66 research outputs found

    Segregation of Mo atoms into stacking faults in CrFeCoNiMo alloy

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    Solute segregation at dislocations can impede the motion of dislocations, strengthening materials. Here, we study the formation and role of solute segregation at dislocations in CrFeCoNiMo high-entropy alloys (HEAs) by high-angle annular dark-field scanning transmission electron microscopy imaging and mechanical testing both deformed and annealed samples. Mo atoms exhibit pronounced segregation into the planar-extended core of dislocations, i.e. stacking faults, causing the increase in the yield strength while the loss of the ductility. This work suggests that mechanical properties of HEAs can be tailored by alloying additional elements that are in favor of segregation into dislocations

    Enterococcus faecium

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    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Moving from fragmented to seamless sense-making in blended learning

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    Context: Sense-making, understood as meaning making or giving meaning to experience, is an integral part of everyday life, work and learning, and is a process critical in enabling people to recognise how and when to respond to situations appropriately so that they can resolve problems effectively (Weick et al., 2005). Earlier studies on sense-making in educational or organizational settings (e.g. Harverly et al., 2020; Weick et al., 2005) tended to focus on the sense-making process per se in particular setting such as classrooms or organizations, few of them have paid much attention to the sense-making process in blended learning (BL). BL in vocational training mainly aims to enable adult learners to apply what was learnt in classrooms to solve authentic problems in workplaces or simulated settings. High quality of sense-making is crucial to help the learners achieve the aim. This timely study is to offer a comparative look at how different dynamics of BL interplay together to mediate the quality of sense-making in achieving learning outcomes. The dynamics include industry and training connections, policy and institutional contexts, the inhabited pedagogical practices and curriculum design. Methods: This study adopted phenomenological (Moran, 2000) and semi-ethnographic approaches (Hammersley, 2010), including semi-structured interviews, observations, analysis of relevant documents (e.g. curriculum and learning materials) to capture the rich data in case studies to understand learners’ sense-making experience in BL. Researchers focused on seeking to understand how different environments, tools and artefacts mediate the quality of sense-making as the learners progressed through their learning journey. To triangulate the data, adult educators, curriculum designers and where possible, workplace supervisors, were also interviewed and observed for their perceptions and behaviours in learners’ sense-making in BL. Findings: The findings from two different BL courses (ICT and HR) surface that the degree to which learners’ sense-making is fragmented (low quality) or seamless (high quality) is mediated by the interplay of different contextual factors in BL in multiple ways, such as, the connections (or not) with industry, the use (or not) of authentic problems and tasks. Conclusion: The interplay between different dynamics in BL is of great importance to mediate the curriculum design and pedagogical approaches used in BL for high quality of sense-making of adult learners in vocational training. (DIPF/Orig.

    Segregation of Mo atoms into stacking faults in CrFeCoNiMo alloy

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    Solute segregation at dislocations can impede the motion of dislocations, strengthening materials. Here, we study the formation and role of solute segregation at dislocations in CrFeCoNiMo high-entropy alloys (HEAs) by high-angle annular dark-field scanning transmission electron microscopy imaging and mechanical testing both deformed and annealed samples. Mo atoms exhibit pronounced segregation into the planar-extended core of dislocations, i.e. stacking faults, causing the increase in the yield strength while the loss of the ductility. This work suggests that mechanical properties of HEAs can be tailored by alloying additional elements that are in favor of segregation into dislocations

    Fe/Co-based Bimetallic MOF-derived Co3Fe7@NCNTFs Bifunctional Electrocatalyst for High-Efficiency Overall Water Splitting

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    © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Electrocatalytic water splitting to produce hydrogen and oxygen is regarded as one of the most promising methods to generate clean and sustainable energy for replacing fossil fuels. However, the design and development of an efficient bifunctional catalyst for simultaneous generation of hydrogen and oxygen remains extremely challenging yet is critical for the practical implementation of water electrolysis. Here, we report a facile method to fabricate novel N-doped carbon nanotube frameworks (NCNTFs) by the pyrolysis of a bimetallic metal organic framework (MIL-88-Fe/Co). The resultant electrocatalyst, Co3Fe7@NCNTFs, exhibits excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm2 at a low overpotential of just 264 mV in 1 M KOH solution, and 197 mV for the hydrogen evolution reaction. The high electrocatalytic activity arises from the synergistic effect between the chemistry of the Co3Fe7 and the NCNTs coupled to the novel framework structure. The remarkable electrocatalytic performance of our bifunctional electrocatalyst provides a promising pathway to high-performance overall water splitting and electrochemical energy devices
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