Grain scale simulation of flow in a sandstone sample by using the moving particle semi-implicit (MPS) method

Since the grain scale modelling of flow in porous media is of great interest for the oil industry, the aim of the present research is to show an application of Moving Particle Semi-Implicit (MPS) method to the grain scale simulation of fluid flow in porous media. Geometry data obtained by a high-resolution CT scan of a reservoir sandstone sample was used as input for the simulations. The results of the simulations performed considering different resolutions are given, as well as the head loss and permeability obtained numerically

A coupled analysis of sloshing in floating structures by integrating moving particle semi-implicit (MPS) method with a time domain multibody dynamic analysis software

Sloshing effects inside partially filled tanks on LNG carriers and FPSOs motions cannot be ignored. It is necessary to analyze the floating structures motion with the sloshing behavior simultaneously to obtain more accurate stability predictions because the phenomenon may affect the safety and the operability of the vessels in seaways and during loading and offloading process. In the present study, in order to model the coupled effects of platforms motion in waves and the liquid sloshing inside its tank, a hybrid timedomain simulation approach based on the integration of two simulators is proposed. The Numerical Offshore Tank (TPN) simulator, which is a time domain multibody dynamic analysis software, is used for the simulation of open domain hydrodynamic forces. It is able to perform calculations of coupled floating structures motion with the dynamic of mooring and connection lines and risers considering environmental condition such as wave, current and wind. In the other hand, due to the highly nonlinear aspect of the sloshing phenomenon, the Moving Particle Semi-implicit (MPS) method, which demands huge computing resources and it is more suitable to confined domain problems, is used to simulate the sloshing motion and to calculate the loads on the tank walls. The effects due to sloshing is then feed-backed to the TPN simulator as additional force and moment to solve the motion equation of the floating structure. The calculation can be distributed in a PCs cluster and each sloshing tank is solved in a different node. In this way, it allows the calculation of many tanks without increasing the computational time. Simulations were carried out with and without considering the coupled sloshing motions, and the results were compared to assess the effects of the liquid cargo sloshing on the motion of the floating structure

Firing temperature determination and thermoluminescence dating of a brick with cuneiform characters found in the ruins of Ancient Babylon

Este artigo tem por objetivo estudar um tijolo com inscrições em caracteres cuneiformes cujas sentenças estão praticamente completas. Estudos tipológicos correspondentes aos relatos históricos sugerem que o tijolo foi manufaturado no século VI a.C., durante a dinastia de Nabucodonosor II, grande monarca da Babilônia. A amostra foi estudada através da difração de raios X (DRX), ressonância paramagnética de elétron (RPE), termoluminescência (TL) e técnicas de análise por ativação instrumental com nêutrons (AAIN). Os resultados demonstraram que o tijolo tem 2350 anos de idade (± 40) e queima menor que 400o C.This paper aims to study a brick with inscriptions in cuneiform characters in  which the sentences are almost complete. Typological studies in agreement with historical records suggest that the tablet was manufactured in the 6th century  BCE during the dynasty of Nebuchadnezzar II, Great King of Babylon. The  sample was studied by X-ray diffraction analysis (XRD), electron paramagnetic resonance (EPR), thermoluminescence (TL), and instrumental neutron activation analysis (INAA) techniques. The results showed that the brick is 2350 years old (± 40) and its firing temperature was lower than 400 °C

Compatibilization mechanism induced by organoclay in PMMA/PS blends

International audienc

Grain scale simulation of flow in a sandstone sample by using the moving particle semi-implicit (MPS) method

Since the grain scale modelling of flow in porous media is of great interest for the oil industry, the aim of the present research is to show an application of Moving Particle Semi-Implicit (MPS) method to the grain scale simulation of fluid flow in porous media. Geometry data obtained by a high-resolution CT scan of a reservoir sandstone sample was used as input for the simulations. The results of the simulations performed considering different resolutions are given, as well as the head loss and permeability obtained numerically

Estudo das propriedades térmicas e reológicas de PLA reforçado com nanowhiskers de celulose.

