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

VCube-PS: A Causal Broadcast Topic-based Publish/Subscribe System

In this work we present VCube-PS, a topic-based Publish/Subscribe system built on the top of a virtual hypercube-like topology. Membership information and published messages are broadcast to subscribers (members) of a topic group over dynamically built spanning trees rooted at the publisher. For a given topic, the delivery of published messages respects the causal order. VCube-PS was implemented on the PeerSim simulator, and experiments are reported including a comparison with the traditional Publish/Subscribe approach that employs a single rooted static spanning-tree for message distribution. Results confirm the efficiency of VCube-PS in terms of scalability, latency, number and size of messages.Comment: Improved text and performance evaluation. Added proof for the algorithms (Section 3.4

Credit Guarantee and the Impact in Financial Structure of the Portuguese SMEs

The aim of this work is to show the relevance of guarantees provided by the Mutual Credit Guarantee System (MCGS - the Portuguese Society of Credit Guarantee SPGM) as an instrument used in the financing of SMEs, especially in restructuring long-term debt (LTD) and bank loans. The study provides empirical evidence and puts forward an explanatory model of the influence of the mutual credit guarantees on the financing of SMEs. The results obtained show that long-term debt (LTD) financing is positively influenced by the guarantees provided by the MCGS to SMEs as it allows greater debt capacity, especially in the medium and long term, for firms that usually cannot obtain this type of financing. The results also suggest that this type of guarantees creates an environment of confidence among all stakeholders involved.info:eu-repo/semantics/publishedVersio

Soil-plant-animal transfer models to improve soil protection guidelines: a case study from Portugal

Food chain models are essential tools to assess risks of soil contamination in view of product quality including fodder crops and animal products. Here we link soil to plant transfer (SPT) models for potentially toxic elements (PTEs) including As, Ba, Cd, Co, Cu, Hg, Ni, Pb, Sb, U and Zn with models describing accumulation in animal organs. Current EU standards for food products and acceptable daily intake levels (ADI) for humans were used as critical limits. The combined model is used to assess the impact of soil contamination on animal health, product quality and human health using data from 100 arable fields. Results indicate that 42 existing arable fields near industrial and mining sites are unsuitable for animal grazing in view of food safety due to elevated intake of Cd, Cu, Hg and Pb by cows and sheep. At 10 sites daily intake levels of As by cows exceeded threshold concentrations regarding the quality of animal products. The food chain model also was used inversely to derive soil threshold concentrations in view of EU fodder standards. Calculated threshold levels in soil for As, Cd, Cu, Pb, Hg and Zn appear to be in line with those proposed or used in other EU countries. As such the approach applied here can form a conceptual basis for a more harmonized risk assessment strategy regarding the protection of animal and human health.publishe

Herbivory drives kelp recruits into ‘hiding’ in a warm ocean climate

Assessing effects of herbivory across broad gradients of varying ocean climate conditions and over small spatial scales is crucial for understand- ing its influence on primary producers. Effects of her- bivory on the distribution and abundance of kelp re- cruits were examined experimentally at two regions under contrasting ocean climate. Specifically, the abundance and survivorship of kelp recruits and the abundance of macro-herbivores were compared be- tween a ‘cool’ and a ‘warm’ region in northern and central Portugal, respectively. In each region, the abundance of kelp recruits and the intensity of grazing were compared between habitats of different topography within reefs (open reef vs. crevices). Com- pared to the ‘warm’ region, the abundance of kelp re- cruits was 3.9 times greater in the ‘cool’ region, where 85% of recruits were found in open reef habitats. In contrast, 87% of recruits in the ‘warm’ region were re- stricted to crevices. The ‘warm’ region had 140 times greater abundances of sea urchins, 45 times more herbivorous fish and 4.1 times more grazing marks on kelp recruits than the ‘cool’ region. Grazing assays showed ca. 50 times higher rates of kelp biomass con- sumption, mainly by fishes, and zero survivorship of kelp recruits in the ‘warm’ relative to the ‘cool’ region. This study suggests both temperature and herbivores affect abundances of kelp recruits across latitudes, and demonstrates how herbivores affect their distri- bution at local scales, driving kelp recruits into ‘hiding’ in crevices under intense herbivory. Conse- quently, where net recruitment success is compro- mised by herbivory, the persistence of kelps will be contingent on availability of topographical refuges

DC-DC power converter for high power solar photovoltaic system

Worldwide there is an enormous dependence on fossil fuels to produce electricity. Burning fossil fuels results in CO2 emission into the atmosphere, causing a negative environmental impact. In order to mitigate these problems, there is a need to integrate renewable energy sources into the power grid, namely solar photovoltaic (PV) energy. Power electronics converter solutions for solar PV module interface are vast and have advantages and disadvantages depending on the purpose. In addition, when the purpose is efficiency, it is important to consider the choice of the most appropriate power semiconductors. This paper presents a study, sizing, and development of a DC-DC power converter for high-power solar PV applications. In this study, a DC-DC boost interleaved power converter with two arms controlled by an incremental conductance Maximum Power Point Tracking (MPPT) control algorithm is proposed. The MPPT is combined with a Proportional-Integral (PI) controller for individual control of the current on each arm and was applied to extract the maximum power available at the solar PV module for different solar radiation and temperature conditions. The digital control system was implemented in a TMS320F28335 microcontroller from Texas Instruments.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the MEGASOLAR Project POCI-01-0247-FEDER-047220. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT foundation

