Previous events - Page 55

Recent advances in experimental techniques have enabled remarkable discoveries and insight into how the dynamics of thin gas/vapour films can profoundly influence the behaviour of liquid droplets: drops impacting solids can “skate on a film of air” [1], so that they can “bounce off walls” [2,3]; reductions in ambient gas pressure can suppress splashing [4] and initiate the merging of colliding droplets [5]; and evaporating droplets can levitate on their own vapour film [7] (the Leidenfrost effect). Despite these advances, the precise physical mechanisms governing these phenomena remain a topic of debate.  A theoretical approach would shed light on these issues, but due to the strongly multiscale nature of these processes brute force computation is infeasible.  Furthermore, when films reach the scale of the mean free path in the gas (i.e. ~100nm) and below, new nanoscale physics appears that renders the classical Navier-Stokes paradigm inaccurate.

In this talk, I will overview our development of efficient computational models for the aforementioned droplet dynamics in the presence of gas nanofilms into which gas-kinetic, van der Waals and/or evaporative effects can be easily incorporated [8,9].  It will be shown that these models can reproduce experimental observations – for example, the threshold between bouncing and wetting for drop impact on a solid is reproduced to within 5%, whilst a model excluding either gas-kinetic or van der Waals effects is ~170% off!  These models will then be exploited to make new experimentally-verifiable predictions, such as how we expect drops to behave in reduced pressure environments.  Finally, I will conclude with some exciting directions for future work.

[1] JM Kolinski et al, Phys. Rev. Lett.  108 (2012), 074503. [2] JM Kolinski et al, EPL.  108 (2014), 24001. [3] J de Ruiter et al, Nature Phys.  11 (2014), 48. [4] L Xu et al, Phys. Rev. Lett. 94 (2005), 184505. [5] J Qian & CK Law, J. Fluid. Mech. 331 (1997), 59.  [6] KL Pan J. Appl. Phys. 103 (2008), 064901. [7] D Quéré, Ann. Rev. Fluid Mech. 45 (2013), 197.  [8] JE Sprittles, Phys. Rev. Lett.  118 (2017), 114502.  [9] MV Chubynsky et al, Phys. Rev. Lett.. 124 (2020), 084501.
Much of this work is based on a recent Annual Review: JE Sprittles, Ann. Rev. Fluid Mech. 56 (2024), 91.

Doctoral candidate Ola Sande at the Department of Mathematics will be defending the thesis Hyperétale Framed Correspondences for the degree of Philosophiae Doctor.

Welcome to the first SUSTAINITtalk where Professor Einar Broch Johnsen will present the innovative project, Digital Twin. What is a digital twin?

Alexander is Professor of music technology and Director of RITMO Centre for Interdisciplinary Studies in Rhythm, Time and Motion (IMV) at the University of Oslo.

by Annique van der Boon

Centre for Planetary Habitability

This week, Kishore Thapliyal will tell us more about sensing, by giving a journal club on the paper:

Hylleraas seminar, hosted in Oslo

The internal waves in consideration are generated locally in combination by:
1) the North Atlantic Current (NAC) that flows along the Norwegian shelf (average speed 0.3 m/s),
2) the local tide (dominant 24 hr mode),
3) the particular shelf geometry,
4) the seasonal pycnocline (at 20 m depth). The typical amplitude is 50 m. The local depth where they exist is 100 m (approx.).
The local internal wave speed of 0.4 m/s is comparable to the current speed.

The wave generation process occurs in a sequence of:
A) locally large depressions of the internal tide occurring at the lee side of two shallow ridges,  
B) the depressions are orthogonal to the current,
C) the depressions move slowly against the current, and
D) eventually fission into nonlinear-dispersive wave groups,
E) they propagate upstream against the current,
F) they are recorded on satellite images and is visible by eye.
 

In a recent RCN-funded project (ECOPULSE) 2020-2023 including research groups at UiO, the Norwegian Meteorological Institute and the Institute of Marine Research in Bergen, field experiments of the mother wave in points A) and C) were undertaken during July-September 2021 and 2022. The measurements show that the waves break and mix in the entire water column by convective breaking in the upper part of the water column, shear instability within the pycnocline, and by a variant of a shear instability near the bottom. The field measurements document the local wave properties and the initial phase of the fission process. The Vesterålen-Lofoten area is of immense political interest because of a) its traditional fisheries and breeding ground for the North Atlantic and Barents Sea Cod and other species, where also a cold water coral reef is located right where these waves are generated.  The waves do also extend across NORDLAND VII, an oil / gas field which may be considered for exploitation. Preliminary results will be presented.

Doctoral candidate Karl Martin Frøseth Forbord at the Department of Pharmacy, Faculty of Mathematics and Natural Sciences, is defending the thesis "The cysteine protease legumain in paracrine and endocrine regulation of bone health" for the degree of Philosophiae Doctor.

Whole-genome amplification and sequencing of Hepatitis B Virus from serum samples

Mens unge skåret høyere og høyere på kognitive tester i årene etter andre verdenskrig, har dette nå snudd. Hvilke konsekvenser vil dette kunne ha?

C*-algebra seminar by David Jaklitsch (University of Oslo).

Doctoral candidate Bernhard Baumschlager at the Institute of Theoretical Astrophysics, Faculty of Mathematics and Natural Sciences, is defending the thesis "The Role of Radiation in Galaxy Formation and Evolution" for the degree of Philosophiae Doctor.

by Assoc Prof Judith Reindl,  Biophysics and Medical Physics, Department of Physics, UiO.

PhD candidate Rowen Monks will give a seminar on: Challenging a paradigm in aquatic microbial ecology: plans for investigating the uncertain role of the nuisance algae, Gonyostomum semen and associated microbia, in organic nitrogen cycling.

Join us for this week’s dScience Lunch Seminar with Krubeal Danieli as he explores how bio-inspired AI enables flexible navigation. His research, drawing on neuroscience, models how the brain forms internal maps in real time, allowing agents to explore and navigate without extensive training. This talk bridges the gap between neuroscience and AI. Complimentary lunch included!

Hei du! Lurer du på hva du skal bli? Bli med på inspirasjonsdagen og hør hva studenter innen kjemi, psykologi, farmasi, ernæring, odontologi og medisin forteller fra sine fag. Gratis arrangement.

The convention is an annual networking event that brings together Nordic and invited international experts to present their research and to discuss latest developments in the field of microphysiological systems, organoids and organ-on-chip technology.

På Bioteknologidagen får du høre om høydepunktene fra året som gikk og hva vi tror vil prege 2025 videre.

Join us for an interactive 2-hour workshop on image sonification designed for biology researchers eager to expand their toolkit for data exploration. During the workshop you will get introduced to the potential of integrating auditory feedback into your research process.

Technology Outlook: The Future of AI and Robotics in Healthcare.

As artificial intelligence and robotics continue to advance, their role in healthcare is becoming increasingly significant. At the Norway Life Science Conference 2025, dScience is organising a parallel session that explores how these technologies are reshaping the health sector. Leading experts will present key developments, challenges, and opportunities, offering insights into what the future holds.

At this seminar PhD students, postdocs and Master´s students in life sciences at UiO and NMBU will hear inspirational talks from people who have made careers outside academia. And get advice on how to build their own careers.

Open lectures on the prerequisites for life, the origin and evolution of life, and the possibilities of life elsewhere in the universe by Trond H. Torsvik, Sarah Johnson, Liv Hornekær, and Tue Hassenkam. The event will be held in English.