BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Anna Balci (Charles University) DTSTART:20240103T080000Z DTEND:20240103T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/1 DESCRIPTION:Title: Numerical approximation of variational problems with general and or thotropic growth\nby Anna Balci (Charles University) as part of Modell ing of materials - theory\, model reduction and efficient numerical method s (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Christoph Allolio (Charles University) DTSTART:20240110T080000Z DTEND:20240110T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/2 DESCRIPTION:Title: Modeling Biomembranes and Organelles: Consequences of Molecular Spe cificity\nby Christoph Allolio (Charles University) as part of Modelli ng of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Petr Šácha (Charles University) DTSTART:20240221T080000Z DTEND:20240221T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/3 DESCRIPTION:Title: Numerical experiments and climate model development efforts in the Gravity wave research group at KFA MFF UK\nby Petr Šácha (Charles Un iversity) as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Jan Blechta (Charles University) DTSTART:20240228T080000Z DTEND:20240228T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/4 DESCRIPTION:Title: Divergence-preserving methods for incompressible flow\nby Jan B lechta (Charles University) as part of Modelling of materials - theory\, m odel reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Alena Jarolímová (Charles University) DTSTART:20240306T080000Z DTEND:20240306T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/5 DESCRIPTION:Title: Determination of Navier's slip parameter and the inflow velocity us ing variational data assimilation\nby Alena Jarolímová (Charles Univ ersity) as part of Modelling of materials - theory\, model reduction and e fficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Martin Čížek (Charles University) DTSTART:20240313T080000Z DTEND:20240313T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/6 DESCRIPTION:Title: Equations behind inelastic low-energy electron collisions with smal l molecules\nby Martin Čížek (Charles University) as part of Modell ing of materials - theory\, model reduction and efficient numerical method s (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Ondřej Souček (Charles University) DTSTART:20240320T080000Z DTEND:20240320T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/7 DESCRIPTION:Title: Variations in plume activity unveiling the dynamics of water-filled faults on Enceladus\nby Ondřej Souček (Charles University) as part of Modelling of materials - theory\, model reduction and efficient numeric al methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Jakub Fara (Charles University) DTSTART:20240327T080000Z DTEND:20240327T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/8 DESCRIPTION:Title: Beyond the edge of the ALE method: Simulation of Rebound\nby Ja kub Fara (Charles University) as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstrac t: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Alexander Wilkie (Charles University) DTSTART:20240403T070000Z DTEND:20240403T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/9 DESCRIPTION:Title: Realistic appearance modelling for movie VFX and 3D print applicati ons\nby Alexander Wilkie (Charles University) as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Alex Kaltenbach (TU Berlin) DTSTART:20240410T070000Z DTEND:20240410T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/10 DESCRIPTION:Title: Aposteriori error control for variational problems via convex dual ity\, explicit flux reconstruction\, and applications\nby Alex Kaltenb ach (TU Berlin) as part of Modelling of materials - theory\, model reducti on and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Erin Carson (Charles University) DTSTART:20240424T070000Z DTEND:20240424T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/11 DESCRIPTION:Title: Balancing Inexactness in Matrix Computations\nby Erin Carson ( Charles University) as part of Modelling of materials - theory\, model red uction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nOn su percomputers that exist today\, achieving even close to the peak performan ce is incredibly difficult if not impossible for many applications. Techni ques designed to improve the performance of matrix computations- making co mputations less expensive by reorganizing an algorithm\, making intentiona l approximations\, and using lower precision- all introduce what we can ge nerally call “inexactness”. The questions to ask are then:\n1. With al l these various sources of inexactness involved\, does a given algorithm s till get close enough to the right answer?\n2. Given a user constraint on required accuracy\, how can we best exploit and balance different types of inexactness to improve performance?\nStudying the combination of differen t sources of inexactness can thus reveal not only limitations\, but also n ew opportunities for developing algorithms for matrix computations that ar e both fast and provably accurate. We present few recent results toward th is goal\, involving mixed precision randomized decompositions and mixed pr ecision sparse approximate inverse preconditioners.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Jan Vybíral (Czech Technical University\, Faculty of Nuclear Scie nces and Physical Engineering) DTSTART:20240417T070000Z DTEND:20240417T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/12 DESCRIPTION:Title: Lower bounds in numerical mathematics\nby Jan Vybíral (Czech Technical University\, Faculty of Nuclear Sciences and Physical Engineerin g) as part of Modelling of materials - theory\, model reduction and effici ent numerical methods (UNCE MathMAC)\n\n\nAbstract\nIn the analysis of alg orithms\, there is usually a big difference between upper and lower bounds . Upper bounds (on the running time\, memory used or necessary input infor mation) is usually achieved by a construction of an efficient algorithm. O n the other hand\, lower bounds show that the construction of better and b etter algorithms has some natural limits. We study lower bounds on the amo unt of input information needed for algorithms in numerical analysis. The problems discussed include numerical integration\, signal processing\, and discrete geometry. Naturally\, we encounter connections to functional ana lysis\, probability\, and combinatorics.