SAFT-γ force field for the simulation of molecular fluids: 8. hetero-group coarse-grained models of perfluoroalkylalkanes assessed with new vapour-liquid interfacial tension data

The air-liquid interfacial behaviour of linear perfluoroalkylalkanes (PFAAs) is reported through a combined experimental and computer simulation study. The surface tensions of seven liquid PFAAs (perfluorobutylethane, F4H2; perfluorobutylpentane, F4H5; perfluorobutylhexane, F4H6, perfluorobutyloctane, F4H8; perfluorohexylethane, F6H2; perfluorohexylhexane, F6H6; and perfluorohexyloctane, F6H8) are experimentally determined over a wide temperature range (276 to 350 K). The corresponding surface thermodynamic properties and the critical temperatures of the studied compounds are estimated from the temperature dependence of the surface tension. Experimental density and vapour pressure data are employed to parameterize a generic heteronuclear coarse-grained intermolecular potential of the SAFT- γ family for PFAAs. The resulting force field is used in direct molecular dynamics simulations to predict with quantitative agreement the experimental tensions and to explore the conformations of the molecules in the interfacial region revealing a preferential alignment of the PFAA molecules towards the interface and an enrichment of the perfluoro-groups at the outer interface region

Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation

Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation Pedro Duartea, Djêide Rodriguesa, Marcelo Silvaa, Pedro Morgadoa, Luís Martinsa,b and Eduardo J. M. Filipea* aCentro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal bCentro de Química de Évora, Universidade de Évora, 7000-671 Évora, Portugal Fluorinated alcohols are substances with unique properties and high technological value in the pharmaceutical and chemical industries. Trifluoroethanol (TFE), in particular, displays a number of unusual properties as a solvent. For example, it dissolves nylon at room temperature and is effectively used as solvent in bioengineering. The presence of the three fluorines atoms gives the alcohol a high ionization constant, strong hydrogen bonding capability and stability at high temperatures. In the pharmaceutical industry, TFE finds use as the major raw material for the production of inhalation anesthetics. Mixtures of TFE and water (known as Fluorinols®) are used as working fluids for Rankine cycle heat engines for terrestrial and space applications, as a result of a unique combination of physical and thermodynamic properties such as high thermal efficiency and excellent turbine expansion characteristics. Environmentally, TFE is a CFC substitute with an acceptable short lifetime and with small ozone depletion potential. Additionally, TFE is known to induce conformational changes in proteins and it is used as a co-solvent to analyze structural features of partially folded states. The (ethanol + TFE) system displays an interesting and peculiar behaviour, combining a negative azeotrope with high positive excess volumes. In this work, liquid mixtures of (ethanol + TFE) were investigated. The densities of the mixtures were measured as a function of composition between 278K and 338K and at pressures up to 700 bar. The corresponding excess volumes as a function of temperature and pressure, the isothermal compressibilities and thermal expansivities were calculated from the experimental results. The mixtures are highly non-ideal with excess volumes ranging from 0.8 - 1.0 cm3mol-1. Finally, molecular dynamic simulations were performed to model and interpret the experimental results. The Trappe force field was used to simulate the (TFE + ethanol) mixtures and calculate the corresponding excess volumes. The simulation results are able to reproduce the correct sign and order of magnitude of the experimental VE without fitting to the experimental data. Furthermore, the simulations suggest the presence of a particular type of hydrogen bridge between ethanol and TFE, that can help to rationalize the experimental results

The varying w spread spectrum effect for radio interferometric imaging

We study the impact of the spread spectrum effect in radio interferometry on the quality of image reconstruction. This spread spectrum effect will be induced by the wide field-of-view of forthcoming radio interferometric telescopes. The resulting chirp modulation improves the quality of reconstructed interferometric images by increasing the incoherence of the measurement and sparsity dictionaries. We extend previous studies of this effect to consider the more realistic setting where the chirp modulation varies for each visibility measurement made by the telescope. In these first preliminary results, we show that for this setting the quality of reconstruction improves significantly over the case without chirp modulation and achieves almost the reconstruction quality of the case of maximal, constant chirp modulation.Comment: 1 page, 1 figure, Proceedings of the Biomedical and Astronomical Signal Processing Frontiers (BASP) workshop 201

Matching of spatially homogeneous non-stationary space--times to vacuum in cylindrical symmetry

We study the matching of LRS spatially homogeneous collapsing dust space-times with non-stationary vacuum exteriors in cylindrical symmetry. Given an interior with diagonal metric we prove existence and uniqueness results for the exterior. The matched solutions contain trapped surfaces, singularities and Cauchy horizons. The solutions cannot be asymptotically flat and we present evidence that they are singular on the Cauchy horizons.Comment: LaTeX, 15 pages, 1 figure, submitted for publicatio

Optimization of the system of allocation of overdue loans in a sub-saharan Africa microfinance institution

