Dynamics of Scalar Field Dark Matter With a Cosh-like Potential

The dynamics of a cosmological model fueled by scalar field dark matter with a cosh-like potential plus a cosmological constant is investigated in detail. It is revealed that the late-time attractor is always the de Sitter solution, and that, depending on the values of the free parameters, the oscillating solution of the scalar field -- modeling cold dark matter -- mediates between some early stage (say, the radiation-dominated solution) and the accelerating de Sitter attractor.Comment: 9 pages, 17 figures, uses RevTe

Industry energy optimization: A case study in a biodiesel production site

This paper presents a case study of heat exchanger network (HEN) retrofit with the objective to reduce the utilities consumption in a biodiesel production process. Pinch analysis studies allow determining the minimum duty utilities as well the maximum of heat recovery. The existence of heat exchangers for heat recovery already running in the process causes a serious restriction for the implementation of grassroot HEN design based on pinch studies. Maintaining the existing HEN, a set of alternatives with additional heat exchangers was created and analysed using some industrial advice and selection criteria. The final proposed solution allows to increase the actual 18 % of recovery heat of the all heating needs of the process to 23 %, with an estimated annual saving in hot utility of 35 k(sic)/y

Spectral solution for the air stripping pollutants removal dynamic model with non linear steady state conditions

This work deals with the numerical simulation of air stripping process for the pre-treatment of groundwater used in human consumption. The model established in steady state presents an exponential solution that is used, together with the Tau Method, to get a spectral approach of the solution of the system of partial differential equations associated to the model in transient state

WG1 technical report: Performance indicators for roadway bridges of COST Action 1406

[Excerpt] SCOPE: In the past few years, significant worldwide research has been done regarding condition assessment of roadway bridges, namely through the use of non-destructive tests, monitoring systems and visual inspection techniques. Obtained values, which provide information regarding the assessed bridge state condition, are then compared with previously established goals. As a result, there are currently several methodologies to evaluate bridge condition. A similar problem was addressed with roadway pavements in the past. Although this was a worldwide problematic, in Europe it was solved through COST Action 354 (performance indicators for pavements). More recently, the concept of performance indicator was introduced, simplifying communication between consultants, operators and owners. However, large deviations continue to exist on how these indicators are obtained and, therefore, specific actions should be undertaken in order to standardize this procedure. It is verified that Quality Control (QC) plans should always address the assessed performance indicators and pre-specified goals. However, these latter values are even more difficult to obtain as they are highly subjective. (...

A new perspective for robustness assessment of framed structures

Robustness has been recognized as interesting research topic due to several collapses that have been occurring over last years. Indeed, this subject is related with global failure or collapse. However, its definition is not consensual since several definitions have been proposed in the literature. This shortpaper aims to present a framework for assessing bridge’s robustness as a probabilistic performance indicator. In this study, a non-linear model of a clamped beam with two point loads using DIANA software was developed to validate the framework presented. By means of a probabilistic approach, the load carrying capacity and structural safety were evaluated. In this regard, special focus is placed on an adaptive Monte Carlo simulation procedure to achieve a proper meta-model.ISISE – Institute for Sustainability and Innovation in Structural Engineering (PEstC/ECI/UI4029/2011 FCOM-01-0124-FEDER-022681)FCT– Portuguese Scientific Foundation for the research grant PD/BD/113677/2015European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement No. 60622

Electroanalytical study of the antidepressant sertraline

Aflowinjection squarewave cathodic stripping voltammetric method has been developed for the determination of sertraline in a pharmaceutical preparation. The method shows linearity between peak current intensity and sertraline concentration for the interval between 0.20×10−6 and 1.20×10−6 mol L−1. Limits of detection and quantification were found to be 1.5×10−7 and 5.0×10−7 mol L−1, respectively. Up to 70 samples per hour can be analysed with a good precision (R.S.D. = 2.5%). The proposed method was successfully applied to the determination of sertraline in a commercial product. In the voltammetric determination of sertraline in flow, a high sample rate is obtained at reduced costs, opening the possibility to compete with the chromatographic methods generally used for this analysis

Caustics, catastrophes, and symmetries in curved beams

In this paper, a meaningful classification of optical caustic beams in two dimensions is presented. It is demonstrated that the phase symmetry of the beam's angular spectrum governs the optical catastrophe, which describes the wave properties of ray singularities, for cusp (symmetric phase) and fold (antisymmetric phase) caustics. In contrast to the established idea, the caustic classification arises from the phase symmetry rather than from the phase power, thus breaking the commonly accepted concept that fold and cusp caustics are related to the Airy and Pearcey functions, respectively. Nevertheless, the role played by the spectral phase power is to control the degree of caustic curvature. These findings provide straightforward engineering of caustic beams by addressing the spectral phase into a spatial light modulator or glass plate.Centro de Investigaciones Óptica

As relações entre percepção de ameaça, ansiedade, raiva e agressividade no desporto: um estudo comparativo em modalidades de contacto

Com o presente estudo pretendeu-se compreender e analisar, em modalidades desportivas com diferentes níveis de contacto físico, as relações entre a percepção de ameaça subjacente à experiência de stress e duas emoções “tonalizadas” negativamente: a ansiedade e a raiva. Os 121 atletas de ambos os sexos que participaram na investigação, com idades compreendidas entre os 14 e os 32 anos distribuíam-se por três modalidades distintas: auto-defesa (N=35), “kickboxing” (N=39) e futebol (N=47). Foram administradas as seguintes medidas psicológicas (versões traduzidas e/ou adaptadas): a) Escala de Avaliação Cognitiva da Competição Desportiva – Percepção de Ameaça (Cruz, 1996); b) Escala de Agressividade e Raiva Competitiva (Maxwell & Moores, 2007; Cruz, 2007); e c) Escala de Ansiedade Competitiva – 2 (Smith et al., 2006; Cruz & Gomes, 2007). Os resultados preliminares sugerem as boas características psicométricas dos instrumentos utilizados. Serão ainda apresentados dados correlacionais em função do sexo e modalidade e algumas implicações práticas para o estudo dos comportamentos agressivos no desporto