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Finite element modal analysis of a silicone vocal fold filled with fluid
Hájek, P.; Radolf, Vojtěch; Horáček, Jaromír; Švec, J. G.
2023 - English
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the continuum mechanics and consider large deformations. The fluid domain encapsulated in the silicone VF is defined semianalytically as a lumped-element model describing the fluid in hydrostatic conditions. The elongated and pressurized silicone VF was subjected to perturbed modal analysis. Results showed that the choice of the fluid inside the VF substantially influences the natural frequencies. Namely, the water-filling lowers the natural frequencies approximately by half over the air-filling. Besides, the procedure of reverse engineering for obtaining the geometry of the VF from already 3D-printed mold is introduced.
Keywords:
perturbed modal analysis; finite element method; vocal folds; reverse engineering; biomechanics of voice
Fulltext is available at external website.
Finite element modal analysis of a silicone vocal fold filled with fluid
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the ...
Key barriers, opportunities and good practices for entrepreneurship and innovation
Křížková, Alena; Marková Volejníčková, Romana; Pospíšilová, Marie; Vohlídalová, Marta
2023 - English
The report is focused on barriers, opportunities and good practices for gender-sensitive innovations and entrepreneurship. It is based on the analysis of 36 interviews with experts from the health, green and digital fields and the target groups defined in the quadruple helix of academia, citizens, industry, and government. The interviews were collected by 12 GILL partners in the 10 consortium countries in 2023. Gender stereotypical cultural beliefs and norms, masculine bias, gender segregation, lack of funding, lack of policies to support work-life balance and lack of political will and empirical evidence to remove these barriers are the main problems identified. The opportunities reflected largely correspond to these barriers and highlight the role of key actors, such as the EU, in setting standards. Projects focusing on fixing the number of women under-represented in certain fields and occupations and management positions predominate among good practices.
Keywords:
.gender equality; gender in entrepreneurship; gender in science; gender in innovation; gender stereotypes; good practices
Available in digital repository of the ASCR
Key barriers, opportunities and good practices for entrepreneurship and innovation
The report is focused on barriers, opportunities and good practices for gender-sensitive innovations and entrepreneurship. It is based on the analysis of 36 interviews with experts from the health, ...
From John Graunt to Adolphe Quetelet: on the Origins Of Demography
Kalina, Jan
2023 - English
John Graunt (1620-1674) and Adolphe Quetelet (1796-1874) were two important personalities, who contributed to the origins of demography. As they both developed statistical techniques for the analysis of demographic data, they are important also from the point of view of history of statistics. The contributions of both Graunt and Quetelet especially to the development of mortality tables and models are recalled in this paper. Already from the 17th century, the available mortality tables were exploited for computing life annuities. Also the contribution of selected personalities inspired by Graunt are recalled here, the work of Christian Huygens, Jacob Bernoulli, or Abraham de Moivre is discussed to document that the historical development of statistics and probability theory was connected with the development of demography.
Keywords:
history of demography; history of statistics; probability theory; moral statistics; mortality tables
Fulltext is available at external website.
From John Graunt to Adolphe Quetelet: on the Origins Of Demography
John Graunt (1620-1674) and Adolphe Quetelet (1796-1874) were two important personalities, who contributed to the origins of demography. As they both developed statistical techniques for the analysis ...
MAD UFOs: Magnetically Arrested Discs with persistent Ultra-Fast Outflows
Suková, Petra; Zajaček, M.; Karas, Vladimír
2023 - English
We study an outflow that develops in the MAD state in 3D GRMHD simulations. We show that the outflow can be accelerated to\nrelativistic velocities and persist over the course of our simulation. We compare the properties of the outflow from MAD discs with those launched by orbiting secondary at close orbit. The main difference is that the orbiting body launches a more coherent, quasiperiodic ultrafast outflow at lower velocities (v < 0.5c) while the outflow launched in the MAD state (without the body) has a stochastic behaviour and has anapproximately flat velocity distribution between lower anf higher outflow velocities, 0.2c < v < 0.3c and v > 0.5c.
Keywords:
accretion discs; black holes; active galactic nuclei
Fulltext is available at external website.