Avaliando a Satisfação e Frustração das Necessidades em Português Instrutores de Exercício: validade da escala, fiabilidade e invariância entre géneros

Objective: The aim of the present study was to validate the Basic Psychological Need Satisfaction and Frustration Scale in Exercise for fitness instructors. Methods: Data from 477 exercise professionals (319 males, 158 females) was collected. Results: CFA supported the adapted and validated six-factor model: [χ2(237) = 1096.796, χ2/df= 4.63; B-S p < .001, CFI = .930, TLI = .918, SRMR= .0366, RMSEA = .079 (CI90% = .069, .089)], assessing satisfaction and frustration of basic psychological needs in Portuguese exercise professionals. Moreover, the analysis revealed acceptable composite reliability, and construct validity of the adapted version. Results revealed nomological validity, as well as invariance between male and female. No differences were found across latent means, and magnitude effects were trivial between gender. Conclusion: These results support the use of the adapted scale in exercise professionals, showing measurement invariance between gender. This scale is able to measure how exercise professionals experience satisfaction and frustration of basic needs when prescribing exercise to individuals in fitness context.Objetivo: El objetivo del presente estudio fue validar la Escala de Satisfacción y Frustración de Necesidades Psicológicas Básicas en el Ejercicio para instructores de ejercicio físico. Métodos: Se recopilaron datos de 477 profesionales del ejercicio (319 hombres, 158 mujeres). Resultados: CFA apoyó el modelo de seis factores adaptado y validado: [χ2 (237) = 1096.796, χ2 / df = 4.63; B-S p <.001, CFI = .930, TLI = .918, SRMR = .0366, RMSEA = .079 (CI90% = .069, .089)], evaluando la satisfacción y la frustración de las necesidades psicológicas básicas en los profesionales del ejercicio portugués. Además, el análisis reveló una validez en la confiabilidad compuesta, constructo y nomológica aceptables de la versión adaptada, así como invariabilidad entre hombres y mujeres. No se encontraron diferencias entre las medias latentes, y los efectos de magnitud fueron triviales entre los géneros. Conclusión: estos resultados apoyan el uso de la escala adaptada en los profesionales del ejercicio, que muestran la invariancia de la medición entre los géneros. Esta escala es capaz de medir cómo los profesionales del ejercicio experimentan la satisfacción y la frustración de las necesidades básicas, y cómo regulan los comportamientos interpersonales.Objetivo: O objetivo deste estudo consistiu na validação do Basic Psychological Need Satisfaction and Frustration Scale in Exercise em instrutores de fitness. Métodos: Recolhemos dados de 477 profissionais de exercício físico (319 masculino, 158 feminino). Resultados: A análise CFA suporta o modelo de 6-factores adaptado e validado: [χ2(237) = 1096.796, χ2/df= 4.63; B-S p < .001, CFI = .930, TLI = .918, SRMR= .0366, RMSEA = .079 (CI90% = .069, .089)], avaliando a satisfação e frustração das necessidades psicológicas básicas em instrutores profissionais portugueses de exercício físico. Além disso, a análise revela fiabilidade compósita aceitável e validade dos construtos da versão adaptada. Os resultados revelam validade nomológica, bem como invariância entre sexo masculino e feminino. Não foram encontradas diferenças entre as médias latentes, e a magnitude dos efeitos foi trivial entre géneros. Conclusão: Estes resultados suportam o uso desta escala adaptada em profissionais do exercício físico, mostrando ser invariante entre géneros. Esta escala é capaz de medir como os técnicos profissionais de exercício físico experienciam a satisfação e frustração das necessidades básicas aquando da prescrição de exercício físico para clientes de exercício no contexto do fitnessinfo:eu-repo/semantics/publishedVersio

Evaluation of Lower Limb Arteriovenous Diameters in Indoor Soccer Athletes: Arterial Doppler Ultrasound Study

The purpose of this study was to analyze the arterial and venous diameters of lower limbs in indoor soccer athletes and non-athletes using Doppler ultrasound to identify the differences in the variation of arterial and venous diameters between groups. Additionally, we intended to verify the differences of arterial and venous diameters between the skilled member (right member) and the not skilled member in each group. 74 male volunteers, aged between 19 and 30 years old, were divided in a group of athletes (n = 37, 24 ± 2.7 years, soccer players from national championship), and a group of non-athletes (n = 37, 26 ± 2.83 years). Vascular lower limb was assessed using Doppler ultrasound (Philips HD7 echograph with linear transducer 7–12 MHz). The athletes showed higher diameters of right common femoral artery (p = 0.009; moderate), left common femoral artery (p = 0.005; moderate), right deep femoral artery (p = 0.013; moderate), right popliteal artery (p = 0.003; moderate), and left popliteal artery (p = 0.017; small) than non-athletes. Veins’ diameters were also higher in athletes, specifically the right deep femoral vein (p ≤ 0.001; large), left deep femoral vein (p ≤ 0.001; large), right popliteal vein (p ≤ 0.001; large), and left popliteal vein (p ≤ 0.001; large). Differences were found between the skilled and non-skilled leg in athletes in the popliteal vein (7.68 ± 1.44 mm vs. 7.22 ± 1.09 mm, respectively, p < 0.003). It seems that futsal athletes have superior mean diameters of lower limbs arteries and veins of the deep venous system to non-athletes. Moreover, the veins presented greater dilation, namely of the leg of the skilled lower limb.info:eu-repo/semantics/publishedVersio