Numerical evaluation of mass-diffusive compressible fluids flows models
Bodnár, Tomáš; Fraunié, P.
2024 - English
This contribution presents first numerical tests of some recently published alternative models for solution of viscous compressible and nearly incompressible models. All models are solved by high resolution compact finite difference scheme with strong stability preserving RungeKutta time stepping. The two simple but challenging computational test cases are presented, based on the double-periodic shear layer and the Kelvin-Helmholtz instability. The obtained time-dependent flow fields are showing pronounced shear and vorticity layers being resolved by the standard as well as by the new mass-diffusive modified models. The preliminary results show that the new models are viable alternative to the well established classical models.
Keywords:
compressible Navier-Stokes; nearly incompressible flow; mass diffusion; compact finite-difference
Available in digital repository of the ASCR
Numerical evaluation of mass-diffusive compressible fluids flows models
This contribution presents first numerical tests of some recently published alternative models for solution of viscous compressible and nearly incompressible models. All models are solved by high ...
Motion of fluids in the moving domain
Nečasová, Šárka
2024 - English
It is a survay paper where the problem of the existence of weak solutions of compressible barotropic solutions in a moving bounded domain is studied.
Keywords:
compressible fluid; moving domain; weak solutions
Available in digital repository of the ASCR
Motion of fluids in the moving domain
It is a survay paper where the problem of the existence of weak solutions of compressible barotropic solutions in a moving bounded domain is studied.
Financial skills and search in the mortgage market
Cota, Marta; Šterc, Ante
2024 - English
Are households with low financial skills disadvantaged in the mortgage market? Using stochastic record linking, we construct a unique U.S. dataset encompassing a rich set of mortgage details and borrowers’ characteristics, including their objective financial literacy measure. We find that households with low financial literacy are up to 4% more likely to search less and lock in at 15-20 b.p. higher rates. Upon origination, unskilled borrowers face a 35-45% higher mortgage delinquency and end up with a 30% lower likelihood of refinancing. Overall, for a $100,000 loan, the potential losses from low financial literacy are more than $9,329 over the mortgage duration. To understand how financial education, more accessible mortgages, or mortgage rate changes affect households with low financial literacy, we formulate and calibrate a mortgage search model with heterogeneous search frictions and endogenous financial skills. Our model estimates show that search intensity and financial skill variations contribute to 55% and 10% of mortgage rate variations, respectively. We find that i) more accessible mortgages lead to a higher delinquency risk among low-skilled households, ii) financial education mitigates the adverse effects of increased accessibility, and iii) low mortgage rates favor high-skilled homeowners and, by reinforcing refinancing activity, deepen consumption differences across different financial skill levels.
Keywords:
mortgage refinancing; mortgage search; financial skills
Fulltext is available at external website.
Financial skills and search in the mortgage market
Are households with low financial skills disadvantaged in the mortgage market? Using stochastic record linking, we construct a unique U.S. dataset encompassing a rich set of mortgage details and ...
Stochastic version of the arc-length method
Náprstek, Jiří; Fischer, Cyril
2024 - English
The solution of a nonlinear algebraic system using the incremental method, based on pre-defined loading steps, fails in the vicinity of local extrema as well as around bifurcation points. The solution involved the derivation of the so-called ’Arc-Length’ method. Its essence lies in not incrementing the system parameter or any of the independent variables but rather the length of the response curve. The stochastic variant of this method allows for working with a system where system parameters include random imperfections. This contribution presents a variant that tracks the first two stochastic moments. Even in this simple case, interesting phenomena can be observed, such as the disappearance of the energy barrier against equilibrium jump due to random imperfections in the system.
Keywords:
random imperfection; stochastic arc-length method; continuation; numerical method
Available in digital repository of the ASCR
Stochastic version of the arc-length method
The solution of a nonlinear algebraic system using the incremental method, based on pre-defined loading steps, fails in the vicinity of local extrema as well as around bifurcation points. The solution ...
Acoustic emission methods in steel bridge degradation identification and monitoring
Šorm, Filip
2024 - English
Acoustic emission methods proved to be an effective diagnostic tool in many industrial sectors. The potential of this method in the field of steel bridge diagnostics is explored in this article. The goal is to find the most effective use of this method.
Keywords:
steel bridges; diagnostics; acoustic emission
Available in digital repository of the ASCR
Acoustic emission methods in steel bridge degradation identification and monitoring
Acoustic emission methods proved to be an effective diagnostic tool in many industrial sectors. The potential of this method in the field of steel bridge diagnostics is explored in this article. The ...
Temoporfin-conjugated upconversion nanoparticles for NIR-induced photodynamic therapy of pancreatic cancer
Shapoval, Oleksandr; Větvička, D.; Kabešová, M.; Engstová, Hana; Horák, Daniel
2024 - English
Photodynamic therapy (PDT), a clinically approved cancer treatment strategy, has the potential to cure pancreatic cancer with minimal side effects. PDT primarily uses visible wavelengths to directly activate hydrophobic photosensitizers, which may be insufficient for deep-seated cancer cells in clinical practice due to poor penetration. Upconversion nanoparticles (UCNPs) serve as an indirect excitation source to activate photosensitizers (PSs) in the NIR region, overcoming the limitations of molecular PSs such as hydrophobicity, non-specificity, and excitation in the UV/Vis region. Here, monodisperse upconversion NaYF4:Yb3+, Er3+, Fe2+ nanoparticles (UCNPs) have been surface-engineered with poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) and temoporfin (mTHPC), a clinically used PDT prodrug, for near-infrared (NIR) light-triggered PDT of pancreatic cancer. The incorporation of Fe2+ ions into the particles increased the fluorescence intensity in the red region matching the activation wavelength of mTHPC. Covalent binding of mTHPC to the surface of UCNP@PMVEMA particles provided colloidally stable conjugates enabling generation of singlet oxygen. In vitro cytotoxicity and photodynamic activity of the particles were evaluated using INS-1E rat insulinoma and Capan-2 and PANC-01 human pancreatic adenocarcinoma cell lines. The PDT efficacy of UCNP@PMVEMA-mTHPC conjugates after irradiation with 980 nm NIR light was tested in vivo in a pilot study on Capan-2 human pancreatic adenocarcinoma growing subcutaneously in athymic nude mice. The intratumoral administration of the nanoconjugates significantly hindered tumor growth and demonstrated promising PDT efficacy against human pancreatic cancer.
Keywords:
photodynamic therapy; temoporfin; upconversion nanoparticles
Available in digital repository of the ASCR
Temoporfin-conjugated upconversion nanoparticles for NIR-induced photodynamic therapy of pancreatic cancer
Photodynamic therapy (PDT), a clinically approved cancer treatment strategy, has the potential to cure pancreatic cancer with minimal side effects. PDT primarily uses visible wavelengths to directly ...
Multi-Annual Characterization of PM1 Aerosol Optical Properties and Size Distribution at the Peri-Urban Atmospheric Site ATOLL in Lille
Suchánková, Lenka
2024 - English
The aim of this study is to present aerosol scattering, absorption properties and particle number size distribution in PM1 in years 2018-\n2022 at peri-urban atmospheric site Atmospheric Observations in LiLLE (ATOLL) in Lille, France. This study is the first to present results dedicated to aerosol scattering properties at this site.
Keywords:
aerosol particles; PM1; temporal trends
Available in digital repository of the ASCR
Multi-Annual Characterization of PM1 Aerosol Optical Properties and Size Distribution at the Peri-Urban Atmospheric Site ATOLL in Lille
The aim of this study is to present aerosol scattering, absorption properties and particle number size distribution in PM1 in years 2018-\n2022 at peri-urban atmospheric site Atmospheric Observations ...
Development of Continuous Technology for the Preparation of Pharmaceuticals
Jaklová, Natalie
2024 - English
The present research focuses on the transition of a batch reaction assisted by phase transfer catalyst (PTC) into continuous process. The first reaction studied was an N-alkylation reaction with methyl ester of the 1-methyl-10α-methoxydihydrolysergic acid (MeLUME) as product. MeLUME is one of the intermediates in synthesis of drug Nicergoline. The N-alkylation occurs in two different immiscible phases and the bridge between these phases is the phase transfer catalyst. The study was performed in several different continuous flow apparatuses. The best results were obtained in a capillary reactor, with assistance of ultrasound.
Keywords:
continualization; ultrasound; pharmaceuticals
Available in a digital repository NRGL
Development of Continuous Technology for the Preparation of Pharmaceuticals
The present research focuses on the transition of a batch reaction assisted by phase transfer catalyst (PTC) into continuous process. The first reaction studied was an N-alkylation reaction with ...
Bubble Breakup in Triton Solutions
Semlerová, Tereza
2024 - English
This work deals with investigation of the bubble breakup in surfactant Triton X-45 solutions and the results are compared with data measured in water and α-terpineol solutions as another type of surfactants.
Keywords:
bubble breakup; surfactants; dynamic surface tension
Available in digital repository of the ASCR
Bubble Breakup in Triton Solutions
This work deals with investigation of the bubble breakup in surfactant Triton X-45 solutions and the results are compared with data measured in water and α-terpineol solutions as another type of ...
Thin Film Photocatalysts on the Basis of g-C3N4
Schimon, Domonik
2024 - English
This study revolves around the synthesis of powder g-C3N4, fabricationof thin g-C3N4 films and their efficacy in degrading pollutants, assessed through experimentation in a batch photoreactor (BPR) and a slit geometry photomicroreactor (PMR)2. The photocatalytic activity of g-C3N4 was tested with 4 different model substances: fluorescent dye, rhodamine B, was used as a reference substance and three separate antibiotics, which are emerging wastewater pollutants, namely tetracycline, trimethoprim, sulfamethoxazole.
Keywords:
g-C3N4; photocatalysis; microreactor
Available in a digital repository NRGL
Thin Film Photocatalysts on the Basis of g-C3N4
This study revolves around the synthesis of powder g-C3N4, fabricationof thin g-C3N4 films and their efficacy in degrading pollutants, assessed through experimentation in a batch photoreactor (BPR) ...
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