716 research outputs found

    Kalman-variant estimators for state of charge in lithium-sulfur batteries

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    Lithium-sulfur batteries are now commercially available, offering high specific energy density, low production costs and high safety. However, there is no commercially-available battery management system for them, and there are no published methods for determining state of charge in situ. This paper describes a study to address this gap. The properties and behaviours of lithium-sulfur are briefly introduced, and the applicability of ‘standard’ lithium-ion state-of-charge estimation methods is explored. Open-circuit voltage methods and ‘Coulomb counting’ are found to have a poor fit for lithium-sulfur, and model-based methods, particularly recursive Bayesian filters, are identified as showing strong promise. Three recursive Bayesian filters are implemented: an extended Kalman filter (EKF), an unscented Kalman filter (UKF) and a particle filter (PF). These estimators are tested through practical experimentation, considering both a pulse-discharge test and a test based on the New European Driving Cycle (NEDC). Experimentation is carried out at a constant temperature, mirroring the environment expected in the authors' target automotive application. It is shown that the estimators, which are based on a relatively simple equivalent-circuit–network model, can deliver useful results. If the three estimators implemented, the unscented Kalman filter gives the most robust and accurate performance, with an acceptable computational effort

    The effect of fasting on the ultrastructure of the hypothalamic arcuate nucleus in young rats

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    In the present study, we described ultrastructural changes occurring in the neurons of the hypothalamic arcuate nucleus after food deprivation. Young male Wistar rats (5 months old, n = 12) were divided into three groups. The animals in Group I were used as control (normally fed), and the rats in Groups II and III were fasted for 48 hours and 96 hours, respectively. In both treated groups, fasting caused rearrangement of the rough endoplasmic reticulum forming lamellar bodies and membranous whorls. The lamellar bodies were rather short in the controls, whereas in the fasting animals they became longer and were sometimes participating in the formation of membranous whorls composed of the concentric layers of the smooth endoplasmic reticulum. The whorls were often placed in the vicinity of a very well developed Golgi complex. Some Golgi complexes displayed an early stage of whorl formation. Moreover, an increased serum level of 8-isoprostanes, being a reliable marker of total oxidative stress in the body, was observed in both fasting groups of rats as compared to the control

    Ultrastructural observations on the hypothalamic arcuate nuclei of aged rats in the fasting/refeeding model

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    The arcuate nucleus of the hypothalamus (ARH) is involved in the control of energy homeostasis. This is the first study on the ultrastructural response of ARH neurons in aged rats after short-term fasting and subsequent refeeding. Male Wistar rats (24 weeks old) were fasted for 48 or 96 hours and were then refed for 24 hours. The controls were normally fed. The rats received water ad libitum. In both groups of fasting animals, we observed a rearrangement of the arcuate rough endoplasmic reticulum (RER) and Golgi complexes to form membranous whorls. Moreover, refeeding for 24 hours did not reverse this process. The RER was frequently found to be well organized into lamellar bodies composed of several cisternae. The membranous whorls were composed of concentric layers of endoplasmic reticulum and Golgi complexes. In addition, multiform lipofuscin granules were observed in close relationship with Golgi complexes and membranous whorls. Lipofuscin granules within the neurons of the arcuate nucleus are assumed to be a morphological manifestation of oxidative stress phenomena, which are presumably implicated in the formation of membranous whorls in both fasting and fasting/refed animals. This observation correlates with a significant increase in 8-isoprostane serum levels in the fasting and fasting/refed animals as compared to the fed control rats

    Wyzwania w zarządzaniu zespołami wielokulturowymi

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    The aim of the article is to identify challenges in managing multicultural teams, which, according to the authors, are extremely important in modern human resource management. This paper is based on literature studies and available reports. The authors prove that the challenges associated with the effective management of multicultural teams are very large, especially considering the stereotypes and prejudices related to the cultural diversity of employees and the diverse competences of managers who manage multicultural teams. The main value of the study is to clarify the need to raise the awareness of managers in terms of the development potential of multicultural teams, taking into account both their strengths and weaknesses, while pointing to the need for competence development in managers and their ability to build positive relations between representatives of different cultures.Celem artykułu jest identyfikacja wyzwań w zarządzaniu zespołami wielokulturowymi, które zdaniem autorek są szczególnie ważne we współczesnym zarządzaniu zasobami ludzkimi. Opierając się na różnych źródłach, autorki argumentują, że wyzwania związane ze skutecznym zarządzaniem wielokulturowymi zespołami są bardzo duże, szczególnie mając na uwadze stereotypy i uprzedzenia łączące się z różnorodnością kulturową pracowników oraz zróżnicowane kompetencje menedżerów, którzy zarządzają wielokulturowymi zespołami. W pierwszej części artykułu wyjaśniono pojęcia wielokulturowości i zarządzania międzykulturowego. W kolejnej części przedstawiono atuty i słabości pracy w wielokulturowych zespołach. Następnie opisano kompetencje i najważniejsze zadania menedżerów zespołów wielokulturowych, a w ostatniej części przeanalizowano wyzwania – trudności i problemy w zarządzaniu wielokulturowymi zespołami

