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IDENTIFYING VULNERABLE LINES CONSIDERING UNCERTAIN HEAT ELECTRIFICATION IN INTEGRATED GAS AND ELECTRICITY NETWORKS
No full textThe installation of heat pumps, powered from clean electricity sources, will play a key role in heat decarbonisation. However, the resulting surge in electricity demand will put the existing transmission lines under enormous strain, increasing the risk of line overloading, potential failure and even loss of load events. This paper presents a probabilistic method for assessing line overload in integrated gas and electricity networks with the consideration of heat electrification. The established model fully considers the uncertainties associated with intermittent generation and fluctuating loads. The effectiveness of the proposed method is verified via its application in an integrated 9-bus electricity and 8-node gas network. Numerical results show that the overload probability of power lines and gas pipelines increases as a result of heat electrification. The overload probability further rises when the correlations of renewable generation and loads are considered, confirming the significance of modelling correlation for an accurate estimation of power and gas flows. The overload probability of some power lines and gas pipelines soar as they become disproportionately loaded, when considering an uneven distribution of heat loads (i.e., clustering of lowcarbon technologies) in the electricity network.<br/
A Bibliometric Mapping Study of the Literature on Oral Health-related Quality of Life
No full textBackgroundOral health is an indispensable component of overall health, and oral health status significantly influences people’s physical, mental, and social well-being. Oral health-related quality of life (OHRQoL), an important and widely used dental patient-reported outcome (dPRO), is attracting more and more researchers’ attention and interest. This study aimed to analyze and map the existing scientific literature regarding OHRQoL through a bibliometric approach, including a summary of the characteristics of OHRQoL-related publications, the identification of prolific entities, high-frequency keywords analysis and research trend analysis via periodic high-impact keywords.MethodsA literature search was conducted in the Web of Science Core Collection to collect OHRQoL-related original research and review articles. After examination and deduplication, the following bibliometric information was extracted from each article: title, abstract, keywords, authors, affiliations, geographic origin (countries/regions), year of publication, journal name, and references. Various scientometric mapping tools including Microsoft Office spreadsheet, VOSviewer, Biblioshiny R-package software, and Scimago Graphica were used to analyze basic bibliometric parameters, leading producers, highimpact keywords, and research trends.ResultsA total of 3324 OHRQoL-related articles (3119 original research articles and 205 review papers) were collected, which received 65704 citations. A total of 9950 authors from 2429 organizations contributed to this body of research. Prolific authors from Europe, USA, Brazil, New Zealand, China, and Canada were identified, and they also centered collaboration clusters in the co-author network. Community Dentistry and Oral Epidemiology was the most prolific journal. Twenty-one keywords with more than 200 occurrences, and 23 keywords with more than 150 occurrences, were identified for publications of 1994-2021 and 2012-2021, respectively. Keyword analysis revealed hot topics such as instrument development and validation, studies targeting children and adolescents, as well as clinical studies in operative dentistry, implantology, orthodontics, and community dentistry. Oral Health Impact Profile is the most commonly used instrument in OHRQoL-related research.ConclusionsOHRQoL is an impactful topic in dental health care as it is not only useful in dental research and patient-centered clinical outcome measures but also provides valuable guidance in dental public health administration and policy making. OHRQoL-related research presents a dynamic landscape and is expected to continue presenting high productivity and broad application in the future
Potentials and Limits of Using Preconfigured Spatial Beams as Bandwidth Resources: Beam Selection vs Beam Aggregation
No full textThis letter studies how to use spatial beams preconfigured in a legacy spatial division multiple access (SDMA) network as bandwidth resources via the implementation of nonorthogonal multiple access (NOMA). Two different beam management schemes, namely beam selection and beam aggregation, are developed to improve the overall system throughput without consuming extra spectrum or changing the performance of the legacy network. Analytical and simulation results are presented to show that the two schemes realize different tradeoffs between system performance and complexity
Acceptability of reducing sedentariness using a mobile-phone application based on ‘if then’ plans for people with psychosis: a focus-group study conducted in the North West of the UK
No full textObjective: To understand the acceptability of (a) reducing sedentary-behaviour in people with psychosis using ‘if-then’ plans and (b) the proposed app content.Design: Qualitative acceptability study. Method: Three structured focus-groups and an interview were conducted with eight participants who had experience of a psychotic episode. They discussed sedentary-behaviour, being more active, critical situations in which they may be tempted to be sedentary and solutions to these (the if-then plans), and a mock-up of the mobile application. The Theoretical Framework of Acceptability (TFA) was used to analyse qualitatively the transcripts.Results: All TFA constructs were coded in each of the transcripts. The idea of reducing sedentary-behaviour was acceptable to people with psychosis, participants knew the importance of being more active, however it is not always their main priority. Likewise, the proposed content of the app was found to be acceptable, with participants already using some of the proposed solutions.Conclusion: This was the first study to use the TFA framework to assess the acceptability of an app that uses critical situations and solutions (“if-then plans”) to help reduce sedentary behaviour for people with psychosis. In this sample (male, English speaking mainly white people), participants understood the benefits of being more active. However, reducing sedentary-behaviour is not the main priority of this population and being sedentary has benefits when their mental-health is bad.<br/
Conversion of glucose to fructose over Sn and Ga-doped zeolite Y in methanol and water media
