A well simulator for homogeneous reservoirs based on formulations of the isogeometric boundary element method

The development of a simulator for homogeneous reservoirs with application in producer wells (represented by a sink) and the aquifer analysis is obtained by combining the Boundary Element Method (BEM), the Isogeometric Formulation using NURBS (Non Uniform Rational B-Spline) as shape functions, and also the Axisymmetric Formulation. The Isogeometric Formulation makes the discretization of geometric model (mesh generation), which is the step of numerical analysis that is more time consuming for the engineer, be no longer necessary, since the same functions that describe the geometry also approximate the field variables in the BEM. In other words, the same discretization used in the geometric model, generated in CAD (Computer Aided Design) modeling programs, also is used by the BEM. The oil and water reservoirs, as simplified models for validation of the new mathematical methodology, can be fully represented by the analysis of a plane passing through the axis of rotational (axial) symmetry. The dimension of the problem is reduced from three to two dimensions: radial and axial directions only, and all variables in the circumferential direction are assumed to be constant. When the geometry and the problem variables are both axisymmetric, then the problem is considered fully axisymmetric. The isogeometric and axisymmetric formulations are coupled to obtain the well simulator for the single and double phase case, i.e. one or two incompressible fluids inside the reservoir. The determination of boundary conditions for the model, including the analysis of fluids interface movement, is also presented. The final code is a new tool for the analysis of gas/water coning phenomenon and quick drawdown problem in homogeneous reservoirs, as validation models. Validation of the results is carried out by comparing with others numerical methods and analytical results

Evapotranspiration of the brazilian Pampa biome: seasonality and influential factors

Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that the latent heat flux was the dominant component in available energy in both the autumn–winter (AW) and spring–summer (SS) periods. Evapotranspiration of the Pampa biome showed strong seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean ET rate was 2.45 mm d1. ET did not show to vary significantly between sites, with daily values very similar in both sites. The water availability in the Pampa biome was not a limiting factor for ET, which resulted in a small difference between the reference ET and the actual ET. These results are helpful in achieving a better understanding of the temporal pattern of ET in relation to the landscape of the Pampa biome and its meteorological, soil, and vegetation characteristicsinfo:eu-repo/semantics/publishedVersio

FIRST RECORD OF A NUCLEAR-FOLLOWER ASSOCIATION BETWEEN CORYDORAS VITTATUS (NIJSSEN, 1971), CORYDORAS CF. JULII (CALLICHTHYIDAE) AND KNODUS VICTORIAE (STEINDACHNER, 1907) (CHARACIDAE)

Nuclear-follower interactions are a particular type of interspecific foraging association which involves a nuclear species, which revolves or scans through the substrate, and follower species that access the food items made available by the nuclear species’ activity. This type of association was observed in a headwater stream at the Itapecuru basin, in the Maranhão cerrado, involving the catfishes Corydoras vittatus, Corydoras cf. julii as nuclear species and Knodus victoriae as its follower. Individuals of C. vittatus, Corydoras cf. julii revolved the substrate during their foraging, promoting sediment suspension. Their followers, in turn, moved through the “cloud” of particles in suspension, capturing food items. Food particles in suspension do not seem to be used by the catfishes but become available for K. victoriae. The follower behavior represents a feeding tactic for these species, reinforcing the general idea of behavioral plasticity between follower species

Pulse-mode quantum projection synthesis: Effects of mode mismatch on optical state truncation and preparation

Quantum projection synthesis can be used for phase-probability-distribution measurement, optical-state truncation and preparation. The method relies on interfering optical lights, which is a major challenge in experiments performed by pulsed light sources. In the pulsed regime, the time frequency overlap of the interfering lights plays a crucial role on the efficiency of the method when they have different mode structures. In this paper, the pulsed mode projection synthesis is developed, the mode structure of interfering lights are characterized and the effect of this overlap (or mode match) on the fidelity of optical-state truncation and preparation is investigated. By introducing the positive-operator-valued measure (POVM) for the detection events in the scheme, the effect of mode mismatch between the photon-counting detectors and the incident lights are also presented.Comment: 11 pages, 4 figures, submitted to Phys. Rev.

