The interaction of multiple bubbles in a Hele-Shaw channel

We 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-averaged model. For a single-bubble system we establish that, in general, the 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 to 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 are varied. We find that they exhibit intriguing similarities to the single-bubble bifurcation structure, which has implications for the existence of n-bubble steady states

\u3ci\u3eAmicus Curiae\u3c/i\u3e Brief of the Hon. Judith Fitzgerald (Bankruptcy Judge, Ret.), and Law Professors Pamela Foohey, George Kuney, Robert Lawless, Jonathan Lipson, Bruce A. Markell, Nancy Rapoport, Richard Squire, Ray Warner and Jack Williams, In Support of the Petitioner

Professor Pamela Foohey filed an amicus brief with a group of law professors and a former bankruptcy judge in MOAC Mall Holdings LLC v. Transform Holdco LLC

Production, chemical characterization, and sensory profile of a novel spirit elaborated from spent coffee ground

This study describes a process for the production of a spirit from spent coffee ground (SCG), the chemical composition, and sensory profile of this distillate. The process consisted in three steps starting with the extraction of aroma compounds by hydrothermal treatment of SCG, followed by the fermentation of this extract supplemented with sucrose to ethanol, and the fermented broth distillation. Seventeen volatile compounds were identified in the distillate (including alcohols, esters, aldehydes, and acids), all of them in concentrations able to promote pleasant characteristics to the product. Based on the chemical composition, \SCG\ spirit was considered as having organoleptic quality acceptable for human consumption. Twelve descriptors defined the sensory characteristics of this product, including clarity and brilliance (visual analysis), coffee, roasted, alcohol, elegance and frankly (olfactory analysis), bitter, astringent and pungent (gustatory analysis), and finesse (olfactory and gustatory analyses). Coffee was the most representative aroma by olfactory analysis. Based on the sensory analysis, \SCG\ spirit was considered as having features of a pleasant beverage, with smell and taste of coffee

Sediment transport partitioning in the swash zone of a large-scale laboratory beach

publisher: Elsevier articletitle: Sediment transport partitioning in the swash zone of a large-scale laboratory beach journaltitle: Coastal Engineering articlelink: http://dx.doi.org/10.1016/j.coastaleng.2015.11.001 content_type: article copyright: © 2015 Elsevier B.V. All rights reserved

Seeding Science, Courting Conclusions: Reexamining the Intersection of Science, Corporate Cash, and the Law

Social scientists have expressed strong views on corporate influences over science, but most attention has been devoted to broad, Black/White arguments, rather than to actual mechanisms of influence. This paper summarizes an experience where involvement in a lawsuit led to the discovery of an unexpected mechanism: A large corporation facing a multibillion-dollar court judgment quietly provided generous funding to well-known scientists (including at least one Nobel prize winner) who would submit articles to "open," peer-reviewed journals, so that their "unbiased science" could be cited in an appeal to the Supreme Court. On balance, the corporation's most effective techniques of influence may have been provided not by overt pressure, but by encouraging scientists to continue thinking of themselves as independent and impartial

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

The unpredictable nature of bubble evolution

Abstract Unpredictable dynamics arising from a sensitivity to initial conditions is commonly associated with chaos. We demonstrate how similar unpredictability manifests in a nonlinear system that possesses a large number of long-term outcomes, namely the propagation of an air bubble within a viscous fluid-filled channel. The system under investigation supports various stable states of single-bubble propagation. In addition, bubbles can readily break up during their propagation. Upon subjecting steadily-propagating bubbles to finite-amplitude perturbations in the form of localised channel constrictions, we identify localised regions of the driving flow rate for which the resulting evolutions are unpredictable. Visibly-indistinguishable bubbles are observed to evolve towards a multitude of long-term outcomes, including each of the stable states available to the initial bubble and various states of permanently-changed bubble topology. By combining high-precision experimental results with simulations of a depth-averaged lubrication model of the system, we determine that this behaviour is driven by a sensitive dependence on initial conditions within the vicinity of an unstable periodic orbit