Thu 01 Jun 11:30: Buckling of a fast drying drop of particle suspension
Fast evaporation of particle-suspension drops results in complex morphologies of the final dried granules. Understanding the morphological transformations is important to industrial processes such as spray drying where droplets of particulate suspensions are dried at a fast rate to produce granules of thermally sensitive materials. The transformation of an initial spherical shell to complex morphologies of the final dried granule has been attributed to the buckling of particle-packed shells. Here, we demonstrate a universal scaling law for buckling that depends on the particle size, hardness, particle packing and size of drying drop. The critical transition for buckling is set by a dimensionless number that measures the competition between the compressive stress generated by capillary forces and the elastic strength of the packing. The same dimensionless number is also responsible for cracking of drying colloidal films, suggesting a universality in the mechanical behaviour of particle packings saturated with a solvent. These results should enable design of hierarchically structured, buckle-free granules with varying porosity, surface composition and internal structure.
- Speaker: Mahesh Tirumkudulu, IIT Bombay
- Thursday 01 June 2023, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Wed 31 May 12:00: The interplay of deep Earth and surface processes shaping Southeast Asia and the Australian continents
It is now well-established that mantle convection and mantle processes influence Earth’s surface. However, it becomes important to carefully consider the timing and mechanisms that might drive these processes. For Southeast Asia, a significant Cretaceous-Eocene regional unconformity had been interpreted as a long hiatus in subduction along the southern Sundaland margin. I present work, namely forward geodynamic models of dynamic topography, that reconcile these surface observations with a shorter (~10-15 Myr) hiatus in subduction, which better explains the geological and geodynamic history of this region. In the case of the Cretaceous-age Eromanga Sea in Australia, new landscape evolution models suggest that dynamic topography plays a secondary role to lithospheric flexure and eustatic sea level. These examples highlight the need for numerical modelling approaches, and robust geological constraints, that allow us to test scenarios and evaluate the time-evolving dominance of key mechanisms controlling the evolution of Earth’s surface, which allows us to isolate the relative contributions of mantle flow, tectonics, and climate.
- Speaker: Sabin Zahirovic -- University of Sydney
- Wednesday 31 May 2023, 12:00-13:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Fri 26 May 16:00: The thermal and anisotropic structure of the top 300 km of the mantle
Abstract not available
- Speaker: Dan McKenzie
- Friday 26 May 2023, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Wed 24 May 16:00: Recent progress in imaging the subsurface structure of Mars by Zhurong rover radar
Detailed information of Martian subsurface structure and properties is crucial for studying the geological evolution and environmental changes of Mars, and constitutes one of the essential components of Mars exploration. By analyzing the low-frequency radar data collected by the Zhurong rover of China’s Tianwen-1 mission, a detailed Martian subsurface image has been constructed along the ~1,171 m traverse of the rover in southern Utopia Planitia. The image shows an approximately 70-m-thick, multi-layered structure below a less than 10-m-thick regolith, reflecting the occurrence of episodic water-involved resurfacing on Mars during the Late Hesperian to Amazonian. Though no direct evidence for the existence of liquid water was found, based on the new radar data, the presence of saline ice cannot be ruled out in the subsurface of the landing area.
- Speaker: Ling Chen -- Chinese Academy of Sciences
- Wednesday 24 May 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 31 May 12:00: TBC
Abstract not available
- Speaker: Sabin Zahirovic -- University of Sydney
- Wednesday 31 May 2023, 12:00-13:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 07 Jun 16:00: Seeing into the heart of a planet: InSights from the Martian Core
Abstract not available
- Speaker: Jessica Irving -- University of Bristol
- Wednesday 07 June 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 17 May 17:30: Squaring the circle: a coherent reconstruction of past species responses from multiple lines of evidence Building doors are card operated, so latecomers may not be able to access the venue.
