity placed in a centrifuge. Experimental visualization with a rotating cavity was made with a Rayleigh number of 2.5×106 and a Taylor number of 1.7×107. With rotation, the flow became time-dependent with two differentiated modes. In the first mode, the flow was composed of regions that seemed to move in an almost independent way during tens of seconds. Then a general motion that lasted a few seconds set in. This sequence of events repeated with varying periods.