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

Implicações da autonomia na gestão da aprendizagem em ambiente virtual

The concept of autonomy presented by several authors regards proactivity of learners to access, browse, search content, meet the demands of the teachers. Our question is: is it enough to understand that this or that learner is autonomous? To deepen this debate we asked 10 teachers who worke in na online postgraduate course graduate to appoint elements in order to identify the level of autonomy of learners in learning process. With the responses analysis, it is understood that autonomy cannot be considered purely instrumental and should be part of training strategies.O conceito de autonomia apresentado por diversos autores diz respeito á proatividade dos aprendentes para acessar, navegar, buscar os conteúdos, responder as demandas dos professores. Nossa pergunta é: isso é suficiente para entender que este ou aquele aprendente é autônomo? Para aprofundar esse debate fizemos solicitamos a 10 professores que atuaram em um curso de pós-graduação online o que eles elencariam para identificar o grau de autonomia dos aprendentes em relação ao processo de aprendizagem. A partir da analise das respostas, propomos que a autonomia não pode ser considerada apenas instrumental e que deve fazer parte das estratégias formativa.info:eu-repo/semantics/publishedVersio

Narratives of dependence in online learning networks: the way teachers use learning networks service to promote autonomy

Neste artigo analisa-se a instituição de redes de aprendizagens em ambiente virtual e a necessidade de estabelecer a dialogia como estratégia metodológica. Entende-se que a ação dialógica ocorra quando cada sujeito possa agir e/ou construir sua autonomia viabilizando sua construção nas redes de aprendizagem. Para a base empírica deste estudo, analisamos 1327 mensagens de 5 professores em fóruns para orientação do trabalho de conclusão de um curso online com 200 alunos, distribuídos em 5 turmas. Esta pesquisa permite-nos concluir que prevalece o perfil centralizador dos professores, comum na Educação tradicional, mesmo sendo professores experientes em Educação mediada pelas Tecnologias Digitais de Informação e Comunicação (TDIC) e com formação em Educação. O que confirma a necessidade de se investir na formação de professores para a docência online, a fim de superar essa postura tradicional para que a estratégia metodológica colaborativa e interativa das redes de aprendizagem possa ser implementada.In this article is analyzed the learning network institutions in virtual environment and the need to establish the dialogic as a methodological strategy. It is understood that the dialogic action where each individual can act and/or build its autonomy enables with the construction of learning networks. For the empirical basis of this study we analyzed 1327 posts of 5 teachers in forums for research orientation of 5 classes of an online course with 200 students enrolled. This study allows us to conclude that prevails the centralizer profile of teachers, common in traditional education, even when the teachers are already experienced on education mediated by digital technologies and masters education. This confirms the need to invest in training teachers for online teaching, in order to overcome the traditional approach and for the collaborative and interactive methodological strategy of learning networks can be implemented.info:eu-repo/semantics/publishedVersio

Relationship between buyer and supplier in outsourcing of information technology services

Companies rely on others to achieve its goals. This is not only true in terms of management of the flows of information and materials through the supply chain but also in terms of performing specific processes and sub-processes intimately related to the company’s operation. IT Outsourcing (ITO) is increasing worldwide and the relational governance impacts the outsourcing outcomes (Lacity et al, 2016). This perspective is usually visited for the buyer and supplier perspectives using decision makers and leaving a gap in literature in terms of the perspective of the consultants. This paper aims at analysing, in ITO, how the development of the relationship between buyer and supplier strengthens supplier performance over time, from the perspective of the consultants. A survey to IT consultants was applied and then a multilevel analysis was performed, taking account for the aggregate values of the variables characterizing buyer supplier relationships based on Johnston and Staughton (2009), Krause et al. (2007) and Blonska et al. (2013). Findings show that strategic relationships are associated with higher supplier investment in relational management. In this type of relationship higher levels of trust are linked to an attribution of more recognised benefits from the relationship, and reciprocal investment to the buyer. Furthermore, an improvement of the dedication in the relation and an improved service performance were attributed by IT consultants to the supplier.info:eu-repo/semantics/publishedVersio

Effective fractionation of microalgae biomass as an initial step for its utilization as a bioenergy feedstock