    The impact of ex-post legislative evaluations in healthcare:A mixed methods realist evaluation study protocol for conducting case studies

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    Background:Recent studies on the impact of ex-post legislative evaluations show that there are different types of impact and different factors that can influence it. These include the context of a legislative evaluation, research quality, and interactions between researchers and other actors within the evaluation process. However, thorough empirical research in this area is lacking. This warrants empirical research into the factors that influence the impact of ex-post legislative evaluations, so these insights can be used to increase the likelihood of ex-post legislative evaluations having an impact.Methods and analysis:In this protocol, we report on the realist evaluation methodology that will be used to evaluate the impact of three ex-post legislative evaluations in the Dutch healthcare sector. The mixed methods realist evaluation approach will facilitate this theory-driven, qualitative research. The study will consist of the following three steps: (1) Initial programme theory development, (2) theory validation, and (3) theory refinement. Knowledge from two scoping reviews conducted previously, and two subsequent expert meetings will form the basis for developing the initial programme theory. During this study, three case studies will be conducted, in which three individual ex-post legislative evaluations will be examined. Specific methods for data collection will include: documentary review, observation, structured questionnaires and focus group discussions with purposefully identified key stakeholders. Using the framework approach, the data will be analysed thematically in a within-case analysis followed by across-case analysis. Discussion:This protocol provides insight into how the study will be conducted. As this study uses multiple qualitative research methods to answer one question, this protocol supports refining data collection procedures. Careful consideration of the approach beforehand can minimise pitfalls, reduce publication bias and improve reproducibility. The protocol therefore specifies how the research question will be answered in detail, and this provides solid guidance for the research process

    Cavity-mediated coupling of antiferromagnetic spin waves

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    Coupling of space-separated oscillators is interesting for quantum and communication technologies. In this work, it is shown that two antiferromagnetic oscillators placed inside an electromagnetic cavity couple cooperatively to its terahertz modes and, in effect, hybridized magnon-polariton modes are formed. This is supported by a systematic study of reflection spectra from two parallel-plane slabs of hematite (α\alpha-Fe2_2O3_3), measured as a function of their temperatures and separation distance, and modeled theoretically. The mediating cavity was formed by the crystals themselves and the experiment was performed in a practical distance range of a few millimetres and above room temperature. Cavity-mediated coupling allows for engineering of complex resonators controlled by their geometry and by sharing properties of their components

    Submerged entry nozzle clogging during continuous casting of Al-killed steel

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    Nozzle clogging is a common problem in the production of continuously cast Al-killed steels. Clogging occurs when there are solid inclusions in molten steel at casting temperatures. SENs (Submerged entry nozzles) from continuous casting of Al-killed low alloy steel grades with increased content of sulfur (0,020 to 0,035 % S) were examined. The examinations revealed that the deposits are mainly alumina based, with spinel and sulfur inclusions and some entrapped steel melt. It was concluded that the process of clogging begins when the steel melt infiltrates the refractory and removes the protective zirconia surface, thus allowing the adhesion of fine solid aluminates, which form the deposits

    Search, Filter, Fork, and Link Open Data - The ADEQUATe platform: data- and community-driven quality improvements.

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    The present work describes the ADEQUATe platform: a framework to monitor the quality of (Governmental) Open Data catalogs, to re-publish improved and linked versions of the datasets and their respective metadata descriptions, and to include the community in the quality improvement process. The information acquired by the linking and (meta)data improvement steps is then integrated in a semantic search engine. In the paper, we first describe the requirements of the platform, which are based on focus group interviews and a web-based survey. Second, we use these requirements to formulate the goals and show the architecture of the overall platform, and third, we showcase the potential and relevance of the platform to resolve the requirements by describing exemplary user journeys exploring the system. The platform is available at: https://www.adequate.at/

    Field Effect Transistors for Terahertz Detection: Physics and First Imaging Applications

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    Resonant frequencies of the two-dimensional plasma in FETs increase with the reduction of the channel dimensions and can reach the THz range for sub-micron gate lengths. Nonlinear properties of the electron plasma in the transistor channel can be used for the detection and mixing of THz frequencies. At cryogenic temperatures resonant and gate voltage tunable detection related to plasma waves resonances, is observed. At room temperature, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector. We present the main theoretical and experimental results on THz detection by FETs in the context of their possible application for THz imaging.Comment: 22 pages, 12 figures, review pape

    Factors influencing the impact of ex-post legislative evaluations:A scoping review

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    This article explores the factors that influence the impact of ex-post legislativeevaluations and suggests that these factors can be divided into three maincategories: context, research quality, and interaction. Contextual factors,including the evaluation’s initiation, it’s place in the legislative process, thevaried functions given by stakeholders, and the level of political or socialattention, are beyond researchers’ control. However, researchers caninfluence research quality and interaction with stakeholders, such as theevaluations’ commissioner, as well as the society at large, thereby increasingthe likelihood of achieving impactful results. They should engage with theevaluation context to improve impact, but must also maintain independencewhile being influenced by the context. These findings are in line with themuch broader literature on the impact of policy and programme evaluationswhich pays less attention to the policy instrument legislation. Therefore, bothdisciplines have an interest in a better exchange of knowledge
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