336 research outputs found

    Engineering tools for robust creep modelling

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    High temperature creep is often dealt with simplified models to assess and predict the future behavior of materials and components. Also, for most applications the creep properties of interest require costly long-term testing that limits the available data to support design and life assessment. Such test data sets are even smaller for welded joints that are often the weakest links of structures. It is of considerable interest to be able to reliably predict and extrapolate long term creep behavior from relatively small sets of supporting creep data. For creep strain, the current tools for model verification and quality assurance are very limited. The ECCC PATs can be adapted to some degree but the uncertainty and applicability of many models are still questionable outside the range of data. In this thesis tools for improving the model robustness have been developed. The toolkit includes creep rupture, weld strength and creep strain modeling improvements for uniaxial prediction. The applicability is shown on data set consisting of a selection of common high temperature steels and the oxygen-free phosphorous doped (OFP) copper. The steels assessed are 10CrMo9-10 (P22), 7CrWVMoNb9-6 (P23), 7CrMoVTiB10-10 (P24), 14MoV6-3 (0.5CMV), X20CrMoV11-1 (X20), X10CrMoVNb9-1 (P91) and X11CrMoWVNb9-1-1 (E911). The work described in this thesis has provided simple yet well performing tools to predict creep strain and life for material evaluation, component design and life assessment purposes. The uncertainty related to selecting the type of material model or determining weld strength factors has been reduced by the selection procedures and by linking the weld behavior to the base material master equation. Much of the resulting improvements and benefits are related to the reduced requirements for supporting creep data. The simplicity and robustness of the new tools also makes them easy to implement for both analytical and numerical solutions

    Engineering tools for robust creep modeling

    Get PDF
    High temperature creep is often dealt with simplified models to assess and predict the future behavior of materials and components. Also, for most applications the creep properties of interest require costly long-term testing that limits the available data to support design and life assessment. Such test data sets are even smaller for welded joints that are often the weakest links of structures. It is of considerable interest to be able to reliably predict and extrapolate long term creep behavior from relatively small sets of supporting creep data. For creep strain, the current tools for model verification and quality assurance are very limited. The ECCC PATs can be adapted to some degree but the uncertainty and applicability of many models are still questionable outside the range of data. In this thesis tools for improving the model robustness have been developed. The toolkit includes creep rupture, weld strength and creep strain modeling improvements for uniaxial prediction. The applicability is shown on data set consisting of a selection of common high temperature steels and the oxygen-free phosphorous doped (OFP) copper. The steels assessed are 10CrMo9-10 (P22), 7CrWVMoNb9-6 (P23), 7CrMoVTiB10-10 (P24), 14MoV6-3 (0.5CMV), X20CrMoV11-1 (X20), X10CrMoVNb9-1 (P91) and X11CrMoWVNb9-1-1 (E911). The work described in this thesis has provided simple yet well performing tools to predict creep strain and life for material evaluation, component design and life assessment purposes. The uncertainty related to selecting the type of material model or determining weld strength factors has been reduced by the selection procedures and by linking the weld behavior to the base material master equation. Much of the resulting improvements and benefits are related to the reduced requirements for supporting creep data. The simplicity and robustness of the new tools also makes them easy to implement for both analytical and numerical solutions

    GESTÃO ESTRATÉGICA E O USO DO BALANCED SCORECARD

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    Em um ambiente onde o processo de mudança é contínuo, a sobrevivência das empresas tornou-se uma tarefa complexa e difícil. A continuidade dos negócios está associada à implementação de uma estratégia competitiva, que depende fundamentalmente da viabilidade de sua implementação, e da forma como a organização desenvolve seus sistemas de informações gerenciais. Porém utilizar-se de estratégias bem fundamentadas, não basta para obter sucesso, é necessário saber executá-las e usar de ferramentas que forneçam meios para medir o seu desempenho. Este artigo faz uma abordagem sobre o processo estratégico, iniciando com um breve histórico da questão estratégica, passando para conceitos de planejamento estratégico e estratégia competitiva, onde finalmente traz o Balanced Scorecard como meio de gestão por indicadores estratégicos, uma ferramenta que traduz a visão da empresa e seus objetivos em uma série de indicadores financeiros e não-financeiros, alicerçados sobre quatro perspectivas distintas que são: a perspectiva financeira, a perspectiva do cliente, a perspectiva de processos internos e a perspectiva de aprendizado e crescimento