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Carola Bibiane Schönlieb (Department of Applied Mathematics and T heoretical Physics\, University of Cambridge) DTSTART:20240906T120000Z DTEND:20240906T130000Z DTSTAMP:20260404T093358Z UID:MathMAC/13 DESCRIPTION:Title: Mathematical imaging: From geometric PDEs and variational modellin g to deep learning for images\nby Carola Bibiane Schönlieb (Departmen t of Applied Mathematics and Theoretical Physics\, University of Cambridge ) as part of Modelling of materials - theory\, model reduction and efficie nt numerical methods (UNCE MathMAC)\n\n\nAbstract\nImages are a rich sourc e of beautiful mathematical formalism and analysis. Associated mathematica l problems arise in functional and non-smooth analysis\, the theory and nu merical analysis of nonlinear partial differential equations\, inverse pro blems\, harmonic\, stochastic and statistical analysis\, and optimisation. In this talk we will learn about some of these mathematical problems\, ab out variational models and PDEs for image analysis and inverse imaging pro blems as well as recent advances where such mathematical models are comple mented and replaced by deep neural networks. The talk is furnished with ap plications to art restoration\, forest conservation and cancer research.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Vít Průša (Mathematical Institute\, Faculty of Mathematics and Physics\, Charles University) DTSTART:20241002T070000Z DTEND:20241002T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/14 DESCRIPTION:Title: Negative thoughts on negative mass\nby Vít Průša (Mathemati cal Institute\, Faculty of Mathematics and Physics\, Charles University) a s part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nThe concept of effective m ass is frequently used for simplification of complex models. It i claimed that in the case of wave transmission analysis of some metamaterials the c orresponding effective mass can be frequency dependent\, negative and it m ay not even be a scalar quantity. These findings have even led some author s to suggest that Newton's second law needs to be modified within the cont ext of classical continuum mechanics. While there is nothing wrong with th e mathematical procedures used to reach these conclusions\, the accompanyi ng physical interpretation thereof is absurd. We show that the puzzling co ncept of negative mass can be easily eliminated provided that we model the corresponding metamaterials using an effective constitutive relation. The effective constitutive relation is a rate-type constitutive relation\, an d the simple models we study give a clue how to design a non-trivial effec tive rate-type constitutive relation that is conservative\, that is\, poss essing an associated conserved energy depending on the force/stress and it s time derivatives. In short\, the rate-type constitutive relations obtain ed in our study might be seen as a revival of hypoelastic materials.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Michal Outrata DTSTART:20241009T070000Z DTEND:20241009T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/15 DESCRIPTION:Title: Domain Truncation\, Absorbing Boundary Conditions\, Schur Compleme nts\, and Padé Approximation\nby Michal Outrata as part of Modelling of materials - theory\, model reduction and efficient numerical methods (U NCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Michal Bathory DTSTART:20241016T070000Z DTEND:20241016T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/16 DESCRIPTION:Title: Relative energy inequality for viscoelastic fluid models with appl ications to stability\nby Michal Bathory as part of Modelling of mater ials - theory\, model reduction and efficient numerical methods (UNCE Math MAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Umberto Zerbinati DTSTART:20241023T070000Z DTEND:20241023T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/17 DESCRIPTION:Title: A Kinetic Framework for Fluids with Partial Ordering\nby Umber to Zerbinati as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Radomír Chabiniok DTSTART:20241030T080000Z DTEND:20241030T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/18 DESCRIPTION:Title: Biomechanical Modeling for Congenital Heart Diseases\nby Radom ír Chabiniok as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Michal Pavelka DTSTART:20241106T080000Z DTEND:20241106T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/19 DESCRIPTION:Title: Modelling superfluid helium\nby Michal Pavelka as part of Mode lling of materials - theory\, model reduction and efficient numerical meth ods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Petr Pelech\, Läetitia Lebec DTSTART:20241113T080000Z DTEND:20241113T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/20 DESCRIPTION:Title: Semester seminar of junior researchers\nby Petr Pelech\, Läet itia Lebec as part of Modelling of materials - theory\, model reduction an d efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Kim Myyryläinen\, Anna Balci DTSTART:20241120T080000Z DTEND:20241120T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/21 DESCRIPTION:Title: Semester seminar of junior researchers\nby Kim Myyryläinen\, Anna Balci as part of Modelling of materials - theory\, model reduction an d efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Liam Burke\, Yuxin Ma DTSTART:20241127T080000Z DTEND:20241127T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/22 DESCRIPTION:Title: Semester seminar of junior researchers\nby Liam Burke\, Yuxin Ma as part of Modelling of materials - theory\, model reduction and effici ent numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Petr Šácha\, Lenka Slavíková DTSTART:20241204T080000Z DTEND:20241204T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/23 DESCRIPTION:Title: Semester seminar of junior researchers\nby Petr Šácha\, Lenk a Slavíková as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Jan Blechta\, Michal Outrata DTSTART:20241211T080000Z DTEND:20241211T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/24 DESCRIPTION:Title: Semester seminar of junior researchers\nby Jan Blechta\, Micha l Outrata as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Ondřej Chrenko\, Vojtěch Patočka DTSTART:20241218T080000Z DTEND:20241218T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/25 DESCRIPTION:Title: Semester seminar of junior researchers\nby Ondřej Chrenko\, V ojtěch Patočka as part of Modelling of materials - theory\, model reduct ion and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Alexei Gazca Orozco DTSTART:20250219T080000Z DTEND:20250219T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/26 DESCRIPTION:Title: A priori and a posteriori estimates for vectorial problems via con vex duality\nby Alexei Gazca Orozco as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\ n\n\nAbstract\nBy exploiting remarkable properties of the Crouzeix-Raviart and Raviart-Thomas finite elements\, numerous works in recent years have been able to employ convex duality theory to derive error estimates for a diverse set of problems\, including total variation minimisation\, the p-L aplacian\, the obstacle problem\, elastoplastic torsion\, among others. Ho wever\, virtually all of the available results have been developed for sca lar problems with homogeneous Dirichlet boundary conditions. This work ext ends the existing results in three directions\, taking the incompressible Stokes and linear elasticity systems as prototypical examples: it consider s vectorial as opposed to just scalar problems\, it includes non-homogeneo us mixed boundary conditions\, as well as loads in the dual of the energy space.