In microfinance, with more loans, there is a high risk of increasing overdue loans by overloading the resources available to take actions on the repayment. So, three experiments were conducted to search for a distribution of the loans through the officers available to maximize the probability of recovery. Firstly, the relation between the loan and some characteristics of the officers was analyzed. The results were not that strong with F1 scores between 0 and 0.74, with a lot of variation in the scores of the good predictions. Secondly, the loan is classified as paid/unpaid based on what prediction could result of the analysis of the characteristics of the loan. The Support Vector Machine had potential to be a solution with a F1 score average of 0.625; however, when predicting the unpaid loans, it showed to be random with a score of 0.55. Finally, the experiment focused on segmentation of the overdue loans in different groups, from where it would be possible to know their prioritization. The visualization of three clusters in the data was clear through Principal Component Analysis. To reinforce this good visualization, the final silhouette score was 0.194, which reflects that is a model that can be trusted. This way, an implementation of clustering loans into three groups, and a respective prioritization scale would be the best strategy to organize and assign the loans to maximize recovery

Cinemetrics: Creative Approaches to Visualize and Analyze Movie Data

In the age of visual media that we live in, there is an immensity of content being produced worldwide every day through the cinematographic and TV industries. This, alongside with the widespread availability of Internet access and social media, has democratized the appreciation, discussion and constant analyses of movies and TV shows. Since these are visual media with their own “visual language”, where creators use a lot of visual tricks to convey information, emotion, and to show a bit of their signature style, a lot of data can be extracted from them. This represents a great potential for people trying to analyze trends and patterns in video content, for example with colour palettes, length of shots, movement in scenes, audio, etc. But all this can be overwhelming without the aid of technology, and so there has also been a growth in the development of tools based in Artificial Intelligence, and Machine and Deep Learning, to be able to quickly and efficiently analyse this data and produce meaningful and insightful results that might help in the creation of new video-based media or just for anyone interested in video, like cinematographers, video editors, animators or any others. However, with large amounts of data, the results can sometimes be hard to parse by the user, and so there’s also been a trend of trying to consolidate data into graphic representations for easier analysis, giving rise to a new field called Data Visualization. With this in mind, we attempted to develop a new tool for video analysis of multimedia files based in scripts that would be able to give information about the composition of shots and scenes, such as the instants of the cuts or estimates of numbers like the total of shots, frames and more, but also to graphically present information using multimedia data visualizations.Na era visual em que vivemos, existe uma imensidão de conteúdo a ser produzido por todo o mundo, todos os dias, através das indústrias cinematográfica e televisiva. Isto, em conjunto com a difusão do acesso à Internet e das redes sociais, democratizou a apreciação, discussão e análise de filmes e programas televisivos. Dado que estes são meios visuais com a sua própria “linguagem visual", nos quais os criadores aplicam técnicas visuais para transmitirem informação, emoção, e mesmo um pouco do seu estilo e da própria marca, existe muita informação a ser extraída e avaliada. Isto representa um grande potencial para aqueles que se dedicam a analisar tendências e padrões em conteúdos de vídeo, como por exemplo a palete de cores, duração e movimento das cenas, áudio, etc. Mas pode ser uma tarefa inviável sem a ajuda de tecnologia, e por isso existe um desenvolvimento crescente de ferramentas baseadas em Inteligência Artificial, para que seja possível analisar estes dados de forma rápida e eficiente e produzir resultados significativos e conclusivos que possam ajudar na criação de novos conteúdos de vídeo e apoiar quem esteja envolvido na criação dos mesmos, como cinematógrafos, editores de vídeo, animadores, entre outros. No entanto, esta grande quantidade de dados pode gerar resultados de difícil compreensão e interpretação para o utilizador, pelo que também existe uma tendência crescente para tentar consolidar estes dados através de representações gráficas para uma fácil análise, levando à origem do conceito de “Data Visualization”. Tendo isto em conta, tentamos desenvolver uma nova ferramenta para a análise de vídeo em ficheiros multimédia baseada em "scripts", capaz de recolher informação sobre a composições de “shots” e de cenas, como os instantes dos cortes de cena ou o número estimado de "shots", fotogramas e outros, mas, ao mesmo tempo, apresentando informação através de representações gráficas

Primary and hospitalar health care: Building a happy marriage

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsWe address the potential integration of the Hospital Dr. Fernando Fonseca E.P.E. with the Primary Care Units in its geographical coverage area in a Local Health Unit. We apply semi-structured interviews in order to understand how to best implement this model of local organization in the referred case. We classify the interviews of each unit according to pre-determined criteria and suggest measures to be implemented. Results demonstrate that the hospital is more able to promptly assume a change process towards the new organizational model when compared to the primary care units. Moreover, we reached the conclusion that the achievement of the expected benefits to the whole depends heavily on local characteristics and implementation process. There is the need to invest in key elements such as the maintenance and renewal of infrastructures and in a common information system. Albeit these investments do not assure the achievement of the benefits of an integrated management system per se, they are essential in the process of constructing an unique entity