No presente trabalho foram obtidos nanowhiskers de celulose (NCs) por meio da hidrólise ácida com ácido sulfúrico, os quais foram caracterizados por DRX e TGA. A incorporação dos NCs em matriz de PLA em estado fundido foi feita através de câmara de mistura e prensagem. As amostras foram caracterizadas por DSC, microscopia óptica e por análises reologias. Os resultados de DSC e microscopia mostraram que os NCs alteraram o processo de cristalização do PLA. Os ensaios reológicos de cisalhamento oscilatório de pequenas amplitudes (COPA) mostraram que a adição de 3% em massa de NCs no PLA foi suficiente para alterar o comportamento reológico do polímero.CAPESFAPES

A coupled analysis of sloshing in floating structures by integrating moving particle semi-implicit (MPS) method with a time domain multibody dynamic analysis software

Sloshing effects inside partially filled tanks on LNG carriers and FPSOs motions cannot be ignored. It is necessary to analyze the floating structures motion with the sloshing behavior simultaneously to obtain more accurate stability predictions because the phenomenon may affect the safety and the operability of the vessels in seaways and during loading and offloading process. In the present study, in order to model the coupled effects of platforms motion in waves and the liquid sloshing inside its tank, a hybrid timedomain simulation approach based on the integration of two simulators is proposed. The Numerical Offshore Tank (TPN) simulator, which is a time domain multibody dynamic analysis software, is used for the simulation of open domain hydrodynamic forces. It is able to perform calculations of coupled floating structures motion with the dynamic of mooring and connection lines and risers considering environmental condition such as wave, current and wind. In the other hand, due to the highly nonlinear aspect of the sloshing phenomenon, the Moving Particle Semi-implicit (MPS) method, which demands huge computing resources and it is more suitable to confined domain problems, is used to simulate the sloshing motion and to calculate the loads on the tank walls. The effects due to sloshing is then feed-backed to the TPN simulator as additional force and moment to solve the motion equation of the floating structure. The calculation can be distributed in a PCs cluster and each sloshing tank is solved in a different node. In this way, it allows the calculation of many tanks without increasing the computational time. Simulations were carried out with and without considering the coupled sloshing motions, and the results were compared to assess the effects of the liquid cargo sloshing on the motion of the floating structure

Stress relaxation behavior of PMMA/PS polymer blends

In this work, the stress relaxation behavior of PMMA/PS blends, with or without random copolymer addition, submitted to step shear strain experiments in the linear and nonlinear regime was studied. The effect of blend composition (ranging from 10 to 30 wt.% of dispersed phase), viscosity ratio (ranging from 0.1 to 7.5), and random copolymer addition (for concentrations up to 8 wt.% with respect to the dispersed phase) was evaluated and correlated to the evolution of the morphology of the blends. All blends presented three relaxation stages: a first fast relaxation which was attributed to the relaxation of the pure phases, a second one which was characterized by the presence of a plateau, and a third fast one. The relaxation was shown to be faster for less extended and smaller droplets and to be influenced by coalescence for blends with a dispersed phase concentration larger than 20 wt.%. The relaxation of the blend was strongly influenced by the matrix viscosity. The addition of random copolymer resulted in a slower relaxation of the droplets.FAPESPCNPqCAPE

The role of Late Pleistocene-Holocene tectono-sedimentary history on the origin of patches of savanna vegetation in the middle Madeira River, southwest of the Amazonian lowlands

Savanna patches are features of the Amazonian landscape that have been long under intense debate, but there are still questions about the main factors that have determined their establishment and evolution within the rainforest matrix. In particular, their geological substrates were poorly documented. The aim of this work is to reconstruct the tectono-sedimentary history of four savanna patches in the middle Madeira River, southwest Amazonia, and discuss its potential control over the development of the savanna communities. The approach consisted in the integration of geomorphological, sedimentological, chronological and floristic data. The results revealed that the savanna substrates are sandy deposits aged between 118.9 and 35.6 ky, overlain by late Pleistocene to Holocene muddier successions <25,700 cal yr BP. Most of the geologically stable and topographically higher terrains of the geomorphological unit T1 is dominated by forests. These intermingle with open habitats formed by renewed sedimentation that were colonized by tree and shrub species of the Amazonian biome. By contrast, the ground of unit T2 subsided to a level that allowed the meandering of the main river. This process resulted in the replacement of the rainforest by open habitats dominated by savannas with lower richness and diversity than in the T1 unit, which were dominated by species with wide distribution in the cerrado biome of Central Brasil. The cerrado species might have expanded into this region during Pleistocene drier climatic episodes, but environmental filters shaped by geological processes determined the floristic contrasts between units T1 and T2. The lack of competition with Amazonian species probably constituted an important factor for the preferential colonization of arboreal and shrubby species from neighboring cerrados on meandering scroll bars, marginal levees and crevasse splays of unit T2. © 2019 Elsevier B.V