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Ondřej Kincl DTSTART:20250226T080000Z DTEND:20250226T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/27 DESCRIPTION:Title: Understanding Smoothed Particle Hydrodynamics\nby Ondřej Kinc l as part of Modelling of materials - theory\, model reduction and efficie nt numerical methods (UNCE MathMAC)\n\n\nAbstract\nThis talk provides a be ginner-friendly overview of weakly compressible Smoothed Particle Hydrodyn amics (SPH)\, a mesh-free method for solving the Navier-Stokes equations. I will explain fundamental concepts such as smoothing kernels\, the two-st ep approximation of spatial derivatives\, and symplectic integrators for t ime discretization. The benefits and limitations of SPH will be compared t o mesh-based approaches like the Finite Element Method. Finally\, I will i llustrate key ideas from the convergence analysis of Di Lisio et al.\, whi ch relies on the Wasserstein metric and offers valuable theoretical insigh t.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Marc Fehling DTSTART:20250305T080000Z DTEND:20250305T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/28 DESCRIPTION:Title: hp-adaptive finite element methods\nby Marc Fehling as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nhp-adaptive finite element methods allow to choose both the mesh size h and the polynomial degree p locally o n every cell. Despite their excellent convergence properties\, these metho ds are not widely used\, likely due to the complexities involved in their implementation. To facilitate their use\, we have recently introduced comp rehensive support for hp-adaptive methods in the open-source library deal. II\, including parallel computation capabilities for continuous Galerkin m ethods.\n\nIn this presentation\, we will explore the general idea behind hp-adaptive finite element methods\, address challenges encountered in the ir parallel implementation\, and showcase example applications developed u sing the deal.II library. Particular attention will be given to the design of efficient solvers for the resulting systems of equations.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Patrick E. Farrell (University of Oxford) DTSTART:20250312T150000Z DTEND:20250312T160000Z DTSTAMP:20260404T093358Z UID:MathMAC/29 DESCRIPTION:Title: Predicting the future by solving equations\nby Patrick E. Farr ell (University of Oxford) as part of Modelling of materials - theory\, mo del reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract \nHumans have sought to predict the future for as long as we have existed. One of the key ideas\nof the scientific revolution was that we can predic t the future of physical systems by writing\ndown the laws of physics as d ifferential equations and solving them. Our capacity to do this\nhas recen tly increased dramatically due to better computers\, and better algorithms . This\ntechnology has quietly revolutionised industrial civilisation in c ountless ways\, from\npredicting the weather a week in advance\, to design ing space planes without wind tunnels\, and\nto understanding the gravitat ional waves detected by LIGO. In this lecture I will review this\nsubject\ , discuss some of my own contributions\, and mention some important open p roblems in\nthe field.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Jiří Falta DTSTART:20250319T080000Z DTEND:20250319T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/30 DESCRIPTION:Title: Mathematical Modeling of Process-Structure Interaction in Machinin g\nby Jiří Falta as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nMa chining operations involve complex interactions between the cutting proces s and the structural dynamics of the machine-tool-workpiece system. The pr esentation provides an overview of mathematical models describing these in teractions\, focusing on dynamics\, vibrations\, and surface formation.\nT his overview presentation begins with a general introduction to the machin ing workflow from CAD-CAM to CNC\, linking it to structural behavior and s urface accuracy. This is followed by an analysis of representative machini ng processes—turning\, milling\, and grinding\, showing different physic al effects and their corresponding mathematical formulations. Finally\, an overview of simulation software development for milling will be presented \, demonstrating its role in machining process optimization.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/30/ END:VEVENT BEGIN:VEVENT SUMMARY:Malte Kampschulte DTSTART:20250326T080000Z DTEND:20250326T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/31 DESCRIPTION:Title: A variational view of nonlinear and linear viscoelastodynamics \nby Malte Kampschulte as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nTh e aim of this talk is to present a comprehensive variational\nview of visc oelastodynamics. First we will consider the modelling of the\nproblem from an energetical perspective. Then we will see how existence\nof solutions to static\, quasistatic and dynamic problems can all be\nderived by consec utive variational methods following that energetical\nstructure. Finally w e study the convergence to the linearization\nemploying the variational co ncept of $\\Gamma$-convergence. This is based\non joint work with B.Beneš ová and M.Kružík.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/31/ END:VEVENT BEGIN:VEVENT SUMMARY:Vít Průša DTSTART:20250402T070000Z DTEND:20250402T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/32 DESCRIPTION:Title: Effective models for mechanical response of metamaterials\nby Vít Průša as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nWe propose a thermodynamically based approach for constructing effective rate-type con stitutive relations describing finite deformations of metamaterials. The e ffective constitutive relations are formulated as second-order in time rat e-type Eulerian constitutive relations between only the Cauchy stress tens or\, the Hencky strain tensor and objective time derivatives thereof. In p articular\, there is no need to introduce additional quantities or concept s such as ``micro-level deformation''\,``micromorphic continua''\, or elas tic solids with frequency dependent material properties.\n\nMoreover\, the linearisation of the proposed fully nonlinear (finite deformations) const itutive relations leads\, in Fourier/frequency space\, to the same constit utive relations as those commonly used in theories based on the concepts o f frequency dependent density and/or stiffness. From this perspective the proposed constitutive relations reproduce the behaviour predicted by the f requency dependent density and/or stiffness models\, but yet they work wit h constant---that is motion independent---material properties. This is cle arly more convenient from the physical point of view. Furthermore\, the li nearised version of the proposed constitutive relations leads to the gover ning partial differential equations that are particularly simple both in F ourier space as well as in physical space.\n\nFinally\, we argue that the proposed fully nonlinear (finite deformations) second-order in time rate-t ype constitutive relations do not fall into traditional classes of models for elastic solids (hyperelastic solids/Green elastic solids\, first-order in time hypoelastic solids)\, and that the proposed constitutive relation s embody a new class of constitutive relations characterising elastic soli ds.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Jaroslav Hron DTSTART:20250409T070000Z DTEND:20250409T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/33 DESCRIPTION:Title: Numerical investigation of blood flows with slip boundary conditio ns\nby Jaroslav Hron as part of Modelling of materials - theory\, mode l reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\n Most studies of patient-specific blood flow models prescribe a no-slip bou ndary condition at the walls. Although its implementation is straightforwa rd\, its validity at the blood-vessel wall interface is questionable. It h as been suggested in (Nubar\, 1971) for example\, that a slip boundary con dition can be considered for blood flow in certain situations. We will dis cuss some effects of prescribing the Navier-type slip boundary condition\, which assumes a linear proportionality between the tangential part of the wall velocity and the shear stress using an additional parameter. Such co ndition can be extended to full fluid-structure interaction problem. Final ly\, given some measured flow data\, for example modern 4D-PC MRI image\, we use variational data assimilation approach to estimate the Navier's sli p parameter on the vessel wall for real data.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Milan Šimek\, Zdeněk Bonaventura DTSTART:20250416T070000Z DTEND:20250416T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/34 DESCRIPTION:Title: Non-Equilibrium Plasma–Water Interactions: Experimental and Theo retical Approaches\nby Milan Šimek\, Zdeněk Bonaventura as part of M odelling of materials - theory\, model reduction and efficient numerical m ethods (UNCE MathMAC)\n\n\nAbstract\nNitrogen is essential for industry an d agriculture\, but converting abundant atmospheric nitrogen into reactive forms requires signifi cant energy. Intermittent renewable energy sources (e.g.\, wind and solar) can power non-equilibrium plasma sources\, which effi ciently generate nitrogen- and oxygen-based reactive species (RONS). One common way to produce such reactive plasmas is through streamer–spar k discharges\, initiated by strong electric fi elds from nanosecond/micros econd pulsed high-voltage power sources. These discharges can operate in d irect contact with the liquid surface\, thus creating and storing RONS in so-called plasma-activated water (PAW). In the agri-food sector\, PAW offe rs a wide range of possible applications (e.g. suppression of bacterial ac tivity or nutrient solution for plants in hydroponic systems).\n\nThis sem inar aims to\, in two parts\, provide an overview of experimental and nume rical modeling approaches\, both aimed at optimizing RONS generation in no n-equilibrium plasmas and enhancing their incorporation into plasma-activa ted water.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/34/ END:VEVENT BEGIN:VEVENT SUMMARY:Karel Tůma DTSTART:20250423T070000Z DTEND:20250423T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/35 DESCRIPTION:Title: Multiwell model of phase separation: Arbitrarily strong total-spre ading case\nby Karel Tůma as part of Modelling of materials - theory\ , model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbst ract\nIn this work\, we revisit a multi-well phase separation model in the context of β–ω transformations in titanium alloys. We propose a new f ormulation by modifying the algebraic structure of the interfacial free en ergy. This adjustment relaxes the standard coercivity constraint on surfac e tensions in total-spreading regimes and\, importantly\, prevents the for mation of mixed ω–ω states—configurations that are crystallographica lly impossible. We demonstrate the effectiveness of the proposed model thr ough simplified simulations and outline a path toward more realistic three -dimensional modeling of β–ω phase transitions in titanium alloys.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/35/ END:VEVENT BEGIN:VEVENT SUMMARY:Patrick Farrell DTSTART:20250514T070000Z DTEND:20250514T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/36 DESCRIPTION:Title: Discretising the Stokes-Onsager-Stefan-Maxwell equations of multic omponent flow\nby Patrick Farrell as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\ n\nAbstract\nMulticomponent fluids are mixtures of distinct chemical speci es (i.e. components) that interact through complex physical processes such as cross-diffusion and chemical reactions. Additional physical phenomena often must be accounted for when modelling these fluids\; examples include momentum transport\, thermal effects\, and (for charged species) electric al effects.\n\nDespite the ubiquity of chemical mixtures in nature and eng ineering\, multicomponent fluids have received almost no attention from th e finite element community\, with many important applications remaining ou t of reach from numerical methods currently available in the literature.\n \nIn this talk\, we present a novel class of high-order finite element met hods for simulating cross-diffusion and momentum transport (i.e. convectio n) in multicomponent fluids modelled with the Stokes-Onsager-Stefan-Maxwel l equations. Our model can also incorporate local electroneutrality when t he species carry electrical charge\, making the numerical methods particul arly desirable for simulating liquid electrolytes in electrochemical appli cations. We discuss challenges that arise when discretising the partial di fferential equations of multicomponent flow\, as well as some salient theo retical properties of our numerical schemes.\n\nFinally\, we present numer ical simulations involving (i) the microfluidic non-ideal mixing of hydroc arbons and (ii) the transient evolution of a lithium-ion battery electroly te in a Hull cell electrode.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Jakub Cach DTSTART:20250521T070000Z DTEND:20250521T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/37 DESCRIPTION:Title: Traction profiles of the Turek benchmark and their relation to bif urcations for Navier Stokes fluids\nby Jakub Cach as part of Modelling of materials - theory\, model reduction and efficient numerical methods ( UNCE MathMAC)\n\n\nAbstract\nWe present a consistent numerical study on th e stability of the Navier-Stokes fluid in the confined flow around a cylin der. We performed the study within the Turek benchmark for Reynolds number s up to 1000. The key outcome is that changes in the nature of flow regime s are driven by the upstream dynamics of the cylinder obstacle rather than by the downstream effect in the vortex wake. It turns out that the most s ensitive indicator is the pointwise traction profile on the cylinder bound ary. Another observation is in the case of laminar vortex shedding\, where the multiple steady solutions differ from the global-in-time attractor\, which appears to be unique and robust across a large range of Reynolds num bers. As an auxiliary contribution\, we also discuss a weak (variational) formulation for traction computation\, which offers practical advantages.\ n LOCATION:https://stable.researchseminars.org/talk/MathMAC/37/ END:VEVENT BEGIN:VEVENT SUMMARY:Artem Ryabov DTSTART:20251001T070000Z DTEND:20251001T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/38 DESCRIPTION:Title: Solitary cluster waves in driven dense colloids\nby Artem Ryab ov as part of Modelling of materials - theory\, model reduction and effici ent numerical methods (UNCE MathMAC)\n\n\nAbstract\nWe will discuss the st atic and dynamic states of hard spheres confined in one-dimensional period ic potentials at high particle densities. Such systems can reside in a mec hanical equilibrium or in running states characterized by soliton-mediated transport [1-3]. For weak external driving\, these solitary cluster waves emerge in narrow intervals of specific particle sizes. The minimal number of particles needed to trigger the soliton propagation follows from condi tions of mechanical equilibrium and can be determined by a geometric princ iple of minimum residual free space. We further address the number of prop agating solitons\, their mutual interactions\, the influence of external f orcing\, and present experimental evidence for such solitary excitations i n driven colloidal systems [4].\n\n[1] AP Antonov\, A Ryabov\, P Maass\, P hys. Rev. Lett. 129\, 080601 (2022)\n[2] AP Antonov\, A Ryabov\, P Maass\, Chaos\, Solitons & Fractals 185\, 115079 (2024)\n[3] AP Antonov\, A Vonhu sen\, A Ryabov\, P Maass\, Nonlinear Dyn. (2025) doi: 10.1007/s11071-025-1 1626-x\n[4] E Cereceda-Lopez\, et al.\, Nat. Commun. 14\, 6448 (2023)\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/38/ END:VEVENT BEGIN:VEVENT SUMMARY:Aaron Baier-Reineo DTSTART:20251008T070000Z DTEND:20251008T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/39 DESCRIPTION:Title: Finite element methods for electroneutral multicomponent convectio n-diffusion\nby Aaron Baier-Reineo as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n \n\nAbstract\nMulticomponent fluids are those consisting of multiple chemi cal species. Complex physical processes occur within these fluids\; exampl es include cross-diffusion\, chemical reactions\, momentum transport\, the rmality and (for charged species) electrical effects. Despite their ubiqui ty in science and engineering\, multicomponent fluids have received limite d attention from the finite element community\, and many important applica tions remain out of reach from current numerical methods. In this talk\, w e present novel high-order finite element methods for multicomponent cross -diffusion and momentum transport. Our model can also incorporate local el ectroneutrality when the species carry electrical charge\, making the meth ods particularly desirable for simulating liquid electrolytes in electroch emical applications. We discuss challenges that arise when discretising th e governing partial differential equations\, as well as some salient theor etical properties of the numerical schemes. Finally\, we present numerical simulations involving (i) the microfluidic non-ideal mixing of hydrocarbo ns and (ii) a lithium-ion battery electrolyte in a Hull cell electrode.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/39/ END:VEVENT BEGIN:VEVENT SUMMARY:Josef Málek DTSTART:20251015T070000Z DTEND:20251015T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/40 DESCRIPTION:Title: On non-isothermal flows of dilute incompressible polymeric fluids< /a>\nby Josef Málek as part of Modelling of materials - theory\, model re duction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nIn t he first part of the talk\, we show that thermodynamically consistent mode ls for non-isothermal flows of such fluids can be derived in a very elemen tary manner. Our approach is based on identifying the energy storage mecha nisms and entropy production mechanisms in the fluid of interest\, which i n turn leads to explicit formulae for the Cauchy stress tensor and for all the fluxes involved. Having identified these mechanisms\, we first derive the governing system of nonlinear partial differerential equations coupli ng the unsteady incompressible temperature-dependent Navier–Stokes equat ions with a temperature-dependent generalization of the classical Fokker –Planck equation and an evolution equation for the internal energy. In t he second - main part - of the talk\, we show that sequences of smooth sol utions to the initial–boundary-value problem\, which satisfy the underly ing energy/entropy estimates (and their consequences in connection with th e governing system of PDEs)\, converge to weak solutions that satisfy a re normalized entropy inequality. The talk is based on joint results with Mir oslav Bulíček\, Mark Dostalík\, Vít Průša and Endré Süli.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/40/ END:VEVENT BEGIN:VEVENT SUMMARY:Simone Marras DTSTART:20251022T070000Z DTEND:20251022T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/41 DESCRIPTION:Title: Noise\, ripples\, and other oscillations in numerical weather > pr ediction. A brief survey of how to treat them.\nby Simone Marras as pa rt of Modelling of materials - theory\, model reduction and efficient nume rical methods (UNCE MathMAC)\n\n\nAbstract\nThe advent of inexpensive mass ively parallel computers in the past fifteen years has revolutionized the way numerical weather prediction\, climate and ocean modeling are handled today. In this talk\, I will describe how this revolution happened\, the r easons that drove it\, and what challenges are still to be fully addressed and resolved as exascale computing approaches.\n\nI will concentrate on t he use of high-order continuous and discontinuous spectral elements (SEM) as they are proving their mettle for solving the Navier-Stokes equations t o model atmospheric motion. Because of the high susceptibility of SEM to G ibbs oscillations in the solution to non-linear problems\, special attenti on will be given to understanding how their stabilization is still an acti ve topic of research and how we are contributing towards its solution.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Christoph Allolio DTSTART:20251105T080000Z DTEND:20251105T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/42 DESCRIPTION:Title: Molecular Grammar of Microtubule-Wetting Biomolecular Condensates< /a>\nby Christoph Allolio as part of Modelling of materials - theory\, mod el reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\ nBiomolecular condensates are a recently discovered new ordering principle of the cell. They consist of partially disordered proteins\, which underg o liquid-liquid phase separation inside the cytosol\, turning the cell int o a multiphase mixture. Microtubuli are the backbone of the cytoskeleton i n the sense that they are the entities inside the cell that is able to gen erate the largest mechanical force.\n\nMicrotubule condensate interactions are fundamental for cell division\, vesicle transport and cellular locomo tion. Accordingly\, they represent a large number of attractive drug targe ts. Due to the size of microtubuli and the slow timescale of condensate st ructural relaxation\, there has not been a systematic investigation at the molecular level as to what binding patterns (molecular grammar) enable co ndensate binding to microtubuli. We provide a protocol that is able to pre dict whether any given disordered protein sequence will bind to microtubul i. This protocol is suitable for high-throughput screening. Our pattern an alysis allows us to establish two categories of strongly interacting subse quences that enable binding to microtubuli: positively charged hydrophobic clusters and alternating charge sequences. Their overall optimal balance is analyzed and preferential regions of interaction on microtubuli are ide ntified and validated with known experimental results. Our results enable rapid prototyping of proteins that target the microtubule surface\, i.e. t hey predict whether unstructured proteins will wet the microtubule interfa ce.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/42/ END:VEVENT BEGIN:VEVENT SUMMARY:Umberto Zerbinati DTSTART:20251112T080000Z DTEND:20251112T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/43 DESCRIPTION:Title: A Kinetic Interpretation of Thermochemical Restrictions of Continu a\nby Umberto Zerbinati as part of Modelling of materials - theory\, m odel reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstrac t\nIn their seminal work\, Rajagopal and Srinivasa established how the sec ond law of thermodynamics\, expressed through the Clausius–Duhem inequal ity\, imposes powerful restrictions on the constitutive equations of conti nua\, often allowing one to determine the constitutive relations of a mate rial. This talk explores a kinetic interpretation of such thermochemical r estrictions. The analysis of the entropy balance naturally yields a kineti c analogue of the Clausius–Duhem inequality\, while the H-theorem provid es a microscopic justification of the second law. In the hydrodynamic limi t\, a Chapman–Enskog expansion demonstrates how the classical constituti ve relations of continuum mechanics—such as the Euler equations and the ideal gas law—arise as zeroth-order approximations that maximize entropy production. We hope that this kinetic perspective offers a new interpreta tion of the thermomechanical restrictions introduced by Rajagopal and coll aborators\, clarifying their origin within the statistical description of particle systems.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/43/ END:VEVENT BEGIN:VEVENT SUMMARY:S. Leveque\, R. Khan\, Y. Ma DTSTART:20251119T080000Z DTEND:20251119T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/44 DESCRIPTION:Title: Semester seminar of junior researchers\nby S. Leveque\, R. Kha n\, Y. Ma as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nSantolo Leve que

\nAn Augmented Lagrangian preconditioner for the control of t he Navier–Stokes equations
\nOptimal control problems with PDEs a s constraints arise very often in scientific and industrial applications. Due to the difficulties arising in their numerical solution\, researchers have put a great effort into devising robust solvers for this class of pro blems. An example of a highly challenging problem attracting significant a ttention is the distributed control of incompressible viscous fluid flow p roblems. In this case\, the physics is described by the incompressible Nav ier–Stokes equations. Since the PDEs given in the constraints are nonlin ear\, in order to obtain a solution of Navier–Stokes control problems on e has to iteratively solve linearizations of the problems until a prescrib ed tolerance on the non-linear residual is achieved. In this talk\, we pre sent efficient and robust preconditioned iterative methods for the solutio n of the stationary incompressible Navier–Stokes control problem\, when employing an inexact Newton linearization of the first-order optimality co nditions. The iterative solver is based on an augmented Lagrangian precond itioner. By employing saddle-point theory\, we derive suitable approximati ons of the (1\,1)-block and the Schur complement. Numerical experiments sh ow the effectiveness and robustness of our approach\, for a range of probl em parameters.

\n\n\nRitesh Khan

\nAccelerating Dense Matrix Computations Using Hierarchical Matrices
\nDense matrices arise fr equently across many areas\, such as PDEs\, inverse problems\, integral eq uations\, machine learning\, kernel methods\, etc. In many practical appli cations\, these dense matrices can be very large\, making matrix operation s involving them quite challenging. For example\, the direct evaluation of the dense matrix-vector product in the potential theory requires O(N^2) o perations and solving a dense linear system using naive direct methods (su ch as LU) requires O(N^3) operations. Both operations become computational ly prohibitive for large N. To address this\, large dense matrices are usu ally approximated using block low-rank representations\, commonly known as hierarchical matrices. In this talk\, I will discuss different types of h ierarchical matrices and how they can be used to design fast and scalable solvers. I’ll also show a few interesting applications that highlight th e power of hierarchical matrices.

\n\nYuxin Ma

\nOn a shrink -and-expand technique for symmetric block eigensolvers
\nIn symmetr ic block eigenvalue algorithms\, such as the subspace iteration algorithm and the locally optimal block preconditioned conjugate gradient (LOBPCG) a lgorithm\, a large block size is often employed to achieve robustness and rapid convergence. However\, using a large block size also increases the c omputational cost. Traditionally\, the block size is typically reduced aft er convergence of some eigenpairs\, known as deflation. In this work\, we propose a non-deflation-based\, more aggressive technique\, where the bloc k size is adjusted dynamically during the algorithm. This technique can be applied to a wide range of block eigensolvers\, reducing computational co st without compromising convergence speed. We present three adaptive strat egies for adjusting the block size\, and apply them to four well-known eig ensolvers as examples. Detailed theoretical analysis and numerical experim ents are provided to illustrate the efficiency of the proposed technique. In practice\, an overall acceleration of 20% to 30% is observed.

\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/44/ END:VEVENT BEGIN:VEVENT SUMMARY:Flora Philipp DTSTART:20251126T080000Z DTEND:20251126T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/45 DESCRIPTION:Title: Global Existence of Weak Solutions to Chemotaxis Navier-Stokes-Kor teweg systems\nby Flora Philipp as part of Modelling of materials - th eory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\ nAbstract\nA Chemotaxis compressible Navier–Stokes model was introduced to describe vascular network formation. Global existence for this system w as recently shown for adiabatic exponent $\\gamma>8/5$ by Huo and\nJ\\“u ngel. We regularize the equations by adding a Korteweg term and prove glob al existence for the regularized system\, allowing for smaller adiabatic e xponents ($\\gamma>1$). Our analysis is based on the use of a free energy as well as the BD-entropy\, and exploits additional regularity properties derived via the systematic integration-by-parts technique introduced by J\ \“ungel and Matthes. In the course of this\, we can also establish exist ence results for a broader class of Navier–Stokes–Korteweg systems\, w hich until now have only been investigated in two special cases: the Quant um-Navier–Stokes equation\nand the thin film equation.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/45/ END:VEVENT BEGIN:VEVENT SUMMARY:P. Šácha\, A. Gazca\, P. Pelech DTSTART:20251203T080000Z DTEND:20251203T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/46 DESCRIPTION:Title: Semester seminar of junior researchers\nby P. Šácha\, A. Gaz ca\, P. Pelech as part of Modelling of materials - theory\, model reductio n and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/46/ END:VEVENT BEGIN:VEVENT SUMMARY:V. Patočka\, L. Lebec\, O. Chrenko DTSTART:20251210T080000Z DTEND:20251210T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/47 DESCRIPTION:Title: Semester seminar of junior researchers\nby V. Patočka\, L. Le bec\, O. Chrenko as part of Modelling of materials - theory\, model reduct ion and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/47/ END:VEVENT BEGIN:VEVENT SUMMARY:M. Outrata\, M. Fehling\, J. Blechta DTSTART:20251217T080000Z DTEND:20251217T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/48 DESCRIPTION:Title: Semester seminar of junior researchers\nby M. Outrata\, M. Feh ling\, J. Blechta as part of Modelling of materials - theory\, model reduc tion and efficient numerical methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/48/ END:VEVENT BEGIN:VEVENT SUMMARY:Giulio Giusteri DTSTART:20260128T080000Z DTEND:20260128T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/49 DESCRIPTION:Title: Mathematical modeling of viscoelastic fluids\nby Giulio Giuste ri as part of Modelling of materials - theory\, model reduction and effici ent numerical methods (UNCE MathMAC)\n\n\nAbstract\nA class of continuum m echanical models aimed at describing the behaviorof viscoelastic materials will be presented. These models are obtained by incorporating concepts or iginated in the theory of solid plasticity in a fluid mechanics context [1 ]. Within this class\, even a simple model with constant material paramete rs is able to qualitatively reproduce a number of experimental observation s in both simple shear and extensional flows\, including linear viscoelast ic properties\, the rate dependence of steady-state material functions\, t he stress overshoot in incipient shear flows\, and the difference in shear and extensional rheological curves.\n\nThese constitutive models are base d on a logarithmic relation between the elastic strain measure and the str ess tensor and on evolution equations for a local representative of the el astically-relaxed strain state. Importantly\, it can be shown that classic al models are recovered by expanding the evolution equation for the elasti c stress around the null solution. The mathematical analysis of such tenso rial transport equations leads to the definition of the notion of charted weak solutions [2]. These are based on non-standard a priori estimates tha t involve both viscous and plastic energy dissipation. The main aspects an d open problems of the theoretical analysis of the evolution equations wil l be presented.\n\n[1] M. A. H Alrashdi\, G. G. Giusteri\, Evolution of lo cal relaxed states and the modeling of viscoelastic fluids\, Phys. Fluids\ , 36\, 093129\, 2024.\n[2] G. Ciampa\, G. G. Giusteri\, A. G. Soggiu\, Vis coelasticity\, logarithmic stresses\, and tensorial transport equations\, Math. Meth. Appl. Sci. 48\, 2934--2953\, 2025.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/49/ END:VEVENT BEGIN:VEVENT SUMMARY:Umberto Zerbinati DTSTART:20260211T080000Z DTEND:20260211T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/50 DESCRIPTION:Title: Structure-Preserving FEEC Methods for Spectral and Pseudospectral Analysis of Dynamo Operators\nby Umberto Zerbinati as part of Modellin g of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nNumerical dynamo problems involve advection –diffusion operators whose spectral and pseudospectral properties play a central role in determining growth rates\, stability\, and transient ampl ification. Their reliable numerical approximation remains challenging\, pa rticularly in advection-dominated and strongly non-normal regimes. In this talk\, I present a structure-preserving finite element exterior calculus (FEEC) framework for dynamo-type advection–diffusion operators acting on differential forms. The discretization is based on finite element de Rham complexes and preserves the geometric and topological structure of the co ntinuous problem. Within this setting\, we investigate the approximation o f spectra and pseudospectra and derive a priori error estimates for pseudo spectral convergence. We also discuss the role of exponential transformati ons for advection–diffusion operators and their consequences for the asy mptotic behavior of solutions.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/50/ END:VEVENT BEGIN:VEVENT SUMMARY:Vít Dolejší DTSTART:20260218T080000Z DTEND:20260218T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/51 DESCRIPTION:Title: Adaptive domain decomposition preconditioners for time-dependent f low problems\nby Vít Dolejší as part of Modelling of materials - th eory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\ nAbstract\nWe deal with the numerical solution of the time/dependent compr essible Navier-Stokes equations by the space-time adaptive discontinuous G alerkin method (DGM). It involves adaptive choice of the time steps and an isotropic hp-mesh adaptation. The discretization leads to a sequence of la rge algebraic systems which are solved by GMRES method with domain decompo sition based preconditioners.\nParticularly\, we focus on two-level additi ve and hybrid Schwarz techniques which can be easily treated in the contex t of DGM. We study the convergence of the linear solver in dependence on t he number of subdomains and the number of element of the coarse grid. We p ropose a simplified cost model measuring the computational costs in terms of floating-point operations\, the speed of computation\, and the wall-clo ck time for communications among computer cores. Moreover\, the cost model serves as a base of the presented adaptive domain decomposition method wh ich choose the number of subdomains and the number of element of the coars e grid in order to minimize the computational costs. The efficiency of the proposed technique is demonstrated by two benchmarks of compressible flow simulation.