Development and Persistence of 'Static' or 'Dead' Zones in Flows

Certain ceramic products are formed through extrusion processes, where a slurry is forced through small openings to form such products as filters. At the top is a large tank. The slurry is forced through the tank into an extrusion chamber, and then out through slots to form the finished product. [The slurry may be thought of as a mixture of clay (or other polymers), water, and other binders. There are many ways to model this mixture, some of which will be discussed in this report. For instance, the slurry can be modeled as a non-Newtonian fluid, a two-phase flow with liquid and solids, or a viscoelastic fluid. One can also model the mixture as an elongated particle suspension in water, where changes in the orientation of the particles could affect the flow.] After the extrusion process is complete, one finds that ‘dead zones’ of dry paste accumulate in two areas. Most prominently, they occur at the lower corners of the tank. They also occur on the floor of the extrusion chamber near the slots, both near and away from the walls. Since we will consider wall effects in the tank, for the extrusion chamber we consider only flow cells sufficiently far away from the walls. Then we may exploit the periodic nature of the device and consider only a single flow cell. The aim of this project is to determine the formation mechanisms of these dead zones, and see how they affect the overall flow

Effectiveness and cost-effectiveness of a telehealth intervention to support the management of long-term conditions:study protocol for two linked randomized controlled trials

As the population ages, more people are suffering from long-term health conditions (LTCs). Health services around the world are exploring new ways of supporting people with LTCs and there is great interest in the use of telehealth: technologies such as the Internet, telephone and home self-monitoring

Observations of Long-tailed Weasel, Mustela frenata, Hunting Behavior in Central West Virginia

Using infrared video-surveillance systems during 1999–2000, we observed attempts by two individual Long-tailed Weasels (Mustela frenata) to depredate female Ruffed Grouse (Bonasa umbellus) and their clutch of eggs. Neither female was captured despite Long-tailed Weasel attacks on multiple nights, but all eggs from one nest were either consumed or cached over a two-night period. Although Long-tailed Weasels have been shown to return quickly to areas of abundant prey, return visit behavior to locations where weasels were unsuccessful or only partially successful are poorly described

Observations of Long-tailed Weasel, Mustela frenata, Hunting Behavior in Central West Virginia

Using infrared video-surveillance systems during 1999–2000, we observed attempts by two individual Long-tailed Weasels (Mustela frenata) to depredate female Ruffed Grouse (Bonasa umbellus) and their clutch of eggs. Neither female was captured despite Long-tailed Weasel attacks on multiple nights, but all eggs from one nest were either consumed or cached over a two-night period. Although Long-tailed Weasels have been shown to return quickly to areas of abundant prey, return visit behavior to locations where weasels were unsuccessful or only partially successful are poorly described

‘Most people have no idea what autism is’ : Unpacking autism disclosure using social media analysis

Autism disclosure can be a complicated decision that autistic people experience. Positive outcomes can include feelings of acceptance and support, but negative outcomes can include stigma and discrimination. Although a surge in research on this topic has led to more understanding around autism disclosure, the methodologies used may have limited who was contributing to the conversation and data. To overcome this, we analyzed 3 years (2020−2022) of social media data (Reddit and Twitter) as this was public information that did not rely on researcher data collection. Reflexive thematic analysis of 3121 posts led to the generation of four themes: People do not understand autism (with experiences related to employment, dating, healthcare and mental health), autistic people just want privacy and respect, autistic people can lead us forward and non-autistic people need to assume more responsibility. We discuss how autistic adults experience the impact of society’s lack of understanding of autism on a daily basis whether they disclose or not, and that it is everybody’s responsibility to challenge negative stereotypes and promote a more inclusive society

e-Social Science and Evidence-Based Policy Assessment : Challenges and Solutions

Peer reviewedPreprin

Structure and stability of steady porous medium convection at large Rayleigh number

A systematic investigation of unstable steady-state solutions of the Darcy–Oberbeck–Boussinesq equations at large values of the Rayleigh number Ra is performed to gain insight into two-dimensional porous medium convection in domains of varying aspect-ratio L. The steady convective states are shown to transport less heat than the statistically steady ‘turbulent’ flow realised at the same parameter values: the Nusselt number Nu∼Ra for turbulent porous medium convection, while Nu∼Ra 0.6 for the maximum heat-transporting steady solutions. A key finding is that the lateral scale of the heat-flux-maximising solutions shrinks roughly as L∼Ra−0.5, reminiscent of the decrease of the mean inter-plume spacing observed in turbulent porous medium convection as the thermal forcing is increased. A spatial Floquet analysis is performed to investigate the linear stability of the fully nonlinear steady convective states, extending a recent study by Hewitt et al. (J. Fluid Mech.737, 2013) by treating a base convective state – and secondary stability modes – that satisfy appropriate boundary conditions along plane parallel walls. As in that study, a bulk instability mode is found for sufficiently small aspect-ratio base states. However, the growth rate of this bulk mode is shown to be significantly reduced by the presence of the walls. Beyond a certain critical Ra-dependent aspect-ratio, the base state is most strongly unstable to a secondary mode that is localised near the heated and cooled walls. Direct numerical simulations, strategically initialised to investigate the fully nonlinear evolution of the most dangerous secondary instability modes, suggest that the (long time) mean inter-plume spacing in statistically-steady porous medium convection results from a balance between the competing effects of these two types of instability

Exploring uncertainty of trends in the North Pacific Jet position

It has been difficult to establish trends in the observed jet streams, despite modelling studies suggesting they will move polewards in a warming world. While this is partly due to biases between the models and observations, we propose that another uncertainty is rooted in the choice of statistic used to determine the 'jet latitude', one measure used to quantify the jet position. We use seven different jet latitude statistics, four climate reanalysis products, and CMIP6 simulations to assess the relative importance of different uncertainties associated with lower-tropospheric North Pacific Jet (NPJ) trends. Our results show a statistically significant poleward trend in the observed winter NPJ across all reanalyses and using all jet latitude statistics. The magnitude of this trend is most sensitive to the choice of statistic. Furthermore, we find that the NPJ shifts poleward in Autumn under high emission scenarios, which is robust to the choice of jet statistic