    Innovation and qualification of LEU research reactor fuels and materials

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    Two projects within the Euratom Research and Training Programmes 2014–2018 and 2019–2020 are focused on the innovation and qualification of novel nuclear fuels for conversion from highly-enriched uranium to low-enriched uranium (LEU) and for securing the supply chain of EU research reactors into the future. The LEU-FOREvER project is drawing to a close and has made significant progress in developing and demonstrating the uranium-molybdenum fuel system, demonstrating the viability of a high-density uranium-silicide fuel for EU high-performance research reactors (BR2, RHF, FRM-II, JHR). This project has significantly increased the fabrication know-how and fuel performance understanding of the uranium-molybdenum and high-density uranium-silicide dispersion fuel systems. Further, a new, innovative and increased performance design for the LVR-15 research reactor fuel assembly has been engineered and a demonstration is planned in 2022. In the EU-QUALIFY project, which began in 2020, the planning of four demonstration irradiation tests has been nearly completed and fabrication development of the various fuel systems is ongoing, including the establishment of an EU monolithic uranium-molybdenum fabrication capability. It is expected that the results of this project will begin or complete the data gathering necessary for generic fuel qualification of the LEU uranium-molybdenum dispersion and monolithic fuel systems, and the LEU high-density uranium-silicide fuel system

    Insights gained from a systematic reanalysis of a successful model-facilitated change process in health care

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    Health care is a complex system with multiprofessional staff and multiple patient care pathways. Time pressure and minimal margins for error make it challenging to implement new policies or procedures, no matter how desirable. Changes in health care also requires the participation of the staff. System dynamics (SD) simulations can lead to shared systems understanding and allows for the development and testing of new scenarios in silico before implementing solutions. However, research shows that the actual implementation rate of simulations is low. This paper presents a reanalysis of a successful change project in health care combining SD principles with basic action research (AR) premises. The analysis was done by a multidisciplinary research group using qualitative methodology and identifies that a fruitful combination of AR inquiry and SD modelling potentially can improve implementation rates.publishedVersio

    Galactic Cosmic Rays at Mars and Venus: Temporal Variations from Hours to Decades Measured as the Background Signal of Onboard Micro-Channel Plates

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    A Micro-Channel Plate (MCP) is a widely used component for counting particles in space. Using the background counts of MCPs on Mars Express and Venus Express orbiters operated over 17 years and 8 years, respectively, we investigate the galactic cosmic ray (GCR) characteristics in the inner solar system. The MCP background counts at Mars and Venus on a solar cycle time scale exhibit clear anti-correlation to the sunspot number. We conclude that the measured MCP background contain the GCR information. The GCR characteristics measured using the MCP background at Mars show features that are consistent with the ground-based measurement in solar cycle 24. The time lag between the sunspot number and the MCP background at Mars is found ~9 months. The shorter-term background data recorded along the orbits (with a time scale of several hours) also show evident depletion of the background counts due to the absorption of the GCR particles by the planets. Thanks to the visible planetary size change along an orbit, the GCR contribution to the MCP background can be separated from the internal contribution due to the \b{eta}-decay. Our statistical analysis of the GCR absorption signatures at Mars implies that the effective absorption size of Mars for the GCR particles have a >100 km larger radius than the solid Martian body.Comment: Submitted to ApJ (2022-03-19

    Fonación de la voz cantada en estudiantes del IV y V ciclo de primaria de la Institución Educativa Particular “Santa Teresita”, Surco

