Soft Matter and Complex Systems Seminar
2006/2007 | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025
2024-01-19 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30 
Luis Carnevale (IF PAN)MDPD simulations of the Rayleigh-Plateau instability on surfactant-laden liquid threads
Formation of droplets is a fundamental process used in many industrial applications, such as inkjet printing and drug manufacturing. These droplets are often formed from the break-up of a liquid thread driven by a surface tension dependent instability, namely the Rayleigh-Plateau instability. We can reduce the surface tension by adding surfactants, which are molecules that adsorb on the interface of liquids, and thus, change the break-up dynamics. At certain systems with ultra-low surface tension or very small length scales, thermal fluctuations on the interface are capable of creating the instability that leads to the formation of droplets and satellite droplets. In our study, we employ simulations of a coarse-grained model known as many-body dissipative particle dynamics (MDPD) to determine the characteristic wavelength of such instabilities on liquid nanothreads with various surfactant concentrations, above and below its critical aggregation concentration. Also, we have identified the different break-up regimes, their time-scales and local concentration distributions that develop due to surfactant advection . We anticipate that our study contributes to the understanding of a fundamental process in nature and paves the way for further developments in this area for relevant applications.
2024-01-12 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Mateusz Wlazło (Centre of New Technologies, UW)Symmetry-breaking effects in pressure and temperature-induced metal-insulator transition in yttrium nickelate
Focusing on the long-range ordered antiferromagnetic and paramagnetic YNiO3 phases, we show the interplay between spin and structural motifs under pressure and their impact on electronic properties. Within density functional theory, we successfully describe the two insulating phases of YNiO3, a perovskite oxide traditionally classified as a strongly correlated material. We attribute the role of specific symmetry-breaking motifs in phase transitions concurrent with band gap opening and closing. This way we demonstrate how DFT can be used to gain a fundamental understanding of phase transitions in quantum materials, and what minimum level of theory is needed to describe such types of complex materials correctly.
2023-12-15 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Piotr Surówka (Institute of Theoretical Physics, Wrocław University of Science and Technology)Odd Viscoelasticity
Active matter encompasses systems that are not in equilibrium, consisting of elements that either consume energy or exert work. Consequently, their macroscopic characteristics diverge significantly from those predicted by continuum field theories based on equilibrium statistical mechanics. Recent advancements in active matter research have prompted a reevaluation of the fundamental principles of materials science. This has led to the development of a novel theoretical framework known as odd (visco)elasticity. Traditional elasticity treats solids as continuous media that change shape in response to external forces. On a microscopic scale, applying force to a crystalline structure displaces its atoms, which then exert a counterforce to regain the crystal's original configuration. However, this dynamic is fundamentally altered in active odd materials, where the response to applied forces includes not only compression or deformation but also deflection. In this presentation, I will provide an overview of the recent advancements in this field.
2023-12-08 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Bogdan Cichocki & Jeffrey Everts (IFT UW)Chiral active fluids in the creeping flow regime (Part II)
Viscosity is a property that tells us how easy it is to cause flow in a fluid. For incompressible isotropic systems, the most well-known type of viscosity is the shear viscosity, which quantifies how much of the fluid's available energy dissipates when a symmetric velocity gradient is induced into the system. However, the situation differs in so-called chiral active fluids, which are manifestly out-of-equilibrium systems. Here, the fluid particles are set into motion by activity or uniform rotation of the system and are, therefore, characterised by a non-trivial angular momentum density. Consequently, the flow properties of such a fluid are not just described by the shear viscosity. There are additional so-called odd viscosity coefficients that do not contribute to viscous dissipation in a direct manner.
Because of the fundamental interest in this problem and recent experiments, we study such chiral active fluids in the creeping flow regime in more detail. In part 1 of the seminar (1 December), we show that the fundamental solution can be explicitly constructed without any approximation for stationary three-dimensional incompressible flow. Our calculations form the basis for solving more complicated flow problems and for constructing the theory of hydrodynamic interactions in chiral active fluids. In part 2 of the talk (8 December), we will demonstrate how we can use the Green's function to construct an analytical exact solution for the single-particle problem. Furthermore, we will then explicitly demonstrate that odd viscosity can contribute to viscous dissipation via alteration of the fluid flow.
