The Mechanism behind Erosive Bursts in Porous Media

Erosion and deposition during flow through porous media can lead to large erosive bursts that manifest as jumps in permeability and pressure loss. Here we reveal that the cause of these bursts is the re-opening of clogged pores when the pressure difference between two opposite sites of the pore surpasses a certain threshold. We perform numerical simulations of flow through porous media and compare our predictions to experimental results, recovering with excellent agreement shape and power-law distribution of pressure loss jumps, and the behavior of the permeability jumps as function of particle concentration. Furthermore, we find that erosive bursts only occur for pressure gradient thresholds within the range of two critical values, independent on how the flow is driven. Our findings provide a better understanding of sudden sand production in oil wells and breakthrough in filtration.Comment: 7 pages, 8 figure

Facilitators and barriers for acquiring physical literacy for working and retired adults.

Facilitators and barriers for acquiring physical literacy for working and retired adults.</p

Main themes and sub-themes of acquiring physical literacy as an adult.

Main themes and sub-themes of acquiring physical literacy as an adult.</p

Interview guide.

AimsPhysical literacy is an emerging strategy to increase participation in movement activities for children and youth, however little is known about how to frame physical literacy for aging adults. The purpose of this qualitative study was to explore how adults with multiple chronic conditions describe physically literacy for adults and to understand the needs, preferences, barriers, and facilitators to acquiring and maintaining physical literacy despite fluctuations in health status.MethodsSixteen semi-structured interviews were conducted with working and retired teachers in Ontario, Canada, with varying self-identified physical activity levels and are living with 2 or more chronic conditions. A semi-structured interview guide was used to conduct the interviews. Thematic analysis was used to analyze the data.ResultsParticipants identified 5 themes when describing physical literacy for adults: understanding one’s body, conscious commitment to movement, access to and knowledge of rehabilitation health resources, valuable physical activities, and confident problem solver. Results indicate that when acquiring physical literacy for adults, there are important new constructs, such as self-management and the awareness of rehabilitation strategies to maintain mobility, that differ from the traditional physical literacy model.ConclusionsTo improve function and mobility outcomes for adults living with chronic conditions, programs should be guided by a physical literacy framework that addresses the needs unique to aging adults, such as understanding the changes that occur with aging, self-monitoring mobility changes and participating in rehabilitation strategies.</div

Demographic characteristics of interview participants (N = 16).

Demographic characteristics of interview participants (N = 16).</p

e-Delphi survey process and timeline.

e-Delphi survey process and timeline.</p

Late-life disability instrument frequency domain scores for the study group and control group.

The box represents the 25th to 75th percentiles with the horizontal line inside the box representing the median score. The horizontal lines above and below the box represent the maximum (75th percentile plus 1.5*IQR) and minimum (25th percentile minus 1.5*IQR) scores. IQR = interquartile range.</p

Participant characteristics.

Participant characteristics.</p