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    La forma de aprender de los niños es por imitación; vocabulario, gestos y rutinas son aprendidas desde la infancia, el canto también es aprendido e imitado, primero por los padres, posteriormente la posta la tomarán los maestros y tutores, por eso la importancia de tener buenas referencias vocales. El presente trabajo de investigación determinó el nivel actual de fonación de la voz cantada, midiendo la respiración, emisión, articulación y si es adecuada para el canto. A partir de los resultados de la muestra de estudio se podrá sugerir propuestas para la mejora de la fonación de la voz cantada. Su enfoque es cuantitativo, con diseño no experimental de corte transversal, es decir, recolectan datos de nuestra variable de estudio en un momento determinado, de modo que proporcione una visión real de la situación en que evidentemente se encuentra la fonación de la voz cantada en los estudiantes. La población estuvo constituida por 360 estudiantes del IV y V ciclo de primaria de la institución educativa “Santa Teresita” de Surco, la muestra estuvo constituida por 56 estudiantes asistentes al taller de coro de la institución. Se utilizó una rúbrica como instrumento de evaluación validada a través de juicio de expertos más su respectiva confiabilidad a través del alfa de cronbach. Los resultados de la evaluación reportaron que el 37.50% de estudiantes se encuentra en un nivel deficiente en cuanto a la fonación de la voz cantada, el 30,36% en nivel de proceso y el 32,14% en un nivel de logro. El presente resultado de esta investigación será el punto de partida para proponer un plan educativo musical, para la mejora de la fonación de la voz cantada, dejando la posibilidad de futuras investigaciones.The way children learn is by imitation; Vocabulary, gestures and routines are learned from childhood, the song is also learned and imitated, first by the parents, then the post will be taken by the teachers and tutors, that is why is important of having good vocal references. The present research work determinated the current phonation level of the sung voice, measuring the respiration, emission, articulation and if it is suitable for singing. From the results of the study sample it will be possible to suggest proposals for the improvement of the phonation of the sung voice. Its approach is quantitative, with a non-experimental cross-sectional design, that is, it collects data from our study variable at a given moment, so that it provides a real vision of the situation of the sung voice is evidently found in the students. The population was constituted by 360 students of the IV and V primary cycle of the educational institution "Santa Teresita" of Surco, the sample was constituted by 56 students attending the choir workshop of the institution. A rubric was used as an evaluation instrument validated through expert judgment plus its respective reliability through cronbach's alpha. The results of the evaluation reported that 37.50% of students are at a deficient level in terms of the phonation of the sung voice, 30.36% at the process level and 32.14% at an achievement level. The present result of this investigation will be the starting point to propose a musical educational plan, for the improvement of the phonation of the sung voice, giving the possibility of future investigations.Tesi

    European retrospective study of real-life haemophilia treatment

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    IntroductionHaemophilia treatment varies significantly between individuals, countries and regions and details of bleed rates, factor consumption and injection frequency are often not available.AimTo provide an overview of the FVIII/FIX treatment practice and outcome for patients with haemophilia A (HA) or haemophilia B (HB) across Europe.MethodsNon‐interventional, 12‐month retrospective study where anonymized data were retrieved from haemophilia centres/registers in Belgium, France, Germany, Italy, Spain, Sweden and the United Kingdom. Male patients (all ages) receiving coagulation factor treatment 24 months prior to the study, with basal FVIII/FIX levels ≤5 IU dL−1, without inhibitors, were included. Data were summarized descriptively.ResultsIn total, 1346 patients with HA and 312 with HB were included in the analysis; 75% and 57% had severe disease (FVIII/FIX < 1 IU dL−1) respectively. Prophylaxis was most common for severe haemophilia, especially for children, whereas on‐demand treatment was more common for moderate haemophilia in most countries. The mean (SD) prescribed prophylactic treatment ranged from 67.9 (30.4) to 108.4 (78.1) (HA) and 32.3 (10.2) to 97.7 (32.1) (HB) IU kg−1 per week, across countries. Most patients on prophylaxis were treated ≥3 times/week (HA) or two times/week (HB). The median annual bleeding rate (ABR) for patients on prophylaxis ranged from 1.0 to 4.0 for severe HA, and from 1.0 to 6.0 for severe HB, while those with moderate haemophilia generally had slightly higher ABRs. Median ABRs for on‐demand‐treated severe HA ranged from 4.5 to 18.0, and for HB, 1.5 to 14.0.ConclusionTreatment practice varied greatly between centres and countries and patients treated on‐demand and prophylactically both experienced bleeds, emphasizing the need for further optimization of care
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