Invited Talk on “Interfacial Premelting and the Mechanics of Frost”
Speaker: Dr. Alan W. Rempel
Professor, Department of Geological Sciences, University of Oregon, USA
Schedule 29 August, 2023 (Tuesday) at 10:30 a.m.
Venue Auditorium, Pakistan Academy of Sciences (PAS), 3 – Constitution Avenue,
Sector G-5/2, Islamabad, Pakistan
Registration: There is no registration fee for participation in the event.
Zoom Link: https://us06web.zoom.us/j/83926136654?pwd=UHVha0NHM0srM2NTWmZYVkZkKytpdz09
ID: 839 2613 6654 Passcode: 075204
About the Speaker:
Prof. Dr. Alan W. Rempel is presently visiting Pakistan in connection with the Project titled: “Enhancing the study of Climate Change and Glaciology in Gilgit-Baltistan through collaboration between Karakoram International University, and the University of Oregon”. His areas of professional interest and expertise include: premelting and phase changes in porous media; mechanics and physics of ice, glaciers and subglacial beds; gas hydrates and submarine slope stability; strength evolution along faults; pore-fluid interactions; deformation and failure of granular materials in seismic and
surficial processes; and dynamics of solidifying lava flows. His current work is focused on solid-fluid interactions along faults during earthquakes and slow-slip events; the controls on glacier sliding that result in sediment entrainment and landscape evolution; the development of gas hydrateanomalies and their implications for submarine slope stability and pockmark formation; multiphase shear and transitions between distributed (viscous) and localized (frictional) deformation mechanisms, with application to fault mechanics.
Abstract of the Invited Talk:
Robert Frost’s 1914 masterpiece, Mending Wall, centers on the spring-time labors of two neighbors repairing damage to a stone wall that lines their common boundary. The rich symbolism of that poem has been thoroughly explored by many gifted scholars; in this talk we focus instead on less well-publicized scientific advances that have led to a nuanced understanding of the physical mechanisms that produce frost damage. Recognizing its importance in sculpting landscapes and compromising engineered structures, textbook explanations commonly invoke elevated pressures associated with the volumetric expansion that occurs as liquid water is transformed into solid ice. However, in the year of Mending Wall’s publication, the advent of accessible refrigeration equipment enabled Stephen Taber to begin a series of controlled experiments that first showed this density change to typically have only a negligible influence. Most natural and engineered systems are open to porous liquid flow so that instead, frost damage is primarily explained by a suction that draws liquid water towards colder regions where it freezes to facilitate crack growth. These thermomechanical interactions are now understood as a natural consequence of interfacial premelting, which can be viewed as a straightforward extension of wetting phenomena involving solids (here ice) that are separated from foreign substrates (e.g. rock) by thin films of their own melt (liquid water). The varied consequences of this behavior for mountainous landscapes, seasonally frozen soil, winter sports, glacier beds, and industrial processes transcend disciplinary boundaries.
Importance from Pakistan National View Point:
Pakistan has been ranked among the top ten climatically vulnerable countries in the world. Specifically, the Gilgit-Baltistan region of Pakistan, being one of the world’s most rugged and glaciated mountainous landscapes, is highly sensitive to the adverse impacts of climatic changes as is witnessed in the form of glacial melting at ever-increasing rates, extreme weather events, and the increasing
frequency of devastating floods, rock-fall and other climate hazards. The invited talk aims at: (1) addressing concerns about the presence and consequences of melt on ice surfaces at subzero temperatures, referred to as “premelting”; (2) providing a historical perspective on our understanding of the ice surface and consequences of premelting for a range of natural and engineering problems (e.g. snowflakes, cryopreservation, ice skating, freezethaw damage, glacier sliding); (3) emphasizing on the interactions of ice with soil particles that lead to the rich variety of behavior seen in such frost systems. As such, the invited talk is geared towards provoking discussion and brainstorming at the Academy (PAS) across disciplinary boundaries amongst the community of climate change specialists, environmentalists, ecologists, geologists, hydrogeologists, and bio-geographers who are invested in devising mitigation strategies that protect the safety and wellbeing of communities facing the menace of climate change.
– Prof. Dr. Khalid Mahmood Khan (S.I.), President PAS
– Prof. Dr. M. Qasim Jan (H.I., S.I., T.I), Fellow PAS
– Prof. Dr. Tasawar Hayat (H.I., S.I., T.I), Secretary General PAS
Coordinators – Dr. Riffat Mahmood Qureshi (Director Administration, PAS)/+92- 51-9215478
– Muhammad Naseer (Manager IT, PAS)/+92-345-6083069/Email: [email protected]
– Hamza Waheed (Incharge, PAS Technical Office)/+92- 51-9204843 / 9209684
– Ali Ahsan (Tech Officer, PAS Editorial Sec.)/0304-6739948/Email: [email protected]