856 research outputs found

    Real-life comparison between diesel and electric car energy consumption

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    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 comprehensive comparison of voltage and current control techniques for three-phase VSI converters

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    Converting electrical energy from direct current to alternate current, or vice versa, is one of the most frequently performed tasks in today’s electrical systems. The Voltage Source Inverter (VSI) is the most widely used topology to accomplish this task. This paper compares the performance of three control algorithms for voltage source inverter (VSI) with PI, PR and MP control algorithms were applied for voltage control and current control. For voltage control the VSI synthesizes the sinusoidal voltage system for an islanded application. In current control the VSI injects energy into the power grid by synthesizing sinusoidal currents. A general comparison is made of the performance of the three control algorithms under the presented conditions, helping to choose the control algorithm to use in a given application.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT foundation

    Integration of Single Cell Traps, Chemical Gradient Generator and Photosensors in a Microfluidic Platform for the Study of Alpha-Synuclein Toxicity in Yeast

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    AbstractAlpha-synuclein (aSyn) is a key player in Parkinson's disease. Genetically engineered yeast cells producing aSyn fused with GFP (aSyn-GFP) have been used to study this protein. In this work, we present a microfluidic platform with integrated photosensors that captures single yeast cells in arrays of hydrodynamic traps and exposes them to a chemical gradient of precise composition. This platform enables the study of the effects of aSyn expression level and aggregation in genetically modified yeast cells by chemical stimulation. The photosensors allow the detection of cells in the traps by measuring the variations in light transmission or of the fluorescence produced by aSyn-GFP for real-time signal acquisition

    Eco-friendly methods for extraction and modification of cellulose: an overview

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    Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose’s use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed.BDE 05|POCI-01-0247-FEDER021874; 2022.07519.PTDCinfo:eu-repo/semantics/publishedVersio

    Transcriptome analysis of Loxosceles laeta (Araneae, Sicariidae) spider venomous gland using expressed sequence tags

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    <p>Abstract</p> <p>Background</p> <p>The bite of spiders belonging to the genus <it>Loxosceles </it>can induce a variety of clinical symptoms, including dermonecrosis, thrombosis, vascular leakage, haemolysis, and persistent inflammation. In order to examine the transcripts expressed in venom gland of <it>Loxosceles laeta </it>spider and to unveil the potential of its products on cellular structure and functional aspects, we generated 3,008 expressed sequence tags (ESTs) from a cDNA library.</p> <p>Results</p> <p>All ESTs were clustered into 1,357 clusters, of which 16.4% of the total ESTs belong to recognized toxin-coding sequences, being the Sphingomyelinases D the most abundant transcript; 14.5% include "possible toxins", whose transcripts correspond to metalloproteinases, serinoproteinases, hyaluronidases, lipases, C-lectins, cystein peptidases and inhibitors. Thirty three percent of the ESTs are similar to cellular transcripts, being the major part represented by molecules involved in gene and protein expression, reflecting the specialization of this tissue for protein synthesis. In addition, a considerable number of sequences, 25%, has no significant similarity to any known sequence.</p> <p>Conclusion</p> <p>This study provides a first global view of the gene expression scenario of the venom gland of <it>L. laeta </it>described so far, indicating the molecular bases of its venom composition.</p

    Estudo da partição de fitase produzida por Aspergillus niger var. phoenicis utilizando bioconversão extrativa em sistemas de duas fases aquosas PEG/citrato

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    Existem diversos métodos tradicionais que são utilizados para extratir biomoléculas produzidas por fermentação convencional. Um método alternativo é o sistema de duas fases aquosas, o qual foi desenvolvido para a extração de bioprodutos. A bioconversão extrativa trata-se de um sistema de duas fases aquosas que integra cultivo microbiológico à produção e recuperação do bioproduto. Fitases são fosfatases específicas que estão envolvidas na catálise do ácido fitico. O objetivo deste trabalho foi estudar a partição da fitase produzida por A. niger var. phoenicis por bioconversão extrativa utilizando PEG/citrato. Realizou-se um planejamento fatorial completo 25, estudando as seguintes variáveis: massa molar do PEG, concentração do PEG, concentração de citrato, pH e agitação, onde obteve-se como variável-resposta o coeficiente de partição em atividade (KATIV). Neste trabalho conseguiu-se um coeficiente de partição de 25,77 utilizando MPEG (8000 g/mol), CPEG, (26,0% m/m), CCIT (20,0% m/m), pH (6,0) e agitação (100 rpm). Através dos resultados obtivos, pode-se concluir que a fitase utilizada no presente estudo apresenta uma tendência de particionar para a fase superior do sistema (K>1). A técnica de fermentação extrativa utilizando SDFA PEG/citrato demonstrou ser promissora para extração de fitase produzida por A. niger var. phoenicis, podendo ser aplicada na composição de rações comerciais

