Exploring the dynamics of the Kelvin-Helmoltz instability in paraxial fluids of light

Paraxial fluids of light have recently emerged as promising analogue physical simulators of quantum fluids using laser propagation inside nonlinear optical media. In particular, recent works have explored the versatility of such systems for the observation of two-dimensional quantum-like turbulence regimes, dominated by quantized vortex formation and interaction that results in distinctive kinetic energy power laws and inverse energy cascades. In this manuscript, we explore a regime analogue to Kelvin-Helmoltz instability to look into further detail the qualitative dynamics involved in the transition from smooth laminar flow to turbulence at the interface of two fluids with distinct velocities. Both numerical and experimental results reveal the formation of a vortex sheet as expected, with a quantized number of vortices determined by initial conditions. Using an effective length transformation scale we get a deeper insight into the vortex formation phase, observing the appearance of characteristic power-laws in the incompressible kinetic energy spectrum that are related to the single vortex structures. The results enclosed demonstrate the versatility of paraxial fluids of light and may set the stage for the future observation of distinct classes of phenomena recently predicted to occur in these systems, such as radiant instability and superradiance

An industrial brewer’s yeast strain in very high gravity wort fermentations

In the beer production, the fermentation of worts whose gravity is higher than 18 ºP has been presented as an efficient way to improve the capacity of brewery facility without changes in the brewhouse. In this work, a brewer yeast strain was submitted to high gravity fermentations to evaluate the influence and the limits of the environmental parameters on the fermentation performance and final product profile. The variables included in this study were the primary fermentation temperature, wort concentration (extract) and yeast pitching rate. Static fermentations were carried out anaerobically in 2 L tall tubes (EBC recommendation for small scale brewing fermentations) with 15, 18 and 22 ºP wort, at constant temperature of 12, 15 and 18 ºC. The yeast was grown aerobically at 27 ºC in 15 ºP wort (saturated with air) and collect by filtration to inoculate by mass at different pitching rates of 12, 18 and 22 million cells/ml. Fermentations were monitored daily measuring the ethanol, extract, pH, temperature, biomass in suspension and viability. At the end of the primary fermentation, the green beer was analysed concerning diacetil, esters and high alcohols by gas chromatography. Fermentation data were statistically treated in order to obtain an optimum approach for the studied parameters. For statistical proposes, the fermentation performance was measured by ethanol produced, apparent extract and the fermentation time. Although the temperature has a positive effect on the indicators of the fermentation performance, the wort concentration has not a positive effect for all indicators. When the wort has higher concentration at the beginning of the fermentation, as expected, the fermentation takes longer to be finished with more ethanol produced. Considering that the produced ethanol, the fermentation time and the residual extract have the same level of interest for the brewing process, the statistical analysis showed that the optimal point for the wort concentration, fermentation temperature and pitching rate is 20 ºP, 18 ºC and 20x106 cell/ml, respectively. The optimal conditions were repeated and the beer profile regarding the aroma profile was determined

Structural behaviour analysis of Faria Guimarães station

No presente estudo efectua-se a modelação e análise do comportamento estrutural da estação Faria Guimarães, do Metro do Porto. A estação é constituída por um cruzamento oblíquo de duas grandes galerias executadas através do método SEM/NATM. A obra é de elevada complexidade devido aos condicionamentos geométricos da estação e obras adjacentes, à grande heterogeneidade do maciço e à ocupação intensa da superfície. A análise do comportamento estrutural da estação foi realizada recorrendo a modelos numéricos 2D e 3D, bem como a resultados obtidos com a observação da estação.In present paper the modelling and structural behaviour analysis of the Faria Guimarães station, of Metro do Porto, is presented. The station includes the inclined intersection of two large galleries executed through SEM/NATM method. The work is highly complex due to geometric limitations of the station and adjacent works, the heterogeneity of the rock mass and the dense occupation at surface. The structural behaviour analysis of the station was performed using 2D and 3D numerical models, as well as results obtained through the observation of the station.Fundação para a Ciência e Tecnologia (FCT) - Projecto POCI/ECM/57495/2004, intitulado Geotechnical Risk in Tunnels for High Speed Trains

