Polymer flooding in a high salinity heavy-oil reservoir

This work aims to present a methodology to evaluate polymer flooding and compare the results with the conventional waterflooding for a target heavy oil reservoir. The dead oil and produced water (SPW) (104 800 ppm of total solids dissolved) were prepared to represent the reservoir fluids at test conditions (60°C). SPW was the water source to make and determine the polymer concentration (HPAM-ATBS) to get the target viscosity for the injection fluid (10 mPa s at 7.8 s-1). Botucatu sandstone samples represented the reservoir formation. We verified the thickness of the polymer solution after flow throughout the rock sample and confirmed higher value than that for injected SPW. Polymer flooding led to the breakthrough delay, shifted the fractional flow to the right, anticipated oil production, and incremented oil recovery. Under the tested conditions, the maximum contribution of polymer flooding occurred up to 70% of water cut121355

Tolerância de ovinos ao hidróxido de sódio e/ou sódio residual contido em cama de frangos de corte.

Resumo: Foram utilizados 18 ovinos da raca Corriedale, num delineamento em blocos inteiramente casualizados, com um arranjo fatorial 2 x 3, dois tipos de cama de frangos de corte, cama de casca de arroz (CCA) e cama de palha de arroz (CPA) e tres niveis de NaOH (zero, 6% e 12%). O consumo de sodio, consumo de agua, producao urinaria e a relacao de Na: Kurinaria foram significativamente (P0,05). O pH da urina mostrou tendencia a se elevar somente a medida que foram aumentados os niveis de alcali na dieta dos animais. O pH ruminal parece nao ter sido afetado pelo consumo das dietas tratadas com NaOH. O balanco de sodio foi negativo e inversamente relacionado com o consumo deste mineral, nao havendo dados suficientes que permitam a explicacao deste fato. [Sheep tolerance to sociu hydroxide and/or residual contents in the broiler litter]. Sheep tolerance to sodium hydroxide (NaOH) treated diets was studied. Eighteen Corriedale sheep were used in a completely randomized block design, witha 2 x 3 factorial arrangement. The design included two types of brolier litter lone composed of rice huiis and the other one of rice straw) and three leveis of NaOH (zero, 6% and 12%). Water and Na intakes, urine excretion and Na: K urinary ratio, increased (P 0.05) when yield increased. The urine pH showed only a tendency of increasing when the alkaii treatment in the animal diet increased. No effect of the NaOH treatments on the ruminal pH was detected. Sodium balance was negative and inversely related to the Na intake. However, there were not enough data fora ciear explanation of this fact

Non-Gaussian velocity distributions - The effect on virial mass estimates of galaxy groups

We present a study of 9 galaxy groups with evidence for non-Gaussianity in their velocity distributions out to 4R200. This sample is taken from 57 groups selected from the 2PIGG catalog of galaxy groups. Statistical analysis indicates that non-Gaussian groups have masses significantly higher than Gaussian groups. We also have found that all non-Gaussian systems seem to be composed of multiple velocity modes. Besides, our results indicate that multimodal groups should be considered as a set of individual units with their own properties. In particular, we have found that the mass distribution of such units are similar to that of Gaussian groups. Our results reinforce the idea of non-Gaussian systems as complex structures in the phase space, likely corresponding to secondary infall aggregations at a stage before virialization. The understanding of these objects is relevant for cosmological studies using groups and clusters through the mass function evolution.Comment: 5 pages, 4 figures and 2 tables. Accepted for publication in the MNRA

How Does a Fundamental String Stretch its Horizon?

It has recently been shown that if we take into account a class of higher derivative corrections to the effective action of heterotic string theory, the entropy of the black hole solution representing elementary string states correctly reproduces the statistical entropy computed from the degeneracy of elementary string states. So far the form of the solution has been analyzed at distance scales large and small compared to the string scale. We analyze the solution that interpolates between these two limits and point out a subtlety in constructing such a solution due to the presence of higher derivative terms in the effective action. We also study the T-duality transformation rules to relate the moduli fields of the effective field theory to the physical compactification radius in the presence of higher derivative corrections and use these results to find the physical radius of compactification near the horizon of the black hole. The radius approaches a finite value even though the corresponding modulus field vanishes. Finally we discuss the non-leading contribution to the black hole entropy due to space-time quantum corrections to the effective action and the ambiguity involved in comparing this result to the statistical entropy.Comment: LaTeX file, 38 pages; v2: minor changes and added reference

Non-parametric comparison of histogrammed two-dimensional data distributions using the Energy Test

When monitoring complex experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger HEP experiments now ramping up, there is a need for automation of this task since the volume of comparisons could overwhelm human operators. However, the two-dimensional histogram comparison tools available in ROOT have been noted in the past to exhibit shortcomings. We discuss a newer comparison test for two-dimensional histograms, based on the Energy Test of Aslan and Zech, which provides more conclusive discrimination between histograms of data coming from different distributions than methods provided in a recent ROOT release.The Science and Technology Facilities Council, U

Processamento mínimo de mini beterraba.

bitstream/CNPH-2010/36377/1/cot-73.pd

Spectrally narrow exciton luminescence from monolayer MoS2 exfoliated onto epitaxially grown hexagonal BN

The strong light-matter interaction in transition Metal dichalcogenides (TMDs) monolayers (MLs) is governed by robust excitons. Important progress has been made to control the dielectric environment surrounding the MLs, especially through hexagonal boron nitride (hBN) encapsulation, which drastically reduces the inhomogeneous contribution to the exciton linewidth. Most studies use exfoliated hBN from high quality flakes grown under high pressure. In this work, we show that hBN grown by molecular beam epitaxy (MBE) over a large surface area substrate has a similarly positive impact on the optical emission from TMD MLs. We deposit MoS$_2$ and MoSe$_2$ MLs on ultrathin hBN films (few MLs thick) grown on Ni/MgO(111) by MBE. Then we cover them with exfoliated hBN to finally obtain an encapsulated sample : exfoliated hBN/TMD ML/MBE hBN. We observe an improved optical quality of our samples compared to TMD MLs exfoliated directly on SiO$_2$ substrates. Our results suggest that hBN grown by MBE could be used as a flat and charge free substrate for fabricating TMD-based heterostructures on a larger scale.Comment: 5 pages, 3 figure