0585697 - ÚH 2025 RIV CZ eng C - Conference Paper (international conference)
Gebouský, Ondřej - Haidl, Jan - Bodnár, J. - Pivokonský, Martin
Improvement of an unbaffled stirred tank mixing characteristics using variable speed impeller.
Topical Problems of Fluid Mechanics. Prague: Institute of Thermomechanics AS CR, v. v. i., 2024 - (Šimurda, D.; Bodnár, T.), s. 54-60. ISBN 978-80-87012-88-8. ISSN 2336-5781.
[Topical Problems of Fluid Mechanics 2024. Prague (CZ), 21.02.2024-23.02.2024]
Grant - others:AV ČR(CZ) StrategieAV21/20; AV ČR(CZ) AP2201
Program: StrategieAV; Akademická prémie - Praemium Academiae
Institutional support: RVO:67985874
Keywords : unbaffled mixing tanks * variable rotational speed * vortex destabilization * mixing time improvement
OECD category: Chemical engineering (plants, products)
http://www2.it.cas.cz/fm/im/im/proceeding/2024/8

Unbaffled mixing tanks with magnetically driven impellers are increasingly used in biotechnological and pharmaceutical industries, combining the benefits of a closed, sterile environment with easy equipment cleanability. On the other hand, missing internals, such as baffles or cooling coils, have an adverse effect on the equipment mixing characteristics, namely the batch
homogenization time. In our previous research, we uncovered that the eccentricity and inclination of the impeller – both employed routinely to enhance the mixing characteristics of unbaffled vessels – are not fully effective in the suppression of central vortex formation resulting in the increase in the homogenization time. In this work, we propose a simple solution to counteract the central vortex formation – a periodical variation of impeller rotational speed. This approach destabilizes the central vortex, significantly reducing homogenization time while maintaining the benefits of the original unbaffled setup. This innovation can seamlessly integrate into existing industrial setups, promising efficiency gains for biotech and pharmaceutical production.
Permanent Link: https://hdl.handle.net/11104/0353398

 

0587326 - ÚH 2025 DE ger C - Conference Paper (international conference)
Hofbauer, Michael - Šípek, Václav - Dvořák, P.
Untersuchungen zu Langzeiteffekten des Ökolandbaus auf die Speicherung pflanzenverfügbaren Bodenwassers.
[A study of long-term effects of organic agriculture on the retention of plant available soil water.]
Proceedings of 17. Wissenschaftstagung Ökologischer Landbau. Frankfurt am Main: Forschungsinstitut für biologischen Landbau FiBL Deutschland, 2024 - (Bruder, V.; Röder-Dreher, U.; Herzig, C.; Gattinger, A.), s. 392-393
[17. Wissenschaftstagung Ökologischer Landbau, Landwirtschaft und Ernährung – Transformation macht nur gemeinsam Sinn. Giessen (DE), 05.03.2024-08.03.2024]
Institutional support: RVO:67985874
Keywords : soil water * system comaprison * climate change * Czech Republic
OECD category: Agriculture
https://orgprints.org/id/eprint/53471/

A study of the retention of plant available soil water after 15 years of recognised organic management was launched in 2023 in the Czech Republic. Soil water retention, saturated hydraulic conductivity, origin of soil water, volumetric soil water content and soil organic carbon content are determined several times throughout two years and compared between organic management and conventional management. The project results are expected to indicate whether organic farming leads to a better soil water retention compared to conventional farming.
Permanent Link: https://hdl.handle.net/11104/0355615

 

0585700 - ÚH 2025 RIV CZ eng C - Conference Paper (international conference)
Idžakovičová, Kristýna - Bílek, Vojtěch - Haidl, Jan - Isoz, M. - Pivokonský, Martin
Flow simulations approach for flocculation tanks.
Topical Problems of Fluid Mechanics. Prague: Institute of Thermomechanics AS CR, v. v. i., 2024 - (Šimurda, D.; Bodnár, T.), s. 77-84. ISBN 978-80-87012-88-8. ISSN 2336-5781.
[Topical Problems of Fluid Mechanics 2024. Prague (CZ), 21.02.2024-23.02.2024]
Grant - others:AV ČR(CZ) StrategieAV21/20; AV ČR(CZ) AP2201
Program: StrategieAV; Akademická prémie - Praemium Academiae
Institutional support: RVO:67985874
Keywords : flocculation tank * stirring * MRF * CFD * OpenFOAM
OECD category: Chemical engineering (plants, products)
http://www2.it.cas.cz/fm/im/im/proceeding/2024/11

Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and savings of operational costs. However, it is currently based on trial-and-error experimental approaches. In this contribution, we focus on flow modeling in stirred flocculation tanks that would, after coupling with a calibrated model of particle aggregation, enable simulationbased flocculation optimization. Despite the abundance of literature on stirred tank modeling, there is no universal agreement on the methodology used to describe turbulence nor on the approach to the computational mesh creation. Consequently, there is no unified methodology for simulations and their validation. To address this, we present a best-practice methodology for economical, yet reliable flow simulations in the said device. This methodology includes the choice of the turbulence model, the approach to the design of a high quality mesh suitable for arbitrary geometries, and results evaluation. It is developed based on an extensive literature review, a multitude of flow simulations using several meshes of progressively higher quality and resolution, and various strategies to converge to steady-state flow conditions. The simulation quality indicators used here involve comparison with the experimental data on fluid velocity, stirrer power output, and flow rate through the impeller zone. Additionally, the resulting flow simulation models are compared using tracer transport simulations, hinting at their potential for coupling with particle aggregation models.
Permanent Link: https://hdl.handle.net/11104/0353403

 

0598267 - ÚH 2025 RIV NL eng J - Journal Article
Langhammer, J. - Lendzioch, T. - Vlček, Lukáš
Montane peatland response to drought: Evidence from multispectral and thermal UAS monitoring.
Ecological Indicators. Roč. 167, October (2024), č. článku 112587. ISSN 1470-160X. E-ISSN 1872-7034
Institutional support: RVO:67985874
Keywords : peatlands * climate change * drought * UAS * land surface temperature * soil moisture
OECD category: Hydrology
Impact factor: 7, year: 2023
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S1470160X24010446

This paper investigates the response of mid-latitude montane peatlands to climate warming, focusing on changes occurring in a montane peat bog during a drought period. Unmanned Aerial Systems (UAS) equipped with multispectral and thermal sensors were used for high-resolution monitoring to analyze qualitative changes within the peat bog and their spatial distribution. The study was conducted in the Rokytka mountain peat bog in Šumava National Park, Czech Republic, which is one of the largest mountain peat bog complexes in Central Europe. Monitoring took place during the 2019 vegetation season, coinciding with the peak of the 2015–2019 drought. The recurrent UAS imaging campaigns were complemented by continuous hydrological and hydropedological monitoring and in-situ calibration measurements. The findings revealed diverging responses of montane peatlands to climate change across different functional zones of the peat bog. UAS thermal mapping identified distinct land surface temperature variations across various vegetation categories under different conditions. Notably, ponds and waterlogged areas displayed a stabilizing effect on land surface temperature variability, though they exhibited different absolute temperatures. In contrast, shallow waterlogged areas exhibited surface temperatures akin to dry open peat areas. Multispectral UAS monitoring demonstrated significant transitions among the peat bog zones in response to heat and drought propagation. The most pronounced changes occurred in shallow waterlogged areas, which shrank notably from 22.8% to 4.5%, while bare peat expanded from 26.8% to 45.5% during the 2019 drought season. High-resolution thermal and multispectral monitoring has revealed the scope and magnitude of the intra-peatland responses to drought and heat waves and serves as a sensible indicator of environmental changes of peatlands. It has disclosed a large cumulative effect of change in an environment composed of highly heterogeneous and subtle structures. The results highlighted the effectiveness of UAS monitoring in understanding the extent of change in montane peatlands as a fragile environment exposed to the effects of climate change.
Permanent Link: https://hdl.handle.net/11104/0355992

 

0586413 - ÚIACH 2025 CZ eng A - Abstract
Matoušek, Tomáš - García-Figueroa, Adrián - Prokopová, Michaela - Pivokonský, Martin - Musil, Stanislav - Filella, M.
Speciation of arsenic, antimony, germanium and tellurium in drinking water reservoirs over the seasons of the year.
CSSC & MSMS 2024 book of abstracts. Praha: Spektroskopická společnost Jana Marka Marci, 2024 - (Holá, M.; Kanický, V.; Machala, L.; Matějka, P.; Sobek, K.; Vaculovič, T.; Vašina, T.). s. 59-59. ISBN 978-80-88195-54-2.
[Czech-Slovak Spectroscopic Conference (CSSC) /18./ & Mössbauer Spectroscopy in Materials Science (MSMS). 27.05.2024-31.05.2024, Kurdějov]
R&D Projects: GA ČR(CZ) GA23-06530S
Grant - others:AV ČR(CZ) StrategieAV21/20
Program: StrategieAV
Institutional support: RVO:68081715 ; RVO:67985874
Keywords : speciation * hydride generation * inductively coupled plasma mass spectrometry
OECD category: Analytical chemistry
https://cssc2024.spektroskopie.cz/files/BoA_final.pdf

The lecture presented analytical method for speciation analysis of As, Sb, Ge and Te in natural waters, and the concentrations of specises of these elements in depth profiles of Vrchlice nad Souš drinking water reservoirs over various seasons of the year.
Permanent Link: https://hdl.handle.net/11104/0353950