Incorporation of industrial wastes in wood pellets

ABSTRACT: The present work evaluates the incorporation of industrial wastes (Refuse Derived Fuel-RDF) into biomass for pellet production. Its influence on parameters such as pellet production, combustion and gas emissions was studied for up to 10% of residues incorporation. This approach also deals with the diverting of industrial waste from landfills. The main objectives were: increasing the heat value of the final product, diverting industrial residues with energy potential from landfill and assess the quality of different types of pellets with incorporation of industrial residues. Its implementation was carried out in three phases: selection and characterization of the different industrial residues, production of pellets from different mixtures of wastes and combustion tests. For this purpose a comprehensive characterization of the pellets, the gaseous emissions during combustion and the chemical characterization of the resulting ashes was carried out. The study has shown that the application of industrial residues is a promising route for their incorporation in pellets which should be balanced by the reduction of wastes for landfill. However a few problems were identified: higher difficulty in pelletizing and likely excessive wear of the pellet mill for some of the residues; combustion equipment requiring air supply adjustment and higher ash contents

A diversificação das receitas bancárias: seu impacto sobre o risco e o retorno dos bancos brasileiros

O objetivo deste estudo é determinar o impacto da diversificação das receitas bancárias sobre o risco e o retorno dos bancos brasileiros. Essa estratégia foi adotada por bancos em diversos países, inclusive no Brasil. Em 2003, as receitas noninterest (não decorrentes de juros) representavam 17,80% da receita operacional dos bancos analisados e, em 2014, essa participação havia aumentado para 27,40%. Embora muitos estudos tenham abordado a questão para bancos americanos, europeus e asiáticos, este tema ainda não foi abordado para uma amostra de bancos brasileiros. Como o setor bancário é uma variável crucial à estabilidade do sistema financeiro, é importante estudar os fatores que afetam o risco e o retorno dos bancos. Analisamos a amostra para o período entre 2003 e 2014, utilizando dados em painel dinâmico através do Método Generalizado dos Momentos para abordar questões de endogeneidade, heterocedasticidade e autocorrelação. Nossos principais resultados mostram que as receitas noninterest possuem um papel importante no desempenho dos bancos estudados; nossa análise das atividades de intermediação financeira mostrou que as operações de crédito produziram melhores resultados do que as atividades de negociação de títulos. Além disso, confirmando as hipóteses propostas, as receitas noninterest apresentaram, de maneira geral, um impacto positivo sobre o retorno e o retorno ajustado ao risco nos bancos estudados. Entretanto, ao contrário do que esperávamos, as receitas noninterest mostraram uma relação positiva com o risco desses bancos (embora estatisticamente não significativa). É importante destacar as variáveis de controle, ou seja, a taxa de juros real, o PIB e o crescimento bancário, as quais foram relevantes para a determinação do desempenho dos bancos.The present study aims to determine the impact of bank revenue diversification on Brazilian banks’ risk and return. This strategy has been adopted by banks in several countries, including Brazil. In 2003, noninterest income accounted for 17.80% of the operating revenue of the banks analyzed, and in 2014, this share increased to 27.40%. While many studies have addressed the subject in American, European and Asian banks, it still has not been approached in a sample of Brazilian banks. Since the banking industry is a key variable for the financial system’s stability, it is important to study the factors that affect banks’ risk and return. We analyzed the sample for the period from 2003 to 2014, using dynamic panel data GMM (Generalized Method of Moments) to address endogeneity, heteroscedasticity and autocorrelation problems. Our main results show that noninterest income has a major role in the performance of the banks studied; our analysis of financial intermediation activities showed that loan operations produced better results than trading. Moreover, confirming the hypotheses proposed, noninterest income showed a generally positive impact on return and risk adjusted return for the banks studied. However, against our expectation, noninterest income showed a positive relationship with the risk of these banks (although not statistically significant). It is worth highlighting the control variables, i.e., real interest rate, GDP and bank growth, which were relevant in determining bank performance