MAD UFOs: Magnetically Arrested Discs with persistent Ultra-Fast Outflows
We study an outflow that develops in the MAD state in 3D GRMHD simulations. We show that the outflow can be accelerated to\nrelativistic velocities and persist over the course of our simulation. We ...
TESTING THE METHOD OF MULTIPLE SCALES AND THE AVERAGING PRINCIPLE FOR MODEL PARAMETER ESTIMATION OF QUASIPERIODIC TWO TIME-SCALE MODELS
Papáček, Štěpán; Matonoha, Ctirad
2023 - English
Some dynamical systems are characterized by more than one timescale, e.g. two well separated time-scales are typical for quasiperiodic systems. The aim of this paper is to show how singular perturbation methods based on the slow-fast decomposition can serve for an enhanced parameter estimation when the slowly changing features are rigorously treated. Although the ultimate goal is to reduce the standard error for the estimated parameters, here we test two methods for numerical approximations of the solution of associated forward problem: (i) the multiple time-scales method, and (ii) the method of averaging. On a case study, being an under-damped harmonic oscillator containing two state variables and two parameters, the method of averaging gives well (theoretically predicted) results, while the use of multiple time-scales method is not suitable for our purposes.
Keywords:
Dynamical system; Singular perturbation; Averaging; Parameter estimation; Slow-fast decomposition; Damped oscillations
Fulltext is available at external website.
TESTING THE METHOD OF MULTIPLE SCALES AND THE AVERAGING PRINCIPLE FOR MODEL PARAMETER ESTIMATION OF QUASIPERIODIC TWO TIME-SCALE MODELS
Some dynamical systems are characterized by more than one timescale, e.g. two well separated time-scales are typical for quasiperiodic systems. The aim of this paper is to show how singular ...
Inflation expectations in the wake of the war in Ukraine
Afunts, Geghetsik; Cato, M.; Schmidt, T.
2023 - English
Russia's invasion of Ukraine is posing a range of new challenges to the global economy, including affecting the inflation expectations of individuals. In this paper, we aim to quantify the effect of the invasion on short- and long-term inflation expectations of individuals in Germany. We use microdata from the Bundesbank Online Panel - Households (BOP-HH), for the period from February 15th to March 29th, 2022. Treating the unanticipated start of the war in Ukraine on the 24th of February 2022 as a natural experiment, we find that both short- and long-term inflation expectations increased as an immediate result of the invasion. Long-term inflation expectations increased by around 0.4 percentage points, while the impact on short-term inflation expectations was more than twice as large - around one percentage point. Looking into the possible mechanisms of this increase, we suggest that it can be partially attributed to individuals’ fears of soaring energy prices and increasing pessimism about economic trends in general. Our results indicate that large economic shocks can have a substantial impact on both short and long-term inflation expectations.
Keywords:
inflation expectations; Russian invasion of Ukraine; survey
Fulltext is available at external website.
Inflation expectations in the wake of the war in Ukraine
Russia's invasion of Ukraine is posing a range of new challenges to the global economy, including affecting the inflation expectations of individuals. In this paper, we aim to quantify the effect of ...
Different Boundary Conditions For LES Solver PALM 6.0 Used for ABL in Tunnel Experiment
Řezníček, Hynek; Geletič, Jan; Bureš, Martin; Krč, Pavel; Resler, Jaroslav; Vrbová, Kateřina; Trush, Arsenii; Michálek, Petr; Beneš, L.; Sühring, M.
2023 - English
We tried to reproduce results measured in the wind tunnel experiment with a CFD simulation provided by numerical model PALM. A realistic buildings layout from the Prague-Dejvice quarter has been chosen as a testing domain because solid validation campaign for PALM simulation of Atmospheric Boundary Layer (ABL) over this quarter was documented in the past. The question of input data needed for such simulation and capability of the model to capture correctly the inlet profile and its turbulence structure provided by the wind-tunnel is discussed in the study The PALM dynamical core contains a solver for the Navier-Stokes equations. By default, the model uses the Large Eddy Simulation (LES) approach in which the bulk of the turbulent motions is explicitly resolved. It is well validated tool for simulations of the complex air-flow within the real urban canopy and also within its reduced scale provided by wind tunnel experiments. However the computed flow field between the testing buildings did not correspond well to the measured wind velocity in some points. Different setting of the inlet boundary condition was tested but none of them gave completely developed turbulent flow generated by vortex generators and castellated barrier wall place at the entrance of the aerodynamic section of the wind tunnel.
Keywords:
large eddy simulation; wind tunnel; atmospheric boundary layer; PALM model; turbulence
Fulltext is available at external website.
Different Boundary Conditions For LES Solver PALM 6.0 Used for ABL in Tunnel Experiment
We tried to reproduce results measured in the wind tunnel experiment with a CFD simulation provided by numerical model PALM. A realistic buildings layout from the Prague-Dejvice quarter has been ...
Ambiguity in Stochastic Optimization Problems with Nonlinear Dependence on a Probability Measure via Wasserstein Metric
Kaňková, Vlasta
2023 - English
Many economic and financial applications lead to deterministic optimization problems depending on a probability measure. It happens very often (in applications) that these problems have to be solved on the data base. Point estimates of an optimal value and estimates of an optimal solutionset can be obtained by this approach. A consistency, a rate of convergence and normal properties, of these estimates, have been discussed (many times) not only under assumptions of independent data corresponding to the distributions with light tails, but also for weak dependent data and the distributions with heavy tails. However, it is also possible to estimate (on the data base) a confidence intervals and bounds for the optimal value and the optimal solutions. To analyze this approach we focus on a special case of static problems depending nonlineary on the probability measure. Stability results based on the Wasserstein metric and the Valander approach will be employed for the above mentioned analysis.
Keywords:
Stochastic optimization problems; static problems; empirical measure; point estimates; interval estimates; nonlinear dependence
Fulltext is available at external website.
Ambiguity in Stochastic Optimization Problems with Nonlinear Dependence on a Probability Measure via Wasserstein Metric
Many economic and financial applications lead to deterministic optimization problems depending on a probability measure. It happens very often (in applications) that these problems have to be solved ...
Improving computational efficiency of contact solution in fully resolved CFD-DEM simulations with arbitrarily-shaped solids
Studeník, Ondřej; Kotouč Šourek, M.; Isoz, Martin
2023 - English
The abundance of industrial processes containing both solid and liquid phases generate demand for fully resolved models allowing for detailed analysis and optimization of these processes. An established approach providing such models is based using a variant of an immersed boundary method to couple the computational fluid dynamics (CFD) and discrete element method (DEM). In the talk, we will present our custom and monolithic implementation of a fully-resolved CFDDEM solver and concentrate on the intricacies of solving contact between two arbitrarily-shaped solids. We shall propose an efficient contact treatment based on the concept of a virtual mesh, which provides the mesh resolution required by DEM through dividing the space around the contact point in a finite volume fashion without any changes to the CFD mesh itself. A substantial part of the talk will devoted to the parallelization of the contact solution, especially in the context of the domain decomposition method imposed by the CFD solver.
Keywords:
CFD; DEM; virtual mesh
Fulltext is available at external website.
Improving computational efficiency of contact solution in fully resolved CFD-DEM simulations with arbitrarily-shaped solids
The abundance of industrial processes containing both solid and liquid phases generate demand for fully resolved models allowing for detailed analysis and optimization of these processes. An ...
Hazardous components: A case study in textile waste management
Shtukaturova, Anastasia
2023 - English
Textile waste, a problem that has been somewhat overlooked for many years, is now coming to the fore.1 The textile value chain is long\nand complex, with over 8000 chemicals used in different manufacturing processes.2 A wide variety of chemicals are used in the manufacture of textile products for the improvement of essential properties and performance of textiles. Chemicals used in textiles significantly improve their quality and appearance. However, the harmful effects of these chemicals can occur at various stages of textile production and processing, such as dyeing, printing and finishing, as well as during use by consumers and at the end-of-life stage.3 There is a lack of safety information on the presence and use of all of these chemicals in consumer products.
Keywords:
textile waste; waste management; chemicals
Available in a digital repository NRGL
Hazardous components: A case study in textile waste management
Textile waste, a problem that has been somewhat overlooked for many years, is now coming to the fore.1 The textile value chain is long\nand complex, with over 8000 chemicals used in different ...
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