    Influence of composition, bonding characteristics and microstructure on the electrochemical and optical stability of AlOxNy thin films

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    Thin films of AlOxNy were deposited by magnetron sputtering in a wide composition range. Different structures and morphologies were observed, depending on the composition and bonding states, which opened the possibility to tailor the properties of this oxynitride system between those of pure Al and those of nitride and oxide films. In a wide range of stoichiometries, one can report the formation of nanocomposite porous films, where Al nanoparticles are dispersed in an amorphous matrix of AlOxNy. The electrochemical behaviour of the films was studied in isotonic NaCl solution. It was observed that the pitting 2 potential characteristic of aluminium disappears with the incorporation of oxygen and nitrogen in the films, being replaced by a smooth current increase. Electrochemical impedance spectroscopy performed during 35 days showed that the corrosion resistance of the films steadily increases. The unusual optical reflectance profile of some films is maintained after immersion for several months.Fundação para a Ciência e a TecnologiaPrograma Pessoa 2010/2011, Cooperação Portugal/França, Proc.º 441.00, Project“COLOURCLUSTER”

    Nanocellulose toxicity in vitro models: contributing to its safety assessment to human health

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    As nanoceluloses são nanomateriais inovadores com potencial para uma vasta gama de aplicações industriais e biomédicas. No entanto, a expansão da sua produção tem vindo a suscitar preocupações quanto aos possíveis efeitos, a longo prazo, na saúde humana. Este estudo teve como objetivo avaliar a segurança de algumas nanoceluloses produzidas a partir de matéria-prima nacional, através da caracterização da sua potencial toxicidade em células de mamífero. Para tal, testaram-se duas celuloses nano /microfibrilares (CNF e CMF ) e uma celulose nanocristalina (CNC). Analisou-se a citotoxicidade usando ensaios colorimétricos e o ensaio clonogénico, e a genotoxicidade pelo ensaio do micronúcleo in vitro em células pulmonares de mamífero (A549 e V79 ) e em osteoblastos humanos ( MG-63 ). A indução de espécies reativas de oxigénio (ROS) e a internalização celular foram também estudadas nas células A549. Observou- -se citotoxicidade no ensaio clonogénico, principalmente no caso da CNC, mas não nos restantes ensaios, não havendo também indução de ROS. Todas as nanoceluloses revelaram efeitos genotóxicos nalgumas concentrações, uma vez que induziram micronúcleos e /ou pontes nucleoplásmicas num dos modelos celulares. Para além disso, visualizou-se a internalização da CNF e CMF, mas não da CNC, em células A549. Esta primeira avaliação toxicológica veio contribuir para prevenir a exposição a materiais celulósicos potencialmente perigosos, procurando impulsionar o desenvolvimento de materiais inovadores e mais seguros.Nanocelluloses are innovative nanomaterials with potential for a wide range of industrial and biomedical applications. However, the expansion of its production has raised concerns about their possible long-term effects on human health. This study aimed to evaluate the safety of various nanocelluloses through the characterization of their potential toxicity in mammalian cells. Two samples of nano/microfibrillar celluloses with different pre-treatments (CNF and CMF) and a nanocrystalline cellulose (CNC) were tested. The cytotoxicity of the nanocelluloses was analyzed using colorimetric assays and the clonogenic assay, and genotoxicity by the in vitro micronucleus assay in human alveolar epithelial cells (A549), human osteoblasts (MG-63) and Chinese hamster fibroblasts (V79). Induction of reactive oxygen species (ROS) and cellular internalization were also studied in A549 cells. Cytotoxicity was observed through the clonogenic assay, mainly in the case of CNC, but not in the remaining assays, with no induction of ROS. All nanocelluloses, at some of the concentrations tested, induced micronuclei and/or nucleoplasmic bridges in one of the cellular models. Furthermore, the internalization of CNF and CMF, but not of CNC was visualized in A549 cells. These results aim to contribute to preventing exposure to potentially hazardous cellulosic materials, seeking to boost the development of innovative and safer materials.Projeto ToxApp4NanoCELFI – Uma abordagem de toxicologia preditiva para a caracterização dos potenciais efeitos respiratórios de fibras de nanocelulose funcionalizadas num sistema de co-cultura (PTDC/SAU-PUB/32587/2017).info:eu-repo/semantics/publishedVersio
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