Scenedesmus obliquus, a biotechnologically relevant microalgae, was grown in 70 L vertical photobioreactors using non-supplemented secondary brewery wastewater as a culture medium. Upon collection, by mechanical means, the cells were subjected to hydrothermal (autohydrolysis) and dilute acid hydrolysis (0.5 % sulfuric acid) pre-treatments carried out using pressure micro-reactors under isothermal conditions up to 300 min. Both processes enabled a high recovery of soluble sugars (~50 %) that were, in a great majority, present in the added-value oligomeric form (92 % and 90.5 % for autohydrolysis and dilute acid hydrolysis, respectively). Protein solubilization also presented relevant yields (35 % removal), with dilute acid hydrolysis allowing both higher oligosaccharides and protein productivities at a milder temperature. As compared to the current whole microalgae biomass-based upgrade strategies, the use of these mild processes is extremely promising, as they will enable the future co-production of added-value oligosaccharides, and protein, which can be relevant co-products of a biofuels-based biorefineryinfo:eu-repo/semantics/publishedVersio

Real-life comparison between diesel and electric car energy consumption

Vehicle electrification is one of the strategies with higher potential for increasing the efficiency of vehicle powertrains, reducing the dependency on dwindling fossil fuel sources and meeting stringent emissions targets set by policy makers. Despite all the theoretical assessments and manufacturer’s claimed efficiency and emissions records of current vehicles, there is a lack of data concerning real life comparisons of Electric Vehicles (EV) against Internal Combustion Engine (ICE) cars. A test program comparing the energy consumption of an EV and a diesel powered (ICE) car was carried out. Both short (at levelled ground and 6% up hill) and long distance tests were performed for several fixed vehicle speeds. Measurements enabling the assessment of average energy consumption, required power and energy suplied were performed for both vehicles. Results indicate that in terms of vehicle use (Tank to Wheel perspective) the electric powertrain is significantly more energy efficient than the Diesel powertrain, although the difference between the two is less pronounced for higher power events.Fundação para a Ciência e a Tecnologia (FCT) - Project MOBI-MPP (MIT-Pt/EDAM-SMS/0030/2008), SFRH/BPD/51048/2010, SFRH/BPD/89553/2012MIT Portugal Program (EDAM), MOBI-MPP ProjectFEDER - Programa Operacional Factores de Competitividade COMPET

A case study on the conversion of an internal combustion engine vehicle into an electric vehicle

This paper presents the conversion process of a traditional Internal Combustion Engine vehicle into an Electric Vehicle. The main constitutive elements of the Electric Vehicle are presented. The developed powertrain uses a three-phase inverter with Field Oriented Control and space vector modulation. The developed on-board batteries charging system can operate in Grid-to-Vehicle and Vehicle-to-Grid modes. The implemented prototypes were tested, and experimental results are presented. The assembly of these prototypes in the vehicle was made in accordance with the Portuguese legislation about vehicles conversion, and the main adopted solutions are presented.FCT – Fundação para a Ciência e Tecnologia in the scope of the project: PEst - OE/EEI/UI0319/201

Efeito da germinação a baixas temperaturas sobre o vigor de sementes de feijão comum.

O presente trabalho teve como objetivo estimar o efeito do frio sobre o vigor de sementes de feijão comum

Digital control of a novel single-phase three-port bidirectional converter to interface renewables and electric vehicles with the power grid

This paper presents the digital control of a novel single-phase three-port bidirectional (STB) converter used to interface renewables from solar photovoltaic (PV) panels and electric vehicles (EVs) with the power grid. Using an appropriated power theory, the STB converter can be used to exchange ener-gy between the PVs, the EVs and the power grid in four distinct modes: (1) The EV receives energy from the power grid (G2V - grid-to-vehicle operation mode) or delivers energy to the power grid (V2G - vehicle-to-grid operation mode); (2) All the energy produced by the PV panels is delivery to the power grid; (3) All the energy produced by the PV panels is delivery to the EV; (4) The EV can receive energy simultaneously from the PV panels and from the power grid (G2V). The currents of the power grid, PV panels and EV are con-trolled through independent predictive current control strategies, which ensure good power quality levels. This paper presents the architecture of the proposed STB converter and the detailed explanation of the digital implementation of the control algorithms, namely, the power theory and the predictive current control strategies. The control algorithms were validated through computational simula-tions and experimental results.Fundação para a Ciência e Tecnologia (FCT); FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER- 006941

Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6

Background <br/> The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene. <br/> Results Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East. <br/> Conclusions <br/> A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast