No (33507)
Yes (4334)
Number of found documents:
37841
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Přeměny energie ve fyzice pohledem termokamery
2024 -
Příspěvek představuje jednoduché experimenty využitelné
ve výuce fyziky v souvislosti s vizualizací energetických pře měn – typicky jde o přeměny mechanické či elektrické ener gie na energii vnitřní. Kvalitativní pojetí experimentů umož ňuje jejich začlenění do výuky na základní i střední škole, a to
jak ve formě demonstrační, tak coby náměty na skupinovou
žákovskou práci.
Keywords:
experiment; výuka; fyzika
Available in the ZČU Library.
Přeměny energie ve fyzice pohledem termokamery
Příspěvek představuje jednoduché experimenty využitelné ve výuce fyziky v souvislosti s vizualizací energetických pře měn – typicky jde o přeměny mechanické či elektrické ener gie na energii vnitřní. ...
Porovnání tepelné vodivosti modelu jednoduchého a dvojitého okna
2024 -
Pokus je zaměřen na demonstraci rozdílu v přenosu tepla
mezi jednosklem a dvojsklem. V textu je seznam jednoduchých pomůcek a postup provádění experimentu, který je
doplněn fotografiemi a termogramy. Termogramy slouží
k vizualizaci rozdílu v chování mezi modelem jednoskla
a dvojskla. Vysvětlení je postaveno na rozdílu v tepelné vodivosti mezi polykarbonátem a vzduchem, spolu s porovnáním
měrné tepelné kapacity těchto dvou látek. Výsledky potvrzují,
že model dvojskla má nižší tepelné úniky v čase než model
jednoskla.
Keywords:
přenos teplo; jednosklo; dvojsklo
Available in the ZČU Library.
Porovnání tepelné vodivosti modelu jednoduchého a dvojitého okna
Pokus je zaměřen na demonstraci rozdílu v přenosu tepla mezi jednosklem a dvojsklem. V textu je seznam jednoduchých pomůcek a postup provádění experimentu, který je doplněn fotografiemi a ...
Computational and experimental assessment of natural frequencies in a bladed disk system
Mekhalfia, Mohammed Lamine; Procházka, Pavel; Maturkanič, Dušan; Voronova, Evgeniya; Hodboď, Robert
2024 - English
This paper examines the modal characteristics of a bladed disk in rotating machinery systems using a combination of analytical and experimental modal analysis methods. The analysis involves measuring natural frequencies and mode shapes under different operational conditions. A comparative analysis is conducted to assess modal properties obtained from both analytical and experimental approaches, while also considering the influence of rotation speed. Additionally, Finite Element Method (FEM) outputs are used to accurately position the strain gauge. Integrating these techniques provides a comprehensive understanding of the bladed disk's behaviour under varying rotational speeds, enhancing result accuracy and facilitating thorough investigation within rotating machinery systems.
Keywords:
natural frequencies; FEM; LDV; strain gauge
Available at various institutes of the ASCR
Computational and experimental assessment of natural frequencies in a bladed disk system
This paper examines the modal characteristics of a bladed disk in rotating machinery systems using a combination of analytical and experimental modal analysis methods. The analysis involves measuring ...
Applying a two degree of freedom model for drive-by identification
Bayer, Jan
2024 - English
A new concept of drive-by identification is examined applying the analogy with a Two Degree Of Freedom (DOF) system where the bridge is considered the ground-supported spring-mass and the moving spring-mass the second DOF. The response of the moving spring-mass is simulated on a bridge model using different road profiles and compared to parameters of the corresponding two DOF system. The focus is the spectral shift that can be observed on the moving spring-mass during its passage along the bridge and could possibly be applied for drive-by identification. The accuracy mainly depends on the relation of the moving spring-mass to the bridge mass and the relation between the natural frequency of the spring-mass and those of the bridge. The simulations showed that road profile can significantly reduce the accuracy of identified results, which imposes limits on practical applications.
Keywords:
drive-by identification; structural health monitoring; finite element analysis; road roughness; two DOF system
Available in digital repository of the ASCR
Applying a two degree of freedom model for drive-by identification
A new concept of drive-by identification is examined applying the analogy with a Two Degree Of Freedom (DOF) system where the bridge is considered the ground-supported spring-mass and the moving ...
