45 research outputs found

    Influence of mechanical strains on electromagnetic signals of a microstrip antenna. FEM/BIM model

    Get PDF
    A hybrid numerical technique is proposed for a characterization of the radar cross section of a microstrip patch antenna residing in a dielectric filled cavity which is loaded by a sinusoidal mechanical pressure. A new 3D hexahedral finite element is developed in order to take into account the deformed shape of the antenna within the electromagnetic computations. The numerical tool combines the finite element and boundary integral methods to formulate a system for the solution of the fields at the aperture and those inside the cavity. In this work, numerical examples are presented for demonstrating the ability and the validity of the hexahedral element

    Modeling DNA Structure, Elasticity and Deformations at the Base-pair Level

    Full text link
    We present a generic model for DNA at the base-pair level. We use a variant of the Gay-Berne potential to represent the stacking energy between neighboring base-pairs. The sugar-phosphate backbones are taken into account by semi-rigid harmonic springs with a non-zero spring length. The competition of these two interactions and the introduction of a simple geometrical constraint leads to a stacked right-handed B-DNA-like conformation. The mapping of the presented model to the Marko-Siggia and the Stack-of-Plates model enables us to optimize the free model parameters so as to reproduce the experimentally known observables such as persistence lengths, mean and mean squared base-pair step parameters. For the optimized model parameters we measured the critical force where the transition from B- to S-DNA occurs to be approximately 140pN140{pN}. We observe an overstretched S-DNA conformation with highly inclined bases that partially preserves the stacking of successive base-pairs.Comment: 15 pages, 25 figures. submitted to PR

    Enrichment of anaerobic syngas-converting bacteria from thermophilic bioreactor sludge

    Get PDF
    Thermophilic (55 °C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2, and CO2) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate – cultures T-Syn-CO. Incubation with syngas and CO caused a rapid decrease in the microbial diversity of the anaerobic consortium. T-Syn and T-Syn-CO showed identical microbial composition and were dominated by Desulfotomaculum and Caloribacterium species. Incubation initiated with CO resulted in the enrichment of bacteria from the genera Thermincola and Thermoanaerobacter. Methane was detected in the first two to three transfers of T-Syn, but production ceased afterward. Acetate was the main product formed by T-Syn and T-Syn-CO. Enriched T-CO cultures showed a two-phase conversion, in which H2 was formed first and then converted to acetate. This research provides insight into how thermophilic anaerobic communities develop using syngas/CO as sole energy and carbon source can be steered for specific end products and subsequent microbial synthesis of chemicals.This study has been financially supported by FEDER funds through the Operational Competitiveness Programme (COMPETE) and by national funds through the Portuguese Foundation for Science and Technology (FCT) in the frame of the project FCOMP-01-0124-FEDER-027894. Financial support from FCT and the European Social Fund (POPH-QREN) through the PhD grant SFRH/BD/48965/2008 attributed to J.I.A. is gratefully acknowledged. A.J.M. Stams acknowledges grants from CW-TOP 700.55.343 and ALW 819.02.014 of the Netherlands Science Foundation (NWO), Consolider-CSD 2007-00055 and ERC (323009)

    Relational development in children with cleft lip and palate: influence of the waiting period prior to the first surgical intervention and parental psychological perceptions of the abnormality:

    Get PDF
    BACKGROUND: The birth of a child with a cleft lip, whether or not in association with a cleft palate, is a traumatic event for parents. This prospective, multidisciplinary and multi-centre study aims to explore the perceptions and feelings of parents in the year following the birth of their child, and to analyse parent-child relationships. Four inclusion centres have been selected, differing as to the date of the first surgical intervention, between birth and six months. The aim is to compare results, also distinguishing the subgroups of parents who were given the diagnosis in utero and those who were not. METHODS/DESIGN: The main hypothesis is that the longer the time-lapse before the first surgical intervention, the more likely are the psychological perceptions of the parents to affect the harmonious development of their child. Parents and children are seen twice, when the child is 4 months (T0) and when the child is one year old (T1). At these two times, the psychological state of the child and his/her relational abilities are assessed by a specially trained professional, and self-administered questionnaires measuring factors liable to affect child-parent relationships are issued to the parents. The Alarme Detresse BeBe score for the child and the Parenting Stress Index score for the parents, measured when the child reaches one year, will be used as the main criteria to compare children with early surgery to children with late surgery, and those where the diagnosis was obtained prior to birth with those receiving it at birth. DISCUSSION: The mental and psychological dimensions relating to the abnormality and its correction will be analysed for the parents (the importance of prenatal diagnosis, relational development with the child, self-image, quality of life) and also, for the first time, for the child (distress, withdrawal). In an ethical perspective, the different time lapses until surgery in the different protocols and their effects will be analysed, so as to serve as a reference for improving the quality of information during the waiting period, and the quality of support provided for parents and children by the healthcare team before the first surgical intervention. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00993993

    Carbon Dioxide Utilisation -The Formate Route

    Get PDF
    UIDB/50006/2020 CEEC-Individual 2017 Program Contract.The relentless rise of atmospheric CO2 is causing large and unpredictable impacts on the Earth climate, due to the CO2 significant greenhouse effect, besides being responsible for the ocean acidification, with consequent huge impacts in our daily lives and in all forms of life. To stop spiral of destruction, we must actively reduce the CO2 emissions and develop new and more efficient “CO2 sinks”. We should be focused on the opportunities provided by exploiting this novel and huge carbon feedstock to produce de novo fuels and added-value compounds. The conversion of CO2 into formate offers key advantages for carbon recycling, and formate dehydrogenase (FDH) enzymes are at the centre of intense research, due to the “green” advantages the bioconversion can offer, namely substrate and product selectivity and specificity, in reactions run at ambient temperature and pressure and neutral pH. In this chapter, we describe the remarkable recent progress towards efficient and selective FDH-catalysed CO2 reduction to formate. We focus on the enzymes, discussing their structure and mechanism of action. Selected promising studies and successful proof of concepts of FDH-dependent CO2 reduction to formate and beyond are discussed, to highlight the power of FDHs and the challenges this CO2 bioconversion still faces.publishersversionpublishe

    Caractérisation expérimentale des propriétés physiques et mécaniques de FGPM Ni/BaTiO3_3

    No full text
    International audienceThis study focuses on the experimental characterization of the physical and mechanical properties of FGM/FGPM. These materials present a controlled variation of the properties at the thickness level. Ni/BaTiO3_3 samples have been developed by the SPS sintering technique. The variation of thermal conductivity across the thickness was determined using the transient planar source method. However, the small size of the samples does not allow the use of standard techniques to measure the elastic constants. An alternative protocol based on the use of ultrasonic waves has been proposed to overcome this difficultyCette étude porte sur la caractérisation expérimentale des propriétés physiques et mécaniques de matériaux FGM /FGPM. Ces matériaux présentent une variation contrôlée des propriétés au niveau de l'épaisseur. Des échantillons Ni/BaTiO3 ont ainsi été élaborés par la technique originale de frittage SPS. La variation de la conductivité thermique dans l'épaisseur a été déterminée à l'aide de la méthode de la source plane transitoire. Cependant, la petite taille des échantillons ne permet pas d'utiliser les techniques standard pour mesurer les constantes élastiques. Un protocole alternatif basé sur l'utilisation des ondes ultrasons est donc proposé pour palier à cette difficulté

    Indoor air-quality control by a fuzzy-reasoning machine in naturally ventilated buildings

    No full text
    This paper investigates the performance of a fuzzy reasoning machine for the control of indoor air quality in naturally ventilated buildings. Simulations have been performed using a new airflow and pollutant transport model, which has been developed and validated for this purpose; CO2 concentration was used as the indoor-air quality (IAQ) index for these simulations. Results have shown that satisfactory IAQ levels can be maintained, while good stability of the control parameter (i.e. window opening area) was achieved. The impact of such a controller on indoor-air temperature was also studied. The performances were not as good as expected, but were not negligible when compared with the normal conditions of use of the building.
    corecore