298 research outputs found

    Elucidating lithium-ion and proton dynamics in anti-perovskite solid electrolytes

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    All-solid-state Li-ion batteries are currently attracting considerable research attention as they present a viable opportunity for increased energy density and safety when compared to conventional liquid electrolyte-based devices. The Li-rich anti-perovskite Li3−xOHxCl has generated recent interest as a potential solid electrolyte material, but its lithium and proton transport capabilities as a function of composition are not fully characterised. In this work, we apply a combination of ab initio molecular dynamics and 1H, 2H and 7Li solid-state NMR spectroscopy to study the mobility of lithium ions and protons in Li3−xOHxCl. Our calculations predict a strongly exothermic hydration enthalpy for Li3OCl, which explains the ease with which this material absorbs moisture and the difficulty in synthesising moisture-free samples. We show that the activation energy for Li-ion conduction increases with increasing proton content. The atomistic simulations indicate fast Li-ion diffusion but rule out the contribution of long-range proton diffusion. These findings are supported by variable-temperature solid-state NMR experiments, which indicate localised proton motion and long-range Li-ion mobility that are intimately connected. Our findings confirm that Li3−xOHxCl is a promising solid electrolyte material for all-solid-state Li-ion batteries

    Time-Fractional KdV Equation: Formulation and Solution using Variational Methods

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    In this work, the semi-inverse method has been used to derive the Lagrangian of the Korteweg-de Vries (KdV) equation. Then, the time operator of the Lagrangian of the KdV equation has been transformed into fractional domain in terms of the left-Riemann-Liouville fractional differential operator. The variational of the functional of this Lagrangian leads neatly to Euler-Lagrange equation. Via Agrawal's method, one can easily derive the time-fractional KdV equation from this Euler-Lagrange equation. Remarkably, the time-fractional term in the resulting KdV equation is obtained in Riesz fractional derivative in a direct manner. As a second step, the derived time-fractional KdV equation is solved using He's variational-iteration method. The calculations are carried out using initial condition depends on the nonlinear and dispersion coefficients of the KdV equation. We remark that more pronounced effects and deeper insight into the formation and properties of the resulting solitary wave by additionally considering the fractional order derivative beside the nonlinearity and dispersion terms.Comment: The paper has been rewritten, 12 pages, 3 figure

    Hereditary risk factors for the development of gastric cancer in younger patients

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    BACKGROUND: It is believed that the development of gastric cancer (GC) before the age of 50 has a hereditary basis. Blood group A and history of gastric cancer in first-degree relatives have been shown to be risk factors for GC. METHODS: In this case-control study, we enrolled patients with GC who were diagnosed before the age of 50. Patients who were diagnosed as having GC were selected. A total of 534 cases were found; of these, 44 diagnosed before the age of 50 were included in the case group. For the control group, 22 males and 22 females were randomly selected from the remaining subjects, who had diagnoses of GC after the age of 50. All the surviving patients and family members of the dead patients were interviewed about the history of cancer in the family and the age at which other family members developed cancer. The blood group of each subject was also obtained. RESULTS: forty-four cases under 50 years old (mean age: 36.2 years) and forty-four controls (mean age: 67.1 years) were enrolled in the study. At the time of the study, 59.1% of the study group and 50% of the control group were alive (P value = NS). In the study group, 68.1%, 13.6%, 13.6% and 4.5% had blood groups O, A, B and AB, respectively. In the control group the corresponding figures were 27.7%, 63.6%, 6.8% and 4.5%. First or second-degree relatives with cancer, including gastric (the most frequent), breast, lung, gynecological and hematological malignancies, were noted in 54.5% of the cases and 11.4% of the controls (p < 0.01). Family histories of cancer were accepted as valid provided that they were based on valid medical documents. CONCLUSIONS: It seems that the development of GC before the age of 50 is likely to be accompanied by familial susceptibility. Interestingly, our study showed a significant correlation between blood group O and the development of gastric cancer under the age of 50

    Householders’ Mental Models of Domestic Energy Consumption: Using a Sort-And-Cluster Method to Identify Shared Concepts of Appliance Similarity

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    If in-home displays and other interventions are to successfully influence people's energy consumption, they need to communicate about energy in terms that make sense to users. Here we explore householders' perceptions of energy consumption, using a novel combination of card-sorting and clustering to reveal shared patterns in the way people think about domestic energy consumption. The data suggest that, when participants were asked to group appliances which they felt naturally 'went together', there are relatively few shared ideas about which appliances are conceptually related. To the extent participants agreed on which appliances belonged together, these groupings were based on activities (e.g., entertainment) and location within the home (e.g., kitchen); energy consumption was not an important factor in people's categorisations. This suggests messages about behaviour change aimed at reducing energy consumption might better be tied to social practices than to consumption itself

    Climate change and climate variability: personal motivation for adaptation and mitigation

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    BACKGROUND: Global climate change impacts on human and natural systems are predicted to be severe, far reaching, and to affect the most physically and economically vulnerable disproportionately. Society can respond to these threats through two strategies: mitigation and adaptation. Industry, commerce, and government play indispensable roles in these actions but so do individuals, if they are receptive to behavior change. We explored whether the health frame can be used as a context to motivate behavioral reductions of greenhouse gas emissions and adaptation measures. METHODS: In 2008, we conducted a cross-sectional survey in the United States using random digit dialing. Personal relevance of climate change from health threats was explored with the Health Belief Model (HBM) as a conceptual frame and analyzed through logistic regressions and path analysis. RESULTS: Of 771 individuals surveyed, 81% (n = 622) acknowledged that climate change was occurring, and were aware of the associated ecologic and human health risks. Respondents reported reduced energy consumption if they believed climate change could affect their way of life (perceived susceptibility), Odds Ratio (OR) = 2.4 (95% Confidence Interval (CI): 1.4-4.0), endanger their life (perceived severity), OR = 1.9 (95% CI: 1.1-3.1), or saw serious barriers to protecting themselves from climate change, OR = 2.1 (95% CI: 1.2-3.5). Perceived susceptibility had the strongest effect on reduced energy consumption, either directly or indirectly via perceived severity. Those that reported having the necessary information to prepare for climate change impacts were more likely to have an emergency kit OR = 2.1 (95% CI: 1.4-3.1) or plan, OR = 2.2 (95% CI: 1.5-3.2) for their household, but also saw serious barriers to protecting themselves from climate change or climate variability, either by having an emergency kit OR = 1.6 (95% CI: 1.1-2.4) or an emergency plan OR = 1.5 (95%CI: 1.0-2.2). CONCLUSIONS: Motivation for voluntary mitigation is mostly dependent on perceived susceptibility to threats and severity of climate change or climate variability impacts, whereas adaptation is largely dependent on the availability of information relevant to climate change. Thus, the climate change discourse could be framed from a health perspective to motivate behaviour change
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