Linear Response, Validity of Semi-Classical Gravity, and the Stability of Flat Space

A quantitative test for the validity of the semi-classical approximation in gravity is given. The criterion proposed is that solutions to the semi-classical Einstein equations should be stable to linearized perturbations, in the sense that no gauge invariant perturbation should become unbounded in time. A self-consistent linear response analysis of these perturbations, based upon an invariant effective action principle, necessarily involves metric fluctuations about the mean semi-classical geometry, and brings in the two-point correlation function of the quantum energy-momentum tensor in a natural way. This linear response equation contains no state dependent divergences and requires no new renormalization counterterms beyond those required in the leading order semi-classical approximation. The general linear response criterion is applied to the specific example of a scalar field with arbitrary mass and curvature coupling in the vacuum state of Minkowski spacetime. The spectral representation of the vacuum polarization function is computed in n dimensional Minkowski spacetime, and used to show that the flat space solution to the semi-classical Einstein equations for n=4 is stable to all perturbations on distance scales much larger than the Planck length.Comment: 22 pages: This is a significantly expanded version of gr-qc/0204083, with two additional sections and two new appendices giving a complete, explicit example of the semi-classical stability criterion proposed in the previous pape

Changes on movement control of dart throwing under distance and target weight constraints

The aim of the study was to verify the effects of dart weight and target distance on kinematic variables of the movement control of the underarm dart throwing task. Four women and one man performed the task of throwing a dart at two horizontal circular targets located at 2m (Nt) and 3m (Ft) away, with two different weights, 22g (Ld) and 44g (Hd). On the first phase of the experiment, the human volunteers performed 200 trials per day during four sessions. On the fifth day, it had 40 more trials in a pseudo random order that were recorded and analysed. A high precision camera recorded the kinematic variables amplitude of the movement (AOM), release height, movement time, release velocity and release angle, with a frequency of acquisition of 100 Hz. Performance was measured by the distance from the actual dart position to the target bull’s eye. The analysis revealed that increasing the mass of the dart diminished only the release angle. However, increasing the distance of the target increased in the AOM and the movement time of the arm, the release velocity of the dart and increased the absolute error. The results show that the motor control system has ability to deal with external constraints adjusting control strategies, which is represented by kinematic features. Moreover, our results suggests that varying the mass of implements, as a constraint may be a good candidate to improve the analysis for both motor control and ability during practice

Effect of graphene oxide on bacteria and peripheral blood mononuclear cells

"Background Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. Methods Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ?100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. Results A size-dependent growth inhibition of Escherichia coli (DH5 ?) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. Conclusions Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.

The cyclooxigenase-2 inhibitor parecoxib prevents epidermal dysplasia in HPV16-transgenic mice: efficacy and safety observations

Carcinogenesis induced by high-risk human papillomavirus (HPV) involves inflammatory phenomena, partially mediated by cyclooxigenase-2. In pre-clinical models of HPV-induced cancer, cyclooxygenase-2 inhibitors have shown significant e cacy, but also considerable toxicity. This study addresses the chemopreventive e ect and hepatic toxicity of a specific cyclooxigensase-2 inhibitor, parecoxib, in HPV16-transgenic mice. Forty-three 20 weeks-old female mice were divided into four groups: I (HPV16+/-, n = 10, parecoxib-treated); II (HPV16+/- n = 11, untreated); III (HPV16+/-, n = 11, parecoxib-treated) and IV (HPV16+/- n = 11, untreated). Parecoxib (5.0 mg/kg once daily) or vehicle was administered intraperitoneally for 22 consecutive days. Skin lesions were classified histologically. Toxicological endpoints included genotoxic parameters, hepatic oxidative stress, transaminases and histology. Parecoxib completely prevented the onset of epidermal dysplasia in HPV16+/- treated animals (0% versus 64% in HPV16+/- untreated, p = 0.027). Parecoxib decreases lipid peroxidation (LPO) and superoxide dismutase (SOD) activity and increases the GSH:GSSG ratio in HPV16+/- treated animals meaning that oxidative stress is lower. Parecoxib increased genotoxic stress parameters in wild-type and HPV16-transgenic mice, but didn’t modify histological or biochemical hepatic parameters. These results indicate that parecoxib has chemopreventive e ects against HPV16-induced lesions while maintaining an acceptable toxicological profile in this model.This work is supported by National Funds by FCT—Portuguese Foundation for Science and Technology, under the projects UID/AGR/04033/2019, UID/CVT/00772/2019 and UID/EQU/00511/2019 - Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE funded by national funds through FCT/MCTES (PIDDAC); Project “LEPABE-2-ECO-INNOVATION”—NORTE-01-0145-FEDER-000005, funded by Norte Portugal Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund.info:eu-repo/semantics/publishedVersio

A geometric approach to time evolution operators of Lie quantum systems

Lie systems in Quantum Mechanics are studied from a geometric point of view. In particular, we develop methods to obtain time evolution operators of time-dependent Schrodinger equations of Lie type and we show how these methods explain certain ad hoc methods used in previous papers in order to obtain exact solutions. Finally, several instances of time-dependent quadratic Hamiltonian are solved.Comment: Accepted for publication in the International Journal of Theoretical Physic