Dynamics of rate-based separation methods for granular materials and the solid-liquid interaction

Processing of granular materials is a costly endeavor that spans across a variety of industries ranging from pharmaceutical, food, and cosmetics to construction and metal extraction. Devices commonly used in granular processing however, lack a fundamental understanding of granular behavior - implementing outdated technologies based on heuristics. Separation units for dry mixture, in particular, are highly energy intensive and environmentally unfriendly. For wet or damp mixtures, less is understood about the liquid-solid particle interactions that govern mixture behavior, which has limited development of advanced separation units for wet mixtures in industry. The work herein implements discrete element method (DEM) simulations along with experimental work to present two energy-efficient (green), granular separation unit prototypes, designed to rationally exploit the properties of particulate materials that naturally result in segregation. This work also describes an analytical method that yielded a deeper and novel characterization of solid-liquid interactions among two- or three-particles simultaneously. Taken together, the work presented in this dissertation seeks to advance the current state of knowledge of solid-solid and solid-liquid interactions, and has furthered the development of rationale separation systems with applications in industry. Herein, segregation of granular mixtures with two newly developed systems was successfully demonstrated. Each prototype potentiates the effects of physical differences among particles to achieve separation via a kinetic differential, known as rate-based separation. In the first case, a passive separation system – analogous to sieving – was developed to successfully induce segregation among size-disperse granular mixtures, without being encumbered by issues with material accumulation or fouling. In the second case, separation of density-disperse mixtures was successfully demonstrated using a fluid coated vibrating system. The unique features of these systems make each an attractive option for further development as a unit operation in manufacturing settings, particularly given the rising interest in green technology. Further study of the rupture forces of complex liquid bridges is presented to advance the understanding of liquid-solid interactions in particle processing. Using a custom-built micromechanical force microscope, the rupture force of bridges conjoining two or three particles were analytically measured. Direct characterization of three-particle interactions in the funicular regime is a novel achievement. Results indicate that the maximum force and rupture distance are the effect of surface characteristics, straining mechanism and effective liquid volume. These insights may encourage new solutions to achieve wet mixture separation. This work utilizes powerful computational simulations and experimental methods to reveal novel insights of granular behavior, which drive innovation of new, rational separation devices that are attractive to industry applications

Steel heat treating: Mathematical modelling and numerical simulation of a problem arising in the automotive industry

We describe a mathematical model for the industrial heating and cooling processes of a steel workpiece representing the steering rack of an automobile. The goal of steel heat treating is to provide a hardened surface on critical parts of the workpiece while keeping the rest soft and ductile in order to reduce fatigue. The high hardness is due to the phase transformation of steel accompanying the rapid cooling. This work takes into account both heating-cooling stage and viscoplastic model. Once the general mathematical formulation is derived, we can perform some numerical simulations

Measuring the built environment in studies of child health – a meta-narrative review of associations

Although the built environment (BE) is important for children’s health there is little consensus about which features are most important due to differences in measurement and outcomes across disciplines. This meta-narrative re-view was undertaken by a multi-disciplinary team of researchers to summarise ways in which BE are measured, and how these link to children’s health. A structured search of four databases across the relevant disciplines retrieved 108 relevant references. The health-related outcomes most commonly addressed were active travel, physical activ-ity and play, and obesity. Many studies used objective (GIS and street audits) or standardised subjective (per-ceived), measurements of the built environment. However, there was a wide variety, and sometimes inconsistency, in their use. There were clear associations between the BE and health. Objective physical activity and self-reported active travel were positively associated with higher street connectivity or walkability measures; while self-reported physical activity and play had the strongest association with reduced street connectivity, indicated by quieter, one-way streets. Future research should implement consistent BE measures to ensure key features are explored. A systems approach will be particularly relevant for addressing place-based health inequalities, given potential un-intended health consequences of making changes to the built environment

The liveable cities method:establishing the case for transformative change for a UK metro

There is currently great interest in the creation of sustainable and liveable cities, both in the UK and globally. While it can be argued that good progress is being made in thinking about the needs of future cities, meeting these needs and aspirations in practice poses major challenges of understanding and measurement (what is meant by these terms and how can progress towards their achievement be measured?), complexity (cities are complex systems of systems with many interacting parts) and resilience (will interventions made today be relevant and effective in the future?). The Liveable Cities research programme created a systematic decision-making method for improving urban sustainability and liveability: the Liveable Cities Method (LCM). The LCM prioritises four criteria – individual and societal well-being, resource security, resource efficiency and carbon dioxide emissions as a proxy for environmental harm – in an interconnected framework and assesses the need for, and the resilience of, interventions designed to move cities towards improved sustainability and liveability. This paper illustrates the LCM through an example intervention made to the city of Birmingham, UK, and highlights how addressing sustainability and liveability in this way offers unique opportunities for the UK civil engineering profession to lead thinking among urban professionals

Achieving robustness to aleatoric uncertainty with heteroscedastic Bayesian optimisation

Bayesian optimisation is a sample-efficient search methodology that holds great promise for accelerating drug and materials discovery programs. A frequently-overlooked modelling consideration in Bayesian optimisation strategies however, is the representation of heteroscedastic aleatoric uncertainty. In many practical applications it is desirable to identify inputs with low aleatoric noise, an example of which might be a material composition which consistently displays robust properties in response to a noisy fabrication process. In this paper, we propose a heteroscedastic Bayesian optimisation scheme capable of representing and minimising aleatoric noise across the input space. Our scheme employs a heteroscedastic Gaussian process (GP) surrogate model in conjunction with two straightforward adaptations of existing acquisition functions. First, we extend the augmented expected improvement (AEI) heuristic to the heteroscedastic setting and second, we introduce the aleatoric noise-penalised expected improvement (ANPEI) heuristic. Both methodologies are capable of penalising aleatoric noise in the suggestions and yield improved performance relative to homoscedastic Bayesian optimisation and random sampling on toy problems as well as on two real-world scientific datasets. Code is available at: \url{https://github.com/Ryan-Rhys/Heteroscedastic-BO

Evidence for protein-mediated fatty acid efflux by adipocytes

Abstract Aim: The hormonally controlled mobilization and release of fatty acids from adipocytes into the circulation is an important physiological process required for energy homeostasis. While uptake of fatty acids by adipocytes has been suggested to be predominantly protein-mediated, it is unclear whether the efflux of fatty acids also requires membrane proteins. Methods: We used fluorescent fatty acid efflux assays and colorimetric assays for free fatty acids and glycerol to identify inhibitors with effects on fatty acid efflux, but not lipolysis, in 3T3-L1 adipocytes. We assessed the effect of these inhibitors on a fibroblast-based cell line expressing fatty acid transport protein 1, hormone-sensitive lipase and perilipin, which presumably lacks adipocyte-specific proteins for fatty acid efflux. Results: We identified 4,4¢-diisothiocyanatostilbene-2,2¢-disulfonic acid (DIDS) as an inhibitor of fatty acid efflux that did not impair lipolysis or the cellular exit of glycerol but lead to an accumulation of intracellular fatty acids. In contrast, fatty acid efflux by the reconstituted cellular model for fatty acid efflux was responsive to lipolytic stimuli, but insensitive to DIDS inhibition. Conclusion: We propose that adipocytes specifically express an as yet unidentified DIDS-sensitive protein that enhances the efflux of fatty acids and therefore may lead to novel treatment approaches for obesity-related disorders characterized by abnormal lipid fluxes and ectopic triglyceride accumulation

What are the priorities for prevention and control of non-communicable diseases and injuries in sub-Saharan Africa and South East Asia?

Last year’s UN high level meeting sought to galvanise the international community into scaling up its response to the escalating global burden of non-communicable diseases. With resources tight, D Chisholm and colleagues examine which interventions should be given priority for action and investmen

How sharing can contribute to more sustainable cities

\ua9 2017 by the authors. Recently, much of the literature on sharing in cities has focused on the sharing economy, in which people use online platforms to share underutilized assets in the marketplace. This view of sharing is too narrow for cities, as it neglects the myriad of ways, reasons, and scales in which citizens share in urban environments. Research presented here by the Liveable Cities team in the form of participant workshops in Lancaster and Birmingham, UK, suggests that a broader approach to understanding sharing in cities is essential. The research also highlighted tools and methods that may be used to help to identify sharing in communities. The paper ends with advice to city stakeholders, such as policymakers, urban planners, and urban designers, who are considering how to enhance sustainability in cities through sharing

Cost-effectiveness analysis of guidelines for antihypertensive care in Finland

<p>Abstract</p> <p>Background</p> <p>Hypertension is one of the major causes of disease burden affecting the Finnish population. Over the last decade, evidence-based care has emerged to complement other approaches to antihypertensive care, often without health economic assessment of its costs and effects. This study looks at the extent to which changes proposed by the 2002 Finnish evidence-based Current Care Guidelines concerning the prevention, diagnosis, and treatment of hypertension (the ACCG scenario) can be considered cost-effective when compared to modelled prior clinical practice (the PCP scenario).</p> <p>Methods</p> <p>A decision analytic model compares the ACCG and PCP scenarios using information synthesised from a set of national registers covering prescription drug reimbursements, morbidity, and mortality with data from two national surveys concerning health and functional capacity. Statistical methods are used to estimate model parameters from Finnish data. We model the potential impact of the different treatment strategies under the ACCG and PCP scenarios, such as lifestyle counselling and drug therapy, for subgroups stratified by age, gender, and blood pressure. The model provides estimates of the differences in major health-related outcomes in the form of life-years and costs as calculated from a 'public health care system' perspective. Cost-effectiveness analysis results are presented for subgroups and for the target population as a whole.</p> <p>Results</p> <p>The impact of the use of the ACCG scenario in subgroups (aged 40–80) without concomitant cardiovascular and related diseases is mainly positive. Generally, costs and life-years decrease in unison in the lowest blood pressure group, while in the highest blood pressure group costs and life-years increase together and in the other groups the ACCG scenario is less expensive and produces more life-years. When the costs and effects for subgroups are combined using standard decision analytic aggregation methods, the ACCG scenario is cost-saving and more effective.</p> <p>Conclusion</p> <p>The ACCG scenario is likely to reduce costs and increase life-years compared to the PCP scenario in many subgroups. If the estimated trade-offs between the subgroups in terms of outcomes and costs are acceptable to decision-makers, then widespread implementation of the ACCG scenario is expected to reduce overall costs and be accompanied by positive outcomes overall.</p