975 research outputs found

    Large critical current density improvement in Bi-2212 wires through groove-rolling process

    Full text link
    Recently the interest about Bi-2212 round wire superconductor for high magnetic field use has been enhancing despite the fact that an increase of the critical current is still needed to boost its successful use in such applications. Recent studies have demonstrated that the main obstacle to current flow, especially in long wires, is the residual porosity inside these Powder-In-Tube processed conductors which develops in bubbles-agglomeration when the Bi-2212 melts. Through this work we tried to overcome this issue acting on the wire densification by changing the deformation process. Here we show the effects of groove-rolling versus drawing process on the critical current density JC and on the microstructure. In particular, groove-rolled multifilamentary wires show a JC increased by a factor of about 3 with respect to drawn wires prepared with the same Bi-2212 powder and architecture. We think that this approach in the deformation process is able to produce the required improvements both because the superconducting properties are enhanced and because it makes the fabrication process faster and cheaper

    Escribir en el inicio de la universidad: el caso de las carreras de ciencias biológicas y profesorado en ciencias biológicas

    Get PDF
    La escritura tiene una notable importancia para el aprendizaje de las ciencias. En este trabajo se categorizan las tareas de escritura propuestas en el material de estudio de una asignatura introductoria a las carreras de Ciencias Biológicas y Profesorado en Ciencias Biológicas, se caracteriza la valoración que realizan los estudiantes respecto de estas actividades y se evalúan las dificultades que tienen los alumnos para construir textos. Para ello, se utilizan y adaptan categorías construidas en investigaciones previas. Se destaca el valor que la asignatura otorga a la interpretación de consignas y a la reelaboración del contenido después de la lectura del material de estudio, se da cuenta de las dificultades de los alumnos al identificar puntos de vista sobre un tema y se analiza la relación entre la formulación de una consigna y las producciones de los alumnos

    Turbulent Drag Reduction by Biopolymers in Large Scale Pipes

    Get PDF
    In this work, we describe drag reduction experiments performed in a large diameter pipe (i.d. 100mm) using a semirigid biopolymer Xanthan Gum (XG). The objective is to build a self-consistent data base which can be used for validation purposes. To aim this, we ran a series of tests measuring friction factor at different XG concentrations (0.01, 0.05, 0.075, 0.1, and 0.2% w/w XG) and at different values of Reynolds number (from 758 to 297,000). For each concentration, we obtain also the rheological characterization of the test fluid. Our data is in excellent agreement with data collected in a different industrial scale test rig. The data is used to validate design equations available from the literature. Our data compare well with data gathered in small scale rigs and scaled up using empirically based design equations and with data collected for pipes having other than round cross section. Our data confirm the validity of a design equation inferred from direct nu- merical simulation (DNS) which was recently proposed to predict the friction factor. We show that scaling procedures based on this last equation can assist the design of piping systems in which polymer drag reduction can be exploited in a cost effective way

    Alinhamento das práticas da gestão e curadoria da informação com as da segurança da informação

    Get PDF
    A evolução da tecnologia proporcionou uma mudança do cenário na sociedade da informação. Ela possibilitou o surgimento de fenómenos como o big data, no qual o crescimento exponencial de informação atinge a sociedade a cada minuto. Com isso, garantir a confidencialidade, integridade e disponibilidade da informação tornou-se uma tarefa fundamental. As áreas da segurança da informação e gestão e curadoria da informação têm como objetivo garantir isso aos interessados, sendo, no entanto ainda pouco estudada a extensão das suas sobreposições ou complementaridades mútuas. Este trabalho propõe uma contribuição para essa questão, apresentando uma proposta de alinhamento entre os processos e práticas da segurança da informação e da gestão e curadoria da informação, de maneira a garantir melhor eficácia e eficiência em organizações nas quais essas áreas de interesse coexistam. Para tal, utilizou-se o método de pesquisa bibliográfica, primeiro para elucidação e explanação dos principais conceitos dessas áreas e respetivos sistemas de gestão, e de seguida para a identificação de estudos exploratórios de análises de tendências e exemplos de investigação. Conclui-se que é possível a sinergia dos processos, e que uma aplicação conjunta dos dois sistemas de gestão melhoraria a eficácia e a eficiência numa organização.The evolution of technology had changed the information society. It enabled the appearance of a phenomena know as big data, which deals with the exponential growth of information that reaches society every minute. Thus, ensuring the confidentiality, integrity, and availability of information has become a fundamental task. The domains of information security and information management and curation also have the objective to guarantee this to the stakeholders. This dissertation aims to present a contribution to this matter, a proposition of alignment between the information security and information management and curation processes and practices, as a means to guarantee better effectiveness and efficiency in organizations in which these areas of interest coexist. For this purpose, bibliographic research method was used to elucidate and explain the main concepts of these areas and their respective management system, and to identify exploratory studies of trend analysis and research examples. In conclusion it is possible to have a synergy of processes and that a joint application of both management systems would improve its effectiveness and efficiency in an organizations