No full textIn this study, we use zeolite Y as a support for the synthesis of Sn and Ga doped zeolites aimed at the isomerization of glucose to fructose. Though these materials are inactive in water, they are active in methanol and we could ascertain a reaction pathway involving a hydride shift for the interconversion of glucose to fructose and mannose, and a Brønsted acid pathway with the formation of a methyl fructoside intermediate and its hydrolysis to fructose if water was added afterwards. By using characterizations comprising: chemisorption, XPS, XRD, HAADF-STEM and EXAFS; it was possible to demonstrate that a straightforward impregnation protocol for the preparation of our catalysts, led to Sn/Y mainly consisting of small SnO2 clusters on the external surface of the zeolite, whereas Ga/Y consisting of highly dispersed Ga species mostly inside the zeolite pores; and a catalytic activity that appears to be dominated by Brønsted acid sites
Nanoparticle transport within non-Newtonian fluid flow in porous media
No full textControl over dispersion of nanoparticles in polymer solutions through porous media is important for subsurface applications such as soil remediation and enhanced oil recovery. Dispersion is affected by the spatial heterogeneity of porous media, the non-Newtonian behavior of polymer solutions, and the Brownian motion of nanoparticles. Here, we use the Euler-Lagrangian method to simulate the flow of nanoparticles and inelastic non-Newtonian fluids (described by Meter model) in a range of porous media samples and injection rates. In one case, we use a fine mesh of more than 3 million mesh points to model nanoparticles transport in a sandstone sample. The results show that the velocity distribution of nanoparticles in the porous medium is non-Gaussian, which leads to the non-Fickian behaviour of nanoparticles dispersion. Due to pore space confinement, the longtime mean square displacement of nanoparticles depends nonlinearly on time. Additionally the gradient of shear stress in the pore-space of the porous medium dictates the transport behaviour of nanoparticles in the porous medium. Furthermore, the Brownian motion of nanoparticles increases the dispersion of nanoparticles along the longitudinal and transverse direction
Efficient Approximation of Expected Hypervolume Improvement using Gauss-Hermite Quadrature
No full textMany methods for performing multi-objective optimisation of computationally expensive problems have been proposed recently. Typically, a probabilistic surrogate for each objective is constructed from an initial dataset. The surrogates can then be used to produce predictive densities in the objective space for any solution. Using the predictive densities, we can compute the expected hypervolume improvement (EHVI) due to a solution. Maximising the EHVI, we can locate the most promising solution that may be expensively evaluated next. There are closed-form expressions for computing the EHVI, integrating over the multivariate predictive densities. However, they require partitioning the objective space, which can be prohibitively expensive for more than three objectives. Furthermore, there are no closed-form expressions for a problem where the predictive densities are dependent, capturing the correlationsbetween objectives. Monte Carlo approximation is used instead in such cases, which is not cheap. Hence, the need to develop new accurate but cheaper approximation methods remains. Here we investigate an alternative approach toward approximating the EHVI using Gauss-Hermite quadrature.We show that it can be an accurate alternative to Monte Carlo for both independent and correlated predictive densities with statistically signicant rank correlations for a range of popular test problems
SPLITTING HAIRS WITH TRANSCENDENTAL ENTIRE FUNCTIONS
No full textIn recent years, there has been significant progress in the understanding of the dynamics of transcendental entire functions with bounded postsingular set. In particular, for certain classes of such functions, a complete description of their topological dynamics in terms of a simpler model has been given inspired by methods from polynomial dynamics. In this paper, and for the first time, we give analogous results in cases when the postsingular set is unbounded. More specifically, we show that if f is of finite order, has bounded criticality on its Julia set J(f), and its singular set consists of finitely many critical values that escape to infinity and satisfy a certain separation condition, then J(f) is a collection of dynamic rays or hairs, that split at critical points, together with their corresponding landing points. In fact, our result holds for a much larger class of functions with bounded singular set. Moreover, this result is a consequence of a significantly more general one: we provide a topological model for the action of f on its Julia set
The interaction of multiple bubbles in a Hele-Shaw channel
No full textWe study the dynamics of two air bubbles driven by the motion of a suspending viscous fluid in a Hele-Shaw channel with a small elevation along its centreline via physical experiment and numerical simulation of a depth-averagedmodel. For a single-bubble systemwe establish that, in general, bubble propagation speed monotonically increases with bubble volume so that two bubbles of different sizes, in the absence of any hydrodynamic interactions, will either coalesce or separate in a finite time. However our experiments indicate that the bubbles interact and that an unstable two-bubble state is responsible for the eventual dynamical outcome: coalescence or separation. These results motivate us to develop an edge-tracking routine and calculate these weakly unstable two-bubble steady states from the governing equations. The steady states consist of pairs of ‘aligned’ bubbles that appear on the same side of the centreline with the larger bubble leading. We also discover, through time-dependent simulations and physical experiment, another class of two-bubble states that, surprisingly, are stable. In contrast to the ‘aligned’ steady states, these bubbles appear on either side of the centreline and are ‘offset’ from each other. We calculate the bifurcation structures of both classes of steady states as the flow-rate and bubble volume ratio is varied. We find that they exhibit intriguing similarities to the single-bubble bifurcation structure, which has implications for the existence of =-bubble steady states
Should Developing Countries Ban Dual Practice by physicians? An Analysis Under Mixed Hospital Competition*
No full textDual practice, where physicians work both in public and private hospitals, is a widely observed phenomenon, particularly in developing countries. This paper studies a multi-stage game where hospitals compete for physicians as well as patients and, the effort provided by physicians endogenously depends on the competitive setting in which hospitals operate. Specifically, we examine the impact of allowing dual practice on hospital payoffs, physician effort and patients and societal welfare. We find that dual practice introduced in a setting that resembles the characteristics of the health care system of a developing country can be in general socially desirable, since it softens the competition for physician’s exclusive effort (reducing hospital costs) while also increasing the level of their medical effort.<br/