No (9942)
Yes (1923)
Number of found documents:
11865
Published from
to
Development of Polymeric Enantioselective Membranes
Čížek, Jan
2024 - English
Enantiomers are molecules that share the same chemical formula but in space form mirror images of each other. Their reactions with other chiral molecules can be remarkably different, which is crucial mainly for pharmaceuticals and agrochemicals. However, industrialscale synthetic production of enantiomerically pure compounds is not always available. Therefore, the need for pure enantiomeric compounds drives the development and research on various separation methods. However, most methods used on the industrial scale are limited to specific compounds (diastereomeric recrystallization) or generally difficult and/or expensive to scale up (chromatography-related methods). Separation of enantiomers using membranes is promising\nthanks to the easy scalability and continuous operation of membrane processes. Various ideas about how the enantioselective membranes should look like have been published in the last thirty years. The mechanism of enantiomeric separation on a membrane is, however, highly specific, and still requires extensive research. In this work, four types of enantioselective polymeric membranes are presented.
Available in a digital repository NRGL
Development of Polymeric Enantioselective Membranes
Enantiomers are molecules that share the same chemical formula but in space form mirror images of each other. Their reactions with other chiral molecules can be remarkably different, which is crucial ...
Synthesis of Fluorinated Methyl β-Lactosides
Krčil, Aleš
2024 - English
In my contribution, I will describe the synthesis of a complete series of mono-deoxyfluorinated methyl β-lactosides (1–7). Their affinity towards hgals will be determined by analytical method ELISA. The synthesis relies on monosaccharide building blocks, which serves as key intermediates that are transformed into the target products through glycosylation followed by final deprotection steps.
Keywords:
flurinated carbohydrates; galectin; deoxyfluorination
Available in a digital repository NRGL
Synthesis of Fluorinated Methyl β-Lactosides
In my contribution, I will describe the synthesis of a complete series of mono-deoxyfluorinated methyl β-lactosides (1–7). Their affinity towards hgals will be determined by analytical method ELISA. ...
Investigation of Mechanical Processing of Solar Photovoltaic Panels
Šperlich, Antonín
2024 - English
This work aims to describe the possibilities of mechanical treatment of solar photovoltaic panels. In the first part, the shredding and milling process for the transformation of the product (whole panel) into material that can be further processed, was investigated. Milled material was sieved and analyzed. It was observed that this shredding also works as a selective grinding because three main products were produced. The second part of this work was aimed at the physical concentration of silver in real samples of milled solar photovoltaic panels by Knelson separator. This device (type of centrifugal separator) showed the ability to significantly increase the amount of silver in the outcome stream.
Keywords:
solar photovoltaic panels; selective milling; Knelson
Available in a digital repository NRGL
Investigation of Mechanical Processing of Solar Photovoltaic Panels
This work aims to describe the possibilities of mechanical treatment of solar photovoltaic panels. In the first part, the shredding and milling process for the transformation of the product (whole ...
Axial Dispersion and Mass Transfer in Bubble Column
Terentyak, Mark
2024 - English
The objective of the study is to experimentally investigate axial dispersion and mass transfer within a bubble column, examining their mutual interrelation\nand their correlation with operational parameters and AR1.
Keywords:
bubble column; axial dispersion; mass transfer
Available in a digital repository NRGL
Axial Dispersion and Mass Transfer in Bubble Column
The objective of the study is to experimentally investigate axial dispersion and mass transfer within a bubble column, examining their mutual interrelation\nand their correlation with operational ...
Exploring Bubble Dynamics with VOF Method Simulations: Insights from Two Fundamental Gas-Liquid Flow Case Studies
Harrandt, Václav
2024 - English
The present study focuses on the flow of Taylor bubbles, representing the interaction between the channel wall and the gas phase, and the collision of\na bubble with a vortex ring, serving as a model liquid-gas interaction. Understanding the former case can be essential to prevent the membrane\nfouling or the flow induced corrosion. The dynamics of the latter case is the predictive criterion for whether the initial mother bubble will break up into the daughter bubbles or not2 and this process can therefore be used as an idealized model of turbulent bubble flow.