    Heat capacity, configurational heat capacity and fragility of hydrous magmas

    Get PDF
    International audienceThe glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results

    Novel homozygous GBA2 mutation in a patient with complicated spastic paraplegia

    Get PDF
    Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurological disorders characterized primarily by a pyramidal syndrome with lower limb spasticity, which can manifest as pure HSP or associated with a number of neurological or non-neurological signs (i.e., complicated HSPs). The clinical variability of HSPs is associated with a wide genetic heterogeneity, with more than eighty causative genes known. Recently, next generation sequencing (NGS) has allowed increasing genetic definition in such a heterogeneous group of disorders. We report on a 56- year-old man affected by sporadic complicated HSP consisting of a pyramidal syndrome, cerebellar ataxia, congenital cataract, pes cavus, axonal sensory-motor peripheral neuropathy and cognitive decline. Brain MRI showed cerebellar atrophy and thin corpus callosum. By NGS we found a novel homozygous biallelic c.452-1G > C mutation in the b-glucosidase 2 gene (GBA2), known to be causative for autosomal recessive hereditary spastic paraplegia type 46 (SPG46). The rarity of this inherited form besides reporting on a novel mutation, expands the genetic and clinical spectrum of SPG46 related HSP

    Electronic witness system in IVF—patients perspective

    Get PDF
    Objective The objective of this study is to evaluate patient concerns about in vitro fertilization (IVF) errors and electronic witness systems (EWS) satisfaction. Design The design of this study is a prospective single-center cohort study. Setting The setting of this study was located in the private IVF center. Patient(s) Four hundred eight infertile patients attending an IVF cycle at a GENERA center in Italy were equipped with an EWS. Intervention(s) Although generally recognized as a very rare event in IVF, biological sample mix-up has been reported in the literature. For this reason, some IVF laboratories have introduced EWS with the aim to further reduce the risk of error during biological samples handling. Participating patients received a questionnaire developed through a Likert scale ranging from 1 to 6. Main outcomes measure(s) Patient concerns about sample mix-up without and with an EWS were assessed. Result(s) 90.4 % of patients expressed significant concerns relating to sample mix-up. The EWS reduced these concerns in 92.1 % of patients, 97.1 % of which were particularly satisfied with the electronic traceability of their gametes and embryos in the IVF laboratory. 97.1 % of patients felt highly comfortable with an IVF center equipped with an EWS. Female patients had a significantly higher appreciation of the EWS when compared to their male partners (p = 0.029). A significant mix-up event occurred in an Italian hospital during the study and patient's satisfaction increased significantly towards the use of the EWS after the event (p = 0.032). Conclusion(s) EWS, by sensibly reducing the risk for sample mix-up in IVF cycles, has been proved to be a trusted strategy from patient's perspective

    Calorimetric properties of magmas

    Get PDF

    Assembly of a Tripeptide and Anti-Inflammatory Drugs into Supramolecular Hydrogels for Sustained Release

    Get PDF
    5siSupramolecular hydrogels offer interesting opportunities for co-assembly with drugs towards sustained release over time, which could be achieved given that the drug participates in the hydrogel nanostructure, and it is not simply physically entrapped within the gel matrix. dLeu-Phe-Phe is an attractive building block of biomaterials in light of the peptide’s inherent biocompatibility and biodegradability. This study evaluates the assembly of the tripeptide in the presence of either of the anti-inflammatory drugs ketoprofen or naproxen at levels analogous to commercial gel formulations. Fourier-transformed infrared (FT-IR), circular dichroism, Thioflavin T fluorescence, transmission electron microscopy (TEM), and oscillatory rheometry are used. Drug release over time is monitored by means of reverse-phase high performance liquid chromatography, and shows different kinetics for the two drugs.openopenKurbasic, Marina; Romano, Chiara Damiana; Garcia Fernandez, Ana Maria; Kralj, Slavko; Marchesan, SilviaKurbasic, Marina; Romano, CHIARA DAMIANA; GARCIA FERNANDEZ, ANA MARIA; Kralj, Slavko; Marchesan, Silvi
    • …
    corecore