No (9933)
Yes (1921)
Number of found documents:
11854
Published from
to
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 ...
The Influence of Geometric Parameters of 3D Printed Structured Beds on Hydrodynamic Characteristics of Trickle-Bed Reactor
Nyklíčková, Kateřina
2024 - English
The study examines a parametric set of POCS structures, where cubic cell is the basic element. The parameters such as strut diameter sd and cell size cs were varied1. These modifications are implemented with an emphasis on maintaining similar porosity and specific surface area for these structures.
Available in digital repository of the ASCR
The Influence of Geometric Parameters of 3D Printed Structured Beds on Hydrodynamic Characteristics of Trickle-Bed Reactor
The study examines a parametric set of POCS structures, where cubic cell is the basic element. The parameters such as strut diameter sd and cell size cs were varied1. These modifications are ...
Influence of ball material on the resulting fatigue life of thermal sprayed HVOF coatings in dynamic impact testing
Duliškovič, J.; Daniel, Josef; Houdková, Š.
2024 - English
Dynamic impact wear, i.e. contact between two components in the presence of high cyclic local loads, is a challenging failure mode that occurs in many mechanical applications. Many previous studies have confirmed that dynamic impact testing is suitable for evaluating the contact fatigue of thermal sprayed coatings. However, the effect of the test parameters on the resulting lifetime is unclear. The aim of this study describes the effect of the ball material used in the dynamic impact test on the resulting fatigue life of the HVOF thermal sprayed coating. Three test balls made of WC/Co alloy, Si3N4 silicon nitride and 440 C steel were chosen for this study. Dynamic impaction testing was carried out on the Cr3C2-NiCr coating, which was sprayed by HVOF on a 1.2376 high-speed steel substrate. The impact lifetime was described by the number of critical impacts, i.e. the number of impacts before coating fatigue occurs. Furthermore, the depth and volume of impact craters were measured. Using scanning electron microscopy (SEM), the surface of the impacts as well as the microstructure of the coating on the cross-section in the region of the impacts were observed. Furthermore, the mechanism of crack propagation in the coating and the microstructure of the indentor were investigated.
Keywords:
dynamic impact test; HVOF; Cr3C2-NiCr; fatigue
Available at various institutes of the ASCR
Influence of ball material on the resulting fatigue life of thermal sprayed HVOF coatings in dynamic impact testing
Dynamic impact wear, i.e. contact between two components in the presence of high cyclic local loads, is a challenging failure mode that occurs in many mechanical applications. Many previous studies ...
Functional Tungsten-based thin films and their characterization
Košelová, Zuzana; Horáková, L.; Sobola, Dinara; Burda, Daniel; Knápek, Alexandr; Fohlerová, Z.
2024 - English
Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten is still a common choice for cold field emitters in commercial microscopy applications. Its suitable quality can be further improved by thin film deposition. Not only the emission characteristic can be improved, but also the emitter operating time can be extended. Tungsten oxide is known for its excellent resistance to corrosion and chemical attack due to its stable crystal structure and strong chemical bonds between tungsten and oxygen atoms. Many techniques with different advantages and disadvantages have been used for this purpose. Anodization was chosen for this work because of the controllable uniform coverage of the material and its easy availability without the need for expensive complex equipment. The anodizing process involves applying an electrical potential to tungsten while it is immersed in an electrolyte solution. This creates a thin layer of tungsten oxide on the surface of the metal. The thickness and properties of the resulting oxide layer can be controlled by adjusting the anodization conditions, such as the electrolyte solution, voltage, and the duration of the process. In this work, H3PO4 was used as the electrolyte to test whether these tungsten oxide layers would be useful for electron emitters, for use in electron guns and other devices that require high-quality electron emitters. The properties were evaluated using appropriate techniques. In general, anodization of tungsten to form thin layers of tungsten oxide layers is a promising technique for producing high quality electron emitters.
Keywords:
cold-field emission; thin layer deposition; tungsten oxide; resonance enhanced tunneling; anodization
Available at various institutes of the ASCR
Functional Tungsten-based thin films and their characterization
Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten ...
Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding
Šebestová, Hana; Horník, Petr; Mika, Filip; Mikmeková, Šárka; Ambrož, Ondřej; Mrňa, Libor
2024 - English
Weld microstructure depends on the characteristics of welded materials and parameters of welding technology, especially on the heat input that determines the peak temperature and the cooling rate. When the coated sheets are welded, the effect of the chemical composition of the coating must be also considered even though its thickness is only a few tens of microns. During 22MnB5+AlSi laser welding experiments, the ferrite-stabilizing elements of coating modified the weld metal microstructure. Ferrite appeared in a quenched weld metal. The rapid cooling rate accompanying welding with a focused beam limited the homogenization of the weld metal which resulted in the formation of ferritic bands in the regions rich in Si and especially in Al. On the other hand, a high level of homogenization was reached when welding with the defocused beam. The ferritic islands uniformly distributed in the weld metal were formed at 0.4 wt% and 1.6 wt% of Si and Al, respectively. The doubled heat input reduced the Al content to 0.7 wt% insufficient for the ferrite formation at still relatively high cooling rates. Predicting the distribution of ferrite in the weld metal is challenging due to its dependence on various factors, such as cooling rate and the volume of dissolved coating, which may vary with any modifications made to the welding parameters.
Keywords:
laser welding; high-strength steel; microstructure; heat input; ferrite stabilization
Available at various institutes of the ASCR
Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding
Weld microstructure depends on the characteristics of welded materials and parameters of welding technology, especially on the heat input that determines the peak temperature and the cooling rate. ...
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 ...
Surfactant-free silver nanofluids as liquid systems with neuromorphic potential
Nikitin, D.; Biliak, K.; Lemke, J.; Protsak, M.; Pleskunov, P.; Tosca, M.; Ali-Ogly, S.; Červenková, V.; Adejube, B.; Bajtošová, L.; Černochová, Zulfiya; Prokeš, J.; Křivka, I.; Biederman, H.; Faupel, F.; Vahl, A.; Choukourov, A.
2024 - English
Neuromorphic engineering is a rapidly developing branch of science that aims to implement the unique attributes of biological neural networks in artificial devices. Most neuromorphic devices are based on the resistive switching effect, which involves changing the device’s conductivity in response to an external electric field. For instance, percolating nanoparticle (NP) networks produced by gas aggregation cluster sources (GAS) show collective spiking behavior in conductivity reminiscent of brain-like dynamics. Nevertheless, the problem of dynamic spatial reconfiguration in solid-state neuromorphic systems remains unsolved. Herein, novel nanofluids with resistive switching properties are proposed as neuromorphic media. They are produced by depositing silver NPs from GAS into vacuum-compatible liquids (paraffin, silicon oil, and PEG) without the use of surfactants or other chemicals. When the electric field is applied between two electrodes, the migration of NPs toward biased electrode is detected in all liquids. The electrophoretic nature of the NP movement was proved by means of ζ-potential measurements. Such movement led to the self-assembly of NPs in conductive paths connecting the electrodes and, as a result, to resistive switching. The electrical response was strongly dependent on the dielectric constant of the base liquid. The Ag-PEG nanofluid demonstrated the best switching performance reproducible during several tens of current-voltage cycles. The growth of flexible and reconfigurable conductive filaments in nanofluids makes them suitable media for potential realization of 3D neural networks.
Keywords:
nanofluid; gas aggregation cluster source; ζ-potential, electrophoresis
Available at various institutes of the ASCR
Surfactant-free silver nanofluids as liquid systems with neuromorphic potential
Neuromorphic engineering is a rapidly developing branch of science that aims to implement the unique attributes of biological neural networks in artificial devices. Most neuromorphic devices are based ...
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