14 research outputs found

    Comprehensive comparison of pore-scale models for multiphase flow in porous media

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    Multiphase flows in porous media are important in many natural and industrial processes. Pore-scale models for multiphase flows have seen rapid development in recent years and are becoming increasingly useful as predictive tools in both academic and industrial applications. However, quantitative comparisons between different pore-scale models, and between these models and experimental data, are lacking. Here, we perform an objective comparison of a variety of state-of-the-art pore-scale models, including lattice Boltzmann, stochastic rotation dynamics, volume-of-fluid, level-set, phase-field, and pore-network models. As the basis for this comparison, we use a dataset from recent microfluidic experiments with precisely controlled pore geometry and wettability conditions, which offers an unprecedented benchmarking opportunity. We compare the results of the 14 participating teams both qualitatively and quantitatively using several standard metrics, such as fractal dimension, finger width, and displacement efficiency. We find that no single method excels across all conditions and that thin films and corner flow present substantial modeling and computational challenges

    Support needs of patients with obesity in primary care: A practice-list survey

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    © 2018 The Author(s). Background: UK guidelines recommend that patients with obesity in primary care receive opportunistic weight loss advice from health care professionals, but there is a lack of research into the characteristics and existing weight management practices of these patients. The aim of this study was to characterise primary care patients with obesity in England, to inform the screening, support, and referral options appropriate to this group. Methods: We surveyed 1309 patients registered at 15 GP practices in North East England, aged =18 years and with objectively recorded obesity (BMI = 30 kg/m 2 ). Study participants reported their weight history, health status, past and current weight loss activities, motivating factors, weight loss strategies used, professional support received, and perceived barriers to weight loss. Results: 62% of participants were actively trying to lose weight, and a further 15% ha d attempted and discontinued weight loss in the last 12 months. Only 20% of the sample had sought GP support for weight loss in the last 12 months; instead, most efforts to lose weight were self-guided and did not use evidence-based strategies. Those who sought GP weight loss support were likely to use it and find it motivating. Participants had attempted weight loss on multiple previous occasions and overall felt less confident and successful at maintaining weight loss than losing it. Participants at greatest clinical risk (higher BMI and more health conditions) reported particularly low confidence and multiple barriers to weight loss, but were nevertheless highly motivated to lose weight and keep it off. Conclusions: We identified the need for informational, structural, and weight loss maintenance-specific support for GP patients with objectively-recorded obesity. Study participants were motivated to lose weight and keep it off, but lacked the confidence and understanding of effective strategies required to do this. GP weight loss support was acceptable and useful but underutilised, indicating that screening and brief referral interventions to structured programmes may augment patients' current weight management activities and meet key support needs whilst optimising limited primary care resources
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