Approaches to the computational modelling of soft tissues related to cutting
2024 - Keywords: měkké tkáně; výpočetní modelování; simulace Available in the ZČU Library. Approaches to the computational modelling of soft tissues related to cutting

Západočeská univerzita v Plzni, 2024

Voice-Interactive Semantic Search Interface with Vector Databases
2024 - Keywords: sémantické vyhledávání; vektorová databáze; hlas Available in the ZČU Library. Voice-Interactive Semantic Search Interface with Vector Databases

Západočeská univerzita v Plzni, 2024

Image Domain Transfer for Liver Analysis in Histology
2024 - Keywords: CycleGAN; převod domény obrázku; játra; histologie Available in the ZČU Library. Image Domain Transfer for Liver Analysis in Histology

Západočeská univerzita v Plzni, 2024

Deep learning methods for Motor Imagery EEG Signal Classification
2024 - Keywords: hluboké učení; EEG signal; motor Available in the ZČU Library. Deep learning methods for Motor Imagery EEG Signal Classification

Západočeská univerzita v Plzni, 2024

Mobilní aplikace pro včelaře
2024 - Keywords: včelař; mobilní aplikace; monitorování Available in the ZČU Library. Mobilní aplikace pro včelaře

Západočeská univerzita v Plzni, 2024

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 ...

Vacek, Karel; Sváček, P.
Matematický ústav, 2024

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. ...

Šebestová, Hana; Horník, Petr; Mika, Filip; Mikmeková, Šárka; Ambrož, Ondřej; Mrňa, Libor
Ústav přístrojové techniky, 2024

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 ...

Duliškovič, J.; Daniel, Josef; Houdková, Š.
Ústav přístrojové techniky, 2024

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 ...

Košelová, Zuzana; Horáková, L.; Sobola, Dinara; Burda, Daniel; Knápek, Alexandr; Fohlerová, Z.
Ústav přístrojové techniky, 2024

Termokamery jako prostředek pro oživení výuky matematiky
2024 - Termokamery nemají využití pouze v předmětech jako je fyzika, biologie či chemie. Navrhli jsme možnosti, jakým způ sobem termokamery zařadit do výuky matematiky s cílem zatraktivnění klasického vyučování a využití mezioborových vztahů. Metody, které jsme zvolili, neslouží k přímému osvo jování matematických poznatků, jsou vhodné spíše k procvi čení učiva zábavnou formou s využitím moderních technolo gií. Keywords: matematika; výuka; termokamera Available in the ZČU Library. Termokamery jako prostředek pro oživení výuky matematiky

Termokamery nemají využití pouze v předmětech jako je fyzika, biologie či chemie. Navrhli jsme možnosti, jakým způ sobem termokamery zařadit do výuky matematiky s cílem zatraktivnění klasického ...

Západočeská univerzita v Plzni, 2024