267 research outputs found

    Water and energy systems in sustainable city development: a case of Sub-saharan Africa

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    Current urban water and energy systems are expanding while increasing attention is paid to their social, economic and environmental impacts. As a research contribution that can support real-world decision making and transitions to sustainable cities and communities, we have built a model-based and data-driven platform combining comprehensive database, agent-based simulation and resource technology network optimization for system level water and energy planning. Several use cases are demonstrated based on the Greater Accra Metropolitan Area (GAMA) city-region in Ghana, as part of the Future Cities Africa (FCA) project. The outputs depict an overall resource landscape of the studied urban area, but also provide the energy, water, and other resource balance of supply and demand from both macro and micro perspectives, which is used to propose environmental friendly and cost effective sustainable city development strategies. This work is to become a core component of the resilience.io platform as an open-source integrated systematic tool gathering social, environmental and economic data to inform urban planning, investment and policy-making for city-regions globally

    Comparison of microscopic and macroscopic instabilities in a class of two-dimensional periodic composites

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    O in the present work is the quantitative comparison between the microscopic and the corresponding macroscopic failure in a two-dimensional elastic medium with known periodic microstructure. This comparison establishes theoretical limits for the validity for the averaged (homogenized) response of microstructured elastic media. Attention is focussed on an approximation of a fiber reinforced composite modeled as an infinite periodic grillage of axially compressed beams with an average shear stiffness. The particular beam model was chosen so that the problem would be analytically tractable, yet of sufficient complexity to exhibit nontrivial microscopic and macroscopic failure modes.A comparison of the stresses at the onset of the microscopic failure (taken to be the first bifurcation away from the principal periodic solution) to the stresses at the onset of the macroscopic failure (which corresponds to the loss of ellipticity for the incremental response of the homogenized model) allows one to identify whether the first failure mode, also termed the critical mode, is local (microscopic) or global (macroscopic) in nature. An extensive investigation of the influence of various model parameters on the failure modes of the composite has been undertaken. The results obtained show the importance of the interstitial stiffness in deciding the nature of the critical mode. The presentation is concluded by a discussion of the results with suggestions for future work.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30623/1/0000264.pd

    Membrane Spin Up in a Normal Gravity Field: Experiments and Simulations

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    Finite element simulations and experimental observations of the spin up in vacuum of a thin membrane loaded by gravity are presented. The numerical techniques take into account the run time of each simulation and energy convergence; it is shown that accurate results can be obtained quite quickly in a rotating reference frame, and that including stiffness-proportional material damping helps convergence of the integration. It is also found that a very fine finite element mesh around the hub of the membrane is required to obtain consistent results. The experimental setup allows spinning of the membrane in a vacuum box; a measurement technique that uses stereo Digital Image Correlation is presented. A comparison between experiments and simulations using characteristic parameters of the shape of a membrane, i.e. the number of rotational symmetric waves, the average deflection, and the elastic bending strain energy of the membrane, shows good agreement between experiments and simulations

    Creating connections - the development of a mobile-health monitoring system for heart failure:Qualitative findings from a usability cohort study

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    Objective There is significant interest in the role of digital health technology in enabling optimal monitoring of heart failure patients. To harness this potential, it is vital to account for users’ capacity and preferences in the development of technological solutions. We adopted an iterative approach focussed on learning from users’ interactions with a mobile-health monitoring system.Methods We used a participatory mixed methods research approach to develop and evaluate a mobile-health monitoring system. Fifty-eight heart failure patients were recruited from three health care settings in the UK and provided with Internet-enabled tablet computers that were wirelessly linked to sensor devices for blood pressure, heart rate and weight monitoring. One to two home visits were conducted with a subgroup of 29 participants to evaluate the usability of the system over a median follow-up period of six months. The thematic analysis of observational data and 45 interviews was informed by the domestication of technology theory.Results Our findings indicate that digital health technologies need to create and extend connections with health professionals, be incorporated into users’ daily routines, and be personalised according to users’ technological competencies and interest in assuming a proactive or more passive role in monitoring their condition.Conclusions Users' patterns of engagement with health technology changes over time and varies according to their need and capacity to use the technology. Incorporating diverse user experiences in the development and maintenance of mobile-health systems is likely to increase the extent of successful uptake and impacts on outcomes for patients and providers.%U http://dhj.sagepub.com/content/spdhj/2/2055207616671461.full.pd

    Medium-chain triglycerides may improve memory in non-demented older adults: a systematic review of randomized controlled trials

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    Background: Ketosis has been exploited for its neuroprotective impact and treatment of neurological conditions via ketone production. Exogenous medium-chain triglyceride (MCT) supplementation may induce nutritional ketosis. The aim of this systematic review is to explore the effects of MCTs on memory function in older adults without cognitive impairment. Methods: A systematic literature search of PubMed, Cochrane Library, Scopus, and Web of Science was employed from inception until April 2022 for randomized controlled trials (RCTs) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, investigating the impact of MCT oils on components of memory. Risk of bias (RoB2) tool was utilized for quality assessment. Results: Six trials were included for qualitative synthesis, in which two studies examined the effect of MCTs through a ketogenic meal. MCT supplementation compared to controls was associated with improved indices of memory function in 4 out of 6 studies, particularly working memory. A meta-analysis was not employed due to the low number of studies, therefore, a true effect measure of MCT supplementation was not explored. Conclusions: MCT supplementation may enhance working memory in non-demented older adults. These effects may be more prominent in individuals with lower baseline scores, from short and long-term supplementation. Further studies are warranted to confirm these findings in terms of optimal dose and MCTs composition, which may protect from memory decline during aging

    Onset of entanglement

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    We have developed a theory of polymer entanglement using an extended Cahn-Hilliard functional, with two extra terms. One is a nonlocal attractive term, operating over mesoscales, which is interpreted as giving rise to entanglement, and the other a local repulsive term indicative of excluded volume interactions. We show how such a functional can be derived using notions from gauge theory. We go beyond the Gaussian approximation, to the one-loop level, to show that the system exhibits a crossover to a state of entanglement as the average chain length between points of entanglement decreases. This crossover is marked by critical slowing down, as the effective diffusion constant goes to zero. We have also computed the tensile modulus of the system, and we find a corresponding crossover to a regime of high modulus.Comment: 18 pages, with 4 figure

    Light4Health eLearning Course: health research for interior lighting design. Re-thinking design approaches based on science

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    This paper presents the results of \u27Light4Health\u27 (L4H), a three-year EU Erasmus+ Strategic Partnership grant project (2019-2021), which investigated, systematized and taught health-related research on the impact of natural and artificial light on human health and well-being relevant to indoor lighting design. The objective was to re-think evidence-based lighting design approaches for residential, working/educational, and healthcare spaces, in order to develop a novel cross-disciplinary eLearning platform, that intersects lighting design and current peer-reviewed health research through a select combination of the most relevant research, methods, and tools. The content was developed through teaching workshops with international researchers, teachers, and students. Participating students were introduced to the application of relevant research and new metrics, in order to produce creative lighting design proposals. Students were able to inform lighting design approaches that support health and well-being without compromising creativity via the tools and methods developed through the health sciences. With this project, participants and consortium members have narrowed the gap that exists between research and the practice/application of lighting, by translating research from complex scientific jargon into various tools for designers to use. The knowledge gained, was consolidated into an open-access online curriculum for international lighting design students, educators and professionals via the free eLearning Moodle platform (https://course.light4health.net/)
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