Abstract not available
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Andrea Manica, Department of Zoology
- Wednesday 17 May 2023, 17:30-19:00
- Venue: Large Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Thu 08 Jun 11:30: Title to be confirmed
Abstract not available
- Speaker: Tom Bewley, UCSD
- Thursday 08 June 2023, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Wed 07 Jun 16:00: TBC
Abstract not available
- Speaker: Jessica Irving -- University of Bristol
- Wednesday 07 June 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 24 May 16:00: TBC
Abstract not available
- Speaker: Ling Chen -- Chinese Academy of Sciences
- Wednesday 24 May 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 31 May 12:00: TBC
Abstract not available
- Speaker: Sabin Zahirovic -- University of Sydney
- Wednesday 31 May 2023, 12:00-01:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 17 May 16:00: Magma overpressure and its importance for eruption triggering and explosivity
Abstract not available
- Speaker: Mike Cassidy -- University of Birmingham
- Wednesday 17 May 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Lisanne Jagt.
Wed 17 May 17:30: Squaring the circle: a coherent reconstruction of the past from multiple lines of evidence Building doors are card operated, so latecomers may not be able to access the venue.
Abstract not available
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Andrea Manica, Department of Zoology
- Wednesday 17 May 2023, 17:30-19:00
- Venue: Large Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Fri 09 Jun 11:30: Earthquakes, pseudotachylytes, and the mechanical evolution of the continents
Abstract not available
- Speaker: Alex Copley
- Friday 09 June 2023, 11:30-12:30
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Thu 11 May 11:30: Time-Lapse Volumetric Seismic Imaging of Water Masses at a Major Oceanic Confluence in the South Atlantic Ocean
Water-mass interaction processes within the Southern Ocean strongly influence the global oceanic circulation system. For example, the western side of the South Atlantic Ocean is dominated by the confluence between the Brazil Current (BC) and Falkland/Malvinas Current (MC). At this confluence, tropical/subtropical (i.e. warm and salty) waters are transported southward by the BC where they interact with subantarctic (i.e. cold and fresh) waters transported northward by the MC. This interaction creates a highly dynamic frontal system that is characterized by complex water mass interactions and intense diapycnal mixing. Here, we exploit time-lapse volumetric seismic imaging of the Brazil-Malvinas Confluence (BMC) in order to elucidate the detailed thermohaline structure of this critical region. Careful signal processing of a 25 terabyte survey, acquired during February 2013, reveals a spectacular northeastward dipping oceanic front that extends as deep as 1800 m. Significantly, a deep transient mesoscale eddy is embedded in this front. This eddy appears to grow and decay over 11 day period and it has a maximum diameter of 40 km. Time-lapsed imagery also reveals mesoscale to sub-mesoscale complexity at all depths. Long wavelength temperature fields extracted from our acoustic velocity measurements reveal a pattern of cool anomalies on the MC side together with a steep and fanning temperature gradient close to the front but above the eddy, indicative of heat transfer. Evolution of this prominent eddy embedded in the front can be independently investigated using velocity fields calculated from the GLORY S12v1 product for the period of interest. Tracked particles, which are released daily through the confluence area down to 1800 m, flow along the MC from 40° S to 36° S and are deflected clockwise by the BMC . This flow suggests that the observed eddy is cyclonic and related to MC recirculation, as a result of the combination of the steep continental slope and geometry of the BMC . In this way, cooler water masses are juxtaposed against the front.
- Speaker: Xiaoqing Chen (University of Cambridge)
- Thursday 11 May 2023, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Thu 11 May 11:30: Xiaoqing Chen, Earth Sciences and TBC
XiaoChen, Earth Sciences – Time-Lapse Volumetric Seismic Imaging of Water Masses at a Major Oceanic Confluence in the South Atlantic Ocean
Water-mass interaction processes within the Southern Ocean strongly influence the global oceanic circulation system. For example, the western side of the South Atlantic Ocean is dominated by the confluence between the Brazil Current (BC) and Falkland/Malvinas Current (MC). At this confluence, tropical/subtropical (i.e. warm and salty) waters are transported southward by the BC where they interact with subantarctic (i.e. cold and fresh) waters transported northward by the MC. This interaction creates a highly dynamic frontal system that is characterized by complex water mass interactions and intense diapycnal mixing. Here, we exploit time-lapse volumetric seismic imaging of the Brazil-Malvinas Confluence (BMC) in order to elucidate the detailed thermohaline structure of this critical region. Careful signal processing of a 25 terabyte survey, acquired during February 2013, reveals a spectacular northeastward dipping oceanic front that extends as deep as 1800 m. Significantly, a deep transient mesoscale eddy is embedded in this front. This eddy appears to grow and decay over 11 day period and it has a maximum diameter of 40 km. Time-lapsed imagery also reveals mesoscale to sub-mesoscale complexity at all depths. Long wavelength temperature fields extracted from our acoustic velocity measurements reveal a pattern of cool anomalies on the MC side together with a steep and fanning temperature gradient close to the front but above the eddy, indicative of heat transfer. Evolution of this prominent eddy embedded in the front can be independently investigated using velocity fields calculated from the GLORY S12v1 product for the period of interest. Tracked particles, which are released daily through the confluence area down to 1800 m, flow along the MC from 40° S to 36° S and are deflected clockwise by the BMC . This flow suggests that the observed eddy is cyclonic and related to MC recirculation, as a result of the combination of the steep continental slope and geometry of the BMC . In this way, cooler water masses are juxtaposed against the front.
