The rise of air bubbles in five Newtonian fluids is compared for two different cases of bubble formation and release: (a) directly into the five homogeneous fluids and (b) directly into a layer of distilled water underlying each one of the five liquids. It was found in Case (b) that medium-sized bubbles rise steadily through the upper liquid with an enveloping water layer of variable thickness. The influence of this water layer on the trajectory, shape, and terminal velocity of bubbles is particularly significant in low viscosity upper phases. The resulting water mass transfer per bubble through the lower density upper phase depends on viscosity and was markedly greater for the higher viscosity fluids. The behavior and the nature of the detachment of the water layers from the larger size bubbles are also presented and discussed.

Fluid flow in concentric or eccentric annular ducts have been studied for decades due to large application in medical sciences and engineering areas. This paper aims to study fully developed fluid flow in straight ducts of concentric annular geometries (circular with circular core, elliptical with circular core, elliptical with elliptical core, and circular with elliptical core) using the Galerkin-based Integral method (GBI method). The choice of method was due to the fact that in the literature it is not applied in ducts of cross-sections of the annular shape with variations between circular and elliptical. Results of different hydrodynamics parameters such as velocity distribution, Hagenbach factor, Poiseuille number, and hydrodynamic entrance length, are presented and analyzed. In different cases, the predicted hydrodynamic parameters are compared with results reported in the literature and a good concordance was obtained.

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Large-scale fluid flow in porous media demands intense computations and occurs in the most diverse applications, including groundwater flow and oil recovery. This article presents novel computational strategies applied to reservoir geomechanics.Advances are proposed for the efficient assembly of finite element matrices and the solution of linear systems using highly vectorized code in MATLAB. In the CPU version, element matrix assembly is performed using conventional vectorization procedures, based on two strategies: the explicit matrices, and the multidimensional products. Further assembly of the global sparse matrix is achieved using the native sparse function. For the GPU version, computation of the complete set of element matrices is performed with the same strategies as the CPU approach, using gpuArray structures and the native CUDA support provided by MATLAB Parallel Computing Toolbox. Solution of the resulting linear system in CPU and GPU versions is obtained with two strategies using a one-way approach: the native conjugate gradient solver (pcg), and the one provided by the Eigen library. A broad discussion is presented in a dedicated benchmark, where the different strategies using CPU and GPU are compared in processing time and memory requirements. These analyses present significant speedups over serial codes.

IntroductionHydrogen peroxide (H 2 O 2 ) plays an important role in several chemical and physical processes, evidenced in astronomy, medicine, and chemical reactions. Due its importance and diversity of applications, this molecule has been subject of several studies 1,2 . Recently, our research group has developed an analytical interpretation of noble-gases influence on hydrogen peroxide by means of a potential energy surface that involves angular and radial coordinates of noble gases. The Improved Lennard Jones (ILJ) analytical form 2 , widely applied in this kind of systems, was used in order to represent the Van der Waals interaction of noble gas and O-H bound. In this work, we present the H 2 O 2 -Ng (with Ng=He,Ne, Ar, and Kr) potential energy curves (PEC) in the excited electronic states. Furthermore, these new PEC are exploited to describe the dynamical properties (rovibrational energies and spectroscopic constants) of the H 2 O 2 -Ng systems. Methods and DiscussionIt is large known that the study of excited states is not an easy task. It request a long computational simulation time and depending on electrons quantity it may be not viable. Considering this facts, it becomes crucial cost-benefits considerations. By these assumptions, we considered H 2 O 2 + He, H 2 O 2 + Ne, H 2 O 2 + Ar, H 2 O 2 + Kr on equilibrium geometries given by Table below (geometrical definition are shown in Figure 1). Artigo Geral 66Figure 1: H 2 O 2 -Ng geometrical representation. (a) R s the distance from noble-gas and center of O-O bond. (b) θ1 and θ2 are the angles between O-H bond and y axis. Jul / Dez de 2015 Edição Especial XVIII SBQT Revista Processos Químicos 267For all complexes, we calculated the electronic energies as a function of R (from 3Å to 10Å, with 0,2Å of step) considering 15 excited states. All these calculations were performed using the TDDFT method (implemented in the NWCHEM code3), with the camqtp-00 functional and the aug-cc-pVTZ basis set. These excited electronic energies were adjusted by generalized rydberg functions, as shown in Figure 2. Then, these analytical PEC were used to determine the rovibrational energies and spectroscopic constants. for all studied systems. These properties were calculated by two different methods: Solving the nuclear Schrodinger's equation (by Discrete Variable Representation 4) and Dunham 5 method. The results obtained through Dunham and DVR methodologies are in an excellent agreement. This fact demonstrates the reliability of our study. ConclusionsIn this work, we have presented a study of the interaction among the H 2 O 2 molecule with noblegases (He, Ne, Ar, and Kr) on the excited electronic states. Analytical PEC, ro-vibrational energies and spectroscopic constants were determined considering fifteen electronic states for each system. These kind of results represent the main novelty of this work, since they are presented for first time in the literature.