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/51/ END:VEVENT BEGIN:VEVENT SUMMARY:Jakub Cach DTSTART:20260304T080000Z DTEND:20260304T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/52 DESCRIPTION:Title: A thermodynamically consistent Johnson-Segalman-Giesekus model: nu merical simulation of the rod climbing effect\nby Jakub Cach as part o f Modelling of materials - theory\, model reduction and efficient numerica l methods (UNCE MathMAC)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/52/ END:VEVENT BEGIN:VEVENT SUMMARY:Vít Průša DTSTART:20260311T080000Z DTEND:20260311T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/53 DESCRIPTION:Title: Discrete versus continuous-linear lattice models and their exact c ontinuous counterparts\nby Vít Průša as part of Modelling of materi als - theory\, model reduction and efficient numerical methods (UNCE MathM AC)\n\n\nAbstract\nWe discuss the correspondence between discrete linear l attice/chain models of interacting particles and their continuous counterp arts represented by linear partial differential equations. In particular\, we study the correspondence problem for linear nearest neighbour interact ion lattice models as well as for linear multiple-neighbour interaction la ttice models\, while we gradually proceed from infinite lattices to period ic lattices and finally to finite lattices with fixed ends/zero Dirichlet boundary conditions. The whole study is framed as a systematic specialisat ion of Fourier analysis tools from the continuous to the discrete setting and vice versa\, and the correspondence between the discrete and continuou s models is examined primarily with regard to the dispersion relation.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/53/ END:VEVENT BEGIN:VEVENT SUMMARY:Eduard Feireisl DTSTART:20260318T080000Z DTEND:20260318T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/54 DESCRIPTION:Title: Well posedness of the Euler system of gas dynamics\nby Eduard Feireisl as part of Modelling of materials - theory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nWe discuss the w ell posedness of the Euler system of gas dynamics from two different perpe ctives:\n1. Admissible solutions are inviscid limits of the Navier-Stokes- Fourier system.\n2. Admissible solutions comply with the maximum entropy p roduction principle.\nWe show that these two criteria are in general not c ompatible and give rise to different classes of solutions.\n\nThen we prop ose and admissibility criterion that gives rise to a unique solution semig roup of the Euler system in the class of generalized dissipative solutions . The solutions are Borel measurable meaning ``almost'' continuous with re spect to the initial data.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/54/ END:VEVENT BEGIN:VEVENT SUMMARY:Kaibo Hu DTSTART:20260325T080000Z DTEND:20260325T090000Z DTSTAMP:20260404T093358Z UID:MathMAC/55 DESCRIPTION:Title: Modelling Generalized Continua with Homological Algebra\nby Ka ibo Hu as part of Modelling of materials - theory\, model reduction and ef ficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nStructure-preservi ng discretization within the frameworks of Finite Element Exterior Calculu s (FEEC) and Finite Element Tensor Calculus (FETC) motivates the investiga tion of the differential structures underlying physical models\, namely\, the spaces in which variables reside and the differential operators that c onnect them. These structures are encoded in differential complexes and th eir associated cohomology. In computational electromagnetism\, discretizin g the entire differential complex avoids spurious solutions and yields man y desirable properties.\n\nRecent efforts to extend this perspective to co ntinuum mechanics have also led to progress in modelling. In elasticity\, strain and stress tensors fit naturally into the elasticity (Calabi\, Krö ner) complex\, which can be viewed as a special case of the Bernstein–Ge lfand–Gelfand (BGG) construction. The intermediate steps in the BGG cons truction turn out to correspond to continuum microstructures\, such as the Cosserat model. From this viewpoint\, the BGG construction can be interpr eted as a cohomology-preserving elimination of microstructural degrees of freedom.\n\nIn this talk\, we explore mechanical models\, such as classica l elasticity\, the Cosserat model\, various plate models (dimension reduct ion)\, continuum defects\, and mixed-dimensional models\, through the lens of differential complexes\, the BGG machinery\, and the Čech complex.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/55/ END:VEVENT BEGIN:VEVENT SUMMARY:Jelena Radovič DTSTART:20260401T070000Z DTEND:20260401T080000Z DTSTAMP:20260404T093358Z UID:MathMAC/56 DESCRIPTION:Title: High-resolution street-scale modeling with LES models\nby Jele na Radovič as part of Modelling of materials - theory\, model reduction a nd efficient numerical methods (UNCE MathMAC)\n\n\nAbstract\nAs the sustai nability implementation requirements at the urban level are far-reaching d ue to extreme weather and climate events\, the need for adequate\, efficie nt\, and high-fidelity modelling tools also increases. Cities lack the res ilience to withstand extreme events\, and the vulnerability of urban dwell ers is elevated. Today\, air quality and thermal comfort deterioration in urban environments are central concerns that shape mitigation policies and urban climate research. However\, finding an appropriate way to understan d the local urban atmosphere\, recognise issues\, and produce reliable inf ormation and solutions is complex and multibranched. It requires not only high-end numerical tools\, software\, observation networks\, and urban dat asets\, but also careful planning\, interpretation\, and cooperation betwe en the expert community and public administration.\n\nThe cornerstone of a ny scientific investigation of certain phenomena lies in understanding the physical processes that drive them and govern their evolution. The physic al framework of the urban boundary layer is a delicate balance of various physical processes that affect the urban atmosphere\, airflow\, and phenom ena within it. This framework is simultaneously influenced by urban morpho logy and the specificity of settlement patterns. Despite being distinctive on a broader scale\, urban areas share a common trait of being heterogene ous with a range of artificial and natural surfaces covering them. Along w ith large-scale atmospheric dynamics\, human activities\, etc.\, these tra its make cities hotbeds for turbulence generation. Turbulence is a governi ng mechanism shaping urban atmospheric behaviour\, energy balance\, pollut ant transport\, and street-scale airflow dynamics. It is certainly fundame ntal and needs to be adequately resolved\, with its influence on the urban atmospheric processes accurately represented in the models. Resolving the urban morphology and the boundary layer on a fine scale via numerical mod els is a prerequisite for understanding urban ventilation\, air quality\, and thermal comfort and progressing in climate change adaptation and mitig ation.\n\nThis presentation addresses these critical urban climate issues by utilising Large-Eddy Simulation (LES) to achieve high-resolution\, stre et-scale modelling. The Parallelized Large-Eddy Simulation Model (PALM)\, a state-of-the-art computational framework designed specifically for the u rban canopy is introduced. The presentation will detail PALM’s advanced capabilities\, including its sophisticated treatment of urban surfaces\, p lant canopy effects\, and high-resolution turbulence resolving features.\n LOCATION:https://stable.researchseminars.org/talk/MathMAC/56/ END:VEVENT END:VCALENDAR