Keywords:
bubble dynamics; multiphase interaction,; numerical simulation
Available in a digital repository NRGL
Exploring Bubble Dynamics with VOF Method Simulations: Insights from Two Fundamental Gas-Liquid Flow Case Studies
The present study focuses on the flow of Taylor bubbles, representing the interaction between the channel wall and the gas phase, and the collision of\na bubble with a vortex ring, serving as a model ...
Flow simulations approach for flocculation tanks
Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
2024 - English
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.
Keywords:
flocculation tank; stirring; MRF; CFD; OpenFOAM
Available at various institutes of the ASCR
Flow simulations approach for flocculation tanks
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 ...
Improvement of an unbaffled stirred tank mixing characteristics using variable speed impeller
Gebouský, Ondřej; Haidl, Jan; Bodnár, J.; Pivokonský, Martin
2024 - English
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\nhomogenization 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.
Keywords:
unbaffled mixing tanks; variable rotational speed; vortex destabilization; mixing time improvement
Available in digital repository of the ASCR
Improvement of an unbaffled stirred tank mixing characteristics using variable speed impeller
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 ...
Finite element approximation of fluid structure interaction using Taylor-Hood and Scott-Vogelius elements
Vacek, Karel; Sváček, P.
2024 - English
This paper addresses the problem of fluid flow interacting a vibrating solid cylinder described by one degree of freedom system and with fixed airfoil. The problem is described by the incompressible Navier-Stokes equations written in the arbitrary Eulerian-Lagrangian (ALE) formulation. The ALE mapping is constructed with the use of a pseudo-elastic approach. The flow problem is numerically approximated by the finite element method (FEM). For discretization of the fluid flow, the results obtained by both the Taylor-Hood (TH) element and the Scott-Vogelius (SV) finite element are compared. The TH element satisfies the Babuška-Brezzi inf-sup condition, which guarantees the stability of the scheme. In the case of the SV element the mesh, that is created as a barycentric refinement of regular triangulation, is used to satisfy the Babuška-Brezzi condition. The numerical results for two benchmark problems are shown.
Keywords:
finite element method; arbitrary Lagrangian-Eulerian method; Scott-Vogelius element; Taylor-Hood element
Available in digital repository of the ASCR
Finite element approximation of fluid structure interaction using Taylor-Hood and Scott-Vogelius elements
This paper addresses the problem of fluid flow interacting a vibrating solid cylinder described by one degree of freedom system and with fixed airfoil. The problem is described by the incompressible ...
Emerging Contaminants in Sewage Sludge: Analysis and Their Removal by Pyrolysis
Hušek, Matěj
2024 - English
The study continues with flame retardants (e.g., phosphorus-based or brominated) present in sludge, which may pose a hazard to nature and human health3,4. There is a lack of information on their pyrolysis removal and occurrence in the sludge in the Czech Republic.
Keywords:
sewage sludge; pyrolysis; PFAS; flame retardants
Available in a digital repository NRGL
Emerging Contaminants in Sewage Sludge: Analysis and Their Removal by Pyrolysis
The study continues with flame retardants (e.g., phosphorus-based or brominated) present in sludge, which may pose a hazard to nature and human health3,4. There is a lack of information on their ...
Cholinium Based Ionic Liquids: Influence of Water as a Co-solvent on Their Physico-chemical Properties and Preliminary Results for Dissolution of Biopolymers
Souvenir Zafindrajaona, Mahasoa-Salina
2024 - English
Ionic liquids (ILs) are emerging as promising alternative solvents in the field of natural substance extraction, offering significant advantages over traditional solvents. Since the last decade, we notice the increasing use of greener solvent alternatives such as Natural Deep Eutectic Solvents (NaDES) or ILs for the extraction of highly valuable compounds from natural sources such as lignocellulose. During this presentation, the influence of water on heat capacity, density, speed of sound and TGA will be discussed and the preliminary results for lignin dissolution willbe presented.
Available in a digital repository NRGL
Cholinium Based Ionic Liquids: Influence of Water as a Co-solvent on Their Physico-chemical Properties and Preliminary Results for Dissolution of Biopolymers
Ionic liquids (ILs) are emerging as promising alternative solvents in the field of natural substance extraction, offering significant advantages over traditional solvents. Since the last decade, we ...
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