Kinetics of laccase mediator system delignification of an Eucalyptus globulus Kraft pulp

Comunicação da qual só está disponível o resumo.Laccase mediator system (LMS) was applied to one industrial Eucalyptus globulus kraft pulp with kappa numbers 15.2, using violuric acid (VA) as mediator. The objective of the present work is to quantify the influence of the reaction conditions on the delignification rate and extent, establishing the kinetic equations. The effects of oxygen pressure, laccase and mediator charges, and reaction time on delignification were evaluated. The kinetic studies were carried out in a 1.5 L jacketed reactor with temperature control and magnetic mixer. The experiments were carried out with 10 grams of pulp at very low consistency (0.6%) in order to minimize inter-fibre mass transfer resistances. The oxygen pressure was varied between 1 and 7 bar and no significant differences were observed in terms of delignification rate and extent, at a given charge of laccase and mediator. The laccase (EC 1.10.3.2) charge was ranged between 10 and 250 IU per gram of pulp and the mediator between 10 and 70 mg per gram of pulp. The presence of mediator is required because the enzyme cannot diffuse into the porous structure of the fibre wall, where lignin should be oxidised. The delignification potential of the LMS was evaluated by measuring the kappa number of the pulp, after alkaline extraction. Control tests similar to the LMS followed by alkaline extraction, but without enzyme, were carried out and the mean value of kappa number was 14.04. The decrease of the kappa number of the pulp from 15.2 to 14.04 can be interpreted as the consequence of the extraction of some fragments of lignin during the two stages. This procedure enable us to access the real effect of laccase. The hexeneuronic acid (HexA) has, particularly in hardwood pulps, an important contribution to the kappa number value. However, the experimental data have shown that LMS does not remove significantly the HexA, which is in good agreement with the literature. So, the kappa number can be used to evaluate the potential of LMS to lignin extraction. For the levels of laccase 50 IU per gram and 40 mg of VA per gram, the delignification was reached 37%, which is a good result. The profile of kappa number with reaction time follows an exponential trend. In addition, the initial rate methodology is being used to quantify the influence of laccase and mediator concentrations on the kinetic rate. The data have shown that the delignification rate exhibits a linear dependence on the mediator concentration, for the low range tested. The effect of laccase charge seems to be lower. The experimental data are under exploitation

Thin Film (High Temperature) Superconducting Radiofrequency Cavities for the Search of Axion Dark Matter

5 pages, 6 figures. v2: minor updates after referee comments, matches published version in IEEEThe axion is a hypothetical particle which is a candidate for cold dark matter. Haloscope experiments directly search for these particles in strong magnetic fields with RF cavities as detectors. The Relic Axion Detector Exploratory Setup (RADES) at CERN in particular is searching for axion dark matter in a mass range above 30 $\mu$eV. The figure of merit of our detector depends linearly on the quality factor of the cavity and therefore we are researching the possibility of coating our cavities with different superconducting materials to increase the quality factor. Since the experiment operates in strong magnetic fields of 11 T and more, superconductors with high critical magnetic fields are necessary. Suitable materials for this application are for example REBa$_2$Cu$_3$O$_{7-x}$, Nb$_3$Sn or NbN. We designed a microwave cavity which resonates at around 9~GHz, with a geometry optimized to facilitate superconducting coating and designed to fit in the bore of available high-field accelerator magnets at CERN. Several prototypes of this cavity were coated with different superconducting materials, employing different coating techniques. These prototypes were characterized in strong magnetic fields at 4.2 K.This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 730871 (ARIES-TNA). BD and JG acknowledge funding through the European Research Council under grant ERC-2018-StG-802836 (AxScale). We also acknowledge funding via the Spanish Agencia Estatal de Investigacion (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) under project PID2019- 108122GB-C33, and the grant FPI BES-2017-079787 (under project FPA2016-76978-C3-2-P). Furthermore we acknowledge support from SuMaTe RTI2018-095853-B-C21 from MICINN co-financed by the European Regional Development Fund, Center of Excellence award Severo Ochoa CEX2019- 000917-S and CERN under Grant FCCGOV-CC-0208 (KE4947/ATS).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Os saberes e o fazer pedagógico: uma integração entre teoria e prática Knowledges and pedagogical practice: an integration between theory and practice

O saber-fazer docente desperta o interesse dos educadores que tratam deste tema sob diferentes ópticas: competência do professor; integração do conhecimento subjacente do aluno; do professor reflexivo-crítico; da proposta de educação libertadora e prática política; e reconhecimento da complexidade da educação e reflexão sobre a fragmentação das disciplinas, dificultando a interdisciplinaridade. Este estudo descritivo qualitativo trata de um processo de ensino a partir de análises teóricas e empíricas, proposto por Edgar Morin, ocorrido na disciplina Didática, no Mestrado em Educação·em Saúde da UNIFOR, em 2004. Participaram da pesquisa vinte mestrandos de várias categorias profissionais. Os resultados demonstram que a dinâmica empregada propiciou a integração, maior compreensão dos conceitos e obtenção de clima descontraído para aprendizagem. Concluímos que estratégias tais como jogo; dinâmicas grupais e psicodrama pedagógico favorecem a participação e a expressão de sentimentos, permitem a interação, assimilação e compartilhamento das experiências na elaboração coletiva do conhecimento.<br>The teaching know-how arouses the interest of educators who deal with this subject from different points of view: teacher's competence; integration of the student's hidden knowledge; the reflexive-critical teacher; proposal for liberating education and political practice; the recognition of educational complexity and reflection on the fragmentation of disciplines which make difficult the interdisciplinariety. This descriptive-qualitative study is about a teaching process based on theoretical and empirical analyses, proposed by Edgar Morin, and took place in the discipline of didactics from the Master Course of Health and Education at UNIFOR in 2004. Twenty Master students from several professional categories participated in the event. The outcomes showed that the dynamics applied to the study provided greater understanding of concepts, integration, as well as relaxing environment concerning the learning process. It is concluded that strategies such as games, group dynamics and pedagogical psychodrama provide participation and the expression of feelings, interaction, assimilation and experiences shared through the collective construction of knowledge