- Speaker: Xiaoqing Chen (University of Cambridge)
- Thursday 11 May 2023, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Wed 10 May 16:00: Lowermost-mantle density and thermochemical structure from from recent normal-mode measurements
Abstract not available
- Speaker: Rûna van Tent -- Utrecht University
- Wednesday 10 May 2023, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Lisanne Jagt.
Fri 02 Jun 16:00: Title to be confirmed
Abstract not available
- Speaker: Thomas Bewley, UC San Diego
- Friday 02 June 2023, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Tue 06 Jun 12:00: The seawater calcium concentration may be a key driver of long-term pCO2
The drawdown of CO2 via the temperature-dependent weathering of silicate minerals is canonically thought to be one of the key processes acting to maintain Earth’s climate within narrow bounds. However, the climatic responsiveness of weathering on multi-million-year timescales, to my knowledge, remains to be demonstrated. If no such relationship exists, or is weaker than typically presumed, previously unexplored factors may be important in driving long-term carbon cycle changes. One such parameter may be the calcium concentration of seawater, via the effect that it has on CaCO3 preservation in the ocean, explored here using a new, near-continuous Cenozoic record of seawater major ion chemistry. The Cenozoic [Ca2+sw] record closely corresponds to the timing of atmospheric CO2 changes, potentially implying a common driver. Testing the causality of this relationship using a carbon cycle box model demonstrates that whether or not this is the case depends to a large degree on the slope of the relationship between climate and silicate weathering, with a shallow slope implying that [Ca2+sw] is likely to drive the system. Given the recently identified major change in the Neogene global sea floor spreading rate, this finding potentially shifts the key driver of long-term climate from the terrestrial to marine realm, and at the very least, highlights the need to determine whether silicate weathering is responsive to climate change on geologic timescales before the long-term drivers of CO2 can be determined.
- Speaker: David Evans, University of Southampton
- Tuesday 06 June 2023, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Oscar Branson.
Tue 06 Jun 12:00: The seawater calcium concentration may be a key driver of long-term pCO2
The drawdown of CO2 via the temperature-dependent weathering of silicate minerals is canonically thought to be one of the key processes acting to maintain Earth’s climate within narrow bounds. However, the climatic responsiveness of weathering on multi-million-year timescales, to my knowledge, remains to be demonstrated. If no such relationship exists, or is weaker than typically presumed, previously unexplored factors may be important in driving long-term carbon cycle changes. One such parameter may be the calcium concentration of seawater, via the effect that it has on CaCO3 preservation in the ocean, explored here using a new, near-continuous Cenozoic record of seawater major ion chemistry. The Cenozoic [Ca2+sw] record closely corresponds to the timing of atmospheric CO2 changes, potentially implying a common driver. Testing the causality of this relationship using a carbon cycle box model demonstrates that whether or not this is the case depends to a large degree on the slope of the relationship between climate and silicate weathering, with a shallow slope implying that [Ca2+sw] is likely to drive the system. Given the recently identified major change in the Neogene global sea floor spreading rate, this finding potentially shifts the key driver of long-term climate from the terrestrial to marine realm, and at the very least, highlights the need to determine whether silicate weathering is responsive to climate change on geologic timescales before the long-term drivers of CO2 can be determined.
- Speaker: David Evans, University of Southampton
- Tuesday 06 June 2023, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Oscar Branson.