Tipos habitacionais e estratégias de reabilitação do núcleo urbano antigo do Seixal

Os núcleos urbanos antigos são portadores de um património histórico e arquitectónico a proteger e a potenciar. Para tal, é necessário compreender a sua génese, tanto no plano do edifício como no plano do conjunto urbano. Deste modo, considera-se importante o estudo do edificado como apoio a intervenções de reabilitação qualificadas, conscientes e sustentáveis. Este artigo aborda o assunto dos núcleos urbanos antigos na perspectiva da análise e inventariação das características do edificado. O processo de tipificação apresenta-se como síntese das principais formas de construção presentes, baseado na inspecção (observação e levantamento) e registo, tomando como caso de estudo o Núcleo Urbano Antigo do Seixal

Single-neuron axonal reconstruction: The search for a wiring diagram of the brain

Reconstruction of the axonal projection patterns of single neurons has been an important tool for understanding both the diversity of cell types in the brain and the logic of information flow between brain regions. Innovative approaches now enable the complete reconstruction of axonal projection patterns of individual neurons with vastly increased throughput. Here, we review how advances in genetic, imaging, and computational techniques have been exploited for axonal reconstruction. We also discuss how new innovations could enable the integration of genetic and physiological information with axonal morphology for producing a census of cell types in the mammalian brain at scale.Reconstruction of the axonal projection patterns of single neurons has been an important tool for understanding both the diversity of cell types in the brain and the logic of information flow between brain regions. Innovative approaches now enable the complete reconstruction of axonal projection patterns of individual neurons with vastly increased throughput. Here, we review how advances in genetic, imaging, and computational techniques have been exploited for axonal reconstruction. We also discuss how new innovations could enable the integration of genetic and physiological information with axonal morphology for producing a census of cell types in the mammalian brain at scale.First author draf

Architectonic and constructive characterisation of the old urban centre of Seixal, Portugal

This paper addresses the issue of the old urban centres from the perspective of the analysis and inventory of building features. The cataloguing process of the building typologies is presented herein as a synthesis of the main construction forms, with the old city centre of Seixal being used as a case study. Furthermore, and taking into account the relation between such two dimensions, a material and constructive characterisation of the buildings in the old urban centre of Seixal is presented. As marks of an historical and architectural heritage, old urban centres should be protected, safeguarded and potentiated. For such, it is fundamental to have a complete understanding of the genesis of both buildings and urban mesh. This fact is essential to the support of qualified, conscientious and sustainable rehabilitation interventions on the old building stock

Experimental characterization of the out-of-plane performance of regular stone masonry walls, including test setups and axial load influence

Stone masonry is one of the oldest and most worldwide used building techniques. Nevertheless, the structural response of masonry structures is complex and the effective knowledge about their mechanical behaviour is still limited. This fact is particularly notorious when dealing with the description of their out-of-plane behaviour under horizontal loadings, as is the case of the earthquake action. In this context, this paper describes an experimental program, conducted in laboratory environment, aiming at characterizing the out-of-plane behaviour of traditional unreinforced stone masonry walls. In the scope of this campaign, six full-scale sacco stone masonry specimens were fully characterised regarding their most important mechanic, geometric and dynamic features and were tested resorting to two different loading techniques under three distinct vertical pre-compression states; three of the specimens were subjected to an out-of-plane surface load by means of a system of airbags and the remaining were subjected to an out-of-plane horizontal line-load at the top. From the experiments it was possible to observe that both test setups were able to globally mobilize the out-of-plane response of the walls, which presented substantial displacement capacity, with ratios of ultimate displacement to the wall thickness ranging between 26 and 45 %, as well as good energy dissipation capacity. Finally, very interesting results were also obtained from a simple analytical model used herein to compute a set of experimental-based ratios, namely between the maximum stability displacement and the wall thickness for which a mean value of about 60 % was found