Solution methods for an aeroelastic problem with combined harmonic and stochastic excitation
Fischer, Cyril; Náprstek, Jiří
2024 - English
Assessing responses in slender engineering structures facing both deterministic harmonic and stochastic excitation is often based on an approximation by the single-degree-of-freedom van der Pol-type nonlinear model. Determining the response probability density function involves solving the Fokker-Planck equation, which is generally a challenging task. Hence, semi-analytical and numerical methods come into play. This contribution reviews several possible techniques and spotlights the exponential-polynomial-closure method. The shown results are limited, as the paper reflects an early stage of the relevant research direction.
Keywords:
Fokker-Planck equation; stochastic averaging; numerical solution; Galerkin approximation; van der Pol-type oscillator; partial amplitudes; exponential-polynomial-closure method
Available in digital repository of the ASCR
Solution methods for an aeroelastic problem with combined harmonic and stochastic excitation
Assessing responses in slender engineering structures facing both deterministic harmonic and stochastic excitation is often based on an approximation by the single-degree-of-freedom van der Pol-type ...
Galloping of insulated bundled overhead line simplified analysis
Hračov, Stanislav; Macháček, Michael
2024 - English
Our paper provides an analysis of the susceptibility of a particular bundled overhead line to galloping. It presents a case study of an aerial bundled cable, consisting of four conductors insulated by polyethylene, and used for low-voltage power lines. The susceptibility to loss of stability is analyzed for cable without and with simulated icing observed on similar real conductors. In the first case, the proneness to galloping was excluded based on the results of CFD simulation and the Den Hartog criterion. In latter case, the possible occurrence of galloping was confirmed. The critical wind velocity for the ice-covered cable was calculated utilizing quasi-steady theory. Finally, the amplitudes of limit cycle oscillation for supercritical wind speeds were estimated based on simplified numerical analysis.
Keywords:
aerial bundled cable; wind effects; galloping; limit cycle oscillation
Available in digital repository of the ASCR
Galloping of insulated bundled overhead line simplified analysis
Our paper provides an analysis of the susceptibility of a particular bundled overhead line to galloping. It presents a case study of an aerial bundled cable, consisting of four conductors insulated by ...
LES simulations of airflow around rectangle with side ratio 2:1 and their comparison with experiments
Ledvinková, Blanka; Hračov, Stanislav; Macháček, Michael
2024 - English
Our contribution is focused on the comparison of the experimental investigations and of the numerical 3D LES simulations of the airflow around sharply edged rectangle with side ratio 2:1. The rectangle object was exposed to the airflow having a given velocity at different angles of the wind attack in the wind tunnel with the aim to obtain the curves of the aerodynamic coefficients and Strouhal number depending on the impact angle. The comparative numerical 3D simulations of the wind tunnel testing were performed using COMSOL Multiphysics and OpenFoam both incorporating the Large Eddy Simulation (LES) method.
Keywords:
rectangle 2:1; wind tunnel; LES simulation; aerodynamic characteristics
Available in digital repository of the ASCR
LES simulations of airflow around rectangle with side ratio 2:1 and their comparison with experiments
Our contribution is focused on the comparison of the experimental investigations and of the numerical 3D LES simulations of the airflow around sharply edged rectangle with side ratio 2:1. The ...
Development of a moodle online course for the subject of KMT/GKOB
2024 -
Keywords:
online kurz; Moodle; technická dokumentace; technické kreslení; grafická komunikace; online výuka; KMT/GKOB; Pedagogická fakulta; Západočeská univerzita v Plzni
Available in the ZČU Library.
Development of a moodle online course for the subject of KMT/GKOB
Firearms in Czech society, defence education at primary school
2024 -
Keywords:
střelné zbraně ve společnosti; branná výchova na základní škole; možnosti branné výchovy
Available in the ZČU Library.
Firearms in Czech society, defence education at primary school
Make it yourself: catalog of instructions for making didactic aids for the first grade of elementary school
2024 -
Keywords:
didaktika pracovních činností; první stupeň základní školy; materiály používané v pracovních činnostech; didaktická pomůcka; inkluzivní vzdělávání; specifické poruchy učení; tvořivost; motivace a pozornost žáků; jemná motorika; katalog
Available in the ZČU Library.
Make it yourself: catalog of instructions for making didactic aids for the first grade of elementary school
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