MEchanics GAthering -MEGA- Seminar: Talk1 - Non-toxic broad-spectrum anti-viral virucidal nano-materials; Talk2 - Particle size segregation and rheology interplay in dense granular flows
Event details
| Date | 11.04.2019 |
| Hour | 16:15 › 17:30 |
| Speaker | Matteo Gasbarri, SUNMIL, EPFL & Tomás Palacios, LHE, EPFL |
| Location | |
| Category | Conferences - Seminars |
Non-toxic broad-spectrum anti-viral virucidal nano-materials by Matteo Gasbarri, SUNMIL, EPFL
Despite the development of vaccines and antivirals, viruses are still a primary source of harm for humans. The recent outbreaks of pandemic such as Ebola or the percentages of people infected by contagious diseases such as HSV, HIV, influenza, show the urgency of different and efficient solutions against viruses. Recently, our group has demonstrated a novel approach to fighting viruses: antiviral nanomaterials that are broad-spectrum and non-toxic. The key feature of these nanomaterials is their capability of inhibiting viral infection in an irreversible way (i.e. with a virucidal mechanism). To the best of our knowledge these compounds were the first non-toxic virucidal nanomaterials. In this talk, the design rules to achieve such virucidal drugs will be showed along with the hypothesis on their mechanism of action. Indeed, the translation of this concepts on different nanomaterials will be discussed.
Particle size segregation and rheology interplay in dense granular flows by Tomás Palacios, LHE, EPFL
Particle-size segregation is produced when bulk grains, under the action of a mechanical force, sort themselves by their sizes. Most natural granular flows are gravity-driven, therefore they are subjected to basal shear stress, which produces relative movement between particle layers. Small grains are more likely to fall through the voids generated by larger particles displacement, generating the rising of the latter. Even though experimental and numerical evidence shows that large size ratios between small and large particles exacerbate segregation, a clear relation between segregation fluxes and size ratios is still missing. Rheological models (e.g. mu(I) rheology) usually consider a characteristic length for the grains but are unable to assess the role of particle-size segregation in bidisperse granular flows. My ongoing work seeks to provide a link between the mechanical response of dense granular flows and particle-size segregation. Three experimental setups are used to provide evidence on what drives the segregation of particles by their sizes and how it relates to the rheology or internal friction of the granular bulk. Experimental results show different segregation rates for identical external forcings under different particle-size ratios. Preliminary results highlight the internal frictional adaptation induced by particle-size segregation. Apparently, size segregation is a result of imbalanced pressure distribution that induces dilation and shear rate within the bulk. The higher the size ratio, the more imbalanced this distribution, the faster large grains move up.
Despite the development of vaccines and antivirals, viruses are still a primary source of harm for humans. The recent outbreaks of pandemic such as Ebola or the percentages of people infected by contagious diseases such as HSV, HIV, influenza, show the urgency of different and efficient solutions against viruses. Recently, our group has demonstrated a novel approach to fighting viruses: antiviral nanomaterials that are broad-spectrum and non-toxic. The key feature of these nanomaterials is their capability of inhibiting viral infection in an irreversible way (i.e. with a virucidal mechanism). To the best of our knowledge these compounds were the first non-toxic virucidal nanomaterials. In this talk, the design rules to achieve such virucidal drugs will be showed along with the hypothesis on their mechanism of action. Indeed, the translation of this concepts on different nanomaterials will be discussed.
Particle size segregation and rheology interplay in dense granular flows by Tomás Palacios, LHE, EPFL
Particle-size segregation is produced when bulk grains, under the action of a mechanical force, sort themselves by their sizes. Most natural granular flows are gravity-driven, therefore they are subjected to basal shear stress, which produces relative movement between particle layers. Small grains are more likely to fall through the voids generated by larger particles displacement, generating the rising of the latter. Even though experimental and numerical evidence shows that large size ratios between small and large particles exacerbate segregation, a clear relation between segregation fluxes and size ratios is still missing. Rheological models (e.g. mu(I) rheology) usually consider a characteristic length for the grains but are unable to assess the role of particle-size segregation in bidisperse granular flows. My ongoing work seeks to provide a link between the mechanical response of dense granular flows and particle-size segregation. Three experimental setups are used to provide evidence on what drives the segregation of particles by their sizes and how it relates to the rheology or internal friction of the granular bulk. Experimental results show different segregation rates for identical external forcings under different particle-size ratios. Preliminary results highlight the internal frictional adaptation induced by particle-size segregation. Apparently, size segregation is a result of imbalanced pressure distribution that induces dilation and shear rate within the bulk. The higher the size ratio, the more imbalanced this distribution, the faster large grains move up.
Practical information
- General public
- Free
Organizer
- MEGA.Seminar Organizing Committee