Because of the fundamental interest in this problem and recent experiments, we study such chiral active fluids in the creeping flow regime in more detail. In part 1 of the seminar (1 December), we show that the fundamental solution can be explicitly constructed without any approximation for stationary three-dimensional incompressible flow. Our calculations form the basis for solving more complicated flow problems and for constructing the theory of hydrodynamic interactions in chiral active fluids. In part 2 of the talk (8 December), we will demonstrate how we can use the Green's function to construct an analytical exact solution for the single-particle problem. Furthermore, we will then explicitly demonstrate that odd viscosity can contribute to viscous dissipation via alteration of the fluid flow.
2023-12-01 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Bogdan Cichocki & Jeffrey Everts (IFT UW)Chiral active fluids in the creeping flow regime (Part I)
Viscosity is a property that tells us how easy it is to cause flow in a fluid. For incompressible isotropic systems, the most well-known type of viscosity is the shear viscosity, which quantifies how much of the fluid's available energy dissipates when a symmetric velocity gradient is induced into the system. However, the situation differs in so-called chiral active fluids, which are manifestly out-of-equilibrium systems. Here, the fluid particles are set into motion by activity or uniform rotation of the system and are, therefore, characterised by a non-trivial angular momentum density. Consequently, the flow properties of such a fluid are not just described by the shear viscosity. There are additional so-called odd viscosity coefficients that do not contribute to viscous dissipation in a direct manner.
Because of the fundamental interest in this problem and recent experiments, we study such chiral active fluids in the creeping flow regime in more detail. In part 1 of the seminar (1 December), we show that the fundamental solution can be explicitly constructed without any approximation for stationary three-dimensional incompressible flow. Our calculations form the basis for solving more complicated flow problems and for constructing the theory of hydrodynamic interactions in chiral active fluids. In part 2 of the talk (8 December), we will demonstrate how we can use the Green's function to construct an analytical exact solution for the single-particle problem. Furthermore, we will then explicitly demonstrate that odd viscosity can contribute to viscous dissipation via alteration of the fluid flow.
Because of the fundamental interest in this problem and recent experiments, we study such chiral active fluids in the creeping flow regime in more detail. In part 1 of the seminar (1 December), we show that the fundamental solution can be explicitly constructed without any approximation for stationary three-dimensional incompressible flow. Our calculations form the basis for solving more complicated flow problems and for constructing the theory of hydrodynamic interactions in chiral active fluids. In part 2 of the talk (8 December), we will demonstrate how we can use the Green's function to construct an analytical exact solution for the single-particle problem. Furthermore, we will then explicitly demonstrate that odd viscosity can contribute to viscous dissipation via alteration of the fluid flow.
2023-11-24 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Daniel Wójcik (Nencki Institute of Experimental Biology, PAS)Statistical framework for identification of individual and social aspects of animal learning in intelligent cages
Several recent cage designs support studies of multiple animals housed for weeks with minimal human intervention in a single or multiple compartments where they can interact with cage elements and with each other, and their behavior can be tracked in various ways. Here we focus on Intellicage system where up to 14 female mice housed together can be identified with an RFID transponder interacting with intelligent corners providing reward, and the behavior is described in terms of discrete events. We present a general conceptual, analytical and computational framework for stochastic description, analysis and modeling of data from such cages. This framework combines the theory of point processes (as used in spike train analysis) with reinforcement learning models. We demonstrate how individual and social aspects of learning can be identified within the data, and show different specific approaches which facilitate study of effects of the whole group on an animal or formation of a hierarchy of social effects in group learning. The results of the analysis are validated with equivalent simulated data.
To illustrate this conceptual framework and our analytical approach we designed an experimental paradigm where rewards are offered depending on an arbitrary assignment of an animal to one of two groups, “majority” or “minority”. The two groups were assigned different locations with reward availability, changing in consecutive phases of the experiment. We show that the data support importance of the social effects in animal learning of the reward and may also be used to identify a social structure within the group. Corresponding generative models can be used for validation of various analytical methods and for prediction of mice behavior.
To illustrate this conceptual framework and our analytical approach we designed an experimental paradigm where rewards are offered depending on an arbitrary assignment of an animal to one of two groups, “majority” or “minority”. The two groups were assigned different locations with reward availability, changing in consecutive phases of the experiment. We show that the data support importance of the social effects in animal learning of the reward and may also be used to identify a social structure within the group. Corresponding generative models can be used for validation of various analytical methods and for prediction of mice behavior.
2023-11-17 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Annemiek Cornellissen and Camille Le Scao (Université Paris Cité)Morphogenesis of branching networks in jellyfish and fern leaves
Transport networks in living organisms show a variance of architecture, with either ramified or looped networks. These transport networks develop in parallel with the organisms, arising from local interactions and feedback mechanisms, resulting in self-organizing patterns.
In this presentation, we will first introduce general concepts used in morphogenesis, such as noise, instabilities and emergent patterns. We will then focus on the morphogenesis of the gastrovascular network of the jellyfish Aurelia aurita and on the vascular system of leaves.
In this presentation, we will first introduce general concepts used in morphogenesis, such as noise, instabilities and emergent patterns. We will then focus on the morphogenesis of the gastrovascular network of the jellyfish Aurelia aurita and on the vascular system of leaves.
2023-11-10 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Dorota Niedziałek ([1] Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. [2] Molecure S.A. Warsaw, Poland)The rocket science behind enzymatic machinery
The understanding of the catalytic process of a targeted enzyme might be a very important step for successful drug design process. Having an experimentally resolved structure is a must. Yet, it is merely a starting point of the way towards understanding the full picture of the enzyme's mechanism of action. There are several levels of theory we can use for studying an enzymatic machinery. The classical models fail to properly describe catalytic reactions. I would like to show you how we can overcome that limitations by using a combination of polarizable force field models and quantum mechanical calculations.
2023-11-03 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
no seminar on 3 Nov
2023-10-27 (Piątek)
Zapraszamy do sali 1.40, ul. Pasteura 5 o godzinie 09:30
Tomasz Woźniak (FUW)Optoelectronic properties of two-dimensional materials from first principles calculations
Since 2010, when the Nobel prize was awarded for exfoliation and measuring electric properties of graphene, two-dimensional (2D) materials have garnered significant attention from scientific and technological communities. This is, in part, due to their unique optoelectronic properties and the wide range of potential applications they offer in numerous fields. Moreover, their properties can be easily tuned by external and configurational factors. Up to now, dozens of 2D materials and structures have been synthesized and characterized. Among them, MXenes, transition metal dichalcogenides and 2D magnets are particularly attractive for computation and memory devices.
Fundamental properties of materials can be accurately described and predicted by first principles calculations. They also provide the input parameters for simulation of realistic devices within effective models. I will introduce the basic elements of Density Functional Theory (DFT), in the context of optoelectronic features of 2D materials.
I will present how first principles calculations, within DFT, can support interpretation of optical measurements and predict new 2D materials and structures, on the examples of transition metal dichalcogenides, monochalcogenides, thiophosphates, newly discovered MA2Z4 compounds and their heterostructures. I will show how DFT can quantitatively explain their optoeletronic properties under mechanical strain, pressure and external magnetic field. Finally, I will present an outlook of my research on magnetooptical properties of 2D materials.
Fundamental properties of materials can be accurately described and predicted by first principles calculations. They also provide the input parameters for simulation of realistic devices within effective models. I will introduce the basic elements of Density Functional Theory (DFT), in the context of optoelectronic features of 2D materials.
I will present how first principles calculations, within DFT, can support interpretation of optical measurements and predict new 2D materials and structures, on the examples of transition metal dichalcogenides, monochalcogenides, thiophosphates, newly discovered MA2Z4 compounds and their heterostructures. I will show how DFT can quantitatively explain their optoeletronic properties under mechanical strain, pressure and external magnetic field. Finally, I will present an outlook of my research on magnetooptical properties of 2D materials.
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